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c642aca28f
boringssl/ssl/handshake_server.cc
David Benjamin c642aca28f Convert SSL_ECDH_CTX to C++. 
SSLECDHContext has the acronyms problem, so I went with SSLKeyShare to
match the TLS 1.3 terminology. It's also a little shorter. Accept and
Finish, for now, take raw output pointers in anticipation of some
bssl::Array and maybe bssl::CleansedArray types.

Bug: 132
Change-Id: I427c7c0eac95704f3ad093676c504c2848f5acb9
Reviewed-on: https://boringssl-review.googlesource.com/18265
Reviewed-by: Steven Valdez <svaldez@google.com>
2017-07-20 21:27:23 +00:00

1722 lines
56 KiB
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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).
*
*/
/* ====================================================================
* Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
*
* Portions of the attached software ("Contribution") are developed by
* SUN MICROSYSTEMS, INC., and are contributed to the OpenSSL project.
*
* The Contribution is licensed pursuant to the OpenSSL open source
* license provided above.
*
* ECC cipher suite support in OpenSSL originally written by
* Vipul Gupta and Sumit Gupta of Sun Microsystems Laboratories.
*
*/
/* ====================================================================
* Copyright 2005 Nokia. All rights reserved.
*
* The portions of the attached software ("Contribution") is developed by
* Nokia Corporation and is licensed pursuant to the OpenSSL open source
* license.
*
* The Contribution, originally written by Mika Kousa and Pasi Eronen of
* Nokia Corporation, consists of the "PSK" (Pre-Shared Key) ciphersuites
* support (see RFC 4279) to OpenSSL.
*
* No patent licenses or other rights except those expressly stated in
* the OpenSSL open source license shall be deemed granted or received
* expressly, by implication, estoppel, or otherwise.
*
* No assurances are provided by Nokia that the Contribution does not
* infringe the patent or other intellectual property rights of any third
* party or that the license provides you with all the necessary rights
* to make use of the Contribution.
*
* THE SOFTWARE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. IN
* ADDITION TO THE DISCLAIMERS INCLUDED IN THE LICENSE, NOKIA
* SPECIFICALLY DISCLAIMS ANY LIABILITY FOR CLAIMS BROUGHT BY YOU OR ANY
* OTHER ENTITY BASED ON INFRINGEMENT OF INTELLECTUAL PROPERTY RIGHTS OR
* OTHERWISE. */
#include <openssl/ssl.h>
#include <assert.h>
#include <string.h>
#include <openssl/bn.h>
#include <openssl/buf.h>
#include <openssl/bytestring.h>
#include <openssl/cipher.h>
#include <openssl/ec.h>
#include <openssl/ecdsa.h>
#include <openssl/err.h>
#include <openssl/evp.h>
#include <openssl/hmac.h>
#include <openssl/md5.h>
#include <openssl/mem.h>
#include <openssl/nid.h>
#include <openssl/rand.h>
#include <openssl/x509.h>
#include "internal.h"
#include "../crypto/internal.h"
namespace bssl {
static int ssl3_process_client_hello(SSL_HANDSHAKE *hs);
static int ssl3_select_certificate(SSL_HANDSHAKE *hs);
static int ssl3_select_parameters(SSL_HANDSHAKE *hs);
static int ssl3_send_server_hello(SSL_HANDSHAKE *hs);
static int ssl3_send_server_certificate(SSL_HANDSHAKE *hs);
static int ssl3_send_server_key_exchange(SSL_HANDSHAKE *hs);
static int ssl3_send_server_hello_done(SSL_HANDSHAKE *hs);
static int ssl3_get_client_certificate(SSL_HANDSHAKE *hs);
static int ssl3_get_client_key_exchange(SSL_HANDSHAKE *hs);
static int ssl3_get_cert_verify(SSL_HANDSHAKE *hs);
static int ssl3_get_next_proto(SSL_HANDSHAKE *hs);
static int ssl3_get_channel_id(SSL_HANDSHAKE *hs);
static int ssl3_send_server_finished(SSL_HANDSHAKE *hs);
int ssl3_accept(SSL_HANDSHAKE *hs) {
SSL *const ssl = hs->ssl;
int ret = -1;
assert(ssl->handshake_func == ssl3_accept);
assert(ssl->server);
for (;;) {
int state = hs->state;
switch (hs->state) {
case SSL_ST_INIT:
ssl_do_info_callback(ssl, SSL_CB_HANDSHAKE_START, 1);
hs->state = SSL3_ST_SR_CLNT_HELLO_A;
break;
case SSL3_ST_SR_CLNT_HELLO_A:
ret = ssl->method->ssl_get_message(ssl);
if (ret <= 0) {
goto end;
}
hs->state = SSL3_ST_SR_CLNT_HELLO_B;
break;
case SSL3_ST_SR_CLNT_HELLO_B:
ret = ssl3_process_client_hello(hs);
if (ret <= 0) {
goto end;
}
hs->state = SSL3_ST_SR_CLNT_HELLO_C;
break;
case SSL3_ST_SR_CLNT_HELLO_C:
ret = ssl3_select_certificate(hs);
if (ret <= 0) {
goto end;
}
if (hs->state != SSL_ST_TLS13) {
hs->state = SSL3_ST_SR_CLNT_HELLO_D;
}
break;
case SSL3_ST_SR_CLNT_HELLO_D:
ret = ssl3_select_parameters(hs);
if (ret <= 0) {
goto end;
}
ssl->method->received_flight(ssl);
hs->state = SSL3_ST_SW_SRVR_HELLO_A;
break;
case SSL3_ST_SW_SRVR_HELLO_A:
ret = ssl3_send_server_hello(hs);
if (ret <= 0) {
goto end;
}
if (ssl->session != NULL) {
hs->state = SSL3_ST_SW_FINISHED_A;
} else {
hs->state = SSL3_ST_SW_CERT_A;
}
break;
case SSL3_ST_SW_CERT_A:
ret = ssl3_send_server_certificate(hs);
if (ret <= 0) {
goto end;
}
hs->state = SSL3_ST_SW_KEY_EXCH_A;
break;
case SSL3_ST_SW_KEY_EXCH_A:
if (hs->server_params_len > 0) {
ret = ssl3_send_server_key_exchange(hs);
if (ret <= 0) {
goto end;
}
}
hs->state = SSL3_ST_SW_SRVR_DONE_A;
break;
case SSL3_ST_SW_SRVR_DONE_A:
ret = ssl3_send_server_hello_done(hs);
if (ret <= 0) {
goto end;
}
hs->next_state = SSL3_ST_SR_CERT_A;
hs->state = SSL3_ST_SW_FLUSH;
break;
case SSL3_ST_SR_CERT_A:
if (hs->cert_request) {
ret = ssl3_get_client_certificate(hs);
if (ret <= 0) {
goto end;
}
}
hs->state = SSL3_ST_VERIFY_CLIENT_CERT;
break;
case SSL3_ST_VERIFY_CLIENT_CERT:
if (sk_CRYPTO_BUFFER_num(hs->new_session->certs) > 0) {
switch (ssl_verify_peer_cert(hs)) {
case ssl_verify_ok:
break;
case ssl_verify_invalid:
ret = -1;
