| 1 | /*- |
| 2 | * Copyright (c) 1983, 1990, 1993, 1994 |
| 3 | * The Regents of the University of California. All rights reserved. |
| 4 | * Copyright (c) 2002 Networks Associates Technology, Inc. |
| 5 | * All rights reserved. |
| 6 | * |
| 7 | * Portions of this software were developed for the FreeBSD Project by |
| 8 | * ThinkSec AS and NAI Labs, the Security Research Division of Network |
| 9 | * Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 |
| 10 | * ("CBOSS"), as part of the DARPA CHATS research program. |
| 11 | * |
| 12 | * Redistribution and use in source and binary forms, with or without |
| 13 | * modification, are permitted provided that the following conditions |
| 14 | * are met: |
| 15 | * 1. Redistributions of source code must retain the above copyright |
| 16 | * notice, this list of conditions and the following disclaimer. |
| 17 | * 2. Redistributions in binary form must reproduce the above copyright |
| 18 | * notice, this list of conditions and the following disclaimer in the |
| 19 | * documentation and/or other materials provided with the distribution. |
| 20 | * 3. All advertising materials mentioning features or use of this software |
| 21 | * must display the following acknowledgement: |
| 22 | * This product includes software developed by the University of |
| 23 | * California, Berkeley and its contributors. |
| 24 | * 4. Neither the name of the University nor the names of its contributors |
| 25 | * may be used to endorse or promote products derived from this software |
| 26 | * without specific prior written permission. |
| 27 | * |
| 28 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
| 29 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 30 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 31 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
| 32 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 33 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 34 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 35 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 36 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 37 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 38 | * SUCH DAMAGE. |
| 39 | * |
| 40 | * @(#)rsh.c 8.3 (Berkeley) 4/6/94 |
| 41 | * $FreeBSD: src/usr.bin/rsh/rsh.c,v 1.35 2005/05/21 09:55:07 ru Exp $ |
| 42 | * $DragonFly: src/usr.bin/rsh/rsh.c,v 1.7 2007/05/18 17:05:12 dillon Exp $ |
| 43 | */ |
| 44 | |
| 45 | #include <sys/param.h> |
| 46 | #include <sys/signal.h> |
| 47 | #include <sys/socket.h> |
| 48 | #include <sys/ioctl.h> |
| 49 | #include <sys/file.h> |
| 50 | #include <sys/time.h> |
| 51 | |
| 52 | #include <netinet/in.h> |
| 53 | #include <netdb.h> |
| 54 | |
| 55 | #include <err.h> |
| 56 | #include <errno.h> |
| 57 | #include <libutil.h> |
| 58 | #include <paths.h> |
| 59 | #include <pwd.h> |
| 60 | #include <signal.h> |
| 61 | #include <stdio.h> |
| 62 | #include <stdlib.h> |
| 63 | #include <string.h> |
| 64 | #include <unistd.h> |
| 65 | |
| 66 | /* |
| 67 | * rsh - remote shell |
| 68 | */ |
| 69 | int rfd2; |
| 70 | |
| 71 | int family = PF_UNSPEC; |
| 72 | char rlogin[] = "rlogin"; |
| 73 | |
| 74 | void connect_timeout(int); |
| 75 | char *copyargs(char * const *); |
| 76 | void sendsig(int); |
| 77 | void talk(int, long, pid_t, int, int); |
| 78 | void usage(void); |
| 79 | |
| 80 | int |
| 81 | main(int argc, char **argv) |
| 82 | { |
| 83 | struct passwd const *pw; |
| 84 | struct servent const *sp; |
| 85 | long omask; |
| 86 | int argoff, asrsh, ch, dflag, nflag, one, rem; |
| 87 | pid_t pid = 0; |
| 88 | uid_t uid; |
| 89 | char *args, *host, *p, *user; |
| 90 | int timeout = 0; |
| 91 | |
| 92 | argoff = asrsh = dflag = nflag = 0; |
