Annotation of src/usr.bin/ssh/ssh.c, Revision 1.110
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"
1.110 ! markus 42: RCSID("$OpenBSD: ssh.c,v 1.109 2001/04/11 10:59:01 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: /* Host private key. */
1.105 markus 126: Key *host_private_key = NULL;
1.1 deraadt 127:
1.10 dugsong 128: /* Original real UID. */
129: uid_t original_real_uid;
1.1 deraadt 130:
1.45 markus 131: /* command to be executed */
132: Buffer command;
133:
1.85 djm 134: /* Should we execute a command or invoke a subsystem? */
135: int subsystem_flag = 0;
136:
1.1 deraadt 137: /* Prints a help message to the user. This function never returns. */
138:
1.2 provos 139: void
1.93 itojun 140: usage(void)
1.1 deraadt 141: {
1.76 markus 142: fprintf(stderr, "Usage: %s [options] host [command]\n", __progname);
1.31 markus 143: fprintf(stderr, "Options:\n");
144: fprintf(stderr, " -l user Log in using this user name.\n");
1.93 itojun 145: fprintf(stderr, " -n Redirect input from " _PATH_DEVNULL ".\n");
1.53 markus 146: fprintf(stderr, " -A Enable authentication agent forwarding.\n");
1.31 markus 147: fprintf(stderr, " -a Disable authentication agent forwarding.\n");
1.9 dugsong 148: #ifdef AFS
1.31 markus 149: fprintf(stderr, " -k Disable Kerberos ticket and AFS token forwarding.\n");
150: #endif /* AFS */
1.88 stevesk 151: fprintf(stderr, " -X Enable X11 connection forwarding.\n");
1.31 markus 152: fprintf(stderr, " -x Disable X11 connection forwarding.\n");
1.99 deraadt 153: fprintf(stderr, " -i file Identity for public key authentication "
154: "(default: ~/.ssh/identity)\n");
1.31 markus 155: fprintf(stderr, " -t Tty; allocate a tty even if command is given.\n");
1.45 markus 156: fprintf(stderr, " -T Do not allocate a tty.\n");
1.31 markus 157: fprintf(stderr, " -v Verbose; display verbose debugging messages.\n");
1.66 markus 158: fprintf(stderr, " Multiple -v increases verbosity.\n");
1.31 markus 159: fprintf(stderr, " -V Display version number only.\n");
160: fprintf(stderr, " -P Don't allocate a privileged port.\n");
161: fprintf(stderr, " -q Quiet; don't display any warning messages.\n");
162: fprintf(stderr, " -f Fork into background after authentication.\n");
163: fprintf(stderr, " -e char Set escape character; ``none'' = disable (default: ~).\n");
164:
165: fprintf(stderr, " -c cipher Select encryption algorithm: "
1.99 deraadt 166: "``3des'', ``blowfish''\n");
1.102 stevesk 167: fprintf(stderr, " -m macs Specify MAC algorithms for protocol version 2.\n");
1.31 markus 168: fprintf(stderr, " -p port Connect to this port. Server must be on the same port.\n");
169: fprintf(stderr, " -L listen-port:host:port Forward local port to remote address\n");
170: fprintf(stderr, " -R listen-port:host:port Forward remote port to local address\n");
1.76 markus 171: fprintf(stderr, " These cause %s to listen for connections on a port, and\n", __progname);
1.31 markus 172: fprintf(stderr, " forward them to the other side by connecting to host:port.\n");
1.108 markus 173: fprintf(stderr, " -D port Dynamically forward local port to multiple remote addresses.\n");
1.110 ! markus 174: fprintf(stderr, " Allows %s to act as an application-layer proxy.\n",
! 175: __progname);
! 176: fprintf(stderr, " Protocols supported: SOCKS4, SOCKS5, HTTPS\n");
1.31 markus 177: fprintf(stderr, " -C Enable compression.\n");
1.45 markus 178: fprintf(stderr, " -N Do not execute a shell or command.\n");
1.31 markus 179: fprintf(stderr, " -g Allow remote hosts to connect to forwarded ports.\n");
1.92 jakob 180: fprintf(stderr, " -1 Force protocol version 1.\n");
181: fprintf(stderr, " -2 Force protocol version 2.\n");
1.37 markus 182: fprintf(stderr, " -4 Use IPv4 only.\n");
183: fprintf(stderr, " -6 Use IPv6 only.\n");
1.31 markus 184: fprintf(stderr, " -o 'option' Process the option as if it was read from a configuration file.\n");
1.85 djm 185: fprintf(stderr, " -s Invoke command (mandatory) as SSH2 subsystem.\n");
1.31 markus 186: exit(1);
1.1 deraadt 187: }
188:
1.32 deraadt 189: /*
190: * Connects to the given host using rsh (or prints an error message and exits
191: * if rsh is not available). This function never returns.
