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boringssl/ssl/handshake_server.cc
David Benjamin 8e7bbbab15 Use more scopers. 
Change-Id: I34dd0a57efd5435fcdc59a3c7b1ce806bc0cbb3e
Reviewed-on: https://boringssl-review.googlesource.com/21946
Reviewed-by: Steven Valdez <svaldez@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
2017-10-24 17:50:05 +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).
*
*/
/* ====================================================================
* 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 {
enum ssl_server_hs_state_t {
state_start_accept = 0,
state_read_client_hello,
state_select_certificate,
state_tls13,
state_select_parameters,
state_send_server_hello,
state_send_server_certificate,
state_send_server_key_exchange,
state_send_server_hello_done,
state_read_client_certificate,
state_verify_client_certificate,
state_read_client_key_exchange,
state_read_client_certificate_verify,
state_read_change_cipher_spec,
state_process_change_cipher_spec,
state_read_next_proto,
state_read_channel_id,
state_read_client_finished,
state_send_server_finished,
state_finish_server_handshake,
state_done,
};
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 = true;
ssl->s3->aead_write_ctx->SetVersionIfNullCipher(ssl->version);
// Handle FALLBACK_SCSV.
if (ssl_client_cipher_list_contains_cipher(client_hello,
SSL3_CK_FALLBACK_SCSV & 0xffff) &&
ssl_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 UniquePtr<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);
UniquePtr<STACK_OF(SSL_CIPHER)> sk(sk_SSL_CIPHER_new_null());
if (!sk) {
OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
return nullptr;
}
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);
return nullptr;
}
const SSL_CIPHER *c = SSL_get_cipher_by_value(cipher_suite);
if (c != NULL && !sk_SSL_CIPHER_push(sk.get(), c)) {
OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
return nullptr;
}
}
return sk;
}
// 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;
UniquePtr<STACK_OF(SSL_CIPHER)> client_pref =
ssl_parse_client_cipher_list(client_hello);
if (!client_pref) {
return nullptr;
}
if (ssl->options & SSL_OP_CIPHER_SERVER_PREFERENCE) {
prio = server_pref->ciphers;
in_group_flags = server_pref->in_group_flags;
allow = client_pref.get();
} else {
prio = client_pref.get();
in_group_flags = NULL;
allow = server_pref->ciphers;
}
uint32_t mask_k, mask_a;
ssl_get_compatible_server_ciphers(hs, &mask_k, &mask_a);
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) <= ssl_protocol_version(ssl) &&
ssl_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;
}
return sk_SSL_CIPHER_value(allow, cipher_index);
}
}
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.
return sk_SSL_CIPHER_value(allow, group_min);
}
}
return nullptr;
}
static enum ssl_hs_wait_t do_start_accept(SSL_HANDSHAKE *hs) {
ssl_do_info_callback(hs->ssl, SSL_CB_HANDSHAKE_START, 1);
hs->state = state_read_client_hello;
return ssl_hs_ok;
}
static enum ssl_hs_wait_t do_read_client_hello(SSL_HANDSHAKE *hs) {
SSL *const ssl = hs->ssl;
SSLMessage msg;
if (!ssl->method->get_message(ssl, &msg)) {
return ssl_hs_read_message;
}
if (!ssl_check_message_type(ssl, msg, SSL3_MT_CLIENT_HELLO)) {
return ssl_hs_error;
}
SSL_CLIENT_HELLO client_hello;
if (!ssl_client_hello_init(ssl, &client_hello, msg)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
return ssl_hs_error;
}
// Run the early callback.
if (ssl->ctx->select_certificate_cb != NULL) {
switch (ssl->ctx->select_certificate_cb(&client_hello)) {
case ssl_select_cert_retry:
return ssl_hs_certificate_selection_pending;
case ssl_select_cert_error:
// Connection rejected.
