diff options
| author |   Eric Dumazet <edumazet@google.com> | 2020-01-06 06:10:39 -0800 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2020-01-08 12:40:47 -0800 |
| commit | d9e15a2733067c9328fb56d98fe8e574fa19ec31 (patch) | |
| tree | fcba680930ee393e0c16aa75b782975674cba89c | |
| parent | tipc: remove meaningless assignment in Makefile (diff) | |
| download | linux-dev-d9e15a2733067c9328fb56d98fe8e574fa19ec31.tar.xz linux-dev-d9e15a2733067c9328fb56d98fe8e574fa19ec31.zip | |
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>
| -rw-r--r-- | net/sched/sch_fq.c | 6 |
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]) |