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/* 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 <openssl/bytestring.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 <openssl/type_check.h>
#include "internal.h"
#include "../crypto/internal.h"
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) {
CBS extensions = *cbs;
size_t num_extensions = 0, i = 0;
uint16_t *extension_types = NULL;
int ret = 0;
/* First pass: count the extensions. */
while (CBS_len(&extensions) > 0) {
uint16_t type;
CBS extension;
if (!CBS_get_u16(&extensions, &type) ||
!CBS_get_u16_length_prefixed(&extensions, &extension)) {
goto done;
}
num_extensions++;
}
if (num_extensions == 0) {
return 1;
}
extension_types = OPENSSL_malloc(sizeof(uint16_t) * num_extensions);
if (extension_types == NULL) {
OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
goto done;
}
/* Second pass: gather the extension types. */
extensions = *cbs;
for (i = 0; i < num_extensions; i++) {
CBS extension;
if (!CBS_get_u16(&extensions, &extension_types[i]) ||
!CBS_get_u16_length_prefixed(&extensions, &extension)) {
/* This should not happen. */
goto done;
}
}
assert(CBS_len(&extensions) == 0);
/* Sort the extensions and make sure there are no duplicates. */
qsort(extension_types, num_extensions, sizeof(uint16_t), compare_uint16_t);
for (i = 1; i < num_extensions; i++) {
if (extension_types[i - 1] == extension_types[i]) {
goto done;
}
}
ret = 1;
done:
OPENSSL_free(extension_types);
return ret;
}
int ssl_client_hello_init(SSL *ssl, SSL_CLIENT_HELLO *out, const uint8_t *in,
size_t in_len) {
OPENSSL_memset(out, 0, sizeof(*out));
out->ssl = ssl;
out->client_hello = in;
out->client_hello_len = in_len;
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;
}
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;
}
static const uint16_t kDefaultGroups[] = {
SSL_CURVE_X25519,
SSL_CURVE_SECP256R1,
SSL_CURVE_SECP384R1,
};
void tls1_get_grouplist(SSL *ssl, const uint16_t **out_group_ids,
size_t *out_group_ids_len) {
*out_group_ids = ssl->supported_group_list;
*out_group_ids_len = ssl->supported_group_list_len;
if (!*out_group_ids) {
*out_group_ids = kDefaultGroups;
*out_group_ids_len = OPENSSL_ARRAY_SIZE(kDefaultGroups);
}
}
int tls1_get_shared_group(SSL_HANDSHAKE *hs, uint16_t *out_group_id) {
SSL *const ssl = hs->ssl;
assert(ssl->server);
const uint16_t *groups, *pref, *supp;
size_t groups_len, pref_len, supp_len;
tls1_get_grouplist(ssl, &groups, &groups_len);
/* Clients are not required to send a supported_groups extension. In this
* case, the server is free to pick any group it likes. See RFC 4492,
* section 4, paragraph 3.
*
* However, in the interests of compatibility, we will skip ECDH if the
* client didn't send an extension because we can't be sure that they'll
* support our favoured group. Thus we do not special-case an emtpy
* |peer_supported_group_list|. */
if (ssl->options & SSL_OP_CIPHER_SERVER_PREFERENCE) {
pref = groups;
pref_len = groups_len;
supp = hs->peer_supported_group_list;
supp_len = hs->peer_supported_group_list_len;
} else {
pref = hs->peer_supported_group_list;
pref_len = hs->peer_supported_group_list_len;
supp = groups;
supp_len = groups_len;
}
for (size_t i = 0; i < pref_len; i++) {
for (size_t j = 0; j < supp_len; j++) {
if (pref[i] == supp[j]) {
*out_group_id = pref[i];
return 1;
}
}
}
return 0;
}
int tls1_set_curves(uint16_t **out_group_ids, size_t *out_group_ids_len,
const int *curves, size_t ncurves) {
uint16_t *group_ids;
group_ids = OPENSSL_malloc(ncurves * sizeof(uint16_t));
if (group_ids == NULL) {
return 0;
}
for (size_t i = 0; i < ncurves; i++) {
if (!ssl_nid_to_group_id(&group_ids[i], curves[i])) {
OPENSSL_free(group_ids);
return 0;
}
}
OPENSSL_free(*out_group_ids);
*out_group_ids = group_ids;
*out_group_ids_len = ncurves;
return 1;
}
int tls1_set_curves_list(uint16_t **out_group_ids, size_t *out_group_ids_len,
const char *curves) {
uint16_t *group_ids = NULL;
size_t ncurves = 0;
const char *col;
const char *ptr = curves;
do {
col = strchr(ptr, ':');
uint16_t group_id;
if (!ssl_name_to_group_id(&group_id, ptr,
col ? (size_t)(col - ptr) : strlen(ptr))) {
goto err;
}
uint16_t *new_group_ids = OPENSSL_realloc(group_ids,
(ncurves + 1) * sizeof(uint16_t));
if (new_group_ids == NULL) {
goto err;
}
group_ids = new_group_ids;
group_ids[ncurves] = group_id;
ncurves++;
if (col) {
ptr = col + 1;
}
} while (col);
OPENSSL_free(*out_group_ids);
*out_group_ids = group_ids;
*out_group_ids_len = ncurves;
return 1;
err:
OPENSSL_free(group_ids);
return 0;
}
int tls1_check_group_id(SSL *ssl, uint16_t group_id) {
const uint16_t *groups;
size_t groups_len;
tls1_get_grouplist(ssl, &groups, &groups_len);
for (size_t i = 0; i < groups_len; i++) {
if (groups[i] == group_id) {
return 1;
}
}
return 0;
}
/* kVerifySignatureAlgorithms is the default list of accepted signature
* algorithms for verifying.
*
* For now, RSA-PSS signature algorithms are not enabled on Android's system
* BoringSSL. Once the change in Chrome has stuck and the values are finalized,
* restore them. */
static const uint16_t kVerifySignatureAlgorithms[] = {
/* List our preferred algorithms first. */
SSL_SIGN_ED25519,
SSL_SIGN_ECDSA_SECP256R1_SHA256,
#if !defined(BORINGSSL_ANDROID_SYSTEM)
SSL_SIGN_RSA_PSS_SHA256,
#endif
SSL_SIGN_RSA_PKCS1_SHA256,
/* Larger hashes are acceptable. */
SSL_SIGN_ECDSA_SECP384R1_SHA384,
#if !defined(BORINGSSL_ANDROID_SYSTEM)
SSL_SIGN_RSA_PSS_SHA384,
#endif
SSL_SIGN_RSA_PKCS1_SHA384,
/* TODO(davidben): Remove this. */
#if defined(BORINGSSL_ANDROID_SYSTEM)
SSL_SIGN_ECDSA_SECP521R1_SHA512,
#endif
#if !defined(BORINGSSL_ANDROID_SYSTEM)
SSL_SIGN_RSA_PSS_SHA512,
#endif
SSL_SIGN_RSA_PKCS1_SHA512,
/* For now, SHA-1 is still accepted but least preferable. */
SSL_SIGN_RSA_PKCS1_SHA1,
};
/* kSignSignatureAlgorithms is the default list of supported signature
* algorithms for signing.
*
* For now, RSA-PSS signature algorithms are not enabled on Android's system
* BoringSSL. Once the change in Chrome has stuck and the values are finalized,
* restore them. */
static const uint16_t kSignSignatureAlgorithms[] = {
/* List our preferred algorithms first. */
SSL_SIGN_ED25519,
SSL_SIGN_ECDSA_SECP256R1_SHA256,
#if !defined(BORINGSSL_ANDROID_SYSTEM)
SSL_SIGN_RSA_PSS_SHA256,
#endif
SSL_SIGN_RSA_PKCS1_SHA256,
/* If needed, sign larger hashes.
