August 2019 - tor-commits - lists.torproject.org

[tor/maint-0.3.5] Merge remote-tracking branch 'nickm/ticket30454_034_01_squashed' into ticket30454_035_01
by teor＠torproject.org 12 Aug '19

12 Aug '19

commit 245dccb77d79dc432bb7aab21ce2c893da4b602a Merge: e5deb2bbc 56908c6f1 Author: David Goulet <dgoulet(a)torproject.org> Date: Wed May 22 11:43:55 2019 -0400 Merge remote-tracking branch 'nickm/ticket30454_034_01_squashed' into ticket30454_035_01 changes/ticket30454 | 10 ++++++++ src/feature/hs/hs_cell.c | 16 +++++++------ src/feature/hs/hs_cell.h | 13 ---------- src/feature/hs/hs_client.c | 18 +++++++------- src/feature/hs/hs_intropoint.c | 27 +++++++++++---------- src/feature/hs/hs_intropoint.h | 15 ------------ src/test/test_hs_cell.c | 2 +- src/test/test_hs_intropoint.c | 4 ++-- src/trunnel/hs/cell_introduce1.c | 44 +++++++++++++--------------------- src/trunnel/hs/cell_introduce1.h | 7 ++++++ src/trunnel/hs/cell_introduce1.trunnel | 21 +++++++++++++--- 11 files changed, 87 insertions(+), 90 deletions(-) diff --cc src/feature/hs/hs_cell.c index 597982b34,000000000..613ffe726 mode 100644,000000..100644 --- a/src/feature/hs/hs_cell.c +++ b/src/feature/hs/hs_cell.c @@@ -1,950 -1,0 +1,952 @@@ +/* Copyright (c) 2017-2019, The Tor Project, Inc. */ +/* See LICENSE for licensing information */ + +/** + * \file hs_cell.c + * \brief Hidden service API for cell creation and handling. + **/ + +#include "core/or/or.h" +#include "app/config/config.h" +#include "lib/crypt_ops/crypto_util.h" +#include "feature/rend/rendservice.h" +#include "feature/hs_common/replaycache.h" + +#include "feature/hs/hs_cell.h" +#include "core/crypto/hs_ntor.h" + +#include "core/or/origin_circuit_st.h" + +/* Trunnel. */ +#include "trunnel/ed25519_cert.h" +#include "trunnel/hs/cell_common.h" +#include "trunnel/hs/cell_establish_intro.h" +#include "trunnel/hs/cell_introduce1.h" +#include "trunnel/hs/cell_rendezvous.h" + +/* Compute the MAC of an INTRODUCE cell in mac_out. The encoded_cell param is + * the cell content up to the ENCRYPTED section of length encoded_cell_len. + * The encrypted param is the start of the ENCRYPTED section of length + * encrypted_len. The mac_key is the key needed for the computation of the MAC + * derived from the ntor handshake of length mac_key_len. + * + * The length mac_out_len must be at least DIGEST256_LEN. */ +static void +compute_introduce_mac(const uint8_t *encoded_cell, size_t encoded_cell_len, + const uint8_t *encrypted, size_t encrypted_len, + const uint8_t *mac_key, size_t mac_key_len, + uint8_t *mac_out, size_t mac_out_len) +{ + size_t offset = 0; + size_t mac_msg_len; + uint8_t mac_msg[RELAY_PAYLOAD_SIZE] = {0}; + + tor_assert(encoded_cell); + tor_assert(encrypted); + tor_assert(mac_key); + tor_assert(mac_out); + tor_assert(mac_out_len >= DIGEST256_LEN); + + /* Compute the size of the message which is basically the entire cell until + * the MAC field of course. */ + mac_msg_len = encoded_cell_len + (encrypted_len - DIGEST256_LEN); + tor_assert(mac_msg_len <= sizeof(mac_msg)); + + /* First, put the encoded cell in the msg. */ + memcpy(mac_msg, encoded_cell, encoded_cell_len); + offset += encoded_cell_len; + /* Second, put the CLIENT_PK + ENCRYPTED_DATA but ommit the MAC field (which + * is junk at this point). */ + memcpy(mac_msg + offset, encrypted, (encrypted_len - DIGEST256_LEN)); + offset += (encrypted_len - DIGEST256_LEN); + tor_assert(offset == mac_msg_len); + + crypto_mac_sha3_256(mac_out, mac_out_len, + mac_key, mac_key_len, + mac_msg, mac_msg_len); + memwipe(mac_msg, 0, sizeof(mac_msg)); +} + +/* From a set of keys, subcredential and the ENCRYPTED section of an + * INTRODUCE2 cell, return a newly allocated intro cell keys structure. + * Finally, the client public key is copied in client_pk. On error, return + * NULL. */ +static hs_ntor_intro_cell_keys_t * +get_introduce2_key_material(const ed25519_public_key_t *auth_key, + const curve25519_keypair_t *enc_key, + const uint8_t *subcredential, + const uint8_t *encrypted_section, + curve25519_public_key_t *client_pk) +{ + hs_ntor_intro_cell_keys_t *keys; + + tor_assert(auth_key); + tor_assert(enc_key); + tor_assert(subcredential); + tor_assert(encrypted_section); + tor_assert(client_pk); + + keys = tor_malloc_zero(sizeof(*keys)); + + /* First bytes of the ENCRYPTED section are the client public key. */ + memcpy(client_pk->public_key, encrypted_section, CURVE25519_PUBKEY_LEN); + + if (hs_ntor_service_get_introduce1_keys(auth_key, enc_key, client_pk, + subcredential, keys) < 0) { + /* Don't rely on the caller to wipe this on error. */ + memwipe(client_pk, 0, sizeof(curve25519_public_key_t)); + tor_free(keys); + keys = NULL; + } + return keys; +} + +/* Using the given encryption key, decrypt the encrypted_section of length + * encrypted_section_len of an INTRODUCE2 cell and return a newly allocated + * buffer containing the decrypted data. On decryption failure, NULL is + * returned. */ +static uint8_t * +decrypt_introduce2(const uint8_t *enc_key, const uint8_t *encrypted_section, + size_t encrypted_section_len) +{ + uint8_t *decrypted = NULL; + crypto_cipher_t *cipher = NULL; + + tor_assert(enc_key); + tor_assert(encrypted_section); + + /* Decrypt ENCRYPTED section. */ + cipher = crypto_cipher_new_with_bits((char *) enc_key, + CURVE25519_PUBKEY_LEN * 8); + tor_assert(cipher); + + /* This is symmetric encryption so can't be bigger than the encrypted + * section length. */ + decrypted = tor_malloc_zero(encrypted_section_len); + if (crypto_cipher_decrypt(cipher, (char *) decrypted, + (const char *) encrypted_section, + encrypted_section_len) < 0) { + tor_free(decrypted); + decrypted = NULL; + goto done; + } + + done: + crypto_cipher_free(cipher); + return decrypted; +} + +/* Given a pointer to the decrypted data of the ENCRYPTED section of an + * INTRODUCE2 cell of length decrypted_len, parse and validate the cell + * content. Return a newly allocated cell structure or NULL on error. The + * circuit and service object are only used for logging purposes. */ +static trn_cell_introduce_encrypted_t * +parse_introduce2_encrypted(const uint8_t *decrypted_data, + size_t decrypted_len, const origin_circuit_t *circ, + const hs_service_t *service) +{ + trn_cell_introduce_encrypted_t *enc_cell = NULL; + + tor_assert(decrypted_data); + tor_assert(circ); + tor_assert(service); + + if (trn_cell_introduce_encrypted_parse(&enc_cell, decrypted_data, + decrypted_len) < 0) { + log_info(LD_REND, "Unable to parse the decrypted ENCRYPTED section of " + "the INTRODUCE2 cell on circuit %u for service %s", + TO_CIRCUIT(circ)->n_circ_id, + safe_str_client(service->onion_address)); + goto err; + } + + if (trn_cell_introduce_encrypted_get_onion_key_type(enc_cell) != - HS_CELL_ONION_KEY_TYPE_NTOR) { ++ TRUNNEL_HS_INTRO_ONION_KEY_TYPE_NTOR) { + log_info(LD_REND, "INTRODUCE2 onion key type is invalid. Got %u but " + "expected %u on circuit %u for service %s", + trn_cell_introduce_encrypted_get_onion_key_type(enc_cell), - HS_CELL_ONION_KEY_TYPE_NTOR, TO_CIRCUIT(circ)->n_circ_id, ++ TRUNNEL_HS_INTRO_ONION_KEY_TYPE_NTOR, ++ TO_CIRCUIT(circ)->n_circ_id, + safe_str_client(service->onion_address)); + goto err; + } + + if (trn_cell_introduce_encrypted_getlen_onion_key(enc_cell) != + CURVE25519_PUBKEY_LEN) { + log_info(LD_REND, "INTRODUCE2 onion key length is invalid. Got %u but " + "expected %d on circuit %u for service %s", + (unsigned)trn_cell_introduce_encrypted_getlen_onion_key(enc_cell), + CURVE25519_PUBKEY_LEN, TO_CIRCUIT(circ)->n_circ_id, + safe_str_client(service->onion_address)); + goto err; + } + /* XXX: Validate NSPEC field as well. */ + + return enc_cell; + err: + trn_cell_introduce_encrypted_free(enc_cell); + return NULL; +} + +/* Build a legacy ESTABLISH_INTRO cell with the given circuit nonce and RSA + * encryption key. The encoded cell is put in cell_out that MUST at least be + * of the size of RELAY_PAYLOAD_SIZE. Return the encoded cell length on + * success else a negative value and cell_out is untouched. */ +static ssize_t +build_legacy_establish_intro(const char *circ_nonce, crypto_pk_t *enc_key, + uint8_t *cell_out) +{ + ssize_t cell_len; + + tor_assert(circ_nonce); + tor_assert(enc_key); + tor_assert(cell_out); + + memwipe(cell_out, 0, RELAY_PAYLOAD_SIZE); + + cell_len = rend_service_encode_establish_intro_cell((char*)cell_out, + RELAY_PAYLOAD_SIZE, + enc_key, circ_nonce); + return cell_len; +} + +/* Parse an INTRODUCE2 cell from payload of size payload_len for the given + * service and circuit which are used only for logging purposes. The resulting + * parsed cell is put in cell_ptr_out. + * + * This function only parses prop224 INTRODUCE2 cells even when the intro point + * is a legacy intro point. That's because intro points don't actually care + * about the contents of the introduce cell. Legacy INTRODUCE cells are only + * used by the legacy system now. + * + * Return 0 on success else a negative value and cell_ptr_out is untouched. */ +static int +parse_introduce2_cell(const hs_service_t *service, + const origin_circuit_t *circ, const uint8_t *payload, + size_t payload_len, + trn_cell_introduce1_t **cell_ptr_out) +{ + trn_cell_introduce1_t *cell = NULL; + + tor_assert(service); + tor_assert(circ); + tor_assert(payload); + tor_assert(cell_ptr_out); + + /* Parse the cell so we can start cell validation. */ + if (trn_cell_introduce1_parse(&cell, payload, payload_len) < 0) { + log_info(LD_PROTOCOL, "Unable to parse INTRODUCE2 cell on circuit %u " + "for service %s", + TO_CIRCUIT(circ)->n_circ_id, + safe_str_client(service->onion_address)); + goto err; + } + + /* Success. */ + *cell_ptr_out = cell; + return 0; + err: + return -1; +} + +/* Set the onion public key onion_pk in cell, the encrypted section of an + * INTRODUCE1 cell. */ +static void +introduce1_set_encrypted_onion_key(trn_cell_introduce_encrypted_t *cell, + const uint8_t *onion_pk) +{ + tor_assert(cell); + tor_assert(onion_pk); + /* There is only one possible key type for a non legacy cell. */ + trn_cell_introduce_encrypted_set_onion_key_type(cell, - HS_CELL_ONION_KEY_TYPE_NTOR); ++ TRUNNEL_HS_INTRO_ONION_KEY_TYPE_NTOR); + trn_cell_introduce_encrypted_set_onion_key_len(cell, CURVE25519_PUBKEY_LEN); + trn_cell_introduce_encrypted_setlen_onion_key(cell, CURVE25519_PUBKEY_LEN); + memcpy(trn_cell_introduce_encrypted_getarray_onion_key(cell), onion_pk, + trn_cell_introduce_encrypted_getlen_onion_key(cell)); +} + +/* Set the link specifiers in lspecs in cell, the encrypted section of an + * INTRODUCE1 cell. */ +static void +introduce1_set_encrypted_link_spec(trn_cell_introduce_encrypted_t *cell, + const smartlist_t *lspecs) +{ + tor_assert(cell); + tor_assert(lspecs); + tor_assert(smartlist_len(lspecs) > 0); + tor_assert(smartlist_len(lspecs) <= UINT8_MAX); + + uint8_t lspecs_num = (uint8_t) smartlist_len(lspecs); + trn_cell_introduce_encrypted_set_nspec(cell, lspecs_num); + /* We aren't duplicating the link specifiers object here which means that + * the ownership goes to the trn_cell_introduce_encrypted_t cell and those + * object will be freed when the cell is. */ + SMARTLIST_FOREACH(lspecs, link_specifier_t *, ls, + trn_cell_introduce_encrypted_add_nspecs(cell, ls)); +} + +/* Set padding in the enc_cell only if needed that is the total length of both + * sections are below the mininum required for an INTRODUCE1 cell. */ +static void +introduce1_set_encrypted_padding(const trn_cell_introduce1_t *cell, + trn_cell_introduce_encrypted_t *enc_cell) +{ + tor_assert(cell); + tor_assert(enc_cell); + /* This is the length we expect to have once encoded of the whole cell. */ + ssize_t full_len = trn_cell_introduce1_encoded_len(cell) + + trn_cell_introduce_encrypted_encoded_len(enc_cell); + tor_assert(full_len > 0); + if (full_len < HS_CELL_INTRODUCE1_MIN_SIZE) { + size_t padding = HS_CELL_INTRODUCE1_MIN_SIZE - full_len; + trn_cell_introduce_encrypted_setlen_pad(enc_cell, padding); + memset(trn_cell_introduce_encrypted_getarray_pad(enc_cell), 0, + trn_cell_introduce_encrypted_getlen_pad(enc_cell)); + } +} + +/* Encrypt the ENCRYPTED payload and encode it in the cell using the enc_cell + * and the INTRODUCE1 data. + * + * This can't fail but it is very important that the caller sets every field + * in data so the computation of the INTRODUCE1 keys doesn't fail. */ +static void +introduce1_encrypt_and_encode(trn_cell_introduce1_t *cell, + const trn_cell_introduce_encrypted_t *enc_cell, + const hs_cell_introduce1_data_t *data) +{ + size_t offset = 0; + ssize_t encrypted_len; + ssize_t encoded_cell_len, encoded_enc_cell_len; + uint8_t encoded_cell[RELAY_PAYLOAD_SIZE] = {0}; + uint8_t encoded_enc_cell[RELAY_PAYLOAD_SIZE] = {0}; + uint8_t *encrypted = NULL; + uint8_t mac[DIGEST256_LEN]; + crypto_cipher_t *cipher = NULL; + hs_ntor_intro_cell_keys_t keys; + + tor_assert(cell); + tor_assert(enc_cell); + tor_assert(data); + + /* Encode the cells up to now of what we have to we can perform the MAC + * computation on it. */ + encoded_cell_len = trn_cell_introduce1_encode(encoded_cell, + sizeof(encoded_cell), cell); + /* We have a much more serious issue if this isn't true. */ + tor_assert(encoded_cell_len > 0); + + encoded_enc_cell_len = + trn_cell_introduce_encrypted_encode(encoded_enc_cell, + sizeof(encoded_enc_cell), enc_cell); + /* We have a much more serious issue if this isn't true. */ + tor_assert(encoded_enc_cell_len > 0); + + /* Get the key material for the encryption. */ + if (hs_ntor_client_get_introduce1_keys(data->auth_pk, data->enc_pk, + data->client_kp, + data->subcredential, &keys) < 0) { + tor_assert_unreached(); + } + + /* Prepare cipher with the encryption key just computed. */ + cipher = crypto_cipher_new_with_bits((const char *) keys.enc_key, + sizeof(keys.enc_key) * 8); + tor_assert(cipher); + + /* Compute the length of the ENCRYPTED section which is the CLIENT_PK, + * ENCRYPTED_DATA and MAC length. */ + encrypted_len = sizeof(data->client_kp->pubkey) + encoded_enc_cell_len + + sizeof(mac); + tor_assert(encrypted_len < RELAY_PAYLOAD_SIZE); + encrypted = tor_malloc_zero(encrypted_len); + + /* Put the CLIENT_PK first. */ + memcpy(encrypted, data->client_kp->pubkey.public_key, + sizeof(data->client_kp->pubkey.public_key)); + offset += sizeof(data->client_kp->pubkey.public_key); + /* Then encrypt and set the ENCRYPTED_DATA. This can't fail. */ + crypto_cipher_encrypt(cipher, (char *) encrypted + offset, + (const char *) encoded_enc_cell, encoded_enc_cell_len); + crypto_cipher_free(cipher); + offset += encoded_enc_cell_len; + /* Compute MAC from the above and put it in the buffer. This function will + * make the adjustment to the encrypted_len to omit the MAC length. */ + compute_introduce_mac(encoded_cell, encoded_cell_len, + encrypted, encrypted_len, + keys.mac_key, sizeof(keys.mac_key), + mac, sizeof(mac)); + memcpy(encrypted + offset, mac, sizeof(mac)); + offset += sizeof(mac); + tor_assert(offset == (size_t) encrypted_len); + + /* Set the ENCRYPTED section in the cell. */ + trn_cell_introduce1_setlen_encrypted(cell, encrypted_len); + memcpy(trn_cell_introduce1_getarray_encrypted(cell), + encrypted, encrypted_len); + + /* Cleanup. */ + memwipe(&keys, 0, sizeof(keys)); + memwipe(mac, 0, sizeof(mac)); + memwipe(encrypted, 0, sizeof(encrypted_len)); + memwipe(encoded_enc_cell, 0, sizeof(encoded_enc_cell)); + tor_free(encrypted); +} + +/* Using the INTRODUCE1 data, setup the ENCRYPTED section in cell. This means + * set it, encrypt it and encode it. */ +static void +introduce1_set_encrypted(trn_cell_introduce1_t *cell, + const hs_cell_introduce1_data_t *data) +{ + trn_cell_introduce_encrypted_t *enc_cell; + trn_cell_extension_t *ext; + + tor_assert(cell); + tor_assert(data); + + enc_cell = trn_cell_introduce_encrypted_new(); + tor_assert(enc_cell); + + /* Set extension data. None are used. */ + ext = trn_cell_extension_new(); + tor_assert(ext); + trn_cell_extension_set_num(ext, 0); + trn_cell_introduce_encrypted_set_extensions(enc_cell, ext); + + /* Set the rendezvous cookie. */ + memcpy(trn_cell_introduce_encrypted_getarray_rend_cookie(enc_cell), + data->rendezvous_cookie, REND_COOKIE_LEN); + + /* Set the onion public key. */ + introduce1_set_encrypted_onion_key(enc_cell, data->onion_pk->public_key); + + /* Set the link specifiers. */ + introduce1_set_encrypted_link_spec(enc_cell, data->link_specifiers); + + /* Set padding. */ + introduce1_set_encrypted_padding(cell, enc_cell); + + /* Encrypt and encode it in the cell. */ + introduce1_encrypt_and_encode(cell, enc_cell, data); + + /* Cleanup. */ + trn_cell_introduce_encrypted_free(enc_cell); +} + +/* Set the authentication key in the INTRODUCE1 cell from the given data. */ +static void +introduce1_set_auth_key(trn_cell_introduce1_t *cell, + const hs_cell_introduce1_data_t *data) +{ + tor_assert(cell); + tor_assert(data); + /* There is only one possible type for a non legacy cell. */ - trn_cell_introduce1_set_auth_key_type(cell, HS_INTRO_AUTH_KEY_TYPE_ED25519); ++ trn_cell_introduce1_set_auth_key_type(cell, ++ TRUNNEL_HS_INTRO_AUTH_KEY_TYPE_ED25519); + trn_cell_introduce1_set_auth_key_len(cell, ED25519_PUBKEY_LEN); + trn_cell_introduce1_setlen_auth_key(cell, ED25519_PUBKEY_LEN); + memcpy(trn_cell_introduce1_getarray_auth_key(cell), + data->auth_pk->pubkey, trn_cell_introduce1_getlen_auth_key(cell)); +} + +/* Set the legacy ID field in the INTRODUCE1 cell from the given data. */ +static void +introduce1_set_legacy_id(trn_cell_introduce1_t *cell, + const hs_cell_introduce1_data_t *data) +{ + tor_assert(cell); + tor_assert(data); + + if (data->is_legacy) { + uint8_t digest[DIGEST_LEN]; + if (BUG(crypto_pk_get_digest(data->legacy_key, (char *) digest) < 0)) { + return; + } + memcpy(trn_cell_introduce1_getarray_legacy_key_id(cell), + digest, trn_cell_introduce1_getlen_legacy_key_id(cell)); + } else { + /* We have to zeroed the LEGACY_KEY_ID field. */ + memset(trn_cell_introduce1_getarray_legacy_key_id(cell), 0, + trn_cell_introduce1_getlen_legacy_key_id(cell)); + } +} + +/* ========== */ +/* Public API */ +/* ========== */ + +/* Build an ESTABLISH_INTRO cell with the given circuit nonce and intro point + * object. The encoded cell is put in cell_out that MUST at least be of the + * size of RELAY_PAYLOAD_SIZE. Return the encoded cell length on success else + * a negative value and cell_out is untouched. This function also supports + * legacy cell creation. */ +ssize_t +hs_cell_build_establish_intro(const char *circ_nonce, + const hs_service_intro_point_t *ip, + uint8_t *cell_out) +{ + ssize_t cell_len = -1; + uint16_t sig_len = ED25519_SIG_LEN; + trn_cell_extension_t *ext; + trn_cell_establish_intro_t *cell = NULL; + + tor_assert(circ_nonce); + tor_assert(ip); + + /* Quickly handle the legacy IP. */ + if (ip->base.is_only_legacy) { + tor_assert(ip->legacy_key); + cell_len = build_legacy_establish_intro(circ_nonce, ip->legacy_key, + cell_out); + tor_assert(cell_len <= RELAY_PAYLOAD_SIZE); + /* Success or not we are done here. */ + goto done; + } + + /* Set extension data. None used here. */ + ext = trn_cell_extension_new(); + trn_cell_extension_set_num(ext, 0); + cell = trn_cell_establish_intro_new(); + trn_cell_establish_intro_set_extensions(cell, ext); + /* Set signature size. Array is then allocated in the cell. We need to do + * this early so we can use trunnel API to get the signature length. */ + trn_cell_establish_intro_set_sig_len(cell, sig_len); + trn_cell_establish_intro_setlen_sig(cell, sig_len); + + /* Set AUTH_KEY_TYPE: 2 means ed25519 */ + trn_cell_establish_intro_set_auth_key_type(cell, - HS_INTRO_AUTH_KEY_TYPE_ED25519); ++ TRUNNEL_HS_INTRO_AUTH_KEY_TYPE_ED25519); + + /* Set AUTH_KEY and AUTH_KEY_LEN field. Must also set byte-length of + * AUTH_KEY to match */ + { + uint16_t auth_key_len = ED25519_PUBKEY_LEN; + trn_cell_establish_intro_set_auth_key_len(cell, auth_key_len); + trn_cell_establish_intro_setlen_auth_key(cell, auth_key_len); + /* We do this call _after_ setting the length because it's reallocated at + * that point only. */ + uint8_t *auth_key_ptr = trn_cell_establish_intro_getarray_auth_key(cell); + memcpy(auth_key_ptr, ip->auth_key_kp.pubkey.pubkey, auth_key_len); + } + + /* Calculate HANDSHAKE_AUTH field (MAC). */ + { + ssize_t tmp_cell_enc_len = 0; + ssize_t tmp_cell_mac_offset = + sig_len + sizeof(cell->sig_len) + + trn_cell_establish_intro_getlen_handshake_mac(cell); + uint8_t tmp_cell_enc[RELAY_PAYLOAD_SIZE] = {0}; + uint8_t mac[TRUNNEL_SHA3_256_LEN], *handshake_ptr; + + /* We first encode the current fields we have in the cell so we can + * compute the MAC using the raw bytes. */ + tmp_cell_enc_len = trn_cell_establish_intro_encode(tmp_cell_enc, + sizeof(tmp_cell_enc), + cell); + if (BUG(tmp_cell_enc_len < 0)) { + goto done; + } + /* Sanity check. */ + tor_assert(tmp_cell_enc_len > tmp_cell_mac_offset); + + /* Circuit nonce is always DIGEST_LEN according to tor-spec.txt. */ + crypto_mac_sha3_256(mac, sizeof(mac), + (uint8_t *) circ_nonce, DIGEST_LEN, + tmp_cell_enc, tmp_cell_enc_len - tmp_cell_mac_offset); + handshake_ptr = trn_cell_establish_intro_getarray_handshake_mac(cell); + memcpy(handshake_ptr, mac, sizeof(mac)); + + memwipe(mac, 0, sizeof(mac)); + memwipe(tmp_cell_enc, 0, sizeof(tmp_cell_enc)); + } + + /* Calculate the cell signature SIG. */ + { + ssize_t tmp_cell_enc_len = 0; + ssize_t tmp_cell_sig_offset = (sig_len + sizeof(cell->sig_len)); + uint8_t tmp_cell_enc[RELAY_PAYLOAD_SIZE] = {0}, *sig_ptr; + ed25519_signature_t sig; + + /* We first encode the current fields we have in the cell so we can + * compute the signature from the raw bytes of the cell. */ + tmp_cell_enc_len = trn_cell_establish_intro_encode(tmp_cell_enc, + sizeof(tmp_cell_enc), + cell); + if (BUG(tmp_cell_enc_len < 0)) { + goto done; + } + + if (ed25519_sign_prefixed(&sig, tmp_cell_enc, + tmp_cell_enc_len - tmp_cell_sig_offset, + ESTABLISH_INTRO_SIG_PREFIX, &ip->auth_key_kp)) { + log_warn(LD_BUG, "Unable to make signature for ESTABLISH_INTRO cell."); + goto done; + } + /* Copy the signature into the cell. */ + sig_ptr = trn_cell_establish_intro_getarray_sig(cell); + memcpy(sig_ptr, sig.sig, sig_len); + + memwipe(tmp_cell_enc, 0, sizeof(tmp_cell_enc)); + } + + /* Encode the cell. Can't be bigger than a standard cell. */ + cell_len = trn_cell_establish_intro_encode(cell_out, RELAY_PAYLOAD_SIZE, + cell); + + done: + trn_cell_establish_intro_free(cell); + return cell_len; +} + +/* Parse the INTRO_ESTABLISHED cell in the payload of size payload_len. If we + * are successful at parsing it, return the length of the parsed cell else a + * negative value on error. */ +ssize_t +hs_cell_parse_intro_established(const uint8_t *payload, size_t payload_len) +{ + ssize_t ret; + trn_cell_intro_established_t *cell = NULL; + + tor_assert(payload); + + /* Try to parse the payload into a cell making sure we do actually have a + * valid cell. */ + ret = trn_cell_intro_established_parse(&cell, payload, payload_len); + if (ret >= 0) { + /* On success, we do not keep the cell, we just notify the caller that it + * was successfully parsed. */ + trn_cell_intro_established_free(cell); + } + return ret; +} + +/* Parse the INTRODUCE2 cell using data which contains everything we need to + * do so and contains the destination buffers of information we extract and + * compute from the cell. Return 0 on success else a negative value. The + * service and circ are only used for logging purposes. */ +ssize_t +hs_cell_parse_introduce2(hs_cell_introduce2_data_t *data, + const origin_circuit_t *circ, + const hs_service_t *service) +{ + int ret = -1; + time_t elapsed; + uint8_t *decrypted = NULL; + size_t encrypted_section_len; + const uint8_t *encrypted_section; + trn_cell_introduce1_t *cell = NULL; + trn_cell_introduce_encrypted_t *enc_cell = NULL; + hs_ntor_intro_cell_keys_t *intro_keys = NULL; + + tor_assert(data); + tor_assert(circ); + tor_assert(service); + + /* Parse the cell into a decoded data structure pointed by cell_ptr. */ + if (parse_introduce2_cell(service, circ, data->payload, data->payload_len, + &cell) < 0) { + goto done; + } + + log_info(LD_REND, "Received a decodable INTRODUCE2 cell on circuit %u " + "for service %s. Decoding encrypted section...", + TO_CIRCUIT(circ)->n_circ_id, + safe_str_client(service->onion_address)); + + encrypted_section = trn_cell_introduce1_getconstarray_encrypted(cell); + encrypted_section_len = trn_cell_introduce1_getlen_encrypted(cell); + + /* Encrypted section must at least contain the CLIENT_PK and MAC which is + * defined in section 3.3.2 of the specification. */ + if (encrypted_section_len < (CURVE25519_PUBKEY_LEN + DIGEST256_LEN)) { + log_info(LD_REND, "Invalid INTRODUCE2 encrypted section length " + "for service %s. Dropping cell.", + safe_str_client(service->onion_address)); + goto done; + } + + /* Check our replay cache for this introduction point. */ + if (replaycache_add_test_and_elapsed(data->replay_cache, encrypted_section, + encrypted_section_len, &elapsed)) { + log_warn(LD_REND, "Possible replay detected! An INTRODUCE2 cell with the" + "same ENCRYPTED section was seen %ld seconds ago. " + "Dropping cell.", (long int) elapsed); + goto done; + } + + /* Build the key material out of the key material found in the cell. */ + intro_keys = get_introduce2_key_material(data->auth_pk, data->enc_kp, + data->subcredential, + encrypted_section, + &data->client_pk); + if (intro_keys == NULL) { + log_info(LD_REND, "Invalid INTRODUCE2 encrypted data. Unable to " + "compute key material on circuit %u for service %s", + TO_CIRCUIT(circ)->n_circ_id, + safe_str_client(service->onion_address)); + goto done; + } + + /* Validate MAC from the cell and our computed key material. The MAC field + * in the cell is at the end of the encrypted section. */ + { + uint8_t mac[DIGEST256_LEN]; + /* The MAC field is at the very end of the ENCRYPTED section. */ + size_t mac_offset = encrypted_section_len - sizeof(mac); + /* Compute the MAC. Use the entire encoded payload with a length up to the + * ENCRYPTED