xref: /dragonfly/lib/libfetch/ftp.c (revision 1b586c57)
1 /*-
2  * SPDX-License-Identifier: (BSD-3-Clause AND Beerware)
3  *
4  * Copyright (c) 1998-2011 Dag-Erling Smørgrav
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer
12  *    in this position and unchanged.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. The name of the author may not be used to endorse or promote products
17  *    derived from this software without specific prior written permission
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
20  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
22  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
23  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
24  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
28  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29  *
30  * $FreeBSD: head/lib/libfetch/ftp.c 341013 2018-11-27 10:45:14Z des $
31  */
32 
33 /*
34  * Portions of this code were taken from or based on ftpio.c:
35  *
36  * ----------------------------------------------------------------------------
37  * "THE BEER-WARE LICENSE" (Revision 42):
38  * <phk@FreeBSD.org> wrote this file.  As long as you retain this notice you
39  * can do whatever you want with this stuff. If we meet some day, and you think
40  * this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
41  * ----------------------------------------------------------------------------
42  *
43  * Major Changelog:
44  *
45  * Dag-Erling Smørgrav
46  * 9 Jun 1998
47  *
48  * Incorporated into libfetch
49  *
50  * Jordan K. Hubbard
51  * 17 Jan 1996
52  *
53  * Turned inside out. Now returns xfers as new file ids, not as a special
54  * `state' of FTP_t
55  *
56  * $ftpioId: ftpio.c,v 1.30 1998/04/11 07:28:53 phk Exp $
57  *
58  */
59 
60 #include <sys/param.h>
61 #include <sys/socket.h>
62 #include <netinet/in.h>
63 
64 #include <ctype.h>
65 #include <err.h>
66 #include <errno.h>
67 #include <fcntl.h>
68 #include <netdb.h>
69 #include <stdarg.h>
70 #include <stdint.h>
71 #include <stdio.h>
72 #include <stdlib.h>
73 #include <string.h>
74 #include <time.h>
75 #include <unistd.h>
76 
77 #include "fetch.h"
78 #include "common.h"
79 #include "ftperr.h"
80 
81 #define FTP_ANONYMOUS_USER	"anonymous"
82 
83 #define FTP_CONNECTION_ALREADY_OPEN	125
84 #define FTP_OPEN_DATA_CONNECTION	150
85 #define FTP_OK				200
86 #define FTP_FILE_STATUS			213
87 #define FTP_SERVICE_READY		220
88 #define FTP_TRANSFER_COMPLETE		226
89 #define FTP_PASSIVE_MODE		227
90 #define FTP_LPASSIVE_MODE		228
91 #define FTP_EPASSIVE_MODE		229
92 #define FTP_LOGGED_IN			230
93 #define FTP_FILE_ACTION_OK		250
94 #define FTP_DIRECTORY_CREATED		257 /* multiple meanings */
95 #define FTP_FILE_CREATED		257 /* multiple meanings */
96 #define FTP_WORKING_DIRECTORY		257 /* multiple meanings */
97 #define FTP_NEED_PASSWORD		331
98 #define FTP_NEED_ACCOUNT		332
99 #define FTP_FILE_OK			350
100 #define FTP_SYNTAX_ERROR		500
101 #define FTP_PROTOCOL_ERROR		999
102 
103 static int ftp_cmd(conn_t *, const char *, ...) __printflike(2, 3);
104 static struct url cached_host;
105 static conn_t	*cached_connection;
106 
107 #define isftpreply(foo)				\
108 	(isdigit((unsigned char)foo[0]) &&	\
109 	    isdigit((unsigned char)foo[1]) &&	\
110 	    isdigit((unsigned char)foo[2]) &&	\
111 	    (foo[3] == ' ' || foo[3] == '\0'))
112 #define isftpinfo(foo) \
113 	(isdigit((unsigned char)foo[0]) &&	\
114 	    isdigit((unsigned char)foo[1]) &&	\
115 	    isdigit((unsigned char)foo[2]) &&	\
116 	    foo[3] == '-')
117 
118 /*
119  * Translate IPv4 mapped IPv6 address to IPv4 address
120  */
121 static void
unmappedaddr(struct sockaddr_in6 * sin6)122 unmappedaddr(struct sockaddr_in6 *sin6)
123 {
124 	struct sockaddr_in *sin4;
125 	void *addr;
126 	int port;
127 
128 	if (sin6->sin6_family != AF_INET6 ||
129 	    !IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr))
130 		return;
131 	sin4 = (struct sockaddr_in *)sin6;
132 	addr = &sin6->sin6_addr.s6_addr[12];
133 	port = sin6->sin6_port;
134 	memset(sin4, 0, sizeof(struct sockaddr_in));
135 	sin4->sin_addr.s_addr = *(uint32_t *)addr;
136 	sin4->sin_port = port;
137 	sin4->sin_family = AF_INET;
138 	sin4->sin_len = sizeof(struct sockaddr_in);
139 }
140 
141 /*
142  * Get server response
143  */
144 static int
ftp_chkerr(conn_t * conn)145 ftp_chkerr(conn_t *conn)
146 {
147 	if (fetch_getln(conn) == -1) {
148 		fetch_syserr();
149 		return (-1);
150 	}
151 	if (isftpinfo(conn->buf)) {
152 		while (conn->buflen && !isftpreply(conn->buf)) {
153 			if (fetch_getln(conn) == -1) {
154 				fetch_syserr();
155 				return (-1);
156 			}
157 		}
158 	}
159 
160 	while (conn->buflen &&
161 	    isspace((unsigned char)conn->buf[conn->buflen - 1]))
162 		conn->buflen--;
163 	conn->buf[conn->buflen] = '\0';
164 
165 	if (!isftpreply(conn->buf)) {
166 		ftp_seterr(FTP_PROTOCOL_ERROR);
167 		return (-1);
168 	}
169 
170 	conn->err = (conn->buf[0] - '0') * 100
171 	    + (conn->buf[1] - '0') * 10
172 	    + (conn->buf[2] - '0');
173 
174 	return (conn->err);
175 }
176 
177 /*
178  * Send a command and check reply
179  */
180 static int
ftp_cmd(conn_t * conn,const char * fmt,...)181 ftp_cmd(conn_t *conn, const char *fmt, ...)
