Memory leak when using Activities and Secure Sockets

[StephanieSJ]

I am getting a memory leak when using an activity in conjunction with secure sockets.
Example code:

#include <string>
#include <iostream>
#include <csignal>
#include <cstdlib>
#include <chrono>
#include <thread>

#include "Poco/Activity.h"
#include "Poco/Net/SecureStreamSocket.h"

class TestingClient {
 private:
  Poco::Activity<TestingClient> test_activity;

  void run() {
    Poco::Net::SecureStreamSocket client_socket(
        Poco::Net::SocketAddress("127.0.0.1", 27560),
        new Poco::Net::Context(
            Poco::Net::Context::TLSV1_2_CLIENT_USE, "../certs/client.key",
            "../certs/client.crt", "../certs/ca-crt.pem",
            Poco::Net::Context::VERIFY_STRICT, 9, false,
            "EECDH+AESGCM:EDH+AESGCM:AES256+EECDH:AES256+EDH"));
    client_socket.close();
  }

 public:
  TestingClient() : test_activity(this, &TestingClient::run) {}

  void start() { test_activity.start(); }

  void stop() {
    test_activity.stop();
    test_activity.wait();
  }
};

sig_atomic_t stopFlag = 0;
void signal_handler(int signum) {
  switch (signum) {
    case (SIGINT):
    case (SIGTERM): {
      stopFlag = 1;
      break;
    }
  }
}

int main() {
  signal(SIGINT, &signal_handler);
  signal(SIGTERM, &signal_handler);

  std::cout << "CREATING CLIENT" << std::endl;
  TestingClient test_client;
  std::cout << "STARTING CLIENT" << std::endl;
  test_client.start();
  std::cout << "IDLING" << std::endl;
  while (stopFlag == 0) {
    std::this_thread::sleep_for(std::chrono::milliseconds(100));
  }
  test_client.stop();
  return 0;
}

Valgrind output:

==5459== HEAP SUMMARY:
==5459==     in use at exit: 4,164 bytes in 20 blocks
==5459==   total heap usage: 5,519 allocs, 5,499 frees, 440,373 bytes allocated
==5459==
==5459== 12 bytes in 1 blocks are definitely lost in loss record 1 of 20
==5459==    at 0x4842839: malloc (in /usr/libexec/valgrind/vgpreload_memcheck-amd64-linux.so)
==5459==    by 0x52366CD: CRYPTO_zalloc (in /usr/lib/x86_64-linux-gnu/libcrypto.so.1.1)
==5459==    by 0x52336F5: ??? (in /usr/lib/x86_64-linux-gnu/libcrypto.so.1.1)
==5459==    by 0x520C89F: ERR_get_state (in /usr/lib/x86_64-linux-gnu/libcrypto.so.1.1)
==5459==    by 0x52104BC: ERR_clear_error (in /usr/lib/x86_64-linux-gnu/libcrypto.so.1.1)
==5459==    by 0x5232AE6: ??? (in /usr/lib/x86_64-linux-gnu/libcrypto.so.1.1)
==5459==    by 0x4BB04AF: __pthread_once_slow (pthread_once.c:116)
==5459==    by 0x527175C: CRYPTO_THREAD_run_once (in /usr/lib/x86_64-linux-gnu/libcrypto.so.1.1)
==5459==    by 0x523350A: OPENSSL_init_crypto (in /usr/lib/x86_64-linux-gnu/libcrypto.so.1.1)
==5459==    by 0x52328A3: ??? (in /usr/lib/x86_64-linux-gnu/libcrypto.so.1.1)
==5459==    by 0x4BB04AF: __pthread_once_slow (pthread_once.c:116)
==5459==    by 0x527175C: CRYPTO_THREAD_run_once (in /usr/lib/x86_64-linux-gnu/libcrypto.so.1.1)
==5459==
==5459== 584 bytes in 1 blocks are definitely lost in loss record 18 of 20
==5459==    at 0x4842839: malloc (in /usr/libexec/valgrind/vgpreload_memcheck-amd64-linux.so)
==5459==    by 0x52366CD: CRYPTO_zalloc (in /usr/lib/x86_64-linux-gnu/libcrypto.so.1.1)
==5459==    by 0x520C88D: ERR_get_state (in /usr/lib/x86_64-linux-gnu/libcrypto.so.1.1)
==5459==    by 0x52104BC: ERR_clear_error (in /usr/lib/x86_64-linux-gnu/libcrypto.so.1.1)
==5459==    by 0x5232AE6: ??? (in /usr/lib/x86_64-linux-gnu/libcrypto.so.1.1)
==5459==    by 0x4BB04AF: __pthread_once_slow (pthread_once.c:116)
==5459==    by 0x527175C: CRYPTO_THREAD_run_once (in /usr/lib/x86_64-linux-gnu/libcrypto.so.1.1)
==5459==    by 0x523350A: OPENSSL_init_crypto (in /usr/lib/x86_64-linux-gnu/libcrypto.so.1.1)
==5459==    by 0x52328A3: ??? (in /usr/lib/x86_64-linux-gnu/libcrypto.so.1.1)
==5459==    by 0x4BB04AF: __pthread_once_slow (pthread_once.c:116)
==5459==    by 0x527175C: CRYPTO_THREAD_run_once (in /usr/lib/x86_64-linux-gnu/libcrypto.so.1.1)
==5459==    by 0x5233475: OPENSSL_init_crypto (in /usr/lib/x86_64-linux-gnu/libcrypto.so.1.1)
==5459==
==5459== 1,784 (376 direct, 1,408 indirect) bytes in 1 blocks are definitely lost in loss record 19 of 20
==5459==    at 0x4842839: malloc (in /usr/libexec/valgrind/vgpreload_memcheck-amd64-linux.so)
==5459==    by 0x52366CD: CRYPTO_zalloc (in /usr/lib/x86_64-linux-gnu/libcrypto.so.1.1)
==5459==    by 0x5258E1A: ??? (in /usr/lib/x86_64-linux-gnu/libcrypto.so.1.1)
==5459==    by 0x52593BD: ??? (in /usr/lib/x86_64-linux-gnu/libcrypto.so.1.1)
==5459==    by 0x52599A1: RAND_DRBG_get0_public (in /usr/lib/x86_64-linux-gnu/libcrypto.so.1.1)
==5459==    by 0x52599D3: ??? (in /usr/lib/x86_64-linux-gnu/libcrypto.so.1.1)
==5459==    by 0x50A63FE: SSL_CTX_new (in /usr/lib/x86_64-linux-gnu/libssl.so.1.1)
==5459==    by 0x48943CC: Poco::Net::Context::createSSLContext() (in /usr/lib/x86_64-linux-gnu/libPocoNetSSL.so.62)
==5459==    by 0x48949FA: Poco::Net::Context::init(Poco::Net::Context::Params const&) (in /usr/lib/x86_64-linux-gnu/libPocoNetSSL.so.62)
==5459==    by 0x4894E1F: Poco::Net::Context::Context(Poco::Net::Context::Usage, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, Poco::Net::Context::VerificationMode, int, bool, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) (in /usr/lib/x86_64-linux-gnu/libPocoNetSSL.so.62)
==5459==    by 0x10CAF3: TestingClient::run() (in /home/sjacobs/code_testing/Cpp_testing/bin/poco_tests)
==5459==    by 0x10C6C6: Poco::Activity<TestingClient>::run() (in /home/sjacobs/code_testing/Cpp_testing/bin/poco_tests)
==5459==
==5459== 1,784 (376 direct, 1,408 indirect) bytes in 1 blocks are definitely lost in loss record 20 of 20
==5459==    at 0x4842839: malloc (in /usr/libexec/valgrind/vgpreload_memcheck-amd64-linux.so)
==5459==    by 0x52366CD: CRYPTO_zalloc (in /usr/lib/x86_64-linux-gnu/libcrypto.so.1.1)
==5459==    by 0x5258E1A: ??? (in /usr/lib/x86_64-linux-gnu/libcrypto.so.1.1)
==5459==    by 0x52593BD: ??? (in /usr/lib/x86_64-linux-gnu/libcrypto.so.1.1)
==5459==    by 0x5259A71: RAND_DRBG_get0_private (in /usr/lib/x86_64-linux-gnu/libcrypto.so.1.1)
==5459==    by 0x5259CD9: RAND_priv_bytes (in /usr/lib/x86_64-linux-gnu/libcrypto.so.1.1)
==5459==    by 0x50A6620: SSL_CTX_new (in /usr/lib/x86_64-linux-gnu/libssl.so.1.1)
==5459==    by 0x48943CC: Poco::Net::Context::createSSLContext() (in /usr/lib/x86_64-linux-gnu/libPocoNetSSL.so.62)
==5459==    by 0x48949FA: Poco::Net::Context::init(Poco::Net::Context::Params const&) (in /usr/lib/x86_64-linux-gnu/libPocoNetSSL.so.62)
==5459==    by 0x4894E1F: Poco::Net::Context::Context(Poco::Net::Context::Usage, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, Poco::Net::Context::VerificationMode, int, bool, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) (in /usr/lib/x86_64-linux-gnu/libPocoNetSSL.so.62)
==5459==    by 0x10CAF3: TestingClient::run() (in /home/sjacobs/code_testing/Cpp_testing/bin/poco_tests)
==5459==    by 0x10C6C6: Poco::Activity<TestingClient>::run() (in /home/sjacobs/code_testing/Cpp_testing/bin/poco_tests)
==5459==
==5459== LEAK SUMMARY:
==5459==    definitely lost: 1,348 bytes in 4 blocks
==5459==    indirectly lost: 2,816 bytes in 16 blocks
==5459==      possibly lost: 0 bytes in 0 blocks
==5459==    still reachable: 0 bytes in 0 blocks
==5459==         suppressed: 0 bytes in 0 blocks
==5459==
==5459== For lists of detected and suppressed errors, rerun with: -s
==5459== ERROR SUMMARY: 4 errors from 4 contexts (suppressed: 0 from 0)

The leak is not present when using a standard thread and joining the thread. And from testing and investigating it seems to be an issue where the default ThreadPool is not cleaning up properly since the leak is not present if I manually call the destructor of the default ThreadPool.

I am not sure if there is something I am doing wrong when handling SecureSockets but I didn't have this issue before switching over to Activities from just the standard c++ threads.

[StephanieSJ]

Found a fix which is to just call Poco::ThreadPool::defaultPool().stopAll() before closing the program.