Messages in this thread Patch in this message | | | From | John Stultz <> | Subject | [PATCH 2/2] time: adjtimex: Validate the ADJ_FREQUENCY values | Date | Wed, 7 Jan 2015 10:12:20 -0800 |
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From: Sasha Levin <sasha.levin@oracle.com>
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> Cc: stable <stable@vger.kernel.org> Cc: Andy Lutomirski <luto@amacapital.net> 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> --- kernel/time/ntp.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c index 87a346f..28bf91c 100644 --- a/kernel/time/ntp.c +++ b/kernel/time/ntp.c @@ -633,6 +633,13 @@ 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; } -- 1.9.1
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