1/*	$OpenBSD: seteuid.c,v 1.3 2021/12/15 18:42:38 anton Exp $	*/
2/*
3 *	Written by Bret Stephen Lambert <blambert@openbsd.org> 2014
4 *	Public Domain.
5 */
6
7#include <sys/types.h>
8#include <sys/signal.h>
9#include <sys/proc.h>
10#include <sys/sysctl.h>
11#include <sys/wait.h>
12
13#include <err.h>
14#include <stdio.h>
15#include <stdlib.h>
16#include <pwd.h>
17#include <unistd.h>
18
19#include "setuid_regress.h"
20
21int
22main(int argc, const char *argv[])
23{
24	struct kinfo_proc	 kproc;
25	struct passwd		*pw;
26	uid_t			 uid;
27
28	uid = getuid();
29
30	if ((pw = getpwnam(_SETUID_REGRESS_USER)) == NULL)
31		err(1, "unknown user \"%s\"", _SETUID_REGRESS_USER);
32
33	if (seteuid(pw->pw_uid) == -1)
34		err(1, "seteuid 0");
35
36	if (geteuid() != pw->pw_uid)
37		errx(1, "mismatched effective uids");
38
39	checkuids(uid, pw->pw_uid, uid, "seteuid");
40
41	/* should only respond to setuid upon exec */
42	if (issetugid())
43		errx(1, "process incorrectly marked as issetugid()");
44
45	if (read_kproc_pid(&kproc, getpid()) == -1)
46		err(1, "kproc read 0 failed");
47
48	if (!(kproc.p_psflags & PS_SUGID))
49		errx(1, "PS_SUGID not set");
50	if (kproc.p_psflags & PS_SUGIDEXEC)
51		errx(1, "PS_SUGIDEXEC incorrectly set");
52
53	/* at this point, we should be able to reset our uid */
54	if (seteuid(uid) == -1)
55		err(1, "seteuid 1");
56
57	if (read_kproc_pid(&kproc, getpid()) == -1)
58		err(1, "kproc read 1 failed");
59
60	if (!(kproc.p_psflags & PS_SUGID))
61		errx(1, "PS_SUGID not set");
62	if (kproc.p_psflags & PS_SUGIDEXEC)
63		errx(1, "PS_SUGIDEXEC incorrectly set");
64
65	exit(0);
66}
67