tipc: fix an infoleak in tipc_nl_compat_link_dump

link_info.str is a char array of size 60. Memory after the NULL
byte is not initialized. Sending the whole object out can cause
a leak.
Signed-off-by: Kangjie Lu <kjlu@gatech.edu>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit 5d2be142)
CVE-2016-5243
BugLink: https://bugs.launchpad.net/bugs/1589036Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
Acked-by: Brad Figg <brad.figg@canonical.com>
Acked-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>

net/tipc/netlink_compat.c

@@ -574,7 +574,8 @@ static int tipc_nl_compat_link_dump(struct tipc_nl_compat_msg *msg,
 
 	link_info.dest = nla_get_flag(link[TIPC_NLA_LINK_DEST]);
 	link_info.up = htonl(nla_get_flag(link[TIPC_NLA_LINK_UP]));
-	strcpy(link_info.str, nla_data(link[TIPC_NLA_LINK_NAME]));
+	nla_strlcpy(link_info.str, nla_data(link[TIPC_NLA_LINK_NAME]),
+		    TIPC_MAX_LINK_NAME);
 
 	return tipc_add_tlv(msg->rep, TIPC_TLV_LINK_INFO,
 			    &link_info, sizeof(link_info));