Arjun Sreedharan wrote:
> kcalloc has protection from integer overflows
> which could arise from the multiplication of
> number of elements and size.
You are implying that such an overflow could arise in this code.
This is false.
> @@ -380,8 +380,7 @@ static int usb_parse_interface(struct device *ddev, int cfgno,
>
> if (num_ep > 0) {
> /* Can't allocate 0 bytes */
> - len = sizeof(struct usb_host_endpoint) * num_ep;
> - alt->endpoint = kzalloc(len, GFP_KERNEL);
> + alt->endpoint = kcalloc(num_ep, sizeof(struct usb_host_endpoint), GFP_KERNEL);
bNumEndpoints is an unsigned 8-bit integer.
And even if you did not notice this, you should have noticed the if()
directly before this one.
> @@ -683,13 +682,11 @@ int usb_get_configuration(struct usb_device *dev)
> return -EINVAL;
> }
>
> - length = ncfg * sizeof(struct usb_host_config);
> - dev->config = kzalloc(length, GFP_KERNEL);
> + dev->config = kcalloc(ncfg, sizeof(struct usb_host_config), GFP_KERNEL);
> if (!dev->config)
> goto err2;
>
> - length = ncfg * sizeof(char *);
> - dev->rawdescriptors = kzalloc(length, GFP_KERNEL);
> + dev->rawdescriptors = kcalloc(ncfg, sizeof(char *), GFP_KERNEL);
Same oversights here.
Regards,
Clemens
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