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authorEric Dumazet <edumazet@google.com>2020-04-27 04:19:07 +0300
committerDavid S. Miller <davem@davemloft.net>2020-04-27 21:49:57 +0300
commitdf4953e4e997e273501339f607b77953772e3559 (patch)
treeb6ebd6e34cfd0d4459e5f103f3b633f8cc1504f5 /net/sched/sch_sfq.c
parentcf7fc3af87b2d767f55eeec9faeb4b45b929341c (diff)
downloadlinux-df4953e4e997e273501339f607b77953772e3559.tar.xz
sch_sfq: validate silly quantum values
syzbot managed to set up sfq so that q->scaled_quantum was zero, triggering an infinite loop in sfq_dequeue() More generally, we must only accept quantum between 1 and 2^18 - 7, meaning scaled_quantum must be in [1, 0x7FFF] range. Otherwise, we also could have a loop in sfq_dequeue() if scaled_quantum happens to be 0x8000, since slot->allot could indefinitely switch between 0 and 0x8000. Fixes: eeaeb068f139 ("sch_sfq: allow big packets and be fair") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot+0251e883fe39e7a0cb0a@syzkaller.appspotmail.com Cc: Jason A. Donenfeld <Jason@zx2c4.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sched/sch_sfq.c')
-rw-r--r--net/sched/sch_sfq.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/net/sched/sch_sfq.c b/net/sched/sch_sfq.c
index c787d4d46017..5a6def5e4e6d 100644
--- a/net/sched/sch_sfq.c
+++ b/net/sched/sch_sfq.c
@@ -637,6 +637,15 @@ static int sfq_change(struct Qdisc *sch, struct nlattr *opt)
if (ctl->divisor &&
(!is_power_of_2(ctl->divisor) || ctl->divisor > 65536))
return -EINVAL;
+
+ /* slot->allot is a short, make sure quantum is not too big. */
+ if (ctl->quantum) {
+ unsigned int scaled = SFQ_ALLOT_SIZE(ctl->quantum);
+
+ if (scaled <= 0 || scaled > SHRT_MAX)
+ return -EINVAL;
+ }
+
if (ctl_v1 && !red_check_params(ctl_v1->qth_min, ctl_v1->qth_max,
ctl_v1->Wlog))
return -EINVAL;