On Thu, 2013-10-24 at 16:08 +0200, Samuel Thibault wrote: > Svante Signell, le Thu 24 Oct 2013 15:38:11 +0200, a écrit :
> > > > + goto label; > > > > > > Why skipping SCM_RIGHTS support? The message may contain *both* > > > SCM_RIGHT and SCM_CREDS, we have to support that. Likewise on the > > > receiver side. > > > > I have never seen any application using that. > > That doesn't mean that we can avoid supporting it. This can easily be changed, if the -nz option is scrapped. > > What about the _hurd_check_ids() call? > > That is a completely different thing: _hurd_check_ids talks with the > auth server of the process, which it trusts. In the patch there is a call to _hurd_check_ids first. > Your code is talking with > proc/auth servers indicated by the sender, which we don't want to trust. The remaining part is, yes. > > > So I'd say a completely different way is needed to check the pid of the > > > sender. The matter here is that only pflocal has a port to the sender, > > > the receiver doesn't have one. Another noticeable thing is that the > > > receiver trusts pflocal, so if pflocal provides information about the > > > sender (such as a task port of the sender), the receiver can trust it, > > > and safely use proc_task2pid etc. to get information about it from its > > > own proc and auth servers. So probably adding something to pflocal can > > > provide a solution. > > > > Can you elaborate? > > I mean something like extending pflocal RPCs, to include the task port > of the sender along the socket_send/recv path. I however don't know how > the pflocal side of S_socket_send can know which task emitted the RPC. > That's probably the main problem to be solved. This in non-trivial, right? Then it's currently over my head. Bad luck. So modifying S_io_reauthenticate used for SCM_CREDS is not workable? > > How to modify proc and auth servers (or write simple code) to fake > > stuff? > > You can for instance simply use the hurdish fakeroot. The fakerooted > process will thoughfully think it's root, and send the port to the faked > auth, and if the receivers asks that auth server, it'll of course say > the fakerooted process is indeed root. Might try this, or give up, we'll see :(
