Nicolas/Kyle: > On Fri, Mar 07, 2008 at 02:03:51PM -0500, Kyle McDonald wrote: >> Brian Cameron wrote: >>> Since the lock screen program requires a backend daemon running as >>> root which actually talks to PAM, and since this root daemon should >>> have access to the Xauth keys for each display, it shouldn't be hard >>> to make lockscreen work like this: >>> >>> >> Will the daemon running as root have access to all the xauth keys? >> >> I'm working from memory, but back when I managed a system using NIS+ and >> therefor SecureRPC's for NFS, and the user's homedirs were mounted with >> the -secure option, root couldn't read any of thier files unless they >> were world readable. >> >> Won't that be a problem for this daemon too? > > This can be avoided by putting a copy of the xauth in tmpfs.
I don't think this is an issue, especially if the GDM daemon is used as the backing daemon. Remember the GDM daemon keeps track of all Xauth keys anyway in /var/lib/gdm (or in /var/tmp using GDM 2.21). I believe CDE login keeps the Xauth files cached away somewhere also. These files are only readable by root, but the lock screen daemon would also be running as root, so this shouldn't be an issue. If the background daemon isn't the GDM daemon, it could still access the keys cached by GDM or CDE login (and could be made so it could be easily extended to find cached Xauth files for other display managers). Brian
