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mbedtls/library/ssl_srv.c
Paul Bakker 78a8c71993 Re-added support for parsing and handling SSLv2 Client Hello messages 
If the define POLARSSL_SSL_SRV_SUPPORT_SSLV2_CLIENT_HELLO is enabled,
the SSL Server module can handle the old SSLv2 Client Hello messages.

It has been updated to deny SSLv2 Client Hello messages during
renegotiation.
2013-03-06 18:01:03 +01:00

1620 lines
48 KiB
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/*
* SSLv3/TLSv1 server-side functions
*
* Copyright (C) 2006-2012, Brainspark B.V.
*
* This file is part of PolarSSL (http://www.polarssl.org)
* Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>
*
* All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "polarssl/config.h"
#if defined(POLARSSL_SSL_SRV_C)
#include "polarssl/debug.h"
#include "polarssl/ssl.h"
#include <stdlib.h>
#include <stdio.h>
#include <time.h>
static int ssl_parse_servername_ext( ssl_context *ssl,
const unsigned char *buf,
size_t len )
{
int ret;
size_t servername_list_size, hostname_len;
const unsigned char *p;
servername_list_size = ( ( buf[0] << 8 ) | ( buf[1] ) );
if( servername_list_size + 2 != len )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
p = buf + 2;
while( servername_list_size > 0 )
{
hostname_len = ( ( p[1] << 8 ) | p[2] );
if( hostname_len + 3 > servername_list_size )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
if( p[0] == TLS_EXT_SERVERNAME_HOSTNAME )
{
ret = ssl->f_sni( ssl->p_sni, ssl, p + 3, hostname_len );
if( ret != 0 )
{
ssl_send_alert_message( ssl, SSL_ALERT_LEVEL_FATAL,
SSL_ALERT_MSG_UNRECOGNIZED_NAME );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
return( 0 );
}
servername_list_size -= hostname_len + 3;
p += hostname_len + 3;
}
if( servername_list_size != 0 )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
return( 0 );
}
static int ssl_parse_renegotiation_info( ssl_context *ssl,
const unsigned char *buf,
size_t len )
{
int ret;
if( ssl->renegotiation == SSL_INITIAL_HANDSHAKE )
{
if( len != 1 || buf[0] != 0x0 )
{
SSL_DEBUG_MSG( 1, ( "non-zero length renegotiated connection field" ) );
if( ( ret = ssl_send_fatal_handshake_failure( ssl ) ) != 0 )
return( ret );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
ssl->secure_renegotiation = SSL_SECURE_RENEGOTIATION;
}
else
{
if( len != 1 + ssl->verify_data_len ||
buf[0] != ssl->verify_data_len ||
memcmp( buf + 1, ssl->peer_verify_data, ssl->verify_data_len ) != 0 )
{
SSL_DEBUG_MSG( 1, ( "non-matching renegotiated connection field" ) );
if( ( ret = ssl_send_fatal_handshake_failure( ssl ) ) != 0 )
return( ret );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
}
return( 0 );
}
static int ssl_parse_signature_algorithms_ext( ssl_context *ssl,
const unsigned char *buf,
size_t len )
{
size_t sig_alg_list_size;
const unsigned char *p;
sig_alg_list_size = ( ( buf[0] << 8 ) | ( buf[1] ) );
if( sig_alg_list_size + 2 != len ||
sig_alg_list_size %2 != 0 )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
p = buf + 2;
while( sig_alg_list_size > 0 )
{
if( p[1] != SSL_SIG_RSA )
{
sig_alg_list_size -= 2;
p += 2;
continue;
}
#if defined(POLARSSL_SHA4_C)
if( p[0] == SSL_HASH_SHA512 )
{
ssl->handshake->sig_alg = SSL_HASH_SHA512;
break;
}
if( p[0] == SSL_HASH_SHA384 )
{
ssl->handshake->sig_alg = SSL_HASH_SHA384;
break;
}
#endif
#if defined(POLARSSL_SHA2_C)
if( p[0] == SSL_HASH_SHA256 )
{
ssl->handshake->sig_alg = SSL_HASH_SHA256;
break;
}
if( p[0] == SSL_HASH_SHA224 )
{
ssl->handshake->sig_alg = SSL_HASH_SHA224;
break;
}
#endif
if( p[0] == SSL_HASH_SHA1 )
{
ssl->handshake->sig_alg = SSL_HASH_SHA1;
break;
}
if( p[0] == SSL_HASH_MD5 )
{
ssl->handshake->sig_alg = SSL_HASH_MD5;
break;
}
sig_alg_list_size -= 2;
p += 2;
}
SSL_DEBUG_MSG( 3, ( "client hello v3, signature_algorithm ext: %d",
ssl->handshake->sig_alg ) );
return( 0 );
}
#if defined(POLARSSL_SSL_SRV_SUPPORT_SSLV2_CLIENT_HELLO)
static int ssl_parse_client_hello_v2( ssl_context *ssl )
{
int ret;
unsigned int i, j;
size_t n;
unsigned int ciph_len, sess_len, chal_len;
unsigned char *buf, *p;
SSL_DEBUG_MSG( 2, ( "=> parse client hello v2" ) );
if( ssl->renegotiation != SSL_INITIAL_HANDSHAKE )
{
SSL_DEBUG_MSG( 1, ( "client hello v2 illegal for renegotiation" ) );
if( ( ret = ssl_send_fatal_handshake_failure( ssl ) ) != 0 )
return( ret );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
buf = ssl->in_hdr;
SSL_DEBUG_BUF( 4, "record header", buf, 5 );
SSL_DEBUG_MSG( 3, ( "client hello v2, message type: %d",
buf[2] ) );
