From owner-freebsd-fs Fri Apr 10 08:15:15 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id IAA24721 for freebsd-fs-outgoing; Fri, 10 Apr 1998 08:15:15 -0700 (PDT) (envelope-from owner-freebsd-fs@FreeBSD.ORG) Received: from fred.muc.de (noidentity@dial018.lrz-muenchen.de [129.187.24.18]) by hub.freebsd.org (8.8.8/8.8.8) with SMTP id IAA24716 for ; Fri, 10 Apr 1998 08:15:12 -0700 (PDT) (envelope-from andi@fred.muc.de) Received: (qmail 2659 invoked by uid 500); 10 Apr 1998 15:14:54 -0000 Message-ID: <19980410171454.39443@fred.muc.de> Date: Fri, 10 Apr 1998 17:14:54 +0200 From: ak@muc.de To: Wolfram Schneider , Andi Kleen Cc: freebsd-fs@FreeBSD.ORG Subject: Re: cvs commit: src/sbin/mount mntopts.h mount.8 mount.c src/sys/kern vfs_lookup.c vfs_syscalls.c vfs_vnops.c src/sys/sys mount.h References: <199804081832.LAA04184@freefall.freebsd.org> <19980410164505.27668@panke.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 0.89.1i In-Reply-To: <19980410164505.27668@panke.de>; from Wolfram Schneider on Fri, Apr 10, 1998 at 04:45:05PM +0200 Sender: owner-freebsd-fs@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org On Fri, Apr 10, 1998 at 04:45:05PM +0200, Wolfram Schneider wrote: > On 1998-04-10 13:41:18 +0200, Andi Kleen wrote: > > > wosch 1998/04/08 11:32:00 PDT > > > Modified files: > > > sbin/mount mntopts.h mount.8 mount.c > > > sys/kern vfs_lookup.c vfs_syscalls.c vfs_vnops.c > > > sys/sys mount.h > > > Log: > > > New mount option nosymfollow. If enabled, the kernel lookup() > > > function will not follow symbolic links on the mounted > > > file system and return EACCES (Permission denied). > > > > Note that this is not enough alone to prevent /tmp races. A malicious > > user can still use a named pipe to feed the victim changed data. > > [moved to freebsd-fs] > > I can add a nonamedpipe option ;-) Or include that with nodev (or does it do that already?) > > A named pipe race is much harder to implement than a symlink race. > How do you avoid dead locks? What deadlocks? the exploit will be "single threaded" but I don't think there are deadlocks. It is possible, that is what counts. Just use O_CREAT|O_EXCL always. -A. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-fs" in the body of the message