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Merge pull request #4937 from xkqian/add_tls13_encrypted_extension

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The rebase after the two approvals was simple enough to need only one reviewer.
This commit is contained in:
Ronald Cron
2021-10-28 09:34:56 +02:00
committed by GitHub
parent 4c9313fcd9 ab7f50d638
commit cf1f376b24
3 changed files with 134 additions and 9 deletions
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131
library/ssl_tls13_client.c
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@ -1395,11 +1395,134 @@ cleanup:
}
/*
* Handler for MBEDTLS_SSL_ENCRYPTED_EXTENSIONS
*
* EncryptedExtensions message
*
* The EncryptedExtensions message contains any extensions which
* should be protected, i.e., any which are not needed to establish
* the cryptographic context.
*/
static int ssl_tls1_3_process_encrypted_extensions( mbedtls_ssl_context *ssl )
/*
* Overview
*/
/* Main entry point; orchestrates the other functions */
static int ssl_tls13_process_encrypted_extensions( mbedtls_ssl_context *ssl );
static int ssl_tls13_parse_encrypted_extensions( mbedtls_ssl_context *ssl,
const unsigned char *buf,
const unsigned char *end );
static int ssl_tls13_postprocess_encrypted_extensions( mbedtls_ssl_context *ssl );
/*
* Handler for MBEDTLS_SSL_ENCRYPTED_EXTENSIONS
*/
static int ssl_tls13_process_encrypted_extensions( mbedtls_ssl_context *ssl )
{
int ret;
unsigned char *buf;
size_t buf_len;
MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse encrypted extensions" ) );
MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_tls1_3_fetch_handshake_msg( ssl,
MBEDTLS_SSL_HS_ENCRYPTED_EXTENSIONS,
&buf, &buf_len ) );
/* Process the message contents */
MBEDTLS_SSL_PROC_CHK(
ssl_tls13_parse_encrypted_extensions( ssl, buf, buf + buf_len ) );
mbedtls_ssl_tls1_3_add_hs_msg_to_checksum(
ssl, MBEDTLS_SSL_HS_ENCRYPTED_EXTENSIONS, buf, buf_len );
MBEDTLS_SSL_PROC_CHK( ssl_tls13_postprocess_encrypted_extensions( ssl ) );
cleanup:
MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse encrypted extensions" ) );
return( ret );
}
/* Parse EncryptedExtensions message
* struct {
* Extension extensions<0..2^16-1>;
* } EncryptedExtensions;
*/
static int ssl_tls13_parse_encrypted_extensions( mbedtls_ssl_context *ssl,
const unsigned char *buf,
const unsigned char *end )
{
int ret = 0;
size_t extensions_len;
const unsigned char *p = buf;
const unsigned char *extensions_end;
MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, 2 );
extensions_len = MBEDTLS_GET_UINT16_BE( p, 0 );
p += 2;
MBEDTLS_SSL_DEBUG_BUF( 3, "encrypted extensions", p, extensions_len );
extensions_end = p + extensions_len;
MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, extensions_len );
while( p < extensions_end )
{
unsigned int extension_type;
size_t extension_data_len;
/*
* struct {
* ExtensionType extension_type; (2 bytes)
* opaque extension_data<0..2^16-1>;
* } Extension;
*/
MBEDTLS_SSL_CHK_BUF_READ_PTR( p, extensions_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, extensions_end, extension_data_len );
/* The client MUST check EncryptedExtensions for the
* presence of any forbidden extensions and if any are found MUST abort
* the handshake with an "unsupported_extension" alert.
*/
switch( extension_type )
{
case MBEDTLS_TLS_EXT_SUPPORTED_GROUPS:
MBEDTLS_SSL_DEBUG_MSG( 3, ( "found extensions supported groups" ) );
break;
default:
MBEDTLS_SSL_DEBUG_MSG(
3, ( "unsupported extension found: %u ", extension_type) );
MBEDTLS_SSL_PEND_FATAL_ALERT(
MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_EXT, \
MBEDTLS_ERR_SSL_UNSUPPORTED_EXTENSION );
return ( MBEDTLS_ERR_SSL_UNSUPPORTED_EXTENSION );
}
p += extension_data_len;
}
/* Check that we consumed all the message. */
if( p != end )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "EncryptedExtension lengths misaligned" ) );
MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR, \
MBEDTLS_ERR_SSL_DECODE_ERROR );
return( MBEDTLS_ERR_SSL_DECODE_ERROR );
}
return( ret );
}
static int ssl_tls13_postprocess_encrypted_extensions( mbedtls_ssl_context *ssl )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "%s hasn't been implemented", __func__ ) );
mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_CERTIFICATE_REQUEST );
return( 0 );
}
@ -1516,7 +1639,7 @@ int mbedtls_ssl_tls13_handshake_client_step( mbedtls_ssl_context *ssl )
break;
case MBEDTLS_SSL_ENCRYPTED_EXTENSIONS:
ret = ssl_tls1_3_process_encrypted_extensions( ssl );
ret = ssl_tls13_process_encrypted_extensions( ssl );
break;
case MBEDTLS_SSL_CERTIFICATE_REQUEST: