Fix CASEServer cleanup to not nuke unrelated CASE handshakes.

src/protocols/secure_channel/CASEServer.cpp

@@ -86,11 +86,8 @@ CHIP_ERROR CASEServer::OnMessageReceived(Messaging::ExchangeContext * ec, const
     SuccessOrExit(err);
 
 exit:
-    if (err != CHIP_NO_ERROR)
-    {
-        PrepareForSessionEstablishment();
-    }
-
+    // CASESession::OnMessageReceived guarantees that it will call
+    // OnSessionEstablishmentError if it returns error, so nothing else to do here.
     return err;
 }
 
@@ -157,16 +154,7 @@ void CASEServer::OnSessionEstablishmentError(CHIP_ERROR err)
 {
     ChipLogError(Inet, "CASE Session establishment failed: %" CHIP_ERROR_FORMAT, err.Format());
 
-    //
-    // We're not allowed to call methods that will eventually result in calling SessionManager::AllocateSecureSession
-    // from a SessionDelegate::OnSessionReleased callback. Schedule the preparation as an async work item.
-    //
-    mSessionManager->SystemLayer()->ScheduleWork(
-        [](auto * systemLayer, auto * appState) -> void {
-            CASEServer * _this = static_cast<CASEServer *>(appState);
-            _this->PrepareForSessionEstablishment();
-        },
-        this);
+    PrepareForSessionEstablishment();
 }
 
 void CASEServer::OnSessionEstablished(const SessionHandle & session)

src/protocols/secure_channel/CASESession.cpp

@@ -134,9 +134,9 @@ CASESession::~CASESession()
 
 void CASESession::OnSessionReleased()
 {
+    // Call into our super-class before we clear our state.
+    PairingSession::OnSessionReleased();
     Clear();
-    // Do this last in case the delegate frees us.
-    NotifySessionEstablishmentError(CHIP_ERROR_CONNECTION_ABORTED);
 }
 
 void CASESession::Clear()

src/protocols/secure_channel/PASESession.cpp

@@ -75,9 +75,9 @@ PASESession::~PASESession()
 
 void PASESession::OnSessionReleased()
 {
+    // Call into our super-class before we clear our state.
+    PairingSession::OnSessionReleased();
     Clear();
-    // Do this last in case the delegate frees us.
-    NotifySessionEstablishmentError(CHIP_ERROR_CONNECTION_ABORTED);
 }
 
 void PASESession::Finish()

src/protocols/secure_channel/PairingSession.cpp

@@ -182,4 +182,29 @@ void PairingSession::NotifySessionEstablishmentError(CHIP_ERROR error)
     delegate->OnSessionEstablishmentError(error);
 }
 
+void PairingSession::OnSessionReleased()
+{
+    if (mRole == CryptoContext::SessionRole::kInitiator)
+    {
+        NotifySessionEstablishmentError(CHIP_ERROR_CONNECTION_ABORTED);
+        return;
+    }
+
+    // Send the error notification async, because our delegate is likely to want
+    // to create a new session to listen for new connection attempts, and doing
+    // that under an OnSessionReleased notification is not safe.
+    if (!mSessionManager)
+    {
+        return;
+    }
+
+    mSessionManager->SystemLayer()->ScheduleWork(
+        [](auto * systemLayer, auto * appState) -> void {
+            ChipLogError(Inet, "ASYNC CASE Session establishment failed");
+            auto * _this = static_cast<PairingSession *>(appState);
+            _this->NotifySessionEstablishmentError(CHIP_ERROR_CONNECTION_ABORTED);
+        },
+        this);
+}
+
 } // namespace chip

src/protocols/secure_channel/PairingSession.h

@@ -51,6 +51,7 @@ class DLL_EXPORT PairingSession : public SessionDelegate
 
     // Implement SessionDelegate
     NewSessionHandlingPolicy GetNewSessionHandlingPolicy() override { return NewSessionHandlingPolicy::kStayAtOldSession; }
+    void OnSessionReleased() override;
 
     Optional<uint16_t> GetLocalSessionId() const
     {

src/protocols/secure_channel/tests/TestPASESession.cpp

@@ -324,6 +324,12 @@ void SecurePairingHandshakeTestCommon(nlTestSuite * inSuite, void * inContext, S
     NL_TEST_ASSERT(inSuite, session.HasValue());
     session.Value()->AsSecureSession()->MarkForEviction();
 
+    // Evicting a session async notifies the PASESession's delegate.  Normally
+    // that notification is what would delete the PASESession, but in our case
+    // that will happen as soon as things come off the stack.  So make sure to
+    // process the async bits before that happens.
+    ctx.DrainAndServiceIO();
+
     // And check that this did not result in any new notifications.
     NL_TEST_ASSERT(inSuite, delegateAccessory.mNumPairingErrors == 0);
     NL_TEST_ASSERT(inSuite, delegateAccessory.mNumPairingComplete == 1);