SSL_DEBUG_MSG( 3, ( "client hello v2, message len.: %d",
( ( buf[0] & 0x7F ) << 8 ) | buf[1] ) );
SSL_DEBUG_MSG( 3, ( "client hello v2, max. version: [%d:%d]",
buf[3], buf[4] ) );
/*
* SSLv2 Client Hello
*
* Record layer:
* 0 . 1 message length
*
* SSL layer:
* 2 . 2 message type
* 3 . 4 protocol version
*/
if( buf[2] != SSL_HS_CLIENT_HELLO ||
buf[3] != SSL_MAJOR_VERSION_3 )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
n = ( ( buf[0] << 8 ) | buf[1] ) & 0x7FFF;
if( n < 17 || n > 512 )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
ssl->major_ver = SSL_MAJOR_VERSION_3;
ssl->minor_ver = ( buf[4] <= SSL_MINOR_VERSION_3 )
? buf[4] : SSL_MINOR_VERSION_3;
if( ssl->minor_ver < ssl->min_minor_ver )
{
SSL_DEBUG_MSG( 1, ( "client only supports ssl smaller than minimum"
" [%d:%d] < [%d:%d]", ssl->major_ver, ssl->minor_ver,
ssl->min_major_ver, ssl->min_minor_ver ) );
ssl_send_alert_message( ssl, SSL_ALERT_LEVEL_FATAL,
SSL_ALERT_MSG_PROTOCOL_VERSION );
return( POLARSSL_ERR_SSL_BAD_HS_PROTOCOL_VERSION );
}
ssl->max_major_ver = buf[3];
ssl->max_minor_ver = buf[4];
if( ( ret = ssl_fetch_input( ssl, 2 + n ) ) != 0 )
{
SSL_DEBUG_RET( 1, "ssl_fetch_input", ret );
return( ret );
}
ssl->handshake->update_checksum( ssl, buf + 2, n );
buf = ssl->in_msg;
n = ssl->in_left - 5;
/*
* 0 . 1 ciphersuitelist length
* 2 . 3 session id length
* 4 . 5 challenge length
* 6 . .. ciphersuitelist
* .. . .. session id
* .. . .. challenge
*/
SSL_DEBUG_BUF( 4, "record contents", buf, n );
ciph_len = ( buf[0] << 8 ) | buf[1];
sess_len = ( buf[2] << 8 ) | buf[3];
chal_len = ( buf[4] << 8 ) | buf[5];
SSL_DEBUG_MSG( 3, ( "ciph_len: %d, sess_len: %d, chal_len: %d",
ciph_len, sess_len, chal_len ) );
/*
* Make sure each parameter length is valid
*/
if( ciph_len < 3 || ( ciph_len % 3 ) != 0 )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
if( sess_len > 32 )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
if( chal_len < 8 || chal_len > 32 )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
if( n != 6 + ciph_len + sess_len + chal_len )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
SSL_DEBUG_BUF( 3, "client hello, ciphersuitelist",
buf + 6, ciph_len );
SSL_DEBUG_BUF( 3, "client hello, session id",
buf + 6 + ciph_len, sess_len );
SSL_DEBUG_BUF( 3, "client hello, challenge",
buf + 6 + ciph_len + sess_len, chal_len );
p = buf + 6 + ciph_len;
ssl->session_negotiate->length = sess_len;
memset( ssl->session_negotiate->id, 0, sizeof( ssl->session_negotiate->id ) );
memcpy( ssl->session_negotiate->id, p, ssl->session_negotiate->length );
p += sess_len;
memset( ssl->handshake->randbytes, 0, 64 );
memcpy( ssl->handshake->randbytes + 32 - chal_len, p, chal_len );
/*
* Check for TLS_EMPTY_RENEGOTIATION_INFO_SCSV
*/
for( i = 0, p = buf + 6; i < ciph_len; i += 3, p += 3 )
{
if( p[0] == 0 && p[1] == 0 && p[2] == SSL_EMPTY_RENEGOTIATION_INFO )
{
SSL_DEBUG_MSG( 3, ( "received TLS_EMPTY_RENEGOTIATION_INFO " ) );
if( ssl->renegotiation == SSL_RENEGOTIATION )
{
SSL_DEBUG_MSG( 1, ( "received RENEGOTIATION SCSV during renegotiation" ) );
if( ( ret = ssl_send_fatal_handshake_failure( ssl ) ) != 0 )
return( ret );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
ssl->secure_renegotiation = SSL_SECURE_RENEGOTIATION;
break;
}
}
for( i = 0; ssl->ciphersuites[i] != 0; i++ )
{
for( j = 0, p = buf + 6; j < ciph_len; j += 3, p += 3 )
{
if( p[0] == 0 &&
p[1] == 0 &&
p[2] == ssl->ciphersuites[i] )
goto have_ciphersuite_v2;
}
}
SSL_DEBUG_MSG( 1, ( "got no ciphersuites in common" ) );
return( POLARSSL_ERR_SSL_NO_CIPHER_CHOSEN );
have_ciphersuite_v2:
ssl->session_negotiate->ciphersuite = ssl->ciphersuites[i];
ssl_optimize_checksum( ssl, ssl->session_negotiate->ciphersuite );
/*
* SSLv2 Client Hello relevant renegotiation security checks
*/
if( ssl->secure_renegotiation == SSL_LEGACY_RENEGOTIATION &&
ssl->allow_legacy_renegotiation == SSL_LEGACY_BREAK_HANDSHAKE )
{
SSL_DEBUG_MSG( 1, ( "legacy renegotiation, breaking off handshake" ) );
if( ( ret = ssl_send_fatal_handshake_failure( ssl ) ) != 0 )
return( ret );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
ssl->in_left = 0;
ssl->state++;
SSL_DEBUG_MSG( 2, ( "<= parse client hello v2" ) );
return( 0 );
}
#endif /* POLARSSL_SSL_SRV_SUPPORT_SSLV2_CLIENT_HELLO */
static int ssl_parse_client_hello( ssl_context *ssl )
{
int ret;
unsigned int i, j;
size_t n;
unsigned int ciph_len, sess_len;
unsigned int comp_len;
unsigned int ext_len = 0;
unsigned char *buf, *p, *ext;
int renegotiation_info_seen = 0;
int handshake_failure = 0;
