rbd: prevent bytes transferred overflow
In rbd_obj_read_sync(), verify the number of bytes transferred won't
exceed what can be represented by a size_t before using it to
indicate the number of bytes to copy to the result buffer.
(The real motivation for this is to prepare for the next patch.)
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 09514d9..93369a1 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -2048,6 +2048,7 @@
struct ceph_osd_client *osdc;
struct page **pages = NULL;
u32 page_count;
+ size_t size;
int ret;
page_count = (u32) calc_pages_for(offset, length);
@@ -2084,7 +2085,10 @@
ret = obj_request->result;
if (ret < 0)
goto out;
- ret = ceph_copy_from_page_vector(pages, buf, 0, obj_request->xferred);
+
+ rbd_assert(obj_request->xferred <= (u64) SIZE_MAX);
+ size = (size_t) obj_request->xferred;
+ ret = ceph_copy_from_page_vector(pages, buf, 0, size);
if (version)
*version = obj_request->version;
out: