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authorEric Dumazet <edumazet@google.com>2020-01-06 17:10:39 +0300
committerDavid S. Miller <davem@davemloft.net>2020-01-08 23:40:47 +0300
commitd9e15a2733067c9328fb56d98fe8e574fa19ec31 (patch)
treefcba680930ee393e0c16aa75b782975674cba89c /net/sched
parentb969fee12b6330fd6a0b15337a314d5b5ee56916 (diff)
downloadlinux-d9e15a2733067c9328fb56d98fe8e574fa19ec31.tar.xz
pkt_sched: fq: do not accept silly TCA_FQ_QUANTUM
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>
Diffstat (limited to 'net/sched')
-rw-r--r--net/sched/sch_fq.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/net/sched/sch_fq.c b/net/sched/sch_fq.c
index ff4c5e9d0d77..a5a295477ecc 100644
--- a/net/sched/sch_fq.c
+++ b/net/sched/sch_fq.c
@@ -786,10 +786,12 @@ 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])