October 2011 - tor-commits - lists.torproject.org

[tor/master] Basic function to write authenticate cells
by nickm＠torproject.org 11 Oct '11

11 Oct '11

commit 81024f43ec3a3ab32683764cb925606bfcb603d7 Author: Nick Mathewson <nickm(a)torproject.org> Date: Wed Sep 14 14:44:42 2011 -0400 Basic function to write authenticate cells Also, tweak the cert cell code to send auth certs --- src/or/connection_or.c | 195 +++++++++++++++++++++++++++++++++++++++++++++++- src/or/connection_or.h | 5 + 2 files changed, 197 insertions(+), 3 deletions(-) diff --git a/src/or/connection_or.c b/src/or/connection_or.c index dcb838b..c72d89d 100644 --- a/src/or/connection_or.c +++ b/src/or/connection_or.c @@ -1776,13 +1776,14 @@ connection_or_send_cert_cell(or_connection_t *conn) var_cell_t *cell; size_t cell_len; int pos; + int server_mode; tor_assert(conn->_base.state == OR_CONN_STATE_OR_HANDSHAKING_V3); if (! conn->handshake_state) return -1; - if (tor_tls_get_my_certs(! conn->handshake_state->started_here, - &link_cert, &id_cert) < 0) + server_mode = ! conn->handshake_state->started_here; + if (tor_tls_get_my_certs(server_mode, &link_cert, &id_cert) < 0) return -1; tor_cert_get_der(link_cert, &link_encoded, &link_len); tor_cert_get_der(id_cert, &id_encoded, &id_len); @@ -1795,7 +1796,10 @@ connection_or_send_cert_cell(or_connection_t *conn) cell->payload[0] = 2; pos = 1; - cell->payload[pos] = OR_CERT_TYPE_TLS_LINK; /* Link cert */ + if (server_mode) + cell->payload[pos] = OR_CERT_TYPE_TLS_LINK; /* Link cert */ + else + cell->payload[pos] = OR_CERT_TYPE_AUTH_1024; /* client authentication */ set_uint16(&cell->payload[pos+1], htons(link_len)); memcpy(&cell->payload[pos+3], link_encoded, link_len); pos += 3 + link_len; @@ -1842,3 +1846,188 @@ connection_or_send_auth_challenge_cell(or_connection_t *conn) return 0; } +/** DOCDOC */ +#define V3_HS_AUTH_FIXED_PART_LEN (8+(32*6)) +#define V3_HS_AUTH_BODY_LEN (V3_HS_AUTH_FIXED_PART_LEN + 8 + 16) + +#define AUTHTYPE_RSA_SHA256_TLSSECRET 1 + +/** Compute the main body of an AUTHENTICATE cell that a client can use + * to authenticate itself on a v3 handshake for conn. Write it to the + * outlen-byte buffer at out. + * + * If server is true, only calculate the first + * V3_HS_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 server is false and signing_key is NULL, calculate the + * first V3_HS_AUTH_BODY_LEN bytes of the authenticator (that is, everything + * that should be signed), but don't actually sign it. + * + * If server is false and signing_key is provided, calculate the + * entire authenticator, signed with signing_key. + */ +int +connection_or_compute_authenticate_cell_body(or_connection_t *conn, + uint8_t *out, size_t outlen, + crypto_pk_env_t *signing_key, + int server) +{ + uint8_t *ptr; + + /* assert state is reasonable XXXX */ + + if (outlen < V3_HS_AUTH_FIXED_PART_LEN || + (!server && outlen < V3_HS_AUTH_BODY_LEN)) + return -1; + + ptr = out; + + /* Type: 8 bytes. */ + memcpy(ptr, "AUTH0001", 8); + ptr += 8; + + { + const tor_cert_t *id_cert=NULL, *link_cert=NULL; + const uint8_t *my_id, *their_id, *client_id, *server_id; + if (tor_tls_get_my_certs(0, &link_cert, &id_cert)) + return -1; + my_id = (uint8_t*)tor_cert_get_id_digests(id_cert)->d[DIGEST_SHA256]; + their_id = (uint8_t*) + tor_cert_get_id_digests(conn->handshake_state->id_cert)->d[DIGEST_SHA256]; + client_id = server ? their_id : my_id; + server_id = server ? my_id : their_id; + + /* Client ID digest: 32 octets. */ + memcpy(ptr, client_id, 32); + ptr += 32; + + /* Server ID digest: 32 octets. */ + memcpy(ptr, server_id, 32); + ptr += 32; + } + + { + crypto_digest_env_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*)ptr, 32); + ptr += 32; + + /* Client log digest : 32 octets */ + crypto_digest_get_digest(client_d, (char*)ptr, 32); + ptr += 32; + } + + { + /* Digest of cert used on TLS link : 32 octets. */ + const tor_cert_t *cert = NULL; + tor_cert_t *freecert = NULL; + if (server) { + tor_tls_get_my_certs(1, &cert, NULL); + } else { + freecert = tor_tls_get_peer_cert(conn->tls); + cert = freecert; + } + if (!cert) + return -1; + memcpy(ptr, tor_cert_get_cert_digests(cert)->d[DIGEST_SHA256], 32); + + if (freecert) + tor_cert_free(freecert); + ptr += 32; + } + + /* HMAC of clientrandom and serverrandom using master key : 32 octets */ + tor_tls_get_tlssecrets(conn->tls, ptr); + ptr += 32; + + tor_assert(ptr - out == V3_HS_AUTH_FIXED_PART_LEN); + + if (server) + return ptr-out; + + /* Time: 8 octets. */ + { + uint64_t now = time(NULL); + if ((time_t)now < 0) + return -1; + set_uint32(ptr, htonl((uint32_t)(now>>32))); + set_uint32(ptr+4, htonl((uint32_t)now)); + ptr += 8; + } + + /* Nonce: 16 octets. */ + crypto_rand((char*)ptr, 16); + ptr += 16; + + tor_assert(ptr - out == V3_HS_AUTH_BODY_LEN); + + if (!signing_key) + return ptr - out; + + { + int siglen; + char d[32]; + crypto_digest256(d, (char*)out, ptr-out, DIGEST_SHA256); + siglen = crypto_pk_private_sign(signing_key, + (char*)ptr, outlen - (ptr-out), + d, 32); + if (siglen < 0) + return -1; + + ptr += siglen; + tor_assert(ptr <= out+outlen); + return ptr - out; + } +} + +/** Send an AUTHENTICATE cell on the connection conn. Return 0 on + * success, -1 on failure */ +int +connection_or_send_authenticate_cell(or_connection_t *conn) +{ + var_cell_t *cell; + crypto_pk_env_t *pk = tor_tls_get_my_client_auth_key(); + int authlen; + int cell_maxlen; + /* XXXX make sure we're actually supposed to send this! */ + + if (!pk) + return -1;/*XXXX log*/ + cell_maxlen = 4 + /* overhead */ + V3_HS_AUTH_BODY_LEN + /* Authentication body */ + crypto_pk_keysize(pk) + /* Max signature length */ + 16 /* just in case XXXX */ ; + + cell = var_cell_new(cell_maxlen); + set_uint16(cell->payload, htons(AUTHTYPE_RSA_SHA256_TLSSECRET)); + /* skip over length ; we don't know that yet. */ + + authlen = connection_or_compute_authenticate_cell_body(conn, + cell->payload+4, + cell_maxlen-4, + pk, + 0 /* not server */); + if (authlen < 0) { + /* XXXX log */ + var_cell_free(cell); + return -1; + } + tor_assert(authlen + 4 <= cell->payload_len); + set_uint16(cell->payload+2, htons(authlen)); + cell->payload_len = authlen + 4; + + connection_or_write_var_cell_to_buf(cell, conn); + var_cell_free(cell); + + return 0; +} diff --git a/src/or/connection_or.h b/src/or/connection_or.h index 6e50e29..ba441c4 100644 --- a/src/or/connection_or.h +++ b/src/or/connection_or.h @@ -52,6 +52,11 @@ int connection_or_send_destroy(circid_t circ_id, or_connection_t *conn, int connection_or_send_netinfo(or_connection_t *conn); int connection_or_send_cert_cell(or_connection_t *conn); int connection_or_send_auth_challenge_cell(or_connection_t *conn); +int connection_or_compute_authenticate_cell_body(or_connection_t *conn, + uint8_t *out, size_t outlen, + crypto_pk_env_t *signing_key, + int server); +int connection_or_send_authenticate_cell(or_connection_t *conn); int is_or_protocol_version_known(uint16_t version);

