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/* Copyright (C) 2014-2025 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <errno.h>
#include <pthread.h>
#include <signal.h>
#include <stdbool.h>
#include <stdio.h>
#include <support/xthread.h>
#include <sys/syscall.h>
#include <unistd.h>
/* Check that a partial setuid failure aborts the process. */
static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
static pthread_cond_t cond_send;
static void (*func_sent) (void);
static pthread_cond_t cond_recv;
#define FAIL(fmt, ...) \
do { printf ("FAIL: " fmt "\n", __VA_ARGS__); _exit (1); } while (0)
static void *
thread_func (void *ctx __attribute__ ((unused)))
{
xpthread_mutex_lock (&mutex);
while (true)
{
if (func_sent != NULL)
{
void (*func) (void) = func_sent;
xpthread_mutex_unlock (&mutex);
func ();
xpthread_mutex_lock (&mutex);
func_sent = NULL;
xpthread_cond_signal (&cond_recv);
}
xpthread_cond_wait (&cond_send, &mutex);
}
return NULL;
}
static void
run_on_thread (void (*func) (void))
{
xpthread_mutex_lock (&mutex);
func_sent = func;
xpthread_mutex_unlock (&mutex);
xpthread_cond_signal (&cond_send);
xpthread_mutex_lock (&mutex);
while (func_sent != NULL)
{
xpthread_cond_wait (&cond_recv, &mutex);
}
xpthread_mutex_unlock (&mutex);
}
static void
change_thread_ids (void)
{
#ifdef __NR_setresuid32
/* Prefer 32-bit setresuid32 over 16-bit setresuid. */
long ret = syscall (__NR_setresuid32, 2001, 2002, 2003);
#else
long ret = syscall (__NR_setresuid, 2001, 2002, 2003);
#endif
if (ret != 0)
FAIL ("setresuid (2001, 2002, 2003): %ld", ret);
}
static uid_t ruid, euid, suid;
static void
get_thread_ids (void)
{
if (getresuid (&ruid, &euid, &suid) < 0)
FAIL ("getresuid: %m (%d)", errno);
}
static void
abort_expected (int signal __attribute__ ((unused)))
{
_exit (0);
}
static int
do_test (void)
{
pthread_t thread;
int ret = pthread_create (&thread, NULL, thread_func, NULL);
if (ret != 0)
FAIL ("pthread_create: %d", ret);
run_on_thread (change_thread_ids);
signal (SIGABRT, &abort_expected);
/* This should abort the process. */
if (setresuid (1001, 1002, 1003) < 0)
FAIL ("setresuid: %m (%d)", errno);
signal (SIGABRT, SIG_DFL);
/* If we get here, check that the kernel did the right thing. */
run_on_thread (get_thread_ids);
if (ruid != 1001 || euid != 1002 || suid != 1003)
FAIL ("unexpected UIDs after setuid: %ld, %ld, %ld",
(long) ruid, (long) euid, (long) suid);
return 0;
}
#include <support/test-driver.c>
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