Annotation of src/usr.bin/ssh/ssh.c, Revision 1.51
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"
1.51 ! markus 14: RCSID("$Id: ssh.c,v 1.50 2000/04/28 08:10:20 markus Exp $");
1.49 markus 15:
16: #include <openssl/evp.h>
17: #include <openssl/dsa.h>
18: #include <openssl/rsa.h>
1.1 deraadt 19:
20: #include "xmalloc.h"
21: #include "ssh.h"
22: #include "packet.h"
23: #include "buffer.h"
24: #include "authfd.h"
25: #include "readconf.h"
26: #include "uidswap.h"
1.45 markus 27:
28: #include "ssh2.h"
29: #include "compat.h"
1.44 markus 30: #include "channels.h"
1.49 markus 31: #include "key.h"
32: #include "authfile.h"
33:
34: extern char *__progname;
1.1 deraadt 35:
1.37 markus 36: /* Flag indicating whether IPv4 or IPv6. This can be set on the command line.
37: Default value is AF_UNSPEC means both IPv4 and IPv6. */
38: int IPv4or6 = AF_UNSPEC;
39:
1.31 markus 40: /* Flag indicating whether debug mode is on. This can be set on the command line. */
1.1 deraadt 41: int debug_flag = 0;
42:
1.46 markus 43: /* Flag indicating whether a tty should be allocated */
1.1 deraadt 44: int tty_flag = 0;
45:
1.45 markus 46: /* don't exec a shell */
47: int no_shell_flag = 0;
48: int no_tty_flag = 0;
49:
1.33 markus 50: /*
51: * Flag indicating that nothing should be read from stdin. This can be set
52: * on the command line.
53: */
1.1 deraadt 54: int stdin_null_flag = 0;
55:
1.33 markus 56: /*
57: * Flag indicating that ssh should fork after authentication. This is useful
58: * so that the pasphrase can be entered manually, and then ssh goes to the
59: * background.
60: */
1.1 deraadt 61: int fork_after_authentication_flag = 0;
62:
1.33 markus 63: /*
64: * General data structure for command line options and options configurable
65: * in configuration files. See readconf.h.
66: */
1.1 deraadt 67: Options options;
68:
1.33 markus 69: /*
70: * Name of the host we are connecting to. This is the name given on the
71: * command line, or the HostName specified for the user-supplied name in a
72: * configuration file.
73: */
1.1 deraadt 74: char *host;
75:
1.22 provos 76: /* socket address the host resolves to */
1.37 markus 77: struct sockaddr_storage hostaddr;
1.22 provos 78:
1.33 markus 79: /*
80: * Flag to indicate that we have received a window change signal which has
81: * not yet been processed. This will cause a message indicating the new
82: * window size to be sent to the server a little later. This is volatile
83: * because this is updated in a signal handler.
84: */
1.1 deraadt 85: volatile int received_window_change_signal = 0;
86:
87: /* Value of argv[0] (set in the main program). */
88: char *av0;
89:
90: /* Flag indicating whether we have a valid host private key loaded. */
91: int host_private_key_loaded = 0;
92:
93: /* Host private key. */
1.2 provos 94: RSA *host_private_key = NULL;
1.1 deraadt 95:
1.10 dugsong 96: /* Original real UID. */
97: uid_t original_real_uid;
1.1 deraadt 98:
1.45 markus 99: /* command to be executed */
100: Buffer command;
101:
1.1 deraadt 102: /* Prints a help message to the user. This function never returns. */
103:
1.2 provos 104: void
105: usage()
1.1 deraadt 106: {
1.31 markus 107: fprintf(stderr, "Usage: %s [options] host [command]\n", av0);
108: fprintf(stderr, "Options:\n");
109: fprintf(stderr, " -l user Log in using this user name.\n");
110: fprintf(stderr, " -n Redirect input from /dev/null.\n");
111: fprintf(stderr, " -a Disable authentication agent forwarding.\n");
1.9 dugsong 112: #ifdef AFS
1.31 markus 113: fprintf(stderr, " -k Disable Kerberos ticket and AFS token forwarding.\n");
114: #endif /* AFS */
115: fprintf(stderr, " -x Disable X11 connection forwarding.\n");
116: fprintf(stderr, " -i file Identity for RSA authentication (default: ~/.ssh/identity).\n");
117: fprintf(stderr, " -t Tty; allocate a tty even if command is given.\n");
1.45 markus 118: fprintf(stderr, " -T Do not allocate a tty.\n");
1.31 markus 119: fprintf(stderr, " -v Verbose; display verbose debugging messages.\n");
120: fprintf(stderr, " -V Display version number only.\n");
121: fprintf(stderr, " -P Don't allocate a privileged port.\n");
