Explorer file copies were invisible to the Helper because the service
launched its child with a duplicate of the LocalSystem token and changed
only TokenSessionId. The child therefore remained a System-integrity
process. Windows filtered Explorer's file clipboard formats across that
integrity boundary. Basic text and bitmap formats continued to work.
Keep only the SCM service privileged. Obtain the active session user's
primary token with WTSQueryUserToken. For elevated accounts, prefer the
linked limited token. Validate its session and security properties.
Build the user environment and launch the interactive Helper on
WinSta0\Default. Gate Helper activation until the service has rechecked
the active session and registered the clipboard authority.
Use random lifetime, stop, and activation objects owned by the service.
Give the target logon SID synchronization access only. Recheck the
active console session and service state before activation. Make the
lifetime mutex terminate the Helper if the service exits unexpectedly.
Restart it when the active session, IDD host, or authority changes.
Replace the old process-handle mapping transfer with a device-bound
authority protocol on the LGIdd device interface. The service verifies
the exact driver host instance, duplicates only section map rights into
that process, and registers the session, mapping identifier, and handle.
Bind authority lifetime to its WDF file object, revoke it synchronously
on cleanup, and poll the driver host identity while the child is active.
Restrict the device stack to SYSTEM and isolate LGIdd in a unique UMDF
device group. Restrict the shared section to SYSTEM and the target logon
SID. Apply a medium mandatory label that prevents low-integrity readers
and writers. Map it with read/write rights instead of all access.
Give each clipboard mapping a second random authority identifier. Store
it only inside the logon-SID-protected mapping and send it in the
mandatory HELLO. LGIdd matches it against the service-injected mapping.
This authenticates the user Helper without the unsupported UMDF call to
GetNamedPipeClientSessionId. Have the Helper verify that its pipe server
is in session zero.
Extend the pipe endpoint with bounded authentication reads, cancellable
overlapped I/O, periodic authorization checks, and explicit disconnects.
Serialize authority changes with clipboard attach and detach. Prevent
stale cleanup from tearing down a replacement mapping. Disconnect the
user pipe immediately when its owning authority is revoked.
Run clipboard, OLE, display, configuration, and file access in the
user's interactive process. Retain its process token for worker-thread
file operations instead of querying and impersonating the desktop user
from a System process. Store Helper logs in LocalAppData and grant only
the registry rights needed by interactive configuration and UMDF.
Keep immediate, stage-specific Win32 and HRESULT diagnostics throughout
clipboard capture. Probe CF_HDROP while holding the Win32 clipboard and
enumerate the OLE object's advertised file formats. Validate returned
storage and fall back to Shell item paths when direct retrieval fails.
Validate clipboard sequence changes and defer retries during contention
without publishing incomplete clipboard state.
Complete the 1 MiB transfer work with full-sized Windows copy buffers.
Use full-sized FUSE reads and retain the named 64 KiB X11 chunk limit.
Validate the user-writable mapping with CClipboardRing before attaching.
The pipe, mapping, and authority protocols change together. LGIdd.dll,
the INF, and LGIddHelper.exe must be rebuilt and installed as one
matching set.
Add a protocol-independent recovery channel outside LGMP so clients can
request a usable guest display even when transport versions differ.
Synchronize recovery state with the helper across driver restarts and
restore the configured topology without persisting temporary changes.
Define a fixed, protocol-independent recovery ABI in the final 64 KiB
of IVSHMEM.
Provide crash-safe multi-client requests and coherent producer status.
Exclude the region from LGMP allocation and frame capacity so future
protocol mismatches retain a stable control path.
Make CSRWLock own the native lock and provide scoped guards for shared,
exclusive, early-unlock, and non-blocking use.
Replace direct SRW lock management throughout the IDD, input driver,
and helper while preserving the existing lock scopes.
Move named pipe writes off the LGMP input worker so a stalled LGInput
endpoint cannot block queue draining or lease maintenance.
Coalesce motion only under queue pressure while preserving mode, button,
wheel, and keyboard transitions. Reset HID state after discontinuities
and carry all 32 mouse button bits through the pipe and HID reports.
Add an optional input transport and a dedicated LGMP receiver that
validates source ownership, generations, ordered sequences, and leases.
Poll input outside the 10 ms control timer. Forward mouse and keyboard
state through the LGInput pipe, and neutralize the endpoint before
ownership changes or transport failures can leave input held.
Replace raw HID report forwarding with typed absolute mouse, relative
mouse, and keyboard messages.
Expose absolute and relative modes as separate Mouse collections because
Windows MouHID requires one X/Y motion mode per mouse device.
Move the reusable named-pipe endpoint and shared support code into
the LGCommon static library.
Run a dedicated server in LGIdd and a reconnecting client in
LGInput, with device-lifecycle handling and report framing.
Refactor the helper pipe to use the same endpoint implementation.
Build LGInput as an independent UMDF driver with its own entry point,
service, tracing, and binary.
Expose absolute pointer, relative mouse, and keyboard collections with a
guarded report queue.
Keep LGIdd as the startup and deployment project. Give it a non-linking
build/package dependency on LGInput so F5 stages both driver stacks and
installs them together through LGIddInstall, while the two UMDF binaries
remain independent for future IPC.
Stage both DLLs for the NSIS installer, retain the WDK UMDF remote-debug
startup attachment, and move CSRWLock into LGCommon for the input
driver's report queue.
Use an explicit placed buffer for software frame copies so the D3D copy
uses the same row pitch published through KVMFR.
GetCopyableFootprints describes buffer copies and cannot be used to infer
the physical layout of a placed row-major texture. This caused padded
resolutions to use the wrong row starts in every consumer.
Keep the copy direct to IVSHMEM without a staging or CPU copy.