OPENSSL_PUT_ERROR(SSL, SSL_R_CONNECTION_REJECTED);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
return ssl_hs_error;
default:
/* fallthrough */;
}
}
// Freeze the version range after the early callback.
if (!ssl_get_version_range(ssl, &hs->min_version, &hs->max_version)) {
return ssl_hs_error;
}
uint8_t alert = SSL_AD_DECODE_ERROR;
if (!negotiate_version(hs, &alert, &client_hello)) {
ssl_send_alert(ssl, SSL3_AL_FATAL, alert);
return ssl_hs_error;
}
hs->client_version = client_hello.version;
if (client_hello.random_len != SSL3_RANDOM_SIZE) {
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
return ssl_hs_error;
}
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 ||
(ssl_protocol_version(ssl) >= TLS1_3_VERSION &&
client_hello.compression_methods_len != 1)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_COMPRESSION_LIST);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
return ssl_hs_error;
}
// TLS extensions.
if (!ssl_parse_clienthello_tlsext(hs, &client_hello)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_PARSE_TLSEXT);
return ssl_hs_error;
}
hs->state = state_select_certificate;
return ssl_hs_ok;
}
static enum ssl_hs_wait_t do_select_certificate(SSL_HANDSHAKE *hs) {
SSL *const ssl = hs->ssl;
SSLMessage msg;
if (!ssl->method->get_message(ssl, &msg)) {
return ssl_hs_read_message;
}
// 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);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
return ssl_hs_error;
}
if (rv < 0) {
return ssl_hs_x509_lookup;
}
}
if (!ssl_on_certificate_selected(hs)) {
return ssl_hs_error;
}
if (ssl_protocol_version(ssl) >= TLS1_3_VERSION) {
// Jump to the TLS 1.3 state machine.
hs->state = state_tls13;
return ssl_hs_ok;
}
SSL_CLIENT_HELLO client_hello;
if (!ssl_client_hello_init(ssl, &client_hello, msg)) {
return ssl_hs_error;
}
// 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);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
return ssl_hs_error;
}
hs->state = state_select_parameters;
return ssl_hs_ok;
}
static enum ssl_hs_wait_t do_tls13(SSL_HANDSHAKE *hs) {
enum ssl_hs_wait_t wait = tls13_server_handshake(hs);
if (wait == ssl_hs_ok) {
hs->state = state_finish_server_handshake;
return ssl_hs_ok;
}
return wait;
}
static enum ssl_hs_wait_t do_select_parameters(SSL_HANDSHAKE *hs) {
SSL *const ssl = hs->ssl;
SSLMessage msg;
if (!ssl->method->get_message(ssl, &msg)) {
return ssl_hs_read_message;
}
SSL_CLIENT_HELLO client_hello;
if (!ssl_client_hello_init(ssl, &client_hello, msg)) {
return ssl_hs_error;
}
// Determine whether we are doing session resumption.
UniquePtr<SSL_SESSION> session;
bool tickets_supported = false, renew_ticket = false;
enum ssl_hs_wait_t wait = ssl_get_prev_session(
ssl, &session, &tickets_supported, &renew_ticket, &client_hello);
if (wait != ssl_hs_ok) {
return wait;
}
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);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
return ssl_hs_error;
}
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 = true;
} else {
hs->ticket_expected = tickets_supported;
ssl_set_session(ssl, NULL);
if (!ssl_get_new_session(hs, 1 /* server */)) {
return ssl_hs_error;
}
// 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);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
return ssl_hs_error;
}
if (ssl->session == NULL) {
hs->new_session->cipher = hs->new_cipher;
// 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 = false;
}
// CertificateRequest may only be sent in certificate-based ciphers.
if (!ssl_cipher_uses_certificate_auth(hs->new_cipher)) {
hs->cert_request = false;
}
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)) {
ssl_send_alert(ssl, SSL3_AL_FATAL, alert);
return ssl_hs_error;
}
// Now that all parameters are known, initialize the handshake hash and hash
// the ClientHello.
if (!hs->transcript.InitHash(ssl_protocol_version(ssl), hs->new_cipher) ||
!ssl_hash_message(hs, msg)) {
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
return ssl_hs_error;
}
// Release the handshake buffer if client authentication isn't required.
if (!hs->cert_request) {
hs->transcript.FreeBuffer();
}
ssl->method->next_message(ssl);
hs->state = state_send_server_hello;
return ssl_hs_ok;
}
static enum ssl_hs_wait_t do_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 = false;
}
// 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 = false;
}
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 ssl_hs_error;
}
// 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 ssl_hs_error;
}
if (ssl->session != NULL) {
hs->state = state_send_server_finished;
} else {
hs->state = state_send_server_certificate;
}
return ssl_hs_ok;
}
static enum ssl_hs_wait_t do_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 ssl_hs_error;
}
if (!ssl_output_cert_chain(ssl)) {
return ssl_hs_error;
}
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 ssl_hs_error;
}
}
}
// 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 ssl_hs_error;
}
// 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 ssl_hs_error;
}
}
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);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
return ssl_hs_error;
}
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 ssl_hs_error;
}
} else {
assert(alg_k & SSL_kPSK);
}
if (!CBBFinishArray(cbb.get(), &hs->server_params)) {
return ssl_hs_error;
}
}
hs->state = state_send_server_key_exchange;
return ssl_hs_ok;
}
static enum ssl_hs_wait_t do_send_server_key_exchange(SSL_HANDSHAKE *hs) {
SSL *const ssl = hs->ssl;
if (hs->server_params.size() == 0) {
hs->state = state_send_server_hello_done;
return ssl_hs_ok;
}
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.size() < 2 * SSL3_RANDOM_SIZE ||
!CBB_add_bytes(&body, hs->server_params.data() + 2 * SSL3_RANDOM_SIZE,
hs->server_params.size() - 2 * SSL3_RANDOM_SIZE)) {
return ssl_hs_error;
}
// Add a signature.
if (ssl_cipher_uses_certificate_auth(hs->new_cipher)) {
if (!ssl_has_private_key(ssl)) {
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
return ssl_hs_error;
}
// Determine the signature algorithm.
uint16_t signature_algorithm;
if (!tls1_choose_signature_algorithm(hs, &signature_algorithm)) {
return ssl_hs_error;
}
if (ssl_protocol_version(ssl) >= TLS1_2_VERSION) {
if (!CBB_add_u16(&body, signature_algorithm)) {
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
return ssl_hs_error;
}
}
// 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 ssl_hs_error;
}
size_t sig_len;
switch (ssl_private_key_sign(hs, ptr, &sig_len, max_sig_len,
signature_algorithm, hs->server_params)) {
case ssl_private_key_success:
if (!CBB_did_write(&child, sig_len)) {
return ssl_hs_error;
}
break;
case ssl_private_key_failure:
return ssl_hs_error;
case ssl_private_key_retry:
return ssl_hs_private_key_operation;
}
}
if (!ssl_add_message_cbb(ssl, cbb.get())) {
return ssl_hs_error;
}
hs->server_params.Reset();
hs->state = state_send_server_hello_done;
return ssl_hs_ok;
}
static enum ssl_hs_wait_t do_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) ||
(ssl_protocol_version(ssl) >= TLS1_VERSION &&
!CBB_add_u8(&cert_types, TLS_CT_ECDSA_SIGN)) ||
(ssl_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 ssl_hs_error;
}
}
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 ssl_hs_error;
}
hs->state = state_read_client_certificate;
return ssl_hs_flush;
}
static enum ssl_hs_wait_t do_read_client_certificate(SSL_HANDSHAKE *hs) {
SSL *const ssl = hs->ssl;
if (!hs->cert_request) {
hs->state = state_verify_client_certificate;
return ssl_hs_ok;
}
SSLMessage msg;
if (!ssl->method->get_message(ssl, &msg)) {
return ssl_hs_read_message;
}
if (msg.type != SSL3_MT_CERTIFICATE) {
if (ssl->version == SSL3_VERSION &&
msg.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);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
return ssl_hs_error;
}
// 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;
hs->state = state_verify_client_certificate;
return ssl_hs_ok;
}
OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_MESSAGE);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE);
return ssl_hs_error;
}
if (!ssl_hash_message(hs, msg)) {
return ssl_hs_error;
}
CBS certificate_msg = msg.body;
uint8_t alert = SSL_AD_DECODE_ERROR;
UniquePtr<STACK_OF(CRYPTO_BUFFER)> chain;
if (!ssl_parse_cert_chain(&alert, &chain, &hs->peer_pubkey,
ssl->retain_only_sha256_of_client_certs
? hs->new_session->peer_sha256
: NULL,
&certificate_msg, ssl->ctx->pool)) {
ssl_send_alert(ssl, SSL3_AL_FATAL, alert);
return ssl_hs_error;
}
sk_CRYPTO_BUFFER_pop_free(hs->new_session->certs, CRYPTO_BUFFER_free);
hs->new_session->certs = chain.release();
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);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
return ssl_hs_error;
}
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);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
return ssl_hs_error;
}
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);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
return ssl_hs_error;
}
// 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;
} else if (ssl->retain_only_sha256_of_client_certs) {
// The hash will have been filled in.
