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3c0ef626 | 1 | /* |
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 | * This program is the ssh daemon. It listens for connections from clients, | |
6 | * and performs authentication, executes use commands or shell, and forwards | |
7 | * information to/from the application to the user client over an encrypted | |
8 | * connection. This can also handle forwarding of X11, TCP/IP, and | |
9 | * authentication agent connections. | |
10 | * | |
11 | * As far as I am concerned, the code I have written for this software | |
12 | * can be used freely for any purpose. Any derived versions of this | |
13 | * software must be clearly marked as such, and if the derived work is | |
14 | * incompatible with the protocol description in the RFC file, it must be | |
15 | * called by a name other than "ssh" or "Secure Shell". | |
16 | * | |
17 | * SSH2 implementation: | |
2980ea68 | 18 | * Privilege Separation: |
3c0ef626 | 19 | * |
2980ea68 | 20 | * Copyright (c) 2000, 2001, 2002 Markus Friedl. All rights reserved. |
21 | * Copyright (c) 2002 Niels Provos. All rights reserved. | |
3c0ef626 | 22 | * |
23 | * Redistribution and use in source and binary forms, with or without | |
24 | * modification, are permitted provided that the following conditions | |
25 | * are met: | |
26 | * 1. Redistributions of source code must retain the above copyright | |
27 | * notice, this list of conditions and the following disclaimer. | |
28 | * 2. Redistributions in binary form must reproduce the above copyright | |
29 | * notice, this list of conditions and the following disclaimer in the | |
30 | * documentation and/or other materials provided with the distribution. | |
31 | * | |
32 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR | |
33 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES | |
34 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. | |
35 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, | |
36 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
37 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
38 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
39 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
40 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF | |
41 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
42 | */ | |
43 | ||
44 | #include "includes.h" | |
e00da40d | 45 | RCSID("$OpenBSD: sshd.c,v 1.318 2005/12/24 02:27:41 djm Exp $"); |
3c0ef626 | 46 | |
47 | #include <openssl/dh.h> | |
48 | #include <openssl/bn.h> | |
1e608e42 | 49 | #include <openssl/md5.h> |
2980ea68 | 50 | #include <openssl/rand.h> |
51 | #ifdef HAVE_SECUREWARE | |
52 | #include <sys/security.h> | |
53 | #include <prot.h> | |
54 | #endif | |
3c0ef626 | 55 | |
56 | #include "ssh.h" | |
57 | #include "ssh1.h" | |
58 | #include "ssh2.h" | |
59 | #include "xmalloc.h" | |
60 | #include "rsa.h" | |
61 | #include "sshpty.h" | |
62 | #include "packet.h" | |
3c0ef626 | 63 | #include "log.h" |
64 | #include "servconf.h" | |
65 | #include "uidswap.h" | |
66 | #include "compat.h" | |
67 | #include "buffer.h" | |
1b56ff3d | 68 | #include "bufaux.h" |
3c0ef626 | 69 | #include "cipher.h" |
70 | #include "kex.h" | |
71 | #include "key.h" | |
72 | #include "dh.h" | |
73 | #include "myproposal.h" | |
74 | #include "authfile.h" | |
75 | #include "pathnames.h" | |
76 | #include "atomicio.h" | |
77 | #include "canohost.h" | |
78 | #include "auth.h" | |
79 | #include "misc.h" | |
1b56ff3d | 80 | #include "msg.h" |
3c0ef626 | 81 | #include "dispatch.h" |
82 | #include "channels.h" | |
2980ea68 | 83 | #include "session.h" |
84 | #include "monitor_mm.h" | |
85 | #include "monitor.h" | |
86 | #include "monitor_wrap.h" | |
87 | #include "monitor_fdpass.h" | |
3c0ef626 | 88 | |
34fee935 | 89 | #ifdef USE_SECURITY_SESSION_API |
90 | #include <Security/AuthSession.h> | |
5598e598 | 91 | #endif |
92 | ||
3c0ef626 | 93 | #ifdef LIBWRAP |
94 | #include <tcpd.h> | |
95 | #include <syslog.h> | |
96 | int allow_severity = LOG_INFO; | |
97 | int deny_severity = LOG_WARNING; | |
98 | #endif /* LIBWRAP */ | |
99 | ||
100 | #ifndef O_NOCTTY | |
101 | #define O_NOCTTY 0 | |
102 | #endif | |
103 | ||
1b56ff3d | 104 | /* Re-exec fds */ |
105 | #define REEXEC_DEVCRYPTO_RESERVED_FD (STDERR_FILENO + 1) | |
106 | #define REEXEC_STARTUP_PIPE_FD (STDERR_FILENO + 2) | |
107 | #define REEXEC_CONFIG_PASS_FD (STDERR_FILENO + 3) | |
108 | #define REEXEC_MIN_FREE_FD (STDERR_FILENO + 4) | |
109 | ||
3c0ef626 | 110 | extern char *__progname; |
3c0ef626 | 111 | |
112 | /* Server configuration options. */ | |
113 | ServerOptions options; | |
114 | ||
115 | /* Name of the server configuration file. */ | |
ae43c103 | 116 | char *config_file_name; |
3c0ef626 | 117 | |
3c0ef626 | 118 | /* |
119 | * Debug mode flag. This can be set on the command line. If debug | |
120 | * mode is enabled, extra debugging output will be sent to the system | |
121 | * log, the daemon will not go to background, and will exit after processing | |
122 | * the first connection. | |
123 | */ | |
124 | int debug_flag = 0; | |
125 | ||
126 | /* Flag indicating that the daemon should only test the configuration and keys. */ | |
127 | int test_flag = 0; | |
128 | ||
129 | /* Flag indicating that the daemon is being started from inetd. */ | |
130 | int inetd_flag = 0; | |
131 | ||
132 | /* Flag indicating that sshd should not detach and become a daemon. */ | |
133 | int no_daemon_flag = 0; | |
134 | ||
135 | /* debug goes to stderr unless inetd_flag is set */ | |
136 | int log_stderr = 0; | |
137 | ||
138 | /* Saved arguments to main(). */ | |
139 | char **saved_argv; | |
140 | int saved_argc; | |
141 | ||
1b56ff3d | 142 | /* re-exec */ |
143 | int rexeced_flag = 0; | |
144 | int rexec_flag = 1; | |
145 | int rexec_argc = 0; | |
146 | char **rexec_argv; | |
147 | ||
3c0ef626 | 148 | /* |
149 | * The sockets that the server is listening; this is used in the SIGHUP | |
150 | * signal handler. | |
151 | */ | |
152 | #define MAX_LISTEN_SOCKS 16 | |
153 | int listen_socks[MAX_LISTEN_SOCKS]; | |
154 | int num_listen_socks = 0; | |
155 | ||
156 | /* | |
157 | * the client's version string, passed by sshd2 in compat mode. if != NULL, | |
158 | * sshd will skip the version-number exchange | |
159 | */ | |
160 | char *client_version_string = NULL; | |
161 | char *server_version_string = NULL; | |
162 | ||
163 | /* for rekeying XXX fixme */ | |
164 | Kex *xxx_kex; | |
165 | ||
166 | /* | |
167 | * Any really sensitive data in the application is contained in this | |
168 | * structure. The idea is that this structure could be locked into memory so | |
169 | * that the pages do not get written into swap. However, there are some | |
170 | * problems. The private key contains BIGNUMs, and we do not (in principle) | |
171 | * have access to the internals of them, and locking just the structure is | |
172 | * not very useful. Currently, memory locking is not implemented. | |
173 | */ | |
174 | struct { | |
175 | Key *server_key; /* ephemeral server key */ | |
176 | Key *ssh1_host_key; /* ssh1 host key */ | |
177 | Key **host_keys; /* all private host keys */ | |
178 | int have_ssh1_key; | |
179 | int have_ssh2_key; | |
180 | u_char ssh1_cookie[SSH_SESSION_KEY_LENGTH]; | |
181 | } sensitive_data; | |
182 | ||
183 | /* | |
184 | * Flag indicating whether the RSA server key needs to be regenerated. | |
185 | * Is set in the SIGALRM handler and cleared when the key is regenerated. | |
186 | */ | |
1e608e42 | 187 | static volatile sig_atomic_t key_do_regen = 0; |
3c0ef626 | 188 | |
189 | /* This is set to true when a signal is received. */ | |
1e608e42 | 190 | static volatile sig_atomic_t received_sighup = 0; |
191 | static volatile sig_atomic_t received_sigterm = 0; | |
3c0ef626 | 192 | |
193 | /* session identifier, used by RSA-auth */ | |
194 | u_char session_id[16]; | |
195 | ||
196 | /* same for ssh2 */ | |
197 | u_char *session_id2 = NULL; | |
70791e56 | 198 | u_int session_id2_len = 0; |
3c0ef626 | 199 | |
200 | /* record remote hostname or ip */ | |
201 | u_int utmp_len = MAXHOSTNAMELEN; | |
202 | ||
1e608e42 | 203 | /* options.max_startup sized array of fd ints */ |
204 | int *startup_pipes = NULL; | |
205 | int startup_pipe; /* in child */ | |
206 | ||
2980ea68 | 207 | /* variables used for privilege separation */ |
1c14df9e | 208 | int use_privsep; |
416fd2a8 | 209 | struct monitor *pmonitor = NULL; |
2980ea68 | 210 | |
416fd2a8 | 211 | /* global authentication context */ |
212 | Authctxt *the_authctxt = NULL; | |
213 | ||
1b56ff3d | 214 | /* message to be displayed after login */ |
215 | Buffer loginmsg; | |
216 | ||
3c0ef626 | 217 | /* Prototypes for various functions defined later in this file. */ |
218 | void destroy_sensitive_data(void); | |
2980ea68 | 219 | void demote_sensitive_data(void); |
3c0ef626 | 220 | |
221 | static void do_ssh1_kex(void); | |
222 | static void do_ssh2_kex(void); | |
223 | ||
224 | /* | |
225 | * Close all listening sockets | |
226 | */ | |
227 | static void | |
228 | close_listen_socks(void) | |
229 | { | |
230 | int i; | |
ff2d7a98 | 231 | |
3c0ef626 | 232 | for (i = 0; i < num_listen_socks; i++) |
233 | close(listen_socks[i]); | |
234 | num_listen_socks = -1; | |
235 | } | |
236 | ||
1e608e42 | 237 | static void |
238 | close_startup_pipes(void) | |
239 | { | |
240 | int i; | |
ff2d7a98 | 241 | |
1e608e42 | 242 | if (startup_pipes) |
243 | for (i = 0; i < options.max_startups; i++) | |
244 | if (startup_pipes[i] != -1) | |
245 | close(startup_pipes[i]); | |
246 | } | |
247 | ||
3c0ef626 | 248 | /* |
249 | * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP; | |
250 | * the effect is to reread the configuration file (and to regenerate | |
251 | * the server key). | |
252 | */ | |
253 | static void | |
254 | sighup_handler(int sig) | |
255 | { | |
1e608e42 | 256 | int save_errno = errno; |
257 | ||
3c0ef626 | 258 | received_sighup = 1; |
259 | signal(SIGHUP, sighup_handler); | |
1e608e42 | 260 | errno = save_errno; |
3c0ef626 | 261 | } |
262 | ||
263 | /* | |
264 | * Called from the main program after receiving SIGHUP. | |
265 | * Restarts the server. | |
266 | */ | |
267 | static void | |
268 | sighup_restart(void) | |
269 | { | |
70791e56 | 270 | logit("Received SIGHUP; restarting."); |
3c0ef626 | 271 | close_listen_socks(); |
