135 lines
4.2 KiB
Groff
135 lines
4.2 KiB
Groff
.\" Copyright (c) 1983, 1991, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the University of
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.\" California, Berkeley and its contributors.
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.\" 4. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)rexec.3 8.1 (Berkeley) 6/4/93
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.\" $FreeBSD$
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.\"
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.Dd June 4, 1993
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.Dt REXEC 3
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.Os BSD 4.2
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.Sh NAME
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.Nm rexec
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.Nd return stream to a remote command
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.Sh LIBRARY
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.Lb libcompat
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.Sh SYNOPSIS
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.Ft int
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.Fn rexec "char **ahost" "int inport" "char *user" "char *passwd" "char *cmd" "int *fd2p"
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.Sh DESCRIPTION
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.Bf -symbolic
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This interface is obsoleted by
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.Xr rcmd 3 .
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.Ef
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.Pp
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The
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.Fn rexec
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function
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looks up the host
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.Fa *ahost
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using
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.Xr gethostbyname 3 ,
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returning \-1 if the host does not exist.
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Otherwise
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.Fa *ahost
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is set to the standard name of the host.
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If a username and password are both specified, then these
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are used to authenticate to the foreign host; otherwise
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the environment and then the user's
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.Pa .netrc
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file in his
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home directory are searched for appropriate information.
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If all this fails, the user is prompted for the information.
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.Pp
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The port
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.Fa inport
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specifies which well-known
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.Tn DARPA
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Internet port to use for
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the connection; the call
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.Fn getservbyname \*qexec\*q \*qtcp\*q
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(see
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.Xr getservent 3 )
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will return a pointer to a structure, which contains the
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necessary port.
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The protocol for connection is described in detail in
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.Xr rexecd 8 .
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.Pp
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If the connection succeeds,
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a socket in the Internet domain of type
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.Dv SOCK_STREAM
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is returned to
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the caller, and given to the remote command as
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.Em stdin
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and
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.Em stdout .
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If
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.Fa fd2p
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is non-zero, then an auxiliary channel to a control
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process will be setup, and a descriptor for it will be placed
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in
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.Fa *fd2p .
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The control process will return diagnostic
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output from the command (unit 2) on this channel, and will also
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accept bytes on this channel as being
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.Tn UNIX
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signal numbers, to be
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forwarded to the process group of the command. The diagnostic
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information returned does not include remote authorization failure,
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as the secondary connection is set up after authorization has been
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verified.
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If
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.Fa fd2p
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is 0, then the
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.Em stderr
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(unit 2 of the remote
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command) will be made the same as the
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.Em stdout
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and no
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provision is made for sending arbitrary signals to the remote process,
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although you may be able to get its attention by using out-of-band data.
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.Sh SEE ALSO
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.Xr rcmd 3 ,
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.Xr rexecd 8
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.Sh HISTORY
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The
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.Fn rexec
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function appeared in
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.Bx 4.2 .
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.Sh BUGS
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The
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.Fn rexec
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function sends the unencrypted password across the network.
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.Pp
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The underlying service is considered a big security hole and therefore
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not enabled on many sites, see
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.Xr rexecd 8
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for explanations.
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