SSL_DEBUG_MSG( 2, ( "=> parse client hello" ) );
if( ssl->renegotiation == SSL_INITIAL_HANDSHAKE &&
( ret = ssl_fetch_input( ssl, 5 ) ) != 0 )
{
SSL_DEBUG_RET( 1, "ssl_fetch_input", ret );
return( ret );
}
buf = ssl->in_hdr;
#if defined(POLARSSL_SSL_SRV_SUPPORT_SSLV2_CLIENT_HELLO)
if( ( buf[0] & 0x80 ) != 0 )
return ssl_parse_client_hello_v2( ssl );
#endif
SSL_DEBUG_BUF( 4, "record header", buf, 5 );
SSL_DEBUG_MSG( 3, ( "client hello v3, message type: %d",
buf[0] ) );
SSL_DEBUG_MSG( 3, ( "client hello v3, message len.: %d",
( buf[3] << 8 ) | buf[4] ) );
SSL_DEBUG_MSG( 3, ( "client hello v3, protocol ver: [%d:%d]",
buf[1], buf[2] ) );
/*
* SSLv3 Client Hello
*
* Record layer:
* 0 . 0 message type
* 1 . 2 protocol version
* 3 . 4 message length
*/
if( buf[0] != SSL_MSG_HANDSHAKE ||
buf[1] != SSL_MAJOR_VERSION_3 )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
n = ( buf[3] << 8 ) | buf[4];
if( n < 45 || n > 512 )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
if( ssl->renegotiation == SSL_INITIAL_HANDSHAKE &&
( ret = ssl_fetch_input( ssl, 5 + n ) ) != 0 )
{
SSL_DEBUG_RET( 1, "ssl_fetch_input", ret );
return( ret );
}
buf = ssl->in_msg;
if( !ssl->renegotiation )
n = ssl->in_left - 5;
else
n = ssl->in_msglen;
ssl->handshake->update_checksum( ssl, buf, n );
/*
* SSL layer:
* 0 . 0 handshake type
* 1 . 3 handshake length
* 4 . 5 protocol version
* 6 . 9 UNIX time()
* 10 . 37 random bytes
* 38 . 38 session id length
* 39 . 38+x session id
* 39+x . 40+x ciphersuitelist length
* 41+x . .. ciphersuitelist
* .. . .. compression alg.
* .. . .. extensions
*/
SSL_DEBUG_BUF( 4, "record contents", buf, n );
SSL_DEBUG_MSG( 3, ( "client hello v3, handshake type: %d",
buf[0] ) );
SSL_DEBUG_MSG( 3, ( "client hello v3, handshake len.: %d",
( buf[1] << 16 ) | ( buf[2] << 8 ) | buf[3] ) );
SSL_DEBUG_MSG( 3, ( "client hello v3, max. version: [%d:%d]",
buf[4], buf[5] ) );
/*
* Check the handshake type and protocol version
*/
if( buf[0] != SSL_HS_CLIENT_HELLO ||
buf[4] != SSL_MAJOR_VERSION_3 )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
ssl->major_ver = SSL_MAJOR_VERSION_3;
ssl->minor_ver = ( buf[5] <= SSL_MINOR_VERSION_3 )
? buf[5] : SSL_MINOR_VERSION_3;
if( ssl->minor_ver < ssl->min_minor_ver )
{
SSL_DEBUG_MSG( 1, ( "client only supports ssl smaller than minimum"
" [%d:%d] < [%d:%d]", ssl->major_ver, ssl->minor_ver,
ssl->min_major_ver, ssl->min_minor_ver ) );
ssl_send_alert_message( ssl, SSL_ALERT_LEVEL_FATAL,
SSL_ALERT_MSG_PROTOCOL_VERSION );
return( POLARSSL_ERR_SSL_BAD_HS_PROTOCOL_VERSION );
}
ssl->max_major_ver = buf[4];
ssl->max_minor_ver = buf[5];
memcpy( ssl->handshake->randbytes, buf + 6, 32 );
/*
* Check the handshake message length
*/
if( buf[1] != 0 || n != (unsigned int) 4 + ( ( buf[2] << 8 ) | buf[3] ) )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
/*
* Check the session length
*/
sess_len = buf[38];
if( sess_len > 32 )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
ssl->session_negotiate->length = sess_len;
memset( ssl->session_negotiate->id, 0,
sizeof( ssl->session_negotiate->id ) );
memcpy( ssl->session_negotiate->id, buf + 39,
ssl->session_negotiate->length );
/*
* Check the ciphersuitelist length
*/
ciph_len = ( buf[39 + sess_len] << 8 )
| ( buf[40 + sess_len] );
if( ciph_len < 2 || ciph_len > 256 || ( ciph_len % 2 ) != 0 )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
/*
* Check the compression algorithms length
*/
comp_len = buf[41 + sess_len + ciph_len];
if( comp_len < 1 || comp_len > 16 )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
/*
* Check the extension length
*/
if( n > 42 + sess_len + ciph_len + comp_len )
{
ext_len = ( buf[42 + sess_len + ciph_len + comp_len] << 8 )
| ( buf[43 + sess_len + ciph_len + comp_len] );
if( ( ext_len > 0 && ext_len < 4 ) ||
n != 44 + sess_len + ciph_len + comp_len + ext_len )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
SSL_DEBUG_BUF( 3, "Ext", buf + 44 + sess_len + ciph_len + comp_len, ext_len);
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
}
ssl->session_negotiate->compression = SSL_COMPRESS_NULL;
#if defined(POLARSSL_ZLIB_SUPPORT)
for( i = 0; i < comp_len; ++i )
{
if( buf[42 + sess_len + ciph_len + i] == SSL_COMPRESS_DEFLATE )
{
ssl->session_negotiate->compression = SSL_COMPRESS_DEFLATE;
break;
}
}
#endif
SSL_DEBUG_BUF( 3, "client hello, random bytes",
buf + 6, 32 );
SSL_DEBUG_BUF( 3, "client hello, session id",
buf + 38, sess_len );
SSL_DEBUG_BUF( 3, "client hello, ciphersuitelist",
buf + 41 + sess_len, ciph_len );
