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16eb0a3b | 1 | /* $OpenBSD: sshd.c,v 1.366 2009/01/22 10:02:34 djm Exp $ */ |
3c0ef626 | 2 | /* |
3 | * Author: Tatu Ylonen <ylo@cs.hut.fi> | |
4 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland | |
5 | * All rights reserved | |
6 | * This program is the ssh daemon. It listens for connections from clients, | |
7 | * and performs authentication, executes use commands or shell, and forwards | |
8 | * information to/from the application to the user client over an encrypted | |
9 | * connection. This can also handle forwarding of X11, TCP/IP, and | |
10 | * authentication agent connections. | |
11 | * | |
12 | * As far as I am concerned, the code I have written for this software | |
13 | * can be used freely for any purpose. Any derived versions of this | |
14 | * software must be clearly marked as such, and if the derived work is | |
15 | * incompatible with the protocol description in the RFC file, it must be | |
16 | * called by a name other than "ssh" or "Secure Shell". | |
17 | * | |
18 | * SSH2 implementation: | |
2980ea68 | 19 | * Privilege Separation: |
3c0ef626 | 20 | * |
2980ea68 | 21 | * Copyright (c) 2000, 2001, 2002 Markus Friedl. All rights reserved. |
22 | * Copyright (c) 2002 Niels Provos. All rights reserved. | |
3c0ef626 | 23 | * |
24 | * Redistribution and use in source and binary forms, with or without | |
25 | * modification, are permitted provided that the following conditions | |
26 | * are met: | |
27 | * 1. Redistributions of source code must retain the above copyright | |
28 | * notice, this list of conditions and the following disclaimer. | |
29 | * 2. Redistributions in binary form must reproduce the above copyright | |
30 | * notice, this list of conditions and the following disclaimer in the | |
31 | * documentation and/or other materials provided with the distribution. | |
32 | * | |
33 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR | |
34 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES | |
35 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. | |
36 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, | |
37 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
38 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
39 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
40 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
41 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF | |
42 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
43 | */ | |
44 | ||
45 | #include "includes.h" | |
2e437378 | 46 | |
47 | #include <sys/types.h> | |
48 | #include <sys/ioctl.h> | |
49 | #include <sys/socket.h> | |
50 | #ifdef HAVE_SYS_STAT_H | |
51 | # include <sys/stat.h> | |
52 | #endif | |
53 | #ifdef HAVE_SYS_TIME_H | |
54 | # include <sys/time.h> | |
55 | #endif | |
56 | #include "openbsd-compat/sys-tree.h" | |
6f25cbdd | 57 | #include "openbsd-compat/sys-queue.h" |
2e437378 | 58 | #include <sys/wait.h> |
59 | ||
60 | #include <errno.h> | |
61 | #include <fcntl.h> | |
62 | #include <netdb.h> | |
63 | #ifdef HAVE_PATHS_H | |
64 | #include <paths.h> | |
65 | #endif | |
66 | #include <grp.h> | |
67 | #include <pwd.h> | |
68 | #include <signal.h> | |
69 | #include <stdarg.h> | |
70 | #include <stdio.h> | |
71 | #include <stdlib.h> | |
72 | #include <string.h> | |
73 | #include <unistd.h> | |
3c0ef626 | 74 | |
75 | #include <openssl/dh.h> | |
76 | #include <openssl/bn.h> | |
1e608e42 | 77 | #include <openssl/md5.h> |
2980ea68 | 78 | #include <openssl/rand.h> |
bd5d5d2a | 79 | #include "openbsd-compat/openssl-compat.h" |
80 | ||
2980ea68 | 81 | #ifdef HAVE_SECUREWARE |
82 | #include <sys/security.h> | |
83 | #include <prot.h> | |
84 | #endif | |
3c0ef626 | 85 | |
2e437378 | 86 | #include "xmalloc.h" |
3c0ef626 | 87 | #include "ssh.h" |
88 | #include "ssh1.h" | |
89 | #include "ssh2.h" | |
3c0ef626 | 90 | #include "rsa.h" |
91 | #include "sshpty.h" | |
92 | #include "packet.h" | |
3c0ef626 | 93 | #include "log.h" |
2e437378 | 94 | #include "buffer.h" |
3c0ef626 | 95 | #include "servconf.h" |
96 | #include "uidswap.h" | |
97 | #include "compat.h" | |
3c0ef626 | 98 | #include "cipher.h" |
3c0ef626 | 99 | #include "key.h" |
2e437378 | 100 | #include "kex.h" |
3c0ef626 | 101 | #include "dh.h" |
102 | #include "myproposal.h" | |
103 | #include "authfile.h" | |
104 | #include "pathnames.h" | |
105 | #include "atomicio.h" | |
106 | #include "canohost.h" | |
2e437378 | 107 | #include "hostfile.h" |
3c0ef626 | 108 | #include "auth.h" |
109 | #include "misc.h" | |
1b56ff3d | 110 | #include "msg.h" |
3c0ef626 | 111 | #include "dispatch.h" |
112 | #include "channels.h" | |
2980ea68 | 113 | #include "session.h" |
114 | #include "monitor_mm.h" | |
115 | #include "monitor.h" | |
2e437378 | 116 | #ifdef GSSAPI |
117 | #include "ssh-gss.h" | |
118 | #endif | |
2980ea68 | 119 | #include "monitor_wrap.h" |
2e437378 | 120 | #include "version.h" |
3c0ef626 | 121 | |
34fee935 | 122 | #ifdef USE_SECURITY_SESSION_API |
123 | #include <Security/AuthSession.h> | |
5598e598 | 124 | #endif |
125 | ||
3c0ef626 | 126 | #ifdef LIBWRAP |
127 | #include <tcpd.h> | |
128 | #include <syslog.h> | |
bd5d5d2a | 129 | int allow_severity; |
130 | int deny_severity; | |
3c0ef626 | 131 | #endif /* LIBWRAP */ |
132 | ||
133 | #ifndef O_NOCTTY | |
134 | #define O_NOCTTY 0 | |
135 | #endif | |
136 | ||
1b56ff3d | 137 | /* Re-exec fds */ |
138 | #define REEXEC_DEVCRYPTO_RESERVED_FD (STDERR_FILENO + 1) | |
139 | #define REEXEC_STARTUP_PIPE_FD (STDERR_FILENO + 2) | |
140 | #define REEXEC_CONFIG_PASS_FD (STDERR_FILENO + 3) | |
141 | #define REEXEC_MIN_FREE_FD (STDERR_FILENO + 4) | |
142 | ||
bd5d5d2a | 143 | int myflag = 0; |
144 | ||
145 | ||
3c0ef626 | 146 | extern char *__progname; |
3c0ef626 | 147 | |
148 | /* Server configuration options. */ | |
149 | ServerOptions options; | |
150 | ||
151 | /* Name of the server configuration file. */ | |
ae43c103 | 152 | char *config_file_name; |
3c0ef626 | 153 | |
3c0ef626 | 154 | /* |
155 | * Debug mode flag. This can be set on the command line. If debug | |
156 | * mode is enabled, extra debugging output will be sent to the system | |
157 | * log, the daemon will not go to background, and will exit after processing | |
158 | * the first connection. | |
159 | */ | |
160 | int debug_flag = 0; | |
161 | ||
162 | /* Flag indicating that the daemon should only test the configuration and keys. */ | |
163 | int test_flag = 0; | |
164 | ||
165 | /* Flag indicating that the daemon is being started from inetd. */ | |
166 | int inetd_flag = 0; | |
167 | ||
168 | /* Flag indicating that sshd should not detach and become a daemon. */ | |
169 | int no_daemon_flag = 0; | |
170 | ||
171 | /* debug goes to stderr unless inetd_flag is set */ | |
172 | int log_stderr = 0; | |
173 | ||
174 | /* Saved arguments to main(). */ | |
175 | char **saved_argv; | |
176 | int saved_argc; | |
177 | ||
1b56ff3d | 178 | /* re-exec */ |
179 | int rexeced_flag = 0; | |
180 | int rexec_flag = 1; | |
181 | int rexec_argc = 0; | |
182 | char **rexec_argv; | |
183 | ||
3c0ef626 | 184 | /* |
185 | * The sockets that the server is listening; this is used in the SIGHUP | |
186 | * signal handler. | |
187 | */ | |
188 | #define MAX_LISTEN_SOCKS 16 | |
189 | int listen_socks[MAX_LISTEN_SOCKS]; | |
190 | int num_listen_socks = 0; | |
191 | ||
192 | /* | |
193 | * the client's version string, passed by sshd2 in compat mode. if != NULL, | |
194 | * sshd will skip the version-number exchange | |
195 | */ | |
196 | char *client_version_string = NULL; | |
197 | char *server_version_string = NULL; | |
198 | ||
199 | /* for rekeying XXX fixme */ | |
200 | Kex *xxx_kex; | |
201 | ||
202 | /* | |
203 | * Any really sensitive data in the application is contained in this | |
204 | * structure. The idea is that this structure could be locked into memory so | |
205 | * that the pages do not get written into swap. However, there are some | |
206 | * problems. The private key contains BIGNUMs, and we do not (in principle) | |
207 | * have access to the internals of them, and locking just the structure is | |
208 | * not very useful. Currently, memory locking is not implemented. | |
209 | */ | |
210 | struct { | |
211 | Key *server_key; /* ephemeral server key */ | |
212 | Key *ssh1_host_key; /* ssh1 host key */ | |
213 | Key **host_keys; /* all private host keys */ | |
214 | int have_ssh1_key; | |
215 | int have_ssh2_key; | |
216 | u_char ssh1_cookie[SSH_SESSION_KEY_LENGTH]; | |
217 | } sensitive_data; | |
218 | ||
219 | /* | |
220 | * Flag indicating whether the RSA server key needs to be regenerated. | |
221 | * Is set in the SIGALRM handler and cleared when the key is regenerated. | |
222 | */ | |
1e608e42 | 223 | static volatile sig_atomic_t key_do_regen = 0; |
3c0ef626 | 224 | |
225 | /* This is set to true when a signal is received. */ | |
1e608e42 | 226 | static volatile sig_atomic_t received_sighup = 0; |
227 | static volatile sig_atomic_t received_sigterm = 0; | |
3c0ef626 | 228 | |
229 | /* session identifier, used by RSA-auth */ | |
230 | u_char session_id[16]; | |
231 | ||
232 | /* same for ssh2 */ | |
233 | u_char *session_id2 = NULL; | |
70791e56 | 234 | u_int session_id2_len = 0; |
3c0ef626 | 235 | |
236 | /* record remote hostname or ip */ | |
237 | u_int utmp_len = MAXHOSTNAMELEN; | |
238 | ||
1e608e42 | 239 | /* options.max_startup sized array of fd ints */ |
240 | int *startup_pipes = NULL; | |
241 | int startup_pipe; /* in child */ | |
242 | ||
2980ea68 | 243 | /* variables used for privilege separation */ |
2e437378 | 244 | int use_privsep = -1; |
416fd2a8 | 245 | struct monitor *pmonitor = NULL; |
2980ea68 | 246 | |
416fd2a8 | 247 | /* global authentication context */ |
248 | Authctxt *the_authctxt = NULL; | |
249 | ||
2e437378 | 250 | /* sshd_config buffer */ |
251 | Buffer cfg; | |
252 | ||
1b56ff3d | 253 | /* message to be displayed after login */ |
254 | Buffer loginmsg; | |
255 | ||
2e437378 | 256 | /* Unprivileged user */ |
257 | struct passwd *privsep_pw = NULL; | |
258 | ||
3c0ef626 | 259 | /* Prototypes for various functions defined later in this file. */ |
260 | void destroy_sensitive_data(void); | |
2980ea68 | 261 | void demote_sensitive_data(void); |
3c0ef626 | 262 | |
263 | static void do_ssh1_kex(void); | |
264 | static void do_ssh2_kex(void); | |
265 | ||
266 | /* | |
267 | * Close all listening sockets | |
268 | */ | |
269 | static void | |
270 | close_listen_socks(void) | |
271 | { | |
272 | int i; | |
ff2d7a98 | 273 | |
3c0ef626 | 274 | for (i = 0; i < num_listen_socks; i++) |
275 | close(listen_socks[i]); | |
276 | num_listen_socks = -1; | |
277 | } | |
278 | ||
1e608e42 | 279 | static void |
280 | close_startup_pipes(void) | |
281 | { | |
282 | int i; | |
ff2d7a98 | 283 | |
1e608e42 | 284 | if (startup_pipes) |
285 | for (i = 0; i < options.max_startups; i++) | |
286 | if (startup_pipes[i] != -1) | |
287 | close(startup_pipes[i]); | |
288 | } | |
289 | ||
3c0ef626 | 290 | /* |
291 | * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP; | |
292 | * the effect is to reread the configuration file (and to regenerate | |
293 | * the server key). | |
294 | */ | |
2e437378 | 295 | |
296 | /*ARGSUSED*/ | |
