[PATCH] ALSA: compat_ioctl: avoid compat_alloc_user_space
Arnd Bergmann
arnd at arndb.de
Fri Sep 18 11:56:19 CEST 2020
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 at arndb.de>
---
sound/core/control.c | 38 ++++++++++++++++++++++++-------------
sound/core/control_compat.c | 14 ++++++--------
sound/core/hwdep.c | 27 ++++++++++++++++----------
sound/core/hwdep_compat.c | 23 +++++++---------------
4 files changed, 55 insertions(+), 47 deletions(-)
diff --git a/sound/core/control.c b/sound/core/control.c
index aa0c0cf182af..e014598142df 100644
--- a/sound/core/control.c
+++ b/sound/core/control.c
@@ -717,22 +717,19 @@ static int snd_ctl_card_info(struct snd_card *card, struct snd_ctl_file * ctl,
}
static int snd_ctl_elem_list(struct snd_card *card,
- struct snd_ctl_elem_list __user *_list)
+ struct snd_ctl_elem_list *list)
{
- struct snd_ctl_elem_list list;
struct snd_kcontrol *kctl;
struct snd_ctl_elem_id id;
unsigned int offset, space, jidx;
int err = 0;
- if (copy_from_user(&list, _list, sizeof(list)))
- return -EFAULT;
- offset = list.offset;
- space = list.space;
+ offset = list->offset;
+ space = list->space;
down_read(&card->controls_rwsem);
- list.count = card->controls_count;
- list.used = 0;
+ list->count = card->controls_count;
+ list->used = 0;
if (space > 0) {
list_for_each_entry(kctl, &card->controls, list) {
if (offset >= kctl->count) {
@@ -741,12 +738,12 @@ static int snd_ctl_elem_list(struct snd_card *card,
}
for (jidx = offset; jidx < kctl->count; jidx++) {
snd_ctl_build_ioff(&id, kctl, jidx);
- if (copy_to_user(list.pids + list.used, &id,
+ if (copy_to_user(list->pids + list->used, &id,
sizeof(id))) {
err = -EFAULT;
goto out;
}
- list.used++;
+ list->used++;
if (!--space)
goto out;
}
@@ -755,11 +752,26 @@ static int snd_ctl_elem_list(struct snd_card *card,
}
out:
up_read(&card->controls_rwsem);
- if (!err && copy_to_user(_list, &list, sizeof(list)))
- err = -EFAULT;
return err;
}
+static int snd_ctl_elem_list_user(struct snd_card *card,
+ struct snd_ctl_elem_list __user *_list)
+{
+ struct snd_ctl_elem_list list;
+ int err;
+
+ if (copy_from_user(&list, _list, sizeof(list)))
+ return -EFAULT;
+ err = snd_ctl_elem_list(card, &list);
+ if (err)
+ return err;
+ if (copy_to_user(_list, &list, sizeof(list)))
+ return -EFAULT;
+
+ return 0;
+}
+
/* Check whether the given kctl info is valid */
static int snd_ctl_check_elem_info(struct snd_card *card,
const struct snd_ctl_elem_info *info)
@@ -1703,7 +1715,7 @@ static long snd_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg
case SNDRV_CTL_IOCTL_CARD_INFO:
return snd_ctl_card_info(card, ctl, cmd, argp);
case SNDRV_CTL_IOCTL_ELEM_LIST:
- return snd_ctl_elem_list(card, argp);
+ return snd_ctl_elem_list_user(card, argp);
case SNDRV_CTL_IOCTL_ELEM_INFO:
return snd_ctl_elem_info_user(ctl, argp);
case SNDRV_CTL_IOCTL_ELEM_READ:
diff --git a/sound/core/control_compat.c b/sound/core/control_compat.c
index 02df1d7db9a1..1d708aab9c98 100644
--- a/sound/core/control_compat.c
+++ b/sound/core/control_compat.c
@@ -22,24 +22,22 @@ struct snd_ctl_elem_list32 {
static int snd_ctl_elem_list_compat(struct snd_card *card,
struct snd_ctl_elem_list32 __user *data32)
{
- struct snd_ctl_elem_list __user *data;
+ struct snd_ctl_elem_list data = {};
compat_caddr_t ptr;
