commit dd4fa9b46899855dec66e31a1ebf5164d5cd281c Author: Nick Mathewson nickm@torproject.org Date: Wed Feb 19 19:11:49 2020 -0500
Extract relay-only handshake code into its own file.
This is not the only relay-only handshake code, but it is most of such code that is in connection_or.c. --- scripts/maint/practracker/exceptions.txt | 4 +- src/core/or/channeltls.c | 1 + src/core/or/connection_or.c | 534 +---------------------------- src/core/or/connection_or.h | 14 - src/core/or/include.am | 2 + src/core/or/relay_handshake.c | 565 +++++++++++++++++++++++++++++++ src/core/or/relay_handshake.h | 38 +++ src/test/test_link_handshake.c | 1 + 8 files changed, 610 insertions(+), 549 deletions(-)
diff --git a/scripts/maint/practracker/exceptions.txt b/scripts/maint/practracker/exceptions.txt index d11896710..ac81c79b4 100644 --- a/scripts/maint/practracker/exceptions.txt +++ b/scripts/maint/practracker/exceptions.txt @@ -143,10 +143,9 @@ problem function-size /src/core/or/connection_edge.c:connection_exit_connect() 1 problem dependency-violation /src/core/or/connection_edge.c 27 problem dependency-violation /src/core/or/connection_edge.h 1 problem file-size /src/core/or/connection_or.c 3122 -problem include-count /src/core/or/connection_or.c 51 problem function-size /src/core/or/connection_or.c:connection_or_group_set_badness_() 105 problem function-size /src/core/or/connection_or.c:connection_or_client_learned_peer_id() 142 -problem function-size /src/core/or/connection_or.c:connection_or_compute_authenticate_cell_body() 231 +problem function-size /src/core/or/relay_handshake.c:connection_or_compute_authenticate_cell_body() 231 problem dependency-violation /src/core/or/connection_or.c 20 problem dependency-violation /src/core/or/dos.c 6 problem dependency-violation /src/core/or/onion.c 2 @@ -160,6 +159,7 @@ problem dependency-violation /src/core/or/policies.c 14 problem function-size /src/core/or/protover.c:protover_all_supported() 117 problem dependency-violation /src/core/or/reasons.c 2 problem file-size /src/core/or/relay.c 3264 +problem dependency-violation /src/core/or/relay_handshake.c 5 problem function-size /src/core/or/relay.c:circuit_receive_relay_cell() 127 problem function-size /src/core/or/relay.c:relay_send_command_from_edge_() 109 problem function-size /src/core/or/relay.c:connection_ap_process_end_not_open() 192 diff --git a/src/core/or/channeltls.c b/src/core/or/channeltls.c index 7974da483..71e0c6aa0 100644 --- a/src/core/or/channeltls.c +++ b/src/core/or/channeltls.c @@ -47,6 +47,7 @@ #include "app/config/config.h" #include "core/mainloop/connection.h" #include "core/or/connection_or.h" +#include "core/or/relay_handshake.h" #include "feature/control/control.h" #include "feature/client/entrynodes.h" #include "trunnel/link_handshake.h" diff --git a/src/core/or/connection_or.c b/src/core/or/connection_or.c index 12dca97b7..9302dc864 100644 --- a/src/core/or/connection_or.c +++ b/src/core/or/connection_or.c @@ -39,14 +39,13 @@ #include "app/config/config.h" #include "core/mainloop/connection.h" #include "core/or/connection_or.h" +#include "core/or/relay_handshake.h" #include "feature/control/control_events.h" -#include "lib/crypt_ops/crypto_rand.h" #include "lib/crypt_ops/crypto_util.h" #include "feature/dirauth/reachability.h" #include "feature/client/entrynodes.h" #include "lib/geoip/geoip.h" #include "core/mainloop/mainloop.h" -#include "trunnel/link_handshake.h" #include "trunnel/netinfo.h" #include "feature/nodelist/microdesc.h" #include "feature/nodelist/networkstatus.h" @@ -78,7 +77,6 @@ #include "lib/crypt_ops/crypto_format.h"
#include "lib/tls/tortls.h" -#include "lib/tls/x509.h"
#include "core/or/orconn_event.h"
@@ -2527,533 +2525,3 @@ connection_or_send_netinfo,(or_connection_t *conn))
return r; } - -/** Helper used to add an encoded certs to a cert cell */ -static void -add_certs_cell_cert_helper(certs_cell_t *certs_cell, - uint8_t cert_type, - const uint8_t *cert_encoded, - size_t cert_len) -{ - tor_assert(cert_len <= UINT16_MAX); - certs_cell_cert_t *ccc = certs_cell_cert_new(); - ccc->cert_type = cert_type; - ccc->cert_len = cert_len; - certs_cell_cert_setlen_body(ccc, cert_len); - memcpy(certs_cell_cert_getarray_body(ccc), cert_encoded, cert_len); - - certs_cell_add_certs(certs_cell, ccc); -} - -/** Add an encoded X509 cert (stored as <b>cert_len</b> bytes at - * <b>cert_encoded</b>) to the trunnel certs_cell_t object that we are - * building in <b>certs_cell</b>. Set its type field to <b>cert_type</b>. - * (If <b>cert</b> is NULL, take no action.) */ -static void -add_x509_cert(certs_cell_t *certs_cell, - uint8_t cert_type, - const tor_x509_cert_t *cert) -{ - if (NULL == cert) - return; - - const uint8_t *cert_encoded = NULL; - size_t cert_len; - tor_x509_cert_get_der(cert, &cert_encoded, &cert_len); - - add_certs_cell_cert_helper(certs_cell, cert_type, cert_encoded, cert_len); -} - -/** Add an Ed25519 cert from <b>cert</b> to the trunnel certs_cell_t object - * that we are