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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 37977C77B7A for ; Tue, 30 May 2023 20:18:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233293AbjE3USx (ORCPT ); Tue, 30 May 2023 16:18:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51892 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229893AbjE3USw (ORCPT ); Tue, 30 May 2023 16:18:52 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2AF82FC for ; Tue, 30 May 2023 13:18:50 -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 dfw.source.kernel.org (Postfix) with ESMTPS id 9A5F06332B for ; Tue, 30 May 2023 20:18:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E359EC433D2; Tue, 30 May 2023 20:18:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1685477929; bh=uJKakDyU1Ib3h7XLjVs5L1o3JJg0UqiYg7X2hPefHfg=; h=Date:To:From:Subject:From; b=laKsNqiShHqM0eyRSaSknT1yPxzt1q4mcaQVlo3pLNJ8pxJJqhnbmNG5NCOBiVAAN qtw7VsMZW9WbivFbi4FN6DzNfbo5GELlivvOxfxj8yBuvfZpVeal7sBQeakKKRKj4B DI+lpwYcRamZN8bit0vHWm/O2TFKxRY3VgjrDM+8= Date: Tue, 30 May 2023 13:18:48 -0700 To: mm-commits@vger.kernel.org, ndesaulniers@google.com, nathan@kernel.org, keescook@chromium.org, elver@google.com, dvyukov@google.com, andy@kernel.org, glider@google.com, akpm@linux-foundation.org From: Andrew Morton Subject: + string-use-__builtin_memcpy-in-strlcpy-strlcat.patch added to mm-hotfixes-unstable branch Message-Id: <20230530201848.E359EC433D2@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: string: use __builtin_memcpy() in strlcpy/strlcat has been added to the -mm mm-hotfixes-unstable branch. Its filename is string-use-__builtin_memcpy-in-strlcpy-strlcat.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/string-use-__builtin_memcpy-in-strlcpy-strlcat.patch This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Alexander Potapenko Subject: string: use __builtin_memcpy() in strlcpy/strlcat Date: Tue, 30 May 2023 10:39:11 +0200 lib/string.c is built with -ffreestanding, which prevents the compiler from replacing certain functions with calls to their library versions. On the other hand, this also prevents Clang and GCC from instrumenting calls to memcpy() when building with KASAN, KCSAN or KMSAN: - KASAN normally replaces memcpy() with __asan_memcpy() with the additional cc-param,asan-kernel-mem-intrinsic-prefix=1; - KCSAN and KMSAN replace memcpy() with __tsan_memcpy() and __msan_memcpy() by default. To let the tools catch memory accesses from strlcpy/strlcat, replace the calls to memcpy() with __builtin_memcpy(), which KASAN, KCSAN and KMSAN are able to replace even in -ffreestanding mode. This preserves the behavior in normal builds (__builtin_memcpy() ends up being replaced with memcpy()), and does not introduce new instrumentation in unwanted places, as strlcpy/strlcat are already instrumented. Link: https://lkml.kernel.org/r/20230530083911.1104336-1-glider@google.com Link: https://lore.kernel.org/all/20230224085942.1791837-1-elver@google.com/ Signed-off-by: Alexander Potapenko Suggested-by: Marco Elver Acked-by: Kees Cook Reviewed-by: Marco Elver Cc: Andy Shevchenko Cc: Dmitry Vyukov Cc: Nathan Chancellor Cc: Nick Desaulniers Signed-off-by: Andrew Morton --- lib/string.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/lib/string.c~string-use-__builtin_memcpy-in-strlcpy-strlcat +++ a/lib/string.c @@ -110,7 +110,7 @@ size_t strlcpy(char *dest, const char *s if (size) { size_t len = (ret >= size) ? size - 1 : ret; - memcpy(dest, src, len); + __builtin_memcpy(dest, src, len); dest[len] = '\0'; } return ret; @@ -260,7 +260,7 @@ size_t strlcat(char *dest, const char *s count -= dsize; if (len >= count) len = count-1; - memcpy(dest, src, len); + __builtin_memcpy(dest, src, len); dest[len] = 0; return res; } _ Patches currently in -mm which might be from glider@google.com are string-use-__builtin_memcpy-in-strlcpy-strlcat.patch