Annotation of src/usr.bin/ssh/ssh.c, Revision 1.46
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"
1.46 ! markus 14: RCSID("$Id: ssh.c,v 1.45 2000/04/04 15:19:42 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:
1.46 ! markus 35: /* Flag indicating whether a tty should be allocated */
1.1 deraadt 36: int tty_flag = 0;
37:
1.45 markus 38: /* don't exec a shell */
39: int no_shell_flag = 0;
40: int no_tty_flag = 0;
41:
1.33 markus 42: /*
43: * Flag indicating that nothing should be read from stdin. This can be set
44: * on the command line.
45: */
1.1 deraadt 46: int stdin_null_flag = 0;
47:
1.33 markus 48: /*
49: * Flag indicating that ssh should fork after authentication. This is useful
50: * so that the pasphrase can be entered manually, and then ssh goes to the
51: * background.
52: */
1.1 deraadt 53: int fork_after_authentication_flag = 0;
54:
1.33 markus 55: /*
56: * General data structure for command line options and options configurable
57: * in configuration files. See readconf.h.
58: */
1.1 deraadt 59: Options options;
60:
1.33 markus 61: /*
62: * Name of the host we are connecting to. This is the name given on the
63: * command line, or the HostName specified for the user-supplied name in a
64: * configuration file.
65: */
1.1 deraadt 66: char *host;
67:
1.22 provos 68: /* socket address the host resolves to */
1.37 markus 69: struct sockaddr_storage hostaddr;
1.22 provos 70:
1.33 markus 71: /*
72: * Flag to indicate that we have received a window change signal which has
73: * not yet been processed. This will cause a message indicating the new
74: * window size to be sent to the server a little later. This is volatile
75: * because this is updated in a signal handler.
76: */
1.1 deraadt 77: volatile int received_window_change_signal = 0;
78:
79: /* Value of argv[0] (set in the main program). */
80: char *av0;
81:
82: /* Flag indicating whether we have a valid host private key loaded. */
83: int host_private_key_loaded = 0;
84:
85: /* Host private key. */
1.2 provos 86: RSA *host_private_key = NULL;
1.1 deraadt 87:
1.10 dugsong 88: /* Original real UID. */
89: uid_t original_real_uid;
1.1 deraadt 90:
1.45 markus 91: /* command to be executed */
92: Buffer command;
93:
1.1 deraadt 94: /* Prints a help message to the user. This function never returns. */
95:
1.2 provos 96: void
97: usage()
1.1 deraadt 98: {
1.31 markus 99: fprintf(stderr, "Usage: %s [options] host [command]\n", av0);
100: fprintf(stderr, "Options:\n");
101: fprintf(stderr, " -l user Log in using this user name.\n");
102: fprintf(stderr, " -n Redirect input from /dev/null.\n");
103: fprintf(stderr, " -a Disable authentication agent forwarding.\n");
1.9 dugsong 104: #ifdef AFS
1.31 markus 105: fprintf(stderr, " -k Disable Kerberos ticket and AFS token forwarding.\n");
106: #endif /* AFS */
107: fprintf(stderr, " -x Disable X11 connection forwarding.\n");
108: fprintf(stderr, " -i file Identity for RSA authentication (default: ~/.ssh/identity).\n");
109: fprintf(stderr, " -t Tty; allocate a tty even if command is given.\n");
1.45 markus 110: fprintf(stderr, " -T Do not allocate a tty.\n");
1.31 markus 111: fprintf(stderr, " -v Verbose; display verbose debugging messages.\n");
112: fprintf(stderr, " -V Display version number only.\n");
113: fprintf(stderr, " -P Don't allocate a privileged port.\n");
114: fprintf(stderr, " -q Quiet; don't display any warning messages.\n");
115: fprintf(stderr, " -f Fork into background after authentication.\n");
116: fprintf(stderr, " -e char Set escape character; ``none'' = disable (default: ~).\n");
117:
118: fprintf(stderr, " -c cipher Select encryption algorithm: "
119: "``3des'', "
120: "``blowfish''\n");
121: fprintf(stderr, " -p port Connect to this port. Server must be on the same port.\n");
122: fprintf(stderr, " -L listen-port:host:port Forward local port to remote address\n");
123: fprintf(stderr, " -R listen-port:host:port Forward remote port to local address\n");
124: fprintf(stderr, " These cause %s to listen for connections on a port, and\n", av0);
125: fprintf(stderr, " forward them to the other side by connecting to host:port.\n");
126: fprintf(stderr, " -C Enable compression.\n");
1.45 markus 127: fprintf(stderr, " -N Do not execute a shell or command.\n");
1.31 markus 128: fprintf(stderr, " -g Allow remote hosts to connect to forwarded ports.\n");
1.37 markus 129: fprintf(stderr, " -4 Use IPv4 only.\n");
130: fprintf(stderr, " -6 Use IPv6 only.\n");
1.31 markus 131: fprintf(stderr, " -o 'option' Process the option as if it was read from a configuration file.\n");
132: exit(1);
1.1 deraadt 133: }
134:
1.32 deraadt 135: /*
136: * Connects to the given host using rsh (or prints an error message and exits
137: * if rsh is not available). This function never returns.
