Disallow CASE establishment attempts over existing secure sessions.

Per spec, CASE establishment needs to happen via unauthenticated messages. We should ignore Sigma1 received over a CASE or PASE session.
project-chip · Feb 27, 2023 · 689e525 · 689e525
1 parent af511d7
commit 689e525
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Showing 2 changed files with 10 additions and 1 deletion.
diff --git a/src/protocols/secure_channel/CASEServer.cpp b/src/protocols/secure_channel/CASEServer.cpp
@@ -73,7 +73,14 @@ CHIP_ERROR CASEServer::OnUnsolicitedMessageReceived(const PayloadHeader & payloa
 CHIP_ERROR CASEServer::OnMessageReceived(Messaging::ExchangeContext * ec, const PayloadHeader & payloadHeader,
                                          System::PacketBufferHandle && payload)
 {
-    ChipLogProgress(Inet, "CASE Server received Sigma1 message. Starting handshake. EC %p", ec);
+    if (!ec->GetSessionHandle()->IsUnauthenticatedSesssion())
+    {
+        ChipLogError(Inet, "CASE Server received Sigma1 message %s EC %p", "over encrypted session. Ignoring.", ec);
+        return CHIP_ERROR_INCORRECT_STATE;
+    }
+
+    ChipLogProgress(Inet, "CASE Server received Sigma1 message %s EC %p", ". Starting handshake.", ec);
+
     CHIP_ERROR err = InitCASEHandshake(ec);
     SuccessOrExit(err);
 

diff --git a/src/transport/Session.h b/src/transport/Session.h
@@ -222,6 +222,8 @@ class Session
 
     bool IsSecureSession() const { return GetSessionType() == SessionType::kSecure; }
 
+    bool IsUnauthenticatedSession() const { return GetSessionType() == SessionType::kUnauthenticated; }
+
     void DispatchSessionEvent(SessionDelegate::Event event)
     {
         // Holders might remove themselves when notified.