192: */
1.2 provos 193: void
1.31 markus 194: rsh_connect(char *host, char *user, Buffer * command)
1.1 deraadt 195: {
1.31 markus 196: char *args[10];
197: int i;
198:
199: log("Using rsh. WARNING: Connection will not be encrypted.");
200: /* Build argument list for rsh. */
201: i = 0;
202: args[i++] = _PATH_RSH;
203: /* host may have to come after user on some systems */
204: args[i++] = host;
205: if (user) {
206: args[i++] = "-l";
207: args[i++] = user;
208: }
209: if (buffer_len(command) > 0) {
210: buffer_append(command, "\0", 1);
211: args[i++] = buffer_ptr(command);
212: }
213: args[i++] = NULL;
214: if (debug_flag) {
215: for (i = 0; args[i]; i++) {
216: if (i != 0)
217: fprintf(stderr, " ");
218: fprintf(stderr, "%s", args[i]);
219: }
220: fprintf(stderr, "\n");
221: }
222: execv(_PATH_RSH, args);
223: perror(_PATH_RSH);
224: exit(1);
1.1 deraadt 225: }
226:
1.72 markus 227: int ssh_session(void);
228: int ssh_session2(void);
1.104 markus 229: void load_public_identity_files(void);
1.45 markus 230:
1.32 deraadt 231: /*
232: * Main program for the ssh client.
233: */
1.2 provos 234: int
235: main(int ac, char **av)
1.1 deraadt 236: {
1.45 markus 237: int i, opt, optind, exit_status, ok;
1.35 markus 238: u_short fwd_port, fwd_host_port;
1.109 markus 239: char *optarg, *cp, *endofnumber, buf[256];
1.31 markus 240: struct stat st;
1.98 markus 241: struct passwd *pw;
1.45 markus 242: int dummy;
1.31 markus 243: uid_t original_effective_uid;
244:
1.33 markus 245: /*
246: * Save the original real uid. It will be needed later (uid-swapping
247: * may clobber the real uid).
248: */
1.31 markus 249: original_real_uid = getuid();
250: original_effective_uid = geteuid();
251:
252: /* If we are installed setuid root be careful to not drop core. */
253: if (original_real_uid != original_effective_uid) {
254: struct rlimit rlim;
255: rlim.rlim_cur = rlim.rlim_max = 0;
256: if (setrlimit(RLIMIT_CORE, &rlim) < 0)
257: fatal("setrlimit failed: %.100s", strerror(errno));
1.1 deraadt 258: }
1.107 markus 259: /* Get user data. */
260: pw = getpwuid(original_real_uid);
261: if (!pw) {
262: log("You don't exist, go away!");
263: exit(1);
264: }
265: /* Take a copy of the returned structure. */
266: pw = pwcopy(pw);
267:
1.33 markus 268: /*
269: * Use uid-swapping to give up root privileges for the duration of
270: * option processing. We will re-instantiate the rights when we are
271: * ready to create the privileged port, and will permanently drop
272: * them when the port has been created (actually, when the connection
273: * has been made, as we may need to create the port several times).
274: */
1.107 markus 275: temporarily_use_uid(pw);
1.31 markus 276:
1.33 markus 277: /*
278: * Set our umask to something reasonable, as some files are created
279: * with the default umask. This will make them world-readable but
280: * writable only by the owner, which is ok for all files for which we
281: * don't set the modes explicitly.
282: */
1.31 markus 283: umask(022);
284:
285: /* Initialize option structure to indicate that no values have been set. */
286: initialize_options(&options);
287:
288: /* Parse command-line arguments. */
289: host = NULL;
290:
291: for (optind = 1; optind < ac; optind++) {
292: if (av[optind][0] != '-') {
293: if (host)
294: break;
295: if ((cp = strchr(av[optind], '@'))) {
1.48 markus 296: if(cp == av[optind])
297: usage();
1.31 markus 298: options.user = av[optind];
299: *cp = '\0';
300: host = ++cp;
301: } else
302: host = av[optind];
303: continue;
304: }
305: opt = av[optind][1];
306: if (!opt)
307: usage();
1.108 markus 308: if (strchr("eilcmpLRDo", opt)) { /* options with arguments */
1.31 markus 309: optarg = av[optind] + 2;
310: if (strcmp(optarg, "") == 0) {
311: if (optind >= ac - 1)
312: usage();
313: optarg = av[++optind];
314: }
315: } else {
316: if (av[optind][2])
317: usage();
318: optarg = NULL;
319: }
320: switch (opt) {
1.91 jakob 321: case '1':
322: options.protocol = SSH_PROTO_1;
323: break;
1.47 markus 324: case '2':
325: options.protocol = SSH_PROTO_2;
326: break;
1.37 markus 327: case '4':
328: IPv4or6 = AF_INET;
329: break;
330: case '6':
331: IPv4or6 = AF_INET6;
332: break;
1.31 markus 333: case 'n':
