When checking for a supported IRQ number, the following test is used:
if ((1 << it->options[1]) & 0xdcfc) {
However, `it->options[i]` is an unchecked `int` value from userspace, so
the shift amount could be negative or out of bounds. Fix the test by
requiring `it->options[1]` to be within bounds before proceeding with
the original test. Valid `it->options[1]` values that select the IRQ
will be in the range [1,15]. The value 0 explicitly disables the use of
interrupts.
Fixes: ad7a370c8be4 ("staging: comedi: aio_iiro_16: add command support for change of state detection")
Cc: <stable@vger.kernel.org> # 5.13+
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
---
Patch does not apply cleanly to longterm kernels 5.4.x and 5.10.x.
---
drivers/comedi/drivers/aio_iiro_16.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/comedi/drivers/aio_iiro_16.c b/drivers/comedi/drivers/aio_iiro_16.c
index b00fab0b89d4..739cc4db52ac 100644
--- a/drivers/comedi/drivers/aio_iiro_16.c
+++ b/drivers/comedi/drivers/aio_iiro_16.c
@@ -177,7 +177,8 @@ static int aio_iiro_16_attach(struct comedi_device *dev,
* Digital input change of state interrupts are optionally supported
* using IRQ 2-7, 10-12, 14, or 15.
*/
- if ((1 << it->options[1]) & 0xdcfc) {
+ if (it->options[1] > 0 && it->options[1] < 16 &&
+ (1 << it->options[1]) & 0xdcfc) {
ret = request_irq(it->options[1], aio_iiro_16_cos, 0,
dev->board_name, dev);
if (ret == 0)
--
2.47.2