Annotation of src/usr.bin/ssh/ssh.c, Revision 1.75
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"
1.75 ! markus 42: RCSID("$OpenBSD: ssh.c,v 1.74 2000/11/23 21:03:47 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"
62:
63: extern char *__progname;
1.1 deraadt 64:
1.37 markus 65: /* Flag indicating whether IPv4 or IPv6. This can be set on the command line.
66: Default value is AF_UNSPEC means both IPv4 and IPv6. */
67: int IPv4or6 = AF_UNSPEC;
68:
1.31 markus 69: /* Flag indicating whether debug mode is on. This can be set on the command line. */
1.1 deraadt 70: int debug_flag = 0;
71:
1.46 markus 72: /* Flag indicating whether a tty should be allocated */
1.1 deraadt 73: int tty_flag = 0;
74:
1.45 markus 75: /* don't exec a shell */
76: int no_shell_flag = 0;
77: int no_tty_flag = 0;
78:
1.33 markus 79: /*
80: * Flag indicating that nothing should be read from stdin. This can be set
81: * on the command line.
82: */
1.1 deraadt 83: int stdin_null_flag = 0;
84:
1.33 markus 85: /*
86: * Flag indicating that ssh should fork after authentication. This is useful
87: * so that the pasphrase can be entered manually, and then ssh goes to the
88: * background.
89: */
1.1 deraadt 90: int fork_after_authentication_flag = 0;
91:
1.33 markus 92: /*
93: * General data structure for command line options and options configurable
94: * in configuration files. See readconf.h.
95: */
1.1 deraadt 96: Options options;
97:
1.33 markus 98: /*
99: * Name of the host we are connecting to. This is the name given on the
100: * command line, or the HostName specified for the user-supplied name in a
101: * configuration file.
102: */
1.1 deraadt 103: char *host;
104:
1.22 provos 105: /* socket address the host resolves to */
1.37 markus 106: struct sockaddr_storage hostaddr;
1.22 provos 107:
1.33 markus 108: /*
109: * Flag to indicate that we have received a window change signal which has
110: * not yet been processed. This will cause a message indicating the new
111: * window size to be sent to the server a little later. This is volatile
112: * because this is updated in a signal handler.
113: */
1.1 deraadt 114: volatile int received_window_change_signal = 0;
115:
116: /* Value of argv[0] (set in the main program). */
117: char *av0;
118:
119: /* Flag indicating whether we have a valid host private key loaded. */
120: int host_private_key_loaded = 0;
121:
122: /* Host private key. */
1.2 provos 123: RSA *host_private_key = NULL;
1.1 deraadt 124:
1.10 dugsong 125: /* Original real UID. */
126: uid_t original_real_uid;
1.1 deraadt 127:
1.45 markus 128: /* command to be executed */
129: Buffer command;
130:
1.1 deraadt 131: /* Prints a help message to the user. This function never returns. */
132:
1.2 provos 133: void
134: usage()
1.1 deraadt 135: {
1.31 markus 136: fprintf(stderr, "Usage: %s [options] host [command]\n", av0);
137: fprintf(stderr, "Options:\n");
138: fprintf(stderr, " -l user Log in using this user name.\n");
139: fprintf(stderr, " -n Redirect input from /dev/null.\n");
1.53 markus 140: fprintf(stderr, " -A Enable authentication agent forwarding.\n");
1.31 markus 141: fprintf(stderr, " -a Disable authentication agent forwarding.\n");
1.9 dugsong 142: #ifdef AFS
1.31 markus 143: fprintf(stderr, " -k Disable Kerberos ticket and AFS token forwarding.\n");
144: #endif /* AFS */
1.52 markus 145: fprintf(stderr, " -X Enable X11 connection forwarding.\n");
1.31 markus 146: fprintf(stderr, " -x Disable X11 connection forwarding.\n");
147: fprintf(stderr, " -i file Identity for RSA authentication (default: ~/.ssh/identity).\n");
148: fprintf(stderr, " -t Tty; allocate a tty even if command is given.\n");
1.45 markus 149: fprintf(stderr, " -T Do not allocate a tty.\n");
1.31 markus 150: fprintf(stderr, " -v Verbose; display verbose debugging messages.\n");
1.66 markus 151: fprintf(stderr, " Multiple -v increases verbosity.\n");
1.31 markus 152: fprintf(stderr, " -V Display version number only.\n");
153: fprintf(stderr, " -P Don't allocate a privileged port.\n");
154: fprintf(stderr, " -q Quiet; don't display any warning messages.\n");
155: fprintf(stderr, " -f Fork into background after authentication.\n");
156: fprintf(stderr, " -e char Set escape character; ``none'' = disable (default: ~).\n");
157:
158: fprintf(stderr, " -c cipher Select encryption algorithm: "
159: "``3des'', "
160: "``blowfish''\n");
161: fprintf(stderr, " -p port Connect to this port. Server must be on the same port.\n");
162: fprintf(stderr, " -L listen-port:host:port Forward local port to remote address\n");
163: fprintf(stderr, " -R listen-port:host:port Forward remote port to local address\n");
164: fprintf(stderr, " These cause %s to listen for connections on a port, and\n", av0);
165: fprintf(stderr, " forward them to the other side by connecting to host:port.\n");
166: fprintf(stderr, " -C Enable compression.\n");
1.45 markus 167: fprintf(stderr, " -N Do not execute a shell or command.\n");
1.31 markus 168: fprintf(stderr, " -g Allow remote hosts to connect to forwarded ports.\n");
1.37 markus 169: fprintf(stderr, " -4 Use IPv4 only.\n");
170: fprintf(stderr, " -6 Use IPv6 only.\n");
1.47 markus 171: fprintf(stderr, " -2 Force protocol version 2.\n");
1.31 markus 172: fprintf(stderr, " -o 'option' Process the option as if it was read from a configuration file.\n");
173: exit(1);
1.1 deraadt 174: }
175:
1.32 deraadt 176: /*
177: * Connects to the given host using rsh (or prints an error message and exits
178: * if rsh is not available). This function never returns.
