rexecd(1M) rexecd(1M)
NAME
rexecd - remote execution server
SYNOPSIS
in.rexecd host.port
DESCRIPTION
The rexecd command is the server for the rexec(3N) routine.
The server provides remote execution facilities with
authentication based on user names and encrypted passwords.
Diagnostics
All diagnostic messages are returned on the connection
associated with the stderr, after which any network
connections are closed. An error is indicated by a leading
byte with a value of 1; the value 0 is returned in step 7
below upon successful completion of all the steps prior to the
command execution.
username too long
The name is longer than 16 characters.
password too long
The password is longer than 16 characters.
command too long
The command line passed exceeds the size of the argument
list (as configured into the system).
Login incorrect.
No password file entry for the user name existed.
Password incorrect.
The wrong password was supplied.
No remote directory.
The chdir command to the home directory failed.
Try again.
A fork by the server failed.
/usr/bin/sh: ...
The user's login shell could not be started.
Copyright 1994 Novell, Inc. Page 1
rexecd(1M) rexecd(1M)
USAGE
rexecd is invoked automatically as needed by inetd(1M), and
then executes the following protocol:
1) The server reads characters from the socket up to a null
(\0) byte. The resultant string is interpreted as an
ASCII number, base 10.
2) If the number received in step 1 is non-zero, it is
interpreted as the port number of a secondary stream to
be used for the stderr. A second connection is then
created to the specified port on the client's machine.
3) A null terminated user name of at most 16 characters is
retrieved on the initial socket.
4) A null terminated, encrypted, password of at most 16
characters is retrieved on the initial socket.
5) A null terminated command to be passed to a shell is
retrieved on the initial socket. The length of the
command is limited by the upper bound on the size of the
system's argument list.
6) rexecd then validates the user as is done at login time
and, if the authentication was successful, changes to
the user's home directory, and establishes the user and
group protections of the user. If any of these steps
fail the connection is aborted with a diagnostic message
returned.
7) A null byte is returned on the connection associated
with the stderr and the command line is passed to the
normal login shell of the user. The shell inherits the
network connections established by rexecd.
REFERENCES
inetd(1M)
NOTICES
Indicating Login incorrect as opposed to Password incorrect is
a security breach which allows people to probe a system for
users with null passwords.
Copyright 1994 Novell, Inc. Page 2
rexecd(1M) rexecd(1M)
A facility to allow all data exchanges to be encrypted should
be present.
Copyright 1994 Novell, Inc. Page 3