Annotation of src/usr.bin/ssh/ssh.c, Revision 1.81
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"
1.81 ! markus 42: RCSID("$OpenBSD: ssh.c,v 1.80 2001/01/13 18:32:50 markus Exp $");
1.49 markus 43:
44: #include <openssl/evp.h>
45: #include <openssl/dsa.h>
46: #include <openssl/rsa.h>
1.72 markus 47: #include <openssl/err.h>
1.1 deraadt 48:
49: #include "xmalloc.h"
50: #include "ssh.h"
51: #include "packet.h"
52: #include "buffer.h"
53: #include "readconf.h"
54: #include "uidswap.h"
1.45 markus 55:
56: #include "ssh2.h"
57: #include "compat.h"
1.44 markus 58: #include "channels.h"
1.49 markus 59: #include "key.h"
1.58 markus 60: #include "authfd.h"
1.49 markus 61: #include "authfile.h"
1.81 ! markus 62: #include "clientloop.h"
1.49 markus 63:
64: extern char *__progname;
1.1 deraadt 65:
1.37 markus 66: /* Flag indicating whether IPv4 or IPv6. This can be set on the command line.
67: Default value is AF_UNSPEC means both IPv4 and IPv6. */
68: int IPv4or6 = AF_UNSPEC;
69:
1.31 markus 70: /* Flag indicating whether debug mode is on. This can be set on the command line. */
1.1 deraadt 71: int debug_flag = 0;
72:
1.46 markus 73: /* Flag indicating whether a tty should be allocated */
1.1 deraadt 74: int tty_flag = 0;
1.79 markus 75: int no_tty_flag = 0;
76: int force_tty_flag = 0;
1.1 deraadt 77:
1.45 markus 78: /* don't exec a shell */
79: int no_shell_flag = 0;
80:
1.33 markus 81: /*
82: * Flag indicating that nothing should be read from stdin. This can be set
83: * on the command line.
84: */
1.1 deraadt 85: int stdin_null_flag = 0;
86:
1.33 markus 87: /*
88: * Flag indicating that ssh should fork after authentication. This is useful
89: * so that the pasphrase can be entered manually, and then ssh goes to the
90: * background.
91: */
1.1 deraadt 92: int fork_after_authentication_flag = 0;
93:
1.33 markus 94: /*
95: * General data structure for command line options and options configurable
96: * in configuration files. See readconf.h.
97: */
1.1 deraadt 98: Options options;
99:
1.33 markus 100: /*
101: * Name of the host we are connecting to. This is the name given on the
102: * command line, or the HostName specified for the user-supplied name in a
103: * configuration file.
104: */
1.1 deraadt 105: char *host;
106:
1.22 provos 107: /* socket address the host resolves to */
1.37 markus 108: struct sockaddr_storage hostaddr;
1.22 provos 109:
1.33 markus 110: /*
111: * Flag to indicate that we have received a window change signal which has
112: * not yet been processed. This will cause a message indicating the new
113: * window size to be sent to the server a little later. This is volatile
114: * because this is updated in a signal handler.
115: */
1.1 deraadt 116: volatile int received_window_change_signal = 0;
117:
118: /* Flag indicating whether we have a valid host private key loaded. */
119: int host_private_key_loaded = 0;
120:
121: /* Host private key. */
1.2 provos 122: RSA *host_private_key = NULL;
1.1 deraadt 123:
1.10 dugsong 124: /* Original real UID. */
125: uid_t original_real_uid;
1.1 deraadt 126:
1.45 markus 127: /* command to be executed */
128: Buffer command;
129:
1.1 deraadt 130: /* Prints a help message to the user. This function never returns. */
131:
1.2 provos 132: void
133: usage()
1.1 deraadt 134: {
1.76 markus 135: fprintf(stderr, "Usage: %s [options] host [command]\n", __progname);
1.31 markus 136: fprintf(stderr, "Options:\n");
137: fprintf(stderr, " -l user Log in using this user name.\n");
138: fprintf(stderr, " -n Redirect input from /dev/null.\n");
1.53 markus 139: fprintf(stderr, " -A Enable authentication agent forwarding.\n");
1.31 markus 140: fprintf(stderr, " -a Disable authentication agent forwarding.\n");
1.9 dugsong 141: #ifdef AFS
1.31 markus 142: fprintf(stderr, " -k Disable Kerberos ticket and AFS token forwarding.\n");
143: #endif /* AFS */
1.52 markus 144: fprintf(stderr, " -X Enable X11 connection forwarding.\n");
1.31 markus 145: fprintf(stderr, " -x Disable X11 connection forwarding.\n");
146: fprintf(stderr, " -i file Identity for RSA authentication (default: ~/.ssh/identity).\n");
147: fprintf(stderr, " -t Tty; allocate a tty even if command is given.\n");
1.45 markus 148: fprintf(stderr, " -T Do not allocate a tty.\n");
1.31 markus 149: fprintf(stderr, " -v Verbose; display verbose debugging messages.\n");
1.66 markus 150: fprintf(stderr, " Multiple -v increases verbosity.\n");