182 {
183 	va_list ap;
184 	size_t len;
185 	char *msg;
186 	int r;
187 
188 	va_start(ap, fmt);
189 	len = vasprintf(&msg, fmt, ap);
190 	va_end(ap);
191 
192 	if (msg == NULL) {
193 		errno = ENOMEM;
194 		fetch_syserr();
195 		return (-1);
196 	}
197 
198 	r = fetch_putln(conn, msg, len);
199 	free(msg);
200 
201 	if (r == -1) {
202 		fetch_syserr();
203 		return (-1);
204 	}
205 
206 	return (ftp_chkerr(conn));
207 }
208 
209 /*
210  * Return a pointer to the filename part of a path
211  */
212 static const char *
ftp_filename(const char * file,int * len,int * type)213 ftp_filename(const char *file, int *len, int *type)
214 {
215 	const char *s;
216 
217 	if ((s = strrchr(file, '/')) == NULL)
218 		s = file;
219 	else
220 		s = s + 1;
221 	*len = strlen(s);
222 	if (*len > 7 && strncmp(s + *len - 7, ";type=", 6) == 0) {
223 		*type = s[*len - 1];
224 		*len -= 7;
225 	} else {
226 		*type = '\0';
227 	}
228 	return (s);
229 }
230 
231 /*
232  * Get current working directory from the reply to a CWD, PWD or CDUP
233  * command.
234  */
235 static int
ftp_pwd(conn_t * conn,char * pwd,size_t pwdlen)236 ftp_pwd(conn_t *conn, char *pwd, size_t pwdlen)
237 {
238 	char *src, *dst, *end;
239 	int q;
240 
241 	if (conn->err != FTP_WORKING_DIRECTORY &&
242 	    conn->err != FTP_FILE_ACTION_OK)
243 		return (FTP_PROTOCOL_ERROR);
244 	end = conn->buf + conn->buflen;
245 	src = conn->buf + 4;
246 	if (src >= end || *src++ != '"')
247 		return (FTP_PROTOCOL_ERROR);
248 	for (q = 0, dst = pwd; src < end && pwdlen--; ++src) {
249 		if (!q && *src == '"')
250 			q = 1;
251 		else if (q && *src != '"')
252 			break;
253 		else if (q)
254 			*dst++ = '"', q = 0;
255 		else
256 			*dst++ = *src;
257 	}
258 	if (!pwdlen)
259 		return (FTP_PROTOCOL_ERROR);
260 	*dst = '\0';
261 #if 0
262 	DEBUGF("pwd: [%s]\n", pwd);
263 #endif
264 	return (FTP_OK);
265 }
266 
267 /*
268  * Change working directory to the directory that contains the specified
269  * file.
270  */
271 static int
ftp_cwd(conn_t * conn,const char * file)272 ftp_cwd(conn_t *conn, const char *file)
273 {
274 	const char *beg, *end;
275 	char pwd[PATH_MAX];
276 	int e, i, len;
277 
278 	/* If no slashes in name, no need to change dirs. */
279 	if ((end = strrchr(file, '/')) == NULL)
280 		return (0);
281 	if ((e = ftp_cmd(conn, "PWD")) != FTP_WORKING_DIRECTORY ||
282 	    (e = ftp_pwd(conn, pwd, sizeof(pwd))) != FTP_OK) {
283 		ftp_seterr(e);
284 		return (-1);
285 	}
286 	for (;;) {
287 		len = strlen(pwd);
288 
289 		/* Look for a common prefix between PWD and dir to fetch. */
290 		for (i = 0; i <= len && i <= end - file; ++i)
291 			if (pwd[i] != file[i])
292 				break;
293 #if 0
294 		DEBUGF("have: [%.*s|%s]\n", i, pwd, pwd + i);
295 		DEBUGF("want: [%.*s|%s]\n", i, file, file + i);
296 #endif
297 		/* Keep going up a dir until we have a matching prefix. */
298 		if (pwd[i] == '\0' && (file[i - 1] == '/' || file[i] == '/'))
299 			break;
300 		if ((e = ftp_cmd(conn, "CDUP")) != FTP_FILE_ACTION_OK ||
301 		    (e = ftp_cmd(conn, "PWD")) != FTP_WORKING_DIRECTORY ||
302 		    (e = ftp_pwd(conn, pwd, sizeof(pwd))) != FTP_OK) {
303 			ftp_seterr(e);
304 			return (-1);
305 		}
306 	}
307 
308 #ifdef FTP_COMBINE_CWDS
309 	/* Skip leading slashes, even "////". */
310 	for (beg = file + i; beg < end && *beg == '/'; ++beg, ++i)
311 		/* nothing */ ;
312 
313 	/* If there is no trailing dir, we're already there. */
314 	if (beg >= end)
315 		return (0);
316 
317 	/* Change to the directory all in one chunk (e.g., foo/bar/baz). */
318 	e = ftp_cmd(conn, "CWD %.*s", (int)(end - beg), beg);
319 	if (e == FTP_FILE_ACTION_OK)
320 		return (0);
321 #endif /* FTP_COMBINE_CWDS */
322 
323 	/* That didn't work so go back to legacy behavior (multiple CWDs). */
324 	for (beg = file + i; beg < end; beg = file + i + 1) {
325 		while (*beg == '/')
326 			++beg, ++i;
327 		for (++i; file + i < end && file[i] != '/'; ++i)
328 			/* nothing */ ;
329 		e = ftp_cmd(conn, "CWD %.*s", (int)(file + i - beg), beg);
330 		if (e != FTP_FILE_ACTION_OK) {
331 			ftp_seterr(e);
332 			return (-1);
333 		}
334 	}
335 	return (0);
336 }
337 
338 /*
339  * Set transfer mode and data type
340  */
341 static int
ftp_mode_type(conn_t * conn,int mode,int type)342 ftp_mode_type(conn_t *conn, int mode, int type)
343 {
344 	int e;
345 
346 	switch (mode) {
347 	case 0:
348 	case 's':
349 		mode = 'S';
350 	case 'S':
351 		break;
352 	default:
353 		return (FTP_PROTOCOL_ERROR);
354 	}
355 	if ((e = ftp_cmd(conn, "MODE %c", mode)) != FTP_OK) {
356 		if (mode == 'S') {
357 			/*
358 			 * Stream mode is supposed to be the default - so
359 			 * much so that some servers not only do not
360 			 * support any other mode, but do not support the
361 			 * MODE command at all.
