From: David S. Miller <davem@davemloft.net>
Date: Mon, 18 Aug 2008 06:55:36 +0000 (-0700)
Subject: pkt_sched: Fix return value corruption in HTB and TBF.
X-Git-Tag: v2.6.27-rc4~39^2~15
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=69747650c814a8a79fef412c7416adf823293a3e;p=linux-2.6

pkt_sched: Fix return value corruption in HTB and TBF.

Based upon a bug report by Josip Rodin.

Packet schedulers should only return NET_XMIT_DROP iff
the packet really was dropped.  If the packet does reach
the device after we return NET_XMIT_DROP then TCP can
crash because it depends upon the enqueue path return
values being accurate.

Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c
index 6febd245e6..0df0df202e 100644
--- a/net/sched/sch_htb.c
+++ b/net/sched/sch_htb.c
@@ -577,7 +577,7 @@ static int htb_enqueue(struct sk_buff *skb, struct Qdisc *sch)
 			sch->qstats.drops++;
 			cl->qstats.drops++;
 		}
-		return NET_XMIT_DROP;
+		return ret;
 	} else {
 		cl->bstats.packets +=
 			skb_is_gso(skb)?skb_shinfo(skb)->gso_segs:1;
@@ -623,7 +623,7 @@ static int htb_requeue(struct sk_buff *skb, struct Qdisc *sch)
 			sch->qstats.drops++;
 			cl->qstats.drops++;
 		}
-		return NET_XMIT_DROP;
+		return ret;
 	} else
 		htb_activate(q, cl);
 
diff --git a/net/sched/sch_tbf.c b/net/sched/sch_tbf.c
index 7d3b7ff3bf..94c61598b8 100644
--- a/net/sched/sch_tbf.c
+++ b/net/sched/sch_tbf.c
@@ -123,15 +123,8 @@ static int tbf_enqueue(struct sk_buff *skb, struct Qdisc* sch)
 	struct tbf_sched_data *q = qdisc_priv(sch);
 	int ret;
 
-	if (qdisc_pkt_len(skb) > q->max_size) {
-		sch->qstats.drops++;
-#ifdef CONFIG_NET_CLS_ACT
-		if (sch->reshape_fail == NULL || sch->reshape_fail(skb, sch))
-#endif
-			kfree_skb(skb);
-
-		return NET_XMIT_DROP;
-	}
+	if (qdisc_pkt_len(skb) > q->max_size)
+		return qdisc_reshape_fail(skb, sch);
 
 	ret = qdisc_enqueue(skb, q->qdisc);
 	if (ret != 0) {