builtins.c revision 326761
1159979Sglebius/*- 2159979Sglebius * Copyright (c) 1983, 1991, 1993, 1994 3159979Sglebius * The Regents of the University of California. All rights reserved. 4159979Sglebius * 5159979Sglebius * Redistribution and use in source and binary forms, with or without 6159979Sglebius * modification, are permitted provided that the following conditions 7159979Sglebius * are met: 8159979Sglebius * 1. Redistributions of source code must retain the above copyright 9159979Sglebius * notice, this list of conditions and the following disclaimer. 10159979Sglebius * 2. Redistributions in binary form must reproduce the above copyright 11159979Sglebius * notice, this list of conditions and the following disclaimer in the 12159979Sglebius * documentation and/or other materials provided with the distribution. 13159979Sglebius * 14159979Sglebius * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15159979Sglebius * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16159979Sglebius * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17159979Sglebius * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18159979Sglebius * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19159979Sglebius * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20159979Sglebius * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21159979Sglebius * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22159979Sglebius * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23159979Sglebius * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24159979Sglebius * SUCH DAMAGE. 25159979Sglebius */ 26159979Sglebius 27159979Sglebius#include <sys/cdefs.h> 28160050Sru__FBSDID("$FreeBSD: stable/10/usr.sbin/inetd/builtins.c 326761 2017-12-11 05:10:11Z delphij $"); 29159979Sglebius 30159979Sglebius#include <sys/filio.h> 31159979Sglebius#include <sys/ioccom.h> 32159979Sglebius#include <sys/param.h> 33159979Sglebius#include <sys/stat.h> 34159979Sglebius#include <sys/socket.h> 35159979Sglebius#include <sys/sysctl.h> 36159979Sglebius#include <sys/ucred.h> 37159979Sglebius#include <sys/uio.h> 38159979Sglebius#include <sys/utsname.h> 39159979Sglebius 40159979Sglebius#include <ctype.h> 41159979Sglebius#include <err.h> 42159979Sglebius#include <errno.h> 43159979Sglebius#include <fcntl.h> 44159979Sglebius#include <limits.h> 45159979Sglebius#include <pwd.h> 46159979Sglebius#include <signal.h> 47159979Sglebius#include <stdlib.h> 48159979Sglebius#include <string.h> 49159979Sglebius#include <sysexits.h> 50159979Sglebius#include <syslog.h> 51159979Sglebius#include <unistd.h> 52159979Sglebius 53159979Sglebius#include "inetd.h" 54159979Sglebius 55159979Sglebiusvoid chargen_dg(int, struct servtab *); 56159979Sglebiusvoid chargen_stream(int, struct servtab *); 57159979Sglebiusvoid daytime_dg(int, struct servtab *); 58159979Sglebiusvoid daytime_stream(int, struct servtab *); 59159979Sglebiusvoid discard_dg(int, struct servtab *); 60159979Sglebiusvoid discard_stream(int, struct servtab *); 61159979Sglebiusvoid echo_dg(int, struct servtab *); 62159979Sglebiusvoid echo_stream(int, struct servtab *); 63159979Sglebiusstatic int getline(int, char *, int); 64159979Sglebiusvoid iderror(int, int, int, const char *); 65159979Sglebiusvoid ident_stream(int, struct