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=-8.3 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_IN_DEF_DKIM_WL 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 2A469C35247 for ; Thu, 6 Feb 2020 19:28:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F1FAD21775 for ; Thu, 6 Feb 2020 19:28:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="rvfROt3n" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727872AbgBFT2O (ORCPT ); Thu, 6 Feb 2020 14:28:14 -0500 Received: from mail-ot1-f65.google.com ([209.85.210.65]:47094 "EHLO mail-ot1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727698AbgBFT2O (ORCPT ); Thu, 6 Feb 2020 14:28:14 -0500 Received: by mail-ot1-f65.google.com with SMTP id g64so6585044otb.13 for ; Thu, 06 Feb 2020 11:28:12 -0800 (PST) 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=PPzXTmDRqSItJwjA4stEZr45/Nmk9dtQCp0t0GcfvJw=; b=rvfROt3nBVHeNCQfPYWwuOMBfp5sQZIqkXiywCwoSlbuLD0R8zkM8I/44uAiL/SsWG m8pc4hnzhgAK7O7L9Mm0YtzToA4+uNCENjfatqKVEHKStfKAnwMD4IWW7jHLRQikdM9a QJsAft3GrJ6L4V0NEvCvWSIXW0n6YGuCLzvZUfoSNUXAozdf2Vmo01BVSUvel13iFfOV 69wXY7b+REnUDlrLcBKbNwTH9NJhbfMsmO1PE3DYyzdQTiCvNH1RsZucMAwq8qvUXXW3 LZDAShSyOYZQgIpYGlMYQAd/U72LOUhUYpHMb+S8g6auBLeO5B7nblSGM5a6u9TbkR7i jBkA== 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=PPzXTmDRqSItJwjA4stEZr45/Nmk9dtQCp0t0GcfvJw=; b=i6DlYBRN7kaGL7j9Q6SNcR4TB+6tWdBHDbB+8PbwFxjPqr2dIV67/mrBWl3rnQhguD G8JxxuC6xlAUbPIQ9NRTRJu4XLtYbikARd3reLT5PF98ey8WIQqEcwKrCoAR3mw4S4Fp baHExL2fFNhUohrkKOnVJNt8r1/LXCB/lTp69dl1jfGfoo6klkuGQ4JIxcEfMIAFLf2H anra8XqNtJ7Gwjz3gn5/NnycYNglUQeRRsGDgz5jEl1A1T1p41RlZdq7FGmzyzB8butC vOxHTEZV8PKYS78CZSl0Hf/Da7FV6beARupRXsxqBR6KqREtok7n6sfIZjsP7TkR3qg+ 1a9w== X-Gm-Message-State: APjAAAUyAvLFzS2YgScZ6S7vDy3b00hQcW9hap8i5CvEeODKetbZJQHz jDb/+JwWcsTKBpnsxsVy27EpQZzsF4b2MUaFWqJp1w== X-Google-Smtp-Source: APXvYqwapGv/xZdFoWT4kXntbEcAkmogFT8Lk8w4susmDyaYarkU1eo5zWOTQAKb9bTDmLS5csh5ZQ5ckZLHFH+u4w8= X-Received: by 2002:a05:6830:22cc:: with SMTP id q12mr32387120otc.110.1581017291747; Thu, 06 Feb 2020 11:28:11 -0800 (PST) MIME-Version: 1.0 References: <20200205223950.1212394-1-kristen@linux.intel.com> <20200205223950.1212394-10-kristen@linux.intel.com> <202002060428.08B14F1@keescook> In-Reply-To: From: Jann Horn Date: Thu, 6 Feb 2020 20:27:45 +0100 Message-ID: Subject: Re: [RFC PATCH 09/11] kallsyms: hide layout and expose seed To: Kristen Carlson Accardi Cc: Kees Cook , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H . Peter Anvin" , Arjan van de Ven , Rick Edgecombe , "the arch/x86 maintainers" , kernel list , Kernel Hardening Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Feb 6, 2020 at 6:51 PM Kristen Carlson Accardi wrote: > On Thu, 2020-02-06 at 04:32 -0800, Kees Cook wrote: > > In the past, making kallsyms entirely unreadable seemed to break > > weird > > stuff in userspace. How about having an alternative view that just > > contains a alphanumeric sort of the symbol names (and they will > > continue > > to have zeroed addresses for unprivileged users)? > > > > Or perhaps we wait to hear about this causing a problem, and deal > > with > > it then? :) > > > > Yeah - I don't know what people want here. Clearly, we can't leave > kallsyms the way it is. Removing it entirely is a pretty fast way to > figure out how people use it though :). FYI, a pretty decent way to see how people are using an API is codesearch.debian.net, which searches through the source code of all the packages debian ships: https://codesearch.debian.net/search?q=%2Fproc%2Fkallsyms&literal=1