[PATCH 1/2] ALSA: vx: Fix possible transfer overflow

[PATCH 1/2] ALSA: vx: Fix possible transfer overflow

[Takashi Iwai]

The pseudo DMA transfer codes in VX222 and VX-pocket driver have a
slight bug where they check the buffer boundary wrongly, and may
overflow.  Also, the zero sample count might be handled badly for the
playback (although it shouldn't happen in theory).  This patch
addresses these issues.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=141541
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 sound/drivers/vx/vx_pcm.c   |  6 ++++--
 sound/pci/vx222/vx222_ops.c | 12 ++++++------
 sound/pcmcia/vx/vxp_ops.c   | 12 ++++++------
 3 files changed, 16 insertions(+), 14 deletions(-)

diff --git a/sound/drivers/vx/vx_pcm.c b/sound/drivers/vx/vx_pcm.c
index 11467272089e..41a617886cc7 100644
--- a/sound/drivers/vx/vx_pcm.c
+++ b/sound/drivers/vx/vx_pcm.c
@@ -1048,8 +1048,10 @@ static void vx_pcm_capture_update(struct vx_core *chip, struct snd_pcm_substream
 		/* ok, let's accelerate! */
 		int align = pipe->align * 3;
 		space = (count / align) * align;
-		vx_pseudo_dma_read(chip, runtime, pipe, space);
-		count -= space;
+		if (space > 0) {
+			vx_pseudo_dma_read(chip, runtime, pipe, space);
+			count -= space;
+		}
 	}
 	/* read the rest of bytes */
 	while (count > 0) {
diff --git a/sound/pci/vx222/vx222_ops.c b/sound/pci/vx222/vx222_ops.c
index af83b3b38052..8e457ea27f89 100644
--- a/sound/pci/vx222/vx222_ops.c
+++ b/sound/pci/vx222/vx222_ops.c
@@ -269,12 +269,12 @@ static void vx2_dma_write(struct vx_core *chip, struct snd_pcm_runtime *runtime,
 
 	/* Transfer using pseudo-dma.
 	 */
-	if (offset + count > pipe->buffer_bytes) {
+	if (offset + count >= pipe->buffer_bytes) {
 		int length = pipe->buffer_bytes - offset;
 		count -= length;
 		length >>= 2; /* in 32bit words */
 		/* Transfer using pseudo-dma. */
-		while (length-- > 0) {
+		for (; length > 0; length--) {
 			outl(cpu_to_le32(*addr), port);
 			addr++;
 		}
@@ -284,7 +284,7 @@ static void vx2_dma_write(struct vx_core *chip, struct snd_pcm_runtime *runtime,
 	pipe->hw_ptr += count;
 	count >>= 2; /* in 32bit words */
 	/* Transfer using pseudo-dma. */
-	while (count-- > 0) {
+	for (; count > 0; count--) {
 		outl(cpu_to_le32(*addr), port);
 		addr++;
 	}
@@ -307,12 +307,12 @@ static void vx2_dma_read(struct vx_core *chip, struct snd_pcm_runtime *runtime,
 	vx2_setup_pseudo_dma(chip, 0);
 	/* Transfer using pseudo-dma.
 	 */
-	if (offset + count > pipe->buffer_bytes) {
+	if (offset + count >= pipe->buffer_bytes) {
 		int length = pipe->buffer_bytes - offset;
 		count -= length;
 		length >>= 2; /* in 32bit words */
 		/* Transfer using pseudo-dma. */
-		while (length-- > 0)
+		for (; length > 0; length--)
 			*addr++ = le32_to_cpu(inl(port));
 		addr = (u32 *)runtime->dma_area;
 		pipe->hw_ptr = 0;
@@ -320,7 +320,7 @@ static void vx2_dma_read(struct vx_core *chip, struct snd_pcm_runtime *runtime,
 	pipe->hw_ptr += count;
 	count >>= 2; /* in 32bit words */
 	/* Transfer using pseudo-dma. */
-	while (count-- > 0)
+	for (; count > 0; count--)
 		*addr++ = le32_to_cpu(inl(port));
 