goto end;
case ssl_verify_retry:
ssl->rwstate = SSL_CERTIFICATE_VERIFY;
ret = -1;
goto end;
}
}
hs->state = SSL3_ST_SR_KEY_EXCH_A;
break;
case SSL3_ST_SR_KEY_EXCH_A:
case SSL3_ST_SR_KEY_EXCH_B:
ret = ssl3_get_client_key_exchange(hs);
if (ret <= 0) {
goto end;
}
hs->state = SSL3_ST_SR_CERT_VRFY_A;
break;
case SSL3_ST_SR_CERT_VRFY_A:
ret = ssl3_get_cert_verify(hs);
if (ret <= 0) {
goto end;
}
hs->state = SSL3_ST_SR_CHANGE;
break;
case SSL3_ST_SR_CHANGE:
ret = ssl->method->read_change_cipher_spec(ssl);
if (ret <= 0) {
goto end;
}
if (!tls1_change_cipher_state(hs, SSL3_CHANGE_CIPHER_SERVER_READ)) {
ret = -1;
goto end;
}
hs->state = SSL3_ST_SR_NEXT_PROTO_A;
break;
case SSL3_ST_SR_NEXT_PROTO_A:
if (hs->next_proto_neg_seen) {
ret = ssl3_get_next_proto(hs);
if (ret <= 0) {
goto end;
}
}
hs->state = SSL3_ST_SR_CHANNEL_ID_A;
break;
case SSL3_ST_SR_CHANNEL_ID_A:
if (ssl->s3->tlsext_channel_id_valid) {
ret = ssl3_get_channel_id(hs);
if (ret <= 0) {
goto end;
}
}
hs->state = SSL3_ST_SR_FINISHED_A;
break;
case SSL3_ST_SR_FINISHED_A:
ret = ssl3_get_finished(hs);
if (ret <= 0) {
goto end;
}
ssl->method->received_flight(ssl);
if (ssl->session != NULL) {
hs->state = SSL_ST_OK;
} else {
hs->state = SSL3_ST_SW_FINISHED_A;
}
/* If this is a full handshake with ChannelID then record the handshake
* hashes in |hs->new_session| in case we need them to verify a
* ChannelID signature on a resumption of this session in the future. */
if (ssl->session == NULL && ssl->s3->tlsext_channel_id_valid) {
ret = tls1_record_handshake_hashes_for_channel_id(hs);
if (ret <= 0) {
goto end;
}
}
break;
case SSL3_ST_SW_FINISHED_A:
ret = ssl3_send_server_finished(hs);
if (ret <= 0) {
goto end;
}
hs->state = SSL3_ST_SW_FLUSH;
if (ssl->session != NULL) {
hs->next_state = SSL3_ST_SR_CHANGE;
} else {
hs->next_state = SSL_ST_OK;
}
break;
case SSL3_ST_SW_FLUSH:
ret = ssl->method->flush_flight(ssl);
if (ret <= 0) {
goto end;
}
hs->state = hs->next_state;
if (hs->state != SSL_ST_OK) {
ssl->method->expect_flight(ssl);
}
break;
case SSL_ST_TLS13: {
int early_return = 0;
ret = tls13_handshake(hs, &early_return);
if (ret <= 0) {
goto end;
}
if (early_return) {
ret = 1;
goto end;
}
hs->state = SSL_ST_OK;
break;
}
case SSL_ST_OK:
ssl->method->release_current_message(ssl, 1 /* free_buffer */);
/* If we aren't retaining peer certificates then we can discard it
* now. */
if (hs->new_session != NULL &&
ssl->retain_only_sha256_of_client_certs) {
sk_CRYPTO_BUFFER_pop_free(hs->new_session->certs, CRYPTO_BUFFER_free);
hs->new_session->certs = NULL;
ssl->ctx->x509_method->session_clear(hs->new_session.get());
}
SSL_SESSION_free(ssl->s3->established_session);
if (ssl->session != NULL) {
SSL_SESSION_up_ref(ssl->session);
ssl->s3->established_session = ssl->session;
} else {
ssl->s3->established_session = hs->new_session.release();
ssl->s3->established_session->not_resumable = 0;
}
ssl->s3->initial_handshake_complete = 1;
ssl_update_cache(hs, SSL_SESS_CACHE_SERVER);
ssl_do_info_callback(ssl, SSL_CB_HANDSHAKE_DONE, 1);
ret = 1;
goto end;
default:
OPENSSL_PUT_ERROR(SSL, SSL_R_UNKNOWN_STATE);
ret = -1;
goto end;
}
if (hs->state != state) {
ssl_do_info_callback(ssl, SSL_CB_ACCEPT_LOOP, 1);
}
}
end:
ssl_do_info_callback(ssl, SSL_CB_ACCEPT_EXIT, ret);
return ret;
}
int ssl_client_cipher_list_contains_cipher(const SSL_CLIENT_HELLO *client_hello,
uint16_t id) {
CBS cipher_suites;
CBS_init(&cipher_suites, client_hello->cipher_suites,
client_hello->cipher_suites_len);
while (CBS_len(&cipher_suites) > 0) {
uint16_t got_id;
if (!CBS_get_u16(&cipher_suites, &got_id)) {
return 0;
}
if (got_id == id) {
return 1;
}
}
return 0;
}
static int negotiate_version(SSL_HANDSHAKE *hs, uint8_t *out_alert,
const SSL_CLIENT_HELLO *client_hello) {
SSL *const ssl = hs->ssl;
assert(!ssl->s3->have_version);
CBS supported_versions, versions;
if (ssl_client_hello_get_extension(client_hello, &supported_versions,
TLSEXT_TYPE_supported_versions)) {
if (!CBS_get_u8_length_prefixed(&supported_versions, &versions) ||
CBS_len(&supported_versions) != 0 ||
CBS_len(&versions) == 0) {
OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
*out_alert = SSL_AD_DECODE_ERROR;
return 0;
}
} else {
/* Convert the ClientHello version to an equivalent supported_versions
* extension. */
static const uint8_t kTLSVersions[] = {
0x03, 0x03, /* TLS 1.2 */
0x03, 0x02, /* TLS 1.1 */
0x03, 0x01, /* TLS 1 */
0x03, 0x00, /* SSL 3 */
};
static const uint8_t kDTLSVersions[] = {
0xfe, 0xfd, /* DTLS 1.2 */
0xfe, 0xff, /* DTLS 1.0 */
};
size_t versions_len = 0;
if (SSL_is_dtls(ssl)) {
if (client_hello->version <= DTLS1_2_VERSION) {
versions_len = 4;
} else if (client_hello->version <= DTLS1_VERSION) {
versions_len = 2;
}
CBS_init(&versions, kDTLSVersions + sizeof(kDTLSVersions) - versions_len,
versions_len);
} else {
if (client_hello->version >= TLS1_2_VERSION) {
versions_len = 8;
} else if (client_hello->version >= TLS1_1_VERSION) {
versions_len = 6;
} else if (client_hello->version >= TLS1_VERSION) {
versions_len = 4;
} else if (client_hello->version >= SSL3_VERSION) {
versions_len = 2;
}
CBS_init(&versions, kTLSVersions + sizeof(kTLSVersions) - versions_len,
versions_len);
}
}
if (!ssl_negotiate_version(hs, out_alert, &ssl->version, &versions)) {
return 0;
}
/* At this point, the connection's version is known and |ssl->version| is
* fixed. Begin enforcing the record-layer version. */
ssl->s3->have_version = 1;
/* Handle FALLBACK_SCSV. */
if (ssl_client_cipher_list_contains_cipher(client_hello,
SSL3_CK_FALLBACK_SCSV & 0xffff) &&
ssl3_protocol_version(ssl) < hs->max_version) {
OPENSSL_PUT_ERROR(SSL, SSL_R_INAPPROPRIATE_FALLBACK);
*out_alert = SSL3_AD_INAPPROPRIATE_FALLBACK;
