diff options
| -rw-r--r-- | changes/trove-2017-009 | 10 | ||||
| -rw-r--r-- | changes/trove-2017-011 | 8 | ||||
| -rw-r--r-- | src/common/crypto.c | 16 | ||||
| -rw-r--r-- | src/or/rendservice.c | 4 |
4 files changed, 34 insertions, 4 deletions
diff --git a/changes/trove-2017-009 b/changes/trove-2017-009 new file mode 100644 index 0000000000..166a5faec6 --- /dev/null +++ b/changes/trove-2017-009 @@ -0,0 +1,10 @@ + o Major bugfixes (security): + - When checking for replays in the INTRODUCE1 cell data for a (legacy) + hiddden service, correctly detect replays in the RSA-encrypted part of + the cell. We were previously checking for replays on the entire cell, + but those can be circumvented due to the malleability of Tor's legacy + hybrid encryption. This fix helps prevent a traffic confirmation + attack. Fixes bug 24244; bugfix on 0.2.4.1-alpha. This issue is also + tracked as TROVE-2017-009 and CVE-2017-8819. + + diff --git a/changes/trove-2017-011 b/changes/trove-2017-011 new file mode 100644 index 0000000000..82d20d9e78 --- /dev/null +++ b/changes/trove-2017-011 @@ -0,0 +1,8 @@ + o Major bugfixes (security): + - Fix a denial of service bug where an attacker could use a malformed + directory object to cause a Tor instance to pause while OpenSSL would + try to read a passphrase from the terminal. (If the terminal was not + available, tor would continue running.) Fixes bug 24246; bugfix on + every version of Tor. Also tracked as TROVE-2017-011 and + CVE-2017-8821. Found by OSS-Fuzz as testcase 6360145429790720. + diff --git a/src/common/crypto.c b/src/common/crypto.c index f7362765d2..8d816652d3 100644 --- a/src/common/crypto.c +++ b/src/common/crypto.c @@ -592,11 +592,21 @@ crypto_pk_generate_key_with_bits(crypto_pk_t *env, int bits) return 0; } +/** A PEM callback that always reports a failure to get a password */ +static int +pem_no_password_cb(char *buf, int size, int rwflag, void *u) +{ + (void)buf; + (void)size; + (void)rwflag; + (void)u; + return 0; +} + /** Read a PEM-encoded private key from the <b>len</b>-byte string <b>s</b> * into <b>env</b>. Return 0 on success, -1 on failure. If len is -1, * the string is nul-terminated. */ -/* Used here, and used for testing. */ int crypto_pk_read_private_key_from_string(crypto_pk_t *env, const char *s, ssize_t len) @@ -615,7 +625,7 @@ crypto_pk_read_private_key_from_string(crypto_pk_t *env, if (env->key) RSA_free(env->key); - env->key = PEM_read_bio_RSAPrivateKey(b,NULL,NULL,NULL); + env->key = PEM_read_bio_RSAPrivateKey(b,NULL,pem_no_password_cb,NULL); BIO_free(b); @@ -747,7 +757,7 @@ crypto_pk_read_public_key_from_string(crypto_pk_t *env, const char *src, if (env->key) RSA_free(env->key); - env->key = PEM_read_bio_RSAPublicKey(b, NULL, NULL, NULL); + env->key = PEM_read_bio_RSAPublicKey(b, NULL, pem_no_password_cb, NULL); BIO_free(b); if (!env->key) { crypto_log_errors(LOG_WARN, "reading public key from string"); diff --git a/src/or/rendservice.c b/src/or/rendservice.c index d958de9df9..ba8891eade 100644 --- a/src/or/rendservice.c +++ b/src/or/rendservice.c @@ -1162,6 +1162,7 @@ rend_service_introduce(origin_circuit_t *circuit, const uint8_t *request, time_t now = time(NULL); time_t elapsed; int replay; + size_t keylen; /* Do some initial validation and logging before we parse the cell */ if (circuit->base_.purpose != CIRCUIT_PURPOSE_S_INTRO) { @@ -1245,9 +1246,10 @@ rend_service_introduce(origin_circuit_t *circuit, const uint8_t *request, } /* check for replay of PK-encrypted portion. */ + keylen = crypto_pk_keysize(intro_key); replay = replaycache_add_test_and_elapsed( intro_point->accepted_intro_rsa_parts, - parsed_req->ciphertext, parsed_req->ciphertext_len, + parsed_req->ciphertext, MIN(parsed_req->ciphertext_len, keylen), &elapsed); if (replay) { |