Annotation of src/usr.bin/ssh/ssh.c, Revision 1.99
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"
1.99 ! deraadt 42: RCSID("$OpenBSD: ssh.c,v 1.98 2001/02/22 21:59:44 markus 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");
1.99 ! deraadt 156: fprintf(stderr, " -i file Identity for public key authentication "
! 157: "(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: "
1.99 ! deraadt 169: "``3des'', ``blowfish''\n");
1.31 markus 170: fprintf(stderr, " -p port Connect to this port. Server must be on the same port.\n");
171: fprintf(stderr, " -L listen-port:host:port Forward local port to remote address\n");
172: fprintf(stderr, " -R listen-port:host:port Forward remote port to local address\n");
1.76 markus 173: fprintf(stderr, " These cause %s to listen for connections on a port, and\n", __progname);
1.31 markus 174: fprintf(stderr, " forward them to the other side by connecting to host:port.\n");
175: fprintf(stderr, " -C Enable compression.\n");
1.45 markus 176: fprintf(stderr, " -N Do not execute a shell or command.\n");
1.31 markus 177: fprintf(stderr, " -g Allow remote hosts to connect to forwarded ports.\n");
1.92 jakob 178: fprintf(stderr, " -1 Force protocol version 1.\n");
179: fprintf(stderr, " -2 Force protocol version 2.\n");
1.37 markus 180: fprintf(stderr, " -4 Use IPv4 only.\n");
181: fprintf(stderr, " -6 Use IPv6 only.\n");
1.31 markus 182: fprintf(stderr, " -o 'option' Process the option as if it was read from a configuration file.\n");
1.85 djm 183: fprintf(stderr, " -s Invoke command (mandatory) as SSH2 subsystem.\n");
1.31 markus 184: exit(1);
1.1 deraadt 185: }
186:
1.32 deraadt 187: /*
188: * Connects to the given host using rsh (or prints an error message and exits
189: * if rsh is not available). This function never returns.
190: */
1.2 provos 191: void
1.31 markus 192: rsh_connect(char *host, char *user, Buffer * command)
1.1 deraadt 193: {
1.31 markus 194: char *args[10];
195: int i;
196:
197: log("Using rsh. WARNING: Connection will not be encrypted.");
198: /* Build argument list for rsh. */
199: i = 0;
200: args[i++] = _PATH_RSH;
201: /* host may have to come after user on some systems */
202: args[i++] = host;
203: if (user) {
204: args[i++] = "-l";
205: args[i++] = user;
206: }
207: if (buffer_len(command) > 0) {
208: buffer_append(command, "\0", 1);
209: args[i++] = buffer_ptr(command);
210: }
211: args[i++] = NULL;
212: if (debug_flag) {
213: for (i = 0; args[i]; i++) {
214: if (i != 0)
215: fprintf(stderr, " ");
216: fprintf(stderr, "%s", args[i]);
217: }
218: fprintf(stderr, "\n");
219: }
220: execv(_PATH_RSH, args);
221: perror(_PATH_RSH);
222: exit(1);
1.1 deraadt 223: }
224:
1.72 markus 225: int ssh_session(void);
226: int ssh_session2(void);
227: int guess_identity_file_type(const char *filename);
1.45 markus 228:
1.32 deraadt 229: /*
230: * Main program for the ssh client.
231: */
1.2 provos 232: int
233: main(int ac, char **av)
1.1 deraadt 234: {
1.45 markus 235: int i, opt, optind, exit_status, ok;
1.35 markus 236: u_short fwd_port, fwd_host_port;
1.31 markus 237: char *optarg, *cp, buf[256];
238: struct stat st;
1.98 markus 239: struct passwd *pw;
1.45 markus 240: int dummy;
1.31 markus 241: uid_t original_effective_uid;
242:
1.33 markus 243: /*
244: * Save the original real uid. It will be needed later (uid-swapping
245: * may clobber the real uid).
246: */
1.31 markus 247: original_real_uid = getuid();
248: original_effective_uid = geteuid();
249:
250: /* If we are installed setuid root be careful to not drop core. */
251: if (original_real_uid != original_effective_uid) {
252: struct rlimit rlim;
253: rlim.rlim_cur = rlim.rlim_max = 0;
254: if (setrlimit(RLIMIT_CORE, &rlim) < 0)
255: fatal("setrlimit failed: %.100s", strerror(errno));
1.1 deraadt 256: }
1.33 markus 257: /*
258: * Use uid-swapping to give up root privileges for the duration of
259: * option processing. We will re-instantiate the rights when we are
260: * ready to create the privileged port, and will permanently drop
261: * them when the port has been created (actually, when the connection
262: * has been made, as we may need to create the port several times).
