xfrm_user: fix info leak in build_expire()
The memory reserved to dump the expired xfrm state includes padding
bytes in struct xfrm_user_expire added by the compiler for alignment. To
prevent the heap info leak, memset(0) the remainder of the struct.
Initializing the whole structure isn't needed as copy_to_user_state()
already takes care of clearing the padding bytes within the 'state'
member.
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index c33516e..2cbdc81 100644
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -2578,6 +2578,8 @@
ue = nlmsg_data(nlh);
copy_to_user_state(x, &ue->state);
ue->hard = (c->data.hard != 0) ? 1 : 0;
+ /* clear the padding bytes */
+ memset(&ue->hard + 1, 0, sizeof(*ue) - offsetofend(typeof(*ue), hard));
err = xfrm_mark_put(skb, &x->mark);
if (err)