Fix memory flags in external services and secondary zygotes. (fe85ed2e) · Commits · e / os / android_frameworks_base

core/java/android/os/AppZygote.java

+9 −6

Original line number	Diff line number	Diff line
		@@ -17,9 +17,11 @@
		package android.os;

		import android.content.pm.ApplicationInfo;
		import android.content.pm.ProcessInfo;
		import android.util.Log;

		import com.android.internal.annotations.GuardedBy;
		import com.android.internal.os.Zygote;

		import dalvik.system.VMRuntime;

		@@ -45,8 +47,6 @@ public class AppZygote {
		// Last UID/GID of the range the AppZygote can setuid()/setgid() to
		private final int mZygoteUidGidMax;

		private final int mZygoteRuntimeFlags;

		private final Object mLock = new Object();

		/**
		@@ -57,14 +57,15 @@ public class AppZygote {
		private ChildZygoteProcess mZygote;

		private final ApplicationInfo mAppInfo;
		private final ProcessInfo mProcessInfo;

		public AppZygote(ApplicationInfo appInfo, int zygoteUid, int uidGidMin, int uidGidMax,
		int runtimeFlags) {
		public AppZygote(ApplicationInfo appInfo, ProcessInfo processInfo, int zygoteUid, int uidGidMin,
		int uidGidMax) {
		mAppInfo = appInfo;
		mProcessInfo = processInfo;
		mZygoteUid = zygoteUid;
		mZygoteUidGidMin = uidGidMin;
		mZygoteUidGidMax = uidGidMax;
		mZygoteRuntimeFlags = runtimeFlags;
		}

		/**
		@@ -108,13 +109,15 @@ public class AppZygote {
		String abi = mAppInfo.primaryCpuAbi != null ? mAppInfo.primaryCpuAbi :
		Build.SUPPORTED_ABIS[0];
		try {
		int runtimeFlags = Zygote.getMemorySafetyRuntimeFlagsForSecondaryZygote(
		mAppInfo, mProcessInfo);
		mZygote = Process.ZYGOTE_PROCESS.startChildZygote(
		"com.android.internal.os.AppZygoteInit",
		mAppInfo.processName + "_zygote",
		mZygoteUid,
		mZygoteUid,
		null, // gids
		mZygoteRuntimeFlags, // runtimeFlags
		runtimeFlags,
		"app_zygote", // seInfo
		abi, // abi
		abi, // acceptedAbiList

core/java/android/webkit/WebViewZygote.java

+4 −1

Original line number	Diff line number	Diff line
		@@ -25,6 +25,7 @@ import android.text.TextUtils;
		import android.util.Log;

		import com.android.internal.annotations.GuardedBy;
		import com.android.internal.os.Zygote;

		/** @hide */
		public class WebViewZygote {
		@@ -127,13 +128,15 @@ public class WebViewZygote {

		try {
		String abi = sPackage.applicationInfo.primaryCpuAbi;
		int runtimeFlags = Zygote.getMemorySafetyRuntimeFlagsForSecondaryZygote(
		sPackage.applicationInfo, null);
		sZygote = Process.ZYGOTE_PROCESS.startChildZygote(
		"com.android.internal.os.WebViewZygoteInit",
		"webview_zygote",
		Process.WEBVIEW_ZYGOTE_UID,
		Process.WEBVIEW_ZYGOTE_UID,
		null, // gids
		0, // runtimeFlags
		runtimeFlags,
		"webview_zygote", // seInfo
		abi, // abi
		TextUtils.join(",", Build.SUPPORTED_ABIS),

core/java/com/android/internal/os/Zygote.java

+259 −4

Original line number	Diff line number	Diff line
		@@ -20,13 +20,21 @@ import static android.system.OsConstants.O_CLOEXEC;

