Merge nucleic/lucid-river-toad-6efj into dev

spikes/WslcApiDump/InternalComProbe.cs

@@ -82,11 +82,35 @@ internal static class InternalComProbe
             Console.WriteLine($"  {name}  {{{clsid}}}");
             Console.WriteLine($"    ({source})");
 
-            var iunknown = typeof(object).GUID;   // IID_IUnknown
+            var hr = CoCreateInstance(in clsid, IntPtr.Zero, ClsctxAll, in IidIUnknown, out var unknown);
-            var hr = CoCreateInstance(in clsid, IntPtr.Zero, ClsctxAll, in iunknown, out var unknown);
             if (hr < 0)
             {
                 Console.WriteLine($"    activation failed: {Hresult(hr)}");
+                if ((uint)hr == ENoInterface)
+                    // Every COM object implements IUnknown, so this combination is impossible
+                    // unless the IID being passed is not IID_IUnknown. Say so loudly: the first
+                    // version of this probe did exactly that and reported a confident false
+                    // negative that read like a real finding about WSL.
+                    Console.WriteLine("    !! E_NOINTERFACE on an IUnknown activation is IMPOSSIBLE — "
+                        + "every COM object implements IUnknown. This probe is passing a wrong IID; "
+                        + "treat the whole run as void and fix it, do NOT record a finding.");
+                // A class factory is allowed to refuse IUnknown-first activation, so a failure
+                // here is not yet an answer: ask for each internal interface directly before
+                // concluding anything.
+                foreach (var (interfaceName, iid, _) in Interfaces)
+                {
+                    var direct = iid;
+                    var dhr = CoCreateInstance(in clsid, IntPtr.Zero, ClsctxAll, in direct, out var instance);
+                    Console.WriteLine($"    direct activation as {interfaceName}: "
+                        + (dhr >= 0 ? "**YES**" : Hresult(dhr)));
+                    if (dhr < 0) continue;
+                    if (interfaceName == "IWSLCSessionManager")
+                    {
+                        bound = true;
+                        if (callThrough) CallThrough(instance);
+                    }
+                    Marshal.Release(instance);
+                }
                 Console.WriteLine();
                 continue;
             }
@@ -227,9 +251,20 @@ internal static class InternalComProbe
 
     // MARK: - Interop
 
+    /// <summary>
+    /// `IID_IUnknown`, spelled out. **Do not** reach for `typeof(object).GUID` here — that is the
+    /// CLR's type GUID for `System.Object`, not `IID_IUnknown`, and activating with it asks every
+    /// class factory for an interface nothing implements. The failure is maximally misleading:
+    /// each registered class answers `E_NOINTERFACE` *at activation*, which reads exactly like
+    /// "this class does not expose the interface you wanted" and is really "you asked for
+    /// gibberish". That mistake produced a false negative on this very probe.
+    /// </summary>
+    private static readonly Guid IidIUnknown = new("00000000-0000-0000-C000-000000000046");
+
     private const uint ClsctxAll = 0x17;          // INPROC_SERVER|HANDLER|LOCAL_SERVER|REMOTE_SERVER
     private const uint CoinitMultithreaded = 0;
     private const uint RpcEChangedMode = 0x80010106;
+    private const uint ENoInterface = 0x80004002;
 
     [DllImport("ole32.dll")]
     private static extern int CoInitializeEx(IntPtr reserved, uint coInit);