Allow users to specify a command to use as remote command instead of
using rcmd directly. This has been in my tree for a long time, but we may need to sync with OpenBSD before MFC. Obtained from: openbsd PR: 15830 MFC after: 2 months
This commit is contained in:
Warner Losh
parent
4f467cb8c1
commit
d45672120f
@ -17,7 +17,7 @@ SRCS+= addr2ascii.c ascii2addr.c base64.c ether_addr.c getaddrinfo.c \
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ns_name.c ns_netint.c \
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ns_ntoa.c ns_parse.c ns_print.c ns_ttl.c \
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nsdispatch.c nslexer.c nsparser.c \
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nsap_addr.c rcmd.c recv.c res_comp.c res_data.c res_debug.c \
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nsap_addr.c rcmd.c rcmdsh.c recv.c res_comp.c res_data.c res_debug.c \
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res_init.c res_mkquery.c res_mkupdate.c res_query.c res_send.c \
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res_update.c rthdr.c send.c vars.c
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# not supported: iso_addr.c
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@ -48,7 +48,7 @@ MAN+= addr2ascii.3 byteorder.3 ethers.3 getaddrinfo.3 gethostbyname.3 \
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if_indextoname.3 \
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inet.3 inet_net.3 \
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inet6_option_space.3 inet6_rthdr_space.3 linkaddr.3 \
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nsdispatch.3 rcmd.3 resolver.3
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nsdispatch.3 rcmd.3 rcmdsh.3 resolver.3
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# not installed: iso_addr.3 ns.3
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MLINKS+=addr2ascii.3 ascii2addr.3
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@ -48,6 +48,7 @@ static char sccsid[] = "@(#)rcmd.c 8.3 (Berkeley) 3/26/94";
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#include <signal.h>
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#include <fcntl.h>
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#include <netdb.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <pwd.h>
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#include <errno.h>
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@ -105,11 +106,29 @@ rcmd_af(ahost, rport, locuser, remuser, cmd, fd2p, af)
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sigset_t oldmask, newmask;
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pid_t pid;
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int s, aport, lport, timo, error;
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char c;
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char c, *p;
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int refused, nres;
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char num[8];
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static char canonnamebuf[MAXDNAME]; /* is it proper here? */
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/* call rcmdsh() with specified remote shell if appropriate. */
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if (!issetugid() && (p = getenv("RSH"))) {
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struct servent *sp = getservbyname("shell", "tcp");
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if (sp && sp->s_port == rport)
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return (rcmdsh(ahost, rport, locuser, remuser,
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cmd, p));
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}
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/* use rsh(1) if non-root and remote port is shell. */
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if (geteuid()) {
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struct servent *sp = getservbyname("shell", "tcp");
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if (sp && sp->s_port == rport)
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return (rcmdsh(ahost, rport, locuser, remuser,
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cmd, NULL));
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}
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pid = getpid();
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memset(&hints, 0, sizeof(hints));
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@ -579,9 +598,6 @@ __ivaliduser_af(hostf, raddr, luser, ruser, af, len)
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return __ivaliduser_sa(hostf, sa, sa->sa_len, luser, ruser);
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}
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/*
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* Returns 0 if ok, -1 if not ok.
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*/
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int
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__ivaliduser_sa(hostf, raddr, salen, luser, ruser)
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FILE *hostf;
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105
lib/libc/net/rcmdsh.3
Normal file
105
lib/libc/net/rcmdsh.3
Normal file
@ -0,0 +1,105 @@
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.\" $OpenBSD: rcmdsh.3,v 1.6 1999/07/05 04:41:00 aaron Exp $
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.\"
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.\" 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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.\" $FreeBSD$
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.\"
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.Dd September 1, 1996
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.Dt RCMDSH 3
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.Os
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.Sh NAME
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.Nm rcmdsh
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.Nd return a stream to a remote command without superuser
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.Sh SYNOPSIS
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.Fd #include <unistd.h>
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.Ft int
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.Fn rcmdsh "char **ahost" "int inport" "const char *locuser" "const char *remuser" "const char *cmd" "char *rshprog"
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.Sh DESCRIPTION
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The
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.Fn rcmdsh
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function
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is used by normal users to execute a command on
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a remote machine using an authentication scheme based
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on reserved port numbers using
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.Xr rshd 8
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or the value of
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.Fa rshprog
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(if non-null).
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.Pp
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The
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.Fn rcmdsh
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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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and a connection is established to a server
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residing at the well-known Internet port
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.Li shell/tcp
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(or whatever port is used by
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.Fa rshprog
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). The parameter
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.Fa inport
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is ignored; it is only included to provide an interface similar to
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.Xr rcmd 3 .
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.Pp
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If the connection succeeds,
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a socket in the
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.Tn UNIX
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domain of type
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.Dv SOCK_STREAM
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is returned to the caller, and given to the remote
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command as stdin and stdout, and stderr.
