1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
|
/*
* Copyright (C) 2012 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <string.h>
#include <stdlib.h>
#include "libc_logging.h"
#include <safe_iop.h>
/*
* Runtime implementation of __builtin____strncat_chk.
*
* See
* http://gcc.gnu.org/onlinedocs/gcc/Object-Size-Checking.html
* http://gcc.gnu.org/ml/gcc-patches/2004-09/msg02055.html
* for details.
*
* This strncat check is called if _FORTIFY_SOURCE is defined and
* greater than 0.
*/
extern "C" char *__strncat_chk (char *dest, const char *src,
size_t len, size_t dest_buf_size)
{
// TODO: optimize so we don't scan src/dest twice.
size_t dest_len = strlen(dest);
size_t src_len = strlen(src);
if (src_len > len) {
src_len = len;
}
size_t sum;
// sum = src_len + dest_len + 1 (with overflow protection)
if (!safe_add3(&sum, src_len, dest_len, 1U)) {
__fortify_chk_fail("strncat integer overflow",
BIONIC_EVENT_STRNCAT_INTEGER_OVERFLOW);
}
if (sum > dest_buf_size) {
__fortify_chk_fail("strncat buffer overflow",
BIONIC_EVENT_STRNCAT_BUFFER_OVERFLOW);
}
return strncat(dest, src, len);
}
|
