OpenSSH server stops returning data from a server module

Norbert Sendetzky
Wed, 10 Apr 2002 16:26:15 -0000

Hi all

I've written a client/server application using OpenSSH for securing
the transactions. The server is written as OpenSSH server module
(same as sftp) while the client is a seperate application invoking
the ssh client. My application and the ssh client are connected by
socketpairs the same way as the OpenSSH server and the server module
are.

After the connection between the ssh client and the server is
established, the user is authenticated and the server module is
loaded, the application starts sending messages to the server module.
The server module then responds to the former request. After around
1K of data returned by the server module, the OpenSSH server stops
forwarding the data returned by the server module, so the failure is
deterministic.

I've done several tests to exclude a mistake made by myself. The
server module and the client application seperately work correctly on
the same data. If I connect the client and the server module directly
by replacing the execution of the ssh client in the client
application with the execution of the server module, then there is no
problem at all.

My tests have shown this behaviour from OpenSSH version 2.9 to 3.1.
Is there any known problem related to this observation?

TIA


Norbert