122: fprintf(stderr, " -q Quiet; don't display any warning messages.\n");
123: fprintf(stderr, " -f Fork into background after authentication.\n");
124: fprintf(stderr, " -e char Set escape character; ``none'' = disable (default: ~).\n");
125:
126: fprintf(stderr, " -c cipher Select encryption algorithm: "
127: "``3des'', "
128: "``blowfish''\n");
129: fprintf(stderr, " -p port Connect to this port. Server must be on the same port.\n");
130: fprintf(stderr, " -L listen-port:host:port Forward local port to remote address\n");
131: fprintf(stderr, " -R listen-port:host:port Forward remote port to local address\n");
132: fprintf(stderr, " These cause %s to listen for connections on a port, and\n", av0);
133: fprintf(stderr, " forward them to the other side by connecting to host:port.\n");
134: fprintf(stderr, " -C Enable compression.\n");
1.45 markus 135: fprintf(stderr, " -N Do not execute a shell or command.\n");
1.31 markus 136: fprintf(stderr, " -g Allow remote hosts to connect to forwarded ports.\n");
1.37 markus 137: fprintf(stderr, " -4 Use IPv4 only.\n");
138: fprintf(stderr, " -6 Use IPv6 only.\n");
1.47 markus 139: fprintf(stderr, " -2 Force protocol version 2.\n");
1.31 markus 140: fprintf(stderr, " -o 'option' Process the option as if it was read from a configuration file.\n");
141: exit(1);
1.1 deraadt 142: }
143:
1.32 deraadt 144: /*
145: * Connects to the given host using rsh (or prints an error message and exits
146: * if rsh is not available). This function never returns.
147: */
1.2 provos 148: void
1.31 markus 149: rsh_connect(char *host, char *user, Buffer * command)
1.1 deraadt 150: {
1.31 markus 151: char *args[10];
152: int i;
153:
154: log("Using rsh. WARNING: Connection will not be encrypted.");
155: /* Build argument list for rsh. */
156: i = 0;
157: args[i++] = _PATH_RSH;
158: /* host may have to come after user on some systems */
159: args[i++] = host;
160: if (user) {
161: args[i++] = "-l";
162: args[i++] = user;
163: }
164: if (buffer_len(command) > 0) {
165: buffer_append(command, "\0", 1);
166: args[i++] = buffer_ptr(command);
167: }
168: args[i++] = NULL;
169: if (debug_flag) {
170: for (i = 0; args[i]; i++) {
171: if (i != 0)
172: fprintf(stderr, " ");
173: fprintf(stderr, "%s", args[i]);
174: }
175: fprintf(stderr, "\n");
176: }
177: execv(_PATH_RSH, args);
178: perror(_PATH_RSH);
179: exit(1);
1.1 deraadt 180: }
181:
1.45 markus 182: int ssh_session(void);
183: int ssh_session2(void);
184:
1.32 deraadt 185: /*
186: * Main program for the ssh client.
187: */
1.2 provos 188: int
189: main(int ac, char **av)
1.1 deraadt 190: {
1.45 markus 191: int i, opt, optind, exit_status, ok;
1.35 markus 192: u_short fwd_port, fwd_host_port;
1.31 markus 193: char *optarg, *cp, buf[256];
194: struct stat st;
195: struct passwd *pw, pwcopy;
1.45 markus 196: int dummy;
1.31 markus 197: uid_t original_effective_uid;
198:
1.33 markus 199: /*
200: * Save the original real uid. It will be needed later (uid-swapping
201: * may clobber the real uid).
202: */
1.31 markus 203: original_real_uid = getuid();
204: original_effective_uid = geteuid();
205:
206: /* If we are installed setuid root be careful to not drop core. */
207: if (original_real_uid != original_effective_uid) {
208: struct rlimit rlim;
209: rlim.rlim_cur = rlim.rlim_max = 0;
210: if (setrlimit(RLIMIT_CORE, &rlim) < 0)
211: fatal("setrlimit failed: %.100s", strerror(errno));
1.1 deraadt 212: }
1.33 markus 213: /*
214: * Use uid-swapping to give up root privileges for the duration of
215: * option processing. We will re-instantiate the rights when we are
216: * ready to create the privileged port, and will permanently drop
217: * them when the port has been created (actually, when the connection
218: * has been made, as we may need to create the port several times).
219: */
1.31 markus 220: temporarily_use_uid(original_real_uid);
221:
1.33 markus 222: /*
223: * Set our umask to something reasonable, as some files are created
224: * with the default umask. This will make them world-readable but
225: * writable only by the owner, which is ok for all files for which we
226: * don't set the modes explicitly.
