Annotation of src/usr.bin/ssh/ssh.c, Revision 1.125
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"
1.125 ! markus 42: RCSID("$OpenBSD: ssh.c,v 1.124 2001/06/07 20:23:05 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"
1.123 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"
1.115 stevesk 70: #include "sshtty.h"
1.49 markus 71:
72: extern char *__progname;
1.1 deraadt 73:
1.37 markus 74: /* Flag indicating whether IPv4 or IPv6. This can be set on the command line.
75: Default value is AF_UNSPEC means both IPv4 and IPv6. */
76: int IPv4or6 = AF_UNSPEC;
77:
1.31 markus 78: /* Flag indicating whether debug mode is on. This can be set on the command line. */
1.1 deraadt 79: int debug_flag = 0;
80:
1.46 markus 81: /* Flag indicating whether a tty should be allocated */
1.1 deraadt 82: int tty_flag = 0;
1.79 markus 83: int no_tty_flag = 0;
84: int force_tty_flag = 0;
1.1 deraadt 85:
1.45 markus 86: /* don't exec a shell */
87: int no_shell_flag = 0;
88:
1.33 markus 89: /*
90: * Flag indicating that nothing should be read from stdin. This can be set
91: * on the command line.
92: */
1.1 deraadt 93: int stdin_null_flag = 0;
94:
1.33 markus 95: /*
96: * Flag indicating that ssh should fork after authentication. This is useful
97: * so that the pasphrase can be entered manually, and then ssh goes to the
98: * background.
99: */
1.1 deraadt 100: int fork_after_authentication_flag = 0;
101:
1.33 markus 102: /*
103: * General data structure for command line options and options configurable
104: * in configuration files. See readconf.h.
105: */
1.1 deraadt 106: Options options;
107:
1.33 markus 108: /*
109: * Name of the host we are connecting to. This is the name given on the
110: * command line, or the HostName specified for the user-supplied name in a
111: * configuration file.
112: */
1.1 deraadt 113: char *host;
114:
1.22 provos 115: /* socket address the host resolves to */
1.37 markus 116: struct sockaddr_storage hostaddr;
1.22 provos 117:
1.33 markus 118: /*
119: * Flag to indicate that we have received a window change signal which has
120: * not yet been processed. This will cause a message indicating the new
121: * window size to be sent to the server a little later. This is volatile
122: * because this is updated in a signal handler.
123: */
1.1 deraadt 124: volatile int received_window_change_signal = 0;
125:
1.112 markus 126: /* Private host keys. */
127: struct {
128: Key **keys;
129: int nkeys;
130: } sensitive_data;
1.1 deraadt 131:
1.10 dugsong 132: /* Original real UID. */
133: uid_t original_real_uid;
1.1 deraadt 134:
1.45 markus 135: /* command to be executed */
136: Buffer command;
137:
1.85 djm 138: /* Should we execute a command or invoke a subsystem? */
139: int subsystem_flag = 0;
140:
1.1 deraadt 141: /* Prints a help message to the user. This function never returns. */
142:
1.2 provos 143: void
1.93 itojun 144: usage(void)
1.1 deraadt 145: {
1.76 markus 146: fprintf(stderr, "Usage: %s [options] host [command]\n", __progname);
1.31 markus 147: fprintf(stderr, "Options:\n");
148: fprintf(stderr, " -l user Log in using this user name.\n");
1.93 itojun 149: fprintf(stderr, " -n Redirect input from " _PATH_DEVNULL ".\n");
1.53 markus 150: fprintf(stderr, " -A Enable authentication agent forwarding.\n");
1.120 markus 151: fprintf(stderr, " -a Disable authentication agent forwarding (default).\n");
1.9 dugsong 152: #ifdef AFS
1.31 markus 153: fprintf(stderr, " -k Disable Kerberos ticket and AFS token forwarding.\n");
154: #endif /* AFS */
1.88 stevesk 155: fprintf(stderr, " -X Enable X11 connection forwarding.\n");
1.120 markus 156: fprintf(stderr, " -x Disable X11 connection forwarding (default).\n");
1.99 deraadt 157: fprintf(stderr, " -i file Identity for public key authentication "
158: "(default: ~/.ssh/identity)\n");
1.31 markus 159: fprintf(stderr, " -t Tty; allocate a tty even if command is given.\n");
1.45 markus 160: fprintf(stderr, " -T Do not allocate a tty.\n");
