1 /* $OpenBSD: setegid.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 gid_t gid;
27
28 gid = getgid();
29
30 if ((pw = getpwnam(_SETUID_REGRESS_USER)) == NULL)
31 err(1, "unknown user \"%s\"", _SETUID_REGRESS_USER);
32
33 if (setegid(pw->pw_gid) == -1)
34 err(1, "setegid 0");
35
36 if (getegid() != pw->pw_gid)
37 errx(1, "mismatched effective gids");
38
39 /* should only respond to setuid upon exec */
40 if (issetugid())
41 errx(1, "process incorrectly marked as issetugid()");
42
43 if (read_kproc_pid(&kproc, getpid()) == -1)
44 err(1, "kproc read 0 failed");
45
46 if (!(kproc.p_psflags & PS_SUGID))
47 errx(1, "PS_SUGID not set");
48 if (kproc.p_psflags & PS_SUGIDEXEC)
49 errx(1, "PS_SUGIDEXEC incorrectly set");
50
51 /* at this point, we should be able to reset our gid */
52 if (setegid(gid) == -1)
53 err(1, "setegid 1");
54
55 if (read_kproc_pid(&kproc, getpid()) == -1)
56 err(1, "kproc read 0 failed");
57
58 if (!(kproc.p_psflags & PS_SUGID))
59 errx(1, "PS_SUGID not set");
60 if (kproc.p_psflags & PS_SUGIDEXEC)
61 errx(1, "PS_SUGIDEXEC incorrectly set");
62
63 exit(0);
64 }
65