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mbedtls/library/ssl_tls12_server.c
Valerio Setti 6835b4a6ed tls: always zeroize buffer on exit 
Signed-off-by: Valerio Setti <valerio.setti@nordicsemi.no>
2023-06-22 09:06:31 +02:00

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/*
* TLS server-side functions
*
* Copyright The Mbed TLS Contributors
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "common.h"
#if defined(MBEDTLS_SSL_SRV_C) && defined(MBEDTLS_SSL_PROTO_TLS1_2)
#include "mbedtls/platform.h"
#include "mbedtls/ssl.h"
#include "ssl_misc.h"
#include "mbedtls/debug.h"
#include "mbedtls/error.h"
#include "mbedtls/platform_util.h"
#include "constant_time_internal.h"
#include "mbedtls/constant_time.h"
#include <string.h>
#if defined(MBEDTLS_USE_PSA_CRYPTO)
#define PSA_TO_MBEDTLS_ERR(status) PSA_TO_MBEDTLS_ERR_LIST(status, \
psa_to_ssl_errors, \
psa_generic_status_to_mbedtls)
#endif
#if defined(MBEDTLS_ECP_C)
#include "mbedtls/ecp.h"
#endif
#if defined(MBEDTLS_HAVE_TIME)
#include "mbedtls/platform_time.h"
#endif
#if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY)
int mbedtls_ssl_set_client_transport_id(mbedtls_ssl_context *ssl,
const unsigned char *info,
size_t ilen)
{
if (ssl->conf->endpoint != MBEDTLS_SSL_IS_SERVER) {
return MBEDTLS_ERR_SSL_BAD_INPUT_DATA;
}
mbedtls_free(ssl->cli_id);
if ((ssl->cli_id = mbedtls_calloc(1, ilen)) == NULL) {
return MBEDTLS_ERR_SSL_ALLOC_FAILED;
}
memcpy(ssl->cli_id, info, ilen);
ssl->cli_id_len = ilen;
return 0;
}
void mbedtls_ssl_conf_dtls_cookies(mbedtls_ssl_config *conf,
mbedtls_ssl_cookie_write_t *f_cookie_write,
mbedtls_ssl_cookie_check_t *f_cookie_check,
void *p_cookie)
{
conf->f_cookie_write = f_cookie_write;
conf->f_cookie_check = f_cookie_check;
conf->p_cookie = p_cookie;
}
#endif /* MBEDTLS_SSL_DTLS_HELLO_VERIFY */
#if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED)
MBEDTLS_CHECK_RETURN_CRITICAL
static int ssl_conf_has_psk_or_cb(mbedtls_ssl_config const *conf)
{
if (conf->f_psk != NULL) {
return 1;
}
if (conf->psk_identity_len == 0 || conf->psk_identity == NULL) {
return 0;
}
#if defined(MBEDTLS_USE_PSA_CRYPTO)
if (!mbedtls_svc_key_id_is_null(conf->psk_opaque)) {
return 1;
}
#endif /* MBEDTLS_USE_PSA_CRYPTO */
if (conf->psk != NULL && conf->psk_len != 0) {
return 1;
}
return 0;
}
#endif /* MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED */
MBEDTLS_CHECK_RETURN_CRITICAL
static int ssl_parse_renegotiation_info(mbedtls_ssl_context *ssl,
const unsigned char *buf,
size_t len)
{
#if defined(MBEDTLS_SSL_RENEGOTIATION)
if (ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE) {
/* Check verify-data in constant-time. The length OTOH is no secret */
if (len != 1 + ssl->verify_data_len ||
buf[0] != ssl->verify_data_len ||
mbedtls_ct_memcmp(buf + 1, ssl->peer_verify_data,
ssl->verify_data_len) != 0) {
MBEDTLS_SSL_DEBUG_MSG(1, ("non-matching renegotiation info"));
mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE);
return MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE;
}
} else
#endif /* MBEDTLS_SSL_RENEGOTIATION */
{
if (len != 1 || buf[0] != 0x0) {
MBEDTLS_SSL_DEBUG_MSG(1, ("non-zero length renegotiation info"));
mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE);
return MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE;
}
ssl->secure_renegotiation = MBEDTLS_SSL_SECURE_RENEGOTIATION;
}
return 0;
}
#if defined(MBEDTLS_PK_CAN_ECDH) || defined(MBEDTLS_PK_CAN_ECDSA_SOME) || \
defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
/*
* Function for parsing a supported groups (TLS 1.3) or supported elliptic
* curves (TLS 1.2) extension.
*
* The "extension_data" field of a supported groups extension contains a
* "NamedGroupList" value (TLS 1.3 RFC8446):
* enum {
* secp256r1(0x0017), secp384r1(0x0018), secp521r1(0x0019),
* x25519(0x001D), x448(0x001E),
* ffdhe2048(0x0100), ffdhe3072(0x0101), ffdhe4096(0x0102),
* ffdhe6144(0x0103), ffdhe8192(0x0104),
* ffdhe_private_use(0x01FC..0x01FF),
* ecdhe_private_use(0xFE00..0xFEFF),
* (0xFFFF)
* } NamedGroup;
* struct {
* NamedGroup named_group_list<2..2^16-1>;
* } NamedGroupList;
*
* The "extension_data" field of a supported elliptic curves extension contains
* a "NamedCurveList" value (TLS 1.2 RFC 8422):
* enum {
* deprecated(1..22),
* secp256r1 (23), secp384r1 (24), secp521r1 (25),
* x25519(29), x448(30),
* reserved (0xFE00..0xFEFF),
* deprecated(0xFF01..0xFF02),
* (0xFFFF)
* } NamedCurve;
* struct {
* NamedCurve named_curve_list<2..2^16-1>
* } NamedCurveList;
*
* The TLS 1.3 supported groups extension was defined to be a compatible
* generalization of the TLS 1.2 supported elliptic curves extension. They both
* share the same extension identifier.
*
* DHE groups are not supported yet.
*/
MBEDTLS_CHECK_RETURN_CRITICAL
static int ssl_parse_supported_groups_ext(mbedtls_ssl_context *ssl,
const unsigned char *buf,
size_t len)
{
size_t list_size, our_size;
const unsigned char *p;
uint16_t *curves_tls_id;
if (len < 2) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message"));
mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR);
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
list_size = ((buf[0] << 8) | (buf[1]));
if (list_size + 2 != len ||
list_size % 2 != 0) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message"));
mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR);
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
/* Should never happen unless client duplicates the extension */
if (ssl->handshake->curves_tls_id != NULL) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message"));
mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER);
return MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER;
}
/* Don't allow our peer to make us allocate too much memory,
* and leave room for a final 0 */
our_size = list_size / 2 + 1;
if (our_size > MBEDTLS_ECP_DP_MAX) {
our_size = MBEDTLS_ECP_DP_MAX;
}
if ((curves_tls_id = mbedtls_calloc(our_size,
sizeof(*curves_tls_id))) == NULL) {
mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_INTERNAL_ERROR);
return MBEDTLS_ERR_SSL_ALLOC_FAILED;
}
ssl->handshake->curves_tls_id = curves_tls_id;
p = buf + 2;
while (list_size > 0 && our_size > 1) {
uint16_t curr_tls_id = MBEDTLS_GET_UINT16_BE(p, 0);
if (mbedtls_ssl_get_ecp_group_id_from_tls_id(curr_tls_id) !=
MBEDTLS_ECP_DP_NONE) {
*curves_tls_id++ = curr_tls_id;
our_size--;
}
list_size -= 2;
p += 2;
}
return 0;
}
MBEDTLS_CHECK_RETURN_CRITICAL
static int ssl_parse_supported_point_formats(mbedtls_ssl_context *ssl,
const unsigned char *buf,
size_t len)
{
size_t list_size;
const unsigned char *p;
if (len == 0 || (size_t) (buf[0] + 1) != len) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message"));
mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR);
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
list_size = buf[0];
p = buf + 1;
while (list_size > 0) {
if (p[0] == MBEDTLS_ECP_PF_UNCOMPRESSED ||
p[0] == MBEDTLS_ECP_PF_COMPRESSED) {
#if !defined(MBEDTLS_USE_PSA_CRYPTO) && defined(MBEDTLS_ECDH_C)
ssl->handshake->ecdh_ctx.point_format = p[0];
#endif /* !MBEDTLS_USE_PSA_CRYPTO && MBEDTLS_ECDH_C */
#if !defined(MBEDTLS_USE_PSA_CRYPTO) && \
defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
mbedtls_ecjpake_set_point_format(&ssl->handshake->ecjpake_ctx,
p[0]);
#endif /* !MBEDTLS_USE_PSA_CRYPTO && MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
MBEDTLS_SSL_DEBUG_MSG(4, ("point format selected: %d", p[0]));
return 0;
}
list_size--;
p++;
}
return 0;
}
#endif /* MBEDTLS_PK_CAN_ECDH || MBEDTLS_PK_CAN_ECDSA_SOME ||
MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
#if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
MBEDTLS_CHECK_RETURN_CRITICAL
static int ssl_parse_ecjpake_kkpp(mbedtls_ssl_context *ssl,
const unsigned char *buf,
size_t len)
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
#if defined(MBEDTLS_USE_PSA_CRYPTO)
if (ssl->handshake->psa_pake_ctx_is_ok != 1)
#else
if (mbedtls_ecjpake_check(&ssl->handshake->ecjpake_ctx) != 0)
#endif /* MBEDTLS_USE_PSA_CRYPTO */
{
MBEDTLS_SSL_DEBUG_MSG(3, ("skip ecjpake kkpp extension"));
return 0;
}
#if defined(MBEDTLS_USE_PSA_CRYPTO)
if ((ret = mbedtls_psa_ecjpake_read_round(
&ssl->handshake->psa_pake_ctx, buf, len,
MBEDTLS_ECJPAKE_ROUND_ONE)) != 0) {
psa_destroy_key(ssl->handshake->psa_pake_password);
psa_pake_abort(&ssl->handshake->psa_pake_ctx);
MBEDTLS_SSL_DEBUG_RET(1, "psa_pake_input round one", ret);
mbedtls_ssl_send_alert_message(
ssl,
MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE);
return ret;
}
#else
if ((ret = mbedtls_ecjpake_read_round_one(&ssl->handshake->ecjpake_ctx,
buf, len)) != 0) {
MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ecjpake_read_round_one", ret);
mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER);
return ret;
}
#endif /* MBEDTLS_USE_PSA_CRYPTO */
/* Only mark the extension as OK when we're sure it is */
ssl->handshake->cli_exts |= MBEDTLS_TLS_EXT_ECJPAKE_KKPP_OK;
return 0;
}
#endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
#if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
MBEDTLS_CHECK_RETURN_CRITICAL
static int ssl_parse_max_fragment_length_ext(mbedtls_ssl_context *ssl,
const unsigned char *buf,
size_t len)
{
if (len != 1 || buf[0] >= MBEDTLS_SSL_MAX_FRAG_LEN_INVALID) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message"));
mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER);
return MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER;
}
ssl->session_negotiate->mfl_code = buf[0];
return 0;
}
#endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */
#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
MBEDTLS_CHECK_RETURN_CRITICAL
static int ssl_parse_cid_ext(mbedtls_ssl_context *ssl,
const unsigned char *buf,
size_t len)
{
size_t peer_cid_len;
/* CID extension only makes sense in DTLS */
if (ssl->conf->transport != MBEDTLS_SSL_TRANSPORT_DATAGRAM) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message"));
mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER);
return MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER;
}
/*
* struct {
* opaque cid<0..2^8-1>;
* } ConnectionId;
*/
if (len < 1) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message"));
mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR);
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
peer_cid_len = *buf++;
len--;
if (len != peer_cid_len) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message"));
mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR);
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
/* Ignore CID if the user has disabled its use. */
if (ssl->negotiate_cid == MBEDTLS_SSL_CID_DISABLED) {
/* Leave ssl->handshake->cid_in_use in its default
* value of MBEDTLS_SSL_CID_DISABLED. */
MBEDTLS_SSL_DEBUG_MSG(3, ("Client sent CID extension, but CID disabled"));
return 0;
}
if (peer_cid_len > MBEDTLS_SSL_CID_OUT_LEN_MAX) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message"));
mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER);
return MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER;
}
ssl->handshake->cid_in_use = MBEDTLS_SSL_CID_ENABLED;
ssl->handshake->peer_cid_len = (uint8_t) peer_cid_len;
memcpy(ssl->handshake->peer_cid, buf, peer_cid_len);
MBEDTLS_SSL_DEBUG_MSG(3, ("Use of CID extension negotiated"));
MBEDTLS_SSL_DEBUG_BUF(3, "Client CID", buf, peer_cid_len);
return 0;
}
#endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */
#if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
MBEDTLS_CHECK_RETURN_CRITICAL
static int ssl_parse_encrypt_then_mac_ext(mbedtls_ssl_context *ssl,
const unsigned char *buf,
size_t len)
{
if (len != 0) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message"));
mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR);
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
((void) buf);
if (ssl->conf->encrypt_then_mac == MBEDTLS_SSL_ETM_ENABLED) {
ssl->session_negotiate->encrypt_then_mac = MBEDTLS_SSL_ETM_ENABLED;
}
return 0;
}
#endif /* MBEDTLS_SSL_ENCRYPT_THEN_MAC */
#if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
MBEDTLS_CHECK_RETURN_CRITICAL
static int ssl_parse_extended_ms_ext(mbedtls_ssl_context *ssl,
const unsigned char *buf,
size_t len)
{
if (len != 0) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message"));
mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR);
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
((void) buf);
if (ssl->conf->extended_ms == MBEDTLS_SSL_EXTENDED_MS_ENABLED) {
ssl->handshake->extended_ms = MBEDTLS_SSL_EXTENDED_MS_ENABLED;
}
return 0;
}
#endif /* MBEDTLS_SSL_EXTENDED_MASTER_SECRET */
#if defined(MBEDTLS_SSL_SESSION_TICKETS)
MBEDTLS_CHECK_RETURN_CRITICAL
static int ssl_parse_session_ticket_ext(mbedtls_ssl_context *ssl,
unsigned char *buf,
size_t len)
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
mbedtls_ssl_session session;
mbedtls_ssl_session_init(&session);
if (ssl->conf->f_ticket_parse == NULL ||
ssl->conf->f_ticket_write == NULL) {
return 0;
}
/* Remember the client asked us to send a new ticket */
ssl->handshake->new_session_ticket = 1;
MBEDTLS_SSL_DEBUG_MSG(3, ("ticket length: %" MBEDTLS_PRINTF_SIZET, len));
if (len == 0) {
return 0;
}
#if defined(MBEDTLS_SSL_RENEGOTIATION)
if (ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE) {
MBEDTLS_SSL_DEBUG_MSG(3, ("ticket rejected: renegotiating"));
return 0;
}
#endif /* MBEDTLS_SSL_RENEGOTIATION */
/*
* Failures are ok: just ignore the ticket and proceed.
*/
if ((ret = ssl->conf->f_ticket_parse(ssl->conf->p_ticket, &session,
buf, len)) != 0) {
mbedtls_ssl_session_free(&session);
if (ret == MBEDTLS_ERR_SSL_INVALID_MAC) {
MBEDTLS_SSL_DEBUG_MSG(3, ("ticket is not authentic"));
} else if (ret == MBEDTLS_ERR_SSL_SESSION_TICKET_EXPIRED) {
MBEDTLS_SSL_DEBUG_MSG(3, ("ticket is expired"));
} else {
MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_ticket_parse", ret);
}
return 0;
}
/*
* Keep the session ID sent by the client, since we MUST send it back to
* inform them we're accepting the ticket (RFC 5077 section 3.4)
*/
session.id_len = ssl->session_negotiate->id_len;
memcpy(&session.id, ssl->session_negotiate->id, session.id_len);
mbedtls_ssl_session_free(ssl->session_negotiate);
memcpy(ssl->session_negotiate, &session, sizeof(mbedtls_ssl_session));
/* Zeroize instead of free as we copied the content */
mbedtls_platform_zeroize(&session, sizeof(mbedtls_ssl_session));
MBEDTLS_SSL_DEBUG_MSG(3, ("session successfully restored from ticket"));
ssl->handshake->resume = 1;
/* Don't send a new ticket after all, this one is OK */
ssl->handshake->new_session_ticket = 0;
return 0;
}
#endif /* MBEDTLS_SSL_SESSION_TICKETS */
#if defined(MBEDTLS_SSL_DTLS_SRTP)
MBEDTLS_CHECK_RETURN_CRITICAL
static int ssl_parse_use_srtp_ext(mbedtls_ssl_context *ssl,
const unsigned char *buf,
size_t len)
{
mbedtls_ssl_srtp_profile client_protection = MBEDTLS_TLS_SRTP_UNSET;
size_t i, j;
size_t profile_length;
uint16_t mki_length;
/*! 2 bytes for profile length and 1 byte for mki len */
const size_t size_of_lengths = 3;
/* If use_srtp is not configured, just ignore the extension */
if ((ssl->conf->transport != MBEDTLS_SSL_TRANSPORT_DATAGRAM) ||
(ssl->conf->dtls_srtp_profile_list == NULL) ||
(ssl->conf->dtls_srtp_profile_list_len == 0)) {
return 0;
}
/* RFC5764 section 4.1.1
* uint8 SRTPProtectionProfile[2];
*
* struct {
* SRTPProtectionProfiles SRTPProtectionProfiles;
* opaque srtp_mki<0..255>;
* } UseSRTPData;
* SRTPProtectionProfile SRTPProtectionProfiles<2..2^16-1>;
*/
/*
* Min length is 5: at least one protection profile(2 bytes)
* and length(2 bytes) + srtp_mki length(1 byte)
* Check here that we have at least 2 bytes of protection profiles length
* and one of srtp_mki length
*/
if (len < size_of_lengths) {
mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR);
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
ssl->dtls_srtp_info.chosen_dtls_srtp_profile = MBEDTLS_TLS_SRTP_UNSET;
/* first 2 bytes are protection profile length(in bytes) */
profile_length = (buf[0] << 8) | buf[1];
buf += 2;
/* The profile length cannot be bigger than input buffer size - lengths fields */
if (profile_length > len - size_of_lengths ||
profile_length % 2 != 0) { /* profiles are 2 bytes long, so the length must be even */
mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR);
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
/*
* parse the extension list values are defined in
* http://www.iana.org/assignments/srtp-protection/srtp-protection.xhtml
*/
for (j = 0; j < profile_length; j += 2) {
uint16_t protection_profile_value = buf[j] << 8 | buf[j + 1];
client_protection = mbedtls_ssl_check_srtp_profile_value(protection_profile_value);
if (client_protection != MBEDTLS_TLS_SRTP_UNSET) {
MBEDTLS_SSL_DEBUG_MSG(3, ("found srtp profile: %s",
mbedtls_ssl_get_srtp_profile_as_string(
client_protection)));
} else {
continue;
}
/* check if suggested profile is in our list */
for (i = 0; i < ssl->conf->dtls_srtp_profile_list_len; i++) {
if (client_protection == ssl->conf->dtls_srtp_profile_list[i]) {
ssl->dtls_srtp_info.chosen_dtls_srtp_profile = ssl->conf->dtls_srtp_profile_list[i];
MBEDTLS_SSL_DEBUG_MSG(3, ("selected srtp profile: %s",
mbedtls_ssl_get_srtp_profile_as_string(
client_protection)));
break;
}
}
if (ssl->dtls_srtp_info.chosen_dtls_srtp_profile != MBEDTLS_TLS_SRTP_UNSET) {
break;
}
}
buf += profile_length; /* buf points to the mki length */
mki_length = *buf;
buf++;
if (mki_length > MBEDTLS_TLS_SRTP_MAX_MKI_LENGTH ||
mki_length + profile_length + size_of_lengths != len) {
mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR);
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
/* Parse the mki only if present and mki is supported locally */
if (ssl->conf->dtls_srtp_mki_support == MBEDTLS_SSL_DTLS_SRTP_MKI_SUPPORTED &&
mki_length > 0) {
ssl->dtls_srtp_info.mki_len = mki_length;
memcpy(ssl->dtls_srtp_info.mki_value, buf, mki_length);
MBEDTLS_SSL_DEBUG_BUF(3, "using mki", ssl->dtls_srtp_info.mki_value,
ssl->dtls_srtp_info.mki_len);
}
return 0;
}
#endif /* MBEDTLS_SSL_DTLS_SRTP */
/*
* Auxiliary functions for ServerHello parsing and related actions
*/
#if defined(MBEDTLS_X509_CRT_PARSE_C)
/*
* Return 0 if the given key uses one of the acceptable curves, -1 otherwise
*/
#if defined(MBEDTLS_PK_CAN_ECDSA_SOME)
MBEDTLS_CHECK_RETURN_CRITICAL
static int ssl_check_key_curve(mbedtls_pk_context *pk,
uint16_t *curves_tls_id)
{
uint16_t *curr_tls_id = curves_tls_id;
mbedtls_ecp_group_id grp_id = mbedtls_pk_ec_ro(*pk)->grp.id;
mbedtls_ecp_group_id curr_grp_id;
while (*curr_tls_id != 0) {
curr_grp_id = mbedtls_ssl_get_ecp_group_id_from_tls_id(*curr_tls_id);
if (curr_grp_id == grp_id) {
return 0;
}
curr_tls_id++;
}
return -1;
}
#endif /* MBEDTLS_PK_CAN_ECDSA_SOME */
/*
* Try picking a certificate for this ciphersuite,
* return 0 on success and -1 on failure.