1.31 markus 161: fprintf(stderr, " -v Verbose; display verbose debugging messages.\n");
1.66 markus 162: fprintf(stderr, " Multiple -v increases verbosity.\n");
1.31 markus 163: fprintf(stderr, " -V Display version number only.\n");
164: fprintf(stderr, " -P Don't allocate a privileged port.\n");
165: fprintf(stderr, " -q Quiet; don't display any warning messages.\n");
166: fprintf(stderr, " -f Fork into background after authentication.\n");
167: fprintf(stderr, " -e char Set escape character; ``none'' = disable (default: ~).\n");
168:
1.120 markus 169: fprintf(stderr, " -c cipher Select encryption algorithm\n");
1.102 stevesk 170: fprintf(stderr, " -m macs Specify MAC algorithms for protocol version 2.\n");
1.31 markus 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");
1.120 markus 185: fprintf(stderr, " -b addr Local IP address.\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;
1.125 ! markus 239: char *optarg, *p, *cp, 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;
1.125 ! markus 295: if (strchr(av[optind], '@')) {
! 296: p = xstrdup(av[optind]);
! 297: cp = strchr(p, '@');
! 298: if(cp == NULL || cp == p)
1.48 markus 299: usage();
1.125 ! markus 300: options.user = p;
1.31 markus 301: *cp = '\0';
302: host = ++cp;
303: } else
304: host = av[optind];
305: continue;
306: }
307: opt = av[optind][1];
308: if (!opt)
309: usage();
1.117 markus 310: if (strchr("eilcmpbLRDo", opt)) { /* options with arguments */
1.31 markus 311: optarg = av[optind] + 2;
312: if (strcmp(optarg, "") == 0) {
313: if (optind >= ac - 1)
314: usage();
315: optarg = av[++optind];
316: }
317: } else {
318: if (av[optind][2])
319: usage();
320: optarg = NULL;
321: }
322: switch (opt) {
1.91 jakob 323: case '1':
324: options.protocol = SSH_PROTO_1;
325: break;
1.47 markus 326: case '2':
327: options.protocol = SSH_PROTO_2;
328: break;
1.37 markus 329: case '4':
330: IPv4or6 = AF_INET;
331: break;
332: case '6':
333: IPv4or6 = AF_INET6;
334: break;
1.31 markus 335: case 'n':
336: stdin_null_flag = 1;
337: break;
338: case 'f':
339: fork_after_authentication_flag = 1;
340: stdin_null_flag = 1;
341: break;
342: case 'x':
343: options.forward_x11 = 0;
344: break;
345: case 'X':
346: options.forward_x11 = 1;
347: break;
348: case 'g':
349: options.gateway_ports = 1;
350: break;
351: case 'P':
352: options.use_privileged_port = 0;
353: break;
354: case 'a':
355: options.forward_agent = 0;
1.53 markus 356: break;
357: case 'A':
358: options.forward_agent = 1;
1.31 markus 359: break;
1.9 dugsong 360: #ifdef AFS
1.31 markus 361: case 'k':
362: options.kerberos_tgt_passing = 0;
363: options.afs_token_passing = 0;
364: break;
1.1 deraadt 365: #endif
1.31 markus 366: case 'i':
367: if (stat(optarg, &st) < 0) {
368: fprintf(stderr, "Warning: Identity file %s does not exist.\n",
1.72 markus 369: optarg);
1.31 markus 370: break;
371: }
372: if (options.num_identity_files >= SSH_MAX_IDENTITY_FILES)
373: fatal("Too many identity files specified (max %d)",
1.72 markus 374: SSH_MAX_IDENTITY_FILES);
375: options.identity_files[options.num_identity_files++] = xstrdup(optarg);
1.31 markus 376: break;
377: case 't':
1.79 markus 378: if (tty_flag)
379: force_tty_flag = 1;
1.31 markus 380: tty_flag = 1;
381: break;
382: case 'v':
1.66 markus 383: if (0 == debug_flag) {
384: debug_flag = 1;
385: options.log_level = SYSLOG_LEVEL_DEBUG1;
386: } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) {
387: options.log_level++;
388: break;
389: } else {
1.103 millert 390: fatal("Too high debugging level.");
1.66 markus 391: }
392: /* fallthrough */
1.31 markus 393: case 'V':
1.96 deraadt 394: fprintf(stderr,
395: "%s, SSH protocols %d.%d/%d.%d, OpenSSL 0x%8.8lx\n",
1.46 markus 396: SSH_VERSION,
397: PROTOCOL_MAJOR_1, PROTOCOL_MINOR_1,
1.96 deraadt 398: PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2,
399: SSLeay());
1.31 markus 400: if (opt == 'V')
401: exit(0);
402: break;