*
* TODO(davidben): Determine which of these may be pruned. */
SSL_SIGN_ECDSA_SECP384R1_SHA384,
#if !defined(BORINGSSL_ANDROID_SYSTEM)
SSL_SIGN_RSA_PSS_SHA384,
#endif
SSL_SIGN_RSA_PKCS1_SHA384,
SSL_SIGN_ECDSA_SECP521R1_SHA512,
#if !defined(BORINGSSL_ANDROID_SYSTEM)
SSL_SIGN_RSA_PSS_SHA512,
#endif
SSL_SIGN_RSA_PKCS1_SHA512,
/* If the peer supports nothing else, sign with SHA-1. */
SSL_SIGN_ECDSA_SHA1,
SSL_SIGN_RSA_PKCS1_SHA1,
};
void SSL_CTX_set_ed25519_enabled(SSL_CTX *ctx, int enabled) {
ctx->ed25519_enabled = !!enabled;
}
int tls12_add_verify_sigalgs(const SSL *ssl, CBB *out) {
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 (!CBB_add_u16(out, sigalgs[i])) {
return 0;
}
}
return 1;
}
int tls12_check_peer_sigalg(SSL *ssl, int *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 1;
}
}
OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_SIGNATURE_TYPE);
*out_alert = SSL_AD_ILLEGAL_PARAMETER;
return 0;
}
/* tls_extension represents a TLS extension that is handled internally. The
* |init| function is called for each handshake, before any other functions of
* the extension. Then the add and parse callbacks are called as needed.
*
* The parse callbacks receive a |CBS| that contains the contents of the
* extension (i.e. not including the type and length bytes). If an extension is
* not received then the parse callbacks will be called with a NULL CBS so that
* they can do any processing needed to handle the absence of an extension.
*
* The add callbacks receive a |CBB| to which the extension can be appended but
* the function is responsible for appending the type and length bytes too.
*
* All callbacks return one for success and zero for error. If a parse function
* returns zero then a fatal alert with value |*out_alert| will be sent. If
* |*out_alert| isn't set, then a |decode_error| alert will be sent. */
struct tls_extension {
uint16_t value;
void (*init)(SSL_HANDSHAKE *hs);
int (*add_clienthello)(SSL_HANDSHAKE *hs, CBB *out);
int (*parse_serverhello)(SSL_HANDSHAKE *hs, uint8_t *out_alert,
CBS *contents);
int (*parse_clienthello)(SSL_HANDSHAKE *hs, uint8_t *out_alert,
CBS *contents);
int (*add_serverhello)(SSL_HANDSHAKE *hs, CBB *out);
};
static int 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 0;
}
return 1;
}
static int ignore_parse_clienthello(SSL_HANDSHAKE *hs, uint8_t *out_alert,
CBS *contents) {
/* This extension from the client is handled elsewhere. */
return 1;
}
static int dont_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) {
return 1;
}
/* Server name indication (SNI).
*
* https://tools.ietf.org/html/rfc6066#section-3. */
static int ext_sni_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) {
SSL *const ssl = hs->ssl;
if (ssl->tlsext_hostname == NULL) {
return 1;
}
CBB contents, server_name_list, name;
if (!CBB_add_u16(out, TLSEXT_TYPE_server_name) ||
!CBB_add_u16_length_prefixed(out, &contents) ||
!CBB_add_u16_length_prefixed(&contents, &server_name_list) ||
!CBB_add_u8(&server_name_list, TLSEXT_NAMETYPE_host_name) ||
!CBB_add_u16_length_prefixed(&server_name_list, &name) ||
!CBB_add_bytes(&name, (const uint8_t *)ssl->tlsext_hostname,
strlen(ssl->tlsext_hostname)) ||
!CBB_flush(out)) {
return 0;
}
return 1;
}
static int ext_sni_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t *out_alert,
CBS *contents) {
SSL *const ssl = hs->ssl;
if (contents == NULL) {
return 1;
}
if (CBS_len(contents) != 0) {
return 0;
}
assert(ssl->tlsext_hostname != NULL);
if (ssl->session == NULL) {
OPENSSL_free(hs->new_session->tlsext_hostname);
hs->new_session->tlsext_hostname = BUF_strdup(ssl->tlsext_hostname);
if (!hs->new_session->tlsext_hostname) {
*out_alert = SSL_AD_INTERNAL_ERROR;
return 0;
}
}
return 1;
}
static int ext_sni_parse_clienthello(SSL_HANDSHAKE *hs, uint8_t *out_alert,
CBS *contents) {
if (contents == NULL) {
return 1;
}
CBS server_name_list, host_name;
uint8_t name_type;
if (!CBS_get_u16_length_prefixed(contents, &server_name_list) ||
!CBS_get_u8(&server_name_list, &name_type) ||
/* Although the server_name extension was intended to be extensible to
* new name types and multiple names, OpenSSL 1.0.x had a bug which meant
* different name types will cause an error. Further, RFC 4366 originally
* defined syntax inextensibly. RFC 6066 corrected this mistake, but
* adding new name types is no longer feasible.
*
* Act as if the extensibility does not exist to simplify parsing. */
!CBS_get_u16_length_prefixed(&server_name_list, &host_name) ||
CBS_len(&server_name_list) != 0 ||
CBS_len(contents) != 0) {
return 0;
}
if (name_type != TLSEXT_NAMETYPE_host_name ||
CBS_len(&host_name) == 0 ||
CBS_len(&host_name) > TLSEXT_MAXLEN_host_name ||
CBS_contains_zero_byte(&host_name)) {
*out_alert = SSL_AD_UNRECOGNIZED_NAME;
return 0;
}
/* Copy the hostname as a string. */
if (!CBS_strdup(&host_name, &hs->hostname)) {
*out_alert = SSL_AD_INTERNAL_ERROR;
return 0;
}
hs->should_ack_sni = 1;
return 1;
}
static int ext_sni_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) {
if (hs->ssl->s3->session_reused ||
!hs->should_ack_sni) {
return 1;
}
if (!CBB_add_u16(out, TLSEXT_TYPE_server_name) ||
!CBB_add_u16(out, 0 /* length */)) {
return 0;
}
return 1;
}
/* Renegotiation indication.
*
* https://tools.ietf.org/html/rfc5746 */
static int ext_ri_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) {
SSL *const ssl = hs->ssl;
uint16_t min_version, max_version;
if (!ssl_get_version_range(ssl, &min_version, &max_version)) {
return 0;
}
/* Renegotiation indication is not necessary in TLS 1.3. */
if (min_version >= TLS1_3_VERSION) {
return 1;
}
assert(ssl->s3->initial_handshake_complete ==
(ssl->s3->previous_client_finished_len != 0));
CBB contents, prev_finished;
if (!CBB_add_u16(out, TLSEXT_TYPE_renegotiate) ||
!CBB_add_u16_length_prefixed(out, &contents) ||
!CBB_add_u8_length_prefixed(&contents, &prev_finished) ||
!CBB_add_bytes(&prev_finished, ssl->s3->previous_client_finished,
ssl->s3->previous_client_finished_len) ||
!CBB_flush(out)) {
return 0;
}
return 1;
}
static int ext_ri_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t *out_alert,
CBS *contents) {
SSL *const ssl = hs->ssl;
if (contents != NULL && ssl3_protocol_version(ssl) >= TLS1_3_VERSION) {
*out_alert = SSL_AD_ILLEGAL_PARAMETER;
return 0;
}
/* Servers may not switch between omitting the extension and supporting it.
* See RFC 5746, sections 3.5 and 4.2. */
if (ssl->s3->initial_handshake_complete &&
(contents != NULL) != ssl->s3->send_connection_binding) {
*out_alert = SSL_AD_HANDSHAKE_FAILURE;
OPENSSL_PUT_ERROR(SSL, SSL_R_RENEGOTIATION_MISMATCH);
return 0;
}
if (contents == NULL) {
/* Strictly speaking, if we want to avoid an attack we should *always* see
* RI even on initial ServerHello because the client doesn't see any
* renegotiation during an attack. However this would mean we could not
* connect to any server which doesn't support RI.
