1/*
2 * Copyright (C) 2012 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#undef _FORTIFY_SOURCE
30
31#include <stdio.h>
32#include <stdlib.h>
33#include <stdarg.h>
34#include "private/libc_logging.h"
35
36/*
37 * Runtime implementation of __builtin____vsnprintf_chk.
38 *
39 * See
40 *   http://gcc.gnu.org/onlinedocs/gcc/Object-Size-Checking.html
41 *   http://gcc.gnu.org/ml/gcc-patches/2004-09/msg02055.html
42 * for details.
43 *
44 * This vsnprintf check is called if _FORTIFY_SOURCE is defined and
45 * greater than 0.
46 */
47extern "C" int __vsnprintf_chk(char* dest, size_t supplied_size, int /*flags*/,
48                               size_t dest_len_from_compiler, const char* format, va_list va) {
49  if (__predict_false(supplied_size > dest_len_from_compiler)) {
50    __fortify_chk_fail("vsnprintf: prevented write past end of buffer", 0);
51  }
52
53  return vsnprintf(dest, supplied_size, format, va);
54}
55
56/*
57 * Runtime implementation of __builtin____snprintf_chk.
58 *
59 * See
60 *   http://gcc.gnu.org/onlinedocs/gcc/Object-Size-Checking.html
61 *   http://gcc.gnu.org/ml/gcc-patches/2004-09/msg02055.html
62 * for details.
63 *
64 * This snprintf check is called if _FORTIFY_SOURCE is defined and
65 * greater than 0.
66 */
67extern "C" int __snprintf_chk(char* dest, size_t supplied_size, int flags,
68                              size_t dest_len_from_compiler, const char* format, ...) {
69  va_list va;
70  va_start(va, format);
71  int result = __vsnprintf_chk(dest, supplied_size, flags, dest_len_from_compiler, format, va);
72  va_end(va);
73  return result;
74}
75