[PATCH net v1 1/1] tipc: fix nullptr crash during subscription cancel

[PATCH net v1 1/1] tipc: fix nullptr crash during subscription cancel

[Parthasarathy Bhuvaragan]

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>
---
 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 69ee2eeef968..f9ff73a8d815 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 */
-- 
2.1.4


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Re: [PATCH net v1 1/1] tipc: fix nullptr crash during subscription cancel

[David Miller]

From: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com>
Date: Thu, 3 Mar 2016 17:54:54 +0100

> 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>

Applied.