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boringssl/ssl/t1_lib.c
Steven Valdez ce902a9bcd Generalizing curves to groups in preparation for TLS 1.3. 
The 'elliptic_curves' extension is being renamed to 'supported_groups'
in the TLS 1.3 draft, and most of the curve-specific methods are
generalized to groups/group IDs.

Change-Id: Icd1a1cf7365c8a4a64ae601993dc4273802610fb
Reviewed-on: https://boringssl-review.googlesource.com/7955
Reviewed-by: David Benjamin <davidben@google.com>
2016-05-20 17:43:11 +00:00

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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"
static int ssl_check_clienthello_tlsext(SSL *ssl);
static int ssl_check_serverhello_tlsext(SSL *ssl);
static int compare_uint16_t(const void *p1, const void *p2) {
uint16_t u1 = *((const uint16_t *)p1);
uint16_t u2 = *((const uint16_t *)p2);
if (u1 < u2) {
return -1;
} else if (u1 > u2) {
return 1;
} else {
return 0;
}
}
/* Per http://tools.ietf.org/html/rfc5246#section-7.4.1.4, there may not be
* more than one extension of the same type in a ClientHello or ServerHello.
* This function does an initial scan over the extensions block to filter those
* out. */
static int tls1_check_duplicate_extensions(const CBS *cbs) {
CBS extensions = *cbs;
size_t num_extensions = 0, i = 0;
uint16_t *extension_types = NULL;
int ret = 0;
/* First pass: count the extensions. */
while (CBS_len(&extensions) > 0) {
uint16_t type;
CBS extension;
if (!CBS_get_u16(&extensions, &type) ||
!CBS_get_u16_length_prefixed(&extensions, &extension)) {
goto done;
}
num_extensions++;
}
if (num_extensions == 0) {
return 1;
}
extension_types = OPENSSL_malloc(sizeof(uint16_t) * num_extensions);
if (extension_types == NULL) {
OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
goto done;
}
/* Second pass: gather the extension types. */
extensions = *cbs;
for (i = 0; i < num_extensions; i++) {
CBS extension;
if (!CBS_get_u16(&extensions, &extension_types[i]) ||
!CBS_get_u16_length_prefixed(&extensions, &extension)) {
/* This should not happen. */
goto done;
}
}
assert(CBS_len(&extensions) == 0);
/* Sort the extensions and make sure there are no duplicates. */
qsort(extension_types, num_extensions, sizeof(uint16_t), compare_uint16_t);
for (i = 1; i < num_extensions; i++) {
if (extension_types[i - 1] == extension_types[i]) {
goto done;
}
}
ret = 1;
done:
OPENSSL_free(extension_types);
return ret;
}
char ssl_early_callback_init(struct ssl_early_callback_ctx *ctx) {
CBS client_hello, session_id, cipher_suites, compression_methods, extensions;
CBS_init(&client_hello, ctx->client_hello, ctx->client_hello_len);
if (/* Skip client version. */
!CBS_skip(&client_hello, 2) ||
/* Skip client nonce. */
!CBS_skip(&client_hello, 32) ||
/* Extract session_id. */
!CBS_get_u8_length_prefixed(&client_hello, &session_id)) {
return 0;
}
ctx->session_id = CBS_data(&session_id);
ctx->session_id_len = CBS_len(&session_id);
/* Skip past DTLS cookie */
if (SSL_IS_DTLS(ctx->ssl)) {
CBS cookie;
if (!CBS_get_u8_length_prefixed(&client_hello, &cookie)) {
return 0;
}
}
/* Extract cipher_suites. */
if (!CBS_get_u16_length_prefixed(&client_hello, &cipher_suites) ||
CBS_len(&cipher_suites) < 2 || (CBS_len(&cipher_suites) & 1) != 0) {
return 0;
}
ctx->cipher_suites = CBS_data(&cipher_suites);
ctx->cipher_suites_len = CBS_len(&cipher_suites);
/* Extract compression_methods. */
if (!CBS_get_u8_length_prefixed(&client_hello, &compression_methods) ||
CBS_len(&compression_methods) < 1) {
return 0;
}
ctx->compression_methods = CBS_data(&compression_methods);
ctx->compression_methods_len = CBS_len(&compression_methods);
/* If the ClientHello ends here then it's valid, but doesn't have any
* extensions. (E.g. SSLv3.) */
if (CBS_len(&client_hello) == 0) {
ctx->extensions = NULL;
ctx->extensions_len = 0;
return 1;
}
/* Extract extensions and check it is valid. */
if (!CBS_get_u16_length_prefixed(&client_hello, &extensions) ||
!tls1_check_duplicate_extensions(&extensions) ||
CBS_len(&client_hello) != 0) {
return 0;
}
ctx->extensions = CBS_data(&extensions);
ctx->extensions_len = CBS_len(&extensions);
return 1;
}
int SSL_early_callback_ctx_extension_get(
const struct ssl_early_callback_ctx *ctx, uint16_t extension_type,
const uint8_t **out_data, size_t *out_len) {
CBS extensions;
CBS_init(&extensions, ctx->extensions, ctx->extensions_len);
while (CBS_len(&extensions) != 0) {
uint16_t type;
CBS extension;
/* Decode the next extension. */
if (!CBS_get_u16(&extensions, &type) ||
!CBS_get_u16_length_prefixed(&extensions, &extension)) {
return 0;
}
if (type == extension_type) {
*out_data = CBS_data(&extension);
*out_len = CBS_len(&extension);
return 1;
}
}
return 0;
}
static const uint16_t kDefaultGroups[] = {
SSL_GROUP_X25519,
SSL_GROUP_SECP256R1,
SSL_GROUP_SECP384R1,
#if defined(BORINGSSL_ANDROID_SYSTEM)
SSL_GROUP_SECP521R1,
#endif
};
/* tls1_get_grouplist sets |*out_group_ids| and |*out_group_ids_len| to the
* list of allowed group IDs. If |get_peer_groups| is non-zero, return the
* peer's group list. Otherwise, return the preferred list. */
static void tls1_get_grouplist(SSL *ssl, int get_peer_groups,
const uint16_t **out_group_ids,
size_t *out_group_ids_len) {
if (get_peer_groups) {
/* Only clients send a supported group list, so this function is only
* called on the server. */
assert(ssl->server);
*out_group_ids = ssl->s3->tmp.peer_supported_group_list;
*out_group_ids_len = ssl->s3->tmp.peer_supported_group_list_len;
return;
}
*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 = sizeof(kDefaultGroups) / sizeof(kDefaultGroups[0]);
}
}
int tls1_get_shared_group(SSL *ssl, uint16_t *out_group_id) {
const uint16_t *groups, *peer_groups, *pref, *supp;
size_t groups_len, peer_groups_len, pref_len, supp_len, i, j;
/* Can't do anything on client side */
if (ssl->server == 0) {
return 0;
}
tls1_get_grouplist(ssl, 0 /* local groups */, &groups, &groups_len);
tls1_get_grouplist(ssl, 1 /* peer groups */, &peer_groups, &peer_groups_len);
if (peer_groups_len == 0) {
/* 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. */
return 0;
}
if (ssl->options & SSL_OP_CIPHER_SERVER_PREFERENCE) {
pref = groups;
pref_len = groups_len;
supp = peer_groups;
supp_len = peer_groups_len;
} else {
pref = peer_groups;
pref_len = peer_groups_len;
supp = groups;
supp_len = groups_len;
}
for (i = 0; i < pref_len; i++) {
for (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;
size_t i;
group_ids = OPENSSL_malloc(ncurves * sizeof(uint16_t));
if (group_ids == NULL) {
return 0;
}
for (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;
}
/* tls1_curve_params_from_ec_key sets |*out_group_id| and |*out_comp_id| to the
* TLS group ID and point format, respectively, for |ec|. It returns one on
* success and zero on failure. */
static int tls1_curve_params_from_ec_key(uint16_t *out_group_id,
uint8_t *out_comp_id, EC_KEY *ec) {
int nid;
uint16_t id;
const EC_GROUP *grp;
if (ec == NULL) {
return 0;
}
grp = EC_KEY_get0_group(ec);
if (grp == NULL) {
return 0;
}
/* Determine group ID */
nid = EC_GROUP_get_curve_name(grp);
if (!ssl_nid_to_group_id(&id, nid)) {
return 0;
}
/* Set the named group ID. Arbitrary explicit groups are not supported. */
*out_group_id = id;
if (out_comp_id) {
if (EC_KEY_get0_public_key(ec) == NULL) {
return 0;
}
if (EC_KEY_get_conv_form(ec) == POINT_CONVERSION_COMPRESSED) {
*out_comp_id = TLSEXT_ECPOINTFORMAT_ansiX962_compressed_prime;
} else {
*out_comp_id = TLSEXT_ECPOINTFORMAT_uncompressed;
}
}
return 1;
}
/* tls1_check_group_id returns one if |group_id| is consistent with both our
* and the peer's group preferences. Note: if called as the client, only our
* preferences are checked; the peer (the server) does not send preferences. */
int tls1_check_group_id(SSL *ssl, uint16_t group_id) {
const uint16_t *groups;
size_t groups_len, i, get_peer_groups;
/* Check against our list, then the peer's list. */
