From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wr1-f51.google.com (mail-wr1-f51.google.com [209.85.221.51]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 675131D61AA for ; Tue, 5 Aug 2025 08:03:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.51 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754380986; cv=none; b=vACuLYxpwszvQQ1WhCJqzkOl9zkrr4GCTdbq82hGkujtJO/oJ4EEviuWANC+rtVIgq8drjIhzYfMVPq70JqM2cgU0ppYaRuhd50B7dv3pi/uGqViQvy99ndE3MRrzZNEj7uSxfbJtVTSPF5wRVBNGblgvkXrgLQqCDaIpkqGJ2Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754380986; c=relaxed/simple; bh=oQm/ztvGyOGwifmduBh40jvKEHQI6Sw3B8DUIu9PyT4=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=JTjcfJcgzPuriDHnPCaWAnbh2PQnYfEkA3wqbZ1wJoZO8wmasTOtOehKUZ5+CpnkX6u4r8BdwUXfL1CdqFMj4O/ASUOwPvMOxhSuh00EObEvaOG4x5IfCF6YzmI4+DyOeBCKGE+aVG+WKS+ryT5MUOUFNdfrVUgWyEVyAXpjk98= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com; spf=pass smtp.mailfrom=suse.com; dkim=pass (2048-bit key) header.d=suse.com header.i=@suse.com header.b=C1QsGGua; arc=none smtp.client-ip=209.85.221.51 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=suse.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=suse.com header.i=@suse.com header.b="C1QsGGua" Received: by mail-wr1-f51.google.com with SMTP id ffacd0b85a97d-3a6cd1a6fecso4462677f8f.3 for ; Tue, 05 Aug 2025 01:03:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=google; t=1754380983; x=1754985783; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:autocrypt:from :content-language:references:cc:to:subject:user-agent:mime-version :date:message-id:from:to:cc:subject:date:message-id:reply-to; bh=I+ANpje7dfs6pZ7qzQnGOwzuarpMyrDg5V24pULqjSc=; b=C1QsGGuaE1kPauyh3rEGbMJmlC+dcymNyu73rtoXjAzwM16mSUfC+bwje98fAeBvb6 vRqIwRskVI1lnY6s1HrtJF2uLmJ/7ZRptLqethwttfrV2VJxHleuYE9DN+4HGuDqeNsy kK1cWedA1jvYTm6ggYPrNhVb78yVCx81ygaX04BL7GSYj3KQG2gULBMNoNZ/RD9khliD jzyoCgI/ABK5PXZRFxduAZ/FiKq7v4YM7JnE6BU67SC12Wm7a3kfl8Nk8/8z5nVEphM7 FbhR133nhmX7mIViIhL9nYufH0407PdX2v4AP1Oe7t+EA74+JmdMHTwTWE5UisXaWGko GOIg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1754380983; x=1754985783; h=content-transfer-encoding:in-reply-to:autocrypt:from :content-language:references:cc:to:subject:user-agent:mime-version :date:message-id:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=I+ANpje7dfs6pZ7qzQnGOwzuarpMyrDg5V24pULqjSc=; b=QyosIQ5xdMaSNol3dfCW6u+5thJEuWEt6GvmppHgNvrxJuhAD0oMa2YFnvUultXFiQ 2qrZmLF//1j3qVZxgEx2Cb46LPrTlKUNvpkwEoMJrxNk98x0ya8L/7Z4kuBef68EnkJ9 