/* Copyright (c) 2003, Roger Dingledine. * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson. * Copyright (c) 2007-2008, The Tor Project, Inc. */ /* See LICENSE for licensing information */ /* $Id$ */ const char tortls_c_id[] = "$Id$"; /** * \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" #include #include #include #include #include #include #include #include #if OPENSSL_VERSION_NUMBER < 0x00907000l #error "We require openssl >= 0.9.7" #endif #define CRYPTO_PRIVATE /* to import prototypes from crypto.h */ #include "crypto.h" #include "tortls.h" #include "util.h" #include "log.h" #include "container.h" #include "ht.h" #include /* Enable the "v2" TLS handshake. */ #define V2_HANDSHAKE_SERVER #define V2_HANDSHAKE_CLIENT /* Copied from or.h */ #define LEGAL_NICKNAME_CHARACTERS \ "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789" /** How long do identity certificates live? (sec) */ #define IDENTITY_CERT_LIFETIME (365*24*60*60) #define ADDR(tls) (((tls) && (tls)->address) ? tls->address : "peer") /** Structure holding the TLS state for a single connection. */ typedef struct tor_tls_context_t { int refcnt; SSL_CTX *ctx; X509 *my_cert; X509 *my_id_cert; crypto_pk_env_t *key; } tor_tls_context_t; /** Holds a SSL object and its associated data. Members are only * accessed from within tortls.c. */ struct tor_tls_t { HT_ENTRY(tor_tls_t) node; tor_tls_context_t *context; /** A link to the context object for this tls */ SSL *ssl; /**< An OpenSSL SSL object. */ int socket; /**< The underlying file descriptor for this TLS connection. */ char *address; /**< An address to log when describing this connectinon. */ enum { TOR_TLS_ST_HANDSHAKE, TOR_TLS_ST_OPEN, TOR_TLS_ST_GOTCLOSE, TOR_TLS_ST_SENTCLOSE, TOR_TLS_ST_CLOSED, TOR_TLS_ST_RENEGOTIATE, } state : 3; /**< The current SSL state, depending on which operations have * completed successfully. */ unsigned int isServer:1; /**< True iff this is a server-side connection */ unsigned int wasV2Handshake:1; /**< True iff the original handshake for * this connection used the updated version * of the connection protocol (client sends * different cipher list, server sends only * one certificate). */ /** True iff we should call negotiated_callback when we're done reading. */ unsigned int got_renegotiate:1; size_t wantwrite_n; /**< 0 normally, >0 if we returned wantwrite last * time. */ /** Last values retrieved from BIO_number_read()/write(); see * tor_tls_get_n_raw_bytes() for usage. */ unsigned long last_write_count; unsigned long last_read_count; /** If set, a callback to invoke whenever the client tries to renegotiate * the handshake. */ void (*negotiated_callback)(tor_tls_t *tls, void *arg); /** Argument to pass to negotiated_callback. */ void *callback_arg; }; /** Helper: compare tor_tls_t objects by its SSL. */ static INLINE int tor_tls_entries_eq(const tor_tls_t *a, const tor_tls_t *b) { return a->ssl == b->ssl; } /** Helper: return a hash value for a tor_tls_t by its SSL. */ static INLINE unsigned int tor_tls_entry_hash(const tor_tls_t *a) { #if SIZEOF_INT == SIZEOF_VOID_P return ((unsigned int)(uintptr_t)a->ssl); #else return (unsigned int) ((((uint64_t)a->ssl)>>2) & UINT_MAX); #endif } /** Map from SSL* pointers to tor_tls_t objects using those pointers. */ static HT_HEAD(tlsmap, tor_tls_t) tlsmap_root = HT_INITIALIZER(); HT_PROTOTYPE(tlsmap, tor_tls_t, node, tor_tls_entry_hash, tor_tls_entries_eq) HT_GENERATE(tlsmap, tor_tls_t, node, tor_tls_entry_hash, tor_tls_entries_eq, 0.6, malloc, realloc, free) /** Helper: given a SSL* pointer, return the tor_tls_t object using that * pointer. */ static INLINE tor_tls_t * tor_tls_get_by_ssl(const SSL *ssl) { tor_tls_t search, *result; memset(&search, 0, sizeof(search)); search.ssl = (SSL*)ssl; result = HT_FIND(tlsmap, &tlsmap_root, &search); return result; } static void tor_tls_context_decref(tor_tls_context_t *ctx); static void tor_tls_context_incref(tor_tls_context_t *ctx); static X509* tor_tls_create_certificate(crypto_pk_env_t *rsa, crypto_pk_env_t *rsa_sign, const char *cname, const char *cname_sign, unsigned int lifetime); /** Global tls context. We keep it here because nobody else needs to * touch it. */ static tor_tls_context_t *global_tls_context = NULL; /** 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) /** Log all pending tls errors at level severity. Use * doing to describe our current activities. */ static void tls_log_errors(tor_tls_t *tls, int severity, const char *doing) { unsigned long err; const char *msg, *lib, *func, *addr; addr = tls ? tls->address : NULL; while ((err = ERR_get_error()) != 0) { 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 (doing) { log(severity, LD_NET, "TLS error while %s%s%s: %s (in %s:%s)", doing, addr?" with ":"", addr?addr:"", msg, lib, func); } else { log(severity, LD_NET, "TLS error%s%s: %s (in %s:%s)", addr?" with ":"", addr?addr:"", msg, lib, func); } } } /** Convert an errno (or a WSAerrno on windows) into a TOR_TLS_* error * code. */ static int tor_errno_to_tls_error(int e) { #if defined(MS_WINDOWS) && !defined(USE_BSOCKETS) switch (e) { case WSAECONNRESET: // most common return TOR_TLS_ERROR_CONNRESET; case WSAETIMEDOUT: return TOR_TLS_ERROR_TIMEOUT; case WSAENETUNREACH: case WSAEHOSTUNREACH: return TOR_TLS_ERROR_NO_ROUTE; case WSAECONNREFUSED: return TOR_TLS_ERROR_CONNREFUSED; // least common default: return TOR_TLS_ERROR_MISC; } #else switch (e) { case ECONNRESET: // most common return TOR_TLS_ERROR_CONNRESET; case ETIMEDOUT: return TOR_TLS_ERROR_TIMEOUT; case EHOSTUNREACH: case ENETUNREACH: return TOR_TLS_ERROR_NO_ROUTE; case ECONNREFUSED: return TOR_TLS_ERROR_CONNREFUSED; // least common default: return TOR_TLS_ERROR_MISC; } #endif } /** Given a TOR_TLS_* error code, return a string equivalent. */ const char * tor_tls_err_to_string(int err) { if (err >= 0) return "[Not an error.]"; switch (err) { case TOR_TLS_ERROR_MISC: return "misc error"; case TOR_TLS_ERROR_IO: return "unexpected close"; case TOR_TLS_ERROR_CONNREFUSED: return "connection refused"; case TOR_TLS_ERROR_CONNRESET: return "connection reset"; case TOR_TLS_ERROR_NO_ROUTE: return "host unreachable"; case TOR_TLS_ERROR_TIMEOUT: return "connection timed out"; case TOR_TLS_CLOSE: return "closed"; case TOR_TLS_WANTREAD: return "want to read"; case TOR_TLS_WANTWRITE: return "want to write"; default: return "(unknown error code)"; } } #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. */ static int tor_tls_get_error(tor_tls_t *tls, int r, int extra, const char *doing, int severity) { 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) { log(severity, LD_NET, "TLS error: unexpected close while %s", doing); tor_error = TOR_TLS_ERROR_IO; } else { int e = tor_socket_errno(tls->socket); log(severity, LD_NET, "TLS error: (errno=%d: %s)", doing, e, tor_socket_strerror(e)); tor_error = tor_errno_to_tls_error(e); } tls_log_errors(tls, severity, doing); return tor_error; case SSL_ERROR_ZERO_RETURN: if (extra&CATCH_ZERO) return _TOR_TLS_ZERORETURN; log(severity, LD_NET, "TLS connection