[Fix] (Remote): offer inproc no shared images and refuse them on its server

MobileGL/MG_Remote/Server/PipeApplier.cpp

@@ -390,6 +390,9 @@ namespace MobileGL::MG_Remote::Server {
         ServerSession* session = ServerSession::Active();
         if (session == nullptr) return false;
         SI::SessionHolder& holder = session->SharedImageHolder();
+        // Shared images carry memory between processes. A client in this process has none to
+        // carry, so it gets none - no platform buffer is ever allocated or imported for it.
+        const Bool peerIsThisProcess = Transport::PeerIsThisProcess(session->ControlTransport());
         const auto fill = [&reply](const SI::Image& image) {
             reply.ImageId = image.Id;
             reply.Modifier = image.Modifier;
@@ -403,6 +406,10 @@ namespace MobileGL::MG_Remote::Server {
         };
         switch (op.Op) {
         case MG_Pipe::kMGPSharedImageAllocate: {
+            if (peerIsThisProcess) {
+                MGLOG_W_ONCE("MG_Remote server: a shared-image allocation was refused: the client is this process");
+                return false;
+            }
             std::string why;
             SI::ImageRef image = SI::Allocate(op.Width, op.Height, op.Format, why);
             if (image == nullptr) {
@@ -436,6 +443,13 @@ namespace MobileGL::MG_Remote::Server {
                         static_cast<unsigned long long>(seq), why.c_str());
                 return false;
             }
+            if (peerIsThisProcess) {
+#if !defined(_WIN32)
+                ::close(fd);
+#endif
+                MGLOG_W_ONCE("MG_Remote server: a dma-buf import was refused: the client is this process");
+                return false;
+            }
             SI::ImageRef image = SI::Identify(fd, why);
             // YUV: the planes and colour hints ride in Damage (MGPImportPlaneWord). A buffer this
             // server did not allocate is taken too, through the labelled CPU-copy fallback

MobileGL/MG_Remote/Server/ServerSession.cpp

@@ -1160,8 +1160,7 @@ namespace MobileGL::MG_Remote::Server {
         // stores' own mappings, donated as monolith donates them, and no AHardwareBuffer, import
         // or POST is involved. A backend that cannot donate leaves the session on T2 - an
         // in-process session never takes the AHardwareBuffer arm below.
-        const Bool inProcess = m_transport != nullptr &&
-            Transport::AdoptT0::PeerIsThisProcess(m_transport->Role() == Transport::TransportRole::InProcess);
+        const Bool inProcess = Transport::PeerIsThisProcess(m_transport);
         if (inProcess) {
             const MG_Pipe::MGPipeResourceOps* ops = MG_Pipe::MGPipeGetResourceOps();
             if (MG_Config::Ipc.AllowAdoptT0 == 0) {