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 * @(#) Copyright (c) 1983, 1993 The Regents of the University of California. All rights reserved. 34 * @(#)tftpd.c 8.1 (Berkeley) 6/4/93 35 * $FreeBSD: src/libexec/tftpd/tftpd.c,v 1.15.2.5 2003/04/06 19:42:56 dwmalone Exp $ 36 * $DragonFly: src/libexec/tftpd/tftpd.c,v 1.3 2003/11/20 14:32:17 eirikn Exp $ 37 */ 38 39 /* 40 * Trivial file transfer protocol server. 41 * 42 * This version includes many modifications by Jim Guyton 43 * <guyton@rand-unix>. 44 */ 45 46 #include <sys/param.h> 47 #include <sys/ioctl.h> 48 #include <sys/stat.h> 49 #include <sys/socket.h> 50 #include <sys/types.h> 51 52 #include <netinet/in.h> 53 #include <arpa/tftp.h> 54 #include <arpa/inet.h> 55 56 #include <ctype.h> 57 #include <errno.h> 58 #include <fcntl.h> 59 #include <libutil.h> 60 #include <netdb.h> 61 #include <pwd.h> 62 #include <setjmp.h> 63 #include <signal.h> 64 #include <stdio.h> 65 #include <stdlib.h> 66 #include <string.h> 67 #include <syslog.h> 68 #include <unistd.h> 69 70 #include "tftpsubs.h" 71 72 #define TIMEOUT 5 73 #define MAX_TIMEOUTS 5 74 75 int peer; 76 int rexmtval = TIMEOUT; 77 int max_rexmtval = 2*TIMEOUT; 78 79 #define PKTSIZE SEGSIZE+4 80 char buf[PKTSIZE]; 81 char ackbuf[PKTSIZE]; 82 struct sockaddr_storage from; 83 int fromlen; 84 85 void tftp(struct tftphdr *, int); 86 static void unmappedaddr(struct sockaddr_in6 *); 87 88 /* 89 * Null-terminated directory prefix list for absolute pathname requests and 90 * search list for relative pathname requests. 91 * 92 * MAXDIRS should be at least as large as the number of arguments that 93 * inetd allows (currently 20). 94 */ 95 #define MAXDIRS 20 96 static struct dirlist { 97 const char *name; 98 int len; 99 } dirs[MAXDIRS+1]; 100 static int suppress_naks; 101 static int logging; 102 static int ipchroot; 103 104 static const char *errtomsg(int); 105 static void nak(int); 106 static void oack(void); 107 108 static void timer(int); 109 static void justquit(int); 110 111 int 112 main(int argc, char *argv[]) 113 { 114 struct tftphdr *tp; 115 int n; 116 int ch, on; 117 struct sockaddr_storage me; 118 int len; 119 char *chroot_dir = NULL; 120 struct passwd *nobody; 121 const char *chuser = "nobody"; 122 123 openlog("tftpd", LOG_PID | LOG_NDELAY, LOG_FTP); 124 while ((ch = getopt(argc, argv, "cClns:u:")) != -1) { 125 switch (ch) { 126 case 'c': 127 ipchroot = 1; 128 break; 129 case 'C': 130 ipchroot = 2; 131 break; 132 case 'l': 133 logging = 1; 134 break; 135 case 'n': 136 suppress_naks = 1; 137 break; 138 case 's': 139 chroot_dir = optarg; 140 break; 141 case 'u': 142 chuser = optarg; 143 break; 144 default: 145 syslog(LOG_WARNING, "ignoring unknown option -%c", ch); 146 } 147 } 148 if (optind < argc) { 149 struct dirlist *dirp; 150 151 /* Get list of directory prefixes. Skip relative pathnames. */ 152 for (dirp = dirs; optind < argc && dirp < &dirs[MAXDIRS]; 153 optind++) { 154 if (argv[optind][0] == '/') { 155 dirp->name = argv[optind]; 