Busybox: Upgrade to 1.21.1 (stable). lsof active.
[tomato.git] / release / src / router / busybox / networking / ftpd.c
blob33db964fa46c465b72bda6fa75c65adee1873ee0
1 /* vi: set sw=4 ts=4: */
2 /*
3 * Simple FTP daemon, based on vsftpd 2.0.7 (written by Chris Evans)
5 * Author: Adam Tkac <vonsch@gmail.com>
7 * Licensed under GPLv2, see file LICENSE in this source tree.
9 * Only subset of FTP protocol is implemented but vast majority of clients
10 * should not have any problem.
12 * You have to run this daemon via inetd.
15 //usage:#define ftpd_trivial_usage
16 //usage: "[-wvS] [-t N] [-T N] [DIR]"
17 //usage:#define ftpd_full_usage "\n\n"
18 //usage: "Anonymous FTP server\n"
19 //usage: "\n"
20 //usage: "ftpd should be used as an inetd service.\n"
21 //usage: "ftpd's line for inetd.conf:\n"
22 //usage: " 21 stream tcp nowait root ftpd ftpd /files/to/serve\n"
23 //usage: "It also can be ran from tcpsvd:\n"
24 //usage: " tcpsvd -vE 0.0.0.0 21 ftpd /files/to/serve\n"
25 //usage: "\n -w Allow upload"
26 //usage: "\n -v Log errors to stderr. -vv: verbose log"
27 //usage: "\n -S Log errors to syslog. -SS: verbose log"
28 //usage: "\n -t,-T Idle and absolute timeouts"
29 //usage: "\n DIR Change root to this directory"
31 #include "libbb.h"
32 #include <syslog.h>
33 #include <netinet/tcp.h>
35 #define FTP_DATACONN 150
36 #define FTP_NOOPOK 200
37 #define FTP_TYPEOK 200
38 #define FTP_PORTOK 200
39 #define FTP_STRUOK 200
40 #define FTP_MODEOK 200
41 #define FTP_ALLOOK 202
42 #define FTP_STATOK 211
43 #define FTP_STATFILE_OK 213
44 #define FTP_HELP 214
45 #define FTP_SYSTOK 215
46 #define FTP_GREET 220
47 #define FTP_GOODBYE 221
48 #define FTP_TRANSFEROK 226
49 #define FTP_PASVOK 227
50 /*#define FTP_EPRTOK 228*/
51 #define FTP_EPSVOK 229
52 #define FTP_LOGINOK 230
53 #define FTP_CWDOK 250
54 #define FTP_RMDIROK 250
55 #define FTP_DELEOK 250
56 #define FTP_RENAMEOK 250
57 #define FTP_PWDOK 257
58 #define FTP_MKDIROK 257
59 #define FTP_GIVEPWORD 331
60 #define FTP_RESTOK 350
61 #define FTP_RNFROK 350
62 #define FTP_TIMEOUT 421
63 #define FTP_BADSENDCONN 425
64 #define FTP_BADSENDNET 426
65 #define FTP_BADSENDFILE 451
66 #define FTP_BADCMD 500
67 #define FTP_COMMANDNOTIMPL 502
68 #define FTP_NEEDUSER 503
69 #define FTP_NEEDRNFR 503
70 #define FTP_BADSTRU 504
71 #define FTP_BADMODE 504
72 #define FTP_LOGINERR 530
73 #define FTP_FILEFAIL 550
74 #define FTP_NOPERM 550
75 #define FTP_UPLOADFAIL 553
77 #define STR1(s) #s
78 #define STR(s) STR1(s)
80 /* Convert a constant to 3-digit string, packed into uint32_t */
81 enum {
82 /* Shift for Nth decimal digit */
83 SHIFT2 = 0 * BB_LITTLE_ENDIAN + 24 * BB_BIG_ENDIAN,
84 SHIFT1 = 8 * BB_LITTLE_ENDIAN + 16 * BB_BIG_ENDIAN,
85 SHIFT0 = 16 * BB_LITTLE_ENDIAN + 8 * BB_BIG_ENDIAN,
86 /* And for 4th position (space) */
87 SHIFTsp = 24 * BB_LITTLE_ENDIAN + 0 * BB_BIG_ENDIAN,
89 #define STRNUM32(s) (uint32_t)(0 \
90 | (('0' + ((s) / 1 % 10)) << SHIFT0) \
91 | (('0' + ((s) / 10 % 10)) << SHIFT1) \
92 | (('0' + ((s) / 100 % 10)) << SHIFT2) \
94 #define STRNUM32sp(s) (uint32_t)(0 \
95 | (' ' << SHIFTsp) \
96 | (('0' + ((s) / 1 % 10)) << SHIFT0) \
97 | (('0' + ((s) / 10 % 10)) << SHIFT1) \
98 | (('0' + ((s) / 100 % 10)) << SHIFT2) \
101 #define MSG_OK "Operation successful\r\n"
102 #define MSG_ERR "Error\r\n"
104 struct globals {
105 int pasv_listen_fd;
106 #if !BB_MMU
107 int root_fd;
108 #endif
109 int local_file_fd;
110 unsigned end_time;
111 unsigned timeout;
112 unsigned verbose;
113 off_t local_file_pos;
114 off_t restart_pos;
115 len_and_sockaddr *local_addr;
116 len_and_sockaddr *port_addr;
117 char *ftp_cmd;
118 char *ftp_arg;
119 #if ENABLE_FEATURE_FTP_WRITE
120 char *rnfr_filename;
121 #endif
122 /* We need these aligned to uint32_t */
123 char msg_ok [(sizeof("NNN " MSG_OK ) + 3) & 0xfffc];
124 char msg_err[(sizeof("NNN " MSG_ERR) + 3) & 0xfffc];
125 } FIX_ALIASING;
126 #define G (*(struct globals*)&bb_common_bufsiz1)
127 #define INIT_G() do { \
128 /* Moved to main */ \
129 /*strcpy(G.msg_ok + 4, MSG_OK );*/ \
130 /*strcpy(G.msg_err + 4, MSG_ERR);*/ \
131 } while (0)
134 static char *
135 escape_text(const char *prepend, const char *str, unsigned escapee)
137 unsigned retlen, remainlen, chunklen;
138 char *ret, *found;
139 char append;
141 append = (char)escapee;
142 escapee >>= 8;
144 remainlen = strlen(str);
145 retlen = strlen(prepend);
146 ret = xmalloc(retlen + remainlen * 2 + 1 + 1);
147 strcpy(ret, prepend);
149 for (;;) {
150 found = strchrnul(str, escapee);
151 chunklen = found - str + 1;
153 /* Copy chunk up to and including escapee (or NUL) to ret */
154 memcpy(ret + retlen, str, chunklen);
155 retlen += chunklen;
157 if (*found == '\0') {
158 /* It wasn't escapee, it was NUL! */
159 ret[retlen - 1] = append; /* replace NUL */
160 ret[retlen] = '\0'; /* add NUL */
161 break;
163 ret[retlen++] = escapee; /* duplicate escapee */
164 str = found + 1;
166 return ret;
169 /* Returns strlen as a bonus */
170 static unsigned
171 replace_char(char *str, char from, char to)
173 char *p = str;
174 while (*p) {
175 if (*p == from)
176 *p = to;
177 p++;
179 return p - str;
182 static void
183 verbose_log(const char *str)
185 bb_error_msg("%.*s", (int)strcspn(str, "\r\n"), str);
188 /* NB: status_str is char[4] packed into uint32_t */
189 static void
190 cmdio_write(uint32_t status_str, const char *str)
192 char *response;
193 int len;
195 /* FTP uses telnet protocol for command link.