SSL_DEBUG_BUF( 3, "client hello, compression",
buf + 42 + sess_len + ciph_len, comp_len );
/*
* Check for TLS_EMPTY_RENEGOTIATION_INFO_SCSV
*/
for( i = 0, p = buf + 41 + sess_len; i < ciph_len; i += 2, p += 2 )
{
if( p[0] == 0 && p[1] == SSL_EMPTY_RENEGOTIATION_INFO )
{
SSL_DEBUG_MSG( 3, ( "received TLS_EMPTY_RENEGOTIATION_INFO " ) );
if( ssl->renegotiation == SSL_RENEGOTIATION )
{
SSL_DEBUG_MSG( 1, ( "received RENEGOTIATION SCSV during renegotiation" ) );
if( ( ret = ssl_send_fatal_handshake_failure( ssl ) ) != 0 )
return( ret );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
ssl->secure_renegotiation = SSL_SECURE_RENEGOTIATION;
break;
}
}
/*
* Search for a matching ciphersuite
*/
for( i = 0; ssl->ciphersuites[i] != 0; i++ )
{
for( j = 0, p = buf + 41 + sess_len; j < ciph_len;
j += 2, p += 2 )
{
if( p[0] == 0 && p[1] == ssl->ciphersuites[i] )
goto have_ciphersuite;
}
}
SSL_DEBUG_MSG( 1, ( "got no ciphersuites in common" ) );
return( POLARSSL_ERR_SSL_NO_CIPHER_CHOSEN );
have_ciphersuite:
ssl->session_negotiate->ciphersuite = ssl->ciphersuites[i];
ssl_optimize_checksum( ssl, ssl->session_negotiate->ciphersuite );
ext = buf + 44 + sess_len + ciph_len + comp_len;
while( ext_len )
{
unsigned int ext_id = ( ( ext[0] << 8 )
| ( ext[1] ) );
unsigned int ext_size = ( ( ext[2] << 8 )
| ( ext[3] ) );
if( ext_size + 4 > ext_len )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
switch( ext_id )
{
case TLS_EXT_SERVERNAME:
SSL_DEBUG_MSG( 3, ( "found ServerName extension" ) );
if( ssl->f_sni == NULL )
break;
ret = ssl_parse_servername_ext( ssl, ext + 4, ext_size );
if( ret != 0 )
return( ret );
break;
case TLS_EXT_RENEGOTIATION_INFO:
SSL_DEBUG_MSG( 3, ( "found renegotiation extension" ) );
renegotiation_info_seen = 1;
ret = ssl_parse_renegotiation_info( ssl, ext + 4, ext_size );
if( ret != 0 )
return( ret );
break;
case TLS_EXT_SIG_ALG:
SSL_DEBUG_MSG( 3, ( "found signature_algorithms extension" ) );
if( ssl->renegotiation == SSL_RENEGOTIATION )
break;
ret = ssl_parse_signature_algorithms_ext( ssl, ext + 4, ext_size );
if( ret != 0 )
return( ret );
break;
default:
SSL_DEBUG_MSG( 3, ( "unknown extension found: %d (ignoring)",
ext_id ) );
}
ext_len -= 4 + ext_size;
ext += 4 + ext_size;
if( ext_len > 0 && ext_len < 4 )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
}
/*
* Renegotiation security checks
*/
if( ssl->secure_renegotiation == SSL_LEGACY_RENEGOTIATION &&
ssl->allow_legacy_renegotiation == SSL_LEGACY_BREAK_HANDSHAKE )
{
SSL_DEBUG_MSG( 1, ( "legacy renegotiation, breaking off handshake" ) );
handshake_failure = 1;
}
else if( ssl->renegotiation == SSL_RENEGOTIATION &&
ssl->secure_renegotiation == SSL_SECURE_RENEGOTIATION &&
renegotiation_info_seen == 0 )
{
SSL_DEBUG_MSG( 1, ( "renegotiation_info extension missing (secure)" ) );
handshake_failure = 1;
}
else if( ssl->renegotiation == SSL_RENEGOTIATION &&
ssl->secure_renegotiation == SSL_LEGACY_RENEGOTIATION &&
ssl->allow_legacy_renegotiation == SSL_LEGACY_NO_RENEGOTIATION )
{
SSL_DEBUG_MSG( 1, ( "legacy renegotiation not allowed" ) );
handshake_failure = 1;
}
else if( ssl->renegotiation == SSL_RENEGOTIATION &&
ssl->secure_renegotiation == SSL_LEGACY_RENEGOTIATION &&
renegotiation_info_seen == 1 )
{
SSL_DEBUG_MSG( 1, ( "renegotiation_info extension present (legacy)" ) );
handshake_failure = 1;
}
if( handshake_failure == 1 )
{
if( ( ret = ssl_send_fatal_handshake_failure( ssl ) ) != 0 )
return( ret );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
ssl->in_left = 0;
ssl->state++;
SSL_DEBUG_MSG( 2, ( "<= parse client hello" ) );
return( 0 );
}
static int ssl_write_server_hello( ssl_context *ssl )
{
time_t t;
int ret, n;
size_t ext_len = 0;
unsigned char *buf, *p;
SSL_DEBUG_MSG( 2, ( "=> write server hello" ) );
/*
* 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;
*p++ = (unsigned char) ssl->major_ver;
*p++ = (unsigned char) ssl->minor_ver;
SSL_DEBUG_MSG( 3, ( "server hello, chosen version: [%d:%d]",
buf[4], buf[5] ) );
t = time( NULL );
*p++ = (unsigned char)( t >> 24 );
*p++ = (unsigned char)( t >> 16 );
*p++ = (unsigned char)( t >> 8 );
*p++ = (unsigned char)( t );
SSL_DEBUG_MSG( 3, ( "server hello, current time: %lu", t ) );
if( ( ret = ssl->f_rng( ssl->p_rng, p, 28 ) ) != 0 )
return( ret );
p += 28;
memcpy( ssl->handshake->randbytes + 32, buf + 6, 32 );
SSL_DEBUG_BUF( 3, "server hello, random bytes", buf + 6, 32 );
/*
* 38 . 38 session id length
* 39 . 38+n session id
* 39+n . 40+n chosen ciphersuite
* 41+n . 41+n chosen compression alg.
