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0fc431a0d7
boringssl/ssl/t1_lib.c
David Benjamin 0fc431a0d7 Prune NIDs from TLS_SIGALGS. 
There's no need to store more than the TLS values.

Change-Id: I1a93c7c6aa3254caf7cc09969da52713e6f8acf4
Reviewed-on: https://boringssl-review.googlesource.com/5348
Reviewed-by: Adam Langley <agl@google.com>
2015-07-07 01:14:40 +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 <assert.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <openssl/bytestring.h>
#include <openssl/err.h>
#include <openssl/evp.h>
#include <openssl/hmac.h>
#include <openssl/mem.h>
#include <openssl/obj.h>
#include <openssl/rand.h>
#include "internal.h"
static int ssl_check_clienthello_tlsext(SSL *s);
static int ssl_check_serverhello_tlsext(SSL *s);
const SSL3_ENC_METHOD TLSv1_enc_data = {
tls1_prf,
tls1_setup_key_block,
tls1_generate_master_secret,
tls1_change_cipher_state,
tls1_final_finish_mac,
tls1_cert_verify_mac,
TLS_MD_CLIENT_FINISH_CONST,TLS_MD_CLIENT_FINISH_CONST_SIZE,
TLS_MD_SERVER_FINISH_CONST,TLS_MD_SERVER_FINISH_CONST_SIZE,
tls1_alert_code,
tls1_export_keying_material,
0,
};
const SSL3_ENC_METHOD TLSv1_1_enc_data = {
tls1_prf,
tls1_setup_key_block,
tls1_generate_master_secret,
tls1_change_cipher_state,
tls1_final_finish_mac,
tls1_cert_verify_mac,
TLS_MD_CLIENT_FINISH_CONST,TLS_MD_CLIENT_FINISH_CONST_SIZE,
TLS_MD_SERVER_FINISH_CONST,TLS_MD_SERVER_FINISH_CONST_SIZE,
tls1_alert_code,
tls1_export_keying_material,
SSL_ENC_FLAG_EXPLICIT_IV,
};
const SSL3_ENC_METHOD TLSv1_2_enc_data = {
tls1_prf,
tls1_setup_key_block,
tls1_generate_master_secret,
tls1_change_cipher_state,
tls1_final_finish_mac,
tls1_cert_verify_mac,
TLS_MD_CLIENT_FINISH_CONST,TLS_MD_CLIENT_FINISH_CONST_SIZE,
TLS_MD_SERVER_FINISH_CONST,TLS_MD_SERVER_FINISH_CONST_SIZE,
tls1_alert_code,
tls1_export_keying_material,
SSL_ENC_FLAG_EXPLICIT_IV|SSL_ENC_FLAG_SIGALGS|SSL_ENC_FLAG_SHA256_PRF
|SSL_ENC_FLAG_TLS1_2_CIPHERS,
};
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 =
(uint16_t *)OPENSSL_malloc(sizeof(uint16_t) * num_extensions);
if (extension_types == NULL) {
OPENSSL_PUT_ERROR(SSL, tls1_check_duplicate_extensions,
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;
}
char 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;
}
struct tls_curve {
uint16_t curve_id;
int nid;
};
/* ECC curves from RFC4492. */
static const struct tls_curve tls_curves[] = {
{21, NID_secp224r1},
{23, NID_X9_62_prime256v1},
{24, NID_secp384r1},
{25, NID_secp521r1},
};
static const uint8_t ecformats_default[] = {
TLSEXT_ECPOINTFORMAT_uncompressed,
};
static const uint16_t eccurves_default[] = {
23, /* X9_62_prime256v1 */
24, /* secp384r1 */
};
int tls1_ec_curve_id2nid(uint16_t curve_id) {
size_t i;
for (i = 0; i < sizeof(tls_curves) / sizeof(tls_curves[0]); i++) {
if (curve_id == tls_curves[i].curve_id) {
return tls_curves[i].nid;
}
}
return NID_undef;
}
int tls1_ec_nid2curve_id(uint16_t *out_curve_id, int nid) {
size_t i;
for (i = 0; i < sizeof(tls_curves) / sizeof(tls_curves[0]); i++) {
if (nid == tls_curves[i].nid) {
*out_curve_id = tls_curves[i].curve_id;
return 1;
}
}
return 0;
}
/* tls1_get_curvelist sets |*out_curve_ids| and |*out_curve_ids_len| to the
* list of allowed curve IDs. If |get_peer_curves| is non-zero, return the
* peer's curve list. Otherwise, return the preferred list. */
static void tls1_get_curvelist(SSL *s, int get_peer_curves,
const uint16_t **out_curve_ids,
size_t *out_curve_ids_len) {
if (get_peer_curves) {
/* Only clients send a curve list, so this function is only called
* on the server. */
assert(s->server);
*out_curve_ids = s->s3->tmp.peer_ellipticcurvelist;
*out_curve_ids_len = s->s3->tmp.peer_ellipticcurvelist_length;
return;
}
*out_curve_ids = s->tlsext_ellipticcurvelist;
*out_curve_ids_len = s->tlsext_ellipticcurvelist_length;
if (!*out_curve_ids) {
*out_curve_ids = eccurves_default;
*out_curve_ids_len = sizeof(eccurves_default) / sizeof(eccurves_default[0]);
}
}
int tls1_check_curve(SSL *s, CBS *cbs, uint16_t *out_curve_id) {
uint8_t curve_type;
uint16_t curve_id;
const uint16_t *curves;
size_t curves_len, i;
/* Only support named curves. */
if (!CBS_get_u8(cbs, &curve_type) ||
curve_type != NAMED_CURVE_TYPE ||
!CBS_get_u16(cbs, &curve_id)) {
return 0;
}
tls1_get_curvelist(s, 0, &curves, &curves_len);
for (i = 0; i < curves_len; i++) {
if (curve_id == curves[i]) {
*out_curve_id = curve_id;
return 1;
}
}
return 0;
}
int tls1_get_shared_curve(SSL *s) {
const uint16_t *curves, *peer_curves, *pref, *supp;
size_t curves_len, peer_curves_len, pref_len, supp_len, i, j;
/* Can't do anything on client side */
if (s->server == 0) {
return NID_undef;
}
tls1_get_curvelist(s, 0 /* local curves */, &curves, &curves_len);
tls1_get_curvelist(s, 1 /* peer curves */, &peer_curves, &peer_curves_len);
if (peer_curves_len == 0) {
/* Clients are not required to send a supported_curves extension. In this
* case, the server is free to pick any curve it likes. See RFC 4492,
* section 4, paragraph 3. */
return (curves_len == 0) ? NID_undef : tls1_ec_curve_id2nid(curves[0]);
}
if (s->options & SSL_OP_CIPHER_SERVER_PREFERENCE) {
pref = curves;
pref_len = curves_len;
supp = peer_curves;
supp_len = peer_curves_len;
} else {
pref = peer_curves;
pref_len = peer_curves_len;
supp = curves;
supp_len = curves_len;
}
for (i = 0; i < pref_len; i++) {
for (j = 0; j < supp_len; j++) {
if (pref[i] == supp[j]) {
return tls1_ec_curve_id2nid(pref[i]);
}
}
}
return NID_undef;
}
int tls1_set_curves(uint16_t **out_curve_ids, size_t *out_curve_ids_len,
const int *curves, size_t ncurves) {
uint16_t *curve_ids;
size_t i;
curve_ids = (uint16_t *)OPENSSL_malloc(ncurves * sizeof(uint16_t));
if (curve_ids == NULL) {
return 0;
}
for (i = 0; i < ncurves; i++) {
if (!tls1_ec_nid2curve_id(&curve_ids[i], curves[i])) {
OPENSSL_free(curve_ids);
return 0;
}
}
OPENSSL_free(*out_curve_ids);
*out_curve_ids = curve_ids;
*out_curve_ids_len = ncurves;
return 1;
}
/* tls1_curve_params_from_ec_key sets |*out_curve_id| and |*out_comp_id| to the
* TLS curve 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_curve_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 curve ID */
nid = EC_GROUP_get_curve_name(grp);
if (!tls1_ec_nid2curve_id(&id, nid)) {
return 0;
}
/* Set the named curve ID. Arbitrary explicit curves are not supported. */
