Don't send a certificate chain on outgoing TLS connections from non-relays (638fdedc) · Commits · Legacy / gitolite / user / andrea / Tor

changes/issue-2011-10-19L

0 → 100644

+12 −0

Original line number	Diff line number	Diff line
		o Security fixes:

		- Don't send TLS certificate chains on outgoing OR connections
		from clients and bridges. Previously, each client or bridge
		would use a single cert chain for all outgoing OR connections
		for up to 24 hours, which allowed any relay connected to by a
		client or bridge to determine which entry guards it is using.
		This is a potential user-tracing bug for all users; everyone
		who uses Tor's client or hidden service functionality should
		upgrade. Fixes CVE-2011-2768. Bugfix on FIXME; found by
		frosty_un.

src/common/tortls.c

+54 −39

Original line number	Diff line number	Diff line
		@@ -186,9 +186,11 @@ static X509* tor_tls_create_certificate(crypto_pk_env_t *rsa,
		static void tor_tls_unblock_renegotiation(tor_tls_t *tls);
		static int tor_tls_context_init_one(tor_tls_context_t **ppcontext,
		crypto_pk_env_t *identity,
		unsigned int key_lifetime);
		unsigned int key_lifetime,
		int is_client);
		static tor_tls_context_t tor_tls_context_new(crypto_pk_env_t identity,
		unsigned int key_lifetime);
		unsigned int key_lifetime,
		int is_client);

		/** Global TLS contexts. We keep them here because nobody else needs
		* to touch them. */
		@@ -624,7 +626,7 @@ tor_tls_context_init(int is_public_server,

		rv1 = tor_tls_context_init_one(&server_tls_context,
		server_identity,
		key_lifetime);
		key_lifetime, 0);

		if (rv1 >= 0) {
		new_ctx = server_tls_context;
		@@ -640,7 +642,8 @@ tor_tls_context_init(int is_public_server,
		if (server_identity != NULL) {
		rv1 = tor_tls_context_init_one(&server_tls_context,
		server_identity,
		key_lifetime);
		key_lifetime,
		0);
		} else {
		tor_tls_context_t *old_ctx = server_tls_context;
		server_tls_context = NULL;
		@@ -652,7 +655,8 @@ tor_tls_context_init(int is_public_server,

		rv2 = tor_tls_context_init_one(&client_tls_context,
		client_identity,
		key_lifetime);
		key_lifetime,
		1);
		}

		return rv1 < rv2 ? rv1 : rv2;
		@@ -669,10 +673,12 @@ tor_tls_context_init(int is_public_server,
		static int
		tor_tls_context_init_one(tor_tls_context_t **ppcontext,
		crypto_pk_env_t *identity,
		unsigned int key_lifetime)
		unsigned int key_lifetime,
		int is_client)
		{
		tor_tls_context_t *new_ctx = tor_tls_context_new(identity,
		key_lifetime);
		key_lifetime,
		is_client);
		tor_tls_context_t old_ctx = ppcontext;

		if (new_ctx != NULL) {
		@@ -694,7 +700,8 @@ tor_tls_context_init_one(tor_tls_context_t **ppcontext,
		* certificate.
		*/
		static tor_tls_context_t *
		tor_tls_context_new(crypto_pk_env_t *identity, unsigned int key_lifetime)
		tor_tls_context_new(crypto_pk_env_t *identity, unsigned int key_lifetime,
		int is_client)
		{
		crypto_pk_env_t *rsa = NULL;
		EVP_PKEY *pkey = NULL;
		@@ -711,6 +718,7 @@ tor_tls_context_new(crypto_pk_env_t *identity, unsigned int key_lifetime)
		goto error;
		if (crypto_pk_generate_key(rsa)<0)
		goto error;
		if (!is_client) {
		/* Create certificate signed by identity key. */
		cert = tor_tls_create_certificate(rsa, identity, nickname, nn2,
		key_lifetime);
		@@ -721,12 +729,15 @@ tor_tls_context_new(crypto_pk_env_t *identity, unsigned int key_lifetime)
		log(LOG_WARN, LD_CRYPTO, "Error creating certificate");
		goto error;
		}
		}

		result = tor_malloc_zero(sizeof(tor_tls_context_t));
		result->refcnt = 1;
		if (!is_client) {
		result->my_cert = X509_dup(cert);
		result->my_id_cert = X509_dup(idcert);
		result->key = crypto_pk_dup_key(rsa);
		}

		#ifdef EVERYONE_HAS_AES
		/* Tell OpenSSL to only use TLS1 */
		@@ -758,6 +769,7 @@ tor_tls_context_new(crypto_pk_env_t *identity, unsigned int key_lifetime)
		#ifdef SSL_MODE_RELEASE_BUFFERS
		SSL_CTX_set_mode(result->ctx, SSL_MODE_RELEASE_BUFFERS);
		#endif
		if (! is_client) {
		if (cert && !SSL_CTX_use_certificate(result->ctx,cert))
		goto error;
		X509_free(cert); /* We just added a reference to cert. */
		@@ -769,7 +781,9 @@ tor_tls_context_new(crypto_pk_env_t *identity, unsigned int key_lifetime)
		X509_free(idcert); /* The context now owns the reference to idcert */
		idcert = NULL;
		}
		}
		SSL_CTX_set_session_cache_mode(result->ctx, SSL_SESS_CACHE_OFF);
		if (!is_client) {
		tor_assert(rsa);
		if (!(pkey = _crypto_pk_env_get_evp_pkey(rsa,1)))
		goto error;
		@@ -779,6 +793,7 @@ tor_tls_context_new(crypto_pk_env_t *identity, unsigned int key_lifetime)
		pkey = NULL;
		if (!SSL_CTX_check_private_key(result->ctx))
		goto error;
		}
		{
		crypto_dh_env_t *dh = crypto_dh_new(DH_TYPE_TLS);
		SSL_CTX_set_tmp_dh(result->ctx, _crypto_dh_env_get_dh(dh));