closed while %s", doing); tls_log_errors(tls, severity, doing); return TOR_TLS_CLOSE; default: tls_log_errors(tls, severity, doing); return TOR_TLS_ERROR_MISC; } } /** Initialize OpenSSL, unless it has already been initialized. */ static void tor_tls_init(void) { if (!tls_library_is_initialized) { SSL_library_init(); SSL_load_error_strings(); crypto_global_init(-1); tls_library_is_initialized = 1; } } /** Free all global TLS structures. */ void tor_tls_free_all(void) { if (global_tls_context) { tor_tls_context_decref(global_tls_context); global_tls_context = NULL; } } /** 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. */ static int always_accept_verify_cb(int preverify_ok, X509_STORE_CTX *x509_ctx) { (void) preverify_ok; (void) x509_ctx; return 1; } /** Return a newly allocated X509 name with commonName cname. */ static X509_NAME * tor_x509_name_new(const char *cname) { int nid; X509_NAME *name; if (!(name = X509_NAME_new())) return NULL; if ((nid = OBJ_txt2nid("commonName")) == NID_undef) goto error; if (!(X509_NAME_add_entry_by_NID(name, nid, MBSTRING_ASC, (unsigned char*)cname, -1, -1, 0))) goto error; return name; error: X509_NAME_free(name); return NULL; } /** Generate and sign an X509 certificate with the public key rsa, * signed by the private key rsa_sign. The commonName of the * certificate will be cname; the commonName of the issuer will be * cname_sign. The cert will be valid for cert_lifetime seconds * starting from now. Return a certificate on success, NULL on * failure. */ static X509 * tor_tls_create_certificate(crypto_pk_env_t *rsa, crypto_pk_env_t *rsa_sign, const char *cname, const char *cname_sign, unsigned int cert_lifetime) { time_t start_time, end_time; EVP_PKEY *sign_pkey = NULL, *pkey=NULL; X509 *x509 = NULL; X509_NAME *name = NULL, *name_issuer=NULL; tor_tls_init(); start_time = time(NULL); tor_assert(rsa); tor_assert(cname); tor_assert(rsa_sign); tor_assert(cname_sign); if (!(sign_pkey = _crypto_pk_env_get_evp_pkey(rsa_sign,1))) goto error; if (!(pkey = _crypto_pk_env_get_evp_pkey(rsa,0))) goto error; if (!(x509 = X509_new())) goto error; if (!(X509_set_version(x509, 2))) goto error; if (!(ASN1_INTEGER_set(X509_get_serialNumber(x509), (long)start_time))) goto error; if (!(name = tor_x509_name_new(cname))) goto error; if (!(X509_set_subject_name(x509, name))) goto error; if (!(name_issuer = tor_x509_name_new(cname_sign))) goto error; if (!(X509_set_issuer_name(x509, name_issuer))) goto error; if (!X509_time_adj(X509_get_notBefore(x509),0,&start_time)) goto error; end_time = start_time + cert_lifetime; if (!X509_time_adj(X509_get_notAfter(x509),0,&end_time)) goto error; if (!X509_set_pubkey(x509, pkey)) goto error; if (!X509_sign(x509, sign_pkey, EVP_sha1())) goto error; goto done; error: if (x509) { X509_free(x509); x509 = NULL; } done: tls_log_errors(NULL, LOG_WARN, "generating certificate"); if (sign_pkey) EVP_PKEY_free(sign_pkey); if (pkey) EVP_PKEY_free(pkey); if (name) X509_NAME_free(name); if (name_issuer) X509_NAME_free(name_issuer); return x509; } #define SERVER_CIPHER_LIST \ (TLS1_TXT_DHE_RSA_WITH_AES_256_SHA ":" \ TLS1_TXT_DHE_RSA_WITH_AES_128_SHA ":" \ SSL3_TXT_EDH_RSA_DES_192_CBC3_SHA) /* Note: for setting up your own private testing network with link crypto * disabled, set the cipher lists to your 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. */ #if OPENSSL_VERSION_NUMBER >= 0x00908020l #define CLIENT_CIPHER_LIST \ (TLS1_TXT_ECDHE_ECDSA_WITH_AES_256_CBC_SHA ":" \ TLS1_TXT_ECDHE_RSA_WITH_AES_256_CBC_SHA ":" \ TLS1_TXT_DHE_RSA_WITH_AES_256_SHA ":" \ TLS1_TXT_DHE_DSS_WITH_AES_256_SHA ":" \ TLS1_TXT_ECDH_RSA_WITH_AES_256_CBC_SHA ":" \ TLS1_TXT_ECDH_ECDSA_WITH_AES_256_CBC_SHA ":" \ TLS1_TXT_RSA_WITH_AES_256_SHA ":" \ TLS1_TXT_ECDHE_ECDSA_WITH_RC4_128_SHA ":" \ TLS1_TXT_ECDHE_ECDSA_WITH_AES_128_CBC_SHA ":" \ TLS1_TXT_ECDHE_RSA_WITH_RC4_128_SHA ":" \ TLS1_TXT_ECDHE_RSA_WITH_AES_128_CBC_SHA ":" \ TLS1_TXT_DHE_RSA_WITH_AES_128_SHA ":" \ TLS1_TXT_DHE_DSS_WITH_AES_128_SHA ":" \ TLS1_TXT_ECDH_RSA_WITH_RC4_128_SHA":" \ TLS1_TXT_ECDH_RSA_WITH_AES_128_CBC_SHA":" \ TLS1_TXT_ECDH_ECDSA_WITH_RC4_128_SHA ":" \ TLS1_TXT_ECDH_ECDSA_WITH_AES_128_CBC_SHA ":" \ SSL3_TXT_RSA_RC4_128_MD5 ":" \ SSL3_TXT_RSA_RC4_128_SHA ":" \ TLS1_TXT_RSA_WITH_AES_128_SHA ":" \ TLS1_TXT_ECDHE_ECDSA_WITH_DES_192_CBC3_SHA ":" \ TLS1_TXT_ECDHE_RSA_WITH_DES_192_CBC3_SHA ":" \ SSL3_TXT_EDH_RSA_DES_192_CBC3_SHA ":" \ SSL3_TXT_EDH_DSS_DES_192_CBC3_SHA ":" \ TLS1_TXT_ECDH_RSA_WITH_DES_192_CBC3_SHA ":" \ TLS1_TXT_ECDH_ECDSA_WITH_DES_192_CBC3_SHA ":" \ /*SSL3_TXT_RSA_FIPS_WITH_3DES_EDE_CBC_SHA ":"*/ \ SSL3_TXT_RSA_DES_192_CBC3_SHA) /* SSL3_TXT_RSA_FIPS_WITH_3DES_EDE_CBC_SHA is commented out because it doesn't * really exist; if I understand correctly, it's a bit of silliness that * netscape did on its own before any standard for what they wanted was * formally approved. Nonetheless, Firefox still uses it, so we need to * fake it at some point soon. XXXX021 -NM */ #else /* Ug. We don't have as many ciphers with openssl 0.9.7 as we'd like. Fix * this list into something that sucks less. */ #define CLIENT_CIPHER_LIST \ (TLS1_TXT_DHE_RSA_WITH_AES_256_SHA ":" \ TLS1_TXT_DHE_RSA_WITH_AES_128_SHA ":" \ SSL3_TXT_EDH_RSA_DES_192_CBC3_SHA ":" \ SSL3_TXT_RSA_RC4_128_SHA) #endif #ifndef V2_HANDSHAKE_CLIENT #undef CLIENT_CIPHER_LIST #define CLIENT_CIPHER_LIST (TLS1_TXT_DHE_RSA_WITH_AES_128_SHA ":" \ SSL3_TXT_EDH_RSA_DES_192_CBC3_SHA) #endif /** Remove a reference to ctx, and free it if it has no more * references. */ static void tor_tls_context_decref(tor_tls_context_t *ctx) { tor_assert(ctx); if (--ctx->refcnt == 0) { SSL_CTX_free(ctx->ctx); X509_free(ctx->my_cert); X509_free(ctx->my_id_cert); crypto_free_pk_env(ctx->key); tor_free(ctx); } } /** Increase the reference count of ctx. */ static void tor_tls_context_incref(tor_tls_context_t *ctx) { ++ctx->refcnt; } /** Create a new TLS context for use with Tor TLS handshakes. * identity should be set to the identity key used to sign the * certificate, and nickname set to the nickname to use. * * You can call this function multiple times. Each time you call it, * it generates new certificates; all new connections will use * the new SSL context. */ int tor_tls_context_new(crypto_pk_env_t *identity, unsigned int key_lifetime) { crypto_pk_env_t *rsa = NULL; crypto_dh_env_t *dh = NULL; EVP_PKEY *pkey = NULL; tor_tls_context_t *result = NULL; X509 *cert = NULL, *idcert = NULL; char *nickname = NULL, *nn2 = NULL; tor_tls_init(); nickname = crypto_random_hostname(8, 20, "www.", ".net"); nn2 = crypto_random_hostname(8, 20, "www.", ".net"); /* Generate short-term RSA key. */ if (!(rsa = crypto_new_pk_env())) 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; } 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); #ifdef EVERYONE_HAS_AES /* Tell OpenSSL to only use TLS1 */ if (!(result->ctx = SSL_CTX_new(TLSv1_method()))) goto error; #else /* Tell OpenSSL to use SSL3 or TLS1 but not SSL2. */ if (!