From: Kees Cook <keescook@chromium.org>
To: "Mickaël Salaün" <mic@digikod.net>
Cc: "Al Viro" <viro@zeniv.linux.org.uk>,
"Aleksa Sarai" <cyphar@cyphar.com>,
"Andy Lutomirski" <luto@kernel.org>,
"Mimi Zohar" <zohar@linux.ibm.com>,
"Stephen Smalley" <stephen.smalley.work@gmail.com>,
"Christian Heimes" <christian@python.org>,
"Deven Bowers" <deven.desai@linux.microsoft.com>,
"Tetsuo Handa" <penguin-kernel@I-love.SAKURA.ne.jp>,
"John Johansen" <john.johansen@canonical.com>,
"Kentaro Takeda" <takedakn@nttdata.co.jp>,
"Lev R. Oshvang ." <levonshe@gmail.com>,
"Alexei Starovoitov" <ast@kernel.org>,
"Daniel Borkmann" <daniel@iogearbox.net>,
"Eric Chiang" <ericchiang@google.com>,
"Florian Weimer" <fweimer@redhat.com>,
"James Morris" <jmorris@namei.org>, "Jan Kara" <jack@suse.cz>,
"Jann Horn" <jannh@google.com>,
"Jonathan Corbet" <corbet@lwn.net>,
"Lakshmi Ramasubramanian" <nramas@linux.microsoft.com>,
"Matthew Garrett" <mjg59@google.com>,
"Matthew Wilcox" <willy@infradead.org>,
"Michael Kerrisk" <mtk.manpages@gmail.com>,
"Mickaël Salaün" <mickael.salaun@ssi.gouv.fr>,
"Philippe Trébuchet" <philippe.trebuchet@ssi.gouv.fr>,
"Scott Shell" <scottsh@microsoft.com>,
"Sean Christopherson" <sean.j.christopherson@intel.com>,
"Shuah Khan" <shuah@kernel.org>,
"Steve Dower" <steve.dower@python.org>,
"Steve Grubb" <sgrubb@redhat.com>,
"Thibaut Sautereau" <thibaut.sautereau@ssi.gouv.fr>,
"Vincent Strubel" <vincent.strubel@ssi.gouv.fr>,
linux-kernel <linux-kernel@vger.kernel.org>,
kernel-hardening@lists.openwall.com, linux-api@vger.kernel.org,
linux-integrity@vger.kernel.org,
"LSM List" <linux-security-module@vger.kernel.org>,
"Linux FS Devel" <linux-fsdevel@vger.kernel.org>
Subject: How about just O_EXEC? (was Re: [PATCH v5 3/6] fs: Enable to enforce noexec mounts or file exec through O_MAYEXEC)
Date: Fri, 15 May 2020 01:01:32 -0700 [thread overview]
Message-ID: <202005142343.D580850@keescook> (raw)
In-Reply-To: <b740d658-a2da-5773-7a10-59a0ca52ac6b@digikod.net>
On Thu, May 14, 2020 at 09:16:13PM +0200, Mickaël Salaün wrote:
> On 14/05/2020 18:10, Stephen Smalley wrote:
> > On Thu, May 14, 2020 at 11:45 AM Kees Cook <keescook@chromium.org> wrote:
> >> So, it looks like adding FMODE_EXEC into f_flags in do_open() is needed in
> >> addition to injecting MAY_EXEC into acc_mode in do_open()? Hmmm
> >
> > Just do both in build_open_flags() and be done with it? Looks like he
> > was already setting FMODE_EXEC in patch 1 so we just need to teach
> > AppArmor/TOMOYO to check for it and perform file execute checking in
> > that case if !current->in_execve?
>
> I can postpone the file permission check for another series to make this
> one simpler (i.e. mount noexec only). Because it depends on the sysctl
> setting, it is OK to add this check later, if needed. In the meantime,
> AppArmor and Tomoyo could be getting ready for this.
So, after playing around with this series, investigating Stephen's
comments, digging through the existing FMODE_EXEC uses, and spending a
bit more time thinking about Lev and Aleksa's dislike of the sysctls, I've
got a much more radically simplified solution that I think could work.
