Hi Yong,
> -----Original Message-----
> From: Zhi, Yong
> Sent: Wednesday, January 03, 2018 6:57 PM
> To: linux-media@xxxxxxxxxxxxxxx; sakari.ailus@xxxxxxxxxxxxxxx
> Cc: tfiga@xxxxxxxxxxxx; Mani, Rajmohan <rajmohan.mani@xxxxxxxxx>; Zhi,
> Yong <yong.zhi@xxxxxxxxx>; Cao, Bingbu <bingbu.cao@xxxxxxxxx>
> Subject: [PATCH 1/2] media: intel-ipu3: cio2: fix a crash with out-of-bounds
> access
>
> When dmabuf is used for BLOB type frame, the frame buffers allocated by
> gralloc will hold more pages than the valid frame data due to height alignment.
>
> In this case, the page numbers in sg list could exceed the FBPT upper limit
> value - max_lops(8)*1024 to cause crash.
>
> Limit the LOP access to the valid data length to avoid FBPT sub-entries
> overflow.
>
> Signed-off-by: Yong Zhi <yong.zhi@xxxxxxxxx>
> Signed-off-by: Cao Bing Bu <bingbu.cao@xxxxxxxxx>
> ---
> drivers/media/pci/intel/ipu3/ipu3-cio2.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/media/pci/intel/ipu3/ipu3-cio2.c
> b/drivers/media/pci/intel/ipu3/ipu3-cio2.c
> index 941caa987dab..949f43d206ad 100644
> --- a/drivers/media/pci/intel/ipu3/ipu3-cio2.c
> +++ b/drivers/media/pci/intel/ipu3/ipu3-cio2.c
> @@ -838,8 +838,9 @@ static int cio2_vb2_buf_init(struct vb2_buffer *vb)
> container_of(vb, struct cio2_buffer, vbb.vb2_buf);
> static const unsigned int entries_per_page =
> CIO2_PAGE_SIZE / sizeof(u32);
> - unsigned int pages = DIV_ROUND_UP(vb->planes[0].length,
> CIO2_PAGE_SIZE);
> - unsigned int lops = DIV_ROUND_UP(pages + 1, entries_per_page);
> + unsigned int pages = DIV_ROUND_UP(vb->planes[0].length,
> + CIO2_PAGE_SIZE) + 1;
> + unsigned int lops = DIV_ROUND_UP(pages, entries_per_page);
> struct sg_table *sg;
> struct sg_page_iter sg_iter;
> int i, j;
> @@ -869,6 +870,8 @@ static int cio2_vb2_buf_init(struct vb2_buffer *vb)
>
> i = j = 0;
Nit: separate assignments are preferred over multiple assignments
> for_each_sg_page(sg->sgl, &sg_iter, sg->nents, 0) {
> + if (!pages--)
> + break;
> b->lop[i][j] = sg_page_iter_dma_address(&sg_iter) >>
> PAGE_SHIFT;
> j++;
> if (j == entries_per_page) {
> --
> 2.7.4