*out_curve_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_point_format returns one if |comp_id| is consistent with the
* peer's point format preferences. */
static int tls1_check_point_format(SSL *s, uint8_t comp_id) {
uint8_t *p = s->s3->tmp.peer_ecpointformatlist;
size_t plen = s->s3->tmp.peer_ecpointformatlist_length;
size_t i;
/* If point formats extension present check it, otherwise everything is
* supported (see RFC4492). */
if (p == NULL) {
return 1;
}
for (i = 0; i < plen; i++) {
if (comp_id == p[i]) {
return 1;
}
}
return 0;
}
/* tls1_check_curve_id returns one if |curve_id| is consistent with both our
* and the peer's curve preferences. Note: if called as the client, only our
* preferences are checked; the peer (the server) does not send preferences. */
static int tls1_check_curve_id(SSL *s, uint16_t curve_id) {
const uint16_t *curves;
size_t curves_len, i, get_peer_curves;
/* Check against our list, then the peer's list. */
for (get_peer_curves = 0; get_peer_curves <= 1; get_peer_curves++) {
if (get_peer_curves && !s->server) {
/* Servers do not present a preference list so, if we are a client, only
* check our list. */
continue;
}
tls1_get_curvelist(s, get_peer_curves, &curves, &curves_len);
if (get_peer_curves && curves_len == 0) {
/* Clients are not required to send a supported_curves extension. In this
* case, the server is free to pick any curve it likes. See RFC 4492,
* section 4, paragraph 3. */
continue;
}
for (i = 0; i < curves_len; i++) {
if (curves[i] == curve_id) {
break;
}
}
if (i == curves_len) {
return 0;
}
}
return 1;
}
static void tls1_get_formatlist(SSL *s, const uint8_t **pformats,
size_t *pformatslen) {
/* If we have a custom point format list use it otherwise use default */
if (s->tlsext_ecpointformatlist) {
*pformats = s->tlsext_ecpointformatlist;
*pformatslen = s->tlsext_ecpointformatlist_length;
} else {
*pformats = ecformats_default;
*pformatslen = sizeof(ecformats_default);
}
}
int tls1_check_ec_cert(SSL *s, X509 *x) {
int ret = 0;
EVP_PKEY *pkey = X509_get_pubkey(x);
uint16_t curve_id;
uint8_t comp_id;
if (!pkey ||
pkey->type != EVP_PKEY_EC ||
!tls1_curve_params_from_ec_key(&curve_id, &comp_id, pkey->pkey.ec) ||
!tls1_check_curve_id(s, curve_id) ||
!tls1_check_point_format(s, comp_id)) {
goto done;
}
ret = 1;
done:
EVP_PKEY_free(pkey);
return ret;
}
int tls1_check_ec_tmp_key(SSL *s) {
if (s->cert->ecdh_nid != NID_undef) {
/* If the curve is preconfigured, ECDH is acceptable iff the peer supports
* the curve. */
uint16_t curve_id;
return tls1_ec_nid2curve_id(&curve_id, s->cert->ecdh_nid) &&
tls1_check_curve_id(s, curve_id);
}
if (s->cert->ecdh_tmp_cb != NULL) {
/* Assume the callback will provide an acceptable curve. */
return 1;
}
/* Otherwise, the curve gets selected automatically. ECDH is acceptable iff
* there is a shared curve. */
return tls1_get_shared_curve(s) != NID_undef;
}
/* 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_sha224)
tlsext_sigalg(TLSEXT_hash_sha1)
};
size_t tls12_get_psigalgs(SSL *s, const uint8_t **psigs) {
/* If server use client authentication sigalgs if not NULL */
if (s->server && s->cert->client_sigalgs) {
*psigs = s->cert->client_sigalgs;
return s->cert->client_sigalgslen;
} else if (s->cert->conf_sigalgs) {
*psigs = s->cert->conf_sigalgs;
return s->cert->conf_sigalgslen;
} else {
*psigs = tls12_sigalgs;
return sizeof(tls12_sigalgs);
}
}
/* tls12_check_peer_sigalg parses a SignatureAndHashAlgorithm out of |cbs|. It
* checks it is consistent with |s|'s sent supported signature algorithms and,
* if so, writes the relevant digest into |*out_md| and returns 1. Otherwise it
* returns 0 and writes an alert into |*out_alert|. */
int tls12_check_peer_sigalg(const EVP_MD **out_md, int *out_alert, SSL *s,
CBS *cbs, EVP_PKEY *pkey) {
const uint8_t *sent_sigs;
size_t sent_sigslen, i;
int sigalg = tls12_get_sigid(pkey->type);
uint8_t hash, signature;
/* Should never happen */
if (sigalg == -1) {
OPENSSL_PUT_ERROR(SSL, tls12_check_peer_sigalg, ERR_R_INTERNAL_ERROR);
*out_alert = SSL_AD_INTERNAL_ERROR;
return 0;
}
if (!CBS_get_u8(cbs, &hash) ||
!CBS_get_u8(cbs, &signature)) {
OPENSSL_PUT_ERROR(SSL, tls12_check_peer_sigalg, SSL_R_DECODE_ERROR);
*out_alert = SSL_AD_DECODE_ERROR;
return 0;
}
/* Check key type is consistent with signature */
if (sigalg != signature) {
OPENSSL_PUT_ERROR(SSL, tls12_check_peer_sigalg, SSL_R_WRONG_SIGNATURE_TYPE);
*out_alert = SSL_AD_ILLEGAL_PARAMETER;
return 0;
}
if (pkey->type == EVP_PKEY_EC) {
uint16_t curve_id;
uint8_t comp_id;
/* Check compression and curve matches extensions */
if (!tls1_curve_params_from_ec_key(&curve_id, &comp_id, pkey->pkey.ec)) {
*out_alert = SSL_AD_INTERNAL_ERROR;
return 0;
}
if (s->server && (!tls1_check_curve_id(s, curve_id) ||
!tls1_check_point_format(s, comp_id))) {
OPENSSL_PUT_ERROR(SSL, tls12_check_peer_sigalg, SSL_R_WRONG_CURVE);
*out_alert = SSL_AD_ILLEGAL_PARAMETER;
return 0;
}
}
/* Check signature matches a type we sent */
sent_sigslen = tls12_get_psigalgs(s, &sent_sigs);
for (i = 0; i < sent_sigslen; i += 2, sent_sigs += 2) {
if (hash == sent_sigs[0] && signature == sent_sigs[1]) {
break;
}
}
/* Allow fallback to SHA-1. */
if (i == sent_sigslen && hash != TLSEXT_hash_sha1) {
OPENSSL_PUT_ERROR(SSL, tls12_check_peer_sigalg, 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, tls12_check_peer_sigalg, 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 *s) {
CERT *c = s->cert;
const uint8_t *sigalgs;
size_t i, sigalgslen;
int have_rsa = 0, have_ecdsa = 0;
c->mask_a = 0;
c->mask_k = 0;
/* Don't allow TLS 1.2 only ciphers if we don't suppport them */
if (!SSL_CLIENT_USE_TLS1_2_CIPHERS(s)) {
c->mask_ssl = SSL_TLSV1_2;
} else {
c->mask_ssl = 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(s, &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 (!s->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;
}
/* The servername extension is treated as follows:
*
* - Only the hostname type is supported with a maximum length of 255.
* - The servername is rejected if too long or if it contains zeros, in
* which case an fatal alert is generated.
* - The servername field is maintained together with the session cache.
* - When a session is resumed, the servername callback is invoked in order
* to allow the application to position itself to the right context.
