1 /* vi: set sw=4 ts=4: */
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 tarball for details.
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.
17 #include <netinet/tcp.h>
19 #define FTP_DATACONN 150
20 #define FTP_NOOPOK 200
21 #define FTP_TYPEOK 200
22 #define FTP_PORTOK 200
23 #define FTP_STRUOK 200
24 #define FTP_MODEOK 200
25 #define FTP_ALLOOK 202
26 #define FTP_STATOK 211
27 #define FTP_STATFILE_OK 213
29 #define FTP_SYSTOK 215
31 #define FTP_GOODBYE 221
32 #define FTP_TRANSFEROK 226
33 #define FTP_PASVOK 227
34 /*#define FTP_EPRTOK 228*/
35 #define FTP_EPSVOK 229
36 #define FTP_LOGINOK 230
38 #define FTP_RMDIROK 250
39 #define FTP_DELEOK 250
40 #define FTP_RENAMEOK 250
42 #define FTP_MKDIROK 257
43 #define FTP_GIVEPWORD 331
44 #define FTP_RESTOK 350
45 #define FTP_RNFROK 350
46 #define FTP_TIMEOUT 421
47 #define FTP_BADSENDCONN 425
48 #define FTP_BADSENDNET 426
49 #define FTP_BADSENDFILE 451
50 #define FTP_BADCMD 500
51 #define FTP_COMMANDNOTIMPL 502
52 #define FTP_NEEDUSER 503
53 #define FTP_NEEDRNFR 503
54 #define FTP_BADSTRU 504
55 #define FTP_BADMODE 504
56 #define FTP_LOGINERR 530
57 #define FTP_FILEFAIL 550
58 #define FTP_NOPERM 550
59 #define FTP_UPLOADFAIL 553
62 #define STR(s) STR1(s)
64 /* Convert a constant to 3-digit string, packed into uint32_t */
66 /* Shift for Nth decimal digit */
67 SHIFT2 = 0 * BB_LITTLE_ENDIAN + 24 * BB_BIG_ENDIAN,
68 SHIFT1 = 8 * BB_LITTLE_ENDIAN + 16 * BB_BIG_ENDIAN,
69 SHIFT0 = 16 * BB_LITTLE_ENDIAN + 8 * BB_BIG_ENDIAN,
70 /* And for 4th position (space) */
71 SHIFTsp = 24 * BB_LITTLE_ENDIAN + 0 * BB_BIG_ENDIAN,
73 #define STRNUM32(s) (uint32_t)(0 \
74 | (('0' + ((s) / 1 % 10)) << SHIFT0) \
75 | (('0' + ((s) / 10 % 10)) << SHIFT1) \
76 | (('0' + ((s) / 100 % 10)) << SHIFT2) \
78 #define STRNUM32sp(s) (uint32_t)(0 \
80 | (('0' + ((s) / 1 % 10)) << SHIFT0) \
81 | (('0' + ((s) / 10 % 10)) << SHIFT1) \
82 | (('0' + ((s) / 100 % 10)) << SHIFT2) \
85 #define MSG_OK "Operation successful\r\n"
86 #define MSG_ERR "Error\r\n"
99 len_and_sockaddr *local_addr;
100 len_and_sockaddr *port_addr;
103 #if ENABLE_FEATURE_FTP_WRITE
106 /* We need these aligned to uint32_t */
107 char msg_ok [(sizeof("NNN " MSG_OK ) + 3) & 0xfffc];
108 char msg_err[(sizeof("NNN " MSG_ERR) + 3) & 0xfffc];
110 #define G (*(struct globals*)&bb_common_bufsiz1)
111 #define INIT_G() do { \
112 /* Moved to main */ \
113 /*strcpy(G.msg_ok + 4, MSG_OK );*/ \
114 /*strcpy(G.msg_err + 4, MSG_ERR);*/ \
119 escape_text(const char *prepend, const char *str, unsigned escapee)
121 unsigned retlen, remainlen, chunklen;
125 append = (char)escapee;
128 remainlen = strlen(str);
129 retlen = strlen(prepend);
130 ret = xmalloc(retlen + remainlen * 2 + 1 + 1);
131 strcpy(ret, prepend);
134 found = strchrnul(str, escapee);
135 chunklen = found - str + 1;
137 /* Copy chunk up to and including escapee (or NUL) to ret */
138 memcpy(ret + retlen, str, chunklen);
141 if (*found == '\0') {
142 /* It wasn't escapee, it was NUL! */
143 ret[retlen - 1] = append; /* replace NUL */
144 ret[retlen] = '\0'; /* add NUL */
147 ret[retlen++] = escapee; /* duplicate escapee */
153 /* Returns strlen as a bonus */
155 replace_char(char *str, char from, char to)
167 verbose_log(const char *str)
169 bb_error_msg("%.*s", (int)strcspn(str, "\r\n"), str);
172 /* NB: status_str is char[4] packed into uint32_t */
174 cmdio_write(uint32_t status_str, const char *str)
179 /* FTP uses telnet protocol for command link.
