Annotation of src/usr.bin/ssh/ssh.c, Revision 1.98
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: * Ssh client program. This program can be used to log into a remote machine.
6: * The software supports strong authentication, encryption, and forwarding
7: * of X11, TCP/IP, and authentication connections.
8: *
1.64 deraadt 9: * As far as I am concerned, the code I have written for this software
10: * can be used freely for any purpose. Any derived versions of this
11: * software must be clearly marked as such, and if the derived work is
12: * incompatible with the protocol description in the RFC file, it must be
13: * called by a name other than "ssh" or "Secure Shell".
14: *
15: * Copyright (c) 1999 Niels Provos. All rights reserved.
16: *
17: * Modified to work with SSL by Niels Provos <provos@citi.umich.edu>
18: * in Canada (German citizen).
19: *
20: * Redistribution and use in source and binary forms, with or without
21: * modification, are permitted provided that the following conditions
22: * are met:
23: * 1. Redistributions of source code must retain the above copyright
24: * notice, this list of conditions and the following disclaimer.
25: * 2. Redistributions in binary form must reproduce the above copyright
26: * notice, this list of conditions and the following disclaimer in the
27: * documentation and/or other materials provided with the distribution.
28: *
29: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
30: * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
31: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
32: * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
33: * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
34: * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
35: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
36: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
37: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
38: * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1.32 deraadt 39: */
1.1 deraadt 40:
41: #include "includes.h"
1.98 ! markus 42: RCSID("$OpenBSD: ssh.c,v 1.97 2001/02/21 21:14:04 stevesk Exp $");
1.49 markus 43:
44: #include <openssl/evp.h>
1.72 markus 45: #include <openssl/err.h>
1.1 deraadt 46:
1.84 markus 47: #include "ssh.h"
48: #include "ssh1.h"
49: #include "ssh2.h"
50: #include "compat.h"
51: #include "cipher.h"
1.1 deraadt 52: #include "xmalloc.h"
53: #include "packet.h"
54: #include "buffer.h"
55: #include "uidswap.h"
1.44 markus 56: #include "channels.h"
1.49 markus 57: #include "key.h"
1.58 markus 58: #include "authfd.h"
1.49 markus 59: #include "authfile.h"
1.83 markus 60: #include "pathnames.h"
1.81 markus 61: #include "clientloop.h"
1.84 markus 62: #include "log.h"
63: #include "readconf.h"
64: #include "sshconnect.h"
65: #include "tildexpand.h"
1.89 markus 66: #include "dispatch.h"
1.84 markus 67: #include "misc.h"
1.95 markus 68: #include "kex.h"
69: #include "mac.h"
1.49 markus 70:
71: extern char *__progname;
1.1 deraadt 72:
1.37 markus 73: /* Flag indicating whether IPv4 or IPv6. This can be set on the command line.
74: Default value is AF_UNSPEC means both IPv4 and IPv6. */
75: int IPv4or6 = AF_UNSPEC;
76:
1.31 markus 77: /* Flag indicating whether debug mode is on. This can be set on the command line. */
1.1 deraadt 78: int debug_flag = 0;
79:
1.46 markus 80: /* Flag indicating whether a tty should be allocated */
1.1 deraadt 81: int tty_flag = 0;
1.79 markus 82: int no_tty_flag = 0;
83: int force_tty_flag = 0;
1.1 deraadt 84:
1.45 markus 85: /* don't exec a shell */
86: int no_shell_flag = 0;
87:
1.33 markus 88: /*
89: * Flag indicating that nothing should be read from stdin. This can be set
90: * on the command line.
91: */
1.1 deraadt 92: int stdin_null_flag = 0;
93:
1.33 markus 94: /*
95: * Flag indicating that ssh should fork after authentication. This is useful
96: * so that the pasphrase can be entered manually, and then ssh goes to the
97: * background.
98: */
1.1 deraadt 99: int fork_after_authentication_flag = 0;
100:
1.33 markus 101: /*
102: * General data structure for command line options and options configurable
103: * in configuration files. See readconf.h.
104: */
1.1 deraadt 105: Options options;
106:
1.33 markus 107: /*
108: * Name of the host we are connecting to. This is the name given on the
109: * command line, or the HostName specified for the user-supplied name in a
110: * configuration file.
111: */
1.1 deraadt 112: char *host;
113:
1.22 provos 114: /* socket address the host resolves to */
1.37 markus 115: struct sockaddr_storage hostaddr;
1.22 provos 116:
1.33 markus 117: /*
118: * Flag to indicate that we have received a window change signal which has
119: * not yet been processed. This will cause a message indicating the new
120: * window size to be sent to the server a little later. This is volatile
121: * because this is updated in a signal handler.
