xref: /netbsd-src/libexec/ftpd/ftpd.c (revision ce63d6c20fc4ec8ddc95c84bb229e3c4ecf82b69)
1 /*
2  * Copyright (c) 1985, 1988, 1990 Regents of the University of California.
3  * 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 char copyright[] =
36 "@(#) Copyright (c) 1985, 1988, 1990 Regents of the University of California.\n\
37  All rights reserved.\n";
38 #endif /* not lint */
39 
40 #ifndef lint
41 static char sccsid[] = "@(#)ftpd.c	5.40 (Berkeley) 7/2/91";
42 #endif /* not lint */
43 
44 /*
45  * FTP server.
46  */
47 #include <sys/param.h>
48 #include <sys/stat.h>
49 #include <sys/ioctl.h>
50 #include <sys/socket.h>
51 #include <sys/wait.h>
52 
53 #include <netinet/in.h>
54 #include <netinet/in_systm.h>
55 #include <netinet/ip.h>
56 
57 #define	FTP_NAMES
58 #include <arpa/ftp.h>
59 #include <arpa/inet.h>
60 #include <arpa/telnet.h>
61 
62 #include <signal.h>
63 #include <dirent.h>
64 #include <fcntl.h>
65 #include <time.h>
66 #include <pwd.h>
67 #include <setjmp.h>
68 #include <netdb.h>
69 #include <errno.h>
70 #include <syslog.h>
71 #include <varargs.h>
72 #include <unistd.h>
73 #include <stdio.h>
74 #include <ctype.h>
75 #include <stdlib.h>
76 #include <string.h>
77 #include "pathnames.h"
78 
79 /*
80  * File containing login names
81  * NOT to be used on this machine.
82  * Commonly used to disallow uucp.
83  */
84 extern	int errno;
85 extern	char *crypt();
86 extern	char version[];
87 extern	char *home;		/* pointer to home directory for glob */
88 extern	FILE *ftpd_popen(), *fopen(), *freopen();
89 extern	int  ftpd_pclose(), fclose();
90 extern	char *getline();
91 extern	char cbuf[];
92 extern	off_t restart_point;
93 
94 struct	sockaddr_in ctrl_addr;
95 struct	sockaddr_in data_source;
96 struct	sockaddr_in data_dest;
97 struct	sockaddr_in his_addr;
98 struct	sockaddr_in pasv_addr;
99 
100 int	data;
101 jmp_buf	errcatch, urgcatch;
102 int	logged_in;
103 struct	passwd *pw;
104 int	debug;
105 int	timeout = 900;    /* timeout after 15 minutes of inactivity */
106 int	maxtimeout = 7200;/* don't allow idle time to be set beyond 2 hours */
107 int	logging;
108 int	guest;
109 int	type;
110 int	form;
111 int	stru;			/* avoid C keyword */
112 int	mode;
113 int	usedefault = 1;		/* for data transfers */
114 int	pdata = -1;		/* for passive mode */
115 int	transflag;
116 off_t	file_size;
117 off_t	byte_count;
118 #if !defined(CMASK) || CMASK == 0
119 #undef CMASK
120 #define CMASK 027
121 #endif
122 int	defumask = CMASK;		/* default umask value */
123 char	tmpline[7];
124 char	hostname[MAXHOSTNAMELEN];
125 char	remotehost[MAXHOSTNAMELEN];
126 
127 /*
128  * Timeout intervals for retrying connections
129  * to hosts that don't accept PORT cmds.  This
130  * is a kludge, but given the problems with TCP...
131  */
132 #define	SWAITMAX	90	/* wait at most 90 seconds */
133 #define	SWAITINT	5	/* interval between retries */
134 
135 int	swaitmax = SWAITMAX;
136 int	swaitint = SWAITINT;
137 
138 void	lostconn(), myoob();
139 FILE	*getdatasock(), *dataconn();
140 
141 #ifdef SETPROCTITLE
142 char	**Argv = NULL;		/* pointer to argument vector */
143 char	*LastArgv = NULL;	/* end of argv */
144 char	proctitle[BUFSIZ];	/* initial part of title */
145 #endif /* SETPROCTITLE */
146 
147 main(argc, argv, envp)
148 	int argc;
149 	char *argv[];
150 	char **envp;
151 {
152 	int addrlen, on = 1, tos;
153 	char *cp;
154 
155 	/*
156 	 * LOG_NDELAY sets up the logging connection immediately,
157 	 * necessary for anonymous ftp's that chroot and can't do it later.
158 	 */
159 	openlog("ftpd", LOG_PID | LOG_NDELAY, LOG_DAEMON);
160 	addrlen = sizeof (his_addr);
161 	if (getpeername(0, (struct sockaddr *)&his_addr, &addrlen) < 0) {
162 		syslog(LOG_ERR, "getpeername (%s): %m",argv[0]);
163 		exit(1);
164 	}
165 	addrlen = sizeof (ctrl_addr);
166 	if (getsockname(0, (struct sockaddr *)&ctrl_addr, &addrlen) < 0) {
167 		syslog(LOG_ERR, "getsockname (%s): %m",argv[0]);
168 		exit(1);
169 	}
170 #ifdef IP_TOS
171 	tos = IPTOS_LOWDELAY;
172 	if (setsockopt(0, IPPROTO_IP, IP_TOS, (char *)&tos, sizeof(int)) < 0)
173 		syslog(LOG_WARNING, "setsockopt (IP_TOS): %m");
174 #endif
175 	data_source.sin_port = htons(ntohs(ctrl_addr.sin_port) - 1);
176 	debug = 0;
177 #ifdef SETPROCTITLE
178 	/*
179 	 *  Save start and extent of argv for setproctitle.