tPw5BEVaxWobDU2ovek651jfSEIi00bx0OxNzYTe350bdmZ90PGZhulyFqChAo4W0Typ dscyt5aAb+1b7BAaqX2S+aEztzccR/FNPZq9lQpoNO04cHu2QD9p8GycGLr6KBznav1Q NLOvBiBaL7SMnOfSbvMVVYmpKOPlOY7PYSIp7MFZW8RlODywjkd3MWwjxnQBCIHHIY9C kF7A== X-Gm-Message-State: AOJu0YzGZcFDb/i61sh+jDBotudjCWpe8BweicKV71O/zx7ID/80wuku nWqWdpLIGjkAnGZ66MKXc1GUtk0jfZTBrCoOFaZ1QRA5E5SV/VtB3u03//2aCN7l3Q4= X-Gm-Gg: ASbGnctaqYnb0ElCr+PpAtFFSzt2pShJY0PoXi+p6WoJDSmOV2WWTIx68WQgGnE8QTe 53u6reTAVTF07GP7cblXz3pjVITCBwpa85L9I//0Rg73PDUKMx9URJASfZTydUtMBdLcZ97kwd5 8LE/fr2rjlvRcnZzK+wPqCaqTp2NhVSHLH1wKavOyq911tSdBp5puUdhBlmP1JanvgbXo5f7lYJ teJmOg70Rma+vPemq4kgGh/B4BIw8qwXg7s771ZmaT/+c9h8h9bIpFc3BinzyOSRkcWH0OqTWhK DtSUsY6x5lxxPli6LJ0GEW+vCULBS/gGFHVlUq0DQZCgJsY3DSA1/Tc4HrK2Gu32bwwC8kKbdgG uetUjDmK7lZ82ivnqQmeey/qvt/ndHNyeoikElvCy8AfBp4HVyw== X-Google-Smtp-Source: AGHT+IHMG6M7h+w11+BYMtMmX8WemVMsPXxcbMHZpgW5luIfhyB84aA+NcxV5dCTd4atZPw7v8raPg== X-Received: by 2002:a05:6000:4027:b0:3b6:936:976c with SMTP id ffacd0b85a97d-3b8d94720e7mr8536259f8f.17.1754380982575; Tue, 05 Aug 2025 01:03:02 -0700 (PDT) Received: from [192.168.0.20] (nborisov.ddns.nbis.net. [109.121.143.247]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-458b9159e00sm122794765e9.9.2025.08.05.01.03.01 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 05 Aug 2025 01:03:02 -0700 (PDT) Message-ID: <3be6b1c2-4b54-4107-8bdd-67d5cbcff58c@suse.com> Date: Tue, 5 Aug 2025 11:03:00 +0300 Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 0/3] Allow individual features to be locked down To: xiujianfeng , Nicolas Bouchinet Cc: linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, paul@paul-moore.com, serge@hallyn.com, jmorris@namei.org, dan.j.williams@intel.com References: <20250728111517.134116-1-nik.borisov@suse.com> <9b6fd06e-5438-4539-821c-6f3d5fa6b7d1@suse.com> <42b2cf1b-417e-1594-d525-f4c84f7405b0@huawei.com> Content-Language: en-US From: Nikolay Borisov Autocrypt: addr=nik.borisov@suse.com; keydata= xsFNBGcrpvIBEAD5cAR5+qu30GnmPrK9veWX5RVzzbgtkk9C/EESHy9Yz0+HWgCVRoNyRQsZ 7DW7vE1KhioDLXjDmeu8/0A8u5nFMqv6d1Gt1lb7XzSAYw7uSWXLPEjFBtz9+fBJJLgbYU7G OpTKy6gRr6GaItZze+r04PGWjeyVUuHZuncTO7B2huxcwIk9tFtRX21gVSOOC96HcxSVVA7X N/LLM2EOL7kg4/yDWEhAdLQDChswhmdpHkp5g6ytj9TM8bNlq9I41hl/3cBEeAkxtb/eS5YR 88LBb/2FkcGnhxkGJPNB+4Siku7K8Mk2Y6elnkOctJcDvk29DajYbQnnW4nhfelZuLNupb1O M0912EvzOVI0dIVgR+xtosp66bYTOpX4Xb0fylED9kYGiuEAeoQZaDQ2eICDcHPiaLzh+6cc pkVTB0sXkWHUsPamtPum6/PgWLE9vGI5s+FaqBaqBYDKyvtJfLK4BdZng0Uc3ijycPs3bpbQ bOnK9LD8TYmYaeTenoNILQ7Ut54CCEXkP446skUMKrEo/HabvkykyWqWiIE/UlAYAx9+Ckho TT1d2QsmsAiYYWwjU8igXBecIbC0uRtF/cTfelNGrQwbICUT6kJjcOTpQDaVyIgRSlUMrlNZ XPVEQ6Zq3/aENA8ObhFxE5PLJPizJH6SC89BMKF3zg6SKx0qzQARAQABzSZOaWtvbGF5IEJv cmlzb3YgPG5pay5ib3Jpc292QHN1c2UuY29tPsLBkQQTAQoAOxYhBDuWB8EJLBUZCPjT3SRn XZEnyhfsBQJnK6byAhsDBQsJCAcCAiICBhUKCQgLAgQWAgMBAh4HAheAAAoJECRnXZEnyhfs XbIQAJxuUnelGdXbSbtovBNm+HF3LtT0XnZ0+DoR0DemUGuA1bZAlaOXGr5mvVbTgaoGUQIJ 3Ejx3UBEG7ZSJcfJobB34w1qHEDO0pN9orGIFT9Bic3lqhawD2r85QMcWwjsZH5FhyRx7P2o DTuUClLMO95GuHYQngBF2rHHl8QMJPVKsR18w4IWAhALpEApxa3luyV7pAAqKllfCNt7tmed uKmclf/Sz6qoP75CvEtRbfAOqYgG1Uk9A62C51iAPe35neMre3WGLsdgyMj4/15jPYi+tOUX Tc7AAWgc95LXyPJo8069MOU73htZmgH4OYy+S7f+ArXD7h8lTLT1niff2bCPi6eiAQq6b5CJ Ka4/27IiZo8tm1XjLYmoBmaCovqx5y5Xt2koibIWG3ZGD2I+qRwZ0UohKRH6kKVHGcrmCv0J YO8yIprxgoYmA7gq21BpTqw3D4+8xujn/6LgndLKmGESM1FuY3ymXgj5983eqaxicKpT9iq8 /a1j31tms4azR7+6Dt8H4SagfN6VbJ0luPzobrrNFxUgpjR4ZyQQ++G7oSRdwjfIh1wuCF6/ mDUNcb6/kA0JS9otiC3omfht47yQnvod+MxFk1lTNUu3hePJUwg1vT1te3vO5oln8lkUo9BU knlYpQ7QA2rDEKs+YWqUstr4pDtHzwQ6mo0rqP+zzsFNBGcrpvIBEADGYTFkNVttZkt6e7yA LNkv3Q39zQCt8qe7qkPdlj3CqygVXfw+h7GlcT9fuc4kd7YxFys4/Wd9icj9ZatGMwffONmi LnUotIq2N7+xvc4Xu76wv+QJpiuGEfCDB+VdZOmOzUPlmMkcJc/EDSH4qGogIYRu72uweKEq VfBI43PZIGpGJ7TjS3THX5WVI2YNSmuwqxnQF/iVqDtD2N72ObkBwIf9GnrOgxEyJ/SQq2R0 g7hd6IYk7SOKt1a8ZGCN6hXXKzmM6gHRC8fyWeTqJcK4BKSdX8PzEuYmAJjSfx4w6DoxdK5/ 9sVrNzaVgDHS0ThH/5kNkZ65KNR7K2nk45LT5Crjbg7w5/kKDY6/XiXDx7v/BOR/a+Ryo+lM MffN3XSnAex8cmIhNINl5Z8CAvDLUtItLcbDOv7hdXt6DSyb65CdyY8JwOt6CWno1tdjyDEG 5ANwVPYY878IFkOJLRTJuUd5ltybaSWjKIwjYJfIXuoyzE7OL63856MC/Os8PcLfY7vYY2LB cvKH1qOcs+an86DWX17+dkcKD/YLrpzwvRMur5+kTgVfXcC0TAl39N4YtaCKM/3ugAaVS1Mw MrbyGnGqVMqlCpjnpYREzapSk8XxbO2kYRsZQd8J9ei98OSqgPf8xM7NCULd/xaZLJUydql1 JdSREId2C15jut21aQARAQABwsF2BBgBCgAgFiEEO5YHwQksFRkI+NPdJGddkSfKF+wFAmcr pvICGwwACgkQJGddkSfKF+xuuxAA4F9iQc61wvAOAidktv4Rztn4QKy8TAyGN3M8zYf/A5Zx VcGgX4J4MhRUoPQNrzmVlrrtE2KILHxQZx5eQyPgixPXri42oG5ePEXZoLU5GFRYSPjjTYmP ypyTPN7uoWLfw4TxJqWCGRLsjnkwvyN3R4161Dty4Uhzqp1IkNhl3ifTDYEvbnmHaNvlvvna 7+9jjEBDEFYDMuO/CA8UtoVQXjy5gtOhZZkEsptfwQYc+E9U99yxGofDul7xH41VdXGpIhUj 4wjd3IbgaCiHxxj/M9eM99ybu5asvHyMo3EFPkyWxZsBlUN/riFXGspG4sT0cwOUhG2ZnExv XXhOGKs/y3VGhjZeCDWZ+0ZQHPCL3HUebLxW49wwLxvXU6sLNfYnTJxdqn58Aq4sBXW5Un0Q vfbd9VFV/bKFfvUscYk2UKPi9vgn1hY38IfmsnoS8b0uwDq75IBvup9pYFyNyPf5SutxhFfP JDjakbdjBoYDWVoaPbp5KAQ2VQRiR54lir/inyqGX+dwzPX/F4OHfB5RTiAFLJliCxniKFsM d8eHe88jWjm6/ilx4IlLl9/MdVUGjLpBi18X7ejLz3U2quYD8DBAGzCjy49wJ4Di4qQjblb2 pTXoEyM2L6E604NbDu0VDvHg7EXh1WwmijEu28c/hEB6DwtzslLpBSsJV0s1/jE= In-Reply-To: <42b2cf1b-417e-1594-d525-f4c84f7405b0@huawei.