/* Copyright (c) 2003, Roger Dingledine. * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson. * Copyright (c) 2007-2018, The Tor Project, Inc. */ /* See LICENSE for licensing information */ /** * \file tortls.c * \brief Wrapper functions to present a consistent interface to * TLS, SSL, and X.509 functions from OpenSSL. **/ /* (Unlike other tor functions, these * are prefixed with tor_ in order to avoid conflicting with OpenSSL * functions and variables.) */ #include "orconfig.h" #define TORTLS_PRIVATE #define TORTLS_OPENSSL_PRIVATE #define TOR_X509_PRIVATE #ifdef _WIN32 /* We need to include these here, or else the dtls1.h header will include * and mess things up, in at least some openssl versions. */ #include #include #endif #include "lib/crypt_ops/crypto_cipher.h" #include "lib/crypt_ops/crypto_rand.h" #include "lib/crypt_ops/crypto_dh.h" #include "lib/crypt_ops/crypto_util.h" #include "lib/crypt_ops/compat_openssl.h" #include "lib/tls/x509.h" #include "lib/tls/x509_internal.h" /* Some versions of OpenSSL declare SSL_get_selected_srtp_profile twice in * srtp.h. Suppress the GCC warning so we can build with -Wredundant-decl. */ DISABLE_GCC_WARNING(redundant-decls) #include #ifdef OPENSSL_NO_EC #error "We require OpenSSL with ECC support" #endif #include #include #include #include #include #include #include #include ENABLE_GCC_WARNING(redundant-decls) #include "lib/tls/tortls.h" #include "lib/tls/tortls_st.h" #include "lib/tls/tortls_internal.h" #include "lib/log/log.h" #include "lib/log/util_bug.h" #include "lib/container/smartlist.h" #include "lib/string/compat_string.h" #include "lib/string/printf.h" #include "lib/net/socket.h" #include "lib/intmath/cmp.h" #include "lib/ctime/di_ops.h" #include "lib/encoding/time_fmt.h" #include #include #include "lib/arch/bytes.h" /* Copied from or.h */ #define LEGAL_NICKNAME_CHARACTERS \ "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789" #define ADDR(tls) (((tls) && (tls)->address) ? tls->address : "peer") #if OPENSSL_VERSION_NUMBER < OPENSSL_V(1,0,0,'f') /* This is a version of OpenSSL before 1.0.0f. It does not have * the CVE-2011-4576 fix, and as such it can't use RELEASE_BUFFERS and * SSL3 safely at the same time. */ #define DISABLE_SSL3_HANDSHAKE #endif /* OPENSSL_VERSION_NUMBER < OPENSSL_V(1,0,0,'f') */ /* We redefine these so that we can run correctly even if the vendor gives us * a version of OpenSSL that does not match its header files. (Apple: I am * looking at you.) */ #ifndef SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION #define SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION 0x00040000L #endif #ifndef SSL3_FLAGS_ALLOW_UNSAFE_LEGACY_RENEGOTIATION #define SSL3_FLAGS_ALLOW_UNSAFE_LEGACY_RENEGOTIATION 0x0010 #endif /** Return values for tor_tls_classify_client_ciphers. * * @{ */ /** An error occurred when examining the client ciphers */ #define CIPHERS_ERR -1 /** The client cipher list indicates that a v1 handshake was in use. */ #define CIPHERS_V1 1 /** The client cipher list indicates that the client is using the v2 or the * v3 handshake, but that it is (probably!) lying about what ciphers it * supports */ #define CIPHERS_V2 2 /** The client cipher list indicates that the client is using the v2 or the * v3 handshake, and that it is telling the truth about what ciphers it * supports */ #define CIPHERS_UNRESTRICTED 3 /** @} */ /** The ex_data index in which we store a pointer to an SSL object's * corresponding tor_tls_t object. */ STATIC int tor_tls_object_ex_data_index = -1; /** Helper: Allocate tor_tls_object_ex_data_index. */ void tor_tls_allocate_tor_tls_object_ex_data_index(void) { if (tor_tls_object_ex_data_index == -1) { tor_tls_object_ex_data_index = SSL_get_ex_new_index(0, NULL, NULL, NULL, NULL); tor_assert(tor_tls_object_ex_data_index != -1); } } /** Helper: given a SSL* pointer, return the tor_tls_t object using that * pointer. */ tor_tls_t * tor_tls_get_by_ssl(const SSL *ssl) { tor_tls_t *result = SSL_get_ex_data(ssl, tor_tls_object_ex_data_index); if (result) tor_assert(result->magic == TOR_TLS_MAGIC); return result; } /** True iff tor_tls_init() has been called. */ static int tls_library_is_initialized = 0; /* Module-internal error codes. */ #define TOR_TLS_SYSCALL_ (MIN_TOR_TLS_ERROR_VAL_ - 2) #define TOR_TLS_ZERORETURN_ (MIN_TOR_TLS_ERROR_VAL_ - 1) /** Write a description of the current state of tls into the * sz-byte buffer at buf. */ void tor_tls_get_state_description(tor_tls_t *tls, char *buf, size_t sz) { const char *ssl_state; const char *tortls_state; if (PREDICT_UNLIKELY(!tls || !tls->ssl)) { strlcpy(buf, "(No SSL object)", sz); return; } ssl_state = SSL_state_string_long(tls->ssl); switch (tls->state) { #define CASE(st) case TOR_TLS_ST_##st: tortls_state = " in "#st ; break CASE(HANDSHAKE); CASE(OPEN); CASE(GOTCLOSE); CASE(SENTCLOSE); CASE(CLOSED); CASE(RENEGOTIATE); #undef CASE case TOR_TLS_ST_BUFFEREVENT: tortls_state = ""; break; default: tortls_state = " in unknown TLS state"; break; } tor_snprintf(buf, sz, "%s%s", ssl_state, tortls_state); } /** Log a single error err as returned by ERR_get_error(), which was * received while performing an operation doing on tls. Log * the message at severity, in log domain domain. */ void tor_tls_log_one_error(tor_tls_t *tls, unsigned long err, int severity, int domain, const char *doing) { const char *state = NULL, *addr; const char *msg, *lib, *func; state = (tls && tls->ssl)?SSL_state_string_long(tls->ssl):"---"; addr = tls ? tls->address : NULL; /* Some errors are known-benign, meaning they are the fault of the other * side of the connection. The caller doesn't know this, so override the * priority for those cases. */ switch (ERR_GET_REASON(err)) { case SSL_R_HTTP_REQUEST: case SSL_R_HTTPS_PROXY_REQUEST: case SSL_R_RECORD_LENGTH_MISMATCH: #ifndef OPENSSL_1_1_API case SSL_R_RECORD_TOO_LARGE: #endif case SSL_R_UNKNOWN_PROTOCOL: case SSL_R_UNSUPPORTED_PROTOCOL: severity = LOG_INFO; break; default: break; } msg = (const char*)ERR_reason_error_string(err); lib = (const char*)ERR_lib_error_string(err); func = (const char*)ERR_func_error_string(err); if (!msg) msg = "(null)"; if (!lib) lib = "(null)"; if (!func) func = "(null)"; if (doing) { tor_log(severity, domain, "TLS error while %s%s%s: %s (in %s:%s:%s)", doing, addr?" with ":"", addr?addr:"", msg, lib, func, state); } else { tor_log(severity, domain, "TLS error%s%s: %s (in %s:%s:%s)", addr?" with ":"", addr?addr:"", msg, lib, func, state); } } /** Log all pending tls errors at level severity in log domain * domain. Use doing to describe our current activities. */ void tls_log_errors(tor_tls_t *tls, int severity, int domain, const char *doing) { unsigned long err; while ((err = ERR_get_error()) != 0) { tor_tls_log_one_error(tls, err, severity, domain, doing); } } #define CATCH_SYSCALL 1 #define CATCH_ZERO 2 /** Given a TLS object and the result of an SSL_* call, use * SSL_get_error to determine whether an error has occurred, and if so * which one. Return one of TOR_TLS_{DONE|WANTREAD|WANTWRITE|ERROR}. * If extra&CATCH_SYSCALL is true, return TOR_TLS_SYSCALL_ instead of * reporting syscall errors. If extra&CATCH_ZERO is true, return * TOR_TLS_ZERORETURN_ instead of reporting zero-return errors. * * If an error has occurred, log it at level severity and describe the * current action as doing. */ int tor_tls_get_error(tor_tls_t *tls, int r, int extra, const char *doing, int severity, int domain) { int err = SSL_get_error(tls->ssl, r); int tor_error = TOR_TLS_ERROR_MISC; switch (err) { case SSL_ERROR_NONE: return TOR_TLS_DONE; case SSL_ERROR_WANT_READ: return TOR_TLS_WANTREAD; case SSL_ERROR_WANT_WRITE: return TOR_TLS_WANTWRITE; case SSL_ERROR_SYSCALL: if (extra&CATCH_SYSCALL) return TOR_TLS_SYSCALL_; if (r == 0) { tor_log(severity, LD_NET, "TLS error: unexpected close while %s (%s)", doing, SSL_state_string_long(tls->ssl)); tor_error = TOR_TLS_ERROR_IO; } else { int e = tor_socket_errno(tls->socket); tor_log(severity, LD_NET, "TLS error: (errno=%d: %s; state=%s)", doing, e, tor_socket_strerror(e), SSL_state_string_long(tls->ssl)); tor_error = tor_errno_to_tls_error(e); } tls_log_errors(tls, severity, domain, doing); return tor_error; case SSL_ERROR_ZERO_RETURN: if (extra&CATCH_ZERO) return TOR_TLS_ZERORETURN_; tor_log(severity, LD_NET, "TLS connection closed while %s in state %s", doing, SSL_state_string_long(tls->ssl)); tls_log_errors(tls, severity, domain, doing); return TOR_TLS_CLOSE; default: tls_log_errors(tls, severity, domain, doing); return TOR_TLS_ERROR_MISC; } } /** Initialize OpenSSL, unless it has already been initialized. */ void tor_tls_init(void) { check_no_tls_errors(); if (!tls_library_is_initialized) { #ifdef OPENSSL_1_1_API OPENSSL_init_ssl(OPENSSL_INIT_LOAD_SSL_STRINGS, NULL); #else SSL_library_init(); SSL_load_error_strings(); #endif #if (SIZEOF_VOID_P >= 8 && \ OPENSSL_VERSION_NUMBER >= OPENSSL_V_SERIES(1,0,1)) long version = OpenSSL_version_num(); /* LCOV_EXCL_START : we can't test these lines on the same machine */ if (version >= OPENSSL_V_SERIES(1,0,1)) { /* Warn if we could *almost* be running with much faster ECDH. If we're built for a 64-bit target, using OpenSSL 1.0.1, but we don't have one of the built-in __uint128-based speedups, we are just one build operation away from an accelerated handshake. (We could be looking at OPENSSL_NO_EC_NISTP_64_GCC_128 instead of doing this test, but that gives compile-time options, not runtime behavior.) */ EC_KEY *key = EC_KEY_new_by_curve_name(NID_X9_62_prime256v1); const EC_GROUP *g = key ? EC_KEY_get0_group(key) : NULL; const EC_METHOD *m = g ? EC_GROUP_method_of(g) : NULL; const int warn = (m == EC_GFp_simple_method() || m == EC_GFp_mont_method() || m == EC_GFp_nist_method()); EC_KEY_free(key); if (warn) log_notice(LD_GENERAL, "We were built to run on a 64-bit CPU, with " "OpenSSL 1.0.1 or later, but with a version of OpenSSL " "that apparently lacks accelerated support for the NIST " "P-224 and P-256 groups. Building openssl with such " "support (using the enable-ec_nistp_64_gcc_128 option " "when configuring it) would make ECDH much faster."); } /* LCOV_EXCL_STOP */ #endif /* (SIZEOF_VOID_P >= 8 && ... */ tor_tls_allocate_tor_tls_object_ex_data_index(); tls_library_is_initialized = 1; } } /** We need to give OpenSSL a callback to verify certificates. This is * it: We always accept peer certs and complete the handshake. We * don't validate them until later. */ int always_accept_verify_cb(int preverify_ok, X509_STORE_CTX *x509_ctx) { (void) preverify_ok; (void) x509_ctx; return 1; } /** List of ciphers that servers should select from when the client might be * claiming extra unsupported ciphers in order to avoid fingerprinting. */ static const char SERVER_CIPHER_LIST[] = #ifdef TLS1_3_TXT_AES_128_GCM_SHA256 /* This one can never actually get selected, since if the client lists it, * we will assume that the client is honest, and not use this list. * Nonetheless we list it if it's available, so that the server doesn't * conclude that it has no valid ciphers if it's running with TLS1.3. */ TLS1_3_TXT_AES_128_GCM_SHA256 ":" #endif TLS1_TXT_DHE_RSA_WITH_AES_256_SHA ":" TLS1_TXT_DHE_RSA_WITH_AES_128_SHA; /** List of ciphers that servers should select from when we actually have * our choice of what cipher to use. */ static const char UNRESTRICTED_SERVER_CIPHER_LIST[] = /* Here are the TLS 1.3 ciphers we like, in the order we prefer. */ #ifdef TLS1_3_TXT_AES_256_GCM_SHA384 TLS1_3_TXT_AES_256_GCM_SHA384 ":" #endif #ifdef TLS1_3_TXT_CHACHA20_POLY1305_SHA256 TLS1_3_TXT_CHACHA20_POLY1305_SHA256 ":" #endif #ifdef TLS1_3_TXT_AES_128_GCM_SHA256 TLS1_3_TXT_AES_128_GCM_SHA256 ":" #endif #ifdef TLS1_3_TXT_AES_128_CCM_SHA256 TLS1_3_TXT_AES_128_CCM_SHA256 ":" #endif /* This list is autogenerated with the gen_server_ciphers.py script; * don't hand-edit it. */ #ifdef TLS1_TXT_ECDHE_RSA_WITH_AES_256_GCM_SHA384 TLS1_TXT_ECDHE_RSA_WITH_AES_256_GCM_SHA384 ":" #endif #ifdef TLS1_TXT_ECDHE_RSA_WITH_AES_128_GCM_SHA256 TLS1_TXT_ECDHE_RSA_WITH_AES_128_GCM_SHA256 ":" #endif #ifdef TLS1_TXT_ECDHE_RSA_WITH_AES_256_SHA384 TLS1_TXT_ECDHE_RSA_WITH_AES_256_SHA384 ":" #endif #ifdef TLS1_TXT_ECDHE_RSA_WITH_AES_128_SHA256 TLS1_TXT_ECDHE_RSA_WITH_AES_128_SHA256 ":" #endif #ifdef TLS1_TXT_ECDHE_RSA_WITH_AES_256_CBC_SHA TLS1_TXT_ECDHE_RSA_WITH_AES_256_CBC_SHA ":" #endif #ifdef TLS1_TXT_ECDHE_RSA_WITH_AES_128_CBC_SHA TLS1_TXT_ECDHE_RSA_WITH_AES_128_CBC_SHA ":" #endif #ifdef TLS1_TXT_DHE_RSA_WITH_AES_256_GCM_SHA384 TLS1_TXT_DHE_RSA_WITH_AES_256_GCM_SHA384 ":" #endif #ifdef TLS1_TXT_DHE_RSA_WITH_AES_128_GCM_SHA256 TLS1_TXT_DHE_RSA_WITH_AES_128_GCM_SHA256 ":" #endif #ifdef TLS1_TXT_DHE_RSA_WITH_AES_256_CCM TLS1_TXT_DHE_RSA_WITH_AES_256_CCM ":" #endif #ifdef TLS1_TXT_DHE_RSA_WITH_AES_128_CCM TLS1_TXT_DHE_RSA_WITH_AES_128_CCM ":" #endif #ifdef TLS1_TXT_DHE_RSA_WITH_AES_256_SHA256 TLS1_TXT_DHE_RSA_WITH_AES_256_SHA256 ":" #endif #ifdef TLS1_TXT_DHE_RSA_WITH_AES_128_SHA256 TLS1_TXT_DHE_RSA_WITH_AES_128_SHA256 ":" #endif /* Required */ TLS1_TXT_DHE_RSA_WITH_AES_256_SHA ":" /* Required */ TLS1_TXT_DHE_RSA_WITH_AES_128_SHA ":" #ifdef TLS1_TXT_ECDHE_RSA_WITH_CHACHA20_POLY1305 TLS1_TXT_ECDHE_RSA_WITH_CHACHA20_POLY1305 ":" #endif #ifdef TLS1_TXT_DHE_RSA_WITH_CHACHA20_POLY1305 TLS1_TXT_DHE_RSA_WITH_CHACHA20_POLY1305 #endif ; /* Note: to set up your own private testing network with link crypto * disabled, set your Tors' cipher list to * (SSL3_TXT_RSA_NULL_SHA). If you do this, you won't be able to communicate * with any of the "real" Tors, though. */ #define CIPHER(id, name) name ":" #define XCIPHER(id, name) /** List of ciphers that clients should advertise, omitting items that * our OpenSSL doesn't know about. */ static const char CLIENT_CIPHER_LIST[] = #include "ciphers.inc" /* Tell it not to use SSLv2 ciphers, so that it can select an SSLv3 version * of any cipher we say. */ "!SSLv2" ; #undef CIPHER #undef XCIPHER /** Return true iff the other side of tls has authenticated to us, and * the key certified in cert is the same as the key they used to do it. */ MOCK_IMPL(int, tor_tls_cert_matches_key,(const tor_tls_t *tls, const tor_x509_cert_t *cert)) { tor_x509_cert_t *peer = tor_tls_get_peer_cert((tor_tls_t *)tls); if (!peer) return 0; X509 *peercert = peer->cert; EVP_PKEY *link_key = NULL, *cert_key = NULL; int result; link_key = X509_get_pubkey(peercert); cert_key = X509_get_pubkey(cert->cert); result = link_key && cert_key && EVP_PKEY_cmp(cert_key, link_key) == 1; tor_x509_cert_free(peer); if (link_key) EVP_PKEY_free(link_key); if (cert_key) EVP_PKEY_free(cert_key); return result; } void tor_tls_context_impl_free_(struct ssl_ctx_st *ctx) { if (!ctx) return; SSL_CTX_free(ctx); } /** The group we should use for ecdhe when none was selected. */ #define NID_tor_default_ecdhe_group NID_X9_62_prime256v1 /** Create a new TLS context for use with Tor TLS handshakes. * identity should be set to the identity key used to sign the * certificate. */ tor_tls_context_t * tor_tls_context_new(crypto_pk_t *identity, unsigned int key_lifetime, unsigned flags, int is_client) { EVP_PKEY *pkey = NULL; tor_tls_context_t *result = NULL; tor_tls_init(); result = tor_malloc_zero(sizeof(tor_tls_context_t)); result->refcnt = 1; if (! is_client) { if (tor_tls_context_init_certificates(result, identity, key_lifetime, flags) < 0) { goto error; } } #if 0 /* Tell OpenSSL to only use TLS1. This may have subtly different results * from SSLv23_method() with SSLv2 and SSLv3 disabled, so we need to do some * investigation before we consider adjusting it. It should be compatible * with existing Tors. */ if (!(result->ctx = SSL_CTX_new(TLSv1_method()))) goto error; #endif /* 0 */ /* Tell OpenSSL to use TLS 1.0 or later but not SSL2 or SSL3. */ #ifdef HAVE_TLS_METHOD if (!(result->ctx = SSL_CTX_new(TLS_method()))) goto error; #else if (!(result->ctx = SSL_CTX_new(SSLv23_method()))) goto error; #endif /* defined(HAVE_TLS_METHOD) */ #ifdef HAVE_SSL_CTX_SET_SECURITY_LEVEL /* Level 1 re-enables RSA1024 and DH1024 for compatibility with old tors */ SSL_CTX_set_security_level(result->ctx, 1); #endif SSL_CTX_set_options(result->ctx, SSL_OP_NO_SSLv2); SSL_CTX_set_options(result->ctx, SSL_OP_NO_SSLv3); /* Prefer the server's ordering of ciphers: the client's ordering has * historically been chosen for fingerprinting resistance. */ SSL_CTX_set_options(result->ctx, SSL_OP_CIPHER_SERVER_PREFERENCE); /* Disable TLS tickets if they're supported. We never want to use them; * using them can make our perfect forward secrecy a little worse, *and* * create an opportunity to fingerprint us (since it's unusual to use them * with TLS sessions turned off). * * In 0.2.4, clients advertise support for them though, to avoid a TLS * distinguishability vector. This can give us worse PFS, though, if we * get a server that doesn't set SSL_OP_NO_TICKET. With luck, there will * be few such servers by the time 0.2.4 is more stable. */ #ifdef SSL_OP_NO_TICKET if (! is_client) { SSL_CTX_set_options(result->ctx, SSL_OP_NO_TICKET); } #endif SSL_CTX_set_options(result->ctx, SSL_OP_SINGLE_DH_USE); SSL_CTX_set_options(result->ctx, SSL_OP_SINGLE_ECDH_USE); #ifdef SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION SSL_CTX_set_options(result->ctx, SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION); #endif /* Yes, we know what we are doing here. No, we do not treat a renegotiation * as authenticating any earlier-received data. */ { SSL_CTX_set_options(result->ctx, SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION); } /* Don't actually allow compression; it uses RAM and time, it makes TLS * vulnerable to CRIME-style attacks, and most of the data we transmit over * TLS is encrypted (and therefore uncompressible) anyway. */ #ifdef SSL_OP_NO_COMPRESSION SSL_CTX_set_options(result->ctx, SSL_OP_NO_COMPRESSION); #endif #if OPENSSL_VERSION_NUMBER < OPENSSL_V_SERIES(1,1,0) #ifndef OPENSSL_NO_COMP if (result->ctx->comp_methods) result->ctx->comp_methods = NULL; #endif #endif /* OPENSSL_VERSION_NUMBER < OPENSSL_V_SERIES(1,1,0) */ #ifdef SSL_MODE_RELEASE_BUFFERS SSL_CTX_set_mode(result->ctx, SSL_MODE_RELEASE_BUFFERS); #endif if (! is_client) { if (result->my_link_cert && !SSL_CTX_use_certificate(result->ctx, result->my_link_cert->cert)) { goto error; } if (result->my_id_cert) { X509_STORE *s = SSL_CTX_get_cert_store(result->ctx); tor_assert(s); X509_STORE_add_cert(s, result->my_id_cert->cert); } } SSL_CTX_set_session_cache_mode(result->ctx, SSL_SESS_CACHE_OFF); if (!is_client) { tor_assert(result->link_key); if (!