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
21 int
main(int argc,const char * argv[])22 main(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