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README.md

1# Fuzzer for libavc decoder and encoder
2
3This describes steps to build avc_dec_fuzzer and avc_enc_fuzzer.
4
5## Linux x86/x64
6
7###  Requirements
8- cmake (3.9.1 or above)
9- make
10- clang (6.0 or above)
11  needs to support -fsanitize=fuzzer, -fsanitize=fuzzer-no-link
12
13### Steps to build
14Clone libavc repository
15```
16$ git clone https://android.googlesource.com/platform/external/libavc
17```
18Create a directory inside libavc and change directory
19```
20 $ cd libavc
21 $ mkdir build
22 $ cd build
23```
24Build fuzzer with required sanitizers (-DSANITIZE=fuzzer-no-link is mandatory
25  to enable fuzzers)
26```
27 $ cmake .. -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ \
28   -DCMAKE_BUILD_TYPE=Debug -DSANITIZE=fuzzer-no-link,address
29 $ make
30 ```
31
32### Steps to run
33Create a directory CORPUS_DIR and copy some elementary h264 files
34(for avc_dec_fuzzer) or yuv files (for avc_enc_fuzzer) to that directory
35
36To run the fuzzers
37```
38$ ./avc_dec_fuzzer CORPUS_DIR
39$ ./avc_enc_fuzzer CORPUS_DIR
40```
41
42## Android
43
44### Steps to build
45Build the fuzzers
46```
47  $ mm -j$(nproc) avc_dec_fuzzer
48  $ mm -j$(nproc) avc_enc_fuzzer
49```
50
51### Steps to run
52Create a directory CORPUS_DIR and copy some elementary h264 files
53(for avc_dec_fuzzer) or yuv files (for avc_enc_fuzzer) to that folder
54Push this directory to device
55
56To run avc_dec_fuzzer on device
57```
58  $ adb sync data
59  $ adb shell /data/fuzz/arm64/avc_dec_fuzzer/avc_dec_fuzzer CORPUS_DIR
60```
61To run avc_enc_fuzzer on device
62```
63  $ adb sync data
64  $ adb shell /data/fuzz/arm64/avc_enc_fuzzer/avc_enc_fuzzer CORPUS_DIR
65```
66
67To run avc_dec_fuzzer on host
68```
69  $ $ANDROID_HOST_OUT/fuzz/x86_64/avc_dec_fuzzer/avc_dec_fuzzer CORPUS_DIR
70```
71
72To run avc_enc_fuzzer on host
73```
74  $ $ANDROID_HOST_OUT/fuzz/x86_64/avc_enc_fuzzer/avc_enc_fuzzer CORPUS_DIR
75```
76
77
78# Appendix
79## libavc encoder fuzzer
80
81## Plugin Design Considerations
82The fuzzer plugin for AVC is designed based on the understanding of the
83codec and tries to achieve the following:
84
85##### Maximize code coverage
86The configuration parameters are not hardcoded, but instead selected based on
87incoming data. This ensures more code paths are reached by the fuzzer.
