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 5333DC33CAF for ; Thu, 16 Jan 2020 21:58:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1EDDE20728 for ; Thu, 16 Jan 2020 21:58:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="VNVb2CG8" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388251AbgAPV6G (ORCPT ); Thu, 16 Jan 2020 16:58:06 -0500 Received: from mail-vs1-f67.google.com ([209.85.217.67]:34361 "EHLO mail-vs1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729380AbgAPV6G (ORCPT ); Thu, 16 Jan 2020 16:58:06 -0500 Received: by mail-vs1-f67.google.com with SMTP id g15so13691680vsf.1 for ; Thu, 16 Jan 2020 13:58:05 -0800 (PST) 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=90kSKrsPpbCluN0U4RDiVNxyzvDrsXuzgr4VAEgKFuc=; b=VNVb2CG8c3HkjMqddLo98y3OPZa+WSPTAgoYdSf7FbWI5WNi3wnlLK0p32BzwbDJkl DxW3dVwqqXEzvQDJ/t2t8XVh7UcdBnxl57fQBAwB07GY+Kc5s2di8Ti7bcTy/S2/pe8U ishyY7KqIu0u9X9VZYcJD0ArT3LnkwpSs93Icdin/XOuAUh49RrudpoY+q52GTTYSx40 GpnMdqP6bRbODHeQRjbKNwwaXhmlW1mB68/yoKkEelegSKWRaD4DkiQa+ct5BY9CQ8b+ WhW5jUQJ1e+6OM3m0IRmGb8dXhOkx9FNog8QbWSOqQkVjep7R9pRuyilDTthUXsbS/HD LriA== 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=90kSKrsPpbCluN0U4RDiVNxyzvDrsXuzgr4VAEgKFuc=; b=KEkNnaUhOKkzLdXcA5i1GVSycc9i45LRPAvjr+qjJzrmWSTEF7m9/sSXS9XDKwKqDm bDcu1UF/MS6VcAJ7jdLhik9v4KeYQH0wux/mc59T8Ig6VZbF8Wnm0u81z4tSNKnmSzg/ Z7M2y7p/0K8g59dvL1950+GMvBuKlcSeM7vBVywVi6ikS5UCvZG98MfvbPHI2+gY0IM8 +hI3z3QMMGdh0zOytrLpuchhTuyZ+p5mxtyIleBQ8AiP8elREM4tE347X9K+5+ihbfn1 678JX6R6WiyZF4PMYnUaXZbImydQk3KyfPCqmsj5gozednWCDlGboNr6Zo9oCTTuE1DM Iw6A== X-Gm-Message-State: APjAAAUaK2LCpOKRi1iXk31gCJK/6V1kw8qSa9/BkEUeRWRepEfBEi5H k6aPW0CG/SckVQH/oAOtXzBNDzYnDRAFBUFt4dQs6w== X-Google-Smtp-Source: APXvYqzrUqH5/W2UZ+FeXG0hZr7Tack1J9k9eB9pBix6w41rOK+OkTqsOrnRDdc5aMPEGFoHQeXxcn/0tewoHbFlgSg= X-Received: by 2002:a67:ae43:: with SMTP id u3mr3413809vsh.44.1579211884786; Thu, 16 Jan 2020 13:58:04 -0800 (PST) MIME-Version: 1.0 References: <20191018161033.261971-1-samitolvanen@google.com> <20191206221351.38241-1-samitolvanen@google.com> <20191206221351.38241-15-samitolvanen@google.com> <20200116182414.GC22420@willie-the-truck> In-Reply-To: <20200116182414.GC22420@willie-the-truck> From: Sami Tolvanen Date: Thu, 16 Jan 2020 13:57:53 -0800 Message-ID: Subject: Re: [PATCH v6 14/15] arm64: implement Shadow Call Stack To: Will Deacon Cc: Catalin Marinas , Steven Rostedt , Masami Hiramatsu , Ard Biesheuvel , Mark Rutland , Dave Martin , Kees Cook , Laura Abbott , Marc Zyngier , 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, Jan 16, 2020 at 10:24 AM Will Deacon wrote: > > .macro irq_stack_entry > > mov x19, sp // preserve the original sp > > +#ifdef CONFIG_SHADOW_CALL_STACK > > + mov x20, x18 // preserve the original shadow stack > > +#endif > > Hmm, not sure about corrupting x20 here. Doesn't it hold the PMR value from > kernel_entry? You're right, and it's used in el1_irq after irq_handler if CONFIG_ARM64_PSEUDO_NMI is enabled. Thanks for pointing this out. Looks like one of x24-x29 should be safe here, and the comment needs to be updated to explain why x20-x23 shouldn't be corrupted. 