From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 118226 invoked by alias); 22 Mar 2018 17:00:48 -0000 Mailing-List: contact gnu-gabi-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Post: List-Help: List-Subscribe: Sender: gnu-gabi-owner@sourceware.org Received: (qmail 117136 invoked by uid 89); 22 Mar 2018 17:00:18 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Checked: by ClamAV 0.99.4 on sourceware.org X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.9 required=5.0 tests=BAYES_00,FREEMAIL_FROM,RCVD_IN_DNSWL_NONE,SPF_PASS,TIME_LIMIT_EXCEEDED autolearn=unavailable version=3.3.2 spammy=U*hjl X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,FREEMAIL_FROM,RCVD_IN_DNSWL_NONE,SPF_PASS,TIME_LIMIT_EXCEEDED autolearn=unavailable version=3.3.2 X-Spam-Checker-Version: SpamAssassin 3.3.2 (2011-06-06) on sourceware.org X-Spam-Level: X-HELO: mail-ot0-f172.google.com Received: from mail-ot0-f172.google.com (HELO mail-ot0-f172.google.com) (74.125.82.172) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Thu, 22 Mar 2018 17:00:04 +0000 Received: by mail-ot0-f172.google.com with SMTP id h8-v6so10219333oti.6 for ; Thu, 22 Mar 2018 10:00:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=zoHJ2c0lXfVw56+8SRvSeKWvpC3i5lNUgrhZ2TxBAVw=; b=vaePZQqXkzjpbxiUa8RFM7eYnMPckdSrhHg5mkedx2LKlnLZQkYhQip4SIA+CP9qZ4 4789ge7djnGQ/1OJFTP1g/nCR2CmvVXgJg71FbZ2otWBmDLhaQrJnL41jEg2Zpv1sm0t 1lDXFqhGnvAbYk+0fXAtYyd3avcjnQmiNeX1dRRXZw/2xv8Cmy3oUg+K8Hlp10J/hYlx Y+l0IPx87L+qrZQdsHKAfG2mvuLk1MqAEX4GZeCWPIYqKvyTeS9ArV9NDU1LGjhKxR9r Jt8HZW4ihi3c0wQuIVrJsrOHVhy7hG48688TuEuxK/Amk4F1KqsIs6lAfTNrs0rSxNze +M1w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=zoHJ2c0lXfVw56+8SRvSeKWvpC3i5lNUgrhZ2TxBAVw=; b=R4Dv2uKGJcPNxe+UqsUC9Gd4QljS6dvl0Ri2z50sRc/FFLDx66zvLtqb/mHm24UTIT T4SMOrmyoBGeg6EKpAWMr+8eDLCRnLSUfugdvivSWjJND2AfH2QL/ONWaiTjAFytB7dR lb5YSsy/mUfGCbARjEwwnBr9M8y1TCUARVbS7rKsHPA8nBZcOJgrstCNAxbN4+Iuf5bv NEqap7LYVvMCT4K7LwPdtPbtPNo+JolDQvAyL/qxJB28Al/o4s3+G3FBo4/CD5OuFnVI qbm3vAx/cE+Kt/bP3Agnyzc7fEHUUw6CBt8JUYva2ZNX3QUPKGMY91NkSGc58QeXEtWy mZ4Q== X-Gm-Message-State: AElRT7EifQ9v2WgZgdiao+cueYEv0E18Y8BV6/NKwQPSm8laJQfrxd3y cPTHWMgI0PCDzTSO8SQtnn6rZr+o15Sw5rqU0II= X-Google-Smtp-Source: AG47ELv4sF/DrT/sIHDUpsptXjvryaasSBu6Jue2tpCCzC+f0Kwp1MguWgx6IX4+uVO3/g4rNn5JxOHbMnJ6oTGbg8s= X-Received: by 2002:a9d:2aa1:: with SMTP id e30-v6mr15322057otb.7.1521738002784; Thu, 22 Mar 2018 10:00:02 -0700 (PDT) MIME-Version: 1.0 Received: by 10.74.10.20 with HTTP; Thu, 22 Mar 2018 10:00:02 -0700 (PDT) In-Reply-To: <874ll8uker.fsf@mid.deneb.enyo.de> References: <20180317133115.GA4681@gmail.com> <87370txhr1.fsf@mid.deneb.enyo.de> <3a203b82-1247-5538-4848-92c9227cc77e@redhat.com> <87po3wo589.fsf@mid.deneb.enyo.de> <76f5551d-e8dc-4915-e3d8-54a2305a5718@redhat.com> <874ll8uker.fsf@mid.deneb.enyo.de> From: "H.J. Lu" Date: Mon, 01 Jan 2018 00:00:00 -0000 Message-ID: Subject: Re: RFC: Audit external function called indirectly via GOT To: Florian Weimer Cc: "Carlos O'Donell" , Generic System V Application Binary Interface , gnu-gabi@sourceware.org Content-Type: text/plain; charset="UTF-8" X-IsSubscribed: yes X-SW-Source: 2018-q1/txt/msg00024.txt.bz2 On Thu, Mar 22, 2018 at 9:47 AM, Florian Weimer wrote: > * Carlos O'Donell: > >> Well, Levin's "Linker's and Loaders" >> https://www.iecc.com/linker/linker10.html, is the immediate reference >> that I have on my shelf, and that developers working on glibc/binutils >> should read. > > Thanks, I didn't know that. > >>> My understanding is that H.J.'s proposal requires changes when running >>> in non-audit mode. It certainly requires relinking all binaries, >>> perhaps even with special flags. >> >> It would require a relink only to fix existing binaries which are broken >> by the use of -fno-plt, which is not an option that has seen general use >> anywhere that I am aware of. > > I don't think that's actually true. BFD ld has not emitted > R_X86_64_JUMP_SLOT relocations with -z now for quite some time now. > This optimization predates -fno-plt. > Not true with binutils 2.30: [hjl@gnu-bdx-1 include]$ readelf -d /bin/ld | grep NOW 0x0000000000000018 (BIND_NOW) 0x000000006ffffffb (FLAGS_1) Flags: NOW PIE [hjl@gnu-bdx-1 include]$ readelf -rW /bin/ld | grep JUMP_SLOT 00000000001b0868 0000000100000007 R_X86_64_JUMP_SLOT 0000000000000000 getenv@GLIBC_2.2.5 + 0 ... -- H.J.