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>

diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index 12628890c2190b9cff66a12d2d2169c1192be761..3b7a79991d55ddb4dc3f6629ac37c7cd6ebf1a87 100644 (file)
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -2853,6 +2853,9 @@ 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);