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mbedtls/library/ssl_cli.c
Paul Bakker a1caf6e1e8 SSL now gracefully handles missing RNG
2014-07-07 14:20:52 +02:00

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/*
* SSLv3/TLSv1 client-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_CLI_C)
#include "polarssl/debug.h"
#include "polarssl/ssl.h"
#include <stdlib.h>
#include <stdio.h>
#include <time.h>
#if defined(POLARSSL_SHA4_C)
#include "polarssl/sha4.h"
#endif
static int ssl_write_client_hello( ssl_context *ssl )
{
int ret;
size_t i, n, ext_len = 0;
unsigned char *buf;
unsigned char *p;
time_t t;
unsigned char sig_alg_list[20];
size_t sig_alg_len = 0;
SSL_DEBUG_MSG( 2, ( "=> write client hello" ) );
if( ssl->f_rng == NULL )
{
SSL_DEBUG_MSG( 1, ( "no RNG provided") );
return( POLARSSL_ERR_SSL_NO_RNG );
}
if( ssl->renegotiation == SSL_INITIAL_HANDSHAKE )
{
ssl->major_ver = ssl->min_major_ver;
ssl->minor_ver = ssl->min_minor_ver;
}
if( ssl->max_major_ver == 0 && ssl->max_minor_ver == 0 )
{
ssl->max_major_ver = SSL_MAJOR_VERSION_3;
ssl->max_minor_ver = SSL_MINOR_VERSION_3;
}
/*
* 0 . 0 handshake type
* 1 . 3 handshake length
* 4 . 5 highest version supported
* 6 . 9 current UNIX time
* 10 . 37 random bytes
*/
buf = ssl->out_msg;
p = buf + 4;
*p++ = (unsigned char) ssl->max_major_ver;
*p++ = (unsigned char) ssl->max_minor_ver;
SSL_DEBUG_MSG( 3, ( "client hello, max 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, ( "client hello, current time: %lu", t ) );
if( ( ret = ssl->f_rng( ssl->p_rng, p, 28 ) ) != 0 )
return( ret );
p += 28;
memcpy( ssl->handshake->randbytes, buf + 6, 32 );
SSL_DEBUG_BUF( 3, "client hello, random bytes", buf + 6, 32 );
/*
* 38 . 38 session id length
* 39 . 39+n session id
* 40+n . 41+n ciphersuitelist length
* 42+n . .. ciphersuitelist
* .. . .. compression methods length
* .. . .. compression methods
* .. . .. extensions length
* .. . .. extensions
*/
n = ssl->session_negotiate->length;
if( ssl->renegotiation != SSL_INITIAL_HANDSHAKE || n < 16 || n > 32 ||
ssl->handshake->resume == 0 )
n = 0;
*p++ = (unsigned char) n;
for( i = 0; i < n; i++ )
*p++ = ssl->session_negotiate->id[i];
SSL_DEBUG_MSG( 3, ( "client hello, session id len.: %d", n ) );
SSL_DEBUG_BUF( 3, "client hello, session id", buf + 39, n );
for( n = 0; ssl->ciphersuites[ssl->minor_ver][n] != 0; n++ );
if( ssl->renegotiation == SSL_INITIAL_HANDSHAKE ) n++;
*p++ = (unsigned char)( n >> 7 );
*p++ = (unsigned char)( n << 1 );
/*
* Add TLS_EMPTY_RENEGOTIATION_INFO_SCSV
*/
if( ssl->renegotiation == SSL_INITIAL_HANDSHAKE )
{
*p++ = (unsigned char)( SSL_EMPTY_RENEGOTIATION_INFO >> 8 );
*p++ = (unsigned char)( SSL_EMPTY_RENEGOTIATION_INFO );
n--;
}
SSL_DEBUG_MSG( 3, ( "client hello, got %d ciphersuites", n ) );
for( i = 0; i < n; i++ )
{
SSL_DEBUG_MSG( 3, ( "client hello, add ciphersuite: %2d",
ssl->ciphersuites[ssl->minor_ver][i] ) );
*p++ = (unsigned char)( ssl->ciphersuites[ssl->minor_ver][i] >> 8 );
*p++ = (unsigned char)( ssl->ciphersuites[ssl->minor_ver][i] );
}
#if defined(POLARSSL_ZLIB_SUPPORT)
SSL_DEBUG_MSG( 3, ( "client hello, compress len.: %d", 2 ) );
SSL_DEBUG_MSG( 3, ( "client hello, compress alg.: %d %d",
SSL_COMPRESS_DEFLATE, SSL_COMPRESS_NULL ) );
*p++ = 2;
*p++ = SSL_COMPRESS_DEFLATE;
*p++ = SSL_COMPRESS_NULL;
#else
SSL_DEBUG_MSG( 3, ( "client hello, compress len.: %d", 1 ) );
