From patchwork Fri Oct 18 16:10:15 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sami Tolvanen X-Patchwork-Id: 11199025 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 6CEDF17EE for ; Fri, 18 Oct 2019 16:10:56 +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 40DB1222BD for ; Fri, 18 Oct 2019 16:10:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="g+fSJL/t"; dkim=fail reason="signature verification failed" (2048-bit key) header.d=google.com header.i=@google.com header.b="qgbEQaGz" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 40DB1222BD 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+patchwork-linux-arm=patchwork.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:From:Subject:Mime-Version:Message-Id :Date:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=mTT+JiEqH5uyX5axuk8FDFPxGq4EUrGVA6BqrcAKZPQ=; b=g+fSJL/tdOKgGR IUXhEztZPv+Erv8eGJ7ArcKjkSvlu4NtW/OL1wdh/1/PHJHuBggwC7UZ+mg6pXLzek0Bn7F7+va42 ro8aZpHzdNh0KaEmBzHWtTn0KMp0cQeEqa1owHpB8J2XsMP1GSapA2rCZpvVgRplOoLGEpcbuU4LR kJMJU5pw7Sw8tXgoaign0bsW9ZB20EplFqV4hf27GCvuGhd8E5fPZX087nXCUnHTLtImUeMyFCYsy szl1pHEEQ4BggbJPBvgHLAtq6iJJPcuL1QUMaQhdPMftPMwZeUJU0jXOxtAQqGQFMrSigj+s+baCl SWF0SuUWK+OCoxza482Q==; 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 1iLUq2-0001Tj-Oi; Fri, 18 Oct 2019 16:10:50 +0000 Received: from mail-yw1-xc4a.google.com ([2607:f8b0:4864:20::c4a]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1iLUpz-0001Se-0j for linux-arm-kernel@lists.infradead.org; Fri, 18 Oct 2019 16:10:48 +0000 Received: by mail-yw1-xc4a.google.com with SMTP id y70so4764262ywd.8 for ; Fri, 18 Oct 2019 09:10:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:message-id:mime-version:subject:from:to:cc; bh=t+DRDqz67Twe6Iyofi8RQAeNodEvIc7fNPUNsIrBR+w=; b=qgbEQaGzHqaPH3cxTJE6CGTvZ+cRjHUHTkYr1B9DStapni7EFSvFnUDWSGPFTm7gwQ BQRlnzPOMPn4q93e238qrgFaMvCQf9Spzz7SINiIlVpuYks/Wu8Nwa1QmimiSJxpH3pA zXtHmrE7MTXaAB6BLpC8vL3pFXfn9A40pGj+qHFCNXTwD0ywpccoB55v3hYAWCkjkCgv t4a0qzeiaiVD3qeEEiRLETv6os7mi6JMjFcZQ7HZ3TsPYfuCCRN07OVVFEBv060hDwM0 Oe2+l3QRysVBZMWOYZ/v2Sou4QvuVNVoxWjAknk7l6ulOzhXQHgz5ej8/LwC2yX3JfcO auvQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc; bh=t+DRDqz67Twe6Iyofi8RQAeNodEvIc7fNPUNsIrBR+w=; b=BR8dc3tjF2qnzx6W6zK0KaFNEhLMsUPWVCF5Bu6TpilC/4eGy4SMksJ+SBVJ0qeSGR 4knn0BsYllA0mKM4MGPJQO4raDvVZykYWK6U6c40waOmgm1FJk2ZFnHxYFgHcQRTbsov H6V4pMBosRNHMpmsouQuld8q1tHoQ/zimrJ2RSuAJqWHyzD9CjUqtCD3cwXPCpC4jGZs 9JJ0pA0hlaqXJh2zJvSdvLLlWvLp48yadaQ2dQcfpnOF6J8Hw/NIuwXNmCCaAppNuQbK QKojYhY1V9dyN5Ft3OszaORHD/hDdDPDdT4VbO4D1r0g+09kG1LVUflW8PuHnkIowpyC 99lQ== X-Gm-Message-State: APjAAAVDxUobNsH8+5mpb88p3/L+OWgCi8Vrda4cNG8E3U2iNaYXfuvw 60bXW4++WDrZrnPlMZFzOrvuizXSEh00mYqfOM8= X-Google-Smtp-Source: APXvYqyvgW1/nPqoxtlaKdWfjDEG7KEXwdtGVI7DdMRD1tlwHR6z5N+W9oDyStEa7Ea2uqFWOqGCG100k3GuhoDibZE= X-Received: by 2002:a25:a324:: with SMTP id d33mr6752834ybi.58.1571415044349; Fri, 18 Oct 2019 09:10:44 -0700 (PDT) Date: Fri, 18 Oct 2019 09:10:15 -0700 Message-Id: <20191018161033.261971-1-samitolvanen@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.23.0.866.gb869b98d4c-goog Subject: [PATCH 00/18] add support for Clang's Shadow Call Stack From: Sami Tolvanen To: Will Deacon , Catalin Marinas , Steven Rostedt , Ard Biesheuvel X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191018_091047_090398_0CD19A4A X-CRM114-Status: GOOD ( 14.83 ) X-Spam-Score: -7.7 (-------) X-Spam-Report: SpamAssassin version 3.4.2 on bombadil.infradead.org summary: Content analysis details: (-7.7 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at https://www.dnswl.org/, no trust [2607:f8b0:4864:20:0:0:0:c4a listed in] [list.dnswl.org] -7.5 USER_IN_DEF_DKIM_WL From: address is in the default DKIM white-list 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.0 SPF_PASS SPF: sender matches SPF record -0.1 DKIM_VALID_EF Message has a valid DKIM or DK signature from envelope-from domain -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature -0.0 DKIMWL_WL_MED DKIMwl.org - Medium sender 