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=-20.4 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 5532FC63697 for ; Fri, 13 Nov 2020 22:17:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1CC0422252 for ; Fri, 13 Nov 2020 22:17:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="AitFtvjP" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726532AbgKMWRX (ORCPT ); Fri, 13 Nov 2020 17:17:23 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48504 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726485AbgKMWRN (ORCPT ); Fri, 13 Nov 2020 17:17:13 -0500 Received: from mail-wr1-x44a.google.com (mail-wr1-x44a.google.com [IPv6:2a00:1450:4864:20::44a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 167A5C0613D1 for ; Fri, 13 Nov 2020 14:17:12 -0800 (PST) Received: by mail-wr1-x44a.google.com with SMTP id z13so4678869wrm.19 for ; Fri, 13 Nov 2020 14:17:12 -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:to:cc; bh=4rzWjrKiYZNXmMUdZmlcBaQ0UpVVJfESdD9t64fiN78=; b=AitFtvjP3XP8OIRSBxQDs/NAqQDBtJQaWtJoA9DS5QLGpmaaHG32m6dlLaEKINVxJp 5pJldf65R+zFngI0Kqm169fA2A1+oKzDVHFcyW9VlKR9LEyE1d9E9NAJ0yxCtXLOtBzz kvpvnlQ3l4j1al6Xxgal46wd26mMkDOXGBWmIp5b6O4w03IvW2+hZnEYZfUJQk/3P601 M0sp+HCSlPkMmJJXYHTkyV1wcQFJ+X1Zt4edrWrTvcxmw9/IWL/zaFEWjYsrafkApbGe xyoaPnY656jmvt59NgEUOJmRcZO0gmFx8L/Y2/w6NqsJ12altaSH/1mOyd6F19MklRLY REAg== 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:to:cc; bh=4rzWjrKiYZNXmMUdZmlcBaQ0UpVVJfESdD9t64fiN78=; b=T5FGbGrudagYhQAkTEP7fVqwi7Of8WfD9WTnbv0yNCGAYNytG7LaAo3ohdcsDwEMel nThG/j/0V4RP5xGTeSm4aXEzEJaJtiZb2jt40S1ON52Myj/YCTAaSvPUJ0RD/lC/VCeu Xpe9kmqYEYqwyyoNTUQz2HwhMmjfyr7uPfIklSi6rUOV/+DUy00MTgCqnyK1v3b9OEM5 4LVKPCJVQu0hFgUb5PNnHE5qpUs5h6CWJtLso4XvmToNbn5YTEqo/rLRNExSBq7VtUbJ KNnq03a/B5cnDvhKuTJd8vavJpp/aSTmBhCtACK+8hYdG+S37ZW8VNdcS3MrD6q/wXDq wIJw== X-Gm-Message-State: AOAM533wwkhUGVRklN9LUog0gkaZL4aXX9aPc6cHQsAjXA/refD2Qk5a Dq2PS5iDMFRAYc8kxG1QMZwLj3NnHUZwS2zj X-Google-Smtp-Source: ABdhPJz8WZKtECKchZne+Sare5vhhbO4oHuDvYlev3gyAUzkeNTz2ollOH9J6qgiMpFPl2bei18ZH+2I9K6bSR4j Sender: "andreyknvl via sendgmr" X-Received: from andreyknvl3.muc.corp.google.com ([2a00:79e0:15:13:7220:84ff:fe09:7e9d]) (user=andreyknvl job=sendgmr) by 2002:a1c:964d:: with SMTP id y74mr4390904wmd.129.1605305830806; Fri, 13 Nov 2020 14:17:10 -0800 (PST) Date: Fri, 13 Nov 2020 23:15:51 +0100 In-Reply-To: Message-Id: Mime-Version: 1.0 References: X-Mailer: git-send-email 2.29.2.299.gdc1121823c-goog Subject: [PATCH mm v10 23/42] kasan: introduce CONFIG_KASAN_HW_TAGS From: Andrey Konovalov To: Andrew Morton Cc: Catalin Marinas , Will Deacon , Vincenzo Frascino , Dmitry Vyukov , Andrey Ryabinin , Alexander Potapenko , Marco Elver , Evgenii Stepanov , Branislav Rankov , Kevin Brodsky , kasan-dev@googlegroups.com, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrey Konovalov Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This patch adds a configuration option for a new KASAN mode called hardware tag-based KASAN. This mode uses the memory tagging approach like the software tag-based mode, but relies on arm64 Memory Tagging Extension feature for tag management and access checking. Signed-off-by: Andrey Konovalov Co-developed-by: Vincenzo Frascino Signed-off-by: Vincenzo Frascino Reviewed-by: Marco Elver --- Change-Id: I246c2def9fffa6563278db1bddfbe742ca7bdefe --- lib/Kconfig.kasan | 61 ++++++++++++++++++++++++++++++++++------------- 1 file changed, 44 insertions(+), 17 deletions(-) diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan index c0e9e7874122..f5fa4ba126bf 100644 --- a/lib/Kconfig.kasan +++ b/lib/Kconfig.kasan @@ -6,7 +6,10 @@ config HAVE_ARCH_KASAN config HAVE_ARCH_KASAN_SW_TAGS bool -config HAVE_ARCH_KASAN_VMALLOC +config HAVE_ARCH_KASAN_HW_TAGS + bool + +config HAVE_ARCH_KASAN_VMALLOC bool config CC_HAS_KASAN_GENERIC @@ -15,16 +18,19 @@ config CC_HAS_KASAN_GENERIC config CC_HAS_KASAN_SW_TAGS def_bool $(cc-option, -fsanitize=kernel-hwaddress) +# This option is only required for software KASAN modes. +# Old GCC versions don't have proper