On 2019/7/26 17:06, Charles Keepax wrote:
On Fri, Jul 26, 2019 at 04:48:16PM +0800, Jia-Ju Bai wrote:
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 <baijiaju1990@xxxxxxxxx>
---
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 for the advice.
I will send a v2 patch of adding a new check in wm97xx_init_pen_irq().
Best wishes,
Jia-Ju Bai