362 			 *
363 			 * If "MODE S" fails, it is unlikely that we
364 			 * previously succeeded in setting a different
365 			 * mode.  Therefore, we simply hope that the
366 			 * server is already in the correct mode, and
367 			 * silently ignore the failure.
368 			 */
369 		} else {
370 			return (e);
371 		}
372 	}
373 
374 	switch (type) {
375 	case 0:
376 	case 'i':
377 		type = 'I';
378 	case 'I':
379 		break;
380 	case 'a':
381 		type = 'A';
382 	case 'A':
383 		break;
384 	case 'd':
385 		type = 'D';
386 		/* FALLTHROUGH */
387 	case 'D':
388 		/* can't handle yet */
389 	default:
390 		return (FTP_PROTOCOL_ERROR);
391 	}
392 	if ((e = ftp_cmd(conn, "TYPE %c", type)) != FTP_OK)
393 		return (e);
394 
395 	return (FTP_OK);
396 }
397 
398 /*
399  * Request and parse file stats
400  */
401 static int
ftp_stat(conn_t * conn,const char * file,struct url_stat * us)402 ftp_stat(conn_t *conn, const char *file, struct url_stat *us)
403 {
404 	char *ln;
405 	const char *filename;
406 	int filenamelen, type;
407 	struct tm tm;
408 	time_t t;
409 	int e;
410 
411 	us->size = -1;
412 	us->atime = us->mtime = 0;
413 
414 	filename = ftp_filename(file, &filenamelen, &type);
415 
416 	if ((e = ftp_mode_type(conn, 0, type)) != FTP_OK) {
417 		ftp_seterr(e);
418 		return (-1);
419 	}
420 
421 	e = ftp_cmd(conn, "SIZE %.*s", filenamelen, filename);
422 	if (e != FTP_FILE_STATUS) {
423 		ftp_seterr(e);
424 		return (-1);
425 	}
426 	for (ln = conn->buf + 4; *ln && isspace((unsigned char)*ln); ln++)
427 		/* nothing */ ;
428 	for (us->size = 0; *ln && isdigit((unsigned char)*ln); ln++)
429 		us->size = us->size * 10 + *ln - '0';
430 	if (*ln && !isspace((unsigned char)*ln)) {
431 		ftp_seterr(FTP_PROTOCOL_ERROR);
432 		us->size = -1;
433 		return (-1);
434 	}
435 	if (us->size == 0)
436 		us->size = -1;
437 	DEBUGF("size: [%lld]\n", (long long)us->size);
438 
439 	e = ftp_cmd(conn, "MDTM %.*s", filenamelen, filename);
440 	if (e != FTP_FILE_STATUS) {
441 		ftp_seterr(e);
442 		return (-1);
443 	}
444 	for (ln = conn->buf + 4; *ln && isspace((unsigned char)*ln); ln++)
445 		/* nothing */ ;
446 	switch (strspn(ln, "0123456789")) {
447 	case 14:
448 		break;
449 	case 15:
450 		ln++;
451 		ln[0] = '2';
452 		ln[1] = '0';
453 		break;
454 	default:
455 		ftp_seterr(FTP_PROTOCOL_ERROR);
456 		return (-1);
457 	}
458 	if (sscanf(ln, "%04d%02d%02d%02d%02d%02d",
459 	    &tm.tm_year, &tm.tm_mon, &tm.tm_mday,
460 	    &tm.tm_hour, &tm.tm_min, &tm.tm_sec) != 6) {
461 		ftp_seterr(FTP_PROTOCOL_ERROR);
462 		return (-1);
463 	}
464 	tm.tm_mon--;
465 	tm.tm_year -= 1900;
466 	tm.tm_isdst = -1;
467 	t = timegm(&tm);
468 	if (t == (time_t)-1)
469 		t = time(NULL);
470 	us->mtime = t;
471 	us->atime = t;
472 	DEBUGF("last modified: [%04d-%02d-%02d %02d:%02d:%02d]\n",
473 	    tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
474 	    tm.tm_hour, tm.tm_min, tm.tm_sec);
475 	return (0);
476 }
477 
478 /*
479  * I/O functions for FTP
480  */
481 struct ftpio {
482 	conn_t	*cconn;		/* Control connection */
483 	conn_t	*dconn;		/* Data connection */
484 	int	 dir;		/* Direction */
485 	int	 eof;		/* EOF reached */
486 	int	 err;		/* Error code */
487 };
488 
489 static int	 ftp_readfn(void *, char *, int);
490 static int	 ftp_writefn(void *, const char *, int);
491 static fpos_t	 ftp_seekfn(void *, fpos_t, int);
492 static int	 ftp_closefn(void *);
493 
494 static int
ftp_readfn(void * v,char * buf,int len)495 ftp_readfn(void *v, char *buf, int len)
496 {
497 	struct ftpio *io;
498 	int r;
499 
500 	io = (struct ftpio *)v;
501 	if (io == NULL) {
502 		errno = EBADF;
503 		return (-1);
504 	}
505 	if (io->cconn == NULL || io->dconn == NULL || io->dir == O_WRONLY) {
506 		errno = EBADF;
507 		return (-1);
508 	}
509 	if (io->err) {
510 		errno = io->err;
511 		return (-1);
512 	}
513 	if (io->eof)
514 		return (0);
515 	r = fetch_read(io->dconn, buf, len);
516 	if (r > 0)
517 		return (r);
518 	if (r == 0) {
519 		io->eof = 1;