122: */
1.1 deraadt 123: volatile int received_window_change_signal = 0;
124:
125: /* Flag indicating whether we have a valid host private key loaded. */
126: int host_private_key_loaded = 0;
127:
128: /* Host private key. */
1.2 provos 129: RSA *host_private_key = NULL;
1.1 deraadt 130:
1.10 dugsong 131: /* Original real UID. */
132: uid_t original_real_uid;
1.1 deraadt 133:
1.45 markus 134: /* command to be executed */
135: Buffer command;
136:
1.85 djm 137: /* Should we execute a command or invoke a subsystem? */
138: int subsystem_flag = 0;
139:
1.1 deraadt 140: /* Prints a help message to the user. This function never returns. */
141:
1.2 provos 142: void
1.93 itojun 143: usage(void)
1.1 deraadt 144: {
1.76 markus 145: fprintf(stderr, "Usage: %s [options] host [command]\n", __progname);
1.31 markus 146: fprintf(stderr, "Options:\n");
147: fprintf(stderr, " -l user Log in using this user name.\n");
1.93 itojun 148: fprintf(stderr, " -n Redirect input from " _PATH_DEVNULL ".\n");
1.53 markus 149: fprintf(stderr, " -A Enable authentication agent forwarding.\n");
1.31 markus 150: fprintf(stderr, " -a Disable authentication agent forwarding.\n");
1.9 dugsong 151: #ifdef AFS
1.31 markus 152: fprintf(stderr, " -k Disable Kerberos ticket and AFS token forwarding.\n");
153: #endif /* AFS */
1.88 stevesk 154: fprintf(stderr, " -X Enable X11 connection forwarding.\n");
1.31 markus 155: fprintf(stderr, " -x Disable X11 connection forwarding.\n");
1.97 stevesk 156: fprintf(stderr, " -i file Identity for public key authentication\n");
157: fprintf(stderr, " (default: ~/.ssh/identity).\n");
1.31 markus 158: fprintf(stderr, " -t Tty; allocate a tty even if command is given.\n");
1.45 markus 159: fprintf(stderr, " -T Do not allocate a tty.\n");
1.31 markus 160: fprintf(stderr, " -v Verbose; display verbose debugging messages.\n");
1.66 markus 161: fprintf(stderr, " Multiple -v increases verbosity.\n");
1.31 markus 162: fprintf(stderr, " -V Display version number only.\n");
163: fprintf(stderr, " -P Don't allocate a privileged port.\n");
164: fprintf(stderr, " -q Quiet; don't display any warning messages.\n");
165: fprintf(stderr, " -f Fork into background after authentication.\n");
166: fprintf(stderr, " -e char Set escape character; ``none'' = disable (default: ~).\n");
167:
168: fprintf(stderr, " -c cipher Select encryption algorithm: "
169: "``3des'', "
170: "``blowfish''\n");
171: fprintf(stderr, " -p port Connect to this port. Server must be on the same port.\n");
172: fprintf(stderr, " -L listen-port:host:port Forward local port to remote address\n");
173: fprintf(stderr, " -R listen-port:host:port Forward remote port to local address\n");
1.76 markus 174: fprintf(stderr, " These cause %s to listen for connections on a port, and\n", __progname);
1.31 markus 175: fprintf(stderr, " forward them to the other side by connecting to host:port.\n");
176: fprintf(stderr, " -C Enable compression.\n");
1.45 markus 177: fprintf(stderr, " -N Do not execute a shell or command.\n");
1.31 markus 178: fprintf(stderr, " -g Allow remote hosts to connect to forwarded ports.\n");
1.92 jakob 179: fprintf(stderr, " -1 Force protocol version 1.\n");
180: fprintf(stderr, " -2 Force protocol version 2.\n");
1.37 markus 181: fprintf(stderr, " -4 Use IPv4 only.\n");
182: fprintf(stderr, " -6 Use IPv6 only.\n");
1.31 markus 183: fprintf(stderr, " -o 'option' Process the option as if it was read from a configuration file.\n");
1.85 djm 184: fprintf(stderr, " -s Invoke command (mandatory) as SSH2 subsystem.\n");
1.31 markus 185: exit(1);
1.1 deraadt 186: }
187:
1.32 deraadt 188: /*
189: * Connects to the given host using rsh (or prints an error message and exits
190: * if rsh is not available). This function never returns.
191: */
1.2 provos 192: void
1.31 markus 193: rsh_connect(char *host, char *user, Buffer * command)
1.1 deraadt 194: {
1.31 markus 195: char *args[10];
196: int i;
197:
198: log("Using rsh. WARNING: Connection will not be encrypted.");
199: /* Build argument list for rsh. */
200: i = 0;
201: args[i++] = _PATH_RSH;
202: /* host may have to come after user on some systems */
203: args[i++] = host;
204: if (user) {
205: args[i++] = "-l";
206: args[i++] = user;
207: }
208: if (buffer_len(command) > 0) {
209: buffer_append(command, "\0", 1);
210: args[i++] = buffer_ptr(command);
211: }
212: args[i++] = NULL;
213: if (debug_flag) {
214: for (i = 0; args[i]; i++) {
215: if (i != 0)
216: fprintf(stderr, " ");
217: fprintf(stderr, "%s", args[i]);
218: }
219: fprintf(stderr, "\n");
220: }
221: execv(_PATH_RSH, args);
222: perror(_PATH_RSH);
223: exit(1);
1.1 deraadt 224: }
225:
1.72 markus 226: int ssh_session(void);
227: int ssh_session2(void);
228: int guess_identity_file_type(const char *filename);
1.45 markus 229:
1.32 deraadt 230: /*
231: * Main program for the ssh client.
232: */
1.2 provos 233: int
234: main(int ac, char **av)
1.1 deraadt 235: {
1.45 markus 236: int i, opt, optind, exit_status, ok;
1.35 markus 237: u_short fwd_port, fwd_host_port;
1.31 markus 238: char *optarg, *cp, buf[256];
239: struct stat st;
1.98 ! markus 240: struct passwd *pw;
1.45 markus 241: int dummy;
1.31 markus 242: uid_t original_effective_uid;
243:
1.33 markus 244: /*
245: * Save the original real uid. It will be needed later (uid-swapping
246: * may clobber the real uid).
