src: Fix memory leaks in generate_test_instance() by returning values instead of pointers

Problem:

The current `generate_test_instance()` function returns `std::list<T*>`,
which creates memory management issues:

- Inconsistent lifecycle management of test instances
- Callers don't always properly clean up allocated memory
- Results in ASan memory leak reports in unit tests and ceph-dencoder

Solution:

Change `generate_test_instance()` to return `std::list<T>` instead of `std::list<T*>`:

Core Changes:

- Modified all classes with `generate_test_instance()` to return `std::list<T>`
- Use `emplace_back()` without parameters** to avoid copy/move
  constructors for classes that don't define them
- Updated ceph-dencoder to handle the new return type

ceph-dencoder Adaptations:

Since `m_list` now holds `T` objects instead of `T*`, and we can't
assume `T` is copyable/moveable:

- Keep `m_object` as a pointer for flexibility
- Handle two scenarios:
  1. `m_object` points to an element in `m_list`
  2. `m_object` points to a decoded instance (requires manual cleanup)
- Introduce `make_ptr()` as a factory function to create a smart pointer
  to conditionally free the managed pointer.

Additional Cleanup:

- Simplify DencoderBase constructor from template to plain
  function (extra parameters were never used in derived classes)

With this change, object lifecycles are now managed by value semantics
instead of raw pointers, eliminating memory leaks.

Signed-off-by: Kefu Chai <[email protected]>

Author: tchaikov

src/auth/Auth.h

@@ -74,8 +74,10 @@ struct EntityAuth {
     encode_json("caps", caps, f);
     f->dump_object("pending_key", pending_key);
   }
-  static void generate_test_instances(std::list<EntityAuth*>& ls) {
-    ls.push_back(new EntityAuth);
+  static std::list<EntityAuth> generate_test_instances() {
+    std::list<EntityAuth> ls;
+    ls.push_back(EntityAuth{});
+    return ls;
   }
 };
 WRITE_CLASS_ENCODER(EntityAuth)
@@ -118,13 +120,15 @@ struct AuthCapsInfo {
     encode_json("caps", caps, f);
     f->dump_unsigned("caps_len", caps.length());
   }
-  static void generate_test_instances(std::list<AuthCapsInfo*>& ls) {
-    ls.push_back(new AuthCapsInfo);
-    ls.push_back(new AuthCapsInfo);
-    ls.back()->allow_all = true;
-    ls.push_back(new AuthCapsInfo);
-    ls.back()->caps.append("foo");
-    ls.back()->caps.append("bar");
+  static std::list<AuthCapsInfo> generate_test_instances() {
+    std::list<AuthCapsInfo> ls;
+    ls.push_back(AuthCapsInfo{});
+    ls.push_back(AuthCapsInfo{});
+    ls.back().allow_all = true;
+    ls.push_back(AuthCapsInfo{});
+    ls.back().caps.append("foo");
+    ls.back().caps.append("bar");
+    return ls;
   }
 };
 WRITE_CLASS_ENCODER(AuthCapsInfo)
@@ -184,15 +188,17 @@ struct AuthTicket {
     f->dump_object("caps", caps);
     f->dump_unsigned("flags", flags);
   }
-  static void generate_test_instances(std::list<AuthTicket*>& ls) {
-    ls.push_back(new AuthTicket);
-    ls.push_back(new AuthTicket);
-    ls.back()->name.set_id("client.123");
-    ls.back()->global_id = 123;
-    ls.back()->init_timestamps(utime_t(123, 456), 7);
-    ls.back()->caps.caps.append("foo");
-    ls.back()->caps.caps.append("bar");
-    ls.back()->flags = 0x12345678;
+  static std::list<AuthTicket> generate_test_instances() {
+    std::list<AuthTicket> ls;
+    ls.push_back(AuthTicket{});
+    ls.push_back(AuthTicket{});
+    ls.back().name.set_id("client.123");
+    ls.back().global_id = 123;
+    ls.back().init_timestamps(utime_t(123, 456), 7);
+    ls.back().caps.caps.append("foo");
+    ls.back().caps.caps.append("bar");
+    ls.back().flags = 0x12345678;
+    return ls;
   }
 };
 WRITE_CLASS_ENCODER(AuthTicket)
@@ -282,11 +288,13 @@ struct ExpiringCryptoKey {
     f->dump_object("key", key);
     f->dump_stream("expiration") << expiration;
   }
-  static void generate_test_instances(std::list<ExpiringCryptoKey*>& ls) {
-    ls.push_back(new ExpiringCryptoKey);
-    ls.push_back(new ExpiringCryptoKey);
-    ls.back()->key.set_secret(
+  static std::list<ExpiringCryptoKey> generate_test_instances() {
+    std::list<ExpiringCryptoKey> ls;
+    ls.push_back(ExpiringCryptoKey{});
+    ls.push_back(ExpiringCryptoKey{});
+    ls.back().key.set_secret(
       CEPH_CRYPTO_AES, bufferptr("1234567890123456", 16), utime_t(123, 456));
+    return ls;
   }
 };
 WRITE_CLASS_ENCODER(ExpiringCryptoKey)
@@ -355,11 +363,13 @@ struct RotatingSecrets {
   void dump(ceph::Formatter *f) const {
     encode_json("secrets", secrets, f);
   }
-  static void generate_test_instances(std::list<RotatingSecrets*>& ls) {
-    ls.push_back(new RotatingSecrets);
-    ls.push_back(new RotatingSecrets);
-    auto eck = new ExpiringCryptoKey;
-    ls.back()->add(*eck);
+  static std::list<RotatingSecrets> generate_test_instances() {
+    std::list<RotatingSecrets> ls;
+    ls.push_back(RotatingSecrets{});
+    ls.push_back(RotatingSecrets{});
+    ExpiringCryptoKey eck{};
+    ls.back().add(eck);
+    return ls;
   }
 };
 WRITE_CLASS_ENCODER(RotatingSecrets)

