* [PATCH v3] HID: hid-input: Fix accessing freed memory during device disconnect
@ 2015-08-03 5:57 Krzysztof Kozlowski
2015-08-03 20:31 ` Dmitry Torokhov
2015-08-04 13:47 ` Jiri Kosina
0 siblings, 2 replies; 3+ messages in thread
From: Krzysztof Kozlowski @ 2015-08-03 5:57 UTC (permalink / raw)
To: Jiri Kosina, linux-input, linux-kernel
Cc: Dmitry Torokhov, sre, linux-pm, H.J. Lu, Krzysztof Kozlowski, stable
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>
---
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
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v3] HID: hid-input: Fix accessing freed memory during device disconnect
2015-08-03 5:57 [PATCH v3] HID: hid-input: Fix accessing freed memory during device disconnect Krzysztof Kozlowski
@ 2015-08-03 20:31 ` Dmitry Torokhov
2015-08-04 13:47 ` Jiri Kosina
1 sibling, 0 replies; 3+ messages in thread
From: Dmitry Torokhov @ 2015-08-03 20:31 UTC (permalink / raw)
To: Krzysztof Kozlowski
Cc: Jiri Kosina, linux-input, linux-kernel, sre, linux-pm, H.J. Lu, stable
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
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v3] HID: hid-input: Fix accessing freed memory during device disconnect
2015-08-03 5:57 [PATCH v3] HID: hid-input: Fix accessing freed memory during device disconnect Krzysztof Kozlowski
2015-08-03 20:31 ` Dmitry Torokhov
@ 2015-08-04 13:47 ` Jiri Kosina
1 sibling, 0 replies; 3+ messages in thread
From: Jiri Kosina @ 2015-08-04 13:47 UTC (permalink / raw)
To: Krzysztof Kozlowski
Cc: linux-input, linux-kernel, Dmitry Torokhov, sre, linux-pm,
H.J. Lu, stable
On Mon, 3 Aug 2015, 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>
Applied to for-4.2/upstream-fixes-devm-fixed, and thanks again Dmitry for
catching my mistake.
--
Jiri Kosina
SUSE Labs
^ permalink raw reply [flat|nested] 3+ messages in thread
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2015-08-04 13:47 ` Jiri Kosina
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