SSL_DEBUG_MSG( 3, ( "client hello, compress alg.: %d", SSL_COMPRESS_NULL ) );
*p++ = 1;
*p++ = SSL_COMPRESS_NULL;
#endif
if ( ssl->hostname != NULL )
{
SSL_DEBUG_MSG( 3, ( "client hello, prepping for server name extension: %s",
ssl->hostname ) );
ext_len += ssl->hostname_len + 9;
}
if( ssl->renegotiation == SSL_RENEGOTIATION )
{
SSL_DEBUG_MSG( 3, ( "client hello, prepping for renegotiation extension" ) );
ext_len += 5 + ssl->verify_data_len;
}
/*
* Prepare signature_algorithms extension (TLS 1.2)
*/
if( ssl->max_minor_ver == SSL_MINOR_VERSION_3 )
{
#if defined(POLARSSL_SHA4_C)
sig_alg_list[sig_alg_len++] = SSL_HASH_SHA512;
sig_alg_list[sig_alg_len++] = SSL_SIG_RSA;
sig_alg_list[sig_alg_len++] = SSL_HASH_SHA384;
sig_alg_list[sig_alg_len++] = SSL_SIG_RSA;
#endif
#if defined(POLARSSL_SHA2_C)
sig_alg_list[sig_alg_len++] = SSL_HASH_SHA256;
sig_alg_list[sig_alg_len++] = SSL_SIG_RSA;
sig_alg_list[sig_alg_len++] = SSL_HASH_SHA224;
sig_alg_list[sig_alg_len++] = SSL_SIG_RSA;
#endif
#if defined(POLARSSL_SHA1_C)
sig_alg_list[sig_alg_len++] = SSL_HASH_SHA1;
sig_alg_list[sig_alg_len++] = SSL_SIG_RSA;
#endif
#if defined(POLARSSL_MD5_C)
sig_alg_list[sig_alg_len++] = SSL_HASH_MD5;
sig_alg_list[sig_alg_len++] = SSL_SIG_RSA;
#endif
ext_len += 6 + sig_alg_len;
}
SSL_DEBUG_MSG( 3, ( "client hello, total extension length: %d",
ext_len ) );
*p++ = (unsigned char)( ( ext_len >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( ext_len ) & 0xFF );
if ( ssl->hostname != NULL )
{
/*
* struct {
* NameType name_type;
* select (name_type) {
* case host_name: HostName;
* } name;
* } ServerName;
*
* enum {
* host_name(0), (255)
* } NameType;
*
* opaque HostName<1..2^16-1>;
*
* struct {
* ServerName server_name_list<1..2^16-1>
* } ServerNameList;
*/
SSL_DEBUG_MSG( 3, ( "client hello, adding server name extension: %s",
ssl->hostname ) );
*p++ = (unsigned char)( ( TLS_EXT_SERVERNAME >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( TLS_EXT_SERVERNAME ) & 0xFF );
*p++ = (unsigned char)( ( (ssl->hostname_len + 5) >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( (ssl->hostname_len + 5) ) & 0xFF );
*p++ = (unsigned char)( ( (ssl->hostname_len + 3) >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( (ssl->hostname_len + 3) ) & 0xFF );
*p++ = (unsigned char)( ( TLS_EXT_SERVERNAME_HOSTNAME ) & 0xFF );
*p++ = (unsigned char)( ( ssl->hostname_len >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( ssl->hostname_len ) & 0xFF );
memcpy( p, ssl->hostname, ssl->hostname_len );
p += ssl->hostname_len;
}
if( ssl->renegotiation == SSL_RENEGOTIATION )
{
/*
* Secure renegotiation
*/
SSL_DEBUG_MSG( 3, ( "client hello, renegotiation info 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 + 1 ) & 0xFF;
*p++ = ssl->verify_data_len & 0xFF;
memcpy( p, ssl->own_verify_data, ssl->verify_data_len );
p += ssl->verify_data_len;
}
if( ssl->max_minor_ver == SSL_MINOR_VERSION_3 )
{
/*
* enum {
* none(0), md5(1), sha1(2), sha224(3), sha256(4), sha384(5),
* sha512(6), (255)
* } HashAlgorithm;
*
* enum { anonymous(0), rsa(1), dsa(2), ecdsa(3), (255) }
* SignatureAlgorithm;
*
* struct {
* HashAlgorithm hash;
* SignatureAlgorithm signature;
* } SignatureAndHashAlgorithm;
*
* SignatureAndHashAlgorithm
* supported_signature_algorithms<2..2^16-2>;
*/
SSL_DEBUG_MSG( 3, ( "client hello, adding signature_algorithms extension" ) );
