builtins.c revision 49004
1/*- 2 * Copyright (c) 1983, 1991, 1993, 1994 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 * 26 * $Id$ 27 * 28 */ 29 30#include <sys/filio.h> 31#include <sys/ioccom.h> 32#include <sys/param.h> 33#include <sys/stat.h> 34#include <sys/socket.h> 35#include <sys/sysctl.h> 36#include <sys/ucred.h> 37#include <sys/uio.h> 38#include <sys/utsname.h> 39 40#include <ctype.h> 41#include <err.h> 42#include <errno.h> 43#include <limits.h> 44#include <pwd.h> 45#include <signal.h> 46#include <stdlib.h> 47#include <string.h> 48#include <unistd.h> 49 50#include "inetd.h" 51 52extern int debug; 53extern struct servtab *servtab; 54 55char ring[128]; 56char *endring; 57 58int check_loop __P((struct sockaddr_in *, struct servtab *sep)); 59void inetd_setproctitle __P((char *, int)); 60 61struct biltin biltins[] = { 62 /* Echo received data */ 63 { "echo", SOCK_STREAM, 1, -1, echo_stream }, 64 { "echo", SOCK_DGRAM, 0, 1, echo_dg }, 65 66 /* Internet /dev/null */ 67 { "discard", SOCK_STREAM, 1, -1, discard_stream }, 68 { "discard", SOCK_DGRAM, 0, 1, discard_dg }, 69 70 /* Return 32 bit time since 1970 */ 71 { "time", SOCK_STREAM, 0, -1, machtime_stream }, 72 { "time", SOCK_DGRAM, 0, 1, machtime_dg }, 73 74 /* Return human-readable time */ 75 { "daytime", SOCK_STREAM, 0, -1, daytime_stream }, 76 { "daytime", SOCK_DGRAM, 0, 1, daytime_dg }, 77 78 /* Familiar character generator */ 79 { "chargen", SOCK_STREAM, 1, -1, chargen_stream }, 80 { "chargen", SOCK_DGRAM, 0, 1, chargen_dg }, 81 82 { "tcpmux", SOCK_STREAM, 1, -1, (void (*)())tcpmux }, 83 84 { "auth", SOCK_STREAM, 1, -1, ident_stream }, 85 86 { NULL } 87}; 88 89void 90initring() 91{ 92 int i; 93 94 endring = ring; 95 96 for (i = 0; i <= 128; ++i) 97 if (isprint(i)) 98 *endring++ = i; 99} 100 101/* ARGSUSED */ 102void 103chargen_dg(s, sep) /* Character generator */ 104 int s; 105 struct servtab *sep; 106{ 107 struct sockaddr_in sin; 108 static char *rs; 109 int len, size; 110 char text[LINESIZ+2]; 111 112 if (endring == 0) { 113 initring(); 114 rs = ring; 115 } 116 117 size = sizeof(sin); 118 if (recvfrom(s, text, sizeof(text), 0, 119 (struct sockaddr *)&sin, &size) < 0) 120 return; 121 122 if (check_loop(&sin, sep)) 123 return; 124 125 if ((len = endring - rs) >= LINESIZ) 126 memmove(text, rs, LINESIZ); 127 else { 128 memmove(text, rs, len); 129 memmove(text + len, ring, LINESIZ - len); 130 } 131 if (++rs == endring) 132 rs = ring; 133 text[LINESIZ] = '\r'; 134 text[LINESIZ + 1] = '\n'; 135 (void) sendto(s, text, sizeof(text), 0, 136 (struct sockaddr *)&sin, sizeof(sin)); 137} 138 139/* ARGSUSED */ 140void 141chargen_stream(s, sep) /* Character generator */ 142 int s; 143 struct servtab *sep; 144{ 145 int len; 146 char *rs, text[LINESIZ+2]; 147 148 inetd_setproctitle(sep->se_service, s); 149 150 if (!endring) { 151 initring(); 152 rs = ring; 153 } 154 155 text[LINESIZ] = '\r'; 156 text[LINESIZ + 1] = '\n'; 157 for (rs = ring;;) { 158 if ((len = endring - rs) >= LINESIZ) 159 memmove(text, rs, LINESIZ); 