When checking for a supported IRQ number, the following test is used:
/* IRQs 2,3,5,6,7, 10,11,15 are valid for "enhanced" mode */ if ((1 << it->options[1]) & 0x8cec) {
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: 79e5e6addbb1 ("staging: comedi: das6402: rewrite broken driver") 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/das6402.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/comedi/drivers/das6402.c b/drivers/comedi/drivers/das6402.c index 68f95330de45..7660487e563c 100644 --- a/drivers/comedi/drivers/das6402.c +++ b/drivers/comedi/drivers/das6402.c @@ -567,7 +567,8 @@ static int das6402_attach(struct comedi_device *dev, das6402_reset(dev);
/* IRQs 2,3,5,6,7, 10,11,15 are valid for "enhanced" mode */ - if ((1 << it->options[1]) & 0x8cec) { + if (it->options[1] > 0 && it->options[1] < 16 && + (1 << it->options[1]) & 0x8cec) { ret = request_irq(it->options[1], das6402_interrupt, 0, dev->board_name, dev); if (ret == 0) {