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

The "comedi_parport" driver treats a standard printer parallel port as a
COMEDI digital I/O device, driving the port's I/O registers directly.
It uses an admin-supplied configuration option (`it->options[0]`) to
configure the I/O port base address of the device.  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/20260130170416.49994-11-abbotti@mev.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/comedi/drivers/comedi_parport.c b/drivers/comedi/drivers/comedi_parport.c
index 098738a688fe641f64ba86e2441304b3fe550249..2604680d86c4a380c2141aff06e6a1bd0451a7f6 100644 (file)
--- a/drivers/comedi/drivers/comedi_parport.c
+++ b/drivers/comedi/drivers/comedi_parport.c
@@ -225,9 +225,11 @@ static int parport_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;