--- /dev/null
+/* 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 <openssl/ssl.h>
+
+#include <assert.h>
+#include <limits.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <utility>
+
+#include <openssl/bytestring.h>
+#include <openssl/chacha.h>
+#include <openssl/digest.h>
+#include <openssl/err.h>
+#include <openssl/evp.h>
+#include <openssl/hmac.h>
+#include <openssl/mem.h>
+#include <openssl/nid.h>
+#include <openssl/rand.h>
+
+#include "internal.h"
+#include "../crypto/internal.h"
+
+
+namespace bssl {
+
+static int ssl_check_clienthello_tlsext(SSL_HANDSHAKE *hs);
+
+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) {
+ // First pass: count the extensions.
+ size_t num_extensions = 0;
+ CBS extensions = *cbs;
+ while (CBS_len(&extensions) > 0) {
+ uint16_t type;
+ CBS extension;
+
+ if (!CBS_get_u16(&extensions, &type) ||
+ !CBS_get_u16_length_prefixed(&extensions, &extension)) {
+ return 0;
+ }
+
+ num_extensions++;
+ }
+
+ if (num_extensions == 0) {
+ return 1;
+ }
+
+ Array<uint16_t> extension_types;
+ if (!extension_types.Init(num_extensions)) {
+ return 0;
+ }
+
+ // Second pass: gather the extension types.
+ extensions = *cbs;
+ for (size_t i = 0; i < extension_types.size(); i++) {
+ CBS extension;
+
+ if (!CBS_get_u16(&extensions, &extension_types[i]) ||
+ !CBS_get_u16_length_prefixed(&extensions, &extension)) {
+ // This should not happen.
+ return 0;
+ }
+ }
+ assert(CBS_len(&extensions) == 0);
+
+ // Sort the extensions and make sure there are no duplicates.
+ qsort(extension_types.data(), extension_types.size(), sizeof(uint16_t),
+ compare_uint16_t);
+ for (size_t i = 1; i < num_extensions; i++) {
+ if (extension_types[i - 1] == extension_types[i]) {
+ return 0;
+ }
+ }
+
+ return 1;
+}
+
+int ssl_client_hello_init(SSL *ssl, SSL_CLIENT_HELLO *out,
+ const SSLMessage &msg) {
+ OPENSSL_memset(out, 0, sizeof(*out));
+ out->ssl = ssl;
+ out->client_hello = CBS_data(&msg.body);
+ out->client_hello_len = CBS_len(&msg.body);
+
+ CBS client_hello, random, session_id;
+ CBS_init(&client_hello, out->client_hello, out->client_hello_len);
+ if (!CBS_get_u16(&client_hello, &out->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;
+ }
+
+ out->random = CBS_data(&random);
+ out->random_len = CBS_len(&random);
+ out->session_id = CBS_data(&session_id);
+ out->session_id_len = CBS_len(&session_id);
+
+ // Skip past DTLS cookie
+ if (SSL_is_dtls(out->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;
+ }
+
+ out->cipher_suites = CBS_data(&cipher_suites);
+ out->cipher_suites_len = CBS_len(&cipher_suites);
+ out->compression_methods = CBS_data(&compression_methods);
+ out->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) {
+ out->extensions = NULL;
+ out->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;
+ }
+
+ out->extensions = CBS_data(&extensions);
+ out->extensions_len = CBS_len(&extensions);
+
+ return 1;
+}
+
+int ssl_client_hello_get_extension(const SSL_CLIENT_HELLO *client_hello,
+ CBS *out, uint16_t extension_type) {
+ CBS extensions;
+ CBS_init(&extensions, client_hello->extensions, client_hello->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;
+}
+
+static const uint16_t kDefaultGroups[] = {
+ SSL_CURVE_X25519,
+ SSL_CURVE_SECP256R1,
+ SSL_CURVE_SECP384R1,
+};
+
+Span<const uint16_t> tls1_get_grouplist(const SSL *ssl) {
+ if (ssl->supported_group_list != nullptr) {
+ return MakeConstSpan(ssl->supported_group_list,
+ ssl->supported_group_list_len);
+ }
+ return Span<const uint16_t>(kDefaultGroups);
+}
+
+int tls1_get_shared_group(SSL_HANDSHAKE *hs, uint16_t *out_group_id) {
+ SSL *const ssl = hs->ssl;
+ assert(ssl->server);
+
+ // 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|.
+
+ Span<const uint16_t> groups = tls1_get_grouplist(ssl);
+ Span<const uint16_t> pref, supp;
+ if (ssl->options & SSL_OP_CIPHER_SERVER_PREFERENCE) {
+ pref = groups;
+ supp = hs->peer_supported_group_list;
+ } else {
+ pref = hs->peer_supported_group_list;
+ supp = groups;
+ }
+
+ for (uint16_t pref_group : pref) {
+ for (uint16_t supp_group : supp) {
+ if (pref_group == supp_group) {
+ *out_group_id = pref_group;
+ 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 = (uint16_t *)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 = (uint16_t *)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(const SSL *ssl, uint16_t group_id) {
+ for (uint16_t supported : tls1_get_grouplist(ssl)) {
+ if (supported == 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[] = {
+ // List our preferred algorithms first.
+ SSL_SIGN_ED25519,
+ SSL_SIGN_ECDSA_SECP256R1_SHA256,
+ SSL_SIGN_RSA_PSS_SHA256,
+ SSL_SIGN_RSA_PKCS1_SHA256,
+
+ // Larger hashes are acceptable.
+ SSL_SIGN_ECDSA_SECP384R1_SHA384,
+ SSL_SIGN_RSA_PSS_SHA384,
+ SSL_SIGN_RSA_PKCS1_SHA384,
+
+ SSL_SIGN_RSA_PSS_SHA512,
+ 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[] = {
+ // List our preferred algorithms first.
+ SSL_SIGN_ED25519,
+ SSL_SIGN_ECDSA_SECP256R1_SHA256,
+ SSL_SIGN_RSA_PSS_SHA256,
+ SSL_SIGN_RSA_PKCS1_SHA256,
+
+ // If needed, sign larger hashes.
+ //
+ // TODO(davidben): Determine which of these may be pruned.
+ SSL_SIGN_ECDSA_SECP384R1_SHA384,
+ SSL_SIGN_RSA_PSS_SHA384,
+ SSL_SIGN_RSA_PKCS1_SHA384,
+
+ SSL_SIGN_ECDSA_SECP521R1_SHA512,
+ SSL_SIGN_RSA_PSS_SHA512,
+ SSL_SIGN_RSA_PKCS1_SHA512,
+
+ // If the peer supports nothing else, sign with SHA-1.
+ SSL_SIGN_ECDSA_SHA1,
+ SSL_SIGN_RSA_PKCS1_SHA1,
+};
+
+bool tls12_add_verify_sigalgs(const SSL *ssl, CBB *out) {
+ bool use_default = ssl->ctx->num_verify_sigalgs == 0;
+ Span<const uint16_t> sigalgs = kVerifySignatureAlgorithms;
+ if (!use_default) {
+ sigalgs = MakeConstSpan(ssl->ctx->verify_sigalgs,
+ ssl->ctx->num_verify_sigalgs);
+ }
+
+ for (uint16_t sigalg : sigalgs) {
+ if (use_default &&
+ sigalg == SSL_SIGN_ED25519 &&
+ !ssl->ctx->ed25519_enabled) {
+ continue;
+ }
+ if (!CBB_add_u16(out, sigalg)) {
+ return false;
+ }
+ }
+
+ return true;
+}
+
+bool tls12_check_peer_sigalg(const SSL *ssl, uint8_t *out_alert,
+ uint16_t sigalg) {
+ const uint16_t *sigalgs = kVerifySignatureAlgorithms;
+ size_t num_sigalgs = OPENSSL_ARRAY_SIZE(kVerifySignatureAlgorithms);
+ if (ssl->ctx->num_verify_sigalgs != 0) {
+ sigalgs = ssl->ctx->verify_sigalgs;
+ num_sigalgs = ssl->ctx->num_verify_sigalgs;
+ }
+
+ for (size_t i = 0; i < num_sigalgs; i++) {
+ if (sigalgs == kVerifySignatureAlgorithms &&
+ sigalgs[i] == SSL_SIGN_ED25519 &&
+ !ssl->ctx->ed25519_enabled) {
+ continue;
+ }
+ if (sigalg == sigalgs[i]) {
+ return true;
+ }
+ }
+
+ OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_SIGNATURE_TYPE);
+ *out_alert = SSL_AD_ILLEGAL_PARAMETER;
+ return false;
+}
+
+// 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 true for success and false 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_HANDSHAKE *hs);
+
+ bool (*add_clienthello)(SSL_HANDSHAKE *hs, CBB *out);
+ bool (*parse_serverhello)(SSL_HANDSHAKE *hs, uint8_t *out_alert,
+ CBS *contents);
+
+ bool (*parse_clienthello)(SSL_HANDSHAKE *hs, uint8_t *out_alert,
+ CBS *contents);
+ bool (*add_serverhello)(SSL_HANDSHAKE *hs, CBB *out);
+};
+
+static bool forbid_parse_serverhello(SSL_HANDSHAKE *hs, 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 false;
+ }
+
+ return true;
+}
+
+static bool ignore_parse_clienthello(SSL_HANDSHAKE *hs, uint8_t *out_alert,
+ CBS *contents) {
+ // This extension from the client is handled elsewhere.
+ return true;
+}
+
+static bool dont_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) {
+ return true;
+}
+
+// Server name indication (SNI).
+//
+// https://tools.ietf.org/html/rfc6066#section-3.
+
+static bool ext_sni_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) {
+ SSL *const ssl = hs->ssl;
+ if (ssl->tlsext_hostname == NULL) {
+ return true;
+ }
+
+ 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 false;
+ }
+
+ return true;
+}
+
+static bool ext_sni_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t *out_alert,
+ CBS *contents) {
+ // The server may acknowledge SNI with an empty extension. We check the syntax
+ // but otherwise ignore this signal.
+ return contents == NULL || CBS_len(contents) == 0;
+}
+
+static bool ext_sni_parse_clienthello(SSL_HANDSHAKE *hs, uint8_t *out_alert,
+ CBS *contents) {
+ SSL *const ssl = hs->ssl;
+ if (contents == NULL) {
+ return true;
+ }
+
+ 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 false;
+ }
+
+ 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 false;
+ }
+
+ // Copy the hostname as a string.
+ char *raw = nullptr;
+ if (!CBS_strdup(&host_name, &raw)) {
+ *out_alert = SSL_AD_INTERNAL_ERROR;
+ return false;
+ }
+ ssl->s3->hostname.reset(raw);
+
+ hs->should_ack_sni = true;
+ return true;
+}
+
+static bool ext_sni_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) {
+ if (hs->ssl->s3->session_reused ||
+ !hs->should_ack_sni) {
+ return true;
+ }
+
+ if (!CBB_add_u16(out, TLSEXT_TYPE_server_name) ||
+ !CBB_add_u16(out, 0 /* length */)) {
+ return false;
+ }
+
+ return true;
+}
+
+
+// Renegotiation indication.
+//
+// https://tools.ietf.org/html/rfc5746
+
+static bool ext_ri_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) {
+ SSL *const ssl = hs->ssl;
+ // Renegotiation indication is not necessary in TLS 1.3.
