Re: [linux-usb-devel] [PATCH] Fix a potential NULL pointer dereferencein usbat_check_status() in drivers/usb/storage/shuttle_usbat.c

From: Alan Stern
Date: Tue Sep 04 2007 - 16:59:13 EST


On Tue, 4 Sep 2007, Simon Holm Thøgersen wrote:

> > tir, 04 09 2007 kl. 13:06 +0200, skrev Jens Axboe:
> > On Tue, Sep 04 2007, Micah Gruber wrote:
> > > This patch fixes a potential null dereference bug where we dereference us before a null check. This patch simply moves the dereferencing after the null check.
> > >
> > > Signed-off-by: Micah Gruber <micah.gruber@xxxxxxxxx>
> >
> > Be careful with stuff like that, if you actually look at the code, a us
> > == NULL doesn't seem to be possible (or usbat_flash_transport() would
> > have oopsed before).
> >
> If that is true, then
> if (!us)
> return USB_STOR_TRANSPORT_ERROR;
> is utterly pointless.

Indeed, so it is.

Alan Stern

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