HID: battery: don't do DMA from stack

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

Cc: stable@kernel.org
Reported-by: Richard Ryniker <ryniker@alum.mit.edu>
Reported-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

1 files changed, 10 insertions, 2 deletions

diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c
index 7480799e535c..3fc4034a4367 100644
--- a/drivers/hid/hid-input.c
+++ b/drivers/hid/hid-input.c
@@ -340,7 +340,7 @@ static int hidinput_get_battery_property(struct power_supply *psy,
 {
         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:
@@ -349,12 +349,19 @@ static int hidinput_get_battery_property(struct power_supply *psy,
                 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) {
                         ret = -ENODATA;
+                        kfree(buf);
                         break;
                 }
                 ret = 0;
@@ -364,6 +371,7 @@ static int hidinput_get_battery_property(struct power_supply *psy,
                     buf[1] <= dev->battery_max)
                         val->intval = (100 * (buf[1] - dev->battery_min)) /
                                 (dev->battery_max - dev->battery_min);
+                kfree(buf);
                 break;
 
         case POWER_SUPPLY_PROP_MODEL_NAME: