commit 50facb40bb42e070b858ca052edccd0f3a5b83b5 Author: Nick Mathewson nickm@torproject.org Date: Wed May 31 19:12:32 2017 -0400

On v3 link handshake, send the correct link certificate

Previously we'd send the _current_ link certificate, which would cause a handshaking failure when the TLS context rotated. --- src/common/tortls.c | 18 ++++++++++++++++++ src/common/tortls.h | 1 + src/or/connection_or.c | 30 ++++++++++++++++++------------ 3 files changed, 37 insertions(+), 12 deletions(-)

diff --git a/src/common/tortls.c b/src/common/tortls.c index 62ed5be..055b468 100644 --- a/src/common/tortls.c +++ b/src/common/tortls.c @@ -2021,6 +2021,24 @@ tor_tls_get_peer_cert,(tor_tls_t *tls)) return tor_x509_cert_new(cert); }

+/** Return the cerficate we used on the connection, or NULL if somehow + * we didn't use one. */ +tor_x509_cert_t * +tor_tls_get_own_cert(tor_tls_t *tls) +{ + X509 *cert = SSL_get_certificate(tls->ssl); + tls_log_errors(tls, LOG_WARN, LD_HANDSHAKE, + "getting own-connection certificate"); + if (!cert) + return NULL; + /* Fun inconsistency: SSL_get_peer_certificate increments the reference + * count, but SSL_get_certificate does not. */ + X509 *duplicate = X509_dup(cert); + if (BUG(duplicate == NULL)) + return NULL; + return tor_x509_cert_new(duplicate); +} + /** Warn that a certificate lifetime extends through a certain range. */ static void log_cert_lifetime(int severity, const X509 *cert, const char *problem) diff --git a/src/common/tortls.h b/src/common/tortls.h index 7c035a2..ae11b7a 100644 --- a/src/common/tortls.h +++ b/src/common/tortls.h @@ -198,6 +198,7 @@ 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); MOCK_DECL(tor_x509_cert_t *,tor_tls_get_peer_cert,(tor_tls_t *tls)); +tor_x509_cert_t *tor_tls_get_own_cert(tor_tls_t *tls); int tor_tls_verify(int severity, tor_tls_t *tls, crypto_pk_t **identity); int tor_tls_check_lifetime(int severity, tor_tls_t *tls, int past_tolerance, diff --git a/src/or/connection_or.c b/src/or/connection_or.c index 267c32d..3b35d5e 100644 --- a/src/or/connection_or.c +++ b/src/or/connection_or.c @@ -2137,7 +2137,9 @@ connection_or_send_netinfo,(or_connection_t *conn)) int connection_or_send_certs_cell(or_connection_t *conn) { - const tor_x509_cert_t *link_cert = NULL, *id_cert = NULL; + const tor_x509_cert_t *global_link_cert = NULL, *id_cert = NULL, + *using_link_cert = NULL; + tor_x509_cert_t *own_link_cert = NULL; const uint8_t *link_encoded = NULL, *id_encoded = NULL; size_t link_len, id_len; var_cell_t *cell; @@ -2149,9 +2151,15 @@ connection_or_send_certs_cell(or_connection_t *conn) if (! conn->handshake_state) return -1; const int conn_in_server_mode = ! conn->handshake_state->started_here; - if (tor_tls_get_my_certs(conn_in_server_mode, &link_cert, &id_cert) < 0) + if (tor_tls_get_my_certs(conn_in_server_mode, + &global_link_cert, &id_cert) < 0) return -1; - tor_x509_cert_get_der(link_cert, &link_encoded, &link_len); + if (conn_in_server_mode) { + using_link_cert = own_link_cert = tor_tls_get_own_cert(conn->tls); + } else { + using_link_cert = global_link_cert; + } + tor_x509_cert_get_der(using_link_cert, &link_encoded, &link_len); tor_x509_cert_get_der(id_cert, &id_encoded, &id_len);

cell_len = 1 /* 1 byte: num certs in cell */ + @@ -2179,6 +2187,7 @@ connection_or_send_certs_cell(or_connection_t *conn)

connection_or_write_var_cell_to_buf(cell, conn); var_cell_free(cell); + tor_x509_cert_free(own_link_cert);

return 0; } @@ -2258,10 +2267,10 @@ connection_or_compute_authenticate_cell_body(or_connection_t *conn, memcpy(auth1_getarray_type(auth), "AUTH0001", 8);

{ - const tor_x509_cert_t *id_cert=NULL, *link_cert=NULL; + 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, &link_cert, &id_cert)) + if (tor_tls_get_my_certs(server, NULL, &id_cert)) goto err; my_digests = tor_x509_cert_get_id_digests(id_cert); their_digests = @@ -2300,13 +2309,11 @@ connection_or_compute_authenticate_cell_body(or_connection_t *conn,

{ /* Digest of cert used on TLS link : 32 octets. */ - const tor_x509_cert_t *cert = NULL; - tor_x509_cert_t *freecert = NULL; + tor_x509_cert_t *cert = NULL; if (server) { - tor_tls_get_my_certs(1, &cert, NULL); + cert = tor_tls_get_own_cert(conn->tls); } else { - freecert = tor_tls_get_peer_cert(conn->tls); - cert = freecert; + cert = tor_tls_get_peer_cert(conn->tls); } if (!cert) { log_warn(LD_OR, "Unable to find cert when making AUTH1 data."); @@ -2316,8 +2323,7 @@ connection_or_compute_authenticate_cell_body(or_connection_t *conn, memcpy(auth->scert, tor_x509_cert_get_cert_digests(cert)->d[DIGEST_SHA256], 32);

- if (freecert) - tor_x509_cert_free(freecert); + tor_x509_cert_free(cert); }

/* HMAC of clientrandom and serverrandom using master key : 32 octets */