Subject: Re: CRITICAL ** Holes in default cron jobs ** CRITICAL
To: None <current-users@NetBSD.ORG>
From: Michael Richardson <mcr@sandelman.ottawa.on.ca>
List: current-users
Date: 12/30/1996 19:55:02
>>>>> "der" == der Mouse <mouse@Holo.Rodents.Montreal.QC.CA> writes:
>> I'd like to suggest that we generalize the solution by making
>> all the rm commands only remove files owned by root,bin,daemon.
der> I'd assume you mean _not_ remove such files. :-)
Although I have I bad habit of missing negatives, this wasn't one of
them.
I guess it depends.
If you are removing #*, *~ etc, files, then root should only remove
root's files. Perhaps always doing the deletion with the permissions
of the user who'se files they are.
/etc/daily removes the file following things:
/tmp files not accessed in 3 days
/tmp directories not accessed in 1 day
/var/tmp files not accessed in 7 days
/var/tmp directories not accessed in 1 day
/scratch files/dirs 1 day
/var/preserve 7 days
/var/rwho 7 days
/ - lists *.core files
/ - remove [#,]* \
/ - remove .#* |
/ - remove a.out + 3 days no access
/ - remove *.CKP (what is this?) |
/ - remove .emacs_[0-9]* /
It is presumably these files that are at risk of the symlink
bait/switch.
>> All those simply generate a warning to root. Perhaps with a
>> script to do the actual rm squirrelled away somewhere.
By warning, I mean, a message in an emailed report. E.g.
"please remove the following files. You can do so by executing /etc/rootjobs/rm12345"
der> the kernel know what UIDs are "special", which is pretty
der> gross. (It's bad enough having it know about UID 0
der> specially.) And of course it doesn't affect anything but
der> unlink()....
der> To be sure, teaching the kernel about multiple special UIDs
der> is something I've been meaning to do, but in a more general
der> context, not just a special case for unlink().
I wonder if ten well chosen group id's with a default expanded (to
64) group id vector might not deal with a lot of things. E.g. group
"daemon" should be able to bind port <1024. (I am *not* including rsh
usage, just server usage)
:!mcr!: | Network security consulting and
Michael Richardson | contract programming
WWW: mcr@sandelman.ottawa.on.ca. PGP key available.