1 /* $OpenBSD: setresuid_effective_exec.c,v 1.2 2021/12/13 16:56:50 deraadt 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/proc.h> 9 #include <sys/sysctl.h> 10 #include <sys/wait.h> 11 12 #include <err.h> 13 #include <stdio.h> 14 #include <stdlib.h> 15 #include <string.h> 16 #include <pwd.h> 17 #include <unistd.h> 18 19 #include "setuid_regress.h" 20 21 int 22 main(int argc, char *argv[]) 23 { 24 struct kinfo_proc kproc; 25 struct passwd *pw; 26 char *toexec = NULL; 27 uid_t uid; 28 29 if (argc > 1) { 30 argv ++; 31 if ((toexec = strdup(argv[0])) == NULL) 32 err(1, "strdup"); 33 } 34 35 if ((pw = getpwnam(_SETUID_REGRESS_USER)) == NULL) 36 err(1, "unknown user \"%s\"", _SETUID_REGRESS_USER); 37 38 uid = getuid(); 39 40 if (setresuid(-1, pw->pw_uid, -1) == -1) 41 err(1, "setuid"); 42 checkuids(uid, pw->pw_uid, uid, "setuid"); 43 44 /* should only respond to setuid upon exec */ 45 if (issetugid()) 46 errx(1, "process incorrectly as issetugid()"); 47 48 if (read_kproc_pid(&kproc, getpid()) == -1) 49 err(1, "kproc read failed"); 50 51 if (!(kproc.p_psflags & PS_SUGID)) 52 errx(1, "PS_SUGID not set"); 53 if (kproc.p_psflags & PS_SUGIDEXEC) 54 errx(1, "PS_SUGIDEXEC incorrectly set"); 55 56 if (toexec != NULL) 57 if (execv(toexec, argv) == -1) 58 err(1, "exec of %s failed", toexec); 59 free(toexec); 60 61 exit(0); 62 } 63