diff options
Diffstat (limited to 'lib/vtls/openssl.c')
| -rw-r--r-- | lib/vtls/openssl.c | 168 |
1 files changed, 168 insertions, 0 deletions
diff --git a/lib/vtls/openssl.c b/lib/vtls/openssl.c index c42143a85..a05c994fd 100644 --- a/lib/vtls/openssl.c +++ b/lib/vtls/openssl.c @@ -146,6 +146,20 @@ static unsigned long OpenSSL_version_num(void) #define OPENSSL_load_builtin_modules(x) #endif +/* + * Whether SSL_CTX_set_keylog_callback is available. + * OpenSSL: supported since 1.1.1 https://github.com/openssl/openssl/pull/2287 + * BoringSSL: supported since d28f59c27bac (committed 2015-11-19), the + * BORINGSSL_201512 macro from 2016-01-21 should be close enough. + * LibreSSL: unsupported in at least 2.5.1 (explicitly check for it since it + * lies and pretends to be OpenSSL 2.0.0). + */ +#if (OPENSSL_VERSION_NUMBER >= 0x10101000L && \ + !defined(LIBRESSL_VERSION_NUMBER)) || \ + defined(BORINGSSL_201512) +#define HAVE_KEYLOG_CALLBACK +#endif + #if defined(LIBRESSL_VERSION_NUMBER) #define OSSL_PACKAGE "LibreSSL" #elif defined(OPENSSL_IS_BORINGSSL) @@ -165,11 +179,23 @@ static unsigned long OpenSSL_version_num(void) "ALL:!EXPORT:!EXPORT40:!EXPORT56:!aNULL:!LOW:!RC4:@STRENGTH" #endif +#ifdef ENABLE_SSLKEYLOGFILE +typedef struct ssl_tap_state { + int master_key_length; + unsigned char master_key[SSL_MAX_MASTER_KEY_LENGTH]; + unsigned char client_random[SSL3_RANDOM_SIZE]; +} ssl_tap_state_t; +#endif /* ENABLE_SSLKEYLOGFILE */ + struct ssl_backend_data { /* these ones requires specific SSL-types */ SSL_CTX* ctx; SSL* handle; X509* server_cert; +#ifdef ENABLE_SSLKEYLOGFILE + /* tap_state holds the last seen master key if we're logging them */ + ssl_tap_state_t tap_state; +#endif }; #define BACKEND connssl->backend @@ -182,6 +208,112 @@ struct ssl_backend_data { */ #define RAND_LOAD_LENGTH 1024 +#ifdef ENABLE_SSLKEYLOGFILE +/* The fp for the open SSLKEYLOGFILE, or NULL if not open */ +static FILE *keylog_file_fp; + +#ifdef HAVE_KEYLOG_CALLBACK +static void ossl_keylog_callback(const SSL *ssl, const char *line) +{ + (void)ssl; + + /* Using fputs here instead of fprintf since libcurl's fprintf replacement + may not be thread-safe. */ + if(keylog_file_fp && line && *line) { + char stackbuf[256]; + char *buf; + size_t linelen = strlen(line); + + if(linelen <= sizeof(stackbuf) - 2) + buf = stackbuf; + else { + buf = malloc(linelen + 2); + if(!buf) + return; + } + strncpy(buf, line, linelen); + buf[linelen] = '\n'; + buf[linelen + 1] = '\0'; + + fputs(buf, keylog_file_fp); + if(buf != stackbuf) + free(buf); + } +} +#else +#define KEYLOG_PREFIX "CLIENT_RANDOM " +#define KEYLOG_PREFIX_LEN (sizeof(KEYLOG_PREFIX) - 1) +/* + * tap_ssl_key is called by libcurl to make the CLIENT_RANDOMs if the OpenSSL + * being used doesn't have native support for doing that. + */ +static void tap_ssl_key(const SSL *ssl, ssl_tap_state_t *state) +{ + const char *hex = "0123456789ABCDEF"; + int pos, i; + char line[KEYLOG_PREFIX_LEN + 2 * SSL3_RANDOM_SIZE + 1 + + 2 * SSL_MAX_MASTER_KEY_LENGTH + 1 + 1]; + const SSL_SESSION *session = SSL_get_session(ssl); + unsigned char client_random[SSL3_RANDOM_SIZE]; + unsigned char master_key[SSL_MAX_MASTER_KEY_LENGTH]; + int master_key_length = 0; + + if(!session || !keylog_file_fp) + return; + +#if OPENSSL_VERSION_NUMBER >= 0x10100000L + /* ssl->s3 is not checked in openssl 1.1.0-pre6, but let's assume that + * we have a valid SSL context if we have a non-NULL session. */ + SSL_get_client_random(ssl, client_random, SSL3_RANDOM_SIZE); + master_key_length = + SSL_SESSION_get_master_key(session, master_key, SSL_MAX_MASTER_KEY_LENGTH); +#else + if(ssl->s3 && session->master_key_length > 0) { + master_key_length = session->master_key_length; + memcpy(master_key, session->master_key, session->master_key_length); + memcpy(client_random, ssl->s3->client_random, SSL3_RANDOM_SIZE); + } +#endif + + if(master_key_length <= 0) + return; + + /* Skip writing keys if there is no key or it did not change. */ + if(state->master_key_length == master_key_length && + !memcmp(state->master_key, master_key, master_key_length) && + !memcmp(state->client_random, client_random, SSL3_RANDOM_SIZE)) { + return; + } + + state->master_key_length = master_key_length; + memcpy(state->master_key, master_key, master_key_length); + memcpy(state->client_random, client_random, SSL3_RANDOM_SIZE); + + memcpy(line, KEYLOG_PREFIX, KEYLOG_PREFIX_LEN); + pos = KEYLOG_PREFIX_LEN; + + /* Client Random for SSLv3/TLS */ + for(i = 0; i < SSL3_RANDOM_SIZE; i++) { + line[pos++] = hex[client_random[i] >> 4]; + line[pos++] = hex[client_random[i] & 0xF]; + } + line[pos++] = ' '; + + /* Master Secret (size is at most SSL_MAX_MASTER_KEY_LENGTH) */ + for(i = 0; i < master_key_length; i++) { + line[pos++] = hex[master_key[i] >> 4]; + line[pos++] = hex[master_key[i] & 0xF]; + } + line[pos++] = '\n'; + line[pos] = '\0'; + + /* Using fputs here instead of fprintf since libcurl's fprintf replacement + may not be thread-safe. */ + fputs(line, keylog_file_fp); +} +#endif /* !HAVE_KEYLOG_CALLBACK */ +#endif /* ENABLE_SSLKEYLOGFILE */ + static const char *SSL_ERROR_to_str(int err) { switch(err) { @@ -756,6 +888,10 @@ static int x509_name_oneline(X509_NAME *a, char *buf, size_t size) */ static int Curl_ossl_init(void) { +#ifdef ENABLE_SSLKEYLOGFILE + const char *keylog_file_name; +#endif + OPENSSL_load_builtin_modules(); #ifdef HAVE_ENGINE_LOAD_BUILTIN_ENGINES @@ -792,6 +928,19 @@ static int Curl_ossl_init(void) OpenSSL_add_all_algorithms(); #endif +#ifdef ENABLE_SSLKEYLOGFILE + keylog_file_name = curl_getenv("SSLKEYLOGFILE"); + if(keylog_file_name && !keylog_file_fp) { + keylog_file_fp = fopen(keylog_file_name, FOPEN_APPENDTEXT); + if(keylog_file_fp) { + if(setvbuf(keylog_file_fp, NULL, _IOLBF, 4096)) { + fclose(keylog_file_fp); + keylog_file_fp = NULL; + } + } + } +#endif + return 1; } @@ -828,6 +977,13 @@ static void Curl_ossl_cleanup(void) SSL_COMP_free_compression_methods(); #endif #endif + +#ifdef ENABLE_SSLKEYLOGFILE + if(keylog_file_fp) { + fclose(keylog_file_fp); + keylog_file_fp = NULL; + } +#endif } /* @@ -2231,6 +2387,13 @@ static CURLcode ossl_connect_step1(struct connectdata *conn, int sockindex) SSL_CTX_set_verify(BACKEND->ctx, verifypeer ? SSL_VERIFY_PEER : SSL_VERIFY_NONE, NULL); + /* Enable logging of secrets to the file specified in env SSLKEYLOGFILE. */ +#if defined(ENABLE_SSLKEYLOGFILE) && defined(HAVE_KEYLOG_CALLBACK) + if(keylog_file) { + SSL_CTX_set_keylog_callback(connssl->ctx, ossl_keylog_callback); + } +#endif + /* give application a chance to interfere with SSL set up. */ if(data->set.ssl.fsslctx) { result = (*data->set.ssl.fsslctx)(data, BACKEND->ctx, @@ -2325,6 +2488,11 @@ static CURLcode ossl_connect_step2(struct connectdata *conn, int sockindex) ERR_clear_error(); err = SSL_connect(BACKEND->handle); + /* If keylogging is enabled but the keylog callback is not supported then log + secrets here, immediately after SSL_connect by using tap_ssl_key. */ +#if defined(ENABLE_SSLKEYLOGFILE) && !defined(HAVE_KEYLOG_CALLBACK) + tap_ssl_key(BACKEND->handle, &BACKEND->tap_state); +#endif /* 1 is fine 0 is "not successful but was shut down controlled" |