* - The servername is acknowledged if it is new for a session or when
* it is identical to a previously used for the same session.
* Applications can control the behaviour. They can at any time
* set a 'desirable' servername for a new SSL object. This can be the
* case for example with HTTPS when a Host: header field is received and
* a renegotiation is requested. In this case, a possible servername
* presented in the new client hello is only acknowledged if it matches
* the value of the Host: field.
* - Applications must use SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION
* if they provide for changing an explicit servername context for the
* session,
* i.e. when the session has been established with a servername extension.
*/
CBS server_name_list;
char have_seen_host_name = 0;
if (!CBS_get_u16_length_prefixed(contents, &server_name_list) ||
CBS_len(&server_name_list) == 0 ||
CBS_len(contents) != 0) {
return 0;
}
/* Decode each ServerName in the extension. */
while (CBS_len(&server_name_list) > 0) {
uint8_t name_type;
CBS host_name;
if (!CBS_get_u8(&server_name_list, &name_type) ||
!CBS_get_u16_length_prefixed(&server_name_list, &host_name)) {
return 0;
}
/* Only host_name is supported. */
if (name_type != TLSEXT_NAMETYPE_host_name) {
continue;
}
if (have_seen_host_name) {
/* The ServerNameList MUST NOT contain more than one name of the same
* name_type. */
return 0;
}
have_seen_host_name = 1;
if (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;
}
if (!ssl->hit) {
assert(ssl->session->tlsext_hostname == NULL);
if (ssl->session->tlsext_hostname) {
/* This should be impossible. */
return 0;
}
/* 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) {
if (contents == NULL) {
/* No renegotiation extension received.
*
* 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.
*
* A lack of the extension is allowed if SSL_OP_LEGACY_SERVER_CONNECT is
* defined. */
if (ssl->options & SSL_OP_LEGACY_SERVER_CONNECT) {
return 1;
}
*out_alert = SSL_AD_HANDSHAKE_FAILURE;
OPENSSL_PUT_ERROR(SSL, ext_ri_parse_serverhello,
SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED);
return 0;
}
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, ext_ri_parse_serverhello,
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, ext_ri_parse_serverhello,
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, ext_ri_parse_serverhello,
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, ext_ri_parse_serverhello,
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, ext_ri_parse_clienthello,
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, ext_ri_parse_clienthello,
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;
}
/* 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,
},
};
#define kNumExtensions (sizeof(kExtensions) / sizeof(struct tls_extension))
OPENSSL_COMPILE_ASSERT(kNumExtensions <=
sizeof(((SSL *)NULL)->s3->tmp.extensions.sent) * 8,
too_many_extensions_for_bitset);
OPENSSL_COMPILE_ASSERT(kNumExtensions <=
sizeof(((SSL *)NULL)->s3->tmp.extensions.received) *
8,
too_many_extensions_for_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;
}
/* header_len is the length of the ClientHello header written so far, used to
* compute padding. It does not include the record header. Pass 0 if no padding
* is to be done. */
uint8_t *ssl_add_clienthello_tlsext(SSL *s, uint8_t *const buf,
uint8_t *const limit, size_t header_len) {
int extdatalen = 0;
uint8_t *ret = buf;
uint8_t *orig = buf;
/* See if we support any ECC ciphersuites */
int using_ecc = 0;
if (s->version >= TLS1_VERSION || SSL_IS_DTLS(s)) {
size_t i;
uint32_t alg_k, alg_a;
STACK_OF(SSL_CIPHER) *cipher_stack = SSL_get_ciphers(s);
for (i = 0; i < sk_SSL_CIPHER_num(cipher_stack); i++) {
const SSL_CIPHER *c = sk_SSL_CIPHER_value(cipher_stack, i);
alg_k = c->algorithm_mkey;
alg_a = c->algorithm_auth;
if ((alg_k & SSL_kECDHE) || (alg_a & SSL_aECDSA)) {
using_ecc = 1;
break;
}
}
}
/* don't add extensions for SSLv3 unless doing secure renegotiation */
if (s->client_version == SSL3_VERSION && !s->s3->send_connection_binding) {
return orig;
}
ret += 2;
if (ret >= limit) {
return NULL; /* should never occur. */
}
s->s3->tmp.extensions.sent = 0;
size_t i;
for (i = 0; i < kNumExtensions; i++) {
if (kExtensions[i].init != NULL) {
kExtensions[i].init(s);
}
}
CBB cbb;
if (!CBB_init_fixed(&cbb, ret, limit - ret)) {
OPENSSL_PUT_ERROR(SSL, ssl_add_clienthello_tlsext, ERR_R_INTERNAL_ERROR);
return NULL;
}
for (i = 0; i < kNumExtensions; i++) {
const size_t space_before = CBB_len(&cbb);
if (!kExtensions[i].add_clienthello(s, &cbb)) {
CBB_cleanup(&cbb);
OPENSSL_PUT_ERROR(SSL, ssl_add_clienthello_tlsext, ERR_R_INTERNAL_ERROR);
return NULL;
}
const size_t space_after = CBB_len(&cbb);
if (space_after != space_before) {
s->s3->tmp.extensions.sent |= (1u << i);
}
}
ret = limit - CBB_len(&cbb);
CBB_cleanup(&cbb);
/* Add extended master secret. */
if (s->version != SSL3_VERSION) {
if (limit - ret - 4 < 0) {
return NULL;
}
s2n(TLSEXT_TYPE_extended_master_secret, ret);
s2n(0, ret);
}
if (!(SSL_get_options(s) & SSL_OP_NO_TICKET)) {
int ticklen = 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 (!s->s3->initial_handshake_complete && s->session != NULL &&
s->session->tlsext_tick != NULL) {
ticklen = s->session->tlsext_ticklen;
}
/* Check for enough room 2 for extension type, 2 for len rest for
* ticket. */
if ((long)(limit - ret - 4 - ticklen) < 0) {
return NULL;
}
s2n(TLSEXT_TYPE_session_ticket, ret);
s2n(ticklen, ret);
if (ticklen) {
memcpy(ret, s->session->tlsext_tick, ticklen);
ret += ticklen;
}
}
if (ssl3_version_from_wire(s, s->client_version) >= TLS1_2_VERSION) {
size_t salglen;
const uint8_t *salg;
salglen = tls12_get_psigalgs(s, &salg);
if ((size_t)(limit - ret) < salglen + 6) {
return NULL;
}
s2n(TLSEXT_TYPE_signature_algorithms, ret);
s2n(salglen + 2, ret);
s2n(salglen, ret);
memcpy(ret, salg, salglen);
ret += salglen;
}
if (s->ocsp_stapling_enabled) {
/* The status_request extension is excessively extensible at every layer.
