Audio policy: anonymize Bluetooth MAC addresses (24df283a) · Commits · e / os / android_frameworks_av

media/audio/aconfig/audio_flags.aconfig

+9 −0

Original line number	Diff line number	Diff line
		@@ -21,6 +21,15 @@ Enable configurable pre-scale absolute volume."
		bug: "302553525"
		}

		flag {
		name: "bluetooth_mac_address_anonymization"
		namespace: "media_audio"
		description: "\
		Enable Bluetooth MAC address anonymization when reporting \
		audio device descriptors to non privileged apps."
		bug: "285588444"
		}

		flag {
		name: "mutex_priority_inheritance"
		namespace: "media_audio"

media/audioaidlconversion/AidlConversionCppNdk.cpp

+18 −2

Original line number	Diff line number	Diff line
		@@ -1069,6 +1069,13 @@ AudioDeviceAddress::Tag suggestDeviceAddressTag(const AudioDeviceDescription& de
		if (mac.size() != 6) return BAD_VALUE;
		snprintf(addressBuffer, AUDIO_DEVICE_MAX_ADDRESS_LEN, "%02X:%02X:%02X:%02X:%02X:%02X",
		mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);
		// special case for anonymized mac address:
		// change anonymized bytes back from FD:FF:FF:FF to XX:XX:XX:XX
		std::string address(addressBuffer);
		if (address.compare(0, strlen("FD:FF:FF:FF"), "FD:FF:FF:FF") == 0) {
		address.replace(0, strlen("FD:FF:FF:FF"), "XX:XX:XX:XX");
		}
		strcpy(addressBuffer, address.c_str());
		} break;
		case Tag::ipv4: {
		const std::vector<uint8_t>& ipv4 = aidl.address.get<AudioDeviceAddress::ipv4>();
		@@ -1125,11 +1132,20 @@ legacy2aidl_audio_device_AudioDevice(
		if (!legacyAddress.empty()) {
		switch (suggestDeviceAddressTag(aidl.type)) {
		case Tag::mac: {
		// special case for anonymized mac address:
		// change anonymized bytes so that they can be scanned as HEX bytes
		// Use '01' for LSB bits 0 and 1 as Bluetooth MAC addresses are never multicast
		// and universaly administered
		std::string address = legacyAddress;
		if (address.compare(0, strlen("XX:XX:XX:XX"), "XX:XX:XX:XX") == 0) {
		address.replace(0, strlen("XX:XX:XX:XX"), "FD:FF:FF:FF");
		}

		std::vector<uint8_t> mac(6);
		int status = sscanf(legacyAddress.c_str(), "%hhX:%hhX:%hhX:%hhX:%hhX:%hhX",
		int status = sscanf(address.c_str(), "%hhX:%hhX:%hhX:%hhX:%hhX:%hhX",
		&mac[0], &mac[1], &mac[2], &mac[3], &mac[4], &mac[5]);
		if (status != mac.size()) {
		ALOGE("%s: malformed MAC address: \"%s\"", __func__, legacyAddress.c_str());
		ALOGE("%s: malformed MAC address: \"%s\"", __func__, address.c_str());
		return unexpected(BAD_VALUE);
		}
		aidl.address = AudioDeviceAddress::make<AudioDeviceAddress::mac>(std::move(mac));

media/libaudioclient/tests/audio_aidl_legacy_conversion_tests.cpp

+20 −0

Original line number	Diff line number	Diff line
		@@ -481,8 +481,28 @@ INSTANTIATE_TEST_SUITE_P(
		AudioDeviceAddress::make<AudioDeviceAddress::Tag::alsa>(
		std::vector<int32_t>{1, 2}))));

		TEST(AnonymizedBluetoothAddressRoundTripTest, Legacy2Aidl2Legacy) {
		const std::vector<uint8_t> sAnonymizedAidlAddress =
		std::vector<uint8_t>{0xFD, 0xFF, 0xFF, 0xFF, 0xAB, 0xCD};
		const std::string sAnonymizedLegacyAddress = std::string("XX:XX:XX:XX:AB:CD");
		auto device = legacy2aidl_audio_device_AudioDevice(AUDIO_DEVICE_OUT_BLUETOOTH_A2DP,
		sAnonymizedLegacyAddress);
		ASSERT_TRUE(device.ok());
		ASSERT_EQ(AudioDeviceAddress::Tag::mac, device.value().address.getTag());
		ASSERT_EQ(sAnonymizedAidlAddress, device.value().address.get<AudioDeviceAddress::mac>());

		audio_devices_t legacyType;
		std::string legacyAddress;
		status_t status =
		aidl2legacy_AudioDevice_audio_device(device.value(), &legacyType, &legacyAddress);
		ASSERT_EQ(OK, status);
		EXPECT_EQ(legacyType, AUDIO_DEVICE_OUT_BLUETOOTH_A2DP);
		EXPECT_EQ(sAnonymizedLegacyAddress, legacyAddress);
		}

		class AudioFormatDescriptionRoundTripTest : public testing::TestWithParam<AudioFormatDescription> {
		};