section. */ + compute_introduce_mac(data->payload, + data->payload_len - encrypted_section_len, + encrypted_section, encrypted_section_len, + intro_keys->mac_key, sizeof(intro_keys->mac_key), + mac, sizeof(mac)); + if (tor_memcmp(mac, encrypted_section + mac_offset, sizeof(mac))) { + log_info(LD_REND, "Invalid MAC validation for INTRODUCE2 cell on " + "circuit %u for service %s", + TO_CIRCUIT(circ)->n_circ_id, + safe_str_client(service->onion_address)); + goto done; + } + } + + { + /* The ENCRYPTED_DATA section starts just after the CLIENT_PK. */ + const uint8_t *encrypted_data = + encrypted_section + sizeof(data->client_pk); + /* It's symmetric encryption so it's correct to use the ENCRYPTED length + * for decryption. Computes the length of ENCRYPTED_DATA meaning removing + * the CLIENT_PK and MAC length. */ + size_t encrypted_data_len = + encrypted_section_len - (sizeof(data->client_pk) + DIGEST256_LEN); + + /* This decrypts the ENCRYPTED_DATA section of the cell. */ + decrypted = decrypt_introduce2(intro_keys->enc_key, + encrypted_data, encrypted_data_len); + if (decrypted == NULL) { + log_info(LD_REND, "Unable to decrypt the ENCRYPTED section of an " + "INTRODUCE2 cell on circuit %u for service %s", + TO_CIRCUIT(circ)->n_circ_id, + safe_str_client(service->onion_address)); + goto done; + } + + /* Parse this blob into an encrypted cell structure so we can then extract + * the data we need out of it. */ + enc_cell = parse_introduce2_encrypted(decrypted, encrypted_data_len, + circ, service); + memwipe(decrypted, 0, encrypted_data_len); + if (enc_cell == NULL) { + goto done; + } + } + + /* XXX: Implement client authorization checks. */ + + /* Extract onion key and rendezvous cookie from the cell used for the + * rendezvous point circuit e2e encryption. */ + memcpy(data->onion_pk.public_key, + trn_cell_introduce_encrypted_getconstarray_onion_key(enc_cell), + CURVE25519_PUBKEY_LEN); + memcpy(data->rendezvous_cookie, + trn_cell_introduce_encrypted_getconstarray_rend_cookie(enc_cell), + sizeof(data->rendezvous_cookie)); + + /* Extract rendezvous link specifiers. */ + for (size_t idx = 0; + idx < trn_cell_introduce_encrypted_get_nspec(enc_cell); idx++) { + link_specifier_t *lspec = + trn_cell_introduce_encrypted_get_nspecs(enc_cell, idx); + smartlist_add(data->link_specifiers, hs_link_specifier_dup(lspec)); + } + + /* Success. */ + ret = 0; + log_info(LD_REND, "Valid INTRODUCE2 cell. Launching rendezvous circuit."); + + done: + if (intro_keys) { + memwipe(intro_keys, 0, sizeof(hs_ntor_intro_cell_keys_t)); + tor_free(intro_keys); + } + tor_free(decrypted); + trn_cell_introduce_encrypted_free(enc_cell); + trn_cell_introduce1_free(cell); + return ret; +} + +/* Build a RENDEZVOUS1 cell with the given rendezvous cookie and handshake + * info. The encoded cell is put in cell_out and the length of the data is + * returned. This can't fail. */ +ssize_t +hs_cell_build_rendezvous1(const uint8_t *rendezvous_cookie, + size_t rendezvous_cookie_len, + const uint8_t *rendezvous_handshake_info, + size_t rendezvous_handshake_info_len, + uint8_t *cell_out) +{ + ssize_t cell_len; + trn_cell_rendezvous1_t *cell; + + tor_assert(rendezvous_cookie); + tor_assert(rendezvous_handshake_info); + tor_assert(cell_out); + + cell = trn_cell_rendezvous1_new(); + /* Set the RENDEZVOUS_COOKIE. */ + memcpy(trn_cell_rendezvous1_getarray_rendezvous_cookie(cell), + rendezvous_cookie, rendezvous_cookie_len); + /* Set the HANDSHAKE_INFO. */ + trn_cell_rendezvous1_setlen_handshake_info(cell, + rendezvous_handshake_info_len); + memcpy(trn_cell_rendezvous1_getarray_handshake_info(cell), + rendezvous_handshake_info, rendezvous_handshake_info_len); + /* Encoding. */ + cell_len = trn_cell_rendezvous1_encode(cell_out, RELAY_PAYLOAD_SIZE, cell); + tor_assert(cell_len > 0); + + trn_cell_rendezvous1_free(cell); + return cell_len; +} + +/* Build an INTRODUCE1 cell from the given data. The encoded cell is put in + * cell_out which must be of at least size RELAY_PAYLOAD_SIZE. On success, the + * encoded length is returned else a negative value and the content of + * cell_out should be ignored. */ +ssize_t +hs_cell_build_introduce1(const hs_cell_introduce1_data_t *data, + uint8_t *cell_out) +{ + ssize_t cell_len; + trn_cell_introduce1_t *cell; + trn_cell_extension_t *ext; + + tor_assert(data); + tor_assert(cell_out); + + cell = trn_cell_introduce1_new(); + tor_assert(cell); + + /* Set extension data. None are used. */ + ext = trn_cell_extension_new(); + tor_assert(ext); + trn_cell_extension_set_num(ext, 0); + trn_cell_introduce1_set_extensions(cell, ext); + + /* Set the legacy ID field. */ + introduce1_set_legacy_id(cell, data); + + /* Set the authentication key. */ + introduce1_set_auth_key(cell, data); + + /* Set the encrypted section. This will set, encrypt and encode the + * ENCRYPTED section in the cell. After this, we'll be ready to encode. */ + introduce1_set_encrypted(cell, data); + + /* Final encoding. */ + cell_len = trn_cell_introduce1_encode(cell_out, RELAY_PAYLOAD_SIZE, cell); + + trn_cell_introduce1_free(cell); + return cell_len; +} + +/* Build an ESTABLISH_RENDEZVOUS cell from the given rendezvous_cookie. The + * encoded cell is put in cell_out which must be of at least + * RELAY_PAYLOAD_SIZE. On success, the encoded length is returned and the + * caller should clear up the content of the cell. + * + * This function can't fail. */ +ssize_t +hs_cell_build_establish_rendezvous(const uint8_t *rendezvous_cookie, + uint8_t *cell_out) +{ + tor_assert(rendezvous_cookie); + tor_assert(cell_out); + + memcpy(cell_out, rendezvous_cookie, HS_REND_COOKIE_LEN); + return HS_REND_COOKIE_LEN; +} + +/* Handle an INTRODUCE_ACK cell encoded in payload of length payload_len. + * Return the status code on success else a negative value if the cell as not + * decodable. */ +int +hs_cell_parse_introduce_ack(const uint8_t *payload, size_t payload_len) +{ + int ret = -1; + trn_cell_introduce_ack_t *cell = NULL; + + tor_assert(payload); + + /* If it is a legacy IP, rend-spec.txt specifies that a ACK is 0 byte and a + * NACK is 1 byte. We can't use the legacy function for this so we have to + * do a special case. */ + if (payload_len <= 1) { + if (payload_len == 0) { - ret = HS_CELL_INTRO_ACK_SUCCESS; ++ ret = TRUNNEL_HS_INTRO_ACK_STATUS_SUCCESS; + } else { - ret = HS_CELL_INTRO_ACK_FAILURE; ++ ret = TRUNNEL_HS_INTRO_ACK_STATUS_UNKNOWN_ID; + } + goto end; + } + + if (trn_cell_introduce_ack_parse(&cell, payload, payload_len) < 0) { + log_info(LD_REND, "Invalid INTRODUCE_ACK cell. Unable to parse it."); + goto end; + } + + ret = trn_cell_introduce_ack_get_status(cell); + + end: + trn_cell_introduce_ack_free(cell); + return ret; +} + +/* Handle a RENDEZVOUS2 cell encoded in payload of length payload_len. On + * success, handshake_info contains the data in the HANDSHAKE_INFO field, and + * 0 is returned. On error, a negative value is returned. */ +int +hs_cell_parse_rendezvous2(const uint8_t *payload, size_t payload_len, + uint8_t *handshake_info, size_t handshake_info_len) +{ + int ret = -1; + trn_cell_rendezvous2_t *cell = NULL; + + tor_assert(payload); + tor_assert(handshake_info); + + if (trn_cell_rendezvous2_parse(&cell, payload, payload_len) < 0) { + log_info(LD_REND, "Invalid RENDEZVOUS2 cell. Unable to parse it."); + goto end; + } + + /* Static size, we should never have an issue with this else we messed up + * our code flow. */ + tor_assert(trn_cell_rendezvous2_getlen_handshake_info(cell) == + handshake_info_len); + memcpy(handshake_info, + trn_cell_rendezvous2_getconstarray_handshake_info(cell), + handshake_info_len); + ret = 0; + + end: + trn_cell_rendezvous2_free(cell); + return ret; +} + +/* Clear the given INTRODUCE1 data structure data. */ +void +hs_cell_introduce1_data_clear(hs_cell_introduce1_data_t *data) +{ + if (data == NULL) { + return; + } + /* Object in this list have been moved to the cell object when building it + * so they've been freed earlier. We do that in order to avoid duplicating + * them leading to more memory and CPU time being used for nothing. */ + smartlist_free(data->link_specifiers); + /* The data object has no ownership of any members. */ + memwipe(data, 0, sizeof(hs_cell_introduce1_data_t)); +} + diff --cc src/feature/hs/hs_cell.h index abdaba4fb,000000000..9569de535 mode 100644,000000..100644 --- a/src/feature/hs/hs_cell.h +++ b/src/feature/hs/hs_cell.h @@@ -1,122 -1,0 +1,109 @@@ +/* Copyright (c) 2017-2019, The Tor Project, Inc. */ +/* See LICENSE for licensing information */ + +/** + * \file hs_cell.h + * \brief Header file containing cell data for the whole HS subsytem. + **/ + +#ifndef TOR_HS_CELL_H +#define TOR_HS_CELL_H + +#include "core/or/or.h" +#include "feature/hs/hs_service.h" + +/* An INTRODUCE1 cell requires at least this amount of bytes (see section + * 3.2.2 of the specification). Below this value, the cell must be padded. */ +#define HS_CELL_INTRODUCE1_MIN_SIZE 246 + - /* Status code of an INTRODUCE_ACK cell. */ - typedef enum { - HS_CELL_INTRO_ACK_SUCCESS = 0x0000, /* Cell relayed to service. */ - HS_CELL_INTRO_ACK_FAILURE = 0x0001, /* Service ID not recognized */ - HS_CELL_INTRO_ACK_BADFMT = 0x0002, /* Bad message format */ - HS_CELL_INTRO_ACK_NORELAY = 0x0003, /* Can't relay cell to service */ - } hs_cell_introd_ack_status_t; - - /* Onion key type found in the INTRODUCE1 cell. */ - typedef enum { - HS_CELL_ONION_KEY_TYPE_NTOR = 1, - } hs_cell_onion_key_type_t; - +/* This data structure contains data that we need to build an INTRODUCE1 cell + * used by the INTRODUCE1 build function. */ +typedef struct hs_cell_introduce1_data_t { + /* Is this a legacy introduction point? */ + unsigned int is_legacy : 1; + /* (Legacy only) The encryption key for a legacy intro point. Only set if + * is_legacy is true. */ + const crypto_pk_t *legacy_key; + /* Introduction point authentication public key. */ + const ed25519_public_key_t *auth_pk; + /* Introduction point encryption public key. */ + const curve25519_public_key_t *enc_pk; + /* Subcredentials of the service. */ + const uint8_t *subcredential; + /* Onion public key for the ntor handshake. */ + const curve25519_public_key_t *onion_pk; + /* Rendezvous cookie. */ + const uint8_t *rendezvous_cookie; + /* Public key put before the encrypted data (CLIENT_PK). */ + const curve25519_keypair_t *client_kp; + /* Rendezvous point link specifiers. */ + smartlist_t *link_specifiers; +} hs_cell_introduce1_data_t; + +/* This data structure contains data that we need to parse an INTRODUCE2 cell + * which is used by the INTRODUCE2 cell parsing function. On a successful + * parsing, the onion_pk and rendezvous_cookie will be populated with the + * computed key material from the cell data. This structure is only used during + * INTRO2 parsing and discarded after that. */ +typedef struct hs_cell_introduce2_data_t { + /*** Immutable Section: Set on structure init. ***/ + + /* Introduction point authentication public key. Pointer owned by the + introduction point object through which we received the INTRO2 cell. */ + const ed25519_public_key_t *auth_pk; + /* Introduction point encryption keypair for the ntor handshake. Pointer + owned by the introduction point object through which we received the + INTRO2 cell*/ + const curve25519_keypair_t *enc_kp; + /* Subcredentials of the service. Pointer owned by the descriptor that owns + the introduction point through which we received the INTRO2 cell. */ + const uint8_t *subcredential; + /* Payload of the received encoded cell. */ + const uint8_t *payload; + /* Size of the payload of the received encoded cell. */ + size_t payload_len; + + /*** Mutable Section: Set upon parsing INTRODUCE2 cell. ***/ + + /* Onion public key computed using the INTRODUCE2 encrypted section. */ + curve25519_public_key_t onion_pk; + /* Rendezvous cookie taken from the INTRODUCE2 encrypted section. */ + uint8_t rendezvous_cookie[REND_COOKIE_LEN]; + /* Client public key from the INTRODUCE2 encrypted section. */ + curve25519_public_key_t client_pk; + /* Link specifiers of the rendezvous point. Contains link_specifier_t. */ + smartlist_t *link_specifiers; + /* Replay cache of the introduction point. */ + replaycache_t *replay_cache; +} hs_cell_introduce2_data_t; + +/* Build cell API. */ +ssize_t hs_cell_build_establish_intro(const char *circ_nonce, + const hs_service_intro_point_t *ip, + uint8_t *cell_out); +ssize_t hs_cell_build_rendezvous1(const uint8_t *rendezvous_cookie, + size_t rendezvous_cookie_len, + const uint8_t *rendezvous_handshake_info, + size_t rendezvous_handshake_info_len, + uint8_t *cell_out); +ssize_t hs_cell_build_introduce1(const hs_cell_introduce1_data_t *data, + uint8_t *cell_out); +ssize_t hs_cell_build_establish_rendezvous(const uint8_t *rendezvous_cookie, + uint8_t *cell_out); + +/* Parse cell API. */ +ssize_t hs_cell_parse_intro_established(const uint8_t *payload, + size_t payload_len); +ssize_t hs_cell_parse_introduce2(hs_cell_introduce2_data_t *data, + const origin_circuit_t *circ, + const hs_service_t *service); +int hs_cell_parse_introduce_ack(const uint8_t *payload, size_t payload_len); +int hs_cell_parse_rendezvous2(const uint8_t *payload, size_t payload_len, + uint8_t *handshake_info, + size_t handshake_info_len); + +/* Util API. */ +void hs_cell_introduce1_data_clear(hs_cell_introduce1_data_t *data); + +#endif /* !defined(TOR_HS_CELL_H) */ + diff --cc src/feature/hs/hs_client.c index bd43ef613,000000000..2a5765aec mode 100644,000000..100644 --- a/src/feature/hs/hs_client.c +++ b/src/feature/hs/hs_client.c @@@ -1,1945 -1,0 +1,1945 @@@ +/* Copyright (c) 2016-2019, The Tor Project, Inc. */ +/* See LICENSE for licensing information */ + +/** + * \file hs_client.c + * \brief Implement next generation hidden service client functionality + **/ + +#define HS_CLIENT_PRIVATE + +#include "core/or/or.h" +#include "app/config/config.h" +#include "core/crypto/hs_ntor.h" +#include "core/mainloop/connection.h" +#include "core/or/circuitbuild.h" +#include "core/or/circuitlist.h" +#include "core/or/circuituse.h" +#include "core/or/connection_edge.h" +#include "core/or/reasons.h" +#include "feature/client/circpathbias.h" +#include "feature/dirclient/dirclient.h" +#include "feature/dircommon/directory.h" +#include "feature/hs/hs_cache.h" +#include "feature/hs/hs_cell.h" +#include "feature/hs/hs_circuit.h" +#include "feature/hs/hs_circuitmap.h" +#include "feature/hs/hs_client.h" +#include "feature/hs/hs_control.h" +#include "feature/hs/hs_descriptor.h" +#include "feature/hs/hs_ident.h" +#include "feature/nodelist/describe.h" +#include "feature/nodelist/networkstatus.h" +#include "feature/nodelist/nodelist.h" +#include "feature/nodelist/routerset.h" +#include "feature/rend/rendclient.h" +#include "lib/crypt_ops/crypto_format.h" +#include "lib/crypt_ops/crypto_rand.h" +#include "lib/crypt_ops/crypto_util.h" + +#include "core/or/cpath_build_state_st.h" +#include "feature/dircommon/dir_connection_st.h" +#include "core/or/entry_connection_st.h" +#include "core/or/extend_info_st.h" +#include "core/or/origin_circuit_st.h" + +/* Client-side authorizations for hidden services; map of service identity + * public key to hs_client_service_authorization_t *. */ +static digest256map_t *client_auths = NULL; + ++#include "trunnel/hs/cell_introduce1.h" ++ +/* Return a human-readable string for the client fetch status code. */ +static const char * +fetch_status_to_string(hs_client_fetch_status_t status) +{ + switch (status) { + case HS_CLIENT_FETCH_ERROR: + return "Internal error"; + case HS_CLIENT_FETCH_LAUNCHED: + return "Descriptor fetch launched"; + case HS_CLIENT_FETCH_HAVE_DESC: + return "Already have descriptor"; + case HS_CLIENT_FETCH_NO_HSDIRS: + return "No more HSDir available to query"; + case HS_CLIENT_FETCH_NOT_ALLOWED: + return "Fetching descriptors is not allowed"; + case HS_CLIENT_FETCH_MISSING_INFO: + return "Missing directory information"; + case HS_CLIENT_FETCH_PENDING: + return "Pending descriptor fetch"; + default: + return "(Unknown client fetch status code)"; + } +} + +/* Return true iff tor should close the SOCKS request(s) for the descriptor + * fetch that ended up with this given status code. */ +static int +fetch_status_should_close_socks(hs_client_fetch_status_t status) +{ + switch (status) { + case HS_CLIENT_FETCH_NO_HSDIRS: + /* No more HSDir to query, we can't complete the SOCKS request(s). */ + case HS_CLIENT_FETCH_ERROR: + /* The fetch triggered an internal error. */ + case HS_CLIENT_FETCH_NOT_ALLOWED: + /* Client is not allowed to fetch (FetchHidServDescriptors 0). */ + goto close; + case HS_CLIENT_FETCH_MISSING_INFO: + case HS_CLIENT_FETCH_HAVE_DESC: + case HS_CLIENT_FETCH_PENDING: + case HS_CLIENT_FETCH_LAUNCHED: + /* The rest doesn't require tor to close the SOCKS request(s). */ + goto no_close; + } + + no_close: + return 0; + close: + return 1; +} + +/* Cancel all descriptor fetches currently in progress. */ +static void +cancel_descriptor_fetches(void) +{ + smartlist_t *conns = + connection_list_by_type_state(CONN_TYPE_DIR, DIR_PURPOSE_FETCH_HSDESC); + SMARTLIST_FOREACH_BEGIN(conns, connection_t *, conn) { + const hs_ident_dir_conn_t *ident = TO_DIR_CONN(conn)->hs_ident; + if (BUG(ident == NULL)) { + /* A directory connection fetching a service descriptor can't have an + * empty hidden service identifier. */ + continue; + } + log_debug(LD_REND, "Marking for close a directory connection fetching " + "a hidden service descriptor for service %s.", + safe_str_client(ed25519_fmt(&ident->identity_pk))); + connection_mark_for_close(conn); + } SMARTLIST_FOREACH_END(conn); + + /* No ownership of the objects in this list. */ + smartlist_free(conns); + log_info(LD_REND, "Hidden service client descriptor fetches cancelled."); +} + +/* Get all connections that are waiting on a circuit and flag them back to + * waiting for a hidden service descriptor for the given service key + * service_identity_pk. */ +static void +flag_all_conn_wait_desc(const ed25519_public_key_t *service_identity_pk) +{ + tor_assert(service_identity_pk); + + smartlist_t *conns = + connection_list_by_type_state(CONN_TYPE_AP, AP_CONN_STATE_CIRCUIT_WAIT); + + SMARTLIST_FOREACH_BEGIN(conns, connection_t *, conn) { + edge_connection_t *edge_conn; + if (BUG(!CONN_IS_EDGE(conn))) { + continue; + } + edge_conn = TO_EDGE_CONN(conn); + if (edge_conn->hs_ident && + ed25519_pubkey_eq(&edge_conn->hs_ident->identity_pk, + service_identity_pk)) { + connection_ap_mark_as_waiting_for_renddesc(TO_ENTRY_CONN(conn)); + } + } SMARTLIST_FOREACH_END(conn); + + smartlist_free(conns); +} + +/* Remove tracked HSDir requests from our history for this hidden service + * identity public key. */ +static void +purge_hid_serv_request(const ed25519_public_key_t *identity_pk) +{ + char base64_blinded_pk[ED25519_BASE64_LEN + 1]; + ed25519_public_key_t blinded_pk; + + tor_assert(identity_pk); + + /* Get blinded pubkey of hidden service. It is possible that we just moved + * to a new time period meaning that we won't be able to purge the request + * from the previous time period. That is fine because they will expire at + * some point and we don't care about those anymore. */ + hs_build_blinded_pubkey(identity_pk, NULL, 0, + hs_get_time_period_num(0), &blinded_pk); + if (BUG(ed25519_public_to_base64(base64_blinded_pk, &blinded_pk) < 0)) { + return; + } + /* Purge last hidden service request from cache for this blinded key. */ + hs_purge_hid_serv_from_last_hid_serv_requests(base64_blinded_pk); +} + +/* Return true iff there is at least one pending directory descriptor request + * for the service identity_pk. */ +static int +directory_request_is_pending(const ed25519_public_key_t *identity_pk) +{ + int ret = 0; + smartlist_t *conns = + connection_list_by_type_purpose(CONN_TYPE_DIR, DIR_PURPOSE_FETCH_HSDESC); + + SMARTLIST_FOREACH_BEGIN(conns, connection_t *, conn) { + const hs_ident_dir_conn_t *ident = TO_DIR_CONN(conn)->hs_ident; + if (BUG(ident == NULL)) { + /* A directory connection fetching a service descriptor can't have an + * empty hidden service identifier. */ + continue; + } + if (!ed25519_pubkey_eq(identity_pk, &ident->identity_pk)) { + continue; + } + ret = 1; + break; + } SMARTLIST_FOREACH_END(conn); + + /* No ownership of the objects in this list. */ + smartlist_free(conns); + return ret; +} + +/* Helper function that changes the state of an entry connection to waiting + * for a circuit. For this to work properly, the connection timestamps are set + * to now and the connection is then marked as pending for a circuit. */ +static void +mark_conn_as_waiting_for_circuit(connection_t *conn, time_t now) +{ + tor_assert(conn); + + /* Because the connection can now proceed to opening circuit and ultimately + * connect to the service, reset those timestamp so the connection is + * considered "fresh" and can continue without being closed too early. */ + conn->timestamp_created = now; + conn->timestamp_last_read_allowed = now; + conn->timestamp_last_write_allowed = now; + /* Change connection's state into waiting for a circuit. */ + conn->state = AP_CONN_STATE_CIRCUIT_WAIT; + + connection_ap_mark_as_pending_circuit(TO_ENTRY_CONN(conn)); +} + +/* We failed to fetch a descriptor for the service with identity_pk + * because of status. Find all pending SOCKS connections for this + * service that are waiting on the descriptor and close them with + * reason. */ +static void +close_all_socks_conns_waiting_for_desc(const ed25519_public_key_t *identity_pk, + hs_client_fetch_status_t status, + int reason) +{ + unsigned int count = 0; + time_t now = approx_time(); + smartlist_t *conns = + connection_list_by_type_state(CONN_TYPE_AP, AP_CONN_STATE_RENDDESC_WAIT); + + SMARTLIST_FOREACH_BEGIN(conns, connection_t *, base_conn) { + entry_connection_t *entry_conn = TO_ENTRY_CONN(base_conn); + const edge_connection_t *edge_conn = ENTRY_TO_EDGE_CONN(entry_conn); + + /* Only consider the entry connections that matches the service for which + * we tried to get the descriptor */ + if (!edge_conn->hs_ident || + !ed25519_pubkey_eq(identity_pk, + &edge_conn->hs_ident->identity_pk)) { + continue; + } + assert_connection_ok(base_conn, now); + /* Unattach the entry connection which will close for the reason. */ + connection_mark_unattached_ap(entry_conn, reason); + count++; + } SMARTLIST_FOREACH_END(base_conn); + + if (count > 0) { + char onion_address[HS_SERVICE_ADDR_LEN_BASE32 + 1]; + hs_build_address(identity_pk, HS_VERSION_THREE, onion_address); + log_notice(LD_REND, "Closed %u streams for service %s.onion " + "for reason %s. Fetch status: %s.", + count, safe_str_client(onion_address), + stream_end_reason_to_string(reason), + fetch_status_to_string(status)); + } + + /* No ownership of the object(s) in this list. */ + smartlist_free(conns); +} + +/* Find all pending SOCKS connection waiting for a descriptor and retry them + * all. This is called when the directory information changed. */ +STATIC void +retry_all_socks_conn_waiting_for_desc(void) +{ + smartlist_t *conns = + connection_list_by_type_state(CONN_TYPE_AP, AP_CONN_STATE_RENDDESC_WAIT); + + SMARTLIST_FOREACH_BEGIN(conns, connection_t *, base_conn) { + hs_client_fetch_status_t status; + const edge_connection_t *edge_conn = + ENTRY_TO_EDGE_CONN(TO_ENTRY_CONN(base_conn)); + + /* Ignore non HS or non v3 connection. */ + if (edge_conn->hs_ident == NULL) { + continue; + } + /* In this loop, we will possibly try to fetch a descriptor for the + * pending connections because we just got more directory information. + * However, the refetch process can cleanup all SOCKS request to the same + * service if an internal error happens. Thus, we can end up with closed + * connections in our list. */ + if (base_conn->marked_for_close) { + continue; + } + + /* XXX: There is an optimization we could do which is that for a service + * key, we could check if we can fetch and remember that decision. */ + + /* Order a refetch in case it works this time. */ + status = hs_client_refetch_hsdesc(&edge_conn->hs_ident->identity_pk); + if (status == HS_CLIENT_FETCH_HAVE_DESC) { + /* This is a rare case where a SOCKS connection is in state waiting for + * a descriptor but we do have it in the cache. + * + * This can happen is tor comes back from suspend where it previously + * had the descriptor but the intro points were not usuable. Once it + * came back to life, the intro point failure cache was cleaned up and + * thus the descriptor became usable again leaving us in this code path. + * + * We'll mark the connection as waiting for a circuit so the descriptor + * can be retried. This is safe because a connection in state waiting + * for a descriptor can not be in the entry connection pending list. */ + mark_conn_as_waiting_for_circuit(base_conn, approx_time()); + continue; + } + /* In the case of an error, either all SOCKS connections have been + * closed or we are still missing directory information. Leave the + * connection in renddesc wait state so when we get more info, we'll be + * able to try it again. */ + } SMARTLIST_FOREACH_END(base_conn); + + /* We don't have ownership of those objects. */ + smartlist_free(conns); +} + +/* A v3 HS circuit successfully connected to the hidden service. Update the + * stream state at hs_conn_ident appropriately. */ +static void +note_connection_attempt_succeeded(const hs_ident_edge_conn_t *hs_conn_ident) +{ + tor_assert(hs_conn_ident); + + /* Remove from the hid serv cache all requests for that service so we can + * query the HSDir again later on for various reasons. */ + purge_hid_serv_request(&hs_conn_ident->identity_pk); + + /* The v2 subsystem cleans up the intro point time out flag at this stage. + * We don't try to do it here because we still need to keep intact the intro + * point state for future connections. Even though we are able to connect to + * the service, doesn't mean we should reset the timed out intro points. + * + * It is not possible to have successfully connected to an intro point + * present in our cache that was on error