*/
ssl->session_negotiate->length = n = 32;
*p++ = (unsigned char) ssl->session_negotiate->length;
if( ssl->renegotiation != SSL_INITIAL_HANDSHAKE ||
ssl->f_get_cache == NULL ||
ssl->f_get_cache( ssl->p_get_cache, ssl->session_negotiate ) != 0 )
{
/*
* Not found, create a new session id
*/
ssl->handshake->resume = 0;
ssl->state++;
if( ( ret = ssl->f_rng( ssl->p_rng, ssl->session_negotiate->id,
n ) ) != 0 )
return( ret );
}
else
{
/*
* Found a matching session, resuming it
*/
ssl->handshake->resume = 1;
ssl->state = SSL_SERVER_CHANGE_CIPHER_SPEC;
if( ( ret = ssl_derive_keys( ssl ) ) != 0 )
{
SSL_DEBUG_RET( 1, "ssl_derive_keys", ret );
return( ret );
}
}
memcpy( p, ssl->session_negotiate->id, ssl->session_negotiate->length );
p += ssl->session_negotiate->length;
SSL_DEBUG_MSG( 3, ( "server hello, session id len.: %d", n ) );
SSL_DEBUG_BUF( 3, "server hello, session id", buf + 39, n );
SSL_DEBUG_MSG( 3, ( "%s session has been resumed",
ssl->handshake->resume ? "a" : "no" ) );
*p++ = (unsigned char)( ssl->session_negotiate->ciphersuite >> 8 );
*p++ = (unsigned char)( ssl->session_negotiate->ciphersuite );
*p++ = (unsigned char)( ssl->session_negotiate->compression );
SSL_DEBUG_MSG( 3, ( "server hello, chosen ciphersuite: %d",
ssl->session_negotiate->ciphersuite ) );
SSL_DEBUG_MSG( 3, ( "server hello, compress alg.: %d",
ssl->session_negotiate->compression ) );
SSL_DEBUG_MSG( 3, ( "server hello, prepping for secure renegotiation extension" ) );
ext_len += 5 + ssl->verify_data_len * 2;
SSL_DEBUG_MSG( 3, ( "server hello, total extension length: %d",
ext_len ) );
*p++ = (unsigned char)( ( ext_len >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( ext_len ) & 0xFF );
/*
* Secure renegotiation
*/
SSL_DEBUG_MSG( 3, ( "client hello, secure renegotiation extension" ) );
*p++ = (unsigned char)( ( TLS_EXT_RENEGOTIATION_INFO >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( TLS_EXT_RENEGOTIATION_INFO ) & 0xFF );
*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;
ssl->out_msglen = p - buf;
ssl->out_msgtype = SSL_MSG_HANDSHAKE;
ssl->out_msg[0] = SSL_HS_SERVER_HELLO;
ret = ssl_write_record( ssl );
SSL_DEBUG_MSG( 2, ( "<= write server hello" ) );
return( ret );
}
static int ssl_write_certificate_request( ssl_context *ssl )
{
int ret;
size_t n = 0, dn_size, total_dn_size;
unsigned char *buf, *p;
const x509_cert *crt;
SSL_DEBUG_MSG( 2, ( "=> write certificate request" ) );
ssl->state++;
if( ssl->authmode == SSL_VERIFY_NONE )
{
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;
/*
* At the moment, only RSA certificates are supported
*/
*p++ = 1;
*p++ = SSL_CERT_TYPE_RSA_SIGN;
/*
* Add signature_algorithms for verify (TLS 1.2)
* Only add current running algorithm that is already required for
* requested ciphersuite.
*
* Length is always 2
*/
if( ssl->minor_ver == SSL_MINOR_VERSION_3 )
{
ssl->handshake->verify_sig_alg = SSL_HASH_SHA256;
*p++ = 0;
*p++ = 2;
if( ssl->session_negotiate->ciphersuite == TLS_RSA_WITH_AES_256_GCM_SHA384 ||
ssl->session_negotiate->ciphersuite == TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 )
{
ssl->handshake->verify_sig_alg = SSL_HASH_SHA384;
}
*p++ = ssl->handshake->verify_sig_alg;
*p++ = SSL_SIG_RSA;
n += 4;
}
p += 2;
crt = ssl->ca_chain;
total_dn_size = 0;
while( crt != NULL )
{
if( p - buf > 4096 )
break;
dn_size = crt->subject_raw.len;
*p++ = (unsigned char)( dn_size >> 8 );
*p++ = (unsigned char)( dn_size );
memcpy( p, crt->subject_raw.p, dn_size );
p += dn_size;
SSL_DEBUG_BUF( 3, "requested DN", p, dn_size );
total_dn_size += 2 + dn_size;
crt = crt->next;
}
ssl->out_msglen = p - buf;
ssl->out_msgtype = SSL_MSG_HANDSHAKE;
ssl->out_msg[0] = SSL_HS_CERTIFICATE_REQUEST;
ssl->out_msg[6 + n] = (unsigned char)( total_dn_size >> 8 );
ssl->out_msg[7 + n] = (unsigned char)( total_dn_size );
ret = ssl_write_record( ssl );
SSL_DEBUG_MSG( 2, ( "<= write certificate request" ) );
return( ret );
}
static int ssl_write_server_key_exchange( ssl_context *ssl )
{
#if defined(POLARSSL_DHM_C)
int ret;
size_t n, rsa_key_len = 0;
unsigned char hash[64];
int hash_id = 0;
unsigned int hashlen = 0;
#endif
SSL_DEBUG_MSG( 2, ( "=> write server key exchange" ) );
if( ssl->session_negotiate->ciphersuite != TLS_DHE_RSA_WITH_DES_CBC_SHA &&
ssl->session_negotiate->ciphersuite != TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA &&
ssl->session_negotiate->ciphersuite != TLS_DHE_RSA_WITH_AES_128_CBC_SHA &&
ssl->session_negotiate->ciphersuite != TLS_DHE_RSA_WITH_AES_256_CBC_SHA &&