		import android.annotation.NonNull;
		import android.annotation.Nullable;
		import android.compat.annotation.ChangeId;
		import android.compat.annotation.Disabled;
		import android.compat.annotation.EnabledAfter;
		import android.content.Context;
		import android.content.pm.ApplicationInfo;
		import android.content.pm.ProcessInfo;
		import android.net.Credentials;
		import android.net.LocalServerSocket;
		import android.net.LocalSocket;
		import android.os.Build;
		import android.os.FactoryTest;
		import android.os.IVold;
		import android.os.Process;
		import android.os.RemoteException;
		import android.os.ServiceManager;
		import android.os.SystemProperties;
		import android.os.Trace;
		import android.provider.DeviceConfig;
		@@ -34,6 +42,7 @@ import android.system.ErrnoException;
		import android.system.Os;
		import android.util.Log;

		import com.android.internal.compat.IPlatformCompat;
		import com.android.internal.net.NetworkUtilsInternal;

		import dalvik.annotation.optimization.CriticalNative;
		@@ -125,6 +134,7 @@ public final class Zygote {
		public static final int MEMORY_TAG_LEVEL_MASK = (1 << 19) \| (1 << 20);

		public static final int MEMORY_TAG_LEVEL_NONE = 0;

		/**
		* Enable pointer tagging in this process.
		* Tags are checked during memory deallocation, but not on access.
		@@ -170,10 +180,8 @@ public final class Zygote {
		*/
		public static final int GWP_ASAN_LEVEL_ALWAYS = 1 << 22;

		/**
		* Enable automatic zero-initialization of native heap memory allocations.
		*/
		public static final int NATIVE_HEAP_ZERO_INIT = 1 << 23;
		/** Enable automatic zero-initialization of native heap memory allocations. */
		public static final int NATIVE_HEAP_ZERO_INIT_ENABLED = 1 << 23;

		/**
		* Enable profiling from system services. This loads profiling related plugins in ART.
		@@ -1170,4 +1178,251 @@ public final class Zygote {
		* we failed to determine the level.
		*/
		public static native int nativeCurrentTaggingLevel();

		/**
		* Native heap allocations will now have a non-zero tag in the most significant byte.
		*
		* @see <a href="https://source.android.com/devices/tech/debug/tagged-pointers">Tagged
		* Pointers</a>
		*/
		@ChangeId
		@EnabledAfter(targetSdkVersion = Build.VERSION_CODES.Q)
		private static final long NATIVE_HEAP_POINTER_TAGGING = 135754954; // This is a bug id.

		/**
		* Native heap allocations in AppZygote process and its descendants will now have a non-zero tag
		* in the most significant byte.
		*
		* @see <a href="https://source.android.com/devices/tech/debug/tagged-pointers">Tagged
		* Pointers</a>
		*/
		@ChangeId
		@EnabledAfter(targetSdkVersion = Build.VERSION_CODES.S)
		private static final long NATIVE_HEAP_POINTER_TAGGING_SECONDARY_ZYGOTE = 207557677;

		/**
		* Enable asynchronous (ASYNC) memory tag checking in this process. This flag will only have an
		* effect on hardware supporting the ARM Memory Tagging Extension (MTE).
		*/
		@ChangeId @Disabled
		private static final long NATIVE_MEMTAG_ASYNC = 135772972; // This is a bug id.

		/**
		* Enable synchronous (SYNC) memory tag checking in this process. This flag will only have an
		* effect on hardware supporting the ARM Memory Tagging Extension (MTE). If both
		* NATIVE_MEMTAG_ASYNC and this option is selected, this option takes preference and MTE is
		* enabled in SYNC mode.
		*/
		@ChangeId @Disabled
		private static final long NATIVE_MEMTAG_SYNC = 177438394; // This is a bug id.

		/** Enable automatic zero-initialization of native heap memory allocations. */
		@ChangeId @Disabled
		private static final long NATIVE_HEAP_ZERO_INIT = 178038272; // This is a bug id.

