Annotation of src/usr.bin/ssh/ssh.c, Revision 1.109
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"
1.109 ! markus 42: RCSID("$OpenBSD: ssh.c,v 1.108 2001/04/07 08:55:18 markus Exp $");
1.49 markus 43:
44: #include <openssl/evp.h>
1.72 markus 45: #include <openssl/err.h>
1.1 deraadt 46:
1.84 markus 47: #include "ssh.h"
48: #include "ssh1.h"
49: #include "ssh2.h"
50: #include "compat.h"
51: #include "cipher.h"
1.1 deraadt 52: #include "xmalloc.h"
53: #include "packet.h"
54: #include "buffer.h"
55: #include "uidswap.h"
1.44 markus 56: #include "channels.h"
1.49 markus 57: #include "key.h"
1.58 markus 58: #include "authfd.h"
1.49 markus 59: #include "authfile.h"
1.83 markus 60: #include "pathnames.h"
1.81 markus 61: #include "clientloop.h"
1.84 markus 62: #include "log.h"
63: #include "readconf.h"
64: #include "sshconnect.h"
65: #include "tildexpand.h"
1.89 markus 66: #include "dispatch.h"
1.84 markus 67: #include "misc.h"
1.95 markus 68: #include "kex.h"
69: #include "mac.h"
1.49 markus 70:
71: extern char *__progname;
1.1 deraadt 72:
1.37 markus 73: /* Flag indicating whether IPv4 or IPv6. This can be set on the command line.
74: Default value is AF_UNSPEC means both IPv4 and IPv6. */
75: int IPv4or6 = AF_UNSPEC;
76:
1.31 markus 77: /* Flag indicating whether debug mode is on. This can be set on the command line. */
1.1 deraadt 78: int debug_flag = 0;
79:
1.46 markus 80: /* Flag indicating whether a tty should be allocated */
1.1 deraadt 81: int tty_flag = 0;
1.79 markus 82: int no_tty_flag = 0;
83: int force_tty_flag = 0;
1.1 deraadt 84:
1.45 markus 85: /* don't exec a shell */
86: int no_shell_flag = 0;
87:
1.33 markus 88: /*
89: * Flag indicating that nothing should be read from stdin. This can be set
90: * on the command line.
91: */
1.1 deraadt 92: int stdin_null_flag = 0;
93:
1.33 markus 94: /*
95: * Flag indicating that ssh should fork after authentication. This is useful
96: * so that the pasphrase can be entered manually, and then ssh goes to the
97: * background.
98: */
1.1 deraadt 99: int fork_after_authentication_flag = 0;
100:
1.33 markus 101: /*
102: * General data structure for command line options and options configurable
103: * in configuration files. See readconf.h.
104: */
1.1 deraadt 105: Options options;
106:
1.33 markus 107: /*
108: * Name of the host we are connecting to. This is the name given on the
109: * command line, or the HostName specified for the user-supplied name in a
110: * configuration file.
111: */
1.1 deraadt 112: char *host;
113:
1.22 provos 114: /* socket address the host resolves to */
1.37 markus 115: struct sockaddr_storage hostaddr;
1.22 provos 116:
1.33 markus 117: /*
118: * Flag to indicate that we have received a window change signal which has
119: * not yet been processed. This will cause a message indicating the new
120: * window size to be sent to the server a little later. This is volatile
121: * because this is updated in a signal handler.
122: */
1.1 deraadt 123: volatile int received_window_change_signal = 0;
124:
125: /* Host private key. */
1.105 markus 126: Key *host_private_key = NULL;
1.1 deraadt 127:
1.10 dugsong 128: /* Original real UID. */
129: uid_t original_real_uid;
1.1 deraadt 130:
1.45 markus 131: /* command to be executed */
132: Buffer command;
133:
1.85 djm 134: /* Should we execute a command or invoke a subsystem? */
135: int subsystem_flag = 0;
136:
1.1 deraadt 137: /* Prints a help message to the user. This function never returns. */
138:
1.2 provos 139: void
1.93 itojun 140: usage(void)
1.1 deraadt 141: {
1.76 markus 142: fprintf(stderr, "Usage: %s [options] host [command]\n", __progname);
1.31 markus 143: fprintf(stderr, "Options:\n");
144: fprintf(stderr, " -l user Log in using this user name.\n");
1.93 itojun 145: fprintf(stderr, " -n Redirect input from " _PATH_DEVNULL ".\n");
1.53 markus 146: fprintf(stderr, " -A Enable authentication agent forwarding.\n");
1.31 markus 147: fprintf(stderr, " -a Disable authentication agent forwarding.\n");
1.9 dugsong 148: #ifdef AFS
1.31 markus 149: fprintf(stderr, " -k Disable Kerberos ticket and AFS token forwarding.\n");
150: #endif /* AFS */
1.88 stevesk 151: fprintf(stderr, " -X Enable X11 connection forwarding.\n");
1.31 markus 152: fprintf(stderr, " -x Disable X11 connection forwarding.\n");
1.99 deraadt 153: fprintf(stderr, " -i file Identity for public key authentication "
154: "(default: ~/.ssh/identity)\n");
1.31 markus 155: fprintf(stderr, " -t Tty; allocate a tty even if command is given.\n");
1.45 markus 156: fprintf(stderr, " -T Do not allocate a tty.\n");
1.31 markus 157: fprintf(stderr, " -v Verbose; display verbose debugging messages.\n");
