From owner-svn-src-head@FreeBSD.ORG  Thu Apr  9 13:45:18 2015
Return-Path: <owner-svn-src-head@FreeBSD.ORG>
Delivered-To: svn-src-head@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115])
 (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits))
 (No client certificate requested)
 by hub.freebsd.org (Postfix) with ESMTPS id 553FD2D2;
 Thu,  9 Apr 2015 13:45:18 +0000 (UTC)
Received: from svn.freebsd.org (svn.freebsd.org
 [IPv6:2001:1900:2254:2068::e6a:0])
 (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))
 (Client did not present a certificate)
 by mx1.freebsd.org (Postfix) with ESMTPS id 40897B43;
 Thu,  9 Apr 2015 13:45:18 +0000 (UTC)
Received: from svn.freebsd.org ([127.0.1.70])
 by svn.freebsd.org (8.14.9/8.14.9) with ESMTP id t39DjIgQ016703;
 Thu, 9 Apr 2015 13:45:18 GMT (envelope-from emaste@FreeBSD.org)
Received: (from emaste@localhost)
 by svn.freebsd.org (8.14.9/8.14.9/Submit) id t39DjIIs016702;
 Thu, 9 Apr 2015 13:45:18 GMT (envelope-from emaste@FreeBSD.org)
Message-Id: <201504091345.t39DjIIs016702@svn.freebsd.org>
X-Authentication-Warning: svn.freebsd.org: emaste set sender to
 emaste@FreeBSD.org using -f
From: Ed Maste <emaste@FreeBSD.org>
Date: Thu, 9 Apr 2015 13:45:18 +0000 (UTC)
To: src-committers@freebsd.org, svn-src-all@freebsd.org,
 svn-src-head@freebsd.org
Subject: svn commit: r281311 - head/usr.bin/ar
X-SVN-Group: head
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
X-BeenThere: svn-src-head@freebsd.org
X-Mailman-Version: 2.1.18-1
Precedence: list
List-Id: SVN commit messages for the src tree for head/-current
 <svn-src-head.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/options/svn-src-head>,
 <mailto:svn-src-head-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/svn-src-head/>
List-Post: <mailto:svn-src-head@freebsd.org>
List-Help: <mailto:svn-src-head-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/svn-src-head>,
 <mailto:svn-src-head-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Thu, 09 Apr 2015 13:45:18 -0000

Author: emaste
Date: Thu Apr  9 13:45:17 2015
New Revision: 281311
URL: https://svnweb.freebsd.org/changeset/base/281311

Log:
  ar: Disallow directory traversal
  
  Set ARCHIVE_EXTRACT_SECURE_SYMLINKS and ARCHIVE_EXTRACT_SECURE_NODOTDOT
  as in bsdtar to prevent extraction of archive entries whose pathnames
  contain .. or whose target directory would be altered by a symlink.
  Also disallow absolute pathnames.
  
  We don't currently provide an option to disable this behaviour (as
  bsdtar's -P does). It is unlikely to be a problem in practice for ar(1),
  but the -P option is not currently used and available if we want to
  consider it for this purpose.
  
  Differential Revision:	https://reviews.freebsd.org/D1524
  Reported by:	Alexander Cherepanov <cherepan@mccme.ru>
  Approved by:	delphij
  Obtained from:	ELF tool chain ar, Ticket #474
  MFC after:	1 week
  Relnotes:	Yes
  Sponsored by:	The FreeBSD Foundation

Modified:
  head/usr.bin/ar/read.c

Modified: head/usr.bin/ar/read.c
==============================================================================
--- head/usr.bin/ar/read.c	Thu Apr  9 13:09:05 2015	(r281310)
+++ head/usr.bin/ar/read.c	Thu Apr  9 13:45:17 2015	(r281311)
@@ -187,7 +187,15 @@ read_archive(struct bsdar *bsdar, char m
 
 				if (bsdar->options & AR_V)
 					(void)fprintf(stdout, "x - %s\n", name);
-				flags = 0;
+				/* Disallow absolute paths. */
+				if (name[0] == '/') {
+					bsdar_warnc(bsdar, 0,
+					    "Absolute path '%s'", name);
+					continue;
+				}
+				/* Basic path security flags. */
+				flags = ARCHIVE_EXTRACT_SECURE_SYMLINKS | \
+				    ARCHIVE_EXTRACT_SECURE_NODOTDOT;
 				if (bsdar->options & AR_O)
 					flags |= ARCHIVE_EXTRACT_TIME;