/* 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" #include "../crypto/internal.h" static int ssl_check_clienthello_tlsext(SSL *ssl); static int ssl_check_serverhello_tlsext(SSL *ssl); 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 = 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; } int ssl_early_callback_init(SSL *ssl, struct ssl_early_callback_ctx *ctx, const uint8_t *in, size_t in_len) { memset(ctx, 0, sizeof(*ctx)); ctx->ssl = ssl; ctx->client_hello = in; ctx->client_hello_len = in_len; CBS client_hello, random, session_id; CBS_init(&client_hello, ctx->client_hello, ctx->client_hello_len); if (!CBS_get_u16(&client_hello, &ctx->version) || !CBS_get_bytes(&client_hello, &random, SSL3_RANDOM_SIZE) || !CBS_get_u8_length_prefixed(&client_hello, &session_id) || CBS_len(&session_id) > SSL_MAX_SSL_SESSION_ID_LENGTH) { return 0; } ctx->random = CBS_data(&random); ctx->random_len = CBS_len(&random); 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) || CBS_len(&cookie) > DTLS1_COOKIE_LENGTH) { return 0; } } CBS cipher_suites, compression_methods; if (!CBS_get_u16_length_prefixed(&client_hello, &cipher_suites) || CBS_len(&cipher_suites) < 2 || (CBS_len(&cipher_suites) & 1) != 0 || !CBS_get_u8_length_prefixed(&client_hello, &compression_methods) || CBS_len(&compression_methods) < 1) { return 0; } ctx->cipher_suites = CBS_data(&cipher_suites); ctx->cipher_suites_len = CBS_len(&cipher_suites); 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. */ CBS extensions; 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; } int ssl_early_callback_get_extension(const struct ssl_early_callback_ctx *ctx, CBS *out, uint16_t extension_type) { CBS extensions; CBS_init(&extensions, ctx->extensions, ctx->extensions_len); while (CBS_len(&extensions) != 0) { /* Decode the next extension. */ uint16_t type; CBS extension; if (!CBS_get_u16(&extensions, &type) || !CBS_get_u16_length_prefixed(&extensions, &extension)) { return 0; } if (type == extension_type) { *out = extension; return 1; } } return 0; } int 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 cbs; if (!ssl_early_callback_get_extension(ctx, &cbs, extension_type)) { return 0; } *out_data = CBS_data(&cbs); *out_len = CBS_len(&cbs); return 1; } static const uint16_t kDefaultGroups[] = { SSL_CURVE_X25519, SSL_CURVE_SECP256R1, SSL_CURVE_SECP384R1, #if defined(BORINGSSL_ANDROID_SYSTEM) SSL_CURVE_SECP521R1, #endif }; void tls1_get_grouplist(SSL *ssl, const uint16_t **out_group_ids, size_t *out_group_ids_len) { *out_group_ids = ssl->supported_group_list; *out_group_ids_len = ssl->supported_group_list_len; if (!*out_group_ids) { *out_group_ids = kDefaultGroups; *out_group_ids_len = OPENSSL_ARRAY_SIZE(kDefaultGroups); } } int tls1_get_shared_group(SSL *ssl, uint16_t *out_group_id) { assert(ssl->server); const uint16_t *groups, *pref, *supp; size_t groups_len, pref_len, supp_len; tls1_get_grouplist(ssl, &groups, &groups_len); /* Clients are not required to send a supported_groups extension. In this * case, the server is free to pick any group it likes. See RFC 4492, * section 4, paragraph 3. * * However, in the interests of compatibility, we will skip ECDH if the * client didn't send an extension because we can't be sure that they'll * support our favoured group. Thus we do not special-case an emtpy * |peer_supported_group_list|. */ if (ssl->options & SSL_OP_CIPHER_SERVER_PREFERENCE) { pref = groups; pref_len = groups_len; supp = ssl->s3->hs->peer_supported_group_list; supp_len = ssl->s3->hs->peer_supported_group_list_len; } else { pref = ssl->s3->hs->peer_supported_group_list; pref_len = ssl->s3->hs->peer_supported_group_list_len; supp = groups; supp_len = groups_len; } for (size_t i = 0; i < pref_len; i++) { for (size_t j = 0; j < supp_len; j++) { if (pref[i] == supp[j]) { *out_group_id = pref[i]; return 1; } } } return 0; } int tls1_set_curves(uint16_t **out_group_ids, size_t *out_group_ids_len, const int *curves, size_t ncurves) { uint16_t *group_ids; group_ids = OPENSSL_malloc(ncurves * sizeof(uint16_t)); if (group_ids == NULL) { return 0; } for (size_t i = 0; i < ncurves; i++) { if (!ssl_nid_to_group_id(&group_ids[i], curves[i])) { OPENSSL_free(group_ids); return 0; } } OPENSSL_free(*out_group_ids); *out_group_ids = group_ids; *out_group_ids_len = ncurves; return 1; } int tls1_set_curves_list(uint16_t **out_group_ids, size_t *out_group_ids_len, const char *curves) { uint16_t *group_ids = NULL; size_t ncurves = 0; const char *col; const char *ptr = curves; do { col = strchr(ptr, ':'); uint16_t group_id; if (!ssl_name_to_group_id(&group_id, ptr, col ? (size_t)(col - ptr) : strlen(ptr))) { goto err; } uint16_t *new_group_ids = OPENSSL_realloc(group_ids, (ncurves + 1) * sizeof(uint16_t)); if (new_group_ids == NULL) { goto err; } group_ids = new_group_ids; group_ids[ncurves] = group_id; ncurves++; if (col) { ptr = col + 1; } } while (col); OPENSSL_free(*out_group_ids); *out_group_ids = group_ids; *out_group_ids_len = ncurves; return 1; err: OPENSSL_free(group_ids); return 0; } int tls1_check_group_id(SSL *ssl, uint16_t group_id) { const uint16_t *groups; size_t groups_len; tls1_get_grouplist(ssl, &groups, &groups_len); for (size_t i = 0; i < groups_len; i++) { if (groups[i] == group_id) { return 1; } } return 0; } /* kVerifySignatureAlgorithms is the default list of accepted signature * algorithms for verifying. * * For now, RSA-PSS signature algorithms are not enabled on Android's system * BoringSSL. Once the change in Chrome has stuck and the values are finalized, * restore them. */ static const uint16_t kVerifySignatureAlgorithms[] = { /* Prefer SHA-256 algorithms. */ SSL_SIGN_ECDSA_SECP256R1_SHA256, #if !defined(BORINGSSL_ANDROID_SYSTEM) SSL_SIGN_RSA_PSS_SHA256, #endif SSL_SIGN_RSA_PKCS1_SHA256, /* Larger hashes are acceptable. */ SSL_SIGN_ECDSA_SECP384R1_SHA384, #if !defined(BORINGSSL_ANDROID_SYSTEM) SSL_SIGN_RSA_PSS_SHA384, #endif SSL_SIGN_RSA_PKCS1_SHA384, /* TODO(davidben): Remove this entry and SSL_CURVE_SECP521R1 from * kDefaultGroups. */ #if defined(BORINGSSL_ANDROID_SYSTEM) SSL_SIGN_ECDSA_SECP521R1_SHA512, #endif #if !defined(BORINGSSL_ANDROID_SYSTEM) SSL_SIGN_RSA_PSS_SHA512, #endif SSL_SIGN_RSA_PKCS1_SHA512, /* For now, SHA-1 is still accepted but least preferable. */ SSL_SIGN_RSA_PKCS1_SHA1, }; /* kSignSignatureAlgorithms is the default list of supported signature * algorithms for signing. * * For now, RSA-PSS signature algorithms are not enabled on Android's system * BoringSSL. Once the change in Chrome has stuck and the values are finalized, * restore them. */ static const uint16_t kSignSignatureAlgorithms[] = { /* Prefer SHA-256 