180 	 */
181 	Argv = argv;
182 	while (*envp)
183 		envp++;
184 	LastArgv = envp[-1] + strlen(envp[-1]);
185 #endif /* SETPROCTITLE */
186 
187 	argc--, argv++;
188 	while (argc > 0 && *argv[0] == '-') {
189 		for (cp = &argv[0][1]; *cp; cp++) switch (*cp) {
190 
191 		case 'v':
192 			debug = 1;
193 			break;
194 
195 		case 'd':
196 			debug = 1;
197 			break;
198 
199 		case 'l':
200 			logging = 1;
201 			break;
202 
203 		case 't':
204 			timeout = atoi(++cp);
205 			if (maxtimeout < timeout)
206 				maxtimeout = timeout;
207 			goto nextopt;
208 
209 		case 'T':
210 			maxtimeout = atoi(++cp);
211 			if (timeout > maxtimeout)
212 				timeout = maxtimeout;
213 			goto nextopt;
214 
215 		case 'u':
216 		    {
217 			int val = 0;
218 
219 			while (*++cp && *cp >= '0' && *cp <= '9')
220 				val = val*8 + *cp - '0';
221 			if (*cp)
222 				fprintf(stderr, "ftpd: Bad value for -u\n");
223 			else
224 				defumask = val;
225 			goto nextopt;
226 		    }
227 
228 		default:
229 			fprintf(stderr, "ftpd: Unknown flag -%c ignored.\n",
230 			     *cp);
231 			break;
232 		}
233 nextopt:
234 		argc--, argv++;
235 	}
236 	(void) freopen(_PATH_DEVNULL, "w", stderr);
237 	(void) signal(SIGPIPE, lostconn);
238 	(void) signal(SIGCHLD, SIG_IGN);
239 	if ((int)signal(SIGURG, myoob) < 0)
240 		syslog(LOG_ERR, "signal: %m");
241 
242 	/* Try to handle urgent data inline */
243 #ifdef SO_OOBINLINE
244 	if (setsockopt(0, SOL_SOCKET, SO_OOBINLINE, (char *)&on, sizeof(on)) < 0)
245 		syslog(LOG_ERR, "setsockopt: %m");
246 #endif
247 
248 #ifdef	F_SETOWN
249 	if (fcntl(fileno(stdin), F_SETOWN, getpid()) == -1)
250 		syslog(LOG_ERR, "fcntl F_SETOWN: %m");
251 #endif
252 	dolog(&his_addr);
253 	/*
254 	 * Set up default state
255 	 */
256 	data = -1;
257 	type = TYPE_A;
258 	form = FORM_N;
259 	stru = STRU_F;
260 	mode = MODE_S;
261 	tmpline[0] = '\0';
262 	(void) gethostname(hostname, sizeof (hostname));
263 	reply(220, "%s FTP server (%s) ready.", hostname, version);
264 	(void) setjmp(errcatch);
265 	for (;;)
266 		(void) yyparse();
267 	/* NOTREACHED */
268 }
269 
270 void
271 lostconn()
272 {
273 	if (debug)
274 		syslog(LOG_DEBUG, "lost connection");
275 	dologout(-1);
276 }
277 
278 static char ttyline[20];
279 
280 /*
281  * Helper function for sgetpwnam().
282  */
283 char *
284 sgetsave(s)
285 	char *s;
286 {
287 	char *new = malloc((unsigned) strlen(s) + 1);
288 
289 	if (new == NULL) {
290 		perror_reply(421, "Local resource failure: malloc");
291 		dologout(1);
292 		/* NOTREACHED */
293 	}
294 	(void) strcpy(new, s);
295 	return (new);
296 }
297 
298 /*
299  * Save the result of a getpwnam.  Used for USER command, since
300  * the data returned must not be clobbered by any other command
301  * (e.g., globbing).
302  */
303 struct passwd *
304 sgetpwnam(name)
305 	char *name;
306 {
307 	static struct passwd save;
308 	register struct passwd *p;
309 	char *sgetsave();
310 
311 	if ((p = getpwnam(name)) == NULL)
312 		return (p);
313 	if (save.pw_name) {
314 		free(save.pw_name);
315 		free(save.pw_passwd);
316 		free(save.pw_gecos);
317 		free(save.pw_dir);
318 		free(save.pw_shell);
319 	}
320 	save = *p;
321 	save.pw_name = sgetsave(p->pw_name);
322 	save.pw_passwd = sgetsave(p->pw_passwd);
323 	save.pw_gecos = sgetsave(p->pw_gecos);
324 	save.pw_dir = sgetsave(p->pw_dir);
325 	save.pw_shell = sgetsave(p->pw_shell);
326 	return (&save);
327 }
328 
329 int login_attempts;		/* number of failed login attempts */
330 int askpasswd;			/* had user command, ask for passwd */
331 
332 /*
333  * USER command.
334  * Sets global passwd pointer pw if named account exists and is acceptable;
335  * sets askpasswd if a PASS command is expected.  If logged in previously,
336  * need to reset state.  If name is "ftp" or "anonymous", the name is not in
337  * _PATH_FTPUSERS, and ftp account exists, set guest and pw, then just return.
338  * If account doesn't exist, ask for passwd anyway.  Otherwise, check user
339  * requesting login privileges.  Disallow anyone who does not have a standard
340  * shell as returned by getusershell().  Disallow anyone mentioned in the file
341  * _PATH_FTPUSERS to allow people such as root and uucp to be avoided.
342  */
343 user(name)
344 	char *name;
345 {
346 	register char *cp;
347 	char *shell;
348 	char *getusershell();
349 
350 	if (logged_in) {
351 		if (guest) {
352 			reply(530, "Can't change user from guest login.");
353 			return;
354 		}
355 		end_login();
356 	}
357 
358 	guest = 0;
359 	if (strcmp(name, "ftp") == 0 || strcmp(name, "anonymous") == 0) {
360 		if (checkuser("ftp") || checkuser("anonymous"))
361 			reply(530, "User %s access denied.", name);
362 		else if ((pw = sgetpwnam("ftp")) != NULL) {
363 			guest = 1;
364 			askpasswd = 1;
365 			reply(331, "Guest login ok, send ident as password.");
366 		} else
367 			reply(530, "User %s unknown.", name);
368 		return;
369 	}
370 	if (pw = sgetpwnam(name)) {
371 		if ((shell = pw->pw_shell) == NULL || *shell == 0)
372 			shell = _PATH_BSHELL;
373 		while ((cp = getusershell()) != NULL)
374 			if (strcmp(cp, shell) == 0)
375 				break;
376 		endusershell();
377 		if (cp == NULL || checkuser(name)) {
378 			reply(530, "User %s access denied.", name);
379 			if (logging)
380 				syslog(LOG_NOTICE,
381 				    "FTP LOGIN REFUSED FROM %s, %s",
382 				    remotehost, name);
383 			pw = (struct passwd *) NULL;
384 			return;
385 		}
386 	}
387 	reply(331, "Password required for %s.", name);
388 	askpasswd = 1;
389 	/*
390 	 * Delay before reading passwd after first failed
391 	 * attempt to slow down passwd-guessing programs.
