[9fans] log oversight

[9fans] log oversight

[Jeff Sickel]

I've just built out a new Plan 9 cpu/auth server and noticed that
others are able to write to the logs.  Is this intentional or just an
oversight?


cpu% ls -l /sys/log
a-rw-rw-rw- M 2936 sys    sys          0 Aug  3  2007 /sys/log/6in4
a-rw-rw-rw- M 2936 sys    sys          0 Apr 26  2002 /sys/log/aan
a-rw-rw-rw- M 2936 sys    sys       9644 Mar 15 19:45 /sys/log/auth
a-rw-rw-r-- M 2936 bootes bootes  219734 Mar 15 20:30 /sys/log/cron
a-rw-rw-rw- M 2936 sys    sys          0 May 21  2000 /sys/log/cs
a-rw-rw-rw- M 2936 sys    sys    1273328 Mar 15 20:37 /sys/log/dns
a-rw-rw-rw- M 2936 sys    sys          0 Sep 12  2007 /sys/log/fossil
a-rw-rw-rw- M 2936 sys    sys       1145 Mar  7 14:55 /sys/log/ftp
d-rwxrwxr-x M 2936 sys    sys          0 Feb 28 13:32 /sys/log/httpd
a-rw-rw-rw- M 2936 sys    sys          0 May 21  2000 /sys/log/imap4d
a-rw-rw-rw- M 2936 sys    sys          0 May 21  2000 /sys/log/ipboot
a-rw-rw-rw- M 2936 sys    sys          0 Jul 31  2007 /sys/log/ipconfig
a-rw-rw-rw- M 2936 sys    sys      29713 Mar 13 01:46 /sys/log/listen
a-rw-rw-rw- M 2936 sys    sys        914 Sep 12  2007 /sys/log/mail
a-rw-rw-rw- M 2936 sys    sys          0 May 21  2000 /sys/log/nfs
a-rw-rw-rw- M 2936 sys    sys          0 May 21  2000 /sys/log/nfsserver
a-rw-rw-rw- M 2936 sys    sys          0 May 21  2000 /sys/log/pop3
a-rw-rw-rw- M 2936 sys    sys          0 May 21  2000 /sys/log/
portmapper
a-rw-rw-rw- M 2936 sys    sys          0 May 21  2000 /sys/log/ppp
a-rw-rw-rw- M 2936 sys    sys          0 May 21  2000 /sys/log/pptpd
a-rw-rw-rw- M 2936 sys    sys        182 Mar 24  2004 /sys/log/runq
a-rw-rw-rw- M 2936 sys    sys          0 Jan  5  2005 /sys/log/secstore
a-rw-rw-rw- M 2936 sys    sys         69 Mar 24  2004 /sys/log/smtp
a-rw-rw-rw- M 2936 sys    sys          0 May 21  2000 /sys/log/smtp.fail
a-rw-rw-rw- M 2936 sys    sys       1032 Mar 13 06:56 /sys/log/smtpd
a-rw-rw-rw- M 2936 sys    sys          0 Oct 29  2004 /sys/log/smtpd.mx
a-rw-rw-rw- M 2936 sys    sys       4965 Mar 14 10:24 /sys/log/ssh
a-rw-rw-rw- M 2936 sys    sys          0 May 21  2000 /sys/log/telnet
a-rw-rw-rw- M 2936 sys    sys       1764 Mar  8 12:57 /sys/log/timesync
d-rwxrwxr-x M 2936 sys    sys          0 Feb 28 13:32 /sys/log/
timesync.d
a-rw-rw-rw- M 2936 sys    sys          0 Jul 31  2007 /sys/log/
v6routeradv

Re: [9fans] log oversight

[balaji]

intentional. if you do a ls -ltm, you will see [none] would have
updated smtp*, runq etc...
upas/*, others run as none, and well...

is it a shortcoming compared to unix world? these logs
are not sacrosanct.

