Merge branch 'bug22460_case2_029_01_squashed' into maint-0.2.9

5 files changed, 84 insertions, 14 deletions

diff --git a/changes/bug22460_case2 b/changes/bug22460_case2
new file mode 100644
index 0000000000..0a11759832
--- /dev/null
+++ b/changes/bug22460_case2
@@ -0,0 +1,8 @@
+  o Major bugfixes (relay, link handshake):
+
+    - When performing the v3 link handshake on a TLS connection, report that
+      we have the x509 certificate that we actually used on that connection,
+      even if we have changed certificates since that connection was first
+      opened. Previously, we would claim to have used our most recent x509
+      link certificate, which would sometimes make the link handshake fail.
+      Fixes one case of bug 22460; bugfix on 0.2.3.6-alpha.
diff --git a/src/common/tortls.c b/src/common/tortls.c
index 62ed5be344..d61cc2e58a 100644
--- a/src/common/tortls.c
+++ b/src/common/tortls.c
@@ -677,6 +677,15 @@ MOCK_IMPL(STATIC tor_x509_cert_t *,
   return cert;
 }
 
+/** Return a new copy of <b>cert</b>. */
+tor_x509_cert_t *
+tor_x509_cert_dup(const tor_x509_cert_t *cert)
+{
+  tor_assert(cert);
+  X509 *x509 = cert->cert;
+  return tor_x509_cert_new(X509_dup(x509));
+}
+
 /** Read a DER-encoded X509 cert, of length exactly <b>certificate_len</b>,
  * from a <b>certificate</b>.  Return a newly allocated tor_x509_cert_t on
  * success and NULL on failure. */
@@ -2009,7 +2018,8 @@ tor_tls_peer_has_cert(tor_tls_t *tls)
   return 1;
 }
 
-/** Return the peer certificate, or NULL if there isn't one. */
+/** Return a newly allocated copy of the peer certificate, or NULL if there
+ * isn't one. */
 MOCK_IMPL(tor_x509_cert_t *,
 tor_tls_get_peer_cert,(tor_tls_t *tls))
 {
@@ -2021,6 +2031,24 @@ tor_tls_get_peer_cert,(tor_tls_t *tls))
   return tor_x509_cert_new(cert);
 }
 
+/** Return a newly allocated copy of the cerficate we used on the connection,
+ * or NULL if somehow we didn't use one. */
+MOCK_IMPL(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 7c035a2cd5..f018c45c82 100644
--- a/src/common/tortls.h
+++ b/src/common/tortls.h
@@ -197,7 +197,9 @@ 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_x509_cert_t *tor_x509_cert_dup(const tor_x509_cert_t *cert);
 MOCK_DECL(tor_x509_cert_t *,tor_tls_get_peer_cert,(tor_tls_t *tls));
+MOCK_DECL(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 267c32dda4..3b35d5e34c 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 */
diff --git a/src/test/test_link_handshake.c b/src/test/test_link_handshake.c
index 6c0567098f..b979485967 100644
--- a/src/test/test_link_handshake.c
+++ b/src/test/test_link_handshake.c
@@ -66,6 +66,14 @@ mock_send_authenticate(or_connection_t *conn, int type)
   return 0;
 }
 
+static tor_x509_cert_t *mock_own_cert = NULL;
+static tor_x509_cert_t *
+mock_get_own_cert(tor_tls_t *tls)
+{
+  (void)tls;
+  return tor_x509_cert_dup(mock_own_cert);
+}
+
 /* Test good certs cells */
 static void
 test_link_handshake_certs_ok(void *arg)
@@ -84,6 +92,7 @@ test_link_handshake_certs_ok(void *arg)
   MOCK(tor_tls_cert_matches_key, mock_tls_cert_matches_key);
   MOCK(connection_or_write_var_cell_to_buf, mock_write_var_cell);
   MOCK(connection_or_send_netinfo, mock_send_netinfo);
+  MOCK(tor_tls_get_own_cert, mock_get_own_cert);
 
   key1 = pk_generate(2);
   key2 = pk_generate(3);
@@ -94,6 +103,12 @@ test_link_handshake_certs_ok(void *arg)
   tt_int_op(tor_tls_context_init(TOR_TLS_CTX_IS_PUBLIC_SERVER,
                                  key1, key2, 86400), ==, 0);
 