*
* OpenSSL has |SSL_OP_LEGACY_SERVER_CONNECT| to control this, but in
* practical terms every client sets it so it's just assumed here. */
return 1;
}
const size_t expected_len = ssl->s3->previous_client_finished_len +
ssl->s3->previous_server_finished_len;
/* Check for logic errors */
assert(!expected_len || ssl->s3->previous_client_finished_len);
assert(!expected_len || ssl->s3->previous_server_finished_len);
assert(ssl->s3->initial_handshake_complete ==
(ssl->s3->previous_client_finished_len != 0));
assert(ssl->s3->initial_handshake_complete ==
(ssl->s3->previous_server_finished_len != 0));
/* Parse out the extension contents. */
CBS renegotiated_connection;
if (!CBS_get_u8_length_prefixed(contents, &renegotiated_connection) ||
CBS_len(contents) != 0) {
OPENSSL_PUT_ERROR(SSL, SSL_R_RENEGOTIATION_ENCODING_ERR);
*out_alert = SSL_AD_ILLEGAL_PARAMETER;
return 0;
}
/* Check that the extension matches. */
if (CBS_len(&renegotiated_connection) != expected_len) {
OPENSSL_PUT_ERROR(SSL, SSL_R_RENEGOTIATION_MISMATCH);
*out_alert = SSL_AD_HANDSHAKE_FAILURE;
return 0;
}
const uint8_t *d = CBS_data(&renegotiated_connection);
if (CRYPTO_memcmp(d, ssl->s3->previous_client_finished,
ssl->s3->previous_client_finished_len)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_RENEGOTIATION_MISMATCH);
*out_alert = SSL_AD_HANDSHAKE_FAILURE;
return 0;
}
d += ssl->s3->previous_client_finished_len;
if (CRYPTO_memcmp(d, ssl->s3->previous_server_finished,
ssl->s3->previous_server_finished_len)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_RENEGOTIATION_MISMATCH);
*out_alert = SSL_AD_ILLEGAL_PARAMETER;
return 0;
}
ssl->s3->send_connection_binding = 1;
return 1;
}
static int ext_ri_parse_clienthello(SSL_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 (ssl3_protocol_version(ssl) >= TLS1_3_VERSION) {
return 1;
}
if (contents == NULL) {
return 1;
}
CBS renegotiated_connection;
if (!CBS_get_u8_length_prefixed(contents, &renegotiated_connection) ||
CBS_len(contents) != 0) {
OPENSSL_PUT_ERROR(SSL, SSL_R_RENEGOTIATION_ENCODING_ERR);
return 0;
}
/* Check that the extension matches. We do not support renegotiation as a
* server, so this must be empty. */
if (CBS_len(&renegotiated_connection) != 0) {
OPENSSL_PUT_ERROR(SSL, SSL_R_RENEGOTIATION_MISMATCH);
*out_alert = SSL_AD_HANDSHAKE_FAILURE;
return 0;
}
ssl->s3->send_connection_binding = 1;
return 1;
}
static int ext_ri_add_serverhello(SSL_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 (ssl3_protocol_version(ssl) >= TLS1_3_VERSION) {
return 1;
}
if (!CBB_add_u16(out, TLSEXT_TYPE_renegotiate) ||
!CBB_add_u16(out, 1 /* length */) ||
!CBB_add_u8(out, 0 /* empty renegotiation info */)) {
return 0;
}
return 1;
}
/* Extended Master Secret.
*
* https://tools.ietf.org/html/rfc7627 */
static int ext_ems_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) {
uint16_t min_version, max_version;
if (!ssl_get_version_range(hs->ssl, &min_version, &max_version)) {
return 0;
}
/* Extended master secret is not necessary in TLS 1.3. */
if (min_version >= TLS1_3_VERSION || max_version <= SSL3_VERSION) {
return 1;
}
if (!CBB_add_u16(out, TLSEXT_TYPE_extended_master_secret) ||
!CBB_add_u16(out, 0 /* length */)) {
return 0;
}
return 1;
}
static int ext_ems_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t *out_alert,
CBS *contents) {
SSL *const ssl = hs->ssl;
if (contents != NULL) {
if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION ||
ssl->version == SSL3_VERSION ||
CBS_len(contents) != 0) {
return 0;
}
hs->extended_master_secret = 1;
}
/* Whether EMS is negotiated may not change on renegotiation. */
if (ssl->s3->established_session != NULL &&
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 0;
}
return 1;
}
static int ext_ems_parse_clienthello(SSL_HANDSHAKE *hs, uint8_t *out_alert,
CBS *contents) {
uint16_t version = ssl3_protocol_version(hs->ssl);
if (version >= TLS1_3_VERSION ||
version == SSL3_VERSION) {
return 1;
}
if (contents == NULL) {
return 1;
}
if (CBS_len(contents) != 0) {
return 0;
}
hs->extended_master_secret = 1;
return 1;
}
static int ext_ems_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) {
if (!hs->extended_master_secret) {
return 1;
}
if (!CBB_add_u16(out, TLSEXT_TYPE_extended_master_secret) ||
!CBB_add_u16(out, 0 /* length */)) {
return 0;
}
return 1;
}
/* Session tickets.
*
* https://tools.ietf.org/html/rfc5077 */
static int ext_ticket_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) {
SSL *const ssl = hs->ssl;
uint16_t min_version, max_version;
if (!ssl_get_version_range(ssl, &min_version, &max_version)) {
return 0;
}
/* TLS 1.3 uses a different ticket extension. */
if (min_version >= TLS1_3_VERSION ||
SSL_get_options(ssl) & SSL_OP_NO_TICKET) {
return 1;
}
const uint8_t *ticket_data = NULL;
int ticket_len = 0;
/* Renegotiation does not participate in session resumption. However, still
* advertise the extension to avoid potentially breaking servers which carry
* over the state from the previous handshake, such as OpenSSL servers
* without upstream's 3c3f0259238594d77264a78944d409f2127642c4. */
uint16_t session_version;
if (!ssl->s3->initial_handshake_complete &&
ssl->session != NULL &&
ssl->session->tlsext_tick != NULL &&
/* Don't send TLS 1.3 session tickets in the ticket extension. */
ssl->method->version_from_wire(&session_version,
ssl->session->ssl_version) &&
session_version < TLS1_3_VERSION) {
ticket_data = ssl->session->tlsext_tick;
ticket_len = ssl->session->tlsext_ticklen;
}
CBB ticket;
if (!CBB_add_u16(out, TLSEXT_TYPE_session_ticket) ||
!CBB_add_u16_length_prefixed(out, &ticket) ||
!CBB_add_bytes(&ticket, ticket_data, ticket_len) ||
!CBB_flush(out)) {
return 0;
}
return 1;
}
static int ext_ticket_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t *out_alert,
CBS *contents) {
SSL *const ssl = hs->ssl;
if (contents == NULL) {
return 1;
}
if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION) {
return 0;
}
/* If |SSL_OP_NO_TICKET| is set then no extension will have been sent and
* this function should never be called, even if the server tries to send the
* extension. */
assert((SSL_get_options(ssl) & SSL_OP_NO_TICKET) == 0);
if (CBS_len(contents) != 0) {
return 0;
}
hs->ticket_expected = 1;
return 1;
}
static int ext_ticket_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) {
if (!hs->ticket_expected) {
return 1;
}
/* 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 0;
}
return 1;
}
/* Signature Algorithms.
*
* https://tools.ietf.org/html/rfc5246#section-7.4.1.4.1 */
static int ext_sigalgs_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) {
SSL *const ssl = hs->ssl;
uint16_t min_version, max_version;
if (!ssl_get_version_range(ssl, &min_version, &max_version)) {
return 0;
}
if (max_version < TLS1_2_VERSION) {
return 1;
}
CBB contents, 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 0;
}
return 1;
}
static int ext_sigalgs_parse_clienthello(SSL_HANDSHAKE *hs, uint8_t *out_alert,
CBS *contents) {
OPENSSL_free(hs->peer_sigalgs);
hs->peer_sigalgs = NULL;
hs->num_peer_sigalgs = 0;
if (contents == NULL) {
return 1;
}
CBS supported_signature_algorithms;
if (!CBS_get_u16_length_prefixed(contents, &supported_signature_algorithms) ||
CBS_len(contents) != 0 ||
CBS_len(&supported_signature_algorithms) == 0 ||
!tls1_parse_peer_sigalgs(hs, &supported_signature_algorithms)) {
return 0;
}
return 1;
}
/* OCSP Stapling.
