[PATCH 4/5] staging: comedi: usbduxsigma: Split a condition check in usbduxsigma_alloc_usb_buffers()

From: SF Markus Elfring
Date: Thu Dec 08 2016 - 06:38:08 EST


From: Markus Elfring <elfring@xxxxxxxxxxxxxxxxxxxxx>
Date: Thu, 8 Dec 2016 11:15:40 +0100

The functions "kcalloc" and "kzalloc" were called in four cases by the
function "usbduxsigma_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.

* Reduce memory allocation sizes for two function calls.

* Split a condition check for memory allocation failures.

* Add more exception handling.

Fixes: 65989c030bbca96be45ed137f6384dbd46030d10 ("staging: comedi: usbduxsigma: factor usb buffer allocation out of (*probe)")

Signed-off-by: Markus Elfring <elfring@xxxxxxxxxxxxxxxxxxxxx>
---
drivers/staging/comedi/drivers/usbduxsigma.c | 61 ++++++++++++++++++++++------
1 file changed, 49 insertions(+), 12 deletions(-)

diff --git a/drivers/staging/comedi/drivers/usbduxsigma.c b/drivers/staging/comedi/drivers/usbduxsigma.c
index 456e9f13becb..8c04aa5339f3 100644
--- a/drivers/staging/comedi/drivers/usbduxsigma.c
+++ b/drivers/staging/comedi/drivers/usbduxsigma.c
@@ -1341,22 +1341,37 @@ static int usbduxsigma_alloc_usb_buffers(struct comedi_device *dev)
struct usb_device *usb = comedi_to_usb_dev(dev);
struct usbduxsigma_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);
- devpriv->ai_urbs = kcalloc(devpriv->n_ai_urbs, sizeof(urb), GFP_KERNEL);
- devpriv->ao_urbs = kcalloc(devpriv->n_ao_urbs, sizeof(urb), GFP_KERNEL);
- if (!devpriv->dux_commands || !devpriv->in_buf || !devpriv->insn_buf ||
- !devpriv->ai_urbs || !devpriv->ao_urbs)
- return -ENOMEM;
+ if (!devpriv->insn_buf)
+ goto free_in_buf;
+
+ devpriv->ai_urbs = kcalloc(devpriv->n_ai_urbs,
+ sizeof(*devpriv->ai_urbs),
+ GFP_KERNEL);
+ if (!devpriv->ai_urbs)
+ goto free_insn_buf;
+
+ devpriv->ao_urbs = kcalloc(devpriv->n_ao_urbs,
+ sizeof(*devpriv->ao_urbs),
+ GFP_KERNEL);
+ 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;
/* will be filled later with a pointer to the comedi-device */
@@ -1366,7 +1381,7 @@ static int usbduxsigma_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 = usbduxsigma_ai_urb_complete;
urb->number_of_packets = 1;
urb->transfer_buffer_length = SIZEINBUF;
@@ -1378,7 +1393,7 @@ static int usbduxsigma_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;
/* will be filled later with a pointer to the comedi-device */
@@ -1388,7 +1403,7 @@ static int usbduxsigma_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 = usbduxsigma_ao_urb_complete;
urb->number_of_packets = 1;
urb->transfer_buffer_length = SIZEOUTBUF;
@@ -1400,16 +1415,38 @@ static int usbduxsigma_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;

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 usbduxsigma_free_usb_buffers(struct comedi_device *dev)
--
2.11.0