Added init_ueventHandler_fuzzer (803b5f42) · Commits · e / os / android_system_core

init/fuzzer/Android.bp

+10 −0

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		@@ -60,3 +60,13 @@ cc_fuzz {
		],
		defaults: ["libinit_defaults"],
		}

		cc_fuzz {
		name: "init_ueventHandler_fuzzer",
		srcs: [
		"init_ueventHandler_fuzzer.cpp",
		],
		defaults: [
		"libinit_defaults",
		],
		}

init/fuzzer/README.md

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		@@ -3,6 +3,7 @@
		## Table of contents
		+ [init_parser_fuzzer](#InitParser)
		+ [init_property_fuzzer](#InitProperty)
		+ [init_ueventHandler_fuzzer](#InitUeventHandler)

		# <a name="InitParser"></a> Fuzzer for InitParser

		@@ -45,3 +46,53 @@ InitProperty supports the following parameters:
		$ adb sync data
		$ adb shell /data/fuzz/arm64/init_property_fuzzer/init_property_fuzzer
		```

		# <a name="InitUeventHandler"></a> Fuzzer for InitUeventHandler

		##### 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.

		InitUeventHandler supports the following parameters:
		1. Major (parameter name: `major`)
		2. Minor (parameter name: `minor`)
		3. PartitionNum (parameter name: `partition_num`)
		4. Uid (parameter name: `uid`)
		5. Gid (parameter name: `gid`)
		6. Action (parameter name: `action`)
		7. Path (parameter name: `path`)
		8. Subsystem (parameter name: `subsystem`)
		9. PartitionName (parameter name: `partition_name`)
		10. DeviceName (parameter name: `device_name`)
		11. Modalias (parameter name: `modalias`)
		12. DevPath (parameter name: `devPath`)
		13. HandlerPath (parameter name: `handlerPath`)

		\| Parameter\| Valid Values\| Configured Value\|
		\|------------- \|-------------\| ----- \|
		\| `major` \| `UINT32_MIN` to `UINT32_MAX` \| Value obtained from FuzzedDataProvider\|
		\| `minor` \| `UINT32_MIN` to `UINT32_MAX` \| Value obtained from FuzzedDataProvider\|
		\| `partition_num ` \| `UINT32_MIN` to `UINT32_MAX` \| Value obtained from FuzzedDataProvider\|
		\| `uid` \| `UINT32_MIN` to `UINT32_MAX` \| Value obtained from FuzzedDataProvider\|
		\| `gid` \| `UINT32_MIN` to `UINT32_MAX` \| Value obtained from FuzzedDataProvider\|
		\| `action` \| `String` \| Value obtained from FuzzedDataProvider\|
		\| `path` \| `String` \| Value obtained from FuzzedDataProvider\|
		\| `subsystem` \| `String` \| Value obtained from FuzzedDataProvider\|
		\| `partition_name` \| `String` \| Value obtained from FuzzedDataProvider\|
		\| `device_name` \| `String` \| Value obtained from FuzzedDataProvider\|
		\| `modalias` \| `String` \| Value obtained from FuzzedDataProvider\|
		\| `devPath` \| `String` \| Value obtained from FuzzedDataProvider\|
		\| `handlerPath` \| `String` \| Value obtained from FuzzedDataProvider\|

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

		#### Steps to run
		1. Build the fuzzer
		```
		$ mm -j$(nproc) init_ueventHandler_fuzzer
		```
		2. Run on device
		```
		$ adb sync data
		$ adb shell /data/fuzz/arm64/init_ueventHandler_fuzzer/init_ueventHandler_fuzzer
		```

init/fuzzer/init_ueventHandler_fuzzer.cpp

0 → 100644

+123 −0

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		/*
		* Copyright (C) 2022 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.
		*/

		#include <devices.h>
		#include <firmware_handler.h>
		#include <fuzzer/FuzzedDataProvider.h>
		#include <modalias_handler.h>
		#include <sys/stat.h>
		#include <util.h>
		#include <fstream>

		using namespace android;
		using namespace android::init;
		constexpr int32_t kMaxBytes = 100;
		constexpr int32_t kMaxSize = 1000;
		constexpr int32_t kMinSize = 1;