Maybe I've missed some earlier discussion that ruled this out, but I
couldn't find it: let's just add O_EXEC and be done with it. It actually
makes the execve() path more like openat2() and is much cleaner after
a little refactoring. Here are the results, though I haven't emailed it
yet since I still want to do some more testing:
https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git/log/?h=kspp/o_exec/v1
I look forward to flames! ;)
--
Kees Cook
next prev parent reply other threads:[~2020-05-15 8:01 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-05 15:31 [PATCH v5 0/6] Add support for O_MAYEXEC Mickaël Salaün
2020-05-05 15:31 ` [PATCH v5 1/6] fs: Add support for an O_MAYEXEC flag on openat2(2) Mickaël Salaün
2020-05-12 21:05 ` Kees Cook
2020-05-12 21:40 ` Christian Heimes
2020-05-12 22:56 ` Kees Cook
2020-05-13 10:13 ` Mickaël Salaün
2020-05-05 15:31 ` [PATCH v5 2/6] fs: Add a MAY_EXECMOUNT flag to infer the noexec mount property Mickaël Salaün
2020-05-12 21:09 ` Kees Cook
2020-05-14 8:14 ` Lev R. Oshvang .
2020-05-14 15:48 ` Kees Cook
2020-05-17 16:57 ` Lev R. Oshvang .
2020-05-05 15:31 ` [PATCH v5 3/6] fs: Enable to enforce noexec mounts or file exec through O_MAYEXEC Mickaël Salaün
2020-05-05 15:44 ` Randy Dunlap
2020-05-05 16:55 ` Mickaël Salaün
2020-05-05 17:40 ` Randy Dunlap
2020-05-12 21:48 ` Kees Cook
2020-05-13 11:09 ` Mickaël Salaün
2020-05-13 15:37 ` Stephen Smalley
2020-05-13 23:27 ` Kees Cook
2020-05-14 3:05 ` Kees Cook
2020-05-14 10:12 ` David Laight
2020-05-14 12:22 ` Stephen Smalley
2020-05-14 14:41 ` Kees Cook
2020-05-14 15:52 ` Stephen Smalley
2020-05-14 15:45 ` Kees Cook
2020-05-14 16:10 ` Stephen Smalley
2020-05-14 19:16 ` Mickaël Salaün
2020-05-15 0:58 ` Tetsuo Handa
2020-05-15 8:01 ` Kees Cook [this message]
2020-05-15 8:43 ` How about just O_EXEC? (was Re: [PATCH v5 3/6] fs: Enable to enforce noexec mounts or file exec through O_MAYEXEC) Florian Weimer
2020-05-15 14:37 ` Kees Cook
2020-05-15 14:43 ` Florian Weimer
2020-05-15 15:50 ` Kees Cook
2020-05-18 7:26 ` Florian Weimer
2020-05-19 2:23 ` Aleksa Sarai
2020-05-19 10:13 ` Mickaël Salaün
2020-05-15 11:04 ` Mickaël Salaün
2020-05-15 15:46 ` Kees Cook
2020-05-15 18:24 ` Mickaël Salaün
2020-05-14 19:21 ` [PATCH v5 3/6] fs: Enable to enforce noexec mounts or file exec through O_MAYEXEC Mickaël Salaün
2020-05-05 15:31 ` [PATCH v5 4/6] selftest/openat2: Add tests for O_MAYEXEC enforcing Mickaël Salaün
2020-05-12 21:57 ` Kees Cook
2020-05-13 11:18 ` Mickaël Salaün
2020-05-05 15:31 ` [PATCH v5 5/6] doc: Add documentation for the fs.open_mayexec_enforce sysctl Mickaël Salaün
2020-05-12 22:00 ` Kees Cook
2020-05-13 11:20 ` Mickaël Salaün
2020-05-05 15:31 ` [PATCH v5 6/6] ima: add policy support for the new file open MAY_OPENEXEC flag Mickaël Salaün
2020-05-05 15:36 ` [PATCH v5 0/6] Add support for O_MAYEXEC Mickaël Salaün
2020-05-06 13:58 ` Lev R. Oshvang .
2020-05-06 15:41 ` Aleksa Sarai
2020-05-07 8:30 ` Mickaël Salaün
2020-05-07 8:05 ` David Laight
2020-05-07 8:36 ` Mickaël Salaün
2020-05-07 9:00 ` David Laight
2020-05-07 9:30 ` Mickaël Salaün
2020-05-07 9:44 ` David Laight
2020-05-07 13:38 ` Mickaël Salaün
2020-05-08 7:15 ` Lev R. Oshvang .
2020-05-08 14:01 ` Mimi Zohar
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