179: */
1.2 provos 180: void
1.31 markus 181: rsh_connect(char *host, char *user, Buffer * command)
1.1 deraadt 182: {
1.31 markus 183: char *args[10];
184: int i;
185:
186: log("Using rsh. WARNING: Connection will not be encrypted.");
187: /* Build argument list for rsh. */
188: i = 0;
189: args[i++] = _PATH_RSH;
190: /* host may have to come after user on some systems */
191: args[i++] = host;
192: if (user) {
193: args[i++] = "-l";
194: args[i++] = user;
195: }
196: if (buffer_len(command) > 0) {
197: buffer_append(command, "\0", 1);
198: args[i++] = buffer_ptr(command);
199: }
200: args[i++] = NULL;
201: if (debug_flag) {
202: for (i = 0; args[i]; i++) {
203: if (i != 0)
204: fprintf(stderr, " ");
205: fprintf(stderr, "%s", args[i]);
206: }
207: fprintf(stderr, "\n");
208: }
209: execv(_PATH_RSH, args);
210: perror(_PATH_RSH);
211: exit(1);
1.1 deraadt 212: }
213:
1.72 markus 214: int ssh_session(void);
215: int ssh_session2(void);
216: int guess_identity_file_type(const char *filename);
1.45 markus 217:
1.32 deraadt 218: /*
219: * Main program for the ssh client.
220: */
1.2 provos 221: int
222: main(int ac, char **av)
1.1 deraadt 223: {
1.45 markus 224: int i, opt, optind, exit_status, ok;
1.35 markus 225: u_short fwd_port, fwd_host_port;
1.31 markus 226: char *optarg, *cp, buf[256];
227: struct stat st;
228: struct passwd *pw, pwcopy;
1.45 markus 229: int dummy;
1.31 markus 230: uid_t original_effective_uid;
231:
1.33 markus 232: /*
233: * Save the original real uid. It will be needed later (uid-swapping
234: * may clobber the real uid).
235: */
1.31 markus 236: original_real_uid = getuid();
237: original_effective_uid = geteuid();
238:
239: /* If we are installed setuid root be careful to not drop core. */
240: if (original_real_uid != original_effective_uid) {
241: struct rlimit rlim;
242: rlim.rlim_cur = rlim.rlim_max = 0;
243: if (setrlimit(RLIMIT_CORE, &rlim) < 0)
244: fatal("setrlimit failed: %.100s", strerror(errno));
1.1 deraadt 245: }
1.33 markus 246: /*
247: * Use uid-swapping to give up root privileges for the duration of
248: * option processing. We will re-instantiate the rights when we are
249: * ready to create the privileged port, and will permanently drop
250: * them when the port has been created (actually, when the connection
251: * has been made, as we may need to create the port several times).
252: */
1.31 markus 253: temporarily_use_uid(original_real_uid);
254:
1.33 markus 255: /*
256: * Set our umask to something reasonable, as some files are created
257: * with the default umask. This will make them world-readable but
258: * writable only by the owner, which is ok for all files for which we
259: * don't set the modes explicitly.