		/*'HandleUevent' prefixes the path with '/sys' and hence this is required to point
		* to'/data/local/tmp' dir.*/
		const std::string kPath = "/../data/local/tmp/";
		const std::string kPathPrefix = "/..";

		void MakeFile(FuzzedDataProvider* fdp, std::string s) {
		std::ofstream out;
		out.open(s, std::ios::binary \| std::ofstream::trunc);
		for (int32_t idx = 0; idx < fdp->ConsumeIntegralInRange(kMinSize, kMaxSize); ++idx) {
		out << fdp->ConsumeRandomLengthString(kMaxBytes) << "\n";
		}
		out.close();
		}

		void CreateDir(std::string Directory, FuzzedDataProvider* fdp) {
		std::string tmp = Directory.substr(kPathPrefix.length());
		mkdir_recursive(android::base::Dirname(tmp.c_str()),
		S_IRWXU \| S_IRGRP \| S_IXGRP \| S_IROTH \| S_IXOTH);
		MakeFile(fdp, tmp + "/data");
		MakeFile(fdp, tmp + "/loading");
		}

		std::string SelectRandomString(FuzzedDataProvider* fdp, std::string s) {
		if (fdp->ConsumeBool()) {
		if (fdp->ConsumeBool()) {
		return fdp->ConsumeRandomLengthString(kMaxBytes);
		} else {
		return s;
		}
		}
		return "";
		}

		Uevent CreateUevent(FuzzedDataProvider* fdp) {
		Uevent uevent;
		uevent.action = SelectRandomString(fdp, "add");
		uevent.subsystem = SelectRandomString(fdp, "firmware");
		uevent.path = SelectRandomString(fdp, kPath + fdp->ConsumeRandomLengthString(kMaxBytes));
		uevent.firmware = fdp->ConsumeBool() ? fdp->ConsumeRandomLengthString(kMaxBytes) : "";
		uevent.partition_name = fdp->ConsumeBool() ? fdp->ConsumeRandomLengthString(kMaxBytes) : "";
		uevent.device_name = fdp->ConsumeBool() ? fdp->ConsumeRandomLengthString(kMaxBytes) : "";
		uevent.modalias = fdp->ConsumeBool() ? fdp->ConsumeRandomLengthString(kMaxBytes) : "";
		uevent.partition_num = fdp->ConsumeIntegral<int32_t>();
		uevent.major = fdp->ConsumeIntegral<int32_t>();
		uevent.minor = fdp->ConsumeIntegral<int32_t>();
		return uevent;
		}

		extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
		FuzzedDataProvider fdp(data, size);
		while (fdp.remaining_bytes()) {
		auto invoke_uevent_handler_fuzzer = fdp.PickValueInArray<const std::function<void()>>({
		[&]() {
		std::vector<std::string> modalias_vector;
		for (size_t idx = 0;
		idx < fdp.ConsumeIntegralInRange<size_t>(kMinSize, kMaxSize); ++idx) {
		modalias_vector.push_back(fdp.ConsumeRandomLengthString(kMaxBytes));
		}
		ModaliasHandler modalias_handler = ModaliasHandler(modalias_vector);
		modalias_handler.HandleUevent(CreateUevent(&fdp));
		},
		[&]() {
		std::vector<ExternalFirmwareHandler> external_handlers;
		std::vector<std::string> firmware_directories;
		for (size_t idx = 0;
		idx < fdp.ConsumeIntegralInRange<size_t>(kMinSize, kMaxSize); ++idx) {
		std::string devPath = fdp.ConsumeRandomLengthString(kMaxBytes);
		uid_t uid = fdp.ConsumeIntegral<uid_t>();
		gid_t gid = fdp.ConsumeIntegral<gid_t>();
		std::string handlerPath = fdp.ConsumeRandomLengthString(kMaxBytes);
		ExternalFirmwareHandler externalFirmwareHandler =
		ExternalFirmwareHandler(devPath, uid, gid, handlerPath);
		external_handlers.push_back(externalFirmwareHandler);
		firmware_directories.push_back(fdp.ConsumeRandomLengthString(kMaxBytes));
		}
		FirmwareHandler firmware_handler =
		FirmwareHandler(firmware_directories, external_handlers);
		Uevent uevent = CreateUevent(&fdp);
		if (fdp.ConsumeBool() && uevent.path.size() != 0 &&
		uevent.path.find(kPath) == 0) {
		CreateDir(uevent.path, &fdp);
		firmware_handler.HandleUevent(uevent);
		std::string s = uevent.path.substr(kPathPrefix.length());
		remove(s.c_str());
		} else {
		firmware_handler.HandleUevent(uevent);
		}
		},
		});
		invoke_uevent_handler_fuzzer();
		}
		return 0;
		}