ssl->session_negotiate->ciphersuite != TLS_DHE_RSA_WITH_AES_128_CBC_SHA256 &&
ssl->session_negotiate->ciphersuite != TLS_DHE_RSA_WITH_AES_256_CBC_SHA256 &&
ssl->session_negotiate->ciphersuite != TLS_DHE_RSA_WITH_CAMELLIA_128_CBC_SHA &&
ssl->session_negotiate->ciphersuite != TLS_DHE_RSA_WITH_CAMELLIA_256_CBC_SHA &&
ssl->session_negotiate->ciphersuite != TLS_DHE_RSA_WITH_CAMELLIA_128_CBC_SHA256 &&
ssl->session_negotiate->ciphersuite != TLS_DHE_RSA_WITH_CAMELLIA_256_CBC_SHA256 &&
ssl->session_negotiate->ciphersuite != TLS_DHE_RSA_WITH_AES_128_GCM_SHA256 &&
ssl->session_negotiate->ciphersuite != TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 )
{
SSL_DEBUG_MSG( 2, ( "<= skip write server key exchange" ) );
ssl->state++;
return( 0 );
}
#if !defined(POLARSSL_DHM_C)
SSL_DEBUG_MSG( 1, ( "support for dhm is not available" ) );
return( POLARSSL_ERR_SSL_FEATURE_UNAVAILABLE );
#else
if( ssl->rsa_key == NULL )
{
SSL_DEBUG_MSG( 1, ( "got no private key" ) );
return( POLARSSL_ERR_SSL_PRIVATE_KEY_REQUIRED );
}
/*
* 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 = mpi_copy( &ssl->handshake->dhm_ctx.P, &ssl->dhm_P ) ) != 0 ||
( ret = mpi_copy( &ssl->handshake->dhm_ctx.G, &ssl->dhm_G ) ) != 0 )
{
SSL_DEBUG_RET( 1, "mpi_copy", ret );
return( ret );
}
if( ( ret = dhm_make_params( &ssl->handshake->dhm_ctx,
mpi_size( &ssl->handshake->dhm_ctx.P ),
ssl->out_msg + 4,
&n, ssl->f_rng, ssl->p_rng ) ) != 0 )
{
SSL_DEBUG_RET( 1, "dhm_make_params", ret );
return( ret );
}
SSL_DEBUG_MPI( 3, "DHM: X ", &ssl->handshake->dhm_ctx.X );
SSL_DEBUG_MPI( 3, "DHM: P ", &ssl->handshake->dhm_ctx.P );
SSL_DEBUG_MPI( 3, "DHM: G ", &ssl->handshake->dhm_ctx.G );
SSL_DEBUG_MPI( 3, "DHM: GX", &ssl->handshake->dhm_ctx.GX );
if( ssl->minor_ver != SSL_MINOR_VERSION_3 )
{
md5_context md5;
sha1_context sha1;
/*
* digitally-signed struct {
* opaque md5_hash[16];
* opaque sha_hash[20];
* };
*
* md5_hash
* MD5(ClientHello.random + ServerHello.random
* + ServerParams);
* sha_hash
* SHA(ClientHello.random + ServerHello.random
* + ServerParams);
*/
md5_starts( &md5 );
md5_update( &md5, ssl->handshake->randbytes, 64 );
md5_update( &md5, ssl->out_msg + 4, n );
md5_finish( &md5, hash );
sha1_starts( &sha1 );
sha1_update( &sha1, ssl->handshake->randbytes, 64 );
sha1_update( &sha1, ssl->out_msg + 4, n );
sha1_finish( &sha1, hash + 16 );
hashlen = 36;
hash_id = SIG_RSA_RAW;
}
else
{
/*
* digitally-signed struct {
* opaque client_random[32];
* opaque server_random[32];
* ServerDHParams params;
* };
*/
#if defined(POLARSSL_SHA4_C)
if( ssl->handshake->sig_alg == SSL_HASH_SHA512 )
{
sha4_context sha4;
sha4_starts( &sha4, 0 );
sha4_update( &sha4, ssl->handshake->randbytes, 64 );
sha4_update( &sha4, ssl->out_msg + 4, n );
sha4_finish( &sha4, hash );
hashlen = 64;
hash_id = SIG_RSA_SHA512;
}
else if( ssl->handshake->sig_alg == SSL_HASH_SHA384 )
{
sha4_context sha4;
sha4_starts( &sha4, 1 );
sha4_update( &sha4, ssl->handshake->randbytes, 64 );
sha4_update( &sha4, ssl->out_msg + 4, n );
sha4_finish( &sha4, hash );
hashlen = 48;
hash_id = SIG_RSA_SHA384;
}
else
#endif
#if defined(POLARSSL_SHA2_C)
if( ssl->handshake->sig_alg == SSL_HASH_SHA256 )
{
sha2_context sha2;
sha2_starts( &sha2, 0 );
sha2_update( &sha2, ssl->handshake->randbytes, 64 );
sha2_update( &sha2, ssl->out_msg + 4, n );
sha2_finish( &sha2, hash );
hashlen = 32;
hash_id = SIG_RSA_SHA256;
}
else if( ssl->handshake->sig_alg == SSL_HASH_SHA224 )
{
sha2_context sha2;
sha2_starts( &sha2, 1 );
sha2_update( &sha2, ssl->handshake->randbytes, 64 );
sha2_update( &sha2, ssl->out_msg + 4, n );
sha2_finish( &sha2, hash );
hashlen = 24;
hash_id = SIG_RSA_SHA224;
}
else
#endif
if( ssl->handshake->sig_alg == SSL_HASH_SHA1 )
{
sha1_context sha1;
sha1_starts( &sha1 );
sha1_update( &sha1, ssl->handshake->randbytes, 64 );
sha1_update( &sha1, ssl->out_msg + 4, n );
sha1_finish( &sha1, hash );
hashlen = 20;
hash_id = SIG_RSA_SHA1;
}
else if( ssl->handshake->sig_alg == SSL_HASH_MD5 )
{
md5_context md5;
md5_starts( &md5 );
md5_update( &md5, ssl->handshake->randbytes, 64 );
md5_update( &md5, ssl->out_msg + 4, n );
md5_finish( &md5, hash );
hashlen = 16;
hash_id = SIG_RSA_MD5;
}
}
SSL_DEBUG_BUF( 3, "parameters hash", hash, hashlen );
if ( ssl->rsa_key )
rsa_key_len = ssl->rsa_key_len( ssl->rsa_key );
if( ssl->minor_ver == SSL_MINOR_VERSION_3 )
{
ssl->out_msg[4 + n] = ssl->handshake->sig_alg;
ssl->out_msg[5 + n] = SSL_SIG_RSA;
n += 2;
}
ssl->out_msg[4 + n] = (unsigned char)( rsa_key_len >> 8 );
ssl->out_msg[5 + n] = (unsigned char)( rsa_key_len );
