Annotation of src/usr.bin/ssh/ssh.c, Revision 1.45
1.1 deraadt 1: /*
1.32 deraadt 2: * Author: Tatu Ylonen <ylo@cs.hut.fi>
3: * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
4: * All rights reserved
5: * Created: Sat Mar 18 16:36:11 1995 ylo
6: * Ssh client program. This program can be used to log into a remote machine.
7: * The software supports strong authentication, encryption, and forwarding
8: * of X11, TCP/IP, and authentication connections.
9: *
10: * Modified to work with SSL by Niels Provos <provos@citi.umich.edu> in Canada.
11: */
1.1 deraadt 12:
13: #include "includes.h"
1.45 ! markus 14: RCSID("$Id: ssh.c,v 1.44 2000/03/28 20:31:28 markus Exp $");
1.1 deraadt 15:
16: #include "xmalloc.h"
17: #include "ssh.h"
18: #include "packet.h"
19: #include "buffer.h"
20: #include "authfd.h"
21: #include "readconf.h"
22: #include "uidswap.h"
1.45 ! markus 23:
! 24: #include "ssh2.h"
! 25: #include "compat.h"
1.44 markus 26: #include "channels.h"
1.1 deraadt 27:
1.37 markus 28: /* Flag indicating whether IPv4 or IPv6. This can be set on the command line.
29: Default value is AF_UNSPEC means both IPv4 and IPv6. */
30: int IPv4or6 = AF_UNSPEC;
31:
1.31 markus 32: /* Flag indicating whether debug mode is on. This can be set on the command line. */
1.1 deraadt 33: int debug_flag = 0;
34:
35: int tty_flag = 0;
36:
1.45 ! markus 37: /* don't exec a shell */
! 38: int no_shell_flag = 0;
! 39: int no_tty_flag = 0;
! 40:
1.33 markus 41: /*
42: * Flag indicating that nothing should be read from stdin. This can be set
43: * on the command line.
44: */
1.1 deraadt 45: int stdin_null_flag = 0;
46:
1.33 markus 47: /*
48: * Flag indicating that ssh should fork after authentication. This is useful
49: * so that the pasphrase can be entered manually, and then ssh goes to the
50: * background.
51: */
1.1 deraadt 52: int fork_after_authentication_flag = 0;
53:
1.33 markus 54: /*
55: * General data structure for command line options and options configurable
56: * in configuration files. See readconf.h.
57: */
1.1 deraadt 58: Options options;
59:
1.33 markus 60: /*
61: * Name of the host we are connecting to. This is the name given on the
62: * command line, or the HostName specified for the user-supplied name in a
63: * configuration file.
64: */
1.1 deraadt 65: char *host;
66:
1.22 provos 67: /* socket address the host resolves to */
1.37 markus 68: struct sockaddr_storage hostaddr;
1.22 provos 69:
1.33 markus 70: /*
71: * Flag to indicate that we have received a window change signal which has
72: * not yet been processed. This will cause a message indicating the new
73: * window size to be sent to the server a little later. This is volatile
74: * because this is updated in a signal handler.
75: */
1.1 deraadt 76: volatile int received_window_change_signal = 0;
77:
78: /* Value of argv[0] (set in the main program). */
79: char *av0;
80:
81: /* Flag indicating whether we have a valid host private key loaded. */
82: int host_private_key_loaded = 0;
83:
84: /* Host private key. */
1.2 provos 85: RSA *host_private_key = NULL;
1.1 deraadt 86:
1.10 dugsong 87: /* Original real UID. */
88: uid_t original_real_uid;
1.1 deraadt 89:
1.45 ! markus 90: /* command to be executed */
! 91: Buffer command;
! 92:
1.1 deraadt 93: /* Prints a help message to the user. This function never returns. */
94:
1.2 provos 95: void
96: usage()
1.1 deraadt 97: {
1.31 markus 98: fprintf(stderr, "Usage: %s [options] host [command]\n", av0);
99: fprintf(stderr, "Options:\n");
100: fprintf(stderr, " -l user Log in using this user name.\n");
101: fprintf(stderr, " -n Redirect input from /dev/null.\n");
102: fprintf(stderr, " -a Disable authentication agent forwarding.\n");
1.9 dugsong 103: #ifdef AFS
1.31 markus 104: fprintf(stderr, " -k Disable Kerberos ticket and AFS token forwarding.\n");
105: #endif /* AFS */
106: fprintf(stderr, " -x Disable X11 connection forwarding.\n");
107: fprintf(stderr, " -i file Identity for RSA authentication (default: ~/.ssh/identity).\n");
108: fprintf(stderr, " -t Tty; allocate a tty even if command is given.\n");
