Open System Services Shell and Utilities Reference Manual (G06.27+, H06.04+)

rexecd(8) OSS Shell and Utilities Reference Manual
NAME
rexecd - Starts the remote execution server
SYNOPSIS
rexecd
DESCRIPTION
rexecd is the local server for the rexec() function available on remote UNIX systems. The server
provides remote execution facilities with authentication based on user names and passwords.
rexecd listens for service requests at the port indicated in the exec service specification of the
/etc/services file. When a service request is received, the following steps occur:
1. The server reads characters from the socket up to a NUL byte. The resultant string is
interpreted as an ASCII number, base 10.
2. If the number received in step 1 is nonzero, it is interpreted as the port number of a secon-
dary stream to be used for the standard error file. A second connection is then created to
the specified port on the client’s machine.
3. A NUL-terminated user name of at most 80 characters is retrieved on the initial socket.
4. A NUL-terminated, unencrypted password of at most 80 characters is retrieved on the ini-
tial socket.
5. A NUL-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 suc-
cessful, changes to the user’s home directory, and establishes the user and group protec-
tions of the user. If any of these steps fails, the connection is aborted with a diagnostic
message returned.
7. A NUL byte is returned on the initial socket, and the command line is passed to the nor-
mal login shell of the user. The shell inherits the network connections established by rex-
ecd.
FILES
/etc/inetd.conf The default file containing the configuration and startup information for the rex-
ecd process.
NOTES
To start the rexecd process, add the following entry to the configuration file for the inetd process:
exec stream tcp nowait super.super /bin/rexecd
(The default configuration file for inetd is /etc/inetd.conf.) Then refresh the inetd configuration
by restarting inetd or by sending it a SIGHUP signal.
DIAGNOSTICS
Except for the last message listed below, all diagnostic messages are returned on the initial socket,
after which any network connections are closed. An error is indicated by a leading byte with a
value of 1 (zero is returned in step 7, above, upon successful completion of all the steps prior to
the command execution).
username too long
The name is longer than 80 characters.
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