[879] in NetBSD-Development
NetBSD configuration for dialup
daemon@ATHENA.MIT.EDU (Sam Hartman)
Fri Jul 21 17:38:30 1995
Date: Fri, 21 Jul 1995 17:37:35 -0400
From: Sam Hartman <hartmans@MIT.EDU>
To: vug-dialup@MIT.EDU
Cc: pc-dialup@MIT.EDU
Mat ask me to send in these ideas. I believe that this takes
input inadvertantly from Greg, jhawk, and mycroft, although others may
have contributed to the discussions in the SIPB office. Basically,
this deals with ways of securing the dialups.
* First, don't compile BPF devices into the kernel
* Run in security level 2 if possible to avoid people writing to kmem;
this also prevents direct access to disk devices besides mounting
them.
* Consider adapting NetBSD AFS so that it can be linked into the
Kernel instead of treated as a loadable kernel module and disable
LKM's.
* Use imutable files where appropriate. Unfortunately, you'll have
to take the dialup down into single user mode to change these; routine
maintinance may make it difficult for some files like /.klogin to be
immutable. You may also find append-only files useful.
* If physical access to upgrade the kernel isn't objectionable, then
put the kernel on a write-protected floppy, set the CMOS to boot of a
first, to avoid kernel tampering. Charles claims he could probably
find a way around this if he were root, but I doubt many others could,
especially since you cannot load stuff into kernel space or modify
/dev/kmem or /dev/mem.
--Sam
