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Subject: Re: [PATCH] jffs2: free jffs2_sb_info through jffs2_kill_sb()
To:     Richard Weinberger <richard.weinberger@gmail.com>
CC:     "linux-mtd @ lists . infradead . org" <linux-mtd@lists.infradead.org>,
        LKML <linux-kernel@vger.kernel.org>,
        David Woodhouse <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>
 <6401cb90-a1fe-afd5-c302-ddae40876736@huawei.com>
 <CAFLxGvw+=gfrm3SH4Hu9bt0sa6s+X=3cCjkDLvWusqhHH10yEQ@mail.gmail.com>
From:   Hou Tao <houtao1@huawei.com>
Message-ID: <9bb38d45-41c7-9f16-bf6b-d21ba6617f1c@huawei.com>
Date:   Tue, 16 Oct 2018 18:26:34 +0800
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On 2018/10/16 14:41, Richard Weinberger wrote:
> On Tue, Oct 16, 2018 at 7:53 AM Hou Tao <houtao1@huawei.com> wrote:
>>
>> 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;
>>> -     }
> 
> Reviewed-by: Richard Weinberger <richard@nod.at>
> 
> We can carry this via the MTD tree.
Thanks for that.

Regards,
Tao