DivestOS/Patches/Linux_CVEs/CVE-2016-9576/ANY/0003.patch

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From a0ac402cfcdc904f9772e1762b3fda112dcc56a0 Mon Sep 17 00:00:00 2001
From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Tue, 6 Dec 2016 16:18:14 -0800
Subject: [PATCH] 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>
---
block/blk-map.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/block/blk-map.c b/block/blk-map.c
index b8657fa8dc9af..27fd8d92892d4 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;
}