+ if (hs->min_version >= TLS1_3_VERSION) {
+ return true;
+ }
+
+ 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 false;
+ }
+
+ return true;
+}
+
+static bool ext_ri_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t *out_alert,
+ CBS *contents) {
+ SSL *const ssl = hs->ssl;
+ if (contents != NULL && ssl_protocol_version(ssl) >= TLS1_3_VERSION) {
+ *out_alert = SSL_AD_ILLEGAL_PARAMETER;
+ return false;
+ }
+
+ // 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 false;
+ }
+
+ 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 true;
+ }
+
+ 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 false;
+ }
+
+ // 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 false;
+ }
+
+ const uint8_t *d = CBS_data(&renegotiated_connection);
+ bool ok = CRYPTO_memcmp(d, ssl->s3->previous_client_finished,
+ ssl->s3->previous_client_finished_len) == 0;
+#if defined(BORINGSSL_UNSAFE_FUZZER_MODE)
+ ok = true;
+#endif
+ if (!ok) {
+ OPENSSL_PUT_ERROR(SSL, SSL_R_RENEGOTIATION_MISMATCH);
+ *out_alert = SSL_AD_HANDSHAKE_FAILURE;
+ return false;
+ }
+ d += ssl->s3->previous_client_finished_len;
+
+ ok = CRYPTO_memcmp(d, ssl->s3->previous_server_finished,
+ ssl->s3->previous_server_finished_len) == 0;
+#if defined(BORINGSSL_UNSAFE_FUZZER_MODE)
+ ok = true;
+#endif
+ if (!ok) {
+ OPENSSL_PUT_ERROR(SSL, SSL_R_RENEGOTIATION_MISMATCH);
+ *out_alert = SSL_AD_HANDSHAKE_FAILURE;
+ return false;
+ }
+ ssl->s3->send_connection_binding = true;
+
+ return true;
+}
+
+static bool ext_ri_parse_clienthello(SSL_HANDSHAKE *hs, uint8_t *out_alert,
+ CBS *contents) {
+ SSL *const ssl = hs->ssl;
+ // 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 (ssl_protocol_version(ssl) >= TLS1_3_VERSION) {
+ return true;
+ }
+
+ if (contents == NULL) {
+ return true;
+ }
+
+ 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 false;
+ }
+
+ // 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 false;
+ }
+
+ ssl->s3->send_connection_binding = true;
+
+ return true;
+}
+
+static bool ext_ri_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) {
+ SSL *const ssl = hs->ssl;
+ // 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 (ssl_protocol_version(ssl) >= TLS1_3_VERSION) {
+ return true;
+ }
+
+ if (!CBB_add_u16(out, TLSEXT_TYPE_renegotiate) ||
+ !CBB_add_u16(out, 1 /* length */) ||
+ !CBB_add_u8(out, 0 /* empty renegotiation info */)) {
+ return false;
+ }
+
+ return true;
+}
+
+
+// Extended Master Secret.
+//
+// https://tools.ietf.org/html/rfc7627
+
+static bool ext_ems_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) {
+ // Extended master secret is not necessary in TLS 1.3.
+ if (hs->min_version >= TLS1_3_VERSION || hs->max_version <= SSL3_VERSION) {
+ return true;
+ }
+
+ if (!CBB_add_u16(out, TLSEXT_TYPE_extended_master_secret) ||
+ !CBB_add_u16(out, 0 /* length */)) {
+ return false;
+ }
+
+ return true;
+}
+
+static bool ext_ems_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t *out_alert,
+ CBS *contents) {
+ SSL *const ssl = hs->ssl;
+
+ if (contents != NULL) {
+ if (ssl_protocol_version(ssl) >= TLS1_3_VERSION ||
+ ssl->version == SSL3_VERSION ||
+ CBS_len(contents) != 0) {
+ return false;
+ }
+
+ hs->extended_master_secret = true;
+ }
+
+ // Whether EMS is negotiated may not change on renegotiation.
+ if (ssl->s3->established_session != nullptr &&
+ hs->extended_master_secret !=
+ !!ssl->s3->established_session->extended_master_secret) {
+ OPENSSL_PUT_ERROR(SSL, SSL_R_RENEGOTIATION_EMS_MISMATCH);
+ *out_alert = SSL_AD_ILLEGAL_PARAMETER;
+ return false;
+ }
+
+ return true;
+}
+
+static bool ext_ems_parse_clienthello(SSL_HANDSHAKE *hs, uint8_t *out_alert,
+ CBS *contents) {
+ uint16_t version = ssl_protocol_version(hs->ssl);
+ if (version >= TLS1_3_VERSION ||
+ version == SSL3_VERSION) {
+ return true;
+ }
+
+ if (contents == NULL) {
+ return true;
+ }
+
+ if (CBS_len(contents) != 0) {
+ return false;
+ }
+
+ hs->extended_master_secret = true;
+ return true;
+}
+
+static bool ext_ems_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) {
+ if (!hs->extended_master_secret) {
+ return true;
+ }
+
+ if (!CBB_add_u16(out, TLSEXT_TYPE_extended_master_secret) ||
+ !CBB_add_u16(out, 0 /* length */)) {
+ return false;
+ }
+
+ return true;
+}
+
+
+// Session tickets.
+//
+// https://tools.ietf.org/html/rfc5077
+
+static bool ext_ticket_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) {
+ SSL *const ssl = hs->ssl;
+ // TLS 1.3 uses a different ticket extension.
+ if (hs->min_version >= TLS1_3_VERSION ||
+ SSL_get_options(ssl) & SSL_OP_NO_TICKET) {
+ return true;
+ }
+
+ 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 &&
+ // Don't send TLS 1.3 session tickets in the ticket extension.
+ ssl_session_protocol_version(ssl->session) < 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 false;
+ }
+
+ return true;
+}
+
+static bool ext_ticket_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t *out_alert,
+ CBS *contents) {
+ SSL *const ssl = hs->ssl;
+ if (contents == NULL) {
+ return true;
+ }
+
+ if (ssl_protocol_version(ssl) >= TLS1_3_VERSION) {
+ return false;
+ }
+
+ // 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 false;
+ }
+
+ hs->ticket_expected = true;
+ return true;
+}
+
+static bool ext_ticket_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) {
+ if (!hs->ticket_expected) {
+ return true;
+ }
+
+ // If |SSL_OP_NO_TICKET| is set, |ticket_expected| should never be true.
+ assert((SSL_get_options(hs->ssl) & SSL_OP_NO_TICKET) == 0);
+
+ if (!CBB_add_u16(out, TLSEXT_TYPE_session_ticket) ||
+ !CBB_add_u16(out, 0 /* length */)) {
+ return false;
+ }
+
+ return true;
+}
+
+
+// Signature Algorithms.
+//
+// https://tools.ietf.org/html/rfc5246#section-7.4.1.4.1
+
+static bool ext_sigalgs_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) {
+ SSL *const ssl = hs->ssl;
+ if (hs->max_version < TLS1_2_VERSION) {
+ return true;
+ }
+
+ 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) ||
+ !tls12_add_verify_sigalgs(ssl, &sigalgs_cbb) ||
+ !CBB_flush(out)) {
+ return false;
+ }
+
+ return true;
+}
+
+static bool ext_sigalgs_parse_clienthello(SSL_HANDSHAKE *hs, uint8_t *out_alert,
+ CBS *contents) {
+ hs->peer_sigalgs.Reset();
+ if (contents == NULL) {
+ return true;
+ }
+
+ 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(hs, &supported_signature_algorithms)) {
+ return false;
+ }
+
+ return true;
+}
+
+
+// OCSP Stapling.
+//
+// https://tools.ietf.org/html/rfc6066#section-8
+
+static bool ext_ocsp_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) {
+ SSL *const ssl = hs->ssl;
+ if (!ssl->ocsp_stapling_enabled) {
+ return true;
+ }
+
+ 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 false;
+ }
+
+ return true;
+}
+
+static bool ext_ocsp_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t *out_alert,
+ CBS *contents) {
+ SSL *const ssl = hs->ssl;
+ if (contents == NULL) {
+ return true;
+ }
+
+ // TLS 1.3 OCSP responses are included in the Certificate extensions.
+ if (ssl_protocol_version(ssl) >= TLS1_3_VERSION) {
+ return false;
+ }
+
+ // OCSP stapling is forbidden on non-certificate ciphers.
+ if (CBS_len(contents) != 0 ||
+ !ssl_cipher_uses_certificate_auth(hs->new_cipher)) {
+ return false;
+ }
+
+ // 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.
+
+ hs->certificate_status_expected = true;
+ return true;
+}
+
+static bool ext_ocsp_parse_clienthello(SSL_HANDSHAKE *hs, uint8_t *out_alert,
+ CBS *contents) {
+ if (contents == NULL) {
+ return true;
+ }
+
+ uint8_t status_type;
+ if (!CBS_get_u8(contents, &status_type)) {
+ return false;
+ }
+
+ // We cannot decide whether OCSP stapling will occur yet because the correct
+ // SSL_CTX might not have been selected.
+ hs->ocsp_stapling_requested = status_type == TLSEXT_STATUSTYPE_ocsp;
+
+ return true;
+}
+
+static bool ext_ocsp_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) {
+ SSL *const ssl = hs->ssl;
+ if (ssl_protocol_version(ssl) >= TLS1_3_VERSION ||
+ !hs->ocsp_stapling_requested ||
+ ssl->cert->ocsp_response == NULL ||
+ ssl->s3->session_reused ||
+ !ssl_cipher_uses_certificate_auth(hs->new_cipher)) {
+ return true;
+ }
+
+ hs->certificate_status_expected = true;
+
+ 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 bool ext_npn_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) {
+ SSL *const ssl = hs->ssl;
+ if (ssl->s3->initial_handshake_complete ||
+ ssl->ctx->next_proto_select_cb == NULL ||
+ SSL_is_dtls(ssl)) {
+ return true;
+ }
+
+ if (!CBB_add_u16(out, TLSEXT_TYPE_next_proto_neg) ||
+ !CBB_add_u16(out, 0 /* length */)) {
+ return false;
+ }
+
+ return true;
+}
+
+static bool ext_npn_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t *out_alert,
+ CBS *contents) {
+ SSL *const ssl = hs->ssl;
+ if (contents == NULL) {
+ return true;
+ }
+
+ if (ssl_protocol_version(ssl) >= TLS1_3_VERSION) {
+ return false;
+ }
+
+ // 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.empty()) {
+ // 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 false;
+ }
+
+ 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 false;
+ }
+ }
+
+ 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 ||
+ !ssl->s3->next_proto_negotiated.CopyFrom(
+ MakeConstSpan(selected, selected_len))) {
+ *out_alert = SSL_AD_INTERNAL_ERROR;
+ return false;
+ }
+
+ hs->next_proto_neg_seen = true;
+ return true;
+}
+
+static bool ext_npn_parse_clienthello(SSL_HANDSHAKE *hs, uint8_t *out_alert,
+ CBS *contents) {
+ SSL *const ssl = hs->ssl;
+ if (ssl_protocol_version(ssl) >= TLS1_3_VERSION) {
+ return true;
+ }
+
+ if (contents != NULL && CBS_len(contents) != 0) {
+ return false;
+ }
+
+ if (contents == NULL ||
+ ssl->s3->initial_handshake_complete ||
+ ssl->ctx->next_protos_advertised_cb == NULL ||
+ SSL_is_dtls(ssl)) {
+ return true;
+ }
+
+ hs->next_proto_neg_seen = true;
+ return true;
+}
+
+static bool ext_npn_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) {
+ SSL *const ssl = hs->ssl;
+ // |next_proto_neg_seen| might have been cleared when an ALPN extension was
+ // parsed.
