linux-kernel - [v2.6.34-stable 070/213] xfrm_user: fix info leak in copy_to_user

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Date:	Wed, 5 Feb 2014 15:00:25 -0500
From:	Paul Gortmaker <paul.gortmaker@...driver.com>
To:	<stable@...r.kernel.org>, <linux-kernel@...r.kernel.org>
CC:	Mathias Krause <minipli@...glemail.com>,
	Brad Spengler <spender@...ecurity.net>,
	"David S. Miller" <davem@...emloft.net>,
	Paul Gortmaker <paul.gortmaker@...driver.com>
Subject: [v2.6.34-stable 070/213] xfrm_user: fix info leak in copy_to_user_tmpl()

From: Mathias Krause <minipli@...glemail.com>

                   -------------------
    This is a commit scheduled for the next v2.6.34 longterm release.
    http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git
    If you see a problem with using this for longterm, please comment.
                   -------------------

commit 1f86840f897717f86d523a13e99a447e6a5d2fa5 upstream.

The memory used for the template copy is a local stack variable. As
struct xfrm_user_tmpl contains multiple holes added by the compiler for
alignment, not initializing the memory will lead to leaking stack bytes
to userland. Add an explicit memset(0) to avoid the info leak.

Initial version of the patch by Brad Spengler.

Cc: Brad Spengler <spender@...ecurity.net>
Signed-off-by: Mathias Krause <minipli@...glemail.com>
Acked-by: Steffen Klassert <steffen.klassert@...unet.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Paul Gortmaker <paul.gortmaker@...driver.com>
---
 net/xfrm/xfrm_user.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index 2f72480e6b8d..44d18db58cbb 100644
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -1304,6 +1304,7 @@ static int copy_to_user_tmpl(struct xfrm_policy *xp, struct sk_buff *skb)
 		struct xfrm_user_tmpl *up = &vec[i];
 		struct xfrm_tmpl *kp = &xp->xfrm_vec[i];
 
+		memset(up, 0, sizeof(*up));
 		memcpy(&up->id, &kp->id, sizeof(up->id));
 		up->family = kp->encap_family;
 		memcpy(&up->saddr, &kp->saddr, sizeof(up->saddr));
-- 
1.8.5.2

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