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Subject: Re: [PATCH] jffs2: free jffs2_sb_info through jffs2_kill_sb()
From:   Hou Tao <houtao1@huawei.com>
To:     <linux-mtd@lists.infradead.org>, <linux-kernel@vger.kernel.org>
CC:     <dwmw2@infradead.org>, <stable@kernel.org>,
        Arnd Bergmann <arnd@arndb.de>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Brian Norris <computersforpeace@gmail.com>
References: <20181006090935.41714-1-houtao1@huawei.com>
Message-ID: <6401cb90-a1fe-afd5-c302-ddae40876736@huawei.com>
Date:   Tue, 16 Oct 2018 13:52:59 +0800
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ping ?

On 2018/10/6 17:09, Hou Tao wrote:
> 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.
> 
> Cc: stable@kernel.org
> Signed-off-by: Hou Tao <houtao1@huawei.com>
> ---
>  fs/jffs2/super.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/fs/jffs2/super.c b/fs/jffs2/super.c
> index 87bdf0f4cba1..902a7dd10e5c 100644
> --- a/fs/jffs2/super.c
> +++ b/fs/jffs2/super.c
> @@ -285,10 +285,8 @@ static int jffs2_fill_super(struct super_block *sb, void *data, int silent)
>  	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 */
>