Re: [9fans] p9p/linux factotum port

["Ashwin Ganti" <ashwin.ganti@gmail.com>]

On Tue, May 6, 2008 at 1:22 PM, Enrico Weigelt <weigelt@metux.de> wrote:
> * a@9srv.net <a@9srv.net> wrote:
>
>  > http://plan9.bell-labs.com/iwp9/papers/13.p9auth.pdf
>
>  cool, I wasn't aware of this. never ever seen a patch for
>  the cap devices. does anyone have link ?

The device driver is in:
http://gsoc.cat-v.org/hg/lincapdevice/

The authentication server port is in:
http://gsoc.cat-v.org/hg/p9pauthsrv/
Although I still have to work on some feedback from Russ to get it
polished so that it can be made part of p9p.

>
>  My decision for the *uid files (instead of cap devices) was
>  because:
>
>  a) more flexibilty (not only limited to factotum stuff)
>  b) the kernel doesn't know of usernames.
That is one of the future improvements that I had listed in the paper.
"It would also be nice to have a user space mapping daemon that maps
the string user names and the integer
user ids. This daemon would be contacted by the kernel to resolve the
user names it
gets after parsing the capabilities written to the device files (by the
process and the host
owner's factotum)". I think NFS solves this in a similar way?

For the port I worked around by adding usernames as string equivalents
of uids (like "1001") which is ugly but can be avoided with this
daemon.
Check out the paper for details.

>
>  So, IMHO, the cap handling should be done in userland.

Well, I feel it is more secure to have the kernel manage the
capabilities and do the actual identity change. We trust the kernel
(it is part of the TCB)

>
>
>
>
>  cu
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