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b5afdff5 | 1 | /* $OpenBSD: sshd.c,v 1.367 2009/05/28 16:50:16 andreas 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: | |
510132b6 | 19 | * Privilege Separation: |
3c0ef626 | 20 | * |
510132b6 | 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" | |
30460aeb | 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" | |
5156b1a1 | 57 | #include "openbsd-compat/sys-queue.h" |
30460aeb | 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> |
510132b6 | 78 | #include <openssl/rand.h> |
e74dc197 | 79 | #include "openbsd-compat/openssl-compat.h" |
80 | ||
510132b6 | 81 | #ifdef HAVE_SECUREWARE |
82 | #include <sys/security.h> | |
83 | #include <prot.h> | |
84 | #endif | |
3c0ef626 | 85 | |
30460aeb | 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" |
30460aeb | 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" |
30460aeb | 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" | |
30460aeb | 107 | #include "hostfile.h" |
3c0ef626 | 108 | #include "auth.h" |
109 | #include "misc.h" | |
7e82606e | 110 | #include "msg.h" |
3c0ef626 | 111 | #include "dispatch.h" |
112 | #include "channels.h" | |
510132b6 | 113 | #include "session.h" |
114 | #include "monitor_mm.h" | |
115 | #include "monitor.h" | |
30460aeb | 116 | #ifdef GSSAPI |
117 | #include "ssh-gss.h" | |
118 | #endif | |
510132b6 | 119 | #include "monitor_wrap.h" |
b5afdff5 | 120 | #include "roaming.h" |
30460aeb | 121 | #include "version.h" |
3c0ef626 | 122 | |
fe4ad273 | 123 | #ifdef USE_SECURITY_SESSION_API |
124 | #include <Security/AuthSession.h> | |
5598e598 | 125 | #endif |
126 | ||
3c0ef626 | 127 | #ifdef LIBWRAP |
128 | #include <tcpd.h> | |
129 | #include <syslog.h> | |
e74dc197 | 130 | int allow_severity; |
131 | int deny_severity; | |
3c0ef626 | 132 | #endif /* LIBWRAP */ |
133 | ||
134 | #ifndef O_NOCTTY | |
135 | #define O_NOCTTY 0 | |
136 | #endif | |
137 | ||
7e82606e | 138 | /* Re-exec fds */ |
139 | #define REEXEC_DEVCRYPTO_RESERVED_FD (STDERR_FILENO + 1) | |
140 | #define REEXEC_STARTUP_PIPE_FD (STDERR_FILENO + 2) | |
141 | #define REEXEC_CONFIG_PASS_FD (STDERR_FILENO + 3) | |
142 | #define REEXEC_MIN_FREE_FD (STDERR_FILENO + 4) | |
143 | ||
6df46d40 | 144 | int myflag = 0; |
145 | ||
146 | ||
3c0ef626 | 147 | extern char *__progname; |
3c0ef626 | 148 | |
149 | /* Server configuration options. */ | |
150 | ServerOptions options; | |
151 | ||
152 | /* Name of the server configuration file. */ | |
153 | char *config_file_name = _PATH_SERVER_CONFIG_FILE; | |
154 | ||
3c0ef626 | 155 | /* |
156 | * Debug mode flag. This can be set on the command line. If debug | |
157 | * mode is enabled, extra debugging output will be sent to the system | |
158 | * log, the daemon will not go to background, and will exit after processing | |
159 | * the first connection. | |
160 | */ | |
161 | int debug_flag = 0; | |
162 | ||
163 | /* Flag indicating that the daemon should only test the configuration and keys. */ | |
164 | int test_flag = 0; | |
165 | ||
166 | /* Flag indicating that the daemon is being started from inetd. */ | |
167 | int inetd_flag = 0; | |
168 | ||
169 | /* Flag indicating that sshd should not detach and become a daemon. */ | |
170 | int no_daemon_flag = 0; | |
171 | ||
172 | /* debug goes to stderr unless inetd_flag is set */ | |
173 | int log_stderr = 0; | |
174 | ||
175 | /* Saved arguments to main(). */ | |
176 | char **saved_argv; | |
177 | int saved_argc; | |
178 | ||
7e82606e | 179 | /* re-exec */ |
180 | int rexeced_flag = 0; | |
181 | int rexec_flag = 1; | |
182 | int rexec_argc = 0; | |
183 | char **rexec_argv; | |
184 | ||
3c0ef626 | 185 | /* |
186 | * The sockets that the server is listening; this is used in the SIGHUP | |
187 | * signal handler. | |
188 | */ | |
189 | #define MAX_LISTEN_SOCKS 16 | |
190 | int listen_socks[MAX_LISTEN_SOCKS]; | |
191 | int num_listen_socks = 0; | |
192 | ||
193 | /* | |
194 | * the client's version string, passed by sshd2 in compat mode. if != NULL, | |
195 | * sshd will skip the version-number exchange | |
196 | */ | |
197 | char *client_version_string = NULL; | |
198 | char *server_version_string = NULL; | |
199 | ||
200 | /* for rekeying XXX fixme */ | |
201 | Kex *xxx_kex; | |
202 | ||
203 | /* | |
204 | * Any really sensitive data in the application is contained in this | |
205 | * structure. The idea is that this structure could be locked into memory so | |
206 | * that the pages do not get written into swap. However, there are some | |
207 | * problems. The private key contains BIGNUMs, and we do not (in principle) | |
208 | * have access to the internals of them, and locking just the structure is | |
209 | * not very useful. Currently, memory locking is not implemented. | |
210 | */ | |
211 | struct { | |
212 | Key *server_key; /* ephemeral server key */ | |
213 | Key *ssh1_host_key; /* ssh1 host key */ | |
214 | Key **host_keys; /* all private host keys */ | |
215 | int have_ssh1_key; | |
216 | int have_ssh2_key; | |
217 | u_char ssh1_cookie[SSH_SESSION_KEY_LENGTH]; | |
218 | } sensitive_data; | |
219 | ||
220 | /* | |
221 | * Flag indicating whether the RSA server key needs to be regenerated. | |
222 | * Is set in the SIGALRM handler and cleared when the key is regenerated. | |
223 | */ | |
1e608e42 | 224 | static volatile sig_atomic_t key_do_regen = 0; |
3c0ef626 | 225 | |
226 | /* This is set to true when a signal is received. */ | |
1e608e42 | 227 | static volatile sig_atomic_t received_sighup = 0; |
228 | static volatile sig_atomic_t received_sigterm = 0; | |
3c0ef626 | 229 | |
230 | /* session identifier, used by RSA-auth */ | |
231 | u_char session_id[16]; | |
232 | ||
233 | /* same for ssh2 */ | |
234 | u_char *session_id2 = NULL; | |
7cac2b65 | 235 | u_int session_id2_len = 0; |
3c0ef626 | 236 | |
237 | /* record remote hostname or ip */ | |
238 | u_int utmp_len = MAXHOSTNAMELEN; | |
239 | ||
1e608e42 | 240 | /* options.max_startup sized array of fd ints */ |
241 | int *startup_pipes = NULL; | |
242 | int startup_pipe; /* in child */ | |
243 | ||
510132b6 | 244 | /* variables used for privilege separation */ |
30460aeb | 245 | int use_privsep = -1; |
