/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) * All rights reserved. * * This package is an SSL implementation written * by Eric Young (eay@cryptsoft.com). * The implementation was written so as to conform with Netscapes SSL. * * This library is free for commercial and non-commercial use as long as * the following conditions are aheared to. The following conditions * apply to all code found in this distribution, be it the RC4, RSA, * lhash, DES, etc., code; not just the SSL code. The SSL documentation * included with this distribution is covered by the same copyright terms * except that the holder is Tim Hudson (tjh@cryptsoft.com). * * Copyright remains Eric Young's, and as such any Copyright notices in * the code are not to be removed. * If this package is used in a product, Eric Young should be given attribution * as the author of the parts of the library used. * This can be in the form of a textual message at program startup or * in documentation (online or textual) provided with the package. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * "This product includes cryptographic software written by * Eric Young (eay@cryptsoft.com)" * The word 'cryptographic' can be left out if the rouines from the library * being used are not cryptographic related :-). * 4. If you include any Windows specific code (or a derivative thereof) from * the apps directory (application code) you must include an acknowledgement: * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" * * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * The licence and distribution terms for any publically available version or * derivative of this code cannot be changed. i.e. this code cannot simply be * copied and put under another distribution licence * [including the GNU Public Licence.] */ /* ==================================================================== * Copyright (c) 1998-2007 The OpenSSL Project. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * * 3. All advertising materials mentioning features or use of this * software must display the following acknowledgment: * "This product includes software developed by the OpenSSL Project * for use in the OpenSSL Toolkit. (http://www.openssl.org/)" * * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to * endorse or promote products derived from this software without * prior written permission. For written permission, please contact * openssl-core@openssl.org. * * 5. Products derived from this software may not be called "OpenSSL" * nor may "OpenSSL" appear in their names without prior written * permission of the OpenSSL Project. * * 6. Redistributions of any form whatsoever must retain the following * acknowledgment: * "This product includes software developed by the OpenSSL Project * for use in the OpenSSL Toolkit (http://www.openssl.org/)" * * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED * OF THE POSSIBILITY OF SUCH DAMAGE. * ==================================================================== * * This product includes cryptographic software written by Eric Young * (eay@cryptsoft.com). This product includes software written by Tim * Hudson (tjh@cryptsoft.com). */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "internal.h" static int ssl_check_clienthello_tlsext(SSL *s); static int ssl_check_serverhello_tlsext(SSL *s); const SSL3_ENC_METHOD TLSv1_enc_data = { tls1_prf, tls1_setup_key_block, tls1_generate_master_secret, tls1_change_cipher_state, tls1_final_finish_mac, tls1_cert_verify_mac, TLS_MD_CLIENT_FINISH_CONST,TLS_MD_CLIENT_FINISH_CONST_SIZE, TLS_MD_SERVER_FINISH_CONST,TLS_MD_SERVER_FINISH_CONST_SIZE, tls1_alert_code, tls1_export_keying_material, 0, }; const SSL3_ENC_METHOD TLSv1_1_enc_data = { tls1_prf, tls1_setup_key_block, tls1_generate_master_secret, tls1_change_cipher_state, tls1_final_finish_mac, tls1_cert_verify_mac, TLS_MD_CLIENT_FINISH_CONST,TLS_MD_CLIENT_FINISH_CONST_SIZE, TLS_MD_SERVER_FINISH_CONST,TLS_MD_SERVER_FINISH_CONST_SIZE, tls1_alert_code, tls1_export_keying_material, SSL_ENC_FLAG_EXPLICIT_IV, }; const SSL3_ENC_METHOD TLSv1_2_enc_data = { tls1_prf, tls1_setup_key_block, tls1_generate_master_secret, tls1_change_cipher_state, tls1_final_finish_mac, tls1_cert_verify_mac, TLS_MD_CLIENT_FINISH_CONST,TLS_MD_CLIENT_FINISH_CONST_SIZE, TLS_MD_SERVER_FINISH_CONST,TLS_MD_SERVER_FINISH_CONST_SIZE, tls1_alert_code, tls1_export_keying_material, SSL_ENC_FLAG_EXPLICIT_IV|SSL_ENC_FLAG_SIGALGS|SSL_ENC_FLAG_SHA256_PRF |SSL_ENC_FLAG_TLS1_2_CIPHERS, }; static int compare_uint16_t(const void *p1, const void *p2) { uint16_t u1 = *((const uint16_t *)p1); uint16_t u2 = *((const uint16_t *)p2); if (u1 < u2) { return -1; } else if (u1 > u2) { return 1; } else { return 0; } } /* Per http://tools.ietf.org/html/rfc5246#section-7.4.1.4, there may not be * more than one extension of the same type in a ClientHello or ServerHello. * This function does an initial scan over the extensions block to filter those * out. */ static int tls1_check_duplicate_extensions(const CBS *cbs) { CBS extensions = *cbs; size_t num_extensions = 0, i = 0; uint16_t *extension_types = NULL; int ret = 0; /* First pass: count the extensions. */ while (CBS_len(&extensions) > 0) { uint16_t type; CBS extension; if (!CBS_get_u16(&extensions, &type) || !CBS_get_u16_length_prefixed(&extensions, &extension)) { goto done; } num_extensions++; } if (num_extensions == 0) { return 1; } extension_types = (uint16_t *)OPENSSL_malloc(sizeof(uint16_t) * num_extensions); if (extension_types == NULL) { OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE); goto done; } /* Second pass: gather the extension types. */ extensions = *cbs; for (i = 0; i < num_extensions; i++) { CBS extension; if (!CBS_get_u16(&extensions, &extension_types[i]) || !CBS_get_u16_length_prefixed(&extensions, &extension)) { /* This should not happen. */ goto done; } } assert(CBS_len(&extensions) == 0); /* Sort the extensions and make sure there are no duplicates. */ qsort(extension_types, num_extensions, sizeof(uint16_t), compare_uint16_t); for (i = 1; i < num_extensions; i++) { if (extension_types[i - 1] == extension_types[i]) { goto done; } } ret = 1; done: OPENSSL_free(extension_types); return ret; } char ssl_early_callback_init(struct ssl_early_callback_ctx *ctx) { CBS client_hello, session_id, cipher_suites, compression_methods, extensions; CBS_init(&client_hello, ctx->client_hello, ctx->client_hello_len); if (/* Skip client version. */ !CBS_skip(&client_hello, 2) || /* Skip client nonce. */ !CBS_skip(&client_hello, 32) || /* Extract session_id. */ !CBS_get_u8_length_prefixed(&client_hello, &session_id)) { return 0; } ctx->session_id = CBS_data(&session_id); ctx->session_id_len = CBS_len(&session_id); /* Skip past DTLS cookie */ if (SSL_IS_DTLS(ctx->ssl)) { CBS cookie; if (!CBS_get_u8_length_prefixed(&client_hello, &cookie)) { return 0; } } /* Extract cipher_suites. */ if (!CBS_get_u16_length_prefixed(&client_hello, &cipher_suites) || CBS_len(&cipher_suites) < 2 || (CBS_len(&cipher_suites) & 1) != 0) { return 0; } ctx->cipher_suites = CBS_data(&cipher_suites); ctx->cipher_suites_len = CBS_len(&cipher_suites); /* Extract compression_methods. */ if (!CBS_get_u8_length_prefixed(&client_hello, &compression_methods) || CBS_len(&compression_methods) < 1) { return 0; } ctx->compression_methods = CBS_data(&compression_methods); ctx->compression_methods_len = CBS_len(&compression_methods); /* If the ClientHello ends here then it's valid, but doesn't have any * extensions. (E.g. SSLv3.) */ if (CBS_len(&client_hello) == 0) { ctx->extensions = NULL; ctx->extensions_len = 0; return 1; } /* Extract extensions and check it is valid. */ if (!CBS_get_u16_length_prefixed(&client_hello, &extensions) || !tls1_check_duplicate_extensions(&extensions) || CBS_len(&client_hello) != 0) { return 0; } ctx->extensions = CBS_data(&extensions); ctx->extensions_len = CBS_len(&extensions); return 1; } char SSL_early_callback_ctx_extension_get( const struct ssl_early_callback_ctx *ctx, uint16_t extension_type, const uint8_t **out_data, size_t *out_len) { CBS extensions; CBS_init(&extensions, ctx->extensions, ctx->extensions_len); while (CBS_len(&extensions) != 0) { uint16_t type; CBS extension; /* Decode the next extension. */ if (!CBS_get_u16(&extensions, &type) || !CBS_get_u16_length_prefixed(&extensions, &extension)) { return 0; } if (type == extension_type) { *out_data = CBS_data(&extension); *out_len = CBS_len(&extension); return 1; } } return 0; } struct tls_curve { uint16_t curve_id; int nid; const char curve_name[8]; }; /* ECC curves from RFC4492. */ static const struct tls_curve tls_curves[] = { {21, NID_secp224r1, "P-224"}, {23, NID_X9_62_prime256v1, "P-256"}, {24, NID_secp384r1, "P-384"}, {25, NID_secp521r1, "P-521"}, }; static const uint16_t eccurves_default[] = { 23, /* X9_62_prime256v1 */ 24, /* secp384r1 */ #if defined(BORINGSSL_ANDROID_SYSTEM) 25, /* secp521r1 */ #endif }; int tls1_ec_curve_id2nid(uint16_t curve_id) { size_t i; for (i = 0; i < sizeof(tls_curves) / sizeof(tls_curves[0]); i++) { if (curve_id == tls_curves[i].curve_id) { return tls_curves[i].nid; } } return NID_undef; } int tls1_ec_nid2curve_id(uint16_t *out_curve_id, int nid) { size_t i; for (i = 0; i < sizeof(tls_curves) / sizeof(tls_curves[0]); i++) { if (nid == tls_curves[i].nid) { *out_curve_id = tls_curves[i].curve_id; return 1; } } return 0; } const char* tls1_ec_curve_id2name(uint16_t curve_id) { size_t i; for (i = 0; i < sizeof(tls_curves) / sizeof(tls_curves[0]); i++) { if (curve_id == tls_curves[i].curve_id) { return tls_curves[i].curve_name; } } return NULL; } /* tls1_get_curvelist sets |*out_curve_ids| and |*out_curve_ids_len| to the * list of allowed curve IDs. If |get_peer_curves| is non-zero, return the * peer's curve list. Otherwise, return the preferred list. */ static void tls1_get_curvelist(SSL *s, int get_peer_curves, const uint16_t **out_curve_ids, size_t *out_curve_ids_len) { if (get_peer_curves) { /* Only clients send a curve list, so this function is only called * on the server. */ assert(s->server); *out_curve_ids = s->s3->tmp.peer_ellipticcurvelist; *out_curve_ids_len = s->s3->tmp.peer_ellipticcurvelist_length; return; } *out_curve_ids = s->tlsext_ellipticcurvelist; *out_curve_ids_len = s->tlsext_ellipticcurvelist_length; if (!