support for no_sanitize_address. +# See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89124 for details. config CC_HAS_WORKING_NOSANITIZE_ADDRESS def_bool !CC_IS_GCC || GCC_VERSION >= 80300 menuconfig KASAN bool "KASAN: runtime memory debugger" - depends on (HAVE_ARCH_KASAN && CC_HAS_KASAN_GENERIC) || \ - (HAVE_ARCH_KASAN_SW_TAGS && CC_HAS_KASAN_SW_TAGS) + depends on (((HAVE_ARCH_KASAN && CC_HAS_KASAN_GENERIC) || \ + (HAVE_ARCH_KASAN_SW_TAGS && CC_HAS_KASAN_SW_TAGS)) && \ + CC_HAS_WORKING_NOSANITIZE_ADDRESS) || \ + HAVE_ARCH_KASAN_HW_TAGS depends on (SLUB && SYSFS) || (SLAB && !DEBUG_SLAB) - depends on CC_HAS_WORKING_NOSANITIZE_ADDRESS - select CONSTRUCTORS select STACKDEPOT help Enables KASAN (KernelAddressSANitizer) - runtime memory debugger, @@ -37,18 +43,24 @@ choice prompt "KASAN mode" default KASAN_GENERIC help - KASAN has two modes: generic KASAN (similar to userspace ASan, - x86_64/arm64/xtensa, enabled with CONFIG_KASAN_GENERIC) and - software tag-based KASAN (a version based on software memory - tagging, arm64 only, similar to userspace HWASan, enabled with - CONFIG_KASAN_SW_TAGS). + KASAN has three modes: + 1. generic KASAN (similar to userspace ASan, + x86_64/arm64/xtensa, enabled with CONFIG_KASAN_GENERIC), + 2. software tag-based KASAN (arm64 only, based on software + memory tagging (similar to userspace HWASan), enabled with + CONFIG_KASAN_SW_TAGS), and + 3. hardware tag-based KASAN (arm64 only, based on hardware + memory tagging, enabled with CONFIG_KASAN_HW_TAGS). + + All KASAN modes are strictly debugging features. - Both generic and tag-based KASAN are strictly debugging features. + For better error reports enable CONFIG_STACKTRACE. config KASAN_GENERIC bool "Generic mode" depends on HAVE_ARCH_KASAN && CC_HAS_KASAN_GENERIC select SLUB_DEBUG if SLUB + select CONSTRUCTORS help Enables generic KASAN mode. @@ -61,8 +73,6 @@ config KASAN_GENERIC and introduces an overhead of ~x1.5 for the rest of the allocations. The performance slowdown is ~x3. - For better error detection enable CONFIG_STACKTRACE. - Currently CONFIG_KASAN_GENERIC doesn't work with CONFIG_DEBUG_SLAB (the resulting kernel does not boot). @@ -70,11 +80,15 @@ config KASAN_SW_TAGS bool "Software tag-based mode" depends on HAVE_ARCH_KASAN_SW_TAGS && CC_HAS_KASAN_SW_TAGS select SLUB_DEBUG if SLUB + select CONSTRUCTORS help Enables software tag-based KASAN mode. - This mode requires Top Byte Ignore support by the CPU and therefore - is only supported for arm64. This mode requires Clang. + This mode require software memory tagging support in the form of + HWASan-like compiler instrumentation. + + Currently this mode is only implemented for arm64 CPUs and relies on + Top Byte Ignore. This mode requires Clang. This mode consumes about 1/16th of available memory at kernel start and introduces an overhead of ~20% for the rest of the allocations. @@ -82,15 +96,27 @@ config KASAN_SW_TAGS casting and comparison, as it embeds tags into the top byte of each pointer. - For better error detection enable CONFIG_STACKTRACE. - Currently CONFIG_KASAN_SW_TAGS doesn't work with CONFIG_DEBUG_SLAB (the resulting kernel does not boot). +config KASAN_HW_TAGS + bool "Hardware tag-based mode" + depends on HAVE_ARCH_KASAN_HW_TAGS + depends on SLUB + help + Enables hardware tag-based KASAN mode. + + This mode requires hardware memory tagging support, and can be used + by any architecture that provides it. + + Currently this mode is only implemented for arm64 CPUs starting from + ARMv8.5 and relies on Memory Tagging Extension and Top Byte Ignore. + endchoice choice prompt "Instrumentation type" + depends on KASAN_GENERIC || KASAN_SW_TAGS default KASAN_OUTLINE config KASAN_OUTLINE @@ -114,6 +140,7 @@ endchoice config KASAN_STACK_ENABLE bool "Enable stack instrumentation (unsafe)" if CC_IS_CLANG && !COMPILE_TEST + depends on KASAN_GENERIC || KASAN_SW_TAGS help The LLVM stack address sanitizer has a know problem that causes excessive stack usage in a lot of functions, see -- 2.29.2.299.gdc1121823c-goog