Annotation of src/usr.bin/ssh/ssh.c, Revision 1.22
1.1 deraadt 1: /*
2:
3: ssh.c
4:
5: Author: Tatu Ylonen <ylo@cs.hut.fi>
6:
7: Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
8: All rights reserved
9:
10: Created: Sat Mar 18 16:36:11 1995 ylo
11:
12: Ssh client program. This program can be used to log into a remote machine.
13: The software supports strong authentication, encryption, and forwarding
14: of X11, TCP/IP, and authentication connections.
15:
1.2 provos 16: Modified to work with SSL by Niels Provos <provos@citi.umich.edu> in Canada.
17:
1.1 deraadt 18: */
19:
20: #include "includes.h"
1.22 ! provos 21: RCSID("$Id: ssh.c,v 1.21 1999/09/30 20:39:08 deraadt Exp $");
1.1 deraadt 22:
23: #include "xmalloc.h"
24: #include "ssh.h"
25: #include "packet.h"
26: #include "buffer.h"
27: #include "authfd.h"
28: #include "readconf.h"
29: #include "uidswap.h"
30:
31: /* Flag indicating whether debug mode is on. This can be set on the
32: command line. */
33: int debug_flag = 0;
34:
35: /* Flag indicating whether quiet mode is on. */
36: int quiet_flag = 0;
37:
38: /* Flag indicating whether to allocate a pseudo tty. This can be set on the
39: command line, and is automatically set if no command is given on the command
40: line. */
41: int tty_flag = 0;
42:
43: /* Flag indicating that nothing should be read from stdin. This can be set
44: on the command line. */
45: int stdin_null_flag = 0;
46:
47: /* Flag indicating that ssh should fork after authentication. This is useful
48: so that the pasphrase can be entered manually, and then ssh goes to the
49: background. */
50: int fork_after_authentication_flag = 0;
51:
52: /* General data structure for command line options and options configurable
53: in configuration files. See readconf.h. */
54: Options options;
55:
56: /* Name of the host we are connecting to. This is the name given on the
57: command line, or the HostName specified for the user-supplied name
58: in a configuration file. */
59: char *host;
60:
1.22 ! provos 61: /* socket address the host resolves to */
! 62: struct sockaddr_in hostaddr;
! 63:
1.1 deraadt 64: /* Flag to indicate that we have received a window change signal which has
65: not yet been processed. This will cause a message indicating the new
66: window size to be sent to the server a little later. This is volatile
67: because this is updated in a signal handler. */
68: volatile int received_window_change_signal = 0;
69:
70: /* Value of argv[0] (set in the main program). */
71: char *av0;
72:
73: /* Flag indicating whether we have a valid host private key loaded. */
74: int host_private_key_loaded = 0;
75:
76: /* Host private key. */
1.2 provos 77: RSA *host_private_key = NULL;
1.1 deraadt 78:
1.10 dugsong 79: /* Original real UID. */
80: uid_t original_real_uid;
1.1 deraadt 81:
82: /* Prints a help message to the user. This function never returns. */
83:
1.2 provos 84: void
85: usage()
1.1 deraadt 86: {
87: fprintf(stderr, "Usage: %s [options] host [command]\n", av0);
88: fprintf(stderr, "Options:\n");
89: fprintf(stderr, " -l user Log in using this user name.\n");
90: fprintf(stderr, " -n Redirect input from /dev/null.\n");
1.7 provos 91: fprintf(stderr, " -a Disable authentication agent forwarding.\n");
1.9 dugsong 92: #ifdef AFS
93: fprintf(stderr, " -k Disable Kerberos ticket and AFS token forwarding.\n");
94: #endif /* AFS */
1.1 deraadt 95: fprintf(stderr, " -x Disable X11 connection forwarding.\n");
96: fprintf(stderr, " -i file Identity for RSA authentication (default: ~/.ssh/identity).\n");
97: fprintf(stderr, " -t Tty; allocate a tty even if command is given.\n");
98: fprintf(stderr, " -v Verbose; display verbose debugging messages.\n");
1.8 provos 99: fprintf(stderr, " -V Display version number only.\n");
