On Mon, Oct 16, 2017 at 04:14:43PM -0700, Kees Cook wrote:
> In preparation for unconditionally passing the struct timer_list pointer to
> all timer callbacks, switch to using the new timer_setup() and from_timer()
> to pass the timer pointer explicitly.
>
> One input_dev user hijacks the input_dev software autorepeat timer to
> perform its own repeat management. However, there is no path back to the
> existing status variable, so add a generic one to the input structure and
> use that instead.
That is too bad and it should not be doing this. I'd rather av7110 used
its own private timer for that.
>
> Cc: Dmitry Torokhov <dmitry.torok...@gmail.com>
> Cc: Mauro Carvalho Chehab <mche...@kernel.org>
> Cc: Hans Verkuil <hans.verk...@cisco.com>
> Cc: Sakari Ailus <sakari.ai...@linux.intel.com>
> Cc: Geliang Tang <geliangt...@gmail.com>
> Cc: linux-in...@vger.kernel.org
> Cc: linux-media@vger.kernel.org
> Signed-off-by: Kees Cook <keesc...@chromium.org>
> Acked-by: Pali Rohár <pali.ro...@gmail.com>
> ---
> drivers/input/input.c | 12 ++++++------
> drivers/media/pci/ttpci/av7110.h | 1 -
> drivers/media/pci/ttpci/av7110_ir.c | 16 ++++++++--------
> include/linux/input.h | 2 ++
> 4 files changed, 16 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/input/input.c b/drivers/input/input.c
> index d268fdc23c64..497ad2dcb699 100644
> --- a/drivers/input/input.c
> +++ b/drivers/input/input.c
> @@ -76,7 +76,7 @@ static void input_start_autorepeat(struct input_dev *dev,
> int code)
> {
> if (test_bit(EV_REP, dev->evbit) &&
> dev->rep[REP_PERIOD] && dev->rep[REP_DELAY] &&
> - dev->timer.data) {
> + dev->timer.function) {
> dev->repeat_key = code;
> mod_timer(&dev->timer,
> jiffies + msecs_to_jiffies(dev->rep[REP_DELAY]));
> @@ -179,9 +179,9 @@ static void input_pass_event(struct input_dev *dev,
> * dev->event_lock here to avoid racing with input_event
> * which may cause keys get "stuck".
> */
> -static void input_repeat_key(unsigned long data)
> +static void input_repeat_key(struct timer_list *t)
> {
> - struct input_dev *dev = (void *) data;
> + struct input_dev *dev = from_timer(dev, t, timer);
> unsigned long flags;
>
> spin_lock_irqsave(&dev->event_lock, flags);
> @@ -1790,7 +1790,7 @@ struct input_dev *input_allocate_device(void)
> device_initialize(&dev->dev);
> mutex_init(&dev->mutex);
> spin_lock_init(&dev->event_lock);
> - init_timer(&dev->timer);
> + timer_setup(&dev->timer, NULL, 0);
> INIT_LIST_HEAD(&dev->h_list);
> INIT_LIST_HEAD(&dev->node);
>
> @@ -2053,8 +2053,8 @@ static void devm_input_device_unregister(struct device
> *dev, void *res)
> */
> void input_enable_softrepeat(struct input_dev *dev, int delay, int period)
> {
> - dev->timer.data = (unsigned long) dev;
> - dev->timer.function = input_repeat_key;
> + dev->timer.function = (TIMER_FUNC_TYPE)input_repeat_key;
> + dev->timer_data = 0;
> dev->rep[REP_DELAY] = delay;
> dev->rep[REP_PERIOD] = period;
> }
> diff --git a/drivers/media/pci/ttpci/av7110.h
> b/drivers/media/pci/ttpci/av7110.h
> index 347827925c14..b98a4f3006df 100644
> --- a/drivers/media/pci/ttpci/av7110.h
> +++ b/drivers/media/pci/ttpci/av7110.h
> @@ -93,7 +93,6 @@ struct infrared {
> u8 inversion;
> u16 last_key;
> u16 last_toggle;
> - u8 delay_timer_finished;
> };
>
>
> diff --git a/drivers/media/pci/ttpci/av7110_ir.c
> b/drivers/media/pci/ttpci/av7110_ir.c
> index ca05198de2c2..a883caa6488c 100644
> --- a/drivers/media/pci/ttpci/av7110_ir.c
> +++ b/drivers/media/pci/ttpci/av7110_ir.c
> @@ -155,16 +155,16 @@ static void av7110_emit_key(unsigned long parm)
> if (timer_pending(&ir->keyup_timer)) {
> del_timer(&ir->keyup_timer);
> if (ir->last_key != keycode || toggle != ir->last_toggle) {
> - ir->delay_timer_finished = 0;
> + ir->input_dev->timer_data = 0;
> input_event(ir->input_dev, EV_KEY, ir->last_key, 0);
> input_event(ir->input_dev, EV_KEY, keycode, 1);
> input_sync(ir->input_dev);
> - } else if (ir->delay_timer_finished) {
> + } else if (ir->input_dev->timer_data) {
> input_event(ir->input_dev, EV_KEY, keycode, 2);
> input_sync(ir->input_dev);
> }
> } else {
> - ir->delay_timer_finished = 0;
> + ir->input_dev->timer_data = 0;
> input_event(ir->input_dev, EV_KEY, keycode, 1);
> input_sync(ir->input_dev);
> }
> @@ -206,11 +206,12 @@ static void input_register_keys(struct infrared *ir)
>
>
> /* called by the input driver after rep[REP_DELAY] ms */
> -static void input_repeat_key(unsigned long parm)
> +static void input_repeat_key(struct timer_list *t)
> {
> - struct infrared *ir = (struct infrared *) parm;
> + struct input_dev *dev = from_timer(dev, t, timer);
>
> - ir->delay_timer_finished = 1;
> + /* Key repeat started */
> + dev->timer_data = 1;
> }
>
>
> @@ -365,8 +366,7 @@ int av7110_ir_init(struct av7110 *av7110)
> input_free_device(input_dev);
> return err;
> }
> - input_dev->timer.function = input_repeat_key;
> - input_dev->timer.data = (unsigned long) &av7110->ir;
> + input_dev->timer.function = (TIMER_FUNC_TYPE)input_repeat_key;
>
> if (av_cnt == 1) {
> e = proc_create("av7110_ir", S_IWUSR, NULL,
> &av7110_ir_proc_fops);
> diff --git a/include/linux/input.h b/include/linux/input.h
> index fb5e23c7ed98..dcd117bf1027 100644
> --- a/include/linux/input.h
> +++ b/include/linux/input.h
> @@ -70,6 +70,7 @@ struct input_value {
> * @repeat_key: stores key code of the last key pressed; used to implement
> * software autorepeat
> * @timer: timer for software autorepeat
> + * @timer_data: timer data for software autorepeat overrides
> * @rep: current values for autorepeat parameters (delay, rate)
> * @mt: pointer to multitouch state
> * @absinfo: array of &struct input_absinfo elements holding information
> @@ -152,6 +153,7 @@ struct input_dev {
>
> unsigned int repeat_key;
> struct timer_list timer;
> + unsigned long timer_data;
>
> int rep[REP_CNT];
>
> --
> 2.7.4
>
>
> --
> Kees Cook
> Pixel Security
--
Dmitry
