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-Url: https://git.stricted.de/?a=commitdiff_plain;h=a0ac402cfcdc904f9772e1762b3fda112dcc56a0;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git

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

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>
---

diff --git a/block/blk-map.c b/block/blk-map.c
index b8657fa8dc9a..27fd8d92892d 100644
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -118,6 +118,9 @@ int blk_rq_map_user_iov(struct request_queue *q, struct request *rq,
 	struct iov_iter i;
 	int ret;
 
+	if (!iter_is_iovec(iter))
+		goto fail;
+
 	if (map_data)
 		copy = true;
 	else if (iov_iter_alignment(iter) & align)
@@ -140,6 +143,7 @@ int blk_rq_map_user_iov(struct request_queue *q, struct request *rq,
 
 unmap_rq:
 	__blk_rq_unmap_user(bio);
+fail:
 	rq->bio = NULL;
 	return -EINVAL;
 }