diff options
| author | Eric Dumazet <edumazet@google.com> | 2020-01-06 06:10:39 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-01-12 12:17:26 +0100 |
| commit | 94ac4a4d938f51a18a51286fd94a46c1d6558103 (patch) | |
| tree | 113b8d835c306da820f1050824bc7d297dc98f3c /net/sched | |
| parent | 77b07bbf47e4c447bd36c97a8b597865ebff2d49 (diff) | |
pkt_sched: fq: do not accept silly TCA_FQ_QUANTUM
[ Upstream commit d9e15a2733067c9328fb56d98fe8e574fa19ec31 ]
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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net/sched')
| -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 4808713c73b9..1ee2b77f607b 100644 --- a/net/sched/sch_fq.c +++ b/net/sched/sch_fq.c @@ -735,10 +735,12 @@ 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]) |