(result->ctx = SSL_CTX_new(SSLv23_method()))) goto error; SSL_CTX_set_options(result->ctx, SSL_OP_NO_SSLv2); #endif SSL_CTX_set_options(result->ctx, SSL_OP_SINGLE_DH_USE); 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; dh = crypto_dh_new(); SSL_CTX_set_tmp_dh(result->ctx, _crypto_dh_env_get_dh(dh)); crypto_dh_free(dh); 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); /* Free the old context if one exists. */ if (global_tls_context) { /* This is safe even if there are open connections: OpenSSL does * reference counting with SSL and SSL_CTX objects. */ tor_tls_context_decref(global_tls_context); } global_tls_context = result; if (rsa) crypto_free_pk_env(rsa); tor_free(nickname); tor_free(nn2); return 0; error: tls_log_errors(NULL, LOG_WARN, "creating TLS context"); tor_free(nickname); tor_free(nn2); if (pkey) EVP_PKEY_free(pkey); if (rsa) crypto_free_pk_env(rsa); if (dh) crypto_dh_free(dh); if (result) tor_tls_context_decref(result); if (cert) X509_free(cert); if (idcert) X509_free(idcert); return -1; } #ifdef V2_HANDSHAKE_SERVER /** Return true iff the cipher list suggested by the client for ssl is * a list that indicates that the client know how to do the v2 TLS connection * handshake. */ static int tor_tls_client_is_using_v2_ciphers(const SSL *ssl, const char *address) { int i; SSL_SESSION *session; /* If we reached this point, we just got a client hello. See if there is * a cipher list. */ if (!(session = SSL_get_session((SSL *)ssl))) { log_warn(LD_NET, "No session on TLS?"); return 0; } if (!session->ciphers) { log_warn(LD_NET, "No ciphers on session"); return 0; } /* 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(session->ciphers); ++i) { SSL_CIPHER *cipher = sk_SSL_CIPHER_value(session->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)")) { /* XXXX should be ld_debug */ log_info(LD_NET, "Got a non-version-1 cipher called '%s'", ciphername); // return 1; goto dump_list; } } return 0; dump_list: { smartlist_t *elts = smartlist_create(); char *s; for (i = 0; i < sk_SSL_CIPHER_num(session->ciphers); ++i) { SSL_CIPHER *cipher = sk_SSL_CIPHER_value(session->ciphers, i); const char *ciphername = SSL_CIPHER_get_name(cipher); smartlist_add(elts, (char*)ciphername); } s = smartlist_join_strings(elts, ":", 0, NULL); log_info(LD_NET, "Got a non-version-1 cipher list from %s. It is: '%s'", s, address); tor_free(s); smartlist_free(elts); } return 1; } /** 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
*/ static void tor_tls_server_info_callback(const SSL *ssl, int type, int val) { tor_tls_t *tls; (void) val; if (type != SSL_CB_ACCEPT_LOOP) return; if (ssl->state != SSL3_ST_SW_SRVR_HELLO_A) 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!"); } /* Now check the cipher list. */ if (tor_tls_client_is_using_v2_ciphers(ssl, ADDR(tls))) { /*XXXX_TLS keep this from happening more than once! */ /* 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 { log_warn(LD_BUG, "Couldn't look up the tls for an SSL*. How odd!"); } } } #endif /** 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(int sock, int isServer) { BIO *bio = NULL; tor_tls_t *result = tor_malloc_zero(sizeof(tor_tls_t)); tor_assert(global_tls_context); /* make sure somebody made it first */ if (!