1.45 ! markus 109: fprintf(stderr, " -T Do not allocate a tty.\n");
1.31 markus 110: fprintf(stderr, " -v Verbose; display verbose debugging messages.\n");
111: fprintf(stderr, " -V Display version number only.\n");
112: fprintf(stderr, " -P Don't allocate a privileged port.\n");
113: fprintf(stderr, " -q Quiet; don't display any warning messages.\n");
114: fprintf(stderr, " -f Fork into background after authentication.\n");
115: fprintf(stderr, " -e char Set escape character; ``none'' = disable (default: ~).\n");
116:
117: fprintf(stderr, " -c cipher Select encryption algorithm: "
118: "``3des'', "
119: "``blowfish''\n");
120: fprintf(stderr, " -p port Connect to this port. Server must be on the same port.\n");
121: fprintf(stderr, " -L listen-port:host:port Forward local port to remote address\n");
122: fprintf(stderr, " -R listen-port:host:port Forward remote port to local address\n");
123: fprintf(stderr, " These cause %s to listen for connections on a port, and\n", av0);
124: fprintf(stderr, " forward them to the other side by connecting to host:port.\n");
125: fprintf(stderr, " -C Enable compression.\n");
1.45 ! markus 126: fprintf(stderr, " -N Do not execute a shell or command.\n");
1.31 markus 127: fprintf(stderr, " -g Allow remote hosts to connect to forwarded ports.\n");
1.37 markus 128: fprintf(stderr, " -4 Use IPv4 only.\n");
129: fprintf(stderr, " -6 Use IPv6 only.\n");
1.31 markus 130: fprintf(stderr, " -o 'option' Process the option as if it was read from a configuration file.\n");
131: exit(1);
1.1 deraadt 132: }
133:
1.32 deraadt 134: /*
135: * Connects to the given host using rsh (or prints an error message and exits
136: * if rsh is not available). This function never returns.
137: */
1.2 provos 138: void
1.31 markus 139: rsh_connect(char *host, char *user, Buffer * command)
1.1 deraadt 140: {
1.31 markus 141: char *args[10];
142: int i;
143:
144: log("Using rsh. WARNING: Connection will not be encrypted.");
145: /* Build argument list for rsh. */
146: i = 0;
147: args[i++] = _PATH_RSH;
148: /* host may have to come after user on some systems */
149: args[i++] = host;
150: if (user) {
151: args[i++] = "-l";
152: args[i++] = user;
153: }
154: if (buffer_len(command) > 0) {
155: buffer_append(command, "\0", 1);
156: args[i++] = buffer_ptr(command);
157: }
158: args[i++] = NULL;
159: if (debug_flag) {
160: for (i = 0; args[i]; i++) {
161: if (i != 0)
162: fprintf(stderr, " ");
163: fprintf(stderr, "%s", args[i]);
164: }
165: fprintf(stderr, "\n");
166: }
167: execv(_PATH_RSH, args);
168: perror(_PATH_RSH);
169: exit(1);
1.1 deraadt 170: }
171:
1.45 ! markus 172: int ssh_session(void);
! 173: int ssh_session2(void);
! 174:
1.32 deraadt 175: /*
176: * Main program for the ssh client.
177: */
1.2 provos 178: int
179: main(int ac, char **av)
1.1 deraadt 180: {
1.45 ! markus 181: int i, opt, optind, exit_status, ok;
1.35 markus 182: u_short fwd_port, fwd_host_port;
1.31 markus 183: char *optarg, *cp, buf[256];
184: struct stat st;
185: struct passwd *pw, pwcopy;
1.45 ! markus 186: int dummy;
1.31 markus 187: uid_t original_effective_uid;
188:
1.33 markus 189: /*
190: * Save the original real uid. It will be needed later (uid-swapping
191: * may clobber the real uid).
192: */
1.31 markus 193: original_real_uid = getuid();
194: original_effective_uid = geteuid();
195:
196: /* If we are installed setuid root be careful to not drop core. */
197: if (original_real_uid != original_effective_uid) {
198: struct rlimit rlim;
199: rlim.rlim_cur = rlim.rlim_max = 0;
200: if (setrlimit(RLIMIT_CORE, &rlim) < 0)
201: fatal("setrlimit failed: %.100s", strerror(errno));
1.1 deraadt 202: }
1.33 markus 203: /*
204: * Use uid-swapping to give up root privileges for the duration of
205: * option processing. We will re-instantiate the rights when we are
206: * ready to create the privileged port, and will permanently drop
207: * them when the port has been created (actually, when the connection
208: * has been made, as we may need to create the port several times).
