per thread credentials

[Conrad Meyer]

On Fri, Dec 7, 2018 at 2:37 AM Jack Halford <jack at gandi.net> wrote:
>
> hello,
>
> Gandi.net has need of per-thread credentials for a file server. There
> have been prior discussions in a thread[1] in 2009 and also a design[2]
> has been written out on the wiki in 2011. I'm in the process of
> implementing this design.
>...
>
> [1] https://lists.freebsd.org/pipermail/freebsd-arch/2009-May/009300.html
> [2] https://wiki.freebsd.org/Per-Thread%20Credentials

Both of these came out of Isilon.  I think we ended up with special
credential file descriptors, rather than using uid_t's and gid_t's
directly, because of a need for compatibility with arbitrary Windows
LDAP users ("SID"s?) not present in the local id database.

I can't speak to why it didn't land before — I wasn't really around
for that, and there's a 50-50 chance we just didn't want to put in the
effort — but we still use something similar now.  Zach Loafman left
the company long ago and hasn't been an active FreeBSD committer in
quite some time, and ditto mdf at .  Committers at Isilon now are me,
bdrewery@, vangyzen@, dab@, rstone@, and pho@, but none of us are
really involved with what Isilon calls "AIMA" (Authentication,
Identity Management, Authorization).

The APIs we use today look like:

663     AUE_NULL        STD     { int modifytcred2(int fd, \
                                    struct native_token *token, \
                                    int flags); }
664     AUE_NULL        STD     { int modifytcred(int fd1, int fd2, \
                                    int flags); }
665     AUE_NULL        STD     { int accesstcred(char *path, int flags, \
                                    int fd); }
666     AUE_NULL        STD     { int buildtcred(struct native_token *token, \
                                    int current); }
667     AUE_NULL        STD     { int gettcred(char *user, int thread); }
668     AUE_NULL        STD     { int settcred(int fd, int flags, \
                                    struct native_token *token); }
669     AUE_NULL        STD     { int reverttcred(void); }
670     AUE_NULL        STD     { int restricttcred(int fd, struct
native_token *token); }

Best,
Conrad