[rsbac] Problems with UM/RC

Amon Ott ao at rsbac.org
Fri Jul 1 17:21:43 CEST 2005


On Freitag 01 Juli 2005 17:07, Rafal Bisingier wrote:
> I feel a little oddly, but I think I found one more bug in UM code 
of
> RSBAC. Here's the problem:
> I've got a RC role with def_user_create_type set to 3 (I've added 
this
> type to default RSBAC config), but sometimes when a process with 
this
> role try to create user it create a user with rc_type 0 !
> That's not the end of the problem - when I change rc_type of this 
user
> to anything else (eg. 1 - Security User), then I delete this user 
(from
> the secoff account), and once again I create user with the same UID 
by
> the original process (with def_user_create_type = 3), then the newly
> created user will get rc_type set to this UID before deletion.
> But that's still not the worst of it. This recreated user will get 
also
> the same RC role (!) as user with this UID before it was deleted.

You are correct - default_user_create_type does not yet work. The 
notification call is missing from the UM syscalls, so the attribute 
is kept at the value used before.

I am not sure how to handle this anyway, because the user type might 
have been already set for a Linux UM user. If you create a user via 
RSBAC UM, it sounds logical to use this flag. Maybe it should default 
to 'do-not-touch', or we make it optional in RC options. Or optional 
in useradd/userdel.

Amon.
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