227: */
1.31 markus 228: umask(022);
229:
230: /* Save our own name. */
231: av0 = av[0];
232:
233: /* Initialize option structure to indicate that no values have been set. */
234: initialize_options(&options);
235:
236: /* Parse command-line arguments. */
237: host = NULL;
238:
239: /* If program name is not one of the standard names, use it as host name. */
240: if (strchr(av0, '/'))
241: cp = strrchr(av0, '/') + 1;
242: else
243: cp = av0;
244: if (strcmp(cp, "rsh") != 0 && strcmp(cp, "ssh") != 0 &&
245: strcmp(cp, "rlogin") != 0 && strcmp(cp, "slogin") != 0)
246: host = cp;
247:
248: for (optind = 1; optind < ac; optind++) {
249: if (av[optind][0] != '-') {
250: if (host)
251: break;
252: if ((cp = strchr(av[optind], '@'))) {
1.48 markus 253: if(cp == av[optind])
254: usage();
1.31 markus 255: options.user = av[optind];
256: *cp = '\0';
257: host = ++cp;
258: } else
259: host = av[optind];
260: continue;
261: }
262: opt = av[optind][1];
263: if (!opt)
264: usage();
265: if (strchr("eilcpLRo", opt)) { /* options with arguments */
266: optarg = av[optind] + 2;
267: if (strcmp(optarg, "") == 0) {
268: if (optind >= ac - 1)
269: usage();
270: optarg = av[++optind];
271: }
272: } else {
273: if (av[optind][2])
274: usage();
275: optarg = NULL;
276: }
277: switch (opt) {
1.47 markus 278: case '2':
279: options.protocol = SSH_PROTO_2;
280: break;
1.37 markus 281: case '4':
282: IPv4or6 = AF_INET;
283: break;
284: case '6':
285: IPv4or6 = AF_INET6;
286: break;
1.31 markus 287: case 'n':
288: stdin_null_flag = 1;
289: break;
290: case 'f':
291: fork_after_authentication_flag = 1;
292: stdin_null_flag = 1;
293: break;
294: case 'x':
295: options.forward_x11 = 0;
296: break;
297: case 'X':
298: options.forward_x11 = 1;
299: break;
300: case 'g':
301: options.gateway_ports = 1;
302: break;
303: case 'P':
304: options.use_privileged_port = 0;
305: break;
306: case 'a':
307: options.forward_agent = 0;
308: break;
1.9 dugsong 309: #ifdef AFS
1.31 markus 310: case 'k':
311: options.kerberos_tgt_passing = 0;
312: options.afs_token_passing = 0;
313: break;
1.1 deraadt 314: #endif
1.31 markus 315: case 'i':
316: if (stat(optarg, &st) < 0) {
317: fprintf(stderr, "Warning: Identity file %s does not exist.\n",
318: optarg);
319: break;
320: }
321: if (options.num_identity_files >= SSH_MAX_IDENTITY_FILES)
322: fatal("Too many identity files specified (max %d)",
323: SSH_MAX_IDENTITY_FILES);
324: options.identity_files[options.num_identity_files++] =
325: xstrdup(optarg);
326: break;
327: case 't':
328: tty_flag = 1;
329: break;
330: case 'v':
331: case 'V':
1.46 markus 332: fprintf(stderr, "SSH Version %s, protocol versions %d.%d/%d.%d.\n",
333: SSH_VERSION,
334: PROTOCOL_MAJOR_1, PROTOCOL_MINOR_1,
335: PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2);
1.45 markus 336: fprintf(stderr, "Compiled with SSL (0x%8.8lx).\n", SSLeay());
1.31 markus 337: if (opt == 'V')
338: exit(0);
339: debug_flag = 1;
340: options.log_level = SYSLOG_LEVEL_DEBUG;
341: break;
342: case 'q':
343: options.log_level = SYSLOG_LEVEL_QUIET;
344: break;
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: case 'c':
1.49 markus 359: if (ciphers_valid(optarg)) {
360: /* SSH2 only */
361: options.ciphers = xstrdup(optarg);
1.51 ! markus 362: options.cipher = SSH_CIPHER_ILLEGAL;
1.49 markus 363: } else {
364: /* SSH1 only */
365: options.cipher = cipher_number(optarg);
366: if (options.cipher == -1) {
367: fprintf(stderr, "Unknown cipher type '%s'\n", optarg);
368: exit(1);
369: }
1.31 markus 370: }
371: break;
372: case 'p':
373: options.port = atoi(optarg);
374: break;
375: case 'l':
376: options.user = optarg;
377: break;
378: case 'R':
1.37 markus 379: if (sscanf(optarg, "%hu/%255[^/]/%hu", &fwd_port, buf,
380: &fwd_host_port) != 3 &&
381: sscanf(optarg, "%hu:%255[^:]:%hu", &fwd_port, buf,
