Merge bitcoin/bitcoin#31040: test: Assert that when we add the max orphan amount that we cannot add anymore and that a random orphan gets dropped

5c299ecafe test: Assert that when we add the max orphan amount that we cannot add anymore and that a random orphan gets dropped (kevkevinpal)

Pull request description:

  After joining the bitcoin pr review club about https://github.com/bitcoin/bitcoin/pull/30793

  I learned about [`CVE-2012-3789`](https://github.com/bitcoin/bitcoin/blob/master/src/net_processing.cpp#L4693)

  So I was motivated to write a functional test that covers this part of the code,

  This test should add the max number of orphans to a nodes orphanage and then attempt to add another, then asserts that the number of orphans is still at the max amount

ACKs for top commit:
  achow101:
    ACK 5c299ecafe
  rkrux:
    ACK 5c299ecafe
  instagibbs:
    ACK 5c299ecafe
  tdb3:
    ACK 5c299ecafe

Tree-SHA512: 687bba337978e0945e94af71632998221e5565a5d83cf5a59ecf2ee52c7262d8ff907b94dceea3b80bed441dd19b24790b2904e88e1da14d30827c5469fcb4d3

test/functional/p2p_orphan_handling.py

@@ -5,6 +5,7 @@
 
 import time
 
+from test_framework.mempool_util import tx_in_orphanage
 from test_framework.messages import (
     CInv,
     CTxInWitness,
@@ -41,6 +42,8 @@ from test_framework.wallet import (
 # for one peer and y seconds for another, use specific values instead.
 TXREQUEST_TIME_SKIP = NONPREF_PEER_TX_DELAY + TXID_RELAY_DELAY + OVERLOADED_PEER_TX_DELAY + 1
 
+DEFAULT_MAX_ORPHAN_TRANSACTIONS = 100
+
 def cleanup(func):
     # Time to fastfoward (using setmocktime) in between subtests to ensure they do not interfere with
     # one another, in seconds. Equal to 12 hours, which is enough to expire anything that may exist
@@ -566,6 +569,47 @@ class OrphanHandlingTest(BitcoinTestFramework):
         assert tx_child["txid"] in node_mempool
         assert_equal(node.getmempoolentry(tx_child["txid"])["wtxid"], tx_child["wtxid"])
 
+    @cleanup
+    def test_max_orphan_amount(self):
+        self.log.info("Check that we never exceed our storage limits for orphans")
+
+        node = self.nodes[0]
+        self.generate(self.wallet, 1)
+        peer_1 = node.add_p2p_connection(P2PInterface())
+
+        self.log.info("Check that orphanage is empty on start of test")
+        assert len(node.getorphantxs()) == 0
+
+        self.log.info("Filling up orphanage with " + str(DEFAULT_MAX_ORPHAN_TRANSACTIONS) + "(DEFAULT_MAX_ORPHAN_TRANSACTIONS) orphans")
+        orphans = []
+        parent_orphans = []
+        for _ in range(DEFAULT_MAX_ORPHAN_TRANSACTIONS):
+            tx_parent_1 = self.wallet.create_self_transfer()
+            tx_child_1 = self.wallet.create_self_transfer(utxo_to_spend=tx_parent_1["new_utxo"])
+            parent_orphans.append(tx_parent_1["tx"])
+            orphans.append(tx_child_1["tx"])
+            peer_1.send_message(msg_tx(tx_child_1["tx"]))
+
+        peer_1.sync_with_ping()
+        orphanage = node.getorphantxs()
+        assert_equal(len(orphanage), DEFAULT_MAX_ORPHAN_TRANSACTIONS)
+
+        for orphan in orphans:
+            assert tx_in_orphanage(node, orphan)
+
+        self.log.info("Check that we do not add more than the max orphan amount")
+        tx_parent_1 = self.wallet.create_self_transfer()
+        tx_child_1 = self.wallet.create_self_transfer(utxo_to_spend=tx_parent_1["new_utxo"])
+        peer_1.send_and_ping(msg_tx(tx_child_1["tx"]))
+        parent_orphans.append(tx_parent_1["tx"])
+        orphanage = node.getorphantxs()
+        assert_equal(len(orphanage), DEFAULT_MAX_ORPHAN_TRANSACTIONS)
+
+        self.log.info("Clearing the orphanage")
+        for index, parent_orphan in enumerate(parent_orphans):
+            peer_1.send_and_ping(msg_tx(parent_orphan))
+        assert_equal(len(node.getorphantxs()),0)
+
 
     def run_test(self):
         self.nodes[0].setmocktime(int(time.time()))
@@ -582,6 +626,7 @@ class OrphanHandlingTest(BitcoinTestFramework):
         self.test_same_txid_orphan()
         self.test_same_txid_orphan_of_orphan()
         self.test_orphan_txid_inv()
+        self.test_max_orphan_amount()
 
 
 if __name__ == '__main__':

test/functional/rpc_getorphantxs.py

@@ -125,6 +125,5 @@ class GetOrphanTxsTest(BitcoinTestFramework):
             self.log.info("Check the transaction hex of orphan")
             assert_equal(orphan["hex"], tx["hex"])
 
-
 if __name__ == '__main__':
     GetOrphanTxsTest(__file__).main()