From: Mateusz Guzik <mjguzik@gmail.com>
To: Jan Kara <jack@suse.cz>
Cc: syzbot <syzbot+6ec38f7a8db3b3fb1002@syzkaller.appspotmail.com>,
almaz.alexandrovich@paragon-software.com, anton@tuxera.com,
axboe@kernel.dk, brauner@kernel.org, ebiederm@xmission.com,
keescook@chromium.org, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
linux-ntfs-dev@lists.sourceforge.net, ntfs3@lists.linux.dev,
syzkaller-bugs@googlegroups.com, tytso@mit.edu,
viro@zeniv.linux.org.uk, willy@infradead.org
Subject: Re: [syzbot] [ntfs3?] WARNING in do_open_execat
Date: Tue, 12 Mar 2024 13:44:07 +0100 [thread overview]
Message-ID: <CAGudoHGLLbXxxEyeOQxecL5Cj21rFgMo1QFGYntF+aNEKyJ=rQ@mail.gmail.com> (raw)
In-Reply-To: <20240312120658.os72hvnk5jedwbaw@quack3>
On 3/12/24, Jan Kara <jack@suse.cz> wrote:
> On Mon 11-03-24 20:01:14, Mateusz Guzik wrote:
>> On 3/11/24, Jan Kara <jack@suse.cz> wrote:
>> > On Mon 11-03-24 11:04:04, syzbot wrote:
>> >> syzbot suspects this issue was fixed by commit:
>> >>
>> >> commit 6f861765464f43a71462d52026fbddfc858239a5
>> >> Author: Jan Kara <jack@suse.cz>
>> >> Date: Wed Nov 1 17:43:10 2023 +0000
>> >>
>> >> fs: Block writes to mounted block devices
>> >>
>> >> bisection log:
>> >> https://syzkaller.appspot.com/x/bisect.txt?x=17e3f58e180000
>> >> start commit: eb3479bc23fa Merge tag 'kbuild-fixes-v6.7' of
>> >> git://git.ke..
>> >> git tree: upstream
>> >> kernel config:
>> >> https://syzkaller.appspot.com/x/.config?x=bdf178b2f20f99b0
>> >> dashboard link:
>> >> https://syzkaller.appspot.com/bug?extid=6ec38f7a8db3b3fb1002
>> >> syz repro:
>> >> https://syzkaller.appspot.com/x/repro.syz?x=15073fd4e80000
>> >> C reproducer:
>> >> https://syzkaller.appspot.com/x/repro.c?x=17b20b8f680000
>> >>
>> >> If the result looks correct, please mark the issue as fixed by
>> >> replying
>> >> with:
>> >
>> > #syz fix: fs: Block writes to mounted block devices
>> >
>>
>> I don't think that's correct.
>>
>> The bug is ntfs instantiating an inode with bogus type (based on an
>> intentionally corrupted filesystem), violating the api contract with
>> vfs, which in turn results in the warning way later.
>>
>> It may be someone sorted out ntfs doing this in the meantime, I have
>> not checked.
>>
>> With this in mind I don't believe your patch fixed it, at best it
>> happened to neuter the reproducer.
>
> OK, I didn't dig deep into the bug. I've just seen there are no working
> reproducers and given this is ntfs3 which doesn't really have great
> maintenance effort put into it, I've opted for closing the bug. If there's
> a way to tickle the bug without writing to mounted block device, syzbot
> should eventually find it and create a new issue... But if you want to look
> into this feel free to :) Thanks for sharing the info.
>
Maybe I'll get around to future-proofing by adding validation before
the inode escapes the filesystem code, but I'm definitely NOT patching
ntfs. 8->
--
Mateusz Guzik <mjguzik gmail.com>
prev parent reply other threads:[~2024-03-12 12:44 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <000000000000c74d44060334d476@google.com>
2024-03-11 18:04 ` [syzbot] [ntfs3?] WARNING in do_open_execat syzbot
2024-03-11 18:48 ` Jan Kara
2024-03-11 19:01 ` Mateusz Guzik
2024-03-12 12:06 ` Jan Kara
2024-03-12 12:44 ` Mateusz Guzik [this message]
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