		/**
		* Enable sampled memory bug detection in the app.
		*
		* @see <a href="https://source.android.com/devices/tech/debug/gwp-asan">GWP-ASan</a>.
		*/
		@ChangeId @Disabled private static final long GWP_ASAN = 135634846; // This is a bug id.

		private static int memtagModeToZygoteMemtagLevel(int memtagMode) {
		switch (memtagMode) {
		case ApplicationInfo.MEMTAG_ASYNC:
		return MEMORY_TAG_LEVEL_ASYNC;
		case ApplicationInfo.MEMTAG_SYNC:
		return MEMORY_TAG_LEVEL_SYNC;
		default:
		return MEMORY_TAG_LEVEL_NONE;
		}
		}

		private static boolean isCompatChangeEnabled(
		long change,
		@NonNull ApplicationInfo info,
		@Nullable IPlatformCompat platformCompat,
		int enabledAfter) {
		try {
		if (platformCompat != null) return platformCompat.isChangeEnabled(change, info);
		} catch (RemoteException ignore) {
		}
		return enabledAfter > 0 && info.targetSdkVersion > enabledAfter;
		}

		// Returns the requested memory tagging level.
		private static int getRequestedMemtagLevel(
		@NonNull ApplicationInfo info,
		@Nullable ProcessInfo processInfo,
		@Nullable IPlatformCompat platformCompat) {
		// Look at the process attribute first.
		if (processInfo != null && processInfo.memtagMode != ApplicationInfo.MEMTAG_DEFAULT) {
		return memtagModeToZygoteMemtagLevel(processInfo.memtagMode);
		}

		// Then at the application attribute.
		if (info.getMemtagMode() != ApplicationInfo.MEMTAG_DEFAULT) {
		return memtagModeToZygoteMemtagLevel(info.getMemtagMode());
		}

		if (isCompatChangeEnabled(NATIVE_MEMTAG_SYNC, info, platformCompat, 0)) {
		return MEMORY_TAG_LEVEL_SYNC;
		}

		if (isCompatChangeEnabled(NATIVE_MEMTAG_ASYNC, info, platformCompat, 0)) {
		return MEMORY_TAG_LEVEL_ASYNC;
		}

		// Check to ensure the app hasn't explicitly opted-out of TBI via. the manifest attribute.
		if (!info.allowsNativeHeapPointerTagging()) {
		return MEMORY_TAG_LEVEL_NONE;
		}

		String defaultLevel = SystemProperties.get("persist.arm64.memtag.app_default");
		if ("sync".equals(defaultLevel)) {
		return MEMORY_TAG_LEVEL_SYNC;
		} else if ("async".equals(defaultLevel)) {
		return MEMORY_TAG_LEVEL_ASYNC;
		}

		// Check to see that the compat feature for TBI is enabled.
		if (isCompatChangeEnabled(
		NATIVE_HEAP_POINTER_TAGGING, info, platformCompat, Build.VERSION_CODES.Q)) {
		return MEMORY_TAG_LEVEL_TBI;
		}

		return MEMORY_TAG_LEVEL_NONE;
		}

		private static int decideTaggingLevel(
		@NonNull ApplicationInfo info,
		@Nullable ProcessInfo processInfo,
		@Nullable IPlatformCompat platformCompat) {
		// Get the desired tagging level (app manifest + compat features).
		int level = getRequestedMemtagLevel(info, processInfo, platformCompat);

		// Take into account the hardware capabilities.
		if (nativeSupportsMemoryTagging()) {
		// MTE devices can not do TBI, because the Zygote process already has live MTE
		// allocations. Downgrade TBI to NONE.
		if (level == MEMORY_TAG_LEVEL_TBI) {
		level = MEMORY_TAG_LEVEL_NONE;
		}
		} else if (nativeSupportsTaggedPointers()) {
		// TBI-but-not-MTE devices downgrade MTE modes to TBI.
		// The idea is that if an app opts into full hardware tagging (MTE), it must be ok with
		// the "fake" pointer tagging (TBI).
		if (level == MEMORY_TAG_LEVEL_ASYNC \|\| level == MEMORY_TAG_LEVEL_SYNC) {
		level = MEMORY_TAG_LEVEL_TBI;
		}
		} else {
		// Otherwise disable all tagging.
		level = MEMORY_TAG_LEVEL_NONE;
		}