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 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 7BCDAC33CAF for ; Thu, 16 Jan 2020 21:58:15 +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 49A1620728 for ; Thu, 16 Jan 2020 21:58:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="LhS0Exds"; dkim=fail reason="signature verification failed" (2048-bit key) header.d=google.com header.i=@google.com header.b="VNVb2CG8" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 49A1620728 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:To:Subject:Message-ID:Date:From: In-Reply-To:References:MIME-Version:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=tPAsRAXcImnabhoVWVjfxSJ1aPK7hXHJLgNLbZ+X5OQ=; b=LhS0ExdsN7VtJf WGeCu1YZFWSmrLx0yj/yeO8FVcfaW0Jm9EWUneUfaBSaO+XUlcLIl5oFUVlXDjtcFfM2VaGgwaMSc IeXkH2zISMampp+lcEieWmDEj3OrB/SAkKT/BbINnlGPrDyGcF8scGPoWO3JtLyJ4IZsYMx06vazn nnifDySlvKiIddRKRVkEpKsw+Sc2HC/C0MmhHmQs+3Y/3VpwVlvFi6XeQ5eZgeqt0K3spQb+qt76s 9daOL3oQfvIf1xrZXrCsVoFLQkXVEzUePrszsxT7L4bHhVN2x5t6NehW+mxwtwgZZQ9heWsPU/ps7 LbBGaOEQMJowoEFbl4OA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1isD9W-0005Fk-HR; Thu, 16 Jan 2020 21:58:10 +0000 Received: from mail-vs1-xe41.google.com ([2607:f8b0:4864:20::e41]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1isD9T-0005F7-Vr for linux-arm-kernel@lists.infradead.org; Thu, 16 Jan 2020 21:58:09 +0000 Received: by mail-vs1-xe41.google.com with SMTP id p6so13657910vsj.11 for ; Thu, 16 Jan 2020 13:58:05 -0800 (PST) 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=90kSKrsPpbCluN0U4RDiVNxyzvDrsXuzgr4VAEgKFuc=; b=VNVb2CG8c3HkjMqddLo98y3OPZa+WSPTAgoYdSf7FbWI5WNi3wnlLK0p32BzwbDJkl DxW3dVwqqXEzvQDJ/t2t8XVh7UcdBnxl57fQBAwB07GY+Kc5s2di8Ti7bcTy/S2/pe8U ishyY7KqIu0u9X9VZYcJD0ArT3LnkwpSs93Icdin/XOuAUh49RrudpoY+q52GTTYSx40 GpnMdqP6bRbODHeQRjbKNwwaXhmlW1mB68/yoKkEelegSKWRaD4DkiQa+ct5BY9CQ8b+ WhW5jUQJ1e+6OM3m0IRmGb8dXhOkx9FNog8QbWSOqQkVjep7R9pRuyilDTthUXsbS/HD LriA== 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=90kSKrsPpbCluN0U4RDiVNxyzvDrsXuzgr4VAEgKFuc=; b=FjpPdqI+flocRiIk9hT/mOyS8QWdzMyq2kUX0w5B0sViCKuNXPNWvKdg5C5ZGlGeFd ZbmrQMgDD+PE6BH9S1FEBMkWum7ef0y8mUSA2FtreXpBCx6RnVjDnZszXYarhvSjfZ5g Wjf6WL9ZtE6uBuKKv5fUvpmx3oC3Yj/Hiy5Zq+TA6pSSYOXN2wabfMTD6twYjhErUjfh e10opre1fa+26/Z0tSEQHqdK+9ztxVlrIXQBjSpmYsCeT2Shw1ZdUKw2jRXaH4oYoSXX C2bKeeOXvjNQ1WiNpS7IuHpWHjt1cWu6EHW4YElX2ooFDWgflJOEyeNabJrZzMRAFC6n X6zA== X-Gm-Message-State: APjAAAWSFdppGRv6gHDFfrO3ILydLeO8MshB5utBdONDHsX4ROybLddX RAvWxiRp4gqTgARUHbIN7euhlGIZTW7GrViTuG7tvQ== X-Google-Smtp-Source: APXvYqzrUqH5/W2UZ+FeXG0hZr7Tack1J9k9eB9pBix6w41rOK+OkTqsOrnRDdc5aMPEGFoHQeXxcn/0tewoHbFlgSg= X-Received: by 2002:a67:ae43:: with SMTP id u3mr3413809vsh.44.1579211884786; Thu, 16 Jan 2020 13:58:04 -0800 (PST) MIME-Version: 1.0 References: <20191018161033.261971-1-samitolvanen@google.com> <20191206221351.38241-1-samitolvanen@google.com> <20191206221351.38241-15-samitolvanen@google.com> <20200116182414.GC22420@willie-the-truck> In-Reply-To: <20200116182414.GC22420@willie-the-truck> From: Sami Tolvanen Date: Thu, 16 Jan 2020 13:57:53 -0800 Message-ID: Subject: Re: [PATCH v6 14/15] arm64: implement Shadow Call Stack To: Will Deacon X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200116_135808_050261_B2B06A06 X-CRM114-Status: UNSURE ( 8.14 ) X-CRM114-Notice: Please train this message. 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 , Kees Cook , Ard Biesheuvel , Masahiro Yamada , Catalin Marinas , Jann Horn , Nick Desaulniers , LKML , Steven Rostedt , Miguel Ojeda , clang-built-linux , Masami Hiramatsu , Marc Zyngier , Kernel Hardening , Laura Abbott , 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, Jan 16, 2020 at 10:24 AM Will Deacon wrote: > > .macro irq_stack_entry > > mov x19, sp // preserve the original sp > > +#ifdef CONFIG_SHADOW_CALL_STACK > > + mov x20, x18 // preserve the original shadow stack > > +#endif > > Hmm, not sure about corrupting x20 here. Doesn't it hold the PMR value from > kernel_entry? You're right, and it's used in el1_irq after irq_handler if CONFIG_ARM64_PSEUDO_NMI is enabled. Thanks for pointing this out. Looks like one of x24-x29 should be safe here, and the comment needs to be updated to explain why x20-x23 shouldn't be corrupted. 