88
89AVC supports the following parameters:
901. Frame Width (parameter name: `u4_wd`)
912. Frame Height (parameter name: `u4_ht`)
923. Input color format  (parameter name: `e_inp_color_fmt`)
934. Architecture type (parameter name: `e_arch`)
945. Rate control mode (parameter name: `e_rc_mode`)
956. Number of cores (parameter name: `u4_num_cores`)
967. Maximum B frames (parameter name: `u4_num_bframes`)
978. Encoder speed preset (parameter name: `u4_enc_speed_preset`)
989. enable constrained intra prediction (parameter name: `u4_constrained_intra_pred`)
9910. enable intra 4x4 (parameter name: `u4_enable_intra_4x4`)
10011. Qp for I frames (parameter name: `u4_i_qp`)
10112. Qp for P frames (parameter name: `u4_p_qp`)
10213. Qp for B frames (parameter name: `u4_b_qp`)
10314. Target Bitrate (parameter name: `u4_target_bitrate`)
10415. Intra refresh period in frames (parameter name: `u4_air_refresh_period`)
10516. Enable half pel ME (parameter name: `u4_enable_hpel`)
10617. Enable quarter pel ME (parameter name: `u4_enable_qpel`)
10718. ME speed preset (parameter name: `u4_me_speed_preset`)
10819. Adaptive intra refresh mode (parameter name: `e_air_mode`)
10920. Disable deblock level (parameter name: `u4_disable_deblock_level`)
11021. Max search range in X direction (parameter name: `u4_srch_rng_x`)
11122. Max search range in Y direction (parameter name: `u4_srch_rng_y`)
11223. I frame interval (parameter name: `u4_i_frm_interval`)
11324. IDR frame interval (parameter name: `u4_idr_frm_interval`)
11425. Enable mastering display color volume info (parameter name: `u1_sei_mdcv_params_present_flag`)
11526. Enable content light level info (parameter name: `u1_sei_cll_params_present_flag`)
11627. Enable ambient viewing environment info (parameter name: `u1_sei_ave_params_present_flag`)
11728. Enable content color volume info (parameter name: `u1_sei_ccv_params_present_flag`)
11829. Profile (parameter name: `e_profile`)
11930. Enable aspect_ratio info (parameter name: `u1_aspect_ratio_info_present_flag`)
12031. Enable NAL HRD parameters presence (parameter name: `u1_nal_hrd_parameters_present_flag`)
12132. Enable VCL HRD parameters presence (parameter name: `u1_vcl_hrd_parameters_present_flag`)
12233. Enable force IDR frame (parameter name: `mIsForceIdrEnabled`)
12334. Enable dynamic bitrate change (parameter name: `mIsDynamicBitRateChangeEnabled`)
12435. Enable dynamic framerate change (parameter name: `mIsDynamicFrameRateChangeEnabled`)
12536. Force IDR frame number (parameter name: `mForceIdrInterval`)
12637. Frame number for dynamic bitrate (parameter name: `mDynamicBitRateInterval`)
12738. Frame number for dynamic framerate (parameter name: `mDynamicFrameRateInterval`)
128
129| Parameter| Valid Values| Configured Value|
130|------------- |-------------| ----- |
131| `u4_wd` | In the range `0 to 10239` | All the bits of 1st and 2nd byte of data |
132| `u4_ht` | In the range `0 to 10239` | All the bits of 3rd and 4th byte of data |
133| `e_inp_color_fmt` | 0. `IV_YUV_420P` 1. `IV_YUV_420SP_UV` 2. `IV_YUV_422ILE` 3. `IV_YUV_420SP_VU` | All the bits of 5th byte of data |
134| `e_arch` | 0. `ARCH_ARM_NONEON` 1. `ARCH_NA` | bit 0 and 1 of 6th byte of data |
135| `e_rc_mode` | 0. `IVE_RC_NONE` 1. `IVE_RC_STORAGE` 2. `IVE_RC_CBR_NON_LOW_DELAY` 3. `IVE_RC_CBR_LOW_DELAY` | All the bits of 7th byte of data modulus 4 |
136| `u4_num_cores` | 0. `0` 1. `1` 2. `2` 3. `3`| bit 0 and 1 of 8th byte of data |
137| `u4_num_bframes` | In the range `0 to 7` | bit 0, 1 and 2 of 9th byte of data |
138| `u4_enc_speed_preset` | 0. `IVE_CONFIG` 1. `IVE_SLOWEST` 2. `IVE_NORMAL` 3. `IVE_FAST` 4. `IVE_HIGH_SPEED` 5. `IVE_FASTEST` | All the bits of 10th byte of data modulus 6 |
