diff options
| author | Lars-Peter Clausen <lars@metafoo.de> | 2014-06-18 13:32:31 +0200 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2014-06-18 15:12:33 +0200 |
| commit | 07f4d9d74a04aa7c72c5dae0ef97565f28f17b92 (patch) | |
| tree | 65d9ee5f96dacb86a33d3a8cd786e876563d93ac /sound/core/init.c | |
| parent | 7171511eaec5bf23fb06078f59784a3a0626b38f (diff) | |
ALSA: control: Protect user controls against concurrent access
The user-control put and get handlers as well as the tlv do not protect against
concurrent access from multiple threads. Since the state of the control is not
updated atomically it is possible that either two write operations or a write
and a read operation race against each other. Both can lead to arbitrary memory
disclosure. This patch introduces a new lock that protects user-controls from
concurrent access. Since applications typically access controls sequentially
than in parallel a single lock per card should be fine.
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>
Diffstat (limited to 'sound/core/init.c')
| -rw-r--r-- | sound/core/init.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/sound/core/init.c b/sound/core/init.c index 5ee83845c5de..7bdfd19e24a8 100644 --- a/sound/core/init.c +++ b/sound/core/init.c @@ -232,6 +232,7 @@ int snd_card_new(struct device *parent, int idx, const char *xid, INIT_LIST_HEAD(&card->devices); init_rwsem(&card->controls_rwsem); rwlock_init(&card->ctl_files_rwlock); + mutex_init(&card->user_ctl_lock); INIT_LIST_HEAD(&card->controls); INIT_LIST_HEAD(&card->ctl_files); spin_lock_init(&card->files_lock); |