392 	 */
393 	if (login_attempts)
394 		sleep((unsigned) login_attempts);
395 }
396 
397 /*
398  * Check if a user is in the file _PATH_FTPUSERS
399  */
400 checkuser(name)
401 	char *name;
402 {
403 	register FILE *fd;
404 	register char *p;
405 	char line[BUFSIZ];
406 
407 	if ((fd = fopen(_PATH_FTPUSERS, "r")) != NULL) {
408 		while (fgets(line, sizeof(line), fd) != NULL)
409 			if ((p = index(line, '\n')) != NULL) {
410 				*p = '\0';
411 				if (line[0] == '#')
412 					continue;
413 				if (strcmp(line, name) == 0)
414 					return (1);
415 			}
416 		(void) fclose(fd);
417 	}
418 	return (0);
419 }
420 
421 /*
422  * Terminate login as previous user, if any, resetting state;
423  * used when USER command is given or login fails.
424  */
425 end_login()
426 {
427 
428 	(void) seteuid((uid_t)0);
429 	if (logged_in)
430 		logwtmp(ttyline, "", "");
431 	pw = NULL;
432 	logged_in = 0;
433 	guest = 0;
434 }
435 
436 pass(passwd)
437 	char *passwd;
438 {
439 	char *xpasswd, *salt;
440 
441 	if (logged_in || askpasswd == 0) {
442 		reply(503, "Login with USER first.");
443 		return;
444 	}
445 	askpasswd = 0;
446 	if (!guest) {		/* "ftp" is only account allowed no password */
447 		if (pw == NULL)
448 			salt = "xx";
449 		else
450 			salt = pw->pw_passwd;
451 		xpasswd = crypt(passwd, salt);
452 		/* The strcmp does not catch null passwords! */
453 		if (pw == NULL || *pw->pw_passwd == '\0' ||
454 		    strcmp(xpasswd, pw->pw_passwd)) {
455 			reply(530, "Login incorrect.");
456 			pw = NULL;
457 			if (login_attempts++ >= 5) {
458 				syslog(LOG_NOTICE,
459 				    "repeated login failures from %s",
460 				    remotehost);
461 				exit(0);
462 			}
463 			return;
464 		}
465 	}
466 	login_attempts = 0;		/* this time successful */
467 	(void) setegid((gid_t)pw->pw_gid);
468 	(void) initgroups(pw->pw_name, pw->pw_gid);
469 
470 	/* open wtmp before chroot */
471 	(void)sprintf(ttyline, "ftp%d", getpid());
472 	logwtmp(ttyline, pw->pw_name, remotehost);
473 	logged_in = 1;
474 
475 	if (guest) {
476 		/*
477 		 * We MUST do a chdir() after the chroot. Otherwise
478 		 * the old current directory will be accessible as "."
479 		 * outside the new root!
480 		 */
481 		if (chroot(pw->pw_dir) < 0 || chdir("/") < 0) {
482 			reply(550, "Can't set guest privileges.");
483 			goto bad;
484 		}
485 	} else if (chdir(pw->pw_dir) < 0) {
486 		if (chdir("/") < 0) {
487 			reply(530, "User %s: can't change directory to %s.",
488 			    pw->pw_name, pw->pw_dir);
489 			goto bad;
490 		} else
491 			lreply(230, "No directory! Logging in with home=/");
492 	}
493 	if (seteuid((uid_t)pw->pw_uid) < 0) {
494 		reply(550, "Can't set uid.");
495 		goto bad;
496 	}
497 	if (guest) {
498 		reply(230, "Guest login ok, access restrictions apply.");
499 #ifdef SETPROCTITLE
500 		sprintf(proctitle, "%s: anonymous/%.*s", remotehost,
501 		    sizeof(proctitle) - sizeof(remotehost) -
502 		    sizeof(": anonymous/"), passwd);
503 		setproctitle(proctitle);
504 #endif /* SETPROCTITLE */
505 		if (logging)
506 			syslog(LOG_INFO, "ANONYMOUS FTP LOGIN FROM %s, %s",
507 			    remotehost, passwd);
508 	} else {
509 		reply(230, "User %s logged in.", pw->pw_name);
510 #ifdef SETPROCTITLE
511 		sprintf(proctitle, "%s: %s", remotehost, pw->pw_name);
512 		setproctitle(proctitle);
513 #endif /* SETPROCTITLE */
514 		if (logging)
515 			syslog(LOG_INFO, "FTP LOGIN FROM %s, %s",
516 			    remotehost, pw->pw_name);
517 	}
518 	home = pw->pw_dir;		/* home dir for globbing */
519 	(void) umask(defumask);
520 	return;
521 bad:
522 	/* Forget all about it... */
523 	end_login();
524 }
525 
526 retrieve(cmd, name)
527 	char *cmd, *name;
528 {
529 	FILE *fin, *dout;
530 	struct stat st;
531 	int (*closefunc)();
532 
533 	if (cmd == 0) {
534 		fin = fopen(name, "r"), closefunc = fclose;
535 		st.st_size = 0;
536 	} else {
537 		char line[BUFSIZ];
538 
539 		(void) sprintf(line, cmd, name), name = line;
540 		fin = ftpd_popen(line, "r"), closefunc = ftpd_pclose;
541 		st.st_size = -1;
542 		st.st_blksize = BUFSIZ;
543 	}
544 	if (fin == NULL) {
545 		if (errno != 0)
546 			perror_reply(550, name);
547 		return;
548 	}
549 	if (cmd == 0 &&
550 	    (fstat(fileno(fin), &st) < 0 || (st.st_mode&S_IFMT) != S_IFREG)) {
551 		reply(550, "%s: not a plain file.", name);
552 		goto done;
553 	}
554 	if (restart_point) {
555 		if (type == TYPE_A) {
556 			register int i, n, c;
557 
558 			n = restart_point;
559 			i = 0;
560 			while (i++ < n) {
561 				if ((c=getc(fin)) == EOF) {
562 					perror_reply(550, name);
563 					goto done;
564 				}
565 				if (c == '\n')
566 					i++;
567 			}
568 		} else if (lseek(fileno(fin), restart_point, L_SET) < 0) {
569 			perror_reply(550, name);
570 			goto done;
571 		}
572 	}
573 	dout = dataconn(name, st.st_size, "w");
574 	if (dout == NULL)
575 		goto done;
576 	send_data(fin, dout, st.st_blksize);
