rexecd.c revision 1.18
1 /* $NetBSD: rexecd.c,v 1.18 2004/05/11 08:07:37 kleink 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. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * 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 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 #ifndef lint 34 __COPYRIGHT("@(#) Copyright (c) 1983, 1993\n\ 35 The Regents of the University of California. All rights reserved.\n"); 36 #if 0 37 static char sccsid[] = "from: @(#)rexecd.c 8.1 (Berkeley) 6/4/93"; 38 #else 39 __RCSID("$NetBSD: rexecd.c,v 1.18 2004/05/11 08:07:37 kleink Exp $"); 40 #endif 41 #endif /* not lint */ 42 43 #include <sys/param.h> 44 #include <sys/ioctl.h> 45 #include <sys/socket.h> 46 #include <sys/syslog.h> 47 #include <sys/time.h> 48 49 #include <netinet/in.h> 50 51 #include <err.h> 52 #include <errno.h> 53 #include <netdb.h> 54 #include <paths.h> 55 #include <pwd.h> 56 #include <signal.h> 57 #include <stdarg.h> 58 #include <stdio.h> 59 #include <stdlib.h> 60 #include <string.h> 61 #include <unistd.h> 62 #include <poll.h> 63 64 void error __P((const char *, ...)) 65 __attribute__((__format__(__printf__, 1, 2))); 66 int main __P((int, char **)); 67 void doit __P((int, struct sockaddr *)); 68 void getstr __P((char *, int, char *)); 69 70 char username[32 + 1] = "USER="; 71 char logname[32 + 3 + 1] = "LOGNAME="; 72 char homedir[PATH_MAX + 1] = "HOME="; 73 char shell[PATH_MAX + 1] = "SHELL="; 74 char path[sizeof(_PATH_DEFPATH) + sizeof("PATH=")] = "PATH="; 75 char *envinit[] = { homedir, shell, path, username, logname, 0 }; 76 char **environ; 77 int dolog; 78 79 /* 80 * remote execute server: 81 * username\0 82 * password\0 83 * command\0 84 * data 85 */ 86 int 87 main(argc, argv) 88 int argc; 89 char **argv; 90 { 91 struct sockaddr_storage from; 92 int fromlen, ch; 93 94 while ((ch = getopt(argc, argv, "l")) != -1) 95 switch (ch) { 96 case 'l': 97 dolog = 1; 98 openlog("rexecd", LOG_PID, LOG_DAEMON); 99 break; 100 default: 101 exit(1); 102 } 103 104 fromlen = sizeof (from); 105 if (getpeername(0, (struct sockaddr *)&from, &fromlen) < 0) 106 err(1, "getpeername"); 107 108 doit(0, (struct sockaddr *)&from); 109 exit(0); 110 } 111 112 void 113 doit(f, fromp) 114 int f; 115 struct sockaddr *fromp; 116 { 117 struct pollfd fds[2]; 118 char cmdbuf[NCARGS+1], *namep; 119 const char *cp; 120 char user[16], pass[16]; 121 char buf[BUFSIZ], sig; 122 struct passwd *pwd; 123 int s = -1; /* XXX gcc */ 124 int pv[2], pid, cc; 125 int one = 1; 126 in_port_t port; 127 128 (void)signal(SIGINT, SIG_DFL); 129 (void)signal(SIGQUIT, SIG_DFL); 130 (void)signal(SIGTERM, SIG_DFL); 131 dup2(f, 0); 132 dup2(f, 1); 133 dup2(f, 2); 134 (void)alarm(60); 135 port = 0; 136 for (;;) { 137 char c; 138 if (read(f, &c, 1) != 1) { 139 if (dolog) 140 syslog(LOG_ERR, 141 "initial read failed"); 142 exit(1); 143 } 144 if (c == 0) 145 break; 146 port = port * 10 + c - '0'; 147 } 148 (void)alarm(0); 149 if (port != 0) { 150 s = socket(fromp->sa_family, SOCK_STREAM, 0); 151 if (s < 0) { 152 if (dolog) 153 syslog(LOG_ERR, "socket: %m"); 154 exit(1); 155 } 156 (void)alarm(60); 157 switch (fromp->sa_family) { 158 case AF_INET: 159 ((struct sockaddr_in *)fromp)->sin_port = htons(port); 160 break; 161 case AF_INET6: 162 ((struct sockaddr_in6 *)fromp)->sin6_port = htons(port); 163 break; 164 default: 165 syslog(LOG_ERR, "unsupported address family"); 166 exit(1); 167 } 168 if (connect(s, (struct sockaddr *)fromp, fromp->sa_len) < 0) { 169 if (dolog) 170 syslog(LOG_ERR, "connect: %m"); 171 exit(1); 172 } 173 (void)alarm(0); 174 } 175 getstr(user, sizeof(user), "username"); 176 getstr(pass, sizeof(pass), "password"); 177 getstr(cmdbuf, sizeof(cmdbuf), "command"); 178 setpwent(); 179 pwd = getpwnam(user); 180 if (pwd == NULL) { 181 error("Login incorrect.