return 0;
}
return 1;
}
static STACK_OF(SSL_CIPHER) *
ssl_parse_client_cipher_list(const SSL_CLIENT_HELLO *client_hello) {
CBS cipher_suites;
CBS_init(&cipher_suites, client_hello->cipher_suites,
client_hello->cipher_suites_len);
STACK_OF(SSL_CIPHER) *sk = sk_SSL_CIPHER_new_null();
if (sk == NULL) {
OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
goto err;
}
while (CBS_len(&cipher_suites) > 0) {
uint16_t cipher_suite;
if (!CBS_get_u16(&cipher_suites, &cipher_suite)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_ERROR_IN_RECEIVED_CIPHER_LIST);
goto err;
}
const SSL_CIPHER *c = SSL_get_cipher_by_value(cipher_suite);
if (c != NULL && !sk_SSL_CIPHER_push(sk, c)) {
OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
goto err;
}
}
return sk;
err:
sk_SSL_CIPHER_free(sk);
return NULL;
}
/* ssl_get_compatible_server_ciphers determines the key exchange and
* authentication cipher suite masks compatible with the server configuration
* and current ClientHello parameters of |hs|. It sets |*out_mask_k| to the key
* exchange mask and |*out_mask_a| to the authentication mask. */
static void ssl_get_compatible_server_ciphers(SSL_HANDSHAKE *hs,
uint32_t *out_mask_k,
uint32_t *out_mask_a) {
SSL *const ssl = hs->ssl;
uint32_t mask_k = 0;
uint32_t mask_a = 0;
if (ssl_has_certificate(ssl)) {
mask_a |= ssl_cipher_auth_mask_for_key(hs->local_pubkey.get());
if (EVP_PKEY_id(hs->local_pubkey.get()) == EVP_PKEY_RSA) {
mask_k |= SSL_kRSA;
}
}
/* Check for a shared group to consider ECDHE ciphers. */
uint16_t unused;
if (tls1_get_shared_group(hs, &unused)) {
mask_k |= SSL_kECDHE;
}
/* PSK requires a server callback. */
if (ssl->psk_server_callback != NULL) {
mask_k |= SSL_kPSK;
mask_a |= SSL_aPSK;
}
*out_mask_k = mask_k;
*out_mask_a = mask_a;
}
static const SSL_CIPHER *ssl3_choose_cipher(
SSL_HANDSHAKE *hs, const SSL_CLIENT_HELLO *client_hello,
const struct ssl_cipher_preference_list_st *server_pref) {
SSL *const ssl = hs->ssl;
STACK_OF(SSL_CIPHER) *prio, *allow;
/* in_group_flags will either be NULL, or will point to an array of bytes
* which indicate equal-preference groups in the |prio| stack. See the
* comment about |in_group_flags| in the |ssl_cipher_preference_list_st|
* struct. */
const uint8_t *in_group_flags;
/* group_min contains the minimal index so far found in a group, or -1 if no
* such value exists yet. */
int group_min = -1;
STACK_OF(SSL_CIPHER) *client_pref =
ssl_parse_client_cipher_list(client_hello);
if (client_pref == NULL) {
return NULL;
}
if (ssl->options & SSL_OP_CIPHER_SERVER_PREFERENCE) {
prio = server_pref->ciphers;
in_group_flags = server_pref->in_group_flags;
allow = client_pref;
} else {
prio = client_pref;
in_group_flags = NULL;
allow = server_pref->ciphers;
}
uint32_t mask_k, mask_a;
ssl_get_compatible_server_ciphers(hs, &mask_k, &mask_a);
const SSL_CIPHER *ret = NULL;
for (size_t i = 0; i < sk_SSL_CIPHER_num(prio); i++) {
const SSL_CIPHER *c = sk_SSL_CIPHER_value(prio, i);
size_t cipher_index;
if (/* Check if the cipher is supported for the current version. */
SSL_CIPHER_get_min_version(c) <= ssl3_protocol_version(ssl) &&
ssl3_protocol_version(ssl) <= SSL_CIPHER_get_max_version(c) &&
/* Check the cipher is supported for the server configuration. */
(c->algorithm_mkey & mask_k) &&
(c->algorithm_auth & mask_a) &&
/* Check the cipher is in the |allow| list. */
sk_SSL_CIPHER_find(allow, &cipher_index, c)) {
if (in_group_flags != NULL && in_group_flags[i] == 1) {
/* This element of |prio| is in a group. Update the minimum index found
* so far and continue looking. */
if (group_min == -1 || (size_t)group_min > cipher_index) {
group_min = cipher_index;
}
} else {
if (group_min != -1 && (size_t)group_min < cipher_index) {
cipher_index = group_min;
}
ret = sk_SSL_CIPHER_value(allow, cipher_index);
break;
}
}
if (in_group_flags != NULL && in_group_flags[i] == 0 && group_min != -1) {
/* We are about to leave a group, but we found a match in it, so that's
* our answer. */
ret = sk_SSL_CIPHER_value(allow, group_min);
break;
}
}
sk_SSL_CIPHER_free(client_pref);
return ret;
}
static int ssl3_process_client_hello(SSL_HANDSHAKE *hs) {
SSL *const ssl = hs->ssl;
if (!ssl_check_message_type(ssl, SSL3_MT_CLIENT_HELLO)) {
return -1;
}
SSL_CLIENT_HELLO client_hello;
if (!ssl_client_hello_init(ssl, &client_hello, ssl->init_msg,
ssl->init_num)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
return -1;
}
/* Run the early callback. */
if (ssl->ctx->select_certificate_cb != NULL) {
switch (ssl->ctx->select_certificate_cb(&client_hello)) {
case ssl_select_cert_retry:
ssl->rwstate = SSL_CERTIFICATE_SELECTION_PENDING;
return -1;
case ssl_select_cert_error:
/* Connection rejected. */
OPENSSL_PUT_ERROR(SSL, SSL_R_CONNECTION_REJECTED);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
return -1;
default:
/* fallthrough */;
}
}
/* Freeze the version range after the early callback. */
if (!ssl_get_version_range(ssl, &hs->min_version, &hs->max_version)) {
return -1;
}
uint8_t alert = SSL_AD_DECODE_ERROR;
if (!negotiate_version(hs, &alert, &client_hello)) {
ssl3_send_alert(ssl, SSL3_AL_FATAL, alert);
return -1;
}
hs->client_version = client_hello.version;
if (client_hello.random_len != SSL3_RANDOM_SIZE) {
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
return -1;
}
OPENSSL_memcpy(ssl->s3->client_random, client_hello.random,
client_hello.random_len);
/* Only null compression is supported. TLS 1.3 further requires the peer
* advertise no other compression. */
if (OPENSSL_memchr(client_hello.compression_methods, 0,
client_hello.compression_methods_len) == NULL ||
(ssl3_protocol_version(ssl) >= TLS1_3_VERSION &&