209: */
1.31 markus 210: temporarily_use_uid(original_real_uid);
211:
1.33 markus 212: /*
213: * Set our umask to something reasonable, as some files are created
214: * with the default umask. This will make them world-readable but
215: * writable only by the owner, which is ok for all files for which we
216: * don't set the modes explicitly.
217: */
1.31 markus 218: umask(022);
219:
220: /* Save our own name. */
221: av0 = av[0];
222:
223: /* Initialize option structure to indicate that no values have been set. */
224: initialize_options(&options);
225:
226: /* Parse command-line arguments. */
227: host = NULL;
228:
229: /* If program name is not one of the standard names, use it as host name. */
230: if (strchr(av0, '/'))
231: cp = strrchr(av0, '/') + 1;
232: else
233: cp = av0;
234: if (strcmp(cp, "rsh") != 0 && strcmp(cp, "ssh") != 0 &&
235: strcmp(cp, "rlogin") != 0 && strcmp(cp, "slogin") != 0)
236: host = cp;
237:
238: for (optind = 1; optind < ac; optind++) {
239: if (av[optind][0] != '-') {
240: if (host)
241: break;
242: if ((cp = strchr(av[optind], '@'))) {
1.38 markus 243: if(cp == av[optind])
244: usage();
1.31 markus 245: options.user = av[optind];
246: *cp = '\0';
247: host = ++cp;
248: } else
249: host = av[optind];
250: continue;
251: }
252: opt = av[optind][1];
253: if (!opt)
254: usage();
255: if (strchr("eilcpLRo", opt)) { /* options with arguments */
256: optarg = av[optind] + 2;
257: if (strcmp(optarg, "") == 0) {
258: if (optind >= ac - 1)
259: usage();
260: optarg = av[++optind];
261: }
262: } else {
263: if (av[optind][2])
264: usage();
265: optarg = NULL;
266: }
267: switch (opt) {
1.37 markus 268: case '4':
269: IPv4or6 = AF_INET;
270: break;
271:
272: case '6':
273: IPv4or6 = AF_INET6;
274: break;
275:
1.31 markus 276: case 'n':
277: stdin_null_flag = 1;
278: break;
279:
280: case 'f':
281: fork_after_authentication_flag = 1;
282: stdin_null_flag = 1;
283: break;
284:
285: case 'x':
286: options.forward_x11 = 0;
287: break;
288:
289: case 'X':
290: options.forward_x11 = 1;
291: break;
292:
293: case 'g':
294: options.gateway_ports = 1;
295: break;
296:
297: case 'P':
298: options.use_privileged_port = 0;
299: break;
300:
301: case 'a':
302: options.forward_agent = 0;
303: break;
1.9 dugsong 304: #ifdef AFS
1.31 markus 305: case 'k':
306: options.kerberos_tgt_passing = 0;
307: options.afs_token_passing = 0;
308: break;
1.1 deraadt 309: #endif
1.31 markus 310: case 'i':
311: if (stat(optarg, &st) < 0) {
312: fprintf(stderr, "Warning: Identity file %s does not exist.\n",
313: optarg);
314: break;
315: }
316: if (options.num_identity_files >= SSH_MAX_IDENTITY_FILES)
317: fatal("Too many identity files specified (max %d)",
318: SSH_MAX_IDENTITY_FILES);
319: options.identity_files[options.num_identity_files++] =
320: xstrdup(optarg);
321: break;
322:
323: case 't':
324: tty_flag = 1;
325: break;
326:
327: case 'v':
328: case 'V':
329: fprintf(stderr, "SSH Version %s, protocol version %d.%d.\n",
330: SSH_VERSION, PROTOCOL_MAJOR, PROTOCOL_MINOR);
1.45 ! markus 331: fprintf(stderr, "Compiled with SSL (0x%8.8lx).\n", SSLeay());
1.31 markus 332: if (opt == 'V')
333: exit(0);
334: debug_flag = 1;
335: options.log_level = SYSLOG_LEVEL_DEBUG;
336: break;
337:
338: case 'q':
339: options.log_level = SYSLOG_LEVEL_QUIET;
340: break;
341:
342: case 'e':
343: if (optarg[0] == '^' && optarg[2] == 0 &&
344: (unsigned char) optarg[1] >= 64 && (unsigned char) optarg[1] < 128)
345: options.escape_char = (unsigned char) optarg[1] & 31;
346: else if (strlen(optarg) == 1)
347: options.escape_char = (unsigned char) optarg[0];
348: else if (strcmp(optarg, "none") == 0)
349: options.escape_char = -2;
350: else {
351: fprintf(stderr, "Bad escape character '%s'.\n", optarg);
352: exit(1);
353: }
354: break;
355:
356: case 'c':
357: options.cipher = cipher_number(optarg);
358: if (options.cipher == -1) {
359: fprintf(stderr, "Unknown cipher type '%s'\n", optarg);
360: exit(1);
361: }
362: break;
363:
364: case 'p':
365: options.port = atoi(optarg);
366: break;
367:
368: case 'l':
369: options.user = optarg;
370: break;
371:
372: case 'R':
1.37 markus 373: if (sscanf(optarg, "%hu/%255[^/]/%hu", &fwd_port, buf,
374: &fwd_host_port) != 3 &&
375: sscanf(optarg, "%hu:%255[^:]:%hu", &fwd_port, buf,
376: &fwd_host_port) != 3) {
1.31 markus 377: fprintf(stderr, "Bad forwarding specification '%s'.\n", optarg);
378: usage();
379: /* NOTREACHED */
380: }
381: add_remote_forward(&options, fwd_port, buf, fwd_host_port);
382: break;
383:
384: case 'L':
1.37 markus 385: if (sscanf(optarg, "%hu/%255[^/]/%hu", &fwd_port, buf,
386: &fwd_host_port) != 3 &&
387: sscanf(optarg, "%hu:%255[^:]:%hu", &fwd_port, buf,
388: &fwd_host_port) != 3) {
1.31 markus 389: fprintf(stderr, "Bad forwarding specification '%s'.\n", optarg);
390: usage();
391: /* NOTREACHED */
392: }
393: add_local_forward(&options, fwd_port, buf, fwd_host_port);
394: break;
395:
396: case 'C':
397: options.compression = 1;
398: break;
399:
1.45 ! markus 400: case 'N':
! 401: no_shell_flag = 1;
! 402: no_tty_flag = 1;
! 403: break;
! 404:
! 405: case 'T':
! 406: no_tty_flag = 1;
! 407: break;
! 408:
1.31 markus 409: case 'o':
410: dummy = 1;
411: if (process_config_line(&options, host ? host : "", optarg,
412: "command-line", 0, &dummy) != 0)
413: exit(1);
414: break;
415:
416: default:
417: usage();
1.1 deraadt 418: }
1.31 markus 419: }
420:
421: /* Check that we got a host name. */
422: if (!host)
423: usage();
424:
425: /* check if RSA support exists */
426: if (rsa_alive() == 0) {
427: extern char *__progname;
428:
429: fprintf(stderr,
430: "%s: no RSA support in libssl and libcrypto. See ssl(8).\n",
431: __progname);
432: exit(1);
433: }
434: /* Initialize the command to execute on remote host. */
435: buffer_init(&command);
1.1 deraadt 436:
1.33 markus 437: /*
438: * Save the command to execute on the remote host in a buffer. There
439: * is no limit on the length of the command, except by the maximum
440: * packet size. Also sets the tty flag if there is no command.
441: */
1.31 markus 442: if (optind == ac) {
443: /* No command specified - execute shell on a tty. */
444: tty_flag = 1;
445: } else {
446: /* A command has been specified. Store it into the
447: buffer. */
448: for (i = optind; i < ac; i++) {
449: if (i > optind)
450: buffer_append(&command, " ", 1);
451: buffer_append(&command, av[i], strlen(av[i]));
452: }
453: }
454:
455: /* Cannot fork to background if no command. */
456: if (fork_after_authentication_flag && buffer_len(&command) == 0)
457: fatal("Cannot fork into background without a command to execute.");
458:
459: /* Allocate a tty by default if no command specified. */
460: if (buffer_len(&command) == 0)
461: tty_flag = 1;
462:
463: /* Do not allocate a tty if stdin is not a tty. */
464: if (!isatty(fileno(stdin))) {
465: if (tty_flag)
466: fprintf(stderr, "Pseudo-terminal will not be allocated because stdin is not a terminal.\n");
467: tty_flag = 0;
468: }
1.45 ! markus 469: /* force */
! 470: if (no_tty_flag)
! 471: tty_flag = 0;
! 472:
1.31 markus 473: /* Get user data. */
474: pw = getpwuid(original_real_uid);
475: if (!pw) {
476: fprintf(stderr, "You don't exist, go away!\n");
477: exit(1);
478: }
479: /* Take a copy of the returned structure. */
480: memset(&pwcopy, 0, sizeof(pwcopy));
481: pwcopy.pw_name = xstrdup(pw->pw_name);
482: pwcopy.pw_passwd = xstrdup(pw->pw_passwd);
483: pwcopy.pw_uid = pw->pw_uid;
484: pwcopy.pw_gid = pw->pw_gid;
485: pwcopy.pw_dir = xstrdup(pw->pw_dir);
486: pwcopy.pw_shell = xstrdup(pw->pw_shell);
487: pw = &pwcopy;
