[3.16.y-ckt stable] Patch "time: adjtimex: Validate the ADJ_FREQUENCY values" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    time: adjtimex: Validate the ADJ_FREQUENCY values

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt6.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From e18034cee3c5aaf021dedb9f7b3fbf280daf50ef Mon Sep 17 00:00:00 2001
From: Sasha Levin <sasha.levin at oracle.com>
Date: Wed, 3 Dec 2014 19:25:05 -0500
Subject: time: adjtimex: Validate the ADJ_FREQUENCY values

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 at linutronix.de>
Cc: Ingo Molnar <mingo at kernel.org>
Signed-off-by: Sasha Levin <sasha.levin at oracle.com>
[jstultz: Fix up bug for negative values and drop redunent cap check]
Signed-off-by: John Stultz <john.stultz at linaro.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 kernel/time/ntp.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index 33db43a39515..3fca3fdd7c82 100644
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -632,6 +632,13 @@ 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;
 }

--
2.1.4