1 /* $NetBSD: rexecd.c,v 1.4 1997/10/07 10:11:31 mrg Exp $ */ 2 3 /* 4 * Copyright (c) 1983, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 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 the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #include <sys/cdefs.h> 37 #ifndef lint 38 __COPYRIGHT("@(#) Copyright (c) 1983, 1993\n\ 39 The Regents of the University of California. All rights reserved.\n"); 40 #if 0 41 static char sccsid[] = "from: @(#)rexecd.c 8.1 (Berkeley) 6/4/93"; 42 #else 43 __RCSID("$NetBSD: rexecd.c,v 1.4 1997/10/07 10:11:31 mrg Exp $"); 44 #endif 45 #endif /* not lint */ 46 47 #include <sys/param.h> 48 #include <sys/ioctl.h> 49 #include <sys/socket.h> 50 #include <sys/time.h> 51 52 #include <netinet/in.h> 53 54 #include <errno.h> 55 #include <netdb.h> 56 #include <paths.h> 57 #include <pwd.h> 58 #include <signal.h> 59 #include <stdio.h> 60 #include <stdlib.h> 61 #include <string.h> 62 #include <unistd.h> 63 64 void error __P((const char *, ...)); 65 int main __P((int, char **)); 66 void doit __P((int, struct sockaddr_in *)); 67 void getstr __P((char *, int, char *)); 68 69 /* 70 * remote execute server: 71 * username\0 72 * password\0 73 * command\0 74 * data 75 */ 76 int 77 main(argc, argv) 78 int argc; 79 char **argv; 80 { 81 struct sockaddr_in from; 82 int fromlen; 83 84 fromlen = sizeof (from); 85 if (getpeername(0, (struct sockaddr *)&from, &fromlen) < 0) { 86 (void)fprintf(stderr, 87 "rexecd: getpeername: %s\n", strerror(errno)); 88 exit(1); 89 } 90 doit(0, &from); 91 exit(0); 92 } 93 94 char username[20] = "USER="; 95 char homedir[64] = "HOME="; 96 char shell[64] = "SHELL="; 97 char path[sizeof(_PATH_DEFPATH) + sizeof("PATH=")] = "PATH="; 98 char *envinit[] = 99 {homedir, shell, path, username, 0}; 100 char **environ; 101 102 struct sockaddr_in asin = { AF_INET }; 103 104 void 105 doit(f, fromp) 106 int f; 107 struct sockaddr_in *fromp; 108 { 109 char cmdbuf[NCARGS+1], *cp, *namep; 110 char user[16], pass[16]; 111 struct passwd *pwd; 112 int s = -1; /* XXX gcc */ 113 u_short port; 114 int pv[2], pid, ready, readfrom, cc; 115 char buf[BUFSIZ], sig; 116 int one = 1; 117 118 (void) signal(SIGINT, SIG_DFL); 119 (void) signal(SIGQUIT, SIG_DFL); 120 (void) signal(SIGTERM, SIG_DFL); 121 #ifdef DEBUG 122 { int t = open(_PATH_TTY, 2); 123 if (t >= 0) { 124 ioctl(t, TIOCNOTTY, (char *)0); 125 (void) close(t); 126 } 127 } 128 #endif 129 dup2(f, 0); 130 dup2(f, 1); 131 dup2(f, 2); 132 (void) alarm(60); 133 port = 0; 134 for (;;) { 135 char c; 136 if (read(f, &c, 1) != 1) 137 exit(1); 138 if (c == 0) 139 break; 140 port = port * 10 + c - '0'; 141 } 142 (void) alarm(0); 143 if (port != 0) { 144 s = socket(AF_INET, SOCK_STREAM, 0); 145 if (s < 0) 146 exit(1); 147 if (bind(s, (struct sockaddr *)&asin, sizeof (asin)) < 0) 148 exit(1); 149 (void) alarm(60); 150 fromp->sin_port = htons(port); 151 if (connect(s, (struct sockaddr *)fromp, sizeof (*fromp)) < 0) 152 exit(1); 153 (void) alarm(0); 154 } 155 getstr(user, sizeof(user), "username"); 156 getstr(pass, sizeof(pass), "password"); 157 getstr(cmdbuf, sizeof(cmdbuf), "command"); 158 setpwent(); 159 pwd = getpwnam(user); 160 if (pwd == NULL) { 161 error("Login incorrect.