403: case 'q':
404: options.log_level = SYSLOG_LEVEL_QUIET;
405: break;
406: case 'e':
407: if (optarg[0] == '^' && optarg[2] == 0 &&
1.78 markus 408: (u_char) optarg[1] >= 64 && (u_char) optarg[1] < 128)
409: options.escape_char = (u_char) optarg[1] & 31;
1.31 markus 410: else if (strlen(optarg) == 1)
1.78 markus 411: options.escape_char = (u_char) optarg[0];
1.31 markus 412: else if (strcmp(optarg, "none") == 0)
1.119 stevesk 413: options.escape_char = SSH_ESCAPECHAR_NONE;
1.31 markus 414: else {
415: fprintf(stderr, "Bad escape character '%s'.\n", optarg);
416: exit(1);
417: }
418: break;
419: case 'c':
1.49 markus 420: if (ciphers_valid(optarg)) {
421: /* SSH2 only */
422: options.ciphers = xstrdup(optarg);
1.51 markus 423: options.cipher = SSH_CIPHER_ILLEGAL;
1.49 markus 424: } else {
425: /* SSH1 only */
1.74 markus 426: options.cipher = cipher_number(optarg);
427: if (options.cipher == -1) {
1.49 markus 428: fprintf(stderr, "Unknown cipher type '%s'\n", optarg);
429: exit(1);
430: }
1.74 markus 431: if (options.cipher == SSH_CIPHER_3DES) {
432: options.ciphers = "3des-cbc";
433: } else if (options.cipher == SSH_CIPHER_BLOWFISH) {
434: options.ciphers = "blowfish-cbc";
435: } else {
436: options.ciphers = (char *)-1;
437: }
1.95 markus 438: }
439: break;
440: case 'm':
441: if (mac_valid(optarg))
442: options.macs = xstrdup(optarg);
443: else {
444: fprintf(stderr, "Unknown mac type '%s'\n", optarg);
445: exit(1);
1.31 markus 446: }
447: break;
448: case 'p':
1.113 stevesk 449: options.port = a2port(optarg);
450: if (options.port == 0) {
1.109 markus 451: fprintf(stderr, "Bad port '%s'\n", optarg);
452: exit(1);
453: }
1.31 markus 454: break;
455: case 'l':
456: options.user = optarg;
457: break;
458: case 'R':
1.37 markus 459: if (sscanf(optarg, "%hu/%255[^/]/%hu", &fwd_port, buf,
460: &fwd_host_port) != 3 &&
461: sscanf(optarg, "%hu:%255[^:]:%hu", &fwd_port, buf,
462: &fwd_host_port) != 3) {
1.31 markus 463: fprintf(stderr, "Bad forwarding specification '%s'.\n", optarg);
464: usage();
465: /* NOTREACHED */
466: }
467: add_remote_forward(&options, fwd_port, buf, fwd_host_port);
468: break;
469: case 'L':
1.37 markus 470: if (sscanf(optarg, "%hu/%255[^/]/%hu", &fwd_port, buf,
471: &fwd_host_port) != 3 &&
472: sscanf(optarg, "%hu:%255[^:]:%hu", &fwd_port, buf,
473: &fwd_host_port) != 3) {
1.31 markus 474: fprintf(stderr, "Bad forwarding specification '%s'.\n", optarg);
475: usage();
476: /* NOTREACHED */
477: }
478: add_local_forward(&options, fwd_port, buf, fwd_host_port);
479: break;
1.108 markus 480:
481: case 'D':
1.113 stevesk 482: fwd_port = a2port(optarg);
483: if (fwd_port == 0) {
484: fprintf(stderr, "Bad dynamic port '%s'\n", optarg);
1.109 markus 485: exit(1);
486: }
1.108 markus 487: add_local_forward(&options, fwd_port, "socks4", 0);
488: break;
489:
1.31 markus 490: case 'C':
491: options.compression = 1;
492: break;
1.45 markus 493: case 'N':
494: no_shell_flag = 1;
495: no_tty_flag = 1;
496: break;
497: case 'T':
498: no_tty_flag = 1;
499: break;
1.31 markus 500: case 'o':
501: dummy = 1;
502: if (process_config_line(&options, host ? host : "", optarg,
503: "command-line", 0, &dummy) != 0)
504: exit(1);
505: break;
1.85 djm 506: case 's':
507: subsystem_flag = 1;
1.117 markus 508: break;
509: case 'b':
510: options.bind_address = optarg;
1.85 djm 511: break;
1.31 markus 512: default:
513: usage();
1.1 deraadt 514: }
1.31 markus 515: }
516:
517: /* Check that we got a host name. */
518: if (!host)
519: usage();
520:
1.54 markus 521: SSLeay_add_all_algorithms();
1.72 markus 522: ERR_load_crypto_strings();
1.31 markus 523:
524: /* Initialize the command to execute on remote host. */
525: buffer_init(&command);
1.1 deraadt 526:
1.33 markus 527: /*
528: * Save the command to execute on the remote host in a buffer. There
529: * is no limit on the length of the command, except by the maximum
530: * packet size. Also sets the tty flag if there is no command.
