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 const char *argv[] = {
623 BB_MMU ? "--" : NULL,
627 struct fd_pair outfd;
630 cwd = xrealloc_getcwd_or_warn(NULL);
633 /*fflush_all(); - so far we dont use stdio on output */
634 pid = BB_MMU ? fork() : vfork();
636 bb_perror_msg_and_die(BB_MMU ? "fork" : "vfork");
641 if (fchdir(G.root_fd) != 0)
645 /* NB: close _first_, then move fd! */
647 xmove_fd(outfd.wr, STDOUT_FILENO);
648 /* Opening /dev/null in chroot is hard.
649 * Just making sure STDIN_FILENO is opened
650 * to something harmless. Paranoia,
651 * ls won't read it anyway */
653 dup(STDOUT_FILENO); /* copy will become STDIN_FILENO */
655 /* ftpd ls helper chdirs to argv[2],
656 * preventing peer from seeing real root we are in now
659 /* + 1: we must use relative path here if in chroot.
660 * For example, execv("/proc/self/exe") will fail, since
661 * it looks for "/proc/self/exe" _relative to chroot!_ */
662 execv(bb_busybox_exec_path + 1, (char**) argv);
665 /* memset(&G, 0, sizeof(G)); - ls_main does it */
666 exit(ls_main(ARRAY_SIZE(argv) - 1, (char**) argv));
682 handle_dir_common(int opts)
688 if (!(opts & USE_CTRL_CONN) && !port_or_pasv_was_seen())
689 return; /* port_or_pasv_was_seen emitted error response */
691 /* -n prevents user/groupname display,
692 * which can be problematic in chroot */
693 ls_fd = popen_ls((opts & LONG_LISTING) ? "-l" : "-1");
694 ls_fp = xfdopen_for_read(ls_fd);
696 if (opts & USE_CTRL_CONN) {
697 /* STAT <filename> */
698 cmdio_write_raw(STR(FTP_STATFILE_OK)"-File status:\r\n");
700 line = xmalloc_fgetline(ls_fp);
703 /* Hack: 0 results in no status at all */
704 /* Note: it's ok that we don't prepend space,
705 * ftp.kernel.org doesn't do that too */
706 cmdio_write(0, line);
709 WRITE_OK(FTP_STATFILE_OK);
711 /* LIST/NLST [<filename>] */
712 int remote_fd = get_remote_transfer_fd(" Directory listing");
713 if (remote_fd >= 0) {
715 line = xmalloc_fgetline(ls_fp);
718 /* I've seen clients complaining when they
719 * are fed with ls output with bare '\n'.
720 * Pity... that would be much simpler.
722 /* TODO: need to s/LF/NUL/g here */
723 xwrite_str(remote_fd, line);
724 xwrite(remote_fd, "\r\n", 2);
729 WRITE_OK(FTP_TRANSFEROK);
731 fclose(ls_fp); /* closes ls_fd too */
736 handle_dir_common(LONG_LISTING);
741 /* NLST returns list of names, "\r\n" terminated without regard
742 * to the current binary flag. Names may start with "/",
743 * then they represent full names (we don't produce such names),
744 * otherwise names are relative to current directory.
745 * Embedded "\n" are replaced by NULs. This is safe since names
746 * can never contain NUL.
748 handle_dir_common(0);
751 handle_stat_file(void)
753 handle_dir_common(LONG_LISTING + USE_CTRL_CONN);
756 /* This can be extended to handle MLST, as all info is available
757 * in struct stat for that:
759 * 250-Listing file_name
760 * type=file;size=4161;modify=19970214165800; /dir/dir/file_name
763 * MLST [<file or dir name, "." assumed if not given>]
764 * Returned name should be either the same as requested, or fully qualified.
765 * If there was no parameter, return "" or (preferred) fully-qualified name.