1.31 markus 151: fprintf(stderr, " -V Display version number only.\n");
152: fprintf(stderr, " -P Don't allocate a privileged port.\n");
153: fprintf(stderr, " -q Quiet; don't display any warning messages.\n");
154: fprintf(stderr, " -f Fork into background after authentication.\n");
155: fprintf(stderr, " -e char Set escape character; ``none'' = disable (default: ~).\n");
156:
157: fprintf(stderr, " -c cipher Select encryption algorithm: "
158: "``3des'', "
159: "``blowfish''\n");
160: fprintf(stderr, " -p port Connect to this port. Server must be on the same port.\n");
161: fprintf(stderr, " -L listen-port:host:port Forward local port to remote address\n");
162: fprintf(stderr, " -R listen-port:host:port Forward remote port to local address\n");
1.76 markus 163: fprintf(stderr, " These cause %s to listen for connections on a port, and\n", __progname);
1.31 markus 164: fprintf(stderr, " forward them to the other side by connecting to host:port.\n");
165: fprintf(stderr, " -C Enable compression.\n");
1.45 markus 166: fprintf(stderr, " -N Do not execute a shell or command.\n");
1.31 markus 167: fprintf(stderr, " -g Allow remote hosts to connect to forwarded ports.\n");
1.37 markus 168: fprintf(stderr, " -4 Use IPv4 only.\n");
169: fprintf(stderr, " -6 Use IPv6 only.\n");
1.47 markus 170: fprintf(stderr, " -2 Force protocol version 2.\n");
1.31 markus 171: fprintf(stderr, " -o 'option' Process the option as if it was read from a configuration file.\n");
172: exit(1);
1.1 deraadt 173: }
174:
1.32 deraadt 175: /*
176: * Connects to the given host using rsh (or prints an error message and exits
177: * if rsh is not available). This function never returns.
178: */
1.2 provos 179: void
1.31 markus 180: rsh_connect(char *host, char *user, Buffer * command)
1.1 deraadt 181: {
1.31 markus 182: char *args[10];
183: int i;
184:
185: log("Using rsh. WARNING: Connection will not be encrypted.");
186: /* Build argument list for rsh. */
187: i = 0;
188: args[i++] = _PATH_RSH;
189: /* host may have to come after user on some systems */
190: args[i++] = host;
191: if (user) {
192: args[i++] = "-l";
193: args[i++] = user;
194: }
195: if (buffer_len(command) > 0) {
196: buffer_append(command, "\0", 1);
197: args[i++] = buffer_ptr(command);
198: }
199: args[i++] = NULL;
200: if (debug_flag) {
201: for (i = 0; args[i]; i++) {
202: if (i != 0)
203: fprintf(stderr, " ");
204: fprintf(stderr, "%s", args[i]);
205: }
206: fprintf(stderr, "\n");
207: }
208: execv(_PATH_RSH, args);
209: perror(_PATH_RSH);
210: exit(1);
1.1 deraadt 211: }
212:
1.72 markus 213: int ssh_session(void);
214: int ssh_session2(void);
215: int guess_identity_file_type(const char *filename);
1.45 markus 216:
1.32 deraadt 217: /*
218: * Main program for the ssh client.
219: */
1.2 provos 220: int
221: main(int ac, char **av)
1.1 deraadt 222: {
1.45 markus 223: int i, opt, optind, exit_status, ok;
1.35 markus 224: u_short fwd_port, fwd_host_port;
1.31 markus 225: char *optarg, *cp, buf[256];
226: struct stat st;
227: struct passwd *pw, pwcopy;
1.45 markus 228: int dummy;
1.31 markus 229: uid_t original_effective_uid;
230:
1.33 markus 231: /*
232: * Save the original real uid. It will be needed later (uid-swapping
233: * may clobber the real uid).
234: */
1.31 markus 235: original_real_uid = getuid();
236: original_effective_uid = geteuid();
237:
238: /* If we are installed setuid root be careful to not drop core. */
239: if (original_real_uid != original_effective_uid) {
240: struct rlimit rlim;
241: rlim.rlim_cur = rlim.rlim_max = 0;
242: if (setrlimit(RLIMIT_CORE, &rlim) < 0)
243: fatal("setrlimit failed: %.100s", strerror(errno));
1.1 deraadt 244: }
1.33 markus 245: /*
246: * Use uid-swapping to give up root privileges for the duration of
247: * option processing. We will re-instantiate the rights when we are
248: * ready to create the privileged port, and will permanently drop
249: * them when the port has been created (actually, when the connection
250: * has been made, as we may need to create the port several times).
251: */
1.31 markus 252: temporarily_use_uid(original_real_uid);
253:
1.33 markus 254: /*
255: * Set our umask to something reasonable, as some files are created
256: * with the default umask. This will make them world-readable but
257: * writable only by the owner, which is ok for all files for which we
258: * don't set the modes explicitly.
