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 X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 42C17C433E2 for ; Wed, 24 Jun 2020 15:41:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1B81120706 for ; Wed, 24 Jun 2020 15:41:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=yahoo.com header.i=@yahoo.com header.b="mCr/+nVW" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404224AbgFXPln (ORCPT ); Wed, 24 Jun 2020 11:41:43 -0400 Received: from sonic310-30.consmr.mail.ne1.yahoo.com ([66.163.186.211]:36387 "EHLO sonic310-30.consmr.mail.ne1.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2404235AbgFXPlm (ORCPT ); Wed, 24 Jun 2020 11:41:42 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=s2048; t=1593013300; bh=Dhys375vlyZYm8Ra4CA3t0cqtfMxqok7JpN+dbu2zhQ=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From:Subject; b=mCr/+nVWuFV8upxA/hRon6D8FlUc1EILZG+cbv3qkSg5rTjXgg6WkirhUGxAwv3jKXa2a2yYeokjPfcMcbYpLfvvCZX31237cYQnt8wfGQoFs2bM5K1aVmrdst/k78I32y90UWkpJYFVvMbsAGXA7OLqWG6vz8jJZJOX76Ap8/u4JUSluEboSuMbGosHKWXz+swXTac5Q6pUEkkT6nGnDXAAjyhNfSWmISANFDP6MuLB3GZpSvViymlm+bBfc1WScsCE6l77rqqLDBfyqZVyec1glqEchYSrdmS5yp5Tgl2Z5JfKNUpHI5XvYbBWsLJpibN3rqCk6o16947HJVOK6g== X-YMail-OSG: 3.43OegVM1nvctIiVOWVEtfptGPuuw8gMmJge0iKY41Zh_yO8EMoafQ7KyORN_Z rOx0rU2XIgJti6OZ.qTUAT8.TKvltAYwleaVQ2aPSIhnMWDY44OB7f3fR1eupqLFXNJHHaNCtNBD c7qiZ6w8y0YFIpdGMvKj7sKJn6mFRD9_9rMlngvGozrZjb7xVnuKg0f._3qxio1.V0.mK7tvp71e kB2s.6ALQyu1XlHZDTRjX5_azmFf8VnnEKuwnkOMmfSkwQOqLdYdrHAkqDPvI1aqbrHSxaaoVCgq iICphgi9CyrLk34lT6lvgjz4q7dzxzJzr4igMutKbrr6EgMOR8PQDKGrdjRll0eXH9Z5L.aGwK7R exqHPV478mg8BusqNmVJl8QmrC_qXXux3GNTEsFFFkVQCxoKEB9b2TWmPWAfTqXo7cVt6r0Mq85U Ue6KJiwBw9Z6tUdSQIADUS8wlbCdfLXAjI1qMnmnnpvIcxA7qqvhHPIAQPx.oVXJ9qdrpcI3Rrnv ERKtRdgLdP589ML3lvCiwjpXp6gaWIgPSAiG9WhxSamj9irPMU7zTErp_vq5yQ44LIuuITB06sql Dmgt4HlyyRRilySv5ki0zHTVJ9mQwnUFL4rMZQW9_9baWGspqR7yQreBKF5DYvhcSzZeJObRP_EI MFnINsG1avcU7jgEDN6czR64jbwuRgCdZ_7zYN869yBnyKTyYGUiJK4.onxNN3jBJCzFQN6Fw2jX x3xWSc8LBBiAB2VK_llYlFyip4rvr0O2ihH_qCzsiUSj8trupAmjbl1ZDC00TQz8ee2V_yOFuMFX GwyRC5thDQ91hEW3z1HSZaCqEbPHko3kQzvQsSwqaF6wXYI6zlUyZPZpc_0apTFjIByV9KkHCeiI t.dRB0ZU4KPIJVjY9DXjjwUAJUlLSGlWjQtF3ZThb43z07iGR7HBH_o.mpaDNuaytUqHUHpemvFc VTYGV2rDphZlQU7U5k5Ue.12QXsVFYLFx7jHCRFgQMJyl2IAdU8h5f5mlfwqyxIglUQvXk50PMs9 xmiEfQ.6rKFKYsbRSqW1tyQJFn7sEFbNeSAlGcdtP_qj.E0YNH3BWRlcMxlpS51Elc2gphIatkaH CXEMqt8OA6tKmQIe3j_s3gY0K8y7EAXH2DhthI4iheW2bHsbK_Pg3OrH6H2Lf7MLfmGj1MQk78V2 DNxFuobeDADCcpSVzmGMt6mdsRzeQDIN27lab.APxzofNErXShk4mOSH.T3S9XYZDr6t.3IiCajA 0tewg496QDESFcLnT1ZSV9jnsAvw9gGqtP9MmIQTPsX0cXo20FAqNuZU4rvJysYsNfP6tsGvffRr