building in <b>certs_cell</b>. Set its type field to - * <b>cert_type</b>. (If <b>cert</b> is NULL, take no action.) */ -static void -add_ed25519_cert(certs_cell_t *certs_cell, - uint8_t cert_type, - const tor_cert_t *cert) -{ - if (NULL == cert) - return; - - add_certs_cell_cert_helper(certs_cell, cert_type, - cert->encoded, cert->encoded_len); -} - -#ifdef TOR_UNIT_TESTS -int certs_cell_ed25519_disabled_for_testing = 0; -#else -#define certs_cell_ed25519_disabled_for_testing 0 -#endif - -/** Send a CERTS cell on the connection <b>conn</b>. Return 0 on success, -1 - * on failure. */ -int -connection_or_send_certs_cell(or_connection_t *conn) -{ - const tor_x509_cert_t *global_link_cert = NULL, *id_cert = NULL; - tor_x509_cert_t *own_link_cert = NULL; - var_cell_t *cell; - - certs_cell_t *certs_cell = NULL; - - tor_assert(conn->base_.state == OR_CONN_STATE_OR_HANDSHAKING_V3); - - if (! conn->handshake_state) - return -1; - - const int conn_in_server_mode = ! conn->handshake_state->started_here; - - /* Get the encoded values of the X509 certificates */ - if (tor_tls_get_my_certs(conn_in_server_mode, - &global_link_cert, &id_cert) < 0) - return -1; - - if (conn_in_server_mode) { - own_link_cert = tor_tls_get_own_cert(conn->tls); - } - tor_assert(id_cert); - - certs_cell = certs_cell_new(); - - /* Start adding certs. First the link cert or auth1024 cert. */ - if (conn_in_server_mode) { - tor_assert_nonfatal(own_link_cert); - add_x509_cert(certs_cell, - OR_CERT_TYPE_TLS_LINK, own_link_cert); - } else { - tor_assert(global_link_cert); - add_x509_cert(certs_cell, - OR_CERT_TYPE_AUTH_1024, global_link_cert); - } - - /* Next the RSA->RSA ID cert */ - add_x509_cert(certs_cell, - OR_CERT_TYPE_ID_1024, id_cert); - - /* Next the Ed25519 certs */ - add_ed25519_cert(certs_cell, - CERTTYPE_ED_ID_SIGN, - get_master_signing_key_cert()); - if (conn_in_server_mode) { - tor_assert_nonfatal(conn->handshake_state->own_link_cert || - certs_cell_ed25519_disabled_for_testing); - add_ed25519_cert(certs_cell, - CERTTYPE_ED_SIGN_LINK, - conn->handshake_state->own_link_cert); - } else { - add_ed25519_cert(certs_cell, - CERTTYPE_ED_SIGN_AUTH, - get_current_auth_key_cert()); - } - - /* And finally the crosscert. */ - { - const uint8_t *crosscert=NULL; - size_t crosscert_len; - get_master_rsa_crosscert(&crosscert, &crosscert_len); - if (crosscert) { - add_certs_cell_cert_helper(certs_cell, - CERTTYPE_RSA1024_ID_EDID, - crosscert, crosscert_len); - } - } - - /* We've added all the certs; make the cell. */ - certs_cell->n_certs = certs_cell_getlen_certs(certs_cell); - - ssize_t alloc_len = certs_cell_encoded_len(certs_cell); - tor_assert(alloc_len >= 0 && alloc_len <= UINT16_MAX); - cell = var_cell_new(alloc_len); - cell->command = CELL_CERTS; - ssize_t enc_len = certs_cell_encode(cell->payload, alloc_len, certs_cell); - tor_assert(enc_len > 0 && enc_len <= alloc_len); - cell->payload_len = enc_len; - - connection_or_write_var_cell_to_buf(cell, conn); - var_cell_free(cell); - certs_cell_free(certs_cell); - tor_x509_cert_free(own_link_cert); - - return 0; -} - -#ifdef TOR_UNIT_TESTS -int testing__connection_or_pretend_TLSSECRET_is_supported = 0; -#else -#define testing__connection_or_pretend_TLSSECRET_is_supported 0 -#endif - -/** Return true iff <b>challenge_type</b> is an AUTHCHALLENGE type that - * we can send and receive. */ -int -authchallenge_type_is_supported(uint16_t challenge_type) -{ - switch (challenge_type) { - case AUTHTYPE_RSA_SHA256_TLSSECRET: -#ifdef HAVE_WORKING_TOR_TLS_GET_TLSSECRETS - return 1; -#else - return testing__connection_or_pretend_TLSSECRET_is_supported; -#endif - case AUTHTYPE_ED25519_SHA256_RFC5705: - return 1; - case AUTHTYPE_RSA_SHA256_RFC5705: - default: - return 0; - } -} - -/** Return true iff <b>challenge_type_a</b> is one that we would rather - * use than <b>challenge_type_b</b>. */ -int -authchallenge_type_is_better(uint16_t challenge_type_a, - uint16_t challenge_type_b) -{ - /* Any supported type is better than an unsupported one; - * all unsupported types are equally bad. */ - if (!authchallenge_type_is_supported(challenge_type_a)) - return 0; - if (!authchallenge_type_is_supported(challenge_type_b)) - return 1; - /* It happens that types are superior in numerically ascending order. - * If that ever changes, this must change too. */ - return (challenge_type_a > challenge_type_b); -} - -/** Send an AUTH_CHALLENGE cell on the connection <b>conn</b>. Return 0 - * on success, -1 on failure. */ -int -connection_or_send_auth_challenge_cell(or_connection_t *conn) -{ - var_cell_t *cell = NULL; - int r = -1; - tor_assert(conn->base_.state == OR_CONN_STATE_OR_HANDSHAKING_V3); - - if (! conn->handshake_state) - return -1; - - auth_challenge_cell_t *ac = auth_challenge_cell_new(); - - tor_assert(sizeof(ac->challenge) == 32); - crypto_rand((char*)ac->challenge, sizeof(ac->challenge)); - - if (authchallenge_type_is_supported(AUTHTYPE_RSA_SHA256_TLSSECRET)) - auth_challenge_cell_add_methods(ac, AUTHTYPE_RSA_SHA256_TLSSECRET); - /* Disabled, because