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References: <20210310074028.1042475-1-ribalda@chromium.org> <48e8ffd7-7f42-8e22-bf9d-646d9bd89bd9@suse.cz>
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From:   Ricardo Ribalda <ribalda@chromium.org>
Date:   Wed, 10 Mar 2021 08:49:15 +0100
Message-ID: <CANiDSCsMo7-PR2XVpw98cF9xBifedDgWbOMFxF8HhV3E9jRRDg@mail.gmail.com>
Subject: Re: [PATCH] media: videobuf2: Fix integer overrun in vb2_mmap
To:     Jiri Slaby <jslaby@suse.cz>
Cc:     Tomasz Figa <tfiga@chromium.org>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        Linux Media Mailing List <linux-media@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Sergey Senozhatsky <senozhatsky@chromium.org>,
        stable@vger.kernel.org
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On Wed, Mar 10, 2021 at 8:47 AM Jiri Slaby <jslaby@suse.cz> wrote:
>
> On 10. 03. 21, 8:40, Ricardo Ribalda wrote:
> > The plane_length is an unsigned integer. So, if we have a size of
> > 0xffffffff bytes we incorrectly allocate 0 bytes instead of 1 << 32.
> >
> > Suggested-by: Sergey Senozhatsky <senozhatsky@chromium.org>
> > Cc: stable@vger.kernel.org
> > Fixes: 7f8414594e47 ("[media] media: videobuf2: fix the length check for mmap")
> > Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
> > ---
> >   drivers/media/common/videobuf2/videobuf2-core.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
> > index 543da515c761..876db5886867 100644
> > --- a/drivers/media/common/videobuf2/videobuf2-core.c
> > +++ b/drivers/media/common/videobuf2/videobuf2-core.c
> > @@ -2256,7 +2256,7 @@ int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma)
> >        * The buffer length was page_aligned at __vb2_buf_mem_alloc(),
> >        * so, we need to do the same here.
> >        */
> > -     length = PAGE_ALIGN(vb->planes[plane].length);
> > +     length = PAGE_ALIGN((unsigned int)vb->planes[plane].length);
>
> Hi,
>
> I fail to see how case from uint to uint helps -- IOW, did you mean ulong?

Ups... my bad :(

Let me send a v2

>
> regards,
> --
> js
> suse labs


-- 
Ricardo Ribalda