260: */
1.31 markus 261: umask(022);
262:
263: /* Save our own name. */
264: av0 = av[0];
265:
266: /* Initialize option structure to indicate that no values have been set. */
267: initialize_options(&options);
268:
269: /* Parse command-line arguments. */
270: host = NULL;
271:
272: /* If program name is not one of the standard names, use it as host name. */
273: if (strchr(av0, '/'))
274: cp = strrchr(av0, '/') + 1;
275: else
276: cp = av0;
1.59 deraadt 277: if (strcmp(cp, "rsh") && strcmp(cp, "ssh") && strcmp(cp, "rlogin") &&
278: strcmp(cp, "slogin") && strcmp(cp, "remsh"))
1.31 markus 279: host = cp;
280:
281: for (optind = 1; optind < ac; optind++) {
282: if (av[optind][0] != '-') {
283: if (host)
284: break;
285: if ((cp = strchr(av[optind], '@'))) {
1.48 markus 286: if(cp == av[optind])
287: usage();
1.31 markus 288: options.user = av[optind];
289: *cp = '\0';
290: host = ++cp;
291: } else
292: host = av[optind];
293: continue;
294: }
295: opt = av[optind][1];
296: if (!opt)
297: usage();
298: if (strchr("eilcpLRo", opt)) { /* options with arguments */
299: optarg = av[optind] + 2;
300: if (strcmp(optarg, "") == 0) {
301: if (optind >= ac - 1)
302: usage();
303: optarg = av[++optind];
304: }
305: } else {
306: if (av[optind][2])
307: usage();
308: optarg = NULL;
309: }
310: switch (opt) {
1.47 markus 311: case '2':
312: options.protocol = SSH_PROTO_2;
313: break;
1.37 markus 314: case '4':
315: IPv4or6 = AF_INET;
316: break;
317: case '6':
318: IPv4or6 = AF_INET6;
319: break;
1.31 markus 320: case 'n':
321: stdin_null_flag = 1;
322: break;
323: case 'f':
324: fork_after_authentication_flag = 1;
325: stdin_null_flag = 1;
326: break;
327: case 'x':
328: options.forward_x11 = 0;
329: break;
330: case 'X':
331: options.forward_x11 = 1;
332: break;
333: case 'g':
334: options.gateway_ports = 1;
335: break;
336: case 'P':
337: options.use_privileged_port = 0;
338: break;
339: case 'a':
340: options.forward_agent = 0;
1.53 markus 341: break;
342: case 'A':
343: options.forward_agent = 1;
1.31 markus 344: break;
1.9 dugsong 345: #ifdef AFS
1.31 markus 346: case 'k':
347: options.kerberos_tgt_passing = 0;
348: options.afs_token_passing = 0;
349: break;
1.1 deraadt 350: #endif
1.31 markus 351: case 'i':
352: if (stat(optarg, &st) < 0) {
353: fprintf(stderr, "Warning: Identity file %s does not exist.\n",
1.72 markus 354: optarg);
1.31 markus 355: break;
356: }
357: if (options.num_identity_files >= SSH_MAX_IDENTITY_FILES)
358: fatal("Too many identity files specified (max %d)",
1.72 markus 359: SSH_MAX_IDENTITY_FILES);
360: options.identity_files[options.num_identity_files++] = xstrdup(optarg);
1.31 markus 361: break;
362: case 't':
363: tty_flag = 1;
364: break;
365: case 'v':
1.66 markus 366: if (0 == debug_flag) {
367: debug_flag = 1;
368: options.log_level = SYSLOG_LEVEL_DEBUG1;
369: } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) {
370: options.log_level++;
371: break;
372: } else {
373: fatal("Too high debugging level.\n");
374: }
375: /* fallthrough */
1.31 markus 376: case 'V':
1.46 markus 377: fprintf(stderr, "SSH Version %s, protocol versions %d.%d/%d.%d.\n",
378: SSH_VERSION,
379: PROTOCOL_MAJOR_1, PROTOCOL_MINOR_1,
380: PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2);
1.45 markus 381: fprintf(stderr, "Compiled with SSL (0x%8.8lx).\n", SSLeay());
1.31 markus 382: if (opt == 'V')
383: exit(0);
384: break;
385: case 'q':
386: options.log_level = SYSLOG_LEVEL_QUIET;
387: break;
388: case 'e':
389: if (optarg[0] == '^' && optarg[2] == 0 &&
390: (unsigned char) optarg[1] >= 64 && (unsigned char) optarg[1] < 128)
391: options.escape_char = (unsigned char) optarg[1] & 31;
392: else if (strlen(optarg) == 1)
393: options.escape_char = (unsigned char) optarg[0];
394: else if (strcmp(optarg, "none") == 0)
395: options.escape_char = -2;
396: else {
397: fprintf(stderr, "Bad escape character '%s'.\n", optarg);
398: exit(1);
399: }
400: break;
401: case 'c':
1.49 markus 402: if (ciphers_valid(optarg)) {
403: /* SSH2 only */
404: options.ciphers = xstrdup(optarg);
1.51 markus 405: options.cipher = SSH_CIPHER_ILLEGAL;
1.49 markus 406: } else {
407: /* SSH1 only */
1.74 markus 408: options.cipher = cipher_number(optarg);
409: if (options.cipher == -1) {
1.49 markus 410: fprintf(stderr, "Unknown cipher type '%s'\n", optarg);
411: exit(1);
412: }
1.74 markus 413: if (options.cipher == SSH_CIPHER_3DES) {
414: options.ciphers = "3des-cbc";
415: } else if (options.cipher == SSH_CIPHER_BLOWFISH) {
416: options.ciphers = "blowfish-cbc";
417: } else {
418: options.ciphers = (char *)-1;
419: }
1.31 markus 420: }
421: break;
422: case 'p':
423: options.port = atoi(optarg);
424: break;
425: case 'l':
426: options.user = optarg;
427: break;