520 		return (0);
521 	}
522 	if (errno != EINTR)
523 		io->err = errno;
524 	return (-1);
525 }
526 
527 static int
ftp_writefn(void * v,const char * buf,int len)528 ftp_writefn(void *v, const char *buf, int len)
529 {
530 	struct ftpio *io;
531 	int w;
532 
533 	io = (struct ftpio *)v;
534 	if (io == NULL) {
535 		errno = EBADF;
536 		return (-1);
537 	}
538 	if (io->cconn == NULL || io->dconn == NULL || io->dir == O_RDONLY) {
539 		errno = EBADF;
540 		return (-1);
541 	}
542 	if (io->err) {
543 		errno = io->err;
544 		return (-1);
545 	}
546 	w = fetch_write(io->dconn, buf, len);
547 	if (w >= 0)
548 		return (w);
549 	if (errno != EINTR)
550 		io->err = errno;
551 	return (-1);
552 }
553 
554 static fpos_t
ftp_seekfn(void * v,fpos_t pos __unused,int whence __unused)555 ftp_seekfn(void *v, fpos_t pos __unused, int whence __unused)
556 {
557 	struct ftpio *io;
558 
559 	io = (struct ftpio *)v;
560 	if (io == NULL) {
561 		errno = EBADF;
562 		return (-1);
563 	}
564 	errno = ESPIPE;
565 	return (-1);
566 }
567 
568 static int
ftp_closefn(void * v)569 ftp_closefn(void *v)
570 {
571 	struct ftpio *io;
572 	int r;
573 
574 	io = (struct ftpio *)v;
575 	if (io == NULL) {
576 		errno = EBADF;
577 		return (-1);
578 	}
579 	if (io->dir == -1)
580 		return (0);
581 	if (io->cconn == NULL || io->dconn == NULL) {
582 		errno = EBADF;
583 		return (-1);
584 	}
585 	fetch_close(io->dconn);
586 	io->dir = -1;
587 	io->dconn = NULL;
588 	DEBUGF("Waiting for final status\n");
589 	r = ftp_chkerr(io->cconn);
590 	if (io->cconn == cached_connection && io->cconn->ref == 1)
591 		cached_connection = NULL;
592 	fetch_close(io->cconn);
593 	free(io);
594 	return (r == FTP_TRANSFER_COMPLETE) ? 0 : -1;
595 }
596 
597 static FILE *
ftp_setup(conn_t * cconn,conn_t * dconn,int mode)598 ftp_setup(conn_t *cconn, conn_t *dconn, int mode)
599 {
600 	struct ftpio *io;
601 	FILE *f;
602 
603 	if (cconn == NULL || dconn == NULL)
604 		return (NULL);
605 	if ((io = malloc(sizeof(*io))) == NULL)
606 		return (NULL);
607 	io->cconn = cconn;
608 	io->dconn = dconn;
609 	io->dir = mode;
610 	io->eof = io->err = 0;
611 	f = funopen(io, ftp_readfn, ftp_writefn, ftp_seekfn, ftp_closefn);
612 	if (f == NULL)
613 		free(io);
614 	return (f);
615 }
616 
617 /*
618  * Transfer file
619  */
620 static FILE *
ftp_transfer(conn_t * conn,const char * oper,const char * file,int mode,off_t offset,const char * flags)621 ftp_transfer(conn_t *conn, const char *oper, const char *file,
622     int mode, off_t offset, const char *flags)
623 {
624 	struct sockaddr_storage sa;
625 	struct sockaddr_in6 *sin6;
626 	struct sockaddr_in *sin4;
627 	const char *bindaddr;
628 	const char *filename;
629 	int filenamelen, type;
630 	int low, pasv, verbose;
631 	int e, sd = -1;
632 	socklen_t l;
633 	char *s;
634 	FILE *df;
635 
636 	/* check flags */
637 	low = CHECK_FLAG('l');
638 	pasv = CHECK_FLAG('p') || !CHECK_FLAG('P');
639 	verbose = CHECK_FLAG('v');
640 
641 	/* passive mode */
642 	if ((s = getenv("FTP_PASSIVE_MODE")) != NULL)
643 		pasv = (strncasecmp(s, "no", 2) != 0);
644 
645 	/* isolate filename */
646 	filename = ftp_filename(file, &filenamelen, &type);
647 
648 	/* set transfer mode and data type */
649 	if ((e = ftp_mode_type(conn, 0, type)) != FTP_OK)
650 		goto ouch;
651 
652 	/* find our own address, bind, and listen */
653 	l = sizeof(sa);
654 	if (getsockname(conn->sd, (struct sockaddr *)&sa, &l) == -1)
655 		goto sysouch;
656 	if (sa.ss_family == AF_INET6)
657 		unmappedaddr((struct sockaddr_in6 *)&sa);
658 
659 	/* open data socket */
660 	if ((sd = socket(sa.ss_family, SOCK_STREAM, IPPROTO_TCP)) == -1) {
661 		fetch_syserr();
662 		return (NULL);
663 	}
664 
665 	if (pasv) {
666 		u_char addr[64];
667 		char *ln, *p;
668 		unsigned int i;
669 		int port;
670 
671 		/* send PASV command */
672 		if (verbose)
673 			fetch_info("setting passive mode");
674 		switch (sa.ss_family) {
675 		case AF_INET:
676 			if ((e = ftp_cmd(conn, "PASV")) != FTP_PASSIVE_MODE)
677 				goto ouch;
678 			break;
679 		case AF_INET6:
680 			if ((e = ftp_cmd(conn, "EPSV")) != FTP_EPASSIVE_MODE) {
681 				if (e == -1)
682 					goto ouch;
683 				if ((e = ftp_cmd(conn, "LPSV")) !=
684 				    FTP_LPASSIVE_MODE)
685 					goto ouch;
686 			}
687 			break;
688 		default:
689 			e = FTP_PROTOCOL_ERROR; /* XXX: error code should be prepared */
690 			goto ouch;
691 		}
692 
693 		/*
694 		 * Find address and port number. The reply to the PASV command
695 		 * is IMHO the one and only weak point in the FTP protocol.
696 		 */
697 		ln = conn->buf;
698 		switch (e) {
699 		case FTP_PASSIVE_MODE:
700 		case FTP_LPASSIVE_MODE:
701 			for (p = ln + 3; *p && !isdigit((unsigned char)*p); p++)
702 				/* nothing */ ;
703 			if (!*p) {
704 				e = FTP_PROTOCOL_ERROR;
705 				goto ouch;
706 			}
707 			l = (e == FTP_PASSIVE_MODE ? 6 : 21);
708 			for (i = 0; *p && i < l; i++, p++)
709 				addr[i] = strtol(p, &p, 10);
710 			if (i < l) {
711 				e = FTP_PROTOCOL_ERROR;
712 				goto ouch;
713 			}
714 			break;
715 		case FTP_EPASSIVE_MODE:
716 			for (p = ln + 3; *p && *p != '('; p++)
717 				/* nothing */ ;
718 			if (!*p) {
719 				e = FTP_PROTOCOL_ERROR;
720 				goto ouch;
721 			}
722 			++p;
723 			if (sscanf(p, "%c%c%c%d%c", &addr[0], &addr[1], &addr[2],
724 				&port, &addr[3]) != 5 ||
725 			    addr[0] != addr[1] ||
726 			    addr[0] != addr[2] || addr[0] != addr[3]) {
727 				e = FTP_PROTOCOL_ERROR;
728 				goto ouch;
729 			}
730 			break;
731 		}
732 
733 		/* seek to required offset */
734 		if (offset)
735 			if (ftp_cmd(conn, "REST %lu", (u_long)offset) != FTP_FILE_OK)
736 				goto sysouch;
737 
738 		/* construct sockaddr for data socket */
739 		l = sizeof(sa);
740 		if (getpeername(conn->sd, (struct sockaddr *)&sa, &l) == -1)
741 			goto sysouch;
742 		if (sa.ss_family == AF_INET6)
743 			unmappedaddr((struct sockaddr_in6 *)&sa);
744 		switch (sa.ss_family) {
745 		case AF_INET6:
746 			sin6 = (struct sockaddr_in6 *)&sa;
747 			if (e == FTP_EPASSIVE_MODE)
748 				sin6->sin6_port = htons(port);
749 			else {
750 				memcpy(&sin6->sin6_addr, addr + 2, 16);
751 				memcpy(&sin6->sin6_port, addr + 19, 2);
752 			}
753 			break;
754 		case AF_INET:
755 			sin4 = (struct sockaddr_in *)&sa;
756 			if (e == FTP_EPASSIVE_MODE)
757 				sin4->sin_port = htons(port);
758 			else {
759 				memcpy(&sin4->sin_addr, addr, 4);
760 				memcpy(&sin4->sin_port, addr + 4, 2);
761 			}
762 			break;
763 		default:
764 			e = FTP_PROTOCOL_ERROR; /* XXX: error code should be prepared */
765 			break;
766 		}
767 
768 		/* connect to data port */
769 		if (verbose)
770 			fetch_info("opening data connection");
771 		bindaddr = getenv("FETCH_BIND_ADDRESS");
772 		if (bindaddr != NULL && *bindaddr != '\0' &&
773 		    (e = fetch_bind(sd, sa.ss_family, bindaddr)) != 0)
774 			goto ouch;
775 		if (connect(sd, (struct sockaddr *)&sa, sa.ss_len) == -1)
776 			goto sysouch;
777 
778 		/* make the server initiate the transfer */
779 		if (verbose)
780 			fetch_info("initiating transfer");
781 		e = ftp_cmd(conn, "%s %.*s", oper, filenamelen, filename);
782 		if (e != FTP_CONNECTION_ALREADY_OPEN && e != FTP_OPEN_DATA_CONNECTION)
783 			goto ouch;
784 
785 	} else {
786 		u_int32_t a;
787 		u_short p;
788 		int arg, d;
789 		char *ap;
790 		char hname[INET6_ADDRSTRLEN];
791 
792 		switch (sa.ss_family) {
793 		case AF_INET6:
794 			((struct sockaddr_in6 *)&sa)->sin6_port = 0;
795 #ifdef IPV6_PORTRANGE
796 			arg = low ? IPV6_PORTRANGE_DEFAULT : IPV6_PORTRANGE_HIGH;
797 			if (setsockopt(sd, IPPROTO_IPV6, IPV6_PORTRANGE,
798 				(char *)&arg, sizeof(arg)) == -1)
799 				goto sysouch;
800 #endif
801 			break;
802 		case AF_INET:
803 			((struct sockaddr_in *)&sa)->sin_port = 0;
804 			arg = low ? IP_PORTRANGE_DEFAULT : IP_PORTRANGE_HIGH;
805 			if (setsockopt(sd, IPPROTO_IP, IP_PORTRANGE,
806 				(char *)&arg, sizeof(arg)) == -1)
807 				goto sysouch;
808 			break;