540d72c3 | 246 | struct monitor *pmonitor = NULL; |
510132b6 | 247 | |
540d72c3 | 248 | /* global authentication context */ |
249 | Authctxt *the_authctxt = NULL; | |
250 | ||
30460aeb | 251 | /* sshd_config buffer */ |
252 | Buffer cfg; | |
253 | ||
7e82606e | 254 | /* message to be displayed after login */ |
255 | Buffer loginmsg; | |
256 | ||
30460aeb | 257 | /* Unprivileged user */ |
258 | struct passwd *privsep_pw = NULL; | |
259 | ||
3c0ef626 | 260 | /* Prototypes for various functions defined later in this file. */ |
261 | void destroy_sensitive_data(void); | |
510132b6 | 262 | void demote_sensitive_data(void); |
3c0ef626 | 263 | |
264 | static void do_ssh1_kex(void); | |
265 | static void do_ssh2_kex(void); | |
266 | ||
267 | /* | |
268 | * Close all listening sockets | |
269 | */ | |
270 | static void | |
271 | close_listen_socks(void) | |
272 | { | |
273 | int i; | |
276b07a3 | 274 | |
3c0ef626 | 275 | for (i = 0; i < num_listen_socks; i++) |
276 | close(listen_socks[i]); | |
277 | num_listen_socks = -1; | |
278 | } | |
279 | ||
1e608e42 | 280 | static void |
281 | close_startup_pipes(void) | |
282 | { | |
283 | int i; | |
276b07a3 | 284 | |
1e608e42 | 285 | if (startup_pipes) |
286 | for (i = 0; i < options.max_startups; i++) | |
287 | if (startup_pipes[i] != -1) | |
288 | close(startup_pipes[i]); | |
289 | } | |
290 | ||
3c0ef626 | 291 | /* |
292 | * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP; | |
293 | * the effect is to reread the configuration file (and to regenerate | |
294 | * the server key). | |
295 | */ | |
30460aeb | 296 | |
297 | /*ARGSUSED*/ | |
3c0ef626 | 298 | static void |
299 | sighup_handler(int sig) | |
300 | { | |
1e608e42 | 301 | int save_errno = errno; |
302 | ||
3c0ef626 | 303 | received_sighup = 1; |
304 | signal(SIGHUP, sighup_handler); | |
1e608e42 | 305 | errno = save_errno; |
3c0ef626 | 306 | } |
307 | ||
308 | /* | |
309 | * Called from the main program after receiving SIGHUP. | |
310 | * Restarts the server. | |
311 | */ | |
312 | static void | |
313 | sighup_restart(void) | |
314 | { | |
7cac2b65 | 315 | logit("Received SIGHUP; restarting."); |
3c0ef626 | 316 | close_listen_socks(); |
1e608e42 | 317 | close_startup_pipes(); |
0b90ac93 | 318 | alarm(0); /* alarm timer persists across exec */ |
3c0ef626 | 319 | execv(saved_argv[0], saved_argv); |
7cac2b65 | 320 | logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0], |
276b07a3 | 321 | strerror(errno)); |
3c0ef626 | 322 | exit(1); |
323 | } | |
324 | ||
325 | /* | |
326 | * Generic signal handler for terminating signals in the master daemon. | |
327 | */ | |
30460aeb | 328 | /*ARGSUSED*/ |
3c0ef626 | 329 | static void |
330 | sigterm_handler(int sig) | |
331 | { | |
332 | received_sigterm = sig; | |
333 | } | |
334 | ||
335 | /* | |
336 | * SIGCHLD handler. This is called whenever a child dies. This will then | |
337 | * reap any zombies left by exited children. | |
338 | */ | |
30460aeb | 339 | /*ARGSUSED*/ |
3c0ef626 | 340 | static void |
341 | main_sigchld_handler(int sig) | |
342 | { | |
343 | int save_errno = errno; | |
276b07a3 | 344 | pid_t pid; |
3c0ef626 | 345 | int status; |
346 | ||
510132b6 | 347 | while ((pid = waitpid(-1, &status, WNOHANG)) > 0 || |
348 | (pid < 0 && errno == EINTR)) | |
3c0ef626 | 349 | ; |
350 | ||
351 | signal(SIGCHLD, main_sigchld_handler); | |
352 | errno = save_errno; | |
353 | } | |
354 | ||
355 | /* | |
356 | * Signal handler for the alarm after the login grace period has expired. | |
357 | */ | |
30460aeb | 358 | /*ARGSUSED*/ |
3c0ef626 | 359 | static void |
360 | grace_alarm_handler(int sig) | |
361 | { | |
540d72c3 | 362 | if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0) |
363 | kill(pmonitor->m_pid, SIGALRM); | |
364 | ||
3c0ef626 | 365 | /* Log error and exit. */ |
30460aeb | 366 | sigdie("Timeout before authentication for %s", get_remote_ipaddr()); |
3c0ef626 | 367 | } |
368 | ||
369 | /* | |
370 | * Signal handler for the key regeneration alarm. Note that this | |
371 | * alarm only occurs in the daemon waiting for connections, and it does not | |
372 | * do anything with the private key or random state before forking. | |
373 | * Thus there should be no concurrency control/asynchronous execution | |
374 | * problems. | |
375 | */ | |
376 | static void | |
377 | generate_ephemeral_server_key(void) | |
378 | { | |
3c0ef626 | 379 | verbose("Generating %s%d bit RSA key.", |
380 | sensitive_data.server_key ? "new " : "", options.server_key_bits); | |
381 | if (sensitive_data.server_key != NULL) | |
382 | key_free(sensitive_data.server_key); | |
383 | sensitive_data.server_key = key_generate(KEY_RSA1, | |
384 | options.server_key_bits); | |
385 | verbose("RSA key generation complete."); | |
386 | ||
5156b1a1 | 387 | arc4random_buf(sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); |
3c0ef626 | 388 | arc4random_stir(); |
389 | } | |
390 | ||
30460aeb | 391 | /*ARGSUSED*/ |
3c0ef626 | 392 | static void |
393 | key_regeneration_alarm(int sig) | |
394 | { | |
395 | int save_errno = errno; | |
276b07a3 | 396 | |
3c0ef626 | 397 | signal(SIGALRM, SIG_DFL); |
398 | errno = save_errno; | |
399 | key_do_regen = 1; | |
400 | } | |
401 | ||
402 | static void | |
403 | sshd_exchange_identification(int sock_in, int sock_out) | |
404 | { | |
2ce0bfe4 | 405 | u_int i; |
406 | int mismatch; | |
3c0ef626 | 407 | int remote_major, remote_minor; |
408 | int major, minor; | |
5156b1a1 | 409 | char *s, *newline = "\n"; |
3c0ef626 | 410 | char buf[256]; /* Must not be larger than remote_version. */ |
411 | char remote_version[256]; /* Must be at least as big as buf. */ | |
412 | ||
413 | if ((options.protocol & SSH_PROTO_1) && | |
414 | (options.protocol & SSH_PROTO_2)) { | |
415 | major = PROTOCOL_MAJOR_1; | |
416 | minor = 99; | |
417 | } else if (options.protocol & SSH_PROTO_2) { | |
418 | major = PROTOCOL_MAJOR_2; | |
419 | minor = PROTOCOL_MINOR_2; | |
5156b1a1 | 420 | newline = "\r\n"; |
3c0ef626 | 421 | } else { |
422 | major = PROTOCOL_MAJOR_1; | |
423 | minor = PROTOCOL_MINOR_1; | |
424 | } | |
5156b1a1 | 425 | snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s%s", major, minor, |
426 | SSH_RELEASE, newline); | |
