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