mapping uids of file owners to SIDs for AD users

[Steve French]

I was noticing that (at least with richacl) the ownership information
in the ACL is taken from the uid/gid posix ownership information and
therefore the owner SID is displayed as "S-1-22-1..." followed by a
UID rather than querying the UID->SID mapping for that Active
Directory user (the server is joined to the same AD domain as the user
on the Windows client who created the file).  The result of this is
that the owner from Windows explorer looks like

"Unix user\10000" rather than "user at domain" (as it would for Windows to Windows)

looking at uid_to_sid() in passdb/lookup_sid.c it looks like it only
calls out to winbind for this if it doesn't find it in the idmap cache
- how would this work for the common case (e.g. in RHEL) where sssd is
providing the mapping?

-- 
Thanks,

Steve