(pkey = crypto_pk_get_openssl_evp_pkey_(result->link_key,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; } { DH *dh = crypto_dh_new_openssl_tls(); tor_assert(dh); SSL_CTX_set_tmp_dh(result->ctx, dh); DH_free(dh); } /* We check for this function in two ways, since it might be either a symbol * or a macro. */ #if defined(SSL_CTX_set1_groups_list) || defined(HAVE_SSL_CTX_SET1_GROUPS_LIST) { const char *list; if (flags & TOR_TLS_CTX_USE_ECDHE_P224) list = "P-224:P-256"; else if (flags & TOR_TLS_CTX_USE_ECDHE_P256) list = "P-256:P-224"; else list = "P-256:P-224"; int r = (int) SSL_CTX_set1_groups_list(result->ctx, list); if (r < 0) goto error; } #else if (! is_client) { int nid; EC_KEY *ec_key; if (flags & TOR_TLS_CTX_USE_ECDHE_P224) nid = NID_secp224r1; else if (flags & TOR_TLS_CTX_USE_ECDHE_P256) nid = NID_X9_62_prime256v1; else nid = NID_tor_default_ecdhe_group; /* Use P-256 for ECDHE. */ ec_key = EC_KEY_new_by_curve_name(nid); if (ec_key != NULL) /*XXXX Handle errors? */ SSL_CTX_set_tmp_ecdh(result->ctx, ec_key); EC_KEY_free(ec_key); } #endif SSL_CTX_set_verify(result->ctx, SSL_VERIFY_PEER, always_accept_verify_cb); /* let us realloc bufs that we're writing from */ SSL_CTX_set_mode(result->ctx, SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER); return result; error: tls_log_errors(NULL, LOG_WARN, LD_NET, "creating TLS context"); if (pkey) EVP_PKEY_free(pkey); tor_tls_context_decref(result); return NULL; } /** Invoked when a TLS state changes: log the change at severity 'debug' */ void tor_tls_debug_state_callback(const SSL *ssl, int type, int val) { /* LCOV_EXCL_START since this depends on whether debug is captured or not */ log_debug(LD_HANDSHAKE, "SSL %p is now in state %s [type=%d,val=%d].", ssl, SSL_state_string_long(ssl), type, val); /* LCOV_EXCL_STOP */ } /* Return the name of the negotiated ciphersuite in use on tls */ const char * tor_tls_get_ciphersuite_name(tor_tls_t *tls) { return SSL_get_cipher(tls->ssl); } /* Here's the old V2 cipher list we sent from 0.2.1.1-alpha up to * 0.2.3.17-beta. If a client is using this list, we can't believe the ciphers * that it claims to support. We'll prune this list to remove the ciphers * *we* don't recognize. */ STATIC uint16_t v2_cipher_list[] = { 0xc00a, /* TLS1_TXT_ECDHE_ECDSA_WITH_AES_256_CBC_SHA */ 0xc014, /* TLS1_TXT_ECDHE_RSA_WITH_AES_256_CBC_SHA */ 0x0039, /* TLS1_TXT_DHE_RSA_WITH_AES_256_SHA */ 0x0038, /* TLS1_TXT_DHE_DSS_WITH_AES_256_SHA */ 0xc00f, /* TLS1_TXT_ECDH_RSA_WITH_AES_256_CBC_SHA */ 0xc005, /* TLS1_TXT_ECDH_ECDSA_WITH_AES_256_CBC_SHA */ 0x0035, /* TLS1_TXT_RSA_WITH_AES_256_SHA */ 0xc007, /* TLS1_TXT_ECDHE_ECDSA_WITH_RC4_128_SHA */ 0xc009, /* TLS1_TXT_ECDHE_ECDSA_WITH_AES_128_CBC_SHA */ 0xc011, /* TLS1_TXT_ECDHE_RSA_WITH_RC4_128_SHA */ 0xc013, /* TLS1_TXT_ECDHE_RSA_WITH_AES_128_CBC_SHA */ 0x0033, /* TLS1_TXT_DHE_RSA_WITH_AES_128_SHA */ 0x0032, /* TLS1_TXT_DHE_DSS_WITH_AES_128_SHA */ 0xc00c, /* TLS1_TXT_ECDH_RSA_WITH_RC4_128_SHA */ 0xc00e, /* TLS1_TXT_ECDH_RSA_WITH_AES_128_CBC_SHA */ 0xc002, /* TLS1_TXT_ECDH_ECDSA_WITH_RC4_128_SHA */ 0xc004, /* TLS1_TXT_ECDH_ECDSA_WITH_AES_128_CBC_SHA */ 0x0004, /* SSL3_TXT_RSA_RC4_128_MD5 */ 0x0005, /* SSL3_TXT_RSA_RC4_128_SHA */ 0x002f, /* TLS1_TXT_RSA_WITH_AES_128_SHA */ 0xc008, /* TLS1_TXT_ECDHE_ECDSA_WITH_DES_192_CBC3_SHA */ 0xc012, /* TLS1_TXT_ECDHE_RSA_WITH_DES_192_CBC3_SHA */ 0x0016, /* SSL3_TXT_EDH_RSA_DES_192_CBC3_SHA */ 0x0013, /* SSL3_TXT_EDH_DSS_DES_192_CBC3_SHA */ 0xc00d, /* TLS1_TXT_ECDH_RSA_WITH_DES_192_CBC3_SHA */ 0xc003, /* TLS1_TXT_ECDH_ECDSA_WITH_DES_192_CBC3_SHA */ 0xfeff, /* SSL3_TXT_RSA_FIPS_WITH_3DES_EDE_CBC_SHA */ 0x000a, /* SSL3_TXT_RSA_DES_192_CBC3_SHA */ 0 }; /** Have we removed the unrecognized ciphers from v2_cipher_list yet? */ static int v2_cipher_list_pruned = 0; /** Return 0 if m does not support the cipher with ID cipher; * return 1 if it does support it, or if we have no way to tell. */ int find_cipher_by_id(const SSL *ssl, const SSL_METHOD *m, uint16_t cipher) { const SSL_CIPHER *c; #ifdef HAVE_SSL_CIPHER_FIND (void) m; { unsigned char cipherid[3]; tor_assert(ssl); set_uint16(cipherid, tor_htons(cipher)); cipherid[2] = 0; /* If ssl23_get_cipher_by_char finds no cipher starting * with a two-byte 'cipherid', it may look for a v2 * cipher with the appropriate 3 bytes. */ c = SSL_CIPHER_find((SSL*)ssl, cipherid); if (c) tor_assert((SSL_CIPHER_get_id(c) & 0xffff) == cipher); return c != NULL; } #else /* !(defined(HAVE_SSL_CIPHER_FIND)) */ # if defined(HAVE_STRUCT_SSL_METHOD_ST_GET_CIPHER_BY_CHAR) if (m && m->get_cipher_by_char) { unsigned char cipherid[3]; set_uint16(cipherid, tor_htons(cipher)); cipherid[2] = 0; /* If ssl23_get_cipher_by_char finds no cipher starting * with a two-byte 'cipherid', it may look for a v2 * cipher with the appropriate 3 bytes. */ c = m->get_cipher_by_char(cipherid); if (c) tor_assert((c->id & 0xffff) == cipher); return c != NULL; } #endif /* defined(HAVE_STRUCT_SSL_METHOD_ST_GET_CIPHER_BY_CHAR) */ # ifndef OPENSSL_1_1_API if (m && m->get_cipher && m->num_ciphers) { /* It would seem that some of the "let's-clean-up-openssl" forks have * removed the get_cipher_by_char function. Okay, so now you get a * quadratic search. */ int i; for (i = 0; i < m->num_ciphers(); ++i) { c = m->get_cipher(i); if (c && (c->id & 0xffff) == cipher) { return 1; } } return 0; } #endif /* !defined(OPENSSL_1_1_API) */ (void) ssl; (void) m; (void) cipher; return 1; /* No way to search */ #endif /* defined(HAVE_SSL_CIPHER_FIND) */ } /** Remove from v2_cipher_list every cipher that we don't support, so that * comparing v2_cipher_list to a client's cipher list will give a sensible * result. */ static void prune_v2_cipher_list(const SSL *ssl) { uint16_t *inp, *outp; #ifdef HAVE_TLS_METHOD const SSL_METHOD *m = TLS_method(); #else const SSL_METHOD *m = SSLv23_method(); #endif inp = outp = v2_cipher_list; while (*inp) { if (find_cipher_by_id(ssl, m, *inp)) { *outp++ = *inp++; } else { inp++; } } *outp = 0; v2_cipher_list_pruned = 1; } /** Examine the client cipher list in ssl, and determine what kind of * client it is. Return one of CIPHERS_ERR, CIPHERS_V1, CIPHERS_V2, * CIPHERS_UNRESTRICTED. **/ int tor_tls_classify_client_ciphers(const SSL *ssl, STACK_OF(SSL_CIPHER) *peer_ciphers) { int i, res; tor_tls_t *tor_tls; if (PREDICT_UNLIKELY(!v2_cipher_list_pruned)) prune_v2_cipher_list(ssl); tor_tls = tor_tls_get_by_ssl(ssl); if (tor_tls && tor_tls->client_cipher_list_type) return tor_tls->client_cipher_list_type; /* If we reached this point, we just got a client hello. See if there is * a cipher list. */ if (!peer_ciphers) { log_info(LD_NET, "No ciphers on session"); res = CIPHERS_ERR; goto done; } /* Now we need to see if there are any ciphers whose presence means we're * dealing with an updated Tor. */ for (i = 0; i < sk_SSL_CIPHER_num(peer_ciphers); ++i) { const SSL_CIPHER *cipher = sk_SSL_CIPHER_value(peer_ciphers, i); const