everything that supports this method also supports - * the much-superior ED25519_SHA256_RFC5705 */ - /* auth_challenge_cell_add_methods(ac, AUTHTYPE_RSA_SHA256_RFC5705); */ - if (authchallenge_type_is_supported(AUTHTYPE_ED25519_SHA256_RFC5705)) - auth_challenge_cell_add_methods(ac, AUTHTYPE_ED25519_SHA256_RFC5705); - auth_challenge_cell_set_n_methods(ac, - auth_challenge_cell_getlen_methods(ac)); - - cell = var_cell_new(auth_challenge_cell_encoded_len(ac)); - ssize_t len = auth_challenge_cell_encode(cell->payload, cell->payload_len, - ac); - if (len != cell->payload_len) { - /* LCOV_EXCL_START */ - log_warn(LD_BUG, "Encoded auth challenge cell length not as expected"); - goto done; - /* LCOV_EXCL_STOP */ - } - cell->command = CELL_AUTH_CHALLENGE; - - connection_or_write_var_cell_to_buf(cell, conn); - r = 0; - - done: - var_cell_free(cell); - auth_challenge_cell_free(ac); - - return r; -} - -/** Compute the main body of an AUTHENTICATE cell that a client can use - * to authenticate itself on a v3 handshake for <b>conn</b>. Return it - * in a var_cell_t. - * - * If <b>server</b> is true, only calculate the first - * V3_AUTH_FIXED_PART_LEN bytes -- the part of the authenticator that's - * determined by the rest of the handshake, and which match the provided value - * exactly. - * - * If <b>server</b> is false and <b>signing_key</b> is NULL, calculate the - * first V3_AUTH_BODY_LEN bytes of the authenticator (that is, everything - * that should be signed), but don't actually sign it. - * - * If <b>server</b> is false and <b>signing_key</b> is provided, calculate the - * entire authenticator, signed with <b>signing_key</b>. - * - * Return the length of the cell body on success, and -1 on failure. - */ -var_cell_t * -connection_or_compute_authenticate_cell_body(or_connection_t *conn, - const int authtype, - crypto_pk_t *signing_key, - const ed25519_keypair_t *ed_signing_key, - int server) -{ - auth1_t *auth = NULL; - auth_ctx_t *ctx = auth_ctx_new(); - var_cell_t *result = NULL; - int old_tlssecrets_algorithm = 0; - const char *authtype_str = NULL; - - int is_ed = 0; - - /* assert state is reasonable XXXX */ - switch (authtype) { - case AUTHTYPE_RSA_SHA256_TLSSECRET: - authtype_str = "AUTH0001"; - old_tlssecrets_algorithm = 1; - break; - case AUTHTYPE_RSA_SHA256_RFC5705: - authtype_str = "AUTH0002"; - break; - case AUTHTYPE_ED25519_SHA256_RFC5705: - authtype_str = "AUTH0003"; - is_ed = 1; - break; - default: - tor_assert(0); - break; - } - - auth = auth1_new(); - ctx->is_ed = is_ed; - - /* Type: 8 bytes. */ - memcpy(auth1_getarray_type(auth), authtype_str, 8); - - { - const tor_x509_cert_t *id_cert=NULL; - const common_digests_t *my_digests, *their_digests; - const uint8_t *my_id, *their_id, *client_id, *server_id; - if (tor_tls_get_my_certs(server, NULL, &id_cert)) - goto err; - my_digests = tor_x509_cert_get_id_digests(id_cert); - their_digests = - tor_x509_cert_get_id_digests(conn->handshake_state->certs->id_cert); - tor_assert(my_digests); - tor_assert(their_digests); - my_id = (uint8_t*)my_digests->d[DIGEST_SHA256]; - their_id = (uint8_t*)their_digests->d[DIGEST_SHA256]; - - client_id = server ? their_id : my_id; - server_id = server ? my_id : their_id; - - /* Client ID digest: 32 octets. */ - memcpy(auth->cid, client_id, 32); - - /* Server ID digest: 32 octets. */ - memcpy(auth->sid, server_id, 32); - } - - if (is_ed) { - const ed25519_public_key_t *my_ed_id, *their_ed_id; - if (!conn->handshake_state->certs->ed_id_sign) { - log_warn(LD_OR, "Ed authenticate without Ed ID cert from peer."); - goto err; - } - my_ed_id = get_master_identity_key(); - their_ed_id = &conn->handshake_state->certs->ed_id_sign->signing_key; - - const uint8_t *cid_ed = (server ? their_ed_id : my_ed_id)->pubkey; - const uint8_t *sid_ed = (server ? my_ed_id : their_ed_id)->pubkey; - - memcpy(auth->u1_cid_ed, cid_ed, ED25519_PUBKEY_LEN); - memcpy(auth->u1_sid_ed, sid_ed, ED25519_PUBKEY_LEN); - } - - { - crypto_digest_t *server_d, *client_d; - if (server) { - server_d = conn->handshake_state->digest_sent; - client_d = conn->handshake_state->digest_received; - } else { - client_d = conn->handshake_state->digest_sent; - server_d = conn->handshake_state->digest_received; - } - - /* Server log digest : 32 octets */ - crypto_digest_get_digest(server_d, (char*)auth->slog, 32); - - /* Client log digest : 32 octets */ - crypto_digest_get_digest(client_d, (char*)auth->clog, 32); - } - - { - /* Digest of cert used on TLS link : 32 octets. */ - tor_x509_cert_t *cert = NULL; - if (server) { - cert = tor_tls_get_own_cert(conn->tls); - } else { - cert = tor_tls_get_peer_cert(conn->tls); - } - if (!cert) { - log_warn(LD_OR, "Unable to find cert when making %s data.", - authtype_str); - goto err; - } - - memcpy(auth->scert, - tor_x509_cert_get_cert_digests(cert)->d[DIGEST_SHA256], 32); - - tor_x509_cert_free(cert); - } - - /* HMAC of clientrandom and serverrandom using master key : 32 octets */ - if (old_tlssecrets_algorithm) { - if (tor_tls_get_tlssecrets(conn->tls, auth->tlssecrets) < 0) { - log_fn(LOG_PROTOCOL_WARN, LD_OR, "Somebody asked us for an older TLS " - "authentication method (AUTHTYPE_RSA_SHA256_TLSSECRET) " - "which we don't support."); - } - } else { - char label[128]; - tor_snprintf(label, sizeof(label), - "EXPORTER FOR TOR TLS CLIENT BINDING %s", authtype_str); - int r = tor_tls_export_key_material(conn->tls, auth->tlssecrets, - auth->cid, sizeof(auth->cid), - label); - if (r < 0) { - if (r != -2) - log_warn(LD_BUG, "TLS key export failed for unknown reason."); - // If r == -2, this was openssl bug 7712. - goto err; - } - } - - /* 8 octets were reserved for the current time, but we're trying to get out - * of the habit of sending time around willynilly. Fortunately, nothing - * checks it. That's followed by 16 bytes of nonce. */ - crypto_rand((char*)auth->rand, 24); - - ssize_t maxlen = auth1_encoded_len(auth, ctx); - if (ed_signing_key && is_ed) { - maxlen += ED25519_SIG_LEN; - } else if (signing_key && !is_ed) { - maxlen += crypto_pk_keysize(signing_key); - } - - const int AUTH_CELL_HEADER_LEN = 4; /* 2 bytes of type, 2 bytes of length */ - result = var_cell_new(AUTH_CELL_HEADER_LEN + maxlen); - uint8_t *const out = result->payload + AUTH_CELL_HEADER_LEN; - const size_t outlen = maxlen; - ssize_t len; - - result->command = CELL_AUTHENTICATE; - set_uint16(result->payload, htons(authtype)); - - if ((len = auth1_encode(out, outlen, auth, ctx)) < 0) { - /* LCOV_EXCL_START */ - log_warn(LD_BUG, "Unable to encode signed part of AUTH1 data."); - goto err; - /* LCOV_EXCL_STOP */ - } - - if (server) { - auth1_t *tmp = NULL; - ssize_t len2 = auth1_parse(&tmp, out, len, ctx); - if (!tmp) { - /* LCOV_EXCL_START */ - log_warn(LD_BUG, "Unable to parse signed part of AUTH1 data that " - "we just encoded"); - goto err; - /* LCOV_EXCL_STOP */ - } - result->payload_len = (tmp->end_of_signed - result->payload); - - auth1_free(tmp); - if (len2 != len) { - /* LCOV_EXCL_START */ - log_warn(LD_BUG, "Mismatched length when re-parsing AUTH1 data."); - goto err; - /* LCOV_EXCL_STOP */ - } - goto done; - } - - if (ed_signing_key && is_ed) { - ed25519_signature_t sig; - if (ed25519_sign(&sig, out, len, ed_signing_key) < 0) { - /* LCOV_EXCL_START */ - log_warn(LD_BUG, "Unable to sign ed25519 authentication data"); - goto err; - /* LCOV_EXCL_STOP */ - } - auth1_setlen_sig(auth, ED25519_SIG_LEN); - memcpy(auth1_getarray_sig(auth), sig.sig, ED25519_SIG_LEN); - - } else if (signing_key && !is_ed) { - auth1_setlen_sig(auth, crypto_pk_keysize(signing_key)); - - char d[32]; - crypto_digest256(d, (char*)out, len, DIGEST_SHA256); - int siglen = crypto_pk_private_sign(signing_key, - (char*)auth1_getarray_sig(auth), - auth1_getlen_sig(auth), - d, 32); - if (siglen < 0) { - log_warn(LD_OR, "Unable to sign AUTH1 data."); - goto err; - } - - auth1_setlen_sig(auth, siglen); - } - - len = auth1_encode(out, outlen, auth, ctx); - if (len < 0) { - /* LCOV_EXCL_START */ - log_warn(LD_BUG, "Unable to encode signed AUTH1 data."); - goto err; - /* LCOV_EXCL_STOP */ - } - tor_assert(len + AUTH_CELL_HEADER_LEN <= result->payload_len); - result->payload_len = len + AUTH_CELL_HEADER_LEN; - set_uint16(result->payload+2, htons(len)); - - goto done; - - err: - var_cell_free(result); - result = NULL; - done: - auth1_free(auth); - auth_ctx_free(ctx); - return result; -} - -/** Send an AUTHENTICATE cell on the connection <b>conn</b>. Return 0 on - * success, -1 on failure */ -MOCK_IMPL(int, -connection_or_send_authenticate_cell,(or_connection_t *conn, int authtype)) -{ - var_cell_t *cell; - crypto_pk_t *pk = tor_tls_get_my_client_auth_key(); - /* XXXX make sure we're actually supposed to send this! */ - - if (!pk) { - log_warn(LD_BUG, "Can't compute authenticate cell: no client auth key"); - return -1; - } - if (! authchallenge_type_is_supported(authtype)) { - log_warn(LD_BUG, "Tried to send authenticate cell with unknown " - "authentication type %d", authtype); - return -1; - } - - cell = connection_or_compute_authenticate_cell_body(conn, - authtype, - pk, - get_current_auth_keypair(), - 0 /* not server */); - if (! cell) { - log_fn(LOG_PROTOCOL_WARN, LD_NET, "Unable to compute authenticate cell!"); - return -1; - } - connection_or_write_var_cell_to_buf(cell, conn); - var_cell_free(cell); - - return 0; -} diff --git a/src/core/or/connection_or.h b/src/core/or/connection_or.h index 90b21ad77..02bc87a86 100644 --- a/src/core/or/connection_or.h +++ b/src/core/or/connection_or.h @@ -97,19 +97,6 @@ MOCK_DECL(void,connection_or_write_var_cell_to_buf,(const var_cell_t *cell, or_connection_t *conn)); int connection_or_send_versions(or_connection_t *conn, int v3_plus); MOCK_DECL(int,connection_or_send_netinfo,(or_connection_t *conn)); -int connection_or_send_certs_cell(or_connection_t *conn); -int connection_or_send_auth_challenge_cell(or_connection_t *conn); -int authchallenge_type_is_supported(uint16_t challenge_type); -int authchallenge_type_is_better(uint16_t challenge_type_a, - uint16_t challenge_type_b); -var_cell_t *connection_or_compute_authenticate_cell_body( - or_connection_t *conn, - const int authtype, - crypto_pk_t *signing_key, - const struct ed25519_keypair_t *ed_signing_key, - int server); -MOCK_DECL(int,connection_or_send_authenticate_cell, - (or_connection_t *conn, int type));
