Added fuzzers for libkeymaster4support (20bf5e70) · Commits · e / os / android_hardware_interfaces

keymaster/4.0/support/fuzzer/Android.bp

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		/*
		* 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_defaults {
		name: "keymaster4_fuzzer_defaults",
		static_libs: [
		"libbase",
		"liblog",
		"libkeymaster4support",
		"libutils",
		],
		shared_libs: [
		"android.hardware.keymaster@4.0",
		"libcrypto",
		"libhidlbase",
		],
		fuzz_config: {
		cc: [
		"android-media-fuzzing-reports@google.com",
		],
		componentid: 533764,
		},
		}

		cc_fuzz {
		name: "keymaster4_attestation_fuzzer",
		defaults: [
		"keymaster4_fuzzer_defaults",
		],
		srcs: [
		"keymaster4_attestation_fuzzer.cpp",
		],
		}

		cc_fuzz {
		name: "keymaster4_authSet_fuzzer",
		defaults: [
		"keymaster4_fuzzer_defaults",
		],
		srcs: [
		"keymaster4_authSet_fuzzer.cpp",
		],
		}

		cc_fuzz {
		name: "keymaster4_utils_fuzzer",
		defaults: [
		"keymaster4_fuzzer_defaults",
		],
		srcs: [
		"keymaster4_utils_fuzzer.cpp",
		],
		}

keymaster/4.0/support/fuzzer/README.md

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		# Fuzzers for libkeymaster4support

		## Plugin Design Considerations
		The fuzzer plugins for libkeymaster4support are designed based on the understanding of the
		source code and try 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 fuzzers.

		libkeymaster4support supports the following parameters:
		1. Security Level (parameter name: `securityLevel`)
		2. Ec Curve (parameter name: `ecCurve`)
		3. Padding Mode (parameter name: `paddingMode`)
		4. Digest (parameter name: `digest`)
		5. Tag (parameter name: `tag`)

		\| Parameter\| Valid Values\| Configured Value\|
		\|------------- \|-------------\| ----- \|
		\| `securityLevel` \| 0.`SecurityLevel::SOFTWARE` 1.`SecurityLevel::TRUSTED_ENVIRONMENT` 2.`SecurityLevel::STRONGBOX`\| Value obtained from FuzzedDataProvider\|
		\| `ecCurve` \| 0.`EcCurve::P_224` 1.`EcCurve::P_256` 2.`EcCurve::P_384` 3. `EcCurve::P_521`\| Value obtained from FuzzedDataProvider\|
		\| `paddingMode` \| 0.`PaddingMode::NONE` 1.`PaddingMode::RSA_OAEP` 2.`PaddingMode::RSA_PSS` 3. `PaddingMode::RSA_PKCS1_1_5_ENCRYPT` 4.`PaddingMode::RSA_PKCS1_1_5_SIGN` 5.`PaddingMode::PKCS7`\| Value obtained from FuzzedDataProvider\|
		\| `digest` \| 1. `Digest::NONE` 2.`Digest::MD5` 3.`Digest::SHA1` 4.`Digest::SHA_2_224` 5.`Digest::SHA_2_256` 6.`Digest::SHA_2_384` 7.`Digest::SHA_2_512`\| Value obtained from FuzzedDataProvider\|
		\| `tag` \| 1. `Tag::INVALID` 2.`Tag::PURPOSE` 3.`Tag::ALGORITHM` 4.`Tag::KEY_SIZE` 5.`Tag::BLOCK_MODE` 6.`Tag::DIGEST` 7.`Tag::PADDING` 8.`Tag::CALLER_NONCE` 9.`Tag::MIN_MAC_LENGTH` 10.`Tag::EC_CURVE` 11.`Tag::RSA_PUBLIC_EXPONENT` 12.`Tag::INCLUDE_UNIQUE_ID` 13. `Tag::BLOB_USAGE_REQUIREMENTS` 14.`Tag::BOOTLOADER_ONLY` 15.`Tag::ROLLBACK_RESISTANCE` 16.`Tag::HARDWARE_TYPE` 17.`Tag::ACTIVE_DATETIME` 18. `Tag::ORIGINATION_EXPIRE_DATETIME` 19.`Tag::USAGE_EXPIRE_DATETIME` 20.`Tag::MIN_SECONDS_BETWEEN_OPS` 21.`Tag::MAX_USES_PER_BOOT` 22.`Tag::USER_ID` 23.` Tag::USER_SECURE_ID` 24.`Tag::NO_AUTH_REQUIRED` 25.`Tag::USER_AUTH_TYPE` 26.`Tag::AUTH_TIMEOUT` 27.`Tag::ALLOW_WHILE_ON_BODY` 28.`Tag::TRUSTED_USER_PRESENCE_REQUIRED` 29.`Tag::TRUSTED_CONFIRMATION_REQUIRED` 30.`Tag::UNLOCKED_DEVICE_REQUIRED` 31.`Tag::APPLICATION_ID` 32.`Tag::APPLICATION_DATA` 33.`Tag::CREATION_DATETIME` 34.`Tag::ORIGIN` 35.`Tag::ROOT_OF_TRUST` 36.`Tag::OS_VERSION` 37.`Tag::OS_PATCHLEVEL` 38.`Tag::UNIQUE_ID` 39.`Tag::ATTESTATION_CHALLENGE` 40.`Tag::ATTESTATION_APPLICATION_ID` 41.`Tag::ATTESTATION_ID_BRAND` 42.`Tag::ATTESTATION_ID_DEVICE` 43.`Tag::ATTESTATION_ID_PRODUCT` 44.`Tag::ATTESTATION_ID_SERIAL` 45.`Tag::ATTESTATION_ID_IMEI` 46.`Tag::ATTESTATION_ID_MEID` 47.`Tag::ATTESTATION_ID_MANUFACTURER` 48.`Tag::ATTESTATION_ID_MODEL` 49.`Tag::VENDOR_PATCHLEVEL` 50.`Tag::BOOT_PATCHLEVEL` 51.`Tag::ASSOCIATED_DATA` 52.`Tag::NONCE` 53.`Tag::MAC_LENGTH` 54.`Tag::RESET_SINCE_ID_ROTATION` 55.`Tag::CONFIRMATION_TOKEN`\| Value obtained from FuzzedDataProvider\|