3c0ef626 | 297 | static void |
298 | sighup_handler(int sig) | |
299 | { | |
1e608e42 | 300 | int save_errno = errno; |
301 | ||
3c0ef626 | 302 | received_sighup = 1; |
303 | signal(SIGHUP, sighup_handler); | |
1e608e42 | 304 | errno = save_errno; |
3c0ef626 | 305 | } |
306 | ||
307 | /* | |
308 | * Called from the main program after receiving SIGHUP. | |
309 | * Restarts the server. | |
310 | */ | |
311 | static void | |
312 | sighup_restart(void) | |
313 | { | |
70791e56 | 314 | logit("Received SIGHUP; restarting."); |
3c0ef626 | 315 | close_listen_socks(); |
1e608e42 | 316 | close_startup_pipes(); |
2278ffa1 | 317 | alarm(0); /* alarm timer persists across exec */ |
3c0ef626 | 318 | execv(saved_argv[0], saved_argv); |
70791e56 | 319 | logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0], |
ff2d7a98 | 320 | strerror(errno)); |
3c0ef626 | 321 | exit(1); |
322 | } | |
323 | ||
324 | /* | |
325 | * Generic signal handler for terminating signals in the master daemon. | |
326 | */ | |
2e437378 | 327 | /*ARGSUSED*/ |
3c0ef626 | 328 | static void |
329 | sigterm_handler(int sig) | |
330 | { | |
331 | received_sigterm = sig; | |
332 | } | |
333 | ||
334 | /* | |
335 | * SIGCHLD handler. This is called whenever a child dies. This will then | |
336 | * reap any zombies left by exited children. | |
337 | */ | |
2e437378 | 338 | /*ARGSUSED*/ |
3c0ef626 | 339 | static void |
340 | main_sigchld_handler(int sig) | |
341 | { | |
342 | int save_errno = errno; | |
ff2d7a98 | 343 | pid_t pid; |
3c0ef626 | 344 | int status; |
345 | ||
2980ea68 | 346 | while ((pid = waitpid(-1, &status, WNOHANG)) > 0 || |
347 | (pid < 0 && errno == EINTR)) | |
3c0ef626 | 348 | ; |
349 | ||
350 | signal(SIGCHLD, main_sigchld_handler); | |
351 | errno = save_errno; | |
352 | } | |
353 | ||
354 | /* | |
355 | * Signal handler for the alarm after the login grace period has expired. | |
356 | */ | |
2e437378 | 357 | /*ARGSUSED*/ |
3c0ef626 | 358 | static void |
359 | grace_alarm_handler(int sig) | |
360 | { | |
416fd2a8 | 361 | if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0) |
362 | kill(pmonitor->m_pid, SIGALRM); | |
363 | ||
3c0ef626 | 364 | /* Log error and exit. */ |
2e437378 | 365 | sigdie("Timeout before authentication for %s", get_remote_ipaddr()); |
3c0ef626 | 366 | } |
367 | ||
368 | /* | |
369 | * Signal handler for the key regeneration alarm. Note that this | |
370 | * alarm only occurs in the daemon waiting for connections, and it does not | |
371 | * do anything with the private key or random state before forking. | |
372 | * Thus there should be no concurrency control/asynchronous execution | |
373 | * problems. | |
374 | */ | |
375 | static void | |
376 | generate_ephemeral_server_key(void) | |
377 | { | |
3c0ef626 | 378 | verbose("Generating %s%d bit RSA key.", |
379 | sensitive_data.server_key ? "new " : "", options.server_key_bits); | |
380 | if (sensitive_data.server_key != NULL) | |
381 | key_free(sensitive_data.server_key); | |
382 | sensitive_data.server_key = key_generate(KEY_RSA1, | |
383 | options.server_key_bits); | |
384 | verbose("RSA key generation complete."); | |
385 | ||
6f25cbdd | 386 | arc4random_buf(sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); |
3c0ef626 | 387 | arc4random_stir(); |
388 | } | |
389 | ||
2e437378 | 390 | /*ARGSUSED*/ |
3c0ef626 | 391 | static void |
392 | key_regeneration_alarm(int sig) | |
393 | { | |
394 | int save_errno = errno; | |
ff2d7a98 | 395 | |
3c0ef626 | 396 | signal(SIGALRM, SIG_DFL); |
397 | errno = save_errno; | |
398 | key_do_regen = 1; | |
399 | } | |
400 | ||
401 | static void | |
402 | sshd_exchange_identification(int sock_in, int sock_out) | |
403 | { | |
34fee935 | 404 | u_int i; |
405 | int mismatch; | |
3c0ef626 | 406 | int remote_major, remote_minor; |
407 | int major, minor; | |
6f25cbdd | 408 | char *s, *newline = "\n"; |
3c0ef626 | 409 | char buf[256]; /* Must not be larger than remote_version. */ |
410 | char remote_version[256]; /* Must be at least as big as buf. */ | |
411 | ||
412 | if ((options.protocol & SSH_PROTO_1) && | |
413 | (options.protocol & SSH_PROTO_2)) { | |
414 | major = PROTOCOL_MAJOR_1; | |
415 | minor = 99; | |
416 | } else if (options.protocol & SSH_PROTO_2) { | |
417 | major = PROTOCOL_MAJOR_2; | |
418 | minor = PROTOCOL_MINOR_2; | |
6f25cbdd | 419 | newline = "\r\n"; |
3c0ef626 | 420 | } else { |
421 | major = PROTOCOL_MAJOR_1; | |
422 | minor = PROTOCOL_MINOR_1; | |
423 | } | |
6f25cbdd | 424 | snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s%s", major, minor, |
425 | SSH_RELEASE, newline); | |
3c0ef626 | 426 | server_version_string = xstrdup(buf); |
427 | ||
70791e56 | 428 | /* Send our protocol version identification. */ |
429 | if (atomicio(vwrite, sock_out, server_version_string, | |
430 | strlen(server_version_string)) | |
431 | != strlen(server_version_string)) { | |
432 | logit("Could not write ident string to %s", get_remote_ipaddr()); | |
416fd2a8 | 433 | cleanup_exit(255); |
70791e56 | 434 | } |
435 | ||
436 | /* Read other sides version identification. */ | |
437 | memset(buf, 0, sizeof(buf)); | |
438 | for (i = 0; i < sizeof(buf) - 1; i++) { | |
439 | if (atomicio(read, sock_in, &buf[i], 1) != 1) { | |
440 | logit("Did not receive identification string from %s", | |
441 | get_remote_ipaddr()); | |
416fd2a8 | 442 | cleanup_exit(255); |
3c0ef626 | 443 | } |
70791e56 | 444 | if (buf[i] == '\r') { |
445 | buf[i] = 0; | |
446 | /* Kludge for F-Secure Macintosh < 1.0.2 */ | |
447 | if (i == 12 && | |
448 | strncmp(buf, "SSH-1.5-W1.0", 12) == 0) | |
3c0ef626 | 449 | break; |
70791e56 | 450 | continue; |
451 | } | |
452 | if (buf[i] == '\n') { | |
453 | buf[i] = 0; | |
454 | break; | |
3c0ef626 | 455 | } |
3c0ef626 | 456 | } |
70791e56 | 457 | buf[sizeof(buf) - 1] = 0; |
458 | client_version_string = xstrdup(buf); | |
3c0ef626 | 459 | |
460 | /* | |
461 | * Check that the versions match. In future this might accept | |
462 | * several versions and set appropriate flags to handle them. | |
463 | */ | |
464 | if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n", | |
465 | &remote_major, &remote_minor, remote_version) != 3) { | |
466 | s = "Protocol mismatch.\n"; | |
70791e56 | 467 | (void) atomicio(vwrite, sock_out, s, strlen(s)); |
3c0ef626 | 468 | close(sock_in); |
469 | close(sock_out); | |
70791e56 | 470 | logit("Bad protocol version identification '%.100s' from %s", |
3c0ef626 | 471 | client_version_string, get_remote_ipaddr()); |
416fd2a8 | 472 | cleanup_exit(255); |
3c0ef626 | 473 | } |
474 | debug("Client protocol version %d.%d; client software version %.100s", | |
1e608e42 | 475 | remote_major, remote_minor, remote_version); |
bd5d5d2a | 476 | logit("SSH: Server;Ltype: Version;Remote: %s-%d;Protocol: %d.%d;Client: %.100s", |
477 | get_remote_ipaddr(), get_remote_port(), | |
478 | remote_major, remote_minor, remote_version); | |
3c0ef626 | 479 | |
480 | compat_datafellows(remote_version); | |
481 | ||
e54b3d7c | 482 | if (datafellows & SSH_BUG_PROBE) { |
70791e56 | 483 | logit("probed from %s with %s. Don't panic.", |
e54b3d7c | 484 | get_remote_ipaddr(), client_version_string); |
416fd2a8 | 485 | cleanup_exit(255); |
e54b3d7c | 486 | } |
487 | ||
3c0ef626 | 488 | if (datafellows & SSH_BUG_SCANNER) { |
70791e56 | 489 | logit("scanned from %s with %s. Don't panic.", |
3c0ef626 | 490 | get_remote_ipaddr(), client_version_string); |
416fd2a8 | 491 | cleanup_exit(255); |
3c0ef626 | 492 | } |
493 | ||
494 | mismatch = 0; | |
1e608e42 | 495 | switch (remote_major) { |
3c0ef626 | 496 | case 1: |
497 | if (remote_minor == 99) { | |
498 | if (options.protocol & SSH_PROTO_2) | |
499 | enable_compat20(); | |
500 | else | |
501 | mismatch = 1; | |
502 | break; | |
503 | } | |
504 | if (!(options.protocol & SSH_PROTO_1)) { | |
505 | mismatch = 1; | |
506 | break; | |
507 | } | |
508 | if (remote_minor < 3) { | |
509 | packet_disconnect("Your ssh version is too old and " | |
510 | "is no longer supported. Please install a newer version."); | |
511 | } else if (remote_minor == 3) { | |
512 | /* note that this disables agent-forwarding */ | |
513 | enable_compat13(); | |
514 | } | |
515 | break; | |
516 | case 2: | |
517 | if (options.protocol & SSH_PROTO_2) { | |
518 | enable_compat20(); | |
519 | break; | |
520 | } | |
521 | /* FALLTHROUGH */ | |
522 | default: | |
523 | mismatch = 1; | |
524 | break; | |
525 | } | |
526 | chop(server_version_string); | |
527 | debug("Local version string %.200s", server_version_string); | |
528 | ||
529 | if (mismatch) { | |
530 | s = "Protocol major versions differ.\n"; | |
70791e56 | 531 | (void) atomicio(vwrite, sock_out, s, strlen(s)); |
3c0ef626 | 532 | close(sock_in); |
533 | close(sock_out); | |
70791e56 | 534 | logit("Protocol major versions differ for %s: %.200s vs. %.200s", |
3c0ef626 | 535 | get_remote_ipaddr(), |
536 | server_version_string, client_version_string); | |
416fd2a8 | 537 | cleanup_exit(255); |
3c0ef626 | 538 | } |
539 | } | |
540 | ||
3c0ef626 | 541 | /* Destroy the host and server keys. They will no longer be needed. */ |
542 | void | |
543 | destroy_sensitive_data(void) | |
544 | { | |
545 | int i; | |
546 | ||
547 | if (sensitive_data.server_key) { | |
548 | key_free(sensitive_data.server_key); | |
549 | sensitive_data.server_key = NULL; | |
550 | } | |
1e608e42 | 551 | for (i = 0; i < options.num_host_key_files; i++) { |
3c0ef626 | 552 | if (sensitive_data.host_keys[i]) { |
553 | key_free(sensitive_data.host_keys[i]); | |
554 | sensitive_data.host_keys[i] = NULL; | |
555 | } | |
556 | } | |
557 | sensitive_data.ssh1_host_key = NULL; | |
558 | memset(sensitive_data.ssh1_cookie, 0, SSH_SESSION_KEY_LENGTH); | |
559 | } | |
560 | ||
2980ea68 | 561 | /* Demote private to public keys for network child */ |
562 | void | |
563 | demote_sensitive_data(void) | |
564 | { | |
565 | Key *tmp; | |
566 | int i; | |
567 | ||
568 | if (sensitive_data.server_key) { | |
569 | tmp = key_demote(sensitive_data.server_key); | |
570 | key_free(sensitive_data.server_key); | |
571 | sensitive_data.server_key = tmp; | |
572 | } | |
573 | ||
574 | for (i = 0; i < options.num_host_key_files; i++) { | |
575 | if (sensitive_data.host_keys[i]) { | |
576 | tmp = key_demote(sensitive_data.host_keys[i]); | |
577 | key_free(sensitive_data.host_keys[i]); | |
578 | sensitive_data.host_keys[i] = tmp; | |
579 | if (tmp->type == KEY_RSA1) | |
580 | sensitive_data.ssh1_host_key = tmp; | |
581 | } | |
582 | } | |
583 | ||
584 | /* We do not clear ssh1_host key and cookie. XXX - Okay Niels? */ | |
585 | } | |
586 | ||
587 | static void | |
588 | privsep_preauth_child(void) | |
589 | { | |
6f25cbdd | 590 | u_int32_t rnd[256]; |
e54b3d7c | 591 | gid_t gidset[1]; |
2980ea68 | 592 | |
593 | /* Enable challenge-response authentication for privilege separation */ | |
594 | privsep_challenge_enable(); | |
595 | ||
bd5d5d2a | 596 | arc4random_stir(); |
6f25cbdd | 597 | arc4random_buf(rnd, sizeof(rnd)); |
e54b3d7c | 598 | RAND_seed(rnd, sizeof(rnd)); |
2980ea68 | 599 | |
600 | /* Demote the private keys to public keys. */ | |
601 | demote_sensitive_data(); | |
602 | ||
e54b3d7c | 603 | /* Change our root directory */ |
2980ea68 | 604 | if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1) |