766 * Returned "facts" (case is not important):
767 * size - size in octets
768 * modify - last modification time
769 * type - entry type (file,dir,OS.unix=block)
770 * (+ cdir and pdir types for MLSD)
771 * unique - unique id of file/directory (inode#)
773 * a: can be appended to (APPE)
774 * d: can be deleted (RMD/DELE)
775 * f: can be renamed (RNFR)
776 * r: can be read (RETR)
777 * w: can be written (STOR)
778 * e: can CWD into this dir
779 * l: this dir can be listed (dir only!)
780 * c: can create files in this dir
781 * m: can create dirs in this dir (MKD)
782 * p: can delete files in this dir
783 * UNIX.mode - unix file mode
786 handle_size_or_mdtm(int need_size)
789 struct tm broken_out;
790 char buf[(sizeof("NNN %"OFF_FMT"u\r\n") + sizeof(off_t) * 3)
791 | sizeof("NNN YYYYMMDDhhmmss\r\n")
795 || stat(G.ftp_arg, &statbuf) != 0
796 || !S_ISREG(statbuf.st_mode)
798 WRITE_ERR(FTP_FILEFAIL);
802 sprintf(buf, STR(FTP_STATFILE_OK)" %"OFF_FMT"u\r\n", statbuf.st_size);
804 gmtime_r(&statbuf.st_mtime, &broken_out);
805 sprintf(buf, STR(FTP_STATFILE_OK)" %04u%02u%02u%02u%02u%02u\r\n",
806 broken_out.tm_year + 1900,
813 cmdio_write_raw(buf);
816 /* Upload commands */
818 #if ENABLE_FEATURE_FTP_WRITE
822 if (!G.ftp_arg || mkdir(G.ftp_arg, 0777) != 0) {
823 WRITE_ERR(FTP_FILEFAIL);
826 WRITE_OK(FTP_MKDIROK);
832 if (!G.ftp_arg || rmdir(G.ftp_arg) != 0) {
833 WRITE_ERR(FTP_FILEFAIL);
836 WRITE_OK(FTP_RMDIROK);
842 if (!G.ftp_arg || unlink(G.ftp_arg) != 0) {
843 WRITE_ERR(FTP_FILEFAIL);
846 WRITE_OK(FTP_DELEOK);
852 free(G.rnfr_filename);
853 G.rnfr_filename = xstrdup(G.ftp_arg);
854 WRITE_OK(FTP_RNFROK);
862 /* If we didn't get a RNFR, throw a wobbly */
863 if (G.rnfr_filename == NULL || G.ftp_arg == NULL) {
864 cmdio_write_raw(STR(FTP_NEEDRNFR)" Use RNFR first\r\n");
868 retval = rename(G.rnfr_filename, G.ftp_arg);
869 free(G.rnfr_filename);
870 G.rnfr_filename = NULL;
873 WRITE_ERR(FTP_FILEFAIL);
876 WRITE_OK(FTP_RENAMEOK);
880 handle_upload_common(int is_append, int is_unique)
884 off_t bytes_transferred;
889 offset = G.restart_pos;
892 if (!port_or_pasv_was_seen())
893 return; /* port_or_pasv_was_seen emitted error response */
898 tempname = xstrdup(" FILE: uniq.XXXXXX");
899 local_file_fd = mkstemp(tempname + 7);
900 } else if (G.ftp_arg) {
901 int flags = O_WRONLY | O_CREAT | O_TRUNC;
903 flags = O_WRONLY | O_CREAT | O_APPEND;
905 flags = O_WRONLY | O_CREAT;
906 local_file_fd = open(G.ftp_arg, flags, 0666);
909 if (local_file_fd < 0
910 || fstat(local_file_fd, &statbuf) != 0
911 || !S_ISREG(statbuf.st_mode)
913 WRITE_ERR(FTP_UPLOADFAIL);
914 if (local_file_fd >= 0)
915 goto close_local_and_bail;
918 G.local_file_fd = local_file_fd;
921 xlseek(local_file_fd, offset, SEEK_SET);
923 remote_fd = get_remote_transfer_fd(tempname ? tempname : " Ok to send data");
927 goto close_local_and_bail;
929 bytes_transferred = bb_copyfd_eof(remote_fd, local_file_fd);
931 if (bytes_transferred < 0)
932 WRITE_ERR(FTP_BADSENDFILE);
934 WRITE_OK(FTP_TRANSFEROK);
936 close_local_and_bail:
937 close(local_file_fd);
944 handle_upload_common(0, 0);
951 handle_upload_common(1, 0);
958 handle_upload_common(0, 1);
960 #endif /* ENABLE_FEATURE_FTP_WRITE */
963 cmdio_get_cmd_and_arg(void)
972 len = 8 * 1024; /* Paranoia. Peer may send 1 gigabyte long cmd... */
973 G.ftp_cmd = cmd = xmalloc_fgets_str_len(stdin, "\r\n", &len);
977 /* De-escape telnet: 0xff,0xff => 0xff */
978 /* RFC959 says that ABOR, STAT, QUIT may be sent even during
979 * data transfer, and may be preceded by telnet's "Interrupt Process"
980 * code (two-byte sequence 255,244) and then by telnet "Synch" code
981 * 255,242 (byte 242 is sent with TCP URG bit using send(MSG_OOB)
982 * and may generate SIGURG on our side. See RFC854).
983 * So far we don't support that (may install SIGURG handler if we'd want to),
984 * but we need to at least remove 255,xxx pairs. lftp sends those. */
985 /* Then de-escape FTP: NUL => '\n' */
987 * Create file named '\xff': echo Hello >`echo -ne "\xff"`
988 * Try to get it: ftpget -v 127.0.0.1 Eff `echo -ne "\xff\xff"`
989 * (need "\xff\xff" until ftpget applet is fixed to do escaping :)
990 * Testing for embedded LF:
991 * LF_HERE=`echo -ne "LF\nHERE"`
992 * echo Hello >"$LF_HERE"
993 * ftpget -v 127.0.0.1 LF_HERE "$LF_HERE"
998 /* Strip "\r\n" if it is there */
999 if (len != 0 && cmd[len - 1] == '\n') {
1001 if (len != 0 && cmd[len - 1] == '\r')
1005 src = strchrnul(cmd, 0xff) - cmd;
1006 /* 99,99% there are neither NULs nor 255s and src == len */
1010 if ((unsigned char)(cmd[src]) == 255) {
1012 /* 255,xxx - skip 255 */
1013 if ((unsigned char)(cmd[src]) != 255) {
1014 /* 255,!255 - skip both */
1018 /* 255,255 - retain one 255 */
1021 cmd[dst++] = cmd[src] ? cmd[src] : '\n';
1023 } while (src < len);
1031 G.ftp_arg = strchr(cmd, ' ');
1032 if (G.ftp_arg != NULL)
1033 *G.ftp_arg++ = '\0';
1035 /* Uppercase and pack into uint32_t first word of the command */
1038 cmdval = (cmdval << 8) + ((unsigned char)*cmd++ & (unsigned char)~0x20);
1043 #define mk_const4(a,b,c,d) (((a * 0x100 + b) * 0x100 + c) * 0x100 + d)
1044 #define mk_const3(a,b,c) ((a * 0x100 + b) * 0x100 + c)
1046 const_ALLO = mk_const4('A', 'L', 'L', 'O'),
1047 const_APPE = mk_const4('A', 'P', 'P', 'E'),
1048 const_CDUP = mk_const4('C', 'D', 'U', 'P'),
1049 const_CWD = mk_const3('C', 'W', 'D'),
1050 const_DELE = mk_const4('D', 'E', 'L', 'E'),
1051 const_EPSV = mk_const4('E', 'P', 'S', 'V'),