428: case 'R':
1.37 markus 429: if (sscanf(optarg, "%hu/%255[^/]/%hu", &fwd_port, buf,
430: &fwd_host_port) != 3 &&
431: sscanf(optarg, "%hu:%255[^:]:%hu", &fwd_port, buf,
432: &fwd_host_port) != 3) {
1.31 markus 433: fprintf(stderr, "Bad forwarding specification '%s'.\n", optarg);
434: usage();
435: /* NOTREACHED */
436: }
437: add_remote_forward(&options, fwd_port, buf, fwd_host_port);
438: break;
439: case 'L':
1.37 markus 440: if (sscanf(optarg, "%hu/%255[^/]/%hu", &fwd_port, buf,
441: &fwd_host_port) != 3 &&
442: sscanf(optarg, "%hu:%255[^:]:%hu", &fwd_port, buf,
443: &fwd_host_port) != 3) {
1.31 markus 444: fprintf(stderr, "Bad forwarding specification '%s'.\n", optarg);
445: usage();
446: /* NOTREACHED */
447: }
448: add_local_forward(&options, fwd_port, buf, fwd_host_port);
449: break;
450: case 'C':
451: options.compression = 1;
452: break;
1.45 markus 453: case 'N':
454: no_shell_flag = 1;
455: no_tty_flag = 1;
456: break;
457: case 'T':
458: no_tty_flag = 1;
459: break;
1.31 markus 460: case 'o':
461: dummy = 1;
462: if (process_config_line(&options, host ? host : "", optarg,
463: "command-line", 0, &dummy) != 0)
464: exit(1);
465: break;
466: default:
467: usage();
1.1 deraadt 468: }
1.31 markus 469: }
470:
471: /* Check that we got a host name. */
472: if (!host)
473: usage();
474:
1.54 markus 475: SSLeay_add_all_algorithms();
1.72 markus 476: ERR_load_crypto_strings();
1.31 markus 477:
478: /* Initialize the command to execute on remote host. */
479: buffer_init(&command);
1.1 deraadt 480:
1.33 markus 481: /*
482: * Save the command to execute on the remote host in a buffer. There
483: * is no limit on the length of the command, except by the maximum
484: * packet size. Also sets the tty flag if there is no command.
485: */
1.31 markus 486: if (optind == ac) {
487: /* No command specified - execute shell on a tty. */
488: tty_flag = 1;
489: } else {
490: /* A command has been specified. Store it into the
491: buffer. */
492: for (i = optind; i < ac; i++) {
493: if (i > optind)
494: buffer_append(&command, " ", 1);
495: buffer_append(&command, av[i], strlen(av[i]));
496: }
497: }
498:
499: /* Cannot fork to background if no command. */
1.63 markus 500: if (fork_after_authentication_flag && buffer_len(&command) == 0 && !no_shell_flag)
1.31 markus 501: fatal("Cannot fork into background without a command to execute.");
502:
503: /* Allocate a tty by default if no command specified. */
504: if (buffer_len(&command) == 0)
505: tty_flag = 1;
506:
1.75 ! markus 507: /* Force no tty*/
! 508: if (no_tty_flag)
! 509: tty_flag = 0;
1.31 markus 510: /* Do not allocate a tty if stdin is not a tty. */
511: if (!isatty(fileno(stdin))) {
512: if (tty_flag)
513: fprintf(stderr, "Pseudo-terminal will not be allocated because stdin is not a terminal.\n");
514: tty_flag = 0;
515: }
1.45 markus 516:
1.31 markus 517: /* Get user data. */
518: pw = getpwuid(original_real_uid);
519: if (!pw) {
520: fprintf(stderr, "You don't exist, go away!\n");
521: exit(1);
522: }
523: /* Take a copy of the returned structure. */
524: memset(&pwcopy, 0, sizeof(pwcopy));
525: pwcopy.pw_name = xstrdup(pw->pw_name);
526: pwcopy.pw_passwd = xstrdup(pw->pw_passwd);
527: pwcopy.pw_uid = pw->pw_uid;
528: pwcopy.pw_gid = pw->pw_gid;
1.61 millert 529: pwcopy.pw_class = xstrdup(pw->pw_class);
1.31 markus 530: pwcopy.pw_dir = xstrdup(pw->pw_dir);
531: pwcopy.pw_shell = xstrdup(pw->pw_shell);
532: pw = &pwcopy;
533:
534: /* Initialize "log" output. Since we are the client all output
535: actually goes to the terminal. */
536: log_init(av[0], options.log_level, SYSLOG_FACILITY_USER, 0);
537:
538: /* Read per-user configuration file. */
539: snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir, SSH_USER_CONFFILE);
540: read_config_file(buf, host, &options);
541:
542: /* Read systemwide configuration file. */
543: read_config_file(HOST_CONFIG_FILE, host, &options);
544:
545: /* Fill configuration defaults. */
546: fill_default_options(&options);
547:
548: /* reinit */
549: log_init(av[0], options.log_level, SYSLOG_FACILITY_USER, 0);
550:
551: if (options.user == NULL)
552: options.user = xstrdup(pw->pw_name);
553:
554: if (options.hostname != NULL)
555: host = options.hostname;
556:
557: /* Disable rhosts authentication if not running as root. */
558: if (original_effective_uid != 0 || !options.use_privileged_port) {
1.71 markus 559: debug("Rhosts Authentication methods disabled, "
560: "originating port will not be trusted.");
1.31 markus 561: options.rhosts_authentication = 0;
562: options.rhosts_rsa_authentication = 0;
563: }
1.33 markus 564: /*
565: * If using rsh has been selected, exec it now (without trying
566: * anything else). Note that we must release privileges first.
