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Commit bf8c1382 authored by Clemens Ladisch's avatar Clemens Ladisch Committed by Jaroslav Kysela
Browse files

[ALSA] seq_midi_event: fix parsing of missing data bytes 



Reorganize the encoder logic to prevent status bytes that appear where
data bytes are expected from being interpreted as data bytes.

Signed-off-by: default avatarClemens Ladisch <clemens@ladisch.de>
Signed-off-by: default avatarJaroslav Kysela <perex@suse.cz>
parent 0b664f72

sound/core/seq/seq_midi_event.c

+41 −39
Original line number Diff line number Diff line
@@ -73,22 +73,22 @@ static struct status_event_list { 
	{SNDRV_SEQ_EVENT_CHANPRESS,	 1, one_param_ctrl_event, one_param_decode},

	{SNDRV_SEQ_EVENT_PITCHBEND,	 2, pitchbend_ctrl_event, pitchbend_decode},

	/* invalid */

	{SNDRV_SEQ_EVENT_NONE,		0, NULL, NULL},

	{SNDRV_SEQ_EVENT_NONE,		-1, NULL, NULL},

	/* 0xf0 - 0xff */

	{SNDRV_SEQ_EVENT_SYSEX,		 1, NULL, NULL}, /* sysex: 0xf0 */

	{SNDRV_SEQ_EVENT_QFRAME,	 1, one_param_event, one_param_decode}, /* 0xf1 */

	{SNDRV_SEQ_EVENT_SONGPOS,	 2, songpos_event, songpos_decode}, /* 0xf2 */

	{SNDRV_SEQ_EVENT_SONGSEL,	 1, one_param_event, one_param_decode}, /* 0xf3 */

	{SNDRV_SEQ_EVENT_NONE,		0, NULL, NULL}, /* 0xf4 */

	{SNDRV_SEQ_EVENT_NONE,		0, NULL, NULL}, /* 0xf5 */

	{SNDRV_SEQ_EVENT_NONE,		-1, NULL, NULL}, /* 0xf4 */

	{SNDRV_SEQ_EVENT_NONE,		-1, NULL, NULL}, /* 0xf5 */

	{SNDRV_SEQ_EVENT_TUNE_REQUEST,	 0, NULL, NULL}, /* 0xf6 */

	{SNDRV_SEQ_EVENT_NONE,		0, NULL, NULL}, /* 0xf7 */

	{SNDRV_SEQ_EVENT_NONE,		-1, NULL, NULL}, /* 0xf7 */

	{SNDRV_SEQ_EVENT_CLOCK,		 0, NULL, NULL}, /* 0xf8 */

	{SNDRV_SEQ_EVENT_NONE,		0, NULL, NULL}, /* 0xf9 */

	{SNDRV_SEQ_EVENT_NONE,		-1, NULL, NULL}, /* 0xf9 */

	{SNDRV_SEQ_EVENT_START,		 0, NULL, NULL}, /* 0xfa */

	{SNDRV_SEQ_EVENT_CONTINUE,	 0, NULL, NULL}, /* 0xfb */

	{SNDRV_SEQ_EVENT_STOP, 		 0, NULL, NULL}, /* 0xfc */

	{SNDRV_SEQ_EVENT_NONE, 		0, NULL, NULL}, /* 0xfd */

	{SNDRV_SEQ_EVENT_NONE, 		-1, NULL, NULL}, /* 0xfd */

	{SNDRV_SEQ_EVENT_SENSING, 	 0, NULL, NULL}, /* 0xfe */

	{SNDRV_SEQ_EVENT_RESET, 	 0, NULL, NULL}, /* 0xff */

};
@@ -256,25 +256,27 @@ int snd_midi_event_encode_byte(struct snd_midi_event *dev, int c, 
	}



	spin_lock_irqsave(&dev->lock, flags);

	if (dev->qlen > 0) {

		/* rest of command */

		dev->buf[dev->read++] = c;

		if (dev->type != ST_SYSEX)

			dev->qlen--;

	} else {

	if ((c & 0x80) &&

	    (c != MIDI_CMD_COMMON_SYSEX_END || dev->type != ST_SYSEX)) {

		/* new command */

		dev->read = 1;

		if (c & 0x80) {

		dev->buf[0] = c;

			if ((c & 0xf0) == 0xf0) /* special events */

		if ((c & 0xf0) == 0xf0) /* system messages */

			dev->type = (c & 0x0f) + ST_SPECIAL;

		else

			dev->type = (c >> 4) & 0x07;

		dev->read = 1;

		dev->qlen = status_event[dev->type].qlen;

	} else {

			/* process this byte as argument */

		if (dev->qlen > 0) {

			/* rest of command */

			dev->buf[dev->read++] = c;

			if (dev->type != ST_SYSEX)

				dev->qlen--;

		} else {

			/* running status */

			dev->buf[1] = c;

			dev->qlen = status_event[dev->type].qlen - 1;

			dev->read = 2;

		}

	}

	if (dev->qlen == 0) {