| 93 | one = 1; |
| 94 | host = user = NULL; |
| 95 | |
| 96 | /* if called as something other than "rsh", use it as the host name */ |
| 97 | if ((p = strrchr(argv[0], '/'))) |
| 98 | ++p; |
| 99 | else |
| 100 | p = argv[0]; |
| 101 | if (strcmp(p, "rsh")) |
| 102 | host = p; |
| 103 | else |
| 104 | asrsh = 1; |
| 105 | |
| 106 | /* handle "rsh host flags" */ |
| 107 | if (!host && argc > 2 && argv[1][0] != '-') { |
| 108 | host = argv[1]; |
| 109 | argoff = 1; |
| 110 | } |
| 111 | |
| 112 | #define OPTIONS "468Lde:l:nt:w" |
| 113 | while ((ch = getopt(argc - argoff, argv + argoff, OPTIONS)) != -1) |
| 114 | switch(ch) { |
| 115 | case '4': |
| 116 | family = PF_INET; |
| 117 | break; |
| 118 | |
| 119 | case '6': |
| 120 | family = PF_INET6; |
| 121 | break; |
| 122 | |
| 123 | case 'L': /* -8Lew are ignored to allow rlogin aliases */ |
| 124 | case 'e': |
| 125 | case 'w': |
| 126 | case '8': |
| 127 | break; |
| 128 | case 'd': |
| 129 | dflag = 1; |
| 130 | break; |
| 131 | case 'l': |
| 132 | user = optarg; |
| 133 | break; |
| 134 | case 'n': |
| 135 | nflag = 1; |
| 136 | break; |
| 137 | case 't': |
| 138 | timeout = atoi(optarg); |
| 139 | break; |
| 140 | case '?': |
| 141 | default: |
| 142 | usage(); |
| 143 | } |
| 144 | optind += argoff; |
| 145 | |
| 146 | /* if haven't gotten a host yet, do so */ |
| 147 | if (!host && !(host = argv[optind++])) |
| 148 | usage(); |
| 149 | |
| 150 | /* if no further arguments, must have been called as rlogin. */ |
| 151 | if (!argv[optind]) { |
| 152 | if (asrsh) |
| 153 | *argv = rlogin; |
| 154 | execv(_PATH_RLOGIN, argv); |
| 155 | err(1, "can't exec %s", _PATH_RLOGIN); |
| 156 | } |
| 157 | |
| 158 | argc -= optind; |
| 159 | argv += optind; |
| 160 | |
| 161 | if (!(pw = getpwuid(uid = getuid()))) |
| 162 | errx(1, "unknown user id"); |
| 163 | if (!user) |
| 164 | user = pw->pw_name; |
| 165 | |
| 166 | args = copyargs(argv); |
| 167 | |
| 168 | sp = NULL; |
| 169 | if (sp == NULL) |
| 170 | sp = getservbyname("shell", "tcp"); |
| 171 | if (sp == NULL) |
| 172 | errx(1, "shell/tcp: unknown service"); |
| 173 | |
| 174 | if (timeout) { |
| 175 | signal(SIGALRM, connect_timeout); |
| 176 | alarm(timeout); |
| 177 | } |
| 178 | rem = rcmd_af(&host, sp->s_port, pw->pw_name, user, args, &rfd2, |
| 179 | family); |
| 180 | if (timeout) { |
| 181 | signal(SIGALRM, SIG_DFL); |
| 182 | alarm(0); |
| 183 | } |
| 184 | |
| 185 | if (rem < 0) |
| 186 | exit(1); |
| 187 | |
| 188 | if (rfd2 < 0) |
| 189 | errx(1, "can't establish stderr"); |
| 190 | if (dflag) { |
| 191 | if (setsockopt(rem, SOL_SOCKET, SO_DEBUG, &one, |
| 192 | sizeof(one)) < 0) |
| 193 | warn("setsockopt"); |
| 194 | if (setsockopt(rfd2, SOL_SOCKET, SO_DEBUG, &one, |
| 195 | sizeof(one)) < 0) |
| 196 | warn("setsockopt"); |
| 197 | } |
| 198 | |
| 199 | setuid(uid); |
| 200 | omask = sigblock(sigmask(SIGINT)|sigmask(SIGQUIT)|sigmask(SIGTERM)); |
| 201 | if (signal(SIGINT, SIG_IGN) != SIG_IGN) |
| 202 | signal(SIGINT, sendsig); |
| 203 | if (signal(SIGQUIT, SIG_IGN) != SIG_IGN) |
| 204 | signal(SIGQUIT, sendsig); |
| 205 | if (signal(SIGTERM, SIG_IGN) != SIG_IGN) |
| 206 | signal(SIGTERM, sendsig); |
| 207 | |
| 208 | if (!nflag) { |
| 209 | pid = fork(); |
| 210 | if (pid < 0) |
| 211 | err(1, "fork"); |
| 212 | } |
| 213 | else |
| 214 | shutdown(rem, SHUT_WR); |
| 215 | |
| 216 | ioctl(rfd2, FIONBIO, &one); |
| 217 | ioctl(rem, FIONBIO, &one); |
| 218 | |
| 219 | talk(nflag, omask, pid, rem, timeout); |
| 220 | |
| 221 | if (!nflag) |
| 222 | kill(pid, SIGKILL); |
| 223 | exit(0); |
| 224 | } |
| 225 | |
| 226 | void |
| 227 | talk(int nflag, long omask, pid_t pid, int rem, int timeout) |
| 228 | { |