for (get_peer_groups = 0; get_peer_groups <= 1; get_peer_groups++) {
if (get_peer_groups && !ssl->server) {
/* Servers do not present a preference list so, if we are a client, only
* check our list. */
continue;
}
tls1_get_grouplist(ssl, get_peer_groups, &groups, &groups_len);
if (get_peer_groups && groups_len == 0) {
/* 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. */
continue;
}
for (i = 0; i < groups_len; i++) {
if (groups[i] == group_id) {
break;
}
}
if (i == groups_len) {
return 0;
}
}
return 1;
}
int tls1_check_ec_cert(SSL *ssl, X509 *x) {
int ret = 0;
EVP_PKEY *pkey = X509_get_pubkey(x);
uint16_t group_id;
uint8_t comp_id;
if (!pkey) {
goto done;
}
EC_KEY *ec_key = EVP_PKEY_get0_EC_KEY(pkey);
if (ec_key == NULL ||
!tls1_curve_params_from_ec_key(&group_id, &comp_id, ec_key) ||
!tls1_check_group_id(ssl, group_id) ||
comp_id != TLSEXT_ECPOINTFORMAT_uncompressed) {
goto done;
}
ret = 1;
done:
EVP_PKEY_free(pkey);
return ret;
}
/* List of supported signature algorithms and hashes. Should make this
* customisable at some point, for now include everything we support. */
#define tlsext_sigalg_rsa(md) md, TLSEXT_signature_rsa,
#define tlsext_sigalg_ecdsa(md) md, TLSEXT_signature_ecdsa,
#define tlsext_sigalg(md) tlsext_sigalg_rsa(md) tlsext_sigalg_ecdsa(md)
static const uint8_t tls12_sigalgs[] = {
tlsext_sigalg(TLSEXT_hash_sha512)
tlsext_sigalg(TLSEXT_hash_sha384)
tlsext_sigalg(TLSEXT_hash_sha256)
tlsext_sigalg(TLSEXT_hash_sha1)
};
size_t tls12_get_psigalgs(SSL *ssl, const uint8_t **psigs) {
*psigs = tls12_sigalgs;
return sizeof(tls12_sigalgs);
}
int tls12_check_peer_sigalg(SSL *ssl, const EVP_MD **out_md, int *out_alert,
uint8_t hash, uint8_t signature, EVP_PKEY *pkey) {
const uint8_t *sent_sigs;
size_t sent_sigslen, i;
int sigalg = tls12_get_sigid(pkey->type);
/* Should never happen */
if (sigalg == -1) {
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
*out_alert = SSL_AD_INTERNAL_ERROR;
return 0;
}
/* Check key type is consistent with signature */
if (sigalg != signature) {
OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_SIGNATURE_TYPE);
*out_alert = SSL_AD_ILLEGAL_PARAMETER;
return 0;
}
/* Check signature matches a type we sent */
sent_sigslen = tls12_get_psigalgs(ssl, &sent_sigs);
for (i = 0; i < sent_sigslen; i += 2, sent_sigs += 2) {
if (hash == sent_sigs[0] && signature == sent_sigs[1]) {
break;
}
}
if (i == sent_sigslen) {
OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_SIGNATURE_TYPE);
*out_alert = SSL_AD_ILLEGAL_PARAMETER;
return 0;
}
*out_md = tls12_get_hash(hash);
if (*out_md == NULL) {
OPENSSL_PUT_ERROR(SSL, SSL_R_UNKNOWN_DIGEST);
*out_alert = SSL_AD_ILLEGAL_PARAMETER;
return 0;
}
return 1;
}
/* Get a mask of disabled algorithms: an algorithm is disabled if it isn't
* supported or doesn't appear in supported signature algorithms. Unlike
* ssl_cipher_get_disabled this applies to a specific session and not global
* settings. */
void ssl_set_client_disabled(SSL *ssl) {
CERT *c = ssl->cert;
const uint8_t *sigalgs;
size_t i, sigalgslen;
int have_rsa = 0, have_ecdsa = 0;
c->mask_a = 0;
c->mask_k = 0;
/* Now go through all signature algorithms seeing if we support any for RSA,
* DSA, ECDSA. Do this for all versions not just TLS 1.2. */
sigalgslen = tls12_get_psigalgs(ssl, &sigalgs);
for (i = 0; i < sigalgslen; i += 2, sigalgs += 2) {
switch (sigalgs[1]) {
case TLSEXT_signature_rsa:
have_rsa = 1;
break;
case TLSEXT_signature_ecdsa:
have_ecdsa = 1;
break;
}
}
/* Disable auth if we don't include any appropriate signature algorithms. */
if (!have_rsa) {
c->mask_a |= SSL_aRSA;
}
if (!have_ecdsa) {
c->mask_a |= SSL_aECDSA;
}
/* with PSK there must be client callback set */
if (!ssl->psk_client_callback) {
c->mask_a |= SSL_aPSK;
c->mask_k |= SSL_kPSK;
}
}
/* tls_extension represents a TLS extension that is handled internally. The
* |init| function is called for each handshake, before any other functions of
* the extension. Then the add and parse callbacks are called as needed.
*
* The parse callbacks receive a |CBS| that contains the contents of the
* extension (i.e. not including the type and length bytes). If an extension is
* not received then the parse callbacks will be called with a NULL CBS so that
* they can do any processing needed to handle the absence of an extension.
*
* The add callbacks receive a |CBB| to which the extension can be appended but
* the function is responsible for appending the type and length bytes too.
*
* All callbacks return one for success and zero for error. If a parse function
* returns zero then a fatal alert with value |*out_alert| will be sent. If
* |*out_alert| isn't set, then a |decode_error| alert will be sent. */
struct tls_extension {
uint16_t value;
void (*init)(SSL *ssl);
int (*add_clienthello)(SSL *ssl, CBB *out);
int (*parse_serverhello)(SSL *ssl, uint8_t *out_alert, CBS *contents);
int (*parse_clienthello)(SSL *ssl, uint8_t *out_alert, CBS *contents);
int (*add_serverhello)(SSL *ssl, CBB *out);
};
/* Server name indication (SNI).
*
* https://tools.ietf.org/html/rfc6066#section-3. */
static void ext_sni_init(SSL *ssl) {
ssl->s3->tmp.should_ack_sni = 0;
}
static int ext_sni_add_clienthello(SSL *ssl, CBB *out) {
if (ssl->tlsext_hostname == NULL) {
return 1;
}
CBB contents, server_name_list, name;
if (!CBB_add_u16(out, TLSEXT_TYPE_server_name) ||
!CBB_add_u16_length_prefixed(out, &contents) ||
!CBB_add_u16_length_prefixed(&contents, &server_name_list) ||
!CBB_add_u8(&server_name_list, TLSEXT_NAMETYPE_host_name) ||
!CBB_add_u16_length_prefixed(&server_name_list, &name) ||
!CBB_add_bytes(&name, (const uint8_t *)ssl->tlsext_hostname,
strlen(ssl->tlsext_hostname)) ||
!CBB_flush(out)) {
return 0;
}
return 1;
}
static int ext_sni_parse_serverhello(SSL *ssl, uint8_t *out_alert,
CBS *contents) {
if (contents == NULL) {
return 1;
}
if (CBS_len(contents) != 0) {
return 0;
}
assert(ssl->tlsext_hostname != NULL);
if (!ssl->hit) {
assert(ssl->session->tlsext_hostname == NULL);
ssl->session->tlsext_hostname = BUF_strdup(ssl->tlsext_hostname);
if (!ssl->session->tlsext_hostname) {
*out_alert = SSL_AD_INTERNAL_ERROR;
return 0;
}
}
return 1;
}
static int ext_sni_parse_clienthello(SSL *ssl, uint8_t *out_alert,
CBS *contents) {
if (contents == NULL) {
return 1;
}
CBS server_name_list, host_name;
uint8_t name_type;
if (!CBS_get_u16_length_prefixed(contents, &server_name_list) ||
!CBS_get_u8(&server_name_list, &name_type) ||
/* Although the server_name extension was intended to be extensible to
* new name types and multiple names, OpenSSL 1.0.x had a bug which meant
* different name types will cause an error. Further, RFC 4366 originally
* defined syntax inextensibly. RFC 6066 corrected this mistake, but
* adding new name types is no longer feasible.
*
* Act as if the extensibility does not exist to simplify parsing. */
!CBS_get_u16_length_prefixed(&server_name_list, &host_name) ||
CBS_len(&server_name_list) != 0 ||
CBS_len(contents) != 0) {
return 0;
}
if (name_type != TLSEXT_NAMETYPE_host_name ||
CBS_len(&host_name) == 0 ||
CBS_len(&host_name) > TLSEXT_MAXLEN_host_name ||
CBS_contains_zero_byte(&host_name)) {
*out_alert = SSL_AD_UNRECOGNIZED_NAME;
return 0;
}
/* TODO(davidben): SNI should be resolved before resumption. We have the
* early callback as a replacement, but we should fix the current callback
* and avoid the need for |SSL_CTX_set_session_id_context|. */
if (!ssl->hit) {
assert(ssl->session->tlsext_hostname == NULL);
/* Copy the hostname as a string. */
if (!CBS_strdup(&host_name, &ssl->session->tlsext_hostname)) {
*out_alert = SSL_AD_INTERNAL_ERROR;
return 0;
}
ssl->s3->tmp.should_ack_sni = 1;
}
return 1;
}
static int ext_sni_add_serverhello(SSL *ssl, CBB *out) {
if (ssl->hit ||
!ssl->s3->tmp.should_ack_sni ||
ssl->session->tlsext_hostname == NULL) {
return 1;
}
if (!CBB_add_u16(out, TLSEXT_TYPE_server_name) ||
!CBB_add_u16(out, 0 /* length */)) {
return 0;
}
return 1;
}
/* Renegotiation indication.