dQc6AqnHTSeLfVSFQgGpddAxVhR.6jWRTlWxOdcGlOOZxsyHpBEVEWLgZ96IfoGpXizA4ucfHGyz 0s8r4VPfMnrbt.Tlhyorp9dFY.fUOuSM- Received: from sonic.gate.mail.ne1.yahoo.com by sonic310.consmr.mail.ne1.yahoo.com with HTTP; Wed, 24 Jun 2020 15:41:40 +0000 Received: by smtp421.mail.ne1.yahoo.com (VZM Hermes SMTP Server) with ESMTPA ID 99d8225b956cba644f47d6b97428fa53; Wed, 24 Jun 2020 15:41:39 +0000 (UTC) Subject: Re: [RFC][PATCH] net/bpfilter: Remove this broken and apparently unmantained To: Tetsuo Handa , linux-security-module Cc: Alexei Starovoitov , "Eric W. Biederman" , Linus Torvalds , Kees Cook , Andrew Morton , Alexei Starovoitov , David Miller , Al Viro , bpf , linux-fsdevel , Daniel Borkmann , Jakub Kicinski , Masahiro Yamada , Gary Lin , Bruno Meneguele , Casey Schaufler References: <87ftaxd7ky.fsf@x220.int.ebiederm.org> <20200616015552.isi6j5x732okiky4@ast-mbp.dhcp.thefacebook.com> <87h7v1pskt.fsf@x220.int.ebiederm.org> <20200623183520.5e7fmlt3omwa2lof@ast-mbp.dhcp.thefacebook.com> <87h7v1mx4z.fsf@x220.int.ebiederm.org> <20200623194023.lzl34qt2wndhcehk@ast-mbp.dhcp.thefacebook.com> <20200624040054.x5xzkuhiw67cywzl@ast-mbp.dhcp.thefacebook.com> <5254444e-465e-6dee-287b-bef58526b724@i-love.sakura.ne.jp> <20200624063940.ctzhf4nnh3cjyxqi@ast-mbp.dhcp.thefacebook.com> <321b85b4-95f0-2f9b-756a-8405adc97230@i-love.sakura.ne.jp> From: Casey Schaufler Autocrypt: addr=casey@schaufler-ca.com; keydata= mQINBFzV9HABEAC/mmv3jeJyF7lR7QhILYg1+PeBLIMZv7KCzBSc/4ZZipoWdmr77Lel/RxQ 1PrNx0UaM5r6Hj9lJmJ9eg4s/TUBSP67mTx+tsZ1RhG78/WFf9aBe8MSXxY5cu7IUwo0J/CG vdSqACKyYPV5eoTJmnMxalu8/oVUHyPnKF3eMGgE0mKOFBUMsb2pLS/enE4QyxhcZ26jeeS6 3BaqDl1aTXGowM5BHyn7s9LEU38x/y2ffdqBjd3au2YOlvZ+XUkzoclSVfSR29bomZVVyhMB h1jTmX4Ac9QjpwsxihT8KNGvOM5CeCjQyWcW/g8LfWTzOVF9lzbx6IfEZDDoDem4+ZiPsAXC SWKBKil3npdbgb8MARPes2DpuhVm8yfkJEQQmuLYv8GPiJbwHQVLZGQAPBZSAc7IidD2zbf9 XAw1/SJGe1poxOMfuSBsfKxv9ba2i8hUR+PH7gWwkMQaQ97B1yXYxVEkpG8Y4MfE5Vd3bjJU kvQ/tOBUCw5zwyIRC9+7zr1zYi/3hk+OG8OryZ5kpILBNCo+aePeAJ44znrySarUqS69tuXd a3lMPHUJJpUpIwSKQ5UuYYkWlWwENEWSefpakFAIwY4YIBkzoJ/t+XJHE1HTaJnRk6SWpeDf CreF3+LouP4njyeLEjVIMzaEpwROsw++BX5i5vTXJB+4UApTAQARAQABtChDYXNleSBTY2hh dWZsZXIgPGNhc2V5QHNjaGF1Zmxlci1jYS5jb20+iQJUBBMBCAA+FiEEC+9tH1YyUwIQzUIe OKUVfIxDyBEFAlzV9HACGwMFCRLMAwAFCwkIBwIGFQoJCAsCBBYCAwECHgECF4AACgkQOKUV fIxDyBG6ag/6AiRl8yof47YOEVHlrmewbpnlBTaYNfJ5cZflNRKRX6t4bp1B2YV1whlDTpiL vNOwFkh+ZE0eI5M4x8Gw2Oiok+4Q5liA9PHTozQYF+Ia+qdL5EehfbLGoEBqklpGvG3h8JsO 7SvONJuFDgvab/U/UriDYycJwzwKZuhVtK9EMpnTtUDyP3DY+Q8h7MWsniNBLVXnh4yBIEJg SSgDn3COpZoFTPGKE+rIzioo/GJe8CTa2g+ZggJiY/myWTS3quG0FMvwvNYvZ4I2g6uxSl7n