*/
MBEDTLS_CHECK_RETURN_CRITICAL
static int ssl_pick_cert(mbedtls_ssl_context *ssl,
const mbedtls_ssl_ciphersuite_t *ciphersuite_info)
{
mbedtls_ssl_key_cert *cur, *list;
#if defined(MBEDTLS_USE_PSA_CRYPTO)
psa_algorithm_t pk_alg =
mbedtls_ssl_get_ciphersuite_sig_pk_psa_alg(ciphersuite_info);
psa_key_usage_t pk_usage =
mbedtls_ssl_get_ciphersuite_sig_pk_psa_usage(ciphersuite_info);
#else
mbedtls_pk_type_t pk_alg =
mbedtls_ssl_get_ciphersuite_sig_pk_alg(ciphersuite_info);
#endif /* MBEDTLS_USE_PSA_CRYPTO */
uint32_t flags;
#if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
if (ssl->handshake->sni_key_cert != NULL) {
list = ssl->handshake->sni_key_cert;
} else
#endif
list = ssl->conf->key_cert;
int pk_alg_is_none = 0;
#if defined(MBEDTLS_USE_PSA_CRYPTO)
pk_alg_is_none = (pk_alg == PSA_ALG_NONE);
#else
pk_alg_is_none = (pk_alg == MBEDTLS_PK_NONE);
#endif /* MBEDTLS_USE_PSA_CRYPTO */
if (pk_alg_is_none) {
return 0;
}
MBEDTLS_SSL_DEBUG_MSG(3, ("ciphersuite requires certificate"));
if (list == NULL) {
MBEDTLS_SSL_DEBUG_MSG(3, ("server has no certificate"));
return -1;
}
for (cur = list; cur != NULL; cur = cur->next) {
flags = 0;
MBEDTLS_SSL_DEBUG_CRT(3, "candidate certificate chain, certificate",
cur->cert);
int key_type_matches = 0;
#if defined(MBEDTLS_USE_PSA_CRYPTO)
#if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
key_type_matches = ((ssl->conf->f_async_sign_start != NULL ||
ssl->conf->f_async_decrypt_start != NULL ||
mbedtls_pk_can_do_ext(cur->key, pk_alg, pk_usage)) &&
mbedtls_pk_can_do_ext(&cur->cert->pk, pk_alg, pk_usage));
#else
key_type_matches = (
mbedtls_pk_can_do_ext(cur->key, pk_alg, pk_usage));
#endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
#else
key_type_matches = mbedtls_pk_can_do(&cur->cert->pk, pk_alg);
#endif /* MBEDTLS_USE_PSA_CRYPTO */
if (!key_type_matches) {
MBEDTLS_SSL_DEBUG_MSG(3, ("certificate mismatch: key type"));
continue;
}
/*
* This avoids sending the client a cert it'll reject based on
* keyUsage or other extensions.
*
* It also allows the user to provision different certificates for
* different uses based on keyUsage, eg if they want to avoid signing
* and decrypting with the same RSA key.
*/
if (mbedtls_ssl_check_cert_usage(cur->cert, ciphersuite_info,
MBEDTLS_SSL_IS_SERVER, &flags) != 0) {
MBEDTLS_SSL_DEBUG_MSG(3, ("certificate mismatch: "
"(extended) key usage extension"));
continue;
}
#if defined(MBEDTLS_PK_CAN_ECDSA_SOME)
if (pk_alg == MBEDTLS_PK_ECDSA &&
ssl_check_key_curve(&cur->cert->pk,
ssl->handshake->curves_tls_id) != 0) {
MBEDTLS_SSL_DEBUG_MSG(3, ("certificate mismatch: elliptic curve"));
continue;
}
#endif
/* If we get there, we got a winner */
break;
}
/* Do not update ssl->handshake->key_cert unless there is a match */
if (cur != NULL) {
ssl->handshake->key_cert = cur;
MBEDTLS_SSL_DEBUG_CRT(3, "selected certificate chain, certificate",
ssl->handshake->key_cert->cert);
return 0;
}
return -1;
}
#endif /* MBEDTLS_X509_CRT_PARSE_C */
/*
* Check if a given ciphersuite is suitable for use with our config/keys/etc
* Sets ciphersuite_info only if the suite matches.
*/
MBEDTLS_CHECK_RETURN_CRITICAL
static int ssl_ciphersuite_match(mbedtls_ssl_context *ssl, int suite_id,
const mbedtls_ssl_ciphersuite_t **ciphersuite_info)
{
const mbedtls_ssl_ciphersuite_t *suite_info;
#if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
mbedtls_pk_type_t sig_type;
#endif
suite_info = mbedtls_ssl_ciphersuite_from_id(suite_id);
if (suite_info == NULL) {
MBEDTLS_SSL_DEBUG_MSG(1, ("should never happen"));
return MBEDTLS_ERR_SSL_INTERNAL_ERROR;
}
MBEDTLS_SSL_DEBUG_MSG(3, ("trying ciphersuite: %#04x (%s)",
(unsigned int) suite_id, suite_info->name));
if (suite_info->min_tls_version > ssl->tls_version ||
suite_info->max_tls_version < ssl->tls_version) {
MBEDTLS_SSL_DEBUG_MSG(3, ("ciphersuite mismatch: version"));
return 0;
}
#if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
if (suite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE &&
(ssl->handshake->cli_exts & MBEDTLS_TLS_EXT_ECJPAKE_KKPP_OK) == 0) {
MBEDTLS_SSL_DEBUG_MSG(3, ("ciphersuite mismatch: ecjpake "
"not configured or ext missing"));
return 0;
}
#endif
#if defined(MBEDTLS_PK_CAN_ECDH) || defined(MBEDTLS_PK_CAN_ECDSA_SOME)
if (mbedtls_ssl_ciphersuite_uses_ec(suite_info) &&
(ssl->handshake->curves_tls_id == NULL ||
ssl->handshake->curves_tls_id[0] == 0)) {
MBEDTLS_SSL_DEBUG_MSG(3, ("ciphersuite mismatch: "
"no common elliptic curve"));
return 0;
}
#endif
#if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED)
/* If the ciphersuite requires a pre-shared key and we don't
* have one, skip it now rather than failing later */
if (mbedtls_ssl_ciphersuite_uses_psk(suite_info) &&
ssl_conf_has_psk_or_cb(ssl->conf) == 0) {
MBEDTLS_SSL_DEBUG_MSG(3, ("ciphersuite mismatch: no pre-shared key"));
return 0;
}
#endif
#if defined(MBEDTLS_X509_CRT_PARSE_C)
/*
* Final check: if ciphersuite requires us to have a
* certificate/key of a particular type:
* - select the appropriate certificate if we have one, or
* - try the next ciphersuite if we don't
* This must be done last since we modify the key_cert list.
*/
if (ssl_pick_cert(ssl, suite_info) != 0) {
MBEDTLS_SSL_DEBUG_MSG(3, ("ciphersuite mismatch: "
"no suitable certificate"));
return 0;
}
#endif
#if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
/* If the ciphersuite requires signing, check whether
* a suitable hash algorithm is present. */
sig_type = mbedtls_ssl_get_ciphersuite_sig_alg(suite_info);
if (sig_type != MBEDTLS_PK_NONE &&
mbedtls_ssl_tls12_get_preferred_hash_for_sig_alg(
ssl, mbedtls_ssl_sig_from_pk_alg(sig_type)) == MBEDTLS_SSL_HASH_NONE) {
MBEDTLS_SSL_DEBUG_MSG(3, ("ciphersuite mismatch: no suitable hash algorithm "
"for signature algorithm %u", (unsigned) sig_type));
return 0;
}
#endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
*ciphersuite_info = suite_info;
return 0;
}
/* This function doesn't alert on errors that happen early during
ClientHello parsing because they might indicate that the client is
not talking SSL/TLS at all and would not understand our alert. */
MBEDTLS_CHECK_RETURN_CRITICAL
static int ssl_parse_client_hello(mbedtls_ssl_context *ssl)
{
int ret, got_common_suite;
size_t i, j;
size_t ciph_offset, comp_offset, ext_offset;
size_t msg_len, ciph_len, sess_len, comp_len, ext_len;
#if defined(MBEDTLS_SSL_PROTO_DTLS)
size_t cookie_offset, cookie_len;
#endif
unsigned char *buf, *p, *ext;
#if defined(MBEDTLS_SSL_RENEGOTIATION)
int renegotiation_info_seen = 0;
#endif
int handshake_failure = 0;
const int *ciphersuites;
const mbedtls_ssl_ciphersuite_t *ciphersuite_info;
/* If there is no signature-algorithm extension present,
* we need to fall back to the default values for allowed
* signature-hash pairs. */
#if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
int sig_hash_alg_ext_present = 0;
#endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
MBEDTLS_SSL_DEBUG_MSG(2, ("=> parse client hello"));
int renegotiating;
#if defined(MBEDTLS_SSL_DTLS_ANTI_REPLAY)
read_record_header:
#endif
/*
* If renegotiating, then the input was read with mbedtls_ssl_read_record(),
* otherwise read it ourselves manually in order to support SSLv2
* ClientHello, which doesn't use the same record layer format.
* Otherwise in a scenario of TLS 1.3/TLS 1.2 version negotiation, the
* ClientHello has been already fully fetched by the TLS 1.3 code and the
* flag ssl->keep_current_message is raised.
*/
renegotiating = 0;
#if defined(MBEDTLS_SSL_RENEGOTIATION)
renegotiating = (ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE);
#endif
if (!renegotiating && !ssl->keep_current_message) {
if ((ret = mbedtls_ssl_fetch_input(ssl, 5)) != 0) {
/* No alert on a read error. */
MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_fetch_input", ret);
return ret;
}
}
buf = ssl->in_hdr;
MBEDTLS_SSL_DEBUG_BUF(4, "record header", buf, mbedtls_ssl_in_hdr_len(ssl));
/*
* TLS Client Hello
*
* Record layer:
* 0 . 0 message type
* 1 . 2 protocol version
* 3 . 11 DTLS: epoch + record sequence number
* 3 . 4 message length
*/
MBEDTLS_SSL_DEBUG_MSG(3, ("client hello, message type: %d",
buf[0]));
if (buf[0] != MBEDTLS_SSL_MSG_HANDSHAKE) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message"));
return MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE;
}
MBEDTLS_SSL_DEBUG_MSG(3, ("client hello, message len.: %d",
(ssl->in_len[0] << 8) | ssl->in_len[1]));
MBEDTLS_SSL_DEBUG_MSG(3, ("client hello, protocol version: [%d:%d]",
buf[1], buf[2]));
/* For DTLS if this is the initial handshake, remember the client sequence
* number to use it in our next message (RFC 6347 4.2.1) */
#if defined(MBEDTLS_SSL_PROTO_DTLS)
if (ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM
#if defined(MBEDTLS_SSL_RENEGOTIATION)
&& ssl->renego_status == MBEDTLS_SSL_INITIAL_HANDSHAKE
#endif
) {
/* Epoch should be 0 for initial handshakes */
if (ssl->in_ctr[0] != 0 || ssl->in_ctr[1] != 0) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message"));
return MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER;
}
memcpy(&ssl->cur_out_ctr[2], ssl->in_ctr + 2,
sizeof(ssl->cur_out_ctr) - 2);
#if defined(MBEDTLS_SSL_DTLS_ANTI_REPLAY)
if (mbedtls_ssl_dtls_replay_check(ssl) != 0) {
MBEDTLS_SSL_DEBUG_MSG(1, ("replayed record, discarding"));
ssl->next_record_offset = 0;
ssl->in_left = 0;
goto read_record_header;
}
/* No MAC to check yet, so we can update right now */
mbedtls_ssl_dtls_replay_update(ssl);
#endif
}
#endif /* MBEDTLS_SSL_PROTO_DTLS */
msg_len = (ssl->in_len[0] << 8) | ssl->in_len[1];
#if defined(MBEDTLS_SSL_RENEGOTIATION)
if (ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE) {
/* Set by mbedtls_ssl_read_record() */
msg_len = ssl->in_hslen;
} else
#endif
{
if (ssl->keep_current_message) {
ssl->keep_current_message = 0;
} else {
if (msg_len > MBEDTLS_SSL_IN_CONTENT_LEN) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message"));
return MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER;
}
if ((ret = mbedtls_ssl_fetch_input(ssl,
mbedtls_ssl_in_hdr_len(ssl) + msg_len)) != 0) {
MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_fetch_input", ret);
return ret;
}
/* Done reading this record, get ready for the next one */
#if defined(MBEDTLS_SSL_PROTO_DTLS)
if (ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM) {
ssl->next_record_offset = msg_len + mbedtls_ssl_in_hdr_len(ssl);
} else
#endif
ssl->in_left = 0;
}
}
buf = ssl->in_msg;
MBEDTLS_SSL_DEBUG_BUF(4, "record contents", buf, msg_len);
ret = ssl->handshake->update_checksum(ssl, buf, msg_len);
if (0 != ret) {
MBEDTLS_SSL_DEBUG_RET(1, ("update_checksum"), ret);
return ret;
}
/*
* Handshake layer:
* 0 . 0 handshake type
* 1 . 3 handshake length
* 4 . 5 DTLS only: message sequence number
* 6 . 8 DTLS only: fragment offset
* 9 . 11 DTLS only: fragment length
*/
if (msg_len < mbedtls_ssl_hs_hdr_len(ssl)) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message"));
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
MBEDTLS_SSL_DEBUG_MSG(3, ("client hello v3, handshake type: %d", buf[0]));
if (buf[0] != MBEDTLS_SSL_HS_CLIENT_HELLO) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message"));
return MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE;
}
{
size_t handshake_len = MBEDTLS_GET_UINT24_BE(buf, 1);
MBEDTLS_SSL_DEBUG_MSG(3, ("client hello v3, handshake len.: %u",
(unsigned) handshake_len));
/* The record layer has a record size limit of 2^14 - 1 and
* fragmentation is not supported, so buf[1] should be zero. */
if (buf[1] != 0) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message: %u != 0",
(unsigned) buf[1]));
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
/* We don't support fragmentation of ClientHello (yet?) */
if (msg_len != mbedtls_ssl_hs_hdr_len(ssl) + handshake_len) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message: %u != %u + %u",
(unsigned) msg_len,
(unsigned) mbedtls_ssl_hs_hdr_len(ssl),
(unsigned) handshake_len));
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
}
#if defined(MBEDTLS_SSL_PROTO_DTLS)
if (ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM) {
/*
* Copy the client's handshake message_seq on initial handshakes,
* check sequence number on renego.
*/
#if defined(MBEDTLS_SSL_RENEGOTIATION)
if (ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS) {
/* This couldn't be done in ssl_prepare_handshake_record() */
unsigned int cli_msg_seq = (unsigned int) MBEDTLS_GET_UINT16_BE(ssl->in_msg, 4);
if (cli_msg_seq != ssl->handshake->in_msg_seq) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message_seq: "
"%u (expected %u)", cli_msg_seq,
ssl->handshake->in_msg_seq));
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
ssl->handshake->in_msg_seq++;
} else
#endif
{
unsigned int cli_msg_seq = (unsigned int) MBEDTLS_GET_UINT16_BE(ssl->in_msg, 4);
ssl->handshake->out_msg_seq = cli_msg_seq;
ssl->handshake->in_msg_seq = cli_msg_seq + 1;
}
{
/*
* For now we don't support fragmentation, so make sure
* fragment_offset == 0 and fragment_length == length
*/
size_t fragment_offset, fragment_length, length;
fragment_offset = MBEDTLS_GET_UINT24_BE(ssl->in_msg, 6);
fragment_length = MBEDTLS_GET_UINT24_BE(ssl->in_msg, 9);
length = MBEDTLS_GET_UINT24_BE(ssl->in_msg, 1);
MBEDTLS_SSL_DEBUG_MSG(
4, ("fragment_offset=%u fragment_length=%u length=%u",
(unsigned) fragment_offset, (unsigned) fragment_length,
(unsigned) length));
if (fragment_offset != 0 || length != fragment_length) {
MBEDTLS_SSL_DEBUG_MSG(1, ("ClientHello fragmentation not supported"));
return MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
}
}
}
#endif /* MBEDTLS_SSL_PROTO_DTLS */
buf += mbedtls_ssl_hs_hdr_len(ssl);
msg_len -= mbedtls_ssl_hs_hdr_len(ssl);
/*
* ClientHello layer:
* 0 . 1 protocol version
* 2 . 33 random bytes (starting with 4 bytes of Unix time)
* 34 . 35 session id length (1 byte)
* 35 . 34+x session id
* 35+x . 35+x DTLS only: cookie length (1 byte)
* 36+x . .. DTLS only: cookie
* .. . .. ciphersuite list length (2 bytes)
* .. . .. ciphersuite list
* .. . .. compression alg. list length (1 byte)
* .. . .. compression alg. list
* .. . .. extensions length (2 bytes, optional)
* .. . .. extensions (optional)
*/
/*
* Minimal length (with everything empty and extensions omitted) is
* 2 + 32 + 1 + 2 + 1 = 38 bytes. Check that first, so that we can
* read at least up to session id length without worrying.
