From: Sasha Levin <sasha.levin@oracle.com>
To: linux-kernel@vger.kernel.org
Cc: Sasha Levin <sasha.levin@oracle.com>,
John Stultz <john.stultz@linaro.org>,
Thomas Gleixner <tglx@linutronix.de>
Subject: [PATCH] time: adjtimex: validate the ADJ_FREQUENCY case
Date: Wed, 3 Dec 2014 19:25:05 -0500 [thread overview]
Message-ID: <1417652705-1959-1-git-send-email-sasha.levin@oracle.com> (raw)
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.levin@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
next reply other threads:[~2014-12-04 0:25 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-04 0:25 Sasha Levin [this message]
2014-12-04 1:09 ` John Stultz
2014-12-04 2:40 ` Sasha Levin
2014-12-04 4:12 ` John Stultz
2014-12-18 21:23 ` John Stultz
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