156 dirp->len = strlen(dirp->name); 157 dirp++; 158 } 159 } 160 } 161 else if (chroot_dir) { 162 dirs->name = "/"; 163 dirs->len = 1; 164 } 165 if (ipchroot && chroot_dir == NULL) { 166 syslog(LOG_ERR, "-c requires -s"); 167 exit(1); 168 } 169 170 on = 1; 171 if (ioctl(0, FIONBIO, &on) < 0) { 172 syslog(LOG_ERR, "ioctl(FIONBIO): %m"); 173 exit(1); 174 } 175 fromlen = sizeof (from); 176 n = recvfrom(0, buf, sizeof (buf), 0, 177 (struct sockaddr *)&from, &fromlen); 178 if (n < 0) { 179 syslog(LOG_ERR, "recvfrom: %m"); 180 exit(1); 181 } 182 /* 183 * Now that we have read the message out of the UDP 184 * socket, we fork and exit. Thus, inetd will go back 185 * to listening to the tftp port, and the next request 186 * to come in will start up a new instance of tftpd. 187 * 188 * We do this so that inetd can run tftpd in "wait" mode. 189 * The problem with tftpd running in "nowait" mode is that 190 * inetd may get one or more successful "selects" on the 191 * tftp port before we do our receive, so more than one 192 * instance of tftpd may be started up. Worse, if tftpd 193 * break before doing the above "recvfrom", inetd would 194 * spawn endless instances, clogging the system. 195 */ 196 { 197 int pid; 198 int i, j; 199 200 for (i = 1; i < 20; i++) { 201 pid = fork(); 202 if (pid < 0) { 203 sleep(i); 204 /* 205 * flush out to most recently sent request. 206 * 207 * This may drop some request, but those 208 * will be resent by the clients when 209 * they timeout. The positive effect of 210 * this flush is to (try to) prevent more 211 * than one tftpd being started up to service 212 * a single request from a single client. 213 */ 214 j = sizeof from; 215 i = recvfrom(0, buf, sizeof (buf), 0, 216 (struct sockaddr *)&from, &j); 217 if (i > 0) { 218 n = i; 219 fromlen = j; 220 } 221 } else { 222 break; 223 } 224 } 225 if (pid < 0) { 226 syslog(LOG_ERR, "fork: %m"); 227 exit(1); 228 } else if (pid != 0) { 229 exit(0); 230 } 231 } 232 233 /* 234 * Since we exit here, we should do that only after the above 235 * recvfrom to keep inetd from constantly forking should there 236 * be a problem. See the above comment about system clogging. 237 */ 238 if (chroot_dir) { 239 if (ipchroot) { 240 char *tempchroot; 241 struct stat sb; 242 int statret; 243 struct sockaddr_storage ss; 244 char hbuf[NI_MAXHOST]; 245 246 memcpy(&ss, &from, from.ss_len); 247 unmappedaddr((struct sockaddr_in6 *)&ss); 248 getnameinfo((struct sockaddr *)&ss, ss.ss_len, 249 hbuf, sizeof(hbuf), NULL, 0, 250 NI_NUMERICHOST | NI_WITHSCOPEID); 251 asprintf(&tempchroot, "%s/%s", chroot_dir, hbuf); 252 statret = stat(tempchroot, &sb); 253 if ((sb.st_mode & S_IFDIR) && 254 (statret == 0 || (statret == -1 && ipchroot == 1))) 255 chroot_dir = tempchroot; 256 } 257 /* Must get this before chroot because /etc might go away */ 258 if ((nobody = getpwnam(chuser)) == NULL) { 259 syslog(LOG_ERR, "%s: no such user", chuser); 260 exit(1); 261 } 262 if (chroot(chroot_dir)) { 263 