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=-11.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, 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 706E7CA9EA9 for ; Fri, 18 Oct 2019 17:55:01 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id B8D0921835 for ; Fri, 18 Oct 2019 17:55:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="NFaKn8K/" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B8D0921835 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernel-hardening-return-17052-kernel-hardening=archiver.kernel.org@lists.openwall.com Received: (qmail 13416 invoked by uid 550); 18 Oct 2019 17:54:37 -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 23949 invoked from network); 18 Oct 2019 17:11:39 -0000 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=XATsmiiQ65kT4ODqJ8G67gOZ75F3gzeYi1y9XLQaIlM=; b=NFaKn8K/6s2O1InStTL9sLz1AskGb0puzLhWcn2tdgY8ZmCLY7XOJRYveX8vbFZU0f AivKBQvkf/pODzLL5A4lcri/koO4kVh6iykeyqn4iKMkTaY1LVSs0gwEl9DJOigy8q8Q WPtHpYV0+uIe6amcTjkQLuADzSGPUx4rs/QmPrhO0WC+aS/VPjA8tDxGnOE6xkLGpQLv lTimTCE/K9U0RF4C039OIDi0j2iIowkJYeW6TPrBZBYFSBCJ9uXp+uP1gTWL63kz/VIn F7pEhz3ucREkKYmQDI91cCQ4B4+VGr1SMl0Byq8KA2sUVL6ZDahv6K/J2fUilePUK8ER 3UWw== 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=XATsmiiQ65kT4ODqJ8G67gOZ75F3gzeYi1y9XLQaIlM=; b=p+QIgNfrrsiM28r2O3rVCGKmbE8jwV4LZVi5C91PeN6U7DrVCp6FSeNSeUkQyRIGUW la3osIvfA49lSC/hCk/T+IlOqcVBJhuqqfdLwqORivk9FU7cOTW9P4FoZI2mftrxqlqG d7Rq2FKbBupisaozp3cMd3lUInOvpXyxukReTWHyaQIK9JIDH4xmb64UmdJnhAMJWccx kdMSL6XEzujQ9SOa+lClOzVl/ZpN23RXQWNWgjKFlwR4XGYmy0PaOIzjmRqRZh4vdPfO eA7YNSk3ZF5a1yv/ZuaFAtjCXOfU8Icod2X9Xx4LFhoKfMjRm9lmehW/bjK5a3ueYq2V rVCg== X-Gm-Message-State: APjAAAW9NFyn8lghHI59dM5TaYuNSOF/pBnyYKhGX7T8Dn23q5yQ/P13 qVl3IZRw/zuni/18JzD3bdvP5sDnnC9bc3BuV9Rpcw== X-Google-Smtp-Source: APXvYqxbFqx52fMmsudugE6XC0yz5SmZysXaFv9YWU7egAQ4sBR35UABj4n5x4ayDTqcJ+9yTIIHMtatlqnJPxGnKEw= X-Received: by 2002:a67:ed8b:: with SMTP id d11mr6025118vsp.104.1571418687239; Fri, 18 Oct 2019 10:11:27 -0700 (PDT) MIME-Version: 1.0 References: <20191018161033.261971-1-samitolvanen@google.com> <20191018161033.261971-7-samitolvanen@google.com> In-Reply-To: From: Sami Tolvanen Date: Fri, 18 Oct 2019 10:11:16 -0700 Message-ID: Subject: Re: [PATCH 06/18] add support for Clang's Shadow Call Stack (SCS) To: Nick Desaulniers Cc: Will Deacon , Catalin Marinas , Steven Rostedt , Ard Biesheuvel , Dave Martin , Kees Cook , Laura Abbott , Mark Rutland , clang-built-linux , Kernel Hardening , Linux ARM , LKML , Miguel Ojeda Content-Type: text/plain; charset="UTF-8" On Fri, Oct 18, 2019 at 10:08 AM 'Nick Desaulniers' via Clang Built Linux wrote: > > diff --git a/include/linux/compiler-clang.h b/include/linux/compiler-clang.h > > index 333a6695a918..9af08391f205 100644 > > --- a/include/linux/compiler-clang.h > > +++ b/include/linux/compiler-clang.h > > @@ -42,3 +42,5 @@ > > * compilers, like ICC. > > */ > > #define barrier() __asm__ __volatile__("" : : : "memory") > > + > > +#define __noscs __attribute__((no_sanitize("shadow-call-stack"))) > > It looks like this attribute, (and thus a requirement to use this > feature), didn't exist until Clang 7.0: https://godbolt.org/z/p9u1we > (as noted above) > > I think it's better to put __noscs behind a __has_attribute guard in > include/linux/compiler_attributes.h. Otherwise, what will happen when > Clang 6.0 sees __noscs, for example? (-Wunknown-sanitizers will > happen). Good point, I'll fix this in v2. Thanks. Sami