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=-15.8 required=3.0 tests=BAYES_00,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 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 2746BC0018C for ; Wed, 16 Dec 2020 04:47:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F42192333E for ; Wed, 16 Dec 2020 04:47:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725976AbgLPErV (ORCPT ); Tue, 15 Dec 2020 23:47:21 -0500 Received: from mail.kernel.org ([198.145.29.99]:52446 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725889AbgLPErV (ORCPT ); Tue, 15 Dec 2020 23:47:21 -0500 Date: Tue, 15 Dec 2020 20:46:39 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1608094000; bh=rLoI2A3ELodc0LPoTdnMsANDrVqT0FbHfRSmYRSSfNE=; h=From:To:Subject:In-Reply-To:From; b=hPOWH1LHY4Oo1+1Wjevv3Pbmi/LBIHatdUqruSbBBdeTiHIV0AUQDPDnnTy+HqPAM JMf3/LHOww9s6k7z+YTl2JUUEi8YfoVpLwH3McnSZjb08w3K2hjpo8vhn1H0I9QbS3 bP7uzZUa8Jcj8pxtR6rGxQzBarET6vG+u1YgrjWc= From: Andrew Morton To: akpm@linux-foundation.org, ardb@kernel.org, arnd@arndb.de, aryabinin@virtuozzo.com, dvyukov@google.com, elver@google.com, georgepope@android.com, herbert@gondor.apana.org.au, keescook@chromium.org, linux-mm@kvack.org, masahiroy@kernel.org, michal.lkml@markovi.net, mm-commits@vger.kernel.org, natechancellor@gmail.com, ndesaulniers@google.com, oberpar@linux.ibm.com, rdunlap@infradead.org, torvalds@linux-foundation.org Subject: [patch 79/95] ubsan: remove UBSAN_MISC in favor of individual options Message-ID: <20201216044639.-BpWNfx1s%akpm@linux-foundation.org> In-Reply-To: <20201215204156.f05ec694b907845bcfab5c44@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org From: Kees Cook Subject: ubsan: remove UBSAN_MISC in favor of individual options Make each UBSAN option individually selectable and remove UBSAN_MISC which no longer has any purpose. Add help text for each Kconfig, and include a reference to the Clang sanitizer documentation. Disable unsigned overflow by default (not available with GCC and makes x86 unbootable with Clang). Disable unreachable when objtool is in use (redundant and confuses things: instrumentation appears at unreachable locations). Link: https://lkml.kernel.org/r/20201203004437.389959-7-keescook@chromium.org Signed-off-by: Kees Cook Cc: Andrey Ryabinin Cc: Ard Biesheuvel Cc: Arnd Bergmann Cc: Dmitry Vyukov Cc: George Popescu Cc: Herbert Xu Cc: Linus Torvalds Cc: Marco Elver Cc: Masahiro Yamada Cc: Michal Marek Cc: Nathan Chancellor Cc: Nick Desaulniers Cc: Peter Oberparleiter Cc: Randy Dunlap Signed-off-by: Andrew Morton --- Documentation/dev-tools/ubsan.rst | 1 lib/Kconfig.ubsan | 82 +++++++++++++++++++--------- 2 files changed, 57 insertions(+), 26 deletions(-) --- a/Documentation/dev-tools/ubsan.rst~ubsan-remove-ubsan_misc-in-favor-of-individual-options +++ a/Documentation/dev-tools/ubsan.rst @@ -86,3 +86,4 @@ References .. _1: https://gcc.gnu.org/onlinedocs/gcc-4.9.0/gcc/Debugging-Options.html .. _2: https://gcc.gnu.org/onlinedocs/gcc/Debugging-Options.html +.. _3: https://clang.llvm.org/docs/UndefinedBehaviorSanitizer.html --- a/lib/Kconfig.ubsan~ubsan-remove-ubsan_misc-in-favor-of-individual-options +++ a/lib/Kconfig.ubsan @@ -84,48 +84,88 @@ config UBSAN_LOCAL_BOUNDS where an added offset (which may not be known statically) is out-of-bounds. -config UBSAN_MISC - bool "Enable all other Undefined Behavior sanity checks" - default UBSAN - help - This option enables all sanity checks that don't have their - own Kconfig options. Disable this if you only want to have - individually selected checks. - config UBSAN_SHIFT - def_bool UBSAN_MISC + bool "Perform checking for bit-shift overflows" + default UBSAN depends on $(cc-option,-fsanitize=shift) + help + This option enables -fsanitize=shift which checks for bit-shift + operations that overflow to the left or go switch to negative + for signed