247: */
1.31 markus 248: original_real_uid = getuid();
249: original_effective_uid = geteuid();
250:
251: /* If we are installed setuid root be careful to not drop core. */
252: if (original_real_uid != original_effective_uid) {
253: struct rlimit rlim;
254: rlim.rlim_cur = rlim.rlim_max = 0;
255: if (setrlimit(RLIMIT_CORE, &rlim) < 0)
256: fatal("setrlimit failed: %.100s", strerror(errno));
1.1 deraadt 257: }
1.33 markus 258: /*
259: * Use uid-swapping to give up root privileges for the duration of
260: * option processing. We will re-instantiate the rights when we are
261: * ready to create the privileged port, and will permanently drop
262: * them when the port has been created (actually, when the connection
263: * has been made, as we may need to create the port several times).
264: */
1.31 markus 265: temporarily_use_uid(original_real_uid);
266:
1.33 markus 267: /*
268: * Set our umask to something reasonable, as some files are created
269: * with the default umask. This will make them world-readable but
270: * writable only by the owner, which is ok for all files for which we
271: * don't set the modes explicitly.
272: */
1.31 markus 273: umask(022);
274:
275: /* Initialize option structure to indicate that no values have been set. */
276: initialize_options(&options);
277:
278: /* Parse command-line arguments. */
279: host = NULL;
280:
281: for (optind = 1; optind < ac; optind++) {
282: if (av[optind][0] != '-') {
283: if (host)
284: break;
285: if ((cp = strchr(av[optind], '@'))) {
1.48 markus 286: if(cp == av[optind])
287: usage();
1.31 markus 288: options.user = av[optind];
289: *cp = '\0';
290: host = ++cp;
291: } else
292: host = av[optind];
293: continue;
294: }
295: opt = av[optind][1];
296: if (!opt)
297: usage();
1.95 markus 298: if (strchr("eilcmpLRo", opt)) { /* options with arguments */
1.31 markus 299: optarg = av[optind] + 2;
300: if (strcmp(optarg, "") == 0) {
301: if (optind >= ac - 1)
302: usage();
303: optarg = av[++optind];
304: }
305: } else {
306: if (av[optind][2])
307: usage();
308: optarg = NULL;
309: }
310: switch (opt) {
1.91 jakob 311: case '1':
312: options.protocol = SSH_PROTO_1;
313: break;
1.47 markus 314: case '2':
315: options.protocol = SSH_PROTO_2;
316: break;
1.37 markus 317: case '4':
318: IPv4or6 = AF_INET;
319: break;
320: case '6':
321: IPv4or6 = AF_INET6;
322: break;
1.31 markus 323: case 'n':
324: stdin_null_flag = 1;
325: break;
326: case 'f':
327: fork_after_authentication_flag = 1;
328: stdin_null_flag = 1;
329: break;
330: case 'x':
331: options.forward_x11 = 0;
332: break;
333: case 'X':
334: options.forward_x11 = 1;
335: break;
336: case 'g':
337: options.gateway_ports = 1;
338: break;
339: case 'P':
340: options.use_privileged_port = 0;
341: break;
342: case 'a':
343: options.forward_agent = 0;
1.53 markus 344: break;
345: case 'A':
346: options.forward_agent = 1;
1.31 markus 347: break;
1.9 dugsong 348: #ifdef AFS
1.31 markus 349: case 'k':
350: options.kerberos_tgt_passing = 0;
351: options.afs_token_passing = 0;
352: break;
1.1 deraadt 353: #endif
1.31 markus 354: case 'i':
355: if (stat(optarg, &st) < 0) {
356: fprintf(stderr, "Warning: Identity file %s does not exist.\n",
1.72 markus 357: optarg);
1.31 markus 358: break;
359: }
360: if (options.num_identity_files >= SSH_MAX_IDENTITY_FILES)
361: fatal("Too many identity files specified (max %d)",
1.72 markus 362: SSH_MAX_IDENTITY_FILES);
363: options.identity_files[options.num_identity_files++] = xstrdup(optarg);
1.31 markus 364: break;
365: case 't':
1.79 markus 366: if (tty_flag)
367: force_tty_flag = 1;
1.31 markus 368: tty_flag = 1;
369: break;
370: case 'v':
1.66 markus 371: if (0 == debug_flag) {
372: debug_flag = 1;
373: options.log_level = SYSLOG_LEVEL_DEBUG1;
374: } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) {
375: options.log_level++;