*/
if (msg_len < 38) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message"));
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
/*
* Check and save the protocol version
*/
MBEDTLS_SSL_DEBUG_BUF(3, "client hello, version", buf, 2);
ssl->tls_version = mbedtls_ssl_read_version(buf, ssl->conf->transport);
ssl->session_negotiate->tls_version = ssl->tls_version;
if (ssl->tls_version != MBEDTLS_SSL_VERSION_TLS1_2) {
MBEDTLS_SSL_DEBUG_MSG(1, ("server only supports TLS 1.2"));
mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_PROTOCOL_VERSION);
return MBEDTLS_ERR_SSL_BAD_PROTOCOL_VERSION;
}
/*
* Save client random (inc. Unix time)
*/
MBEDTLS_SSL_DEBUG_BUF(3, "client hello, random bytes", buf + 2, 32);
memcpy(ssl->handshake->randbytes, buf + 2, 32);
/*
* Check the session ID length and save session ID
*/
sess_len = buf[34];
if (sess_len > sizeof(ssl->session_negotiate->id) ||
sess_len + 34 + 2 > msg_len) { /* 2 for cipherlist length field */
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message"));
mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR);
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
MBEDTLS_SSL_DEBUG_BUF(3, "client hello, session id", buf + 35, sess_len);
ssl->session_negotiate->id_len = sess_len;
memset(ssl->session_negotiate->id, 0,
sizeof(ssl->session_negotiate->id));
memcpy(ssl->session_negotiate->id, buf + 35,
ssl->session_negotiate->id_len);
/*
* Check the cookie length and content
*/
#if defined(MBEDTLS_SSL_PROTO_DTLS)
if (ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM) {
cookie_offset = 35 + sess_len;
cookie_len = buf[cookie_offset];
if (cookie_offset + 1 + cookie_len + 2 > msg_len) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message"));
mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR);
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
MBEDTLS_SSL_DEBUG_BUF(3, "client hello, cookie",
buf + cookie_offset + 1, cookie_len);
#if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY)
if (ssl->conf->f_cookie_check != NULL
#if defined(MBEDTLS_SSL_RENEGOTIATION)
&& ssl->renego_status == MBEDTLS_SSL_INITIAL_HANDSHAKE
#endif
) {
if (ssl->conf->f_cookie_check(ssl->conf->p_cookie,
buf + cookie_offset + 1, cookie_len,
ssl->cli_id, ssl->cli_id_len) != 0) {
MBEDTLS_SSL_DEBUG_MSG(2, ("cookie verification failed"));
ssl->handshake->cookie_verify_result = 1;
} else {
MBEDTLS_SSL_DEBUG_MSG(2, ("cookie verification passed"));
ssl->handshake->cookie_verify_result = 0;
}
} else
#endif /* MBEDTLS_SSL_DTLS_HELLO_VERIFY */
{
/* We know we didn't send a cookie, so it should be empty */
if (cookie_len != 0) {
/* This may be an attacker's probe, so don't send an alert */
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message"));
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
MBEDTLS_SSL_DEBUG_MSG(2, ("cookie verification skipped"));
}
/*
* Check the ciphersuitelist length (will be parsed later)
*/
ciph_offset = cookie_offset + 1 + cookie_len;
} else
#endif /* MBEDTLS_SSL_PROTO_DTLS */
ciph_offset = 35 + sess_len;
ciph_len = (buf[ciph_offset + 0] << 8)
| (buf[ciph_offset + 1]);
if (ciph_len < 2 ||
ciph_len + 2 + ciph_offset + 1 > msg_len || /* 1 for comp. alg. len */
(ciph_len % 2) != 0) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message"));
mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR);
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
MBEDTLS_SSL_DEBUG_BUF(3, "client hello, ciphersuitelist",
buf + ciph_offset + 2, ciph_len);
/*
* Check the compression algorithm's length.
* The list contents are ignored because implementing
* MBEDTLS_SSL_COMPRESS_NULL is mandatory and is the only
* option supported by Mbed TLS.
*/
comp_offset = ciph_offset + 2 + ciph_len;
comp_len = buf[comp_offset];
if (comp_len < 1 ||
comp_len > 16 ||
comp_len + comp_offset + 1 > msg_len) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message"));
mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR);
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
MBEDTLS_SSL_DEBUG_BUF(3, "client hello, compression",
buf + comp_offset + 1, comp_len);
/*
* Check the extension length
*/
ext_offset = comp_offset + 1 + comp_len;
if (msg_len > ext_offset) {
if (msg_len < ext_offset + 2) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message"));
mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR);
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
ext_len = (buf[ext_offset + 0] << 8)
| (buf[ext_offset + 1]);
if (msg_len != ext_offset + 2 + ext_len) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message"));
mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR);
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
} else {
ext_len = 0;
}
ext = buf + ext_offset + 2;
MBEDTLS_SSL_DEBUG_BUF(3, "client hello extensions", ext, ext_len);
while (ext_len != 0) {
unsigned int ext_id;
unsigned int ext_size;
if (ext_len < 4) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message"));
mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR);
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
ext_id = ((ext[0] << 8) | (ext[1]));
ext_size = ((ext[2] << 8) | (ext[3]));
if (ext_size + 4 > ext_len) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client hello message"));
mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR);
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
switch (ext_id) {
#if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
case MBEDTLS_TLS_EXT_SERVERNAME:
MBEDTLS_SSL_DEBUG_MSG(3, ("found ServerName extension"));
ret = mbedtls_ssl_parse_server_name_ext(ssl, ext + 4,
ext + 4 + ext_size);
if (ret != 0) {
return ret;
}
break;
#endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */
case MBEDTLS_TLS_EXT_RENEGOTIATION_INFO:
MBEDTLS_SSL_DEBUG_MSG(3, ("found renegotiation extension"));
#if defined(MBEDTLS_SSL_RENEGOTIATION)
renegotiation_info_seen = 1;
#endif
ret = ssl_parse_renegotiation_info(ssl, ext + 4, ext_size);
if (ret != 0) {
return ret;
}
break;
#if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
case MBEDTLS_TLS_EXT_SIG_ALG:
MBEDTLS_SSL_DEBUG_MSG(3, ("found signature_algorithms extension"));
ret = mbedtls_ssl_parse_sig_alg_ext(ssl, ext + 4, ext + 4 + ext_size);
if (ret != 0) {
return ret;
}
sig_hash_alg_ext_present = 1;
break;
#endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
#if defined(MBEDTLS_PK_CAN_ECDH) || defined(MBEDTLS_PK_CAN_ECDSA_SOME) || \
defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
case MBEDTLS_TLS_EXT_SUPPORTED_GROUPS:
MBEDTLS_SSL_DEBUG_MSG(3, ("found supported elliptic curves extension"));
ret = ssl_parse_supported_groups_ext(ssl, ext + 4, ext_size);
if (ret != 0) {
return ret;
}
break;
case MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS:
MBEDTLS_SSL_DEBUG_MSG(3, ("found supported point formats extension"));
ssl->handshake->cli_exts |= MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS_PRESENT;
ret = ssl_parse_supported_point_formats(ssl, ext + 4, ext_size);
if (ret != 0) {
return ret;
}
break;
#endif /* MBEDTLS_PK_CAN_ECDH || MBEDTLS_PK_CAN_ECDSA_SOME ||
MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
#if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
case MBEDTLS_TLS_EXT_ECJPAKE_KKPP:
MBEDTLS_SSL_DEBUG_MSG(3, ("found ecjpake kkpp extension"));
ret = ssl_parse_ecjpake_kkpp(ssl, ext + 4, ext_size);
if (ret != 0) {
return ret;
}
break;
#endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
#if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
case MBEDTLS_TLS_EXT_MAX_FRAGMENT_LENGTH:
MBEDTLS_SSL_DEBUG_MSG(3, ("found max fragment length extension"));
ret = ssl_parse_max_fragment_length_ext(ssl, ext + 4, ext_size);
if (ret != 0) {
return ret;
}
break;
#endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */
#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
case MBEDTLS_TLS_EXT_CID:
MBEDTLS_SSL_DEBUG_MSG(3, ("found CID extension"));
ret = ssl_parse_cid_ext(ssl, ext + 4, ext_size);
if (ret != 0) {
return ret;
}
break;
#endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */
#if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
case MBEDTLS_TLS_EXT_ENCRYPT_THEN_MAC:
MBEDTLS_SSL_DEBUG_MSG(3, ("found encrypt then mac extension"));
ret = ssl_parse_encrypt_then_mac_ext(ssl, ext + 4, ext_size);
if (ret != 0) {
return ret;
}
break;
#endif /* MBEDTLS_SSL_ENCRYPT_THEN_MAC */
#if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
case MBEDTLS_TLS_EXT_EXTENDED_MASTER_SECRET:
MBEDTLS_SSL_DEBUG_MSG(3, ("found extended master secret extension"));
ret = ssl_parse_extended_ms_ext(ssl, ext + 4, ext_size);
if (ret != 0) {
return ret;
}
break;
#endif /* MBEDTLS_SSL_EXTENDED_MASTER_SECRET */
#if defined(MBEDTLS_SSL_SESSION_TICKETS)
case MBEDTLS_TLS_EXT_SESSION_TICKET:
MBEDTLS_SSL_DEBUG_MSG(3, ("found session ticket extension"));
ret = ssl_parse_session_ticket_ext(ssl, ext + 4, ext_size);
if (ret != 0) {
return ret;
}
break;
#endif /* MBEDTLS_SSL_SESSION_TICKETS */
#if defined(MBEDTLS_SSL_ALPN)
case MBEDTLS_TLS_EXT_ALPN:
MBEDTLS_SSL_DEBUG_MSG(3, ("found alpn extension"));
ret = mbedtls_ssl_parse_alpn_ext(ssl, ext + 4,
ext + 4 + ext_size);
if (ret != 0) {
return ret;
}
break;
#endif /* MBEDTLS_SSL_SESSION_TICKETS */
#if defined(MBEDTLS_SSL_DTLS_SRTP)
case MBEDTLS_TLS_EXT_USE_SRTP:
MBEDTLS_SSL_DEBUG_MSG(3, ("found use_srtp extension"));
ret = ssl_parse_use_srtp_ext(ssl, ext + 4, ext_size);
if (ret != 0) {
return ret;
}
break;
#endif /* MBEDTLS_SSL_DTLS_SRTP */
default:
MBEDTLS_SSL_DEBUG_MSG(3, ("unknown extension found: %u (ignoring)",
ext_id));
}
ext_len -= 4 + ext_size;
ext += 4 + ext_size;
}
#if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
/*
* Try to fall back to default hash SHA1 if the client
* hasn't provided any preferred signature-hash combinations.
*/
if (!sig_hash_alg_ext_present) {
uint16_t *received_sig_algs = ssl->handshake->received_sig_algs;
const uint16_t default_sig_algs[] = {
#if defined(MBEDTLS_PK_CAN_ECDSA_SOME)
MBEDTLS_SSL_TLS12_SIG_AND_HASH_ALG(MBEDTLS_SSL_SIG_ECDSA,
MBEDTLS_SSL_HASH_SHA1),
#endif
#if defined(MBEDTLS_RSA_C)
MBEDTLS_SSL_TLS12_SIG_AND_HASH_ALG(MBEDTLS_SSL_SIG_RSA,
MBEDTLS_SSL_HASH_SHA1),
#endif
MBEDTLS_TLS_SIG_NONE
};
MBEDTLS_STATIC_ASSERT(sizeof(default_sig_algs) / sizeof(default_sig_algs[0])
<= MBEDTLS_RECEIVED_SIG_ALGS_SIZE,
"default_sig_algs is too big");
memcpy(received_sig_algs, default_sig_algs, sizeof(default_sig_algs));
}
#endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
/*
* Check for TLS_EMPTY_RENEGOTIATION_INFO_SCSV
*/
for (i = 0, p = buf + ciph_offset + 2; i < ciph_len; i += 2, p += 2) {
if (p[0] == 0 && p[1] == MBEDTLS_SSL_EMPTY_RENEGOTIATION_INFO) {
MBEDTLS_SSL_DEBUG_MSG(3, ("received TLS_EMPTY_RENEGOTIATION_INFO "));
#if defined(MBEDTLS_SSL_RENEGOTIATION)
if (ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS) {
MBEDTLS_SSL_DEBUG_MSG(1, ("received RENEGOTIATION SCSV "
"during renegotiation"));
mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE);
return MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE;
}
#endif
ssl->secure_renegotiation = MBEDTLS_SSL_SECURE_RENEGOTIATION;
break;
}
}
/*
* Renegotiation security checks
*/
if (ssl->secure_renegotiation != MBEDTLS_SSL_SECURE_RENEGOTIATION &&
ssl->conf->allow_legacy_renegotiation == MBEDTLS_SSL_LEGACY_BREAK_HANDSHAKE) {
MBEDTLS_SSL_DEBUG_MSG(1, ("legacy renegotiation, breaking off handshake"));
handshake_failure = 1;
}
#if defined(MBEDTLS_SSL_RENEGOTIATION)
else if (ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS &&
ssl->secure_renegotiation == MBEDTLS_SSL_SECURE_RENEGOTIATION &&
renegotiation_info_seen == 0) {
MBEDTLS_SSL_DEBUG_MSG(1, ("renegotiation_info extension missing (secure)"));
handshake_failure = 1;
} else if (ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS &&
ssl->secure_renegotiation == MBEDTLS_SSL_LEGACY_RENEGOTIATION &&
ssl->conf->allow_legacy_renegotiation == MBEDTLS_SSL_LEGACY_NO_RENEGOTIATION) {
MBEDTLS_SSL_DEBUG_MSG(1, ("legacy renegotiation not allowed"));
handshake_failure = 1;
} else if (ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS &&
ssl->secure_renegotiation == MBEDTLS_SSL_LEGACY_RENEGOTIATION &&
renegotiation_info_seen == 1) {
MBEDTLS_SSL_DEBUG_MSG(1, ("renegotiation_info extension present (legacy)"));
handshake_failure = 1;
}
#endif /* MBEDTLS_SSL_RENEGOTIATION */
if (handshake_failure == 1) {
mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE);
return MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE;
}
/*
* Server certification selection (after processing TLS extensions)
*/
if (ssl->conf->f_cert_cb && (ret = ssl->conf->f_cert_cb(ssl)) != 0) {
MBEDTLS_SSL_DEBUG_RET(1, "f_cert_cb", ret);
return ret;
}
#if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
ssl->handshake->sni_name = NULL;
ssl->handshake->sni_name_len = 0;
#endif
/*
* Search for a matching ciphersuite
* (At the end because we need information from the EC-based extensions
* and certificate from the SNI callback triggered by the SNI extension
* or certificate from server certificate selection callback.)
*/
got_common_suite = 0;
ciphersuites = ssl->conf->ciphersuite_list;
ciphersuite_info = NULL;
if (ssl->conf->respect_cli_pref == MBEDTLS_SSL_SRV_CIPHERSUITE_ORDER_CLIENT) {
for (j = 0, p = buf + ciph_offset + 2; j < ciph_len; j += 2, p += 2) {
for (i = 0; ciphersuites[i] != 0; i++) {
if (MBEDTLS_GET_UINT16_BE(p, 0) != ciphersuites[i]) {
continue;
}
got_common_suite = 1;
if ((ret = ssl_ciphersuite_match(ssl, ciphersuites[i],
&ciphersuite_info)) != 0) {
return ret;
}
if (ciphersuite_info != NULL) {
goto have_ciphersuite;
}
}
}
} else {
for (i = 0; ciphersuites[i] != 0; i++) {
for (j = 0, p = buf + ciph_offset + 2; j < ciph_len; j += 2, p += 2) {
if (MBEDTLS_GET_UINT16_BE(p, 0) != ciphersuites[i]) {
continue;
}
got_common_suite = 1;
if ((ret = ssl_ciphersuite_match(ssl, ciphersuites[i],
&ciphersuite_info)) != 0) {
return ret;
}
if (ciphersuite_info != NULL) {
goto have_ciphersuite;
}
}
}
}
if (got_common_suite) {
MBEDTLS_SSL_DEBUG_MSG(1, ("got ciphersuites in common, "
"but none of them usable"));
mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE);
return MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE;
} else {
MBEDTLS_SSL_DEBUG_MSG(1, ("got no ciphersuites in common"));
mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE);
return MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE;
}
have_ciphersuite:
MBEDTLS_SSL_DEBUG_MSG(2, ("selected ciphersuite: %s", ciphersuite_info->name));
ssl->session_negotiate->ciphersuite = ciphersuites[i];
ssl->handshake->ciphersuite_info = ciphersuite_info;
ssl->state++;
#if defined(MBEDTLS_SSL_PROTO_DTLS)
if (ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM) {
mbedtls_ssl_recv_flight_completed(ssl);
}
#endif
/* Debugging-only output for testsuite */
#if defined(MBEDTLS_DEBUG_C) && \
defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
mbedtls_pk_type_t sig_alg = mbedtls_ssl_get_ciphersuite_sig_alg(ciphersuite_info);
if (sig_alg != MBEDTLS_PK_NONE) {
unsigned int sig_hash = mbedtls_ssl_tls12_get_preferred_hash_for_sig_alg(
ssl, mbedtls_ssl_sig_from_pk_alg(sig_alg));
MBEDTLS_SSL_DEBUG_MSG(3, ("client hello v3, signature_algorithm ext: %u",
sig_hash));
} else {
MBEDTLS_SSL_DEBUG_MSG(3, ("no hash algorithm for signature algorithm "
"%u - should not happen", (unsigned) sig_alg));
}
#endif
MBEDTLS_SSL_DEBUG_MSG(2, ("<= parse client hello"));
return 0;
}
#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
static void ssl_write_cid_ext(mbedtls_ssl_context *ssl,
unsigned char *buf,
size_t *olen)
{
unsigned char *p = buf;
size_t ext_len;
const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN;
*olen = 0;
/* Skip writing the extension if we don't want to use it or if
* the client hasn't offered it. */
if (ssl->handshake->cid_in_use == MBEDTLS_SSL_CID_DISABLED) {
return;
}
/* ssl->own_cid_len is at most MBEDTLS_SSL_CID_IN_LEN_MAX
* which is at most 255, so the increment cannot overflow. */
if (end < p || (size_t) (end - p) < (unsigned) (ssl->own_cid_len + 5)) {
MBEDTLS_SSL_DEBUG_MSG(1, ("buffer too small"));
return;
}
MBEDTLS_SSL_DEBUG_MSG(3, ("server hello, adding CID extension"));
/*
* struct {
* opaque cid<0..2^8-1>;
* } ConnectionId;
*/
MBEDTLS_PUT_UINT16_BE(MBEDTLS_TLS_EXT_CID, p, 0);
p += 2;
ext_len = (size_t) ssl->own_cid_len + 1;
MBEDTLS_PUT_UINT16_BE(ext_len, p, 0);
p += 2;
*p++ = (uint8_t) ssl->own_cid_len;
memcpy(p, ssl->own_cid, ssl->own_cid_len);
*olen = ssl->own_cid_len + 5;
}
#endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */
#if defined(MBEDTLS_SSL_SOME_SUITES_USE_CBC_ETM)
static void ssl_write_encrypt_then_mac_ext(mbedtls_ssl_context *ssl,
unsigned char *buf,
size_t *olen)
{
unsigned char *p = buf;
const mbedtls_ssl_ciphersuite_t *suite = NULL;
/*
* RFC 7366: "If a server receives an encrypt-then-MAC request extension
* from a client and then selects a stream or Authenticated Encryption
* with Associated Data (AEAD) ciphersuite, it MUST NOT send an
* encrypt-then-MAC response extension back to the client."
