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/* $OpenBSD: setuid_child.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;
pid_t pid;
int status;
if ((pw = getpwnam(_SETUID_REGRESS_USER)) == NULL)
err(1, "unknown user \"%s\"", _SETUID_REGRESS_USER);
if (setuid(pw->pw_uid) == -1)
err(1, "setuid");
switch ((pid = fork())) {
default:
waitpid(pid, &status, 0);
if (WIFSIGNALED(status))
errx(1, "child exited due to signal %d",
WTERMSIG(status));
else if (WEXITSTATUS(status) != 0)
errx(1, "child exited with status %d",
WEXITSTATUS(status));
break;
case 0:
/*
* From the setuid man page:
* The setuid() function sets the real and effective user IDs
* and the saved set-user-ID of the current process
*/
checkuids(pw->pw_uid, pw->pw_uid, pw->pw_uid, "setuid child");
/* should only respond to setuid upon exec */
if (issetugid())
errx(1, "child 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");
break;
case -1:
err(1, "fork");
/* NOTREACHED */
}
exit(0);
}
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