From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from second.openwall.net (second.openwall.net [193.110.157.125]) by smtp.lore.kernel.org (Postfix) with SMTP id 3210AC2BD09 for ; Tue, 9 Jul 2024 20:42:32 +0000 (UTC) Received: (qmail 27701 invoked by uid 550); 9 Jul 2024 20:42:18 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Received: (qmail 27680 invoked from network); 9 Jul 2024 20:42:18 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=digikod.net; s=20191114; t=1720557730; bh=b/6BV4qENhC2jLKcP5I5zsdG+AAW0O4kWpLE4Pdgsx4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=lcV5oubD1HhBRpEpPcxMKtGDQ9TqcBhGdXp79aW87IvdgoYtwICUbJiuLCQusIsIV zh8XujpWxWy+Q6jb/cLpy5yf5/lNSPPTQTakgJ4Fnp3uiHbRPiZzsRSnz0PcG6yhmS Xf0ItQwcE5vjbwKGxHDcSNrW5WjR6671nkei7WCU= Date: Tue, 9 Jul 2024 22:41:54 +0200 From: =?utf-8?Q?Micka=C3=ABl_Sala=C3=BCn?= To: Jeff Xu Cc: Florian Weimer , Al Viro , Christian Brauner , Kees Cook , Linus Torvalds , Paul Moore , Theodore Ts'o , Alejandro Colomar , Aleksa Sarai , Andrew Morton , Andy Lutomirski , Arnd Bergmann , Casey Schaufler , Christian Heimes , Dmitry Vyukov , Eric Biggers , Eric Chiang , Fan Wu , Geert Uytterhoeven , James Morris , Jan Kara , Jann Horn , Jonathan Corbet , Jordan R Abrahams , Lakshmi Ramasubramanian , Luca Boccassi , Luis Chamberlain , "Madhavan T . Venkataraman" , Matt Bobrowski , Matthew Garrett , Matthew Wilcox , Miklos Szeredi , Mimi Zohar , Nicolas Bouchinet , Scott Shell , Shuah Khan , Stephen Rothwell , Steve Dower , Steve Grubb , Thibaut Sautereau , Vincent Strubel , Xiaoming Ni , Yin Fengwei , kernel-hardening@lists.openwall.com, linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org Subject: Re: [RFC PATCH v19 1/5] exec: Add a new AT_CHECK flag to execveat(2) Message-ID: <20240709.eud4ao8Kie6n@digikod.net> References: <20240704190137.696169-1-mic@digikod.net> <20240704190137.696169-2-mic@digikod.net> <87bk3bvhr1.fsf@oldenburg.str.redhat.com> <87ed83etpk.fsf@oldenburg.str.redhat.com> <87r0c3dc1c.fsf@oldenburg.str.redhat.com> <20240709.gae4cu4Aiv6s@digikod.net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Infomaniak-Routing: alpha On Tue, Jul 09, 2024 at 11:57:27AM -0700, Jeff Xu wrote: > On Tue, Jul 9, 2024 at 2:18 AM Mickaël Salaün 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 wrote: > > > > > > > > * Jeff Xu: > > > > > > > > > On Mon, Jul 8, 2024 at 9:26 AM Florian Weimer 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