Added audioflinger_fuzzer

/*

 * Copyright (C) 2021 The Android Open Source Project

 *

 * 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

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

cc_fuzz {

    name: "audioflinger_fuzzer",

    srcs: [

        "audioflinger_fuzzer.cpp",

    ],

    static_libs: [

        "android.hardware.audio.common@7.0-enums",

        "effect-aidl-unstable-cpp",

        "libaudioclient",

        "libbase",

        "libcgrouprc",

        "libcgrouprc_format",

        "libcutils",

        "libjsoncpp",

        "liblog",

        "libmediametrics",

        "libmediametricsservice",

        "libmedia_helper",

        "libprocessgroup",

        "shared-file-region-aidl-unstable-cpp",

    ],

    shared_libs: [

        "android.hardware.audio.common-util",

        "audioclient-types-aidl-unstable-cpp",

        "audioflinger-aidl-unstable-cpp",

        "audiopolicy-aidl-unstable-cpp",

        "audiopolicy-types-aidl-unstable-cpp",

        "av-types-aidl-unstable-cpp",

        "capture_state_listener-aidl-unstable-cpp",

        "libaudioclient_aidl_conversion",

        "libaudioflinger",

        "libaudiofoundation",

        "libaudiomanager",

        "libaudiopolicy",

        "libaudioutils",

        "libbinder",

        "libdl",

        "libmediautils",

        "libnblog",

        "libutils",

        "libxml2",

        "mediametricsservice-aidl-unstable-cpp",

    ],

    header_libs: [

        "libaudiofoundation_headers",

        "libmedia_headers",

    ],

    fuzz_config: {

        cc: [

            "android-media-fuzzing-reports@google.com",

        ],

        componentid: 155276,

    },

}

# Fuzzer for libaudioflinger

## Plugin Design Considerations

The fuzzer plugin for libaudioflinger is designed based on the understanding of the

library and tries to achieve the following:

##### Maximize code coverage

The configuration parameters are not hardcoded, but instead selected based on

incoming data. This ensures more code paths are reached by the fuzzer. The fuzzer

covers libaudioflinger APIs as called from libaudioclient through IPC.

libaudioflinger supports the following parameters:

1. Unique IDs (parameter name: `uniqueId`)

2. Audio Mode (parameter name: `mode`)

3. Session ID (parameter name: `sessionId`)

4. Encapsulation Mode (parameter name: `encapsulationMode`)

5. Audio Port Role (parameter name: `portRole`)

6. Audio Port Type (parameter name: `portType`)

7. Audio Stream Type (parameter name: `streamType`)

8. Audio Format (parameter name: `format`)

9. Audio Channel Mask (parameter name: `channelMask`)

10. Usage (parameter name: `usage`)

11. Audio Content Type (parameter name: `contentType`)

12. Input Source (parameter name: `inputSource`)

13. Input Flags (parameter name: `inputFlags`)

14. Output Flags (parameter name: `outputFlags`)

15. Audio Gain Mode (parameter name: `gainMode`)

16. Audio Device (parameter name: `device`)

| Parameter| Valid Values| Configured Value|

|------------- |-------------| ----- |

| `uniqueId`   | 0. `AUDIO_UNIQUE_ID_USE_UNSPECIFIED` 1. `AUDIO_UNIQUE_ID_USE_SESSION` 2. `AUDIO_UNIQUE_ID_USE_MODULE` 3. `AUDIO_UNIQUE_ID_USE_EFFECT` 4. `AUDIO_UNIQUE_ID_USE_PATCH` 5. `AUDIO_UNIQUE_ID_USE_OUTPUT` 6. `AUDIO_UNIQUE_ID_USE_INPUT` 7. `AUDIO_UNIQUE_ID_USE_CLIENT` 8. `AUDIO_UNIQUE_ID_USE_MAX` | Value obtained from FuzzedDataProvider

| `mode`   | 0.`AUDIO_MODE_INVALID` 1. `AUDIO_MODE_CURRENT` 2. ` AUDIO_MODE_NORMAL` 3. `AUDIO_MODE_RINGTONE` 4. `AUDIO_MODE_IN_CALL` 5. `AUDIO_MODE_IN_COMMUNICATION` 6. `AUDIO_MODE_CALL_SCREEN` | Value obtained from FuzzedDataProvider|

| `sessionId`   | 0. `AUDIO_SESSION_NONE` 1. `AUDIO_SESSION_OUTPUT_STAGE` 2. `AUDIO_SESSION_DEVICE` | Value obtained from FuzzedDataProvider|

| `encapsulationMode`   | 0. `AUDIO_ENCAPSULATION_MODE_NONE` 1. `AUDIO_ENCAPSULATION_MODE_ELEMENTARY_STREAM` 2. `AUDIO_ENCAPSULATION_MODE_HANDLE` | Value obtained from FuzzedDataProvider|

| `portRole`   | 0. `AUDIO_PORT_ROLE_NONE` 1. `AUDIO_PORT_ROLE_SOURCE` 2. `AUDIO_PORT_ROLE_SINK` | Value obtained from FuzzedDataProvider|

| `portType`   | 0. `AUDIO_PORT_TYPE_NONE` 1. `AUDIO_PORT_TYPE_DEVICE` 2. `AUDIO_PORT_TYPE_MIX` 3. `AUDIO_PORT_TYPE_SESSION`| Value obtained from FuzzedDataProvider|

| `streamType` | 15 values of type `audio_stream_type_t` | Value chosen from valid values by obtaining index from FuzzedDataProvider |

| `format` | 77 values of type `audio_format_t` | Value chosen from valid values by obtaining index from FuzzedDataProvider |

| `channelMask` | 83 values of type `audio_channel_mask_t` | Value chosen from valid values by obtaining index from FuzzedDataProvider |

| `usage` | 22 values of type `audio_usage_t` | Value chosen from valid values by obtaining index from FuzzedDataProvider |

| `contentType` | 5 values of type `audio_content_type_t` | Value chosen from valid values by obtaining index from FuzzedDataProvider |

| `inputSource` | 14 values of type `audio_source_t` | Value chosen from valid values by obtaining index from FuzzedDataProvider |

| `inputFlags` | 9 values of type `audio_input_flags_t` | Value chosen from valid values by obtaining index from FuzzedDataProvider |

| `outputFlags` | 16 values of type `audio_output_flags_t` | Value chosen from valid values by obtaining index from FuzzedDataProvider |

| `gainMode` | 3 values of type `audio_gain_mode_t` | Value chosen from valid values by obtaining index from FuzzedDataProvider |

| `device` | 66 values of type `audio_devices_t` | Value chosen from valid values by obtaining index from FuzzedDataProvider |

This also ensures that the plugin is always deterministic for any given input.

##### Maximize utilization of input data

The plugin tolerates any kind of input (empty, huge,

malformed, etc) and doesn't `exit()` on any input and thereby increasing the

chance of identifying vulnerabilities.

## Build

This describes steps to build audioflinger_fuzzer binary.

### Android

#### Steps to build

Build the fuzzer

```

  $ mm -j$(nproc) audioflinger_fuzzer

```

#### Steps to run

Create a directory CORPUS_DIR and copy some files to that folder

Push this directory to device.

To run on device

```

  $ adb sync data

  $ adb shell /data/fuzz/arm64/audioflinger_fuzzer/audioflinger_fuzzer CORPUS_DIR

```

## References:

 * http://llvm.org/docs/LibFuzzer.html

 * https://github.co