Increment record sequence number in ssl_write_record()
Previously, the record sequence number was incremented at the
end of each successful call to mbedtls_ssl_flush_output(),
which works as long as there is precisely one such call for
each outgoing record.
When packing multiple records into a single datagram, this
property is no longer true, and instead the increment of the
record sequence number must happen after the record has been
prepared, and not after it has been dispatched.
This commit moves the code for incrementing the record sequence
number from mbedtls_ssl_flush_output() to ssl_write_record().
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index f2373eb..9342321 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -2648,7 +2648,7 @@
int mbedtls_ssl_flush_output( mbedtls_ssl_context *ssl )
{
int ret;
- unsigned char *buf, i;
+ unsigned char *buf;
MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> flush output" ) );
@@ -2691,16 +2691,6 @@
ssl->out_left -= ret;
}
- for( i = 8; i > ssl_ep_len( ssl ); i-- )
- if( ++ssl->out_ctr[i - 1] != 0 )
- break;
-
- /* The loop goes to its end iff the counter is wrapping */
- if( i == ssl_ep_len( ssl ) )
- {
- MBEDTLS_SSL_DEBUG_MSG( 1, ( "outgoing message counter would wrap" ) );
- return( MBEDTLS_ERR_SSL_COUNTER_WRAPPING );
- }
MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= flush output" ) );
@@ -3236,6 +3226,16 @@
MBEDTLS_SSL_DEBUG_BUF( 4, "output record sent to network",
ssl->out_hdr, mbedtls_ssl_hdr_len( ssl ) + ssl->out_msglen );
+ for( i = 8; i > ssl_ep_len( ssl ); i-- )
+ if( ++ssl->cur_out_ctr[i - 1] != 0 )
+ break;
+
+ /* The loop goes to its end iff the counter is wrapping */
+ if( i == ssl_ep_len( ssl ) )
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 1, ( "outgoing message counter would wrap" ) );
+ return( MBEDTLS_ERR_SSL_COUNTER_WRAPPING );
+ }
}
if( ( ret = mbedtls_ssl_flush_output( ssl ) ) != 0 )