[PATCH 4/8] cifs: replace memset by memzero_explicit

From: Julia Lawall
Date: Sun Nov 30 2014 - 12:05:42 EST


From: Julia Lawall <julia@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@xxxxxxx>

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

fs/cifs/smbencrypt.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/cifs/smbencrypt.c b/fs/cifs/smbencrypt.c
index 6c15663..6512c19 100644
--- a/fs/cifs/smbencrypt.c
+++ b/fs/cifs/smbencrypt.c
@@ -221,7 +221,7 @@ E_md4hash(const unsigned char *passwd, unsigned char *p16,
}

rc = mdfour(p16, (unsigned char *) wpwd, len * sizeof(__le16));
- memset(wpwd, 0, 129 * sizeof(__le16));
+ memzero_explicit(wpwd, 129 * sizeof(__le16));

return rc;
}

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