160 else { 161 memmove(text, rs, len); 162 memmove(text + len, ring, LINESIZ - len); 163 } 164 if (++rs == endring) 165 rs = ring; 166 if (write(s, text, sizeof(text)) != sizeof(text)) 167 break; 168 } 169 exit(0); 170} 171 172/* ARGSUSED */ 173void 174daytime_dg(s, sep) /* Return human-readable time of day */ 175 int s; 176 struct servtab *sep; 177{ 178 char buffer[256]; 179 time_t clock; 180 struct sockaddr_in sin; 181 int size; 182 183 clock = time((time_t *) 0); 184 185 size = sizeof(sin); 186 if (recvfrom(s, buffer, sizeof(buffer), 0, 187 (struct sockaddr *)&sin, &size) < 0) 188 return; 189 190 if (check_loop(&sin, sep)) 191 return; 192 193 (void) sprintf(buffer, "%.24s\r\n", ctime(&clock)); 194 (void) sendto(s, buffer, strlen(buffer), 0, 195 (struct sockaddr *)&sin, sizeof(sin)); 196} 197 198/* ARGSUSED */ 199void 200daytime_stream(s, sep) /* Return human-readable time of day */ 201 int s; 202 struct servtab *sep; 203{ 204 char buffer[256]; 205 time_t clock; 206 207 clock = time((time_t *) 0); 208 209 (void) sprintf(buffer, "%.24s\r\n", ctime(&clock)); 210 (void) write(s, buffer, strlen(buffer)); 211} 212 213/* ARGSUSED */ 214void 215discard_dg(s, sep) /* Discard service -- ignore data */ 216 int s; 217 struct servtab *sep; 218{ 219 char buffer[BUFSIZE]; 220 221 (void) read(s, buffer, sizeof(buffer)); 222} 223 224/* ARGSUSED */ 225void 226discard_stream(s, sep) /* Discard service -- ignore data */ 227 int s; 228 struct servtab *sep; 229{ 230 int ret; 231 char buffer[BUFSIZE]; 232 233 inetd_setproctitle(sep->se_service, s); 234 while (1) { 235 while ((ret = read(s, buffer, sizeof(buffer))) > 0) 236 ; 237 if (ret == 0 || errno != EINTR) 238 break; 239 } 240 exit(0); 241} 242 243/* ARGSUSED */ 244void 245echo_dg(s, sep) /* Echo service -- echo data back */ 246 int s; 247 struct servtab *sep; 248{ 249 char buffer[BUFSIZE]; 250 int i, size; 251 struct sockaddr_in sin; 252 253 size = sizeof(sin); 254 if ((i = recvfrom(s, buffer, sizeof(buffer), 0, 255 (struct sockaddr *)&sin, &size)) < 0) 256 return; 257 258 if (check_loop(&sin, sep)) 259 return; 260 261 (void) sendto(s, buffer, i, 0, (struct sockaddr *)&sin, 262 sizeof(sin)); 263} 264 265/* ARGSUSED */ 266void 267echo_stream(s, sep) /* Echo service -- echo data back */ 268 int s; 269 struct servtab *sep; 270{ 271 char buffer[BUFSIZE]; 272 int i; 273 274 inetd_setproctitle(sep->se_service, s); 275 while ((i = read(s, buffer, sizeof(buffer))) > 0 && 276 write(s, buffer, i) > 0) 277 ; 278 exit(0); 279} 280 281/* ARGSUSED */ 282void 283iderror(lport, fport, s, er) 284 int lport, fport, s, er; 285{ 286 char *p; 287 288 er = asprintf(&p, "%d , %d : ERROR : %s\r\n", lport, fport, 289 er == -1 ? "HIDDEN-USER" : er ? strerror(er) : "UNKNOWN-ERROR"); 290 if (er == -1) 291 exit(0); 292 write(s, p, strlen(p)); 293 free(p); 294 295 exit(0); 296} 297 298/* ARGSUSED */ 299void 300ident_stream(s, sep) /* Ident service */ 301 int s; 302 struct servtab *sep; 303{ 304 struct sockaddr_in sin[2]; 305 struct ucred uc; 306 struct passwd *pw; 307 struct timeval tv = { 308 10, 309 0 310 }; 311 fd_set fdset; 312 char buf[BUFSIZE], *cp = NULL, *p, **av, *osname = NULL; 313 int len, c, rflag = 0, fflag = 0, argc = 0; 314 u_short lport, fport; 315 316 inetd_setproctitle(sep->se_service, s); 317 optind = 1; 318 optreset = 1; 319 for (av = sep->se_argv; *av; av++) 320 argc++; 321 if (argc) { 322 while ((c = getopt(argc, sep->se_argv, "fro:")) != -1) 323 switch (c) { 324 case 'f': 325 fflag = 1; 326 break; 327 case 'r': 328 rflag = 1; 329 break; 330 case 'o': 331 osname = optarg; 332 break; 333 default: 334 break; 335 } 336 } 337 if (osname == NULL) { 338 struct utsname un; 339 340 if (uname(&un)) 341 iderror(0, 0, s, errno); 342 osname = un.sysname; 343 } 344 len = sizeof(sin[0]); 345 if (getsockname(s, (struct sockaddr *)&sin[0], &len) == -1) 346 iderror(0, 0, s, errno); 347 len = sizeof(sin[1]); 348 if (getpeername(s, (struct sockaddr *)&sin[1], &len) == -1) 349 iderror(0, 0, s, errno); 350 FD_ZERO(&fdset); 351 FD_SET(s, &fdset); 352 if (select(s + 1, &fdset, NULL, NULL, &tv) == -1) 353 iderror(0, 0, s, errno); 354 if (ioctl(s, FIONREAD, &len) == -1) 355 iderror(0, 0, s, errno); 356 if (len >= sizeof(buf)) 357 len = sizeof(buf) - 1; 358 len = read(s, buf, len); 359 if (len == -1) 360 iderror(0, 0, s, errno); 361 buf[len] = '\0'; 362 if (sscanf(buf, "%hu,%hu", &lport, &fport) != 2) 363 iderror(0, 0, s, 0); 364 if (!rflag) 365 iderror(lport, fport, s, -1); 366 sin[0].sin_port = htons(lport); 367 sin[1].sin_port = htons(fport); 368 len = sizeof(uc); 369 if (sysctlbyname("net.inet.tcp.getcred", &uc, &len, sin, 370 sizeof(sin)) == -1) 371 iderror(lport, fport, s, errno); 372 pw = getpwuid(uc.cr_uid); 373 if (pw == NULL) 374 iderror(lport, fport, s, errno); 375 if (fflag) { 376 FILE *fakeid = NULL; 377 char fakeid_path[PATH_MAX]; 378 struct stat sb; 379 seteuid(pw->pw_uid); 380 setegid(pw->pw_gid); 381 snprintf(fakeid_path, sizeof(fakeid_path), "%s/.fakeid", 382 pw->pw_dir); 383 if ((fakeid = fopen(fakeid_path, "r")) != NULL && 384 fstat(fileno(fakeid), &sb) != -1 && S_ISREG(sb.st_mode)) { 385 buf[sizeof(buf) - 1] = '\0'; 386 if (fgets(buf, sizeof(buf), fakeid) == NULL) { 387 cp = pw->pw_name; 388 fclose(fakeid); 389 goto printit; 390 } 391 fclose(fakeid); 392 strtok(buf, "\r\n"); 393 if (strlen(buf) > 16) 394 buf[16] = '\0'; 395 cp = buf; 396 while (isspace(*cp)) 397 cp++; 398 strtok(cp, " \t"); 399 if (!*cp || getpwnam(cp)) 400 cp = getpwuid(uc.cr_uid)->pw_name; 401 } else 402 cp = pw->pw_name; 403 } else 404 cp = pw->pw_name; 405printit: 406 if (asprintf(&p, "%d , %d : USERID : %s : %s\r\n", lport, fport, osname, 407 cp) == -1) 408 iderror(0, 0, s, errno); 409 write(s, p, strlen(p)); 410 free(p); 411 412 exit(0); 413} 414 415/* 416 * Return a machine readable date and time, in the form of the 417 * number of seconds since midnight, Jan 1, 1900. Since gettimeofday 418 * returns the number of seconds since midnight, Jan 1, 1970, 419 * we must add 2208988800 seconds to this figure to make up for 420 * some seventy years Bell Labs was asleep. 