531: */
1.31 markus 532: if (optind == ac) {
533: /* No command specified - execute shell on a tty. */
534: tty_flag = 1;
1.85 djm 535: if (subsystem_flag) {
1.114 stevesk 536: fprintf(stderr, "You must specify a subsystem to invoke.\n");
1.85 djm 537: usage();
538: }
1.31 markus 539: } else {
540: /* A command has been specified. Store it into the
541: buffer. */
542: for (i = optind; i < ac; i++) {
543: if (i > optind)
544: buffer_append(&command, " ", 1);
545: buffer_append(&command, av[i], strlen(av[i]));
546: }
547: }
548:
549: /* Cannot fork to background if no command. */
1.63 markus 550: if (fork_after_authentication_flag && buffer_len(&command) == 0 && !no_shell_flag)
1.31 markus 551: fatal("Cannot fork into background without a command to execute.");
552:
553: /* Allocate a tty by default if no command specified. */
554: if (buffer_len(&command) == 0)
555: tty_flag = 1;
556:
1.75 markus 557: /* Force no tty*/
558: if (no_tty_flag)
559: tty_flag = 0;
1.31 markus 560: /* Do not allocate a tty if stdin is not a tty. */
1.79 markus 561: if (!isatty(fileno(stdin)) && !force_tty_flag) {
1.31 markus 562: if (tty_flag)
1.103 millert 563: log("Pseudo-terminal will not be allocated because stdin is not a terminal.");
1.31 markus 564: tty_flag = 0;
565: }
1.45 markus 566:
1.101 markus 567: /*
568: * Initialize "log" output. Since we are the client all output
569: * actually goes to stderr.
570: */
1.111 markus 571: log_init(av[0], options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level,
572: SYSLOG_FACILITY_USER, 1);
1.31 markus 573:
574: /* Read per-user configuration file. */
1.83 markus 575: snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir, _PATH_SSH_USER_CONFFILE);
1.31 markus 576: read_config_file(buf, host, &options);
577:
578: /* Read systemwide configuration file. */
1.83 markus 579: read_config_file(_PATH_HOST_CONFIG_FILE, host, &options);
1.31 markus 580:
581: /* Fill configuration defaults. */
582: fill_default_options(&options);
583:
584: /* reinit */
1.101 markus 585: log_init(av[0], options.log_level, SYSLOG_FACILITY_USER, 1);
1.31 markus 586:
587: if (options.user == NULL)
588: options.user = xstrdup(pw->pw_name);
589:
590: if (options.hostname != NULL)
591: host = options.hostname;
592:
593: /* Disable rhosts authentication if not running as root. */
594: if (original_effective_uid != 0 || !options.use_privileged_port) {
1.77 markus 595: debug("Rhosts Authentication disabled, "
1.71 markus 596: "originating port will not be trusted.");
1.31 markus 597: options.rhosts_authentication = 0;
598: }
1.33 markus 599: /*
600: * If using rsh has been selected, exec it now (without trying
601: * anything else). Note that we must release privileges first.
602: */
1.31 markus 603: if (options.use_rsh) {
1.33 markus 604: /*
605: * Restore our superuser privileges. This must be done
606: * before permanently setting the uid.
607: */
1.31 markus 608: restore_uid();
609:
610: /* Switch to the original uid permanently. */
1.107 markus 611: permanently_set_uid(pw);
1.31 markus 612:
613: /* Execute rsh. */
614: rsh_connect(host, options.user, &command);
615: fatal("rsh_connect returned");
616: }
617: /* Restore our superuser privileges. */
618: restore_uid();
619:
1.77 markus 620: /* Open a connection to the remote host. */
1.31 markus 621:
622: ok = ssh_connect(host, &hostaddr, options.port,
1.77 markus 623: options.connection_attempts,
624: original_effective_uid != 0 || !options.use_privileged_port,
1.107 markus 625: pw, options.proxy_command);
1.31 markus 626:
1.33 markus 627: /*
628: * If we successfully made the connection, load the host private key
629: * in case we will need it later for combined rsa-rhosts
630: * authentication. This must be done before releasing extra
631: * privileges, because the file is only readable by root.
632: */
1.112 markus 633: sensitive_data.nkeys = 0;
634: sensitive_data.keys = NULL;
635: if (ok && (options.rhosts_rsa_authentication ||
636: options.hostbased_authentication)) {
637: sensitive_data.nkeys = 3;
638: sensitive_data.keys = xmalloc(sensitive_data.nkeys*sizeof(Key));
639: sensitive_data.keys[0] = key_load_private_type(KEY_RSA1,
1.105 markus 640: _PATH_HOST_KEY_FILE, "", NULL);
1.112 markus 641: sensitive_data.keys[1] = key_load_private_type(KEY_DSA,
642: _PATH_HOST_DSA_KEY_FILE, "", NULL);
643: sensitive_data.keys[2] = key_load_private_type(KEY_RSA,
644: _PATH_HOST_RSA_KEY_FILE, "", NULL);
1.31 markus 645: }
1.33 markus 646: /*
647: * Get rid of any extra privileges that we may have. We will no
648: * longer need them. Also, extra privileges could make it very hard
649: * to read identity files and other non-world-readable files from the
650: * user's home directory if it happens to be on a NFS volume where
651: * root is mapped to nobody.
