Commit 18dd0aa5 authored by Clemens Ladisch's avatar Clemens Ladisch Committed by Takashi Iwai
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sound: snd_ctl_remove_user_ctl: prevent removal of kernel controls 



Ensure that userspace can remove only user controls.  Controls created
by kernel drivers must not be removed because they might be referenced
in calls to snd_ctl_notify().

Signed-off-by: default avatarClemens Ladisch <clemens@ladisch.de>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent f217ac59

sound/core/control.c

+4 −0
Original line number Diff line number Diff line
@@ -436,6 +436,10 @@ static int snd_ctl_remove_user_ctl(struct snd_ctl_file * file, 
		ret = -ENOENT;

		goto error;

	}

	if (!(kctl->vd[0].access & SNDRV_CTL_ELEM_ACCESS_USER)) {

		ret = -EINVAL;

		goto error;

	}

	for (idx = 0; idx < kctl->count; idx++)

		if (kctl->vd[idx].owner != NULL && kctl->vd[idx].owner != file) {

			ret = -EBUSY;