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/des.c

diff --git a/library/des.c b/library/des.c
index 2f06af3..a979096 100644
--- a/library/des.c
+++ b/library/des.c
@@ -47,6 +47,11 @@
 
 #if !defined(POLARSSL_DES_ALT)
 
+/* 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;
+}
+
 /*
  * 32-bit integer manipulation macros (big endian)
  */
@@ -519,7 +524,7 @@
     uint32_t sk[96];
 
     des3_set2key( ctx->sk, sk, key );
-    memset( sk,  0, sizeof( sk ) );
+    polarssl_zeroize( sk,  sizeof( sk ) );
 
     return( 0 );
 }
@@ -533,7 +538,7 @@
     uint32_t sk[96];
 
     des3_set2key( sk, ctx->sk, key );
-    memset( sk,  0, sizeof( sk ) );
+    polarssl_zeroize( sk,  sizeof( sk ) );
 
     return( 0 );
 }
@@ -570,7 +575,7 @@
     uint32_t sk[96];
 
     des3_set3key( ctx->sk, sk, key );
-    memset( sk, 0, sizeof( sk ) );
+    polarssl_zeroize( sk,  sizeof( sk ) );
 
     return( 0 );
 }
@@ -584,7 +589,7 @@
     uint32_t sk[96];
 
     des3_set3key( sk, ctx->sk, key );
-    memset( sk, 0, sizeof( sk ) );
+    polarssl_zeroize( sk,  sizeof( sk ) );
 
     return( 0 );
 }