1e608e42 | 272 | close_startup_pipes(); |
3c0ef626 | 273 | execv(saved_argv[0], saved_argv); |
70791e56 | 274 | logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0], |
ff2d7a98 | 275 | strerror(errno)); |
3c0ef626 | 276 | exit(1); |
277 | } | |
278 | ||
279 | /* | |
280 | * Generic signal handler for terminating signals in the master daemon. | |
281 | */ | |
282 | static void | |
283 | sigterm_handler(int sig) | |
284 | { | |
285 | received_sigterm = sig; | |
286 | } | |
287 | ||
288 | /* | |
289 | * SIGCHLD handler. This is called whenever a child dies. This will then | |
290 | * reap any zombies left by exited children. | |
291 | */ | |
292 | static void | |
293 | main_sigchld_handler(int sig) | |
294 | { | |
295 | int save_errno = errno; | |
ff2d7a98 | 296 | pid_t pid; |
3c0ef626 | 297 | int status; |
298 | ||
2980ea68 | 299 | while ((pid = waitpid(-1, &status, WNOHANG)) > 0 || |
300 | (pid < 0 && errno == EINTR)) | |
3c0ef626 | 301 | ; |
302 | ||
303 | signal(SIGCHLD, main_sigchld_handler); | |
304 | errno = save_errno; | |
305 | } | |
306 | ||
307 | /* | |
308 | * Signal handler for the alarm after the login grace period has expired. | |
309 | */ | |
310 | static void | |
311 | grace_alarm_handler(int sig) | |
312 | { | |
313 | /* XXX no idea how fix this signal handler */ | |
314 | ||
416fd2a8 | 315 | if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0) |
316 | kill(pmonitor->m_pid, SIGALRM); | |
317 | ||
3c0ef626 | 318 | /* Log error and exit. */ |
e54b3d7c | 319 | fatal("Timeout before authentication for %s", get_remote_ipaddr()); |
3c0ef626 | 320 | } |
321 | ||
322 | /* | |
323 | * Signal handler for the key regeneration alarm. Note that this | |
324 | * alarm only occurs in the daemon waiting for connections, and it does not | |
325 | * do anything with the private key or random state before forking. | |
326 | * Thus there should be no concurrency control/asynchronous execution | |
327 | * problems. | |
328 | */ | |
329 | static void | |
330 | generate_ephemeral_server_key(void) | |
331 | { | |
e54b3d7c | 332 | u_int32_t rnd = 0; |
3c0ef626 | 333 | int i; |
334 | ||
335 | verbose("Generating %s%d bit RSA key.", | |
336 | sensitive_data.server_key ? "new " : "", options.server_key_bits); | |
337 | if (sensitive_data.server_key != NULL) | |
338 | key_free(sensitive_data.server_key); | |
339 | sensitive_data.server_key = key_generate(KEY_RSA1, | |
340 | options.server_key_bits); | |
341 | verbose("RSA key generation complete."); | |
342 | ||
343 | for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) { | |
344 | if (i % 4 == 0) | |
e54b3d7c | 345 | rnd = arc4random(); |
346 | sensitive_data.ssh1_cookie[i] = rnd & 0xff; | |
347 | rnd >>= 8; | |
3c0ef626 | 348 | } |
349 | arc4random_stir(); | |
350 | } | |
351 | ||
352 | static void | |
353 | key_regeneration_alarm(int sig) | |
354 | { | |
355 | int save_errno = errno; | |
ff2d7a98 | 356 | |
3c0ef626 | 357 | signal(SIGALRM, SIG_DFL); |
358 | errno = save_errno; | |
359 | key_do_regen = 1; | |
360 | } | |
361 | ||
362 | static void | |
363 | sshd_exchange_identification(int sock_in, int sock_out) | |
364 | { | |
34fee935 | 365 | u_int i; |
366 | int mismatch; | |
3c0ef626 | 367 | int remote_major, remote_minor; |
368 | int major, minor; | |
369 | char *s; | |
370 | char buf[256]; /* Must not be larger than remote_version. */ | |
371 | char remote_version[256]; /* Must be at least as big as buf. */ | |
372 | ||
373 | if ((options.protocol & SSH_PROTO_1) && | |
374 | (options.protocol & SSH_PROTO_2)) { | |
375 | major = PROTOCOL_MAJOR_1; | |
376 | minor = 99; | |
377 | } else if (options.protocol & SSH_PROTO_2) { | |
378 | major = PROTOCOL_MAJOR_2; | |
379 | minor = PROTOCOL_MINOR_2; | |
380 | } else { | |
381 | major = PROTOCOL_MAJOR_1; | |
382 | minor = PROTOCOL_MINOR_1; | |
383 | } | |
34fee935 | 384 | snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", major, minor, SSH_RELEASE); |
3c0ef626 | 385 | server_version_string = xstrdup(buf); |
386 | ||
70791e56 | 387 | /* Send our protocol version identification. */ |
388 | if (atomicio(vwrite, sock_out, server_version_string, | |
389 | strlen(server_version_string)) | |
390 | != strlen(server_version_string)) { | |
391 | logit("Could not write ident string to %s", get_remote_ipaddr()); | |
416fd2a8 | 392 | cleanup_exit(255); |
70791e56 | 393 | } |
394 | ||
395 | /* Read other sides version identification. */ | |
396 | memset(buf, 0, sizeof(buf)); | |
397 | for (i = 0; i < sizeof(buf) - 1; i++) { | |
398 | if (atomicio(read, sock_in, &buf[i], 1) != 1) { | |
399 | logit("Did not receive identification string from %s", | |
400 | get_remote_ipaddr()); | |
416fd2a8 | 401 | cleanup_exit(255); |
3c0ef626 | 402 | } |
70791e56 | 403 | if (buf[i] == '\r') { |
404 | buf[i] = 0; | |
405 | /* Kludge for F-Secure Macintosh < 1.0.2 */ | |
406 | if (i == 12 && | |
407 | strncmp(buf, "SSH-1.5-W1.0", 12) == 0) | |
3c0ef626 | 408 | break; |
70791e56 | 409 | continue; |
410 | } | |
411 | if (buf[i] == '\n') { | |
412 | buf[i] = 0; | |
413 | break; | |
3c0ef626 | 414 | } |
3c0ef626 | 415 | } |
70791e56 | 416 | buf[sizeof(buf) - 1] = 0; |
417 | client_version_string = xstrdup(buf); | |
3c0ef626 | 418 | |
419 | /* | |
420 | * Check that the versions match. In future this might accept | |
421 | * several versions and set appropriate flags to handle them. | |
422 | */ | |
423 | if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n", | |
424 | &remote_major, &remote_minor, remote_version) != 3) { | |
425 | s = "Protocol mismatch.\n"; | |
70791e56 | 426 | (void) atomicio(vwrite, sock_out, s, strlen(s)); |
3c0ef626 | 427 | close(sock_in); |
428 | close(sock_out); | |
70791e56 | 429 | logit("Bad protocol version identification '%.100s' from %s", |
3c0ef626 | 430 | client_version_string, get_remote_ipaddr()); |
416fd2a8 | 431 | cleanup_exit(255); |
3c0ef626 | 432 | } |
433 | debug("Client protocol version %d.%d; client software version %.100s", | |
1e608e42 | 434 | remote_major, remote_minor, remote_version); |
3c0ef626 | 435 | |
436 | compat_datafellows(remote_version); | |
437 | ||
e54b3d7c | 438 | if (datafellows & SSH_BUG_PROBE) { |
70791e56 | 439 | logit("probed from %s with %s. Don't panic.", |
e54b3d7c | 440 | get_remote_ipaddr(), client_version_string); |
416fd2a8 | 441 | cleanup_exit(255); |
e54b3d7c | 442 | } |
443 | ||
3c0ef626 | 444 | if (datafellows & SSH_BUG_SCANNER) { |
70791e56 | 445 | logit("scanned from %s with %s. Don't panic.", |
3c0ef626 | 446 | get_remote_ipaddr(), client_version_string); |
416fd2a8 | 447 | cleanup_exit(255); |
3c0ef626 | 448 | } |
449 | ||
450 | mismatch = 0; | |
1e608e42 | 451 | switch (remote_major) { |
3c0ef626 | 452 | case 1: |
453 | if (remote_minor == 99) { | |
454 | if (options.protocol & SSH_PROTO_2) | |
455 | enable_compat20(); | |
456 | else | |
457 | mismatch = 1; | |
458 | break; | |
459 | } | |
460 | if (!(options.protocol & SSH_PROTO_1)) { | |
461 | mismatch = 1; | |
462 | break; | |
463 | } | |
464 | if (remote_minor < 3) { | |
465 | packet_disconnect("Your ssh version is too old and " | |
466 | "is no longer supported. Please install a newer version."); | |
467 | } else if (remote_minor == 3) { | |
468 | /* note that this disables agent-forwarding */ | |
469 | enable_compat13(); | |
470 | } | |
471 | break; | |
472 | case 2: | |
473 | if (options.protocol & SSH_PROTO_2) { | |
474 | enable_compat20(); | |
475 | break; | |
476 | } | |
477 | /* FALLTHROUGH */ | |
478 | default: | |
479 | mismatch = 1; | |
480 | break; | |
481 | } | |
482 | chop(server_version_string); | |
483 | debug("Local version string %.200s", server_version_string); | |
484 | ||
485 | if (mismatch) { | |
486 | s = "Protocol major versions differ.\n"; | |
70791e56 | 487 | (void) atomicio(vwrite, sock_out, s, strlen(s)); |
3c0ef626 | 488 | close(sock_in); |
489 | close(sock_out); | |
70791e56 | 490 | logit("Protocol major versions differ for %s: %.200s vs. %.200s", |
3c0ef626 | 491 | get_remote_ipaddr(), |
492 | server_version_string, client_version_string); | |
416fd2a8 | 493 | cleanup_exit(255); |
3c0ef626 | 494 | } |
495 | } | |
496 | ||
3c0ef626 | 497 | /* Destroy the host and server keys. They will no longer be needed. */ |
498 | void | |
499 | destroy_sensitive_data(void) | |
500 | { | |
501 | int i; | |
502 | ||
503 | if (sensitive_data.server_key) { | |
504 | key_free(sensitive_data.server_key); | |
505 | sensitive_data.server_key = NULL; | |
506 | } | |
1e608e42 | 507 | for (i = 0; i < options.num_host_key_files; i++) { |
3c0ef626 | 508 | if (sensitive_data.host_keys[i]) { |
509 | key_free(sensitive_data.host_keys[i]); | |
510 | sensitive_data.host_keys[i] = NULL; | |
511 | } | |
512 | } | |
513 | sensitive_data.ssh1_host_key = NULL; | |
514 | memset(sensitive_data.ssh1_cookie, 0, SSH_SESSION_KEY_LENGTH); | |
515 | } | |
516 | ||
2980ea68 | 517 | /* Demote private to public keys for network child */ |
518 | void | |
519 | demote_sensitive_data(void) | |
520 | { | |
521 | Key *tmp; | |
522 | int i; | |
523 | ||
524 | if (sensitive_data.server_key) { | |
525 | tmp = key_demote(sensitive_data.server_key); | |
526 | key_free(sensitive_data.server_key); | |
527 | sensitive_data.server_key = tmp; | |
528 | } | |
529 | ||
530 | for (i = 0; i < options.num_host_key_files; i++) { | |
531 | if (sensitive_data.host_keys[i]) { | |
532 | tmp = key_demote(sensitive_data.host_keys[i]); | |
533 | key_free(sensitive_data.host_keys[i]); | |
534 | sensitive_data.host_keys[i] = tmp; | |
535 | if (tmp->type == KEY_RSA1) | |
536 | sensitive_data.ssh1_host_key = tmp; | |
537 | } | |
538 | } | |
539 | ||
540 | /* We do not clear ssh1_host key and cookie. XXX - Okay Niels? */ | |
541 | } | |
542 | ||
543 | static void | |
544 | privsep_preauth_child(void) | |
545 | { | |
e54b3d7c | 546 | u_int32_t rnd[256]; |
547 | gid_t gidset[1]; | |
2980ea68 | 548 | struct passwd *pw; |
ff2d7a98 | 549 | int i; |
2980ea68 | 550 | |
551 | /* Enable challenge-response authentication for privilege separation */ | |
552 | privsep_challenge_enable(); | |
553 | ||
554 | for (i = 0; i < 256; i++) | |
e54b3d7c | 555 | rnd[i] = arc4random(); |
556 | RAND_seed(rnd, sizeof(rnd)); | |
2980ea68 | 557 | |
558 | /* Demote the private keys to public keys. */ | |
559 | demote_sensitive_data(); | |
560 | ||