(result->ssl = SSL_new(global_tls_context->ctx))) { tls_log_errors(NULL, LOG_WARN, "generating TLS context"); tor_free(result); return NULL; } if (!SSL_set_cipher_list(result->ssl, isServer ? SERVER_CIPHER_LIST : CLIENT_CIPHER_LIST)) { SSL_free(result->ssl); tor_free(result); return NULL; } result->socket = sock; #ifdef USE_BSOCKETS bio = BIO_new_bsocket(sock, BIO_NOCLOSE); #else bio = BIO_new_socket(sock, BIO_NOCLOSE); #endif if (! bio) { tls_log_errors(NULL, LOG_WARN, "opening BIO"); SSL_free(result->ssl); tor_free(result); return NULL; } HT_INSERT(tlsmap, &tlsmap_root, result); SSL_set_bio(result->ssl, bio, bio); tor_tls_context_incref(global_tls_context); result->context = global_tls_context; result->state = TOR_TLS_ST_HANDSHAKE; result->isServer = isServer; result->wantwrite_n = 0; result->last_write_count = BIO_number_written(bio); result->last_read_count = 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); } #ifdef V2_HANDSHAKE_SERVER if (isServer) { SSL_set_info_callback(result->ssl, tor_tls_server_info_callback); } #endif /* Not expected to get called. */ tls_log_errors(NULL, LOG_WARN, "generating TLS context"); return result; } /** Make future log messages about tls display the address * address. */ void tor_tls_set_logged_address(tor_tls_t *tls, const char *address) { tor_assert(tls); tor_free(tls->address); tls->address = tor_strdup(address); } /** 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 untile 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; #ifdef V2_HANDSHAKE_SERVER if (cb) { SSL_set_info_callback(tls->ssl, tor_tls_server_info_callback); } else { SSL_set_info_callback(tls->ssl, NULL); } #endif } /** Return whether this tls initiated the connect (client) or * received it (server). */ int tor_tls_is_server(tor_tls_t *tls) { tor_assert(tls); return tls->isServer; } /** Release resources associated with a TLS object. Does not close the * underlying file descriptor. */ void tor_tls_free(tor_tls_t *tls) { tor_tls_t *removed; tor_assert(tls && tls->ssl); removed = HT_REMOVE(tlsmap, &tlsmap_root, tls); if (!removed) { log_warn(LD_BUG, "Freeing a TLS that was not in the ssl->tls map."); } SSL_free(tls->ssl); tls->ssl = NULL; tls->negotiated_callback = NULL; if (tls->context) tor_tls_context_decref(tls->context); tor_free(tls->address); tor_free(tls); } /** 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. */ 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) { #ifdef V2_HANDSHAKE_SERVER 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; } #endif return r; } err = tor_tls_get_error(tls, r, CATCH_ZERO, "reading", LOG_DEBUG); 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; } } /** 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); if (err == TOR_TLS_DONE) { 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(); if (tls->isServer) { r = SSL_accept(tls->ssl); } else { r = SSL_connect(tls->ssl); } r = tor_tls_get_error(tls,r,0, "handshaking", LOG_INFO); if (ERR_peek_error() != 0) { tls_log_errors(tls, tls->isServer ? LOG_INFO : LOG_WARN, "handshaking"); return TOR_TLS_ERROR_MISC; } if (r == TOR_TLS_DONE) { tls->state = TOR_TLS_ST_OPEN; if (tls->isServer) { SSL_set_info_callback(tls->ssl, NULL); SSL_set_verify(tls->ssl, SSL_VERIFY_PEER, always_accept_verify_cb); /* There doesn't seem to be a clear OpenSSL API to clear mode flags. */ tls->ssl->mode &= ~SSL_MODE_NO_AUTO_CHAIN; #ifdef V2_HANDSHAKE_SERVER if (tor_tls_client_is_using_v2_ciphers(tls->ssl, ADDR(tls))) { /* 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_NET, "Completed V2 TLS handshake with client; waiting " "for renegotiation."); } else { tls->wasV2Handshake = 0; } #endif } else { #ifdef V2_HANDSHAKE_CLIENT /* If we got no ID cert, we're a v2 handshake. */ X509 *cert = SSL_get_peer_certificate(tls->ssl); STACK_OF(X509) *chain = SSL_get_peer_cert_chain(tls->ssl); int n_certs = sk_X509_num(chain); if (n_certs > 1 || (n_certs == 1 && cert != sk_X509_value(chain, 0))) tls->wasV2Handshake = 0; else { log_debug(LD_NET, "Server sent back a single certificate; looks like " "a v2 handshake on %p.", tls); tls->wasV2Handshake = 1; } if (cert) X509_free(cert); #endif SSL_set_cipher_list(tls->ssl, SERVER_CIPHER_LIST); } } return r; } /** Client only: Renegotiate a TLS session. When finished, returns * TOR_TLS_DONE. On failure, returns TOR_TLS_ERROR, TOR_TLS_WANTREAD, or * TOR_TLS_WANTWRITE. */ int tor_tls_renegotiate(tor_tls_t *tls) { int r; tor_assert(tls); /* We could do server-initiated renegotiation too, but that would be tricky. * Instead of "SSL_renegotiate, then SSL_do_handshake until done" */ tor_assert(!tls->isServer); if (tls->state != TOR_TLS_ST_RENEGOTIATE) { int r = SSL_renegotiate(tls->ssl); if (r <= 0) { return tor_tls_get_error(tls, r, CATCH_SYSCALL|CATCH_ZERO, "renegotiating", LOG_WARN); } tls->state = TOR_TLS_ST_RENEGOTIATE; } r = SSL_do_handshake(tls->ssl); if (r == 1) { tls->state = TOR_TLS_ST_OPEN; return TOR_TLS_DONE; } else return tor_tls_get_error(tls, r, CATCH_SYSCALL|CATCH_ZERO, "renegotiating handshake", LOG_WARN); } /** Shut down an open tls connection tls. When finished, returns * TOR_TLS_DONE. On failure, returns TOR_TLS_ERROR, TOR_TLS_WANTREAD, * or TOR_TLS_WANTWRITE. */ int tor_tls_shutdown(tor_tls_t *tls) { int r, err; char buf[128]; tor_assert(tls); tor_assert(tls->ssl); while (1) { if (tls->state == TOR_TLS_ST_SENTCLOSE) { /* If we've already called shutdown once to send a close message, * we read until the other side has closed too. */ do { r = SSL_read(tls->ssl, buf, 128); } while (r>0); err = tor_tls_get_error(tls, r, CATCH_ZERO, "reading to shut down", LOG_INFO); if (err == _TOR_TLS_ZERORETURN) { tls->state = TOR_TLS_ST_GOTCLOSE; /* fall through... */ } else { return err; } } r = SSL_shutdown(tls->ssl); if (r == 1) { /* If shutdown returns 1, the connection is entirely closed. */ tls->state = TOR_TLS_ST_CLOSED; return TOR_TLS_DONE; } err = tor_tls_get_error(tls, r, CATCH_SYSCALL|CATCH_ZERO, "shutting down", LOG_INFO); if (err == _TOR_TLS_SYSCALL) { /* The underlying TCP connection closed while we were shutting down. */ tls->state = TOR_TLS_ST_CLOSED; return TOR_TLS_DONE; } else if (err == _TOR_TLS_ZERORETURN) { /* The TLS connection says that it sent a shutdown record, but * isn't done shutting down yet. Make sure that this hasn't * happened before, then go back to the start of the function * and try to read. */ if (tls->state == TOR_TLS_ST_GOTCLOSE || tls->state == TOR_TLS_ST_SENTCLOSE) { log(LOG_WARN, LD_NET, "TLS returned \"half-closed\" value while already half-closed"); return TOR_TLS_ERROR_MISC; } tls->state = TOR_TLS_ST_SENTCLOSE; /* fall through ... */ } else { return err; } } /* end loop */ } /** 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, "getting peer certificate"); if (!cert) return 0; X509_free(cert); return 1; } /** Warn that a certificate lifetime extends through a certain range. */ static void log_cert_lifetime(X509 *cert, const char *problem) { BIO *bio = NULL; BUF_MEM *buf; char *s1=NULL, *s2=NULL; char mytime[33]; time_t now = time(NULL); struct tm tm; if (problem) log_warn(LD_GENERAL, "Certificate %s: is your system clock set incorrectly?", problem); if (!(bio = BIO_new(BIO_s_mem()))) { log_warn(LD_GENERAL, "Couldn't allocate BIO!"); goto end; } if (!(ASN1_TIME_print(bio, X509_get_notBefore(cert)))) { tls_log_errors(NULL, LOG_WARN, "printing certificate lifetime"); goto end; } BIO_get_mem_ptr(bio, &buf); s1 = tor_strndup(buf->data, buf->length); (void)BIO_reset(bio); if (!