*
* https://tools.ietf.org/html/rfc6066#section-8 */
static int ext_ocsp_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) {
SSL *const ssl = hs->ssl;
if (!ssl->ocsp_stapling_enabled) {
return 1;
}
CBB contents;
if (!CBB_add_u16(out, TLSEXT_TYPE_status_request) ||
!CBB_add_u16_length_prefixed(out, &contents) ||
!CBB_add_u8(&contents, TLSEXT_STATUSTYPE_ocsp) ||
!CBB_add_u16(&contents, 0 /* empty responder ID list */) ||
!CBB_add_u16(&contents, 0 /* empty request extensions */) ||
!CBB_flush(out)) {
return 0;
}
return 1;
}
static int ext_ocsp_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t *out_alert,
CBS *contents) {
SSL *const ssl = hs->ssl;
if (contents == NULL) {
return 1;
}
/* TLS 1.3 OCSP responses are included in the Certificate extensions. */
if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION) {
return 0;
}
/* OCSP stapling is forbidden on non-certificate ciphers. */
if (CBS_len(contents) != 0 ||
!ssl_cipher_uses_certificate_auth(hs->new_cipher)) {
return 0;
}
/* Note this does not check for resumption in TLS 1.2. Sending
* status_request here does not make sense, but OpenSSL does so and the
* specification does not say anything. Tolerate it but ignore it. */
hs->certificate_status_expected = 1;
return 1;
}
static int ext_ocsp_parse_clienthello(SSL_HANDSHAKE *hs, uint8_t *out_alert,
CBS *contents) {
if (contents == NULL) {
return 1;
}
uint8_t status_type;
if (!CBS_get_u8(contents, &status_type)) {
return 0;
}
/* We cannot decide whether OCSP stapling will occur yet because the correct
* SSL_CTX might not have been selected. */
hs->ocsp_stapling_requested = status_type == TLSEXT_STATUSTYPE_ocsp;
return 1;
}
static int ext_ocsp_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) {
SSL *const ssl = hs->ssl;
if (ssl3_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 1;
}
hs->certificate_status_expected = 1;
return CBB_add_u16(out, TLSEXT_TYPE_status_request) &&
CBB_add_u16(out, 0 /* length */);
}
/* Next protocol negotiation.
*
* https://htmlpreview.github.io/?https://github.com/agl/technotes/blob/master/nextprotoneg.html */
static int 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 1;
}
if (!CBB_add_u16(out, TLSEXT_TYPE_next_proto_neg) ||
!CBB_add_u16(out, 0 /* length */)) {
return 0;
}
return 1;
}
static int ext_npn_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t *out_alert,
CBS *contents) {
SSL *const ssl = hs->ssl;
if (contents == NULL) {
return 1;
}
if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION) {
return 0;
}
/* If any of these are false then we should never have sent the NPN
* extension in the ClientHello and thus this function should never have been
* called. */
assert(!ssl->s3->initial_handshake_complete);
assert(!SSL_is_dtls(ssl));
assert(ssl->ctx->next_proto_select_cb != NULL);
if (ssl->s3->alpn_selected != NULL) {
/* NPN and ALPN may not be negotiated in the same connection. */
*out_alert = SSL_AD_ILLEGAL_PARAMETER;
OPENSSL_PUT_ERROR(SSL, SSL_R_NEGOTIATED_BOTH_NPN_AND_ALPN);
return 0;
}
const uint8_t *const orig_contents = CBS_data(contents);
const size_t orig_len = CBS_len(contents);
while (CBS_len(contents) != 0) {
CBS proto;
if (!CBS_get_u8_length_prefixed(contents, &proto) ||
CBS_len(&proto) == 0) {
return 0;
}
}
uint8_t *selected;
uint8_t selected_len;
if (ssl->ctx->next_proto_select_cb(
ssl, &selected, &selected_len, orig_contents, orig_len,
ssl->ctx->next_proto_select_cb_arg) != SSL_TLSEXT_ERR_OK) {
*out_alert = SSL_AD_INTERNAL_ERROR;
return 0;
}
OPENSSL_free(ssl->s3->next_proto_negotiated);
ssl->s3->next_proto_negotiated = BUF_memdup(selected, selected_len);
if (ssl->s3->next_proto_negotiated == NULL) {
*out_alert = SSL_AD_INTERNAL_ERROR;
return 0;
}
ssl->s3->next_proto_negotiated_len = selected_len;
hs->next_proto_neg_seen = 1;
return 1;
}
static int ext_npn_parse_clienthello(SSL_HANDSHAKE *hs, uint8_t *out_alert,
CBS *contents) {
SSL *const ssl = hs->ssl;
if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION) {
return 1;
}
if (contents != NULL && CBS_len(contents) != 0) {
return 0;
}
if (contents == NULL ||
ssl->s3->initial_handshake_complete ||
ssl->ctx->next_protos_advertised_cb == NULL ||
SSL_is_dtls(ssl)) {
return 1;
}
hs->next_proto_neg_seen = 1;
return 1;
}
static int 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 1;
}
const uint8_t *npa;
unsigned npa_len;
if (ssl->ctx->next_protos_advertised_cb(
ssl, &npa, &npa_len, ssl->ctx->next_protos_advertised_cb_arg) !=
SSL_TLSEXT_ERR_OK) {
hs->next_proto_neg_seen = 0;
return 1;
}
CBB contents;
if (!CBB_add_u16(out, TLSEXT_TYPE_next_proto_neg) ||
!CBB_add_u16_length_prefixed(out, &contents) ||
!CBB_add_bytes(&contents, npa, npa_len) ||
!CBB_flush(out)) {
return 0;
}
return 1;
}
/* Signed certificate timestamps.
*
* https://tools.ietf.org/html/rfc6962#section-3.3.1 */
static int ext_sct_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) {
SSL *const ssl = hs->ssl;
if (!ssl->signed_cert_timestamps_enabled) {
return 1;
}
if (!CBB_add_u16(out, TLSEXT_TYPE_certificate_timestamp) ||
!CBB_add_u16(out, 0 /* length */)) {
return 0;
}
return 1;
}
static int ext_sct_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t *out_alert,
CBS *contents) {
SSL *const ssl = hs->ssl;
if (contents == NULL) {
return 1;
}
/* TLS 1.3 SCTs are included in the Certificate extensions. */
if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION) {
*out_alert = SSL_AD_DECODE_ERROR;
return 0;
}
/* 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 0;
}
/* Session resumption uses the original session information. The extension
* should not be sent on resumption, but RFC 6962 did not make it a
* requirement, so tolerate this.
