[PATCH 2/8 v2] sparc64: replace memset by memzero_explicit

From: Julia Lawall
Date: Sun Nov 30 2014 - 12:11:36 EST


From: Julia Lawall <Julia.Lawall@xxxxxxx>

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/)

// <smpl>
@@
identifier x;
type T;
@@

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

This change was suggested by Daniel Borkmann <dborkman@xxxxxxxxxx>

Signed-off-by: Julia Lawall <Julia.Lawall@xxxxxxx>

---
Daniel Borkmann suggested that these patches could go through Herbert Xu's
cryptodev tree.

I was not able to compile these.

v2: fixed email address

arch/sparc/crypto/sha256_glue.c | 2 +-
arch/sparc/crypto/sha512_glue.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/sparc/crypto/sha512_glue.c b/arch/sparc/crypto/sha512_glue.c
index 9fff885..11eb36c 100644
--- a/arch/sparc/crypto/sha512_glue.c
+++ b/arch/sparc/crypto/sha512_glue.c
@@ -139,7 +139,7 @@ static int sha384_sparc64_final(struct shash_desc *desc, u8 *hash)
sha512_sparc64_final(desc, D);

memcpy(hash, D, 48);
- memset(D, 0, 64);
+ memzero_explicit(D, 64);

return 0;
}
diff --git a/arch/sparc/crypto/sha256_glue.c b/arch/sparc/crypto/sha256_glue.c
index 41f27cc..285268c 100644
--- a/arch/sparc/crypto/sha256_glue.c
+++ b/arch/sparc/crypto/sha256_glue.c
@@ -135,7 +135,7 @@ static int sha224_sparc64_final(struct shash_desc *desc, u8 *hash)
sha256_sparc64_final(desc, D);

memcpy(hash, D, SHA224_DIGEST_SIZE);
- memset(D, 0, SHA256_DIGEST_SIZE);
+ memzero_explicit(D, SHA256_DIGEST_SIZE);

return 0;
}

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