Verify that the frequency value from userspace is valid and makes sense.
Unverified values can cause overflows later on.
Signed-off-by: Sasha Levin <sasha.le...@oracle.com>
---
kernel/time/ntp.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index 87a346f..54828cf 100644
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -633,6 +633,15 @@ int ntp_validate_timex(struct timex *txc)
if ((txc->modes & ADJ_SETOFFSET) && (!capable(CAP_SYS_TIME)))
return -EPERM;
+ if (txc->modes & ADJ_FREQUENCY) {
+ if (!capable(CAP_SYS_TIME))
+ return -EPERM;
+ if (txc->freq < 0)
+ return -EINVAL;
+ if (LONG_MAX / PPM_SCALE < txc->freq)
+ return -EINVAL;
+ }
+
return 0;
}
--
1.7.10.4
--
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