On 2012-09-18 01:17, H Hartley Sweeten wrote:
The 'chanlist' in the comedi_cmd struct is an unsigned int __user pointer. The do_cmd_ioctl() and do_cmdtest_ioctl() functions in comedi_fops do a copy_from_user() to move the data from user space to kernel space before passing the comedi_cmd to the comedi drivers. Unfortunately, the drivers then think 'chanlist' is still a __user pointer since thats how the struct is defined. Make the 'chanlist' a union of both a __user and kernel pointer. The do_cmd_*_ioctl() functions are the only ones that use the __user pointer. All the drivers then use the kernel pointer to access the chanlist.
Personally, I'd rather get rid of the __user pointers in comedi.h and do the appropriate casting in the comedi core.
(I came up with a macro a while ago to make the casting less ugly, but I need to test that with `sparse` to make sure it doesn't get confused.)
-- -=( Ian Abbott @ MEV Ltd. E-mail: <abbotti@xxxxxxxxx> )=- -=( Tel: +44 (0)161 477 1898 FAX: +44 (0)161 718 3587 )=- _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/devel
