netdev - [PATCH] net_sched: sch_hfsc: fix classification loops

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-Id: <1273860494-23328-1-git-send-email-kaber@trash.net>
Date:	Fri, 14 May 2010 20:08:14 +0200
From:	kaber@...sh.net
To:	davem@...emloft.net
Cc:	netdev@...r.kernel.org
Subject: [PATCH] net_sched: sch_hfsc: fix classification loops

From: Patrick McHardy <kaber@...sh.net>

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 <pstaszewski@...are.pl>
Signed-off-by: Patrick McHardy <kaber@...sh.net>
---
 net/sched/sch_hfsc.c |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/net/sched/sch_hfsc.c b/net/sched/sch_hfsc.c
index b38b39c..a435cf1 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 */
-- 
1.7.0.4

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html