334: stdin_null_flag = 1;
335: break;
336: case 'f':
337: fork_after_authentication_flag = 1;
338: stdin_null_flag = 1;
339: break;
340: case 'x':
341: options.forward_x11 = 0;
342: break;
343: case 'X':
344: options.forward_x11 = 1;
345: break;
346: case 'g':
347: options.gateway_ports = 1;
348: break;
349: case 'P':
350: options.use_privileged_port = 0;
351: break;
352: case 'a':
353: options.forward_agent = 0;
1.53 markus 354: break;
355: case 'A':
356: options.forward_agent = 1;
1.31 markus 357: break;
1.9 dugsong 358: #ifdef AFS
1.31 markus 359: case 'k':
360: options.kerberos_tgt_passing = 0;
361: options.afs_token_passing = 0;
362: break;
1.1 deraadt 363: #endif
1.31 markus 364: case 'i':
365: if (stat(optarg, &st) < 0) {
366: fprintf(stderr, "Warning: Identity file %s does not exist.\n",
1.72 markus 367: optarg);
1.31 markus 368: break;
369: }
370: if (options.num_identity_files >= SSH_MAX_IDENTITY_FILES)
371: fatal("Too many identity files specified (max %d)",
1.72 markus 372: SSH_MAX_IDENTITY_FILES);
373: options.identity_files[options.num_identity_files++] = xstrdup(optarg);
1.31 markus 374: break;
375: case 't':
1.79 markus 376: if (tty_flag)
377: force_tty_flag = 1;
1.31 markus 378: tty_flag = 1;
379: break;
380: case 'v':
1.66 markus 381: if (0 == debug_flag) {
382: debug_flag = 1;
383: options.log_level = SYSLOG_LEVEL_DEBUG1;
384: } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) {
385: options.log_level++;
386: break;
387: } else {
1.103 millert 388: fatal("Too high debugging level.");
1.66 markus 389: }
390: /* fallthrough */
1.31 markus 391: case 'V':
1.96 deraadt 392: fprintf(stderr,
393: "%s, SSH protocols %d.%d/%d.%d, OpenSSL 0x%8.8lx\n",
1.46 markus 394: SSH_VERSION,
395: PROTOCOL_MAJOR_1, PROTOCOL_MINOR_1,
1.96 deraadt 396: PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2,
397: SSLeay());
1.31 markus 398: if (opt == 'V')
399: exit(0);
400: break;
401: case 'q':
402: options.log_level = SYSLOG_LEVEL_QUIET;
403: break;
404: case 'e':
405: if (optarg[0] == '^' && optarg[2] == 0 &&
1.78 markus 406: (u_char) optarg[1] >= 64 && (u_char) optarg[1] < 128)
407: options.escape_char = (u_char) optarg[1] & 31;
1.31 markus 408: else if (strlen(optarg) == 1)
1.78 markus 409: options.escape_char = (u_char) optarg[0];
1.31 markus 410: else if (strcmp(optarg, "none") == 0)
411: options.escape_char = -2;
412: else {
413: fprintf(stderr, "Bad escape character '%s'.\n", optarg);
414: exit(1);
415: }
416: break;
417: case 'c':
1.49 markus 418: if (ciphers_valid(optarg)) {
419: /* SSH2 only */
420: options.ciphers = xstrdup(optarg);
1.51 markus 421: options.cipher = SSH_CIPHER_ILLEGAL;
1.49 markus 422: } else {
423: /* SSH1 only */
1.74 markus 424: options.cipher = cipher_number(optarg);
425: if (options.cipher == -1) {
1.49 markus 426: fprintf(stderr, "Unknown cipher type '%s'\n", optarg);
427: exit(1);
428: }
1.74 markus 429: if (options.cipher == SSH_CIPHER_3DES) {
430: options.ciphers = "3des-cbc";
431: } else if (options.cipher == SSH_CIPHER_BLOWFISH) {
432: options.ciphers = "blowfish-cbc";
433: } else {
434: options.ciphers = (char *)-1;
435: }
1.95 markus 436: }
437: break;
438: case 'm':
439: if (mac_valid(optarg))
440: options.macs = xstrdup(optarg);
441: else {
442: fprintf(stderr, "Unknown mac type '%s'\n", optarg);
443: exit(1);
1.31 markus 444: }
445: break;
446: case 'p':
1.109 markus 447: options.port = strtol(optarg, &endofnumber, 0);
448: if (optarg == endofnumber) {
449: fprintf(stderr, "Bad port '%s'\n", optarg);
450: exit(1);
451: }
1.31 markus 452: break;
453: case 'l':
454: options.user = optarg;
455: break;
456: case 'R':
1.37 markus 457: if (sscanf(optarg, "%hu/%255[^/]/%hu", &fwd_port, buf,
458: &fwd_host_port) != 3 &&
459: sscanf(optarg, "%hu:%255[^:]:%hu", &fwd_port, buf,
460: &fwd_host_port) != 3) {
1.31 markus 461: fprintf(stderr, "Bad forwarding specification '%s'.\n", optarg);
462: usage();
463: /* NOTREACHED */
464: }
465: add_remote_forward(&options, fwd_port, buf, fwd_host_port);
466: break;
467: case 'L':
1.37 markus 468: if (sscanf(optarg, "%hu/%255[^/]/%hu", &fwd_port, buf,
469: &fwd_host_port) != 3 &&
470: sscanf(optarg, "%hu:%255[^:]:%hu", &fwd_port, buf,