algorithms. */ SSL_SIGN_ECDSA_SECP256R1_SHA256, #if !defined(BORINGSSL_ANDROID_SYSTEM) SSL_SIGN_RSA_PSS_SHA256, #endif SSL_SIGN_RSA_PKCS1_SHA256, /* If needed, sign larger hashes. * * TODO(davidben): Determine which of these may be pruned. */ SSL_SIGN_ECDSA_SECP384R1_SHA384, #if !defined(BORINGSSL_ANDROID_SYSTEM) SSL_SIGN_RSA_PSS_SHA384, #endif SSL_SIGN_RSA_PKCS1_SHA384, SSL_SIGN_ECDSA_SECP521R1_SHA512, #if !defined(BORINGSSL_ANDROID_SYSTEM) SSL_SIGN_RSA_PSS_SHA512, #endif SSL_SIGN_RSA_PKCS1_SHA512, /* If the peer supports nothing else, sign with SHA-1. */ SSL_SIGN_ECDSA_SHA1, SSL_SIGN_RSA_PKCS1_SHA1, }; size_t tls12_get_verify_sigalgs(const SSL *ssl, const uint16_t **out) { *out = kVerifySignatureAlgorithms; return OPENSSL_ARRAY_SIZE(kVerifySignatureAlgorithms); } int tls12_check_peer_sigalg(SSL *ssl, int *out_alert, uint16_t sigalg) { const uint16_t *verify_sigalgs; size_t num_verify_sigalgs = tls12_get_verify_sigalgs(ssl, &verify_sigalgs); for (size_t i = 0; i < num_verify_sigalgs; i++) { if (sigalg == verify_sigalgs[i]) { return 1; } } OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_SIGNATURE_TYPE); *out_alert = SSL_AD_ILLEGAL_PARAMETER; return 0; } /* 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 *ssl) { CERT *c = ssl->cert; int have_rsa = 0, have_ecdsa = 0; c->mask_a = 0; c->mask_k = 0; /* Now go through all signature algorithms seeing if we support any for RSA or * ECDSA. Do this for all versions not just TLS 1.2. */ const uint16_t *sigalgs; size_t num_sigalgs = tls12_get_verify_sigalgs(ssl, &sigalgs); for (size_t i = 0; i < num_sigalgs; i++) { switch (sigalgs[i]) { case SSL_SIGN_RSA_PSS_SHA512: case SSL_SIGN_RSA_PSS_SHA384: case SSL_SIGN_RSA_PSS_SHA256: case SSL_SIGN_RSA_PKCS1_SHA512: case SSL_SIGN_RSA_PKCS1_SHA384: case SSL_SIGN_RSA_PKCS1_SHA256: case SSL_SIGN_RSA_PKCS1_SHA1: have_rsa = 1; break; case SSL_SIGN_ECDSA_SECP521R1_SHA512: case SSL_SIGN_ECDSA_SECP384R1_SHA384: case SSL_SIGN_ECDSA_SECP256R1_SHA256: case SSL_SIGN_ECDSA_SHA1: 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 (!ssl->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); }; static int forbid_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_UNEXPECTED_EXTENSION); return 0; } return 1; } static int ignore_parse_clienthello(SSL *ssl, uint8_t *out_alert, CBS *contents) { /* This extension from the client is handled elsewhere. */ return 1; } static int dont_add_serverhello(SSL *ssl, CBB *out) { return 1; } /* Server name indication (SNI). * * https://tools.ietf.org/html/rfc6066#section-3. */ 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->session == NULL) { assert(ssl->s3->new_session->tlsext_hostname == NULL); ssl->s3->new_session->tlsext_hostname = BUF_strdup(ssl->tlsext_hostname); if (!ssl->s3->new_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; } CBS server_name_list, host_name; uint8_t name_type; if (!CBS_get_u16_length_prefixed(contents, &server_name_list) || !CBS_get_u8(&server_name_list, &name_type) || /* Although the server_name extension was intended to be extensible to * new name types and multiple names, OpenSSL 1.0.x had a bug which meant * different name types will cause an error. Further, RFC 4366 originally * defined syntax inextensibly. RFC 6066 corrected this mistake, but * adding new name types is no longer feasible. * * Act as if the extensibility does not exist to simplify parsing. */ !CBS_get_u16_length_prefixed(&server_name_list, &host_name) || CBS_len(&server_name_list) != 0 || CBS_len(contents) != 0) { return 0; } if (name_type != TLSEXT_NAMETYPE_host_name || 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; } /* TODO(davidben): SNI should be resolved before resumption. We have the * early callback as a replacement, but we should fix the current callback * and avoid the need for |SSL_CTX_set_session_id_context|. */ if (ssl->session == NULL) { assert(ssl->s3->new_session->tlsext_hostname == NULL); /* Copy the hostname as a string. */ if (!CBS_strdup(&host_name, &ssl->s3->new_session->tlsext_hostname)) { *out_alert = SSL_AD_INTERNAL_ERROR; return 0; } ssl->s3->hs->should_ack_sni = 1; } return 1; } static int ext_sni_add_serverhello(SSL *ssl, CBB *out) { if (ssl->session != NULL || !ssl->s3->hs->should_ack_sni || ssl->s3->new_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) { uint16_t min_version, max_version; if (!ssl_get_version_range(ssl, &min_version, &max_version)) { return 0; } /* Renegotiation indication is not necessary in TLS 1.3. */ if (min_version >= TLS1_3_VERSION) { return 1; } assert(ssl->s3->initial_handshake_complete == (ssl->s3->previous_client_finished_len != 0)); 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 && ssl3_protocol_version(ssl) >= TLS1_3_VERSION) { return 0; } /* Servers may not switch between omitting the extension and supporting it. * See RFC 5746, sections 3.5 and 4.2. */ if (ssl->s3->initial_handshake_complete && (contents != NULL) != ssl->s3->send_connection_binding) { *out_alert = SSL_AD_HANDSHAKE_FAILURE; OPENSSL_PUT_ERROR(SSL, SSL_R_RENEGOTIATION_MISMATCH); return 0; } if (contents == NULL) { /* 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. * * OpenSSL has |SSL_OP_LEGACY_SERVER_CONNECT| to control this, but in * practical terms every client sets it so it's just assumed here. */ return 1; } 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); assert(ssl->s3->initial_handshake_complete == (ssl->s3->previous_client_finished_len != 0)); assert(ssl->s3->initial_handshake_complete == (ssl->s3->previous_server_finished_len != 0)); /* 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); if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION) { return 1; } if (contents == NULL) { 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. We do not support renegotiation as a * server, so this must be empty. */ if (CBS_len(&renegotiated_connection) != 0) { 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) { /* Renegotiation isn't supported as a server so this function should never be * called after the initial handshake. */ assert(!ssl->s3->initial_handshake_complete); if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION) { return 1; } if (!CBB_add_u16(out, TLSEXT_TYPE_renegotiate) || !CBB_add_u16(out, 1 /* length */) || !CBB_add_u8(out, 0 /* empty renegotiation info */)) { return 0; } return 1; } /* Extended Master Secret. * * https://tools.ietf.org/html/rfc7627 */ static int ext_ems_add_clienthello(SSL *ssl, CBB *out) { uint16_t min_version, max_version; if (!ssl_get_version_range(ssl, &min_version, &max_version)) { return 0; } /* Extended master secret is not necessary in TLS 1.3. */ if (min_version >= TLS1_3_VERSION || max_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) { /* Whether EMS is negotiated may not change on renegotation. */ if (ssl->s3->initial_handshake_complete) { if ((contents != NULL) != ssl->s3->tmp.extended_master_secret) { OPENSSL_PUT_ERROR(SSL, SSL_R_RENEGOTIATION_EMS_MISMATCH); *out_alert = SSL_AD_ILLEGAL_PARAMETER; return 0; } return 1; } if (contents == NULL) { return 1; } if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION || ssl->version == SSL3_VERSION) { return 0; } if (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 (ssl3_protocol_version(ssl) >= TLS1_3_VERSION || ssl->version == SSL3_VERSION) { return 1; } if (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) { uint16_t min_version, max_version; if (!ssl_get_version_range(ssl, &min_version, &max_version)) { return 0; } /* TLS 1.3 uses a different ticket extension. */ if (min_version >= TLS1_3_VERSION || 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. */ uint16_t session_version; if (!ssl->s3->initial_handshake_complete && ssl->session != NULL && ssl->session->tlsext_tick != NULL && /* Don't send TLS 1.3 session tickets in the ticket extension. */ ssl->method->version_from_wire(&session_version, ssl->session->ssl_version) && session_version < TLS1_3_VERSION) { 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) { if (contents == NULL) { return 1; } if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION) { return 0; } /* 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->s3->hs->ticket_expected = 1; return 1; } static int ext_ticket_add_serverhello(SSL *ssl, CBB *out) { if (!ssl->s3->hs->ticket_expected) { return 1; } /* If |SSL_OP_NO_TICKET| is set, |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) { uint16_t min_version, max_version; if (!ssl_get_version_range(ssl, &min_version, &max_version)) { return 0; } if (max_version < TLS1_2_VERSION) { return 1; } const uint16_t *sigalgs; const size_t num_sigalgs = tls12_get_verify_sigalgs(ssl, &sigalgs); CBB contents, sigalgs_cbb; if (!CBB_add_u16(out, TLSEXT_TYPE_signature_algorithms) || !CBB_add_u16_length_prefixed(out, &contents) || !CBB_add_u16_length_prefixed(&contents, &sigalgs_cbb)) { return 0; } for (size_t i = 0; i < num_sigalgs; i++) { if (!CBB_add_u16(&sigalgs_cbb, sigalgs[i])) { return 0; } } if (!CBB_flush(out)) { return 0; } return 1; } static int ext_sigalgs_parse_clienthello(SSL *ssl, uint8_t *out_alert, CBS *contents) { OPENSSL_free(ssl->s3->hs->peer_sigalgs); ssl->s3->hs->peer_sigalgs = NULL; ssl->s3->hs->num_peer_sigalgs = 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; } /* OCSP Stapling. * * https://tools.ietf.org/html/rfc6066#section-8 */ static void ext_ocsp_init(SSL *ssl) { ssl->tlsext_status_type = -1; } 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; } ssl->tlsext_status_type = TLSEXT_STATUSTYPE_ocsp; return 1; } static int ext_ocsp_parse_serverhello(SSL *ssl, uint8_t *out_alert, CBS *contents) { if (contents == NULL) { return 1; } if (ssl3_protocol_version(ssl) < TLS1_3_VERSION) { /* OCSP stapling is forbidden on non-certificate ciphers. */ if (CBS_len(contents) != 0 || !ssl_cipher_uses_certificate_auth(ssl->s3->tmp.new_cipher)) { return 0; } /* Note this does not check for resumption in TLS 1.2. Sending * status_request here does not make sense, but OpenSSL does so and the * specification does not say anything. Tolerate it but ignore it. */ ssl->s3->hs->certificate_status_expected = 1; return 1; } /* In TLS 1.3, OCSP stapling is forbidden on resumption. */ if (ssl->s3->session_reused) { return 0; } uint8_t status_type; CBS ocsp_response; if (!CBS_get_u8(contents, &status_type) || status_type != TLSEXT_STATUSTYPE_ocsp || !CBS_get_u24_length_prefixed(contents, &ocsp_response) || CBS_len(&ocsp_response) == 0 || CBS_len(contents) != 0) { return 0; } if (!CBS_stow(&ocsp_response, &ssl->s3->new_session->ocsp_response, &ssl->s3->new_session->ocsp_response_length)) { *out_alert = SSL_AD_INTERNAL_ERROR; return 0; } 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->hs->ocsp_stapling_requested = status_type == TLSEXT_STATUSTYPE_ocsp; return 1; } static int ext_ocsp_add_serverhello(SSL *ssl, CBB *out) { if (!ssl->s3->hs->ocsp_stapling_requested || ssl->ctx->ocsp_response_length == 0 || ssl->s3->session_reused || (ssl3_protocol_version(ssl) < TLS1_3_VERSION && !ssl_cipher_uses_certificate_auth(ssl->s3->tmp.new_cipher))) { return 1; } if (ssl3_protocol_version(ssl) < TLS1_3_VERSION) { /* The extension shouldn't be sent when resuming sessions. */ if (ssl->session != NULL) { return 1; } ssl->s3->hs->certificate_status_expected = 1; return CBB_add_u16(out, TLSEXT_TYPE_status_request) && CBB_add_u16(out, 0 /* length */); } CBB body, ocsp_response; return CBB_add_u16(out, TLSEXT_TYPE_status_request) && CBB_add_u16_length_prefixed(out, &body) && CBB_add_u8(&body, TLSEXT_STATUSTYPE_ocsp) && CBB_add_u24_length_prefixed(&body, &ocsp_response) && CBB_add_bytes(&ocsp_response, ssl->ctx->ocsp_response, ssl->ctx->ocsp_response_length) && CBB_flush(out); } /* Next protocol negotiation. * * https://htmlpreview.github.io/?https://github.com/agl/technotes/blob/master/nextprotoneg.html */ static int ext_npn_add_clienthello(SSL *ssl, CBB *out) { if (ssl->s3->initial_handshake_complete || ssl->ctx->next_proto_select_cb == NULL || (ssl->options & SSL_OP_DISABLE_NPN) || 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 (ssl3_protocol_version(ssl) >= TLS1_3_VERSION) { return 0; } /* 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); assert(!(ssl->options & SSL_OP_DISABLE_NPN)); 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->s3->next_proto_negotiated); ssl->s3->next_proto_negotiated = BUF_memdup(selected, selected_len); if (ssl->s3->next_proto_negotiated == NULL) { *out_alert = SSL_AD_INTERNAL_ERROR; return 0; } ssl->s3->next_proto_negotiated_len = selected_len; ssl->s3->hs->next_proto_neg_seen = 1; return 1; } static int ext_npn_parse_clienthello(SSL *ssl, uint8_t *out_alert, CBS *contents) { if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION) { return 1; } if (contents != NULL && CBS_len(contents) != 0) { return 0; } if (contents == NULL || ssl->s3->initial_handshake_complete || ssl->ctx->next_protos_advertised_cb == NULL || SSL_is_dtls(ssl)) { return 1; } ssl->s3->hs->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->hs->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->hs->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. The extension * should not be sent on resumption, but RFC 6962 did not make it a * requirement, so tolerate this. * * TODO(davidben): Enforce this