*
* TODO(davidben): Enforce this anyway. */
if (!ssl->s3->session_reused &&
!CBS_stow(contents, &hs->new_session->tlsext_signed_cert_timestamp_list,
&hs->new_session->tlsext_signed_cert_timestamp_list_length)) {
*out_alert = SSL_AD_INTERNAL_ERROR;
return 0;
}
return 1;
}
static int ext_sct_parse_clienthello(SSL_HANDSHAKE *hs, uint8_t *out_alert,
CBS *contents) {
if (contents == NULL) {
return 1;
}
if (CBS_len(contents) != 0) {
return 0;
}
hs->scts_requested = 1;
return 1;
}
static int ext_sct_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) {
SSL *const ssl = hs->ssl;
/* The extension shouldn't be sent when resuming sessions. */
if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION ||
ssl->s3->session_reused ||
ssl->cert->signed_cert_timestamp_list == NULL) {
return 1;
}
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 int 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 1;
}
CBB contents, proto_list;
if (!CBB_add_u16(out, TLSEXT_TYPE_application_layer_protocol_negotiation) ||
!CBB_add_u16_length_prefixed(out, &contents) ||
!CBB_add_u16_length_prefixed(&contents, &proto_list) ||
!CBB_add_bytes(&proto_list, ssl->alpn_client_proto_list,
ssl->alpn_client_proto_list_len) ||
!CBB_flush(out)) {
return 0;
}
return 1;
}
static int ext_alpn_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t *out_alert,
CBS *contents) {
SSL *const ssl = hs->ssl;
if (contents == NULL) {
return 1;
}
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 0;
}
/* The extension data consists of a ProtocolNameList which must have
* exactly one ProtocolName. Each of these is length-prefixed. */
CBS protocol_name_list, protocol_name;
if (!CBS_get_u16_length_prefixed(contents, &protocol_name_list) ||
CBS_len(contents) != 0 ||
!CBS_get_u8_length_prefixed(&protocol_name_list, &protocol_name) ||
/* Empty protocol names are forbidden. */
CBS_len(&protocol_name) == 0 ||
CBS_len(&protocol_name_list) != 0) {
return 0;
}
if (!ssl->ctx->allow_unknown_alpn_protos) {
/* Check that the protocol name is one of the ones we advertised. */
int protocol_ok = 0;
CBS client_protocol_name_list, client_protocol_name;
CBS_init(&client_protocol_name_list, ssl->alpn_client_proto_list,
ssl->alpn_client_proto_list_len);
while (CBS_len(&client_protocol_name_list) > 0) {
if (!CBS_get_u8_length_prefixed(&client_protocol_name_list,
&client_protocol_name)) {
*out_alert = SSL_AD_INTERNAL_ERROR;
return 0;
}
if (CBS_len(&client_protocol_name) == CBS_len(&protocol_name) &&
OPENSSL_memcmp(CBS_data(&client_protocol_name),
CBS_data(&protocol_name),
CBS_len(&protocol_name)) == 0) {
protocol_ok = 1;
break;
}
}
if (!protocol_ok) {
OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_ALPN_PROTOCOL);
*out_alert = SSL_AD_ILLEGAL_PARAMETER;
return 0;
}
}
if (!CBS_stow(&protocol_name, &ssl->s3->alpn_selected,
&ssl->s3->alpn_selected_len)) {
*out_alert = SSL_AD_INTERNAL_ERROR;
return 0;
}
return 1;
}
int ssl_negotiate_alpn(SSL_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 1;
}
/* ALPN takes precedence over NPN. */
hs->next_proto_neg_seen = 0;
CBS protocol_name_list;
if (!CBS_get_u16_length_prefixed(&contents, &protocol_name_list) ||
CBS_len(&contents) != 0 ||
CBS_len(&protocol_name_list) < 2) {
OPENSSL_PUT_ERROR(SSL, SSL_R_PARSE_TLSEXT);
*out_alert = SSL_AD_DECODE_ERROR;
return 0;
}
/* Validate the protocol list. */
CBS protocol_name_list_copy = protocol_name_list;
while (CBS_len(&protocol_name_list_copy) > 0) {
CBS protocol_name;
if (!CBS_get_u8_length_prefixed(&protocol_name_list_copy, &protocol_name) ||
/* Empty protocol names are forbidden. */
CBS_len(&protocol_name) == 0) {
OPENSSL_PUT_ERROR(SSL, SSL_R_PARSE_TLSEXT);
*out_alert = SSL_AD_DECODE_ERROR;
return 0;
}
}
const uint8_t *selected;
uint8_t selected_len;
if (ssl->ctx->alpn_select_cb(
ssl, &selected, &selected_len, CBS_data(&protocol_name_list),
CBS_len(&protocol_name_list),
ssl->ctx->alpn_select_cb_arg) == SSL_TLSEXT_ERR_OK) {
OPENSSL_free(ssl->s3->alpn_selected);
ssl->s3->alpn_selected = BUF_memdup(selected, selected_len);
if (ssl->s3->alpn_selected == NULL) {
*out_alert = SSL_AD_INTERNAL_ERROR;
return 0;
}
ssl->s3->alpn_selected_len = selected_len;
}
return 1;
}
static int ext_alpn_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) {
SSL *const ssl = hs->ssl;
if (ssl->s3->alpn_selected == NULL) {
return 1;
}
CBB contents, proto_list, proto;
if (!CBB_add_u16(out, TLSEXT_TYPE_application_layer_protocol_negotiation) ||
!CBB_add_u16_length_prefixed(out, &contents) ||
!CBB_add_u16_length_prefixed(&contents, &proto_list) ||
!CBB_add_u8_length_prefixed(&proto_list, &proto) ||
!CBB_add_bytes(&proto, ssl->s3->alpn_selected,
ssl->s3->alpn_selected_len) ||
!CBB_flush(out)) {
return 0;
}
return 1;
}
/* Channel ID.
*
* https://tools.ietf.org/html/draft-balfanz-tls-channelid-01 */
static void ext_channel_id_init(SSL_HANDSHAKE *hs) {
hs->ssl->s3->tlsext_channel_id_valid = 0;
}
static int 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 1;
}
if (!CBB_add_u16(out, TLSEXT_TYPE_channel_id) ||
!CBB_add_u16(out, 0 /* length */)) {
return 0;
}
return 1;
}
static int ext_channel_id_parse_serverhello(SSL_HANDSHAKE *hs,
uint8_t *out_alert, CBS *contents) {
SSL *const ssl = hs->ssl;
if (contents == NULL) {
return 1;
}
assert(!SSL_is_dtls(ssl));
assert(ssl->tlsext_channel_id_enabled);
if (CBS_len(contents) != 0) {
return 0;
}
ssl->s3->tlsext_channel_id_valid = 1;
return 1;
}
static int ext_channel_id_parse_clienthello(SSL_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 1;
}
if (CBS_len(contents) != 0) {
return 0;
}
ssl->s3->tlsext_channel_id_valid = 1;
return 1;
}
static int ext_channel_id_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) {
SSL *const ssl = hs->ssl;
if (!ssl->s3->tlsext_channel_id_valid) {
return 1;
}
if (!CBB_add_u16(out, TLSEXT_TYPE_channel_id) ||
!CBB_add_u16(out, 0 /* length */)) {
return 0;
}
return 1;
}
/* Secure Real-time Transport Protocol (SRTP) extension.
*
* https://tools.ietf.org/html/rfc5764 */
static void ext_srtp_init(SSL_HANDSHAKE *hs) {
hs->ssl->srtp_profile = NULL;
}
static int 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) {
return 1;
}
const size_t num_profiles = sk_SRTP_PROTECTION_PROFILE_num(profiles);
if (num_profiles == 0) {
return 1;
}
CBB contents, profile_ids;
if (!CBB_add_u16(out, TLSEXT_TYPE_srtp) ||
!CBB_add_u16_length_prefixed(out, &contents) ||
!CBB_add_u16_length_prefixed(&contents, &profile_ids)) {
return 0;
}
for (size_t i = 0; i < num_profiles; i++) {
if (!CBB_add_u16(&profile_ids,
sk_SRTP_PROTECTION_PROFILE_value(profiles, i)->id)) {
return 0;
}
}
if (!CBB_add_u8(&contents, 0 /* empty use_mki value */) ||
!CBB_flush(out)) {
return 0;
}
return 1;
}
static int ext_srtp_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t *out_alert,
CBS *contents) {
SSL *const ssl = hs->ssl;
if (contents == NULL) {
return 1;
}
/* The extension consists of a u16-prefixed profile ID list containing a
* single uint16_t profile ID, then followed by a u8-prefixed srtp_mki field.