client_hello.compression_methods_len != 1)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_COMPRESSION_LIST);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
return -1;
}
/* TLS extensions. */
if (!ssl_parse_clienthello_tlsext(hs, &client_hello)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_PARSE_TLSEXT);
return -1;
}
return 1;
}
static int ssl3_select_certificate(SSL_HANDSHAKE *hs) {
SSL *const ssl = hs->ssl;
/* Call |cert_cb| to update server certificates if required. */
if (ssl->cert->cert_cb != NULL) {
int rv = ssl->cert->cert_cb(ssl, ssl->cert->cert_cb_arg);
if (rv == 0) {
OPENSSL_PUT_ERROR(SSL, SSL_R_CERT_CB_ERROR);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
return -1;
}
if (rv < 0) {
ssl->rwstate = SSL_X509_LOOKUP;
return -1;
}
}
if (!ssl_on_certificate_selected(hs)) {
return -1;
}
if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION) {
/* Jump to the TLS 1.3 state machine. */
hs->state = SSL_ST_TLS13;
hs->do_tls13_handshake = tls13_server_handshake;
return 1;
}
SSL_CLIENT_HELLO client_hello;
if (!ssl_client_hello_init(ssl, &client_hello, ssl->init_msg,
ssl->init_num)) {
return -1;
}
/* Negotiate the cipher suite. This must be done after |cert_cb| so the
* certificate is finalized. */
hs->new_cipher =
ssl3_choose_cipher(hs, &client_hello, ssl_get_cipher_preferences(ssl));
if (hs->new_cipher == NULL) {
OPENSSL_PUT_ERROR(SSL, SSL_R_NO_SHARED_CIPHER);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
return -1;
}
return 1;
}
static int ssl3_select_parameters(SSL_HANDSHAKE *hs) {
SSL *const ssl = hs->ssl;
SSL_CLIENT_HELLO client_hello;
if (!ssl_client_hello_init(ssl, &client_hello, ssl->init_msg,
ssl->init_num)) {
return -1;
}
/* Determine whether we are doing session resumption. */
int tickets_supported = 0, renew_ticket = 0;
/* TODO(davidben): Switch |ssl_get_prev_session| to take a |UniquePtr|
* output and simplify this. */
SSL_SESSION *session_raw = nullptr;
auto session_ret = ssl_get_prev_session(ssl, &session_raw, &tickets_supported,
&renew_ticket, &client_hello);
UniquePtr<SSL_SESSION> session(session_raw);
switch (session_ret) {
case ssl_session_success:
break;
case ssl_session_error:
return -1;
case ssl_session_retry:
ssl->rwstate = SSL_PENDING_SESSION;
return -1;
case ssl_session_ticket_retry:
ssl->rwstate = SSL_PENDING_TICKET;
return -1;
}
if (session) {
if (session->extended_master_secret && !hs->extended_master_secret) {
/* A ClientHello without EMS that attempts to resume a session with EMS
* is fatal to the connection. */
OPENSSL_PUT_ERROR(SSL, SSL_R_RESUMED_EMS_SESSION_WITHOUT_EMS_EXTENSION);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
return -1;
}
if (!ssl_session_is_resumable(hs, session.get()) ||
/* If the client offers the EMS extension, but the previous session
* didn't use it, then negotiate a new session. */
hs->extended_master_secret != session->extended_master_secret) {
session.reset();
}
}
if (session) {
/* Use the old session. */
hs->ticket_expected = renew_ticket;
ssl->session = session.release();
ssl->s3->session_reused = 1;
} else {
hs->ticket_expected = tickets_supported;
ssl_set_session(ssl, NULL);
if (!ssl_get_new_session(hs, 1 /* server */)) {
return -1;
}
/* Clear the session ID if we want the session to be single-use. */
if (!(ssl->ctx->session_cache_mode & SSL_SESS_CACHE_SERVER)) {
hs->new_session->session_id_length = 0;
}
}
if (ssl->ctx->dos_protection_cb != NULL &&
ssl->ctx->dos_protection_cb(&client_hello) == 0) {
/* Connection rejected for DOS reasons. */
OPENSSL_PUT_ERROR(SSL, SSL_R_CONNECTION_REJECTED);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
return -1;
}
if (ssl->session == NULL) {
hs->new_session->cipher = hs->new_cipher;
/* On new sessions, stash the SNI value in the session. */
if (hs->hostname != NULL) {
OPENSSL_free(hs->new_session->tlsext_hostname);
hs->new_session->tlsext_hostname = BUF_strdup(hs->hostname.get());
if (hs->new_session->tlsext_hostname == NULL) {
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
return -1;
}
}
/* Determine whether to request a client certificate. */
hs->cert_request = !!(ssl->verify_mode & SSL_VERIFY_PEER);
/* Only request a certificate if Channel ID isn't negotiated. */
if ((ssl->verify_mode & SSL_VERIFY_PEER_IF_NO_OBC) &&
ssl->s3->tlsext_channel_id_valid) {
hs->cert_request = 0;
}
/* CertificateRequest may only be sent in certificate-based ciphers. */
if (!ssl_cipher_uses_certificate_auth(hs->new_cipher)) {
hs->cert_request = 0;
}
if (!hs->cert_request) {
/* OpenSSL returns X509_V_OK when no certificates are requested. This is
* classed by them as a bug, but it's assumed by at least NGINX. */
hs->new_session->verify_result = X509_V_OK;
}
}
/* HTTP/2 negotiation depends on the cipher suite, so ALPN negotiation was
* deferred. Complete it now. */
uint8_t alert = SSL_AD_DECODE_ERROR;
if (!ssl_negotiate_alpn(hs, &alert, &client_hello)) {
ssl3_send_alert(ssl, SSL3_AL_FATAL, alert);
return -1;
}
/* Now that all parameters are known, initialize the handshake hash and hash
* the ClientHello. */
if (!hs->transcript.InitHash(ssl3_protocol_version(ssl),
hs->new_cipher->algorithm_prf) ||
!ssl_hash_current_message(hs)) {
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
return -1;
}
/* Release the handshake buffer if client authentication isn't required. */
if (!hs->cert_request) {
hs->transcript.FreeBuffer();
}
return 1;
}
static int ssl3_send_server_hello(SSL_HANDSHAKE *hs) {
SSL *const ssl = hs->ssl;
/* We only accept ChannelIDs on connections with ECDHE in order to avoid a
* known attack while we fix ChannelID itself. */
if (ssl->s3->tlsext_channel_id_valid &&
(hs->new_cipher->algorithm_mkey & SSL_kECDHE) == 0) {