		TEST_P(AudioFormatDescriptionRoundTripTest, Aidl2Legacy2Aidl) {
		const auto initial = GetParam();
		auto conv = aidl2legacy_AudioFormatDescription_audio_format_t(initial);

media/utils/Android.bp

+1 −0

Original line number	Diff line number	Diff line
		@@ -93,6 +93,7 @@ cc_library {
		"liblog",
		"libpermission",
		"libutils",
		"aconfig_audio_flags_c_lib",
		"android.hardware.graphics.bufferqueue@1.0",
		"android.hidl.token@1.0-utils",
		"packagemanager_aidl-cpp",

media/utils/ServiceUtilities.cpp

+48 −0

Original line number	Diff line number	Diff line
		@@ -27,6 +27,7 @@
		#include <media/AidlConversionUtil.h>
		#include <android/content/AttributionSourceState.h>

		#include <com_android_media_audio_flags.h>
		#include <iterator>
		#include <algorithm>
		#include <pwd.h>
		@@ -46,6 +47,7 @@ static const String16 sAndroidPermissionRecordAudio("android.permission.RECORD_A
		static const String16 sModifyPhoneState("android.permission.MODIFY_PHONE_STATE");
		static const String16 sModifyAudioRouting("android.permission.MODIFY_AUDIO_ROUTING");
		static const String16 sCallAudioInterception("android.permission.CALL_AUDIO_INTERCEPTION");
		static const String16 sAndroidPermissionBluetoothConnect("android.permission.BLUETOOTH_CONNECT");

		static String16 resolveCallingPackage(PermissionController& permissionController,
		const std::optional<String16> opPackageName, uid_t uid) {
		@@ -374,6 +376,52 @@ status_t checkIMemory(const sp<IMemory>& iMemory)
		return NO_ERROR;
		}

		/**
		* Determines if the MAC address in Bluetooth device descriptors returned by APIs of
		* a native audio service (audio flinger, audio policy) must be anonymized.
		* MAC addresses returned to system server or apps with BLUETOOTH_CONNECT permission
		* are not anonymized.
		*
		* @param attributionSource The attribution source of the calling app.
		* @param caller string identifying the caller for logging.
		* @return true if the MAC addresses must be anonymized, false otherwise.
		*/
		bool mustAnonymizeBluetoothAddress(
		const AttributionSourceState& attributionSource, const String16& caller) {
		if (!com::android::media::audio::flags::bluetooth_mac_address_anonymization()) {
		return false;
		}

		uid_t uid = VALUE_OR_FATAL(aidl2legacy_int32_t_uid_t(attributionSource.uid));
		if (isAudioServerOrSystemServerUid(uid)) {
		return false;
		}
		const std::optional<AttributionSourceState> resolvedAttributionSource =
		resolveAttributionSource(attributionSource);
		if (!resolvedAttributionSource.has_value()) {
		return true;
		}
		permission::PermissionChecker permissionChecker;
		return permissionChecker.checkPermissionForPreflightFromDatasource(
		sAndroidPermissionBluetoothConnect, resolvedAttributionSource.value(), caller,
		AppOpsManager::OP_BLUETOOTH_CONNECT)
		!= permission::PermissionChecker::PERMISSION_GRANTED;
		}

		/**
		* Modifies the passed MAC address string in place for consumption by unprivileged clients.
		* the string is assumed to have a valid MAC address format.
		* the anonymzation must be kept in sync with toAnonymizedAddress() in BluetoothUtils.java
		*
		* @param address input/output the char string contining the MAC address to anonymize.
		*/
		void anonymizeBluetoothAddress(char *address) {
		if (address == nullptr \|\| strlen(address) != strlen("AA:BB:CC:DD:EE:FF")) {
		return;
		}
		memcpy(address, "XX:XX:XX:XX", strlen("XX:XX:XX:XX"));
		}

		sp<content::pm::IPackageManagerNative> MediaPackageManager::retrievePackageManager() {
		const sp<IServiceManager> sm = defaultServiceManager();
		if (sm == nullptr) {