196 * In telnet, 0xff is an escape char, and needs to be escaped: */
197 response = escape_text((char *) &status_str, str, (0xff << 8) + '\r');
199 /* FTP sends embedded LFs as NULs */
200 len = replace_char(response, '\n', '\0');
202 response[len++] = '\n'; /* tack on trailing '\n' */
203 xwrite(STDOUT_FILENO, response, len);
204 if (G.verbose > 1)
205 verbose_log(response);
206 free(response);
209 static void
210 cmdio_write_ok(unsigned status)
212 *(uint32_t *) G.msg_ok = status;
213 xwrite(STDOUT_FILENO, G.msg_ok, sizeof("NNN " MSG_OK) - 1);
214 if (G.verbose > 1)
215 verbose_log(G.msg_ok);
217 #define WRITE_OK(a) cmdio_write_ok(STRNUM32sp(a))
219 /* TODO: output strerr(errno) if errno != 0? */
220 static void
221 cmdio_write_error(unsigned status)
223 *(uint32_t *) G.msg_err = status;
224 xwrite(STDOUT_FILENO, G.msg_err, sizeof("NNN " MSG_ERR) - 1);
225 if (G.verbose > 0)
226 verbose_log(G.msg_err);
228 #define WRITE_ERR(a) cmdio_write_error(STRNUM32sp(a))
230 static void
231 cmdio_write_raw(const char *p_text)
233 xwrite_str(STDOUT_FILENO, p_text);
234 if (G.verbose > 1)
235 verbose_log(p_text);
238 static void
239 timeout_handler(int sig UNUSED_PARAM)
241 off_t pos;
242 int sv_errno = errno;
244 if ((int)(monotonic_sec() - G.end_time) >= 0)
245 goto timed_out;
247 if (!G.local_file_fd)
248 goto timed_out;
250 pos = xlseek(G.local_file_fd, 0, SEEK_CUR);
251 if (pos == G.local_file_pos)
252 goto timed_out;
253 G.local_file_pos = pos;
255 alarm(G.timeout);
256 errno = sv_errno;
257 return;
259 timed_out:
260 cmdio_write_raw(STR(FTP_TIMEOUT)" Timeout\r\n");
261 /* TODO: do we need to abort (as opposed to usual shutdown) data transfer? */
262 exit(1);
265 /* Simple commands */
267 static void
268 handle_pwd(void)
270 char *cwd, *response;
272 cwd = xrealloc_getcwd_or_warn(NULL);
273 if (cwd == NULL)
274 cwd = xstrdup("");
276 /* We have to promote each " to "" */
277 response = escape_text(" \"", cwd, ('"' << 8) + '"');
278 free(cwd);
279 cmdio_write(STRNUM32(FTP_PWDOK), response);
280 free(response);
283 static void
284 handle_cwd(void)
286 if (!G.ftp_arg || chdir(G.ftp_arg) != 0) {
287 WRITE_ERR(FTP_FILEFAIL);
288 return;
290 WRITE_OK(FTP_CWDOK);
293 static void
294 handle_cdup(void)
296 G.ftp_arg = (char*)"..";
297 handle_cwd();
300 static void
301 handle_stat(void)
303 cmdio_write_raw(STR(FTP_STATOK)"-Server status:\r\n"
304 " TYPE: BINARY\r\n"
305 STR(FTP_STATOK)" Ok\r\n");
308 /* Examples of HELP and FEAT:
309 # nc -vvv ftp.kernel.org 21
310 ftp.kernel.org (130.239.17.4:21) open
311 220 Welcome to ftp.kernel.org.
312 FEAT
313 211-Features:
314 EPRT
315 EPSV
316 MDTM
317 PASV
318 REST STREAM
319 SIZE
320 TVFS
321 UTF8
322 211 End
323 HELP
324 214-The following commands are recognized.
325 ABOR ACCT ALLO APPE CDUP CWD DELE EPRT EPSV FEAT HELP LIST MDTM MKD
326 MODE NLST NOOP OPTS PASS PASV PORT PWD QUIT REIN REST RETR RMD RNFR
327 RNTO SITE SIZE SMNT STAT STOR STOU STRU SYST TYPE USER XCUP XCWD XMKD
328 XPWD XRMD
329 214 Help OK.
331 static void
332 handle_feat(unsigned status)
334 cmdio_write(status, "-Features:");
335 cmdio_write_raw(" EPSV\r\n"
336 " PASV\r\n"
337 " REST STREAM\r\n"
338 " MDTM\r\n"
339 " SIZE\r\n");
340 cmdio_write(status, " Ok");
343 /* Download commands */
345 static inline int
346 port_active(void)
348 return (G.port_addr != NULL);
351 static inline int
352 pasv_active(void)
354 return (G.pasv_listen_fd > STDOUT_FILENO);
357 static void
358 port_pasv_cleanup(void)
360 free(G.port_addr);
361 G.port_addr = NULL;
362 if (G.pasv_listen_fd > STDOUT_FILENO)
363 close(G.pasv_listen_fd);
364 G.pasv_listen_fd = -1;
367 /* On error, emits error code to the peer */
368 static int
369 ftpdataio_get_pasv_fd(void)
371 int remote_fd;
373 remote_fd = accept(G.pasv_listen_fd, NULL, 0);
375 if (remote_fd < 0) {
376 WRITE_ERR(FTP_BADSENDCONN);
377 return remote_fd;
380 setsockopt(remote_fd, SOL_SOCKET, SO_KEEPALIVE, &const_int_1, sizeof(const_int_1));
381 return remote_fd;
384 /* Clears port/pasv data.
