tipc: fix nullpointer bug when subscribing to events (7fe8097c) · Commits · 戴 / test

If a subscription request is sent to a topology server connection, and any error occurs (malformed request, oom or limit reached) while processing this request, TIPC should terminate the subscriber connection. While doing so, it tries to access fields in an already freed (or never allocated) subscription element leading to a nullpointer exception. We fix this by removing the subscr_terminate function and terminate the connection immediately upon any subscription failure. Signed-off-by:

Erik Hugne <erik.hugne@ericsson.com> Reviewed-by:

Jon Maloy <jon.maloy@ericsson.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

net/tipc/subscr.c

+4 −19

Original line number	Diff line number	Diff line
		@@ -162,19 +162,6 @@ static void subscr_del(struct tipc_subscription *sub)
		atomic_dec(&tn->subscription_count);
		}

		/**
		* subscr_terminate - terminate communication with a subscriber
		*
		* Note: Must call it in process context since it might sleep.
		*/
		static void subscr_terminate(struct tipc_subscription *sub)
		{
		struct tipc_subscriber *subscriber = sub->subscriber;
		struct tipc_net *tn = net_generic(sub->net, tipc_net_id);

		tipc_conn_terminate(tn->topsrv, subscriber->conid);
		}

		static void subscr_release(struct tipc_subscriber *subscriber)
		{
		struct tipc_subscription *sub;
		@@ -312,16 +299,14 @@ static void subscr_conn_msg_event(struct net *net, int conid,
		{
		struct tipc_subscriber *subscriber = usr_data;
		struct tipc_subscription *sub = NULL;
		struct tipc_net *tn = net_generic(net, tipc_net_id);

		spin_lock_bh(&subscriber->lock);
		if (subscr_subscribe(net, (struct tipc_subscr *)buf, subscriber,
		&sub) < 0) {
		spin_unlock_bh(&subscriber->lock);
		subscr_terminate(sub);
		return;
		}
		subscr_subscribe(net, (struct tipc_subscr *)buf, subscriber, &sub);
		if (sub)
		tipc_nametbl_subscribe(sub);
		else
		tipc_conn_terminate(tn->topsrv, subscriber->conid);
		spin_unlock_bh(&subscriber->lock);
		}

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