int is_or_protocol_version_known(uint16_t version);
@@ -144,7 +131,6 @@ MOCK_DECL(STATIC void,connection_or_change_state, #endif /* defined(CONNECTION_OR_PRIVATE) */
#ifdef TOR_UNIT_TESTS -extern int certs_cell_ed25519_disabled_for_testing; extern int testing__connection_or_pretend_TLSSECRET_is_supported; #endif
diff --git a/src/core/or/include.am b/src/core/or/include.am index 4dd251d2e..8f0f0bb61 100644 --- a/src/core/or/include.am +++ b/src/core/or/include.am @@ -3,6 +3,7 @@ LIBTOR_APP_A_SOURCES += \ src/core/or/address_set.c \ src/core/or/channel.c \ + src/core/or/relay_handshake.c \ src/core/or/channelpadding.c \ src/core/or/channeltls.c \ src/core/or/circuitbuild.c \ @@ -42,6 +43,7 @@ noinst_HEADERS += \ src/core/or/cell_queue_st.h \ src/core/or/cell_st.h \ src/core/or/channel.h \ + src/core/or/relay_handshake.h \ src/core/or/channelpadding.h \ src/core/or/channeltls.h \ src/core/or/circuit_st.h \ diff --git a/src/core/or/relay_handshake.c b/src/core/or/relay_handshake.c new file mode 100644 index 000000000..78b7da737 --- /dev/null +++ b/src/core/or/relay_handshake.c @@ -0,0 +1,565 @@ +/* Copyright (c) 2001 Matej Pfajfar. + * Copyright (c) 2001-2004, Roger Dingledine. + * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson. + * Copyright (c) 2007-2020, The Tor Project, Inc. */ +/* See LICENSE for licensing information */ + +/** + * @file relay_handshake.c + * @brief Functions to implement the relay-only parts of our + * connection handshake. + * + * Some parts of our TLS link handshake are only done by relays (including + * bridges). Specifically, only relays need to send CERTS cells; only + * relays need to send or receive AUTHCHALLENGE cells, and only relays need to + * send or receive AUTHENTICATE cells. + **/ + +#include "orconfig.h" +#include "core/or/or.h" +#include "core/or/relay_handshake.h" + +#include "app/config/config.h" +#include "core/or/connection_or.h" +#include "lib/crypt_ops/crypto_rand.h" +#include "trunnel/link_handshake.h" +#include "feature/relay/routerkeys.h" +#include "feature/nodelist/torcert.h" + +#include "core/or/or_connection_st.h" +#include "core/or/or_handshake_certs_st.h" +#include "core/or/or_handshake_state_st.h" +#include "core/or/var_cell_st.h" + +#include "lib/tls/tortls.h" +#include "lib/tls/x509.h" + +/** Helper used to add an encoded certs to a cert cell */ +static void +add_certs_cell_cert_helper(certs_cell_t *certs_cell, + uint8_t cert_type, + const uint8_t *cert_encoded, + size_t cert_len) +{ + tor_assert(cert_len <= UINT16_MAX); + certs_cell_cert_t *ccc = certs_cell_cert_new(); + ccc->cert_type = cert_type; + ccc->cert_len = cert_len; + certs_cell_cert_setlen_body(ccc, cert_len); + memcpy(certs_cell_cert_getarray_body(ccc), cert_encoded, cert_len); + + certs_cell_add_certs(certs_cell, ccc); +} + +/** Add an encoded X509 cert (stored as <b>cert_len</b> bytes at + * <b>cert_encoded</b>) to the trunnel certs_cell_t object that we are + * building in <b>certs_cell</b>. Set its type field to <b>cert_type</b>. + * (If <b>cert</b> is NULL, take no action.) */ +static void +add_x509_cert(certs_cell_t *certs_cell, + uint8_t cert_type, + const tor_x509_cert_t *cert) +{ + if (NULL == cert) + return; + + const uint8_t *cert_encoded = NULL; + size_t cert_len; + tor_x509_cert_get_der(cert, &cert_encoded, &cert_len); + + add_certs_cell_cert_helper(certs_cell, cert_type, cert_encoded, cert_len); +} + +/** Add an Ed25519 cert from <b>cert</b> to the trunnel certs_cell_t object + * that we are building in <b>certs_cell</b>. Set its type field to + * <b>cert_type</b>. (If <b>cert</b> is NULL, take no action.) */ +static void +add_ed25519_cert(certs_cell_t *certs_cell, + uint8_t cert_type, + const tor_cert_t *cert) +{ + if (NULL == cert) + return; + + add_certs_cell_cert_helper(certs_cell, cert_type, + cert->encoded, cert->encoded_len); +} + +#ifdef TOR_UNIT_TESTS +int certs_cell_ed25519_disabled_for_testing = 0; +#else +#define certs_cell_ed25519_disabled_for_testing 0 +#endif + +/** Send a CERTS cell on the connection <b>conn</b>. Return 0 on success, -1 + * on failure. */ +int +connection_or_send_certs_cell(or_connection_t *conn) +{ + const tor_x509_cert_t *global_link_cert = NULL, *id_cert = NULL; + tor_x509_cert_t *own_link_cert = NULL; + var_cell_t *cell; + + certs_cell_t *certs_cell = NULL; + + tor_assert(conn->base_.state == OR_CONN_STATE_OR_HANDSHAKING_V3); + + if (! conn->handshake_state) + return -1; + + const int conn_in_server_mode = ! conn->handshake_state->started_here; + + /* Get the encoded values of the X509 certificates */ + if (tor_tls_get_my_certs(conn_in_server_mode, + &global_link_cert, &id_cert) < 