a507658fdb
commit c1f6e3c818dd734c30f6a7eeebf232ba2cf3181d upstream. The rawmidi core allows user to resize the runtime buffer via ioctl, and this may lead to UAF when performed during concurrent reads or writes: the read/write functions unlock the runtime lock temporarily during copying form/to user-space, and that's the race window. This patch fixes the hole by introducing a reference counter for the runtime buffer read/write access and returns -EBUSY error when the resize is performed concurrently against read/write. Note that the ref count field is a simple integer instead of refcount_t here, since the all contexts accessing the buffer is basically protected with a spinlock, hence we need no expensive atomic ops. Also, note that this busy check is needed only against read / write functions, and not in receive/transmit callbacks; the race can happen only at the spinlock hole mentioned in the above, while the whole function is protected for receive / transmit callbacks. Reported-by: butt3rflyh4ck <butterflyhuangxx@gmail.com> Cc: <stable@vger.kernel.org> Link: https://lore.kernel.org/r/CAFcO6XMWpUVK_yzzCpp8_XP7+=oUpQvuBeCbMffEDkpe8jWrfg@mail.gmail.com Link: https://lore.kernel.org/r/s5heerw3r5z.wl-tiwai@suse.de Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
194 lines
6.2 KiB
C
194 lines
6.2 KiB
C
#ifndef __SOUND_RAWMIDI_H
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#define __SOUND_RAWMIDI_H
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/*
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* Abstract layer for MIDI v1.0 stream
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* Copyright (c) by Jaroslav Kysela <perex@perex.cz>
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*
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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*/
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#include <sound/asound.h>
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#include <linux/interrupt.h>
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#include <linux/spinlock.h>
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#include <linux/wait.h>
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#include <linux/mutex.h>
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#include <linux/workqueue.h>
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#include <linux/device.h>
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#if IS_ENABLED(CONFIG_SND_SEQUENCER)
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#include <sound/seq_device.h>
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#endif
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/*
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* Raw MIDI interface
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*/
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#define SNDRV_RAWMIDI_DEVICES 8
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#define SNDRV_RAWMIDI_LFLG_OUTPUT (1<<0)
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#define SNDRV_RAWMIDI_LFLG_INPUT (1<<1)
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#define SNDRV_RAWMIDI_LFLG_OPEN (3<<0)
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#define SNDRV_RAWMIDI_LFLG_APPEND (1<<2)
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struct snd_rawmidi;
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struct snd_rawmidi_substream;
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struct snd_seq_port_info;
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struct pid;
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struct snd_rawmidi_ops {
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int (*open) (struct snd_rawmidi_substream * substream);
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int (*close) (struct snd_rawmidi_substream * substream);
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void (*trigger) (struct snd_rawmidi_substream * substream, int up);
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void (*drain) (struct snd_rawmidi_substream * substream);
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};
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struct snd_rawmidi_global_ops {
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int (*dev_register) (struct snd_rawmidi * rmidi);
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int (*dev_unregister) (struct snd_rawmidi * rmidi);
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void (*get_port_info)(struct snd_rawmidi *rmidi, int number,
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struct snd_seq_port_info *info);
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};
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struct snd_rawmidi_runtime {
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struct snd_rawmidi_substream *substream;
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unsigned int drain: 1, /* drain stage */
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oss: 1; /* OSS compatible mode */
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/* midi stream buffer */
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unsigned char *buffer; /* buffer for MIDI data */
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size_t buffer_size; /* size of buffer */
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size_t appl_ptr; /* application pointer */
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size_t hw_ptr; /* hardware pointer */
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size_t avail_min; /* min avail for wakeup */
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size_t avail; /* max used buffer for wakeup */
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size_t xruns; /* over/underruns counter */
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int buffer_ref; /* buffer reference count */
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/* misc */
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spinlock_t lock;
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wait_queue_head_t sleep;
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/* event handler (new bytes, input only) */
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void (*event)(struct snd_rawmidi_substream *substream);
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/* defers calls to event [input] or ops->trigger [output] */
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struct work_struct event_work;
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/* private data */
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void *private_data;
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void (*private_free)(struct snd_rawmidi_substream *substream);
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};
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struct snd_rawmidi_substream {
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struct list_head list; /* list of all substream for given stream */
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int stream; /* direction */
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int number; /* substream number */
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bool opened; /* open flag */