*
* See https://tools.ietf.org/html/rfc5764#section-4.1.1 */
CBS profile_ids, srtp_mki;
uint16_t profile_id;
if (!CBS_get_u16_length_prefixed(contents, &profile_ids) ||
!CBS_get_u16(&profile_ids, &profile_id) ||
CBS_len(&profile_ids) != 0 ||
!CBS_get_u8_length_prefixed(contents, &srtp_mki) ||
CBS_len(contents) != 0) {
OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
return 0;
}
if (CBS_len(&srtp_mki) != 0) {
/* Must be no MKI, since we never offer one. */
OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_SRTP_MKI_VALUE);
*out_alert = SSL_AD_ILLEGAL_PARAMETER;
return 0;
}
STACK_OF(SRTP_PROTECTION_PROFILE) *profiles = SSL_get_srtp_profiles(ssl);
/* Check to see if the server gave us something we support (and presumably
* offered). */
for (size_t i = 0; i < sk_SRTP_PROTECTION_PROFILE_num(profiles); i++) {
const SRTP_PROTECTION_PROFILE *profile =
sk_SRTP_PROTECTION_PROFILE_value(profiles, i);
if (profile->id == profile_id) {
ssl->srtp_profile = profile;
return 1;
}
}
OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
*out_alert = SSL_AD_ILLEGAL_PARAMETER;
return 0;
}
static int ext_srtp_parse_clienthello(SSL_HANDSHAKE *hs, uint8_t *out_alert,
CBS *contents) {
SSL *const ssl = hs->ssl;
if (contents == NULL) {
return 1;
}
CBS profile_ids, srtp_mki;
if (!CBS_get_u16_length_prefixed(contents, &profile_ids) ||
CBS_len(&profile_ids) < 2 ||
!CBS_get_u8_length_prefixed(contents, &srtp_mki) ||
CBS_len(contents) != 0) {
OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
return 0;
}
/* Discard the MKI value for now. */
const STACK_OF(SRTP_PROTECTION_PROFILE) *server_profiles =
SSL_get_srtp_profiles(ssl);
/* Pick the server's most preferred profile. */
for (size_t i = 0; i < sk_SRTP_PROTECTION_PROFILE_num(server_profiles); i++) {
const SRTP_PROTECTION_PROFILE *server_profile =
sk_SRTP_PROTECTION_PROFILE_value(server_profiles, i);
CBS profile_ids_tmp;
CBS_init(&profile_ids_tmp, CBS_data(&profile_ids), CBS_len(&profile_ids));
while (CBS_len(&profile_ids_tmp) > 0) {
uint16_t profile_id;
if (!CBS_get_u16(&profile_ids_tmp, &profile_id)) {
return 0;
}
if (server_profile->id == profile_id) {
ssl->srtp_profile = server_profile;
return 1;
}
}
}
return 1;
}
static int ext_srtp_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) {
SSL *const ssl = hs->ssl;
if (ssl->srtp_profile == NULL) {
return 1;
}
CBB contents, profile_ids;
if (!CBB_add_u16(out, TLSEXT_TYPE_srtp) ||
!CBB_add_u16_length_prefixed(out, &contents) ||
!CBB_add_u16_length_prefixed(&contents, &profile_ids) ||
!CBB_add_u16(&profile_ids, ssl->srtp_profile->id) ||
!CBB_add_u8(&contents, 0 /* empty MKI */) ||
!CBB_flush(out)) {
return 0;
}
return 1;
}
/* EC point formats.
*
* https://tools.ietf.org/html/rfc4492#section-5.1.2 */
static int ext_ec_point_add_extension(SSL_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 0;
}
return 1;
}
static int ext_ec_point_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) {
uint16_t min_version, max_version;
if (!ssl_get_version_range(hs->ssl, &min_version, &max_version)) {
return 0;
}
/* The point format extension is unneccessary in TLS 1.3. */
if (min_version >= TLS1_3_VERSION) {
return 1;
}
return ext_ec_point_add_extension(hs, out);
}
static int ext_ec_point_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t *out_alert,
CBS *contents) {
if (contents == NULL) {
return 1;
}
if (ssl3_protocol_version(hs->ssl) >= TLS1_3_VERSION) {
return 0;
}
CBS ec_point_format_list;
if (!CBS_get_u8_length_prefixed(contents, &ec_point_format_list) ||
CBS_len(contents) != 0) {
return 0;
}
/* Per RFC 4492, section 5.1.2, implementations MUST support the uncompressed
* point format. */
if (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 0;
}
return 1;
}
static int ext_ec_point_parse_clienthello(SSL_HANDSHAKE *hs, uint8_t *out_alert,
CBS *contents) {
if (ssl3_protocol_version(hs->ssl) >= TLS1_3_VERSION) {
return 1;
}
return ext_ec_point_parse_serverhello(hs, out_alert, contents);
}
static int ext_ec_point_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) {
SSL *const ssl = hs->ssl;
if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION) {
return 1;
}
const uint32_t alg_k = hs->new_cipher->algorithm_mkey;
const uint32_t alg_a = hs->new_cipher->algorithm_auth;
const int using_ecc = (alg_k & SSL_kECDHE) || (alg_a & SSL_aECDSA);
if (!using_ecc) {
return 1;
}
return ext_ec_point_add_extension(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;
uint16_t min_version, max_version;
if (!ssl_get_version_range(ssl, &min_version, &max_version)) {
return 0;
}
uint16_t session_version;
if (max_version < TLS1_3_VERSION || ssl->session == NULL ||
!ssl->method->version_from_wire(&session_version,
ssl->session->ssl_version) ||
session_version < TLS1_3_VERSION) {
return 0;
}
const EVP_MD *digest = SSL_SESSION_get_digest(ssl->session, ssl);
if (digest == NULL) {
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
return 0;
}
size_t binder_len = EVP_MD_size(digest);
return 15 + ssl->session->tlsext_ticklen + binder_len;
}
static int ext_pre_shared_key_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) {
SSL *const ssl = hs->ssl;
uint16_t min_version, max_version;
if (!ssl_get_version_range(ssl, &min_version, &max_version)) {
return 0;
}
uint16_t session_version;
if (max_version < TLS1_3_VERSION || ssl->session == NULL ||
!ssl->method->version_from_wire(&session_version,
ssl->session->ssl_version) ||
session_version < TLS1_3_VERSION) {
return 1;
}
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};
const EVP_MD *digest = SSL_SESSION_get_digest(ssl->session, ssl);
if (digest == NULL) {
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
return 0;
}
size_t binder_len = EVP_MD_size(digest);
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 0;
}
hs->needs_psk_binder = 1;
return CBB_flush(out);
}
int 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 0;
}
/* We only advertise one PSK identity, so the only legal index is zero. */
if (psk_id != 0) {
OPENSSL_PUT_ERROR(SSL, SSL_R_PSK_IDENTITY_NOT_FOUND);
*out_alert = SSL_AD_UNKNOWN_PSK_IDENTITY;
return 0;
}
return 1;
}
int ssl_ext_pre_shared_key_parse_clienthello(
SSL_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 0;
}
*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 0;
}
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 0;
}
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 0;
}
return 1;
}
int ssl_ext_pre_shared_key_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) {
if (!hs->ssl->s3->session_reused) {
return 1;
}
CBB contents;
