xfrm_user: fix info leak in build_aevent()

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@mojatatu.com>
Fixes: d51d081d6504 ("[IPSEC]: Sync series - user")
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index 005c73ba45245684719d6a8420899c82f606bd7c..963222e89dbe79d36314919fcdd53a90d53794cd 100644 (file)
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -1719,6 +1719,7 @@ static int build_aevent(struct sk_buff *skb, struct xfrm_state *x, const struct
                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;