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linux-next/sound/core/seq/seq_fifo.h
Takashi Iwai 75545304eb ALSA: seq: Fix potential concurrent access to the deleted pool
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>
2019-08-25 09:31:10 +02:00

60 lines
1.7 KiB
C

/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* ALSA sequencer FIFO
* Copyright (c) 1998 by Frank van de Pol <fvdpol@coil.demon.nl>
*/
#ifndef __SND_SEQ_FIFO_H
#define __SND_SEQ_FIFO_H
#include "seq_memory.h"
#include "seq_lock.h"
/* === FIFO === */
struct snd_seq_fifo {
struct snd_seq_pool *pool; /* FIFO pool */
struct snd_seq_event_cell *head; /* pointer to head of fifo */
struct snd_seq_event_cell *tail; /* pointer to tail of fifo */
int cells;
spinlock_t lock;
snd_use_lock_t use_lock;
wait_queue_head_t input_sleep;
atomic_t overflow;
};
/* create new fifo (constructor) */
struct snd_seq_fifo *snd_seq_fifo_new(int poolsize);
/* delete fifo (destructor) */
void snd_seq_fifo_delete(struct snd_seq_fifo **f);
/* enqueue event to fifo */
int snd_seq_fifo_event_in(struct snd_seq_fifo *f, struct snd_seq_event *event);
/* lock fifo from release */
#define snd_seq_fifo_lock(fifo) snd_use_lock_use(&(fifo)->use_lock)
#define snd_seq_fifo_unlock(fifo) snd_use_lock_free(&(fifo)->use_lock)
/* get a cell from fifo - fifo should be locked */
int snd_seq_fifo_cell_out(struct snd_seq_fifo *f, struct snd_seq_event_cell **cellp, int nonblock);
/* free dequeued cell - fifo should be locked */
void snd_seq_fifo_cell_putback(struct snd_seq_fifo *f, struct snd_seq_event_cell *cell);
/* clean up queue */
void snd_seq_fifo_clear(struct snd_seq_fifo *f);
/* polling */
int snd_seq_fifo_poll_wait(struct snd_seq_fifo *f, struct file *file, poll_table *wait);
/* 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