types. config UBSAN_DIV_ZERO - def_bool UBSAN_MISC + bool "Perform checking for integer divide-by-zero" depends on $(cc-option,-fsanitize=integer-divide-by-zero) + help + This option enables -fsanitize=integer-divide-by-zero which checks + for integer division by zero. This is effectively redundant with the + kernel's existing exception handling, though it can provide greater + debugging information under CONFIG_UBSAN_REPORT_FULL. config UBSAN_UNREACHABLE - def_bool UBSAN_MISC + bool "Perform checking for unreachable code" + # objtool already handles unreachable checking and gets angry about + # seeing UBSan instrumentation located in unreachable places. + depends on !STACK_VALIDATION depends on $(cc-option,-fsanitize=unreachable) + help + This option enables -fsanitize=unreachable which checks for control + flow reaching an expected-to-be-unreachable position. config UBSAN_SIGNED_OVERFLOW - def_bool UBSAN_MISC + bool "Perform checking for signed arithmetic overflow" + default UBSAN depends on $(cc-option,-fsanitize=signed-integer-overflow) + help + This option enables -fsanitize=signed-integer-overflow which checks + for overflow of any arithmetic operations with signed integers. config UBSAN_UNSIGNED_OVERFLOW - def_bool UBSAN_MISC + bool "Perform checking for unsigned arithmetic overflow" depends on $(cc-option,-fsanitize=unsigned-integer-overflow) + help + This option enables -fsanitize=unsigned-integer-overflow which checks + for overflow of any arithmetic operations with unsigned integers. This + currently causes x86 to fail to boot. config UBSAN_OBJECT_SIZE - def_bool UBSAN_MISC + bool "Perform checking for accesses beyond the end of objects" + default UBSAN # gcc hugely expands stack usage with -fsanitize=object-size # https://lore.kernel.org/lkml/CAHk-=wjPasyJrDuwDnpHJS2TuQfExwe=px-SzLeN8GFMAQJPmQ@mail.gmail.com/ depends on !CC_IS_GCC depends on $(cc-option,-fsanitize=object-size) + help + This option enables -fsanitize=object-size which checks for accesses + beyond the end of objects where the optimizer can determine both the + object being operated on and its size, usually seen with bad downcasts, + or access to struct members from NULL pointers. config UBSAN_BOOL - def_bool UBSAN_MISC + bool "Perform checking for non-boolean values used as boolean" + default UBSAN depends on $(cc-option,-fsanitize=bool) + help + This option enables -fsanitize=bool which checks for boolean values being + loaded that are neither 0 nor 1. config UBSAN_ENUM - def_bool UBSAN_MISC + bool "Perform checking for out of bounds enum values" + default UBSAN depends on $(cc-option,-fsanitize=enum) + help + This option enables -fsanitize=enum which checks for values being loaded + into an enum that are outside the range of given values for the given enum. + +config UBSAN_ALIGNMENT + bool "Perform checking for misaligned pointer usage" + default !HAVE_EFFICIENT_UNALIGNED_ACCESS + depends on !UBSAN_TRAP && !COMPILE_TEST + depends on $(cc-option,-fsanitize=alignment) + help + This option enables the check of unaligned memory accesses. + Enabling this option on architectures that support unaligned + accesses may produce a lot of false positives. config UBSAN_SANITIZE_ALL bool "Enable instrumentation for the entire kernel" @@ -138,16 +178,6 @@ config UBSAN_SANITIZE_ALL Enabling this option will get kernel image size increased significantly. -config UBSAN_ALIGNMENT - bool "Enable checks for pointers alignment" - default !HAVE_EFFICIENT_UNALIGNED_ACCESS - depends on !UBSAN_TRAP && !COMPILE_TEST - depends on $(cc-option,-fsanitize=alignment) - help - This option enables the check of unaligned memory accesses. - Enabling this option on architectures that support unaligned - accesses may produce a lot of false positives. - config TEST_UBSAN tristate "Module for testing for undefined behavior detection" depends on m _