ssl->s3->tlsext_channel_id_valid = 0;
}
/* If this is a resumption and the original handshake didn't support
* ChannelID then we didn't record the original handshake hashes in the
* session and so cannot resume with ChannelIDs. */
if (ssl->session != NULL &&
ssl->session->original_handshake_hash_len == 0) {
ssl->s3->tlsext_channel_id_valid = 0;
}
struct OPENSSL_timeval now;
ssl_get_current_time(ssl, &now);
ssl->s3->server_random[0] = now.tv_sec >> 24;
ssl->s3->server_random[1] = now.tv_sec >> 16;
ssl->s3->server_random[2] = now.tv_sec >> 8;
ssl->s3->server_random[3] = now.tv_sec;
if (!RAND_bytes(ssl->s3->server_random + 4, SSL3_RANDOM_SIZE - 4)) {
return -1;
}
/* TODO(davidben): Implement the TLS 1.1 and 1.2 downgrade sentinels once TLS
* 1.3 is finalized and we are not implementing a draft version. */
const SSL_SESSION *session = hs->new_session.get();
if (ssl->session != NULL) {
session = ssl->session;
}
ScopedCBB cbb;
CBB body, session_id;
if (!ssl->method->init_message(ssl, cbb.get(), &body, SSL3_MT_SERVER_HELLO) ||
!CBB_add_u16(&body, ssl->version) ||
!CBB_add_bytes(&body, ssl->s3->server_random, SSL3_RANDOM_SIZE) ||
!CBB_add_u8_length_prefixed(&body, &session_id) ||
!CBB_add_bytes(&session_id, session->session_id,
session->session_id_length) ||
!CBB_add_u16(&body, ssl_cipher_get_value(hs->new_cipher)) ||
!CBB_add_u8(&body, 0 /* no compression */) ||
!ssl_add_serverhello_tlsext(hs, &body) ||
!ssl_add_message_cbb(ssl, cbb.get())) {
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
return -1;
}
return 1;
}
static int ssl3_send_server_certificate(SSL_HANDSHAKE *hs) {
SSL *const ssl = hs->ssl;
ScopedCBB cbb;
if (ssl_cipher_uses_certificate_auth(hs->new_cipher)) {
if (!ssl_has_certificate(ssl)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_NO_CERTIFICATE_SET);
return -1;
}
if (!ssl3_output_cert_chain(ssl)) {
return -1;
}
if (hs->certificate_status_expected) {
CBB body, ocsp_response;
if (!ssl->method->init_message(ssl, cbb.get(), &body,
SSL3_MT_CERTIFICATE_STATUS) ||
!CBB_add_u8(&body, TLSEXT_STATUSTYPE_ocsp) ||
!CBB_add_u24_length_prefixed(&body, &ocsp_response) ||
!CBB_add_bytes(&ocsp_response,
CRYPTO_BUFFER_data(ssl->cert->ocsp_response),
CRYPTO_BUFFER_len(ssl->cert->ocsp_response)) ||
!ssl_add_message_cbb(ssl, cbb.get())) {
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
return -1;
}
}
}
/* Assemble ServerKeyExchange parameters if needed. */
uint32_t alg_k = hs->new_cipher->algorithm_mkey;
uint32_t alg_a = hs->new_cipher->algorithm_auth;
if (ssl_cipher_requires_server_key_exchange(hs->new_cipher) ||
((alg_a & SSL_aPSK) && ssl->psk_identity_hint)) {
/* Pre-allocate enough room to comfortably fit an ECDHE public key. Prepend
* the client and server randoms for the signing transcript. */
CBB child;
if (!CBB_init(cbb.get(), SSL3_RANDOM_SIZE * 2 + 128) ||
!CBB_add_bytes(cbb.get(), ssl->s3->client_random, SSL3_RANDOM_SIZE) ||
!CBB_add_bytes(cbb.get(), ssl->s3->server_random, SSL3_RANDOM_SIZE)) {
return -1;
}
/* PSK ciphers begin with an identity hint. */
if (alg_a & SSL_aPSK) {
size_t len =
(ssl->psk_identity_hint == NULL) ? 0 : strlen(ssl->psk_identity_hint);
if (!CBB_add_u16_length_prefixed(cbb.get(), &child) ||
!CBB_add_bytes(&child, (const uint8_t *)ssl->psk_identity_hint,
len)) {
return -1;
}
}
if (alg_k & SSL_kECDHE) {
/* Determine the group to use. */
uint16_t group_id;
if (!tls1_get_shared_group(hs, &group_id)) {
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
return -1;
}
hs->new_session->group_id = group_id;
/* Set up ECDH, generate a key, and emit the public half. */
hs->key_share = SSLKeyShare::Create(group_id);
if (!hs->key_share ||
!CBB_add_u8(cbb.get(), NAMED_CURVE_TYPE) ||
!CBB_add_u16(cbb.get(), group_id) ||
!CBB_add_u8_length_prefixed(cbb.get(), &child) ||
!hs->key_share->Offer(&child)) {
return -1;
}
} else {
assert(alg_k & SSL_kPSK);
}
if (!CBB_finish(cbb.get(), &hs->server_params, &hs->server_params_len)) {
return -1;
}
}
return 1;
}
static int ssl3_send_server_key_exchange(SSL_HANDSHAKE *hs) {
SSL *const ssl = hs->ssl;
ScopedCBB cbb;
CBB body, child;
if (!ssl->method->init_message(ssl, cbb.get(), &body,
SSL3_MT_SERVER_KEY_EXCHANGE) ||
/* |hs->server_params| contains a prefix for signing. */
hs->server_params_len < 2 * SSL3_RANDOM_SIZE ||
!CBB_add_bytes(&body, hs->server_params + 2 * SSL3_RANDOM_SIZE,
hs->server_params_len - 2 * SSL3_RANDOM_SIZE)) {
return -1;
}
/* Add a signature. */
if (ssl_cipher_uses_certificate_auth(hs->new_cipher)) {
if (!ssl_has_private_key(ssl)) {
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
return -1;
}
/* Determine the signature algorithm. */
uint16_t signature_algorithm;
if (!tls1_choose_signature_algorithm(hs, &signature_algorithm)) {
return -1;
}
if (ssl3_protocol_version(ssl) >= TLS1_2_VERSION) {
if (!CBB_add_u16(&body, signature_algorithm)) {
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
return -1;
}
}
/* Add space for the signature. */
const size_t max_sig_len = EVP_PKEY_size(hs->local_pubkey.get());
uint8_t *ptr;
if (!CBB_add_u16_length_prefixed(&body, &child) ||
!CBB_reserve(&child, &ptr, max_sig_len)) {
return -1;
}
size_t sig_len;
switch (ssl_private_key_sign(hs, ptr, &sig_len, max_sig_len,
signature_algorithm, hs->server_params,
hs->server_params_len)) {
case ssl_private_key_success:
if (!CBB_did_write(&child, sig_len)) {
return -1;
}
break;
case ssl_private_key_failure:
return -1;
case ssl_private_key_retry:
ssl->rwstate = SSL_PRIVATE_KEY_OPERATION;
return -1;
}
}
if (!ssl_add_message_cbb(ssl, cbb.get())) {
return -1;
}
OPENSSL_free(hs->server_params);
hs->server_params = NULL;
hs->server_params_len = 0;
return 1;
}
