[PATCH 2/2] tipc: fix nl compat regression for link statistics

[Luis Henriques]

From: Richard Alpe <richard.alpe at ericsson.com>

Fix incorrect use of nla_strlcpy() where the first NLA_HDRLEN bytes
of the link name where left out.

Making the output of tipc-config -ls look something like:
Link statistics:
dcast-link
1:data0-1.1.2:data0
1:data0-1.1.3:data0

Also, for the record, the patch that introduce this regression
claims "Sending the whole object out can cause a leak". Which isn't
very likely as this is a compat layer, where the data we are parsing
is generated by us and we know the string to be NULL terminated. But
you can of course never be to secure.

Fixes: 5d2be1422e02 (tipc: fix an infoleak in tipc_nl_compat_link_dump)
Signed-off-by: Richard Alpe <richard.alpe at ericsson.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
(cherry picked from commit 55e77a3e8297581c919b45adcc4d0815b69afa84)
CVE-2016-5243
BugLink: https://bugs.launchpad.net/bugs/1589036
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 net/tipc/netlink_compat.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/tipc/netlink_compat.c b/net/tipc/netlink_compat.c
index f4f27c7c54fb..a0c90572d0e5 100644
--- a/net/tipc/netlink_compat.c
+++ b/net/tipc/netlink_compat.c
@@ -574,7 +574,7 @@ 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]));
-	nla_strlcpy(link_info.str, nla_data(link[TIPC_NLA_LINK_NAME]),
+	nla_strlcpy(link_info.str, link[TIPC_NLA_LINK_NAME],
 		    TIPC_MAX_LINK_NAME);
 
 	return tipc_add_tlv(msg->rep, TIPC_TLV_LINK_INFO,