From patchwork Wed Oct 19 15:37:19 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nathan Chancellor X-Patchwork-Id: 13012061 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5A8A6C43217 for ; Wed, 19 Oct 2022 15:42:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232540AbiJSPm4 (ORCPT ); Wed, 19 Oct 2022 11:42:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34282 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231166AbiJSPmV (ORCPT ); Wed, 19 Oct 2022 11:42:21 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2F56017426; Wed, 19 Oct 2022 08:38:15 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 5160EB824B0; Wed, 19 Oct 2022 15:37:23 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 79A20C4347C; Wed, 19 Oct 2022 15:37:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1666193842; bh=JRwAyHnjrSY03iEK2UKGtcgr2ehNnH9vwZJpBiLAoiY=; h=Date:From:To:Cc:Subject:From; b=rdDLnjfbZF01xbQOhru7EnqH+Ewbk9fsNyDOUpL3Y4xRw0b61GJ5SXvEcKn7qZm10 i9gOgMcvjdqZAL0zhZqN2Xiq4OweM8IcwJKC4hvgllOmamT3Gzbcb9Z1KroSX2dQfm ZlZrsCHoT+Ww2bSM6WN9Elic9hpx8qkl8iGcWjhW8u83fxwyER1+rVZiVEH+A0RU0O /cVQ5LIXHJ2Tmx3KYx7V6KVawsnV610LmNyHjNnk6s4EylkQpiar/HVBxXkJgIosQG IdaeuMuso4QH2fIZGUO4mDxYu+6je++vaRD+fSerOnaNpRrVF3YniHhsA4v9LtE4Id PGa/VPMFLXDlQ== Date: Wed, 19 Oct 2022 08:37:19 -0700 From: Nathan Chancellor To: Kees Cook , Alexander Potapenko , Andrew Morton Cc: linux-hardening@vger.kernel.org, linux-kernel@vger.kernel.org, llvm@lists.linux.dev, kasan-dev@googlegroups.com, linux-mm@kvack.org Subject: -Wmacro-redefined in include/linux/fortify-string.h Message-ID: MIME-Version: 1.0 Content-Disposition: inline Precedence: bulk List-ID: X-Mailing-List: linux-hardening@vger.kernel.org Hi all, I am seeing the following set of warnings when building an x86_64 configuration that has CONFIG_FORTIFY_SOURCE=y and CONFIG_KMSAN=y: In file included from scripts/mod/devicetable-offsets.c:3: In file included from ./include/linux/mod_devicetable.h:13: In file included from ./include/linux/uuid.h:12: In file included from ./include/linux/string.h:253: ./include/linux/fortify-string.h:496:9: error: 'memcpy' macro redefined [-Werror,-Wmacro-redefined] #define memcpy(p, q, s) __fortify_memcpy_chk(p, q, s, \ ^ ./arch/x86/include/asm/string_64.h:17:9: note: previous definition is here #define memcpy __msan_memcpy ^ In file included from scripts/mod/devicetable-offsets.c:3: In file included from ./include/linux/mod_devicetable.h:13: In file included from ./include/linux/uuid.h:12: In file included from ./include/linux/string.h:253: ./include/linux/fortify-string.h:500:9: error: 'memmove' macro redefined [-Werror,-Wmacro-redefined] #define memmove(p, q, s) __fortify_memcpy_chk(p, q, s, \ ^ ./arch/x86/include/asm/string_64.h:73:9: note: previous definition is here #define memmove __msan_memmove ^ 2 errors generated. I can see that commit ff901d80fff6 ("x86: kmsan: use __msan_ string functions where possible.") appears to include a fix up for this warning with memset() but not memcpy() or memmove(). If I apply a similar fix up like so: or is there a different obvious fix that I am missing? Cheers, Nathan diff --git a/include/linux/fortify-string.h b/include/linux/fortify-string.h index 4029fe368a4f..718ee17b31e3 100644 --- a/include/linux/fortify-string.h +++ b/include/linux/fortify-string.h @@ -493,6 +493,7 @@ __FORTIFY_INLINE bool fortify_memcpy_chk(__kernel_size_t size, * __struct_size() vs __member_size() must be captured here to avoid * evaluating argument side-effects further into the macro layers. */ +#ifndef CONFIG_KMSAN #define memcpy(p, q, s) __fortify_memcpy_chk(p, q, s, \ __struct_size(p), __struct_size(q), \ __member_size(p), __member_size(q), \ @@ -501,6 +502,7 @@ __FORTIFY_INLINE bool fortify_memcpy_chk(__kernel_size_t size, __struct_size(p), __struct_size(q), \ __member_size(p), __member_size(q), \ memmove) +#endif extern void *__real_memscan(void *, int, __kernel_size_t) __RENAME(memscan); __FORTIFY_INLINE void *memscan(void * const POS0 p, int c, __kernel_size_t size) Then the instances of -Wmacro-redefined disappear but the fortify tests no longer pass for somewhat obvious reasons: warning: unsafe memcpy() usage lacked '__read_overflow2' symbol in lib/test_fortify/read_overflow2-memcpy.c warning: unsafe memmove() usage lacked '__read_overflow2' symbol in lib/test_fortify/read_overflow2-memmove.c warning: unsafe memcpy() usage lacked '__read_overflow2_field' symbol in lib/test_fortify/read_overflow2_field-memcpy.c warning: unsafe memmove() usage lacked '__read_overflow2_field' symbol in lib/test_fortify/read_overflow2_field-memmove.c warning: unsafe memcpy() usage lacked '__write_overflow' symbol in lib/test_fortify/write_overflow-memcpy.c warning: unsafe memmove() usage lacked '__write_overflow' symbol in lib/test_fortify/write_overflow-memmove.c warning: unsafe memset() usage lacked '__write_overflow' symbol in lib/test_fortify/write_overflow-memset.c warning: unsafe memcpy() usage lacked '__write_overflow_field' symbol in lib/test_fortify/write_overflow_field-memcpy.c warning: unsafe memmove() usage lacked '__write_overflow_field' symbol in lib/test_fortify/write_overflow_field-memmove.c warning: unsafe memset() usage lacked '__write_overflow_field' symbol in lib/test_fortify/write_overflow_field-memset.c Should CONFIG_KMSAN depend on CONFIG_FORTIFY_SOURCE=n like so? It seems like the two features are incompatible if I am reading ff901d80fff6 correctly. diff --git a/lib/Kconfig.kmsan b/lib/Kconfig.kmsan index b2489dd6503f..6a681621e3c5 100644 --- a/lib/Kconfig.kmsan +++ b/lib/Kconfig.kmsan @@ -11,7 +11,7 @@ config HAVE_KMSAN_COMPILER config KMSAN bool "KMSAN: detector of uninitialized values use" depends on HAVE_ARCH_KMSAN && HAVE_KMSAN_COMPILER - depends on SLUB && DEBUG_KERNEL && !KASAN && !KCSAN + depends on SLUB && DEBUG_KERNEL && !KASAN && !KCSAN && !FORTIFY_SOURCE select STACKDEPOT select STACKDEPOT_ALWAYS_INIT help