Security Identifier (SID) to User Identifier (uid) ResolutionSystem

[Luke Kenneth Casson Leighton]

On Thu, 30 Dec 1999, Jeremy Allison wrote:

> Nicolas Williams wrote:

> > Now, I agree that if the only thing Samba needs to do is convert
> > uids/gids to SIDs then using the fileserver's host SID as the base SID
> > and algorythmically converting uids/gids to RIDs of that SID works
> > fine.
> 
> Hurrah, we agree :-).

ok, i picked up on this, earlier.  iwas going to leave it, but i see that
i can't.

i believe nicolas to be assuming that the uid/gids to RIDS mapping
function is capable of dealing with more than one SID, a la microsoft
POSIX / NT algorithm:

draft-lkcl-sidtouid=map-00.txt, section 6.2:
typedef uint32 uid_t;

/* can be used to map a SID to a POSIX uid (32 bit) */
uid_t map_sid_to_uid(SID sid)
{
        uint32 rid;
        uint32 uid_offset = 0x0;
        SID dom_sid;

        /* split a SID into its last RID and the rest, e.g
           S-1-5-21-aaa-bbb-ccc-10001 into
           S-1-5-21-aaa-bbb-ccc and 10001 */
        split_sid(sid, dom_sid, rid);

        /* our own SAM database */
        if (dom_sid == my_sam_sid)
        {
                return (rid & 0xffff);
        }

        /* the SAM of the Domain we are a member of */
        if (is_member_of_domain() && dom_sid == domain_member_sid)
        {
                uid_offset += 0x10000;
                return (rid & 0xffff) + uid_offset;
        }

        /* all other Trusted Domains */
        while ((trusted_domain == gettrustdcsident()) != NULL)
        {
                uid_offset += 0x10000;
                if (dom_sid == trusted_domain)
                {
                        return (rid & 0xffff) + uid_offset;
                }
        }
        return -1; /* oops! */
}