From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Tue, 25 Jun 2019 13:08:07 -0700 From: Kees Cook Message-ID: <201906251131.419D8ACB@keescook> References: <87v9wty9v4.fsf@oldenburg2.str.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87v9wty9v4.fsf@oldenburg2.str.redhat.com> Sender: linux-api-owner@vger.kernel.org Subject: Re: Detecting the availability of VSYSCALL Content-Transfer-Encoding: 8bit To: Florian Weimer Cc: linux-api@vger.kernel.org, kernel-hardening@lists.openwall.com, linux-x86_64@vger.kernel.org, linux-arch@vger.kernel.org, Andy Lutomirski , Carlos O'Donell List-ID: On Tue, Jun 25, 2019 at 05:15:27PM +0200, Florian Weimer wrote: > Should we try mapping something at the magic address (without MAP_FIXED) > and see if we get back a different address? Something in the auxiliary > vector would work for us, too, but nothing seems to exists there > unfortunately. It seems like mmap() won't even work because it's in the high memory area. I can't map something a page under the vsyscall page either, so I can't distinguish it with mmap, mprotect, madvise, or msync. :( -- Kees Cook