*out_curve_ids) { *out_curve_ids = eccurves_default; *out_curve_ids_len = sizeof(eccurves_default) / sizeof(eccurves_default[0]); } } int tls1_check_curve(SSL *s, CBS *cbs, uint16_t *out_curve_id) { uint8_t curve_type; uint16_t curve_id; const uint16_t *curves; size_t curves_len, i; /* Only support named curves. */ if (!CBS_get_u8(cbs, &curve_type) || curve_type != NAMED_CURVE_TYPE || !CBS_get_u16(cbs, &curve_id)) { return 0; } tls1_get_curvelist(s, 0, &curves, &curves_len); for (i = 0; i < curves_len; i++) { if (curve_id == curves[i]) { *out_curve_id = curve_id; return 1; } } return 0; } int tls1_get_shared_curve(SSL *s) { const uint16_t *curves, *peer_curves, *pref, *supp; size_t curves_len, peer_curves_len, pref_len, supp_len, i, j; /* Can't do anything on client side */ if (s->server == 0) { return NID_undef; } tls1_get_curvelist(s, 0 /* local curves */, &curves, &curves_len); tls1_get_curvelist(s, 1 /* peer curves */, &peer_curves, &peer_curves_len); if (peer_curves_len == 0) { /* Clients are not required to send a supported_curves extension. In this * case, the server is free to pick any curve it likes. See RFC 4492, * section 4, paragraph 3. */ return (curves_len == 0) ? NID_undef : tls1_ec_curve_id2nid(curves[0]); } if (s->options & SSL_OP_CIPHER_SERVER_PREFERENCE) { pref = curves; pref_len = curves_len; supp = peer_curves; supp_len = peer_curves_len; } else { pref = peer_curves; pref_len = peer_curves_len; supp = curves; supp_len = curves_len; } for (i = 0; i < pref_len; i++) { for (j = 0; j < supp_len; j++) { if (pref[i] == supp[j]) { return tls1_ec_curve_id2nid(pref[i]); } } } return NID_undef; } int tls1_set_curves(uint16_t **out_curve_ids, size_t *out_curve_ids_len, const int *curves, size_t ncurves) { uint16_t *curve_ids; size_t i; curve_ids = (uint16_t *)OPENSSL_malloc(ncurves * sizeof(uint16_t)); if (curve_ids == NULL) { return 0; } for (i = 0; i < ncurves; i++) { if (!tls1_ec_nid2curve_id(&curve_ids[i], curves[i])) { OPENSSL_free(curve_ids); return 0; } } OPENSSL_free(*out_curve_ids); *out_curve_ids = curve_ids; *out_curve_ids_len = ncurves; return 1; } /* tls1_curve_params_from_ec_key sets |*out_curve_id| and |*out_comp_id| to the * TLS curve ID and point format, respectively, for |ec|. It returns one on * success and zero on failure. */ static int tls1_curve_params_from_ec_key(uint16_t *out_curve_id, uint8_t *out_comp_id, EC_KEY *ec) { int nid; uint16_t id; const EC_GROUP *grp; if (ec == NULL) { return 0; } grp = EC_KEY_get0_group(ec); if (grp == NULL) { return 0; } /* Determine curve ID */ nid = EC_GROUP_get_curve_name(grp); if (!tls1_ec_nid2curve_id(&id, nid)) { return 0; } /* Set the named curve ID. Arbitrary explicit curves are not supported. */ *out_curve_id = id; if (out_comp_id) { if (EC_KEY_get0_public_key(ec) == NULL) { return 0; } if (EC_KEY_get_conv_form(ec) == POINT_CONVERSION_COMPRESSED) { *out_comp_id = TLSEXT_ECPOINTFORMAT_ansiX962_compressed_prime; } else { *out_comp_id = TLSEXT_ECPOINTFORMAT_uncompressed; } } return 1; } /* tls1_check_curve_id returns one if |curve_id| is consistent with both our * and the peer's curve preferences. Note: if called as the client, only our * preferences are checked; the peer (the server) does not send preferences. */ static int tls1_check_curve_id(SSL *s, uint16_t curve_id) { const uint16_t *curves; size_t curves_len, i, get_peer_curves; /* Check against our list, then the peer's list. */ for (get_peer_curves = 0; get_peer_curves <= 1; get_peer_curves++) { if (get_peer_curves && !s->server) { /* Servers do not present a preference list so, if we are a client, only * check our list. */ continue; } tls1_get_curvelist(s, get_peer_curves, &curves, &curves_len); if (get_peer_curves && curves_len == 0) { /* Clients are not required to send a supported_curves extension. In this * case, the server is free to pick any curve it likes. See RFC 4492, * section 4, paragraph 3. */ continue; } for (i = 0; i < curves_len; i++) { if (curves[i] == curve_id) { break; } } if (i == curves_len) { return 0; } } return 1; } int tls1_check_ec_cert(SSL *s, X509 *x) { int ret = 0; EVP_PKEY *pkey = X509_get_pubkey(x); uint16_t curve_id; uint8_t comp_id; if (!pkey || pkey->type != EVP_PKEY_EC || !tls1_curve_params_from_ec_key(&curve_id, &comp_id, pkey->pkey.ec) || !tls1_check_curve_id(s, curve_id) || comp_id != TLSEXT_ECPOINTFORMAT_uncompressed) { goto done; } ret = 1; done: EVP_PKEY_free(pkey); return ret; } int tls1_check_ec_tmp_key(SSL *s) { if (s->cert->ecdh_nid != NID_undef) { /* If the curve is preconfigured, ECDH is acceptable iff the peer supports * the curve. */ uint16_t curve_id; return tls1_ec_nid2curve_id(&curve_id, s->cert->ecdh_nid) && tls1_check_curve_id(s, curve_id); } if (s->cert->ecdh_tmp_cb != NULL) { /* Assume the callback will provide an acceptable curve. */ return 1; } /* Otherwise, the curve gets selected automatically. ECDH is acceptable iff * there is a shared curve. */ return tls1_get_shared_curve(s) != NID_undef; } /* List of supported signature algorithms and hashes. Should make this * customisable at some point, for now include everything we support. */ #define tlsext_sigalg_rsa(md) md, TLSEXT_signature_rsa, #define tlsext_sigalg_ecdsa(md) md, TLSEXT_signature_ecdsa, #define tlsext_sigalg(md) tlsext_sigalg_rsa(md) tlsext_sigalg_ecdsa(md) static const uint8_t tls12_sigalgs[] = { tlsext_sigalg(TLSEXT_hash_sha512) tlsext_sigalg(TLSEXT_hash_sha384) tlsext_sigalg(TLSEXT_hash_sha256) tlsext_sigalg(TLSEXT_hash_sha224) tlsext_sigalg(TLSEXT_hash_sha1) }; size_t tls12_get_psigalgs(SSL *s, const uint8_t **psigs) { *psigs = tls12_sigalgs; return sizeof(tls12_sigalgs); } /* tls12_check_peer_sigalg parses a SignatureAndHashAlgorithm out of |cbs|. It * checks it is consistent with |s|'s sent supported signature algorithms and, * if so, writes the relevant digest into |*out_md| and returns 1. Otherwise it * returns 0 and writes an alert into |*out_alert|. */ int tls12_check_peer_sigalg(const EVP_MD **out_md, int *out_alert, SSL *s, CBS *cbs, EVP_PKEY *pkey) { const uint8_t *sent_sigs; size_t sent_sigslen, i; int sigalg = tls12_get_sigid(pkey->type); uint8_t hash, signature; /* Should never happen */ if (sigalg == -1) { OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); *out_alert = SSL_AD_INTERNAL_ERROR; return 0; } if (!CBS_get_u8(cbs, &hash) || !CBS_get_u8(cbs, &signature)) { OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); *out_alert = SSL_AD_DECODE_ERROR; return 0; } /* Check key type is consistent with signature */ if (sigalg != signature) { OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_SIGNATURE_TYPE); *out_alert = SSL_AD_ILLEGAL_PARAMETER; return 0; } if (pkey->type == EVP_PKEY_EC) { uint16_t curve_id; uint8_t comp_id; /* Check compression and curve matches extensions */ if (!tls1_curve_params_from_ec_key(&curve_id, &comp_id, pkey->pkey.ec)) { *out_alert = SSL_AD_INTERNAL_ERROR; return 0; } if (s->server && (!tls1_check_curve_id(s, curve_id) || comp_id != TLSEXT_ECPOINTFORMAT_uncompressed)) { OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_CURVE); *out_alert = SSL_AD_ILLEGAL_PARAMETER; return 0; } } /* Check signature matches a type we sent */ sent_sigslen = tls12_get_psigalgs(s, &sent_sigs); for (i = 0; i < sent_sigslen; i += 2, sent_sigs += 2) { if (hash == sent_sigs[0] && signature == sent_sigs[1]) { break; } } /* Allow fallback to SHA-1. */ if (i == sent_sigslen && hash != TLSEXT_hash_sha1) { OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_SIGNATURE_TYPE); *out_alert = SSL_AD_ILLEGAL_PARAMETER; return 0; } *out_md = tls12_get_hash(hash); if (*out_md == NULL) { OPENSSL_PUT_ERROR(SSL, SSL_R_UNKNOWN_DIGEST); *out_alert = SSL_AD_ILLEGAL_PARAMETER; return 0; } return 1; } /* Get a mask of disabled algorithms: an algorithm is disabled if it isn't * supported or doesn't appear in supported signature algorithms. Unlike * ssl_cipher_get_disabled this applies to a specific session and not global * settings. */ void ssl_set_client_disabled(SSL *s) { CERT *c = s->cert; const uint8_t *sigalgs; size_t i, sigalgslen; int