Fix overflow for permanent peer address TTL

Author: alienx5499

src/peer/address_repository/inmem_address_repository.cpp

@@ -67,6 +67,14 @@ namespace libp2p::peer {
   Clock::time_point InmemAddressRepository::calculateExpirationTime(
       const Milliseconds &ttl) const {
     static const auto max_time = Clock::time_point::max();
+    // permanent TTLs use milliseconds::max() as a sentinel
+    // doing arithmetic with that value (e.g. now + ttl or max_time - ttl)
+    // can overflow chrono durations and cause undefined behaviour
+    // instead of touching the sentinel in time math, map it directly to
+    // time_point::max() to mean "never expires"
+    if (ttl == ttl::kPermanent) {
+      return max_time;
+    }
     const auto now = Clock::now();
     if (now >= max_time - ttl) {
       return max_time;

test/libp2p/peer/address_repository/inmem_address_repository_test.cpp

@@ -186,3 +186,41 @@ TEST_F(InmemAddressRepository_Test, GetPeers) {
   auto s = db->getPeers();
   EXPECT_EQ(s.size(), 2);
 }
+
+/**
+ * @given address repository
+ * @when addAddresses/upsertAddresses with ttl::kPermanent
+ * @then addresses are stored and not evicted by collectGarbage
+ */
+TEST_F(InmemAddressRepository_Test, PermanentTtlNoOverflow) {
+  ASSERT_OUTCOME_SUCCESS(
+      db->addAddresses(p1, std::vector<Multiaddress>{ma1, ma2}, ttl::kPermanent));
+  ASSERT_OUTCOME_SUCCESS(
+      db->upsertAddresses(p2, std::vector<Multiaddress>{ma3}, ttl::kPermanent));
+
+  ASSERT_OUTCOME_SUCCESS(v1, db->getAddresses(p1));
+  ASSERT_OUTCOME_SUCCESS(v2, db->getAddresses(p2));
+  EXPECT_EQ(v1.size(), 2);
+  EXPECT_EQ(v2.size(), 1);
+
+  collectGarbage();
+  ASSERT_OUTCOME_SUCCESS(a1, db->getAddresses(p1));
+  ASSERT_OUTCOME_SUCCESS(a2, db->getAddresses(p2));
+  EXPECT_EQ(a1.size(), 2);
+  EXPECT_EQ(a2.size(), 1);
+  EXPECT_FALSE(a1.empty());
+  EXPECT_FALSE(a2.empty());
+}
+
+TEST_F(InmemAddressRepository_Test, LargeTtlClampedToMax) {
+  using namespace std::chrono;
+  auto large_ttl = milliseconds::max() - milliseconds(1);
+
+  ASSERT_OUTCOME_SUCCESS(
+      db->addAddresses(p1, std::vector<Multiaddress>{ma1}, large_ttl));
+
+  collectGarbage();
+
+  ASSERT_OUTCOME_SUCCESS(v, db->getAddresses(p1));
+  EXPECT_EQ(v.size(), 1);
+}