hs->new_session->peer_sha256_valid = 1;
}
ssl->method->next_message(ssl);
hs->state = state_verify_client_certificate;
return ssl_hs_ok;
}
static enum ssl_hs_wait_t do_verify_client_certificate(SSL_HANDSHAKE *hs) {
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:
return ssl_hs_error;
case ssl_verify_retry:
return ssl_hs_certificate_verify;
}
}
hs->state = state_read_client_key_exchange;
return ssl_hs_ok;
}
static enum ssl_hs_wait_t do_read_client_key_exchange(SSL_HANDSHAKE *hs) {
SSL *const ssl = hs->ssl;
SSLMessage msg;
if (!ssl->method->get_message(ssl, &msg)) {
return ssl_hs_read_message;
}
if (!ssl_check_message_type(ssl, msg, SSL3_MT_CLIENT_KEY_EXCHANGE)) {
return ssl_hs_error;
}
CBS client_key_exchange = msg.body;
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);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
return ssl_hs_error;
}
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);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
return ssl_hs_error;
}
if (!CBS_strdup(&psk_identity, &hs->new_session->psk_identity)) {
OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
return ssl_hs_error;
}
}
// Depending on the key exchange method, compute |premaster_secret|.
Array<uint8_t> premaster_secret;
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);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
return ssl_hs_error;
}
} else {
encrypted_premaster_secret = client_key_exchange;
}
// Allocate a buffer large enough for an RSA decryption.
Array<uint8_t> decrypt_buf;
if (!decrypt_buf.Init(EVP_PKEY_size(hs->local_pubkey.get()))) {
return ssl_hs_error;
}
// 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.data(), &decrypt_len,
decrypt_buf.size(),
encrypted_premaster_secret)) {
case ssl_private_key_success:
break;
case ssl_private_key_failure:
return ssl_hs_error;
case ssl_private_key_retry:
return ssl_hs_private_key_operation;
}
if (decrypt_len != decrypt_buf.size()) {
OPENSSL_PUT_ERROR(SSL, SSL_R_DECRYPTION_FAILED);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECRYPT_ERROR);
return ssl_hs_error;
}
// Prepare a random premaster, to be used on invalid padding. See RFC 5246,
// section 7.4.7.1.
if (!premaster_secret.Init(SSL_MAX_MASTER_KEY_LENGTH) ||
!RAND_bytes(premaster_secret.data(), premaster_secret.size())) {
return ssl_hs_error;
}
// The smallest padded premaster is 11 bytes of overhead. Small keys are
// publicly invalid.
if (decrypt_len < 11 + premaster_secret.size()) {
OPENSSL_PUT_ERROR(SSL, SSL_R_DECRYPTION_FAILED);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECRYPT_ERROR);
return ssl_hs_error;
}
// Check the padding. See RFC 3447, section 7.2.2.
size_t padding_len = decrypt_len - premaster_secret.size();
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.size(); i++) {
premaster_secret[i] = constant_time_select_8(
good, decrypt_buf[padding_len + i], premaster_secret[i]);
}
} 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);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
return ssl_hs_error;
}
// Compute the premaster.
uint8_t alert = SSL_AD_DECODE_ERROR;
if (!hs->key_share->Finish(&premaster_secret, &alert, peer_key)) {
ssl_send_alert(ssl, SSL3_AL_FATAL, alert);
return ssl_hs_error;
}
// 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);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
return ssl_hs_error;
}
// 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);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
return ssl_hs_error;
}
// 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);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
return ssl_hs_error;
} else if (psk_len == 0) {
// PSK related to the given identity not found.
