The SECURITY_ATTRIBUTES struct and CreateNamedPipe()

Question

My scenario is the following: the process that creates the named pipe object with CreateNamedPipe() has administrator privileges, but the client process \"connectin

Answer 1

Here's your problem:

ea[0].grfAccessPermissions = STANDARD_RIGHTS_ALL;

STANDARD_RIGHTS_ALL is not all rights, only all standard rights, i.e., delete, read control, synchronize, write DAC, and write owner. In particular it does not grant FILE_READ_DATA or FILE_WRITE_DATA, which a client needs in order to read and/or write data to the pipe.

I'd recommend

ea[0].grfAccessPermissions = GENERIC_READ | FILE_WRITE_DATA;

and have the client request the same access rights when opening the pipe. (Obviously, you can leave out the FILE_WRITE_DATA right if this is an outbound pipe, although in that case the default permissions should be OK.)