have_rsa = 0, have_ecdsa = 0; c->mask_a = 0; c->mask_k = 0; /* Don't allow TLS 1.2 only ciphers if we don't suppport them */ if (!SSL_CLIENT_USE_TLS1_2_CIPHERS(s)) { c->mask_ssl = SSL_TLSV1_2; } else { c->mask_ssl = 0; } /* Now go through all signature algorithms seeing if we support any for RSA, * DSA, ECDSA. Do this for all versions not just TLS 1.2. */ sigalgslen = tls12_get_psigalgs(s, &sigalgs); for (i = 0; i < sigalgslen; i += 2, sigalgs += 2) { switch (sigalgs[1]) { case TLSEXT_signature_rsa: have_rsa = 1; break; case TLSEXT_signature_ecdsa: have_ecdsa = 1; break; } } /* Disable auth if we don't include any appropriate signature algorithms. */ if (!have_rsa) { c->mask_a |= SSL_aRSA; } if (!have_ecdsa) { c->mask_a |= SSL_aECDSA; } /* with PSK there must be client callback set */ if (!s->psk_client_callback) { c->mask_a |= SSL_aPSK; c->mask_k |= SSL_kPSK; } } /* tls_extension represents a TLS extension that is handled internally. The * |init| function is called for each handshake, before any other functions of * the extension. Then the add and parse callbacks are called as needed. * * The parse callbacks receive a |CBS| that contains the contents of the * extension (i.e. not including the type and length bytes). If an extension is * not received then the parse callbacks will be called with a NULL CBS so that * they can do any processing needed to handle the absence of an extension. * * The add callbacks receive a |CBB| to which the extension can be appended but * the function is responsible for appending the type and length bytes too. * * All callbacks return one for success and zero for error. If a parse function * returns zero then a fatal alert with value |*out_alert| will be sent. If * |*out_alert| isn't set, then a |decode_error| alert will be sent. */ struct tls_extension { uint16_t value; void (*init)(SSL *ssl); int (*add_clienthello)(SSL *ssl, CBB *out); int (*parse_serverhello)(SSL *ssl, uint8_t *out_alert, CBS *contents); int (*parse_clienthello)(SSL *ssl, uint8_t *out_alert, CBS *contents); int (*add_serverhello)(SSL *ssl, CBB *out); }; /* Server name indication (SNI). * * https://tools.ietf.org/html/rfc6066#section-3. */ static void ext_sni_init(SSL *ssl) { ssl->s3->tmp.should_ack_sni = 0; } static int ext_sni_add_clienthello(SSL *ssl, CBB *out) { if (ssl->tlsext_hostname == NULL) { return 1; } CBB contents, server_name_list, name; if (!CBB_add_u16(out, TLSEXT_TYPE_server_name) || !CBB_add_u16_length_prefixed(out, &contents) || !CBB_add_u16_length_prefixed(&contents, &server_name_list) || !CBB_add_u8(&server_name_list, TLSEXT_NAMETYPE_host_name) || !CBB_add_u16_length_prefixed(&server_name_list, &name) || !CBB_add_bytes(&name, (const uint8_t *)ssl->tlsext_hostname, strlen(ssl->tlsext_hostname)) || !CBB_flush(out)) { return 0; } return 1; } static int ext_sni_parse_serverhello(SSL *ssl, uint8_t *out_alert, CBS *contents) { if (contents == NULL) { return 1; } if (CBS_len(contents) != 0) { return 0; } assert(ssl->tlsext_hostname != NULL); if (!ssl->hit) { assert(ssl->session->tlsext_hostname == NULL); ssl->session->tlsext_hostname = BUF_strdup(ssl->tlsext_hostname); if (!ssl->session->tlsext_hostname) { *out_alert = SSL_AD_INTERNAL_ERROR; return 0; } } return 1; } static int ext_sni_parse_clienthello(SSL *ssl, uint8_t *out_alert, CBS *contents) { if (contents == NULL) { return 1; } /* The servername extension is treated as follows: * * - Only the hostname type is supported with a maximum length of 255. * - The servername is rejected if too long or if it contains zeros, in * which case an fatal alert is generated. * - The servername field is maintained together with the session cache. * - When a session is resumed, the servername callback is invoked in order * to allow the application to position itself to the right context. * - The servername is acknowledged if it is new for a session or when * it is identical to a previously used for the same session. * Applications can control the behaviour. They can at any time * set a 'desirable' servername for a new SSL object. This can be the * case for example with HTTPS when a Host: header field is received and * a renegotiation is requested. In this case, a possible servername * presented in the new client hello is only acknowledged if it matches * the value of the Host: field. * - Applications must use SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION * if they provide for changing an explicit servername context for the * session, * i.e. when the session has been established with a servername extension. */ CBS server_name_list; char have_seen_host_name = 0; if (!CBS_get_u16_length_prefixed(contents, &server_name_list) || CBS_len(&server_name_list) == 0 || CBS_len(contents) != 0) { return 0; } /* Decode each ServerName in the extension. */ while (CBS_len(&server_name_list) > 0) { uint8_t name_type; CBS host_name; if (!CBS_get_u8(&server_name_list, &name_type) || !CBS_get_u16_length_prefixed(&server_name_list, &host_name)) { return 0; } /* Only host_name is supported. */ if (name_type != TLSEXT_NAMETYPE_host_name) { continue; } if (have_seen_host_name) { /* The ServerNameList MUST NOT contain more than one name of the same * name_type. */ return 0; } have_seen_host_name = 1; if (CBS_len(&host_name) == 0 || CBS_len(&host_name) > TLSEXT_MAXLEN_host_name || CBS_contains_zero_byte(&host_name)) { *out_alert = SSL_AD_UNRECOGNIZED_NAME; return 0; } if (!ssl->hit) { assert(ssl->session->tlsext_hostname == NULL); if (ssl->session->tlsext_hostname) { /* This should be impossible. */ return 0; } /* Copy the hostname as a string. */ if (!CBS_strdup(&host_name, &ssl->session->tlsext_hostname)) { *out_alert = SSL_AD_INTERNAL_ERROR; return 0; } ssl->s3->tmp.should_ack_sni = 1; } } return 1; } static int ext_sni_add_serverhello(SSL *ssl, CBB *out) { if (ssl->hit || !ssl->s3->tmp.should_ack_sni || ssl->session->tlsext_hostname == NULL) { return 1; } if (!CBB_add_u16(out, TLSEXT_TYPE_server_name) || !CBB_add_u16(out, 0 /* length */)) { return 0; } return 1; } /* Renegotiation indication. * * https://tools.ietf.org/html/rfc5746 */ static int ext_ri_add_clienthello(SSL *ssl, CBB *out) { CBB contents, prev_finished; if (!CBB_add_u16(out, TLSEXT_TYPE_renegotiate) || !CBB_add_u16_length_prefixed(out, &contents) || !CBB_add_u8_length_prefixed(&contents, &prev_finished) || !CBB_add_bytes(&prev_finished, ssl->s3->previous_client_finished, ssl->s3->previous_client_finished_len) || !CBB_flush(out)) { return 0; } return 1; } static int ext_ri_parse_serverhello(SSL *ssl, uint8_t *out_alert, CBS *contents) { if (contents == NULL) { /* No renegotiation extension received. * * Strictly speaking if we want to avoid an attack we should *always* see * RI even on initial ServerHello because the client doesn't see any * renegotiation during an attack. However this would mean we could not * connect to any server which doesn't support RI. * * A lack of the extension is allowed if SSL_OP_LEGACY_SERVER_CONNECT is * defined. */ if (ssl->options & SSL_OP_LEGACY_SERVER_CONNECT) { return 1; } *out_alert = SSL_AD_HANDSHAKE_FAILURE; OPENSSL_PUT_ERROR(SSL, SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED); return 0; } const size_t expected_len = ssl->s3->previous_client_finished_len + ssl->s3->previous_server_finished_len; /* Check for logic errors */ assert(!expected_len || ssl->s3->previous_client_finished_len); assert(!expected_len || ssl->s3->previous_server_finished_len); /* Parse out the extension contents. */ CBS renegotiated_connection; if (!CBS_get_u8_length_prefixed(contents, &renegotiated_connection) || CBS_len(contents) != 0) { OPENSSL_PUT_ERROR(SSL, SSL_R_RENEGOTIATION_ENCODING_ERR); *out_alert = SSL_AD_ILLEGAL_PARAMETER; return 0; } /* Check that the extension matches. */ if (CBS_len(&renegotiated_connection) != expected_len) { OPENSSL_PUT_ERROR(SSL, SSL_R_RENEGOTIATION_MISMATCH); *out_alert = SSL_AD_HANDSHAKE_FAILURE; return 0; } const uint8_t *d = CBS_data(&renegotiated_connection); if (CRYPTO_memcmp(d, ssl->s3->previous_client_finished, ssl->s3->previous_client_finished_len)) { OPENSSL_PUT_ERROR(SSL, SSL_R_RENEGOTIATION_MISMATCH); *out_alert = SSL_AD_HANDSHAKE_FAILURE; return 0; } d += ssl->s3->previous_client_finished_len; if (CRYPTO_memcmp(d, ssl->s3->previous_server_finished, ssl->s3->previous_server_finished_len)) { OPENSSL_PUT_ERROR(SSL, SSL_R_RENEGOTIATION_MISMATCH); *out_alert = SSL_AD_ILLEGAL_PARAMETER; return 0; } ssl->s3->send_connection_binding = 1; return 1; } static int ext_ri_parse_clienthello(SSL *ssl, uint8_t *out_alert, CBS *contents) { /* Renegotiation isn't supported as a server so this function should never be * called after the initial handshake. */ assert(!ssl->s3->initial_handshake_complete); CBS fake_contents; static const uint8_t kFakeExtension[] = {0}; if (contents == NULL) { if (ssl->s3->send_connection_binding) { /* The renegotiation SCSV was received so pretend that we received a * renegotiation extension. */ CBS_init(&fake_contents, kFakeExtension, sizeof(kFakeExtension)); contents = &fake_contents; /* We require that the renegotiation extension is at index zero of * kExtensions. */ ssl->s3->tmp.extensions.received |= (1u << 0); } else { return 1; } } CBS renegotiated_connection; if (!CBS_get_u8_length_prefixed(contents, &renegotiated_connection) || CBS_len(contents) != 0) { OPENSSL_PUT_ERROR(SSL, SSL_R_RENEGOTIATION_ENCODING_ERR); return 0; } /* Check that the extension matches */ if (!CBS_mem_equal(&renegotiated_connection, ssl->s3->previous_client_finished, ssl->s3->previous_client_finished_len)) { OPENSSL_PUT_ERROR(SSL, SSL_R_RENEGOTIATION_MISMATCH); *out_alert = SSL_AD_HANDSHAKE_FAILURE; return 0; } ssl->s3->send_connection_binding = 1; return 1; } static int ext_ri_add_serverhello(SSL *ssl, CBB *out) { CBB contents, prev_finished; if (!CBB_add_u16(out, TLSEXT_TYPE_renegotiate) || !CBB_add_u16_length_prefixed(out, &contents) || !CBB_add_u8_length_prefixed(&contents, &prev_finished) || !CBB_add_bytes(&prev_finished, ssl->s3->previous_client_finished, ssl->s3->previous_client_finished_len) || !CBB_add_bytes(&prev_finished, ssl->s3->previous_server_finished, ssl->s3->previous_server_finished_len) || !CBB_flush(out)) { return 0; } return 1; } /* Extended Master Secret. * * https://tools.ietf.org/html/draft-ietf-tls-session-hash-05 */ static void ext_ems_init(SSL *ssl) { ssl->s3->tmp.extended_master_secret = 0; } static int ext_ems_add_clienthello(SSL *ssl, CBB *out) { if (ssl->version == SSL3_VERSION) { return 1; } if (!CBB_add_u16(out, TLSEXT_TYPE_extended_master_secret) || !CBB_add_u16(out, 0 /* length */)) { return 0; } return 1; } static int ext_ems_parse_serverhello(SSL *ssl, uint8_t *out_alert, CBS *contents) { if (contents == NULL) { return 1; } if (ssl->version == SSL3_VERSION || CBS_len(contents) != 0) { return 0; } ssl->s3->tmp.extended_master_secret = 1; return 1; } static int ext_ems_parse_clienthello(SSL *ssl, uint8_t *out_alert, CBS *contents) { if (ssl->version == SSL3_VERSION || contents == NULL) { return 1; } if (CBS_len(contents) != 0) { return 0; } ssl->s3->tmp.extended_master_secret = 1; return 1; } static int ext_ems_add_serverhello(SSL *ssl, CBB *out) { if (!ssl->s3->tmp.extended_master_secret) { return 1; } if (!CBB_add_u16(out, TLSEXT_TYPE_extended_master_secret) || !CBB_add_u16(out, 0 /* length */)) { return 0; } return 1; } /* Session tickets. * * https://tools.ietf.org/html/rfc5077 */ static int ext_ticket_add_clienthello(SSL *ssl, CBB *out) { if (SSL_get_options(ssl) & SSL_OP_NO_TICKET) { return 1; } const uint8_t *ticket_data = NULL; int ticket_len = 0; /* Renegotiation does not participate in session resumption. However, still * advertise the extension to avoid potentially breaking servers which carry * over the state from the previous handshake, such as OpenSSL servers * without upstream's 3c3f0259238594d77264a78944d409f2127642c4. */ if (!ssl->s3->initial_handshake_complete && ssl->session != NULL && ssl->session->tlsext_tick != NULL) { ticket_data = ssl->session->tlsext_tick; ticket_len = ssl->session->tlsext_ticklen; } CBB ticket; if (!CBB_add_u16(out, TLSEXT_TYPE_session_ticket) || !CBB_add_u16_length_prefixed(out, &ticket) || !CBB_add_bytes(&ticket, ticket_data, ticket_len) || !CBB_flush(out)) { return 0; } return 1; } static int ext_ticket_parse_serverhello(SSL *ssl, uint8_t *out_alert, CBS *contents) { ssl->tlsext_ticket_expected = 0; if (contents == NULL) { return 1; } /* If |SSL_OP_NO_TICKET| is set then no extension will have been sent and * this function should never be called, even if the server tries to send the * extension. */ assert((SSL_get_options(ssl) & SSL_OP_NO_TICKET) == 0); if (CBS_len(contents) != 0) { return 0; } ssl->tlsext_ticket_expected = 1; return 1; } static int ext_ticket_parse_clienthello(SSL *ssl, uint8_t *out_alert, CBS *contents) { /* This function isn't used because the ticket extension from the client is * handled in ssl_session.c. */ return 1; } static int ext_ticket_add_serverhello(SSL *ssl, CBB *out) { if (!ssl->tlsext_ticket_expected) { return 1; } /* If |SSL_OP_NO_TICKET| is set, |tlsext_ticket_expected| should never be * true. */ assert((SSL_get_options(ssl) & SSL_OP_NO_TICKET) == 0); if (!CBB_add_u16(out, TLSEXT_TYPE_session_ticket) || !CBB_add_u16(out, 0 /* length */)) { return 0; } return 1; } /* Signature Algorithms. * * https://tools.ietf.org/html/rfc5246#section-7.4.1.4.1 */ static int ext_sigalgs_add_clienthello(SSL *ssl, CBB *out) { if (ssl3_version_from_wire(ssl, ssl->client_version) < TLS1_2_VERSION) { return 1; } const uint8_t *sigalgs_data; const size_t sigalgs_len = tls12_get_psigalgs(ssl, &sigalgs_data); CBB contents, sigalgs; if (!CBB_add_u16(out, TLSEXT_TYPE_signature_algorithms) || !CBB_add_u16_length_prefixed(out, &contents) || !CBB_add_u16_length_prefixed(&contents, &sigalgs) || !CBB_add_bytes(&sigalgs, sigalgs_data, sigalgs_len) || !CBB_flush(out)) { return 0; } return 1; } static int ext_sigalgs_parse_serverhello(SSL *ssl, uint8_t *out_alert, CBS *contents) { if (contents != NULL) { /* Servers MUST NOT send this extension. */ *out_alert = SSL_AD_UNSUPPORTED_EXTENSION; OPENSSL_PUT_ERROR(SSL, SSL_R_SIGNATURE_ALGORITHMS_EXTENSION_SENT_BY_SERVER); return 0; } return 1; } static int ext_sigalgs_parse_clienthello(SSL *ssl, uint8_t *out_alert, CBS *contents) { OPENSSL_free(ssl->cert->peer_sigalgs); ssl->cert->peer_sigalgs = NULL; ssl->cert->peer_sigalgslen = 0; if (contents == NULL) { return 1; } CBS supported_signature_algorithms; if (!CBS_get_u16_length_prefixed(contents, &supported_signature_algorithms) || CBS_len(contents) != 0 || CBS_len(&supported_signature_algorithms) == 0 || !tls1_parse_peer_sigalgs(ssl, &supported_signature_algorithms)) { return 0; } return 1; } static int ext_sigalgs_add_serverhello(SSL *ssl, CBB *out) { /* Servers MUST NOT send this extension. */ return 1; } /* OCSP Stapling. * * https://tools.ietf.org/html/rfc6066#section-8 */ static void ext_ocsp_init(SSL *ssl) { ssl->s3->tmp.certificate_status_expected = 0; } static int ext_ocsp_add_clienthello(SSL *ssl, CBB *out) { if (!ssl->ocsp_stapling_enabled) { return 1; } CBB contents; if (!CBB_add_u16(out, TLSEXT_TYPE_status_request) || !CBB_add_u16_length_prefixed(out, &contents) || !CBB_add_u8(&contents, TLSEXT_STATUSTYPE_ocsp) || !CBB_add_u16(&contents, 0 /* empty responder ID list */) || !CBB_add_u16(&contents, 0 /* empty request extensions */) || !CBB_flush(out)) { return 0; } return 1; } static int ext_ocsp_parse_serverhello(SSL *ssl, uint8_t *out_alert, CBS *contents) { if (contents == NULL) { return 1; } if (CBS_len(contents) != 0) { return 0; } ssl->s3->tmp.certificate_status_expected = 1; return 1; } static int ext_ocsp_parse_clienthello(SSL *ssl, uint8_t *out_alert, CBS *contents) { if (contents == NULL) { return 1; } uint8_t status_type; if (!CBS_get_u8(contents, &status_type)) { return 0; } /* We cannot decide whether OCSP stapling will occur yet because the correct * SSL_CTX might not have been selected. */ ssl->s3->tmp.ocsp_stapling_requested = status_type == TLSEXT_STATUSTYPE_ocsp; return 1; } static int ext_ocsp_add_serverhello(SSL *ssl, CBB *out) { /* The extension shouldn't be sent when resuming sessions. */ if (ssl->hit || !ssl->s3->tmp.ocsp_stapling_requested || ssl->ctx->ocsp_response_length == 0) { return 1; } ssl->s3->tmp.certificate_status_expected = 1; return CBB_add_u16(out, TLSEXT_TYPE_status_request) && CBB_add_u16(out, 0 /* length */); } /* Next protocol negotiation. * * https://htmlpreview.github.io/?https://github.com/agl/technotes/blob/master/nextprotoneg.html */ static void ext_npn_init(SSL *ssl) { ssl->s3->next_proto_neg_seen = 0; } static int ext_npn_add_clienthello(SSL *ssl, CBB *out) { if (ssl->s3->initial_handshake_complete || ssl->ctx->next_proto_select_cb == NULL || SSL_IS_DTLS(ssl)) { return 1; } if (!CBB_add_u16(out, TLSEXT_TYPE_next_proto_neg) || !CBB_add_u16(out, 0 /* length */)) { return 0; } return 1; } static int ext_npn_parse_serverhello(SSL *ssl, uint8_t *out_alert, CBS *contents) { if (contents == NULL) { return 1; } /* If any of these are false then we should never have sent the NPN * extension in the ClientHello and thus this function should never have been * called. */ assert(!ssl->s3->initial_handshake_complete); assert(!SSL_IS_DTLS(ssl)); assert(ssl->ctx->next_proto_select_cb != NULL); if (ssl->s3->alpn_selected != NULL) { /* NPN and ALPN may not be negotiated in the same connection. */ *out_alert = SSL_AD_ILLEGAL_PARAMETER; OPENSSL_PUT_ERROR(SSL, SSL_R_NEGOTIATED_BOTH_NPN_AND_ALPN); return 0; } const uint8_t *const orig_contents = CBS_data(contents); const size_t orig_len = CBS_len(contents); while (CBS_len(contents) != 0) { CBS proto; if (!CBS_get_u8_length_prefixed(contents, &proto) || CBS_len(&proto) == 0) { return 0; } } uint8_t *selected; uint8_t selected_len; if (ssl->ctx->next_proto_select_cb( ssl, &selected, &selected_len, orig_contents, orig_len, ssl->ctx->next_proto_select_cb_arg) != SSL_TLSEXT_ERR_OK) { *out_alert = SSL_AD_INTERNAL_ERROR; return 0; } OPENSSL_free(ssl->next_proto_negotiated); ssl->next_proto_negotiated = BUF_memdup(selected, selected_len); if (ssl->next_proto_negotiated == NULL) { *out_alert = SSL_AD_INTERNAL_ERROR; return 0; } ssl->next_proto_negotiated_len = selected_len; ssl->s3->next_proto_neg_seen = 1; return 1; } static int ext_npn_parse_clienthello(SSL *ssl, uint8_t *out_alert, CBS *contents) { if (contents != NULL && CBS_len(contents) != 0) { return 0; } if (contents == NULL || ssl->s3->initial_handshake_complete || /* If the ALPN extension is seen before NPN, ignore it. (If ALPN is seen * afterwards, parsing the ALPN extension will clear * |next_proto_neg_seen|. */ ssl->s3->alpn_selected != NULL || ssl->ctx->next_protos_advertised_cb == NULL || SSL_IS_DTLS(ssl)) { return 1; } ssl->s3->next_proto_neg_seen = 1; return 1; } static int ext_npn_add_serverhello(SSL *ssl, CBB *out) { /* |next_proto_neg_seen| might have been cleared when an ALPN extension was * parsed. */ if (!ssl->s3->next_proto_neg_seen) { return 1; } const uint8_t *npa; unsigned npa_len; if (ssl->ctx->next_protos_advertised_cb( ssl, &npa, &npa_len, ssl->ctx->next_protos_advertised_cb_arg) != SSL_TLSEXT_ERR_OK) { ssl->s3->next_proto_neg_seen = 0; return 1; } CBB contents; if (!CBB_add_u16(out, TLSEXT_TYPE_next_proto_neg) || !CBB_add_u16_length_prefixed(out, &contents) || !CBB_add_bytes(&contents, npa, npa_len) || !CBB_flush(out)) { return 0; } return 1; } /* Signed certificate timestamps. * * https://tools.ietf.org/html/rfc6962#section-3.3.1 */ static int ext_sct_add_clienthello(SSL *ssl, CBB *out) { if (!ssl->signed_cert_timestamps_enabled) { return 1; } if (!CBB_add_u16(out, TLSEXT_TYPE_certificate_timestamp) || !CBB_add_u16(out, 0 /* length */)) { return 0; } return 1; } static int ext_sct_parse_serverhello(SSL *ssl, uint8_t *out_alert, CBS *contents) { if (contents == NULL) { return 1; } /* If this is false then we should never have sent the SCT extension in the * ClientHello and thus this function should never have been called. */ assert(ssl->signed_cert_timestamps_enabled); if (CBS_len(contents) == 0) { *out_alert = SSL_AD_DECODE_ERROR; return 0; } /* Session resumption uses the original session information. */ if (!ssl->hit && !CBS_stow(contents, &ssl->session->tlsext_signed_cert_timestamp_list, &ssl->session->tlsext_signed_cert_timestamp_list_length)) { *out_alert = SSL_AD_INTERNAL_ERROR; return 0; } return 1; } static int ext_sct_parse_clienthello(SSL *ssl, uint8_t *out_alert, CBS *contents) { return contents == NULL || CBS_len(contents) == 0; } static int ext_sct_add_serverhello(SSL *ssl, CBB *out) { /* The extension shouldn't be sent when resuming sessions. */ if (ssl->hit || ssl->ctx->signed_cert_timestamp_list_length == 0) { return 1; } CBB contents; return CBB_add_u16(out, TLSEXT_TYPE_certificate_timestamp) && CBB_add_u16_length_prefixed(out, &contents) && CBB_add_bytes(&contents, ssl->ctx->signed_cert_timestamp_list, ssl->ctx->signed_cert_timestamp_list_length) && CBB_flush(out); } /* Application-level Protocol Negotiation. * * https://tools.ietf.org/html/rfc7301 */ static void ext_alpn_init(SSL *ssl) { OPENSSL_free(ssl->s3->alpn_selected); ssl->s3->alpn_selected = NULL; } static int ext_alpn_add_clienthello(SSL *ssl, CBB *out) { if (ssl->alpn_client_proto_list == NULL || ssl->s3->initial_handshake_complete) { return 1; } CBB contents, proto_list; if (!CBB_add_u16(out, TLSEXT_TYPE_application_layer_protocol_negotiation) || !CBB_add_u16_length_prefixed(out, &contents) || !CBB_add_u16_length_prefixed(&contents, &proto_list) || !CBB_add_bytes(&proto_list, ssl->alpn_client_proto_list, ssl->alpn_client_proto_list_len) || !CBB_flush(out)) { return 0; } return 1; } static int ext_alpn_parse_serverhello(SSL *ssl, uint8_t *out_alert, CBS *contents) { if (contents == NULL) { return 1; } assert(!ssl->s3->initial_handshake_complete); assert(ssl->alpn_client_proto_list != NULL); if (ssl->s3->next_proto_neg_seen) { /* NPN and ALPN may not be negotiated in the same connection. */ *out_alert = SSL_AD_ILLEGAL_PARAMETER; OPENSSL_PUT_ERROR(SSL, SSL_R_NEGOTIATED_BOTH_NPN_AND_ALPN); return 0; } /* The extension data consists of a ProtocolNameList which must have * exactly one ProtocolName. Each of these is length-prefixed. */ CBS protocol_name_list, protocol_name; if (!CBS_get_u16_length_prefixed(contents, &protocol_name_list) || CBS_len(contents) != 0 || !CBS_get_u8_length_prefixed(&protocol_name_list, &protocol_name) || /* Empty protocol names are forbidden. */ CBS_len(&protocol_name) == 0 || CBS_len(&protocol_name_list) != 0) { return 0; } if (!CBS_stow(&protocol_name, &ssl->s3->alpn_selected, &ssl->s3->alpn_selected_len)) { *out_alert = SSL_AD_INTERNAL_ERROR; return 0; } return 1; } static int ext_alpn_parse_clienthello(SSL *ssl, uint8_t *out_alert, CBS *contents) { if (contents == NULL) { return 1; } if (ssl->ctx->alpn_select_cb == NULL || ssl->s3->initial_handshake_complete) { return 1; } /* ALPN takes precedence over NPN. */ ssl->s3->next_proto_neg_seen = 0; CBS protocol_name_list; if (!CBS_get_u16_length_prefixed(contents, &protocol_name_list) || CBS_len(contents) != 0 || CBS_len(&protocol_name_list) < 2) { return 0; } /* Validate the protocol list. */ CBS protocol_name_list_copy = protocol_name_list; while (CBS_len(&protocol_name_list_copy) > 0) { CBS protocol_name; if (!CBS_get_u8_length_prefixed(&protocol_name_list_copy, &protocol_name) || /* Empty protocol names are forbidden. */ CBS_len(&protocol_name) == 0) { return 0; } } const uint8_t *selected; uint8_t selected_len; if (ssl->ctx->alpn_select_cb( ssl, &selected, &selected_len, CBS_data(&protocol_name_list), CBS_len(&protocol_name_list), ssl->ctx->alpn_select_cb_arg) == SSL_TLSEXT_ERR_OK) { OPENSSL_free(ssl->s3->alpn_selected); ssl->s3->alpn_selected = BUF_memdup(selected, selected_len); if (ssl->s3->alpn_selected == NULL) { *out_alert = SSL_AD_INTERNAL_ERROR; return 0; } ssl->s3->alpn_selected_len = selected_len; } return 1; } static int ext_alpn_add_serverhello(SSL *ssl, CBB *out) { if (ssl->s3->alpn_selected == NULL) { return 1; } CBB contents, proto_list, proto; if (!CBB_add_u16(out, TLSEXT_TYPE_application_layer_protocol_negotiation) || !CBB_add_u16_length_prefixed(out, &contents) || !CBB_add_u16_length_prefixed(&contents, &proto_list) || !CBB_add_u8_length_prefixed(&proto_list, &proto) || !CBB_add_bytes(&proto, ssl->s3->alpn_selected, ssl->s3->alpn_selected_len) || !CBB_flush(out)) { return 0; } return 1; } /* Channel ID. * * https://tools.ietf.org/html/draft-balfanz-tls-channelid-01 */ static void ext_channel_id_init(SSL *ssl) { ssl->s3->tlsext_channel_id_valid = 0; } static int ext_channel_id_add_clienthello(SSL *ssl, CBB *out) { if (!ssl->tlsext_channel_id_enabled || SSL_IS_DTLS(ssl)) { return 1; } if (!CBB_add_u16(out, TLSEXT_TYPE_channel_id) || !CBB_add_u16(out, 0 /* length */)) { return 0; } return 1; } static int ext_channel_id_parse_serverhello(SSL *ssl, uint8_t *out_alert, CBS *contents) { if (contents == NULL) { return 1; } assert(!SSL_IS_DTLS(ssl)); assert(ssl->tlsext_channel_id_enabled); if (CBS_len(contents) != 0) { return 0; } ssl->s3->tlsext_channel_id_valid = 1; return 1; } static int ext_channel_id_parse_clienthello(SSL *ssl, uint8_t *out_alert, CBS *contents) { if (contents == NULL || !ssl->tlsext_channel_id_enabled || SSL_IS_DTLS(ssl)) { return 1; } if (CBS_len(contents) != 0) { return 0; } ssl->s3->tlsext_channel_id_valid = 1; return 1; } static int ext_channel_id_add_serverhello(SSL *ssl, CBB *out) { if (!ssl->s3->tlsext_channel_id_valid) { return 1; } if (!CBB_add_u16(out, TLSEXT_TYPE_channel_id) || !CBB_add_u16(out, 0 /* length */)) { return 0; } return 1; } /* Secure Real-time Transport Protocol (SRTP) extension. * * https://tools.ietf.org/html/rfc5764 */ static void ext_srtp_init(SSL *ssl) { ssl->srtp_profile = NULL; } static int ext_srtp_add_clienthello(SSL *ssl, CBB *out) { STACK_OF(SRTP_PROTECTION_PROFILE) *profiles = SSL_get_srtp_profiles(ssl); if (profiles == NULL) { return 1; } const size_t num_profiles = sk_SRTP_PROTECTION_PROFILE_num(profiles); if (num_profiles == 0) { return 1; } CBB contents, profile_ids; if (!CBB_add_u16(out, TLSEXT_TYPE_srtp) || !CBB_add_u16_length_prefixed(out, &contents) || !CBB_add_u16_length_prefixed(&contents, &profile_ids)) { return 0; } size_t i; for (i = 0; i < num_profiles; i++) { if (!CBB_add_u16(&profile_ids, sk_SRTP_PROTECTION_PROFILE_value(profiles, i)->id)) { return 0; } } if (!CBB_add_u8(&contents, 0 /* empty use_mki value */) || !CBB_flush(out)) { return 0; } return 1; } static int ext_srtp_parse_serverhello(SSL *ssl, uint8_t *out_alert, CBS *contents) { if (contents == NULL) { return 1; } /* The extension consists of a u16-prefixed profile ID list containing a * single uint16_t profile ID, then followed by a u8-prefixed srtp_mki field. * * See https://tools.ietf.org/html/rfc5764#section-4.1.1 */ CBS profile_ids, srtp_mki; uint16_t profile_id; if (!CBS_get_u16_length_prefixed(contents, &profile_ids) || !CBS_get_u16(&profile_ids, &profile_id) || CBS_len(&profile_ids) != 0 || !CBS_get_u8_length_prefixed(contents, &srtp_mki) || CBS_len(contents) != 0) { OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST); return 0; } if (CBS_len(&srtp_mki) != 0) { /* Must be no MKI, since we never offer one. */ OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_SRTP_MKI_VALUE); *out_alert = SSL_AD_ILLEGAL_PARAMETER; return 0; } STACK_OF(SRTP_PROTECTION_PROFILE) *profiles = SSL_get_srtp_profiles(ssl); /* Check to see if the server gave us something