Lennart Poettering mzqohf at 0pointer.de
Fri Dec 13 10:17:58 PST 2013

On Fri, 13.12.13 11:39, Serge Hallyn (serge.hallyn at ubuntu.com) wrote:

> Hi,
> dbus-protocol.h defines DBUS_TYPE_UNIX_FD as an iter type which can
> be appended to a message.  Would it be acceptable to add something
> along the lines of DBUS_TYPE_LINUX_CRED ?  Better yet, is there already
> a way of sending a struct ucred as SCM_CREDENTIAL by appending it to
> a dbus message?

You can also query the identity of a bus peer with the bus driver calls
GetConnectionUnixUser and GetConnectionUnixProcessID.

In kdbus you will also get a variety of creds attached to all messages
implicitly (pid, gid, uid, pid_starttime, tid, comm, tid_comm, cmdline,
cgroup, unit, slice, user unit, session, owner uid, eff caps, inh caps,
perm caps, bounding caps, selinux context, audit session, audit login
uid), and this can be selected by the receiver.

> The goal of doing this is not to authenticate the client, but to
> pass pids and uids across namespaces and have the kernel translate
> them.  So the cred sent along with the null byte is akin to what I
> need, but it's not what I need.

I am pretty sure it would be wrong to have something like this as data
type. This data should be appended implicitly, not explicitly.


Lennart Poettering, Red Hat

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