crypto: powerpc – replace memset by memzero_explicit

Author: Julia Lawall <Julia.Lawall@lip6.fr>

Memset on a local variable may be removed when it is called just before the
variable goes out of scope.  Using memzero_explicit defeats this
optimization.  A simplified version of the semantic patch that makes this
change is as follows: (http://coccinelle.lip6.fr/)

// 
@@
identifier x;
type T;
@@

{
... when any
T x[...];
... when any
    when exists
- memset
+ memzero_explicit
  (x,
-0,
  ...)
... when != x
    when strict
}
// 

This change was suggested by Daniel Borkmann 

Signed-off-by: Julia Lawall 
Acked-by: Michael Ellerman 
Signed-off-by: Herbert Xu 

---
 arch/powerpc/crypto/sha1.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
 
diff --git a/arch/powerpc/crypto/sha1.c b/arch/powerpc/crypto/sha1.c
index 0f88c7b..d3feba5a2 100644
--- a/arch/powerpc/crypto/sha1.c
+++ b/arch/powerpc/crypto/sha1.c
@@ -66,7 +66,7 @@ static int sha1_update(struct shash_desc *desc, const u8 *data,
 			src = data + done;
 		} while (done + 63 < len);
 
-		memset(temp, 0, sizeof(temp));
+		memzero_explicit(temp, sizeof(temp));
 		partial = 0;
 	}
 	memcpy(sctx->buffer + partial, src, len - done);