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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Goldwyn Rodrigues <rgoldwyn@suse.com>,
        Mike Snitzer <snitzer@redhat.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.14 125/199] dm flakey: check for null arg_name in parse_features()
Date:   Wed, 22 Apr 2020 11:57:31 +0200
Message-Id: <20200422095109.965957078@linuxfoundation.org>
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From: Goldwyn Rodrigues <rgoldwyn@suse.com>

[ Upstream commit 7690e25302dc7d0cd42b349e746fe44b44a94f2b ]

One can crash dm-flakey by specifying more feature arguments than the
number of features supplied.  Checking for null in arg_name avoids
this.

dmsetup create flakey-test --table "0 66076080 flakey /dev/sdb9 0 0 180 2 drop_writes"

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/md/dm-flakey.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/md/dm-flakey.c b/drivers/md/dm-flakey.c
index b1b68e01b889c..53cd31199f212 100644
--- a/drivers/md/dm-flakey.c
+++ b/drivers/md/dm-flakey.c
@@ -70,6 +70,11 @@ static int parse_features(struct dm_arg_set *as, struct flakey_c *fc,
 		arg_name = dm_shift_arg(as);
 		argc--;
 
+		if (!arg_name) {
+			ti->error = "Insufficient feature arguments";
+			return -EINVAL;
+		}
+
 		/*
 		 * drop_writes
 		 */
-- 
2.20.1