static int ssl3_send_server_hello_done(SSL_HANDSHAKE *hs) {
SSL *const ssl = hs->ssl;
ScopedCBB cbb;
CBB body;
if (hs->cert_request) {
CBB cert_types, sigalgs_cbb;
if (!ssl->method->init_message(ssl, cbb.get(), &body,
SSL3_MT_CERTIFICATE_REQUEST) ||
!CBB_add_u8_length_prefixed(&body, &cert_types) ||
!CBB_add_u8(&cert_types, SSL3_CT_RSA_SIGN) ||
(ssl3_protocol_version(ssl) >= TLS1_VERSION &&
!CBB_add_u8(&cert_types, TLS_CT_ECDSA_SIGN)) ||
(ssl3_protocol_version(ssl) >= TLS1_2_VERSION &&
(!CBB_add_u16_length_prefixed(&body, &sigalgs_cbb) ||
!tls12_add_verify_sigalgs(ssl, &sigalgs_cbb))) ||
!ssl_add_client_CA_list(ssl, &body) ||
!ssl_add_message_cbb(ssl, cbb.get())) {
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
return -1;
}
}
if (!ssl->method->init_message(ssl, cbb.get(), &body,
SSL3_MT_SERVER_HELLO_DONE) ||
!ssl_add_message_cbb(ssl, cbb.get())) {
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
return -1;
}
return 1;
}
static int ssl3_get_client_certificate(SSL_HANDSHAKE *hs) {
SSL *const ssl = hs->ssl;
assert(hs->cert_request);
int msg_ret = ssl->method->ssl_get_message(ssl);
if (msg_ret <= 0) {
return msg_ret;
}
if (ssl->s3->tmp.message_type != SSL3_MT_CERTIFICATE) {
if (ssl->version == SSL3_VERSION &&
ssl->s3->tmp.message_type == SSL3_MT_CLIENT_KEY_EXCHANGE) {
/* In SSL 3.0, the Certificate message is omitted to signal no
* certificate. */
if (ssl->verify_mode & SSL_VERIFY_FAIL_IF_NO_PEER_CERT) {
OPENSSL_PUT_ERROR(SSL, SSL_R_PEER_DID_NOT_RETURN_A_CERTIFICATE);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
return -1;
}
/* OpenSSL returns X509_V_OK when no certificates are received. This is
* classed by them as a bug, but it's assumed by at least NGINX. */
hs->new_session->verify_result = X509_V_OK;
ssl->s3->tmp.reuse_message = 1;
return 1;
}
OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_MESSAGE);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE);
return -1;
}
if (!ssl_hash_current_message(hs)) {
return -1;
}
CBS certificate_msg;
CBS_init(&certificate_msg, ssl->init_msg, ssl->init_num);
sk_CRYPTO_BUFFER_pop_free(hs->new_session->certs, CRYPTO_BUFFER_free);
hs->peer_pubkey.reset();
uint8_t alert = SSL_AD_DECODE_ERROR;
hs->new_session->certs =
ssl_parse_cert_chain(&alert, &hs->peer_pubkey,
ssl->retain_only_sha256_of_client_certs
? hs->new_session->peer_sha256
: NULL,
&certificate_msg, ssl->ctx->pool)
.release();
if (hs->new_session->certs == NULL) {
ssl3_send_alert(ssl, SSL3_AL_FATAL, alert);
return -1;
}
if (CBS_len(&certificate_msg) != 0 ||
!ssl->ctx->x509_method->session_cache_objects(hs->new_session.get())) {
OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
return -1;
}
if (sk_CRYPTO_BUFFER_num(hs->new_session->certs) == 0) {
/* No client certificate so the handshake buffer may be discarded. */
hs->transcript.FreeBuffer();
/* In SSL 3.0, sending no certificate is signaled by omitting the
* Certificate message. */
if (ssl->version == SSL3_VERSION) {
OPENSSL_PUT_ERROR(SSL, SSL_R_NO_CERTIFICATES_RETURNED);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
return -1;
}
if (ssl->verify_mode & SSL_VERIFY_FAIL_IF_NO_PEER_CERT) {
/* Fail for TLS only if we required a certificate */
OPENSSL_PUT_ERROR(SSL, SSL_R_PEER_DID_NOT_RETURN_A_CERTIFICATE);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
return -1;
}
/* OpenSSL returns X509_V_OK when no certificates are received. This is
* classed by them as a bug, but it's assumed by at least NGINX. */
hs->new_session->verify_result = X509_V_OK;
return 1;
}
/* The hash will have been filled in. */
if (ssl->retain_only_sha256_of_client_certs) {
hs->new_session->peer_sha256_valid = 1;
}
return 1;
}
static int ssl3_get_client_key_exchange(SSL_HANDSHAKE *hs) {
SSL *const ssl = hs->ssl;
CBS client_key_exchange;
uint8_t *premaster_secret = NULL;
size_t premaster_secret_len = 0;
uint8_t *decrypt_buf = NULL;
if (hs->state == SSL3_ST_SR_KEY_EXCH_A) {
int ret = ssl->method->ssl_get_message(ssl);
if (ret <= 0) {
return ret;
}
}
if (!ssl_check_message_type(ssl, SSL3_MT_CLIENT_KEY_EXCHANGE)) {
return -1;
}
CBS_init(&client_key_exchange, ssl->init_msg, ssl->init_num);
uint32_t alg_k = hs->new_cipher->algorithm_mkey;
uint32_t alg_a = hs->new_cipher->algorithm_auth;
/* If using a PSK key exchange, parse the PSK identity. */
if (alg_a & SSL_aPSK) {
CBS psk_identity;
/* If using PSK, the ClientKeyExchange contains a psk_identity. If PSK,
* then this is the only field in the message. */
if (!CBS_get_u16_length_prefixed(&client_key_exchange, &psk_identity) ||
((alg_k & SSL_kPSK) && CBS_len(&client_key_exchange) != 0)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
goto err;
}
if (CBS_len(&psk_identity) > PSK_MAX_IDENTITY_LEN ||
CBS_contains_zero_byte(&psk_identity)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_DATA_LENGTH_TOO_LONG);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
goto err;
}
if (!CBS_strdup(&psk_identity, &hs->new_session->psk_identity)) {
OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
goto err;
}
}
/* Depending on the key exchange method, compute |premaster_secret| and
* |premaster_secret_len|. */
if (alg_k & SSL_kRSA) {
CBS encrypted_premaster_secret;
if (ssl->version > SSL3_VERSION) {
if (!CBS_get_u16_length_prefixed(&client_key_exchange,
&encrypted_premaster_secret) ||
CBS_len(&client_key_exchange) != 0) {
OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
goto err;
}
} else {
encrypted_premaster_secret = client_key_exchange;
}
/* Allocate a buffer large enough for an RSA decryption. */
const size_t rsa_size = EVP_PKEY_size(hs->local_pubkey.get());
decrypt_buf = (uint8_t *)OPENSSL_malloc(rsa_size);
if (decrypt_buf == NULL) {
OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
goto err;
}
/* Decrypt with no padding. PKCS#1 padding will be removed as part of the
* timing-sensitive code below. */
size_t decrypt_len;
switch (ssl_private_key_decrypt(hs, decrypt_buf, &decrypt_len, rsa_size,
CBS_data(&encrypted_premaster_secret),
CBS_len(&encrypted_premaster_secret))) {
case ssl_private_key_success:
break;
case ssl_private_key_failure:
goto err;
case ssl_private_key_retry:
ssl->rwstate = SSL_PRIVATE_KEY_OPERATION;
hs->state = SSL3_ST_SR_KEY_EXCH_B;
goto err;
}
if (decrypt_len != rsa_size) {
OPENSSL_PUT_ERROR(SSL, SSL_R_DECRYPTION_FAILED);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECRYPT_ERROR);
goto err;
}
/* Prepare a random premaster, to be used on invalid padding. See RFC 5246,
* section 7.4.7.1. */
premaster_secret_len = SSL_MAX_MASTER_KEY_LENGTH;
premaster_secret = (uint8_t *)OPENSSL_malloc(premaster_secret_len);
if (premaster_secret == NULL) {
OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
goto err;
}
if (!RAND_bytes(premaster_secret, premaster_secret_len)) {
goto err;
}
/* The smallest padded premaster is 11 bytes of overhead. Small keys are
* publicly invalid. */
if (decrypt_len < 11 + premaster_secret_len) {
OPENSSL_PUT_ERROR(SSL, SSL_R_DECRYPTION_FAILED);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECRYPT_ERROR);
goto err;
}
/* Check the padding. See RFC 3447, section 7.2.2. */
size_t padding_len = decrypt_len - premaster_secret_len;
uint8_t good = constant_time_eq_int_8(decrypt_buf[0], 0) &
constant_time_eq_int_8(decrypt_buf[1], 2);
for (size_t i = 2; i < padding_len - 1; i++) {
good &= ~constant_time_is_zero_8(decrypt_buf[i]);
}
good &= constant_time_is_zero_8(decrypt_buf[padding_len - 1]);
/* The premaster secret must begin with |client_version|. This too must be
* checked in constant time (http://eprint.iacr.org/2003/052/). */
good &= constant_time_eq_8(decrypt_buf[padding_len],
(unsigned)(hs->client_version >> 8));
good &= constant_time_eq_8(decrypt_buf[padding_len + 1],
(unsigned)(hs->client_version & 0xff));
/* Select, in constant time, either the decrypted premaster or the random
* premaster based on |good|. */
for (size_t i = 0; i < premaster_secret_len; i++) {
premaster_secret[i] = constant_time_select_8(
good, decrypt_buf[padding_len + i], premaster_secret[i]);
}
OPENSSL_free(decrypt_buf);
decrypt_buf = NULL;
} else if (alg_k & SSL_kECDHE) {
/* Parse the ClientKeyExchange. */
CBS peer_key;
if (!CBS_get_u8_length_prefixed(&client_key_exchange, &peer_key) ||
CBS_len(&client_key_exchange) != 0) {
OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
goto err;
}
/* Compute the premaster. */
uint8_t alert = SSL_AD_DECODE_ERROR;
if (!hs->key_share->Finish(&premaster_secret, &premaster_secret_len, &alert,
CBS_data(&peer_key), CBS_len(&peer_key))) {
ssl3_send_alert(ssl, SSL3_AL_FATAL, alert);
goto err;
}
/* The key exchange state may now be discarded. */
hs->key_share.reset();
} else if (!(alg_k & SSL_kPSK)) {
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
goto err;
}
/* For a PSK cipher suite, the actual pre-master secret is combined with the
* pre-shared key. */
if (alg_a & SSL_aPSK) {
if (ssl->psk_server_callback == NULL) {
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
goto err;
}
/* Look up the key for the identity. */
uint8_t psk[PSK_MAX_PSK_LEN];
unsigned psk_len = ssl->psk_server_callback(
ssl, hs->new_session->psk_identity, psk, sizeof(psk));
if (psk_len > PSK_MAX_PSK_LEN) {
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
goto err;
} else if (psk_len == 0) {
/* PSK related to the given identity not found */
OPENSSL_PUT_ERROR(SSL, SSL_R_PSK_IDENTITY_NOT_FOUND);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNKNOWN_PSK_IDENTITY);
goto err;
}
if (alg_k & SSL_kPSK) {
/* In plain PSK, other_secret is a block of 0s with the same length as the
* pre-shared key. */
premaster_secret_len = psk_len;
premaster_secret = (uint8_t *)OPENSSL_malloc(premaster_secret_len);
if (premaster_secret == NULL) {
OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
goto err;
}
OPENSSL_memset(premaster_secret, 0, premaster_secret_len);
}
ScopedCBB new_premaster;
CBB child;
uint8_t *new_data;
size_t new_len;
if (!CBB_init(new_premaster.get(),
2 + psk_len + 2 + premaster_secret_len) ||
!CBB_add_u16_length_prefixed(new_premaster.get(), &child) ||
!CBB_add_bytes(&child, premaster_secret, premaster_secret_len) ||
!CBB_add_u16_length_prefixed(new_premaster.get(), &child) ||
!CBB_add_bytes(&child, psk, psk_len) ||
!CBB_finish(new_premaster.get(), &new_data, &new_len)) {
OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
goto err;
}
OPENSSL_cleanse(premaster_secret, premaster_secret_len);
OPENSSL_free(premaster_secret);
premaster_secret = new_data;
premaster_secret_len = new_len;
}
if (!ssl_hash_current_message(hs)) {
goto err;
}
/* Compute the master secret */
hs->new_session->master_key_length = tls1_generate_master_secret(
hs, hs->new_session->master_key, premaster_secret, premaster_secret_len);
if (hs->new_session->master_key_length == 0) {
goto err;
}
hs->new_session->extended_master_secret = hs->extended_master_secret;
OPENSSL_cleanse(premaster_secret, premaster_secret_len);
OPENSSL_free(premaster_secret);
return 1;
err:
if (premaster_secret != NULL) {
OPENSSL_cleanse(premaster_secret, premaster_secret_len);
OPENSSL_free(premaster_secret);
}
OPENSSL_free(decrypt_buf);
return -1;
}
static int ssl3_get_cert_verify(SSL_HANDSHAKE *hs) {
SSL *const ssl = hs->ssl;
CBS certificate_verify, signature;
/* Only RSA and ECDSA client certificates are supported, so a
* CertificateVerify is required if and only if there's a client certificate.