*p++ = (unsigned char)( ( TLS_EXT_SIG_ALG >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( TLS_EXT_SIG_ALG ) & 0xFF );
*p++ = (unsigned char)( ( ( sig_alg_len + 2 ) >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( ( sig_alg_len + 2 ) ) & 0xFF );
*p++ = (unsigned char)( ( sig_alg_len >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( sig_alg_len ) & 0xFF );
memcpy( p, sig_alg_list, sig_alg_len );
p += sig_alg_len;
}
ssl->out_msglen = p - buf;
ssl->out_msgtype = SSL_MSG_HANDSHAKE;
ssl->out_msg[0] = SSL_HS_CLIENT_HELLO;
ssl->state++;
if( ( ret = ssl_write_record( ssl ) ) != 0 )
{
SSL_DEBUG_RET( 1, "ssl_write_record", ret );
return( ret );
}
SSL_DEBUG_MSG( 2, ( "<= write client hello" ) );
return( 0 );
}
static int ssl_parse_renegotiation_info( ssl_context *ssl,
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_SERVER_HELLO );
}
ssl->secure_renegotiation = SSL_SECURE_RENEGOTIATION;
}
else
{
/* Check verify-data in constant-time. The length OTOH is no secret */
if( len != 1 + ssl->verify_data_len * 2 ||
buf[0] != ssl->verify_data_len * 2 ||
safer_memcmp( buf + 1,
ssl->own_verify_data, ssl->verify_data_len ) != 0 ||
safer_memcmp( buf + 1 + ssl->verify_data_len,
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_SERVER_HELLO );
}
}
return( 0 );
}
static int ssl_parse_server_hello( ssl_context *ssl )
{
#if defined(POLARSSL_DEBUG_C)
time_t t;
#endif
int ret, i, comp;
size_t n;
size_t ext_len = 0;
unsigned char *buf, *ext;
int renegotiation_info_seen = 0;
int handshake_failure = 0;
SSL_DEBUG_MSG( 2, ( "=> parse server hello" ) );
/*
* 0 . 0 handshake type
* 1 . 3 handshake length
* 4 . 5 protocol version
* 6 . 9 UNIX time()
* 10 . 37 random bytes
*/
buf = ssl->in_msg;
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 server hello message" ) );
return( POLARSSL_ERR_SSL_UNEXPECTED_MESSAGE );
}
SSL_DEBUG_MSG( 3, ( "server hello, chosen version: [%d:%d]",
buf[4], buf[5] ) );
if( ssl->in_hslen < 42 ||
buf[0] != SSL_HS_SERVER_HELLO ||
buf[4] != SSL_MAJOR_VERSION_3 )
{
SSL_DEBUG_MSG( 1, ( "bad server hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_SERVER_HELLO );
}
if( buf[5] > ssl->max_minor_ver )
{
SSL_DEBUG_MSG( 1, ( "bad server hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_SERVER_HELLO );
}
ssl->minor_ver = buf[5];
if( ssl->minor_ver < ssl->min_minor_ver )
{
SSL_DEBUG_MSG( 1, ( "server only supports ssl smaller than minimum"
" [%d:%d] < [%d:%d]", ssl->major_ver, ssl->minor_ver,
buf[4], buf[5] ) );
ssl_send_alert_message( ssl, SSL_ALERT_LEVEL_FATAL,
SSL_ALERT_MSG_PROTOCOL_VERSION );
return( POLARSSL_ERR_SSL_BAD_HS_PROTOCOL_VERSION );
}
#if defined(POLARSSL_DEBUG_C)
t = ( (time_t) buf[6] << 24 )
| ( (time_t) buf[7] << 16 )
| ( (time_t) buf[8] << 8 )
| ( (time_t) buf[9] );
#endif
memcpy( ssl->handshake->randbytes + 32, buf + 6, 32 );
n = buf[38];
SSL_DEBUG_MSG( 3, ( "server hello, current time: %lu", t ) );
SSL_DEBUG_BUF( 3, "server hello, random bytes", buf + 6, 32 );
if( n > 32 )
{
SSL_DEBUG_MSG( 1, ( "bad server hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_SERVER_HELLO );
}
/*
* 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 . 44+n+m extensions
*/
if( ssl->in_hslen > 42 + n )
{
ext_len = ( ( buf[42 + n] << 8 )
| ( buf[43 + n] ) );
if( ( ext_len > 0 && ext_len < 4 ) ||
ssl->in_hslen != 44 + n + ext_len )
{
SSL_DEBUG_MSG( 1, ( "bad server hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_SERVER_HELLO );
}
}
i = ( buf[39 + n] << 8 ) | buf[40 + n];
comp = buf[41 + n];
/*
* Initialize update checksum functions
*/
ssl_optimize_checksum( ssl, i );
SSL_DEBUG_MSG( 3, ( "server hello, session id len.: %d", n ) );
SSL_DEBUG_BUF( 3, "server hello, session id", buf + 39, n );
/*
* Check if the session can be resumed
*/
if( ssl->renegotiation != SSL_INITIAL_HANDSHAKE ||
ssl->handshake->resume == 0 || n == 0 ||
ssl->session_negotiate->ciphersuite != i ||
ssl->session_negotiate->compression != comp ||
ssl->session_negotiate->length != n ||
memcmp( ssl->session_negotiate->id, buf + 39, n ) != 0 )
{
ssl->state++;
ssl->handshake->resume = 0;
ssl->session_negotiate->start = time( NULL );
ssl->session_negotiate->ciphersuite = i;
ssl->session_negotiate->compression = comp;
ssl->session_negotiate->length = n;
memcpy( ssl->session_negotiate->id, buf + 39, n );
}
else
{
ssl->state = SSL_SERVER_CHANGE_CIPHER_SPEC;
if( ( ret = ssl_derive_keys( ssl ) ) != 0 )
{
SSL_DEBUG_RET( 1, "ssl_derive_keys", ret );
return( ret );
}
}
SSL_DEBUG_MSG( 3, ( "%s session has been resumed",
ssl->handshake->resume ? "a" : "no" ) );
SSL_DEBUG_MSG( 3, ( "server hello, chosen ciphersuite: %d", i ) );
SSL_DEBUG_MSG( 3, ( "server hello, compress alg.: %d", buf[41 + n] ) );
i = 0;
while( 1 )
{
if( ssl->ciphersuites[ssl->minor_ver][i] == 0 )
{
SSL_DEBUG_MSG( 1, ( "bad server hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_SERVER_HELLO );
}
if( ssl->ciphersuites[ssl->minor_ver][i++] == ssl->session_negotiate->ciphersuite )
break;
}
if( comp != SSL_COMPRESS_NULL
#if defined(POLARSSL_ZLIB_SUPPORT)
&& comp != SSL_COMPRESS_DEFLATE
#endif
)
{
SSL_DEBUG_MSG( 1, ( "bad server hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_SERVER_HELLO );
}
ssl->session_negotiate->compression = comp;
ext = buf + 44 + n;
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 server hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_SERVER_HELLO );
}
switch( ext_id )
{
case TLS_EXT_RENEGOTIATION_INFO:
SSL_DEBUG_MSG( 3, ( "found renegotiation extension" ) );
renegotiation_info_seen = 1;
if( ( ret = ssl_parse_renegotiation_info( ssl, ext + 4, ext_size ) ) != 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 server hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_SERVER_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_SERVER_HELLO );
}
SSL_DEBUG_MSG( 2, ( "<= parse server hello" ) );
return( 0 );
}
static int ssl_parse_server_key_exchange( ssl_context *ssl )
{
#if defined(POLARSSL_DHM_C)
int ret;
size_t n;
unsigned char *p, *end;
unsigned char hash[64];
md5_context md5;
sha1_context sha1;
int hash_id = SIG_RSA_RAW;
unsigned int hashlen = 0;
#endif
SSL_DEBUG_MSG( 2, ( "=> parse 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 parse server key exchange" ) );
ssl->state++;
return( 0 );
}
#if !defined(POLARSSL_DHM_C)
SSL_DEBUG_MSG( 1, ( "support for dhm in not available" ) );
return( POLARSSL_ERR_SSL_FEATURE_UNAVAILABLE );
#else
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 server key exchange message" ) );
return( POLARSSL_ERR_SSL_UNEXPECTED_MESSAGE );
}
if( ssl->in_msg[0] != SSL_HS_SERVER_KEY_EXCHANGE )
{
SSL_DEBUG_MSG( 1, ( "bad server key exchange message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE );
}
SSL_DEBUG_BUF( 3, "server key exchange", ssl->in_msg + 4, ssl->in_hslen - 4 );
/*
