Commit 3d09fc42 authored Jun 25, 2014 by Jon Paul Maloy Committed by David S. Miller Jun 27, 2014

tipc: eliminate case of writing to freed memory



In the function tipc_nodesub_notify() we call a function pointer
aggregated into the object to be notified, whereafter we set
the function pointer to NULL. However, in some cases the function
pointed to will free the struct containing the function pointer,
resulting in a write to already freed memory.

This bug seems to always have been there, without causing any
notable harm.

In this commit we fix the problem by inverting the order of the
zeroing and the function call.

Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent f5b26503

net/tipc/node_subscr.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -84,11 +84,13 @@ void tipc_nodesub_unsubscribe(struct tipc_node_subscr *node_sub)
		void tipc_nodesub_notify(struct list_head *nsub_list)
		{
		struct tipc_node_subscr ns, safe;
		net_ev_handler handle_node_down;

		list_for_each_entry_safe(ns, safe, nsub_list, nodesub_list) {
		if (ns->handle_node_down) {
		ns->handle_node_down(ns->usr_handle);
		handle_node_down = ns->handle_node_down;
		if (handle_node_down) {
		ns->handle_node_down = NULL;
		handle_node_down(ns->usr_handle);
		}
		}
		}

Admin message