servtab *); 66159979Sglebiusvoid initring(void); 67159979Sglebiusuint32_t machtime(void); 68159979Sglebiusvoid machtime_dg(int, struct servtab *); 69159979Sglebiusvoid machtime_stream(int, struct servtab *); 70159979Sglebius 71159979Sglebiuschar ring[128]; 72159979Sglebiuschar *endring; 73159979Sglebius 74159979Sglebius 75159979Sglebiusstruct biltin biltins[] = { 76159979Sglebius /* Echo received data */ 77159979Sglebius { "echo", SOCK_STREAM, 1, -1, echo_stream }, 78159979Sglebius { "echo", SOCK_DGRAM, 0, 1, echo_dg }, 79159979Sglebius 80159979Sglebius /* Internet /dev/null */ 81159979Sglebius { "discard", SOCK_STREAM, 1, -1, discard_stream }, 82159979Sglebius { "discard", SOCK_DGRAM, 0, 1, discard_dg }, 83159979Sglebius 84159979Sglebius /* Return 32 bit time since 1900 */ 85159979Sglebius { "time", SOCK_STREAM, 0, -1, machtime_stream }, 86159979Sglebius { "time", SOCK_DGRAM, 0, 1, machtime_dg }, 87159979Sglebius 88159979Sglebius /* Return human-readable time */ 89159979Sglebius { "daytime", SOCK_STREAM, 0, -1, daytime_stream }, 90159979Sglebius { "daytime", SOCK_DGRAM, 0, 1, daytime_dg }, 91159979Sglebius 92159979Sglebius /* Familiar character generator */ 93159979Sglebius { "chargen", SOCK_STREAM, 1, -1, chargen_stream }, 94159979Sglebius { "chargen", SOCK_DGRAM, 0, 1, chargen_dg }, 95159979Sglebius 96159979Sglebius { "tcpmux", SOCK_STREAM, 1, -1, (bi_fn_t *)tcpmux }, 97159979Sglebius 98159979Sglebius { "auth", SOCK_STREAM, 1, -1, ident_stream }, 99159979Sglebius 100159979Sglebius { NULL, 0, 0, 0, NULL } 101159979Sglebius}; 102159979Sglebius 103159979Sglebius/* 104159979Sglebius * RFC864 Character Generator Protocol. Generates character data without 105159979Sglebius * any regard for input. 106159979Sglebius */ 107159979Sglebius 108159979Sglebiusvoid 109159979Sglebiusinitring(void) 110159979Sglebius{ 111159979Sglebius int i; 112159979Sglebius 113159979Sglebius endring = ring; 114159979Sglebius 115242997Sjoel for (i = 0; i <= 128; ++i) 116242997Sjoel if (isprint(i)) 117159979Sglebius *endring++ = i; 118159979Sglebius} 119159979Sglebius 120159979Sglebius/* Character generator 121159979Sglebius * The RFC says that we should send back a random number of 122159979Sglebius * characters chosen from the range 0 to 512. We send LINESIZ+2. 123159979Sglebius */ 124159979Sglebius/* ARGSUSED */ 125159979Sglebiusvoid 126159979Sglebiuschargen_dg(int s, struct servtab *sep) 127159979Sglebius{ 128159979Sglebius struct sockaddr_storage ss; 129159979Sglebius static char *rs; 130159979Sglebius int len; 131159979Sglebius socklen_t size; 132159979Sglebius char text[LINESIZ+2]; 133159979Sglebius 134159979Sglebius if (endring == 0) { 135159979Sglebius initring(); 136159979Sglebius rs = ring; 137159979Sglebius } 138159979Sglebius 139159979Sglebius size = sizeof(ss); 140159979Sglebius if (recvfrom(s, text, sizeof(text), 0, 141159979Sglebius (struct sockaddr *)&ss, &size) < 0) 142159979Sglebius return; 143159979Sglebius 144159979Sglebius if (check_loop((struct sockaddr *)&ss, sep)) 145159979Sglebius return; 146159979Sglebius 147159979Sglebius if ((len = endring - rs) >= LINESIZ) 148159979Sglebius memmove(text, rs, LINESIZ); 149159979Sglebius else { 150159979Sglebius memmove(text, rs, len); 151159979Sglebius memmove(text + len, ring, LINESIZ - len); 152242997Sjoel } 153159979Sglebius if (++rs == endring) 154159979Sglebius rs = ring; 155159979Sglebius text[LINESIZ] = '\r'; 156159979Sglebius text[LINESIZ + 1] = '\n'; 157159979Sglebius (void) sendto(s, text, sizeof(text), 0, (struct sockaddr *)&ss, size); 158159979Sglebius} 159242997Sjoel 160159979Sglebius/* Character generator */ 161159979Sglebius/* ARGSUSED */ 162159979Sglebiusvoid 163159979Sglebiuschargen_stream(int s, struct servtab *sep) 164159979Sglebius{ 165159979Sglebius int len; 166159979Sglebius char *rs, text[LINESIZ+2]; 167159979Sglebius 168159979Sglebius inetd_setproctitle(sep->se_service, s); 169159979Sglebius 170159979Sglebius if (!endring) 171159979Sglebius initring(); 172159979Sglebius 173159979Sglebius text[LINESIZ] = '\r'; 174159979Sglebius text[LINESIZ + 1] = '\n'; 175159979Sglebius for (rs = ring;;) { 176159979Sglebius if ((len = endring - rs) >= LINESIZ) 177159979Sglebius memmove(text, rs, LINESIZ); 178242997Sjoel else { 179159979Sglebius memmove(text, rs, len); 180159979Sglebius memmove(text + len, ring, LINESIZ - len); 181159979Sglebius } 182159979Sglebius if (++rs == endring) 183159979Sglebius rs = ring; 184159979Sglebius if (write(s, text, sizeof(text)) != sizeof(text)) 185242997Sjoel break; 186159979Sglebius } 187159979Sglebius exit(0); 188159979Sglebius} 189159979Sglebius 190159979Sglebius/* 191242997Sjoel * RFC867 Daytime Protocol. Sends the current date and time as an ascii 192159979Sglebius * character string without any regard for input. 193159979Sglebius */ 194159979Sglebius 195159979Sglebius/* Return human-readable time of day */ 196242997Sjoel/* ARGSUSED */ 197159979Sglebiusvoid 198159979Sglebiusdaytime_dg(int s, struct servtab *sep) 199159979Sglebius{ 200159979Sglebius char buffer[256]; 201159979Sglebius time_t now; 202159979Sglebius struct sockaddr_storage ss; 203159979Sglebius socklen_t size; 204159979Sglebius 205159979Sglebius now = time((time_t *) 0); 206159979Sglebius 207159979Sglebius size = sizeof(ss); 208159979Sglebius if (recvfrom(s, buffer, sizeof(buffer), 0, 209159979Sglebius (struct sockaddr *)&ss, &size) < 0) 210165216Smpp return; 211159979Sglebius 212159979Sglebius if (check_loop((struct sockaddr *)&ss, sep)) 213159979Sglebius return; 214159979Sglebius 215159979Sglebius (void) sprintf(buffer, "%.24s\r\n", ctime(&now)); 216159979Sglebius (void) sendto(s, buffer, strlen(buffer), 0, 217159979Sglebius (struct sockaddr *)&ss, size); 218159979Sglebius} 219159979Sglebius 220159979Sglebius/* Return human-readable time of day */ 221160050Sru/* ARGSUSED */ 222159979Sglebiusvoid 223159979Sglebiusdaytime_stream(int s, struct servtab *sep __unused) 224159979Sglebius{ 225160050Sru char buffer[256]; 226159979Sglebius time_t now; 227160050Sru 228159979Sglebius now = time((time_t *) 0); 229159979Sglebius 230159979Sglebius (void) sprintf(buffer, "%.24s\r\n", ctime(&now)); 231159979Sglebius (void) send(s, buffer, strlen(buffer), MSG_EOF); 232159979Sglebius} 233159979Sglebius 234159979Sglebius/* 235159979Sglebius * RFC863 Discard Protocol. Any data received is thrown away and no response 236159979Sglebius * is sent. 237159979Sglebius */ 238160050Sru 239159979Sglebius/* Discard service -- ignore data */ 240160050Sru/* ARGSUSED */ 