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 , kernel-hardening@lists.openwall.com, Nick Desaulniers , linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com, Sami Tolvanen , Laura Abbott , Dave Martin , linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org This patch series adds support for Clang's Shadow Call Stack (SCS) mitigation, which uses a separately allocated shadow stack to protect against return address overwrites. More information can be found here: https://clang.llvm.org/docs/ShadowCallStack.html SCS is currently supported only on arm64, where the compiler requires the x18 register to be reserved for holding the current task's shadow stack pointer. Because of this, the series includes four patches from Ard to remove x18 usage from assembly code and to reserve the register from general allocation. With -fsanitize=shadow-call-stack, the compiler injects instructions to all non-leaf C functions to store the return address to the shadow stack and unconditionally load it again before returning. As a result, SCS is incompatible with features that rely on modifying function return addresses to alter control flow, such as function graph tracing and kretprobes. A copy of the return address is still kept in the kernel stack for compatibility with stack unwinding, for example. SCS has a minimal performance overhead, but allocating shadow stacks increases kernel memory usage. The feature is therefore mostly useful on hardware that lacks support for PAC instructions. This series adds a ROP protection choice to the kernel configuration, where other return address protection options can be selected as they are added to the kernel. Ard Biesheuvel (4): arm64/lib: copy_page: avoid x18 register in assembler code arm64: kvm: stop treating register x18 as caller save arm64: kernel: avoid x18 as an arbitrary temp register arm64: kbuild: reserve reg x18 from general allocation by the compiler Sami Tolvanen (14): arm64: mm: don't use x18 in idmap_kpti_install_ng_mappings add support for Clang's Shadow Call Stack (SCS) scs: add accounting scs: add support for stack usage debugging trace: disable function graph tracing with SCS kprobes: fix compilation without CONFIG_KRETPROBES kprobes: disable kretprobes with SCS arm64: reserve x18 only with Shadow Call Stack arm64: preserve x18 when CPU is suspended arm64: efi: restore x18 if it was corrupted arm64: vdso: disable Shadow Call Stack arm64: kprobes: fix kprobes without CONFIG_KRETPROBES arm64: disable SCS for hypervisor code arm64: implement Shadow Call Stack Makefile | 6 + arch/Kconfig | 41 ++++- arch/arm64/Kconfig | 1 + arch/arm64/Makefile | 4 + arch/arm64/include/asm/scs.h | 60 ++++++++ arch/arm64/include/asm/stacktrace.h | 4 + arch/arm64/include/asm/thread_info.h | 3 + arch/arm64/kernel/Makefile | 1 + arch/arm64/kernel/asm-offsets.c | 3 + arch/arm64/kernel/cpu-reset.S | 4 +- arch/arm64/kernel/efi-rt-wrapper.S | 7 +- arch/arm64/kernel/entry.S | 23 +++ arch/arm64/kernel/head.S | 9 ++ arch/arm64/kernel/irq.c | 2 + arch/arm64/kernel/probes/kprobes.c | 2 + arch/arm64/kernel/process.c | 3 + arch/arm64/kernel/scs.c | 39 +++++ arch/arm64/kernel/smp.c | 4 + arch/arm64/kernel/vdso/Makefile | 2 +- arch/arm64/kvm/hyp/Makefile | 3 +- arch/arm64/kvm/hyp/entry.S | 12 +- arch/arm64/lib/copy_page.S | 38 ++--- arch/arm64/mm/proc.S | 69 +++++---- drivers/base/node.c | 6 + fs/proc/meminfo.c | 4 + include/linux/compiler-clang.h | 2 + include/linux/compiler_types.h | 4 + include/linux/mmzone.h | 3 + include/linux/scs.h | 88 +++++++++++ init/init_task.c | 6 + init/main.c | 3 + kernel/Makefile | 1 + kernel/fork.c | 9 ++ kernel/kprobes.c | 38 ++--- kernel/sched/core.c | 2 + kernel/sched/sched.h | 1 + kernel/scs.c | 221 +++++++++++++++++++++++++++ kernel/trace/Kconfig | 1 + mm/page_alloc.c | 6 + mm/vmstat.c | 3 + 40 files changed, 656 insertions(+), 82 deletions(-) create mode 100644 arch/arm64/include/asm/scs.h create mode 100644 arch/arm64/kernel/scs.c create mode 100644 include/linux/scs.h create mode 100644 kernel/scs.c