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authorSasha Levin <sasha.levin@oracle.com>2014-12-03 19:25:05 -0500
committerJohn Stultz <john.stultz@linaro.org>2015-01-07 09:50:32 -0800
commit5e5aeb4367b450a28f447f6d5ab57d8f2ab16a5f (patch)
tree13c92234f198f0cc9147b65f4d90bcb15018f9e9 /kernel/time/ntp.c
parent6ada1fc0e1c4775de0e043e1bd3ae9d065491aa5 (diff)
downloadlinux-5e5aeb4367b450a28f447f6d5ab57d8f2ab16a5f.tar.bz2
time: adjtimex: Validate the ADJ_FREQUENCY values
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> 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>
Diffstat (limited to 'kernel/time/ntp.c')
-rw-r--r--kernel/time/ntp.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index 87a346fd6d61..28bf91c60a0b 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;
}