* 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;
*/
p = ssl->in_msg + 4;
end = ssl->in_msg + ssl->in_hslen;
if( ( ret = dhm_read_params( &ssl->handshake->dhm_ctx, &p, end ) ) != 0 )
{
SSL_DEBUG_MSG( 2, ( "DHM Read Params returned -0x%x", -ret ) );
SSL_DEBUG_MSG( 1, ( "bad server key exchange message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE );
}
if( ssl->minor_ver == SSL_MINOR_VERSION_3 )
{
if( p[1] != SSL_SIG_RSA )
{
SSL_DEBUG_MSG( 2, ( "server used unsupported SignatureAlgorithm %d", p[1] ) );
SSL_DEBUG_MSG( 1, ( "bad server key exchange message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE );
}
switch( p[0] )
{
#if defined(POLARSSL_MD5_C)
case SSL_HASH_MD5:
hash_id = SIG_RSA_MD5;
break;
#endif
#if defined(POLARSSL_SHA1_C)
case SSL_HASH_SHA1:
hash_id = SIG_RSA_SHA1;
break;
#endif
#if defined(POLARSSL_SHA2_C)
case SSL_HASH_SHA224:
hash_id = SIG_RSA_SHA224;
break;
case SSL_HASH_SHA256:
hash_id = SIG_RSA_SHA256;
break;
#endif
#if defined(POLARSSL_SHA4_C)
case SSL_HASH_SHA384:
hash_id = SIG_RSA_SHA384;
break;
case SSL_HASH_SHA512:
hash_id = SIG_RSA_SHA512;
break;
#endif
default:
SSL_DEBUG_MSG( 2, ( "Server used unsupported HashAlgorithm %d", p[0] ) );
SSL_DEBUG_MSG( 1, ( "bad server key exchange message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE );
}
SSL_DEBUG_MSG( 2, ( "Server used SignatureAlgorithm %d", p[1] ) );
SSL_DEBUG_MSG( 2, ( "Server used HashAlgorithm %d", p[0] ) );
p += 2;
}
n = ( p[0] << 8 ) | p[1];
p += 2;
if( end != p + n )
{
SSL_DEBUG_MSG( 1, ( "bad server key exchange message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE );
}
if( (unsigned int)( end - p ) !=
ssl->session_negotiate->peer_cert->rsa.len )
{
SSL_DEBUG_MSG( 1, ( "bad server key exchange message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE );
}
if( ssl->handshake->dhm_ctx.len < 64 || ssl->handshake->dhm_ctx.len > 512 )
{
SSL_DEBUG_MSG( 1, ( "bad server key exchange message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE );
}
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: GY", &ssl->handshake->dhm_ctx.GY );
if( ssl->minor_ver != SSL_MINOR_VERSION_3 )
{
/*
* 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);
*/
n = ssl->in_hslen - ( end - p ) - 6;
md5_starts( &md5 );
md5_update( &md5, ssl->handshake->randbytes, 64 );
md5_update( &md5, ssl->in_msg + 4, n );
md5_finish( &md5, hash );
sha1_starts( &sha1 );
sha1_update( &sha1, ssl->handshake->randbytes, 64 );
sha1_update( &sha1, ssl->in_msg + 4, n );
sha1_finish( &sha1, hash + 16 );
hash_id = SIG_RSA_RAW;
hashlen = 36;
}
else
{
sha2_context sha2;
#if defined(POLARSSL_SHA4_C)
sha4_context sha4;
#endif
n = ssl->in_hslen - ( end - p ) - 8;
/*
* digitally-signed struct {
* opaque client_random[32];
* opaque server_random[32];
* ServerDHParams params;
* };
*/
switch( hash_id )
{
#if defined(POLARSSL_MD5_C)
case SIG_RSA_MD5:
md5_starts( &md5 );
md5_update( &md5, ssl->handshake->randbytes, 64 );
md5_update( &md5, ssl->in_msg + 4, n );
md5_finish( &md5, hash );
hashlen = 16;
break;
#endif
#if defined(POLARSSL_SHA1_C)
case SIG_RSA_SHA1:
sha1_starts( &sha1 );
sha1_update( &sha1, ssl->handshake->randbytes, 64 );
sha1_update( &sha1, ssl->in_msg + 4, n );
sha1_finish( &sha1, hash );
hashlen = 20;
break;
#endif
#if defined(POLARSSL_SHA2_C)
case SIG_RSA_SHA224:
sha2_starts( &sha2, 1 );
sha2_update( &sha2, ssl->handshake->randbytes, 64 );