3c0ef626 | 427 | server_version_string = xstrdup(buf); |
428 | ||
7cac2b65 | 429 | /* Send our protocol version identification. */ |
b5afdff5 | 430 | if (roaming_atomicio(vwrite, sock_out, server_version_string, |
7cac2b65 | 431 | strlen(server_version_string)) |
432 | != strlen(server_version_string)) { | |
433 | logit("Could not write ident string to %s", get_remote_ipaddr()); | |
540d72c3 | 434 | cleanup_exit(255); |
7cac2b65 | 435 | } |
436 | ||
437 | /* Read other sides version identification. */ | |
438 | memset(buf, 0, sizeof(buf)); | |
439 | for (i = 0; i < sizeof(buf) - 1; i++) { | |
b5afdff5 | 440 | if (roaming_atomicio(read, sock_in, &buf[i], 1) != 1) { |
7cac2b65 | 441 | logit("Did not receive identification string from %s", |
442 | get_remote_ipaddr()); | |
540d72c3 | 443 | cleanup_exit(255); |
3c0ef626 | 444 | } |
7cac2b65 | 445 | if (buf[i] == '\r') { |
446 | buf[i] = 0; | |
447 | /* Kludge for F-Secure Macintosh < 1.0.2 */ | |
448 | if (i == 12 && | |
449 | strncmp(buf, "SSH-1.5-W1.0", 12) == 0) | |
3c0ef626 | 450 | break; |
7cac2b65 | 451 | continue; |
452 | } | |
453 | if (buf[i] == '\n') { | |
454 | buf[i] = 0; | |
455 | break; | |
3c0ef626 | 456 | } |
3c0ef626 | 457 | } |
7cac2b65 | 458 | buf[sizeof(buf) - 1] = 0; |
459 | client_version_string = xstrdup(buf); | |
3c0ef626 | 460 | |
461 | /* | |
462 | * Check that the versions match. In future this might accept | |
463 | * several versions and set appropriate flags to handle them. | |
464 | */ | |
465 | if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n", | |
466 | &remote_major, &remote_minor, remote_version) != 3) { | |
467 | s = "Protocol mismatch.\n"; | |
7cac2b65 | 468 | (void) atomicio(vwrite, sock_out, s, strlen(s)); |
3c0ef626 | 469 | close(sock_in); |
470 | close(sock_out); | |
7cac2b65 | 471 | logit("Bad protocol version identification '%.100s' from %s", |
3c0ef626 | 472 | client_version_string, get_remote_ipaddr()); |
540d72c3 | 473 | cleanup_exit(255); |
3c0ef626 | 474 | } |
475 | debug("Client protocol version %d.%d; client software version %.100s", | |
1e608e42 | 476 | remote_major, remote_minor, remote_version); |
fa7499cc | 477 | logit("SSH: Server;Ltype: Version;Remote: %s-%d;Protocol: %d.%d;Client: %.100s", |
478 | get_remote_ipaddr(), get_remote_port(), | |
479 | remote_major, remote_minor, remote_version); | |
3c0ef626 | 480 | |
481 | compat_datafellows(remote_version); | |
482 | ||
d03f4262 | 483 | if (datafellows & SSH_BUG_PROBE) { |
7cac2b65 | 484 | logit("probed from %s with %s. Don't panic.", |
d03f4262 | 485 | get_remote_ipaddr(), client_version_string); |
540d72c3 | 486 | cleanup_exit(255); |
d03f4262 | 487 | } |
488 | ||
3c0ef626 | 489 | if (datafellows & SSH_BUG_SCANNER) { |
7cac2b65 | 490 | logit("scanned from %s with %s. Don't panic.", |
3c0ef626 | 491 | get_remote_ipaddr(), client_version_string); |
540d72c3 | 492 | cleanup_exit(255); |
3c0ef626 | 493 | } |
494 | ||
495 | mismatch = 0; | |
1e608e42 | 496 | switch (remote_major) { |
3c0ef626 | 497 | case 1: |
498 | if (remote_minor == 99) { | |
499 | if (options.protocol & SSH_PROTO_2) | |
500 | enable_compat20(); | |
501 | else | |
502 | mismatch = 1; | |
503 | break; | |
504 | } | |
505 | if (!(options.protocol & SSH_PROTO_1)) { | |
506 | mismatch = 1; | |
507 | break; | |
508 | } | |
509 | if (remote_minor < 3) { | |
510 | packet_disconnect("Your ssh version is too old and " | |
511 | "is no longer supported. Please install a newer version."); | |
512 | } else if (remote_minor == 3) { | |
513 | /* note that this disables agent-forwarding */ | |
514 | enable_compat13(); | |
515 | } | |
516 | break; | |
517 | case 2: | |
518 | if (options.protocol & SSH_PROTO_2) { | |
519 | enable_compat20(); | |
520 | break; | |
521 | } | |
522 | /* FALLTHROUGH */ | |
523 | default: | |
524 | mismatch = 1; | |
525 | break; | |
526 | } | |
527 | chop(server_version_string); | |
528 | debug("Local version string %.200s", server_version_string); | |
529 | ||
530 | if (mismatch) { | |
531 | s = "Protocol major versions differ.\n"; | |
7cac2b65 | 532 | (void) atomicio(vwrite, sock_out, s, strlen(s)); |
3c0ef626 | 533 | close(sock_in); |
534 | close(sock_out); | |
7cac2b65 | 535 | logit("Protocol major versions differ for %s: %.200s vs. %.200s", |
3c0ef626 | 536 | get_remote_ipaddr(), |
537 | server_version_string, client_version_string); | |
540d72c3 | 538 | cleanup_exit(255); |
3c0ef626 | 539 | } |
540 | } | |
541 | ||
3c0ef626 | 542 | /* Destroy the host and server keys. They will no longer be needed. */ |
543 | void | |
544 | destroy_sensitive_data(void) | |
545 | { | |
546 | int i; | |
547 | ||
548 | if (sensitive_data.server_key) { | |
549 | key_free(sensitive_data.server_key); | |
550 | sensitive_data.server_key = NULL; | |
551 | } | |
1e608e42 | 552 | for (i = 0; i < options.num_host_key_files; i++) { |
3c0ef626 | 553 | if (sensitive_data.host_keys[i]) { |
554 | key_free(sensitive_data.host_keys[i]); | |
555 | sensitive_data.host_keys[i] = NULL; | |
556 | } | |
557 | } | |
558 | sensitive_data.ssh1_host_key = NULL; | |
559 | memset(sensitive_data.ssh1_cookie, 0, SSH_SESSION_KEY_LENGTH); | |
560 | } | |
561 | ||
510132b6 | 562 | /* Demote private to public keys for network child */ |
563 | void | |
564 | demote_sensitive_data(void) | |
565 | { | |
566 | Key *tmp; | |
567 | int i; | |
568 | ||
569 | if (sensitive_data.server_key) { | |
570 | tmp = key_demote(sensitive_data.server_key); | |
571 | key_free(sensitive_data.server_key); | |
572 | sensitive_data.server_key = tmp; | |
573 | } | |
574 | ||
575 | for (i = 0; i < options.num_host_key_files; i++) { | |
576 | if (sensitive_data.host_keys[i]) { | |
577 | tmp = key_demote(sensitive_data.host_keys[i]); | |
578 | key_free(sensitive_data.host_keys[i]); | |
579 | sensitive_data.host_keys[i] = tmp; | |
580 | if (tmp->type == KEY_RSA1) | |
581 | sensitive_data.ssh1_host_key = tmp; | |
582 | } | |
583 | } | |
584 | ||
585 | /* We do not clear ssh1_host key and cookie. XXX - Okay Niels? */ | |
586 | } | |
587 | ||
588 | static void | |
589 | privsep_preauth_child(void) | |
590 | { | |
b5afdff5 | 591 | u_int32_t rnd[256]; |
d03f4262 | 592 | gid_t gidset[1]; |
510132b6 | 593 | |
