From patchwork Wed Nov 20 01:06:34 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 11252949 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 B53C61390 for ; Wed, 20 Nov 2019 01:07:19 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id 144E920708 for ; Wed, 20 Nov 2019 01:07:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="GjW65mTR" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 144E920708 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=chromium.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernel-hardening-return-17406-patchwork-kernel-hardening=patchwork.kernel.org@lists.openwall.com Received: (qmail 26020 invoked by uid 550); 20 Nov 2019 01:06:58 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 25793 invoked from network); 20 Nov 2019 01:06:56 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=cO8TBOltsH4skyCZjRFi1jjLHEcJb6wGQF3Nty2AFlw=; b=GjW65mTRpHcwke1tPpXJc+tEroqq+/c02L1weluBXv2HYDmUvuJroQHtjQB47mZ+Dq XrKKO4SSKAvPWN92dzPW6/GSh6v84X+1ecqKm5cP0W3j1AZS9WEFrXlA9digFiGFRewB KhiECAt/oiWz0Q2+iz92oxoX7RzTYeQrdzJTo= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=cO8TBOltsH4skyCZjRFi1jjLHEcJb6wGQF3Nty2AFlw=; b=Klu8EFKd70LrRc0VHyGe6tqhpFFuTFoEzchVq3FApjpNl7agzBvR1+NGvqczKv34kV BtbpSTmW9ToFbyNIzP28X1JE6bglIsI9Wg10tmf2MPJrZN/MJM2d+mptovatZ8f8G97c DDFCgxOuRXrTmLnEpy520465fpo8OWv/26DXzcoPn8jNnH8Qk8sLpp2enYJTVDjLenNS dnRpcWYAHnp6iZb3AJ+sYKHegenoTouWW+Fnn/FgeTfWrh8YOedH1Y1Uw9Uyi008aTpX 8lupWVf/2f88xPCVtAhoN9YpXjfbCcLZHg9DviTaLk8yYB5PrNMn3E+lX29b7eEBXwHp dHYQ== X-Gm-Message-State: APjAAAUJzGl3isCVXiZfOc1YBcXDU8AbbfHC9IOHhX0DQ0RAY7nHXf9i LPxdjUoriOYXUe8Qw9T7ZKFMGA== X-Google-Smtp-Source: APXvYqyASvZYvBQ/e7CI9HnVv6bkAWB/563LT5YKo0qEsvHWgg7DJbmwdBC/nFhsf8xhjPvdZtXPKw== X-Received: by 2002:aa7:9f89:: with SMTP id z9mr651850pfr.123.1574212004404; Tue, 19 Nov 2019 17:06:44 -0800 (PST) From: Kees Cook To: Andrey Ryabinin Cc: Kees Cook , Elena Petrova , Alexander Potapenko , Dmitry Vyukov , Linus Torvalds , Dan Carpenter , "Gustavo A. R. Silva" , Arnd Bergmann , Ard Biesheuvel , Andrew Morton , kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com Subject: [PATCH 1/3] ubsan: Add trap instrumentation option Date: Tue, 19 Nov 2019 17:06:34 -0800 Message-Id: <20191120010636.27368-2-keescook@chromium.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20191120010636.27368-1-keescook@chromium.org> References: <20191120010636.27368-1-keescook@chromium.org> The Undefined Behavior Sanitizer can operate in two modes: warning reporting mode via lib/ubsan.c handler calls, or trap mode, which uses __builtin_trap() as the handler. Using lib/ubsan.c means the kernel image is about 5% larger (due to all the debugging text and reporting structures to capture details about the warning conditions). Using the trap mode, the image size changes are much smaller, though at the loss of the "warning only" mode. In order to give greater flexibility to system builders that want minimal changes to image size and are prepared to deal with kernel threads being killed, this introduces CONFIG_UBSAN_TRAP. The