X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=networking%2Fftpd.c;h=33db964fa46c465b72bda6fa75c65adee1873ee0;hb=a8816dafc4b274b17c58df88cabdbf9e2b47f528;hp=b295ddf4f4e38fa98732d19f9aebb63d0d24ca0d;hpb=1432cb4bd9daf304111dd19e0011f8756c32e327;p=oweals%2Fbusybox.git diff --git a/networking/ftpd.c b/networking/ftpd.c index b295ddf4f..33db964fa 100644 --- a/networking/ftpd.c +++ b/networking/ftpd.c @@ -4,7 +4,7 @@ * * Author: Adam Tkac * - * Licensed under GPLv2, see file LICENSE in this tarball for details. + * Licensed under GPLv2, see file LICENSE in this source tree. * * Only subset of FTP protocol is implemented but vast majority of clients * should not have any problem. @@ -12,6 +12,22 @@ * You have to run this daemon via inetd. */ +//usage:#define ftpd_trivial_usage +//usage: "[-wvS] [-t N] [-T N] [DIR]" +//usage:#define ftpd_full_usage "\n\n" +//usage: "Anonymous FTP server\n" +//usage: "\n" +//usage: "ftpd should be used as an inetd service.\n" +//usage: "ftpd's line for inetd.conf:\n" +//usage: " 21 stream tcp nowait root ftpd ftpd /files/to/serve\n" +//usage: "It also can be ran from tcpsvd:\n" +//usage: " tcpsvd -vE 0.0.0.0 21 ftpd /files/to/serve\n" +//usage: "\n -w Allow upload" +//usage: "\n -v Log errors to stderr. -vv: verbose log" +//usage: "\n -S Log errors to syslog. -SS: verbose log" +//usage: "\n -t,-T Idle and absolute timeouts" +//usage: "\n DIR Change root to this directory" + #include "libbb.h" #include #include @@ -87,7 +103,9 @@ enum { struct globals { int pasv_listen_fd; - int proc_self_fd; +#if !BB_MMU + int root_fd; +#endif int local_file_fd; unsigned end_time; unsigned timeout; @@ -104,7 +122,7 @@ struct globals { /* We need these aligned to uint32_t */ char msg_ok [(sizeof("NNN " MSG_OK ) + 3) & 0xfffc]; char msg_err[(sizeof("NNN " MSG_ERR) + 3) & 0xfffc]; -}; +} FIX_ALIASING; #define G (*(struct globals*)&bb_common_bufsiz1) #define INIT_G() do { \ /* Moved to main */ \ @@ -204,7 +222,7 @@ cmdio_write_error(unsigned status) { *(uint32_t *) G.msg_err = status; xwrite(STDOUT_FILENO, G.msg_err, sizeof("NNN " MSG_ERR) - 1); - if (G.verbose > 1) + if (G.verbose > 0) verbose_log(G.msg_err); } #define WRITE_ERR(a) cmdio_write_error(STRNUM32sp(a)) @@ -282,7 +300,7 @@ handle_cdup(void) static void handle_stat(void) { - cmdio_write_raw(STR(FTP_STATOK)"-FTP server status:\r\n" + cmdio_write_raw(STR(FTP_STATOK)"-Server status:\r\n" " TYPE: BINARY\r\n" STR(FTP_STATOK)" Ok\r\n"); } @@ -395,7 +413,7 @@ static int port_or_pasv_was_seen(void) { if (!pasv_active() && !port_active()) { - cmdio_write_raw(STR(FTP_BADSENDCONN)" Use PORT or PASV first\r\n"); + cmdio_write_raw(STR(FTP_BADSENDCONN)" Use PORT/PASV first\r\n"); return 0; } @@ -414,7 +432,7 @@ bind_for_passive_mode(void) G.pasv_listen_fd = fd = xsocket(G.local_addr->u.sa.sa_family, SOCK_STREAM, 0); setsockopt_reuseaddr(fd); - set_nport(G.local_addr, 0); + set_nport(&G.local_addr->u.sa, 0); xbind(fd, &G.local_addr->u.sa, G.local_addr->len); xlisten(fd, 