259: */
1.31 markus 260: umask(022);
261:
262: /* Initialize option structure to indicate that no values have been set. */
263: initialize_options(&options);
264:
265: /* Parse command-line arguments. */
266: host = NULL;
267:
268: /* If program name is not one of the standard names, use it as host name. */
1.76 markus 269: cp = __progname;
1.59 deraadt 270: if (strcmp(cp, "rsh") && strcmp(cp, "ssh") && strcmp(cp, "rlogin") &&
271: strcmp(cp, "slogin") && strcmp(cp, "remsh"))
1.31 markus 272: host = cp;
273:
274: for (optind = 1; optind < ac; optind++) {
275: if (av[optind][0] != '-') {
276: if (host)
277: break;
278: if ((cp = strchr(av[optind], '@'))) {
1.48 markus 279: if(cp == av[optind])
280: usage();
1.31 markus 281: options.user = av[optind];
282: *cp = '\0';
283: host = ++cp;
284: } else
285: host = av[optind];
286: continue;
287: }
288: opt = av[optind][1];
289: if (!opt)
290: usage();
291: if (strchr("eilcpLRo", opt)) { /* options with arguments */
292: optarg = av[optind] + 2;
293: if (strcmp(optarg, "") == 0) {
294: if (optind >= ac - 1)
295: usage();
296: optarg = av[++optind];
297: }
298: } else {
299: if (av[optind][2])
300: usage();
301: optarg = NULL;
302: }
303: switch (opt) {
1.47 markus 304: case '2':
305: options.protocol = SSH_PROTO_2;
306: break;
1.37 markus 307: case '4':
308: IPv4or6 = AF_INET;
309: break;
310: case '6':
311: IPv4or6 = AF_INET6;
312: break;
1.31 markus 313: case 'n':
314: stdin_null_flag = 1;
315: break;
316: case 'f':
317: fork_after_authentication_flag = 1;
318: stdin_null_flag = 1;
319: break;
320: case 'x':
321: options.forward_x11 = 0;
322: break;
323: case 'X':
324: options.forward_x11 = 1;
325: break;
326: case 'g':
327: options.gateway_ports = 1;
328: break;
329: case 'P':
330: options.use_privileged_port = 0;
331: break;
332: case 'a':
333: options.forward_agent = 0;
1.53 markus 334: break;
335: case 'A':
336: options.forward_agent = 1;
1.31 markus 337: break;
1.9 dugsong 338: #ifdef AFS
1.31 markus 339: case 'k':
340: options.kerberos_tgt_passing = 0;
341: options.afs_token_passing = 0;
342: break;
1.1 deraadt 343: #endif
1.31 markus 344: case 'i':
345: if (stat(optarg, &st) < 0) {
346: fprintf(stderr, "Warning: Identity file %s does not exist.\n",
1.72 markus 347: optarg);
1.31 markus 348: break;
349: }
350: if (options.num_identity_files >= SSH_MAX_IDENTITY_FILES)
351: fatal("Too many identity files specified (max %d)",
1.72 markus 352: SSH_MAX_IDENTITY_FILES);
353: options.identity_files[options.num_identity_files++] = xstrdup(optarg);
1.31 markus 354: break;
355: case 't':
1.79 markus 356: if (tty_flag)
357: force_tty_flag = 1;
1.31 markus 358: tty_flag = 1;
359: break;
360: case 'v':
1.66 markus 361: if (0 == debug_flag) {
362: debug_flag = 1;
363: options.log_level = SYSLOG_LEVEL_DEBUG1;
364: } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) {
365: options.log_level++;
366: break;
367: } else {
368: fatal("Too high debugging level.\n");
369: }
370: /* fallthrough */
1.31 markus 371: case 'V':
1.46 markus 372: fprintf(stderr, "SSH Version %s, protocol versions %d.%d/%d.%d.\n",
373: SSH_VERSION,
374: PROTOCOL_MAJOR_1, PROTOCOL_MINOR_1,
375: PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2);
1.45 markus 376: fprintf(stderr, "Compiled with SSL (0x%8.8lx).\n", SSLeay());
1.31 markus 377: if (opt == 'V')
378: exit(0);
379: break;
380: case 'q':
381: options.log_level = SYSLOG_LEVEL_QUIET;
382: break;
383: case 'e':
384: if (optarg[0] == '^' && optarg[2] == 0 &&
1.78 markus 385: (u_char) optarg[1] >= 64 && (u_char) optarg[1] < 128)
386: options.escape_char = (u_char) optarg[1] & 31;
1.31 markus 387: else if (strlen(optarg) == 1)
1.78 markus 388: options.escape_char = (u_char) optarg[0];
1.31 markus 389: else if (strcmp(optarg, "none") == 0)
390: options.escape_char = -2;
391: else {
392: fprintf(stderr, "Bad escape character '%s'.\n", optarg);
393: exit(1);
394: }
395: break;
396: case 'c':
1.49 markus 397: if (ciphers_valid(optarg)) {
398: /* SSH2 only */
399: options.ciphers = xstrdup(optarg);
1.51 markus 400: options.cipher = SSH_CIPHER_ILLEGAL;
1.49 markus 401: } else {
402: /* SSH1 only */
1.74 markus 403: options.cipher = cipher_number(optarg);
404: if (options.cipher == -1) {
1.49 markus 405: fprintf(stderr, "Unknown cipher type '%s'\n", optarg);
406: exit(1);
407: }
1.74 markus 408: if (options.cipher == SSH_CIPHER_3DES) {
409: options.ciphers = "3des-cbc";
410: } else if (options.cipher == SSH_CIPHER_BLOWFISH) {
411: options.ciphers = "blowfish-cbc";
412: } else {
413: options.ciphers = (char *)-1;
414: }
1.31 markus 415: }
416: break;
417: case 'p':
418: options.port = atoi(optarg);
419: break;
420: case 'l':
421: options.user = optarg;
422: break;
423: case 'R':
