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: NYong Zhi <yong.zhi@intel.com>
Signed-off-by: NCao Bing Bu <bingbu.cao@intel.com>
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@s-opensource.com>

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;
 	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) {