char *ciphername = SSL_CIPHER_get_name(cipher); if (strcmp(ciphername, TLS1_TXT_DHE_RSA_WITH_AES_128_SHA) && strcmp(ciphername, TLS1_TXT_DHE_RSA_WITH_AES_256_SHA) && strcmp(ciphername, SSL3_TXT_EDH_RSA_DES_192_CBC3_SHA) && strcmp(ciphername, "(NONE)")) { log_debug(LD_NET, "Got a non-version-1 cipher called '%s'", ciphername); // return 1; goto v2_or_higher; } } res = CIPHERS_V1; goto done; v2_or_higher: { const uint16_t *v2_cipher = v2_cipher_list; for (i = 0; i < sk_SSL_CIPHER_num(peer_ciphers); ++i) { const SSL_CIPHER *cipher = sk_SSL_CIPHER_value(peer_ciphers, i); uint16_t id = SSL_CIPHER_get_id(cipher) & 0xffff; if (id == 0x00ff) /* extended renegotiation indicator. */ continue; if (!id || id != *v2_cipher) { res = CIPHERS_UNRESTRICTED; goto dump_ciphers; } ++v2_cipher; } if (*v2_cipher != 0) { res = CIPHERS_UNRESTRICTED; goto dump_ciphers; } res = CIPHERS_V2; } dump_ciphers: { smartlist_t *elts = smartlist_new(); char *s; for (i = 0; i < sk_SSL_CIPHER_num(peer_ciphers); ++i) { const SSL_CIPHER *cipher = sk_SSL_CIPHER_value(peer_ciphers, i); const char *ciphername = SSL_CIPHER_get_name(cipher); smartlist_add(elts, (char*)ciphername); } s = smartlist_join_strings(elts, ":", 0, NULL); log_debug(LD_NET, "Got a %s V2/V3 cipher list from %s. It is: '%s'", (res == CIPHERS_V2) ? "fictitious" : "real", ADDR(tor_tls), s); tor_free(s); smartlist_free(elts); } done: if (tor_tls) return tor_tls->client_cipher_list_type = res; return res; } /** Return true iff the cipher list suggested by the client for ssl is * a list that indicates that the client knows how to do the v2 TLS connection * handshake. */ int tor_tls_client_is_using_v2_ciphers(const SSL *ssl) { STACK_OF(SSL_CIPHER) *ciphers; #ifdef HAVE_SSL_GET_CLIENT_CIPHERS ciphers = SSL_get_client_ciphers(ssl); #else SSL_SESSION *session; if (!(session = SSL_get_session((SSL *)ssl))) { log_info(LD_NET, "No session on TLS?"); return CIPHERS_ERR; } ciphers = session->ciphers; #endif /* defined(HAVE_SSL_GET_CLIENT_CIPHERS) */ return tor_tls_classify_client_ciphers(ssl, ciphers) >= CIPHERS_V2; } /** Invoked when we're accepting a connection on ssl, and the connection * changes state. We use this: *
  • To alter the state of the handshake partway through, so we * do not send or request extra certificates in v2 handshakes.
    • *
  • To detect renegotiation
*/ void tor_tls_server_info_callback(const SSL *ssl, int type, int val) { tor_tls_t *tls; (void) val; IF_BUG_ONCE(ssl == NULL) { return; // LCOV_EXCL_LINE } tor_tls_debug_state_callback(ssl, type, val); if (type != SSL_CB_ACCEPT_LOOP) return; OSSL_HANDSHAKE_STATE ssl_state = SSL_get_state(ssl); if (! STATE_IS_SW_SERVER_HELLO(ssl_state)) return; tls = tor_tls_get_by_ssl(ssl); if (tls) { /* Check whether we're watching for renegotiates. If so, this is one! */ if (tls->negotiated_callback) tls->got_renegotiate = 1; } else { log_warn(LD_BUG, "Couldn't look up the tls for an SSL*. How odd!"); return; } /* Now check the cipher list. */ if (tor_tls_client_is_using_v2_ciphers(ssl)) { if (tls->wasV2Handshake) return; /* We already turned this stuff off for the first handshake; * This is a renegotiation. */ /* Yes, we're casting away the const from ssl. This is very naughty of us. * Let's hope openssl doesn't notice! */ /* Set SSL_MODE_NO_AUTO_CHAIN to keep from sending back any extra certs. */ SSL_set_mode((SSL*) ssl, SSL_MODE_NO_AUTO_CHAIN); /* Don't send a hello request. */ SSL_set_verify((SSL*) ssl, SSL_VERIFY_NONE, NULL); if (tls) { tls->wasV2Handshake = 1; } else { /* LCOV_EXCL_START this line is not reachable */ log_warn(LD_BUG, "Couldn't look up the tls for an SSL*. How odd!"); /* LCOV_EXCL_STOP */ } } } /** Callback to get invoked on a server after we've read the list of ciphers * the client supports, but before we pick our own ciphersuite. * * We can't abuse an info_cb for this, since by the time one of the * client_hello info_cbs is called, we've already picked which ciphersuite to * use. * * Technically, this function is an abuse of this callback, since the point of * a session_secret_cb is to try to set up and/or verify a shared-secret for * authentication on the fly. But as long as we return 0, we won't actually be * setting up a shared secret, and all will be fine. */ int tor_tls_session_secret_cb(SSL *ssl, void *secret, int *secret_len, STACK_OF(SSL_CIPHER) *peer_ciphers, CONST_IF_OPENSSL_1_1_API SSL_CIPHER **cipher, void *arg) { (void) secret; (void) secret_len; (void) peer_ciphers; (void) cipher; (void) arg; if (tor_tls_classify_client_ciphers(ssl, peer_ciphers) == CIPHERS_UNRESTRICTED) { SSL_set_cipher_list(ssl, UNRESTRICTED_SERVER_CIPHER_LIST); } SSL_set_session_secret_cb(ssl, NULL, NULL); return 0; } static void tor_tls_setup_session_secret_cb(tor_tls_t *tls) { SSL_set_session_secret_cb(tls->ssl, tor_tls_session_secret_cb, NULL); } /** Create a new TLS object from a file descriptor, and a flag to * determine whether it is functioning as a server. */ tor_tls_t * tor_tls_new(tor_socket_t sock, int isServer) { BIO *bio = NULL; tor_tls_t *result = tor_malloc_zero(sizeof(tor_tls_t)); tor_tls_context_t *context = tor_tls_context_get(isServer); result->magic = TOR_TLS_MAGIC; check_no_tls_errors(); tor_assert(context); /* make sure somebody made it first */ if (!(result->ssl = SSL_new(context->ctx))) { tls_log_errors(NULL, LOG_WARN, LD_NET, "creating SSL object"); tor_free(result); goto err; } #ifdef SSL_set_tlsext_host_name /* Browsers use the TLS hostname extension, so we should too. */ if (!isServer) { char *fake_hostname = crypto_random_hostname(4,25, "www.",".com"); SSL_set_tlsext_host_name(result->ssl, fake_hostname); tor_free(fake_hostname); } #endif /* defined(SSL_set_tlsext_host_name) */ if (!SSL_set_cipher_list(result->ssl, isServer ? SERVER_CIPHER_LIST : CLIENT_CIPHER_LIST)) { tls_log_errors(NULL, LOG_WARN, LD_NET, "setting ciphers"); #ifdef SSL_set_tlsext_host_name SSL_set_tlsext_host_name(result->ssl, NULL); #endif SSL_free(result->ssl); tor_free(result); goto err; } result->socket = sock; bio = BIO_new_socket(sock, BIO_CLOSE); if (! bio) { tls_log_errors(NULL, LOG_WARN, LD_NET, "opening BIO"); #ifdef SSL_set_tlsext_host_name SSL_set_tlsext_host_name(result->ssl, NULL); #endif SSL_free(result->ssl); tor_free(result); goto err; } { int set_worked = SSL_set_ex_data(result->ssl, tor_tls_object_ex_data_index, result); if (!set_worked) { log_warn(LD_BUG, "Couldn't set the tls for an SSL*; connection will fail"); } } SSL_set_bio(result->ssl, bio, bio); tor_tls_context_incref(context); result->context = context; result->state = TOR_TLS_ST_HANDSHAKE; result->isServer = isServer; result->wantwrite_n = 0; result->last_write_count = (unsigned long) BIO_number_written(bio); result->last_read_count = (unsigned long) BIO_number_read(bio); if (result->last_write_count || result->last_read_count) { log_warn(LD_NET, "Newly created BIO has read count %lu, write count %lu", result->last_read_count, result->last_write_count); } if (isServer) { SSL_set_info_callback(result->ssl, tor_tls_server_info_callback); } else { SSL_set_info_callback(result->ssl, tor_tls_debug_state_callback); } if (isServer) tor_tls_setup_session_secret_cb(result); goto done; err: result = NULL; done: /* Not expected to get called. */ tls_log_errors(NULL, LOG_WARN, LD_NET, "creating tor_tls_t object"); return result; } /** Set cb to be called with argument arg whenever tls * next gets a client-side renegotiate in the middle of a read. Do not * invoke this function until after initial handshaking is done! */ void tor_tls_set_renegotiate_callback(tor_tls_t *tls, void (*cb)(tor_tls_t *, void *arg), void *arg) { tls->negotiated_callback = cb; tls->callback_arg = arg; tls->got_renegotiate = 0; if (cb) { SSL_set_info_callback(tls->ssl, tor_tls_server_info_callback); } else { SSL_set_info_callback(tls->ssl, tor_tls_debug_state_callback); } } /** If this version of openssl requires it, turn on renegotiation on * tls. */ void tor_tls_unblock_renegotiation(tor_tls_t *tls) { /* Yes, we know what we are doing here. No, we do not treat a renegotiation * as authenticating any earlier-received data. */ SSL_set_options(tls->ssl, SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION); } /** If this version of openssl supports it, turn off renegotiation on * tls. (Our protocol never requires this for security, but it's nice * to use belt-and-suspenders here.) */ void tor_tls_block_renegotiation(tor_tls_t *tls) { #ifdef SUPPORT_UNSAFE_RENEGOTIATION_FLAG tls->ssl->s3->flags &= ~SSL3_FLAGS_ALLOW_UNSAFE_LEGACY_RENEGOTIATION; #else (void) tls; #endif } /** Assert that the flags that allow legacy renegotiation are still set */ void tor_tls_assert_renegotiation_unblocked(tor_tls_t *tls) { #if defined(SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION) && \ SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION != 0 long options = SSL_get_options(tls->ssl); tor_assert(0 != (options & SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION)); #else (void) tls; #endif /* defined(SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION) && ... */ } /** * Tell the TLS library that the underlying socket for tls has been * closed, and the library should not attempt to free that socket itself. */ void tor_tls_release_socket(tor_tls_t *tls) { if (! tls) return; BIO *rbio, *wbio; rbio = SSL_get_rbio(tls->ssl); wbio = SSL_get_wbio(tls->ssl); if (rbio) { (void) BIO_set_close(rbio, BIO_NOCLOSE); } if (wbio && wbio != rbio) { (void) BIO_set_close(wbio, BIO_NOCLOSE); } } void tor_tls_impl_free_(tor_tls_impl_t *ssl) { if (!ssl) return; #ifdef SSL_set_tlsext_host_name SSL_set_tlsext_host_name(ssl, NULL); #endif SSL_free(ssl); } /** Underlying function for TLS reading. Reads up to len * characters from tls into cp. On success, returns the * number of characters read. On failure, returns TOR_TLS_ERROR, * TOR_TLS_CLOSE, TOR_TLS_WANTREAD, or TOR_TLS_WANTWRITE. */ MOCK_IMPL(int, tor_tls_read,(tor_tls_t *tls, char *cp, size_t len)) { int r, err; tor_assert(tls); tor_assert(tls->ssl); tor_assert(tls->state == TOR_TLS_ST_OPEN); tor_assert(lenssl, cp, (int)len); if (r > 0) { if (tls->got_renegotiate) { /* Renegotiation happened! */ log_info(LD_NET, "Got a TLS renegotiation from %s", ADDR(tls)); if (tls->negotiated_callback) tls->negotiated_callback(tls, tls->callback_arg); tls->got_renegotiate = 0; } return r; } err = tor_tls_get_error(tls, r, CATCH_ZERO, "reading", LOG_DEBUG, LD_NET); if (err == TOR_TLS_ZERORETURN_ || err == TOR_TLS_CLOSE) { log_debug(LD_NET,"read returned r=%d; TLS is closed",r); tls->state = TOR_TLS_ST_CLOSED; return TOR_TLS_CLOSE; } else { tor_assert(err != TOR_TLS_DONE); log_debug(LD_NET,"read returned r=%d, err=%d",r,err); return err; } } /** Total number of bytes that we've used TLS to send. Used to track TLS * overhead. */ STATIC uint64_t total_bytes_written_over_tls = 0; /** Total number of bytes that TLS has put on the network for us. Used to * track TLS overhead. */ STATIC uint64_t total_bytes_written_by_tls = 0; /** Underlying function for TLS writing. Write up to n * characters from cp onto tls. On success, returns the * number of characters written. On failure, returns TOR_TLS_ERROR, * TOR_TLS_WANTREAD, or TOR_TLS_WANTWRITE. */ int tor_tls_write(tor_tls_t *tls, const char *cp, size_t n) { int r, err; tor_assert(tls); tor_assert(tls->ssl); tor_assert(tls->state == TOR_TLS_ST_OPEN); tor_assert(n < INT_MAX); if (n == 0) return 0; if (tls->wantwrite_n) { /* if WANTWRITE last time, we must use the _same_ n as before */ tor_assert(n >= tls->wantwrite_n); log_debug(LD_NET,"resuming pending-write, (%d to flush, reusing %d)", (int)n, (int)tls->wantwrite_n); n = tls->wantwrite_n; tls->wantwrite_n = 0; } r = SSL_write(tls->ssl, cp, (int)n); err = tor_tls_get_error(tls, r, 0, "writing", LOG_INFO, LD_NET); if (err == TOR_TLS_DONE) { total_bytes_written_over_tls += r; return r; } if (err == TOR_TLS_WANTWRITE || err == TOR_TLS_WANTREAD) { tls->wantwrite_n = n; } return err; } /** Perform initial handshake on tls. When finished, returns * TOR_TLS_DONE. On failure, returns TOR_TLS_ERROR, TOR_TLS_WANTREAD, * or TOR_TLS_WANTWRITE. */ int tor_tls_handshake(tor_tls_t *tls) { int r; tor_assert(tls); tor_assert(tls->ssl); tor_assert(tls->state == TOR_TLS_ST_HANDSHAKE); check_no_tls_errors(); OSSL_HANDSHAKE_STATE oldstate = SSL_get_state(tls->ssl); if (tls->isServer) { log_debug(LD_HANDSHAKE, "About to call SSL_accept on %p (%s)", tls, SSL_state_string_long(tls->ssl)); r = SSL_accept(tls->ssl); } else { log_debug(LD_HANDSHAKE, "About to call SSL_connect on %p (%s)", tls, SSL_state_string_long(tls->ssl)); r = SSL_connect(tls->ssl); } OSSL_HANDSHAKE_STATE newstate = SSL_get_state(tls->ssl); if (oldstate != newstate) log_debug(LD_HANDSHAKE, "After call, %p was in state %s", tls, SSL_state_string_long(tls->ssl)); /* We need to call this here and not earlier, since OpenSSL has a penchant * for clearing its flags when you say accept or connect. */ tor_tls_unblock_renegotiation(tls); r = tor_tls_get_error(tls,r,0, "handshaking", LOG_INFO, LD_HANDSHAKE); if (ERR_peek_error() != 0) { tls_log_errors(tls, tls->isServer ? LOG_INFO : LOG_WARN, LD_HANDSHAKE, "handshaking"); return TOR_TLS_ERROR_MISC; } if (r == TOR_TLS_DONE) { tls->state = TOR_TLS_ST_OPEN; return tor_tls_finish_handshake(tls); } return r; } /** Perform the final part of the initial TLS handshake on tls. This * should be called for the first handshake only: it determines whether the v1 * or the v2 handshake was used, and adjusts things for the renegotiation * handshake as appropriate. * * tor_tls_handshake() calls this on its own; you only need to call this if * bufferevent is doing the handshake for you. */ int tor_tls_finish_handshake(tor_tls_t *tls) { int r = TOR_TLS_DONE; check_no_tls_errors(); if (tls->isServer) { SSL_set_info_callback(tls->ssl, NULL); SSL_set_verify(tls->ssl, SSL_VERIFY_PEER, always_accept_verify_cb); SSL_clear_mode(tls->ssl, SSL_MODE_NO_AUTO_CHAIN); if (tor_tls_client_is_using_v2_ciphers(tls->ssl)) { /* This check is redundant, but back when we did it in the callback, * we might have not been able to look up the tor_tls_t if the code * was buggy. Fixing that. */ if (!tls->wasV2Handshake) { log_warn(LD_BUG, "For some reason, wasV2Handshake didn't" " get set. Fixing that."); } tls->wasV2Handshake = 1; log_debug(LD_HANDSHAKE, "Completed V2 TLS handshake with client; waiting" " for renegotiation."); } else { tls->wasV2Handshake = 0; } } else { /* Client-side */ tls->wasV2Handshake = 1; /* XXXX this can move, probably? -NM */ if (SSL_set_cipher_list(tls->ssl, SERVER_CIPHER_LIST) == 0) { tls_log_errors(NULL, LOG_WARN, LD_HANDSHAKE, "re-setting ciphers"); r = TOR_TLS_ERROR_MISC; } } tls_log_errors(NULL, LOG_WARN, LD_NET, "finishing the handshake"); return r; } /** Return true iff this TLS connection is authenticated. */ int tor_tls_peer_has_cert(tor_tls_t *tls) { X509 *cert; cert = SSL_get_peer_certificate(tls->ssl); tls_log_errors(tls, LOG_WARN, LD_HANDSHAKE, "getting peer certificate"); if (!cert) return 0; X509_free(cert); return 1; } /** Return a newly allocated copy of the peer certificate, or NULL if there * isn't one. */ MOCK_IMPL(tor_x509_cert_t *, tor_tls_get_peer_cert,(tor_tls_t *tls)) { X509 *cert; cert = SSL_get_peer_certificate(tls->ssl); tls_log_errors(tls, LOG_WARN, LD_HANDSHAKE, "getting peer certificate"); if (!cert) return NULL; return tor_x509_cert_new(cert); } /** Return a newly allocated copy of the cerficate we used on the connection, * or NULL if somehow we didn't use one. */ MOCK_IMPL(tor_x509_cert_t *, tor_tls_get_own_cert,(tor_tls_t *tls)) { X509 *cert = SSL_get_certificate(tls->ssl); tls_log_errors(tls, LOG_WARN, LD_HANDSHAKE, "getting own-connection certificate"); if (!cert) return NULL; /* Fun inconsistency: SSL_get_peer_certificate increments the reference * count, but SSL_get_certificate does not. */ X509 *duplicate = X509_dup(cert); if (BUG(duplicate == NULL)) return NULL; return tor_x509_cert_new(duplicate); } /** Helper function: try to extract a link certificate and an identity * certificate from tls, and store them in *cert_out and * *id_cert_out respectively. Log all messages at level * severity. * * Note that a reference is added both of the returned certificates. */ MOCK_IMPL(void, try_to_extract_certs_from_tls,(int severity, tor_tls_t *tls, X509 **cert_out, X509 **id_cert_out)) { X509 *cert = NULL, *id_cert = NULL; STACK_OF(X509) *chain = NULL; int num_in_chain, i; *cert_out = *id_cert_out = NULL; if (!(cert = SSL_get_peer_certificate(tls->ssl))) return; *cert_out = cert; if (!(chain = SSL_get_peer_cert_chain(tls->ssl))) return; num_in_chain = sk_X509_num(chain); /* 1 means we're receiving (server-side), and it's just the id_cert. * 2 means we're connecting (client-side), and it's both the link * cert and the id_cert. */ if (num_in_chain < 1) { log_fn(severity,LD_PROTOCOL, "Unexpected number of certificates in chain (%d)", num_in_chain); return; } for (i=0; itls. */ int tor_tls_get_pending_bytes(tor_tls_t *tls) { tor_assert(tls); return SSL_pending(tls->ssl); } /** If tls requires that the next write be of a particular size, * return that size. Otherwise, return 0. */ size_t tor_tls_get_forced_write_size(tor_tls_t *tls) { return tls->wantwrite_n; } /** Sets n_read and n_written to the number of bytes read and written, * respectively, on the raw socket used by tls since the last time this * function was called on tls. */ void tor_tls_get_n_raw_bytes(tor_tls_t *tls, size_t *n_read, size_t *n_written) { BIO *wbio, *tmpbio; unsigned long r, w; r = (unsigned long) BIO_number_read(SSL_get_rbio(tls->ssl)); /* We want the number of bytes actually for real written. Unfortunately, * sometimes OpenSSL replaces the wbio on tls->ssl with a buffering bio, * which makes the answer turn out wrong. Let's cope with that. Note * that this approach will fail if we ever replace tls->ssl's BIOs with * buffering bios for reasons of our own. As an alternative, we could * save the original BIO for tls->ssl in the tor_tls_t structure, but * that would be tempting fate. */ wbio = SSL_get_wbio(tls->ssl); #if OPENSSL_VERSION_NUMBER >= OPENSSL_VER(1,1,0,0,5) /* BIO structure is opaque as of OpenSSL 1.1.0-pre5-dev. Again, not * supposed to use this form of the version macro, but the OpenSSL developers * introduced major API changes in the pre-release stage. */ if (BIO_method_type(wbio) == BIO_TYPE_BUFFER && (tmpbio = BIO_next(wbio)) != NULL) wbio = tmpbio; #else /* !