Fix crash when receiving call with no corresponding identity key.

app/src/main/java/org/thoughtcrime/securesms/WebRtcCallActivity.java

@@ -518,6 +518,7 @@ public class WebRtcCallActivity extends BaseActivity implements SafetyNumberChan
     final Recipient   recipient = event.getRemoteParticipants().get(0).getRecipient();
 
     if (theirKey == null) {
+      Log.w(TAG, "Untrusted identity without an identity key, terminating call.");
       handleTerminate(recipient, HangupMessage.Type.NORMAL);
     }
 

app/src/main/java/org/thoughtcrime/securesms/crypto/IdentityKeyParcelable.java

@@ -19,6 +19,9 @@ package org.thoughtcrime.securesms.crypto;
 import android.os.Parcel;
 import android.os.Parcelable;
 
+import androidx.annotation.Nullable;
+
+import org.thoughtcrime.securesms.util.ParcelUtil;
 import org.whispersystems.libsignal.IdentityKey;
 import org.whispersystems.libsignal.InvalidKeyException;
 
@@ -40,19 +43,17 @@ public class IdentityKeyParcelable implements Parcelable {
 
   private final IdentityKey identityKey;
 
-  public IdentityKeyParcelable(IdentityKey identityKey) {
+  public IdentityKeyParcelable(@Nullable IdentityKey identityKey) {
     this.identityKey = identityKey;
   }
 
   public IdentityKeyParcelable(Parcel in) throws InvalidKeyException {
-    int    serializedLength = in.readInt();
-    byte[] serialized       = new byte[serializedLength];
+    byte[] serialized = ParcelUtil.readByteArray(in);
 
-    in.readByteArray(serialized);
-    this.identityKey = new IdentityKey(serialized, 0);
+    this.identityKey = serialized != null ? new IdentityKey(serialized, 0) : null;
   }
 
-  public IdentityKey get() {
+  public @Nullable IdentityKey get() {
     return identityKey;
   }
 
@@ -63,7 +64,6 @@ public class IdentityKeyParcelable implements Parcelable {
 
   @Override
   public void writeToParcel(Parcel dest, int flags) {
-    dest.writeInt(identityKey.serialize().length);
-    dest.writeByteArray(identityKey.serialize());
+    ParcelUtil.writeByteArray(dest, identityKey != null ? identityKey.serialize() : null);
   }
 }

app/src/main/java/org/thoughtcrime/securesms/events/CallParticipant.java

@@ -85,7 +85,7 @@ public final class CallParticipant {
     this.deviceOrdinal     = deviceOrdinal;
   }
 
-  public @NonNull CallParticipant withIdentityKey(@NonNull IdentityKey identityKey) {
+  public @NonNull CallParticipant withIdentityKey(@Nullable IdentityKey identityKey) {
     return new CallParticipant(callParticipantId, recipient, identityKey, videoSink, cameraState, videoEnabled, microphoneEnabled, lastSpoke, mediaKeysReceived, addedToCallTime, deviceOrdinal);
   }
 

app/src/main/java/org/thoughtcrime/securesms/service/webrtc/WebRtcActionProcessor.java

@@ -533,7 +533,7 @@ public abstract class WebRtcActionProcessor {
 
     if (errorCallState == WebRtcViewModel.State.UNTRUSTED_IDENTITY) {
       CallParticipant participant = Objects.requireNonNull(currentState.getCallInfoState().getRemoteCallParticipant(activePeer.getRecipient()));
-      CallParticipant untrusted   = participant.withIdentityKey(identityKey.get());
+      CallParticipant untrusted   = participant.withIdentityKey(identityKey.orNull());
 
       builder.changeCallInfoState()
              .callState(WebRtcViewModel.State.UNTRUSTED_IDENTITY)

app/src/main/java/org/thoughtcrime/securesms/util/ParcelUtil.java

@@ -4,6 +4,7 @@ import android.os.Parcel;
 import android.os.Parcelable;
 
 import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -59,4 +60,23 @@ public class ParcelUtil {
   public static boolean readBoolean(@NonNull Parcel in) {
     return in.readByte() != 0;
   }
+
+  public static void writeByteArray(@NonNull Parcel dest, @Nullable byte[] data) {
+    if (data == null) {
+      dest.writeInt(-1);
+    } else {
+      dest.writeInt(data.length);
+      dest.writeByteArray(data);
+    }
+  }
+
+  public static @Nullable byte[] readByteArray(@NonNull Parcel in) {
+    int length = in.readInt();
+    if (length == -1) {
+      return null;
+    }
+    byte[] data = new byte[length];
+    in.readByteArray(data);
+    return data;
+  }
 }