1); getsockname(fd, &G.local_addr->u.sa, &G.local_addr->len); @@ -439,7 +457,7 @@ handle_pasv(void) addr = xstrdup("0.0.0.0"); replace_char(addr, '.', ','); - response = xasprintf(STR(FTP_PASVOK)" Entering Passive Mode (%s,%u,%u)\r\n", + response = xasprintf(STR(FTP_PASVOK)" PASV ok (%s,%u,%u)\r\n", addr, (int)(port >> 8), (int)(port & 255)); free(addr); cmdio_write_raw(response); @@ -454,26 +472,11 @@ handle_epsv(void) char *response; port = bind_for_passive_mode(); - response = xasprintf(STR(FTP_EPSVOK)" EPSV Ok (|||%u|)\r\n", port); + response = xasprintf(STR(FTP_EPSVOK)" EPSV ok (|||%u|)\r\n", port); cmdio_write_raw(response); free(response); } -/* libbb candidate */ -static -len_and_sockaddr* get_peer_lsa(int fd) -{ - len_and_sockaddr *lsa; - socklen_t len = 0; - - if (getpeername(fd, NULL, &len) != 0) - return NULL; - lsa = xzalloc(LSA_LEN_SIZE + len); - lsa->len = len; - getpeername(fd, &lsa->u.sa, &lsa->len); - return lsa; -} - static void handle_port(void) { @@ -538,7 +541,7 @@ handle_port(void) G.port_addr = xdotted2sockaddr(raw, port); #else G.port_addr = get_peer_lsa(STDIN_FILENO); - set_nport(G.port_addr, htons(port)); + set_nport(&G.port_addr->u.sa, htons(port)); #endif WRITE_OK(FTP_PORTOK); } @@ -547,7 +550,7 @@ static void handle_rest(void) { /* When ftp_arg == NULL simply restart from beginning */ - G.restart_pos = G.ftp_arg ? xatoi_u(G.ftp_arg) : 0; + G.restart_pos = G.ftp_arg ? xatoi_positive(G.ftp_arg) : 0; WRITE_OK(FTP_RESTOK); } @@ -590,7 +593,7 @@ handle_retr(void) xlseek(local_file_fd, offset, SEEK_SET); response = xasprintf( - " Opening BINARY mode data connection for %s (%"OFF_FMT"u bytes)", + " Opening BINARY connection for %s (%"OFF_FMT"u bytes)", G.ftp_arg, statbuf.st_size); remote_fd = get_remote_transfer_fd(response); free(response); @@ -614,39 +617,76 @@ handle_retr(void) static int popen_ls(const char *opt) { - char *cwd; - const char *argv[5] = { "ftpd", opt, NULL, G.ftp_arg, NULL }; + const char *argv[5]; struct fd_pair outfd; pid_t pid; - cwd = xrealloc_getcwd_or_warn(NULL); + argv[0] = "ftpd"; + argv[1] = opt; /* "-l" or "-1" */ +#if BB_MMU + argv[2] = "--"; +#else + /* NOMMU ftpd ls helper chdirs to argv[2], + * preventing peer from seeing real root. */ + argv[2] = xrealloc_getcwd_or_warn(NULL); +#endif + argv[3] = G.ftp_arg; + argv[4] = NULL; + + /* Improve compatibility with non-RFC conforming FTP clients + * which send e.g. "LIST -l", "LIST -la", "LIST -aL". + * See https://bugs.kde.org/show_bug.cgi?id=195578 */ + if (ENABLE_FEATURE_FTPD_ACCEPT_BROKEN_LIST + && G.ftp_arg && G.ftp_arg[0] == '-' + ) { + const char *tmp = strchr(G.ftp_arg, ' '); + if (tmp) /* skip the space */ + tmp++; + argv[3] = tmp; + } + xpiped_pair(outfd); - /*fflush(NULL); - so far we dont use stdio on output */ - pid = vfork(); - switch (pid) { - case -1: /* failure */ - bb_perror_msg_and_die("vfork"); - case 0: /* child */ - /* NB: close _first_, then move fds! */ + /*fflush_all(); - so far we dont use stdio on output */ + pid = BB_MMU ? xfork() : xvfork(); + if (pid == 