376: break;
377: } else {
378: fatal("Too high debugging level.\n");
379: }
380: /* fallthrough */
1.31 markus 381: case 'V':
1.96 deraadt 382: fprintf(stderr,
383: "%s, SSH protocols %d.%d/%d.%d, OpenSSL 0x%8.8lx\n",
1.46 markus 384: SSH_VERSION,
385: PROTOCOL_MAJOR_1, PROTOCOL_MINOR_1,
1.96 deraadt 386: PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2,
387: SSLeay());
1.31 markus 388: if (opt == 'V')
389: exit(0);
390: break;
391: case 'q':
392: options.log_level = SYSLOG_LEVEL_QUIET;
393: break;
394: case 'e':
395: if (optarg[0] == '^' && optarg[2] == 0 &&
1.78 markus 396: (u_char) optarg[1] >= 64 && (u_char) optarg[1] < 128)
397: options.escape_char = (u_char) optarg[1] & 31;
1.31 markus 398: else if (strlen(optarg) == 1)
1.78 markus 399: options.escape_char = (u_char) optarg[0];
1.31 markus 400: else if (strcmp(optarg, "none") == 0)
401: options.escape_char = -2;
402: else {
403: fprintf(stderr, "Bad escape character '%s'.\n", optarg);
404: exit(1);
405: }
406: break;
407: case 'c':
1.49 markus 408: if (ciphers_valid(optarg)) {
409: /* SSH2 only */
410: options.ciphers = xstrdup(optarg);
1.51 markus 411: options.cipher = SSH_CIPHER_ILLEGAL;
1.49 markus 412: } else {
413: /* SSH1 only */
1.74 markus 414: options.cipher = cipher_number(optarg);
415: if (options.cipher == -1) {
1.49 markus 416: fprintf(stderr, "Unknown cipher type '%s'\n", optarg);
417: exit(1);
418: }
1.74 markus 419: if (options.cipher == SSH_CIPHER_3DES) {
420: options.ciphers = "3des-cbc";
421: } else if (options.cipher == SSH_CIPHER_BLOWFISH) {
422: options.ciphers = "blowfish-cbc";
423: } else {
424: options.ciphers = (char *)-1;
425: }
1.95 markus 426: }
427: break;
428: case 'm':
429: if (mac_valid(optarg))
430: options.macs = xstrdup(optarg);
431: else {
432: fprintf(stderr, "Unknown mac type '%s'\n", optarg);
433: exit(1);
1.31 markus 434: }
435: break;
436: case 'p':
437: options.port = atoi(optarg);
438: break;
439: case 'l':
440: options.user = optarg;
441: break;
442: case 'R':
1.37 markus 443: if (sscanf(optarg, "%hu/%255[^/]/%hu", &fwd_port, buf,
444: &fwd_host_port) != 3 &&
445: sscanf(optarg, "%hu:%255[^:]:%hu", &fwd_port, buf,
446: &fwd_host_port) != 3) {
1.31 markus 447: fprintf(stderr, "Bad forwarding specification '%s'.\n", optarg);
448: usage();
449: /* NOTREACHED */
450: }
451: add_remote_forward(&options, fwd_port, buf, fwd_host_port);
452: break;
453: case 'L':
1.37 markus 454: if (sscanf(optarg, "%hu/%255[^/]/%hu", &fwd_port, buf,
455: &fwd_host_port) != 3 &&
456: sscanf(optarg, "%hu:%255[^:]:%hu", &fwd_port, buf,
457: &fwd_host_port) != 3) {
1.31 markus 458: fprintf(stderr, "Bad forwarding specification '%s'.\n", optarg);
459: usage();
460: /* NOTREACHED */
461: }
462: add_local_forward(&options, fwd_port, buf, fwd_host_port);
463: break;
464: case 'C':
465: options.compression = 1;
466: break;
1.45 markus 467: case 'N':
468: no_shell_flag = 1;
469: no_tty_flag = 1;
470: break;
471: case 'T':
472: no_tty_flag = 1;
473: break;
1.31 markus 474: case 'o':
475: dummy = 1;
476: if (process_config_line(&options, host ? host : "", optarg,
477: "command-line", 0, &dummy) != 0)
478: exit(1);
479: break;
1.85 djm 480: case 's':
481: subsystem_flag = 1;
482: break;
1.31 markus 483: default:
484: usage();
1.1 deraadt 485: }
1.31 markus 486: }
487:
488: /* Check that we got a host name. */
489: if (!host)
490: usage();
491:
1.54 markus 492: SSLeay_add_all_algorithms();
1.72 markus 493: ERR_load_crypto_strings();
1.31 markus 494:
495: /* Initialize the command to execute on remote host. */
496: buffer_init(&command);
1.1 deraadt 497:
1.33 markus 498: /*
499: * Save the command to execute on the remote host in a buffer. There
500: * is no limit on the length of the command, except by the maximum
501: * packet size. Also sets the tty flag if there is no command.
