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/* $OpenBSD: setresuid.c,v 1.3 2021/12/15 18:42:38 anton Exp $ */
/*
* Written by Bret Stephen Lambert <blambert@openbsd.org> 2014
* Public Domain.
*/
#include <sys/types.h>
#include <sys/signal.h>
#include <sys/proc.h>
#include <sys/sysctl.h>
#include <sys/wait.h>
#include <err.h>
#include <stdio.h>
#include <stdlib.h>
#include <pwd.h>
#include <unistd.h>
#include "setuid_regress.h"
int
main(int argc, const char *argv[])
{
struct kinfo_proc kproc;
struct passwd *pw;
uid_t uid;
if ((pw = getpwnam(_SETUID_REGRESS_USER)) == NULL)
err(1, "unknown user \"%s\"", _SETUID_REGRESS_USER);
uid = getuid();
if (setresuid(pw->pw_uid, -1, -1) == -1)
err(1, "setuid 0");
checkuids(pw->pw_uid, uid, uid, "0");
/* should only respond to setuid upon exec */
if (issetugid())
errx(1, "process incorrectly marked as issetugid()");
if (read_kproc_pid(&kproc, getpid()) == -1)
err(1, "kproc read failed");
if (!(kproc.p_psflags & PS_SUGID))
errx(1, "PS_SUGID not set");
if (kproc.p_psflags & PS_SUGIDEXEC)
errx(1, "PS_SUGIDEXEC incorrectly set");
/* we should be able to roll back our uids for now */
if (setresuid(uid, -1, -1) == -1)
err(1, "setuid 1");
checkuids(uid, uid, uid, "1");
if (setresuid(-1, pw->pw_uid, -1) == -1)
err(1, "setuid 2");
checkuids(uid, pw->pw_uid, uid, "2");
/* we should be able to roll back our uids for now */
if (setresuid(-1, uid, -1) == -1)
err(1, "setuid 3");
checkuids(uid, uid, uid, "3");
/*
* after changing our saved uid, we should be able to change
* our real and effective uids to that of our saved uid,
* but not to anything else
*/
if (setresuid(-1, -1, pw->pw_uid) == -1)
err(1, "setuid 4");
checkuids(uid, uid, pw->pw_uid, "4");
if (setresuid(pw->pw_uid, -1, -1) == -1)
err(1, "setuid 5");
checkuids(pw->pw_uid, uid, pw->pw_uid, "5");
if (setresuid(-1, pw->pw_uid, -1) == -1)
err(1, "setuid 6");
checkuids(pw->pw_uid, pw->pw_uid, pw->pw_uid, "6");
if (setresuid(uid, -1, -1) != -1)
errx(1, "incorrectly capable of setting real uid");
checkuids(pw->pw_uid, pw->pw_uid, pw->pw_uid, "7");
if (setresuid(-1, uid, -1) != -1)
errx(1, "incorrectly capable of setting effective uid");
checkuids(pw->pw_uid, pw->pw_uid, pw->pw_uid, "9");
if (setresuid(-1, -1, uid) != -1)
errx(1, "incorrectly capable of setting saved uid");
checkuids(pw->pw_uid, pw->pw_uid, pw->pw_uid, "9");
/* sanity-check use of -1 as noop */
if (setresuid(-1, -1, -1) == -1)
errx(1, "-1 not properly recognized as noop");
checkuids(pw->pw_uid, pw->pw_uid, pw->pw_uid, "9");
exit(0);
}
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