180 * In telnet, 0xff is an escape char, and needs to be escaped: */
181 response = escape_text((char *) &status_str, str, (0xff << 8) + '\r');
183 /* FTP sends embedded LFs as NULs */
184 len = replace_char(response, '\n', '\0');
186 response[len++] = '\n'; /* tack on trailing '\n' */
187 xwrite(STDOUT_FILENO, response, len);
189 verbose_log(response);
194 cmdio_write_ok(unsigned status)
196 *(uint32_t *) G.msg_ok = status;
197 xwrite(STDOUT_FILENO, G.msg_ok, sizeof("NNN " MSG_OK) - 1);
199 verbose_log(G.msg_ok);
201 #define WRITE_OK(a) cmdio_write_ok(STRNUM32sp(a))
203 /* TODO: output strerr(errno) if errno != 0? */
205 cmdio_write_error(unsigned status)
207 *(uint32_t *) G.msg_err = status;
208 xwrite(STDOUT_FILENO, G.msg_err, sizeof("NNN " MSG_ERR) - 1);
210 verbose_log(G.msg_err);
212 #define WRITE_ERR(a) cmdio_write_error(STRNUM32sp(a))
215 cmdio_write_raw(const char *p_text)
217 xwrite_str(STDOUT_FILENO, p_text);
223 timeout_handler(int sig UNUSED_PARAM)
226 int sv_errno = errno;
228 if ((int)(monotonic_sec() - G.end_time) >= 0)
231 if (!G.local_file_fd)
234 pos = xlseek(G.local_file_fd, 0, SEEK_CUR);
235 if (pos == G.local_file_pos)
237 G.local_file_pos = pos;
244 cmdio_write_raw(STR(FTP_TIMEOUT)" Timeout\r\n");
245 /* TODO: do we need to abort (as opposed to usual shutdown) data transfer? */
249 /* Simple commands */
254 char *cwd, *response;
256 cwd = xrealloc_getcwd_or_warn(NULL);
260 /* We have to promote each " to "" */
261 response = escape_text(" \"", cwd, ('"' << 8) + '"');
263 cmdio_write(STRNUM32(FTP_PWDOK), response);
270 if (!G.ftp_arg || chdir(G.ftp_arg) != 0) {
271 WRITE_ERR(FTP_FILEFAIL);
280 G.ftp_arg = (char*)"..";
287 cmdio_write_raw(STR(FTP_STATOK)"-Server status:\r\n"
289 STR(FTP_STATOK)" Ok\r\n");
292 /* Examples of HELP and FEAT:
293 # nc -vvv ftp.kernel.org 21
294 ftp.kernel.org (130.239.17.4:21) open
295 220 Welcome to ftp.kernel.org.
308 214-The following commands are recognized.
309 ABOR ACCT ALLO APPE CDUP CWD DELE EPRT EPSV FEAT HELP LIST MDTM MKD
310 MODE NLST NOOP OPTS PASS PASV PORT PWD QUIT REIN REST RETR RMD RNFR
311 RNTO SITE SIZE SMNT STAT STOR STOU STRU SYST TYPE USER XCUP XCWD XMKD
316 handle_feat(unsigned status)
318 cmdio_write(status, "-Features:");
319 cmdio_write_raw(" EPSV\r\n"
324 cmdio_write(status, " Ok");
327 /* Download commands */
332 return (G.port_addr != NULL);
338 return (G.pasv_listen_fd > STDOUT_FILENO);
342 port_pasv_cleanup(void)
346 if (G.pasv_listen_fd > STDOUT_FILENO)
347 close(G.pasv_listen_fd);
348 G.pasv_listen_fd = -1;
351 /* On error, emits error code to the peer */
353 ftpdataio_get_pasv_fd(void)
357 remote_fd = accept(G.pasv_listen_fd, NULL, 0);
360 WRITE_ERR(FTP_BADSENDCONN);
364 setsockopt(remote_fd, SOL_SOCKET, SO_KEEPALIVE, &const_int_1, sizeof(const_int_1));
368 /* Clears port/pasv data.
369 * This means we dont waste resources, for example, keeping
370 * PASV listening socket open when it is no longer needed.
371 * On error, emits error code to the peer (or exits).
372 * On success, emits p_status_msg to the peer.