502: */
1.31 markus 503: if (optind == ac) {
504: /* No command specified - execute shell on a tty. */
505: tty_flag = 1;
1.85 djm 506: if (subsystem_flag) {
507: fprintf(stderr, "You must specify a subsystem to invoke.");
508: usage();
509: }
1.31 markus 510: } else {
511: /* A command has been specified. Store it into the
512: buffer. */
513: for (i = optind; i < ac; i++) {
514: if (i > optind)
515: buffer_append(&command, " ", 1);
516: buffer_append(&command, av[i], strlen(av[i]));
517: }
518: }
519:
520: /* Cannot fork to background if no command. */
1.63 markus 521: if (fork_after_authentication_flag && buffer_len(&command) == 0 && !no_shell_flag)
1.31 markus 522: fatal("Cannot fork into background without a command to execute.");
523:
524: /* Allocate a tty by default if no command specified. */
525: if (buffer_len(&command) == 0)
526: tty_flag = 1;
527:
1.75 markus 528: /* Force no tty*/
529: if (no_tty_flag)
530: tty_flag = 0;
1.31 markus 531: /* Do not allocate a tty if stdin is not a tty. */
1.79 markus 532: if (!isatty(fileno(stdin)) && !force_tty_flag) {
1.31 markus 533: if (tty_flag)
1.82 markus 534: log("Pseudo-terminal will not be allocated because stdin is not a terminal.\n");
1.31 markus 535: tty_flag = 0;
536: }
1.45 markus 537:
1.31 markus 538: /* Get user data. */
539: pw = getpwuid(original_real_uid);
540: if (!pw) {
1.82 markus 541: log("You don't exist, go away!\n");
1.31 markus 542: exit(1);
543: }
544: /* Take a copy of the returned structure. */
1.98 ! markus 545: pw = pwcopy(pw);
1.31 markus 546:
547: /* Initialize "log" output. Since we are the client all output
548: actually goes to the terminal. */
549: log_init(av[0], options.log_level, SYSLOG_FACILITY_USER, 0);
550:
551: /* Read per-user configuration file. */
1.83 markus 552: snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir, _PATH_SSH_USER_CONFFILE);
1.31 markus 553: read_config_file(buf, host, &options);
554:
555: /* Read systemwide configuration file. */
1.83 markus 556: read_config_file(_PATH_HOST_CONFIG_FILE, host, &options);
1.31 markus 557:
558: /* Fill configuration defaults. */
559: fill_default_options(&options);
560:
561: /* reinit */
562: log_init(av[0], options.log_level, SYSLOG_FACILITY_USER, 0);
563:
564: if (options.user == NULL)
565: options.user = xstrdup(pw->pw_name);
566:
567: if (options.hostname != NULL)
568: host = options.hostname;
569:
570: /* Disable rhosts authentication if not running as root. */
571: if (original_effective_uid != 0 || !options.use_privileged_port) {
1.77 markus 572: debug("Rhosts Authentication disabled, "
1.71 markus 573: "originating port will not be trusted.");
1.31 markus 574: options.rhosts_authentication = 0;
575: }
1.33 markus 576: /*
577: * If using rsh has been selected, exec it now (without trying
578: * anything else). Note that we must release privileges first.
579: */
1.31 markus 580: if (options.use_rsh) {
1.33 markus 581: /*
582: * Restore our superuser privileges. This must be done
583: * before permanently setting the uid.
584: */
1.31 markus 585: restore_uid();
586:
587: /* Switch to the original uid permanently. */
588: permanently_set_uid(original_real_uid);
589:
590: /* Execute rsh. */
591: rsh_connect(host, options.user, &command);
592: fatal("rsh_connect returned");
593: }
594: /* Restore our superuser privileges. */
595: restore_uid();
596:
1.77 markus 597: /* Open a connection to the remote host. */
1.31 markus 598:
599: ok = ssh_connect(host, &hostaddr, options.port,
1.77 markus 600: options.connection_attempts,
601: original_effective_uid != 0 || !options.use_privileged_port,
602: original_real_uid,
603: options.proxy_command);
1.31 markus 604:
1.33 markus 605: /*
606: * If we successfully made the connection, load the host private key
607: * in case we will need it later for combined rsa-rhosts
608: * authentication. This must be done before releasing extra
609: * privileges, because the file is only readable by root.
610: */
1.49 markus 611: if (ok && (options.protocol & SSH_PROTO_1)) {
612: Key k;
1.31 markus 613: host_private_key = RSA_new();
1.72 markus 614: k.type = KEY_RSA1;
1.49 markus 615: k.rsa = host_private_key;
1.83 markus 616: if (load_private_key(_PATH_HOST_KEY_FILE, "", &k, NULL))
1.31 markus 617: host_private_key_loaded = 1;
618: }
1.33 markus 619: /*
620: * Get rid of any extra privileges that we may have. We will no
621: * longer need them. Also, extra privileges could make it very hard
622: * to read identity files and other non-world-readable files from the
623: * user's home directory if it happens to be on a NFS volume where
624: * root is mapped to nobody.
625: */
626:
627: /*
628: * Note that some legacy systems need to postpone the following call
629: * to permanently_set_uid() until the private hostkey is destroyed
630: * with RSA_free(). Otherwise the calling user could ptrace() the
631: * process, read the private hostkey and impersonate the host.
632: * OpenBSD does not allow ptracing of setuid processes.
633: */
1.31 markus 634: permanently_set_uid(original_real_uid);
635:
1.33 markus 636: /*
637: * Now that we are back to our own permissions, create ~/.ssh
638: * directory if it doesn\'t already exist.
