[PATCH 2/5] staging: comedi: usbdux: Split a condition check in usbdux_alloc_usb_buffers()

[SF Markus Elfring <elfring@users.sourceforge.net>]

From: Markus Elfring <elfring@users.sourceforge.net>
Date: Thu, 8 Dec 2016 10:01:54 +0100

The functions "kcalloc" and "kzalloc" were called in four cases by the
function "usbdux_alloc_usb_buffers" without checking immediately
if they succeded.
This issue was detected by using the Coccinelle software.

Allocated memory was also not released if one of these function
calls failed.

* Split a condition check for memory allocation failures.

* Add more exception handling.

Fixes: ef1e3c4a3b383c6da3979670fcb5c6e9c7de4741 ("staging: comedi: usbdux: tidy up usbdux_alloc_usb_buffers()")

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
---
 drivers/staging/comedi/drivers/usbdux.c | 53 ++++++++++++++++++++++++++-------
 1 file changed, 43 insertions(+), 10 deletions(-)

diff --git a/drivers/staging/comedi/drivers/usbdux.c b/drivers/staging/comedi/drivers/usbdux.c
index f4f05d29d30d..d7d683bd669c 100644
--- a/drivers/staging/comedi/drivers/usbdux.c
+++ b/drivers/staging/comedi/drivers/usbdux.c
@@ -1449,24 +1449,35 @@ static int usbdux_alloc_usb_buffers(struct comedi_device *dev)
 	struct usb_device *usb = comedi_to_usb_dev(dev);
 	struct usbdux_private *devpriv = dev->private;
 	struct urb *urb;
-	int i;
+	int i, x;
 
 	devpriv->dux_commands = kzalloc(SIZEOFDUXBUFFER, GFP_KERNEL);
+	if (!devpriv->dux_commands)
+		return -ENOMEM;
+
 	devpriv->in_buf = kzalloc(SIZEINBUF, GFP_KERNEL);
+	if (!devpriv->in_buf)
+		goto free_commands;
+
 	devpriv->insn_buf = kzalloc(SIZEINSNBUF, GFP_KERNEL);
+	if (!devpriv->insn_buf)
+		goto free_in_buf;
+
 	devpriv->ai_urbs = kcalloc(devpriv->n_ai_urbs, sizeof(void *),
 				   GFP_KERNEL);
+	if (!devpriv->ai_urbs)
+		goto free_insn_buf;
+
 	devpriv->ao_urbs = kcalloc(devpriv->n_ao_urbs, sizeof(void *),
 				   GFP_KERNEL);
-	if (!devpriv->dux_commands || !devpriv->in_buf || !devpriv->insn_buf ||
-	    !devpriv->ai_urbs || !devpriv->ao_urbs)
-		return -ENOMEM;
+	if (!devpriv->ao_urbs)
+		goto free_ai_urbs;
 
 	for (i = 0; i < devpriv->n_ai_urbs; i++) {
 		/* one frame: 1ms */
 		urb = usb_alloc_urb(1, GFP_KERNEL);
 		if (!urb)
-			return -ENOMEM;
+			goto free_n_ai_urbs;
 		devpriv->ai_urbs[i] = urb;
 
 		urb->dev = usb;
@@ -1475,7 +1486,7 @@ static int usbdux_alloc_usb_buffers(struct comedi_device *dev)
 		urb->transfer_flags = URB_ISO_ASAP;
 		urb->transfer_buffer = kzalloc(SIZEINBUF, GFP_KERNEL);
 		if (!urb->transfer_buffer)
-			return -ENOMEM;
+			goto free_n_ai_urbs;
 
 		urb->complete = usbduxsub_ai_isoc_irq;
 		urb->number_of_packets = 1;
@@ -1488,7 +1499,7 @@ static int usbdux_alloc_usb_buffers(struct comedi_device *dev)
 		/* one frame: 1ms */
 		urb = usb_alloc_urb(1, GFP_KERNEL);
 		if (!urb)
-			return -ENOMEM;
+			goto free_n_ao_urbs;
 		devpriv->ao_urbs[i] = urb;
 
 		urb->dev = usb;
@@ -1497,7 +1508,7 @@ static int usbdux_alloc_usb_buffers(struct comedi_device *dev)
 		urb->transfer_flags = URB_ISO_ASAP;
 		urb->transfer_buffer = kzalloc(SIZEOUTBUF, GFP_KERNEL);
 		if (!urb->transfer_buffer)
-			return -ENOMEM;
+			goto free_n_ao_urbs;
 
 		urb->complete = usbduxsub_ao_isoc_irq;
 		urb->number_of_packets = 1;
@@ -1514,17 +1525,39 @@ static int usbdux_alloc_usb_buffers(struct comedi_device *dev)
 	if (devpriv->pwm_buf_sz) {
 		urb = usb_alloc_urb(0, GFP_KERNEL);
 		if (!urb)
-			return -ENOMEM;
+			goto free_n_ao_urbs;
 		devpriv->pwm_urb = urb;
 
 		/* max bulk ep size in high speed */
 		urb->transfer_buffer = kzalloc(devpriv->pwm_buf_sz,
 					       GFP_KERNEL);
 		if (!urb->transfer_buffer)
-			return -ENOMEM;
+			goto free_pwm_urb;
 	}
 
 	return 0;
+free_pwm_urb:
+	usb_free_urb(urb);
+free_n_ao_urbs:
+	for (x = 0; x < i; ++x) {
+		kfree(devpriv->ao_urbs[x]->transfer_buffer);
+		usb_free_urb(devpriv->ao_urbs[x]);
+	}
+free_n_ai_urbs:
+	for (x = 0; x < i; ++x) {
+		kfree(devpriv->ai_urbs[x]->transfer_buffer);
+		usb_free_urb(devpriv->ai_urbs[x]);
+	}
+	kfree(devpriv->ao_urbs);
+free_ai_urbs:
+	kfree(devpriv->ai_urbs);
+free_insn_buf:
+	kfree(devpriv->insn_buf);
+free_in_buf:
+	kfree(devpriv->in_buf);
+free_commands:
+	kfree(devpriv->dux_commands);
+	return -ENOMEM;
 }
 
 static void usbdux_free_usb_buffers(struct comedi_device *dev)
-- 
2.11.0