* On the client, only support requesting OCSP responses with an empty
* responder_id_list and no extensions. */
if (limit - ret - 4 - 1 - 2 - 2 < 0) {
return NULL;
}
s2n(TLSEXT_TYPE_status_request, ret);
s2n(1 + 2 + 2, ret);
/* status_type */
*(ret++) = TLSEXT_STATUSTYPE_ocsp;
/* responder_id_list - empty */
s2n(0, ret);
/* request_extensions - empty */
s2n(0, ret);
}
if (s->ctx->next_proto_select_cb && !s->s3->initial_handshake_complete &&
!SSL_IS_DTLS(s)) {
/* The client advertises an emtpy extension to indicate its support for
* Next Protocol Negotiation */
if (limit - ret - 4 < 0) {
return NULL;
}
s2n(TLSEXT_TYPE_next_proto_neg, ret);
s2n(0, ret);
}
if (s->signed_cert_timestamps_enabled) {
/* The client advertises an empty extension to indicate its support for
* certificate timestamps. */
if (limit - ret - 4 < 0) {
return NULL;
}
s2n(TLSEXT_TYPE_certificate_timestamp, ret);
s2n(0, ret);
}
if (s->alpn_client_proto_list && !s->s3->initial_handshake_complete) {
if ((size_t)(limit - ret) < 6 + s->alpn_client_proto_list_len) {
return NULL;
}
s2n(TLSEXT_TYPE_application_layer_protocol_negotiation, ret);
s2n(2 + s->alpn_client_proto_list_len, ret);
s2n(s->alpn_client_proto_list_len, ret);
memcpy(ret, s->alpn_client_proto_list, s->alpn_client_proto_list_len);
ret += s->alpn_client_proto_list_len;
}
if (s->tlsext_channel_id_enabled && !SSL_IS_DTLS(s)) {
/* The client advertises an emtpy extension to indicate its support for
* Channel ID. */
if (limit - ret - 4 < 0) {
return NULL;
}
if (s->ctx->tlsext_channel_id_enabled_new) {
s2n(TLSEXT_TYPE_channel_id_new, ret);
} else {
s2n(TLSEXT_TYPE_channel_id, ret);
}
s2n(0, ret);
}
if (SSL_get_srtp_profiles(s)) {
int el;
ssl_add_clienthello_use_srtp_ext(s, 0, &el, 0);
if ((limit - ret - 4 - el) < 0) {
return NULL;
}
s2n(TLSEXT_TYPE_use_srtp, ret);
s2n(el, ret);
if (!ssl_add_clienthello_use_srtp_ext(s, ret, &el, el)) {
OPENSSL_PUT_ERROR(SSL, ssl_add_clienthello_tlsext, ERR_R_INTERNAL_ERROR);
return NULL;
}
ret += el;
}
if (using_ecc) {
/* Add TLS extension ECPointFormats to the ClientHello message */
long lenmax;
const uint8_t *formats;
const uint16_t *curves;
size_t formats_len, curves_len;
tls1_get_formatlist(s, &formats, &formats_len);
lenmax = limit - ret - 5;
if (lenmax < 0) {
return NULL;
}
if (formats_len > (size_t)lenmax) {
return NULL;
}
if (formats_len > 255) {
OPENSSL_PUT_ERROR(SSL, ssl_add_clienthello_tlsext, ERR_R_INTERNAL_ERROR);
return NULL;
}
s2n(TLSEXT_TYPE_ec_point_formats, ret);
s2n(formats_len + 1, ret);
*(ret++) = (uint8_t)formats_len;
memcpy(ret, formats, formats_len);
ret += formats_len;
/* Add TLS extension EllipticCurves to the ClientHello message */
tls1_get_curvelist(s, 0, &curves, &curves_len);
lenmax = limit - ret - 6;
if (lenmax < 0) {
return NULL;
}
if (curves_len * 2 > (size_t)lenmax) {
return NULL;
}
if (curves_len * 2 > 65532) {
OPENSSL_PUT_ERROR(SSL, ssl_add_clienthello_tlsext, ERR_R_INTERNAL_ERROR);
return NULL;
}
s2n(TLSEXT_TYPE_elliptic_curves, ret);
s2n((curves_len * 2) + 2, ret);
s2n(curves_len * 2, ret);
for (i = 0; i < curves_len; i++) {
s2n(curves[i], ret);
}
}
if (header_len > 0) {
size_t clienthello_minsize = 0;
header_len += ret - orig;
if (header_len > 0xff && header_len < 0x200) {
/* Add padding to workaround bugs in F5 terminators. See
* https://tools.ietf.org/html/draft-agl-tls-padding-03
*
* NB: because this code works out the length of all existing extensions
* it MUST always appear last. */
clienthello_minsize = 0x200;
}
if (s->fastradio_padding) {
/* Pad the ClientHello record to 1024 bytes to fast forward the radio
* into DCH (high data rate) state in 3G networks. Note that when
* fastradio_padding is enabled, even if the header_len is less than 255
* bytes, the padding will be applied regardless. This is slightly
* different from the TLS padding extension suggested in
* https://tools.ietf.org/html/draft-agl-tls-padding-03 */
clienthello_minsize = 0x400;
}
if (header_len < clienthello_minsize) {
size_t padding_len = clienthello_minsize - header_len;
/* Extensions take at least four bytes to encode. Always include least
* one byte of data if including the extension. WebSphere Application
* Server 7.0 is intolerant to the last extension being zero-length. */
if (padding_len >= 4 + 1) {
padding_len -= 4;
} else {
padding_len = 1;
}
if (limit - ret - 4 - (long)padding_len < 0) {
return NULL;
}
s2n(TLSEXT_TYPE_padding, ret);
s2n(padding_len, ret);
memset(ret, 0, padding_len);
ret += padding_len;
}
}
extdatalen = ret - orig - 2;
if (extdatalen == 0) {
return orig;
}
s2n(extdatalen, orig);
return ret;
}
uint8_t *ssl_add_serverhello_tlsext(SSL *s, uint8_t *const buf,
uint8_t *const limit) {
int extdatalen = 0;
uint8_t *orig = buf;
uint8_t *ret = buf;
int next_proto_neg_seen;
uint32_t alg_k = s->s3->tmp.new_cipher->algorithm_mkey;
uint32_t alg_a = s->s3->tmp.new_cipher->algorithm_auth;
int using_ecc = (alg_k & SSL_kECDHE) || (alg_a & SSL_aECDSA);
using_ecc = using_ecc && (s->s3->tmp.peer_ecpointformatlist != NULL);
/* don't add extensions for SSLv3, unless doing secure renegotiation */
if (s->version == SSL3_VERSION && !s->s3->send_connection_binding) {
return orig;
}
ret += 2;
if (ret >= limit) {
return NULL; /* should never happen. */
}
CBB cbb;
if (!CBB_init_fixed(&cbb, ret, limit - ret)) {
OPENSSL_PUT_ERROR(SSL, ssl_add_serverhello_tlsext, ERR_R_INTERNAL_ERROR);
return NULL;
}
unsigned i;
for (i = 0; i < kNumExtensions; i++) {
if (!(s->s3->tmp.extensions.received & (1u << i))) {
/* Don't send extensions that were not received. */
continue;
}
if (!kExtensions[i].add_serverhello(s, &cbb)) {
CBB_cleanup(&cbb);
OPENSSL_PUT_ERROR(SSL, ssl_add_serverhello_tlsext, ERR_R_INTERNAL_ERROR);
return NULL;
}
}
ret = limit - CBB_len(&cbb);
CBB_cleanup(&cbb);
if (s->s3->tmp.extended_master_secret) {
if ((long)(limit - ret - 4) < 0) {
return NULL;
}
s2n(TLSEXT_TYPE_extended_master_secret, ret);
s2n(0, ret);
}
if (using_ecc) {
const uint8_t *plist;
size_t plistlen;
/* Add TLS extension ECPointFormats to the ServerHello message */
long lenmax;
tls1_get_formatlist(s, &plist, &plistlen);
