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Re: openid support for f9?



On Thu, Nov 08, 2007 at 01:53:54PM -0500, Simo Sorce wrote:
> Alan, I think we live on diffrent planets then :-)

Quite possibly. I make mine one, two, third one out unless we missed one.

> I deal with ID mappings problems since ever in the Samba world, and I
> rewrote the idmap subsystem twice, please trust me when I say the
> problem is *far* from being solved, for anything but ideal cases which
> do not exist on real networks.

Its a solved problem - I'm not saying its solved in RHEL or for our customerbase
thats a different thing.

> > This doesn't work anyway - a UUID is intended to avoid collisions, it is
> > not intended to be securely unique.
> 
> True, but there is almost no way to get something securely unique, and
> anyway that's absolutely not the point. What we need is exactly to
> avoiding collisions, not securely unique IDs.

You cannot avoid collisions using ids that are defacto publically visible.
I will choose to clash with your ID because I'm bad. 

> > Short of having a DNS like global "phonebook" for UIDs the solvable problem
> > is "can I have access to xyz"
> 
> Exactly, but yet you need to represent identity in term of UIDs and GIDs
> in the POSIX world, hence why I am slowly advocating for *local* mapping
> tables. Network mapping tables simply do not work.

They work very well when the authetication domain and the user domain and
the set of systems overlap - thats actually not that uncomoon. When they don't
you need mapping at that level - be it group or system.

> with a way to store mappings on removable drivers when needed. Think
> agaion of a USB pen drive formatted ext2, you need at least a file where
> you map the UID used on the disk to the identity used (be it an email or
> a kerberos principal or whatever you can think of to represent an
> identity) and for groups too. 

That makes a lot of sense for deciding who is who, its absolutely useless
for authentication purposes. Having a key which says "please sir I'm root"
doesn't solve the trust problem on a network.

How you do the uid mapping is I think not too important. You would want
to load a table of [disk uid][local uid] into a stacking fs or similar and
that can be done by parsing the fs in user space (with a default 'root only'
rights set until its parsed and loaded). Its not quite that simple because
you need to add new user mappings and know what is free. Thats not a trivial
excercise on GFS2 I suspect.

Truth be told however what most people want for removable storage is blanket
ownership by themself.

Alan



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