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

From: Greg Kroah-Hartman
Date: Fri Dec 09 2016 - 11:18:58 EST

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;