263: */
1.31 markus 264: temporarily_use_uid(original_real_uid);
265:
1.33 markus 266: /*
267: * Set our umask to something reasonable, as some files are created
268: * with the default umask. This will make them world-readable but
269: * writable only by the owner, which is ok for all files for which we
270: * don't set the modes explicitly.
271: */
1.31 markus 272: umask(022);
273:
274: /* Initialize option structure to indicate that no values have been set. */
275: initialize_options(&options);
276:
277: /* Parse command-line arguments. */
278: host = NULL;
279:
280: for (optind = 1; optind < ac; optind++) {
281: if (av[optind][0] != '-') {
282: if (host)
283: break;
284: if ((cp = strchr(av[optind], '@'))) {
1.48 markus 285: if(cp == av[optind])
286: usage();
1.31 markus 287: options.user = av[optind];
288: *cp = '\0';
289: host = ++cp;
290: } else
291: host = av[optind];
292: continue;
293: }
294: opt = av[optind][1];
295: if (!opt)
296: usage();
1.95 markus 297: if (strchr("eilcmpLRo", opt)) { /* options with arguments */
1.31 markus 298: optarg = av[optind] + 2;
299: if (strcmp(optarg, "") == 0) {
300: if (optind >= ac - 1)
301: usage();
302: optarg = av[++optind];
303: }
304: } else {
305: if (av[optind][2])
306: usage();
307: optarg = NULL;
308: }
309: switch (opt) {
1.91 jakob 310: case '1':
311: options.protocol = SSH_PROTO_1;
312: break;
1.47 markus 313: case '2':
314: options.protocol = SSH_PROTO_2;
315: break;
1.37 markus 316: case '4':
317: IPv4or6 = AF_INET;
318: break;
319: case '6':
320: IPv4or6 = AF_INET6;
321: break;
1.31 markus 322: case 'n':
323: stdin_null_flag = 1;
324: break;
325: case 'f':
326: fork_after_authentication_flag = 1;
327: stdin_null_flag = 1;
328: break;
329: case 'x':
330: options.forward_x11 = 0;
331: break;
332: case 'X':
333: options.forward_x11 = 1;
334: break;
335: case 'g':
336: options.gateway_ports = 1;
337: break;
338: case 'P':
339: options.use_privileged_port = 0;
340: break;
341: case 'a':
342: options.forward_agent = 0;
1.53 markus 343: break;
344: case 'A':
345: options.forward_agent = 1;
1.31 markus 346: break;
1.9 dugsong 347: #ifdef AFS
1.31 markus 348: case 'k':
349: options.kerberos_tgt_passing = 0;
350: options.afs_token_passing = 0;
351: break;
1.1 deraadt 352: #endif
1.31 markus 353: case 'i':
354: if (stat(optarg, &st) < 0) {
355: fprintf(stderr, "Warning: Identity file %s does not exist.\n",
1.72 markus 356: optarg);
1.31 markus 357: break;
358: }
359: if (options.num_identity_files >= SSH_MAX_IDENTITY_FILES)
360: fatal("Too many identity files specified (max %d)",
1.72 markus 361: SSH_MAX_IDENTITY_FILES);
362: options.identity_files[options.num_identity_files++] = xstrdup(optarg);
1.31 markus 363: break;
364: case 't':
1.79 markus 365: if (tty_flag)
366: force_tty_flag = 1;
1.31 markus 367: tty_flag = 1;
368: break;
369: case 'v':
1.66 markus 370: if (0 == debug_flag) {
371: debug_flag = 1;
372: options.log_level = SYSLOG_LEVEL_DEBUG1;
373: } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) {
374: options.log_level++;
375: break;
376: } else {
377: fatal("Too high debugging level.\n");
378: }
379: /* fallthrough */
1.31 markus 380: case 'V':
1.96 deraadt 381: fprintf(stderr,
382: "%s, SSH protocols %d.%d/%d.%d, OpenSSL 0x%8.8lx\n",
1.46 markus 383: SSH_VERSION,
384: PROTOCOL_MAJOR_1, PROTOCOL_MINOR_1,
1.96 deraadt 385: PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2,
386: SSLeay());