385 * This means we dont waste resources, for example, keeping
386 * PASV listening socket open when it is no longer needed.
387 * On error, emits error code to the peer (or exits).
388 * On success, emits p_status_msg to the peer.
390 static int
391 get_remote_transfer_fd(const char *p_status_msg)
393 int remote_fd;
395 if (pasv_active())
396 /* On error, emits error code to the peer */
397 remote_fd = ftpdataio_get_pasv_fd();
398 else
399 /* Exits on error */
400 remote_fd = xconnect_stream(G.port_addr);
402 port_pasv_cleanup();
404 if (remote_fd < 0)
405 return remote_fd;
407 cmdio_write(STRNUM32(FTP_DATACONN), p_status_msg);
408 return remote_fd;
411 /* If there were neither PASV nor PORT, emits error code to the peer */
412 static int
413 port_or_pasv_was_seen(void)
415 if (!pasv_active() && !port_active()) {
416 cmdio_write_raw(STR(FTP_BADSENDCONN)" Use PORT/PASV first\r\n");
417 return 0;
420 return 1;
423 /* Exits on error */
424 static unsigned
425 bind_for_passive_mode(void)
427 int fd;
428 unsigned port;
430 port_pasv_cleanup();
432 G.pasv_listen_fd = fd = xsocket(G.local_addr->u.sa.sa_family, SOCK_STREAM, 0);
433 setsockopt_reuseaddr(fd);
435 set_nport(&G.local_addr->u.sa, 0);
436 xbind(fd, &G.local_addr->u.sa, G.local_addr->len);
437 xlisten(fd, 1);
438 getsockname(fd, &G.local_addr->u.sa, &G.local_addr->len);
440 port = get_nport(&G.local_addr->u.sa);
441 port = ntohs(port);
442 return port;
445 /* Exits on error */
446 static void
447 handle_pasv(void)
449 unsigned port;
450 char *addr, *response;
452 port = bind_for_passive_mode();
454 if (G.local_addr->u.sa.sa_family == AF_INET)
455 addr = xmalloc_sockaddr2dotted_noport(&G.local_addr->u.sa);
456 else /* seen this in the wild done by other ftp servers: */
457 addr = xstrdup("0.0.0.0");
458 replace_char(addr, '.', ',');
460 response = xasprintf(STR(FTP_PASVOK)" PASV ok (%s,%u,%u)\r\n",
461 addr, (int)(port >> 8), (int)(port & 255));
462 free(addr);
463 cmdio_write_raw(response);
464 free(response);
467 /* Exits on error */
468 static void
469 handle_epsv(void)
471 unsigned port;
472 char *response;
474 port = bind_for_passive_mode();
475 response = xasprintf(STR(FTP_EPSVOK)" EPSV ok (|||%u|)\r\n", port);
476 cmdio_write_raw(response);
477 free(response);
480 static void
481 handle_port(void)
483 unsigned port, port_hi;
484 char *raw, *comma;
485 #ifdef WHY_BOTHER_WE_CAN_ASSUME_IP_MATCHES
486 socklen_t peer_ipv4_len;
487 struct sockaddr_in peer_ipv4;
488 struct in_addr port_ipv4_sin_addr;
489 #endif
491 port_pasv_cleanup();
493 raw = G.ftp_arg;
495 /* PORT command format makes sense only over IPv4 */
496 if (!raw
497 #ifdef WHY_BOTHER_WE_CAN_ASSUME_IP_MATCHES
498 || G.local_addr->u.sa.sa_family != AF_INET
499 #endif
501 bail:
502 WRITE_ERR(FTP_BADCMD);
503 return;
506 comma = strrchr(raw, ',');
507 if (comma == NULL)
508 goto bail;
509 *comma = '\0';
510 port = bb_strtou(&comma[1], NULL, 10);
511 if (errno || port > 0xff)
512 goto bail;
514 comma = strrchr(raw, ',');
515 if (comma == NULL)
516 goto bail;
517 *comma = '\0';
518 port_hi = bb_strtou(&comma[1], NULL, 10);
519 if (errno || port_hi > 0xff)
520 goto bail;
521 port |= port_hi << 8;
523 #ifdef WHY_BOTHER_WE_CAN_ASSUME_IP_MATCHES
524 replace_char(raw, ',', '.');
526 /* We are verifying that PORT's IP matches getpeername().
527 * Otherwise peer can make us open data connections
528 * to other hosts (security problem!)
529 * This code would be too simplistic:
530 * lsa = xdotted2sockaddr(raw, port);
531 * if (lsa == NULL) goto bail;
533 if (!inet_aton(raw, &port_ipv4_sin_addr))
534 goto bail;
535 peer_ipv4_len = sizeof(peer_ipv4);
536 if (getpeername(STDIN_FILENO, &peer_ipv4, &peer_ipv4_len) != 0)
537 goto bail;
538 if (memcmp(&port_ipv4_sin_addr, &peer_ipv4.sin_addr, sizeof(struct in_addr)) != 0)
539 goto bail;
541 G.port_addr = xdotted2sockaddr(raw, port);
542 #else
543 G.port_addr = get_peer_lsa(STDIN_FILENO);
544 set_nport(&G.port_addr->u.sa, htons(port));
545 #endif
546 WRITE_OK(FTP_PORTOK);
549 static void
550 handle_rest(void)
552 /* When ftp_arg == NULL simply restart from beginning */
553 G.restart_pos = G.ftp_arg ? xatoi_positive(G.ftp_arg) : 0;
554 WRITE_OK(FTP_RESTOK);
557 static void
558 handle_retr(void)
560 struct stat statbuf;
561 off_t bytes_transferred;
562 int remote_fd;
563 int local_file_fd;
564 off_t offset = G.restart_pos;
565 char *response;
567 G.restart_pos = 0;
569 if (!port_or_pasv_was_seen())
570 return; /* port_or_pasv_was_seen emitted error response */
572 /* O_NONBLOCK is useful if file happens to be a device node */
573 local_file_fd = G.ftp_arg ? open(G.ftp_arg, O_RDONLY | O_NONBLOCK) : -1;
574 if (local_file_fd < 0) {
575 WRITE_ERR(FTP_FILEFAIL);
576 return;
579 if (fstat(local_file_fd, &statbuf) != 0 || !S_ISREG(statbuf.st_mode)) {
580 /* Note - pretend open failed */
581 WRITE_ERR(FTP_FILEFAIL);
582 goto file_close_out;
584 G.local_file_fd = local_file_fd;
586 /* Now deactive O_NONBLOCK, otherwise we have a problem
587 * on DMAPI filesystems such as XFS DMAPI.
