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boringssl/ssl/t1_lib.c
David Benjamin 9e68f19e1b Add SSL_get_curve_id and SSL_get_dhe_group_size. 
This replaces the old key_exchange_info APIs and does not require the
caller be aware of the mess around SSL_SESSION management. They
currently have the same bugs around renegotiation as before, but later
work to fix up SSL_SESSION tracking will fix their internals.

For consistency with the existing functions, I've kept the public API at
'curve' rather than 'group' for now. I think it's probably better to
have only one name with a single explanation in the section header
rather than half and half. (I also wouldn't be surprised if the IETF
ends up renaming 'group' again to 'key exchange' at some point.  We'll
see what happens.)

Change-Id: I8e90a503bc4045d12f30835c86de64ef9f2d07c8
Reviewed-on: https://boringssl-review.googlesource.com/8565
Reviewed-by: Adam Langley <agl@google.com>
2016-06-30 23:20:34 +00:00

2719 lines
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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_CURVE_X25519,
SSL_CURVE_SECP256R1,
SSL_CURVE_SECP384R1,
#if defined(BORINGSSL_ANDROID_SYSTEM)
SSL_CURVE_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. */
static const uint16_t kDefaultSignatureAlgorithms[] = {
SSL_SIGN_RSA_PKCS1_SHA512,
SSL_SIGN_ECDSA_SECP521R1_SHA512,
SSL_SIGN_RSA_PKCS1_SHA384,
SSL_SIGN_ECDSA_SECP384R1_SHA384,
SSL_SIGN_RSA_PKCS1_SHA256,
SSL_SIGN_ECDSA_SECP256R1_SHA256,
SSL_SIGN_RSA_PKCS1_SHA1,
SSL_SIGN_ECDSA_SHA1,
};
size_t tls12_get_psigalgs(SSL *ssl, const uint16_t **psigs) {
*psigs = kDefaultSignatureAlgorithms;
return sizeof(kDefaultSignatureAlgorithms) /
sizeof(kDefaultSignatureAlgorithms[0]);
}
static int tls12_get_pkey_type(uint16_t sigalg);
int tls12_check_peer_sigalg(SSL *ssl, int *out_alert,
uint16_t sigalg, EVP_PKEY *pkey) {
const uint16_t *sent_sigs;
size_t sent_sigslen, i;
/* Check key type is consistent with signature */
if (pkey->type != tls12_get_pkey_type(sigalg)) {
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++) {
if (sigalg == sent_sigs[i]) {
break;
}
}
if (i == sent_sigslen) {
OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_SIGNATURE_TYPE);
*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 uint16_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++) {
switch (sigalgs[i]) {
case SSL_SIGN_RSA_PKCS1_SHA512:
case SSL_SIGN_RSA_PKCS1_SHA384:
case SSL_SIGN_RSA_PKCS1_SHA256:
case SSL_SIGN_RSA_PKCS1_SHA1:
have_rsa = 1;
break;
case SSL_SIGN_ECDSA_SECP521R1_SHA512:
case SSL_SIGN_ECDSA_SECP384R1_SHA384:
case SSL_SIGN_ECDSA_SECP256R1_SHA256:
case SSL_SIGN_ECDSA_SHA1:
have_ecdsa = 1;
break;
}
}
/* Disable auth if we don't include any appropriate signature algorithms. */
if (!have_rsa) {
c->mask_a |= SSL_aRSA;
}
if (!have_ecdsa) {
c->mask_a |= SSL_aECDSA;
}
/* with PSK there must be client callback set */
if (!ssl->psk_client_callback) {
c->mask_a |= SSL_aPSK;
c->mask_k |= SSL_kPSK;
}
}
/* tls_extension represents a TLS extension that is handled internally. The
* |init| function is called for each handshake, before any other functions of
* the extension. Then the add and parse callbacks are called as needed.
*
* The parse callbacks receive a |CBS| that contains the contents of the
* extension (i.e. not including the type and length bytes). If an extension is
* not received then the parse callbacks will be called with a NULL CBS so that
* they can do any processing needed to handle the absence of an extension.
*
* The add callbacks receive a |CBB| to which the extension can be appended but
* the function is responsible for appending the type and length bytes too.
*
* All callbacks return one for success and zero for error. If a parse function
* returns zero then a fatal alert with value |*out_alert| will be sent. If
* |*out_alert| isn't set, then a |decode_error| alert will be sent. */
struct tls_extension {
uint16_t value;
void (*init)(SSL *ssl);
int (*add_clienthello)(SSL *ssl, CBB *out);
int (*parse_serverhello)(SSL *ssl, uint8_t *out_alert, CBS *contents);
int (*parse_clienthello)(SSL *ssl, uint8_t *out_alert, CBS *contents);
int (*add_serverhello)(SSL *ssl, CBB *out);
};
/* 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 (ssl->method->version_from_wire(ssl->client_version) < TLS1_2_VERSION) {
return 1;
}
const uint16_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)) {
return 0;
}
size_t i;
for (i = 0; i < sigalgs_len; i++) {
if (!CBB_add_u16(&sigalgs, sigalgs_data[i])) {
return 0;
}
}
if (!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;
}
const EVP_MD *tls12_get_hash(uint16_t sigalg) {
if (sigalg == SSL_SIGN_RSA_PKCS1_MD5_SHA1) {
return EVP_md5_sha1();
}
switch (sigalg >> 8) {
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 |sigalg|. It returns -1 if the type is unknown. */
static int tls12_get_pkey_type(uint16_t sigalg) {
switch (sigalg & 0xff) {
case TLSEXT_signature_rsa:
return EVP_PKEY_RSA;
case TLSEXT_signature_ecdsa:
return EVP_PKEY_EC;
default:
return -1;
}
}
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(uint16_t) is two
* and we just divided |num_sigalgs| by two. */
cert->peer_sigalgs = OPENSSL_malloc(num_sigalgs * sizeof(uint16_t));
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++) {
if (!CBS_get_u16(&sigalgs, &cert->peer_sigalgs[i])) {
return 0;
}
}
return 1;
}
uint16_t tls1_choose_signature_algorithm(SSL *ssl) {
CERT *cert = ssl->cert;
int type = ssl_private_key_type(ssl);
size_t i, j;
/* Before TLS 1.2, the signature algorithm isn't negotiated as part of the
* handshake. It is fixed at MD5-SHA1 for RSA and SHA1 for ECDSA. */
if (ssl3_protocol_version(ssl) < TLS1_2_VERSION) {
if (type == EVP_PKEY_RSA) {
return SSL_SIGN_RSA_PKCS1_MD5_SHA1;
}
return SSL_SIGN_ECDSA_SHA1;
}
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++) {
uint16_t signature_algorithm = cert->peer_sigalgs[j];
/* SSL_SIGN_RSA_PKCS1_MD5_SHA1 is an internal value and should never be
* negotiated. */
if (signature_algorithm == SSL_SIGN_RSA_PKCS1_MD5_SHA1) {
continue;
}
const EVP_MD *md = tls12_get_hash(signature_algorithm);
if (md != NULL && EVP_MD_type(md) == digest_nid &&
tls12_get_pkey_type(signature_algorithm) == type) {
return signature_algorithm;
}
}
}
/* If no suitable digest may be found, default to SHA-1. */
if (type == EVP_PKEY_RSA) {
return SSL_SIGN_RSA_PKCS1_SHA1;
}
return SSL_SIGN_ECDSA_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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