1.31 markus 387: if (opt == 'V')
388: exit(0);
389: break;
390: case 'q':
391: options.log_level = SYSLOG_LEVEL_QUIET;
392: break;
393: case 'e':
394: if (optarg[0] == '^' && optarg[2] == 0 &&
1.78 markus 395: (u_char) optarg[1] >= 64 && (u_char) optarg[1] < 128)
396: options.escape_char = (u_char) optarg[1] & 31;
1.31 markus 397: else if (strlen(optarg) == 1)
1.78 markus 398: options.escape_char = (u_char) optarg[0];
1.31 markus 399: else if (strcmp(optarg, "none") == 0)
400: options.escape_char = -2;
401: else {
402: fprintf(stderr, "Bad escape character '%s'.\n", optarg);
403: exit(1);
404: }
405: break;
406: case 'c':
1.49 markus 407: if (ciphers_valid(optarg)) {
408: /* SSH2 only */
409: options.ciphers = xstrdup(optarg);
1.51 markus 410: options.cipher = SSH_CIPHER_ILLEGAL;
1.49 markus 411: } else {
412: /* SSH1 only */
1.74 markus 413: options.cipher = cipher_number(optarg);
414: if (options.cipher == -1) {
1.49 markus 415: fprintf(stderr, "Unknown cipher type '%s'\n", optarg);
416: exit(1);
417: }
1.74 markus 418: if (options.cipher == SSH_CIPHER_3DES) {
419: options.ciphers = "3des-cbc";
420: } else if (options.cipher == SSH_CIPHER_BLOWFISH) {
421: options.ciphers = "blowfish-cbc";
422: } else {
423: options.ciphers = (char *)-1;
424: }
1.95 markus 425: }
426: break;
427: case 'm':
428: if (mac_valid(optarg))
429: options.macs = xstrdup(optarg);
430: else {
431: fprintf(stderr, "Unknown mac type '%s'\n", optarg);
432: exit(1);
1.31 markus 433: }
434: break;
435: case 'p':
436: options.port = atoi(optarg);
437: break;
438: case 'l':
439: options.user = optarg;
440: break;
441: case 'R':
1.37 markus 442: if (sscanf(optarg, "%hu/%255[^/]/%hu", &fwd_port, buf,
443: &fwd_host_port) != 3 &&
444: sscanf(optarg, "%hu:%255[^:]:%hu", &fwd_port, buf,
445: &fwd_host_port) != 3) {
1.31 markus 446: fprintf(stderr, "Bad forwarding specification '%s'.\n", optarg);
447: usage();
448: /* NOTREACHED */
449: }
450: add_remote_forward(&options, fwd_port, buf, fwd_host_port);
451: break;
452: case 'L':
1.37 markus 453: if (sscanf(optarg, "%hu/%255[^/]/%hu", &fwd_port, buf,
454: &fwd_host_port) != 3 &&
455: sscanf(optarg, "%hu:%255[^:]:%hu", &fwd_port, buf,
456: &fwd_host_port) != 3) {
1.31 markus 457: fprintf(stderr, "Bad forwarding specification '%s'.\n", optarg);
458: usage();
459: /* NOTREACHED */
460: }
461: add_local_forward(&options, fwd_port, buf, fwd_host_port);
462: break;
463: case 'C':
464: options.compression = 1;
465: break;
1.45 markus 466: case 'N':
467: no_shell_flag = 1;
468: no_tty_flag = 1;
469: break;
470: case 'T':
471: no_tty_flag = 1;
472: break;
1.31 markus 473: case 'o':
474: dummy = 1;
475: if (process_config_line(&options, host ? host : "", optarg,
476: "command-line", 0, &dummy) != 0)
477: exit(1);
478: break;
1.85 djm 479: case 's':
480: subsystem_flag = 1;
481: break;
1.31 markus 482: default:
483: usage();
1.1 deraadt 484: }
1.31 markus 485: }
486:
487: /* Check that we got a host name. */
488: if (!host)
489: usage();
490:
1.54 markus 491: SSLeay_add_all_algorithms();
1.72 markus 492: ERR_load_crypto_strings();
1.31 markus 493:
494: /* Initialize the command to execute on remote host. */
495: buffer_init(&command);
1.1 deraadt 496:
1.33 markus 497: /*
498: * Save the command to execute on the remote host in a buffer. There
499: * is no limit on the length of the command, except by the maximum
500: * packet size. Also sets the tty flag if there is no command.