0) { + /* child */ +#if !BB_MMU + /* On NOMMU, we want to execute a child - copy of ourself. + * In chroot we usually can't do it. Thus we chdir + * out of the chroot back to original root, + * and (see later below) execute bb_busybox_exec_path + * relative to current directory */ + if (fchdir(G.root_fd) != 0) + _exit(127); + /*close(G.root_fd); - close_on_exec_on() took care of this */ +#endif + /* NB: close _first_, then move fd! */ close(outfd.rd); xmove_fd(outfd.wr, STDOUT_FILENO); + /* Opening /dev/null in chroot is hard. + * Just making sure STDIN_FILENO is opened + * to something harmless. Paranoia, + * ls won't read it anyway */ close(STDIN_FILENO); - /* xopen("/dev/null", O_RDONLY); - chroot may lack it! */ - if (fchdir(G.proc_self_fd) == 0) { - close(G.proc_self_fd); - argv[2] = cwd; - /* ftpd ls helper chdirs to argv[2], - * preventing peer from seeing /proc/self - */ - execv("exe", (char**) argv); - } + dup(STDOUT_FILENO); /* copy will become STDIN_FILENO */ +#if BB_MMU + /* memset(&G, 0, sizeof(G)); - ls_main does it */ + exit(ls_main(ARRAY_SIZE(argv) - 1, (char**) argv)); +#else + /* + 1: we must use relative path here if in chroot. + * For example, execv("/proc/self/exe") will fail, since + * it looks for "/proc/self/exe" _relative to chroot!_ */ + execv(bb_busybox_exec_path + 1, (char**) argv); _exit(127); +#endif } /* parent */ close(outfd.wr); - free(cwd); +#if !BB_MMU + free((char*)argv[2]); +#endif return outfd.rd; } @@ -668,27 +708,28 @@ handle_dir_common(int opts) /* -n prevents user/groupname display, * which can be problematic in chroot */ ls_fd = popen_ls((opts & LONG_LISTING) ? "-l" : "-1"); - ls_fp = fdopen(ls_fd, "r"); - if (!ls_fp) /* never happens. paranoia */ - bb_perror_msg_and_die("fdopen"); + ls_fp = xfdopen_for_read(ls_fd); if (opts & USE_CTRL_CONN) { /* STAT */ - cmdio_write_raw(STR(FTP_STATFILE_OK)"-Status follows:\r\n"); + cmdio_write_raw(STR(FTP_STATFILE_OK)"-File status:\r\n"); while (1) { - line = xmalloc_fgetline(ls_fp); + line = xmalloc_fgetline(ls_fp); if (!line) break; - cmdio_write(0, line); /* hack: 0 results in no status at all */ + /* Hack: 0 results in no status at all */ + /* Note: it's ok that we don't prepend space, + * ftp.kernel.org doesn't do that too */ + cmdio_write(0, line); free(line); } WRITE_OK(FTP_STATFILE_OK); } else { /* LIST/NLST [] */ - int remote_fd = get_remote_transfer_fd(" Here comes the directory listing"); + int remote_fd = get_remote_transfer_fd(" Directory listing"); if (remote_fd >= 0) { while (1) { - line = xmalloc_fgetline(ls_fp); + line = xmalloc_fgetline(ls_fp); if (!line) break; /* I've seen clients complaining when they @@ -780,7 +821,7 @@ handle_size_or_mdtm(int need_size) gmtime_r(&statbuf.st_mtime, &broken_out); sprintf(buf, STR(FTP_STATFILE_OK)" %04u%02u%02u%02u%02u%02u\r\n", broken_out.tm_year + 1900, - broken_out.tm_mon, + broken_out.tm_mon + 1, broken_out.tm_mday, broken_out.tm_hour, broken_out.tm_min, @@ -837,7 +878,7 @@ handle_rnto(void) /* If we didn't get a RNFR, throw a