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[tor/master] Function to return peer cert as tor_tls_cert
by nickm＠torproject.org 11 Oct '11

11 Oct '11

commit e48e47fa03fa09d89527c1bbfaee4c9d7d3eee6e Author: Nick Mathewson <nickm(a)torproject.org> Date: Thu Sep 22 11:01:14 2011 -0400 Function to return peer cert as tor_tls_cert --- src/common/tortls.c | 12 ++++++++++++ src/common/tortls.h | 1 + 2 files changed, 13 insertions(+), 0 deletions(-) diff --git a/src/common/tortls.c b/src/common/tortls.c index e275307..aa90f18 100644 --- a/src/common/tortls.c +++ b/src/common/tortls.c @@ -1856,6 +1856,18 @@ tor_tls_peer_has_cert(tor_tls_t *tls) return 1; } +/** Return the peer certificate, or NULL if there isn't one. */ +tor_cert_t * +tor_tls_get_peer_cert(tor_tls_t *tls) +{ + X509 *cert; + cert = SSL_get_peer_certificate(tls->ssl); + tls_log_errors(tls, LOG_WARN, LD_HANDSHAKE, "getting peer certificate"); + if (!cert) + return NULL; + return tor_cert_new(cert); +} + /** Warn that a certificate lifetime extends through a certain range. */ static void log_cert_lifetime(const X509 *cert, const char *problem) diff --git a/src/common/tortls.h b/src/common/tortls.h index b522dd1..00bf406 100644 --- a/src/common/tortls.h +++ b/src/common/tortls.h @@ -66,6 +66,7 @@ void tor_tls_set_renegotiate_callback(tor_tls_t *tls, int tor_tls_is_server(tor_tls_t *tls); void tor_tls_free(tor_tls_t *tls); int tor_tls_peer_has_cert(tor_tls_t *tls); +tor_cert_t *tor_tls_get_peer_cert(tor_tls_t *tls); int tor_tls_verify(int severity, tor_tls_t *tls, crypto_pk_env_t **identity); int tor_tls_check_lifetime(tor_tls_t *tls, int tolerance); int tor_tls_read(tor_tls_t *tls, char *cp, size_t len);

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[tor/master] More functions to manipulate certs received in cells
by nickm＠torproject.org 11 Oct '11

