From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Wed, 7 Dec 2016 00:18:14 +0000 (-0800)
Subject: Don't feed anything but regular iovec's to blk_rq_map_user_iov
X-Git-Tag: firefly_0821_release~176^2~4^2~9^2~5
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=d41fb2fbb28d3a1085960edada6c046becd1fafd;p=firefly-linux-kernel-4.4.55.git

Don't feed anything but regular iovec's to blk_rq_map_user_iov

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@suse.de>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/block/blk-map.c b/block/blk-map.c
index f565e11f465a..69953bd97e65 100644
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -90,6 +90,9 @@ int blk_rq_map_user_iov(struct request_queue *q, struct request *rq,
 	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;