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=-8.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,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 637F0CA9ECF for ; Fri, 1 Nov 2019 16:28:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3538E20656 for ; Fri, 1 Nov 2019 16:28:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="ai3N6Ic4" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728763AbfKAQ2g (ORCPT ); Fri, 1 Nov 2019 12:28:36 -0400 Received: from mail-ua1-f65.google.com ([209.85.222.65]:33810 "EHLO mail-ua1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726701AbfKAQ2f (ORCPT ); Fri, 1 Nov 2019 12:28:35 -0400 Received: by mail-ua1-f65.google.com with SMTP id q16so3093806uao.1 for ; Fri, 01 Nov 2019 09:28:34 -0700 (PDT) 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=cugJW9F3kTAr1l84/vLpT5yr86XijpMcBnCXxXWK4UA=; b=ai3N6Ic4RRGuSAsXlls5IzMaslA5Wbr/HVntf4UgHRgBb1znSgpSqTQDhgWkXAk5oM H0TMkU5NqeJqmaviuucs+F/wv2mYGbxw4p/TlWjmTA7nxtnYoIewy1UZepA7s1zvqFi+ J0gxVuzM5VGToU0Rd8Mze3tyCLh7RZ7qRdkeI4u+x2bACiJuZjdPOS6PF5wclT402Cyl E4V47Z+G3JNyTOeTMcNM9nltwL7iNcdGY46YKNmZkjxzRh51T0x1vup1917ckL2zPFgG WhafP3q/o/Aolmq4VvLO1/E0Za4fVCa/z+d1jFfQQJXZNS7+zE2mjM1J0A4RaF2Z5bp3 En0Q== 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=cugJW9F3kTAr1l84/vLpT5yr86XijpMcBnCXxXWK4UA=; b=R0SPez6SqALJIX5Kho1egOJ8evo2hDwV5ApaPn9jm+g2o//vgPCl6/8WKul4M0xW+R 6SpdBxh6vy25XKIfuCibjsXhSX2O+/ZDYiW1cyn4cYwzH9sCMpMpZrTYsPi41/abr+FN vRICmcqGuFAEN5m/oOcdZOnzdSZNG/mvMuxnjiV5TtmUI4R/4M/fMAlPatP6mkpJyo6l Lz5GB62ISlL4msudC8O7MOsEjMzDVDihy7adoRVlxtiVv8KMp6OY7IwQSIvuvqoW8txP /JDEgQp1bnTXHGy0sMDXvQo2gusQspAPJBCne8PopoB5+VuQzwcu01KUgOoHjtTEiH+Z 2AMQ== X-Gm-Message-State: APjAAAVDIluvrwKLsZN/nCpdrsaspvfgT+PWUa7rwg2kyv+Tbu4eVQzy DPPMNf8GlYth7ukX7iH9CO7eXp4eUORnopIATPtfFg== X-Google-Smtp-Source: APXvYqz0PMfInUZYTnVA7QuGr/acGPXLqC8RP/nrNkyeFglf9nt3ZmPDMS4W5mUNYn60Yk/KFVXZFpuxRp6NFZg7Kqc= X-Received: by 2002:ab0:2381:: with SMTP id b1mr5975220uan.106.1572625713398; Fri, 01 Nov 2019 09:28:33 -0700 (PDT) MIME-Version: 1.0 References: <20191018161033.261971-1-samitolvanen@google.com> <20191031164637.48901-1-samitolvanen@google.com> <20191031164637.48901-6-samitolvanen@google.com> <201910312050.C538F8F3@keescook> In-Reply-To: <201910312050.C538F8F3@keescook> From: Sami Tolvanen Date: Fri, 1 Nov 2019 09:28:21 -0700 Message-ID: Subject: Re: [PATCH v3 05/17] add support for Clang's Shadow Call Stack (SCS) To: Kees Cook Cc: Will Deacon , Catalin Marinas , Steven Rostedt , Masami Hiramatsu , Ard Biesheuvel , Dave Martin , Laura Abbott , Mark Rutland , Nick Desaulniers , Jann Horn , Miguel Ojeda , Masahiro Yamada , clang-built-linux , Kernel Hardening , linux-arm-kernel , LKML 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 Thu, Oct 31, 2019 at 8:51 PM Kees Cook wrote: > > +/* A random number to mark the end of the shadow stack. */ > > +#define SCS_END_MAGIC 0xaf0194819b1635f6UL > > Is 0xaf.... non-canonical for arm64? While "random", it