2.6.32-longterm review patch. If anyone has any objections, please let me know.
------------------
From: Lars-Peter Clausen <l...@metafoo.de>
(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 <l...@metafoo.de>
Acked-by: Jaroslav Kysela <pe...@perex.cz>
Cc: <sta...@vger.kernel.org>
Signed-off-by: Takashi Iwai <ti...@suse.de>
[wt: fixes CVE-2014-4653]
Signed-off-by: Willy Tarreau <w...@1wt.eu>
---
sound/core/control.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/sound/core/control.c b/sound/core/control.c
index 8bf3a6d..e91d79a 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;
}
}
--
1.7.12.2.21.g234cd45.dirty
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