1.37 markus 424: if (sscanf(optarg, "%hu/%255[^/]/%hu", &fwd_port, buf,
425: &fwd_host_port) != 3 &&
426: sscanf(optarg, "%hu:%255[^:]:%hu", &fwd_port, buf,
427: &fwd_host_port) != 3) {
1.31 markus 428: fprintf(stderr, "Bad forwarding specification '%s'.\n", optarg);
429: usage();
430: /* NOTREACHED */
431: }
432: add_remote_forward(&options, fwd_port, buf, fwd_host_port);
433: break;
434: case 'L':
1.37 markus 435: if (sscanf(optarg, "%hu/%255[^/]/%hu", &fwd_port, buf,
436: &fwd_host_port) != 3 &&
437: sscanf(optarg, "%hu:%255[^:]:%hu", &fwd_port, buf,
438: &fwd_host_port) != 3) {
1.31 markus 439: fprintf(stderr, "Bad forwarding specification '%s'.\n", optarg);
440: usage();
441: /* NOTREACHED */
442: }
443: add_local_forward(&options, fwd_port, buf, fwd_host_port);
444: break;
445: case 'C':
446: options.compression = 1;
447: break;
1.45 markus 448: case 'N':
449: no_shell_flag = 1;
450: no_tty_flag = 1;
451: break;
452: case 'T':
453: no_tty_flag = 1;
454: break;
1.31 markus 455: case 'o':
456: dummy = 1;
457: if (process_config_line(&options, host ? host : "", optarg,
458: "command-line", 0, &dummy) != 0)
459: exit(1);
460: break;
461: default:
462: usage();
1.1 deraadt 463: }
1.31 markus 464: }
465:
466: /* Check that we got a host name. */
467: if (!host)
468: usage();
469:
1.54 markus 470: SSLeay_add_all_algorithms();
1.72 markus 471: ERR_load_crypto_strings();
1.31 markus 472:
473: /* Initialize the command to execute on remote host. */
474: buffer_init(&command);
1.1 deraadt 475:
1.33 markus 476: /*
477: * Save the command to execute on the remote host in a buffer. There
478: * is no limit on the length of the command, except by the maximum
479: * packet size. Also sets the tty flag if there is no command.
480: */
1.31 markus 481: if (optind == ac) {
482: /* No command specified - execute shell on a tty. */
483: tty_flag = 1;
484: } else {
485: /* A command has been specified. Store it into the
486: buffer. */
487: for (i = optind; i < ac; i++) {
488: if (i > optind)
489: buffer_append(&command, " ", 1);
490: buffer_append(&command, av[i], strlen(av[i]));
491: }
492: }
493:
494: /* Cannot fork to background if no command. */
1.63 markus 495: if (fork_after_authentication_flag && buffer_len(&command) == 0 && !no_shell_flag)
1.31 markus 496: fatal("Cannot fork into background without a command to execute.");
497:
498: /* Allocate a tty by default if no command specified. */
499: if (buffer_len(&command) == 0)
500: tty_flag = 1;
501:
1.75 markus 502: /* Force no tty*/
503: if (no_tty_flag)
504: tty_flag = 0;
1.31 markus 505: /* Do not allocate a tty if stdin is not a tty. */
1.79 markus 506: if (!isatty(fileno(stdin)) && !force_tty_flag) {
1.31 markus 507: if (tty_flag)
508: fprintf(stderr, "Pseudo-terminal will not be allocated because stdin is not a terminal.\n");
509: tty_flag = 0;
510: }
1.45 markus 511:
1.31 markus 512: /* Get user data. */
513: pw = getpwuid(original_real_uid);
514: if (!pw) {
515: fprintf(stderr, "You don't exist, go away!\n");
516: exit(1);
517: }
518: /* Take a copy of the returned structure. */
519: memset(&pwcopy, 0, sizeof(pwcopy));
520: pwcopy.pw_name = xstrdup(pw->pw_name);
521: pwcopy.pw_passwd = xstrdup(pw->pw_passwd);
522: pwcopy.pw_uid = pw->pw_uid;
523: pwcopy.pw_gid = pw->pw_gid;
1.61 millert 524: pwcopy.pw_class = xstrdup(pw->pw_class);
1.31 markus 525: pwcopy.pw_dir = xstrdup(pw->pw_dir);
526: pwcopy.pw_shell = xstrdup(pw->pw_shell);
527: pw = &pwcopy;
528:
529: /* Initialize "log" output. Since we are the client all output
530: actually goes to the terminal. */
531: log_init(av[0], options.log_level, SYSLOG_FACILITY_USER, 0);
532:
533: /* Read per-user configuration file. */
534: snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir, SSH_USER_CONFFILE);
535: read_config_file(buf, host, &options);
536:
537: /* Read systemwide configuration file. */
538: read_config_file(HOST_CONFIG_FILE, host, &options);
539:
540: /* Fill configuration defaults. */
541: fill_default_options(&options);
542:
543: /* reinit */
544: log_init(av[0], options.log_level, SYSLOG_FACILITY_USER, 0);
545:
546: if (options.user == NULL)
547: options.user = xstrdup(pw->pw_name);
548:
549: if (options.hostname != NULL)
550: host = options.hostname;
551:
552: /* Disable rhosts authentication if not running as root. */
553: if (original_effective_uid != 0 || !options.use_privileged_port) {
1.77 markus 554: debug("Rhosts Authentication disabled, "
1.71 markus 555: "originating port will not be trusted.");
1.31 markus 556: options.rhosts_authentication = 0;
557: }
1.33 markus 558: /*
559: * If using rsh has been selected, exec it now (without trying
560: * anything else). Note that we must release privileges first.