1052 const_FEAT = mk_const4('F', 'E', 'A', 'T'),
1053 const_HELP = mk_const4('H', 'E', 'L', 'P'),
1054 const_LIST = mk_const4('L', 'I', 'S', 'T'),
1055 const_MDTM = mk_const4('M', 'D', 'T', 'M'),
1056 const_MKD = mk_const3('M', 'K', 'D'),
1057 const_MODE = mk_const4('M', 'O', 'D', 'E'),
1058 const_NLST = mk_const4('N', 'L', 'S', 'T'),
1059 const_NOOP = mk_const4('N', 'O', 'O', 'P'),
1060 const_PASS = mk_const4('P', 'A', 'S', 'S'),
1061 const_PASV = mk_const4('P', 'A', 'S', 'V'),
1062 const_PORT = mk_const4('P', 'O', 'R', 'T'),
1063 const_PWD = mk_const3('P', 'W', 'D'),
1064 const_QUIT = mk_const4('Q', 'U', 'I', 'T'),
1065 const_REST = mk_const4('R', 'E', 'S', 'T'),
1066 const_RETR = mk_const4('R', 'E', 'T', 'R'),
1067 const_RMD = mk_const3('R', 'M', 'D'),
1068 const_RNFR = mk_const4('R', 'N', 'F', 'R'),
1069 const_RNTO = mk_const4('R', 'N', 'T', 'O'),
1070 const_SIZE = mk_const4('S', 'I', 'Z', 'E'),
1071 const_STAT = mk_const4('S', 'T', 'A', 'T'),
1072 const_STOR = mk_const4('S', 'T', 'O', 'R'),
1073 const_STOU = mk_const4('S', 'T', 'O', 'U'),
1074 const_STRU = mk_const4('S', 'T', 'R', 'U'),
1075 const_SYST = mk_const4('S', 'Y', 'S', 'T'),
1076 const_TYPE = mk_const4('T', 'Y', 'P', 'E'),
1077 const_USER = mk_const4('U', 'S', 'E', 'R'),
1083 OPT_v = (1 << ((!BB_MMU) * 2 + 0)),
1084 OPT_S = (1 << ((!BB_MMU) * 2 + 1)),
1085 OPT_w = (1 << ((!BB_MMU) * 2 + 2)) * ENABLE_FEATURE_FTP_WRITE,
1088 int ftpd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
1090 int ftpd_main(int argc, char **argv)
1092 int ftpd_main(int argc UNUSED_PARAM, char **argv)
1095 unsigned abs_timeout;
1101 abs_timeout = 1 * 60 * 60;
1104 opt_complementary = "t+:T+:vv:SS";
1106 opts = getopt32(argv, "vS" IF_FEATURE_FTP_WRITE("w") "t:T:", &G.timeout, &abs_timeout, &G.verbose, &verbose_S);
1108 opts = getopt32(argv, "l1vS" IF_FEATURE_FTP_WRITE("w") "t:T:", &G.timeout, &abs_timeout, &G.verbose, &verbose_S);
1109 if (opts & (OPT_l|OPT_1)) {
1110 /* Our secret backdoor to ls */
1111 /* TODO: pass -n too? */
1112 /* --group-directories-first would be nice, but ls don't do that yet */
1114 argv[2] = (char*)"--";
1115 /* memset(&G, 0, sizeof(G)); - ls_main does it */
1116 return ls_main(argc, argv);
1119 if (G.verbose < verbose_S)
1120 G.verbose = verbose_S;
1121 if (abs_timeout | G.timeout) {
1122 if (abs_timeout == 0)
1123 abs_timeout = INT_MAX;
1124 G.end_time = monotonic_sec() + abs_timeout;
1125 if (G.timeout > abs_timeout)
1126 G.timeout = abs_timeout;
1128 strcpy(G.msg_ok + 4, MSG_OK );
1129 strcpy(G.msg_err + 4, MSG_ERR);
1131 G.local_addr = get_sock_lsa(STDIN_FILENO);
1132 if (!G.local_addr) {
1133 /* This is confusing:
1134 * bb_error_msg_and_die("stdin is not a socket");
1137 /* Help text says that ftpd must be used as inetd service,