639: */
1.83 markus 640: snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir, _PATH_SSH_USER_DIR);
1.31 markus 641: if (stat(buf, &st) < 0)
1.57 djm 642: if (mkdir(buf, 0700) < 0)
1.31 markus 643: error("Could not create directory '%.200s'.", buf);
644:
645: /* Check if the connection failed, and try "rsh" if appropriate. */
646: if (!ok) {
647: if (options.port != 0)
1.35 markus 648: log("Secure connection to %.100s on port %hu refused%.100s.",
1.31 markus 649: host, options.port,
650: options.fallback_to_rsh ? "; reverting to insecure method" : "");
651: else
652: log("Secure connection to %.100s refused%.100s.", host,
653: options.fallback_to_rsh ? "; reverting to insecure method" : "");
654:
655: if (options.fallback_to_rsh) {
656: rsh_connect(host, options.user, &command);
657: fatal("rsh_connect returned");
658: }
659: exit(1);
660: }
1.72 markus 661: /* Expand ~ in options.identity_files, known host file names. */
1.49 markus 662: /* XXX mem-leaks */
1.72 markus 663: for (i = 0; i < options.num_identity_files; i++) {
1.31 markus 664: options.identity_files[i] =
1.72 markus 665: tilde_expand_filename(options.identity_files[i], original_real_uid);
666: options.identity_files_type[i] = guess_identity_file_type(options.identity_files[i]);
667: debug("identity file %s type %d", options.identity_files[i],
668: options.identity_files_type[i]);
669: }
670: options.system_hostfile =
671: tilde_expand_filename(options.system_hostfile, original_real_uid);
672: options.user_hostfile =
673: tilde_expand_filename(options.user_hostfile, original_real_uid);
674: options.system_hostfile2 =
675: tilde_expand_filename(options.system_hostfile2, original_real_uid);
676: options.user_hostfile2 =
677: tilde_expand_filename(options.user_hostfile2, original_real_uid);
1.31 markus 678:
679: /* Log into the remote system. This never returns if the login fails. */
680: ssh_login(host_private_key_loaded, host_private_key,
1.37 markus 681: host, (struct sockaddr *)&hostaddr, original_real_uid);
1.31 markus 682:
683: /* We no longer need the host private key. Clear it now. */
684: if (host_private_key_loaded)
685: RSA_free(host_private_key); /* Destroys contents safely */
686:
1.45 markus 687: exit_status = compat20 ? ssh_session2() : ssh_session();
688: packet_close();
689: return exit_status;
690: }
691:
1.50 markus 692: void
693: x11_get_proto(char *proto, int proto_len, char *data, int data_len)
694: {
695: char line[512];
696: FILE *f;
697: int got_data = 0, i;
698:
1.55 markus 699: if (options.xauth_location) {
700: /* Try to get Xauthority information for the display. */
1.93 itojun 701: snprintf(line, sizeof line, "%.100s list %.200s 2>" _PATH_DEVNULL,
1.55 markus 702: options.xauth_location, getenv("DISPLAY"));
703: f = popen(line, "r");
704: if (f && fgets(line, sizeof(line), f) &&
705: sscanf(line, "%*s %s %s", proto, data) == 2)
706: got_data = 1;
707: if (f)
708: pclose(f);
709: }
1.50 markus 710: /*
711: * If we didn't get authentication data, just make up some
712: * data. The forwarding code will check the validity of the
713: * response anyway, and substitute this data. The X11
714: * server, however, will ignore this fake data and use
715: * whatever authentication mechanisms it was using otherwise
716: * for the local connection.
717: */
718: if (!got_data) {
719: u_int32_t rand = 0;
720:
721: strlcpy(proto, "MIT-MAGIC-COOKIE-1", proto_len);
722: for (i = 0; i < 16; i++) {
723: if (i % 4 == 0)
724: rand = arc4random();
725: snprintf(data + 2 * i, data_len - 2 * i, "%02x", rand & 0xff);
726: rand >>= 8;
727: }
728: }
729: }
730:
1.70 markus 731: void
732: ssh_init_forwarding(void)
733: {
1.86 markus 734: int success = 0;
1.70 markus 735: int i;
1.86 markus 736:
1.70 markus 737: /* Initiate local TCP/IP port forwardings. */
738: for (i = 0; i < options.num_local_forwards; i++) {
739: debug("Connections to local port %d forwarded to remote address %.200s:%d",
740: options.local_forwards[i].port,
741: options.local_forwards[i].host,
742: options.local_forwards[i].host_port);
1.86 markus 743: success += channel_request_local_forwarding(
1.70 markus 744: options.local_forwards[i].port,
745: options.local_forwards[i].host,
746: options.local_forwards[i].host_port,
747: options.gateway_ports);
748: }
1.86 markus 749: if (i > 0 && success == 0)
750: error("Could not request local forwarding.");
1.70 markus 751:
752: /* Initiate remote TCP/IP port forwardings. */
753: for (i = 0; i < options.num_remote_forwards; i++) {
754: debug("Connections to remote port %d forwarded to local address %.200s:%d",
755: options.remote_forwards[i].port,
756: options.remote_forwards[i].host,
757: options.remote_forwards[i].host_port);
758: channel_request_remote_forwarding(
759: options.remote_forwards[i].port,
760: options.remote_forwards[i].host,
761: options.remote_forwards[i].host_port);
762: }
763: }
764:
765: void
766: check_agent_present(void)
767: {
768: if (options.forward_agent) {
769: /* Clear agent forwarding if we don\'t have an agent. */
770: int authfd = ssh_get_authentication_socket();
771: if (authfd < 0)
772: options.forward_agent = 0;
773: else
