From: Sasha Levin <sasha.levin@oracle.com>
Date: Tue, 22 Dec 2015 17:43:36 +0000 (-0500)
Subject: power: test_power: correctly handle empty writes
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=6b9140f39c2aaf76791197fbab0839c0e4af56e8;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git

power: test_power: correctly handle empty writes

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>
---

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';