561: */
1.31 markus 562: if (options.use_rsh) {
1.33 markus 563: /*
564: * Restore our superuser privileges. This must be done
565: * before permanently setting the uid.
566: */
1.31 markus 567: restore_uid();
568:
569: /* Switch to the original uid permanently. */
570: permanently_set_uid(original_real_uid);
571:
572: /* Execute rsh. */
573: rsh_connect(host, options.user, &command);
574: fatal("rsh_connect returned");
575: }
576: /* Restore our superuser privileges. */
577: restore_uid();
578:
1.77 markus 579: /* Open a connection to the remote host. */
1.31 markus 580:
581: ok = ssh_connect(host, &hostaddr, options.port,
1.77 markus 582: options.connection_attempts,
583: original_effective_uid != 0 || !options.use_privileged_port,
584: original_real_uid,
585: options.proxy_command);
1.31 markus 586:
1.33 markus 587: /*
588: * If we successfully made the connection, load the host private key
589: * in case we will need it later for combined rsa-rhosts
590: * authentication. This must be done before releasing extra
591: * privileges, because the file is only readable by root.
592: */
1.49 markus 593: if (ok && (options.protocol & SSH_PROTO_1)) {
594: Key k;
1.31 markus 595: host_private_key = RSA_new();
1.72 markus 596: k.type = KEY_RSA1;
1.49 markus 597: k.rsa = host_private_key;
598: if (load_private_key(HOST_KEY_FILE, "", &k, NULL))
1.31 markus 599: host_private_key_loaded = 1;
600: }
1.33 markus 601: /*
602: * Get rid of any extra privileges that we may have. We will no
603: * longer need them. Also, extra privileges could make it very hard
604: * to read identity files and other non-world-readable files from the
605: * user's home directory if it happens to be on a NFS volume where
606: * root is mapped to nobody.
607: */
608:
609: /*
610: * Note that some legacy systems need to postpone the following call
611: * to permanently_set_uid() until the private hostkey is destroyed
612: * with RSA_free(). Otherwise the calling user could ptrace() the
613: * process, read the private hostkey and impersonate the host.
614: * OpenBSD does not allow ptracing of setuid processes.
615: */
1.31 markus 616: permanently_set_uid(original_real_uid);
617:
1.33 markus 618: /*
619: * Now that we are back to our own permissions, create ~/.ssh
620: * directory if it doesn\'t already exist.