1.66 markus 158: fprintf(stderr, " Multiple -v increases verbosity.\n");
1.31 markus 159: fprintf(stderr, " -V Display version number only.\n");
160: fprintf(stderr, " -P Don't allocate a privileged port.\n");
161: fprintf(stderr, " -q Quiet; don't display any warning messages.\n");
162: fprintf(stderr, " -f Fork into background after authentication.\n");
163: fprintf(stderr, " -e char Set escape character; ``none'' = disable (default: ~).\n");
164:
165: fprintf(stderr, " -c cipher Select encryption algorithm: "
1.99 deraadt 166: "``3des'', ``blowfish''\n");
1.102 stevesk 167: fprintf(stderr, " -m macs Specify MAC algorithms for protocol version 2.\n");
1.31 markus 168: fprintf(stderr, " -p port Connect to this port. Server must be on the same port.\n");
169: fprintf(stderr, " -L listen-port:host:port Forward local port to remote address\n");
170: fprintf(stderr, " -R listen-port:host:port Forward remote port to local address\n");
1.76 markus 171: fprintf(stderr, " These cause %s to listen for connections on a port, and\n", __progname);
1.31 markus 172: fprintf(stderr, " forward them to the other side by connecting to host:port.\n");
1.108 markus 173: fprintf(stderr, " -D port Dynamically forward local port to multiple remote addresses.\n");
174: fprintf(stderr, " Allows SSH to act as an application-layer proxy.\n");
175: fprintf(stderr, " Protocols Supported: SOCKS4\n");
1.31 markus 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");
1.31 markus 185: exit(1);
1.1 deraadt 186: }
187:
1.32 deraadt 188: /*
189: * Connects to the given host using rsh (or prints an error message and exits
190: * if rsh is not available). This function never returns.
191: */
1.2 provos 192: void
1.31 markus 193: rsh_connect(char *host, char *user, Buffer * command)
1.1 deraadt 194: {
1.31 markus 195: char *args[10];
196: int i;
197:
198: log("Using rsh. WARNING: Connection will not be encrypted.");
199: /* Build argument list for rsh. */
200: i = 0;
201: args[i++] = _PATH_RSH;
202: /* host may have to come after user on some systems */
203: args[i++] = host;
204: if (user) {
205: args[i++] = "-l";
206: args[i++] = user;
207: }
208: if (buffer_len(command) > 0) {
209: buffer_append(command, "\0", 1);
210: args[i++] = buffer_ptr(command);
211: }
212: args[i++] = NULL;
213: if (debug_flag) {
214: for (i = 0; args[i]; i++) {
215: if (i != 0)
216: fprintf(stderr, " ");
217: fprintf(stderr, "%s", args[i]);
218: }
219: fprintf(stderr, "\n");
220: }
221: execv(_PATH_RSH, args);
222: perror(_PATH_RSH);
223: exit(1);
1.1 deraadt 224: }
225:
1.72 markus 226: int ssh_session(void);
227: int ssh_session2(void);
1.104 markus 228: void load_public_identity_files(void);
1.45 markus 229:
1.32 deraadt 230: /*
231: * Main program for the ssh client.
232: */
1.2 provos 233: int
234: main(int ac, char **av)
1.1 deraadt 235: {
1.45 markus 236: int i, opt, optind, exit_status, ok;
1.35 markus 237: u_short fwd_port, fwd_host_port;
1.109 ! markus 238: char *optarg, *cp, *endofnumber, buf[256];
1.31 markus 239: struct stat st;
1.98 markus 240: struct passwd *pw;
1.45 markus 241: int dummy;
1.31 markus 242: uid_t original_effective_uid;
243:
1.33 markus 244: /*
245: * Save the original real uid. It will be needed later (uid-swapping
246: * may clobber the real uid).
247: */
1.31 markus 248: original_real_uid = getuid();
249: original_effective_uid = geteuid();
250:
251: /* If we are installed setuid root be careful to not drop core. */
252: if (original_real_uid != original_effective_uid) {
253: struct rlimit rlim;
254: rlim.rlim_cur = rlim.rlim_max = 0;
255: if (setrlimit(RLIMIT_CORE, &rlim) < 0)
256: fatal("setrlimit failed: %.100s", strerror(errno));
1.1 deraadt 257: }
1.107 markus 258: /* Get user data. */
259: pw = getpwuid(original_real_uid);
260: if (!pw) {
261: log("You don't exist, go away!");
262: exit(1);
263: }
264: /* Take a copy of the returned structure. */
265: pw = pwcopy(pw);
266:
1.33 markus 267: /*
268: * Use uid-swapping to give up root privileges for the duration of
269: * option processing. We will re-instantiate the rights when we are
270: * ready to create the privileged port, and will permanently drop
271: * them when the port has been created (actually, when the connection
272: * has been made, as we may need to create the port several times).
273: */
1.107 markus 274: temporarily_use_uid(pw);
1.31 markus 275:
1.33 markus 276: /*
277: * Set our umask to something reasonable, as some files are created
278: * with the default umask. This will make them world-readable but
279: * writable only by the owner, which is ok for all files for which we
280: * don't set the modes explicitly.
