Re: [PATCH] input: touchscreen: wm97xx-core: Fix possible null-pointer dereferences in wm97xx_ts_input_open()
From: Charles Keepax <ckeepax@opensource.cirrus.com>
Date: 2019-07-26 09:06:49
Also in:
lkml
On Fri, Jul 26, 2019 at 04:48:16PM +0800, Jia-Ju Bai wrote:
quoted hunk ↗ jump to hunk
In wm97xx_ts_input_open(), there is an if statement on line 507 to check whether wm->mach_ops is NULL: if (wm->mach_ops && wm->mach_ops->acc_enabled) When wm->mach_ops is NULL, it is used on line 521: wm97xx_init_pen_irq(wm); BUG_ON(!wm->mach_ops->irq_enable); BUG_ON(!wm->mach_ops->irq_gpio); wm97xx_reg_write(..., reg & ~(wm->mach_ops->irq_gpio)) Thus, possible null-pointer dereferences may occur. To fix these bugs, wm->mach_ops is checked before calling wm97xx_init_pen_irq(). These bugs found by a static analysis tool STCheck written by us. Signed-off-by: Jia-Ju Bai <redacted> --- drivers/input/touchscreen/wm97xx-core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)diff --git a/drivers/input/touchscreen/wm97xx-core.c b/drivers/input/touchscreen/wm97xx-core.c index 0a174bd82915..f7bd0726a577 100644 --- a/drivers/input/touchscreen/wm97xx-core.c +++ b/drivers/input/touchscreen/wm97xx-core.c@@ -517,7 +517,7 @@ static int wm97xx_ts_input_open(struct input_dev *idev) wm->ts_reader_interval = wm->ts_reader_min_interval; wm->pen_is_down = 0; - if (wm->pen_irq) + if (wm->pen_irq && wm->mach_ops) wm97xx_init_pen_irq(wm); else dev_err(wm->dev, "No IRQ specified\n");
This doesn't quite feel like the right fix as it would print an error message saying "No IRQ specified", in the case the IRQ is specified but the mach_ops have not been set. I would suggest either extending the existing BUG_ON or adding a new check in wm97xx_init_pen_irq. Thanks, Charles
-- 2.17.0