375 get_remote_transfer_fd(const char *p_status_msg)
380 /* On error, emits error code to the peer */
381 remote_fd = ftpdataio_get_pasv_fd();
384 remote_fd = xconnect_stream(G.port_addr);
391 cmdio_write(STRNUM32(FTP_DATACONN), p_status_msg);
395 /* If there were neither PASV nor PORT, emits error code to the peer */
397 port_or_pasv_was_seen(void)
399 if (!pasv_active() && !port_active()) {
400 cmdio_write_raw(STR(FTP_BADSENDCONN)" Use PORT/PASV first\r\n");
409 bind_for_passive_mode(void)
416 G.pasv_listen_fd = fd = xsocket(G.local_addr->u.sa.sa_family, SOCK_STREAM, 0);
417 setsockopt_reuseaddr(fd);
419 set_nport(G.local_addr, 0);
420 xbind(fd, &G.local_addr->u.sa, G.local_addr->len);
422 getsockname(fd, &G.local_addr->u.sa, &G.local_addr->len);
424 port = get_nport(&G.local_addr->u.sa);
434 char *addr, *response;
436 port = bind_for_passive_mode();
438 if (G.local_addr->u.sa.sa_family == AF_INET)
439 addr = xmalloc_sockaddr2dotted_noport(&G.local_addr->u.sa);
440 else /* seen this in the wild done by other ftp servers: */
441 addr = xstrdup("0.0.0.0");
442 replace_char(addr, '.', ',');
444 response = xasprintf(STR(FTP_PASVOK)" PASV ok (%s,%u,%u)\r\n",
445 addr, (int)(port >> 8), (int)(port & 255));
447 cmdio_write_raw(response);
458 port = bind_for_passive_mode();
459 response = xasprintf(STR(FTP_EPSVOK)" EPSV ok (|||%u|)\r\n", port);
460 cmdio_write_raw(response);
464 /* libbb candidate */
466 len_and_sockaddr* get_peer_lsa(int fd)
468 len_and_sockaddr *lsa;
471 if (getpeername(fd, NULL, &len) != 0)
473 lsa = xzalloc(LSA_LEN_SIZE + len);
475 getpeername(fd, &lsa->u.sa, &lsa->len);
482 unsigned port, port_hi;
484 #ifdef WHY_BOTHER_WE_CAN_ASSUME_IP_MATCHES
485 socklen_t peer_ipv4_len;
486 struct sockaddr_in peer_ipv4;
487 struct in_addr port_ipv4_sin_addr;
494 /* PORT command format makes sense only over IPv4 */
496 #ifdef WHY_BOTHER_WE_CAN_ASSUME_IP_MATCHES
497 || G.local_addr->u.sa.sa_family != AF_INET
501 WRITE_ERR(FTP_BADCMD);
505 comma = strrchr(raw, ',');
509 port = bb_strtou(&comma[1], NULL, 10);
510 if (errno || port > 0xff)
513 comma = strrchr(raw, ',');
517 port_hi = bb_strtou(&comma[1], NULL, 10);
518 if (errno || port_hi > 0xff)
520 port |= port_hi << 8;
522 #ifdef WHY_BOTHER_WE_CAN_ASSUME_IP_MATCHES
523 replace_char(raw, ',', '.');
525 /* We are verifying that PORT's IP matches getpeername().
526 * Otherwise peer can make us open data connections
527 * to other hosts (security problem!)
528 * This code would be too simplistic:
529 * lsa = xdotted2sockaddr(raw, port);
530 * if (lsa == NULL) goto bail;
532 if (!inet_aton(raw, &port_ipv4_sin_addr))
534 peer_ipv4_len = sizeof(peer_ipv4);
535 if (getpeername(STDIN_FILENO, &peer_ipv4, &peer_ipv4_len) != 0)
537 if (memcmp(&port_ipv4_sin_addr, &peer_ipv4.sin_addr, sizeof(struct in_addr)) != 0)
540 G.port_addr = xdotted2sockaddr(raw, port);
542 G.port_addr = get_peer_lsa(STDIN_FILENO);
543 set_nport(G.port_addr, htons(port));
545 WRITE_OK(FTP_PORTOK);
551 /* When ftp_arg == NULL simply restart from beginning */
552 G.restart_pos = G.ftp_arg ? xatoi_u(G.ftp_arg) : 0;
553 WRITE_OK(FTP_RESTOK);
560 off_t bytes_transferred;
563 off_t offset = G.restart_pos;
568 if (!port_or_pasv_was_seen())
569 return; /* port_or_pasv_was_seen emitted error response */
571 /* O_NONBLOCK is useful if file happens to be a device node */
572 local_file_fd = G.ftp_arg ? open(G.ftp_arg, O_RDONLY | O_NONBLOCK) : -1;
573 if (local_file_fd < 0) {
574 WRITE_ERR(FTP_FILEFAIL);
578 if (fstat(local_file_fd, &statbuf) != 0 || !S_ISREG(statbuf.st_mode)) {
579 /* Note - pretend open failed */
580 WRITE_ERR(FTP_FILEFAIL);
583 G.local_file_fd = local_file_fd;
585 /* Now deactive O_NONBLOCK, otherwise we have a problem
586 * on DMAPI filesystems such as XFS DMAPI.