+ if (!hs->next_proto_neg_seen) {
+ return true;
+ }
+
+ 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) {
+ hs->next_proto_neg_seen = false;
+ return true;
+ }
+
+ 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 false;
+ }
+
+ return true;
+}
+
+
+// Signed certificate timestamps.
+//
+// https://tools.ietf.org/html/rfc6962#section-3.3.1
+
+static bool ext_sct_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) {
+ SSL *const ssl = hs->ssl;
+ if (!ssl->signed_cert_timestamps_enabled) {
+ return true;
+ }
+
+ if (!CBB_add_u16(out, TLSEXT_TYPE_certificate_timestamp) ||
+ !CBB_add_u16(out, 0 /* length */)) {
+ return false;
+ }
+
+ return true;
+}
+
+static bool ext_sct_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t *out_alert,
+ CBS *contents) {
+ SSL *const ssl = hs->ssl;
+ if (contents == NULL) {
+ return true;
+ }
+
+ // TLS 1.3 SCTs are included in the Certificate extensions.
+ if (ssl_protocol_version(ssl) >= TLS1_3_VERSION) {
+ *out_alert = SSL_AD_DECODE_ERROR;
+ return false;
+ }
+
+ // 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 (!ssl_is_sct_list_valid(contents)) {
+ *out_alert = SSL_AD_DECODE_ERROR;
+ return false;
+ }
+
+ // 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) {
+ CRYPTO_BUFFER_free(hs->new_session->signed_cert_timestamp_list);
+ hs->new_session->signed_cert_timestamp_list =
+ CRYPTO_BUFFER_new_from_CBS(contents, ssl->ctx->pool);
+ if (hs->new_session->signed_cert_timestamp_list == nullptr) {
+ *out_alert = SSL_AD_INTERNAL_ERROR;
+ return false;
+ }
+ }
+
+ return true;
+}
+
+static bool ext_sct_parse_clienthello(SSL_HANDSHAKE *hs, uint8_t *out_alert,
+ CBS *contents) {
+ if (contents == NULL) {
+ return true;
+ }
+
+ if (CBS_len(contents) != 0) {
+ return false;
+ }
+
+ hs->scts_requested = true;
+ return true;
+}
+
+static bool ext_sct_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) {
+ SSL *const ssl = hs->ssl;
+ // The extension shouldn't be sent when resuming sessions.
+ if (ssl_protocol_version(ssl) >= TLS1_3_VERSION ||
+ ssl->s3->session_reused ||
+ ssl->cert->signed_cert_timestamp_list == NULL) {
+ return true;
+ }
+
+ CBB contents;
+ return CBB_add_u16(out, TLSEXT_TYPE_certificate_timestamp) &&
+ CBB_add_u16_length_prefixed(out, &contents) &&
+ CBB_add_bytes(
+ &contents,
+ CRYPTO_BUFFER_data(ssl->cert->signed_cert_timestamp_list),
+ CRYPTO_BUFFER_len(ssl->cert->signed_cert_timestamp_list)) &&
+ CBB_flush(out);
+}
+
+
+// Application-level Protocol Negotiation.
+//
+// https://tools.ietf.org/html/rfc7301
+
+static bool ext_alpn_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) {
+ SSL *const ssl = hs->ssl;
+ if (ssl->alpn_client_proto_list == NULL ||
+ ssl->s3->initial_handshake_complete) {
+ return true;
+ }
+
+ 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 false;
+ }
+
+ return true;
+}
+
+static bool ext_alpn_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t *out_alert,
+ CBS *contents) {
+ SSL *const ssl = hs->ssl;
+ if (contents == NULL) {
+ return true;
+ }
+
+ assert(!ssl->s3->initial_handshake_complete);
+ assert(ssl->alpn_client_proto_list != NULL);
+
+ if (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 false;
+ }
+
+ // 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 false;
+ }
+
+ if (!ssl_is_alpn_protocol_allowed(ssl, protocol_name)) {
+ OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_ALPN_PROTOCOL);
+ *out_alert = SSL_AD_ILLEGAL_PARAMETER;
+ return false;
+ }
+
+ if (!ssl->s3->alpn_selected.CopyFrom(protocol_name)) {
+ *out_alert = SSL_AD_INTERNAL_ERROR;
+ return false;
+ }
+
+ return true;
+}
+
+bool ssl_is_alpn_protocol_allowed(const SSL *ssl,
+ Span<const uint8_t> protocol) {
+ if (ssl->alpn_client_proto_list == nullptr) {
+ return false;
+ }
+
+ if (ssl->ctx->allow_unknown_alpn_protos) {
+ return true;
+ }
+
+ // Check that the protocol name is one of the ones we advertised.
+ 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)) {
+ return false;
+ }
+
+ if (client_protocol_name == protocol) {
+ return true;
+ }
+ }
+
+ return false;
+}
+
+bool ssl_negotiate_alpn(SSL_HANDSHAKE *hs, uint8_t *out_alert,
+ const SSL_CLIENT_HELLO *client_hello) {
+ SSL *const ssl = hs->ssl;
+ CBS contents;
+ if (ssl->ctx->alpn_select_cb == NULL ||
+ !ssl_client_hello_get_extension(
+ client_hello, &contents,
+ TLSEXT_TYPE_application_layer_protocol_negotiation)) {
+ // Ignore ALPN if not configured or no extension was supplied.
+ return true;
+ }
+
+ // ALPN takes precedence over NPN.
+ hs->next_proto_neg_seen = false;
+
+ 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 false;
+ }
+
+ // 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 false;
+ }
+ }
+
+ 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) {
+ if (!ssl->s3->alpn_selected.CopyFrom(
+ MakeConstSpan(selected, selected_len))) {
+ *out_alert = SSL_AD_INTERNAL_ERROR;
+ return false;
+ }
+ }
+
+ return true;
+}
+
+static bool ext_alpn_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) {
+ SSL *const ssl = hs->ssl;
+ if (ssl->s3->alpn_selected.empty()) {
+ return true;
+ }
+
+ 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.data(),
+ ssl->s3->alpn_selected.size()) ||
+ !CBB_flush(out)) {
+ return false;
+ }
+
+ return true;
+}
+
+
+// Channel ID.
+//
+// https://tools.ietf.org/html/draft-balfanz-tls-channelid-01
+
+static void ext_channel_id_init(SSL_HANDSHAKE *hs) {
+ hs->ssl->s3->tlsext_channel_id_valid = false;
+}
+
+static bool ext_channel_id_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) {
+ SSL *const ssl = hs->ssl;
+ if (!ssl->tlsext_channel_id_enabled ||
+ SSL_is_dtls(ssl)) {
+ return true;
+ }
+
+ if (!CBB_add_u16(out, TLSEXT_TYPE_channel_id) ||
+ !CBB_add_u16(out, 0 /* length */)) {
+ return false;
+ }
+
+ return true;
+}
+
+static bool ext_channel_id_parse_serverhello(SSL_HANDSHAKE *hs,
+ uint8_t *out_alert,
+ CBS *contents) {
+ SSL *const ssl = hs->ssl;
+ if (contents == NULL) {
+ return true;
+ }
+
+ assert(!SSL_is_dtls(ssl));
+ assert(ssl->tlsext_channel_id_enabled);
+
+ if (CBS_len(contents) != 0) {
+ return false;
+ }
+
+ ssl->s3->tlsext_channel_id_valid = true;
+ return true;
+}
+
+static bool ext_channel_id_parse_clienthello(SSL_HANDSHAKE *hs,
+ uint8_t *out_alert,
+ CBS *contents) {
+ SSL *const ssl = hs->ssl;
+ if (contents == NULL ||
+ !ssl->tlsext_channel_id_enabled ||
+ SSL_is_dtls(ssl)) {
+ return true;
+ }
+
+ if (CBS_len(contents) != 0) {
+ return false;
+ }
+
+ ssl->s3->tlsext_channel_id_valid = true;
+ return true;
+}
+
+static bool ext_channel_id_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) {
+ SSL *const ssl = hs->ssl;
+ if (!ssl->s3->tlsext_channel_id_valid) {
+ return true;
+ }
+
+ if (!CBB_add_u16(out, TLSEXT_TYPE_channel_id) ||
+ !CBB_add_u16(out, 0 /* length */)) {
+ return false;
+ }
+
+ return true;
+}
+
+
+// Secure Real-time Transport Protocol (SRTP) extension.
+//
+// https://tools.ietf.org/html/rfc5764
+
+
+static void ext_srtp_init(SSL_HANDSHAKE *hs) {
+ hs->ssl->srtp_profile = NULL;
+}
+
+static bool ext_srtp_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) {
+ SSL *const ssl = hs->ssl;
+ STACK_OF(SRTP_PROTECTION_PROFILE) *profiles = SSL_get_srtp_profiles(ssl);
+ if (profiles == NULL ||
+ sk_SRTP_PROTECTION_PROFILE_num(profiles) == 0) {
+ return true;
+ }
+
+ 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 false;
+ }
+
+ for (const SRTP_PROTECTION_PROFILE *profile : profiles) {
+ if (!CBB_add_u16(&profile_ids, profile->id)) {
+ return false;
+ }
+ }
+
+ if (!CBB_add_u8(&contents, 0 /* empty use_mki value */) ||
+ !CBB_flush(out)) {
+ return false;
+ }
+
+ return true;
+}
+
+static bool ext_srtp_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t *out_alert,
+ CBS *contents) {
+ SSL *const ssl = hs->ssl;
+ if (contents == NULL) {
+ return true;
+ }
+
+ // 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 false;
+ }
+
+ 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 false;
+ }
+
+ 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 (const SRTP_PROTECTION_PROFILE *profile : profiles) {
+ if (profile->id == profile_id) {
+ ssl->srtp_profile = profile;
+ return true;
+ }
+ }
+
+ OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
+ *out_alert = SSL_AD_ILLEGAL_PARAMETER;
+ return false;
+}
+
+static bool ext_srtp_parse_clienthello(SSL_HANDSHAKE *hs, uint8_t *out_alert,
+ CBS *contents) {
+ SSL *const ssl = hs->ssl;
+ if (contents == NULL) {
+ return true;
+ }
+
+ 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 false;
+ }
+ // 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 (const SRTP_PROTECTION_PROFILE *server_profile : server_profiles) {
+ 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 false;
+ }
+
+ if (server_profile->id == profile_id) {
+ ssl->srtp_profile = server_profile;
+ return true;
+ }
+ }
+ }
+
+ return true;
+}
+
+static bool ext_srtp_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) {
+ SSL *const ssl = hs->ssl;
+ if (ssl->srtp_profile == NULL) {
+ return true;
+ }
+
+ 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 false;
+ }
+
+ return true;
+}
+
+
+// EC point formats.
+//
+// https://tools.ietf.org/html/rfc4492#section-5.1.2
+
+static bool ext_ec_point_add_extension(SSL_HANDSHAKE *hs, 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 false;
+ }
+
+ return true;
+}
+
+static bool ext_ec_point_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) {
+ // The point format extension is unneccessary in TLS 1.3.