should also > likely be an "impossible" value to find on the call stack. Agreed, and yes, this is non-canonical for arm64 and AFAIK all 64-bit architectures the kernel supports. I'll add a note about it. Sami 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=-0.8 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_ADSP_CUSTOM_MED,DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 A9BA9CA9ECF for ; Fri, 1 Nov 2019 16:28:43 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 65D2F20656 for ; Fri, 1 Nov 2019 16:28:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="pbnwUen9"; 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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=cugJW9F3kTAr1l84/vLpT5yr86XijpMcBnCXxXWK4UA=; b=QTZ1zI29TNfNorsx9mPhT+elGcRVkLEcDoDN0DxZ2ayrfMdlFMHRnICrXEMpWQYRJ1 R36jPkjiFIJjxrWTWAmMXEf+7PTtW9ASM1hh8WURCDVC2ZcLpJ1qWZaD6cbqqF6gBlfG /oYMmGA4xdWp6dHdRYSBT06knT8pVrAS71GRnExeCp68O42A4NUAorKIfGjWyD/TVLTv yQlvlX34bhJ2yzBlbXJTwAJTGQvYrXb7Um3cRQ0gI6paiqH5J9+pt/YdcOgbxiC3aYTl ZkWFzzhF9ALzTsmcdd9kBB3EJmxfZtkN+84/QCvNReUjlpBl+8zAYbrzWJA9//w3KOfQ Dxjw== X-Gm-Message-State: APjAAAVXDa2KrXRbHnVgULjAzEYgaPxOUqQnT/XoipkYPOzeU2J66dhC KvvJ5gnPOotbTed76BP+VumHhDiqqWeQdawxGiuRPg== X-Google-Smtp-Source: APXvYqz0PMfInUZYTnVA7QuGr/acGPXLqC8RP/nrNkyeFglf9nt3ZmPDMS4W5mUNYn60Yk/KFVXZFpuxRp6NFZg7Kqc= X-Received: by 2002:ab0:2381:: with SMTP id b1mr5975220uan.106.1572625713398; Fri, 01 Nov 2019 09:28:33 -0700 (PDT) MIME-Version: 1.0 References: <20191018161033.261971-1-samitolvanen@google.com> <20191031164637.48901-1-samitolvanen@google.com> <20191031164637.48901-6-samitolvanen@google.com> <201910312050.C538F8F3@keescook> In-Reply-To: <201910312050.C538F8F3@keescook> From: Sami Tolvanen Date: Fri, 1 Nov 2019 09:28:21 -0700 Message-ID: Subject: Re: [PATCH v3 05/17] add support for Clang's Shadow Call Stack (SCS) To: Kees Cook X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191101_092835_446100_F05C8013 X-CRM114-Status: GOOD ( 10.18 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , clang-built-linux , Ard Biesheuvel , Masahiro Yamada , Catalin Marinas , Jann Horn , Nick Desaulniers , LKML , Steven Rostedt , Miguel Ojeda , Masami Hiramatsu , Kernel Hardening , Laura Abbott , Will Deacon , Dave Martin , linux-arm-kernel Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, Oct 31, 2019 at 8:51 PM Kees Cook wrote: > > +/* A random number to mark the end of the shadow stack. */ > > +#define SCS_END_MAGIC 0xaf0194819b1635f6UL > > Is 0xaf.... non-canonical for arm64? While "random", it should also > likely be an "impossible" value to find on the call stack. Agreed, and yes, this is non-canonical for arm64 and AFAIK all 64-bit architectures the kernel supports. I'll add a note about it. Sami _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel 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=-8.