501: */
1.31 markus 502: if (optind == ac) {
503: /* No command specified - execute shell on a tty. */
504: tty_flag = 1;
1.85 djm 505: if (subsystem_flag) {
506: fprintf(stderr, "You must specify a subsystem to invoke.");
507: usage();
508: }
1.31 markus 509: } else {
510: /* A command has been specified. Store it into the
511: buffer. */
512: for (i = optind; i < ac; i++) {
513: if (i > optind)
514: buffer_append(&command, " ", 1);
515: buffer_append(&command, av[i], strlen(av[i]));
516: }
517: }
518:
519: /* Cannot fork to background if no command. */
1.63 markus 520: if (fork_after_authentication_flag && buffer_len(&command) == 0 && !no_shell_flag)
1.31 markus 521: fatal("Cannot fork into background without a command to execute.");
522:
523: /* Allocate a tty by default if no command specified. */
524: if (buffer_len(&command) == 0)
525: tty_flag = 1;
526:
1.75 markus 527: /* Force no tty*/
528: if (no_tty_flag)
529: tty_flag = 0;
1.31 markus 530: /* Do not allocate a tty if stdin is not a tty. */
1.79 markus 531: if (!isatty(fileno(stdin)) && !force_tty_flag) {
1.31 markus 532: if (tty_flag)
1.82 markus 533: log("Pseudo-terminal will not be allocated because stdin is not a terminal.\n");
1.31 markus 534: tty_flag = 0;
535: }
1.45 markus 536:
1.31 markus 537: /* Get user data. */
538: pw = getpwuid(original_real_uid);
539: if (!pw) {
1.82 markus 540: log("You don't exist, go away!\n");
1.31 markus 541: exit(1);
542: }
543: /* Take a copy of the returned structure. */
1.98 markus 544: pw = pwcopy(pw);
1.31 markus 545:
546: /* Initialize "log" output. Since we are the client all output
547: actually goes to the terminal. */
548: log_init(av[0], options.log_level, SYSLOG_FACILITY_USER, 0);
549:
550: /* Read per-user configuration file. */
1.83 markus 551: snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir, _PATH_SSH_USER_CONFFILE);
1.31 markus 552: read_config_file(buf, host, &options);
553:
554: /* Read systemwide configuration file. */
1.83 markus 555: read_config_file(_PATH_HOST_CONFIG_FILE, host, &options);
1.31 markus 556:
557: /* Fill configuration defaults. */
558: fill_default_options(&options);
559:
560: /* reinit */
561: log_init(av[0], options.log_level, SYSLOG_FACILITY_USER, 0);
562:
563: if (options.user == NULL)
564: options.user = xstrdup(pw->pw_name);
565:
566: if (options.hostname != NULL)
567: host = options.hostname;
568:
569: /* Disable rhosts authentication if not running as root. */
570: if (original_effective_uid != 0 || !options.use_privileged_port) {
1.77 markus 571: debug("Rhosts Authentication disabled, "
1.71 markus 572: "originating port will not be trusted.");
1.31 markus 573: options.rhosts_authentication = 0;
574: }
1.33 markus 575: /*
576: * If using rsh has been selected, exec it now (without trying
577: * anything else). Note that we must release privileges first.
578: */
1.31 markus 579: if (options.use_rsh) {
1.33 markus 580: /*
581: * Restore our superuser privileges. This must be done
582: * before permanently setting the uid.
583: */
1.31 markus 584: restore_uid();
585:
586: /* Switch to the original uid permanently. */
587: permanently_set_uid(original_real_uid);
588:
589: /* Execute rsh. */
590: rsh_connect(host, options.user, &command);
591: fatal("rsh_connect returned");
592: }
593: /* Restore our superuser privileges. */
594: restore_uid();
595:
1.77 markus 596: /* Open a connection to the remote host. */
1.31 markus 597:
598: ok = ssh_connect(host, &hostaddr, options.port,
1.77 markus 599: options.connection_attempts,
600: original_effective_uid != 0 || !options.use_privileged_port,
601: original_real_uid,
602: options.proxy_command);
1.31 markus 603:
1.33 markus 604: /*
605: * If we successfully made the connection, load the host private key
606: * in case we will need it later for combined rsa-rhosts
607: * authentication. This must be done before releasing extra
608: * privileges, because the file is only readable by root.
609: */
1.49 markus 610: if (ok && (options.protocol & SSH_PROTO_1)) {
611: Key k;
1.31 markus 612: host_private_key = RSA_new();
1.72 markus 613: k.type = KEY_RSA1;
1.49 markus 614: k.rsa = host_private_key;
1.83 markus 615: if (load_private_key(_PATH_HOST_KEY_FILE, "", &k, NULL))
1.31 markus 616: host_private_key_loaded = 1;
617: }
1.33 markus 618: /*
619: * Get rid of any extra privileges that we may have. We will no
620: * longer need them. Also, extra privileges could make it very hard
621: * to read identity files and other non-world-readable files from the
622: * user's home directory if it happens to be on a NFS volume where
623: * root is mapped to nobody.