resulting image sizes comparison: text data bss dec hex filename 19533663 6183037 18554956 44271656 2a38828 vmlinux.stock 19991849 7618513 18874448 46484810 2c54d4a vmlinux.ubsan 19712181 6284181 18366540 44362902 2a4ec96 vmlinux.ubsan-trap CONFIG_UBSAN=y: image +4.8% (text +2.3%, data +18.9%) CONFIG_UBSAN_TRAP=y: image +0.2% (text +0.9%, data +1.6%) Suggested-by: Elena Petrova Signed-off-by: Kees Cook --- lib/Kconfig.ubsan | 15 +++++++++++++-- lib/Makefile | 2 ++ scripts/Makefile.ubsan | 9 +++++++-- 3 files changed, 22 insertions(+), 4 deletions(-) diff --git a/lib/Kconfig.ubsan b/lib/Kconfig.ubsan index 0e04fcb3ab3d..d69e8b21ebae 100644 --- a/lib/Kconfig.ubsan +++ b/lib/Kconfig.ubsan @@ -5,12 +5,23 @@ config ARCH_HAS_UBSAN_SANITIZE_ALL config UBSAN bool "Undefined behaviour sanity checker" help - This option enables undefined behaviour sanity checker + This option enables undefined behaviour sanity checker. Compile-time instrumentation is used to detect various undefined - behaviours in runtime. Various types of checks may be enabled + behaviours at runtime. Various types of checks may be enabled via boot parameter ubsan_handle (see: Documentation/dev-tools/ubsan.rst). +config UBSAN_TRAP + bool "On Sanitizer warnings, stop the offending kernel thread" + depends on UBSAN + depends on $(cc-option, -fsanitize-undefined-trap-on-error) + help + Building kernels with Sanitizer features enabled tends to grow + the kernel size by over 5%, due to adding all the debugging + text on failure paths. To avoid this, Sanitizer instrumentation + can just issue a trap. This reduces the kernel size overhead but + turns all warnings into full thread-killing exceptions. + config UBSAN_SANITIZE_ALL bool "Enable instrumentation for the entire kernel" depends on UBSAN diff --git a/lib/Makefile b/lib/Makefile index c5892807e06f..bc498bf0f52d 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -272,7 +272,9 @@ quiet_cmd_build_OID_registry = GEN $@ clean-files += oid_registry_data.c obj-$(CONFIG_UCS2_STRING) += ucs2_string.o +ifneq ($(CONFIG_UBSAN_TRAP),y) obj-$(CONFIG_UBSAN) += ubsan.o +endif UBSAN_SANITIZE_ubsan.o := n KASAN_SANITIZE_ubsan.o := n diff --git a/scripts/Makefile.ubsan b/scripts/Makefile.ubsan index 019771b845c5..668a91510bfe 100644 --- a/scripts/Makefile.ubsan +++ b/scripts/Makefile.ubsan @@ -1,5 +1,10 @@ # SPDX-License-Identifier: GPL-2.0 ifdef CONFIG_UBSAN + +ifdef CONFIG_UBSAN_ALIGNMENT + CFLAGS_UBSAN += $(call cc-option, -fsanitize=alignment) +endif + CFLAGS_UBSAN += $(call cc-option, -fsanitize=shift) CFLAGS_UBSAN += $(call cc-option, -fsanitize=integer-divide-by-zero) CFLAGS_UBSAN += $(call cc-option, -fsanitize=unreachable) @@ -9,8 +14,8 @@ ifdef CONFIG_UBSAN CFLAGS_UBSAN += $(call cc-option, -fsanitize=bool) CFLAGS_UBSAN += $(call cc-option, -fsanitize=enum) -ifdef CONFIG_UBSAN_ALIGNMENT - CFLAGS_UBSAN += $(call cc-option, -fsanitize=alignment) +ifdef CONFIG_UBSAN_TRAP + CFLAGS_UBSAN += $(call cc-option, -fsanitize-undefined-trap-on-error) endif # -fsanitize=* options makes GCC less smart than usual and