(ASN1_TIME_print(bio, X509_get_notAfter(cert)))) { tls_log_errors(NULL, LOG_WARN, "printing certificate lifetime"); goto end; } BIO_get_mem_ptr(bio, &buf); s2 = tor_strndup(buf->data, buf->length); strftime(mytime, 32, "%b %d %H:%M:%S %Y GMT", tor_gmtime_r(&now, &tm)); log_warn(LD_GENERAL, "(certificate lifetime runs from %s through %s. Your time is %s.)", s1,s2,mytime); end: /* Not expected to get invoked */ tls_log_errors(NULL, LOG_WARN, "getting certificate lifetime"); if (bio) BIO_free(bio); if (s1) tor_free(s1); if (s2) tor_free(s2); } /** 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 to cert_out, so it needs to be * freed. id_cert_out doesn't. */ static 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; iidentity_key to the identity certificate's key and return * 0. Else, return -1 and log complaints with log-level severity. */ int tor_tls_verify(int severity, tor_tls_t *tls, crypto_pk_env_t **identity_key) { X509 *cert = NULL, *id_cert = NULL; EVP_PKEY *id_pkey = NULL; RSA *rsa; int r = -1; *identity_key = NULL; try_to_extract_certs_from_tls(severity, tls, &cert, &id_cert); if (!cert) goto done; if (!id_cert) { log_fn(severity,LD_PROTOCOL,"No distinct identity certificate found"); goto done; } if (!(id_pkey = X509_get_pubkey(id_cert)) || X509_verify(cert, id_pkey) <= 0) { log_fn(severity,LD_PROTOCOL,"X509_verify on cert and pkey returned <= 0"); tls_log_errors(tls, severity,"verifying certificate"); goto done; } rsa = EVP_PKEY_get1_RSA(id_pkey); if (!rsa) goto done; *identity_key = _crypto_new_pk_env_rsa(rsa); r = 0; done: if (cert) X509_free(cert); if (id_pkey) EVP_PKEY_free(id_pkey); /* This should never get invoked, but let's make sure in case OpenSSL * acts unexpectedly. */ tls_log_errors(tls, LOG_WARN, "finishing tor_tls_verify"); return r; } /** Check whether the certificate set on the connection tls is * expired or not-yet-valid, give or take tolerance * seconds. Return 0 for valid, -1 for failure. * * NOTE: you should call tor_tls_verify before tor_tls_check_lifetime. */ int tor_tls_check_lifetime(tor_tls_t *tls, int tolerance) { time_t now, t; X509 *cert; int r = -1; now = time(NULL); if (!(cert = SSL_get_peer_certificate(tls->ssl))) goto done; t = now + tolerance; if (X509_cmp_time(X509_get_notBefore(cert), &t) > 0) { log_cert_lifetime(cert, "not yet valid"); goto done; } t = now - tolerance; if (X509_cmp_time(X509_get_notAfter(cert), &t) < 0) { log_cert_lifetime(cert, "already expired"); goto done; } r = 0; done: if (cert) X509_free(cert); /* Not expected to get invoked */ tls_log_errors(tls, LOG_WARN, "checking certificate lifetime"); return r; } /** Return the number of bytes available for reading from tls. */ 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 = 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 (wbio->method == BIO_f_buffer() && (tmpbio = BIO_next(wbio)) != NULL) wbio = tmpbio; w = 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); } tls->last_read_count = r; tls->last_write_count = w; } /** 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(LOG_WARN, LD_CRYPTO, "Unhandled OpenSSL errors found at %s:%d: ", tor_fix_source_file(fname), line); tls_log_errors(NULL, LOG_WARN, 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) { if (tls->isServer) { #ifdef V2_HANDSHAKE_SERVER return ! tls->wasV2Handshake; #endif } else { #ifdef V2_HANDSHAKE_CLIENT return ! tls->wasV2Handshake; #endif } return 1; }