bZVqAZgqwoTAv1HSXIAn9muwZUJL03qo25PFi2gQmX15BgJKQcV5RL0GHFHRThDS3IyadOgK P2j78P8SddTN73EmsG5OoyzwZAxXfck9A512BfVESqapHurRu2qvMoUkQaW/2yCeRQwGTsFj /rr0lnOBkyC6wCmPSKXe3dT2mnD5KnCkjn7KxLqexKt4itGjJz4/ynD/qh+gL7IPbifrQtVH JI7cr0fI6Tl8V6efurk5RjtELsAlSR6fKV7hClfeDEgLpigHXGyVOsynXLr59uE+g/+InVic jKueTq7LzFd0BiduXGO5HbGyRKw4MG5DNQvC//85EWmFUnDlD3WHz7Hicg95D+2IjD2ZVXJy x3LTfKWdC8bU8am1fi+d6tVEFAe/KbUfe+stXkgmfB7pxqW5Ag0EXNX0cAEQAPIEYtPebJzT wHpKLu1/j4jQcke06Kmu5RNuj1pEje7kX5IKzQSs+CPH0NbSNGvrA4dNGcuDUTNHgb5Be9hF zVqRCEvF2j7BFbrGe9jqMBWHuWheQM8RRoa2UMwQ704mRvKr4sNPh01nKT52ASbWpBPYG3/t WbYaqfgtRmCxBnqdOx5mBJIBh9Q38i63DjQgdNcsTx2qS7HFuFyNef5LCf3jogcbmZGxG/b7 yF4OwmGsVc8ufvlKo5A9Wm+tnRjLr/9Mn9vl5Xa/tQDoPxz26+aWz7j1in7UFzAarcvqzsdM Em6S7uT+qy5jcqyuipuenDKYF/yNOVSNnsiFyQTFqCPCpFihOnuaWqfmdeUOQHCSo8fD4aRF emsuxqcsq0Jp2ODq73DOTsdFxX2ESXYoFt3Oy7QmIxeEgiHBzdKU2bruIB5OVaZ4zWF+jusM Uh+jh+44w9DZkDNjxRAA5CxPlmBIn1OOYt1tsphrHg1cH1fDLK/pDjsJZkiH8EIjhckOtGSb aoUUMMJ85nVhN1EbU/A3DkWCVFEA//Vu1+BckbSbJKE7Hl6WdW19BXOZ7v3jo1q6lWwcFYth esJfk3ZPPJXuBokrFH8kqnEQ9W2QgrjDX3et2WwZFLOoOCItWxT0/1QO4ikcef/E7HXQf/ij Dxf9HG2o5hOlMIAkJq/uLNMvABEBAAGJAjwEGAEIACYWIQQL720fVjJTAhDNQh44pRV8jEPI EQUCXNX0cAIbDAUJEswDAAAKCRA4pRV8jEPIEWkzEACKFUnpp+wIVHpckMfBqN8BE5dUbWJc GyQ7wXWajLtlPdw1nNw0Wrv+ob2RCT7qQlUo6GRLcvj9Fn5tR4hBvR6D3m8aR0AGHbcC62cq I7LjaSDP5j/em4oVL2SMgNTrXgE2w33JMGjAx9oBzkxmKUqprhJomPwmfDHMJ0t7y39Da724 oLPTkQDpJL1kuraM9TC5NyLe1+MyIxqM/8NujoJbWeQUgGjn9uxQAil7o/xSCjrWCP3kZDID vd5ZaHpdl8e1mTExQoKr4EWgaMjmD/a3hZ/j3KfTVNpM2cLfD/QwTMaC2fkK8ExMsz+rUl1H icmcmpptCwOSgwSpPY1Zfio6HvEJp7gmDwMgozMfwQuT9oxyFTxn1X3rn1IoYQF3P8gsziY5 qtTxy2RrgqQFm/hr8gM78RhP54UPltIE96VywviFzDZehMvuwzW//fxysIoK97Y/KBZZOQs+ /T+Bw80Pwk/dqQ8UmIt2ffHEgwCTbkSm711BejapWCfklxkMZDp16mkxSt2qZovboVjXnfuq wQ1QL4o4t1hviM7LyoflsCLnQFJh6RSBhBpKQinMJl/z0A6NYDkQi6vEGMDBWX/M2vk9Jvwa v0cEBfY3Z5oFgkh7BUORsu1V+Hn0fR/Lqq/Pyq+nTR26WzGDkolLsDr3IH0TiAVH5ZuPxyz6 abzjfg== Message-ID: <748ef005-7f64-ab9b-c767-c617ec995df4@schaufler-ca.com> Date: Wed, 24 Jun 2020 08:41:37 -0700 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.9.0 MIME-Version: 1.0 In-Reply-To: <321b85b4-95f0-2f9b-756a-8405adc97230@i-love.sakura.ne.jp> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Content-Language: en-US X-Mailer: WebService/1.1.16138 hermes_yahoo Apache-HttpAsyncClient/4.1.4 (Java/11.0.7) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On 6/24/2020 12:05 AM, Tetsuo Handa wrote: > Forwarding to LSM-ML again. Any comments? Hey, BPF folks - you *really* need to do better about keeping the LSM community in the loop when you're discussing LSM issues.