1.1 deraadt 100: fprintf(stderr, " -q Quiet; don't display any warning messages.\n");
101: fprintf(stderr, " -f Fork into background after authentication.\n");
102: fprintf(stderr, " -e char Set escape character; ``none'' = disable (default: ~).\n");
103:
1.19 provos 104: fprintf(stderr, " -c cipher Select encryption algorithm: "
105: "``3des'', "
106: "``blowfish''\n");
1.1 deraadt 107: fprintf(stderr, " -p port Connect to this port. Server must be on the same port.\n");
108: fprintf(stderr, " -L listen-port:host:port Forward local port to remote address\n");
109: fprintf(stderr, " -R listen-port:host:port Forward remote port to local address\n");
110: fprintf(stderr, " These cause %s to listen for connections on a port, and\n", av0);
111: fprintf(stderr, " forward them to the other side by connecting to host:port.\n");
112: fprintf(stderr, " -C Enable compression.\n");
1.21 deraadt 113: fprintf(stderr, " -g Allow remote hosts to connect to forwarded ports.\n");
1.1 deraadt 114: fprintf(stderr, " -o 'option' Process the option as if it was read from a configuration file.\n");
115: exit(1);
116: }
117:
118: /* Connects to the given host using rsh (or prints an error message and exits
119: if rsh is not available). This function never returns. */
120:
1.2 provos 121: void
122: rsh_connect(char *host, char *user, Buffer *command)
1.1 deraadt 123: {
124: char *args[10];
125: int i;
126:
127: log("Using rsh. WARNING: Connection will not be encrypted.");
128: /* Build argument list for rsh. */
129: i = 0;
1.13 deraadt 130: args[i++] = _PATH_RSH;
1.1 deraadt 131: args[i++] = host; /* may have to come after user on some systems */
132: if (user)
133: {
134: args[i++] = "-l";
135: args[i++] = user;
136: }
137: if (buffer_len(command) > 0)
138: {
139: buffer_append(command, "\0", 1);
140: args[i++] = buffer_ptr(command);
141: }
142: args[i++] = NULL;
143: if (debug_flag)
144: {
145: for (i = 0; args[i]; i++)
146: {
147: if (i != 0)
148: fprintf(stderr, " ");
149: fprintf(stderr, "%s", args[i]);
150: }
151: fprintf(stderr, "\n");
152: }
1.13 deraadt 153: execv(_PATH_RSH, args);
154: perror(_PATH_RSH);
1.1 deraadt 155: exit(1);
156: }
157:
158: /* Main program for the ssh client. */
159:
1.11 deraadt 160: uid_t original_real_uid;
161:
1.2 provos 162: int
163: main(int ac, char **av)
1.1 deraadt 164: {
165: int i, opt, optind, type, exit_status, ok, fwd_port, fwd_host_port, authfd;
166: char *optarg, *cp, buf[256];
167: Buffer command;
168: struct winsize ws;
169: struct stat st;
170: struct passwd *pw, pwcopy;
171: int interactive = 0, dummy;
172: uid_t original_effective_uid;
173: int plen;
174:
175: /* Save the original real uid. It will be needed later (uid-swapping may
176: clobber the real uid). */
177: original_real_uid = getuid();
178: original_effective_uid = geteuid();
179:
180: /* If we are installed setuid root be careful to not drop core. */
181: if (original_real_uid != original_effective_uid)
182: {
183: struct rlimit rlim;
184: rlim.rlim_cur = rlim.rlim_max = 0;
185: if (setrlimit(RLIMIT_CORE, &rlim) < 0)
186: fatal("setrlimit failed: %.100s", strerror(errno));
187: }
188:
189: /* Use uid-swapping to give up root privileges for the duration of option
190: processing. We will re-instantiate the rights when we are ready to
191: create the privileged port, and will permanently drop them when the
192: port has been created (actually, when the connection has been made, as
193: we may need to create the port several times). */
194: temporarily_use_uid(original_real_uid);
195:
196: /* Set our umask to something reasonable, as some files are created with
197: the default umask. This will make them world-readable but writable
198: only by the owner, which is ok for all files for which we don't set