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,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 8623AC33CAF for ; Thu, 16 Jan 2020 21:58:23 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id D19B320728 for ; Thu, 16 Jan 2020 21:58:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="VNVb2CG8" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D19B320728 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-17582-kernel-hardening=archiver.kernel.org@lists.openwall.com Received: (qmail 19856 invoked by uid 550); 16 Jan 2020 21:58:17 -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 19835 invoked from network); 16 Jan 2020 21:58:16 -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=90kSKrsPpbCluN0U4RDiVNxyzvDrsXuzgr4VAEgKFuc=; b=VNVb2CG8c3HkjMqddLo98y3OPZa+WSPTAgoYdSf7FbWI5WNi3wnlLK0p32BzwbDJkl DxW3dVwqqXEzvQDJ/t2t8XVh7UcdBnxl57fQBAwB07GY+Kc5s2di8Ti7bcTy/S2/pe8U ishyY7KqIu0u9X9VZYcJD0ArT3LnkwpSs93Icdin/XOuAUh49RrudpoY+q52GTTYSx40 GpnMdqP6bRbODHeQRjbKNwwaXhmlW1mB68/yoKkEelegSKWRaD4DkiQa+ct5BY9CQ8b+ WhW5jUQJ1e+6OM3m0IRmGb8dXhOkx9FNog8QbWSOqQkVjep7R9pRuyilDTthUXsbS/HD LriA== 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=90kSKrsPpbCluN0U4RDiVNxyzvDrsXuzgr4VAEgKFuc=; b=WzsGcptnnp7rdsGshr83Hi9907lR2RMNa6/CorrSfhMXPP1YBNJz+OPTwE9y9BFroq T2+vfsWJIZM3iKaeF/c1gIJuh/wGGgn9qElVLa3ifZ9wIWSWqYaQYO0zOKUx8HoKjbob ArHRtN7rIx404fTQAIjepYYivU6OV6B5PlRAjYMzP27HfkILXj05zVaS7gYtRgM1fiCI 2aqHs6Bxk7bEyTTyrd0a+HQ5bJwj9dYdoZhB/ZqgYcuxz4BnGVRksJq6bBdQlo1/ugVl oBHLWhdVcqniQB9jegkbrtyDBbJstYYzhDpWf3eJFE704HwQzZRgCZbONZhpXXruW3a1 GaUw== X-Gm-Message-State: APjAAAUzO5phYJeasookRlvTwHeo1GlRtgrc2Y+FGrqcWKOM57LDoDAj Al1amaN27DQQJnt1/izK3rFGNKC0YGfsoEd7OyPsTw== X-Google-Smtp-Source: APXvYqzrUqH5/W2UZ+FeXG0hZr7Tack1J9k9eB9pBix6w41rOK+OkTqsOrnRDdc5aMPEGFoHQeXxcn/0tewoHbFlgSg= X-Received: by 2002:a67:ae43:: with SMTP id u3mr3413809vsh.44.1579211884786; Thu, 16 Jan 2020 13:58:04 -0800 (PST) MIME-Version: 1.0 References: <20191018161033.261971-1-samitolvanen@google.com> <20191206221351.38241-1-samitolvanen@google.com> <20191206221351.38241-15-samitolvanen@google.com> <20200116182414.GC22420@willie-the-truck> In-Reply-To: <20200116182414.GC22420@willie-the-truck> From: Sami Tolvanen Date: Thu, 16 Jan 2020 13:57:53 -0800 Message-ID: Subject: Re: [PATCH v6 14/15] arm64: implement Shadow Call Stack To: Will Deacon Cc: Catalin Marinas , Steven Rostedt , Masami Hiramatsu , Ard Biesheuvel , Mark Rutland , Dave Martin , Kees Cook , Laura Abbott , Marc Zyngier , 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, Jan 16, 2020 at 10:24 AM Will Deacon wrote: > > .macro irq_stack_entry > > mov x19, sp // preserve the original sp > > +#ifdef CONFIG_SHADOW_CALL_STACK > > + mov x20, x18 // preserve the original shadow stack > > +#endif > > Hmm, not sure about corrupting x20 here. Doesn't it hold the PMR value from > kernel_entry? You're right, and it's used in el1_irq after irq_handler if CONFIG_ARM64_PSEUDO_NMI is enabled. Thanks for pointing this out. Looks like one of x24-x29 should be safe here, and the comment needs to be updated to explain why x20-x23 shouldn't be corrupted. Sami