138: */
1.2 provos 139: void
1.31 markus 140: rsh_connect(char *host, char *user, Buffer * command)
1.1 deraadt 141: {
1.31 markus 142: char *args[10];
143: int i;
144:
145: log("Using rsh. WARNING: Connection will not be encrypted.");
146: /* Build argument list for rsh. */
147: i = 0;
148: args[i++] = _PATH_RSH;
149: /* host may have to come after user on some systems */
150: args[i++] = host;
151: if (user) {
152: args[i++] = "-l";
153: args[i++] = user;
154: }
155: if (buffer_len(command) > 0) {
156: buffer_append(command, "\0", 1);
157: args[i++] = buffer_ptr(command);
158: }
159: args[i++] = NULL;
160: if (debug_flag) {
161: for (i = 0; args[i]; i++) {
162: if (i != 0)
163: fprintf(stderr, " ");
164: fprintf(stderr, "%s", args[i]);
165: }
166: fprintf(stderr, "\n");
167: }
168: execv(_PATH_RSH, args);
169: perror(_PATH_RSH);
170: exit(1);
1.1 deraadt 171: }
172:
1.45 markus 173: int ssh_session(void);
174: int ssh_session2(void);
175:
1.32 deraadt 176: /*
177: * Main program for the ssh client.
178: */
1.2 provos 179: int
180: main(int ac, char **av)
1.1 deraadt 181: {
1.45 markus 182: int i, opt, optind, exit_status, ok;
1.35 markus 183: u_short fwd_port, fwd_host_port;
1.31 markus 184: char *optarg, *cp, buf[256];
185: struct stat st;
186: struct passwd *pw, pwcopy;
1.45 markus 187: int dummy;
1.31 markus 188: uid_t original_effective_uid;
189:
1.33 markus 190: /*
191: * Save the original real uid. It will be needed later (uid-swapping
192: * may clobber the real uid).
193: */
1.31 markus 194: original_real_uid = getuid();
195: original_effective_uid = geteuid();
196:
197: /* If we are installed setuid root be careful to not drop core. */
198: if (original_real_uid != original_effective_uid) {
199: struct rlimit rlim;
200: rlim.rlim_cur = rlim.rlim_max = 0;
201: if (setrlimit(RLIMIT_CORE, &rlim) < 0)
202: fatal("setrlimit failed: %.100s", strerror(errno));
1.1 deraadt 203: }
1.33 markus 204: /*
205: * Use uid-swapping to give up root privileges for the duration of
206: * option processing. We will re-instantiate the rights when we are
207: * ready to create the privileged port, and will permanently drop
208: * them when the port has been created (actually, when the connection
209: * has been made, as we may need to create the port several times).
210: */
1.31 markus 211: temporarily_use_uid(original_real_uid);
212:
1.33 markus 213: /*
214: * Set our umask to something reasonable, as some files are created
215: * with the default umask. This will make them world-readable but
216: * writable only by the owner, which is ok for all files for which we
217: * don't set the modes explicitly.
