Merge "Add lower bound checks for non-manual time suggestions." am: 7d0a2d7970 (6c393856) · Commits · e / os / android_frameworks_base

services/core/java/com/android/server/timedetector/TimeDetectorStrategyCallbackImpl.java

+15 −0

Original line number	Diff line number	Diff line
		@@ -20,12 +20,15 @@ import android.annotation.NonNull;
		import android.app.AlarmManager;
		import android.content.ContentResolver;
		import android.content.Context;
		import android.os.Build;
		import android.os.Environment;
		import android.os.PowerManager;
		import android.os.SystemClock;
		import android.os.SystemProperties;
		import android.provider.Settings;
		import android.util.Slog;

		import java.time.Instant;
		import java.util.Objects;

		/**
		@@ -37,6 +40,13 @@ public final class TimeDetectorStrategyCallbackImpl implements TimeDetectorStrat

		private static final int SYSTEM_CLOCK_UPDATE_THRESHOLD_MILLIS_DEFAULT = 2 * 1000;

		/**
		* Time in the past. If automatic time suggestion is before this point, it's
		* incorrect for sure.
		*/
		private static final Instant TIME_LOWER_BOUND = Instant.ofEpochMilli(
		Long.max(Environment.getRootDirectory().lastModified(), Build.TIME));

		/**
		* If a newly calculated system clock time and the current system clock time differs by this or
		* more the system clock will actually be updated. Used to prevent the system clock being set
		@@ -78,6 +88,11 @@ public final class TimeDetectorStrategyCallbackImpl implements TimeDetectorStrat
		}
		}

		@Override
		public Instant autoTimeLowerBound() {
		return TIME_LOWER_BOUND;
		}

		@Override
		public void acquireWakeLock() {
		if (mWakeLock.isHeld()) {

services/core/java/com/android/server/timedetector/TimeDetectorStrategyImpl.java

+38 −10

Original line number	Diff line number	Diff line
		@@ -36,6 +36,7 @@ import com.android.server.timezonedetector.ReferenceWithHistory;
		import java.io.PrintWriter;
		import java.lang.annotation.Retention;
		import java.lang.annotation.RetentionPolicy;
		import java.time.Instant;

		/**
		* An implementation of {@link TimeDetectorStrategy} that passes telephony and manual suggestions to
		@@ -143,6 +144,15 @@ public final class TimeDetectorStrategyImpl implements TimeDetectorStrategy {
		/** Returns true if automatic time detection is enabled. */
		boolean isAutoTimeDetectionEnabled();

		/**
		* Returns a lower bound for valid automatic times. It is guaranteed to be in the past,
		* i.e. it is unrelated to the current system clock time.
		* It holds no other meaning; it could be related to when the device system image was built,
		* or could be updated by a mainline module.
		*/
		@NonNull
		Instant autoTimeLowerBound();

		/** Acquire a suitable wake lock. Must be followed by {@link #releaseWakeLock()} */
		void acquireWakeLock();

		@@ -177,7 +187,7 @@ public final class TimeDetectorStrategyImpl implements TimeDetectorStrategy {

		@Override
		public synchronized void suggestNetworkTime(@NonNull NetworkTimeSuggestion timeSuggestion) {
		if (!validateSuggestionTime(timeSuggestion.getUtcTime(), timeSuggestion)) {
		if (!validateAutoSuggestionTime(timeSuggestion.getUtcTime(), timeSuggestion)) {
		return;
		}

		@@ -211,9 +221,12 @@ public final class TimeDetectorStrategyImpl implements TimeDetectorStrategy {
		return;
		}

		// Perform validation / input filtering and record the validated suggestion against the
		// slotIndex.
		if (!validateAndStoreTelephonySuggestion(timeSuggestion)) {
		if (!validateAutoSuggestionTime(timeSuggestion.getUtcTime(), timeSuggestion)) {
		return;
		}

		// Perform input filtering and record the validated suggestion against the slotIndex.
		if (!storeTelephonySuggestion(timeSuggestion)) {
		return;
		}

		@@ -272,14 +285,9 @@ public final class TimeDetectorStrategyImpl implements TimeDetectorStrategy {
		}

		@GuardedBy("this")
		private boolean validateAndStoreTelephonySuggestion(
		private boolean storeTelephonySuggestion(
		@NonNull TelephonyTimeSuggestion suggestion) {
		TimestampedValue<Long> newUtcTime = suggestion.getUtcTime();
		if (!validateSuggestionTime(newUtcTime, suggestion)) {
		// There's probably nothing useful we can do: elsewhere we assume that reference
		// times are in the past so just stop here.
		return false;
		}

		int slotIndex = suggestion.getSlotIndex();
		TelephonyTimeSuggestion previousSuggestion = mSuggestionBySlotIndex.get(slotIndex);
		@@ -330,6 +338,26 @@ public final class TimeDetectorStrategyImpl implements TimeDetectorStrategy {
		return true;
		}

		private boolean validateAutoSuggestionTime(
		@NonNull TimestampedValue<Long> newUtcTime, @NonNull Object suggestion) {
		return validateSuggestionTime(newUtcTime, suggestion)
		&& validateSuggestionAgainstLowerBound(newUtcTime, suggestion);
		}

		private boolean validateSuggestionAgainstLowerBound(
		@NonNull TimestampedValue<Long> newUtcTime, @NonNull Object suggestion) {
		Instant lowerBound = mCallback.autoTimeLowerBound();

		// Suggestion is definitely wrong if it comes before lower time bound.
		if (lowerBound.isAfter(Instant.ofEpochMilli(newUtcTime.getValue()))) {
		Slog.w(LOG_TAG, "Suggestion points to time before lower bound, skipping it. "
		+ "suggestion=" + suggestion + ", lower bound=" + lowerBound);
		return false;
		}

		return true;
		}

		@GuardedBy("this")
		private void doAutoTimeDetection(@NonNull String detectionReason) {
		if (!mCallback.isAutoTimeDetectionEnabled()) {

services/tests/servicestests/src/com/android/server/timedetector/TimeDetectorStrategyImplTest.java

+132 −57

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