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linux/sound/core/control_compat.c
Takashi Iwai 471be437be ALSA: control: Use guard() for locking 
We can simplify the code gracefully with new guard() macro and co for
automatic cleanup of locks.

The lops calls under multiple rwsems are factored out as a simple
macro, so that it can be called easily from snd_ctl_dev_register()
and snd_ctl_dev_disconnect().

There are a few remaining explicit rwsem and spinlock calls, and those
are the places where the lock downgrade happens or where the temporary
unlock/relocking happens -- which guard() doens't cover well yet.

Only the code refactoring, and no functional changes.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://lore.kernel.org/r/20240227085306.9764-9-tiwai@suse.de
2024-02-28 15:01:21 +01:00

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* compat ioctls for control API
*
* Copyright (c) by Takashi Iwai <tiwai@suse.de>
*/
/* this file included from control.c */
#include <linux/compat.h>
#include <linux/slab.h>
struct snd_ctl_elem_list32 {
u32 offset;
u32 space;
u32 used;
u32 count;
u32 pids;
unsigned char reserved[50];
} /* don't set packed attribute here */;
static int snd_ctl_elem_list_compat(struct snd_card *card,
struct snd_ctl_elem_list32 __user *data32)
{
struct snd_ctl_elem_list data = {};
compat_caddr_t ptr;
int err;
/* offset, space, used, count */
if (copy_from_user(&data, data32, 4 * sizeof(u32)))
return -EFAULT;
/* pids */
if (get_user(ptr, &data32->pids))
return -EFAULT;
data.pids = compat_ptr(ptr);
err = snd_ctl_elem_list(card, &data);
if (err < 0)
return err;
/* copy the result */
if (copy_to_user(data32, &data, 4 * sizeof(u32)))
return -EFAULT;
return 0;
}
/*
* control element info
* it uses union, so the things are not easy..
*/
struct snd_ctl_elem_info32 {
struct snd_ctl_elem_id id; // the size of struct is same
s32 type;
u32 access;
u32 count;
s32 owner;
union {
struct {
s32 min;
s32 max;
s32 step;
} integer;
struct {
u64 min;
u64 max;
u64 step;
} integer64;
struct {
u32 items;
u32 item;
char name[64];
u64 names_ptr;
u32 names_length;
} enumerated;
unsigned char reserved[128];
} value;
unsigned char reserved[64];
} __packed;
static int snd_ctl_elem_info_compat(struct snd_ctl_file *ctl,
struct snd_ctl_elem_info32 __user *data32)
{
struct snd_ctl_elem_info *data __free(kfree) = NULL;
int err;
data = kzalloc(sizeof(*data), GFP_KERNEL);
if (! data)
return -ENOMEM;
/* copy id */
if (copy_from_user(&data->id, &data32->id, sizeof(data->id)))
return -EFAULT;
/* we need to copy the item index.
* hope this doesn't break anything..