471: &fwd_host_port) != 3) {
1.31 markus 472: fprintf(stderr, "Bad forwarding specification '%s'.\n", optarg);
473: usage();
474: /* NOTREACHED */
475: }
476: add_local_forward(&options, fwd_port, buf, fwd_host_port);
477: break;
1.108 markus 478:
479: case 'D':
1.109 markus 480: fwd_port = strtol(optarg, &endofnumber, 0);
481: if (optarg == endofnumber) {
482: fprintf(stderr, "Bad port '%s'\n", optarg);
483: exit(1);
484: }
1.108 markus 485: add_local_forward(&options, fwd_port, "socks4", 0);
486: break;
487:
1.31 markus 488: case 'C':
489: options.compression = 1;
490: break;
1.45 markus 491: case 'N':
492: no_shell_flag = 1;
493: no_tty_flag = 1;
494: break;
495: case 'T':
496: no_tty_flag = 1;
497: break;
1.31 markus 498: case 'o':
499: dummy = 1;
500: if (process_config_line(&options, host ? host : "", optarg,
501: "command-line", 0, &dummy) != 0)
502: exit(1);
503: break;
1.85 djm 504: case 's':
505: subsystem_flag = 1;
506: break;
1.31 markus 507: default:
508: usage();
1.1 deraadt 509: }
1.31 markus 510: }
511:
512: /* Check that we got a host name. */
513: if (!host)
514: usage();
515:
1.54 markus 516: SSLeay_add_all_algorithms();
1.72 markus 517: ERR_load_crypto_strings();
1.31 markus 518:
519: /* Initialize the command to execute on remote host. */
520: buffer_init(&command);
1.1 deraadt 521:
1.33 markus 522: /*
523: * Save the command to execute on the remote host in a buffer. There
524: * is no limit on the length of the command, except by the maximum
525: * packet size. Also sets the tty flag if there is no command.
526: */
1.31 markus 527: if (optind == ac) {
528: /* No command specified - execute shell on a tty. */
529: tty_flag = 1;
1.85 djm 530: if (subsystem_flag) {
531: fprintf(stderr, "You must specify a subsystem to invoke.");
532: usage();
533: }
1.31 markus 534: } else {
535: /* A command has been specified. Store it into the
536: buffer. */
537: for (i = optind; i < ac; i++) {
538: if (i > optind)
539: buffer_append(&command, " ", 1);
540: buffer_append(&command, av[i], strlen(av[i]));
541: }
542: }
543:
544: /* Cannot fork to background if no command. */
1.63 markus 545: if (fork_after_authentication_flag && buffer_len(&command) == 0 && !no_shell_flag)
1.31 markus 546: fatal("Cannot fork into background without a command to execute.");
547:
548: /* Allocate a tty by default if no command specified. */
549: if (buffer_len(&command) == 0)
550: tty_flag = 1;
551:
1.75 markus 552: /* Force no tty*/
553: if (no_tty_flag)
554: tty_flag = 0;
1.31 markus 555: /* Do not allocate a tty if stdin is not a tty. */
1.79 markus 556: if (!isatty(fileno(stdin)) && !force_tty_flag) {
1.31 markus 557: if (tty_flag)
1.103 millert 558: log("Pseudo-terminal will not be allocated because stdin is not a terminal.");
1.31 markus 559: tty_flag = 0;
560: }
1.45 markus 561:
1.101 markus 562: /*
563: * Initialize "log" output. Since we are the client all output
564: * actually goes to stderr.
565: */
566: log_init(av[0], SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_USER, 1);
1.31 markus 567:
568: /* Read per-user configuration file. */
1.83 markus 569: snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir, _PATH_SSH_USER_CONFFILE);
1.31 markus 570: read_config_file(buf, host, &options);
571:
572: /* Read systemwide configuration file. */
1.83 markus 573: read_config_file(_PATH_HOST_CONFIG_FILE, host, &options);
1.31 markus 574:
575: /* Fill configuration defaults. */
576: fill_default_options(&options);
577:
578: /* reinit */
1.101 markus 579: log_init(av[0], options.log_level, SYSLOG_FACILITY_USER, 1);
1.31 markus 580:
581: if (options.user == NULL)
582: options.user = xstrdup(pw->pw_name);
583:
584: if (options.hostname != NULL)
585: host = options.hostname;
586:
587: /* Disable rhosts authentication if not running as root. */
588: if (original_effective_uid != 0 || !options.use_privileged_port) {
1.77 markus 589: debug("Rhosts Authentication disabled, "
1.71 markus 590: "originating port will not be trusted.");
1.31 markus 591: options.rhosts_authentication = 0;
592: }
1.33 markus 593: /*
594: * If using rsh has been selected, exec it now (without trying
595: * anything else). Note that we must release privileges first.