589 ndelay_off(local_file_fd);
591 /* Set the download offset (from REST) if any */
592 if (offset != 0)
593 xlseek(local_file_fd, offset, SEEK_SET);
595 response = xasprintf(
596 " Opening BINARY connection for %s (%"OFF_FMT"u bytes)",
597 G.ftp_arg, statbuf.st_size);
598 remote_fd = get_remote_transfer_fd(response);
599 free(response);
600 if (remote_fd < 0)
601 goto file_close_out;
603 bytes_transferred = bb_copyfd_eof(local_file_fd, remote_fd);
604 close(remote_fd);
605 if (bytes_transferred < 0)
606 WRITE_ERR(FTP_BADSENDFILE);
607 else
608 WRITE_OK(FTP_TRANSFEROK);
610 file_close_out:
611 close(local_file_fd);
612 G.local_file_fd = 0;
615 /* List commands */
617 static int
618 popen_ls(const char *opt)
620 const char *argv[5];
621 struct fd_pair outfd;
622 pid_t pid;
624 argv[0] = "ftpd";
625 argv[1] = opt; /* "-l" or "-1" */
626 #if BB_MMU
627 argv[2] = "--";
628 #else
629 /* NOMMU ftpd ls helper chdirs to argv[2],
630 * preventing peer from seeing real root. */
631 argv[2] = xrealloc_getcwd_or_warn(NULL);
632 #endif
633 argv[3] = G.ftp_arg;
634 argv[4] = NULL;
636 /* Improve compatibility with non-RFC conforming FTP clients
637 * which send e.g. "LIST -l", "LIST -la", "LIST -aL".
638 * See https://bugs.kde.org/show_bug.cgi?id=195578 */
639 if (ENABLE_FEATURE_FTPD_ACCEPT_BROKEN_LIST
640 && G.ftp_arg && G.ftp_arg[0] == '-'
642 const char *tmp = strchr(G.ftp_arg, ' ');
643 if (tmp) /* skip the space */
644 tmp++;
645 argv[3] = tmp;
648 xpiped_pair(outfd);
650 /*fflush_all(); - so far we dont use stdio on output */
651 pid = BB_MMU ? xfork() : xvfork();
652 if (pid == 0) {
653 /* child */
654 #if !BB_MMU
655 /* On NOMMU, we want to execute a child - copy of ourself.
656 * In chroot we usually can't do it. Thus we chdir
657 * out of the chroot back to original root,
658 * and (see later below) execute bb_busybox_exec_path
659 * relative to current directory */
660 if (fchdir(G.root_fd) != 0)
661 _exit(127);
662 /*close(G.root_fd); - close_on_exec_on() took care of this */
663 #endif
664 /* NB: close _first_, then move fd! */
665 close(outfd.rd);
666 xmove_fd(outfd.wr, STDOUT_FILENO);
667 /* Opening /dev/null in chroot is hard.
668 * Just making sure STDIN_FILENO is opened
669 * to something harmless. Paranoia,
670 * ls won't read it anyway */
671 close(STDIN_FILENO);
672 dup(STDOUT_FILENO); /* copy will become STDIN_FILENO */
673 #if BB_MMU
674 /* memset(&G, 0, sizeof(G)); - ls_main does it */
675 exit(ls_main(ARRAY_SIZE(argv) - 1, (char**) argv));
676 #else
677 /* + 1: we must use relative path here if in chroot.
678 * For example, execv("/proc/self/exe") will fail, since
679 * it looks for "/proc/self/exe" _relative to chroot!_ */
680 execv(bb_busybox_exec_path + 1, (char**) argv);
681 _exit(127);
682 #endif
685 /* parent */
686 close(outfd.wr);
687 #if !BB_MMU
688 free((char*)argv[2]);
689 #endif
690 return outfd.rd;
693 enum {
694 USE_CTRL_CONN = 1,
695 LONG_LISTING = 2,
698 static void
699 handle_dir_common(int opts)
701 FILE *ls_fp;
702 char *line;
703 int ls_fd;
705 if (!(opts & USE_CTRL_CONN) && !port_or_pasv_was_seen())
706 return; /* port_or_pasv_was_seen emitted error response */
708 /* -n prevents user/groupname display,
709 * which can be problematic in chroot */
710 ls_fd = popen_ls((opts & LONG_LISTING) ? "-l" : "-1");
711 ls_fp = xfdopen_for_read(ls_fd);
713 if (opts & USE_CTRL_CONN) {
714 /* STAT <filename> */
715 cmdio_write_raw(STR(FTP_STATFILE_OK)"-File status:\r\n");
716 while (1) {
717 line = xmalloc_fgetline(ls_fp);
718 if (!line)
719 break;
720 /* Hack: 0 results in no status at all */
721 /* Note: it's ok that we don't prepend space,
722 * ftp.kernel.org doesn't do that too */
723 cmdio_write(0, line);
724 free(line);
726 WRITE_OK(FTP_STATFILE_OK);
727 } else {
728 /* LIST/NLST [<filename>] */
729 int remote_fd = get_remote_transfer_fd(" Directory listing");
730 if (remote_fd >= 0) {
731 while (1) {
732 line = xmalloc_fgetline(ls_fp);
733 if (!line)
734 break;
735 /* I've seen clients complaining when they
736 * are fed with ls output with bare '\n'.
737 * Pity... that would be much simpler.