561 | if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) | |
562 | fatal("Privilege separation user %s does not exist", | |
563 | SSH_PRIVSEP_USER); | |
564 | memset(pw->pw_passwd, 0, strlen(pw->pw_passwd)); | |
565 | endpwent(); | |
566 | ||
e54b3d7c | 567 | /* Change our root directory */ |
2980ea68 | 568 | if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1) |
569 | fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR, | |
570 | strerror(errno)); | |
571 | if (chdir("/") == -1) | |
572 | fatal("chdir(\"/\"): %s", strerror(errno)); | |
573 | ||
574 | /* Drop our privileges */ | |
575 | debug3("privsep user:group %u:%u", (u_int)pw->pw_uid, | |
576 | (u_int)pw->pw_gid); | |
ff2d7a98 | 577 | #if 0 |
2a304a95 | 578 | /* XXX not ready, too heavy after chroot */ |
2980ea68 | 579 | do_setusercontext(pw); |
ff2d7a98 | 580 | #else |
581 | gidset[0] = pw->pw_gid; | |
ff2d7a98 | 582 | if (setgroups(1, gidset) < 0) |
583 | fatal("setgroups: %.100s", strerror(errno)); | |
584 | permanently_set_uid(pw); | |
585 | #endif | |
2980ea68 | 586 | } |
587 | ||
416fd2a8 | 588 | static int |
589 | privsep_preauth(Authctxt *authctxt) | |
2980ea68 | 590 | { |
2980ea68 | 591 | int status; |
592 | pid_t pid; | |
593 | ||
594 | /* Set up unprivileged child process to deal with network data */ | |
595 | pmonitor = monitor_init(); | |
596 | /* Store a pointer to the kex for later rekeying */ | |
597 | pmonitor->m_pkex = &xxx_kex; | |
598 | ||
599 | pid = fork(); | |
600 | if (pid == -1) { | |
601 | fatal("fork of unprivileged child failed"); | |
602 | } else if (pid != 0) { | |
ff2d7a98 | 603 | debug2("Network child is on pid %ld", (long)pid); |
2980ea68 | 604 | |
605 | close(pmonitor->m_recvfd); | |
416fd2a8 | 606 | pmonitor->m_pid = pid; |
607 | monitor_child_preauth(authctxt, pmonitor); | |
2980ea68 | 608 | close(pmonitor->m_sendfd); |
609 | ||
610 | /* Sync memory */ | |
611 | monitor_sync(pmonitor); | |
612 | ||
613 | /* Wait for the child's exit status */ | |
614 | while (waitpid(pid, &status, 0) < 0) | |
615 | if (errno != EINTR) | |
616 | break; | |
416fd2a8 | 617 | return (1); |
2980ea68 | 618 | } else { |
619 | /* child */ | |
620 | ||
621 | close(pmonitor->m_sendfd); | |
622 | ||
623 | /* Demote the child */ | |
624 | if (getuid() == 0 || geteuid() == 0) | |
625 | privsep_preauth_child(); | |
626 | setproctitle("%s", "[net]"); | |
627 | } | |
416fd2a8 | 628 | return (0); |
2980ea68 | 629 | } |
630 | ||
631 | static void | |
632 | privsep_postauth(Authctxt *authctxt) | |
633 | { | |
e54b3d7c | 634 | #ifdef DISABLE_FD_PASSING |
ff2d7a98 | 635 | if (1) { |
636 | #else | |
2980ea68 | 637 | if (authctxt->pw->pw_uid == 0 || options.use_login) { |
ff2d7a98 | 638 | #endif |
2980ea68 | 639 | /* File descriptor passing is broken or root login */ |
2980ea68 | 640 | use_privsep = 0; |
e00da40d | 641 | goto skip; |
2980ea68 | 642 | } |
643 | ||
644 | /* New socket pair */ | |
645 | monitor_reinit(pmonitor); | |
646 | ||
647 | pmonitor->m_pid = fork(); | |
648 | if (pmonitor->m_pid == -1) | |
649 | fatal("fork of unprivileged child failed"); | |
650 | else if (pmonitor->m_pid != 0) { | |
ff2d7a98 | 651 | debug2("User child is on pid %ld", (long)pmonitor->m_pid); |
2980ea68 | 652 | close(pmonitor->m_recvfd); |
1b56ff3d | 653 | buffer_clear(&loginmsg); |
2980ea68 | 654 | monitor_child_postauth(pmonitor); |
655 | ||
656 | /* NEVERREACHED */ | |
657 | exit(0); | |
658 | } | |
659 | ||
660 | close(pmonitor->m_sendfd); | |
661 | ||
662 | /* Demote the private keys to public keys. */ | |
663 | demote_sensitive_data(); | |
664 | ||
665 | /* Drop privileges */ | |
666 | do_setusercontext(authctxt->pw); | |
667 | ||
e00da40d | 668 | skip: |
2980ea68 | 669 | /* It is safe now to apply the key state */ |
670 | monitor_apply_keystate(pmonitor); | |
34fee935 | 671 | |
672 | /* | |
673 | * Tell the packet layer that authentication was successful, since | |
674 | * this information is not part of the key state. | |
675 | */ | |
676 | packet_set_authenticated(); | |
2980ea68 | 677 | } |
678 | ||
3c0ef626 | 679 | static char * |
680 | list_hostkey_types(void) | |
681 | { | |
1e608e42 | 682 | Buffer b; |
416fd2a8 | 683 | const char *p; |
684 | char *ret; | |
3c0ef626 | 685 | int i; |
1e608e42 | 686 | |
687 | buffer_init(&b); | |
688 | for (i = 0; i < options.num_host_key_files; i++) { | |
3c0ef626 | 689 | Key *key = sensitive_data.host_keys[i]; |
690 | if (key == NULL) | |
691 | continue; | |
1e608e42 | 692 | switch (key->type) { |
3c0ef626 | 693 | case KEY_RSA: |
694 | case KEY_DSA: | |
1e608e42 | 695 | if (buffer_len(&b) > 0) |
696 | buffer_append(&b, ",", 1); | |
697 | p = key_ssh_name(key); | |
698 | buffer_append(&b, p, strlen(p)); | |
3c0ef626 | 699 | break; |
700 | } | |
701 | } | |
1e608e42 | 702 | buffer_append(&b, "\0", 1); |
416fd2a8 | 703 | ret = xstrdup(buffer_ptr(&b)); |
1e608e42 | 704 | buffer_free(&b); |
416fd2a8 | 705 | debug("list_hostkey_types: %s", ret); |
706 | return ret; | |
3c0ef626 | 707 | } |
708 | ||
2980ea68 | 709 | Key * |
3c0ef626 | 710 | get_hostkey_by_type(int type) |
711 | { | |
712 | int i; | |
ff2d7a98 | 713 | |
1e608e42 | 714 | for (i = 0; i < options.num_host_key_files; i++) { |
3c0ef626 | 715 | Key *key = sensitive_data.host_keys[i]; |
716 | if (key != NULL && key->type == type) | |
717 | return key; | |
718 | } | |
719 | return NULL; | |
720 | } | |
721 | ||
2980ea68 | 722 | Key * |
723 | get_hostkey_by_index(int ind) | |
724 | { | |
725 | if (ind < 0 || ind >= options.num_host_key_files) | |
726 | return (NULL); | |
727 | return (sensitive_data.host_keys[ind]); | |
728 | } | |
729 | ||
730 | int | |
731 | get_hostkey_index(Key *key) | |
732 | { | |
733 | int i; | |
ff2d7a98 | 734 | |
2980ea68 | 735 | for (i = 0; i < options.num_host_key_files; i++) { |
736 | if (key == sensitive_data.host_keys[i]) | |
737 | return (i); | |
738 | } | |
739 | return (-1); | |
740 | } | |
741 | ||
3c0ef626 | 742 | /* |
743 | * returns 1 if connection should be dropped, 0 otherwise. | |
744 | * dropping starts at connection #max_startups_begin with a probability | |
745 | * of (max_startups_rate/100). the probability increases linearly until | |
746 | * all connections are dropped for startups > max_startups | |
747 | */ | |
748 | static int | |
749 | drop_connection(int startups) | |
750 | { | |
34fee935 | 751 | int p, r; |
3c0ef626 | 752 | |
753 | if (startups < options.max_startups_begin) | |
754 | return 0; | |
755 | if (startups >= options.max_startups) | |
756 | return 1; | |
757 | if (options.max_startups_rate == 100) | |
758 | return 1; | |
759 | ||
760 | p = 100 - options.max_startups_rate; | |
761 | p *= startups - options.max_startups_begin; | |
34fee935 | 762 | p /= options.max_startups - options.max_startups_begin; |
3c0ef626 | 763 | p += options.max_startups_rate; |
34fee935 | 764 | r = arc4random() % 100; |
3c0ef626 | 765 | |
34fee935 | 766 | debug("drop_connection: p %d, r %d", p, r); |
3c0ef626 | 767 | return (r < p) ? 1 : 0; |
768 | } | |
769 | ||
1e608e42 | 770 | static void |
771 | usage(void) | |
772 | { | |
2a304a95 | 773 | fprintf(stderr, "%s, %s\n", |
34fee935 | 774 | SSH_RELEASE, SSLeay_version(SSLEAY_VERSION)); |
2a304a95 | 775 | fprintf(stderr, |
776 | "usage: sshd [-46Ddeiqt] [-b bits] [-f config_file] [-g login_grace_time]\n" | |
777 | " [-h host_key_file] [-k key_gen_time] [-o option] [-p port] [-u len]\n" | |
778 | ); | |
1e608e42 | 779 | exit(1); |
780 | } | |
3c0ef626 | 781 | |
1b56ff3d | 782 | static void |
783 | send_rexec_state(int fd, Buffer *conf) | |
784 | { | |
785 | Buffer m; | |
786 | ||
787 | debug3("%s: entering fd = %d config len %d", __func__, fd, | |
788 | buffer_len(conf)); | |
789 | ||
790 | /* | |
791 | * Protocol from reexec master to child: | |
792 | * string configuration | |
793 | * u_int ephemeral_key_follows | |
794 | * bignum e (only if ephemeral_key_follows == 1) | |
795 | * bignum n " | |
796 | * bignum d " | |
797 | * bignum iqmp " | |
798 | * bignum p " | |
799 | * bignum q " | |
e00da40d | 800 | * string rngseed (only if OpenSSL is not self-seeded) |
1b56ff3d | 801 | */ |
802 | buffer_init(&m); | |
803 | buffer_put_cstring(&m, buffer_ptr(conf)); | |
804 | ||
805 | if (sensitive_data.server_key != NULL && | |
806 | sensitive_data.server_key->type == KEY_RSA1) { | |
807 | buffer_put_int(&m, 1); | |
808 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->e); | |
809 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->n); | |
810 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->d); | |
811 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->iqmp); | |
812 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->p); | |
813 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->q); | |
814 | } else | |
815 | buffer_put_int(&m, 0); | |
816 | ||
e00da40d | 817 | #ifndef OPENSSL_PRNG_ONLY |
818 | rexec_send_rng_seed(&m); | |
819 | #endif | |
820 | ||
1b56ff3d | 821 | if (ssh_msg_send(fd, 0, &m) == -1) |
822 | fatal("%s: ssh_msg_send failed", __func__); | |
823 | ||
824 | buffer_free(&m); | |
825 | ||
826 | debug3("%s: done", __func__); | |
827 | } | |
828 | ||
829 | static void | |
830 | recv_rexec_state(int fd, Buffer *conf) | |
831 | { | |
832 | Buffer m; | |
833 | char *cp; | |
834 | u_int len; | |
835 | ||
836 | debug3("%s: entering fd = %d", __func__, fd); | |
837 | ||
838 | buffer_init(&m); | |
839 | ||
840 | if (ssh_msg_recv(fd, &m) == -1) | |
841 | fatal("%s: ssh_msg_recv failed", __func__); | |
842 | if (buffer_get_char(&m) != 0) | |
843 | fatal("%s: rexec version mismatch", __func__); | |
844 | ||
845 | cp = buffer_get_string(&m, &len); | |
846 | if (conf != NULL) | |
847 | buffer_append(conf, cp, len + 1); | |
848 | xfree(cp); | |
849 | ||
850 | if (buffer_get_int(&m)) { | |
851 | if (sensitive_data.server_key != NULL) | |
852 | key_free(sensitive_data.server_key); | |
853 | sensitive_data.server_key = key_new_private(KEY_RSA1); | |
854 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->e); | |
855 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->n); | |
856 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->d); | |
857 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->iqmp); | |
858 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->p); | |
859 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->q); | |