199: the modes explicitly. */
200: umask(022);
201:
202: /* Save our own name. */
203: av0 = av[0];
204:
205: /* Initialize option structure to indicate that no values have been set. */
206: initialize_options(&options);
207:
208: /* Parse command-line arguments. */
209: host = NULL;
210:
211: /* If program name is not one of the standard names, use it as host name. */
212: if (strchr(av0, '/'))
213: cp = strrchr(av0, '/') + 1;
214: else
215: cp = av0;
216: if (strcmp(cp, "rsh") != 0 && strcmp(cp, "ssh") != 0 &&
217: strcmp(cp, "rlogin") != 0 && strcmp(cp, "slogin") != 0)
218: host = cp;
219:
220: for (optind = 1; optind < ac; optind++)
221: {
222: if (av[optind][0] != '-')
223: {
224: if (host)
225: break;
1.3 deraadt 226: if ((cp = strchr(av[optind], '@'))) {
227: options.user = av[optind];
228: *cp = '\0';
229: host = ++cp;
230: }
231: else
232: host = av[optind];
1.1 deraadt 233: continue;
234: }
235: opt = av[optind][1];
236: if (!opt)
237: usage();
238: if (strchr("eilcpLRo", opt)) /* options with arguments */
239: {
240: optarg = av[optind] + 2;
241: if (strcmp(optarg, "") == 0)
242: {
243: if (optind >= ac - 1)
244: usage();
245: optarg = av[++optind];
246: }
247: }
248: else
249: {
250: if (av[optind][2])
251: usage();
252: optarg = NULL;
253: }
254: switch (opt)
255: {
256: case 'n':
257: stdin_null_flag = 1;
258: break;
259:
260: case 'f':
261: fork_after_authentication_flag = 1;
262: stdin_null_flag = 1;
263: break;
264:
265: case 'x':
266: options.forward_x11 = 0;
267: break;
268:
269: case 'X':
270: options.forward_x11 = 1;
1.4 deraadt 271: break;
272:
273: case 'g':
274: options.gateway_ports = 1;
1.1 deraadt 275: break;
276:
277: case 'a':
278: options.forward_agent = 0;
1.9 dugsong 279: break;
280: #ifdef AFS
281: case 'k':
1.1 deraadt 282: options.kerberos_tgt_passing = 0;
283: options.afs_token_passing = 0;
1.9 dugsong 284: break;
1.1 deraadt 285: #endif
286: case 'i':
287: if (stat(optarg, &st) < 0)
288: {
289: fprintf(stderr, "Warning: Identity file %s does not exist.\n",
290: optarg);
291: break;
292: }
293: if (options.num_identity_files >= SSH_MAX_IDENTITY_FILES)
294: fatal("Too many identity files specified (max %d)",
295: SSH_MAX_IDENTITY_FILES);
296: options.identity_files[options.num_identity_files++] =
297: xstrdup(optarg);
298: break;
299:
300: case 't':
301: tty_flag = 1;
302: break;
303:
304: case 'v':
1.6 deraadt 305: case 'V':
1.1 deraadt 306: debug_flag = 1;
307: fprintf(stderr, "SSH Version %s, protocol version %d.%d.\n",
308: SSH_VERSION, PROTOCOL_MAJOR, PROTOCOL_MINOR);
309: fprintf(stderr, "Compiled with SSL.\n");
1.6 deraadt 310: if (opt == 'V')
311: exit(0);
1.1 deraadt 312: break;
313:
314: case 'q':
315: quiet_flag = 1;
316: break;
317:
318: case 'e':
319: if (optarg[0] == '^' && optarg[2] == 0 &&
320: (unsigned char)optarg[1] >= 64 && (unsigned char)optarg[1] < 128)
321: options.escape_char = (unsigned char)optarg[1] & 31;
322: else
323: if (strlen(optarg) == 1)
324: options.escape_char = (unsigned char)optarg[0];
325: else
326: if (strcmp(optarg, "none") == 0)
327: options.escape_char = -2;
328: else
329: {
330: fprintf(stderr, "Bad escape character '%s'.\n", optarg);
331: exit(1);
332: }
333: break;
334:
335: case 'c':
336: options.cipher = cipher_number(optarg);
337: if (options.cipher == -1)
338: {
339: fprintf(stderr, "Unknown cipher type '%s'\n", optarg);
340: exit(1);
341: }
342: break;
343:
344: case 'p':
345: options.port = atoi(optarg);
346: if (options.port < 1 || options.port > 65535)
347: {
348: fprintf(stderr, "Bad port %s.\n", optarg);
349: exit(1);
350: }
351: break;
352:
353: case 'l':
354: options.user = optarg;
355: break;
356:
357: case 'R':
358: if (sscanf(optarg, "%d:%255[^:]:%d", &fwd_port, buf,