774: ssh_close_authentication_socket(authfd);
775: }
776: }
777:
1.45 markus 778: int
779: ssh_session(void)
780: {
781: int type;
782: int plen;
783: int interactive = 0;
784: int have_tty = 0;
785: struct winsize ws;
786: char *cp;
787:
1.31 markus 788: /* Enable compression if requested. */
789: if (options.compression) {
790: debug("Requesting compression at level %d.", options.compression_level);
791:
792: if (options.compression_level < 1 || options.compression_level > 9)
793: fatal("Compression level must be from 1 (fast) to 9 (slow, best).");
794:
795: /* Send the request. */
796: packet_start(SSH_CMSG_REQUEST_COMPRESSION);
797: packet_put_int(options.compression_level);
798: packet_send();
799: packet_write_wait();
800: type = packet_read(&plen);
801: if (type == SSH_SMSG_SUCCESS)
802: packet_start_compression(options.compression_level);
803: else if (type == SSH_SMSG_FAILURE)
804: log("Warning: Remote host refused compression.");
805: else
806: packet_disconnect("Protocol error waiting for compression response.");
807: }
808: /* Allocate a pseudo tty if appropriate. */
809: if (tty_flag) {
810: debug("Requesting pty.");
811:
812: /* Start the packet. */
813: packet_start(SSH_CMSG_REQUEST_PTY);
814:
815: /* Store TERM in the packet. There is no limit on the
816: length of the string. */
817: cp = getenv("TERM");
818: if (!cp)
819: cp = "";
820: packet_put_string(cp, strlen(cp));
821:
822: /* Store window size in the packet. */
823: if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
824: memset(&ws, 0, sizeof(ws));
825: packet_put_int(ws.ws_row);
826: packet_put_int(ws.ws_col);
827: packet_put_int(ws.ws_xpixel);
828: packet_put_int(ws.ws_ypixel);
829:
830: /* Store tty modes in the packet. */
831: tty_make_modes(fileno(stdin));
832:
833: /* Send the packet, and wait for it to leave. */
834: packet_send();
835: packet_write_wait();
836:
837: /* Read response from the server. */
838: type = packet_read(&plen);
1.43 markus 839: if (type == SSH_SMSG_SUCCESS) {
1.31 markus 840: interactive = 1;
1.45 markus 841: have_tty = 1;
1.43 markus 842: } else if (type == SSH_SMSG_FAILURE)
1.31 markus 843: log("Warning: Remote host failed or refused to allocate a pseudo tty.");
844: else
845: packet_disconnect("Protocol error waiting for pty request response.");
846: }
847: /* Request X11 forwarding if enabled and DISPLAY is set. */
848: if (options.forward_x11 && getenv("DISPLAY") != NULL) {
1.50 markus 849: char proto[512], data[512];
850: /* Get reasonable local authentication information. */
851: x11_get_proto(proto, sizeof proto, data, sizeof data);
852: /* Request forwarding with authentication spoofing. */
1.31 markus 853: debug("Requesting X11 forwarding with authentication spoofing.");
1.50 markus 854: x11_request_forwarding_with_spoofing(0, proto, data);
1.31 markus 855:
856: /* Read response from the server. */
857: type = packet_read(&plen);
858: if (type == SSH_SMSG_SUCCESS) {
859: interactive = 1;
1.50 markus 860: } else if (type == SSH_SMSG_FAILURE) {
1.31 markus 861: log("Warning: Remote host denied X11 forwarding.");
1.50 markus 862: } else {
1.31 markus 863: packet_disconnect("Protocol error waiting for X11 forwarding");
1.50 markus 864: }
1.31 markus 865: }
866: /* Tell the packet module whether this is an interactive session. */
1.80 markus 867: packet_set_interactive(interactive);
1.31 markus 868:
869: /* Request authentication agent forwarding if appropriate. */
1.70 markus 870: check_agent_present();
871:
1.31 markus 872: if (options.forward_agent) {
873: debug("Requesting authentication agent forwarding.");
874: auth_request_forwarding();
875:
876: /* Read response from the server. */
877: type = packet_read(&plen);
878: packet_integrity_check(plen, 0, type);
879: if (type != SSH_SMSG_SUCCESS)
880: log("Warning: Remote host denied authentication agent forwarding.");
881: }
882:
1.70 markus 883: /* Initiate port forwardings. */
884: ssh_init_forwarding();
1.34 markus 885:
886: /* If requested, let ssh continue in the background. */
1.48 markus 887: if (fork_after_authentication_flag)
1.34 markus 888: if (daemon(1, 1) < 0)
889: fatal("daemon() failed: %.200s", strerror(errno));
1.31 markus 890:
1.33 markus 891: /*
892: * If a command was specified on the command line, execute the
893: * command now. Otherwise request the server to start a shell.
894: */
1.31 markus 895: if (buffer_len(&command) > 0) {
896: int len = buffer_len(&command);
897: if (len > 900)
898: len = 900;
899: debug("Sending command: %.*s", len, buffer_ptr(&command));
900: packet_start(SSH_CMSG_EXEC_CMD);
901: packet_put_string(buffer_ptr(&command), buffer_len(&command));
902: packet_send();
903: packet_write_wait();
904: } else {
905: debug("Requesting shell.");
906: packet_start(SSH_CMSG_EXEC_SHELL);
907: packet_send();
908: packet_write_wait();
909: }
910:
911: /* Enter the interactive session. */
1.60 markus 912: return client_loop(have_tty, tty_flag ? options.escape_char : -1, 0);
1.45 markus 913: }
914:
915: void
1.89 markus 916: client_subsystem_reply(int type, int plen, void *ctxt)
917: {
918: int id, len;
919:
920: id = packet_get_int();
921: len = buffer_len(&command);
