[PATCH 3.19.y-ckt 166/210] power: test_power: correctly handle empty writes

From: Kamal Mostafa
Date: Thu Jan 28 2016 - 20:37:59 EST


3.19.8-ckt14 -stable review patch. If anyone has any objections, please let me know.

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

From: Sasha Levin <sasha.levin@xxxxxxxxxx>

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@xxxxxxxxxx>
Signed-off-by: Sebastian Reichel <sre@xxxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
---
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 0152f35..b47bd17 100644
--- a/drivers/power/test_power.c
+++ b/drivers/power/test_power.c
@@ -275,6 +275,8 @@ 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