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| author | Alan Young <consult.awy@gmail.com> | 2021-12-02 15:06:07 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-12-14 10:18:05 +0100 |
| commit | fd753901ca921877cf585dc315dd5b36f672a404 (patch) | |
| tree | caa311e8803b1e509375cf830fc5a7ce5ea9658a /sound | |
| parent | 505039dd0fe6493565e27b55700e46f43f20580d (diff) | |
| download | linux-stable-fd753901ca921877cf585dc315dd5b36f672a404.tar.gz linux-stable-fd753901ca921877cf585dc315dd5b36f672a404.tar.bz2 linux-stable-fd753901ca921877cf585dc315dd5b36f672a404.zip | |
ALSA: ctl: Fix copy of updated id with element read/write
commit b6409dd6bdc03aa178bbff0d80db2a30d29b63ac upstream.
When control_compat.c:copy_ctl_value_to_user() is used, by
ctl_elem_read_user() & ctl_elem_write_user(), it must also copy back the
snd_ctl_elem_id value that may have been updated (filled in) by the call
to snd_ctl_elem_read/snd_ctl_elem_write().
This matches the functionality provided by snd_ctl_elem_read_user() and
snd_ctl_elem_write_user(), via snd_ctl_build_ioff().
Without this, and without making additional calls to snd_ctl_info()
which are unnecessary when using the non-compat calls, a userspace
application will not know the numid value for the element and
consequently will not be able to use the poll/read interface on the
control file to determine which elements have updates.
Signed-off-by: Alan Young <consult.awy@gmail.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20211202150607.543389-1-consult.awy@gmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'sound')
| -rw-r--r-- | sound/core/control_compat.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/sound/core/control_compat.c b/sound/core/control_compat.c index 507fd5210c1c..3fc216644e0e 100644 --- a/sound/core/control_compat.c +++ b/sound/core/control_compat.c @@ -279,6 +279,7 @@ static int copy_ctl_value_to_user(void __user *userdata, struct snd_ctl_elem_value *data, int type, int count) { + struct snd_ctl_elem_value32 __user *data32 = userdata; int i, size; if (type == SNDRV_CTL_ELEM_TYPE_BOOLEAN || @@ -295,6 +296,8 @@ static int copy_ctl_value_to_user(void __user *userdata, 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; } |