if (!CBB_add_u16(out, TLSEXT_TYPE_pre_shared_key) ||
!CBB_add_u16_length_prefixed(out, &contents) ||
/* We only consider the first identity for resumption */
!CBB_add_u16(&contents, 0) ||
!CBB_flush(out)) {
return 0;
}
return 1;
}
/* Pre-Shared Key Exchange Modes
*
* https://tools.ietf.org/html/draft-ietf-tls-tls13-18#section-4.2.7 */
static int ext_psk_key_exchange_modes_add_clienthello(SSL_HANDSHAKE *hs,
CBB *out) {
SSL *const ssl = hs->ssl;
uint16_t min_version, max_version;
if (!ssl_get_version_range(ssl, &min_version, &max_version)) {
return 0;
}
if (max_version < TLS1_3_VERSION) {
return 1;
}
CBB contents, 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 0;
}
return CBB_flush(out);
}
static int ext_psk_key_exchange_modes_parse_clienthello(SSL_HANDSHAKE *hs,
uint8_t *out_alert,
CBS *contents) {
if (contents == NULL) {
return 1;
}
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 0;
}
/* 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 1;
}
/* Early Data Indication
*
* https://tools.ietf.org/html/draft-ietf-tls-tls13-18#section-4.2.8 */
static int ext_early_data_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) {
SSL *const ssl = hs->ssl;
uint16_t session_version;
if (ssl->session == NULL ||
!ssl->method->version_from_wire(&session_version,
ssl->session->ssl_version) ||
session_version < TLS1_3_VERSION ||
ssl->session->ticket_max_early_data == 0 ||
hs->received_hello_retry_request ||
!ssl->cert->enable_early_data) {
return 1;
}
hs->early_data_offered = 1;
if (!CBB_add_u16(out, TLSEXT_TYPE_early_data) ||
!CBB_add_u16(out, 0) ||
!CBB_flush(out)) {
return 0;
}
return 1;
}
static int ext_early_data_parse_serverhello(SSL_HANDSHAKE *hs,
uint8_t *out_alert, CBS *contents) {
SSL *const ssl = hs->ssl;
if (contents == NULL) {
return 1;
}
if (CBS_len(contents) != 0) {
*out_alert = SSL_AD_DECODE_ERROR;
return 0;
}
if (!ssl->s3->session_reused) {
*out_alert = SSL_AD_UNSUPPORTED_EXTENSION;
OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_EXTENSION);
return 0;
}
ssl->early_data_accepted = 1;
return 1;
}
static int ext_early_data_parse_clienthello(SSL_HANDSHAKE *hs,
uint8_t *out_alert, CBS *contents) {
SSL *const ssl = hs->ssl;
if (contents == NULL ||
ssl3_protocol_version(ssl) < TLS1_3_VERSION) {
return 1;
}
if (CBS_len(contents) != 0) {
*out_alert = SSL_AD_DECODE_ERROR;
return 0;
}
hs->early_data_offered = 1;
return 1;
}
static int ext_early_data_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) {
if (!hs->ssl->early_data_accepted) {
return 1;
}
if (!CBB_add_u16(out, TLSEXT_TYPE_early_data) ||
!CBB_add_u16(out, 0) ||
!CBB_flush(out)) {
return 0;
}
return 1;
}
/* Key Share
*
* https://tools.ietf.org/html/draft-ietf-tls-tls13-16#section-4.2.5 */
static int ext_key_share_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) {
SSL *const ssl = hs->ssl;
uint16_t min_version, max_version;
if (!ssl_get_version_range(ssl, &min_version, &max_version)) {
return 0;
}
if (max_version < TLS1_3_VERSION) {
return 1;
}
CBB contents, kse_bytes;
if (!CBB_add_u16(out, TLSEXT_TYPE_key_share) ||
!CBB_add_u16_length_prefixed(out, &contents) ||
!CBB_add_u16_length_prefixed(&contents, &kse_bytes)) {
return 0;
}
uint16_t group_id = 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 |ecdh_ctx| as-is. */
if (group_id == 0 &&
!CBB_add_bytes(&kse_bytes, hs->key_share_bytes,
hs->key_share_bytes_len)) {
return 0;
}
OPENSSL_free(hs->key_share_bytes);
hs->key_share_bytes = NULL;
hs->key_share_bytes_len = 0;
if (group_id == 0) {
return CBB_flush(out);
}
} else {
/* Add a fake group. See draft-davidben-tls-grease-01. */
if (ssl->ctx->grease_enabled &&
(!CBB_add_u16(&kse_bytes,
ssl_get_grease_value(ssl, ssl_grease_group)) ||
!CBB_add_u16(&kse_bytes, 1 /* length */) ||
!CBB_add_u8(&kse_bytes, 0 /* one byte key share */))) {
return 0;
}
/* Predict the most preferred group. */
const uint16_t *groups;
size_t groups_len;
tls1_get_grouplist(ssl, &groups, &groups_len);
if (groups_len == 0) {
OPENSSL_PUT_ERROR(SSL, SSL_R_NO_GROUPS_SPECIFIED);
return 0;
}
group_id = groups[0];
}
CBB key_exchange;
if (!CBB_add_u16(&kse_bytes, group_id) ||
!CBB_add_u16_length_prefixed(&kse_bytes, &key_exchange) ||
!SSL_ECDH_CTX_init(&hs->ecdh_ctx, group_id) ||
!SSL_ECDH_CTX_offer(&hs->ecdh_ctx, &key_exchange) ||
!CBB_flush(&kse_bytes)) {
return 0;
}
if (!hs->received_hello_retry_request) {
/* Save the contents of the extension to repeat it in the second
* ClientHello. */
hs->key_share_bytes_len = CBB_len(&kse_bytes);
hs->key_share_bytes = BUF_memdup(CBB_data(&kse_bytes), CBB_len(&kse_bytes));
if (hs->key_share_bytes == NULL) {
return 0;
}
}
return CBB_flush(out);
}
int ssl_ext_key_share_parse_serverhello(SSL_HANDSHAKE *hs, uint8_t **out_secret,
size_t *out_secret_len,
uint8_t *out_alert, CBS *contents) {
CBS peer_key;
uint16_t group_id;
if (!CBS_get_u16(contents, &group_id) ||
!CBS_get_u16_length_prefixed(contents, &peer_key) ||
CBS_len(contents) != 0) {
*out_alert = SSL_AD_DECODE_ERROR;
return 0;
}
if (SSL_ECDH_CTX_get_id(&hs->ecdh_ctx) != group_id) {
*out_alert = SSL_AD_ILLEGAL_PARAMETER;
OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_CURVE);
return 0;
}
if (!SSL_ECDH_CTX_finish(&hs->ecdh_ctx, out_secret, out_secret_len, out_alert,
CBS_data(&peer_key), CBS_len(&peer_key))) {
*out_alert = SSL_AD_INTERNAL_ERROR;
return 0;
}
hs->new_session->group_id = group_id;
SSL_ECDH_CTX_cleanup(&hs->ecdh_ctx);
return 1;
}
int ssl_ext_key_share_parse_clienthello(SSL_HANDSHAKE *hs, int *out_found,
uint8_t **out_secret,
size_t *out_secret_len,
uint8_t *out_alert, CBS *contents) {
uint16_t group_id;
CBS key_shares;
if (!tls1_get_shared_group(hs, &group_id)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_NO_SHARED_GROUP);
*out_alert = SSL_AD_HANDSHAKE_FAILURE;
return 0;
}
if (!CBS_get_u16_length_prefixed(contents, &key_shares) ||
CBS_len(contents) != 0) {
OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
return 0;
}
/* Find the corresponding key share. */
int found = 0;
CBS peer_key;
while (CBS_len(&key_shares) > 0) {
uint16_t id;
CBS peer_key_tmp;
if (!CBS_get_u16(&key_shares, &id) ||
!CBS_get_u16_length_prefixed(&key_shares, &peer_key_tmp)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
return 0;
}
if (id == group_id) {
if (found) {
OPENSSL_PUT_ERROR(SSL, SSL_R_DUPLICATE_KEY_SHARE);
*out_alert = SSL_AD_ILLEGAL_PARAMETER;
return 0;
}
found = 1;
peer_key = peer_key_tmp;
/* Continue parsing the structure to keep peers honest. */
}
}
if (!found) {
*out_found = 0;
*out_secret = NULL;
*out_secret_len = 0;
return 1;
}
/* Compute the DH secret. */
