[ 26/40] HID: battery: dont do DMA from stack

Greg Kroah-Hartman
2013-09-25T00:12:39Z

From: Jiri Kosina <jkosina@suse.cz>

commit 6c2794a2984f4c17a58117a68703cc7640f01c5a upstream.

Instead of using data from stack for DMA in hidinput_get_battery_property(),
allocate the buffer dynamically.

Reported-by: Richard Ryniker <ryniker@alum.mit.edu>
Reported-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/hid/hid-input.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)

--- a/drivers/hid/hid-input.c
+++ b/drivers/hid/hid-input.c
@@ -314,7 +314,7 @@ static int hidinput_get_battery_property
{
struct hid_device *dev = container_of(psy, struct hid_device, battery);
int ret = 0;
- __u8 buf[2] = {};
+ __u8 *buf;

switch (prop) {
case POWER_SUPPLY_PROP_PRESENT:
@@ -323,13 +323,20 @@ static int hidinput_get_battery_property
break;

case POWER_SUPPLY_PROP_CAPACITY:
+
+ buf = kmalloc(2 * sizeof(__u8), GFP_KERNEL);
+ if (!buf) {
+ ret = -ENOMEM;
+ break;
+ }
ret = dev->hid_get_raw_report(dev, dev->battery_report_id,
- buf, sizeof(buf),
+ buf, 2,
dev->battery_report_type);

if (ret != 2) {
if (ret >= 0)
ret = -EINVAL;
+ kfree(buf);
break;
}

@@ -338,6 +345,7 @@ static int hidinput_get_battery_property
buf[1] <= dev->battery_max)
val->intval = (100 * (buf[1] - dev->battery_min)) /
(dev->battery_max - dev->battery_min);
+ kfree(buf);
break;