or timed out. Every entry in that + * cache have a 2 minutes lifetime so ultimately the intro point(s) state + * will be reset and thus possible to be retried. */ +} + +/* Given the pubkey of a hidden service in onion_identity_pk, fetch its + * descriptor by launching a dir connection to hsdir. Return a + * hs_client_fetch_status_t status code depending on how it went. */ +static hs_client_fetch_status_t +directory_launch_v3_desc_fetch(const ed25519_public_key_t *onion_identity_pk, + const routerstatus_t *hsdir) +{ + uint64_t current_time_period = hs_get_time_period_num(0); + ed25519_public_key_t blinded_pubkey; + char base64_blinded_pubkey[ED25519_BASE64_LEN + 1]; + hs_ident_dir_conn_t hs_conn_dir_ident; + int retval; + + tor_assert(hsdir); + tor_assert(onion_identity_pk); + + /* Get blinded pubkey */ + hs_build_blinded_pubkey(onion_identity_pk, NULL, 0, + current_time_period, &blinded_pubkey); + /* ...and base64 it. */ + retval = ed25519_public_to_base64(base64_blinded_pubkey, &blinded_pubkey); + if (BUG(retval < 0)) { + return HS_CLIENT_FETCH_ERROR; + } + + /* Copy onion pk to a dir_ident so that we attach it to the dir conn */ + hs_ident_dir_conn_init(onion_identity_pk, &blinded_pubkey, + &hs_conn_dir_ident); + + /* Setup directory request */ + directory_request_t *req = + directory_request_new(DIR_PURPOSE_FETCH_HSDESC); + directory_request_set_routerstatus(req, hsdir); + directory_request_set_indirection(req, DIRIND_ANONYMOUS); + directory_request_set_resource(req, base64_blinded_pubkey); + directory_request_fetch_set_hs_ident(req, &hs_conn_dir_ident); + directory_initiate_request(req); + directory_request_free(req); + + log_info(LD_REND, "Descriptor fetch request for service %s with blinded " + "key %s to directory %s", + safe_str_client(ed25519_fmt(onion_identity_pk)), + safe_str_client(base64_blinded_pubkey), + safe_str_client(routerstatus_describe(hsdir))); + + /* Fire a REQUESTED event on the control port. */ + hs_control_desc_event_requested(onion_identity_pk, base64_blinded_pubkey, + hsdir); + + /* Cleanup memory. */ + memwipe(&blinded_pubkey, 0, sizeof(blinded_pubkey)); + memwipe(base64_blinded_pubkey, 0, sizeof(base64_blinded_pubkey)); + memwipe(&hs_conn_dir_ident, 0, sizeof(hs_conn_dir_ident)); + + return HS_CLIENT_FETCH_LAUNCHED; +} + +/** Return the HSDir we should use to fetch the descriptor of the hidden + * service with identity key onion_identity_pk. */ +STATIC routerstatus_t * +pick_hsdir_v3(const ed25519_public_key_t *onion_identity_pk) +{ + int retval; + char base64_blinded_pubkey[ED25519_BASE64_LEN + 1]; + uint64_t current_time_period = hs_get_time_period_num(0); + smartlist_t *responsible_hsdirs = NULL; + ed25519_public_key_t blinded_pubkey; + routerstatus_t *hsdir_rs = NULL; + + tor_assert(onion_identity_pk); + + /* Get blinded pubkey of hidden service */ + hs_build_blinded_pubkey(onion_identity_pk, NULL, 0, + current_time_period, &blinded_pubkey); + /* ...and base64 it. */ + retval = ed25519_public_to_base64(base64_blinded_pubkey, &blinded_pubkey); + if (BUG(retval < 0)) { + return NULL; + } + + /* Get responsible hsdirs of service for this time period */ + responsible_hsdirs = smartlist_new(); + + hs_get_responsible_hsdirs(&blinded_pubkey, current_time_period, + 0, 1, responsible_hsdirs); + + log_debug(LD_REND, "Found %d responsible HSDirs and about to pick one.", + smartlist_len(responsible_hsdirs)); + + /* Pick an HSDir from the responsible ones. The ownership of + * responsible_hsdirs is given to this function so no need to free it. */ + hsdir_rs = hs_pick_hsdir(responsible_hsdirs, base64_blinded_pubkey); + + return hsdir_rs; +} + +/** Fetch a v3 descriptor using the given onion_identity_pk. + * + * On success, HS_CLIENT_FETCH_LAUNCHED is returned. Otherwise, an error from + * hs_client_fetch_status_t is returned. */ +MOCK_IMPL(STATIC hs_client_fetch_status_t, +fetch_v3_desc, (const ed25519_public_key_t *onion_identity_pk)) +{ + routerstatus_t *hsdir_rs =NULL; + + tor_assert(onion_identity_pk); + + hsdir_rs = pick_hsdir_v3(onion_identity_pk); + if (!hsdir_rs) { + log_info(LD_REND, "Couldn't pick a v3 hsdir."); + return HS_CLIENT_FETCH_NO_HSDIRS; + } + + return directory_launch_v3_desc_fetch(onion_identity_pk, hsdir_rs); +} + +/* Make sure that the given v3 origin circuit circ is a valid correct + * introduction circuit. This will BUG() on any problems and hard assert if + * the anonymity of the circuit is not ok. Return 0 on success else -1 where + * the circuit should be mark for closed immediately. */ +static int +intro_circ_is_ok(const origin_circuit_t *circ) +{ + int ret = 0; + + tor_assert(circ); + + if (BUG(TO_CIRCUIT(circ)->purpose != CIRCUIT_PURPOSE_C_INTRODUCING && + TO_CIRCUIT(circ)->purpose != CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT && + TO_CIRCUIT(circ)->purpose != CIRCUIT_PURPOSE_C_INTRODUCE_ACKED)) { + ret = -1; + } + if (BUG(circ->hs_ident == NULL)) { + ret = -1; + } + if (BUG(!hs_ident_intro_circ_is_valid(circ->hs_ident))) { + ret = -1; + } + + /* This can stop the tor daemon but we want that since if we don't have + * anonymity on this circuit, something went really wrong. */ + assert_circ_anonymity_ok(circ, get_options()); + return ret; +} + +/* Find a descriptor intro point object that matches the given ident in the + * given descriptor desc. Return NULL if not found. */ +static const hs_desc_intro_point_t * +find_desc_intro_point_by_ident(const hs_ident_circuit_t *ident, + const hs_descriptor_t *desc) +{ + const hs_desc_intro_point_t *intro_point = NULL; + + tor_assert(ident); + tor_assert(desc); + + SMARTLIST_FOREACH_BEGIN(desc->encrypted_data.intro_points, + const hs_desc_intro_point_t *, ip) { + if (ed25519_pubkey_eq(&ident->intro_auth_pk, + &ip->auth_key_cert->signed_key)) { + intro_point = ip; + break; + } + } SMARTLIST_FOREACH_END(ip); + + return intro_point; +} + +/* Find a descriptor intro point object from the descriptor object desc that + * matches the given legacy identity digest in legacy_id. Return NULL if not + * found. */ +static hs_desc_intro_point_t * +find_desc_intro_point_by_legacy_id(const char *legacy_id, + const hs_descriptor_t *desc) +{ + hs_desc_intro_point_t *ret_ip = NULL; + + tor_assert(legacy_id); + tor_assert(desc); + + /* We will go over every intro point and try to find which one is linked to + * that circuit. Those lists are small so it's not that expensive. */ + SMARTLIST_FOREACH_BEGIN(desc->encrypted_data.intro_points, + hs_desc_intro_point_t *, ip) { + SMARTLIST_FOREACH_BEGIN(ip->link_specifiers, + const hs_desc_link_specifier_t *, lspec) { + /* Not all tor node have an ed25519 identity key so we still rely on the + * legacy identity digest. */ + if (lspec->type != LS_LEGACY_ID) { + continue; + } + if (fast_memneq(legacy_id, lspec->u.legacy_id, DIGEST_LEN)) { + break; + } + /* Found it. */ + ret_ip = ip; + goto end; + } SMARTLIST_FOREACH_END(lspec); + } SMARTLIST_FOREACH_END(ip); + + end: + return ret_ip; +} + +/* Send an INTRODUCE1 cell along the intro circuit and populate the rend + * circuit identifier with the needed key material for the e2e encryption. + * Return 0 on success, -1 if there is a transient error such that an action + * has been taken to recover and -2 if there is a permanent error indicating + * that both circuits were closed. */ +static int +send_introduce1(origin_circuit_t *intro_circ, + origin_circuit_t *rend_circ) +{ + int status; + char onion_address[HS_SERVICE_ADDR_LEN_BASE32 + 1]; + const ed25519_public_key_t *service_identity_pk = NULL; + const hs_desc_intro_point_t *ip; + + tor_assert(rend_circ); + if (intro_circ_is_ok(intro_circ) < 0) { + goto perm_err; + } + + service_identity_pk = &intro_circ->hs_ident->identity_pk; + /* For logging purposes. There will be a time where the hs_ident will have a + * version number but for now there is none because it's all v3. */ + hs_build_address(service_identity_pk, HS_VERSION_THREE, onion_address); + + log_info(LD_REND, "Sending INTRODUCE1 cell to service %s on circuit %u", + safe_str_client(onion_address), TO_CIRCUIT(intro_circ)->n_circ_id); + + /* 1) Get descriptor from our cache. */ + const hs_descriptor_t *desc = + hs_cache_lookup_as_client(service_identity_pk); + if (desc == NULL || !hs_client_any_intro_points_usable(service_identity_pk, + desc)) { + log_info(LD_REND, "Request to %s %s. Trying to fetch a new descriptor.", + safe_str_client(onion_address), + (desc) ? "didn't have usable intro points" : + "didn't have a descriptor"); + hs_client_refetch_hsdesc(service_identity_pk); + /* We just triggered a refetch, make sure every connections are back + * waiting for that descriptor. */ + flag_all_conn_wait_desc(service_identity_pk); + /* We just asked for a refetch so this is a transient error. */ + goto tran_err; + } + + /* We need to find which intro point in the descriptor we are connected to + * on intro_circ. */ + ip = find_desc_intro_point_by_ident(intro_circ->hs_ident, desc); + if (BUG(ip == NULL)) { + /* If we can find a descriptor from this introduction circuit ident, we + * must have a valid intro point object. Permanent error. */ + goto perm_err; + } + + /* Send the INTRODUCE1 cell. */ + if (hs_circ_send_introduce1(intro_circ, rend_circ, ip, + desc->subcredential) < 0) { + if (TO_CIRCUIT(intro_circ)->marked_for_close) { + /* If the introduction circuit was closed, we were unable to send the + * cell for some reasons. In any case, the intro circuit has to be + * closed by the above function. We'll return a transient error so tor + * can recover and pick a new intro point. To avoid picking that same + * intro point, we'll note down the intro point failure so it doesn't + * get reused. */ + hs_cache_client_intro_state_note(service_identity_pk, + &intro_circ->hs_ident->intro_auth_pk, + INTRO_POINT_FAILURE_GENERIC); + } + /* It is also possible that the rendezvous circuit was closed due to being + * unable to use the rendezvous point node_t so in that case, we also want + * to recover and let tor pick a new one. */ + goto tran_err; + } + + /* Cell has been sent successfully. Copy the introduction point + * authentication and encryption key in the rendezvous circuit identifier so + * we can compute the ntor keys when we receive the RENDEZVOUS2 cell. */ + memcpy(&rend_circ->hs_ident->intro_enc_pk, &ip->enc_key, + sizeof(rend_circ->hs_ident->intro_enc_pk)); + ed25519_pubkey_copy(&rend_circ->hs_ident->intro_auth_pk, + &intro_circ->hs_ident->intro_auth_pk); + + /* Now, we wait for an ACK or NAK on this circuit. */ + circuit_change_purpose(TO_CIRCUIT(intro_circ), + CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT); + /* Set timestamp_dirty, because circuit_expire_building expects it to + * specify when a circuit entered the _C_INTRODUCE_ACK_WAIT state. */ + TO_CIRCUIT(intro_circ)->timestamp_dirty = time(NULL); + pathbias_count_use_attempt(intro_circ); + + /* Success. */ + status = 0; + goto end; + + perm_err: + /* Permanent error: it is possible that the intro circuit was closed prior + * because we weren't able to send the cell. Make sure we don't double close + * it which would result in a warning. */ + if (!TO_CIRCUIT(intro_circ)->marked_for_close) { + circuit_mark_for_close(TO_CIRCUIT(intro_circ), END_CIRC_REASON_INTERNAL); + } + circuit_mark_for_close(TO_CIRCUIT(rend_circ), END_CIRC_REASON_INTERNAL); + status = -2; + goto end; + + tran_err: + status = -1; + + end: + memwipe(onion_address, 0, sizeof(onion_address)); + return status; +} + +/* Using the introduction circuit circ, setup the authentication key of the + * intro point this circuit has extended to. */ +static void +setup_intro_circ_auth_key(origin_circuit_t *circ) +{ + const hs_descriptor_t *desc; + const hs_desc_intro_point_t *ip; + + tor_assert(circ); + + desc = hs_cache_lookup_as_client(&circ->hs_ident->identity_pk); + if (BUG(desc == NULL)) { + /* Opening intro circuit without the descriptor is no good... */ + goto end; + } + + /* We will go over every intro point and try to find which one is linked to + * that circuit. Those lists are small so it's not that expensive. */ + ip = find_desc_intro_point_by_legacy_id( + circ->build_state->chosen_exit->identity_digest, desc); + if (ip) { + /* We got it, copy its authentication key to the identifier. */ + ed25519_pubkey_copy(&circ->hs_ident->intro_auth_pk, + &ip->auth_key_cert->signed_key); + goto end; + } + + /* Reaching this point means we didn't find any intro point for this circuit + * which is not suppose to happen. */ + tor_assert_nonfatal_unreached(); + + end: + return; +} + +/* Called when an introduction circuit has opened. */ +static void +client_intro_circ_has_opened(origin_circuit_t *circ) +{ + tor_assert(circ); + tor_assert(TO_CIRCUIT(circ)->purpose == CIRCUIT_PURPOSE_C_INTRODUCING); + log_info(LD_REND, "Introduction circuit %u has opened. Attaching streams.", + (unsigned int) TO_CIRCUIT(circ)->n_circ_id); + + /* This is an introduction circuit so we'll attach the correct + * authentication key to the circuit identifier so it can be identified + * properly later on. */ + setup_intro_circ_auth_key(circ); + + connection_ap_attach_pending(1); +} + +/* Called when a rendezvous circuit has opened. */ +static void +client_rendezvous_circ_has_opened(origin_circuit_t *circ) +{ + tor_assert(circ); + tor_assert(TO_CIRCUIT(circ)->purpose == CIRCUIT_PURPOSE_C_ESTABLISH_REND); + + const extend_info_t *rp_ei = circ->build_state->chosen_exit; + + /* Check that we didn't accidentally choose a node that does not understand + * the v3 rendezvous protocol */ + if (rp_ei) { + const node_t *rp_node = node_get_by_id(rp_ei->identity_digest); + if (rp_node) { + if (BUG(!node_supports_v3_rendezvous_point(rp_node))) { + return; + } + } + } + + log_info(LD_REND, "Rendezvous circuit has opened to %s.", + safe_str_client(extend_info_describe(rp_ei))); + + /* Ignore returned value, nothing we can really do. On failure, the circuit + * will be marked for close. */ + hs_circ_send_establish_rendezvous(circ); + + /* Register rend circuit in circuitmap if it's still alive. */ + if (!TO_CIRCUIT(circ)->marked_for_close) { + hs_circuitmap_register_rend_circ_client_side(circ, + circ->hs_ident->rendezvous_cookie); + } +} + +/* This is an helper function that convert a descriptor intro point object ip + * to a newly allocated extend_info_t object fully initialized. Return NULL if + * we can't convert it for which chances are that we are missing or malformed + * link specifiers. */ +STATIC extend_info_t * +desc_intro_point_to_extend_info(const hs_desc_intro_point_t *ip) +{ + extend_info_t *ei; + smartlist_t *lspecs = smartlist_new(); + + tor_assert(ip); + + /* We first encode the descriptor link specifiers into the binary + * representation which is a trunnel object. */ + SMARTLIST_FOREACH_BEGIN(ip->link_specifiers, + const hs_desc_link_specifier_t *, desc_lspec) { + link_specifier_t *lspec = hs_desc_lspec_to_trunnel(desc_lspec); + smartlist_add(lspecs, lspec); + } SMARTLIST_FOREACH_END(desc_lspec); + + /* Explicitly put the direct connection option to 0 because this is client + * side and there is no such thing as a non anonymous client. */ + ei = hs_get_extend_info_from_lspecs(lspecs, &ip->onion_key, 0); + + SMARTLIST_FOREACH(lspecs, link_specifier_t *, ls, link_specifier_free(ls)); + smartlist_free(lspecs); + return ei; +} + +/* Return true iff the intro point ip for the service service_pk is usable. + * This function checks if the intro point is in the client intro state cache + * and checks at the failures. It is considered usable if: + * - No error happened (INTRO_POINT_FAILURE_GENERIC) + * - It is not flagged as timed out (INTRO_POINT_FAILURE_TIMEOUT) + * - The unreachable count is lower than + * MAX_INTRO_POINT_REACHABILITY_FAILURES (INTRO_POINT_FAILURE_UNREACHABLE) + */ +static int +intro_point_is_usable(const ed25519_public_key_t *service_pk, + const hs_desc_intro_point_t *ip) +{ + const hs_cache_intro_state_t *state; + + tor_assert(service_pk); + tor_assert(ip); + + state = hs_cache_client_intro_state_find(service_pk, + &ip->auth_key_cert->signed_key); + if (state == NULL) { + /* This means we've never encountered any problem thus usable. */ + goto usable; + } + if (state->error) { + log_info(LD_REND, "Intro point with auth key %s had an error. Not usable", + safe_str_client(ed25519_fmt(&ip->auth_key_cert->signed_key))); + goto not_usable; + } + if (state->timed_out) { + log_info(LD_REND, "Intro point with auth key %s timed out. Not usable", + safe_str_client(ed25519_fmt(&ip->auth_key_cert->signed_key))); + goto not_usable; + } + if (state->unreachable_count >= MAX_INTRO_POINT_REACHABILITY_FAILURES) { + log_info(LD_REND, "Intro point with auth key %s unreachable. Not usable", + safe_str_client(ed25519_fmt(&ip->auth_key_cert->signed_key))); + goto not_usable; + } + + usable: + return 1; + not_usable: + return 0; +} + +/* Using a descriptor desc, return a newly allocated extend_info_t object of a + * randomly picked introduction point from its list. Return NULL if none are + * usable. */ +STATIC extend_info_t * +client_get_random_intro(const ed25519_public_key_t *service_pk) +{ + extend_info_t *ei = NULL, *ei_excluded = NULL; + smartlist_t *usable_ips = NULL; + const hs_descriptor_t *desc; + const hs_desc_encrypted_data_t *enc_data; + const or_options_t *options = get_options(); + /* Calculate the onion address for logging purposes */ + char onion_address[HS_SERVICE_ADDR_LEN_BASE32 + 1]; + + tor_assert(service_pk); + + desc = hs_cache_lookup_as_client(service_pk); + /* Assume the service is v3 if the descriptor is missing. This is ok, + * because we only use the address in log messages */ + hs_build_address(service_pk, + desc ? desc->plaintext_data.version : HS_VERSION_THREE, + onion_address); + if (desc == NULL || !hs_client_any_intro_points_usable(service_pk, + desc)) { + log_info(LD_REND, "Unable to randomly select an introduction point " + "for service %s because descriptor %s. We can't connect.", + safe_str_client(onion_address), + (desc) ? "doesn't have any usable intro points" + : "is missing (assuming v3 onion address)"); + goto end; + } + + enc_data = &desc->encrypted_data; + usable_ips = smartlist_new(); + smartlist_add_all(usable_ips, enc_data->intro_points); + while (smartlist_len(usable_ips) != 0) { + int idx; + const hs_desc_intro_point_t *ip; + + /* Pick a random intro point and immediately remove it from the usable + * list so we don't pick it again if we have to iterate more. */ + idx = crypto_rand_int(smartlist_len(usable_ips)); + ip = smartlist_get(usable_ips, idx); + smartlist_del(usable_ips, idx); + + /* We need to make sure we have a usable intro points which is in a good + * state in our cache. */ + if (!intro_point_is_usable(service_pk, ip)) { + continue; + } + + /* Generate an extend info object from the intro point object. */ + ei = desc_intro_point_to_extend_info(ip); + if (ei == NULL) { + /* We can get here for instance if the intro point is a private address + * and we aren't allowed to extend to those. */ + log_info(LD_REND, "Unable to select introduction point with auth key %s " + "for service %s, because we could not extend to it.", + safe_str_client(ed25519_fmt(&ip->auth_key_cert->signed_key)), + safe_str_client(onion_address)); + continue; + } + + /* Test the pick against ExcludeNodes. */ + if (routerset_contains_extendinfo(options->ExcludeNodes, ei)) { + /* If this pick is in the ExcludeNodes list, we keep its reference so if + * we ever end up not being able to pick anything else and StrictNodes is + * unset, we'll use it. */ + if (ei_excluded) { + /* If something was already here free it. After the loop is gone we + * will examine the last excluded intro point, and that's fine since + * that's random anyway */ + extend_info_free(ei_excluded); + } + ei_excluded = ei; + continue; + } + + /* Good pick! Let's go with this. */ + goto end; + } + + /* Reaching this point means a couple of things. Either we can't use any of + * the intro point listed because the IP address can't be extended to or it + * is listed in the ExcludeNodes list. In the later case, if StrictNodes is + * set, we are forced to not use anything. */ + ei = ei_excluded; + if (options->StrictNodes) { + log_warn(LD_REND, "Every introduction point for service %s is in the " + "ExcludeNodes set and StrictNodes is set. We can't connect.", + safe_str_client(onion_address)); + extend_info_free(ei); + ei = NULL; + } else { + log_fn(LOG_PROTOCOL_WARN, LD_REND, "Every introduction point for service " + "%s is unusable or we can't extend to it. We can't connect.", + safe_str_client(onion_address)); + } + + end: + smartlist_free(usable_ips); + memwipe(onion_address, 0, sizeof(onion_address)); + return ei; +} + +/* For this introduction circuit, we'll look at if we have any usable + * introduction point left for this service. If so, we'll use the circuit to + * re-extend to a new intro point. Else, we'll close the circuit and its + * corresponding rendezvous circuit. Return 0 if we are re-extending else -1 + * if we are closing the circuits. + * + * This is called when getting an INTRODUCE_ACK cell with a NACK. */ +static int +close_or_reextend_intro_circ(origin_circuit_t *intro_circ) +{ + int ret = -1; + const hs_descriptor_t *desc; + origin_circuit_t *rend_circ; + + tor_assert(intro_circ); + + desc = hs_cache_lookup_as_client(&intro_circ->hs_ident->identity_pk); + if (BUG(desc == NULL)) { + /* We can't continue without a descriptor. */ + goto close; + } + /* We still have the descriptor, great! Let's try to see if we can + * re-extend by looking up if there are any usable intro points. */ + if (!hs_client_any_intro_points_usable(&intro_circ->hs_ident->identity_pk, + desc)) { + goto close; + } + /* Try to re-extend now. */ + if (hs_client_reextend_intro_circuit(intro_circ) < 0) { + goto close; + } + /* Success on re-extending. Don't return an error. */ + ret = 0; + goto end; + + close: + /* Change the intro circuit purpose before so we don't report an intro point + * failure again triggering an extra descriptor fetch. The circuit can + * already be closed on failure to re-extend. */ + if (!TO_CIRCUIT(intro_circ)->marked_for_close) { + circuit_change_purpose(TO_CIRCUIT(intro_circ), + CIRCUIT_PURPOSE_C_INTRODUCE_ACKED); + circuit_mark_for_close(TO_CIRCUIT(intro_circ), END_CIRC_REASON_FINISHED); + } + /* Close the related rendezvous circuit. */ + rend_circ = hs_circuitmap_get_rend_circ_client_side( + intro_circ->hs_ident->rendezvous_cookie); + /* The rendezvous circuit might have collapsed while the INTRODUCE_ACK was + * inflight so we can't expect one every time. */ + if (rend_circ) { + circuit_mark_for_close(TO_CIRCUIT(rend_circ), END_CIRC_REASON_FINISHED); + } + + end: + return ret; +} + +/* Called when we get an INTRODUCE_ACK success status code. Do the appropriate + * actions for the rendezvous point and finally close intro_circ. */ +static void +handle_introduce_ack_success(origin_circuit_t *intro_circ) +{ + origin_circuit_t *rend_circ = NULL; + + tor_assert(intro_circ); + + log_info(LD_REND, "Received INTRODUCE_ACK ack! Informing rendezvous"); + + /* Get the rendezvous circuit for this rendezvous cookie. */ + uint8_t *rendezvous_cookie = intro_circ->hs_ident->rendezvous_cookie; + rend_circ = + hs_circuitmap_get_established_rend_circ_client_side(rendezvous_cookie); + if (rend_circ == NULL) { + log_warn(LD_REND, "Can't find any rendezvous circuit. Stopping"); + goto end; + } + + assert_circ_anonymity_ok(rend_circ, get_options()); + + /* It is possible to get a RENDEZVOUS2 cell before the INTRODUCE_ACK which + * means that the circuit will be joined and already transmitting data. In + * that case, simply skip the purpose change and close the intro circuit + * like it should be. */ + if (TO_CIRCUIT(rend_circ)->purpose == CIRCUIT_PURPOSE_C_REND_JOINED) { + goto end; + } + circuit_change_purpose(TO_CIRCUIT(rend_circ), + CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED); + /* Set timestamp_dirty, because circuit_expire_building expects it to + * specify when a circuit entered the + * CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED state. */ + TO_CIRCUIT(rend_circ)->timestamp_dirty = time(NULL); + + end: + /* We don't need the intro circuit anymore. It did what it had to do! */ + circuit_change_purpose(TO_CIRCUIT(intro_circ), + CIRCUIT_PURPOSE_C_INTRODUCE_ACKED); + circuit_mark_for_close(TO_CIRCUIT(intro_circ), END_CIRC_REASON_FINISHED); + + /* XXX: Close pending intro circuits we might have in parallel. */ + return; +} + +/* Called when we get an INTRODUCE_ACK failure status code. Depending on our + * failure cache status, either close the circuit or re-extend to a new + * introduction point. */ +static void +handle_introduce_ack_bad(origin_circuit_t *circ, int status) +{ + tor_assert(circ); + + log_info(LD_REND, "Received INTRODUCE_ACK nack by %s. Reason: %u", + safe_str_client(extend_info_describe(circ->build_state->chosen_exit)), + status); + + /* It's a NAK. The introduction point didn't relay our request. */ + circuit_change_purpose(TO_CIRCUIT(circ), CIRCUIT_PURPOSE_C_INTRODUCING); + + /* Note down this failure in the intro point failure cache. Depending on how + * many times we've tried this intro point, close it or reextend. */ + hs_cache_client_intro_state_note(&circ->hs_ident->identity_pk, + &circ->hs_ident->intro_auth_pk, + INTRO_POINT_FAILURE_GENERIC); +} + +/* Called when we get an INTRODUCE_ACK on the intro circuit circ. The encoded + * cell is in payload of length payload_len. Return 0 on success else a + * negative value. The circuit is either close or reuse to re-extend to a new + * introduction point. */ +static int +handle_introduce_ack(origin_circuit_t *circ, const uint8_t *payload, + size_t payload_len) +{ + int status, ret = -1; + + tor_assert(circ); + tor_assert(circ->build_state); + tor_assert(circ->build_state->chosen_exit); + assert_circ_anonymity_ok(circ, get_options()); + tor_assert(payload); + + status = hs_cell_parse_introduce_ack(payload, payload_len); + switch (status) { - case HS_CELL_INTRO_ACK_SUCCESS: ++ case TRUNNEL_HS_INTRO_ACK_STATUS_SUCCESS: + ret = 0; + handle_introduce_ack_success(circ); + goto end; - case HS_CELL_INTRO_ACK_FAILURE: - case HS_CELL_INTRO_ACK_BADFMT: - case HS_CELL_INTRO_ACK_NORELAY: ++ case TRUNNEL_HS_INTRO_ACK_STATUS_UNKNOWN_ID: ++ case TRUNNEL_HS_INTRO_ACK_STATUS_BAD_FORMAT: ++ /* It is possible that the intro point can send us an unknown status code ++ * for the NACK that we do not know about like a new code for instance. ++ * Just fallthrough so we can note down the NACK and re-extend. */ ++ default: + handle_introduce_ack_bad(circ, status); + /* We are going to see if we have to close the circuits (IP and RP) or we + * can re-extend to a new intro point. */ + ret = close_or_reextend_intro_circ(circ); + break; - default: - log_info(LD_PROTOCOL, "Unknown INTRODUCE_ACK status code %u from %s", - status, - safe_str_client(extend_info_describe(circ->build_state->chosen_exit))); - break; + } + + end: + return ret; +} + +/* Called when we get a RENDEZVOUS2 cell on the rendezvous circuit circ. The + * encoded cell is in payload of length payload_len. Return 0 on success or a + * negative value on error. On error, the circuit is marked for close. */ +STATIC int +handle_rendezvous2(origin_circuit_t *circ, const uint8_t *payload, + size_t payload_len) +{ + int ret = -1; + curve25519_public_key_t server_pk; + uint8_t auth_mac[DIGEST256_LEN] = {0}; + uint8_t handshake_info[CURVE25519_PUBKEY_LEN + sizeof(auth_mac)] = {0}; + hs_ntor_rend_cell_keys_t keys; + const hs_ident_circuit_t *ident; + + tor_assert(circ); + tor_assert(payload); + + /* Make things easier. */ + ident = circ->hs_ident; + tor_assert(ident); + + if (hs_cell_parse_rendezvous2(payload, payload_len, handshake_info, + sizeof(handshake_info)) < 0) { + goto err; + } + /* Get from the handshake info the SERVER_PK and AUTH_MAC. */ + memcpy(&server_pk, handshake_info, CURVE25519_PUBKEY_LEN); + memcpy(auth_mac, handshake_info + CURVE25519_PUBKEY_LEN, sizeof(auth_mac)); + + /* Generate the handshake info. */ + if (hs_ntor_client_get_rendezvous1_keys(&ident->intro_auth_pk, + &ident->rendezvous_client_kp, + &ident->intro_enc_pk, &server_pk, + &keys) < 0) { + log_info(LD_REND, "Unable to compute the rendezvous keys."); + goto err; + } + + /* Critical check, make sure that the MAC matches what we got with what we + * computed just above. */ + if (!hs_ntor_client_rendezvous2_mac_is_good(&keys, auth_mac)) { + log_info(LD_REND, "Invalid MAC in RENDEZVOUS2. Rejecting cell."); + goto err; + } + + /* Setup the e2e encryption on the circuit and finalize its state. */ + if (hs_circuit_setup_e2e_rend_circ(circ, keys.ntor_key_seed, + sizeof(keys.ntor_key_seed), 0) < 0) { + log_info(LD_REND, "Unable to setup the e2e encryption."); + goto err; + } + /* Success. Hidden service connection finalized! */ + ret = 0; + goto end; + + err: + circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_TORPROTOCOL); + end: + memwipe(&keys, 0, sizeof(keys)); + return ret; +} + +/* Return true iff the client can fetch a descriptor for this service public + * identity key and status_out if not NULL is untouched. If the client can + * _not_ fetch the descriptor and if status_out is not NULL, it is set with + * the fetch status code. */ +static unsigned int +can_client_refetch_desc(const ed25519_public_key_t *identity_pk, + hs_client_fetch_status_t *status_out) +{ + hs_client_fetch_status_t status; + + tor_assert(identity_pk); + + /* Are we configured to fetch descriptors? */ + if (!get_options()->FetchHidServDescriptors) { + log_warn(LD_REND, "We received an onion address for a hidden service " + "descriptor but we are configured to not fetch."); + status = HS_CLIENT_FETCH_NOT_ALLOWED; + goto cannot; + } + + /* Without a live consensus we can't do any client actions. It is needed to + * compute the hashring for a service. */ + if (!networkstatus_get_live_consensus(approx_time())) { + log_info(LD_REND, "Can't fetch descriptor for service %s because we " + "are missing a live consensus. Stalling connection.", + safe_str_client(ed25519_fmt(identity_pk))); + status = HS_CLIENT_FETCH_MISSING_INFO; + goto cannot; + } + + if (!router_have_minimum_dir_info()) { + log_info(LD_REND, "Can't fetch descriptor for service %s because we " + "dont have enough descriptors. Stalling connection.", + safe_str_client(ed25519_fmt(identity_pk))); + status = HS_CLIENT_FETCH_MISSING_INFO; + goto cannot; + } + + /* Check if fetching a desc for this HS is useful to us right now */ + { + const hs_descriptor_t *cached_desc = NULL; + cached_desc = hs_cache_lookup_as_client(identity_pk); + if (cached_desc && hs_client_any_intro_points_usable(identity_pk, + cached_desc)) { + log_info(LD_GENERAL, "We would fetch a v3 hidden service descriptor " + "but we already have a usable descriptor."); + status = HS_CLIENT_FETCH_HAVE_DESC; + goto cannot; + } + } + + /* Don't try to refetch while we have a pending request for it. */ + if (directory_request_is_pending(identity_pk)) { + log_info(LD_REND, "Already a pending directory request. Waiting on it."); + status = HS_CLIENT_FETCH_PENDING; + goto cannot; + } + + /* Yes, client can fetch! */ + return 1; + cannot: + if (status_out) { + *status_out = status; + } + return 0; +} + +/* Return the client auth in the map using the service identity public key. + * Return NULL if it does not exist in the map. */ +static hs_client_service_authorization_t * +find_client_auth(const ed25519_public_key_t *service_identity_pk) +{ + /* If the map is not allocated, we can assume that we do not have any client + * auth information. */ + if (!client_auths) { + return NULL; + } + return digest256map_get(client_auths, service_identity_pk->pubkey); +} + +/* ========== */ +/* Public API */ +/* ========== */ + +/** A circuit just finished connecting to a hidden service that the stream + * conn has been waiting for. Let the HS subsystem know about this. */ +void +hs_client_note_connection_attempt_succeeded(const edge_connection_t *conn) +{ + tor_assert(connection_edge_is_rendezvous_stream(conn)); + + if (BUG(conn->rend_data && conn->hs_ident)) { + log_warn(LD_BUG, "Stream had both rend_data and hs_ident..." + "Prioritizing hs_ident"); + } + + if (conn->hs_ident) { /* It's v3: pass it to the prop224 handler */ + note_connection_attempt_succeeded(conn->hs_ident); + return; + } else if (conn->rend_data) { /* It's v2: pass it to the legacy handler */ + rend_client_note_connection_attempt_ended(conn->rend_data); + return; + } +} + +/* With the given encoded descriptor in desc_str and the service key in + * service_identity_pk, decode the descriptor and set the desc pointer with a + * newly allocated descriptor object. + * + * Return 0 on success else a negative value and desc is set to NULL. */ +int +hs_client_decode_descriptor(const char *desc_str, + const ed25519_public_key_t *service_identity_pk, + hs_descriptor_t **desc) +{ + int ret; + uint8_t subcredential[DIGEST256_LEN]; + ed25519_public_key_t blinded_pubkey; + hs_client_service_authorization_t *client_auth = NULL; + curve25519_secret_key_t *client_auht_sk = NULL; + + tor_assert(desc_str); + tor_assert(service_identity_pk); + tor_assert(desc); + + /* Check if we have a client authorization for this service in the map. */ + client_auth = find_client_auth(service_identity_pk); + if (client_auth) { + client_auht_sk = &client_auth->enc_seckey; + } + + /* Create subcredential for this HS so that we can decrypt */ + { + uint64_t current_time_period = hs_get_time_period_num(0); + hs_build_blinded_pubkey(service_identity_pk, NULL, 0, current_time_period, + &blinded_pubkey); + hs_get_subcredential(service_identity_pk, &blinded_pubkey, subcredential); + } + + /* Parse descriptor */ + ret = hs_desc_decode_descriptor(desc_str, subcredential, + client_auht_sk, desc); + memwipe(subcredential, 0, sizeof(subcredential)); + if (ret < 0) { + goto err; + } + + /* Make sure the descriptor signing key cross certifies with the computed + * blinded key. Without this validation, anyone knowing the subcredential + * and onion address can forge a descriptor. */ + tor_cert_t *cert = (*desc)->plaintext_data.signing_key_cert; + if (tor_cert_checksig(cert, + &blinded_pubkey, approx_time()) < 0) { + log_warn(LD_GENERAL, "Descriptor signing key certificate signature " + "doesn't validate with computed blinded key: %s", + tor_cert_describe_signature_status(cert)); + goto err; + } + + return 0; + err: + return -1; +} + +/* Return true iff there are at least one usable intro point in the service + * descriptor desc. */ +int +hs_client_any_intro_points_usable(const ed25519_public_key_t *service_pk, + const hs_descriptor_t *desc) +{ + tor_assert(service_pk); + tor_assert(desc); + + SMARTLIST_FOREACH_BEGIN(desc->encrypted_data.intro_points, + const hs_desc_intro_point_t *, ip) { + if (intro_point_is_usable(service_pk, ip)) { + goto usable; + } + } SMARTLIST_FOREACH_END(ip); + + return 0; + usable: + return 1; +} + +/** Launch a connection to a hidden service directory to fetch a hidden + * service descriptor using identity_pk to get the necessary keys. + * + * A hs_client_fetch_status_t code is returned. */ +int +hs_client_refetch_hsdesc(const ed25519_public_key_t *identity_pk) +{ + hs_client_fetch_status_t status; + + tor_assert(identity_pk); + + if (!can_client_refetch_desc(identity_pk, &status)) { + return status; + } + + /* Try to fetch the desc and if we encounter an unrecoverable error, mark + * the desc as unavailable for now. */ + status = fetch_v3_desc(identity_pk); + if (fetch_status_should_close_socks(status)) { + close_all_socks_conns_waiting_for_desc(identity_pk, status, + END_STREAM_REASON_RESOLVEFAILED); + /* Remove HSDir fetch attempts so that we can retry later if the user + * wants us to regardless of if we closed any connections. */ + purge_hid_serv_request(identity_pk); + } + return status; +} + +/* This is called when we are trying to attach an AP connection to these + * hidden service circuits from connection_ap_handshake_attach_circuit(). + * Return 0 on success, -1 for a transient error that is actions were + * triggered to recover or -2 for a permenent error where both circuits will + * marked for close. + * + * The following supports every hidden service version. */ +int +hs_client_send_introduce1(origin_circuit_t *intro_circ, + origin_circuit_t *rend_circ) +{ + return (intro_circ->hs_ident) ? send_introduce1(intro_circ, rend_circ) : + rend_client_send_introduction(intro_circ, + rend_circ); +} + +/* Called when the client circuit circ has been established. It can be either + * an introduction or rendezvous circuit. This function handles all hidden + * service versions. */ +void +hs_client_circuit_has_opened(origin_circuit_t *circ) +{ + tor_assert(circ); + + /* Handle both version. v2 uses rend_data and v3 uses the hs circuit + * identifier hs_ident. Can't be both. */ + switch (TO_CIRCUIT(circ)->purpose) { + case CIRCUIT_PURPOSE_C_INTRODUCING: + if (circ->hs_ident) { + client_intro_circ_has_opened(circ); + } else { + rend_client_introcirc_has_opened(circ); + } + break; + case CIRCUIT_PURPOSE_C_ESTABLISH_REND: + if (circ->hs_ident) { + client_rendezvous_circ_has_opened(circ); + } else { + rend_client_rendcirc_has_opened(circ); + } + break; + default: + tor_assert_nonfatal_unreached(); + } +} + +/* Called when we receive a RENDEZVOUS_ESTABLISHED cell. Change the state of + * the circuit to CIRCUIT_PURPOSE_C_REND_READY. Return 0 on success else a + * negative value and the circuit marked for close. */ +int +hs_client_receive_rendezvous_acked(origin_circuit_t *circ, + const uint8_t *payload, size_t payload_len) +{ + tor_assert(circ); + tor_assert(payload); + + (void) payload_len; + + if (TO_CIRCUIT(circ)->purpose != CIRCUIT_PURPOSE_C_ESTABLISH_REND) { + log_warn(LD_PROTOCOL, "Got a RENDEZVOUS_ESTABLISHED but we were not " + "expecting one. Closing circuit."); + goto err; + } + + log_info(LD_REND, "Received an RENDEZVOUS_ESTABLISHED. This circuit is " + "now ready for rendezvous."); + circuit_change_purpose(TO_CIRCUIT(circ), CIRCUIT_PURPOSE_C_REND_READY); + + /* Set timestamp_dirty, because circuit_expire_building expects it to + * specify when a circuit entered the _C_REND_READY state. */ + TO_CIRCUIT(circ)->timestamp_dirty = time(NULL); + + /* From a path bias point of view, this circuit is now successfully used. + * Waiting any longer opens us up to attacks from malicious hidden services. + * They could induce the client to attempt to connect to their hidden + * service and never reply to the client's rend requests */ + pathbias_mark_use_success(circ); + + /* If we already have the introduction circuit built, make sure we send + * the INTRODUCE cell _now_ */ + connection_ap_attach_pending(1); + + return 0; + err: + circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_TORPROTOCOL); + return -1; +} + +#define client_service_authorization_free(auth) \ + FREE_AND_NULL(hs_client_service_authorization_t, \ + client_service_authorization_free_, (auth)) + +static void +client_service_authorization_free_(hs_client_service_authorization_t *auth) +{ + if (auth) { + memwipe(auth, 0, sizeof(*auth)); + } + tor_free(auth); +} + +/** Helper for digest256map_free. */ +static void +client_service_authorization_free_void(void *auth) +{ + client_service_authorization_free_(auth); +} + +static void +client_service_authorization_free_all(void) +{ + if (!client_auths) { + return; + } + digest256map_free(client_auths, client_service_authorization_free_void); +} + +/* Check if the auth key file name is valid or not. Return 1 if valid, + * otherwise return 0. */ +STATIC int +auth_key_filename_is_valid(const char *filename) +{ + int ret = 1; + const char *valid_extension = ".auth_private"; + + tor_assert(filename); + + /* The length of the filename must be greater than the length of the + * extension and the valid extension must be at the end of filename. */ + if (!strcmpend(filename, valid_extension) && + strlen(filename) != strlen(valid_extension)) { + ret = 1; + } else { + ret = 0; + } + + return ret; +} + +STATIC hs_client_service_authorization_t * +parse_auth_file_content(const char *client_key_str) +{ + char *onion_address = NULL; + char *auth_type = NULL; + char *key_type = NULL; + char *seckey_b32 = NULL; + hs_client_service_authorization_t *auth = NULL; + smartlist_t *fields = smartlist_new(); + + tor_assert(client_key_str); + + smartlist_split_string(fields, client_key_str, ":", + SPLIT_SKIP_SPACE, 0); + /* Wrong number of fields. */ + if (smartlist_len(fields) != 4) { + goto err; + } + + onion_address = smartlist_get(fields, 0); + auth_type = smartlist_get(fields, 1); + key_type = smartlist_get(fields, 2); + seckey_b32 = smartlist_get(fields, 3); + + /* Currently, the only supported auth type is "descriptor" and the only + * supported key type is "x25519". */ + if (strcmp(auth_type, "descriptor") || strcmp(key_type, "x25519")) { + goto err; + } + + if (strlen(seckey_b32) != BASE32_NOPAD_LEN(CURVE25519_PUBKEY_LEN)) { + log_warn(LD_REND, "Client authorization encoded base32 private key " + "length is invalid: %s", seckey_b32); + goto err; + } + + auth = tor_malloc_zero(sizeof(hs_client_service_authorization_t)); + if (base32_decode((char *) auth->enc_seckey.secret_key, + sizeof(auth->enc_seckey.secret_key), + seckey_b32, strlen(seckey_b32)) < 0) { + goto err; + } + strncpy(auth->onion_address, onion_address, HS_SERVICE_ADDR_LEN_BASE32); + + /* Success. */ + goto done; + + err: + client_service_authorization_free(auth); + done: + /* It is also a good idea to wipe the private key. */ + if (seckey_b32) { + memwipe(seckey_b32, 0, strlen(seckey_b32)); + } + tor_assert(fields); + SMARTLIST_FOREACH(fields, char *, s, tor_free(s)); + smartlist_free(fields); + return auth; +} + +/* From a set of options, setup every client authorization detail + * found. Return 0 on success or -1 on failure. If validate_only + * is set, parse, warn and return as normal, but don't actually change + * the configuration. */ +int +hs_config_client_authorization(const or_options_t *options, + int validate_only) +{ + int ret = -1; + digest256map_t *auths = digest256map_new(); + char *key_dir = NULL; + smartlist_t *file_list = NULL; + char *client_key_str = NULL; + char *client_key_file_path = NULL; + + tor_assert(options); + + /* There is no client auth configured. We can just silently ignore this + * function. */ + if (!options->ClientOnionAuthDir) { + ret = 0; + goto end; + } + + key_dir = tor_strdup(options->ClientOnionAuthDir); + + /* Make sure the directory exists and is private enough. */ + if (check_private_dir(key_dir, 0, options->User) < 0) { + goto end; + } + + file_list = tor_listdir(key_dir); + if (file_list == NULL) { + log_warn(LD_REND, "Client authorization key directory %s can't be listed.", + key_dir); + goto end; + } + + SMARTLIST_FOREACH_BEGIN(file_list, char *, filename) { + + hs_client_service_authorization_t *auth = NULL; + ed25519_public_key_t identity_pk; + log_info(LD_REND, "Loading a client authorization key file %s...", + filename); + + if (!auth_key_filename_is_valid(filename)) { + log_notice(LD_REND, "Client authorization unrecognized filename %s. " + "File must end in .auth_private. Ignoring.", + filename); + continue; + } + + /* Create a full path for a file. */ + client_key_file_path = hs_path_from_filename(key_dir, filename); + client_key_str = read_file_to_str(client_key_file_path, 0, NULL); + /* Free the file path immediately after using it. */ + tor_free(client_key_file_path); + + /* If we cannot read the file, continue with the next file. */ + if (!client_key_str) { + log_warn(LD_REND, "The file %s cannot be read.", filename); + continue; + } + + auth = parse_auth_file_content(client_key_str); + /* Free immediately after using it. */ + tor_free(client_key_str); + + if (auth) { + /* Parse the onion address to get an identity public key and use it + * as a key of global map in the future. */ + if (hs_parse_address(auth->onion_address, &identity_pk, + NULL, NULL) < 0) { + log_warn(LD_REND, "The onion address \"%s\" is invalid in " + "file %s", filename, auth->onion_address); + client_service_authorization_free(auth); + continue; + } + + if (digest256map_get(auths, identity_pk.pubkey)) { + log_warn(LD_REND, "Duplicate authorization for the same hidden " + "service address %s.", + safe_str_client_opts(options, auth->onion_address)); + client_service_authorization_free(auth); + goto end; + } + + digest256map_set(auths, identity_pk.pubkey, auth); + log_info(LD_REND, "Loaded a client authorization key file %s.", + filename); + } + } SMARTLIST_FOREACH_END(filename); + + /* Success. */ + ret = 0; + + end: + tor_free(key_dir); + tor_free(client_key_str); + tor_free(client_key_file_path); + if (file_list) { + SMARTLIST_FOREACH(file_list, char *, s, tor_free(s)); + smartlist_free(file_list); + } + + if (!validate_only && ret == 0) { + client_service_authorization_free_all(); + client_auths = auths; + } else { + digest256map_free(auths, client_service_authorization_free_void); + } + + return ret; +} + +/* This is called when a descriptor has arrived following a fetch request and + * has been stored in the client cache. Every entry connection that matches + * the service identity key in the ident will get attached to the hidden + * service circuit. */ +void +hs_client_desc_has_arrived(const hs_ident_dir_conn_t *ident) +{ + time_t now = time(NULL); + smartlist_t *conns = NULL; + + tor_assert(ident); + + conns = connection_list_by_type_state(CONN_TYPE_AP, + AP_CONN_STATE_RENDDESC_WAIT); + SMARTLIST_FOREACH_BEGIN(conns, connection_t *, base_conn) { + const hs_descriptor_t *desc; + entry_connection_t *entry_conn = TO_ENTRY_CONN(base_conn); + const edge_connection_t *edge_conn = ENTRY_TO_EDGE_CONN(entry_conn); + + /* Only consider the entry connections that matches the service for which + * we just fetched its descriptor. */ + if (!edge_conn->hs_ident || + !ed25519_pubkey_eq(&ident->identity_pk, + &edge_conn->hs_ident->identity_pk)) { + continue; + } + assert_connection_ok(base_conn, now); + + /* We were just called because we stored the descriptor for this service + * so not finding a descriptor means we have a bigger problem. */ + desc = hs_cache_lookup_as_client(&ident->identity_pk); + if (BUG(desc == NULL)) { + goto end; + } + + if (!hs_client_any_intro_points_usable(&ident->identity_pk, desc)) { + log_info(LD_REND, "Hidden service descriptor is unusable. " + "Closing streams."); + connection_mark_unattached_ap(entry_conn, + END_STREAM_REASON_RESOLVEFAILED); + /* We are unable to use the descriptor so remove the directory request + * from the cache so the next connection can try again. */ + note_connection_attempt_succeeded(edge_conn->hs_ident); + continue; + } + + log_info(LD_REND, "Descriptor has arrived. Launching circuits."); + + /* Mark connection as waiting for a circuit since we do have a usable + * descriptor now. */ + mark_conn_as_waiting_for_circuit(base_conn, now); + } SMARTLIST_FOREACH_END(base_conn); + + end: + /* We don't have ownership of the objects in this list. */ + smartlist_free(conns); +} + +/* Return a newly allocated extend_info_t for a randomly chosen introduction + * point for the given edge connection identifier ident. Return NULL if we + * can't pick any usable introduction points. */ +extend_info_t * +hs_client_get_random_intro_from_edge(const edge_connection_t *edge_conn) +{ + tor_assert(edge_conn); + + return (edge_conn->hs_ident) ? + client_get_random_intro(&edge_conn->hs_ident->identity_pk) : + rend_client_get_random_intro(edge_conn->rend_data); +} + +/* Called when get an INTRODUCE_ACK cell on the introduction circuit circ. + * Return 0 on success else a negative value is returned. The circuit will be + * closed or reuse to extend again to another intro point. */ +int +hs_client_receive_introduce_ack(origin_circuit_t *circ, + const uint8_t *payload, size_t payload_len) +{ + int ret = -1; + + tor_assert(circ); + tor_assert(payload); + + if (TO_CIRCUIT(circ)->purpose != CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT) { + log_warn(LD_PROTOCOL, "Unexpected INTRODUCE_ACK on circuit %u.", + (unsigned int) TO_CIRCUIT(circ)->n_circ_id); + circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_TORPROTOCOL); + goto end; + } + + ret = (circ->hs_ident) ? handle_introduce_ack(circ, payload, payload_len) : + rend_client_introduction_acked(circ, payload, + payload_len); + /* For path bias: This circuit was used successfully. NACK or ACK counts. */ + pathbias_mark_use_success(circ); + + end: + return ret; +} + +/* Called when get a RENDEZVOUS2 cell on the rendezvous circuit circ. Return + * 0 on success else a negative value is returned. The circuit will be closed + * on error. */ +int +hs_client_receive_rendezvous2(origin_circuit_t *circ, + const uint8_t *payload, size_t payload_len) +{ + int ret = -1; + + tor_assert(circ); + tor_assert(payload); + + /* Circuit can possibly be in both state because we could receive a + * RENDEZVOUS2 cell before the INTRODUCE_ACK has been received. */ + if (TO_CIRCUIT(circ)->purpose != CIRCUIT_PURPOSE_C_REND_READY && + TO_CIRCUIT(circ)->purpose != CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED) { + log_warn(LD_PROTOCOL, "Unexpected RENDEZVOUS2 cell on circuit %u. " + "Closing circuit.", + (unsigned int) TO_CIRCUIT(circ)->n_circ_id); + circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_TORPROTOCOL); + goto end; + } + + log_info(LD_REND, "Got RENDEZVOUS2 cell from hidden service on circuit %u.", + TO_CIRCUIT(circ)->n_circ_id); + + ret = (circ->hs_ident) ? handle_rendezvous2(circ, payload, payload_len) : + rend_client_receive_rendezvous(circ, payload, + payload_len); + end: + return ret; +} + +/* Extend the introduction circuit circ to another valid introduction point + * for the hidden service it is trying to connect to, or mark it and launch a + * new circuit if we can't extend it. Return 0 on success or possible + * success. Return -1 and mark the introduction circuit for close on permanent + * failure. + * + * On failure, the caller is responsible for marking the associated rendezvous + * circuit for close. */ +int +hs_client_reextend_intro_circuit(origin_circuit_t *circ) +{ + int ret = -1; + extend_info_t *ei; + + tor_assert(circ); + + ei = (circ->hs_ident) ? + client_get_random_intro(&circ->hs_ident->identity_pk) : + rend_client_get_random_intro(circ->rend_data); + if (ei == NULL) { + log_warn(LD_REND, "No usable introduction points left. Closing."); + circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_INTERNAL); + goto end; + } + + if (circ->remaining_relay_early_cells) { + log_info(LD_REND, "Re-extending circ %u, this time to %s.", + (unsigned int) TO_CIRCUIT(circ)->n_circ_id, + safe_str_client(extend_info_describe(ei))); + ret = circuit_extend_to_new_exit(circ, ei); + if (ret == 0) { + /* We were able to extend so update the timestamp so we avoid expiring + * this circuit too early. The intro circuit is short live so the + * linkability issue is minimized, we just need the circuit to hold a + * bit longer so we can introduce. */ + TO_CIRCUIT(circ)->timestamp_dirty = time(NULL); + } + } else { + log_info(LD_REND, "Closing intro circ %u (out of RELAY_EARLY cells).", + (unsigned int) TO_CIRCUIT(circ)->n_circ_id); + circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_FINISHED); + /* connection_ap_handshake_attach_circuit will launch a new intro circ. */ + ret = 0; + } + + end: + extend_info_free(ei); + return ret; +} + +/* Close all client introduction circuits related to the given descriptor. + * This is called with a descriptor that is about to get replaced in the + * client cache. + * + * Even though the introduction point might be exactly the same, we'll rebuild + * them if needed but the odds are very low that an existing matching + * introduction circuit exists at that stage. */ +void +hs_client_close_intro_circuits_from_desc(const hs_descriptor_t *desc) +{ + origin_circuit_t *ocirc = NULL; + + tor_assert(desc); + + /* We iterate over all client intro circuits because they aren't kept in the + * HS circuitmap. That is probably something we want to do one day. */ + while ((ocirc = circuit_get_next_intro_circ(ocirc, true))) { + if (ocirc->hs_ident == NULL) { + /* Not a v3 circuit, ignore it. */ + continue; + } + + /* Does it match any IP in the given descriptor? If not, ignore. */ + if (find_desc_intro_point_by_ident(ocirc->hs_ident, desc) == NULL) { + continue; + } + + /* We have a match. Close the circuit as consider it expired. */ + circuit_mark_for_close(TO_CIRCUIT(ocirc), END_CIRC_REASON_FINISHED); + } +} + +/* Release all the storage held by the client subsystem. */ +void +hs_client_free_all(void) +{ + /* Purge the hidden service request cache. */ + hs_purge_last_hid_serv_requests(); + client_service_authorization_free_all(); +} + +/* Purge all potentially remotely-detectable state held in the hidden + * service client code. Called on SIGNAL NEWNYM. */ +void +hs_client_purge_state(void) +{ + /* v2 subsystem. */ + rend_client_purge_state(); + + /* Cancel all descriptor fetches. Do this first so once done we are sure + * that our descriptor cache won't modified. */ + cancel_descriptor_fetches(); + /* Purge the introduction point state cache. */ + hs_cache_client_intro_state_purge(); + /* Purge the descriptor cache. */ + hs_cache_purge_as_client(); + /* Purge the last hidden service request cache. */ + hs_purge_last_hid_serv_requests(); + + log_info(LD_REND, "Hidden service client state has been purged."); +} + +/* Called when our directory information has changed. */ +void +hs_client_dir_info_changed(void) +{ + /* We have possibly reached the minimum directory information or new + * consensus so retry all pending SOCKS connection in + * AP_CONN_STATE_RENDDESC_WAIT state in order to fetch the descriptor. */ + retry_all_socks_conn_waiting_for_desc(); +} + +#ifdef TOR_UNIT_TESTS + +STATIC digest256map_t * +get_hs_client_auths_map(void) +{ + return client_auths; +} + +#endif /* defined(TOR_UNIT_TESTS) */ diff --cc src/feature/hs/hs_intropoint.c index b28a5c2b8,000000000..7717ed53d mode 100644,000000..100644 --- a/src/feature/hs/hs_intropoint.c +++ b/src/feature/hs/hs_intropoint.c @@@ -1,608 -1,0 +1,609 @@@ +/* Copyright (c) 2016-2019, The Tor Project, Inc. */ +/* See LICENSE for licensing information */ + +/** + * \file hs_intropoint.c + * \brief Implement next generation introductions point functionality + **/ + +#define HS_INTROPOINT_PRIVATE + +#include "core/or/or.h" +#include "app/config/config.h" +#include "core/or/circuitlist.h" +#include "core/or/circuituse.h" +#include "core/or/relay.h" +#include "feature/rend/rendmid.h" +#include "feature/stats/rephist.h" +#include "lib/crypt_ops/crypto_format.h" + +/* Trunnel */ +#include "trunnel/ed25519_cert.h" +#include "trunnel/hs/cell_common.h" +#include "trunnel/hs/cell_establish_intro.h" +#include "trunnel/hs/cell_introduce1.h" + +#include "feature/hs/hs_circuitmap.h" +#include "feature/hs/hs_descriptor.h" +#include "feature/hs/hs_intropoint.h" +#include "feature/hs/hs_common.h" + +#include "core/or/or_circuit_st.h" + +/** Extract the authentication key from an ESTABLISH_INTRO or INTRODUCE1 using + * the given cell_type from cell and place it in + * auth_key_out. */ +STATIC void +get_auth_key_from_cell(ed25519_public_key_t *auth_key_out, + unsigned int cell_type, const void *cell) +{ + size_t auth_key_len; + const uint8_t *key_array; + + tor_assert(auth_key_out); + tor_assert(cell); + + switch (cell_type) { + case RELAY_COMMAND_ESTABLISH_INTRO: + { + const trn_cell_establish_intro_t *c_cell = cell; + key_array = trn_cell_establish_intro_getconstarray_auth_key(c_cell); + auth_key_len = trn_cell_establish_intro_getlen_auth_key(c_cell); + break; + } + case RELAY_COMMAND_INTRODUCE1: + { + const trn_cell_introduce1_t *c_cell = cell; + key_array = trn_cell_introduce1_getconstarray_auth_key(cell); + auth_key_len = trn_cell_introduce1_getlen_auth_key(c_cell); + break; + } + default: + /* Getting here is really bad as it means we got a unknown cell type from + * this file where every call has an hardcoded value. */ + tor_assert_unreached(); /* LCOV_EXCL_LINE */ + } + tor_assert(key_array); + tor_assert(auth_key_len == sizeof(auth_key_out->pubkey)); + memcpy(auth_key_out->pubkey, key_array, auth_key_len); +} + +/** We received an ESTABLISH_INTRO cell. Verify its signature and MAC, + * given circuit_key_material. Return 0 on success else -1 on error. */ +STATIC int +verify_establish_intro_cell(const trn_cell_establish_intro_t *cell, + const uint8_t *circuit_key_material, + size_t circuit_key_material_len) +{ + /* We only reach this function if the first byte of the cell is 0x02 which + * means that auth_key_type is of ed25519 type, hence this check should + * always pass. See hs_intro_received_establish_intro(). */ - if (BUG(cell->auth_key_type != HS_INTRO_AUTH_KEY_TYPE_ED25519)) { ++ if (BUG(cell->auth_key_type != TRUNNEL_HS_INTRO_AUTH_KEY_TYPE_ED25519)) { + return -1; + } + + /* Make sure the auth key length is of the right size for this type. For + * EXTRA safety, we check both the size of the array and the length which + * must be the same. Safety first!*/ + if (trn_cell_establish_intro_getlen_auth_key(cell) != ED25519_PUBKEY_LEN || + trn_cell_establish_intro_get_auth_key_len(cell) != ED25519_PUBKEY_LEN) { + log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, + "ESTABLISH_INTRO auth key length is invalid"); + return -1; + } + + const uint8_t *msg = cell->start_cell; + + /* Verify the sig */ + { + ed25519_signature_t sig_struct; + const uint8_t *sig_array = + trn_cell_establish_intro_getconstarray_sig(cell); + + /* Make sure the signature length is of the right size. For EXTRA safety, + * we check both the size of the array and the length which must be the + * same. Safety first!*/ + if (trn_cell_establish_intro_getlen_sig(cell) != sizeof(sig_struct.sig) || + trn_cell_establish_intro_get_sig_len(cell) != sizeof(sig_struct.sig)) { + log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, + "ESTABLISH_INTRO sig len is invalid"); + return -1; + } + /* We are now sure that sig_len is of the right size. */ + memcpy(sig_struct.sig, sig_array, cell->sig_len); + + ed25519_public_key_t auth_key; + get_auth_key_from_cell(&auth_key, RELAY_COMMAND_ESTABLISH_INTRO, cell); + + const size_t sig_msg_len = cell->end_sig_fields - msg; + int sig_mismatch = ed25519_checksig_prefixed(&sig_struct, + msg, sig_msg_len, + ESTABLISH_INTRO_SIG_PREFIX, + &auth_key); + if (sig_mismatch) { + log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, + "ESTABLISH_INTRO signature not as expected"); + return -1; + } + } + + /* Verify the MAC */ + { + const size_t auth_msg_len = cell->end_mac_fields - msg; + uint8_t mac[DIGEST256_LEN]; + crypto_mac_sha3_256(mac, sizeof(mac), + circuit_key_material, circuit_key_material_len, + msg, auth_msg_len); + if (tor_memneq(mac, cell->handshake_mac, sizeof(mac))) { + log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, + "ESTABLISH_INTRO handshake_auth not as expected"); + return -1; + } + } + + return 0; +} + +/* Send an INTRO_ESTABLISHED cell to circ. */ +MOCK_IMPL(int, +hs_intro_send_intro_established_cell,(or_circuit_t *circ)) +{ + int ret; + uint8_t *encoded_cell = NULL; + ssize_t encoded_len, result_len; + trn_cell_intro_established_t *cell; + trn_cell_extension_t *ext; + + tor_assert(circ); + + /* Build the cell payload. */ + cell = trn_cell_intro_established_new(); + ext = trn_cell_extension_new(); + trn_cell_extension_set_num(ext, 0); + trn_cell_intro_established_set_extensions(cell, ext); + /* Encode the cell to binary format. */ + encoded_len = trn_cell_intro_established_encoded_len(cell); + tor_assert(encoded_len > 0); + encoded_cell = tor_malloc_zero(encoded_len); + result_len = trn_cell_intro_established_encode(encoded_cell, encoded_len, + cell); + tor_assert(encoded_len == result_len); + + ret = relay_send_command_from_edge(0, TO_CIRCUIT(circ), + RELAY_COMMAND_INTRO_ESTABLISHED, + (char *) encoded_cell, encoded_len, + NULL); + /* On failure, the above function will close the circuit. */ + trn_cell_intro_established_free(cell); + tor_free(encoded_cell); + return ret; +} + +/** We received an ESTABLISH_INTRO parsed_cell on circ. It's + * well-formed and passed our verifications. Perform appropriate actions to + * establish an intro point. */ +static int +handle_verified_establish_intro_cell(or_circuit_t *circ, + const trn_cell_establish_intro_t *parsed_cell) +{ + /* Get the auth key of this intro point */ + ed25519_public_key_t auth_key; + get_auth_key_from_cell(&auth_key, RELAY_COMMAND_ESTABLISH_INTRO, + parsed_cell); + + /* Then notify the hidden service that the intro point is established by + sending an INTRO_ESTABLISHED cell */ + if (hs_intro_send_intro_established_cell(circ)) { + log_warn(LD_PROTOCOL, "Couldn't send INTRO_ESTABLISHED cell."); + return -1; + } + + /* Associate intro point auth key with this circuit. */ + hs_circuitmap_register_intro_circ_v3_relay_side(circ, &auth_key); + /* Repurpose this circuit into an intro circuit. */ + circuit_change_purpose(TO_CIRCUIT(circ), CIRCUIT_PURPOSE_INTRO_POINT); + + return 0; +} + +/** We just received an ESTABLISH_INTRO cell in circ with payload in + * request. Handle it by making circ an intro circuit. Return 0 + * if everything went well, or -1 if there were errors. */ +static int +handle_establish_intro(or_circuit_t *circ, const uint8_t *request, + size_t request_len) +{ + int cell_ok, retval = -1; + trn_cell_establish_intro_t *parsed_cell = NULL; + + tor_assert(circ); + tor_assert(request); + + log_info(LD_REND, "Received an ESTABLISH_INTRO request on circuit %" PRIu32, + circ->p_circ_id); + + /* Check that the circuit is in shape to become an intro point */ + if (!hs_intro_circuit_is_suitable_for_establish_intro(circ)) { + goto err; + } + + /* Parse the cell */ + ssize_t parsing_result = trn_cell_establish_intro_parse(&parsed_cell, + request, request_len); + if (parsing_result < 0) { + log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, + "Rejecting %s ESTABLISH_INTRO cell.", + parsing_result == -1 ? "invalid" : "truncated"); + goto err; + } + + cell_ok = verify_establish_intro_cell(parsed_cell, + (uint8_t *) circ->rend_circ_nonce, + sizeof(circ->rend_circ_nonce)); + if (cell_ok < 0) { + log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, + "Failed to verify ESTABLISH_INTRO cell."); + goto err; + } + + /* This cell is legit. Take the appropriate actions. */ + cell_ok = handle_verified_establish_intro_cell(circ, parsed_cell); + if (cell_ok < 0) { + goto err; + } + + /* We are done! */ + retval = 0; + goto done; + + err: + /* When sending the intro establish ack, on error the circuit can be marked + * as closed so avoid a double close. */ + if (!TO_CIRCUIT(circ)->marked_for_close) { + circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_TORPROTOCOL); + } + + done: + trn_cell_establish_intro_free(parsed_cell); + return retval; +} + +/* Return True if circuit is suitable for being an intro circuit. */ +static int +circuit_is_suitable_intro_point(const or_circuit_t *circ, + const char *log_cell_type_str) +{ + tor_assert(circ); + tor_assert(log_cell_type_str); + + /* Basic circuit state sanity checks. */ + if (circ->base_.purpose != CIRCUIT_PURPOSE_OR) { + log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, + "Rejecting %s on non-OR circuit.", log_cell_type_str); + return 0; + } + + if (circ->base_.n_chan) { + log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, + "Rejecting %s on non-edge circuit.", log_cell_type_str); + return 0; + } + + /* Suitable. */ + return 1; +} + +/* Return True if circuit is suitable for being service-side intro circuit. */ +int +hs_intro_circuit_is_suitable_for_establish_intro(const or_circuit_t *circ) +{ + return circuit_is_suitable_intro_point(circ, "ESTABLISH_INTRO"); +} + +/* We just received an ESTABLISH_INTRO cell in circ. Figure out of it's + * a legacy or a next gen cell, and pass it to the appropriate handler. */ +int +hs_intro_received_establish_intro(or_circuit_t *circ, const uint8_t *request, + size_t request_len) +{ + tor_assert(circ); + tor_assert(request); + + if (request_len == 0) { + log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, "Empty ESTABLISH_INTRO cell."); + goto err; + } + + /* Using the first byte of the cell, figure out the version of + * ESTABLISH_INTRO and pass it to the appropriate cell handler */ + const uint8_t first_byte = request[0]; + switch (first_byte) { - case HS_INTRO_AUTH_KEY_TYPE_LEGACY0: - case HS_INTRO_AUTH_KEY_TYPE_LEGACY1: ++ case TRUNNEL_HS_INTRO_AUTH_KEY_TYPE_LEGACY0: ++ case TRUNNEL_HS_INTRO_AUTH_KEY_TYPE_LEGACY1: + return rend_mid_establish_intro_legacy(circ, request, request_len); - case HS_INTRO_AUTH_KEY_TYPE_ED25519: ++ case TRUNNEL_HS_INTRO_AUTH_KEY_TYPE_ED25519: + return handle_establish_intro(circ, request, request_len); + default: + log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, + "Unrecognized AUTH_KEY_TYPE %u.", first_byte); + goto err; + } + + err: + circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_TORPROTOCOL); + return -1; +} + +/* Send an INTRODUCE_ACK cell onto the circuit circ with the status + * value in status. Depending on the status, it can be ACK or a NACK. + * Return 0 on success else a negative value on error which will close the + * circuit. */ +static int - send_introduce_ack_cell(or_circuit_t *circ, hs_intro_ack_status_t status) ++send_introduce_ack_cell(or_circuit_t *circ, uint16_t status) +{ + int ret = -1; + uint8_t *encoded_cell = NULL; + ssize_t encoded_len, result_len; + trn_cell_introduce_ack_t *cell; + trn_cell_extension_t *ext; + + tor_assert(circ); + + /* Setup the INTRODUCE_ACK cell. We have no extensions so the N_EXTENSIONS + * field is set to 0 by default with a new object. */ + cell = trn_cell_introduce_ack_new(); + ret = trn_cell_introduce_ack_set_status(cell, status); + /* We have no cell extensions in an INTRODUCE_ACK cell. */ + ext = trn_cell_extension_new(); + trn_cell_extension_set_num(ext, 0); + trn_cell_introduce_ack_set_extensions(cell, ext); + /* A wrong status is a very bad code flow error as this value is controlled + * by the code in this file and not an external input. This means we use a + * code that is not known by the trunnel ABI. */ + tor_assert(ret == 0); + /* Encode the payload. We should never fail to get the encoded length. */ + encoded_len = trn_cell_introduce_ack_encoded_len(cell); + tor_assert(encoded_len > 0); + encoded_cell = tor_malloc_zero(encoded_len); + result_len = trn_cell_introduce_ack_encode(encoded_cell, encoded_len, cell); + tor_assert(encoded_len == result_len); + + ret = relay_send_command_from_edge(CONTROL_CELL_ID, TO_CIRCUIT(circ), + RELAY_COMMAND_INTRODUCE_ACK, + (char *) encoded_cell, encoded_len, + NULL); + /* On failure, the above function will close the circuit. */ + trn_cell_introduce_ack_free(cell); + tor_free(encoded_cell); + return ret; +} + +/* Validate a parsed INTRODUCE1 cell. Return 0 if valid or else a + * negative value for an invalid cell that should be NACKed. */ +STATIC int +validate_introduce1_parsed_cell(const trn_cell_introduce1_t *cell) +{ + size_t legacy_key_id_len; + const uint8_t *legacy_key_id; + + tor_assert(cell); + + /* This code path SHOULD NEVER be reached if the cell is a legacy type so + * safety net here. The legacy ID must be zeroes in this case. */ + legacy_key_id_len = trn_cell_introduce1_getlen_legacy_key_id(cell); + legacy_key_id = trn_cell_introduce1_getconstarray_legacy_key_id(cell); + if (BUG(!tor_mem_is_zero((char *) legacy_key_id, legacy_key_id_len))) { + goto invalid; + } + + /* The auth key of an INTRODUCE1 should be of type ed25519 thus leading to a + * known fixed length as well. */ + if (trn_cell_introduce1_get_auth_key_type(cell) != - HS_INTRO_AUTH_KEY_TYPE_ED25519) { ++ TRUNNEL_HS_INTRO_AUTH_KEY_TYPE_ED25519) { + log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, + "Rejecting invalid INTRODUCE1 cell auth key type. " + "Responding with NACK."); + goto invalid; + } + if (trn_cell_introduce1_get_auth_key_len(cell) != ED25519_PUBKEY_LEN || + trn_cell_introduce1_getlen_auth_key(cell) != ED25519_PUBKEY_LEN) { + log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, + "Rejecting invalid INTRODUCE1 cell auth key length. " + "Responding with NACK."); + goto invalid; + } + if (trn_cell_introduce1_getlen_encrypted(cell) == 0) { + log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, + "Rejecting invalid INTRODUCE1 cell encrypted length. " + "Responding with NACK."); + goto invalid; + } + + return 0; + invalid: + return -1; +} + +/* We just received a non legacy INTRODUCE1 cell on client_circ with + * the payload in request of size request_len. Return 0 if + * everything went well, or -1 if an error occurred. This function is in charge + * of sending back an INTRODUCE_ACK cell and will close client_circ on error. + */ +STATIC int +handle_introduce1(or_circuit_t *client_circ, const uint8_t *request, + size_t request_len) +{ + int ret = -1; + or_circuit_t *service_circ; + trn_cell_introduce1_t *parsed_cell; - hs_intro_ack_status_t status = HS_INTRO_ACK_STATUS_SUCCESS; ++ uint16_t status = TRUNNEL_HS_INTRO_ACK_STATUS_SUCCESS; + + tor_assert(client_circ); + tor_assert(request); + + /* Parse cell. Note that we can only parse the non encrypted section for + * which we'll use the authentication key to find the service introduction + * circuit and relay the cell on it. */ + ssize_t cell_size = trn_cell_introduce1_parse(&parsed_cell, request, + request_len); + if (cell_size < 0) { + log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, + "Rejecting %s INTRODUCE1 cell. Responding with NACK.", + cell_size == -1 ? "invalid" : "truncated"); + /* Inform client that the INTRODUCE1 has a bad format. */ - status = HS_INTRO_ACK_STATUS_BAD_FORMAT; ++ status = TRUNNEL_HS_INTRO_ACK_STATUS_BAD_FORMAT; + goto send_ack; + } + + /* Once parsed validate the cell format. */ + if (validate_introduce1_parsed_cell(parsed_cell) < 0) { + /* Inform client that the INTRODUCE1 has bad format. */ - status = HS_INTRO_ACK_STATUS_BAD_FORMAT; ++ status = TRUNNEL_HS_INTRO_ACK_STATUS_BAD_FORMAT; + goto send_ack; + } + + /* Find introduction circuit through our circuit map. */ + { + ed25519_public_key_t auth_key; + get_auth_key_from_cell(&auth_key, RELAY_COMMAND_INTRODUCE1, parsed_cell); + service_circ = hs_circuitmap_get_intro_circ_v3_relay_side(&auth_key); + if (service_circ == NULL) { + char b64_key[ED25519_BASE64_LEN + 1]; + ed25519_public_to_base64(b64_key, &auth_key); + log_info(LD_REND, "No intro circuit found for INTRODUCE1 cell " + "with auth key %s from circuit %" PRIu32 ". " + "Responding with NACK.", + safe_str(b64_key), client_circ->p_circ_id); + /* Inform the client that we don't know the requested service ID. */ - status = HS_INTRO_ACK_STATUS_UNKNOWN_ID; ++ status = TRUNNEL_HS_INTRO_ACK_STATUS_UNKNOWN_ID; + goto send_ack; + } + } + + /* Relay the cell to the service on its intro circuit with an INTRODUCE2 + * cell which is the same exact payload. */ + if (relay_send_command_from_edge(CONTROL_CELL_ID, TO_CIRCUIT(service_circ), + RELAY_COMMAND_INTRODUCE2, + (char *) request, request_len, NULL)) { + log_warn(LD_PROTOCOL, "Unable to send INTRODUCE2 cell to the service."); - /* Inform the client that we can't relay the cell. */ - status = HS_INTRO_ACK_STATUS_CANT_RELAY; ++ /* Inform the client that we can't relay the cell. Use the unknown ID ++ * status code since it means that we do not know the service. */ ++ status = TRUNNEL_HS_INTRO_ACK_STATUS_UNKNOWN_ID; + goto send_ack; + } + + /* Success! Send an INTRODUCE_ACK success status onto the client circuit. */ - status = HS_INTRO_ACK_STATUS_SUCCESS; ++ status = TRUNNEL_HS_INTRO_ACK_STATUS_SUCCESS; + ret = 0; + + send_ack: + /* Send INTRODUCE_ACK or INTRODUCE_NACK to client */ + if (send_introduce_ack_cell(client_circ, status) < 0) { + log_warn(LD_PROTOCOL, "Unable to send an INTRODUCE ACK status %d " + "to client.", status); + /* Circuit has been closed on failure of transmission. */ + goto done; + } + done: + trn_cell_introduce1_free(parsed_cell); + return ret; +} + +/* Identify if the encoded cell we just received is a legacy one or not. The + * request should be at least DIGEST_LEN bytes long. */ +STATIC int +introduce1_cell_is_legacy(const uint8_t *request) +{ + tor_assert(request); + + /* If the first 20 bytes of the cell (DIGEST_LEN) are NOT zeroes, it + * indicates a legacy cell (v2). */ + if (!tor_mem_is_zero((const char *) request, DIGEST_LEN)) { + /* Legacy cell. */ + return 1; + } + /* Not a legacy cell. */ + return 0; +} + +/* Return true iff the circuit circ is suitable for receiving an + * INTRODUCE1 cell. */ +STATIC int +circuit_is_suitable_for_introduce1(const or_circuit_t *circ) +{ + tor_assert(circ); + + /* Is this circuit an intro point circuit? */ + if (!circuit_is_suitable_intro_point(circ, "INTRODUCE1")) { + return 0; + } + + if (circ->already_received_introduce1) { + log_fn(LOG_PROTOCOL_WARN, LD_REND, + "Blocking multiple introductions on the same circuit. " + "Someone might be trying to attack a hidden service through " + "this relay."); + return 0; + } + + return 1; +} + +/* We just received an INTRODUCE1 cell on circ. Figure out which type + * it is and pass it to the appropriate handler. Return 0 on success else a + * negative value and the circuit is closed. */ +int +hs_intro_received_introduce1(or_circuit_t *circ, const uint8_t *request, + size_t request_len) +{ + int ret; + + tor_assert(circ); + tor_assert(request); + + /* A cell that can't hold a DIGEST_LEN is invalid as we need to check if + * it's a legacy cell or not using the first DIGEST_LEN bytes. */ + if (request_len < DIGEST_LEN) { + log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, "Invalid INTRODUCE1 cell length."); + goto err; + } + + /* Make sure we have a circuit that can have an INTRODUCE1 cell on it. */ + if (!circuit_is_suitable_for_introduce1(circ)) { + /* We do not send a NACK because the circuit is not suitable for any kind + * of response or transmission as it's a violation of the protocol. */ + goto err; + } + /* Mark the circuit that we got this cell. None are allowed after this as a + * DoS mitigation since one circuit with one client can hammer a service. */ + circ->already_received_introduce1 = 1; + + /* We are sure here to have at least DIGEST_LEN bytes. */ + if (introduce1_cell_is_legacy(request)) { + /* Handle a legacy cell. */ + ret = rend_mid_introduce_legacy(circ, request, request_len); + } else { + /* Handle a non legacy cell. */ + ret = handle_introduce1(circ, request, request_len); + } + return ret; + + err: + circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_TORPROTOCOL); + return -1; +} + +/* Clear memory allocated by the given intropoint object ip (but don't free the + * object itself). */ +void +hs_intropoint_clear(hs_intropoint_t *ip) +{ + if (ip == NULL) { + return; + } + tor_cert_free(ip->auth_key_cert); + SMARTLIST_FOREACH(ip->link_specifiers, hs_desc_link_specifier_t *, ls, + hs_desc_link_specifier_free(ls)); + smartlist_free(ip->link_specifiers); + memset(ip, 0, sizeof(hs_intropoint_t)); +} diff --cc src/feature/hs/hs_intropoint.h index 659a9ad05,000000000..e82575f05 mode 100644,000000..100644 --- a/src/feature/hs/hs_intropoint.h +++ b/src/feature/hs/hs_intropoint.h @@@ -1,79 -1,0 +1,64 @@@ +/* Copyright (c) 2016-2019, The Tor Project, Inc. */ +/* See LICENSE for licensing information */ + +/** + * \file hs_intropoint.h + * \brief Header file for hs_intropoint.c. + **/ + +#ifndef TOR_HS_INTRO_H +#define TOR_HS_INTRO_H + +#include "lib/crypt_ops/crypto_curve25519.h" +#include "feature/nodelist/torcert.h" + - /* Authentication key type in an ESTABLISH_INTRO cell. */ - typedef enum { - HS_INTRO_AUTH_KEY_TYPE_LEGACY0 = 0x00, - HS_INTRO_AUTH_KEY_TYPE_LEGACY1 = 0x01, - HS_INTRO_AUTH_KEY_TYPE_ED25519 = 0x02, - } hs_intro_auth_key_type_t; - - /* INTRODUCE_ACK status code. */ - typedef enum { - HS_INTRO_ACK_STATUS_SUCCESS = 0x0000, - HS_INTRO_ACK_STATUS_UNKNOWN_ID = 0x0001, - HS_INTRO_ACK_STATUS_BAD_FORMAT = 0x0002, - HS_INTRO_ACK_STATUS_CANT_RELAY = 0x0003, - } hs_intro_ack_status_t; - +/* Object containing introduction point common data between the service and + * the client side. */ +typedef struct hs_intropoint_t { + /* Does this intro point only supports legacy ID ?. */ + unsigned int is_only_legacy : 1; + + /* Authentication key certificate from the descriptor. */ + tor_cert_t *auth_key_cert; + /* A list of link specifier. */ + smartlist_t *link_specifiers; +} hs_intropoint_t; + +int hs_intro_received_establish_intro(or_circuit_t *circ, + const uint8_t *request, + size_t request_len); +int hs_intro_received_introduce1(or_circuit_t *circ, const uint8_t *request, + size_t request_len); + +MOCK_DECL(int, hs_intro_send_intro_established_cell,(or_circuit_t *circ)); + +/* also used by rendservice.c */ +int hs_intro_circuit_is_suitable_for_establish_intro(const or_circuit_t *circ); + +hs_intropoint_t *hs_intro_new(void); +void hs_intropoint_clear(hs_intropoint_t *ip); + +#ifdef HS_INTROPOINT_PRIVATE + +#include "trunnel/hs/cell_establish_intro.h" +#include "trunnel/hs/cell_introduce1.h" + +STATIC int +verify_establish_intro_cell(const trn_cell_establish_intro_t *out, + const uint8_t *circuit_key_material, + size_t circuit_key_material_len); + +STATIC void +get_auth_key_from_cell(ed25519_public_key_t *auth_key_out, + unsigned int cell_type, const void *cell); + +STATIC int introduce1_cell_is_legacy(const uint8_t *request); +STATIC int handle_introduce1(or_circuit_t *client_circ, + const uint8_t *request, size_t request_len); +STATIC int validate_introduce1_parsed_cell(const trn_cell_introduce1_t *cell); +STATIC int circuit_is_suitable_for_introduce1(const or_circuit_t *circ); + +#endif /* defined(HS_INTROPOINT_PRIVATE) */ + +#endif /* !defined(TOR_HS_INTRO_H) */ +