382: &fwd_host_port) != 3) {
1.31 markus 383: fprintf(stderr, "Bad forwarding specification '%s'.\n", optarg);
384: usage();
385: /* NOTREACHED */
386: }
387: add_remote_forward(&options, fwd_port, buf, fwd_host_port);
388: break;
389: case 'L':
1.37 markus 390: if (sscanf(optarg, "%hu/%255[^/]/%hu", &fwd_port, buf,
391: &fwd_host_port) != 3 &&
392: sscanf(optarg, "%hu:%255[^:]:%hu", &fwd_port, buf,
393: &fwd_host_port) != 3) {
1.31 markus 394: fprintf(stderr, "Bad forwarding specification '%s'.\n", optarg);
395: usage();
396: /* NOTREACHED */
397: }
398: add_local_forward(&options, fwd_port, buf, fwd_host_port);
399: break;
400: case 'C':
401: options.compression = 1;
402: break;
1.45 markus 403: case 'N':
404: no_shell_flag = 1;
405: no_tty_flag = 1;
406: break;
407: case 'T':
408: no_tty_flag = 1;
409: break;
1.31 markus 410: case 'o':
411: dummy = 1;
412: if (process_config_line(&options, host ? host : "", optarg,
413: "command-line", 0, &dummy) != 0)
414: exit(1);
415: break;
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:
1.49 markus 425: OpenSSL_add_all_algorithms();
1.31 markus 426:
427: /* Initialize the command to execute on remote host. */
428: buffer_init(&command);
1.1 deraadt 429:
1.33 markus 430: /*
431: * Save the command to execute on the remote host in a buffer. There
432: * is no limit on the length of the command, except by the maximum
433: * packet size. Also sets the tty flag if there is no command.
434: */
1.31 markus 435: if (optind == ac) {
436: /* No command specified - execute shell on a tty. */
437: tty_flag = 1;
438: } else {
439: /* A command has been specified. Store it into the
440: buffer. */
441: for (i = optind; i < ac; i++) {
442: if (i > optind)
443: buffer_append(&command, " ", 1);
444: buffer_append(&command, av[i], strlen(av[i]));
445: }
446: }
447:
448: /* Cannot fork to background if no command. */
449: if (fork_after_authentication_flag && buffer_len(&command) == 0)
450: fatal("Cannot fork into background without a command to execute.");
451:
452: /* Allocate a tty by default if no command specified. */
453: if (buffer_len(&command) == 0)
454: tty_flag = 1;
455:
456: /* Do not allocate a tty if stdin is not a tty. */
457: if (!isatty(fileno(stdin))) {
458: if (tty_flag)
459: fprintf(stderr, "Pseudo-terminal will not be allocated because stdin is not a terminal.\n");
460: tty_flag = 0;
461: }
1.45 markus 462: /* force */
463: if (no_tty_flag)
464: tty_flag = 0;
465:
1.31 markus 466: /* Get user data. */
467: pw = getpwuid(original_real_uid);
468: if (!pw) {
469: fprintf(stderr, "You don't exist, go away!\n");
470: exit(1);
471: }
472: /* Take a copy of the returned structure. */
473: memset(&pwcopy, 0, sizeof(pwcopy));
474: pwcopy.pw_name = xstrdup(pw->pw_name);
475: pwcopy.pw_passwd = xstrdup(pw->pw_passwd);
476: pwcopy.pw_uid = pw->pw_uid;
477: pwcopy.pw_gid = pw->pw_gid;
478: pwcopy.pw_dir = xstrdup(pw->pw_dir);
479: pwcopy.pw_shell = xstrdup(pw->pw_shell);
480: pw = &pwcopy;
481:
482: /* Initialize "log" output. Since we are the client all output
483: actually goes to the terminal. */
484: log_init(av[0], options.log_level, SYSLOG_FACILITY_USER, 0);
485:
486: /* Read per-user configuration file. */
487: snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir, SSH_USER_CONFFILE);
488: read_config_file(buf, host, &options);
489:
490: /* Read systemwide configuration file. */
491: read_config_file(HOST_CONFIG_FILE, host, &options);
492:
493: /* Fill configuration defaults. */
494: fill_default_options(&options);
495:
496: /* reinit */
497: log_init(av[0], options.log_level, SYSLOG_FACILITY_USER, 0);
498:
1.49 markus 499: /* check if RSA support exists */
500: if ((options.protocol & SSH_PROTO_1) &&
501: rsa_alive() == 0) {
502: log("%s: no RSA support in libssl and libcrypto. See ssl(8).",