860 | rsa_generate_additional_parameters( | |
861 | sensitive_data.server_key->rsa); | |
862 | } | |
e00da40d | 863 | |
864 | #ifndef OPENSSL_PRNG_ONLY | |
865 | rexec_recv_rng_seed(&m); | |
866 | #endif | |
867 | ||
1b56ff3d | 868 | buffer_free(&m); |
869 | ||
870 | debug3("%s: done", __func__); | |
871 | } | |
872 | ||
3c0ef626 | 873 | /* |
874 | * Main program for the daemon. | |
875 | */ | |
876 | int | |
877 | main(int ac, char **av) | |
878 | { | |
879 | extern char *optarg; | |
880 | extern int optind; | |
1b56ff3d | 881 | int opt, j, i, fdsetsz, on = 1; |
882 | int sock_in = -1, sock_out = -1, newsock = -1; | |
3c0ef626 | 883 | pid_t pid; |
884 | socklen_t fromlen; | |
885 | fd_set *fdset; | |
886 | struct sockaddr_storage from; | |
887 | const char *remote_ip; | |
888 | int remote_port; | |
889 | FILE *f; | |
3c0ef626 | 890 | struct addrinfo *ai; |
891 | char ntop[NI_MAXHOST], strport[NI_MAXSERV]; | |
416fd2a8 | 892 | char *line; |
3c0ef626 | 893 | int listen_sock, maxfd; |
34fee935 | 894 | int startup_p[2] = { -1 , -1 }, config_s[2] = { -1 , -1 }; |
3c0ef626 | 895 | int startups = 0; |
896 | Key *key; | |
416fd2a8 | 897 | Authctxt *authctxt; |
3c0ef626 | 898 | int ret, key_used = 0; |
1b56ff3d | 899 | Buffer cfg; |
3c0ef626 | 900 | |
2980ea68 | 901 | #ifdef HAVE_SECUREWARE |
902 | (void)set_auth_parameters(ac, av); | |
903 | #endif | |
70791e56 | 904 | __progname = ssh_get_progname(av[0]); |
ae43c103 | 905 | init_pathnames(); |
004706ea | 906 | config_file_name = _PATH_SERVER_CONFIG_FILE; |
3c0ef626 | 907 | init_rng(); |
908 | ||
1c14df9e | 909 | /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */ |
3c0ef626 | 910 | saved_argc = ac; |
1b56ff3d | 911 | rexec_argc = ac; |
70791e56 | 912 | saved_argv = xmalloc(sizeof(*saved_argv) * (ac + 1)); |
1c14df9e | 913 | for (i = 0; i < ac; i++) |
914 | saved_argv[i] = xstrdup(av[i]); | |
70791e56 | 915 | saved_argv[i] = NULL; |
1c14df9e | 916 | |
917 | #ifndef HAVE_SETPROCTITLE | |
918 | /* Prepare for later setproctitle emulation */ | |
919 | compat_init_setproctitle(ac, av); | |
70791e56 | 920 | av = saved_argv; |
1c14df9e | 921 | #endif |
3c0ef626 | 922 | |
2a304a95 | 923 | if (geteuid() == 0 && setgroups(0, NULL) == -1) |
924 | debug("setgroups(): %.200s", strerror(errno)); | |
925 | ||
e00da40d | 926 | /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ |
927 | sanitise_stdfd(); | |
928 | ||
3c0ef626 | 929 | /* Initialize configuration options to their default values. */ |
930 | initialize_server_options(&options); | |
931 | ||
932 | /* Parse command-line arguments. */ | |
1b56ff3d | 933 | while ((opt = getopt(ac, av, "f:p:b:k:h:g:u:o:dDeiqrtQR46")) != -1) { |
3c0ef626 | 934 | switch (opt) { |
935 | case '4': | |
34fee935 | 936 | options.address_family = AF_INET; |
3c0ef626 | 937 | break; |
938 | case '6': | |
34fee935 | 939 | options.address_family = AF_INET6; |
3c0ef626 | 940 | break; |
941 | case 'f': | |
942 | config_file_name = optarg; | |
943 | break; | |
944 | case 'd': | |
70791e56 | 945 | if (debug_flag == 0) { |
3c0ef626 | 946 | debug_flag = 1; |
947 | options.log_level = SYSLOG_LEVEL_DEBUG1; | |
70791e56 | 948 | } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) |
3c0ef626 | 949 | options.log_level++; |
3c0ef626 | 950 | break; |
951 | case 'D': | |
952 | no_daemon_flag = 1; | |
953 | break; | |
954 | case 'e': | |
955 | log_stderr = 1; | |
956 | break; | |
957 | case 'i': | |
958 | inetd_flag = 1; | |
959 | break; | |
1b56ff3d | 960 | case 'r': |
961 | rexec_flag = 0; | |
962 | break; | |
963 | case 'R': | |
964 | rexeced_flag = 1; | |
965 | inetd_flag = 1; | |
966 | break; | |
3c0ef626 | 967 | case 'Q': |
968 | /* ignored */ | |
969 | break; | |
970 | case 'q': | |
971 | options.log_level = SYSLOG_LEVEL_QUIET; | |
972 | break; | |
973 | case 'b': | |
974 | options.server_key_bits = atoi(optarg); | |
975 | break; | |
976 | case 'p': | |
977 | options.ports_from_cmdline = 1; | |
978 | if (options.num_ports >= MAX_PORTS) { | |
979 | fprintf(stderr, "too many ports.\n"); | |
980 | exit(1); | |
981 | } | |
982 | options.ports[options.num_ports++] = a2port(optarg); | |
983 | if (options.ports[options.num_ports-1] == 0) { | |
984 | fprintf(stderr, "Bad port number.\n"); | |
985 | exit(1); | |
986 | } | |
987 | break; | |
988 | case 'g': | |
989 | if ((options.login_grace_time = convtime(optarg)) == -1) { | |
990 | fprintf(stderr, "Invalid login grace time.\n"); | |
991 | exit(1); | |
992 | } | |
993 | break; | |
994 | case 'k': | |
995 | if ((options.key_regeneration_time = convtime(optarg)) == -1) { | |
996 | fprintf(stderr, "Invalid key regeneration interval.\n"); | |
997 | exit(1); | |
998 | } | |
999 | break; | |
1000 | case 'h': | |
1001 | if (options.num_host_key_files >= MAX_HOSTKEYS) { | |
1002 | fprintf(stderr, "too many host keys.\n"); | |
1003 | exit(1); | |
1004 | } | |
1005 | options.host_key_files[options.num_host_key_files++] = optarg; | |
1006 | break; | |
3c0ef626 | 1007 | case 't': |
1008 | test_flag = 1; | |
1009 | break; | |
1010 | case 'u': | |
1011 | utmp_len = atoi(optarg); | |
e54b3d7c | 1012 | if (utmp_len > MAXHOSTNAMELEN) { |
1013 | fprintf(stderr, "Invalid utmp length.\n"); | |
1014 | exit(1); | |
1015 | } | |
3c0ef626 | 1016 | break; |
1e608e42 | 1017 | case 'o': |
416fd2a8 | 1018 | line = xstrdup(optarg); |
1019 | if (process_server_config_line(&options, line, | |
1e608e42 | 1020 | "command-line", 0) != 0) |
1021 | exit(1); | |
416fd2a8 | 1022 | xfree(line); |
1e608e42 | 1023 | break; |
3c0ef626 | 1024 | case '?': |
1025 | default: | |
1e608e42 | 1026 | usage(); |
1027 | break; | |
3c0ef626 | 1028 | } |
1029 | } | |
1b56ff3d | 1030 | if (rexeced_flag || inetd_flag) |
1031 | rexec_flag = 0; | |
1032 | if (rexec_flag && (av[0] == NULL || *av[0] != '/')) | |
1033 | fatal("sshd re-exec requires execution with an absolute path"); | |
1034 | if (rexeced_flag) | |
1035 | closefrom(REEXEC_MIN_FREE_FD); | |
1036 | else | |
1037 | closefrom(REEXEC_DEVCRYPTO_RESERVED_FD); | |
1038 | ||
3c0ef626 | 1039 | SSLeay_add_all_algorithms(); |
3c0ef626 | 1040 | |
1041 | /* | |
1042 | * Force logging to stderr until we have loaded the private host | |
1043 | * key (unless started from inetd) | |
1044 | */ | |
1045 | log_init(__progname, | |
1e608e42 | 1046 | options.log_level == SYSLOG_LEVEL_NOT_SET ? |
1047 | SYSLOG_LEVEL_INFO : options.log_level, | |
1048 | options.log_facility == SYSLOG_FACILITY_NOT_SET ? | |
1049 | SYSLOG_FACILITY_AUTH : options.log_facility, | |
1c14df9e | 1050 | log_stderr || !inetd_flag); |
3c0ef626 | 1051 | |
2a304a95 | 1052 | /* |
1053 | * Unset KRB5CCNAME, otherwise the user's session may inherit it from | |
1054 | * root's environment | |
34fee935 | 1055 | */ |
1056 | if (getenv("KRB5CCNAME") != NULL) | |
1057 | unsetenv("KRB5CCNAME"); | |
1058 | ||
e54b3d7c | 1059 | #ifdef _UNICOS |
1b56ff3d | 1060 | /* Cray can define user privs drop all privs now! |
3c0ef626 | 1061 | * Not needed on PRIV_SU systems! |
1062 | */ | |
1063 | drop_cray_privs(); | |
1064 | #endif | |
1065 | ||
1b56ff3d | 1066 | sensitive_data.server_key = NULL; |
1067 | sensitive_data.ssh1_host_key = NULL; | |
1068 | sensitive_data.have_ssh1_key = 0; | |
1069 | sensitive_data.have_ssh2_key = 0; | |
1070 | ||
1071 | /* Fetch our configuration */ | |
1072 | buffer_init(&cfg); | |
1073 | if (rexeced_flag) | |
1074 | recv_rexec_state(REEXEC_CONFIG_PASS_FD, &cfg); | |
1075 | else | |
1076 | load_server_config(config_file_name, &cfg); | |
1077 | ||
1078 | parse_server_config(&options, | |
1079 | rexeced_flag ? "rexec" : config_file_name, &cfg); | |
1080 | ||
1081 | if (!rexec_flag) | |
1082 | buffer_free(&cfg); | |
3c0ef626 | 1083 | |
e00da40d | 1084 | seed_rng(); |
1085 | ||
3c0ef626 | 1086 | /* Fill in default values for those options not explicitly set. */ |
1087 | fill_default_server_options(&options); | |
1088 | ||
34fee935 | 1089 | /* set default channel AF */ |
1090 | channel_set_af(options.address_family); | |
1091 | ||
3c0ef626 | 1092 | /* Check that there are no remaining arguments. */ |
1093 | if (optind < ac) { | |
1094 | fprintf(stderr, "Extra argument %s.\n", av[optind]); | |
1095 | exit(1); | |
1096 | } | |
1097 | ||
34fee935 | 1098 | debug("sshd version %.100s", SSH_RELEASE); |
3c0ef626 | 1099 | |
1100 | /* load private host keys */ | |
e54b3d7c | 1101 | sensitive_data.host_keys = xmalloc(options.num_host_key_files * |
1102 | sizeof(Key *)); | |
1e608e42 | 1103 | for (i = 0; i < options.num_host_key_files; i++) |
3c0ef626 | 1104 | sensitive_data.host_keys[i] = NULL; |
3c0ef626 | 1105 | |
1e608e42 | 1106 | for (i = 0; i < options.num_host_key_files; i++) { |
3c0ef626 | 1107 | key = key_load_private(options.host_key_files[i], "", NULL); |
1108 | sensitive_data.host_keys[i] = key; | |
1109 | if (key == NULL) { | |
1110 | error("Could not load host key: %s", | |
1111 | options.host_key_files[i]); | |
1112 | sensitive_data.host_keys[i] = NULL; | |
1113 | continue; | |
1114 | } | |
1e608e42 | 1115 | switch (key->type) { |
3c0ef626 | 1116 | case KEY_RSA1: |
1117 | sensitive_data.ssh1_host_key = key; | |
1118 | sensitive_data.have_ssh1_key = 1; | |
1119 | break; | |
1120 | case KEY_RSA: | |
1121 | case KEY_DSA: | |
1122 | sensitive_data.have_ssh2_key = 1; | |
1123 | break; | |
1124 | } | |
1125 | debug("private host key: #%d type %d %s", i, key->type, | |
1126 | key_type(key)); | |
1127 | } | |
1128 | if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) { | |
70791e56 | 1129 | logit("Disabling protocol version 1. Could not load host key"); |
3c0ef626 | 1130 | options.protocol &= ~SSH_PROTO_1; |
1131 | } | |
5598e598 | 1132 | #ifndef GSSAPI |
1133 | /* The GSSAPI key exchange can run without a host key */ | |
3c0ef626 | 1134 | if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) { |
70791e56 | 1135 | logit("Disabling protocol version 2. Could not load host key"); |
3c0ef626 | 1136 | options.protocol &= ~SSH_PROTO_2; |
1137 | } | |
5598e598 | 1138 | #endif |
3c0ef626 | 1139 | if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) { |
70791e56 | 1140 | logit("sshd: no hostkeys available -- exiting."); |
3c0ef626 | 1141 | exit(1); |
1142 | } | |
1143 | ||
1144 | /* Check certain values for sanity. */ | |
1145 | if (options.protocol & SSH_PROTO_1) { | |
1146 | if (options.server_key_bits < 512 || | |
1147 | options.server_key_bits > 32768) { | |