| 229 | int cc, wc; |
| 230 | fd_set readfrom, ready, rembits; |
| 231 | char buf[BUFSIZ]; |
| 232 | const char *bp; |
| 233 | struct timeval tvtimeout; |
| 234 | int nfds, srval; |
| 235 | |
| 236 | if (!nflag && pid == 0) { |
| 237 | close(rfd2); |
| 238 | |
| 239 | reread: errno = 0; |
| 240 | if ((cc = read(STDIN_FILENO, buf, sizeof(buf))) <= 0) |
| 241 | goto done; |
| 242 | bp = buf; |
| 243 | |
| 244 | rewrite: |
| 245 | if (rem >= FD_SETSIZE) |
| 246 | errx(1, "descriptor too big"); |
| 247 | FD_ZERO(&rembits); |
| 248 | FD_SET(rem, &rembits); |
| 249 | nfds = rem + 1; |
| 250 | if (select(nfds, 0, &rembits, 0, 0) < 0) { |
| 251 | if (errno != EINTR) |
| 252 | err(1, "select"); |
| 253 | goto rewrite; |
| 254 | } |
| 255 | if (!FD_ISSET(rem, &rembits)) |
| 256 | goto rewrite; |
| 257 | wc = write(rem, bp, cc); |
| 258 | if (wc < 0) { |
| 259 | if (errno == EWOULDBLOCK) |
| 260 | goto rewrite; |
| 261 | goto done; |
| 262 | } |
| 263 | bp += wc; |
| 264 | cc -= wc; |
| 265 | if (cc == 0) |
| 266 | goto reread; |
| 267 | goto rewrite; |
| 268 | done: |
| 269 | shutdown(rem, SHUT_WR); |
| 270 | exit(0); |
| 271 | } |
| 272 | |
| 273 | tvtimeout.tv_sec = timeout; |
| 274 | tvtimeout.tv_usec = 0; |
| 275 | |
| 276 | sigsetmask(omask); |
| 277 | if (rfd2 >= FD_SETSIZE || rem >= FD_SETSIZE) |
| 278 | errx(1, "descriptor too big"); |
| 279 | FD_ZERO(&readfrom); |
| 280 | FD_SET(rfd2, &readfrom); |
| 281 | FD_SET(rem, &readfrom); |
| 282 | nfds = MAX(rfd2+1, rem+1); |
| 283 | do { |
| 284 | ready = readfrom; |
| 285 | if (timeout) { |
| 286 | srval = select(nfds, &ready, 0, 0, &tvtimeout); |
| 287 | } else { |
| 288 | srval = select(nfds, &ready, 0, 0, 0); |
| 289 | } |
| 290 | |
| 291 | if (srval < 0) { |
| 292 | if (errno != EINTR) |
| 293 | err(1, "select"); |
| 294 | continue; |
| 295 | } |
| 296 | if (srval == 0) |
| 297 | errx(1, "timeout reached (%d seconds)", timeout); |
| 298 | if (FD_ISSET(rfd2, &ready)) { |
| 299 | errno = 0; |
| 300 | cc = read(rfd2, buf, sizeof(buf)); |
| 301 | if (cc <= 0) { |
| 302 | if (errno != EWOULDBLOCK) |
| 303 | FD_CLR(rfd2, &readfrom); |
| 304 | } else |
| 305 | write(STDERR_FILENO, buf, cc); |
| 306 | } |
| 307 | if (FD_ISSET(rem, &ready)) { |
| 308 | errno = 0; |
| 309 | cc = read(rem, buf, sizeof(buf)); |
| 310 | if (cc <= 0) { |
| 311 | if (errno != EWOULDBLOCK) |
| 312 | FD_CLR(rem, &readfrom); |
| 313 | } else |
| 314 | write(STDOUT_FILENO, buf, cc); |
| 315 | } |
| 316 | } while (FD_ISSET(rfd2, &readfrom) || FD_ISSET(rem, &readfrom)); |
| 317 | } |
| 318 | |
| 319 | void |
| 320 | connect_timeout(int sig __unused) |
| 321 | { |
| 322 | char message[] = "timeout reached before connection completed.\n"; |
| 323 | |
| 324 | write(STDERR_FILENO, message, sizeof(message) - 1); |
| 325 | _exit(1); |
| 326 | } |
| 327 | |
| 328 | void |
| 329 | sendsig(int sig) |
| 330 | { |
| 331 | char signo; |
| 332 | |
| 333 | signo = sig; |
| 334 | write(rfd2, &signo, 1); |
| 335 | } |
| 336 | |
| 337 | char * |
| 338 | copyargs(char * const *argv) |
| 339 | { |
| 340 | int cc; |
| 341 | char *args, *p; |
| 342 | char * const *ap; |
| 343 | |
| 344 | cc = 0; |
| 345 | for (ap = argv; *ap; ++ap) |
| 346 | cc += strlen(*ap) + 1; |
| 347 | if (!(args = malloc((u_int)cc))) |
| 348 | err(1, NULL); |
| 349 | for (p = args, ap = argv; *ap; ++ap) { |
| 350 | strcpy(p, *ap); |
| 351 | for (p = strcpy(p, *ap); *p; ++p); |
| 352 | if (ap[1]) |
| 353 | *p++ = ' '; |
| 354 | } |
| 355 | return (args); |
| 356 | } |
| 357 | |
| 358 | void |
| 359 | usage(void) |
| 360 | { |
| 361 | |
| 362 | fprintf(stderr, |
| 363 | "usage: rsh [-46dn] [-l username] [-t timeout] host [command]\n"); |
| 364 | exit(1); |
| 365 | } |