359: &fwd_host_port) != 3)
360: {
361: fprintf(stderr, "Bad forwarding specification '%s'.\n", optarg);
362: usage();
363: /*NOTREACHED*/
364: }
365: add_remote_forward(&options, fwd_port, buf, fwd_host_port);
366: break;
367:
368: case 'L':
369: if (sscanf(optarg, "%d:%255[^:]:%d", &fwd_port, buf,
370: &fwd_host_port) != 3)
371: {
372: fprintf(stderr, "Bad forwarding specification '%s'.\n", optarg);
373: usage();
374: /*NOTREACHED*/
375: }
376: add_local_forward(&options, fwd_port, buf, fwd_host_port);
377: break;
378:
379: case 'C':
380: options.compression = 1;
381: break;
382:
383: case 'o':
384: dummy = 1;
385: process_config_line(&options, host ? host : "", optarg,
386: "command-line", 0, &dummy);
387: break;
388:
389: default:
390: usage();
391: }
392: }
393:
394: /* Check that we got a host name. */
395: if (!host)
396: usage();
1.5 deraadt 397:
398: /* check if RSA support exists */
399: if (rsa_alive() == 0) {
400: extern char *__progname;
401:
402: fprintf(stderr,
403: "%s: no RSA support in libssl and libcrypto. See ssl(8).\n",
404: __progname);
405: exit(1);
406: }
1.1 deraadt 407:
408: /* Initialize the command to execute on remote host. */
409: buffer_init(&command);
410:
411: /* Save the command to execute on the remote host in a buffer. There is
412: no limit on the length of the command, except by the maximum packet
413: size. Also sets the tty flag if there is no command. */
414: if (optind == ac)
415: {
416: /* No command specified - execute shell on a tty. */
417: tty_flag = 1;
418: }
419: else
420: {
421: /* A command has been specified. Store it into the buffer. */
422: for (i = optind; i < ac; i++)
423: {
424: if (i > optind)
425: buffer_append(&command, " ", 1);
426: buffer_append(&command, av[i], strlen(av[i]));
427: }
428: }
429:
430: /* Cannot fork to background if no command. */
431: if (fork_after_authentication_flag && buffer_len(&command) == 0)
432: fatal("Cannot fork into background without a command to execute.");
433:
434: /* Allocate a tty by default if no command specified. */
435: if (buffer_len(&command) == 0)
436: tty_flag = 1;
437:
438: /* Do not allocate a tty if stdin is not a tty. */
439: if (!isatty(fileno(stdin)))
440: {
441: if (tty_flag)
442: fprintf(stderr, "Pseudo-terminal will not be allocated because stdin is not a terminal.\n");
443: tty_flag = 0;
444: }
445:
446: /* Get user data. */
447: pw = getpwuid(original_real_uid);
448: if (!pw)
449: {
450: fprintf(stderr, "You don't exist, go away!\n");
451: exit(1);
452: }
453:
454: /* Take a copy of the returned structure. */
455: memset(&pwcopy, 0, sizeof(pwcopy));
456: pwcopy.pw_name = xstrdup(pw->pw_name);
457: pwcopy.pw_passwd = xstrdup(pw->pw_passwd);
458: pwcopy.pw_uid = pw->pw_uid;
459: pwcopy.pw_gid = pw->pw_gid;
460: pwcopy.pw_dir = xstrdup(pw->pw_dir);
461: pwcopy.pw_shell = xstrdup(pw->pw_shell);
462: pw = &pwcopy;
463:
464: /* Initialize "log" output. Since we are the client all output actually
465: goes to the terminal. */
466: log_init(av[0], 1, debug_flag, quiet_flag, SYSLOG_FACILITY_USER);
467:
468: /* Read per-user configuration file. */
1.11 deraadt 469: snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir, SSH_USER_CONFFILE);
1.1 deraadt 470: read_config_file(buf, host, &options);
471:
472: /* Read systemwide configuration file. */
473: read_config_file(HOST_CONFIG_FILE, host, &options);
474:
475: /* Fill configuration defaults. */
476: fill_default_options(&options);
477: if (options.user == NULL)
478: options.user = xstrdup(pw->pw_name);
479:
480: if (options.hostname != NULL)
481: host = options.hostname;
482:
483: /* Find canonic host name. */
484: if (strchr(host, '.') == 0)
485: {
486: struct hostent *hp = gethostbyname(host);
487: if (hp != 0)
488: {