		This also ensures that the plugins are always deterministic for any given input.

		##### Maximize utilization of input data
		The plugins feed the entire input data to the module.
		This ensures that the plugins tolerate any kind of input (empty, huge,
		malformed, etc) and dont `exit()` on any input and thereby increasing the
		chance of identifying vulnerabilities.

		## Build

		This describes steps to build keymaster4_attestation_fuzzer, keymaster4_authSet_fuzzer and keymaster4_utils_fuzzer binaries

		### Android

		#### Steps to build
		Build the fuzzer
		```
		$ mm -j$(nproc) keymaster4_attestation_fuzzer
		$ mm -j$(nproc) keymaster4_authSet_fuzzer
		$ mm -j$(nproc) keymaster4_utils_fuzzer
		```
		#### Steps to run
		To run on device
		```
		$ adb sync data
		$ adb shell /data/fuzz/${TARGET_ARCH}/keymaster4_attestation_fuzzer/keymaster4_attestation_fuzzer
		$ adb shell /data/fuzz/${TARGET_ARCH}/keymaster4_authSet_fuzzer/keymaster4_authSet_fuzzer
		$ adb shell /data/fuzz/${TARGET_ARCH}/keymaster4_utils_fuzzer/keymaster4_utils_fuzzer
		```

		## References:
		* http://llvm.org/docs/LibFuzzer.html
		* https://github.com/google/oss-fuzz

keymaster/4.0/support/fuzzer/keymaster4_attestation_fuzzer.cpp

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		/*
		* 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.
		*
		*/
		#include <android/hardware/keymaster/4.0/IKeymasterDevice.h>
		#include <keymasterV4_0/attestation_record.h>
		#include <keymasterV4_0/openssl_utils.h>
		#include "keymaster4_common.h"

		namespace android::hardware::keymaster::V4_0::fuzzer {

		constexpr size_t kMinBytes = 1;
		constexpr size_t kMaxBytes = 10;

		class KeyMaster4AttestationFuzzer {
		public:
		void process(const uint8_t* data, size_t size);

		private:
		ErrorCode generateKey(const AuthorizationSet& keyDesc, hidl_vec<uint8_t>* keyBlob,
		KeyCharacteristics* keyCharacteristics);
		ErrorCode attestKey(hidl_vec<uint8_t>& keyBlob, const AuthorizationSet& attestParams,
		hidl_vec<hidl_vec<uint8_t>>* certificateChain);
		X509_Ptr parseCertificateBlob(const hidl_vec<uint8_t>& blob);
		ASN1_OCTET_STRING* getAttestationRecord(const X509* certificate);
		bool verifyAttestationRecord(const hidl_vec<uint8_t>& attestationCert);
		void invokeAttestationRecord();

		sp<IKeymasterDevice> mKeymaster = nullptr;
		std::unique_ptr<FuzzedDataProvider> mFdp = nullptr;
		};

