net: sched: Fix use after free in red_enqueue()

We can't use "skb" again after passing it to qdisc_enqueue().  This is
basically identical to commit 2f09707d0c ("sch_sfb: Also store skb
len before calling child enqueue").

Fixes: d7f4f332f0 ("sch_red: update backlog as well")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Dan Carpenter 2022-10-28 18:05:00 +03:00 committed by David S. Miller
parent 06a4df5863
commit 8bdc2acd42

View File

@ -72,6 +72,7 @@ static int red_enqueue(struct sk_buff *skb, struct Qdisc *sch,
{ {
struct red_sched_data *q = qdisc_priv(sch); struct red_sched_data *q = qdisc_priv(sch);
struct Qdisc *child = q->qdisc; struct Qdisc *child = q->qdisc;
unsigned int len;
int ret; int ret;
q->vars.qavg = red_calc_qavg(&q->parms, q->vars.qavg = red_calc_qavg(&q->parms,
@ -126,9 +127,10 @@ static int red_enqueue(struct sk_buff *skb, struct Qdisc *sch,
break; break;
} }
len = qdisc_pkt_len(skb);
ret = qdisc_enqueue(skb, child, to_free); ret = qdisc_enqueue(skb, child, to_free);
if (likely(ret == NET_XMIT_SUCCESS)) { if (likely(ret == NET_XMIT_SUCCESS)) {
qdisc_qstats_backlog_inc(sch, skb); sch->qstats.backlog += len;
sch->q.qlen++; sch->q.qlen++;
} else if (net_xmit_drop_count(ret)) { } else if (net_xmit_drop_count(ret)) {
q->stats.pdrop++; q->stats.pdrop++;