[ 080/108] xfrm_user: fix info leak in copy_to_user_policy()

[Ben Hutchings]

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

------------------

From: Mathias Krause <minipli@xxxxxxxxxxxxxx>

[ Upstream commit 7b789836f434c87168eab067cfbed1ec4783dffd ]

The memory reserved to dump the xfrm policy includes multiple padding
bytes added by the compiler for alignment (padding bytes in struct
xfrm_selector and struct xfrm_userpolicy_info). Add an explicit
memset(0) before filling the buffer to avoid the heap info leak.

Signed-off-by: Mathias Krause <minipli@xxxxxxxxxxxxxx>
Acked-by: Steffen Klassert <steffen.klassert@xxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 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 f252cae..1d222e9 100644
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -1300,6 +1300,7 @@ static void copy_from_user_policy(struct xfrm_policy *xp, struct xfrm_userpolicy
 
 static void copy_to_user_policy(struct xfrm_policy *xp, struct xfrm_userpolicy_info *p, int dir)
 {
+	memset(p, 0, sizeof(*p));
 	memcpy(&p->sel, &xp->selector, sizeof(p->sel));
 	memcpy(&p->lft, &xp->lft, sizeof(p->lft));
 	memcpy(&p->curlft, &xp->curlft, sizeof(p->curlft));


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