596: */
1.31 markus 597: if (options.use_rsh) {
1.33 markus 598: /*
599: * Restore our superuser privileges. This must be done
600: * before permanently setting the uid.
601: */
1.31 markus 602: restore_uid();
603:
604: /* Switch to the original uid permanently. */
1.107 markus 605: permanently_set_uid(pw);
1.31 markus 606:
607: /* Execute rsh. */
608: rsh_connect(host, options.user, &command);
609: fatal("rsh_connect returned");
610: }
611: /* Restore our superuser privileges. */
612: restore_uid();
613:
1.77 markus 614: /* Open a connection to the remote host. */
1.31 markus 615:
616: ok = ssh_connect(host, &hostaddr, options.port,
1.77 markus 617: options.connection_attempts,
618: original_effective_uid != 0 || !options.use_privileged_port,
1.107 markus 619: pw, options.proxy_command);
1.31 markus 620:
1.33 markus 621: /*
622: * If we successfully made the connection, load the host private key
623: * in case we will need it later for combined rsa-rhosts
624: * authentication. This must be done before releasing extra
625: * privileges, because the file is only readable by root.
626: */
1.49 markus 627: if (ok && (options.protocol & SSH_PROTO_1)) {
1.105 markus 628: host_private_key = key_load_private_type(KEY_RSA1,
629: _PATH_HOST_KEY_FILE, "", NULL);
1.31 markus 630: }
1.33 markus 631: /*
632: * Get rid of any extra privileges that we may have. We will no
633: * longer need them. Also, extra privileges could make it very hard
634: * to read identity files and other non-world-readable files from the
635: * user's home directory if it happens to be on a NFS volume where
636: * root is mapped to nobody.
637: */
638:
639: /*
640: * Note that some legacy systems need to postpone the following call
641: * to permanently_set_uid() until the private hostkey is destroyed
642: * with RSA_free(). Otherwise the calling user could ptrace() the
643: * process, read the private hostkey and impersonate the host.
644: * OpenBSD does not allow ptracing of setuid processes.
645: */
1.107 markus 646: permanently_set_uid(pw);
1.31 markus 647:
1.33 markus 648: /*
649: * Now that we are back to our own permissions, create ~/.ssh
650: * directory if it doesn\'t already exist.
651: */
1.83 markus 652: snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir, _PATH_SSH_USER_DIR);
1.31 markus 653: if (stat(buf, &st) < 0)
1.57 djm 654: if (mkdir(buf, 0700) < 0)
1.31 markus 655: error("Could not create directory '%.200s'.", buf);
656:
657: /* Check if the connection failed, and try "rsh" if appropriate. */
658: if (!ok) {
659: if (options.port != 0)
1.35 markus 660: log("Secure connection to %.100s on port %hu refused%.100s.",
1.31 markus 661: host, options.port,
662: options.fallback_to_rsh ? "; reverting to insecure method" : "");
663: else
664: log("Secure connection to %.100s refused%.100s.", host,
665: options.fallback_to_rsh ? "; reverting to insecure method" : "");
666:
667: if (options.fallback_to_rsh) {
668: rsh_connect(host, options.user, &command);
669: fatal("rsh_connect returned");
670: }
671: exit(1);
672: }
1.104 markus 673: /* load options.identity_files */
674: load_public_identity_files();
675:
676: /* Expand ~ in known host file names. */
677: /* XXX mem-leaks: */
1.72 markus 678: options.system_hostfile =
679: tilde_expand_filename(options.system_hostfile, original_real_uid);
680: options.user_hostfile =
681: tilde_expand_filename(options.user_hostfile, original_real_uid);
682: options.system_hostfile2 =
683: tilde_expand_filename(options.system_hostfile2, original_real_uid);
684: options.user_hostfile2 =
685: tilde_expand_filename(options.user_hostfile2, original_real_uid);
1.31 markus 686:
687: /* Log into the remote system. This never returns if the login fails. */
1.107 markus 688: ssh_login(host_private_key, host, (struct sockaddr *)&hostaddr, pw);
1.31 markus 689:
690: /* We no longer need the host private key. Clear it now. */
1.105 markus 691: if (host_private_key != NULL)
692: key_free(host_private_key); /* Destroys contents safely */
1.31 markus 693:
1.45 markus 694: exit_status = compat20 ? ssh_session2() : ssh_session();
695: packet_close();
696: return exit_status;
697: }
698:
1.50 markus 699: void
700: x11_get_proto(char *proto, int proto_len, char *data, int data_len)
701: {
702: char line[512];
703: FILE *f;
704: int got_data = 0, i;
705:
1.55 markus 706: if (options.xauth_location) {
707: /* Try to get Xauthority information for the display. */
1.93 itojun 708: snprintf(line, sizeof line, "%.100s list %.200s 2>" _PATH_DEVNULL,
1.55 markus 709: options.xauth_location, getenv("DISPLAY"));
710: f = popen(line, "r");
711: if (f && fgets(line, sizeof(line), f) &&
712: sscanf(line, "%*s %s %s", proto, data) == 2)
713: got_data = 1;
714: if (f)
715: pclose(f);
716: }
1.50 markus 717: /*
718: * If we didn't get authentication data, just make up some
719: * data. The forwarding code will check the validity of the
720: * response anyway, and substitute this data. The X11
721: * server, however, will ignore this fake data and use
722: * whatever authentication mechanisms it was using otherwise
723: * for the local connection.
