1 #ifndef lint 2 static char sccsid[] = "@(#)ftpd.c 4.13 (Berkeley) 01/23/83"; 3 #endif 4 5 /* 6 * FTP server. 7 */ 8 #include <sys/param.h> 9 #include <sys/stat.h> 10 #include <sys/ioctl.h> 11 #include <sys/socket.h> 12 13 #include <netinet/in.h> 14 15 #include <stdio.h> 16 #include <signal.h> 17 #include <wait.h> 18 #include <pwd.h> 19 #include <setjmp.h> 20 #include <netdb.h> 21 #include <errno.h> 22 23 #include "ftp.h" 24 25 extern int errno; 26 extern char *sys_errlist[]; 27 extern char *crypt(); 28 extern char version[]; 29 extern char *home; /* pointer to home directory for glob */ 30 extern FILE *popen(), *fopen(); 31 extern int pclose(), fclose(); 32 33 struct sockaddr_in ctrl_addr; 34 struct sockaddr_in data_source; 35 struct sockaddr_in data_dest; 36 struct sockaddr_in his_addr; 37 38 struct hostent *hp; 39 40 int data; 41 jmp_buf errcatch; 42 int logged_in; 43 struct passwd *pw; 44 int debug; 45 int logging = 1; 46 int guest; 47 int type; 48 int form; 49 int stru; /* avoid C keyword */ 50 int mode; 51 int usedefault = 1; /* for data transfers */ 52 char hostname[32]; 53 char *remotehost; 54 struct servent *sp; 55 56 int lostconn(); 57 int reapchild(); 58 FILE *getdatasock(), *dataconn(); 59 char *ntoa(); 60 61 main(argc, argv) 62 int argc; 63 char *argv[]; 64 { 65 int ctrl, s, options = 0; 66 char *cp; 67 68 sp = getservbyname("ftp", "tcp"); 69 if (sp == 0) { 70 fprintf(stderr, "ftpd: fpt/tcp: unknown service\n"); 71 exit(1); 72 } 73 ctrl_addr.sin_port = sp->s_port; 74 data_source.sin_port = htons(ntohs(sp->s_port) - 1); 75 signal(SIGPIPE, lostconn); 76 debug = 0; 77 argc--, argv++; 78 while (argc > 0 && *argv[0] == '-') { 79 for (cp = &argv[0][1]; *cp; cp++) switch (*cp) { 80 81 case 'd': 82 debug = 1; 83 options |= SO_DEBUG; 84 break; 85 86 default: 87 fprintf(stderr, "Unknown flag -%c ignored.\n", cp); 88 break; 89 } 90 argc--, argv++; 91 } 92 #ifndef DEBUG 93 if (fork()) 94 exit(0); 95 for (s = 0; s < 10; s++) 96 (void) close(s); 97 (void) open("/dev/null", 0); 98 (void) dup2(0, 1); 99 { int tt = open("/dev/tty", 2); 100 if (tt > 0) { 101 ioctl(tt, TIOCNOTTY, 0); 102 close(tt); 103 } 104 } 105 #endif 106 while ((s = socket(AF_INET, SOCK_STREAM, 0, 0)) < 0) { 107 perror("ftpd: socket"); 108 sleep(5); 109 } 110 if (options & SO_DEBUG) 111 if (setsockopt(s, SOL_SOCKET, SO_DEBUG, 0, 0) < 0) 112 perror("ftpd: setsockopt (SO_DEBUG)"); 113 #ifdef notdef 114 if (setsockopt(s, SOL_SOCKET, SO_KEEPALIVE, 0, 0) < 0) 115 perror("ftpd: setsockopt (SO_KEEPALIVE)"); 116 #endif 117 while (bind(s, &ctrl_addr, sizeof (ctrl_addr), 0) < 0) { 118 perror("ftpd: bind"); 119 sleep(5); 120 } 121 sigset(SIGCHLD, reapchild); 122 listen(s, 10); 123 for (;;) { 124 int hisaddrlen = sizeof (his_addr); 125 126 ctrl = accept(s, &his_addr, &hisaddrlen, 0); 127 if (ctrl < 0) { 128 if (errno == EINTR) 129 continue; 130 perror("ftpd: accept"); 131 continue; 132 } 133 if (fork() == 0) { 134 if (logging) 135 dolog(&his_addr); 136 close(s); 137 dup2(ctrl, 0), close(ctrl), dup2(0, 1); 