On Sun, Mar 15, 2009 at 6:49 PM, Jeff Sickel <jas@corpus-callosum.com> wrote:
> I've just built out a new Plan 9 cpu/auth server and noticed that others are
> able to write to the logs.  Is this intentional or just an oversight?
>
>
> cpu% ls -l /sys/log
> a-rw-rw-rw- M 2936 sys    sys          0 Aug  3  2007 /sys/log/6in4
> a-rw-rw-rw- M 2936 sys    sys          0 Apr 26  2002 /sys/log/aan
> a-rw-rw-rw- M 2936 sys    sys       9644 Mar 15 19:45 /sys/log/auth
> a-rw-rw-r-- M 2936 bootes bootes  219734 Mar 15 20:30 /sys/log/cron
> a-rw-rw-rw- M 2936 sys    sys          0 May 21  2000 /sys/log/cs
> a-rw-rw-rw- M 2936 sys    sys    1273328 Mar 15 20:37 /sys/log/dns
> a-rw-rw-rw- M 2936 sys    sys          0 Sep 12  2007 /sys/log/fossil
> a-rw-rw-rw- M 2936 sys    sys       1145 Mar  7 14:55 /sys/log/ftp
> d-rwxrwxr-x M 2936 sys    sys          0 Feb 28 13:32 /sys/log/httpd
> a-rw-rw-rw- M 2936 sys    sys          0 May 21  2000 /sys/log/imap4d
> a-rw-rw-rw- M 2936 sys    sys          0 May 21  2000 /sys/log/ipboot
> a-rw-rw-rw- M 2936 sys    sys          0 Jul 31  2007 /sys/log/ipconfig
> a-rw-rw-rw- M 2936 sys    sys      29713 Mar 13 01:46 /sys/log/listen
> a-rw-rw-rw- M 2936 sys    sys        914 Sep 12  2007 /sys/log/mail
> a-rw-rw-rw- M 2936 sys    sys          0 May 21  2000 /sys/log/nfs
> a-rw-rw-rw- M 2936 sys    sys          0 May 21  2000 /sys/log/nfsserver
> a-rw-rw-rw- M 2936 sys    sys          0 May 21  2000 /sys/log/pop3
> a-rw-rw-rw- M 2936 sys    sys          0 May 21  2000 /sys/log/portmapper
> a-rw-rw-rw- M 2936 sys    sys          0 May 21  2000 /sys/log/ppp
> a-rw-rw-rw- M 2936 sys    sys          0 May 21  2000 /sys/log/pptpd
> a-rw-rw-rw- M 2936 sys    sys        182 Mar 24  2004 /sys/log/runq
> a-rw-rw-rw- M 2936 sys    sys          0 Jan  5  2005 /sys/log/secstore
> a-rw-rw-rw- M 2936 sys    sys         69 Mar 24  2004 /sys/log/smtp
> a-rw-rw-rw- M 2936 sys    sys          0 May 21  2000 /sys/log/smtp.fail
> a-rw-rw-rw- M 2936 sys    sys       1032 Mar 13 06:56 /sys/log/smtpd
> a-rw-rw-rw- M 2936 sys    sys          0 Oct 29  2004 /sys/log/smtpd.mx
> a-rw-rw-rw- M 2936 sys    sys       4965 Mar 14 10:24 /sys/log/ssh
> a-rw-rw-rw- M 2936 sys    sys          0 May 21  2000 /sys/log/telnet
> a-rw-rw-rw- M 2936 sys    sys       1764 Mar  8 12:57 /sys/log/timesync
> d-rwxrwxr-x M 2936 sys    sys          0 Feb 28 13:32 /sys/log/timesync.d
> a-rw-rw-rw- M 2936 sys    sys          0 Jul 31  2007 /sys/log/v6routeradv
>
>
>
>

Re: [9fans] log oversight

[erik quanstrom]

> is it a shortcoming compared to unix world? these logs
> are not sacrosanct.
>

linux typically uses log daemons to do the actual logging.
unless they are encrypting all those channels, even from
untrusted agents like smtp daemons, i don't know how you
provide better security.  actually plan 9 has one big advantage:
the append-only flag.  the worst a rogue agent can do is
waste disk space.

the plan 9 solution isn't perfect, but a better solution would
be many times more complex.

- erik

Re: [9fans] log oversight

[ron minnich]

note that those files are append-only.

logs on unix are writeable by everyone:
[rminnich@Panzer ~]$ logger -p kern.err "JUNK"
[rminnich@Panzer ~]$ sudo tail -f /var/log/messages

Mar 16 04:15:03 Panzer rminnich: JUNK


ron

Re: [9fans] log oversight

[J.R. Mauro]

On Sun, Mar 15, 2009 at 11:18 PM, ron minnich <rminnich@gmail.com> wrote:
> note that those files are append-only.
>
> logs on unix are writeable by everyone:
> [rminnich@Panzer ~]$ logger -p kern.err "JUNK"
> [rminnich@Panzer ~]$ sudo tail -f /var/log/messages
>
> Mar 16 04:15:03 Panzer rminnich: JUNK
>

This didn't work on my linux box. I actually have:

% ls -l /var/log/messages
-rw------- 1 root root 960355 2009-03-15 23:51 /var/log/messages

>
> ron
>
>

Re: [9fans] log oversight

[Nathaniel W Filardo]

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On Sun, Mar 15, 2009 at 08:49:50PM -0500, Jeff Sickel wrote:
> I've just built out a new Plan 9 cpu/auth server and noticed that others 
> are able to write to the logs.  Is this intentional or just an  
> oversight?

It is intentional, AFAIK.

An alternative for the paranoid perhaps would be to make an additional fs
(in fossil) containing the log files.  This fs could be set to accept only
the hostowner's credentials for attach requests.  The hostowner, meanwhile,
when constructing namespaces, could bind the right file(s) into the log
directory.  I haven't thought it through in more detail than that, but if I
were to engineer a replacement, that's how I'd start.  HTH.

--nwf;

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Re: [9fans] log oversight

[Alex Efros]

Hi!

On Sun, Mar 15, 2009 at 11:55:39PM -0400, J.R. Mauro wrote:
> > logs on unix are writeable by everyone:
> > [rminnich@Panzer ~]$ logger -p kern.err "JUNK"
> > [rminnich@Panzer ~]$ sudo tail -f /var/log/messages
> This didn't work on my linux box. I actually have:
> % ls -l /var/log/messages
> -rw------- 1 root root 960355 2009-03-15 23:51 /var/log/messages

[OT]
Actually, logger works using /dev/log:

  # ls -l /dev/log
  srwxrwxrwx 1 root root 0 Мар 13 18:55 /dev/log

After chmod 0700 /dev/log users will not be able to use logger anymore.

I usually have all services output logs to stdout (or fifo) and pipe them to
special logging tools like multilog or svlogd, which in turn run as user 'log'
and all these logs have permissions like:

  # ls -ld /var/log/apache2/access{,/current}
  drwxr-s--- 2 log root   4096 Mar 15 03:55 /var/log/apache2/access
  -rw-r--r-- 1 log root 688994 Mar 16 06:11 /var/log/apache2/access/current

So, 'logs on unix' are very configurable and it's not correct to say they
are 'writeable by everyone'. There even no such thing as 'out of box'
setup in unix because it not designed to work 'out of box' and expect some
manual configuration first, :) also, for example, in linux there too many
distributions with different 'out of box' configurations - apache logs
configuration shown above is my 'out of box' configuration installed
automatically while installing Gentoo on new server using my portage overlay.
[/OT]


Back to original question - I think append only is 'good, but not enough'
for logs: adding fake records may hurt no less than mangling existing records.
Reading logs by unauthorized user also may be dangerous.
To solve these two issues you have to set log permissions similar to my
example above: nobody read and only root and log service able to write.
After that it become much less important is these logs are append-only or not
(if one really want to make logs append-only - use chattr +a).

--
			WBR, Alex.

Re: [9fans] log oversight

[Jeff Sickel]

ah, not all are append only...

cpu% ls -lm /sys/log/httpd/clf
[jas] --rw-rw-rw- M 2936 sys sys 0 Mar 15 20:41 /sys/log/httpd/clf


As for paranoia--just more proof I need to stop mucking w/ Linux and
read more of the Plan 9 docs again.

-jas

Re: [9fans] log oversight

[ron minnich]

On Sun, Mar 15, 2009 at 8:55 PM, J.R. Mauro <jrm8005@gmail.com> wrote:
> On Sun, Mar 15, 2009 at 11:18 PM, ron minnich <rminnich@gmail.com> wrote:
>> note that those files are append-only.
>>
>> logs on unix are writeable by everyone:
>> [rminnich@Panzer ~]$ logger -p kern.err "JUNK"
>> [rminnich@Panzer ~]$ sudo tail -f /var/log/messages
>>
>> Mar 16 04:15:03 Panzer rminnich: JUNK
>>
>
> This didn't work on my linux box. I actually have:
>
> % ls -l /var/log/messages
> -rw------- 1 root root 960355 2009-03-15 23:51 /var/log/messages
>


what didn't work? did you try the logger command?

ron

Re: [9fans] log oversight

[erik quanstrom]

> An alternative for the paranoid perhaps would be to make an additional fs
> (in fossil) containing the log files.  This fs could be set to accept only
> the hostowner's credentials for attach requests.  The hostowner, meanwhile,
> when constructing namespaces, could bind the right file(s) into the log
> directory.  I haven't thought it through in more detail than that, but if I
> were to engineer a replacement, that's how I'd start.  HTH.

this would give you exactly the same security behavior as we currently have,
but if the fd were ever closed or dup(2)'d over, syslog(2) would
stop working.

- erik

Re: [9fans] log oversight

[J.R. Mauro]

On Mon, Mar 16, 2009 at 2:30 AM, ron minnich <rminnich@gmail.com> wrote:
> On Sun, Mar 15, 2009 at 8:55 PM, J.R. Mauro <jrm8005@gmail.com> wrote:
>> On Sun, Mar 15, 2009 at 11:18 PM, ron minnich <rminnich@gmail.com> wrote:
>>> note that those files are append-only.
>>>
>>> logs on unix are writeable by everyone:
>>> [rminnich@Panzer ~]$ logger -p kern.err "JUNK"
>>> [rminnich@Panzer ~]$ sudo tail -f /var/log/messages
>>>
>>> Mar 16 04:15:03 Panzer rminnich: JUNK
>>>
>>
>> This didn't work on my linux box. I actually have:
>>
>> % ls -l /var/log/messages
>> -rw------- 1 root root 960355 2009-03-15 23:51 /var/log/messages
>>
>
>
> what didn't work? did you try the logger command?
>

Yep. Nothing happened to the logs.

> ron
>
>