ALSA: line6: use dynamic buffers

The line6 driver uses a lot of USB buffers off of the stack, which is
not allowed on many systems, causing the driver to crash on some of
them.  Fix this up by dynamically allocating the buffers with kmalloc()
which allows for proper DMA-able memory.

Reported-by: Christo Gouws <gouws.christo@gmail.com>
Reported-by: Alan Stern <stern@rowland.harvard.edu>
Tested-by: Christo Gouws <gouws.christo@gmail.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 35 insertions, 25 deletions

diff --git a/sound/usb/line6/driver.c b/sound/usb/line6/driver.c
index 7afe8fae4939..b61f65bed4e4 100644
--- a/sound/usb/line6/driver.c
+++ b/sound/usb/line6/driver.c
@@ -351,12 +351,16 @@ int line6_read_data(struct usb_line6 *line6, unsigned address, void *data,
 {
 	struct usb_device *usbdev = line6->usbdev;
 	int ret;
-	unsigned char len;
+	unsigned char *len;
 	unsigned count;
 
 	if (address > 0xffff || datalen > 0xff)
 		return -EINVAL;
 
+	len = kmalloc(sizeof(*len), GFP_KERNEL);
+	if (!len)
+		return -ENOMEM;
+
 	/* query the serial number: */
 	ret = usb_control_msg(usbdev, usb_sndctrlpipe(usbdev, 0), 0x67,
 			      USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
@@ -365,7 +369,7 @@ int line6_read_data(struct usb_line6 *line6, unsigned address, void *data,
 
 	if (ret < 0) {
 		dev_err(line6->ifcdev, "read request failed (error %d)\n", ret);
-		return ret;
+		goto exit;
 	}
 
 	/* Wait for data length. We'll get 0xff until length arrives. */
@@ -375,28 +379,29 @@ int line6_read_data(struct usb_line6 *line6, unsigned address, void *data,
 		ret = usb_control_msg(usbdev, usb_rcvctrlpipe(usbdev, 0), 0x67,
 				      USB_TYPE_VENDOR | USB_RECIP_DEVICE |
 				      USB_DIR_IN,
-				      0x0012, 0x0000, &len, 1,
+				      0x0012, 0x0000, len, 1,
 				      LINE6_TIMEOUT * HZ);
 		if (ret < 0) {
 			dev_err(line6->ifcdev,
 				"receive length failed (error %d)\n", ret);
-			return ret;
+			goto exit;
 		}
 
-		if (len != 0xff)
+		if (*len != 0xff)
 			break;
 	}
 
-	if (len == 0xff) {
+	ret = -EIO;
+	if (*len == 0xff) {
 		dev_err(line6->ifcdev, "read failed after %d retries\n",
 			count);
-		return -EIO;
-	} else if (len != datalen) {
+		goto exit;
+	} else if (*len != datalen) {
 		/* should be equal or something went wrong */
 		dev_err(line6->ifcdev,
 			"length mismatch (expected %d, got %d)\n",
-			(int)datalen, (int)len);
-		return -EIO;
+			(int)datalen, (int)*len);
+		goto exit;
 	}
 
 	/* receive the result: */
@@ -405,12 +410,12 @@ int line6_read_data(struct usb_line6 *line6, unsigned address, void *data,
 			      0x0013, 0x0000, data, datalen,
 			      LINE6_TIMEOUT * HZ);
 
-	if (ret < 0) {
+	if (ret < 0)
 		dev_err(line6->ifcdev, "read failed (error %d)\n", ret);
-		return ret;
-	}
 
-	return 0;
+exit:
+	kfree(len);
+	return ret;
 }
 EXPORT_SYMBOL_GPL(line6_read_data);
 
@@ -422,12 +427,16 @@ int line6_write_data(struct usb_line6 *line6, unsigned address, void *data,
 {
 	struct usb_device *usbdev = line6->usbdev;
 	int ret;
-	unsigned char status;
+	unsigned char *status;
 	int count;
 
 	if (address > 0xffff || datalen > 0xffff)
 		return -EINVAL;
 
+	status = kmalloc(sizeof(*status), GFP_KERNEL);
+	if (!status)
+		return -ENOMEM;
+
 	ret = usb_control_msg(usbdev, usb_sndctrlpipe(usbdev, 0), 0x67,
 			      USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
 			      0x0022, address, data, datalen,
@@ -436,7 +445,7 @@ int line6_write_data(struct usb_line6 *line6, unsigned address, void *data,
 	if (ret < 0) {
 		dev_err(line6->ifcdev,
 			"write request failed (error %d)\n", ret);
-		return ret;
+		goto exit;
 	}
 
 	for (count = 0; count < LINE6_READ_WRITE_MAX_RETRIES; count++) {
@@ -447,28 +456,29 @@ int line6_write_data(struct usb_line6 *line6, unsigned address, void *data,
 				      USB_TYPE_VENDOR | USB_RECIP_DEVICE |
 				      USB_DIR_IN,
 				      0x0012, 0x0000,
-				      &status, 1, LINE6_TIMEOUT * HZ);
+				      status, 1, LINE6_TIMEOUT * HZ);
 
 		if (ret < 0) {
 			dev_err(line6->ifcdev,
 				"receiving status failed (error %d)\n", ret);
-			return ret;
+			goto exit;
 		}
 
-		if (status != 0xff)
+		if (*status != 0xff)
 			break;
 	}
 
-	if (status == 0xff) {
+	if (*status == 0xff) {
 		dev_err(line6->ifcdev, "write failed after %d retries\n",
 			count);
-		return -EIO;
-	} else if (status != 0) {
+		ret = -EIO;
+	} else if (*status != 0) {
 		dev_err(line6->ifcdev, "write failed (error %d)\n", ret);
-		return -EIO;
+		ret = -EIO;
 	}
-
-	return 0;
+exit:
+	kfree(status);
+	return ret;
 }
 EXPORT_SYMBOL_GPL(line6_write_data);