anyway. */ if (!ssl->s3->session_reused && !CBS_stow( contents, &ssl->s3->new_session->tlsext_signed_cert_timestamp_list, &ssl->s3->new_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->s3->session_reused || 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->hs->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; } /* Check that the protcol name is one of the ones we advertised. */ int protocol_ok = 0; CBS client_protocol_name_list, client_protocol_name; CBS_init(&client_protocol_name_list, ssl->alpn_client_proto_list, ssl->alpn_client_proto_list_len); while (CBS_len(&client_protocol_name_list) > 0) { if (!CBS_get_u8_length_prefixed(&client_protocol_name_list, &client_protocol_name)) { *out_alert = SSL_AD_INTERNAL_ERROR; return 0; } if (CBS_len(&client_protocol_name) == CBS_len(&protocol_name) && memcmp(CBS_data(&client_protocol_name), CBS_data(&protocol_name), CBS_len(&protocol_name)) == 0) { protocol_ok = 1; break; } } if (!protocol_ok) { OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_ALPN_PROTOCOL); *out_alert = SSL_AD_ILLEGAL_PARAMETER; 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; } int ssl_negotiate_alpn(SSL *ssl, uint8_t *out_alert, const struct ssl_early_callback_ctx *client_hello) { CBS contents; if (ssl->ctx->alpn_select_cb == NULL || !ssl_early_callback_get_extension( client_hello, &contents, TLSEXT_TYPE_application_layer_protocol_negotiation)) { /* Ignore ALPN if not configured or no extension was supplied. */ return 1; } /* ALPN takes precedence over NPN. */ ssl->s3->hs->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) { OPENSSL_PUT_ERROR(SSL, SSL_R_PARSE_TLSEXT); *out_alert = SSL_AD_DECODE_ERROR; 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) { OPENSSL_PUT_ERROR(SSL, SSL_R_PARSE_TLSEXT); *out_alert = SSL_AD_DECODE_ERROR; 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; } for (size_t 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). */ for (size_t 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. */ for (size_t 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 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) { uint16_t min_version, max_version; if (!ssl_get_version_range(ssl, &min_version, &max_version)) { return 0; } /* The point format extension is unneccessary in TLS 1.3. */ if (min_version >= TLS1_3_VERSION) { 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; } if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION) { return 0; } 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) { if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION) { return 1; } return ext_ec_point_parse_serverhello(ssl, out_alert, contents); } static int ext_ec_point_add_serverhello(SSL *ssl, CBB *out) { if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION) { return 1; } 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); } /* Pre Shared Key * * https://tools.ietf.org/html/draft-ietf-tls-tls13-16#section-4.2.6 */ static int ext_pre_shared_key_add_clienthello(SSL *ssl, CBB *out) { uint16_t min_version, max_version; if (!ssl_get_version_range(ssl, &min_version, &max_version)) { return 0; } uint16_t session_version; if (max_version < TLS1_3_VERSION || ssl->session == NULL || !ssl->method->version_from_wire(&session_version, ssl->session->ssl_version) || session_version < TLS1_3_VERSION) { return 1; } CBB contents, identity, ke_modes, auth_modes, ticket; if (!CBB_add_u16(out, TLSEXT_TYPE_pre_shared_key) || !CBB_add_u16_length_prefixed(out, &contents) || !CBB_add_u16_length_prefixed(&contents, &identity) || !CBB_add_u8_length_prefixed(&identity, &ke_modes) || !CBB_add_u8(&ke_modes, SSL_PSK_DHE_KE) || !CBB_add_u8_length_prefixed(&identity, &auth_modes) || !CBB_add_u8(&auth_modes, SSL_PSK_AUTH) || !CBB_add_u16_length_prefixed(&identity, &ticket) || !CBB_add_bytes(&ticket, ssl->session->tlsext_tick, ssl->session->tlsext_ticklen)) { return 0; } return CBB_flush(out); } int ssl_ext_pre_shared_key_parse_serverhello(SSL *ssl, uint8_t *out_alert, CBS *contents) { uint16_t psk_id; if (!CBS_get_u16(contents, &psk_id) || CBS_len(contents) != 0) { OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); *out_alert = SSL_AD_DECODE_ERROR; return 0; } /* We only advertise one PSK identity, so the only legal index is zero. */ if (psk_id != 0) { OPENSSL_PUT_ERROR(SSL, SSL_R_PSK_IDENTITY_NOT_FOUND); *out_alert = SSL_AD_UNKNOWN_PSK_IDENTITY; return 0; } return 1; } int ssl_ext_pre_shared_key_parse_clienthello(SSL *ssl, SSL_SESSION **out_session, uint8_t *out_alert, CBS *contents) { /* We only process the first PSK identity since we don't support pure PSK. */ CBS identity, ke_modes, auth_modes, ticket; if (!CBS_get_u16_length_prefixed(contents, &identity) || !CBS_get_u8_length_prefixed(&identity, &ke_modes) || !CBS_get_u8_length_prefixed(&identity, &auth_modes) || !CBS_get_u16_length_prefixed(&identity, &ticket) || CBS_len(contents) != 0) { *out_alert = SSL_AD_DECODE_ERROR; return 0; } /* We only support tickets with PSK_DHE_KE and PSK_AUTH. */ if (memchr(CBS_data(&ke_modes), SSL_PSK_DHE_KE, CBS_len(&ke_modes)) == NULL || memchr(CBS_data(&auth_modes), SSL_PSK_AUTH, CBS_len(&auth_modes)) == NULL) { *out_session = NULL; return 1; } /* TLS 1.3 session tickets are renewed separately as part of the * NewSessionTicket. */ int renew; return tls_process_ticket(ssl, out_session, &renew, CBS_data(&ticket), CBS_len(&ticket), NULL, 0); } int ssl_ext_pre_shared_key_add_serverhello(SSL *ssl, CBB *out) { if (!ssl->s3->session_reused) { return 1; } CBB contents; if (!CBB_add_u16(out, TLSEXT_TYPE_pre_shared_key) || !CBB_add_u16_length_prefixed(out, &contents) || /* We only consider the first identity for resumption */ !CBB_add_u16(&contents, 0) || !CBB_flush(out)) { return 0; } return 1; } /* Key Share * * https://tools.ietf.org/html/draft-ietf-tls-tls13-16#section-4.2.5 */ static int ext_key_share_add_clienthello(SSL *ssl, CBB *out) { uint16_t min_version, max_version; if (!ssl_get_version_range(ssl, &min_version, &max_version)) { return 0; } if (max_version < TLS1_3_VERSION) { return 1; } CBB contents, kse_bytes; if (!CBB_add_u16(out, TLSEXT_TYPE_key_share) || !CBB_add_u16_length_prefixed(out, &contents) || !CBB_add_u16_length_prefixed(&contents, &kse_bytes)) { return 0; } uint16_t group_id; if (ssl->s3->hs->received_hello_retry_request) { /* Replay the old key shares. */ if (!CBB_add_bytes(&kse_bytes, ssl->s3->hs->key_share_bytes, ssl->s3->hs->key_share_bytes_len)) { return 0; } OPENSSL_free(ssl->s3->hs->key_share_bytes); ssl->s3->hs->key_share_bytes = NULL; ssl->s3->hs->key_share_bytes_len = 0; group_id = ssl->s3->hs->retry_group; /* We received a HelloRetryRequest