[ 3.5.y.z extended stable ] Patch "HID: battery: don't do DMA from stack" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    HID: battery: don't do DMA from stack

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From bcf4652f331ceb7cf3718da66fe8a00cb6f2f469 Mon Sep 17 00:00:00 2001
From: Jiri Kosina <jkosina at suse.cz>
Date: Mon, 2 Sep 2013 13:43:00 +0200
Subject: [PATCH] HID: battery: don't do DMA from stack

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 at alum.mit.edu>
Reported-by: Alan Stern <stern at rowland.harvard.edu>
Signed-off-by: Jiri Kosina <jkosina at suse.cz>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/hid/hid-input.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c
index 73f2f7c..c460b74 100644
--- a/drivers/hid/hid-input.c
+++ b/drivers/hid/hid-input.c
@@ -325,7 +325,7 @@ 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:
@@ -334,12 +334,19 @@ 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;
@@ -349,6 +356,7 @@ 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:
--
1.8.3.2