1/*
2 * Copyright (C) 2015 The Android Open Source Project
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *  * Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 *  * Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in
12 *    the documentation and/or other materials provided with the
13 *    distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#include <assert.h>
30#include <errno.h>
31#include <stddef.h>
32#include <stdlib.h>
33#include <string.h>
34#include <sys/auxv.h>
35#include <sys/cdefs.h>
36
37#include <async_safe/log.h>
38
39#include "private/bionic_arc4random.h"
40#include "private/bionic_globals.h"
41#include "private/KernelArgumentBlock.h"
42
43void __libc_init_setjmp_cookie(libc_globals* globals, KernelArgumentBlock& args) {
44  long value;
45  __libc_safe_arc4random_buf(&value, sizeof(value), args);
46
47  // Mask off the last bit to store the signal flag.
48  globals->setjmp_cookie = value & ~1;
49}
50
51extern "C" __LIBC_HIDDEN__ long __bionic_setjmp_cookie_get(long sigflag) {
52  if (sigflag & ~1) {
53    async_safe_fatal("unexpected sigflag value: %ld", sigflag);
54  }
55
56  return __libc_globals->setjmp_cookie | sigflag;
57}
58
59// Aborts if cookie doesn't match, returns the signal flag otherwise.
60extern "C" __LIBC_HIDDEN__ long __bionic_setjmp_cookie_check(long cookie) {
61  if (__libc_globals->setjmp_cookie != (cookie & ~1)) {
62    async_safe_fatal("setjmp cookie mismatch");
63  }
64
65  return cookie & 1;
66}
67
68extern "C" __LIBC_HIDDEN__ long __bionic_setjmp_checksum_mismatch() {
69  async_safe_fatal("setjmp checksum mismatch");
70}
71