commit 346177255931fb1e3514e124a1f598715a5fe92d
author Paul Bakker <p.j.bakker@polarssl.org> Fri Jun 13 17:20:13 2014 +0200
committer Paul Bakker <p.j.bakker@polarssl.org> Sat Jun 14 16:46:03 2014 +0200
tree da658994944be861b8b2a1001c9b759976276891
parent bbcb1ce7030575d708700ca205800e847d846402

Introduce polarssl_zeroize() instead of memset() for zeroization

library/md_wrap.c

diff --git a/library/md_wrap.c b/library/md_wrap.c
index 9627878..6447622 100644
--- a/library/md_wrap.c
+++ b/library/md_wrap.c
@@ -74,6 +74,11 @@
 
 #include <stdlib.h>
 
+/* Implementation that should never be optimized out by the compiler */
+static void polarssl_zeroize( void *v, size_t n ) {
+    volatile unsigned char *p = v; while( n-- ) *p++ = 0;
+}
+
 #if defined(POLARSSL_MD2_C)
 
 static void md2_starts_wrap( void *ctx )
@@ -132,6 +137,7 @@
 
 static void md2_ctx_free( void *ctx )
 {
+    polarssl_zeroize( ctx, sizeof( md2_context ) );
     polarssl_free( ctx );
 }
 
@@ -221,6 +227,7 @@
 
 static void md4_ctx_free( void *ctx )
 {
+    polarssl_zeroize( ctx, sizeof( md4_context ) );
     polarssl_free( ctx );
 }
 
@@ -308,6 +315,7 @@
 
 static void md5_ctx_free( void *ctx )
 {
+    polarssl_zeroize( ctx, sizeof( md5_context ) );
     polarssl_free( ctx );
 }
 
@@ -395,6 +403,7 @@
 
 static void ripemd160_ctx_free( void *ctx )
 {
+    polarssl_zeroize( ctx, sizeof( ripemd160_context ) );
     polarssl_free( ctx );
 }
 
@@ -482,6 +491,7 @@
 
 static void sha1_ctx_free( void *ctx )
 {
+    polarssl_zeroize( ctx, sizeof( sha1_context ) );
     polarssl_free( ctx );
 }
 
@@ -585,6 +595,7 @@
 
 static void sha224_ctx_free( void *ctx )
 {
+    polarssl_zeroize( ctx, sizeof( sha256_context ) );
     polarssl_free( ctx );
 }
 
@@ -681,6 +692,7 @@
 
 static void sha256_ctx_free( void *ctx )
 {
+    polarssl_zeroize( ctx, sizeof( sha256_context ) );
     polarssl_free( ctx );
 }
 
@@ -781,6 +793,7 @@
 
 static void sha384_ctx_free( void *ctx )
 {
+    polarssl_zeroize( ctx, sizeof( sha512_context ) );
     polarssl_free( ctx );
 }
 
@@ -877,6 +890,7 @@
 
 static void sha512_ctx_free( void *ctx )
 {
+    polarssl_zeroize( ctx, sizeof( sha512_context ) );
     polarssl_free( ctx );
 }