[PATCH 4.4 23/28] Dont feed anything but regular iovecs to blk_rq_map_user_iov

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>

commit a0ac402cfcdc904f9772e1762b3fda112dcc56a0 upstream.

In theory we could map other things, but there's a reason that function
is called "user_iov".  Using anything else (like splice can do) just
confuses it.

Reported-and-tested-by: Johannes Thumshirn <jthumshirn@xxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 block/blk-map.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -90,6 +90,9 @@ int blk_rq_map_user_iov(struct request_q
 	if (!iter || !iter->count)
 		return -EINVAL;
 
+	if (!iter_is_iovec(iter))
+		return -EINVAL;
+
 	iov_for_each(iov, i, *iter) {
 		unsigned long uaddr = (unsigned long) iov.iov_base;