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| author | Takashi Iwai <tiwai@suse.de> | 2019-08-25 09:21:44 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-09-06 10:20:52 +0200 |
| commit | ed2d2a172c5f4ab32bdf92e4e5a9f033a75f7b6b (patch) | |
| tree | f9a71ae1a59f1ab3427eae6c949806f40ffcdbe6 | |
| parent | 0cb49ca2dc8bf9ee50d1b2ceb42a86bb6c8dc15d (diff) | |
| download | linux-stable-ed2d2a172c5f4ab32bdf92e4e5a9f033a75f7b6b.tar.gz linux-stable-ed2d2a172c5f4ab32bdf92e4e5a9f033a75f7b6b.tar.bz2 linux-stable-ed2d2a172c5f4ab32bdf92e4e5a9f033a75f7b6b.zip | |
ALSA: seq: Fix potential concurrent access to the deleted pool
commit 75545304eba6a3d282f923b96a466dc25a81e359 upstream.
The input pool of a client might be deleted via the resize ioctl, the
the access to it should be covered by the proper locks. Currently the
only missing place is the call in snd_seq_ioctl_get_client_pool(), and
this patch papers over it.
Reported-by: syzbot+4a75454b9ca2777f35c7@syzkaller.appspotmail.com
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | sound/core/seq/seq_clientmgr.c | 3 | ||||
| -rw-r--r-- | sound/core/seq/seq_fifo.c | 17 | ||||
| -rw-r--r-- | sound/core/seq/seq_fifo.h | 2 |
3 files changed, 20 insertions, 2 deletions
diff --git a/sound/core/seq/seq_clientmgr.c b/sound/core/seq/seq_clientmgr.c index cc5b4c25d6f1..92b0d4523a07 100644 --- a/sound/core/seq/seq_clientmgr.c +++ b/sound/core/seq/seq_clientmgr.c @@ -1821,8 +1821,7 @@ static int snd_seq_ioctl_get_client_pool(struct snd_seq_client *client, if (cptr->type == USER_CLIENT) { info->input_pool = cptr->data.user.fifo_pool_size; info->input_free = info->input_pool; - if (cptr->data.user.fifo) - info->input_free = snd_seq_unused_cells(cptr->data.user.fifo->pool); + info->input_free = snd_seq_fifo_unused_cells(cptr->data.user.fifo); } else { info->input_pool = 0; info->input_free = 0; diff --git a/sound/core/seq/seq_fifo.c b/sound/core/seq/seq_fifo.c index 72c0302a55d2..6a24732704fc 100644 --- a/sound/core/seq/seq_fifo.c +++ b/sound/core/seq/seq_fifo.c @@ -280,3 +280,20 @@ int snd_seq_fifo_resize(struct snd_seq_fifo *f, int poolsize) return 0; } + +/* get the number of unused cells safely */ +int snd_seq_fifo_unused_cells(struct snd_seq_fifo *f) +{ + unsigned long flags; + int cells; + + if (!f) + return 0; + + snd_use_lock_use(&f->use_lock); + spin_lock_irqsave(&f->lock, flags); + cells = snd_seq_unused_cells(f->pool); + spin_unlock_irqrestore(&f->lock, flags); + snd_use_lock_free(&f->use_lock); + return cells; +} diff --git a/sound/core/seq/seq_fifo.h b/sound/core/seq/seq_fifo.h index 062c446e7867..5d38a0d7f0cd 100644 --- a/sound/core/seq/seq_fifo.h +++ b/sound/core/seq/seq_fifo.h @@ -68,5 +68,7 @@ int snd_seq_fifo_poll_wait(struct snd_seq_fifo *f, struct file *file, poll_table /* resize pool in fifo */ int snd_seq_fifo_resize(struct snd_seq_fifo *f, int poolsize); +/* get the number of unused cells safely */ +int snd_seq_fifo_unused_cells(struct snd_seq_fifo *f); #endif |