588 ndelay_off(local_file_fd);
590 /* Set the download offset (from REST) if any */
592 xlseek(local_file_fd, offset, SEEK_SET);
594 response = xasprintf(
595 " Opening BINARY connection for %s (%"OFF_FMT"u bytes)",
596 G.ftp_arg, statbuf.st_size);
597 remote_fd = get_remote_transfer_fd(response);
602 bytes_transferred = bb_copyfd_eof(local_file_fd, remote_fd);
604 if (bytes_transferred < 0)
605 WRITE_ERR(FTP_BADSENDFILE);
607 WRITE_OK(FTP_TRANSFEROK);
610 close(local_file_fd);
617 popen_ls(const char *opt)
620 struct fd_pair outfd;
624 argv[1] = opt; /* "-l" or "-1" */
628 /* NOMMU ftpd ls helper chdirs to argv[2],
629 * preventing peer from seeing real root. */
630 argv[2] = xrealloc_getcwd_or_warn(NULL);
635 /* Improve compatibility with non-RFC conforming FTP clients
636 * which send e.g. "LIST -l", "LIST -la".
637 * See https://bugs.kde.org/show_bug.cgi?id=195578 */
638 if (ENABLE_FEATURE_FTPD_ACCEPT_BROKEN_LIST
639 && G.ftp_arg && G.ftp_arg[0] == '-' && G.ftp_arg[1] == 'l'
641 const char *tmp = strchr(G.ftp_arg, ' ');
642 if (tmp) /* skip the space */
649 /*fflush_all(); - so far we dont use stdio on output */
650 pid = BB_MMU ? fork() : vfork();
652 bb_perror_msg_and_die(BB_MMU ? "fork" : "vfork");
657 /* On NOMMU, we want to execute a child - copy of ourself.
658 * In chroot we usually can't do it. Thus we chdir
659 * out of the chroot back to original root,
660 * and (see later below) execute bb_busybox_exec_path
661 * relative to current directory */
662 if (fchdir(G.root_fd) != 0)
664 /*close(G.root_fd); - close_on_exec_on() took care of this */
666 /* NB: close _first_, then move fd! */
668 xmove_fd(outfd.wr, STDOUT_FILENO);
669 /* Opening /dev/null in chroot is hard.
670 * Just making sure STDIN_FILENO is opened
671 * to something harmless. Paranoia,
672 * ls won't read it anyway */
674 dup(STDOUT_FILENO); /* copy will become STDIN_FILENO */
676 /* memset(&G, 0, sizeof(G)); - ls_main does it */
677 exit(ls_main(ARRAY_SIZE(argv) - 1, (char**) argv));
679 /* + 1: we must use relative path here if in chroot.
680 * For example, execv("/proc/self/exe") will fail, since
681 * it looks for "/proc/self/exe" _relative to chroot!_ */
682 execv(bb_busybox_exec_path + 1, (char**) argv);
690 free((char*)argv[2]);
701 handle_dir_common(int opts)
707 if (!(opts & USE_CTRL_CONN) && !port_or_pasv_was_seen())
708 return; /* port_or_pasv_was_seen emitted error response */
710 /* -n prevents user/groupname display,
711 * which can be problematic in chroot */
712 ls_fd = popen_ls((opts & LONG_LISTING) ? "-l" : "-1");
713 ls_fp = xfdopen_for_read(ls_fd);
715 if (opts & USE_CTRL_CONN) {
716 /* STAT <filename> */
717 cmdio_write_raw(STR(FTP_STATFILE_OK)"-File status:\r\n");
719 line = xmalloc_fgetline(ls_fp);
722 /* Hack: 0 results in no status at all */
723 /* Note: it's ok that we don't prepend space,
724 * ftp.kernel.org doesn't do that too */
725 cmdio_write(0, line);
728 WRITE_OK(FTP_STATFILE_OK);
730 /* LIST/NLST [<filename>] */
731 int remote_fd = get_remote_transfer_fd(" Directory listing");
732 if (remote_fd >= 0) {
734 line = xmalloc_fgetline(ls_fp);
737 /* I've seen clients complaining when they
738 * are fed with ls output with bare '\n'.
739 * Pity... that would be much simpler.
741 /* TODO: need to s/LF/NUL/g here */
742 xwrite_str(remote_fd, line);
743 xwrite(remote_fd, "\r\n", 2);
748 WRITE_OK(FTP_TRANSFEROK);
750 fclose(ls_fp); /* closes ls_fd too */
755 handle_dir_common(LONG_LISTING);
760 /* NLST returns list of names, "\r\n" terminated without regard
761 * to the current binary flag. Names may start with "/",
762 * then they represent full names (we don't produce such names),
763 * otherwise names are relative to current directory.
764 * Embedded "\n" are replaced by NULs. This is safe since names
765 * can never contain NUL.
767 handle_dir_common(0);
770 handle_stat_file(void)
772 handle_dir_common(LONG_LISTING + USE_CTRL_CONN);
775 /* This can be extended to handle MLST, as all info is available
776 * in struct stat for that:
778 * 250-Listing file_name
779 * type=file;size=4161;modify=19970214165800; /dir/dir/file_name
782 * MLST [<file or dir name, "." assumed if not given>]
783 * Returned name should be either the same as requested, or fully qualified.
784 * If there was no parameter, return "" or (preferred) fully-qualified name.
