linux-kernel - Re: [RFC] fs: add userspace critical mounts event support

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

Message-ID: <CAB=NE6UXX+=nnJcOgO7NWudmDR3bESVO-mQrqG26Gpd4z71xqA@mail.gmail.com>
Date:   Tue, 4 Oct 2016 17:24:14 -0700
From:   "Luis R. Rodriguez" <mcgrof@...nel.org>
To:     Linus Torvalds <torvalds@...ux-foundation.org>
Cc:     Dmitry Torokhov <dmitry.torokhov@...il.com>,
        "Herbert, Marc" <marc.herbert@...el.com>,
        "open list:DOCUMENTATION" <linux-doc@...r.kernel.org>,
        Jacek Anaszewski <j.anaszewski@...sung.com>,
        David Woodhouse <dwmw2@...radead.org>,
        Christian Lamparter <chunkeey@...glemail.com>,
        Julia Lawall <Julia.Lawall@...6.fr>,
        Andrew Morton <akpm@...ux-foundation.org>,
        linuxppc-dev <linuxppc-dev@...ts.ozlabs.org>,
        Mimi Zohar <zohar@...ux.vnet.ibm.com>,
        Andy Lutomirski <luto@...capital.net>,
        Richard Purdie <rpurdie@...ys.net>,
        Wu Fengguang <fengguang.wu@...el.com>,
        Johannes Berg <johannes@...solutions.net>,
        Michal Marek <mmarek@...e.com>,
        Hauke Mehrtens <hauke@...ke-m.de>,
        Mark Brown <broonie@...nel.org>, Jiri Slaby <jslaby@...e.com>,
        Ming Lei <ming.lei@...onical.com>,
        Daniel Vetter <daniel.vetter@...ll.ch>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Felix Fietkau <nbd@....name>, Roman Pen <r.peniaev@...il.com>,
        Greg KH <gregkh@...uxfoundation.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Vikram Mulukutla <markivx@...eaurora.org>,
        Stephen Boyd <stephen.boyd@...aro.org>,
        Takashi Iwai <tiwai@...e.de>, Jeff Mahoney <jeffm@...e.com>,
        Hariprasad S <hariprasad@...lsio.com>,
        Benjamin Poirier <bpoirier@...e.de>,
        Josh Triplett <josh@...htriplett.org>
Subject: Re: [RFC] fs: add userspace critical mounts event support

On Tue, Oct 4, 2016 at 5:12 PM, Linus Torvalds
<torvalds@...ux-foundation.org> wrote:
> On Tue, Oct 4, 2016 at 5:00 PM, Luis R. Rodriguez <mcgrof@...nel.org> wrote:
>>
>> I am not sure how/why a firmware loading daemon would be a better
>> idea now. What Marc describes that Josh proposed with signals for
>> userspcae seems more aligned with what we likely need
>
> Quite frankly, I doubt you want a signal.
>
> You will want to have some way to specify where the firmware files
> are. Right now we have "fw_path[]" which is hardcoded except for the
> first entry that can be set as a module parameter. But you'd probably
> want to expand on that, which implies some /sys or /proc interface.
>
> And once you do that, wouldn't it make more sense to just make the
> "update the firmware path /proc/sys/kernel/fw_path file" make things
> re-search for firmware?

We can, but re-searching for firmware assumes we cache pending
firmware, we currently don't, we just either process sync or async
firmware requests.

> In other words, the interface has to be something *sensible*. Not some
> idiotic ad-hoc "send a signal" (of which that stupid original patch
> was just a very odd example).

Note that the races are beyond firmware, so all
kernel_read_file_from_path() users, as such re-using such old /sys/
interafeces for firmware will not suffice to cover all ground now for
the same race for other possible users.

 Luis