624: */
625:
626: /*
627: * Note that some legacy systems need to postpone the following call
628: * to permanently_set_uid() until the private hostkey is destroyed
629: * with RSA_free(). Otherwise the calling user could ptrace() the
630: * process, read the private hostkey and impersonate the host.
631: * OpenBSD does not allow ptracing of setuid processes.
632: */
1.31 markus 633: permanently_set_uid(original_real_uid);
634:
1.33 markus 635: /*
636: * Now that we are back to our own permissions, create ~/.ssh
637: * directory if it doesn\'t already exist.
638: */
1.83 markus 639: snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir, _PATH_SSH_USER_DIR);
1.31 markus 640: if (stat(buf, &st) < 0)
1.57 djm 641: if (mkdir(buf, 0700) < 0)
1.31 markus 642: error("Could not create directory '%.200s'.", buf);
643:
644: /* Check if the connection failed, and try "rsh" if appropriate. */
645: if (!ok) {
646: if (options.port != 0)
1.35 markus 647: log("Secure connection to %.100s on port %hu refused%.100s.",
1.31 markus 648: host, options.port,
649: options.fallback_to_rsh ? "; reverting to insecure method" : "");
650: else
651: log("Secure connection to %.100s refused%.100s.", host,
652: options.fallback_to_rsh ? "; reverting to insecure method" : "");
653:
654: if (options.fallback_to_rsh) {
655: rsh_connect(host, options.user, &command);
656: fatal("rsh_connect returned");
657: }
658: exit(1);
659: }
1.72 markus 660: /* Expand ~ in options.identity_files, known host file names. */
1.49 markus 661: /* XXX mem-leaks */
1.72 markus 662: for (i = 0; i < options.num_identity_files; i++) {
1.31 markus 663: options.identity_files[i] =
1.72 markus 664: tilde_expand_filename(options.identity_files[i], original_real_uid);
665: options.identity_files_type[i] = guess_identity_file_type(options.identity_files[i]);
666: debug("identity file %s type %d", options.identity_files[i],
667: options.identity_files_type[i]);
668: }
669: options.system_hostfile =
670: tilde_expand_filename(options.system_hostfile, original_real_uid);
671: options.user_hostfile =
672: tilde_expand_filename(options.user_hostfile, original_real_uid);
673: options.system_hostfile2 =
674: tilde_expand_filename(options.system_hostfile2, original_real_uid);
675: options.user_hostfile2 =
676: tilde_expand_filename(options.user_hostfile2, original_real_uid);
1.31 markus 677:
678: /* Log into the remote system. This never returns if the login fails. */
679: ssh_login(host_private_key_loaded, host_private_key,
1.37 markus 680: host, (struct sockaddr *)&hostaddr, original_real_uid);
1.31 markus 681:
682: /* We no longer need the host private key. Clear it now. */
683: if (host_private_key_loaded)
684: RSA_free(host_private_key); /* Destroys contents safely */
685:
1.45 markus 686: exit_status = compat20 ? ssh_session2() : ssh_session();
687: packet_close();
688: return exit_status;
689: }
690:
1.50 markus 691: void
692: x11_get_proto(char *proto, int proto_len, char *data, int data_len)
693: {
694: char line[512];
695: FILE *f;
696: int got_data = 0, i;
697:
1.55 markus 698: if (options.xauth_location) {
699: /* Try to get Xauthority information for the display. */
1.93 itojun 700: snprintf(line, sizeof line, "%.100s list %.200s 2>" _PATH_DEVNULL,
1.55 markus 701: options.xauth_location, getenv("DISPLAY"));
702: f = popen(line, "r");
703: if (f && fgets(line, sizeof(line), f) &&
704: sscanf(line, "%*s %s %s", proto, data) == 2)
705: got_data = 1;
706: if (f)
707: pclose(f);
708: }
1.50 markus 709: /*
710: * If we didn't get authentication data, just make up some
711: * data. The forwarding code will check the validity of the
712: * response anyway, and substitute this data. The X11
713: * server, however, will ignore this fake data and use
714: * whatever authentication mechanisms it was using otherwise
715: * for the local connection.
