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Add parameter to ssl_read_record() controlling checksum update

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Previously, mbedtls_ssl_read_record() always updated the handshake
checksum in case a handshake record was received. While desirable
most of the time, for the CertificateVerify message the checksum
update must only happen after the message has been fully processed,
because the validation requires the handshake digest up to but
excluding the CertificateVerify itself. As a remedy, the bulk
of mbedtls_ssl_read_record() was previously duplicated within
ssl_parse_certificate_verify(), hardening maintenance in case
mbedtls_ssl_read_record() is subject to changes.

This commit adds a boolean parameter to mbedtls_ssl_read_record()
indicating whether the checksum should be updated in case of a
handshake message or not. This allows using it also for
ssl_parse_certificate_verify(), manually updating the checksum
after the message has been processed.
This commit is contained in:
Hanno Becker 2018-08-15 13:56:18 +01:00
parent e1dcb03557
commit 327c93b182
4 changed files with 18 additions and 31 deletions
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2
include/mbedtls/ssl_internal.h
View file

@ -557,7 +557,7 @@ void mbedtls_ssl_update_handshake_status( mbedtls_ssl_context *ssl );
* following the above definition. * following the above definition.
* *
*/ */
int mbedtls_ssl_read_record( mbedtls_ssl_context *ssl ); int mbedtls_ssl_read_record( mbedtls_ssl_context *ssl, unsigned update_digest );
int mbedtls_ssl_fetch_input( mbedtls_ssl_context *ssl, size_t nb_want ); int mbedtls_ssl_fetch_input( mbedtls_ssl_context *ssl, size_t nb_want );
int mbedtls_ssl_write_handshake_msg( mbedtls_ssl_context *ssl ); int mbedtls_ssl_write_handshake_msg( mbedtls_ssl_context *ssl );

10
library/ssl_cli.c
View file

@ -1500,7 +1500,7 @@ static int ssl_parse_server_hello( mbedtls_ssl_context *ssl )
buf = ssl->in_msg; buf = ssl->in_msg;
if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 ) if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 )
{ {
/* No alert on a read error. */ /* No alert on a read error. */
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret ); MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret );
@ -2349,7 +2349,7 @@ static int ssl_parse_server_key_exchange( mbedtls_ssl_context *ssl )
#endif /* MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED || #endif /* MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED ||
MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED */ MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED */
if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 ) if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 )
{ {
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret ); MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret );
return( ret ); return( ret );
@ -2656,7 +2656,7 @@ static int ssl_parse_certificate_request( mbedtls_ssl_context *ssl )
return( 0 ); return( 0 );
} }
if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 ) if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 )
{ {
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret ); MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret );
return( ret ); return( ret );
@ -2808,7 +2808,7 @@ static int ssl_parse_server_hello_done( mbedtls_ssl_context *ssl )
MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse server hello done" ) ); MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse server hello done" ) );
if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 ) if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 )
{ {
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret ); MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret );
return( ret ); return( ret );
@ -3297,7 +3297,7 @@ static int ssl_parse_new_session_ticket( mbedtls_ssl_context *ssl )
MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse new session ticket" ) ); MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse new session ticket" ) );
if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 ) if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 )
{ {
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret ); MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret );
return( ret ); return( ret );

