blob: d148244feb8a6dc81976460e0a61a0ed2fe2a946 [file] [log] [blame]
From 7a6bda3fbd99ef8cd51c039de8e48e31045e6e61 Mon Sep 17 00:00:00 2001
From: Eric Dumazet <edumazet@google.com>
Date: Mon, 6 Jan 2020 06:10:39 -0800
Subject: [PATCH] pkt_sched: fq: do not accept silly TCA_FQ_QUANTUM
commit d9e15a2733067c9328fb56d98fe8e574fa19ec31 upstream.
As diagnosed by Florian :
If TCA_FQ_QUANTUM is set to 0x80000000, fq_deueue()
can loop forever in :
if (f->credit <= 0) {
f->credit += q->quantum;
goto begin;
}
... because f->credit is either 0 or -2147483648.
Let's limit TCA_FQ_QUANTUM to no more than 1 << 20 :
This max value should limit risks of breaking user setups
while fixing this bug.
Fixes: afe4fd062416 ("pkt_sched: fq: Fair Queue packet scheduler")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Diagnosed-by: Florian Westphal <fw@strlen.de>
Reported-by: syzbot+dc9071cc5a85950bdfce@syzkaller.appspotmail.com
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
diff --git a/net/sched/sch_fq.c b/net/sched/sch_fq.c
index 78ecdf146882..712ad248d6a7 100644
--- a/net/sched/sch_fq.c
+++ b/net/sched/sch_fq.c
@@ -787,10 +787,12 @@ static int fq_change(struct Qdisc *sch, struct nlattr *opt,
if (tb[TCA_FQ_QUANTUM]) {
u32 quantum = nla_get_u32(tb[TCA_FQ_QUANTUM]);
- if (quantum > 0)
+ if (quantum > 0 && quantum <= (1 << 20)) {
q->quantum = quantum;
- else
+ } else {
+ NL_SET_ERR_MSG_MOD(extack, "invalid quantum");
err = -EINVAL;
+ }
}
if (tb[TCA_FQ_INITIAL_QUANTUM])
--
2.7.4