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mbedtls/library/ssl_tls12_server.c
Manuel Pégourié-Gonnard ef25a99f20
Merge pull request #6533 from valeriosetti/issue5847 
Use PSA EC-JPAKE in TLS (1.2) - Part 2
2022-11-23 13:27:30 +01:00

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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 "hash_info.h"
#include <string.h>
#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_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
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;
const mbedtls_ecp_curve_info *curve_info, **curves;
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 != 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 = mbedtls_calloc( our_size, sizeof( *curves ) ) ) == 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 = curves;
p = buf + 2;
while( list_size > 0 && our_size > 1 )
{
curve_info = mbedtls_ecp_curve_info_from_tls_id( ( p[0] << 8 ) | p[1] );
if( curve_info != NULL )
{
*curves++ = curve_info;
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) || defined(MBEDTLS_ECDSA_C) )
ssl->handshake->ecdh_ctx.point_format = p[0];
#endif /* !MBEDTLS_USE_PSA_CRYPTO &&
( MBEDTLS_ECDH_C || MBEDTLS_ECDSA_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_ECDH_C || MBEDTLS_ECDSA_C ||
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 );
}
/*
* Quoting draft-ietf-tls-dtls-connection-id-05
* https://tools.ietf.org/html/draft-ietf-tls-dtls-connection-id-05
*
* 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_ECDSA_C)
MBEDTLS_CHECK_RETURN_CRITICAL
static int ssl_check_key_curve( mbedtls_pk_context *pk,
const mbedtls_ecp_curve_info **curves )
{
const mbedtls_ecp_curve_info **crv = curves;
mbedtls_ecp_group_id grp_id = mbedtls_pk_ec( *pk )->grp.id;
while( *crv != NULL )
{
if( (*crv)->grp_id == grp_id )
return( 0 );
crv++;
}
return( -1 );
}
#endif /* MBEDTLS_ECDSA_C */
/*
* 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_ECDSA_C)
if( pk_alg == MBEDTLS_PK_ECDSA &&
ssl_check_key_curve( &cur->cert->pk, ssl->handshake->curves ) != 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_ECDH_C) || defined(MBEDTLS_ECDSA_C)
if( mbedtls_ssl_ciphersuite_uses_ec( suite_info ) &&
( ssl->handshake->curves == NULL ||
ssl->handshake->curves[0] == NULL ) )
{
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.
*/
renegotiating = 0;
#if defined(MBEDTLS_SSL_RENEGOTIATION)
renegotiating = ( ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE );
#endif
if( !renegotiating )
{
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( 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 );
ssl->handshake->update_checksum( ssl, buf, msg_len );
/*
* 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 = ( ssl->in_msg[4] << 8 ) |
ssl->in_msg[5];
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 = ( ssl->in_msg[4] << 8 ) |
ssl->in_msg[5];
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->verify_cookie_len = 1;
}
else
{
MBEDTLS_SSL_DEBUG_MSG( 2, ( "cookie verification passed" ) );
ssl->handshake->verify_cookie_len = 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_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
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_ECDH_C || MBEDTLS_ECDSA_C ||
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_ECDSA_C)
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
};
#if defined(static_assert)
static_assert( sizeof( default_sig_algs ) / sizeof( default_sig_algs[0] ) <=
MBEDTLS_RECEIVED_SIG_ALGS_SIZE, "default_sig_algs is too big" );
#endif
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" ) );
/*
* Quoting draft-ietf-tls-dtls-connection-id-05
* https://tools.ietf.org/html/draft-ietf-tls-dtls-connection-id-05
*
* 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->verify_cookie_len != 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, 28 ) ) != 0 )
return( ret );
p += 28;
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;
unsigned char buf[
PSA_KEY_EXPORT_ECC_KEY_PAIR_MAX_SIZE(PSA_VENDOR_ECC_MAX_CURVE_BITS)];
psa_key_attributes_t key_attributes = PSA_KEY_ATTRIBUTES_INIT;
