[OLPC Security] Activity home dirs (was Re: OLPC XO Opera browser as Sugar activity)

[Bert Freudenberg]

Am 26.06.2008 um 01:22 schrieb John Gilmore:

>> The activity start script should configure Opera to put its
>> configuration file in $SUGAR_ACTIVITY_ROOT/data instead of
>> $HOME/.opera. Also it should set umask to 0002 so the config file is
>> group-writable (otherwise the next activity instance cannot  
>> overwrite).
>>
>> See http://wiki.laptop.org/go/Low-level_Activity_API#File_Access
>
>>> QSettings: error creating /home/olpc/isolation/1/uid_to_home_dir/
>>> 10000/.qt
>>> opera: Can not use personal directory: /home/olpc/isolation/1/
>>> uid_to_home_dir/10000/.opera
>
> This looks more like a bug in Rainbow than in Opera.
>
> Why would Sugar or Rainbow be setting $HOME to a rainbow-created
> directory that the activity can't make subdirectories in?
>
> (The universe of Unix programs isn't going to rewrite itself because
> OLPC decided that $SUGAR_ACTIVITY_ROOT is the right place to keep your
> files on Unix.  $HOME has been that place for decades.  Rainbow is
> already setting $HOME.  It's just apparently setting it to something
> that doesn't work.)
>
>> Also it should set umask to 0002 so the config file is
>> group-writable (otherwise the next activity instance cannot  
>> overwrite).
>
> If Rainbow runs the same activity as many different UIDs that share a
> single group ID, then yes, Rainbow should be setting the umask so that
> files are created group-writeable by default.  There should be no need
> to modify ordinary Unix programs for this.


Agreed, but Peter's question was about build 708 so it might be fixed  
in the mean time. Indeed I remember discussion about that, although I  
can't find the Trac report. I recall that HOME is set to  
$SUGAR_ACTIVITY_ROOT/instance now, which should work at least, but I  
think is also wrong as it is not shared between activity instances.  
The right place would be $SUGAR_ACTIVITY_ROOT/data. And I think umask  
is set by Sugar nowadays.

But that won't help machines in the field now so I gave a recipe that  
would work around that bug.

- Bert -