From b9bf9131b1a44e56d47b63cbb2ccf834d1d64d8c Mon Sep 17 00:00:00 2001
From: Sasha Levin <sasha.levin@oracle.com>
Date: Tue, 22 Dec 2015 12:43:36 -0500
Subject: [PATCH] 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@oracle.com>
Signed-off-by: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
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 83c42ea88f2b..57246cdbd042 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';