From patchwork Fri Feb 19 20:18:40 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jian Cai X-Patchwork-Id: 12096093 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=-26.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=unavailable 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 00E67C433E0 for ; Fri, 19 Feb 2021 20:19:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B3E1C64EB8 for ; Fri, 19 Feb 2021 20:19:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229755AbhBSUTh (ORCPT ); Fri, 19 Feb 2021 15:19:37 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33546 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229515AbhBSUTg (ORCPT ); Fri, 19 Feb 2021 15:19:36 -0500 Received: from mail-qk1-x74a.google.com (mail-qk1-x74a.google.com [IPv6:2607:f8b0:4864:20::74a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9CC07C061574 for ; Fri, 19 Feb 2021 12:18:56 -0800 (PST) Received: by mail-qk1-x74a.google.com with SMTP id i11so4300844qkn.21 for ; Fri, 19 Feb 2021 12:18:56 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:date:in-reply-to:message-id:mime-version:references:subject :from:cc; bh=7T2c0bl5OkkQ79Gbe1n87t+HukBdE3TTJ/DXUdpKX6g=; b=jI/PzXCkzv+CnZNka4GAons5+7izWtdVJUd+7qRf/m+dBDEUQdqf+vMddpUjj4dwHs N9dic8hCJtSz+MZJC6XOC1kkah28rIKnZmCGgRyUnG9oA9ih/2fwsir8aSSQfcvEPO0x zwynFaX2a8v52FYb3xnXRSXcWOIPbdhYl0TGczuGrbp1GIpgPGLGQSIEz6644YnnFpAU UMUXHBEBQYpnD34bcFGV1LhJCFIRRQt5HXzRXmS6ljiS9ECQcUH2jFDrzKv+21/GdYyO MI2GSCSVjZ081U9R2E5xpMW/4XFbpy6sTk46xgHEw5Zv2x2kUoiwsgK2a6r3GbylJCWu IhHA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:in-reply-to:message-id:mime-version :references:subject:from:cc; bh=7T2c0bl5OkkQ79Gbe1n87t+HukBdE3TTJ/DXUdpKX6g=; b=NPHxsL7ZKhudnSsV+89fm41n1WO8ZrraMQsYnN647cHm0Y+alpobdV/TF7yEP1epzE ymReHjXecmuFauaSgUJTym0Ql86ACifjUOx76gaB8/MBTm5Cnr6b7GgWEEUOw5VAa+G1 bOWmKDQaZXYd9d//V+u8299BEL/PiLPqU45Qqc+CNy4TZ6f4ZNYnOfLbWpN/2WwIjerA iei/Ov+LJiFcCx/H75JHePOnGkXwZmBWazaCIHab+W3f6KKqVdA8CKZ9yJhlsDsFD4j9 BC+i3ZgygXXyX+0Iyb5YGmsgLnkn0M2tryZ4pSRm9hZPLMzxs03jhqbi8lZCJzizuyFk eKWQ== X-Gm-Message-State: AOAM532ek2gEDWEVrUesfG31FQSzwa/dxrBJpC4z/vdRd/6EP5fuOUtm 0aatiC0ksYBwUUDLO/hs02pnS2iiFxD5 X-Google-Smtp-Source: ABdhPJwMSp/rAEOX2pa/XWlA4huWXhXIwFC1NziSv58q8T8Af4FW8ptK4uG0CBbmUC48wraFdMIWN6oOpPNq Sender: "jiancai via sendgmr" X-Received: from jiancai.svl.corp.google.com ([2620:15c:2ce:0:6578:8d7f:50d0:55c8]) (user=jiancai job=sendgmr) by 2002:a0c:c488:: with SMTP id u8mr3180406qvi.9.1613765935591; Fri, 19 Feb 2021 12:18:55 -0800 (PST) Date: Fri, 19 Feb 2021 12:18:40 -0800 In-Reply-To: <20210212195255.1321544-1-jiancai@google.com> Message-Id: <20210219201852.3213914-1-jiancai@google.com> Mime-Version: 1.0 References: <20210212195255.1321544-1-jiancai@google.com> X-Mailer: git-send-email 2.30.0.617.g56c4b15f3c-goog Subject: [PATCH v3] ARM: Implement SLS mitigation From: Jian Cai Cc: ndesaulniers@google.com, manojgupta@google.com, llozano@google.com, clang-built-linux@googlegroups.com, Jian Cai , Nathan Chancellor , David Laight , Will Deacon , Russell King , Catalin Marinas , James Morris , "Serge E. Hallyn" , Arnd Bergmann , Masahiro Yamada , Kees Cook , Ard Biesheuvel , " =?utf-8?q?Andreas_F=C3=A4rber?= " , Ingo Molnar , Olof Johansson , Marc Zyngier , Andrew Morton , Mike Rapoport , David Brazdil , James Morse , Mark Rutland , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org To: unlisted-recipients:; (no To-header on input) Precedence: bulk List-ID: This patch adds CONFIG_HARDEN_SLS_ALL that can be used to turn on -mharden-sls=all, which mitigates the straight-line speculation vulnerability, speculative execution of the instruction following some unconditional jumps. Notice -mharden-sls= has other options as below, and this config turns on the strongest option. all: enable all mitigations against Straight Line Speculation that are implemented. none: disable all mitigations against Straight Line Speculation. retbr: enable the mitigation against Straight Line Speculation