11 Oct '11

commit f4c1fa2a04c310c4e0274129bb2fff2aacb59248 Author: Nick Mathewson <nickm(a)torproject.org> Date: Wed Sep 14 13:04:48 2011 -0400 More functions to manipulate certs received in cells --- src/common/tortls.c | 118 +++++++++++++++++++++++++++++++++++++++++++++------ src/common/tortls.h | 3 + 2 files changed, 108 insertions(+), 13 deletions(-) diff --git a/src/common/tortls.c b/src/common/tortls.c index 2b12eea..0ba47ba 100644 --- a/src/common/tortls.c +++ b/src/common/tortls.c @@ -207,6 +207,7 @@ static int tor_tls_context_init_one(tor_tls_context_t **ppcontext, unsigned int key_lifetime); static tor_tls_context_t *tor_tls_context_new(crypto_pk_env_t *identity, unsigned int key_lifetime); +static int check_cert_lifetime_internal(const X509 *cert, int tolerance); /** Global TLS contexts. We keep them here because nobody else needs * to touch them. */ @@ -823,6 +824,84 @@ tor_tls_get_my_certs(int server, return 0; } +/** Return true iff a and b represent the same public key. */ +static int +pkey_eq(EVP_PKEY *a, EVP_PKEY *b) +{ + /* We'd like to do this, but openssl 0.9.7 doesn't have it: + return EVP_PKEY_cmp(a,b) == 1; + */ + unsigned char *a_enc=NULL, *b_enc=NULL, *a_ptr, *b_ptr; + int a_len1, b_len1, a_len2, b_len2, result; + a_len1 = i2d_PublicKey(a, NULL); + b_len1 = i2d_PublicKey(b, NULL); + if (a_len1 != b_len1) + return 0; + a_ptr = a_enc = tor_malloc(a_len1); + b_ptr = b_enc = tor_malloc(b_len1); + a_len2 = i2d_PublicKey(a, &a_ptr); + b_len2 = i2d_PublicKey(b, &b_ptr); + tor_assert(a_len2 == a_len1); + tor_assert(b_len2 == b_len1); + result = tor_memeq(a_enc, b_enc, a_len1); + tor_free(a_enc); + tor_free(b_enc); + return result; +} + +/** Return true iff the other side of tls has authenticated to us, and + * the key certified in cert is the same as the key they used to do it. + */ +int +tor_tls_cert_matches_key(const tor_tls_t *tls, const tor_cert_t *cert) +{ + X509 *peercert = SSL_get_peer_certificate(tls->ssl); + EVP_PKEY *link_key = NULL, *cert_key = NULL; + int result; + + if (!peercert) + return 0; + link_key = X509_get_pubkey(peercert); + cert_key = X509_get_pubkey(cert->cert); + + result = link_key && cert_key && pkey_eq(cert_key, link_key); + + X509_free(peercert); + if (link_key) + EVP_PKEY_free(link_key); + if (cert_key) + EVP_PKEY_free(cert_key); + + return result; +} + +/** Check wither cert is well-formed, currently live, and correctly + * signed by the public key in signing_cert. Return 0 if the cert is + * good, and -1 if it's bad or we couldn't check it. */ +int +tor_tls_cert_is_valid(const tor_cert_t *cert, + const tor_cert_t *signing_cert) +{ + EVP_PKEY *signing_key = X509_get_pubkey(signing_cert->cert); + int r; + if (!signing_key) + return 0; + r = X509_verify(cert->cert, signing_key); + EVP_PKEY_free(signing_key); + if (r <= 0) + return 0; + + /* okay, the signature checked out right. Now let's check the check the + * lifetime. */ + /*XXXX tolerance might be iffy here */ + if (check_cert_lifetime_internal(cert->cert, 60*60) < 0) + return 0; + + /* XXXX compare DNs or anything? */ + + return -1; +} + /** Increase the reference count of ctx. */ static void tor_tls_context_incref(tor_tls_context_t *ctx) @@ -1709,7 +1788,7 @@ tor_tls_peer_has_cert(tor_tls_t *tls) /** Warn that a certificate lifetime extends through a certain range. */ static void -log_cert_lifetime(X509 *cert, const char *problem) +log_cert_lifetime(const X509 *cert, const char *problem) { BIO *bio = NULL; BUF_MEM *buf; @@ -1856,25 +1935,14 @@ tor_tls_verify(int severity, tor_tls_t *tls, crypto_pk_env_t **identity_key) int tor_tls_check_lifetime(tor_tls_t *tls, int tolerance) { - time_t now, t; X509 *cert; int r = -1; - now = time(NULL); - if (!(cert = SSL_get_peer_certificate(tls->ssl))) goto done; - t = now + tolerance; - if (X509_cmp_time(X509_get_notBefore(cert), &t) > 0) { - log_cert_lifetime(cert, "not yet valid"); + if (check_cert_lifetime_internal(cert, tolerance) < 0) goto done; - } - t = now - tolerance; - if (X509_cmp_time(X509_get_notAfter(cert), &t) < 0) { - log_cert_lifetime(cert, "already expired"); - goto done; - } r = 0; done: @@ -1886,6 +1954,30 @@ tor_tls_check_lifetime(tor_tls_t *tls, int tolerance) return r; } +/** Helper: check whether cert is currently live, give or take + * tolerance seconds. If it is live, return 0. If it is not live, + * log a message and return -1. */ +static int +check_cert_lifetime_internal(const X509 *cert, int tolerance) +{ + time_t now, t; + + now = time(NULL); + + t = now + tolerance; + if (X509_cmp_time(X509_get_notBefore(cert), &t) > 0) { + log_cert_lifetime(cert, "not yet valid"); + return -1; + } + t = now - tolerance; + if (X509_cmp_time(X509_get_notAfter(cert), &t) < 0) { + log_cert_lifetime(cert, "already expired"); + return -1; + } + + return 0; +} + /** Return the number of bytes available for reading from tls. */ int diff --git a/src/common/tortls.h b/src/common/tortls.h index a6aed29..36309af 100644 --- a/src/common/tortls.h +++ b/src/common/tortls.h @@ -115,6 +115,9 @@ void tor_cert_get_der(const tor_cert_t *cert, int tor_tls_get_my_certs(int server, const tor_cert_t **link_cert_out, const tor_cert_t **id_cert_out); +int tor_tls_cert_matches_key(const tor_tls_t *tls, const tor_cert_t *cert); +int tor_tls_cert_is_valid(const tor_cert_t *cert, + const tor_cert_t *signing_cert); #endif

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[tor/master] Function to get digests of the certs and their keys
by nickm＠torproject.org 11 Oct '11

11 Oct '11

commit 8c9fdecfe9e6c93e678a5917e302aa18ada8a3b6 Author: Nick Mathewson <nickm(a)torproject.org> Date: Wed Sep 14 14:43:44 2011 -0400 Function to get digests of the certs and their keys --- src/common/tortls.c | 14 ++++++++++++++ src/common/tortls.h | 2 ++ 2 files changed, 16 insertions(+), 0 deletions(-) diff --git a/src/common/tortls.c b/src/common/tortls.c index 0ba47ba..1435223 100644 --- a/src/common/tortls.c +++ b/src/common/tortls.c @@ -789,6 +789,20 @@ tor_cert_get_der(const tor_cert_t *cert, *size_out = cert->encoded_len; } +/** Return a set of digests for the public key in cert. */ +const digests_t * +tor_cert_get_id_digests(const tor_cert_t *cert) +{ + return &cert->pkey_digests; +} + +/** Return a set of digests for the public key in cert. */ +const digests_t * +tor_cert_get_cert_digests(const tor_cert_t *cert) +{ + return &cert->cert_digests; +} + /** Remove a reference to ctx, and free it if it has no more * references. */ static void diff --git a/src/common/tortls.h b/src/common/tortls.h index 36309af..40eb830 100644 --- a/src/common/tortls.h +++ b/src/common/tortls.h @@ -112,6 +112,8 @@ void tor_cert_free(tor_cert_t *cert); tor_cert_t *tor_cert_decode(const uint8_t *certificate, size_t certificate_len); void tor_cert_get_der(const tor_cert_t *cert, const uint8_t **encoded_out, size_t *size_out); +const digests_t *tor_cert_get_id_digests(const tor_cert_t *cert); +const digests_t *tor_cert_get_cert_digests(const tor_cert_t *cert); int tor_tls_get_my_certs(int server, const tor_cert_t **link_cert_out, const tor_cert_t **id_cert_out);

1 0

[tor/master] Add AUTH keys as specified in proposal 176
by nickm＠torproject.org 11 Oct '11