syslog(LOG_ERR, "chroot: %s: %m", chroot_dir); 264 exit(1); 265 } 266 chdir( "/" ); 267 setuid(nobody->pw_uid); 268 setgroups(1, &nobody->pw_gid); 269 } 270 271 len = sizeof(me); 272 if (getsockname(0, (struct sockaddr *)&me, &len) == 0) { 273 switch (me.ss_family) { 274 case AF_INET: 275 ((struct sockaddr_in *)&me)->sin_port = 0; 276 break; 277 case AF_INET6: 278 ((struct sockaddr_in6 *)&me)->sin6_port = 0; 279 break; 280 default: 281 /* unsupported */ 282 break; 283 } 284 } else { 285 memset(&me, 0, sizeof(me)); 286 me.ss_family = from.ss_family; 287 me.ss_len = from.ss_len; 288 } 289 alarm(0); 290 close(0); 291 close(1); 292 peer = socket(from.ss_family, SOCK_DGRAM, 0); 293 if (peer < 0) { 294 syslog(LOG_ERR, "socket: %m"); 295 exit(1); 296 } 297 if (bind(peer, (struct sockaddr *)&me, me.ss_len) < 0) { 298 syslog(LOG_ERR, "bind: %m"); 299 exit(1); 300 } 301 if (connect(peer, (struct sockaddr *)&from, from.ss_len) < 0) { 302 syslog(LOG_ERR, "connect: %m"); 303 exit(1); 304 } 305 tp = (struct tftphdr *)buf; 306 tp->th_opcode = ntohs(tp->th_opcode); 307 if (tp->th_opcode == RRQ || tp->th_opcode == WRQ) 308 tftp(tp, n); 309 exit(1); 310 } 311 312 struct formats; 313 int validate_access(char **, int); 314 void xmitfile(struct formats *); 315 void recvfile(struct formats *); 316 317 struct formats { 318 const char *f_mode; 319 int (*f_validate)(char **, int); 320 void (*f_send)(struct formats *); 321 void (*f_recv)(struct formats *); 322 int f_convert; 323 } formats[] = { 324 { "netascii", validate_access, xmitfile, recvfile, 1 }, 325 { "octet", validate_access, xmitfile, recvfile, 0 }, 326 #ifdef notdef 327 { "mail", validate_user, sendmail, recvmail, 1 }, 328 #endif 329 { 0, NULL, NULL, NULL, 0 } 330 }; 331 332 struct options { 333 const char *o_type; 334 char *o_request; 335 int o_reply; /* turn into union if need be */ 336 } options[] = { 337 { "tsize", NULL, 0 }, /* OPT_TSIZE */ 338 { "timeout", NULL, 0 }, /* OPT_TIMEOUT */ 339 { NULL, NULL, 0 } 340 }; 341 342 enum opt_enum { 343 OPT_TSIZE = 0, 344 OPT_TIMEOUT, 345 }; 346 347 /* 348 * Handle initial connection protocol. 349 */ 350 void 351 tftp(struct tftphdr *tp, int size) 352 { 353 char *cp; 354 size_t i; 355 int first = 1, has_options = 0, ecode; 356 struct formats *pf; 357 char *filename, *mode = NULL, *option, *ccp; 358 char fnbuf[MAXPATHLEN]; 359 360 cp = tp->th_stuff; 361 again: 362 while (cp < buf + size) { 363 if (*cp == '\0') 364 break; 365 cp++; 366 } 367 if (*cp != '\0') { 368 nak(EBADOP); 369 exit(1); 370 } 371 i = cp - tp->th_stuff; 372 if (i >= sizeof(fnbuf)) { 373 nak(EBADOP); 374 exit(1); 375 } 376 memcpy(fnbuf, tp->th_stuff, i); 377 fnbuf[i] = '\0'; 378 filename = fnbuf; 379 if (first) { 380 mode = ++cp; 381 first = 0; 382 goto again; 383 } 384 for (cp = mode; *cp; cp++) 385 if (isupper(*cp)) 386 *cp = tolower(*cp); 387 for (pf = formats; pf->f_mode; pf++) 388 if (strcmp(pf->f_mode, mode) == 0) 389 break; 390 if (pf->f_mode == 0) { 391 nak(EBADOP); 392 exit(1); 393 } 394 while (++cp < buf + size) { 395 for (i = 2, ccp = cp; i > 0; ccp++) { 396 if (ccp >= buf + size) { 397 /* 398 * Don't reject the request, just stop trying 399 * to parse the option and get on with it. 400 * Some Apple OpenFirmware versions have 401 * trailing garbage on the end of otherwise 402 * valid requests. 