[rsbac] new features

Andrea Pasquinucci cesare at ucci.it
Tue Nov 2 14:43:38 CET 2004


I have a proposal for a couple of new small features, they are not so 
clear in my mind, so please see if they could be useful or not. Actually 
I believe that it is possible to obtain similar results by using normal 
tools, but the way I think could be easier.

I would like to add a couple of kernel parameters like:

- rsbac_softmode_noback
  this will be like rsbac_softmode, that is boot in softmode, but once
  softmode has been turned off, it cannot be turned on again for the 
  uptime of the machine

- rsbac_secoff_disabled 
  this is probably more tricky, any RSBAC configuration should be 
  disallowed in secure mode, tools and /proc could be read_only but not 
  allow to change any RSBAC configuration, moreover this should apply 
  only when softmode is off, when softmode is on secoff should work as 

Notice that the functionality of the two parameters overlaps, if you use 
the second you do not need the first. Indeed if you boot with

   linux rsbac_softmode rsbac_secoff_disabled

as soon as in the boot scripts you switch off softmode, you cannot 
switch it on again because all RSBAC tools do not work anymore. But if I 
need to do maintenance of the machine, I just boot without the 
rsbac_secoff_disabled parameter. This allows me to protect
lilo.conf/grub.conf read_only with RSBAC and be sure that I can do 
maintenance only from the console.

The rsbac_softmode_noback is a soft version of the second, in this case
I can use the rsbac admin tools, except for "switch softmode on", this
can allow to mantain a remote server in such a way that softmode can be
allowed only with a reboot (first make lilo.conf/grub.conf writable with
the RSBAC admin tools, then change lilo.conf/grub.conf, then reboot). I
guess that a similar effect can be obtained with a careful
configuration, but I fear that in most conditions secoff would be able
to reverse the configuration and allow itself to switch softmode on
without reboot, since the kernel has softmode configured in.

Notice that in both cases I am considering machines which for some 
reasons must boot in softmode.

Please let me know if I can obtained similar behaviour with what there 
is already, or if there are kernel parameters which can give the same 


PS. Where can I find the complete current list of kernel parameters
without need of reading the source ?

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