		return level;
		}

		private static int decideGwpAsanLevel(
		@NonNull ApplicationInfo info,
		@Nullable ProcessInfo processInfo,
		@Nullable IPlatformCompat platformCompat) {
		// Look at the process attribute first.
		if (processInfo != null && processInfo.gwpAsanMode != ApplicationInfo.GWP_ASAN_DEFAULT) {
		return processInfo.gwpAsanMode == ApplicationInfo.GWP_ASAN_ALWAYS
		? GWP_ASAN_LEVEL_ALWAYS
		: GWP_ASAN_LEVEL_NEVER;
		}
		// Then at the application attribute.
		if (info.getGwpAsanMode() != ApplicationInfo.GWP_ASAN_DEFAULT) {
		return info.getGwpAsanMode() == ApplicationInfo.GWP_ASAN_ALWAYS
		? GWP_ASAN_LEVEL_ALWAYS
		: GWP_ASAN_LEVEL_NEVER;
		}
		// If the app does not specify gwpAsanMode, the default behavior is lottery among the
		// system apps, and disabled for user apps, unless overwritten by the compat feature.
		if (isCompatChangeEnabled(GWP_ASAN, info, platformCompat, 0)) {
		return GWP_ASAN_LEVEL_ALWAYS;
		}
		if ((info.flags & ApplicationInfo.FLAG_SYSTEM) != 0) {
		return GWP_ASAN_LEVEL_LOTTERY;
		}
		return GWP_ASAN_LEVEL_NEVER;
		}

		private static boolean enableNativeHeapZeroInit(
		@NonNull ApplicationInfo info,
		@Nullable ProcessInfo processInfo,
		@Nullable IPlatformCompat platformCompat) {
		// Look at the process attribute first.
		if (processInfo != null
		&& processInfo.nativeHeapZeroInitialized != ApplicationInfo.ZEROINIT_DEFAULT) {
		return processInfo.nativeHeapZeroInitialized == ApplicationInfo.ZEROINIT_ENABLED;
		}
		// Then at the application attribute.
		if (info.getNativeHeapZeroInitialized() != ApplicationInfo.ZEROINIT_DEFAULT) {
		return info.getNativeHeapZeroInitialized() == ApplicationInfo.ZEROINIT_ENABLED;
		}
		// Compat feature last.
		if (isCompatChangeEnabled(NATIVE_HEAP_ZERO_INIT, info, platformCompat, 0)) {
		return true;
		}
		return false;
		}

		/**
		* Returns Zygote runtimeFlags for memory safety features (MTE, GWP-ASan, nativeHeadZeroInit)
		* for a given app.
		*/
		public static int getMemorySafetyRuntimeFlags(
		@NonNull ApplicationInfo info,
		@Nullable ProcessInfo processInfo,
		@Nullable String instructionSet,
		@Nullable IPlatformCompat platformCompat) {
		int runtimeFlags = decideGwpAsanLevel(info, processInfo, platformCompat);
		// If instructionSet is non-null, this indicates that the system_server is spawning a
		// process with an ISA that may be different from its own. System (kernel and hardware)
		// compatibility for these features is checked in the decideTaggingLevel in the
		// system_server process (not the child process). As both MTE and TBI are only supported
		// in aarch64, we can simply ensure that the new process is also aarch64. This prevents
		// the mismatch where a 64-bit system server spawns a 32-bit child that thinks it should
		// enable some tagging variant. Theoretically, a 32-bit system server could exist that
		// spawns 64-bit processes, in which case the new process won't get any tagging. This is
		// fine as we haven't seen this configuration in practice, and we can reasonable assume
		// that if tagging is desired, the system server will be 64-bit.
		if (instructionSet == null \|\| instructionSet.equals("arm64")) {
		runtimeFlags \|= decideTaggingLevel(info, processInfo, platformCompat);
		}
		if (enableNativeHeapZeroInit(info, processInfo, platformCompat)) {
		runtimeFlags \|= NATIVE_HEAP_ZERO_INIT_ENABLED;
		}
		return runtimeFlags;
		}

		/**
		* Returns Zygote runtimeFlags for memory safety features (MTE, GWP-ASan, nativeHeadZeroInit)
		* for a secondary zygote (AppZygote or WebViewZygote).
		*/
		public static int getMemorySafetyRuntimeFlagsForSecondaryZygote(
		@NonNull ApplicationInfo info, @Nullable ProcessInfo processInfo) {
		final IPlatformCompat platformCompat =
		IPlatformCompat.Stub.asInterface(
		ServiceManager.getService(Context.PLATFORM_COMPAT_SERVICE));
		int runtimeFlags =
		getMemorySafetyRuntimeFlags(
		info, processInfo, null /instructionSet/, platformCompat);