241159979Sglebiusvoid 242159979Sglebiusdiscard_dg(int s, struct servtab *sep __unused) 243159979Sglebius{ 244159979Sglebius char buffer[BUFSIZE]; 245159979Sglebius 246160050Sru (void) read(s, buffer, sizeof(buffer)); 247159979Sglebius} 248160050Sru 249159979Sglebius/* Discard service -- ignore data */ 250159979Sglebius/* ARGSUSED */ 251159979Sglebiusvoid 252159979Sglebiusdiscard_stream(int s, struct servtab *sep) 253159979Sglebius{ 254159979Sglebius int ret; 255159979Sglebius char buffer[BUFSIZE]; 256159979Sglebius 257159979Sglebius inetd_setproctitle(sep->se_service, s); 258159979Sglebius while (1) { 259159979Sglebius while ((ret = read(s, buffer, sizeof(buffer))) > 0) 260159979Sglebius ; 261159979Sglebius if (ret == 0 || errno != EINTR) 262159979Sglebius break; 263159979Sglebius } 264159979Sglebius exit(0); 265159979Sglebius} 266159979Sglebius 267159979Sglebius/* 268159979Sglebius * RFC862 Echo Protocol. Any data received is sent back to the sender as 269159979Sglebius * received. 270159979Sglebius */ 271159979Sglebius 272159979Sglebius/* Echo service -- echo data back */ 273159979Sglebius/* ARGSUSED */ 274159979Sglebiusvoid 275159979Sglebiusecho_dg(int s, struct servtab *sep) 276159979Sglebius{ 277159979Sglebius char buffer[65536]; /* Should be sizeof(max datagram). */ 278159979Sglebius int i; 279159979Sglebius socklen_t size; 280159979Sglebius struct sockaddr_storage ss; 281159979Sglebius 282159979Sglebius size = sizeof(ss); 283159979Sglebius if ((i = recvfrom(s, buffer, sizeof(buffer), 0, 284159979Sglebius (struct sockaddr *)&ss, &size)) < 0) 285159979Sglebius return; 286159979Sglebius 287249373Sjoel if (check_loop((struct sockaddr *)&ss, sep)) 288159979Sglebius return; 289159979Sglebius 290159979Sglebius (void) sendto(s, buffer, i, 0, (struct sockaddr *)&ss, size); 291159979Sglebius} 292159979Sglebius 293159979Sglebius/* Echo service -- echo data back */ 294159979Sglebius/* ARGSUSED */ 295159979Sglebiusvoid 296159979Sglebiusecho_stream(int s, struct servtab *sep) 297159979Sglebius{ 298159979Sglebius char buffer[BUFSIZE]; 299159979Sglebius int i; 300159979Sglebius 301159979Sglebius inetd_setproctitle(sep->se_service, s); 302160050Sru while ((i = read(s, buffer, sizeof(buffer))) > 0 && 303159979Sglebius write(s, buffer, i) > 0) 304160050Sru ; 305159979Sglebius exit(0); 306159979Sglebius} 307159979Sglebius 308159979Sglebius/* 309159979Sglebius * RFC1413 Identification Protocol. Given a TCP port number pair, return a 310160050Sru * character string which identifies the owner of that connection on the 311159979Sglebius * server's system. Extended to allow for ~/.fakeid support and ~/.noident 312159979Sglebius * support. 313159979Sglebius */ 314159979Sglebius 315159979Sglebius/* RFC 1413 says the following are the only errors you can return. */ 316159979Sglebius#define ID_INVALID "INVALID-PORT" /* Port number improperly specified. */ 317159979Sglebius#define ID_NOUSER "NO-USER" /* Port not in use/not identifable. */ 318159979Sglebius#define ID_HIDDEN "HIDDEN-USER" /* Hiden at user's request. */ 319159979Sglebius#define ID_UNKNOWN "UNKNOWN-ERROR" /* Everything else. */ 320159979Sglebius 321159979Sglebius/* Generic ident_stream error-sending func */ 322159979Sglebius/* ARGSUSED */ 323159979Sglebiusvoid 