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=-10.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 304D9C2D0E4 for ; Tue, 24 Nov 2020 22:04:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C03F3205ED for ; Tue, 24 Nov 2020 22:04:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="mMLjin9x" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388875AbgKXWEJ (ORCPT ); Tue, 24 Nov 2020 17:04:09 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57492 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731800AbgKXWEI (ORCPT ); Tue, 24 Nov 2020 17:04:08 -0500 Received: from mail-pl1-x643.google.com (mail-pl1-x643.google.com [IPv6:2607:f8b0:4864:20::643]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 936A9C0613D6 for ; Tue, 24 Nov 2020 14:04:07 -0800 (PST) Received: by mail-pl1-x643.google.com with SMTP id 18so11383502pli.13 for ; Tue, 24 Nov 2020 14:04:07 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=mprkldjb7CjnHozwqyjj+Jl9qcuDOi72QFxjdMqMlao=; b=mMLjin9xvm7UjvLFOvfEmfJpDOC7c85RswKHc8n121a3BqSZ429co2QEMkq09h7PGD /pnHcRwf9Yq7g07bYgg2AV8/2vndniTYuQlEM0X0PKI6Yfy3FvpLfdwPZSS7j/jxp4vd LOeKHavDBHSg6VuZ+W191jH1sHCsHkaBVq9IA= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=mprkldjb7CjnHozwqyjj+Jl9qcuDOi72QFxjdMqMlao=; b=LyJHlFX1V2AiQR1smeK4Khb4s/2myUSDqYRQU/JLEc4Gk5Bgyctlpkiwi4CaGJTAM3 cTOGTfxrKF88G7m+abGOc4Mua6y9Mg8N/ldizR6M4FIdPGUDkIHUGLd9y3dPCgBLxLEl wroC9xAmoj6nlU1gQiGAmL+8p91kRmOQ3/hnrpSxblNaqzEeG40WjsX+PbMeRsLJjV2A eLBPAB0Xrr4ykqBhFFcPvi6Ni3emRfcQeaqniIHOXcuTq37v9gSXp+8HqaBWy/Y1vJrb wZXTyUSPPOMMqUI7uViiEnutTt5Z7mb57mFWyzJLUmWp/stqLqJxvSo/mF6Hl1MBSowO UKow== X-Gm-Message-State: AOAM532Wa5iuTTvx7oNlUwBGTiYDlHBuC440pVVzxBTMM/MsMpJaiRpE CAFubCSTfJEAWSM62xFMCjhbIg== X-Google-Smtp-Source: ABdhPJwWsNzP3VcgbsHBRHePZyiD5EvmfBK/FQikTLooHtKWBj3ykTgPDCTI0MdKcQzupXKJ75E4ZQ== X-Received: by 2002:a17:902:bc46:b029:d6:d98a:1a68 with SMTP id t6-20020a170902bc46b02900d6d98a1a68mr276371plz.63.1606255447027; Tue, 24 Nov 2020 14:04:07 -0800 (PST) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id ne22sm184262pjb.45.2020.11.24.14.04.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 24 Nov 2020 14:04:06 -0800 (PST) Date: Tue, 24 Nov 2020 14:04:05 -0800 From: Kees Cook To: Sami Tolvanen Cc: Will Deacon , Catalin Marinas , Mark Rutland , James Morse , Ard Biesheuvel , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 1/2] scs: switch to vmapped shadow stacks Message-ID: <202011241404.9EA7F5F@keescook> References: <20201124195940.27061-1-samitolvanen@google.com> <20201124195940.27061-2-samitolvanen@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201124195940.27061-2-samitolvanen@google.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Nov 24, 2020 at 11:59:39AM -0800, Sami Tolvanen wrote: > The kernel currently uses kmem_cache to allocate shadow call stacks, > which means an overflows may not be immediately detected and can > potentially result in another task's shadow stack to be overwritten. > > This change switches SCS to use virtually mapped shadow stacks for > tasks, which increases shadow stack size to a full page and provides > more robust overflow detection, similarly to VMAP_STACK. > > Signed-off-by: Sami Tolvanen Reviewed-by: Kees Cook -- Kees Cook