0) + return -1; + + if (conn_in_server_mode) { + own_link_cert = tor_tls_get_own_cert(conn->tls); + } + tor_assert(id_cert); + + certs_cell = certs_cell_new(); + + /* Start adding certs. First the link cert or auth1024 cert. */ + if (conn_in_server_mode) { + tor_assert_nonfatal(own_link_cert); + add_x509_cert(certs_cell, + OR_CERT_TYPE_TLS_LINK, own_link_cert); + } else { + tor_assert(global_link_cert); + add_x509_cert(certs_cell, + OR_CERT_TYPE_AUTH_1024, global_link_cert); + } + + /* Next the RSA->RSA ID cert */ + add_x509_cert(certs_cell, + OR_CERT_TYPE_ID_1024, id_cert); + + /* Next the Ed25519 certs */ + add_ed25519_cert(certs_cell, + CERTTYPE_ED_ID_SIGN, + get_master_signing_key_cert()); + if (conn_in_server_mode) { + tor_assert_nonfatal(conn->handshake_state->own_link_cert || + certs_cell_ed25519_disabled_for_testing); + add_ed25519_cert(certs_cell, + CERTTYPE_ED_SIGN_LINK, + conn->handshake_state->own_link_cert); + } else { + add_ed25519_cert(certs_cell, + CERTTYPE_ED_SIGN_AUTH, + get_current_auth_key_cert()); + } + + /* And finally the crosscert. */ + { + const uint8_t *crosscert=NULL; + size_t crosscert_len; + get_master_rsa_crosscert(&crosscert, &crosscert_len); + if (crosscert) { + add_certs_cell_cert_helper(certs_cell, + CERTTYPE_RSA1024_ID_EDID, + crosscert, crosscert_len); + } + } + + /* We've added all the certs; make the cell. */ + certs_cell->n_certs = certs_cell_getlen_certs(certs_cell); + + ssize_t alloc_len = certs_cell_encoded_len(certs_cell); + tor_assert(alloc_len >= 0 && alloc_len <= UINT16_MAX); + cell = var_cell_new(alloc_len); + cell->command = CELL_CERTS; + ssize_t enc_len = certs_cell_encode(cell->payload, alloc_len, certs_cell); + tor_assert(enc_len > 0 && enc_len <= alloc_len); + cell->payload_len = enc_len; + + connection_or_write_var_cell_to_buf(cell, conn); + var_cell_free(cell); + certs_cell_free(certs_cell); + tor_x509_cert_free(own_link_cert); + + return 0; +} + +#ifdef TOR_UNIT_TESTS +int testing__connection_or_pretend_TLSSECRET_is_supported = 0; +#else +#define testing__connection_or_pretend_TLSSECRET_is_supported 0 +#endif + +/** Return true iff <b>challenge_type</b> is an AUTHCHALLENGE type that + * we can send and receive. */ +int +authchallenge_type_is_supported(uint16_t challenge_type) +{ + switch (challenge_type) { + case AUTHTYPE_RSA_SHA256_TLSSECRET: +#ifdef HAVE_WORKING_TOR_TLS_GET_TLSSECRETS + return 1; +#else + return testing__connection_or_pretend_TLSSECRET_is_supported; +#endif + case AUTHTYPE_ED25519_SHA256_RFC5705: + return 1; + case AUTHTYPE_RSA_SHA256_RFC5705: + default: + return 0; + } +} + +/** Return true iff <b>challenge_type_a</b> is one that we would rather + * use than <b>challenge_type_b</b>. */ +int +authchallenge_type_is_better(uint16_t challenge_type_a, + uint16_t challenge_type_b) +{ + /* Any supported type is better than an unsupported one; + * all unsupported types are equally bad. */ + if (!authchallenge_type_is_supported(challenge_type_a)) + return 0; + if (!authchallenge_type_is_supported(challenge_type_b)) + return 1; + /* It happens that types are superior in numerically ascending order. + * If that ever changes, this must change too. */ + return (challenge_type_a > challenge_type_b); +} + +/** Send an AUTH_CHALLENGE cell on the connection <b>conn</b>. Return 0 + * on success, -1 on failure. */ +int +connection_or_send_auth_challenge_cell(or_connection_t *conn) +{ + var_cell_t *cell = NULL; + int r = -1; + tor_assert(conn->base_.state == OR_CONN_STATE_OR_HANDSHAKING_V3); + + if (! conn->handshake_state) + return -1; + + auth_challenge_cell_t *ac = auth_challenge_cell_new(); + + tor_assert(sizeof(ac->challenge) == 32); + crypto_rand((char*)ac->challenge, sizeof(ac->challenge)); + + if (authchallenge_type_is_supported(AUTHTYPE_RSA_SHA256_TLSSECRET)) + auth_challenge_cell_add_methods(ac, AUTHTYPE_RSA_SHA256_TLSSECRET); + /* Disabled, because everything that supports this method also supports + * the much-superior ED25519_SHA256_RFC5705 */ + /* auth_challenge_cell_add_methods(ac, AUTHTYPE_RSA_SHA256_RFC5705); */ + if (authchallenge_type_is_supported(AUTHTYPE_ED25519_SHA256_RFC5705)) + auth_challenge_cell_add_methods(ac, AUTHTYPE_ED25519_SHA256_RFC5705); + auth_challenge_cell_set_n_methods(ac, + auth_challenge_cell_getlen_methods(ac)); + + cell = var_cell_new(auth_challenge_cell_encoded_len(ac)); + ssize_t len = auth_challenge_cell_encode(cell->payload, cell->payload_len, + ac); + if (len != cell->payload_len) { + /* LCOV_EXCL_START */ + log_warn(LD_BUG, "Encoded auth challenge cell length not as expected"); + goto done; + /* LCOV_EXCL_STOP */ + } + cell->command = CELL_AUTH_CHALLENGE; + + connection_or_write_var_cell_to_buf(cell, conn); + r = 0; + + done: + var_cell_free(cell); + auth_challenge_cell_free(ac); + + return r; +} + +/** Compute the main body of an AUTHENTICATE cell that a client can use + * to authenticate itself on a v3 handshake for <b>conn</b>. Return it + * in a var_cell_t. + * + * If <b>server</b> is