652: */
653:
654: /*
655: * Note that some legacy systems need to postpone the following call
656: * to permanently_set_uid() until the private hostkey is destroyed
657: * with RSA_free(). Otherwise the calling user could ptrace() the
658: * process, read the private hostkey and impersonate the host.
659: * OpenBSD does not allow ptracing of setuid processes.
660: */
1.107 markus 661: permanently_set_uid(pw);
1.31 markus 662:
1.33 markus 663: /*
664: * Now that we are back to our own permissions, create ~/.ssh
665: * directory if it doesn\'t already exist.
666: */
1.83 markus 667: snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir, _PATH_SSH_USER_DIR);
1.31 markus 668: if (stat(buf, &st) < 0)
1.57 djm 669: if (mkdir(buf, 0700) < 0)
1.31 markus 670: error("Could not create directory '%.200s'.", buf);
671:
672: /* Check if the connection failed, and try "rsh" if appropriate. */
673: if (!ok) {
674: if (options.port != 0)
1.35 markus 675: log("Secure connection to %.100s on port %hu refused%.100s.",
1.31 markus 676: host, options.port,
677: options.fallback_to_rsh ? "; reverting to insecure method" : "");
678: else
679: log("Secure connection to %.100s refused%.100s.", host,
680: options.fallback_to_rsh ? "; reverting to insecure method" : "");
681:
682: if (options.fallback_to_rsh) {
683: rsh_connect(host, options.user, &command);
684: fatal("rsh_connect returned");
685: }
686: exit(1);
687: }
1.104 markus 688: /* load options.identity_files */
689: load_public_identity_files();
690:
691: /* Expand ~ in known host file names. */
692: /* XXX mem-leaks: */
1.72 markus 693: options.system_hostfile =
694: tilde_expand_filename(options.system_hostfile, original_real_uid);
695: options.user_hostfile =
696: tilde_expand_filename(options.user_hostfile, original_real_uid);
697: options.system_hostfile2 =
698: tilde_expand_filename(options.system_hostfile2, original_real_uid);
699: options.user_hostfile2 =
700: tilde_expand_filename(options.user_hostfile2, original_real_uid);
1.31 markus 701:
702: /* Log into the remote system. This never returns if the login fails. */
1.112 markus 703: ssh_login(sensitive_data.keys, sensitive_data.nkeys,
704: host, (struct sockaddr *)&hostaddr, pw);
1.31 markus 705:
1.112 markus 706: /* We no longer need the private host keys. Clear them now. */
707: if (sensitive_data.nkeys != 0) {
708: for (i = 0; i < sensitive_data.nkeys; i++) {
709: if (sensitive_data.keys[i] != NULL) {
710: /* Destroys contents safely */
711: debug3("clear hostkey %d", i);
712: key_free(sensitive_data.keys[i]);
713: sensitive_data.keys[i] = NULL;
714: }
715: }
716: xfree(sensitive_data.keys);
717: }
1.31 markus 718:
1.45 markus 719: exit_status = compat20 ? ssh_session2() : ssh_session();
720: packet_close();
721: return exit_status;
722: }
723:
1.50 markus 724: void
725: x11_get_proto(char *proto, int proto_len, char *data, int data_len)
726: {
727: char line[512];
728: FILE *f;
729: int got_data = 0, i;
730:
1.55 markus 731: if (options.xauth_location) {
732: /* Try to get Xauthority information for the display. */
1.93 itojun 733: snprintf(line, sizeof line, "%.100s list %.200s 2>" _PATH_DEVNULL,
1.55 markus 734: options.xauth_location, getenv("DISPLAY"));
735: f = popen(line, "r");
736: if (f && fgets(line, sizeof(line), f) &&
737: sscanf(line, "%*s %s %s", proto, data) == 2)
738: got_data = 1;
739: if (f)
740: pclose(f);
741: }
1.50 markus 742: /*
743: * If we didn't get authentication data, just make up some
744: * data. The forwarding code will check the validity of the
745: * response anyway, and substitute this data. The X11
746: * server, however, will ignore this fake data and use
747: * whatever authentication mechanisms it was using otherwise
748: * for the local connection.