+ if (hs->min_version >= TLS1_3_VERSION) {
+ return true;
+ }
+
+ return ext_ec_point_add_extension(hs, out);
+}
+
+static bool ext_ec_point_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t *out_alert,
+ CBS *contents) {
+ if (contents == NULL) {
+ return true;
+ }
+
+ if (ssl_protocol_version(hs->ssl) >= TLS1_3_VERSION) {
+ return false;
+ }
+
+ CBS ec_point_format_list;
+ if (!CBS_get_u8_length_prefixed(contents, &ec_point_format_list) ||
+ CBS_len(contents) != 0) {
+ return false;
+ }
+
+ // Per RFC 4492, section 5.1.2, implementations MUST support the uncompressed
+ // point format.
+ if (OPENSSL_memchr(CBS_data(&ec_point_format_list),
+ TLSEXT_ECPOINTFORMAT_uncompressed,
+ CBS_len(&ec_point_format_list)) == NULL) {
+ *out_alert = SSL_AD_ILLEGAL_PARAMETER;
+ return false;
+ }
+
+ return true;
+}
+
+static bool ext_ec_point_parse_clienthello(SSL_HANDSHAKE *hs, uint8_t *out_alert,
+ CBS *contents) {
+ if (ssl_protocol_version(hs->ssl) >= TLS1_3_VERSION) {
+ return true;
+ }
+
+ return ext_ec_point_parse_serverhello(hs, out_alert, contents);
+}
+
+static bool ext_ec_point_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) {
+ SSL *const ssl = hs->ssl;
+ if (ssl_protocol_version(ssl) >= TLS1_3_VERSION) {
+ return true;
+ }
+
+ const uint32_t alg_k = hs->new_cipher->algorithm_mkey;
+ const uint32_t alg_a = hs->new_cipher->algorithm_auth;
+ const bool using_ecc = (alg_k & SSL_kECDHE) || (alg_a & SSL_aECDSA);
+
+ if (!using_ecc) {
+ return true;
+ }
+
+ return ext_ec_point_add_extension(hs, out);
+}
+
+
+// Pre Shared Key
+//
+// https://tools.ietf.org/html/draft-ietf-tls-tls13-18#section-4.2.6
+
+static size_t ext_pre_shared_key_clienthello_length(SSL_HANDSHAKE *hs) {
+ SSL *const ssl = hs->ssl;
+ if (hs->max_version < TLS1_3_VERSION || ssl->session == NULL ||
+ ssl_session_protocol_version(ssl->session) < TLS1_3_VERSION) {
+ return 0;
+ }
+
+ size_t binder_len = EVP_MD_size(ssl_session_get_digest(ssl->session));
+ return 15 + ssl->session->tlsext_ticklen + binder_len;
+}
+
+static bool ext_pre_shared_key_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) {
+ SSL *const ssl = hs->ssl;
+ hs->needs_psk_binder = false;
+ if (hs->max_version < TLS1_3_VERSION || ssl->session == NULL ||
+ ssl_session_protocol_version(ssl->session) < TLS1_3_VERSION) {
+ return true;
+ }
+
+ // Per draft-ietf-tls-tls13-21 section 4.1.4, skip offering the session if the
+ // selected cipher in HelloRetryRequest does not match. This avoids performing
+ // the transcript hash transformation for multiple hashes.
+ if (hs->received_hello_retry_request &&
+ ssl->session->cipher->algorithm_prf != hs->new_cipher->algorithm_prf) {
+ return true;
+ }
+
+ struct OPENSSL_timeval now;
+ ssl_get_current_time(ssl, &now);
+ uint32_t ticket_age = 1000 * (now.tv_sec - ssl->session->time);
+ uint32_t obfuscated_ticket_age = ticket_age + ssl->session->ticket_age_add;
+
+ // Fill in a placeholder zero binder of the appropriate length. It will be
+ // computed and filled in later after length prefixes are computed.
+ uint8_t zero_binder[EVP_MAX_MD_SIZE] = {0};
+ size_t binder_len = EVP_MD_size(ssl_session_get_digest(ssl->session));
+
+ CBB contents, identity, ticket, binders, binder;
+ 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_u16_length_prefixed(&identity, &ticket) ||
+ !CBB_add_bytes(&ticket, ssl->session->tlsext_tick,
+ ssl->session->tlsext_ticklen) ||
+ !CBB_add_u32(&identity, obfuscated_ticket_age) ||
+ !CBB_add_u16_length_prefixed(&contents, &binders) ||
+ !CBB_add_u8_length_prefixed(&binders, &binder) ||
+ !CBB_add_bytes(&binder, zero_binder, binder_len)) {
+ return false;
+ }
+
+ hs->needs_psk_binder = true;
+ return CBB_flush(out);
+}
+
+bool ssl_ext_pre_shared_key_parse_serverhello(SSL_HANDSHAKE *hs,
+ 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 false;
+ }
+
+ // 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 false;
+ }
+
+ return true;
+}
+
+bool ssl_ext_pre_shared_key_parse_clienthello(
+ SSL_HANDSHAKE *hs, CBS *out_ticket, CBS *out_binders,
+ uint32_t *out_obfuscated_ticket_age, uint8_t *out_alert, CBS *contents) {
+ // We only process the first PSK identity since we don't support pure PSK.
+ CBS identities, binders;
+ if (!CBS_get_u16_length_prefixed(contents, &identities) ||
+ !CBS_get_u16_length_prefixed(&identities, out_ticket) ||
+ !CBS_get_u32(&identities, out_obfuscated_ticket_age) ||
+ !CBS_get_u16_length_prefixed(contents, &binders) ||
+ CBS_len(&binders) == 0 ||
+ CBS_len(contents) != 0) {
+ OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
+ *out_alert = SSL_AD_DECODE_ERROR;
+ return false;
+ }
+
+ *out_binders = binders;
+
+ // Check the syntax of the remaining identities, but do not process them.
+ size_t num_identities = 1;
+ while (CBS_len(&identities) != 0) {
+ CBS unused_ticket;
+ uint32_t unused_obfuscated_ticket_age;
+ if (!CBS_get_u16_length_prefixed(&identities, &unused_ticket) ||
+ !CBS_get_u32(&identities, &unused_obfuscated_ticket_age)) {
+ OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
+ *out_alert = SSL_AD_DECODE_ERROR;
+ return false;
+ }
+
+ num_identities++;
+ }
+
+ // Check the syntax of the binders. The value will be checked later if
+ // resuming.
+ size_t num_binders = 0;
+ while (CBS_len(&binders) != 0) {
+ CBS binder;
+ if (!CBS_get_u8_length_prefixed(&binders, &binder)) {
+ OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
+ *out_alert = SSL_AD_DECODE_ERROR;
+ return false;
+ }
+
+ num_binders++;
+ }
+
+ if (num_identities != num_binders) {
+ OPENSSL_PUT_ERROR(SSL, SSL_R_PSK_IDENTITY_BINDER_COUNT_MISMATCH);
+ *out_alert = SSL_AD_ILLEGAL_PARAMETER;
+ return false;
+ }
+
+ return true;
+}
+
+bool ssl_ext_pre_shared_key_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) {
+ if (!hs->ssl->s3->session_reused) {
+ return true;
+ }
+
+ 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 false;
+ }
+
+ return true;
+}
+
+
+// Pre-Shared Key Exchange Modes
+//
+// https://tools.ietf.org/html/draft-ietf-tls-tls13-18#section-4.2.7
+
+static bool ext_psk_key_exchange_modes_add_clienthello(SSL_HANDSHAKE *hs,
+ CBB *out) {
+ if (hs->max_version < TLS1_3_VERSION) {
+ return true;
+ }
+
+ CBB contents, ke_modes;
+ if (!CBB_add_u16(out, TLSEXT_TYPE_psk_key_exchange_modes) ||
+ !CBB_add_u16_length_prefixed(out, &contents) ||
+ !CBB_add_u8_length_prefixed(&contents, &ke_modes) ||
+ !CBB_add_u8(&ke_modes, SSL_PSK_DHE_KE)) {
+ return false;
+ }
+
+ return CBB_flush(out);
+}
+
+static bool ext_psk_key_exchange_modes_parse_clienthello(SSL_HANDSHAKE *hs,
+ uint8_t *out_alert,
+ CBS *contents) {
+ if (contents == NULL) {
+ return true;
+ }
+
+ CBS ke_modes;
+ if (!CBS_get_u8_length_prefixed(contents, &ke_modes) ||
+ CBS_len(&ke_modes) == 0 ||
+ CBS_len(contents) != 0) {
+ *out_alert = SSL_AD_DECODE_ERROR;
+ return false;
+ }
+
+ // We only support tickets with PSK_DHE_KE.
+ hs->accept_psk_mode = OPENSSL_memchr(CBS_data(&ke_modes), SSL_PSK_DHE_KE,
+ CBS_len(&ke_modes)) != NULL;
+
+ return true;
+}
+
+
+// Early Data Indication
+//
+// https://tools.ietf.org/html/draft-ietf-tls-tls13-18#section-4.2.8
+
+static bool ext_early_data_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) {
+ SSL *const ssl = hs->ssl;
+ if (!ssl->cert->enable_early_data ||
+ // Session must be 0-RTT capable.
+ ssl->session == NULL ||
+ ssl_session_protocol_version(ssl->session) < TLS1_3_VERSION ||
+ ssl->session->ticket_max_early_data == 0 ||
+ // The second ClientHello never offers early data.
+ hs->received_hello_retry_request ||
+ // In case ALPN preferences changed since this session was established,
+ // avoid reporting a confusing value in |SSL_get0_alpn_selected|.
+ (ssl->session->early_alpn_len != 0 &&
+ !ssl_is_alpn_protocol_allowed(
+ ssl, MakeConstSpan(ssl->session->early_alpn,
+ ssl->session->early_alpn_len)))) {
+ return true;
+ }
+
+ hs->early_data_offered = true;
+
+ if (!CBB_add_u16(out, TLSEXT_TYPE_early_data) ||
+ !CBB_add_u16(out, 0) ||
+ !CBB_flush(out)) {
+ return false;
+ }
+
+ return true;
+}
+
+static bool ext_early_data_parse_serverhello(SSL_HANDSHAKE *hs,
+ uint8_t *out_alert, CBS *contents) {
+ SSL *const ssl = hs->ssl;
+ if (contents == NULL) {
+ return true;
+ }
+
+ if (CBS_len(contents) != 0) {
+ *out_alert = SSL_AD_DECODE_ERROR;
+ return false;
+ }
+
+ if (!ssl->s3->session_reused) {
+ *out_alert = SSL_AD_UNSUPPORTED_EXTENSION;
+ OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_EXTENSION);
+ return false;
+ }
+
+ ssl->s3->early_data_accepted = true;
+ return true;
+}
+
+static bool ext_early_data_parse_clienthello(SSL_HANDSHAKE *hs,
+ uint8_t *out_alert, CBS *contents) {
+ SSL *const ssl = hs->ssl;
+ if (contents == NULL ||
+ ssl_protocol_version(ssl) < TLS1_3_VERSION) {
+ return true;
+ }
+
+ if (CBS_len(contents) != 0) {
+ *out_alert = SSL_AD_DECODE_ERROR;
+ return false;
+ }
+
+ hs->early_data_offered = true;
+ return true;
+}
+
+static bool ext_early_data_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) {
+ if (!hs->ssl->s3->early_data_accepted) {
+ return true;
+ }
+
+ if (!CBB_add_u16(out, TLSEXT_TYPE_early_data) ||
+ !CBB_add_u16(out, 0) ||
+ !CBB_flush(out)) {
+ return false;
+ }
+
+ return true;
+}
+
+
+// Key Share
+//
+// https://tools.ietf.org/html/draft-ietf-tls-tls13-16#section-4.2.5
+
+static bool ext_key_share_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) {
+ SSL *const ssl = hs->ssl;
+ if (hs->max_version < TLS1_3_VERSION) {
+ return true;
+ }
+
+ 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 false;
+ }
+
+ uint16_t group_id = hs->retry_group;
+ if (hs->received_hello_retry_request) {
+ // We received a HelloRetryRequest without a new curve, so there is no new
+ // share to append. Leave |hs->key_share| as-is.