*/
if (get_user(data->value.enumerated.item, &data32->value.enumerated.item))
return -EFAULT;
err = snd_ctl_elem_info(ctl, data);
if (err < 0)
return err;
/* restore info to 32bit */
/* id, type, access, count */
if (copy_to_user(&data32->id, &data->id, sizeof(data->id)) ||
copy_to_user(&data32->type, &data->type, 3 * sizeof(u32)))
return -EFAULT;
if (put_user(data->owner, &data32->owner))
return -EFAULT;
switch (data->type) {
case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
case SNDRV_CTL_ELEM_TYPE_INTEGER:
if (put_user(data->value.integer.min, &data32->value.integer.min) ||
put_user(data->value.integer.max, &data32->value.integer.max) ||
put_user(data->value.integer.step, &data32->value.integer.step))
return -EFAULT;
break;
case SNDRV_CTL_ELEM_TYPE_INTEGER64:
if (copy_to_user(&data32->value.integer64,
&data->value.integer64,
sizeof(data->value.integer64)))
return -EFAULT;
break;
case SNDRV_CTL_ELEM_TYPE_ENUMERATED:
if (copy_to_user(&data32->value.enumerated,
&data->value.enumerated,
sizeof(data->value.enumerated)))
return -EFAULT;
break;
default:
break;
}
return 0;
}
/* read / write */
struct snd_ctl_elem_value32 {
struct snd_ctl_elem_id id;
unsigned int indirect; /* bit-field causes misalignment */
union {
s32 integer[128];
unsigned char data[512];
#ifndef CONFIG_X86_64
s64 integer64[64];
#endif
} value;
unsigned char reserved[128];
};
#ifdef CONFIG_X86_X32_ABI
/* x32 has a different alignment for 64bit values from ia32 */
struct snd_ctl_elem_value_x32 {
struct snd_ctl_elem_id id;
unsigned int indirect; /* bit-field causes misalignment */
union {
s32 integer[128];
unsigned char data[512];
s64 integer64[64];
} value;
unsigned char reserved[128];
};
#endif /* CONFIG_X86_X32_ABI */
/* get the value type and count of the control */
static int get_ctl_type(struct snd_card *card, struct snd_ctl_elem_id *id,
int *countp)
{
struct snd_kcontrol *kctl;
struct snd_ctl_elem_info *info __free(kfree) = NULL;
int err;
guard(rwsem_read)(&card->controls_rwsem);
kctl = snd_ctl_find_id_locked(card, id);
if (!kctl)
return -ENOENT;
info = kzalloc(sizeof(*info), GFP_KERNEL);
if (info == NULL)
return -ENOMEM;
info->id = *id;
err = snd_power_ref_and_wait(card);
if (!err)
err = kctl->info(kctl, info);
snd_power_unref(card);
if (err >= 0) {
err = info->type;
*countp = info->count;
}
return err;
}
static int get_elem_size(snd_ctl_elem_type_t type, int count)
{
switch (type) {
case SNDRV_CTL_ELEM_TYPE_INTEGER64:
return sizeof(s64) * count;
case SNDRV_CTL_ELEM_TYPE_ENUMERATED:
return sizeof(int) * count;
case SNDRV_CTL_ELEM_TYPE_BYTES:
return 512;
case SNDRV_CTL_ELEM_TYPE_IEC958:
return sizeof(struct snd_aes_iec958);
default:
return -1;
}
}
static int copy_ctl_value_from_user(struct snd_card *card,
struct snd_ctl_elem_value *data,
void __user *userdata,
void __user *valuep,
int *typep, int *countp)
{
struct snd_ctl_elem_value32 __user *data32 = userdata;
int i, type, size;
int count;
unsigned int indirect;
if (copy_from_user(&data->id, &data32->id, sizeof(data->id)))
return -EFAULT;
if (get_user(indirect, &data32->indirect))
return -EFAULT;
if (indirect)
return -EINVAL;
type = get_ctl_type(card, &data->id, &count);
if (type < 0)
return type;
if (type == (__force int)SNDRV_CTL_ELEM_TYPE_BOOLEAN ||
type == (__force int)SNDRV_CTL_ELEM_TYPE_INTEGER) {
for (i = 0; i < count; i++) {
