1 /* 2 * Copyright (c) 1983, 1993 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 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 #ifndef lint 35 static const char copyright[] = 36 "@(#) Copyright (c) 1983, 1993\n\ 37 The Regents of the University of California. All rights reserved.\n"; 38 #endif /* not lint */ 39 40 #ifndef lint 41 #if 0 42 static char sccsid[] = "@(#)tftpd.c 8.1 (Berkeley) 6/4/93"; 43 #endif 44 static const char rcsid[] = 45 "$FreeBSD$"; 46 #endif /* not lint */ 47 48 /* 49 * Trivial file transfer protocol server. 50 * 51 * This version includes many modifications by Jim Guyton 52 * <guyton@rand-unix>. 53 */ 54 55 #include <sys/param.h> 56 #include <sys/ioctl.h> 57 #include <sys/stat.h> 58 #include <sys/socket.h> 59 #include <sys/types.h> 60 #include <sys/time.h> 61 62 #include <netinet/in.h> 63 #include <arpa/tftp.h> 64 #include <arpa/inet.h> 65 66 #include <ctype.h> 67 #include <errno.h> 68 #include <fcntl.h> 69 #include <libutil.h> 70 #include <netdb.h> 71 #include <pwd.h> 72 #include <setjmp.h> 73 #include <signal.h> 74 #include <stdio.h> 75 #include <stdlib.h> 76 #include <string.h> 77 #include <syslog.h> 78 #include <unistd.h> 79 80 #include "tftpsubs.h" 81 82 #define TIMEOUT 5 83 #define MAX_TIMEOUTS 5 84 85 int peer; 86 int rexmtval = TIMEOUT; 87 int max_rexmtval = 2*TIMEOUT; 88 89 #define PKTSIZE SEGSIZE+4 90 char buf[PKTSIZE]; 91 char ackbuf[PKTSIZE]; 92 struct sockaddr_storage from; 93 int fromlen; 94 95 void tftp(struct tftphdr *, int); 96 static void unmappedaddr(struct sockaddr_in6 *); 97 98 /* 99 * Null-terminated directory prefix list for absolute pathname requests and 100 * search list for relative pathname requests. 101 * 102 * MAXDIRS should be at least as large as the number of arguments that 103 * inetd allows (currently 20). 104 */ 105 #define MAXDIRS 20 106 static struct dirlist { 107 const char *name; 108 int len; 109 } dirs[MAXDIRS+1]; 110 static int suppress_naks; 111 static int logging; 112 static int ipchroot; 113 static int create_new = 0; 114 static mode_t mask = S_IWGRP|S_IWOTH; 115 116 static const char *errtomsg(int); 117 static void nak(int); 118 static void oack(void); 119 120 static void timer(int); 121 static void justquit(int); 122 123 int 124 main(int argc, char *argv[]) 125 { 126 struct tftphdr *tp; 127 int n; 128 int ch, on; 129 struct sockaddr_storage me; 130 int len; 131 char *chroot_dir = NULL; 132 struct passwd *nobody; 133 const char *chuser = "nobody"; 134 135 tzset(); /* syslog in localtime */ 136 137 openlog("tftpd", LOG_PID | LOG_NDELAY, LOG_FTP); 138 while ((ch = getopt(argc, argv, "cClns:u:Uw")) != -1) { 139 switch (ch) { 140 case 'c': 141 ipchroot = 1; 142 break; 143 case 'C': 144 ipchroot = 2; 145 break; 146 case 'l': 147 logging = 1; 148 break; 149 case 'n': 150 suppress_naks = 1; 151 break; 152 case 's': 153 chroot_dir = optarg; 154 break; 155 case 'u': 156 chuser = optarg; 157 break; 158 case 'U': 159 mask = strtol(optarg, NULL, 0); 160 break; 161 case 'w': 162 create_new = 1; 163 break; 164 default: 165 syslog(LOG_WARNING, "ignoring unknown option -%c", ch); 166 } 167 } 168 if (optind < argc) { 169 struct dirlist *dirp; 170 171 /* Get list of directory prefixes. Skip relative pathnames. */ 172 for (dirp = dirs; optind < argc && dirp < &dirs[MAXDIRS]; 173 optind++) { 174 if (argv[optind][0] == '/') { 175 dirp->name = argv[optind]; 176 dirp->len = strlen(dirp->name); 177 dirp++; 178 } 179 } 180 } 181 else if (chroot_dir) { 182 dirs->name = "/"; 183 dirs->len = 1; 184 } 185 if (ipchroot > 0 && chroot_dir == NULL) { 186 syslog(LOG_ERR, "-c requires -s"); 187 exit(1); 188 } 189 190 umask(mask); 191 192 on = 1; 193 if (ioctl(0, FIONBIO, &on) < 0) { 194 syslog(LOG_ERR, "ioctl(FIONBIO): %m"); 195 exit(1); 196 } 197 fromlen = sizeof (from); 198 n = recvfrom(0, buf, sizeof (buf), 0, 199 (struct sockaddr *)&from, &fromlen); 200 if (n < 0) { 201 syslog(LOG_ERR, "recvfrom: %m"); 202 exit(1); 203 } 204 /* 205 * Now that we have read the message out of the UDP 206 * socket, we fork and exit. Thus, inetd will go back 207 * to listening to the tftp port, and the next request 208 * to come in will start up a new instance of tftpd. 209 * 210 * We do this so that inetd can run tftpd in "wait" mode. 211 * The problem with tftpd running in "nowait" mode is that 212 * inetd may get one or more successful "selects" on the 213 * tftp port before we do our receive, so more than one 214 * instance of tftpd may be started up. Worse, if tftpd 215 * break before doing the above "recvfrom", inetd would 216 * spawn endless instances, clogging the system. 217 */ 218 { 219 int pid; 220 int i, j; 221 222 for (i = 1; i < 20; i++) { 223 pid = fork(); 224 if (pid < 0) { 225 sleep(i); 226 /* 227 * flush out to most recently sent request. 228 * 229 * This may drop some request, but those 230 * will be resent by the clients when 231 * they timeout. The positive effect of 232 * this flush is to (try to) prevent more 233 * than one tftpd being started up to service 234 * a single request from a single client. 235 */ 236 j = sizeof from; 237 i = recvfrom(0, buf, sizeof (buf), 0, 238 (struct sockaddr *)&from, &j); 239 if (i > 0) { 240 n = i; 241 fromlen = j; 242 } 243 } else { 244 break; 245 } 246 } 247 if (pid < 0) { 248 syslog(LOG_ERR, "fork: %m"); 249 exit(1); 250 } else if (pid != 0) { 251 exit(0); 252 } 253 } 254 255 /* 256 * Since we exit here, we should do that only after the above 257 * recvfrom to keep inetd from constantly forking should there 258 * be a problem. See the above comment about system clogging. 259 */ 260 if (chroot_dir) { 261 if (ipchroot > 0) { 262 char *tempchroot; 263 struct stat sb; 264 int statret; 265 struct sockaddr_storage ss; 266 char hbuf[NI_MAXHOST]; 267 268 memcpy(&ss, &from, from.ss_len); 269 unmappedaddr((struct sockaddr_in6 *)&ss); 270 getnameinfo((struct sockaddr *)&ss, ss.ss_len, 271 hbuf, sizeof(hbuf), NULL, 0, 272 NI_NUMERICHOST | NI_WITHSCOPEID); 273 asprintf(&tempchroot, "%s/%s", chroot_dir, hbuf); 274 if (ipchroot == 2) 275 statret = stat(tempchroot, &sb); 276 if (ipchroot == 1 || 277 (statret == 0 && (sb.st_mode & S_IFDIR))) 278 chroot_dir = tempchroot; 279 } 280 /* Must get this before chroot because /etc might go away */ 281 if ((nobody = getpwnam(chuser)) == NULL) { 282 syslog(LOG_ERR, "%s: no such user", chuser); 283 exit(1); 284 } 285 if (chroot(chroot_dir)) { 286 syslog(LOG_ERR, "chroot: %s: %m", chroot_dir); 287 exit(1); 288 } 289 chdir("/"); 290 setgroups(1, &nobody->pw_gid); 291 setuid(nobody->pw_uid); 292 } 293 294 len = sizeof(me); 295 if (getsockname(0, (struct sockaddr *)&me, &len) == 0) { 296 switch (me.ss_family) { 297 case AF_INET: 298 ((struct sockaddr_in *)&me)->sin_port = 0; 299 break; 300 case AF_INET6: 301 ((struct sockaddr_in6 *)&me)->sin6_port = 0; 302 break; 303 default: 304 /* unsupported */ 305 break; 306 } 307 } else { 308 memset(&me, 0, sizeof(me)); 309 me.ss_family = from.ss_family; 310 me.ss_len = from.ss_len; 311 } 312 alarm(0); 313 close(0); 314 close(1); 315 peer = socket(from.ss_family, SOCK_DGRAM, 0); 316 if (peer < 0) { 317 syslog(LOG_ERR, "socket: %m"); 318 exit(1); 319 } 320 if (bind(peer, (struct sockaddr *)&me, me.ss_len) < 0) { 321 syslog(LOG_ERR, "bind: %m"); 322 exit(1); 323 } 324 if (connect(peer, (struct sockaddr *)&from, from.ss_len) < 0) { 325 syslog(LOG_ERR, "connect: %m"); 326 exit(1); 327 } 328 tp = (struct tftphdr *)buf; 329 tp->th_opcode = ntohs(tp->th_opcode); 330 if (tp->th_opcode == RRQ || tp->th_opcode == WRQ) 331 tftp(tp, n); 332 exit(1); 333 } 334 335 static void 336 reduce_path(char *fn) 337 { 338 char *slash, *ptr; 339 340 /* Reduce all "/+./" to "/" (just in case we've got "/./../" later */ 341 while ((slash = strstr(fn, "/./")) != NULL) { 342 for (ptr = slash; ptr > fn && ptr[-1] == '/'; ptr--) 343 ; 344 slash += 2; 345 while (*slash) 346 *++ptr = *++slash; 347 } 348 349 /* Now reduce all "/something/+../" to "/" */ 350 while ((slash = strstr(fn, "/../")) != NULL) { 351 if (slash == fn) 352 break; 353 for (ptr = slash; ptr > fn && ptr[-1] == '/'; ptr--) 354 ; 355 for (ptr--; ptr >= fn; ptr--) 356 if (*ptr == '/') 357 break; 358 if (ptr < fn) 359 break; 360 slash += 3; 361 while (*slash) 362 *++ptr = *++slash; 363 } 364 } 365 366 struct formats; 367 int validate_access(char **, int); 368 void xmitfile(struct formats *); 369 void recvfile(struct formats *); 370 371 struct formats { 372 const char *f_mode; 373 int (*f_validate)(char **, int); 374 void (*f_send)(struct formats *); 375 void (*f_recv)(struct formats *); 376 int f_convert; 377 } formats[] = { 378 { "netascii", validate_access, xmitfile, recvfile, 1 }, 379 { "octet", validate_access, xmitfile, recvfile, 0 }, 380 #ifdef notdef 381 { "mail", validate_user, sendmail, recvmail, 1 }, 382 #endif 383 { 0, NULL, NULL, NULL, 0 } 384 }; 385 386 struct options { 387 const char *o_type; 388 char *o_request; 389 int o_reply; /* turn into union if need be */ 390 } options[] = { 391 { "tsize", NULL, 0 }, /* OPT_TSIZE */ 392 { "timeout", NULL, 0 }, /* OPT_TIMEOUT */ 393 { NULL, NULL, 0 } 394 }; 395 396 enum opt_enum { 397 OPT_TSIZE = 0, 398 OPT_TIMEOUT, 399 }; 400 401 /* 402 * Handle initial connection protocol. 