From 18dd0aa5afea7dc33953aa87de696e39074bbf78 Mon Sep 17 00:00:00 2001 From: Clemens Ladisch Date: Mon, 17 Aug 2009 12:28:09 +0200 Subject: [PATCH] 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: Clemens Ladisch Signed-off-by: Takashi Iwai --- sound/core/control.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/sound/core/control.c b/sound/core/control.c index bc64b72..a8b7fab 100644 --- a/sound/core/control.c +++ b/sound/core/control.c @@ -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; -- 1.8.2.3