[Patch 2.6] dm-crypt: zero key before freeing it

[Stefan Rompf <stefan@loplof.de>]

Hi Andrew,

dm-crypt does not clear struct crypt_config before freeing it. Thus, 
information on the key could leak f.e. to a swsusp image even after the 
encrypted device has been removed. The attached patch against 2.6.14 / 2.6.15 
fixes it.

Signed-off-by: Stefan Rompf <stefan@loplof.de>
Acked-by: Clemens Fruhwirth <clemens@endorphin.org>

--- linux-2.6.14.4/drivers/md/dm-crypt.c.old	2005-12-16 18:27:05.000000000 +0100
+++ linux-2.6.14.4/drivers/md/dm-crypt.c	2005-12-28 12:49:13.000000000 +0100
@@ -694,6 +694,7 @@ bad3:
 bad2:
 	crypto_free_tfm(tfm);
 bad1:
+	memset(cc, 0, sizeof(*cc) + cc->key_size * sizeof(u8));
 	kfree(cc);
 	return -EINVAL;
 }
@@ -710,6 +711,7 @@ static void crypt_dtr(struct dm_target *
 		cc->iv_gen_ops->dtr(cc);
 	crypto_free_tfm(cc->tfm);
 	dm_put_device(ti, cc->dev);
+	memset(cc, 0, sizeof(*cc) + cc->key_size * sizeof(u8));
 	kfree(cc);
 }