1 /* $OpenBSD: rcmdsh.c,v 1.5 1998/04/25 16:23:58 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 #define _PATH_RSH "/usr/bin/rsh"
57 * This is a replacement rcmd() function that uses the rsh(1)
58 * program in place of a direct rcmd(3) function call so as to
59 * avoid having to be root. Note that rport is ignored.
62 rcmdsh(ahost, rport, locuser, remuser, cmd, rshprog)
65 const char *locuser, *remuser, *cmd, *rshprog;
67 struct addrinfo hints, *res;
68 int cpid, sp[2], error;
72 static char hbuf[NI_MAXHOST];
74 /* What rsh/shell to use. */
78 /* locuser must exist on this host. */
79 if ((pw = getpwnam(locuser)) == NULL) {
80 (void)fprintf(stderr, "rcmdsh: unknown user: %s\n", locuser);
84 /* Validate remote hostname. */
85 if (strcmp(*ahost, "localhost") != 0) {
86 memset(&hints, 0, sizeof(hints));
87 hints.ai_flags = AI_CANONNAME;
88 hints.ai_family = PF_UNSPEC;
89 hints.ai_socktype = SOCK_STREAM;
90 (void)snprintf(num, sizeof(num), "%u",
91 (unsigned int)ntohs(rport));
92 error = getaddrinfo(*ahost, num, &hints, &res);
94 fprintf(stderr, "rcmdsh: getaddrinfo: %s\n",
98 if (res->ai_canonname) {
99 strncpy(hbuf, res->ai_canonname, sizeof(hbuf) - 1);
100 hbuf[sizeof(hbuf) - 1] = '\0';
106 /* Get a socketpair we'll use for stdin and stdout. */
107 if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, sp) == -1) {
108 perror("rcmdsh: socketpair");
114 perror("rcmdsh: fork failed");
116 } else if (cpid == 0) {
118 * Child. We use sp[1] to be stdin/stdout, and close sp[0].
121 if (dup2(sp[1], 0) == -1 || dup2(0, 1) == -1) {
122 perror("rcmdsh: dup2 failed");
125 /* Fork again to lose parent. */
128 perror("rcmdsh: fork to lose parent failed");
134 /* In grandchild here. Become local user for rshprog. */
135 if (setuid(pw->pw_uid) == -1) {
136 (void)fprintf(stderr, "rcmdsh: setuid(%u): %s\n",
137 pw->pw_uid, strerror(errno));
142 * If remote host is "localhost" and local and remote users
143 * are the same, avoid running remote shell for efficiency.
145 if (strcmp(*ahost, "localhost") == 0 &&
146 strcmp(locuser, remuser) == 0) {
147 if (pw->pw_shell[0] == '\0')
148 rshprog = _PATH_BSHELL;
150 rshprog = pw->pw_shell;
151 p = strrchr(rshprog, '/');
152 execlp(rshprog, p ? p + 1 : rshprog, "-c", cmd,
155 p = strrchr(rshprog, '/');
156 execlp(rshprog, p ? p + 1 : rshprog, *ahost, "-l",
157 remuser, cmd, (char *)NULL);
159 (void)fprintf(stderr, "rcmdsh: execlp %s failed: %s\n",
160 rshprog, strerror(errno));
163 /* Parent. close sp[1], return sp[0]. */