linux-stable/sound/core/hwdep_compat.c
Arnd Bergmann 18d122c028 ALSA: compat_ioctl: avoid compat_alloc_user_space
Using compat_alloc_user_space() tends to add complexity
to the ioctl handling, so I am trying to remove it everywhere.

The two callers in sound/core can rewritten to just call
the same code that operates on a kernel pointer as the
native handler.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20200918095642.1446243-1-arnd@arndb.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2020-09-21 10:37:07 +02:00

55 lines
1.4 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* 32bit -> 64bit ioctl wrapper for hwdep API
* Copyright (c) by Takashi Iwai <tiwai@suse.de>
*/
/* This file is included from hwdep.c */
#include <linux/compat.h>
struct snd_hwdep_dsp_image32 {
u32 index;
unsigned char name[64];
u32 image; /* pointer */
u32 length;
u32 driver_data;
} /* don't set packed attribute here */;
static int snd_hwdep_dsp_load_compat(struct snd_hwdep *hw,
struct snd_hwdep_dsp_image32 __user *src)
{
struct snd_hwdep_dsp_image info = {};
compat_caddr_t ptr;
if (copy_from_user(&info, src, 4 + 64) ||
get_user(ptr, &src->image) ||
get_user(info.length, &src->length) ||
get_user(info.driver_data, &src->driver_data))
return -EFAULT;
info.image = compat_ptr(ptr);
return snd_hwdep_dsp_load(hw, &info);
}
enum {
SNDRV_HWDEP_IOCTL_DSP_LOAD32 = _IOW('H', 0x03, struct snd_hwdep_dsp_image32)
};
static long snd_hwdep_ioctl_compat(struct file * file, unsigned int cmd,
unsigned long arg)
{
struct snd_hwdep *hw = file->private_data;
void __user *argp = compat_ptr(arg);
switch (cmd) {
case SNDRV_HWDEP_IOCTL_PVERSION:
case SNDRV_HWDEP_IOCTL_INFO:
case SNDRV_HWDEP_IOCTL_DSP_STATUS:
return snd_hwdep_ioctl(file, cmd, (unsigned long)argp);
case SNDRV_HWDEP_IOCTL_DSP_LOAD32:
return snd_hwdep_dsp_load_compat(hw, argp);
}
if (hw->ops.ioctl_compat)
return hw->ops.ioctl_compat(hw, file, cmd, arg);
return -ENOIOCTLCMD;
}