218: */
1.31 markus 219: umask(022);
220:
221: /* Save our own name. */
222: av0 = av[0];
223:
224: /* Initialize option structure to indicate that no values have been set. */
225: initialize_options(&options);
226:
227: /* Parse command-line arguments. */
228: host = NULL;
229:
230: /* If program name is not one of the standard names, use it as host name. */
231: if (strchr(av0, '/'))
232: cp = strrchr(av0, '/') + 1;
233: else
234: cp = av0;
235: if (strcmp(cp, "rsh") != 0 && strcmp(cp, "ssh") != 0 &&
236: strcmp(cp, "rlogin") != 0 && strcmp(cp, "slogin") != 0)
237: host = cp;
238:
239: for (optind = 1; optind < ac; optind++) {
240: if (av[optind][0] != '-') {
241: if (host)
242: break;
243: if ((cp = strchr(av[optind], '@'))) {
1.38 markus 244: if(cp == av[optind])
245: usage();
1.31 markus 246: options.user = av[optind];
247: *cp = '\0';
248: host = ++cp;
249: } else
250: host = av[optind];
251: continue;
252: }
253: opt = av[optind][1];
254: if (!opt)
255: usage();
256: if (strchr("eilcpLRo", opt)) { /* options with arguments */
257: optarg = av[optind] + 2;
258: if (strcmp(optarg, "") == 0) {
259: if (optind >= ac - 1)
260: usage();
261: optarg = av[++optind];
262: }
263: } else {
264: if (av[optind][2])
265: usage();
266: optarg = NULL;
267: }
268: switch (opt) {
1.37 markus 269: case '4':
270: IPv4or6 = AF_INET;
271: break;
272:
273: case '6':
274: IPv4or6 = AF_INET6;
275: break;
276:
1.31 markus 277: case 'n':
278: stdin_null_flag = 1;
279: break;
280:
281: case 'f':
282: fork_after_authentication_flag = 1;
283: stdin_null_flag = 1;
284: break;
285:
286: case 'x':
287: options.forward_x11 = 0;
288: break;
289:
290: case 'X':
291: options.forward_x11 = 1;
292: break;
293:
294: case 'g':
295: options.gateway_ports = 1;
296: break;
297:
298: case 'P':
299: options.use_privileged_port = 0;
300: break;
301:
302: case 'a':
303: options.forward_agent = 0;
304: break;
1.9 dugsong 305: #ifdef AFS
1.31 markus 306: case 'k':
307: options.kerberos_tgt_passing = 0;
308: options.afs_token_passing = 0;
309: break;
1.1 deraadt 310: #endif
1.31 markus 311: case 'i':
312: if (stat(optarg, &st) < 0) {
313: fprintf(stderr, "Warning: Identity file %s does not exist.\n",
314: optarg);
315: break;
316: }
317: if (options.num_identity_files >= SSH_MAX_IDENTITY_FILES)
318: fatal("Too many identity files specified (max %d)",
319: SSH_MAX_IDENTITY_FILES);
320: options.identity_files[options.num_identity_files++] =
321: xstrdup(optarg);
322: break;
323:
324: case 't':
325: tty_flag = 1;
326: break;
327:
328: case 'v':
329: case 'V':
1.46 ! markus 330: fprintf(stderr, "SSH Version %s, protocol versions %d.%d/%d.%d.\n",
! 331: SSH_VERSION,
! 332: PROTOCOL_MAJOR_1, PROTOCOL_MINOR_1,
! 333: PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2);
1.45 markus 334: fprintf(stderr, "Compiled with SSL (0x%8.8lx).\n", SSLeay());
1.31 markus 335: if (opt == 'V')
336: exit(0);
337: debug_flag = 1;
338: options.log_level = SYSLOG_LEVEL_DEBUG;
339: break;
340:
341: case 'q':
342: options.log_level = SYSLOG_LEVEL_QUIET;
343: break;
344:
345: case 'e':
346: if (optarg[0] == '^' && optarg[2] == 0 &&
347: (unsigned char) optarg[1] >= 64 && (unsigned char) optarg[1] < 128)
348: options.escape_char = (unsigned char) optarg[1] & 31;
349: else if (strlen(optarg) == 1)
350: options.escape_char = (unsigned char) optarg[0];
351: else if (strcmp(optarg, "none") == 0)
352: options.escape_char = -2;
353: else {
354: fprintf(stderr, "Bad escape character '%s'.\n", optarg);
355: exit(1);
356: }
357: break;
358:
359: case 'c':
360: options.cipher = cipher_number(optarg);
361: if (options.cipher == -1) {
362: fprintf(stderr, "Unknown cipher type '%s'\n", optarg);
363: exit(1);
364: }
365: break;
366:
367: case 'p':
368: options.port = atoi(optarg);