716: */
717: if (!got_data) {
718: u_int32_t rand = 0;
719:
720: strlcpy(proto, "MIT-MAGIC-COOKIE-1", proto_len);
721: for (i = 0; i < 16; i++) {
722: if (i % 4 == 0)
723: rand = arc4random();
724: snprintf(data + 2 * i, data_len - 2 * i, "%02x", rand & 0xff);
725: rand >>= 8;
726: }
727: }
728: }
729:
1.70 markus 730: void
731: ssh_init_forwarding(void)
732: {
1.86 markus 733: int success = 0;
1.70 markus 734: int i;
1.86 markus 735:
1.70 markus 736: /* Initiate local TCP/IP port forwardings. */
737: for (i = 0; i < options.num_local_forwards; i++) {
738: debug("Connections to local port %d forwarded to remote address %.200s:%d",
739: options.local_forwards[i].port,
740: options.local_forwards[i].host,
741: options.local_forwards[i].host_port);
1.86 markus 742: success += channel_request_local_forwarding(
1.70 markus 743: options.local_forwards[i].port,
744: options.local_forwards[i].host,
745: options.local_forwards[i].host_port,
746: options.gateway_ports);
747: }
1.86 markus 748: if (i > 0 && success == 0)
749: error("Could not request local forwarding.");
1.70 markus 750:
751: /* Initiate remote TCP/IP port forwardings. */
752: for (i = 0; i < options.num_remote_forwards; i++) {
753: debug("Connections to remote port %d forwarded to local address %.200s:%d",
754: options.remote_forwards[i].port,
755: options.remote_forwards[i].host,
756: options.remote_forwards[i].host_port);
757: channel_request_remote_forwarding(
758: options.remote_forwards[i].port,
759: options.remote_forwards[i].host,
760: options.remote_forwards[i].host_port);
761: }
762: }
763:
764: void
765: check_agent_present(void)
766: {
767: if (options.forward_agent) {
768: /* Clear agent forwarding if we don\'t have an agent. */
769: int authfd = ssh_get_authentication_socket();
770: if (authfd < 0)
771: options.forward_agent = 0;
772: else
773: ssh_close_authentication_socket(authfd);
774: }
775: }
776:
1.45 markus 777: int
778: ssh_session(void)
779: {
780: int type;
781: int plen;
782: int interactive = 0;
783: int have_tty = 0;
784: struct winsize ws;
785: char *cp;
786:
1.31 markus 787: /* Enable compression if requested. */
788: if (options.compression) {
789: debug("Requesting compression at level %d.", options.compression_level);
790:
791: if (options.compression_level < 1 || options.compression_level > 9)
792: fatal("Compression level must be from 1 (fast) to 9 (slow, best).");
793:
794: /* Send the request. */
795: packet_start(SSH_CMSG_REQUEST_COMPRESSION);
796: packet_put_int(options.compression_level);
797: packet_send();
798: packet_write_wait();
799: type = packet_read(&plen);
800: if (type == SSH_SMSG_SUCCESS)
801: packet_start_compression(options.compression_level);
802: else if (type == SSH_SMSG_FAILURE)
803: log("Warning: Remote host refused compression.");
804: else
805: packet_disconnect("Protocol error waiting for compression response.");
806: }
807: /* Allocate a pseudo tty if appropriate. */
808: if (tty_flag) {
809: debug("Requesting pty.");
810:
811: /* Start the packet. */
812: packet_start(SSH_CMSG_REQUEST_PTY);
813:
814: /* Store TERM in the packet. There is no limit on the
815: length of the string. */
816: cp = getenv("TERM");
817: if (!cp)
818: cp = "";
819: packet_put_string(cp, strlen(cp));
820:
821: /* Store window size in the packet. */
822: if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
823: memset(&ws, 0, sizeof(ws));
824: packet_put_int(ws.ws_row);
825: packet_put_int(ws.ws_col);
826: packet_put_int(ws.ws_xpixel);
827: packet_put_int(ws.ws_ypixel);
828:
829: /* Store tty modes in the packet. */
830: tty_make_modes(fileno(stdin));
831:
832: /* Send the packet, and wait for it to leave. */
833: packet_send();
834: packet_write_wait();
835:
836: /* Read response from the server. */
837: type = packet_read(&plen);
1.43 markus 838: if (type == SSH_SMSG_SUCCESS) {
1.31 markus 839: interactive = 1;
1.45 markus 840: have_tty = 1;
1.43 markus 841: } else if (type == SSH_SMSG_FAILURE)
1.31 markus 842: log("Warning: Remote host failed or refused to allocate a pseudo tty.");
843: else