567: */
1.31 markus 568: if (options.use_rsh) {
1.33 markus 569: /*
570: * Restore our superuser privileges. This must be done
571: * before permanently setting the uid.
572: */
1.31 markus 573: restore_uid();
574:
575: /* Switch to the original uid permanently. */
576: permanently_set_uid(original_real_uid);
577:
578: /* Execute rsh. */
579: rsh_connect(host, options.user, &command);
580: fatal("rsh_connect returned");
581: }
582: /* Restore our superuser privileges. */
583: restore_uid();
584:
1.33 markus 585: /*
586: * Open a connection to the remote host. This needs root privileges
587: * if rhosts_{rsa_}authentication is enabled.
588: */
1.31 markus 589:
590: ok = ssh_connect(host, &hostaddr, options.port,
591: options.connection_attempts,
592: !options.rhosts_authentication &&
593: !options.rhosts_rsa_authentication,
594: original_real_uid,
595: options.proxy_command);
596:
1.33 markus 597: /*
598: * If we successfully made the connection, load the host private key
599: * in case we will need it later for combined rsa-rhosts
600: * authentication. This must be done before releasing extra
601: * privileges, because the file is only readable by root.
602: */
1.49 markus 603: if (ok && (options.protocol & SSH_PROTO_1)) {
604: Key k;
1.31 markus 605: host_private_key = RSA_new();
1.72 markus 606: k.type = KEY_RSA1;
1.49 markus 607: k.rsa = host_private_key;
608: if (load_private_key(HOST_KEY_FILE, "", &k, NULL))
1.31 markus 609: host_private_key_loaded = 1;
610: }
1.33 markus 611: /*
612: * Get rid of any extra privileges that we may have. We will no
613: * longer need them. Also, extra privileges could make it very hard
614: * to read identity files and other non-world-readable files from the
615: * user's home directory if it happens to be on a NFS volume where
616: * root is mapped to nobody.
617: */
618:
619: /*
620: * Note that some legacy systems need to postpone the following call
621: * to permanently_set_uid() until the private hostkey is destroyed
622: * with RSA_free(). Otherwise the calling user could ptrace() the
623: * process, read the private hostkey and impersonate the host.
624: * OpenBSD does not allow ptracing of setuid processes.
625: */
1.31 markus 626: permanently_set_uid(original_real_uid);
627:
1.33 markus 628: /*
629: * Now that we are back to our own permissions, create ~/.ssh
630: * directory if it doesn\'t already exist.
