1 /* $OpenBSD: rcmdsh.c,v 1.7 2002/03/12 00:05:44 millert Exp $ */
4 * Copyright (c) 2001, MagniComp
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in
14 * the documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the MagniComp nor the names of its contributors may
16 * be used to endorse or promote products derived from this software
17 * without specific prior written permission.
19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
20 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR
23 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
25 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
26 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
27 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
28 * USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 * This is an rcmd() replacement originally by
33 * Chris Siebenmann <cks@utcc.utoronto.ca>.
36 #include <sys/cdefs.h>
37 __FBSDID("$FreeBSD$");
39 #include <sys/types.h>
40 #include <sys/socket.h>
42 #include <arpa/inet.h>
53 * This is a replacement rcmd() function that uses the rsh(1)
54 * program in place of a direct rcmd(3) function call so as to
55 * avoid having to be root. Note that rport is ignored.
58 rcmdsh(char **ahost, int rport, const char *locuser, const char *remuser,
59 const char *cmd, const char *rshprog)
61 struct addrinfo hints, *res;
67 static char hbuf[NI_MAXHOST];
69 /* What rsh/shell to use. */
73 /* locuser must exist on this host. */
74 if ((pw = getpwnam(locuser)) == NULL) {
75 (void)fprintf(stderr, "rcmdsh: unknown user: %s\n", locuser);
79 /* Validate remote hostname. */
80 if (strcmp(*ahost, "localhost") != 0) {
81 memset(&hints, 0, sizeof(hints));
82 hints.ai_flags = AI_CANONNAME;
83 hints.ai_family = PF_UNSPEC;
84 hints.ai_socktype = SOCK_STREAM;
85 (void)snprintf(num, sizeof(num), "%u",
86 (unsigned int)ntohs(rport));
87 error = getaddrinfo(*ahost, num, &hints, &res);
89 fprintf(stderr, "rcmdsh: getaddrinfo: %s\n",
93 if (res->ai_canonname) {
94 strncpy(hbuf, res->ai_canonname, sizeof(hbuf) - 1);
95 hbuf[sizeof(hbuf) - 1] = '\0';
101 /* Get a socketpair we'll use for stdin and stdout. */
102 if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, sp) == -1) {
103 perror("rcmdsh: socketpair");
109 perror("rcmdsh: fork failed");
111 } else if (cpid == 0) {
113 * Child. We use sp[1] to be stdin/stdout, and close sp[0].
116 if (dup2(sp[1], 0) == -1 || dup2(0, 1) == -1) {
117 perror("rcmdsh: dup2 failed");
120 /* Fork again to lose parent. */
123 perror("rcmdsh: fork to lose parent failed");
129 /* In grandchild here. Become local user for rshprog. */
130 if (setuid(pw->pw_uid) == -1) {
131 (void)fprintf(stderr, "rcmdsh: setuid(%u): %s\n",
132 pw->pw_uid, strerror(errno));
137 * If remote host is "localhost" and local and remote users
138 * are the same, avoid running remote shell for efficiency.
140 if (strcmp(*ahost, "localhost") == 0 &&
141 strcmp(locuser, remuser) == 0) {
142 if (pw->pw_shell[0] == '\0')
143 rshprog = _PATH_BSHELL;
145 rshprog = pw->pw_shell;
146 p = strrchr(rshprog, '/');
147 execlp(rshprog, p ? p + 1 : rshprog, "-c", cmd,
150 p = strrchr(rshprog, '/');
151 execlp(rshprog, p ? p + 1 : rshprog, *ahost, "-l",
152 remuser, cmd, (char *)NULL);
154 (void)fprintf(stderr, "rcmdsh: execlp %s failed: %s\n",
155 rshprog, strerror(errno));
158 /* Parent. close sp[1], return sp[0]. */