without a new curve, so there is no new * share to append. Leave |ecdh_ctx| as-is. */ if (group_id == 0) { return CBB_flush(out); } } else { /* Add a fake group. See draft-davidben-tls-grease-01. */ if (ssl->ctx->grease_enabled && (!CBB_add_u16(&kse_bytes, ssl_get_grease_value(ssl, ssl_grease_group)) || !CBB_add_u16(&kse_bytes, 1 /* length */) || !CBB_add_u8(&kse_bytes, 0 /* one byte key share */))) { return 0; } /* Predict the most preferred group. */ const uint16_t *groups; size_t groups_len; tls1_get_grouplist(ssl, &groups, &groups_len); if (groups_len == 0) { OPENSSL_PUT_ERROR(SSL, SSL_R_NO_GROUPS_SPECIFIED); return 0; } group_id = groups[0]; } CBB key_exchange; if (!CBB_add_u16(&kse_bytes, group_id) || !CBB_add_u16_length_prefixed(&kse_bytes, &key_exchange) || !SSL_ECDH_CTX_init(&ssl->s3->hs->ecdh_ctx, group_id) || !SSL_ECDH_CTX_offer(&ssl->s3->hs->ecdh_ctx, &key_exchange) || !CBB_flush(&kse_bytes)) { return 0; } if (!ssl->s3->hs->received_hello_retry_request) { /* Save the contents of the extension to repeat it in the second * ClientHello. */ ssl->s3->hs->key_share_bytes_len = CBB_len(&kse_bytes); ssl->s3->hs->key_share_bytes = BUF_memdup(CBB_data(&kse_bytes), CBB_len(&kse_bytes)); if (ssl->s3->hs->key_share_bytes == NULL) { return 0; } } return CBB_flush(out); } int ssl_ext_key_share_parse_serverhello(SSL *ssl, uint8_t **out_secret, size_t *out_secret_len, uint8_t *out_alert, CBS *contents) { CBS peer_key; uint16_t group_id; if (!CBS_get_u16(contents, &group_id) || !CBS_get_u16_length_prefixed(contents, &peer_key) || CBS_len(contents) != 0) { *out_alert = SSL_AD_DECODE_ERROR; return 0; } if (SSL_ECDH_CTX_get_id(&ssl->s3->hs->ecdh_ctx) != group_id) { *out_alert = SSL_AD_ILLEGAL_PARAMETER; OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_CURVE); return 0; } if (!SSL_ECDH_CTX_finish(&ssl->s3->hs->ecdh_ctx, out_secret, out_secret_len, out_alert, CBS_data(&peer_key), CBS_len(&peer_key))) { *out_alert = SSL_AD_INTERNAL_ERROR; return 0; } ssl->s3->new_session->key_exchange_info = group_id; SSL_ECDH_CTX_cleanup(&ssl->s3->hs->ecdh_ctx); return 1; } int ssl_ext_key_share_parse_clienthello(SSL *ssl, int *out_found, uint8_t **out_secret, size_t *out_secret_len, uint8_t *out_alert, CBS *contents) { uint16_t group_id; CBS key_shares; if (!tls1_get_shared_group(ssl, &group_id)) { OPENSSL_PUT_ERROR(SSL, SSL_R_NO_SHARED_GROUP); *out_alert = SSL_AD_HANDSHAKE_FAILURE; return 0; } if (!CBS_get_u16_length_prefixed(contents, &key_shares) || CBS_len(contents) != 0) { OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); return 0; } /* Find the corresponding key share. */ int found = 0; CBS peer_key; while (CBS_len(&key_shares) > 0) { uint16_t id; CBS peer_key_tmp; if (!CBS_get_u16(&key_shares, &id) || !CBS_get_u16_length_prefixed(&key_shares, &peer_key_tmp)) { OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); return 0; } if (id == group_id) { if (found) { OPENSSL_PUT_ERROR(SSL, SSL_R_DUPLICATE_KEY_SHARE); *out_alert = SSL_AD_ILLEGAL_PARAMETER; return 0; } found = 1; peer_key = peer_key_tmp; /* Continue parsing the structure to keep peers honest. */ } } if (!found) { *out_found = 0; *out_secret = NULL; *out_secret_len = 0; return 1; } /* Compute the DH secret. */ uint8_t *secret = NULL; size_t secret_len; SSL_ECDH_CTX group; memset(&group, 0, sizeof(SSL_ECDH_CTX)); CBB public_key; if (!CBB_init(&public_key, 32) || !SSL_ECDH_CTX_init(&group, group_id) || !SSL_ECDH_CTX_accept(&group, &public_key, &secret, &secret_len, out_alert, CBS_data(&peer_key), CBS_len(&peer_key)) || !CBB_finish(&public_key, &ssl->s3->hs->public_key, &ssl->s3->hs->public_key_len)) { OPENSSL_free(secret); SSL_ECDH_CTX_cleanup(&group); CBB_cleanup(&public_key); *out_alert = SSL_AD_ILLEGAL_PARAMETER; return 0; } SSL_ECDH_CTX_cleanup(&group); *out_secret = secret; *out_secret_len = secret_len; *out_found = 1; return 1; } int ssl_ext_key_share_add_serverhello(SSL *ssl, CBB *out) { uint16_t group_id; CBB kse_bytes, public_key; if (!tls1_get_shared_group(ssl, &group_id) || !CBB_add_u16(out, TLSEXT_TYPE_key_share) || !CBB_add_u16_length_prefixed(out, &kse_bytes) || !CBB_add_u16(&kse_bytes, group_id) || !CBB_add_u16_length_prefixed(&kse_bytes, &public_key) || !CBB_add_bytes(&public_key, ssl->s3->hs->public_key, ssl->s3->hs->public_key_len) || !CBB_flush(out)) { return 0; } OPENSSL_free(ssl->s3->hs->public_key); ssl->s3->hs->public_key = NULL; ssl->s3->hs->public_key_len = 0; ssl->s3->new_session->key_exchange_info = group_id; return 1; } /* Supported Versions * * https://tools.ietf.org/html/draft-ietf-tls-tls13-16#section-4.2.1 */ static int ext_supported_versions_add_clienthello(SSL *ssl, CBB *out) { uint16_t min_version, max_version; if (!ssl_get_version_range(ssl, &min_version, &max_version)) { return 0; } if (max_version <= TLS1_2_VERSION) { return 1; } CBB contents, versions; if (!CBB_add_u16(out, TLSEXT_TYPE_supported_versions) || !CBB_add_u16_length_prefixed(out, &contents) || !CBB_add_u8_length_prefixed(&contents, &versions)) { return 0; } /* Add a fake version. See draft-davidben-tls-grease-01. */ if (ssl->ctx->grease_enabled && !CBB_add_u16(&versions, ssl_get_grease_value(ssl, ssl_grease_version))) { return 0; } for (uint16_t version = max_version; version >= min_version; version--) { if (!CBB_add_u16(&versions, ssl->method->version_to_wire(version))) { return 0; } } if (!CBB_flush(out)) { return 0; } return 1; } /* Cookie * * https://tools.ietf.org/html/draft-ietf-tls-tls13-16#section-4.2.2 */ static int ext_cookie_add_clienthello(SSL *ssl, CBB *out) { if (ssl->s3->hs->cookie == NULL) { return 1; } CBB contents, cookie; if (!CBB_add_u16(out, TLSEXT_TYPE_cookie) || !CBB_add_u16_length_prefixed(out, &contents) || !CBB_add_u16_length_prefixed(&contents, &cookie) || !CBB_add_bytes(&cookie, ssl->s3->hs->cookie, ssl->s3->hs->cookie_len) || !CBB_flush(out)) { return 0; } /* The cookie is no longer needed in memory. */ OPENSSL_free(ssl->s3->hs->cookie); ssl->s3->hs->cookie = NULL; ssl->s3->hs->cookie_len = 0; return 1; } /* Negotiated Groups * * https://tools.ietf.org/html/rfc4492#section-5.1.2 * https://tools.ietf.org/html/draft-ietf-tls-tls13-16#section-4.2.4 */ static int ext_supported_groups_add_clienthello(SSL *ssl, CBB *out) { CBB contents, groups_bytes; if (!CBB_add_u16(out, TLSEXT_TYPE_supported_groups) || !CBB_add_u16_length_prefixed(out, &contents) || !CBB_add_u16_length_prefixed(&contents, &groups_bytes)) { return 0; } /* Add a fake group. See draft-davidben-tls-grease-01. */ if (ssl->ctx->grease_enabled && !CBB_add_u16(&groups_bytes, ssl_get_grease_value(ssl, ssl_grease_group))) { return 0; } const uint16_t *groups; size_t