| From | Ben Hutchings <> | Date | Tue, 17 Feb 2015 01:46:53 +0000 | Subject | [PATCH 3.2 090/152] time: adjtimex: Validate the ADJ_FREQUENCY values |
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3.2.67-rc1 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> [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- kernel/time/ntp.c | 7 +++++++ 1 file changed, 7 insertions(+)
--- a/kernel/time/ntp.c +++ b/kernel/time/ntp.c @@ -608,6 +608,13 @@ int do_adjtimex(struct timex *txc) return -EINVAL; } + if (txc->modes & ADJ_FREQUENCY) { + if (LONG_MIN / PPM_SCALE > txc->freq) + return -EINVAL; + if (LONG_MAX / PPM_SCALE < txc->freq) + return -EINVAL; + } + if (txc->modes & ADJ_SETOFFSET) { struct timespec delta; delta.tv_sec = txc->time.tv_sec;
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