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Re: Sarge sec update: sudo_1.6.8p7-1.3_i386.deb probs



On Sat, Jan 21, 2006 at 06:54:21AM -0600, Hugo Vanwoerkom wrote:
> Simo Kauppi wrote:
> >On Sat, Jan 21, 2006 at 12:03:26PM +0200, Simo Kauppi wrote:
> >>On Fri, Jan 20, 2006 at 03:58:30PM -0600, Hugo Vanwoerkom wrote:
> >>>>On Fri, Jan 20, 2006 at 08:02:33AM -0600, Hugo Vanwoerkom wrote:
> >>>>>Hi,
> >>>>>I just did a security upgrade with Sarge and got installed 
> >>>>>sudo_1.6.8p7-1.3_i386.deb. But when I use sudo to get to synaptic I 
> >>>>>get:
> >>>>>
> >>>>>(synaptic:25937): Gtk-WARNING **: cannot open display:
> >>>Thanks! And a good guess. But what?
> >>>
> >>>And this is in the sudoers manpage:
> >>>
> >>>Lists that can be used in a boolean context:
> >>>
> >>>...
> >>>env_check
> >>>    Environment variables to be removed from the user's environment if 
> >>>the variable's value contains %
> >>>    or /
> >>>    characters. This can be used to guard against printf-style format 
> >>>vulnerabilities in poorly-written programs. The argument may be a 
> >>>double-quoted, space-separated list or a single value without 
> >>>double-quotes. The list can be replaced, added to, deleted from, or 
> >>>disabled by using the =
> >>>    , +=
> >>>    , -=
> >>>    , and !
> >>>    operators respectively. The default list of environment variables 
> >>>to check is printed when sudo is run by root with the -V option.
> >>>...
> >>>
> >>>Sounds like Greek to me. Can anybody tell me what in fact one should 
> >>>specify in sudoers?
> >>>
> >>>Thanks!
> >>>
> >>>H
> >
> >In other words, env_check is a list of variables, whose value is
> >checked, and if they contain a '%' or a '/', they are blocked. So you
> >need to find out which variable is preventing the use, and put
> >env_check -= VARIABLE
> >into the /etc/sudoers, to disable its checking.
> >
> >One good guess would be HOME.
> >
> >The checking should be totally disabled if you put
> >env_check =
> 
> Gets:
> >>> sudoers file: syntax error, line 12 <<<
> sudo: parse error in /etc/sudoers near line 12
> 
> where I put:
> 
> env_check =
> 
> >into the /etc/sudoers file (i am guessing here), but I wouldn't
> >recommend it, as it is a security feature.
> >
> >Simo
> 
> Thanks Simo!
> 
> Needless to say I am a little surprised that this comes about in Stable 
> Sarge without further explanations.
> 
> I filed a bug (349085) which I later retracted and apologized for.
> 
> Stick with sudo_1.6.8p7-1.2_i386.deb folks!
> 
> H

Hi,

Don't give up just yet :)

I just upgraded my sudo and re-read the security announcement and the
manual page.

It seems I interpreted it a little bit wrong...

Check if you have a line
Defaults env_reset
or
Defaults = env_reset
in your /etc/sudoers. If it is, comment it out or change it to
Defaults !env_reset
and try again...

In unstable/etch it is left for the admin to add that line into the
/etc/sudoers. env_reset is actually the parameter, which limits the
environment variables. env_check is then used to add the desired
variables.

And the syntax should be
Defaults env_check += "VARIABLE1 VARIABLE2"

BTW: it is always a good idea to edit the sudoers file with `visudo`,
which also makes the sanity check.

Simo
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