dm crypt: use memzero_explicit for on-stack buffer

commit 1a71d6ffe18c0d0f03fc8531949cc8ed41d702ee upstream.

Use memzero_explicit to cleanup sensitive data allocated on stack
to prevent the compiler from optimizing and removing memset() calls.

Signed-off-by: Milan Broz <gmazyland@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 9533f835ce07fb4913e507dbd5f1350fa6ab28e3..4a8d19d0a5a4ab34a241ca912ec0951246b6941a 100644 (file)
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -709,7 +709,7 @@ static int crypt_iv_tcw_whitening(struct crypt_config *cc,
        for (i = 0; i < ((1 << SECTOR_SHIFT) / 8); i++)
                crypto_xor(data + i * 8, buf, 8);
 out:
-       memset(buf, 0, sizeof(buf));
+       memzero_explicit(buf, sizeof(buf));
        return r;
 }