From: "Theodore Ts'o" <tytso@mit.edu>
To: Mateusz Guzik <mjguzik@gmail.com>
Cc: Kees Cook <kees@kernel.org>,
syzbot <syzbot+48a99e426f29859818c0@syzkaller.appspotmail.com>,
akpm@linux-foundation.org, brauner@kernel.org,
gustavoars@kernel.org, linux-hardening@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] [hardening?] [mm?] BUG: bad usercopy in vfs_readlink
Date: Wed, 5 Feb 2025 00:26:51 -0500 [thread overview]
Message-ID: <20250205052651.GD909029@mit.edu> (raw)
In-Reply-To: <CAGudoHEv+Diti3r0x9VmF5ixgRVKk4trYnX_skVJNkQoTMaDHg@mail.gmail.com>
On Tue, Feb 04, 2025 at 10:25:29PM +0100, Mateusz Guzik wrote:
> >
> > My question is if that's legitimate, I'm guessing not. If not, then
> > ext4 should complain about it.
> >
> > On stock kernel this happens to work because strlen finds the "right" size.
> >
>
> So it occurred to me to check what fsck thinks about it.
>
> I ran it twice in a row, it *removed* the problematic symlink.
Can you show me what's in the problematic symlink? And does the
syzbot reproducer trigger a problem before adding your symlink
caching?
What would be really great if you couldcreate small focused test case
that shows what's going on --- ideally something like a 100k file
system, ala the file systems in the tests directory of the e2fsprogs
sources....
- Ted
next prev parent reply other threads:[~2025-02-05 5:27 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-02-04 9:46 syzbot
2025-02-04 11:38 ` Mateusz Guzik
2025-02-04 15:30 ` Kees Cook
2025-02-04 15:58 ` Mateusz Guzik
2025-02-04 16:49 ` Mateusz Guzik
2025-02-04 20:30 ` Theodore Ts'o
2025-02-04 20:48 ` Mateusz Guzik
2025-02-04 21:25 ` Mateusz Guzik
2025-02-05 5:26 ` Theodore Ts'o [this message]
2025-02-05 12:18 ` Mateusz Guzik
2025-02-05 12:26 ` Mateusz Guzik
2025-02-05 15:20 ` syzbot
2025-02-05 18:21 ` Jan Kara
2025-02-05 18:39 ` Kees Cook
2025-02-06 9:43 ` Jan Kara
2025-02-05 18:53 ` syzbot
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