[PATCH 4.2.y-ckt 02/98] tipc: fix nullptr crash during subscription cancel

Kamal Mostafa
2016-03-15T23:29:56Z

From: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com>

commit 4de13d7ed6ffdcbb34317acaa9236f121176f5f8 upstream.

commit 4d5cfcba2f6e ('tipc: fix connection abort during subscription
cancel'), removes the check for a valid subscription before calling
tipc_nametbl_subscribe().

This will lead to a nullptr exception when we process a
subscription cancel request. For a cancel request, a null
subscription is passed to tipc_nametbl_subscribe() resulting
in exception.

In this commit, we call tipc_nametbl_subscribe() only for
a valid subscription.

Fixes: 4d5cfcba2f6e ('tipc: fix connection abort during subscription cancel')
Reported-by: Anders Widell <anders.widell@ericsson.com>
Signed-off-by: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com>
Acked-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
net/tipc/subscr.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/tipc/subscr.c b/net/tipc/subscr.c
index 69ee2ee..f9ff73a 100644
--- a/net/tipc/subscr.c
+++ b/net/tipc/subscr.c
@@ -296,7 +296,8 @@ static void tipc_subscrb_rcv_cb(struct net *net, int conid,
if (tipc_subscrp_create(net, (struct tipc_subscr *)buf, subscrb, &sub))
return tipc_conn_terminate(tn->topsrv, subscrb->conid);

- tipc_nametbl_subscribe(sub);
+ if (sub)
+ tipc_nametbl_subscribe(sub);
}

/* Handle one request to establish a new subscriber */
--
2.7.0