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

Leslie M. Barstow III phoenix at
Thu Dec 30 20:44:48 GMT 1999

On Thu, 30 Dec 1999, Steve Langasek wrote:
> On Thu, 30 Dec 1999, Leslie M. Barstow III wrote:

> > BTW - here's a dumb question (kind of related via winbind)
> >       is there an 8-character limitation to the getpwnam()
> >       implementation?  IIRC, at least the passwd file has
> >       this limit (in Linux).

> I'll take questions not tied to holy wars for 200, Alex... :)

> Not a difficult question to answer, though--you say *the* getpwnam()
> implementation, when in fact each Unix has its own implementation.  Some
> Unices have 8-char limits, and in fact attempting to use longer names can
> cause bugs/crashes/exploits.

If Solaris or IRIX are among them, a cross-platform winbind will be
difficult at best.  At least we can start with Linux.

> Linux does not have such a limit, although software running under Linux can
> make poor assumptions about the length of usernames they're given.  When
> looking at files with the 'ls -l' command, the name *displayed* will be
> limited to 8 characters, but this is simply because that's all the name that
> will fit into the 8-character field in the output.

Eww.  Just thinking about this gives me the screaming heebie-jeebies.
20,000 utilities probably assume that, including (but not limited to) tar,
RCS/SCCS - ick.  Projects for the next millenium.


Leslie M. Barstow III  |
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