594 | /* Enable challenge-response authentication for privilege separation */ | |
595 | privsep_challenge_enable(); | |
596 | ||
e74dc197 | 597 | arc4random_stir(); |
5156b1a1 | 598 | arc4random_buf(rnd, sizeof(rnd)); |
d03f4262 | 599 | RAND_seed(rnd, sizeof(rnd)); |
510132b6 | 600 | |
601 | /* Demote the private keys to public keys. */ | |
602 | demote_sensitive_data(); | |
603 | ||
d03f4262 | 604 | /* Change our root directory */ |
510132b6 | 605 | if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1) |
606 | fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR, | |
607 | strerror(errno)); | |
608 | if (chdir("/") == -1) | |
609 | fatal("chdir(\"/\"): %s", strerror(errno)); | |
610 | ||
611 | /* Drop our privileges */ | |
30460aeb | 612 | debug3("privsep user:group %u:%u", (u_int)privsep_pw->pw_uid, |
613 | (u_int)privsep_pw->pw_gid); | |
276b07a3 | 614 | #if 0 |
12a403af | 615 | /* XXX not ready, too heavy after chroot */ |
30460aeb | 616 | do_setusercontext(privsep_pw); |
276b07a3 | 617 | #else |
30460aeb | 618 | gidset[0] = privsep_pw->pw_gid; |
276b07a3 | 619 | if (setgroups(1, gidset) < 0) |
620 | fatal("setgroups: %.100s", strerror(errno)); | |
30460aeb | 621 | permanently_set_uid(privsep_pw); |
276b07a3 | 622 | #endif |
510132b6 | 623 | } |
624 | ||
540d72c3 | 625 | static int |
626 | privsep_preauth(Authctxt *authctxt) | |
510132b6 | 627 | { |
510132b6 | 628 | int status; |
629 | pid_t pid; | |
630 | ||
631 | /* Set up unprivileged child process to deal with network data */ | |
632 | pmonitor = monitor_init(); | |
633 | /* Store a pointer to the kex for later rekeying */ | |
634 | pmonitor->m_pkex = &xxx_kex; | |
635 | ||
636 | pid = fork(); | |
637 | if (pid == -1) { | |
638 | fatal("fork of unprivileged child failed"); | |
639 | } else if (pid != 0) { | |
44a053a3 | 640 | debug2("Network child is on pid %ld", (long)pid); |
510132b6 | 641 | |
642 | close(pmonitor->m_recvfd); | |
540d72c3 | 643 | pmonitor->m_pid = pid; |
644 | monitor_child_preauth(authctxt, pmonitor); | |
510132b6 | 645 | close(pmonitor->m_sendfd); |
646 | ||
647 | /* Sync memory */ | |
648 | monitor_sync(pmonitor); | |
649 | ||
650 | /* Wait for the child's exit status */ | |
651 | while (waitpid(pid, &status, 0) < 0) | |
652 | if (errno != EINTR) | |
653 | break; | |
540d72c3 | 654 | return (1); |
510132b6 | 655 | } else { |
656 | /* child */ | |
657 | ||
658 | close(pmonitor->m_sendfd); | |
659 | ||
660 | /* Demote the child */ | |
661 | if (getuid() == 0 || geteuid() == 0) | |
662 | privsep_preauth_child(); | |
663 | setproctitle("%s", "[net]"); | |
664 | } | |
540d72c3 | 665 | return (0); |
510132b6 | 666 | } |
667 | ||
668 | static void | |
669 | privsep_postauth(Authctxt *authctxt) | |
670 | { | |
e74dc197 | 671 | u_int32_t rnd[256]; |
e74dc197 | 672 | |
d03f4262 | 673 | #ifdef DISABLE_FD_PASSING |
276b07a3 | 674 | if (1) { |
675 | #else | |
510132b6 | 676 | if (authctxt->pw->pw_uid == 0 || options.use_login) { |
276b07a3 | 677 | #endif |
510132b6 | 678 | /* File descriptor passing is broken or root login */ |
510132b6 | 679 | use_privsep = 0; |
08822d99 | 680 | goto skip; |
510132b6 | 681 | } |
682 | ||
683 | /* New socket pair */ | |
684 | monitor_reinit(pmonitor); | |
685 | ||
686 | pmonitor->m_pid = fork(); | |
687 | if (pmonitor->m_pid == -1) | |
688 | fatal("fork of unprivileged child failed"); | |
689 | else if (pmonitor->m_pid != 0) { | |
5156b1a1 | 690 | verbose("User child is on pid %ld", (long)pmonitor->m_pid); |
510132b6 | 691 | close(pmonitor->m_recvfd); |
7e82606e | 692 | buffer_clear(&loginmsg); |
510132b6 | 693 | monitor_child_postauth(pmonitor); |
694 | ||
695 | /* NEVERREACHED */ | |
696 | exit(0); | |
697 | } | |
698 | ||
699 | close(pmonitor->m_sendfd); | |
700 | ||
701 | /* Demote the private keys to public keys. */ | |
702 | demote_sensitive_data(); | |
703 | ||
e74dc197 | 704 | arc4random_stir(); |
5156b1a1 | 705 | arc4random_buf(rnd, sizeof(rnd)); |
e74dc197 | 706 | RAND_seed(rnd, sizeof(rnd)); |
707 | ||
510132b6 | 708 | /* Drop privileges */ |
709 | do_setusercontext(authctxt->pw); | |
710 | ||
08822d99 | 711 | skip: |
510132b6 | 712 | /* It is safe now to apply the key state */ |
713 | monitor_apply_keystate(pmonitor); | |
2ce0bfe4 | 714 | |
715 | /* | |
716 | * Tell the packet layer that authentication was successful, since | |
717 | * this information is not part of the key state. | |
718 | */ | |
719 | packet_set_authenticated(); | |
510132b6 | 720 | } |
721 | ||
3c0ef626 | 722 | static char * |
723 | list_hostkey_types(void) | |
724 | { | |
1e608e42 | 725 | Buffer b; |
540d72c3 | 726 | const char *p; |
727 | char *ret; | |
3c0ef626 | 728 | int i; |
1e608e42 | 729 | |
730 | buffer_init(&b); | |
731 | for (i = 0; i < options.num_host_key_files; i++) { | |
3c0ef626 | 732 | Key *key = sensitive_data.host_keys[i]; |
733 | if (key == NULL) | |
734 | continue; | |
1e608e42 | 735 | switch (key->type) { |
3c0ef626 | 736 | case KEY_RSA: |
737 | case KEY_DSA: | |
1e608e42 | 738 | if (buffer_len(&b) > 0) |
739 | buffer_append(&b, ",", 1); | |
740 | p = key_ssh_name(key); | |
741 | buffer_append(&b, p, strlen(p)); | |
3c0ef626 | 742 | break; |
743 | } | |
744 | } | |
1e608e42 | 745 | buffer_append(&b, "\0", 1); |
540d72c3 | 746 | ret = xstrdup(buffer_ptr(&b)); |
1e608e42 | 747 | buffer_free(&b); |
540d72c3 | 748 | debug("list_hostkey_types: %s", ret); |
749 | return ret; | |
3c0ef626 | 750 | } |
751 | ||
510132b6 | 752 | Key * |
3c0ef626 | 753 | get_hostkey_by_type(int type) |
754 | { | |
755 | int i; | |
276b07a3 | 756 | |
1e608e42 | 757 | for (i = 0; i < options.num_host_key_files; i++) { |
3c0ef626 | 758 | Key *key = sensitive_data.host_keys[i]; |
759 | if (key != NULL && key->type == type) | |
760 | return key; | |
761 | } | |
762 | return NULL; | |
763 | } | |
764 | ||
510132b6 | 765 | Key * |
766 | get_hostkey_by_index(int ind) | |
767 | { | |
768 | if (ind < 0 || ind >= options.num_host_key_files) | |
769 | return (NULL); | |
770 | return (sensitive_data.host_keys[ind]); | |
771 | } | |
772 | ||
773 | int | |
774 | get_hostkey_index(Key *key) | |
775 | { | |
776 | int i; | |
276b07a3 | 777 | |
510132b6 | 778 | for (i = 0; i < options.num_host_key_files; i++) { |
