[PATCH v2 1/3] videobuf2-core: Prevent size alignment wrapping buffer size to 0

[Sakari Ailus <sakari.ailus@linux.intel.com>]

PAGE_ALIGN() may wrap the buffer size around to 0. Prevent this by
checking that the aligned value is not smaller than the unaligned one.

Note on backporting to stable: the file used to be under
drivers/media/v4l2-core, it was moved to the current location after 4.14.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: stable@vger.kernel.org
Reviewed-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
---
 drivers/media/common/videobuf2/videobuf2-core.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
index 0ca81d495bda..0234ddbfa4de 100644
--- a/drivers/media/common/videobuf2/videobuf2-core.c
+++ b/drivers/media/common/videobuf2/videobuf2-core.c
@@ -207,6 +207,10 @@ static int __vb2_buf_mem_alloc(struct vb2_buffer *vb)
 	for (plane = 0; plane < vb->num_planes; ++plane) {
 		unsigned long size = PAGE_ALIGN(vb->planes[plane].length);
 
+		/* Did it wrap around? */
+		if (size < vb->planes[plane].length)
+			goto free;
+
 		mem_priv = call_ptr_memop(vb, alloc,
 				q->alloc_devs[plane] ? : q->dev,
 				q->dma_attrs, size, q->dma_dir, q->gfp_flags);
-- 
2.11.0