From owner-freebsd-security@freebsd.org Sat Oct 6 18:46:47 2018 Return-Path: Delivered-To: freebsd-security@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id B213810C2E33 for ; Sat, 6 Oct 2018 18:46:47 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from kib.kiev.ua (kib.kiev.ua [IPv6:2001:470:d5e7:1::1]) (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 190EB7F05B for ; Sat, 6 Oct 2018 18:46:46 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from tom.home (kib@localhost [127.0.0.1]) by kib.kiev.ua (8.15.2/8.15.2) with ESMTPS id w96Ikag5046050 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO) for ; Sat, 6 Oct 2018 21:46:39 +0300 (EEST) (envelope-from kostikbel@gmail.com) DKIM-Filter: OpenDKIM Filter v2.10.3 kib.kiev.ua w96Ikag5046050 Received: (from kostik@localhost) by tom.home (8.15.2/8.15.2/Submit) id w96IkaEr046049 for freebsd-security@freebsd.org; Sat, 6 Oct 2018 21:46:36 +0300 (EEST) (envelope-from kostikbel@gmail.com) X-Authentication-Warning: tom.home: kostik set sender to kostikbel@gmail.com using -f Date: Sat, 6 Oct 2018 21:46:36 +0300 From: Konstantin Belousov To: freebsd-security@freebsd.org Subject: Re: [FreeBSD-Announce] FreeBSD Security Advisory FreeBSD-SA-18:12.elf Message-ID: <20181006184636.GT5335@kib.kiev.ua> References: <20180912054309.61C6B13269@freefall.freebsd.org> <20181006173525.GC813@lena.kiev> <20181006182104.GS5335@kib.kiev.ua> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181006182104.GS5335@kib.kiev.ua> User-Agent: Mutt/1.10.1 (2018-07-13) X-Spam-Status: No, score=-1.0 required=5.0 tests=ALL_TRUSTED,BAYES_00, DKIM_ADSP_CUSTOM_MED,FORGED_GMAIL_RCVD,FREEMAIL_FROM, NML_ADSP_CUSTOM_MED autolearn=no autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on tom.home X-BeenThere: freebsd-security@freebsd.org X-Mailman-Version: 2.1.27 Precedence: list List-Id: "Security issues \[members-only posting\]" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 06 Oct 2018 18:46:47 -0000 On Sat, Oct 06, 2018 at 09:21:04PM +0300, Konstantin Belousov wrote: > On Sat, Oct 06, 2018 at 08:35:26PM +0300, Lena@lena.kiev.ua wrote: > > > Insufficient validation was performed in the ELF header parser, and malformed > > > or otherwise invalid ELF binaries were not rejected as they should be. > > > > What is invalid in the /usr/local/share/google-earth/googleearth-bin > > binary of the port google-earth-7.1.5.1557,3 ? > > > > FreeBSD 11.2-RELEASE-p4 Sep 27 GENERIC i386, the binary: > > https://drive.google.com/file/d/1SgHk8ijSp2F9UcQGlx44psT832TdIEL0/view > > > > ~ $ googleearth > > Invalid PT_INTERP > > exec: ./googleearth-bin: Exec format error > > ~ $ readelf --program-headers /usr/local/share/google-earth/googleearth-bin > > > > Elf file type is EXEC (Executable file) > > Entry point 0x8048650 > > There are 8 program headers, starting at offset 52 > > > > Program Headers: > > Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align > > PHDR 0x000034 0x08048034 0x08048034 0x00100 0x00100 R E 0x4 > > INTERP 0x000134 0x08048134 0x08048134 0x00011 0x00011 R 0x1 > > [Requesting program interpreter: /lib/ld-linux.so.2] > As you see, the file delcares that file/memory length of the interpreter > name' segment is 0x11 == 16 decimal. But the string does not end on > byte 16, which is not NUL. We tighten the checks and do require that > PT_INTERP string is valid by checking that it is NUL-terminated at the > offset declared by the size. As emaste pointed out, I am off by one, i.e. replace 16 by 17 in the text above.