1 /* $NetBSD: rexecd.c,v 1.14 2002/12/06 02:01:35 thorpej 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 1.14 2002/12/06 02:01:35 thorpej 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/syslog.h> 51 #include <sys/time.h> 52 53 #include <netinet/in.h> 54 55 #include <err.h> 56 #include <errno.h> 57 #include <netdb.h> 58 #include <paths.h> 59 #include <pwd.h> 60 #include <signal.h> 61 #include <stdarg.h> 62 #include <stdio.h> 63 #include <stdlib.h> 64 #include <string.h> 65 #include <unistd.h> 66 #include <poll.h> 67 68 void error __P((const char *, ...)) 69 __attribute__((__format__(__printf__, 1, 2))); 70 int main __P((int, char **)); 71 void doit __P((int, struct sockaddr *)); 72 void getstr __P((char *, int, char *)); 73 74 char username[32 + 1] = "USER="; 75 char homedir[PATH_MAX + 1] = "HOME="; 76 char shell[PATH_MAX + 1] = "SHELL="; 77 char path[sizeof(_PATH_DEFPATH) + sizeof("PATH=")] = "PATH="; 78 char *envinit[] = { homedir, shell, path, username, 0 }; 79 char **environ; 80 int dolog; 81 82 /* 83 * remote execute server: 84 * username\0 85 * password\0 86 * command\0 87 * data 88 */ 89 int 90 main(argc, argv) 91 int argc; 92 char **argv; 93 { 94 struct sockaddr_storage from; 95 int fromlen, ch; 96 97 while ((ch = getopt(argc, argv, "l")) != -1) 98 switch (ch) { 99 case 'l': 100 dolog = 1; 101 openlog("rexecd", LOG_PID, LOG_DAEMON); 102 break; 103 default: 104 exit(1); 105 } 106 107 fromlen = sizeof (from); 108 if (getpeername(0, (struct sockaddr *)&from, &fromlen) < 0) 109 err(1, "getpeername"); 110 111 doit(0, (struct sockaddr *)&from); 112 exit(0); 113 } 114 115 void 116 doit(f, fromp) 117 int f; 118 struct sockaddr *fromp; 119 { 120 struct pollfd fds[2]; 121 char cmdbuf[NCARGS+1], *namep; 122 const char *cp; 123 char user[16], pass[16]; 124 char buf[BUFSIZ], sig; 125 struct passwd *pwd; 126 int s = -1; /* XXX gcc */ 127 int pv[2], pid, cc; 128 int one = 1; 129 in_port_t port; 130 131 (void)signal(SIGINT, SIG_DFL); 132 (void)signal(SIGQUIT, SIG_DFL); 133 (void)signal(SIGTERM, SIG_DFL); 134 dup2(f, 0); 135 dup2(f, 1); 136 dup2(f, 2); 137 (void)alarm(60); 138 port = 0; 139 for (;;) { 140 char c; 141 if (read(f, &c, 1) != 1) { 142 if (dolog) 143 syslog(LOG_ERR, 144 "initial read failed"); 145 exit(1); 146 } 147 if (c == 0) 148 break; 149 port = port * 10 + c - '0'; 150 } 151 (void)alarm(0); 152 if (port != 0) { 153 s = socket(fromp->sa_family, SOCK_STREAM, 0); 154 if (s < 0) { 155 if (dolog) 156 syslog(LOG_ERR, "socket: %m"); 157 exit(1); 158 } 159 (void)alarm(60); 160 switch (fromp->sa_family) { 161 case AF_INET: 162 ((struct sockaddr_in *)fromp)->sin_port = htons(port); 163 break; 164 case AF_INET6: 165 ((struct sockaddr_in6 *)fromp)->sin6_port = htons(port); 166 break; 167 default: 168 syslog(LOG_ERR, "unsupported address family"); 169 exit(1); 170 } 171 if (connect(s, (struct sockaddr *)fromp, fromp->sa_len) < 0) { 172 if (dolog) 173 syslog(LOG_ERR, "connect: %m"); 174 exit(1); 175 } 176 (void)alarm(0); 177 } 178 getstr(user, sizeof(user), "username"); 179 getstr(pass, sizeof(pass), "password"); 180 getstr(cmdbuf, sizeof(cmdbuf), "command"); 181 setpwent(); 182 pwd = getpwnam(user); 183 if (pwd == NULL) { 184 error("Login incorrect.