/dev/{km,m}em worries
rickt@gnu.ai.mit.edu
Tue, 17 May 1994 10:49:05 -0400 (EDT)
Hi folks,
What exactly are the problems with having /dev/mem and /dev/kmem readable
by other? Is there any way in which our systems can be exploited by
this? I recently noticed that one of our (two) servers had a
different perm on the abovementioned files. Cf:
$ rsh janus ls -l /dev/{km,m}em
crw-r----- 1 root 3, 1 Sep 20 1993 /dev/kmem
crw-r----- 1 root 3, 0 Sep 20 1993 /dev/mem
$ rsh isis ls -l /dev/{km,m}em
crw-r--r-- 1 root 3, 1 Sep 3 1992 /dev/kmem
crw-r--r-- 1 root 3, 0 Sep 3 1992 /dev/mem
For the record, isis is a sun4m (two processors) and janus is a sun4c,
both running SunOS 4.1.3. Is there anything I can be watchful of, to make
sure that we haven't been compromised? Can anyone provide me with
information on how to exploit a mismatched perm on mem/kmem (if any)?
/rmt
--
main(v,c)char**c;{for(v[c++]="Rick Tait <rickt@gnu.ai.mit.edu>\n)";(!!c)[*c]
&&(v--||--c&&execlp(*c,*c,c[!!c]+!!c,!c));**c=!c)write(!!*c,*c,!!**c);}