s32 __user *intp = valuep;
int val;
if (get_user(val, &intp[i]))
return -EFAULT;
data->value.integer.value[i] = val;
}
} else {
size = get_elem_size((__force snd_ctl_elem_type_t)type, count);
if (size < 0) {
dev_err(card->dev, "snd_ioctl32_ctl_elem_value: unknown type %d\n", type);
return -EINVAL;
}
if (copy_from_user(data->value.bytes.data, valuep, size))
return -EFAULT;
}
*typep = type;
*countp = count;
return 0;
}
/* restore the value to 32bit */
static int copy_ctl_value_to_user(void __user *userdata,
void __user *valuep,
struct snd_ctl_elem_value *data,
int type, int count)
{
struct snd_ctl_elem_value32 __user *data32 = userdata;
int i, size;
if (type == (__force int)SNDRV_CTL_ELEM_TYPE_BOOLEAN ||
type == (__force int)SNDRV_CTL_ELEM_TYPE_INTEGER) {
for (i = 0; i < count; i++) {
s32 __user *intp = valuep;
int val;
val = data->value.integer.value[i];
if (put_user(val, &intp[i]))
return -EFAULT;
}
} else {
size = get_elem_size((__force snd_ctl_elem_type_t)type, count);
if (copy_to_user(valuep, data->value.bytes.data, size))
return -EFAULT;
}
if (copy_to_user(&data32->id, &data->id, sizeof(data32->id)))
return -EFAULT;
return 0;
}
static int ctl_elem_read_user(struct snd_card *card,
void __user *userdata, void __user *valuep)
{
struct snd_ctl_elem_value *data __free(kfree) = NULL;
int err, type, count;
data = kzalloc(sizeof(*data), GFP_KERNEL);
if (data == NULL)
return -ENOMEM;
err = copy_ctl_value_from_user(card, data, userdata, valuep,
&type, &count);
if (err < 0)
return err;
err = snd_ctl_elem_read(card, data);
if (err < 0)
return err;
return copy_ctl_value_to_user(userdata, valuep, data, type, count);
}
static int ctl_elem_write_user(struct snd_ctl_file *file,
void __user *userdata, void __user *valuep)
{
struct snd_ctl_elem_value *data __free(kfree) = NULL;
struct snd_card *card = file->card;
int err, type, count;
data = kzalloc(sizeof(*data), GFP_KERNEL);
if (data == NULL)
return -ENOMEM;
err = copy_ctl_value_from_user(card, data, userdata, valuep,
&type, &count);
if (err < 0)
return err;
err = snd_ctl_elem_write(card, file, data);
if (err < 0)
return err;
return copy_ctl_value_to_user(userdata, valuep, data, type, count);
}
static int snd_ctl_elem_read_user_compat(struct snd_card *card,
struct snd_ctl_elem_value32 __user *data32)
{
return ctl_elem_read_user(card, data32, &data32->value);
}
static int snd_ctl_elem_write_user_compat(struct snd_ctl_file *file,
struct snd_ctl_elem_value32 __user *data32)
{
return ctl_elem_write_user(file, data32, &data32->value);
}
#ifdef CONFIG_X86_X32_ABI
static int snd_ctl_elem_read_user_x32(struct snd_card *card,
struct snd_ctl_elem_value_x32 __user *data32)
{
return ctl_elem_read_user(card, data32, &data32->value);
}
static int snd_ctl_elem_write_user_x32(struct snd_ctl_file *file,
struct snd_ctl_elem_value_x32 __user *data32)
{
return ctl_elem_write_user(file, data32, &data32->value);
}
#endif /* CONFIG_X86_X32_ABI */
/* add or replace a user control */
static int snd_ctl_elem_add_compat(struct snd_ctl_file *file,
struct snd_ctl_elem_info32 __user *data32,
int replace)
{
struct snd_ctl_elem_info *data __free(kfree) = NULL;
data = kzalloc(sizeof(*data), GFP_KERNEL);
if (! data)
return -ENOMEM;
/* id, type, access, count */ \
if (copy_from_user(&data->id, &data32->id, sizeof(data->id)) ||
copy_from_user(&data->type, &data32->type, 3 * sizeof(u32)))
