From owner-freebsd-security Wed Aug 18 17:22:36 1999 Delivered-To: freebsd-security@freebsd.org Received: from eunice.vinton.com (eunice-out.vinton.com [204.202.33.15]) by hub.freebsd.org (Postfix) with ESMTP id E212314C24 for ; Wed, 18 Aug 1999 17:22:34 -0700 (PDT) (envelope-from jrozes+935022158.3658973423@vinton.com) Received: from molloy.vinton.com (molloy.vinton.com [204.202.33.3]) by eunice.vinton.com (8.8.8/8.8.7) with ESMTP id RAA07765; Wed, 18 Aug 1999 17:22:38 -0700 (PDT) Received: (from jrozes@localhost) by molloy.vinton.com (8.8.8/8.8.8) id RAA00952; Wed, 18 Aug 1999 17:22:38 -0700 (PDT) X-Authentication-Warning: molloy.vinton.com: jrozes set sender to jrozes+935022158.3658973423@vinton.com using -f Date: Wed, 18 Aug 1999 17:22:36 -0700 (PDT) From: Jonathan Rozes Reply-To: Jonathan Rozes To: Barrett Richardson Cc: Mike Tancsa , freebsd-security@FreeBSD.ORG Subject: Re: Any work around for this FreeBSD bug/DoS ? In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-security@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org On Wed, 18 Aug 1999, Barrett Richardson wrote: > Indeed true, but not a problem. Require scripts to have the flag also, > and hack perl to check for the flag for scripts passed on the command > line. That's not enough to 'fix' perl. You'll also need to take away from perl the ability to use the '-e' switch and the ability to read from stdin. If you want to be really pedantic, you could also force taint checking for all scripts, regardless of whether they want it or not. I started to implement something like this for OpenBSD, using the regular filesystem immutable flag on binaries, but stopped when I kept thinking of new ways for a determined attacker to bypass it. In the end, I just arranged things such that all filesystems with directories writable by non-root users were mounted noexec. > Additionally I put a small hack into ld-elf.so.1 so that everything gets > the same level of trust as a suid executable as far as LD_LIBRARY_PATH > is concerned. Why use shared libraries at all on a security-critical system? Cheers, jonathan +++ Jonathan Rozes, System Administrator, Will Vinton Studios To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-security" in the body of the message