From patchwork Tue Feb 23 02:35:28 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jian Cai X-Patchwork-Id: 12099791 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=-26.2 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=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 85A75C433DB for ; Tue, 23 Feb 2021 02:36:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 55A3464E41 for ; Tue, 23 Feb 2021 02:36:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230099AbhBWCga (ORCPT ); Mon, 22 Feb 2021 21:36:30 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46042 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230415AbhBWCg1 (ORCPT ); Mon, 22 Feb 2021 21:36:27 -0500 Received: from mail-pf1-x449.google.com (mail-pf1-x449.google.com [IPv6:2607:f8b0:4864:20::449]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DBA4FC06178A for ; Mon, 22 Feb 2021 18:35:46 -0800 (PST) Received: by mail-pf1-x449.google.com with SMTP id 185so5688226pfx.5 for ; Mon, 22 Feb 2021 18:35:46 -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=PGrLnEq5sje+DbyVyjyk9DtPrIKTxkj/GFVaSNwb+20=; b=lQPJcLW5Zj/rVq/5KMZi6Bk5Gxp9bi/jqYNJj/hkmFM6gzte6FNZy8pUhQPuF48DW5 rgdLyFQsyQ6U4RJUQqukWwxkSjocc0fLx+yt1DM01Qk39F7C/1AXZh+zjBdJxQ/3G0By 9Q1STBNlBg5Q7c+WlQM3qRq5jdlJ/xEHfGwh+b+RySqJGyYgto60gGTcmqgVTnskcTia voGzzLmvFVyrWpAvMnajOE6rcF29MHLzcWao+b+LIqDC6xm2dNFZctXjqUO3V/BvFPkl xIDw2+GeuCSLwm+cSUCmzXDs9pW4C7jufUXw/nbxuMFcESLv2rHy/6q1Bho4udqCsDPz 0t3w== 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=PGrLnEq5sje+DbyVyjyk9DtPrIKTxkj/GFVaSNwb+20=; b=qjKN4jMEFXOH50yKN2sMt5FQ7TktuxMHW+GVgkKBfsK7nydjm3qMEpThZ0y6PamaWJ jbqsKZVfH78aHgezc3YJtxmV3XIQ1HZDJmgNgcyQm8Kh1lhinIlVazNBtIhPxbggxAKp o/jh2BBUnZMjtxsW/aBb9FcB6PzQ5nJbfzr3teI0iaRpcAiyxlhN85n1XTEsx8GOdkmv U+ZV3HSXkvAprU1cd9xfTSiJsiNGyz8HVfubM4FLqYAxei2oeCPaCBu8K86cMDamfqj7 y+sHDa9W58YesxLLLg4DpvLfIvSYvtahpuwn2HBagUv7/hOEOLpIOxmG3s3R3Hbmy247 TupA== X-Gm-Message-State: AOAM531Eb5WrFmtGTStG56rOMy1Lu45D7TRoeEVKmM71LMkAoQZ97SSN xyGTXh58i5aui95vFcnPwyCT93kEnEhy X-Google-Smtp-Source: ABdhPJwpIgoHP79+CAP1cZb8niAgyx2loeUCwl0+OoIAPkr358YzHC0nbYkhT6jM2oeR9Nm6NApKoYyBPvq+ Sender: "jiancai via sendgmr" X-Received: from jiancai.svl.corp.google.com ([2620:15c:2ce:0:7985:60cc:661a:9692]) (user=jiancai job=sendgmr) by 2002:a17:90a:8e83:: with SMTP id f3mr27877234pjo.70.1614047746241; Mon, 22 Feb 2021 18:35:46 -0800 (PST) Date: Mon, 22 Feb 2021 18:35:28 -0800 In-Reply-To: <20210223023125.2265845-1-jiancai@google.com> Message-Id: <20210223023542.2287529-1-jiancai@google.com> Mime-Version: 1.0 References: <20210223023125.2265845-1-jiancai@google.com> X-Mailer: git-send-email 2.30.0.617.g56c4b15f3c-goog Subject: [PATCH v5] 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 , Russell King , Catalin Marinas , James Morris , "Serge E. Hallyn" , Arnd Bergmann , Masahiro Yamada , Krzysztof Kozlowski , Marc Zyngier , Kees Cook , " =?utf-8?q?Andreas_F=C3=A4rber?= " , Ard Biesheuvel , Ingo Molnar , Andrew Morton , Mike Rapoport , Mark Rutland , David Brazdil , James Morse , 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 Suggested-by: Russell King Reviewed-by: Nathan Chancellor Signed-off-by: Jian Cai --- Changes v4->v5: Removed "default n" and made the description target indepdent in Kconfig.hardening. Please ignore my last email, it did not include the changes. 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 | 8 ++++++++ 6 files changed, 26 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..db76ad732c14 100644 --- a/security/Kconfig.hardening +++ b/security/Kconfig.hardening @@ -121,6 +121,14 @@ choice endchoice +config HARDEN_SLS_ALL + bool "enable SLS vulnerability hardening" + depends on $(cc-option,-mharden-sls=all) + help + Enables straight-line speculation vulnerability hardening. This inserts + speculation barrier instruction sequences after certain unconditional jumps + to prevent speculative execution past those barriers. + config GCC_PLUGIN_STRUCTLEAK_VERBOSE bool "Report forcefully initialized variables" depends on GCC_PLUGIN_STRUCTLEAK