[PATCH 02/23] [PATCH] dm-crypt: zero key before freeing it

[Chris Wright <chrisw@sous-sol.org>]

[-- Attachment #1: dm-crypt-zero-key-before-freeing-it.patch --]
[-- Type: text/plain, Size: 1223 bytes --]

-stable review patch.  If anyone has any objections, please let us know.
------------------

Zap the memory before freeing it so we don't leave crypto information
around in memory.

Signed-off-by: Stefan Rompf <stefan@loplof.de>
Acked-by: Clemens Fruhwirth <clemens@endorphin.org>
Acked-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
---

 drivers/md/dm-crypt.c |    5 +++++
 1 files changed, 5 insertions(+)

Index: linux-2.6.15.3/drivers/md/dm-crypt.c
===================================================================
--- linux-2.6.15.3.orig/drivers/md/dm-crypt.c
+++ linux-2.6.15.3/drivers/md/dm-crypt.c
@@ -690,6 +690,8 @@ bad3:
 bad2:
 	crypto_free_tfm(tfm);
 bad1:
+	/* Must zero key material before freeing */
+	memset(cc, 0, sizeof(*cc) + cc->key_size * sizeof(u8));
 	kfree(cc);
 	return -EINVAL;
 }
@@ -706,6 +708,9 @@ static void crypt_dtr(struct dm_target *
 		cc->iv_gen_ops->dtr(cc);
 	crypto_free_tfm(cc->tfm);
 	dm_put_device(ti, cc->dev);
+
+	/* Must zero key material before freeing */
+	memset(cc, 0, sizeof(*cc) + cc->key_size * sizeof(u8));
 	kfree(cc);
 }
 

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