488:
489: /* Initialize "log" output. Since we are the client all output
490: actually goes to the terminal. */
491: log_init(av[0], options.log_level, SYSLOG_FACILITY_USER, 0);
492:
493: /* Read per-user configuration file. */
494: snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir, SSH_USER_CONFFILE);
495: read_config_file(buf, host, &options);
496:
497: /* Read systemwide configuration file. */
498: read_config_file(HOST_CONFIG_FILE, host, &options);
499:
500: /* Fill configuration defaults. */
501: fill_default_options(&options);
502:
503: /* reinit */
504: log_init(av[0], options.log_level, SYSLOG_FACILITY_USER, 0);
505:
506: if (options.user == NULL)
507: options.user = xstrdup(pw->pw_name);
508:
509: if (options.hostname != NULL)
510: host = options.hostname;
511:
512: /* Find canonic host name. */
513: if (strchr(host, '.') == 0) {
1.37 markus 514: struct addrinfo hints;
515: struct addrinfo *ai = NULL;
516: int errgai;
517: memset(&hints, 0, sizeof(hints));
1.40 markus 518: hints.ai_family = IPv4or6;
1.37 markus 519: hints.ai_flags = AI_CANONNAME;
1.39 markus 520: hints.ai_socktype = SOCK_STREAM;
1.37 markus 521: errgai = getaddrinfo(host, NULL, &hints, &ai);
522: if (errgai == 0) {
523: if (ai->ai_canonname != NULL)
524: host = xstrdup(ai->ai_canonname);
525: freeaddrinfo(ai);
1.31 markus 526: }
527: }
528: /* Disable rhosts authentication if not running as root. */
529: if (original_effective_uid != 0 || !options.use_privileged_port) {
530: options.rhosts_authentication = 0;
531: options.rhosts_rsa_authentication = 0;
532: }
1.33 markus 533: /*
534: * If using rsh has been selected, exec it now (without trying
535: * anything else). Note that we must release privileges first.
536: */
1.31 markus 537: if (options.use_rsh) {
1.33 markus 538: /*
539: * Restore our superuser privileges. This must be done
540: * before permanently setting the uid.
541: */
1.31 markus 542: restore_uid();
543:
544: /* Switch to the original uid permanently. */
545: permanently_set_uid(original_real_uid);
546:
547: /* Execute rsh. */
548: rsh_connect(host, options.user, &command);
549: fatal("rsh_connect returned");
550: }
551: /* Restore our superuser privileges. */
552: restore_uid();
553:
1.33 markus 554: /*
555: * Open a connection to the remote host. This needs root privileges
556: * if rhosts_{rsa_}authentication is enabled.
557: */
1.31 markus 558:
559: ok = ssh_connect(host, &hostaddr, options.port,
560: options.connection_attempts,
561: !options.rhosts_authentication &&
562: !options.rhosts_rsa_authentication,
563: original_real_uid,
564: options.proxy_command);
565:
1.33 markus 566: /*
567: * If we successfully made the connection, load the host private key
568: * in case we will need it later for combined rsa-rhosts
569: * authentication. This must be done before releasing extra
570: * privileges, because the file is only readable by root.
571: */
1.31 markus 572: if (ok) {
573: host_private_key = RSA_new();
574: if (load_private_key(HOST_KEY_FILE, "", host_private_key, NULL))
575: host_private_key_loaded = 1;
576: }
1.33 markus 577: /*
578: * Get rid of any extra privileges that we may have. We will no
579: * longer need them. Also, extra privileges could make it very hard
580: * to read identity files and other non-world-readable files from the
581: * user's home directory if it happens to be on a NFS volume where
582: * root is mapped to nobody.
583: */
584:
585: /*
586: * Note that some legacy systems need to postpone the following call
587: * to permanently_set_uid() until the private hostkey is destroyed
588: * with RSA_free(). Otherwise the calling user could ptrace() the
589: * process, read the private hostkey and impersonate the host.
590: * OpenBSD does not allow ptracing of setuid processes.