11 Oct '11

commit a6fc5059cdb3263c0053ac76c39bef43a61269cc Author: Nick Mathewson <nickm(a)torproject.org> Date: Fri Sep 16 11:21:30 2011 -0400 Add AUTH keys as specified in proposal 176 Our keys and x.509 certs are proliferating here. Previously we had: An ID cert (using the main ID key), self-signed A link cert (using a shorter-term link key), signed by the ID key Once proposal 176 and 179 are done, we will also have: Optionally, a presentation cert (using the link key), signed by whomever. An authentication cert (using a shorter-term ID key), signed by the ID key. These new keys are managed as part of the tls context infrastructure, since you want to rotate them under exactly the same circumstances, and since they need X509 certificates. --- src/common/tortls.c | 46 ++++++++++++++++++++++++++++++++++------------ 1 files changed, 34 insertions(+), 12 deletions(-) diff --git a/src/common/tortls.c b/src/common/tortls.c index 5d36fd0..e275307 100644 --- a/src/common/tortls.c +++ b/src/common/tortls.c @@ -112,9 +112,11 @@ struct tor_cert_t { typedef struct tor_tls_context_t { int refcnt; SSL_CTX *ctx; - tor_cert_t *my_cert; + tor_cert_t *my_link_cert; tor_cert_t *my_id_cert; - crypto_pk_env_t *key; + tor_cert_t *my_auth_cert; + crypto_pk_env_t *link_key; + crypto_pk_env_t *auth_key; } tor_tls_context_t; #define TOR_TLS_MAGIC 0x71571571 @@ -811,9 +813,11 @@ tor_tls_context_decref(tor_tls_context_t *ctx) tor_assert(ctx); if (--ctx->refcnt == 0) { SSL_CTX_free(ctx->ctx); - tor_cert_free(ctx->my_cert); + tor_cert_free(ctx->my_link_cert); tor_cert_free(ctx->my_id_cert); - crypto_free_pk_env(ctx->key); + tor_cert_free(ctx->my_auth_cert); + crypto_free_pk_env(ctx->link_key); + crypto_free_pk_env(ctx->auth_key); tor_free(ctx); } } @@ -832,7 +836,7 @@ tor_tls_get_my_certs(int server, if (! ctx) return -1; if (link_cert_out) - *link_cert_out = ctx->my_cert; + *link_cert_out = server ? ctx->my_link_cert : ctx->my_auth_cert; if (id_cert_out) *id_cert_out = ctx->my_id_cert; return 0; @@ -1050,37 +1054,48 @@ tor_tls_context_init_one(tor_tls_context_t **ppcontext, static tor_tls_context_t * tor_tls_context_new(crypto_pk_env_t *identity, unsigned int key_lifetime) { - crypto_pk_env_t *rsa = NULL; + crypto_pk_env_t *rsa = NULL, *rsa_auth = NULL; EVP_PKEY *pkey = NULL; tor_tls_context_t *result = NULL; - X509 *cert = NULL, *idcert = NULL; + X509 *cert = NULL, *idcert = NULL, *authcert = NULL; char *nickname = NULL, *nn2 = NULL; tor_tls_init(); nickname = crypto_random_hostname(8, 20, "www.", ".net"); nn2 = crypto_random_hostname(8, 20, "www.", ".net"); - /* Generate short-term RSA key. */ + /* Generate short-term RSA key for use with TLS. */ if (!(rsa = crypto_new_pk_env())) goto error; if (crypto_pk_generate_key(rsa)<0) goto error; - /* Create certificate signed by identity key. */ + /* Generate short-term RSA key for use in the in-protocol ("v3") + * authentication handshake. */ + if (!(rsa_auth = crypto_new_pk_env())) + goto error; + if (crypto_pk_generate_key(rsa_auth)<0) + goto error; + /* Create a link certificate signed by identity key. */ cert = tor_tls_create_certificate(rsa, identity, nickname, nn2, key_lifetime); /* Create self-signed certificate for identity key. */ idcert = tor_tls_create_certificate(identity, identity, nn2, nn2, IDENTITY_CERT_LIFETIME); - if (!cert || !idcert) { + /* Create an authentication certificate signed by identity key. */ + authcert = tor_tls_create_certificate(rsa_auth, identity, nickname, nn2, + key_lifetime); + if (!cert || !idcert || !authcert) { log(LOG_WARN, LD_CRYPTO, "Error creating certificate"); goto error; } result = tor_malloc_zero(sizeof(tor_tls_context_t)); result->refcnt = 1; - result->my_cert = tor_cert_new(X509_dup(cert)); + result->my_link_cert = tor_cert_new(X509_dup(cert)); result->my_id_cert = tor_cert_new(X509_dup(idcert)); - result->key = crypto_pk_dup_key(rsa); + result->my_auth_cert = tor_cert_new(X509_dup(authcert)); + result->link_key = crypto_pk_dup_key(rsa); + result->auth_key = crypto_pk_dup_key(rsa_auth); #ifdef EVERYONE_HAS_AES /* Tell OpenSSL to only use TLS1 */ @@ -1146,6 +1161,9 @@ tor_tls_context_new(crypto_pk_env_t *identity, unsigned int key_lifetime) if (rsa) crypto_free_pk_env(rsa); + if (rsa_auth) + crypto_free_pk_env(rsa_auth); + X509_free(authcert); tor_free(nickname); tor_free(nn2); return result; @@ -1158,12 +1176,16 @@ tor_tls_context_new(crypto_pk_env_t *identity, unsigned int key_lifetime) EVP_PKEY_free(pkey); if (rsa) crypto_free_pk_env(rsa); + if (rsa_auth) + crypto_free_pk_env(rsa_auth); if (result) tor_tls_context_decref(result); if (cert) X509_free(cert); if (idcert) X509_free(idcert); + if (authcert) + X509_free(authcert); return NULL; }

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[tor/master] New function to get all digests of a public key
by nickm＠torproject.org 11 Oct '11

11 Oct '11

commit dcf69a9e12d013563575e50b7d6f547832f92f66 Author: Nick Mathewson <nickm(a)torproject.org> Date: Tue Sep 13 14:32:51 2011 -0400 New function to get all digests of a public key --- src/common/crypto.c | 26 ++++++++++++++++++++++++++ src/common/crypto.h | 1 + 2 files changed, 27 insertions(+), 0 deletions(-) diff --git a/src/common/crypto.c b/src/common/crypto.c index 9ad7575..edb0d42 100644 --- a/src/common/crypto.c +++ b/src/common/crypto.c @@ -1249,6 +1249,32 @@ crypto_pk_get_digest(crypto_pk_env_t *pk, char *digest_out) return 0; } +/** Compute all digests of the DER encoding of pk, and store them + * in digests_out. Return 0 on success, -1 on failure. */ +int +crypto_pk_get_all_digests(crypto_pk_env_t *pk, digests_t *digests_out) +{ + unsigned char *buf, *bufp; + int len; + + len = i2d_RSAPublicKey(pk->key, NULL); + if (len < 0) + return -1; + buf = bufp = tor_malloc(len+1); + len = i2d_RSAPublicKey(pk->key, &bufp); + if (len < 0) { + crypto_log_errors(LOG_WARN,"encoding public key"); + tor_free(buf); + return -1; + } + if (crypto_digest_all(digests_out, (char*)buf, len) < 0) { + tor_free(buf); + return -1; + } + tor_free(buf); + return 0; +} + /** Copy in to the outlen-byte buffer out, adding spaces * every four spaces. */ /* static */ void diff --git a/src/common/crypto.h b/src/common/crypto.h index 9b4eee6..d50d9f9 100644 --- a/src/common/crypto.h +++ b/src/common/crypto.h @@ -150,6 +150,7 @@ int crypto_pk_private_hybrid_decrypt(crypto_pk_env_t *env, char *to, int crypto_pk_asn1_encode(crypto_pk_env_t *pk, char *dest, size_t dest_len); crypto_pk_env_t *crypto_pk_asn1_decode(const char *str, size_t len); int crypto_pk_get_digest(crypto_pk_env_t *pk, char *digest_out); +int crypto_pk_get_all_digests(crypto_pk_env_t *pk, digests_t *digests_out); int crypto_pk_get_fingerprint(crypto_pk_env_t *pk, char *fp_out,int add_space); int crypto_pk_check_fingerprint_syntax(const char *s);