749: */
750: if (!got_data) {
751: u_int32_t rand = 0;
752:
753: strlcpy(proto, "MIT-MAGIC-COOKIE-1", proto_len);
754: for (i = 0; i < 16; i++) {
755: if (i % 4 == 0)
756: rand = arc4random();
757: snprintf(data + 2 * i, data_len - 2 * i, "%02x", rand & 0xff);
758: rand >>= 8;
759: }
760: }
761: }
762:
1.70 markus 763: void
764: ssh_init_forwarding(void)
765: {
1.86 markus 766: int success = 0;
1.70 markus 767: int i;
1.86 markus 768:
1.70 markus 769: /* Initiate local TCP/IP port forwardings. */
770: for (i = 0; i < options.num_local_forwards; i++) {
771: debug("Connections to local port %d forwarded to remote address %.200s:%d",
772: options.local_forwards[i].port,
773: options.local_forwards[i].host,
774: options.local_forwards[i].host_port);
1.86 markus 775: success += channel_request_local_forwarding(
1.70 markus 776: options.local_forwards[i].port,
777: options.local_forwards[i].host,
778: options.local_forwards[i].host_port,
779: options.gateway_ports);
780: }
1.86 markus 781: if (i > 0 && success == 0)
782: error("Could not request local forwarding.");
1.70 markus 783:
784: /* Initiate remote TCP/IP port forwardings. */
785: for (i = 0; i < options.num_remote_forwards; i++) {
786: debug("Connections to remote port %d forwarded to local address %.200s:%d",
787: options.remote_forwards[i].port,
788: options.remote_forwards[i].host,
789: options.remote_forwards[i].host_port);
790: channel_request_remote_forwarding(
791: options.remote_forwards[i].port,
792: options.remote_forwards[i].host,
793: options.remote_forwards[i].host_port);
794: }
795: }
796:
797: void
798: check_agent_present(void)
799: {
800: if (options.forward_agent) {
801: /* Clear agent forwarding if we don\'t have an agent. */
802: int authfd = ssh_get_authentication_socket();
803: if (authfd < 0)
804: options.forward_agent = 0;
805: else
806: ssh_close_authentication_socket(authfd);
807: }
808: }
809:
1.45 markus 810: int
811: ssh_session(void)
812: {
813: int type;
814: int plen;
815: int interactive = 0;
816: int have_tty = 0;
817: struct winsize ws;
818: char *cp;
819:
1.31 markus 820: /* Enable compression if requested. */
821: if (options.compression) {
822: debug("Requesting compression at level %d.", options.compression_level);
823:
824: if (options.compression_level < 1 || options.compression_level > 9)
825: fatal("Compression level must be from 1 (fast) to 9 (slow, best).");
826:
827: /* Send the request. */
828: packet_start(SSH_CMSG_REQUEST_COMPRESSION);
829: packet_put_int(options.compression_level);
830: packet_send();
831: packet_write_wait();
832: type = packet_read(&plen);
833: if (type == SSH_SMSG_SUCCESS)
834: packet_start_compression(options.compression_level);
835: else if (type == SSH_SMSG_FAILURE)
836: log("Warning: Remote host refused compression.");
837: else
838: packet_disconnect("Protocol error waiting for compression response.");
839: }
840: /* Allocate a pseudo tty if appropriate. */
841: if (tty_flag) {
842: debug("Requesting pty.");
843:
844: /* Start the packet. */
845: packet_start(SSH_CMSG_REQUEST_PTY);
846:
847: /* Store TERM in the packet. There is no limit on the
848: length of the string. */
849: cp = getenv("TERM");
850: if (!cp)
851: cp = "";
1.124 markus 852: packet_put_cstring(cp);
1.31 markus 853:
854: /* Store window size in the packet. */
855: if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
856: memset(&ws, 0, sizeof(ws));
857: packet_put_int(ws.ws_row);
858: packet_put_int(ws.ws_col);
859: packet_put_int(ws.ws_xpixel);
860: packet_put_int(ws.ws_ypixel);
861:
862: /* Store tty modes in the packet. */
1.115 stevesk 863: tty_make_modes(fileno(stdin), NULL);
1.31 markus 864:
865: /* Send the packet, and wait for it to leave. */
866: packet_send();
867: packet_write_wait();
868:
869: /* Read response from the server. */
870: type = packet_read(&plen);
1.43 markus 871: if (type == SSH_SMSG_SUCCESS) {
1.31 markus 872: interactive = 1;
1.45 markus 873: have_tty = 1;
1.43 markus 874: } else if (type == SSH_SMSG_FAILURE)
1.31 markus 875: log("Warning: Remote host failed or refused to allocate a pseudo tty.");
876: else
877: packet_disconnect("Protocol error waiting for pty request response.");
878: }
879: /* Request X11 forwarding if enabled and DISPLAY is set. */
880: if (options.forward_x11 && getenv("DISPLAY") != NULL) {