lenmax = limit - ret - 5;
if (lenmax < 0) {
return NULL;
}
if (plistlen > (size_t)lenmax) {
return NULL;
}
if (plistlen > 255) {
OPENSSL_PUT_ERROR(SSL, ssl_add_serverhello_tlsext, ERR_R_INTERNAL_ERROR);
return NULL;
}
s2n(TLSEXT_TYPE_ec_point_formats, ret);
s2n(plistlen + 1, ret);
*(ret++) = (uint8_t)plistlen;
memcpy(ret, plist, plistlen);
ret += plistlen;
}
/* Currently the server should not respond with a SupportedCurves extension */
if (s->tlsext_ticket_expected && !(SSL_get_options(s) & SSL_OP_NO_TICKET)) {
if ((long)(limit - ret - 4) < 0) {
return NULL;
}
s2n(TLSEXT_TYPE_session_ticket, ret);
s2n(0, ret);
}
if (s->s3->tmp.certificate_status_expected) {
if ((long)(limit - ret - 4) < 0) {
return NULL;
}
s2n(TLSEXT_TYPE_status_request, ret);
s2n(0, ret);
}
if (s->srtp_profile) {
int el;
ssl_add_serverhello_use_srtp_ext(s, 0, &el, 0);
if ((limit - ret - 4 - el) < 0) {
return NULL;
}
s2n(TLSEXT_TYPE_use_srtp, ret);
s2n(el, ret);
if (!ssl_add_serverhello_use_srtp_ext(s, ret, &el, el)) {
OPENSSL_PUT_ERROR(SSL, ssl_add_serverhello_tlsext, ERR_R_INTERNAL_ERROR);
return NULL;
}
ret += el;
}
next_proto_neg_seen = s->s3->next_proto_neg_seen;
s->s3->next_proto_neg_seen = 0;
if (next_proto_neg_seen && s->ctx->next_protos_advertised_cb) {
const uint8_t *npa;
unsigned int npalen;
int r;
r = s->ctx->next_protos_advertised_cb(
s, &npa, &npalen, s->ctx->next_protos_advertised_cb_arg);
if (r == SSL_TLSEXT_ERR_OK) {
if ((long)(limit - ret - 4 - npalen) < 0) {
return NULL;
}
s2n(TLSEXT_TYPE_next_proto_neg, ret);
s2n(npalen, ret);
memcpy(ret, npa, npalen);
ret += npalen;
s->s3->next_proto_neg_seen = 1;
}
}
if (s->s3->alpn_selected) {
const uint8_t *selected = s->s3->alpn_selected;
size_t len = s->s3->alpn_selected_len;
if ((long)(limit - ret - 4 - 2 - 1 - len) < 0) {
return NULL;
}
s2n(TLSEXT_TYPE_application_layer_protocol_negotiation, ret);
s2n(3 + len, ret);
s2n(1 + len, ret);
*ret++ = len;
memcpy(ret, selected, len);
ret += len;
}
/* If the client advertised support for Channel ID, and we have it
* enabled, then we want to echo it back. */
if (s->s3->tlsext_channel_id_valid) {
if (limit - ret - 4 < 0) {
return NULL;
}
if (s->s3->tlsext_channel_id_new) {
s2n(TLSEXT_TYPE_channel_id_new, ret);
} else {
s2n(TLSEXT_TYPE_channel_id, ret);
}
s2n(0, ret);
}
extdatalen = ret - orig - 2;
if (extdatalen == 0) {
return orig;
}
s2n(extdatalen, orig);
return ret;
}
/* tls1_alpn_handle_client_hello is called to process the ALPN extension in a
* ClientHello.
* cbs: the contents of the extension, not including the type and length.
* out_alert: a pointer to the alert value to send in the event of a zero
* return.
*
* returns: 1 on success. */
static int tls1_alpn_handle_client_hello(SSL *s, CBS *cbs, int *out_alert) {
CBS protocol_name_list, protocol_name_list_copy;
const uint8_t *selected;
uint8_t selected_len;
int r;
if (s->ctx->alpn_select_cb == NULL) {
return 1;
}
if (!CBS_get_u16_length_prefixed(cbs, &protocol_name_list) ||
CBS_len(cbs) != 0 || CBS_len(&protocol_name_list) < 2) {
goto parse_error;
}
/* Validate the protocol list. */
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)) {
goto parse_error;
}
}
r = s->ctx->alpn_select_cb(
s, &selected, &selected_len, CBS_data(&protocol_name_list),
CBS_len(&protocol_name_list), s->ctx->alpn_select_cb_arg);
if (r == SSL_TLSEXT_ERR_OK) {
OPENSSL_free(s->s3->alpn_selected);
s->s3->alpn_selected = BUF_memdup(selected, selected_len);
if (!s->s3->alpn_selected) {
*out_alert = SSL_AD_INTERNAL_ERROR;
return 0;
}
s->s3->alpn_selected_len = selected_len;
}
return 1;
parse_error:
*out_alert = SSL_AD_DECODE_ERROR;
return 0;
}
static int ssl_scan_clienthello_tlsext(SSL *s, CBS *cbs, int *out_alert) {
CBS extensions;
s->srtp_profile = NULL;
s->s3->next_proto_neg_seen = 0;
s->s3->tmp.certificate_status_expected = 0;
s->s3->tmp.extended_master_secret = 0;
OPENSSL_free(s->s3->alpn_selected);
s->s3->alpn_selected = NULL;
/* Clear any signature algorithms extension received */
OPENSSL_free(s->cert->peer_sigalgs);
s->cert->peer_sigalgs = NULL;
s->cert->peer_sigalgslen = 0;
/* Clear any shared signature algorithms */
OPENSSL_free(s->cert->shared_sigalgs);
s->cert->shared_sigalgs = NULL;
s->cert->shared_sigalgslen = 0;
/* Clear ECC extensions */
OPENSSL_free(s->s3->tmp.peer_ecpointformatlist);
s->s3->tmp.peer_ecpointformatlist = NULL;
s->s3->tmp.peer_ecpointformatlist_length = 0;
OPENSSL_free(s->s3->tmp.peer_ellipticcurvelist);
s->s3->tmp.peer_ellipticcurvelist = NULL;
s->s3->tmp.peer_ellipticcurvelist_length = 0;
size_t i;
for (i = 0; i < kNumExtensions; i++) {
if (kExtensions[i].init != NULL) {
kExtensions[i].init(s);
}
}
s->s3->tmp.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) {
goto no_extensions;
}
/* Decode the extensions block and check it is valid. */
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) {
s->s3->tmp.extensions.received |= (1u << ext_index);
uint8_t alert = SSL_AD_DECODE_ERROR;
if (!ext->parse_clienthello(s, &alert, &extension)) {
*out_alert = alert;
return 0;
}
continue;
}
if (type == TLSEXT_TYPE_ec_point_formats) {
CBS ec_point_format_list;
if (!CBS_get_u8_length_prefixed(&extension, &ec_point_format_list) ||
CBS_len(&extension) != 0) {
*out_alert = SSL_AD_DECODE_ERROR;
return 0;
}
if (!CBS_stow(&ec_point_format_list, &s->s3->tmp.peer_ecpointformatlist,
&s->s3->tmp.peer_ecpointformatlist_length)) {
*out_alert = SSL_AD_INTERNAL_ERROR;
return 0;
}
} else if (type == TLSEXT_TYPE_elliptic_curves) {
CBS elliptic_curve_list;
size_t num_curves;
if (!CBS_get_u16_length_prefixed(&extension, &elliptic_curve_list) ||
CBS_len(&elliptic_curve_list) == 0 ||
(CBS_len(&elliptic_curve_list) & 1) != 0 ||
CBS_len(&extension) != 0) {
*out_alert = SSL_AD_DECODE_ERROR;
return 0;
}
OPENSSL_free(s->s3->tmp.peer_ellipticcurvelist);
s->s3->tmp.peer_ellipticcurvelist_length = 0;
s->s3->tmp.peer_ellipticcurvelist =
(uint16_t *)OPENSSL_malloc(CBS_len(&elliptic_curve_list));
if (s->s3->tmp.peer_ellipticcurvelist == NULL) {
*out_alert = SSL_AD_INTERNAL_ERROR;
return 0;
}
num_curves = CBS_len(&elliptic_curve_list) / 2;
