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=-8.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham 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 04148C32789 for ; Fri, 2 Nov 2018 15:57:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B909920657 for ; Fri, 2 Nov 2018 15:57:24 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B909920657 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arndb.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727989AbeKCBE4 (ORCPT ); Fri, 2 Nov 2018 21:04:56 -0400 Received: from mout.kundenserver.de ([217.72.192.73]:46769 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726700AbeKCBE4 (ORCPT ); Fri, 2 Nov 2018 21:04:56 -0400 Received: from wuerfel.lan ([109.192.41.194]) by mrelayeu.kundenserver.de (mreue106 [212.227.15.145]) with ESMTPA (Nemesis) id 1MEFCF-1gQYJg1s9d-00AD8f; Fri, 02 Nov 2018 16:57:13 +0100 Received: from wuerfel.lan ([109.192.41.194]) by mrelayeu.kundenserver.de (mreue106 [212.227.15.145]) with ESMTPA (Nemesis) id 1MEFCF-1gQYJg1s9d-00AD8f; Fri, 02 Nov 2018 16:57:13 +0100 From: Arnd Bergmann To: Andrew Morton Cc: Masahiro Yamada , Al Viro , Arnd Bergmann , Changbin Du , Marc Zyngier , =?UTF-8?q?Alex=20Benn=C3=A9e?= , Dave Martin , Kees Cook , "Levin, Alexander (Sasha Levin)" , linux-kernel@vger.kernel.org Subject: [PATCH] copy_{to,from}_user(): fix compile-time sanity checks with gcc -Og Date: Fri, 2 Nov 2018 16:56:58 +0100 Message-Id: <20181102155710.2299475-1-arnd@arndb.de> X-Mailer: git-send-email 2.18.0 X-Provags-ID: V03:K1:X+qVvBb/GzVwHU4DkPImdxvpq9fq/2URLIt0PbJ2CcEgtbtM1Pw mV8YFLzx95+HCpvZ2xZTrbo8c9Uj0QCancrFnk1SwmDVootXzosRAWyIOOdTG9OCu9ffdp+ epWOLpUuN6IidNTa4RMB4/7F/4ausEYhsZ48Sbe8K5/tZGDI6fioty7GoOjBtqEpkGnnTXV wRL1Ge0MbDBIXRDuGqm4g== X-UI-Out-Filterresults: notjunk:1;V01:K0:exWrVnSCmUE=:owrhYdF4wLavopmMG2oplp fRiupg9zSBp825elD5AYIIKJkEXN5mBju4BqcwEUTdr3VZ/+xX9697i+m/ydCFJZoK2oCaPue rXMqQxz/ZCKCcy3bDv2E+GwVrHGKKbfer0o5RayGttd76ecwraLhf6lczF/JLvhSZWLq99EVB 0kMarh5EKFUOG61zclvXbXPp+Of542lO9F1Nyu3J0LHqDQjoIQZD4zmqak6ft7j7ucEZpUcja WzA9W+Rj871w0FTTozedmE5ZpNxT/3K85pamfcvRWRheKQzfTlv+f0QvZG7eg3hlSvOVXT1rM uTwGmtmY1IyYWyZQQwn3DX0GPim5vXWzJKSIuiLsQI9UskP617UvQ6lfoD338AYjRhJRc2qOT 37Giwn7DTPwQ+rKVt3WfOZ2zRz6iKuxvMdnXkv/KFIC0sm1ImU3dlRl8Ofn00HuKKEbd0+x+i kVx4fvwqTO7kN5hYiHUHeXdA1bw74doNACyT/LSCHO5kz927A6jtLz9pDooDfIMBpGrGjGgF3 EeA+iOnsgsitXVh8MZJIxOHut/liMPkcA1F1LNAMqIDEdZUsbpEz6BPo0VlNLgi4WhkA7JYSb mRGx9cGfiBT1LbdPIuTPu8NPQ6vrSsTriGmKEqF0mv3/z87L7h4FC9wMHCvGwV0R2WSVuvxhk kDLHLYLs54qGB5+a9HnBbrJQb1xBz7GRJHj5MTZudzNLu/ZijV9HhbVD2b4TaO4q5m8Y= Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When CONFIG_CC_OPTIMIZE_FOR_DEBUGGING is set, we get countless warnings like In function 'check_copy_size', inlined from 'copy_from_user' at include/linux/uaccess.h:146:6, inlined from '__copy_siginfo_from_user' at kernel/signal.c:3032:6: include/linux/thread_info.h:147:4: error: call to '__bad_copy_to' declared with attribute error: copy destination size is too small It seems that constant propagation doesn't work well enough to make this code reliable, so turn it off for that configuration. Cc: Changbin Du Cc: Al Viro Signed-off-by: Arnd Bergmann --- include/linux/thread_info.h | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/include/linux/thread_info.h b/include/linux/thread_info.h index 8d8821b3689a..762f379bdf5d 100644 --- a/include/linux/thread_info.h +++ b/include/linux/thread_info.h @@ -138,6 +138,11 @@ static __always_inline bool check_copy_size(const void *addr, size_t bytes, bool is_source) { int sz = __compiletime_object_size(addr); + + /* constant propagation doesn't work well with -Og */ + if (IS_ENABLED(CONFIG_CC_OPTIMIZE_FOR_DEBUGGING)) + return true; + if (unlikely(sz >= 0 && sz < bytes)) { if (!__builtin_constant_p(bytes)) copy_overflow(sz, bytes); -- 2.18.0