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[209.85.128.49]) by smtp.gmail.com with ESMTPSA id m6sm1050164ejb.51.2020.03.03.07.50.04 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 03 Mar 2020 07:50:04 -0800 (PST) Received: by mail-wm1-f49.google.com with SMTP id a25so2662611wmm.0 for ; Tue, 03 Mar 2020 07:50:04 -0800 (PST) X-Received: by 2002:a7b:c416:: with SMTP id k22mr4837344wmi.88.1583250223087; Tue, 03 Mar 2020 07:43:43 -0800 (PST) MIME-Version: 1.0 References: <20200228000105.165012-1-thgarnie@chromium.org> <202003022100.54CEEE60F@keescook> <20200303095514.GA2596@hirez.programming.kicks-ass.net> In-Reply-To: <20200303095514.GA2596@hirez.programming.kicks-ass.net> From: Thomas Garnier Date: Tue, 3 Mar 2020 07:43:31 -0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v11 00/11] x86: PIE support to extend KASLR randomization To: Peter Zijlstra Cc: Kees Cook , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Kernel Hardening , Kristen Carlson Accardi , Herbert Xu , "David S. Miller" , "H. Peter Anvin" , "the arch/x86 maintainers" , Andy Lutomirski , Juergen Gross , Thomas Hellstrom , "VMware, Inc." , "Rafael J. Wysocki" , Len Brown , Pavel Machek , Rasmus Villemoes , Miguel Ojeda , Will Deacon , Ard Biesheuvel , Masami Hiramatsu , Jiri Slaby , Boris Ostrovsky , Josh Poimboeuf , Cao jin , Allison Randal , Linux Crypto Mailing List , LKML , virtualization@lists.linux-foundation.org, Linux PM list 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 Tue, Mar 3, 2020 at 1:55 AM Peter Zijlstra wrote: > > On Mon, Mar 02, 2020 at 09:02:15PM -0800, Kees Cook wrote: > > On Thu, Feb 27, 2020 at 04:00:45PM -0800, Thomas Garnier wrote: > > > Minor changes based on feedback and rebase from v10. > > > > > > Splitting the previous serie in two. This part contains assembly code > > > changes required for PIE but without any direct dependencies with the > > > rest of the patchset. > > > > > > Note: Using objtool to detect non-compliant PIE relocations is not yet > > > possible as this patchset only includes the simplest PIE changes. > > > Additional changes are needed in kvm, xen and percpu code. > > > > > > Changes: > > > - patch v11 (assembly); > > > - Fix comments on x86/entry/64. > > > - Remove KASLR PIE explanation on all commits. > > > - Add note on objtool not being possible at this stage of the patchset. > > > > This moves us closer to PIE in a clean first step. I think these patches > > look good to go, and unblock the work in kvm, xen, and percpu code. Can > > one of the x86 maintainers pick this series up? > > But,... do we still need this in the light of that fine-grained kaslr > stuff? > > What is the actual value of this PIE crud in the face of that? If I remember well, it makes it easier/better but I haven't seen a recent update on that. Is that accurate Kees?