1148 | fprintf(stderr, "Bad server key size.\n"); | |
1149 | exit(1); | |
1150 | } | |
1151 | /* | |
1152 | * Check that server and host key lengths differ sufficiently. This | |
1153 | * is necessary to make double encryption work with rsaref. Oh, I | |
1154 | * hate software patents. I dont know if this can go? Niels | |
1155 | */ | |
1156 | if (options.server_key_bits > | |
ff2d7a98 | 1157 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) - |
1158 | SSH_KEY_BITS_RESERVED && options.server_key_bits < | |
1159 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + | |
1160 | SSH_KEY_BITS_RESERVED) { | |
3c0ef626 | 1161 | options.server_key_bits = |
ff2d7a98 | 1162 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + |
1163 | SSH_KEY_BITS_RESERVED; | |
3c0ef626 | 1164 | debug("Forcing server key to %d bits to make it differ from host key.", |
1165 | options.server_key_bits); | |
1166 | } | |
1167 | } | |
1168 | ||
ff2d7a98 | 1169 | if (use_privsep) { |
1170 | struct passwd *pw; | |
1171 | struct stat st; | |
1172 | ||
1173 | if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) | |
1174 | fatal("Privilege separation user %s does not exist", | |
1175 | SSH_PRIVSEP_USER); | |
1176 | if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) || | |
1177 | (S_ISDIR(st.st_mode) == 0)) | |
1178 | fatal("Missing privilege separation directory: %s", | |
1179 | _PATH_PRIVSEP_CHROOT_DIR); | |
e54b3d7c | 1180 | |
1181 | #ifdef HAVE_CYGWIN | |
1182 | if (check_ntsec(_PATH_PRIVSEP_CHROOT_DIR) && | |
1183 | (st.st_uid != getuid () || | |
1184 | (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)) | |
1185 | #else | |
ff2d7a98 | 1186 | if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0) |
e54b3d7c | 1187 | #endif |
1c14df9e | 1188 | fatal("%s must be owned by root and not group or " |
1189 | "world-writable.", _PATH_PRIVSEP_CHROOT_DIR); | |
ff2d7a98 | 1190 | } |
1191 | ||
3c0ef626 | 1192 | /* Configuration looks good, so exit if in test mode. */ |
1193 | if (test_flag) | |
1194 | exit(0); | |
1195 | ||
2980ea68 | 1196 | /* |
1197 | * Clear out any supplemental groups we may have inherited. This | |
1198 | * prevents inadvertent creation of files with bad modes (in the | |
416fd2a8 | 1199 | * portable version at least, it's certainly possible for PAM |
1200 | * to create a file, and we can't control the code in every | |
2980ea68 | 1201 | * module which might be used). |
1202 | */ | |
1203 | if (setgroups(0, NULL) < 0) | |
1204 | debug("setgroups() failed: %.200s", strerror(errno)); | |
3c0ef626 | 1205 | |
1b56ff3d | 1206 | if (rexec_flag) { |
1207 | rexec_argv = xmalloc(sizeof(char *) * (rexec_argc + 2)); | |
1208 | for (i = 0; i < rexec_argc; i++) { | |
1209 | debug("rexec_argv[%d]='%s'", i, saved_argv[i]); | |
1210 | rexec_argv[i] = saved_argv[i]; | |
1211 | } | |
1212 | rexec_argv[rexec_argc] = "-R"; | |
1213 | rexec_argv[rexec_argc + 1] = NULL; | |
1214 | } | |
1215 | ||
3c0ef626 | 1216 | /* Initialize the log (it is reinitialized below in case we forked). */ |
34fee935 | 1217 | if (debug_flag && (!inetd_flag || rexeced_flag)) |
3c0ef626 | 1218 | log_stderr = 1; |
1219 | log_init(__progname, options.log_level, options.log_facility, log_stderr); | |
1220 | ||
1221 | /* | |
1222 | * If not in debugging mode, and not started from inetd, disconnect | |
1223 | * from the controlling terminal, and fork. The original process | |
1224 | * exits. | |
1225 | */ | |
1226 | if (!(debug_flag || inetd_flag || no_daemon_flag)) { | |
1227 | #ifdef TIOCNOTTY | |
1228 | int fd; | |
1229 | #endif /* TIOCNOTTY */ | |
1230 | if (daemon(0, 0) < 0) | |
1231 | fatal("daemon() failed: %.200s", strerror(errno)); | |
1232 | ||
1233 | /* Disconnect from the controlling tty. */ | |
1234 | #ifdef TIOCNOTTY | |
1235 | fd = open(_PATH_TTY, O_RDWR | O_NOCTTY); | |
1236 | if (fd >= 0) { | |
1237 | (void) ioctl(fd, TIOCNOTTY, NULL); | |
1238 | close(fd); | |
1239 | } | |
1240 | #endif /* TIOCNOTTY */ | |
1241 | } | |
1242 | /* Reinitialize the log (because of the fork above). */ | |
1243 | log_init(__progname, options.log_level, options.log_facility, log_stderr); | |
1244 | ||
1245 | /* Initialize the random number generator. */ | |
1246 | arc4random_stir(); | |
1247 | ||
1248 | /* Chdir to the root directory so that the current disk can be | |
1249 | unmounted if desired. */ | |
1250 | chdir("/"); | |
1e608e42 | 1251 | |
3c0ef626 | 1252 | /* ignore SIGPIPE */ |
1253 | signal(SIGPIPE, SIG_IGN); | |
1254 | ||
1255 | /* Start listening for a socket, unless started from inetd. */ | |
1256 | if (inetd_flag) { | |
1b56ff3d | 1257 | int fd; |
1258 | ||
3c0ef626 | 1259 | startup_pipe = -1; |
1b56ff3d | 1260 | if (rexeced_flag) { |
1261 | close(REEXEC_CONFIG_PASS_FD); | |
1262 | sock_in = sock_out = dup(STDIN_FILENO); | |
1263 | if (!debug_flag) { | |
1264 | startup_pipe = dup(REEXEC_STARTUP_PIPE_FD); | |
1265 | close(REEXEC_STARTUP_PIPE_FD); | |
1266 | } | |
1267 | } else { | |
1268 | sock_in = dup(STDIN_FILENO); | |
1269 | sock_out = dup(STDOUT_FILENO); | |
1270 | } | |
3c0ef626 | 1271 | /* |
1272 | * We intentionally do not close the descriptors 0, 1, and 2 | |
1b56ff3d | 1273 | * as our code for setting the descriptors won't work if |
3c0ef626 | 1274 | * ttyfd happens to be one of those. |
1275 | */ | |
1b56ff3d | 1276 | if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { |
1277 | dup2(fd, STDIN_FILENO); | |
1278 | dup2(fd, STDOUT_FILENO); | |
1279 | if (fd > STDOUT_FILENO) | |
1280 | close(fd); | |
1281 | } | |
3c0ef626 | 1282 | debug("inetd sockets after dupping: %d, %d", sock_in, sock_out); |
1b56ff3d | 1283 | if ((options.protocol & SSH_PROTO_1) && |
1284 | sensitive_data.server_key == NULL) | |
3c0ef626 | 1285 | generate_ephemeral_server_key(); |
1286 | } else { | |
1287 | for (ai = options.listen_addrs; ai; ai = ai->ai_next) { | |
1288 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) | |
1289 | continue; | |
1290 | if (num_listen_socks >= MAX_LISTEN_SOCKS) | |
1291 | fatal("Too many listen sockets. " | |
1292 | "Enlarge MAX_LISTEN_SOCKS"); | |
34fee935 | 1293 | if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen, |
3c0ef626 | 1294 | ntop, sizeof(ntop), strport, sizeof(strport), |
34fee935 | 1295 | NI_NUMERICHOST|NI_NUMERICSERV)) != 0) { |
1296 | error("getnameinfo failed: %.100s", | |
1297 | (ret != EAI_SYSTEM) ? gai_strerror(ret) : | |
1298 | strerror(errno)); | |
3c0ef626 | 1299 | continue; |
1300 | } | |
1301 | /* Create socket for listening. */ | |
70791e56 | 1302 | listen_sock = socket(ai->ai_family, ai->ai_socktype, |
1303 | ai->ai_protocol); | |
3c0ef626 | 1304 | if (listen_sock < 0) { |
1305 | /* kernel may not support ipv6 */ | |
1306 | verbose("socket: %.100s", strerror(errno)); | |
1307 | continue; | |
1308 | } | |
1b56ff3d | 1309 | if (set_nonblock(listen_sock) == -1) { |
3c0ef626 | 1310 | close(listen_sock); |
1311 | continue; | |
1312 | } | |
1313 | /* | |
e54b3d7c | 1314 | * Set socket options. |
1315 | * Allow local port reuse in TIME_WAIT. | |
3c0ef626 | 1316 | */ |
e54b3d7c | 1317 | if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR, |
1318 | &on, sizeof(on)) == -1) | |
1319 | error("setsockopt SO_REUSEADDR: %s", strerror(errno)); | |
3c0ef626 | 1320 | |
1321 | debug("Bind to port %s on %s.", strport, ntop); | |
1322 | ||
1323 | /* Bind the socket to the desired port. */ | |
1324 | if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) { | |
1325 | if (!ai->ai_next) | |
1326 | error("Bind to port %s on %s failed: %.200s.", | |
1327 | strport, ntop, strerror(errno)); | |
1328 | close(listen_sock); | |
1329 | continue; | |
1330 | } | |
1331 | listen_socks[num_listen_socks] = listen_sock; | |
1332 | num_listen_socks++; | |
1333 | ||
1334 | /* Start listening on the port. */ | |
70791e56 | 1335 | logit("Server listening on %s port %s.", ntop, strport); |
416fd2a8 | 1336 | if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0) |
3c0ef626 | 1337 | fatal("listen: %.100s", strerror(errno)); |
1338 | ||
1339 | } | |
1340 | freeaddrinfo(options.listen_addrs); | |
1341 | ||
1342 | if (!num_listen_socks) | |
1343 | fatal("Cannot bind any address."); | |
1344 | ||
1345 | if (options.protocol & SSH_PROTO_1) | |
1346 | generate_ephemeral_server_key(); | |
1347 | ||
1348 | /* | |
1349 | * Arrange to restart on SIGHUP. The handler needs | |
1350 | * listen_sock. | |
1351 | */ | |
1352 | signal(SIGHUP, sighup_handler); | |
1353 | ||
1354 | signal(SIGTERM, sigterm_handler); | |
1355 | signal(SIGQUIT, sigterm_handler); | |
1356 | ||
1357 | /* Arrange SIGCHLD to be caught. */ | |
1358 | signal(SIGCHLD, main_sigchld_handler); | |
1359 | ||
1360 | /* Write out the pid file after the sigterm handler is setup */ | |
1361 | if (!debug_flag) { | |
1362 | /* | |
1363 | * Record our pid in /var/run/sshd.pid to make it | |
1364 | * easier to kill the correct sshd. We don't want to | |
1365 | * do this before the bind above because the bind will | |
1366 | * fail if there already is a daemon, and this will | |
1367 | * overwrite any old pid in the file. | |
1368 | */ | |
1369 | f = fopen(options.pid_file, "wb"); | |
70791e56 | 1370 | if (f == NULL) { |
1371 | error("Couldn't create pid file \"%s\": %s", | |
1372 | options.pid_file, strerror(errno)); | |
1373 | } else { | |
ff2d7a98 | 1374 | fprintf(f, "%ld\n", (long) getpid()); |
3c0ef626 | 1375 | fclose(f); |
1376 | } | |
1377 | } | |
1378 | ||
1379 | /* setup fd set for listen */ | |
1380 | fdset = NULL; | |
1381 | maxfd = 0; | |
1382 | for (i = 0; i < num_listen_socks; i++) | |
1383 | if (listen_socks[i] > maxfd) | |
1384 | maxfd = listen_socks[i]; | |
1385 | /* pipes connected to unauthenticated childs */ | |
1386 | startup_pipes = xmalloc(options.max_startups * sizeof(int)); | |
1387 | for (i = 0; i < options.max_startups; i++) | |
1388 | startup_pipes[i] = -1; | |
1389 | ||
1390 | /* | |
1391 | * Stay listening for connections until the system crashes or | |
1392 | * the daemon is killed with a signal. | |
1393 | */ | |
1394 | for (;;) { | |
1395 | if (received_sighup) | |
1396 | sighup_restart(); | |
1397 | if (fdset != NULL) | |
1398 | xfree(fdset); | |
1399 | fdsetsz = howmany(maxfd+1, NFDBITS) * sizeof(fd_mask); | |
1400 | fdset = (fd_set *)xmalloc(fdsetsz); | |
1401 | memset(fdset, 0, fdsetsz); | |
1402 | ||
1403 | for (i = 0; i < num_listen_socks; i++) | |