605 | fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR, | |
606 | strerror(errno)); | |
607 | if (chdir("/") == -1) | |
608 | fatal("chdir(\"/\"): %s", strerror(errno)); | |
609 | ||
610 | /* Drop our privileges */ | |
2e437378 | 611 | debug3("privsep user:group %u:%u", (u_int)privsep_pw->pw_uid, |
612 | (u_int)privsep_pw->pw_gid); | |
ff2d7a98 | 613 | #if 0 |
2a304a95 | 614 | /* XXX not ready, too heavy after chroot */ |
2e437378 | 615 | do_setusercontext(privsep_pw); |
ff2d7a98 | 616 | #else |
2e437378 | 617 | gidset[0] = privsep_pw->pw_gid; |
ff2d7a98 | 618 | if (setgroups(1, gidset) < 0) |
619 | fatal("setgroups: %.100s", strerror(errno)); | |
2e437378 | 620 | permanently_set_uid(privsep_pw); |
ff2d7a98 | 621 | #endif |
2980ea68 | 622 | } |
623 | ||
416fd2a8 | 624 | static int |
625 | privsep_preauth(Authctxt *authctxt) | |
2980ea68 | 626 | { |
2980ea68 | 627 | int status; |
628 | pid_t pid; | |
629 | ||
630 | /* Set up unprivileged child process to deal with network data */ | |
631 | pmonitor = monitor_init(); | |
632 | /* Store a pointer to the kex for later rekeying */ | |
633 | pmonitor->m_pkex = &xxx_kex; | |
634 | ||
635 | pid = fork(); | |
636 | if (pid == -1) { | |
637 | fatal("fork of unprivileged child failed"); | |
638 | } else if (pid != 0) { | |
ff2d7a98 | 639 | debug2("Network child is on pid %ld", (long)pid); |
2980ea68 | 640 | |
641 | close(pmonitor->m_recvfd); | |
416fd2a8 | 642 | pmonitor->m_pid = pid; |
643 | monitor_child_preauth(authctxt, pmonitor); | |
2980ea68 | 644 | close(pmonitor->m_sendfd); |
645 | ||
646 | /* Sync memory */ | |
647 | monitor_sync(pmonitor); | |
648 | ||
649 | /* Wait for the child's exit status */ | |
650 | while (waitpid(pid, &status, 0) < 0) | |
651 | if (errno != EINTR) | |
652 | break; | |
416fd2a8 | 653 | return (1); |
2980ea68 | 654 | } else { |
655 | /* child */ | |
656 | ||
657 | close(pmonitor->m_sendfd); | |
658 | ||
659 | /* Demote the child */ | |
660 | if (getuid() == 0 || geteuid() == 0) | |
661 | privsep_preauth_child(); | |
662 | setproctitle("%s", "[net]"); | |
663 | } | |
416fd2a8 | 664 | return (0); |
2980ea68 | 665 | } |
666 | ||
667 | static void | |
668 | privsep_postauth(Authctxt *authctxt) | |
669 | { | |
bd5d5d2a | 670 | u_int32_t rnd[256]; |
bd5d5d2a | 671 | |
e54b3d7c | 672 | #ifdef DISABLE_FD_PASSING |
ff2d7a98 | 673 | if (1) { |
674 | #else | |
2980ea68 | 675 | if (authctxt->pw->pw_uid == 0 || options.use_login) { |
ff2d7a98 | 676 | #endif |
2980ea68 | 677 | /* File descriptor passing is broken or root login */ |
2980ea68 | 678 | use_privsep = 0; |
e00da40d | 679 | goto skip; |
2980ea68 | 680 | } |
681 | ||
682 | /* New socket pair */ | |
683 | monitor_reinit(pmonitor); | |
684 | ||
685 | pmonitor->m_pid = fork(); | |
686 | if (pmonitor->m_pid == -1) | |
687 | fatal("fork of unprivileged child failed"); | |
688 | else if (pmonitor->m_pid != 0) { | |
6f25cbdd | 689 | verbose("User child is on pid %ld", (long)pmonitor->m_pid); |
2980ea68 | 690 | close(pmonitor->m_recvfd); |
1b56ff3d | 691 | buffer_clear(&loginmsg); |
2980ea68 | 692 | monitor_child_postauth(pmonitor); |
693 | ||
694 | /* NEVERREACHED */ | |
695 | exit(0); | |
696 | } | |
697 | ||
698 | close(pmonitor->m_sendfd); | |
699 | ||
700 | /* Demote the private keys to public keys. */ | |
701 | demote_sensitive_data(); | |
702 | ||
bd5d5d2a | 703 | arc4random_stir(); |
6f25cbdd | 704 | arc4random_buf(rnd, sizeof(rnd)); |
bd5d5d2a | 705 | RAND_seed(rnd, sizeof(rnd)); |
706 | ||
2980ea68 | 707 | /* Drop privileges */ |
708 | do_setusercontext(authctxt->pw); | |
709 | ||
e00da40d | 710 | skip: |
2980ea68 | 711 | /* It is safe now to apply the key state */ |
712 | monitor_apply_keystate(pmonitor); | |
34fee935 | 713 | |
714 | /* | |
715 | * Tell the packet layer that authentication was successful, since | |
716 | * this information is not part of the key state. | |
717 | */ | |
718 | packet_set_authenticated(); | |
2980ea68 | 719 | } |
720 | ||
3c0ef626 | 721 | static char * |
722 | list_hostkey_types(void) | |
723 | { | |
1e608e42 | 724 | Buffer b; |
416fd2a8 | 725 | const char *p; |
726 | char *ret; | |
3c0ef626 | 727 | int i; |
1e608e42 | 728 | |
729 | buffer_init(&b); | |
730 | for (i = 0; i < options.num_host_key_files; i++) { | |
3c0ef626 | 731 | Key *key = sensitive_data.host_keys[i]; |
732 | if (key == NULL) | |
733 | continue; | |
1e608e42 | 734 | switch (key->type) { |
3c0ef626 | 735 | case KEY_RSA: |
736 | case KEY_DSA: | |
1e608e42 | 737 | if (buffer_len(&b) > 0) |
738 | buffer_append(&b, ",", 1); | |
739 | p = key_ssh_name(key); | |
740 | buffer_append(&b, p, strlen(p)); | |
3c0ef626 | 741 | break; |
742 | } | |
743 | } | |
1e608e42 | 744 | buffer_append(&b, "\0", 1); |
416fd2a8 | 745 | ret = xstrdup(buffer_ptr(&b)); |
1e608e42 | 746 | buffer_free(&b); |
416fd2a8 | 747 | debug("list_hostkey_types: %s", ret); |
748 | return ret; | |
3c0ef626 | 749 | } |
750 | ||
2980ea68 | 751 | Key * |
3c0ef626 | 752 | get_hostkey_by_type(int type) |
753 | { | |
754 | int i; | |
ff2d7a98 | 755 | |
1e608e42 | 756 | for (i = 0; i < options.num_host_key_files; i++) { |
3c0ef626 | 757 | Key *key = sensitive_data.host_keys[i]; |
758 | if (key != NULL && key->type == type) | |
759 | return key; | |
760 | } | |
761 | return NULL; | |
762 | } | |
763 | ||
2980ea68 | 764 | Key * |
765 | get_hostkey_by_index(int ind) | |
766 | { | |
767 | if (ind < 0 || ind >= options.num_host_key_files) | |
768 | return (NULL); | |
769 | return (sensitive_data.host_keys[ind]); | |
770 | } | |
771 | ||
772 | int | |
773 | get_hostkey_index(Key *key) | |
774 | { | |
775 | int i; | |
ff2d7a98 | 776 | |
2980ea68 | 777 | for (i = 0; i < options.num_host_key_files; i++) { |
778 | if (key == sensitive_data.host_keys[i]) | |
779 | return (i); | |
780 | } | |
781 | return (-1); | |
782 | } | |
783 | ||
3c0ef626 | 784 | /* |
785 | * returns 1 if connection should be dropped, 0 otherwise. | |
786 | * dropping starts at connection #max_startups_begin with a probability | |
787 | * of (max_startups_rate/100). the probability increases linearly until | |
788 | * all connections are dropped for startups > max_startups | |
789 | */ | |
790 | static int | |
791 | drop_connection(int startups) | |
792 | { | |
34fee935 | 793 | int p, r; |
3c0ef626 | 794 | |
795 | if (startups < options.max_startups_begin) | |
796 | return 0; | |
797 | if (startups >= options.max_startups) | |
798 | return 1; | |
799 | if (options.max_startups_rate == 100) | |
800 | return 1; | |
801 | ||
802 | p = 100 - options.max_startups_rate; | |
803 | p *= startups - options.max_startups_begin; | |
34fee935 | 804 | p /= options.max_startups - options.max_startups_begin; |
3c0ef626 | 805 | p += options.max_startups_rate; |
6f25cbdd | 806 | r = arc4random_uniform(100); |
3c0ef626 | 807 | |
34fee935 | 808 | debug("drop_connection: p %d, r %d", p, r); |
3c0ef626 | 809 | return (r < p) ? 1 : 0; |
810 | } | |
811 | ||
1e608e42 | 812 | static void |
813 | usage(void) | |
814 | { | |
2a304a95 | 815 | fprintf(stderr, "%s, %s\n", |
34fee935 | 816 | SSH_RELEASE, SSLeay_version(SSLEAY_VERSION)); |
2a304a95 | 817 | fprintf(stderr, |
6f25cbdd | 818 | "usage: sshd [-46DdeiqTt] [-b bits] [-C connection_spec] [-f config_file]\n" |
819 | " [-g login_grace_time] [-h host_key_file] [-k key_gen_time]\n" | |
820 | " [-o option] [-p port] [-u len]\n" | |
2a304a95 | 821 | ); |
1e608e42 | 822 | exit(1); |
823 | } | |
3c0ef626 | 824 | |
1b56ff3d | 825 | static void |
826 | send_rexec_state(int fd, Buffer *conf) | |
827 | { | |
828 | Buffer m; | |
829 | ||
830 | debug3("%s: entering fd = %d config len %d", __func__, fd, | |
831 | buffer_len(conf)); | |
832 | ||
833 | /* | |
834 | * Protocol from reexec master to child: | |
835 | * string configuration | |
836 | * u_int ephemeral_key_follows | |
837 | * bignum e (only if ephemeral_key_follows == 1) | |
838 | * bignum n " | |
839 | * bignum d " | |
840 | * bignum iqmp " | |
841 | * bignum p " | |
842 | * bignum q " | |
e00da40d | 843 | * string rngseed (only if OpenSSL is not self-seeded) |
1b56ff3d | 844 | */ |
845 | buffer_init(&m); | |
846 | buffer_put_cstring(&m, buffer_ptr(conf)); | |
847 | ||
848 | if (sensitive_data.server_key != NULL && | |
849 | sensitive_data.server_key->type == KEY_RSA1) { | |
850 | buffer_put_int(&m, 1); | |
851 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->e); | |
852 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->n); | |
853 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->d); | |
854 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->iqmp); | |
855 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->p); | |
856 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->q); | |
857 | } else | |
858 | buffer_put_int(&m, 0); | |
859 | ||
e00da40d | 860 | #ifndef OPENSSL_PRNG_ONLY |
861 | rexec_send_rng_seed(&m); | |
862 | #endif | |
863 | ||
1b56ff3d | 864 | if (ssh_msg_send(fd, 0, &m) == -1) |
865 | fatal("%s: ssh_msg_send failed", __func__); | |
866 | ||
867 | buffer_free(&m); | |
868 | ||
869 | debug3("%s: done", __func__); | |
870 | } | |
871 | ||
872 | static void | |
873 | recv_rexec_state(int fd, Buffer *conf) | |
874 | { | |
875 | Buffer m; | |
876 | char *cp; | |
877 | u_int len; | |
878 | ||
879 | debug3("%s: entering fd = %d", __func__, fd); | |
880 | ||
881 | buffer_init(&m); | |
882 | ||
883 | if (ssh_msg_recv(fd, &m) == -1) | |
884 | fatal("%s: ssh_msg_recv failed", __func__); | |
885 | if (buffer_get_char(&m) != 0) | |
886 | fatal("%s: rexec version mismatch", __func__); | |
887 | ||
888 | cp = buffer_get_string(&m, &len); | |
889 | if (conf != NULL) | |
890 | buffer_append(conf, cp, len + 1); | |
891 | xfree(cp); | |
892 | ||
893 | if (buffer_get_int(&m)) { | |
894 | if (sensitive_data.server_key != NULL) | |
895 | key_free(sensitive_data.server_key); | |
896 | sensitive_data.server_key = key_new_private(KEY_RSA1); | |
897 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->e); | |
898 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->n); | |
899 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->d); | |
900 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->iqmp); | |
901 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->p); | |
902 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->q); | |
903 | rsa_generate_additional_parameters( | |
904 | sensitive_data.server_key->rsa); | |
905 | } | |
e00da40d | 906 | |
907 | #ifndef OPENSSL_PRNG_ONLY | |
908 | rexec_recv_rng_seed(&m); | |
909 | #endif | |
910 | ||
1b56ff3d | 911 | buffer_free(&m); |
912 | ||
913 | debug3("%s: done", __func__); | |
914 | } | |
915 | ||
2e437378 | 916 | /* Accept a connection from inetd */ |
917 | static void | |
918 | server_accept_inetd(int *sock_in, int *sock_out) | |
919 | { | |
920 | int fd; | |
921 | ||
922 | startup_pipe = -1; | |
923 | if (rexeced_flag) { | |
924 | close(REEXEC_CONFIG_PASS_FD); | |
925 | *sock_in = *sock_out = dup(STDIN_FILENO); | |
926 | if (!debug_flag) { | |
927 | startup_pipe = dup(REEXEC_STARTUP_PIPE_FD); | |
928 | close(REEXEC_STARTUP_PIPE_FD); | |
929 | } | |
930 | } else { | |
931 | *sock_in = dup(STDIN_FILENO); | |
932 | *sock_out = dup(STDOUT_FILENO); | |
933 | } | |
934 | /* | |
935 | * We intentionally do not close the descriptors 0, 1, and 2 | |
936 | * as our code for setting the descriptors won't work if | |
937 | * ttyfd happens to be one of those. | |
938 | */ | |
939 | if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { | |
940 | dup2(fd, STDIN_FILENO); | |
941 | dup2(fd, STDOUT_FILENO); | |
942 | if (fd > STDOUT_FILENO) | |
943 | close(fd); | |
944 | } | |
945 | debug("inetd sockets after dupping: %d, %d", *sock_in, *sock_out); | |
946 | } | |
947 | ||
948 | /* | |
949 | * Listen for TCP connections | |
950 | */ | |
951 | static void | |
952 | server_listen(void) | |
953 | { | |
954 | int ret, listen_sock, on = 1; | |
955 | struct addrinfo *ai; | |
956 | char ntop[NI_MAXHOST], strport[NI_MAXSERV]; | |
957 | int socksize; | |
958 | int socksizelen = sizeof(int); | |
959 | ||
960 | for (ai = options.listen_addrs; ai; ai = ai->ai_next) { | |
961 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) | |
962 | continue; | |
963 | if (num_listen_socks >= MAX_LISTEN_SOCKS) | |
964 | fatal("Too many listen sockets. " | |
965 | "Enlarge MAX_LISTEN_SOCKS"); | |
966 | if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen, | |
967 | ntop, sizeof(ntop), strport, sizeof(strport), | |
968 | NI_NUMERICHOST|NI_NUMERICSERV)) != 0) { | |
969 | error("getnameinfo failed: %.100s", | |
bd5d5d2a | 970 | ssh_gai_strerror(ret)); |
2e437378 | 971 | continue; |
972 | } | |
973 | /* Create socket for listening. */ | |
974 | listen_sock = socket(ai->ai_family, ai->ai_socktype, | |
975 | ai->ai_protocol); | |
976 | if (listen_sock < 0) { | |
977 | /* kernel may not support ipv6 */ | |
978 | verbose("socket: %.100s", strerror(errno)); | |
979 | continue; | |
980 | } | |
981 | if (set_nonblock(listen_sock) == -1) { | |
982 | close(listen_sock); | |
983 | continue; | |
984 | } | |
985 | /* | |
986 | * Set socket options. | |
987 | * Allow local port reuse in TIME_WAIT. | |
988 | */ | |
989 | if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR, | |
990 | &on, sizeof(on)) == -1) | |
991 | error("setsockopt SO_REUSEADDR: %s", strerror(errno)); | |
992 | ||
bd5d5d2a | 993 | #ifdef IPV6_V6ONLY |
994 | /* Only communicate in IPv6 over AF_INET6 sockets. */ | |
995 | if (ai->ai_family == AF_INET6) { | |
996 | if (setsockopt(listen_sock, IPPROTO_IPV6, IPV6_V6ONLY, | |
997 | &on, sizeof(on)) == -1) | |
998 | error("setsockopt IPV6_V6ONLY: %s", | |
999 | strerror(errno)); | |
1000 | } | |
1001 | #endif | |
1002 | ||
2e437378 | 1003 | debug("Bind to port %s on %s.", strport, ntop); |
bd5d5d2a | 1004 | |
2e437378 | 1005 | getsockopt(listen_sock, SOL_SOCKET, SO_RCVBUF, |
1006 | &socksize, &socksizelen); | |
1007 | debug("Server TCP RWIN socket size: %d", socksize); | |
1008 | debug("HPN Buffer Size: %d", options.hpn_buffer_size); | |
1009 | ||
1010 | /* Bind the socket to the desired port. */ | |
1011 | if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) { | |
1012 | error("Bind to port %s on %s failed: %.200s.", | |
1013 | strport, ntop, strerror(errno)); | |
1014 | close(listen_sock); | |
1015 | continue; | |
1016 | } | |
1017 | listen_socks[num_listen_socks] = listen_sock; | |
1018 | num_listen_socks++; | |
1019 | ||
1020 | /* Start listening on the port. */ | |
1021 | if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0) | |
1022 | fatal("listen on [%s]:%s: %.100s", | |
1023 | ntop, strport, strerror(errno)); | |
1024 | logit("Server listening on %s port %s.", ntop, strport); | |
1025 | } | |
1026 | freeaddrinfo(options.listen_addrs); | |
1027 | ||
1028 | if (!num_listen_socks) | |
1029 | fatal("Cannot bind any address."); | |
1030 | } | |
1031 | ||
1032 | /* | |
1033 | * The main TCP accept loop. Note that, for the non-debug case, returns | |
1034 | * from this function are in a forked subprocess. | |
1035 | */ | |
1036 | static void | |
1037 | server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s) | |
1038 | { | |
1039 | fd_set *fdset; | |
1040 | int i, j, ret, maxfd; | |
1041 | int key_used = 0, startups = 0; | |
1042 | int startup_p[2] = { -1 , -1 }; | |
1043 | struct sockaddr_storage from; | |
1044 | socklen_t fromlen; | |
1045 | pid_t pid; | |
1046 | ||
1047 | /* setup fd set for accept */ | |
1048 | fdset = NULL; | |
1049 | maxfd = 0; | |
1050 | for (i = 0; i < num_listen_socks; i++) | |
1051 | if (listen_socks[i] > maxfd) | |
1052 | maxfd = listen_socks[i]; | |
1053 | /* pipes connected to unauthenticated childs */ | |
1054 | startup_pipes = xcalloc(options.max_startups, sizeof(int)); | |
1055 | for (i = 0; i < options.max_startups; i++) | |
1056 | startup_pipes[i] = -1; | |
1057 | ||
1058 | /* | |
1059 | * Stay listening for connections until the system crashes or | |
1060 | * the daemon is killed with a signal. | |
1061 | */ | |
1062 | for (;;) { | |
1063 | if (received_sighup) | |
1064 | sighup_restart(); | |
1065 | if (fdset != NULL) | |
1066 | xfree(fdset); | |
1067 | fdset = (fd_set *)xcalloc(howmany(maxfd + 1, NFDBITS), | |
1068 | sizeof(fd_mask)); | |
1069 | ||
1070 | for (i = 0; i < num_listen_socks; i++) | |
1071 | FD_SET(listen_socks[i], fdset); | |
1072 | for (i = 0; i < options.max_startups; i++) | |
1073 | if (startup_pipes[i] != -1) | |
1074 | FD_SET(startup_pipes[i], fdset); | |
1075 | ||
1076 | /* Wait in select until there is a connection. */ | |
1077 | ret = select(maxfd+1, fdset, NULL, NULL, NULL); | |
1078 | if (ret < 0 && errno != EINTR) | |
1079 | error("select: %.100s", strerror(errno)); | |
1080 | if (received_sigterm) { | |
1081 | logit("Received signal %d; terminating.", | |
1082 | (int) received_sigterm); | |
1083 | close_listen_socks(); | |
1084 | unlink(options.pid_file); | |
1085 | exit(255); | |
1086 | } | |
1087 | if (key_used && key_do_regen) { | |
1088 | generate_ephemeral_server_key(); | |
1089 | key_used = 0; | |
1090 | key_do_regen = 0; | |
1091 | } | |
1092 | if (ret < 0) | |
1093 | continue; | |
1094 | ||
1095 | for (i = 0; i < options.max_startups; i++) | |
1096 | if (startup_pipes[i] != -1 && | |
1097 | FD_ISSET(startup_pipes[i], fdset)) { | |
1098 | /* | |
1099 | * the read end of the pipe is ready | |
1100 | * if the child has closed the pipe | |
1101 | * after successful authentication | |
1102 | * or if the child has died | |
1103 | */ | |
1104 | close(startup_pipes[i]); | |
1105 | startup_pipes[i] = -1; | |
1106 | startups--; | |
1107 | } | |
1108 | for (i = 0; i < num_listen_socks; i++) { | |
1109 | if (!FD_ISSET(listen_socks[i], fdset)) | |
1110 | continue; | |
1111 | fromlen = sizeof(from); | |
1112 | *newsock = accept(listen_socks[i], | |
1113 | (struct sockaddr *)&from, &fromlen); | |
1114 | if (*newsock < 0) { | |
6f25cbdd | 1115 | if (errno != EINTR && errno != EAGAIN && |
1116 | errno != EWOULDBLOCK) | |
2e437378 | 1117 | error("accept: %.100s", strerror(errno)); |
1118 | continue; | |
1119 | } | |
1120 | if (unset_nonblock(*newsock) == -1) { | |
1121 | close(*newsock); | |
1122 | continue; | |
1123 | } | |
1124 | if (drop_connection(startups) == 1) { | |
1125 | debug("drop connection #%d", startups); | |
1126 | close(*newsock); | |
1127 | continue; | |
1128 | } | |
1129 | if (pipe(startup_p) == -1) { | |
1130 | close(*newsock); | |
1131 | continue; | |
1132 | } | |
1133 | ||
1134 | if (rexec_flag && socketpair(AF_UNIX, | |
1135 | SOCK_STREAM, 0, config_s) == -1) { | |
1136 | error("reexec socketpair: %s", | |
1137 | strerror(errno)); | |
1138 | close(*newsock); | |
1139 | close(startup_p[0]); | |
1140 | close(startup_p[1]); | |
1141 | continue; | |
1142 | } | |
1143 | ||
1144 | for (j = 0; j < options.max_startups; j++) | |
1145 | if (startup_pipes[j] == -1) { | |
1146 | startup_pipes[j] = startup_p[0]; | |
1147 | if (maxfd < startup_p[0]) | |
1148 | maxfd = startup_p[0]; | |
1149 | startups++; | |
1150 | break; | |
1151 | } | |
1152 | ||
1153 | /* | |
1154 | * Got connection. Fork a child to handle it, unless | |
1155 | * we are in debugging mode. | |
1156 | */ | |
1157 | if (debug_flag) { | |
1158 | /* | |
1159 | * In debugging mode. Close the listening | |
1160 | * socket, and start processing the | |
1161 | * connection without forking. | |
1162 | */ | |
1163 | debug("Server will not fork when running in debugging mode."); | |
1164 | close_listen_socks(); | |
1165 | *sock_in = *newsock; | |
1166 | *sock_out = *newsock; | |
1167 | close(startup_p[0]); | |
1168 | close(startup_p[1]); | |
1169 | startup_pipe = -1; | |
1170 | pid = getpid(); | |
1171 | if (rexec_flag) { | |
1172 | send_rexec_state(config_s[0], | |
1173 | &cfg); | |
1174 | close(config_s[0]); | |
1175 | } | |
1176 | break; | |
1177 | } | |
1178 | ||
1179 | /* | |
1180 | * Normal production daemon. Fork, and have | |
1181 | * the child process the connection. The | |
1182 | * parent continues listening. | |
1183 | */ | |
1184 | platform_pre_fork(); | |
1185 | if ((pid = fork()) == 0) { | |
1186 | /* | |
1187 | * Child. Close the listening and | |
1188 | * max_startup sockets. Start using | |
1189 | * the accepted socket. Reinitialize | |
1190 | * logging (since our pid has changed). | |
1191 | * We break out of the loop to handle | |
1192 | * the connection. | |
1193 | */ | |
1194 | platform_post_fork_child(); | |
1195 | startup_pipe = startup_p[1]; | |
1196 | close_startup_pipes(); | |
1197 | close_listen_socks(); | |
1198 | *sock_in = *newsock; | |
1199 | *sock_out = *newsock; | |
1200 | log_init(__progname, | |
1201 | options.log_level, | |
1202 | options.log_facility, | |
1203 | log_stderr); | |
1204 | if (rexec_flag) | |
1205 | close(config_s[0]); | |
1206 | break; | |
1207 | } | |
1208 | ||
1209 | /* Parent. Stay in the loop. */ | |
1210 | platform_post_fork_parent(pid); | |
1211 | if (pid < 0) | |
1212 | error("fork: %.100s", strerror(errno)); | |
1213 | else | |
1214 | debug("Forked child %ld.", (long)pid); | |
1215 | ||
1216 | close(startup_p[1]); | |
1217 | ||
1218 | if (rexec_flag) { | |
1219 | send_rexec_state(config_s[0], &cfg); | |
1220 | close(config_s[0]); | |
1221 | close(config_s[1]); | |
1222 | } | |
1223 | ||
1224 | /* | |
1225 | * Mark that the key has been used (it | |
1226 | * was "given" to the child). | |
1227 | */ | |
1228 | if ((options.protocol & SSH_PROTO_1) && | |
1229 | key_used == 0) { | |
1230 | /* Schedule server key regeneration alarm. */ | |
1231 | signal(SIGALRM, key_regeneration_alarm); | |
1232 | alarm(options.key_regeneration_time); | |
1233 | key_used = 1; | |
1234 | } | |
1235 | ||
1236 | close(*newsock); | |
1237 | ||
1238 | /* | |
1239 | * Ensure that our random state differs | |
1240 | * from that of the child | |
1241 | */ | |
1242 | arc4random_stir(); | |
1243 | } | |
1244 | ||
1245 | /* child process check (or debug mode) */ | |
1246 | if (num_listen_socks < 0) | |
1247 | break; | |
1248 | } | |
1249 | } | |
1250 | ||
1251 | ||
3c0ef626 | 1252 | /* |
1253 | * Main program for the daemon. | |
1254 | */ | |
1255 | int | |
1256 | main(int ac, char **av) | |
1257 | { | |
1258 | extern char *optarg; | |
1259 | extern int optind; | |
2e437378 | 1260 | int opt, i, on = 1; |
1b56ff3d | 1261 | int sock_in = -1, sock_out = -1, newsock = -1; |
3c0ef626 | 1262 | const char *remote_ip; |
6f25cbdd | 1263 | char *test_user = NULL, *test_host = NULL, *test_addr = NULL; |
3c0ef626 | 1264 | int remote_port; |
6f25cbdd | 1265 | char *line, *p, *cp; |
