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=-5.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 BCC36C10F27 for ; Mon, 9 Mar 2020 16:49:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9212C22522 for ; Mon, 9 Mar 2020 16:49:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="kkDM6ZUx" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727192AbgCIQte (ORCPT ); Mon, 9 Mar 2020 12:49:34 -0400 Received: from mail-pj1-f67.google.com ([209.85.216.67]:51486 "EHLO mail-pj1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726804AbgCIQte (ORCPT ); Mon, 9 Mar 2020 12:49:34 -0400 Received: by mail-pj1-f67.google.com with SMTP id y7so105036pjn.1 for ; Mon, 09 Mar 2020 09:49:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=bNoFPXhpvMiuUF7F+uekItlbOQGQEdKTXJsSJYz6wNk=; b=kkDM6ZUxQYSDcpRCzqXBzl6yRdTxqvu7JFcn1rImw8v+HOQq5uEy+Sz/qwy5/3C+s3 KUB+FBs5z4n/A5MqPulS4DKCuhgmvKIaNUHArlCnB0h/4FTfLx81RD+3NgPaOsTFI1sc Xht0fVFnt3MfGytquyliFmFlyCRFniOygfHi/nqq5EDEZIh0kzrbvrDR7LEVlhMc98eX 29sgNmh17iEBtwdaaw3GPVgxtwO9+CmG5NxPouEQhUPQ9nIeCFBa/YA5/1Cb1Wws7s7Y +vU04Kr5himrgDw19nt8CDZj7ZuERB70/bdH97/T6iWuj6uLbmoM8YruSAMB5TCOsPlb 8E3A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to:user-agent; bh=bNoFPXhpvMiuUF7F+uekItlbOQGQEdKTXJsSJYz6wNk=; b=laUvmWzMzPXvDDgmfLstkAGGpy+jCFI/IME8DKuHz3rlecad+Ptn4tEWZgbSoXEP6i A7HZdG6gTpI/0odOFfyr7OkW6yu6w5DOIcV/1sQcnH0TIvwX528ziNYfdWVHrFVg9Bm8 R6ZA5+VR6ZlwoBpfCCiTjIMM+haMlKki+EOkN5TgftVUgtZyaqRRLn57rpHaD0R07e2e rI2bPttY283u8xd0hOXqYGd7dpMKfJFmb/1sDDFcZ2EbYDrKraLJQNIamqJAAWcCOh7O jwUCH+Im/mS61czWGHEcYcQXu0r3qGrmnVwNZE5D65f8R7s7S6NrkNOPD3inGhGjUXq2 Rybg== X-Gm-Message-State: ANhLgQ28oE267IDiqooD23xqDZ/+7n3h55O+blxQ6LyGilbwB7mlO6Yq nmteIn4ByRTjlNpO3co0UfM= X-Google-Smtp-Source: ADFU+vt/onT9cxmuspJ5T+KCU952uWkieCbEwJO4adVK6fLUN8zSNRf6ArvXDJD1xRu8YQakUYup1A== X-Received: by 2002:a17:90b:1882:: with SMTP id mn2mr105796pjb.139.1583772573044; Mon, 09 Mar 2020 09:49:33 -0700 (PDT) Received: from localhost ([2600:1700:e321:62f0:329c:23ff:fee3:9d7c]) by smtp.gmail.com with ESMTPSA id k24sm42857301pgm.61.2020.03.09.09.49.32 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 09 Mar 2020 09:49:32 -0700 (PDT) Date: Mon, 9 Mar 2020 09:49:31 -0700 From: Guenter Roeck To: Ard Biesheuvel Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux@armlinux.org.uk, Kees Cook , Emese Revfy , Arnd Bergmann , Laura Abbott , kernel-hardening@lists.openwall.com Subject: Re: [PATCH v3] ARM: smp: add support for per-task stack canaries Message-ID: <20200309164931.GA23889@roeck-us.net> References: <20181206083257.9596-1-ard.biesheuvel@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181206083257.9596-1-ard.biesheuvel@linaro.org> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Dec 06, 2018 at 09:32:57AM +0100, Ard Biesheuvel wrote: > On ARM, we currently only change the value of the stack canary when > switching tasks if the kernel was built for UP. On SMP kernels, this > is impossible since the stack canary value is obtained via a global > symbol reference, which means > a) all running tasks on all CPUs must use the same value > b) we can only modify the value when no kernel stack frames are live > on any CPU, which is effectively never. > > So instead, use a GCC plugin to add a RTL pass that replaces each > reference to the address of the __stack_chk_guard symbol with an > expression that produces the address of the 'stack_canary' field > that is added to struct thread_info. This way, each task will use > its own randomized value. > > Cc: Russell King > Cc: Kees Cook > Cc: Emese Revfy > Cc: Arnd Bergmann > Cc: Laura Abbott > Cc: kernel-hardening@lists.openwall.com > Acked-by: Nicolas Pitre > Signed-off-by: Ard Biesheuvel Since this patch is in the tree, cc-option no longer works on the arm architecture if CONFIG_STACKPROTECTOR_PER_TASK is enabled. Any idea how to fix that ? Thanks, Guenter