[BUGFIX] Validate Entry.receiversPubKey for MailboxPayloads

The remove code checks to ensure these fields match, but the add code
never did. This could lead to a situation where a MailboxStoragePayload
could be added, but never removed.

p2p/src/main/java/bisq/network/p2p/storage/payload/ProtectedMailboxStorageEntry.java

@@ -94,6 +94,13 @@ public boolean isValidForAddOperation() {
             return false;
 
         MailboxStoragePayload mailboxStoragePayload = this.getMailboxStoragePayload();
+
+        // Verify the Entry.receiversPubKey matches the Payload.ownerPubKey. This is a requirement for removal
+        if (!mailboxStoragePayload.getOwnerPubKey().equals(this.receiversPubKey)) {
+            log.debug("Entry receiversPubKey does not match payload owner which is a requirement for adding MailboxStoragePayloads");
+            return false;
+        }
+
         boolean result = mailboxStoragePayload.getSenderPubKeyForAddOperation() != null &&
                 mailboxStoragePayload.getSenderPubKeyForAddOperation().equals(this.getOwnerPubKey());
 

p2p/src/test/java/bisq/network/p2p/storage/payload/ProtectedMailboxStorageEntryTest.java

@@ -94,8 +94,6 @@ public void isValidForAddOperation_EntryOwnerPayloadReceiverMismatch() throws No
     }
 
     // TESTCASE: validForAddOperation() should fail if Entry.receiversPubKey and Payload.ownerPubKey don't match
-    // XXXBUGXXX: The current code doesn't validate this mismatch, but it would create an added payload that could never
-    // be removed since the remove code requires Entry.receiversPubKey == Payload.ownerPubKey
     @Test
     public void isValidForAddOperation_EntryReceiverPayloadReceiverMismatch() throws NoSuchAlgorithmException, CryptoException {
         KeyPair senderKeys = TestUtils.generateKeyPair();
@@ -104,8 +102,7 @@ public void isValidForAddOperation_EntryReceiverPayloadReceiverMismatch() throws
         MailboxStoragePayload mailboxStoragePayload = buildMailboxStoragePayload(senderKeys.getPublic(), receiverKeys.getPublic());
         ProtectedStorageEntry protectedStorageEntry = buildProtectedMailboxStorageEntry(mailboxStoragePayload, senderKeys, senderKeys.getPublic(), 1);
 
-        // should be assertFalse
-        Assert.assertTrue(protectedStorageEntry.isValidForAddOperation());
+        Assert.assertFalse(protectedStorageEntry.isValidForAddOperation());
     }
 
     // TESTCASE: validForAddOperation() should fail if the signature isn't valid