we support (and presumably * offered). */ size_t i; for (i = 0; i < sk_SRTP_PROTECTION_PROFILE_num(profiles); i++) { const SRTP_PROTECTION_PROFILE *profile = sk_SRTP_PROTECTION_PROFILE_value(profiles, i); if (profile->id == profile_id) { ssl->srtp_profile = profile; return 1; } } OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST); *out_alert = SSL_AD_ILLEGAL_PARAMETER; return 0; } static int ext_srtp_parse_clienthello(SSL *ssl, uint8_t *out_alert, CBS *contents) { if (contents == NULL) { return 1; } CBS profile_ids, srtp_mki; if (!CBS_get_u16_length_prefixed(contents, &profile_ids) || CBS_len(&profile_ids) < 2 || !CBS_get_u8_length_prefixed(contents, &srtp_mki) || CBS_len(contents) != 0) { OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST); return 0; } /* Discard the MKI value for now. */ const STACK_OF(SRTP_PROTECTION_PROFILE) *server_profiles = SSL_get_srtp_profiles(ssl); /* Pick the server's most preferred profile. */ size_t i; for (i = 0; i < sk_SRTP_PROTECTION_PROFILE_num(server_profiles); i++) { const SRTP_PROTECTION_PROFILE *server_profile = sk_SRTP_PROTECTION_PROFILE_value(server_profiles, i); CBS profile_ids_tmp; CBS_init(&profile_ids_tmp, CBS_data(&profile_ids), CBS_len(&profile_ids)); while (CBS_len(&profile_ids_tmp) > 0) { uint16_t profile_id; if (!CBS_get_u16(&profile_ids_tmp, &profile_id)) { return 0; } if (server_profile->id == profile_id) { ssl->srtp_profile = server_profile; return 1; } } } return 1; } static int ext_srtp_add_serverhello(SSL *ssl, CBB *out) { if (ssl->srtp_profile == NULL) { return 1; } CBB contents, profile_ids; if (!CBB_add_u16(out, TLSEXT_TYPE_srtp) || !CBB_add_u16_length_prefixed(out, &contents) || !CBB_add_u16_length_prefixed(&contents, &profile_ids) || !CBB_add_u16(&profile_ids, ssl->srtp_profile->id) || !CBB_add_u8(&contents, 0 /* empty MKI */) || !CBB_flush(out)) { return 0; } return 1; } /* EC point formats. * * https://tools.ietf.org/html/rfc4492#section-5.1.2 */ static int ssl_any_ec_cipher_suites_enabled(const SSL *ssl) { if (ssl->version < TLS1_VERSION && !SSL_IS_DTLS(ssl)) { return 0; } const STACK_OF(SSL_CIPHER) *cipher_stack = SSL_get_ciphers(ssl); size_t i; for (i = 0; i < sk_SSL_CIPHER_num(cipher_stack); i++) { const SSL_CIPHER *cipher = sk_SSL_CIPHER_value(cipher_stack, i); const uint32_t alg_k = cipher->algorithm_mkey; const uint32_t alg_a = cipher->algorithm_auth; if ((alg_k & SSL_kECDHE) || (alg_a & SSL_aECDSA)) { return 1; } } return 0; } static int ext_ec_point_add_extension(SSL *ssl, CBB *out) { CBB contents, formats; if (!CBB_add_u16(out, TLSEXT_TYPE_ec_point_formats) || !CBB_add_u16_length_prefixed(out, &contents) || !CBB_add_u8_length_prefixed(&contents, &formats) || !CBB_add_u8(&formats, TLSEXT_ECPOINTFORMAT_uncompressed) || !CBB_flush(out)) { return 0; } return 1; } static int ext_ec_point_add_clienthello(SSL *ssl, CBB *out) { if (!ssl_any_ec_cipher_suites_enabled(ssl)) { return 1; } return ext_ec_point_add_extension(ssl, out); } static int ext_ec_point_parse_serverhello(SSL *ssl, uint8_t *out_alert, CBS *contents) { if (contents == NULL) { return 1; } CBS ec_point_format_list; if (!CBS_get_u8_length_prefixed(contents, &ec_point_format_list) || CBS_len(contents) != 0) { return 0; } /* Per RFC 4492, section 5.1.2, implementations MUST support the uncompressed * point format. */ if (memchr(CBS_data(&ec_point_format_list), TLSEXT_ECPOINTFORMAT_uncompressed, CBS_len(&ec_point_format_list)) == NULL) { *out_alert = SSL_AD_ILLEGAL_PARAMETER; return 0; } return 1; } static int ext_ec_point_parse_clienthello(SSL *ssl, uint8_t *out_alert, CBS *contents) { return ext_ec_point_parse_serverhello(ssl, out_alert, contents); } static int ext_ec_point_add_serverhello(SSL *ssl, CBB *out) { const uint32_t alg_k = ssl->s3->tmp.new_cipher->algorithm_mkey; const uint32_t alg_a = ssl->s3->tmp.new_cipher->algorithm_auth; const int using_ecc = (alg_k & SSL_kECDHE) || (alg_a & SSL_aECDSA); if (!using_ecc) { return 1; } return ext_ec_point_add_extension(ssl, out); } /* EC supported curves. * * https://tools.ietf.org/html/rfc4492#section-5.1.2 */ static void ext_ec_curves_init(SSL *ssl) { OPENSSL_free(ssl->s3->tmp.peer_ellipticcurvelist); ssl->s3->tmp.peer_ellipticcurvelist = NULL; ssl->s3->tmp.peer_ellipticcurvelist_length = 0; } static int ext_ec_curves_add_clienthello(SSL *ssl, CBB *out) { if (!ssl_any_ec_cipher_suites_enabled(ssl)) { return 1; } CBB contents, curves_bytes; if (!CBB_add_u16(out, TLSEXT_TYPE_elliptic_curves) || !CBB_add_u16_length_prefixed(out, &contents) || !CBB_add_u16_length_prefixed(&contents, &curves_bytes)) { return 0; } const uint16_t *curves; size_t curves_len; tls1_get_curvelist(ssl, 0, &curves, &curves_len); size_t i; for (i = 0; i < curves_len; i++) { if (!CBB_add_u16(&curves_bytes, curves[i])) { return 0; } } return CBB_flush(out); } static int ext_ec_curves_parse_serverhello(SSL *ssl, uint8_t *out_alert, CBS *contents) { /* This extension is not expected to be echoed by servers and is ignored. */ return 1; } static int ext_ec_curves_parse_clienthello(SSL *ssl, uint8_t *out_alert, CBS *contents) { if (contents == NULL) { return 1; } CBS elliptic_curve_list; if (!CBS_get_u16_length_prefixed(contents, &elliptic_curve_list) || CBS_len(&elliptic_curve_list) == 0 || (CBS_len(&elliptic_curve_list) & 1) != 0 || CBS_len(contents) != 0) { return 0; } ssl->s3->tmp.peer_ellipticcurvelist = (uint16_t *)OPENSSL_malloc(CBS_len(&elliptic_curve_list)); if (ssl->s3->tmp.peer_ellipticcurvelist == NULL) { *out_alert = SSL_AD_INTERNAL_ERROR; return 0; } const size_t num_curves = CBS_len(&elliptic_curve_list) / 2; size_t i; for (i = 0; i < num_curves; i++) { if (!CBS_get_u16(&elliptic_curve_list, &ssl->s3->tmp.peer_ellipticcurvelist[i])) { goto err; } } assert(CBS_len(&elliptic_curve_list) == 0); ssl->s3->tmp.peer_ellipticcurvelist_length = num_curves; return 1; err: OPENSSL_free(ssl->s3->tmp.peer_ellipticcurvelist); ssl->s3->tmp.peer_ellipticcurvelist = NULL; *out_alert = SSL_AD_INTERNAL_ERROR; return 0; } static int ext_ec_curves_add_serverhello(SSL *ssl, CBB *out) { /* Servers don't echo this extension. */ return 1; } /* kExtensions contains all the supported extensions. */ static const struct tls_extension kExtensions[] = { { /* The renegotiation extension must always be at index zero because the * |received| and |sent| bitsets need to be tweaked when the "extension" is * sent as an SCSV. */ TLSEXT_TYPE_renegotiate, NULL, ext_ri_add_clienthello, ext_ri_parse_serverhello, ext_ri_parse_clienthello, ext_ri_add_serverhello, }, { TLSEXT_TYPE_server_name, ext_sni_init, ext_sni_add_clienthello, ext_sni_parse_serverhello, ext_sni_parse_clienthello, ext_sni_add_serverhello, }, { TLSEXT_TYPE_extended_master_secret, ext_ems_init, ext_ems_add_clienthello, ext_ems_parse_serverhello, ext_ems_parse_clienthello, ext_ems_add_serverhello, }, { TLSEXT_TYPE_session_ticket, NULL, ext_ticket_add_clienthello, ext_ticket_parse_serverhello, ext_ticket_parse_clienthello, ext_ticket_add_serverhello, }, { TLSEXT_TYPE_signature_algorithms, NULL, ext_sigalgs_add_clienthello, ext_sigalgs_parse_serverhello, ext_sigalgs_parse_clienthello, ext_sigalgs_add_serverhello, }, { TLSEXT_TYPE_status_request, ext_ocsp_init, ext_ocsp_add_clienthello, ext_ocsp_parse_serverhello, ext_ocsp_parse_clienthello, ext_ocsp_add_serverhello, }, { TLSEXT_TYPE_next_proto_neg, ext_npn_init, ext_npn_add_clienthello, ext_npn_parse_serverhello, ext_npn_parse_clienthello, ext_npn_add_serverhello, }, { TLSEXT_TYPE_certificate_timestamp, NULL, ext_sct_add_clienthello, ext_sct_parse_serverhello, ext_sct_parse_clienthello, ext_sct_add_serverhello, }, { TLSEXT_TYPE_application_layer_protocol_negotiation, ext_alpn_init, ext_alpn_add_clienthello, ext_alpn_parse_serverhello, ext_alpn_parse_clienthello, ext_alpn_add_serverhello, }, { TLSEXT_TYPE_channel_id, ext_channel_id_init, ext_channel_id_add_clienthello, ext_channel_id_parse_serverhello, ext_channel_id_parse_clienthello, ext_channel_id_add_serverhello, }, { TLSEXT_TYPE_srtp, ext_srtp_init, ext_srtp_add_clienthello, ext_srtp_parse_serverhello, ext_srtp_parse_clienthello, ext_srtp_add_serverhello, }, { TLSEXT_TYPE_ec_point_formats, NULL, ext_ec_point_add_clienthello, ext_ec_point_parse_serverhello, ext_ec_point_parse_clienthello, ext_ec_point_add_serverhello, }, { TLSEXT_TYPE_elliptic_curves, ext_ec_curves_init, ext_ec_curves_add_clienthello, ext_ec_curves_parse_serverhello, ext_ec_curves_parse_clienthello, ext_ec_curves_add_serverhello, }, }; #define kNumExtensions (sizeof(kExtensions) / sizeof(struct tls_extension)) OPENSSL_COMPILE_ASSERT(kNumExtensions <= sizeof(((SSL *)NULL)->s3->tmp.extensions.sent) * 8, too_many_extensions_for_sent_bitset); OPENSSL_COMPILE_ASSERT(kNumExtensions <= sizeof(((SSL *)NULL)->s3->tmp.extensions.received) * 8, too_many_extensions_for_received_bitset); static const struct tls_extension *tls_extension_find(uint32_t *out_index, uint16_t value) { unsigned i; for (i = 0; i < kNumExtensions; i++) { if (kExtensions[i].value == value) { *out_index = i; return &kExtensions[i]; } } return NULL; } int SSL_extension_supported(unsigned extension_value) { uint32_t index; return extension_value == TLSEXT_TYPE_padding || tls_extension_find(&index, extension_value) != NULL; } int ssl_add_clienthello_tlsext(SSL *ssl, CBB *out, size_t header_len) { /* don't add extensions for SSLv3 unless doing secure renegotiation */ if (ssl->client_version == SSL3_VERSION && !ssl->s3->send_connection_binding) { return 1; } size_t orig_len = CBB_len(out); CBB extensions; if (!CBB_add_u16_length_prefixed(out, &extensions)) { goto err; } ssl->s3->tmp.extensions.sent = 0; ssl->s3->tmp.custom_extensions.sent = 0; size_t i; for (i = 0; i < kNumExtensions; i++) { if (kExtensions[i].init != NULL) { kExtensions[i].init(ssl); } } for (i = 0; i < kNumExtensions; i++) { const size_t len_before = CBB_len(&extensions); if (!kExtensions[i].add_clienthello(ssl, &extensions)) { OPENSSL_PUT_ERROR(SSL, SSL_R_ERROR_ADDING_EXTENSION); ERR_add_error_dataf("extension: %u", (unsigned)kExtensions[i].value); goto err; } if (CBB_len(&extensions) != len_before) { ssl->s3->tmp.extensions.sent |= (1u << i); } } if (!custom_ext_add_clienthello(ssl, &extensions)) { goto err; } if (!SSL_IS_DTLS(ssl)) { header_len += CBB_len(&extensions) - orig_len; if (header_len > 0xff && header_len < 0x200) { /* Add padding to workaround bugs in F5 terminators. See * https://tools.ietf.org/html/draft-agl-tls-padding-03 * * NB: because this code works out the length of all existing extensions * it MUST always appear last. */ size_t padding_len = 0x200 - header_len; /* Extensions take at least four bytes to encode. Always include least * one byte of data if including the extension. WebSphere Application * Server 7.0 is intolerant to the last extension being zero-length. */ if (padding_len >= 4 + 1) { padding_len -= 4; } else { padding_len = 1; } uint8_t *padding_bytes; if (!CBB_add_u16(&extensions, TLSEXT_TYPE_padding) || !CBB_add_u16(&extensions, padding_len) || !CBB_add_space(&extensions, &padding_bytes, padding_len)) { goto err; } memset(padding_bytes, 0, padding_len); } } /* If only two bytes have been written then the extensions are actually empty * and those two bytes are the zero length. In that case, we don't bother * sending the extensions length. */ if (CBB_len(&extensions) - orig_len == 2) { CBB_discard_child(out); } return CBB_flush(out); err: OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); return 0; } uint8_t *ssl_add_serverhello_tlsext(SSL *s, uint8_t *const buf, uint8_t *const limit) { CBB cbb, extensions; CBB_zero(&cbb); if (!CBB_init_fixed(&cbb, buf, limit - buf) || !CBB_add_u16_length_prefixed(&cbb, &extensions)) { goto err; } unsigned i; for (i = 0; i < kNumExtensions; i++) { if (!(s->s3->tmp.extensions.received & (1u << i))) { /* Don't send extensions that were not received. */ continue; } if (!kExtensions[i].add_serverhello(s, &extensions)) { OPENSSL_PUT_ERROR(SSL, SSL_R_ERROR_ADDING_EXTENSION); ERR_add_error_dataf("extension: %u", (unsigned)kExtensions[i].value); goto err; } } if (!custom_ext_add_serverhello(s, &extensions)) { goto err; } if (!CBB_flush(&cbb)) { goto err; } uint8_t *ret = buf; const size_t cbb_len = CBB_len(&cbb); /* If only two bytes have been written then the extensions are actually empty * and those two bytes are the zero length. In that case, we don't bother * sending the extensions length. */ if (cbb_len > 2) { ret += cbb_len; } CBB_cleanup(&cbb); return ret; err: CBB_cleanup(&cbb); OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); return NULL; } static int ssl_scan_clienthello_tlsext(SSL *s, CBS *cbs, int *out_alert) { size_t i; for (i = 0; i < kNumExtensions; i++) { if (kExtensions[i].init != NULL) { kExtensions[i].init(s); } } s->s3->tmp.extensions.received = 0; s->s3->tmp.custom_extensions.received = 0; /* The renegotiation extension must always be at index zero because the * |received| and |sent| bitsets need to be tweaked when the "extension" is * sent as an SCSV. */ assert(kExtensions[0].value == TLSEXT_TYPE_renegotiate); /* There may be no extensions. */ if (CBS_len(cbs) != 0) { /* Decode the extensions block and check it is valid. */ CBS extensions; if (!CBS_get_u16_length_prefixed(cbs, &extensions) || !tls1_check_duplicate_extensions(&extensions)) { *out_alert = SSL_AD_DECODE_ERROR; return 0; } while (CBS_len(&extensions) != 0) { uint16_t type; CBS extension; /* Decode the next extension. */ if (!CBS_get_u16(&extensions, &type) || !CBS_get_u16_length_prefixed(&extensions, &extension)) { *out_alert = SSL_AD_DECODE_ERROR; return 0; } /* RFC 5746 made the existence of extensions in SSL 3.0 somewhat * ambiguous. Ignore all but the renegotiation_info extension. */ if (s->version == SSL3_VERSION && type != TLSEXT_TYPE_renegotiate) { continue; } unsigned ext_index; const struct tls_extension *const ext = tls_extension_find(&ext_index, type); if (ext == NULL) { if (!custom_ext_parse_clienthello(s, out_alert, type, &extension)) { OPENSSL_PUT_ERROR(SSL, SSL_R_ERROR_PARSING_EXTENSION); return 0; } continue; } s->s3->tmp.extensions.received |= (1u << ext_index); uint8_t alert = SSL_AD_DECODE_ERROR; if (!ext->parse_clienthello(s, &alert, &extension)) { *out_alert = alert; OPENSSL_PUT_ERROR(SSL, SSL_R_ERROR_PARSING_EXTENSION); ERR_add_error_dataf("extension: %u", (unsigned)type); return 0; } } } for (i = 0; i < kNumExtensions; i++) { if (!(s->s3->tmp.extensions.received & (1u << i))) { /* Extension wasn't observed so call the callback with a NULL * parameter. */ uint8_t alert = SSL_AD_DECODE_ERROR; if (!kExtensions[i].parse_clienthello(s, &alert, NULL)) { OPENSSL_PUT_ERROR(SSL, SSL_R_MISSING_EXTENSION); ERR_add_error_dataf("extension: %u", (unsigned)kExtensions[i].value); *out_alert = alert; return 0; } } } return 1; } int ssl_parse_clienthello_tlsext(SSL *s, CBS *cbs) { int alert = -1; if (ssl_scan_clienthello_tlsext(s, cbs, &alert) <= 0) { ssl3_send_alert(s, SSL3_AL_FATAL, alert); return 0; } if (ssl_check_clienthello_tlsext(s) <= 0) { OPENSSL_PUT_ERROR(SSL, SSL_R_CLIENTHELLO_TLSEXT); return 0; } return 1; } static int ssl_scan_serverhello_tlsext(SSL *s, CBS *cbs, int *out_alert) { uint32_t received = 0; assert(kNumExtensions <= sizeof(received) * 8); if (CBS_len(cbs) != 0) { /* Decode the extensions block and check it is valid. */ CBS extensions; if (!CBS_get_u16_length_prefixed(cbs, &extensions) || !tls1_check_duplicate_extensions(&extensions)) { *out_alert = SSL_AD_DECODE_ERROR; return 0; } while (CBS_len(&extensions) != 0) { uint16_t type; CBS extension; /* Decode the next extension. */ if (!CBS_get_u16(&extensions, &type) || !CBS_get_u16_length_prefixed(&extensions, &extension)) { *out_alert = SSL_AD_DECODE_ERROR; return 0; } unsigned ext_index; const struct tls_extension *const ext = tls_extension_find(&ext_index, type); if (ext == NULL) { if (!custom_ext_parse_serverhello(s, out_alert, type, &extension)) { return 0; } continue; } if (!(s->s3->tmp.extensions.sent & (1u << ext_index))) { /* If the extension was never sent then it is illegal. */ OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_EXTENSION); ERR_add_error_dataf("extension :%u", (unsigned)type); *out_alert = SSL_AD_DECODE_ERROR; return 0; } received |= (1u << ext_index); uint8_t alert = SSL_AD_DECODE_ERROR; if (!ext->parse_serverhello(s, &alert, &extension)) { OPENSSL_PUT_ERROR(SSL, SSL_R_ERROR_PARSING_EXTENSION); ERR_add_error_dataf("extension: %u", (unsigned)type); *out_alert = alert; return 0; } } } size_t i; for (i = 0; i < kNumExtensions; i++) { if (!(received & (1u << i))) { /* Extension wasn't observed so call the callback with a NULL * parameter. */ uint8_t alert = SSL_AD_DECODE_ERROR; if (!kExtensions[i].parse_serverhello(s, &alert, NULL)) { OPENSSL_PUT_ERROR(SSL, SSL_R_MISSING_EXTENSION); ERR_add_error_dataf("extension: %u", (unsigned)kExtensions[i].value); *out_alert = alert; return 0; } } } return 1; } static int ssl_check_clienthello_tlsext(SSL *s) { int ret = SSL_TLSEXT_ERR_NOACK; int al = SSL_AD_UNRECOGNIZED_NAME; /* The handling of the ECPointFormats extension is done elsewhere, namely in * ssl3_choose_cipher in s3_lib.c. */ if (s->ctx != NULL && s->ctx->tlsext_servername_callback != 0) { ret = s->ctx->tlsext_servername_callback(s, &al, s->ctx->tlsext_servername_arg); } else if (s->initial_ctx != NULL && s->initial_ctx->tlsext_servername_callback != 0) { ret = s->initial_ctx->tlsext_servername_callback( s, &al, s->initial_ctx->tlsext_servername_arg); } switch (ret) { case SSL_TLSEXT_ERR_ALERT_FATAL: ssl3_send_alert(s, SSL3_AL_FATAL, al); return -1; case SSL_TLSEXT_ERR_ALERT_WARNING: ssl3_send_alert(s, SSL3_AL_WARNING, al); return 1; case SSL_TLSEXT_ERR_NOACK: s->s3->tmp.should_ack_sni = 0; return 1; default: return 1; } } static int ssl_check_serverhello_tlsext(SSL *s) { int ret = SSL_TLSEXT_ERR_OK; int al = SSL_AD_UNRECOGNIZED_NAME; if (s->ctx != NULL && s->ctx->tlsext_servername_callback != 0) { ret = s->ctx->tlsext_servername_callback(s, &al, s->ctx->tlsext_servername_arg); } else if (s->initial_ctx != NULL && s->initial_ctx->tlsext_servername_callback != 0) { ret = s->initial_ctx->tlsext_servername_callback( s, &al, s->initial_ctx->tlsext_servername_arg); } switch (ret) { case SSL_TLSEXT_ERR_ALERT_FATAL: ssl3_send_alert(s, SSL3_AL_FATAL, al); return -1; case SSL_TLSEXT_ERR_ALERT_WARNING: ssl3_send_alert(s, SSL3_AL_WARNING, al); return 