785 * Returned "facts" (case is not important):
786 * size - size in octets
787 * modify - last modification time
788 * type - entry type (file,dir,OS.unix=block)
789 * (+ cdir and pdir types for MLSD)
790 * unique - unique id of file/directory (inode#)
792 * a: can be appended to (APPE)
793 * d: can be deleted (RMD/DELE)
794 * f: can be renamed (RNFR)
795 * r: can be read (RETR)
796 * w: can be written (STOR)
797 * e: can CWD into this dir
798 * l: this dir can be listed (dir only!)
799 * c: can create files in this dir
800 * m: can create dirs in this dir (MKD)
801 * p: can delete files in this dir
802 * UNIX.mode - unix file mode
805 handle_size_or_mdtm(int need_size)
808 struct tm broken_out;
809 char buf[(sizeof("NNN %"OFF_FMT"u\r\n") + sizeof(off_t) * 3)
810 | sizeof("NNN YYYYMMDDhhmmss\r\n")
814 || stat(G.ftp_arg, &statbuf) != 0
815 || !S_ISREG(statbuf.st_mode)
817 WRITE_ERR(FTP_FILEFAIL);
821 sprintf(buf, STR(FTP_STATFILE_OK)" %"OFF_FMT"u\r\n", statbuf.st_size);
823 gmtime_r(&statbuf.st_mtime, &broken_out);
824 sprintf(buf, STR(FTP_STATFILE_OK)" %04u%02u%02u%02u%02u%02u\r\n",
825 broken_out.tm_year + 1900,
832 cmdio_write_raw(buf);
835 /* Upload commands */
837 #if ENABLE_FEATURE_FTP_WRITE
841 if (!G.ftp_arg || mkdir(G.ftp_arg, 0777) != 0) {
842 WRITE_ERR(FTP_FILEFAIL);
845 WRITE_OK(FTP_MKDIROK);
851 if (!G.ftp_arg || rmdir(G.ftp_arg) != 0) {
852 WRITE_ERR(FTP_FILEFAIL);
855 WRITE_OK(FTP_RMDIROK);
861 if (!G.ftp_arg || unlink(G.ftp_arg) != 0) {
862 WRITE_ERR(FTP_FILEFAIL);
865 WRITE_OK(FTP_DELEOK);
871 free(G.rnfr_filename);
872 G.rnfr_filename = xstrdup(G.ftp_arg);
873 WRITE_OK(FTP_RNFROK);
881 /* If we didn't get a RNFR, throw a wobbly */
882 if (G.rnfr_filename == NULL || G.ftp_arg == NULL) {
883 cmdio_write_raw(STR(FTP_NEEDRNFR)" Use RNFR first\r\n");
887 retval = rename(G.rnfr_filename, G.ftp_arg);
888 free(G.rnfr_filename);
889 G.rnfr_filename = NULL;
892 WRITE_ERR(FTP_FILEFAIL);
895 WRITE_OK(FTP_RENAMEOK);
899 handle_upload_common(int is_append, int is_unique)
903 off_t bytes_transferred;
908 offset = G.restart_pos;
911 if (!port_or_pasv_was_seen())
912 return; /* port_or_pasv_was_seen emitted error response */
917 tempname = xstrdup(" FILE: uniq.XXXXXX");
918 local_file_fd = mkstemp(tempname + 7);
919 } else if (G.ftp_arg) {
920 int flags = O_WRONLY | O_CREAT | O_TRUNC;
922 flags = O_WRONLY | O_CREAT | O_APPEND;
924 flags = O_WRONLY | O_CREAT;
925 local_file_fd = open(G.ftp_arg, flags, 0666);
928 if (local_file_fd < 0
929 || fstat(local_file_fd, &statbuf) != 0
930 || !S_ISREG(statbuf.st_mode)
932 WRITE_ERR(FTP_UPLOADFAIL);
933 if (local_file_fd >= 0)
934 goto close_local_and_bail;
937 G.local_file_fd = local_file_fd;
940 xlseek(local_file_fd, offset, SEEK_SET);
942 remote_fd = get_remote_transfer_fd(tempname ? tempname : " Ok to send data");
946 goto close_local_and_bail;
948 bytes_transferred = bb_copyfd_eof(remote_fd, local_file_fd);
950 if (bytes_transferred < 0)
951 WRITE_ERR(FTP_BADSENDFILE);
953 WRITE_OK(FTP_TRANSFEROK);
955 close_local_and_bail:
956 close(local_file_fd);
963 handle_upload_common(0, 0);
970 handle_upload_common(1, 0);
977 handle_upload_common(0, 1);
979 #endif /* ENABLE_FEATURE_FTP_WRITE */
982 cmdio_get_cmd_and_arg(void)
992 /* Paranoia. Peer may send 1 gigabyte long cmd... */
993 /* Using separate len_on_stk instead of len optimizes
994 * code size (allows len to be in CPU register) */
995 size_t len_on_stk = 8 * 1024;
996 G.ftp_cmd = cmd = xmalloc_fgets_str_len(stdin, "\r\n", &len_on_stk);
1002 /* De-escape telnet: 0xff,0xff => 0xff */
1003 /* RFC959 says that ABOR, STAT, QUIT may be sent even during
1004 * data transfer, and may be preceded by telnet's "Interrupt Process"
1005 * code (two-byte sequence 255,244) and then by telnet "Synch" code
1006 * 255,242 (byte 242 is sent with TCP URG bit using send(MSG_OOB)
1007 * and may generate SIGURG on our side. See RFC854).