577 	(void) fclose(dout);
578 	data = -1;
579 	pdata = -1;
580 done:
581 	(*closefunc)(fin);
582 }
583 
584 store(name, mode, unique)
585 	char *name, *mode;
586 	int unique;
587 {
588 	FILE *fout, *din;
589 	struct stat st;
590 	int (*closefunc)();
591 	char *gunique();
592 
593 	if (unique && stat(name, &st) == 0 &&
594 	    (name = gunique(name)) == NULL)
595 		return;
596 
597 	if (restart_point)
598 		mode = "r+w";
599 	fout = fopen(name, mode);
600 	closefunc = fclose;
601 	if (fout == NULL) {
602 		perror_reply(553, name);
603 		return;
604 	}
605 	if (restart_point) {
606 		if (type == TYPE_A) {
607 			register int i, n, c;
608 
609 			n = restart_point;
610 			i = 0;
611 			while (i++ < n) {
612 				if ((c=getc(fout)) == EOF) {
613 					perror_reply(550, name);
614 					goto done;
615 				}
616 				if (c == '\n')
617 					i++;
618 			}
619 			/*
620 			 * We must do this seek to "current" position
621 			 * because we are changing from reading to
622 			 * writing.
623 			 */
624 			if (fseek(fout, 0L, L_INCR) < 0) {
625 				perror_reply(550, name);
626 				goto done;
627 			}
628 		} else if (lseek(fileno(fout), restart_point, L_SET) < 0) {
629 			perror_reply(550, name);
630 			goto done;
631 		}
632 	}
633 	din = dataconn(name, (off_t)-1, "r");
634 	if (din == NULL)
635 		goto done;
636 	if (receive_data(din, fout) == 0) {
637 		if (unique)
638 			reply(226, "Transfer complete (unique file name:%s).",
639 			    name);
640 		else
641 			reply(226, "Transfer complete.");
642 	}
643 	(void) fclose(din);
644 	data = -1;
645 	pdata = -1;
646 done:
647 	(*closefunc)(fout);
648 }
649 
650 FILE *
651 getdatasock(mode)
652 	char *mode;
653 {
654 	int s, on = 1, tries;
655 
656 	if (data >= 0)
657 		return (fdopen(data, mode));
658 	(void) seteuid((uid_t)0);
659 	s = socket(AF_INET, SOCK_STREAM, 0);
660 	if (s < 0)
661 		goto bad;
662 	if (setsockopt(s, SOL_SOCKET, SO_REUSEADDR,
663 	    (char *) &on, sizeof (on)) < 0)
664 		goto bad;
665 	/* anchor socket to avoid multi-homing problems */
666 	data_source.sin_family = AF_INET;
667 	data_source.sin_addr = ctrl_addr.sin_addr;
668 	for (tries = 1; ; tries++) {
669 		if (bind(s, (struct sockaddr *)&data_source,
670 		    sizeof (data_source)) >= 0)
671 			break;
672 		if (errno != EADDRINUSE || tries > 10)
673 			goto bad;
674 		sleep(tries);
675 	}
676 	(void) seteuid((uid_t)pw->pw_uid);
677 #ifdef IP_TOS
678 	on = IPTOS_THROUGHPUT;
679 	if (setsockopt(s, IPPROTO_IP, IP_TOS, (char *)&on, sizeof(int)) < 0)
680 		syslog(LOG_WARNING, "setsockopt (IP_TOS): %m");
681 #endif
682 	return (fdopen(s, mode));
683 bad:
684 	(void) seteuid((uid_t)pw->pw_uid);
685 	(void) close(s);
686 	return (NULL);
687 }
688 
689 FILE *
690 dataconn(name, size, mode)
691 	char *name;
692 	off_t size;
693 	char *mode;
694 {
695 	char sizebuf[32];
696 	FILE *file;
697 	int retry = 0, tos;
698 
699 	file_size = size;
700 	byte_count = 0;
701 	if (size != (off_t) -1)
702 		(void) sprintf (sizebuf, " (%ld bytes)", size);
703 	else
704 		(void) strcpy(sizebuf, "");
705 	if (pdata >= 0) {
706 		struct sockaddr_in from;
707 		int s, fromlen = sizeof(from);
708 
709 		s = accept(pdata, (struct sockaddr *)&from, &fromlen);
710 		if (s < 0) {
711 			reply(425, "Can't open data connection.");
712 			(void) close(pdata);
713 			pdata = -1;
714 			return(NULL);
715 		}
716 		(void) close(pdata);
717 		pdata = s;
718 #ifdef IP_TOS
719 		tos = IPTOS_LOWDELAY;
720 		(void) setsockopt(s, IPPROTO_IP, IP_TOS, (char *)&tos,
721 		    sizeof(int));
722 #endif
723 		reply(150, "Opening %s mode data connection for %s%s.",
724 		     type == TYPE_A ? "ASCII" : "BINARY", name, sizebuf);
725 		return(fdopen(pdata, mode));
726 	}
727 	if (data >= 0) {
728 		reply(125, "Using existing data connection for %s%s.",
729 		    name, sizebuf);
730 		usedefault = 1;
731 		return (fdopen(data, mode));
732 	}
733 	if (usedefault)
734 		data_dest = his_addr;
735 	usedefault = 1;
736 	file = getdatasock(mode);
737 	if (file == NULL) {
738 		reply(425, "Can't create data socket (%s,%d): %s.",
739 		    inet_ntoa(data_source.sin_addr),
740 		    ntohs(data_source.sin_port), strerror(errno));
741 		return (NULL);
742 	}
743 	data = fileno(file);
744 	while (connect(data, (struct sockaddr *)&data_dest,
745 	    sizeof (data_dest)) < 0) {
746 		if (errno == EADDRINUSE && retry < swaitmax) {
747 			sleep((unsigned) swaitint);
748 			retry += swaitint;
749 			continue;
750 		}
751 		perror_reply(425, "Can't build data connection");
752 		(void) fclose(file);
753 		data = -1;
754 		return (NULL);
755 	}
756 	reply(150, "Opening %s mode data connection for %s%s.",
757 	     type == TYPE_A ? "ASCII" : "BINARY", name, sizebuf);
758 	return (file);
759 }
760 
761 /*
762  * Tranfer the contents of "instr" to
763  * "outstr" peer using the appropriate
764  * encapsulation of the data subject
765  * to Mode, Structure, and Type.