724: */
725: if (!got_data) {
726: u_int32_t rand = 0;
727:
728: strlcpy(proto, "MIT-MAGIC-COOKIE-1", proto_len);
729: for (i = 0; i < 16; i++) {
730: if (i % 4 == 0)
731: rand = arc4random();
732: snprintf(data + 2 * i, data_len - 2 * i, "%02x", rand & 0xff);
733: rand >>= 8;
734: }
735: }
736: }
737:
1.70 markus 738: void
739: ssh_init_forwarding(void)
740: {
1.86 markus 741: int success = 0;
1.70 markus 742: int i;
1.86 markus 743:
1.70 markus 744: /* Initiate local TCP/IP port forwardings. */
745: for (i = 0; i < options.num_local_forwards; i++) {
746: debug("Connections to local port %d forwarded to remote address %.200s:%d",
747: options.local_forwards[i].port,
748: options.local_forwards[i].host,
749: options.local_forwards[i].host_port);
1.86 markus 750: success += channel_request_local_forwarding(
1.70 markus 751: options.local_forwards[i].port,
752: options.local_forwards[i].host,
753: options.local_forwards[i].host_port,
754: options.gateway_ports);
755: }
1.86 markus 756: if (i > 0 && success == 0)
757: error("Could not request local forwarding.");
1.70 markus 758:
759: /* Initiate remote TCP/IP port forwardings. */
760: for (i = 0; i < options.num_remote_forwards; i++) {
761: debug("Connections to remote port %d forwarded to local address %.200s:%d",
762: options.remote_forwards[i].port,
763: options.remote_forwards[i].host,
764: options.remote_forwards[i].host_port);
765: channel_request_remote_forwarding(
766: options.remote_forwards[i].port,
767: options.remote_forwards[i].host,
768: options.remote_forwards[i].host_port);
769: }
770: }
771:
772: void
773: check_agent_present(void)
774: {
775: if (options.forward_agent) {
776: /* Clear agent forwarding if we don\'t have an agent. */
777: int authfd = ssh_get_authentication_socket();
778: if (authfd < 0)
779: options.forward_agent = 0;
780: else
781: ssh_close_authentication_socket(authfd);
782: }
783: }
784:
1.45 markus 785: int
786: ssh_session(void)
787: {
788: int type;
789: int plen;
790: int interactive = 0;
791: int have_tty = 0;
792: struct winsize ws;
793: char *cp;
794:
1.31 markus 795: /* Enable compression if requested. */
796: if (options.compression) {
797: debug("Requesting compression at level %d.", options.compression_level);
798:
799: if (options.compression_level < 1 || options.compression_level > 9)
800: fatal("Compression level must be from 1 (fast) to 9 (slow, best).");
801:
802: /* Send the request. */
803: packet_start(SSH_CMSG_REQUEST_COMPRESSION);
804: packet_put_int(options.compression_level);
805: packet_send();
806: packet_write_wait();
807: type = packet_read(&plen);
808: if (type == SSH_SMSG_SUCCESS)
809: packet_start_compression(options.compression_level);
810: else if (type == SSH_SMSG_FAILURE)
811: log("Warning: Remote host refused compression.");
812: else
813: packet_disconnect("Protocol error waiting for compression response.");
814: }
815: /* Allocate a pseudo tty if appropriate. */
816: if (tty_flag) {
817: debug("Requesting pty.");
818:
819: /* Start the packet. */
820: packet_start(SSH_CMSG_REQUEST_PTY);
821:
822: /* Store TERM in the packet. There is no limit on the
823: length of the string. */
824: cp = getenv("TERM");
825: if (!cp)
826: cp = "";
827: packet_put_string(cp, strlen(cp));
828:
829: /* Store window size in the packet. */
830: if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
831: memset(&ws, 0, sizeof(ws));
832: packet_put_int(ws.ws_row);
833: packet_put_int(ws.ws_col);
834: packet_put_int(ws.ws_xpixel);
835: packet_put_int(ws.ws_ypixel);
836:
837: /* Store tty modes in the packet. */
838: tty_make_modes(fileno(stdin));
839:
840: /* Send the packet, and wait for it to leave. */
841: packet_send();
842: packet_write_wait();
843:
844: /* Read response from the server. */
845: type = packet_read(&plen);
1.43 markus 846: if (type == SSH_SMSG_SUCCESS) {
1.31 markus 847: interactive = 1;
1.45 markus 848: have_tty = 1;
1.43 markus 849: } else if (type == SSH_SMSG_FAILURE)
1.31 markus 850: log("Warning: Remote host failed or refused to allocate a pseudo tty.");
851: else
852: packet_disconnect("Protocol error waiting for pty request response.");
853: }