369: break;
370:
371: case 'l':
372: options.user = optarg;
373: break;
374:
375: case 'R':
1.37 markus 376: if (sscanf(optarg, "%hu/%255[^/]/%hu", &fwd_port, buf,
377: &fwd_host_port) != 3 &&
378: sscanf(optarg, "%hu:%255[^:]:%hu", &fwd_port, buf,
379: &fwd_host_port) != 3) {
1.31 markus 380: fprintf(stderr, "Bad forwarding specification '%s'.\n", optarg);
381: usage();
382: /* NOTREACHED */
383: }
384: add_remote_forward(&options, fwd_port, buf, fwd_host_port);
385: break;
386:
387: case 'L':
1.37 markus 388: if (sscanf(optarg, "%hu/%255[^/]/%hu", &fwd_port, buf,
389: &fwd_host_port) != 3 &&
390: sscanf(optarg, "%hu:%255[^:]:%hu", &fwd_port, buf,
391: &fwd_host_port) != 3) {
1.31 markus 392: fprintf(stderr, "Bad forwarding specification '%s'.\n", optarg);
393: usage();
394: /* NOTREACHED */
395: }
396: add_local_forward(&options, fwd_port, buf, fwd_host_port);
397: break;
398:
399: case 'C':
400: options.compression = 1;
401: break;
402:
1.45 markus 403: case 'N':
404: no_shell_flag = 1;
405: no_tty_flag = 1;
406: break;
407:
408: case 'T':
409: no_tty_flag = 1;
410: break;
411:
1.31 markus 412: case 'o':
413: dummy = 1;
414: if (process_config_line(&options, host ? host : "", optarg,
415: "command-line", 0, &dummy) != 0)
416: exit(1);
417: break;
418:
419: default:
420: usage();
1.1 deraadt 421: }
1.31 markus 422: }
423:
424: /* Check that we got a host name. */
425: if (!host)
426: usage();
427:
428: /* check if RSA support exists */
429: if (rsa_alive() == 0) {
430: extern char *__progname;
431:
432: fprintf(stderr,
433: "%s: no RSA support in libssl and libcrypto. See ssl(8).\n",
434: __progname);
435: exit(1);
436: }
437: /* Initialize the command to execute on remote host. */
438: buffer_init(&command);
1.1 deraadt 439:
1.33 markus 440: /*
441: * Save the command to execute on the remote host in a buffer. There
442: * is no limit on the length of the command, except by the maximum
443: * packet size. Also sets the tty flag if there is no command.
444: */
1.31 markus 445: if (optind == ac) {
446: /* No command specified - execute shell on a tty. */
447: tty_flag = 1;
448: } else {
449: /* A command has been specified. Store it into the
450: buffer. */
451: for (i = optind; i < ac; i++) {
452: if (i > optind)
453: buffer_append(&command, " ", 1);
454: buffer_append(&command, av[i], strlen(av[i]));
455: }
456: }
457:
458: /* Cannot fork to background if no command. */
459: if (fork_after_authentication_flag && buffer_len(&command) == 0)
460: fatal("Cannot fork into background without a command to execute.");
461:
462: /* Allocate a tty by default if no command specified. */
463: if (buffer_len(&command) == 0)
464: tty_flag = 1;
465:
466: /* Do not allocate a tty if stdin is not a tty. */
467: if (!isatty(fileno(stdin))) {
468: if (tty_flag)
469: fprintf(stderr, "Pseudo-terminal will not be allocated because stdin is not a terminal.\n");
470: tty_flag = 0;
471: }
1.45 markus 472: /* force */
473: if (no_tty_flag)
474: tty_flag = 0;
475:
1.31 markus 476: /* Get user data. */
477: pw = getpwuid(original_real_uid);
478: if (!pw) {
479: fprintf(stderr, "You don't exist, go away!\n");
480: exit(1);
481: }
482: /* Take a copy of the returned structure. */
483: memset(&pwcopy, 0, sizeof(pwcopy));
484: pwcopy.pw_name = xstrdup(pw->pw_name);
485: pwcopy.pw_passwd = xstrdup(pw->pw_passwd);
486: pwcopy.pw_uid = pw->pw_uid;
487: pwcopy.pw_gid = pw->pw_gid;
488: pwcopy.pw_dir = xstrdup(pw->pw_dir);
489: pwcopy.pw_shell = xstrdup(pw->pw_shell);
490: pw = &pwcopy;
491:
492: /* Initialize "log" output. Since we are the client all output
493: actually goes to the terminal. */
494: log_init(av[0], options.log_level, SYSLOG_FACILITY_USER, 0);
495:
496: /* Read per-user configuration file. */
