[PATCH 3.2 054/147] xfrm_user: fix info leak in build_aevent()

[Ben Hutchings]

3.2.95-rc1 review patch.  If anyone has any objections, please let me know.

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

From: Mathias Krause <minipli@xxxxxxxxxxxxxx>

commit 931e79d7a7ddee4709c56b39de169a36804589a1 upstream.

The memory reserved to dump the ID of the xfrm state includes a padding
byte in struct xfrm_usersa_id added by the compiler for alignment. To
prevent the heap info leak, memset(0) the sa_id before filling it.

Cc: Jamal Hadi Salim <jhs@xxxxxxxxxxxx>
Fixes: d51d081d6504 ("[IPSEC]: Sync series - user")
Signed-off-by: Mathias Krause <minipli@xxxxxxxxxxxxxx>
Signed-off-by: Steffen Klassert <steffen.klassert@xxxxxxxxxxx>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 net/xfrm/xfrm_user.c | 1 +
 1 file changed, 1 insertion(+)

--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -1719,6 +1719,7 @@ static int build_aevent(struct sk_buff *
 		return -EMSGSIZE;
 
 	id = nlmsg_data(nlh);
+	memset(&id->sa_id, 0, sizeof(id->sa_id));
 	memcpy(&id->sa_id.daddr, &x->id.daddr,sizeof(x->id.daddr));
 	id->sa_id.spi = x->id.spi;
 	id->sa_id.family = x->props.family;