=20 > > On 2020/06/24 15:39, Alexei Starovoitov wrote: >> On Wed, Jun 24, 2020 at 01:58:33PM +0900, Tetsuo Handa wrote: >>> On 2020/06/24 13:00, Alexei Starovoitov wrote: >>>>> However, regarding usermode_blob, although the byte array (which co= ntains code / data) >>>>> might be initially loaded from the kernel space (which is protected= ), that byte array >>>>> is no longer protected (e.g. SIGKILL, strace()) when executed becau= se they are placed >>>>> in the user address space. Thus, LSM modules (including pathname ba= sed security) want >>>>> to control how that byte array can behave. >>>> It's privileged memory regardless. root can poke into kernel or any = process memory. >>> LSM is there to restrict processes running as "root". >> hmm. do you really mean that it's possible for an LSM to restrict CAP_= SYS_ADMIN effectively? I think that SELinux works hard to do just that. SELinux implements it's = own privilege model that is tangential to the capabilities model. More directly, it is simple to create a security module to provide finer = privilege granularity than capabilities. I have one lurking in a source tree, and I= would be surprised if it's the only one waiting for the next round of LSM stack= ing. >> LSM can certainly provide extra level of foolproof-ness against accide= ntal >> mistakes, but it's not a security boundary. Gasp! Them's fight'n words. How do you justify such an outrageous claim? >>> Your "root can poke into kernel or any process memory." response is o= ut of step with the times. >>> >>> Initial byte array used for usermode blob might be protected because = of "part of .rodata or >>> .init.rodata of kernel module", but that byte array after started in = userspace is no longer >>> protected.=20 >>> >>> I don't trust such byte array as "part of kernel module", and I'm ask= ing you how >>> such byte array does not interfere (or be interfered by) the rest of = the system. >> Could you please explain the attack vector that you see in such scenar= io? >> How elf binaries embedded in the kernel modules different from pid 1? >> If anything can peek into their memory the system is compromised. >> Say, there are no user blobs in kernel modules. How pid 1 memory is di= fferent >> from all the JITed images? How is it different for all memory regions = shared >> between kernel and user processes? >> I see an opportunity for an LSM to provide a protection against non-se= curity >> bugs when system is running trusted apps, but not when arbitrary code = can >> execute under root. >>