*
* https://tools.ietf.org/html/rfc5746 */
static int ext_ri_add_clienthello(SSL *ssl, CBB *out) {
CBB contents, prev_finished;
if (!CBB_add_u16(out, TLSEXT_TYPE_renegotiate) ||
!CBB_add_u16_length_prefixed(out, &contents) ||
!CBB_add_u8_length_prefixed(&contents, &prev_finished) ||
!CBB_add_bytes(&prev_finished, ssl->s3->previous_client_finished,
ssl->s3->previous_client_finished_len) ||
!CBB_flush(out)) {
return 0;
}
return 1;
}
static int ext_ri_parse_serverhello(SSL *ssl, uint8_t *out_alert,
CBS *contents) {
/* 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);
/* Parse out the extension contents. */
CBS renegotiated_connection;
if (!CBS_get_u8_length_prefixed(contents, &renegotiated_connection) ||
CBS_len(contents) != 0) {
OPENSSL_PUT_ERROR(SSL, SSL_R_RENEGOTIATION_ENCODING_ERR);
*out_alert = SSL_AD_ILLEGAL_PARAMETER;
return 0;
}
/* Check that the extension matches. */
if (CBS_len(&renegotiated_connection) != expected_len) {
OPENSSL_PUT_ERROR(SSL, SSL_R_RENEGOTIATION_MISMATCH);
*out_alert = SSL_AD_HANDSHAKE_FAILURE;
return 0;
}
const uint8_t *d = CBS_data(&renegotiated_connection);
if (CRYPTO_memcmp(d, ssl->s3->previous_client_finished,
ssl->s3->previous_client_finished_len)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_RENEGOTIATION_MISMATCH);
*out_alert = SSL_AD_HANDSHAKE_FAILURE;
return 0;
}
d += ssl->s3->previous_client_finished_len;
if (CRYPTO_memcmp(d, ssl->s3->previous_server_finished,
ssl->s3->previous_server_finished_len)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_RENEGOTIATION_MISMATCH);
*out_alert = SSL_AD_ILLEGAL_PARAMETER;
return 0;
}
ssl->s3->send_connection_binding = 1;
return 1;
}
static int ext_ri_parse_clienthello(SSL *ssl, uint8_t *out_alert,
CBS *contents) {
/* Renegotiation isn't supported as a server so this function should never be
* called after the initial handshake. */
assert(!ssl->s3->initial_handshake_complete);
CBS fake_contents;
static const uint8_t kFakeExtension[] = {0};
if (contents == NULL) {
if (ssl->s3->send_connection_binding) {
/* The renegotiation SCSV was received so pretend that we received a
* renegotiation extension. */
CBS_init(&fake_contents, kFakeExtension, sizeof(kFakeExtension));
contents = &fake_contents;
/* We require that the renegotiation extension is at index zero of
* kExtensions. */
ssl->s3->tmp.extensions.received |= (1u << 0);
} else {
return 1;
}
}
CBS renegotiated_connection;
if (!CBS_get_u8_length_prefixed(contents, &renegotiated_connection) ||
CBS_len(contents) != 0) {
OPENSSL_PUT_ERROR(SSL, SSL_R_RENEGOTIATION_ENCODING_ERR);
return 0;
}
/* Check that the extension matches */
if (!CBS_mem_equal(&renegotiated_connection,
ssl->s3->previous_client_finished,
ssl->s3->previous_client_finished_len)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_RENEGOTIATION_MISMATCH);
*out_alert = SSL_AD_HANDSHAKE_FAILURE;
return 0;
}
ssl->s3->send_connection_binding = 1;
return 1;
}
static int ext_ri_add_serverhello(SSL *ssl, CBB *out) {
CBB contents, prev_finished;
if (!CBB_add_u16(out, TLSEXT_TYPE_renegotiate) ||
!CBB_add_u16_length_prefixed(out, &contents) ||
!CBB_add_u8_length_prefixed(&contents, &prev_finished) ||
!CBB_add_bytes(&prev_finished, ssl->s3->previous_client_finished,
ssl->s3->previous_client_finished_len) ||
!CBB_add_bytes(&prev_finished, ssl->s3->previous_server_finished,
ssl->s3->previous_server_finished_len) ||
!CBB_flush(out)) {
return 0;
}
return 1;
}
/* Extended Master Secret.
*
* https://tools.ietf.org/html/rfc7627 */
static void ext_ems_init(SSL *ssl) {
ssl->s3->tmp.extended_master_secret = 0;
}
static int ext_ems_add_clienthello(SSL *ssl, CBB *out) {
if (ssl->version == SSL3_VERSION) {
return 1;
}
if (!CBB_add_u16(out, TLSEXT_TYPE_extended_master_secret) ||
!CBB_add_u16(out, 0 /* length */)) {
return 0;
}
return 1;
}
static int ext_ems_parse_serverhello(SSL *ssl, uint8_t *out_alert,
CBS *contents) {
if (contents == NULL) {
return 1;
}
if (ssl->version == SSL3_VERSION || CBS_len(contents) != 0) {
return 0;
}
ssl->s3->tmp.extended_master_secret = 1;
return 1;
}
static int ext_ems_parse_clienthello(SSL *ssl, uint8_t *out_alert,
CBS *contents) {
if (ssl->version == SSL3_VERSION || contents == NULL) {
return 1;
}
if (CBS_len(contents) != 0) {
return 0;
}
ssl->s3->tmp.extended_master_secret = 1;
return 1;
}
static int ext_ems_add_serverhello(SSL *ssl, CBB *out) {
if (!ssl->s3->tmp.extended_master_secret) {
return 1;
}
if (!CBB_add_u16(out, TLSEXT_TYPE_extended_master_secret) ||
!CBB_add_u16(out, 0 /* length */)) {
return 0;
}
return 1;
}
/* Session tickets.
*
* https://tools.ietf.org/html/rfc5077 */
static int ext_ticket_add_clienthello(SSL *ssl, CBB *out) {
if (SSL_get_options(ssl) & SSL_OP_NO_TICKET) {
return 1;
}
const uint8_t *ticket_data = NULL;
int ticket_len = 0;
/* Renegotiation does not participate in session resumption. However, still
* advertise the extension to avoid potentially breaking servers which carry
* over the state from the previous handshake, such as OpenSSL servers
* without upstream's 3c3f0259238594d77264a78944d409f2127642c4. */
if (!ssl->s3->initial_handshake_complete &&
ssl->session != NULL &&
ssl->session->tlsext_tick != NULL) {
ticket_data = ssl->session->tlsext_tick;
ticket_len = ssl->session->tlsext_ticklen;
}
CBB ticket;
if (!CBB_add_u16(out, TLSEXT_TYPE_session_ticket) ||
!CBB_add_u16_length_prefixed(out, &ticket) ||
!CBB_add_bytes(&ticket, ticket_data, ticket_len) ||
!CBB_flush(out)) {
return 0;
}
return 1;
}
static int ext_ticket_parse_serverhello(SSL *ssl, uint8_t *out_alert,
CBS *contents) {
ssl->tlsext_ticket_expected = 0;
if (contents == NULL) {
return 1;
}
/* If |SSL_OP_NO_TICKET| is set then no extension will have been sent and
* this function should never be called, even if the server tries to send the
* extension. */
assert((SSL_get_options(ssl) & SSL_OP_NO_TICKET) == 0);
if (CBS_len(contents) != 0) {
return 0;
}
ssl->tlsext_ticket_expected = 1;
return 1;
}
static int ext_ticket_parse_clienthello(SSL *ssl, uint8_t *out_alert,
CBS *contents) {
/* This function isn't used because the ticket extension from the client is
* handled in ssl_session.c. */
return 1;
}
static int ext_ticket_add_serverhello(SSL *ssl, CBB *out) {
if (!ssl->tlsext_ticket_expected) {
return 1;
}
/* If |SSL_OP_NO_TICKET| is set, |tlsext_ticket_expected| should never be
* true. */
assert((SSL_get_options(ssl) & SSL_OP_NO_TICKET) == 0);
if (!CBB_add_u16(out, TLSEXT_TYPE_session_ticket) ||
!CBB_add_u16(out, 0 /* length */)) {
return 0;
}
return 1;
}
/* Signature Algorithms.
*
* https://tools.ietf.org/html/rfc5246#section-7.4.1.4.1 */
static int ext_sigalgs_add_clienthello(SSL *ssl, CBB *out) {
if (ssl3_version_from_wire(ssl, ssl->client_version) < TLS1_2_VERSION) {
return 1;
}
const uint8_t *sigalgs_data;
const size_t sigalgs_len = tls12_get_psigalgs(ssl, &sigalgs_data);
CBB contents, sigalgs;
if (!CBB_add_u16(out, TLSEXT_TYPE_signature_algorithms) ||
!CBB_add_u16_length_prefixed(out, &contents) ||
!CBB_add_u16_length_prefixed(&contents, &sigalgs) ||
!CBB_add_bytes(&sigalgs, sigalgs_data, sigalgs_len) ||
!CBB_flush(out)) {
return 0;
}
return 1;
}
static int ext_sigalgs_parse_serverhello(SSL *ssl, uint8_t *out_alert,
CBS *contents) {
if (contents != NULL) {
/* Servers MUST NOT send this extension. */
*out_alert = SSL_AD_UNSUPPORTED_EXTENSION;
OPENSSL_PUT_ERROR(SSL, SSL_R_SIGNATURE_ALGORITHMS_EXTENSION_SENT_BY_SERVER);
return 0;
}
return 1;
}
static int ext_sigalgs_parse_clienthello(SSL *ssl, uint8_t *out_alert,
CBS *contents) {
OPENSSL_free(ssl->cert->peer_sigalgs);
ssl->cert->peer_sigalgs = NULL;
ssl->cert->peer_sigalgslen = 0;
if (contents == NULL) {
return 1;
}
CBS supported_signature_algorithms;
if (!CBS_get_u16_length_prefixed(contents, &supported_signature_algorithms) ||
CBS_len(contents) != 0 ||
CBS_len(&supported_signature_algorithms) == 0 ||
!tls1_parse_peer_sigalgs(ssl, &supported_signature_algorithms)) {
return 0;
}
return 1;
}
static int ext_sigalgs_add_serverhello(SSL *ssl, CBB *out) {
/* Servers MUST NOT send this extension. */
return 1;
}
/* OCSP Stapling.
*
* https://tools.ietf.org/html/rfc6066#section-8 */
static void ext_ocsp_init(SSL *ssl) {
ssl->s3->tmp.certificate_status_expected = 0;
ssl->tlsext_status_type = -1;
}
static int ext_ocsp_add_clienthello(SSL *ssl, CBB *out) {
if (!ssl->ocsp_stapling_enabled) {
return 1;
}
CBB contents;
if (!CBB_add_u16(out, TLSEXT_TYPE_status_request) ||
!CBB_add_u16_length_prefixed(out, &contents) ||
!CBB_add_u8(&contents, TLSEXT_STATUSTYPE_ocsp) ||
!CBB_add_u16(&contents, 0 /* empty responder ID list */) ||
!CBB_add_u16(&contents, 0 /* empty request extensions */) ||
!CBB_flush(out)) {
return 0;
}
ssl->tlsext_status_type = TLSEXT_STATUSTYPE_ocsp;
return 1;
}
static int ext_ocsp_parse_serverhello(SSL *ssl, uint8_t *out_alert,
CBS *contents) {
if (contents == NULL) {
return 1;
}
if (CBS_len(contents) != 0) {
return 0;
}
ssl->s3->tmp.certificate_status_expected = 1;
return 1;
}
static int ext_ocsp_parse_clienthello(SSL *ssl, uint8_t *out_alert,
CBS *contents) {
if (contents == NULL) {
return 1;
}
uint8_t status_type;
if (!CBS_get_u8(contents, &status_type)) {
return 0;
}
/* We cannot decide whether OCSP stapling will occur yet because the correct
* SSL_CTX might not have been selected. */
ssl->s3->tmp.ocsp_stapling_requested = status_type == TLSEXT_STATUSTYPE_ocsp;
return 1;
}
static int ext_ocsp_add_serverhello(SSL *ssl, CBB *out) {
/* The extension shouldn't be sent when resuming sessions. */
if (ssl->hit ||
!ssl->s3->tmp.ocsp_stapling_requested ||
ssl->ctx->ocsp_response_length == 0) {
return 1;
}
ssl->s3->tmp.certificate_status_expected = 1;
return CBB_add_u16(out, TLSEXT_TYPE_status_request) &&
CBB_add_u16(out, 0 /* length */);
}
/* Next protocol negotiation.