591: */
1.31 markus 592: permanently_set_uid(original_real_uid);
593:
1.33 markus 594: /*
595: * Now that we are back to our own permissions, create ~/.ssh
596: * directory if it doesn\'t already exist.
597: */
1.31 markus 598: snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir, SSH_USER_DIR);
599: if (stat(buf, &st) < 0)
600: if (mkdir(buf, 0755) < 0)
601: error("Could not create directory '%.200s'.", buf);
602:
603: /* Check if the connection failed, and try "rsh" if appropriate. */
604: if (!ok) {
605: if (options.port != 0)
1.35 markus 606: log("Secure connection to %.100s on port %hu refused%.100s.",
1.31 markus 607: host, options.port,
608: options.fallback_to_rsh ? "; reverting to insecure method" : "");
609: else
610: log("Secure connection to %.100s refused%.100s.", host,
611: options.fallback_to_rsh ? "; reverting to insecure method" : "");
612:
613: if (options.fallback_to_rsh) {
614: rsh_connect(host, options.user, &command);
615: fatal("rsh_connect returned");
616: }
617: exit(1);
618: }
619: /* Expand ~ in options.identity_files. */
620: for (i = 0; i < options.num_identity_files; i++)
621: options.identity_files[i] =
622: tilde_expand_filename(options.identity_files[i], original_real_uid);
623:
624: /* Expand ~ in known host file names. */
625: options.system_hostfile = tilde_expand_filename(options.system_hostfile,
626: original_real_uid);
627: options.user_hostfile = tilde_expand_filename(options.user_hostfile,
628: original_real_uid);
629:
630: /* Log into the remote system. This never returns if the login fails. */
631: ssh_login(host_private_key_loaded, host_private_key,
1.37 markus 632: host, (struct sockaddr *)&hostaddr, original_real_uid);
1.31 markus 633:
634: /* We no longer need the host private key. Clear it now. */
635: if (host_private_key_loaded)
636: RSA_free(host_private_key); /* Destroys contents safely */
637:
1.45 ! markus 638: exit_status = compat20 ? ssh_session2() : ssh_session();
! 639: packet_close();
! 640: return exit_status;
! 641: }
! 642:
! 643: int
! 644: ssh_session(void)
! 645: {
! 646: int type;
! 647: int i;
! 648: int plen;
! 649: int interactive = 0;
! 650: int have_tty = 0;
! 651: struct winsize ws;
! 652: int authfd;
! 653: char *cp;
! 654:
1.31 markus 655: /* Enable compression if requested. */
656: if (options.compression) {
657: debug("Requesting compression at level %d.", options.compression_level);
658:
659: if (options.compression_level < 1 || options.compression_level > 9)
660: fatal("Compression level must be from 1 (fast) to 9 (slow, best).");
661:
662: /* Send the request. */
663: packet_start(SSH_CMSG_REQUEST_COMPRESSION);
664: packet_put_int(options.compression_level);
665: packet_send();
666: packet_write_wait();
667: type = packet_read(&plen);
668: if (type == SSH_SMSG_SUCCESS)
669: packet_start_compression(options.compression_level);
670: else if (type == SSH_SMSG_FAILURE)
671: log("Warning: Remote host refused compression.");
672: else
673: packet_disconnect("Protocol error waiting for compression response.");
674: }
675: /* Allocate a pseudo tty if appropriate. */
676: if (tty_flag) {
677: debug("Requesting pty.");
678:
679: /* Start the packet. */
680: packet_start(SSH_CMSG_REQUEST_PTY);
681:
682: /* Store TERM in the packet. There is no limit on the
683: length of the string. */
684: cp = getenv("TERM");
685: if (!cp)
686: cp = "";
687: packet_put_string(cp, strlen(cp));
688:
689: /* Store window size in the packet. */
690: if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
691: memset(&ws, 0, sizeof(ws));
692: packet_put_int(ws.ws_row);
693: packet_put_int(ws.ws_col);
694: packet_put_int(ws.ws_xpixel);
695: packet_put_int(ws.ws_ypixel);
696:
697: /* Store tty modes in the packet. */
698: tty_make_modes(fileno(stdin));
699:
700: /* Send the packet, and wait for it to leave. */
701: packet_send();
702: packet_write_wait();
703:
704: /* Read response from the server. */
705: type = packet_read(&plen);
1.43 markus 706: if (type == SSH_SMSG_SUCCESS) {
1.31 markus 707: interactive = 1;
1.45 ! markus 708: have_tty = 1;
1.43 markus 709: } else if (type == SSH_SMSG_FAILURE)
1.31 markus 710: log("Warning: Remote host failed or refused to allocate a pseudo tty.");
711: else
712: packet_disconnect("Protocol error waiting for pty request response.");
713: }
714: /* Request X11 forwarding if enabled and DISPLAY is set. */
715: if (options.forward_x11 && getenv("DISPLAY") != NULL) {
716: char line[512], proto[512], data[512];
717: FILE *f;
718: int forwarded = 0, got_data = 0, i;
1.1 deraadt 719:
720: #ifdef XAUTH_PATH
1.31 markus 721: /* Try to get Xauthority information for the display. */
722: snprintf(line, sizeof line, "%.100s list %.200s 2>/dev/null",
723: XAUTH_PATH, getenv("DISPLAY"));
724: f = popen(line, "r");
725: if (f && fgets(line, sizeof(line), f) &&
726: sscanf(line, "%*s %s %s", proto, data) == 2)
727: got_data = 1;
728: if (f)
729: pclose(f);
1.1 deraadt 730: #endif /* XAUTH_PATH */
1.33 markus 731: /*
732: * If we didn't get authentication data, just make up some
733: * data. The forwarding code will check the validity of the
734: * response anyway, and substitute this data. The X11
735: * server, however, will ignore this fake data and use
736: * whatever authentication mechanisms it was using otherwise
737: * for the local connection.
