identd.c revision 1.2
1 /* 2 ** $Id: identd.c,v 1.2 1994/02/04 23:17:56 cgd Exp $ 3 ** 4 ** identd.c A TCP/IP link identification protocol server 5 ** 6 ** This program is in the public domain and may be used freely by anyone 7 ** who wants to. 8 ** 9 ** Last update: 22 April 1993 10 ** 11 ** Please send bug fixes/bug reports to: Peter Eriksson <pen (at) lysator.liu.se> 12 */ 13 14 #if defined(IRIX) || defined(SVR4) || defined(NeXT) || defined(__NetBSD__) 15 # define SIGRETURN_TYPE void 16 # define SIGRETURN_TYPE_IS_VOID 17 #else 18 # define SIGRETURN_TYPE int 19 #endif 20 21 #ifdef SVR4 22 # define STRNET 23 #endif 24 25 #include <stdio.h> 26 #include <ctype.h> 27 #include <errno.h> 28 #include <netdb.h> 29 #include <signal.h> 30 #include <fcntl.h> 31 32 #include <sys/types.h> 33 #include <sys/param.h> 34 #include <sys/ioctl.h> 35 #include <sys/socket.h> 36 #ifndef _AUX_SOURCE 37 # include <sys/file.h> 38 #endif 39 #include <sys/time.h> 40 #include <sys/wait.h> 41 42 #include <pwd.h> 43 #include <grp.h> 44 45 #include <netinet/in.h> 46 47 #ifndef HPUX7 48 # include <arpa/inet.h> 49 #endif 50 51 #if defined(MIPS) || defined(BSD43) 52 extern int errno; 53 #endif 54 55 #include "identd.h" 56 #include "error.h" 57 58 /* Antique unixes do not have these things defined... */ 59 #ifndef FD_SETSIZE 60 # define FD_SETSIZE 256 61 #endif 62 63 #ifndef FD_SET 64 # ifndef NFDBITS 65 # define NFDBITS (sizeof(int) * NBBY) /* bits per mask */ 66 # endif 67 # define FD_SET(n, p) ((p)->fds_bits[(n)/NFDBITS] |= (1 << ((n) % NFDBITS))) 68 #endif 69 70 #ifndef FD_ZERO 71 # define FD_ZERO(p) bzero((char *)(p), sizeof(*(p))) 72 #endif 73 74 extern char *version; 75 76 extern void *calloc(); 77 extern void *malloc(); 78 79 80 char *path_unix = NULL; 81 char *path_kmem = NULL; 82 83 int verbose_flag = 0; 84 int debug_flag = 0; 85 int syslog_flag = 0; 86 int multi_flag = 0; 87 int other_flag = 0; 88 int unknown_flag = 0; 89 int number_flag = 0; 90 int noident_flag = 0; 91 92 int lport = 0; 93 int fport = 0; 94 95 char *charset_name = NULL; 96 char *indirect_host = NULL; 97 char *indirect_password = NULL; 98 99 static int child_pid; 100 101 #ifdef LOG_DAEMON 102 static int syslog_facility = LOG_DAEMON; 103 #endif 104 105 /* 106 ** The structure passing convention for GCC is incompatible with 107 ** Suns own C compiler, so we define our own inet_ntoa() function. 108 ** (This should only affect GCC version 1 I think, a well, this works 109 ** for version 2 also so why bother.. :-) 110 */ 111 #if defined(__GNUC__) && defined(__sparc__) 112 113 #ifdef inet_ntoa 114 #undef inet_ntoa 115 #endif 116 117 char *inet_ntoa(ad) 118 struct in_addr ad; 119 { 120 unsigned long int s_ad; 121 int a, b, c, d; 122 static char addr[20]; 123 124 s_ad = ad.s_addr; 125 d = s_ad % 256; 126 s_ad /= 256; 127 c = s_ad % 256; 128 s_ad /= 256; 129 b = s_ad % 256; 130 a = s_ad / 256; 131 sprintf(addr, "%d.%d.%d.%d", a, b, c, d); 132 133 return addr; 134 } 135 #endif 136 137 138 /* 139 ** Return the name of the connecting host, or the IP number as a string. 