1; default: return 1; } } int ssl_parse_serverhello_tlsext(SSL *s, CBS *cbs) { int alert = -1; if (ssl_scan_serverhello_tlsext(s, cbs, &alert) <= 0) { ssl3_send_alert(s, SSL3_AL_FATAL, alert); return 0; } if (ssl_check_serverhello_tlsext(s) <= 0) { OPENSSL_PUT_ERROR(SSL, SSL_R_SERVERHELLO_TLSEXT); return 0; } return 1; } int tls_process_ticket(SSL *ssl, SSL_SESSION **out_session, int *out_send_ticket, const uint8_t *ticket, size_t ticket_len, const uint8_t *session_id, size_t session_id_len) { int ret = 1; /* Most errors are non-fatal. */ SSL_CTX *ssl_ctx = ssl->initial_ctx; uint8_t *plaintext = NULL; HMAC_CTX hmac_ctx; HMAC_CTX_init(&hmac_ctx); EVP_CIPHER_CTX cipher_ctx; EVP_CIPHER_CTX_init(&cipher_ctx); *out_send_ticket = 0; *out_session = NULL; if (session_id_len > SSL_MAX_SSL_SESSION_ID_LENGTH) { goto done; } if (ticket_len == 0) { /* The client will accept a ticket but doesn't currently have one. */ *out_send_ticket = 1; goto done; } /* Ensure there is room for the key name and the largest IV * |tlsext_ticket_key_cb| may try to consume. The real limit may be lower, but * the maximum IV length should be well under the minimum size for the * session material and HMAC. */ if (ticket_len < SSL_TICKET_KEY_NAME_LEN + EVP_MAX_IV_LENGTH) { goto done; } const uint8_t *iv = ticket + SSL_TICKET_KEY_NAME_LEN; if (ssl_ctx->tlsext_ticket_key_cb != NULL) { int cb_ret = ssl_ctx->tlsext_ticket_key_cb(ssl, (uint8_t*)ticket /* name */, (uint8_t*)iv, &cipher_ctx, &hmac_ctx, 0 /* decrypt */); if (cb_ret < 0) { ret = 0; goto done; } if (cb_ret == 0) { goto done; } if (cb_ret == 2) { *out_send_ticket = 1; } } else { /* Check the key name matches. */ if (memcmp(ticket, ssl_ctx->tlsext_tick_key_name, SSL_TICKET_KEY_NAME_LEN) != 0) { goto done; } if (!HMAC_Init_ex(&hmac_ctx, ssl_ctx->tlsext_tick_hmac_key, sizeof(ssl_ctx->tlsext_tick_hmac_key), tlsext_tick_md(), NULL) || !EVP_DecryptInit_ex(&cipher_ctx, EVP_aes_128_cbc(), NULL, ssl_ctx->tlsext_tick_aes_key, iv)) { ret = 0; goto done; } } size_t iv_len = EVP_CIPHER_CTX_iv_length(&cipher_ctx); /* Check the MAC at the end of the ticket. */ uint8_t mac[EVP_MAX_MD_SIZE]; size_t mac_len = HMAC_size(&hmac_ctx); if (ticket_len < SSL_TICKET_KEY_NAME_LEN + iv_len + 1 + mac_len) { /* The ticket must be large enough for key name, IV, data, and MAC. */ goto done; } HMAC_Update(&hmac_ctx, ticket, ticket_len - mac_len); HMAC_Final(&hmac_ctx, mac, NULL); if (CRYPTO_memcmp(mac, ticket + (ticket_len - mac_len), mac_len) != 0) { goto done; } /* Decrypt the session data. */ const uint8_t *ciphertext = ticket + SSL_TICKET_KEY_NAME_LEN + iv_len; size_t ciphertext_len = ticket_len - SSL_TICKET_KEY_NAME_LEN - iv_len - mac_len; plaintext = OPENSSL_malloc(ciphertext_len); if (plaintext == NULL) { ret = 0; goto done; } if (ciphertext_len >= INT_MAX) { goto done; } int len1, len2; if (!EVP_DecryptUpdate(&cipher_ctx, plaintext, &len1, ciphertext, (int)ciphertext_len) || !EVP_DecryptFinal_ex(&cipher_ctx, plaintext + len1, &len2)) { ERR_clear_error(); /* Don't leave an error on the queue. */ goto done; } /* Decode the session. */ SSL_SESSION *session = SSL_SESSION_from_bytes(plaintext, len1 + len2); if (session == NULL) { ERR_clear_error(); /* Don't leave an error on the queue. */ goto done; } /* Copy the client's session ID into the new session, to denote the ticket has * been accepted. */ memcpy(session->session_id, session_id, session_id_len); session->session_id_length = session_id_len; *out_session = session; done: OPENSSL_free(plaintext); HMAC_CTX_cleanup(&hmac_ctx); EVP_CIPHER_CTX_cleanup(&cipher_ctx); return ret; } /* Tables to translate from NIDs to TLS v1.2 ids */ typedef struct { int nid; int id; } tls12_lookup; static const tls12_lookup tls12_md[] = {{NID_md5, TLSEXT_hash_md5}, {NID_sha1, TLSEXT_hash_sha1}, {NID_sha224, TLSEXT_hash_sha224}, {NID_sha256, TLSEXT_hash_sha256}, {NID_sha384, TLSEXT_hash_sha384}, {NID_sha512, TLSEXT_hash_sha512}}; static const tls12_lookup tls12_sig[] = {{EVP_PKEY_RSA, TLSEXT_signature_rsa}, {EVP_PKEY_EC, TLSEXT_signature_ecdsa}}; static int tls12_find_id(int nid, const tls12_lookup *table, size_t tlen) { size_t i; for (i = 0; i < tlen; i++) { if (table[i].nid == nid) { return table[i].id; } } return -1; } int tls12_get_sigid(int pkey_type) { return tls12_find_id(pkey_type, tls12_sig, sizeof(tls12_sig) / sizeof(tls12_lookup)); } int tls12_get_sigandhash(SSL *ssl, uint8_t *p, const EVP_MD *md) { int sig_id, md_id; if (!md) { return 0; } md_id = tls12_find_id(EVP_MD_type(md), tls12_md, sizeof(tls12_md) / sizeof(tls12_lookup)); if (md_id == -1) { return 0; } sig_id = tls12_get_sigid(ssl_private_key_type(ssl)); if (sig_id == -1) { return 0; } p[0] = (uint8_t)md_id; p[1] = (uint8_t)sig_id; return 1; } const EVP_MD *tls12_get_hash(uint8_t hash_alg) { switch (hash_alg) { case TLSEXT_hash_md5: return EVP_md5(); case TLSEXT_hash_sha1: return EVP_sha1(); case TLSEXT_hash_sha224: return EVP_sha224(); case TLSEXT_hash_sha256: return EVP_sha256(); case TLSEXT_hash_sha384: return EVP_sha384(); case TLSEXT_hash_sha512: return EVP_sha512(); default: return NULL; } } /* tls12_get_pkey_type returns the EVP_PKEY type corresponding to TLS signature * algorithm |sig_alg|. It returns -1 if the type is unknown. */ static int tls12_get_pkey_type(uint8_t sig_alg) { switch (sig_alg) { case TLSEXT_signature_rsa: return EVP_PKEY_RSA; case TLSEXT_signature_ecdsa: return EVP_PKEY_EC; default: return -1; } } OPENSSL_COMPILE_ASSERT(sizeof(TLS_SIGALGS) == 2, sizeof_tls_sigalgs_is_not_two); int tls1_parse_peer_sigalgs(SSL *ssl, const CBS *in_sigalgs) { /* Extension ignored for inappropriate versions */ if (!SSL_USE_SIGALGS(ssl)) { return 1; } CERT *const cert = ssl->cert; OPENSSL_free(cert->peer_sigalgs); cert->peer_sigalgs = NULL; cert->peer_sigalgslen = 0; size_t num_sigalgs = CBS_len(in_sigalgs); if (num_sigalgs % 2 != 0) { return 0; } num_sigalgs /= 2; /* supported_signature_algorithms in the certificate request is * allowed to be empty. */ if (num_sigalgs == 0) { return 1; } /* This multiplication doesn't overflow because sizeof(TLS_SIGALGS) is two * (statically asserted above) and we just divided |num_sigalgs| by two. */ cert->peer_sigalgs = OPENSSL_malloc(num_sigalgs * sizeof(TLS_SIGALGS)); if (cert->peer_sigalgs == NULL) { return 0; } cert->peer_sigalgslen = num_sigalgs; CBS sigalgs; CBS_init(&sigalgs, CBS_data(in_sigalgs), CBS_len(in_sigalgs)); size_t i; for (i = 0; i < num_sigalgs; i++) { TLS_SIGALGS *const sigalg = &cert->peer_sigalgs[i]; if (!CBS_get_u8(&sigalgs, &sigalg->rhash) || !CBS_get_u8(&sigalgs, &sigalg->rsign)) { return 0; } } return 1; } const EVP_MD *tls1_choose_signing_digest(SSL *ssl) { CERT *cert = ssl->cert; int type = ssl_private_key_type(ssl); size_t i, j; static const int kDefaultDigestList[] = {NID_sha256, NID_sha384, NID_sha512, NID_sha224, NID_sha1}; const int *digest_nids = kDefaultDigestList; size_t num_digest_nids = sizeof(kDefaultDigestList) / sizeof(kDefaultDigestList[0]); if (cert->digest_nids != NULL) { digest_nids = cert->digest_nids; num_digest_nids = cert->num_digest_nids; } for (i = 0; i < num_digest_nids; i++) { const int digest_nid = digest_nids[i]; for (j = 0; j < cert->peer_sigalgslen; j++) { const EVP_MD *md = tls12_get_hash(cert->peer_sigalgs[j].rhash); if (md == NULL || digest_nid != EVP_MD_type(md) || tls12_get_pkey_type(cert->peer_sigalgs[j].rsign) != type) { continue; } return md; } } /* If no suitable digest may be found, default to SHA-1. */ return EVP_sha1(); } int tls1_channel_id_hash(SSL *ssl, uint8_t *out, size_t *out_len) { int ret = 0; EVP_MD_CTX ctx; EVP_MD_CTX_init(&ctx); if (!EVP_DigestInit_ex(&ctx, EVP_sha256(), NULL)) { goto err; } static const char kClientIDMagic[] = "TLS Channel ID signature"; EVP_DigestUpdate(&ctx, kClientIDMagic, sizeof(kClientIDMagic)); if (ssl->hit) { static const char kResumptionMagic[] = "Resumption"; EVP_DigestUpdate(&ctx, kResumptionMagic, sizeof(kResumptionMagic)); if (ssl->session->original_handshake_hash_len == 0) { OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); goto err; } EVP_DigestUpdate(&ctx, ssl->session->original_handshake_hash, ssl->session->original_handshake_hash_len); } uint8_t handshake_hash[EVP_MAX_MD_SIZE]; int handshake_hash_len = tls1_handshake_digest(ssl, handshake_hash, sizeof(handshake_hash)); if (handshake_hash_len < 0) { goto err; } EVP_DigestUpdate(&ctx, handshake_hash, (size_t)handshake_hash_len); unsigned len_u; EVP_DigestFinal_ex(&ctx, out, &len_u); *out_len = len_u; ret = 1; err: EVP_MD_CTX_cleanup(&ctx); return ret; } /* tls1_record_handshake_hashes_for_channel_id records the current handshake * hashes in |s->session| so that Channel ID resumptions can sign that data. */ int tls1_record_handshake_hashes_for_channel_id(SSL *s) { int digest_len; /* This function should never be called for a resumed session because the * handshake hashes that we wish to record are for the original, full * handshake. */ if (s->hit) { return -1; } digest_len = tls1_handshake_digest(s, s->session->original_handshake_hash, sizeof(s->session->original_handshake_hash)); if (digest_len < 0) { return -1; } s->session->original_handshake_hash_len = digest_len; return 1; }