324159979Sglebiusiderror(int lport, int fport, int s, const char *er) 325159979Sglebius{ 326162871Sru char *p; 327162871Sru 328162871Sru asprintf(&p, "%d , %d : ERROR : %s\r\n", lport, fport, er); 329162871Sru if (p == NULL) { 330162871Sru syslog(LOG_ERR, "asprintf: %m"); 331159979Sglebius exit(EX_OSERR); 332159979Sglebius } 333162871Sru send(s, p, strlen(p), MSG_EOF); 334162871Sru free(p); 335162871Sru 336162871Sru exit(0); 337162871Sru} 338162871Sru 339/* Ident service (AKA "auth") */ 340/* ARGSUSED */ 341void 342ident_stream(int s, struct servtab *sep) 343{ 344 struct utsname un; 345 struct stat sb; 346 struct sockaddr_in sin4[2]; 347#ifdef INET6 348 struct sockaddr_in6 sin6[2]; 349#endif 350 struct sockaddr_storage ss[2]; 351 struct xucred uc; 352 struct timeval tv = { 353 10, 354 0 355 }, to; 356 struct passwd *pw = NULL; 357 fd_set fdset; 358 char buf[BUFSIZE], *p, **av, *osname = NULL, e; 359 char idbuf[MAXLOGNAME] = ""; /* Big enough to hold uid in decimal. */ 360 socklen_t socklen; 361 ssize_t ssize; 362 size_t size, bufsiz; 363 int c, fflag = 0, nflag = 0, rflag = 0, argc = 0; 364 int gflag = 0, iflag = 0, Fflag = 0, getcredfail = 0, onreadlen; 365 u_short lport, fport; 366 367 inetd_setproctitle(sep->se_service, s); 368 /* 369 * Reset getopt() since we are a fork() but not an exec() from 370 * a parent which used getopt() already. 371 */ 372 optind = 1; 373 optreset = 1; 374 /* 375 * Take the internal argument vector and count it out to make an 376 * argument count for getopt. This can be used for any internal 377 * service to read arguments and use getopt() easily. 378 */ 379 for (av = sep->se_argv; *av; av++) 380 argc++; 381 if (argc) { 382 int sec, usec; 383 size_t i; 384 u_int32_t rnd32; 385 386 while ((c = getopt(argc, sep->se_argv, "d:fFgino:rt:")) != -1) 387 switch (c) { 388 case 'd': 389 if (!gflag) 390 strlcpy(idbuf, optarg, sizeof(idbuf)); 391 break; 392 case 'f': 393 fflag = 1; 394 break; 395 case 'F': 396 fflag = 1; 397 Fflag=1; 398 break; 399 case 'g': 400 gflag = 1; 401 rnd32 = 0; /* Shush, compiler. */ 402 /* 403 * The number of bits in "rnd32" divided 404 * by the number of bits needed per iteration 405 * gives a more optimal way to reload the 406 * random number only when necessary. 407 * 408 * 32 bits from arc4random corresponds to 409 * about 6 base-36 digits, so we reseed evey 6. 410 */ 411 for (i = 0; i < sizeof(idbuf) - 1; i++) { 412 static const char *const base36 = 413 "0123456789" 414 "abcdefghijklmnopqrstuvwxyz"; 415 if (i % 6 == 0) 416 rnd32 = arc4random(); 417 idbuf[i] = base36[rnd32 % 36]; 418 rnd32 /= 36; 419 } 420 idbuf[i] = '\0'; 421 break; 422 case 'i': 423 iflag = 1; 424 break; 425 case 'n': 426 nflag = 1; 427 break; 428 case 'o': 429 osname = optarg; 430 break; 431 case 'r': 432 rflag = 1; 433 break; 434 case 't': 435 switch (sscanf(optarg, "%d.