Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: [syzbot] unexpected kernel reboot (5)
To:     Dmitry Vyukov <dvyukov@google.com>,
        syzbot <syzbot+6fb8ff5211d3e821398f@syzkaller.appspotmail.com>,
        Joey Jiao <joey.jiaojg@gmail.com>
Cc:     LKML <linux-kernel@vger.kernel.org>,
        syzkaller-bugs <syzkaller-bugs@googlegroups.com>
References: <000000000000b808c705c345b35d@google.com>
 <0000000000009dfd7c05c3463b32@google.com>
 <CACT4Y+ZkGw8GDs9vYzs5t7iBba+5ZRKmTnp3zXAnkOsmyWp6Rw@mail.gmail.com>
From:   Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Message-ID: <ced68605-f4b2-9daf-4832-cdf8dd8cb5de@i-love.sakura.ne.jp>
Date:   Thu, 27 May 2021 15:59:12 +0900
User-Agent: Mozilla/5.0 (Windows NT 6.3; Win64; x64; rv:78.0) Gecko/20100101
 Thunderbird/78.10.2
MIME-Version: 1.0
In-Reply-To: <CACT4Y+ZkGw8GDs9vYzs5t7iBba+5ZRKmTnp3zXAnkOsmyWp6Rw@mail.gmail.com>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 2021/05/27 15:40, Dmitry Vyukov wrote:
> The reproducer writes into /sys/power/state. I assume this is an
> intentional way to reboot a machine and we can't let the fuzzer mess
> with all sysfs files with:
> 
> openat$sysfs(fd const[AT_FDCWD], dir ptr[in, glob["/sys/**/*"]], flags
> flags[open_flags], mode flags[open_mode]) fd
> 
> +Joey, how do you deal with this?
> 

I have CaitSith LSM module ( https://caitsith.osdn.jp/#5.2 ).
Maybe we could invent a simple LSM module for excluding access to specific pseudo files?