for (i = 0; i < num_curves; i++) {
if (!CBS_get_u16(&elliptic_curve_list,
&s->s3->tmp.peer_ellipticcurvelist[i])) {
*out_alert = SSL_AD_INTERNAL_ERROR;
return 0;
}
}
if (CBS_len(&elliptic_curve_list) != 0) {
*out_alert = SSL_AD_INTERNAL_ERROR;
return 0;
}
s->s3->tmp.peer_ellipticcurvelist_length = num_curves;
} else if (type == TLSEXT_TYPE_signature_algorithms) {
CBS supported_signature_algorithms;
if (!CBS_get_u16_length_prefixed(&extension,
&supported_signature_algorithms) ||
CBS_len(&extension) != 0) {
*out_alert = SSL_AD_DECODE_ERROR;
return 0;
}
/* Ensure the signature algorithms are non-empty. It contains a list of
* SignatureAndHashAlgorithms which are two bytes each. */
if (CBS_len(&supported_signature_algorithms) == 0 ||
(CBS_len(&supported_signature_algorithms) % 2) != 0) {
*out_alert = SSL_AD_DECODE_ERROR;
return 0;
}
if (!tls1_process_sigalgs(s, &supported_signature_algorithms)) {
*out_alert = SSL_AD_DECODE_ERROR;
return 0;
}
/* If sigalgs received and no shared algorithms fatal error. */
if (s->cert->peer_sigalgs && !s->cert->shared_sigalgs) {
OPENSSL_PUT_ERROR(SSL, ssl_scan_clienthello_tlsext,
SSL_R_NO_SHARED_SIGATURE_ALGORITHMS);
*out_alert = SSL_AD_ILLEGAL_PARAMETER;
return 0;
}
} else if (type == TLSEXT_TYPE_next_proto_neg &&
!s->s3->initial_handshake_complete &&
s->s3->alpn_selected == NULL && !SSL_IS_DTLS(s)) {
/* The extension must be empty. */
if (CBS_len(&extension) != 0) {
*out_alert = SSL_AD_DECODE_ERROR;
return 0;
}
s->s3->next_proto_neg_seen = 1;
} else if (type == TLSEXT_TYPE_application_layer_protocol_negotiation &&
s->ctx->alpn_select_cb && !s->s3->initial_handshake_complete) {
if (!tls1_alpn_handle_client_hello(s, &extension, out_alert)) {
return 0;
}
/* ALPN takes precedence over NPN. */
s->s3->next_proto_neg_seen = 0;
} else if (type == TLSEXT_TYPE_channel_id && s->tlsext_channel_id_enabled &&
!SSL_IS_DTLS(s)) {
/* The extension must be empty. */
if (CBS_len(&extension) != 0) {
*out_alert = SSL_AD_DECODE_ERROR;
return 0;
}
s->s3->tlsext_channel_id_valid = 1;
} else if (type == TLSEXT_TYPE_channel_id_new &&
s->tlsext_channel_id_enabled && !SSL_IS_DTLS(s)) {
/* The extension must be empty. */
if (CBS_len(&extension) != 0) {
*out_alert = SSL_AD_DECODE_ERROR;
return 0;
}
s->s3->tlsext_channel_id_valid = 1;
s->s3->tlsext_channel_id_new = 1;
} else if (type == TLSEXT_TYPE_use_srtp) {
if (!ssl_parse_clienthello_use_srtp_ext(s, &extension, out_alert)) {
return 0;
}
} else if (type == TLSEXT_TYPE_extended_master_secret &&
s->version != SSL3_VERSION) {
if (CBS_len(&extension) != 0) {
*out_alert = SSL_AD_DECODE_ERROR;
return 0;
}
s->s3->tmp.extended_master_secret = 1;
}
}
no_extensions:
for (i = 0; i < kNumExtensions; i++) {
if (!(s->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(s, &alert, NULL)) {
*out_alert = alert;
return 0;
}
}
}
return 1;
}
int ssl_parse_clienthello_tlsext(SSL *s, CBS *cbs) {
int alert = -1;
if (ssl_scan_clienthello_tlsext(s, cbs, &alert) <= 0) {
ssl3_send_alert(s, SSL3_AL_FATAL, alert);
return 0;
}
if (ssl_check_clienthello_tlsext(s) <= 0) {
OPENSSL_PUT_ERROR(SSL, ssl_parse_clienthello_tlsext,
SSL_R_CLIENTHELLO_TLSEXT);
return 0;
}
return 1;
}
/* ssl_next_proto_validate validates a Next Protocol Negotiation block. No
* elements of zero length are allowed and the set of elements must exactly
* fill the length of the block. */
static char ssl_next_proto_validate(const CBS *cbs) {
CBS copy = *cbs;
while (CBS_len(&copy) != 0) {
CBS proto;
if (!CBS_get_u8_length_prefixed(&copy, &proto) || CBS_len(&proto) == 0) {
return 0;
}
}
return 1;
}
static int ssl_scan_serverhello_tlsext(SSL *s, CBS *cbs, int *out_alert) {
CBS extensions;
/* TODO(davidben): Move all of these to some per-handshake state that gets
* systematically reset on a new handshake; perhaps allocate it fresh each
* time so it's not even kept around post-handshake. */
s->s3->next_proto_neg_seen = 0;
s->tlsext_ticket_expected = 0;
s->s3->tmp.certificate_status_expected = 0;
s->s3->tmp.extended_master_secret = 0;
s->srtp_profile = NULL;
OPENSSL_free(s->s3->alpn_selected);
s->s3->alpn_selected = NULL;
/* Clear ECC extensions */
OPENSSL_free(s->s3->tmp.peer_ecpointformatlist);
s->s3->tmp.peer_ecpointformatlist = NULL;
s->s3->tmp.peer_ecpointformatlist_length = 0;
uint32_t received = 0;
size_t i;
assert(kNumExtensions <= sizeof(received) * 8);
/* There may be no extensions. */
if (CBS_len(cbs) == 0) {
goto no_extensions;
}
/* Decode the extensions block and check it is valid. */
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);
/* While we have extensions that don't use tls_extension this conditional
* needs to be guarded on |ext != NULL|. In the future, ext being NULL will
* be fatal. */
if (ext != NULL) {
if (!(s->s3->tmp.extensions.sent & (1u << ext_index))) {
/* Received an extension that was never sent. */
OPENSSL_PUT_ERROR(SSL, ssl_scan_serverhello_tlsext,
SSL_R_UNEXPECTED_EXTENSION);
ERR_add_error_dataf("ext:%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(s, &alert, &extension)) {
*out_alert = alert;
return 0;
}
continue;
}
if (type == TLSEXT_TYPE_ec_point_formats) {
CBS ec_point_format_list;
if (!CBS_get_u8_length_prefixed(&extension, &ec_point_format_list) ||
CBS_len(&extension) != 0) {
*out_alert = SSL_AD_DECODE_ERROR;
return 0;
}
if (!CBS_stow(&ec_point_format_list, &s->s3->tmp.peer_ecpointformatlist,
&s->s3->tmp.peer_ecpointformatlist_length)) {
*out_alert = SSL_AD_INTERNAL_ERROR;
return 0;
}
} else if (type == TLSEXT_TYPE_session_ticket) {
if ((SSL_get_options(s) & SSL_OP_NO_TICKET) || CBS_len(&extension) > 0) {
*out_alert = SSL_AD_UNSUPPORTED_EXTENSION;
return 0;
}
s->tlsext_ticket_expected = 1;
} else if (type == TLSEXT_TYPE_status_request) {
/* The extension MUST be empty and may only sent if we've requested a
* status request message. */
if (CBS_len(&extension) != 0) {
*out_alert = SSL_AD_DECODE_ERROR;
return 0;
}
if (!s->ocsp_stapling_enabled) {
*out_alert = SSL_AD_UNSUPPORTED_EXTENSION;
return 0;
}
/* Set a flag to expect a CertificateStatus message */
s->s3->tmp.certificate_status_expected = 1;