%d", &sec, &usec)) { 436 case 2: 437 tv.tv_usec = usec; 438 /* FALLTHROUGH */ 439 case 1: 440 tv.tv_sec = sec; 441 break; 442 default: 443 if (debug) 444 warnx("bad -t argument"); 445 break; 446 } 447 break; 448 default: 449 break; 450 } 451 } 452 if (osname == NULL) { 453 if (uname(&un) == -1) 454 iderror(0, 0, s, ID_UNKNOWN); 455 osname = un.sysname; 456 } 457 458 /* 459 * We're going to prepare for and execute reception of a 460 * packet of data from the user. The data is in the format 461 * "local_port , foreign_port\r\n" (with local being the 462 * server's port and foreign being the client's.) 463 */ 464 gettimeofday(&to, NULL); 465 to.tv_sec += tv.tv_sec; 466 to.tv_usec += tv.tv_usec; 467 if (to.tv_usec >= 1000000) { 468 to.tv_usec -= 1000000; 469 to.tv_sec++; 470 } 471 472 size = 0; 473 bufsiz = sizeof(buf) - 1; 474 FD_ZERO(&fdset); 475 while (bufsiz > 0) { 476 gettimeofday(&tv, NULL); 477 tv.tv_sec = to.tv_sec - tv.tv_sec; 478 tv.tv_usec = to.tv_usec - tv.tv_usec; 479 if (tv.tv_usec < 0) { 480 tv.tv_usec += 1000000; 481 tv.tv_sec--; 482 } 483 if (tv.tv_sec < 0) 484 break; 485 FD_SET(s, &fdset); 486 if (select(s + 1, &fdset, NULL, NULL, &tv) == -1) 487 iderror(0, 0, s, ID_UNKNOWN); 488 if (ioctl(s, FIONREAD, &onreadlen) == -1) 489 iderror(0, 0, s, ID_UNKNOWN); 490 if ((size_t)onreadlen > bufsiz) 491 onreadlen = bufsiz; 492 ssize = read(s, &buf[size], (size_t)onreadlen); 493 if (ssize == -1) 494 iderror(0, 0, s, ID_UNKNOWN); 495 else if (ssize == 0) 496 break; 497 bufsiz -= ssize; 498 size += ssize; 499 if (memchr(&buf[size - ssize], '\n', ssize) != NULL) 500 break; 501 } 502 buf[size] = '\0'; 503 /* Read two characters, and check for a delimiting character */ 504 if (sscanf(buf, "%hu , %hu%c", &lport, &fport, &e) != 3 || isdigit(e)) 505 iderror(0, 0, s, ID_INVALID); 506 507 /* Send garbage? */ 508 if (gflag) 509 goto printit; 510 511 /* 512 * If not "real" (-r), send a HIDDEN-USER error for everything. 513 * If -d is used to set a fallback username, this is used to 514 * override it, and the fallback is returned instead. 515 */ 516 if (!rflag) { 517 if (*idbuf == '\0') 518 iderror(lport, fport, s, ID_HIDDEN); 519 goto printit; 520 } 521 522 /* 523 * We take the input and construct an array of two sockaddr_ins 524 * which contain the local address information and foreign 525 * address information, respectively, used to look up the 526 * credentials for the socket (which are returned by the 527 * sysctl "net.inet.tcp.getcred" when we call it.) 528 */ 529 socklen = sizeof(ss[0]); 530 if (getsockname(s, (struct sockaddr *)&ss[0], &socklen) == -1) 531 iderror(lport, fport, s, ID_UNKNOWN); 532 socklen = sizeof(ss[1]); 533 if (getpeername(s, (struct sockaddr *)&ss[1], &socklen) == -1) 534 iderror(lport, fport, s, ID_UNKNOWN); 535 if (ss[0].ss_family != ss[1].ss_family) 536 iderror(lport, fport, s, ID_UNKNOWN); 537 size = sizeof(uc); 538 switch (ss[0].ss_family) { 539 case AF_INET: 540 sin4[0] = *(struct sockaddr_in *)&ss[0]; 541 sin4[0].sin_port = htons(lport); 542 sin4[1] = *(struct sockaddr_in *)&ss[1]; 543 sin4[1].sin_port = htons(fport); 544 if (sysctlbyname("net.inet.tcp.getcred", &uc, &size, sin4, 545 sizeof(sin4)) == -1) 546 getcredfail = errno; 547 break; 548#ifdef INET6 549 case AF_INET6: 550 sin6[0] = *(struct sockaddr_in6 *)&ss[0]; 551 sin6[0].sin6_port = htons(lport); 552 sin6[1] = *(struct sockaddr_in6 *)&ss[1]; 553 sin6[1].sin6_port = htons(fport); 554 if (sysctlbyname("net.inet6.tcp6.getcred", &uc, &size, sin6, 555 sizeof(sin6)) == -1) 556 getcredfail = errno; 557 break; 558#endif 559 default: /* should not reach here */ 560 getcredfail = EAFNOSUPPORT; 561 break; 562 } 563 if (getcredfail != 0 || uc.cr_version != XUCRED_VERSION) { 564 if (*idbuf == '\0') 565 iderror(lport, fport, s, 566 getcredfail == ENOENT ? ID_NOUSER : ID_UNKNOWN); 567 goto printit; 568 } 569 570 /* Look up the pw to get the username and home directory*/ 571 errno = 0; 572 pw = getpwuid(uc.cr_uid); 573 if (pw == NULL) 574 iderror(lport, fport, s, errno == 0 ? ID_NOUSER : ID_UNKNOWN); 575 576 if (iflag) 577 snprintf(idbuf, sizeof(idbuf), "%u", (unsigned)pw->pw_uid); 578 else 579 strlcpy(idbuf, pw->pw_name, sizeof(idbuf)); 580 581 /* 582 * If enabled, we check for a file named ".noident" in the user's 583 * home directory. If found, we return HIDDEN-USER. 584 */ 585 if (nflag) { 586 if (asprintf(&p, "%s/.noident", pw->pw_dir) == -1) 587 iderror(lport, fport, s, ID_UNKNOWN); 588 if (lstat(p, &sb) == 0) { 589 free(p); 590 iderror(lport, fport, s, ID_HIDDEN); 591 } 592 free(p); 593 } 594 595 /* 596 * Here, if enabled, we read a user's ".fakeid" file in their 597 * home directory. It consists of a line containing the name 598 * they want. 599 */ 600 if (fflag) { 601 int fakeid_fd; 602 603 /* 604 * Here we set ourself to effectively be the user, so we don't 605 * open any files we have no permission to open, especially 606 * symbolic links to sensitive root-owned files or devices. 607 */ 608 if (initgroups(pw->pw_name, pw->pw_gid) == -1) 609 iderror(lport, fport, s, ID_UNKNOWN); 610 if (seteuid(pw->pw_uid) == -1) 611 iderror(lport, fport, s, ID_UNKNOWN); 612 /* 613 * We can't stat() here since that would be a race 614 * condition. 615 * Therefore, we open the file we have permissions to open 616 * and if it's not a regular file, we close it and end up 617 * returning the user's real username. 618 */ 619 if (asprintf(&p, "%s/.fakeid", pw->pw_dir) == -1) 620 iderror(lport, fport, s, ID_UNKNOWN); 621 fakeid_fd = open(p, O_RDONLY | O_NONBLOCK); 622 free(p); 623 if (fakeid_fd == -1 || fstat(fakeid_fd, &sb) == -1 || 624 !S_ISREG(sb.st_mode)) 625 goto fakeid_fail; 626 627 if ((ssize = read(fakeid_fd, buf, sizeof(buf) - 1)) < 0) 628 goto fakeid_fail; 629 buf[ssize] = '\0'; 630 631 /* 632 * Usually, the file will have the desired identity 633 * in the form "identity\n". Allow for leading white 634 * space and trailing white space/end of line. 635 */ 636 p = buf; 637 p += strspn(p, " \t"); 638 p[strcspn(p, " \t\r\n")] = '\0'; 639 if (strlen(p) > MAXLOGNAME - 1) /* Too long (including nul)? */ 640 p[MAXLOGNAME - 1] = '\0'; 641 642 /* 643 * If the name is a zero-length string or matches it 644 * the id or name of another user (unless permitted by -F) 645 * then it is invalid. 646 */ 647 if (*p == '\0') 648 goto fakeid_fail; 649 if (!Fflag) { 650 if (iflag) { 651 if (p[strspn(p, "0123456789")] == '\0' && 652 getpwuid(atoi(p)) != NULL) 653 goto fakeid_fail; 654 } else { 655 if (getpwnam(p) != NULL) 656 goto fakeid_fail; 657 } 658 } 659 660 strlcpy(idbuf, p, sizeof(idbuf)); 661 662fakeid_fail: 663 if (fakeid_fd != -1) 664 close(fakeid_fd); 665 } 666 667printit: 668 /* Finally, we make and send the reply. */ 669 if (asprintf(&p, "%d , %d : USERID : %s : %s\r\n", lport, fport, osname, 670 idbuf) == -1) { 671 syslog(LOG_ERR, "asprintf: %m"); 672 exit(EX_OSERR); 673 } 674 send(s, p, strlen(p), MSG_EOF); 675 free(p); 676 677 exit(0); 678} 679 680/* 681 * RFC738/868 Time Server. 