922: len = MAX(len, 900);
923: packet_done();
924: if (type == SSH2_MSG_CHANNEL_FAILURE)
925: fatal("Request for subsystem '%.*s' failed on channel %d",
926: len, buffer_ptr(&command), id);
927: }
928:
929: void
1.70 markus 930: ssh_session2_callback(int id, void *arg)
1.45 markus 931: {
932: int len;
1.80 markus 933: int interactive = 0;
934:
1.87 deraadt 935: debug("client_init id %d arg %ld", id, (long)arg);
1.31 markus 936:
1.45 markus 937: if (no_shell_flag)
938: goto done;
939:
940: if (tty_flag) {
941: struct winsize ws;
942: char *cp;
943: cp = getenv("TERM");
944: if (!cp)
945: cp = "";
946: /* Store window size in the packet. */
947: if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
948: memset(&ws, 0, sizeof(ws));
949:
950: channel_request_start(id, "pty-req", 0);
951: packet_put_cstring(cp);
952: packet_put_int(ws.ws_col);
953: packet_put_int(ws.ws_row);
954: packet_put_int(ws.ws_xpixel);
955: packet_put_int(ws.ws_ypixel);
956: packet_put_cstring(""); /* XXX: encode terminal modes */
957: packet_send();
1.80 markus 958: interactive = 1;
1.45 markus 959: /* XXX wait for reply */
960: }
1.50 markus 961: if (options.forward_x11 &&
962: getenv("DISPLAY") != NULL) {
963: char proto[512], data[512];
964: /* Get reasonable local authentication information. */
965: x11_get_proto(proto, sizeof proto, data, sizeof data);
966: /* Request forwarding with authentication spoofing. */
967: debug("Requesting X11 forwarding with authentication spoofing.");
968: x11_request_forwarding_with_spoofing(id, proto, data);
1.80 markus 969: interactive = 1;
1.50 markus 970: /* XXX wait for reply */
971: }
972:
1.70 markus 973: check_agent_present();
974: if (options.forward_agent) {
975: debug("Requesting authentication agent forwarding.");
976: channel_request_start(id, "auth-agent-req@openssh.com", 0);
977: packet_send();
978: }
979:
1.45 markus 980: len = buffer_len(&command);
981: if (len > 0) {
982: if (len > 900)
983: len = 900;
1.85 djm 984: if (subsystem_flag) {
985: debug("Sending subsystem: %.*s", len, buffer_ptr(&command));
1.89 markus 986: channel_request_start(id, "subsystem", /*want reply*/ 1);
987: /* register callback for reply */
988: /* XXX we asume that client_loop has already been called */
989: dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &client_subsystem_reply);
990: dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &client_subsystem_reply);
1.85 djm 991: } else {
992: debug("Sending command: %.*s", len, buffer_ptr(&command));
993: channel_request_start(id, "exec", 0);
994: }
1.45 markus 995: packet_put_string(buffer_ptr(&command), len);
996: packet_send();
997: } else {
998: channel_request(id, "shell", 0);
999: }
1000: /* channel_callback(id, SSH2_MSG_OPEN_CONFIGMATION, client_init, 0); */
1.90 markus 1001:
1.45 markus 1002: done:
1003: /* register different callback, etc. XXX */
1.80 markus 1004: packet_set_interactive(interactive);
1.45 markus 1005: }
1006:
1007: int
1008: ssh_session2(void)
1009: {
1010: int window, packetmax, id;
1.60 markus 1011: int in, out, err;
1012:
1.62 markus 1013: if (stdin_null_flag) {
1.93 itojun 1014: in = open(_PATH_DEVNULL, O_RDONLY);
1.62 markus 1015: } else {
1016: in = dup(STDIN_FILENO);
1017: }
1.60 markus 1018: out = dup(STDOUT_FILENO);
1019: err = dup(STDERR_FILENO);
1.45 markus 1020:
1021: if (in < 0 || out < 0 || err < 0)
1.62 markus 1022: fatal("dup() in/out/err failed");
1.45 markus 1023:
1.69 markus 1024: /* enable nonblocking unless tty */
1025: if (!isatty(in))
1026: set_nonblock(in);
1027: if (!isatty(out))
1028: set_nonblock(out);
1029: if (!isatty(err))
1030: set_nonblock(err);
1031:
1.70 markus 1032: /* XXX should be pre-session */
1033: ssh_init_forwarding();
1.88 stevesk 1034:
1.62 markus 1035: /* If requested, let ssh continue in the background. */
1036: if (fork_after_authentication_flag)
1037: if (daemon(1, 1) < 0)
1038: fatal("daemon() failed: %.200s", strerror(errno));
1039:
1.65 markus 1040: window = CHAN_SES_WINDOW_DEFAULT;
1041: packetmax = CHAN_SES_PACKET_DEFAULT;
1042: if (!tty_flag) {
1.45 markus 1043: window *= 2;
1.65 markus 1044: packetmax *=2;
1.45 markus 1045: }
1046: id = channel_new(
1047: "session", SSH_CHANNEL_OPENING, in, out, err,
1.65 markus 1048: window, packetmax, CHAN_EXTENDED_WRITE,
1.69 markus 1049: xstrdup("client-session"), /*nonblock*/0);
1.45 markus 1050:
1051: channel_open(id);
1.70 markus 1052: channel_register_callback(id, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION,
1053: ssh_session2_callback, (void *)0);
1.31 markus 1054:
1.60 markus 1055: return client_loop(tty_flag, tty_flag ? options.escape_char : -1, id);
1.72 markus 1056: }
1057:
1058: int
1059: guess_identity_file_type(const char *filename)
1060: {
1061: struct stat st;
1062: Key *public;
1063: int type = KEY_RSA1; /* default */
1064:
1065: if (stat(filename, &st) < 0) {
1.73 markus 1066: /* ignore this key */
1.72 markus 1067: return KEY_UNSPEC;
1068: }
1069: public = key_new(type);
1070: if (!load_public_key(filename, public, NULL)) {
1071: /* ok, so we will assume this is 'some' key */
1072: type = KEY_UNSPEC;
1073: }
1074: key_free(public);
1075: return type;
1.1 deraadt 1076: }