Evolution-X-Devices/kernel_xiaomi_garnet
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comedi: pcl812: Fix bit shift out of bounds

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commit b14b076ce593f72585412fc7fd3747e03a5e3632 upstream.

When checking for a supported IRQ number, the following test is used:

	if ((1 << it->options[1]) & board->irq_bits) {

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.

Reported-by: syzbot+32de323b0addb9e114ff@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=32de323b0addb9e114ff
Fixes: fcdb427bc7 ("Staging: comedi: add pcl821 driver")
Cc: stable@vger.kernel.org # 5.13+
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Link: https://lore.kernel.org/r/20250707133429.73202-1-abbotti@mev.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ian Abbott
2025-07-07 14:34:29 +01:00
committed by Greg Kroah-Hartman
parent 8ab8589ed2
commit 0489c30d08
1 changed files with 2 additions and 1 deletions
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3
drivers/staging/comedi/drivers/pcl812.c
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@@ -1151,7 +1151,8 @@ static int pcl812_attach(struct comedi_device *dev, struct comedi_devconfig *it)
if (!dev->pacer)
return -ENOMEM;
if ((1 << it->options[1]) & board->irq_bits) {
if (it->options[1] > 0 && it->options[1] < 16 &&
(1 << it->options[1]) & board->irq_bits) {
ret = request_irq(it->options[1], pcl812_interrupt, 0,
dev->board_name, dev);
if (ret == 0)