Messages in this thread | | | Date | Wed, 10 Mar 2021 10:12:22 +0200 | From | Laurent Pinchart <> | Subject | Re: [PATCH] media: videobuf2: Fix integer overrun in allocation |
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Hi Ricardo,
On Wed, Mar 10, 2021 at 08:58:39AM +0100, Ricardo Ribalda wrote: > On Wed, Mar 10, 2021 at 8:49 AM Laurent Pinchart wrote: > > On Wed, Mar 10, 2021 at 12:43:17AM +0100, 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. > > > > > > 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 | 4 +++- > > > 1 file changed, 3 insertions(+), 1 deletion(-) > > > > > > diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c > > > index 02281d13505f..543da515c761 100644 > > > --- a/drivers/media/common/videobuf2/videobuf2-core.c > > > +++ b/drivers/media/common/videobuf2/videobuf2-core.c > > > @@ -223,8 +223,10 @@ static int __vb2_buf_mem_alloc(struct vb2_buffer *vb) > > > * NOTE: mmapped areas should be page aligned > > > */ > > > for (plane = 0; plane < vb->num_planes; ++plane) { > > > + unsigned long size = vb->planes[plane].length; > > > > unsigned long is still 32-bit on 32-bit platforms. > > > > > + > > > /* Memops alloc requires size to be page aligned. */ > > > - unsigned long size = PAGE_ALIGN(vb->planes[plane].length); > > > + size = PAGE_ALIGN(size); > > > > > > /* Did it wrap around? */ > > > if (size < vb->planes[plane].length) > > > > Doesn't this address the issue already ? > > Yes and no. If you need to allocate 0xffffffff you are still affected > by the underrun. The core will return an error instead of doing the > allocation. > > (yes, I know it is a lot of memory for a buffer)
That's my point, I don't think there's a need for this :-) Especially with v4l2_buffer.m.offset being a __u32, we are limited to 4GB for *all* buffers.
-- Regards,
Laurent Pinchart
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