scp not tolerant of extraneous shell messages

[Nicolas Williams]

On Tue, Jul 02, 2002 at 08:13:57PM +0000, Bryan Henderson wrote:
> I haven't used sftp, but I see the same thing Dan does in the code:
> when you use a subsystem such as sftp, there's no shell.  I note that it
> is possible to use sftp without a subsystem, though, by specifying the
> sftp server program on the sftp command, and in that case the server
> program runs under a shell just like scp.  

See session.c:session_subsystem_req(), which calls session.c:do_exec(),
which calls session.c:do_exec_no_pty() which calls session.c:do_child(),
which, at the very end does this if the session is non-interactive (or,
rather, if the variable "command" has a non-null value):

        argv[0] = (char *) cp;
        argv[1] = "-c";
        argv[2] = (char *) command;
        argv[3] = NULL;
        execve(shell, argv, env);
        perror(shell);
        exit(1);

So sub-system servers are executed via a shell - the user's shell.

Cheers,

Nico
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