631: */
1.31 markus 632: snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir, SSH_USER_DIR);
633: if (stat(buf, &st) < 0)
1.57 djm 634: if (mkdir(buf, 0700) < 0)
1.31 markus 635: error("Could not create directory '%.200s'.", buf);
636:
637: /* Check if the connection failed, and try "rsh" if appropriate. */
638: if (!ok) {
639: if (options.port != 0)
1.35 markus 640: log("Secure connection to %.100s on port %hu refused%.100s.",
1.31 markus 641: host, options.port,
642: options.fallback_to_rsh ? "; reverting to insecure method" : "");
643: else
644: log("Secure connection to %.100s refused%.100s.", host,
645: options.fallback_to_rsh ? "; reverting to insecure method" : "");
646:
647: if (options.fallback_to_rsh) {
648: rsh_connect(host, options.user, &command);
649: fatal("rsh_connect returned");
650: }
651: exit(1);
652: }
1.72 markus 653: /* Expand ~ in options.identity_files, known host file names. */
1.49 markus 654: /* XXX mem-leaks */
1.72 markus 655: for (i = 0; i < options.num_identity_files; i++) {
1.31 markus 656: options.identity_files[i] =
1.72 markus 657: tilde_expand_filename(options.identity_files[i], original_real_uid);
658: options.identity_files_type[i] = guess_identity_file_type(options.identity_files[i]);
659: debug("identity file %s type %d", options.identity_files[i],
660: options.identity_files_type[i]);
661: }
662: options.system_hostfile =
663: tilde_expand_filename(options.system_hostfile, original_real_uid);
664: options.user_hostfile =
665: tilde_expand_filename(options.user_hostfile, original_real_uid);
666: options.system_hostfile2 =
667: tilde_expand_filename(options.system_hostfile2, original_real_uid);
668: options.user_hostfile2 =
669: tilde_expand_filename(options.user_hostfile2, original_real_uid);
1.31 markus 670:
671: /* Log into the remote system. This never returns if the login fails. */
672: ssh_login(host_private_key_loaded, host_private_key,
1.37 markus 673: host, (struct sockaddr *)&hostaddr, original_real_uid);
1.31 markus 674:
675: /* We no longer need the host private key. Clear it now. */
676: if (host_private_key_loaded)
677: RSA_free(host_private_key); /* Destroys contents safely */
678:
1.45 markus 679: exit_status = compat20 ? ssh_session2() : ssh_session();
680: packet_close();
681: return exit_status;
682: }
683:
1.50 markus 684: void
685: x11_get_proto(char *proto, int proto_len, char *data, int data_len)
686: {
687: char line[512];
688: FILE *f;
689: int got_data = 0, i;
690:
1.55 markus 691: if (options.xauth_location) {
692: /* Try to get Xauthority information for the display. */
693: snprintf(line, sizeof line, "%.100s list %.200s 2>/dev/null",
694: options.xauth_location, getenv("DISPLAY"));
695: f = popen(line, "r");
696: if (f && fgets(line, sizeof(line), f) &&
697: sscanf(line, "%*s %s %s", proto, data) == 2)
698: got_data = 1;
699: if (f)
700: pclose(f);
701: }
1.50 markus 702: /*
703: * If we didn't get authentication data, just make up some
704: * data. The forwarding code will check the validity of the
705: * response anyway, and substitute this data. The X11
706: * server, however, will ignore this fake data and use
707: * whatever authentication mechanisms it was using otherwise
708: * for the local connection.
709: */
710: if (!got_data) {
711: u_int32_t rand = 0;
712:
713: strlcpy(proto, "MIT-MAGIC-COOKIE-1", proto_len);
714: for (i = 0; i < 16; i++) {
715: if (i % 4 == 0)
716: rand = arc4random();
717: snprintf(data + 2 * i, data_len - 2 * i, "%02x", rand & 0xff);
718: rand >>= 8;
719: }
720: }
721: }
722:
1.70 markus 723: void
724: ssh_init_forwarding(void)
725: {
726: int i;
727: /* Initiate local TCP/IP port forwardings. */
728: for (i = 0; i < options.num_local_forwards; i++) {
729: debug("Connections to local port %d forwarded to remote address %.200s:%d",
730: options.local_forwards[i].port,
731: options.local_forwards[i].host,
732: options.local_forwards[i].host_port);
733: channel_request_local_forwarding(
734: options.local_forwards[i].port,
735: options.local_forwards[i].host,
736: options.local_forwards[i].host_port,
737: options.gateway_ports);
738: }
739:
740: /* Initiate remote TCP/IP port forwardings. */
741: for (i = 0; i < options.num_remote_forwards; i++) {
742: debug("Connections to remote port %d forwarded to local address %.200s:%d",
743: options.remote_forwards[i].port,
744: options.remote_forwards[i].host,
745: options.remote_forwards[i].host_port);
746: channel_request_remote_forwarding(
747: options.remote_forwards[i].port,
748: options.remote_forwards[i].host,
749: options.remote_forwards[i].host_port);
750: }
751: }