503: __progname);
504: log("Disabling protocol version 1");
505: options.protocol &= ~ (SSH_PROTO_1|SSH_PROTO_1_PREFERRED);
506: }
507: if (! options.protocol & (SSH_PROTO_1|SSH_PROTO_2)) {
508: fprintf(stderr, "%s: No protocol version available.\n",
509: __progname);
510: exit(1);
511: }
512:
1.31 markus 513: if (options.user == NULL)
514: options.user = xstrdup(pw->pw_name);
515:
516: if (options.hostname != NULL)
517: host = options.hostname;
518:
519: /* Find canonic host name. */
520: if (strchr(host, '.') == 0) {
1.37 markus 521: struct addrinfo hints;
522: struct addrinfo *ai = NULL;
523: int errgai;
524: memset(&hints, 0, sizeof(hints));
1.40 markus 525: hints.ai_family = IPv4or6;
1.37 markus 526: hints.ai_flags = AI_CANONNAME;
1.39 markus 527: hints.ai_socktype = SOCK_STREAM;
1.37 markus 528: errgai = getaddrinfo(host, NULL, &hints, &ai);
529: if (errgai == 0) {
530: if (ai->ai_canonname != NULL)
531: host = xstrdup(ai->ai_canonname);
532: freeaddrinfo(ai);
1.31 markus 533: }
534: }
535: /* Disable rhosts authentication if not running as root. */
536: if (original_effective_uid != 0 || !options.use_privileged_port) {
537: options.rhosts_authentication = 0;
538: options.rhosts_rsa_authentication = 0;
539: }
1.33 markus 540: /*
541: * If using rsh has been selected, exec it now (without trying
542: * anything else). Note that we must release privileges first.
543: */
1.31 markus 544: if (options.use_rsh) {
1.33 markus 545: /*
546: * Restore our superuser privileges. This must be done
547: * before permanently setting the uid.
548: */
1.31 markus 549: restore_uid();
550:
551: /* Switch to the original uid permanently. */
552: permanently_set_uid(original_real_uid);
553:
554: /* Execute rsh. */
555: rsh_connect(host, options.user, &command);
556: fatal("rsh_connect returned");
557: }
558: /* Restore our superuser privileges. */
559: restore_uid();
560:
1.33 markus 561: /*
562: * Open a connection to the remote host. This needs root privileges
563: * if rhosts_{rsa_}authentication is enabled.
564: */
1.31 markus 565:
566: ok = ssh_connect(host, &hostaddr, options.port,
567: options.connection_attempts,
568: !options.rhosts_authentication &&
569: !options.rhosts_rsa_authentication,
570: original_real_uid,
571: options.proxy_command);
572:
1.33 markus 573: /*
574: * If we successfully made the connection, load the host private key
575: * in case we will need it later for combined rsa-rhosts
576: * authentication. This must be done before releasing extra
577: * privileges, because the file is only readable by root.
578: */
1.49 markus 579: if (ok && (options.protocol & SSH_PROTO_1)) {
580: Key k;
1.31 markus 581: host_private_key = RSA_new();
1.49 markus 582: k.type = KEY_RSA;
583: k.rsa = host_private_key;
584: if (load_private_key(HOST_KEY_FILE, "", &k, NULL))
1.31 markus 585: host_private_key_loaded = 1;
586: }
1.33 markus 587: /*
588: * Get rid of any extra privileges that we may have. We will no
589: * longer need them. Also, extra privileges could make it very hard
590: * to read identity files and other non-world-readable files from the
591: * user's home directory if it happens to be on a NFS volume where
592: * root is mapped to nobody.
593: */
594:
595: /*
596: * Note that some legacy systems need to postpone the following call
597: * to permanently_set_uid() until the private hostkey is destroyed
598: * with RSA_free(). Otherwise the calling user could ptrace() the
599: * process, read the private hostkey and impersonate the host.
600: * OpenBSD does not allow ptracing of setuid processes.
601: */
1.31 markus 602: permanently_set_uid(original_real_uid);
603:
1.33 markus 604: /*
605: * Now that we are back to our own permissions, create ~/.ssh
606: * directory if it doesn\'t already exist.
