From: Aleksa Sarai <cyphar@cyphar.com>
To: "Mickaël Salaün" <mic@digikod.net>
Cc: linux-kernel@vger.kernel.org,
"Alexei Starovoitov" <ast@kernel.org>,
"Al Viro" <viro@zeniv.linux.org.uk>,
"Andy Lutomirski" <luto@kernel.org>,
"Christian Heimes" <christian@python.org>,
"Daniel Borkmann" <daniel@iogearbox.net>,
"Deven Bowers" <deven.desai@linux.microsoft.com>,
"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>,
"Kees Cook" <keescook@chromium.org>,
"Matthew Garrett" <mjg59@google.com>,
"Matthew Wilcox" <willy@infradead.org>,
"Michael Kerrisk" <mtk.manpages@gmail.com>,
"Mickaël Salaün" <mickael.salaun@ssi.gouv.fr>,
"Mimi Zohar" <zohar@linux.ibm.com>,
"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>,
kernel-hardening@lists.openwall.com, linux-api@vger.kernel.org,
linux-security-module@vger.kernel.org,
linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH v3 0/5] Add support for RESOLVE_MAYEXEC
Date: Thu, 30 Apr 2020 11:54:29 +1000 [thread overview]
Message-ID: <20200430015429.wuob7m5ofdewubui@yavin.dot.cyphar.com> (raw)
In-Reply-To: <20200428175129.634352-1-mic@digikod.net>
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On 2020-04-28, Mickaël Salaün <mic@digikod.net> wrote:
> The goal of this patch series is to enable to control script execution
> with interpreters help. A new RESOLVE_MAYEXEC flag, usable through
> openat2(2), is added to enable userspace script interpreter to delegate
> to the kernel (and thus the system security policy) the permission to
> interpret/execute scripts or other files containing what can be seen as
> commands.
>
> This third patch series mainly differ from the previous one by relying
> on the new openat2(2) system call to get rid of the undefined behavior
> of the open(2) flags. Thus, the previous O_MAYEXEC flag is now replaced
> with the new RESOLVE_MAYEXEC flag and benefits from the openat2(2)
> strict check of this kind of flags.
My only strong upfront objection is with this being a RESOLVE_ flag.
RESOLVE_ flags have a specific meaning (they generally apply to all
components, and affect the rules of path resolution). RESOLVE_MAYEXEC
does neither of these things and so seems out of place among the other
RESOLVE_ flags.
I would argue this should be an O_ flag, but not supported for the
old-style open(2). This is what the O_SPECIFIC_FD patchset does[1] and I
think it's a reasonable way of solving such problems.
--
Aleksa Sarai
Senior Software Engineer (Containers)
SUSE Linux GmbH
<https://www.cyphar.com/>
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next prev parent reply other threads:[~2020-04-30 1:54 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-28 17:51 [PATCH v3 0/5] Add support for RESOLVE_MAYEXEC Mickaël Salaün
2020-04-28 17:51 ` [PATCH v3 1/5] fs: Add support for a RESOLVE_MAYEXEC flag on openat2(2) Mickaël Salaün
2020-05-01 4:04 ` James Morris
2020-05-01 14:14 ` Mickaël Salaün
2020-04-28 17:51 ` [PATCH v3 2/5] fs: Add a MAY_EXECMOUNT flag to infer the noexec mount property Mickaël Salaün
2020-05-01 4:02 ` James Morris
2020-05-01 14:17 ` Mickaël Salaün
2020-04-28 17:51 ` [PATCH v3 3/5] fs: Enable to enforce noexec mounts or file exec through RESOLVE_MAYEXEC Mickaël Salaün
2020-05-01 4:22 ` James Morris
2020-05-01 14:32 ` Mickaël Salaün
2020-05-01 18:05 ` James Morris
2020-04-28 17:51 ` [PATCH v3 4/5] selftest/openat2: Add tests for RESOLVE_MAYEXEC enforcing Mickaël Salaün
2020-04-28 17:51 ` [PATCH v3 5/5] doc: Add documentation for the fs.open_mayexec_enforce sysctl Mickaël Salaün
2020-04-28 19:21 ` [PATCH v3 0/5] Add support for RESOLVE_MAYEXEC Jann Horn
2020-04-28 21:20 ` Florian Weimer
2020-04-28 22:01 ` Jann Horn
2020-04-29 8:50 ` Mickaël Salaün
2020-05-01 11:47 ` Christian Heimes
2020-05-05 14:57 ` Mickaël Salaün
2020-04-30 1:54 ` Aleksa Sarai [this message]
2020-04-30 8:07 ` Christian Brauner
2020-04-30 10:45 ` Mickaël Salaün
2020-05-01 3:53 ` James Morris
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