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
|
# qbdi-based binary-only instrumentation for afl-fuzz
## 1) Introduction
The code in ./qbdi_mode allows you to build a standalone feature that
using the QBDI framework to fuzz android native library.
## 2) Build
First download the Android NDK
```
https://developer.android.com/ndk/downloads
https://dl.google.com/android/repository/android-ndk-r20-linux-x86_64.zip
```
Then unzip it and build the standalone-toolchain
For x86_64 standalone-toolchain
```
unzip android-ndk-r20-linux-x86_64.zip
cd android-ndk-r20/
./build/tools/make_standalone_toolchain.py --arch x86_64 --api 21 --install-dir ../android-standalone-toolchain-x86_64
```
For x86 standalone-toolchain
```
./build/tools/make_standalone_toolchain.py --arch x86 --api 21 --install-dir ../android-standalone-toolchain-x86
```
In alternative you can also use the prebuilt toolchain, in that case make sure to set the proper CC and CXX env variables because there are many different compilers for each API version in the prebuilt toolchain.
For example:
```
export STANDALONE_TOOLCHAIN_PATH=~/Android/Sdk/ndk/20.1.5948944/toolchains/llvm/prebuilt/linux-x86_64/
export CC=x86_64-linux-android21-clang
export CXX=x86_64-linux-android21-clang++
```
Then download the QBDI SDK from website
```
https://qbdi.quarkslab.com/
```
For Android x86_64
```
https://github.com/QBDI/QBDI/releases/download/v0.7.0/QBDI-0.7.0-android-X86_64.tar.gz
```
Then decompress the sdk
```
mkdir android-qbdi-sdk-x86_64
cp QBDI-0.7.0-android-X86_64.tar.gz android-qbdi-sdk-x86_64/
cd android-qbdi-sdk-x86_64/
tar xvf QBDI-0.7.0-android-X86_64.tar.gz
```
Now set the `STANDALONE_TOOLCHAIN_PATH` to the path of standalone-toolchain
```
export STANDALONE_TOOLCHAIN_PATH=/home/hac425/workspace/android-standalone-toolchain-x86_64
```
set the `QBDI_SDK_PATH` to the path of QBDI SDK
```
export QBDI_SDK_PATH=/home/hac425/workspace/AFLplusplus/qbdi_mode/android-qbdi-sdk-x86_64/
```
Then run the build.sh
```
./build.sh x86_64
```
this could build the afl-fuzz and also the qbdi template for android x86_64
### Example
The demo-so.c is an vulnerable library, it has a function for test
```c
int target_func(char *buf, int size) {
printf("buffer:%p, size:%p\n", buf, size);
switch (buf[0]) {
case 1:
puts("222");
if (buf[1] == '\x44') {
puts("null ptr deference");
*(char *)(0) = 1;
}
break;
case 0xff:
if (buf[2] == '\xff') {
if (buf[1] == '\x44') {
puts("crash....");
*(char *)(0xdeadbeef) = 1;
}
}
break;
default: puts("default action"); break;
}
return 1;
}
```
This could be build to `libdemo.so`.
Then we should load the library in template.cpp and find the `target` function address.
```c
void *handle = dlopen(lib_path, RTLD_LAZY);
..........................................
..........................................
..........................................
p_target_func = (target_func)dlsym(handle, "target_func");
```
then we read the data from file and call the function in `fuzz_func`
```c
QBDI_NOINLINE int fuzz_func() {
if (afl_setup()) { afl_forkserver(); }
/* Read the input from file */
unsigned long len = 0;
char * data = read_file(input_pathname, &len);
/* Call the target function with the input data */
p_target_func(data, len);
return 1;
}
```
Just compile it
```
./build.sh x86_64
```
Then push the `afl-fuzz`, `loader`, `libdemo.so`, the `libQBDI.so` from the QBDI SDK and the `libc++_shared.so` from android-standalone-toolchain to android device
```
adb push afl-fuzz /data/local/tmp
adb push libdemo.so /data/local/tmp
adb push loader /data/local/tmp
adb push android-qbdi-sdk-x86_64/usr/local/lib/libQBDI.so /data/local/tmp
adb push ../../android-standalone-toolchain-x86_64/sysroot/usr/lib/x86_64-linux-android/libc++_shared.so
/data/local/tmp
```
In android adb shell, run the loader to test if it runs
```
cd /data/local/tmp
export LD_LIBRARY_PATH=/data/local/tmp
mkdir in
echo 0000 > in/1
./loader libdemo.so in/1
p_target_func:0x716d96a98600
offset:0x600
offset:0x580
buffer:0x716d96609050, size:0x5
offset:0x628
offset:0x646
offset:0x64b
offset:0x65c
offset:0x6df
offset:0x590
default action
offset:0x6eb
```
Now run `afl-fuzz` to fuzz the demo library
```
./afl-fuzz -i in -o out -- ./loader /data/local/tmp/libdemo.so @@
```
|