766  *
767  * NB: Form isn't handled.
768  */
769 send_data(instr, outstr, blksize)
770 	FILE *instr, *outstr;
771 	off_t blksize;
772 {
773 	register int c, cnt;
774 	register char *buf;
775 	int netfd, filefd;
776 
777 	transflag++;
778 	if (setjmp(urgcatch)) {
779 		transflag = 0;
780 		return;
781 	}
782 	switch (type) {
783 
784 	case TYPE_A:
785 		while ((c = getc(instr)) != EOF) {
786 			byte_count++;
787 			if (c == '\n') {
788 				if (ferror(outstr))
789 					goto data_err;
790 				(void) putc('\r', outstr);
791 			}
792 			(void) putc(c, outstr);
793 		}
794 		fflush(outstr);
795 		transflag = 0;
796 		if (ferror(instr))
797 			goto file_err;
798 		if (ferror(outstr))
799 			goto data_err;
800 		reply(226, "Transfer complete.");
801 		return;
802 
803 	case TYPE_I:
804 	case TYPE_L:
805 		if ((buf = malloc((u_int)blksize)) == NULL) {
806 			transflag = 0;
807 			perror_reply(451, "Local resource failure: malloc");
808 			return;
809 		}
810 		netfd = fileno(outstr);
811 		filefd = fileno(instr);
812 		while ((cnt = read(filefd, buf, (u_int)blksize)) > 0 &&
813 		    write(netfd, buf, cnt) == cnt)
814 			byte_count += cnt;
815 		transflag = 0;
816 		(void)free(buf);
817 		if (cnt != 0) {
818 			if (cnt < 0)
819 				goto file_err;
820 			goto data_err;
821 		}
822 		reply(226, "Transfer complete.");
823 		return;
824 	default:
825 		transflag = 0;
826 		reply(550, "Unimplemented TYPE %d in send_data", type);
827 		return;
828 	}
829 
830 data_err:
831 	transflag = 0;
832 	perror_reply(426, "Data connection");
833 	return;
834 
835 file_err:
836 	transflag = 0;
837 	perror_reply(551, "Error on input file");
838 }
839 
840 /*
841  * Transfer data from peer to
842  * "outstr" using the appropriate
843  * encapulation of the data subject
844  * to Mode, Structure, and Type.
845  *
846  * N.B.: Form isn't handled.
847  */
848 receive_data(instr, outstr)
849 	FILE *instr, *outstr;
850 {
851 	register int c;
852 	int cnt, bare_lfs = 0;
853 	char buf[BUFSIZ];
854 
855 	transflag++;
856 	if (setjmp(urgcatch)) {
857 		transflag = 0;
858 		return (-1);
859 	}
860 	switch (type) {
861 
862 	case TYPE_I:
863 	case TYPE_L:
864 		while ((cnt = read(fileno(instr), buf, sizeof buf)) > 0) {
865 			if (write(fileno(outstr), buf, cnt) != cnt)
866 				goto file_err;
867 			byte_count += cnt;
868 		}
869 		if (cnt < 0)
870 			goto data_err;
871 		transflag = 0;
872 		return (0);
873 
874 	case TYPE_E:
875 		reply(553, "TYPE E not implemented.");
876 		transflag = 0;
877 		return (-1);
878 
879 	case TYPE_A:
880 		while ((c = getc(instr)) != EOF) {
881 			byte_count++;
882 			if (c == '\n')
883 				bare_lfs++;
884 			while (c == '\r') {
885 				if (ferror(outstr))
886 					goto data_err;
887 				if ((c = getc(instr)) != '\n') {
888 					(void) putc ('\r', outstr);
889 					if (c == '\0' || c == EOF)
890 						goto contin2;
891 				}
892 			}
893 			(void) putc(c, outstr);
894 	contin2:	;
895 		}
896 		fflush(outstr);
897 		if (ferror(instr))
898 			goto data_err;
899 		if (ferror(outstr))
900 			goto file_err;
901 		transflag = 0;
902 		if (bare_lfs) {
903 			lreply(230, "WARNING! %d bare linefeeds received in ASCII mode", bare_lfs);
904 			printf("   File may not have transferred correctly.\r\n");
905 		}
906 		return (0);
907 	default:
908 		reply(550, "Unimplemented TYPE %d in receive_data", type);
909 		transflag = 0;
910 		return (-1);
911 	}
912 
913 data_err:
914 	transflag = 0;
915 	perror_reply(426, "Data Connection");
916 	return (-1);
917 
918 file_err:
919 	transflag = 0;
920 	perror_reply(452, "Error writing file");
921 	return (-1);
922 }
923 
924 statfilecmd(filename)
925 	char *filename;
926 {
927 	char line[BUFSIZ];
928 	FILE *fin;
929 	int c;
930 
931 	(void) sprintf(line, "/bin/ls -lgA %s", filename);
932 	fin = ftpd_popen(line, "r");
933 	lreply(211, "status of %s:", filename);
934 	while ((c = getc(fin)) != EOF) {
935 		if (c == '\n') {
936 			if (ferror(stdout)){
937 				perror_reply(421, "control connection");
938 				(void) ftpd_pclose(fin);
939 				dologout(1);
940 				/* NOTREACHED */
941 			}
942 			if (ferror(fin)) {
943 				perror_reply(551, filename);
944 				(void) ftpd_pclose(fin);
945 				return;
946 			}
947 			(void) putc('\r', stdout);
948 		}
949 		(void) putc(c, stdout);
950 	}
951 	(void) ftpd_pclose(fin);
952 	reply(211, "End of Status");