int err;
- data = compat_alloc_user_space(sizeof(*data));
-
/* offset, space, used, count */
- if (copy_in_user(data, data32, 4 * sizeof(u32)))
+ if (copy_from_user(&data, data32, 4 * sizeof(u32)))
return -EFAULT;
/* pids */
- if (get_user(ptr, &data32->pids) ||
- put_user(compat_ptr(ptr), &data->pids))
+ if (get_user(ptr, &data32->pids))
return -EFAULT;
- err = snd_ctl_elem_list(card, data);
+ data.pids = compat_ptr(ptr);
+ err = snd_ctl_elem_list(card, &data);
if (err < 0)
return err;
/* copy the result */
- if (copy_in_user(data32, data, 4 * sizeof(u32)))
+ if (copy_to_user(data32, &data, 4 * sizeof(u32)))
return -EFAULT;
return 0;
}
diff --git a/sound/core/hwdep.c b/sound/core/hwdep.c
index 21edb8ac95eb..0c029892880a 100644
--- a/sound/core/hwdep.c
+++ b/sound/core/hwdep.c
@@ -203,28 +203,35 @@ static int snd_hwdep_dsp_status(struct snd_hwdep *hw,
}
static int snd_hwdep_dsp_load(struct snd_hwdep *hw,
- struct snd_hwdep_dsp_image __user *_info)
+ struct snd_hwdep_dsp_image *info)
{
- struct snd_hwdep_dsp_image info;
int err;
if (! hw->ops.dsp_load)
return -ENXIO;
- memset(&info, 0, sizeof(info));
- if (copy_from_user(&info, _info, sizeof(info)))
- return -EFAULT;
- if (info.index >= 32)
+ if (info->index >= 32)
return -EINVAL;
/* check whether the dsp was already loaded */
- if (hw->dsp_loaded & (1u << info.index))
+ if (hw->dsp_loaded & (1u << info->index))
return -EBUSY;
- err = hw->ops.dsp_load(hw, &info);
+ err = hw->ops.dsp_load(hw, info);
if (err < 0)
return err;
- hw->dsp_loaded |= (1u << info.index);
+ hw->dsp_loaded |= (1u << info->index);
return 0;
}
+static int snd_hwdep_dsp_load_user(struct snd_hwdep *hw,
+ struct snd_hwdep_dsp_image __user *_info)
+{
+ struct snd_hwdep_dsp_image info = {};
+
+ if (copy_from_user(&info, _info, sizeof(info)))
+ return -EFAULT;
+ return snd_hwdep_dsp_load(hw, &info);
+}
+
+
static long snd_hwdep_ioctl(struct file * file, unsigned int cmd,
unsigned long arg)
{
@@ -238,7 +245,7 @@ static long snd_hwdep_ioctl(struct file * file, unsigned int cmd,
case SNDRV_HWDEP_IOCTL_DSP_STATUS:
return snd_hwdep_dsp_status(hw, argp);
case SNDRV_HWDEP_IOCTL_DSP_LOAD:
- return snd_hwdep_dsp_load(hw, argp);
+ return snd_hwdep_dsp_load_user(hw, argp);
}
if (hw->ops.ioctl)
return hw->ops.ioctl(hw, file, cmd, arg);
diff --git a/sound/core/hwdep_compat.c b/sound/core/hwdep_compat.c
index bc81db9cb3d4..a0b76706c083 100644
--- a/sound/core/hwdep_compat.c
+++ b/sound/core/hwdep_compat.c
@@ -19,26 +19,17 @@ struct snd_hwdep_dsp_image32 {
static int snd_hwdep_dsp_load_compat(struct snd_hwdep *hw,
struct snd_hwdep_dsp_image32 __user *src)
{
- struct snd_hwdep_dsp_image __user *dst;
+ struct snd_hwdep_dsp_image info = {};
compat_caddr_t ptr;
- u32 val;
- dst = compat_alloc_user_space(sizeof(*dst));
-
- /* index and name */
- if (copy_in_user(dst, src, 4 + 64))
- return -EFAULT;
- if (get_user(ptr, &src->image) ||
- put_user(compat_ptr(ptr), &dst->image))
- return -EFAULT;
- if (get_user(val, &src->length) ||
- put_user(val, &dst->length))
- return -EFAULT;
- if (get_user(val, &src->driver_data) ||
- put_user(val, &dst->driver_data))
+ 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, dst);
+ return snd_hwdep_dsp_load(hw, &info);
}
enum {
--
2.27.0
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