groups_len; tls1_get_grouplist(ssl, &groups, &groups_len); for (size_t i = 0; i < groups_len; i++) { if (!CBB_add_u16(&groups_bytes, groups[i])) { return 0; } } return CBB_flush(out); } static int ext_supported_groups_parse_serverhello(SSL *ssl, uint8_t *out_alert, CBS *contents) { /* This extension is not expected to be echoed by servers in TLS 1.2, but some * BigIP servers send it nonetheless, so do not enforce this. */ return 1; } static int ext_supported_groups_parse_clienthello(SSL *ssl, uint8_t *out_alert, CBS *contents) { if (contents == NULL) { return 1; } CBS supported_group_list; if (!CBS_get_u16_length_prefixed(contents, &supported_group_list) || CBS_len(&supported_group_list) == 0 || (CBS_len(&supported_group_list) & 1) != 0 || CBS_len(contents) != 0) { return 0; } ssl->s3->hs->peer_supported_group_list = OPENSSL_malloc( CBS_len(&supported_group_list)); if (ssl->s3->hs->peer_supported_group_list == NULL) { *out_alert = SSL_AD_INTERNAL_ERROR; return 0; } const size_t num_groups = CBS_len(&supported_group_list) / 2; for (size_t i = 0; i < num_groups; i++) { if (!CBS_get_u16(&supported_group_list, &ssl->s3->hs->peer_supported_group_list[i])) { goto err; } } assert(CBS_len(&supported_group_list) == 0); ssl->s3->hs->peer_supported_group_list_len = num_groups; return 1; err: OPENSSL_free(ssl->s3->hs->peer_supported_group_list); ssl->s3->hs->peer_supported_group_list = NULL; *out_alert = SSL_AD_INTERNAL_ERROR; return 0; } static int ext_supported_groups_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[] = { { TLSEXT_TYPE_renegotiate, NULL, ext_ri_add_clienthello, ext_ri_parse_serverhello, ext_ri_parse_clienthello, ext_ri_add_serverhello, }, { TLSEXT_TYPE_server_name, NULL, ext_sni_add_clienthello, ext_sni_parse_serverhello, ext_sni_parse_clienthello, ext_sni_add_serverhello, }, { TLSEXT_TYPE_extended_master_secret, NULL, 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, /* Ticket extension client parsing is handled in ssl_session.c */ ignore_parse_clienthello, ext_ticket_add_serverhello, }, { TLSEXT_TYPE_signature_algorithms, NULL, ext_sigalgs_add_clienthello, forbid_parse_serverhello, ext_sigalgs_parse_clienthello, dont_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, NULL, 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, /* ALPN is negotiated late in |ssl_negotiate_alpn|. */ ignore_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_key_share, NULL, ext_key_share_add_clienthello, forbid_parse_serverhello, ignore_parse_clienthello, dont_add_serverhello, }, { TLSEXT_TYPE_pre_shared_key, NULL, ext_pre_shared_key_add_clienthello, forbid_parse_serverhello, ignore_parse_clienthello, dont_add_serverhello, }, { TLSEXT_TYPE_supported_versions, NULL, ext_supported_versions_add_clienthello, forbid_parse_serverhello, ignore_parse_clienthello, dont_add_serverhello, }, { TLSEXT_TYPE_cookie, NULL, ext_cookie_add_clienthello, forbid_parse_serverhello, ignore_parse_clienthello, dont_add_serverhello, }, /* The final extension must be non-empty. WebSphere Application Server 7.0 is * intolerant to the last extension being zero-length. See * https://crbug.com/363583. */ { TLSEXT_TYPE_supported_groups, NULL, ext_supported_groups_add_clienthello, ext_supported_groups_parse_serverhello, ext_supported_groups_parse_clienthello, ext_supported_groups_add_serverhello, }, }; #define kNumExtensions (sizeof(kExtensions) / sizeof(struct tls_extension)) OPENSSL_COMPILE_ASSERT(kNumExtensions <= sizeof(((SSL_HANDSHAKE *)NULL)->extensions.sent) * 8, too_many_extensions_for_sent_bitset); OPENSSL_COMPILE_ASSERT( kNumExtensions <= sizeof(((SSL_HANDSHAKE *)NULL)->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; } CBB extensions; if (!CBB_add_u16_length_prefixed(out, &extensions)) { goto err; } ssl->s3->hs->extensions.sent = 0; ssl->s3->hs->custom_extensions.sent = 0; for (size_t i = 0; i < kNumExtensions; i++) { if (kExtensions[i].init != NULL) { kExtensions[i].init(ssl); } } uint16_t grease_ext1 = 0; if (ssl->ctx->grease_enabled) { /* Add a fake empty extension. See draft-davidben-tls-grease-01. */ grease_ext1 = ssl_get_grease_value(ssl, ssl_grease_extension1); if (!CBB_add_u16(&extensions, grease_ext1) || !CBB_add_u16(&extensions, 0 /* zero length */)) { goto err; } } for (size_t 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->hs->extensions.sent |= (1u << i); } } if (!custom_ext_add_clienthello(ssl, &extensions)) { goto err; } if (ssl->ctx->grease_enabled) { /* Add a fake non-empty extension. See draft-davidben-tls-grease-01. */ uint16_t grease_ext2 = ssl_get_grease_value(ssl, ssl_grease_extension2); /* The two fake extensions must not have the same value. GREASE values are * of the form 0x1a1a, 0x2a2a, 0x3a3a, etc., so XOR to generate a different * one. */ if (grease_ext1 == grease_ext2) { grease_ext2 ^= 0x1010; } if (!CBB_add_u16(&extensions, grease_ext2) || !CBB_add_u16(&extensions, 1 /* one byte length */) || !CBB_add_u8(&extensions, 0 /* single zero byte as contents */)) { goto err; } } if (!SSL_is_dtls(ssl)) { header_len += 2 + CBB_len(&extensions); if (header_len > 0xff && header_len < 0x200) { /* Add padding to workaround bugs in F5 terminators. See RFC 7685. * * 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 at least * one byte of data if including the extension. WebSphere Application * Server 7.0 is intolerant to the last extension being zero-length. See * https://crbug.com/363583. */ 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); } } /* Discard empty extensions blocks. */ if (CBB_len(&extensions) == 0) { CBB_discard_child(out); } return CBB_flush(out); err: OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); return 0; } int ssl_add_serverhello_tlsext(SSL *ssl, CBB *out) { CBB extensions; if (!CBB_add_u16_length_prefixed(out, &extensions)) { goto err; } unsigned i; for (i = 0; i < kNumExtensions; i++) { if (!