On Mon, Apr 6, 2020 at 4:53 PM Dan Carpenter <dan.carpenter@xxxxxxxxxx> wrote:
>
> The copy_to/from_user() functions return the number of bytes remaining
> but we want to return negative error codes. I changed a couple checks
> in raw_ioctl_ep_read() and raw_ioctl_ep0_read() to show that we still
> we returning zero on error.
>
> Fixes: f2c2e717642c ("usb: gadget: add raw-gadget interface")
> Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Thanks, Dan!
Reviewed-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Tested-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
> ---
> drivers/usb/gadget/legacy/raw_gadget.c | 46 ++++++++++++++++++++++------------------------
> 1 file changed, 22 insertions(+), 24 deletions(-)
>
> diff --git a/drivers/usb/gadget/legacy/raw_gadget.c b/drivers/usb/gadget/legacy/raw_gadget.c
> index 76406343fbe5..e490ffa1f58b 100644
> --- a/drivers/usb/gadget/legacy/raw_gadget.c
> +++ b/drivers/usb/gadget/legacy/raw_gadget.c
> @@ -392,9 +392,8 @@ static int raw_ioctl_init(struct raw_dev *dev, unsigned long value)
> char *udc_device_name;
> unsigned long flags;
>
> - ret = copy_from_user(&arg, (void __user *)value, sizeof(arg));
> - if (ret)
> - return ret;
> + if (copy_from_user(&arg, (void __user *)value, sizeof(arg)))
> + return -EFAULT;
>
> switch (arg.speed) {
> case USB_SPEED_UNKNOWN:
> @@ -501,15 +500,13 @@ static int raw_ioctl_run(struct raw_dev *dev, unsigned long value)
>
> static int raw_ioctl_event_fetch(struct raw_dev *dev, unsigned long value)
> {
> - int ret = 0;
> struct usb_raw_event arg;
> unsigned long flags;
> struct usb_raw_event *event;
> uint32_t length;
>
> - ret = copy_from_user(&arg, (void __user *)value, sizeof(arg));
> - if (ret)
> - return ret;
> + if (copy_from_user(&arg, (void __user *)value, sizeof(arg)))
> + return -EFAULT;
>
> spin_lock_irqsave(&dev->lock, flags);
> if (dev->state != STATE_DEV_RUNNING) {
> @@ -530,20 +527,19 @@ static int raw_ioctl_event_fetch(struct raw_dev *dev, unsigned long value)
> return -EINTR;
> }
> length = min(arg.length, event->length);
> - ret = copy_to_user((void __user *)value, event,
> - sizeof(*event) + length);
> - return ret;
> + if (copy_to_user((void __user *)value, event, sizeof(*event) + length))
> + return -EFAULT;
> +
> + return 0;
> }
>
> static void *raw_alloc_io_data(struct usb_raw_ep_io *io, void __user *ptr,
> bool get_from_user)
> {
> - int ret;
> void *data;
>
> - ret = copy_from_user(io, ptr, sizeof(*io));
> - if (ret)
> - return ERR_PTR(ret);
> + if (copy_from_user(io, ptr, sizeof(*io)))
> + return ERR_PTR(-EFAULT);
> if (io->ep >= USB_RAW_MAX_ENDPOINTS)
> return ERR_PTR(-EINVAL);
> if (!usb_raw_io_flags_valid(io->flags))
> @@ -658,12 +654,13 @@ static int raw_ioctl_ep0_read(struct raw_dev *dev, unsigned long value)
> if (IS_ERR(data))
> return PTR_ERR(data);
> ret = raw_process_ep0_io(dev, &io, data, false);
> - if (ret < 0) {
> - kfree(data);
> - return ret;
> - }
> + if (ret)
> + goto free;
> +
> length = min(io.length, (unsigned int)ret);
> - ret = copy_to_user((void __user *)(value + sizeof(io)), data, length);
> + if (copy_to_user((void __user *)(value + sizeof(io)), data, length))
> + ret = -EFAULT;
> +free:
> kfree(data);
> return ret;
> }
> @@ -952,12 +949,13 @@ static int raw_ioctl_ep_read(struct raw_dev *dev, unsigned long value)
> if (IS_ERR(data))
> return PTR_ERR(data);
> ret = raw_process_ep_io(dev, &io, data, false);
> - if (ret < 0) {
> - kfree(data);
> - return ret;
> - }
> + if (ret)
> + goto free;
> +
> length = min(io.length, (unsigned int)ret);
> - ret = copy_to_user((void __user *)(value + sizeof(io)), data, length);
> + if (copy_to_user((void __user *)(value + sizeof(io)), data, length))
> + ret = -EFAULT;
> +free:
> kfree(data);
> return ret;
> }