sha2_update( &sha2, ssl->in_msg + 4, n );
sha2_finish( &sha2, hash );
hashlen = 28;
break;
case SIG_RSA_SHA256:
sha2_starts( &sha2, 0 );
sha2_update( &sha2, ssl->handshake->randbytes, 64 );
sha2_update( &sha2, ssl->in_msg + 4, n );
sha2_finish( &sha2, hash );
hashlen = 32;
break;
#endif
#if defined(POLARSSL_SHA4_C)
case SIG_RSA_SHA384:
sha4_starts( &sha4, 1 );
sha4_update( &sha4, ssl->handshake->randbytes, 64 );
sha4_update( &sha4, ssl->in_msg + 4, n );
sha4_finish( &sha4, hash );
hashlen = 48;
break;
case SIG_RSA_SHA512:
sha4_starts( &sha4, 0 );
sha4_update( &sha4, ssl->handshake->randbytes, 64 );
sha4_update( &sha4, ssl->in_msg + 4, n );
sha4_finish( &sha4, hash );
hashlen = 64;
break;
#endif
}
}
SSL_DEBUG_BUF( 3, "parameters hash", hash, hashlen );
if( ( ret = rsa_pkcs1_verify( &ssl->session_negotiate->peer_cert->rsa,
NULL, NULL, RSA_PUBLIC,
hash_id, hashlen, hash, p ) ) != 0 )
{
SSL_DEBUG_RET( 1, "rsa_pkcs1_verify", ret );
return( ret );
}
ssl->state++;
SSL_DEBUG_MSG( 2, ( "<= parse server key exchange" ) );
return( 0 );
#endif
}
static int ssl_parse_certificate_request( ssl_context *ssl )
{
int ret;
unsigned char *buf, *p;
size_t n = 0, m = 0;
size_t cert_type_len = 0, sig_alg_len = 0, dn_len = 0;
SSL_DEBUG_MSG( 2, ( "=> parse certificate request" ) );
/*
* 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.
*/
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 certificate request message" ) );
return( POLARSSL_ERR_SSL_UNEXPECTED_MESSAGE );
}
ssl->client_auth = 0;
ssl->state++;
if( ssl->in_msg[0] == SSL_HS_CERTIFICATE_REQUEST )
ssl->client_auth++;
SSL_DEBUG_MSG( 3, ( "got %s certificate request",
ssl->client_auth ? "a" : "no" ) );
if( ssl->client_auth == 0 )
goto exit;
// TODO: handshake_failure alert for an anonymous server to request
// client authentication
buf = ssl->in_msg;
// Retrieve cert types
//
cert_type_len = buf[4];
n = cert_type_len;
if( ssl->in_hslen < 6 + n )
{
SSL_DEBUG_MSG( 1, ( "bad certificate request message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CERTIFICATE_REQUEST );
}
p = buf + 5;
while( cert_type_len > 0 )
{
if( *p == SSL_CERT_TYPE_RSA_SIGN )
{
ssl->handshake->cert_type = SSL_CERT_TYPE_RSA_SIGN;
break;
}
cert_type_len--;
p++;
}
if( ssl->handshake->cert_type == 0 )
{
SSL_DEBUG_MSG( 1, ( "no known cert_type provided" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CERTIFICATE_REQUEST );
}
if( ssl->minor_ver == SSL_MINOR_VERSION_3 )
{
sig_alg_len = ( ( buf[5 + n] << 8 )
| ( buf[6 + n] ) );
p = buf + 7 + n;
m += 2;
n += sig_alg_len;
if( ssl->in_hslen < 6 + n )
{
SSL_DEBUG_MSG( 1, ( "bad certificate request message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CERTIFICATE_REQUEST );
}
}
dn_len = ( ( buf[5 + m + n] << 8 )
| ( buf[6 + m + n] ) );
n += dn_len;
if( ssl->in_hslen != 7 + m + n )
{
SSL_DEBUG_MSG( 1, ( "bad certificate request message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CERTIFICATE_REQUEST );
}
exit:
SSL_DEBUG_MSG( 2, ( "<= parse certificate request" ) );
return( 0 );
}
static int ssl_parse_server_hello_done( ssl_context *ssl )
{
int ret;
SSL_DEBUG_MSG( 2, ( "=> parse server hello done" ) );
if( ssl->client_auth != 0 )
{
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 server hello done message" ) );
return( POLARSSL_ERR_SSL_UNEXPECTED_MESSAGE );
}
}
if( ssl->in_hslen != 4 ||
ssl->in_msg[0] != SSL_HS_SERVER_HELLO_DONE )