\n"); 182 if (dolog) 183 syslog(LOG_ERR, "no such user %s", user); 184 exit(1); 185 } 186 endpwent(); 187 if (*pwd->pw_passwd != '\0') { 188 namep = crypt(pass, pwd->pw_passwd); 189 if (strcmp(namep, pwd->pw_passwd)) { 190 error("Password incorrect.\n"); /* XXX: wrong! */ 191 if (dolog) 192 syslog(LOG_ERR, "incorrect password for %s", 193 user); 194 exit(1); 195 } 196 } else 197 (void)crypt("dummy password", "PA"); /* must always crypt */ 198 if (chdir(pwd->pw_dir) < 0) { 199 error("No remote directory.\n"); 200 if (dolog) 201 syslog(LOG_ERR, "%s does not exist for %s", pwd->pw_dir, 202 user); 203 exit(1); 204 } 205 (void)write(2, "\0", 1); 206 if (port) { 207 if (pipe(pv) < 0 || (pid = fork()) == -1) { 208 error("Try again.\n"); 209 if (dolog) 210 syslog(LOG_ERR,"pipe or fork failed for %s: %m", 211 user); 212 exit(1); 213 } 214 if (pid) { 215 (void)close(0); 216 (void)close(1); 217 (void)close(2); 218 (void)close(f); 219 (void)close(pv[1]); 220 fds[0].fd = s; 221 fds[1].fd = pv[0]; 222 fds[0].events = fds[1].events = POLLIN; 223 if (ioctl(pv[1], FIONBIO, (char *)&one) < 0) 224 _exit(1); 225 /* should set s nbio! */ 226 do { 227 if (poll(fds, 2, 0) < 0) { 228 close(s); 229 close(pv[0]); 230 _exit(1); 231 } 232 if (fds[0].revents & POLLIN) { 233 if (read(s, &sig, 1) <= 0) 234 fds[0].events = 0; 235 else 236 killpg(pid, sig); 237 } 238 if (fds[1].revents & POLLIN) { 239 cc = read(pv[0], buf, sizeof (buf)); 240 if (cc <= 0) { 241 shutdown(s, 1+1); 242 fds[1].events = 0; 243 } else 244 (void)write(s, buf, cc); 245 } 246 } while ((fds[0].events | fds[1].events) & POLLIN); 247 _exit(0); 248 } 249 (void)close(s); 250 (void)close(pv[0]); 251 if (dup2(pv[1], 2) < 0) { 252 error("Try again.\n"); 253 if (dolog) 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 (setsid() < 0 || 263 setlogin(pwd->pw_name) < 0 || 264 initgroups(pwd->pw_name, pwd->pw_gid) < 0 || 265 setgid((gid_t)pwd->pw_gid) < 0 || 266 setuid((uid_t)pwd->pw_uid) < 0) { 267 error("Try again.\n"); 268 if (dolog) 269 syslog(LOG_ERR, "could not set permissions for %s: %m", 270 user); 271 exit(1); 272 } 273 (void)strlcat(path, _PATH_DEFPATH, sizeof(path)); 274 environ = envinit; 275 strlcat(homedir, pwd->pw_dir, sizeof(homedir)); 276 strlcat(shell, pwd->pw_shell, sizeof(shell)); 277 strlcat(username, pwd->pw_name, sizeof(username)); 278 strlcat(logname, pwd->pw_name, sizeof(logname)); 279 cp = strrchr(pwd->pw_shell, '/'); 280 if (cp) 281 cp++; 282 else 283 cp = pwd->pw_shell; 284 if (dolog) 285 syslog(LOG_INFO, "running command for %s: %s", user, cmdbuf); 286 execl(pwd->pw_shell, cp, "-c", cmdbuf, 0); 287 perror(pwd->pw_shell); 288 if (dolog) 289 syslog(LOG_ERR, "execl failed for %s: %m", user); 290 exit(1); 291 } 292 293 void 294 error(const char *fmt, ...) 295 { 296 char buf[BUFSIZ]; 297 va_list ap; 298 299 va_start(ap, fmt); 300 buf[0] = 1; 301 (void)vsnprintf(buf+1, sizeof(buf) - 1, fmt, ap); 302 (void)write(2, buf, strlen(buf)); 303 va_end(ap); 304 } 305 306 void 307 getstr(buf, cnt, err) 308 char *buf; 309 int cnt; 310 char *err; 311 { 312 char c; 313 314 do { 315 if (read(0, &c, 1) != 1) 316 exit(1); 317 *buf++ = c; 318 if (--cnt == 0) { 319 error("%s too long\n", err); 320 exit(1); 321 } 322 } while (c != 0); 323 } 324
Indexes created Tue Sep 23 07:09:52 GMT 2025