uint8_t *secret = NULL;
size_t secret_len;
SSL_ECDH_CTX group;
OPENSSL_memset(&group, 0, sizeof(SSL_ECDH_CTX));
CBB public_key;
if (!CBB_init(&public_key, 32) ||
!SSL_ECDH_CTX_init(&group, group_id) ||
!SSL_ECDH_CTX_accept(&group, &public_key, &secret, &secret_len, out_alert,
CBS_data(&peer_key), CBS_len(&peer_key)) ||
!CBB_finish(&public_key, &hs->ecdh_public_key,
&hs->ecdh_public_key_len)) {
OPENSSL_free(secret);
SSL_ECDH_CTX_cleanup(&group);
CBB_cleanup(&public_key);
*out_alert = SSL_AD_ILLEGAL_PARAMETER;
return 0;
}
SSL_ECDH_CTX_cleanup(&group);
*out_secret = secret;
*out_secret_len = secret_len;
*out_found = 1;
return 1;
}
int ssl_ext_key_share_add_serverhello(SSL_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,
hs->ecdh_public_key_len) ||
!CBB_flush(out)) {
return 0;
}
OPENSSL_free(hs->ecdh_public_key);
hs->ecdh_public_key = NULL;
hs->ecdh_public_key_len = 0;
hs->new_session->group_id = group_id;
return 1;
}
/* Supported Versions
*
* https://tools.ietf.org/html/draft-ietf-tls-tls13-16#section-4.2.1 */
static int ext_supported_versions_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) {
SSL *const ssl = hs->ssl;
uint16_t min_version, max_version;
if (!ssl_get_version_range(ssl, &min_version, &max_version)) {
return 0;
}
if (max_version <= TLS1_2_VERSION) {
return 1;
}
CBB contents, versions;
if (!CBB_add_u16(out, TLSEXT_TYPE_supported_versions) ||
!CBB_add_u16_length_prefixed(out, &contents) ||
!CBB_add_u8_length_prefixed(&contents, &versions)) {
return 0;
}
/* Add a fake version. See draft-davidben-tls-grease-01. */
if (ssl->ctx->grease_enabled &&
!CBB_add_u16(&versions, ssl_get_grease_value(ssl, ssl_grease_version))) {
return 0;
}
for (uint16_t version = max_version; version >= min_version; version--) {
if (!CBB_add_u16(&versions, ssl->method->version_to_wire(version))) {
return 0;
}
}
if (!CBB_flush(out)) {
return 0;
}
return 1;
}
/* Cookie
*
* https://tools.ietf.org/html/draft-ietf-tls-tls13-16#section-4.2.2 */
static int ext_cookie_add_clienthello(SSL_HANDSHAKE *hs, CBB *out) {
if (hs->cookie == NULL) {
return 1;
}
CBB contents, cookie;
if (!CBB_add_u16(out, TLSEXT_TYPE_cookie) ||
!CBB_add_u16_length_prefixed(out, &contents) ||
!CBB_add_u16_length_prefixed(&contents, &cookie) ||
!CBB_add_bytes(&cookie, hs->cookie, hs->cookie_len) ||
!CBB_flush(out)) {
return 0;
}
/* The cookie is no longer needed in memory. */
OPENSSL_free(hs->cookie);
hs->cookie = NULL;
hs->cookie_len = 0;
return 1;
}
/* Negotiated Groups
*
* https://tools.ietf.org/html/rfc4492#section-5.1.2
* https://tools.ietf.org/html/draft-ietf-tls-tls13-16#section-4.2.4 */
static int ext_supported_groups_add_clienthello(SSL_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 0;
}
/* Add a fake group. See draft-davidben-tls-grease-01. */
if (ssl->ctx->grease_enabled &&
!CBB_add_u16(&groups_bytes,
ssl_get_grease_value(ssl, ssl_grease_group))) {
return 0;
}
const uint16_t *groups;
size_t groups_len;
tls1_get_grouplist(ssl, &groups, &groups_len);
for (size_t i = 0; i < groups_len; i++) {
if (!CBB_add_u16(&groups_bytes, groups[i])) {
return 0;
}
}
return CBB_flush(out);
}
static int ext_supported_groups_parse_serverhello(SSL_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 1;
}
static int ext_supported_groups_parse_clienthello(SSL_HANDSHAKE *hs,
uint8_t *out_alert,
CBS *contents) {
if (contents == NULL) {
return 1;
}
CBS supported_group_list;
if (!CBS_get_u16_length_prefixed(contents, &supported_group_list) ||
CBS_len(&supported_group_list) == 0 ||
(CBS_len(&supported_group_list) & 1) != 0 ||
CBS_len(contents) != 0) {
return 0;
}
hs->peer_supported_group_list =
OPENSSL_malloc(CBS_len(&supported_group_list));
if (hs->peer_supported_group_list == NULL) {
*out_alert = SSL_AD_INTERNAL_ERROR;
return 0;
}
const size_t num_groups = CBS_len(&supported_group_list) / 2;
for (size_t i = 0; i < num_groups; i++) {
if (!CBS_get_u16(&supported_group_list,
&hs->peer_supported_group_list[i])) {
goto err;
}
}
assert(CBS_len(&supported_group_list) == 0);
hs->peer_supported_group_list_len = num_groups;
return 1;
err:
OPENSSL_free(hs->peer_supported_group_list);
hs->peer_supported_group_list = NULL;
*out_alert = SSL_AD_INTERNAL_ERROR;
return 0;
}
static int ext_supported_groups_add_serverhello(SSL_HANDSHAKE *hs, CBB *out) {
/* Servers don't echo this extension. */
return 1;
}
/* kExtensions contains all the supported extensions. */
static const struct tls_extension kExtensions[] = {
{
TLSEXT_TYPE_renegotiate,
NULL,
ext_ri_add_clienthello,
ext_ri_parse_serverhello,
ext_ri_parse_clienthello,
ext_ri_add_serverhello,
},
{
TLSEXT_TYPE_server_name,
NULL,
ext_sni_add_clienthello,
ext_sni_parse_serverhello,
ext_sni_parse_clienthello,
ext_sni_add_serverhello,
},
{
TLSEXT_TYPE_extended_master_secret,
NULL,
ext_ems_add_clienthello,
ext_ems_parse_serverhello,
ext_ems_parse_clienthello,
ext_ems_add_serverhello,
},
{
TLSEXT_TYPE_session_ticket,
NULL,
ext_ticket_add_clienthello,
ext_ticket_parse_serverhello,
/* Ticket extension client parsing is handled in ssl_session.c */
ignore_parse_clienthello,
ext_ticket_add_serverhello,
},
{
TLSEXT_TYPE_signature_algorithms,
NULL,
ext_sigalgs_add_clienthello,
forbid_parse_serverhello,
ext_sigalgs_parse_clienthello,
dont_add_serverhello,
},
{
TLSEXT_TYPE_status_request,
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,
},
/* The final extension must be non-empty. WebSphere Application Server 7.0 is
* intolerant to the last extension being zero-length. See
* https://crbug.com/363583. */
{
TLSEXT_TYPE_supported_groups,
NULL,
ext_supported_groups_add_clienthello,
ext_supported_groups_parse_serverhello,
ext_supported_groups_parse_clienthello,
ext_supported_groups_add_serverhello,
},
};
#define kNumExtensions (sizeof(kExtensions) / sizeof(struct tls_extension))
OPENSSL_COMPILE_ASSERT(kNumExtensions <=
sizeof(((SSL_HANDSHAKE *)NULL)->extensions.sent) * 8,
too_many_extensions_for_sent_bitset);
OPENSSL_COMPILE_ASSERT(
kNumExtensions <= sizeof(((SSL_HANDSHAKE *)NULL)->extensions.received) * 8,
too_many_extensions_for_received_bitset);
static const struct tls_extension *tls_extension_find(uint32_t *out_index,
uint16_t value) {
unsigned i;
for (i = 0; i < kNumExtensions; i++) {
if (kExtensions[i].value == value) {
*out_index = i;
return &kExtensions[i];
}
}
return NULL;
}
int SSL_extension_supported(unsigned extension_value) {
uint32_t index;
return extension_value == TLSEXT_TYPE_padding ||
tls_extension_find(&index, extension_value) != NULL;
}
int ssl_add_clienthello_tlsext(SSL_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;