diff options
| author | Arnd Bergmann <arnd@arndb.de> | 2020-09-18 11:56:19 +0200 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2020-09-21 10:37:07 +0200 |
| commit | 18d122c0287b29e70bc312a994c7ee79738cec77 (patch) | |
| tree | 5310fec9f6a909f465b97350cf4fda5105149361 /sound/core/control.c | |
| parent | 2b987515e1d18836d9df96a5876290c8c8208348 (diff) | |
| download | linux-18d122c0287b29e70bc312a994c7ee79738cec77.tar.bz2 | |
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>
Diffstat (limited to 'sound/core/control.c')
| -rw-r--r-- | sound/core/control.c | 38 |
1 files changed, 25 insertions, 13 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: |