138 /* do telnet option negotiation here */ 139 /* 140 * Set up default state 141 */ 142 logged_in = 0; 143 data = -1; 144 type = TYPE_A; 145 form = FORM_N; 146 stru = STRU_F; 147 mode = MODE_S; 148 gethostname(hostname, sizeof (hostname)); 149 reply(220, "%s FTP server (%s) ready.", 150 hostname, version); 151 for (;;) { 152 setjmp(errcatch); 153 yyparse(); 154 } 155 } 156 close(ctrl); 157 } 158 } 159 160 reapchild() 161 { 162 union wait status; 163 164 while (wait3(&status, WNOHANG, 0) > 0) 165 ; 166 } 167 168 lostconn() 169 { 170 171 fatal("Connection closed."); 172 } 173 174 pass(passwd) 175 char *passwd; 176 { 177 char *xpasswd, *savestr(); 178 static struct passwd save; 179 180 if (logged_in || pw == NULL) { 181 reply(503, "Login with USER first."); 182 return; 183 } 184 if (!guest) { /* "ftp" is only account allowed no password */ 185 xpasswd = crypt(passwd, pw->pw_passwd); 186 if (strcmp(xpasswd, pw->pw_passwd) != 0) { 187 reply(530, "Login incorrect."); 188 pw = NULL; 189 return; 190 } 191 } 192 setegid(pw->pw_gid); 193 initgroups(pw->pw_name, pw->pw_gid); 194 if (chdir(pw->pw_dir)) { 195 reply(550, "User %s: can't change directory to $s.", 196 pw->pw_name, pw->pw_dir); 197 goto bad; 198 } 199 if (guest && chroot(pw->pw_dir) < 0) { 200 reply(550, "Can't set guest privileges."); 201 goto bad; 202 } 203 if (!guest) 204 reply(230, "User %s logged in.", pw->pw_name); 205 else 206 reply(230, "Guest login ok, access restrictions apply."); 207 logged_in = 1; 208 seteuid(pw->pw_uid); 209 /* 210 * Save everything so globbing doesn't 211 * clobber the fields. 212 */ 213 save = *pw; 214 save.pw_name = savestr(pw->pw_name); 215 save.pw_passwd = savestr(pw->pw_passwd); 216 save.pw_comment = savestr(pw->pw_comment); 217 save.pw_gecos = savestr(pw->pw_gecos, &save.pw_gecos); 218 save.pw_dir = savestr(pw->pw_dir); 219 save.pw_shell = savestr(pw->pw_shell); 220 pw = &save; 221 home = pw->pw_dir; /* home dir for globbing */ 222 return; 223 bad: 224 seteuid(0); 225 pw = NULL; 226 } 227 228 char * 229 savestr(s) 230 char *s; 231 { 232 char *malloc(); 233 char *new = malloc(strlen(s) + 1); 234 235 if (new != NULL) 236 strcpy(new, s); 237 return(new); 238 } 239 240 retrieve(cmd, name) 241 char *cmd, *name; 242 { 243 FILE *fin, *dout; 244 struct stat st; 245 int (*closefunc)(); 246 247 if (cmd == 0) { 248 #ifdef notdef 249 /* no remote command execution -- it's a security hole */ 250 if (*name == '!') 251 fin = popen(name + 1, "r"), closefunc = pclose; 252 else 253 #endif 254 fin = fopen(name, "r"), closefunc = fclose; 255 } else { 256 char line[BUFSIZ]; 257 258 sprintf(line, cmd, name), name = line; 259 fin = popen(line, "r"), closefunc = pclose; 260 } 261 if (fin == NULL) { 262 reply(550, "%s: %s.", name, sys_errlist[errno]); 263 return; 264 } 265 st.st_size = 0; 266 if (cmd == 0 && 267 (stat(name, &st) < 0 || (st.st_mode&S_IFMT) != S_IFREG)) { 268 reply(550, "%s: not a plain file.", name); 269 goto done; 270 } 271 dout = dataconn(name, st.st_size, "w"); 272 if (dout == NULL) 273 goto done; 274 if (send_data(fin, dout) || ferror(dout)) 275 reply(550, "%s: %s.", name, sys_errlist[errno]); 276 else 277 reply(226, "Transfer complete."); 278 fclose(dout), data = -1; 279 done: 280 (*closefunc)(fin); 281 } 282 283 store(name, mode) 284 char *name, *mode; 285 { 286 FILE *fout, *din; 287 int (*closefunc)(), dochown = 0; 288 289 #ifdef notdef 290 /* no remote command execution -- it's a security hole */ 291 if (name[0] == '!') 292 fout = popen(&name[1], "w"), closefunc = pclose; 293 else 294 #endif 295 { 296 struct stat st; 297 298 if (stat(name, &st) < 0) 299 dochown++; 300 fout = fopen(name, mode), closefunc = fclose; 301 } 302 if (fout == NULL) { 303 reply(550, "%s: %s.", name, sys_errlist[errno]); 304 return; 305 } 306 din = dataconn(name, -1, "r"); 307 if (din == NULL) 308 goto done; 309 if (receive_data(din, fout) || ferror(fout)) 310 reply(550, "%s: %s.", name, sys_errlist[errno]); 311 else 312 reply(226, "Transfer complete."); 313 fclose(din), data = -1; 314 done: 315 if (dochown) 316 (void) chown(name, pw->pw_uid, -1); 317 (*closefunc)(fout); 318 } 319 320 FILE * 321 getdatasock(mode) 322 char *mode; 323 { 324 int s; 325 326 if (data >= 0) 327 return (fdopen(data, mode)); 328 s = socket(AF_INET, SOCK_STREAM, 0, 0); 329 if (s < 0) 330 return (NULL); 331 seteuid(0); 332 if (setsockopt(s, SOL_SOCKET, SO_REUSEADDR, 0, 0) < 0) 333 goto bad; 334 if (bind(s, &data_source, sizeof (data_source), 0) < 0) 335 goto bad; 336 seteuid(pw->pw_uid); 337 return (fdopen(s, mode)); 338 bad: 339 seteuid(pw->pw_uid); 340 close(s); 341 return (NULL); 342 } 343 344 FILE * 345 dataconn(name, size, mode) 346 char *name; 347 int size; 348 char *mode; 349 { 350 char sizebuf[32]; 351 FILE *file; 352 353 if (size >= 0) 354 sprintf(sizebuf, " (%d bytes)", size); 355 else 356 (void) strcpy(sizebuf, ""); 357 if (data >= 0) { 358 reply(125, "Using existing data connection for %s%s.", 359 name, sizebuf); 360 usedefault = 1; 361 return (fdopen(data, mode)); 362 } 363 if (usedefault) 364 data_dest = his_addr; 365 usedefault = 1; 366 file = getdatasock(mode); 367 if (file == NULL) { 368 reply(425, "Can't create data socket (%s,%d): %s.", 369 ntoa(data_source.sin_addr), 370 ntohs(data_source.sin_port), 371 sys_errlist[errno]); 372 return (NULL); 373 } 374 reply(150, "Opening data connection for %s (%s,%d)%s.", 375 name, ntoa(data_dest.sin_addr.s_addr), 376 ntohs(data_dest.sin_port), sizebuf); 377 data = fileno(file); 378 if (connect(data, &data_dest, sizeof (data_dest), 0) < 0) { 379 reply(425, "Can't build data connection: %s.", 380 sys_errlist[errno]); 381 (void) fclose(file); 382 data = -1; 383 return (NULL); 384 } 385 return (file); 386 } 387 388 /* 389 * Tranfer the contents of "instr" to 390 * "outstr" peer using the appropriate 391 * encapulation of the date subject 392 * to Mode, Structure, and Type. 393 * 394 * NB: Form isn't handled. 