1404 | FD_SET(listen_socks[i], fdset); | |
1405 | for (i = 0; i < options.max_startups; i++) | |
1406 | if (startup_pipes[i] != -1) | |
1407 | FD_SET(startup_pipes[i], fdset); | |
1408 | ||
1409 | /* Wait in select until there is a connection. */ | |
1410 | ret = select(maxfd+1, fdset, NULL, NULL, NULL); | |
1411 | if (ret < 0 && errno != EINTR) | |
1412 | error("select: %.100s", strerror(errno)); | |
1413 | if (received_sigterm) { | |
70791e56 | 1414 | logit("Received signal %d; terminating.", |
1e608e42 | 1415 | (int) received_sigterm); |
3c0ef626 | 1416 | close_listen_socks(); |
1417 | unlink(options.pid_file); | |
1418 | exit(255); | |
1419 | } | |
1420 | if (key_used && key_do_regen) { | |
1421 | generate_ephemeral_server_key(); | |
1422 | key_used = 0; | |
1423 | key_do_regen = 0; | |
1424 | } | |
1425 | if (ret < 0) | |
1426 | continue; | |
1427 | ||
1428 | for (i = 0; i < options.max_startups; i++) | |
1429 | if (startup_pipes[i] != -1 && | |
1430 | FD_ISSET(startup_pipes[i], fdset)) { | |
1431 | /* | |
1432 | * the read end of the pipe is ready | |
1433 | * if the child has closed the pipe | |
1434 | * after successful authentication | |
1435 | * or if the child has died | |
1436 | */ | |
1437 | close(startup_pipes[i]); | |
1438 | startup_pipes[i] = -1; | |
1439 | startups--; | |
1440 | } | |
1441 | for (i = 0; i < num_listen_socks; i++) { | |
1442 | if (!FD_ISSET(listen_socks[i], fdset)) | |
1443 | continue; | |
1444 | fromlen = sizeof(from); | |
1445 | newsock = accept(listen_socks[i], (struct sockaddr *)&from, | |
1446 | &fromlen); | |
1447 | if (newsock < 0) { | |
1448 | if (errno != EINTR && errno != EWOULDBLOCK) | |
1449 | error("accept: %.100s", strerror(errno)); | |
1450 | continue; | |
1451 | } | |
1b56ff3d | 1452 | if (unset_nonblock(newsock) == -1) { |
1e608e42 | 1453 | close(newsock); |
3c0ef626 | 1454 | continue; |
1455 | } | |
1456 | if (drop_connection(startups) == 1) { | |
1457 | debug("drop connection #%d", startups); | |
1458 | close(newsock); | |
1459 | continue; | |
1460 | } | |
1461 | if (pipe(startup_p) == -1) { | |
1462 | close(newsock); | |
1463 | continue; | |
1464 | } | |
1465 | ||
1b56ff3d | 1466 | if (rexec_flag && socketpair(AF_UNIX, |
1467 | SOCK_STREAM, 0, config_s) == -1) { | |
1468 | error("reexec socketpair: %s", | |
1469 | strerror(errno)); | |
1470 | close(newsock); | |
1471 | close(startup_p[0]); | |
1472 | close(startup_p[1]); | |
1473 | continue; | |
1474 | } | |
1475 | ||
3c0ef626 | 1476 | for (j = 0; j < options.max_startups; j++) |
1477 | if (startup_pipes[j] == -1) { | |
1478 | startup_pipes[j] = startup_p[0]; | |
1479 | if (maxfd < startup_p[0]) | |
1480 | maxfd = startup_p[0]; | |
1481 | startups++; | |
1482 | break; | |
1483 | } | |
1484 | ||
1485 | /* | |
1486 | * Got connection. Fork a child to handle it, unless | |
1487 | * we are in debugging mode. | |
1488 | */ | |
1489 | if (debug_flag) { | |
1490 | /* | |
1491 | * In debugging mode. Close the listening | |
1492 | * socket, and start processing the | |
1493 | * connection without forking. | |
1494 | */ | |
1495 | debug("Server will not fork when running in debugging mode."); | |
1496 | close_listen_socks(); | |
1497 | sock_in = newsock; | |
1498 | sock_out = newsock; | |
1b56ff3d | 1499 | close(startup_p[0]); |
1500 | close(startup_p[1]); | |
3c0ef626 | 1501 | startup_pipe = -1; |
1502 | pid = getpid(); | |
1b56ff3d | 1503 | if (rexec_flag) { |
1504 | send_rexec_state(config_s[0], | |
1505 | &cfg); | |
1506 | close(config_s[0]); | |
1507 | } | |
3c0ef626 | 1508 | break; |
1509 | } else { | |
1510 | /* | |
1511 | * Normal production daemon. Fork, and have | |
1512 | * the child process the connection. The | |
1513 | * parent continues listening. | |
1514 | */ | |
1515 | if ((pid = fork()) == 0) { | |
1516 | /* | |
1517 | * Child. Close the listening and max_startup | |
1518 | * sockets. Start using the accepted socket. | |
1519 | * Reinitialize logging (since our pid has | |
1520 | * changed). We break out of the loop to handle | |
1521 | * the connection. | |
1522 | */ | |
1523 | startup_pipe = startup_p[1]; | |
1e608e42 | 1524 | close_startup_pipes(); |
3c0ef626 | 1525 | close_listen_socks(); |
1526 | sock_in = newsock; | |
1527 | sock_out = newsock; | |
1528 | log_init(__progname, options.log_level, options.log_facility, log_stderr); | |
34fee935 | 1529 | if (rexec_flag) |
1530 | close(config_s[0]); | |
3c0ef626 | 1531 | break; |
1532 | } | |
1533 | } | |
1534 | ||
1535 | /* Parent. Stay in the loop. */ | |
1536 | if (pid < 0) | |
1537 | error("fork: %.100s", strerror(errno)); | |
1538 | else | |
ff2d7a98 | 1539 | debug("Forked child %ld.", (long)pid); |
3c0ef626 | 1540 | |
1541 | close(startup_p[1]); | |
1542 | ||
1b56ff3d | 1543 | if (rexec_flag) { |
1544 | send_rexec_state(config_s[0], &cfg); | |
1545 | close(config_s[0]); | |
1546 | close(config_s[1]); | |
1547 | } | |
1548 | ||
3c0ef626 | 1549 | /* Mark that the key has been used (it was "given" to the child). */ |
1550 | if ((options.protocol & SSH_PROTO_1) && | |
1551 | key_used == 0) { | |
1552 | /* Schedule server key regeneration alarm. */ | |
1553 | signal(SIGALRM, key_regeneration_alarm); | |
1554 | alarm(options.key_regeneration_time); | |
1555 | key_used = 1; | |
1556 | } | |
1557 | ||
1558 | arc4random_stir(); | |
1559 | ||
1560 | /* Close the new socket (the child is now taking care of it). */ | |
1561 | close(newsock); | |
1562 | } | |
1563 | /* child process check (or debug mode) */ | |
1564 | if (num_listen_socks < 0) | |
1565 | break; | |
1566 | } | |
1567 | } | |
1568 | ||
1569 | /* This is the child processing a new connection. */ | |
2a304a95 | 1570 | setproctitle("%s", "[accepted]"); |
3c0ef626 | 1571 | |
2980ea68 | 1572 | /* |
1573 | * Create a new session and process group since the 4.4BSD | |
1574 | * setlogin() affects the entire process group. We don't | |
1575 | * want the child to be able to affect the parent. | |
1576 | */ | |
70791e56 | 1577 | #if !defined(SSHD_ACQUIRES_CTTY) |
1c14df9e | 1578 | /* |
70791e56 | 1579 | * If setsid is called, on some platforms sshd will later acquire a |
1580 | * controlling terminal which will result in "could not set | |
1581 | * controlling tty" errors. | |
1c14df9e | 1582 | */ |
ff2d7a98 | 1583 | if (!debug_flag && !inetd_flag && setsid() < 0) |
2980ea68 | 1584 | error("setsid: %.100s", strerror(errno)); |
1585 | #endif | |
1586 | ||
1b56ff3d | 1587 | if (rexec_flag) { |
1588 | int fd; | |
1589 | ||
1590 | debug("rexec start in %d out %d newsock %d pipe %d sock %d", | |
1591 | sock_in, sock_out, newsock, startup_pipe, config_s[0]); | |
1592 | dup2(newsock, STDIN_FILENO); | |
1593 | dup2(STDIN_FILENO, STDOUT_FILENO); | |
1594 | if (startup_pipe == -1) | |
1595 | close(REEXEC_STARTUP_PIPE_FD); | |
1596 | else | |
1597 | dup2(startup_pipe, REEXEC_STARTUP_PIPE_FD); | |
1598 | ||
1599 | dup2(config_s[1], REEXEC_CONFIG_PASS_FD); | |
1600 | close(config_s[1]); | |
1601 | if (startup_pipe != -1) | |
1602 | close(startup_pipe); | |
1603 | ||
1604 | execv(rexec_argv[0], rexec_argv); | |
1605 | ||
1606 | /* Reexec has failed, fall back and continue */ | |
1607 | error("rexec of %s failed: %s", rexec_argv[0], strerror(errno)); | |
1608 | recv_rexec_state(REEXEC_CONFIG_PASS_FD, NULL); | |
1609 | log_init(__progname, options.log_level, | |
1610 | options.log_facility, log_stderr); | |
1611 | ||
1612 | /* Clean up fds */ | |
1613 | startup_pipe = REEXEC_STARTUP_PIPE_FD; | |
1614 | close(config_s[1]); | |
1615 | close(REEXEC_CONFIG_PASS_FD); | |
1616 | newsock = sock_out = sock_in = dup(STDIN_FILENO); | |
1617 | if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { | |
1618 | dup2(fd, STDIN_FILENO); | |
1619 | dup2(fd, STDOUT_FILENO); | |
1620 | if (fd > STDERR_FILENO) | |
1621 | close(fd); | |
1622 | } | |
1623 | debug("rexec cleanup in %d out %d newsock %d pipe %d sock %d", | |
1624 | sock_in, sock_out, newsock, startup_pipe, config_s[0]); | |
1625 | } | |
1626 | ||
3c0ef626 | 1627 | /* |
1628 | * Disable the key regeneration alarm. We will not regenerate the | |
1629 | * key since we are no longer in a position to give it to anyone. We | |
1630 | * will not restart on SIGHUP since it no longer makes sense. | |
1631 | */ | |
1632 | alarm(0); | |
1633 | signal(SIGALRM, SIG_DFL); | |
1634 | signal(SIGHUP, SIG_DFL); | |
1635 | signal(SIGTERM, SIG_DFL); | |
1636 | signal(SIGQUIT, SIG_DFL); | |
1637 | signal(SIGCHLD, SIG_DFL); | |
1638 | signal(SIGINT, SIG_DFL); | |
1639 | ||
3c0ef626 | 1640 | /* |
1641 | * Register our connection. This turns encryption off because we do | |
1642 | * not have a key. | |
1643 | */ | |
1644 | packet_set_connection(sock_in, sock_out); | |
34fee935 | 1645 | packet_set_server(); |
1646 | ||
1647 | /* Set SO_KEEPALIVE if requested. */ | |
1648 | if (options.tcp_keep_alive && packet_connection_is_on_socket() && | |
1649 | setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) < 0) | |
1650 | error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); | |
3c0ef626 | 1651 | |
34fee935 | 1652 | if ((remote_port = get_remote_port()) < 0) { |
1653 | debug("get_remote_port failed"); | |
1654 | cleanup_exit(255); | |
1655 | } | |
e00da40d | 1656 | |
1657 | /* | |
1658 | * We use get_canonical_hostname with usedns = 0 instead of | |
1659 | * get_remote_ipaddr here so IP options will be checked. | |
1660 | */ | |
1661 | remote_ip = get_canonical_hostname(0); | |
3c0ef626 | 1662 | |
34fee935 | 1663 | #ifdef SSH_AUDIT_EVENTS |
1664 | audit_connection_from(remote_ip, remote_port); | |
1665 | #endif | |
3c0ef626 | 1666 | #ifdef LIBWRAP |
1667 | /* Check whether logins are denied from this host. */ | |
1b56ff3d | 1668 | if (packet_connection_is_on_socket()) { |
3c0ef626 | 1669 | struct request_info req; |
1670 | ||
1671 | request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0); | |
1672 | fromhost(&req); | |
1673 | ||
1674 | if (!hosts_access(&req)) { | |
1675 | debug("Connection refused by tcp wrapper"); | |
1676 | refuse(&req); | |
1677 | /* NOTREACHED */ | |
1678 | fatal("libwrap refuse returns"); | |
1679 | } | |
1680 | } | |
1681 | #endif /* LIBWRAP */ | |
1682 | ||
1683 | /* Log the connection. */ | |
1684 | verbose("Connection from %.500s port %d", remote_ip, remote_port); | |
1685 | ||
34fee935 | 1686 | #ifdef USE_SECURITY_SESSION_API |
1687 | /* | |