OPENSSL_PUT_ERROR(SSL, SSL_R_PSK_IDENTITY_NOT_FOUND);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNKNOWN_PSK_IDENTITY);
return ssl_hs_error;
}
if (alg_k & SSL_kPSK) {
// In plain PSK, other_secret is a block of 0s with the same length as the
// pre-shared key.
if (!premaster_secret.Init(psk_len)) {
return ssl_hs_error;
}
OPENSSL_memset(premaster_secret.data(), 0, premaster_secret.size());
}
ScopedCBB new_premaster;
CBB child;
if (!CBB_init(new_premaster.get(),
2 + psk_len + 2 + premaster_secret.size()) ||
!CBB_add_u16_length_prefixed(new_premaster.get(), &child) ||
!CBB_add_bytes(&child, premaster_secret.data(),
premaster_secret.size()) ||
!CBB_add_u16_length_prefixed(new_premaster.get(), &child) ||
!CBB_add_bytes(&child, psk, psk_len) ||
!CBBFinishArray(new_premaster.get(), &premaster_secret)) {
OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
return ssl_hs_error;
}
}
if (!ssl_hash_message(hs, msg)) {
return ssl_hs_error;
}
// Compute the master secret.
hs->new_session->master_key_length = tls1_generate_master_secret(
hs, hs->new_session->master_key, premaster_secret.data(),
premaster_secret.size());
if (hs->new_session->master_key_length == 0) {
return ssl_hs_error;
}
hs->new_session->extended_master_secret = hs->extended_master_secret;
ssl->method->next_message(ssl);
hs->state = state_read_client_certificate_verify;
return ssl_hs_ok;
}
static enum ssl_hs_wait_t do_read_client_certificate_verify(SSL_HANDSHAKE *hs) {
SSL *const ssl = hs->ssl;
// 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();
hs->state = state_read_change_cipher_spec;
return ssl_hs_ok;
}
SSLMessage msg;
if (!ssl->method->get_message(ssl, &msg)) {
return ssl_hs_read_message;
}
if (!ssl_check_message_type(ssl, msg, SSL3_MT_CERTIFICATE_VERIFY)) {
return ssl_hs_error;
}
CBS certificate_verify = msg.body, signature;
// Determine the signature algorithm.
uint16_t signature_algorithm = 0;
if (ssl_protocol_version(ssl) >= TLS1_2_VERSION) {
if (!CBS_get_u16(&certificate_verify, &signature_algorithm)) {
OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
return ssl_hs_error;
}
uint8_t alert = SSL_AD_DECODE_ERROR;
if (!tls12_check_peer_sigalg(ssl, &alert, signature_algorithm)) {
ssl_send_alert(ssl, SSL3_AL_FATAL, alert);
return ssl_hs_error;
}
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);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_UNSUPPORTED_CERTIFICATE);
return ssl_hs_error;
}
// 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);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
return ssl_hs_error;
}
bool sig_ok;
// The SSL3 construction for CertificateVerify does not decompose into a
// single final digest and signature, and must be special-cased.
if (ssl_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 ssl_hs_error;
}
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, signature, signature_algorithm,
hs->peer_pubkey.get(), hs->transcript.buffer());
}
#if defined(BORINGSSL_UNSAFE_FUZZER_MODE)
sig_ok = true;
ERR_clear_error();
#endif
if (!sig_ok) {
OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_SIGNATURE);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECRYPT_ERROR);
return ssl_hs_error;
}
// The handshake buffer is no longer necessary, and we may hash the current
// message.