return -EFAULT;
if (get_user(data->owner, &data32->owner))
return -EFAULT;
switch (data->type) {
case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
case SNDRV_CTL_ELEM_TYPE_INTEGER:
if (get_user(data->value.integer.min, &data32->value.integer.min) ||
get_user(data->value.integer.max, &data32->value.integer.max) ||
get_user(data->value.integer.step, &data32->value.integer.step))
return -EFAULT;
break;
case SNDRV_CTL_ELEM_TYPE_INTEGER64:
if (copy_from_user(&data->value.integer64,
&data32->value.integer64,
sizeof(data->value.integer64)))
return -EFAULT;
break;
case SNDRV_CTL_ELEM_TYPE_ENUMERATED:
if (copy_from_user(&data->value.enumerated,
&data32->value.enumerated,
sizeof(data->value.enumerated)))
return -EFAULT;
data->value.enumerated.names_ptr =
(uintptr_t)compat_ptr(data->value.enumerated.names_ptr);
break;
default:
break;
}
return snd_ctl_elem_add(file, data, replace);
}
enum {
SNDRV_CTL_IOCTL_ELEM_LIST32 = _IOWR('U', 0x10, struct snd_ctl_elem_list32),
SNDRV_CTL_IOCTL_ELEM_INFO32 = _IOWR('U', 0x11, struct snd_ctl_elem_info32),
SNDRV_CTL_IOCTL_ELEM_READ32 = _IOWR('U', 0x12, struct snd_ctl_elem_value32),
SNDRV_CTL_IOCTL_ELEM_WRITE32 = _IOWR('U', 0x13, struct snd_ctl_elem_value32),
SNDRV_CTL_IOCTL_ELEM_ADD32 = _IOWR('U', 0x17, struct snd_ctl_elem_info32),
SNDRV_CTL_IOCTL_ELEM_REPLACE32 = _IOWR('U', 0x18, struct snd_ctl_elem_info32),
#ifdef CONFIG_X86_X32_ABI
SNDRV_CTL_IOCTL_ELEM_READ_X32 = _IOWR('U', 0x12, struct snd_ctl_elem_value_x32),
SNDRV_CTL_IOCTL_ELEM_WRITE_X32 = _IOWR('U', 0x13, struct snd_ctl_elem_value_x32),
#endif /* CONFIG_X86_X32_ABI */
};
static inline long snd_ctl_ioctl_compat(struct file *file, unsigned int cmd, unsigned long arg)
{
struct snd_ctl_file *ctl;
struct snd_kctl_ioctl *p;
void __user *argp = compat_ptr(arg);
int err;
ctl = file->private_data;
if (snd_BUG_ON(!ctl || !ctl->card))
return -ENXIO;
switch (cmd) {
case SNDRV_CTL_IOCTL_PVERSION:
case SNDRV_CTL_IOCTL_CARD_INFO:
case SNDRV_CTL_IOCTL_SUBSCRIBE_EVENTS:
case SNDRV_CTL_IOCTL_POWER:
case SNDRV_CTL_IOCTL_POWER_STATE:
case SNDRV_CTL_IOCTL_ELEM_LOCK:
case SNDRV_CTL_IOCTL_ELEM_UNLOCK:
case SNDRV_CTL_IOCTL_ELEM_REMOVE:
case SNDRV_CTL_IOCTL_TLV_READ:
case SNDRV_CTL_IOCTL_TLV_WRITE:
case SNDRV_CTL_IOCTL_TLV_COMMAND:
return snd_ctl_ioctl(file, cmd, (unsigned long)argp);
case SNDRV_CTL_IOCTL_ELEM_LIST32:
return snd_ctl_elem_list_compat(ctl->card, argp);
case SNDRV_CTL_IOCTL_ELEM_INFO32:
return snd_ctl_elem_info_compat(ctl, argp);
case SNDRV_CTL_IOCTL_ELEM_READ32:
return snd_ctl_elem_read_user_compat(ctl->card, argp);
case SNDRV_CTL_IOCTL_ELEM_WRITE32:
return snd_ctl_elem_write_user_compat(ctl, argp);
case SNDRV_CTL_IOCTL_ELEM_ADD32:
return snd_ctl_elem_add_compat(ctl, argp, 0);
case SNDRV_CTL_IOCTL_ELEM_REPLACE32:
return snd_ctl_elem_add_compat(ctl, argp, 1);
#ifdef CONFIG_X86_X32_ABI
case SNDRV_CTL_IOCTL_ELEM_READ_X32:
return snd_ctl_elem_read_user_x32(ctl->card, argp);
case SNDRV_CTL_IOCTL_ELEM_WRITE_X32:
return snd_ctl_elem_write_user_x32(ctl, argp);
#endif /* CONFIG_X86_X32_ABI */
}
guard(rwsem_read)(&snd_ioctl_rwsem);
list_for_each_entry(p, &snd_control_compat_ioctls, list) {
if (p->fioctl) {
err = p->fioctl(ctl->card, ctl, cmd, arg);
if (err != -ENOIOCTLCMD)
return err;
}
}
return -ENOIOCTLCMD;
}
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