1 0

[tor/master] Cell types and states for new OR handshake
by nickm＠torproject.org 11 Oct '11

11 Oct '11

commit 1b0645acba905c37759194c222aacbbe40771223 Author: Nick Mathewson <nickm(a)torproject.org> Date: Tue Sep 13 10:03:09 2011 -0400 Cell types and states for new OR handshake Also, define all commands > 128 as variable-length when using v3 or later link protocol. Running into a var cell with an unrecognized type is no longer a bug. --- src/or/buffers.c | 38 ++++++++++++++++++++++++++++---------- src/or/command.c | 11 +++++------ src/or/connection.c | 9 ++++++--- src/or/connection_or.c | 6 +++--- src/or/or.h | 32 +++++++++++++++++++------------- 5 files changed, 61 insertions(+), 35 deletions(-) diff --git a/src/or/buffers.c b/src/or/buffers.c index 1025ced..c589fba 100644 --- a/src/or/buffers.c +++ b/src/or/buffers.c @@ -1005,6 +1005,32 @@ fetch_from_buf(char *string, size_t string_len, buf_t *buf) return (int)buf->datalen; } +/** True iff the cell command command is one that implies a variable-length + * cell in Tor link protocol linkproto. */ +static inline int +cell_command_is_var_length(uint8_t command, int linkproto) +{ + /* If linkproto is v2 (2), CELL_VERSIONS is the only variable-length cells work as + * implemented here. If it's 1, there are no variable-length cells. Tor + * does not support other versions right now, and so can't negotiate them. + */ + switch (linkproto) { + case 1: + /* Link protocol version 1 has no variable-length cells. */ + return 0; + case 2: + /* In link protocol version 2, VERSIONS is the only variable-length cell */ + return command == CELL_VERSIONS; + case 0: + case 3: + default: + /* In link protocol version 3 and later, and in version "unknown", + * commands 128 and higher indicate variable-length. VERSIONS is + * grandfathered in. */ + return command == CELL_VERSIONS || command >= 128; + } +} + /** Check buf for a variable-length cell according to the rules of link * protocol version linkproto. If one is found, pull it off the buffer * and assign a newly allocated var_cell_t to *out, and return 1. @@ -1019,12 +1045,6 @@ fetch_var_cell_from_buf(buf_t *buf, var_cell_t **out, int linkproto) var_cell_t *result; uint8_t command; uint16_t length; - /* If linkproto is unknown (0) or v2 (2), variable-length cells work as - * implemented here. If it's 1, there are no variable-length cells. Tor - * does not support other versions right now, and so can't negotiate them. - */ - if (linkproto == 1) - return 0; check(); *out = NULL; if (buf->datalen < VAR_CELL_HEADER_SIZE) @@ -1032,7 +1052,7 @@ fetch_var_cell_from_buf(buf_t *buf, var_cell_t **out, int linkproto) peek_from_buf(hdr, sizeof(hdr), buf); command = get_uint8(hdr+2); - if (!(CELL_COMMAND_IS_VAR_LENGTH(command))) + if (!(cell_command_is_var_length(command, linkproto))) return 0; length = ntohs(get_uint16(hdr+3)); @@ -1101,8 +1121,6 @@ fetch_var_cell_from_evbuffer(struct evbuffer *buf, var_cell_t **out, uint16_t cell_length; var_cell_t *cell; int result = 0; - if (linkproto == 1) - return 0; *out = NULL; buf_len = evbuffer_get_length(buf); @@ -1113,7 +1131,7 @@ fetch_var_cell_from_evbuffer(struct evbuffer *buf, var_cell_t **out, tor_assert(n >= VAR_CELL_HEADER_SIZE); command = get_uint8(hdr+2); - if (!(CELL_COMMAND_IS_VAR_LENGTH(command))) { + if (!(cell_command_is_var_length(command, linkproto))) { goto done; } diff --git a/src/or/command.c b/src/or/command.c index d24373e..72d8cd7 100644 --- a/src/or/command.c +++ b/src/or/command.c @@ -93,7 +93,7 @@ command_time_process_cell(cell_t *cell, or_connection_t *conn, int *time, void command_process_cell(cell_t *cell, or_connection_t *conn) { - int handshaking = (conn->_base.state == OR_CONN_STATE_OR_HANDSHAKING); + int handshaking = (conn->_base.state == OR_CONN_STATE_OR_HANDSHAKING_V2); #ifdef KEEP_TIMING_STATS /* how many of each cell have we seen so far this second? needs better * name. */ @@ -207,7 +207,7 @@ command_process_var_cell(var_cell_t *cell, or_connection_t *conn) #endif /* reject all when not handshaking. */ - if (conn->_base.state != OR_CONN_STATE_OR_HANDSHAKING) + if (conn->_base.state != OR_CONN_STATE_OR_HANDSHAKING_V2) return; switch (cell->command) { @@ -216,10 +216,9 @@ command_process_var_cell(var_cell_t *cell, or_connection_t *conn) PROCESS_CELL(versions, cell, conn); break; default: - log_warn(LD_BUG, + log_fn(LOG_INFO, LD_PROTOCOL, "Variable-length cell of unknown type (%d) received.", cell->command); - tor_fragile_assert(); break; } } @@ -506,7 +505,7 @@ command_process_versions_cell(var_cell_t *cell, or_connection_t *conn) int highest_supported_version = 0; const uint8_t *cp, *end; if (conn->link_proto != 0 || - conn->_base.state != OR_CONN_STATE_OR_HANDSHAKING || + conn->_base.state != OR_CONN_STATE_OR_HANDSHAKING_V2 || (conn->handshake_state && conn->handshake_state->received_versions)) { log_fn(LOG_PROTOCOL_WARN, LD_OR, "Received