hs->transcript.FreeBuffer();
if (!ssl_hash_message(hs, msg)) {
return ssl_hs_error;
}
ssl->method->next_message(ssl);
hs->state = state_read_change_cipher_spec;
return ssl_hs_ok;
}
static enum ssl_hs_wait_t do_read_change_cipher_spec(SSL_HANDSHAKE *hs) {
hs->state = state_process_change_cipher_spec;
return ssl_hs_read_change_cipher_spec;
}
static enum ssl_hs_wait_t do_process_change_cipher_spec(SSL_HANDSHAKE *hs) {
if (!tls1_change_cipher_state(hs, evp_aead_open)) {
return ssl_hs_error;
}
hs->state = state_read_next_proto;
return ssl_hs_ok;
}
static enum ssl_hs_wait_t do_read_next_proto(SSL_HANDSHAKE *hs) {
SSL *const ssl = hs->ssl;
if (!hs->next_proto_neg_seen) {
hs->state = state_read_channel_id;
return ssl_hs_ok;
}
SSLMessage msg;
if (!ssl->method->get_message(ssl, &msg)) {
return ssl_hs_read_message;
}
if (!ssl_check_message_type(ssl, msg, SSL3_MT_NEXT_PROTO) ||
!ssl_hash_message(hs, msg)) {
return ssl_hs_error;
}
CBS next_protocol = msg.body, selected_protocol, padding;
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);
ssl_send_alert(ssl, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
return ssl_hs_error;
}
if (!ssl->s3->next_proto_negotiated.CopyFrom(selected_protocol)) {
return ssl_hs_error;
}
ssl->method->next_message(ssl);
hs->state = state_read_channel_id;
return ssl_hs_ok;
}
static enum ssl_hs_wait_t do_read_channel_id(SSL_HANDSHAKE *hs) {
SSL *const ssl = hs->ssl;
if (!ssl->s3->tlsext_channel_id_valid) {
hs->state = state_read_client_finished;
return ssl_hs_ok;
}
SSLMessage msg;
if (!ssl->method->get_message(ssl, &msg)) {
return ssl_hs_read_message;
}
if (!ssl_check_message_type(ssl, msg, SSL3_MT_CHANNEL_ID) ||
!tls1_verify_channel_id(hs, msg) ||
!ssl_hash_message(hs, msg)) {
return ssl_hs_error;
}
ssl->method->next_message(ssl);
hs->state = state_read_client_finished;
return ssl_hs_ok;
}
static enum ssl_hs_wait_t do_read_client_finished(SSL_HANDSHAKE *hs) {
SSL *const ssl = hs->ssl;
enum ssl_hs_wait_t wait = ssl_get_finished(hs);
if (wait != ssl_hs_ok) {
return wait;
}
if (ssl->session != NULL) {
hs->state = state_finish_server_handshake;
} else {
hs->state = state_send_server_finished;
}
// 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 &&
!tls1_record_handshake_hashes_for_channel_id(hs)) {
return ssl_hs_error;
}
return ssl_hs_ok;
}
static enum ssl_hs_wait_t do_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 ssl_hs_error;
}
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 ssl_hs_error;
}
}
if (!ssl->method->add_change_cipher_spec(ssl) ||
!tls1_change_cipher_state(hs, evp_aead_seal) ||
!ssl_send_finished(hs)) {
return ssl_hs_error;
}
if (ssl->session != NULL) {
hs->state = state_read_change_cipher_spec;
} else {
hs->state = state_finish_server_handshake;
}
return ssl_hs_flush;
}
static enum ssl_hs_wait_t do_finish_server_handshake(SSL_HANDSHAKE *hs) {
SSL *const ssl = hs->ssl;
ssl->method->on_handshake_complete(ssl);
// 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());
}
if (ssl->session != NULL) {
SSL_SESSION_up_ref(ssl->session);
ssl->s3->established_session.reset(ssl->session);
} else {
ssl->s3->established_session = std::move(hs->new_session);
ssl->s3->established_session->not_resumable = 0;
}
hs->handshake_finalized = true;
ssl->s3->initial_handshake_complete = true;
ssl_update_cache(hs, SSL_SESS_CACHE_SERVER);
hs->state = state_done;
return ssl_hs_ok;
}
enum ssl_hs_wait_t ssl_server_handshake(SSL_HANDSHAKE *hs) {
while (hs->state != state_done) {
enum ssl_hs_wait_t ret = ssl_hs_error;
enum ssl_server_hs_state_t state =
static_cast<enum ssl_server_hs_state_t>(hs->state);