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bool append; /* append flag (merge more streams) */
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bool active_sensing; /* send active sensing when close */
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int use_count; /* use counter (for output) */
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size_t bytes;
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struct snd_rawmidi *rmidi;
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struct snd_rawmidi_str *pstr;
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char name[32];
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struct snd_rawmidi_runtime *runtime;
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struct pid *pid;
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/* hardware layer */
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const struct snd_rawmidi_ops *ops;
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};
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struct snd_rawmidi_file {
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struct snd_rawmidi *rmidi;
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struct snd_rawmidi_substream *input;
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struct snd_rawmidi_substream *output;
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};
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struct snd_rawmidi_str {
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unsigned int substream_count;
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unsigned int substream_opened;
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struct list_head substreams;
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};
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struct snd_rawmidi {
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struct snd_card *card;
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struct list_head list;
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unsigned int device; /* device number */
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unsigned int info_flags; /* SNDRV_RAWMIDI_INFO_XXXX */
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char id[64];
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char name[80];
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#ifdef CONFIG_SND_OSSEMUL
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int ossreg;
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#endif
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const struct snd_rawmidi_global_ops *ops;
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struct snd_rawmidi_str streams[2];
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void *private_data;
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void (*private_free) (struct snd_rawmidi *rmidi);
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struct mutex open_mutex;
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wait_queue_head_t open_wait;
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struct device dev;
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struct snd_info_entry *proc_entry;
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#if IS_ENABLED(CONFIG_SND_SEQUENCER)
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struct snd_seq_device *seq_dev;
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#endif
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};
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/* main rawmidi functions */
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int snd_rawmidi_new(struct snd_card *card, char *id, int device,
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int output_count, int input_count,
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struct snd_rawmidi **rmidi);
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void snd_rawmidi_set_ops(struct snd_rawmidi *rmidi, int stream,
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const struct snd_rawmidi_ops *ops);
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/* callbacks */
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int snd_rawmidi_receive(struct snd_rawmidi_substream *substream,
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const unsigned char *buffer, int count);
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int snd_rawmidi_transmit_empty(struct snd_rawmidi_substream *substream);
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int snd_rawmidi_transmit_peek(struct snd_rawmidi_substream *substream,
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unsigned char *buffer, int count);
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int snd_rawmidi_transmit_ack(struct snd_rawmidi_substream *substream, int count);
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int snd_rawmidi_transmit(struct snd_rawmidi_substream *substream,
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unsigned char *buffer, int count);
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int __snd_rawmidi_transmit_peek(struct snd_rawmidi_substream *substream,
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unsigned char *buffer, int count);
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int __snd_rawmidi_transmit_ack(struct snd_rawmidi_substream *substream,
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int count);
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/* main midi functions */
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int snd_rawmidi_info_select(struct snd_card *card, struct snd_rawmidi_info *info);
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int snd_rawmidi_kernel_open(struct snd_card *card, int device, int subdevice,
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int mode, struct snd_rawmidi_file *rfile);
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int snd_rawmidi_kernel_release(struct snd_rawmidi_file *rfile);
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int snd_rawmidi_output_params(struct snd_rawmidi_substream *substream,
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struct snd_rawmidi_params *params);
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int snd_rawmidi_input_params(struct snd_rawmidi_substream *substream,
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struct snd_rawmidi_params *params);
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int snd_rawmidi_drop_output(struct snd_rawmidi_substream *substream);
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int snd_rawmidi_drain_output(struct snd_rawmidi_substream *substream);
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int snd_rawmidi_drain_input(struct snd_rawmidi_substream *substream);
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long snd_rawmidi_kernel_read(struct snd_rawmidi_substream *substream,
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unsigned char *buf, long count);
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long snd_rawmidi_kernel_write(struct snd_rawmidi_substream *substream,
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const unsigned char *buf, long count);
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#endif /* __SOUND_RAWMIDI_H */
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