403 */ 404 void 405 tftp(struct tftphdr *tp, int size) 406 { 407 char *cp; 408 int i, first = 1, has_options = 0, ecode; 409 struct formats *pf; 410 char *filename, *mode, *option, *ccp; 411 char fnbuf[PATH_MAX], resolved_fnbuf[PATH_MAX]; 412 413 cp = tp->th_stuff; 414 again: 415 while (cp < buf + size) { 416 if (*cp == '\0') 417 break; 418 cp++; 419 } 420 if (*cp != '\0') { 421 nak(EBADOP); 422 exit(1); 423 } 424 i = cp - tp->th_stuff; 425 if (i >= sizeof(fnbuf)) { 426 nak(EBADOP); 427 exit(1); 428 } 429 memcpy(fnbuf, tp->th_stuff, i); 430 fnbuf[i] = '\0'; 431 reduce_path(fnbuf); 432 filename = fnbuf; 433 if (first) { 434 mode = ++cp; 435 first = 0; 436 goto again; 437 } 438 for (cp = mode; *cp; cp++) 439 if (isupper(*cp)) 440 *cp = tolower(*cp); 441 for (pf = formats; pf->f_mode; pf++) 442 if (strcmp(pf->f_mode, mode) == 0) 443 break; 444 if (pf->f_mode == 0) { 445 nak(EBADOP); 446 exit(1); 447 } 448 while (++cp < buf + size) { 449 for (i = 2, ccp = cp; i > 0; ccp++) { 450 if (ccp >= buf + size) { 451 /* 452 * Don't reject the request, just stop trying 453 * to parse the option and get on with it. 454 * Some Apple Open Firmware versions have 455 * trailing garbage on the end of otherwise 456 * valid requests. 457 */ 458 goto option_fail; 459 } else if (*ccp == '\0') 460 i--; 461 } 462 for (option = cp; *cp; cp++) 463 if (isupper(*cp)) 464 *cp = tolower(*cp); 465 for (i = 0; options[i].o_type != NULL; i++) 466 if (strcmp(option, options[i].o_type) == 0) { 467 options[i].o_request = ++cp; 468 has_options = 1; 469 } 470 cp = ccp-1; 471 } 472 473 option_fail: 474 if (options[OPT_TIMEOUT].o_request) { 475 int to = atoi(options[OPT_TIMEOUT].o_request); 476 if (to < 1 || to > 255) { 477 nak(EBADOP); 478 exit(1); 479 } 480 else if (to <= max_rexmtval) 481 options[OPT_TIMEOUT].o_reply = rexmtval = to; 482 else 483 options[OPT_TIMEOUT].o_request = NULL; 484 } 485 486 ecode = (*pf->f_validate)(&filename, tp->th_opcode); 487 if (has_options && ecode == 0) 488 oack(); 489 if (logging) { 490 char hbuf[NI_MAXHOST]; 491 492 getnameinfo((struct sockaddr *)&from, from.ss_len, 493 hbuf, sizeof(hbuf), NULL, 0, 494 NI_WITHSCOPEID); 495 syslog(LOG_INFO, "%s: %s request for %s: %s", hbuf, 496 tp->th_opcode == WRQ ? "write" : "read", 497 filename, errtomsg(ecode)); 498 } 499 if (ecode) { 500 /* 501 * Avoid storms of naks to a RRQ broadcast for a relative 502 * bootfile pathname from a diskless Sun. 503 */ 504 if (suppress_naks && *filename != '/' && ecode == ENOTFOUND) 505 exit(0); 506 nak(ecode); 507 exit(1); 508 } 509 if (tp->th_opcode == WRQ) 510 (*pf->f_recv)(pf); 511 else 512 (*pf->f_send)(pf); 513 exit(0); 514 } 515 516 517 FILE *file; 518 519 /* 520 * Validate file access. Since we 521 * have no uid or gid, for now require 522 * file to exist and be publicly 523 * readable/writable. 524 * If we were invoked with arguments 525 * from inetd then the file must also be 526 * in one of the given directory prefixes. 527 * Note also, full path name must be 528 * given as we have no login directory. 529 */ 530 int 531 validate_access(char **filep, int mode) 532 { 533 struct stat stbuf; 534 int fd; 535 struct dirlist *dirp; 536 static char pathname[MAXPATHLEN]; 537 char *filename = *filep; 538 539 /* 540 * Prevent tricksters from getting around the directory restrictions 541 */ 542 if (strstr(filename, "/../")) 543 return (EACCESS); 544 545 if (*filename == '/') { 546 /* 547 * Allow the request if it's in one of the approved locations. 