621: */
1.31 markus 622: snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir, SSH_USER_DIR);
623: if (stat(buf, &st) < 0)
1.57 djm 624: if (mkdir(buf, 0700) < 0)
1.31 markus 625: error("Could not create directory '%.200s'.", buf);
626:
627: /* Check if the connection failed, and try "rsh" if appropriate. */
628: if (!ok) {
629: if (options.port != 0)
1.35 markus 630: log("Secure connection to %.100s on port %hu refused%.100s.",
1.31 markus 631: host, options.port,
632: options.fallback_to_rsh ? "; reverting to insecure method" : "");
633: else
634: log("Secure connection to %.100s refused%.100s.", host,
635: options.fallback_to_rsh ? "; reverting to insecure method" : "");
636:
637: if (options.fallback_to_rsh) {
638: rsh_connect(host, options.user, &command);
639: fatal("rsh_connect returned");
640: }
641: exit(1);
642: }
1.72 markus 643: /* Expand ~ in options.identity_files, known host file names. */
1.49 markus 644: /* XXX mem-leaks */
1.72 markus 645: for (i = 0; i < options.num_identity_files; i++) {
1.31 markus 646: options.identity_files[i] =
1.72 markus 647: tilde_expand_filename(options.identity_files[i], original_real_uid);
648: options.identity_files_type[i] = guess_identity_file_type(options.identity_files[i]);
649: debug("identity file %s type %d", options.identity_files[i],
650: options.identity_files_type[i]);
651: }
652: options.system_hostfile =
653: tilde_expand_filename(options.system_hostfile, original_real_uid);
654: options.user_hostfile =
655: tilde_expand_filename(options.user_hostfile, original_real_uid);
656: options.system_hostfile2 =
657: tilde_expand_filename(options.system_hostfile2, original_real_uid);
658: options.user_hostfile2 =
659: tilde_expand_filename(options.user_hostfile2, original_real_uid);
1.31 markus 660:
661: /* Log into the remote system. This never returns if the login fails. */
662: ssh_login(host_private_key_loaded, host_private_key,
1.37 markus 663: host, (struct sockaddr *)&hostaddr, original_real_uid);
1.31 markus 664:
665: /* We no longer need the host private key. Clear it now. */
666: if (host_private_key_loaded)
667: RSA_free(host_private_key); /* Destroys contents safely */
668:
1.45 markus 669: exit_status = compat20 ? ssh_session2() : ssh_session();
670: packet_close();
671: return exit_status;
672: }
673:
1.50 markus 674: void
675: x11_get_proto(char *proto, int proto_len, char *data, int data_len)
676: {
677: char line[512];
678: FILE *f;
679: int got_data = 0, i;
680:
1.55 markus 681: if (options.xauth_location) {
682: /* Try to get Xauthority information for the display. */
683: snprintf(line, sizeof line, "%.100s list %.200s 2>/dev/null",
684: options.xauth_location, getenv("DISPLAY"));
685: f = popen(line, "r");
686: if (f && fgets(line, sizeof(line), f) &&
687: sscanf(line, "%*s %s %s", proto, data) == 2)
688: got_data = 1;
689: if (f)
690: pclose(f);
691: }
1.50 markus 692: /*
693: * If we didn't get authentication data, just make up some
694: * data. The forwarding code will check the validity of the
695: * response anyway, and substitute this data. The X11
696: * server, however, will ignore this fake data and use
697: * whatever authentication mechanisms it was using otherwise
698: * for the local connection.
699: */
700: if (!got_data) {
701: u_int32_t rand = 0;
702:
703: strlcpy(proto, "MIT-MAGIC-COOKIE-1", proto_len);
704: for (i = 0; i < 16; i++) {
705: if (i % 4 == 0)
706: rand = arc4random();
707: snprintf(data + 2 * i, data_len - 2 * i, "%02x", rand & 0xff);
708: rand >>= 8;
709: }
710: }
711: }
712:
1.70 markus 713: void
714: ssh_init_forwarding(void)
715: {
716: int i;
717: /* Initiate local TCP/IP port forwardings. */
718: for (i = 0; i < options.num_local_forwards; i++) {
719: debug("Connections to local port %d forwarded to remote address %.200s:%d",
720: options.local_forwards[i].port,
721: options.local_forwards[i].host,
722: options.local_forwards[i].host_port);
723: channel_request_local_forwarding(
724: options.local_forwards[i].port,
725: options.local_forwards[i].host,
726: options.local_forwards[i].host_port,
727: options.gateway_ports);
728: }
729:
730: /* Initiate remote TCP/IP port forwardings. */
731: for (i = 0; i < options.num_remote_forwards; i++) {
732: debug("Connections to remote port %d forwarded to local address %.200s:%d",
733: options.remote_forwards[i].port,
734: options.remote_forwards[i].host,
735: options.remote_forwards[i].host_port);
736: channel_request_remote_forwarding(
737: options.remote_forwards[i].port,
738: options.remote_forwards[i].host,
739: options.remote_forwards[i].host_port);
740: }
741: }