a VERSIONS cell on a connection with its version " @@ -572,7 +571,7 @@ command_process_netinfo_cell(cell_t *cell, or_connection_t *conn) conn->link_proto == 0 ? "non-versioned" : "a v1"); return; } - if (conn->_base.state != OR_CONN_STATE_OR_HANDSHAKING) { + if (conn->_base.state != OR_CONN_STATE_OR_HANDSHAKING_V2) { log_fn(LOG_PROTOCOL_WARN, LD_OR, "Received a NETINFO cell on non-handshaking connection; dropping."); return; diff --git a/src/or/connection.c b/src/or/connection.c index 45a1271..2bd2d07 100644 --- a/src/or/connection.c +++ b/src/or/connection.c @@ -140,10 +140,13 @@ conn_state_to_string(int type, int state) case OR_CONN_STATE_PROXY_HANDSHAKING: return "handshaking (proxy)"; case OR_CONN_STATE_TLS_HANDSHAKING: return "handshaking (TLS)"; case OR_CONN_STATE_TLS_CLIENT_RENEGOTIATING: - return "renegotiating (TLS)"; + return "renegotiating (TLS, v2 handshake)"; case OR_CONN_STATE_TLS_SERVER_RENEGOTIATING: - return "waiting for renegotiation (TLS)"; - case OR_CONN_STATE_OR_HANDSHAKING: return "handshaking (Tor)"; + return "waiting for renegotiation or V3 handshake"; + case OR_CONN_STATE_OR_HANDSHAKING_V2: + return "handshaking (Tor, v2 handshake)"; + case OR_CONN_STATE_OR_HANDSHAKING_V3: + return "handshaking (Tor, v3 handshake)"; case OR_CONN_STATE_OPEN: return "open"; } break; diff --git a/src/or/connection_or.c b/src/or/connection_or.c index 29f0f8d..b146efb 100644 --- a/src/or/connection_or.c +++ b/src/or/connection_or.c @@ -387,7 +387,7 @@ connection_or_process_inbuf(or_connection_t *conn) /* fall through. */ #endif case OR_CONN_STATE_OPEN: - case OR_CONN_STATE_OR_HANDSHAKING: + case OR_CONN_STATE_OR_HANDSHAKING_V2: return connection_or_process_cells_from_inbuf(conn); default: return 0; /* don't do anything */ @@ -439,7 +439,7 @@ connection_or_finished_flushing(or_connection_t *conn) switch (conn->_base.state) { case OR_CONN_STATE_PROXY_HANDSHAKING: case OR_CONN_STATE_OPEN: - case OR_CONN_STATE_OR_HANDSHAKING: + case OR_CONN_STATE_OR_HANDSHAKING_V2: break; default: log_err(LD_BUG,"Called in unexpected state %d.", conn->_base.state); @@ -1476,7 +1476,7 @@ connection_tls_finish_handshake(or_connection_t *conn) tor_tls_block_renegotiation(conn->tls); return connection_or_set_state_open(conn); } else { - conn->_base.state = OR_CONN_STATE_OR_HANDSHAKING; + conn->_base.state = OR_CONN_STATE_OR_HANDSHAKING_V2; if (connection_init_or_handshake_state(conn, started_here) < 0) return -1; if (!started_here) { diff --git a/src/or/or.h b/src/or/or.h index d6eaeb6..ef4ddbd 100644 --- a/src/or/or.h +++ b/src/or/or.h @@ -283,22 +283,27 @@ typedef enum { #define OR_CONN_STATE_CONNECTING 1 /** State for a connection to an OR: waiting for proxy handshake to complete */ #define OR_CONN_STATE_PROXY_HANDSHAKING 2 -/** State for a connection to an OR or client: SSL is handshaking, not done +/** State for an OR connection client: SSL is handshaking, not done * yet. */ #define OR_CONN_STATE_TLS_HANDSHAKING 3 /** State for a connection to an OR: We're doing a second SSL handshake for - * renegotiation purposes. */ + * renegotiation purposes. (V2 handshake only.) */ #define OR_CONN_STATE_TLS_CLIENT_RENEGOTIATING 4 /** State for a connection at an OR: We're waiting for the client to - * renegotiate. */ + * renegotiate (to indicate a v2 handshake) or send a versions cell (to + * indicate a v3 handshake) */ #define OR_CONN_STATE_TLS_SERVER_RENEGOTIATING 5 -/** State for a connection to an OR: We're done with our SSL handshake, but we - * haven't yet negotiated link protocol versions and sent a netinfo cell. - */ -#define OR_CONN_STATE_OR_HANDSHAKING 6 -/** State for a connection to an OR: Ready to send/receive cells. */ -#define OR_CONN_STATE_OPEN 7 -#define _OR_CONN_STATE_MAX 7 +/** State for an OR connection: We're done with our SSL handshake, we've done + * renegotiation, but we haven't yet negotiated link protocol versions and + * sent a netinfo cell. */ +#define OR_CONN_STATE_OR_HANDSHAKING_V2 6 +/** State for an OR connection: We're done with our SSL handshake, but we + * haven't yet negotiated link protocol versions, done a V3 handshake, and + * sent a netinfo cell. */ +#define OR_CONN_STATE_OR_HANDSHAKING_V3 7 +/** State for an OR connection:: Ready to send/receive cells. */ +#define OR_CONN_STATE_OPEN 8 +#define _OR_CONN_STATE_MAX 8 #define _EXIT_CONN_STATE_MIN 1 /** State for an exit connection: waiting for response from DNS farm. */ @@ -820,9 +825,10 @@ typedef enum { #define CELL_NETINFO 8 #define CELL_RELAY_EARLY 9 -/** True iff the cell command x is one that implies a variable-length - * cell. */ -#define CELL_COMMAND_IS_VAR_LENGTH(x) ((x) == CELL_VERSIONS) +#define CELL_VPADDING 128 +#define CELL_CERT 129 +#define CELL_AUTH_CHALLENGE 130 +#define CELL_AUTHENTICATE 131 /** How long to test reachability before complaining to the user. */ #define TIMEOUT_UNTIL_UNREACHABILITY_COMPLAINT (20*60)

