From patchwork Wed Mar 31 20:54:52 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 12176277 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=-13.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 0D011C433B4 for ; Wed, 31 Mar 2021 20:55:31 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id 4C26661073 for ; Wed, 31 Mar 2021 20:55:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4C26661073 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=chromium.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernel-hardening-return-21099-kernel-hardening=archiver.kernel.org@lists.openwall.com Received: (qmail 11295 invoked by uid 550); 31 Mar 2021 20:55:16 -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 10237 invoked from network); 31 Mar 2021 20:55:15 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=8bZ3bzKOfhPGnPGG60VssYCADe64CpCvkm0duGoaMAA=; b=iK6Dd1WzfTgZlYmEbgnA8JsN6ev91O3XgM9qgKS6kJCpEDzjxzvzwCL7RPAIIEpMPO m6g+Zrkan6Wwii54JTWoNBmrYZfJ1o2xcdda5yUzNDrzCoTAdDL5oMoveSYaiu0rppz9 QW6uvmXPJPJYn+Oeme3ufD9LvkkfwQLu9XavI= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=8bZ3bzKOfhPGnPGG60VssYCADe64CpCvkm0duGoaMAA=; b=TsWTWmPOXSdYEWITQIiHwCAN0xVEMF8kiz9ev69IV0U87FU6KANzc8R1RuOX6Si2m4 XSr10O85lKur6yP1c8MqTgbIDt+VVjjohYaFFvh9j/hRj6+JK9a0T8ozly/csuIpaZbJ dk2cEHFRKIV65ytza6RNv7USBES40tqbTzlNQCyK/+zcdw46GFJL7tr+RBG5j2IwaQfh Z6Uc9MRZ+y+dJBmU0+8dc4Dy/GKvAuhfaCw8Pd8TALR8eJhhYl16Zc8YAVzg1JIN7sHQ H0vYf2a35fFMhL4D/y35HGnSJFqHLupKr6kmwY4eae/rELxnuuwIUO5MgKTmbQ5gApVR 6T4A== X-Gm-Message-State: AOAM531N3H4x3jBIGTrPc3C2ZrS6VZasGfJmK4R03enRRTkClc8je8Xa upVkjPiARu31aMnyvhwV2ksSDg== X-Google-Smtp-Source: ABdhPJzUF8uhkl0raN0ODpiCdyJAh9H7iGlPFlGsUGF89srEBkCnpo3FL1QwTdlnzj6Suocxnxa0yg== X-Received: by 2002:a63:af51:: with SMTP id s17mr4640944pgo.405.1617224103801; Wed, 31 Mar 2021 13:55:03 -0700 (PDT) From: Kees Cook To: Will Deacon Cc: Kees Cook , Catalin Marinas , Mark Rutland , Thomas Gleixner , Elena Reshetova , x86@kernel.org, Andy Lutomirski , Peter Zijlstra , Alexander Potapenko , Alexander Popov , Ard Biesheuvel , Jann Horn , Vlastimil Babka , David Hildenbrand , Mike Rapoport , Andrew Morton , Jonathan Corbet , Randy Dunlap , kernel-hardening@lists.openwall.com, linux-hardening@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH v9 0/6] Optionally randomize kernel stack offset each syscall Date: Wed, 31 Mar 2021 13:54:52 -0700 Message-Id: <20210331205458.1871746-1-keescook@chromium.org> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Hi Will (and Mark and Catalin), Can you take this via the arm64 tree for v5.13 please? Thomas has added his Reviewed-by, so it only leaves arm64's. :) v9: - comment position nit (tglx) - Added tglx's Reviewed-by v8: https://lore.kernel.org/lkml/20210330205750.428816-1-keescook@chromium.org/ v7: https://lore.kernel.org/lkml/20210319212835.3928492-1-keescook@chromium.org/ v6: https://lore.kernel.org/lkml/20210315180229.1224655-1-keescook@chromium.org/ v5: https://lore.kernel.org/lkml/20210309214301.678739-1-keescook@chromium.org/ v4: https://lore.kernel.org/lkml/20200622193146.2985288-1-keescook@chromium.org/ v3: https://lore.kernel.org/lkml/20200406231606.37619-1-keescook@chromium.org/ v2: https://lore.kernel.org/lkml/20200324203231.64324-1-keescook@chromium.org/ rfc: https://lore.kernel.org/kernel-hardening/20190329081358.30497-1-elena.reshetova@intel.com/ This is a continuation and refactoring of Elena's earlier effort to add kernel stack base offset randomization. In the time since the earlier discussions, two attacks[1][2] were made public that depended on stack determinism, so we're no longer in the position of "this is a good idea but we have no examples of attacks". :) Earlier discussions also devolved into debates on entropy sources, which is mostly a red herring, given the already low entropy available due to stack size. Regardless, entropy can be changed/improved separately from this series as needed. Earlier discussions also got stuck debating how much syscall overhead was too much, but this is also a red herring since the feature itself needs to be selectable at boot with no cost for those that don't want it: this is solved here with static branches. So, here is the latest improved version, made as arch-agnostic as possible, with usage added for x86 and arm64. It also includes some small static branch clean ups, and addresses some surprise performance issues due to the stack canary[3]. Thanks! -Kees [1] https://a13xp0p0v.github.io/2020/02/15/CVE-2019-18683.html [2] https://repositorio-aberto.up.pt/bitstream/10216/125357/2/374717.pdf [3] https://lore.kernel.org/lkml/202003281520.A9BFF461@keescook/ Kees Cook (6): jump_label: Provide CONFIG-driven build state defaults init_on_alloc: Optimize static branches stack: Optionally randomize kernel stack offset each syscall x86/entry: Enable random_kstack_offset support arm64: entry: Enable random_kstack_offset support lkdtm: Add REPORT_STACK for checking stack offsets .../admin-guide/kernel-parameters.txt | 11 ++++ Makefile | 4 ++ arch/Kconfig | 23 ++++++++ arch/arm64/Kconfig | 1 + arch/arm64/kernel/Makefile | 5 ++ arch/arm64/kernel/syscall.c | 16 ++++++ arch/x86/Kconfig | 1 + arch/x86/entry/common.c | 3 ++ arch/x86/include/asm/entry-common.h | 16 ++++++ drivers/misc/lkdtm/bugs.c | 17 ++++++ drivers/misc/lkdtm/core.c | 1 + drivers/misc/lkdtm/lkdtm.h | 1 + include/linux/jump_label.h | 19 +++++++ include/linux/mm.h | 10 ++-- include/linux/randomize_kstack.h | 54 +++++++++++++++++++ init/main.c | 23 ++++++++ mm/page_alloc.c | 4 +- mm/slab.h | 6 ++- 18 files changed, 207 insertions(+), 8 deletions(-) create mode 100644 include/linux/randomize_kstack.h