779 | if (key == sensitive_data.host_keys[i]) | |
780 | return (i); | |
781 | } | |
782 | return (-1); | |
783 | } | |
784 | ||
3c0ef626 | 785 | /* |
786 | * returns 1 if connection should be dropped, 0 otherwise. | |
787 | * dropping starts at connection #max_startups_begin with a probability | |
788 | * of (max_startups_rate/100). the probability increases linearly until | |
789 | * all connections are dropped for startups > max_startups | |
790 | */ | |
791 | static int | |
792 | drop_connection(int startups) | |
793 | { | |
dfddba3d | 794 | int p, r; |
3c0ef626 | 795 | |
796 | if (startups < options.max_startups_begin) | |
797 | return 0; | |
798 | if (startups >= options.max_startups) | |
799 | return 1; | |
800 | if (options.max_startups_rate == 100) | |
801 | return 1; | |
802 | ||
803 | p = 100 - options.max_startups_rate; | |
804 | p *= startups - options.max_startups_begin; | |
dfddba3d | 805 | p /= options.max_startups - options.max_startups_begin; |
3c0ef626 | 806 | p += options.max_startups_rate; |
5156b1a1 | 807 | r = arc4random_uniform(100); |
3c0ef626 | 808 | |
dfddba3d | 809 | debug("drop_connection: p %d, r %d", p, r); |
3c0ef626 | 810 | return (r < p) ? 1 : 0; |
811 | } | |
812 | ||
1e608e42 | 813 | static void |
814 | usage(void) | |
815 | { | |
12a403af | 816 | fprintf(stderr, "%s, %s\n", |
dfddba3d | 817 | SSH_RELEASE, SSLeay_version(SSLEAY_VERSION)); |
12a403af | 818 | fprintf(stderr, |
5156b1a1 | 819 | "usage: sshd [-46DdeiqTt] [-b bits] [-C connection_spec] [-f config_file]\n" |
820 | " [-g login_grace_time] [-h host_key_file] [-k key_gen_time]\n" | |
821 | " [-o option] [-p port] [-u len]\n" | |
12a403af | 822 | ); |
1e608e42 | 823 | exit(1); |
824 | } | |
3c0ef626 | 825 | |
7e82606e | 826 | static void |
827 | send_rexec_state(int fd, Buffer *conf) | |
828 | { | |
829 | Buffer m; | |
830 | ||
831 | debug3("%s: entering fd = %d config len %d", __func__, fd, | |
832 | buffer_len(conf)); | |
833 | ||
834 | /* | |
835 | * Protocol from reexec master to child: | |
836 | * string configuration | |
837 | * u_int ephemeral_key_follows | |
838 | * bignum e (only if ephemeral_key_follows == 1) | |
839 | * bignum n " | |
840 | * bignum d " | |
841 | * bignum iqmp " | |
842 | * bignum p " | |
843 | * bignum q " | |
08822d99 | 844 | * string rngseed (only if OpenSSL is not self-seeded) |
7e82606e | 845 | */ |
846 | buffer_init(&m); | |
847 | buffer_put_cstring(&m, buffer_ptr(conf)); | |
848 | ||
849 | if (sensitive_data.server_key != NULL && | |
850 | sensitive_data.server_key->type == KEY_RSA1) { | |
851 | buffer_put_int(&m, 1); | |
852 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->e); | |
853 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->n); | |
854 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->d); | |
855 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->iqmp); | |
856 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->p); | |
857 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->q); | |
858 | } else | |
859 | buffer_put_int(&m, 0); | |
860 | ||
08822d99 | 861 | #ifndef OPENSSL_PRNG_ONLY |
862 | rexec_send_rng_seed(&m); | |
863 | #endif | |
864 | ||
7e82606e | 865 | if (ssh_msg_send(fd, 0, &m) == -1) |
866 | fatal("%s: ssh_msg_send failed", __func__); | |
867 | ||
868 | buffer_free(&m); | |
869 | ||
870 | debug3("%s: done", __func__); | |
871 | } | |
872 | ||
873 | static void | |
874 | recv_rexec_state(int fd, Buffer *conf) | |
875 | { | |
876 | Buffer m; | |
877 | char *cp; | |
878 | u_int len; | |
879 | ||
880 | debug3("%s: entering fd = %d", __func__, fd); | |
881 | ||
882 | buffer_init(&m); | |
883 | ||
884 | if (ssh_msg_recv(fd, &m) == -1) | |
885 | fatal("%s: ssh_msg_recv failed", __func__); | |
886 | if (buffer_get_char(&m) != 0) | |
887 | fatal("%s: rexec version mismatch", __func__); | |
888 | ||
889 | cp = buffer_get_string(&m, &len); | |
890 | if (conf != NULL) | |
891 | buffer_append(conf, cp, len + 1); | |
892 | xfree(cp); | |
893 | ||
894 | if (buffer_get_int(&m)) { | |
895 | if (sensitive_data.server_key != NULL) | |
896 | key_free(sensitive_data.server_key); | |
897 | sensitive_data.server_key = key_new_private(KEY_RSA1); | |
898 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->e); | |
899 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->n); | |
900 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->d); | |
901 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->iqmp); | |
902 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->p); | |
903 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->q); | |
904 | rsa_generate_additional_parameters( | |
905 | sensitive_data.server_key->rsa); | |
906 | } | |
08822d99 | 907 | |
908 | #ifndef OPENSSL_PRNG_ONLY | |
909 | rexec_recv_rng_seed(&m); | |
910 | #endif | |
911 | ||
7e82606e | 912 | buffer_free(&m); |
913 | ||
914 | debug3("%s: done", __func__); | |
915 | } | |
916 | ||
30460aeb | 917 | /* Accept a connection from inetd */ |
918 | static void | |
919 | server_accept_inetd(int *sock_in, int *sock_out) | |
920 | { | |
921 | int fd; | |
922 | ||
923 | startup_pipe = -1; | |
924 | if (rexeced_flag) { | |
925 | close(REEXEC_CONFIG_PASS_FD); | |
926 | *sock_in = *sock_out = dup(STDIN_FILENO); | |
927 | if (!debug_flag) { | |
928 | startup_pipe = dup(REEXEC_STARTUP_PIPE_FD); | |
929 | close(REEXEC_STARTUP_PIPE_FD); | |
930 | } | |
931 | } else { | |
932 | *sock_in = dup(STDIN_FILENO); | |
933 | *sock_out = dup(STDOUT_FILENO); | |
934 | } | |
935 | /* | |
936 | * We intentionally do not close the descriptors 0, 1, and 2 | |
937 | * as our code for setting the descriptors won't work if | |
938 | * ttyfd happens to be one of those. | |
939 | */ | |
940 | if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { | |
941 | dup2(fd, STDIN_FILENO); | |
942 | dup2(fd, STDOUT_FILENO); | |
943 | if (fd > STDOUT_FILENO) | |
944 | close(fd); | |
945 | } | |
946 | debug("inetd sockets after dupping: %d, %d", *sock_in, *sock_out); | |
947 | } | |
948 | ||
949 | /* | |
950 | * Listen for TCP connections | |
951 | */ | |
952 | static void | |
953 | server_listen(void) | |
954 | { | |
955 | int ret, listen_sock, on = 1; | |
