From: Oleg Nesterov <oleg@redhat.com>
To: Tycho Andersen <tycho@tycho.ws>
Cc: Kees Cook <keescook@chromium.org>, linux-kernel@vger.kernel.org
Subject: Re: null dereference in binfmt misc
Date: Tue, 10 Oct 2017 14:04:02 +0200 [thread overview]
Message-ID: <20171010120402.GA32446@redhat.com> (raw)
In-Reply-To: <20171010111647.GA27310@redhat.com>
On 10/10, Oleg Nesterov wrote:
>
> On 10/09, Tycho Andersen wrote:
> > Hi,
> >
> > It looks like eb23aa031 ("exec: binfmt_misc: remove the confusing
> > e->interp_file != NULL checks") uncovered a bug for me (see the trace below,
> > which I'm afraid isn't very helpful).
>
> Well, I think this commit uncovered the fact I am stupid, although there is
> nothing new. I forgot about iput() in bm_register_write's error paths, it can
> be called with MISC_FMT_OPEN_FILE && interp_file == NULL.
>
> I'll try to cleanup bm_register_write() to make this impossible, or perhaps
> I will just restore the interp_file != NULL check in evict.
Yes, but...
> Before that, could you please try the debugging patch below? To ensure you
> didn't hit another problem.
please ignore. scripts/decodecode suggests you hit another problem,
inode->i_private is NULL.
I'll send the patch today, thanks.
Oleg.
prev parent reply other threads:[~2017-10-10 12:04 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-09 21:19 null dereference in binfmt misc Tycho Andersen
2017-10-10 6:49 ` Santosh Sivaraj
2017-10-10 11:16 ` Oleg Nesterov
2017-10-10 12:04 ` Oleg Nesterov [this message]
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