497: snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir, SSH_USER_CONFFILE);
498: read_config_file(buf, host, &options);
499:
500: /* Read systemwide configuration file. */
501: read_config_file(HOST_CONFIG_FILE, host, &options);
502:
503: /* Fill configuration defaults. */
504: fill_default_options(&options);
505:
506: /* reinit */
507: log_init(av[0], options.log_level, SYSLOG_FACILITY_USER, 0);
508:
509: if (options.user == NULL)
510: options.user = xstrdup(pw->pw_name);
511:
512: if (options.hostname != NULL)
513: host = options.hostname;
514:
515: /* Find canonic host name. */
516: if (strchr(host, '.') == 0) {
1.37 markus 517: struct addrinfo hints;
518: struct addrinfo *ai = NULL;
519: int errgai;
520: memset(&hints, 0, sizeof(hints));
1.40 markus 521: hints.ai_family = IPv4or6;
1.37 markus 522: hints.ai_flags = AI_CANONNAME;
1.39 markus 523: hints.ai_socktype = SOCK_STREAM;
1.37 markus 524: errgai = getaddrinfo(host, NULL, &hints, &ai);
525: if (errgai == 0) {
526: if (ai->ai_canonname != NULL)
527: host = xstrdup(ai->ai_canonname);
528: freeaddrinfo(ai);
1.31 markus 529: }
530: }
531: /* Disable rhosts authentication if not running as root. */
532: if (original_effective_uid != 0 || !options.use_privileged_port) {
533: options.rhosts_authentication = 0;
534: options.rhosts_rsa_authentication = 0;
535: }
1.33 markus 536: /*
537: * If using rsh has been selected, exec it now (without trying
538: * anything else). Note that we must release privileges first.
539: */
1.31 markus 540: if (options.use_rsh) {
1.33 markus 541: /*
542: * Restore our superuser privileges. This must be done
543: * before permanently setting the uid.
544: */
1.31 markus 545: restore_uid();
546:
547: /* Switch to the original uid permanently. */
548: permanently_set_uid(original_real_uid);
549:
550: /* Execute rsh. */
551: rsh_connect(host, options.user, &command);
552: fatal("rsh_connect returned");
553: }
554: /* Restore our superuser privileges. */
555: restore_uid();
556:
1.33 markus 557: /*
558: * Open a connection to the remote host. This needs root privileges
559: * if rhosts_{rsa_}authentication is enabled.
560: */
1.31 markus 561:
562: ok = ssh_connect(host, &hostaddr, options.port,
563: options.connection_attempts,
564: !options.rhosts_authentication &&
565: !options.rhosts_rsa_authentication,
566: original_real_uid,
567: options.proxy_command);
568:
1.33 markus 569: /*
570: * If we successfully made the connection, load the host private key
571: * in case we will need it later for combined rsa-rhosts
572: * authentication. This must be done before releasing extra
573: * privileges, because the file is only readable by root.
574: */
1.31 markus 575: if (ok) {
576: host_private_key = RSA_new();
577: if (load_private_key(HOST_KEY_FILE, "", host_private_key, NULL))
578: host_private_key_loaded = 1;
579: }
1.33 markus 580: /*
581: * Get rid of any extra privileges that we may have. We will no
582: * longer need them. Also, extra privileges could make it very hard
583: * to read identity files and other non-world-readable files from the
584: * user's home directory if it happens to be on a NFS volume where
585: * root is mapped to nobody.
586: */
587:
588: /*
589: * Note that some legacy systems need to postpone the following call
590: * to permanently_set_uid() until the private hostkey is destroyed
591: * with RSA_free(). Otherwise the calling user could ptrace() the
592: * process, read the private hostkey and impersonate the host.
593: * OpenBSD does not allow ptracing of setuid processes.
594: */
1.31 markus 595: permanently_set_uid(original_real_uid);
596:
1.33 markus 597: /*
598: * Now that we are back to our own permissions, create ~/.ssh
599: * directory if it doesn\'t already exist.