1138 * which is by far the most usual cause of get_sock_lsa
1142 if (!(opts & OPT_v))
1143 logmode = LOGMODE_NONE;
1145 /* LOG_NDELAY is needed since we may chroot later */
1146 openlog(applet_name, LOG_PID | LOG_NDELAY, LOG_DAEMON);
1147 logmode |= LOGMODE_SYSLOG;
1150 applet_name = xasprintf("%s[%u]", applet_name, (int)getpid());
1153 G.root_fd = xopen("/", O_RDONLY | O_DIRECTORY);
1157 xchdir(argv[optind]);
1161 //umask(077); - admin can set umask before starting us
1163 /* Signals. We'll always take -EPIPE rather than a rude signal, thanks */
1164 signal(SIGPIPE, SIG_IGN);
1166 /* Set up options on the command socket (do we need these all? why?) */
1167 setsockopt(STDIN_FILENO, IPPROTO_TCP, TCP_NODELAY, &const_int_1, sizeof(const_int_1));
1168 setsockopt(STDIN_FILENO, SOL_SOCKET, SO_KEEPALIVE, &const_int_1, sizeof(const_int_1));
1169 /* Telnet protocol over command link may send "urgent" data,
1170 * we prefer it to be received in the "normal" data stream: */
1171 setsockopt(STDIN_FILENO, SOL_SOCKET, SO_OOBINLINE, &const_int_1, sizeof(const_int_1));
1173 WRITE_OK(FTP_GREET);
1174 signal(SIGALRM, timeout_handler);
1176 #ifdef IF_WE_WANT_TO_REQUIRE_LOGIN
1178 smallint user_was_specified = 0;
1180 uint32_t cmdval = cmdio_get_cmd_and_arg();
1182 if (cmdval == const_USER) {
1183 if (G.ftp_arg == NULL || strcasecmp(G.ftp_arg, "anonymous") != 0)
1184 cmdio_write_raw(STR(FTP_LOGINERR)" Server is anonymous only\r\n");
1186 user_was_specified = 1;
1187 cmdio_write_raw(STR(FTP_GIVEPWORD)" Please specify the password\r\n");
1189 } else if (cmdval == const_PASS) {
1190 if (user_was_specified)
1192 cmdio_write_raw(STR(FTP_NEEDUSER)" Login with USER\r\n");
1193 } else if (cmdval == const_QUIT) {
1194 WRITE_OK(FTP_GOODBYE);
1197 cmdio_write_raw(STR(FTP_LOGINERR)" Login with USER and PASS\r\n");
1201 WRITE_OK(FTP_LOGINOK);
1204 /* RFC-959 Section 5.1
1205 * The following commands and options MUST be supported by every
1206 * server-FTP and user-FTP, except in cases where the underlying
1207 * file system or operating system does not allow or support
1208 * a particular command.
1209 * Type: ASCII Non-print, IMAGE, LOCAL 8
1211 * Structure: File, Record*
1212 * (Record structure is REQUIRED only for hosts whose file
1213 * systems support record structure).
1215 * USER, PASS, ACCT, [bbox: ACCT not supported]
1220 * CWD, CDUP, RMD, MKD, PWD,
1226 * "The argument field is a Telnet string identifying the user's account.
1227 * The command is not necessarily related to the USER command, as some
1228 * sites may require an account for login and others only for specific
1229 * access, such as storing files. In the latter case the command may
1230 * arrive at any time.
