[TAG] pppd changing file permissions (Was Re: lpr works for user not root in Basiclinux 2.1)

[sindi keesan]

On Tue, 27 Mar 2007, Ben Okopnik wrote:

> On Wed, Mar 28, 2007 at 12:11:51AM +0000, sindi keesan wrote:
>>
>> The man page says +i prevents you from writing data to the file.  I need
>> to write to the device to use the modem or rxvt.  The problem is that it
>> is being reset so the user cannot write to it.
>
> Right - so the initial step would be to "disable" it to see what
> process complains. If it's "pppd" that's causing problems, then that's
> what you'll see in the logs; if it's "rxvt", then that's what'll be
> reported.
>
>> i is immutable
>> u is undeletable
>>
>> Sort of like write protection in DOS?
>
> No - that would be "chmod -w <filename>".

Write protected DOS files cannot be deleted or written to, and +i makes a 
file unwriteable, so there is some overlap.


>> I doubt we have log files.
>
> Then I can only wish you the best of luck in troubleshooting your
> problems. I've never been good at running with both my feet tied in a
> sack.

We have a busybox syslogd - "system logging daemon (says Doctor Linux). 
It accumulates log messages from various applications and stores them into 
log files based on /etc/syslogd.conf" (which I would need to create to 
specify where the log message go).q

The log is used to check for attempts at a breakin.

I have the man page but this is more than I can handle tonight unless you 
want to walk me through the details.

pppd mini-HOWTO  says to chmod 4750 - 4 being suid which would give 
-rwsr-x---

I have -rwsr-xr-- 1 root root (close enough?)

Since rxvt and pppd are suid root it should not matter if ttyp0 and ttyS1 
and ttyLT0 are writeable by user.  Thanks for the explanations. 
I will experiment a bit with pppd permissions.

Sindi

>
> -- 
> * Ben Okopnik * Editor-in-Chief, Linux Gazette * http://LinuxGazette.NET *
>

keesan at sdf.lonestar.org
SDF Public Access UNIX System - http://sdf.lonestar.org