2e437378 | 1266 | int config_s[2] = { -1 , -1 }; |
6f25cbdd | 1267 | u_int64_t ibytes, obytes; |
1268 | mode_t new_umask; | |
3c0ef626 | 1269 | Key *key; |
416fd2a8 | 1270 | Authctxt *authctxt; |
3c0ef626 | 1271 | |
2980ea68 | 1272 | #ifdef HAVE_SECUREWARE |
1273 | (void)set_auth_parameters(ac, av); | |
1274 | #endif | |
70791e56 | 1275 | __progname = ssh_get_progname(av[0]); |
ae43c103 | 1276 | init_pathnames(); |
004706ea | 1277 | config_file_name = _PATH_SERVER_CONFIG_FILE; |
3c0ef626 | 1278 | init_rng(); |
1279 | ||
1c14df9e | 1280 | /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */ |
3c0ef626 | 1281 | saved_argc = ac; |
1b56ff3d | 1282 | rexec_argc = ac; |
2e437378 | 1283 | saved_argv = xcalloc(ac + 1, sizeof(*saved_argv)); |
1c14df9e | 1284 | for (i = 0; i < ac; i++) |
1285 | saved_argv[i] = xstrdup(av[i]); | |
70791e56 | 1286 | saved_argv[i] = NULL; |
1c14df9e | 1287 | |
1288 | #ifndef HAVE_SETPROCTITLE | |
1289 | /* Prepare for later setproctitle emulation */ | |
1290 | compat_init_setproctitle(ac, av); | |
70791e56 | 1291 | av = saved_argv; |
1c14df9e | 1292 | #endif |
3c0ef626 | 1293 | |
2a304a95 | 1294 | if (geteuid() == 0 && setgroups(0, NULL) == -1) |
1295 | debug("setgroups(): %.200s", strerror(errno)); | |
1296 | ||
e00da40d | 1297 | /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ |
1298 | sanitise_stdfd(); | |
1299 | ||
3c0ef626 | 1300 | /* Initialize configuration options to their default values. */ |
1301 | initialize_server_options(&options); | |
1302 | ||
1303 | /* Parse command-line arguments. */ | |
6f25cbdd | 1304 | while ((opt = getopt(ac, av, "f:p:b:k:h:g:u:o:C:dDeiqrtQRT46")) != -1) { |
3c0ef626 | 1305 | switch (opt) { |
1306 | case '4': | |
34fee935 | 1307 | options.address_family = AF_INET; |
3c0ef626 | 1308 | break; |
1309 | case '6': | |
34fee935 | 1310 | options.address_family = AF_INET6; |
3c0ef626 | 1311 | break; |
1312 | case 'f': | |
1313 | config_file_name = optarg; | |
1314 | break; | |
1315 | case 'd': | |
70791e56 | 1316 | if (debug_flag == 0) { |
3c0ef626 | 1317 | debug_flag = 1; |
1318 | options.log_level = SYSLOG_LEVEL_DEBUG1; | |
70791e56 | 1319 | } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) |
3c0ef626 | 1320 | options.log_level++; |
3c0ef626 | 1321 | break; |
1322 | case 'D': | |
1323 | no_daemon_flag = 1; | |
1324 | break; | |
1325 | case 'e': | |
1326 | log_stderr = 1; | |
1327 | break; | |
1328 | case 'i': | |
1329 | inetd_flag = 1; | |
1330 | break; | |
1b56ff3d | 1331 | case 'r': |
1332 | rexec_flag = 0; | |
1333 | break; | |
1334 | case 'R': | |
1335 | rexeced_flag = 1; | |
1336 | inetd_flag = 1; | |
1337 | break; | |
3c0ef626 | 1338 | case 'Q': |
1339 | /* ignored */ | |
1340 | break; | |
1341 | case 'q': | |
1342 | options.log_level = SYSLOG_LEVEL_QUIET; | |
1343 | break; | |
1344 | case 'b': | |
2e437378 | 1345 | options.server_key_bits = (int)strtonum(optarg, 256, |
1346 | 32768, NULL); | |
3c0ef626 | 1347 | break; |
1348 | case 'p': | |
1349 | options.ports_from_cmdline = 1; | |
1350 | if (options.num_ports >= MAX_PORTS) { | |
1351 | fprintf(stderr, "too many ports.\n"); | |
1352 | exit(1); | |
1353 | } | |
1354 | options.ports[options.num_ports++] = a2port(optarg); | |
16eb0a3b | 1355 | if (options.ports[options.num_ports-1] <= 0) { |
3c0ef626 | 1356 | fprintf(stderr, "Bad port number.\n"); |
1357 | exit(1); | |
1358 | } | |
1359 | break; | |
1360 | case 'g': | |
1361 | if ((options.login_grace_time = convtime(optarg)) == -1) { | |
1362 | fprintf(stderr, "Invalid login grace time.\n"); | |
1363 | exit(1); | |
1364 | } | |
1365 | break; | |
1366 | case 'k': | |
1367 | if ((options.key_regeneration_time = convtime(optarg)) == -1) { | |
1368 | fprintf(stderr, "Invalid key regeneration interval.\n"); | |
1369 | exit(1); | |
1370 | } | |
1371 | break; | |
1372 | case 'h': | |
1373 | if (options.num_host_key_files >= MAX_HOSTKEYS) { | |
1374 | fprintf(stderr, "too many host keys.\n"); | |
1375 | exit(1); | |
1376 | } | |
1377 | options.host_key_files[options.num_host_key_files++] = optarg; | |
1378 | break; | |
3c0ef626 | 1379 | case 't': |
1380 | test_flag = 1; | |
1381 | break; | |
6f25cbdd | 1382 | case 'T': |
1383 | test_flag = 2; | |
1384 | break; | |
1385 | case 'C': | |
1386 | cp = optarg; | |
1387 | while ((p = strsep(&cp, ",")) && *p != '\0') { | |
1388 | if (strncmp(p, "addr=", 5) == 0) | |
1389 | test_addr = xstrdup(p + 5); | |
1390 | else if (strncmp(p, "host=", 5) == 0) | |
1391 | test_host = xstrdup(p + 5); | |
1392 | else if (strncmp(p, "user=", 5) == 0) | |
1393 | test_user = xstrdup(p + 5); | |
1394 | else { | |
1395 | fprintf(stderr, "Invalid test " | |
1396 | "mode specification %s\n", p); | |
1397 | exit(1); | |
1398 | } | |
1399 | } | |
1400 | break; | |
3c0ef626 | 1401 | case 'u': |
2e437378 | 1402 | utmp_len = (u_int)strtonum(optarg, 0, MAXHOSTNAMELEN+1, NULL); |
e54b3d7c | 1403 | if (utmp_len > MAXHOSTNAMELEN) { |
1404 | fprintf(stderr, "Invalid utmp length.\n"); | |
1405 | exit(1); | |
1406 | } | |
3c0ef626 | 1407 | break; |
1e608e42 | 1408 | case 'o': |
416fd2a8 | 1409 | line = xstrdup(optarg); |
1410 | if (process_server_config_line(&options, line, | |
2e437378 | 1411 | "command-line", 0, NULL, NULL, NULL, NULL) != 0) |
1e608e42 | 1412 | exit(1); |
416fd2a8 | 1413 | xfree(line); |
1e608e42 | 1414 | break; |
3c0ef626 | 1415 | case '?': |
1416 | default: | |
1e608e42 | 1417 | usage(); |
1418 | break; | |
3c0ef626 | 1419 | } |
1420 | } | |
1b56ff3d | 1421 | if (rexeced_flag || inetd_flag) |
1422 | rexec_flag = 0; | |
bd5d5d2a | 1423 | if (!test_flag && (rexec_flag && (av[0] == NULL || *av[0] != '/'))) |
1b56ff3d | 1424 | fatal("sshd re-exec requires execution with an absolute path"); |
1425 | if (rexeced_flag) | |
1426 | closefrom(REEXEC_MIN_FREE_FD); | |
1427 | else | |
1428 | closefrom(REEXEC_DEVCRYPTO_RESERVED_FD); | |
1429 | ||
3c0ef626 | 1430 | SSLeay_add_all_algorithms(); |
3c0ef626 | 1431 | |
1432 | /* | |
1433 | * Force logging to stderr until we have loaded the private host | |
1434 | * key (unless started from inetd) | |
1435 | */ | |
1436 | log_init(__progname, | |
1e608e42 | 1437 | options.log_level == SYSLOG_LEVEL_NOT_SET ? |
1438 | SYSLOG_LEVEL_INFO : options.log_level, | |
1439 | options.log_facility == SYSLOG_FACILITY_NOT_SET ? | |
1440 | SYSLOG_FACILITY_AUTH : options.log_facility, | |
1c14df9e | 1441 | log_stderr || !inetd_flag); |
3c0ef626 | 1442 | |
2a304a95 | 1443 | /* |
1444 | * Unset KRB5CCNAME, otherwise the user's session may inherit it from | |
1445 | * root's environment | |
34fee935 | 1446 | */ |
1447 | if (getenv("KRB5CCNAME") != NULL) | |
1448 | unsetenv("KRB5CCNAME"); | |
1449 | ||
e54b3d7c | 1450 | #ifdef _UNICOS |
1b56ff3d | 1451 | /* Cray can define user privs drop all privs now! |
3c0ef626 | 1452 | * Not needed on PRIV_SU systems! |
1453 | */ | |
1454 | drop_cray_privs(); | |
1455 | #endif | |
1456 | ||
1b56ff3d | 1457 | sensitive_data.server_key = NULL; |
1458 | sensitive_data.ssh1_host_key = NULL; | |
1459 | sensitive_data.have_ssh1_key = 0; | |
1460 | sensitive_data.have_ssh2_key = 0; | |
1461 | ||
6f25cbdd | 1462 | /* |
1463 | * If we're doing an extended config test, make sure we have all of | |
1464 | * the parameters we need. If we're not doing an extended test, | |
1465 | * do not silently ignore connection test params. | |
1466 | */ | |
1467 | if (test_flag >= 2 && | |
1468 | (test_user != NULL || test_host != NULL || test_addr != NULL) | |
1469 | && (test_user == NULL || test_host == NULL || test_addr == NULL)) | |
1470 | fatal("user, host and addr are all required when testing " | |
1471 | "Match configs"); | |
1472 | if (test_flag < 2 && (test_user != NULL || test_host != NULL || | |
1473 | test_addr != NULL)) | |
1474 | fatal("Config test connection parameter (-C) provided without " | |
1475 | "test mode (-T)"); | |
1476 | ||
1b56ff3d | 1477 | /* Fetch our configuration */ |
1478 | buffer_init(&cfg); | |
1479 | if (rexeced_flag) | |
1480 | recv_rexec_state(REEXEC_CONFIG_PASS_FD, &cfg); | |
1481 | else | |
1482 | load_server_config(config_file_name, &cfg); | |
1483 | ||
2e437378 | 1484 | parse_server_config(&options, rexeced_flag ? "rexec" : config_file_name, |
1485 | &cfg, NULL, NULL, NULL); | |
3c0ef626 | 1486 | |
e00da40d | 1487 | seed_rng(); |
1488 | ||
3c0ef626 | 1489 | /* Fill in default values for those options not explicitly set. */ |
1490 | fill_default_server_options(&options); | |
1491 | ||
25d429a2 | 1492 | /* challenge-response is implemented via keyboard interactive */ |
1493 | if (options.challenge_response_authentication) | |
1494 | options.kbd_interactive_authentication = 1; | |
1495 | ||
34fee935 | 1496 | /* set default channel AF */ |
1497 | channel_set_af(options.address_family); | |
1498 | ||
3c0ef626 | 1499 | /* Check that there are no remaining arguments. */ |
1500 | if (optind < ac) { | |
1501 | fprintf(stderr, "Extra argument %s.\n", av[optind]); | |
1502 | exit(1); | |
1503 | } | |
1504 | ||
34fee935 | 1505 | debug("sshd version %.100s", SSH_RELEASE); |
3c0ef626 | 1506 | |
2e437378 | 1507 | /* Store privilege separation user for later use if required. */ |
1508 | if ((privsep_pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) { | |
1509 | if (use_privsep || options.kerberos_authentication) | |
1510 | fatal("Privilege separation user %s does not exist", | |
1511 | SSH_PRIVSEP_USER); | |
1512 | } else { | |
1513 | memset(privsep_pw->pw_passwd, 0, strlen(privsep_pw->pw_passwd)); | |
1514 | privsep_pw = pwcopy(privsep_pw); | |
1515 | xfree(privsep_pw->pw_passwd); | |
1516 | privsep_pw->pw_passwd = xstrdup("*"); | |
1517 | } | |
1518 | endpwent(); | |
1519 | ||
3c0ef626 | 1520 | /* load private host keys */ |
2e437378 | 1521 | sensitive_data.host_keys = xcalloc(options.num_host_key_files, |
e54b3d7c | 1522 | sizeof(Key *)); |
1e608e42 | 1523 | for (i = 0; i < options.num_host_key_files; i++) |
3c0ef626 | 1524 | sensitive_data.host_keys[i] = NULL; |
3c0ef626 | 1525 | |
1e608e42 | 1526 | for (i = 0; i < options.num_host_key_files; i++) { |
3c0ef626 | 1527 | key = key_load_private(options.host_key_files[i], "", NULL); |
1528 | sensitive_data.host_keys[i] = key; | |
1529 | if (key == NULL) { | |
1530 | error("Could not load host key: %s", | |
1531 | options.host_key_files[i]); | |
1532 | sensitive_data.host_keys[i] = NULL; | |
1533 | continue; | |
1534 | } | |
1e608e42 | 1535 | switch (key->type) { |
3c0ef626 | 1536 | case KEY_RSA1: |
1537 | sensitive_data.ssh1_host_key = key; | |
1538 | sensitive_data.have_ssh1_key = 1; | |
1539 | break; | |
1540 | case KEY_RSA: | |
1541 | case KEY_DSA: | |
1542 | sensitive_data.have_ssh2_key = 1; | |
1543 | break; | |
1544 | } | |
1545 | debug("private host key: #%d type %d %s", i, key->type, | |
1546 | key_type(key)); | |
1547 | } | |
1548 | if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) { | |
70791e56 | 1549 | logit("Disabling protocol version 1. Could not load host key"); |
3c0ef626 | 1550 | options.protocol &= ~SSH_PROTO_1; |
1551 | } | |
5598e598 | 1552 | #ifndef GSSAPI |
1553 | /* The GSSAPI key exchange can run without a host key */ | |
3c0ef626 | 1554 | if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) { |
70791e56 | 1555 | logit("Disabling protocol version 2. Could not load host key"); |