953 }
954 
955 statcmd()
956 {
957 	struct sockaddr_in *sin;
958 	u_char *a, *p;
959 
960 	lreply(211, "%s FTP server status:", hostname, version);
961 	printf("     %s\r\n", version);
962 	printf("     Connected to %s", remotehost);
963 	if (!isdigit(remotehost[0]))
964 		printf(" (%s)", inet_ntoa(his_addr.sin_addr));
965 	printf("\r\n");
966 	if (logged_in) {
967 		if (guest)
968 			printf("     Logged in anonymously\r\n");
969 		else
970 			printf("     Logged in as %s\r\n", pw->pw_name);
971 	} else if (askpasswd)
972 		printf("     Waiting for password\r\n");
973 	else
974 		printf("     Waiting for user name\r\n");
975 	printf("     TYPE: %s", typenames[type]);
976 	if (type == TYPE_A || type == TYPE_E)
977 		printf(", FORM: %s", formnames[form]);
978 	if (type == TYPE_L)
979 #if NBBY == 8
980 		printf(" %d", NBBY);
981 #else
982 		printf(" %d", bytesize);	/* need definition! */
983 #endif
984 	printf("; STRUcture: %s; transfer MODE: %s\r\n",
985 	    strunames[stru], modenames[mode]);
986 	if (data != -1)
987 		printf("     Data connection open\r\n");
988 	else if (pdata != -1) {
989 		printf("     in Passive mode");
990 		sin = &pasv_addr;
991 		goto printaddr;
992 	} else if (usedefault == 0) {
993 		printf("     PORT");
994 		sin = &data_dest;
995 printaddr:
996 		a = (u_char *) &sin->sin_addr;
997 		p = (u_char *) &sin->sin_port;
998 #define UC(b) (((int) b) & 0xff)
999 		printf(" (%d,%d,%d,%d,%d,%d)\r\n", UC(a[0]),
1000 			UC(a[1]), UC(a[2]), UC(a[3]), UC(p[0]), UC(p[1]));
1001 #undef UC
1002 	} else
1003 		printf("     No data connection\r\n");
1004 	reply(211, "End of status");
1005 }
1006 
1007 fatal(s)
1008 	char *s;
1009 {
1010 	reply(451, "Error in server: %s\n", s);
1011 	reply(221, "Closing connection due to server error.");
1012 	dologout(0);
1013 	/* NOTREACHED */
1014 }
1015 
1016 /* VARARGS2 */
1017 reply(n, fmt, p0, p1, p2, p3, p4, p5)
1018 	int n;
1019 	char *fmt;
1020 {
1021 	printf("%d ", n);
1022 	printf(fmt, p0, p1, p2, p3, p4, p5);
1023 	printf("\r\n");
1024 	(void)fflush(stdout);
1025 	if (debug) {
1026 		syslog(LOG_DEBUG, "<--- %d ", n);
1027 		syslog(LOG_DEBUG, fmt, p0, p1, p2, p3, p4, p5);
1028 }
1029 }
1030 
1031 /* VARARGS2 */
1032 lreply(n, fmt, p0, p1, p2, p3, p4, p5)
1033 	int n;
1034 	char *fmt;
1035 {
1036 	printf("%d- ", n);
1037 	printf(fmt, p0, p1, p2, p3, p4, p5);
1038 	printf("\r\n");
1039 	(void)fflush(stdout);
1040 	if (debug) {
1041 		syslog(LOG_DEBUG, "<--- %d- ", n);
1042 		syslog(LOG_DEBUG, fmt, p0, p1, p2, p3, p4, p5);
1043 	}
1044 }
1045 
1046 ack(s)
1047 	char *s;
1048 {
1049 	reply(250, "%s command successful.", s);
1050 }
1051 
1052 nack(s)
1053 	char *s;
1054 {
1055 	reply(502, "%s command not implemented.", s);
1056 }
1057 
1058 /* ARGSUSED */
1059 yyerror(s)
1060 	char *s;
1061 {
1062 	char *cp;
1063 
1064 	if (cp = index(cbuf,'\n'))
1065 		*cp = '\0';
1066 	reply(500, "'%s': command not understood.", cbuf);
1067 }
1068 
1069 delete(name)
1070 	char *name;
1071 {
1072 	struct stat st;
1073 
1074 	if (stat(name, &st) < 0) {
1075 		perror_reply(550, name);
1076 		return;
1077 	}
1078 	if ((st.st_mode&S_IFMT) == S_IFDIR) {
1079 		if (rmdir(name) < 0) {
1080 			perror_reply(550, name);
1081 			return;
1082 		}
1083 		goto done;
1084 	}
1085 	if (unlink(name) < 0) {
1086 		perror_reply(550, name);
1087 		return;
1088 	}
1089 done:
1090 	ack("DELE");
1091 }
1092 
1093 cwd(path)
1094 	char *path;
1095 {
1096 	if (chdir(path) < 0)
1097 		perror_reply(550, path);
1098 	else
1099 		ack("CWD");
1100 }
1101 
1102 makedir(name)
1103 	char *name;
1104 {
1105 	if (mkdir(name, 0777) < 0)
1106 		perror_reply(550, name);
1107 	else
1108 		reply(257, "MKD command successful.");
1109 }
1110 
1111 removedir(name)
1112 	char *name;
1113 {
1114 	if (rmdir(name) < 0)
1115 		perror_reply(550, name);
1116 	else
1117 		ack("RMD");
1118 }
1119 
1120 pwd()
1121 {
1122 	char path[MAXPATHLEN + 1];
1123 	extern char *getwd();
1124 
1125 	if (getwd(path) == (char *)NULL)
1126 		reply(550, "%s.", path);
1127 	else
1128 		reply(257, "\"%s\" is current directory.", path);
1129 }
1130 
1131 char *
1132 renamefrom(name)
1133 	char *name;
1134 {
1135 	struct stat st;
1136 
1137 	if (stat(name, &st) < 0) {
1138 		perror_reply(550, name);
1139 		return ((char *)0);
1140 	}
1141 	reply(350, "File exists, ready for destination name");