956 | struct addrinfo *ai; | |
957 | char ntop[NI_MAXHOST], strport[NI_MAXSERV]; | |
2d7c038e | 958 | int socksize; |
959 | int socksizelen = sizeof(int); | |
30460aeb | 960 | |
961 | for (ai = options.listen_addrs; ai; ai = ai->ai_next) { | |
962 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) | |
963 | continue; | |
964 | if (num_listen_socks >= MAX_LISTEN_SOCKS) | |
965 | fatal("Too many listen sockets. " | |
966 | "Enlarge MAX_LISTEN_SOCKS"); | |
967 | if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen, | |
968 | ntop, sizeof(ntop), strport, sizeof(strport), | |
969 | NI_NUMERICHOST|NI_NUMERICSERV)) != 0) { | |
970 | error("getnameinfo failed: %.100s", | |
e74dc197 | 971 | ssh_gai_strerror(ret)); |
30460aeb | 972 | continue; |
973 | } | |
974 | /* Create socket for listening. */ | |
975 | listen_sock = socket(ai->ai_family, ai->ai_socktype, | |
976 | ai->ai_protocol); | |
977 | if (listen_sock < 0) { | |
978 | /* kernel may not support ipv6 */ | |
979 | verbose("socket: %.100s", strerror(errno)); | |
980 | continue; | |
981 | } | |
982 | if (set_nonblock(listen_sock) == -1) { | |
983 | close(listen_sock); | |
984 | continue; | |
985 | } | |
986 | /* | |
987 | * Set socket options. | |
988 | * Allow local port reuse in TIME_WAIT. | |
989 | */ | |
990 | if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR, | |
991 | &on, sizeof(on)) == -1) | |
992 | error("setsockopt SO_REUSEADDR: %s", strerror(errno)); | |
993 | ||
e74dc197 | 994 | #ifdef IPV6_V6ONLY |
995 | /* Only communicate in IPv6 over AF_INET6 sockets. */ | |
996 | if (ai->ai_family == AF_INET6) { | |
997 | if (setsockopt(listen_sock, IPPROTO_IPV6, IPV6_V6ONLY, | |
998 | &on, sizeof(on)) == -1) | |
999 | error("setsockopt IPV6_V6ONLY: %s", | |
1000 | strerror(errno)); | |
1001 | } | |
1002 | #endif | |
1003 | ||
30460aeb | 1004 | debug("Bind to port %s on %s.", strport, ntop); |
6df46d40 | 1005 | |
2d7c038e | 1006 | getsockopt(listen_sock, SOL_SOCKET, SO_RCVBUF, |
1007 | &socksize, &socksizelen); | |
1008 | debug("Server TCP RWIN socket size: %d", socksize); | |
1009 | debug("HPN Buffer Size: %d", options.hpn_buffer_size); | |
30460aeb | 1010 | |
1011 | /* Bind the socket to the desired port. */ | |
1012 | if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) { | |
1013 | error("Bind to port %s on %s failed: %.200s.", | |
1014 | strport, ntop, strerror(errno)); | |
1015 | close(listen_sock); | |
1016 | continue; | |
1017 | } | |
1018 | listen_socks[num_listen_socks] = listen_sock; | |
1019 | num_listen_socks++; | |
1020 | ||
1021 | /* Start listening on the port. */ | |
1022 | if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0) | |
1023 | fatal("listen on [%s]:%s: %.100s", | |
1024 | ntop, strport, strerror(errno)); | |
1025 | logit("Server listening on %s port %s.", ntop, strport); | |
1026 | } | |
1027 | freeaddrinfo(options.listen_addrs); | |
1028 | ||
1029 | if (!num_listen_socks) | |
1030 | fatal("Cannot bind any address."); | |
1031 | } | |
1032 | ||
1033 | /* | |
1034 | * The main TCP accept loop. Note that, for the non-debug case, returns | |
1035 | * from this function are in a forked subprocess. | |
1036 | */ | |
1037 | static void | |
1038 | server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s) | |
1039 | { | |
1040 | fd_set *fdset; | |
1041 | int i, j, ret, maxfd; | |
1042 | int key_used = 0, startups = 0; | |
1043 | int startup_p[2] = { -1 , -1 }; | |
1044 | struct sockaddr_storage from; | |
1045 | socklen_t fromlen; | |
1046 | pid_t pid; | |
1047 | ||
1048 | /* setup fd set for accept */ | |
1049 | fdset = NULL; | |
1050 | maxfd = 0; | |
1051 | for (i = 0; i < num_listen_socks; i++) | |
1052 | if (listen_socks[i] > maxfd) | |
1053 | maxfd = listen_socks[i]; | |
1054 | /* pipes connected to unauthenticated childs */ | |
1055 | startup_pipes = xcalloc(options.max_startups, sizeof(int)); | |
1056 | for (i = 0; i < options.max_startups; i++) | |
1057 | startup_pipes[i] = -1; | |
1058 | ||
1059 | /* | |
1060 | * Stay listening for connections until the system crashes or | |
1061 | * the daemon is killed with a signal. | |
1062 | */ | |
1063 | for (;;) { | |
1064 | if (received_sighup) | |
1065 | sighup_restart(); | |
1066 | if (fdset != NULL) | |
1067 | xfree(fdset); | |
1068 | fdset = (fd_set *)xcalloc(howmany(maxfd + 1, NFDBITS), | |
1069 | sizeof(fd_mask)); | |
1070 | ||
1071 | for (i = 0; i < num_listen_socks; i++) | |
1072 | FD_SET(listen_socks[i], fdset); | |
1073 | for (i = 0; i < options.max_startups; i++) | |
1074 | if (startup_pipes[i] != -1) | |
1075 | FD_SET(startup_pipes[i], fdset); | |
1076 | ||
1077 | /* Wait in select until there is a connection. */ | |
1078 | ret = select(maxfd+1, fdset, NULL, NULL, NULL); | |
1079 | if (ret < 0 && errno != EINTR) | |
1080 | error("select: %.100s", strerror(errno)); | |
1081 | if (received_sigterm) { | |
1082 | logit("Received signal %d; terminating.", | |
1083 | (int) received_sigterm); | |
1084 | close_listen_socks(); | |
1085 | unlink(options.pid_file); | |
1086 | exit(255); | |
1087 | } | |
1088 | if (key_used && key_do_regen) { | |
1089 | generate_ephemeral_server_key(); | |
1090 | key_used = 0; | |
1091 | key_do_regen = 0; | |
1092 | } | |
1093 | if (ret < 0) | |
1094 | continue; | |
1095 | ||
1096 | for (i = 0; i < options.max_startups; i++) | |
1097 | if (startup_pipes[i] != -1 && | |
1098 | FD_ISSET(startup_pipes[i], fdset)) { | |
1099 | /* | |
1100 | * the read end of the pipe is ready | |
1101 | * if the child has closed the pipe | |
1102 | * after successful authentication | |
1103 | * or if the child has died | |
1104 | */ | |
1105 | close(startup_pipes[i]); | |
1106 | startup_pipes[i] = -1; | |
1107 | startups--; | |
1108 | } | |
1109 | for (i = 0; i < num_listen_socks; i++) { | |
1110 | if (!FD_ISSET(listen_socks[i], fdset)) | |
1111 | continue; | |
1112 | fromlen = sizeof(from); | |
1113 | *newsock = accept(listen_socks[i], | |
1114 | (struct sockaddr *)&from, &fromlen); | |
1115 | if (*newsock < 0) { | |
5156b1a1 | 1116 | if (errno != EINTR && errno != EAGAIN && |
1117 | errno != EWOULDBLOCK) | |
30460aeb | 1118 | error("accept: %.100s", strerror(errno)); |
1119 | continue; | |