281: */
1.31 markus 282: umask(022);
283:
284: /* Initialize option structure to indicate that no values have been set. */
285: initialize_options(&options);
286:
287: /* Parse command-line arguments. */
288: host = NULL;
289:
290: for (optind = 1; optind < ac; optind++) {
291: if (av[optind][0] != '-') {
292: if (host)
293: break;
294: if ((cp = strchr(av[optind], '@'))) {
1.48 markus 295: if(cp == av[optind])
296: usage();
1.31 markus 297: options.user = av[optind];
298: *cp = '\0';
299: host = ++cp;
300: } else
301: host = av[optind];
302: continue;
303: }
304: opt = av[optind][1];
305: if (!opt)
306: usage();
1.108 markus 307: if (strchr("eilcmpLRDo", opt)) { /* options with arguments */
1.31 markus 308: optarg = av[optind] + 2;
309: if (strcmp(optarg, "") == 0) {
310: if (optind >= ac - 1)
311: usage();
312: optarg = av[++optind];
313: }
314: } else {
315: if (av[optind][2])
316: usage();
317: optarg = NULL;
318: }
319: switch (opt) {
1.91 jakob 320: case '1':
321: options.protocol = SSH_PROTO_1;
322: break;
1.47 markus 323: case '2':
324: options.protocol = SSH_PROTO_2;
325: break;
1.37 markus 326: case '4':
327: IPv4or6 = AF_INET;
328: break;
329: case '6':
330: IPv4or6 = AF_INET6;
331: break;
1.31 markus 332: case 'n':
333: stdin_null_flag = 1;
334: break;
335: case 'f':
336: fork_after_authentication_flag = 1;
337: stdin_null_flag = 1;
338: break;
339: case 'x':
340: options.forward_x11 = 0;
341: break;
342: case 'X':
343: options.forward_x11 = 1;
344: break;
345: case 'g':
346: options.gateway_ports = 1;
347: break;
348: case 'P':
349: options.use_privileged_port = 0;
350: break;
351: case 'a':
352: options.forward_agent = 0;
1.53 markus 353: break;
354: case 'A':
355: options.forward_agent = 1;
1.31 markus 356: break;
1.9 dugsong 357: #ifdef AFS
1.31 markus 358: case 'k':
359: options.kerberos_tgt_passing = 0;
360: options.afs_token_passing = 0;
361: break;
1.1 deraadt 362: #endif
1.31 markus 363: case 'i':
364: if (stat(optarg, &st) < 0) {
365: fprintf(stderr, "Warning: Identity file %s does not exist.\n",
1.72 markus 366: optarg);
1.31 markus 367: break;
368: }
369: if (options.num_identity_files >= SSH_MAX_IDENTITY_FILES)
370: fatal("Too many identity files specified (max %d)",
1.72 markus 371: SSH_MAX_IDENTITY_FILES);
372: options.identity_files[options.num_identity_files++] = xstrdup(optarg);
1.31 markus 373: break;
374: case 't':
1.79 markus 375: if (tty_flag)
376: force_tty_flag = 1;
1.31 markus 377: tty_flag = 1;
378: break;
379: case 'v':
1.66 markus 380: if (0 == debug_flag) {
381: debug_flag = 1;
382: options.log_level = SYSLOG_LEVEL_DEBUG1;
383: } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) {
384: options.log_level++;
385: break;
386: } else {
1.103 millert 387: fatal("Too high debugging level.");
1.66 markus 388: }
389: /* fallthrough */
1.31 markus 390: case 'V':
1.96 deraadt 391: fprintf(stderr,
392: "%s, SSH protocols %d.%d/%d.%d, OpenSSL 0x%8.8lx\n",
1.46 markus 393: SSH_VERSION,
394: PROTOCOL_MAJOR_1, PROTOCOL_MINOR_1,
1.96 deraadt 395: PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2,
396: SSLeay());
1.31 markus 397: if (opt == 'V')
398: exit(0);
399: break;
400: case 'q':
401: options.log_level = SYSLOG_LEVEL_QUIET;
402: break;
403: case 'e':
404: if (optarg[0] == '^' && optarg[2] == 0 &&
1.78 markus 405: (u_char) optarg[1] >= 64 && (u_char) optarg[1] < 128)
406: options.escape_char = (u_char) optarg[1] & 31;
1.31 markus 407: else if (strlen(optarg) == 1)
1.78 markus 408: options.escape_char = (u_char) optarg[0];
1.31 markus 409: else if (strcmp(optarg, "none") == 0)
410: options.escape_char = -2;
411: else {
412: fprintf(stderr, "Bad escape character '%s'.\n", optarg);
413: exit(1);
414: }
415: break;
416: case 'c':
1.49 markus 417: if (ciphers_valid(optarg)) {
418: /* SSH2 only */
419: options.ciphers = xstrdup(optarg);
1.51 markus 420: options.cipher = SSH_CIPHER_ILLEGAL;
1.49 markus 421: } else {
422: /* SSH1 only */
1.74 markus 423: options.cipher = cipher_number(optarg);
424: if (options.cipher == -1) {
1.49 markus 425: fprintf(stderr, "Unknown cipher type '%s'\n", optarg);
426: exit(1);
427: }
1.74 markus 428: if (options.cipher == SSH_CIPHER_3DES) {