1 0

[tor/maint-0.3.5] changes file for bug 29875.
by teor＠torproject.org 12 Aug '19

12 Aug '19

commit c09e7a4e715d8266517896cfbc8fc80f19feba85 Author: Nick Mathewson <nickm(a)torproject.org> Date: Fri May 31 12:39:52 2019 -0400 changes file for bug 29875. --- changes/bug29875 | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/changes/bug29875 b/changes/bug29875 new file mode 100644 index 000000000..58a1c871c --- /dev/null +++ b/changes/bug29875 @@ -0,0 +1,11 @@ + o Major bugfixes (bridges): + - Do not count previously configured working bridges towards our total of + working bridges. Previously, when Tor's list of bridges changed, it + would think that the old bridges were still usable, and delay fetching + router descriptors for the new ones. Fixes part of bug 29875; bugfix + on 0.3.0.1-alpha. + - Consider our directory information to have changed when our list of + bridges changes. Previously, Tor would not re-compute the status of its + directory information when bridges changed, and therefore would not + realize that it was no longer able to build circuits. Fixes part of bug + 29875.

1 0

[tor/maint-0.3.5] Fix a logic error in deciding whether to accept SessionGroup=
by teor＠torproject.org 12 Aug '19

12 Aug '19

commit 70b85358afd0a8d4291489f9e9f5654ab2d53371 Author: Nick Mathewson <nickm(a)torproject.org> Date: Fri May 31 08:26:10 2019 -0400 Fix a logic error in deciding whether to accept SessionGroup= Fixes bug 22619; bugfix on 0.2.7.2-alpha --- changes/bug22619 | 3 +++ src/app/config/config.c | 2 +- 2 files changed, 4 insertions(+), 1 deletion(-) diff --git a/changes/bug22619 b/changes/bug22619 new file mode 100644 index 000000000..9c71996f5 --- /dev/null +++ b/changes/bug22619 @@ -0,0 +1,3 @@ + o Minor bugfixes (circuit isolation): + - Fix a logic error that prevented the SessionGroup sub-option from + being accepted. Fixes bug 22619; bugfix on 0.2.7.2-alpha. diff --git a/src/app/config/config.c b/src/app/config/config.c index 2a504d306..352559759 100644 --- a/src/app/config/config.c +++ b/src/app/config/config.c @@ -7080,7 +7080,7 @@ parse_port_config(smartlist_t *out, if (!strcasecmpstart(elt, "SessionGroup=")) { int group = (int)tor_parse_long(elt+strlen("SessionGroup="), 10, 0, INT_MAX, &ok, NULL); - if (!ok || !allow_no_stream_options) { + if (!ok || allow_no_stream_options) { log_warn(LD_CONFIG, "Invalid %sPort option '%s'", portname, escaped(elt)); goto err;

1 0

[tor/maint-0.3.5] Merge remote-tracking branch 'tor-github/pr/937' into maint-0.3.5
by teor＠torproject.org 12 Aug '19

12 Aug '19

commit ef345ab56d26e51f5d1f1a0b51e55a589465669b Merge: 9be65c440 85ff6f911 Author: teor <teor(a)torproject.org> Date: Mon Aug 12 09:42:15 2019 +1000 Merge remote-tracking branch 'tor-github/pr/937' into maint-0.3.5 changes/bug30148 | 4 ++++ src/feature/relay/routerkeys.c | 2 +- 2 files changed, 5 insertions(+), 1 deletion(-) diff --cc src/feature/relay/routerkeys.c index 876f908d4,000000000..f639fc91e mode 100644,000000..100644 --- a/src/feature/relay/routerkeys.c +++ b/src/feature/relay/routerkeys.c @@@ -1,740 -1,0 +1,740 @@@ +/* Copyright (c) 2014-2019, The Tor Project, Inc. */ +/* See LICENSE for licensing information */ + +/** + * \file routerkeys.c + * + * \brief Functions and structures to handle generating and maintaining the + * set of keypairs necessary to be an OR. + * + * The keys handled here now are the Ed25519 keys that Tor relays use to sign + * descriptors, authenticate themselves on links, and identify one another + * uniquely. Other keys are maintained in router.c and rendservice.c. + * + * (TODO: The keys in router.c should go here too.) + */ + +#include "core/or/or.h" +#include "app/config/config.h" +#include "feature/relay/router.h" +#include "feature/relay/routerkeys.h" +#include "feature/relay/routermode.h" +#include "feature/keymgt/loadkey.h" +#include "feature/nodelist/torcert.h" + +#include "lib/crypt_ops/crypto_util.h" +#include "lib/tls/tortls.h" +#include "lib/tls/x509.h" + +#define ENC_KEY_HEADER "Boxed Ed25519 key" +#define ENC_KEY_TAG "master" + +#ifdef HAVE_UNISTD_H +#include <unistd.h> +#endif + +static ed25519_keypair_t *master_identity_key = NULL; +static ed25519_keypair_t *master_signing_key = NULL; +static ed25519_keypair_t *current_auth_key = NULL; +static tor_cert_t *signing_key_cert = NULL; +static tor_cert_t *link_cert_cert = NULL; +static tor_cert_t *auth_key_cert = NULL; + +static uint8_t *rsa_ed_crosscert = NULL; +static size_t rsa_ed_crosscert_len = 0; +static time_t rsa_ed_crosscert_expiration = 0; + +/** + * Running as a server: load, reload, or refresh our ed25519 keys and + * certificates, creating and saving new ones as needed. + * + * Return -1 on failure; 0 on success if the signing key was not replaced; + * and 1 on success if the signing key was replaced. + */ +int +load_ed_keys(const or_options_t *options, time_t now) +{ + ed25519_keypair_t *id = NULL; + ed25519_keypair_t *sign = NULL; + ed25519_keypair_t *auth = NULL; + const ed25519_keypair_t *sign_signing_key_with_id = NULL; + const ed25519_keypair_t *use_signing = NULL; + const tor_cert_t *check_signing_cert = NULL; + tor_cert_t *sign_cert = NULL; + tor_cert_t *auth_cert = NULL; + int signing_key_changed = 0; + + // It is later than 1972, since otherwise there would be no C compilers. + // (Try to diagnose #22466.) + tor_assert_nonfatal(now >= 2 * 365 * 86400); + +#define FAIL(msg) do { \ + log_warn(LD_OR, (msg)); \ + goto err; \ + } while (0) +#define SET_KEY(key, newval) do { \ + if ((key) != (newval)) \ + ed25519_keypair_free(key); \ + key = (newval); \ + } while (0) +#define SET_CERT(cert, newval) do { \ + if ((cert) != (newval)) \ + tor_cert_free(cert); \ + cert = (newval); \ + } while (0) +#define HAPPENS_SOON(when, interval) \ + ((when) < now + (interval)) +#define EXPIRES_SOON(cert, interval) \ + (!(cert) || HAPPENS_SOON((cert)->valid_until, (interval))) + + /* XXXX support encrypted identity keys fully */ + + /* First try to get the signing key to see how it is. */ + { + char *fname = + options_get_keydir_fname(options, "ed25519_signing"); + sign = ed_key_init_from_file( + fname, + INIT_ED_KEY_NEEDCERT| + INIT_ED_KEY_INCLUDE_SIGNING_KEY_IN_CERT, + LOG_INFO, + NULL, 0, 0, CERT_TYPE_ID_SIGNING, &sign_cert, options); + tor_free(fname); + check_signing_cert = sign_cert; + use_signing = sign; + } + + if (use_signing) { + /* We loaded a signing key with its certificate. */ + if (! master_signing_key) { + /* We didn't know one before! */ + signing_key_changed = 1; + } else if (! ed25519_pubkey_eq(&use_signing->pubkey, + &master_signing_key->pubkey) || + ! tor_memeq(use_signing->seckey.seckey, + master_signing_key->seckey.seckey, + ED25519_SECKEY_LEN)) { + /* We loaded a different signing key than the one we knew before. */ + signing_key_changed = 1; + } + } + + if (!use_signing && master_signing_key) { + /* We couldn't load a signing key, but we already had one loaded */ + check_signing_cert = signing_key_cert; + use_signing = master_signing_key; + } + + const int offline_master = + options->OfflineMasterKey && options->command != CMD_KEYGEN; + const int need_new_signing_key = + NULL == use_signing || + EXPIRES_SOON(check_signing_cert, 0) || + (options->command == CMD_KEYGEN && ! options->change_key_passphrase); + const int want_new_signing_key = + need_new_signing_key || + EXPIRES_SOON(check_signing_cert, options->TestingSigningKeySlop); + + /* We can only create a master key if we haven't been told that the + * master key will always be offline. Also, if we have a signing key, + * then we shouldn't make a new master ID key. */ + const int can_make_master_id_key = !offline_master && + NULL == use_signing; + + if (need_new_signing_key) { + log_notice(LD_OR, "It looks like I need to generate and sign a new " + "medium-term signing key, because %s. To do that, I " + "need to load%s the permanent master identity key. " + "If the master identity key was not moved or encrypted " + "with a passphrase, this will be done automatically and " + "no further action is required. Otherwise, provide the " + "necessary data using 'tor --keygen' to do it manually.", + (NULL == use_signing) ? "I don't have one" : + EXPIRES_SOON(check_signing_cert, 0) ? "the one I have is expired" : + "you asked me to make one with --keygen", + can_make_master_id_key ? " (or create)" : ""); + } else if (want_new_signing_key && !offline_master) { + log_notice(LD_OR, "It looks like I should try to generate and sign a " + "new medium-term signing key, because the one I have is " + "going to expire soon. To do that, I'm going to have to " + "try to load the permanent master identity key. " + "If the master identity key was not moved or encrypted " + "with a passphrase, this will be done automatically and " + "no further action is required. Otherwise, provide the " + "necessary data using 'tor --keygen' to do it manually."); + } else if (want_new_signing_key) { + log_notice(LD_OR, "It looks like I should try to generate and sign a " + "new medium-term signing key, because the one I have is " + "going to expire soon. But OfflineMasterKey is set, so I " + "won't try to load a permanent master identity key. You " + "will need to use 'tor --keygen' to make a new signing " + "key and certificate."); + } + + { + uint32_t flags = + (INIT_ED_KEY_SPLIT| + INIT_ED_KEY_EXTRA_STRONG|INIT_ED_KEY_NO_REPAIR); + if (can_make_master_id_key) + flags |= INIT_ED_KEY_CREATE; + if (! need_new_signing_key) + flags |= INIT_ED_KEY_MISSING_SECRET_OK; + if (! want_new_signing_key || offline_master) + flags |= INIT_ED_KEY_OMIT_SECRET; + if (offline_master) + flags |= INIT_ED_KEY_OFFLINE_SECRET; + if (options->command == CMD_KEYGEN) + flags |= INIT_ED_KEY_TRY_ENCRYPTED; + + /* Check/Create the key directory */ + if (create_keys_directory(options) < 0) - return -1; ++ goto err; + + char *fname; + if (options->master_key_fname) { + fname = tor_strdup(options->master_key_fname); + flags |= INIT_ED_KEY_EXPLICIT_FNAME; + } else { + fname = options_get_keydir_fname(options, "ed25519_master_id"); + } + id = ed_key_init_from_file( + fname, + flags, + LOG_WARN, NULL, 0, 0, 0, NULL, options); + tor_free(fname); + if (!id) { + if (need_new_signing_key) { + if (offline_master) + FAIL("Can't load master identity key; OfflineMasterKey is set."); + else + FAIL("Missing identity key"); + } else { + log_warn(LD_OR, "Master public key was absent; inferring from " + "public key in signing certificate and saving to disk."); + tor_assert(check_signing_cert); + id = tor_malloc_zero(sizeof(*id)); + memcpy(&id->pubkey, &check_signing_cert->signing_key, + sizeof(ed25519_public_key_t)); + fname = options_get_keydir_fname(options, + "ed25519_master_id_public_key"); + if (ed25519_pubkey_write_to_file(&id->pubkey, fname, "type0") < 0) { + log_warn(LD_OR, "Error while attempting to write master public key " + "to disk"); + tor_free(fname); + goto err; + } + tor_free(fname); + } + } + if (tor_mem_is_zero((char*)id->seckey.seckey, sizeof(id->seckey))) + sign_signing_key_with_id = NULL; + else + sign_signing_key_with_id = id; + } + + if (master_identity_key && + !ed25519_pubkey_eq(&id->pubkey, &master_identity_key->pubkey)) { + FAIL("Identity key on disk does not match key we loaded earlier!"); + } + + if (need_new_signing_key && NULL == sign_signing_key_with_id) + FAIL("Can't load master key make a new signing key."); + + if (sign_cert) { + if (! sign_cert->signing_key_included) + FAIL("Loaded a signing cert with no key included!"); + if (! ed25519_pubkey_eq(&sign_cert->signing_key, &id->pubkey)) + FAIL("The signing cert we have was not signed with the master key " + "we loaded!"); + if (tor_cert_checksig(sign_cert, &id->pubkey, 0) < 0) { + log_warn(LD_OR, "The signing cert we loaded was not signed " + "correctly: %s!", + tor_cert_describe_signature_status(sign_cert)); + goto err; + } + } + + if (want_new_signing_key && sign_signing_key_with_id) { + uint32_t flags = (INIT_ED_KEY_CREATE| + INIT_ED_KEY_REPLACE| + INIT_ED_KEY_EXTRA_STRONG| + INIT_ED_KEY_NEEDCERT| + INIT_ED_KEY_INCLUDE_SIGNING_KEY_IN_CERT); + char *fname = + options_get_keydir_fname(options, "ed25519_signing"); + ed25519_keypair_free(sign); + tor_cert_free(sign_cert); + sign = ed_key_init_from_file(fname, + flags, LOG_WARN, + sign_signing_key_with_id, now, + options->SigningKeyLifetime, + CERT_TYPE_ID_SIGNING, &sign_cert, options); + tor_free(fname); + if (!sign) + FAIL("Missing signing key"); + use_signing = sign; + signing_key_changed = 1; + + tor_assert(sign_cert->signing_key_included); + tor_assert(ed25519_pubkey_eq(&sign_cert->signing_key, &id->pubkey)); + tor_assert(ed25519_pubkey_eq(&sign_cert->signed_key, &sign->pubkey)); + } else if (want_new_signing_key) { + static ratelim_t missing_master = RATELIM_INIT(3600); + log_fn_ratelim(&missing_master, LOG_WARN, LD_OR, + "Signing key will expire soon, but I can't load the " + "master key to sign a new one!"); + } + + tor_assert(use_signing); + + /* At this point we no longer need our secret identity key. So wipe + * it, if we loaded it in the first place. */ + memwipe(id->seckey.seckey, 0, sizeof(id->seckey)); + + if (options->command == CMD_KEYGEN) + goto end; + + if (server_mode(options) && + (!rsa_ed_crosscert || + HAPPENS_SOON(rsa_ed_crosscert_expiration, 30*86400))) { + uint8_t *crosscert; + time_t expiration = now+6*30*86400; /* 6 months in the future. */ + ssize_t crosscert_len = tor_make_rsa_ed25519_crosscert(&id->pubkey, + get_server_identity_key(), + expiration, + &crosscert); + tor_free(rsa_ed_crosscert); + rsa_ed_crosscert_len = crosscert_len; + rsa_ed_crosscert = crosscert; + rsa_ed_crosscert_expiration = expiration; + } + + if (!current_auth_key || + signing_key_changed || + EXPIRES_SOON(auth_key_cert, options->TestingAuthKeySlop)) { + auth = ed_key_new(use_signing, INIT_ED_KEY_NEEDCERT, + now, + options->TestingAuthKeyLifetime, + CERT_TYPE_SIGNING_AUTH, &auth_cert); + + if (!auth) + FAIL("Can't create auth key"); + } + + /* We've generated or loaded everything. Put them in memory. */ + + end: + if (! master_identity_key) { + SET_KEY(master_identity_key, id); + } else { + tor_free(id); + } + if (sign) { + SET_KEY(master_signing_key, sign); + SET_CERT(signing_key_cert, sign_cert); + } + if (auth) { + SET_KEY(current_auth_key, auth); + SET_CERT(auth_key_cert, auth_cert); + } + + return signing_key_changed; + err: + ed25519_keypair_free(id); + ed25519_keypair_free(sign); + ed25519_keypair_free(auth); + tor_cert_free(sign_cert); + tor_cert_free(auth_cert); + return -1; +} + +/** + * Retrieve our currently-in-use Ed25519 link certificate and id certificate, + * and, if they would expire soon (based on the time now, generate new + * certificates (without embedding the public part of the signing key inside). + * If force is true, always generate a new certificate. + * + * The signed_key from the current id->signing certificate will be used to + * sign the new key within newly generated X509 certificate. + * + * Returns -1 upon error. Otherwise, returns 0 upon success (either when the + * current certificate is still valid, or when a new certificate was + * successfully generated, or no certificate was needed). + */ +int +generate_ed_link_cert(const or_options_t *options, time_t now, + int force) +{ + const tor_x509_cert_t *link_ = NULL, *id = NULL; + tor_cert_t *link_cert = NULL; + + if (tor_tls_get_my_certs(1, &link_, &id) < 0 || link_ == NULL) { + if (!server_mode(options)) { + /* No need to make an Ed25519->Link cert: we are a client */ + return 0; + } + log_warn(LD_OR, "Can't get my x509 link cert."); + return -1; + } + + const common_digests_t *digests = tor_x509_cert_get_cert_digests(link_); + + if (force == 0 && + link_cert_cert && + ! EXPIRES_SOON(link_cert_cert, options->TestingLinkKeySlop) && + fast_memeq(digests->d[DIGEST_SHA256], link_cert_cert->signed_key.pubkey, + DIGEST256_LEN)) { + return 0; + } + + ed25519_public_key_t dummy_key; + memcpy(dummy_key.pubkey, digests->d[DIGEST_SHA256], DIGEST256_LEN); + + link_cert = tor_cert_create(get_master_signing_keypair(), + CERT_TYPE_SIGNING_LINK, + &dummy_key, + now, + options->TestingLinkCertLifetime, 0); + + if (link_cert) { + SET_CERT(link_cert_cert, link_cert); + } + return 0; +} + +#undef FAIL +#undef SET_KEY +#undef SET_CERT + +/** + * Return 1 if any of the following are true: + * + * - if one of our Ed25519 signing, auth, or link certificates would expire + * soon w.r.t. the time now, + * - if we do not currently have a link certificate, or + * - if our cached Ed25519 link certificate is not same as the one we're + * currently using. + * + * Otherwise, returns 0. + */ +int +should_make_new_ed_keys(const or_options_t *options, const time_t now) +{ + if (!master_identity_key || + !master_signing_key || + !current_auth_key || + !link_cert_cert || + EXPIRES_SOON(signing_key_cert, options->TestingSigningKeySlop) || + EXPIRES_SOON(auth_key_cert, options->TestingAuthKeySlop) || + EXPIRES_SOON(link_cert_cert, options->TestingLinkKeySlop)) + return 1; + + const tor_x509_cert_t *link_ = NULL, *id = NULL; + + if (tor_tls_get_my_certs(1, &link_, &id) < 0 || link_ == NULL) + return 1; + + const common_digests_t *digests = tor_x509_cert_get_cert_digests(link_); + + if (!fast_memeq(digests->d[DIGEST_SHA256], + link_cert_cert->signed_key.pubkey, + DIGEST256_LEN)) { + return 1; + } + + return 0; +} + +#undef EXPIRES_SOON +#undef HAPPENS_SOON + +#ifdef TOR_UNIT_TESTS +/* Helper for unit tests: populate the ed25519 keys without saving or + * loading */ +void +init_mock_ed_keys(const crypto_pk_t *rsa_identity_key) +{ + routerkeys_free_all(); + +#define MAKEKEY(k) \ + k = tor_malloc_zero(sizeof(*k)); \ + if (ed25519_keypair_generate(k, 0) < 0) { \ + log_warn(LD_BUG, "Couldn't make a keypair"); \ + goto err; \ + } + MAKEKEY(master_identity_key); + MAKEKEY(master_signing_key); + MAKEKEY(current_auth_key); +#define MAKECERT(cert, signing, signed_, type, flags) \ + cert = tor_cert_create(signing, \ + type, \ + &signed_->pubkey, \ + time(NULL), 86400, \ + flags); \ + if (!cert) { \ + log_warn(LD_BUG, "Couldn't make a %s certificate!", #cert); \ + goto err; \ + } + + MAKECERT(signing_key_cert, + master_identity_key, master_signing_key, CERT_TYPE_ID_SIGNING, + CERT_FLAG_INCLUDE_SIGNING_KEY); + MAKECERT(auth_key_cert, + master_signing_key, current_auth_key, CERT_TYPE_SIGNING_AUTH, 0); + + if (generate_ed_link_cert(get_options(), time(NULL), 0) < 0) { + log_warn(LD_BUG, "Couldn't make link certificate"); + goto err; + } + + rsa_ed_crosscert_len = tor_make_rsa_ed25519_crosscert( + &master_identity_key->pubkey, + rsa_identity_key, + time(NULL)+86400, + &rsa_ed_crosscert); + + return; + + err: + routerkeys_free_all(); + tor_assert_nonfatal_unreached(); +} +#undef MAKEKEY +#undef MAKECERT +#endif /* defined(TOR_UNIT_TESTS) */ + +/** + * Print the ISO8601-formated expiration for a certificate with + * some description to stdout. + * + * For example, for a signing certificate, this might print out: + * signing-cert-expiry: 2017-07-25 08:30:15 UTC + */ +static void +print_cert_expiration(const char *expiration, + const char *description) +{ + fprintf(stderr, "%s-cert-expiry: %s\n", description, expiration); +} + +/** + * Log when a certificate, cert, with some description and + * stored in a file named fname, is going to expire. + */ +static void +log_ed_cert_expiration(const tor_cert_t *cert, + const char *description, + const char *fname) { + char expiration[ISO_TIME_LEN+1]; + + if (BUG(!cert)) { /* If the specified key hasn't been loaded */ + log_warn(LD_OR, "No %s key loaded; can't get certificate expiration.", + description); + } else { + format_local_iso_time(expiration, cert->valid_until); + log_notice(LD_OR, "The %s certificate stored in %s is valid until %s.", + description, fname, expiration); + print_cert_expiration(expiration, description); + } +} + +/** + * Log when our master signing key certificate expires. Used when tor is given + * the --key-expiration command-line option. + * + * Returns 0 on success and 1 on failure. + */ +static int +log_master_signing_key_cert_expiration(const or_options_t *options) +{ + const tor_cert_t *signing_key; + char *fn = NULL; + int failed = 0; + time_t now = approx_time(); + + fn = options_get_keydir_fname(options, "ed25519_signing_cert"); + + /* Try to grab our cached copy of the key. */ + signing_key = get_master_signing_key_cert(); + + tor_assert(server_identity_key_is_set()); + + /* Load our keys from disk, if necessary. */ + if (!signing_key) { + failed = load_ed_keys(options, now) < 0; + signing_key = get_master_signing_key_cert(); + } + + /* If we do have a signing key, log the expiration time. */ + if (signing_key) { + log_ed_cert_expiration(signing_key, "signing", fn); + } else { + log_warn(LD_OR, "Could not load signing key certificate from %s, so " \ + "we couldn't learn anything about certificate expiration.", fn); + } + + tor_free(fn); + + return failed; +} + +/** + * Log when a key certificate expires. Used when tor is given the + * --key-expiration command-line option. + * + * If an command argument is given, which should specify the type of + * key to get expiry information about (currently supported arguments + * are "sign"), get info about that type of certificate. Otherwise, + * print info about the supported arguments. + * + * Returns 0 on success and -1 on failure. + */ +int +log_cert_expiration(void) +{ + const or_options_t *options = get_options(); + const char *arg = options->command_arg; + + if (!strcmp(arg, "sign")) { + return log_master_signing_key_cert_expiration(options); + } else { + fprintf(stderr, "No valid argument to --key-expiration found!\n"); + fprintf(stderr, "Currently recognised arguments are: 'sign'\n"); + + return -1; + } +} + +const ed25519_public_key_t * +get_master_identity_key(void) +{ + if (!master_identity_key) + return NULL; + return &master_identity_key->pubkey; +} + +/** Return true iff id is our Ed25519 master identity key. */ +int +router_ed25519_id_is_me(const ed25519_public_key_t *id) +{ + return id && master_identity_key && + ed25519_pubkey_eq(id, &master_identity_key->pubkey); +} + +#ifdef TOR_UNIT_TESTS +/* only exists for the unit tests, since otherwise the identity key + * should be used to sign nothing but the signing key. */ +const ed25519_keypair_t * +get_master_identity_keypair(void) +{ + return master_identity_key; +} +#endif /* defined(TOR_UNIT_TESTS) */ + +const ed25519_keypair_t * +get_master_signing_keypair(void) +{ + return master_signing_key; +} + +const struct tor_cert_st * +get_master_signing_key_cert(void) +{ + return signing_key_cert; +} + +const ed25519_keypair_t * +get_current_auth_keypair(void) +{ + return current_auth_key; +} + +const tor_cert_t * +get_current_link_cert_cert(void) +{ + return link_cert_cert; +} + +const tor_cert_t * +get_current_auth_key_cert(void) +{ + return auth_key_cert; +} + +void +get_master_rsa_crosscert(const uint8_t **cert_out, + size_t *size_out) +{ + *cert_out = rsa_ed_crosscert; + *size_out = rsa_ed_crosscert_len; +} + +/** Construct cross-certification for the master identity key with + * the ntor onion key. Store the sign of the corresponding ed25519 public key + * in *sign_out. */ +tor_cert_t * +make_ntor_onion_key_crosscert(const curve25519_keypair_t *onion_key, + const ed25519_public_key_t *master_id_key, time_t now, time_t lifetime, + int *sign_out) +{ + tor_cert_t *cert = NULL; + ed25519_keypair_t ed_onion_key; + + if (ed25519_keypair_from_curve25519_keypair(&ed_onion_key, sign_out, + onion_key) < 0) + goto end; + + cert = tor_cert_create(&ed_onion_key, CERT_TYPE_ONION_ID, master_id_key, + now, lifetime, 0); + + end: + memwipe(&ed_onion_key, 0, sizeof(ed_onion_key)); + return cert; +} + +/** Construct and return an RSA signature for the TAP onion key to + * cross-certify the RSA and Ed25519 identity keys. Set len_out to its + * length. */ +uint8_t * +make_tap_onion_key_crosscert(const crypto_pk_t *onion_key, + const ed25519_public_key_t *master_id_key, + const crypto_pk_t *rsa_id_key, + int *len_out) +{ + uint8_t signature[PK_BYTES]; + uint8_t signed_data[DIGEST_LEN + ED25519_PUBKEY_LEN]; + + *len_out = 0; + if (crypto_pk_get_digest(rsa_id_key, (char*)signed_data) < 0) { + return NULL; + } + memcpy(signed_data + DIGEST_LEN, master_id_key->pubkey, ED25519_PUBKEY_LEN); + + int r = crypto_pk_private_sign(onion_key, + (char*)signature, sizeof(signature), + (const char*)signed_data, sizeof(signed_data)); + if (r < 0) + return NULL; + + *len_out = r; + + return tor_memdup(signature, r); +} + +void +routerkeys_free_all(void) +{ + ed25519_keypair_free(master_identity_key); + ed25519_keypair_free(master_signing_key); + ed25519_keypair_free(current_auth_key); + tor_cert_free(signing_key_cert); + tor_cert_free(link_cert_cert); + tor_cert_free(auth_key_cert); + tor_free(rsa_ed_crosscert); + + master_identity_key = master_signing_key = NULL; + current_auth_key = NULL; + signing_key_cert = link_cert_cert = auth_key_cert = NULL; + rsa_ed_crosscert = NULL; // redundant + rsa_ed_crosscert_len = 0; +}