738: */
1.31 markus 739: if (!got_data) {
740: u_int32_t rand = 0;
741:
742: strlcpy(proto, "MIT-MAGIC-COOKIE-1", sizeof proto);
743: for (i = 0; i < 16; i++) {
744: if (i % 4 == 0)
745: rand = arc4random();
746: snprintf(data + 2 * i, sizeof data - 2 * i, "%02x", rand & 0xff);
747: rand >>= 8;
748: }
749: }
1.33 markus 750: /*
751: * Got local authentication reasonable information. Request
752: * forwarding with authentication spoofing.
753: */
1.31 markus 754: debug("Requesting X11 forwarding with authentication spoofing.");
755: x11_request_forwarding_with_spoofing(proto, data);
756:
757: /* Read response from the server. */
758: type = packet_read(&plen);
759: if (type == SSH_SMSG_SUCCESS) {
760: forwarded = 1;
761: interactive = 1;
762: } else if (type == SSH_SMSG_FAILURE)
763: log("Warning: Remote host denied X11 forwarding.");
764: else
765: packet_disconnect("Protocol error waiting for X11 forwarding");
766: }
767: /* Tell the packet module whether this is an interactive session. */
768: packet_set_interactive(interactive, options.keepalives);
769:
770: /* Clear agent forwarding if we don\'t have an agent. */
771: authfd = ssh_get_authentication_socket();
772: if (authfd < 0)
773: options.forward_agent = 0;
774: else
775: ssh_close_authentication_socket(authfd);
776:
777: /* Request authentication agent forwarding if appropriate. */
778: if (options.forward_agent) {
779: debug("Requesting authentication agent forwarding.");
780: auth_request_forwarding();
781:
782: /* Read response from the server. */
783: type = packet_read(&plen);
784: packet_integrity_check(plen, 0, type);
785: if (type != SSH_SMSG_SUCCESS)
786: log("Warning: Remote host denied authentication agent forwarding.");
787: }
788: /* Initiate local TCP/IP port forwardings. */
789: for (i = 0; i < options.num_local_forwards; i++) {
790: debug("Connections to local port %d forwarded to remote address %.200s:%d",
791: options.local_forwards[i].port,
792: options.local_forwards[i].host,
793: options.local_forwards[i].host_port);
794: channel_request_local_forwarding(options.local_forwards[i].port,
795: options.local_forwards[i].host,
1.36 markus 796: options.local_forwards[i].host_port,
797: options.gateway_ports);
1.31 markus 798: }
799:
800: /* Initiate remote TCP/IP port forwardings. */
801: for (i = 0; i < options.num_remote_forwards; i++) {
802: debug("Connections to remote port %d forwarded to local address %.200s:%d",
803: options.remote_forwards[i].port,
804: options.remote_forwards[i].host,
805: options.remote_forwards[i].host_port);
806: channel_request_remote_forwarding(options.remote_forwards[i].port,
807: options.remote_forwards[i].host,
808: options.remote_forwards[i].host_port);
809: }
1.34 markus 810:
811: /* If requested, let ssh continue in the background. */
812: if (fork_after_authentication_flag)
813: if (daemon(1, 1) < 0)
814: fatal("daemon() failed: %.200s", strerror(errno));
1.31 markus 815:
1.33 markus 816: /*
817: * If a command was specified on the command line, execute the
818: * command now. Otherwise request the server to start a shell.