*
* https://htmlpreview.github.io/?https://github.com/agl/technotes/blob/master/nextprotoneg.html */
static void ext_npn_init(SSL *ssl) {
ssl->s3->next_proto_neg_seen = 0;
}
static int ext_npn_add_clienthello(SSL *ssl, CBB *out) {
if (ssl->s3->initial_handshake_complete ||
ssl->ctx->next_proto_select_cb == NULL ||
(ssl->options & SSL_OP_DISABLE_NPN) ||
SSL_IS_DTLS(ssl)) {
return 1;
}
if (!CBB_add_u16(out, TLSEXT_TYPE_next_proto_neg) ||
!CBB_add_u16(out, 0 /* length */)) {
return 0;
}
return 1;
}
static int ext_npn_parse_serverhello(SSL *ssl, uint8_t *out_alert,
CBS *contents) {
if (contents == NULL) {
return 1;
}
/* If any of these are false then we should never have sent the NPN
* extension in the ClientHello and thus this function should never have been
* called. */
assert(!ssl->s3->initial_handshake_complete);
assert(!SSL_IS_DTLS(ssl));
assert(ssl->ctx->next_proto_select_cb != NULL);
assert(!(ssl->options & SSL_OP_DISABLE_NPN));
if (ssl->s3->alpn_selected != NULL) {
/* NPN and ALPN may not be negotiated in the same connection. */
*out_alert = SSL_AD_ILLEGAL_PARAMETER;
OPENSSL_PUT_ERROR(SSL, SSL_R_NEGOTIATED_BOTH_NPN_AND_ALPN);
return 0;
}
const uint8_t *const orig_contents = CBS_data(contents);
const size_t orig_len = CBS_len(contents);
while (CBS_len(contents) != 0) {
CBS proto;
if (!CBS_get_u8_length_prefixed(contents, &proto) ||
CBS_len(&proto) == 0) {
return 0;
}
}
uint8_t *selected;
uint8_t selected_len;
if (ssl->ctx->next_proto_select_cb(
ssl, &selected, &selected_len, orig_contents, orig_len,
ssl->ctx->next_proto_select_cb_arg) != SSL_TLSEXT_ERR_OK) {
*out_alert = SSL_AD_INTERNAL_ERROR;
return 0;
}
OPENSSL_free(ssl->s3->next_proto_negotiated);
ssl->s3->next_proto_negotiated = BUF_memdup(selected, selected_len);
if (ssl->s3->next_proto_negotiated == NULL) {
*out_alert = SSL_AD_INTERNAL_ERROR;
return 0;
}
ssl->s3->next_proto_negotiated_len = selected_len;
ssl->s3->next_proto_neg_seen = 1;
return 1;
}
static int ext_npn_parse_clienthello(SSL *ssl, uint8_t *out_alert,
CBS *contents) {
if (contents != NULL && CBS_len(contents) != 0) {
return 0;
}
if (contents == NULL ||
ssl->s3->initial_handshake_complete ||
/* If the ALPN extension is seen before NPN, ignore it. (If ALPN is seen
* afterwards, parsing the ALPN extension will clear
* |next_proto_neg_seen|. */
ssl->s3->alpn_selected != NULL ||
ssl->ctx->next_protos_advertised_cb == NULL ||
SSL_IS_DTLS(ssl)) {
return 1;
}
ssl->s3->next_proto_neg_seen = 1;
return 1;
}
static int ext_npn_add_serverhello(SSL *ssl, CBB *out) {
/* |next_proto_neg_seen| might have been cleared when an ALPN extension was
* parsed. */
if (!ssl->s3->next_proto_neg_seen) {
return 1;
}
const uint8_t *npa;
unsigned npa_len;
if (ssl->ctx->next_protos_advertised_cb(
ssl, &npa, &npa_len, ssl->ctx->next_protos_advertised_cb_arg) !=
SSL_TLSEXT_ERR_OK) {
ssl->s3->next_proto_neg_seen = 0;
return 1;
}
CBB contents;
if (!CBB_add_u16(out, TLSEXT_TYPE_next_proto_neg) ||
!CBB_add_u16_length_prefixed(out, &contents) ||
!CBB_add_bytes(&contents, npa, npa_len) ||
!CBB_flush(out)) {
return 0;
}
return 1;
}
/* Signed certificate timestamps.
*
* https://tools.ietf.org/html/rfc6962#section-3.3.1 */
static int ext_sct_add_clienthello(SSL *ssl, CBB *out) {
if (!ssl->signed_cert_timestamps_enabled) {
return 1;
}
if (!CBB_add_u16(out, TLSEXT_TYPE_certificate_timestamp) ||
!CBB_add_u16(out, 0 /* length */)) {
return 0;
}
return 1;
}
static int ext_sct_parse_serverhello(SSL *ssl, uint8_t *out_alert,
CBS *contents) {
if (contents == NULL) {
return 1;
}
/* If this is false then we should never have sent the SCT extension in the
* ClientHello and thus this function should never have been called. */
assert(ssl->signed_cert_timestamps_enabled);
if (CBS_len(contents) == 0) {
*out_alert = SSL_AD_DECODE_ERROR;
return 0;
}
/* Session resumption uses the original session information. */
if (!ssl->hit &&
!CBS_stow(contents, &ssl->session->tlsext_signed_cert_timestamp_list,
&ssl->session->tlsext_signed_cert_timestamp_list_length)) {
*out_alert = SSL_AD_INTERNAL_ERROR;
return 0;
}
return 1;
}
static int ext_sct_parse_clienthello(SSL *ssl, uint8_t *out_alert,
CBS *contents) {
return contents == NULL || CBS_len(contents) == 0;
}
static int ext_sct_add_serverhello(SSL *ssl, CBB *out) {
/* The extension shouldn't be sent when resuming sessions. */
if (ssl->hit ||
ssl->ctx->signed_cert_timestamp_list_length == 0) {
return 1;
}
CBB contents;
return CBB_add_u16(out, TLSEXT_TYPE_certificate_timestamp) &&
CBB_add_u16_length_prefixed(out, &contents) &&
CBB_add_bytes(&contents, ssl->ctx->signed_cert_timestamp_list,
ssl->ctx->signed_cert_timestamp_list_length) &&
CBB_flush(out);
}
/* Application-level Protocol Negotiation.
*
* https://tools.ietf.org/html/rfc7301 */
static void ext_alpn_init(SSL *ssl) {
OPENSSL_free(ssl->s3->alpn_selected);
ssl->s3->alpn_selected = NULL;
}
static int ext_alpn_add_clienthello(SSL *ssl, CBB *out) {
if (ssl->alpn_client_proto_list == NULL ||
ssl->s3->initial_handshake_complete) {
return 1;
}
CBB contents, proto_list;
if (!CBB_add_u16(out, TLSEXT_TYPE_application_layer_protocol_negotiation) ||
!CBB_add_u16_length_prefixed(out, &contents) ||
!CBB_add_u16_length_prefixed(&contents, &proto_list) ||
!CBB_add_bytes(&proto_list, ssl->alpn_client_proto_list,
ssl->alpn_client_proto_list_len) ||
!CBB_flush(out)) {
return 0;
}
return 1;
}
static int ext_alpn_parse_serverhello(SSL *ssl, uint8_t *out_alert,
CBS *contents) {
if (contents == NULL) {
return 1;
}
assert(!ssl->s3->initial_handshake_complete);
assert(ssl->alpn_client_proto_list != NULL);
if (ssl->s3->next_proto_neg_seen) {
/* NPN and ALPN may not be negotiated in the same connection. */
*out_alert = SSL_AD_ILLEGAL_PARAMETER;
OPENSSL_PUT_ERROR(SSL, SSL_R_NEGOTIATED_BOTH_NPN_AND_ALPN);
return 0;
}
/* The extension data consists of a ProtocolNameList which must have
* exactly one ProtocolName. Each of these is length-prefixed. */
CBS protocol_name_list, protocol_name;
if (!CBS_get_u16_length_prefixed(contents, &protocol_name_list) ||
CBS_len(contents) != 0 ||
!CBS_get_u8_length_prefixed(&protocol_name_list, &protocol_name) ||
/* Empty protocol names are forbidden. */
CBS_len(&protocol_name) == 0 ||
CBS_len(&protocol_name_list) != 0) {
return 0;
}
if (!CBS_stow(&protocol_name, &ssl->s3->alpn_selected,
&ssl->s3->alpn_selected_len)) {
*out_alert = SSL_AD_INTERNAL_ERROR;
return 0;
}
return 1;
}
static int ext_alpn_parse_clienthello(SSL *ssl, uint8_t *out_alert,
CBS *contents) {
if (contents == NULL) {
return 1;
}
if (ssl->ctx->alpn_select_cb == NULL ||
ssl->s3->initial_handshake_complete) {
return 1;
}
/* ALPN takes precedence over NPN. */
ssl->s3->next_proto_neg_seen = 0;
CBS protocol_name_list;
if (!CBS_get_u16_length_prefixed(contents, &protocol_name_list) ||
CBS_len(contents) != 0 ||
CBS_len(&protocol_name_list) < 2) {
return 0;
}
/* Validate the protocol list. */
CBS protocol_name_list_copy = protocol_name_list;
while (CBS_len(&protocol_name_list_copy) > 0) {
CBS protocol_name;
if (!CBS_get_u8_length_prefixed(&protocol_name_list_copy, &protocol_name) ||
/* Empty protocol names are forbidden. */
CBS_len(&protocol_name) == 0) {
return 0;
}
}
const uint8_t *selected;
uint8_t selected_len;
if (ssl->ctx->alpn_select_cb(
ssl, &selected, &selected_len, CBS_data(&protocol_name_list),
CBS_len(&protocol_name_list),
ssl->ctx->alpn_select_cb_arg) == SSL_TLSEXT_ERR_OK) {
OPENSSL_free(ssl->s3->alpn_selected);
ssl->s3->alpn_selected = BUF_memdup(selected, selected_len);
if (ssl->s3->alpn_selected == NULL) {
*out_alert = SSL_AD_INTERNAL_ERROR;
return 0;
}
ssl->s3->alpn_selected_len = selected_len;
}
return 1;
}
static int ext_alpn_add_serverhello(SSL *ssl, CBB *out) {
if (ssl->s3->alpn_selected == NULL) {
return 1;
}
CBB contents, proto_list, proto;
if (!CBB_add_u16(out, TLSEXT_TYPE_application_layer_protocol_negotiation) ||
!CBB_add_u16_length_prefixed(out, &contents) ||
!CBB_add_u16_length_prefixed(&contents, &proto_list) ||
!CBB_add_u8_length_prefixed(&proto_list, &proto) ||
!CBB_add_bytes(&proto, ssl->s3->alpn_selected,
ssl->s3->alpn_selected_len) ||
!CBB_flush(out)) {
return 0;
}
return 1;
}
/* Channel ID.