1120 | } | |
1121 | if (unset_nonblock(*newsock) == -1) { | |
1122 | close(*newsock); | |
1123 | continue; | |
1124 | } | |
1125 | if (drop_connection(startups) == 1) { | |
1126 | debug("drop connection #%d", startups); | |
1127 | close(*newsock); | |
1128 | continue; | |
1129 | } | |
1130 | if (pipe(startup_p) == -1) { | |
1131 | close(*newsock); | |
1132 | continue; | |
1133 | } | |
1134 | ||
1135 | if (rexec_flag && socketpair(AF_UNIX, | |
1136 | SOCK_STREAM, 0, config_s) == -1) { | |
1137 | error("reexec socketpair: %s", | |
1138 | strerror(errno)); | |
1139 | close(*newsock); | |
1140 | close(startup_p[0]); | |
1141 | close(startup_p[1]); | |
1142 | continue; | |
1143 | } | |
1144 | ||
1145 | for (j = 0; j < options.max_startups; j++) | |
1146 | if (startup_pipes[j] == -1) { | |
1147 | startup_pipes[j] = startup_p[0]; | |
1148 | if (maxfd < startup_p[0]) | |
1149 | maxfd = startup_p[0]; | |
1150 | startups++; | |
1151 | break; | |
1152 | } | |
1153 | ||
1154 | /* | |
1155 | * Got connection. Fork a child to handle it, unless | |
1156 | * we are in debugging mode. | |
1157 | */ | |
1158 | if (debug_flag) { | |
1159 | /* | |
1160 | * In debugging mode. Close the listening | |
1161 | * socket, and start processing the | |
1162 | * connection without forking. | |
1163 | */ | |
1164 | debug("Server will not fork when running in debugging mode."); | |
1165 | close_listen_socks(); | |
1166 | *sock_in = *newsock; | |
1167 | *sock_out = *newsock; | |
1168 | close(startup_p[0]); | |
1169 | close(startup_p[1]); | |
1170 | startup_pipe = -1; | |
1171 | pid = getpid(); | |
1172 | if (rexec_flag) { | |
1173 | send_rexec_state(config_s[0], | |
1174 | &cfg); | |
1175 | close(config_s[0]); | |
1176 | } | |
1177 | break; | |
1178 | } | |
1179 | ||
1180 | /* | |
1181 | * Normal production daemon. Fork, and have | |
1182 | * the child process the connection. The | |
1183 | * parent continues listening. | |
1184 | */ | |
1185 | platform_pre_fork(); | |
1186 | if ((pid = fork()) == 0) { | |
1187 | /* | |
1188 | * Child. Close the listening and | |
1189 | * max_startup sockets. Start using | |
1190 | * the accepted socket. Reinitialize | |
1191 | * logging (since our pid has changed). | |
1192 | * We break out of the loop to handle | |
1193 | * the connection. | |
1194 | */ | |
1195 | platform_post_fork_child(); | |
1196 | startup_pipe = startup_p[1]; | |
1197 | close_startup_pipes(); | |
1198 | close_listen_socks(); | |
1199 | *sock_in = *newsock; | |
1200 | *sock_out = *newsock; | |
1201 | log_init(__progname, | |
1202 | options.log_level, | |
1203 | options.log_facility, | |
1204 | log_stderr); | |
1205 | if (rexec_flag) | |
1206 | close(config_s[0]); | |
1207 | break; | |
1208 | } | |
1209 | ||
1210 | /* Parent. Stay in the loop. */ | |
1211 | platform_post_fork_parent(pid); | |
1212 | if (pid < 0) | |
1213 | error("fork: %.100s", strerror(errno)); | |
1214 | else | |
1215 | debug("Forked child %ld.", (long)pid); | |
1216 | ||
1217 | close(startup_p[1]); | |
1218 | ||
1219 | if (rexec_flag) { | |
1220 | send_rexec_state(config_s[0], &cfg); | |
1221 | close(config_s[0]); | |
1222 | close(config_s[1]); | |
1223 | } | |
1224 | ||
1225 | /* | |
1226 | * Mark that the key has been used (it | |
1227 | * was "given" to the child). | |
1228 | */ | |
1229 | if ((options.protocol & SSH_PROTO_1) && | |
1230 | key_used == 0) { | |
1231 | /* Schedule server key regeneration alarm. */ | |
1232 | signal(SIGALRM, key_regeneration_alarm); | |
1233 | alarm(options.key_regeneration_time); | |
1234 | key_used = 1; | |
1235 | } | |
1236 | ||
1237 | close(*newsock); | |
1238 | ||
1239 | /* | |
1240 | * Ensure that our random state differs | |
1241 | * from that of the child | |
1242 | */ | |
1243 | arc4random_stir(); | |
1244 | } | |
1245 | ||
1246 | /* child process check (or debug mode) */ | |
1247 | if (num_listen_socks < 0) | |
1248 | break; | |
1249 | } | |
1250 | } | |
1251 | ||
1252 | ||
3c0ef626 | 1253 | /* |
1254 | * Main program for the daemon. | |
1255 | */ | |
1256 | int | |
1257 | main(int ac, char **av) | |
1258 | { | |
1259 | extern char *optarg; | |
1260 | extern int optind; | |
30460aeb | 1261 | int opt, i, on = 1; |
7e82606e | 1262 | int sock_in = -1, sock_out = -1, newsock = -1; |
3c0ef626 | 1263 | const char *remote_ip; |
5156b1a1 | 1264 | char *test_user = NULL, *test_host = NULL, *test_addr = NULL; |
3c0ef626 | 1265 | int remote_port; |
5156b1a1 | 1266 | char *line, *p, *cp; |
30460aeb | 1267 | int config_s[2] = { -1 , -1 }; |
5156b1a1 | 1268 | u_int64_t ibytes, obytes; |
1269 | mode_t new_umask; | |
3c0ef626 | 1270 | Key *key; |
540d72c3 | 1271 | Authctxt *authctxt; |
3c0ef626 | 1272 | |
510132b6 | 1273 | #ifdef HAVE_SECUREWARE |
1274 | (void)set_auth_parameters(ac, av); | |
1275 | #endif | |
7cac2b65 | 1276 | __progname = ssh_get_progname(av[0]); |
3c0ef626 | 1277 | init_rng(); |
1278 | ||
bfe49944 | 1279 | /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */ |
3c0ef626 | 1280 | saved_argc = ac; |
7e82606e | 1281 | rexec_argc = ac; |
30460aeb | 1282 | saved_argv = xcalloc(ac + 1, sizeof(*saved_argv)); |
bfe49944 | 1283 | for (i = 0; i < ac; i++) |
1284 | saved_argv[i] = xstrdup(av[i]); | |
7cac2b65 | 1285 | saved_argv[i] = NULL; |
bfe49944 | 1286 | |
1287 | #ifndef HAVE_SETPROCTITLE | |
1288 | /* Prepare for later setproctitle emulation */ | |
1289 | compat_init_setproctitle(ac, av); | |
7cac2b65 | 1290 | av = saved_argv; |
bfe49944 | 1291 | #endif |
3c0ef626 | 1292 | |
12a403af | 1293 | if (geteuid() == 0 && setgroups(0, NULL) == -1) |
1294 | debug("setgroups(): %.200s", strerror(errno)); | |
1295 | ||
08822d99 | 1296 | /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ |
1297 | sanitise_stdfd(); | |
1298 | ||
3c0ef626 | 1299 | /* Initialize configuration options to their default values. */ |
1300 | initialize_server_options(&options); | |
1301 | ||
1302 | /* Parse command-line arguments. */ | |
5156b1a1 | 1303 | while ((opt = getopt(ac, av, "f:p:b:k:h:g:u:o:C:dDeiqrtQRT46")) != -1) { |
3c0ef626 | 1304 | switch (opt) { |
1305 | case '4': | |
dfddba3d | 1306 | options.address_family = AF_INET; |
3c0ef626 | 1307 | break; |
1308 | case '6': | |