489: if (strchr(hp->h_name, '.') != 0)
490: host = xstrdup(hp->h_name);
491: else if (hp->h_aliases != 0
492: && hp->h_aliases[0] != 0
493: && strchr(hp->h_aliases[0], '.') != 0)
494: host = xstrdup(hp->h_aliases[0]);
495: }
496: }
497:
498: /* Disable rhosts authentication if not running as root. */
499: if (original_effective_uid != 0)
500: {
501: options.rhosts_authentication = 0;
502: options.rhosts_rsa_authentication = 0;
503: }
504:
505: /* If using rsh has been selected, exec it now (without trying anything
506: else). Note that we must release privileges first. */
507: if (options.use_rsh)
508: {
509: /* Restore our superuser privileges. This must be done before
510: permanently setting the uid. */
511: restore_uid();
512:
513: /* Switch to the original uid permanently. */
514: permanently_set_uid(original_real_uid);
515:
516: /* Execute rsh. */
517: rsh_connect(host, options.user, &command);
518: fatal("rsh_connect returned");
519: }
520:
521: /* Restore our superuser privileges. */
522: restore_uid();
523:
524: /* Open a connection to the remote host. This needs root privileges if
1.2 provos 525: rhosts_authentication is true. */
1.22 ! provos 526: ok = ssh_connect(host, &hostaddr, options.port, options.connection_attempts,
1.1 deraadt 527: !options.rhosts_authentication &&
528: !options.rhosts_rsa_authentication,
1.2 provos 529: original_real_uid, options.proxy_command);
1.1 deraadt 530:
531: /* If we successfully made the connection, load the host private key in
532: case we will need it later for combined rsa-rhosts authentication.
533: This must be done before releasing extra privileges, because the file
534: is only readable by root. */
535: if (ok)
536: {
1.2 provos 537: host_private_key = RSA_new();
538: if (load_private_key(HOST_KEY_FILE, "", host_private_key, NULL))
1.1 deraadt 539: host_private_key_loaded = 1;
540: }
541:
542: /* Get rid of any extra privileges that we may have. We will no longer need
543: them. Also, extra privileges could make it very hard to read identity
544: files and other non-world-readable files from the user's home directory
545: if it happens to be on a NFS volume where root is mapped to nobody. */
546: permanently_set_uid(original_real_uid);
547:
548: /* Now that we are back to our own permissions, create ~/.ssh directory
549: if it doesn\'t already exist. */
1.11 deraadt 550: snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir, SSH_USER_DIR);
1.1 deraadt 551: if (stat(buf, &st) < 0)
552: if (mkdir(buf, 0755) < 0)
553: error("Could not create directory '%.200s'.", buf);
554:
555: /* Check if the connection failed, and try "rsh" if appropriate. */
556: if (!ok)
557: {
558: if (options.port != 0)
559: log("Secure connection to %.100s on port %d refused%.100s.",
560: host, options.port,
561: options.fallback_to_rsh ? "; reverting to insecure method" : "");
562: else
563: log("Secure connection to %.100s refused%.100s.", host,
564: options.fallback_to_rsh ? "; reverting to insecure method" : "");
565:
566: if (options.fallback_to_rsh)
567: {
568: rsh_connect(host, options.user, &command);
569: fatal("rsh_connect returned");
570: }
571: exit(1);
572: }
573:
574: /* Expand ~ in options.identity_files. */
575: for (i = 0; i < options.num_identity_files; i++)
576: options.identity_files[i] =
577: tilde_expand_filename(options.identity_files[i], original_real_uid);
578:
579: /* Expand ~ in known host file names. */
580: options.system_hostfile = tilde_expand_filename(options.system_hostfile,
581: original_real_uid);
582: options.user_hostfile = tilde_expand_filename(options.user_hostfile,
583: original_real_uid);
584:
1.2 provos 585: /* Log into the remote system. This never returns if the login fails. */
586: ssh_login(host_private_key_loaded, host_private_key,