429: options.ciphers = "3des-cbc";
430: } else if (options.cipher == SSH_CIPHER_BLOWFISH) {
431: options.ciphers = "blowfish-cbc";
432: } else {
433: options.ciphers = (char *)-1;
434: }
1.95 markus 435: }
436: break;
437: case 'm':
438: if (mac_valid(optarg))
439: options.macs = xstrdup(optarg);
440: else {
441: fprintf(stderr, "Unknown mac type '%s'\n", optarg);
442: exit(1);
1.31 markus 443: }
444: break;
445: case 'p':
1.109 ! markus 446: options.port = strtol(optarg, &endofnumber, 0);
! 447: if (optarg == endofnumber) {
! 448: fprintf(stderr, "Bad port '%s'\n", optarg);
! 449: exit(1);
! 450: }
1.31 markus 451: break;
452: case 'l':
453: options.user = optarg;
454: break;
455: case 'R':
1.37 markus 456: if (sscanf(optarg, "%hu/%255[^/]/%hu", &fwd_port, buf,
457: &fwd_host_port) != 3 &&
458: sscanf(optarg, "%hu:%255[^:]:%hu", &fwd_port, buf,
459: &fwd_host_port) != 3) {
1.31 markus 460: fprintf(stderr, "Bad forwarding specification '%s'.\n", optarg);
461: usage();
462: /* NOTREACHED */
463: }
464: add_remote_forward(&options, fwd_port, buf, fwd_host_port);
465: break;
466: case 'L':
1.37 markus 467: if (sscanf(optarg, "%hu/%255[^/]/%hu", &fwd_port, buf,
468: &fwd_host_port) != 3 &&
469: sscanf(optarg, "%hu:%255[^:]:%hu", &fwd_port, buf,
470: &fwd_host_port) != 3) {
1.31 markus 471: fprintf(stderr, "Bad forwarding specification '%s'.\n", optarg);
472: usage();
473: /* NOTREACHED */
474: }
475: add_local_forward(&options, fwd_port, buf, fwd_host_port);
476: break;
1.108 markus 477:
478: case 'D':
1.109 ! markus 479: fwd_port = strtol(optarg, &endofnumber, 0);
! 480: if (optarg == endofnumber) {
! 481: fprintf(stderr, "Bad port '%s'\n", optarg);
! 482: exit(1);
! 483: }
1.108 markus 484: add_local_forward(&options, fwd_port, "socks4", 0);
485: break;
486:
1.31 markus 487: case 'C':
488: options.compression = 1;
489: break;
1.45 markus 490: case 'N':
491: no_shell_flag = 1;
492: no_tty_flag = 1;
493: break;
494: case 'T':
495: no_tty_flag = 1;
496: break;
1.31 markus 497: case 'o':
498: dummy = 1;
499: if (process_config_line(&options, host ? host : "", optarg,
500: "command-line", 0, &dummy) != 0)
501: exit(1);
502: break;
1.85 djm 503: case 's':
504: subsystem_flag = 1;
505: break;
1.31 markus 506: default:
507: usage();
1.1 deraadt 508: }
1.31 markus 509: }
510:
511: /* Check that we got a host name. */
512: if (!host)
513: usage();
514:
1.54 markus 515: SSLeay_add_all_algorithms();
1.72 markus 516: ERR_load_crypto_strings();
1.31 markus 517:
518: /* Initialize the command to execute on remote host. */
519: buffer_init(&command);
1.1 deraadt 520:
1.33 markus 521: /*
522: * Save the command to execute on the remote host in a buffer. There
523: * is no limit on the length of the command, except by the maximum
524: * packet size. Also sets the tty flag if there is no command.
525: */
1.31 markus 526: if (optind == ac) {
527: /* No command specified - execute shell on a tty. */
528: tty_flag = 1;
1.85 djm 529: if (subsystem_flag) {
530: fprintf(stderr, "You must specify a subsystem to invoke.");
531: usage();
532: }
1.31 markus 533: } else {
534: /* A command has been specified. Store it into the
535: buffer. */
536: for (i = optind; i < ac; i++) {
537: if (i > optind)
538: buffer_append(&command, " ", 1);
539: buffer_append(&command, av[i], strlen(av[i]));
540: }
541: }
542:
543: /* Cannot fork to background if no command. */
1.63 markus 544: if (fork_after_authentication_flag && buffer_len(&command) == 0 && !no_shell_flag)
1.31 markus 545: fatal("Cannot fork into background without a command to execute.");
546:
547: /* Allocate a tty by default if no command specified. */
548: if (buffer_len(&command) == 0)
549: tty_flag = 1;
550:
1.75 markus 551: /* Force no tty*/
552: if (no_tty_flag)
553: tty_flag = 0;
1.31 markus 554: /* Do not allocate a tty if stdin is not a tty. */
1.79 markus 555: if (!isatty(fileno(stdin)) && !force_tty_flag) {
1.31 markus 556: if (tty_flag)
1.103 millert 557: log("Pseudo-terminal will not be allocated because stdin is not a terminal.");
1.31 markus 558: tty_flag = 0;
559: }
1.45 markus 560:
1.101 markus 561: /*
562: * Initialize "log" output. Since we are the client all output
563: * actually goes to stderr.