819: */
1.31 markus 820: if (buffer_len(&command) > 0) {
821: int len = buffer_len(&command);
822: if (len > 900)
823: len = 900;
824: debug("Sending command: %.*s", len, buffer_ptr(&command));
825: packet_start(SSH_CMSG_EXEC_CMD);
826: packet_put_string(buffer_ptr(&command), buffer_len(&command));
827: packet_send();
828: packet_write_wait();
829: } else {
830: debug("Requesting shell.");
831: packet_start(SSH_CMSG_EXEC_SHELL);
832: packet_send();
833: packet_write_wait();
834: }
835:
836: /* Enter the interactive session. */
1.45 ! markus 837: return client_loop(have_tty, tty_flag ? options.escape_char : -1);
! 838: }
! 839:
! 840: void
! 841: init_local_fwd(void)
! 842: {
! 843: int i;
! 844: /* Initiate local TCP/IP port forwardings. */
! 845: for (i = 0; i < options.num_local_forwards; i++) {
! 846: debug("Connections to local port %d forwarded to remote address %.200s:%d",
! 847: options.local_forwards[i].port,
! 848: options.local_forwards[i].host,
! 849: options.local_forwards[i].host_port);
! 850: channel_request_local_forwarding(options.local_forwards[i].port,
! 851: options.local_forwards[i].host,
! 852: options.local_forwards[i].host_port,
! 853: options.gateway_ports);
! 854: }
! 855: }
! 856:
! 857: extern void client_set_session_ident(int id);
! 858:
! 859: void
! 860: client_init(int id, void *arg)
! 861: {
! 862: int len;
! 863: debug("client_init id %d arg %d", id, (int)arg);
1.31 markus 864:
1.45 ! markus 865: if (no_shell_flag)
! 866: goto done;
! 867:
! 868: if (tty_flag) {
! 869: struct winsize ws;
! 870: char *cp;
! 871: cp = getenv("TERM");
! 872: if (!cp)
! 873: cp = "";
! 874: /* Store window size in the packet. */
! 875: if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
! 876: memset(&ws, 0, sizeof(ws));
! 877:
! 878: channel_request_start(id, "pty-req", 0);
! 879: packet_put_cstring(cp);
! 880: packet_put_int(ws.ws_col);
! 881: packet_put_int(ws.ws_row);
! 882: packet_put_int(ws.ws_xpixel);
! 883: packet_put_int(ws.ws_ypixel);
! 884: packet_put_cstring(""); /* XXX: encode terminal modes */
! 885: packet_send();
! 886: /* XXX wait for reply */
! 887: }
! 888: len = buffer_len(&command);
! 889: if (len > 0) {
! 890: if (len > 900)
! 891: len = 900;
! 892: debug("Sending command: %.*s", len, buffer_ptr(&command));
! 893: channel_request_start(id, "exec", 0);
! 894: packet_put_string(buffer_ptr(&command), len);
! 895: packet_send();
! 896: } else {
! 897: channel_request(id, "shell", 0);
! 898: }
! 899: /* channel_callback(id, SSH2_MSG_OPEN_CONFIGMATION, client_init, 0); */
! 900: done:
! 901: /* register different callback, etc. XXX */
! 902: client_set_session_ident(id);
! 903: }
! 904:
! 905: int
! 906: ssh_session2(void)
! 907: {
! 908: int window, packetmax, id;
! 909: int in = dup(STDIN_FILENO);
! 910: int out = dup(STDOUT_FILENO);
! 911: int err = dup(STDERR_FILENO);
! 912:
! 913: if (in < 0 || out < 0 || err < 0)
! 914: fatal("dump in/out/err failed");
! 915:
! 916: /* should be pre-session */
! 917: init_local_fwd();
! 918:
! 919: window = 32*1024;
! 920: if (tty_flag) {
! 921: packetmax = window/8;
! 922: } else {
! 923: window *= 2;
! 924: packetmax = window/2;
! 925: }
! 926:
! 927: id = channel_new(
! 928: "session", SSH_CHANNEL_OPENING, in, out, err,
! 929: window, packetmax, CHAN_EXTENDED_WRITE, xstrdup("client-session"));
! 930:
! 931:
! 932: channel_open(id);
! 933: channel_register_callback(id, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, client_init, (void *)0);
1.31 markus 934:
1.45 ! markus 935: return client_loop(tty_flag, tty_flag ? options.escape_char : -1);
1.1 deraadt 936: }
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