} else if (type == TLSEXT_TYPE_next_proto_neg &&
!s->s3->initial_handshake_complete && !SSL_IS_DTLS(s)) {
uint8_t *selected;
uint8_t selected_len;
/* We must have requested it. */
if (s->ctx->next_proto_select_cb == NULL) {
*out_alert = SSL_AD_UNSUPPORTED_EXTENSION;
return 0;
}
/* The data must be valid. */
if (!ssl_next_proto_validate(&extension)) {
*out_alert = SSL_AD_DECODE_ERROR;
return 0;
}
if (s->ctx->next_proto_select_cb(
s, &selected, &selected_len, CBS_data(&extension),
CBS_len(&extension),
s->ctx->next_proto_select_cb_arg) != SSL_TLSEXT_ERR_OK) {
*out_alert = SSL_AD_INTERNAL_ERROR;
return 0;
}
s->next_proto_negotiated = BUF_memdup(selected, selected_len);
if (s->next_proto_negotiated == NULL) {
*out_alert = SSL_AD_INTERNAL_ERROR;
return 0;
}
s->next_proto_negotiated_len = selected_len;
s->s3->next_proto_neg_seen = 1;
} else if (type == TLSEXT_TYPE_application_layer_protocol_negotiation &&
!s->s3->initial_handshake_complete) {
CBS protocol_name_list, protocol_name;
/* We must have requested it. */
if (s->alpn_client_proto_list == NULL) {
*out_alert = SSL_AD_UNSUPPORTED_EXTENSION;
return 0;
}
/* The extension data consists of a ProtocolNameList which must have
* exactly one ProtocolName. Each of these is length-prefixed. */
if (!CBS_get_u16_length_prefixed(&extension, &protocol_name_list) ||
CBS_len(&extension) != 0 ||
!CBS_get_u8_length_prefixed(&protocol_name_list, &protocol_name) ||
CBS_len(&protocol_name_list) != 0) {
*out_alert = SSL_AD_DECODE_ERROR;
return 0;
}
if (!CBS_stow(&protocol_name, &s->s3->alpn_selected,
&s->s3->alpn_selected_len)) {
*out_alert = SSL_AD_INTERNAL_ERROR;
return 0;
}
} else if (type == TLSEXT_TYPE_channel_id && !SSL_IS_DTLS(s)) {
if (CBS_len(&extension) != 0) {
*out_alert = SSL_AD_DECODE_ERROR;
return 0;
}
s->s3->tlsext_channel_id_valid = 1;
} else if (type == TLSEXT_TYPE_channel_id_new && !SSL_IS_DTLS(s)) {
if (CBS_len(&extension) != 0) {
*out_alert = SSL_AD_DECODE_ERROR;
return 0;
}
s->s3->tlsext_channel_id_valid = 1;
s->s3->tlsext_channel_id_new = 1;
} else if (type == TLSEXT_TYPE_certificate_timestamp) {
if (CBS_len(&extension) == 0) {
*out_alert = SSL_AD_DECODE_ERROR;
return 0;
}
/* Session resumption uses the original session information. */
if (!s->hit &&
!CBS_stow(&extension, &s->session->tlsext_signed_cert_timestamp_list,
&s->session->tlsext_signed_cert_timestamp_list_length)) {
*out_alert = SSL_AD_INTERNAL_ERROR;
return 0;
}
} else if (type == TLSEXT_TYPE_use_srtp) {
if (!ssl_parse_serverhello_use_srtp_ext(s, &extension, out_alert)) {
return 0;
}
} else if (type == TLSEXT_TYPE_extended_master_secret) {
if (/* It is invalid for the server to select EMS and
SSLv3. */
s->version == SSL3_VERSION || CBS_len(&extension) != 0) {
*out_alert = SSL_AD_DECODE_ERROR;
return 0;
}
s->s3->tmp.extended_master_secret = 1;
}
}
no_extensions:
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(s, &alert, NULL)) {
*out_alert = alert;
return 0;
}
}
}
return 1;
}
int ssl_prepare_clienthello_tlsext(SSL *s) { return 1; }
int ssl_prepare_serverhello_tlsext(SSL *s) { return 1; }
static int ssl_check_clienthello_tlsext(SSL *s) {
int ret = SSL_TLSEXT_ERR_NOACK;
int al = SSL_AD_UNRECOGNIZED_NAME;
/* The handling of the ECPointFormats extension is done elsewhere, namely in
* ssl3_choose_cipher in s3_lib.c. */
if (s->ctx != NULL && s->ctx->tlsext_servername_callback != 0) {
ret = s->ctx->tlsext_servername_callback(s, &al,
s->ctx->tlsext_servername_arg);
} else if (s->initial_ctx != NULL &&
s->initial_ctx->tlsext_servername_callback != 0) {
ret = s->initial_ctx->tlsext_servername_callback(
s, &al, s->initial_ctx->tlsext_servername_arg);
}
switch (ret) {
case SSL_TLSEXT_ERR_ALERT_FATAL:
ssl3_send_alert(s, SSL3_AL_FATAL, al);
return -1;
case SSL_TLSEXT_ERR_ALERT_WARNING:
ssl3_send_alert(s, SSL3_AL_WARNING, al);
return 1;
case SSL_TLSEXT_ERR_NOACK:
s->s3->tmp.should_ack_sni = 0;
return 1;
default:
return 1;
}
}
static int ssl_check_serverhello_tlsext(SSL *s) {
int ret = SSL_TLSEXT_ERR_NOACK;
int al = SSL_AD_UNRECOGNIZED_NAME;
/* If we are client and using an elliptic curve cryptography cipher suite,
* then if server returns an EC point formats lists extension it must contain
* uncompressed. */
uint32_t alg_k = s->s3->tmp.new_cipher->algorithm_mkey;
uint32_t alg_a = s->s3->tmp.new_cipher->algorithm_auth;
if (((alg_k & SSL_kECDHE) || (alg_a & SSL_aECDSA)) &&
!tls1_check_point_format(s, TLSEXT_ECPOINTFORMAT_uncompressed)) {
OPENSSL_PUT_ERROR(SSL, ssl_check_serverhello_tlsext,
SSL_R_TLS_INVALID_ECPOINTFORMAT_LIST);
return -1;
}
ret = SSL_TLSEXT_ERR_OK;
if (s->ctx != NULL && s->ctx->tlsext_servername_callback != 0) {
ret = s->ctx->tlsext_servername_callback(s, &al,
s->ctx->tlsext_servername_arg);
} else if (s->initial_ctx != NULL &&
s->initial_ctx->tlsext_servername_callback != 0) {
ret = s->initial_ctx->tlsext_servername_callback(
s, &al, s->initial_ctx->tlsext_servername_arg);
}
switch (ret) {
case SSL_TLSEXT_ERR_ALERT_FATAL:
ssl3_send_alert(s, SSL3_AL_FATAL, al);
return -1;
case SSL_TLSEXT_ERR_ALERT_WARNING:
ssl3_send_alert(s, SSL3_AL_WARNING, al);
return 1;
default:
return 1;
}
}
int ssl_parse_serverhello_tlsext(SSL *s, CBS *cbs) {
int alert = -1;
if (s->version < SSL3_VERSION) {
return 1;
}
if (ssl_scan_serverhello_tlsext(s, cbs, &alert) <= 0) {
ssl3_send_alert(s, SSL3_AL_FATAL, alert);
return 0;
}
if (ssl_check_serverhello_tlsext(s) <= 0) {
OPENSSL_PUT_ERROR(SSL, ssl_parse_serverhello_tlsext,
SSL_R_SERVERHELLO_TLSEXT);
return 0;
}
return 1;
}
int tls_process_ticket(SSL *ssl, SSL_SESSION **out_session,
int *out_send_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_send_ticket = 0;
*out_session = NULL;
if (session_id_len > SSL_MAX_SSL_SESSION_ID_LENGTH) {
goto done;
}
if (ticket_len == 0) {
/* The client will accept a ticket but doesn't currently have one. */
*out_send_ticket = 1;
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_send_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_md5, TLSEXT_hash_md5},
{NID_sha1, TLSEXT_hash_sha1},
{NID_sha224, TLSEXT_hash_sha224},
{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_get_sigandhash(SSL *ssl, uint8_t *p, const EVP_PKEY *pk,