for RET and BR instructions. blr: enable the mitigation against Straight Line Speculation for BLR instructions. Links: https://reviews.llvm.org/D93221 https://reviews.llvm.org/D81404 https://developer.arm.com/support/arm-security-updates/speculative-processor-vulnerability/downloads/straight-line-speculation https://developer.arm.com/support/arm-security-updates/speculative-processor-vulnerability/frequently-asked-questions#SLS2 Suggested-by: Manoj Gupta Suggested-by: Nick Desaulniers Suggested-by: Nathan Chancellor Suggested-by: David Laight Suggested-by: Will Deacon Reviewed-by: Nathan Chancellor Signed-off-by: Jian Cai --- Changes v2 -> v3: Modify linker scripts as Nick suggested to address boot failure (verified with qemu). Added more details in Kconfig.hardening description. Disable the config by default. arch/arm/Makefile | 4 ++++ arch/arm/include/asm/vmlinux.lds.h | 4 ++++ arch/arm/kernel/vmlinux.lds.S | 1 + arch/arm64/Makefile | 4 ++++ arch/arm64/kernel/vmlinux.lds.S | 5 +++++ security/Kconfig.hardening | 10 ++++++++++ 6 files changed, 28 insertions(+) diff --git a/arch/arm/Makefile b/arch/arm/Makefile index 4aaec9599e8a..11d89ef32da9 100644 --- a/arch/arm/Makefile +++ b/arch/arm/Makefile @@ -48,6 +48,10 @@ CHECKFLAGS += -D__ARMEL__ KBUILD_LDFLAGS += -EL endif +ifeq ($(CONFIG_HARDEN_SLS_ALL), y) +KBUILD_CFLAGS += -mharden-sls=all +endif + # # The Scalar Replacement of Aggregates (SRA) optimization pass in GCC 4.9 and # later may result in code being generated that handles signed short and signed diff --git a/arch/arm/include/asm/vmlinux.lds.h b/arch/arm/include/asm/vmlinux.lds.h index 4a91428c324d..c7f9717511ca 100644 --- a/arch/arm/include/asm/vmlinux.lds.h +++ b/arch/arm/include/asm/vmlinux.lds.h @@ -145,3 +145,7 @@ __edtcm_data = .; \ } \ . = __dtcm_start + SIZEOF(.data_dtcm); + +#define SLS_TEXT \ + ALIGN_FUNCTION(); \ + *(.text.__llvm_slsblr_thunk_*) diff --git a/arch/arm/kernel/vmlinux.lds.S b/arch/arm/kernel/vmlinux.lds.S index f7f4620d59c3..e71f2bc97bae 100644 --- a/arch/arm/kernel/vmlinux.lds.S +++ b/arch/arm/kernel/vmlinux.lds.S @@ -63,6 +63,7 @@ SECTIONS .text : { /* Real text segment */ _stext = .; /* Text and read-only data */ ARM_TEXT + SLS_TEXT } #ifdef CONFIG_DEBUG_ALIGN_RODATA diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile index 90309208bb28..ca7299b356a9 100644 --- a/arch/arm64/Makefile +++ b/arch/arm64/Makefile @@ -34,6 +34,10 @@ $(warning LSE atomics not supported by binutils) endif endif +ifeq ($(CONFIG_HARDEN_SLS_ALL), y) +KBUILD_CFLAGS += -mharden-sls=all +endif + cc_has_k_constraint := $(call try-run,echo \ 'int main(void) { \ asm volatile("and w0, w0, %w0" :: "K" (4294967295)); \ diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S index 4c0b0c89ad59..f8912e42ffcd 100644 --- a/arch/arm64/kernel/vmlinux.lds.S +++ b/arch/arm64/kernel/vmlinux.lds.S @@ -93,6 +93,10 @@ jiffies = jiffies_64; #define TRAMP_TEXT #endif +#define SLS_TEXT \ + ALIGN_FUNCTION(); \ + *(.text.__llvm_slsblr_thunk_*) + /* * The size of the PE/COFF section that covers the kernel image, which * runs from _stext to _edata, must be a round multiple of the PE/COFF @@ -144,6 +148,7 @@ SECTIONS HIBERNATE_TEXT TRAMP_TEXT *(.fixup) + SLS_TEXT *(.gnu.warning) . = ALIGN(16); *(.got) /* Global offset table */ diff --git a/security/Kconfig.hardening b/security/Kconfig.hardening index 269967c4fc1b..e70f227019e1 100644 --- a/security/Kconfig.hardening +++ b/security/Kconfig.hardening @@ -121,6 +121,16 @@ choice endchoice +config HARDEN_SLS_ALL + bool "enable SLS vulnerability hardening" + default n + def_bool $(cc-option,-mharden-sls=all) + help + Enables straight-line speculation vulnerability hardening on ARM and ARM64 + architectures. It inserts speculation barrier sequences (SB or DSB+ISB + depending on the target architecture) after RET and BR, and replacing + BLR with BL+BR sequence. + config GCC_PLUGIN_STRUCTLEAK_VERBOSE bool "Report forcefully initialized variables" depends on GCC_PLUGIN_STRUCTLEAK