+ if (group_id == 0 &&
+ !CBB_add_bytes(&kse_bytes, hs->key_share_bytes.data(),
+ hs->key_share_bytes.size())) {
+ return false;
+ }
+ hs->key_share_bytes.Reset();
+ 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(hs, ssl_grease_group)) ||
+ !CBB_add_u16(&kse_bytes, 1 /* length */) ||
+ !CBB_add_u8(&kse_bytes, 0 /* one byte key share */))) {
+ return false;
+ }
+
+ // Predict the most preferred group.
+ Span<const uint16_t> groups = tls1_get_grouplist(ssl);
+ if (groups.empty()) {
+ OPENSSL_PUT_ERROR(SSL, SSL_R_NO_GROUPS_SPECIFIED);
+ return false;
+ }
+
+ group_id = groups[0];
+ }
+
+ hs->key_share = SSLKeyShare::Create(group_id);
+ CBB key_exchange;
+ if (!hs->key_share ||
+ !CBB_add_u16(&kse_bytes, group_id) ||
+ !CBB_add_u16_length_prefixed(&kse_bytes, &key_exchange) ||
+ !hs->key_share->Offer(&key_exchange) ||
+ !CBB_flush(&kse_bytes)) {
+ return false;
+ }
+
+ // Save the contents of the extension to repeat it in the second ClientHello.
+ if (!hs->received_hello_retry_request &&
+ !hs->key_share_bytes.CopyFrom(
+ MakeConstSpan(CBB_data(&kse_bytes), CBB_len(&kse_bytes)))) {
+ return false;
+ }
+
+ return CBB_flush(out);
+}
+
+bool ssl_ext_key_share_parse_serverhello(SSL_HANDSHAKE *hs,
+ Array<uint8_t> *out_secret,
+ 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) {
+ OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
+ *out_alert = SSL_AD_DECODE_ERROR;
+ return false;
+ }
+
+ if (hs->key_share->GroupID() != group_id) {
+ *out_alert = SSL_AD_ILLEGAL_PARAMETER;
+ OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_CURVE);
+ return false;
+ }
+
+ if (!hs->key_share->Finish(out_secret, out_alert, peer_key)) {
+ *out_alert = SSL_AD_INTERNAL_ERROR;
+ return false;
+ }
+
+ hs->new_session->group_id = group_id;
+ hs->key_share.reset();
+ return true;
+}
+
+bool ssl_ext_key_share_parse_clienthello(SSL_HANDSHAKE *hs, bool *out_found,
+ Array<uint8_t> *out_secret,
+ uint8_t *out_alert, CBS *contents) {
+ uint16_t group_id;
+ CBS key_shares;
+ if (!tls1_get_shared_group(hs, &group_id)) {
+ OPENSSL_PUT_ERROR(SSL, SSL_R_NO_SHARED_GROUP);
+ *out_alert = SSL_AD_HANDSHAKE_FAILURE;
+ return false;
+ }
+
+ if (!CBS_get_u16_length_prefixed(contents, &key_shares) ||
+ CBS_len(contents) != 0) {
+ OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
+ return false;
+ }
+
+ // Find the corresponding key share.
+ CBS peer_key;
+ CBS_init(&peer_key, NULL, 0);
+ 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) ||
+ CBS_len(&peer_key_tmp) == 0) {
+ OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
+ return false;
+ }
+
+ if (id == group_id) {
+ if (CBS_len(&peer_key) != 0) {
+ OPENSSL_PUT_ERROR(SSL, SSL_R_DUPLICATE_KEY_SHARE);
+ *out_alert = SSL_AD_ILLEGAL_PARAMETER;
+ return false;
+ }
+
+ peer_key = peer_key_tmp;
+ // Continue parsing the structure to keep peers honest.
+ }
+ }
+
+ if (CBS_len(&peer_key) == 0) {
+ *out_found = false;
+ out_secret->Reset();
+ return true;
+ }
+
+ // Compute the DH secret.
+ Array<uint8_t> secret;
+ ScopedCBB public_key;
+ UniquePtr<SSLKeyShare> key_share = SSLKeyShare::Create(group_id);
+ if (!key_share ||
+ !CBB_init(public_key.get(), 32) ||
+ !key_share->Accept(public_key.get(), &secret, out_alert, peer_key) ||
+ !CBBFinishArray(public_key.get(), &hs->ecdh_public_key)) {
+ *out_alert = SSL_AD_ILLEGAL_PARAMETER;
+ return false;
+ }
+
+ *out_secret = std::move(secret);
+ *out_found = true;
+ return true;
+}
+
+bool ssl_ext_key_share_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) {
+ uint16_t group_id;
+ CBB kse_bytes, public_key;
+ if (!tls1_get_shared_group(hs, &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, hs->ecdh_public_key.data(),
+ hs->ecdh_public_key.size()) ||
+ !CBB_flush(out)) {
+ return false;
+ }
+
+ hs->ecdh_public_key.Reset();
+
+ hs->new_session->group_id = group_id;
+ return true;
+}
+
+
+// Supported Versions
+//
+// https://tools.ietf.org/html/draft-ietf-tls-tls13-16#section-4.2.1
+
+static bool ext_supported_versions_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) {
+ SSL *const ssl = hs->ssl;
+ if (hs->max_version <= TLS1_2_VERSION) {
+ return true;
+ }
+
+ 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 false;
+ }
+
+ // Add a fake version. See draft-davidben-tls-grease-01.
+ if (ssl->ctx->grease_enabled &&
+ !CBB_add_u16(&versions, ssl_get_grease_value(hs, ssl_grease_version))) {
+ return false;
+ }
+
+ if (!ssl_add_supported_versions(hs, &versions) ||
+ !CBB_flush(out)) {
+ return false;
+ }
+
+ return true;
+}
+
+
+// Cookie
+//
+// https://tools.ietf.org/html/draft-ietf-tls-tls13-16#section-4.2.2
+
+static bool ext_cookie_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) {
+ if (hs->cookie.empty()) {
+ return true;
+ }
+
+ 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, hs->cookie.data(), hs->cookie.size()) ||
+ !CBB_flush(out)) {
+ return false;
+ }
+
+ // The cookie is no longer needed in memory.
+ hs->cookie.Reset();
+ return true;
+}
+
+
+// Dummy PQ Padding extension
+//
+// Dummy post-quantum padding invovles the client (and later server) sending
+// useless, random-looking bytes in an extension in their ClientHello or
+// ServerHello. These extensions are sized to simulate a post-quantum
+// key-exchange and so enable measurement of the latency impact of the
+// additional bandwidth.
+
+static bool ext_dummy_pq_padding_add(CBB *out, size_t len) {
+ CBB contents;
+ uint8_t *buffer;
+ if (!CBB_add_u16(out, TLSEXT_TYPE_dummy_pq_padding) ||
+ !CBB_add_u16_length_prefixed(out, &contents) ||
+ !CBB_add_space(&contents, &buffer, len)) {
+ return false;
+ }
+
+ // The length is used as the nonce so that different length extensions have
+ // different contents. There's no reason this has to be the case, it just
+ // makes things a little more obvious in a packet dump.
+ uint8_t nonce[12] = {0};
+ memcpy(nonce, &len, sizeof(len));
+
+ memset(buffer, 0, len);
+ static const uint8_t kZeroKey[32] = {0};
+ CRYPTO_chacha_20(buffer, buffer, len, kZeroKey, nonce, 0);
+
+ return CBB_flush(out);
+}
+
+static bool ext_dummy_pq_padding_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) {
+ const size_t len = hs->ssl->dummy_pq_padding_len;
+ if (len == 0) {
+ return true;
+ }
+
+ return ext_dummy_pq_padding_add(out, len);
+}
+
+static bool ext_dummy_pq_padding_parse_serverhello(SSL_HANDSHAKE *hs,
+ uint8_t *out_alert,
+ CBS *contents) {
+ if (contents == nullptr) {
+ return true;
+ }
+
+ if (CBS_len(contents) != hs->ssl->dummy_pq_padding_len) {
+ return false;
+ }
+
+ hs->ssl->did_dummy_pq_padding = true;
+ return true;
+}
+
+static bool ext_dummy_pq_padding_parse_clienthello(SSL_HANDSHAKE *hs,
+ uint8_t *out_alert,
+ CBS *contents) {
+ if (contents != nullptr &&
+ 0 < CBS_len(contents) && CBS_len(contents) < (1 << 12)) {
+ hs->dummy_pq_padding_len = CBS_len(contents);
+ }
+
+ return true;
+}
+
+static bool ext_dummy_pq_padding_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) {
+ if (!hs->dummy_pq_padding_len) {
+ return true;
+ }
+
+ return ext_dummy_pq_padding_add(out, hs->dummy_pq_padding_len);
+}
+
+// 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 bool ext_supported_groups_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) {
+ SSL *const ssl = hs->ssl;
+ 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 false;
+ }
+
+ // Add a fake group. See draft-davidben-tls-grease-01.
+ if (ssl->ctx->grease_enabled &&
+ !CBB_add_u16(&groups_bytes,
+ ssl_get_grease_value(hs, ssl_grease_group))) {
+ return false;
+ }
+
+ for (uint16_t group : tls1_get_grouplist(ssl)) {
+ if (!CBB_add_u16(&groups_bytes, group)) {
+ return false;
+ }
+ }
+
+ return CBB_flush(out);
+}
+
+static bool ext_supported_groups_parse_serverhello(SSL_HANDSHAKE *hs,
+ 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 true;
+}
+
+static bool parse_u16_array(const CBS *cbs, Array<uint16_t> *out) {
+ CBS copy = *cbs;
+ if ((CBS_len(©) & 1) != 0) {
+ OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
+ return false;
+ }
+
+ Array<uint16_t> ret;
+ if (!ret.Init(CBS_len(©) / 2)) {
+ return false;
+ }
+ for (size_t i = 0; i < ret.size(); i++) {
+ if (!CBS_get_u16(©, &ret[i])) {
+ OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
+ return false;
+ }
+ }
+
+ assert(CBS_len(©) == 0);
+ *out = std::move(ret);
+ return 1;
+}
+
+static bool ext_supported_groups_parse_clienthello(SSL_HANDSHAKE *hs,
+ uint8_t *out_alert,
+ CBS *contents) {
+ if (contents == NULL) {
+ return true;
+ }
+
+ CBS supported_group_list;
+ if (!CBS_get_u16_length_prefixed(contents, &supported_group_list) ||
+ CBS_len(&supported_group_list) == 0 ||
+ CBS_len(contents) != 0 ||
+ !parse_u16_array(&supported_group_list, &hs->peer_supported_group_list)) {
+ return false;
+ }
+
+ return true;
+}
+
+// Token Binding
+//
+// https://tools.ietf.org/html/draft-ietf-tokbind-negotiation-10
+
+// The Token Binding version number currently matches the draft number of
+// draft-ietf-tokbind-protocol, and when published as an RFC it will be 0x0100.
+// Since there are no wire changes to the protocol from draft 13 through the
+// current draft (16), this implementation supports all versions in that range.