742:
743: void
744: check_agent_present(void)
745: {
746: if (options.forward_agent) {
747: /* Clear agent forwarding if we don\'t have an agent. */
748: int authfd = ssh_get_authentication_socket();
749: if (authfd < 0)
750: options.forward_agent = 0;
751: else
752: ssh_close_authentication_socket(authfd);
753: }
754: }
755:
1.45 markus 756: int
757: ssh_session(void)
758: {
759: int type;
760: int plen;
761: int interactive = 0;
762: int have_tty = 0;
763: struct winsize ws;
764: char *cp;
765:
1.31 markus 766: /* Enable compression if requested. */
767: if (options.compression) {
768: debug("Requesting compression at level %d.", options.compression_level);
769:
770: if (options.compression_level < 1 || options.compression_level > 9)
771: fatal("Compression level must be from 1 (fast) to 9 (slow, best).");
772:
773: /* Send the request. */
774: packet_start(SSH_CMSG_REQUEST_COMPRESSION);
775: packet_put_int(options.compression_level);
776: packet_send();
777: packet_write_wait();
778: type = packet_read(&plen);
779: if (type == SSH_SMSG_SUCCESS)
780: packet_start_compression(options.compression_level);
781: else if (type == SSH_SMSG_FAILURE)
782: log("Warning: Remote host refused compression.");
783: else
784: packet_disconnect("Protocol error waiting for compression response.");
785: }
786: /* Allocate a pseudo tty if appropriate. */
787: if (tty_flag) {
788: debug("Requesting pty.");
789:
790: /* Start the packet. */
791: packet_start(SSH_CMSG_REQUEST_PTY);
792:
793: /* Store TERM in the packet. There is no limit on the
794: length of the string. */
795: cp = getenv("TERM");
796: if (!cp)
797: cp = "";
798: packet_put_string(cp, strlen(cp));
799:
800: /* Store window size in the packet. */
801: if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
802: memset(&ws, 0, sizeof(ws));
803: packet_put_int(ws.ws_row);
804: packet_put_int(ws.ws_col);
805: packet_put_int(ws.ws_xpixel);
806: packet_put_int(ws.ws_ypixel);
807:
808: /* Store tty modes in the packet. */
809: tty_make_modes(fileno(stdin));
810:
811: /* Send the packet, and wait for it to leave. */
812: packet_send();
813: packet_write_wait();
814:
815: /* Read response from the server. */
816: type = packet_read(&plen);
1.43 markus 817: if (type == SSH_SMSG_SUCCESS) {
1.31 markus 818: interactive = 1;
1.45 markus 819: have_tty = 1;
1.43 markus 820: } else if (type == SSH_SMSG_FAILURE)
1.31 markus 821: log("Warning: Remote host failed or refused to allocate a pseudo tty.");
822: else
823: packet_disconnect("Protocol error waiting for pty request response.");
824: }
825: /* Request X11 forwarding if enabled and DISPLAY is set. */
826: if (options.forward_x11 && getenv("DISPLAY") != NULL) {
1.50 markus 827: char proto[512], data[512];
828: /* Get reasonable local authentication information. */
829: x11_get_proto(proto, sizeof proto, data, sizeof data);
830: /* Request forwarding with authentication spoofing. */
1.31 markus 831: debug("Requesting X11 forwarding with authentication spoofing.");
1.50 markus 832: x11_request_forwarding_with_spoofing(0, proto, data);
1.31 markus 833:
834: /* Read response from the server. */
835: type = packet_read(&plen);
836: if (type == SSH_SMSG_SUCCESS) {
837: interactive = 1;
1.50 markus 838: } else if (type == SSH_SMSG_FAILURE) {
1.31 markus 839: log("Warning: Remote host denied X11 forwarding.");
1.50 markus 840: } else {
1.31 markus 841: packet_disconnect("Protocol error waiting for X11 forwarding");
1.50 markus 842: }
1.31 markus 843: }
844: /* Tell the packet module whether this is an interactive session. */
1.80 markus 845: packet_set_interactive(interactive);
1.31 markus 846:
847: /* Request authentication agent forwarding if appropriate. */
1.70 markus 848: check_agent_present();
849:
1.31 markus 850: if (options.forward_agent) {
851: debug("Requesting authentication agent forwarding.");
852: auth_request_forwarding();
853:
854: /* Read response from the server. */
855: type = packet_read(&plen);
856: packet_integrity_check(plen, 0, type);
857: if (type != SSH_SMSG_SUCCESS)
858: log("Warning: Remote host denied authentication agent forwarding.");
859: }
860:
1.70 markus 861: /* Initiate port forwardings. */
862: ssh_init_forwarding();
1.34 markus 863:
864: /* If requested, let ssh continue in the background. */
1.48 markus 865: if (fork_after_authentication_flag)
1.34 markus 866: if (daemon(1, 1) < 0)
867: fatal("daemon() failed: %.200s", strerror(errno));
1.31 markus 868:
1.33 markus 869: /*
870: * If a command was specified on the command line, execute the
871: * command now. Otherwise request the server to start a shell.
