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5803b02388
The event handler in the virmidi sequencer code takes a read-lock for the linked list traverse, while it's calling snd_seq_dump_var_event() in the loop. The latter function may expand the user-space data depending on the event type. It eventually invokes copy_from_user(), which might be a potential dead-lock. The sequencer core guarantees that the user-space data is passed only with atomic=0 argument, but snd_virmidi_dev_receive_event() ignores it and always takes read-lock(). For avoiding the problem above, this patch introduces rwsem for non-atomic case, while keeping rwlock for atomic case. Also while we're at it: the superfluous irq flags is dropped in snd_virmidi_input_open(). Reported-by: Jia-Ju Bai <baijiaju1990@163.com> Cc: <stable@vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de>
83 lines
2.7 KiB
C
83 lines
2.7 KiB
C
#ifndef __SOUND_SEQ_VIRMIDI_H
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#define __SOUND_SEQ_VIRMIDI_H
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/*
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* Virtual Raw MIDI client on Sequencer
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* Copyright (c) 2000 by Takashi Iwai <tiwai@suse.de>,
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* Jaroslav Kysela <perex@perex.cz>
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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/rawmidi.h>
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#include <sound/seq_midi_event.h>
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/*
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* device file instance:
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* This instance is created at each time the midi device file is
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* opened. Each instance has its own input buffer and MIDI parser
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* (buffer), and is associated with the device instance.
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*/
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struct snd_virmidi {
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struct list_head list;
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int seq_mode;
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int client;
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int port;
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unsigned int trigger: 1;
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struct snd_midi_event *parser;
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struct snd_seq_event event;
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struct snd_virmidi_dev *rdev;
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struct snd_rawmidi_substream *substream;
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};
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#define SNDRV_VIRMIDI_SUBSCRIBE (1<<0)
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#define SNDRV_VIRMIDI_USE (1<<1)
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/*
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* device record:
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* Each virtual midi device has one device instance. It contains
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* common information and the linked-list of opened files,
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*/
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struct snd_virmidi_dev {
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struct snd_card *card; /* associated card */
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struct snd_rawmidi *rmidi; /* rawmidi device */
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int seq_mode; /* SNDRV_VIRMIDI_XXX */
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int device; /* sequencer device */
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int client; /* created/attached client */
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int port; /* created/attached port */
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unsigned int flags; /* SNDRV_VIRMIDI_* */
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rwlock_t filelist_lock;
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struct rw_semaphore filelist_sem;
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struct list_head filelist;
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};
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/* sequencer mode:
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* ATTACH = input/output events from midi device are routed to the
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* attached sequencer port. sequencer port is not created
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* by virmidi itself.
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* the input to rawmidi must be processed by passing the
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* incoming events via snd_virmidi_receive()
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* DISPATCH = input/output events are routed to subscribers.
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* sequencer port is created in virmidi.
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*/
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#define SNDRV_VIRMIDI_SEQ_NONE 0
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#define SNDRV_VIRMIDI_SEQ_ATTACH 1
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#define SNDRV_VIRMIDI_SEQ_DISPATCH 2
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int snd_virmidi_new(struct snd_card *card, int device, struct snd_rawmidi **rrmidi);
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#endif /* __SOUND_SEQ_VIRMIDI */
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