re: Input: gamecon - use parallel port device model

re: Input: gamecon - use parallel port device model

[Dan Carpenter]

Hello Sudip Mukherjee,

The patch a517e87c3dfc: "Input: gamecon - use parallel port device
model" from Sep 29, 2015, leads to the following static checker
warning:

	drivers/input/joystick/gamecon.c:988 gc_attach()
	error: buffer overflow 'gc_base' 3 <= 5

drivers/input/joystick/gamecon.c
   972  
   973          for (i = 0; i < n_pads && i < GC_MAX_DEVICES; i++) {
                                              ^^^^^^^^^^^^^^
Should this be GC_MAX_PORTS?

   974                  if (!pads[i])
   975                          continue;
   976  
   977                  if (gc_setup_pad(gc, i, pads[i]))
   978                          goto err_unreg_devs;
   979  
   980                  count++;
   981          }
   982  
   983          if (count == 0) {
   984                  pr_err("No valid devices specified\n");
   985                  goto err_free_gc;
   986          }
   987  
   988          gc_base[i] = gc;
                ^^^^^^^^^^
It's saying this is out of bounds.

Even if we change GC_MAX_DEVICES to GC_MAX_PORTS it will still complain
because we are relying on n_pads to be less than GC_MAX_DEVICES.  I
guess we could change the other condition to be:

	if (count == 0 || i == GC_MAX_PORTS)
		goto err_free_gc;

   989          return;
   990  

regards,
dan carpenter

Re: Input: gamecon - use parallel port device model

[Sudip Mukherjee]

On Fri, Oct 02, 2015 at 01:05:32AM +0300, Dan Carpenter wrote:
> Hello Sudip Mukherjee,
> 
> The patch a517e87c3dfc: "Input: gamecon - use parallel port device
> model" from Sep 29, 2015, leads to the following static checker
> warning:
> 
> 	drivers/input/joystick/gamecon.c:988 gc_attach()
> 	error: buffer overflow 'gc_base' 3 <= 5
> 
> drivers/input/joystick/gamecon.c
>    972  
>    973          for (i = 0; i < n_pads && i < GC_MAX_DEVICES; i++) {
>                                               ^^^^^^^^^^^^^^
Thanks Dan. This would have been an ugly mess. I checked my othher
patches and looks like they will also have the same mistake. I will send
the patch to fix this rightaway.

Thanks again.

regards
sudip