1.50 markus 881: char proto[512], data[512];
882: /* Get reasonable local authentication information. */
883: x11_get_proto(proto, sizeof proto, data, sizeof data);
884: /* Request forwarding with authentication spoofing. */
1.31 markus 885: debug("Requesting X11 forwarding with authentication spoofing.");
1.50 markus 886: x11_request_forwarding_with_spoofing(0, proto, data);
1.31 markus 887:
888: /* Read response from the server. */
889: type = packet_read(&plen);
890: if (type == SSH_SMSG_SUCCESS) {
891: interactive = 1;
1.50 markus 892: } else if (type == SSH_SMSG_FAILURE) {
1.31 markus 893: log("Warning: Remote host denied X11 forwarding.");
1.50 markus 894: } else {
1.31 markus 895: packet_disconnect("Protocol error waiting for X11 forwarding");
1.50 markus 896: }
1.31 markus 897: }
898: /* Tell the packet module whether this is an interactive session. */
1.80 markus 899: packet_set_interactive(interactive);
1.31 markus 900:
901: /* Request authentication agent forwarding if appropriate. */
1.70 markus 902: check_agent_present();
903:
1.31 markus 904: if (options.forward_agent) {
905: debug("Requesting authentication agent forwarding.");
906: auth_request_forwarding();
907:
908: /* Read response from the server. */
909: type = packet_read(&plen);
910: packet_integrity_check(plen, 0, type);
911: if (type != SSH_SMSG_SUCCESS)
912: log("Warning: Remote host denied authentication agent forwarding.");
913: }
914:
1.70 markus 915: /* Initiate port forwardings. */
916: ssh_init_forwarding();
1.34 markus 917:
918: /* If requested, let ssh continue in the background. */
1.48 markus 919: if (fork_after_authentication_flag)
1.34 markus 920: if (daemon(1, 1) < 0)
921: fatal("daemon() failed: %.200s", strerror(errno));
1.31 markus 922:
1.33 markus 923: /*
924: * If a command was specified on the command line, execute the
925: * command now. Otherwise request the server to start a shell.
926: */
1.31 markus 927: if (buffer_len(&command) > 0) {
928: int len = buffer_len(&command);
929: if (len > 900)
930: len = 900;
931: debug("Sending command: %.*s", len, buffer_ptr(&command));
932: packet_start(SSH_CMSG_EXEC_CMD);
933: packet_put_string(buffer_ptr(&command), buffer_len(&command));
934: packet_send();
935: packet_write_wait();
936: } else {
937: debug("Requesting shell.");
938: packet_start(SSH_CMSG_EXEC_SHELL);
939: packet_send();
940: packet_write_wait();
941: }
942:
943: /* Enter the interactive session. */
1.119 stevesk 944: return client_loop(have_tty, tty_flag ?
945: options.escape_char : SSH_ESCAPECHAR_NONE, 0);
1.45 markus 946: }
947:
948: void
1.89 markus 949: client_subsystem_reply(int type, int plen, void *ctxt)
950: {
951: int id, len;
952:
953: id = packet_get_int();
954: len = buffer_len(&command);
1.100 markus 955: if (len > 900)
956: len = 900;
1.89 markus 957: packet_done();
958: if (type == SSH2_MSG_CHANNEL_FAILURE)
959: fatal("Request for subsystem '%.*s' failed on channel %d",
960: len, buffer_ptr(&command), id);
961: }
962:
963: void
1.70 markus 964: ssh_session2_callback(int id, void *arg)
1.45 markus 965: {
966: int len;
1.80 markus 967: int interactive = 0;
1.115 stevesk 968: struct termios tio;
1.80 markus 969:
1.87 deraadt 970: debug("client_init id %d arg %ld", id, (long)arg);
1.31 markus 971:
1.45 markus 972: if (tty_flag) {
973: struct winsize ws;
974: char *cp;
975: cp = getenv("TERM");
976: if (!cp)
977: cp = "";
978: /* Store window size in the packet. */
979: if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
980: memset(&ws, 0, sizeof(ws));
981:
982: channel_request_start(id, "pty-req", 0);
983: packet_put_cstring(cp);
984: packet_put_int(ws.ws_col);
985: packet_put_int(ws.ws_row);
986: packet_put_int(ws.ws_xpixel);
987: packet_put_int(ws.ws_ypixel);
1.115 stevesk 988: tio = get_saved_tio();
989: tty_make_modes(/*ignored*/ 0, &tio);
1.45 markus 990: packet_send();
1.80 markus 991: interactive = 1;
1.45 markus 992: /* XXX wait for reply */
993: }
1.50 markus 994: if (options.forward_x11 &&
995: getenv("DISPLAY") != NULL) {
996: char proto[512], data[512];
997: /* Get reasonable local authentication information. */
998: x11_get_proto(proto, sizeof proto, data, sizeof data);
999: /* Request forwarding with authentication spoofing. */
1000: debug("Requesting X11 forwarding with authentication spoofing.");
