Commit a2f79227 authored by Patrick McHardy's avatar Patrick McHardy Committed by David S. Miller
Browse files

net_sched: sch_hfsc: fix classification loops 



When attaching filters to a class pointing to a class higher up in the
hierarchy, classification may enter an endless loop. Currently this is
prevented for filters that are already resolved, but not for filters
resolved at runtime.

Only allow filters to point downwards in the hierarchy, similar to what
CBQ does.

Reported-by: default avatarPawel Staszewski <pstaszewski@itcare.pl>
Signed-off-by: default avatarPatrick McHardy <kaber@trash.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent e1bc7eed

net/sched/sch_hfsc.c

+5 −1
Original line number Diff line number Diff line
@@ -1155,7 +1155,7 @@ static struct hfsc_class * 
hfsc_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr)

{

	struct hfsc_sched *q = qdisc_priv(sch);

	struct hfsc_class *cl;

	struct hfsc_class *head, *cl;

	struct tcf_result res;

	struct tcf_proto *tcf;

	int result;
@@ -1166,6 +1166,7 @@ hfsc_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr) 
			return cl;



	*qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;

	head = &q->root;

	tcf = q->root.filter_list;

	while (tcf && (result = tc_classify(skb, tcf, &res)) >= 0) {

#ifdef CONFIG_NET_CLS_ACT
@@ -1180,6 +1181,8 @@ hfsc_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr) 
		if ((cl = (struct hfsc_class *)res.class) == NULL) {

			if ((cl = hfsc_find_class(res.classid, sch)) == NULL)

				break; /* filter selected invalid classid */

			if (cl->level >= head->level)

				break; /* filter may only point downwards */

		}



		if (cl->level == 0)
@@ -1187,6 +1190,7 @@ hfsc_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr) 


		/* apply inner filter chain */

		tcf = cl->filter_list;

		head = cl;

	}



	/* classification failed, try default class */

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