diff options
| author | Lars-Peter Clausen <lars@metafoo.de> | 2014-06-18 13:32:33 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-06-26 15:10:29 -0400 |
| commit | 291cd312b3c2826892299a74249fc9a88fb3305f (patch) | |
| tree | adf90a1652d356bf6d1e56d89073cfb6eb7a5fc8 | |
| parent | 8e6cbc9765746148dbebd35b2531f31b3ee8dbf8 (diff) | |
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>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | sound/core/control.c | 15 |
1 files changed, 10 insertions, 5 deletions
diff --git a/sound/core/control.c b/sound/core/control.c index 2fd3662f06c6..4c8d9e34872d 100644 --- a/sound/core/control.c +++ b/sound/core/control.c @@ -329,6 +329,7 @@ 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) @@ -357,8 +358,9 @@ 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; @@ -387,6 +389,7 @@ int snd_ctl_replace(struct snd_card *card, struct snd_kcontrol *kcontrol, bool add_on_replace) { struct snd_ctl_elem_id id; + unsigned int count; unsigned int idx; struct snd_kcontrol *old; int ret; @@ -422,8 +425,9 @@ add: 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; @@ -894,9 +898,9 @@ 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; } } @@ -1330,8 +1334,9 @@ static int snd_ctl_tlv_ioctl(struct snd_ctl_file *file, } err = kctl->tlv.c(kctl, op_flag, tlv.length, _tlv->tlv); if (err > 0) { + struct snd_ctl_elem_id id = kctl->id; up_read(&card->controls_rwsem); - snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_TLV, &kctl->id); + snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_TLV, &id); return 0; } } else { |