1142 	return (name);
1143 }
1144 
1145 renamecmd(from, to)
1146 	char *from, *to;
1147 {
1148 	if (rename(from, to) < 0)
1149 		perror_reply(550, "rename");
1150 	else
1151 		ack("RNTO");
1152 }
1153 
1154 dolog(sin)
1155 	struct sockaddr_in *sin;
1156 {
1157 	struct hostent *hp = gethostbyaddr((char *)&sin->sin_addr,
1158 		sizeof (struct in_addr), AF_INET);
1159 	time_t t, time();
1160 	extern char *ctime();
1161 
1162 	if (hp)
1163 		(void) strncpy(remotehost, hp->h_name, sizeof (remotehost));
1164 	else
1165 		(void) strncpy(remotehost, inet_ntoa(sin->sin_addr),
1166 		    sizeof (remotehost));
1167 #ifdef SETPROCTITLE
1168 	sprintf(proctitle, "%s: connected", remotehost);
1169 	setproctitle(proctitle);
1170 #endif /* SETPROCTITLE */
1171 
1172 	if (logging) {
1173 		t = time((time_t *) 0);
1174 		syslog(LOG_INFO, "connection from %s at %s",
1175 		    remotehost, ctime(&t));
1176 	}
1177 }
1178 
1179 /*
1180  * Record logout in wtmp file
1181  * and exit with supplied status.
1182  */
1183 dologout(status)
1184 	int status;
1185 {
1186 	if (logged_in) {
1187 		(void) seteuid((uid_t)0);
1188 		logwtmp(ttyline, "", "");
1189 	}
1190 	/* beware of flushing buffers after a SIGPIPE */
1191 	_exit(status);
1192 }
1193 
1194 void
1195 myoob()
1196 {
1197 	char *cp;
1198 
1199 	/* only process if transfer occurring */
1200 	if (!transflag)
1201 		return;
1202 	cp = tmpline;
1203 	if (getline(cp, 7, stdin) == NULL) {
1204 		reply(221, "You could at least say goodbye.");
1205 		dologout(0);
1206 	}
1207 	upper(cp);
1208 	if (strcmp(cp, "ABOR\r\n") == 0) {
1209 		tmpline[0] = '\0';
1210 		reply(426, "Transfer aborted. Data connection closed.");
1211 		reply(226, "Abort successful");
1212 		longjmp(urgcatch, 1);
1213 	}
1214 	if (strcmp(cp, "STAT\r\n") == 0) {
1215 		if (file_size != (off_t) -1)
1216 			reply(213, "Status: %lu of %lu bytes transferred",
1217 			    byte_count, file_size);
1218 		else
1219 			reply(213, "Status: %lu bytes transferred", byte_count);
1220 	}
1221 }
1222 
1223 /*
1224  * Note: a response of 425 is not mentioned as a possible response to
1225  * 	the PASV command in RFC959. However, it has been blessed as
1226  * 	a legitimate response by Jon Postel in a telephone conversation
1227  *	with Rick Adams on 25 Jan 89.
1228  */
1229 passive()
1230 {
1231 	int len;
1232 	register char *p, *a;
1233 
1234 	pdata = socket(AF_INET, SOCK_STREAM, 0);
1235 	if (pdata < 0) {
1236 		perror_reply(425, "Can't open passive connection");
1237 		return;
1238 	}
1239 	pasv_addr = ctrl_addr;
1240 	pasv_addr.sin_port = 0;
1241 	(void) seteuid((uid_t)0);
1242 	if (bind(pdata, (struct sockaddr *)&pasv_addr, sizeof(pasv_addr)) < 0) {
1243 		(void) seteuid((uid_t)pw->pw_uid);
1244 		goto pasv_error;
1245 	}
1246 	(void) seteuid((uid_t)pw->pw_uid);
1247 	len = sizeof(pasv_addr);
1248 	if (getsockname(pdata, (struct sockaddr *) &pasv_addr, &len) < 0)
1249 		goto pasv_error;
1250 	if (listen(pdata, 1) < 0)
1251 		goto pasv_error;
1252 	a = (char *) &pasv_addr.sin_addr;
1253 	p = (char *) &pasv_addr.sin_port;
1254 
1255 #define UC(b) (((int) b) & 0xff)
1256 
1257 	reply(227, "Entering Passive Mode (%d,%d,%d,%d,%d,%d)", UC(a[0]),
1258 		UC(a[1]), UC(a[2]), UC(a[3]), UC(p[0]), UC(p[1]));
1259 	return;
1260 
1261 pasv_error:
1262 	(void) close(pdata);
1263 	pdata = -1;
1264 	perror_reply(425, "Can't open passive connection");
1265 	return;
1266 }
1267 
1268 /*
1269  * Generate unique name for file with basename "local".
1270  * The file named "local" is already known to exist.
1271  * Generates failure reply on error.
1272  */
1273 char *
1274 gunique(local)
1275 	char *local;
1276 {
1277 	static char new[MAXPATHLEN];
1278 	struct stat st;
1279 	char *cp = rindex(local, '/');
1280 	int count = 0;
1281 
1282 	if (cp)
1283 		*cp = '\0';
1284 	if (stat(cp ? local : ".", &st) < 0) {
1285 		perror_reply(553, cp ? local : ".");
1286 		return((char *) 0);
1287 	}
1288 	if (cp)
1289 		*cp = '/';
1290 	(void) strcpy(new, local);
1291 	cp = new + strlen(new);
1292 	*cp++ = '.';
1293 	for (count = 1; count < 100; count++) {
1294 		(void) sprintf(cp, "%d", count);
1295 		if (stat(new, &st) < 0)
1296 			return(new);
1297 	}
1298 	reply(452, "Unique file name cannot be created.");
1299 	return((char *) 0);
1300 }
1301 
1302 /*
1303  * Format and send reply containing system error number.
