- Removed handling for SSLv2 Client Hello (as per RFC 5246 recommendation)

This commit is contained in:
Paul Bakker 2012-09-09 19:17:02 +00:00
parent 68b6d88f5e
commit ec636f3bdd
2 changed files with 155 additions and 282 deletions

View file

@ -35,6 +35,7 @@ Changes
to not match CN if subjectAltName extension is present (Closes ticket #56)
* Cipher layer cipher_mode_t POLARSSL_MODE_CFB128 is renamed to
POLARSSL_MODE_CFB, to also handle different block size CFB modes.
* Removed handling for SSLv2 Client Hello (as per RFC 5246 recommendation)
Bugfix
* Fixed handling error in mpi_cmp_mpi() on longer B values (found by

View file

@ -44,7 +44,7 @@ static int ssl_parse_client_hello( ssl_context *ssl )
unsigned int i, j;
size_t n;
unsigned int ciph_len, sess_len;
unsigned int chal_len, comp_len;
unsigned int comp_len;
unsigned char *buf, *p;
SSL_DEBUG_MSG( 2, ( "=> parse client hello" ) );
@ -57,297 +57,169 @@ static int ssl_parse_client_hello( ssl_context *ssl )
buf = ssl->in_hdr;
if( ( buf[0] & 0x80 ) != 0 )
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_BUF( 4, "record header", buf, 5 );
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
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] ) );
n = ( buf[3] << 8 ) | 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 )
if( n < 45 || n > 512 )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
if( ( ret = ssl_fetch_input( ssl, 5 + n ) ) != 0 )
{
SSL_DEBUG_RET( 1, "ssl_fetch_input", ret );
return( ret );
}
buf = ssl->in_msg;
n = ssl->in_left - 5;
ssl->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;
ssl->max_major_ver = buf[4];
ssl->max_minor_ver = buf[5];
memcpy( ssl->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->length = sess_len;
memset( ssl->session->id, 0, sizeof( ssl->session->id ) );
memcpy( ssl->session->id, buf + 39 , ssl->session->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 );
}
ssl->session->compression = SSL_COMPRESS_NULL;
#if defined(POLARSSL_ZLIB_SUPPORT)
for( i = 0; i < comp_len; ++i )
{
if( buf[41 + sess_len + ciph_len + i] == SSL_COMPRESS_DEFLATE )
{
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->max_major_ver = buf[3];
ssl->max_minor_ver = buf[4];
ssl->major_ver = SSL_MAJOR_VERSION_3;
ssl->minor_ver = ( buf[4] <= SSL_MINOR_VERSION_3 )
? buf[4] : SSL_MINOR_VERSION_3;
if( ( ret = ssl_fetch_input( ssl, 2 + n ) ) != 0 )
{
SSL_DEBUG_RET( 1, "ssl_fetch_input", ret );
return( ret );
}
ssl->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->length = sess_len;
memset( ssl->session->id, 0, sizeof( ssl->session->id ) );
memcpy( ssl->session->id, p, ssl->session->length );
p += sess_len;
memset( ssl->randbytes, 0, 64 );
memcpy( ssl->randbytes + 32 - chal_len, p, chal_len );
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;
}
ssl->session->compression = SSL_COMPRESS_DEFLATE;
break;
}
}
else
{
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( ( ret = ssl_fetch_input( ssl, 5 + n ) ) != 0 )
{
SSL_DEBUG_RET( 1, "ssl_fetch_input", ret );
return( ret );
}
buf = ssl->in_msg;
n = ssl->in_left - 5;
ssl->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;
ssl->max_major_ver = buf[4];
ssl->max_minor_ver = buf[5];
memcpy( ssl->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->length = sess_len;
memset( ssl->session->id, 0, sizeof( ssl->session->id ) );
memcpy( ssl->session->id, buf + 39 , ssl->session->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 );
}
ssl->session->compression = SSL_COMPRESS_NULL;
#if defined(POLARSSL_ZLIB_SUPPORT)
for( i = 0; i < comp_len; ++i )
{
if( buf[41 + sess_len + ciph_len + i] == SSL_COMPRESS_DEFLATE )
{
ssl->session->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 );
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 );
/*
* Search for a matching ciphersuite
*/
for( i = 0; ssl->ciphersuites[i] != 0; i++ )
/*
* 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 )
{
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;
}
if( p[0] == 0 && p[1] == ssl->ciphersuites[i] )
goto have_ciphersuite;
}
}