607: */
1.31 markus 608: snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir, SSH_USER_DIR);
609: if (stat(buf, &st) < 0)
610: if (mkdir(buf, 0755) < 0)
611: error("Could not create directory '%.200s'.", buf);
612:
613: /* Check if the connection failed, and try "rsh" if appropriate. */
614: if (!ok) {
615: if (options.port != 0)
1.35 markus 616: log("Secure connection to %.100s on port %hu refused%.100s.",
1.31 markus 617: host, options.port,
618: options.fallback_to_rsh ? "; reverting to insecure method" : "");
619: else
620: log("Secure connection to %.100s refused%.100s.", host,
621: options.fallback_to_rsh ? "; reverting to insecure method" : "");
622:
623: if (options.fallback_to_rsh) {
624: rsh_connect(host, options.user, &command);
625: fatal("rsh_connect returned");
626: }
627: exit(1);
628: }
629: /* Expand ~ in options.identity_files. */
1.49 markus 630: /* XXX mem-leaks */
1.31 markus 631: for (i = 0; i < options.num_identity_files; i++)
632: options.identity_files[i] =
633: tilde_expand_filename(options.identity_files[i], original_real_uid);
1.49 markus 634: for (i = 0; i < options.num_identity_files2; i++)
635: options.identity_files2[i] =
636: tilde_expand_filename(options.identity_files2[i], original_real_uid);
1.31 markus 637: /* Expand ~ in known host file names. */
638: options.system_hostfile = tilde_expand_filename(options.system_hostfile,
1.49 markus 639: original_real_uid);
1.31 markus 640: options.user_hostfile = tilde_expand_filename(options.user_hostfile,
1.49 markus 641: original_real_uid);
642: options.system_hostfile2 = tilde_expand_filename(options.system_hostfile2,
643: original_real_uid);
644: options.user_hostfile2 = tilde_expand_filename(options.user_hostfile2,
645: original_real_uid);
1.31 markus 646:
647: /* Log into the remote system. This never returns if the login fails. */
648: ssh_login(host_private_key_loaded, host_private_key,
1.37 markus 649: host, (struct sockaddr *)&hostaddr, original_real_uid);
1.31 markus 650:
651: /* We no longer need the host private key. Clear it now. */
652: if (host_private_key_loaded)
653: RSA_free(host_private_key); /* Destroys contents safely */
654:
1.45 markus 655: exit_status = compat20 ? ssh_session2() : ssh_session();
656: packet_close();
657: return exit_status;
658: }
659:
1.50 markus 660: void
661: x11_get_proto(char *proto, int proto_len, char *data, int data_len)
662: {
663: char line[512];
664: FILE *f;
665: int got_data = 0, i;
666:
667: #ifdef XAUTH_PATH
668: /* Try to get Xauthority information for the display. */
669: snprintf(line, sizeof line, "%.100s list %.200s 2>/dev/null",
670: XAUTH_PATH, getenv("DISPLAY"));
671: f = popen(line, "r");
672: if (f && fgets(line, sizeof(line), f) &&
673: sscanf(line, "%*s %s %s", proto, data) == 2)
674: got_data = 1;
675: if (f)
676: pclose(f);
677: #endif /* XAUTH_PATH */
678: /*
679: * If we didn't get authentication data, just make up some
680: * data. The forwarding code will check the validity of the
681: * response anyway, and substitute this data. The X11
682: * server, however, will ignore this fake data and use
683: * whatever authentication mechanisms it was using otherwise
684: * for the local connection.
685: */
686: if (!got_data) {
687: u_int32_t rand = 0;
688:
689: strlcpy(proto, "MIT-MAGIC-COOKIE-1", proto_len);
690: for (i = 0; i < 16; i++) {
691: if (i % 4 == 0)
692: rand = arc4random();
693: snprintf(data + 2 * i, data_len - 2 * i, "%02x", rand & 0xff);
694: rand >>= 8;
695: }
696: }
697: }
698:
1.45 markus 699: int
700: ssh_session(void)
701: {
702: int type;
703: int i;
704: int plen;
705: int interactive = 0;
706: int have_tty = 0;
707: struct winsize ws;
708: int authfd;
709: char *cp;
710:
1.31 markus 711: /* Enable compression if requested. */
712: if (options.compression) {
713: debug("Requesting compression at level %d.", options.compression_level);
714:
715: if (options.compression_level < 1 || options.compression_level > 9)
716: fatal("Compression level must be from 1 (fast) to 9 (slow, best).");
717:
718: /* Send the request. */
719: packet_start(SSH_CMSG_REQUEST_COMPRESSION);
720: packet_put_int(options.compression_level);
721: packet_send();
722: packet_write_wait();
723: type = packet_read(&plen);
724: if (type == SSH_SMSG_SUCCESS)
725: packet_start_compression(options.compression_level);
726: else if (type == SSH_SMSG_FAILURE)
727: log("Warning: Remote host refused compression.");
728: else