564: */
565: log_init(av[0], SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_USER, 1);
1.31 markus 566:
567: /* Read per-user configuration file. */
1.83 markus 568: snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir, _PATH_SSH_USER_CONFFILE);
1.31 markus 569: read_config_file(buf, host, &options);
570:
571: /* Read systemwide configuration file. */
1.83 markus 572: read_config_file(_PATH_HOST_CONFIG_FILE, host, &options);
1.31 markus 573:
574: /* Fill configuration defaults. */
575: fill_default_options(&options);
576:
577: /* reinit */
1.101 markus 578: log_init(av[0], options.log_level, SYSLOG_FACILITY_USER, 1);
1.31 markus 579:
580: if (options.user == NULL)
581: options.user = xstrdup(pw->pw_name);
582:
583: if (options.hostname != NULL)
584: host = options.hostname;
585:
586: /* Disable rhosts authentication if not running as root. */
587: if (original_effective_uid != 0 || !options.use_privileged_port) {
1.77 markus 588: debug("Rhosts Authentication disabled, "
1.71 markus 589: "originating port will not be trusted.");
1.31 markus 590: options.rhosts_authentication = 0;
591: }
1.33 markus 592: /*
593: * If using rsh has been selected, exec it now (without trying
594: * anything else). Note that we must release privileges first.
595: */
1.31 markus 596: if (options.use_rsh) {
1.33 markus 597: /*
598: * Restore our superuser privileges. This must be done
599: * before permanently setting the uid.
600: */
1.31 markus 601: restore_uid();
602:
603: /* Switch to the original uid permanently. */
1.107 markus 604: permanently_set_uid(pw);
1.31 markus 605:
606: /* Execute rsh. */
607: rsh_connect(host, options.user, &command);
608: fatal("rsh_connect returned");
609: }
610: /* Restore our superuser privileges. */
611: restore_uid();
612:
1.77 markus 613: /* Open a connection to the remote host. */
1.31 markus 614:
615: ok = ssh_connect(host, &hostaddr, options.port,
1.77 markus 616: options.connection_attempts,
617: original_effective_uid != 0 || !options.use_privileged_port,
1.107 markus 618: pw, options.proxy_command);
1.31 markus 619:
1.33 markus 620: /*
621: * If we successfully made the connection, load the host private key
622: * in case we will need it later for combined rsa-rhosts
623: * authentication. This must be done before releasing extra
624: * privileges, because the file is only readable by root.
625: */
1.49 markus 626: if (ok && (options.protocol & SSH_PROTO_1)) {
1.105 markus 627: host_private_key = key_load_private_type(KEY_RSA1,
628: _PATH_HOST_KEY_FILE, "", NULL);
1.31 markus 629: }
1.33 markus 630: /*
631: * Get rid of any extra privileges that we may have. We will no
632: * longer need them. Also, extra privileges could make it very hard
633: * to read identity files and other non-world-readable files from the
634: * user's home directory if it happens to be on a NFS volume where
635: * root is mapped to nobody.
636: */
637:
638: /*
639: * Note that some legacy systems need to postpone the following call
640: * to permanently_set_uid() until the private hostkey is destroyed
641: * with RSA_free(). Otherwise the calling user could ptrace() the
642: * process, read the private hostkey and impersonate the host.
643: * OpenBSD does not allow ptracing of setuid processes.
644: */
1.107 markus 645: permanently_set_uid(pw);
1.31 markus 646:
1.33 markus 647: /*
648: * Now that we are back to our own permissions, create ~/.ssh
649: * directory if it doesn\'t already exist.
650: */
1.83 markus 651: snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir, _PATH_SSH_USER_DIR);
1.31 markus 652: if (stat(buf, &st) < 0)
1.57 djm 653: if (mkdir(buf, 0700) < 0)
1.31 markus 654: error("Could not create directory '%.200s'.", buf);
655:
656: /* Check if the connection failed, and try "rsh" if appropriate. */
657: if (!ok) {
658: if (options.port != 0)
1.35 markus 659: log("Secure connection to %.100s on port %hu refused%.100s.",
1.31 markus 660: host, options.port,
661: options.fallback_to_rsh ? "; reverting to insecure method" : "");
662: else
663: log("Secure connection to %.100s refused%.100s.", host,
664: options.fallback_to_rsh ? "; reverting to insecure method" : "");
665:
666: if (options.fallback_to_rsh) {
667: rsh_connect(host, options.user, &command);
668: fatal("rsh_connect returned");
669: }
670: exit(1);
671: }
1.104 markus 672: /* load options.identity_files */
673: load_public_identity_files();
674:
675: /* Expand ~ in known host file names. */
676: /* XXX mem-leaks: */
1.72 markus 677: options.system_hostfile =
678: tilde_expand_filename(options.system_hostfile, original_real_uid);
679: options.user_hostfile =
680: tilde_expand_filename(options.user_hostfile, original_real_uid);
681: options.system_hostfile2 =
682: tilde_expand_filename(options.system_hostfile2, original_real_uid);
683: options.user_hostfile2 =
684: tilde_expand_filename(options.user_hostfile2, original_real_uid);
1.31 markus 685:
686: /* Log into the remote system. This never returns if the login fails. */
1.107 markus 687: ssh_login(host_private_key, host, (struct sockaddr *)&hostaddr, pw);
1.31 markus 688:
689: /* We no longer need the host private key. Clear it now. */
1.105 markus 690: if (host_private_key != NULL)
691: key_free(host_private_key); /* Destroys contents safely */
1.31 markus 692:
1.45 markus 693: exit_status = compat20 ? ssh_session2() : ssh_session();
694: packet_close();
695: return exit_status;
696: }
697:
1.50 markus 698: void
699: x11_get_proto(char *proto, int proto_len, char *data, int data_len)
700: {
701: char line[512];
702: FILE *f;
703: int got_data = 0, i;
704:
1.55 markus 705: if (options.xauth_location) {
706: /* Try to get Xauthority information for the display. */
1.93 itojun 707: snprintf(line, sizeof line, "%.100s list %.200s 2>" _PATH_DEVNULL,
1.55 markus 708: options.xauth_location, getenv("DISPLAY"));
709: f = popen(line, "r");
710: if (f && fgets(line, sizeof(line), f) &&
711: sscanf(line, "%*s %s %s", proto, data) == 2)
712: got_data = 1;
713: if (f)
714: pclose(f);
715: }
1.50 markus 716: /*
717: * If we didn't get authentication data, just make up some
718: * data. The forwarding code will check the validity of the
719: * response anyway, and substitute this data. The X11
720: * server, however, will ignore this fake data and use
721: * whatever authentication mechanisms it was using otherwise
722: * for the local connection.