1008 * So far we don't support that (may install SIGURG handler if we'd want to),
1009 * but we need to at least remove 255,xxx pairs. lftp sends those. */
1010 /* Then de-escape FTP: NUL => '\n' */
1011 /* Testing for \xff:
1012 * Create file named '\xff': echo Hello >`echo -ne "\xff"`
1013 * Try to get it: ftpget -v 127.0.0.1 Eff `echo -ne "\xff\xff"`
1014 * (need "\xff\xff" until ftpget applet is fixed to do escaping :)
1015 * Testing for embedded LF:
1016 * LF_HERE=`echo -ne "LF\nHERE"`
1017 * echo Hello >"$LF_HERE"
1018 * ftpget -v 127.0.0.1 LF_HERE "$LF_HERE"
1023 /* Strip "\r\n" if it is there */
1024 if (len != 0 && cmd[len - 1] == '\n') {
1026 if (len != 0 && cmd[len - 1] == '\r')
1030 src = strchrnul(cmd, 0xff) - cmd;
1031 /* 99,99% there are neither NULs nor 255s and src == len */
1035 if ((unsigned char)(cmd[src]) == 255) {
1037 /* 255,xxx - skip 255 */
1038 if ((unsigned char)(cmd[src]) != 255) {
1039 /* 255,!255 - skip both */
1043 /* 255,255 - retain one 255 */
1046 cmd[dst++] = cmd[src] ? cmd[src] : '\n';
1048 } while (src < len);
1056 G.ftp_arg = strchr(cmd, ' ');
1057 if (G.ftp_arg != NULL)
1058 *G.ftp_arg++ = '\0';
1060 /* Uppercase and pack into uint32_t first word of the command */
1063 cmdval = (cmdval << 8) + ((unsigned char)*cmd++ & (unsigned char)~0x20);
1068 #define mk_const4(a,b,c,d) (((a * 0x100 + b) * 0x100 + c) * 0x100 + d)
1069 #define mk_const3(a,b,c) ((a * 0x100 + b) * 0x100 + c)
1071 const_ALLO = mk_const4('A', 'L', 'L', 'O'),
1072 const_APPE = mk_const4('A', 'P', 'P', 'E'),
1073 const_CDUP = mk_const4('C', 'D', 'U', 'P'),
1074 const_CWD = mk_const3('C', 'W', 'D'),
1075 const_DELE = mk_const4('D', 'E', 'L', 'E'),
1076 const_EPSV = mk_const4('E', 'P', 'S', 'V'),
1077 const_FEAT = mk_const4('F', 'E', 'A', 'T'),
1078 const_HELP = mk_const4('H', 'E', 'L', 'P'),
1079 const_LIST = mk_const4('L', 'I', 'S', 'T'),
1080 const_MDTM = mk_const4('M', 'D', 'T', 'M'),
1081 const_MKD = mk_const3('M', 'K', 'D'),
1082 const_MODE = mk_const4('M', 'O', 'D', 'E'),
1083 const_NLST = mk_const4('N', 'L', 'S', 'T'),
1084 const_NOOP = mk_const4('N', 'O', 'O', 'P'),
1085 const_PASS = mk_const4('P', 'A', 'S', 'S'),
1086 const_PASV = mk_const4('P', 'A', 'S', 'V'),
1087 const_PORT = mk_const4('P', 'O', 'R', 'T'),
1088 const_PWD = mk_const3('P', 'W', 'D'),
1089 const_QUIT = mk_const4('Q', 'U', 'I', 'T'),
1090 const_REST = mk_const4('R', 'E', 'S', 'T'),
1091 const_RETR = mk_const4('R', 'E', 'T', 'R'),
1092 const_RMD = mk_const3('R', 'M', 'D'),
1093 const_RNFR = mk_const4('R', 'N', 'F', 'R'),
1094 const_RNTO = mk_const4('R', 'N', 'T', 'O'),
1095 const_SIZE = mk_const4('S', 'I', 'Z', 'E'),
1096 const_STAT = mk_const4('S', 'T', 'A', 'T'),
1097 const_STOR = mk_const4('S', 'T', 'O', 'R'),
1098 const_STOU = mk_const4('S', 'T', 'O', 'U'),
1099 const_STRU = mk_const4('S', 'T', 'R', 'U'),
1100 const_SYST = mk_const4('S', 'Y', 'S', 'T'),
1101 const_TYPE = mk_const4('T', 'Y', 'P', 'E'),
1102 const_USER = mk_const4('U', 'S', 'E', 'R'),
1108 OPT_v = (1 << ((!BB_MMU) * 2 + 0)),
1109 OPT_S = (1 << ((!BB_MMU) * 2 + 1)),
1110 OPT_w = (1 << ((!BB_MMU) * 2 + 2)) * ENABLE_FEATURE_FTP_WRITE,
1113 int ftpd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
1115 int ftpd_main(int argc, char **argv)
1117 int ftpd_main(int argc UNUSED_PARAM, char **argv)
1120 unsigned abs_timeout;
1126 abs_timeout = 1 * 60 * 60;