1688 | * Create a new security session for use by the new user login if | |
1689 | * the current session is the root session or we are not launched | |
1690 | * by inetd (eg: debugging mode or server mode). We do not | |
1691 | * necessarily need to create a session if we are launched from | |
1692 | * inetd because Panther xinetd will create a session for us. | |
1693 | * | |
1694 | * The only case where this logic will fail is if there is an | |
1695 | * inetd running in a non-root session which is not creating | |
1696 | * new sessions for us. Then all the users will end up in the | |
1697 | * same session (bad). | |
1698 | * | |
1699 | * When the client exits, the session will be destroyed for us | |
1700 | * automatically. | |
1701 | * | |
1702 | * We must create the session before any credentials are stored | |
1703 | * (including AFS pags, which happens a few lines below). | |
1704 | */ | |
1705 | { | |
1706 | OSStatus err = 0; | |
1707 | SecuritySessionId sid = 0; | |
1708 | SessionAttributeBits sattrs = 0; | |
1709 | ||
1710 | err = SessionGetInfo(callerSecuritySession, &sid, &sattrs); | |
1711 | if (err) | |
1712 | error("SessionGetInfo() failed with error %.8X", | |
1713 | (unsigned) err); | |
1714 | else | |
1715 | debug("Current Session ID is %.8X / Session Attributes are %.8X", | |
1716 | (unsigned) sid, (unsigned) sattrs); | |
1717 | ||
1718 | if (inetd_flag && !(sattrs & sessionIsRoot)) | |
1719 | debug("Running in inetd mode in a non-root session... " | |
1720 | "assuming inetd created the session for us."); | |
1721 | else { | |
1722 | debug("Creating new security session..."); | |
1723 | err = SessionCreate(0, sessionHasTTY | sessionIsRemote); | |
1724 | if (err) | |
1725 | error("SessionCreate() failed with error %.8X", | |
1726 | (unsigned) err); | |
1727 | ||
1728 | err = SessionGetInfo(callerSecuritySession, &sid, | |
1729 | &sattrs); | |
1730 | if (err) | |
1731 | error("SessionGetInfo() failed with error %.8X", | |
1732 | (unsigned) err); | |
1733 | else | |
1734 | debug("New Session ID is %.8X / Session Attributes are %.8X", | |
1735 | (unsigned) sid, (unsigned) sattrs); | |
1736 | } | |
1737 | } | |
1738 | #endif | |
1739 | ||
3c0ef626 | 1740 | /* |
e00da40d | 1741 | * We don't want to listen forever unless the other side |
3c0ef626 | 1742 | * successfully authenticates itself. So we set up an alarm which is |
1743 | * cleared after successful authentication. A limit of zero | |
e00da40d | 1744 | * indicates no limit. Note that we don't set the alarm in debugging |
3c0ef626 | 1745 | * mode; it is just annoying to have the server exit just when you |
1746 | * are about to discover the bug. | |
1747 | */ | |
1748 | signal(SIGALRM, grace_alarm_handler); | |
1749 | if (!debug_flag) | |
1750 | alarm(options.login_grace_time); | |
1751 | ||
1752 | sshd_exchange_identification(sock_in, sock_out); | |
70791e56 | 1753 | #if defined(AFS_KRB5) |
3c0ef626 | 1754 | /* If machine has AFS, set process authentication group. */ |
1755 | if (k_hasafs()) { | |
1756 | k_setpag(); | |
1757 | k_unlog(); | |
1758 | } | |
f2fd21a2 | 1759 | #endif /* AFS || AFS_KRB5 */ |
3c0ef626 | 1760 | |
1761 | packet_set_nonblocking(); | |
1762 | ||
416fd2a8 | 1763 | /* allocate authentication context */ |
1764 | authctxt = xmalloc(sizeof(*authctxt)); | |
1765 | memset(authctxt, 0, sizeof(*authctxt)); | |
1766 | ||
34fee935 | 1767 | authctxt->loginmsg = &loginmsg; |
1768 | ||
416fd2a8 | 1769 | /* XXX global for cleanup, access from other modules */ |
1770 | the_authctxt = authctxt; | |
1771 | ||
34fee935 | 1772 | /* prepare buffer to collect messages to display to user after login */ |
1773 | buffer_init(&loginmsg); | |
1774 | ||
2980ea68 | 1775 | if (use_privsep) |
416fd2a8 | 1776 | if (privsep_preauth(authctxt) == 1) |
2980ea68 | 1777 | goto authenticated; |
1778 | ||
3c0ef626 | 1779 | /* perform the key exchange */ |
1780 | /* authenticate user and start session */ | |
1781 | if (compat20) { | |
1782 | do_ssh2_kex(); | |
416fd2a8 | 1783 | do_authentication2(authctxt); |
3c0ef626 | 1784 | } else { |
1785 | do_ssh1_kex(); | |
416fd2a8 | 1786 | do_authentication(authctxt); |
2980ea68 | 1787 | } |
1788 | /* | |
1789 | * If we use privilege separation, the unprivileged child transfers | |
1790 | * the current keystate and exits | |
1791 | */ | |
1792 | if (use_privsep) { | |
1793 | mm_send_keystate(pmonitor); | |
1794 | exit(0); | |
3c0ef626 | 1795 | } |
2980ea68 | 1796 | |
1797 | authenticated: | |
e00da40d | 1798 | /* |
1799 | * Cancel the alarm we set to limit the time taken for | |
1800 | * authentication. | |
1801 | */ | |
1802 | alarm(0); | |
1803 | signal(SIGALRM, SIG_DFL); | |
1804 | if (startup_pipe != -1) { | |
1805 | close(startup_pipe); | |
1806 | startup_pipe = -1; | |
1807 | } | |
1808 | ||
34fee935 | 1809 | #ifdef SSH_AUDIT_EVENTS |
1810 | audit_event(SSH_AUTH_SUCCESS); | |
1811 | #endif | |
1812 | ||
2980ea68 | 1813 | /* |
1814 | * In privilege separation, we fork another child and prepare | |
1815 | * file descriptor passing. | |
1816 | */ | |
1817 | if (use_privsep) { | |
1818 | privsep_postauth(authctxt); | |
1819 | /* the monitor process [priv] will not return */ | |
1820 | if (!compat20) | |
1821 | destroy_sensitive_data(); | |
1822 | } | |
1823 | ||
416fd2a8 | 1824 | /* Start session. */ |
2980ea68 | 1825 | do_authenticated(authctxt); |
1826 | ||
3c0ef626 | 1827 | /* The connection has been terminated. */ |
1828 | verbose("Closing connection to %.100s", remote_ip); | |
1829 | ||
1830 | #ifdef USE_PAM | |
70791e56 | 1831 | if (options.use_pam) |
1832 | finish_pam(); | |
3c0ef626 | 1833 | #endif /* USE_PAM */ |
1834 | ||
34fee935 | 1835 | #ifdef SSH_AUDIT_EVENTS |
1836 | PRIVSEP(audit_event(SSH_CONNECTION_CLOSE)); | |
1837 | #endif | |
1838 | ||
3c0ef626 | 1839 | packet_close(); |
2980ea68 | 1840 | |
1841 | if (use_privsep) | |
1842 | mm_terminate(); | |
1843 | ||
3c0ef626 | 1844 | exit(0); |
1845 | } | |
1846 | ||
2980ea68 | 1847 | /* |
1848 | * Decrypt session_key_int using our private server key and private host key | |
1849 | * (key with larger modulus first). | |
1850 | */ | |
1851 | int | |
1852 | ssh1_session_key(BIGNUM *session_key_int) | |
1853 | { | |
1854 | int rsafail = 0; | |
1855 | ||
1856 | if (BN_cmp(sensitive_data.server_key->rsa->n, sensitive_data.ssh1_host_key->rsa->n) > 0) { | |
1857 | /* Server key has bigger modulus. */ | |
1858 | if (BN_num_bits(sensitive_data.server_key->rsa->n) < | |
1859 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + SSH_KEY_BITS_RESERVED) { | |
1860 | fatal("do_connection: %s: server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d", | |
1861 | get_remote_ipaddr(), | |
1862 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
1863 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), | |
1864 | SSH_KEY_BITS_RESERVED); | |
1865 | } | |
1866 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1867 | sensitive_data.server_key->rsa) <= 0) | |
1868 | rsafail++; | |
1869 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1870 | sensitive_data.ssh1_host_key->rsa) <= 0) | |
1871 | rsafail++; | |
1872 | } else { | |
1873 | /* Host key has bigger modulus (or they are equal). */ | |
1874 | if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) < | |
1875 | BN_num_bits(sensitive_data.server_key->rsa->n) + SSH_KEY_BITS_RESERVED) { | |
1876 | fatal("do_connection: %s: host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d", | |
1877 | get_remote_ipaddr(), | |
1878 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), | |
1879 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
1880 | SSH_KEY_BITS_RESERVED); | |
1881 | } | |
1882 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1883 | sensitive_data.ssh1_host_key->rsa) < 0) | |
1884 | rsafail++; | |
1885 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1886 | sensitive_data.server_key->rsa) < 0) | |
1887 | rsafail++; | |
1888 | } | |
1889 | return (rsafail); | |
1890 | } | |
3c0ef626 | 1891 | /* |
1892 | * SSH1 key exchange | |
1893 | */ | |
1894 | static void | |
1895 | do_ssh1_kex(void) | |
1896 | { | |
1897 | int i, len; | |
3c0ef626 | 1898 | int rsafail = 0; |
1899 | BIGNUM *session_key_int; | |
1900 | u_char session_key[SSH_SESSION_KEY_LENGTH]; | |
1901 | u_char cookie[8]; | |
1902 | u_int cipher_type, auth_mask, protocol_flags; | |
e54b3d7c | 1903 | u_int32_t rnd = 0; |
3c0ef626 | 1904 | |
1905 | /* | |
1906 | * Generate check bytes that the client must send back in the user | |
1907 | * packet in order for it to be accepted; this is used to defy ip | |
1908 | * spoofing attacks. Note that this only works against somebody | |
1909 | * doing IP spoofing from a remote machine; any machine on the local | |
1910 | * network can still see outgoing packets and catch the random | |
1911 | * cookie. This only affects rhosts authentication, and this is one | |
1912 | * of the reasons why it is inherently insecure. | |
1913 | */ | |
1914 | for (i = 0; i < 8; i++) { | |
1915 | if (i % 4 == 0) | |
e54b3d7c | 1916 | rnd = arc4random(); |
1917 | cookie[i] = rnd & 0xff; | |
1918 | rnd >>= 8; | |
3c0ef626 | 1919 | } |
1920 | ||
1921 | /* | |
1922 | * Send our public key. We include in the packet 64 bits of random | |
1923 | * data that must be matched in the reply in order to prevent IP | |
1924 | * spoofing. | |
1925 | */ | |
1926 | packet_start(SSH_SMSG_PUBLIC_KEY); | |
1927 | for (i = 0; i < 8; i++) | |
1928 | packet_put_char(cookie[i]); | |
1929 | ||
1930 | /* Store our public server RSA key. */ | |
1931 | packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n)); | |
1932 | packet_put_bignum(sensitive_data.server_key->rsa->e); | |
1933 | packet_put_bignum(sensitive_data.server_key->rsa->n); | |
1934 | ||
1935 | /* Store our public host RSA key. */ | |
1936 | packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); | |
1937 | packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e); | |
1938 | packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n); | |
1939 | ||
1940 | /* Put protocol flags. */ | |
1941 | packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN); | |
1942 | ||
1943 | /* Declare which ciphers we support. */ | |
1944 | packet_put_int(cipher_mask_ssh1(0)); | |
1945 | ||
1946 | /* Declare supported authentication types. */ | |
1947 | auth_mask = 0; | |
