RpcImpersonateNamedPipeClient

[Seiichi Tatsukawa]

| i think i have a possible reason why microsoft implements DCE/RPC
| daemons as the SYSTEM cotnext (whatever) and only calls RpcImpNPC
| if needed. it's because the implementation of this call takes TOO
| DAMN LONG on nt to be called for every single function call.

Look, DCE/RPC was developed on the operating system which had no native
thread support, thus no security context per thread. That system "Unix"
had (still has) the process-wide security context only. DCE/RPC server
runtime was multi-threaded, but the client security context (delegation
and impersonation), obtained by rpc_binding_inq_auth_caller() (or
rpc_binding_inq_auth_client()), was only used by DCE APIs, not by Unix's
native APIs (e.g., file-system access, etc.).

It's up to the server application writer to decide whether to use the
client context or not. MSRPC simply follows this model. (Obviously, MSRPC
has better integration with OS because Win32 APIs can use the client
security context once the server thread impersonates the client.)

---  Seiichi