We are currently inconsistently handling errors in recv() when flushing data from a TCP socket. In one case, we handle the graceful close, but not the error case. In the other, we handle exactly the opposite.
Both of these loops may spin indefinitely depending on the recv value from the remote server. In one, if the TCP connection is abruptly closed in stageless meterpreter or on a transport switch, the flush function may loop. In the other, if the remote server does a socket shutdown, but not a close, we will also loop.
This changeset fixes an issue with POSIX failing to keep track of loaded
extensions properly. The timeout calcs for waiting were trying to be too
smart and hence were simplified.
Also added another flush when reconnecting so that the body of the
second instance of metsrv is ignored by the POSIX side. In future, when
stageless meterpreter works with POSIX, we won't have to do this.
Currently, the select timeout on the server socket is 100 ns, meaning that
while idle, the process can wake up 100k times per second. This switches the
timeout to 0.5 second, reducing the idle CPU usage and seemingly increasing
the reliability of posix meterpreter as well.
Tested with various test post test modules without failures.
Querying of the status of SSL cert verification is now possible. This commit allows for this to be enabled and disabled on the fly.
Also include some code tidy/refactoring.
The transport refactor appears to be working, but the transport swtching
requires more work on the side of stageless posix before it will work.
At the moment, the POSIX implementation of the transport switching is
commented out so that it can't be used or built into the binaries.
This should mean we can move forward on other friends without this
holding us back.