844: packet_disconnect("Protocol error waiting for pty request response.");
845: }
846: /* Request X11 forwarding if enabled and DISPLAY is set. */
847: if (options.forward_x11 && getenv("DISPLAY") != NULL) {
1.50 markus 848: char proto[512], data[512];
849: /* Get reasonable local authentication information. */
850: x11_get_proto(proto, sizeof proto, data, sizeof data);
851: /* Request forwarding with authentication spoofing. */
1.31 markus 852: debug("Requesting X11 forwarding with authentication spoofing.");
1.50 markus 853: x11_request_forwarding_with_spoofing(0, proto, data);
1.31 markus 854:
855: /* Read response from the server. */
856: type = packet_read(&plen);
857: if (type == SSH_SMSG_SUCCESS) {
858: interactive = 1;
1.50 markus 859: } else if (type == SSH_SMSG_FAILURE) {
1.31 markus 860: log("Warning: Remote host denied X11 forwarding.");
1.50 markus 861: } else {
1.31 markus 862: packet_disconnect("Protocol error waiting for X11 forwarding");
1.50 markus 863: }
1.31 markus 864: }
865: /* Tell the packet module whether this is an interactive session. */
1.80 markus 866: packet_set_interactive(interactive);
1.31 markus 867:
868: /* Request authentication agent forwarding if appropriate. */
1.70 markus 869: check_agent_present();
870:
1.31 markus 871: if (options.forward_agent) {
872: debug("Requesting authentication agent forwarding.");
873: auth_request_forwarding();
874:
875: /* Read response from the server. */
876: type = packet_read(&plen);
877: packet_integrity_check(plen, 0, type);
878: if (type != SSH_SMSG_SUCCESS)
879: log("Warning: Remote host denied authentication agent forwarding.");
880: }
881:
1.70 markus 882: /* Initiate port forwardings. */
883: ssh_init_forwarding();
1.34 markus 884:
885: /* If requested, let ssh continue in the background. */
1.48 markus 886: if (fork_after_authentication_flag)
1.34 markus 887: if (daemon(1, 1) < 0)
888: fatal("daemon() failed: %.200s", strerror(errno));
1.31 markus 889:
1.33 markus 890: /*
891: * If a command was specified on the command line, execute the
892: * command now. Otherwise request the server to start a shell.
893: */
1.31 markus 894: if (buffer_len(&command) > 0) {
895: int len = buffer_len(&command);
896: if (len > 900)
897: len = 900;
898: debug("Sending command: %.*s", len, buffer_ptr(&command));
899: packet_start(SSH_CMSG_EXEC_CMD);
900: packet_put_string(buffer_ptr(&command), buffer_len(&command));
901: packet_send();
902: packet_write_wait();
903: } else {
904: debug("Requesting shell.");
905: packet_start(SSH_CMSG_EXEC_SHELL);
906: packet_send();
907: packet_write_wait();
908: }
909:
910: /* Enter the interactive session. */
1.60 markus 911: return client_loop(have_tty, tty_flag ? options.escape_char : -1, 0);
1.45 markus 912: }
913:
914: void
1.89 markus 915: client_subsystem_reply(int type, int plen, void *ctxt)
916: {
917: int id, len;
918:
919: id = packet_get_int();
920: len = buffer_len(&command);
921: len = MAX(len, 900);
922: packet_done();
923: if (type == SSH2_MSG_CHANNEL_FAILURE)
924: fatal("Request for subsystem '%.*s' failed on channel %d",
925: len, buffer_ptr(&command), id);
926: }
927:
928: void
1.70 markus 929: ssh_session2_callback(int id, void *arg)
1.45 markus 930: {
931: int len;
1.80 markus 932: int interactive = 0;
933:
1.87 deraadt 934: debug("client_init id %d arg %ld", id, (long)arg);
1.31 markus 935:
1.45 markus 936: if (no_shell_flag)
937: goto done;
938:
939: if (tty_flag) {
940: struct winsize ws;
941: char *cp;
942: cp = getenv("TERM");
943: if (!cp)
944: cp = "";
945: /* Store window size in the packet. */
946: if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
947: memset(&ws, 0, sizeof(ws));
948:
949: channel_request_start(id, "pty-req", 0);
950: packet_put_cstring(cp);
951: packet_put_int(ws.ws_col);
952: packet_put_int(ws.ws_row);
953: packet_put_int(ws.ws_xpixel);
954: packet_put_int(ws.ws_ypixel);
955: packet_put_cstring(""); /* XXX: encode terminal modes */
956: packet_send();
1.80 markus 957: interactive = 1;
1.45 markus 958: /* XXX wait for reply */
959: }
1.50 markus 960: if (options.forward_x11 &&