140 */ 141 char *gethost(addr) 142 struct in_addr *addr; 143 { 144 struct hostent *hp; 145 146 147 hp = gethostbyaddr((char *) addr, sizeof(struct in_addr), AF_INET); 148 if (hp) 149 return hp->h_name; 150 else 151 return inet_ntoa(*addr); 152 } 153 154 /* 155 ** Exit cleanly after our time's up. 156 */ 157 static SIGRETURN_TYPE 158 alarm_handler() 159 { 160 if (syslog_flag) 161 syslog(LOG_DEBUG, "SIGALRM triggered, exiting"); 162 163 exit(0); 164 } 165 166 #if !defined(hpux) && !defined(__hpux) && !defined(SVR4) || defined(_CRAY) 167 /* 168 ** This is used to clean up zombie child processes 169 ** if the -w or -b options are used. 170 */ 171 static SIGRETURN_TYPE 172 child_handler() 173 { 174 #if defined(IRIX) || defined(NeXT) 175 union wait status; 176 #else 177 int status; 178 #endif 179 180 while (wait3(&status, WNOHANG, NULL) > 0) 181 ; 182 183 #ifndef SIGRETURN_TYPE_IS_VOID 184 return 0; 185 #endif 186 } 187 #endif 188 189 190 char *clearmem(bp, len) 191 char *bp; 192 int len; 193 { 194 char *cp; 195 196 cp = bp; 197 while (len-- > 0) 198 *cp++ = 0; 199 200 return bp; 201 } 202 203 204 /* 205 ** Main entry point into this daemon 206 */ 207 int main(argc,argv) 208 int argc; 209 char *argv[]; 210 { 211 int i, len; 212 struct sockaddr_in sin; 213 struct in_addr laddr, faddr; 214 struct timeval tv; 215 216 int background_flag = 0; 217 int timeout = 0; 218 char *portno = "113"; 219 char *bind_address = NULL; 220 int set_uid = 0; 221 int set_gid = 0; 222 int inhibit_default_config = 0; 223 int opt_count = 0; /* Count of option flags */ 224 225 #ifdef __convex__ 226 argc--; /* get rid of extra argument passed by inetd */ 227 #endif 228 229 /* 230 ** Prescan the arguments for "-f<config-file>" switches 231 */ 232 inhibit_default_config = 0; 233 for (i = 1; i < argc && argv[i][0] == '-'; i++) 234 if (argv[i][1] == 'f') 235 inhibit_default_config = 1; 236 237 /* 238 ** Parse the default config file - if it exists 239 */ 240 if (!inhibit_default_config) 241 parse_config(NULL, 1); 242 243 /* 244 ** Parse the command line arguments 245 */ 246 for (i = 1; i < argc && argv[i][0] == '-'; i++) { 247 opt_count++; 248 switch (argv[i][1]) 249 { 250 case 'b': /* Start as standalone daemon */ 251 background_flag = 1; 252 break; 253 254 case 'w': /* Start from Inetd, wait mode */ 255 background_flag = 2; 256 break; 257 258 case 'i': /* Start from Inetd, nowait mode */ 259 background_flag = 0; 260 break; 261 262 case 't': 263 timeout = atoi(argv[i]+2); 264 break; 265 266 case 'p': 267 portno = argv[i]+2; 268 break; 269 270 case 'a': 271 bind_address = argv[i]+2; 272 break; 273 274 case 'u': 275 if (isdigit(argv[i][2])) 276 set_uid = atoi(argv[i]+2); 277 else 278 { 279 struct passwd *pwd; 280 281 pwd = getpwnam(argv[i]+2); 282 if (!pwd) 283 ERROR1("no such user (%s) for -u option", argv[i]+2); 284 else 285 { 286 set_uid = pwd->pw_uid; 287 set_gid = pwd->pw_gid; 288 } 289 } 290 break; 291 292 case 'g': 293 if (isdigit(argv[i][2])) 294 set_gid = atoi(argv[i]+2); 295 else 296 { 297 struct group *grp; 298 299 grp = getgrnam(argv[i]+2); 300 if (!grp) 301 ERROR1("no such group (%s) for -g option", argv[i]+2); 302 else 303 set_gid = grp->gr_gid; 304 } 305 break; 306 307 case 'c': 308 charset_name = argv[i]+2; 309 break; 310 311 case 'r': 312 indirect_host = argv[i]+2; 313 break; 314 315 case 'l': /* Use the Syslog daemon for logging */ 316 syslog_flag++; 317 break; 318 319 case 'o': 320 other_flag = 1; 321 