From 8f52a8a8c06ba767ce0be2cf8d1406b7b24878a2 Mon Sep 17 00:00:00 2001
From: Andrzej Kurek <andrzej.kurek@arm.com>
Date: Mon, 8 Jun 2020 11:02:22 -0400
Subject: [PATCH] Improve the Hamming distance of ssl_hs_is_proper_fragment
return values
Signed-off-by: Andrzej Kurek <andrzej.kurek@arm.com>
---
library/ssl_tls.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index c92ab7f39..c79fe7d86 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -56,6 +56,8 @@
#include "mbedtls/oid.h"
#endif
+#define PROPER_HS_FRAGMENT 0x75555555
+
#if defined(MBEDTLS_USE_TINYCRYPT)
static int uecc_rng_wrapper( uint8_t *dest, unsigned int size )
{
@@ -4735,7 +4737,7 @@ static int ssl_hs_is_proper_fragment( mbedtls_ssl_context *ssl )
mbedtls_platform_memcmp( ssl->in_msg + 6, "\0\0\0", 3 ) != 0 ||
mbedtls_platform_memcmp( ssl->in_msg + 9, ssl->in_msg + 1, 3 ) != 0 )
{
- return( 1 );
+ return( PROPER_HS_FRAGMENT );
}
return( 0 );
}
@@ -4928,7 +4930,7 @@ int mbedtls_ssl_prepare_handshake_record( mbedtls_ssl_context *ssl )
* messages; the commonality is that both handshake fragments and
* future messages cannot be forwarded immediately to the
* handshake logic layer. */
- if( ssl_hs_is_proper_fragment( ssl ) == 1 )
+ if( ssl_hs_is_proper_fragment( ssl ) == PROPER_HS_FRAGMENT )
{
MBEDTLS_SSL_DEBUG_MSG( 2, ( "found fragmented DTLS handshake message" ) );
return( MBEDTLS_ERR_SSL_EARLY_MESSAGE );
@@ -6052,7 +6054,7 @@ static int ssl_buffer_message( mbedtls_ssl_context *ssl )
size_t reassembly_buf_sz;
hs_buf->is_fragmented =
- ( ssl_hs_is_proper_fragment( ssl ) == 1 );
+ ( ssl_hs_is_proper_fragment( ssl ) == PROPER_HS_FRAGMENT );
/* We copy the message back into the input buffer
* after reassembly, so check that it's not too large.