*/
suite = mbedtls_ssl_ciphersuite_from_id(
ssl->session_negotiate->ciphersuite);
if (suite == NULL) {
ssl->session_negotiate->encrypt_then_mac = MBEDTLS_SSL_ETM_DISABLED;
} else {
mbedtls_ssl_mode_t ssl_mode =
mbedtls_ssl_get_mode_from_ciphersuite(
ssl->session_negotiate->encrypt_then_mac,
suite);
if (ssl_mode != MBEDTLS_SSL_MODE_CBC_ETM) {
ssl->session_negotiate->encrypt_then_mac = MBEDTLS_SSL_ETM_DISABLED;
}
}
if (ssl->session_negotiate->encrypt_then_mac == MBEDTLS_SSL_ETM_DISABLED) {
*olen = 0;
return;
}
MBEDTLS_SSL_DEBUG_MSG(3, ("server hello, adding encrypt then mac extension"));
MBEDTLS_PUT_UINT16_BE(MBEDTLS_TLS_EXT_ENCRYPT_THEN_MAC, p, 0);
p += 2;
*p++ = 0x00;
*p++ = 0x00;
*olen = 4;
}
#endif /* MBEDTLS_SSL_SOME_SUITES_USE_CBC_ETM */
#if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
static void ssl_write_extended_ms_ext(mbedtls_ssl_context *ssl,
unsigned char *buf,
size_t *olen)
{
unsigned char *p = buf;
if (ssl->handshake->extended_ms == MBEDTLS_SSL_EXTENDED_MS_DISABLED) {
*olen = 0;
return;
}
MBEDTLS_SSL_DEBUG_MSG(3, ("server hello, adding extended master secret "
"extension"));
MBEDTLS_PUT_UINT16_BE(MBEDTLS_TLS_EXT_EXTENDED_MASTER_SECRET, p, 0);
p += 2;
*p++ = 0x00;
*p++ = 0x00;
*olen = 4;
}
#endif /* MBEDTLS_SSL_EXTENDED_MASTER_SECRET */
#if defined(MBEDTLS_SSL_SESSION_TICKETS)
static void ssl_write_session_ticket_ext(mbedtls_ssl_context *ssl,
unsigned char *buf,
size_t *olen)
{
unsigned char *p = buf;
if (ssl->handshake->new_session_ticket == 0) {
*olen = 0;
return;
}
MBEDTLS_SSL_DEBUG_MSG(3, ("server hello, adding session ticket extension"));
MBEDTLS_PUT_UINT16_BE(MBEDTLS_TLS_EXT_SESSION_TICKET, p, 0);
p += 2;
*p++ = 0x00;
*p++ = 0x00;
*olen = 4;
}
#endif /* MBEDTLS_SSL_SESSION_TICKETS */
static void ssl_write_renegotiation_ext(mbedtls_ssl_context *ssl,
unsigned char *buf,
size_t *olen)
{
unsigned char *p = buf;
if (ssl->secure_renegotiation != MBEDTLS_SSL_SECURE_RENEGOTIATION) {
*olen = 0;
return;
}
MBEDTLS_SSL_DEBUG_MSG(3, ("server hello, secure renegotiation extension"));
MBEDTLS_PUT_UINT16_BE(MBEDTLS_TLS_EXT_RENEGOTIATION_INFO, p, 0);
p += 2;
#if defined(MBEDTLS_SSL_RENEGOTIATION)
if (ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE) {
*p++ = 0x00;
*p++ = (ssl->verify_data_len * 2 + 1) & 0xFF;
*p++ = ssl->verify_data_len * 2 & 0xFF;
memcpy(p, ssl->peer_verify_data, ssl->verify_data_len);
p += ssl->verify_data_len;
memcpy(p, ssl->own_verify_data, ssl->verify_data_len);
p += ssl->verify_data_len;
} else
#endif /* MBEDTLS_SSL_RENEGOTIATION */
{
*p++ = 0x00;
*p++ = 0x01;
*p++ = 0x00;
}
*olen = p - buf;
}
#if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
static void ssl_write_max_fragment_length_ext(mbedtls_ssl_context *ssl,
unsigned char *buf,
size_t *olen)
{
unsigned char *p = buf;
if (ssl->session_negotiate->mfl_code == MBEDTLS_SSL_MAX_FRAG_LEN_NONE) {
*olen = 0;
return;
}
MBEDTLS_SSL_DEBUG_MSG(3, ("server hello, max_fragment_length extension"));
MBEDTLS_PUT_UINT16_BE(MBEDTLS_TLS_EXT_MAX_FRAGMENT_LENGTH, p, 0);
p += 2;
*p++ = 0x00;
*p++ = 1;
*p++ = ssl->session_negotiate->mfl_code;
*olen = 5;
}
#endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */
#if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
static void ssl_write_supported_point_formats_ext(mbedtls_ssl_context *ssl,
unsigned char *buf,
size_t *olen)
{
unsigned char *p = buf;
((void) ssl);
if ((ssl->handshake->cli_exts &
MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS_PRESENT) == 0) {
*olen = 0;
return;
}
MBEDTLS_SSL_DEBUG_MSG(3, ("server hello, supported_point_formats extension"));
MBEDTLS_PUT_UINT16_BE(MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS, p, 0);
p += 2;
*p++ = 0x00;
*p++ = 2;
*p++ = 1;
*p++ = MBEDTLS_ECP_PF_UNCOMPRESSED;
*olen = 6;
}
#endif /* MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C || MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
#if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
static void ssl_write_ecjpake_kkpp_ext(mbedtls_ssl_context *ssl,
unsigned char *buf,
size_t *olen)
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
unsigned char *p = buf;
const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN;
size_t kkpp_len;
*olen = 0;
/* Skip costly computation if not needed */
if (ssl->handshake->ciphersuite_info->key_exchange !=
MBEDTLS_KEY_EXCHANGE_ECJPAKE) {
return;
}
MBEDTLS_SSL_DEBUG_MSG(3, ("server hello, ecjpake kkpp extension"));
if (end - p < 4) {
MBEDTLS_SSL_DEBUG_MSG(1, ("buffer too small"));
return;
}
MBEDTLS_PUT_UINT16_BE(MBEDTLS_TLS_EXT_ECJPAKE_KKPP, p, 0);
p += 2;
#if defined(MBEDTLS_USE_PSA_CRYPTO)
ret = mbedtls_psa_ecjpake_write_round(&ssl->handshake->psa_pake_ctx,
p + 2, end - p - 2, &kkpp_len,
MBEDTLS_ECJPAKE_ROUND_ONE);
if (ret != 0) {
psa_destroy_key(ssl->handshake->psa_pake_password);
psa_pake_abort(&ssl->handshake->psa_pake_ctx);
MBEDTLS_SSL_DEBUG_RET(1, "psa_pake_output", ret);
return;
}
#else
ret = mbedtls_ecjpake_write_round_one(&ssl->handshake->ecjpake_ctx,
p + 2, end - p - 2, &kkpp_len,
ssl->conf->f_rng, ssl->conf->p_rng);
if (ret != 0) {
MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ecjpake_write_round_one", ret);
return;
}
#endif /* MBEDTLS_USE_PSA_CRYPTO */
MBEDTLS_PUT_UINT16_BE(kkpp_len, p, 0);
p += 2;
*olen = kkpp_len + 4;
}
#endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
#if defined(MBEDTLS_SSL_DTLS_SRTP) && defined(MBEDTLS_SSL_PROTO_DTLS)
static void ssl_write_use_srtp_ext(mbedtls_ssl_context *ssl,
unsigned char *buf,
size_t *olen)
{
size_t mki_len = 0, ext_len = 0;
uint16_t profile_value = 0;
const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN;
*olen = 0;
if ((ssl->conf->transport != MBEDTLS_SSL_TRANSPORT_DATAGRAM) ||
(ssl->dtls_srtp_info.chosen_dtls_srtp_profile == MBEDTLS_TLS_SRTP_UNSET)) {
return;
}
MBEDTLS_SSL_DEBUG_MSG(3, ("server hello, adding use_srtp extension"));
if (ssl->conf->dtls_srtp_mki_support == MBEDTLS_SSL_DTLS_SRTP_MKI_SUPPORTED) {
mki_len = ssl->dtls_srtp_info.mki_len;
}
/* The extension total size is 9 bytes :
* - 2 bytes for the extension tag
* - 2 bytes for the total size
* - 2 bytes for the protection profile length
* - 2 bytes for the protection profile
* - 1 byte for the mki length
* + the actual mki length
* Check we have enough room in the output buffer */
if ((size_t) (end - buf) < mki_len + 9) {
MBEDTLS_SSL_DEBUG_MSG(1, ("buffer too small"));
return;
}
/* extension */
MBEDTLS_PUT_UINT16_BE(MBEDTLS_TLS_EXT_USE_SRTP, buf, 0);
/*
* total length 5 and mki value: only one profile(2 bytes)
* and length(2 bytes) and srtp_mki )
*/
ext_len = 5 + mki_len;
MBEDTLS_PUT_UINT16_BE(ext_len, buf, 2);
/* protection profile length: 2 */
buf[4] = 0x00;
buf[5] = 0x02;
profile_value = mbedtls_ssl_check_srtp_profile_value(
ssl->dtls_srtp_info.chosen_dtls_srtp_profile);
if (profile_value != MBEDTLS_TLS_SRTP_UNSET) {
MBEDTLS_PUT_UINT16_BE(profile_value, buf, 6);
} else {
MBEDTLS_SSL_DEBUG_MSG(1, ("use_srtp extension invalid profile"));
return;
}
buf[8] = mki_len & 0xFF;
memcpy(&buf[9], ssl->dtls_srtp_info.mki_value, mki_len);
*olen = 9 + mki_len;
}
#endif /* MBEDTLS_SSL_DTLS_SRTP */
#if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY)
MBEDTLS_CHECK_RETURN_CRITICAL
static int ssl_write_hello_verify_request(mbedtls_ssl_context *ssl)
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
unsigned char *p = ssl->out_msg + 4;
unsigned char *cookie_len_byte;
MBEDTLS_SSL_DEBUG_MSG(2, ("=> write hello verify request"));
/*
* struct {
* ProtocolVersion server_version;
* opaque cookie<0..2^8-1>;
* } HelloVerifyRequest;
*/
/* The RFC is not clear on this point, but sending the actual negotiated
* version looks like the most interoperable thing to do. */
mbedtls_ssl_write_version(p, ssl->conf->transport, ssl->tls_version);
MBEDTLS_SSL_DEBUG_BUF(3, "server version", p, 2);
p += 2;
/* If we get here, f_cookie_check is not null */
if (ssl->conf->f_cookie_write == NULL) {
MBEDTLS_SSL_DEBUG_MSG(1, ("inconsistent cookie callbacks"));
return MBEDTLS_ERR_SSL_INTERNAL_ERROR;
}
/* Skip length byte until we know the length */
cookie_len_byte = p++;
if ((ret = ssl->conf->f_cookie_write(ssl->conf->p_cookie,
&p, ssl->out_buf + MBEDTLS_SSL_OUT_BUFFER_LEN,
ssl->cli_id, ssl->cli_id_len)) != 0) {
MBEDTLS_SSL_DEBUG_RET(1, "f_cookie_write", ret);
return ret;
}
*cookie_len_byte = (unsigned char) (p - (cookie_len_byte + 1));
MBEDTLS_SSL_DEBUG_BUF(3, "cookie sent", cookie_len_byte + 1, *cookie_len_byte);
ssl->out_msglen = p - ssl->out_msg;
ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
ssl->out_msg[0] = MBEDTLS_SSL_HS_HELLO_VERIFY_REQUEST;
ssl->state = MBEDTLS_SSL_SERVER_HELLO_VERIFY_REQUEST_SENT;
if ((ret = mbedtls_ssl_write_handshake_msg(ssl)) != 0) {
MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_write_handshake_msg", ret);
return ret;
}
#if defined(MBEDTLS_SSL_PROTO_DTLS)
if (ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
(ret = mbedtls_ssl_flight_transmit(ssl)) != 0) {
MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_flight_transmit", ret);
return ret;
}
#endif /* MBEDTLS_SSL_PROTO_DTLS */
MBEDTLS_SSL_DEBUG_MSG(2, ("<= write hello verify request"));
return 0;
}
#endif /* MBEDTLS_SSL_DTLS_HELLO_VERIFY */
static void ssl_handle_id_based_session_resumption(mbedtls_ssl_context *ssl)
{
int ret;
mbedtls_ssl_session session_tmp;
mbedtls_ssl_session * const session = ssl->session_negotiate;
/* Resume is 0 by default, see ssl_handshake_init().
* It may be already set to 1 by ssl_parse_session_ticket_ext(). */
if (ssl->handshake->resume == 1) {
return;
}
if (session->id_len == 0) {
return;
}
if (ssl->conf->f_get_cache == NULL) {
return;
}
#if defined(MBEDTLS_SSL_RENEGOTIATION)
if (ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE) {
return;
}
#endif
mbedtls_ssl_session_init(&session_tmp);
ret = ssl->conf->f_get_cache(ssl->conf->p_cache,
session->id,
session->id_len,
&session_tmp);
if (ret != 0) {
goto exit;
}
if (session->ciphersuite != session_tmp.ciphersuite) {
/* Mismatch between cached and negotiated session */
goto exit;
}
/* Move semantics */
mbedtls_ssl_session_free(session);
*session = session_tmp;
memset(&session_tmp, 0, sizeof(session_tmp));
MBEDTLS_SSL_DEBUG_MSG(3, ("session successfully restored from cache"));
ssl->handshake->resume = 1;
exit:
mbedtls_ssl_session_free(&session_tmp);
}
MBEDTLS_CHECK_RETURN_CRITICAL
static int ssl_write_server_hello(mbedtls_ssl_context *ssl)
{
#if defined(MBEDTLS_HAVE_TIME)
mbedtls_time_t t;
#endif
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
size_t olen, ext_len = 0, n;
unsigned char *buf, *p;
MBEDTLS_SSL_DEBUG_MSG(2, ("=> write server hello"));
#if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY)
if (ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
ssl->handshake->cookie_verify_result != 0) {
MBEDTLS_SSL_DEBUG_MSG(2, ("client hello was not authenticated"));
MBEDTLS_SSL_DEBUG_MSG(2, ("<= write server hello"));
return ssl_write_hello_verify_request(ssl);
}
#endif /* MBEDTLS_SSL_DTLS_HELLO_VERIFY */
if (ssl->conf->f_rng == NULL) {
MBEDTLS_SSL_DEBUG_MSG(1, ("no RNG provided"));
return MBEDTLS_ERR_SSL_NO_RNG;
}
/*
* 0 . 0 handshake type
* 1 . 3 handshake length
* 4 . 5 protocol version
* 6 . 9 UNIX time()
* 10 . 37 random bytes
*/
buf = ssl->out_msg;
p = buf + 4;
mbedtls_ssl_write_version(p, ssl->conf->transport, ssl->tls_version);
p += 2;
MBEDTLS_SSL_DEBUG_MSG(3, ("server hello, chosen version: [%d:%d]",
buf[4], buf[5]));
#if defined(MBEDTLS_HAVE_TIME)
t = mbedtls_time(NULL);
MBEDTLS_PUT_UINT32_BE(t, p, 0);
p += 4;
MBEDTLS_SSL_DEBUG_MSG(3, ("server hello, current time: %" MBEDTLS_PRINTF_LONGLONG,
(long long) t));
#else
if ((ret = ssl->conf->f_rng(ssl->conf->p_rng, p, 4)) != 0) {
return ret;
}
p += 4;
#endif /* MBEDTLS_HAVE_TIME */
if ((ret = ssl->conf->f_rng(ssl->conf->p_rng, p, 20)) != 0) {
return ret;
}
p += 20;
#if defined(MBEDTLS_SSL_PROTO_TLS1_3)
/*
* RFC 8446
* TLS 1.3 has a downgrade protection mechanism embedded in the server's
* random value. TLS 1.3 servers which negotiate TLS 1.2 or below in
* response to a ClientHello MUST set the last 8 bytes of their Random
* value specially in their ServerHello.
*/
if (mbedtls_ssl_conf_is_tls13_enabled(ssl->conf)) {
static const unsigned char magic_tls12_downgrade_string[] =
{ 'D', 'O', 'W', 'N', 'G', 'R', 'D', 1 };
MBEDTLS_STATIC_ASSERT(
sizeof(magic_tls12_downgrade_string) == 8,
"magic_tls12_downgrade_string does not have the expected size");
memcpy(p, magic_tls12_downgrade_string,
sizeof(magic_tls12_downgrade_string));
} else
#endif
{
if ((ret = ssl->conf->f_rng(ssl->conf->p_rng, p, 8)) != 0) {
return ret;
}
}
p += 8;
memcpy(ssl->handshake->randbytes + 32, buf + 6, 32);
MBEDTLS_SSL_DEBUG_BUF(3, "server hello, random bytes", buf + 6, 32);
ssl_handle_id_based_session_resumption(ssl);
if (ssl->handshake->resume == 0) {
/*
* New session, create a new session id,
* unless we're about to issue a session ticket
*/
ssl->state++;
#if defined(MBEDTLS_HAVE_TIME)
ssl->session_negotiate->start = mbedtls_time(NULL);
#endif
#if defined(MBEDTLS_SSL_SESSION_TICKETS)
if (ssl->handshake->new_session_ticket != 0) {
ssl->session_negotiate->id_len = n = 0;
memset(ssl->session_negotiate->id, 0, 32);
} else
#endif /* MBEDTLS_SSL_SESSION_TICKETS */
{
ssl->session_negotiate->id_len = n = 32;
if ((ret = ssl->conf->f_rng(ssl->conf->p_rng, ssl->session_negotiate->id,
n)) != 0) {
return ret;
}
}
} else {
/*
* Resuming a session
*/
n = ssl->session_negotiate->id_len;
ssl->state = MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC;
if ((ret = mbedtls_ssl_derive_keys(ssl)) != 0) {
MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_derive_keys", ret);
return ret;
}
}
/*
* 38 . 38 session id length
* 39 . 38+n session id
* 39+n . 40+n chosen ciphersuite
* 41+n . 41+n chosen compression alg.
* 42+n . 43+n extensions length
* 44+n . 43+n+m extensions
*/
*p++ = (unsigned char) ssl->session_negotiate->id_len;
memcpy(p, ssl->session_negotiate->id, ssl->session_negotiate->id_len);
p += ssl->session_negotiate->id_len;
MBEDTLS_SSL_DEBUG_MSG(3, ("server hello, session id len.: %" MBEDTLS_PRINTF_SIZET, n));
MBEDTLS_SSL_DEBUG_BUF(3, "server hello, session id", buf + 39, n);
MBEDTLS_SSL_DEBUG_MSG(3, ("%s session has been resumed",
ssl->handshake->resume ? "a" : "no"));
MBEDTLS_PUT_UINT16_BE(ssl->session_negotiate->ciphersuite, p, 0);
p += 2;
*p++ = MBEDTLS_BYTE_0(MBEDTLS_SSL_COMPRESS_NULL);
MBEDTLS_SSL_DEBUG_MSG(3, ("server hello, chosen ciphersuite: %s",
mbedtls_ssl_get_ciphersuite_name(ssl->session_negotiate->ciphersuite)));
MBEDTLS_SSL_DEBUG_MSG(3, ("server hello, compress alg.: 0x%02X",
(unsigned int) MBEDTLS_SSL_COMPRESS_NULL));
/*
* First write extensions, then the total length
*/
ssl_write_renegotiation_ext(ssl, p + 2 + ext_len, &olen);
ext_len += olen;
#if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
ssl_write_max_fragment_length_ext(ssl, p + 2 + ext_len, &olen);
ext_len += olen;
#endif
#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
ssl_write_cid_ext(ssl, p + 2 + ext_len, &olen);
ext_len += olen;
#endif
#if defined(MBEDTLS_SSL_SOME_SUITES_USE_CBC_ETM)
ssl_write_encrypt_then_mac_ext(ssl, p + 2 + ext_len, &olen);
ext_len += olen;
#endif
#if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
ssl_write_extended_ms_ext(ssl, p + 2 + ext_len, &olen);
ext_len += olen;
#endif
#if defined(MBEDTLS_SSL_SESSION_TICKETS)
ssl_write_session_ticket_ext(ssl, p + 2 + ext_len, &olen);
ext_len += olen;
#endif
#if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
const mbedtls_ssl_ciphersuite_t *suite =
mbedtls_ssl_ciphersuite_from_id(ssl->session_negotiate->ciphersuite);
if (suite != NULL && mbedtls_ssl_ciphersuite_uses_ec(suite)) {
ssl_write_supported_point_formats_ext(ssl, p + 2 + ext_len, &olen);
ext_len += olen;
}
#endif
#if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
ssl_write_ecjpake_kkpp_ext(ssl, p + 2 + ext_len, &olen);
ext_len += olen;
#endif
#if defined(MBEDTLS_SSL_ALPN)
unsigned char *end = buf + MBEDTLS_SSL_OUT_CONTENT_LEN - 4;
if ((ret = mbedtls_ssl_write_alpn_ext(ssl, p + 2 + ext_len, end, &olen))
!= 0) {
return ret;
}
ext_len += olen;
#endif
#if defined(MBEDTLS_SSL_DTLS_SRTP)
ssl_write_use_srtp_ext(ssl, p + 2 + ext_len, &olen);
ext_len += olen;
#endif
MBEDTLS_SSL_DEBUG_MSG(3, ("server hello, total extension length: %" MBEDTLS_PRINTF_SIZET,
ext_len));
if (ext_len > 0) {
MBEDTLS_PUT_UINT16_BE(ext_len, p, 0);
p += 2 + ext_len;
}
ssl->out_msglen = p - buf;
ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
ssl->out_msg[0] = MBEDTLS_SSL_HS_SERVER_HELLO;
ret = mbedtls_ssl_write_handshake_msg(ssl);
MBEDTLS_SSL_DEBUG_MSG(2, ("<= write server hello"));
return ret;
}
#if !defined(MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED)
MBEDTLS_CHECK_RETURN_CRITICAL
static int ssl_write_certificate_request(mbedtls_ssl_context *ssl)
{
const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
ssl->handshake->ciphersuite_info;
MBEDTLS_SSL_DEBUG_MSG(2, ("=> write certificate request"));
if (!mbedtls_ssl_ciphersuite_cert_req_allowed(ciphersuite_info)) {
MBEDTLS_SSL_DEBUG_MSG(2, ("<= skip write certificate request"));
ssl->state++;
return 0;
}
MBEDTLS_SSL_DEBUG_MSG(1, ("should never happen"));
return MBEDTLS_ERR_SSL_INTERNAL_ERROR;
}
#else /* !MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED */
MBEDTLS_CHECK_RETURN_CRITICAL
static int ssl_write_certificate_request(mbedtls_ssl_context *ssl)
{
int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
ssl->handshake->ciphersuite_info;
uint16_t dn_size, total_dn_size; /* excluding length bytes */
size_t ct_len, sa_len; /* including length bytes */
unsigned char *buf, *p;
const unsigned char * const end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN;
const mbedtls_x509_crt *crt;
int authmode;
MBEDTLS_SSL_DEBUG_MSG(2, ("=> write certificate request"));
ssl->state++;
#if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
if (ssl->handshake->sni_authmode != MBEDTLS_SSL_VERIFY_UNSET) {
authmode = ssl->handshake->sni_authmode;
} else
#endif
authmode = ssl->conf->authmode;
if (!mbedtls_ssl_ciphersuite_cert_req_allowed(ciphersuite_info) ||
authmode == MBEDTLS_SSL_VERIFY_NONE) {
MBEDTLS_SSL_DEBUG_MSG(2, ("<= skip write certificate request"));
return 0;
}
/*
* 0 . 0 handshake type
* 1 . 3 handshake length
* 4 . 4 cert type count
* 5 .. m-1 cert types
* m .. m+1 sig alg length (TLS 1.2 only)
* m+1 .. n-1 SignatureAndHashAlgorithms (TLS 1.2 only)
* n .. n+1 length of all DNs
* n+2 .. n+3 length of DN 1
* n+4 .. ... Distinguished Name #1
* ... .. ... length of DN 2, etc.
*/
buf = ssl->out_msg;
p = buf + 4;
/*
* Supported certificate types
*
* ClientCertificateType certificate_types<1..2^8-1>;
* enum { (255) } ClientCertificateType;
*/
ct_len = 0;
#if defined(MBEDTLS_RSA_C)
p[1 + ct_len++] = MBEDTLS_SSL_CERT_TYPE_RSA_SIGN;
#endif
#if defined(MBEDTLS_ECDSA_C)
p[1 + ct_len++] = MBEDTLS_SSL_CERT_TYPE_ECDSA_SIGN;
#endif
p[0] = (unsigned char) ct_len++;
p += ct_len;
sa_len = 0;
/*
* Add signature_algorithms for verify (TLS 1.2)
*
* SignatureAndHashAlgorithm supported_signature_algorithms<2..2^16-2>;
*
* struct {
* HashAlgorithm hash;
* SignatureAlgorithm signature;
* } SignatureAndHashAlgorithm;
*
* enum { (255) } HashAlgorithm;
* enum { (255) } SignatureAlgorithm;
*/
const uint16_t *sig_alg = mbedtls_ssl_get_sig_algs(ssl);
if (sig_alg == NULL) {
return MBEDTLS_ERR_SSL_BAD_CONFIG;
}
for (; *sig_alg != MBEDTLS_TLS_SIG_NONE; sig_alg++) {
unsigned char hash = MBEDTLS_BYTE_1(*sig_alg);
if (mbedtls_ssl_set_calc_verify_md(ssl, hash)) {
continue;
}
if (!mbedtls_ssl_sig_alg_is_supported(ssl, *sig_alg)) {
continue;
}
/* Write elements at offsets starting from 1 (offset 0 is for the
* length). Thus the offset of each element is the length of the
* partial list including that element. */
sa_len += 2;
MBEDTLS_PUT_UINT16_BE(*sig_alg, p, sa_len);
}
/* Fill in list length. */
MBEDTLS_PUT_UINT16_BE(sa_len, p, 0);
sa_len += 2;
p += sa_len;
/*
* DistinguishedName certificate_authorities<0..2^16-1>;
* opaque DistinguishedName<1..2^16-1>;
*/
p += 2;
total_dn_size = 0;
if (ssl->conf->cert_req_ca_list == MBEDTLS_SSL_CERT_REQ_CA_LIST_ENABLED) {
/* NOTE: If trusted certificates are provisioned
* via a CA callback (configured through
* `mbedtls_ssl_conf_ca_cb()`, then the
* CertificateRequest is currently left empty. */
#if defined(MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED)
#if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
if (ssl->handshake->dn_hints != NULL) {
crt = ssl->handshake->dn_hints;
} else
#endif
if (ssl->conf->dn_hints != NULL) {
crt = ssl->conf->dn_hints;
} else
#endif
#if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
if (ssl->handshake->sni_ca_chain != NULL) {
crt = ssl->handshake->sni_ca_chain;
} else
#endif
crt = ssl->conf->ca_chain;
while (crt != NULL && crt->version != 0) {
/* It follows from RFC 5280 A.1 that this length
* can be represented in at most 11 bits. */
dn_size = (uint16_t) crt->subject_raw.len;
if (end < p || (size_t) (end - p) < 2 + (size_t) dn_size) {
MBEDTLS_SSL_DEBUG_MSG(1, ("skipping CAs: buffer too short"));
break;
}
MBEDTLS_PUT_UINT16_BE(dn_size, p, 0);
p += 2;
memcpy(p, crt->subject_raw.p, dn_size);
p += dn_size;
MBEDTLS_SSL_DEBUG_BUF(3, "requested DN", p - dn_size, dn_size);
total_dn_size += 2 + dn_size;
crt = crt->next;
}
}
ssl->out_msglen = p - buf;
ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
ssl->out_msg[0] = MBEDTLS_SSL_HS_CERTIFICATE_REQUEST;
MBEDTLS_PUT_UINT16_BE(total_dn_size, ssl->out_msg, 4 + ct_len + sa_len);
ret = mbedtls_ssl_write_handshake_msg(ssl);
MBEDTLS_SSL_DEBUG_MSG(2, ("<= write certificate request"));
return ret;
}
#endif /* MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED */
#if defined(MBEDTLS_USE_PSA_CRYPTO) && \
(defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) || \
defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED))
MBEDTLS_CHECK_RETURN_CRITICAL
static int ssl_get_ecdh_params_from_cert(mbedtls_ssl_context *ssl)
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
mbedtls_pk_context *pk;
mbedtls_pk_type_t pk_type;
psa_key_attributes_t key_attributes = PSA_KEY_ATTRIBUTES_INIT;
#if !defined(MBEDTLS_PK_USE_PSA_EC_DATA)
uint16_t tls_id = 0;
psa_ecc_family_t ecc_family;
size_t key_len;
mbedtls_ecp_group_id grp_id;
unsigned char buf[PSA_KEY_EXPORT_ECC_KEY_PAIR_MAX_SIZE(PSA_VENDOR_ECC_MAX_CURVE_BITS)];
mbedtls_ecp_keypair *key;
#endif /* !MBEDTLS_PK_USE_PSA_EC_DATA */
pk = mbedtls_ssl_own_key(ssl);
if (pk == NULL) {
return MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
}
pk_type = mbedtls_pk_get_type(pk);
switch (pk_type) {
case MBEDTLS_PK_OPAQUE:
#if defined(MBEDTLS_PK_USE_PSA_EC_DATA)
case MBEDTLS_PK_ECKEY:
case MBEDTLS_PK_ECKEY_DH:
case MBEDTLS_PK_ECDSA:
#endif /* MBEDTLS_PK_USE_PSA_EC_DATA */
if (!mbedtls_pk_can_do(pk, MBEDTLS_PK_ECKEY)) {
return MBEDTLS_ERR_SSL_PK_TYPE_MISMATCH;
}
ssl->handshake->ecdh_psa_privkey = pk->priv_id;
/* Key should not be destroyed in the TLS library */
ssl->handshake->ecdh_psa_privkey_is_external = 1;
status = psa_get_key_attributes(ssl->handshake->ecdh_psa_privkey,
&key_attributes);
if (status != PSA_SUCCESS) {
ssl->handshake->ecdh_psa_privkey = MBEDTLS_SVC_KEY_ID_INIT;
return PSA_TO_MBEDTLS_ERR(status);
}
ssl->handshake->ecdh_psa_type = psa_get_key_type(&key_attributes);
ssl->handshake->ecdh_bits = psa_get_key_bits(&key_attributes);
psa_reset_key_attributes(&key_attributes);
ret = 0;
break;
#if !defined(MBEDTLS_PK_USE_PSA_EC_DATA)
case MBEDTLS_PK_ECKEY:
case MBEDTLS_PK_ECKEY_DH:
case MBEDTLS_PK_ECDSA:
key = mbedtls_pk_ec_rw(*pk);
grp_id = mbedtls_pk_get_group_id(pk);
if (grp_id == MBEDTLS_ECP_DP_NONE) {
return MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
}
tls_id = mbedtls_ssl_get_tls_id_from_ecp_group_id(grp_id);
if (tls_id == 0) {
/* This elliptic curve is not supported */
return MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE;
}
/* If the above conversion to TLS ID was fine, then also this one will
be, so there is no need to check the return value here */
mbedtls_ssl_get_psa_curve_info_from_tls_id(tls_id, &ecc_family,
&ssl->handshake->ecdh_bits);
ssl->handshake->ecdh_psa_type = PSA_KEY_TYPE_ECC_KEY_PAIR(ecc_family);
key_attributes = psa_key_attributes_init();
psa_set_key_usage_flags(&key_attributes, PSA_KEY_USAGE_DERIVE);
psa_set_key_algorithm(&key_attributes, PSA_ALG_ECDH);
psa_set_key_type(&key_attributes,
PSA_KEY_TYPE_ECC_KEY_PAIR(ssl->handshake->ecdh_psa_type));
psa_set_key_bits(&key_attributes, ssl->handshake->ecdh_bits);
key_len = PSA_BITS_TO_BYTES(key->grp.pbits);
ret = mbedtls_ecp_write_key(key, buf, key_len);
if (ret != 0) {
mbedtls_platform_zeroize(buf, sizeof(buf));
break;
}
status = psa_import_key(&key_attributes, buf, key_len,
&ssl->handshake->ecdh_psa_privkey);
if (status != PSA_SUCCESS) {
ret = PSA_TO_MBEDTLS_ERR(status);
mbedtls_platform_zeroize(buf, sizeof(buf));
break;
}
mbedtls_platform_zeroize(buf, sizeof(buf));
ret = 0;
break;
#endif /* !MBEDTLS_PK_USE_PSA_EC_DATA */
default:
ret = MBEDTLS_ERR_SSL_PK_TYPE_MISMATCH;
}
return ret;
}
#elif defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) || \
defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED)
MBEDTLS_CHECK_RETURN_CRITICAL
static int ssl_get_ecdh_params_from_cert(mbedtls_ssl_context *ssl)
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
const mbedtls_pk_context *private_key = mbedtls_ssl_own_key(ssl);
if (private_key == NULL) {
MBEDTLS_SSL_DEBUG_MSG(1, ("got no server private key"));
return MBEDTLS_ERR_SSL_PRIVATE_KEY_REQUIRED;
}
if (!mbedtls_pk_can_do(private_key, MBEDTLS_PK_ECKEY)) {
MBEDTLS_SSL_DEBUG_MSG(1, ("server key not ECDH capable"));
return MBEDTLS_ERR_SSL_PK_TYPE_MISMATCH;
}
if ((ret = mbedtls_ecdh_get_params(&ssl->handshake->ecdh_ctx,
mbedtls_pk_ec_ro(*mbedtls_ssl_own_key(ssl)),
MBEDTLS_ECDH_OURS)) != 0) {
MBEDTLS_SSL_DEBUG_RET(1, ("mbedtls_ecdh_get_params"), ret);
return ret;
}
return 0;
}
#endif /* MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) ||
MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED */
#if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED) && \
defined(MBEDTLS_SSL_ASYNC_PRIVATE)
MBEDTLS_CHECK_RETURN_CRITICAL
static int ssl_resume_server_key_exchange(mbedtls_ssl_context *ssl,
size_t *signature_len)
{
/* Append the signature to ssl->out_msg, leaving 2 bytes for the
* signature length which will be added in ssl_write_server_key_exchange
* after the call to ssl_prepare_server_key_exchange.
