/* * Dropbear - a SSH2 server * * Copyright (c) 2002,2003 Matt Johnston * All rights reserved. * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE * SOFTWARE. */ #include "includes.h" #include "runopts.h" #include "signkey.h" #include "buffer.h" #include "dbutil.h" #include "algo.h" #include "tcpfwd.h" #include "list.h" cli_runopts cli_opts; /* GLOBAL */ static void printhelp(); static void parse_hostname(const char* orighostarg); static void parse_multihop_hostname(const char* orighostarg, const char* argv0); static void fill_own_user(); #ifdef ENABLE_CLI_PUBKEY_AUTH static void loadidentityfile(const char* filename, int warnfail); #endif #ifdef ENABLE_CLI_ANYTCPFWD static void addforward(const char* str, m_list *fwdlist); #endif #ifdef ENABLE_CLI_NETCAT static void add_netcat(const char *str); #endif static void printhelp() { fprintf(stderr, "Dropbear SSH client v%s https://matt.ucc.asn.au/dropbear/dropbear.html\n" #ifdef ENABLE_CLI_MULTIHOP "Usage: %s [options] [user@]host[/port][,[user@]host/port],...] [command]\n" #else "Usage: %s [options] [user@]host[/port] [command]\n" #endif "-p \n" "-l \n" "-t Allocate a pty\n" "-T Don't allocate a pty\n" "-N Don't run a remote command\n" "-f Run in background after auth\n" "-y Always accept remote host key if unknown\n" "-y -y Don't perform any remote host key checking (caution)\n" "-s Request a subsystem (use by external sftp)\n" #ifdef ENABLE_CLI_PUBKEY_AUTH "-i (multiple allowed, default %s)\n" #endif #ifdef ENABLE_CLI_AGENTFWD "-A Enable agent auth forwarding\n" #endif #ifdef ENABLE_CLI_LOCALTCPFWD "-L <[listenaddress:]listenport:remotehost:remoteport> Local port forwarding\n" "-g Allow remote hosts to connect to forwarded ports\n" #endif #ifdef ENABLE_CLI_REMOTETCPFWD "-R <[listenaddress:]listenport:remotehost:remoteport> Remote port forwarding\n" #endif "-W (default %d, larger may be faster, max 1MB)\n" "-K (0 is never, default %d)\n" "-I (0 is never, default %d)\n" #ifdef ENABLE_CLI_NETCAT "-B Netcat-alike forwarding\n" #endif #ifdef ENABLE_CLI_PROXYCMD "-J Use program pipe rather than TCP connection\n" #endif #ifdef ENABLE_USER_ALGO_LIST "-c Specify preferred ciphers ('-c help' to list options)\n" "-m Specify preferred MACs for packet verification (or '-m help')\n" #endif "-V Version\n" #ifdef DEBUG_TRACE "-v verbose (compiled with DEBUG_TRACE)\n" #endif ,DROPBEAR_VERSION, cli_opts.progname, #ifdef ENABLE_CLI_PUBKEY_AUTH DROPBEAR_DEFAULT_CLI_AUTHKEY, #endif DEFAULT_RECV_WINDOW, DEFAULT_KEEPALIVE, DEFAULT_IDLE_TIMEOUT); } void cli_getopts(int argc, char ** argv) { unsigned int i, j; char ** next = 0; unsigned int cmdlen; #ifdef ENABLE_CLI_PUBKEY_AUTH int nextiskey = 0; /* A flag if the next argument is a keyfile */ #endif #ifdef ENABLE_CLI_LOCALTCPFWD int nextislocal = 0; #endif #ifdef ENABLE_CLI_REMOTETCPFWD int nextisremote = 0; #endif #ifdef ENABLE_CLI_NETCAT int nextisnetcat = 0; #endif char* dummy = NULL; /* Not used for anything real */ char* recv_window_arg = NULL; char* keepalive_arg = NULL; char* idle_timeout_arg = NULL; char *host_arg = NULL; /* see printhelp() for options */ cli_opts.progname = argv[0]; cli_opts.remotehost = NULL; cli_opts.remoteport = NULL; cli_opts.username = NULL; cli_opts.cmd = NULL; cli_opts.no_cmd = 0; cli_opts.backgrounded = 0; cli_opts.wantpty = 9; /* 9 means "it hasn't been touched", gets set later */ cli_opts.always_accept_key = 0; cli_opts.no_hostkey_check = 0; cli_opts.is_subsystem = 0; #ifdef ENABLE_CLI_PUBKEY_AUTH cli_opts.privkeys = list_new(); #endif #ifdef ENABLE_CLI_LOCALTCPFWD cli_opts.localfwds = list_new(); opts.listen_fwd_all = 0; #endif #ifdef ENABLE_CLI_REMOTETCPFWD cli_opts.remotefwds = list_new(); #endif #ifdef ENABLE_CLI_AGENTFWD cli_opts.agent_fwd = 0; cli_opts.agent_fd = -1; cli_opts.agent_keys_loaded = 0; #endif #ifdef ENABLE_CLI_PROXYCMD cli_opts.proxycmd = NULL; #endif #ifndef DISABLE_ZLIB opts.compress_mode = DROPBEAR_COMPRESS_ON; #endif #ifdef ENABLE_USER_ALGO_LIST opts.cipher_list = NULL; opts.mac_list = NULL; #endif /* not yet opts.ipv4 = 1; opts.ipv6 = 1; */ opts.recv_window = DEFAULT_RECV_WINDOW; opts.keepalive_secs = DEFAULT_KEEPALIVE; opts.idle_timeout_secs = DEFAULT_IDLE_TIMEOUT; fill_own_user(); /* Iterate all the arguments */ for (i = 1; i < (unsigned int)argc; i++) { #ifdef ENABLE_CLI_PUBKEY_AUTH if (nextiskey) { /* Load a hostkey since the previous argument was "-i" */ loadidentityfile(argv[i], 1); nextiskey = 0; continue; } #endif #ifdef ENABLE_CLI_REMOTETCPFWD if (nextisremote) { TRACE(("nextisremote true")) addforward(argv[i], cli_opts.remotefwds); nextisremote = 0; continue; } #endif #ifdef ENABLE_CLI_LOCALTCPFWD if (nextislocal) { TRACE(("nextislocal true")) addforward(argv[i], cli_opts.localfwds); nextislocal = 0; continue; } #endif #ifdef ENABLE_CLI_NETCAT if (nextisnetcat) { TRACE(("nextisnetcat true")) add_netcat(argv[i]); nextisnetcat = 0; continue; } #endif if (next) { /* The previous flag set a value to assign */ *next = argv[i]; if (*next == NULL) { dropbear_exit("Invalid null argument"); } next = NULL; continue; } if (argv[i][0] == '-') { /* A flag *waves* */ char c = argv[i][1]; if (strlen(argv[i]) != 2) { /* Ensure only one flag per hyphen. '?' falls through to print help */ c = '?'; } switch (c) { case 'y': /* always accept the remote hostkey */ if (cli_opts.always_accept_key) { /* twice means no checking at all */ cli_opts.no_hostkey_check = 1; } cli_opts.always_accept_key = 1; break; case 'p': /* remoteport */ next = &cli_opts.remoteport; break; #ifdef ENABLE_CLI_PUBKEY_AUTH case 'i': /* an identityfile */ /* Keep scp happy when it changes "-i file" to "-ifile" */ if (strlen(argv[i]) > 2) { loadidentityfile(&argv[i][2], 1); } else { nextiskey = 1; } break; #endif case 't': /* we want a pty */ cli_opts.wantpty = 1; break; case 'T': /* don't want a pty */ cli_opts.wantpty = 0; break; case 'N': cli_opts.no_cmd = 1; break; case 'f': cli_opts.backgrounded = 1; break; case 's': cli_opts.is_subsystem = 1; break; #ifdef ENABLE_CLI_LOCALTCPFWD case 'L': nextislocal = 1; break; case 'g': opts.listen_fwd_all = 1; break; #endif #ifdef ENABLE_CLI_REMOTETCPFWD case 'R': nextisremote = 1; break; #endif #ifdef ENABLE_CLI_NETCAT case 'B': nextisnetcat = 1; break; #endif #ifdef ENABLE_CLI_PROXYCMD case 'J': next = &cli_opts.proxycmd; break; #endif case 'l': next = &cli_opts.username; break; case 'h': printhelp(); exit(EXIT_SUCCESS); break; case 'u': /* backwards compatibility with old urandom option */ break; case 'W': next = &recv_window_arg; break; case 'K': next = &keepalive_arg; break; case 'I': next = &idle_timeout_arg; break; #ifdef ENABLE_CLI_AGENTFWD case 'A': cli_opts.agent_fwd = 1; break; #endif #ifdef ENABLE_USER_ALGO_LIST case 'c': next = &opts.cipher_list; break; case 'm': next = &opts.mac_list; break; #endif #ifdef DEBUG_TRACE case 'v': debug_trace = 1; break; #endif case 'F': case 'e': #ifndef ENABLE_USER_ALGO_LIST case 'c': case 'm': #endif case 'D': #ifndef ENABLE_CLI_REMOTETCPFWD case 'R': #endif #ifndef ENABLE_CLI_LOCALTCPFWD case 'L': #endif case 'V': print_version(); exit(EXIT_SUCCESS); break; case 'o': case 'b': next = &dummy; default: fprintf(stderr, "WARNING: Ignoring unknown argument '%s'\n", argv[i]); break; } /* Switch */ /* Now we handle args where they might be "-luser" (no spaces)*/ if (next && strlen(argv[i]) > 2) { *next = &argv[i][2]; next = NULL; } continue; /* next argument */ } else { TRACE(("non-flag arg: '%s'", argv[i])) /* Either the hostname or commands */ if (host_arg == NULL) { host_arg = argv[i]; } else { /* this is part of the commands to send - after this we * don't parse any more options, and flags are sent as the * command */ cmdlen = 0; for (j = i; j < (unsigned int)argc; j++) { cmdlen += strlen(argv[j]) + 1; /* +1 for spaces */ } /* Allocate the space */ cli_opts.cmd = (char*)m_malloc(cmdlen); cli_opts.cmd[0] = '\0'; /* Append all the bits */ for (j = i; j < (unsigned int)argc; j++) { strlcat(cli_opts.cmd, argv[j], cmdlen); strlcat(cli_opts.cmd, " ", cmdlen); } /* It'll be null-terminated here */ /* We've eaten all the options and flags */ break; } } } /* And now a few sanity checks and setup */ #ifdef ENABLE_USER_ALGO_LIST parse_ciphers_macs(); #endif if (host_arg == NULL) { printhelp(); exit(EXIT_FAILURE); } #ifdef ENABLE_CLI_PROXYCMD if (cli_opts.proxycmd) { /* To match the common path of m_freeing it */ cli_opts.proxycmd = m_strdup(cli_opts.proxycmd); } #endif if (cli_opts.remoteport == NULL) { cli_opts.remoteport = "22"; } /* If not explicitly specified with -t or -T, we don't want a pty if * there's a command, but we do otherwise */ if (cli_opts.wantpty == 9) { if (cli_opts.cmd == NULL) { cli_opts.wantpty = 1; } else { cli_opts.wantpty = 0; } } if (cli_opts.backgrounded && cli_opts.cmd == NULL && cli_opts.no_cmd == 0) { dropbear_exit("Command required for -f"); } if (recv_window_arg) { opts.recv_window = atol(recv_window_arg); if (opts.recv_window == 0 || opts.recv_window > MAX_RECV_WINDOW) { dropbear_exit("Bad recv window '%s'", recv_window_arg); } } if (keepalive_arg) { unsigned int val; if (m_str_to_uint(keepalive_arg, &val) == DROPBEAR_FAILURE) { dropbear_exit("Bad keepalive '%s'", keepalive_arg); } opts.keepalive_secs = val; } if (idle_timeout_arg) { unsigned int val; if (m_str_to_uint(idle_timeout_arg, &val) == DROPBEAR_FAILURE) { dropbear_exit("Bad idle_timeout '%s'", idle_timeout_arg); } opts.idle_timeout_secs = val; } #ifdef ENABLE_CLI_NETCAT if (cli_opts.cmd && cli_opts.netcat_host) { dropbear_log(LOG_INFO, "Ignoring command '%s' in netcat mode", cli_opts.cmd); } #endif #if defined(DROPBEAR_DEFAULT_CLI_AUTHKEY) && defined(ENABLE_CLI_PUBKEY_AUTH) { char *expand_path = expand_homedir_path(DROPBEAR_DEFAULT_CLI_AUTHKEY); loadidentityfile(expand_path, 0); m_free(expand_path); } #endif /* The hostname gets set up last, since * in multi-hop mode it will require knowledge * of other flags such as -i */ #ifdef ENABLE_CLI_MULTIHOP parse_multihop_hostname(host_arg, argv[0]); #else parse_hostname(host_arg); #endif } #ifdef ENABLE_CLI_PUBKEY_AUTH static void loadidentityfile(const char* filename, int warnfail) { sign_key *key; enum signkey_type keytype; TRACE(("loadidentityfile %s", filename)) key = new_sign_key(); keytype = DROPBEAR_SIGNKEY_ANY; if ( readhostkey(filename, key, &keytype) != DROPBEAR_SUCCESS ) { if (warnfail) { fprintf(stderr, "Failed loading keyfile '%s'\n", filename); } sign_key_free(key); } else { key->type = keytype; key->source = SIGNKEY_SOURCE_RAW_FILE; key->filename = m_strdup(filename); list_append(cli_opts.privkeys, key); } } #endif #ifdef ENABLE_CLI_MULTIHOP static char* multihop_passthrough_args() { char *ret; int total; unsigned int len = 0; m_list_elem *iter; /* Fill out -i, -y, -W options that make sense for all * the intermediate processes */ #ifdef ENABLE_CLI_PUBKEY_AUTH for (iter = cli_opts.privkeys->first; iter; iter = iter->next) { sign_key * key = (sign_key*)iter->item; len += 3 + strlen(key->filename); } #endif /* ENABLE_CLI_PUBKEY_AUTH */ len += 30; /* space for -W , terminator. */ ret = m_malloc(len); total = 0; if (cli_opts.no_hostkey_check) { int written = snprintf(ret+total, len-total, "-y -y "); total += written; } else if (cli_opts.always_accept_key) { int written = snprintf(ret+total, len-total, "-y "); total += written; } if (opts.recv_window != DEFAULT_RECV_WINDOW) { int written = snprintf(ret+total, len-total, "-W %d ", opts.recv_window); total += written; } #ifdef ENABLE_CLI_PUBKEY_AUTH for (iter = cli_opts.privkeys->first; iter; iter = iter->next) { sign_key * key = (sign_key*)iter->item; const size_t size = len - total; int written = snprintf(ret+total, size, "-i %s ", key->filename); dropbear_assert((unsigned int)written < size); total += written; } #endif /* ENABLE_CLI_PUBKEY_AUTH */ /* if args were passed, total will be not zero, and it will have a space at the end, so remove that */ if (total > 0) { total--; } return ret; } /* Sets up 'onion-forwarding' connections. This will spawn * a separate dbclient process for each hop. * As an example, if the cmdline is * dbclient wrt,madako,canyons * then we want to run: * dbclient -J "dbclient -B canyons:22 wrt,madako" canyons * and then the inner dbclient will recursively run: * dbclient -J "dbclient -B madako:22 wrt" madako * etc for as many hosts as we want. * * Ports for hosts can be specified as host/port. */ static void parse_multihop_hostname(const char* orighostarg, const char* argv0) { char *userhostarg = NULL; char *hostbuf = NULL; char *last_hop = NULL; char *remainder = NULL; /* both scp and rsync parse a user@host argument * and turn it into "-l user host". This breaks * for our multihop syntax, so we suture it back together. * This will break usernames that have both '@' and ',' in them, * though that should be fairly uncommon. */ if (cli_opts.username && strchr(cli_opts.username, ',') && strchr(cli_opts.username, '@')) { unsigned int len = strlen(orighostarg) + strlen(cli_opts.username) + 2; hostbuf = m_malloc(len); snprintf(hostbuf, len, "%s@%s", cli_opts.username, orighostarg); } else { hostbuf = m_strdup(orighostarg); } userhostarg = hostbuf; last_hop = strrchr(userhostarg, ','); if (last_hop) { if (last_hop == userhostarg) { dropbear_exit("Bad multi-hop hostnames"); } *last_hop = '\0'; last_hop++; remainder = userhostarg; userhostarg = last_hop; } parse_hostname(userhostarg); if (last_hop) { /* Set up the proxycmd */ unsigned int cmd_len = 0; char *passthrough_args = multihop_passthrough_args(); if (cli_opts.proxycmd) { dropbear_exit("-J can't be used with multihop mode"); } if (cli_opts.remoteport == NULL) { cli_opts.remoteport = "22"; } cmd_len = strlen(argv0) + strlen(remainder) + strlen(cli_opts.remotehost) + strlen(cli_opts.remoteport) + strlen(passthrough_args) + 30; cli_opts.proxycmd = m_malloc(cmd_len); snprintf(cli_opts.proxycmd, cmd_len, "%s -B %s:%s %s %s", argv0, cli_opts.remotehost, cli_opts.remoteport, passthrough_args, remainder); #ifndef DISABLE_ZLIB /* The stream will be incompressible since it's encrypted. */ opts.compress_mode = DROPBEAR_COMPRESS_OFF; #endif m_free(passthrough_args); } m_free(hostbuf); } #endif /* !ENABLE_CLI_MULTIHOP */ /* Parses a [user@]hostname[/port] argument. */ static void parse_hostname(const char* orighostarg) { char *userhostarg = NULL; char *port = NULL; userhostarg = m_strdup(orighostarg); cli_opts.remotehost = strchr(userhostarg, '@'); if (cli_opts.remotehost == NULL) { /* no username portion, the cli-auth.c code can figure the * local user's name */ cli_opts.remotehost = userhostarg; } else { cli_opts.remotehost[0] = '\0'; /* Split the user/host */ cli_opts.remotehost++; cli_opts.username = userhostarg; } if (cli_opts.username == NULL) { cli_opts.username = m_strdup(cli_opts.own_user); } port = strchr(cli_opts.remotehost, '^'); if (!port) { /* legacy separator */ port = strchr(cli_opts.remotehost, '/'); } if (port) { *port = '\0'; cli_opts.remoteport = port+1; } if (cli_opts.remotehost[0] == '\0') { dropbear_exit("Bad hostname"); } } #ifdef ENABLE_CLI_NETCAT static void add_netcat(const char* origstr) { char *portstr = NULL; char * str = m_strdup(origstr); portstr = strchr(str, ':'); if (portstr == NULL) { TRACE(("No netcat port")) goto fail; } *portstr = '\0'; portstr++; if (strchr(portstr, ':')) { TRACE(("Multiple netcat colons")) goto fail; } if (m_str_to_uint(portstr, &cli_opts.netcat_port) == DROPBEAR_FAILURE) { TRACE(("bad netcat port")) goto fail; } if (cli_opts.netcat_port > 65535) { TRACE(("too large netcat port")) goto fail; } cli_opts.netcat_host = str; return; fail: dropbear_exit("Bad netcat endpoint '%s'", origstr); } #endif static void fill_own_user() { uid_t uid; struct passwd *pw = NULL; uid = getuid(); pw = getpwuid(uid); if (pw && pw->pw_name != NULL) { cli_opts.own_user = m_strdup(pw->pw_name); } else { dropbear_log(LOG_INFO, "Warning: failed to identify current user. Trying anyway."); cli_opts.own_user = m_strdup("unknown"); } } #ifdef ENABLE_CLI_ANYTCPFWD /* Turn a "[listenaddr:]listenport:remoteaddr:remoteport" string into into a forwarding * set, and add it to the forwarding list */ static void addforward(const char* origstr, m_list *fwdlist) { char *part1 = NULL, *part2 = NULL, *part3 = NULL, *part4 = NULL; char * listenaddr = NULL; char * listenport = NULL; char * connectaddr = NULL; char * connectport = NULL; struct TCPFwdEntry* newfwd = NULL; char * str = NULL; TRACE(("enter addforward")) /* We need to split the original argument up. This var is never free()d. */ str = m_strdup(origstr); part1 = str; part2 = strchr(str, ':'); if (part2 == NULL) { TRACE(("part2 == NULL")) goto fail; } *part2 = '\0'; part2++; part3 = strchr(part2, ':'); if (part3 == NULL) { TRACE(("part3 == NULL")) goto fail; } *part3 = '\0'; part3++; part4 = strchr(part3, ':'); if (part4) { *part4 = '\0'; part4++; } if (part4) { listenaddr = part1; listenport = part2; connectaddr = part3; connectport = part4; } else { listenaddr = NULL; listenport = part1; connectaddr = part2; connectport = part3; } newfwd = m_malloc(sizeof(struct TCPFwdEntry)); /* Now we check the ports - note that the port ints are unsigned, * the check later only checks for >= MAX_PORT */ if (m_str_to_uint(listenport, &newfwd->listenport) == DROPBEAR_FAILURE) { TRACE(("bad listenport strtoul")) goto fail; } if (m_str_to_uint(connectport, &newfwd->connectport) == DROPBEAR_FAILURE) { TRACE(("bad connectport strtoul")) goto fail; } newfwd->listenaddr = listenaddr; newfwd->connectaddr = connectaddr; if (newfwd->listenport > 65535) { TRACE(("listenport > 65535")) goto badport; } if (newfwd->connectport > 65535) { TRACE(("connectport > 65535")) goto badport; } newfwd->have_reply = 0; list_append(fwdlist, newfwd); TRACE(("leave addforward: done")) return; fail: dropbear_exit("Bad TCP forward '%s'", origstr); badport: dropbear_exit("Bad TCP port in '%s'", origstr); } #endif