[tor-commits] [tor/release-0.2.1] Don't send a certificate chain on outgoing TLS connections from non-relays
arma at torproject.org
arma at torproject.org
Thu Oct 27 23:51:30 UTC 2011
commit 638fdedcf16cf7d6f7c586d36f7ef335c1c9714f
Author: Nick Mathewson <nickm at torproject.org>
Date: Sun Oct 23 16:06:06 2011 +0000
Don't send a certificate chain on outgoing TLS connections from non-relays
---
changes/issue-2011-10-19L | 12 ++++++
src/common/tortls.c | 93 ++++++++++++++++++++++++++-------------------
2 files changed, 66 insertions(+), 39 deletions(-)
diff --git a/changes/issue-2011-10-19L b/changes/issue-2011-10-19L
new file mode 100644
index 0000000..972823e
--- /dev/null
+++ b/changes/issue-2011-10-19L
@@ -0,0 +1,12 @@
+ 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.
+
diff --git a/src/common/tortls.c b/src/common/tortls.c
index c78a9ec..cc805f8 100644
--- a/src/common/tortls.c
+++ b/src/common/tortls.c
@@ -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;
@@ -711,22 +718,26 @@ tor_tls_context_new(crypto_pk_env_t *identity, unsigned int key_lifetime)
goto error;
if (crypto_pk_generate_key(rsa)<0)
goto error;
- /* Create 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) {
- log(LOG_WARN, LD_CRYPTO, "Error creating certificate");
- goto error;
+ if (!is_client) {
+ /* Create 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) {
+ 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 = X509_dup(cert);
- result->my_id_cert = X509_dup(idcert);
- result->key = crypto_pk_dup_key(rsa);
+ 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 */
@@ -758,27 +769,31 @@ 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 (cert && !SSL_CTX_use_certificate(result->ctx,cert))
- goto error;
- X509_free(cert); /* We just added a reference to cert. */
- cert=NULL;
- if (idcert) {
- X509_STORE *s = SSL_CTX_get_cert_store(result->ctx);
- tor_assert(s);
- X509_STORE_add_cert(s, idcert);
- X509_free(idcert); /* The context now owns the reference to idcert */
- idcert = NULL;
+ if (! is_client) {
+ if (cert && !SSL_CTX_use_certificate(result->ctx,cert))
+ goto error;
+ X509_free(cert); /* We just added a reference to cert. */
+ cert=NULL;
+ if (idcert) {
+ X509_STORE *s = SSL_CTX_get_cert_store(result->ctx);
+ tor_assert(s);
+ X509_STORE_add_cert(s, idcert);
+ 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);
- tor_assert(rsa);
- if (!(pkey = _crypto_pk_env_get_evp_pkey(rsa,1)))
- goto error;
- if (!SSL_CTX_use_PrivateKey(result->ctx, pkey))
- goto error;
- EVP_PKEY_free(pkey);
- pkey = NULL;
- if (!SSL_CTX_check_private_key(result->ctx))
- goto error;
+ if (!is_client) {
+ tor_assert(rsa);
+ if (!(pkey = _crypto_pk_env_get_evp_pkey(rsa,1)))
+ goto error;
+ if (!SSL_CTX_use_PrivateKey(result->ctx, pkey))
+ goto error;
+ EVP_PKEY_free(pkey);
+ 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));
More information about the tor-commits
mailing list