comedi: c6xdigio: Add sanity checks for I/O base address

The "c6xdigio" driver uses an admin-supplied configuration option
(`it->options[0]`) to configure the I/O port base address of a supported
C6x_DIGIO DSP device connected to a PC printer parallel port (driving
the port's I/O registers directly).  Currently, the driver allows any
I/O base address to be specified as long as the I/O region can be
reserved, and it converts the specified `int` option value holding the
base address to `unsigned long`.

It doesn't make sense to allow base addresses that are not aligned to
4-byte boundaries (for SPP printer ports, although printer ports with
EPP/ECP support actually need to be aligned on 8-byte boundaries), so
add a check for 4-byte alignment.

Convert the option value that specifies the base address from `int` to
`unsigned int` instead of `unsigned long` so it ends up the same on
32-bit and 64-bit systems.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Link: https://patch.msgid.link/20260130170416.49994-10-abbotti@mev.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/comedi/drivers/c6xdigio.c b/drivers/comedi/drivers/c6xdigio.c
index 8a38d97d463b2eade0faabe951cd297545516569..b6563a48ada6d60e7c6182f796e4af444da3f65a 100644 (file)
--- a/drivers/comedi/drivers/c6xdigio.c
+++ b/drivers/comedi/drivers/c6xdigio.c
@@ -239,9 +239,11 @@ static int c6xdigio_attach(struct comedi_device *dev,
                           struct comedi_devconfig *it)
 {
        struct comedi_subdevice *s;
+       unsigned int iobase = it->options[0];
        int ret;
 
-       ret = comedi_request_region(dev, it->options[0], 0x03);
+       ret = comedi_check_request_region(dev, iobase, 0x03,
+                                         0, UINT_MAX, 4);
        if (ret)
                return ret;