Release PSA crypto state in uninitNetSystem(), not per socket (fixes #612)

docs/usage.md

@@ -4,7 +4,7 @@ The [*ws*](https://github.com/machinezone/IXWebSocket/tree/master/ws) folder cou
 
 ## Windows note
 
-To use the network system on Windows, you need to initialize it once with *WSAStartup()* and clean it up with *WSACleanup()*. We have helpers for that which you can use, see below. This init would typically take place in your main function.
+To use the network system on Windows, you need to initialize it once with *WSAStartup()* and clean it up with *WSACleanup()*. We have helpers for that which you can use, see below. This init would typically take place in your main function. On every platform, *ix::uninitNetSystem()* also releases process-global TLS state (mbedTLS PSA crypto, with mbedTLS >= 3.6), so call it only after all sockets are closed.
 
 ```cpp
 #include <ixwebsocket/IXNetSystem.h>

ixwebsocket/IXNetSystem.cpp

@@ -7,6 +7,12 @@
 #include "IXNetSystem.h"
 #include <cstdint>
 #include <cstdio>
+#ifdef IXWEBSOCKET_USE_MBED_TLS
+#include <mbedtls/version.h>
+#if MBEDTLS_VERSION_MAJOR >= 4 || (MBEDTLS_VERSION_MAJOR == 3 && MBEDTLS_VERSION_MINOR >= 6)
+#include <psa/crypto.h>
+#endif
+#endif
 #ifdef _WIN32
 #ifndef EAFNOSUPPORT
   #define EAFNOSUPPORT 102
@@ -38,6 +44,9 @@ namespace ix
 
     bool uninitNetSystem()
     {
+#if defined(IXWEBSOCKET_USE_MBED_TLS) && (MBEDTLS_VERSION_MAJOR >= 4 || (MBEDTLS_VERSION_MAJOR == 3 && MBEDTLS_VERSION_MINOR >= 6))
+        mbedtls_psa_crypto_free();
+#endif
 #ifdef _WIN32
         int err = WSACleanup();
         return err == 0;

ixwebsocket/IXNetSystem.h

@@ -88,6 +88,7 @@ namespace ix
 #endif
 
     bool initNetSystem();
+    // Also releases process-global TLS (PSA) state; call only after all sockets are closed.
     bool uninitNetSystem();
 
     int poll(struct pollfd* fds, nfds_t nfds, int timeout, void** event);

ixwebsocket/IXSocketMbedTLS.cpp

@@ -40,15 +40,19 @@ namespace ix
     {
         std::lock_guard<std::mutex> lock(_mutex);
 
-        mbedtls_ssl_init(&_ssl);
-        mbedtls_ssl_config_init(&_conf);
+        if (!_mbedtlsInitialized)
+        {
+            _mbedtlsInitialized = true;
+            mbedtls_ssl_init(&_ssl);
+            mbedtls_ssl_config_init(&_conf);
 #if MBEDTLS_VERSION_MAJOR < 4
-        mbedtls_ctr_drbg_init(&_ctr_drbg);
-        mbedtls_entropy_init(&_entropy);
+            mbedtls_ctr_drbg_init(&_ctr_drbg);
+            mbedtls_entropy_init(&_entropy);
 #endif
-        mbedtls_x509_crt_init(&_cacert);
-        mbedtls_x509_crt_init(&_cert);
-        mbedtls_pk_init(&_pkey);
+            mbedtls_x509_crt_init(&_cacert);
+            mbedtls_x509_crt_init(&_cert);
+            mbedtls_pk_init(&_pkey);
+        }
         // Initialize the PSA Crypto API for mbedTLS 3.6+ and all 4.x releases.
         // See: https://github.com/Mbed-TLS/mbedtls/blob/development/docs/use-psa-crypto.md
 #if MBEDTLS_VERSION_MAJOR >= 4 || (MBEDTLS_VERSION_MAJOR == 3 && MBEDTLS_VERSION_MINOR >= 6)
@@ -111,6 +115,15 @@ namespace ix
         initMBedTLS();
         std::lock_guard<std::mutex> lock(_mutex);
 
+#if MBEDTLS_VERSION_MAJOR >= 4 || (MBEDTLS_VERSION_MAJOR == 3 && MBEDTLS_VERSION_MINOR >= 6)
+        psa_status_t status = psa_crypto_init();
+        if (status != PSA_SUCCESS)
+        {
+            errMsg = "PSA crypto init failed: " + std::to_string((int) status);
+            return false;
+        }
+#endif
+
 #if MBEDTLS_VERSION_MAJOR < 4
         const char* pers = "IXSocketMbedTLS";
         if (mbedtls_ctr_drbg_seed(&_ctr_drbg,
@@ -328,9 +341,9 @@ namespace ix
         mbedtls_x509_crt_free(&_cacert);