421 */ 422 423unsigned long 424machtime() 425{ 426 struct timeval tv; 427 428 if (gettimeofday(&tv, (struct timezone *)NULL) < 0) { 429 if (debug) 430 warnx("unable to get time of day"); 431 return (0L); 432 } 433#define OFFSET ((u_long)25567 * 24*60*60) 434 return (htonl((long)(tv.tv_sec + OFFSET))); 435#undef OFFSET 436} 437 438/* ARGSUSED */ 439void 440machtime_dg(s, sep) 441 int s; 442 struct servtab *sep; 443{ 444 unsigned long result; 445 struct sockaddr_in sin; 446 int size; 447 448 size = sizeof(sin); 449 if (recvfrom(s, (char *)&result, sizeof(result), 0, 450 (struct sockaddr *)&sin, &size) < 0) 451 return; 452 453 if (check_loop(&sin, sep)) 454 return; 455 456 result = machtime(); 457 (void) sendto(s, (char *) &result, sizeof(result), 0, 458 (struct sockaddr *)&sin, sizeof(sin)); 459} 460 461/* ARGSUSED */ 462void 463machtime_stream(s, sep) 464 int s; 465 struct servtab *sep; 466{ 467 unsigned long result; 468 469 result = machtime(); 470 (void) write(s, (char *) &result, sizeof(result)); 471} 472 473/* 474 * Based on TCPMUX.C by Mark K. Lottor November 1988 475 * sri-nic::ps:<mkl>tcpmux.c 476 */ 477 478#define MAX_SERV_LEN (256+2) /* 2 bytes for \r\n */ 479#define strwrite(fd, buf) (void) write(fd, buf, sizeof(buf)-1) 480 481static int /* # of characters upto \r,\n or \0 */ 482getline(fd, buf, len) 483 int fd; 484 char *buf; 485 int len; 486{ 487 int count = 0, n; 488 struct sigaction sa; 489 490 sa.sa_flags = 0; 491 sigemptyset(&sa.sa_mask); 492 sa.sa_handler = SIG_DFL; 493 sigaction(SIGALRM, &sa, (struct sigaction *)0); 494 do { 495 alarm(10); 496 n = read(fd, buf, len-count); 497 alarm(0); 498 if (n == 0) 499 return (count); 500 if (n < 0) 501 return (-1); 502 while (--n >= 0) { 503 if (*buf == '\r' || *buf == '\n' || *buf == '\0') 504 return (count); 505 count++; 506 buf++; 507 } 508 } while (count < len); 509 return (count); 510} 511 512struct servtab * 513tcpmux(s) 514 int s; 515{ 516 struct servtab *sep; 517 char service[MAX_SERV_LEN+1]; 518 int len; 519 520 /* Get requested service name */ 521 if ((len = getline(s, service, MAX_SERV_LEN)) < 0) { 522 strwrite(s, "-Error reading service name\r\n"); 523 return (NULL); 524 } 525 service[len] = '\0'; 526 527 if (debug) 528 warnx("tcpmux: someone wants %s", service); 529 530 /* 531 * Help is a required command, and lists available services, 532 * one per line. 533 */ 534 if (!strcasecmp(service, "help")) { 535 for (sep = servtab; sep; sep = sep->se_next) { 536 if (!ISMUX(sep)) 537 continue; 538 (void)write(s,sep->se_service,strlen(sep->se_service)); 539 strwrite(s, "\r\n"); 540 } 541 return (NULL); 542 } 543 544 /* Try matching a service in inetd.conf with the request */ 545 for (sep = servtab; sep; sep = sep->se_next) { 546 if (!ISMUX(sep)) 547 continue; 548 if (!strcasecmp(service, sep->se_service)) { 549 if (ISMUXPLUS(sep)) { 550 strwrite(s, "+Go\r\n"); 551 } 552 return (sep); 553 } 554 } 555 strwrite(s, "-Service not available\r\n"); 556 return (NULL); 557} 558 559