752:
753: void
754: check_agent_present(void)
755: {
756: if (options.forward_agent) {
757: /* Clear agent forwarding if we don\'t have an agent. */
758: int authfd = ssh_get_authentication_socket();
759: if (authfd < 0)
760: options.forward_agent = 0;
761: else
762: ssh_close_authentication_socket(authfd);
763: }
764: }
765:
1.45 markus 766: int
767: ssh_session(void)
768: {
769: int type;
770: int plen;
771: int interactive = 0;
772: int have_tty = 0;
773: struct winsize ws;
774: char *cp;
775:
1.31 markus 776: /* Enable compression if requested. */
777: if (options.compression) {
778: debug("Requesting compression at level %d.", options.compression_level);
779:
780: if (options.compression_level < 1 || options.compression_level > 9)
781: fatal("Compression level must be from 1 (fast) to 9 (slow, best).");
782:
783: /* Send the request. */
784: packet_start(SSH_CMSG_REQUEST_COMPRESSION);
785: packet_put_int(options.compression_level);
786: packet_send();
787: packet_write_wait();
788: type = packet_read(&plen);
789: if (type == SSH_SMSG_SUCCESS)
790: packet_start_compression(options.compression_level);
791: else if (type == SSH_SMSG_FAILURE)
792: log("Warning: Remote host refused compression.");
793: else
794: packet_disconnect("Protocol error waiting for compression response.");
795: }
796: /* Allocate a pseudo tty if appropriate. */
797: if (tty_flag) {
798: debug("Requesting pty.");
799:
800: /* Start the packet. */
801: packet_start(SSH_CMSG_REQUEST_PTY);
802:
803: /* Store TERM in the packet. There is no limit on the
804: length of the string. */
805: cp = getenv("TERM");
806: if (!cp)
807: cp = "";
808: packet_put_string(cp, strlen(cp));
809:
810: /* Store window size in the packet. */
811: if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
812: memset(&ws, 0, sizeof(ws));
813: packet_put_int(ws.ws_row);
814: packet_put_int(ws.ws_col);
815: packet_put_int(ws.ws_xpixel);
816: packet_put_int(ws.ws_ypixel);
817:
818: /* Store tty modes in the packet. */
819: tty_make_modes(fileno(stdin));
820:
821: /* Send the packet, and wait for it to leave. */
822: packet_send();
823: packet_write_wait();
824:
825: /* Read response from the server. */
826: type = packet_read(&plen);
1.43 markus 827: if (type == SSH_SMSG_SUCCESS) {
1.31 markus 828: interactive = 1;
1.45 markus 829: have_tty = 1;
1.43 markus 830: } else if (type == SSH_SMSG_FAILURE)
1.31 markus 831: log("Warning: Remote host failed or refused to allocate a pseudo tty.");
832: else
833: packet_disconnect("Protocol error waiting for pty request response.");
834: }
835: /* Request X11 forwarding if enabled and DISPLAY is set. */
836: if (options.forward_x11 && getenv("DISPLAY") != NULL) {
1.50 markus 837: char proto[512], data[512];
838: /* Get reasonable local authentication information. */
839: x11_get_proto(proto, sizeof proto, data, sizeof data);
840: /* Request forwarding with authentication spoofing. */
1.31 markus 841: debug("Requesting X11 forwarding with authentication spoofing.");
1.50 markus 842: x11_request_forwarding_with_spoofing(0, proto, data);
1.31 markus 843:
844: /* Read response from the server. */
845: type = packet_read(&plen);
846: if (type == SSH_SMSG_SUCCESS) {
847: interactive = 1;
1.50 markus 848: } else if (type == SSH_SMSG_FAILURE) {
1.31 markus 849: log("Warning: Remote host denied X11 forwarding.");
1.50 markus 850: } else {
1.31 markus 851: packet_disconnect("Protocol error waiting for X11 forwarding");
1.50 markus 852: }
1.31 markus 853: }
854: /* Tell the packet module whether this is an interactive session. */
855: packet_set_interactive(interactive, options.keepalives);
856:
857:
858: /* Request authentication agent forwarding if appropriate. */
1.70 markus 859: check_agent_present();
860:
1.31 markus 861: if (options.forward_agent) {
862: debug("Requesting authentication agent forwarding.");
863: auth_request_forwarding();
864:
865: /* Read response from the server. */
866: type = packet_read(&plen);
867: packet_integrity_check(plen, 0, type);
868: if (type != SSH_SMSG_SUCCESS)
869: log("Warning: Remote host denied authentication agent forwarding.");
870: }
871:
1.70 markus 872: /* Initiate port forwardings. */
873: ssh_init_forwarding();
1.34 markus 874:
875: /* If requested, let ssh continue in the background. */
1.48 markus 876: if (fork_after_authentication_flag)
1.34 markus 877: if (daemon(1, 1) < 0)
878: fatal("daemon() failed: %.200s", strerror(errno));
1.31 markus 879:
1.33 markus 880: /*
881: * If a command was specified on the command line, execute the
882: * command now. Otherwise request the server to start a shell.