1 0

[tor/master] Add a sha256 hmac function, with tests
by nickm＠torproject.org 11 Oct '11

11 Oct '11

commit fdbb9cdf746bbf0c39c34188baa8872471183ff7 Author: Nick Mathewson <nickm(a)torproject.org> Date: Tue Sep 13 11:38:13 2011 -0400 Add a sha256 hmac function, with tests --- src/common/crypto.c | 68 +++++++++++++++++++++++++++++++++++++++++++++ src/common/crypto.h | 3 ++ src/test/test_crypto.c | 71 +++++++++++++++++++++++++++++++++++++++++++++++- 3 files changed, 141 insertions(+), 1 deletions(-) diff --git a/src/common/crypto.c b/src/common/crypto.c index edb0d42..c397199 100644 --- a/src/common/crypto.c +++ b/src/common/crypto.c @@ -1740,6 +1740,74 @@ crypto_hmac_sha1(char *hmac_out, (unsigned char*)hmac_out, NULL); } +/** Compute the HMAC-SHA-256 of the msg_len bytes in msg, using + * the key of length key_len. Store the DIGEST_LEN-byte result + * in hmac_out. + */ +void +crypto_hmac_sha256(char *hmac_out, + const char *key, size_t key_len, + const char *msg, size_t msg_len) +{ +#if (OPENSSL_VERSION_NUMBER >= 0x00908000l) + /* If we've got OpenSSL >=0.9.8 we can use its hmac implementation. */ + tor_assert(key_len < INT_MAX); + tor_assert(msg_len < INT_MAX); + HMAC(EVP_sha256(), key, (int)key_len, (unsigned char*)msg, (int)msg_len, + (unsigned char*)hmac_out, NULL); +#else + /* OpenSSL doesn't have an EVP implementation for SHA256. We'll need + to do HMAC on our own. + + HMAC isn't so hard: To compute HMAC(key, msg): + 1. If len(key) > blocksize, key = H(key). + 2. If len(key) < blocksize, right-pad key up to blocksize with 0 bytes. + 3. let ipad = key xor 0x363636363636....36 + let opad = key xor 0x5c5c5c5c5c5c....5c + The result is H(opad | H( ipad | msg ) ) + */ +#define BLOCKSIZE 64 +#define DIGESTSIZE 32 + uint8_t k[BLOCKSIZE]; + uint8_t pad[BLOCKSIZE]; + uint8_t d[DIGESTSIZE]; + int i; + SHA256_CTX st; + + tor_assert(key_len < INT_MAX); + tor_assert(msg_len < INT_MAX); + + if (key_len <= BLOCKSIZE) { + memset(k, 0, sizeof(k)); + memcpy(k, key, key_len); /* not time invariant in key_len */ + } else { + SHA256((const uint8_t *)key, key_len, k); + memset(k+DIGESTSIZE, 0, sizeof(k)-DIGESTSIZE); + } + for (i = 0; i < BLOCKSIZE; ++i) + pad[i] = k[i] ^ 0x36; + SHA256_Init(&st); + SHA256_Update(&st, pad, BLOCKSIZE); + SHA256_Update(&st, (uint8_t*)msg, msg_len); + SHA256_Final(d, &st); + + for (i = 0; i < BLOCKSIZE; ++i) + pad[i] = k[i] ^ 0x5c; + SHA256_Init(&st); + SHA256_Update(&st, pad, BLOCKSIZE); + SHA256_Update(&st, d, DIGESTSIZE); + SHA256_Final((uint8_t*)hmac_out, &st); + + /* Now clear everything. */ + memset(k, 0, sizeof(k)); + memset(pad, 0, sizeof(pad)); + memset(d, 0, sizeof(d)); + memset(&st, 0, sizeof(st)); +#undef BLOCKSIZE +#undef DIGESTSIZE +#endif +} + /* DH */ /** Shared P parameter for our circuit-crypto DH key exchanges. */ diff --git a/src/common/crypto.h b/src/common/crypto.h index d50d9f9..80c1029 100644 --- a/src/common/crypto.h +++ b/src/common/crypto.h @@ -196,6 +196,9 @@ void crypto_digest_assign(crypto_digest_env_t *into, void crypto_hmac_sha1(char *hmac_out, const char *key, size_t key_len, const char *msg, size_t msg_len); +void crypto_hmac_sha256(char *hmac_out, + const char *key, size_t key_len, + const char *msg, size_t msg_len); /* Key negotiation */ #define DH_TYPE_CIRCUIT 1 diff --git a/src/test/test_crypto.c b/src/test/test_crypto.c index dca0d3a..1b338a2 100644 --- a/src/test/test_crypto.c +++ b/src/test/test_crypto.c @@ -231,7 +231,7 @@ test_crypto_sha(void) { crypto_digest_env_t *d1 = NULL, *d2 = NULL; int i; - char key[80]; + char key[160]; char digest[32]; char data[50]; char d_out1[DIGEST_LEN], d_out2[DIGEST256_LEN]; @@ -276,6 +276,75 @@ test_crypto_sha(void) test_streq(hex_str(digest, 20), "AA4AE5E15272D00E95705637CE8A3B55ED402112"); + /* Test HMAC-SHA256 with test cases from wikipedia and RFC 4231 */ + + /* Case empty (wikipedia) */ + crypto_hmac_sha256(digest, "", 0, "", 0); + test_streq(hex_str(digest, 32), + "B613679A0814D9EC772F95D778C35FC5FF1697C493715653C6C712144292C5AD"); + + /* Case quick-brown (wikipedia) */ + crypto_hmac_sha256(digest, "key", 3, + "The quick brown fox jumps over the lazy dog", 43); + test_streq(hex_str(digest, 32), + "F7BC83F430538424B13298E6AA6FB143EF4D59A14946175997479DBC2D1A3CD8"); + + /* "Test Case 1" from RFC 4231 */ + memset(key, 0x0b, 20); + crypto_hmac_sha256(digest, key, 20, "Hi There", 8); + test_memeq_hex(digest, + "b0344c61d8db38535ca8afceaf0bf12b" + "881dc200c9833da726e9376c2e32cff7"); + + /* "Test Case 2" from RFC 4231 */ + memset(key, 0x0b, 20); + crypto_hmac_sha256(digest, "Jefe", 4, "what do ya want for nothing?", 28); + test_memeq_hex(digest, + "5bdcc146bf60754e6a042426089575c7" + "5a003f089d2739839dec58b964ec3843"); + + /* "Test case 3" from RFC 4231 */ + memset(key, 0xaa, 20); + memset(data, 0xdd, 50); + crypto_hmac_sha256(digest, key, 20, data, 50); + test_memeq_hex(digest, + "773ea91e36800e46854db8ebd09181a7" + "2959098b3ef8c122d9635514ced565fe"); + + /* "Test case 4" from RFC 4231 */ + base16_decode(key, 25, + "0102030405060708090a0b0c0d0e0f10111213141516171819", 50); + memset(data, 0xcd, 50); + crypto_hmac_sha256(digest, key, 25, data, 50); + test_memeq_hex(digest, + "82558a389a443c0ea4cc819899f2083a" + "85f0faa3e578f8077a2e3ff46729665b"); + + /* "Test case 5" from RFC 4231 */ + memset(key, 0x0c, 20); + crypto_hmac_sha256(digest, key, 20, "Test With Truncation", 20); + test_memeq_hex(digest, + "a3b6167473100ee06e0c796c2955552b"); + + /* "Test case 6" from RFC 4231 */ + memset(key, 0xaa, 131); + crypto_hmac_sha256(digest, key, 131, + "Test Using Larger Than Block-Size Key - Hash Key First", + 54); + test_memeq_hex(digest, + "60e431591ee0b67f0d8a26aacbf5b77f" + "8e0bc6213728c5140546040f0ee37f54"); + + /* "Test case 7" from RFC 4231 */ + memset(key, 0xaa, 131); + crypto_hmac_sha256(digest, key, 131, + "This is a test using a larger than block-size key and a " + "larger than block-size data. The key needs to be hashed " + "before being used by the HMAC algorithm.", 152); + test_memeq_hex(digest, + "9b09ffa71b942fcb27635fbcd5b0e944" + "bfdc63644f0713938a7f51535c3a35e2"); + /* Incremental digest code. */ d1 = crypto_new_digest_env(); test_assert(d1);

1 0

[tor/master] Functions to get a public RSA key from a cert
by nickm＠torproject.org 11 Oct '11

11 Oct '11

commit 0a4f56277290d4736db3b15dc4c2071000f7883f Author: Nick Mathewson <nickm(a)torproject.org> Date: Thu Sep 22 10:18:17 2011 -0400 Functions to get a public RSA key from a cert --- src/common/tortls.c | 34 ++++++++++++++++++++++++++++++++++ src/common/tortls.h | 2 ++ 2 files changed, 36 insertions(+), 0 deletions(-) diff --git a/src/common/tortls.c b/src/common/tortls.c index 332d784..5d36fd0 100644 --- a/src/common/tortls.c +++ b/src/common/tortls.c @@ -838,6 +838,40 @@ tor_tls_get_my_certs(int server, return 0; } +/** + * Return the authentication key that we use to authenticate ourselves as a + * client in the V3 in-protocol handshake. + */ +crypto_pk_env_t * +tor_tls_get_my_client_auth_key(void) +{ + if (! client_tls_context) + return NULL; + return client_tls_context->auth_key; +} + +/** + * Return the public key that a cetificate certifies. Return NULL if the + * cert's key is not RSA. + */ +crypto_pk_env_t * +tor_tls_cert_get_key(tor_cert_t *cert) +{ + crypto_pk_env_t *result = NULL; + EVP_PKEY *pkey = X509_get_pubkey(cert->cert); + RSA *rsa; + if (!pkey) + return NULL; + rsa = EVP_PKEY_get1_RSA(pkey); + if (!rsa) { + EVP_PKEY_free(pkey); + return NULL; + } + result = _crypto_new_pk_env_rsa(rsa); + EVP_PKEY_free(pkey); + return result; +} + /** Return true iff a and b represent the same public key. */ static int pkey_eq(EVP_PKEY *a, EVP_PKEY *b) diff --git a/src/common/tortls.h b/src/common/tortls.h index 70d24a5..b522dd1 100644 --- a/src/common/tortls.h +++ b/src/common/tortls.h @@ -118,6 +118,8 @@ const digests_t *tor_cert_get_cert_digests(const tor_cert_t *cert); int tor_tls_get_my_certs(int server, const tor_cert_t **link_cert_out, const tor_cert_t **id_cert_out); +crypto_pk_env_t *tor_tls_get_my_client_auth_key(void); +crypto_pk_env_t *tor_tls_cert_get_key(tor_cert_t *cert); int tor_tls_cert_matches_key(const tor_tls_t *tls, const tor_cert_t *cert); int tor_tls_cert_is_valid(const tor_cert_t *cert, const tor_cert_t *signing_cert);

1 0

[tor/master] Function to detect certificate types that signal v3 certificates
by nickm＠torproject.org 11 Oct '11

11 Oct '11

commit 92602345e001d8e66038d5d98cbb21eea5ef40c9 Author: Nick Mathewson <nickm(a)torproject.org> Date: Fri Sep 16 17:48:20 2011 -0400 Function to detect certificate types that signal v3 certificates --- src/common/tortls.c | 71 +++++++++++++++++++++++++++++++++++++++++++++++++++ src/common/tortls.h | 1 + 2 files changed, 72 insertions(+), 0 deletions(-) diff --git a/src/common/tortls.c b/src/common/tortls.c index 1435223..332d784 100644 --- a/src/common/tortls.c +++ b/src/common/tortls.c @@ -2075,6 +2075,77 @@ tor_tls_used_v1_handshake(tor_tls_t *tls) return 1; } +/** Return true iff name is a DN of a kind that could only + * occur in a v3-handshake-indicating certificate */ +static int +dn_indicates_v3_cert(X509_NAME *name) +{ + X509_NAME_ENTRY *entry; + int n_entries; + ASN1_OBJECT *obj; + ASN1_STRING *str; + unsigned char *s; + int len, r; + + n_entries = X509_NAME_entry_count(name); + if (n_entries != 1) + return 1; /* More than one entry in the DN. */ + entry = X509_NAME_get_entry(name, 0); + + obj = X509_NAME_ENTRY_get_object(entry); + if (OBJ_obj2nid(obj) != OBJ_txt2nid("commonName")) + return 1; /* The entry isn't a commonName. */ + + str = X509_NAME_ENTRY_get_data(entry); + len = ASN1_STRING_to_UTF8(&s, str); + if (len < 0) + return 0; + r = fast_memneq(s + len - 4, ".net", 4); + OPENSSL_free(s); + return r; +} + +/** Return true iff the peer certificate we're received on tls + * indicates that this connection should use the v3 (in-protocol) + * authentication handshake. + * + * Only the connection initiator should use this, and only once the initial + * handshake is done; the responder detects a v1 handshake by cipher types, + * and a v3/v2 handshake by Versions cell vs renegotiation. + */ +int +tor_tls_received_v3_certificate(tor_tls_t *tls) +{ + X509 *cert = SSL_get_peer_certificate(tls->ssl); + EVP_PKEY *key; + X509_NAME *issuer_name, *subject_name; + + if (!cert) { + log_warn(LD_BUG, "Called on a connection with no peer certificate"); + return 0; + } + + subject_name = X509_get_subject_name(cert); + issuer_name = X509_get_issuer_name(cert); + + if (X509_name_cmp(subject_name, issuer_name) == 0) + return 1; /* purportedly self signed */ + + if (dn_indicates_v3_cert(subject_name) || + dn_indicates_v3_cert(issuer_name)) + return 1; /* DN is fancy */ + + key = X509_get_pubkey(cert); + if (EVP_PKEY_bits(key) != 1024 || + EVP_PKEY_type(key->type) != EVP_PKEY_RSA) { + EVP_PKEY_free(key); + return 1; /* Key is fancy */ + } + + EVP_PKEY_free(key); + return 0; +} + /** Return the number of server handshakes that we've noticed doing on * tls. */ int diff --git a/src/common/tortls.h b/src/common/tortls.h index 40eb830..70d24a5 100644 --- a/src/common/tortls.h +++ b/src/common/tortls.h @@ -88,6 +88,7 @@ void tor_tls_get_buffer_sizes(tor_tls_t *tls, size_t *wbuf_capacity, size_t *wbuf_bytes); int tor_tls_used_v1_handshake(tor_tls_t *tls); +int tor_tls_received_v3_certificate(tor_tls_t *tls); int tor_tls_get_num_server_handshakes(tor_tls_t *tls); int tor_tls_server_got_renegotiate(tor_tls_t *tls); int tor_tls_get_tlssecrets(tor_tls_t *tls, uint8_t *secrets_out);

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