Re: [PATCH] usbip: tools: Fix read_usb_vudc_device() error path handling

[Greg KH <gregkh@linuxfoundation.org>]

On Wed, Oct 16, 2019 at 01:38:25PM +0900, GwanYeong Kim wrote:
> On Tue, 15 Oct 2019 17:14:32 -0600
> shuah <shuah@kernel.org> wrote:
> 
> > On 10/15/19 7:14 AM, GwanYeong Kim wrote:
> > > cannot be less than 0 - fread() returns 0 on error.
> > > 
> > > Signed-off-by: GwanYeong Kim <gy741.kim@gmail.com>
> > > ---
> > >   tools/usb/usbip/libsrc/usbip_device_driver.c | 2 +-
> > >   1 file changed, 1 insertion(+), 1 deletion(-)
> > > 
> > > diff --git a/tools/usb/usbip/libsrc/usbip_device_driver.c
> > > b/tools/usb/usbip/libsrc/usbip_device_driver.c index
> > > 051d7d3f443b..49760b98aabc 100644 ---
> > > a/tools/usb/usbip/libsrc/usbip_device_driver.c +++
> > > b/tools/usb/usbip/libsrc/usbip_device_driver.c @@ -79,7 +79,7 @@
> > > int read_usb_vudc_device(struct udev_device *sdev, struct
> > > usbip_usb_device *dev) if (!fd) return -1;
> > >   	ret = fread((char *) &descr, sizeof(descr), 1, fd);
> > > -	if (ret < 0) > +	if (ret != sizeof(descr))
> > 
> > Are you sure this check is correct? fread() returns the number
> > of elements read, # elements = 1  in this case.
> 
> Thank you for pointing this out.
> Sorry for my mistake.
> 
> > fread() returns 0 when size or # of elements is 0 and in other
> > error cases it will return < # of elements. I would think you
> > want to check ret != 1 here.
> 
> You're right.
> This should be changed to "ret != 1".
> 
> Should I send a new patch?

If you want to have it applied, yes.

thanks,

greg k-h