723: */
724: if (!got_data) {
725: u_int32_t rand = 0;
726:
727: strlcpy(proto, "MIT-MAGIC-COOKIE-1", proto_len);
728: for (i = 0; i < 16; i++) {
729: if (i % 4 == 0)
730: rand = arc4random();
731: snprintf(data + 2 * i, data_len - 2 * i, "%02x", rand & 0xff);
732: rand >>= 8;
733: }
734: }
735: }
736:
1.70 markus 737: void
738: ssh_init_forwarding(void)
739: {
1.86 markus 740: int success = 0;
1.70 markus 741: int i;
1.86 markus 742:
1.70 markus 743: /* Initiate local TCP/IP port forwardings. */
744: for (i = 0; i < options.num_local_forwards; i++) {
745: debug("Connections to local port %d forwarded to remote address %.200s:%d",
746: options.local_forwards[i].port,
747: options.local_forwards[i].host,
748: options.local_forwards[i].host_port);
1.86 markus 749: success += channel_request_local_forwarding(
1.70 markus 750: options.local_forwards[i].port,
751: options.local_forwards[i].host,
752: options.local_forwards[i].host_port,
753: options.gateway_ports);
754: }
1.86 markus 755: if (i > 0 && success == 0)
756: error("Could not request local forwarding.");
1.70 markus 757:
758: /* Initiate remote TCP/IP port forwardings. */
759: for (i = 0; i < options.num_remote_forwards; i++) {
760: debug("Connections to remote port %d forwarded to local address %.200s:%d",
761: options.remote_forwards[i].port,
762: options.remote_forwards[i].host,
763: options.remote_forwards[i].host_port);
764: channel_request_remote_forwarding(
765: options.remote_forwards[i].port,
766: options.remote_forwards[i].host,
767: options.remote_forwards[i].host_port);
768: }
769: }
770:
771: void
772: check_agent_present(void)
773: {
774: if (options.forward_agent) {
775: /* Clear agent forwarding if we don\'t have an agent. */
776: int authfd = ssh_get_authentication_socket();
777: if (authfd < 0)
778: options.forward_agent = 0;
779: else
780: ssh_close_authentication_socket(authfd);
781: }
782: }
783:
1.45 markus 784: int
785: ssh_session(void)
786: {
787: int type;
788: int plen;
789: int interactive = 0;
790: int have_tty = 0;
791: struct winsize ws;
792: char *cp;
793:
1.31 markus 794: /* Enable compression if requested. */
795: if (options.compression) {
796: debug("Requesting compression at level %d.", options.compression_level);
797:
798: if (options.compression_level < 1 || options.compression_level > 9)
799: fatal("Compression level must be from 1 (fast) to 9 (slow, best).");
800:
801: /* Send the request. */
802: packet_start(SSH_CMSG_REQUEST_COMPRESSION);
803: packet_put_int(options.compression_level);
804: packet_send();
805: packet_write_wait();
806: type = packet_read(&plen);
807: if (type == SSH_SMSG_SUCCESS)
808: packet_start_compression(options.compression_level);
809: else if (type == SSH_SMSG_FAILURE)
810: log("Warning: Remote host refused compression.");
811: else
812: packet_disconnect("Protocol error waiting for compression response.");
813: }
814: /* Allocate a pseudo tty if appropriate. */
815: if (tty_flag) {
816: debug("Requesting pty.");
817:
818: /* Start the packet. */
819: packet_start(SSH_CMSG_REQUEST_PTY);
820:
821: /* Store TERM in the packet. There is no limit on the
822: length of the string. */
823: cp = getenv("TERM");
824: if (!cp)
825: cp = "";
826: packet_put_string(cp, strlen(cp));
827:
828: /* Store window size in the packet. */
829: if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
830: memset(&ws, 0, sizeof(ws));
831: packet_put_int(ws.ws_row);
832: packet_put_int(ws.ws_col);
833: packet_put_int(ws.ws_xpixel);
834: packet_put_int(ws.ws_ypixel);
835:
836: /* Store tty modes in the packet. */
837: tty_make_modes(fileno(stdin));
838:
839: /* Send the packet, and wait for it to leave. */
840: packet_send();
841: packet_write_wait();
842:
843: /* Read response from the server. */
844: type = packet_read(&plen);
1.43 markus 845: if (type == SSH_SMSG_SUCCESS) {
1.31 markus 846: interactive = 1;
1.45 markus 847: have_tty = 1;
1.43 markus 848: } else if (type == SSH_SMSG_FAILURE)
1.31 markus 849: log("Warning: Remote host failed or refused to allocate a pseudo tty.");
850: else
851: packet_disconnect("Protocol error waiting for pty request response.");
852: }
853: /* Request X11 forwarding if enabled and DISPLAY is set. */