403 */ 404 goto option_fail; 405 } else if (*ccp == '\0') 406 i--; 407 } 408 for (option = cp; *cp; cp++) 409 if (isupper(*cp)) 410 *cp = tolower(*cp); 411 for (i = 0; options[i].o_type != NULL; i++) 412 if (strcmp(option, options[i].o_type) == 0) { 413 options[i].o_request = ++cp; 414 has_options = 1; 415 } 416 cp = ccp-1; 417 } 418 419 option_fail: 420 if (options[OPT_TIMEOUT].o_request) { 421 int to = atoi(options[OPT_TIMEOUT].o_request); 422 if (to < 1 || to > 255) { 423 nak(EBADOP); 424 exit(1); 425 } 426 else if (to <= max_rexmtval) 427 options[OPT_TIMEOUT].o_reply = rexmtval = to; 428 else 429 options[OPT_TIMEOUT].o_request = NULL; 430 } 431 432 ecode = (*pf->f_validate)(&filename, tp->th_opcode); 433 if (has_options) 434 oack(); 435 if (logging) { 436 char hbuf[NI_MAXHOST]; 437 438 getnameinfo((struct sockaddr *)&from, from.ss_len, 439 hbuf, sizeof(hbuf), NULL, 0, 440 NI_WITHSCOPEID); 441 syslog(LOG_INFO, "%s: %s request for %s: %s", hbuf, 442 tp->th_opcode == WRQ ? "write" : "read", 443 filename, errtomsg(ecode)); 444 } 445 if (ecode) { 446 /* 447 * Avoid storms of naks to a RRQ broadcast for a relative 448 * bootfile pathname from a diskless Sun. 449 */ 450 if (suppress_naks && *filename != '/' && ecode == ENOTFOUND) 451 exit(0); 452 nak(ecode); 453 exit(1); 454 } 455 if (tp->th_opcode == WRQ) 456 (*pf->f_recv)(pf); 457 else 458 (*pf->f_send)(pf); 459 exit(0); 460 } 461 462 463 FILE *file; 464 465 /* 466 * Validate file access. Since we 467 * have no uid or gid, for now require 468 * file to exist and be publicly 469 * readable/writable. 470 * If we were invoked with arguments 471 * from inetd then the file must also be 472 * in one of the given directory prefixes. 473 * Note also, full path name must be 474 * given as we have no login directory. 475 */ 476 int 477 validate_access(char **filep, int mode) 478 { 479 struct stat stbuf; 480 int fd; 481 struct dirlist *dirp; 482 static char pathname[MAXPATHLEN]; 483 char *filename = *filep; 484 485 /* 486 * Prevent tricksters from getting around the directory restrictions 487 */ 488 if (strstr(filename, "/../")) 489 return (EACCESS); 490 491 if (*filename == '/') { 492 /* 493 * Allow the request if it's in one of the approved locations. 494 * Special case: check the null prefix ("/") by looking 495 * for length = 1 and relying on the arg. processing that 496 * it's a /. 