CVE-2025-38529

In the Linux kernel, the following vulnerability has been resolved:

comedi: aio_iiro_16: Fix bit shift out of bounds

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.