854: if (options.forward_x11 && getenv("DISPLAY") != NULL) {
1.50 markus 855: char proto[512], data[512];
856: /* Get reasonable local authentication information. */
857: x11_get_proto(proto, sizeof proto, data, sizeof data);
858: /* Request forwarding with authentication spoofing. */
1.31 markus 859: debug("Requesting X11 forwarding with authentication spoofing.");
1.50 markus 860: x11_request_forwarding_with_spoofing(0, proto, data);
1.31 markus 861:
862: /* Read response from the server. */
863: type = packet_read(&plen);
864: if (type == SSH_SMSG_SUCCESS) {
865: interactive = 1;
1.50 markus 866: } else if (type == SSH_SMSG_FAILURE) {
1.31 markus 867: log("Warning: Remote host denied X11 forwarding.");
1.50 markus 868: } else {
1.31 markus 869: packet_disconnect("Protocol error waiting for X11 forwarding");
1.50 markus 870: }
1.31 markus 871: }
872: /* Tell the packet module whether this is an interactive session. */
1.80 markus 873: packet_set_interactive(interactive);
1.31 markus 874:
875: /* Request authentication agent forwarding if appropriate. */
1.70 markus 876: check_agent_present();
877:
1.31 markus 878: if (options.forward_agent) {
879: debug("Requesting authentication agent forwarding.");
880: auth_request_forwarding();
881:
882: /* Read response from the server. */
883: type = packet_read(&plen);
884: packet_integrity_check(plen, 0, type);
885: if (type != SSH_SMSG_SUCCESS)
886: log("Warning: Remote host denied authentication agent forwarding.");
887: }
888:
1.70 markus 889: /* Initiate port forwardings. */
890: ssh_init_forwarding();
1.34 markus 891:
892: /* If requested, let ssh continue in the background. */
1.48 markus 893: if (fork_after_authentication_flag)
1.34 markus 894: if (daemon(1, 1) < 0)
895: fatal("daemon() failed: %.200s", strerror(errno));
1.31 markus 896:
1.33 markus 897: /*
898: * If a command was specified on the command line, execute the
899: * command now. Otherwise request the server to start a shell.
900: */
1.31 markus 901: if (buffer_len(&command) > 0) {
902: int len = buffer_len(&command);
903: if (len > 900)
904: len = 900;
905: debug("Sending command: %.*s", len, buffer_ptr(&command));
906: packet_start(SSH_CMSG_EXEC_CMD);
907: packet_put_string(buffer_ptr(&command), buffer_len(&command));
908: packet_send();
909: packet_write_wait();
910: } else {
911: debug("Requesting shell.");
912: packet_start(SSH_CMSG_EXEC_SHELL);
913: packet_send();
914: packet_write_wait();
915: }
916:
917: /* Enter the interactive session. */
1.60 markus 918: return client_loop(have_tty, tty_flag ? options.escape_char : -1, 0);
1.45 markus 919: }
920:
921: void
1.89 markus 922: client_subsystem_reply(int type, int plen, void *ctxt)
923: {
924: int id, len;
925:
926: id = packet_get_int();
927: len = buffer_len(&command);
1.100 markus 928: if (len > 900)
929: len = 900;
1.89 markus 930: packet_done();
931: if (type == SSH2_MSG_CHANNEL_FAILURE)
932: fatal("Request for subsystem '%.*s' failed on channel %d",
933: len, buffer_ptr(&command), id);
934: }
935:
936: void
1.70 markus 937: ssh_session2_callback(int id, void *arg)
1.45 markus 938: {
939: int len;
1.80 markus 940: int interactive = 0;
941:
1.87 deraadt 942: debug("client_init id %d arg %ld", id, (long)arg);
1.31 markus 943:
1.45 markus 944: if (tty_flag) {
945: struct winsize ws;
946: char *cp;
947: cp = getenv("TERM");
948: if (!cp)
949: cp = "";
950: /* Store window size in the packet. */
951: if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
952: memset(&ws, 0, sizeof(ws));
953:
954: channel_request_start(id, "pty-req", 0);
955: packet_put_cstring(cp);
956: packet_put_int(ws.ws_col);
957: packet_put_int(ws.ws_row);
958: packet_put_int(ws.ws_xpixel);
959: packet_put_int(ws.ws_ypixel);
960: packet_put_cstring(""); /* XXX: encode terminal modes */
961: packet_send();
1.80 markus 962: interactive = 1;
1.45 markus 963: /* XXX wait for reply */
964: }
1.50 markus 965: if (options.forward_x11 &&
966: getenv("DISPLAY") != NULL) {
967: char proto[512], data[512];
968: /* Get reasonable local authentication information. */
969: x11_get_proto(proto, sizeof proto, data, sizeof data);