3c0ef626 | 1556 | options.protocol &= ~SSH_PROTO_2; |
1557 | } | |
5598e598 | 1558 | #endif |
3c0ef626 | 1559 | if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) { |
70791e56 | 1560 | logit("sshd: no hostkeys available -- exiting."); |
3c0ef626 | 1561 | exit(1); |
1562 | } | |
1563 | ||
1564 | /* Check certain values for sanity. */ | |
1565 | if (options.protocol & SSH_PROTO_1) { | |
1566 | if (options.server_key_bits < 512 || | |
1567 | options.server_key_bits > 32768) { | |
1568 | fprintf(stderr, "Bad server key size.\n"); | |
1569 | exit(1); | |
1570 | } | |
1571 | /* | |
1572 | * Check that server and host key lengths differ sufficiently. This | |
1573 | * is necessary to make double encryption work with rsaref. Oh, I | |
1574 | * hate software patents. I dont know if this can go? Niels | |
1575 | */ | |
1576 | if (options.server_key_bits > | |
ff2d7a98 | 1577 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) - |
1578 | SSH_KEY_BITS_RESERVED && options.server_key_bits < | |
1579 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + | |
1580 | SSH_KEY_BITS_RESERVED) { | |
3c0ef626 | 1581 | options.server_key_bits = |
ff2d7a98 | 1582 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + |
1583 | SSH_KEY_BITS_RESERVED; | |
3c0ef626 | 1584 | debug("Forcing server key to %d bits to make it differ from host key.", |
1585 | options.server_key_bits); | |
1586 | } | |
1587 | } | |
1588 | ||
ff2d7a98 | 1589 | if (use_privsep) { |
ff2d7a98 | 1590 | struct stat st; |
1591 | ||
ff2d7a98 | 1592 | if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) || |
1593 | (S_ISDIR(st.st_mode) == 0)) | |
1594 | fatal("Missing privilege separation directory: %s", | |
1595 | _PATH_PRIVSEP_CHROOT_DIR); | |
e54b3d7c | 1596 | |
1597 | #ifdef HAVE_CYGWIN | |
1598 | if (check_ntsec(_PATH_PRIVSEP_CHROOT_DIR) && | |
1599 | (st.st_uid != getuid () || | |
1600 | (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)) | |
1601 | #else | |
ff2d7a98 | 1602 | if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0) |
e54b3d7c | 1603 | #endif |
1c14df9e | 1604 | fatal("%s must be owned by root and not group or " |
1605 | "world-writable.", _PATH_PRIVSEP_CHROOT_DIR); | |
ff2d7a98 | 1606 | } |
1607 | ||
6f25cbdd | 1608 | if (test_flag > 1) { |
1609 | if (test_user != NULL && test_addr != NULL && test_host != NULL) | |
1610 | parse_server_match_config(&options, test_user, | |
1611 | test_host, test_addr); | |
1612 | dump_config(&options); | |
1613 | } | |
1614 | ||
3c0ef626 | 1615 | /* Configuration looks good, so exit if in test mode. */ |
1616 | if (test_flag) | |
1617 | exit(0); | |
1618 | ||
2980ea68 | 1619 | /* |
1620 | * Clear out any supplemental groups we may have inherited. This | |
1621 | * prevents inadvertent creation of files with bad modes (in the | |
416fd2a8 | 1622 | * portable version at least, it's certainly possible for PAM |
1623 | * to create a file, and we can't control the code in every | |
2980ea68 | 1624 | * module which might be used). |
1625 | */ | |
1626 | if (setgroups(0, NULL) < 0) | |
1627 | debug("setgroups() failed: %.200s", strerror(errno)); | |
3c0ef626 | 1628 | |
1b56ff3d | 1629 | if (rexec_flag) { |
2e437378 | 1630 | rexec_argv = xcalloc(rexec_argc + 2, sizeof(char *)); |
1b56ff3d | 1631 | for (i = 0; i < rexec_argc; i++) { |
1632 | debug("rexec_argv[%d]='%s'", i, saved_argv[i]); | |
1633 | rexec_argv[i] = saved_argv[i]; | |
1634 | } | |
1635 | rexec_argv[rexec_argc] = "-R"; | |
1636 | rexec_argv[rexec_argc + 1] = NULL; | |
1637 | } | |
1638 | ||
6f25cbdd | 1639 | /* Ensure that umask disallows at least group and world write */ |
1640 | new_umask = umask(0077) | 0022; | |
1641 | (void) umask(new_umask); | |
1642 | ||
3c0ef626 | 1643 | /* Initialize the log (it is reinitialized below in case we forked). */ |
34fee935 | 1644 | if (debug_flag && (!inetd_flag || rexeced_flag)) |
3c0ef626 | 1645 | log_stderr = 1; |
1646 | log_init(__progname, options.log_level, options.log_facility, log_stderr); | |
1647 | ||
1648 | /* | |
1649 | * If not in debugging mode, and not started from inetd, disconnect | |
1650 | * from the controlling terminal, and fork. The original process | |
1651 | * exits. | |
1652 | */ | |
1653 | if (!(debug_flag || inetd_flag || no_daemon_flag)) { | |
1654 | #ifdef TIOCNOTTY | |
1655 | int fd; | |
1656 | #endif /* TIOCNOTTY */ | |
1657 | if (daemon(0, 0) < 0) | |
1658 | fatal("daemon() failed: %.200s", strerror(errno)); | |
1659 | ||
1660 | /* Disconnect from the controlling tty. */ | |
1661 | #ifdef TIOCNOTTY | |
1662 | fd = open(_PATH_TTY, O_RDWR | O_NOCTTY); | |
1663 | if (fd >= 0) { | |
1664 | (void) ioctl(fd, TIOCNOTTY, NULL); | |
1665 | close(fd); | |
1666 | } | |
1667 | #endif /* TIOCNOTTY */ | |
1668 | } | |
1669 | /* Reinitialize the log (because of the fork above). */ | |
1670 | log_init(__progname, options.log_level, options.log_facility, log_stderr); | |
1671 | ||
1672 | /* Initialize the random number generator. */ | |
1673 | arc4random_stir(); | |
1674 | ||
1675 | /* Chdir to the root directory so that the current disk can be | |
1676 | unmounted if desired. */ | |
1677 | chdir("/"); | |
1e608e42 | 1678 | |
3c0ef626 | 1679 | /* ignore SIGPIPE */ |
1680 | signal(SIGPIPE, SIG_IGN); | |
1681 | ||
2e437378 | 1682 | /* Get a connection, either from inetd or a listening TCP socket */ |
3c0ef626 | 1683 | if (inetd_flag) { |
2e437378 | 1684 | server_accept_inetd(&sock_in, &sock_out); |
3c0ef626 | 1685 | } else { |
2e437378 | 1686 | server_listen(); |
3c0ef626 | 1687 | |
1688 | if (options.protocol & SSH_PROTO_1) | |
1689 | generate_ephemeral_server_key(); | |
1690 | ||
3c0ef626 | 1691 | signal(SIGHUP, sighup_handler); |
2e437378 | 1692 | signal(SIGCHLD, main_sigchld_handler); |
3c0ef626 | 1693 | signal(SIGTERM, sigterm_handler); |
1694 | signal(SIGQUIT, sigterm_handler); | |
1695 | ||
2e437378 | 1696 | /* |
1697 | * Write out the pid file after the sigterm handler | |
1698 | * is setup and the listen sockets are bound | |
1699 | */ | |
3c0ef626 | 1700 | if (!debug_flag) { |
2e437378 | 1701 | FILE *f = fopen(options.pid_file, "w"); |
1702 | ||
70791e56 | 1703 | if (f == NULL) { |
1704 | error("Couldn't create pid file \"%s\": %s", | |
1705 | options.pid_file, strerror(errno)); | |
1706 | } else { | |
ff2d7a98 | 1707 | fprintf(f, "%ld\n", (long) getpid()); |
3c0ef626 | 1708 | fclose(f); |
1709 | } | |
1710 | } | |
1711 | ||
2e437378 | 1712 | /* Accept a connection and return in a forked child */ |
1713 | server_accept_loop(&sock_in, &sock_out, | |
1714 | &newsock, config_s); | |
3c0ef626 | 1715 | } |
1716 | ||
1717 | /* This is the child processing a new connection. */ | |
2a304a95 | 1718 | setproctitle("%s", "[accepted]"); |
3c0ef626 | 1719 | |
2980ea68 | 1720 | /* |
1721 | * Create a new session and process group since the 4.4BSD | |
1722 | * setlogin() affects the entire process group. We don't | |
1723 | * want the child to be able to affect the parent. | |
1724 | */ | |
70791e56 | 1725 | #if !defined(SSHD_ACQUIRES_CTTY) |
1c14df9e | 1726 | /* |
70791e56 | 1727 | * If setsid is called, on some platforms sshd will later acquire a |
1728 | * controlling terminal which will result in "could not set | |
1729 | * controlling tty" errors. | |
1c14df9e | 1730 | */ |
ff2d7a98 | 1731 | if (!debug_flag && !inetd_flag && setsid() < 0) |
2980ea68 | 1732 | error("setsid: %.100s", strerror(errno)); |
1733 | #endif | |
1734 | ||
1b56ff3d | 1735 | if (rexec_flag) { |
1736 | int fd; | |
1737 | ||
1738 | debug("rexec start in %d out %d newsock %d pipe %d sock %d", | |
1739 | sock_in, sock_out, newsock, startup_pipe, config_s[0]); | |
1740 | dup2(newsock, STDIN_FILENO); | |
1741 | dup2(STDIN_FILENO, STDOUT_FILENO); | |
1742 | if (startup_pipe == -1) | |
1743 | close(REEXEC_STARTUP_PIPE_FD); | |
1744 | else | |
1745 | dup2(startup_pipe, REEXEC_STARTUP_PIPE_FD); | |
1746 | ||
1747 | dup2(config_s[1], REEXEC_CONFIG_PASS_FD); | |
1748 | close(config_s[1]); | |
1749 | if (startup_pipe != -1) | |
1750 | close(startup_pipe); | |
1751 | ||
1752 | execv(rexec_argv[0], rexec_argv); | |
1753 | ||
1754 | /* Reexec has failed, fall back and continue */ | |
1755 | error("rexec of %s failed: %s", rexec_argv[0], strerror(errno)); | |
1756 | recv_rexec_state(REEXEC_CONFIG_PASS_FD, NULL); | |
1757 | log_init(__progname, options.log_level, | |
1758 | options.log_facility, log_stderr); | |
1759 | ||
1760 | /* Clean up fds */ | |
1761 | startup_pipe = REEXEC_STARTUP_PIPE_FD; | |
1762 | close(config_s[1]); | |
1763 | close(REEXEC_CONFIG_PASS_FD); | |
1764 | newsock = sock_out = sock_in = dup(STDIN_FILENO); | |
1765 | if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { | |
1766 | dup2(fd, STDIN_FILENO); | |
1767 | dup2(fd, STDOUT_FILENO); | |
1768 | if (fd > STDERR_FILENO) | |
1769 | close(fd); | |
1770 | } | |
1771 | debug("rexec cleanup in %d out %d newsock %d pipe %d sock %d", | |
1772 | sock_in, sock_out, newsock, startup_pipe, config_s[0]); | |
1773 | } | |
1774 | ||
3c0ef626 | 1775 | /* |
1776 | * Disable the key regeneration alarm. We will not regenerate the | |
1777 | * key since we are no longer in a position to give it to anyone. We | |
1778 | * will not restart on SIGHUP since it no longer makes sense. | |
1779 | */ | |
1780 | alarm(0); | |
1781 | signal(SIGALRM, SIG_DFL); | |
1782 | signal(SIGHUP, SIG_DFL); | |
1783 | signal(SIGTERM, SIG_DFL); | |
1784 | signal(SIGQUIT, SIG_DFL); | |
1785 | signal(SIGCHLD, SIG_DFL); | |
1786 | signal(SIGINT, SIG_DFL); | |
1787 | ||
3c0ef626 | 1788 | /* |
1789 | * Register our connection. This turns encryption off because we do | |
1790 | * not have a key. | |
1791 | */ | |
1792 | packet_set_connection(sock_in, sock_out); | |
34fee935 | 1793 | packet_set_server(); |
1794 | ||
1795 | /* Set SO_KEEPALIVE if requested. */ | |
1796 | if (options.tcp_keep_alive && packet_connection_is_on_socket() && | |
1797 | setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) < 0) | |
1798 | error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); | |
3c0ef626 | 1799 | |
34fee935 | 1800 | if ((remote_port = get_remote_port()) < 0) { |
1801 | debug("get_remote_port failed"); | |
1802 | cleanup_exit(255); | |
1803 | } | |
e00da40d | 1804 | |
46201ce0 | 1805 | /* set the HPN options for the child */ |
1806 | channel_set_hpn(options.hpn_disabled, options.hpn_buffer_size); | |
1807 | ||
e00da40d | 1808 | /* |
1809 | * We use get_canonical_hostname with usedns = 0 instead of | |
1810 | * get_remote_ipaddr here so IP options will be checked. | |
1811 | */ | |
2e437378 | 1812 | (void) get_canonical_hostname(0); |
1813 | /* | |
1814 | * The rest of the code depends on the fact that | |
1815 | * get_remote_ipaddr() caches the remote ip, even if | |
1816 | * the socket goes away. | |
1817 | */ | |
1818 | remote_ip = get_remote_ipaddr(); | |
3c0ef626 | 1819 | |
34fee935 | 1820 | #ifdef SSH_AUDIT_EVENTS |
1821 | audit_connection_from(remote_ip, remote_port); | |
1822 | #endif | |
3c0ef626 | 1823 | #ifdef LIBWRAP |
bd5d5d2a | 1824 | allow_severity = options.log_facility|LOG_INFO; |
1825 | deny_severity = options.log_facility|LOG_WARNING; | |
3c0ef626 | 1826 | /* Check whether logins are denied from this host. */ |