+static uint16_t kTokenBindingMaxVersion = 16;
+static uint16_t kTokenBindingMinVersion = 13;
+
+static bool ext_token_binding_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) {
+ SSL *const ssl = hs->ssl;
+ if (ssl->token_binding_params == nullptr || SSL_is_dtls(ssl)) {
+ return true;
+ }
+
+ CBB contents, params;
+ if (!CBB_add_u16(out, TLSEXT_TYPE_token_binding) ||
+ !CBB_add_u16_length_prefixed(out, &contents) ||
+ !CBB_add_u16(&contents, kTokenBindingMaxVersion) ||
+ !CBB_add_u8_length_prefixed(&contents, ¶ms) ||
+ !CBB_add_bytes(¶ms, ssl->token_binding_params,
+ ssl->token_binding_params_len) ||
+ !CBB_flush(out)) {
+ return false;
+ }
+
+ return true;
+}
+
+static bool ext_token_binding_parse_serverhello(SSL_HANDSHAKE *hs,
+ uint8_t *out_alert,
+ CBS *contents) {
+ SSL *const ssl = hs->ssl;
+ if (contents == nullptr) {
+ return true;
+ }
+
+ CBS params_list;
+ uint16_t version;
+ uint8_t param;
+ if (!CBS_get_u16(contents, &version) ||
+ !CBS_get_u8_length_prefixed(contents, ¶ms_list) ||
+ !CBS_get_u8(¶ms_list, ¶m) ||
+ CBS_len(¶ms_list) > 0 ||
+ CBS_len(contents) > 0) {
+ *out_alert = SSL_AD_DECODE_ERROR;
+ return false;
+ }
+
+ // The server-negotiated version must be less than or equal to our version.
+ if (version > kTokenBindingMaxVersion) {
+ *out_alert = SSL_AD_ILLEGAL_PARAMETER;
+ return false;
+ }
+
+ // If the server-selected version is less than what we support, then Token
+ // Binding wasn't negotiated (but the extension was parsed successfully).
+ if (version < kTokenBindingMinVersion) {
+ return true;
+ }
+
+ for (size_t i = 0; i < ssl->token_binding_params_len; ++i) {
+ if (param == ssl->token_binding_params[i]) {
+ ssl->negotiated_token_binding_param = param;
+ ssl->token_binding_negotiated = true;
+ return true;
+ }
+ }
+
+ *out_alert = SSL_AD_ILLEGAL_PARAMETER;
+ return false;
+}
+
+// select_tb_param looks for the first token binding param in
+// |ssl->token_binding_params| that is also in |params| and puts it in
+// |ssl->negotiated_token_binding_param|. It returns true if a token binding
+// param is found, and false otherwise.
+static bool select_tb_param(SSL *ssl, Span<const uint8_t> peer_params) {
+ for (size_t i = 0; i < ssl->token_binding_params_len; ++i) {
+ uint8_t tb_param = ssl->token_binding_params[i];
+ for (uint8_t peer_param : peer_params) {
+ if (tb_param == peer_param) {
+ ssl->negotiated_token_binding_param = tb_param;
+ return true;
+ }
+ }
+ }
+ return false;
+}
+
+static bool ext_token_binding_parse_clienthello(SSL_HANDSHAKE *hs,
+ uint8_t *out_alert,
+ CBS *contents) {
+ SSL *const ssl = hs->ssl;
+ if (contents == nullptr || ssl->token_binding_params == nullptr) {
+ return true;
+ }
+
+ CBS params;
+ uint16_t version;
+ if (!CBS_get_u16(contents, &version) ||
+ !CBS_get_u8_length_prefixed(contents, ¶ms) ||
+ CBS_len(¶ms) == 0 ||
+ CBS_len(contents) > 0) {
+ *out_alert = SSL_AD_DECODE_ERROR;
+ return false;
+ }
+
+ // If the client-selected version is less than what we support, then Token
+ // Binding wasn't negotiated (but the extension was parsed successfully).
+ if (version < kTokenBindingMinVersion) {
+ return true;
+ }
+
+ // If the client-selected version is higher than we support, use our max
+ // version. Otherwise, use the client's version.
+ hs->negotiated_token_binding_version =
+ std::min(version, kTokenBindingMaxVersion);
+ if (!select_tb_param(ssl, params)) {
+ return true;
+ }
+
+ ssl->token_binding_negotiated = true;
+ return true;
+}
+
+static bool ext_token_binding_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) {
+ SSL *const ssl = hs->ssl;
+
+ if (!ssl->token_binding_negotiated) {
+ return true;
+ }
+
+ CBB contents, params;
+ if (!CBB_add_u16(out, TLSEXT_TYPE_token_binding) ||
+ !CBB_add_u16_length_prefixed(out, &contents) ||
+ !CBB_add_u16(&contents, hs->negotiated_token_binding_version) ||
+ !CBB_add_u8_length_prefixed(&contents, ¶ms) ||
+ !CBB_add_u8(¶ms, ssl->negotiated_token_binding_param) ||
+ !CBB_flush(out)) {
+ return false;
+ }
+
+ return true;
+}
+
+// QUIC Transport Parameters
+
+static bool ext_quic_transport_params_add_clienthello(SSL_HANDSHAKE *hs,
+ CBB *out) {
+ SSL *const ssl = hs->ssl;
+ if (!ssl->quic_transport_params || hs->max_version <= TLS1_2_VERSION) {
+ return true;
+ }
+
+ CBB contents;
+ if (!CBB_add_u16(out, TLSEXT_TYPE_quic_transport_parameters) ||
+ !CBB_add_u16_length_prefixed(out, &contents) ||
+ !CBB_add_bytes(&contents, ssl->quic_transport_params,
+ ssl->quic_transport_params_len) ||
+ !CBB_flush(out)) {
+ return false;
+ }
+ return true;
+}
+
+static bool ext_quic_transport_params_parse_serverhello(SSL_HANDSHAKE *hs,
+ uint8_t *out_alert,
+ CBS *contents) {
+ SSL *const ssl = hs->ssl;
+ if (contents == nullptr) {
+ return true;
+ }
+ // QUIC requires TLS 1.3.
+ if (ssl_protocol_version(ssl) < TLS1_3_VERSION) {
+ *out_alert = SSL_AD_UNSUPPORTED_EXTENSION;
+ return false;
+ }
+
+ return ssl->s3->peer_quic_transport_params.CopyFrom(*contents);
+}
+
+static bool ext_quic_transport_params_parse_clienthello(SSL_HANDSHAKE *hs,
+ uint8_t *out_alert,
+ CBS *contents) {
+ SSL *const ssl = hs->ssl;
+ if (!contents || !ssl->quic_transport_params) {
+ return true;
+ }
+ // Ignore the extension before TLS 1.3.
+ if (ssl_protocol_version(ssl) < TLS1_3_VERSION) {
+ return true;
+ }
+
+ return ssl->s3->peer_quic_transport_params.CopyFrom(*contents);
+}
+
+static bool ext_quic_transport_params_add_serverhello(SSL_HANDSHAKE *hs,
+ CBB *out) {
+ SSL *const ssl = hs->ssl;
+ if (!ssl->quic_transport_params) {
+ return true;
+ }
+
+ CBB contents;
+ if (!CBB_add_u16(out, TLSEXT_TYPE_quic_transport_parameters) ||
+ !CBB_add_u16_length_prefixed(out, &contents) ||
+ !CBB_add_bytes(&contents, ssl->quic_transport_params,
+ ssl->quic_transport_params_len) ||
+ !CBB_flush(out)) {
+ return false;
+ }
+
+ return true;
+}
+
+
+// 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,
+ NULL,
+ 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,
+ NULL,
+ 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_psk_key_exchange_modes,
+ NULL,
+ ext_psk_key_exchange_modes_add_clienthello,
+ forbid_parse_serverhello,
+ ext_psk_key_exchange_modes_parse_clienthello,
+ dont_add_serverhello,
+ },
+ {
+ TLSEXT_TYPE_early_data,
+ NULL,
+ ext_early_data_add_clienthello,
+ ext_early_data_parse_serverhello,
+ ext_early_data_parse_clienthello,
+ ext_early_data_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,
+ },
+ {
+ TLSEXT_TYPE_dummy_pq_padding,
+ NULL,
+ ext_dummy_pq_padding_add_clienthello,
+ ext_dummy_pq_padding_parse_serverhello,
+ ext_dummy_pq_padding_parse_clienthello,
+ ext_dummy_pq_padding_add_serverhello,
+ },
+ {
+ TLSEXT_TYPE_quic_transport_parameters,
+ NULL,
+ ext_quic_transport_params_add_clienthello,
+ ext_quic_transport_params_parse_serverhello,
+ ext_quic_transport_params_parse_clienthello,
+ ext_quic_transport_params_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,
+ dont_add_serverhello,
+ },
+ {
+ TLSEXT_TYPE_token_binding,
+ NULL,
+ ext_token_binding_add_clienthello,
+ ext_token_binding_parse_serverhello,
+ ext_token_binding_parse_clienthello,
+ ext_token_binding_add_serverhello,
+ },
+};
+
+#define kNumExtensions (sizeof(kExtensions) / sizeof(struct tls_extension))
+
+static_assert(kNumExtensions <=
+ sizeof(((SSL_HANDSHAKE *)NULL)->extensions.sent) * 8,
+ "too many extensions for sent bitset");
+static_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_add_clienthello_tlsext(SSL_HANDSHAKE *hs, CBB *out, size_t header_len) {
+ SSL *const ssl = hs->ssl;
+ // Don't add extensions for SSLv3 unless doing secure renegotiation.
+ if (hs->client_version == SSL3_VERSION &&
+ !ssl->s3->send_connection_binding) {
+ return 1;
+ }
+
+ CBB extensions;
+ if (!CBB_add_u16_length_prefixed(out, &extensions)) {
+ OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
+ return 0;
+ }
+
+ hs->extensions.sent = 0;
+ hs->custom_extensions.sent = 0;
+
+ for (size_t i = 0; i < kNumExtensions; i++) {
+ if (kExtensions[i].init != NULL) {
+ kExtensions[i].init(hs);
+ }
+ }
+
+ 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(hs, ssl_grease_extension1);
+ if (!CBB_add_u16(&extensions, grease_ext1) ||
+ !CBB_add_u16(&extensions, 0 /* zero length */)) {
+ OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
+ return 0;
+ }
+ }
+
+ for (size_t i = 0; i < kNumExtensions; i++) {
+ const size_t len_before = CBB_len(&extensions);
+ if (!kExtensions[i].add_clienthello(hs, &extensions)) {
+ OPENSSL_PUT_ERROR(SSL, SSL_R_ERROR_ADDING_EXTENSION);
+ ERR_add_error_dataf("extension %u", (unsigned)kExtensions[i].value);
+ return 0;
+ }
+
+ if (CBB_len(&extensions) != len_before) {
+ hs->extensions.sent |= (1u << i);
+ }
+ }
+
+ if (!custom_ext_add_clienthello(hs, &extensions)) {
+ OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
+ return 0;
+ }
+
+ 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(hs, 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 */)) {
+ OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
+ return 0;
+ }
+ }
+
+ if (!SSL_is_dtls(ssl)) {
+ size_t psk_extension_len = ext_pre_shared_key_clienthello_length(hs);
+ header_len += 2 + CBB_len(&extensions) + psk_extension_len;
+ 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)) {
+ OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
+ return 0;
+ }
+
+ OPENSSL_memset(padding_bytes, 0, padding_len);
+ }
+ }
+
+ // The PSK extension must be last, including after the padding.
+ if (!ext_pre_shared_key_add_clienthello(hs, &extensions)) {
+ OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
+ return 0;
+ }
+
+ // Discard empty extensions blocks.
+ if (CBB_len(&extensions) == 0) {
+ CBB_discard_child(out);
+ }
+
+ return CBB_flush(out);
+}
+
+int ssl_add_serverhello_tlsext(SSL_HANDSHAKE *hs, CBB *out) {
+ SSL *const ssl = hs->ssl;
+ CBB extensions;
+ if (!CBB_add_u16_length_prefixed(out, &extensions)) {
+ goto err;
+ }
+
+ for (unsigned i = 0; i < kNumExtensions; i++) {
+ if (!(hs->extensions.received & (1u << i))) {
+ // Don't send extensions that were not received.
+ continue;
+ }
+
+ if (!kExtensions[i].add_serverhello(hs, &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(hs, &extensions)) {
+ goto err;
+ }
+
+ // Discard empty extensions blocks before TLS 1.3.
+ if (ssl_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_HANDSHAKE *hs,
+ const SSL_CLIENT_HELLO *client_hello,
+ int *out_alert) {
+ SSL *const ssl = hs->ssl;
+ for (size_t i = 0; i < kNumExtensions; i++) {
+ if (kExtensions[i].init != NULL) {
+ kExtensions[i].init(hs);
+ }
+ }
+
+ hs->extensions.received = 0;
+ 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(hs, out_alert, type, &extension)) {
+ OPENSSL_PUT_ERROR(SSL, SSL_R_ERROR_PARSING_EXTENSION);
+ return 0;
+ }
+ continue;
+ }
+
+ hs->extensions.received |= (1u << ext_index);
+ uint8_t alert = SSL_AD_DECODE_ERROR;
+ if (!ext->parse_clienthello(hs, &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 (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;
+ 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(hs, &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_HANDSHAKE *hs,
+ const SSL_CLIENT_HELLO *client_hello) {
+ SSL *const ssl = hs->ssl;
+ int alert = SSL_AD_DECODE_ERROR;
+ if (ssl_scan_clienthello_tlsext(hs, client_hello, &alert) <= 0) {
+ ssl_send_alert(ssl, SSL3_AL_FATAL, alert);
+ return 0;
+ }
+
+ if (ssl_check_clienthello_tlsext(hs) <= 0) {
+ OPENSSL_PUT_ERROR(SSL, SSL_R_CLIENTHELLO_TLSEXT);
+ return 0;
+ }
+
+ return 1;
+}
+
+static int ssl_scan_serverhello_tlsext(SSL_HANDSHAKE *hs, CBS *cbs,
+ int *out_alert) {
+ SSL *const ssl = hs->ssl;
+ // Before TLS 1.3, ServerHello extensions blocks may be omitted if empty.
+ if (CBS_len(cbs) == 0 && ssl_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) {
+ hs->received_custom_extension = true;
+ if (!custom_ext_parse_serverhello(hs, out_alert, type, &extension)) {
+ return 0;
+ }
+ continue;
+ }
+
+ static_assert(kNumExtensions <= sizeof(hs->extensions.sent) * 8,
+ "too many bits");
+
+ if (!(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(hs, &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(hs, &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_HANDSHAKE *hs) {
+ SSL *const ssl = hs->ssl;
+
+ if (ssl->token_binding_negotiated &&
+ !(SSL_get_secure_renegotiation_support(ssl) &&
+ SSL_get_extms_support(ssl))) {
+ OPENSSL_PUT_ERROR(SSL, SSL_R_NEGOTIATED_TB_WITHOUT_EMS_OR_RI);
+ ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNSUPPORTED_EXTENSION);
+ return -1;
+ }
+
+ 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->session_ctx->tlsext_servername_callback != 0) {
+ ret = ssl->session_ctx->tlsext_servername_callback(
+ ssl, &al, ssl->session_ctx->tlsext_servername_arg);
+ }
+
+ switch (ret) {
+ case SSL_TLSEXT_ERR_ALERT_FATAL:
+ ssl_send_alert(ssl, SSL3_AL_FATAL, al);
+ return -1;
+
+ case SSL_TLSEXT_ERR_NOACK:
+ hs->should_ack_sni = false;
+ return 1;
+
+ default:
+ return 1;
+ }
+}
+
+int ssl_parse_serverhello_tlsext(SSL_HANDSHAKE *hs, CBS *cbs) {
+ SSL *const ssl = hs->ssl;
+ int alert = SSL_AD_DECODE_ERROR;
+ if (ssl_scan_serverhello_tlsext(hs, cbs, &alert) <= 0) {
+ ssl_send_alert(ssl, SSL3_AL_FATAL, alert);
+ return 0;
+ }
+
+ return 1;
+}
+
+static enum ssl_ticket_aead_result_t decrypt_ticket_with_cipher_ctx(
+ uint8_t **out, size_t *out_len, EVP_CIPHER_CTX *cipher_ctx,
+ HMAC_CTX *hmac_ctx, const uint8_t *ticket, size_t ticket_len) {
+ 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.
+ return ssl_ticket_aead_ignore_ticket;
+ }
+ 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) {
+ return ssl_ticket_aead_ignore_ticket;
+ }
+
+ // 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;
+ UniquePtr<uint8_t> plaintext((uint8_t *)OPENSSL_malloc(ciphertext_len));
+ if (!plaintext) {
+ return ssl_ticket_aead_error;
+ }
+ size_t plaintext_len;
+#if defined(BORINGSSL_UNSAFE_FUZZER_MODE)
+ OPENSSL_memcpy(plaintext.get(), ciphertext, ciphertext_len);
+ plaintext_len = ciphertext_len;
+#else
+ if (ciphertext_len >= INT_MAX) {
+ return ssl_ticket_aead_ignore_ticket;
+ }
+ int len1, len2;
+ if (!EVP_DecryptUpdate(cipher_ctx, plaintext.get(), &len1, ciphertext,
+ (int)ciphertext_len) ||
+ !EVP_DecryptFinal_ex(cipher_ctx, plaintext.get() + len1, &len2)) {
+ ERR_clear_error();
+ return ssl_ticket_aead_ignore_ticket;
+ }
+ plaintext_len = (size_t)(len1) + len2;
+#endif
+
+ *out = plaintext.release();
+ *out_len = plaintext_len;
+ return ssl_ticket_aead_success;
+}
+
+static enum ssl_ticket_aead_result_t ssl_decrypt_ticket_with_cb(
+ SSL *ssl, uint8_t **out, size_t *out_len, bool *out_renew_ticket,
+ const uint8_t *ticket, size_t ticket_len) {
+ assert(ticket_len >= SSL_TICKET_KEY_NAME_LEN + EVP_MAX_IV_LENGTH);
+ ScopedEVP_CIPHER_CTX cipher_ctx;
+ ScopedHMAC_CTX hmac_ctx;
+ const uint8_t *iv = ticket + SSL_TICKET_KEY_NAME_LEN;
+ int cb_ret = ssl->session_ctx->tlsext_ticket_key_cb(
+ ssl, (uint8_t *)ticket /* name */, (uint8_t *)iv, cipher_ctx.get(),
+ hmac_ctx.get(), 0 /* decrypt */);
+ if (cb_ret < 0) {
+ return ssl_ticket_aead_error;
+ } else if (cb_ret == 0) {
+ return ssl_ticket_aead_ignore_ticket;
+ } else if (cb_ret == 2) {
+ *out_renew_ticket = true;
+ } else {
+ assert(cb_ret == 1);
+ }
+ return decrypt_ticket_with_cipher_ctx(out, out_len, cipher_ctx.get(),
+ hmac_ctx.get(), ticket, ticket_len);
+}
+
+static enum ssl_ticket_aead_result_t ssl_decrypt_ticket_with_ticket_keys(
+ SSL *ssl, uint8_t **out, size_t *out_len, const uint8_t *ticket,
+ size_t ticket_len) {
+ assert(ticket_len >= SSL_TICKET_KEY_NAME_LEN + EVP_MAX_IV_LENGTH);
+ SSL_CTX *ctx = ssl->session_ctx;
+
+ // Rotate the ticket key if necessary.
+ if (!ssl_ctx_rotate_ticket_encryption_key(ctx)) {
+ return ssl_ticket_aead_error;
+ }
+
+ // Pick the matching ticket key and decrypt.
+ ScopedEVP_CIPHER_CTX cipher_ctx;
+ ScopedHMAC_CTX hmac_ctx;
+ {
+ MutexReadLock lock(&ctx->lock);
+ const tlsext_ticket_key *key;
+ if (ctx->tlsext_ticket_key_current &&
+ !OPENSSL_memcmp(ctx->tlsext_ticket_key_current->name, ticket,
+ SSL_TICKET_KEY_NAME_LEN)) {
+ key = ctx->tlsext_ticket_key_current;
+ } else if (ctx->tlsext_ticket_key_prev &&
+ !OPENSSL_memcmp(ctx->tlsext_ticket_key_prev->name, ticket,
+ SSL_TICKET_KEY_NAME_LEN)) {
+ key = ctx->tlsext_ticket_key_prev;
+ } else {
+ return ssl_ticket_aead_ignore_ticket;
+ }
+ const uint8_t *iv = ticket + SSL_TICKET_KEY_NAME_LEN;
+ if (!HMAC_Init_ex(hmac_ctx.get(), key->hmac_key, sizeof(key->hmac_key),
+ tlsext_tick_md(), NULL) ||
+ !EVP_DecryptInit_ex(cipher_ctx.get(), EVP_aes_128_cbc(), NULL,
+ key->aes_key, iv)) {
+ return ssl_ticket_aead_error;
+ }
+ }
+ return decrypt_ticket_with_cipher_ctx(out, out_len, cipher_ctx.get(),
+ hmac_ctx.get(), ticket, ticket_len);
+}
+
+static enum ssl_ticket_aead_result_t ssl_decrypt_ticket_with_method(
+ SSL *ssl, uint8_t **out, size_t *out_len, bool *out_renew_ticket,
+ const uint8_t *ticket, size_t ticket_len) {
+ uint8_t *plaintext = (uint8_t *)OPENSSL_malloc(ticket_len);
+ if (plaintext == NULL) {
+ OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
+ return ssl_ticket_aead_error;
+ }
+
+ size_t plaintext_len;
+ const enum ssl_ticket_aead_result_t result =
+ ssl->session_ctx->ticket_aead_method->open(
+ ssl, plaintext, &plaintext_len, ticket_len, ticket, ticket_len);
+
+ if (result == ssl_ticket_aead_success) {
+ *out = plaintext;
+ plaintext = NULL;
+ *out_len = plaintext_len;
+ }
+
+ OPENSSL_free(plaintext);
+ return result;
+}
+
+enum ssl_ticket_aead_result_t ssl_process_ticket(
+ SSL *ssl, UniquePtr<SSL_SESSION> *out_session, bool *out_renew_ticket,
+ const uint8_t *ticket, size_t ticket_len, const uint8_t *session_id,
+ size_t session_id_len) {
+ *out_renew_ticket = false;
+ out_session->reset();
+
+ if ((SSL_get_options(ssl) & SSL_OP_NO_TICKET) ||
+ session_id_len > SSL_MAX_SSL_SESSION_ID_LENGTH) {
+ return ssl_ticket_aead_ignore_ticket;
+ }
+
+ uint8_t *plaintext = NULL;
+ size_t plaintext_len;
+ enum ssl_ticket_aead_result_t result;
+ if (ssl->session_ctx->ticket_aead_method != NULL) {
+ result = ssl_decrypt_ticket_with_method(
+ ssl, &plaintext, &plaintext_len, out_renew_ticket, ticket, ticket_len);
+ } else {
+ // 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) {
+ return ssl_ticket_aead_ignore_ticket;
+ }
+ if (ssl->session_ctx->tlsext_ticket_key_cb != NULL) {
+ result = ssl_decrypt_ticket_with_cb(ssl, &plaintext, &plaintext_len,
+ out_renew_ticket, ticket, ticket_len);
+ } else {
+ result = ssl_decrypt_ticket_with_ticket_keys(
+ ssl, &plaintext, &plaintext_len, ticket, ticket_len);
+ }
+ }
+
+ if (result != ssl_ticket_aead_success) {
+ return result;
+ }
+
+ // Decode the session.