(ssl->s3->hs->extensions.received & (1u << i))) { /* Don't send extensions that were not received. */ continue; } if (!kExtensions[i].add_serverhello(ssl, &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(ssl, &extensions)) { goto err; } /* Discard empty extensions blocks before TLS 1.3. */ if (ssl3_protocol_version(ssl) < TLS1_3_VERSION && CBB_len(&extensions) == 0) { CBB_discard_child(out); } return CBB_flush(out); err: OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); return 0; } static int ssl_scan_clienthello_tlsext( SSL *ssl, const struct ssl_early_callback_ctx *client_hello, int *out_alert) { for (size_t i = 0; i < kNumExtensions; i++) { if (kExtensions[i].init != NULL) { kExtensions[i].init(ssl); } } ssl->s3->hs->extensions.received = 0; ssl->s3->hs->custom_extensions.received = 0; CBS extensions; CBS_init(&extensions, client_hello->extensions, client_hello->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)) { *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 (ssl->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(ssl, out_alert, type, &extension)) { OPENSSL_PUT_ERROR(SSL, SSL_R_ERROR_PARSING_EXTENSION); return 0; } continue; } ssl->s3->hs->extensions.received |= (1u << ext_index); uint8_t alert = SSL_AD_DECODE_ERROR; if (!ext->parse_clienthello(ssl, &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 (size_t i = 0; i < kNumExtensions; i++) { if (ssl->s3->hs->extensions.received & (1u << i)) { continue; } CBS *contents = NULL, fake_contents; static const uint8_t kFakeRenegotiateExtension[] = {0}; if (kExtensions[i].value == TLSEXT_TYPE_renegotiate && ssl_client_cipher_list_contains_cipher(client_hello, SSL3_CK_SCSV & 0xffff)) { /* The renegotiation SCSV was received so pretend that we received a * renegotiation extension. */ CBS_init(&fake_contents, kFakeRenegotiateExtension, sizeof(kFakeRenegotiateExtension)); contents = &fake_contents; ssl->s3->hs->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(ssl, &alert, contents)) { 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 *ssl, const struct ssl_early_callback_ctx *client_hello) { int alert = -1; if (ssl_scan_clienthello_tlsext(ssl, client_hello, &alert) <= 0) { ssl3_send_alert(ssl, SSL3_AL_FATAL, alert); return 0; } if (ssl_check_clienthello_tlsext(ssl) <= 0) { OPENSSL_PUT_ERROR(SSL, SSL_R_CLIENTHELLO_TLSEXT); return 0; } return 1; } OPENSSL_COMPILE_ASSERT(kNumExtensions <= sizeof(uint32_t) * 8, too_many_bits); static int ssl_scan_serverhello_tlsext(SSL *ssl, CBS *cbs, int *out_alert) { /* Before TLS 1.3, ServerHello extensions blocks may be omitted if empty. */ if (CBS_len(cbs) == 0 && ssl3_protocol_version(ssl) < TLS1_3_VERSION) { return 1; } /* 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; } uint32_t received = 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(ssl, out_alert, type, &extension)) { return 0; } continue; } if (!(ssl->s3->hs->extensions.sent & (1u << ext_index)) && type != TLSEXT_TYPE_renegotiate) { /* If the extension was never sent then it is illegal, except for the * renegotiation extension which, in SSL 3.0, is signaled via SCSV. */ OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_EXTENSION); ERR_add_error_dataf("extension :%u", (unsigned)type); *out_alert = SSL_AD_UNSUPPORTED_EXTENSION; return 0; } received |= (1u << ext_index); uint8_t alert = SSL_AD_DECODE_ERROR; if (!ext->parse_serverhello(ssl, &alert, &extension)) { OPENSSL_PUT_ERROR(SSL, SSL_R_ERROR_PARSING_EXTENSION); ERR_add_error_dataf("extension: %u", (unsigned)type); *out_alert = alert; return 0; } } for (size_t 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(ssl, &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 *ssl) { int ret = SSL_TLSEXT_ERR_NOACK; int al = SSL_AD_UNRECOGNIZED_NAME; if (ssl->ctx->tlsext_servername_callback != 0) { ret = ssl->ctx->tlsext_servername_callback(ssl, &al, ssl->ctx->tlsext_servername_arg); } else if (ssl->initial_ctx->tlsext_servername_callback != 0) { ret = ssl->initial_ctx->tlsext_servername_callback( ssl, &al, ssl->initial_ctx->tlsext_servername_arg); } switch (ret) { case SSL_TLSEXT_ERR_ALERT_FATAL: ssl3_send_alert(ssl, SSL3_AL_FATAL, al); return -1; case SSL_TLSEXT_ERR_ALERT_WARNING: ssl3_send_alert(ssl, SSL3_AL_WARNING, al); return 1; case SSL_TLSEXT_ERR_NOACK: ssl->s3->hs->should_ack_sni = 0; return 1; default: return 1; } } static int ssl_check_serverhello_tlsext(SSL *ssl) { int ret = SSL_TLSEXT_ERR_OK; int al = SSL_AD_UNRECOGNIZED_NAME; if (ssl->ctx->tlsext_servername_callback != 0) { ret = ssl->ctx->tlsext_servername_callback(ssl, &al, ssl->ctx->tlsext_servername_arg); } else if (ssl->initial_ctx->tlsext_servername_callback != 0) { ret = ssl->initial_ctx->tlsext_servername_callback( ssl, &al, ssl->initial_ctx->tlsext_servername_arg); } switch (ret) { case SSL_TLSEXT_ERR_ALERT_FATAL: ssl3_send_alert(ssl, SSL3_AL_FATAL, al); return -1; case SSL_TLSEXT_ERR_ALERT_WARNING: ssl3_send_alert(ssl, SSL3_AL_WARNING, al); return 1; default: return 1; } } int ssl_parse_serverhello_tlsext(SSL *ssl, CBS *cbs) { int alert = -1; if (ssl_scan_serverhello_tlsext(ssl, cbs, &alert) <= 0) { ssl3_send_alert(ssl, SSL3_AL_FATAL, alert); return 0; } if (ssl_check_serverhello_tlsext(ssl) <= 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_renew_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_renew_ticket = 0; *out_session = NULL; if (SSL_get_options(ssl) & SSL_OP_NO_TICKET) { goto done; } if (session_id_len > SSL_MAX_SSL_SESSION_ID_LENGTH) { 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_renew_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); int mac_ok = CRYPTO_memcmp(mac, ticket + (ticket_len - mac_len), mac_len) == 0; #if defined(BORINGSSL_UNSAFE_FUZZER_MODE) mac_ok = 1; #endif if (!mac_ok) { 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; } size_t plaintext_len; #if defined(BORINGSSL_UNSAFE_FUZZER_MODE) memcpy(plaintext, ciphertext, ciphertext_len); plaintext_len = ciphertext_len; #else 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; } plaintext_len = (size_t)(len1 + len2); #endif /* Decode the session. */ SSL_SESSION *session = SSL_SESSION_from_bytes(plaintext, plaintext_len); 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; if (!ssl_session_is_context_valid(ssl, session) || !ssl_session_is_time_valid(ssl, session)) { SSL_SESSION_free(session); session = NULL; } *out_session = session; done: OPENSSL_free(plaintext); HMAC_CTX_cleanup(&hmac_ctx); EVP_CIPHER_CTX_cleanup(&cipher_ctx); return ret; } int tls1_parse_peer_sigalgs(SSL *ssl, const CBS *in_sigalgs) { /* Extension ignored for inappropriate versions */ if (ssl3_protocol_version(ssl) < TLS1_2_VERSION) { return 1; } SSL_HANDSHAKE *hs = ssl->s3->hs; OPENSSL_free(hs->peer_sigalgs); hs->peer_sigalgs = NULL; hs->num_peer_sigalgs = 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(uint16_t) is two * and we just divided |num_sigalgs| by two. */ hs->peer_sigalgs = OPENSSL_malloc(num_sigalgs * sizeof(uint16_t)); if (hs->peer_sigalgs == NULL) { return 0; } hs->num_peer_sigalgs = num_sigalgs; CBS sigalgs; CBS_init(&sigalgs, CBS_data(in_sigalgs), CBS_len(in_sigalgs)); for (size_t i = 0; i < num_sigalgs; i++) { if (!CBS_get_u16(&sigalgs, &hs->peer_sigalgs[i])) { return 0; } } return 1; } int tls1_choose_signature_algorithm(SSL *ssl, uint16_t *out) { CERT *cert = ssl->cert; SSL_HANDSHAKE *hs = ssl->s3->hs; /* Before TLS 1.2, the signature algorithm