[PATCH] commdi: pcl726: Prevent invalid irq number

[Edward Adam Davis]

The reproducer passed in an irq number(0x80008000) that was too large,
which triggered the oob.

Added an interrupt number check to prevent users from passing in an irq
number that was too large.

Fixes: fff46207245c ("staging: comedi: pcl726: enable the interrupt support code")
Reported-by: syzbot+5cd373521edd68bebcb3@xxxxxxxxxxxxxxxxxxxxxxxxx
Closes: https://syzkaller.appspot.com/bug?extid=5cd373521edd68bebcb3
Tested-by: syzbot+5cd373521edd68bebcb3@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Edward Adam Davis <eadavis@xxxxxx>
---
 drivers/comedi/drivers/pcl726.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/comedi/drivers/pcl726.c b/drivers/comedi/drivers/pcl726.c
index 0430630e6ebb..8802f33f1954 100644
--- a/drivers/comedi/drivers/pcl726.c
+++ b/drivers/comedi/drivers/pcl726.c
@@ -328,6 +328,9 @@ static int pcl726_attach(struct comedi_device *dev,
 	 * Hook up the external trigger source interrupt only if the
 	 * user config option is valid and the board supports interrupts.
 	 */
+	if (it->options[1] < 0 || it->options[1] > 31)
+		return -EINVAL;
+
 	if (it->options[1] && (board->irq_mask & (1 << it->options[1]))) {
 		ret = request_irq(it->options[1], pcl726_interrupt, 0,
 				  dev->board_name, dev);
-- 
2.43.0