961: getenv("DISPLAY") != NULL) {
962: char proto[512], data[512];
963: /* Get reasonable local authentication information. */
964: x11_get_proto(proto, sizeof proto, data, sizeof data);
965: /* Request forwarding with authentication spoofing. */
966: debug("Requesting X11 forwarding with authentication spoofing.");
967: x11_request_forwarding_with_spoofing(id, proto, data);
1.80 markus 968: interactive = 1;
1.50 markus 969: /* XXX wait for reply */
970: }
971:
1.70 markus 972: check_agent_present();
973: if (options.forward_agent) {
974: debug("Requesting authentication agent forwarding.");
975: channel_request_start(id, "auth-agent-req@openssh.com", 0);
976: packet_send();
977: }
978:
1.45 markus 979: len = buffer_len(&command);
980: if (len > 0) {
981: if (len > 900)
982: len = 900;
1.85 djm 983: if (subsystem_flag) {
984: debug("Sending subsystem: %.*s", len, buffer_ptr(&command));
1.89 markus 985: channel_request_start(id, "subsystem", /*want reply*/ 1);
986: /* register callback for reply */
987: /* XXX we asume that client_loop has already been called */
988: dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &client_subsystem_reply);
989: dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &client_subsystem_reply);
1.85 djm 990: } else {
991: debug("Sending command: %.*s", len, buffer_ptr(&command));
992: channel_request_start(id, "exec", 0);
993: }
1.45 markus 994: packet_put_string(buffer_ptr(&command), len);
995: packet_send();
996: } else {
997: channel_request(id, "shell", 0);
998: }
999: /* channel_callback(id, SSH2_MSG_OPEN_CONFIGMATION, client_init, 0); */
1.90 markus 1000:
1.45 markus 1001: done:
1002: /* register different callback, etc. XXX */
1.80 markus 1003: packet_set_interactive(interactive);
1.45 markus 1004: }
1005:
1006: int
1007: ssh_session2(void)
1008: {
1009: int window, packetmax, id;
1.60 markus 1010: int in, out, err;
1011:
1.62 markus 1012: if (stdin_null_flag) {
1.93 itojun 1013: in = open(_PATH_DEVNULL, O_RDONLY);
1.62 markus 1014: } else {
1015: in = dup(STDIN_FILENO);
1016: }
1.60 markus 1017: out = dup(STDOUT_FILENO);
1018: err = dup(STDERR_FILENO);
1.45 markus 1019:
1020: if (in < 0 || out < 0 || err < 0)
1.62 markus 1021: fatal("dup() in/out/err failed");
1.45 markus 1022:
1.69 markus 1023: /* enable nonblocking unless tty */
1024: if (!isatty(in))
1025: set_nonblock(in);
1026: if (!isatty(out))
1027: set_nonblock(out);
1028: if (!isatty(err))
1029: set_nonblock(err);
1030:
1.70 markus 1031: /* XXX should be pre-session */
1032: ssh_init_forwarding();
1.88 stevesk 1033:
1.62 markus 1034: /* If requested, let ssh continue in the background. */
1035: if (fork_after_authentication_flag)
1036: if (daemon(1, 1) < 0)
1037: fatal("daemon() failed: %.200s", strerror(errno));
1038:
1.65 markus 1039: window = CHAN_SES_WINDOW_DEFAULT;
1040: packetmax = CHAN_SES_PACKET_DEFAULT;
1041: if (!tty_flag) {
1.45 markus 1042: window *= 2;
1.65 markus 1043: packetmax *=2;
1.45 markus 1044: }
1045: id = channel_new(
1046: "session", SSH_CHANNEL_OPENING, in, out, err,
1.65 markus 1047: window, packetmax, CHAN_EXTENDED_WRITE,
1.69 markus 1048: xstrdup("client-session"), /*nonblock*/0);
1.45 markus 1049:
1050: channel_open(id);
1.70 markus 1051: channel_register_callback(id, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION,
1052: ssh_session2_callback, (void *)0);
1.31 markus 1053:
1.60 markus 1054: return client_loop(tty_flag, tty_flag ? options.escape_char : -1, id);
1.72 markus 1055: }
1056:
1057: int
1058: guess_identity_file_type(const char *filename)
1059: {
1060: struct stat st;
1061: Key *public;
1062: int type = KEY_RSA1; /* default */
1063:
1064: if (stat(filename, &st) < 0) {
1.73 markus 1065: /* ignore this key */
1.72 markus 1066: return KEY_UNSPEC;
1067: }
1068: public = key_new(type);
1069: if (!load_public_key(filename, public, NULL)) {
1070: /* ok, so we will assume this is 'some' key */
1071: type = KEY_UNSPEC;
1072: }
1073: key_free(public);
1074: return type;
1.1 deraadt 1075: }
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