+ UniquePtr<SSL_SESSION> session(
+ SSL_SESSION_from_bytes(plaintext, plaintext_len, ssl->ctx));
+ OPENSSL_free(plaintext);
+
+ if (!session) {
+ ERR_clear_error(); // Don't leave an error on the queue.
+ return ssl_ticket_aead_ignore_ticket;
+ }
+
+ // Copy the client's session ID into the new session, to denote the ticket has
+ // been accepted.
+ OPENSSL_memcpy(session->session_id, session_id, session_id_len);
+ session->session_id_length = session_id_len;
+
+ *out_session = std::move(session);
+ return ssl_ticket_aead_success;
+}
+
+bool tls1_parse_peer_sigalgs(SSL_HANDSHAKE *hs, const CBS *in_sigalgs) {
+ // Extension ignored for inappropriate versions
+ if (ssl_protocol_version(hs->ssl) < TLS1_2_VERSION) {
+ return true;
+ }
+
+ return parse_u16_array(in_sigalgs, &hs->peer_sigalgs);
+}
+
+bool tls1_get_legacy_signature_algorithm(uint16_t *out, const EVP_PKEY *pkey) {
+ switch (EVP_PKEY_id(pkey)) {
+ case EVP_PKEY_RSA:
+ *out = SSL_SIGN_RSA_PKCS1_MD5_SHA1;
+ return true;
+ case EVP_PKEY_EC:
+ *out = SSL_SIGN_ECDSA_SHA1;
+ return true;
+ default:
+ return false;
+ }
+}
+
+bool tls1_choose_signature_algorithm(SSL_HANDSHAKE *hs, uint16_t *out) {
+ SSL *const ssl = hs->ssl;
+ CERT *cert = ssl->cert;
+
+ // Before TLS 1.2, the signature algorithm isn't negotiated as part of the
+ // handshake.
+ if (ssl_protocol_version(ssl) < TLS1_2_VERSION) {
+ if (!tls1_get_legacy_signature_algorithm(out, hs->local_pubkey.get())) {
+ OPENSSL_PUT_ERROR(SSL, SSL_R_NO_COMMON_SIGNATURE_ALGORITHMS);
+ return false;
+ }
+ return true;
+ }
+
+ Span<const uint16_t> sigalgs = kSignSignatureAlgorithms;
+ if (cert->sigalgs != nullptr) {
+ sigalgs = MakeConstSpan(cert->sigalgs, cert->num_sigalgs);
+ }
+
+ Span<const uint16_t> peer_sigalgs = hs->peer_sigalgs;
+ if (peer_sigalgs.empty() && ssl_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;
+ }
+
+ for (uint16_t sigalg : sigalgs) {
+ // 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(hs, sigalg)) {
+ continue;
+ }
+
+ for (uint16_t peer_sigalg : peer_sigalgs) {
+ if (sigalg == peer_sigalg) {
+ *out = sigalg;
+ return true;
+ }
+ }
+ }
+
+ OPENSSL_PUT_ERROR(SSL, SSL_R_NO_COMMON_SIGNATURE_ALGORITHMS);
+ return false;
+}
+
+int tls1_verify_channel_id(SSL_HANDSHAKE *hs, const SSLMessage &msg) {
+ SSL *const ssl = hs->ssl;
+ // A Channel ID handshake message is structured to contain multiple
+ // extensions, but the only one that can be present is Channel ID.
+ uint16_t extension_type;
+ CBS channel_id = msg.body, extension;
+ 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);
+ ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
+ return 0;
+ }
+
+ UniquePtr<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;
+ }
+
+ UniquePtr<ECDSA_SIG> sig(ECDSA_SIG_new());
+ UniquePtr<BIGNUM> x(BN_new()), y(BN_new());
+ if (!sig || !x || !y) {
+ return 0;
+ }
+
+ const uint8_t *p = CBS_data(&extension);
+ if (BN_bin2bn(p + 0, 32, x.get()) == NULL ||
+ BN_bin2bn(p + 32, 32, y.get()) == NULL ||
+ BN_bin2bn(p + 64, 32, sig->r) == NULL ||
+ BN_bin2bn(p + 96, 32, sig->s) == NULL) {
+ return 0;
+ }
+
+ UniquePtr<EC_KEY> key(EC_KEY_new());
+ UniquePtr<EC_POINT> point(EC_POINT_new(p256.get()));
+ if (!key || !point ||
+ !EC_POINT_set_affine_coordinates_GFp(p256.get(), point.get(), x.get(),
+ y.get(), nullptr) ||
+ !EC_KEY_set_group(key.get(), p256.get()) ||
+ !EC_KEY_set_public_key(key.get(), point.get())) {
+ return 0;
+ }
+
+ uint8_t digest[EVP_MAX_MD_SIZE];
+ size_t digest_len;
+ if (!tls1_channel_id_hash(hs, digest, &digest_len)) {
+ return 0;
+ }
+
+ int sig_ok = ECDSA_do_verify(digest, digest_len, sig.get(), key.get());
+#if defined(BORINGSSL_UNSAFE_FUZZER_MODE)
+ sig_ok = 1;
+ ERR_clear_error();
+#endif
+ if (!sig_ok) {
+ OPENSSL_PUT_ERROR(SSL, SSL_R_CHANNEL_ID_SIGNATURE_INVALID);
+ ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECRYPT_ERROR);
+ ssl->s3->tlsext_channel_id_valid = false;
+ return 0;
+ }
+
+ OPENSSL_memcpy(ssl->s3->tlsext_channel_id, p, 64);
+ return 1;
+}
+
+bool tls1_write_channel_id(SSL_HANDSHAKE *hs, CBB *cbb) {
+ SSL *const ssl = hs->ssl;
+ uint8_t digest[EVP_MAX_MD_SIZE];
+ size_t digest_len;
+ if (!tls1_channel_id_hash(hs, digest, &digest_len)) {
+ return false;
+ }
+
+ EC_KEY *ec_key = EVP_PKEY_get0_EC_KEY(ssl->tlsext_channel_id_private);
+ if (ec_key == nullptr) {
+ OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
+ return false;
+ }
+
+ UniquePtr<BIGNUM> x(BN_new()), y(BN_new());
+ if (!x || !y ||
+ !EC_POINT_get_affine_coordinates_GFp(EC_KEY_get0_group(ec_key),
+ EC_KEY_get0_public_key(ec_key),
+ x.get(), y.get(), nullptr)) {
+ return false;
+ }
+
+ UniquePtr<ECDSA_SIG> sig(ECDSA_do_sign(digest, digest_len, ec_key));
+ if (!sig) {
+ return false;
+ }
+
+ CBB child;
+ if (!CBB_add_u16(cbb, TLSEXT_TYPE_channel_id) ||
+ !CBB_add_u16_length_prefixed(cbb, &child) ||
+ !BN_bn2cbb_padded(&child, 32, x.get()) ||
+ !BN_bn2cbb_padded(&child, 32, y.get()) ||
+ !BN_bn2cbb_padded(&child, 32, sig->r) ||
+ !BN_bn2cbb_padded(&child, 32, sig->s) ||
+ !CBB_flush(cbb)) {
+ return false;
+ }
+
+ return true;
+}
+
+int tls1_channel_id_hash(SSL_HANDSHAKE *hs, uint8_t *out, size_t *out_len) {
+ SSL *const ssl = hs->ssl;
+ if (ssl_protocol_version(ssl) >= TLS1_3_VERSION) {
+ Array<uint8_t> msg;
+ if (!tls13_get_cert_verify_signature_input(hs, &msg,
+ ssl_cert_verify_channel_id)) {
+ return 0;
+ }
+ SHA256(msg.data(), msg.size(), out);
+ *out_len = SHA256_DIGEST_LENGTH;
+ 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 hs_hash[EVP_MAX_MD_SIZE];
+ size_t hs_hash_len;
+ if (!hs->transcript.GetHash(hs_hash, &hs_hash_len)) {
+ return 0;
+ }
+ SHA256_Update(&ctx, hs_hash, (size_t)hs_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 |hs->new_session| so that Channel ID resumptions can sign that
+// data.
+int tls1_record_handshake_hashes_for_channel_id(SSL_HANDSHAKE *hs) {
+ SSL *const ssl = hs->ssl;
+ // 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 0;
+ }
+
+ static_assert(
+ sizeof(hs->new_session->original_handshake_hash) == EVP_MAX_MD_SIZE,
+ "original_handshake_hash is too small");
+
+ size_t digest_len;
+ if (!hs->transcript.GetHash(hs->new_session->original_handshake_hash,
+ &digest_len)) {
+ return 0;
+ }
+
+ static_assert(EVP_MAX_MD_SIZE <= 0xff,
+ "EVP_MAX_MD_SIZE does not fit in uint8_t");
+ hs->new_session->original_handshake_hash_len = (uint8_t)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;
+}
+
+int ssl_is_sct_list_valid(const CBS *contents) {
+ // Shallow parse the SCT list for sanity. By the RFC
+ // (https://tools.ietf.org/html/rfc6962#section-3.3) neither the list nor any
+ // of the SCTs may be empty.
+ CBS copy = *contents;
+ CBS sct_list;
+ if (!CBS_get_u16_length_prefixed(©, &sct_list) ||
+ CBS_len(©) != 0 ||
+ CBS_len(&sct_list) == 0) {
+ return 0;
+ }
+
+ while (CBS_len(&sct_list) > 0) {
+ CBS sct;
+ if (!CBS_get_u16_length_prefixed(&sct_list, &sct) ||
+ CBS_len(&sct) == 0) {
+ return 0;
+ }
+ }
+
+ return 1;
+}
+
+} // namespace bssl
+
+using namespace bssl;
+
+int SSL_early_callback_ctx_extension_get(const SSL_CLIENT_HELLO *client_hello,
+ uint16_t extension_type,
+ const uint8_t **out_data,
+ size_t *out_len) {
+ CBS cbs;
+ if (!ssl_client_hello_get_extension(client_hello, &cbs, extension_type)) {
+ return 0;
+ }
+
+ *out_data = CBS_data(&cbs);
+ *out_len = CBS_len(&cbs);
+ return 1;
+}
+
+void SSL_CTX_set_ed25519_enabled(SSL_CTX *ctx, int enabled) {
+ ctx->ed25519_enabled = !!enabled;
+}
+
+int SSL_extension_supported(unsigned extension_value) {
+ uint32_t index;
+ return extension_value == TLSEXT_TYPE_padding ||
+ tls_extension_find(&index, extension_value) != NULL;
+}
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