 	vx2_release_pseudo_dma(chip);
diff --git a/sound/pcmcia/vx/vxp_ops.c b/sound/pcmcia/vx/vxp_ops.c
index 281972913c32..56aa1ba73ccc 100644
--- a/sound/pcmcia/vx/vxp_ops.c
+++ b/sound/pcmcia/vx/vxp_ops.c
@@ -369,12 +369,12 @@ static void vxp_dma_write(struct vx_core *chip, struct snd_pcm_runtime *runtime,
 	unsigned short *addr = (unsigned short *)(runtime->dma_area + offset);
 
 	vx_setup_pseudo_dma(chip, 1);
-	if (offset + count > pipe->buffer_bytes) {
+	if (offset + count >= pipe->buffer_bytes) {
 		int length = pipe->buffer_bytes - offset;
 		count -= length;
 		length >>= 1; /* in 16bit words */
 		/* Transfer using pseudo-dma. */
-		while (length-- > 0) {
+		for (; length > 0; length--) {
 			outw(cpu_to_le16(*addr), port);
 			addr++;
 		}
@@ -384,7 +384,7 @@ static void vxp_dma_write(struct vx_core *chip, struct snd_pcm_runtime *runtime,
 	pipe->hw_ptr += count;
 	count >>= 1; /* in 16bit words */
 	/* Transfer using pseudo-dma. */
-	while (count-- > 0) {
+	for (; count > 0; count--) {
 		outw(cpu_to_le16(*addr), port);
 		addr++;
 	}
@@ -411,12 +411,12 @@ static void vxp_dma_read(struct vx_core *chip, struct snd_pcm_runtime *runtime,
 	if (snd_BUG_ON(count % 2))
 		return;
 	vx_setup_pseudo_dma(chip, 0);
-	if (offset + count > pipe->buffer_bytes) {
+	if (offset + count >= pipe->buffer_bytes) {
 		int length = pipe->buffer_bytes - offset;
 		count -= length;
 		length >>= 1; /* in 16bit words */
 		/* Transfer using pseudo-dma. */
-		while (length-- > 0)
+		for (; length > 0; length--)
 			*addr++ = le16_to_cpu(inw(port));
 		addr = (unsigned short *)runtime->dma_area;
 		pipe->hw_ptr = 0;
@@ -424,7 +424,7 @@ static void vxp_dma_read(struct vx_core *chip, struct snd_pcm_runtime *runtime,
 	pipe->hw_ptr += count;
 	count >>= 1; /* in 16bit words */
 	/* Transfer using pseudo-dma. */
-	while (count-- > 1)
+	for (; count > 1; count--)
 		*addr++ = le16_to_cpu(inw(port));
 	/* Disable DMA */
 	pchip->regDIALOG &= ~VXP_DLG_DMAREAD_SEL_MASK;
-- 
2.11.0

[PATCH 2/2] ALSA: vx: Don't try to update capture stream before running

[Takashi Iwai]

The update of stream costs significantly, and we should avoid it
unless the stream really has started.  Check pipe->running flag
instead of pipe->prepared.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 sound/drivers/vx/vx_pcm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/drivers/vx/vx_pcm.c b/sound/drivers/vx/vx_pcm.c
index 41a617886cc7..ea7b377f0378 100644
--- a/sound/drivers/vx/vx_pcm.c
+++ b/sound/drivers/vx/vx_pcm.c
@@ -1015,7 +1015,7 @@ static void vx_pcm_capture_update(struct vx_core *chip, struct snd_pcm_substream
 	int size, space, count;
 	struct snd_pcm_runtime *runtime = subs->runtime;
 
-	if (! pipe->prepared || (chip->chip_status & VX_STAT_IS_STALE))
+	if (!pipe->running || (chip->chip_status & VX_STAT_IS_STALE))
 		return;
 
 	size = runtime->buffer_size - snd_pcm_capture_avail(runtime);
-- 
2.11.0