497 */ 498 for (dirp = dirs; dirp->name != NULL; dirp++) { 499 if (dirp->len == 1 || 500 (!strncmp(filename, dirp->name, dirp->len) && 501 filename[dirp->len] == '/')) 502 break; 503 } 504 /* If directory list is empty, allow access to any file */ 505 if (dirp->name == NULL && dirp != dirs) 506 return (EACCESS); 507 if (stat(filename, &stbuf) < 0) 508 return (errno == ENOENT ? ENOTFOUND : EACCESS); 509 if ((stbuf.st_mode & S_IFMT) != S_IFREG) 510 return (ENOTFOUND); 511 if (mode == RRQ) { 512 if ((stbuf.st_mode & S_IROTH) == 0) 513 return (EACCESS); 514 } else { 515 if ((stbuf.st_mode & S_IWOTH) == 0) 516 return (EACCESS); 517 } 518 } else { 519 int err; 520 521 /* 522 * Relative file name: search the approved locations for it. 523 * Don't allow write requests that avoid directory 524 * restrictions. 525 */ 526 527 if (!strncmp(filename, "../", 3)) 528 return (EACCESS); 529 530 /* 531 * If the file exists in one of the directories and isn't 532 * readable, continue looking. However, change the error code 533 * to give an indication that the file exists. 534 */ 535 err = ENOTFOUND; 536 for (dirp = dirs; dirp->name != NULL; dirp++) { 537 snprintf(pathname, sizeof(pathname), "%s/%s", 538 dirp->name, filename); 539 if (stat(pathname, &stbuf) == 0 && 540 (stbuf.st_mode & S_IFMT) == S_IFREG) { 541 if ((stbuf.st_mode & S_IROTH) != 0) { 542 break; 543 } 544 err = EACCESS; 545 } 546 } 547 if (dirp->name == NULL) 548 return (err); 549 *filep = filename = pathname; 550 } 551 if (options[OPT_TSIZE].o_request) { 552 if (mode == RRQ) 553 options[OPT_TSIZE].o_reply = stbuf.st_size; 554 else 555 /* XXX Allows writes of all sizes. */ 556 options[OPT_TSIZE].o_reply = 557 atoi(options[OPT_TSIZE].o_request); 558 } 559 fd = open(filename, mode == RRQ ? O_RDONLY : O_WRONLY|O_TRUNC); 560 if (fd < 0) 561 return (errno + 100); 562 file = fdopen(fd, (mode == RRQ)? "r":"w"); 563 if (file == NULL) { 564 return errno+100; 565 } 566 return (0); 567 } 568 569 int timeouts; 570 jmp_buf timeoutbuf; 571 572 void 573 timer(int sig __unused) 574 { 575 if (++timeouts > MAX_TIMEOUTS) 576 exit(1); 577 longjmp(timeoutbuf, 1); 578 } 579 580 /* 581 * Send the requested file. 582 */ 583 void 584 xmitfile(struct formats *pf) 585 { 586 struct tftphdr *dp; 587 struct tftphdr *ap; /* ack packet */ 588 int size, n; 589 volatile unsigned short block; 590 591 signal(SIGALRM, timer); 592 dp = r_init(); 593 ap = (struct tftphdr *)ackbuf; 594 block = 1; 595 do { 596 size = readit(file, &dp, pf->f_convert); 597 if (size < 0) { 598 nak(errno + 100); 599 goto abort; 600 } 601 dp->th_opcode = htons((u_short)DATA); 602 dp->th_block = htons((u_short)block); 603 timeouts = 0; 604 (void)setjmp(timeoutbuf); 605 606 send_data: 607 { 608 int i, t = 1; 609 for (i = 0; ; i++){ 610 if (send(peer, dp, size + 4, 0) != size + 4) { 611 sleep(t); 612 t = (t < 32) ? t<< 1 : t; 613 if (i >= 12) { 614 syslog(LOG_ERR, "write: %m"); 615 goto abort; 616 } 617 } 618 break; 619 } 620 } 621 read_ahead(file, pf->f_convert); 622 for ( ; ; ) { 623 alarm(rexmtval); /* read the ack */ 624 n = recv(peer, ackbuf, sizeof (ackbuf), 0); 625 alarm(0); 626 if (n < 0) { 627 syslog(LOG_ERR, "read: %m"); 628 goto abort; 629 } 630 ap->th_opcode = ntohs((u_short)ap->th_opcode); 631 ap->th_block = ntohs((u_short)ap->th_block); 