1 /* Copyright (c) 2014, Google Inc.
2 *
3 * Permission to use, copy, modify, and/or distribute this software for any
4 * purpose with or without fee is hereby granted, provided that the above
5 * copyright notice and this permission notice appear in all copies.
6 *
7 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
8 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
9 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
10 * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
11 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
12 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
13 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
14
15 #include <openssl/base.h>
16
17 #if defined(__has_feature)
18 #if __has_feature(address_sanitizer) || __has_feature(memory_sanitizer)
19 #define OPENSSL_ASAN
20 #endif
21 #endif
22
23 #if defined(__GLIBC__) && !defined(__UCLIBC__)
24 #define OPENSSL_GLIBC
25 #endif
26
27 // This file isn't built on ARM or Aarch64 because we link statically in those
28 // builds and trying to override malloc in a static link doesn't work. It also
29 // requires glibc. It's also disabled on ASan builds as this interferes with
30 // ASan's malloc interceptor.
31 //
32 // TODO(davidben): See if this and ASan's and MSan's interceptors can be made to
33 // coexist.
34 #if defined(__linux__) && defined(OPENSSL_GLIBC) && !defined(OPENSSL_ARM) && \
35 !defined(OPENSSL_AARCH64) && !defined(OPENSSL_ASAN)
36
37 #include <errno.h>
38 #include <signal.h>
39 #include <stdint.h>
40 #include <stdio.h>
41 #include <stdlib.h>
42 #include <unistd.h>
43
44 #include <new>
45
46
47 // This file defines overrides for the standard allocation functions that allow
48 // a given allocation to be made to fail for testing. If the program is run
49 // with MALLOC_NUMBER_TO_FAIL set to a base-10 number then that allocation will
50 // return NULL. If MALLOC_BREAK_ON_FAIL is also defined then the allocation
51 // will signal SIGTRAP rather than return NULL.
52 //
53 // This code is not thread safe.
54
55 static uint64_t current_malloc_count = 0;
56 static uint64_t malloc_number_to_fail = 0;
57 static bool failure_enabled = false, break_on_fail = false, in_call = false;
58
59 extern "C" {
60 // These are other names for the standard allocation functions.
61 extern void *__libc_malloc(size_t size);
62 extern void *__libc_calloc(size_t num_elems, size_t size);
63 extern void *__libc_realloc(void *ptr, size_t size);
64 }
65
exit_handler(void)66 static void exit_handler(void) {
67 if (failure_enabled && current_malloc_count > malloc_number_to_fail) {
68 _exit(88);
69 }
70 }
71
cpp_new_handler()72 static void cpp_new_handler() {
73 // Return to try again. It won't fail a second time.
74 return;
75 }
76
77 // should_fail_allocation returns true if the current allocation should fail.
should_fail_allocation()78 static bool should_fail_allocation() {
79 static bool init = false;
80
81 if (in_call) {
82 return false;
83 }
84
85 in_call = true;
86
87 if (!init) {
88 const char *env = getenv("MALLOC_NUMBER_TO_FAIL");
89 if (env != NULL && env[0] != 0) {
90 char *endptr;
91 malloc_number_to_fail = strtoull(env, &endptr, 10);
92 if (*endptr == 0) {
93 failure_enabled = true;
94 atexit(exit_handler);
95 std::set_new_handler(cpp_new_handler);
96 }
97 }
98 break_on_fail = (NULL != getenv("MALLOC_BREAK_ON_FAIL"));
99 init = true;
100 }
101
102 in_call = false;
103
104 if (!failure_enabled) {
105 return false;
106 }
107
108 bool should_fail = (current_malloc_count == malloc_number_to_fail);
109 current_malloc_count++;
110
111 if (should_fail && break_on_fail) {
112 raise(SIGTRAP);
113 }
114 return should_fail;
115 }
116
117 extern "C" {
118
malloc(size_t size)119 void *malloc(size_t size) {
120 if (should_fail_allocation()) {
121 errno = ENOMEM;
122 return NULL;
123 }
124
125 return __libc_malloc(size);
126 }
127
calloc(size_t num_elems,size_t size)128 void *calloc(size_t num_elems, size_t size) {
129 if (should_fail_allocation()) {
130 errno = ENOMEM;
131 return NULL;
132 }
133
134 return __libc_calloc(num_elems, size);
135 }
136
realloc(void * ptr,size_t size)137 void *realloc(void *ptr, size_t size) {
138 if (should_fail_allocation()) {
139 errno = ENOMEM;
140 return NULL;
141 }
142
143 return __libc_realloc(ptr, size);
144 }
145
146 } // extern "C"
147
148 #endif /* defined(linux) && GLIBC && !ARM && !AARCH64 && !ASAN */
149