5.4-stable review patch. If anyone has any objections, please let me know.
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From: Ian Abbott abbotti@mev.co.uk
commit ed93c6f68a3be06e4e0c331c6e751f462dee3932 upstream.
When checking for a supported IRQ number, the following test is used:
/* only irqs 2, 3, 4, 5, 6, 7, 10, 11, 12, 14, and 15 are valid */ 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.
Reported-by: syzbot+c52293513298e0fd9a94@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=c52293513298e0fd9a94 Fixes: 729988507680 ("staging: comedi: das16m1: tidy up the irq support in das16m1_attach()") Tested-by: syzbot+c52293513298e0fd9a94@syzkaller.appspotmail.com Suggested-by: "Enju, Kohei" enjuk@amazon.co.jp Cc: stable@vger.kernel.org # 5.13+ Signed-off-by: Ian Abbott abbotti@mev.co.uk Link: https://lore.kernel.org/r/20250707130908.70758-1-abbotti@mev.co.uk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/staging/comedi/drivers/das16m1.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/drivers/staging/comedi/drivers/das16m1.c +++ b/drivers/staging/comedi/drivers/das16m1.c @@ -523,7 +523,8 @@ static int das16m1_attach(struct comedi_ devpriv->extra_iobase = dev->iobase + DAS16M1_8255_IOBASE;
/* only irqs 2, 3, 4, 5, 6, 7, 10, 11, 12, 14, and 15 are valid */ - if ((1 << it->options[1]) & 0xdcfc) { + if (it->options[1] >= 2 && it->options[1] <= 15 && + (1 << it->options[1]) & 0xdcfc) { ret = request_irq(it->options[1], das16m1_interrupt, 0, dev->board_name, dev); if (ret == 0)