* ssl_write_server_key_exchange also takes care of incrementing
* ssl->out_msglen. */
unsigned char *sig_start = ssl->out_msg + ssl->out_msglen + 2;
size_t sig_max_len = (ssl->out_buf + MBEDTLS_SSL_OUT_CONTENT_LEN
- sig_start);
int ret = ssl->conf->f_async_resume(ssl,
sig_start, signature_len, sig_max_len);
if (ret != MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS) {
ssl->handshake->async_in_progress = 0;
mbedtls_ssl_set_async_operation_data(ssl, NULL);
}
MBEDTLS_SSL_DEBUG_RET(2, "ssl_resume_server_key_exchange", ret);
return ret;
}
#endif /* defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED) &&
defined(MBEDTLS_SSL_ASYNC_PRIVATE) */
/* Prepare the ServerKeyExchange message, up to and including
* calculating the signature if any, but excluding formatting the
* signature and sending the message. */
MBEDTLS_CHECK_RETURN_CRITICAL
static int ssl_prepare_server_key_exchange(mbedtls_ssl_context *ssl,
size_t *signature_len)
{
const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
ssl->handshake->ciphersuite_info;
#if defined(MBEDTLS_KEY_EXCHANGE_SOME_PFS_ENABLED)
#if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED)
unsigned char *dig_signed = NULL;
#endif /* MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED */
#endif /* MBEDTLS_KEY_EXCHANGE_SOME_PFS_ENABLED */
(void) ciphersuite_info; /* unused in some configurations */
#if !defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED)
(void) signature_len;
#endif /* MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED */
#if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED)
#if defined(MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH)
size_t out_buf_len = ssl->out_buf_len - (ssl->out_msg - ssl->out_buf);
#else
size_t out_buf_len = MBEDTLS_SSL_OUT_BUFFER_LEN - (ssl->out_msg - ssl->out_buf);
#endif
#endif
ssl->out_msglen = 4; /* header (type:1, length:3) to be written later */
/*
*
* Part 1: Provide key exchange parameters for chosen ciphersuite.
*
*/
/*
* - ECJPAKE key exchanges
*/
#if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
if (ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE) {
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
#if defined(MBEDTLS_USE_PSA_CRYPTO)
unsigned char *out_p = ssl->out_msg + ssl->out_msglen;
unsigned char *end_p = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN -
ssl->out_msglen;
size_t output_offset = 0;
size_t output_len = 0;
/*
* The first 3 bytes are:
* [0] MBEDTLS_ECP_TLS_NAMED_CURVE
* [1, 2] elliptic curve's TLS ID
*
* However since we only support secp256r1 for now, we hardcode its
* TLS ID here
*/
uint16_t tls_id = mbedtls_ssl_get_tls_id_from_ecp_group_id(
MBEDTLS_ECP_DP_SECP256R1);
if (tls_id == 0) {
return MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
}
*out_p = MBEDTLS_ECP_TLS_NAMED_CURVE;
MBEDTLS_PUT_UINT16_BE(tls_id, out_p, 1);
output_offset += 3;
ret = mbedtls_psa_ecjpake_write_round(&ssl->handshake->psa_pake_ctx,
out_p + output_offset,
end_p - out_p - output_offset, &output_len,
MBEDTLS_ECJPAKE_ROUND_TWO);
if (ret != 0) {
psa_destroy_key(ssl->handshake->psa_pake_password);
psa_pake_abort(&ssl->handshake->psa_pake_ctx);
MBEDTLS_SSL_DEBUG_RET(1, "psa_pake_output", ret);
return ret;
}
output_offset += output_len;
ssl->out_msglen += output_offset;
#else
size_t len = 0;
ret = mbedtls_ecjpake_write_round_two(
&ssl->handshake->ecjpake_ctx,
ssl->out_msg + ssl->out_msglen,
MBEDTLS_SSL_OUT_CONTENT_LEN - ssl->out_msglen, &len,
ssl->conf->f_rng, ssl->conf->p_rng);
if (ret != 0) {
MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ecjpake_write_round_two", ret);
return ret;
}
ssl->out_msglen += len;
#endif /* MBEDTLS_USE_PSA_CRYPTO */
}
#endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
/*
* For (EC)DHE key exchanges with PSK, parameters are prefixed by support
* identity hint (RFC 4279, Sec. 3). Until someone needs this feature,
* we use empty support identity hints here.
**/
#if defined(MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED) || \
defined(MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED)
if (ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_PSK ||
ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK) {
ssl->out_msg[ssl->out_msglen++] = 0x00;
ssl->out_msg[ssl->out_msglen++] = 0x00;
}
#endif /* MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED ||
MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED */
/*
* - DHE key exchanges
*/
#if defined(MBEDTLS_KEY_EXCHANGE_SOME_DHE_ENABLED)
if (mbedtls_ssl_ciphersuite_uses_dhe(ciphersuite_info)) {
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
size_t len = 0;
if (ssl->conf->dhm_P.p == NULL || ssl->conf->dhm_G.p == NULL) {
MBEDTLS_SSL_DEBUG_MSG(1, ("no DH parameters set"));
return MBEDTLS_ERR_SSL_BAD_INPUT_DATA;
}
/*
* Ephemeral DH parameters:
*
* struct {
* opaque dh_p<1..2^16-1>;
* opaque dh_g<1..2^16-1>;
* opaque dh_Ys<1..2^16-1>;
* } ServerDHParams;
*/
if ((ret = mbedtls_dhm_set_group(&ssl->handshake->dhm_ctx,
&ssl->conf->dhm_P,
&ssl->conf->dhm_G)) != 0) {
MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_dhm_set_group", ret);
return ret;
}
if ((ret = mbedtls_dhm_make_params(
&ssl->handshake->dhm_ctx,
(int) mbedtls_dhm_get_len(&ssl->handshake->dhm_ctx),
ssl->out_msg + ssl->out_msglen, &len,
ssl->conf->f_rng, ssl->conf->p_rng)) != 0) {
MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_dhm_make_params", ret);
return ret;
}
#if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED)
dig_signed = ssl->out_msg + ssl->out_msglen;
#endif
ssl->out_msglen += len;
MBEDTLS_SSL_DEBUG_MPI(3, "DHM: X ", &ssl->handshake->dhm_ctx.X);
MBEDTLS_SSL_DEBUG_MPI(3, "DHM: P ", &ssl->handshake->dhm_ctx.P);
MBEDTLS_SSL_DEBUG_MPI(3, "DHM: G ", &ssl->handshake->dhm_ctx.G);
MBEDTLS_SSL_DEBUG_MPI(3, "DHM: GX", &ssl->handshake->dhm_ctx.GX);
}
#endif /* MBEDTLS_KEY_EXCHANGE_SOME_DHE_ENABLED */
/*
* - ECDHE key exchanges
*/
#if defined(MBEDTLS_KEY_EXCHANGE_SOME_ECDHE_ENABLED)
if (mbedtls_ssl_ciphersuite_uses_ecdhe(ciphersuite_info)) {
/*
* Ephemeral ECDH parameters:
*
* struct {
* ECParameters curve_params;
* ECPoint public;
* } ServerECDHParams;
*/
uint16_t *curr_tls_id = ssl->handshake->curves_tls_id;
const uint16_t *group_list = mbedtls_ssl_get_groups(ssl);
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
size_t len = 0;
/* Match our preference list against the offered curves */
if ((group_list == NULL) || (curr_tls_id == NULL)) {
return MBEDTLS_ERR_SSL_BAD_CONFIG;
}
for (; *group_list != 0; group_list++) {
for (curr_tls_id = ssl->handshake->curves_tls_id;
*curr_tls_id != 0; curr_tls_id++) {
if (*curr_tls_id == *group_list) {
goto curve_matching_done;
}
}
}
curve_matching_done:
if (*curr_tls_id == 0) {
MBEDTLS_SSL_DEBUG_MSG(1, ("no matching curve for ECDHE"));
return MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE;
}
MBEDTLS_SSL_DEBUG_MSG(2, ("ECDHE curve: %s",
mbedtls_ssl_get_curve_name_from_tls_id(*curr_tls_id)));
#if defined(MBEDTLS_USE_PSA_CRYPTO)
psa_status_t status = PSA_ERROR_GENERIC_ERROR;
psa_key_attributes_t key_attributes;
mbedtls_ssl_handshake_params *handshake = ssl->handshake;
uint8_t *p = ssl->out_msg + ssl->out_msglen;
const size_t header_size = 4; // curve_type(1), namedcurve(2),
// data length(1)
const size_t data_length_size = 1;
psa_ecc_family_t ec_psa_family = 0;
size_t ec_bits = 0;
MBEDTLS_SSL_DEBUG_MSG(1, ("Perform PSA-based ECDH computation."));
/* Convert EC's TLS ID to PSA key type. */
if (mbedtls_ssl_get_psa_curve_info_from_tls_id(*curr_tls_id,
&ec_psa_family,
&ec_bits) == PSA_ERROR_NOT_SUPPORTED) {
MBEDTLS_SSL_DEBUG_MSG(1, ("Invalid ecc group parse."));
return MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER;
}
handshake->ecdh_psa_type = PSA_KEY_TYPE_ECC_KEY_PAIR(ec_psa_family);
handshake->ecdh_bits = ec_bits;
key_attributes = psa_key_attributes_init();
psa_set_key_usage_flags(&key_attributes, PSA_KEY_USAGE_DERIVE);
psa_set_key_algorithm(&key_attributes, PSA_ALG_ECDH);
psa_set_key_type(&key_attributes, handshake->ecdh_psa_type);
psa_set_key_bits(&key_attributes, handshake->ecdh_bits);
/*
* ECParameters curve_params
*
* First byte is curve_type, always named_curve
*/
*p++ = MBEDTLS_ECP_TLS_NAMED_CURVE;
/*
* Next two bytes are the namedcurve value
*/
MBEDTLS_PUT_UINT16_BE(*curr_tls_id, p, 0);
p += 2;
/* Generate ECDH private key. */
status = psa_generate_key(&key_attributes,
&handshake->ecdh_psa_privkey);
if (status != PSA_SUCCESS) {
ret = PSA_TO_MBEDTLS_ERR(status);
MBEDTLS_SSL_DEBUG_RET(1, "psa_generate_key", ret);
return ret;
}
/*
* ECPoint public
*
* First byte is data length.
* It will be filled later. p holds now the data length location.
*/
/* Export the public part of the ECDH private key from PSA.
* Make one byte space for the length.
*/
unsigned char *own_pubkey = p + data_length_size;
size_t own_pubkey_max_len = (size_t) (MBEDTLS_SSL_OUT_CONTENT_LEN
- (own_pubkey - ssl->out_msg));
status = psa_export_public_key(handshake->ecdh_psa_privkey,
own_pubkey, own_pubkey_max_len,
&len);
if (status != PSA_SUCCESS) {
ret = PSA_TO_MBEDTLS_ERR(status);
MBEDTLS_SSL_DEBUG_RET(1, "psa_export_public_key", ret);
(void) psa_destroy_key(handshake->ecdh_psa_privkey);
handshake->ecdh_psa_privkey = MBEDTLS_SVC_KEY_ID_INIT;
return ret;
}
/* Store the length of the exported public key. */
*p = (uint8_t) len;
/* Determine full message length. */
len += header_size;
#else
mbedtls_ecp_group_id curr_grp_id =
mbedtls_ssl_get_ecp_group_id_from_tls_id(*curr_tls_id);
if ((ret = mbedtls_ecdh_setup(&ssl->handshake->ecdh_ctx,
curr_grp_id)) != 0) {
MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ecp_group_load", ret);
return ret;
}
if ((ret = mbedtls_ecdh_make_params(
&ssl->handshake->ecdh_ctx, &len,
ssl->out_msg + ssl->out_msglen,
MBEDTLS_SSL_OUT_CONTENT_LEN - ssl->out_msglen,
ssl->conf->f_rng, ssl->conf->p_rng)) != 0) {
MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ecdh_make_params", ret);
return ret;
}
MBEDTLS_SSL_DEBUG_ECDH(3, &ssl->handshake->ecdh_ctx,
MBEDTLS_DEBUG_ECDH_Q);
#endif /* MBEDTLS_USE_PSA_CRYPTO */
#if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED)
dig_signed = ssl->out_msg + ssl->out_msglen;
#endif
ssl->out_msglen += len;
}
#endif /* MBEDTLS_KEY_EXCHANGE_SOME_ECDHE_ENABLED */
/*
*
* Part 2: For key exchanges involving the server signing the
* exchange parameters, compute and add the signature here.
*
*/
#if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED)
if (mbedtls_ssl_ciphersuite_uses_server_signature(ciphersuite_info)) {
if (dig_signed == NULL) {
MBEDTLS_SSL_DEBUG_MSG(1, ("should never happen"));
return MBEDTLS_ERR_SSL_INTERNAL_ERROR;
}
size_t dig_signed_len = ssl->out_msg + ssl->out_msglen - dig_signed;
size_t hashlen = 0;
unsigned char hash[MBEDTLS_MD_MAX_SIZE];
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
/*
* 2.1: Choose hash algorithm:
* For TLS 1.2, obey signature-hash-algorithm extension
* to choose appropriate hash.
*/
mbedtls_pk_type_t sig_alg =
mbedtls_ssl_get_ciphersuite_sig_pk_alg(ciphersuite_info);
unsigned int sig_hash =
mbedtls_ssl_tls12_get_preferred_hash_for_sig_alg(
ssl, mbedtls_ssl_sig_from_pk_alg(sig_alg));
mbedtls_md_type_t md_alg = mbedtls_ssl_md_alg_from_hash(sig_hash);
/* For TLS 1.2, obey signature-hash-algorithm extension
* (RFC 5246, Sec. 7.4.1.4.1). */
if (sig_alg == MBEDTLS_PK_NONE || md_alg == MBEDTLS_MD_NONE) {
MBEDTLS_SSL_DEBUG_MSG(1, ("should never happen"));
/* (... because we choose a cipher suite
* only if there is a matching hash.) */
return MBEDTLS_ERR_SSL_INTERNAL_ERROR;
}
MBEDTLS_SSL_DEBUG_MSG(3, ("pick hash algorithm %u for signing", (unsigned) md_alg));
/*
* 2.2: Compute the hash to be signed
*/
if (md_alg != MBEDTLS_MD_NONE) {
ret = mbedtls_ssl_get_key_exchange_md_tls1_2(ssl, hash, &hashlen,
dig_signed,
dig_signed_len,
md_alg);
if (ret != 0) {
return ret;
}
} else {
MBEDTLS_SSL_DEBUG_MSG(1, ("should never happen"));
return MBEDTLS_ERR_SSL_INTERNAL_ERROR;
}
MBEDTLS_SSL_DEBUG_BUF(3, "parameters hash", hash, hashlen);
/*
* 2.3: Compute and add the signature
*/
/*
* We need to specify signature and hash algorithm explicitly through
* a prefix to the signature.
*
* struct {
* HashAlgorithm hash;
* SignatureAlgorithm signature;
* } SignatureAndHashAlgorithm;
*
* struct {
* SignatureAndHashAlgorithm algorithm;
* opaque signature<0..2^16-1>;
* } DigitallySigned;
*
*/
ssl->out_msg[ssl->out_msglen++] = mbedtls_ssl_hash_from_md_alg(md_alg);
ssl->out_msg[ssl->out_msglen++] = mbedtls_ssl_sig_from_pk_alg(sig_alg);
#if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
if (ssl->conf->f_async_sign_start != NULL) {
ret = ssl->conf->f_async_sign_start(ssl,
mbedtls_ssl_own_cert(ssl),
md_alg, hash, hashlen);
switch (ret) {
case MBEDTLS_ERR_SSL_HW_ACCEL_FALLTHROUGH:
/* act as if f_async_sign was null */
break;
case 0:
ssl->handshake->async_in_progress = 1;
return ssl_resume_server_key_exchange(ssl, signature_len);
case MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS:
ssl->handshake->async_in_progress = 1;
return MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS;
default:
MBEDTLS_SSL_DEBUG_RET(1, "f_async_sign_start", ret);
return ret;
}
}
#endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
if (mbedtls_ssl_own_key(ssl) == NULL) {
MBEDTLS_SSL_DEBUG_MSG(1, ("got no private key"));
return MBEDTLS_ERR_SSL_PRIVATE_KEY_REQUIRED;
}
/* Append the signature to ssl->out_msg, leaving 2 bytes for the
* signature length which will be added in ssl_write_server_key_exchange
* after the call to ssl_prepare_server_key_exchange.
* ssl_write_server_key_exchange also takes care of incrementing
* ssl->out_msglen. */
if ((ret = mbedtls_pk_sign(mbedtls_ssl_own_key(ssl),
md_alg, hash, hashlen,
ssl->out_msg + ssl->out_msglen + 2,
out_buf_len - ssl->out_msglen - 2,
signature_len,
ssl->conf->f_rng,
ssl->conf->p_rng)) != 0) {
MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_pk_sign", ret);
return ret;
}
}
#endif /* MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED */
return 0;
}
/* Prepare the ServerKeyExchange message and send it. For ciphersuites
* that do not include a ServerKeyExchange message, do nothing. Either
* way, if successful, move on to the next step in the SSL state
* machine. */
MBEDTLS_CHECK_RETURN_CRITICAL
static int ssl_write_server_key_exchange(mbedtls_ssl_context *ssl)
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
size_t signature_len = 0;
#if defined(MBEDTLS_KEY_EXCHANGE_SOME_NON_PFS_ENABLED)
const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
ssl->handshake->ciphersuite_info;
#endif /* MBEDTLS_KEY_EXCHANGE_SOME_NON_PFS_ENABLED */
MBEDTLS_SSL_DEBUG_MSG(2, ("=> write server key exchange"));
#if defined(MBEDTLS_KEY_EXCHANGE_SOME_NON_PFS_ENABLED)
/* Extract static ECDH parameters and abort if ServerKeyExchange
* is not needed. */
if (mbedtls_ssl_ciphersuite_no_pfs(ciphersuite_info)) {
/* For suites involving ECDH, extract DH parameters
* from certificate at this point. */
#if defined(MBEDTLS_KEY_EXCHANGE_SOME_ECDH_ENABLED)
if (mbedtls_ssl_ciphersuite_uses_ecdh(ciphersuite_info)) {
ret = ssl_get_ecdh_params_from_cert(ssl);
if (ret != 0) {
MBEDTLS_SSL_DEBUG_RET(1, "ssl_get_ecdh_params_from_cert", ret);
return ret;
}
}
#endif /* MBEDTLS_KEY_EXCHANGE_SOME_ECDH_ENABLED */
/* Key exchanges not involving ephemeral keys don't use
* ServerKeyExchange, so end here. */
MBEDTLS_SSL_DEBUG_MSG(2, ("<= skip write server key exchange"));
ssl->state++;
return 0;
}
#endif /* MBEDTLS_KEY_EXCHANGE_SOME_NON_PFS_ENABLED */
#if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED) && \
defined(MBEDTLS_SSL_ASYNC_PRIVATE)
/* If we have already prepared the message and there is an ongoing
* signature operation, resume signing. */
if (ssl->handshake->async_in_progress != 0) {
MBEDTLS_SSL_DEBUG_MSG(2, ("resuming signature operation"));
ret = ssl_resume_server_key_exchange(ssl, &signature_len);
} else
#endif /* defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED) &&
defined(MBEDTLS_SSL_ASYNC_PRIVATE) */
{
/* ServerKeyExchange is needed. Prepare the message. */
ret = ssl_prepare_server_key_exchange(ssl, &signature_len);
}
if (ret != 0) {
/* If we're starting to write a new message, set ssl->out_msglen
* to 0. But if we're resuming after an asynchronous message,
* out_msglen is the amount of data written so far and mst be
* preserved. */
if (ret == MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS) {
MBEDTLS_SSL_DEBUG_MSG(2, ("<= write server key exchange (pending)"));
} else {
ssl->out_msglen = 0;
}
return ret;
}
/* If there is a signature, write its length.