wobbly */ if (G.rnfr_filename == NULL || G.ftp_arg == NULL) { - cmdio_write_raw(STR(FTP_NEEDRNFR)" RNFR required first\r\n"); + cmdio_write_raw(STR(FTP_NEEDRNFR)" Use RNFR first\r\n"); return; } @@ -886,6 +927,7 @@ handle_upload_common(int is_append, int is_unique) || fstat(local_file_fd, &statbuf) != 0 || !S_ISREG(statbuf.st_mode) ) { + free(tempname); WRITE_ERR(FTP_UPLOADFAIL); if (local_file_fd >= 0) goto close_local_and_bail; @@ -938,22 +980,74 @@ handle_stou(void) static uint32_t cmdio_get_cmd_and_arg(void) { - size_t len; + int len; uint32_t cmdval; char *cmd; alarm(G.timeout); free(G.ftp_cmd); - len = 8 * 1024; /* Paranoia. Peer may send 1 gigabyte long cmd... */ - G.ftp_cmd = cmd = xmalloc_reads(STDIN_FILENO, NULL, &len); - if (!cmd) - exit(0); + { + /* Paranoia. Peer may send 1 gigabyte long cmd... */ + /* Using separate len_on_stk instead of len optimizes + * code size (allows len to be in CPU register) */ + size_t len_on_stk = 8 * 1024; + G.ftp_cmd = cmd = xmalloc_fgets_str_len(stdin, "\r\n", &len_on_stk); + if (!cmd) + exit(0); + len = len_on_stk; + } - /* Trailing '\n' is already stripped, strip '\r' */ - len = strlen(cmd) - 1; - if ((ssize_t)len >= 0 && cmd[len] == '\r') - cmd[len--] = '\0'; + /* De-escape telnet: 0xff,0xff => 0xff */ + /* RFC959 says that ABOR, STAT, QUIT may be sent even during + * data transfer, and may be preceded by telnet's "Interrupt Process" + * code (two-byte sequence 255,244) and then by telnet "Synch" code + * 255,242 (byte 242 is sent with TCP URG bit using send(MSG_OOB) + * and may generate SIGURG on our side. See RFC854). + * So far we don't support that (may install SIGURG handler if we'd want to), + * but we need to at least remove 255,xxx pairs. lftp sends those. */ + /* Then de-escape FTP: NUL => '\n' */ + /* Testing for \xff: + * Create file named '\xff': echo Hello >`echo -ne "\xff"` + * Try to get it: ftpget -v 127.0.0.1 Eff `echo -ne "\xff\xff"` + * (need "\xff\xff" until ftpget applet is fixed to do escaping :) + * Testing for embedded LF: + * LF_HERE=`echo -ne "LF\nHERE"` + * echo Hello >"$LF_HERE" + * ftpget -v 127.0.0.1 LF_HERE "$LF_HERE" + */ + { + int dst, src; + + /* Strip "\r\n" if it is there */ + if (len != 0 && cmd[len - 1] == '\n') { + len--; + if (len != 0 && cmd[len - 1] == '\r') + len--; + cmd[len] = '\0'; + } + src = strchrnul(cmd, 0xff) - cmd; + /* 99,99% there are neither NULs nor 255s and src == len */ + if (src < len) { + dst = src; + do { + if ((unsigned char)(cmd[src]) == 255) { + src++; + /* 255,xxx - skip 255 */ + if ((unsigned char)(cmd[src]) != 255) { + /* 255,!255 - skip both */ + src++; + continue; + } + /* 255,255 - retain one 255 */ + } + /* NUL => '\n' */ + cmd[dst++] = cmd[src] ? cmd[src] : '\n'; + src++; + } while (src < len); + cmd[dst] = '\0'; + } + } if (G.verbose > 1) verbose_log(cmd); @@ -1006,34 +1100,49 @@ enum { const_TYPE = mk_const4('T', 'Y', 'P', 'E'), const_USER = mk_const4('U', 'S', 'E', 'R'), +#if !BB_MMU OPT_l = (1 << 0), OPT_1 = (1 << 1), - OPT_v = (1 << 