632 633 if (ap->th_opcode == ERROR) 634 goto abort; 635 636 if (ap->th_opcode == ACK) { 637 if (ap->th_block == block) 638 break; 639 /* Re-synchronize with the other side */ 640 (void) synchnet(peer); 641 if (ap->th_block == (block -1)) 642 goto send_data; 643 } 644 645 } 646 block++; 647 } while (size == SEGSIZE); 648 abort: 649 (void) fclose(file); 650 } 651 652 void 653 justquit(int sig __unused) 654 { 655 exit(0); 656 } 657 658 659 /* 660 * Receive a file. 661 */ 662 void 663 recvfile(struct formats *pf) 664 { 665 struct tftphdr *dp; 666 struct tftphdr *ap; /* ack buffer */ 667 int n, size; 668 volatile unsigned short block; 669 670 signal(SIGALRM, timer); 671 dp = w_init(); 672 ap = (struct tftphdr *)ackbuf; 673 block = 0; 674 do { 675 timeouts = 0; 676 ap->th_opcode = htons((u_short)ACK); 677 ap->th_block = htons((u_short)block); 678 block++; 679 (void) setjmp(timeoutbuf); 680 send_ack: 681 if (send(peer, ackbuf, 4, 0) != 4) { 682 syslog(LOG_ERR, "write: %m"); 683 goto abort; 684 } 685 write_behind(file, pf->f_convert); 686 for ( ; ; ) { 687 alarm(rexmtval); 688 n = recv(peer, dp, PKTSIZE, 0); 689 alarm(0); 690 if (n < 0) { /* really? */ 691 syslog(LOG_ERR, "read: %m"); 692 goto abort; 693 } 694 dp->th_opcode = ntohs((u_short)dp->th_opcode); 695 dp->th_block = ntohs((u_short)dp->th_block); 696 if (dp->th_opcode == ERROR) 697 goto abort; 698 if (dp->th_opcode == DATA) { 699 if (dp->th_block == block) { 700 break; /* normal */ 701 } 702 /* Re-synchronize with the other side */ 703 (void) synchnet(peer); 704 if (dp->th_block == (block-1)) 705 goto send_ack; /* rexmit */ 706 } 707 } 708 /* size = write(file, dp->th_data, n - 4); */ 709 size = writeit(file, &dp, n - 4, pf->f_convert); 710 if (size != (n-4)) { /* ahem */ 711 if (size < 0) nak(errno + 100); 712 else nak(ENOSPACE); 713 goto abort; 714 } 715 } while (size == SEGSIZE); 716 write_behind(file, pf->f_convert); 717 (void) fclose(file); /* close data file */ 718 719 ap->th_opcode = htons((u_short)ACK); /* send the "final" ack */ 720 ap->th_block = htons((u_short)(block)); 721 (void) send(peer, ackbuf, 4, 0); 722 723 signal(SIGALRM, justquit); /* just quit on timeout */ 724 alarm(rexmtval); 725 n = recv(peer, buf, sizeof (buf), 0); /* normally times out and quits */ 726 alarm(0); 727 if (n >= 4 && /* if read some data */ 728 dp->th_opcode == DATA && /* and got a data block */ 729 block == dp->th_block) { /* then my last ack was lost */ 730 (void) send(peer, ackbuf, 4, 0); /* resend final ack */ 731 } 732 abort: 733 return; 734 } 735 736 struct errmsg { 737 int e_code; 738 const char *e_msg; 739 } errmsgs[] = { 740 { EUNDEF, "Undefined error code" }, 741 { ENOTFOUND, "File not found" }, 742 { EACCESS, "Access violation" }, 743 { ENOSPACE, "Disk full or allocation exceeded" }, 744 { EBADOP, "Illegal TFTP operation" }, 745 { EBADID, "Unknown transfer ID" }, 746 { EEXISTS, "File already exists" }, 747 { ENOUSER, "No such user" }, 748 { EOPTNEG, "Option negotiation" }, 749 { -1, 0 } 750 }; 751 752 static const char * 753 errtomsg(int error) 754 { 755 static char ebuf[20]; 756 struct errmsg *pe; 757 if (error == 0) 758 return "success"; 759 for (pe = errmsgs; pe->e_code >= 0; pe++) 760 if (pe->e_code == error) 761 return pe->e_msg; 762 snprintf(ebuf, sizeof(buf), "error %d", error); 763 return ebuf; 764 } 765 766 /* 767 * Send a nak packet (error message). 