600: */
1.31 markus 601: snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir, SSH_USER_DIR);
602: if (stat(buf, &st) < 0)
603: if (mkdir(buf, 0755) < 0)
604: error("Could not create directory '%.200s'.", buf);
605:
606: /* Check if the connection failed, and try "rsh" if appropriate. */
607: if (!ok) {
608: if (options.port != 0)
1.35 markus 609: log("Secure connection to %.100s on port %hu refused%.100s.",
1.31 markus 610: host, options.port,
611: options.fallback_to_rsh ? "; reverting to insecure method" : "");
612: else
613: log("Secure connection to %.100s refused%.100s.", host,
614: options.fallback_to_rsh ? "; reverting to insecure method" : "");
615:
616: if (options.fallback_to_rsh) {
617: rsh_connect(host, options.user, &command);
618: fatal("rsh_connect returned");
619: }
620: exit(1);
621: }
622: /* Expand ~ in options.identity_files. */
623: for (i = 0; i < options.num_identity_files; i++)
624: options.identity_files[i] =
625: tilde_expand_filename(options.identity_files[i], original_real_uid);
626:
627: /* Expand ~ in known host file names. */
628: options.system_hostfile = tilde_expand_filename(options.system_hostfile,
629: original_real_uid);
630: options.user_hostfile = tilde_expand_filename(options.user_hostfile,
631: original_real_uid);
632:
633: /* Log into the remote system. This never returns if the login fails. */
634: ssh_login(host_private_key_loaded, host_private_key,
1.37 markus 635: host, (struct sockaddr *)&hostaddr, original_real_uid);
1.31 markus 636:
637: /* We no longer need the host private key. Clear it now. */
638: if (host_private_key_loaded)
639: RSA_free(host_private_key); /* Destroys contents safely */
640:
1.45 markus 641: exit_status = compat20 ? ssh_session2() : ssh_session();
642: packet_close();
643: return exit_status;
644: }
645:
646: int
647: ssh_session(void)
648: {
649: int type;
650: int i;
651: int plen;
652: int interactive = 0;
653: int have_tty = 0;
654: struct winsize ws;
655: int authfd;
656: char *cp;
657:
1.31 markus 658: /* Enable compression if requested. */
659: if (options.compression) {
660: debug("Requesting compression at level %d.", options.compression_level);
661:
662: if (options.compression_level < 1 || options.compression_level > 9)
663: fatal("Compression level must be from 1 (fast) to 9 (slow, best).");
664:
665: /* Send the request. */
666: packet_start(SSH_CMSG_REQUEST_COMPRESSION);
667: packet_put_int(options.compression_level);
668: packet_send();
669: packet_write_wait();
670: type = packet_read(&plen);
671: if (type == SSH_SMSG_SUCCESS)
672: packet_start_compression(options.compression_level);
673: else if (type == SSH_SMSG_FAILURE)
674: log("Warning: Remote host refused compression.");
675: else
676: packet_disconnect("Protocol error waiting for compression response.");
677: }
678: /* Allocate a pseudo tty if appropriate. */
679: if (tty_flag) {
680: debug("Requesting pty.");
681:
682: /* Start the packet. */
683: packet_start(SSH_CMSG_REQUEST_PTY);
684:
685: /* Store TERM in the packet. There is no limit on the
686: length of the string. */
687: cp = getenv("TERM");
688: if (!cp)
689: cp = "";
690: packet_put_string(cp, strlen(cp));
691:
692: /* Store window size in the packet. */
693: if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
694: memset(&ws, 0, sizeof(ws));
695: packet_put_int(ws.ws_row);
696: packet_put_int(ws.ws_col);
697: packet_put_int(ws.ws_xpixel);
698: packet_put_int(ws.ws_ypixel);
699:
700: /* Store tty modes in the packet. */
701: tty_make_modes(fileno(stdin));
702:
703: /* Send the packet, and wait for it to leave. */
704: packet_send();
705: packet_write_wait();
706:
707: /* Read response from the server. */
708: type = packet_read(&plen);
1.43 markus 709: if (type == SSH_SMSG_SUCCESS) {
1.31 markus 710: interactive = 1;
1.45 markus 711: have_tty = 1;
1.43 markus 712: } else if (type == SSH_SMSG_FAILURE)
1.31 markus 713: log("Warning: Remote host failed or refused to allocate a pseudo tty.");
714: else
715: packet_disconnect("Protocol error waiting for pty request response.");
716: }