(OPENSSL_VERSION_NUMBER >= OPENSSL_VER(1,1,0,0,5)) */ if (wbio->method == BIO_f_buffer() && (tmpbio = BIO_next(wbio)) != NULL) wbio = tmpbio; #endif /* OPENSSL_VERSION_NUMBER >= OPENSSL_VER(1,1,0,0,5) */ w = (unsigned long) BIO_number_written(wbio); /* We are ok with letting these unsigned ints go "negative" here: * If we wrapped around, this should still give us the right answer, unless * we wrapped around by more than ULONG_MAX since the last time we called * this function. */ *n_read = (size_t)(r - tls->last_read_count); *n_written = (size_t)(w - tls->last_write_count); if (*n_read > INT_MAX || *n_written > INT_MAX) { log_warn(LD_BUG, "Preposterously large value in tor_tls_get_n_raw_bytes. " "r=%lu, last_read=%lu, w=%lu, last_written=%lu", r, tls->last_read_count, w, tls->last_write_count); } total_bytes_written_by_tls += *n_written; tls->last_read_count = r; tls->last_write_count = w; } /** Return a ratio of the bytes that TLS has sent to the bytes that we've told * it to send. Used to track whether our TLS records are getting too tiny. */ MOCK_IMPL(double, tls_get_write_overhead_ratio,(void)) { if (total_bytes_written_over_tls == 0) return 1.0; return ((double)total_bytes_written_by_tls) / ((double)total_bytes_written_over_tls); } /** Implement check_no_tls_errors: If there are any pending OpenSSL * errors, log an error message. */ void check_no_tls_errors_(const char *fname, int line) { if (ERR_peek_error() == 0) return; log_warn(LD_CRYPTO, "Unhandled OpenSSL errors found at %s:%d: ", tor_fix_source_file(fname), line); tls_log_errors(NULL, LOG_WARN, LD_NET, NULL); } /** Return true iff the initial TLS connection at tls did not use a v2 * TLS handshake. Output is undefined if the handshake isn't finished. */ int tor_tls_used_v1_handshake(tor_tls_t *tls) { return ! tls->wasV2Handshake; } /** Return true iff the server TLS connection tls got the renegotiation * request it was waiting for. */ int tor_tls_server_got_renegotiate(tor_tls_t *tls) { return tls->got_renegotiate; } #ifndef HAVE_SSL_GET_CLIENT_RANDOM static size_t SSL_get_client_random(SSL *s, uint8_t *out, size_t len) { if (len == 0) return SSL3_RANDOM_SIZE; tor_assert(len == SSL3_RANDOM_SIZE); tor_assert(s->s3); memcpy(out, s->s3->client_random, len); return len; } #endif /* !defined(HAVE_SSL_GET_CLIENT_RANDOM) */ #ifndef HAVE_SSL_GET_SERVER_RANDOM static size_t SSL_get_server_random(SSL *s, uint8_t *out, size_t len) { if (len == 0) return SSL3_RANDOM_SIZE; tor_assert(len == SSL3_RANDOM_SIZE); tor_assert(s->s3); memcpy(out, s->s3->server_random, len); return len; } #endif /* !defined(HAVE_SSL_GET_SERVER_RANDOM) */ #ifndef HAVE_SSL_SESSION_GET_MASTER_KEY size_t SSL_SESSION_get_master_key(SSL_SESSION *s, uint8_t *out, size_t len) { tor_assert(s); if (len == 0) return s->master_key_length; tor_assert(len == (size_t)s->master_key_length); tor_assert(out); memcpy(out, s->master_key, len); return len; } #endif /* !defined(HAVE_SSL_SESSION_GET_MASTER_KEY) */ /** Set the DIGEST256_LEN buffer at secrets_out to the value used in * the v3 handshake to prove that the client knows the TLS secrets for the * connection tls. Return 0 on success, -1 on failure. */ MOCK_IMPL(int, tor_tls_get_tlssecrets,(tor_tls_t *tls, uint8_t *secrets_out)) { #define TLSSECRET_MAGIC "Tor V3 handshake TLS cross-certification" uint8_t buf[128]; size_t len; tor_assert(tls); SSL *const ssl = tls->ssl; SSL_SESSION *const session = SSL_get_session(ssl); tor_assert(ssl); tor_assert(session); const size_t server_random_len = SSL_get_server_random(ssl, NULL, 0); const size_t client_random_len = SSL_get_client_random(ssl, NULL, 0); const size_t master_key_len = SSL_SESSION_get_master_key(session, NULL, 0); tor_assert(server_random_len); tor_assert(client_random_len); tor_assert(master_key_len); len = client_random_len + server_random_len + strlen(TLSSECRET_MAGIC) + 1; tor_assert(len <= sizeof(buf)); { size_t r = SSL_get_client_random(ssl, buf, client_random_len); tor_assert(r == client_random_len); } { size_t r = SSL_get_server_random(ssl, buf+client_random_len, server_random_len); tor_assert(r == server_random_len); } uint8_t *master_key = tor_malloc_zero(master_key_len); { size_t r = SSL_SESSION_get_master_key(session, master_key, master_key_len); tor_assert(r == master_key_len); } uint8_t *nextbuf = buf + client_random_len + server_random_len; memcpy(nextbuf, TLSSECRET_MAGIC, strlen(TLSSECRET_MAGIC) + 1); /* The value is an HMAC, using the TLS master key as the HMAC key, of client_random | server_random | TLSSECRET_MAGIC */ crypto_hmac_sha256((char*)secrets_out, (char*)master_key, master_key_len, (char*)buf, len); memwipe(buf, 0, sizeof(buf)); memwipe(master_key, 0, master_key_len); tor_free(master_key); return 0; } /** Using the RFC5705 key material exporting construction, and the * provided context (context_len bytes long) and * label (a NUL-terminated string), compute a 32-byte secret in * secrets_out that only the parties to this TLS session can * compute. Return 0 on success and -1 on failure. */ MOCK_IMPL(int, tor_tls_export_key_material,(tor_tls_t *tls, uint8_t *secrets_out, const uint8_t *context, size_t context_len, const char *label)) { tor_assert(tls); tor_assert(tls->ssl); int r = SSL_export_keying_material(tls->ssl, secrets_out, DIGEST256_LEN, label, strlen(label), context, context_len, 1); return (r == 1) ? 0 : -1; } /** Examine the amount of memory used and available for buffers in tls. * Set *rbuf_capacity to the amount of storage allocated for the read * buffer and *rbuf_bytes to the amount actually used. * Set *wbuf_capacity to the amount of storage allocated for the write * buffer and *wbuf_bytes to the amount actually used. * * Return 0 on success, -1 on failure.*/ int tor_tls_get_buffer_sizes(tor_tls_t *tls, size_t *rbuf_capacity, size_t *rbuf_bytes, size_t *wbuf_capacity, size_t *wbuf_bytes) { #if OPENSSL_VERSION_NUMBER >= OPENSSL_V_SERIES(1,1,0) (void)tls; (void)rbuf_capacity; (void)rbuf_bytes; (void)wbuf_capacity; (void)wbuf_bytes; return -1; #else /* !(OPENSSL_VERSION_NUMBER >= OPENSSL_V_SERIES(1,1,0)) */ if (tls->ssl->s3->rbuf.buf) *rbuf_capacity = tls->ssl->s3->rbuf.len; else *rbuf_capacity = 0; if (tls->ssl->s3->wbuf.buf) *wbuf_capacity = tls->ssl->s3->wbuf.len; else *wbuf_capacity = 0; *rbuf_bytes = tls->ssl->s3->rbuf.left; *wbuf_bytes = tls->ssl->s3->wbuf.left; return 0; #endif /* OPENSSL_VERSION_NUMBER >= OPENSSL_V_SERIES(1,1,0) */ } /** Check whether the ECC group requested is supported by the current OpenSSL * library instance. Return 1 if the group is supported, and 0 if not. */ int evaluate_ecgroup_for_tls(const char *ecgroup) { EC_KEY *ec_key; int nid; int ret; if (!ecgroup) nid = NID_tor_default_ecdhe_group; else if (!strcasecmp(ecgroup, "P256")) nid = NID_X9_62_prime256v1; else if (!strcasecmp(ecgroup, "P224")) nid = NID_secp224r1; else return 0; ec_key = EC_KEY_new_by_curve_name(nid); ret = (ec_key != NULL); EC_KEY_free(ec_key); return ret; }