395 */ 396 send_data(instr, outstr) 397 FILE *instr, *outstr; 398 { 399 register int c; 400 int netfd, filefd, cnt; 401 char buf[BUFSIZ]; 402 403 switch (type) { 404 405 case TYPE_A: 406 while ((c = getc(instr)) != EOF) { 407 if (c == '\n') 408 putc('\r', outstr); 409 if (putc(c, outstr) == EOF) 410 return (1); 411 } 412 return (0); 413 414 case TYPE_I: 415 case TYPE_L: 416 netfd = fileno(outstr); 417 filefd = fileno(instr); 418 419 while ((cnt = read(filefd, buf, sizeof (buf))) > 0) 420 if (write(netfd, buf, cnt) < 0) 421 return (1); 422 return (cnt < 0); 423 } 424 reply(504,"Unimplemented TYPE %d in send_data", type); 425 return (1); 426 } 427 428 /* 429 * Transfer data from peer to 430 * "outstr" using the appropriate 431 * encapulation of the data subject 432 * to Mode, Structure, and Type. 433 * 434 * N.B.: Form isn't handled. 435 */ 436 receive_data(instr, outstr) 437 FILE *instr, *outstr; 438 { 439 register int c; 440 int cr, escape, eof; 441 int netfd, filefd, cnt; 442 char buf[BUFSIZ]; 443 444 445 switch (type) { 446 447 case TYPE_I: 448 case TYPE_L: 449 netfd = fileno(instr); 450 netfd = fileno(outstr); 451 while ((cnt = read(netfd, buf, sizeof buf)) > 0) 452 if (write(filefd, buf, cnt) < 0) 453 return (1); 454 return (cnt < 0); 455 456 case TYPE_E: 457 reply(504, "TYPE E not implemented."); 458 return (1); 459 460 case TYPE_A: 461 cr = 0; 462 while ((c = getc(instr)) != EOF) { 463 if (cr) { 464 if (c != '\r' && c != '\n') 465 putc('\r', outstr); 466 putc(c, outstr); 467 cr = c == '\r'; 468 continue; 469 } 470 if (c == '\r') { 471 cr = 1; 472 continue; 473 } 474 putc(c, outstr); 475 } 476 if (cr) 477 putc('\r', outstr); 478 return (0); 479 } 480 fatal("Unknown type in receive_data."); 481 /*NOTREACHED*/ 482 } 483 484 fatal(s) 485 char *s; 486 { 487 reply(451, "Error in server: %s\n", s); 488 reply(221, "Closing connection due to server error."); 489 exit(0); 490 } 491 492 reply(n, s, args) 493 int n; 494 char *s; 495 { 496 497 printf("%d ", n); 498 _doprnt(s, &args, stdout); 499 printf("\r\n"); 500 fflush(stdout); 501 if (debug) { 502 fprintf(stderr, "<--- %d ", n); 503 _doprnt(s, &args, stderr); 504 fprintf(stderr, "\n"); 505 fflush(stderr); 506 } 507 } 508 509 lreply(n, s, args) 510 int n; 511 char *s; 512 { 513 printf("%d-", n); 514 _doprnt(s, &args, stdout); 515 printf("\r\n"); 516 fflush(stdout); 517 if (debug) { 518 fprintf(stderr, "<--- %d-", n); 519 _doprnt(s, &args, stderr); 520 fprintf(stderr, "\n"); 521 } 522 } 523 524 replystr(s) 525 char *s; 526 { 527 printf("%s\r\n", s); 528 fflush(stdout); 529 if (debug) 530 fprintf(stderr, "<--- %s\n", s); 531 } 532 533 ack(s) 534 char *s; 535 { 536 reply(200, "%s command okay.", s); 537 } 538 539 nack(s) 540 char *s; 541 { 542 reply(502, "%s command not implemented.", s); 543 } 544 545 yyerror() 546 { 547 reply(500, "Command not understood."); 548 } 549 550 delete(name) 551 char *name; 552 { 553 struct stat st; 554 555 if (stat(name, &st) < 0) { 556 reply(550, "%s: %s.", name, sys_errlist[errno]); 557 return; 558 } 559 if ((st.st_mode&S_IFMT) == S_IFDIR) { 560 if (rmdir(name) < 0) { 561 reply(550, "%s: %s.", name, sys_errlist[errno]); 562 return; 563 } 564 goto done; 565 } 566 if (unlink(name) < 0) { 567 reply(550, "%s: %s.", name, sys_errlist[errno]); 568 return; 569 } 570 done: 571 ack("DELE"); 572 } 573 574 cwd(path) 575 char *path; 576 { 577 578 if (chdir(path) < 0) { 579 reply(550, "%s: %s.", path, sys_errlist[errno]); 580 return; 581 } 582 ack("CWD"); 583 } 584 585 makedir(name) 586 char *name; 587 { 588 struct stat st; 589 int dochown = stat(name, &st) < 0; 590 591 if (mkdir(name, 0777) < 0) { 592 reply(550, "%s: %s.", name, sys_errlist[errno]); 593 return; 594 } 595 if (dochown) 596 (void) chown(name, pw->pw_uid, -1); 597 ack("MKDIR"); 598 } 599 600 removedir(name) 601 char *name; 602 { 603 604 if (rmdir(name) < 0) { 605 reply(550, "%s: %s.", name, sys_errlist[errno]); 606 return; 607 } 608 ack("RMDIR"); 609 } 610 611 pwd() 612 { 613 char path[MAXPATHLEN + 1]; 614 char *p; 615 616 if (getwd(path) == NULL) { 617 reply(451, "%s.", path); 618 return; 619 } 620 reply(251, "\"%s\" is current directory.", path); 621 } 622 623 char * 624 renamefrom(name) 625 char *name; 626 { 627 struct stat st; 628 629 if (stat(name, &st) < 0) { 630 reply(550, "%s: %s.", name, sys_errlist[errno]); 631 return ((char *)0); 632 } 633 reply(350, "File exists, ready for destination name"); 634 return (name); 635 } 636 637 renamecmd(from, to) 638 char *from, *to; 639 { 640 641 if (rename(from, to) < 0) { 642 reply(550, "rename: %s.", sys_errlist[errno]); 643 return; 644 } 645 ack("RNTO"); 646 } 647 648 int guest; 649 /* 650 * Test pathname for guest-user safety. 651 */ 652 inappropriate_request(name) 653 char *name; 654 { 655 int bogus = 0, depth = 0, length = strlen(name); 656 char *p, *s; 657 658 if (!guest) 659 return (0); 660 if (name[0] == '/' || name[0] == '|') 661 bogus = 1; 662 for (p = name; p < name+length;) { 663 s = p; /* start of token */ 664 while ( *p && *p!= '/') 665 p++; 666 *p = 0; 667 if (strcmp(s, "..") == 0) 668 depth -= 1; /* backing up */ 669 else if (strcmp(s, ".") == 0) 670 depth += 0; /* no change */ 671 else 672 depth += 1; /* descending */ 673 if (depth < 0) { 674 bogus = 1; 675 break; 676 } 677 } 678 if (bogus) 679 reply(553, "%s: pathname disallowed guest users", name); 680 return (bogus); 681 } 682 683 /* 684 * Convert network-format internet address 685 * to base 256 d.d.d.d representation. 686 */ 687 char * 688 ntoa(in) 689 struct in_addr in; 690 { 691 static char b[18]; 692 register char *p; 693 694 in.s_addr = ntohl(in.s_addr); 695 p = (char *)∈ 696 #define UC(b) (((int)b)&0xff) 697 sprintf(b, "%d.%d.%d.%d", UC(p[0]), UC(p[1]), UC(p[2]), UC(p[3])); 698 return (b); 699 } 700 701 dolog(sin) 702 struct sockaddr_in *sin; 703 { 704 struct hostent *hp = gethostbyaddr(&sin->sin_addr, 705 sizeof (struct in_addr), AF_INET); 706 char *remotehost; 707 time_t t; 708 709 if (hp) 710 remotehost = hp->h_name; 711 else 712 remotehost = "UNKNOWNHOST"; 713 t = time(0); 714 fprintf(stderr,"FTP: connection from %s at %s", remotehost, ctime(&t)); 715 fflush(stderr); 716 } 717