739 /* TODO: need to s/LF/NUL/g here */
740 xwrite_str(remote_fd, line);
741 xwrite(remote_fd, "\r\n", 2);
742 free(line);
745 close(remote_fd);
746 WRITE_OK(FTP_TRANSFEROK);
748 fclose(ls_fp); /* closes ls_fd too */
750 static void
751 handle_list(void)
753 handle_dir_common(LONG_LISTING);
755 static void
756 handle_nlst(void)
758 /* NLST returns list of names, "\r\n" terminated without regard
759 * to the current binary flag. Names may start with "/",
760 * then they represent full names (we don't produce such names),
761 * otherwise names are relative to current directory.
762 * Embedded "\n" are replaced by NULs. This is safe since names
763 * can never contain NUL.
765 handle_dir_common(0);
767 static void
768 handle_stat_file(void)
770 handle_dir_common(LONG_LISTING + USE_CTRL_CONN);
773 /* This can be extended to handle MLST, as all info is available
774 * in struct stat for that:
775 * MLST file_name
776 * 250-Listing file_name
777 * type=file;size=4161;modify=19970214165800; /dir/dir/file_name
778 * 250 End
779 * Nano-doc:
780 * MLST [<file or dir name, "." assumed if not given>]
781 * Returned name should be either the same as requested, or fully qualified.
782 * If there was no parameter, return "" or (preferred) fully-qualified name.
783 * Returned "facts" (case is not important):
784 * size - size in octets
785 * modify - last modification time
786 * type - entry type (file,dir,OS.unix=block)
787 * (+ cdir and pdir types for MLSD)
788 * unique - unique id of file/directory (inode#)
789 * perm -
790 * a: can be appended to (APPE)
791 * d: can be deleted (RMD/DELE)
792 * f: can be renamed (RNFR)
793 * r: can be read (RETR)
794 * w: can be written (STOR)
795 * e: can CWD into this dir
796 * l: this dir can be listed (dir only!)
797 * c: can create files in this dir
798 * m: can create dirs in this dir (MKD)
799 * p: can delete files in this dir
800 * UNIX.mode - unix file mode
802 static void
803 handle_size_or_mdtm(int need_size)
805 struct stat statbuf;
806 struct tm broken_out;
807 char buf[(sizeof("NNN %"OFF_FMT"u\r\n") + sizeof(off_t) * 3)
808 | sizeof("NNN YYYYMMDDhhmmss\r\n")
811 if (!G.ftp_arg
812 || stat(G.ftp_arg, &statbuf) != 0
813 || !S_ISREG(statbuf.st_mode)
815 WRITE_ERR(FTP_FILEFAIL);
816 return;
818 if (need_size) {
819 sprintf(buf, STR(FTP_STATFILE_OK)" %"OFF_FMT"u\r\n", statbuf.st_size);
820 } else {
821 gmtime_r(&statbuf.st_mtime, &broken_out);
822 sprintf(buf, STR(FTP_STATFILE_OK)" %04u%02u%02u%02u%02u%02u\r\n",
823 broken_out.tm_year + 1900,
824 broken_out.tm_mon + 1,
825 broken_out.tm_mday,
826 broken_out.tm_hour,
827 broken_out.tm_min,
828 broken_out.tm_sec);
830 cmdio_write_raw(buf);
833 /* Upload commands */
835 #if ENABLE_FEATURE_FTP_WRITE
836 static void
837 handle_mkd(void)
839 if (!G.ftp_arg || mkdir(G.ftp_arg, 0777) != 0) {
840 WRITE_ERR(FTP_FILEFAIL);
841 return;
843 WRITE_OK(FTP_MKDIROK);
846 static void
847 handle_rmd(void)
849 if (!G.ftp_arg || rmdir(G.ftp_arg) != 0) {
850 WRITE_ERR(FTP_FILEFAIL);
851 return;
853 WRITE_OK(FTP_RMDIROK);
856 static void
857 handle_dele(void)
859 if (!G.ftp_arg || unlink(G.ftp_arg) != 0) {
860 WRITE_ERR(FTP_FILEFAIL);
861 return;
863 WRITE_OK(FTP_DELEOK);
866 static void
867 handle_rnfr(void)
869 free(G.rnfr_filename);
870 G.rnfr_filename = xstrdup(G.ftp_arg);
871 WRITE_OK(FTP_RNFROK);
874 static void
875 handle_rnto(void)
877 int retval;
879 /* If we didn't get a RNFR, throw a wobbly */
880 if (G.rnfr_filename == NULL || G.ftp_arg == NULL) {
881 cmdio_write_raw(STR(FTP_NEEDRNFR)" Use RNFR first\r\n");
882 return;
885 retval = rename(G.rnfr_filename, G.ftp_arg);
886 free(G.rnfr_filename);
887 G.rnfr_filename = NULL;
889 if (retval) {
890 WRITE_ERR(FTP_FILEFAIL);
891 return;
893 WRITE_OK(FTP_RENAMEOK);
896 static void
897 handle_upload_common(int is_append, int is_unique)
899 struct stat statbuf;
900 char *tempname;
901 off_t bytes_transferred;
902 off_t offset;
903 int local_file_fd;
904 int remote_fd;
906 offset = G.restart_pos;
907 G.restart_pos = 0;
909 if (!port_or_pasv_was_seen())
910 return; /* port_or_pasv_was_seen emitted error response */
912 tempname = NULL;
913 local_file_fd = -1;
914 if (is_unique) {
915 tempname = xstrdup(" FILE: uniq.XXXXXX");
916 local_file_fd = mkstemp(tempname + 7);
917 } else if (G.ftp_arg) {
918 int flags = O_WRONLY | O_CREAT | O_TRUNC;
919 if (is_append)
920 flags = O_WRONLY | O_CREAT | O_APPEND;
921 if (offset)
922 flags = O_WRONLY | O_CREAT;
923 local_file_fd = open(G.ftp_arg, flags, 0666);
926 if (local_file_fd < 0
927 || fstat(local_file_fd, &statbuf) != 0
928 || !S_ISREG(statbuf.st_mode)
930 free(tempname);
931 WRITE_ERR(FTP_UPLOADFAIL);
932 if (local_file_fd >= 0)
