Re: [PATCH] Input: uinput - handle compat ioctl for UI_SET_PHYS
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From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Date: 2016-05-20 16:32:16
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Hi Ricky, On Tue, May 17, 2016 at 11:39:45PM +0800, Ricky Liang wrote:
quoted hunk ↗ jump to hunk
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 <redacted> --- 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