970: /* Request forwarding with authentication spoofing. */
971: debug("Requesting X11 forwarding with authentication spoofing.");
972: x11_request_forwarding_with_spoofing(id, proto, data);
1.80 markus 973: interactive = 1;
1.50 markus 974: /* XXX wait for reply */
975: }
976:
1.70 markus 977: check_agent_present();
978: if (options.forward_agent) {
979: debug("Requesting authentication agent forwarding.");
980: channel_request_start(id, "auth-agent-req@openssh.com", 0);
981: packet_send();
982: }
983:
1.45 markus 984: len = buffer_len(&command);
985: if (len > 0) {
986: if (len > 900)
987: len = 900;
1.85 djm 988: if (subsystem_flag) {
989: debug("Sending subsystem: %.*s", len, buffer_ptr(&command));
1.89 markus 990: channel_request_start(id, "subsystem", /*want reply*/ 1);
991: /* register callback for reply */
992: /* XXX we asume that client_loop has already been called */
993: dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &client_subsystem_reply);
994: dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &client_subsystem_reply);
1.85 djm 995: } else {
996: debug("Sending command: %.*s", len, buffer_ptr(&command));
997: channel_request_start(id, "exec", 0);
998: }
1.100 markus 999: packet_put_string(buffer_ptr(&command), buffer_len(&command));
1.45 markus 1000: packet_send();
1001: } else {
1002: channel_request(id, "shell", 0);
1003: }
1004: /* channel_callback(id, SSH2_MSG_OPEN_CONFIGMATION, client_init, 0); */
1.90 markus 1005:
1.45 markus 1006: /* register different callback, etc. XXX */
1.80 markus 1007: packet_set_interactive(interactive);
1.45 markus 1008: }
1009:
1010: int
1.106 markus 1011: ssh_session2_command(void)
1.45 markus 1012: {
1.106 markus 1013: int id, window, packetmax;
1.60 markus 1014: int in, out, err;
1015:
1.62 markus 1016: if (stdin_null_flag) {
1.93 itojun 1017: in = open(_PATH_DEVNULL, O_RDONLY);
1.62 markus 1018: } else {
1019: in = dup(STDIN_FILENO);
1020: }
1.60 markus 1021: out = dup(STDOUT_FILENO);
1022: err = dup(STDERR_FILENO);
1.45 markus 1023:
1024: if (in < 0 || out < 0 || err < 0)
1.62 markus 1025: fatal("dup() in/out/err failed");
1.45 markus 1026:
1.69 markus 1027: /* enable nonblocking unless tty */
1028: if (!isatty(in))
1029: set_nonblock(in);
1030: if (!isatty(out))
1031: set_nonblock(out);
1032: if (!isatty(err))
1033: set_nonblock(err);
1034:
1.65 markus 1035: window = CHAN_SES_WINDOW_DEFAULT;
1036: packetmax = CHAN_SES_PACKET_DEFAULT;
1037: if (!tty_flag) {
1.45 markus 1038: window *= 2;
1.65 markus 1039: packetmax *=2;
1.45 markus 1040: }
1041: id = channel_new(
1042: "session", SSH_CHANNEL_OPENING, in, out, err,
1.65 markus 1043: window, packetmax, CHAN_EXTENDED_WRITE,
1.69 markus 1044: xstrdup("client-session"), /*nonblock*/0);
1.45 markus 1045:
1.106 markus 1046: debug("channel_new: %d", id);
1047:
1.45 markus 1048: channel_open(id);
1.70 markus 1049: channel_register_callback(id, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION,
1050: ssh_session2_callback, (void *)0);
1.106 markus 1051:
1052: return id;
1053: }
1054:
1055: int
1056: ssh_session2(void)
1057: {
1058: int id;
1059:
1060: /* XXX should be pre-session */
1061: ssh_init_forwarding();
1062:
1063: id = no_shell_flag ? -1 : ssh_session2_command();
1064:
1065: /* If requested, let ssh continue in the background. */
1066: if (fork_after_authentication_flag)
1067: if (daemon(1, 1) < 0)
1068: fatal("daemon() failed: %.200s", strerror(errno));
1.31 markus 1069:
1.60 markus 1070: return client_loop(tty_flag, tty_flag ? options.escape_char : -1, id);
1.72 markus 1071: }
1072:
1.104 markus 1073: void
1074: load_public_identity_files(void)
1075: {
1076: char *filename;
1077: Key *public;
1078: int i;
1079:
1080: for (i = 0; i < options.num_identity_files; i++) {
1081: filename = tilde_expand_filename(options.identity_files[i],
1082: original_real_uid);
1.105 markus 1083: public = key_load_public(filename, NULL);
1.104 markus 1084: debug("identity file %s type %d", filename,
1085: public ? public->type : -1);
1086: xfree(options.identity_files[i]);
1087: options.identity_files[i] = filename;
1088: options.identity_keys[i] = public;
1089: }
1.1 deraadt 1090: }
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