{
SSL_DEBUG_MSG( 1, ( "bad server hello done message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_SERVER_HELLO_DONE );
}
ssl->state++;
SSL_DEBUG_MSG( 2, ( "<= parse server hello done" ) );
return( 0 );
}
static int ssl_write_client_key_exchange( ssl_context *ssl )
{
int ret;
size_t i, n;
SSL_DEBUG_MSG( 2, ( "=> write 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 in not available" ) );
return( POLARSSL_ERR_SSL_FEATURE_UNAVAILABLE );
#else
/*
* DHM key exchange -- send G^X mod P
*/
n = ssl->handshake->dhm_ctx.len;
ssl->out_msg[4] = (unsigned char)( n >> 8 );
ssl->out_msg[5] = (unsigned char)( n );
i = 6;
ret = dhm_make_public( &ssl->handshake->dhm_ctx,
(int) mpi_size( &ssl->handshake->dhm_ctx.P ),
&ssl->out_msg[i], n,
ssl->f_rng, ssl->p_rng );
if( ret != 0 )
{
SSL_DEBUG_RET( 1, "dhm_make_public", ret );
return( ret );
}
SSL_DEBUG_MPI( 3, "DHM: X ", &ssl->handshake->dhm_ctx.X );
SSL_DEBUG_MPI( 3, "DHM: GX", &ssl->handshake->dhm_ctx.GX );
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( ret );
}
SSL_DEBUG_MPI( 3, "DHM: K ", &ssl->handshake->dhm_ctx.K );
#endif
}
else
{
/*
* RSA key exchange -- send rsa_public(pkcs1 v1.5(premaster))
*/
ssl->handshake->premaster[0] = (unsigned char) ssl->max_major_ver;
ssl->handshake->premaster[1] = (unsigned char) ssl->max_minor_ver;
ssl->handshake->pmslen = 48;
ret = ssl->f_rng( ssl->p_rng, ssl->handshake->premaster + 2,
ssl->handshake->pmslen - 2 );
if( ret != 0 )
return( ret );
i = 4;
n = ssl->session_negotiate->peer_cert->rsa.len;
if( ssl->minor_ver != SSL_MINOR_VERSION_0 )
{
i += 2;
ssl->out_msg[4] = (unsigned char)( n >> 8 );
ssl->out_msg[5] = (unsigned char)( n );
}
ret = rsa_pkcs1_encrypt( &ssl->session_negotiate->peer_cert->rsa,
ssl->f_rng, ssl->p_rng,
RSA_PUBLIC,
ssl->handshake->pmslen,
ssl->handshake->premaster,
ssl->out_msg + i );
if( ret != 0 )
{
SSL_DEBUG_RET( 1, "rsa_pkcs1_encrypt", ret );
return( ret );
}
}
if( ( ret = ssl_derive_keys( ssl ) ) != 0 )
{
SSL_DEBUG_RET( 1, "ssl_derive_keys", ret );
return( ret );
}
ssl->out_msglen = i + n;
ssl->out_msgtype = SSL_MSG_HANDSHAKE;
ssl->out_msg[0] = SSL_HS_CLIENT_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 client key exchange" ) );
return( 0 );
}
static int ssl_write_certificate_verify( ssl_context *ssl )
{
int ret = 0;
size_t n = 0, offset = 0;
unsigned char hash[48];
int hash_id = SIG_RSA_RAW;
unsigned int hashlen = 36;
SSL_DEBUG_MSG( 2, ( "=> write certificate verify" ) );
if( ssl->client_auth == 0 || ssl->own_cert == NULL )
{
SSL_DEBUG_MSG( 2, ( "<= skip write certificate verify" ) );
ssl->state++;
return( 0 );
}
if( ssl->rsa_key == NULL )
{
SSL_DEBUG_MSG( 1, ( "got no private key" ) );
return( POLARSSL_ERR_SSL_PRIVATE_KEY_REQUIRED );
}
/*
* Make an RSA signature of the handshake digests
*/
ssl->handshake->calc_verify( ssl, hash );
if( ssl->minor_ver != SSL_MINOR_VERSION_3 )
{
/*
* digitally-signed struct {
* opaque md5_hash[16];
* opaque sha_hash[20];
* };
*
* md5_hash
* MD5(handshake_messages);
*
* sha_hash
* SHA(handshake_messages);
*/
hashlen = 36;
hash_id = SIG_RSA_RAW;
}
else
{
/*
* digitally-signed struct {
* opaque handshake_messages[handshake_messages_length];
* };
*
* Taking shortcut here. We assume that the server always allows the
* PRF Hash function and has sent it in the allowed signature
* algorithms list received in the Certificate Request message.
