1 /* $NetBSD: rexecd.c,v 1.10 2002/05/26 00:02:08 wiz 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 1.10 2002/05/26 00:02:08 wiz Exp $"); 44 #endif 45 #endif /* not lint */ 46 47 #include <sys/param.h> 48 #include <sys/ioctl.h> 49 #include <sys/poll.h> 50 #include <sys/socket.h> 51 #include <sys/syslog.h> 52 #include <sys/time.h> 53 54 #include <netinet/in.h> 55 56 #include <err.h> 57 #include <errno.h> 58 #include <netdb.h> 59 #include <paths.h> 60 #include <pwd.h> 61 #include <signal.h> 62 #include <stdarg.h> 63 #include <stdio.h> 64 #include <stdlib.h> 65 #include <string.h> 66 #include <unistd.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_in *)); 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 log; 81 struct sockaddr_in asin = { AF_INET }; 82 83 /* 84 * remote execute server: 85 * username\0 86 * password\0 87 * command\0 88 * data 89 */ 90 int 91 main(argc, argv) 92 int argc; 93 char **argv; 94 { 95 struct sockaddr_in from; 96 int fromlen, ch; 97 98 while ((ch = getopt(argc, argv, "l")) != -1) 99 switch (ch) { 100 case 'l': 101 log = 1; 102 openlog("rexecd", LOG_PID, LOG_DAEMON); 103 break; 104 default: 105 exit(1); 106 } 107 108 fromlen = sizeof (from); 109 if (getpeername(0, (struct sockaddr *)&from, &fromlen) < 0) 110 err(1, "getpeername"); 111 112 doit(0, &from); 113 exit(0); 114 } 115 116 void 117 doit(f, fromp) 118 int f; 119 struct sockaddr_in *fromp; 120 { 121 struct pollfd fds[2]; 122 char cmdbuf[NCARGS+1], *namep; 123 const char *cp; 124 char user[16], pass[16]; 125 char buf[BUFSIZ], sig; 126 struct passwd *pwd; 127 int s = -1; /* XXX gcc */ 128 int pv[2], pid, cc; 129 int one = 1; 130 in_port_t port; 131 132 (void)signal(SIGINT, SIG_DFL); 133 (void)signal(SIGQUIT, SIG_DFL); 134 (void)signal(SIGTERM, SIG_DFL); 135 dup2(f, 0); 136 dup2(f, 1); 137 dup2(f, 2); 138 (void)alarm(60); 139 port = 0; 140 for (;;) { 141 char c; 142 if (read(f, &c, 1) != 1) { 143 if (log) 144 syslog(LOG_ERR, 145 "initial read failed"); 146 exit(1); 147 } 148 if (c == 0) 149 break; 150 port = port * 10 + c - '0'; 151 } 152 (void)alarm(0); 153 if (port != 0) { 154 s = socket(AF_INET, SOCK_STREAM, 0); 155 if (s < 0) { 156 if (log) 157 syslog(LOG_ERR, "socket: %m"); 158 exit(1); 159 } 160 if (bind(s, (struct sockaddr *)&asin, sizeof (asin)) < 0) { 161 if (log) 162 syslog(LOG_ERR, "bind: %m"); 163 exit(1); 164 } 165 (void)alarm(60); 166 fromp->sin_port = htons(port); 167 if (connect(s, (struct sockaddr *)fromp, sizeof (*fromp)) < 0) { 168 if (log) 169 syslog(LOG_ERR, "connect: %m"); 170 exit(1); 171 } 172 (void)alarm(0); 173 } 174 getstr(user, sizeof(user), "username"); 175 getstr(pass, sizeof(pass), "password"); 176 getstr(cmdbuf, sizeof(cmdbuf), "command"); 177 setpwent(); 178 pwd = getpwnam(user); 179 if (pwd == NULL) { 180 error("Login incorrect.\n"); 181 if (log) 182 syslog(LOG_ERR, "no such user %s", user); 183 exit(1); 184 } 185 endpwent(); 186 if (*pwd->pw_passwd != '\0') { 187 namep = crypt(pass, pwd->pw_passwd); 188 if (strcmp(namep, pwd->pw_passwd)) { 189 error("Password incorrect.