[4.2.y-ckt stable] Patch "power: test_power: correctly handle empty writes" has been added to the 4.2.y-ckt tree

[Kamal Mostafa]

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

    power: test_power: correctly handle empty writes

to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue

This patch is scheduled to be released in version 4.2.8-ckt3.

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

For more information about the 4.2.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

---8<------------------------------------------------------------

>From cdabb7f2a051c5c4a9374be672eab562790f69de Mon Sep 17 00:00:00 2001
From: Sasha Levin <sasha.levin at oracle.com>
Date: Tue, 22 Dec 2015 12:43:36 -0500
Subject: power: test_power: correctly handle empty writes

commit 6b9140f39c2aaf76791197fbab0839c0e4af56e8 upstream.

Writing 0 length data into test_power makes it access an invalid array
location and kill the system.

Fixes: f17ef9b2d ("power: Make test_power driver more dynamic.")
Signed-off-by: Sasha Levin <sasha.levin at oracle.com>
Signed-off-by: Sebastian Reichel <sre at kernel.org>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/power/test_power.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/power/test_power.c b/drivers/power/test_power.c
index 83c42ea..57246cd 100644
--- a/drivers/power/test_power.c
+++ b/drivers/power/test_power.c
@@ -301,6 +301,8 @@ static int map_get_value(struct battery_property_map *map, const char *key,
 	buf[MAX_KEYLENGTH-1] = '\0';

 	cr = strnlen(buf, MAX_KEYLENGTH) - 1;
+	if (cr < 0)
+		return def_val;
 	if (buf[cr] == '\n')
 		buf[cr] = '\0';

--
1.9.1