\n"); 162 exit(1); 163 } 164 endpwent(); 165 if (*pwd->pw_passwd != '\0') { 166 namep = crypt(pass, pwd->pw_passwd); 167 if (strcmp(namep, pwd->pw_passwd)) { 168 error("Password incorrect.\n"); 169 exit(1); 170 } 171 } 172 if (chdir(pwd->pw_dir) < 0) { 173 error("No remote directory.\n"); 174 exit(1); 175 } 176 (void) write(2, "\0", 1); 177 if (port) { 178 (void) pipe(pv); 179 pid = fork(); 180 if (pid == -1) { 181 error("Try again.\n"); 182 exit(1); 183 } 184 if (pid) { 185 (void) close(0); (void) close(1); (void) close(2); 186 (void) close(f); (void) close(pv[1]); 187 readfrom = (1<<s) | (1<<pv[0]); 188 ioctl(pv[1], FIONBIO, (char *)&one); 189 /* should set s nbio! */ 190 do { 191 ready = readfrom; 192 (void) select(16, (fd_set *)&ready, 193 (fd_set *)NULL, (fd_set *)NULL, 194 (struct timeval *)NULL); 195 if (ready & (1<<s)) { 196 if (read(s, &sig, 1) <= 0) 197 readfrom &= ~(1<<s); 198 else 199 killpg(pid, sig); 200 } 201 if (ready & (1<<pv[0])) { 202 cc = read(pv[0], buf, sizeof (buf)); 203 if (cc <= 0) { 204 shutdown(s, 1+1); 205 readfrom &= ~(1<<pv[0]); 206 } else 207 (void) write(s, buf, cc); 208 } 209 } while (readfrom); 210 exit(0); 211 } 212 setpgrp(0, getpid()); 213 (void) close(s); (void)close(pv[0]); 214 dup2(pv[1], 2); 215 } 216 if (*pwd->pw_shell == '\0') 217 pwd->pw_shell = _PATH_BSHELL; 218 if (f > 2) 219 (void) close(f); 220 setlogin(pwd->pw_name); 221 (void) setgid((gid_t)pwd->pw_gid); 222 initgroups(pwd->pw_name, pwd->pw_gid); 223 (void) setuid((uid_t)pwd->pw_uid); 224 (void)strcat(path, _PATH_DEFPATH); 225 environ = envinit; 226 strncat(homedir, pwd->pw_dir, sizeof(homedir)-6); 227 strncat(shell, pwd->pw_shell, sizeof(shell)-7); 228 strncat(username, pwd->pw_name, sizeof(username)-6); 229 cp = strrchr(pwd->pw_shell, '/'); 230 if (cp) 231 cp++; 232 else 233 cp = pwd->pw_shell; 234 execl(pwd->pw_shell, cp, "-c", cmdbuf, 0); 235 perror(pwd->pw_shell); 236 exit(1); 237 } 238 239 #ifdef __STDC__ 240 #include <stdarg.h> 241 #else 242 #include <varargs.h> 243 #endif 244 245 void 246 #ifdef __STDC__ 247 error(const char *fmt, ...) 248 #else 249 error(fmt, va_alist) 250 char *fmt; 251 va_dcl 252 #endif 253 { 254 char buf[BUFSIZ]; 255 va_list ap; 256 257 #ifdef __STDC__ 258 va_start(ap, fmt); 259 #else 260 va_start(ap); 261 #endif 262 263 buf[0] = 1; 264 (void)vsprintf(buf+1, fmt, ap); 265 (void)write(2, buf, strlen(buf)); 266 } 267 268 void 269 getstr(buf, cnt, err) 270 char *buf; 271 int cnt; 272 char *err; 273 { 274 char c; 275 276 do { 277 if (read(0, &c, 1) != 1) 278 exit(1); 279 *buf++ = c; 280 if (--cnt == 0) { 281 error("%s too long\n", err); 282 exit(1); 283 } 284 } while (c != 0); 285 } 286