3c0ef626 | 1948 | if (options.rhosts_rsa_authentication) |
1949 | auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA; | |
1950 | if (options.rsa_authentication) | |
1951 | auth_mask |= 1 << SSH_AUTH_RSA; | |
ff2d7a98 | 1952 | if (options.challenge_response_authentication == 1) |
1953 | auth_mask |= 1 << SSH_AUTH_TIS; | |
3c0ef626 | 1954 | if (options.password_authentication) |
1955 | auth_mask |= 1 << SSH_AUTH_PASSWORD; | |
1956 | packet_put_int(auth_mask); | |
1957 | ||
1958 | /* Send the packet and wait for it to be sent. */ | |
1959 | packet_send(); | |
1960 | packet_write_wait(); | |
1961 | ||
1962 | debug("Sent %d bit server key and %d bit host key.", | |
1963 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
1964 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); | |
1965 | ||
1966 | /* Read clients reply (cipher type and session key). */ | |
1e608e42 | 1967 | packet_read_expect(SSH_CMSG_SESSION_KEY); |
3c0ef626 | 1968 | |
1969 | /* Get cipher type and check whether we accept this. */ | |
1970 | cipher_type = packet_get_char(); | |
1971 | ||
1972 | if (!(cipher_mask_ssh1(0) & (1 << cipher_type))) | |
1973 | packet_disconnect("Warning: client selects unsupported cipher."); | |
1974 | ||
1975 | /* Get check bytes from the packet. These must match those we | |
1976 | sent earlier with the public key packet. */ | |
1977 | for (i = 0; i < 8; i++) | |
1978 | if (cookie[i] != packet_get_char()) | |
1979 | packet_disconnect("IP Spoofing check bytes do not match."); | |
1980 | ||
1981 | debug("Encryption type: %.200s", cipher_name(cipher_type)); | |
1982 | ||
1983 | /* Get the encrypted integer. */ | |
1e608e42 | 1984 | if ((session_key_int = BN_new()) == NULL) |
1985 | fatal("do_ssh1_kex: BN_new failed"); | |
1986 | packet_get_bignum(session_key_int); | |
3c0ef626 | 1987 | |
1988 | protocol_flags = packet_get_int(); | |
1989 | packet_set_protocol_flags(protocol_flags); | |
1e608e42 | 1990 | packet_check_eom(); |
3c0ef626 | 1991 | |
2980ea68 | 1992 | /* Decrypt session_key_int using host/server keys */ |
1993 | rsafail = PRIVSEP(ssh1_session_key(session_key_int)); | |
1994 | ||
3c0ef626 | 1995 | /* |
1996 | * Extract session key from the decrypted integer. The key is in the | |
1997 | * least significant 256 bits of the integer; the first byte of the | |
1998 | * key is in the highest bits. | |
1999 | */ | |
2000 | if (!rsafail) { | |
2001 | BN_mask_bits(session_key_int, sizeof(session_key) * 8); | |
2002 | len = BN_num_bytes(session_key_int); | |
34fee935 | 2003 | if (len < 0 || (u_int)len > sizeof(session_key)) { |
3c0ef626 | 2004 | error("do_connection: bad session key len from %s: " |
2005 | "session_key_int %d > sizeof(session_key) %lu", | |
2006 | get_remote_ipaddr(), len, (u_long)sizeof(session_key)); | |
2007 | rsafail++; | |
2008 | } else { | |
2009 | memset(session_key, 0, sizeof(session_key)); | |
2010 | BN_bn2bin(session_key_int, | |
2011 | session_key + sizeof(session_key) - len); | |
2012 | ||
1b56ff3d | 2013 | derive_ssh1_session_id( |
3c0ef626 | 2014 | sensitive_data.ssh1_host_key->rsa->n, |
1b56ff3d | 2015 | sensitive_data.server_key->rsa->n, |
2016 | cookie, session_id); | |
3c0ef626 | 2017 | /* |
2018 | * Xor the first 16 bytes of the session key with the | |
2019 | * session id. | |
2020 | */ | |
2021 | for (i = 0; i < 16; i++) | |
2022 | session_key[i] ^= session_id[i]; | |
2023 | } | |
2024 | } | |
2025 | if (rsafail) { | |
2026 | int bytes = BN_num_bytes(session_key_int); | |
1e608e42 | 2027 | u_char *buf = xmalloc(bytes); |
3c0ef626 | 2028 | MD5_CTX md; |
2029 | ||
70791e56 | 2030 | logit("do_connection: generating a fake encryption key"); |
3c0ef626 | 2031 | BN_bn2bin(session_key_int, buf); |
2032 | MD5_Init(&md); | |
2033 | MD5_Update(&md, buf, bytes); | |
2034 | MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); | |
2035 | MD5_Final(session_key, &md); | |
2036 | MD5_Init(&md); | |
2037 | MD5_Update(&md, session_key, 16); | |
2038 | MD5_Update(&md, buf, bytes); | |
2039 | MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); | |
2040 | MD5_Final(session_key + 16, &md); | |
2041 | memset(buf, 0, bytes); | |
2042 | xfree(buf); | |
2043 | for (i = 0; i < 16; i++) | |
2044 | session_id[i] = session_key[i] ^ session_key[i + 16]; | |
2045 | } | |
2980ea68 | 2046 | /* Destroy the private and public keys. No longer. */ |
3c0ef626 | 2047 | destroy_sensitive_data(); |
2048 | ||
2980ea68 | 2049 | if (use_privsep) |
2050 | mm_ssh1_session_id(session_id); | |
2051 | ||
3c0ef626 | 2052 | /* Destroy the decrypted integer. It is no longer needed. */ |
2053 | BN_clear_free(session_key_int); | |
2054 | ||
2055 | /* Set the session key. From this on all communications will be encrypted. */ | |
2056 | packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type); | |
2057 | ||
2058 | /* Destroy our copy of the session key. It is no longer needed. */ | |
2059 | memset(session_key, 0, sizeof(session_key)); | |
2060 | ||
2061 | debug("Received session key; encryption turned on."); | |
2062 | ||
ff2d7a98 | 2063 | /* Send an acknowledgment packet. Note that this packet is sent encrypted. */ |
3c0ef626 | 2064 | packet_start(SSH_SMSG_SUCCESS); |
2065 | packet_send(); | |
2066 | packet_write_wait(); | |
2067 | } | |
2068 | ||
2069 | /* | |
2070 | * SSH2 key exchange: diffie-hellman-group1-sha1 | |
2071 | */ | |
2072 | static void | |
2073 | do_ssh2_kex(void) | |
2074 | { | |
2075 | Kex *kex; | |
2076 | ||
2077 | if (options.ciphers != NULL) { | |
2078 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = | |
2079 | myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; | |
e00da40d | 2080 | } else if (options.none_enabled == 1) { |
2081 | debug ("WARNING: None cipher enabled"); | |
2082 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = | |
2083 | myproposal[PROPOSAL_ENC_ALGS_STOC] = KEX_ENCRYPT_INCLUDE_NONE; | |
3c0ef626 | 2084 | } |
2085 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = | |
2086 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]); | |
2087 | myproposal[PROPOSAL_ENC_ALGS_STOC] = | |
2088 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); | |
2089 | ||
2090 | if (options.macs != NULL) { | |
2091 | myproposal[PROPOSAL_MAC_ALGS_CTOS] = | |
2092 | myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; | |
2093 | } | |
34fee935 | 2094 | if (options.compression == COMP_NONE) { |
ff2d7a98 | 2095 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = |
2096 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "none"; | |
34fee935 | 2097 | } else if (options.compression == COMP_DELAYED) { |
2098 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = | |
2099 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com"; | |
ff2d7a98 | 2100 | } |
34fee935 | 2101 | |
3c0ef626 | 2102 | myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = list_hostkey_types(); |
2103 | ||
34fee935 | 2104 | /* start key exchange */ |
2105 | ||
5598e598 | 2106 | #ifdef GSSAPI |
34fee935 | 2107 | { |
5598e598 | 2108 | char *orig; |
2109 | char *gss = NULL; | |
2110 | char *newstr = NULL; | |
34fee935 | 2111 | orig = myproposal[PROPOSAL_KEX_ALGS]; |
2112 | ||
2113 | /* | |
2114 | * If we don't have a host key, then there's no point advertising | |
2115 | * the other key exchange algorithms | |
2116 | */ | |
2117 | ||
2118 | if (strlen(myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS]) == 0) | |
2119 | orig = NULL; | |
2120 | ||
2121 | if (options.gss_keyex) | |
2122 | gss = ssh_gssapi_server_mechanisms(); | |
2123 | else | |
2124 | gss = NULL; | |
2125 | ||
5598e598 | 2126 | if (gss && orig) { |
34fee935 | 2127 | int len = strlen(orig) + strlen(gss) + 2; |
2128 | newstr = xmalloc(len); | |
2129 | snprintf(newstr, len, "%s,%s", gss, orig); | |
5598e598 | 2130 | } else if (gss) { |
34fee935 | 2131 | newstr = gss; |
5598e598 | 2132 | } else if (orig) { |
34fee935 | 2133 | newstr = orig; |
5598e598 | 2134 | } |
34fee935 | 2135 | /* |
2136 | * If we've got GSSAPI mechanisms, then we've got the 'null' host | |
2137 | * key alg, but we can't tell people about it unless its the only | |
2138 | * host key algorithm we support | |
2139 | */ | |
2140 | if (gss && (strlen(myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS])) == 0) | |
2141 | myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = "null"; | |
2142 | ||
5598e598 | 2143 | if (newstr) |
34fee935 | 2144 | myproposal[PROPOSAL_KEX_ALGS] = newstr; |
5598e598 | 2145 | else |
2146 | fatal("No supported key exchange algorithms"); | |
34fee935 | 2147 | } |
5598e598 | 2148 | #endif |
2149 | ||
34fee935 | 2150 | /* start key exchange */ |
2151 | kex = kex_setup(myproposal); | |
2152 | kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server; | |
1b56ff3d | 2153 | kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server; |
1c14df9e | 2154 | kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; |
2155 | #ifdef GSSAPI | |
2156 | kex->kex[KEX_GSS_GRP1_SHA1] = kexgss_server; | |
34fee935 | 2157 | kex->kex[KEX_GSS_GEX_SHA1] = kexgss_server; |
1c14df9e | 2158 | #endif |
34fee935 | 2159 | kex->server = 1; |
2160 | kex->client_version_string=client_version_string; | |
2161 | kex->server_version_string=server_version_string; | |
3c0ef626 | 2162 | kex->load_host_key=&get_hostkey_by_type; |
2980ea68 | 2163 | kex->host_key_index=&get_hostkey_index; |
3c0ef626 | 2164 | |
2165 | xxx_kex = kex; | |
2166 | ||
2167 | dispatch_run(DISPATCH_BLOCK, &kex->done, kex); | |
2168 | ||
2169 | session_id2 = kex->session_id; | |
2170 | session_id2_len = kex->session_id_len; | |
2171 | ||
2172 | #ifdef DEBUG_KEXDH | |
2173 | /* send 1st encrypted/maced/compressed message */ | |
2174 | packet_start(SSH2_MSG_IGNORE); | |
2175 | packet_put_cstring("markus"); | |
2176 | packet_send(); | |
2177 | packet_write_wait(); | |
2178 | #endif | |
2179 | debug("KEX done"); | |
2180 | } | |
416fd2a8 | 2181 | |
2182 | /* server specific fatal cleanup */ | |
2183 | void | |
2184 | cleanup_exit(int i) | |
2185 | { | |
2186 | if (the_authctxt) | |
2187 | do_cleanup(the_authctxt); | |
34fee935 | 2188 | #ifdef SSH_AUDIT_EVENTS |
2189 | /* done after do_cleanup so it can cancel the PAM auth 'thread' */ | |
2190 | if (!use_privsep || mm_is_monitor()) | |
2191 | audit_event(SSH_CONNECTION_ABANDON); | |
2192 | #endif | |
416fd2a8 | 2193 | _exit(i); |
2194 | } |