linux-kernel - Re: general protection fault in kernfs_kill

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <20180514024726.GB30522@ZenIV.linux.org.uk>
Date:   Mon, 14 May 2018 03:47:27 +0100
From:   Al Viro <viro@...IV.linux.org.uk>
To:     Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>
Cc:     syzbot <syzbot+481ad819c717f6b78df9@...kaller.appspotmail.com>,
        linux-kernel@...r.kernel.org, syzkaller-bugs@...glegroups.com,
        gregkh@...uxfoundation.org, tj@...nel.org
Subject: Re: general protection fault in kernfs_kill_sb (2)

On Sun, May 13, 2018 at 11:19:46AM +0900, Tetsuo Handa wrote:

> This is what I reported at
> https://groups.google.com/d/msg/syzkaller-bugs/ISOJlV2I2QM/qHslGMi3AwAJ .
> 
> We are currently waiting for comments from Al Viro.

1) the damn thing is unusable without javashit.  Which gets about
the same reaction as sending something.doc in attachment.  Please,
find a less obnoxious way to archive the thing (or to generate
URLs that would work without that garbage).

2) deactivate_locked_super() *WILL* be called when fill_super() fails.
Live with it; it allows to simplify a whole lot of cleanup logics
in various filesystems.  Again, we are not going for a model where
->kill_sb() is not called for something returned by sget().
Rationale: rarely exercised paths tend to rot, so anything that increases
the duplication of bits and pieces of normal teardown into failure exits
of foo_fill_super() is a bloody bad idea.  If anything, we want to take
a lot of stuff out of ->put_super() instances directly into ->kill_sb()
ones, precisely because ->put_super() is only called for fully set up
filesystems.

3) kernfs needs to be fixed.  The rest of the dropped commits were
made redundant by 8e04944f0ea8; this one wasn't.  Mea culpa.