CVE-2025-38478

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

comedi: Fix initialization of data for instructions that write to subdevice

Some Comedi subdevice instruction handlers are known to access

instruction data elements beyond the first `insn->n` elements in some

cases. The `do_insn_ioctl()` and `do_insnlist_ioctl()` functions

allocate at least `MIN_SAMPLES` (16) data elements to deal with this,

but they do not initialize all of that. For Comedi instruction codes

that write to the subdevice, the first `insn->n` data elements are

copied from user-space, but the remaining elements are left

uninitialized. That could be a problem if the subdevice instruction

handler reads the uninitialized data. Ensure that the first

`MIN_SAMPLES` elements are initialized before calling these instruction

handlers, filling the uncopied elements with 0. For

`do_insnlist_ioctl()`, the same data buffer elements are used for

handling a list of instructions, so ensure the first `MIN_SAMPLES`

elements are initialized for each instruction that writes to the

subdevice.