[systemd-devel] [RFC 4/8] HACK0: allow meta information customizable

[Daniel Mack]

On 06/27/2014 11:33 AM, Djalal Harouni wrote:
> On Fri, Jun 27, 2014 at 11:24:48AM +0200, Daniel Mack wrote:

>> No, that's what I'm saying. We cannot cache anything as any information
>> may change at any time. The rule here is simple: if you want metadata,
>> you have to be aware that they come at a price. If you don't need them,
>> don't request them :)
> Well, Daniel I think we can do something here!
> 
> We can use the cached metadata from handle or from HELLO and only for
> privileged bus users!
> 
> Privileged bus users can do what ever they want, and per kdbus
> definition this include normal users which is nice! so we can perhap do
> that!

Did you consider the fact that a kdbus handle (the fd) can be passed
from one userspace task to another? Tasks may also modify their name,
drop capabilities, change their effective uid and all the like. Metadata
must match the environment in which the _message_ has been generated,
regardless what was the case when the bus user originally connected to
the bus.

> I've already patches that do this! will send them in minutes, we have
> metadata for free and bechmark improvment hmm say ~50%

Ok.


Thanks,
Daniel