854: /* Request X11 forwarding if enabled and DISPLAY is set. */
855: if (options.forward_x11 && getenv("DISPLAY") != NULL) {
1.50 markus 856: char proto[512], data[512];
857: /* Get reasonable local authentication information. */
858: x11_get_proto(proto, sizeof proto, data, sizeof data);
859: /* Request forwarding with authentication spoofing. */
1.31 markus 860: debug("Requesting X11 forwarding with authentication spoofing.");
1.50 markus 861: x11_request_forwarding_with_spoofing(0, proto, data);
1.31 markus 862:
863: /* Read response from the server. */
864: type = packet_read(&plen);
865: if (type == SSH_SMSG_SUCCESS) {
866: interactive = 1;
1.50 markus 867: } else if (type == SSH_SMSG_FAILURE) {
1.31 markus 868: log("Warning: Remote host denied X11 forwarding.");
1.50 markus 869: } else {
1.31 markus 870: packet_disconnect("Protocol error waiting for X11 forwarding");
1.50 markus 871: }
1.31 markus 872: }
873: /* Tell the packet module whether this is an interactive session. */
1.80 markus 874: packet_set_interactive(interactive);
1.31 markus 875:
876: /* Request authentication agent forwarding if appropriate. */
1.70 markus 877: check_agent_present();
878:
1.31 markus 879: if (options.forward_agent) {
880: debug("Requesting authentication agent forwarding.");
881: auth_request_forwarding();
882:
883: /* Read response from the server. */
884: type = packet_read(&plen);
885: packet_integrity_check(plen, 0, type);
886: if (type != SSH_SMSG_SUCCESS)
887: log("Warning: Remote host denied authentication agent forwarding.");
888: }
889:
1.70 markus 890: /* Initiate port forwardings. */
891: ssh_init_forwarding();
1.34 markus 892:
893: /* If requested, let ssh continue in the background. */
1.48 markus 894: if (fork_after_authentication_flag)
1.34 markus 895: if (daemon(1, 1) < 0)
896: fatal("daemon() failed: %.200s", strerror(errno));
1.31 markus 897:
1.33 markus 898: /*
899: * If a command was specified on the command line, execute the
900: * command now. Otherwise request the server to start a shell.
901: */
1.31 markus 902: if (buffer_len(&command) > 0) {
903: int len = buffer_len(&command);
904: if (len > 900)
905: len = 900;
906: debug("Sending command: %.*s", len, buffer_ptr(&command));
907: packet_start(SSH_CMSG_EXEC_CMD);
908: packet_put_string(buffer_ptr(&command), buffer_len(&command));
909: packet_send();
910: packet_write_wait();
911: } else {
912: debug("Requesting shell.");
913: packet_start(SSH_CMSG_EXEC_SHELL);
914: packet_send();
915: packet_write_wait();
916: }
917:
918: /* Enter the interactive session. */
1.60 markus 919: return client_loop(have_tty, tty_flag ? options.escape_char : -1, 0);
1.45 markus 920: }
921:
922: void
1.89 markus 923: client_subsystem_reply(int type, int plen, void *ctxt)
924: {
925: int id, len;
926:
927: id = packet_get_int();
928: len = buffer_len(&command);
1.100 markus 929: if (len > 900)
930: len = 900;
1.89 markus 931: packet_done();
932: if (type == SSH2_MSG_CHANNEL_FAILURE)
933: fatal("Request for subsystem '%.*s' failed on channel %d",
934: len, buffer_ptr(&command), id);
935: }
936:
937: void
1.70 markus 938: ssh_session2_callback(int id, void *arg)
1.45 markus 939: {
940: int len;
1.80 markus 941: int interactive = 0;
942:
1.87 deraadt 943: debug("client_init id %d arg %ld", id, (long)arg);
1.31 markus 944:
1.45 markus 945: if (tty_flag) {
946: struct winsize ws;
947: char *cp;
948: cp = getenv("TERM");
949: if (!cp)
950: cp = "";
951: /* Store window size in the packet. */
952: if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
953: memset(&ws, 0, sizeof(ws));
954:
955: channel_request_start(id, "pty-req", 0);
956: packet_put_cstring(cp);
957: packet_put_int(ws.ws_col);
958: packet_put_int(ws.ws_row);
959: packet_put_int(ws.ws_xpixel);
960: packet_put_int(ws.ws_ypixel);
961: packet_put_cstring(""); /* XXX: encode terminal modes */
962: packet_send();
1.80 markus 963: interactive = 1;
1.45 markus 964: /* XXX wait for reply */
965: }
1.50 markus 966: if (options.forward_x11 &&
967: getenv("DISPLAY") != NULL) {
968: char proto[512], data[512];
969: /* Get reasonable local authentication information. */
970: x11_get_proto(proto, sizeof proto, data, sizeof data);