*
* https://tools.ietf.org/html/draft-balfanz-tls-channelid-01 */
static void ext_channel_id_init(SSL *ssl) {
ssl->s3->tlsext_channel_id_valid = 0;
}
static int ext_channel_id_add_clienthello(SSL *ssl, CBB *out) {
if (!ssl->tlsext_channel_id_enabled ||
SSL_IS_DTLS(ssl)) {
return 1;
}
if (!CBB_add_u16(out, TLSEXT_TYPE_channel_id) ||
!CBB_add_u16(out, 0 /* length */)) {
return 0;
}
return 1;
}
static int ext_channel_id_parse_serverhello(SSL *ssl, uint8_t *out_alert,
CBS *contents) {
if (contents == NULL) {
return 1;
}
assert(!SSL_IS_DTLS(ssl));
assert(ssl->tlsext_channel_id_enabled);
if (CBS_len(contents) != 0) {
return 0;
}
ssl->s3->tlsext_channel_id_valid = 1;
return 1;
}
static int ext_channel_id_parse_clienthello(SSL *ssl, uint8_t *out_alert,
CBS *contents) {
if (contents == NULL ||
!ssl->tlsext_channel_id_enabled ||
SSL_IS_DTLS(ssl)) {
return 1;
}
if (CBS_len(contents) != 0) {
return 0;
}
ssl->s3->tlsext_channel_id_valid = 1;
return 1;
}
static int ext_channel_id_add_serverhello(SSL *ssl, CBB *out) {
if (!ssl->s3->tlsext_channel_id_valid) {
return 1;
}
if (!CBB_add_u16(out, TLSEXT_TYPE_channel_id) ||
!CBB_add_u16(out, 0 /* length */)) {
return 0;
}
return 1;
}
/* Secure Real-time Transport Protocol (SRTP) extension.
*
* https://tools.ietf.org/html/rfc5764 */
static void ext_srtp_init(SSL *ssl) {
ssl->srtp_profile = NULL;
}
static int ext_srtp_add_clienthello(SSL *ssl, CBB *out) {
STACK_OF(SRTP_PROTECTION_PROFILE) *profiles = SSL_get_srtp_profiles(ssl);
if (profiles == NULL) {
return 1;
}
const size_t num_profiles = sk_SRTP_PROTECTION_PROFILE_num(profiles);
if (num_profiles == 0) {
return 1;
}
CBB contents, profile_ids;
if (!CBB_add_u16(out, TLSEXT_TYPE_srtp) ||
!CBB_add_u16_length_prefixed(out, &contents) ||
!CBB_add_u16_length_prefixed(&contents, &profile_ids)) {
return 0;
}
size_t i;
for (i = 0; i < num_profiles; i++) {
if (!CBB_add_u16(&profile_ids,
sk_SRTP_PROTECTION_PROFILE_value(profiles, i)->id)) {
return 0;
}
}
if (!CBB_add_u8(&contents, 0 /* empty use_mki value */) ||
!CBB_flush(out)) {
return 0;
}
return 1;
}
static int ext_srtp_parse_serverhello(SSL *ssl, uint8_t *out_alert,
CBS *contents) {
if (contents == NULL) {
return 1;
}
/* The extension consists of a u16-prefixed profile ID list containing a
* single uint16_t profile ID, then followed by a u8-prefixed srtp_mki field.
*
* See https://tools.ietf.org/html/rfc5764#section-4.1.1 */
CBS profile_ids, srtp_mki;
uint16_t profile_id;
if (!CBS_get_u16_length_prefixed(contents, &profile_ids) ||
!CBS_get_u16(&profile_ids, &profile_id) ||
CBS_len(&profile_ids) != 0 ||
!CBS_get_u8_length_prefixed(contents, &srtp_mki) ||
CBS_len(contents) != 0) {
OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
return 0;
}
if (CBS_len(&srtp_mki) != 0) {
/* Must be no MKI, since we never offer one. */
OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_SRTP_MKI_VALUE);
*out_alert = SSL_AD_ILLEGAL_PARAMETER;
return 0;
}
STACK_OF(SRTP_PROTECTION_PROFILE) *profiles = SSL_get_srtp_profiles(ssl);
/* Check to see if the server gave us something we support (and presumably
* offered). */
size_t i;
for (i = 0; i < sk_SRTP_PROTECTION_PROFILE_num(profiles); i++) {
const SRTP_PROTECTION_PROFILE *profile =
sk_SRTP_PROTECTION_PROFILE_value(profiles, i);
if (profile->id == profile_id) {
ssl->srtp_profile = profile;
return 1;
}
}
OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
*out_alert = SSL_AD_ILLEGAL_PARAMETER;
return 0;
}
static int ext_srtp_parse_clienthello(SSL *ssl, uint8_t *out_alert,
CBS *contents) {
if (contents == NULL) {
return 1;
}
CBS profile_ids, srtp_mki;
if (!CBS_get_u16_length_prefixed(contents, &profile_ids) ||
CBS_len(&profile_ids) < 2 ||
!CBS_get_u8_length_prefixed(contents, &srtp_mki) ||
CBS_len(contents) != 0) {
OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
return 0;
}
/* Discard the MKI value for now. */
const STACK_OF(SRTP_PROTECTION_PROFILE) *server_profiles =
SSL_get_srtp_profiles(ssl);
/* Pick the server's most preferred profile. */
size_t i;
for (i = 0; i < sk_SRTP_PROTECTION_PROFILE_num(server_profiles); i++) {
const SRTP_PROTECTION_PROFILE *server_profile =
sk_SRTP_PROTECTION_PROFILE_value(server_profiles, i);
CBS profile_ids_tmp;
CBS_init(&profile_ids_tmp, CBS_data(&profile_ids), CBS_len(&profile_ids));
while (CBS_len(&profile_ids_tmp) > 0) {
uint16_t profile_id;
if (!CBS_get_u16(&profile_ids_tmp, &profile_id)) {
return 0;
}
if (server_profile->id == profile_id) {
ssl->srtp_profile = server_profile;
return 1;
}
}
}
return 1;
}
static int ext_srtp_add_serverhello(SSL *ssl, CBB *out) {
if (ssl->srtp_profile == NULL) {
return 1;
}
CBB contents, profile_ids;
if (!CBB_add_u16(out, TLSEXT_TYPE_srtp) ||
!CBB_add_u16_length_prefixed(out, &contents) ||
!CBB_add_u16_length_prefixed(&contents, &profile_ids) ||
!CBB_add_u16(&profile_ids, ssl->srtp_profile->id) ||
!CBB_add_u8(&contents, 0 /* empty MKI */) ||
!CBB_flush(out)) {
return 0;
}
return 1;
}
/* EC point formats.