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,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 AFA47CA9ECF for ; Fri, 1 Nov 2019 16:28:53 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id 0775221897 for ; Fri, 1 Nov 2019 16:28:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="ai3N6Ic4" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0775221897 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-17227-kernel-hardening=archiver.kernel.org@lists.openwall.com Received: (qmail 13887 invoked by uid 550); 1 Nov 2019 16:28:46 -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 13864 invoked from network); 1 Nov 2019 16:28:45 -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=cugJW9F3kTAr1l84/vLpT5yr86XijpMcBnCXxXWK4UA=; b=ai3N6Ic4RRGuSAsXlls5IzMaslA5Wbr/HVntf4UgHRgBb1znSgpSqTQDhgWkXAk5oM H0TMkU5NqeJqmaviuucs+F/wv2mYGbxw4p/TlWjmTA7nxtnYoIewy1UZepA7s1zvqFi+ J0gxVuzM5VGToU0Rd8Mze3tyCLh7RZ7qRdkeI4u+x2bACiJuZjdPOS6PF5wclT402Cyl E4V47Z+G3JNyTOeTMcNM9nltwL7iNcdGY46YKNmZkjxzRh51T0x1vup1917ckL2zPFgG WhafP3q/o/Aolmq4VvLO1/E0Za4fVCa/z+d1jFfQQJXZNS7+zE2mjM1J0A4RaF2Z5bp3 En0Q== 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=cugJW9F3kTAr1l84/vLpT5yr86XijpMcBnCXxXWK4UA=; b=QaSOKCKIObLDOnOoqW830cV4xXL9Lq38/nAB5++daaajaNuEqP/9auC+19gnlraKMR MtBeD/opk0Bdk1TyJBw4OtcauR552d/4RGWBT6rAEK6tMEgoTNoPqK4k0/Mom65TV52I H3KhYC4TNaZzHt8TCR7fxYpF4plStoqpTvJcRw/IUBbNm07kxD5L7UAXl5DePRQLcaNx OQqL6mzJudh9/kRPhcn5qZjeH9NvdsoNbN8EZoAogUqA7DRkoexxNHF5CfMVTuXVvH6C aA8xBUSOIu7GRAxywLCB+N6tqwYjjNgtOuIu93Sw08tVhspE+RqQBgyEh8zi0M74Qjqm EN0A== X-Gm-Message-State: APjAAAUM2Oh0Yy+rXJwJw16a+bWSJ7dLFYphg72hvQAj/CoMf1UoFZXi kqgq+Y2TgUu3a5xtdZEbxoBrfBIyQKyoybieeBf0bQ== X-Google-Smtp-Source: APXvYqz0PMfInUZYTnVA7QuGr/acGPXLqC8RP/nrNkyeFglf9nt3ZmPDMS4W5mUNYn60Yk/KFVXZFpuxRp6NFZg7Kqc= X-Received: by 2002:ab0:2381:: with SMTP id b1mr5975220uan.106.1572625713398; Fri, 01 Nov 2019 09:28:33 -0700 (PDT) MIME-Version: 1.0 References: <20191018161033.261971-1-samitolvanen@google.com> <20191031164637.48901-1-samitolvanen@google.com> <20191031164637.48901-6-samitolvanen@google.com> <201910312050.C538F8F3@keescook> In-Reply-To: <201910312050.C538F8F3@keescook> From: Sami Tolvanen Date: Fri, 1 Nov 2019 09:28:21 -0700 Message-ID: Subject: Re: [PATCH v3 05/17] add support for Clang's Shadow Call Stack (SCS) To: Kees Cook Cc: Will Deacon , Catalin Marinas , Steven Rostedt , Masami Hiramatsu , Ard Biesheuvel , Dave Martin , Laura Abbott , Mark Rutland , Nick Desaulniers , Jann Horn , Miguel Ojeda , Masahiro Yamada , clang-built-linux , Kernel Hardening , linux-arm-kernel , LKML Content-Type: text/plain; charset="UTF-8" On Thu, Oct 31, 2019 at 8:51 PM Kees Cook wrote: > > +/* A random number to mark the end of the shadow stack. */ > > +#define SCS_END_MAGIC 0xaf0194819b1635f6UL > > Is 0xaf.... non-canonical for arm64? While "random", it should also > likely be an "impossible" value to find on the call stack. Agreed, and yes, this is non-canonical for arm64 and AFAIK all 64-bit architectures the kernel supports. I'll add a note about it. Sami