\n"); 185 if (dolog) 186 syslog(LOG_ERR, "no such user %s", user); 187 exit(1); 188 } 189 endpwent(); 190 if (*pwd->pw_passwd != '\0') { 191 namep = crypt(pass, pwd->pw_passwd); 192 if (strcmp(namep, pwd->pw_passwd)) { 193 error("Password incorrect.\n"); /* XXX: wrong! */ 194 if (dolog) 195 syslog(LOG_ERR, "incorrect password for %s", 196 user); 197 exit(1); 198 } 199 } else 200 (void)crypt("dummy password", "PA"); /* must always crypt */ 201 if (chdir(pwd->pw_dir) < 0) { 202 error("No remote directory.\n"); 203 if (dolog) 204 syslog(LOG_ERR, "%s does not exist for %s", pwd->pw_dir, 205 user); 206 exit(1); 207 } 208 (void)write(2, "\0", 1); 209 if (port) { 210 if (pipe(pv) < 0 || (pid = fork()) == -1) { 211 error("Try again.\n"); 212 if (dolog) 213 syslog(LOG_ERR,"pipe or fork failed for %s: %m", 214 user); 215 exit(1); 216 } 217 if (pid) { 218 (void)close(0); 219 (void)close(1); 220 (void)close(2); 221 (void)close(f); 222 (void)close(pv[1]); 223 fds[0].fd = s; 224 fds[1].fd = pv[0]; 225 fds[0].events = fds[1].events = POLLIN; 226 if (ioctl(pv[1], FIONBIO, (char *)&one) < 0) 227 _exit(1); 228 /* should set s nbio! */ 229 do { 230 if (poll(fds, 2, 0) < 0) { 231 close(s); 232 close(pv[0]); 233 _exit(1); 234 } 235 if (fds[0].revents & POLLIN) { 236 if (read(s, &sig, 1) <= 0) 237 fds[0].events = 0; 238 else 239 killpg(pid, sig); 240 } 241 if (fds[1].revents & POLLIN) { 242 cc = read(pv[0], buf, sizeof (buf)); 243 if (cc <= 0) { 244 shutdown(s, 1+1); 245 fds[1].events = 0; 246 } else 247 (void)write(s, buf, cc); 248 } 249 } while ((fds[0].events | fds[1].events) & POLLIN); 250 _exit(0); 251 } 252 (void)setpgrp(0, getpid()); 253 (void)close(s); 254 (void)close(pv[0]); 255 if (dup2(pv[1], 2) < 0) { 256 error("Try again.\n"); 257 if (dolog) 258 syslog(LOG_ERR, "dup2 failed for %s", user); 259 exit(1); 260 } 261 } 262 if (*pwd->pw_shell == '\0') 263 pwd->pw_shell = _PATH_BSHELL; 264 if (f > 2) 265 (void)close(f); 266 if (setlogin(pwd->pw_name) < 0 || 267 initgroups(pwd->pw_name, pwd->pw_gid) < 0 || 268 setgid((gid_t)pwd->pw_gid) < 0 || 269 setuid((uid_t)pwd->pw_uid) < 0) { 270 error("Try again.\n"); 271 if (dolog) 272 syslog(LOG_ERR, "could not set permissions for %s: %m", 273 user); 274 exit(1); 275 } 276 (void)strcat(path, _PATH_DEFPATH); 277 environ = envinit; 278 strncat(homedir, pwd->pw_dir, sizeof(homedir) - 6); 279 strncat(shell, pwd->pw_shell, sizeof(shell) - 7); 280 strncat(username, pwd->pw_name, sizeof(username) - 6); 281 cp = strrchr(pwd->pw_shell, '/'); 282 if (cp) 283 cp++; 284 else 285 cp = pwd->pw_shell; 286 if (dolog) 287 syslog(LOG_INFO, "running command for %s: %s", user, cmdbuf); 288 execl(pwd->pw_shell, cp, "-c", cmdbuf, 0); 289 perror(pwd->pw_shell); 290 if (dolog) 291 syslog(LOG_ERR, "execl failed for %s: %m", user); 292 exit(1); 293 } 294 295 void 296 error(const char *fmt, ...) 297 { 298 char buf[BUFSIZ]; 299 va_list ap; 300 301 va_start(ap, fmt); 302 buf[0] = 1; 303 (void)vsnprintf(buf+1, sizeof(buf) - 1, fmt, ap); 304 (void)write(2, buf, strlen(buf)); 305 va_end(ap); 306 } 307 308 void 309 getstr(buf, cnt, err) 310 char *buf; 311 int cnt; 312 char *err; 313 { 314 char c; 315 316 do { 317 if (read(0, &c, 1) != 1) 318 exit(1); 319 *buf++ = c; 320 if (--cnt == 0) { 321 error("%s too long\n", err); 322 exit(1); 323 } 324 } while (c != 0); 325 } 326