1/*++
2/* NAME
3/*	set_ugid 3
4/* SUMMARY
5/*	set real, effective and saved user and group attributes
6/* SYNOPSIS
7/*	#include <set_ugid.h>
8/*
9/*	void	set_ugid(uid, gid)
10/*	uid_t	uid;
11/*	gid_t	gid;
12/* DESCRIPTION
13/*	set_ugid() sets the real, effective and saved user and group process
14/*	attributes and updates the process group access list to be just the
15/*	user's primary group. This operation is irreversible.
16/* DIAGNOSTICS
17/*	All system call errors are fatal.
18/* SEE ALSO
19/*	setuid(2), setgid(2), setgroups(2)
20/* LICENSE
21/* .ad
22/* .fi
23/*	The Secure Mailer license must be distributed with this software.
24/* AUTHOR(S)
25/*	Wietse Venema
26/*	IBM T.J. Watson Research
27/*	P.O. Box 704
28/*	Yorktown Heights, NY 10598, USA
29/*--*/
30
31/* System library. */
32
33#include <sys_defs.h>
34#include <unistd.h>
35#include <grp.h>
36#include <errno.h>
37
38/* Utility library. */
39
40#include "msg.h"
41#include "set_ugid.h"
42
43/* set_ugid - set real, effective and saved user and group attributes */
44
45void    set_ugid(uid_t uid, gid_t gid)
46{
47    int     saved_errno = errno;
48
49    if (geteuid() != 0)
50	if (seteuid(0) < 0)
51	    msg_fatal("seteuid(0): %m");
52    if (setgid(gid) < 0)
53	msg_fatal("setgid(%ld): %m", (long) gid);
54    if (setgroups(1, &gid) < 0)
55	msg_fatal("setgroups(1, &%ld): %m", (long) gid);
56    if (setuid(uid) < 0)
57	msg_fatal("setuid(%ld): %m", (long) uid);
58    if (msg_verbose > 1)
59	msg_info("setugid: uid %ld gid %ld", (long) uid, (long) gid);
60    errno = saved_errno;
61}
62