From owner-freebsd-current Sun Nov 3 11: 1:44 2002 Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id AB0FC37B401 for ; Sun, 3 Nov 2002 11:01:43 -0800 (PST) Received: from fledge.watson.org (fledge.watson.org [204.156.12.50]) by mx1.FreeBSD.org (Postfix) with ESMTP id B332743E42 for ; Sun, 3 Nov 2002 11:01:42 -0800 (PST) (envelope-from robert@fledge.watson.org) Received: from fledge.watson.org (fledge.pr.watson.org [192.0.2.3]) by fledge.watson.org (8.12.4/8.12.4) with SMTP id gA3J0HOo062829; Sun, 3 Nov 2002 14:00:27 -0500 (EST) (envelope-from robert@fledge.watson.org) Date: Sun, 3 Nov 2002 14:00:16 -0500 (EST) From: Robert Watson X-Sender: robert@fledge.watson.org To: Miguel Mendez Cc: kientzle@acm.org, morganw@chemikals.org, current@FreeBSD.ORG Subject: Re: libc size In-Reply-To: <20021103155858.3be6eda9.flynn@energyhq.homeip.net> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG On Sun, 3 Nov 2002, Miguel Mendez wrote: > > 2) Security. Can LD_LIBRARY_PATH (or other mechanisms) > > be used to deliberately subvert any of these programs? > > (especially the handful of suid/sgid programs here) > .. > > I can't come up right now with an idea of how exploiting LD_LIBRARY_PATH > could be useful with any of these, but the possibility exists. OTOH, the > recently added priviledge elevation feature should make it possible to > have *no* setuid programs on a system, and have the kernel elevate > priviledges for certain syscalls, based on the policy created by > systrace. LD_LIBRARY_PATH is disabled for setuid binaries -- the kernel sets the P_ISSETUGID flag, which is exported to userspace by issetugid(), which is in turn checked by the rtld, which will refuse to observe that environmental variable (and a number of others) as a result. We have plenty of dynamically linked setuid binaires in the system already, and it's not a problem. Robert N M Watson FreeBSD Core Team, TrustedBSD Projects robert@fledge.watson.org Network Associates Laboratories To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message