872: */
1.31 markus 873: if (buffer_len(&command) > 0) {
874: int len = buffer_len(&command);
875: if (len > 900)
876: len = 900;
877: debug("Sending command: %.*s", len, buffer_ptr(&command));
878: packet_start(SSH_CMSG_EXEC_CMD);
879: packet_put_string(buffer_ptr(&command), buffer_len(&command));
880: packet_send();
881: packet_write_wait();
882: } else {
883: debug("Requesting shell.");
884: packet_start(SSH_CMSG_EXEC_SHELL);
885: packet_send();
886: packet_write_wait();
887: }
888:
889: /* Enter the interactive session. */
1.60 markus 890: return client_loop(have_tty, tty_flag ? options.escape_char : -1, 0);
1.45 markus 891: }
892:
893: void
1.70 markus 894: ssh_session2_callback(int id, void *arg)
1.45 markus 895: {
896: int len;
1.80 markus 897: int interactive = 0;
898:
1.45 markus 899: debug("client_init id %d arg %d", id, (int)arg);
1.31 markus 900:
1.45 markus 901: if (no_shell_flag)
902: goto done;
903:
904: if (tty_flag) {
905: struct winsize ws;
906: char *cp;
907: cp = getenv("TERM");
908: if (!cp)
909: cp = "";
910: /* Store window size in the packet. */
911: if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
912: memset(&ws, 0, sizeof(ws));
913:
914: channel_request_start(id, "pty-req", 0);
915: packet_put_cstring(cp);
916: packet_put_int(ws.ws_col);
917: packet_put_int(ws.ws_row);
918: packet_put_int(ws.ws_xpixel);
919: packet_put_int(ws.ws_ypixel);
920: packet_put_cstring(""); /* XXX: encode terminal modes */
921: packet_send();
1.80 markus 922: interactive = 1;
1.45 markus 923: /* XXX wait for reply */
924: }
1.50 markus 925: if (options.forward_x11 &&
926: getenv("DISPLAY") != NULL) {
927: char proto[512], data[512];
928: /* Get reasonable local authentication information. */
929: x11_get_proto(proto, sizeof proto, data, sizeof data);
930: /* Request forwarding with authentication spoofing. */
931: debug("Requesting X11 forwarding with authentication spoofing.");
932: x11_request_forwarding_with_spoofing(id, proto, data);
1.80 markus 933: interactive = 1;
1.50 markus 934: /* XXX wait for reply */
935: }
936:
1.70 markus 937: check_agent_present();
938: if (options.forward_agent) {
939: debug("Requesting authentication agent forwarding.");
940: channel_request_start(id, "auth-agent-req@openssh.com", 0);
941: packet_send();
942: }
943:
1.45 markus 944: len = buffer_len(&command);
945: if (len > 0) {
946: if (len > 900)
947: len = 900;
948: debug("Sending command: %.*s", len, buffer_ptr(&command));
949: channel_request_start(id, "exec", 0);
950: packet_put_string(buffer_ptr(&command), len);
951: packet_send();
952: } else {
953: channel_request(id, "shell", 0);
954: }
955: /* channel_callback(id, SSH2_MSG_OPEN_CONFIGMATION, client_init, 0); */
956: done:
957: /* register different callback, etc. XXX */
1.80 markus 958: packet_set_interactive(interactive);
1.81 ! markus 959: clientloop_set_session_ident(id);
1.45 markus 960: }
961:
962: int
963: ssh_session2(void)
964: {
965: int window, packetmax, id;
1.60 markus 966: int in, out, err;
967:
1.62 markus 968: if (stdin_null_flag) {
969: in = open("/dev/null", O_RDONLY);
970: } else {
971: in = dup(STDIN_FILENO);
972: }
1.60 markus 973: out = dup(STDOUT_FILENO);
974: err = dup(STDERR_FILENO);
1.45 markus 975:
976: if (in < 0 || out < 0 || err < 0)
1.62 markus 977: fatal("dup() in/out/err failed");
1.45 markus 978:
1.69 markus 979: /* enable nonblocking unless tty */
980: if (!isatty(in))
981: set_nonblock(in);
982: if (!isatty(out))
983: set_nonblock(out);
984: if (!isatty(err))
985: set_nonblock(err);
986:
1.70 markus 987: /* XXX should be pre-session */
988: ssh_init_forwarding();
1.45 markus 989:
1.62 markus 990: /* If requested, let ssh continue in the background. */
991: if (fork_after_authentication_flag)
992: if (daemon(1, 1) < 0)
993: fatal("daemon() failed: %.200s", strerror(errno));
994:
1.65 markus 995: window = CHAN_SES_WINDOW_DEFAULT;
996: packetmax = CHAN_SES_PACKET_DEFAULT;
997: if (!tty_flag) {
1.45 markus 998: window *= 2;
1.65 markus 999: packetmax *=2;
1.45 markus 1000: }
1001: id = channel_new(
1002: "session", SSH_CHANNEL_OPENING, in, out, err,
1.65 markus 1003: window, packetmax, CHAN_EXTENDED_WRITE,
1.69 markus 1004: xstrdup("client-session"), /*nonblock*/0);
1.45 markus 1005:
1006: channel_open(id);
1.70 markus 1007: channel_register_callback(id, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION,
1008: ssh_session2_callback, (void *)0);
1.31 markus 1009:
1.60 markus 1010: return client_loop(tty_flag, tty_flag ? options.escape_char : -1, id);
1.72 markus 1011: }
1012:
1013: int
1014: guess_identity_file_type(const char *filename)
1015: {
1016: struct stat st;
1017: Key *public;
1018: int type = KEY_RSA1; /* default */
1019:
1020: if (stat(filename, &st) < 0) {
1.73 markus 1021: /* ignore this key */
1.72 markus 1022: return KEY_UNSPEC;
1023: }
1024: public = key_new(type);
1025: if (!load_public_key(filename, public, NULL)) {
1026: /* ok, so we will assume this is 'some' key */
1027: type = KEY_UNSPEC;
1028: }
1029: key_free(public);
1030: return type;
1.1 deraadt 1031: }
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