971: /* Request forwarding with authentication spoofing. */
972: debug("Requesting X11 forwarding with authentication spoofing.");
973: x11_request_forwarding_with_spoofing(id, proto, data);
1.80 markus 974: interactive = 1;
1.50 markus 975: /* XXX wait for reply */
976: }
977:
1.70 markus 978: check_agent_present();
979: if (options.forward_agent) {
980: debug("Requesting authentication agent forwarding.");
981: channel_request_start(id, "auth-agent-req@openssh.com", 0);
982: packet_send();
983: }
984:
1.45 markus 985: len = buffer_len(&command);
986: if (len > 0) {
987: if (len > 900)
988: len = 900;
1.85 djm 989: if (subsystem_flag) {
990: debug("Sending subsystem: %.*s", len, buffer_ptr(&command));
1.89 markus 991: channel_request_start(id, "subsystem", /*want reply*/ 1);
992: /* register callback for reply */
993: /* XXX we asume that client_loop has already been called */
994: dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &client_subsystem_reply);
995: dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &client_subsystem_reply);
1.85 djm 996: } else {
997: debug("Sending command: %.*s", len, buffer_ptr(&command));
998: channel_request_start(id, "exec", 0);
999: }
1.100 markus 1000: packet_put_string(buffer_ptr(&command), buffer_len(&command));
1.45 markus 1001: packet_send();
1002: } else {
1003: channel_request(id, "shell", 0);
1004: }
1005: /* channel_callback(id, SSH2_MSG_OPEN_CONFIGMATION, client_init, 0); */
1.90 markus 1006:
1.45 markus 1007: /* register different callback, etc. XXX */
1.80 markus 1008: packet_set_interactive(interactive);
1.45 markus 1009: }
1010:
1011: int
1.106 markus 1012: ssh_session2_command(void)
1.45 markus 1013: {
1.106 markus 1014: int id, window, packetmax;
1.60 markus 1015: int in, out, err;
1016:
1.62 markus 1017: if (stdin_null_flag) {
1.93 itojun 1018: in = open(_PATH_DEVNULL, O_RDONLY);
1.62 markus 1019: } else {
1020: in = dup(STDIN_FILENO);
1021: }
1.60 markus 1022: out = dup(STDOUT_FILENO);
1023: err = dup(STDERR_FILENO);
1.45 markus 1024:
1025: if (in < 0 || out < 0 || err < 0)
1.62 markus 1026: fatal("dup() in/out/err failed");
1.45 markus 1027:
1.69 markus 1028: /* enable nonblocking unless tty */
1029: if (!isatty(in))
1030: set_nonblock(in);
1031: if (!isatty(out))
1032: set_nonblock(out);
1033: if (!isatty(err))
1034: set_nonblock(err);
1035:
1.65 markus 1036: window = CHAN_SES_WINDOW_DEFAULT;
1037: packetmax = CHAN_SES_PACKET_DEFAULT;
1038: if (!tty_flag) {
1.45 markus 1039: window *= 2;
1.65 markus 1040: packetmax *=2;
1.45 markus 1041: }
1042: id = channel_new(
1043: "session", SSH_CHANNEL_OPENING, in, out, err,
1.65 markus 1044: window, packetmax, CHAN_EXTENDED_WRITE,
1.69 markus 1045: xstrdup("client-session"), /*nonblock*/0);
1.45 markus 1046:
1.106 markus 1047: debug("channel_new: %d", id);
1048:
1.45 markus 1049: channel_open(id);
1.70 markus 1050: channel_register_callback(id, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION,
1051: ssh_session2_callback, (void *)0);
1.106 markus 1052:
1053: return id;
1054: }
1055:
1056: int
1057: ssh_session2(void)
1058: {
1059: int id;
1060:
1061: /* XXX should be pre-session */
1062: ssh_init_forwarding();
1063:
1064: id = no_shell_flag ? -1 : ssh_session2_command();
1065:
1066: /* If requested, let ssh continue in the background. */
1067: if (fork_after_authentication_flag)
1068: if (daemon(1, 1) < 0)
1069: fatal("daemon() failed: %.200s", strerror(errno));
1.31 markus 1070:
1.60 markus 1071: return client_loop(tty_flag, tty_flag ? options.escape_char : -1, id);
1.72 markus 1072: }
1073:
1.104 markus 1074: void
1075: load_public_identity_files(void)
1076: {
1077: char *filename;
1078: Key *public;
1079: int i;
1080:
1081: for (i = 0; i < options.num_identity_files; i++) {
1082: filename = tilde_expand_filename(options.identity_files[i],
1083: original_real_uid);
1.105 markus 1084: public = key_load_public(filename, NULL);
1.104 markus 1085: debug("identity file %s type %d", filename,
1086: public ? public->type : -1);
1087: xfree(options.identity_files[i]);
1088: options.identity_files[i] = filename;
1089: options.identity_keys[i] = public;
1090: }
1.1 deraadt 1091: }