Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1199250

Re: [PATCH v3] HID: hid-input: Fix accessing freed memory during device disconnect

Show all headers | View raw

On Mon, Aug 03, 2015 at 02:57:30PM +0900, Krzysztof Kozlowski wrote:
> During unbinding the driver was dereferencing a pointer to memory
> already freed by power_supply_unregister().
> 
> Driver was freeing its internal description of battery through pointers
> stored in power_supply structure. However, because the core owns the
> power supply instance, after calling power_supply_unregister() this
> memory is freed and the driver cannot access these members.
> 
> Fix this by storing the pointer to internal description of battery in a
> local variable before calling power_supply_unregister(), so the pointer
> remains valid.
> 
> Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
> Reported-by: H.J. Lu <hjl.tools@gmail.com>
> Fixes: 297d716f6260 ("power_supply: Change ownership from driver to core")
> Cc: <stable@vger.kernel.org>
> 

FWIW:

Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

> ---
> Changes since v2:
> 1. Add missing 'const'.
> 
> Changes since v1:
> 1. Re-work idea, use local variable instead of devm-like functions
>    (pointed out by Dmitry Torokhov).
> 2. Adjusted subject and commit message.
> ---
>  drivers/hid/hid-input.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c
> index 14aebe483219..53aeaf6252c7 100644
> --- a/drivers/hid/hid-input.c
> +++ b/drivers/hid/hid-input.c
> @@ -462,12 +462,15 @@ out:
>  
>  static void hidinput_cleanup_battery(struct hid_device *dev)
>  {
> +	const struct power_supply_desc *psy_desc;
> +
>  	if (!dev->battery)
>  		return;
>  
> +	psy_desc = dev->battery->desc;
>  	power_supply_unregister(dev->battery);
> -	kfree(dev->battery->desc->name);
> -	kfree(dev->battery->desc);
> +	kfree(psy_desc->name);
> +	kfree(psy_desc);
>  	dev->battery = NULL;
>  }
>  #else  /* !CONFIG_HID_BATTERY_STRENGTH */
> -- 
> 1.9.1
> 

-- 
Dmitry
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCH v3] HID: hid-input: Fix accessing freed memory during device  disconnect Krzysztof Kozlowski <k.kozlowski@samsung.com> - 2015-08-03 08:00 +0200
  Re: [PATCH v3] HID: hid-input: Fix accessing freed memory during  device disconnect Dmitry Torokhov <dmitry.torokhov@gmail.com> - 2015-08-03 22:40 +0200
  Re: [PATCH v3] HID: hid-input: Fix accessing freed memory during  device disconnect Jiri Kosina <jkosina@suse.com> - 2015-08-04 15:50 +0200

csiph-web