*
* https://tools.ietf.org/html/rfc4492#section-5.1.2 */
static int ssl_any_ec_cipher_suites_enabled(const SSL *ssl) {
if (ssl->version < TLS1_VERSION && !SSL_IS_DTLS(ssl)) {
return 0;
}
const STACK_OF(SSL_CIPHER) *cipher_stack = SSL_get_ciphers(ssl);
size_t i;
for (i = 0; i < sk_SSL_CIPHER_num(cipher_stack); i++) {
const SSL_CIPHER *cipher = sk_SSL_CIPHER_value(cipher_stack, i);
const uint32_t alg_k = cipher->algorithm_mkey;
const uint32_t alg_a = cipher->algorithm_auth;
if ((alg_k & SSL_kECDHE) || (alg_a & SSL_aECDSA)) {
return 1;
}
}
return 0;
}
static int ext_ec_point_add_extension(SSL *ssl, CBB *out) {
CBB contents, formats;
if (!CBB_add_u16(out, TLSEXT_TYPE_ec_point_formats) ||
!CBB_add_u16_length_prefixed(out, &contents) ||
!CBB_add_u8_length_prefixed(&contents, &formats) ||
!CBB_add_u8(&formats, TLSEXT_ECPOINTFORMAT_uncompressed) ||
!CBB_flush(out)) {
return 0;
}
return 1;
}
static int ext_ec_point_add_clienthello(SSL *ssl, CBB *out) {
if (!ssl_any_ec_cipher_suites_enabled(ssl)) {
return 1;
}
return ext_ec_point_add_extension(ssl, out);
}
static int ext_ec_point_parse_serverhello(SSL *ssl, uint8_t *out_alert,
CBS *contents) {
if (contents == NULL) {
return 1;
}
CBS ec_point_format_list;
if (!CBS_get_u8_length_prefixed(contents, &ec_point_format_list) ||
CBS_len(contents) != 0) {
return 0;
}
/* Per RFC 4492, section 5.1.2, implementations MUST support the uncompressed
* point format. */
if (memchr(CBS_data(&ec_point_format_list), TLSEXT_ECPOINTFORMAT_uncompressed,
CBS_len(&ec_point_format_list)) == NULL) {
*out_alert = SSL_AD_ILLEGAL_PARAMETER;
return 0;
}
return 1;
}
static int ext_ec_point_parse_clienthello(SSL *ssl, uint8_t *out_alert,
CBS *contents) {
return ext_ec_point_parse_serverhello(ssl, out_alert, contents);
}
static int ext_ec_point_add_serverhello(SSL *ssl, CBB *out) {
const uint32_t alg_k = ssl->s3->tmp.new_cipher->algorithm_mkey;
const uint32_t alg_a = ssl->s3->tmp.new_cipher->algorithm_auth;
const int using_ecc = (alg_k & SSL_kECDHE) || (alg_a & SSL_aECDSA);
if (!using_ecc) {
return 1;
}
return ext_ec_point_add_extension(ssl, out);
}
/* Negotiated Groups
*
* https://tools.ietf.org/html/rfc4492#section-5.1.2
* https://tools.ietf.org/html/draft-ietf-tls-tls13-12#section-6.3.2.2 */
static void ext_supported_groups_init(SSL *ssl) {
OPENSSL_free(ssl->s3->tmp.peer_supported_group_list);
ssl->s3->tmp.peer_supported_group_list = NULL;
ssl->s3->tmp.peer_supported_group_list_len = 0;
}
static int ext_supported_groups_add_clienthello(SSL *ssl, CBB *out) {
if (!ssl_any_ec_cipher_suites_enabled(ssl)) {
return 1;
}
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;
}
const uint16_t *groups;
size_t groups_len;
tls1_get_grouplist(ssl, 0, &groups, &groups_len);
size_t i;
for (i = 0; i < groups_len; i++) {
if (!CBB_add_u16(&groups_bytes, groups[i])) {
return 0;
}
}
return CBB_flush(out);
}
static int ext_supported_groups_parse_serverhello(SSL *ssl, uint8_t *out_alert,
CBS *contents) {
/* This extension is not expected to be echoed by servers and is ignored. */
return 1;
}
static int ext_supported_groups_parse_clienthello(SSL *ssl, uint8_t *out_alert,
CBS *contents) {
if (contents == NULL) {
return 1;
}
CBS supported_group_list;
if (!CBS_get_u16_length_prefixed(contents, &supported_group_list) ||
CBS_len(&supported_group_list) == 0 ||
(CBS_len(&supported_group_list) & 1) != 0 ||
CBS_len(contents) != 0) {
return 0;
}
ssl->s3->tmp.peer_supported_group_list = OPENSSL_malloc(
CBS_len(&supported_group_list));
if (ssl->s3->tmp.peer_supported_group_list == NULL) {
*out_alert = SSL_AD_INTERNAL_ERROR;
return 0;
}
const size_t num_groups = CBS_len(&supported_group_list) / 2;
size_t i;
for (i = 0; i < num_groups; i++) {
if (!CBS_get_u16(&supported_group_list,
&ssl->s3->tmp.peer_supported_group_list[i])) {
goto err;
}
}
assert(CBS_len(&supported_group_list) == 0);
ssl->s3->tmp.peer_supported_group_list_len = num_groups;
return 1;
err:
OPENSSL_free(ssl->s3->tmp.peer_supported_group_list);
ssl->s3->tmp.peer_supported_group_list = NULL;
*out_alert = SSL_AD_INTERNAL_ERROR;
return 0;
}
static int ext_supported_groups_add_serverhello(SSL *ssl, CBB *out) {
/* Servers don't echo this extension. */
return 1;
}
/* kExtensions contains all the supported extensions. */
static const struct tls_extension kExtensions[] = {
{
/* The renegotiation extension must always be at index zero because the
* |received| and |sent| bitsets need to be tweaked when the "extension" is
* sent as an SCSV. */
TLSEXT_TYPE_renegotiate,
NULL,
ext_ri_add_clienthello,
ext_ri_parse_serverhello,
ext_ri_parse_clienthello,
ext_ri_add_serverhello,
},
{
TLSEXT_TYPE_server_name,
ext_sni_init,
ext_sni_add_clienthello,
ext_sni_parse_serverhello,
ext_sni_parse_clienthello,
ext_sni_add_serverhello,
},
{
TLSEXT_TYPE_extended_master_secret,
ext_ems_init,
ext_ems_add_clienthello,
ext_ems_parse_serverhello,
ext_ems_parse_clienthello,
ext_ems_add_serverhello,
},
{
TLSEXT_TYPE_session_ticket,
NULL,
ext_ticket_add_clienthello,
ext_ticket_parse_serverhello,
ext_ticket_parse_clienthello,
ext_ticket_add_serverhello,
},
{
TLSEXT_TYPE_signature_algorithms,
NULL,
ext_sigalgs_add_clienthello,
ext_sigalgs_parse_serverhello,
ext_sigalgs_parse_clienthello,
ext_sigalgs_add_serverhello,
},
{
TLSEXT_TYPE_status_request,
ext_ocsp_init,
ext_ocsp_add_clienthello,
ext_ocsp_parse_serverhello,
ext_ocsp_parse_clienthello,
ext_ocsp_add_serverhello,
},
{
TLSEXT_TYPE_next_proto_neg,
ext_npn_init,
ext_npn_add_clienthello,
ext_npn_parse_serverhello,
ext_npn_parse_clienthello,
ext_npn_add_serverhello,
},
{
TLSEXT_TYPE_certificate_timestamp,
NULL,
ext_sct_add_clienthello,
ext_sct_parse_serverhello,
ext_sct_parse_clienthello,
ext_sct_add_serverhello,
},
{
TLSEXT_TYPE_application_layer_protocol_negotiation,
ext_alpn_init,
ext_alpn_add_clienthello,
ext_alpn_parse_serverhello,
ext_alpn_parse_clienthello,
ext_alpn_add_serverhello,
},
{
TLSEXT_TYPE_channel_id,
ext_channel_id_init,
ext_channel_id_add_clienthello,
ext_channel_id_parse_serverhello,
ext_channel_id_parse_clienthello,
ext_channel_id_add_serverhello,
},
{
TLSEXT_TYPE_srtp,
ext_srtp_init,
ext_srtp_add_clienthello,
ext_srtp_parse_serverhello,
ext_srtp_parse_clienthello,
ext_srtp_add_serverhello,
},
{
TLSEXT_TYPE_ec_point_formats,
NULL,
ext_ec_point_add_clienthello,
ext_ec_point_parse_serverhello,
ext_ec_point_parse_clienthello,
ext_ec_point_add_serverhello,
},
/* 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,
ext_supported_groups_init,
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 *)NULL)->s3->tmp.extensions.sent) * 8,
too_many_extensions_for_sent_bitset);
OPENSSL_COMPILE_ASSERT(kNumExtensions <=
sizeof(((SSL *)NULL)->s3->tmp.extensions.received) *
8,
too_many_extensions_for_received_bitset);
static const struct tls_extension *tls_extension_find(uint32_t *out_index,
uint16_t value) {
unsigned i;
for (i = 0; i < kNumExtensions; i++) {
if (kExtensions[i].value == value) {
*out_index = i;
return &kExtensions[i];
}
}
return NULL;
}
int SSL_extension_supported(unsigned extension_value) {
uint32_t index;
return extension_value == TLSEXT_TYPE_padding ||
tls_extension_find(&index, extension_value) != NULL;
}
int ssl_add_clienthello_tlsext(SSL *ssl, CBB *out, size_t header_len) {
/* don't add extensions for SSLv3 unless doing secure renegotiation */
if (ssl->client_version == SSL3_VERSION &&
!ssl->s3->send_connection_binding) {
return 1;
}
CBB extensions;
if (!CBB_add_u16_length_prefixed(out, &extensions)) {
goto err;
}
ssl->s3->tmp.extensions.sent = 0;
ssl->s3->tmp.custom_extensions.sent = 0;
size_t i;
for (i = 0; i < kNumExtensions; i++) {
if (kExtensions[i].init != NULL) {
kExtensions[i].init(ssl);
}
}
for (i = 0; i < kNumExtensions; i++) {
const size_t len_before = CBB_len(&extensions);
if (!kExtensions[i].add_clienthello(ssl, &extensions)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_ERROR_ADDING_EXTENSION);
ERR_add_error_dataf("extension: %u", (unsigned)kExtensions[i].value);
goto err;
}
if (CBB_len(&extensions) != len_before) {
ssl->s3->tmp.extensions.sent |= (1u << i);
}
}
if (!custom_ext_add_clienthello(ssl, &extensions)) {
goto err;
}
if (!SSL_IS_DTLS(ssl)) {
header_len += 2 + CBB_len(&extensions);
if (header_len > 0xff && header_len < 0x200) {
/* Add padding to workaround bugs in F5 terminators. See RFC 7685.
*
* NB: because this code works out the length of all existing extensions
* it MUST always appear last. */
size_t padding_len = 0x200 - header_len;
/* Extensions take at least four bytes to encode. Always include at least
* one byte of data if including the extension. WebSphere Application
* Server 7.0 is intolerant to the last extension being zero-length. See
* https://crbug.com/363583. */
if (padding_len >= 4 + 1) {
padding_len -= 4;
} else {
padding_len = 1;
}
uint8_t *padding_bytes;
if (!CBB_add_u16(&extensions, TLSEXT_TYPE_padding) ||
!CBB_add_u16(&extensions, padding_len) ||
!CBB_add_space(&extensions, &padding_bytes, padding_len)) {
goto err;
}
memset(padding_bytes, 0, padding_len);
}
}
/* Discard empty extensions blocks. */
if (CBB_len(&extensions) == 0) {
CBB_discard_child(out);
}
return CBB_flush(out);
err:
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
return 0;
}
int ssl_add_serverhello_tlsext(SSL *ssl, CBB *out) {
CBB extensions;
if (!CBB_add_u16_length_prefixed(out, &extensions)) {
goto err;
}
unsigned i;
for (i = 0; i < kNumExtensions; i++) {
if (!(ssl->s3->tmp.extensions.received & (1u << i))) {
/* Don't send extensions that were not received. */
continue;
}
if (!kExtensions[i].add_serverhello(ssl, &extensions)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_ERROR_ADDING_EXTENSION);
ERR_add_error_dataf("extension: %u", (unsigned)kExtensions[i].value);
goto err;
}
}
if (!custom_ext_add_serverhello(ssl, &extensions)) {
goto err;
}
/* Discard empty extensions blocks. */
if (CBB_len(&extensions) == 0) {
CBB_discard_child(out);
}
return CBB_flush(out);
err:
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
return 0;
}
static int ssl_scan_clienthello_tlsext(SSL *ssl, CBS *cbs, int *out_alert) {
size_t i;
for (i = 0; i < kNumExtensions; i++) {
if (kExtensions[i].init != NULL) {
kExtensions[i].init(ssl);
}
}
ssl->s3->tmp.extensions.received = 0;
ssl->s3->tmp.custom_extensions.received = 0;
/* The renegotiation extension must always be at index zero because the
* |received| and |sent| bitsets need to be tweaked when the "extension" is
* sent as an SCSV. */
assert(kExtensions[0].value == TLSEXT_TYPE_renegotiate);
/* There may be no extensions. */
if (CBS_len(cbs) != 0) {
/* Decode the extensions block and check it is valid. */
CBS extensions;
if (!CBS_get_u16_length_prefixed(cbs, &extensions) ||
!tls1_check_duplicate_extensions(&extensions)) {
*out_alert = SSL_AD_DECODE_ERROR;
return 0;
}
while (CBS_len(&extensions) != 0) {
uint16_t type;
CBS extension;
/* Decode the next extension. */
if (!CBS_get_u16(&extensions, &type) ||
!CBS_get_u16_length_prefixed(&extensions, &extension)) {
*out_alert = SSL_AD_DECODE_ERROR;
return 0;
}
/* RFC 5746 made the existence of extensions in SSL 3.0 somewhat
* ambiguous. Ignore all but the renegotiation_info extension. */
if (ssl->version == SSL3_VERSION && type != TLSEXT_TYPE_renegotiate) {
continue;
}
unsigned ext_index;
const struct tls_extension *const ext =
tls_extension_find(&ext_index, type);
if (ext == NULL) {
if (!custom_ext_parse_clienthello(ssl, out_alert, type, &extension)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_ERROR_PARSING_EXTENSION);
return 0;
}
continue;
}
ssl->s3->tmp.extensions.received |= (1u << ext_index);
uint8_t alert = SSL_AD_DECODE_ERROR;
if (!ext->parse_clienthello(ssl, &alert, &extension)) {
*out_alert = alert;
OPENSSL_PUT_ERROR(SSL, SSL_R_ERROR_PARSING_EXTENSION);
ERR_add_error_dataf("extension: %u", (unsigned)type);
return 0;
}
}
}
for (i = 0; i < kNumExtensions; i++) {
if (!(ssl->s3->tmp.extensions.received & (1u << i))) {
/* Extension wasn't observed so call the callback with a NULL
* parameter. */
uint8_t alert = SSL_AD_DECODE_ERROR;
if (!kExtensions[i].parse_clienthello(ssl, &alert, NULL)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_MISSING_EXTENSION);
ERR_add_error_dataf("extension: %u", (unsigned)kExtensions[i].value);
*out_alert = alert;
return 0;
}
}
}
return 1;
}
int ssl_parse_clienthello_tlsext(SSL *ssl, CBS *cbs) {
int alert = -1;
if (ssl_scan_clienthello_tlsext(ssl, cbs, &alert) <= 0) {
ssl3_send_alert(ssl, SSL3_AL_FATAL, alert);
return 0;
}
if (ssl_check_clienthello_tlsext(ssl) <= 0) {
OPENSSL_PUT_ERROR(SSL, SSL_R_CLIENTHELLO_TLSEXT);
return 0;
}
return 1;
}
OPENSSL_COMPILE_ASSERT(kNumExtensions <= sizeof(uint32_t) * 8, too_many_bits);
static int ssl_scan_serverhello_tlsext(SSL *ssl, CBS *cbs, int *out_alert) {
uint32_t received = 0;
if (CBS_len(cbs) != 0) {
/* Decode the extensions block and check it is valid. */
CBS extensions;
if (!CBS_get_u16_length_prefixed(cbs, &extensions) ||
!tls1_check_duplicate_extensions(&extensions)) {
*out_alert = SSL_AD_DECODE_ERROR;
return 0;
}
while (CBS_len(&extensions) != 0) {
uint16_t type;
CBS extension;
/* Decode the next extension. */
if (!CBS_get_u16(&extensions, &type) ||
!CBS_get_u16_length_prefixed(&extensions, &extension)) {
*out_alert = SSL_AD_DECODE_ERROR;
return 0;
}
unsigned ext_index;
const struct tls_extension *const ext =
tls_extension_find(&ext_index, type);
if (ext == NULL) {
if (!custom_ext_parse_serverhello(ssl, out_alert, type, &extension)) {
return 0;
}
continue;
}
if (!(ssl->s3->tmp.extensions.sent & (1u << ext_index))) {
/* If the extension was never sent then it is illegal. */
OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_EXTENSION);
ERR_add_error_dataf("extension :%u", (unsigned)type);
*out_alert = SSL_AD_DECODE_ERROR;
return 0;
}
received |= (1u << ext_index);
uint8_t alert = SSL_AD_DECODE_ERROR;
if (!ext->parse_serverhello(ssl, &alert, &extension)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_ERROR_PARSING_EXTENSION);
ERR_add_error_dataf("extension: %u", (unsigned)type);
*out_alert = alert;
return 0;
}
}
}
size_t i;
for (i = 0; i < kNumExtensions; i++) {
if (!(received & (1u << i))) {
/* Extension wasn't observed so call the callback with a NULL
* parameter. */
uint8_t alert = SSL_AD_DECODE_ERROR;
if (!kExtensions[i].parse_serverhello(ssl, &alert, NULL)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_MISSING_EXTENSION);
ERR_add_error_dataf("extension: %u", (unsigned)kExtensions[i].value);
*out_alert = alert;
return 0;
}
}
}
return 1;
}
static int ssl_check_clienthello_tlsext(SSL *ssl) {
int ret = SSL_TLSEXT_ERR_NOACK;
int al = SSL_AD_UNRECOGNIZED_NAME;
if (ssl->ctx->tlsext_servername_callback != 0) {
ret = ssl->ctx->tlsext_servername_callback(ssl, &al,
ssl->ctx->tlsext_servername_arg);
} else if (ssl->initial_ctx->tlsext_servername_callback != 0) {
ret = ssl->initial_ctx->tlsext_servername_callback(
ssl, &al, ssl->initial_ctx->tlsext_servername_arg);
}
switch (ret) {
case SSL_TLSEXT_ERR_ALERT_FATAL:
ssl3_send_alert(ssl, SSL3_AL_FATAL, al);
return -1;
case SSL_TLSEXT_ERR_ALERT_WARNING:
ssl3_send_alert(ssl, SSL3_AL_WARNING, al);
return 1;
case SSL_TLSEXT_ERR_NOACK:
ssl->s3->tmp.should_ack_sni = 0;
return 1;
default:
return 1;
}
}
static int ssl_check_serverhello_tlsext(SSL *ssl) {
int ret = SSL_TLSEXT_ERR_OK;
int al = SSL_AD_UNRECOGNIZED_NAME;
if (ssl->ctx->tlsext_servername_callback != 0) {
ret = ssl->ctx->tlsext_servername_callback(ssl, &al,
ssl->ctx->tlsext_servername_arg);
} else if (ssl->initial_ctx->tlsext_servername_callback != 0) {
ret = ssl->initial_ctx->tlsext_servername_callback(
ssl, &al, ssl->initial_ctx->tlsext_servername_arg);
}
switch (ret) {
case SSL_TLSEXT_ERR_ALERT_FATAL:
ssl3_send_alert(ssl, SSL3_AL_FATAL, al);
return -1;
case SSL_TLSEXT_ERR_ALERT_WARNING:
ssl3_send_alert(ssl, SSL3_AL_WARNING, al);
return 1;
default:
return 1;
}
}
int ssl_parse_serverhello_tlsext(SSL *ssl, CBS *cbs) {
int alert = -1;
if (ssl_scan_serverhello_tlsext(ssl, cbs, &alert) <= 0) {
ssl3_send_alert(ssl, SSL3_AL_FATAL, alert);
return 0;
}
if (ssl_check_serverhello_tlsext(ssl) <= 0) {
OPENSSL_PUT_ERROR(SSL, SSL_R_SERVERHELLO_TLSEXT);
return 0;
}
return 1;
}
int tls_process_ticket(SSL *ssl, SSL_SESSION **out_session,
int *out_renew_ticket, const uint8_t *ticket,
size_t ticket_len, const uint8_t *session_id,
size_t session_id_len) {
int ret = 1; /* Most errors are non-fatal. */
SSL_CTX *ssl_ctx = ssl->initial_ctx;
uint8_t *plaintext = NULL;
HMAC_CTX hmac_ctx;
HMAC_CTX_init(&hmac_ctx);
EVP_CIPHER_CTX cipher_ctx;
EVP_CIPHER_CTX_init(&cipher_ctx);
