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59797edfd8
libc now no longer calls fstat(), socketpair() and wait(), only the underscore-prefixed versions (_waitpid() instead of wait()).
168 lines
4.9 KiB
C
168 lines
4.9 KiB
C
/* $OpenBSD: rcmdsh.c,v 1.7 2002/03/12 00:05:44 millert Exp $ */
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/*
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* Copyright (c) 2001, MagniComp
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* 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
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* the documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the MagniComp nor the names of its contributors may
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* 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 COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND 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 FOR
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* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
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* USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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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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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "namespace.h"
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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 <arpa/inet.h>
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#include <errno.h>
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#include <netdb.h>
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#include <paths.h>
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#include <pwd.h>
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#include <stdio.h>
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#include <string.h>
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#include <unistd.h>
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#include "un-namespace.h"
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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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int
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rcmdsh(char **ahost, int rport, const char *locuser, const char *remuser,
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const char *cmd, const char *rshprog)
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{
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struct addrinfo hints, *res;
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int sp[2], error;
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pid_t cpid;
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char *p;
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struct passwd *pw;
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char num[8];
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static char hbuf[NI_MAXHOST];
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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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memset(&hints, 0, sizeof(hints));
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hints.ai_flags = AI_CANONNAME;
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hints.ai_family = PF_UNSPEC;
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hints.ai_socktype = SOCK_STREAM;
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(void)snprintf(num, sizeof(num), "%u",
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(unsigned int)ntohs(rport));
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error = getaddrinfo(*ahost, num, &hints, &res);
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if (error) {
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fprintf(stderr, "rcmdsh: getaddrinfo: %s\n",
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gai_strerror(error));
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return (-1);
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}
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if (res->ai_canonname) {
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strncpy(hbuf, res->ai_canonname, sizeof(hbuf) - 1);
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hbuf[sizeof(hbuf) - 1] = '\0';
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*ahost = hbuf;
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}
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freeaddrinfo(res);
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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) == -1) {
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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 == -1) {
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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) == -1 || _dup2(0, 1) == -1) {
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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 == -1) {
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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) == -1) {
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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 users
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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") == 0 &&
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strcmp(locuser, remuser) == 0) {
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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)_waitpid(cpid, NULL, 0);
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return (sp[0]);
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}
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/* NOTREACHED */
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}
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