* */
if (!hs->peer_pubkey) {
hs->transcript.FreeBuffer();
return 1;
}
int msg_ret = ssl->method->ssl_get_message(ssl);
if (msg_ret <= 0) {
return msg_ret;
}
if (!ssl_check_message_type(ssl, SSL3_MT_CERTIFICATE_VERIFY)) {
return -1;
}
CBS_init(&certificate_verify, ssl->init_msg, ssl->init_num);
/* Determine the digest type if needbe. */
uint16_t signature_algorithm = 0;
if (ssl3_protocol_version(ssl) >= TLS1_2_VERSION) {
if (!CBS_get_u16(&certificate_verify, &signature_algorithm)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
return -1;
}
uint8_t alert = SSL_AD_DECODE_ERROR;
if (!tls12_check_peer_sigalg(ssl, &alert, signature_algorithm)) {
ssl3_send_alert(ssl, SSL3_AL_FATAL, alert);
return -1;
}
hs->new_session->peer_signature_algorithm = signature_algorithm;
} else if (!tls1_get_legacy_signature_algorithm(&signature_algorithm,
hs->peer_pubkey.get())) {
OPENSSL_PUT_ERROR(SSL, SSL_R_PEER_ERROR_UNSUPPORTED_CERTIFICATE_TYPE);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNSUPPORTED_CERTIFICATE);
return -1;
}
/* Parse and verify the signature. */
if (!CBS_get_u16_length_prefixed(&certificate_verify, &signature) ||
CBS_len(&certificate_verify) != 0) {
OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
return -1;
}
int sig_ok;
/* The SSL3 construction for CertificateVerify does not decompose into a
* single final digest and signature, and must be special-cased. */
if (ssl3_protocol_version(ssl) == SSL3_VERSION) {
uint8_t digest[EVP_MAX_MD_SIZE];
size_t digest_len;
if (!hs->transcript.GetSSL3CertVerifyHash(
digest, &digest_len, hs->new_session.get(), signature_algorithm)) {
return -1;
}
UniquePtr<EVP_PKEY_CTX> pctx(
EVP_PKEY_CTX_new(hs->peer_pubkey.get(), nullptr));
sig_ok = pctx &&
EVP_PKEY_verify_init(pctx.get()) &&
EVP_PKEY_verify(pctx.get(), CBS_data(&signature),
CBS_len(&signature), digest, digest_len);
} else {
sig_ok = ssl_public_key_verify(
ssl, CBS_data(&signature), CBS_len(&signature), signature_algorithm,
hs->peer_pubkey.get(), hs->transcript.buffer_data(),
hs->transcript.buffer_len());
}
#if defined(BORINGSSL_UNSAFE_FUZZER_MODE)
sig_ok = 1;
ERR_clear_error();
#endif
if (!sig_ok) {
OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_SIGNATURE);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECRYPT_ERROR);
return -1;
}
/* The handshake buffer is no longer necessary, and we may hash the current
* message.*/
hs->transcript.FreeBuffer();
if (!ssl_hash_current_message(hs)) {
return -1;
}
return 1;
}
/* ssl3_get_next_proto reads a Next Protocol Negotiation handshake message. It
* sets the next_proto member in s if found */
static int ssl3_get_next_proto(SSL_HANDSHAKE *hs) {
SSL *const ssl = hs->ssl;
int ret = ssl->method->ssl_get_message(ssl);
if (ret <= 0) {
return ret;
}
if (!ssl_check_message_type(ssl, SSL3_MT_NEXT_PROTO) ||
!ssl_hash_current_message(hs)) {
return -1;
}
CBS next_protocol, selected_protocol, padding;
CBS_init(&next_protocol, ssl->init_msg, ssl->init_num);
if (!CBS_get_u8_length_prefixed(&next_protocol, &selected_protocol) ||
!CBS_get_u8_length_prefixed(&next_protocol, &padding) ||
CBS_len(&next_protocol) != 0) {
OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
ssl3_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
return 0;
}
if (!CBS_stow(&selected_protocol, &ssl->s3->next_proto_negotiated,
&ssl->s3->next_proto_negotiated_len)) {
return 0;
}
return 1;
}
/* ssl3_get_channel_id reads and verifies a ClientID handshake message. */
static int ssl3_get_channel_id(SSL_HANDSHAKE *hs) {
SSL *const ssl = hs->ssl;
int msg_ret = ssl->method->ssl_get_message(ssl);
if (msg_ret <= 0) {
return msg_ret;
}
if (!ssl_check_message_type(ssl, SSL3_MT_CHANNEL_ID) ||
!tls1_verify_channel_id(hs) ||
!ssl_hash_current_message(hs)) {
return -1;
}
return 1;
}
static int ssl3_send_server_finished(SSL_HANDSHAKE *hs) {
SSL *const ssl = hs->ssl;
if (hs->ticket_expected) {
const SSL_SESSION *session;
UniquePtr<SSL_SESSION> session_copy;
if (ssl->session == NULL) {
/* Fix the timeout to measure from the ticket issuance time. */
ssl_session_rebase_time(ssl, hs->new_session.get());
session = hs->new_session.get();
} else {
/* We are renewing an existing session. Duplicate the session to adjust
* the timeout. */
session_copy = SSL_SESSION_dup(ssl->session, SSL_SESSION_INCLUDE_NONAUTH);
if (!session_copy) {
return -1;
}
ssl_session_rebase_time(ssl, session_copy.get());
session = session_copy.get();
}
ScopedCBB cbb;
CBB body, ticket;
if (!ssl->method->init_message(ssl, cbb.get(), &body,
SSL3_MT_NEW_SESSION_TICKET) ||
!CBB_add_u32(&body, session->timeout) ||
!CBB_add_u16_length_prefixed(&body, &ticket) ||
!ssl_encrypt_ticket(ssl, &ticket, session) ||
!ssl_add_message_cbb(ssl, cbb.get())) {
return -1;
}
}
if (!ssl->method->add_change_cipher_spec(ssl) ||
!tls1_change_cipher_state(hs, SSL3_CHANGE_CIPHER_SERVER_WRITE)) {
return -1;
}
return ssl3_send_finished(hs);
}
} // namespace bssl
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