1b56ff3d | 1827 | if (packet_connection_is_on_socket()) { |
3c0ef626 | 1828 | struct request_info req; |
1829 | ||
1830 | request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0); | |
1831 | fromhost(&req); | |
1832 | ||
1833 | if (!hosts_access(&req)) { | |
1834 | debug("Connection refused by tcp wrapper"); | |
1835 | refuse(&req); | |
1836 | /* NOTREACHED */ | |
1837 | fatal("libwrap refuse returns"); | |
1838 | } | |
1839 | } | |
1840 | #endif /* LIBWRAP */ | |
1841 | ||
1842 | /* Log the connection. */ | |
1843 | verbose("Connection from %.500s port %d", remote_ip, remote_port); | |
1844 | ||
34fee935 | 1845 | #ifdef USE_SECURITY_SESSION_API |
1846 | /* | |
1847 | * Create a new security session for use by the new user login if | |
1848 | * the current session is the root session or we are not launched | |
1849 | * by inetd (eg: debugging mode or server mode). We do not | |
1850 | * necessarily need to create a session if we are launched from | |
1851 | * inetd because Panther xinetd will create a session for us. | |
1852 | * | |
1853 | * The only case where this logic will fail is if there is an | |
1854 | * inetd running in a non-root session which is not creating | |
1855 | * new sessions for us. Then all the users will end up in the | |
1856 | * same session (bad). | |
1857 | * | |
1858 | * When the client exits, the session will be destroyed for us | |
1859 | * automatically. | |
1860 | * | |
1861 | * We must create the session before any credentials are stored | |
1862 | * (including AFS pags, which happens a few lines below). | |
1863 | */ | |
1864 | { | |
1865 | OSStatus err = 0; | |
1866 | SecuritySessionId sid = 0; | |
1867 | SessionAttributeBits sattrs = 0; | |
1868 | ||
1869 | err = SessionGetInfo(callerSecuritySession, &sid, &sattrs); | |
1870 | if (err) | |
1871 | error("SessionGetInfo() failed with error %.8X", | |
1872 | (unsigned) err); | |
1873 | else | |
1874 | debug("Current Session ID is %.8X / Session Attributes are %.8X", | |
1875 | (unsigned) sid, (unsigned) sattrs); | |
1876 | ||
1877 | if (inetd_flag && !(sattrs & sessionIsRoot)) | |
1878 | debug("Running in inetd mode in a non-root session... " | |
1879 | "assuming inetd created the session for us."); | |
1880 | else { | |
1881 | debug("Creating new security session..."); | |
1882 | err = SessionCreate(0, sessionHasTTY | sessionIsRemote); | |
1883 | if (err) | |
1884 | error("SessionCreate() failed with error %.8X", | |
1885 | (unsigned) err); | |
1886 | ||
1887 | err = SessionGetInfo(callerSecuritySession, &sid, | |
1888 | &sattrs); | |
1889 | if (err) | |
1890 | error("SessionGetInfo() failed with error %.8X", | |
1891 | (unsigned) err); | |
1892 | else | |
1893 | debug("New Session ID is %.8X / Session Attributes are %.8X", | |
1894 | (unsigned) sid, (unsigned) sattrs); | |
1895 | } | |
1896 | } | |
1897 | #endif | |
1898 | ||
3c0ef626 | 1899 | /* |
e00da40d | 1900 | * We don't want to listen forever unless the other side |
3c0ef626 | 1901 | * successfully authenticates itself. So we set up an alarm which is |
1902 | * cleared after successful authentication. A limit of zero | |
e00da40d | 1903 | * indicates no limit. Note that we don't set the alarm in debugging |
3c0ef626 | 1904 | * mode; it is just annoying to have the server exit just when you |
1905 | * are about to discover the bug. | |
1906 | */ | |
1907 | signal(SIGALRM, grace_alarm_handler); | |
1908 | if (!debug_flag) | |
1909 | alarm(options.login_grace_time); | |
1910 | ||
1911 | sshd_exchange_identification(sock_in, sock_out); | |
70791e56 | 1912 | #if defined(AFS_KRB5) |
3c0ef626 | 1913 | /* If machine has AFS, set process authentication group. */ |
1914 | if (k_hasafs()) { | |
1915 | k_setpag(); | |
1916 | k_unlog(); | |
1917 | } | |
f2fd21a2 | 1918 | #endif /* AFS || AFS_KRB5 */ |
3c0ef626 | 1919 | |
bd5d5d2a | 1920 | /* In inetd mode, generate ephemeral key only for proto 1 connections */ |
1921 | if (!compat20 && inetd_flag && sensitive_data.server_key == NULL) | |
1922 | generate_ephemeral_server_key(); | |
1923 | ||
3c0ef626 | 1924 | packet_set_nonblocking(); |
1925 | ||
416fd2a8 | 1926 | /* allocate authentication context */ |
2e437378 | 1927 | authctxt = xcalloc(1, sizeof(*authctxt)); |
416fd2a8 | 1928 | |
34fee935 | 1929 | authctxt->loginmsg = &loginmsg; |
1930 | ||
416fd2a8 | 1931 | /* XXX global for cleanup, access from other modules */ |
1932 | the_authctxt = authctxt; | |
1933 | ||
34fee935 | 1934 | /* prepare buffer to collect messages to display to user after login */ |
1935 | buffer_init(&loginmsg); | |
1936 | ||
2980ea68 | 1937 | if (use_privsep) |
416fd2a8 | 1938 | if (privsep_preauth(authctxt) == 1) |
2980ea68 | 1939 | goto authenticated; |
1940 | ||
3c0ef626 | 1941 | /* perform the key exchange */ |
1942 | /* authenticate user and start session */ | |
1943 | if (compat20) { | |
1944 | do_ssh2_kex(); | |
416fd2a8 | 1945 | do_authentication2(authctxt); |
3c0ef626 | 1946 | } else { |
1947 | do_ssh1_kex(); | |
416fd2a8 | 1948 | do_authentication(authctxt); |
2980ea68 | 1949 | } |
1950 | /* | |
1951 | * If we use privilege separation, the unprivileged child transfers | |
1952 | * the current keystate and exits | |
1953 | */ | |
1954 | if (use_privsep) { | |
1955 | mm_send_keystate(pmonitor); | |
1956 | exit(0); | |
3c0ef626 | 1957 | } |
2980ea68 | 1958 | |
1959 | authenticated: | |
e00da40d | 1960 | /* |
1961 | * Cancel the alarm we set to limit the time taken for | |
1962 | * authentication. | |
1963 | */ | |
1964 | alarm(0); | |
1965 | signal(SIGALRM, SIG_DFL); | |
2e437378 | 1966 | authctxt->authenticated = 1; |
e00da40d | 1967 | if (startup_pipe != -1) { |
1968 | close(startup_pipe); | |
1969 | startup_pipe = -1; | |
1970 | } | |
1971 | ||
34fee935 | 1972 | #ifdef SSH_AUDIT_EVENTS |
1973 | audit_event(SSH_AUTH_SUCCESS); | |
1974 | #endif | |
1975 | ||
bd5d5d2a | 1976 | #ifdef GSSAPI |
6f25cbdd | 1977 | if (options.gss_authentication && options.gss_deleg_creds) { |
bd5d5d2a | 1978 | temporarily_use_uid(authctxt->pw); |
1979 | ssh_gssapi_storecreds(); | |
1980 | restore_uid(); | |
1981 | } | |
1982 | #endif | |
1983 | #ifdef USE_PAM | |
1984 | if (options.use_pam) { | |
1985 | do_pam_setcred(1); | |
1986 | do_pam_session(); | |
1987 | } | |
1988 | #endif | |
1989 | ||
2980ea68 | 1990 | /* |
1991 | * In privilege separation, we fork another child and prepare | |
1992 | * file descriptor passing. | |
1993 | */ | |
1994 | if (use_privsep) { | |
1995 | privsep_postauth(authctxt); | |
1996 | /* the monitor process [priv] will not return */ | |
1997 | if (!compat20) | |
1998 | destroy_sensitive_data(); | |
1999 | } | |
2000 | ||
6f25cbdd | 2001 | packet_set_timeout(options.client_alive_interval, |
2002 | options.client_alive_count_max); | |
2003 | ||
416fd2a8 | 2004 | /* Start session. */ |
2980ea68 | 2005 | do_authenticated(authctxt); |
2006 | ||
3c0ef626 | 2007 | /* The connection has been terminated. */ |
6f25cbdd | 2008 | packet_get_state(MODE_IN, NULL, NULL, NULL, &ibytes); |
2009 | packet_get_state(MODE_OUT, NULL, NULL, NULL, &obytes); | |
2010 | verbose("Transferred: sent %llu, received %llu bytes", obytes, ibytes); | |
2011 | ||
2012 | verbose("Closing connection to %.500s port %d", remote_ip, remote_port); | |
3c0ef626 | 2013 | |
2014 | #ifdef USE_PAM | |
70791e56 | 2015 | if (options.use_pam) |
2016 | finish_pam(); | |
3c0ef626 | 2017 | #endif /* USE_PAM */ |
2018 | ||
34fee935 | 2019 | #ifdef SSH_AUDIT_EVENTS |
2020 | PRIVSEP(audit_event(SSH_CONNECTION_CLOSE)); | |
2021 | #endif | |
2022 | ||
3c0ef626 | 2023 | packet_close(); |
2980ea68 | 2024 | |
2025 | if (use_privsep) | |
2026 | mm_terminate(); | |
2027 | ||
3c0ef626 | 2028 | exit(0); |
2029 | } | |
2030 | ||
2980ea68 | 2031 | /* |
2032 | * Decrypt session_key_int using our private server key and private host key | |
2033 | * (key with larger modulus first). | |
2034 | */ | |
2035 | int | |
2036 | ssh1_session_key(BIGNUM *session_key_int) | |
2037 | { | |
2038 | int rsafail = 0; | |
2039 | ||
2e437378 | 2040 | if (BN_cmp(sensitive_data.server_key->rsa->n, |
2041 | sensitive_data.ssh1_host_key->rsa->n) > 0) { | |
2980ea68 | 2042 | /* Server key has bigger modulus. */ |
2043 | if (BN_num_bits(sensitive_data.server_key->rsa->n) < | |
2e437378 | 2044 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + |
2045 | SSH_KEY_BITS_RESERVED) { | |
2046 | fatal("do_connection: %s: " | |
2047 | "server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d", | |
2980ea68 | 2048 | get_remote_ipaddr(), |
2049 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
2050 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), | |
2051 | SSH_KEY_BITS_RESERVED); | |
2052 | } | |
2053 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
2054 | sensitive_data.server_key->rsa) <= 0) | |
2055 | rsafail++; | |
2056 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
2057 | sensitive_data.ssh1_host_key->rsa) <= 0) | |
2058 | rsafail++; | |
2059 | } else { | |
2060 | /* Host key has bigger modulus (or they are equal). */ | |
2061 | if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) < | |
2e437378 | 2062 | BN_num_bits(sensitive_data.server_key->rsa->n) + |
2063 | SSH_KEY_BITS_RESERVED) { | |
2064 | fatal("do_connection: %s: " | |
2065 | "host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d", | |
2980ea68 | 2066 | get_remote_ipaddr(), |
2067 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), | |
2068 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
2069 | SSH_KEY_BITS_RESERVED); | |
2070 | } | |
2071 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
2072 | sensitive_data.ssh1_host_key->rsa) < 0) | |
2073 | rsafail++; | |
2074 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
2075 | sensitive_data.server_key->rsa) < 0) | |
2076 | rsafail++; | |
2077 | } | |
2078 | return (rsafail); | |
2079 | } | |
3c0ef626 | 2080 | /* |
2081 | * SSH1 key exchange | |
2082 | */ | |
2083 | static void | |
2084 | do_ssh1_kex(void) | |
2085 | { | |
2086 | int i, len; | |
3c0ef626 | 2087 | int rsafail = 0; |
2088 | BIGNUM *session_key_int; | |
2089 | u_char session_key[SSH_SESSION_KEY_LENGTH]; | |
2090 | u_char cookie[8]; | |
2091 | u_int cipher_type, auth_mask, protocol_flags; | |
3c0ef626 | 2092 | |
2093 | /* | |
2094 | * Generate check bytes that the client must send back in the user | |
2095 | * packet in order for it to be accepted; this is used to defy ip | |
2096 | * spoofing attacks. Note that this only works against somebody | |
2097 | * doing IP spoofing from a remote machine; any machine on the local | |
2098 | * network can still see outgoing packets and catch the random | |
2099 | * cookie. This only affects rhosts authentication, and this is one | |
2100 | * of the reasons why it is inherently insecure. | |
2101 | */ | |
6f25cbdd | 2102 | arc4random_buf(cookie, sizeof(cookie)); |
3c0ef626 | 2103 | |
2104 | /* | |
2105 | * Send our public key. We include in the packet 64 bits of random | |
2106 | * data that must be matched in the reply in order to prevent IP | |
2107 | * spoofing. | |
2108 | */ | |
2109 | packet_start(SSH_SMSG_PUBLIC_KEY); | |
2110 | for (i = 0; i < 8; i++) | |
2111 | packet_put_char(cookie[i]); | |
2112 | ||
2113 | /* Store our public server RSA key. */ | |
