linux-kernel - RE: [PATCH v7 0/7] Add support for O

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]

Date:   Tue, 11 Aug 2020 08:09:10 +0000
From:   David Laight <David.Laight@...LAB.COM>
To:     'Mickaël Salaün' <mic@...ikod.net>,
        Al Viro <viro@...iv.linux.org.uk>
CC:     Kees Cook <keescook@...omium.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Aleksa Sarai <cyphar@...har.com>,
        "Alexei Starovoitov" <ast@...nel.org>,
        Andy Lutomirski <luto@...nel.org>,
        "Christian Brauner" <christian.brauner@...ntu.com>,
        Christian Heimes <christian@...hon.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Deven Bowers <deven.desai@...ux.microsoft.com>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        "Eric Biggers" <ebiggers@...nel.org>,
        Eric Chiang <ericchiang@...gle.com>,
        "Florian Weimer" <fweimer@...hat.com>,
        James Morris <jmorris@...ei.org>, Jan Kara <jack@...e.cz>,
        Jann Horn <jannh@...gle.com>, Jonathan Corbet <corbet@....net>,
        Lakshmi Ramasubramanian <nramas@...ux.microsoft.com>,
        Matthew Garrett <mjg59@...gle.com>,
        Matthew Wilcox <willy@...radead.org>,
        Michael Kerrisk <mtk.manpages@...il.com>,
        Mimi Zohar <zohar@...ux.ibm.com>,
        Philippe Trébuchet 
        <philippe.trebuchet@....gouv.fr>,
        "Scott Shell" <scottsh@...rosoft.com>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Shuah Khan <shuah@...nel.org>,
        Steve Dower <steve.dower@...hon.org>,
        Steve Grubb <sgrubb@...hat.com>,
        Tetsuo Handa <penguin-kernel@...ove.sakura.ne.jp>,
        Thibaut Sautereau <thibaut.sautereau@...p-os.org>,
        Vincent Strubel <vincent.strubel@....gouv.fr>,
        "kernel-hardening@...ts.openwall.com" 
        <kernel-hardening@...ts.openwall.com>,
        "linux-api@...r.kernel.org" <linux-api@...r.kernel.org>,
        "linux-integrity@...r.kernel.org" <linux-integrity@...r.kernel.org>,
        "linux-security-module@...r.kernel.org" 
        <linux-security-module@...r.kernel.org>,
        "linux-fsdevel@...r.kernel.org" <linux-fsdevel@...r.kernel.org>
Subject: RE: [PATCH v7 0/7] Add support for O_MAYEXEC

> On 11/08/2020 00:28, Al Viro wrote:
> > On Mon, Aug 10, 2020 at 10:09:09PM +0000, David Laight wrote:
> >>> On Mon, Aug 10, 2020 at 10:11:53PM +0200, Mickaël Salaün wrote:
> >>>> It seems that there is no more complains nor questions. Do you want me
> >>>> to send another series to fix the order of the S-o-b in patch 7?
> >>>
> >>> There is a major question regarding the API design and the choice of
> >>> hooking that stuff on open().  And I have not heard anything resembling
> >>> a coherent answer.
> >>
> >> To me O_MAYEXEC is just the wrong name.
> >> The bit would be (something like) O_INTERPRET to indicate
> >> what you want to do with the contents.
> 
> The properties is "execute permission". This can then be checked by
> interpreters or other applications, then the generic O_MAYEXEC name.

The english sense of MAYEXEC is just wrong for what you are trying
to check.

> > ... which does not answer the question - name of constant is the least of
> > the worries here.  Why the hell is "apply some unspecified checks to
> > file" combined with opening it, rather than being an independent primitive
> > you apply to an already opened file?  Just in case - "'cuz that's how we'd
> > done it" does not make a good answer...

Maybe an access_ok() that acts on an open fd would be more
appropriate.
Which might end up being an fcntrl() action.
That would give you a full 32bit mask of options.

	David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)