809 		}
810 		if (verbose)
811 			fetch_info("binding data socket");
812 		if (bind(sd, (struct sockaddr *)&sa, sa.ss_len) == -1)
813 			goto sysouch;
814 		if (listen(sd, 1) == -1)
815 			goto sysouch;
816 
817 		/* find what port we're on and tell the server */
818 		if (getsockname(sd, (struct sockaddr *)&sa, &l) == -1)
819 			goto sysouch;
820 		switch (sa.ss_family) {
821 		case AF_INET:
822 			sin4 = (struct sockaddr_in *)&sa;
823 			a = ntohl(sin4->sin_addr.s_addr);
824 			p = ntohs(sin4->sin_port);
825 			e = ftp_cmd(conn, "PORT %d,%d,%d,%d,%d,%d",
826 			    (a >> 24) & 0xff, (a >> 16) & 0xff,
827 			    (a >> 8) & 0xff, a & 0xff,
828 			    (p >> 8) & 0xff, p & 0xff);
829 			break;
830 		case AF_INET6:
831 #define UC(b)	(((int)b)&0xff)
832 			e = -1;
833 			sin6 = (struct sockaddr_in6 *)&sa;
834 			sin6->sin6_scope_id = 0;
835 			if (getnameinfo((struct sockaddr *)&sa, sa.ss_len,
836 				hname, sizeof(hname),
837 				NULL, 0, NI_NUMERICHOST) == 0) {
838 				e = ftp_cmd(conn, "EPRT |%d|%s|%d|", 2, hname,
839 				    htons(sin6->sin6_port));
840 				if (e == -1)
841 					goto ouch;
842 			}
843 			if (e != FTP_OK) {
844 				ap = (char *)&sin6->sin6_addr;
845 				e = ftp_cmd(conn,
846 				    "LPRT %d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d",
847 				    6, 16,
848 				    UC(ap[0]), UC(ap[1]), UC(ap[2]), UC(ap[3]),
849 				    UC(ap[4]), UC(ap[5]), UC(ap[6]), UC(ap[7]),
850 				    UC(ap[8]), UC(ap[9]), UC(ap[10]), UC(ap[11]),
851 				    UC(ap[12]), UC(ap[13]), UC(ap[14]), UC(ap[15]),
852 				    2,
853 				    (ntohs(sin6->sin6_port) >> 8) & 0xff,
854 				    ntohs(sin6->sin6_port)        & 0xff);
855 			}
856 			break;
857 		default:
858 			e = FTP_PROTOCOL_ERROR; /* XXX: error code should be prepared */
859 			goto ouch;
860 		}
861 		if (e != FTP_OK)
862 			goto ouch;
863 
864 		/* seek to required offset */
865 		if (offset)
866 			if (ftp_cmd(conn, "REST %ju", (uintmax_t)offset) != FTP_FILE_OK)
867 				goto sysouch;
868 
869 		/* make the server initiate the transfer */
870 		if (verbose)
871 			fetch_info("initiating transfer");
872 		e = ftp_cmd(conn, "%s %.*s", oper, filenamelen, filename);
873 		if (e != FTP_CONNECTION_ALREADY_OPEN && e != FTP_OPEN_DATA_CONNECTION)
874 			goto ouch;
875 
876 		/* accept the incoming connection and go to town */
877 		if ((d = accept(sd, NULL, NULL)) == -1)
878 			goto sysouch;
879 		close(sd);
880 		sd = d;
881 	}
882 
883 	if ((df = ftp_setup(conn, fetch_reopen(sd), mode)) == NULL)
884 		goto sysouch;
885 	return (df);
886 
887 sysouch:
888 	fetch_syserr();
889 	if (sd >= 0)
890 		close(sd);
891 	return (NULL);
892 
893 ouch:
894 	if (e != -1)
895 		ftp_seterr(e);
896 	if (sd >= 0)
897 		close(sd);
898 	return (NULL);
899 }
900 
901 /*
902  * Authenticate
903  */
904 static int
ftp_authenticate(conn_t * conn,struct url * url,struct url * purl)905 ftp_authenticate(conn_t *conn, struct url *url, struct url *purl)
906 {
907 	const char *user, *pwd, *logname;
908 	char pbuf[MAXHOSTNAMELEN + MAXLOGNAME + 1];
909 	int e, len;
910 
911 	/* XXX FTP_AUTH, and maybe .netrc */
912 
913 	/* send user name and password */
914 	if (url->user[0] == '\0')
915 		fetch_netrc_auth(url);
916 	user = url->user;
917 	if (*user == '\0')
918 		if ((user = getenv("FTP_LOGIN")) != NULL)
919 			DEBUGF("FTP_LOGIN=%s\n", user);
920 	if (user == NULL || *user == '\0')
921 		user = FTP_ANONYMOUS_USER;
922 	if (purl && url->port == fetch_default_port(url->scheme))
923 		e = ftp_cmd(conn, "USER %s@%s", user, url->host);
924 	else if (purl)
925 		e = ftp_cmd(conn, "USER %s@%s@%d", user, url->host, url->port);
926 	else
927 		e = ftp_cmd(conn, "USER %s", user);
928 
929 	/* did the server request a password? */
930 	if (e == FTP_NEED_PASSWORD) {
931 		pwd = url->pwd;
932 		if (*pwd == '\0')
933 			if ((pwd = getenv("FTP_PASSWORD")) != NULL)
934 				DEBUGF("FTP_PASSWORD=%s\n", pwd);
935 		if (pwd == NULL || *pwd == '\0') {
936 			if ((logname = getlogin()) == NULL)