		// TBI ("fake" pointer tagging) in AppZygote is controlled by a separate compat feature.
		if ((runtimeFlags & MEMORY_TAG_LEVEL_MASK) == MEMORY_TAG_LEVEL_TBI
		&& isCompatChangeEnabled(
		NATIVE_HEAP_POINTER_TAGGING_SECONDARY_ZYGOTE,
		info,
		platformCompat,
		Build.VERSION_CODES.S)) {
		// Reset memory tag level to NONE.
		runtimeFlags &= ~MEMORY_TAG_LEVEL_MASK;
		runtimeFlags \|= MEMORY_TAG_LEVEL_NONE;
		}
		return runtimeFlags;
		}
		}

core/jni/com_android_internal_os_Zygote.cpp

+3 −3

Original line number	Diff line number	Diff line
		@@ -346,7 +346,7 @@ enum RuntimeFlags : uint32_t {
		GWP_ASAN_LEVEL_NEVER = 0 << 21,
		GWP_ASAN_LEVEL_LOTTERY = 1 << 21,
		GWP_ASAN_LEVEL_ALWAYS = 2 << 21,
		NATIVE_HEAP_ZERO_INIT = 1 << 23,
		NATIVE_HEAP_ZERO_INIT_ENABLED = 1 << 23,
		PROFILEABLE = 1 << 24,
		};

		@@ -1709,13 +1709,13 @@ static void SpecializeCommon(JNIEnv* env, uid_t uid, gid_t gid, jintArray gids,
		// would be nice to have them for apps, we will have to wait until they are
		// proven out, have more efficient hardware, and/or apply them only to new
		// applications.
		if (!(runtime_flags & RuntimeFlags::NATIVE_HEAP_ZERO_INIT)) {
		if (!(runtime_flags & RuntimeFlags::NATIVE_HEAP_ZERO_INIT_ENABLED)) {
		mallopt(M_BIONIC_ZERO_INIT, 0);
		}

		// Now that we've used the flag, clear it so that we don't pass unknown flags to the ART
		// runtime.
		runtime_flags &= ~RuntimeFlags::NATIVE_HEAP_ZERO_INIT;
		runtime_flags &= ~RuntimeFlags::NATIVE_HEAP_ZERO_INIT_ENABLED;

		bool forceEnableGwpAsan = false;
		switch (runtime_flags & RuntimeFlags::GWP_ASAN_LEVEL_MASK) {

services/core/java/com/android/server/am/ActiveServices.java

+5 −3

Original line number	Diff line number	Diff line
		@@ -4139,7 +4139,8 @@ public final class ActiveServices {

		final boolean isolated = (r.serviceInfo.flags&ServiceInfo.FLAG_ISOLATED_PROCESS) != 0;
		final String procName = r.processName;
		HostingRecord hostingRecord = new HostingRecord("service", r.instanceName);
		HostingRecord hostingRecord = new HostingRecord("service", r.instanceName,
		r.definingPackageName, r.definingUid, r.serviceInfo.processName);
		ProcessRecord app;

		if (!isolated) {
		@@ -4177,11 +4178,12 @@ public final class ActiveServices {
		app = r.isolationHostProc;
		if (WebViewZygote.isMultiprocessEnabled()
		&& r.serviceInfo.packageName.equals(WebViewZygote.getPackageName())) {
		hostingRecord = HostingRecord.byWebviewZygote(r.instanceName);
		hostingRecord = HostingRecord.byWebviewZygote(r.instanceName, r.definingPackageName,
		r.definingUid, r.serviceInfo.processName);
		}
		if ((r.serviceInfo.flags & ServiceInfo.FLAG_USE_APP_ZYGOTE) != 0) {
		hostingRecord = HostingRecord.byAppZygote(r.instanceName, r.definingPackageName,
		r.definingUid);
		r.definingUid, r.serviceInfo.processName);
		}
		}