if ( ssl->rsa_key )
{
ret = ssl->rsa_sign( ssl->rsa_key, ssl->f_rng, ssl->p_rng,
RSA_PRIVATE,
hash_id, hashlen, hash,
ssl->out_msg + 6 + n );
}
if( ret != 0 )
{
SSL_DEBUG_RET( 1, "pkcs1_sign", ret );
return( ret );
}
SSL_DEBUG_BUF( 3, "my RSA sig", ssl->out_msg + 6 + n, rsa_key_len );
ssl->out_msglen = 6 + n + rsa_key_len;
ssl->out_msgtype = SSL_MSG_HANDSHAKE;
ssl->out_msg[0] = SSL_HS_SERVER_KEY_EXCHANGE;
ssl->state++;
if( ( ret = ssl_write_record( ssl ) ) != 0 )
{
SSL_DEBUG_RET( 1, "ssl_write_record", ret );
return( ret );
}
SSL_DEBUG_MSG( 2, ( "<= write server key exchange" ) );
return( 0 );
#endif
}
static int ssl_write_server_hello_done( ssl_context *ssl )
{
int ret;
SSL_DEBUG_MSG( 2, ( "=> write server hello done" ) );
ssl->out_msglen = 4;
ssl->out_msgtype = SSL_MSG_HANDSHAKE;
ssl->out_msg[0] = SSL_HS_SERVER_HELLO_DONE;
ssl->state++;
if( ( ret = ssl_write_record( ssl ) ) != 0 )
{
SSL_DEBUG_RET( 1, "ssl_write_record", ret );
return( ret );
}
SSL_DEBUG_MSG( 2, ( "<= write server hello done" ) );
return( 0 );
}
static int ssl_parse_client_key_exchange( ssl_context *ssl )
{
int ret;
size_t i, n = 0;
SSL_DEBUG_MSG( 2, ( "=> parse client key exchange" ) );
if( ( ret = ssl_read_record( ssl ) ) != 0 )
{
SSL_DEBUG_RET( 1, "ssl_read_record", ret );
return( ret );
}
if( ssl->in_msgtype != SSL_MSG_HANDSHAKE )
{
SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
}
if( ssl->in_msg[0] != SSL_HS_CLIENT_KEY_EXCHANGE )
{
SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
}
if( ssl->session_negotiate->ciphersuite == TLS_DHE_RSA_WITH_DES_CBC_SHA ||
ssl->session_negotiate->ciphersuite == TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA ||
ssl->session_negotiate->ciphersuite == TLS_DHE_RSA_WITH_AES_128_CBC_SHA ||
ssl->session_negotiate->ciphersuite == TLS_DHE_RSA_WITH_AES_256_CBC_SHA ||
ssl->session_negotiate->ciphersuite == TLS_DHE_RSA_WITH_AES_128_CBC_SHA256 ||
ssl->session_negotiate->ciphersuite == TLS_DHE_RSA_WITH_AES_256_CBC_SHA256 ||
ssl->session_negotiate->ciphersuite == TLS_DHE_RSA_WITH_CAMELLIA_128_CBC_SHA ||
ssl->session_negotiate->ciphersuite == TLS_DHE_RSA_WITH_CAMELLIA_256_CBC_SHA ||
ssl->session_negotiate->ciphersuite == TLS_DHE_RSA_WITH_CAMELLIA_128_CBC_SHA256 ||
ssl->session_negotiate->ciphersuite == TLS_DHE_RSA_WITH_CAMELLIA_256_CBC_SHA256 ||
ssl->session_negotiate->ciphersuite == TLS_DHE_RSA_WITH_AES_128_GCM_SHA256 ||
ssl->session_negotiate->ciphersuite == TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 )
{
#if !defined(POLARSSL_DHM_C)
SSL_DEBUG_MSG( 1, ( "support for dhm is not available" ) );
return( POLARSSL_ERR_SSL_FEATURE_UNAVAILABLE );
#else
/*
* Receive G^Y mod P, premaster = (G^Y)^X mod P
*/
n = ( ssl->in_msg[4] << 8 ) | ssl->in_msg[5];
if( n < 1 || n > ssl->handshake->dhm_ctx.len ||
n + 6 != ssl->in_hslen )
{
SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
}
if( ( ret = dhm_read_public( &ssl->handshake->dhm_ctx,
ssl->in_msg + 6, n ) ) != 0 )
{
SSL_DEBUG_RET( 1, "dhm_read_public", ret );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_DHM_RP );
}
SSL_DEBUG_MPI( 3, "DHM: GY", &ssl->handshake->dhm_ctx.GY );
ssl->handshake->pmslen = ssl->handshake->dhm_ctx.len;
if( ( ret = dhm_calc_secret( &ssl->handshake->dhm_ctx,
ssl->handshake->premaster,
&ssl->handshake->pmslen ) ) != 0 )
{
SSL_DEBUG_RET( 1, "dhm_calc_secret", ret );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_DHM_CS );
}
SSL_DEBUG_MPI( 3, "DHM: K ", &ssl->handshake->dhm_ctx.K );
#endif
}
else
{
if( ssl->rsa_key == NULL )
{
SSL_DEBUG_MSG( 1, ( "got no private key" ) );
return( POLARSSL_ERR_SSL_PRIVATE_KEY_REQUIRED );
}
/*
* Decrypt the premaster using own private RSA key
*/
i = 4;
if( ssl->rsa_key )
n = ssl->rsa_key_len( ssl->rsa_key );
ssl->handshake->pmslen = 48;
if( ssl->minor_ver != SSL_MINOR_VERSION_0 )
{
i += 2;
if( ssl->in_msg[4] != ( ( n >> 8 ) & 0xFF ) ||
ssl->in_msg[5] != ( ( n ) & 0xFF ) )
{
SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
}
}
if( ssl->in_hslen != i + n )
{
SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
}
if( ssl->rsa_key ) {
ret = ssl->rsa_decrypt( ssl->rsa_key, RSA_PRIVATE,
&ssl->handshake->pmslen,
ssl->in_msg + i,
ssl->handshake->premaster,
sizeof(ssl->handshake->premaster) );
}
if( ret != 0 || ssl->handshake->pmslen != 48 ||
ssl->handshake->premaster[0] != ssl->max_major_ver ||
ssl->handshake->premaster[1] != ssl->max_minor_ver )
{
SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
/*
* 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.
