Set pointer to start of plaintext at record decryption time
The SSL context structure mbedtls_ssl_context contains several pointers
ssl->in_hdr, ssl->in_len, ssl->in_iv, ssl->in_msg pointing to various
parts of the record header in an incoming record, and they are setup
in the static function ssl_update_in_pointers() based on the _expected_
transform for the next incoming record.
In particular, the pointer ssl->in_msg is set to where the record plaintext
should reside after record decryption, and an assertion double-checks this
after each call to ssl_decrypt_buf().
This commit removes the dependency of ssl_update_in_pointers() on the
expected incoming transform by setting ssl->in_msg to ssl->in_iv --
the beginning of the record content (potentially including the IV) --
and adjusting ssl->in_msg after calling ssl_decrypt_buf() on a protected
record.
Care has to be taken to not load ssl->in_msg before calling
mbedtls_ssl_read_record(), then, which was previously the
case in ssl_parse_server_hello(); the commit fixes that.
diff --git a/library/ssl_cli.c b/library/ssl_cli.c
index 45f4c40..228e335 100644
--- a/library/ssl_cli.c
+++ b/library/ssl_cli.c
@@ -1658,8 +1658,6 @@
MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse server hello" ) );
- buf = ssl->in_msg;
-
if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 )
{
/* No alert on a read error. */
@@ -1667,6 +1665,8 @@
return( ret );
}
+ buf = ssl->in_msg;
+
if( ssl->in_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE )
{
#if defined(MBEDTLS_SSL_RENEGOTIATION)