+  {
+    const tor_x509_cert_t *link = NULL;
+    tt_assert(!tor_tls_get_my_certs(1, &link, NULL));
+    mock_own_cert = tor_x509_cert_dup(link);
+  }
+
   c1->base_.state = OR_CONN_STATE_OR_HANDSHAKING_V3;
   c1->link_proto = 3;
   tt_int_op(connection_init_or_handshake_state(c1, 1), ==, 0);
@@ -174,6 +189,9 @@ test_link_handshake_certs_ok(void *arg)
   UNMOCK(tor_tls_cert_matches_key);
   UNMOCK(connection_or_write_var_cell_to_buf);
   UNMOCK(connection_or_send_netinfo);
+  UNMOCK(tor_tls_get_own_cert);
+  tor_x509_cert_free(mock_own_cert);
+  mock_own_cert = NULL;
   memset(c1->identity_digest, 0, sizeof(c1->identity_digest));
   memset(c2->identity_digest, 0, sizeof(c2->identity_digest));
   connection_free_(TO_CONN(c1));
@@ -656,11 +674,12 @@ AUTHCHALLENGE_FAIL(nonzero_circid,
                    d->cell->circ_id = 1337)
 
 static tor_x509_cert_t *mock_peer_cert = NULL;
+
 static tor_x509_cert_t *
 mock_get_peer_cert(tor_tls_t *tls)
 {
   (void)tls;
-  return mock_peer_cert;
+  return tor_x509_cert_dup(mock_peer_cert);
 }
 
 static int
@@ -694,6 +713,7 @@ authenticate_data_cleanup(const struct testcase_t *test, void *arg)
   (void) test;
   UNMOCK(connection_or_write_var_cell_to_buf);
   UNMOCK(tor_tls_get_peer_cert);
+  UNMOCK(tor_tls_get_own_cert);
   UNMOCK(tor_tls_get_tlssecrets);
   UNMOCK(connection_or_close_for_error);
   UNMOCK(channel_set_circid_type);
@@ -710,7 +730,10 @@ authenticate_data_cleanup(const struct testcase_t *test, void *arg)
     crypto_pk_free(d->key2);
     tor_free(d);
   }
+  tor_x509_cert_free(mock_peer_cert);
+  tor_x509_cert_free(mock_own_cert);
   mock_peer_cert = NULL;
+  mock_own_cert = NULL;
 
   return 1;
 }
@@ -724,6 +747,7 @@ authenticate_data_setup(const struct testcase_t *test)
 
   MOCK(connection_or_write_var_cell_to_buf, mock_write_var_cell);
   MOCK(tor_tls_get_peer_cert, mock_get_peer_cert);
+  MOCK(tor_tls_get_own_cert, mock_get_own_cert);
   MOCK(tor_tls_get_tlssecrets, mock_get_tlssecrets);
   MOCK(connection_or_close_for_error, mock_close_for_err);
   MOCK(channel_set_circid_type, mock_set_circid_type);
@@ -773,6 +797,8 @@ authenticate_data_setup(const struct testcase_t *test)
   tor_x509_cert_get_der(link_cert, &der, &sz);
   mock_peer_cert = tor_x509_cert_decode(der, sz);
   tt_assert(mock_peer_cert);
+  mock_own_cert = tor_x509_cert_decode(der, sz);
+  tt_assert(mock_own_cert);
   tt_assert(! tor_tls_get_my_certs(0, &auth_cert, &id_cert));
   tor_x509_cert_get_der(auth_cert, &der, &sz);
   d->c2->handshake_state->auth_cert = tor_x509_cert_decode(der, sz);