937 				logname = FTP_ANONYMOUS_USER;
938 			if ((len = snprintf(pbuf, MAXLOGNAME + 1, "%s@", logname)) < 0)
939 				len = 0;
940 			else if (len > MAXLOGNAME)
941 				len = MAXLOGNAME;
942 			gethostname(pbuf + len, sizeof(pbuf) - len);
943 			pwd = pbuf;
944 		}
945 		e = ftp_cmd(conn, "PASS %s", pwd);
946 	}
947 
948 	return (e);
949 }
950 
951 /*
952  * Log on to FTP server
953  */
954 static conn_t *
ftp_connect(struct url * url,struct url * purl,const char * flags)955 ftp_connect(struct url *url, struct url *purl, const char *flags)
956 {
957 	conn_t *conn;
958 	int e, direct, verbose;
959 #ifdef INET6
960 	int af = AF_UNSPEC;
961 #else
962 	int af = AF_INET;
963 #endif
964 
965 	direct = CHECK_FLAG('d');
966 	verbose = CHECK_FLAG('v');
967 	if (CHECK_FLAG('4'))
968 		af = AF_INET;
969 	else if (CHECK_FLAG('6'))
970 		af = AF_INET6;
971 
972 	if (direct)
973 		purl = NULL;
974 
975 	/* check for proxy */
976 	if (purl) {
977 		/* XXX proxy authentication! */
978 		conn = fetch_connect(purl->host, purl->port, af, verbose);
979 	} else {
980 		/* no proxy, go straight to target */
981 		conn = fetch_connect(url->host, url->port, af, verbose);
982 		purl = NULL;
983 	}
984 
985 	/* check connection */
986 	if (conn == NULL)
987 		/* fetch_connect() has already set an error code */
988 		return (NULL);
989 
990 	/* expect welcome message */
991 	if ((e = ftp_chkerr(conn)) != FTP_SERVICE_READY)
992 		goto fouch;
993 
994 	/* authenticate */
995 	if ((e = ftp_authenticate(conn, url, purl)) != FTP_LOGGED_IN)
996 		goto fouch;
997 
998 	/* TODO: Request extended features supported, if any (RFC 3659). */
999 
1000 	/* done */
1001 	return (conn);
1002 
1003 fouch:
1004 	if (e != -1)
1005 		ftp_seterr(e);
1006 	fetch_close(conn);
1007 	return (NULL);
1008 }
1009 
1010 /*
1011  * Disconnect from server
1012  */
1013 static void
ftp_disconnect(conn_t * conn)1014 ftp_disconnect(conn_t *conn)
1015 {
1016 	(void)ftp_cmd(conn, "QUIT");
1017 	if (conn == cached_connection && conn->ref == 1)
1018 		cached_connection = NULL;
1019 	fetch_close(conn);
1020 }
1021 
1022 /*
1023  * Check if we're already connected
1024  */
1025 static int
ftp_isconnected(struct url * url)1026 ftp_isconnected(struct url *url)
1027 {
1028 	return (cached_connection
1029 	    && (strcmp(url->host, cached_host.host) == 0)
1030 	    && (strcmp(url->user, cached_host.user) == 0)
1031 	    && (strcmp(url->pwd, cached_host.pwd) == 0)
1032 	    && (url->port == cached_host.port));
1033 }
1034 
1035 /*
1036  * Check the cache, reconnect if no luck
1037  */
1038 static conn_t *
ftp_cached_connect(struct url * url,struct url * purl,const char * flags)1039 ftp_cached_connect(struct url *url, struct url *purl, const char *flags)
1040 {
1041 	conn_t *conn;
1042 	int e;
1043 
1044 	/* set default port */
1045 	if (!url->port)
1046 		url->port = fetch_default_port(url->scheme);
1047 
1048 	/* try to use previously cached connection */
1049 	if (ftp_isconnected(url)) {
1050 		e = ftp_cmd(cached_connection, "NOOP");
1051 		if (e == FTP_OK || e == FTP_SYNTAX_ERROR)
1052 			return (fetch_ref(cached_connection));
1053 	}
1054 
1055 	/* connect to server */
1056 	if ((conn = ftp_connect(url, purl, flags)) == NULL)
1057 		return (NULL);
1058 	if (cached_connection)
1059 		ftp_disconnect(cached_connection);
1060 	cached_connection = fetch_ref(conn);
1061 	memcpy(&cached_host, url, sizeof(*url));
1062 	return (conn);
1063 }
1064 
1065 /*
1066  * Check the proxy settings
1067  */
1068 static struct url *
ftp_get_proxy(struct url * url,const char * flags)1069 ftp_get_proxy(struct url * url, const char *flags)
1070 {
1071 	struct url *purl;
1072 	char *p;
1073 
1074 	if (flags != NULL && strchr(flags, 'd') != NULL)
1075 		return (NULL);
1076 	if (fetch_no_proxy_match(url->host))
1077 		return (NULL);
1078 	if (((p = getenv("FTP_PROXY")) || (p = getenv("ftp_proxy")) ||
1079 		(p = getenv("HTTP_PROXY")) || (p = getenv("http_proxy"))) &&
