From a2f79227138c71e08627af5f8961197364edbc98 Mon Sep 17 00:00:00 2001 From: Patrick McHardy Date: Fri, 14 May 2010 08:08:14 +0000 Subject: [PATCH] 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: Pawel Staszewski Signed-off-by: Patrick McHardy Signed-off-by: David S. Miller --- net/sched/sch_hfsc.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/net/sched/sch_hfsc.c b/net/sched/sch_hfsc.c index b38b39c60752..a435cf13cc27 100644 --- a/net/sched/sch_hfsc.c +++ b/net/sched/sch_hfsc.c @@ -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 */ -- 2.39.2