break; 322 323 case 'e': 324 unknown_flag = 1; 325 break; 326 327 case 'n': 328 number_flag = 1; 329 break; 330 331 case 'V': /* Give version of this daemon */ 332 printf("[in.identd, version %s]\r\n", version); 333 exit(0); 334 break; 335 336 case 'v': /* Be verbose */ 337 verbose_flag++; 338 break; 339 340 case 'd': /* Enable debugging */ 341 debug_flag++; 342 break; 343 344 case 'm': /* Enable multiline queries */ 345 multi_flag++; 346 break; 347 348 case 'N': /* Enable users ".noident" files */ 349 noident_flag++; 350 break; 351 } 352 } 353 354 #if defined(_AUX_SOURCE) || defined (SUNOS35) 355 /* A/UX 2.0* & SunOS 3.5 calls us with an argument XXXXXXXX.YYYY 356 ** where XXXXXXXXX is the hexadecimal version of the callers 357 ** IP number, and YYYY is the port/socket or something. 358 ** It seems to be impossible to pass arguments to a daemon started 359 ** by inetd. 360 ** 361 ** Just in case it is started from something else, then we only 362 ** skip the argument if no option flags have been seen. 363 */ 364 if (opt_count == 0) 365 argc--; 366 #endif 367 368 /* 369 ** Path to kernel namelist file specified on command line 370 */ 371 if (i < argc) 372 path_unix = argv[i++]; 373 374 /* 375 ** Path to kernel memory device specified on command line 376 */ 377 if (i < argc) 378 path_kmem = argv[i++]; 379 380 381 /* 382 ** Open the kernel memory device and read the nlist table 383 */ 384 if (k_open() < 0) 385 ERROR("main: k_open"); 386 387 /* 388 ** Do the special handling needed for the "-b" flag 389 */ 390 if (background_flag == 1) 391 { 392 struct sockaddr_in addr; 393 struct servent *sp; 394 int fd; 395 396 397 if (fork()) 398 exit(0); 399 400 close(0); 401 close(1); 402 close(2); 403 404 if (fork()) 405 exit(0); 406 407 fd = socket(AF_INET, SOCK_STREAM, 0); 408 if (fd == -1) 409 ERROR("main: socket"); 410 411 if (fd != 0) 412 dup2(fd, 0); 413 414 clearmem(&addr, sizeof(addr)); 415 416 addr.sin_family = AF_INET; 417 if (bind_address == NULL) 418 addr.sin_addr.s_addr = htonl(INADDR_ANY); 419 else 420 { 421 if (isdigit(bind_address[0])) 422 addr.sin_addr.s_addr = inet_addr(bind_address); 423 else 424 { 425 struct hostent *hp; 426 427 hp = gethostbyname(bind_address); 428 if (!hp) 429 ERROR1("no such address (%s) for -a switch", bind_address); 430 431 /* This is ugly, should use memcpy() or bcopy() but... */ 432 addr.sin_addr.s_addr = * (unsigned long *) (hp->h_addr); 433 } 434 } 435 436 if (isdigit(portno[0])) 437 addr.sin_port = htons(atoi(portno)); 438 else 439 { 440 sp = getservbyname(portno, "tcp"); 441 if (sp == NULL) 442 ERROR1("main: getservbyname: %s", portno); 443 addr.sin_port = sp->s_port; 444 } 445 446 if (bind(0, (struct sockaddr *) &addr, sizeof(addr)) < 0) 447 ERROR("main: bind"); 448 449 if (listen(0, 3) < 0) 450 ERROR("main: listen"); 451 } 452 453 if (set_gid) 454 if (setgid(set_gid) == -1) 455 ERROR("main: setgid"); 456 457 if (set_uid) 458 if (setuid(set_uid) == -1) 459 ERROR("main: setuid"); 460 461 /* 462 ** Do some special handling if the "-b" or "-w" flags are used 463 */ 464 if (background_flag) 465 { 466 int nfds, fd; 467 fd_set read_set; 468 469 470 /* 471 ** Set up the SIGCHLD signal child termination handler so 472 ** that we can avoid zombie processes hanging around and 473 ** handle childs terminating before being able to complete the 474 ** handshake. 