682 * Return a machine readable date and time, in the form of the 683 * number of seconds since midnight, Jan 1, 1900. Since gettimeofday 684 * returns the number of seconds since midnight, Jan 1, 1970, 685 * we must add 2208988800 seconds to this figure to make up for 686 * some seventy years Bell Labs was asleep. 687 */ 688 689uint32_t 690machtime(void) 691{ 692 693#define OFFSET ((uint32_t)25567 * 24*60*60) 694 return (htonl((uint32_t)(time(NULL) + OFFSET))); 695#undef OFFSET 696} 697 698/* ARGSUSED */ 699void 700machtime_dg(int s, struct servtab *sep) 701{ 702 uint32_t result; 703 struct sockaddr_storage ss; 704 socklen_t size; 705 706 size = sizeof(ss); 707 if (recvfrom(s, (char *)&result, sizeof(result), 0, 708 (struct sockaddr *)&ss, &size) < 0) 709 return; 710 711 if (check_loop((struct sockaddr *)&ss, sep)) 712 return; 713 714 result = machtime(); 715 (void) sendto(s, (char *) &result, sizeof(result), 0, 716 (struct sockaddr *)&ss, size); 717} 718 719/* ARGSUSED */ 720void 721machtime_stream(int s, struct servtab *sep __unused) 722{ 723 uint32_t result; 724 725 result = machtime(); 726 (void) send(s, (char *) &result, sizeof(result), MSG_EOF); 727} 728 729/* 730 * RFC1078 TCP Port Service Multiplexer (TCPMUX). Service connections to 731 * services based on the service name sent. 732 * 733 * Based on TCPMUX.C by Mark K. Lottor November 1988 734 * sri-nic::ps:<mkl>tcpmux.c 735 */ 736 737#define MAX_SERV_LEN (256+2) /* 2 bytes for \r\n */ 738#define strwrite(fd, buf) (void) write(fd, buf, sizeof(buf)-1) 739 740static int /* # of characters up to \r,\n or \0 */ 741getline(int fd, char *buf, int len) 742{ 743 int count = 0, n; 744 struct sigaction sa; 745 746 sa.sa_flags = 0; 747 sigemptyset(&sa.sa_mask); 748 sa.sa_handler = SIG_DFL; 749 sigaction(SIGALRM, &sa, (struct sigaction *)0); 750 do { 751 alarm(10); 752 n = read(fd, buf, len-count); 753 alarm(0); 754 if (n == 0) 755 return (count); 756 if (n < 0) 757 return (-1); 758 while (--n >= 0) { 759 if (*buf == '\r' || *buf == '\n' || *buf == '\0') 760 return (count); 761 count++; 762 buf++; 763 } 764 } while (count < len); 765 return (count); 766} 767 768struct servtab * 769tcpmux(int s) 770{ 771 struct servtab *sep; 772 char service[MAX_SERV_LEN+1]; 773 int len; 774 775 /* Get requested service name */ 776 if ((len = getline(s, service, MAX_SERV_LEN)) < 0) { 777 strwrite(s, "-Error reading service name\r\n"); 778 return (NULL); 779 } 780 service[len] = '\0'; 781 782 if (debug) 783 warnx("tcpmux: someone wants %s", service); 784 785 /* 786 * Help is a required command, and lists available services, 787 * one per line. 788 */ 789 if (!strcasecmp(service, "help")) { 790 for (sep = servtab; sep; sep = sep->se_next) { 791 if (!ISMUX(sep)) 792 continue; 793 (void)write(s,sep->se_service,strlen(sep->se_service)); 794 strwrite(s, "\r\n"); 795 } 796 return (NULL); 797 } 798 799 /* Try matching a service in inetd.conf with the request */ 800 for (sep = servtab; sep; sep = sep->se_next) { 801 if (!ISMUX(sep)) 802 continue; 803 if (!strcasecmp(service, sep->se_service)) { 804 if (ISMUXPLUS(sep)) { 805 strwrite(s, "+Go\r\n"); 806 } 807 return (sep); 808 } 809 } 810 strwrite(s, "-Service not available\r\n"); 811 return (NULL); 812} 813