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.Sh DIAGNOSTICS
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The
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.Fn rcmdsh
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function
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returns a valid socket descriptor on success.
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It returns \-1 on error and prints a diagnostic message on the standard error.
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.Sh SEE ALSO
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.Xr rsh 1 ,
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.Xr socketpair 2 ,
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.Xr rcmd 3 ,
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.Xr rshd 8
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.Sh BUGS
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If
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.Xr rsh 1
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gets an error a file descriptor is still returned instead of \-1.
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.Sh HISTORY
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The
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.Fn rcmdsh
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function first appeared in
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.Ox 2.0 .
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130
lib/libc/net/rcmdsh.c
Normal file
130
lib/libc/net/rcmdsh.c
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@ -0,0 +1,130 @@
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/* $OpenBSD: rcmdsh.c,v 1.5 1998/04/25 16:23:58 millert Exp $ */
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/*
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* This is an rcmd() replacement originally by
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* Chris Siebenmann <cks@utcc.utoronto.ca>.
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*
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* $FreeBSD$
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*/
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#if defined(LIBC_SCCS) && !defined(lint)
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static char *rcsid = "$FreeBSD$"
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#endif /* LIBC_SCCS and not lint */
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <sys/wait.h>
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#include <signal.h>
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#include <errno.h>
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#include <netdb.h>
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#include <stdio.h>
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#include <string.h>
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#include <pwd.h>
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#include <paths.h>
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#include <unistd.h>
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#ifndef _PATH_RSH
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#define _PATH_RSH "/usr/bin/rsh"
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#endif
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/*
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* This is a replacement rcmd() function that uses the rsh(1)
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* program in place of a direct rcmd(3) function call so as to
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* avoid having to be root. Note that rport is ignored.
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*/
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/* ARGSUSED */
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int
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rcmdsh(ahost, rport, locuser, remuser, cmd, rshprog)
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char **ahost;
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int rport;
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const char *locuser, *remuser, *cmd;
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char *rshprog;
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{
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struct hostent *hp;
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int cpid, sp[2];
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char *p;
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struct passwd *pw;
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/* What rsh/shell to use. */
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if (rshprog == NULL)
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rshprog = _PATH_RSH;
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/* locuser must exist on this host. */
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if ((pw = getpwnam(locuser)) == NULL) {
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(void) fprintf(stderr, "rcmdsh: unknown user: %s\n", locuser);
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return(-1);
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}
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/* Validate remote hostname. */
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if (strcmp(*ahost, "localhost") != 0) {
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if ((hp = gethostbyname(*ahost)) == NULL) {
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herror(*ahost);
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return(-1);
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}
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*ahost = hp->h_name;
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}
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/* Get a socketpair we'll use for stdin and stdout. */
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if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, sp) < 0) {
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perror("rcmdsh: socketpair");
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return(-1);
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}
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cpid = fork();
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if (cpid < 0) {
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perror("rcmdsh: fork failed");
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return(-1);
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} else if (cpid == 0) {
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/*
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* Child. We use sp[1] to be stdin/stdout, and close sp[0].
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*/
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(void) close(sp[0]);
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if (dup2(sp[1], 0) < 0 || dup2(0, 1) < 0) {
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perror("rcmdsh: dup2 failed");
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_exit(255);
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}
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/* Fork again to lose parent. */
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cpid = fork();
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if (cpid < 0) {
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perror("rcmdsh: fork to lose parent failed");
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_exit(255);
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}
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if (cpid > 0)
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_exit(0);
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/* In grandchild here. Become local user for rshprog. */
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if (setuid(pw->pw_uid)) {
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(void) fprintf(stderr, "rcmdsh: setuid(%u): %s\n",
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pw->pw_uid, strerror(errno));
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_exit(255);
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}
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/*
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* If remote host is "localhost" and local and remote user
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* are the same, avoid running remote shell for efficiency.
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*/
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if (!strcmp(*ahost, "localhost") && !strcmp(locuser, remuser)) {
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if (pw->pw_shell[0] == '\0')
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rshprog = _PATH_BSHELL;
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else
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rshprog = pw->pw_shell;
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p = strrchr(rshprog, '/');
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execlp(rshprog, p ? p+1 : rshprog, "-c", cmd,
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(char *) NULL);
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} else {
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p = strrchr(rshprog, '/');
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execlp(rshprog, p ? p+1 : rshprog, *ahost, "-l",
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remuser, cmd, (char *) NULL);
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}
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(void) fprintf(stderr, "rcmdsh: execlp %s failed: %s\n",
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rshprog, strerror(errno));
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_exit(255);
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} else {
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/* Parent. close sp[1], return sp[0]. */
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(void) close(sp[1]);
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/* Reap child. */
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(void) wait(NULL);
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return(sp[0]);
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}
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/* NOTREACHED */
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}
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