true, only calculate the first + * V3_AUTH_FIXED_PART_LEN bytes -- the part of the authenticator that's + * determined by the rest of the handshake, and which match the provided value + * exactly. + * + * If <b>server</b> is false and <b>signing_key</b> is NULL, calculate the + * first V3_AUTH_BODY_LEN bytes of the authenticator (that is, everything + * that should be signed), but don't actually sign it. + * + * If <b>server</b> is false and <b>signing_key</b> is provided, calculate the + * entire authenticator, signed with <b>signing_key</b>. + * + * Return the length of the cell body on success, and -1 on failure. + */ +var_cell_t * +connection_or_compute_authenticate_cell_body(or_connection_t *conn, + const int authtype, + crypto_pk_t *signing_key, + const ed25519_keypair_t *ed_signing_key, + int server) +{ + auth1_t *auth = NULL; + auth_ctx_t *ctx = auth_ctx_new(); + var_cell_t *result = NULL; + int old_tlssecrets_algorithm = 0; + const char *authtype_str = NULL; + + int is_ed = 0; + + /* assert state is reasonable XXXX */ + switch (authtype) { + case AUTHTYPE_RSA_SHA256_TLSSECRET: + authtype_str = "AUTH0001"; + old_tlssecrets_algorithm = 1; + break; + case AUTHTYPE_RSA_SHA256_RFC5705: + authtype_str = "AUTH0002"; + break; + case AUTHTYPE_ED25519_SHA256_RFC5705: + authtype_str = "AUTH0003"; + is_ed = 1; + break; + default: + tor_assert(0); + break; + } + + auth = auth1_new(); + ctx->is_ed = is_ed; + + /* Type: 8 bytes. */ + memcpy(auth1_getarray_type(auth), authtype_str, 8); + + { + const tor_x509_cert_t *id_cert=NULL; + const common_digests_t *my_digests, *their_digests; + const uint8_t *my_id, *their_id, *client_id, *server_id; + if (tor_tls_get_my_certs(server, NULL, &id_cert)) + goto err; + my_digests = tor_x509_cert_get_id_digests(id_cert); + their_digests = + tor_x509_cert_get_id_digests(conn->handshake_state->certs->id_cert); + tor_assert(my_digests); + tor_assert(their_digests); + my_id = (uint8_t*)my_digests->d[DIGEST_SHA256]; + their_id = (uint8_t*)their_digests->d[DIGEST_SHA256]; + + client_id = server ? their_id : my_id; + server_id = server ? my_id : their_id; + + /* Client ID digest: 32 octets. */ + memcpy(auth->cid, client_id, 32); + + /* Server ID digest: 32 octets. */ + memcpy(auth->sid, server_id, 32); + } + + if (is_ed) { + const ed25519_public_key_t *my_ed_id, *their_ed_id; + if (!conn->handshake_state->certs->ed_id_sign) { + log_warn(LD_OR, "Ed authenticate without Ed ID cert from peer."); + goto err; + } + my_ed_id = get_master_identity_key(); + their_ed_id = &conn->handshake_state->certs->ed_id_sign->signing_key; + + const uint8_t *cid_ed = (server ? their_ed_id : my_ed_id)->pubkey; + const uint8_t *sid_ed = (server ? my_ed_id : their_ed_id)->pubkey; + + memcpy(auth->u1_cid_ed, cid_ed, ED25519_PUBKEY_LEN); + memcpy(auth->u1_sid_ed, sid_ed, ED25519_PUBKEY_LEN); + } + + { + crypto_digest_t *server_d, *client_d; + if (server) { + server_d = conn->handshake_state->digest_sent; + client_d = conn->handshake_state->digest_received; + } else { + client_d = conn->handshake_state->digest_sent; + server_d = conn->handshake_state->digest_received; + } + + /* Server log digest : 32 octets */ + crypto_digest_get_digest(server_d, (char*)auth->slog, 32); + + /* Client log digest : 32 octets */ + crypto_digest_get_digest(client_d, (char*)auth->clog, 32); + } + + { + /* Digest of cert used on TLS link : 32 octets. */ + tor_x509_cert_t *cert = NULL; + if (server) { + cert = tor_tls_get_own_cert(conn->tls); + } else { + cert = tor_tls_get_peer_cert(conn->tls); + } + if (!cert) { + log_warn(LD_OR, "Unable to find cert when making %s data.", + authtype_str); + goto err; + } + + memcpy(auth->scert, + tor_x509_cert_get_cert_digests(cert)->d[DIGEST_SHA256], 32); + + tor_x509_cert_free(cert); + } + + /* HMAC of clientrandom and serverrandom using master key : 32 octets */ + if (old_tlssecrets_algorithm) { + if (tor_tls_get_tlssecrets(conn->tls, auth->tlssecrets) < 0) { + log_fn(LOG_PROTOCOL_WARN, LD_OR, "Somebody asked us for an older TLS " + "authentication method (AUTHTYPE_RSA_SHA256_TLSSECRET) " + "which we don't support."); + } + } else { + char label[128]; + tor_snprintf(label, sizeof(label), + "EXPORTER FOR TOR TLS CLIENT BINDING %s", authtype_str); + int r = tor_tls_export_key_material(conn->tls, auth->tlssecrets, + auth->cid, sizeof(auth->cid), + label); + if (r < 0) { + if (r != -2) + log_warn(LD_BUG, "TLS key export failed for unknown reason."); + // If r == -2, this was openssl bug 7712. + goto err; + } + } + + /* 8 octets were reserved for the current time, but we're trying to get out + * of the habit of sending time around willynilly. Fortunately, nothing + * checks it. That's followed by 16 bytes of nonce. */ + crypto_rand((char*)auth->rand, 24); + + ssize_t maxlen = auth1_encoded_len(auth, ctx); + if (ed_signing_key && is_ed) { + maxlen += ED25519_SIG_LEN; + } else if (signing_key && !is_ed) { + maxlen += crypto_pk_keysize(signing_key); + } + + const int AUTH_CELL_HEADER_LEN = 4; /* 2 bytes of type, 2 bytes of length */ + result = var_cell_new(AUTH_CELL_HEADER_LEN + maxlen); + uint8_t *const out = result->payload + AUTH_CELL_HEADER_LEN; + const size_t outlen = maxlen; + ssize_t len; + + result->command = CELL_AUTHENTICATE; + set_uint16(result->payload, htons(authtype)); + + if ((len = auth1_encode(out, outlen, auth, ctx)) < 0) { + /* LCOV_EXCL_START */ + log_warn(LD_BUG, "Unable to encode signed part of AUTH1 data."); + goto err; + /* LCOV_EXCL_STOP */ + } + + if (server) { + auth1_t *tmp = NULL; + ssize_t len2 = auth1_parse(&tmp, out, len, ctx); + if (!tmp) { + /* LCOV_EXCL_START */ + log_warn(LD_BUG, "Unable to parse signed part of AUTH1 data that " + "we just encoded"); + goto err; + /* LCOV_EXCL_STOP */ + } + result->payload_len = (tmp->end_of_signed - result->payload); + + auth1_free(tmp); + if (len2 != len) { + /* LCOV_EXCL_START */ + log_warn(LD_BUG, "Mismatched length when re-parsing AUTH1 data."); + goto err; + /* LCOV_EXCL_STOP */ + } + goto done; + } + + if (ed_signing_key && is_ed) { + ed25519_signature_t sig; + if (ed25519_sign(&sig, out, len, ed_signing_key) < 0) { + /* LCOV_EXCL_START */ + log_warn(LD_BUG, "Unable to sign ed25519 authentication data"); + goto err; + /* LCOV_EXCL_STOP */ + } + auth1_setlen_sig(auth, ED25519_SIG_LEN); + memcpy(auth1_getarray_sig(auth), sig.sig, ED25519_SIG_LEN); + + } else if (signing_key && !is_ed) { + auth1_setlen_sig(auth, crypto_pk_keysize(signing_key)); + + char d[32]; + crypto_digest256(d, (char*)out, len, DIGEST_SHA256); + int siglen = crypto_pk_private_sign(signing_key, + (char*)auth1_getarray_sig(auth), + auth1_getlen_sig(auth), + d, 32); + if (siglen < 0) { + log_warn(LD_OR, "Unable to sign AUTH1 data."); + goto err; + } + + auth1_setlen_sig(auth, siglen); + } + + len = auth1_encode(out, outlen, auth, ctx); + if (len < 0) { + /* LCOV_EXCL_START */ + log_warn(LD_BUG, "Unable to encode signed AUTH1 data."); + goto err; + /* LCOV_EXCL_STOP */ + } + tor_assert(len + AUTH_CELL_HEADER_LEN <= result->payload_len); + result->payload_len = len + AUTH_CELL_HEADER_LEN; + set_uint16(result->payload+2, htons(len)); + + goto done; + + err: + var_cell_free(result); + result = NULL; + done: + auth1_free(auth); + auth_ctx_free(ctx); + return result; +} + +/** Send an AUTHENTICATE cell on the connection <b>conn</b>. Return 0 on + * success, -1 on failure */ +MOCK_IMPL(int, +connection_or_send_authenticate_cell,(or_connection_t *conn, int authtype)) +{ + var_cell_t *cell; + crypto_pk_t *pk = tor_tls_get_my_client_auth_key(); + /* XXXX make sure we're actually supposed to send this! */ + + if (!pk) { + log_warn(LD_BUG, "Can't compute authenticate cell: no client auth key"); + return -1; + } + if (! authchallenge_type_is_supported(authtype)) { + log_warn(LD_BUG, "Tried to send authenticate cell with unknown " + "authentication type %d", authtype); + return -1; + } + + cell = connection_or_compute_authenticate_cell_body(conn, + authtype, + pk, + get_current_auth_keypair(), + 0 /* not server */); + if (! cell) { + log_fn(LOG_PROTOCOL_WARN, LD_NET, "Unable to compute authenticate cell!"); + return -1; + } + connection_or_write_var_cell_to_buf(cell, conn); + var_cell_free(cell); + + return 0; +} diff --git a/src/core/or/relay_handshake.h b/src/core/or/relay_handshake.h new file mode 100644 index 000000000..987038cc7 --- /dev/null +++ b/src/core/or/relay_handshake.h @@ -0,0 +1,38 @@ +/* Copyright (c) 2001 Matej Pfajfar. + * Copyright (c) 2001-2004, Roger Dingledine. + * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson. + * Copyright (c) 2007-2020, The Tor Project, Inc. */ +/* See LICENSE for licensing information */ + +/** + * @file relay_handshake.h + * @brief Header for core/or/relay_handshake.c + **/ + +#ifndef TOR_CORE_OR_RELAY_HANDSHAKE_H +#define TOR_CORE_OR_RELAY_HANDSHAKE_H + +struct ed25519_keypair_t; + +int connection_or_send_certs_cell(or_connection_t *conn); +int connection_or_send_auth_challenge_cell(or_connection_t *conn); + +var_cell_t *connection_or_compute_authenticate_cell_body( + or_connection_t *conn, + const int authtype, + crypto_pk_t *signing_key, + const struct ed25519_keypair_t *ed_signing_key, + int server); + +int authchallenge_type_is_supported(uint16_t challenge_type); +int authchallenge_type_is_better(uint16_t challenge_type_a, + uint16_t challenge_type_b); + +MOCK_DECL(int,connection_or_send_authenticate_cell, + (or_connection_t *conn, int type)); + +#ifdef TOR_UNIT_TESTS +extern int certs_cell_ed25519_disabled_for_testing; +#endif + +#endif /* !defined(TOR_CORE_OR_RELAY_HANDSHAKE_H) */ diff --git a/src/test/test_link_handshake.c b/src/test/test_link_handshake.c index 96542ce7a..98e8447d8 100644 --- a/src/test/test_link_handshake.c +++ b/src/test/test_link_handshake.c @@ -18,6 +18,7 @@ #include "feature/relay/routerkeys.h" #include "core/or/scheduler.h" #include "feature/nodelist/torcert.h" +#include "core/or/relay_handshake.h"
#include "core/or/or_connection_st.h" #include "core/or/or_handshake_certs_st.h"