Fix DoDisconnect to signal connection termination

DoDisconnect was returning WS_SUCCESS after receiving
SSH_MSG_DISCONNECT, allowing the session to continue
processing packets. Per RFC 4253 §11.1, no further data
should be accepted after a disconnect message. Add new
WS_DISCONNECT error code and return it from DoDisconnect
so callers tear down the connection immediately.

F-605

Author: LinuxJedi

src/internal.c

@@ -491,6 +491,9 @@ const char* GetErrorString(int err)
         case WS_KDF_E:
             return "KDF error";
 
+        case WS_DISCONNECT:
+            return "peer sent disconnect";
+
         default:
             return "Unknown error code";
     }
@@ -6475,7 +6478,6 @@ static int DoDisconnect(WOLFSSH* ssh, byte* buf, word32 len, word32* idx)
     const char* reasonStr = NULL;
     word32 begin = *idx;
 
-    WOLFSSH_UNUSED(ssh);
     WOLFSSH_UNUSED(len);
     WOLFSSH_UNUSED(reasonStr);
 
@@ -6524,7 +6526,8 @@ static int DoDisconnect(WOLFSSH* ssh, byte* buf, word32 len, word32* idx)
 
     *idx = begin;
 
-    return WS_SUCCESS;
+    ssh->error = WS_DISCONNECT;
+    return WS_DISCONNECT;
 }
 
 

wolfssh/error.h

@@ -136,8 +136,9 @@ enum WS_ErrorCodes {
     WS_ED25519_E            = -1095, /* Ed25519 failure */
     WS_AUTH_PENDING         = -1096, /* User authentication still pending */
     WS_KDF_E                = -1097, /* KDF error*/
+    WS_DISCONNECT           = -1098, /* peer sent disconnect */
 
-    WS_LAST_E               = WS_KDF_E  /* Update this to indicate last error */
+    WS_LAST_E               = WS_DISCONNECT  /* Update this to indicate last error */
 };