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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, stable@kernel.org,
        Hou Tao <houtao1@huawei.com>,
        Richard Weinberger <richard@nod.at>,
        Boris Brezillon <boris.brezillon@bootlin.com>
Subject: [PATCH 4.19 017/361] jffs2: free jffs2_sb_info through jffs2_kill_sb()
Date:   Sun, 11 Nov 2018 14:16:04 -0800
Message-Id: <20181111221622.204526777@linuxfoundation.org>
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4.19-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Hou Tao <houtao1@huawei.com>

commit 92e2921f7eee63450a5f953f4b15dc6210219430 upstream.

When an invalid mount option is passed to jffs2, jffs2_parse_options()
will fail and jffs2_sb_info will be freed, but then jffs2_sb_info will
be used (use-after-free) and freeed (double-free) in jffs2_kill_sb().

Fix it by removing the buggy invocation of kfree() when getting invalid
mount options.

Fixes: 92abc475d8de ("jffs2: implement mount option parsing and compression overriding")
Cc: stable@kernel.org
Signed-off-by: Hou Tao <houtao1@huawei.com>
Reviewed-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/jffs2/super.c |    4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

--- a/fs/jffs2/super.c
+++ b/fs/jffs2/super.c
@@ -285,10 +285,8 @@ static int jffs2_fill_super(struct super
 	sb->s_fs_info = c;
 
 	ret = jffs2_parse_options(c, data);
-	if (ret) {
-		kfree(c);
+	if (ret)
 		return -EINVAL;
-	}
 
 	/* Initialize JFFS2 superblock locks, the further initialization will
 	 * be done later */