[ 030/120] xfrm_user: fix info leak in copy_to_user_tmpl()

Greg Kroah-Hartman
2012-10-11T01:19:43Z

From: Mathias Krause <minipli@googlemail.com>

[ Upstream commit 1f86840f897717f86d523a13e99a447e6a5d2fa5 ]

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.

Signed-off-by: Mathias Krause <minipli@googlemail.com>
Cc: Brad Spengler <spender@grsecurity.net>
Acked-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/xfrm/xfrm_user.c | 1 +
1 file changed, 1 insertion(+)

--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -1405,6 +1405,7 @@ static int copy_to_user_tmpl(struct xfrm
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));