Messages in this thread | | | Date | Fri, 20 May 2016 09:32:10 -0700 | From | Dmitry Torokhov <> | Subject | Re: [PATCH] Input: uinput - handle compat ioctl for UI_SET_PHYS |
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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 <jcliang@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
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