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| author |   Sasha Levin <sasha.levin@oracle.com> | 2015-12-03 15:46:48 -0500 |
|---|---|---|
| committer |   John Stultz <john.stultz@linaro.org> | 2015-12-10 22:41:05 -0800 |
| commit | 52d189f1b38810b1b483d5bac2e4fa90b9afd372 (patch) | |
| tree | 756d5bcadf6596e5256b4b9a40c4c7a259934740 /kernel/time/ntp.c | |
| parent | selftests/timers: fix write return value handlng (diff) | |
| download | linux-dev-52d189f1b38810b1b483d5bac2e4fa90b9afd372.tar.xz linux-dev-52d189f1b38810b1b483d5bac2e4fa90b9afd372.zip | |
ntp: Verify offset doesn't overflow in ntp_update_offset
We need to make sure that the offset is valid before manipulating it,
otherwise it might overflow on the multiplication.
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
[jstultz: Reworked one of the checks so it makes more sense]
Signed-off-by: John Stultz <john.stultz@linaro.org>
Diffstat (limited to 'kernel/time/ntp.c')
| -rw-r--r-- | kernel/time/ntp.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c index 149cc8086aea..125fc0342355 100644 --- a/kernel/time/ntp.c +++ b/kernel/time/ntp.c @@ -297,15 +297,17 @@ static void ntp_update_offset(long offset) if (!(time_status & STA_PLL)) return; - if (!(time_status & STA_NANO)) + if (!(time_status & STA_NANO)) { + /* Make sure the multiplication below won't overflow */ + offset = clamp(offset, -USEC_PER_SEC, USEC_PER_SEC); offset *= NSEC_PER_USEC; + } /* * Scale the phase adjustment and * clamp to the operating range. */ - offset = min(offset, MAXPHASE); - offset = max(offset, -MAXPHASE); + offset = clamp(offset, -MAXPHASE, MAXPHASE); /* * Select how the frequency is to be controlled |