From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/446 Path: news.gmane.org!not-for-mail From: Solar Designer Newsgroups: gmane.linux.lib.musl.general Subject: fd 0-2 on SUID/SGID program startup Date: Mon, 22 Aug 2011 21:07:54 +0400 Message-ID: <20110822170754.GA16515@openwall.com> Reply-To: musl@lists.openwall.com NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: dough.gmane.org 1314032893 16364 80.91.229.12 (22 Aug 2011 17:08:13 GMT) X-Complaints-To: usenet@dough.gmane.org NNTP-Posting-Date: Mon, 22 Aug 2011 17:08:13 +0000 (UTC) To: musl@lists.openwall.com Original-X-From: musl-return-447-gllmg-musl=m.gmane.org@lists.openwall.com Mon Aug 22 19:08:10 2011 Return-path: Envelope-to: gllmg-musl@lo.gmane.org Original-Received: from mother.openwall.net ([195.42.179.200]) by lo.gmane.org with smtp (Exim 4.69) (envelope-from ) id 1QvXys-00073E-0n for gllmg-musl@lo.gmane.org; Mon, 22 Aug 2011 19:08:10 +0200 Original-Received: (qmail 24005 invoked by uid 550); 22 Aug 2011 17:08:09 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: Original-Received: (qmail 23995 invoked from network); 22 Aug 2011 17:08:09 -0000 Content-Disposition: inline User-Agent: Mutt/1.4.2.3i Xref: news.gmane.org gmane.linux.lib.musl.general:446 Archived-At: Rich, As you're probably aware, glibc makes sure that fd 0-2 are open on SUID/SGID program startup (opening them to /dev/null / /dev/full if they're not already open). This is needed to prevent misdirected reads/writes by programs that use those well-known fd's (in fact, even libc itself does) yet also open other files/sockets/whatever (so it may get opened on one of these special fd's if they're not already taken). I think musl must have the same countermeasure. I think it lacks it currently. Do you agree? Alexander