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Refine encrypted extensions parse function

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Change arguments of API.
Send different messages base on extensions types.

Signed-off-by: XiaokangQian <xiaokang.qian@arm.com>
This commit is contained in:
XiaokangQian 2021-10-09 10:12:11 +00:00
parent 140f0459ed
commit 08da26c58f
1 changed files with 47 additions and 36 deletions
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83
library/ssl_tls13_client.c
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@ -1411,8 +1411,8 @@ cleanup:
static int ssl_tls1_3_process_encrypted_extensions( mbedtls_ssl_context *ssl ); static int ssl_tls1_3_process_encrypted_extensions( mbedtls_ssl_context *ssl );
static int ssl_tls1_3_parse_encrypted_extensions( mbedtls_ssl_context *ssl, static int ssl_tls1_3_parse_encrypted_extensions( mbedtls_ssl_context *ssl,
const unsigned char *buf, const unsigned char *buf,
size_t buf_len ); const unsigned char *end );
static int ssl_tls1_3_postprocess_encrypted_extensions( mbedtls_ssl_context *ssl ); static int ssl_tls1_3_postprocess_encrypted_extensions( mbedtls_ssl_context *ssl );
/* /*
@ -1431,7 +1431,7 @@ static int ssl_tls1_3_process_encrypted_extensions( mbedtls_ssl_context *ssl )
&buf, &buf_len ) ); &buf, &buf_len ) );
/* Process the message contents */ /* Process the message contents */
MBEDTLS_SSL_PROC_CHK( ssl_tls1_3_parse_encrypted_extensions( ssl, buf, buf_len ) ); MBEDTLS_SSL_PROC_CHK( ssl_tls1_3_parse_encrypted_extensions( ssl, buf, ( buf + buf_len ) ) );
mbedtls_ssl_tls1_3_add_hs_msg_to_checksum( mbedtls_ssl_tls1_3_add_hs_msg_to_checksum(
ssl, MBEDTLS_SSL_HS_ENCRYPTED_EXTENSION, buf, buf_len ); ssl, MBEDTLS_SSL_HS_ENCRYPTED_EXTENSION, buf, buf_len );
@ -1445,32 +1445,27 @@ cleanup:
} }
/* Parse EncryptedExtensions message
* struct {
* Extension extensions<0..2^16-1>;
* } EncryptedExtensions;
*/
static int ssl_tls1_3_parse_encrypted_extensions( mbedtls_ssl_context *ssl, static int ssl_tls1_3_parse_encrypted_extensions( mbedtls_ssl_context *ssl,
const unsigned char *buf, const unsigned char *buf,
size_t buf_len ) const unsigned char *end )
{ {
int ret = 0; int ret = 0;
size_t p_ext_len; size_t extensions_len;
const unsigned char *end = buf + buf_len;
const unsigned char *p = buf; const unsigned char *p = buf;
MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, 2); MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, 2 );
p_ext_len = MBEDTLS_GET_UINT16_BE(buf, 0); extensions_len = MBEDTLS_GET_UINT16_BE(p, 0);
p += 2; /* skip extension length */ p += 2;
/* Checking for an extension length that is too short */
if( p_ext_len > 0 && p_ext_len < 4 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "EncryptedExtension message too short" ) );
MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR, \
MBEDTLS_ERR_SSL_DECODE_ERROR );
return( MBEDTLS_ERR_SSL_DECODE_ERROR );
}
/* Checking for an extension length that isn't aligned with the rest /* Checking for an extension length that isn't aligned with the rest
* of the message */ * of the message */
if( buf_len != 2 + p_ext_len ) if( p + extensions_len != end )
{ {
MBEDTLS_SSL_DEBUG_MSG( 1, ( "EncryptedExtension lengths misaligned" ) ); MBEDTLS_SSL_DEBUG_MSG( 1, ( "EncryptedExtension lengths misaligned" ) );
MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR, \ MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR, \
@ -1478,31 +1473,47 @@ static int ssl_tls1_3_parse_encrypted_extensions( mbedtls_ssl_context *ssl,
return( MBEDTLS_ERR_SSL_DECODE_ERROR ); return( MBEDTLS_ERR_SSL_DECODE_ERROR );
} }
MBEDTLS_SSL_DEBUG_BUF( 3, "encrypted extensions extensions", p, p_ext_len ); MBEDTLS_SSL_DEBUG_BUF( 3, "encrypted extensions extensions", p, extensions_len );
while( p_ext_len ) while( p < end )
{ {
unsigned int ext_id = MBEDTLS_GET_UINT16_BE(p, 0); unsigned int extension_type;
size_t ext_size = MBEDTLS_GET_UINT16_BE(p, 2); size_t extension_data_len;
if( ext_size + 4 > p_ext_len ) /*
{ * struct {
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad encrypted extensions message" ) ); * ExtensionType extension_type; (2 bytes)
MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR, \ * opaque extension_data<0..2^16-1>;
MBEDTLS_ERR_SSL_DECODE_ERROR ); * } Extension;
return( MBEDTLS_ERR_SSL_DECODE_ERROR ); */
} MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, 4 );
extension_type = MBEDTLS_GET_UINT16_BE( p, 0 );
extension_data_len = MBEDTLS_GET_UINT16_BE( p, 2 );
p += 4;
MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, extension_data_len );
/* TBD: The client MUST check EncryptedExtensions for the /* TBD: The client MUST check EncryptedExtensions for the
* presence of any forbidden extensions and if any are found MUST abort * presence of any forbidden extensions and if any are found MUST abort
* the handshake with an "illegal_parameter" alert. * the handshake with an "unsupported_extension" alert.
*/ */
((void) ext_id); switch( extension_type )
{
p_ext_len -= 4 + ext_size; case MBEDTLS_TLS_EXT_SUPPORTED_GROUPS:
p += 4 + ext_size; MBEDTLS_SSL_DEBUG_MSG( 3, ( "found extensions supported groups" ) );
break;
if( p_ext_len > 0 && p_ext_len < 4 ) default:
MBEDTLS_SSL_DEBUG_MSG( 3, ( "unsupported extension found: %d ( ignoring )", extension_type) );
break;
}
extensions_len -= 4 + extension_data_len;
p += extension_data_len;
/* Checking for an extension length that is too short */
if( extensions_len > 0 && extensions_len < 4 )
{ {
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad encrypted extensions message" ) ); MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad encrypted extensions message" ) );
MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR, \ MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR, \