2), - OPT_S = (1 << 3), - OPT_w = (1 << 4), +#endif + OPT_v = (1 << ((!BB_MMU) * 2 + 0)), + OPT_S = (1 << ((!BB_MMU) * 2 + 1)), + OPT_w = (1 << ((!BB_MMU) * 2 + 2)) * ENABLE_FEATURE_FTP_WRITE, }; int ftpd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; +#if !BB_MMU int ftpd_main(int argc, char **argv) +#else +int ftpd_main(int argc UNUSED_PARAM, char **argv) +#endif { unsigned abs_timeout; + unsigned verbose_S; smallint opts; INIT_G(); abs_timeout = 1 * 60 * 60; + verbose_S = 0; G.timeout = 2 * 60; - opt_complementary = "t+:T+:vv"; - opts = getopt32(argv, "l1vS" USE_FEATURE_FTP_WRITE("w") "t:T:", &G.timeout, &abs_timeout, &G.verbose); + opt_complementary = "t+:T+:vv:SS"; +#if BB_MMU + opts = getopt32(argv, "vS" IF_FEATURE_FTP_WRITE("w") "t:T:", &G.timeout, &abs_timeout, &G.verbose, &verbose_S); +#else + opts = getopt32(argv, "l1vS" IF_FEATURE_FTP_WRITE("w") "t:T:", &G.timeout, &abs_timeout, &G.verbose, &verbose_S); if (opts & (OPT_l|OPT_1)) { /* Our secret backdoor to ls */ - memset(&G, 0, sizeof(G)); -/* TODO: pass -n too? */ -/* --group-directories-first would be nice, but ls don't do that yet */ +/* TODO: pass -n? It prevents user/group resolution, which may not work in chroot anyway */ +/* TODO: pass -A? It shows dot files */ +/* TODO: pass --group-directories-first? would be nice, but ls doesn't do that yet */ xchdir(argv[2]); argv[2] = (char*)"--"; + /* memset(&G, 0, sizeof(G)); - ls_main does it */ return ls_main(argc, argv); } +#endif + if (G.verbose < verbose_S) + G.verbose = verbose_S; if (abs_timeout | G.timeout) { if (abs_timeout == 0) abs_timeout = INT_MAX; @@ -1065,11 +1174,13 @@ int ftpd_main(int argc, char **argv) if (logmode) applet_name = xasprintf("%s[%u]", applet_name, (int)getpid()); - G.proc_self_fd = xopen("/proc/self", O_RDONLY | O_DIRECTORY); +#if !BB_MMU + G.root_fd = xopen("/", O_RDONLY | O_DIRECTORY); + close_on_exec_on(G.root_fd); +#endif if (argv[optind]) { - xchdir(argv[optind]); - chroot("."); + xchroot(argv[optind]); } //umask(077); - admin can set umask before starting us @@ -1080,6 +1191,8 @@ int ftpd_main(int argc, char **argv) /* Set up options on the command socket (do we need these all? why?) */ setsockopt(STDIN_FILENO, IPPROTO_TCP, TCP_NODELAY, &const_int_1, sizeof(const_int_1)); setsockopt(STDIN_FILENO, SOL_SOCKET, SO_KEEPALIVE, &const_int_1, sizeof(const_int_1)); + /* Telnet protocol over command link may send "urgent" data, + * we prefer it to be received in the "normal" data stream: */ setsockopt(STDIN_FILENO, SOL_SOCKET, SO_OOBINLINE, &const_int_1, sizeof(const_int_1)); WRITE_OK(FTP_GREET); @@ -1234,6 +1347,8 @@ int ftpd_main(int argc, char **argv) handle_appe(); else if (cmdval == const_STOU) /* "store unique" */ handle_stou(); + else + goto bad_cmd; } #endif #if 0 @@ -1254,6 +1369,9 @@ int ftpd_main(int argc, char **argv) * (doesn't necessarily mean "we must support them") * foo 1.2.3: XXXX - comment */ +#if ENABLE_FEATURE_FTP_WRITE + bad_cmd: +#endif cmdio_write_raw(STR(FTP_BADCMD)" Unknown command\r\n"); } }