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[tor/maint-0.3.5] Merge remote-tracking branch 'tor-github/pr/848' into maint-0.3.5
by teor＠torproject.org 12 Aug '19

12 Aug '19

commit 3287cae68c8e6f2f72967bf6fb07e601792ecd2c Merge: a57e168ca 669ec6432 Author: teor <teor(a)torproject.org> Date: Mon Aug 12 09:38:46 2019 +1000 Merge remote-tracking branch 'tor-github/pr/848' into maint-0.3.5 changes/cid1444119 | 3 +++ src/feature/dircommon/consdiff.c | 2 +- 2 files changed, 4 insertions(+), 1 deletion(-) diff --cc src/feature/dircommon/consdiff.c index 785205cb6,000000000..d0f7594ce mode 100644,000000..100644 --- a/src/feature/dircommon/consdiff.c +++ b/src/feature/dircommon/consdiff.c @@@ -1,1414 -1,0 +1,1414 @@@ +/* Copyright (c) 2014, Daniel Martí + * Copyright (c) 2014-2019, The Tor Project, Inc. */ +/* See LICENSE for licensing information */ + +/** + * \file consdiff.c + * \brief Consensus diff implementation, including both the generation and the + * application of diffs in a minimal ed format. + * + * The consensus diff application is done in consdiff_apply_diff, which relies + * on apply_ed_diff for the main ed diff part and on some digest helper + * functions to check the digest hashes found in the consensus diff header. + * + * The consensus diff generation is more complex. consdiff_gen_diff generates + * it, relying on gen_ed_diff to generate the ed diff and some digest helper + * functions to generate the digest hashes. + * + * gen_ed_diff is the tricky bit. In it simplest form, it will take quadratic + * time and linear space to generate an ed diff given two smartlists. As shown + * in its comment section, calling calc_changes on the entire two consensuses + * will calculate what is to be added and what is to be deleted in the diff. + * Its comment section briefly explains how it works. + * + * In our case specific to consensuses, we take advantage of the fact that + * consensuses list routers sorted by their identities. We use that + * information to avoid running calc_changes on the whole smartlists. + * gen_ed_diff will navigate through the two consensuses identity by identity + * and will send small couples of slices to calc_changes, keeping the running + * time near-linear. This is explained in more detail in the gen_ed_diff + * comments. + * + * The allocation strategy tries to save time and memory by avoiding needless + * copies. Instead of actually splitting the inputs into separate strings, we + * allocate cdline_t objects, each of which represents a line in the original + * object or in the output. We use memarea_t allocators to manage the + * temporary memory we use when generating or applying diffs. + **/ + +#define CONSDIFF_PRIVATE + +#include "core/or/or.h" +#include "feature/dircommon/consdiff.h" +#include "lib/memarea/memarea.h" +#include "feature/dirparse/ns_parse.h" + +static const char* ns_diff_version = "network-status-diff-version 1"; +static const char* hash_token = "hash"; + +static char *consensus_join_lines(const smartlist_t *inp); + +/** Return true iff a and b have the same contents. */ +STATIC int +lines_eq(const cdline_t *a, const cdline_t *b) +{ + return a->len == b->len && fast_memeq(a->s, b->s, a->len); +} + +/** Return true iff a has the same contents as the nul-terminated string b. */ +STATIC int +line_str_eq(const cdline_t *a, const char *b) +{ + const size_t len = strlen(b); + tor_assert(len <= UINT32_MAX); + cdline_t bline = { b, (uint32_t)len }; + return lines_eq(a, &bline); +} + +/** Return true iff a begins with the same contents as the nul-terminated + * string b. */ +static int +line_starts_with_str(const cdline_t *a, const char *b) +{ + const size_t len = strlen(b); + tor_assert(len <= UINT32_MAX); + return a->len >= len && fast_memeq(a->s, b, len); +} + +/** Return a new cdline_t holding as its contents the nul-terminated + * string s. Use the provided memory area for storage. */ +static cdline_t * +cdline_linecpy(memarea_t *area, const char *s) +{ + size_t len = strlen(s); + const char *ss = memarea_memdup(area, s, len); + cdline_t *line = memarea_alloc(area, sizeof(cdline_t)); + line->s = ss; + line->len = (uint32_t)len; + return line; +} + +/** Add a cdline_t to lst holding as its contents the nul-terminated + * string s. Use the provided memory area for storage. */ +STATIC void +smartlist_add_linecpy(smartlist_t *lst, memarea_t *area, const char *s) +{ + smartlist_add(lst, cdline_linecpy(area, s)); +} + +/** Compute the digest of cons, and store the result in + * digest_out. Return 0 on success, -1 on failure. */ +/* This is a separate, mockable function so that we can override it when + * fuzzing. */ +MOCK_IMPL(STATIC int, +consensus_compute_digest,(const char *cons, + consensus_digest_t *digest_out)) +{ + int r = crypto_digest256((char*)digest_out->sha3_256, + cons, strlen(cons), DIGEST_SHA3_256); + return r; +} + +/** Compute the digest-as-signed of cons, and store the result in + * digest_out. Return 0 on success, -1 on failure. */ +/* This is a separate, mockable function so that we can override it when + * fuzzing. */ +MOCK_IMPL(STATIC int, +consensus_compute_digest_as_signed,(const char *cons, + consensus_digest_t *digest_out)) +{ + return router_get_networkstatus_v3_sha3_as_signed(digest_out->sha3_256, + cons); +} + +/** Return true iff d1 and d2 contain the same digest */ +/* This is a separate, mockable function so that we can override it when + * fuzzing. */ +MOCK_IMPL(STATIC int, +consensus_digest_eq,(const uint8_t *d1, + const uint8_t *d2)) +{ + return fast_memeq(d1, d2, DIGEST256_LEN); +} + +/** Create (allocate) a new slice from a smartlist. Assumes that the start + * and the end indexes are within the bounds of the initial smartlist. The end + * element is not part of the resulting slice. If end is -1, the slice is to + * reach the end of the smartlist. + */ +STATIC smartlist_slice_t * +smartlist_slice(const smartlist_t *list, int start, int end) +{ + int list_len = smartlist_len(list); + tor_assert(start >= 0); + tor_assert(start <= list_len); + if (end == -1) { + end = list_len; + } + tor_assert(start <= end); + + smartlist_slice_t *slice = tor_malloc(sizeof(smartlist_slice_t)); + slice->list = list; + slice->offset = start; + slice->len = end - start; + return slice; +} + +/** Helper: Compute the longest common subsequence lengths for the two slices. + * Used as part of the diff generation to find the column at which to split + * slice2 while still having the optimal solution. + * If direction is -1, the navigation is reversed. Otherwise it must be 1. + * The length of the resulting integer array is that of the second slice plus + * one. + */ +STATIC int * +lcs_lengths(const smartlist_slice_t *slice1, const smartlist_slice_t *slice2, + int direction) +{ + size_t a_size = sizeof(int) * (slice2->len+1); + + /* Resulting lcs lengths. */ + int *result = tor_malloc_zero(a_size); + /* Copy of the lcs lengths from the last iteration. */ + int *prev = tor_malloc(a_size); + + tor_assert(direction == 1 || direction == -1); + + int si = slice1->offset; + if (direction == -1) { + si += (slice1->len-1); + } + + for (int i = 0; i < slice1->len; ++i, si+=direction) { + + const cdline_t *line1 = smartlist_get(slice1->list, si); + /* Store the last results. */ + memcpy(prev, result, a_size); + + int sj = slice2->offset; + if (direction == -1) { + sj += (slice2->len-1); + } + + for (int j = 0; j < slice2->len; ++j, sj+=direction) { + + const cdline_t *line2 = smartlist_get(slice2->list, sj); + if (lines_eq(line1, line2)) { + /* If the lines are equal, the lcs is one line longer. */ + result[j + 1] = prev[j] + 1; + } else { + /* If not, see what lcs parent path is longer. */ + result[j + 1] = MAX(result[j], prev[j + 1]); + } + } + } + tor_free(prev); + return result; +} + +/** Helper: Trim any number of lines that are equally at the start or the end + * of both slices. + */ +STATIC void +trim_slices(smartlist_slice_t *slice1, smartlist_slice_t *slice2) +{ + while (slice1->len>0 && slice2->len>0) { + const cdline_t *line1 = smartlist_get(slice1->list, slice1->offset); + const cdline_t *line2 = smartlist_get(slice2->list, slice2->offset); + if (!lines_eq(line1, line2)) { + break; + } + slice1->offset++; slice1->len--; + slice2->offset++; slice2->len--; + } + + int i1 = (slice1->offset+slice1->len)-1; + int i2 = (slice2->offset+slice2->len)-1; + + while (slice1->len>0 && slice2->len>0) { + const cdline_t *line1 = smartlist_get(slice1->list, i1); + const cdline_t *line2 = smartlist_get(slice2->list, i2); + if (!lines_eq(line1, line2)) { + break; + } + i1--; + slice1->len--; + i2--; + slice2->len--; + } +} + +/** Like smartlist_string_pos, but uses a cdline_t, and is restricted to the + * bounds of the slice. + */ +STATIC int +smartlist_slice_string_pos(const smartlist_slice_t *slice, + const cdline_t *string) +{ + int end = slice->offset + slice->len; + for (int i = slice->offset; i < end; ++i) { + const cdline_t *el = smartlist_get(slice->list, i); + if (lines_eq(el, string)) { + return i; + } + } + return -1; +} + +/** Helper: Set all the appropriate changed booleans to true. The first slice + * must be of length 0 or 1. All the lines of slice1 and slice2 which are not + * present in the other slice will be set to changed in their bool array. + * The two changed bool arrays are passed in the same order as the slices. + */ +STATIC void +set_changed(bitarray_t *changed1, bitarray_t *changed2, + const smartlist_slice_t *slice1, const smartlist_slice_t *slice2) +{ + int toskip = -1; + tor_assert(slice1->len == 0 || slice1->len == 1); + + if (slice1->len == 1) { + const cdline_t *line_common = smartlist_get(slice1->list, slice1->offset); + toskip = smartlist_slice_string_pos(slice2, line_common); + if (toskip == -1) { + bitarray_set(changed1, slice1->offset); + } + } + int end = slice2->offset + slice2->len; + for (int i = slice2->offset; i < end; ++i) { + if (i != toskip) { + bitarray_set(changed2, i); + } + } +} + +/* + * Helper: Given that slice1 has been split by half into top and bot, we want + * to fetch the column at which to split slice2 so that we are still on track + * to the optimal diff solution, i.e. the shortest one. We use lcs_lengths + * since the shortest diff is just another way to say the longest common + * subsequence. + */ +static int +optimal_column_to_split(const smartlist_slice_t *top, + const smartlist_slice_t *bot, + const smartlist_slice_t *slice2) +{ + int *lens_top = lcs_lengths(top, slice2, 1); + int *lens_bot = lcs_lengths(bot, slice2, -1); + int column=0, max_sum=-1; + + for (int i = 0; i < slice2->len+1; ++i) { + int sum = lens_top[i] + lens_bot[slice2->len-i]; + if (sum > max_sum) { + column = i; + max_sum = sum; + } + } + tor_free(lens_top); + tor_free(lens_bot); + + return column; +} + +/** + * Helper: Figure out what elements are new or gone on the second smartlist + * relative to the first smartlist, and store the booleans in the bitarrays. + * True on the first bitarray means the element is gone, true on the second + * bitarray means it's new. + * + * In its base case, either of the smartlists is of length <= 1 and we can + * quickly see what elements are new or are gone. In the other case, we will + * split one smartlist by half and we'll use optimal_column_to_split to find + * the optimal column at which to split the second smartlist so that we are + * finding the smallest diff possible. + */ +STATIC void +calc_changes(smartlist_slice_t *slice1, + smartlist_slice_t *slice2, + bitarray_t *changed1, bitarray_t *changed2) +{ + trim_slices(slice1, slice2); + + if (slice1->len <= 1) { + set_changed(changed1, changed2, slice1, slice2); + + } else if (slice2->len <= 1) { + set_changed(changed2, changed1, slice2, slice1); + + /* Keep on splitting the slices in two. */ + } else { + smartlist_slice_t *top, *bot, *left, *right; + + /* Split the first slice in half. */ + int mid = slice1->len/2; + top = smartlist_slice(slice1->list, slice1->offset, slice1->offset+mid); + bot = smartlist_slice(slice1->list, slice1->offset+mid, + slice1->offset+slice1->len); + + /* Split the second slice by the optimal column. */ + int mid2 = optimal_column_to_split(top, bot, slice2); + left = smartlist_slice(slice2->list, slice2->offset, slice2->offset+mid2); + right = smartlist_slice(slice2->list, slice2->offset+mid2, + slice2->offset+slice2->len); + + calc_changes(top, left, changed1, changed2); + calc_changes(bot, right, changed1, changed2); + tor_free(top); + tor_free(bot); + tor_free(left); + tor_free(right); + } +} + +/* This table is from crypto.c. The SP and PAD defines are different. */ +#define NOT_VALID_BASE64 255 +#define X NOT_VALID_BASE64 +#define SP NOT_VALID_BASE64 +#define PAD NOT_VALID_BASE64 +static const uint8_t base64_compare_table[256] = { + X, X, X, X, X, X, X, X, X, SP, SP, SP, X, SP, X, X, + X, X, X, X, X, X, X, X, X, X, X, X, X, X, X, X, + SP, X, X, X, X, X, X, X, X, X, X, 62, X, X, X, 63, + 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, X, X, X, PAD, X, X, + X, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, + 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, X, X, X, X, X, + X, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, + 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, X, X, X, X, X, + X, X, X, X, X, X, X, X, X, X, X, X, X, X, X, X, + X, X, X, X, X, X, X, X, X, X, X, X, X, X, X, X, + X, X, X, X, X, X, X, X, X, X, X, X, X, X, X, X, + X, X, X, X, X, X, X, X, X, X, X, X, X, X, X, X, + X, X, X, X, X, X, X, X, X, X, X, X, X, X, X, X, + X, X, X, X, X, X, X, X, X, X, X, X, X, X, X, X, + X, X, X, X, X, X, X, X, X, X, X, X, X, X, X, X, + X, X, X, X, X, X, X, X, X, X, X, X, X, X, X, X, +}; + +/** Helper: Get the identity hash from a router line, assuming that the line + * at least appears to be a router line and thus starts with "r ". + * + * If an identity hash is found, store it (without decoding it) in + * hash_out, and return 0. On failure, return -1. + */ +STATIC int +get_id_hash(const cdline_t *line, cdline_t *hash_out) +{ + if (line->len < 2) + return -1; + + /* Skip the router name. */ + const char *hash = memchr(line->s + 2, ' ', line->len - 2); + if (!hash) { + return -1; + } + + hash++; + const char *hash_end = hash; + /* Stop when the first non-base64 character is found. Use unsigned chars to + * avoid negative indexes causing crashes. + */ + while (base64_compare_table[*((unsigned char*)hash_end)] + != NOT_VALID_BASE64 && + hash_end < line->s + line->len) { + hash_end++; + } + + /* Empty hash. */ + if (hash_end == hash) { + return -1; + } + + hash_out->s = hash; + /* Always true because lines are limited to this length */ + tor_assert(hash_end >= hash); + tor_assert((size_t)(hash_end - hash) <= UINT32_MAX); + hash_out->len = (uint32_t)(hash_end - hash); + + return 0; +} + +/** Helper: Check that a line is a valid router entry. We must at least be + * able to fetch a proper identity hash from it for it to be valid. + */ +STATIC int +is_valid_router_entry(const cdline_t *line) +{ + if (line->len < 2 || fast_memneq(line->s, "r ", 2)) + return 0; + cdline_t tmp; + return (get_id_hash(line, &tmp) == 0); +} + +/** Helper: Find the next router line starting at the current position. + * Assumes that cur is lower than the length of the smartlist, i.e. it is a + * line within the bounds of the consensus. The only exception is when we + * don't want to skip the first line, in which case cur will be -1. + */ +STATIC int +next_router(const smartlist_t *cons, int cur) +{ + int len = smartlist_len(cons); + tor_assert(cur >= -1 && cur < len); + + if (++cur >= len) { + return len; + } + + const cdline_t *line = smartlist_get(cons, cur); + while (!is_valid_router_entry(line)) { + if (++cur >= len) { + return len; + } + line = smartlist_get(cons, cur); + } + return cur; +} + +/** Helper: compare two base64-encoded identity hashes, which may be of + * different lengths. Comparison ends when the first non-base64 char is found. + */ +STATIC int +base64cmp(const cdline_t *hash1, const cdline_t *hash2) +{ + /* NULL is always lower, useful for last_hash which starts at NULL. */ + if (!hash1->s && !hash2->s) { + return 0; + } + if (!hash1->s) { + return -1; + } + if (!hash2->s) { + return 1; + } + + /* Don't index with a char; char may be signed. */ + const unsigned char *a = (unsigned char*)hash1->s; + const unsigned char *b = (unsigned char*)hash2->s; + const unsigned char *a_end = a + hash1->len; + const unsigned char *b_end = b + hash2->len; + while (1) { + uint8_t av = base64_compare_table[*a]; + uint8_t bv = base64_compare_table[*b]; + if (av == NOT_VALID_BASE64) { + if (bv == NOT_VALID_BASE64) { + /* Both ended with exactly the same characters. */ + return 0; + } else { + /* hash2 goes on longer than hash1 and thus hash1 is lower. */ + return -1; + } + } else if (bv == NOT_VALID_BASE64) { + /* hash1 goes on longer than hash2 and thus hash1 is greater. */ + return 1; + } else if (av < bv) { + /* The first difference shows that hash1 is lower. */ + return -1; + } else if (av > bv) { + /* The first difference shows that hash1 is greater. */ + return 1; + } else { + a++; + b++; + if (a == a_end) { + if (b == b_end) { + return 0; + } else { + return -1; + } + } else if (b == b_end) { + return 1; + } + } + } +} + +/** Structure used to remember the previous and current identity hash of + * the "r " lines in a consensus, to enforce well-ordering. */ +typedef struct router_id_iterator_t { + cdline_t last_hash; + cdline_t hash; +} router_id_iterator_t; + +/** + * Initializer for a router_id_iterator_t. + */ +#define ROUTER_ID_ITERATOR_INIT { { NULL, 0 }, { NULL, 0 } } + +/** Given an index *idxp into the consensus at cons, advance + * the index to the next router line ("r ...") in the consensus, or to + * an index one after the end of the list if there is no such line. + * + * Use iter to record the hash of the found router line, if any, + * and to enforce ordering on the hashes. If the hashes are mis-ordered, + * return -1. Else, return 0. + **/ +static int +find_next_router_line(const smartlist_t *cons, + const char *consname, + int *idxp, + router_id_iterator_t *iter) +{ + *idxp = next_router(cons, *idxp); + if (*idxp < smartlist_len(cons)) { + memcpy(&iter->last_hash, &iter->hash, sizeof(cdline_t)); + if (get_id_hash(smartlist_get(cons, *idxp), &iter->hash) < 0 || + base64cmp(&iter->hash, &iter->last_hash) <= 0) { + log_warn(LD_CONSDIFF, "Refusing to generate consensus diff because " + "the %s consensus doesn't have its router entries sorted " + "properly.", consname); + return -1; + } + } + return 0; +} + +/** Line-prefix indicating the beginning of the signatures section that we + * intend to delete. */ +#define START_OF_SIGNATURES_SECTION "directory-signature " + +/** Pre-process a consensus in cons (represented as a list of cdline_t) + * to remove the signatures from it. If the footer is removed, return a + * cdline_t containing a delete command to delete the footer, allocated in + * area</>. If no footer is removed, return NULL. + * + * We remove the signatures here because they are not themselves signed, and + * as such there might be different encodings for them. + */ +static cdline_t * +preprocess_consensus(memarea_t *area, + smartlist_t *cons) +{ + int idx; + int dirsig_idx = -1; + for (idx = 0; idx < smartlist_len(cons); ++idx) { + cdline_t *line = smartlist_get(cons, idx); + if (line_starts_with_str(line, START_OF_SIGNATURES_SECTION)) { + dirsig_idx = idx; + break; + } + } + if (dirsig_idx >= 0) { + char buf[64]; + while (smartlist_len(cons) > dirsig_idx) + smartlist_del(cons, dirsig_idx); + tor_snprintf(buf, sizeof(buf), "%d,$d", dirsig_idx+1); + return cdline_linecpy(area, buf); + } else { + return NULL; + } +} + +/** Generate an ed diff as a smartlist from two consensuses, also given as + * smartlists. Will return NULL if the diff could not be generated, which can + * happen if any lines the script had to add matched "." or if the routers + * were not properly ordered. + * + * All cdline_t objects in the resulting object are either references to lines + * in one of the inputs, or are newly allocated lines in the provided memarea. + * + * This implementation is consensus-specific. To generate an ed diff for any + * given input in quadratic time, you can replace all the code until the + * navigation in reverse order with the following: + * + * int len1 = smartlist_len(cons1); + * int len2 = smartlist_len(cons2); + * bitarray_t *changed1 = bitarray_init_zero(len1); + * bitarray_t *changed2 = bitarray_init_zero(len2); + * cons1_sl = smartlist_slice(cons1, 0, -1); + * cons2_sl = smartlist_slice(cons2, 0, -1); + * calc_changes(cons1_sl, cons2_sl, changed1, changed2); + */ +STATIC smartlist_t * +gen_ed_diff(const smartlist_t *cons1_orig, const smartlist_t *cons2, + memarea_t *area) +{ + smartlist_t *cons1 = smartlist_new(); + smartlist_add_all(cons1, cons1_orig); + cdline_t *remove_trailer = preprocess_consensus(area, cons1); + + int len1 = smartlist_len(cons1); + int len2 = smartlist_len(cons2); + smartlist_t *result = smartlist_new(); + + if (remove_trailer) { + /* There's a delete-the-trailer line at the end, so add it here. */ + smartlist_add(result, remove_trailer); + } + + /* Initialize the changed bitarrays to zero, so that calc_changes only needs + * to set the ones that matter and leave the rest untouched. + */ + bitarray_t *changed1 = bitarray_init_zero(len1); + bitarray_t *changed2 = bitarray_init_zero(len2); + int i1=-1, i2=-1; + int start1=0, start2=0; + + /* To check that hashes are ordered properly */ + router_id_iterator_t iter1 = ROUTER_ID_ITERATOR_INIT; + router_id_iterator_t iter2 = ROUTER_ID_ITERATOR_INIT; + + /* i1 and i2 are initialized at the first line of each consensus. They never + * reach past len1 and len2 respectively, since next_router doesn't let that + * happen. i1 and i2 are advanced by at least one line at each iteration as + * long as they have not yet reached len1 and len2, so the loop is + * guaranteed to end, and each pair of (i1,i2) will be inspected at most + * once. + */ + while (i1 < len1 || i2 < len2) { + + /* Advance each of the two navigation positions by one router entry if not + * yet at the end. + */ + if (i1 < len1) { + if (find_next_router_line(cons1, "base", &i1, &iter1) < 0) { + goto error_cleanup; + } + } + + if (i2 < len2) { + if (find_next_router_line(cons2, "target", &i2, &iter2) < 0) { + goto error_cleanup; + } + } + + /* If we have reached the end of both consensuses, there is no need to + * compare hashes anymore, since this is the last iteration. + */ + if (i1 < len1 || i2 < len2) { + + /* Keep on advancing the lower (by identity hash sorting) position until + * we have two matching positions. The only other possible outcome is + * that a lower position reaches the end of the consensus before it can + * reach a hash that is no longer the lower one. Since there will always + * be a lower hash for as long as the loop runs, one of the two indexes + * will always be incremented, thus assuring that the loop must end + * after a finite number of iterations. If that cannot be because said + * consensus has already reached the end, both are extended to their + * respecting ends since we are done. + */ + int cmp = base64cmp(&iter1.hash, &iter2.hash); + while (cmp != 0) { + if (i1 < len1 && cmp < 0) { + if (find_next_router_line(cons1, "base", &i1, &iter1) < 0) { + goto error_cleanup; + } + if (i1 == len1) { + /* We finished the first consensus, so grab all the remaining + * lines of the second consensus and finish up. + */ + i2 = len2; + break; + } + } else if (i2 < len2 && cmp > 0) { + if (find_next_router_line(cons2, "target", &i2, &iter2) < 0) { + goto error_cleanup; + } + if (i2 == len2) { + /* We finished the second consensus, so grab all the remaining + * lines of the first consensus and finish up. + */ + i1 = len1; + break; + } + } else { + i1 = len1; + i2 = len2; + break; + } + cmp = base64cmp(&iter1.hash, &iter2.hash); + } + } + + /* Make slices out of these chunks (up to the common router entry) and + * calculate the changes for them. + * Error if any of the two slices are longer than 10K lines. That should + * never happen with any pair of real consensuses. Feeding more than 10K + * lines to calc_changes would be very slow anyway. + */ +#define MAX_LINE_COUNT (10000) + if (i1-start1 > MAX_LINE_COUNT || i2-start2 > MAX_LINE_COUNT) { + log_warn(LD_CONSDIFF, "Refusing to generate consensus diff because " + "we found too few common router ids."); + goto error_cleanup; + } + + smartlist_slice_t *cons1_sl = smartlist_slice(cons1, start1, i1); + smartlist_slice_t *cons2_sl = smartlist_slice(cons2, start2, i2); + calc_changes(cons1_sl, cons2_sl, changed1, changed2); + tor_free(cons1_sl); + tor_free(cons2_sl); + start1 = i1, start2 = i2; + } + + /* Navigate the changes in reverse order and generate one ed command for + * each chunk of changes. + */ + i1=len1-1, i2=len2-1; + char buf[128]; + while (i1 >= 0 || i2 >= 0) { + + int start1x, start2x, end1, end2, added, deleted; + + /* We are at a point were no changed bools are true, so just keep going. */ + if (!