linux-kernel - Re: NULL pointer dereference in i2c-hid

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Thu, 11 Dec 2014 16:03:07 +0200
From:	Mika Westerberg <mika.westerberg@...ux.intel.com>
To:	Gabriele Mazzotta <gabriele.mzt@...il.com>
Cc:	linux-input@...r.kernel.org, linux-kernel@...r.kernel.org,
	benjamin.tissoires@...hat.com, aduggan@...aptics.com,
	jkosina@...e.cz
Subject: Re: NULL pointer dereference in i2c-hid

On Thu, Dec 11, 2014 at 10:58:01AM +0200, Mika Westerberg wrote:
> On Wed, Dec 10, 2014 at 06:04:51PM +0100, Gabriele Mazzotta wrote:
> > my laptop uses a touchpad that needs hid-rmi along with i2c-hid to work.
> > i2c-hid and hid-rmi can be loaded and unloaded independelty from each
> > other, however since 34f439e4afcd ("HID: i2c-hid: add runtime PM support")
> > if I unload hid-rmi and after it I also unload i2c-hid, I get a NULL
> > pointer dereference.
> 
> I'll look into this.
> 
> I can reproduce this easily with i2c-hid + hid-multitouch following your
> directions.

Can you try the below patch? 

I think we shouldn't free buffers yet in ->stop() because we need the
command buffer sending power commands to the device. Also it seems that
->start() re-allocates buffers anyway if maximum size increases.

It shouldn't even leak memory as we release buffers at ->remove()
anyway.

diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c
index 62cec01937ea..68a8c938feea 100644
--- a/drivers/hid/i2c-hid/i2c-hid.c
+++ b/drivers/hid/i2c-hid/i2c-hid.c
@@ -705,12 +705,7 @@ static int i2c_hid_start(struct hid_device *hid)
 
 static void i2c_hid_stop(struct hid_device *hid)
 {
-	struct i2c_client *client = hid->driver_data;
-	struct i2c_hid *ihid = i2c_get_clientdata(client);
-
 	hid->claimed = 0;
-
-	i2c_hid_free_buffers(ihid);
 }
 
 static int i2c_hid_open(struct hid_device *hid)
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/