933 goto close_local_and_bail;
934 return;
936 G.local_file_fd = local_file_fd;
938 if (offset)
939 xlseek(local_file_fd, offset, SEEK_SET);
941 remote_fd = get_remote_transfer_fd(tempname ? tempname : " Ok to send data");
942 free(tempname);
944 if (remote_fd < 0)
945 goto close_local_and_bail;
947 bytes_transferred = bb_copyfd_eof(remote_fd, local_file_fd);
948 close(remote_fd);
949 if (bytes_transferred < 0)
950 WRITE_ERR(FTP_BADSENDFILE);
951 else
952 WRITE_OK(FTP_TRANSFEROK);
954 close_local_and_bail:
955 close(local_file_fd);
956 G.local_file_fd = 0;
959 static void
960 handle_stor(void)
962 handle_upload_common(0, 0);
965 static void
966 handle_appe(void)
968 G.restart_pos = 0;
969 handle_upload_common(1, 0);
972 static void
973 handle_stou(void)
975 G.restart_pos = 0;
976 handle_upload_common(0, 1);
978 #endif /* ENABLE_FEATURE_FTP_WRITE */
980 static uint32_t
981 cmdio_get_cmd_and_arg(void)
983 int len;
984 uint32_t cmdval;
985 char *cmd;
987 alarm(G.timeout);
989 free(G.ftp_cmd);
991 /* Paranoia. Peer may send 1 gigabyte long cmd... */
992 /* Using separate len_on_stk instead of len optimizes
993 * code size (allows len to be in CPU register) */
994 size_t len_on_stk = 8 * 1024;
995 G.ftp_cmd = cmd = xmalloc_fgets_str_len(stdin, "\r\n", &len_on_stk);
996 if (!cmd)
997 exit(0);
998 len = len_on_stk;
1001 /* De-escape telnet: 0xff,0xff => 0xff */
1002 /* RFC959 says that ABOR, STAT, QUIT may be sent even during
1003 * data transfer, and may be preceded by telnet's "Interrupt Process"
1004 * code (two-byte sequence 255,244) and then by telnet "Synch" code
1005 * 255,242 (byte 242 is sent with TCP URG bit using send(MSG_OOB)
1006 * and may generate SIGURG on our side. See RFC854).
1007 * So far we don't support that (may install SIGURG handler if we'd want to),
1008 * but we need to at least remove 255,xxx pairs. lftp sends those. */
1009 /* Then de-escape FTP: NUL => '\n' */
1010 /* Testing for \xff:
1011 * Create file named '\xff': echo Hello >`echo -ne "\xff"`
1012 * Try to get it: ftpget -v 127.0.0.1 Eff `echo -ne "\xff\xff"`
1013 * (need "\xff\xff" until ftpget applet is fixed to do escaping :)
1014 * Testing for embedded LF:
1015 * LF_HERE=`echo -ne "LF\nHERE"`
1016 * echo Hello >"$LF_HERE"
1017 * ftpget -v 127.0.0.1 LF_HERE "$LF_HERE"
1020 int dst, src;
1022 /* Strip "\r\n" if it is there */
1023 if (len != 0 && cmd[len - 1] == '\n') {
1024 len--;
1025 if (len != 0 && cmd[len - 1] == '\r')
1026 len--;
1027 cmd[len] = '\0';
1029 src = strchrnul(cmd, 0xff) - cmd;
1030 /* 99,99% there are neither NULs nor 255s and src == len */
1031 if (src < len) {
1032 dst = src;
1033 do {
1034 if ((unsigned char)(cmd[src]) == 255) {
1035 src++;
1036 /* 255,xxx - skip 255 */
1037 if ((unsigned char)(cmd[src]) != 255) {
1038 /* 255,!255 - skip both */
1039 src++;
1040 continue;
1042 /* 255,255 - retain one 255 */
1044 /* NUL => '\n' */
1045 cmd[dst++] = cmd[src] ? cmd[src] : '\n';
1046 src++;
1047 } while (src < len);
1048 cmd[dst] = '\0';
1052 if (G.verbose > 1)
1053 verbose_log(cmd);
1055 G.ftp_arg = strchr(cmd, ' ');
1056 if (G.ftp_arg != NULL)
1057 *G.ftp_arg++ = '\0';
1059 /* Uppercase and pack into uint32_t first word of the command */
1060 cmdval = 0;
1061 while (*cmd)
1062 cmdval = (cmdval << 8) + ((unsigned char)*cmd++ & (unsigned char)~0x20);
1064 return cmdval;
1067 #define mk_const4(a,b,c,d) (((a * 0x100 + b) * 0x100 + c) * 0x100 + d)
1068 #define mk_const3(a,b,c) ((a * 0x100 + b) * 0x100 + c)
1069 enum {
1070 const_ALLO = mk_const4('A', 'L', 'L', 'O'),
1071 const_APPE = mk_const4('A', 'P', 'P', 'E'),
1072 const_CDUP = mk_const4('C', 'D', 'U', 'P'),
1073 const_CWD = mk_const3('C', 'W', 'D'),
1074 const_DELE = mk_const4('D', 'E', 'L', 'E'),
1075 const_EPSV = mk_const4('E', 'P', 'S', 'V'),
1076 const_FEAT = mk_const4('F', 'E', 'A', 'T'),
1077 const_HELP = mk_const4('H', 'E', 'L', 'P'),
1078 const_LIST = mk_const4('L', 'I', 'S', 'T'),
1079 const_MDTM = mk_const4('M', 'D', 'T', 'M'),
1080 const_MKD = mk_const3('M', 'K', 'D'),
1081 const_MODE = mk_const4('M', 'O', 'D', 'E'),
1082 const_NLST = mk_const4('N', 'L', 'S', 'T'),
1083 const_NOOP = mk_const4('N', 'O', 'O', 'P'),
1084 const_PASS = mk_const4('P', 'A', 'S', 'S'),
1085 const_PASV = mk_const4('P', 'A', 'S', 'V'),
1086 const_PORT = mk_const4('P', 'O', 'R', 'T'),
1087 const_PWD = mk_const3('P', 'W', 'D'),
1088 const_QUIT = mk_const4('Q', 'U', 'I', 'T'),
1089 const_REST = mk_const4('R', 'E', 'S', 'T'),
1090 const_RETR = mk_const4('R', 'E', 'T', 'R'),
1091 const_RMD = mk_const3('R', 'M', 'D'),
1092 const_RNFR = mk_const4('R', 'N', 'F', 'R'),
1093 const_RNTO = mk_const4('R', 'N', 'T', 'O'),