717: /* Request X11 forwarding if enabled and DISPLAY is set. */
718: if (options.forward_x11 && getenv("DISPLAY") != NULL) {
719: char line[512], proto[512], data[512];
720: FILE *f;
721: int forwarded = 0, got_data = 0, i;
1.1 deraadt 722:
723: #ifdef XAUTH_PATH
1.31 markus 724: /* Try to get Xauthority information for the display. */
725: snprintf(line, sizeof line, "%.100s list %.200s 2>/dev/null",
726: XAUTH_PATH, getenv("DISPLAY"));
727: f = popen(line, "r");
728: if (f && fgets(line, sizeof(line), f) &&
729: sscanf(line, "%*s %s %s", proto, data) == 2)
730: got_data = 1;
731: if (f)
732: pclose(f);
1.1 deraadt 733: #endif /* XAUTH_PATH */
1.33 markus 734: /*
735: * If we didn't get authentication data, just make up some
736: * data. The forwarding code will check the validity of the
737: * response anyway, and substitute this data. The X11
738: * server, however, will ignore this fake data and use
739: * whatever authentication mechanisms it was using otherwise
740: * for the local connection.
741: */
1.31 markus 742: if (!got_data) {
743: u_int32_t rand = 0;
744:
745: strlcpy(proto, "MIT-MAGIC-COOKIE-1", sizeof proto);
746: for (i = 0; i < 16; i++) {
747: if (i % 4 == 0)
748: rand = arc4random();
749: snprintf(data + 2 * i, sizeof data - 2 * i, "%02x", rand & 0xff);
750: rand >>= 8;
751: }
752: }
1.33 markus 753: /*
754: * Got local authentication reasonable information. Request
755: * forwarding with authentication spoofing.
756: */
1.31 markus 757: debug("Requesting X11 forwarding with authentication spoofing.");
758: x11_request_forwarding_with_spoofing(proto, data);
759:
760: /* Read response from the server. */
761: type = packet_read(&plen);
762: if (type == SSH_SMSG_SUCCESS) {
763: forwarded = 1;
764: interactive = 1;
765: } else if (type == SSH_SMSG_FAILURE)
766: log("Warning: Remote host denied X11 forwarding.");
767: else
768: packet_disconnect("Protocol error waiting for X11 forwarding");
769: }
770: /* Tell the packet module whether this is an interactive session. */
771: packet_set_interactive(interactive, options.keepalives);
772:
773: /* Clear agent forwarding if we don\'t have an agent. */
774: authfd = ssh_get_authentication_socket();
775: if (authfd < 0)
776: options.forward_agent = 0;
777: else
778: ssh_close_authentication_socket(authfd);
779:
780: /* Request authentication agent forwarding if appropriate. */
781: if (options.forward_agent) {
782: debug("Requesting authentication agent forwarding.");
783: auth_request_forwarding();
784:
785: /* Read response from the server. */
786: type = packet_read(&plen);
787: packet_integrity_check(plen, 0, type);
788: if (type != SSH_SMSG_SUCCESS)
789: log("Warning: Remote host denied authentication agent forwarding.");
790: }
791: /* Initiate local TCP/IP port forwardings. */
792: for (i = 0; i < options.num_local_forwards; i++) {
793: debug("Connections to local port %d forwarded to remote address %.200s:%d",
794: options.local_forwards[i].port,
795: options.local_forwards[i].host,
796: options.local_forwards[i].host_port);
797: channel_request_local_forwarding(options.local_forwards[i].port,
798: options.local_forwards[i].host,
1.36 markus 799: options.local_forwards[i].host_port,
800: options.gateway_ports);
1.31 markus 801: }
802:
803: /* Initiate remote TCP/IP port forwardings. */
804: for (i = 0; i < options.num_remote_forwards; i++) {
805: debug("Connections to remote port %d forwarded to local address %.200s:%d",
806: options.remote_forwards[i].port,
807: options.remote_forwards[i].host,
808: options.remote_forwards[i].host_port);
809: channel_request_remote_forwarding(options.remote_forwards[i].port,
810: options.remote_forwards[i].host,
811: options.remote_forwards[i].host_port);
812: }
1.34 markus 813:
814: /* If requested, let ssh continue in the background. */
815: if (fork_after_authentication_flag)
816: if (daemon(1, 1) < 0)
817: fatal("daemon() failed: %.200s", strerror(errno));
1.31 markus 818:
1.33 markus 819: /*
820: * If a command was specified on the command line, execute the
821: * command now. Otherwise request the server to start a shell.