src/auth/Crypto.cc

@@ -519,14 +519,16 @@ void CryptoKey::dump(Formatter *f) const
   f->dump_int("secret.length", secret.length());
 }
 
-void CryptoKey::generate_test_instances(std::list<CryptoKey*>& ls)
+std::list<CryptoKey> CryptoKey::generate_test_instances()
 {
-  ls.push_back(new CryptoKey);
-  ls.push_back(new CryptoKey);
-  ls.back()->type = CEPH_CRYPTO_AES;
-  ls.back()->set_secret(
+  std::list<CryptoKey> ls;
+  ls.emplace_back();
+  ls.emplace_back();
+  ls.back().type = CEPH_CRYPTO_AES;
+  ls.back().set_secret(
     CEPH_CRYPTO_AES, bufferptr("1234567890123456", 16), utime_t(123, 456));
-  ls.back()->created = utime_t(123, 456);
+  ls.back().created = utime_t(123, 456);
+  return ls;
 }
 
 int CryptoKey::set_secret(int type, const bufferptr& s, utime_t c)

src/auth/Crypto.h

@@ -112,7 +112,7 @@ class CryptoKey {
   void encode(ceph::buffer::list& bl) const;
   void decode(ceph::buffer::list::const_iterator& bl);
   void dump(ceph::Formatter *f) const;
-  static void generate_test_instances(std::list<CryptoKey*>& ls);
+  static std::list<CryptoKey> generate_test_instances();
 
   void clear() {
     *this = CryptoKey();

src/auth/cephx/CephxKeyServer.cc

@@ -263,9 +263,11 @@ void KeyServer::dump(Formatter *f) const
   f->dump_object("data", data);
 }
 
-void KeyServer::generate_test_instances(std::list<KeyServer*>& ls)
+std::list<KeyServer> KeyServer::generate_test_instances()
 {
-  ls.push_back(new KeyServer(nullptr, nullptr));
+  std::list<KeyServer> ls;
+  ls.emplace_back(nullptr, nullptr);
+  return ls;
 }
 
 bool KeyServer::generate_secret(CryptoKey& secret)

src/auth/cephx/CephxKeyServer.h

@@ -78,10 +78,12 @@ struct KeyServerData {
     encode_json("secrets", secrets, f);
     encode_json("rotating_secrets", rotating_secrets, f);
   }
-  static void generate_test_instances(std::list<KeyServerData*>& ls) {
-    ls.push_back(new KeyServerData);
-    ls.push_back(new KeyServerData);
-    ls.back()->version = 1;
+  static std::list<KeyServerData> generate_test_instances() {
+    std::list<KeyServerData> ls;
+    ls.push_back(KeyServerData{});
+    ls.push_back(KeyServerData{});
+    ls.back().version = 1;
+    return ls;
   }
   bool contains(const EntityName& name) const {
     return (secrets.find(name) != secrets.end());
@@ -176,13 +178,15 @@ struct KeyServerData {
       f->dump_object("name", name);
       f->dump_object("auth", auth);
     }
-    static void generate_test_instances(std::list<Incremental*>& ls) {
-      ls.push_back(new Incremental);
-      ls.back()->op = AUTH_INC_DEL;
-      ls.push_back(new Incremental);
-      ls.back()->op = AUTH_INC_ADD;
-      ls.push_back(new Incremental);
-      ls.back()->op = AUTH_INC_SET_ROTATING;
+    static std::list<Incremental> generate_test_instances() {
+      std::list<Incremental> ls;
+      ls.push_back(Incremental{});
+      ls.back().op = AUTH_INC_DEL;
+      ls.push_back(Incremental{});
+      ls.back().op = AUTH_INC_ADD;
+      ls.push_back(Incremental{});
+      ls.back().op = AUTH_INC_SET_ROTATING;
+      return ls;
     }
   };
 
@@ -274,7 +278,7 @@ class KeyServer : public KeyStore {
     decode(data, bl);
   }
   void dump(ceph::Formatter *f) const;
-  static void generate_test_instances(std::list<KeyServer*>& ls);
+  static std::list<KeyServer> generate_test_instances();
   bool contains(const EntityName& name) const;
   int encode_secrets(ceph::Formatter *f, std::stringstream *ds) const;
   void encode_formatted(std::string label, ceph::Formatter *f, ceph::buffer::list &bl);