tipc: fix infinite loop when dumping link monitor summary (36a50a98) · Commits · 戴 / test

When configuring the number of used bearers to MAX_BEARER and issuing command "tipc link monitor summary", the command enters infinite loop in user space. This issue happens because function tipc_nl_node_dump_monitor() returns the wrong 'prev_bearer' value when all potential monitors have been scanned. The correct behavior is to always try to scan all monitors until either the netlink message is full, in which case we return the bearer identity of the affected monitor, or we continue through the whole bearer array until we can return MAX_BEARERS. This solution also caters for the case where there may be gaps in the bearer array. Signed-off-by:

Tung Nguyen <tung.q.nguyen@dektech.com.au> Signed-off-by:

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

David S. Miller <davem@davemloft.net>

net/tipc/monitor.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -777,7 +777,7 @@ int __tipc_nl_add_monitor(struct net net, struct tipc_nl_msg msg,

		ret = tipc_bearer_get_name(net, bearer_name, bearer_id);
		if (ret \|\| !mon)
		return -EINVAL;
		return 0;

		hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
		NLM_F_MULTI, TIPC_NL_MON_GET);

net/tipc/node.c

+4 −7

Original line number	Diff line number	Diff line
		@@ -2232,8 +2232,8 @@ int tipc_nl_node_dump_monitor(struct sk_buff skb, struct netlink_callback cb)
		struct net *net = sock_net(skb->sk);
		u32 prev_bearer = cb->args[0];
		struct tipc_nl_msg msg;
		int bearer_id;
		int err;
		int i;

		if (prev_bearer == MAX_BEARERS)
		return 0;
		@@ -2243,16 +2243,13 @@ int tipc_nl_node_dump_monitor(struct sk_buff skb, struct netlink_callback cb)
		msg.seq = cb->nlh->nlmsg_seq;

		rtnl_lock();
		for (i = prev_bearer; i < MAX_BEARERS; i++) {
		prev_bearer = i;
		for (bearer_id = prev_bearer; bearer_id < MAX_BEARERS; bearer_id++) {
		err = __tipc_nl_add_monitor(net, &msg, prev_bearer);
		if (err)
		goto out;
		break;
		}

		out:
		rtnl_unlock();
		cb->args[0] = prev_bearer;
		cb->args[0] = bearer_id;

		return skb->len;
		}

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