1.22 ! provos 587: host, &hostaddr, &options, original_real_uid);
1.1 deraadt 588:
589: /* We no longer need the host private key. Clear it now. */
590: if (host_private_key_loaded)
1.2 provos 591: RSA_free(host_private_key); /* Destroys contents safely */
1.1 deraadt 592:
593: /* Close connection cleanly after attack. */
594: cipher_attack_detected = packet_disconnect;
595:
596: /* If requested, fork and let ssh continue in the background. */
597: if (fork_after_authentication_flag)
598: {
599: int ret = fork();
600: if (ret == -1)
601: fatal("fork failed: %.100s", strerror(errno));
602: if (ret != 0)
603: exit(0);
604: setsid();
605: }
606:
607: /* Enable compression if requested. */
608: if (options.compression)
609: {
610: debug("Requesting compression at level %d.", options.compression_level);
611:
612: if (options.compression_level < 1 || options.compression_level > 9)
613: fatal("Compression level must be from 1 (fast) to 9 (slow, best).");
614:
615: /* Send the request. */
616: packet_start(SSH_CMSG_REQUEST_COMPRESSION);
617: packet_put_int(options.compression_level);
618: packet_send();
619: packet_write_wait();
620: type = packet_read(&plen);
621: if (type == SSH_SMSG_SUCCESS)
622: packet_start_compression(options.compression_level);
623: else if (type == SSH_SMSG_FAILURE)
624: log("Warning: Remote host refused compression.");
625: else
626: packet_disconnect("Protocol error waiting for compression response.");
627: }
628:
629: /* Allocate a pseudo tty if appropriate. */
630: if (tty_flag)
631: {
632: debug("Requesting pty.");
633:
634: /* Start the packet. */
635: packet_start(SSH_CMSG_REQUEST_PTY);
636:
637: /* Store TERM in the packet. There is no limit on the length of the
638: string. */
639: cp = getenv("TERM");
640: if (!cp)
641: cp = "";
642: packet_put_string(cp, strlen(cp));
643:
644: /* Store window size in the packet. */
645: if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
646: memset(&ws, 0, sizeof(ws));
647: packet_put_int(ws.ws_row);
648: packet_put_int(ws.ws_col);
649: packet_put_int(ws.ws_xpixel);
650: packet_put_int(ws.ws_ypixel);
651:
652: /* Store tty modes in the packet. */
653: tty_make_modes(fileno(stdin));
654:
655: /* Send the packet, and wait for it to leave. */
656: packet_send();
657: packet_write_wait();
658:
659: /* Read response from the server. */
660: type = packet_read(&plen);
661: if (type == SSH_SMSG_SUCCESS)
662: interactive = 1;
663: else if (type == SSH_SMSG_FAILURE)
664: log("Warning: Remote host failed or refused to allocate a pseudo tty.");
665: else
666: packet_disconnect("Protocol error waiting for pty request response.");
667: }
668:
669: /* Request X11 forwarding if enabled and DISPLAY is set. */
670: if (options.forward_x11 && getenv("DISPLAY") != NULL)
671: {
672: char line[512], proto[512], data[512];
673: FILE *f;
674: int forwarded = 0, got_data = 0, i;
675:
676: #ifdef XAUTH_PATH
677: /* Try to get Xauthority information for the display. */
1.11 deraadt 678: snprintf(line, sizeof line, "%.100s list %.200s 2>/dev/null",
1.1 deraadt 679: XAUTH_PATH, getenv("DISPLAY"));
680: f = popen(line, "r");
681: if (f && fgets(line, sizeof(line), f) &&
682: sscanf(line, "%*s %s %s", proto, data) == 2)
683: got_data = 1;
684: if (f)
685: pclose(f);
686: #endif /* XAUTH_PATH */
687: /* If we didn't get authentication data, just make up some data. The
688: forwarding code will check the validity of the response anyway, and
689: substitute this data. The X11 server, however, will ignore this
690: fake data and use whatever authentication mechanisms it was using
691: otherwise for the local connection. */
692: if (!got_data)
693: {
1.9 dugsong 694: u_int32_t rand = 0;
1.2 provos 695:
1.11 deraadt 696: strlcpy(proto, "MIT-MAGIC-COOKIE-1", sizeof proto);
1.2 provos 697: for (i = 0; i < 16; i++) {
698: if (i % 4 == 0)
699: rand = arc4random();
1.11 deraadt 700: snprintf(data + 2 * i, sizeof data - 2 * i, "%02x", rand & 0xff);
1.2 provos 701: rand >>= 8;
702: }
1.1 deraadt 703: }
704:
705: /* Got local authentication reasonable information. Request forwarding
706: with authentication spoofing. */
707: debug("Requesting X11 forwarding with authentication spoofing.");
1.2 provos 708: x11_request_forwarding_with_spoofing(proto, data);
1.1 deraadt 709:
710: /* Read response from the server. */
711: type = packet_read(&plen);
712: if (type == SSH_SMSG_SUCCESS)
713: {
714: forwarded = 1;
715: interactive = 1;
716: }
717: else if (type == SSH_SMSG_FAILURE)
718: log("Warning: Remote host denied X11 forwarding.");
719: else
720: packet_disconnect("Protocol error waiting for X11 forwarding");
721: }
722:
723: /* Tell the packet module whether this is an interactive session. */
724: packet_set_interactive(interactive, options.keepalives);
725:
726: /* Clear agent forwarding if we don\'t have an agent. */
727: authfd = ssh_get_authentication_fd();
728: if (authfd < 0)
729: options.forward_agent = 0;
730: else
731: ssh_close_authentication_socket(authfd);
732:
733: /* Request authentication agent forwarding if appropriate. */
734: if (options.forward_agent)
735: {
736: debug("Requesting authentication agent forwarding.");
737: auth_request_forwarding();
738:
739: /* Read response from the server. */
740: type = packet_read(&plen);
741: packet_integrity_check(plen, 0, type);
742: if (type != SSH_SMSG_SUCCESS)
743: log("Warning: Remote host denied authentication agent forwarding.");
744: }
745:
746: /* Initiate local TCP/IP port forwardings. */
747: for (i = 0; i < options.num_local_forwards; i++)
748: {
749: debug("Connections to local port %d forwarded to remote address %.200s:%d",
750: options.local_forwards[i].port, options.local_forwards[i].host,
751: options.local_forwards[i].host_port);
752: channel_request_local_forwarding(options.local_forwards[i].port,
753: options.local_forwards[i].host,
754: options.local_forwards[i].host_port);
755: }
756:
757: /* Initiate remote TCP/IP port forwardings. */
758: for (i = 0; i < options.num_remote_forwards; i++)
759: {
760: debug("Connections to remote port %d forwarded to local address %.200s:%d",
761: options.remote_forwards[i].port, options.remote_forwards[i].host,
762: options.remote_forwards[i].host_port);
763: channel_request_remote_forwarding(options.remote_forwards[i].port,
764: options.remote_forwards[i].host,
765: options.remote_forwards[i].host_port);
766: }
767:
768: /* If a command was specified on the command line, execute the command now.
769: Otherwise request the server to start a shell. */
770: if (buffer_len(&command) > 0)
771: {
772: int len = buffer_len(&command);
773: if (len > 900)
774: len = 900;
775: debug("Sending command: %.*s", len, buffer_ptr(&command));
776: packet_start(SSH_CMSG_EXEC_CMD);
777: packet_put_string(buffer_ptr(&command), buffer_len(&command));
778: packet_send();
779: packet_write_wait();
780: }
781: else
782: {
783: debug("Requesting shell.");
784: packet_start(SSH_CMSG_EXEC_SHELL);
785: packet_send();
786: packet_write_wait();
787: }
788:
789: /* Enter the interactive session. */
790: exit_status = client_loop(tty_flag, tty_flag ? options.escape_char : -1);
791:
792: /* Close the connection to the remote host. */
793: packet_close();
794:
795: /* Exit with the status returned by the program on the remote side. */
796: exit(exit_status);
797: }
![[BACK]](/icons/back.gif){kind=icon}
Return to ssh.c CVS log ![[TXT]](/icons/text.gif){kind=icon}
![[DIR]](/icons/dir.gif){kind=icon}
Up to [local] / src / usr.bin / ssh