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
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
|
/*
american fuzzy lop++ - shared memory related code
-------------------------------------------------
Originally written by Michal Zalewski
Forkserver design by Jann Horn <jannhorn@googlemail.com>
Now maintained by Marc Heuse <mh@mh-sec.de>,
Heiko Eißfeldt <heiko.eissfeldt@hexco.de> and
Andrea Fioraldi <andreafioraldi@gmail.com>
Copyright 2016, 2017 Google Inc. All rights reserved.
Copyright 2019-2020 AFLplusplus Project. All rights reserved.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at:
http://www.apache.org/licenses/LICENSE-2.0
Shared code to handle the shared memory. This is used by the fuzzer
as well the other components like afl-tmin, afl-showmap, etc...
*/
#define AFL_MAIN
#ifdef __ANDROID__
#include "android-ashmem.h"
#endif
#include "config.h"
#include "types.h"
#include "debug.h"
#include "alloc-inl.h"
#include "hash.h"
#include "sharedmem.h"
#include "cmplog.h"
#include "list.h"
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <errno.h>
#include <signal.h>
#include <dirent.h>
#include <fcntl.h>
#include <sys/wait.h>
#include <sys/time.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/resource.h>
#include <sys/mman.h>
#ifndef USEMMAP
#include <sys/ipc.h>
#include <sys/shm.h>
#endif
static list_t shm_list = {.element_prealloc_count = 0};
/* Get rid of shared memory. */
void afl_shm_deinit(sharedmem_t *shm) {
// TODO: clang reports a potential UAF in this function/makro(?)
list_remove(&shm_list, shm);
#ifdef USEMMAP
if (shm->map != NULL) {
munmap(shm->map, shm->map_size);
shm->map = NULL;
}
if (shm->g_shm_fd != -1) {
close(shm->g_shm_fd);
shm->g_shm_fd = -1;
}
#else
shmctl(shm->shm_id, IPC_RMID, NULL);
if (shm->cmplog_mode) shmctl(shm->cmplog_shm_id, IPC_RMID, NULL);
#endif
shm->map = NULL;
}
/* Configure shared memory.
Returns a pointer to shm->map for ease of use.
*/
u8 *afl_shm_init(sharedmem_t *shm, size_t map_size, unsigned char dumb_mode) {
shm->map_size = map_size;
shm->map = NULL;
#ifdef USEMMAP
shm->g_shm_fd = -1;
/* ======
generate random file name for multi instance
thanks to f*cking glibc we can not use tmpnam securely, it generates a
security warning that cannot be suppressed
so we do this worse workaround */
snprintf(shm->g_shm_file_path, L_tmpnam, "/afl_%d_%ld", getpid(), random());
/* create the shared memory segment as if it was a file */
shm->g_shm_fd =
shm_open(shm->g_shm_file_path, O_CREAT | O_RDWR | O_EXCL, 0600);
if (shm->g_shm_fd == -1) { PFATAL("shm_open() failed"); }
/* configure the size of the shared memory segment */
if (ftruncate(shm->g_shm_fd, map_size)) {
PFATAL("setup_shm(): ftruncate() failed");
}
/* map the shared memory segment to the address space of the process */
shm->map = mmap(0, map_size, PROT_READ | PROT_WRITE, MAP_SHARED,
map_size->g_shm_fd, 0);
if (map_size->map == MAP_FAILED) {
close(map_size->g_shm_fd);
map_size->g_shm_fd = -1;
PFATAL("mmap() failed");
}
/* If somebody is asking us to fuzz instrumented binaries in dumb mode,
we don't want them to detect instrumentation, since we won't be sending
fork server commands. This should be replaced with better auto-detection
later on, perhaps? */
if (!dumb_mode) setenv(SHM_ENV_VAR, shm->g_shm_file_path, 1);
if (shm->map == -1 || !shm->map) PFATAL("mmap() failed");
#else
u8 *shm_str;
shm->shm_id = shmget(IPC_PRIVATE, map_size, IPC_CREAT | IPC_EXCL | 0600);
if (shm->shm_id < 0) PFATAL("shmget() failed");
if (shm->cmplog_mode) {
shm->cmplog_shm_id = shmget(IPC_PRIVATE, sizeof(struct cmp_map),
IPC_CREAT | IPC_EXCL | 0600);
if (shm->cmplog_shm_id < 0) PFATAL("shmget() failed");
}
shm_str = alloc_printf("%d", shm->shm_id);
/* If somebody is asking us to fuzz instrumented binaries in dumb mode,
we don't want them to detect instrumentation, since we won't be sending
fork server commands. This should be replaced with better auto-detection
later on, perhaps? */
if (!dumb_mode) setenv(SHM_ENV_VAR, shm_str, 1);
ck_free(shm_str);
if (shm->cmplog_mode) {
shm_str = alloc_printf("%d", shm->cmplog_shm_id);
if (!dumb_mode) setenv(CMPLOG_SHM_ENV_VAR, shm_str, 1);
ck_free(shm_str);
}
shm->map = shmat(shm->shm_id, NULL, 0);
if (shm->map == (void *)-1 || !shm->map) PFATAL("shmat() failed");
if (shm->cmplog_mode) {
shm->cmp_map = shmat(shm->cmplog_shm_id, NULL, 0);
if (shm->cmp_map == (void *)-1 || !shm->cmp_map) PFATAL("shmat() failed");
}
#endif
list_append(&shm_list, shm);
return shm->map;
}
|