1094 const_SIZE = mk_const4('S', 'I', 'Z', 'E'),
1095 const_STAT = mk_const4('S', 'T', 'A', 'T'),
1096 const_STOR = mk_const4('S', 'T', 'O', 'R'),
1097 const_STOU = mk_const4('S', 'T', 'O', 'U'),
1098 const_STRU = mk_const4('S', 'T', 'R', 'U'),
1099 const_SYST = mk_const4('S', 'Y', 'S', 'T'),
1100 const_TYPE = mk_const4('T', 'Y', 'P', 'E'),
1101 const_USER = mk_const4('U', 'S', 'E', 'R'),
1103 #if !BB_MMU
1104 OPT_l = (1 << 0),
1105 OPT_1 = (1 << 1),
1106 #endif
1107 OPT_v = (1 << ((!BB_MMU) * 2 + 0)),
1108 OPT_S = (1 << ((!BB_MMU) * 2 + 1)),
1109 OPT_w = (1 << ((!BB_MMU) * 2 + 2)) * ENABLE_FEATURE_FTP_WRITE,
1112 int ftpd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
1113 #if !BB_MMU
1114 int ftpd_main(int argc, char **argv)
1115 #else
1116 int ftpd_main(int argc UNUSED_PARAM, char **argv)
1117 #endif
1119 unsigned abs_timeout;
1120 unsigned verbose_S;
1121 smallint opts;
1123 INIT_G();
1125 abs_timeout = 1 * 60 * 60;
1126 verbose_S = 0;
1127 G.timeout = 2 * 60;
1128 opt_complementary = "t+:T+:vv:SS";
1129 #if BB_MMU
1130 opts = getopt32(argv, "vS" IF_FEATURE_FTP_WRITE("w") "t:T:", &G.timeout, &abs_timeout, &G.verbose, &verbose_S);
1131 #else
1132 opts = getopt32(argv, "l1vS" IF_FEATURE_FTP_WRITE("w") "t:T:", &G.timeout, &abs_timeout, &G.verbose, &verbose_S);
1133 if (opts & (OPT_l|OPT_1)) {
1134 /* Our secret backdoor to ls */
1135 /* TODO: pass -n? It prevents user/group resolution, which may not work in chroot anyway */
1136 /* TODO: pass -A? It shows dot files */
1137 /* TODO: pass --group-directories-first? would be nice, but ls doesn't do that yet */
1138 xchdir(argv[2]);
1139 argv[2] = (char*)"--";
1140 /* memset(&G, 0, sizeof(G)); - ls_main does it */
1141 return ls_main(argc, argv);
1143 #endif
1144 if (G.verbose < verbose_S)
1145 G.verbose = verbose_S;
1146 if (abs_timeout | G.timeout) {
1147 if (abs_timeout == 0)
1148 abs_timeout = INT_MAX;
1149 G.end_time = monotonic_sec() + abs_timeout;
1150 if (G.timeout > abs_timeout)
1151 G.timeout = abs_timeout;
1153 strcpy(G.msg_ok + 4, MSG_OK );
1154 strcpy(G.msg_err + 4, MSG_ERR);
1156 G.local_addr = get_sock_lsa(STDIN_FILENO);
1157 if (!G.local_addr) {
1158 /* This is confusing:
1159 * bb_error_msg_and_die("stdin is not a socket");
1160 * Better: */
1161 bb_show_usage();
1162 /* Help text says that ftpd must be used as inetd service,
1163 * which is by far the most usual cause of get_sock_lsa
1164 * failure */
1167 if (!(opts & OPT_v))
1168 logmode = LOGMODE_NONE;
1169 if (opts & OPT_S) {
1170 /* LOG_NDELAY is needed since we may chroot later */
1171 openlog(applet_name, LOG_PID | LOG_NDELAY, LOG_DAEMON);
1172 logmode |= LOGMODE_SYSLOG;
1174 if (logmode)
1175 applet_name = xasprintf("%s[%u]", applet_name, (int)getpid());
1177 #if !BB_MMU
1178 G.root_fd = xopen("/", O_RDONLY | O_DIRECTORY);
1179 close_on_exec_on(G.root_fd);
1180 #endif
1182 if (argv[optind]) {
1183 xchroot(argv[optind]);
1186 //umask(077); - admin can set umask before starting us
1188 /* Signals. We'll always take -EPIPE rather than a rude signal, thanks */
1189 signal(SIGPIPE, SIG_IGN);
1191 /* Set up options on the command socket (do we need these all? why?) */
1192 setsockopt(STDIN_FILENO, IPPROTO_TCP, TCP_NODELAY, &const_int_1, sizeof(const_int_1));
1193 setsockopt(STDIN_FILENO, SOL_SOCKET, SO_KEEPALIVE, &const_int_1, sizeof(const_int_1));
1194 /* Telnet protocol over command link may send "urgent" data,
1195 * we prefer it to be received in the "normal" data stream: */
1196 setsockopt(STDIN_FILENO, SOL_SOCKET, SO_OOBINLINE, &const_int_1, sizeof(const_int_1));
1198 WRITE_OK(FTP_GREET);
1199 signal(SIGALRM, timeout_handler);
1201 #ifdef IF_WE_WANT_TO_REQUIRE_LOGIN
1203 smallint user_was_specified = 0;
1204 while (1) {
1205 uint32_t cmdval = cmdio_get_cmd_and_arg();
1207 if (cmdval == const_USER) {
1208 if (G.ftp_arg == NULL || strcasecmp(G.ftp_arg, "anonymous") != 0)
1209 cmdio_write_raw(STR(FTP_LOGINERR)" Server is anonymous only\r\n");
1210 else {
1211 user_was_specified = 1;
1212 cmdio_write_raw(STR(FTP_GIVEPWORD)" Please specify the password\r\n");
1214 } else if (cmdval == const_PASS) {
1215 if (user_was_specified)
1216 break;
1217 cmdio_write_raw(STR(FTP_NEEDUSER)" Login with USER\r\n");
1218 } else if (cmdval == const_QUIT) {
1219 WRITE_OK(FTP_GOODBYE);
1220 return 0;
1221 } else {
1222 cmdio_write_raw(STR(FTP_LOGINERR)" Login with USER and PASS\r\n");
1226 WRITE_OK(FTP_LOGINOK);
1227 #endif
1229 /* RFC-959 Section 5.1
1230 * The following commands and options MUST be supported by every
1231 * server-FTP and user-FTP, except in cases where the underlying
1232 * file system or operating system does not allow or support
1233 * a particular command.