475 */ 476 #if (defined(SVR4) || defined(hpux) || defined(__hpux) || \ 477 defined(_CRAY) || defined(_AUX_SOURCE)) 478 signal(SIGCHLD, SIG_IGN); 479 #else 480 signal(SIGCHLD, (SIGRETURN_TYPE (*)()) child_handler); 481 #endif 482 483 /* 484 ** Loop and dispatch client handling processes 485 */ 486 do 487 { 488 /* 489 ** Terminate if we've been idle for 'timeout' seconds 490 */ 491 if (background_flag == 2 && timeout) 492 { 493 signal(SIGALRM, alarm_handler); 494 alarm(timeout); 495 } 496 497 /* 498 ** Wait for a connection request to occur. 499 ** Ignore EINTR (Interrupted System Call). 500 */ 501 do 502 { 503 FD_ZERO(&read_set); 504 FD_SET(0, &read_set); 505 506 if (timeout) 507 { 508 tv.tv_sec = timeout; 509 tv.tv_usec = 0; 510 nfds = select(FD_SETSIZE, &read_set, NULL, NULL, &tv); 511 } 512 else 513 514 nfds = select(FD_SETSIZE, &read_set, NULL, NULL, NULL); 515 } while (nfds < 0 && errno == EINTR); 516 517 /* 518 ** An error occured in select? Just die 519 */ 520 if (nfds < 0) 521 ERROR("main: select"); 522 523 /* 524 ** Timeout limit reached. Exit nicely 525 */ 526 if (nfds == 0) 527 exit(0); 528 529 /* 530 ** Disable the alarm timeout 531 */ 532 alarm(0); 533 534 /* 535 ** Accept the new client 536 */ 537 fd = accept(0, NULL, NULL); 538 if (fd == -1) 539 ERROR1("main: accept. errno = %d", errno); 540 541 /* 542 ** And fork, then close the fd if we are the parent. 543 */ 544 child_pid = fork(); 545 } while (child_pid && (close(fd), 1)); 546 547 /* 548 ** We are now in child, the parent has returned to "do" above. 549 */ 550 if (dup2(fd, 0) == -1) 551 ERROR("main: dup2: failed fd 0"); 552 553 if (dup2(fd, 1) == -1) 554 ERROR("main: dup2: failed fd 1"); 555 556 if (dup2(fd, 2) == -1) 557 ERROR("main: dup2: failed fd 2"); 558 } 559 560 /* 561 ** Get foreign internet address 562 */ 563 len = sizeof(sin); 564 if (getpeername(0, (struct sockaddr *) &sin, &len) == -1) 565 { 566 /* 567 ** A user has tried to start us from the command line or 568 ** the network link died, in which case this message won't 569 ** reach to other end anyway, so lets give the poor user some 570 ** errors. 571 */ 572 perror("in.identd: getpeername()"); 573 exit(1); 574 } 575 576 faddr = sin.sin_addr; 577 578 579 /* 580 ** Open the connection to the Syslog daemon if requested 581 */ 582 if (syslog_flag) 583 { 584 #ifdef LOG_DAEMON 585 openlog("identd", LOG_PID, syslog_facility); 586 #else 587 openlog("identd", LOG_PID); 588 #endif 589 590 syslog(LOG_INFO, "Connection from %s", gethost(&faddr)); 591 } 592 593 594 /* 595 ** Get local internet address 596 */ 597 len = sizeof(sin); 598 #ifdef ATTSVR4 599 if (t_getsockname(0, (struct sockaddr *) &sin, &len) == -1) 600 #else 601 if (getsockname(0, (struct sockaddr *) &sin, &len) == -1) 602 #endif 603 { 604 /* 605 ** We can just die here, because if this fails then the 606 ** network has died and we haven't got anyone to return 607 ** errors to. 608 */ 609 exit(1); 610 } 611 laddr = sin.sin_addr; 612 613 614 /* 615 ** Get the local/foreign port pair from the luser 616 */ 617 parse(stdin, &laddr, &faddr); 618 619 exit(0); 620 } 621
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