switch (state) {
case state_start_accept:
ret = do_start_accept(hs);
break;
case state_read_client_hello:
ret = do_read_client_hello(hs);
break;
case state_select_certificate:
ret = do_select_certificate(hs);
break;
case state_tls13:
ret = do_tls13(hs);
break;
case state_select_parameters:
ret = do_select_parameters(hs);
break;
case state_send_server_hello:
ret = do_send_server_hello(hs);
break;
case state_send_server_certificate:
ret = do_send_server_certificate(hs);
break;
case state_send_server_key_exchange:
ret = do_send_server_key_exchange(hs);
break;
case state_send_server_hello_done:
ret = do_send_server_hello_done(hs);
break;
case state_read_client_certificate:
ret = do_read_client_certificate(hs);
break;
case state_verify_client_certificate:
ret = do_verify_client_certificate(hs);
break;
case state_read_client_key_exchange:
ret = do_read_client_key_exchange(hs);
break;
case state_read_client_certificate_verify:
ret = do_read_client_certificate_verify(hs);
break;
case state_read_change_cipher_spec:
ret = do_read_change_cipher_spec(hs);
break;
case state_process_change_cipher_spec:
ret = do_process_change_cipher_spec(hs);
break;
case state_read_next_proto:
ret = do_read_next_proto(hs);
break;
case state_read_channel_id:
ret = do_read_channel_id(hs);
break;
case state_read_client_finished:
ret = do_read_client_finished(hs);
break;
case state_send_server_finished:
ret = do_send_server_finished(hs);
break;
case state_finish_server_handshake:
ret = do_finish_server_handshake(hs);
break;
case state_done:
ret = ssl_hs_ok;
break;
}
if (hs->state != state) {
ssl_do_info_callback(hs->ssl, SSL_CB_ACCEPT_LOOP, 1);
}
if (ret != ssl_hs_ok) {
return ret;
}
}
ssl_do_info_callback(hs->ssl, SSL_CB_HANDSHAKE_DONE, 1);
return ssl_hs_ok;
}
const char *ssl_server_handshake_state(SSL_HANDSHAKE *hs) {
enum ssl_server_hs_state_t state =
static_cast<enum ssl_server_hs_state_t>(hs->state);
switch (state) {
case state_start_accept:
return "TLS server start_accept";
case state_read_client_hello:
return "TLS server read_client_hello";
case state_select_certificate:
return "TLS server select_certificate";
case state_tls13:
return tls13_server_handshake_state(hs);
case state_select_parameters:
return "TLS server select_parameters";
case state_send_server_hello:
return "TLS server send_server_hello";
case state_send_server_certificate:
return "TLS server send_server_certificate";
case state_send_server_key_exchange:
return "TLS server send_server_key_exchange";
case state_send_server_hello_done:
return "TLS server send_server_hello_done";
case state_read_client_certificate:
return "TLS server read_client_certificate";
case state_verify_client_certificate:
return "TLS server verify_client_certificate";
case state_read_client_key_exchange:
return "TLS server read_client_key_exchange";
case state_read_client_certificate_verify:
return "TLS server read_client_certificate_verify";
case state_read_change_cipher_spec:
return "TLS server read_change_cipher_spec";
case state_process_change_cipher_spec:
return "TLS server process_change_cipher_spec";
case state_read_next_proto:
return "TLS server read_next_proto";
case state_read_channel_id:
return "TLS server read_channel_id";
case state_read_client_finished:
return "TLS server read_client_finished";
case state_send_server_finished:
return "TLS server send_server_finished";
case state_finish_server_handshake:
return "TLS server finish_server_handshake";
case state_done:
return "TLS server done";
}
return "TLS server unknown";
}
}
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