883: */
1.31 markus 884: if (buffer_len(&command) > 0) {
885: int len = buffer_len(&command);
886: if (len > 900)
887: len = 900;
888: debug("Sending command: %.*s", len, buffer_ptr(&command));
889: packet_start(SSH_CMSG_EXEC_CMD);
890: packet_put_string(buffer_ptr(&command), buffer_len(&command));
891: packet_send();
892: packet_write_wait();
893: } else {
894: debug("Requesting shell.");
895: packet_start(SSH_CMSG_EXEC_SHELL);
896: packet_send();
897: packet_write_wait();
898: }
899:
900: /* Enter the interactive session. */
1.60 markus 901: return client_loop(have_tty, tty_flag ? options.escape_char : -1, 0);
1.45 markus 902: }
903:
904: extern void client_set_session_ident(int id);
905:
906: void
1.70 markus 907: ssh_session2_callback(int id, void *arg)
1.45 markus 908: {
909: int len;
910: debug("client_init id %d arg %d", id, (int)arg);
1.31 markus 911:
1.45 markus 912: if (no_shell_flag)
913: goto done;
914:
915: if (tty_flag) {
916: struct winsize ws;
917: char *cp;
918: cp = getenv("TERM");
919: if (!cp)
920: cp = "";
921: /* Store window size in the packet. */
922: if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
923: memset(&ws, 0, sizeof(ws));
924:
925: channel_request_start(id, "pty-req", 0);
926: packet_put_cstring(cp);
927: packet_put_int(ws.ws_col);
928: packet_put_int(ws.ws_row);
929: packet_put_int(ws.ws_xpixel);
930: packet_put_int(ws.ws_ypixel);
931: packet_put_cstring(""); /* XXX: encode terminal modes */
932: packet_send();
933: /* XXX wait for reply */
934: }
1.50 markus 935: if (options.forward_x11 &&
936: getenv("DISPLAY") != NULL) {
937: char proto[512], data[512];
938: /* Get reasonable local authentication information. */
939: x11_get_proto(proto, sizeof proto, data, sizeof data);
940: /* Request forwarding with authentication spoofing. */
941: debug("Requesting X11 forwarding with authentication spoofing.");
942: x11_request_forwarding_with_spoofing(id, proto, data);
943: /* XXX wait for reply */
944: }
945:
1.70 markus 946: check_agent_present();
947: if (options.forward_agent) {
948: debug("Requesting authentication agent forwarding.");
949: channel_request_start(id, "auth-agent-req@openssh.com", 0);
950: packet_send();
951: }
952:
1.45 markus 953: len = buffer_len(&command);
954: if (len > 0) {
955: if (len > 900)
956: len = 900;
957: debug("Sending command: %.*s", len, buffer_ptr(&command));
958: channel_request_start(id, "exec", 0);
959: packet_put_string(buffer_ptr(&command), len);
960: packet_send();
961: } else {
962: channel_request(id, "shell", 0);
963: }
964: /* channel_callback(id, SSH2_MSG_OPEN_CONFIGMATION, client_init, 0); */
965: done:
966: /* register different callback, etc. XXX */
967: client_set_session_ident(id);
968: }
969:
970: int
971: ssh_session2(void)
972: {
973: int window, packetmax, id;
1.60 markus 974: int in, out, err;
975:
1.62 markus 976: if (stdin_null_flag) {
977: in = open("/dev/null", O_RDONLY);
978: } else {
979: in = dup(STDIN_FILENO);
980: }
1.60 markus 981: out = dup(STDOUT_FILENO);
982: err = dup(STDERR_FILENO);
1.45 markus 983:
984: if (in < 0 || out < 0 || err < 0)
1.62 markus 985: fatal("dup() in/out/err failed");
1.45 markus 986:
1.69 markus 987: /* enable nonblocking unless tty */
988: if (!isatty(in))
989: set_nonblock(in);
990: if (!isatty(out))
991: set_nonblock(out);
992: if (!isatty(err))
993: set_nonblock(err);
994:
1.70 markus 995: /* XXX should be pre-session */
996: ssh_init_forwarding();
1.45 markus 997:
1.62 markus 998: /* If requested, let ssh continue in the background. */
999: if (fork_after_authentication_flag)
1000: if (daemon(1, 1) < 0)
1001: fatal("daemon() failed: %.200s", strerror(errno));
1002:
1.65 markus 1003: window = CHAN_SES_WINDOW_DEFAULT;
1004: packetmax = CHAN_SES_PACKET_DEFAULT;
1005: if (!tty_flag) {
1.45 markus 1006: window *= 2;
1.65 markus 1007: packetmax *=2;
1.45 markus 1008: }
1009: id = channel_new(
1010: "session", SSH_CHANNEL_OPENING, in, out, err,
1.65 markus 1011: window, packetmax, CHAN_EXTENDED_WRITE,
1.69 markus 1012: xstrdup("client-session"), /*nonblock*/0);
1.45 markus 1013:
1014: channel_open(id);
1.70 markus 1015: channel_register_callback(id, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION,
1016: ssh_session2_callback, (void *)0);
1.31 markus 1017:
1.60 markus 1018: return client_loop(tty_flag, tty_flag ? options.escape_char : -1, id);
1.72 markus 1019: }
1020:
1021: int
1022: guess_identity_file_type(const char *filename)
1023: {
1024: struct stat st;
1025: Key *public;
1026: int type = KEY_RSA1; /* default */
1027:
1028: if (stat(filename, &st) < 0) {
1.73 markus 1029: /* ignore this key */
1.72 markus 1030: return KEY_UNSPEC;
1031: }
1032: public = key_new(type);
1033: if (!load_public_key(filename, public, NULL)) {
1034: /* ok, so we will assume this is 'some' key */
1035: type = KEY_UNSPEC;
1036: }
1037: key_free(public);
1038: return type;
1.1 deraadt 1039: }
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