* ssl_prepare_server_key_exchange already wrote the signature
* itself at its proper place in the output buffer. */
#if defined(MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED)
if (signature_len != 0) {
ssl->out_msg[ssl->out_msglen++] = MBEDTLS_BYTE_1(signature_len);
ssl->out_msg[ssl->out_msglen++] = MBEDTLS_BYTE_0(signature_len);
MBEDTLS_SSL_DEBUG_BUF(3, "my signature",
ssl->out_msg + ssl->out_msglen,
signature_len);
/* Skip over the already-written signature */
ssl->out_msglen += signature_len;
}
#endif /* MBEDTLS_KEY_EXCHANGE_WITH_SERVER_SIGNATURE_ENABLED */
/* Add header and send. */
ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
ssl->out_msg[0] = MBEDTLS_SSL_HS_SERVER_KEY_EXCHANGE;
ssl->state++;
if ((ret = mbedtls_ssl_write_handshake_msg(ssl)) != 0) {
MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_write_handshake_msg", ret);
return ret;
}
MBEDTLS_SSL_DEBUG_MSG(2, ("<= write server key exchange"));
return 0;
}
MBEDTLS_CHECK_RETURN_CRITICAL
static int ssl_write_server_hello_done(mbedtls_ssl_context *ssl)
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
MBEDTLS_SSL_DEBUG_MSG(2, ("=> write server hello done"));
ssl->out_msglen = 4;
ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
ssl->out_msg[0] = MBEDTLS_SSL_HS_SERVER_HELLO_DONE;
ssl->state++;
#if defined(MBEDTLS_SSL_PROTO_DTLS)
if (ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM) {
mbedtls_ssl_send_flight_completed(ssl);
}
#endif
if ((ret = mbedtls_ssl_write_handshake_msg(ssl)) != 0) {
MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_write_handshake_msg", ret);
return ret;
}
#if defined(MBEDTLS_SSL_PROTO_DTLS)
if (ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
(ret = mbedtls_ssl_flight_transmit(ssl)) != 0) {
MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_flight_transmit", ret);
return ret;
}
#endif /* MBEDTLS_SSL_PROTO_DTLS */
MBEDTLS_SSL_DEBUG_MSG(2, ("<= write server hello done"));
return 0;
}
#if defined(MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED) || \
defined(MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED)
MBEDTLS_CHECK_RETURN_CRITICAL
static int ssl_parse_client_dh_public(mbedtls_ssl_context *ssl, unsigned char **p,
const unsigned char *end)
{
int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
size_t n;
/*
* Receive G^Y mod P, premaster = (G^Y)^X mod P
*/
if (*p + 2 > end) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client key exchange message"));
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
n = ((*p)[0] << 8) | (*p)[1];
*p += 2;
if (*p + n > end) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client key exchange message"));
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
if ((ret = mbedtls_dhm_read_public(&ssl->handshake->dhm_ctx, *p, n)) != 0) {
MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_dhm_read_public", ret);
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
*p += n;
MBEDTLS_SSL_DEBUG_MPI(3, "DHM: GY", &ssl->handshake->dhm_ctx.GY);
return ret;
}
#endif /* MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED ||
MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED */
#if defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED) || \
defined(MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED)
#if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
MBEDTLS_CHECK_RETURN_CRITICAL
static int ssl_resume_decrypt_pms(mbedtls_ssl_context *ssl,
unsigned char *peer_pms,
size_t *peer_pmslen,
size_t peer_pmssize)
{
int ret = ssl->conf->f_async_resume(ssl,
peer_pms, peer_pmslen, peer_pmssize);
if (ret != MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS) {
ssl->handshake->async_in_progress = 0;
mbedtls_ssl_set_async_operation_data(ssl, NULL);
}
MBEDTLS_SSL_DEBUG_RET(2, "ssl_decrypt_encrypted_pms", ret);
return ret;
}
#endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
MBEDTLS_CHECK_RETURN_CRITICAL
static int ssl_decrypt_encrypted_pms(mbedtls_ssl_context *ssl,
const unsigned char *p,
const unsigned char *end,
unsigned char *peer_pms,
size_t *peer_pmslen,
size_t peer_pmssize)
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
mbedtls_x509_crt *own_cert = mbedtls_ssl_own_cert(ssl);
if (own_cert == NULL) {
MBEDTLS_SSL_DEBUG_MSG(1, ("got no local certificate"));
return MBEDTLS_ERR_SSL_NO_CLIENT_CERTIFICATE;
}
mbedtls_pk_context *public_key = &own_cert->pk;
mbedtls_pk_context *private_key = mbedtls_ssl_own_key(ssl);
size_t len = mbedtls_pk_get_len(public_key);
#if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
/* If we have already started decoding the message and there is an ongoing
* decryption operation, resume signing. */
if (ssl->handshake->async_in_progress != 0) {
MBEDTLS_SSL_DEBUG_MSG(2, ("resuming decryption operation"));
return ssl_resume_decrypt_pms(ssl,
peer_pms, peer_pmslen, peer_pmssize);
}
#endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
/*
* Prepare to decrypt the premaster using own private RSA key
*/
if (p + 2 > end) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client key exchange message"));
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
if (*p++ != MBEDTLS_BYTE_1(len) ||
*p++ != MBEDTLS_BYTE_0(len)) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client key exchange message"));
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
if (p + len != end) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client key exchange message"));
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
/*
* Decrypt the premaster secret
*/
#if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
if (ssl->conf->f_async_decrypt_start != NULL) {
ret = ssl->conf->f_async_decrypt_start(ssl,
mbedtls_ssl_own_cert(ssl),
p, len);
switch (ret) {
case MBEDTLS_ERR_SSL_HW_ACCEL_FALLTHROUGH:
/* act as if f_async_decrypt_start was null */
break;
case 0:
ssl->handshake->async_in_progress = 1;
return ssl_resume_decrypt_pms(ssl,
peer_pms,
peer_pmslen,
peer_pmssize);
case MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS:
ssl->handshake->async_in_progress = 1;
return MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS;
default:
MBEDTLS_SSL_DEBUG_RET(1, "f_async_decrypt_start", ret);
return ret;
}
}
#endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
if (!mbedtls_pk_can_do(private_key, MBEDTLS_PK_RSA)) {
MBEDTLS_SSL_DEBUG_MSG(1, ("got no RSA private key"));
return MBEDTLS_ERR_SSL_PRIVATE_KEY_REQUIRED;
}
ret = mbedtls_pk_decrypt(private_key, p, len,
peer_pms, peer_pmslen, peer_pmssize,
ssl->conf->f_rng, ssl->conf->p_rng);
return ret;
}
MBEDTLS_CHECK_RETURN_CRITICAL
static int ssl_parse_encrypted_pms(mbedtls_ssl_context *ssl,
const unsigned char *p,
const unsigned char *end,
size_t pms_offset)
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
unsigned char *pms = ssl->handshake->premaster + pms_offset;
unsigned char ver[2];
unsigned char fake_pms[48], peer_pms[48];
unsigned char mask;
size_t i, peer_pmslen;
unsigned int diff;
/* In case of a failure in decryption, the decryption may write less than
* 2 bytes of output, but we always read the first two bytes. It doesn't
* matter in the end because diff will be nonzero in that case due to
* ret being nonzero, and we only care whether diff is 0.
* But do initialize peer_pms and peer_pmslen for robustness anyway. This
* also makes memory analyzers happy (don't access uninitialized memory,
* even if it's an unsigned char). */
peer_pms[0] = peer_pms[1] = ~0;
peer_pmslen = 0;
ret = ssl_decrypt_encrypted_pms(ssl, p, end,
peer_pms,
&peer_pmslen,
sizeof(peer_pms));
#if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
if (ret == MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS) {
return ret;
}
#endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
mbedtls_ssl_write_version(ver, ssl->conf->transport,
ssl->session_negotiate->tls_version);
/* Avoid data-dependent branches while checking for invalid
* padding, to protect against timing-based Bleichenbacher-type
* attacks. */
diff = (unsigned int) ret;
diff |= peer_pmslen ^ 48;
diff |= peer_pms[0] ^ ver[0];
diff |= peer_pms[1] ^ ver[1];
/* mask = diff ? 0xff : 0x00 using bit operations to avoid branches */
mask = mbedtls_ct_uint_mask(diff);
/*
* Protection against Bleichenbacher's attack: invalid PKCS#1 v1.5 padding
* must not cause the connection to end immediately; instead, send a
* bad_record_mac later in the handshake.
* To protect against timing-based variants of the attack, we must
* not have any branch that depends on whether the decryption was
* successful. In particular, always generate the fake premaster secret,
* regardless of whether it will ultimately influence the output or not.
*/
ret = ssl->conf->f_rng(ssl->conf->p_rng, fake_pms, sizeof(fake_pms));
if (ret != 0) {
/* It's ok to abort on an RNG failure, since this does not reveal
* anything about the RSA decryption. */
return ret;
}
#if defined(MBEDTLS_SSL_DEBUG_ALL)
if (diff != 0) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client key exchange message"));
}
#endif
if (sizeof(ssl->handshake->premaster) < pms_offset ||
sizeof(ssl->handshake->premaster) - pms_offset < 48) {
MBEDTLS_SSL_DEBUG_MSG(1, ("should never happen"));
return MBEDTLS_ERR_SSL_INTERNAL_ERROR;
}
ssl->handshake->pmslen = 48;
/* Set pms to either the true or the fake PMS, without
* data-dependent branches. */
for (i = 0; i < ssl->handshake->pmslen; i++) {
pms[i] = (mask & fake_pms[i]) | ((~mask) & peer_pms[i]);
}
return 0;
}
#endif /* MBEDTLS_KEY_EXCHANGE_RSA_ENABLED ||
MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED */
#if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED)
MBEDTLS_CHECK_RETURN_CRITICAL
static int ssl_parse_client_psk_identity(mbedtls_ssl_context *ssl, unsigned char **p,
const unsigned char *end)
{
int ret = 0;
uint16_t n;
if (ssl_conf_has_psk_or_cb(ssl->conf) == 0) {
MBEDTLS_SSL_DEBUG_MSG(1, ("got no pre-shared key"));
return MBEDTLS_ERR_SSL_PRIVATE_KEY_REQUIRED;
}
/*
* Receive client pre-shared key identity name
*/
if (end - *p < 2) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client key exchange message"));
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
n = ((*p)[0] << 8) | (*p)[1];
*p += 2;
if (n == 0 || n > end - *p) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client key exchange message"));
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
if (ssl->conf->f_psk != NULL) {
if (ssl->conf->f_psk(ssl->conf->p_psk, ssl, *p, n) != 0) {
ret = MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY;
}
} else {
/* Identity is not a big secret since clients send it in the clear,
* but treat it carefully anyway, just in case */
if (n != ssl->conf->psk_identity_len ||
mbedtls_ct_memcmp(ssl->conf->psk_identity, *p, n) != 0) {
ret = MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY;
}
}
if (ret == MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY) {
MBEDTLS_SSL_DEBUG_BUF(3, "Unknown PSK identity", *p, n);
mbedtls_ssl_send_alert_message(ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_UNKNOWN_PSK_IDENTITY);
return MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY;
}
*p += n;
return 0;
}
#endif /* MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED */
MBEDTLS_CHECK_RETURN_CRITICAL
static int ssl_parse_client_key_exchange(mbedtls_ssl_context *ssl)
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
const mbedtls_ssl_ciphersuite_t *ciphersuite_info;
unsigned char *p, *end;
ciphersuite_info = ssl->handshake->ciphersuite_info;
MBEDTLS_SSL_DEBUG_MSG(2, ("=> parse client key exchange"));
#if defined(MBEDTLS_SSL_ASYNC_PRIVATE) && \
(defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED) || \
defined(MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED))
if ((ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK ||
ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA) &&
(ssl->handshake->async_in_progress != 0)) {
/* We've already read a record and there is an asynchronous
* operation in progress to decrypt it. So skip reading the
* record. */
MBEDTLS_SSL_DEBUG_MSG(3, ("will resume decryption of previously-read record"));
} else
#endif
if ((ret = mbedtls_ssl_read_record(ssl, 1)) != 0) {
MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_read_record", ret);
return ret;
}
p = ssl->in_msg + mbedtls_ssl_hs_hdr_len(ssl);
end = ssl->in_msg + ssl->in_hslen;
if (ssl->in_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client key exchange message"));
return MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE;
}
if (ssl->in_msg[0] != MBEDTLS_SSL_HS_CLIENT_KEY_EXCHANGE) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client key exchange message"));
return MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE;
}
#if defined(MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED)
if (ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_RSA) {
if ((ret = ssl_parse_client_dh_public(ssl, &p, end)) != 0) {
MBEDTLS_SSL_DEBUG_RET(1, ("ssl_parse_client_dh_public"), ret);
return ret;
}
if (p != end) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client key exchange"));
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
if ((ret = mbedtls_dhm_calc_secret(&ssl->handshake->dhm_ctx,
ssl->handshake->premaster,
MBEDTLS_PREMASTER_SIZE,
&ssl->handshake->pmslen,
ssl->conf->f_rng, ssl->conf->p_rng)) != 0) {
MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_dhm_calc_secret", ret);
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
MBEDTLS_SSL_DEBUG_MPI(3, "DHM: K ", &ssl->handshake->dhm_ctx.K);
} else
#endif /* MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED */
#if defined(MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED) || \
defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED) || \
defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) || \
defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED)
if (ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_RSA ||
ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA ||
ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDH_RSA ||
ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA) {
#if defined(MBEDTLS_USE_PSA_CRYPTO)
size_t data_len = (size_t) (*p++);
size_t buf_len = (size_t) (end - p);
psa_status_t status = PSA_ERROR_GENERIC_ERROR;
mbedtls_ssl_handshake_params *handshake = ssl->handshake;
MBEDTLS_SSL_DEBUG_MSG(1, ("Read the peer's public key."));
/*
* We must have at least two bytes (1 for length, at least 1 for data)
*/
if (buf_len < 2) {
MBEDTLS_SSL_DEBUG_MSG(1, ("Invalid buffer length"));
return MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
}
if (data_len < 1 || data_len > buf_len) {
MBEDTLS_SSL_DEBUG_MSG(1, ("Invalid data length"));
return MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
}
/* Store peer's ECDH public key. */
memcpy(handshake->ecdh_psa_peerkey, p, data_len);
handshake->ecdh_psa_peerkey_len = data_len;
/* Compute ECDH shared secret. */
status = psa_raw_key_agreement(
PSA_ALG_ECDH, handshake->ecdh_psa_privkey,
handshake->ecdh_psa_peerkey, handshake->ecdh_psa_peerkey_len,
handshake->premaster, sizeof(handshake->premaster),
&handshake->pmslen);
if (status != PSA_SUCCESS) {
ret = PSA_TO_MBEDTLS_ERR(status);
MBEDTLS_SSL_DEBUG_RET(1, "psa_raw_key_agreement", ret);
if (handshake->ecdh_psa_privkey_is_external == 0) {
(void) psa_destroy_key(handshake->ecdh_psa_privkey);
}
handshake->ecdh_psa_privkey = MBEDTLS_SVC_KEY_ID_INIT;
return ret;
}
if (handshake->ecdh_psa_privkey_is_external == 0) {
status = psa_destroy_key(handshake->ecdh_psa_privkey);
if (status != PSA_SUCCESS) {
ret = PSA_TO_MBEDTLS_ERR(status);
MBEDTLS_SSL_DEBUG_RET(1, "psa_destroy_key", ret);
return ret;
}
}
handshake->ecdh_psa_privkey = MBEDTLS_SVC_KEY_ID_INIT;
#else
if ((ret = mbedtls_ecdh_read_public(&ssl->handshake->ecdh_ctx,
p, end - p)) != 0) {
MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ecdh_read_public", ret);
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
MBEDTLS_SSL_DEBUG_ECDH(3, &ssl->handshake->ecdh_ctx,
MBEDTLS_DEBUG_ECDH_QP);
if ((ret = mbedtls_ecdh_calc_secret(&ssl->handshake->ecdh_ctx,
&ssl->handshake->pmslen,
ssl->handshake->premaster,
MBEDTLS_MPI_MAX_SIZE,
ssl->conf->f_rng, ssl->conf->p_rng)) != 0) {
MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ecdh_calc_secret", ret);
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
MBEDTLS_SSL_DEBUG_ECDH(3, &ssl->handshake->ecdh_ctx,
MBEDTLS_DEBUG_ECDH_Z);
#endif /* MBEDTLS_USE_PSA_CRYPTO */
} else
#endif /* MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED ||
MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED ||
MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED ||
MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED */
#if defined(MBEDTLS_KEY_EXCHANGE_PSK_ENABLED)
if (ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_PSK) {
if ((ret = ssl_parse_client_psk_identity(ssl, &p, end)) != 0) {
MBEDTLS_SSL_DEBUG_RET(1, ("ssl_parse_client_psk_identity"), ret);
return ret;
}
if (p != end) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client key exchange"));
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
#if !defined(MBEDTLS_USE_PSA_CRYPTO)