const EVP_MD *md) {
int sig_id, md_id;
if (!md) {
return 0;
}
md_id = tls12_find_id(EVP_MD_type(md), tls12_md,
sizeof(tls12_md) / sizeof(tls12_lookup));
if (md_id == -1) {
return 0;
}
sig_id = tls12_get_sigid(ssl_private_key_type(ssl, pk));
if (sig_id == -1) {
return 0;
}
p[0] = (uint8_t)md_id;
p[1] = (uint8_t)sig_id;
return 1;
}
const EVP_MD *tls12_get_hash(uint8_t hash_alg) {
switch (hash_alg) {
case TLSEXT_hash_md5:
return EVP_md5();
case TLSEXT_hash_sha1:
return EVP_sha1();
case TLSEXT_hash_sha224:
return EVP_sha224();
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;
}
}
/* Given preference and allowed sigalgs set shared sigalgs */
static int tls12_do_shared_sigalgs(TLS_SIGALGS *shsig, const uint8_t *pref,
size_t preflen, const uint8_t *allow,
size_t allowlen) {
const uint8_t *ptmp, *atmp;
size_t i, j, nmatch = 0;
for (i = 0, ptmp = pref; i < preflen; i += 2, ptmp += 2) {
/* Skip disabled hashes or signature algorithms */
if (tls12_get_hash(ptmp[0]) == NULL ||
tls12_get_pkey_type(ptmp[1]) == -1) {
continue;
}
for (j = 0, atmp = allow; j < allowlen; j += 2, atmp += 2) {
if (ptmp[0] == atmp[0] && ptmp[1] == atmp[1]) {
nmatch++;
if (shsig) {
shsig->rhash = ptmp[0];
shsig->rsign = ptmp[1];
shsig++;
}
break;
}
}
}
return nmatch;
}
/* Set shared signature algorithms for SSL structures */
static int tls1_set_shared_sigalgs(SSL *s) {
const uint8_t *pref, *allow, *conf;
size_t preflen, allowlen, conflen;
size_t nmatch;
TLS_SIGALGS *salgs = NULL;
CERT *c = s->cert;
OPENSSL_free(c->shared_sigalgs);
c->shared_sigalgs = NULL;
c->shared_sigalgslen = 0;
/* If client use client signature algorithms if not NULL */
if (!s->server && c->client_sigalgs) {
conf = c->client_sigalgs;
conflen = c->client_sigalgslen;
} else if (c->conf_sigalgs) {
conf = c->conf_sigalgs;
conflen = c->conf_sigalgslen;
} else {
conflen = tls12_get_psigalgs(s, &conf);
}
if (s->options & SSL_OP_CIPHER_SERVER_PREFERENCE) {
pref = conf;
preflen = conflen;
allow = c->peer_sigalgs;
allowlen = c->peer_sigalgslen;
} else {
allow = conf;
allowlen = conflen;
pref = c->peer_sigalgs;
preflen = c->peer_sigalgslen;
}
nmatch = tls12_do_shared_sigalgs(NULL, pref, preflen, allow, allowlen);
if (!nmatch) {
return 1;
}
salgs = OPENSSL_malloc(nmatch * sizeof(TLS_SIGALGS));
if (!salgs) {
return 0;
}
nmatch = tls12_do_shared_sigalgs(salgs, pref, preflen, allow, allowlen);
c->shared_sigalgs = salgs;
c->shared_sigalgslen = nmatch;
return 1;
}
/* Set preferred digest for each key type */
int tls1_process_sigalgs(SSL *s, const CBS *sigalgs) {
CERT *c = s->cert;
/* Extension ignored for inappropriate versions */
if (!SSL_USE_SIGALGS(s)) {
return 1;
}
if (CBS_len(sigalgs) % 2 != 0 ||
!CBS_stow(sigalgs, &c->peer_sigalgs, &c->peer_sigalgslen) ||
!tls1_set_shared_sigalgs(s)) {
return 0;
}
return 1;
}
const EVP_MD *tls1_choose_signing_digest(SSL *s, EVP_PKEY *pkey) {
CERT *c = s->cert;
int type = ssl_private_key_type(s, pkey);
size_t i;
/* Select the first shared digest supported by our key. */
for (i = 0; i < c->shared_sigalgslen; i++) {
const EVP_MD *md = tls12_get_hash(c->shared_sigalgs[i].rhash);
if (md == NULL ||
tls12_get_pkey_type(c->shared_sigalgs[i].rsign) != type ||
!ssl_private_key_supports_digest(s, pkey, md)) {
continue;
}
return md;
}
/* If no suitable digest may be found, default to SHA-1. */
return EVP_sha1();
}
/* tls1_channel_id_hash calculates the signed data for a Channel ID on the
* given SSL connection and writes it to |md|. */
int tls1_channel_id_hash(EVP_MD_CTX *md, SSL *s) {
EVP_MD_CTX ctx;
uint8_t temp_digest[EVP_MAX_MD_SIZE];
unsigned temp_digest_len;
int i;
static const char kClientIDMagic[] = "TLS Channel ID signature";
if (s->s3->handshake_buffer &&
!ssl3_digest_cached_records(s, free_handshake_buffer)) {
return 0;
}
EVP_DigestUpdate(md, kClientIDMagic, sizeof(kClientIDMagic));
if (s->hit && s->s3->tlsext_channel_id_new) {
static const char kResumptionMagic[] = "Resumption";
EVP_DigestUpdate(md, kResumptionMagic, sizeof(kResumptionMagic));
if (s->session->original_handshake_hash_len == 0) {
return 0;
}
EVP_DigestUpdate(md, s->session->original_handshake_hash,
s->session->original_handshake_hash_len);
}
EVP_MD_CTX_init(&ctx);
for (i = 0; i < SSL_MAX_DIGEST; i++) {
if (s->s3->handshake_dgst[i] == NULL) {
continue;
}
if (!EVP_MD_CTX_copy_ex(&ctx, s->s3->handshake_dgst[i])) {
EVP_MD_CTX_cleanup(&ctx);
return 0;
}
EVP_DigestFinal_ex(&ctx, temp_digest, &temp_digest_len);
EVP_DigestUpdate(md, temp_digest, temp_digest_len);
}
EVP_MD_CTX_cleanup(&ctx);
return 1;
}
/* tls1_record_handshake_hashes_for_channel_id records the current handshake
* hashes in |s->session| so that Channel ID resumptions can sign that data. */
int tls1_record_handshake_hashes_for_channel_id(SSL *s) {
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 (s->hit) {
return -1;
}
/* It only makes sense to call this function if Channel IDs have been
* negotiated. */
if (!s->s3->tlsext_channel_id_new) {
return -1;
}
digest_len =
tls1_handshake_digest(s, s->session->original_handshake_hash,
sizeof(s->session->original_handshake_hash));
if (digest_len < 0) {
return -1;
}
s->session->original_handshake_hash_len = digest_len;
return 1;
}
int tls1_set_sigalgs(CERT *c, const int *psig_nids, size_t salglen,
int client) {
uint8_t *sigalgs, *sptr;
int rhash, rsign;
size_t i;
if (salglen & 1) {
return 0;
}
sigalgs = OPENSSL_malloc(salglen);
if (sigalgs == NULL) {
return 0;
}
for (i = 0, sptr = sigalgs; i < salglen; i += 2) {
rhash = tls12_find_id(*psig_nids++, tls12_md,
sizeof(tls12_md) / sizeof(tls12_lookup));
rsign = tls12_find_id(*psig_nids++, tls12_sig,
sizeof(tls12_sig) / sizeof(tls12_lookup));
if (rhash == -1 || rsign == -1) {
goto err;
}
*sptr++ = rhash;
*sptr++ = rsign;
}
if (client) {
OPENSSL_free(c->client_sigalgs);
c->client_sigalgs = sigalgs;
c->client_sigalgslen = salglen;
} else {
OPENSSL_free(c->conf_sigalgs);
c->conf_sigalgs = sigalgs;
c->conf_sigalgslen = salglen;
}
return 1;
err:
OPENSSL_free(sigalgs);
return 0;
}
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