size_t ecdh_bits = 0;
size_t key_len;
mbedtls_pk_context *pk;
mbedtls_ecp_keypair *key;
pk = mbedtls_ssl_own_key( ssl );
if( pk == NULL )
return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
switch( mbedtls_pk_get_type( pk ) )
{
case MBEDTLS_PK_OPAQUE:
if( ! mbedtls_pk_can_do( pk, MBEDTLS_PK_ECKEY ) )
return( MBEDTLS_ERR_SSL_PK_TYPE_MISMATCH );
ssl->handshake->ecdh_psa_privkey =
*( (mbedtls_svc_key_id_t*) pk->pk_ctx );
/* 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_ssl_status_to_mbedtls( 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;
case MBEDTLS_PK_ECKEY:
case MBEDTLS_PK_ECKEY_DH:
case MBEDTLS_PK_ECDSA:
key = mbedtls_pk_ec( *pk );
if( key == NULL )
return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
/* Convert EC group to PSA key type. */
if( ( ssl->handshake->ecdh_psa_type =
mbedtls_ecc_group_to_psa( key->grp.id,
&ecdh_bits ) ) == 0 )
{
return( MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE );
}
ssl->handshake->ecdh_bits = ecdh_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,
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 )
goto cleanup;
status = psa_import_key( &key_attributes, buf, key_len,
&ssl->handshake->ecdh_psa_privkey );
if( status != PSA_SUCCESS )
{
ret = psa_ssl_status_to_mbedtls( status );
goto cleanup;
}
ret = 0;
break;
default:
ret = MBEDTLS_ERR_SSL_PK_TYPE_MISMATCH;
}
cleanup:
mbedtls_platform_zeroize( buf, sizeof( buf ) );
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( *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;
const mbedtls_ecp_curve_info *curve_info;
/*
* 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
*/
if( ( curve_info = mbedtls_ecp_curve_info_from_grp_id(
MBEDTLS_ECP_DP_SECP256R1 ) ) == NULL )
{
return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
}
*out_p = MBEDTLS_ECP_TLS_NAMED_CURVE;
MBEDTLS_PUT_UINT16_BE( curve_info->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;
*/
const mbedtls_ecp_curve_info **curve = NULL;
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 )
return( MBEDTLS_ERR_SSL_BAD_CONFIG );
for( ; *group_list != 0; group_list++ )
for( curve = ssl->handshake->curves; *curve != NULL; curve++ )
if( (*curve)->tls_id == *group_list )
goto curve_matching_done;
curve_matching_done:
if( curve == NULL || *curve == NULL )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "no matching curve for ECDHE" ) );
return( MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE );
}
MBEDTLS_SSL_DEBUG_MSG( 2, ( "ECDHE curve: %s", (*curve)->name ) );
#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;
size_t ecdh_bits = 0;
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;
MBEDTLS_SSL_DEBUG_MSG( 1, ( "Perform PSA-based ECDH computation." ) );
/* Convert EC group to PSA key type. */
handshake->ecdh_psa_type = mbedtls_psa_parse_tls_ecc_group(
(*curve)->tls_id, &ecdh_bits );
if( handshake->ecdh_psa_type == 0 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "Invalid ecc group parse." ) );
return( MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER );
}
handshake->ecdh_bits = ecdh_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( (*curve)->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_ssl_status_to_mbedtls( 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_ssl_status_to_mbedtls( 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
if( ( ret = mbedtls_ecdh_setup( &ssl->handshake->ecdh_ctx,
(*curve)->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_HASH_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_ssl_status_to_mbedtls( 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_ssl_status_to_mbedtls( 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_ssl_status_to_mbedtls( status ) );
else if( destruction_status != PSA_SUCCESS )
return( psa_ssl_status_to_mbedtls( 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;
ssl->handshake->calc_verify( ssl, hash, &dummy_hlen );
}
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 );
}
mbedtls_ssl_update_handshake_status( ssl );
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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