From 23cdd8c3cbe9d790f23d7f9ae14e9b828f56f69c Mon Sep 17 00:00:00 2001
From: Richard Alpe <richard.alpe@ericsson.com>
Date: Mon, 16 May 2016 11:14:54 +0200
Subject: tipc: check nl sock before parsing nested attributes

[ Upstream commit 45e093ae2830cd1264677d47ff9a95a71f5d9f9c ]

Make sure the socket for which the user is listing publication exists
before parsing the socket netlink attributes.

Prior to this patch a call without any socket caused a NULL pointer
dereference in tipc_nl_publ_dump().

Upstream-Status: Backport
CVE: CVE-2016-4951

Tested-and-reported-by: Baozeng Ding <sploving1@gmail.com>
Signed-off-by: Richard Alpe <richard.alpe@ericsson.com>
Acked-by: Jon Maloy <jon.maloy@ericsson.cm>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sona Sarmadi <sona.sarmadi@enea.com>
---
 net/tipc/socket.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index e53003c..9b713e0 100644
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -2814,6 +2814,9 @@ int tipc_nl_publ_dump(struct sk_buff *skb, struct netlink_callback *cb)
 		if (err)
 			return err;
 
+		if (!attrs[TIPC_NLA_SOCK])
+			return -EINVAL;
+
 		err = nla_parse_nested(sock, TIPC_NLA_SOCK_MAX,
 				       attrs[TIPC_NLA_SOCK],
 				       tipc_nl_sock_policy);
-- 
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