822: */
1.31 markus 823: if (buffer_len(&command) > 0) {
824: int len = buffer_len(&command);
825: if (len > 900)
826: len = 900;
827: debug("Sending command: %.*s", len, buffer_ptr(&command));
828: packet_start(SSH_CMSG_EXEC_CMD);
829: packet_put_string(buffer_ptr(&command), buffer_len(&command));
830: packet_send();
831: packet_write_wait();
832: } else {
833: debug("Requesting shell.");
834: packet_start(SSH_CMSG_EXEC_SHELL);
835: packet_send();
836: packet_write_wait();
837: }
838:
839: /* Enter the interactive session. */
1.45 markus 840: return client_loop(have_tty, tty_flag ? options.escape_char : -1);
841: }
842:
843: void
844: init_local_fwd(void)
845: {
846: int i;
847: /* Initiate local TCP/IP port forwardings. */
848: for (i = 0; i < options.num_local_forwards; i++) {
849: debug("Connections to local port %d forwarded to remote address %.200s:%d",
850: options.local_forwards[i].port,
851: options.local_forwards[i].host,
852: options.local_forwards[i].host_port);
853: channel_request_local_forwarding(options.local_forwards[i].port,
854: options.local_forwards[i].host,
855: options.local_forwards[i].host_port,
856: options.gateway_ports);
857: }
858: }
859:
860: extern void client_set_session_ident(int id);
861:
862: void
863: client_init(int id, void *arg)
864: {
865: int len;
866: debug("client_init id %d arg %d", id, (int)arg);
1.31 markus 867:
1.45 markus 868: if (no_shell_flag)
869: goto done;
870:
871: if (tty_flag) {
872: struct winsize ws;
873: char *cp;
874: cp = getenv("TERM");
875: if (!cp)
876: cp = "";
877: /* Store window size in the packet. */
878: if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
879: memset(&ws, 0, sizeof(ws));
880:
881: channel_request_start(id, "pty-req", 0);
882: packet_put_cstring(cp);
883: packet_put_int(ws.ws_col);
884: packet_put_int(ws.ws_row);
885: packet_put_int(ws.ws_xpixel);
886: packet_put_int(ws.ws_ypixel);
887: packet_put_cstring(""); /* XXX: encode terminal modes */
888: packet_send();
889: /* XXX wait for reply */
890: }
891: len = buffer_len(&command);
892: if (len > 0) {
893: if (len > 900)
894: len = 900;
895: debug("Sending command: %.*s", len, buffer_ptr(&command));
896: channel_request_start(id, "exec", 0);
897: packet_put_string(buffer_ptr(&command), len);
898: packet_send();
899: } else {
900: channel_request(id, "shell", 0);
901: }
902: /* channel_callback(id, SSH2_MSG_OPEN_CONFIGMATION, client_init, 0); */
903: done:
904: /* register different callback, etc. XXX */
905: client_set_session_ident(id);
906: }
907:
908: int
909: ssh_session2(void)
910: {
911: int window, packetmax, id;
912: int in = dup(STDIN_FILENO);
913: int out = dup(STDOUT_FILENO);
914: int err = dup(STDERR_FILENO);
915:
916: if (in < 0 || out < 0 || err < 0)
917: fatal("dump in/out/err failed");
918:
919: /* should be pre-session */
920: init_local_fwd();
921:
922: window = 32*1024;
923: if (tty_flag) {
924: packetmax = window/8;
925: } else {
926: window *= 2;
927: packetmax = window/2;
928: }
929:
930: id = channel_new(
931: "session", SSH_CHANNEL_OPENING, in, out, err,
932: window, packetmax, CHAN_EXTENDED_WRITE, xstrdup("client-session"));
933:
934:
935: channel_open(id);
936: channel_register_callback(id, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, client_init, (void *)0);
1.31 markus 937:
1.45 markus 938: return client_loop(tty_flag, tty_flag ? options.escape_char : -1);
1.1 deraadt 939: }
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