if ((ret = mbedtls_ssl_psk_derive_premaster(ssl,
ciphersuite_info->key_exchange)) != 0) {
MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_psk_derive_premaster", ret);
return ret;
}
#endif /* !MBEDTLS_USE_PSA_CRYPTO */
} else
#endif /* MBEDTLS_KEY_EXCHANGE_PSK_ENABLED */
#if defined(MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED)
if (ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK) {
#if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
if (ssl->handshake->async_in_progress != 0) {
/* There is an asynchronous operation in progress to
* decrypt the encrypted premaster secret, so skip
* directly to resuming this operation. */
MBEDTLS_SSL_DEBUG_MSG(3, ("PSK identity already parsed"));
/* Update p to skip the PSK identity. ssl_parse_encrypted_pms
* won't actually use it, but maintain p anyway for robustness. */
p += ssl->conf->psk_identity_len + 2;
} else
#endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
if ((ret = ssl_parse_client_psk_identity(ssl, &p, end)) != 0) {
MBEDTLS_SSL_DEBUG_RET(1, ("ssl_parse_client_psk_identity"), ret);
return ret;
}
if ((ret = ssl_parse_encrypted_pms(ssl, p, end, 2)) != 0) {
MBEDTLS_SSL_DEBUG_RET(1, ("ssl_parse_encrypted_pms"), ret);
return ret;
}
#if !defined(MBEDTLS_USE_PSA_CRYPTO)
if ((ret = mbedtls_ssl_psk_derive_premaster(ssl,
ciphersuite_info->key_exchange)) != 0) {
MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_psk_derive_premaster", ret);
return ret;
}
#endif /* !MBEDTLS_USE_PSA_CRYPTO */
} else
#endif /* MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED */
#if defined(MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED)
if (ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_PSK) {
if ((ret = ssl_parse_client_psk_identity(ssl, &p, end)) != 0) {
MBEDTLS_SSL_DEBUG_RET(1, ("ssl_parse_client_psk_identity"), ret);
return ret;
}
if ((ret = ssl_parse_client_dh_public(ssl, &p, end)) != 0) {
MBEDTLS_SSL_DEBUG_RET(1, ("ssl_parse_client_dh_public"), ret);
return ret;
}
if (p != end) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad client key exchange"));
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
#if defined(MBEDTLS_USE_PSA_CRYPTO)
unsigned char *pms = ssl->handshake->premaster;
unsigned char *pms_end = pms + sizeof(ssl->handshake->premaster);
size_t pms_len;
/* Write length only when we know the actual value */
if ((ret = mbedtls_dhm_calc_secret(&ssl->handshake->dhm_ctx,
pms + 2, pms_end - (pms + 2), &pms_len,
ssl->conf->f_rng, ssl->conf->p_rng)) != 0) {
MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_dhm_calc_secret", ret);
return ret;
}
MBEDTLS_PUT_UINT16_BE(pms_len, pms, 0);
pms += 2 + pms_len;
MBEDTLS_SSL_DEBUG_MPI(3, "DHM: K ", &ssl->handshake->dhm_ctx.K);
#else
if ((ret = mbedtls_ssl_psk_derive_premaster(ssl,
ciphersuite_info->key_exchange)) != 0) {
MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_psk_derive_premaster", ret);
return ret;
}
#endif /* MBEDTLS_USE_PSA_CRYPTO */
} else
#endif /* MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED */
#if defined(MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED)
if (ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK) {
#if defined(MBEDTLS_USE_PSA_CRYPTO)
psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
psa_status_t destruction_status = PSA_ERROR_CORRUPTION_DETECTED;
uint8_t ecpoint_len;
mbedtls_ssl_handshake_params *handshake = ssl->handshake;
if ((ret = ssl_parse_client_psk_identity(ssl, &p, end)) != 0) {
MBEDTLS_SSL_DEBUG_RET(1, ("ssl_parse_client_psk_identity"), ret);
psa_destroy_key(handshake->ecdh_psa_privkey);
handshake->ecdh_psa_privkey = MBEDTLS_SVC_KEY_ID_INIT;
return ret;
}
/* Keep a copy of the peer's public key */
if (p >= end) {
psa_destroy_key(handshake->ecdh_psa_privkey);
handshake->ecdh_psa_privkey = MBEDTLS_SVC_KEY_ID_INIT;
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
ecpoint_len = *(p++);
if ((size_t) (end - p) < ecpoint_len) {
psa_destroy_key(handshake->ecdh_psa_privkey);
handshake->ecdh_psa_privkey = MBEDTLS_SVC_KEY_ID_INIT;
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
if (ecpoint_len > sizeof(handshake->ecdh_psa_peerkey)) {
psa_destroy_key(handshake->ecdh_psa_privkey);
handshake->ecdh_psa_privkey = MBEDTLS_SVC_KEY_ID_INIT;
return MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE;
}
memcpy(handshake->ecdh_psa_peerkey, p, ecpoint_len);
handshake->ecdh_psa_peerkey_len = ecpoint_len;
p += ecpoint_len;
/* As RFC 5489 section 2, the premaster secret is formed as follows:
* - a uint16 containing the length (in octets) of the ECDH computation
* - the octet string produced by the ECDH computation
* - a uint16 containing the length (in octets) of the PSK
* - the PSK itself
*/
unsigned char *psm = ssl->handshake->premaster;
const unsigned char * const psm_end =
psm + sizeof(ssl->handshake->premaster);
/* uint16 to store length (in octets) of the ECDH computation */
const size_t zlen_size = 2;
size_t zlen = 0;
/* Compute ECDH shared secret. */
status = psa_raw_key_agreement(PSA_ALG_ECDH,
handshake->ecdh_psa_privkey,
handshake->ecdh_psa_peerkey,
handshake->ecdh_psa_peerkey_len,
psm + zlen_size,
psm_end - (psm + zlen_size),
&zlen);
destruction_status = psa_destroy_key(handshake->ecdh_psa_privkey);
handshake->ecdh_psa_privkey = MBEDTLS_SVC_KEY_ID_INIT;
if (status != PSA_SUCCESS) {
return PSA_TO_MBEDTLS_ERR(status);
} else if (destruction_status != PSA_SUCCESS) {
return PSA_TO_MBEDTLS_ERR(destruction_status);
}
/* Write the ECDH computation length before the ECDH computation */
MBEDTLS_PUT_UINT16_BE(zlen, psm, 0);
psm += zlen_size + zlen;
#else /* MBEDTLS_USE_PSA_CRYPTO */
if ((ret = ssl_parse_client_psk_identity(ssl, &p, end)) != 0) {
MBEDTLS_SSL_DEBUG_RET(1, ("ssl_parse_client_psk_identity"), ret);
return ret;
}
if ((ret = mbedtls_ecdh_read_public(&ssl->handshake->ecdh_ctx,
p, end - p)) != 0) {
MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ecdh_read_public", ret);
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
MBEDTLS_SSL_DEBUG_ECDH(3, &ssl->handshake->ecdh_ctx,
MBEDTLS_DEBUG_ECDH_QP);
if ((ret = mbedtls_ssl_psk_derive_premaster(ssl,
ciphersuite_info->key_exchange)) != 0) {
MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_psk_derive_premaster", ret);
return ret;
}
#endif /* MBEDTLS_USE_PSA_CRYPTO */
} else
#endif /* MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED */
#if defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED)
if (ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA) {
if ((ret = ssl_parse_encrypted_pms(ssl, p, end, 0)) != 0) {
MBEDTLS_SSL_DEBUG_RET(1, ("ssl_parse_parse_encrypted_pms_secret"), ret);
return ret;
}
} else
#endif /* MBEDTLS_KEY_EXCHANGE_RSA_ENABLED */
#if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
if (ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE) {
#if defined(MBEDTLS_USE_PSA_CRYPTO)
if ((ret = mbedtls_psa_ecjpake_read_round(
&ssl->handshake->psa_pake_ctx, p, end - p,
MBEDTLS_ECJPAKE_ROUND_TWO)) != 0) {
psa_destroy_key(ssl->handshake->psa_pake_password);
psa_pake_abort(&ssl->handshake->psa_pake_ctx);
MBEDTLS_SSL_DEBUG_RET(1, "psa_pake_input round two", ret);
return ret;
}
#else
ret = mbedtls_ecjpake_read_round_two(&ssl->handshake->ecjpake_ctx,
p, end - p);
if (ret != 0) {
MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ecjpake_read_round_two", ret);
return MBEDTLS_ERR_SSL_INTERNAL_ERROR;
}
ret = mbedtls_ecjpake_derive_secret(&ssl->handshake->ecjpake_ctx,
ssl->handshake->premaster, 32, &ssl->handshake->pmslen,
ssl->conf->f_rng, ssl->conf->p_rng);
if (ret != 0) {
MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ecjpake_derive_secret", ret);
return ret;
}
#endif /* MBEDTLS_USE_PSA_CRYPTO */
} else
#endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
{
MBEDTLS_SSL_DEBUG_MSG(1, ("should never happen"));
return MBEDTLS_ERR_SSL_INTERNAL_ERROR;
}
if ((ret = mbedtls_ssl_derive_keys(ssl)) != 0) {
MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_derive_keys", ret);
return ret;
}
ssl->state++;
MBEDTLS_SSL_DEBUG_MSG(2, ("<= parse client key exchange"));
return 0;
}
#if !defined(MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED)
MBEDTLS_CHECK_RETURN_CRITICAL
static int ssl_parse_certificate_verify(mbedtls_ssl_context *ssl)
{
const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
ssl->handshake->ciphersuite_info;
MBEDTLS_SSL_DEBUG_MSG(2, ("=> parse certificate verify"));
if (!mbedtls_ssl_ciphersuite_cert_req_allowed(ciphersuite_info)) {
MBEDTLS_SSL_DEBUG_MSG(2, ("<= skip parse certificate verify"));
ssl->state++;
return 0;
}
MBEDTLS_SSL_DEBUG_MSG(1, ("should never happen"));
return MBEDTLS_ERR_SSL_INTERNAL_ERROR;
}
#else /* !MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED */
MBEDTLS_CHECK_RETURN_CRITICAL
static int ssl_parse_certificate_verify(mbedtls_ssl_context *ssl)
{
int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
size_t i, sig_len;
unsigned char hash[48];
unsigned char *hash_start = hash;
size_t hashlen;
mbedtls_pk_type_t pk_alg;
mbedtls_md_type_t md_alg;
const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
ssl->handshake->ciphersuite_info;
mbedtls_pk_context *peer_pk;
MBEDTLS_SSL_DEBUG_MSG(2, ("=> parse certificate verify"));
if (!mbedtls_ssl_ciphersuite_cert_req_allowed(ciphersuite_info)) {
MBEDTLS_SSL_DEBUG_MSG(2, ("<= skip parse certificate verify"));
ssl->state++;
return 0;
}
#if defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
if (ssl->session_negotiate->peer_cert == NULL) {
MBEDTLS_SSL_DEBUG_MSG(2, ("<= skip parse certificate verify"));
ssl->state++;
return 0;
}
#else /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
if (ssl->session_negotiate->peer_cert_digest == NULL) {
MBEDTLS_SSL_DEBUG_MSG(2, ("<= skip parse certificate verify"));
ssl->state++;
return 0;
}
#endif /* !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
/* Read the message without adding it to the checksum */
ret = mbedtls_ssl_read_record(ssl, 0 /* no checksum update */);
if (0 != ret) {
MBEDTLS_SSL_DEBUG_RET(1, ("mbedtls_ssl_read_record"), ret);
return ret;
}
ssl->state++;
/* Process the message contents */
if (ssl->in_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE ||
ssl->in_msg[0] != MBEDTLS_SSL_HS_CERTIFICATE_VERIFY) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad certificate verify message"));
return MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE;
}
i = mbedtls_ssl_hs_hdr_len(ssl);
#if !defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
peer_pk = &ssl->handshake->peer_pubkey;
#else /* !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
if (ssl->session_negotiate->peer_cert == NULL) {
/* Should never happen */
return MBEDTLS_ERR_SSL_INTERNAL_ERROR;
}
peer_pk = &ssl->session_negotiate->peer_cert->pk;
#endif /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
/*
* struct {
* SignatureAndHashAlgorithm algorithm; -- TLS 1.2 only
* opaque signature<0..2^16-1>;
* } DigitallySigned;
*/
if (i + 2 > ssl->in_hslen) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad certificate verify message"));
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
/*
* Hash
*/
md_alg = mbedtls_ssl_md_alg_from_hash(ssl->in_msg[i]);
if (md_alg == MBEDTLS_MD_NONE || mbedtls_ssl_set_calc_verify_md(ssl, ssl->in_msg[i])) {
MBEDTLS_SSL_DEBUG_MSG(1, ("peer not adhering to requested sig_alg"
" for verify message"));
return MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER;
}
#if !defined(MBEDTLS_MD_SHA1)
if (MBEDTLS_MD_SHA1 == md_alg) {
hash_start += 16;
}
#endif
/* Info from md_alg will be used instead */
hashlen = 0;
i++;
/*
* Signature
*/
if ((pk_alg = mbedtls_ssl_pk_alg_from_sig(ssl->in_msg[i]))
== MBEDTLS_PK_NONE) {
MBEDTLS_SSL_DEBUG_MSG(1, ("peer not adhering to requested sig_alg"
" for verify message"));
return MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER;
}
/*
* Check the certificate's key type matches the signature alg
*/
if (!mbedtls_pk_can_do(peer_pk, pk_alg)) {
MBEDTLS_SSL_DEBUG_MSG(1, ("sig_alg doesn't match cert key"));
return MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER;
}
i++;
if (i + 2 > ssl->in_hslen) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad certificate verify message"));
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
sig_len = (ssl->in_msg[i] << 8) | ssl->in_msg[i+1];
i += 2;
if (i + sig_len != ssl->in_hslen) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad certificate verify message"));
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
/* Calculate hash and verify signature */
{
size_t dummy_hlen;
ret = ssl->handshake->calc_verify(ssl, hash, &dummy_hlen);
if (0 != ret) {
MBEDTLS_SSL_DEBUG_RET(1, ("calc_verify"), ret);
return ret;
}
}
if ((ret = mbedtls_pk_verify(peer_pk,
md_alg, hash_start, hashlen,
ssl->in_msg + i, sig_len)) != 0) {
MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_pk_verify", ret);
return ret;
}
ret = mbedtls_ssl_update_handshake_status(ssl);
if (0 != ret) {
MBEDTLS_SSL_DEBUG_RET(1, ("mbedtls_ssl_update_handshake_status"), ret);
return ret;
}
MBEDTLS_SSL_DEBUG_MSG(2, ("<= parse certificate verify"));
return ret;
}
#endif /* MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED */
#if defined(MBEDTLS_SSL_SESSION_TICKETS)
MBEDTLS_CHECK_RETURN_CRITICAL
static int ssl_write_new_session_ticket(mbedtls_ssl_context *ssl)
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
size_t tlen;
uint32_t lifetime;
MBEDTLS_SSL_DEBUG_MSG(2, ("=> write new session ticket"));
ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
ssl->out_msg[0] = MBEDTLS_SSL_HS_NEW_SESSION_TICKET;
/*
* struct {
* uint32 ticket_lifetime_hint;
* opaque ticket<0..2^16-1>;
* } NewSessionTicket;
*
* 4 . 7 ticket_lifetime_hint (0 = unspecified)
* 8 . 9 ticket_len (n)
* 10 . 9+n ticket content
*/
if ((ret = ssl->conf->f_ticket_write(ssl->conf->p_ticket,
ssl->session_negotiate,
ssl->out_msg + 10,
ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN,
&tlen, &lifetime)) != 0) {
MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_ticket_write", ret);
tlen = 0;
}
MBEDTLS_PUT_UINT32_BE(lifetime, ssl->out_msg, 4);
MBEDTLS_PUT_UINT16_BE(tlen, ssl->out_msg, 8);
ssl->out_msglen = 10 + tlen;
/*
* Morally equivalent to updating ssl->state, but NewSessionTicket and
* ChangeCipherSpec share the same state.
*/
ssl->handshake->new_session_ticket = 0;
if ((ret = mbedtls_ssl_write_handshake_msg(ssl)) != 0) {
MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_write_handshake_msg", ret);
return ret;
}
MBEDTLS_SSL_DEBUG_MSG(2, ("<= write new session ticket"));
return 0;
}
#endif /* MBEDTLS_SSL_SESSION_TICKETS */
/*
* SSL handshake -- server side -- single step
*/
int mbedtls_ssl_handshake_server_step(mbedtls_ssl_context *ssl)
{
int ret = 0;
MBEDTLS_SSL_DEBUG_MSG(2, ("server state: %d", ssl->state));
switch (ssl->state) {
case MBEDTLS_SSL_HELLO_REQUEST:
ssl->state = MBEDTLS_SSL_CLIENT_HELLO;
break;
/*
* <== ClientHello
*/
case MBEDTLS_SSL_CLIENT_HELLO:
ret = ssl_parse_client_hello(ssl);
break;
#if defined(MBEDTLS_SSL_PROTO_DTLS)
case MBEDTLS_SSL_SERVER_HELLO_VERIFY_REQUEST_SENT:
return MBEDTLS_ERR_SSL_HELLO_VERIFY_REQUIRED;
#endif
/*
* ==> ServerHello
* Certificate
* ( ServerKeyExchange )
* ( CertificateRequest )
* ServerHelloDone
*/
case MBEDTLS_SSL_SERVER_HELLO:
ret = ssl_write_server_hello(ssl);
break;
case MBEDTLS_SSL_SERVER_CERTIFICATE:
ret = mbedtls_ssl_write_certificate(ssl);
break;
case MBEDTLS_SSL_SERVER_KEY_EXCHANGE:
ret = ssl_write_server_key_exchange(ssl);
break;
case MBEDTLS_SSL_CERTIFICATE_REQUEST:
ret = ssl_write_certificate_request(ssl);
break;
case MBEDTLS_SSL_SERVER_HELLO_DONE:
ret = ssl_write_server_hello_done(ssl);
break;
/*
* <== ( Certificate/Alert )
* ClientKeyExchange
* ( CertificateVerify )
* ChangeCipherSpec
* Finished
*/
case MBEDTLS_SSL_CLIENT_CERTIFICATE:
ret = mbedtls_ssl_parse_certificate(ssl);
break;
case MBEDTLS_SSL_CLIENT_KEY_EXCHANGE:
ret = ssl_parse_client_key_exchange(ssl);
break;
case MBEDTLS_SSL_CERTIFICATE_VERIFY:
ret = ssl_parse_certificate_verify(ssl);
break;
case MBEDTLS_SSL_CLIENT_CHANGE_CIPHER_SPEC:
ret = mbedtls_ssl_parse_change_cipher_spec(ssl);
break;
case MBEDTLS_SSL_CLIENT_FINISHED:
ret = mbedtls_ssl_parse_finished(ssl);
break;
/*
* ==> ( NewSessionTicket )
* ChangeCipherSpec
* Finished
*/
case MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC:
#if defined(MBEDTLS_SSL_SESSION_TICKETS)
if (ssl->handshake->new_session_ticket != 0) {
ret = ssl_write_new_session_ticket(ssl);
} else
#endif
ret = mbedtls_ssl_write_change_cipher_spec(ssl);
break;
case MBEDTLS_SSL_SERVER_FINISHED:
ret = mbedtls_ssl_write_finished(ssl);
break;
case MBEDTLS_SSL_FLUSH_BUFFERS:
MBEDTLS_SSL_DEBUG_MSG(2, ("handshake: done"));
ssl->state = MBEDTLS_SSL_HANDSHAKE_WRAPUP;
break;
case MBEDTLS_SSL_HANDSHAKE_WRAPUP:
mbedtls_ssl_handshake_wrapup(ssl);
break;
default:
MBEDTLS_SSL_DEBUG_MSG(1, ("invalid state %d", ssl->state));
return MBEDTLS_ERR_SSL_BAD_INPUT_DATA;
}
return ret;
}
void mbedtls_ssl_conf_preference_order(mbedtls_ssl_config *conf, int order)
{
conf->respect_cli_pref = order;
}
#endif /* MBEDTLS_SSL_SRV_C && MBEDTLS_SSL_PROTO_TLS1_2 */
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