		ErrorCode KeyMaster4AttestationFuzzer::generateKey(const AuthorizationSet& key_desc,
		hidl_vec<uint8_t>* keyBlob,
		KeyCharacteristics* keyCharacteristics) {
		ErrorCode error;
		mKeymaster->generateKey(key_desc.hidl_data(),
		[&](ErrorCode hidlError, const hidl_vec<uint8_t>& hidlKeyBlob,
		const KeyCharacteristics& hidlKeyCharacteristics) {
		error = hidlError;
		*keyBlob = hidlKeyBlob;
		*keyCharacteristics = hidlKeyCharacteristics;
		});
		return error;
		}

		ErrorCode KeyMaster4AttestationFuzzer::attestKey(hidl_vec<uint8_t>& keyBlob,
		const AuthorizationSet& attestParams,
		hidl_vec<hidl_vec<uint8_t>>* certificateChain) {
		ErrorCode error;
		auto rc = mKeymaster->attestKey(
		keyBlob, attestParams.hidl_data(),
		[&](ErrorCode hidlError, const hidl_vec<hidl_vec<uint8_t>>& hidlCertificateChain) {
		error = hidlError;
		*certificateChain = hidlCertificateChain;
		});

		if (!rc.isOk()) {
		return ErrorCode::UNKNOWN_ERROR;
		}
		return error;
		}

		X509_Ptr KeyMaster4AttestationFuzzer::parseCertificateBlob(const hidl_vec<uint8_t>& blob) {
		const uint8_t* p = blob.data();
		return X509_Ptr(d2i_X509(nullptr, &p, blob.size()));
		}

		/**
		* @brief getAttestationRecord() accepts a 'certificate' pointer and the return value points to the
		* data owned by 'certificate'. Hence, 'certificate' should not be freed and the return value cannot
		* outlive 'certificate'
		*/
		ASN1_OCTET_STRING* KeyMaster4AttestationFuzzer::getAttestationRecord(const X509* certificate) {
		ASN1_OBJECT_Ptr oid(OBJ_txt2obj(kAttestionRecordOid, 1 /* dotted string format */));
		if (!oid.get()) {
		return nullptr;
		}

		int location = X509_get_ext_by_OBJ(certificate, oid.get(), -1 /* search from beginning */);
		if (location == -1) {
		return nullptr;
		}

		X509_EXTENSION* attestRecordExt = X509_get_ext(certificate, location);
		if (!attestRecordExt) {
		return nullptr;
		}

		ASN1_OCTET_STRING* attestRecord = X509_EXTENSION_get_data(attestRecordExt);
		return attestRecord;
		}

		bool KeyMaster4AttestationFuzzer::verifyAttestationRecord(
		const hidl_vec<uint8_t>& attestationCert) {
		X509_Ptr cert(parseCertificateBlob(attestationCert));
		if (!cert.get()) {
		return false;
		}

		ASN1_OCTET_STRING* attestRecord = getAttestationRecord(cert.get());
		if (!attestRecord) {
		return false;
		}

		AuthorizationSet attestationSwEnforced;
		AuthorizationSet attestationHwEnforced;
		uint32_t attestationVersion;
		uint32_t keymasterVersion;
		SecurityLevel securityLevel;
		SecurityLevel keymasterSecurityLevel;
		hidl_vec<uint8_t> attestationChallenge;
		hidl_vec<uint8_t> attestationUniqueId;

		auto error = parse_attestation_record(
		attestRecord->data, attestRecord->length, &attestationVersion, &securityLevel,
		&keymasterVersion, &keymasterSecurityLevel, &attestationChallenge,
		&attestationSwEnforced, &attestationHwEnforced, &attestationUniqueId);
		if (error != ErrorCode::OK) {
		return false;
		}

		hidl_vec<uint8_t> verifiedBootKey;
		keymaster_verified_boot_t verifiedBootState;
		bool device_locked;
		hidl_vec<uint8_t> verifiedBootHash;

		parse_root_of_trust(attestRecord->data, attestRecord->length, &verifiedBootKey,
		&verifiedBootState, &device_locked, &verifiedBootHash);
		return true;
		}

		void KeyMaster4AttestationFuzzer::invokeAttestationRecord() {
		mKeymaster = IKeymasterDevice::getService();
		if (!mKeymaster) {
		return;
		}

		hidl_vec<uint8_t> keyBlob;
		KeyCharacteristics keyCharacteristics;
		generateKey(createAuthorizationSet(mFdp), &keyBlob, &keyCharacteristics);

		hidl_vec<hidl_vec<uint8_t>> certificateChain;

