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=-8.6 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=ham 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 9F907C43381 for ; Thu, 28 Mar 2019 18:08:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6F4F020700 for ; Thu, 28 Mar 2019 18:08:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="NzaIE6ux" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726751AbfC1SIL (ORCPT ); Thu, 28 Mar 2019 14:08:11 -0400 Received: from mail-it1-f196.google.com ([209.85.166.196]:38488 "EHLO mail-it1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726916AbfC1SIL (ORCPT ); Thu, 28 Mar 2019 14:08:11 -0400 Received: by mail-it1-f196.google.com with SMTP id f22so7574807ita.3 for ; Thu, 28 Mar 2019 11:08:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=mhh689jASFqwg5CvKSsCVL3z97Hnu8T15rPfSQcYnLE=; b=NzaIE6uxYbEDkPgRduGRI2AmLoA943ZKQwON8MKRRwREEvb5qNVErkZCYnkweT35XG e/O50ZrnBInnKAyC64xIr32xixDaFfMBKPnppk60M3Z7IhKhmnk67EraFP20e5+8nrrq u7x2D0n6yzuz6kVMulwBnHknl0YxdSQseu0SDRAQ9jkC3E22SlWVHt/iiW47AXTfR5WZ DW4uHzhy1IVQV4n3rBuDUBPFrYo1Tqkksa02PunTAKwn+pffrTVlejqP3HWdmf0fI5b4 K4a+K8+DLDH1prvJEI240MgQMecSe+I7Zit4ejZ5jACKbSpX9hc9ROI9L7OagEDqsYFe 6OuQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=mhh689jASFqwg5CvKSsCVL3z97Hnu8T15rPfSQcYnLE=; b=F9hDwjgGzQCmWJbpE6ml+GkANWrzHGko214VgozM5Q9FGWCxTpKedtfccPGggDrpgV Pndqsdk+RTzC7ONQJHaWA1y6rNeb1KqVHQsdDTdiWFbO1h/6J898olOqlgzIq/apuxmv DDmBCAnyjCgkgMIUXjfPZlPKoAkIDyo3OE5zco8Dm4n2yl+bUKz96tCNzS9w9XtLjzKZ kif0DIMpGduQpGnU1fQv2MG1jGanxpbXn0OULRmSUpHFI7ILyO+a35k7sjwAEfhw6WR1 Ysg1wPDKZ108ZnlnR6/y5f2SrnuSA1fEySv0UuEiFUa2hxC5WbNf+B8Ate/zG8j2ljHY 1xEg== X-Gm-Message-State: APjAAAX17WAgN/Boqe/em3FQ7b5DoXsI1Ga262wREWxJBwsjHVtAmlhE waO3a9kjP51tX682kzDaTq55ac6okaAPe2e2VCQkCQ== X-Google-Smtp-Source: APXvYqw0Yrl3ZUNwrlKzql9TEGxfkebPkeGnm+q1biuWu2OO1H/hFDzrOmoZ0cn9r/fiozl40FPBUnC8VmVOXNlu6HI= X-Received: by 2002:a02:3d84:: with SMTP id n126mr26134078jan.102.1553796489486; Thu, 28 Mar 2019 11:08:09 -0700 (PDT) MIME-Version: 1.0 References: <20190325220954.29054-1-matthewgarrett@google.com> <20190325220954.29054-24-matthewgarrett@google.com> <20190325164221.5d8687bd@shemminger-XPS-13-9360> In-Reply-To: From: Matthew Garrett Date: Thu, 28 Mar 2019 11:07:58 -0700 Message-ID: Subject: Re: [PATCH 23/27] bpf: Restrict kernel image access functions when the kernel is locked down To: James Morris Cc: Andy Lutomirski , Stephen Hemminger , Linux API , LSM List , LKML , David Howells , Alexei Starovoitov , Network Development , Chun-Yi Lee , Daniel Borkmann , Kees Cook , Will Drewry Content-Type: text/plain; charset="UTF-8" Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: On Wed, Mar 27, 2019 at 8:15 PM James Morris wrote: > OTOH, this seems like a combination of mechanism and policy. The 3 modes > are a help here, but I wonder if they may be too coarse grained still, > e.g. if someone wants to allow a specific mechanism according to their own > threat model and mitigations. In general the interfaces blocked by these patches could also be blocked with an LSM, and I'd guess that people with more fine-grained requirements would probably take that approach. > Secure boot gives you some assurance of the static state of the system at > boot time, and lockdown is certainly useful (with or without secure boot), > but it's not a complete solution to runtime kernel integrity protection by > any stretch of the imagination. I'm concerned about it being perceived as > such. What do you think the functionality gaps are in terms of ensuring kernel integrity (other than kernel flaws that allow the restrictions to be bypassed)?