| From | Luis Henriques <> | Subject | [PATCH 3.16.y-ckt 132/183] time: adjtimex: Validate the ADJ_FREQUENCY values | Date | Fri, 6 Mar 2015 09:57:03 +0000 |
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3.16.7-ckt8 -stable review patch. If anyone has any objections, please let me know.
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From: Sasha Levin <sasha.levin@oracle.com>
commit 5e5aeb4367b450a28f447f6d5ab57d8f2ab16a5f upstream.
Verify that the frequency value from userspace is valid and makes sense.
Unverified values can cause overflows later on.
Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com> [jstultz: Fix up bug for negative values and drop redunent cap check] Signed-off-by: John Stultz <john.stultz@linaro.org> Signed-off-by: Luis Henriques <luis.henriques@canonical.com> --- kernel/time/ntp.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c index 33db43a39515..3fca3fdd7c82 100644 --- a/kernel/time/ntp.c +++ b/kernel/time/ntp.c @@ -632,6 +632,13 @@ int ntp_validate_timex(struct timex *txc) if ((txc->modes & ADJ_SETOFFSET) && (!capable(CAP_SYS_TIME))) return -EPERM; + if (txc->modes & ADJ_FREQUENCY) { + if (LONG_MIN / PPM_SCALE > txc->freq) + return -EINVAL; + if (LONG_MAX / PPM_SCALE < txc->freq) + return -EINVAL; + } + return 0; }
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