[PATCH 5.1 297/371] media: videobuf2-dma-sg: Prevent size from overflowing

From: Greg Kroah-Hartman
Date: Wed Jul 24 2019 - 16:11:37 EST

From: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>

commit 14f28f5cea9e3998442de87846d1907a531b6748 upstream.

buf->size is an unsigned long; casting that to int will lead to an
overflow if buf->size exceeds INT_MAX.

Fix this by changing the type to unsigned long instead. This is possible
as the buf->size is always aligned to PAGE_SIZE, and therefore the size
will never have values lesser than 0.

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@xxxxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Reviewed-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

drivers/media/common/videobuf2/videobuf2-dma-sg.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/media/common/videobuf2/videobuf2-dma-sg.c
+++ b/drivers/media/common/videobuf2/videobuf2-dma-sg.c
@@ -59,7 +59,7 @@ static int vb2_dma_sg_alloc_compacted(st
gfp_t gfp_flags)
unsigned int last_page = 0;
- int size = buf->size;
+ unsigned long size = buf->size;

while (size > 0) {
struct page *pages;