2114 | packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n)); | |
2115 | packet_put_bignum(sensitive_data.server_key->rsa->e); | |
2116 | packet_put_bignum(sensitive_data.server_key->rsa->n); | |
2117 | ||
2118 | /* Store our public host RSA key. */ | |
2119 | packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); | |
2120 | packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e); | |
2121 | packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n); | |
2122 | ||
2123 | /* Put protocol flags. */ | |
2124 | packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN); | |
2125 | ||
2126 | /* Declare which ciphers we support. */ | |
2127 | packet_put_int(cipher_mask_ssh1(0)); | |
2128 | ||
2129 | /* Declare supported authentication types. */ | |
2130 | auth_mask = 0; | |
3c0ef626 | 2131 | if (options.rhosts_rsa_authentication) |
2132 | auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA; | |
2133 | if (options.rsa_authentication) | |
2134 | auth_mask |= 1 << SSH_AUTH_RSA; | |
ff2d7a98 | 2135 | if (options.challenge_response_authentication == 1) |
2136 | auth_mask |= 1 << SSH_AUTH_TIS; | |
3c0ef626 | 2137 | if (options.password_authentication) |
2138 | auth_mask |= 1 << SSH_AUTH_PASSWORD; | |
2139 | packet_put_int(auth_mask); | |
2140 | ||
2141 | /* Send the packet and wait for it to be sent. */ | |
2142 | packet_send(); | |
2143 | packet_write_wait(); | |
2144 | ||
2145 | debug("Sent %d bit server key and %d bit host key.", | |
2146 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
2147 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); | |
2148 | ||
2149 | /* Read clients reply (cipher type and session key). */ | |
1e608e42 | 2150 | packet_read_expect(SSH_CMSG_SESSION_KEY); |
3c0ef626 | 2151 | |
2152 | /* Get cipher type and check whether we accept this. */ | |
2153 | cipher_type = packet_get_char(); | |
2154 | ||
2155 | if (!(cipher_mask_ssh1(0) & (1 << cipher_type))) | |
2156 | packet_disconnect("Warning: client selects unsupported cipher."); | |
2157 | ||
2158 | /* Get check bytes from the packet. These must match those we | |
2159 | sent earlier with the public key packet. */ | |
2160 | for (i = 0; i < 8; i++) | |
2161 | if (cookie[i] != packet_get_char()) | |
2162 | packet_disconnect("IP Spoofing check bytes do not match."); | |
2163 | ||
2164 | debug("Encryption type: %.200s", cipher_name(cipher_type)); | |
2165 | ||
2166 | /* Get the encrypted integer. */ | |
1e608e42 | 2167 | if ((session_key_int = BN_new()) == NULL) |
2168 | fatal("do_ssh1_kex: BN_new failed"); | |
2169 | packet_get_bignum(session_key_int); | |
3c0ef626 | 2170 | |
2171 | protocol_flags = packet_get_int(); | |
2172 | packet_set_protocol_flags(protocol_flags); | |
1e608e42 | 2173 | packet_check_eom(); |
3c0ef626 | 2174 | |
2980ea68 | 2175 | /* Decrypt session_key_int using host/server keys */ |
2176 | rsafail = PRIVSEP(ssh1_session_key(session_key_int)); | |
2177 | ||
3c0ef626 | 2178 | /* |
2179 | * Extract session key from the decrypted integer. The key is in the | |
2180 | * least significant 256 bits of the integer; the first byte of the | |
2181 | * key is in the highest bits. | |
2182 | */ | |
2183 | if (!rsafail) { | |
2e437378 | 2184 | (void) BN_mask_bits(session_key_int, sizeof(session_key) * 8); |
3c0ef626 | 2185 | len = BN_num_bytes(session_key_int); |
34fee935 | 2186 | if (len < 0 || (u_int)len > sizeof(session_key)) { |
2e437378 | 2187 | error("do_ssh1_kex: bad session key len from %s: " |
3c0ef626 | 2188 | "session_key_int %d > sizeof(session_key) %lu", |
2189 | get_remote_ipaddr(), len, (u_long)sizeof(session_key)); | |
2190 | rsafail++; | |
2191 | } else { | |
2192 | memset(session_key, 0, sizeof(session_key)); | |
2193 | BN_bn2bin(session_key_int, | |
2194 | session_key + sizeof(session_key) - len); | |
2195 | ||
1b56ff3d | 2196 | derive_ssh1_session_id( |
3c0ef626 | 2197 | sensitive_data.ssh1_host_key->rsa->n, |
1b56ff3d | 2198 | sensitive_data.server_key->rsa->n, |
2199 | cookie, session_id); | |
3c0ef626 | 2200 | /* |
2201 | * Xor the first 16 bytes of the session key with the | |
2202 | * session id. | |
2203 | */ | |
2204 | for (i = 0; i < 16; i++) | |
2205 | session_key[i] ^= session_id[i]; | |
2206 | } | |
2207 | } | |
2208 | if (rsafail) { | |
2209 | int bytes = BN_num_bytes(session_key_int); | |
1e608e42 | 2210 | u_char *buf = xmalloc(bytes); |
3c0ef626 | 2211 | MD5_CTX md; |
2212 | ||
70791e56 | 2213 | logit("do_connection: generating a fake encryption key"); |
3c0ef626 | 2214 | BN_bn2bin(session_key_int, buf); |
2215 | MD5_Init(&md); | |
2216 | MD5_Update(&md, buf, bytes); | |
2217 | MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); | |
2218 | MD5_Final(session_key, &md); | |
2219 | MD5_Init(&md); | |
2220 | MD5_Update(&md, session_key, 16); | |
2221 | MD5_Update(&md, buf, bytes); | |
2222 | MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); | |
2223 | MD5_Final(session_key + 16, &md); | |
2224 | memset(buf, 0, bytes); | |
2225 | xfree(buf); | |
2226 | for (i = 0; i < 16; i++) | |
2227 | session_id[i] = session_key[i] ^ session_key[i + 16]; | |
2228 | } | |
2980ea68 | 2229 | /* Destroy the private and public keys. No longer. */ |
3c0ef626 | 2230 | destroy_sensitive_data(); |
2231 | ||
2980ea68 | 2232 | if (use_privsep) |
2233 | mm_ssh1_session_id(session_id); | |
2234 | ||
3c0ef626 | 2235 | /* Destroy the decrypted integer. It is no longer needed. */ |
2236 | BN_clear_free(session_key_int); | |
2237 | ||
2238 | /* Set the session key. From this on all communications will be encrypted. */ | |
2239 | packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type); | |
2240 | ||
2241 | /* Destroy our copy of the session key. It is no longer needed. */ | |
2242 | memset(session_key, 0, sizeof(session_key)); | |
2243 | ||
2244 | debug("Received session key; encryption turned on."); | |
2245 | ||
ff2d7a98 | 2246 | /* Send an acknowledgment packet. Note that this packet is sent encrypted. */ |
3c0ef626 | 2247 | packet_start(SSH_SMSG_SUCCESS); |
2248 | packet_send(); | |
2249 | packet_write_wait(); | |
2250 | } | |
2251 | ||
2252 | /* | |
2253 | * SSH2 key exchange: diffie-hellman-group1-sha1 | |
2254 | */ | |
2255 | static void | |
2256 | do_ssh2_kex(void) | |
2257 | { | |
2258 | Kex *kex; | |
2259 | ||
bd5d5d2a | 2260 | myflag++; |
2261 | debug ("MYFLAG IS %d", myflag); | |
3c0ef626 | 2262 | if (options.ciphers != NULL) { |
2263 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = | |
2264 | myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; | |
e00da40d | 2265 | } else if (options.none_enabled == 1) { |
2266 | debug ("WARNING: None cipher enabled"); | |
2267 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = | |
2268 | myproposal[PROPOSAL_ENC_ALGS_STOC] = KEX_ENCRYPT_INCLUDE_NONE; | |
3c0ef626 | 2269 | } |
2270 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = | |
2271 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]); | |
2272 | myproposal[PROPOSAL_ENC_ALGS_STOC] = | |
2273 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); | |
2274 | ||
2275 | if (options.macs != NULL) { | |
2276 | myproposal[PROPOSAL_MAC_ALGS_CTOS] = | |
2277 | myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; | |
2278 | } | |
34fee935 | 2279 | if (options.compression == COMP_NONE) { |
ff2d7a98 | 2280 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = |
2281 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "none"; | |
34fee935 | 2282 | } else if (options.compression == COMP_DELAYED) { |
2283 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = | |
2284 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com"; | |
ff2d7a98 | 2285 | } |
2e437378 | 2286 | |
3c0ef626 | 2287 | myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = list_hostkey_types(); |
2288 | ||
5598e598 | 2289 | #ifdef GSSAPI |
34fee935 | 2290 | { |
5598e598 | 2291 | char *orig; |
2292 | char *gss = NULL; | |
2293 | char *newstr = NULL; | |
34fee935 | 2294 | orig = myproposal[PROPOSAL_KEX_ALGS]; |
2295 | ||
2296 | /* | |
2e437378 | 2297 | * If we don't have a host key, then there's no point advertising |
2298 | * the other key exchange algorithms | |
34fee935 | 2299 | */ |
2300 | ||
2301 | if (strlen(myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS]) == 0) | |
2302 | orig = NULL; | |
2303 | ||
2304 | if (options.gss_keyex) | |
2305 | gss = ssh_gssapi_server_mechanisms(); | |
2306 | else | |
2307 | gss = NULL; | |
2308 | ||
2e437378 | 2309 | if (gss && orig) |
2310 | xasprintf(&newstr, "%s,%s", gss, orig); | |
2311 | else if (gss) | |
34fee935 | 2312 | newstr = gss; |
2e437378 | 2313 | else if (orig) |
34fee935 | 2314 | newstr = orig; |
2e437378 | 2315 | |
34fee935 | 2316 | /* |
2317 | * If we've got GSSAPI mechanisms, then we've got the 'null' host | |
2318 | * key alg, but we can't tell people about it unless its the only | |
2319 | * host key algorithm we support | |
2320 | */ | |
2321 | if (gss && (strlen(myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS])) == 0) | |
2322 | myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = "null"; | |
2323 | ||
5598e598 | 2324 | if (newstr) |
34fee935 | 2325 | myproposal[PROPOSAL_KEX_ALGS] = newstr; |
5598e598 | 2326 | else |
2327 | fatal("No supported key exchange algorithms"); | |
34fee935 | 2328 | } |
5598e598 | 2329 | #endif |
2330 | ||
2e437378 | 2331 | /* start key exchange */ |
2332 | kex = kex_setup(myproposal); | |
2333 | kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server; | |
1b56ff3d | 2334 | kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server; |
1c14df9e | 2335 | kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; |
2e437378 | 2336 | kex->kex[KEX_DH_GEX_SHA256] = kexgex_server; |
1c14df9e | 2337 | #ifdef GSSAPI |
46201ce0 | 2338 | if (options.gss_keyex) { |
2339 | kex->kex[KEX_GSS_GRP1_SHA1] = kexgss_server; | |
2340 | kex->kex[KEX_GSS_GRP14_SHA1] = kexgss_server; | |
2341 | kex->kex[KEX_GSS_GEX_SHA1] = kexgss_server; | |
2342 | } | |
1c14df9e | 2343 | #endif |
2e437378 | 2344 | kex->server = 1; |
2345 | kex->client_version_string=client_version_string; | |
2346 | kex->server_version_string=server_version_string; | |
3c0ef626 | 2347 | kex->load_host_key=&get_hostkey_by_type; |
2980ea68 | 2348 | kex->host_key_index=&get_hostkey_index; |
3c0ef626 | 2349 | |
2350 | xxx_kex = kex; | |
2351 | ||
2352 | dispatch_run(DISPATCH_BLOCK, &kex->done, kex); | |
2353 | ||
2354 | session_id2 = kex->session_id; | |
2355 | session_id2_len = kex->session_id_len; | |
2356 | ||
2357 | #ifdef DEBUG_KEXDH | |
2358 | /* send 1st encrypted/maced/compressed message */ | |
2359 | packet_start(SSH2_MSG_IGNORE); | |
2360 | packet_put_cstring("markus"); | |
2361 | packet_send(); | |
2362 | packet_write_wait(); | |
2363 | #endif | |
2364 | debug("KEX done"); | |
2365 | } | |
416fd2a8 | 2366 | |
2367 | /* server specific fatal cleanup */ | |
2368 | void | |
2369 | cleanup_exit(int i) | |
2370 | { | |
2371 | if (the_authctxt) | |
2372 | do_cleanup(the_authctxt); | |
34fee935 | 2373 | #ifdef SSH_AUDIT_EVENTS |
2374 | /* done after do_cleanup so it can cancel the PAM auth 'thread' */ | |
2375 | if (!use_privsep || mm_is_monitor()) | |
2376 | audit_event(SSH_CONNECTION_ABANDON); | |
2377 | #endif | |
416fd2a8 | 2378 | _exit(i); |
2379 | } |