*out_renew_ticket = 0;
*out_session = NULL;
if (session_id_len > SSL_MAX_SSL_SESSION_ID_LENGTH) {
goto done;
}
/* Ensure there is room for the key name and the largest IV
* |tlsext_ticket_key_cb| may try to consume. The real limit may be lower, but
* the maximum IV length should be well under the minimum size for the
* session material and HMAC. */
if (ticket_len < SSL_TICKET_KEY_NAME_LEN + EVP_MAX_IV_LENGTH) {
goto done;
}
const uint8_t *iv = ticket + SSL_TICKET_KEY_NAME_LEN;
if (ssl_ctx->tlsext_ticket_key_cb != NULL) {
int cb_ret = ssl_ctx->tlsext_ticket_key_cb(
ssl, (uint8_t *)ticket /* name */, (uint8_t *)iv, &cipher_ctx,
&hmac_ctx, 0 /* decrypt */);
if (cb_ret < 0) {
ret = 0;
goto done;
}
if (cb_ret == 0) {
goto done;
}
if (cb_ret == 2) {
*out_renew_ticket = 1;
}
} else {
/* Check the key name matches. */
if (memcmp(ticket, ssl_ctx->tlsext_tick_key_name,
SSL_TICKET_KEY_NAME_LEN) != 0) {
goto done;
}
if (!HMAC_Init_ex(&hmac_ctx, ssl_ctx->tlsext_tick_hmac_key,
sizeof(ssl_ctx->tlsext_tick_hmac_key), tlsext_tick_md(),
NULL) ||
!EVP_DecryptInit_ex(&cipher_ctx, EVP_aes_128_cbc(), NULL,
ssl_ctx->tlsext_tick_aes_key, iv)) {
ret = 0;
goto done;
}
}
size_t iv_len = EVP_CIPHER_CTX_iv_length(&cipher_ctx);
/* Check the MAC at the end of the ticket. */
uint8_t mac[EVP_MAX_MD_SIZE];
size_t mac_len = HMAC_size(&hmac_ctx);
if (ticket_len < SSL_TICKET_KEY_NAME_LEN + iv_len + 1 + mac_len) {
/* The ticket must be large enough for key name, IV, data, and MAC. */
goto done;
}
HMAC_Update(&hmac_ctx, ticket, ticket_len - mac_len);
HMAC_Final(&hmac_ctx, mac, NULL);
if (CRYPTO_memcmp(mac, ticket + (ticket_len - mac_len), mac_len) != 0) {
goto done;
}
/* Decrypt the session data. */
const uint8_t *ciphertext = ticket + SSL_TICKET_KEY_NAME_LEN + iv_len;
size_t ciphertext_len = ticket_len - SSL_TICKET_KEY_NAME_LEN - iv_len -
mac_len;
plaintext = OPENSSL_malloc(ciphertext_len);
if (plaintext == NULL) {
ret = 0;
goto done;
}
if (ciphertext_len >= INT_MAX) {
goto done;
}
int len1, len2;
if (!EVP_DecryptUpdate(&cipher_ctx, plaintext, &len1, ciphertext,
(int)ciphertext_len) ||
!EVP_DecryptFinal_ex(&cipher_ctx, plaintext + len1, &len2)) {
ERR_clear_error(); /* Don't leave an error on the queue. */
goto done;
}
/* Decode the session. */
SSL_SESSION *session = SSL_SESSION_from_bytes(plaintext, len1 + len2);
if (session == NULL) {
ERR_clear_error(); /* Don't leave an error on the queue. */
goto done;
}
/* Copy the client's session ID into the new session, to denote the ticket has
* been accepted. */
memcpy(session->session_id, session_id, session_id_len);
session->session_id_length = session_id_len;
*out_session = session;
done:
OPENSSL_free(plaintext);
HMAC_CTX_cleanup(&hmac_ctx);
EVP_CIPHER_CTX_cleanup(&cipher_ctx);
return ret;
}
/* Tables to translate from NIDs to TLS v1.2 ids */
typedef struct {
int nid;
int id;
} tls12_lookup;
static const tls12_lookup tls12_md[] = {
{NID_sha1, TLSEXT_hash_sha1},
{NID_sha256, TLSEXT_hash_sha256},
{NID_sha384, TLSEXT_hash_sha384},
{NID_sha512, TLSEXT_hash_sha512},
};
static const tls12_lookup tls12_sig[] = {{EVP_PKEY_RSA, TLSEXT_signature_rsa},
{EVP_PKEY_EC, TLSEXT_signature_ecdsa}};
static int tls12_find_id(int nid, const tls12_lookup *table, size_t tlen) {
size_t i;
for (i = 0; i < tlen; i++) {
if (table[i].nid == nid) {
return table[i].id;
}
}
return -1;
}
int tls12_get_sigid(int pkey_type) {
return tls12_find_id(pkey_type, tls12_sig,
sizeof(tls12_sig) / sizeof(tls12_lookup));
}
int tls12_add_sigandhash(SSL *ssl, CBB *out, const EVP_MD *md) {
int md_id = tls12_find_id(EVP_MD_type(md), tls12_md,
sizeof(tls12_md) / sizeof(tls12_lookup));
int sig_id = tls12_get_sigid(ssl_private_key_type(ssl));
return md_id != -1 &&
sig_id != -1 &&
CBB_add_u8(out, (uint8_t)md_id) &&
CBB_add_u8(out, (uint8_t)sig_id);
}
const EVP_MD *tls12_get_hash(uint8_t hash_alg) {
switch (hash_alg) {
case TLSEXT_hash_sha1:
return EVP_sha1();
case TLSEXT_hash_sha256:
return EVP_sha256();
case TLSEXT_hash_sha384:
return EVP_sha384();
case TLSEXT_hash_sha512:
return EVP_sha512();
default:
return NULL;
}
}
/* tls12_get_pkey_type returns the EVP_PKEY type corresponding to TLS signature
* algorithm |sig_alg|. It returns -1 if the type is unknown. */
static int tls12_get_pkey_type(uint8_t sig_alg) {
switch (sig_alg) {
case TLSEXT_signature_rsa:
return EVP_PKEY_RSA;
case TLSEXT_signature_ecdsa:
return EVP_PKEY_EC;
default:
return -1;
}
}
OPENSSL_COMPILE_ASSERT(sizeof(TLS_SIGALGS) == 2,
sizeof_tls_sigalgs_is_not_two);
int tls1_parse_peer_sigalgs(SSL *ssl, const CBS *in_sigalgs) {
/* Extension ignored for inappropriate versions */
if (ssl3_protocol_version(ssl) < TLS1_2_VERSION) {
return 1;
}
CERT *const cert = ssl->cert;
OPENSSL_free(cert->peer_sigalgs);
cert->peer_sigalgs = NULL;
cert->peer_sigalgslen = 0;
size_t num_sigalgs = CBS_len(in_sigalgs);
if (num_sigalgs % 2 != 0) {
return 0;
}
num_sigalgs /= 2;
/* supported_signature_algorithms in the certificate request is
* allowed to be empty. */
if (num_sigalgs == 0) {
return 1;
}
/* This multiplication doesn't overflow because sizeof(TLS_SIGALGS) is two
* (statically asserted above) and we just divided |num_sigalgs| by two. */
cert->peer_sigalgs = OPENSSL_malloc(num_sigalgs * sizeof(TLS_SIGALGS));
if (cert->peer_sigalgs == NULL) {
return 0;
}
cert->peer_sigalgslen = num_sigalgs;
CBS sigalgs;
CBS_init(&sigalgs, CBS_data(in_sigalgs), CBS_len(in_sigalgs));
size_t i;
for (i = 0; i < num_sigalgs; i++) {
TLS_SIGALGS *const sigalg = &cert->peer_sigalgs[i];
if (!CBS_get_u8(&sigalgs, &sigalg->rhash) ||
!CBS_get_u8(&sigalgs, &sigalg->rsign)) {
return 0;
}
}
return 1;
}
const EVP_MD *tls1_choose_signing_digest(SSL *ssl) {
CERT *cert = ssl->cert;
int type = ssl_private_key_type(ssl);
size_t i, j;
static const int kDefaultDigestList[] = {NID_sha256, NID_sha384, NID_sha512,
NID_sha1};
const int *digest_nids = kDefaultDigestList;
size_t num_digest_nids =
sizeof(kDefaultDigestList) / sizeof(kDefaultDigestList[0]);
if (cert->digest_nids != NULL) {
digest_nids = cert->digest_nids;
num_digest_nids = cert->num_digest_nids;
}
for (i = 0; i < num_digest_nids; i++) {
const int digest_nid = digest_nids[i];
for (j = 0; j < cert->peer_sigalgslen; j++) {
const EVP_MD *md = tls12_get_hash(cert->peer_sigalgs[j].rhash);
if (md == NULL ||
digest_nid != EVP_MD_type(md) ||
tls12_get_pkey_type(cert->peer_sigalgs[j].rsign) != type) {
continue;
}
return md;
}
}
/* If no suitable digest may be found, default to SHA-1. */
return EVP_sha1();
}
int tls1_channel_id_hash(SSL *ssl, uint8_t *out, size_t *out_len) {
int ret = 0;
EVP_MD_CTX ctx;
EVP_MD_CTX_init(&ctx);
if (!EVP_DigestInit_ex(&ctx, EVP_sha256(), NULL)) {
goto err;
}
static const char kClientIDMagic[] = "TLS Channel ID signature";
EVP_DigestUpdate(&ctx, kClientIDMagic, sizeof(kClientIDMagic));
if (ssl->hit) {
static const char kResumptionMagic[] = "Resumption";
EVP_DigestUpdate(&ctx, kResumptionMagic, sizeof(kResumptionMagic));
if (ssl->session->original_handshake_hash_len == 0) {
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
goto err;
}
EVP_DigestUpdate(&ctx, ssl->session->original_handshake_hash,
ssl->session->original_handshake_hash_len);
}
uint8_t handshake_hash[EVP_MAX_MD_SIZE];
int handshake_hash_len = tls1_handshake_digest(ssl, handshake_hash,
sizeof(handshake_hash));
if (handshake_hash_len < 0) {
goto err;
}
EVP_DigestUpdate(&ctx, handshake_hash, (size_t)handshake_hash_len);
unsigned len_u;
EVP_DigestFinal_ex(&ctx, out, &len_u);
*out_len = len_u;
ret = 1;
err:
EVP_MD_CTX_cleanup(&ctx);
return ret;
}
/* tls1_record_handshake_hashes_for_channel_id records the current handshake
* hashes in |ssl->session| so that Channel ID resumptions can sign that
* data. */
int tls1_record_handshake_hashes_for_channel_id(SSL *ssl) {
int digest_len;
/* This function should never be called for a resumed session because the
* handshake hashes that we wish to record are for the original, full
* handshake. */
if (ssl->hit) {
return -1;
}
digest_len =
tls1_handshake_digest(ssl, ssl->session->original_handshake_hash,
sizeof(ssl->session->original_handshake_hash));
if (digest_len < 0) {
return -1;
}
ssl->session->original_handshake_hash_len = digest_len;
return 1;
}
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