*/
ssl->handshake->pmslen = 48;
ret = ssl->f_rng( ssl->p_rng, ssl->handshake->premaster,
ssl->handshake->pmslen );
if( ret != 0 )
return( ret );
}
}
if( ( ret = ssl_derive_keys( ssl ) ) != 0 )
{
SSL_DEBUG_RET( 1, "ssl_derive_keys", ret );
return( ret );
}
ssl->state++;
SSL_DEBUG_MSG( 2, ( "<= parse client key exchange" ) );
return( 0 );
}
static int ssl_parse_certificate_verify( ssl_context *ssl )
{
int ret;
size_t n = 0, n1, n2;
unsigned char hash[48];
int hash_id;
unsigned int hashlen;
SSL_DEBUG_MSG( 2, ( "=> parse certificate verify" ) );
if( ssl->session_negotiate->peer_cert == NULL )
{
SSL_DEBUG_MSG( 2, ( "<= skip parse certificate verify" ) );
ssl->state++;
return( 0 );
}
ssl->handshake->calc_verify( ssl, hash );
if( ( ret = ssl_read_record( ssl ) ) != 0 )
{
SSL_DEBUG_RET( 1, "ssl_read_record", ret );
return( ret );
}
ssl->state++;
if( ssl->in_msgtype != SSL_MSG_HANDSHAKE )
{
SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
}
if( ssl->in_msg[0] != SSL_HS_CERTIFICATE_VERIFY )
{
SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
}
if( ssl->minor_ver == SSL_MINOR_VERSION_3 )
{
/*
* As server we know we either have SSL_HASH_SHA384 or
* SSL_HASH_SHA256
*/
if( ssl->in_msg[4] != ssl->handshake->verify_sig_alg ||
ssl->in_msg[5] != SSL_SIG_RSA )
{
SSL_DEBUG_MSG( 1, ( "peer not adhering to requested sig_alg for verify message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
}
if( ssl->handshake->verify_sig_alg == SSL_HASH_SHA384 )
{
hashlen = 48;
hash_id = SIG_RSA_SHA384;
}
else
{
hashlen = 32;
hash_id = SIG_RSA_SHA256;
}
n += 2;
}
else
{
hashlen = 36;
hash_id = SIG_RSA_RAW;
}
n1 = ssl->session_negotiate->peer_cert->rsa.len;
n2 = ( ssl->in_msg[4 + n] << 8 ) | ssl->in_msg[5 + n];
if( n + n1 + 6 != ssl->in_hslen || n1 != n2 )
{
SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
}
ret = rsa_pkcs1_verify( &ssl->session_negotiate->peer_cert->rsa, RSA_PUBLIC,
hash_id, hashlen, hash, ssl->in_msg + 6 + n );
if( ret != 0 )
{
SSL_DEBUG_RET( 1, "rsa_pkcs1_verify", ret );
return( ret );
}
SSL_DEBUG_MSG( 2, ( "<= parse certificate verify" ) );
return( 0 );
}
/*
* SSL handshake -- server side -- single step
*/
int ssl_handshake_server_step( ssl_context *ssl )
{
int ret = 0;
if( ssl->state == SSL_HANDSHAKE_OVER )
return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
SSL_DEBUG_MSG( 2, ( "server state: %d", ssl->state ) );
if( ( ret = ssl_flush_output( ssl ) ) != 0 )
return( ret );
switch( ssl->state )
{
case SSL_HELLO_REQUEST:
ssl->state = SSL_CLIENT_HELLO;
break;
/*
* <== ClientHello
*/
case SSL_CLIENT_HELLO:
ret = ssl_parse_client_hello( ssl );
break;
/*
* ==> ServerHello
* Certificate
* ( ServerKeyExchange )
* ( CertificateRequest )
* ServerHelloDone
*/
case SSL_SERVER_HELLO:
ret = ssl_write_server_hello( ssl );
break;
case SSL_SERVER_CERTIFICATE:
ret = ssl_write_certificate( ssl );
break;
case SSL_SERVER_KEY_EXCHANGE:
ret = ssl_write_server_key_exchange( ssl );
break;
case SSL_CERTIFICATE_REQUEST:
ret = ssl_write_certificate_request( ssl );
break;
case SSL_SERVER_HELLO_DONE:
ret = ssl_write_server_hello_done( ssl );
break;
/*
* <== ( Certificate/Alert )
* ClientKeyExchange
* ( CertificateVerify )
* ChangeCipherSpec
* Finished
*/
case SSL_CLIENT_CERTIFICATE:
ret = ssl_parse_certificate( ssl );
break;
case SSL_CLIENT_KEY_EXCHANGE:
ret = ssl_parse_client_key_exchange( ssl );
break;
case SSL_CERTIFICATE_VERIFY:
ret = ssl_parse_certificate_verify( ssl );
break;
case SSL_CLIENT_CHANGE_CIPHER_SPEC:
ret = ssl_parse_change_cipher_spec( ssl );
break;
case SSL_CLIENT_FINISHED:
ret = ssl_parse_finished( ssl );
break;
/*
* ==> ChangeCipherSpec
* Finished
*/
case SSL_SERVER_CHANGE_CIPHER_SPEC:
ret = ssl_write_change_cipher_spec( ssl );
break;
case SSL_SERVER_FINISHED:
ret = ssl_write_finished( ssl );
break;
case SSL_FLUSH_BUFFERS:
SSL_DEBUG_MSG( 2, ( "handshake: done" ) );
ssl->state = SSL_HANDSHAKE_WRAPUP;
break;
case SSL_HANDSHAKE_WRAPUP:
ssl_handshake_wrapup( ssl );
break;
default:
SSL_DEBUG_MSG( 1, ( "invalid state %d", ssl->state ) );
return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
}
return( ret );
}
#endif
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