re: Input: joydev - validate axis/button maps before clobbering current ones

[Dan Carpenter <dan.carpenter@oracle.com>]

Hello Stephen Kitt,

The patch 999b874f4aa3: "Input: joydev - validate axis/button maps
before clobbering current ones" from Aug 25, 2009, leads to the
following static checker warning:

	drivers/input/joydev.c:466 joydev_handle_JSIOCSAXMAP()
	error: 'abspam' dereferencing possible ERR_PTR()

drivers/input/joydev.c
   437  static int joydev_handle_JSIOCSAXMAP(struct joydev *joydev,
   438                                       void __user *argp, size_t len)
   439  {
   440          __u8 *abspam;
   441          int i;
   442          int retval = 0;
   443  
   444          len = min(len, sizeof(joydev->abspam));
   445  
   446          /* Validate the map. */
   447          abspam = memdup_user(argp, len);
   448          if (IS_ERR(abspam)) {
   449                  retval = PTR_ERR(abspam);
   450                  goto out;

out labels are error prone.  It's safer to return directly.

https://plus.google.com/106378716002406849458/posts/dnanfhQ4mHQ

joydev_handle_JSIOCSBTNMAP() has the same issue.

   451          }
   452  
   453          for (i = 0; i < joydev->nabs; i++) {
   454                  if (abspam[i] > ABS_MAX) {
   455                          retval = -EINVAL;
   456                          goto out;
   457                  }
   458          }
   459  
   460          memcpy(joydev->abspam, abspam, len);
   461  
   462          for (i = 0; i < joydev->nabs; i++)
   463                  joydev->absmap[joydev->abspam[i]] = i;
   464  
   465   out:
   466          kfree(abspam);
   467          return retval;
   468  }

regards,
dan carpenter