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=-5.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,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 7B21BC433E0 for ; Tue, 4 Aug 2020 11:45:28 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id D35152075F for ; Tue, 4 Aug 2020 11:45:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="TcvSJ7XZ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D35152075F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernel-hardening-return-19550-kernel-hardening=archiver.kernel.org@lists.openwall.com Received: (qmail 28404 invoked by uid 550); 4 Aug 2020 11:45:20 -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 28103 invoked from network); 4 Aug 2020 00:48:43 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1596502111; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=pni1o6aoiUKtw/3OfYS97iO3vEt5WV4q/1D+eS1+IJs=; b=TcvSJ7XZ/BwwDWzS4tntOJEvnfaZtkSCUPTPJkAmfHFT++9BPmycVGyN3nmIFe3SLct4M8 3uwmlQA2QBrcGl0d8SPUTsohfqnx1Diq7euCgY1GJO2k4n2kjKFM4MoktnObUHN2ujm3AP Hf9Jr0wZOcz6FTNntPbCqwTAttUfXvg= X-MC-Unique: Q5lytYKUP--GAurLnuzXlQ-1 Date: Mon, 3 Aug 2020 20:48:17 -0400 From: "Frank Ch. Eigler" To: Kees Cook Cc: Joe Lawrence , Evgenii Shatokhin , Kristen Carlson Accardi , Miroslav Benes , tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, arjan@linux.intel.com, x86@kernel.org, linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com, rick.p.edgecombe@intel.com, live-patching@vger.kernel.org, Josh Poimboeuf , Jessica Yu Subject: Re: [PATCH v4 00/10] Function Granular KASLR Message-ID: <20200804004817.GD30810@redhat.com> References: <20200717170008.5949-1-kristen@linux.intel.com> <202008031043.FE182E9@keescook> <20200803193837.GB30810@redhat.com> <202008031310.4F8DAA20@keescook> <20200803211228.GC30810@redhat.com> <202008031439.F1399A588@keescook> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <202008031439.F1399A588@keescook> User-Agent: Mutt/1.12.0 (2019-05-25) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Hi - > > We have relocated based on sections, not some subset of function > > symbols accessible that way, partly because DWARF line- and DIE- based > > probes can map to addresses some way away from function symbols, into > > function interiors, or cloned/moved bits of optimized code. It would > > take some work to prove that function-symbol based heuristic > > arithmetic would have just as much reach. > > Interesting. Do you have an example handy? No, I'm afraid I don't have one that I know cannot possibly be expressed by reference to a function symbol only. I'd look at systemtap (4.3) probe point lists like: % stap -vL 'kernel.statement("*@kernel/*verif*.c:*")' % stap -vL 'module("amdgpu").statement("*@*execution*.c:*")' which give an impression of computed PC addresses. > It seems like something like that would reference the enclosing > section, which means we can't just leave them out of the sysfs > list... (but if such things never happen in the function-sections, > then we *can* remove them...) I'm not sure we can easily prove they can never happen there. - FChE