768 * Error code passed in is one of the 769 * standard TFTP codes, or a UNIX errno 770 * offset by 100. 771 */ 772 static void 773 nak(int error) 774 { 775 struct tftphdr *tp; 776 int length; 777 struct errmsg *pe; 778 779 tp = (struct tftphdr *)buf; 780 tp->th_opcode = htons((u_short)ERROR); 781 tp->th_code = htons((u_short)error); 782 for (pe = errmsgs; pe->e_code >= 0; pe++) 783 if (pe->e_code == error) 784 break; 785 if (pe->e_code < 0) { 786 pe->e_msg = strerror(error - 100); 787 tp->th_code = EUNDEF; /* set 'undef' errorcode */ 788 } 789 strcpy(tp->th_msg, pe->e_msg); 790 length = strlen(pe->e_msg); 791 tp->th_msg[length] = '\0'; 792 length += 5; 793 if (send(peer, buf, length, 0) != length) 794 syslog(LOG_ERR, "nak: %m"); 795 } 796 797 /* translate IPv4 mapped IPv6 address to IPv4 address */ 798 static void 799 unmappedaddr(struct sockaddr_in6 *sin6) 800 { 801 struct sockaddr_in *sin4; 802 u_int32_t addr; 803 int port; 804 805 if (sin6->sin6_family != AF_INET6 || 806 !IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)) 807 return; 808 sin4 = (struct sockaddr_in *)sin6; 809 addr = *(u_int32_t *)&sin6->sin6_addr.s6_addr[12]; 810 port = sin6->sin6_port; 811 memset(sin4, 0, sizeof(struct sockaddr_in)); 812 sin4->sin_addr.s_addr = addr; 813 sin4->sin_port = port; 814 sin4->sin_family = AF_INET; 815 sin4->sin_len = sizeof(struct sockaddr_in); 816 } 817 818 /* 819 * Send an oack packet (option acknowledgement). 820 */ 821 static void 822 oack(void) 823 { 824 struct tftphdr *tp, *ap; 825 int size, i, n; 826 char *bp; 827 828 tp = (struct tftphdr *)buf; 829 bp = buf + 2; 830 size = sizeof(buf) - 2; 831 tp->th_opcode = htons((u_short)OACK); 832 for (i = 0; options[i].o_type != NULL; i++) { 833 if (options[i].o_request) { 834 n = snprintf(bp, size, "%s%c%d", options[i].o_type, 835 0, options[i].o_reply); 836 bp += n+1; 837 size -= n+1; 838 if (size < 0) { 839 syslog(LOG_ERR, "oack: buffer overflow"); 840 exit(1); 841 } 842 } 843 } 844 size = bp - buf; 845 ap = (struct tftphdr *)ackbuf; 846 signal(SIGALRM, timer); 847 timeouts = 0; 848 849 (void)setjmp(timeoutbuf); 850 if (send(peer, buf, size, 0) != size) { 851 syslog(LOG_INFO, "oack: %m"); 852 exit(1); 853 } 854 855 for (;;) { 856 alarm(rexmtval); 857 n = recv(peer, ackbuf, sizeof (ackbuf), 0); 858 alarm(0); 859 if (n < 0) { 860 syslog(LOG_ERR, "recv: %m"); 861 exit(1); 862 } 863 ap->th_opcode = ntohs((u_short)ap->th_opcode); 864 ap->th_block = ntohs((u_short)ap->th_block); 865 if (ap->th_opcode == ERROR) 866 exit(1); 867 if (ap->th_opcode == ACK && ap->th_block == 0) 868 break; 869 } 870 } 871