1129 opt_complementary = "t+:T+:vv:SS";
1131 opts = getopt32(argv, "vS" IF_FEATURE_FTP_WRITE("w") "t:T:", &G.timeout, &abs_timeout, &G.verbose, &verbose_S);
1133 opts = getopt32(argv, "l1vS" IF_FEATURE_FTP_WRITE("w") "t:T:", &G.timeout, &abs_timeout, &G.verbose, &verbose_S);
1134 if (opts & (OPT_l|OPT_1)) {
1135 /* Our secret backdoor to ls */
1136 /* TODO: pass -n? It prevents user/group resolution, which may not work in chroot anyway */
1137 /* TODO: pass -A? It shows dot files */
1138 /* TODO: pass --group-directories-first? would be nice, but ls doesn't do that yet */
1140 argv[2] = (char*)"--";
1141 /* memset(&G, 0, sizeof(G)); - ls_main does it */
1142 return ls_main(argc, argv);
1145 if (G.verbose < verbose_S)
1146 G.verbose = verbose_S;
1147 if (abs_timeout | G.timeout) {
1148 if (abs_timeout == 0)
1149 abs_timeout = INT_MAX;
1150 G.end_time = monotonic_sec() + abs_timeout;
1151 if (G.timeout > abs_timeout)
1152 G.timeout = abs_timeout;
1154 strcpy(G.msg_ok + 4, MSG_OK );
1155 strcpy(G.msg_err + 4, MSG_ERR);
1157 G.local_addr = get_sock_lsa(STDIN_FILENO);
1158 if (!G.local_addr) {
1159 /* This is confusing:
1160 * bb_error_msg_and_die("stdin is not a socket");
1163 /* Help text says that ftpd must be used as inetd service,
1164 * which is by far the most usual cause of get_sock_lsa
1168 if (!(opts & OPT_v))
1169 logmode = LOGMODE_NONE;
1171 /* LOG_NDELAY is needed since we may chroot later */
1172 openlog(applet_name, LOG_PID | LOG_NDELAY, LOG_DAEMON);
1173 logmode |= LOGMODE_SYSLOG;
1176 applet_name = xasprintf("%s[%u]", applet_name, (int)getpid());
1179 G.root_fd = xopen("/", O_RDONLY | O_DIRECTORY);
1180 close_on_exec_on(G.root_fd);
1184 xchdir(argv[optind]);
1188 //umask(077); - admin can set umask before starting us
1190 /* Signals. We'll always take -EPIPE rather than a rude signal, thanks */
1191 signal(SIGPIPE, SIG_IGN);
1193 /* Set up options on the command socket (do we need these all? why?) */
1194 setsockopt(STDIN_FILENO, IPPROTO_TCP, TCP_NODELAY, &const_int_1, sizeof(const_int_1));
1195 setsockopt(STDIN_FILENO, SOL_SOCKET, SO_KEEPALIVE, &const_int_1, sizeof(const_int_1));
1196 /* Telnet protocol over command link may send "urgent" data,
1197 * we prefer it to be received in the "normal" data stream: */
1198 setsockopt(STDIN_FILENO, SOL_SOCKET, SO_OOBINLINE, &const_int_1, sizeof(const_int_1));
1200 WRITE_OK(FTP_GREET);
1201 signal(SIGALRM, timeout_handler);
1203 #ifdef IF_WE_WANT_TO_REQUIRE_LOGIN
1205 smallint user_was_specified = 0;
1207 uint32_t cmdval = cmdio_get_cmd_and_arg();
1209 if (cmdval == const_USER) {
1210 if (G.ftp_arg == NULL || strcasecmp(G.ftp_arg, "anonymous") != 0)
1211 cmdio_write_raw(STR(FTP_LOGINERR)" Server is anonymous only\r\n");
1213 user_was_specified = 1;
1214 cmdio_write_raw(STR(FTP_GIVEPWORD)" Please specify the password\r\n");
1216 } else if (cmdval == const_PASS) {
1217 if (user_was_specified)
1219 cmdio_write_raw(STR(FTP_NEEDUSER)" Login with USER\r\n");
1220 } else if (cmdval == const_QUIT) {
1221 WRITE_OK(FTP_GOODBYE);
1224 cmdio_write_raw(STR(FTP_LOGINERR)" Login with USER and PASS\r\n");
1228 WRITE_OK(FTP_LOGINOK);
1231 /* RFC-959 Section 5.1
1232 * The following commands and options MUST be supported by every
1233 * server-FTP and user-FTP, except in cases where the underlying
1234 * file system or operating system does not allow or support
1235 * a particular command.