1231 * There are reply codes to differentiate these cases for the automation:
1232 * when account information is required for login, the response to
1233 * a successful PASSword command is reply code 332. On the other hand,
1234 * if account information is NOT required for login, the reply to
1235 * a successful PASSword command is 230; and if the account information
1236 * is needed for a command issued later in the dialogue, the server
1237 * should return a 332 or 532 reply depending on whether it stores
1238 * (pending receipt of the ACCounT command) or discards the command,
1243 uint32_t cmdval = cmdio_get_cmd_and_arg();
1245 if (cmdval == const_QUIT) {
1246 WRITE_OK(FTP_GOODBYE);
1249 else if (cmdval == const_USER)
1250 /* This would mean "ok, now give me PASS". */
1251 /*WRITE_OK(FTP_GIVEPWORD);*/
1252 /* vsftpd can be configured to not require that,
1253 * and this also saves one roundtrip:
1255 WRITE_OK(FTP_LOGINOK);
1256 else if (cmdval == const_PASS)
1257 WRITE_OK(FTP_LOGINOK);
1258 else if (cmdval == const_NOOP)
1259 WRITE_OK(FTP_NOOPOK);
1260 else if (cmdval == const_TYPE)
1261 WRITE_OK(FTP_TYPEOK);
1262 else if (cmdval == const_STRU)
1263 WRITE_OK(FTP_STRUOK);
1264 else if (cmdval == const_MODE)
1265 WRITE_OK(FTP_MODEOK);
1266 else if (cmdval == const_ALLO)
1267 WRITE_OK(FTP_ALLOOK);
1268 else if (cmdval == const_SYST)
1269 cmdio_write_raw(STR(FTP_SYSTOK)" UNIX Type: L8\r\n");
1270 else if (cmdval == const_PWD)
1272 else if (cmdval == const_CWD)
1274 else if (cmdval == const_CDUP) /* cd .. */
1276 /* HELP is nearly useless, but we can reuse FEAT for it */
1277 /* lftp uses FEAT */
1278 else if (cmdval == const_HELP || cmdval == const_FEAT)
1279 handle_feat(cmdval == const_HELP
1280 ? STRNUM32(FTP_HELP)
1281 : STRNUM32(FTP_STATOK)
1283 else if (cmdval == const_LIST) /* ls -l */
1285 else if (cmdval == const_NLST) /* "name list", bare ls */
1287 /* SIZE is crucial for wget's download indicator etc */
1288 /* Mozilla, lftp use MDTM (presumably for caching) */
1289 else if (cmdval == const_SIZE || cmdval == const_MDTM)
1290 handle_size_or_mdtm(cmdval == const_SIZE);
1291 else if (cmdval == const_STAT) {
1292 if (G.ftp_arg == NULL)
1297 else if (cmdval == const_PASV)
1299 else if (cmdval == const_EPSV)
1301 else if (cmdval == const_RETR)
1303 else if (cmdval == const_PORT)
1305 else if (cmdval == const_REST)
1307 #if ENABLE_FEATURE_FTP_WRITE
1308 else if (opts & OPT_w) {
1309 if (cmdval == const_STOR)
1311 else if (cmdval == const_MKD)
1313 else if (cmdval == const_RMD)
1315 else if (cmdval == const_DELE)
1317 else if (cmdval == const_RNFR) /* "rename from" */
1319 else if (cmdval == const_RNTO) /* "rename to" */
1321 else if (cmdval == const_APPE)
1323 else if (cmdval == const_STOU) /* "store unique" */
1330 else if (cmdval == const_STOR
1331 || cmdval == const_MKD
1332 || cmdval == const_RMD
1333 || cmdval == const_DELE
1334 || cmdval == const_RNFR
1335 || cmdval == const_RNTO
1336 || cmdval == const_APPE
1337 || cmdval == const_STOU
1339 cmdio_write_raw(STR(FTP_NOPERM)" Permission denied\r\n");
1343 /* Which unsupported commands were seen in the wild?
1344 * (doesn't necessarily mean "we must support them")
1345 * foo 1.2.3: XXXX - comment
1347 #if ENABLE_FEATURE_FTP_WRITE
1350 cmdio_write_raw(STR(FTP_BADCMD)" Unknown command\r\n");