         mbedtls_x509_crt_free(&_cert);
         mbedtls_pk_free(&_pkey);
-#if MBEDTLS_VERSION_MAJOR >= 4 || (MBEDTLS_VERSION_MAJOR == 3 && MBEDTLS_VERSION_MINOR >= 6)
-        mbedtls_psa_crypto_free();
-#endif
+        _mbedtlsInitialized = false;
+        // PSA crypto state is process-global; it is released in ix::uninitNetSystem(),
+        // not per socket.
 
         Socket::close();
     }

ixwebsocket/IXSocketMbedTLS.h

@@ -54,6 +54,7 @@ namespace ix
 
         std::mutex _mutex;
         SocketTLSOptions _tlsOptions;
+        bool _mbedtlsInitialized = false;
 
         bool init(const std::string& host, bool isClient, std::string& errMsg);
         void initMBedTLS();

test/CMakeLists.txt

@@ -47,6 +47,12 @@ if (USE_ZLIB)
   )
 endif()
 
+if (USE_TLS AND USE_MBED_TLS)
+  list(APPEND TEST_TARGET_NAMES
+    IXSocketMbedTLSPSATest
+  )
+endif()
+
 # Ping test fails intermittently, disabling them for now
 # IXWebSocketPingTest.cpp
 # IXWebSocketPingTimeoutTest.cpp

test/IXSocketMbedTLSPSATest.cpp

@@ -0,0 +1,93 @@
+/*
+ *  IXSocketMbedTLSPSATest.cpp
+ *
+ *  PSA crypto state is process-global: closing one SocketMbedTLS must not
+ *  tear it down under other live sockets.
+ */
+
+#ifdef IXWEBSOCKET_USE_MBED_TLS
+
+#include <catch_amalgamated.hpp>
+#include <ixwebsocket/IXNetSystem.h>
+#include <mbedtls/version.h>
+
+using namespace ix;
+
+#if MBEDTLS_VERSION_MAJOR >= 4 || (MBEDTLS_VERSION_MAJOR == 3 && MBEDTLS_VERSION_MINOR >= 6)
+
+#include <iostream>
+#include <ixwebsocket/IXSocketMbedTLS.h>
+#include <psa/crypto.h>
+
+namespace
+{
+    // Hashing works without PSA init, so probe the RNG and a key slot instead.
+    bool psaStateWorks()
+    {
+        uint8_t bytes[16];
+        psa_status_t status = psa_generate_random(bytes, sizeof(bytes));
+        if (status != PSA_SUCCESS)
+        {
+            std::cerr << "psa_generate_random failed: " << (int) status << std::endl;
+            return false;
+        }
+
+        psa_key_attributes_t attributes = PSA_KEY_ATTRIBUTES_INIT;
+        psa_set_key_type(&attributes, PSA_KEY_TYPE_HMAC);
+        psa_set_key_bits(&attributes, 128);
+        psa_set_key_usage_flags(&attributes, PSA_KEY_USAGE_SIGN_MESSAGE);
+        psa_set_key_algorithm(&attributes, PSA_ALG_HMAC(PSA_ALG_SHA_256));
+
+        psa_key_id_t key = 0;
+        status = psa_import_key(&attributes, bytes, sizeof(bytes), &key);
+        psa_reset_key_attributes(&attributes);
+        if (status != PSA_SUCCESS)
+        {
+            std::cerr << "psa_import_key failed: " << (int) status << std::endl;
+            return false;
+        }
+
+        return psa_destroy_key(key) == PSA_SUCCESS;
+    }
+} // namespace
+
+TEST_CASE("SocketMbedTLS close does not tear down process-global PSA state", "[socket_mbedtls]")
+{
+    SocketMbedTLS a(SocketTLSOptions{});
+    REQUIRE(psaStateWorks());
+
+    {
+        SocketMbedTLS b(SocketTLSOptions{});
+        b.close();
+    }
+    REQUIRE(psaStateWorks());
+
+    a.close();
+
+    SocketMbedTLS c(SocketTLSOptions{});
+    REQUIRE(psaStateWorks());
+}
+
+TEST_CASE("uninitNetSystem releases PSA state and allows re-init", "[socket_mbedtls]")
+{
+    REQUIRE(initNetSystem());
+    {
+        SocketMbedTLS a(SocketTLSOptions{});
+        a.close();
+    }
+    REQUIRE(uninitNetSystem());
+
+    REQUIRE(psa_crypto_init() == PSA_SUCCESS);
+    REQUIRE(psaStateWorks());
+}
+
+#else // mbedTLS < 3.6
+
+TEST_CASE("SocketMbedTLS PSA lifetime (not applicable below mbedTLS 3.6)", "[socket_mbedtls]")
+{
+    SUCCEED("mbedTLS < 3.6 has no PSA state to release");
+}
+
+#endif // mbedTLS >= 3.6
+
+#endif // IXWEBSOCKET_USE_MBED_TLS