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 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