diff options
Diffstat (limited to 'src/common/tortls.c')
| -rw-r--r-- | src/common/tortls.c | 46 |
1 files changed, 45 insertions, 1 deletions
diff --git a/src/common/tortls.c b/src/common/tortls.c index ceb6147232..5f1930d884 100644 --- a/src/common/tortls.c +++ b/src/common/tortls.c @@ -89,6 +89,9 @@ ENABLE_GCC_WARNING(redundant-decls) #define SSL3_FLAGS_ALLOW_UNSAFE_LEGACY_RENEGOTIATION 0x0010 #endif +/** Set to true iff openssl bug 7712 has been detected. */ +static int openssl_bug_7712_is_present = 0; + /** Return values for tor_tls_classify_client_ciphers. * * @{ @@ -1701,6 +1704,13 @@ tor_tls_new(int sock, int isServer) } #endif /* defined(SSL_set_tlsext_host_name) */ +#ifdef SSL_CTRL_SET_MAX_PROTO_VERSION + if (openssl_bug_7712_is_present) { + /* We can't actually use TLS 1.3 until this bug is fixed. */ + SSL_set_max_proto_version(result->ssl, TLS1_2_VERSION); + } +#endif + if (!SSL_set_cipher_list(result->ssl, isServer ? SERVER_CIPHER_LIST : CLIENT_CIPHER_LIST)) { tls_log_errors(NULL, LOG_WARN, LD_NET, "setting ciphers"); @@ -2586,7 +2596,8 @@ tor_tls_get_tlssecrets,(tor_tls_t *tls, uint8_t *secrets_out)) * provided <b>context</b> (<b>context_len</b> bytes long) and * <b>label</b> (a NUL-terminated string), compute a 32-byte secret in * <b>secrets_out</b> that only the parties to this TLS session can - * compute. Return 0 on success and -1 on failure. + * compute. Return 0 on success; -1 on failure; and -2 on failure + * caused by OpenSSL bug 7712. */ MOCK_IMPL(int, tor_tls_export_key_material,(tor_tls_t *tls, uint8_t *secrets_out, @@ -2601,6 +2612,39 @@ tor_tls_export_key_material,(tor_tls_t *tls, uint8_t *secrets_out, secrets_out, DIGEST256_LEN, label, strlen(label), context, context_len, 1); + + if (r != 1) { + int severity = openssl_bug_7712_is_present ? LOG_WARN : LOG_DEBUG; + tls_log_errors(tls, severity, LD_NET, "exporting keying material"); + } + +#ifdef TLS1_3_VERSION + if (r != 1 && + strlen(label) > 12 && + SSL_version(tls->ssl) >= TLS1_3_VERSION) { + + if (! openssl_bug_7712_is_present) { + /* We might have run into OpenSSL issue 7712, which caused OpenSSL + * 1.1.1a to not handle long labels. Let's test to see if we have. + */ + r = SSL_export_keying_material(tls->ssl, secrets_out, DIGEST256_LEN, + "short", 5, context, context_len, 1); + if (r == 1) { + /* A short label succeeds, but a long label fails. This was openssl + * issue 7712. */ + openssl_bug_7712_is_present = 1; + log_warn(LD_GENERAL, "Detected OpenSSL bug 7712: disabling TLS 1.3 on " + "future connections. A fix is expected to appear in OpenSSL " + "1.1.1b."); + } + } + if (openssl_bug_7712_is_present) + return -2; + else + return -1; + } +#endif + return (r == 1) ? 0 : -1; } |