commit 54e1c30d1bae8c4e65dd96147120715b074c308c
author Gilles Peskine <gilles.peskine@arm.com> Mon Apr 06 16:34:31 2020 +0200
committer GitHub <noreply@github.com> Mon Apr 06 16:34:31 2020 +0200
tree ec3d61afd533a81d6c23256da11d804697e25a38
parent 6d41f4cc42ed43627b86575c96575426f91e94e0
parent 3ab121a6034aa36a895e1bbb5daab7a27d8b14c3

Merge pull request #3160 from gilles-peskine-arm/hkdf_expand-initialize_t-development

hkdf_expand: explicitly initialize t

library/hkdf.c

diff --git a/library/hkdf.c b/library/hkdf.c
index 379035d..82df597 100644
--- a/library/hkdf.c
+++ b/library/hkdf.c
@@ -115,7 +115,7 @@
 
     n = okm_len / hash_len;
 
-    if( (okm_len % hash_len) != 0 )
+    if( okm_len % hash_len != 0 )
     {
         n++;
     }
@@ -131,11 +131,13 @@
 
     mbedtls_md_init( &ctx );
 
-    if( (ret = mbedtls_md_setup( &ctx, md, 1) ) != 0 )
+    if( ( ret = mbedtls_md_setup( &ctx, md, 1 ) ) != 0 )
     {
         goto exit;
     }
 
+    memset( t, 0, hash_len );
+
     /*
      * Compute T = T(1) | T(2) | T(3) | ... | T(N)
      * Where T(N) is defined in RFC 5869 Section 2.3