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 8/5/25 09:57, xiujianfeng wrote: > > > On 2025/7/29 20:25, Nikolay Borisov wrote: >> >> >> On 29.07.25 г. 15:16 ч., Nicolas Bouchinet wrote: >>> Hi Nikolay, >>> >>> Thanks for you patch. >>> >>> Quoting Kees [1], Lockdown is "about creating a bright line between >>> uid-0 and ring-0". >>> >>> Having a bitmap enabled Lockdown would mean that Lockdown reasons could >>> be activated independently. I fear this would lead to a false sense of >>> security, locking one reason alone often permits Lockdown restrictions >>> bypass. i.e enforcing kernel module signature verification but not >>> blocking accesses to `/dev/{k,}mem` or authorizing gkdb which can be >>> used to disable the module signature enforcement. >>> >>> If one wants to restrict accesses to `/dev/mem`, >>> `security_locked_down(LOCKDOWN_DEV_MEM)` should be sufficient. >>> >>> My understanding of your problem is that this locks too much for your >>> usecase and you want to restrict reasons of Lockdown independently in >>> case it has not been enabled in "integrity" mode by default ? >>> >>> Can you elaborate more on the usecases for COCO ? >> >> Initially this patchset was supposed to allow us selectively disable >> /dev/iomem access in a CoCo context [0]. As evident from Dan's initial >> response that point pretty much became moot as the issue was fixed in a >> different way. However, later [1] he came back and said that actually >> this patch could be useful in a similar context. So This v2 is >> essentially following up on that. > > Hi Nikolay, > > I share a similar view with Nicolas, namely that using a bitmap > implementation would compromise the goal of Lockdown. > > After reading the threads below, I understand you aim is to block user > access to /dev/mem, but without having Lockdown integrity mode enabled > to block other reasons, right? How about using BPF LSM? It seems it > could address your requirements. > Well the use case that my change allows (barring the original issue) is say if someone wants LOCKDOWN_INTEGRITY_MAX + 1 or 2 things from the CONFIDENTIALY_MAX level. >> >> >> [0] >> https://lore.kernel.org/all/67f69600ed221_71fe2946f@dwillia2-xfh.jf.intel.com.notmuch/ >> >> [1] >> https://lore.kernel.org/all/68226ad551afd_29032945b@dwillia2-xfh.jf.intel.com.notmuch/ >> >>