\n"); /* XXX: wrong! */ 190 if (log) 191 syslog(LOG_ERR, "incorrect password for %s", 192 user); 193 exit(1); 194 } 195 } else 196 (void)crypt("dummy password", "PA"); /* must always crypt */ 197 if (chdir(pwd->pw_dir) < 0) { 198 error("No remote directory.\n"); 199 if (log) 200 syslog(LOG_ERR, "%s does not exist for %s", pwd->pw_dir, 201 user); 202 exit(1); 203 } 204 (void)write(2, "\0", 1); 205 if (port) { 206 if (pipe(pv) < 0 || (pid = fork()) == -1) { 207 error("Try again.\n"); 208 if (log) 209 syslog(LOG_ERR,"pipe or fork failed for %s: %m", 210 user); 211 exit(1); 212 } 213 if (pid) { 214 (void)close(0); 215 (void)close(1); 216 (void)close(2); 217 (void)close(f); 218 (void)close(pv[1]); 219 fds[0].fd = s; 220 fds[1].fd = pv[0]; 221 fds[0].events = fds[1].events = POLLIN; 222 if (ioctl(pv[1], FIONBIO, (char *)&one) < 0) 223 _exit(1); 224 /* should set s nbio! */ 225 do { 226 if (poll(fds, 2, 0) < 0) { 227 close(s); 228 close(pv[0]); 229 _exit(1); 230 } 231 if (fds[0].revents & POLLIN) { 232 if (read(s, &sig, 1) <= 0) 233 fds[0].events = 0; 234 else 235 killpg(pid, sig); 236 } 237 if (fds[1].revents & POLLIN) { 238 cc = read(pv[0], buf, sizeof (buf)); 239 if (cc <= 0) { 240 shutdown(s, 1+1); 241 fds[1].events = 0; 242 } else 243 (void)write(s, buf, cc); 244 } 245 } while ((fds[0].events | fds[1].events) & POLLIN); 246 _exit(0); 247 } 248 (void)setpgrp(0, getpid()); 249 (void)close(s); 250 (void)close(pv[0]); 251 if (dup2(pv[1], 2) < 0) { 252 error("Try again.\n"); 253 if (log) 254 syslog(LOG_ERR, "dup2 failed for %s", user); 255 exit(1); 256 } 257 } 258 if (*pwd->pw_shell == '\0') 259 pwd->pw_shell = _PATH_BSHELL; 260 if (f > 2) 261 (void)close(f); 262 if (setlogin(pwd->pw_name) < 0 || 263 initgroups(pwd->pw_name, pwd->pw_gid) < 0 || 264 setgid((gid_t)pwd->pw_gid) < 0 || 265 setuid((uid_t)pwd->pw_uid) < 0) { 266 error("Try again.\n"); 267 if (log) 268 syslog(LOG_ERR, "could not set permissions for %s: %m", 269 user); 270 exit(1); 271 } 272 (void)strcat(path, _PATH_DEFPATH); 273 environ = envinit; 274 strncat(homedir, pwd->pw_dir, sizeof(homedir) - 6); 275 strncat(shell, pwd->pw_shell, sizeof(shell) - 7); 276 strncat(username, pwd->pw_name, sizeof(username) - 6); 277 cp = strrchr(pwd->pw_shell, '/'); 278 if (cp) 279 cp++; 280 else 281 cp = pwd->pw_shell; 282 if (log) 283 syslog(LOG_INFO, "running command for %s: %s", user, cmdbuf); 284 execl(pwd->pw_shell, cp, "-c", cmdbuf, 0); 285 perror(pwd->pw_shell); 286 if (log) 287 syslog(LOG_ERR, "execl failed for %s: %m", user); 288 exit(1); 289 } 290 291 void 292 error(const char *fmt, ...) 293 { 294 char buf[BUFSIZ]; 295 va_list ap; 296 297 va_start(ap, fmt); 298 buf[0] = 1; 299 (void)vsnprintf(buf+1, sizeof(buf) - 1, fmt, ap); 300 (void)write(2, buf, strlen(buf)); 301 va_end(ap); 302 } 303 304 void 305 getstr(buf, cnt, err) 306 char *buf; 307 int cnt; 308 char *err; 309 { 310 char c; 311 312 do { 313 if (read(0, &c, 1) != 1) 314 exit(1); 315 *buf++ = c; 316 if (--cnt == 0) { 317 error("%s too long\n", err); 318 exit(1); 319 } 320 } while (c != 0); 321 } 322