729: packet_disconnect("Protocol error waiting for compression response.");
730: }
731: /* Allocate a pseudo tty if appropriate. */
732: if (tty_flag) {
733: debug("Requesting pty.");
734:
735: /* Start the packet. */
736: packet_start(SSH_CMSG_REQUEST_PTY);
737:
738: /* Store TERM in the packet. There is no limit on the
739: length of the string. */
740: cp = getenv("TERM");
741: if (!cp)
742: cp = "";
743: packet_put_string(cp, strlen(cp));
744:
745: /* Store window size in the packet. */
746: if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
747: memset(&ws, 0, sizeof(ws));
748: packet_put_int(ws.ws_row);
749: packet_put_int(ws.ws_col);
750: packet_put_int(ws.ws_xpixel);
751: packet_put_int(ws.ws_ypixel);
752:
753: /* Store tty modes in the packet. */
754: tty_make_modes(fileno(stdin));
755:
756: /* Send the packet, and wait for it to leave. */
757: packet_send();
758: packet_write_wait();
759:
760: /* Read response from the server. */
761: type = packet_read(&plen);
1.43 markus 762: if (type == SSH_SMSG_SUCCESS) {
1.31 markus 763: interactive = 1;
1.45 markus 764: have_tty = 1;
1.43 markus 765: } else if (type == SSH_SMSG_FAILURE)
1.31 markus 766: log("Warning: Remote host failed or refused to allocate a pseudo tty.");
767: else
768: packet_disconnect("Protocol error waiting for pty request response.");
769: }
770: /* Request X11 forwarding if enabled and DISPLAY is set. */
771: if (options.forward_x11 && getenv("DISPLAY") != NULL) {
1.50 markus 772: char proto[512], data[512];
773: /* Get reasonable local authentication information. */
774: x11_get_proto(proto, sizeof proto, data, sizeof data);
775: /* Request forwarding with authentication spoofing. */
1.31 markus 776: debug("Requesting X11 forwarding with authentication spoofing.");
1.50 markus 777: x11_request_forwarding_with_spoofing(0, proto, data);
1.31 markus 778:
779: /* Read response from the server. */
780: type = packet_read(&plen);
781: if (type == SSH_SMSG_SUCCESS) {
782: interactive = 1;
1.50 markus 783: } else if (type == SSH_SMSG_FAILURE) {
1.31 markus 784: log("Warning: Remote host denied X11 forwarding.");
1.50 markus 785: } else {
1.31 markus 786: packet_disconnect("Protocol error waiting for X11 forwarding");
1.50 markus 787: }
1.31 markus 788: }
789: /* Tell the packet module whether this is an interactive session. */
790: packet_set_interactive(interactive, options.keepalives);
791:
792: /* Clear agent forwarding if we don\'t have an agent. */
793: authfd = ssh_get_authentication_socket();
794: if (authfd < 0)
795: options.forward_agent = 0;
796: else
797: ssh_close_authentication_socket(authfd);
798:
799: /* Request authentication agent forwarding if appropriate. */
800: if (options.forward_agent) {
801: debug("Requesting authentication agent forwarding.");
802: auth_request_forwarding();
803:
804: /* Read response from the server. */
805: type = packet_read(&plen);
806: packet_integrity_check(plen, 0, type);
807: if (type != SSH_SMSG_SUCCESS)
808: log("Warning: Remote host denied authentication agent forwarding.");
809: }
810: /* Initiate local TCP/IP port forwardings. */
811: for (i = 0; i < options.num_local_forwards; i++) {
812: debug("Connections to local port %d forwarded to remote address %.200s:%d",
813: options.local_forwards[i].port,
814: options.local_forwards[i].host,
815: options.local_forwards[i].host_port);
816: channel_request_local_forwarding(options.local_forwards[i].port,
1.48 markus 817: options.local_forwards[i].host,
1.36 markus 818: options.local_forwards[i].host_port,
819: options.gateway_ports);
1.31 markus 820: }
821:
822: /* Initiate remote TCP/IP port forwardings. */
823: for (i = 0; i < options.num_remote_forwards; i++) {
824: debug("Connections to remote port %d forwarded to local address %.200s:%d",
825: options.remote_forwards[i].port,
826: options.remote_forwards[i].host,
827: options.remote_forwards[i].host_port);
828: channel_request_remote_forwarding(options.remote_forwards[i].port,
829: options.remote_forwards[i].host,
1.48 markus 830: options.remote_forwards[i].host_port);
1.31 markus 831: }
1.34 markus 832:
833: /* If requested, let ssh continue in the background. */
1.48 markus 834: if (fork_after_authentication_flag)
1.34 markus 835: if (daemon(1, 1) < 0)
836: fatal("daemon() failed: %.200s", strerror(errno));
1.31 markus 837:
1.33 markus 838: /*
839: * If a command was specified on the command line, execute the
840: * command now. Otherwise request the server to start a shell.
