Re: [RFC] [PATCH] Replace security fields with hashtable

From: Michael Dean (mdean@private)
Date: Wed Oct 27 2004 - 14:16:18 PDT


what would it be like if we just used xfs and implemented SGI's ACL's.  
Just brainstorming alternative to SE.
Michael

Stephen Smalley wrote:

>On Wed, 2004-10-27 at 14:12, Valdis.Kletnieks@private wrote:
>  
>
>>The point is that in this case, *no* domains are trusted - we don't want
>>end users compiling their Fortran programs to have stuff hijacked out from
>>under them when they build in /tmp.  Similarly, we care about *other* directories
>>as well - /tmp and /var/tmp are just *two* places things live, there's other
>>world-writable directories as well.
>>    
>>
>
>The SELinux policy makes extensive use of derived types for runtime
>files created by domains, and typically doesn't let domains touch each
>others' runtime files.  So I think much of this protection is already
>provided, and remember that the directory isn't truly world writable
>under SELinux unless it is labeled with a type that is world writable
>(in which case odds are good that we've already defined derived types
>for the files created in it that are sensibly isolated).
>
>  
>
>>As another example - how would you implement "don't remove other user's files
>>in a +t directory" in SELinux?  Note that nobody seems to think that *that*
>>semantic isn't sane and desireable - but it's equally hard to state in SELinux,
>>for the same reasons.
>>    
>>
>
>Um, no.  SELinux provides per-file unlink permission, and as with the
>previous discussion, you typically don't get to unlink files with types
>created by other domains.
>
>But this discussion is largely irrelevant, I think.  I'm not opposing a
>simple mechanism for stacking of the LSM security fields; I just don't
>want it to unnecessarily harm the (presently common) single LSM case.  I
>think that is achievable.  Just not via a hashtable implementation.
>
>And for production, I agree that you ultimately want an integrated
>security solution.  I see stacking as primarily a vehicle for easy
>experimentation, not for the final system.
>
>  
>



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