From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 73442 invoked by alias); 15 Apr 2016 15:08:46 -0000 Mailing-List: contact binutils-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: binutils-owner@sourceware.org Received: (qmail 73433 invoked by uid 89); 15 Apr 2016 15:08:45 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.2 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_NONE,RP_MATCHES_RCVD,SPF_PASS autolearn=ham version=3.3.2 spammy=offer, insight X-HELO: mailapp01.imgtec.com Received: from mailapp01.imgtec.com (HELO mailapp01.imgtec.com) (195.59.15.196) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Fri, 15 Apr 2016 15:08:44 +0000 Received: from HHMAIL01.hh.imgtec.org (unknown [10.100.10.19]) by Websense Email with ESMTPS id 9726E48241F83 for ; Fri, 15 Apr 2016 16:08:38 +0100 (IST) Received: from hhmail02.hh.imgtec.org ([fe80::5400:d33e:81a4:f775]) by HHMAIL01.hh.imgtec.org ([fe80::710b:f219:72bc:e0b3%26]) with mapi id 14.03.0266.001; Fri, 15 Apr 2016 16:08:41 +0100 From: Matthew Fortune To: "binutils@sourceware.org" CC: Anibal Monsalve Salazar Subject: [RFD] How legal is it to delete dynamic tags? Date: Fri, 15 Apr 2016 15:08:00 -0000 Message-ID: <6D39441BF12EF246A7ABCE6654B023537E3D685D@hhmail02.hh.imgtec.org> Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-IsSubscribed: yes X-SW-Source: 2016-04/txt/msg00233.txt.bz2 I have a bug report from Debian showing that the DT_MIPS_RLD_MAP_REL tag (introduced on MIPS to support shared library debug with PIE) can be corrupted by a program called chrpath. https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=3D818909#43 chrpath is designed to alter or remove DT_RPATH entries. Removal is a problem when such an entry precedes DT_MIPS_RLD_MAP_REL as the relative offset stored in DT_MIPS_RLD_MAP_REL then points to the wrong address. Firstly, to what extent is it OK to just delete a dynamic tag rather than set it to DT_NULL? Secondly was it a bad decision to create a slot-relative dynamic tag? I.e. If I were to fix chrpath to know that DT_MIPS_RLD_MAP_REL needs updating... are there likely to be more utilities out there that fiddle with dynamic tags in this way? Thanks for any insight you can offer. Matthew