548 * Special case: check the null prefix ("/") by looking 549 * for length = 1 and relying on the arg. processing that 550 * it's a /. 551 */ 552 for (dirp = dirs; dirp->name != NULL; dirp++) { 553 if (dirp->len == 1 || 554 (!strncmp(filename, dirp->name, dirp->len) && 555 filename[dirp->len] == '/')) 556 break; 557 } 558 /* If directory list is empty, allow access to any file */ 559 if (dirp->name == NULL && dirp != dirs) 560 return (EACCESS); 561 if (stat(filename, &stbuf) < 0) 562 return (errno == ENOENT ? ENOTFOUND : EACCESS); 563 if ((stbuf.st_mode & S_IFMT) != S_IFREG) 564 return (ENOTFOUND); 565 if (mode == RRQ) { 566 if ((stbuf.st_mode & S_IROTH) == 0) 567 return (EACCESS); 568 } else { 569 if ((stbuf.st_mode & S_IWOTH) == 0) 570 return (EACCESS); 571 } 572 } else { 573 int err; 574 575 /* 576 * Relative file name: search the approved locations for it. 577 * Don't allow write requests that avoid directory 578 * restrictions. 579 */ 580 581 if (!strncmp(filename, "../", 3)) 582 return (EACCESS); 583 584 /* 585 * If the file exists in one of the directories and isn't 586 * readable, continue looking. However, change the error code 587 * to give an indication that the file exists. 588 */ 589 err = ENOTFOUND; 590 for (dirp = dirs; dirp->name != NULL; dirp++) { 591 snprintf(pathname, sizeof(pathname), "%s/%s", 592 dirp->name, filename); 593 if (stat(pathname, &stbuf) == 0 && 594 (stbuf.st_mode & S_IFMT) == S_IFREG) { 595 if ((stbuf.st_mode & S_IROTH) != 0) { 596 break; 597 } 598 err = EACCESS; 599 } 600 } 601 if (dirp->name != NULL) 602 *filep = filename = pathname; 603 else if (mode == RRQ) 604 return (err); 605 } 606 if (options[OPT_TSIZE].o_request) { 607 if (mode == RRQ) 608 options[OPT_TSIZE].o_reply = stbuf.st_size; 609 else 610 /* XXX Allows writes of all sizes. */ 611 options[OPT_TSIZE].o_reply = 612 atoi(options[OPT_TSIZE].o_request); 613 } 614 if (mode == RRQ) 615 fd = open(filename, O_RDONLY); 616 else { 617 if (create_new) 618 fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0666); 619 else 620 fd = open(filename, O_WRONLY|O_TRUNC); 621 } 622 if (fd < 0) 623 return (errno + 100); 624 file = fdopen(fd, (mode == RRQ)? "r":"w"); 625 if (file == NULL) { 626 close(fd); 627 return (errno + 100); 628 } 629 return (0); 630 } 631 632 int timeouts; 633 jmp_buf timeoutbuf; 634 635 void 636 timer(int sig __unused) 637 { 638 if (++timeouts > MAX_TIMEOUTS) 639 exit(1); 640 longjmp(timeoutbuf, 1); 641 } 642 643 /* 644 * Send the requested file. 645 */ 646 void 647 xmitfile(struct formats *pf) 648 { 649 struct tftphdr *dp; 650 struct tftphdr *ap; /* ack packet */ 651 int size, n; 652 volatile unsigned short block; 653 654 signal(SIGALRM, timer); 655 dp = r_init(); 656 ap = (struct tftphdr *)ackbuf; 657 block = 1; 658 do { 659 size = readit(file, &dp, pf->f_convert); 660 if (size < 0) { 661 nak(errno + 100); 662 goto abort; 663 } 664 dp->th_opcode = htons((u_short)DATA); 665 dp->th_block = htons((u_short)block); 666 timeouts = 0; 667 (void)setjmp(timeoutbuf); 668 669 send_data: 670 { 671 int i, t = 1; 672 for (i = 0; ; i++){ 673 if (send(peer, dp, size + 4, 0) != size + 4) { 674 sleep(t); 675 t = (t < 32) ? t<< 1 : t; 676 if (i >= 12) { 677 syslog(LOG_ERR, "write: %m"); 678 goto abort; 679 } 680 } 681 break; 682 } 683 } 684 read_ahead(file, pf->f_convert); 685 for ( ; ; ) { 686 alarm(rexmtval); /* read the ack */ 687 n = recv(peer, ackbuf, sizeof (ackbuf), 0); 688 alarm(0); 689 if (n < 0) { 690 syslog(LOG_ERR, "read: %m"); 691 goto abort; 692 } 693 ap->th_opcode = ntohs((u_short)ap->th_opcode); 694 ap->th_block = ntohs((u_short)ap->th_block); 695 696 if (ap->th_opcode == ERROR) 697 goto abort; 698 699 if (ap->th_opcode == ACK) { 700 if (ap->th_block == block) 701 break; 702 /* Re-synchronize with the other side */ 703 (void) synchnet(peer); 704 if (ap->th_block == (block -1)) 705 goto send_data; 706 } 707 708 } 709 block++; 710 } while (size == SEGSIZE); 711 abort: 712 (void) fclose(file); 713 } 714 715 void 716 justquit(int sig __unused) 717 { 718 exit(0); 719 } 720 721 722 /* 723 * Receive a file. 724 */ 725 void 726 recvfile(struct formats *pf) 727 { 728 struct tftphdr *dp; 729 struct tftphdr *ap; /* ack buffer */ 730 int n, size; 731 volatile unsigned short block; 732 733 signal(SIGALRM, timer); 734 dp = w_init(); 735 ap = (struct tftphdr *)ackbuf; 736 block = 0; 737 do { 738 timeouts = 0; 739 ap->th_opcode = htons((u_short)ACK); 740 ap->th_block = htons((u_short)block); 741 block++; 742 (void) setjmp(timeoutbuf); 743 send_ack: 744 if (send(peer, ackbuf, 4, 0) != 4) { 745 syslog(LOG_ERR, "write: %m"); 746 goto abort; 747 } 748 write_behind(file, pf->f_convert); 749 for ( ; ; ) { 750 alarm(rexmtval); 751 n = recv(peer, dp, PKTSIZE, 0); 752 alarm(0); 753 if (n < 0) { /* really? */ 754 syslog(LOG_ERR, "read: %m"); 755 goto abort; 756 } 757 dp->th_opcode = ntohs((u_short)dp->th_opcode); 758 dp->th_block = ntohs((u_short)dp->th_block); 759 if (dp->th_opcode == ERROR) 760 goto abort; 761 if (dp->th_opcode == DATA) { 762 if (dp->th_block == block) { 763 break; /* normal */ 764 } 765 /* Re-synchronize with the other side */ 766 (void) synchnet(peer); 767 if (dp->th_block == (block-1)) 768 goto send_ack; /* rexmit */ 769 } 770 } 771 /* size = write(file, dp->th_data, n - 4); */ 772 size = writeit(file, &dp, n - 4, pf->f_convert); 773 if (size != (n-4)) { /* ahem */ 774 if (size < 0) nak(errno + 100); 775 else nak(ENOSPACE); 776 goto abort; 777 } 778 } while (size == SEGSIZE); 779 write_behind(file, pf->f_convert); 780 (void) fclose(file); /* close data file */ 781 782 ap->th_opcode = htons((u_short)ACK); /* send the "final" ack */ 783 ap->th_block = htons((u_short)(block)); 784 (void) send(peer, ackbuf, 4, 0); 785 786 signal(SIGALRM, justquit); /* just quit on timeout */ 787 alarm(rexmtval); 788 n = recv(peer, buf, sizeof (buf), 0); /* normally times out and quits */ 789 alarm(0); 790 if (n >= 4 && /* if read some data */ 791 dp->th_opcode == DATA && /* and got a data block */ 792 block == dp->th_block) { /* then my last ack was lost */ 793 (void) send(peer, ackbuf, 4, 0); /* resend final ack */ 794 } 795 abort: 796 return; 797 } 798 799 struct errmsg { 800 int e_code; 801 const char *e_msg; 802 } errmsgs[] = { 803 { EUNDEF, "Undefined error code" }, 804 { ENOTFOUND, "File not found" }, 805 { EACCESS, "Access violation" }, 806 { ENOSPACE, "Disk full or allocation exceeded" }, 807 { EBADOP, "Illegal TFTP operation" }, 808 { EBADID, "Unknown transfer ID" }, 809 { EEXISTS, "File already exists" }, 810 { ENOUSER, "No such user" }, 811 { EOPTNEG, "Option negotiation" }, 812 { -1, 0 } 813 }; 814 815 static const char * 816 errtomsg(int error) 817 { 818 static char ebuf[20]; 819 struct errmsg *pe; 820 if (error == 0) 821 return "success"; 822 for (pe = errmsgs; pe->e_code >= 0; pe++) 823 if (pe->e_code == error) 824 return pe->e_msg; 825 snprintf(ebuf, sizeof(buf), "error %d", error); 826 return ebuf; 827 } 828 829 /* 830 * Send a nak packet (error message). 831 * Error code passed in is one of the 832 * standard TFTP codes, or a UNIX errno 833 * offset by 100. 834 */ 835 static void 836 nak(int error) 837 { 838 struct tftphdr *tp; 839 int length; 840 struct errmsg *pe; 841 842 tp = (struct tftphdr *)buf; 843 tp->th_opcode = htons((u_short)ERROR); 844 tp->th_code = htons((u_short)error); 845 for (pe = errmsgs; pe->e_code >= 0; pe++) 846 if (pe->e_code == error) 847 break; 848 if (pe->e_code < 0) { 849 pe->e_msg = strerror(error - 100); 850 tp->th_code = EUNDEF; /* set 'undef' errorcode */ 851 } 852 strcpy(tp->th_msg, pe->e_msg); 853 length = strlen(pe->e_msg); 854 tp->th_msg[length] = '\0'; 855 length += 5; 856 if (send(peer, buf, length, 0) != length) 857 syslog(LOG_ERR, "nak: %m"); 858 } 859 860 /* translate IPv4 mapped IPv6 address to IPv4 address */ 861 static void 862 unmappedaddr(struct sockaddr_in6 *sin6) 863 { 864 struct sockaddr_in *sin4; 865 u_int32_t addr; 866 int port; 867 868 if (sin6->sin6_family != AF_INET6 || 869 !IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)) 870 return; 871 sin4 = (struct sockaddr_in *)sin6; 872 addr = *(u_int32_t *)&sin6->sin6_addr.s6_addr[12]; 873 port = sin6->sin6_port; 874 memset(sin4, 0, sizeof(struct sockaddr_in)); 875 sin4->sin_addr.s_addr = addr; 876 sin4->sin_port = port; 877 sin4->sin_family = AF_INET; 878 sin4->sin_len = sizeof(struct sockaddr_in); 879 } 880 881 /* 882 * Send an oack packet (option acknowledgement). 883 */ 884 static void 885 oack(void) 886 { 887 struct tftphdr *tp, *ap; 888 int size, i, n; 889 char *bp; 890 891 tp = (struct tftphdr *)buf; 892 bp = buf + 2; 893 size = sizeof(buf) - 2; 894 tp->th_opcode = htons((u_short)OACK); 895 for (i = 0; options[i].o_type != NULL; i++) { 896 if (options[i].o_request) { 897 n = snprintf(bp, size, "%s%c%d", options[i].o_type, 898 0, options[i].o_reply); 899 bp += n+1; 900 size -= n+1; 901 if (size < 0) { 902 syslog(LOG_ERR, "oack: buffer overflow"); 903 exit(1); 904 } 905 } 906 } 907 size = bp - buf; 908 ap = (struct tftphdr *)ackbuf; 909 signal(SIGALRM, timer); 910 timeouts = 0; 911 912 (void)setjmp(timeoutbuf); 913 if (send(peer, buf, size, 0) != size) { 914 syslog(LOG_INFO, "oack: %m"); 915 exit(1); 916 } 917 918 for (;;) { 919 alarm(rexmtval); 920 n = recv(peer, ackbuf, sizeof (ackbuf), 0); 921 alarm(0); 922 if (n < 0) { 923 syslog(LOG_ERR, "recv: %m"); 924 exit(1); 925 } 926 ap->th_opcode = ntohs((u_short)ap->th_opcode); 927 ap->th_block = ntohs((u_short)ap->th_block); 928 if (ap->th_opcode == ERROR) 929 exit(1); 930 if (ap->th_opcode == ACK && ap->th_block == 0) 931 break; 932 } 933 } 934