[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20240709.eud4ao8Kie6n@digikod.net>
Date: Tue, 9 Jul 2024 22:41:54 +0200
From: Mickaël Salaün <mic@...ikod.net>
To: Jeff Xu <jeffxu@...gle.com>
Cc: Florian Weimer <fweimer@...hat.com>, Al Viro <viro@...iv.linux.org.uk>,
Christian Brauner <brauner@...nel.org>, Kees Cook <keescook@...omium.org>,
Linus Torvalds <torvalds@...ux-foundation.org>, Paul Moore <paul@...l-moore.com>, Theodore Ts'o <tytso@....edu>,
Alejandro Colomar <alx@...nel.org>, Aleksa Sarai <cyphar@...har.com>,
Andrew Morton <akpm@...ux-foundation.org>, Andy Lutomirski <luto@...nel.org>, Arnd Bergmann <arnd@...db.de>,
Casey Schaufler <casey@...aufler-ca.com>, Christian Heimes <christian@...hon.org>,
Dmitry Vyukov <dvyukov@...gle.com>, Eric Biggers <ebiggers@...nel.org>,
Eric Chiang <ericchiang@...gle.com>, Fan Wu <wufan@...ux.microsoft.com>,
Geert Uytterhoeven <geert@...ux-m68k.org>, James Morris <jamorris@...ux.microsoft.com>,
Jan Kara <jack@...e.cz>, Jann Horn <jannh@...gle.com>, Jonathan Corbet <corbet@....net>,
Jordan R Abrahams <ajordanr@...gle.com>, Lakshmi Ramasubramanian <nramas@...ux.microsoft.com>,
Luca Boccassi <bluca@...ian.org>, Luis Chamberlain <mcgrof@...nel.org>,
"Madhavan T . Venkataraman" <madvenka@...ux.microsoft.com>, Matt Bobrowski <mattbobrowski@...gle.com>,
Matthew Garrett <mjg59@...f.ucam.org>, Matthew Wilcox <willy@...radead.org>,
Miklos Szeredi <mszeredi@...hat.com>, Mimi Zohar <zohar@...ux.ibm.com>,
Nicolas Bouchinet <nicolas.bouchinet@....gouv.fr>, Scott Shell <scottsh@...rosoft.com>,
Shuah Khan <shuah@...nel.org>, Stephen Rothwell <sfr@...b.auug.org.au>,
Steve Dower <steve.dower@...hon.org>, Steve Grubb <sgrubb@...hat.com>,
Thibaut Sautereau <thibaut.sautereau@....gouv.fr>, Vincent Strubel <vincent.strubel@....gouv.fr>,
Xiaoming Ni <nixiaoming@...wei.com>, Yin Fengwei <fengwei.yin@...el.com>,
kernel-hardening@...ts.openwall.com, linux-api@...r.kernel.org, linux-fsdevel@...r.kernel.org,
linux-integrity@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-security-module@...r.kernel.org
Subject: Re: [RFC PATCH v19 1/5] exec: Add a new AT_CHECK flag to execveat(2)
On Tue, Jul 09, 2024 at 11:57:27AM -0700, Jeff Xu wrote:
> On Tue, Jul 9, 2024 at 2:18 AM Mickaël Salaün <mic@...ikod.net> wrote:
> >
> > On Mon, Jul 08, 2024 at 10:52:36AM -0700, Jeff Xu wrote:
> > > On Mon, Jul 8, 2024 at 10:33 AM Florian Weimer <fweimer@...hat.com> wrote:
> > > >
> > > > * Jeff Xu:
> > > >
> > > > > On Mon, Jul 8, 2024 at 9:26 AM Florian Weimer <fweimer@...hat.com> wrote:
> > > > >>
> > > > >> * Jeff Xu:
> > > > >>
> > > > >> > Will dynamic linkers use the execveat(AT_CHECK) to check shared
> > > > >> > libraries too ? or just the main executable itself.
> > > > >>
> > > > >> I expect that dynamic linkers will have to do this for everything they
> > > > >> map.
> > > > > Then all the objects (.so, .sh, etc.) will go through the check from
> > > > > execveat's main to security_bprm_creds_for_exec(), some of them might
> > > > > be specific for the main executable ?
> >
> > Yes, we should check every executable code (including seccomp filters)
> > to get a consistent policy.
> >
> > What do you mean by "specific for the main executable"?
> >
> I meant:
>
> The check is for the exe itself, not .so, etc.
>
> For example: /usr/bin/touch is checked.
> not the shared objects:
> ldd /usr/bin/touch
> linux-vdso.so.1 (0x00007ffdc988f000)
> libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f59b6757000)
> /lib64/ld-linux-x86-64.so.2 (0x00007f59b6986000)
ld.so should be patched to check shared-objects.
>
> Basically, I asked if the check can be extended to shared-objects,
> seccomp filters, etc, without modifying existing LSMs.
Yes, the check should be used against any piece of code such as
shared-objects, seccomp filters...
> you pointed out "LSM should not need to be updated with this patch
> series.", which already answered my question.
>
> Thanks.
> -Jeff
>
> -Jeff
Powered by blists - more mailing lists
Confused about mailing lists and their use?
Read about mailing lists on Wikipedia
and check out these
guidelines on proper formatting of your messages.