1001: x11_request_forwarding_with_spoofing(id, proto, data);
1.80 markus 1002: interactive = 1;
1.50 markus 1003: /* XXX wait for reply */
1004: }
1005:
1.70 markus 1006: check_agent_present();
1007: if (options.forward_agent) {
1008: debug("Requesting authentication agent forwarding.");
1009: channel_request_start(id, "auth-agent-req@openssh.com", 0);
1010: packet_send();
1011: }
1012:
1.45 markus 1013: len = buffer_len(&command);
1014: if (len > 0) {
1015: if (len > 900)
1016: len = 900;
1.85 djm 1017: if (subsystem_flag) {
1018: debug("Sending subsystem: %.*s", len, buffer_ptr(&command));
1.89 markus 1019: channel_request_start(id, "subsystem", /*want reply*/ 1);
1020: /* register callback for reply */
1021: /* XXX we asume that client_loop has already been called */
1022: dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &client_subsystem_reply);
1023: dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &client_subsystem_reply);
1.85 djm 1024: } else {
1025: debug("Sending command: %.*s", len, buffer_ptr(&command));
1026: channel_request_start(id, "exec", 0);
1027: }
1.100 markus 1028: packet_put_string(buffer_ptr(&command), buffer_len(&command));
1.45 markus 1029: packet_send();
1030: } else {
1031: channel_request(id, "shell", 0);
1032: }
1033: /* channel_callback(id, SSH2_MSG_OPEN_CONFIGMATION, client_init, 0); */
1.90 markus 1034:
1.45 markus 1035: /* register different callback, etc. XXX */
1.80 markus 1036: packet_set_interactive(interactive);
1.45 markus 1037: }
1038:
1039: int
1.106 markus 1040: ssh_session2_command(void)
1.45 markus 1041: {
1.118 markus 1042: Channel *c;
1043: int window, packetmax, in, out, err;
1.60 markus 1044:
1.62 markus 1045: if (stdin_null_flag) {
1.93 itojun 1046: in = open(_PATH_DEVNULL, O_RDONLY);
1.62 markus 1047: } else {
1048: in = dup(STDIN_FILENO);
1049: }
1.60 markus 1050: out = dup(STDOUT_FILENO);
1051: err = dup(STDERR_FILENO);
1.45 markus 1052:
1053: if (in < 0 || out < 0 || err < 0)
1.62 markus 1054: fatal("dup() in/out/err failed");
1.45 markus 1055:
1.69 markus 1056: /* enable nonblocking unless tty */
1057: if (!isatty(in))
1058: set_nonblock(in);
1059: if (!isatty(out))
1060: set_nonblock(out);
1061: if (!isatty(err))
1062: set_nonblock(err);
1063:
1.65 markus 1064: window = CHAN_SES_WINDOW_DEFAULT;
1065: packetmax = CHAN_SES_PACKET_DEFAULT;
1066: if (!tty_flag) {
1.45 markus 1067: window *= 2;
1.65 markus 1068: packetmax *=2;
1.45 markus 1069: }
1.118 markus 1070: c = channel_new(
1.45 markus 1071: "session", SSH_CHANNEL_OPENING, in, out, err,
1.65 markus 1072: window, packetmax, CHAN_EXTENDED_WRITE,
1.69 markus 1073: xstrdup("client-session"), /*nonblock*/0);
1.118 markus 1074: if (c == NULL)
1075: fatal("ssh_session2_command: channel_new failed");
1.45 markus 1076:
1.118 markus 1077: debug3("ssh_session2_command: channel_new: %d", c->self);
1.106 markus 1078:
1.122 markus 1079: channel_send_open(c->self);
1.118 markus 1080: channel_register_callback(c->self, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION,
1.70 markus 1081: ssh_session2_callback, (void *)0);
1.106 markus 1082:
1.118 markus 1083: return c->self;
1.106 markus 1084: }
1085:
1086: int
1087: ssh_session2(void)
1088: {
1089: int id;
1090:
1091: /* XXX should be pre-session */
1092: ssh_init_forwarding();
1093:
1094: id = no_shell_flag ? -1 : ssh_session2_command();
1095:
1096: /* If requested, let ssh continue in the background. */
1097: if (fork_after_authentication_flag)
1098: if (daemon(1, 1) < 0)
1099: fatal("daemon() failed: %.200s", strerror(errno));
1.31 markus 1100:
1.119 stevesk 1101: return client_loop(tty_flag, tty_flag ?
1102: options.escape_char : SSH_ESCAPECHAR_NONE, id);
1.72 markus 1103: }
1104:
1.104 markus 1105: void
1106: load_public_identity_files(void)
1107: {
1108: char *filename;
1109: Key *public;
1110: int i;
1111:
1112: for (i = 0; i < options.num_identity_files; i++) {
1113: filename = tilde_expand_filename(options.identity_files[i],
1114: original_real_uid);
1.105 markus 1115: public = key_load_public(filename, NULL);
1.104 markus 1116: debug("identity file %s type %d", filename,
1117: public ? public->type : -1);
1118: xfree(options.identity_files[i]);
1119: options.identity_files[i] = filename;
1120: options.identity_keys[i] = public;
1121: }
1.1 deraadt 1122: }
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