queue-4.4/sched-core-check-quota-and-period-overflow-at-usec-t.patch

   1 From 7b117a3e1c3bfe529ae3ca8845809f6a18b0ff17 Mon Sep 17 00:00:00 2001
   2 From: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
   3 Date: Wed, 27 Feb 2019 11:10:20 +0300
   4 Subject: sched/core: Check quota and period overflow at usec to nsec
   5  conversion
   6
   7 [ Upstream commit 1a8b4540db732ca16c9e43ac7c08b1b8f0b252d8 ]
   8
   9 Large values could overflow u64 and pass following sanity checks.
  10
  11  # echo 18446744073750000 > cpu.cfs_period_us
  12  # cat cpu.cfs_period_us
  13  40448
  14
  15  # echo 18446744073750000 > cpu.cfs_quota_us
  16  # cat cpu.cfs_quota_us
  17  40448
  18
  19 After this patch they will fail with -EINVAL.
  20
  21 Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
  22 Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
  23 Cc: Linus Torvalds <torvalds@linux-foundation.org>
  24 Cc: Peter Zijlstra <peterz@infradead.org>
  25 Cc: Thomas Gleixner <tglx@linutronix.de>
  26 Link: http://lkml.kernel.org/r/155125502079.293431.3947497929372138600.stgit@buzz
  27 Signed-off-by: Ingo Molnar <mingo@kernel.org>
  28 Signed-off-by: Sasha Levin <sashal@kernel.org>
  29 ---
  30  kernel/sched/core.c | 7 ++++++-
  31  1 file changed, 6 insertions(+), 1 deletion(-)
  32
  33 diff --git a/kernel/sched/core.c b/kernel/sched/core.c
  34 index d35a7d528ea66..1ef2fb4bbd6bd 100644
  35 --- a/kernel/sched/core.c
  36 +++ b/kernel/sched/core.c
  37 @@ -8460,8 +8460,10 @@ int tg_set_cfs_quota(struct task_group *tg, long cfs_quota_us)
  38         period = ktime_to_ns(tg->cfs_bandwidth.period);
  39         if (cfs_quota_us < 0)
  40                 quota = RUNTIME_INF;
  41 -       else
  42 +       else if ((u64)cfs_quota_us <= U64_MAX / NSEC_PER_USEC)
  43                 quota = (u64)cfs_quota_us * NSEC_PER_USEC;
  44 +       else
  45 +               return -EINVAL;
  46
  47         return tg_set_cfs_bandwidth(tg, period, quota);
  48  }
  49 @@ -8483,6 +8485,9 @@ int tg_set_cfs_period(struct task_group *tg, long cfs_period_us)
  50  {
  51         u64 quota, period;
  52
  53 +       if ((u64)cfs_period_us > U64_MAX / NSEC_PER_USEC)
  54 +               return -EINVAL;
  55 +
  56         period = (u64)cfs_period_us * NSEC_PER_USEC;
  57         quota = tg->cfs_bandwidth.quota;
  58
  59 --
  60 2.20.1
  61