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 "private/libc_logging.h"
34
35 /*
36 * __fgets_chk. Called in place of fgets() when we know the
37 * size of the buffer we're writing into.
38 *
39 * See
40 * http://gcc.gnu.org/onlinedocs/gcc/Object-Size-Checking.html
41 * for details.
42 *
43 * This fgets check is called if _FORTIFY_SOURCE is defined and
44 * greater than 0.
45 */
__fgets_chk(char * dest,int supplied_size,FILE * stream,size_t dest_len_from_compiler)46 char* __fgets_chk(char* dest, int supplied_size, FILE* stream,
47 size_t dest_len_from_compiler) {
48 if (supplied_size < 0) {
49 __fortify_chk_fail("fgets: buffer size < 0", 0);
50 }
51
52 if (((size_t) supplied_size) > dest_len_from_compiler) {
53 __fortify_chk_fail("fgets: prevented write past end of buffer", 0);
54 }
55
56 return fgets(dest, supplied_size, stream);
57 }
58