1236 * Type: ASCII Non-print, IMAGE, LOCAL 8
1238 * Structure: File, Record*
1239 * (Record structure is REQUIRED only for hosts whose file
1240 * systems support record structure).
1242 * USER, PASS, ACCT, [bbox: ACCT not supported]
1247 * CWD, CDUP, RMD, MKD, PWD,
1253 * "The argument field is a Telnet string identifying the user's account.
1254 * The command is not necessarily related to the USER command, as some
1255 * sites may require an account for login and others only for specific
1256 * access, such as storing files. In the latter case the command may
1257 * arrive at any time.
1258 * There are reply codes to differentiate these cases for the automation:
1259 * when account information is required for login, the response to
1260 * a successful PASSword command is reply code 332. On the other hand,
1261 * if account information is NOT required for login, the reply to
1262 * a successful PASSword command is 230; and if the account information
1263 * is needed for a command issued later in the dialogue, the server
1264 * should return a 332 or 532 reply depending on whether it stores
1265 * (pending receipt of the ACCounT command) or discards the command,
1270 uint32_t cmdval = cmdio_get_cmd_and_arg();
1272 if (cmdval == const_QUIT) {
1273 WRITE_OK(FTP_GOODBYE);
1276 else if (cmdval == const_USER)
1277 /* This would mean "ok, now give me PASS". */
1278 /*WRITE_OK(FTP_GIVEPWORD);*/
1279 /* vsftpd can be configured to not require that,
1280 * and this also saves one roundtrip:
1282 WRITE_OK(FTP_LOGINOK);
1283 else if (cmdval == const_PASS)
1284 WRITE_OK(FTP_LOGINOK);
1285 else if (cmdval == const_NOOP)
1286 WRITE_OK(FTP_NOOPOK);
1287 else if (cmdval == const_TYPE)
1288 WRITE_OK(FTP_TYPEOK);
1289 else if (cmdval == const_STRU)
1290 WRITE_OK(FTP_STRUOK);
1291 else if (cmdval == const_MODE)
1292 WRITE_OK(FTP_MODEOK);
1293 else if (cmdval == const_ALLO)
1294 WRITE_OK(FTP_ALLOOK);
1295 else if (cmdval == const_SYST)
1296 cmdio_write_raw(STR(FTP_SYSTOK)" UNIX Type: L8\r\n");
1297 else if (cmdval == const_PWD)
1299 else if (cmdval == const_CWD)
1301 else if (cmdval == const_CDUP) /* cd .. */
1303 /* HELP is nearly useless, but we can reuse FEAT for it */
1304 /* lftp uses FEAT */
1305 else if (cmdval == const_HELP || cmdval == const_FEAT)
1306 handle_feat(cmdval == const_HELP
1307 ? STRNUM32(FTP_HELP)
1308 : STRNUM32(FTP_STATOK)
1310 else if (cmdval == const_LIST) /* ls -l */
1312 else if (cmdval == const_NLST) /* "name list", bare ls */
1314 /* SIZE is crucial for wget's download indicator etc */
1315 /* Mozilla, lftp use MDTM (presumably for caching) */
1316 else if (cmdval == const_SIZE || cmdval == const_MDTM)
1317 handle_size_or_mdtm(cmdval == const_SIZE);
1318 else if (cmdval == const_STAT) {
1319 if (G.ftp_arg == NULL)
1324 else if (cmdval == const_PASV)
1326 else if (cmdval == const_EPSV)
1328 else if (cmdval == const_RETR)
1330 else if (cmdval == const_PORT)
1332 else if (cmdval == const_REST)
1334 #if ENABLE_FEATURE_FTP_WRITE
1335 else if (opts & OPT_w) {
1336 if (cmdval == const_STOR)
1338 else if (cmdval == const_MKD)
1340 else if (cmdval == const_RMD)
1342 else if (cmdval == const_DELE)
1344 else if (cmdval == const_RNFR) /* "rename from" */
1346 else if (cmdval == const_RNTO) /* "rename to" */
1348 else if (cmdval == const_APPE)
1350 else if (cmdval == const_STOU) /* "store unique" */
1357 else if (cmdval == const_STOR
1358 || cmdval == const_MKD
1359 || cmdval == const_RMD
1360 || cmdval == const_DELE
1361 || cmdval == const_RNFR
1362 || cmdval == const_RNTO
1363 || cmdval == const_APPE
1364 || cmdval == const_STOU
1366 cmdio_write_raw(STR(FTP_NOPERM)" Permission denied\r\n");
1370 /* Which unsupported commands were seen in the wild?
1371 * (doesn't necessarily mean "we must support them")
1372 * foo 1.2.3: XXXX - comment
1374 #if ENABLE_FEATURE_FTP_WRITE
1377 cmdio_write_raw(STR(FTP_BADCMD)" Unknown command\r\n");