1304  */
1305 perror_reply(code, string)
1306 	int code;
1307 	char *string;
1308 {
1309 	reply(code, "%s: %s.", string, strerror(errno));
1310 }
1311 
1312 static char *onefile[] = {
1313 	"",
1314 	0
1315 };
1316 
1317 send_file_list(whichfiles)
1318 	char *whichfiles;
1319 {
1320 	struct stat st;
1321 	DIR *dirp = NULL;
1322 	struct dirent *dir;
1323 	FILE *dout = NULL;
1324 	register char **dirlist, *dirname;
1325 	int simple = 0;
1326 	char *strpbrk();
1327 
1328 	if (strpbrk(whichfiles, "~{[*?") != NULL) {
1329 		extern char **ftpglob(), *globerr;
1330 
1331 		globerr = NULL;
1332 		dirlist = ftpglob(whichfiles);
1333 		if (globerr != NULL) {
1334 			reply(550, globerr);
1335 			return;
1336 		} else if (dirlist == NULL) {
1337 			errno = ENOENT;
1338 			perror_reply(550, whichfiles);
1339 			return;
1340 		}
1341 	} else {
1342 		onefile[0] = whichfiles;
1343 		dirlist = onefile;
1344 		simple = 1;
1345 	}
1346 
1347 	if (setjmp(urgcatch)) {
1348 		transflag = 0;
1349 		return;
1350 	}
1351 	while (dirname = *dirlist++) {
1352 		if (stat(dirname, &st) < 0) {
1353 			/*
1354 			 * If user typed "ls -l", etc, and the client
1355 			 * used NLST, do what the user meant.
1356 			 */
1357 			if (dirname[0] == '-' && *dirlist == NULL &&
1358 			    transflag == 0) {
1359 				retrieve("/bin/ls %s", dirname);
1360 				return;
1361 			}
1362 			perror_reply(550, whichfiles);
1363 			if (dout != NULL) {
1364 				(void) fclose(dout);
1365 				transflag = 0;
1366 				data = -1;
1367 				pdata = -1;
1368 			}
1369 			return;
1370 		}
1371 
1372 		if ((st.st_mode&S_IFMT) == S_IFREG) {
1373 			if (dout == NULL) {
1374 				dout = dataconn("file list", (off_t)-1, "w");
1375 				if (dout == NULL)
1376 					return;
1377 				transflag++;
1378 			}
1379 			fprintf(dout, "%s%s\n", dirname,
1380 				type == TYPE_A ? "\r" : "");
1381 			byte_count += strlen(dirname) + 1;
1382 			continue;
1383 		} else if ((st.st_mode&S_IFMT) != S_IFDIR)
1384 			continue;
1385 
1386 		if ((dirp = opendir(dirname)) == NULL)
1387 			continue;
1388 
1389 		while ((dir = readdir(dirp)) != NULL) {
1390 			char nbuf[MAXPATHLEN];
1391 
1392 			if (dir->d_name[0] == '.' && dir->d_namlen == 1)
1393 				continue;
1394 			if (dir->d_name[0] == '.' && dir->d_name[1] == '.' &&
1395 			    dir->d_namlen == 2)
1396 				continue;
1397 
1398 			sprintf(nbuf, "%s/%s", dirname, dir->d_name);
1399 
1400 			/*
1401 			 * We have to do a stat to insure it's
1402 			 * not a directory or special file.
1403 			 */
1404 			if (simple || (stat(nbuf, &st) == 0 &&
1405 			    (st.st_mode&S_IFMT) == S_IFREG)) {
1406 				if (dout == NULL) {
1407 					dout = dataconn("file list", (off_t)-1,
1408 						"w");
1409 					if (dout == NULL)
1410 						return;
1411 					transflag++;
1412 				}
1413 				if (nbuf[0] == '.' && nbuf[1] == '/')
1414 					fprintf(dout, "%s%s\n", &nbuf[2],
1415 						type == TYPE_A ? "\r" : "");
1416 				else
1417 					fprintf(dout, "%s%s\n", nbuf,
1418 						type == TYPE_A ? "\r" : "");
1419 				byte_count += strlen(nbuf) + 1;
1420 			}
1421 		}
1422 		(void) closedir(dirp);
1423 	}
1424 
1425 	if (dout == NULL)
1426 		reply(550, "No files found.");
1427 	else if (ferror(dout) != 0)
1428 		perror_reply(550, "Data connection");
1429 	else
1430 		reply(226, "Transfer complete.");
1431 
1432 	transflag = 0;
1433 	if (dout != NULL)
1434 		(void) fclose(dout);
1435 	data = -1;
1436 	pdata = -1;
1437 }
1438 
1439 #ifdef SETPROCTITLE
1440 /*
1441  * clobber argv so ps will show what we're doing.
1442  * (stolen from sendmail)
1443  * warning, since this is usually started from inetd.conf, it
1444  * often doesn't have much of an environment or arglist to overwrite.
1445  */
1446 
1447 /*VARARGS1*/
1448 setproctitle(fmt, a, b, c)
1449 char *fmt;
1450 {
1451 	register char *p, *bp, ch;
1452 	register int i;
1453 	char buf[BUFSIZ];
1454 
1455 	(void) sprintf(buf, fmt, a, b, c);
1456 
1457 	/* make ps print our process name */
1458 	p = Argv[0];
1459 	*p++ = '-';
1460 
1461 	i = strlen(buf);
1462 	if (i > LastArgv - p - 2) {
1463 		i = LastArgv - p - 2;
1464 		buf[i] = '\0';
1465 	}
1466 	bp = buf;
1467 	while (ch = *bp++)
1468 		if (ch != '\n' && ch != '\r')
1469 			*p++ = ch;
1470 	while (p < LastArgv)
1471 		*p++ = ' ';
1472 }
1473 #endif /* SETPROCTITLE */
1474