841: */
1.31 markus 842: if (buffer_len(&command) > 0) {
843: int len = buffer_len(&command);
844: if (len > 900)
845: len = 900;
846: debug("Sending command: %.*s", len, buffer_ptr(&command));
847: packet_start(SSH_CMSG_EXEC_CMD);
848: packet_put_string(buffer_ptr(&command), buffer_len(&command));
849: packet_send();
850: packet_write_wait();
851: } else {
852: debug("Requesting shell.");
853: packet_start(SSH_CMSG_EXEC_SHELL);
854: packet_send();
855: packet_write_wait();
856: }
857:
858: /* Enter the interactive session. */
1.45 markus 859: return client_loop(have_tty, tty_flag ? options.escape_char : -1);
860: }
861:
862: void
863: init_local_fwd(void)
864: {
865: int i;
866: /* Initiate local TCP/IP port forwardings. */
867: for (i = 0; i < options.num_local_forwards; i++) {
868: debug("Connections to local port %d forwarded to remote address %.200s:%d",
869: options.local_forwards[i].port,
870: options.local_forwards[i].host,
871: options.local_forwards[i].host_port);
872: channel_request_local_forwarding(options.local_forwards[i].port,
1.48 markus 873: options.local_forwards[i].host,
1.45 markus 874: options.local_forwards[i].host_port,
875: options.gateway_ports);
876: }
877: }
878:
879: extern void client_set_session_ident(int id);
880:
881: void
882: client_init(int id, void *arg)
883: {
884: int len;
885: debug("client_init id %d arg %d", id, (int)arg);
1.31 markus 886:
1.45 markus 887: if (no_shell_flag)
888: goto done;
889:
890: if (tty_flag) {
891: struct winsize ws;
892: char *cp;
893: cp = getenv("TERM");
894: if (!cp)
895: cp = "";
896: /* Store window size in the packet. */
897: if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
898: memset(&ws, 0, sizeof(ws));
899:
900: channel_request_start(id, "pty-req", 0);
901: packet_put_cstring(cp);
902: packet_put_int(ws.ws_col);
903: packet_put_int(ws.ws_row);
904: packet_put_int(ws.ws_xpixel);
905: packet_put_int(ws.ws_ypixel);
906: packet_put_cstring(""); /* XXX: encode terminal modes */
907: packet_send();
908: /* XXX wait for reply */
909: }
1.50 markus 910: if (options.forward_x11 &&
911: getenv("DISPLAY") != NULL) {
912: char proto[512], data[512];
913: /* Get reasonable local authentication information. */
914: x11_get_proto(proto, sizeof proto, data, sizeof data);
915: /* Request forwarding with authentication spoofing. */
916: debug("Requesting X11 forwarding with authentication spoofing.");
917: x11_request_forwarding_with_spoofing(id, proto, data);
918: /* XXX wait for reply */
919: }
920:
1.45 markus 921: len = buffer_len(&command);
922: if (len > 0) {
923: if (len > 900)
924: len = 900;
925: debug("Sending command: %.*s", len, buffer_ptr(&command));
926: channel_request_start(id, "exec", 0);
927: packet_put_string(buffer_ptr(&command), len);
928: packet_send();
929: } else {
930: channel_request(id, "shell", 0);
931: }
932: /* channel_callback(id, SSH2_MSG_OPEN_CONFIGMATION, client_init, 0); */
933: done:
934: /* register different callback, etc. XXX */
935: client_set_session_ident(id);
936: }
937:
938: int
939: ssh_session2(void)
940: {
941: int window, packetmax, id;
942: int in = dup(STDIN_FILENO);
943: int out = dup(STDOUT_FILENO);
944: int err = dup(STDERR_FILENO);
945:
946: if (in < 0 || out < 0 || err < 0)
947: fatal("dump in/out/err failed");
948:
949: /* should be pre-session */
950: init_local_fwd();
951:
952: window = 32*1024;
953: if (tty_flag) {
954: packetmax = window/8;
955: } else {
956: window *= 2;
957: packetmax = window/2;
958: }
959:
960: id = channel_new(
961: "session", SSH_CHANNEL_OPENING, in, out, err,
962: window, packetmax, CHAN_EXTENDED_WRITE, xstrdup("client-session"));
963:
964:
965: channel_open(id);
966: channel_register_callback(id, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, client_init, (void *)0);
1.31 markus 967:
1.45 markus 968: return client_loop(tty_flag, tty_flag ? options.escape_char : -1);
1.1 deraadt 969: }
![[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