1234 * Type: ASCII Non-print, IMAGE, LOCAL 8
1235 * Mode: Stream
1236 * Structure: File, Record*
1237 * (Record structure is REQUIRED only for hosts whose file
1238 * systems support record structure).
1239 * Commands:
1240 * USER, PASS, ACCT, [bbox: ACCT not supported]
1241 * PORT, PASV,
1242 * TYPE, MODE, STRU,
1243 * RETR, STOR, APPE,
1244 * RNFR, RNTO, DELE,
1245 * CWD, CDUP, RMD, MKD, PWD,
1246 * LIST, NLST,
1247 * SYST, STAT,
1248 * HELP, NOOP, QUIT.
1250 /* ACCOUNT (ACCT)
1251 * "The argument field is a Telnet string identifying the user's account.
1252 * The command is not necessarily related to the USER command, as some
1253 * sites may require an account for login and others only for specific
1254 * access, such as storing files. In the latter case the command may
1255 * arrive at any time.
1256 * There are reply codes to differentiate these cases for the automation:
1257 * when account information is required for login, the response to
1258 * a successful PASSword command is reply code 332. On the other hand,
1259 * if account information is NOT required for login, the reply to
1260 * a successful PASSword command is 230; and if the account information
1261 * is needed for a command issued later in the dialogue, the server
1262 * should return a 332 or 532 reply depending on whether it stores
1263 * (pending receipt of the ACCounT command) or discards the command,
1264 * respectively."
1267 while (1) {
1268 uint32_t cmdval = cmdio_get_cmd_and_arg();
1270 if (cmdval == const_QUIT) {
1271 WRITE_OK(FTP_GOODBYE);
1272 return 0;
1274 else if (cmdval == const_USER)
1275 /* This would mean "ok, now give me PASS". */
1276 /*WRITE_OK(FTP_GIVEPWORD);*/
1277 /* vsftpd can be configured to not require that,
1278 * and this also saves one roundtrip:
1280 WRITE_OK(FTP_LOGINOK);
1281 else if (cmdval == const_PASS)
1282 WRITE_OK(FTP_LOGINOK);
1283 else if (cmdval == const_NOOP)
1284 WRITE_OK(FTP_NOOPOK);
1285 else if (cmdval == const_TYPE)
1286 WRITE_OK(FTP_TYPEOK);
1287 else if (cmdval == const_STRU)
1288 WRITE_OK(FTP_STRUOK);
1289 else if (cmdval == const_MODE)
1290 WRITE_OK(FTP_MODEOK);
1291 else if (cmdval == const_ALLO)
1292 WRITE_OK(FTP_ALLOOK);
1293 else if (cmdval == const_SYST)
1294 cmdio_write_raw(STR(FTP_SYSTOK)" UNIX Type: L8\r\n");
1295 else if (cmdval == const_PWD)
1296 handle_pwd();
1297 else if (cmdval == const_CWD)
1298 handle_cwd();
1299 else if (cmdval == const_CDUP) /* cd .. */
1300 handle_cdup();
1301 /* HELP is nearly useless, but we can reuse FEAT for it */
1302 /* lftp uses FEAT */
1303 else if (cmdval == const_HELP || cmdval == const_FEAT)
1304 handle_feat(cmdval == const_HELP
1305 ? STRNUM32(FTP_HELP)
1306 : STRNUM32(FTP_STATOK)
1308 else if (cmdval == const_LIST) /* ls -l */
1309 handle_list();
1310 else if (cmdval == const_NLST) /* "name list", bare ls */
1311 handle_nlst();
1312 /* SIZE is crucial for wget's download indicator etc */
1313 /* Mozilla, lftp use MDTM (presumably for caching) */
1314 else if (cmdval == const_SIZE || cmdval == const_MDTM)
1315 handle_size_or_mdtm(cmdval == const_SIZE);
1316 else if (cmdval == const_STAT) {
1317 if (G.ftp_arg == NULL)
1318 handle_stat();
1319 else
1320 handle_stat_file();
1322 else if (cmdval == const_PASV)
1323 handle_pasv();
1324 else if (cmdval == const_EPSV)
1325 handle_epsv();
1326 else if (cmdval == const_RETR)
1327 handle_retr();
1328 else if (cmdval == const_PORT)
1329 handle_port();
1330 else if (cmdval == const_REST)
1331 handle_rest();
1332 #if ENABLE_FEATURE_FTP_WRITE
1333 else if (opts & OPT_w) {
1334 if (cmdval == const_STOR)
1335 handle_stor();
1336 else if (cmdval == const_MKD)
1337 handle_mkd();
1338 else if (cmdval == const_RMD)
1339 handle_rmd();
1340 else if (cmdval == const_DELE)
1341 handle_dele();
1342 else if (cmdval == const_RNFR) /* "rename from" */
1343 handle_rnfr();
1344 else if (cmdval == const_RNTO) /* "rename to" */
1345 handle_rnto();
1346 else if (cmdval == const_APPE)
1347 handle_appe();
1348 else if (cmdval == const_STOU) /* "store unique" */
1349 handle_stou();
1350 else
1351 goto bad_cmd;
1353 #endif
1354 #if 0
1355 else if (cmdval == const_STOR
1356 || cmdval == const_MKD
1357 || cmdval == const_RMD
1358 || cmdval == const_DELE
1359 || cmdval == const_RNFR
1360 || cmdval == const_RNTO
1361 || cmdval == const_APPE
1362 || cmdval == const_STOU
1364 cmdio_write_raw(STR(FTP_NOPERM)" Permission denied\r\n");
1366 #endif
1367 else {
1368 /* Which unsupported commands were seen in the wild?
1369 * (doesn't necessarily mean "we must support them")
1370 * foo 1.2.3: XXXX - comment
1372 #if ENABLE_FEATURE_FTP_WRITE
1373 bad_cmd:
1374 #endif
1375 cmdio_write_raw(STR(FTP_BADCMD)" Unknown command\r\n");