		std::vector<uint8_t> challenge, attestationId;
		challenge =
		mFdp->ConsumeBytes<uint8_t>(mFdp->ConsumeIntegralInRange<size_t>(kMinBytes, kMaxBytes));
		attestationId =
		mFdp->ConsumeBytes<uint8_t>(mFdp->ConsumeIntegralInRange<size_t>(kMinBytes, kMaxBytes));
		attestKey(keyBlob,
		AuthorizationSetBuilder()
		.Authorization(TAG_ATTESTATION_CHALLENGE, challenge)
		.Authorization(TAG_ATTESTATION_APPLICATION_ID, attestationId),
		&certificateChain);

		if (certificateChain.size() > 0) {
		verifyAttestationRecord(certificateChain[mFdp->ConsumeIntegralInRange<size_t>(
		0, certificateChain.size() - 1)]);
		}
		}

		void KeyMaster4AttestationFuzzer::process(const uint8_t* data, size_t size) {
		mFdp = std::make_unique<FuzzedDataProvider>(data, size);
		invokeAttestationRecord();
		}

		extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
		KeyMaster4AttestationFuzzer km4AttestationFuzzer;
		km4AttestationFuzzer.process(data, size);
		return 0;
		}

		} // namespace android::hardware::keymaster::V4_0::fuzzer

keymaster/4.0/support/fuzzer/keymaster4_authSet_fuzzer.cpp

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		/*
		* 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.
		*
		*/
		#include <fstream>
		#include "keymaster4_common.h"

		namespace android::hardware::keymaster::V4_0::fuzzer {

		constexpr size_t kMaxVectorSize = 100;
		constexpr size_t kMaxKeyParameter = 10;

		constexpr Tag kTagArray[] = {Tag::INVALID,
		Tag::PURPOSE,
		Tag::ALGORITHM,
		Tag::KEY_SIZE,
		Tag::BLOCK_MODE,
		Tag::DIGEST,
		Tag::PADDING,
		Tag::CALLER_NONCE,
		Tag::MIN_MAC_LENGTH,
		Tag::EC_CURVE,
		Tag::RSA_PUBLIC_EXPONENT,
		Tag::INCLUDE_UNIQUE_ID,
		Tag::BLOB_USAGE_REQUIREMENTS,
		Tag::BOOTLOADER_ONLY,
		Tag::ROLLBACK_RESISTANCE,
		Tag::HARDWARE_TYPE,
		Tag::ACTIVE_DATETIME,
		Tag::ORIGINATION_EXPIRE_DATETIME,
		Tag::USAGE_EXPIRE_DATETIME,
		Tag::MIN_SECONDS_BETWEEN_OPS,
		Tag::MAX_USES_PER_BOOT,
		Tag::USER_ID,
		Tag::USER_SECURE_ID,
		Tag::NO_AUTH_REQUIRED,
		Tag::USER_AUTH_TYPE,
		Tag::AUTH_TIMEOUT,
		Tag::ALLOW_WHILE_ON_BODY,
		Tag::TRUSTED_USER_PRESENCE_REQUIRED,
		Tag::TRUSTED_CONFIRMATION_REQUIRED,
		Tag::UNLOCKED_DEVICE_REQUIRED,
		Tag::APPLICATION_ID,
		Tag::APPLICATION_DATA,
		Tag::CREATION_DATETIME,
		Tag::ORIGIN,
		Tag::ROOT_OF_TRUST,
		Tag::OS_VERSION,
		Tag::OS_PATCHLEVEL,
		Tag::UNIQUE_ID,
		Tag::ATTESTATION_CHALLENGE,
		Tag::ATTESTATION_APPLICATION_ID,
		Tag::ATTESTATION_ID_BRAND,
		Tag::ATTESTATION_ID_DEVICE,
		Tag::ATTESTATION_ID_PRODUCT,
		Tag::ATTESTATION_ID_SERIAL,
		Tag::ATTESTATION_ID_IMEI,
		Tag::ATTESTATION_ID_MEID,
		Tag::ATTESTATION_ID_MANUFACTURER,
		Tag::ATTESTATION_ID_MODEL,
		Tag::VENDOR_PATCHLEVEL,
		Tag::BOOT_PATCHLEVEL,
		Tag::ASSOCIATED_DATA,
		Tag::NONCE,
		Tag::MAC_LENGTH,
		Tag::RESET_SINCE_ID_ROTATION,
		Tag::CONFIRMATION_TOKEN};

		class KeyMaster4AuthSetFuzzer {
		public:
		void process(const uint8_t* data, size_t size);

		private:
		void invokeAuthSetAPIs();
		std::unique_ptr<FuzzedDataProvider> mFdp = nullptr;
		};