139| `u4_constrained_intra_pred` | 0. `0` 1. `1` | bit 0 of 11th byte of data |
140| `u4_enable_intra_4x4` | 0. `0` 1. `1` | bit 0 of 12th byte of data |
141| `u4_i_qp` | In the range `4 to 51` | All the bits of 13th byte of data |
142| `u4_p_qp` | In the range `4 to 51` | All the bits of 14th byte of data |
143| `u4_b_qp` | In the range `4 to 51` | All the bits of 15th byte of data |
144| `u4_target_bitrate` | In the range `0 to 500000000` | All the bits of 16th and 17th byte of data |
145| `u4_target_bitrate` | In the range `0 to 255` | All the bits of 18th byte of data |
146| `u4_air_refresh_period` | In the range `1 to 256` | All the bits of 19th byte of data |
147| `u4_air_refresh_period` | In the range `1 to 256` | All the bits of 19th byte of data |
148| `u4_enable_hpel` | 0. `0` 1. `1` | bit 0 of 20th byte of data |
149| `u4_enable_qpel` | 0. `0` 1. `1` | bit 0 of 21st byte of data |
150| `u4_me_speed_preset` | 0. `0` 1. `50` 2. `75` 3. `100` | All the bits of 22nd byte of data modulus 4 |
151| `e_air_mode` | 0. `IVE_AIR_MODE_NONE` 1. `IVE_AIR_MODE_CYCLIC` 2. `IVE_AIR_MODE_RANDOM` | All the bits of 23rd byte of data modulus 3 |
152| `u4_disable_deblock_level` | 0. `0` 1. `1` 2. `2` 3. `3` | bit 0 and 1 of 24th byte of data |
153| `u4_srch_rng_x` | In the range `0 to 255` | All the bits of 25th byte of data |
154| `u4_srch_rng_y` | In the range `0 to 255`| All the bits of 26th byte of data |
155| `u4_i_frm_interval` | In the range `1 to 256` | All the bits of 27th byte of data |
156| `u4_idr_frm_interval` | In the range `1 to 256` | All the bits of 28th byte of data |
157| `u1_sei_mdcv_params_present_flag` | 0. `0` 1. `1` | bit 0 of 29th byte of data |
158| `u1_sei_cll_params_present_flag` | 0. `0` 1. `1` | bit 0 of 30th byte of data |
159| `u1_sei_ave_params_present_flag` | 0. `0` 1. `1` | bit 0 of 31st byte of data |
160| `u1_sei_ccv_params_present_flag` | 0. `0` 1. `1` | bit 0 of 32nd byte of data |
161| `e_profile` | 0. `IV_PROFILE_BASE` 1. `IV_PROFILE_MAIN` | bit 0 and 1 of 33th byte of data modulus 2 |
162| `u1_aspect_ratio_info_present_flag` | 0. `0` 1. `1` | bit 0 of 34th byte of data |
163| `u1_nal_hrd_parameters_present_flag` | 0. `0` 1. `1` | bit 0 of 35th byte of data |
164| `u1_vcl_hrd_parameters_present_flag` | 0. `0` 1. `1` | bit 0 of 36th byte of data |
165| `mIsForceIdrEnabled` | 0. `0` 1. `1` | bit 0 of 37th byte of data |
166| `mIsDynamicBitRateChangeEnabled` | 0. `0` 1. `1` | bit 0 of 38th byte of data |
167| `mIsDynamicFrameRateChangeEnabled` | 0. `0` 1. `1` | bit 0 of 39th byte of data |
168| `mForceIdrInterval` | In the range `0 to 7` | bit 0, 1 and 2 of 40th byte of data |
169| `mDynamicBitRateInterval` | In the range `0 to 7` | bit 0, 1 and 2 of 41st byte of data |
170| `mDynamicFrameRateInterval` | In the range `0 to 7` | bit 0, 1 and 2 of 42nd byte of data |
171
172This also ensures that the plugin is always deterministic for any given input.
173
174##### Maximize utilization of input data
175The plugin feeds the entire input data to the codec using a loop.
176If the encode operation was successful, the input is advanced by the frame size.
177If the encode operation was un-successful, the input is still advanced by frame size so
178that the fuzzer can proceed to feed the next frame.
179
180This ensures that the plugin tolerates any kind of input (empty, huge,
181malformed, etc) and doesnt `exit()` on any input and thereby increasing the
182chance of identifying vulnerabilities.
183
184
185## References:
186 * http://llvm.org/docs/LibFuzzer.html
187 * https://github.com/google/oss-fuzz
188