[redhat-lspp] Re: MLS enforcing PTYs, sshd, and newrole

[James Antill]

On Wed, 2006-10-25 at 09:59 -0400, Stephen Smalley wrote:
> On Wed, 2006-10-25 at 09:50 -0400, James Antill wrote:
> >  My understanding is that while security_check_context() allows it, the
> > setexeccon() will fail. Which seemed to be good enough.
> 
> No, it won't.  Suppose that I have two Linux users A and B, with A
> authorized for category c0 and B authorized for category c2 in seusers,
> but both A and B are mapped to SELinux user U who is authorized for all
> categories in the kernel policy.  The login-style programs are naturally
> going to be authorized to transition to any of those contexts since they
> have to deal with user logins at any level, so the setexeccon() will
> succeed.  The SELinux security context will have U as the user identity,
> so it will always be valid.  You need an explicit check.

 Ok, I had assumed that "U" would always be different in this case. I
think this update to the patch solves the problem ... it gets the list
of valid roles/levels from get_ordered_context_list() (which I think is
complete, but I'm not 100%) and compares what is entered against that.
 I'm not 100% sure this is right (it means there would be huge lists
returned for MCS, no?), but I don't see what else I can call that would
validate the role/level-range for a specific login.

-- 
James Antill - <james.antill at redhat.com>
setsockopt(fd, IPPROTO_TCP, TCP_CONGESTION, ...);
setsockopt(fd, IPPROTO_TCP, TCP_DEFER_ACCEPT, ...);
setsockopt(fd, SOL_SOCKET,  SO_ATTACH_FILTER, ...);

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