*
* Until we encounter a server that does not, we will take this
* shortcut.
*
* Reason: Otherwise we should have running hashes for SHA512 and SHA224
* in order to satisfy 'weird' needs from the server side.
*/
if( ssl->session_negotiate->ciphersuite == TLS_RSA_WITH_AES_256_GCM_SHA384 ||
ssl->session_negotiate->ciphersuite == TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 )
{
hash_id = SIG_RSA_SHA384;
hashlen = 48;
ssl->out_msg[4] = SSL_HASH_SHA384;
ssl->out_msg[5] = SSL_SIG_RSA;
}
else
{
hash_id = SIG_RSA_SHA256;
hashlen = 32;
ssl->out_msg[4] = SSL_HASH_SHA256;
ssl->out_msg[5] = SSL_SIG_RSA;
}
offset = 2;
}
if ( ssl->rsa_key )
n = ssl->rsa_key_len ( ssl->rsa_key );
ssl->out_msg[4 + offset] = (unsigned char)( n >> 8 );
ssl->out_msg[5 + offset] = (unsigned char)( n );
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 + offset );
}
if (ret != 0)
{
SSL_DEBUG_RET( 1, "pkcs1_sign", ret );
return( ret );
}
ssl->out_msglen = 6 + n + offset;
ssl->out_msgtype = SSL_MSG_HANDSHAKE;
ssl->out_msg[0] = SSL_HS_CERTIFICATE_VERIFY;
ssl->state++;
if( ( ret = ssl_write_record( ssl ) ) != 0 )
{
SSL_DEBUG_RET( 1, "ssl_write_record", ret );
return( ret );
}
SSL_DEBUG_MSG( 2, ( "<= write certificate verify" ) );
return( 0 );
}
/*
* SSL handshake -- client side -- single step
*/
int ssl_handshake_client_step( ssl_context *ssl )
{
int ret = 0;
if( ssl->state == SSL_HANDSHAKE_OVER )
return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );
SSL_DEBUG_MSG( 2, ( "client 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_write_client_hello( ssl );
break;
/*
* <== ServerHello
* Certificate
* ( ServerKeyExchange )
* ( CertificateRequest )
* ServerHelloDone
*/
case SSL_SERVER_HELLO:
ret = ssl_parse_server_hello( ssl );
break;
case SSL_SERVER_CERTIFICATE:
ret = ssl_parse_certificate( ssl );
break;
case SSL_SERVER_KEY_EXCHANGE:
ret = ssl_parse_server_key_exchange( ssl );
break;
case SSL_CERTIFICATE_REQUEST:
ret = ssl_parse_certificate_request( ssl );
break;
case SSL_SERVER_HELLO_DONE:
ret = ssl_parse_server_hello_done( ssl );
break;
/*
* ==> ( Certificate/Alert )
* ClientKeyExchange
* ( CertificateVerify )
* ChangeCipherSpec
* Finished
*/
case SSL_CLIENT_CERTIFICATE:
ret = ssl_write_certificate( ssl );
break;
case SSL_CLIENT_KEY_EXCHANGE:
ret = ssl_write_client_key_exchange( ssl );
break;
case SSL_CERTIFICATE_VERIFY:
ret = ssl_write_certificate_verify( ssl );
break;
case SSL_CLIENT_CHANGE_CIPHER_SPEC:
ret = ssl_write_change_cipher_spec( ssl );
break;
case SSL_CLIENT_FINISHED:
ret = ssl_write_finished( ssl );
break;
/*
* <== ChangeCipherSpec
* Finished
*/
case SSL_SERVER_CHANGE_CIPHER_SPEC:
ret = ssl_parse_change_cipher_spec( ssl );
break;
case SSL_SERVER_FINISHED:
ret = ssl_parse_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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