1080 	    *p && (purl = fetchParseURL(p)) != NULL) {
1081 		if (!*purl->scheme) {
1082 			if (getenv("FTP_PROXY") || getenv("ftp_proxy"))
1083 				strcpy(purl->scheme, SCHEME_FTP);
1084 			else
1085 				strcpy(purl->scheme, SCHEME_HTTP);
1086 		}
1087 		if (!purl->port)
1088 			purl->port = fetch_default_proxy_port(purl->scheme);
1089 		if (strcmp(purl->scheme, SCHEME_FTP) == 0 ||
1090 		    strcmp(purl->scheme, SCHEME_HTTP) == 0)
1091 			return (purl);
1092 		fetchFreeURL(purl);
1093 	}
1094 	return (NULL);
1095 }
1096 
1097 /*
1098  * Process an FTP request
1099  */
1100 FILE *
ftp_request(struct url * url,const char * op,struct url_stat * us,struct url * purl,const char * flags)1101 ftp_request(struct url *url, const char *op, struct url_stat *us,
1102     struct url *purl, const char *flags)
1103 {
1104 	conn_t *conn;
1105 	int oflag;
1106 
1107 	/* check if we should use HTTP instead */
1108 	if (purl && (strcmp(purl->scheme, SCHEME_HTTP) == 0 ||
1109 	    strcmp(purl->scheme, SCHEME_HTTPS) == 0)) {
1110 		if (strcmp(op, "STAT") == 0)
1111 			return (http_request(url, "HEAD", us, purl, flags));
1112 		else if (strcmp(op, "RETR") == 0)
1113 			return (http_request(url, "GET", us, purl, flags));
1114 		/*
1115 		 * Our HTTP code doesn't support PUT requests yet, so try
1116 		 * a direct connection.
1117 		 */
1118 	}
1119 
1120 	/* connect to server */
1121 	conn = ftp_cached_connect(url, purl, flags);
1122 	if (purl)
1123 		fetchFreeURL(purl);
1124 	if (conn == NULL)
1125 		return (NULL);
1126 
1127 	/* change directory */
1128 	if (ftp_cwd(conn, url->doc) == -1)
1129 		goto errsock;
1130 
1131 	/* stat file */
1132 	if (us && ftp_stat(conn, url->doc, us) == -1
1133 	    && fetchLastErrCode != FETCH_PROTO
1134 	    && fetchLastErrCode != FETCH_UNAVAIL)
1135 		goto errsock;
1136 
1137 	/* just a stat */
1138 	if (strcmp(op, "STAT") == 0) {
1139 		--conn->ref;
1140 		ftp_disconnect(conn);
1141 		return (FILE *)1; /* bogus return value */
1142 	}
1143 	if (strcmp(op, "STOR") == 0 || strcmp(op, "APPE") == 0)
1144 		oflag = O_WRONLY;
1145 	else
1146 		oflag = O_RDONLY;
1147 
1148 	/* initiate the transfer */
1149 	return (ftp_transfer(conn, op, url->doc, oflag, url->offset, flags));
1150 
1151 errsock:
1152 	ftp_disconnect(conn);
1153 	return (NULL);
1154 }
1155 
1156 /*
1157  * Get and stat file
1158  */
1159 FILE *
fetchXGetFTP(struct url * url,struct url_stat * us,const char * flags)1160 fetchXGetFTP(struct url *url, struct url_stat *us, const char *flags)
1161 {
1162 	return (ftp_request(url, "RETR", us, ftp_get_proxy(url, flags), flags));
1163 }
1164 
1165 /*
1166  * Get file
1167  */
1168 FILE *
fetchGetFTP(struct url * url,const char * flags)1169 fetchGetFTP(struct url *url, const char *flags)
1170 {
1171 	return (fetchXGetFTP(url, NULL, flags));
1172 }
1173 
1174 /*
1175  * Put file
1176  */
1177 FILE *
fetchPutFTP(struct url * url,const char * flags)1178 fetchPutFTP(struct url *url, const char *flags)
1179 {
1180 	return (ftp_request(url, CHECK_FLAG('a') ? "APPE" : "STOR", NULL,
1181 	    ftp_get_proxy(url, flags), flags));
1182 }
1183 
1184 /*
1185  * Get file stats
1186  */
1187 int
fetchStatFTP(struct url * url,struct url_stat * us,const char * flags)1188 fetchStatFTP(struct url *url, struct url_stat *us, const char *flags)
1189 {
1190 	FILE *f;
1191 
1192 	f = ftp_request(url, "STAT", us, ftp_get_proxy(url, flags), flags);
1193 	if (f == NULL)
1194 		return (-1);
1195 	/*
1196 	 * When op is "STAT", ftp_request() will return either NULL or
1197 	 * (FILE *)1, never a valid FILE *, so we mustn't fclose(f) before
1198 	 * returning, as it would cause a segfault.
1199 	 */
1200 	return (0);
1201 }
1202 
1203 /*
1204  * List a directory
1205  */
1206 struct url_ent *
fetchListFTP(struct url * url __unused,const char * flags __unused)1207 fetchListFTP(struct url *url __unused, const char *flags __unused)
1208 {
1209 	warnx("fetchListFTP(): not implemented");
1210 	return (NULL);
1211 }
1212