tipc: check nl sock before parsing nested attributes

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().

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>
(cherry picked from commit 45e093ae2830cd1264677d47ff9a95a71f5d9f9c)

Orabug: 23347071
CVE: CVE-2016-4951

Signed-off-by: Manjunath Govindashetty <manjunath.govindashetty@oracle.com>

diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index f485600c4507bc152cef654ae5667a03a52d990c..03f39064f6de6f7d8097802be7e08456083b7bf0 100644 (file)
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -2803,6 +2803,9 @@ 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);