Hi Ricky,
On Tue, May 17, 2016 at 11:39:45PM +0800, Ricky Liang wrote:
> When running a 32-bit userspace on a 64-bit kernel, the UI_SET_PHYS
> ioctl needs to be treated with special care, as it has the pointer
> size encoded in the command.
>
> Signed-off-by: Ricky Liang <jcli...@chromium.org>
> ---
> drivers/input/misc/uinput.c | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/drivers/input/misc/uinput.c b/drivers/input/misc/uinput.c
> index abe1a92..b4d1b1d 100644
> --- a/drivers/input/misc/uinput.c
> +++ b/drivers/input/misc/uinput.c
> @@ -984,6 +984,15 @@ static long uinput_ioctl(struct file *file, unsigned int
> cmd, unsigned long arg)
> static long uinput_compat_ioctl(struct file *file,
> unsigned int cmd, unsigned long arg)
> {
> + switch (_IOC_NR(cmd)) {
> + case _IOC_NR(UI_SET_PHYS):
> + if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
> + cmd &= ~IOCSIZE_MASK;
> + cmd |= sizeof(void *) << IOCSIZE_SHIFT;
> + }
> + break;
> + }
> +
This looks quite complicated... Can we do this:
#define UI_SET_PHYS_COMPAT __IOW(UINPUT_IOCTL_BASE, 108, compat_uptr_t)
...
if (cmd == UI_SET_PHYS_COMPAT)
cmd = UI_SET_PHYS;
> return uinput_ioctl_handler(file, cmd, arg, compat_ptr(arg));
> }
> #endif
We can use the local define instead of manipulating cmd size because we
will never going to change UI_SET_PHYS definition, since it is part of
uapi.
Thanks.
--
Dmitry