isn't negotiated as part of the * handshake. It is fixed at MD5-SHA1 for RSA and SHA1 for ECDSA. */ if (ssl3_protocol_version(ssl) < TLS1_2_VERSION) { int type = ssl_private_key_type(ssl); if (type == NID_rsaEncryption) { *out = SSL_SIGN_RSA_PKCS1_MD5_SHA1; return 1; } if (ssl_is_ecdsa_key_type(type)) { *out = SSL_SIGN_ECDSA_SHA1; return 1; } OPENSSL_PUT_ERROR(SSL, SSL_R_NO_COMMON_SIGNATURE_ALGORITHMS); return 0; } const uint16_t *sigalgs = cert->sigalgs; size_t num_sigalgs = cert->num_sigalgs; if (sigalgs == NULL) { sigalgs = kSignSignatureAlgorithms; num_sigalgs = OPENSSL_ARRAY_SIZE(kSignSignatureAlgorithms); } const uint16_t *peer_sigalgs = hs->peer_sigalgs; size_t num_peer_sigalgs = hs->num_peer_sigalgs; if (num_peer_sigalgs == 0 && ssl3_protocol_version(ssl) < TLS1_3_VERSION) { /* If the client didn't specify any signature_algorithms extension then * we can assume that it supports SHA1. See * http://tools.ietf.org/html/rfc5246#section-7.4.1.4.1 */ static const uint16_t kDefaultPeerAlgorithms[] = {SSL_SIGN_RSA_PKCS1_SHA1, SSL_SIGN_ECDSA_SHA1}; peer_sigalgs = kDefaultPeerAlgorithms; num_peer_sigalgs = OPENSSL_ARRAY_SIZE(kDefaultPeerAlgorithms); } for (size_t i = 0; i < num_sigalgs; i++) { uint16_t sigalg = sigalgs[i]; /* SSL_SIGN_RSA_PKCS1_MD5_SHA1 is an internal value and should never be * negotiated. */ if (sigalg == SSL_SIGN_RSA_PKCS1_MD5_SHA1 || !ssl_private_key_supports_signature_algorithm(ssl, sigalgs[i])) { continue; } for (size_t j = 0; j < num_peer_sigalgs; j++) { if (sigalg == peer_sigalgs[j]) { *out = sigalg; return 1; } } } OPENSSL_PUT_ERROR(SSL, SSL_R_NO_COMMON_SIGNATURE_ALGORITHMS); return 0; } int tls1_verify_channel_id(SSL *ssl) { int ret = 0; uint16_t extension_type; CBS extension, channel_id; /* A Channel ID handshake message is structured to contain multiple * extensions, but the only one that can be present is Channel ID. */ CBS_init(&channel_id, ssl->init_msg, ssl->init_num); if (!CBS_get_u16(&channel_id, &extension_type) || !CBS_get_u16_length_prefixed(&channel_id, &extension) || CBS_len(&channel_id) != 0 || extension_type != TLSEXT_TYPE_channel_id || CBS_len(&extension) != TLSEXT_CHANNEL_ID_SIZE) { OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR); ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR); return 0; } EC_GROUP *p256 = EC_GROUP_new_by_curve_name(NID_X9_62_prime256v1); if (!p256) { OPENSSL_PUT_ERROR(SSL, SSL_R_NO_P256_SUPPORT); return 0; } EC_KEY *key = NULL; EC_POINT *point = NULL; BIGNUM x, y; ECDSA_SIG sig; BN_init(&x); BN_init(&y); sig.r = BN_new(); sig.s = BN_new(); if (sig.r == NULL || sig.s == NULL) { goto err; } const uint8_t *p = CBS_data(&extension); if (BN_bin2bn(p + 0, 32, &x) == NULL || BN_bin2bn(p + 32, 32, &y) == NULL || BN_bin2bn(p + 64, 32, sig.r) == NULL || BN_bin2bn(p + 96, 32, sig.s) == NULL) { goto err; } point = EC_POINT_new(p256); if (point == NULL || !EC_POINT_set_affine_coordinates_GFp(p256, point, &x, &y, NULL)) { goto err; } key = EC_KEY_new(); if (key == NULL || !EC_KEY_set_group(key, p256) || !EC_KEY_set_public_key(key, point)) { goto err; } uint8_t digest[EVP_MAX_MD_SIZE]; size_t digest_len; if (!tls1_channel_id_hash(ssl, digest, &digest_len)) { goto err; } int sig_ok = ECDSA_do_verify(digest, digest_len, &sig, key); #if defined(BORINGSSL_UNSAFE_FUZZER_MODE) sig_ok = 1; #endif if (!sig_ok) { OPENSSL_PUT_ERROR(SSL, SSL_R_CHANNEL_ID_SIGNATURE_INVALID); ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECRYPT_ERROR); ssl->s3->tlsext_channel_id_valid = 0; goto err; } memcpy(ssl->s3->tlsext_channel_id, p, 64); ret = 1; err: BN_free(&x); BN_free(&y); BN_free(sig.r); BN_free(sig.s); EC_KEY_free(key); EC_POINT_free(point); EC_GROUP_free(p256); return ret; } int tls1_write_channel_id(SSL *ssl, CBB *cbb) { uint8_t digest[EVP_MAX_MD_SIZE]; size_t digest_len; if (!tls1_channel_id_hash(ssl, digest, &digest_len)) { return 0; } EC_KEY *ec_key = EVP_PKEY_get0_EC_KEY(ssl->tlsext_channel_id_private); if (ec_key == NULL) { OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); return 0; } int ret = 0; BIGNUM *x = BN_new(); BIGNUM *y = BN_new(); ECDSA_SIG *sig = NULL; if (x == NULL || y == NULL || !EC_POINT_get_affine_coordinates_GFp(EC_KEY_get0_group(ec_key), EC_KEY_get0_public_key(ec_key), x, y, NULL)) { goto err; } sig = ECDSA_do_sign(digest, digest_len, ec_key); if (sig == NULL) { goto err; } CBB child; if (!CBB_add_u16(cbb, TLSEXT_TYPE_channel_id) || !CBB_add_u16_length_prefixed(cbb, &child) || !BN_bn2cbb_padded(&child, 32, x) || !BN_bn2cbb_padded(&child, 32, y) || !BN_bn2cbb_padded(&child, 32, sig->r) || !BN_bn2cbb_padded(&child, 32, sig->s) || !CBB_flush(cbb)) { goto err; } ret = 1; err: BN_free(x); BN_free(y); ECDSA_SIG_free(sig); return ret; } int tls1_channel_id_hash(SSL *ssl, uint8_t *out, size_t *out_len) { if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION) { uint8_t *msg; size_t msg_len; if (!tls13_get_cert_verify_signature_input(ssl, &msg, &msg_len, ssl_cert_verify_channel_id)) { return 0; } SHA256(msg, msg_len, out); *out_len = SHA256_DIGEST_LENGTH; OPENSSL_free(msg); return 1; } SHA256_CTX ctx; SHA256_Init(&ctx); static const char kClientIDMagic[] = "TLS Channel ID signature"; SHA256_Update(&ctx, kClientIDMagic, sizeof(kClientIDMagic)); if (ssl->session != NULL) { static const char kResumptionMagic[] = "Resumption"; SHA256_Update(&ctx, kResumptionMagic, sizeof(kResumptionMagic)); if (ssl->session->original_handshake_hash_len == 0) { OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); return 0; } SHA256_Update(&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) { return 0; } SHA256_Update(&ctx, handshake_hash, (size_t)handshake_hash_len); SHA256_Final(out, &ctx); *out_len = SHA256_DIGEST_LENGTH; return 1; } /* tls1_record_handshake_hashes_for_channel_id records the current handshake * hashes in |ssl->s3->new_session| so that Channel ID resumptions can sign that * data. */ int tls1_record_handshake_hashes_for_channel_id(SSL *ssl) { 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 (ssl->session != NULL) { return -1; } digest_len = tls1_handshake_digest( ssl, ssl->s3->new_session->original_handshake_hash, sizeof(ssl->s3->new_session->original_handshake_hash)); if (digest_len < 0) { return -1; } ssl->s3->new_session->original_handshake_hash_len = digest_len; return 1; } int ssl_do_channel_id_callback(SSL *ssl) { if (ssl->tlsext_channel_id_private != NULL || ssl->ctx->channel_id_cb == NULL) { return 1; } EVP_PKEY *key = NULL; ssl->ctx->channel_id_cb(ssl, &key); if (key == NULL) { /* The caller should try again later. */ return 1; } int ret = SSL_set1_tls_channel_id(ssl, key); EVP_PKEY_free(key); return ret; }