From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by sourceware.org (Postfix) with ESMTPS id 2E4A73AA8000 for ; Thu, 17 Nov 2022 13:58:08 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 2E4A73AA8000 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1668693487; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=LOXq3wtyX13WFLhuoNkaX6Kj+6HfTJDVmrXblsh+ifw=; b=U5g9x7PrY5KiQrvrNJbFhAtyzgUInjF9IaKGqkwLEAi/046SeXSbA14tqvHOjE/Ri2WLqR 9kyqfhKeBDl3zGG3yZQB1hscFAFF3aB3rLSSFsugnmLmmnlV7qKvlLedg6xN1XNfGFne6I 4JmilJFF48YGcPDf+Wt1gqVihJCEcfY= Received: from mail-il1-f200.google.com (mail-il1-f200.google.com [209.85.166.200]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-606-4mUsksKjNfqeFGNBABDbyg-1; Thu, 17 Nov 2022 08:58:06 -0500 X-MC-Unique: 4mUsksKjNfqeFGNBABDbyg-1 Received: by mail-il1-f200.google.com with SMTP id j7-20020a056e02154700b003025b3c0ea3so1237694ilu.10 for ; Thu, 17 Nov 2022 05:58:06 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=LOXq3wtyX13WFLhuoNkaX6Kj+6HfTJDVmrXblsh+ifw=; b=vmd2lpgLjPqxDh7sUDwBqpcD6VTWQ+KDER15cOuCX2uGaOIKQfvP45YsR1JIJSYUWW CDtyeAY7skxHl8yQNVap5F8367kTU6cM9sLjATXTUXRS5UWzhy5VYQhfJ39slS8nNfj8 G0hJYFEtFX1GPCJU8TP0NSlr2X8RJKVYOdIPJ38PfjL/88svBdix0q125PCRv7LwE7CG Rex3bVows4EC3CI7yEbeHNA8D8aH8LE8FeLkyqS/W20ZDEnxWD3xRGFZhh/7teTbHvT9 d8GqOsPnPYGVSklAcTA1iGh90Uh9pvu06Ydx7mrZHqIgN5OiskFlv7rNcitoc9wlCmgT 0TZg== X-Gm-Message-State: ANoB5pmvp5PAkMisQNHhUN5fWM4lE9tCZv0tq295cg75wXqTZB2jln4T fP8+Xahy8ffRRmNxUsBp8EUPl0G3VY0qK0ayst2anVU/V0p4xqMoD1u8KXAC7jeijIaLOJv9WyP BlKFiF8BvQKB2fF5ca1xKMmw= X-Received: by 2002:a5d:9ecc:0:b0:6d9:c117:7a1c with SMTP id a12-20020a5d9ecc000000b006d9c1177a1cmr1323355ioe.187.1668693485435; Thu, 17 Nov 2022 05:58:05 -0800 (PST) X-Google-Smtp-Source: AA0mqf53pARBvhWMnUAQGhMGsgen/1vgq43YO5pwySDHY2m2S2OnoUTJOOvyareX1TT6DSgcMlnhJNMPDqvYkKMWOv8= X-Received: by 2002:a5d:9ecc:0:b0:6d9:c117:7a1c with SMTP id a12-20020a5d9ecc000000b006d9c1177a1cmr1323343ioe.187.1668693485143; Thu, 17 Nov 2022 05:58:05 -0800 (PST) MIME-Version: 1.0 References: <24ed5604-305a-4343-a1b6-a789e4723849@app.fastmail.com> <251923e7-57be-1611-be10-49c3067adf0d@cs.ucla.edu> <093f16f3-eae0-dcdc-fb52-2cba3c3e23b4@cs.ucla.edu> In-Reply-To: <093f16f3-eae0-dcdc-fb52-2cba3c3e23b4@cs.ucla.edu> From: Jason Merrill Date: Thu, 17 Nov 2022 08:57:53 -0500 Message-ID: Subject: Re: How can Autoconf help with the transition to stricter compilation defaults? To: Paul Eggert Cc: Aaron Ballman , Zack Weinberg , c-std-porting@lists.linux.dev, autoconf@gnu.org, gcc@gcc.gnu.org, cfe-commits@lists.llvm.org, Gnulib bugs X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: multipart/alternative; boundary="0000000000006bdf3a05edaafa6c" X-Spam-Status: No, score=-6.0 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,HTML_MESSAGE,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H2,SPF_HELO_NONE,SPF_NONE,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: --0000000000006bdf3a05edaafa6c Content-Type: text/plain; charset="UTF-8" On Sat, Nov 12, 2022 at 7:44 PM Paul Eggert wrote: > On 2022-11-11 07:11, Aaron Ballman wrote: > > Clang doesn't require such a linker (we work with various system > linkers). > > As long as the system linkers continue to work as they have > traditionally worked, we're fine. > > > the frontend perspective, we can't tell the difference between > > "trust me this is safe because it never gets executed" and "this is a > > CVE" > > If some system linker ever attempts to reject links with mismatched > signatures, Autoconf-generated code will need to have a way to shut that > off. I hope Clang maintainers can be cajoled into supporting that, if > the time comes. Perhaps there can be a #pragma, or a compile-time > option, to do that. > There has been discussion of the problems with compile-time options elsewhere in the thread, but the #pragma idea sounds promising, as older compilers can just ignore it. Jason --0000000000006bdf3a05edaafa6c--