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| author | Lars-Peter Clausen <lars@metafoo.de> | 2014-06-18 13:32:33 +0200 |
|---|---|---|
| committer | Willy Tarreau <w@1wt.eu> | 2014-12-13 15:16:13 +0100 |
| commit | c99bd4fceec6135a31f95de4716a42e2064909bf (patch) | |
| tree | 34f4b6f8c247710f4d8481b107a62ba034eba45e /sound | |
| parent | eb406993c7b80c68b053c5d3d6431f4b8d0560eb (diff) | |
| download | lwn-c99bd4fceec6135a31f95de4716a42e2064909bf.tar.gz lwn-c99bd4fceec6135a31f95de4716a42e2064909bf.zip | |
ALSA: control: Don't access controls outside of protected regions
(commit fd9f26e4eca5d08a27d12c0933fceef76ed9663d upstream)
A control that is visible on the card->controls list can be freed at any time.
This means we must not access any of its memory while not holding the
controls_rw_lock. Otherwise we risk a use after free access.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Jaroslav Kysela <perex@perex.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
[wt: fixes CVE-2014-4653]
Signed-off-by: Willy Tarreau <w@1wt.eu>
Diffstat (limited to 'sound')
| -rw-r--r-- | sound/core/control.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/sound/core/control.c b/sound/core/control.c index 8bf3a6d1ebe2..e91d79a9ec4b 100644 --- a/sound/core/control.c +++ b/sound/core/control.c @@ -325,6 +325,7 @@ int snd_ctl_add(struct snd_card *card, struct snd_kcontrol *kcontrol) { struct snd_ctl_elem_id id; unsigned int idx; + unsigned int count; int err = -EINVAL; if (! kcontrol) @@ -356,8 +357,9 @@ int snd_ctl_add(struct snd_card *card, struct snd_kcontrol *kcontrol) card->controls_count += kcontrol->count; kcontrol->id.numid = card->last_numid + 1; card->last_numid += kcontrol->count; + count = kcontrol->count; up_write(&card->controls_rwsem); - for (idx = 0; idx < kcontrol->count; idx++, id.index++, id.numid++) + for (idx = 0; idx < count; idx++, id.index++, id.numid++) snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_ADD, &id); return 0; @@ -784,9 +786,9 @@ static int snd_ctl_elem_write(struct snd_card *card, struct snd_ctl_file *file, result = kctl->put(kctl, control); } if (result > 0) { + struct snd_ctl_elem_id id = control->id; up_read(&card->controls_rwsem); - snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, - &control->id); + snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, &id); return 0; } } |