21
library/ssl_srv.c
View file

@ -3728,7 +3728,7 @@ static int ssl_parse_client_key_exchange( mbedtls_ssl_context *ssl )
} }
else else
#endif #endif
if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 ) if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 )
{ {
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret ); MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret );
return( ret ); return( ret );
@ -4038,25 +4038,10 @@ static int ssl_parse_certificate_verify( mbedtls_ssl_context *ssl )
} }
/* Read the message without adding it to the checksum */ /* Read the message without adding it to the checksum */
do { ret = mbedtls_ssl_read_record( ssl, 0 /* no checksum update */ );
do ret = mbedtls_ssl_read_record_layer( ssl );
while( ret == MBEDTLS_ERR_SSL_CONTINUE_PROCESSING );
if( ret != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, ( "mbedtls_ssl_read_record_layer" ), ret );
return( ret );
}
ret = mbedtls_ssl_handle_message_type( ssl );
} while( MBEDTLS_ERR_SSL_NON_FATAL == ret ||
MBEDTLS_ERR_SSL_CONTINUE_PROCESSING == ret );
if( 0 != ret ) if( 0 != ret )
{ {
MBEDTLS_SSL_DEBUG_RET( 1, ( "mbedtls_ssl_handle_message_type" ), ret ); MBEDTLS_SSL_DEBUG_RET( 1, ( "mbedtls_ssl_read_record" ), ret );
return( ret ); return( ret );
} }

16
library/ssl_tls.c
View file

@ -4283,7 +4283,8 @@ static void ssl_handshake_wrapup_free_hs_transform( mbedtls_ssl_context *ssl );
* RFC 6347 4.1.2.7) and continue reading until a valid record is found. * RFC 6347 4.1.2.7) and continue reading until a valid record is found.
* *
*/ */
int mbedtls_ssl_read_record( mbedtls_ssl_context *ssl ) int mbedtls_ssl_read_record( mbedtls_ssl_context *ssl,
unsigned update_digest )
{ {
int ret; int ret;
@ -4313,7 +4314,8 @@ int mbedtls_ssl_read_record( mbedtls_ssl_context *ssl )
return( ret ); return( ret );
} }
if( ssl->in_msgtype == MBEDTLS_SSL_MSG_HANDSHAKE ) if( ssl->in_msgtype == MBEDTLS_SSL_MSG_HANDSHAKE &&
update_digest == 1 )
{ {
mbedtls_ssl_update_handshake_status( ssl ); mbedtls_ssl_update_handshake_status( ssl );
} }
@ -4900,7 +4902,7 @@ int mbedtls_ssl_parse_certificate( mbedtls_ssl_context *ssl )
} }
#endif #endif
if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 ) if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 )
{ {
/* mbedtls_ssl_read_record may have sent an alert already. We /* mbedtls_ssl_read_record may have sent an alert already. We
let it decide whether to alert. */ let it decide whether to alert. */
@ -5275,7 +5277,7 @@ int mbedtls_ssl_parse_change_cipher_spec( mbedtls_ssl_context *ssl )
MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse change cipher spec" ) ); MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse change cipher spec" ) );
if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 ) if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 )
{ {
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret ); MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret );
return( ret ); return( ret );
@ -5904,7 +5906,7 @@ int mbedtls_ssl_parse_finished( mbedtls_ssl_context *ssl )
ssl->handshake->calc_finished( ssl, buf, ssl->conf->endpoint ^ 1 ); ssl->handshake->calc_finished( ssl, buf, ssl->conf->endpoint ^ 1 );
if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 ) if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 )
{ {
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret ); MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret );
return( ret ); return( ret );
@ -7653,7 +7655,7 @@ int mbedtls_ssl_read( mbedtls_ssl_context *ssl, unsigned char *buf, size_t len )
ssl_set_timer( ssl, ssl->conf->read_timeout ); ssl_set_timer( ssl, ssl->conf->read_timeout );
} }
if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 ) if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 )
{ {
if( ret == MBEDTLS_ERR_SSL_CONN_EOF ) if( ret == MBEDTLS_ERR_SSL_CONN_EOF )
return( 0 ); return( 0 );
@ -7668,7 +7670,7 @@ int mbedtls_ssl_read( mbedtls_ssl_context *ssl, unsigned char *buf, size_t len )
/* /*
* OpenSSL sends empty messages to randomize the IV * OpenSSL sends empty messages to randomize the IV
*/ */
if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 ) if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 )
{ {
if( ret == MBEDTLS_ERR_SSL_CONN_EOF ) if( ret == MBEDTLS_ERR_SSL_CONN_EOF )
return( 0 ); return( 0 );