(i1 >= 0 && bitarray_is_set(changed1, i1)) && + !(i2 >= 0 && bitarray_is_set(changed2, i2))) { + if (i1 >= 0) { + i1--; + } + if (i2 >= 0) { + i2--; + } + continue; + } + + end1 = i1, end2 = i2; + + /* Grab all contiguous changed lines */ + while (i1 >= 0 && bitarray_is_set(changed1, i1)) { + i1--; + } + while (i2 >= 0 && bitarray_is_set(changed2, i2)) { + i2--; + } + + start1x = i1+1, start2x = i2+1; + added = end2-i2, deleted = end1-i1; + + if (added == 0) { + if (deleted == 1) { + tor_snprintf(buf, sizeof(buf), "%id", start1x+1); + smartlist_add_linecpy(result, area, buf); + } else { + tor_snprintf(buf, sizeof(buf), "%i,%id", start1x+1, start1x+deleted); + smartlist_add_linecpy(result, area, buf); + } + } else { + int i; + if (deleted == 0) { + tor_snprintf(buf, sizeof(buf), "%ia", start1x); + smartlist_add_linecpy(result, area, buf); + } else if (deleted == 1) { + tor_snprintf(buf, sizeof(buf), "%ic", start1x+1); + smartlist_add_linecpy(result, area, buf); + } else { + tor_snprintf(buf, sizeof(buf), "%i,%ic", start1x+1, start1x+deleted); + smartlist_add_linecpy(result, area, buf); + } + + for (i = start2x; i <= end2; ++i) { + cdline_t *line = smartlist_get(cons2, i); + if (line_str_eq(line, ".")) { + log_warn(LD_CONSDIFF, "Cannot generate consensus diff because " + "one of the lines to be added is \".\"."); + goto error_cleanup; + } + smartlist_add(result, line); + } + smartlist_add_linecpy(result, area, "."); + } + } + + smartlist_free(cons1); + bitarray_free(changed1); + bitarray_free(changed2); + + return result; + + error_cleanup: + + smartlist_free(cons1); + bitarray_free(changed1); + bitarray_free(changed2); + + smartlist_free(result); + + return NULL; +} + +/* Helper: Read a base-10 number between 0 and INT32_MAX from s and + * store it in num_out. Advance s to the characer immediately + * after the number. Return 0 on success, -1 on failure. */ +static int +get_linenum(const char **s, int *num_out) +{ + int ok; + char *next; + if (!TOR_ISDIGIT(**s)) { + return -1; + } + *num_out = (int) tor_parse_long(*s, 10, 0, INT32_MAX, &ok, &next); + if (ok && next) { + *s = next; + return 0; + } else { + return -1; + } +} + +/** Apply the ed diff, starting at diff_starting_line, to the consensus + * and return a new consensus, also as a line-based smartlist. Will return + * NULL if the ed diff is not properly formatted. + * + * All cdline_t objects in the resulting object are references to lines + * in one of the inputs; nothing is copied. + */ +STATIC smartlist_t * +apply_ed_diff(const smartlist_t *cons1, const smartlist_t *diff, + int diff_starting_line) +{ + int diff_len = smartlist_len(diff); + int j = smartlist_len(cons1); + smartlist_t *cons2 = smartlist_new(); + + for (int i=diff_starting_line; i<diff_len; ++i) { + const cdline_t *diff_cdline = smartlist_get(diff, i); + char diff_line[128]; + + if (diff_cdline->len > sizeof(diff_line) - 1) { + log_warn(LD_CONSDIFF, "Could not apply consensus diff because " + "an ed command was far too long"); + goto error_cleanup; + } + /* Copy the line to make it nul-terminated. */ + memcpy(diff_line, diff_cdline->s, diff_cdline->len); + diff_line[diff_cdline->len] = 0; + const char *ptr = diff_line; + int start = 0, end = 0; + int had_range = 0; + int end_was_eof = 0; + if (get_linenum(&ptr, &start) < 0) { + log_warn(LD_CONSDIFF, "Could not apply consensus diff because " + "an ed command was missing a line number."); + goto error_cleanup; + } + if (*ptr == ',') { + /* Two-item range */ + had_range = 1; + ++ptr; + if (*ptr == '$') { + end_was_eof = 1; + end = smartlist_len(cons1); + ++ptr; + } else if (get_linenum(&ptr, &end) < 0) { + log_warn(LD_CONSDIFF, "Could not apply consensus diff because " + "an ed command was missing a range end line number."); + goto error_cleanup; + } + /* Incoherent range. */ + if (end <= start) { + log_warn(LD_CONSDIFF, "Could not apply consensus diff because " + "an invalid range was found in an ed command."); + goto error_cleanup; + } + } else { + /* We'll take <n1> as <n1>,<n1> for simplicity. */ + end = start; + } + + if (end > j) { + log_warn(LD_CONSDIFF, "Could not apply consensus diff because " + "its commands are not properly sorted in reverse order."); + goto error_cleanup; + } + + if (*ptr == '\0') { + log_warn(LD_CONSDIFF, "Could not apply consensus diff because " + "a line with no ed command was found"); + goto error_cleanup; + } + + if (*(ptr+1) != '\0') { + log_warn(LD_CONSDIFF, "Could not apply consensus diff because " + "an ed command longer than one char was found."); + goto error_cleanup; + } + + char action = *ptr; + + switch (action) { + case 'a': + case 'c': + case 'd': + break; + default: + log_warn(LD_CONSDIFF, "Could not apply consensus diff because " + "an unrecognised ed command was found."); + goto error_cleanup; + } + + /** $ is not allowed with non-d actions. */ + if (end_was_eof && action != 'd') { + log_warn(LD_CONSDIFF, "Could not apply consensus diff because " + "it wanted to use $ with a command other than delete"); + goto error_cleanup; + } + + /* 'a' commands are not allowed to have ranges. */ + if (had_range && action == 'a') { + log_warn(LD_CONSDIFF, "Could not apply consensus diff because " + "it wanted to add lines after a range."); + goto error_cleanup; + } + + /* Add unchanged lines. */ + for (; j && j > end; --j) { + cdline_t *cons_line = smartlist_get(cons1, j-1); + smartlist_add(cons2, cons_line); + } + + /* Ignore removed lines. */ + if (action == 'c' || action == 'd') { + while (--j >= start) { + /* Skip line */ + } + } + + /* Add new lines in reverse order, since it will all be reversed at the + * end. + */ + if (action == 'a' || action == 'c') { + int added_end = i; + + i++; /* Skip the line with the range and command. */ + while (i < diff_len) { + if (line_str_eq(smartlist_get(diff, i), ".")) { + break; + } + if (++i == diff_len) { + log_warn(LD_CONSDIFF, "Could not apply consensus diff because " + "it has lines to be inserted that don't end with a \".\"."); + goto error_cleanup; + } + } + + int added_i = i-1; + + /* It would make no sense to add zero new lines. */ + if (added_i == added_end) { + log_warn(LD_CONSDIFF, "Could not apply consensus diff because " + "it has an ed command that tries to insert zero lines."); + goto error_cleanup; + } + + while (added_i > added_end) { + cdline_t *added_line = smartlist_get(diff, added_i--); + smartlist_add(cons2, added_line); + } + } + } + + /* Add remaining unchanged lines. */ + for (; j > 0; --j) { + cdline_t *cons_line = smartlist_get(cons1, j-1); + smartlist_add(cons2, cons_line); + } + + /* Reverse the whole thing since we did it from the end. */ + smartlist_reverse(cons2); + return cons2; + + error_cleanup: + + smartlist_free(cons2); + + return NULL; +} + +/** Generate a consensus diff as a smartlist from two given consensuses, also + * as smartlists. Will return NULL if the consensus diff could not be + * generated. Neither of the two consensuses are modified in any way, so it's + * up to the caller to free their resources. + */ +smartlist_t * +consdiff_gen_diff(const smartlist_t *cons1, + const smartlist_t *cons2, + const consensus_digest_t *digests1, + const consensus_digest_t *digests2, + memarea_t *area) +{ + smartlist_t *ed_diff = gen_ed_diff(cons1, cons2, area); + /* ed diff could not be generated - reason already logged by gen_ed_diff. */ + if (!ed_diff) { + goto error_cleanup; + } + + /* See that the script actually produces what we want. */ + smartlist_t *ed_cons2 = apply_ed_diff(cons1, ed_diff, 0); + if (!ed_cons2) { + /* LCOV_EXCL_START -- impossible if diff generation is correct */ + log_warn(LD_BUG|LD_CONSDIFF, "Refusing to generate consensus diff because " + "the generated ed diff could not be tested to successfully generate " + "the target consensus."); + goto error_cleanup; + /* LCOV_EXCL_STOP */ + } + + int cons2_eq = 1; + if (smartlist_len(cons2) == smartlist_len(ed_cons2)) { + SMARTLIST_FOREACH_BEGIN(cons2, const cdline_t *, line1) { + const cdline_t *line2 = smartlist_get(ed_cons2, line1_sl_idx); + if (! lines_eq(line1, line2) ) { + cons2_eq = 0; + break; + } + } SMARTLIST_FOREACH_END(line1); + } else { + cons2_eq = 0; + } + smartlist_free(ed_cons2); + if (!cons2_eq) { + /* LCOV_EXCL_START -- impossible if diff generation is correct. */ + log_warn(LD_BUG|LD_CONSDIFF, "Refusing to generate consensus diff because " + "the generated ed diff did not generate the target consensus " + "successfully when tested."); + goto error_cleanup; + /* LCOV_EXCL_STOP */ + } + + char cons1_hash_hex[HEX_DIGEST256_LEN+1]; + char cons2_hash_hex[HEX_DIGEST256_LEN+1]; + base16_encode(cons1_hash_hex, HEX_DIGEST256_LEN+1, + (const char*)digests1->sha3_256, DIGEST256_LEN); + base16_encode(cons2_hash_hex, HEX_DIGEST256_LEN+1, + (const char*)digests2->sha3_256, DIGEST256_LEN); + + /* Create the resulting consensus diff. */ + char buf[160]; + smartlist_t *result = smartlist_new(); + tor_snprintf(buf, sizeof(buf), "%s", ns_diff_version); + smartlist_add_linecpy(result, area, buf); + tor_snprintf(buf, sizeof(buf), "%s %s %s", hash_token, + cons1_hash_hex, cons2_hash_hex); + smartlist_add_linecpy(result, area, buf); + smartlist_add_all(result, ed_diff); + smartlist_free(ed_diff); + return result; + + error_cleanup: + + if (ed_diff) { + /* LCOV_EXCL_START -- ed_diff is NULL except in unreachable cases above */ + smartlist_free(ed_diff); + /* LCOV_EXCL_STOP */ + } + + return NULL; +} + +/** Fetch the digest of the base consensus in the consensus diff, encoded in + * base16 as found in the diff itself. digest1_out and digest2_out must be of + * length DIGEST256_LEN or larger if not NULL. + */ +int +consdiff_get_digests(const smartlist_t *diff, + char *digest1_out, + char *digest2_out) +{ + smartlist_t *hash_words = NULL; + const cdline_t *format; + char cons1_hash[DIGEST256_LEN], cons2_hash[DIGEST256_LEN]; + char *cons1_hash_hex, *cons2_hash_hex; + if (smartlist_len(diff) < 2) { + log_info(LD_CONSDIFF, "The provided consensus diff is too short."); + goto error_cleanup; + } + + /* Check that it's the format and version we know. */ + format = smartlist_get(diff, 0); + if (!line_str_eq(format, ns_diff_version)) { + log_warn(LD_CONSDIFF, "The provided consensus diff format is not known."); + goto error_cleanup; + } + + /* Grab the base16 digests. */ + hash_words = smartlist_new(); + { + const cdline_t *line2 = smartlist_get(diff, 1); + char *h = tor_memdup_nulterm(line2->s, line2->len); + smartlist_split_string(hash_words, h, " ", 0, 0); + tor_free(h); + } + + /* There have to be three words, the first of which must be hash_token. */ + if (smartlist_len(hash_words) != 3 || + strcmp(smartlist_get(hash_words, 0), hash_token)) { + log_info(LD_CONSDIFF, "The provided consensus diff does not include " + "the necessary digests."); + goto error_cleanup; + } + + /* Expected hashes as found in the consensus diff header. They must be of + * length HEX_DIGEST256_LEN, normally 64 hexadecimal characters. + * If any of the decodings fail, error to make sure that the hashes are + * proper base16-encoded digests. + */ + cons1_hash_hex = smartlist_get(hash_words, 1); + cons2_hash_hex = smartlist_get(hash_words, 2); + if (strlen(cons1_hash_hex) != HEX_DIGEST256_LEN || + strlen(cons2_hash_hex) != HEX_DIGEST256_LEN) { + log_info(LD_CONSDIFF, "The provided consensus diff includes " + "base16-encoded digests of incorrect size."); + goto error_cleanup; + } + + if (base16_decode(cons1_hash, DIGEST256_LEN, + cons1_hash_hex, HEX_DIGEST256_LEN) != DIGEST256_LEN || + base16_decode(cons2_hash, DIGEST256_LEN, + cons2_hash_hex, HEX_DIGEST256_LEN) != DIGEST256_LEN) { + log_info(LD_CONSDIFF, "The provided consensus diff includes " + "malformed digests."); + goto error_cleanup; + } + + if (digest1_out) { + memcpy(digest1_out, cons1_hash, DIGEST256_LEN); + } + if (digest2_out) { + memcpy(digest2_out, cons2_hash, DIGEST256_LEN); + } + + SMARTLIST_FOREACH(hash_words, char *, cp, tor_free(cp)); + smartlist_free(hash_words); + return 0; + + error_cleanup: + + if (hash_words) { + SMARTLIST_FOREACH(hash_words, char *, cp, tor_free(cp)); + smartlist_free(hash_words); + } + return 1; +} + +/** Apply the consensus diff to the given consensus and return a new + * consensus, also as a line-based smartlist. Will return NULL if the diff + * could not be applied. Neither the consensus nor the diff are modified in + * any way, so it's up to the caller to free their resources. + */ +char * +consdiff_apply_diff(const smartlist_t *cons1, + const smartlist_t *diff, + const consensus_digest_t *digests1) +{ + smartlist_t *cons2 = NULL; + char *cons2_str = NULL; + char e_cons1_hash[DIGEST256_LEN]; + char e_cons2_hash[DIGEST256_LEN]; + + if (consdiff_get_digests(diff, e_cons1_hash, e_cons2_hash) != 0) { + goto error_cleanup; + } + + /* See that the consensus that was given to us matches its hash. */ + if (!consensus_digest_eq(digests1->sha3_256, + (const uint8_t*)e_cons1_hash)) { + char hex_digest1[HEX_DIGEST256_LEN+1]; + char e_hex_digest1[HEX_DIGEST256_LEN+1]; + log_warn(LD_CONSDIFF, "Refusing to apply consensus diff because " + "the base consensus doesn't match the digest as found in " + "the consensus diff header."); + base16_encode(hex_digest1, HEX_DIGEST256_LEN+1, + (const char *)digests1->sha3_256, DIGEST256_LEN); + base16_encode(e_hex_digest1, HEX_DIGEST256_LEN+1, + e_cons1_hash, DIGEST256_LEN); + log_warn(LD_CONSDIFF, "Expected: %s; found: %s", + hex_digest1, e_hex_digest1); + goto error_cleanup; + } + + /* Grab the ed diff and calculate the resulting consensus. */ + /* Skip the first two lines. */ + cons2 = apply_ed_diff(cons1, diff, 2); + + /* ed diff could not be applied - reason already logged by apply_ed_diff. */ + if (!cons2) { + goto error_cleanup; + } + + cons2_str = consensus_join_lines(cons2); + + consensus_digest_t cons2_digests; + if (consensus_compute_digest(cons2_str, &cons2_digests) < 0) { + /* LCOV_EXCL_START -- digest can't fail */ + log_warn(LD_CONSDIFF, "Could not compute digests of the consensus " + "resulting from applying a consensus diff."); + goto error_cleanup; + /* LCOV_EXCL_STOP */ + } + + /* See that the resulting consensus matches its hash. */ + if (!consensus_digest_eq(cons2_digests.sha3_256, + (const uint8_t*)e_cons2_hash)) { + log_warn(LD_CONSDIFF, "Refusing to apply consensus diff because " + "the resulting consensus doesn't match the digest as found in " + "the consensus diff header."); + char hex_digest2[HEX_DIGEST256_LEN+1]; + char e_hex_digest2[HEX_DIGEST256_LEN+1]; + base16_encode(hex_digest2, HEX_DIGEST256_LEN+1, + (const char *)cons2_digests.sha3_256, DIGEST256_LEN); + base16_encode(e_hex_digest2, HEX_DIGEST256_LEN+1, + e_cons2_hash, DIGEST256_LEN); + log_warn(LD_CONSDIFF, "Expected: %s; found: %s", + hex_digest2, e_hex_digest2); + goto error_cleanup; + } + + goto done; + + error_cleanup: + tor_free(cons2_str); /* Sets it to NULL */ + + done: + if (cons2) { + smartlist_free(cons2); + } + + return cons2_str; +} + +/** Any consensus line longer than this means that the input is invalid. */ +#define CONSENSUS_LINE_MAX_LEN (1<<20) + +/** + * Helper: For every NL-terminated line in s, add a cdline referring to + * that line (without trailing newline) to out. Return -1 if there are + * any non-NL terminated lines; 0 otherwise. + * + * Unlike tor_split_lines, this function avoids ambiguity on its + * handling of a final line that isn't NL-terminated. + * + * All cdline_t objects are allocated in the provided memarea. Strings + * are not copied: if s changes or becomes invalid, then all + * generated cdlines will become invalid. + */ +STATIC int +consensus_split_lines(smartlist_t *out, const char *s, memarea_t *area) +{ + const char *end_of_str = s + strlen(s); + tor_assert(*end_of_str == '\0'); + + while (*s) { + const char *eol = memchr(s, '\n', end_of_str - s); + if (!eol) { + /* File doesn't end with newline. */ + return -1; + } + if (eol - s > CONSENSUS_LINE_MAX_LEN) { + /* Line is far too long. */ + return -1; + } + cdline_t *line = memarea_alloc(area, sizeof(cdline_t)); + line->s = s; + line->len = (uint32_t)(eol - s); + smartlist_add(out, line); + s = eol+1; + } + return 0; +} + +/** Given a list of cdline_t, return a newly allocated string containing + * all of the lines, terminated with NL, concatenated. + * + * Unlike smartlist_join_strings(), avoids lossy operations on empty + * lists. */ +static char * +consensus_join_lines(const smartlist_t *inp) +{ + size_t n = 0; + SMARTLIST_FOREACH(inp, const cdline_t *, cdline, n += cdline->len + 1); + n += 1; + char *result = tor_malloc(n); + char *out = result; + SMARTLIST_FOREACH_BEGIN(inp, const cdline_t *, cdline) { + memcpy(out, cdline->s, cdline->len); + out += cdline->len; + *out++ = '\n'; + } SMARTLIST_FOREACH_END(cdline); + *out++ = '\0'; + tor_assert(out == result+n); + return result; +} + +/** Given two consensus documents, try to compute a diff between them. On + * success, retun a newly allocated string containing that diff. On failure, + * return NULL. */ +char * +consensus_diff_generate(const char *cons1, + const char *cons2) +{ + consensus_digest_t d1, d2; + smartlist_t *lines1 = NULL, *lines2 = NULL, *result_lines = NULL; + int r1, r2; + char *result = NULL; + + r1 = consensus_compute_digest_as_signed(cons1, &d1); + r2 = consensus_compute_digest(cons2, &d2); + if (BUG(r1 < 0 || r2 < 0)) + return NULL; // LCOV_EXCL_LINE + + memarea_t *area = memarea_new(); + lines1 = smartlist_new(); + lines2 = smartlist_new(); + if (consensus_split_lines(lines1, cons1, area) < 0) + goto done; + if (consensus_split_lines(lines2, cons2, area) < 0) + goto done; + + result_lines = consdiff_gen_diff(lines1, lines2, &d1, &d2, area); + + done: + if (result_lines) { + result = consensus_join_lines(result_lines); + smartlist_free(result_lines); + } + + memarea_drop_all(area); + smartlist_free(lines1); + smartlist_free(lines2); + + return result; +} + +/** Given a consensus document and a diff, try to apply the diff to the + * consensus. On success return a newly allocated string containing the new + * consensus. On failure, return NULL. */ +char * +consensus_diff_apply(const char *consensus, + const char *diff) +{ + consensus_digest_t d1; + smartlist_t *lines1 = NULL, *lines2 = NULL; + int r1; + char *result = NULL; + memarea_t *area = memarea_new(); + + r1 = consensus_compute_digest_as_signed(consensus, &d1); + if (BUG(r1 < 0)) - return NULL; // LCOV_EXCL_LINE ++ goto done; + + lines1 = smartlist_new(); + lines2 = smartlist_new(); + if (consensus_split_lines(lines1, consensus, area) < 0) + goto done; + if (consensus_split_lines(lines2, diff, area) < 0) + goto done; + + result = consdiff_apply_diff(lines1, lines2, &d1); + + done: + smartlist_free(lines1); + smartlist_free(lines2); + memarea_drop_all(area); + + return result; +} + +/** Return true iff, based on its header, document is likely + * to be a consensus diff. */ +int +looks_like_a_consensus_diff(const char *document, size_t len) +{ + return (len >= strlen(ns_diff_version) && + fast_memeq(document, ns_diff_version, strlen(ns_diff_version))); +}

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[tor/maint-0.3.5] Merge remote-tracking branch 'tor-github/pr/926' into maint-0.3.5
by teor＠torproject.org 12 Aug '19

12 Aug '19

commit 9be65c440baae43dd38ffef216f6198c714ba5ba Merge: 955cf9620 2cdc6b200 Author: teor <teor(a)torproject.org> Date: Mon Aug 12 09:41:14 2019 +1000 Merge remote-tracking branch 'tor-github/pr/926' into maint-0.3.5 changes/bug30040 | 9 +++++++++ src/ext/getdelim.c | 3 ++- 2 files changed, 11 insertions(+), 1 deletion(-)

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[tor/maint-0.3.5] Merge remote-tracking branch 'tor-github/pr/911' into maint-0.3.5
by teor＠torproject.org 12 Aug '19

12 Aug '19

commit 955cf9620c68c17f6531e80f9f4a7fa7d9f0f479 Merge: 3287cae68 4dd96f744 Author: teor <teor(a)torproject.org> Date: Mon Aug 12 09:40:08 2019 +1000 Merge remote-tracking branch 'tor-github/pr/911' into maint-0.3.5 changes/29241_diagnostic | 4 ++++ changes/bug29241 | 6 ++++++ src/lib/tls/tortls_nss.c | 40 ++++++++++++++++++++++++++++++++++++++++ 3 files changed, 50 insertions(+)

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[tor/maint-0.3.5] Merge remote-tracking branch 'tor-github/pr/952' into maint-0.3.5
by teor＠torproject.org 12 Aug '19

12 Aug '19

commit 6ed56ee4eaf679d4352d034af5951d36fc9a6f8e Merge: 2d4772dc4 802ac8ad6 Author: teor <teor(a)torproject.org> Date: Mon Aug 12 09:44:46 2019 +1000 Merge remote-tracking branch 'tor-github/pr/952' into maint-0.3.5 changes/bug30189 | 4 ++++ src/lib/log/util_bug.c | 14 ++++++++++++++ src/lib/log/util_bug.h | 8 +++++--- 3 files changed, 23 insertions(+), 3 deletions(-)

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[tor/maint-0.3.5] Merge remote-tracking branch 'tor-github/pr/951' into maint-0.3.5
by teor＠torproject.org 12 Aug '19

12 Aug '19

commit 2d4772dc47e6e7c43c3909540e73a139333fc7d6 Merge: ef345ab56 8c4e68438 Author: teor <teor(a)torproject.org> Date: Mon Aug 12 09:43:37 2019 +1000 Merge remote-tracking branch 'tor-github/pr/951' into maint-0.3.5 changes/bug30190 | 3 +++ src/lib/crypt_ops/crypto_openssl_mgt.c | 8 ++++++++ 2 files changed, 11 insertions(+)

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[tor/maint-0.3.5] Merge remote-tracking branch 'tor-github/pr/1020' into maint-0.3.5
by teor＠torproject.org 12 Aug '19

12 Aug '19

commit f65f4b5c38bc79e2b3f1a10c21cedce9376ad87e Merge: 8ea090322 0c451b31d Author: teor <teor(a)torproject.org> Date: Mon Aug 12 09:49:53 2019 +1000 Merge remote-tracking branch 'tor-github/pr/1020' into maint-0.3.5 changes/bug30452 | 3 +++ doc/tor.1.txt | 4 ++++ src/app/config/config.c | 13 +++++++++++++ src/app/main/main.c | 1 + src/feature/dirauth/authmode.h | 4 ++++ 5 files changed, 25 insertions(+)

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