		/**
		* @brief invokeAuthSetAPIs() function aims at calling functions of authorization_set.cpp
		* and authorization_set.h in order to get a good coverage for libkeymaster4support.
		*/
		void KeyMaster4AuthSetFuzzer::invokeAuthSetAPIs() {
		AuthorizationSet authSet = createAuthorizationSet(mFdp);
		while (mFdp->remaining_bytes() > 0) {
		uint32_t action = mFdp->ConsumeIntegralInRange<uint32_t>(0, 15);
		switch (action) {
		case 0: {
		authSet.Sort();
		} break;
		case 1: {
		authSet.Deduplicate();
		} break;
		case 2: {
		authSet.Union(createAuthorizationSet(mFdp));
		} break;
		case 3: {
		authSet.Subtract(createAuthorizationSet(mFdp));
		} break;
		case 4: {
		std::filebuf fbOut;
		fbOut.open("/dev/zero", std::ios::out);
		std::ostream out(&fbOut);
		authSet.Serialize(&out);
		} break;
		case 5: {
		std::filebuf fbIn;
		fbIn.open("/dev/zero", std::ios::in);
		std::istream in(&fbIn);
		authSet.Deserialize(&in);
		} break;
		case 6: { // invoke push_back()
		AuthorizationSetBuilder builder = AuthorizationSetBuilder();
		for (const KeyParameter& tag : authSet) {
		builder.push_back(tag);
		}
		AuthorizationSet params = createAuthorizationSet(mFdp);
		authSet.push_back(params);
		} break;
		case 7: { // invoke copy constructor
		auto params = AuthorizationSetBuilder().Authorizations(authSet);
		authSet = params;
		} break;
		case 8: { // invoke move constructor
		auto params = AuthorizationSetBuilder().Authorizations(authSet);
		authSet = std::move(params);
		} break;
		case 9: { // invoke Constructor from hidl_vec<KeyParameter>
		hidl_vec<KeyParameter> keyParam;
		size_t numKeyParam = mFdp->ConsumeIntegralInRange<size_t>(1, kMaxKeyParameter);
		keyParam.resize(numKeyParam);
		for (size_t i = 0; i < numKeyParam - 1; ++i) {
		keyParam[i].tag = mFdp->PickValueInArray(kTagArray);
		std::vector<uint8_t> dataVector = mFdp->ConsumeBytes<uint8_t>(
		mFdp->ConsumeIntegralInRange<size_t>(0, kMaxVectorSize));
		keyParam[i].blob = dataVector;
		}
		if (mFdp->ConsumeBool()) {
		AuthorizationSet auths(keyParam);
		auths.push_back(AuthorizationSet(keyParam));
		} else { // invoke operator=
		AuthorizationSet auths = keyParam;
		}
		} break;
		case 10: { // invoke 'Contains()'
		Tag tag;
		if (authSet.size() > 0) {
		tag = authSet[mFdp->ConsumeIntegralInRange<size_t>(0, authSet.size() - 1)].tag;
		}
		authSet.Contains(mFdp->ConsumeBool() ? tag : mFdp->PickValueInArray(kTagArray));
		} break;
		case 11: { // invoke 'GetTagCount()'
		Tag tag;
		if (authSet.size() > 0) {
		tag = authSet[mFdp->ConsumeIntegralInRange<size_t>(0, authSet.size() - 1)].tag;
		}
		authSet.GetTagCount(mFdp->ConsumeBool() ? tag : mFdp->PickValueInArray(kTagArray));
		} break;
		case 12: { // invoke 'empty()'
		authSet.empty();
		} break;
		case 13: { // invoke 'data()'
		authSet.data();
		} break;
		case 14: { // invoke 'hidl_data()'
		authSet.hidl_data();
		} break;
		case 15: { // invoke 'erase()'
		if (authSet.size() > 0) {
		authSet.erase(mFdp->ConsumeIntegralInRange<size_t>(0, authSet.size() - 1));
		}
		} break;
		default:
		break;
		};
		}
		authSet.Clear();
		}

		void KeyMaster4AuthSetFuzzer::process(const uint8_t* data, size_t size) {
		mFdp = std::make_unique<FuzzedDataProvider>(data, size);
		invokeAuthSetAPIs();
		}

		extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
		KeyMaster4AuthSetFuzzer km4AuthSetFuzzer;
		km4AuthSetFuzzer.process(data, size);
		return 0;
		}

		} // namespace android::hardware::keymaster::V4_0::fuzzer

keymaster/4.0/support/fuzzer/keymaster4_common.h

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