dfddba3d | 1309 | options.address_family = AF_INET6; |
3c0ef626 | 1310 | break; |
1311 | case 'f': | |
1312 | config_file_name = optarg; | |
1313 | break; | |
1314 | case 'd': | |
7cac2b65 | 1315 | if (debug_flag == 0) { |
3c0ef626 | 1316 | debug_flag = 1; |
1317 | options.log_level = SYSLOG_LEVEL_DEBUG1; | |
7cac2b65 | 1318 | } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) |
3c0ef626 | 1319 | options.log_level++; |
3c0ef626 | 1320 | break; |
1321 | case 'D': | |
1322 | no_daemon_flag = 1; | |
1323 | break; | |
1324 | case 'e': | |
1325 | log_stderr = 1; | |
1326 | break; | |
1327 | case 'i': | |
1328 | inetd_flag = 1; | |
1329 | break; | |
7e82606e | 1330 | case 'r': |
1331 | rexec_flag = 0; | |
1332 | break; | |
1333 | case 'R': | |
1334 | rexeced_flag = 1; | |
1335 | inetd_flag = 1; | |
1336 | break; | |
3c0ef626 | 1337 | case 'Q': |
1338 | /* ignored */ | |
1339 | break; | |
1340 | case 'q': | |
1341 | options.log_level = SYSLOG_LEVEL_QUIET; | |
1342 | break; | |
1343 | case 'b': | |
30460aeb | 1344 | options.server_key_bits = (int)strtonum(optarg, 256, |
1345 | 32768, NULL); | |
3c0ef626 | 1346 | break; |
1347 | case 'p': | |
1348 | options.ports_from_cmdline = 1; | |
1349 | if (options.num_ports >= MAX_PORTS) { | |
1350 | fprintf(stderr, "too many ports.\n"); | |
1351 | exit(1); | |
1352 | } | |
1353 | options.ports[options.num_ports++] = a2port(optarg); | |
5262cbfb | 1354 | if (options.ports[options.num_ports-1] <= 0) { |
3c0ef626 | 1355 | fprintf(stderr, "Bad port number.\n"); |
1356 | exit(1); | |
1357 | } | |
1358 | break; | |
1359 | case 'g': | |
1360 | if ((options.login_grace_time = convtime(optarg)) == -1) { | |
1361 | fprintf(stderr, "Invalid login grace time.\n"); | |
1362 | exit(1); | |
1363 | } | |
1364 | break; | |
1365 | case 'k': | |
1366 | if ((options.key_regeneration_time = convtime(optarg)) == -1) { | |
1367 | fprintf(stderr, "Invalid key regeneration interval.\n"); | |
1368 | exit(1); | |
1369 | } | |
1370 | break; | |
1371 | case 'h': | |
1372 | if (options.num_host_key_files >= MAX_HOSTKEYS) { | |
1373 | fprintf(stderr, "too many host keys.\n"); | |
1374 | exit(1); | |
1375 | } | |
1376 | options.host_key_files[options.num_host_key_files++] = optarg; | |
1377 | break; | |
3c0ef626 | 1378 | case 't': |
1379 | test_flag = 1; | |
1380 | break; | |
5156b1a1 | 1381 | case 'T': |
1382 | test_flag = 2; | |
1383 | break; | |
1384 | case 'C': | |
1385 | cp = optarg; | |
1386 | while ((p = strsep(&cp, ",")) && *p != '\0') { | |
1387 | if (strncmp(p, "addr=", 5) == 0) | |
1388 | test_addr = xstrdup(p + 5); | |
1389 | else if (strncmp(p, "host=", 5) == 0) | |
1390 | test_host = xstrdup(p + 5); | |
1391 | else if (strncmp(p, "user=", 5) == 0) | |
1392 | test_user = xstrdup(p + 5); | |
1393 | else { | |
1394 | fprintf(stderr, "Invalid test " | |
1395 | "mode specification %s\n", p); | |
1396 | exit(1); | |
1397 | } | |
1398 | } | |
1399 | break; | |
3c0ef626 | 1400 | case 'u': |
30460aeb | 1401 | utmp_len = (u_int)strtonum(optarg, 0, MAXHOSTNAMELEN+1, NULL); |
d03f4262 | 1402 | if (utmp_len > MAXHOSTNAMELEN) { |
1403 | fprintf(stderr, "Invalid utmp length.\n"); | |
1404 | exit(1); | |
1405 | } | |
3c0ef626 | 1406 | break; |
1e608e42 | 1407 | case 'o': |
540d72c3 | 1408 | line = xstrdup(optarg); |
1409 | if (process_server_config_line(&options, line, | |
30460aeb | 1410 | "command-line", 0, NULL, NULL, NULL, NULL) != 0) |
1e608e42 | 1411 | exit(1); |
540d72c3 | 1412 | xfree(line); |
1e608e42 | 1413 | break; |
3c0ef626 | 1414 | case '?': |
1415 | default: | |
1e608e42 | 1416 | usage(); |
1417 | break; | |
3c0ef626 | 1418 | } |
1419 | } | |
7e82606e | 1420 | if (rexeced_flag || inetd_flag) |
1421 | rexec_flag = 0; | |
e74dc197 | 1422 | if (!test_flag && (rexec_flag && (av[0] == NULL || *av[0] != '/'))) |
7e82606e | 1423 | fatal("sshd re-exec requires execution with an absolute path"); |
1424 | if (rexeced_flag) | |
1425 | closefrom(REEXEC_MIN_FREE_FD); | |
1426 | else | |
1427 | closefrom(REEXEC_DEVCRYPTO_RESERVED_FD); | |
1428 | ||
3c0ef626 | 1429 | SSLeay_add_all_algorithms(); |
3c0ef626 | 1430 | |
1431 | /* | |
1432 | * Force logging to stderr until we have loaded the private host | |
1433 | * key (unless started from inetd) | |
1434 | */ | |
1435 | log_init(__progname, | |
1e608e42 | 1436 | options.log_level == SYSLOG_LEVEL_NOT_SET ? |
1437 | SYSLOG_LEVEL_INFO : options.log_level, | |
1438 | options.log_facility == SYSLOG_FACILITY_NOT_SET ? | |
1439 | SYSLOG_FACILITY_AUTH : options.log_facility, | |
bfe49944 | 1440 | log_stderr || !inetd_flag); |
3c0ef626 | 1441 | |
12a403af | 1442 | /* |
1443 | * Unset KRB5CCNAME, otherwise the user's session may inherit it from | |
1444 | * root's environment | |
2ce0bfe4 | 1445 | */ |
dfddba3d | 1446 | if (getenv("KRB5CCNAME") != NULL) |
1447 | unsetenv("KRB5CCNAME"); | |
1448 | ||
d03f4262 | 1449 | #ifdef _UNICOS |
7e82606e | 1450 | /* Cray can define user privs drop all privs now! |
3c0ef626 | 1451 | * Not needed on PRIV_SU systems! |
1452 | */ | |
1453 | drop_cray_privs(); | |
1454 | #endif | |
1455 | ||
7e82606e | 1456 | sensitive_data.server_key = NULL; |
1457 | sensitive_data.ssh1_host_key = NULL; | |
1458 | sensitive_data.have_ssh1_key = 0; | |
1459 | sensitive_data.have_ssh2_key = 0; | |
1460 | ||
5156b1a1 | 1461 | /* |
1462 | * If we're doing an extended config test, make sure we have all of | |
1463 | * the parameters we need. If we're not doing an extended test, | |
1464 | * do not silently ignore connection test params. | |
1465 | */ | |
1466 | if (test_flag >= 2 && | |
1467 | (test_user != NULL || test_host != NULL || test_addr != NULL) | |
1468 | && (test_user == NULL || test_host == NULL || test_addr == NULL)) | |
1469 | fatal("user, host and addr are all required when testing " | |
1470 | "Match configs"); | |
1471 | if (test_flag < 2 && (test_user != NULL || test_host != NULL || | |
1472 | test_addr != NULL)) | |
1473 | fatal("Config test connection parameter (-C) provided without " | |
1474 | "test mode (-T)"); | |
1475 | ||
7e82606e | 1476 | /* Fetch our configuration */ |
1477 | buffer_init(&cfg); | |
1478 | if (rexeced_flag) | |
1479 | recv_rexec_state(REEXEC_CONFIG_PASS_FD, &cfg); | |
1480 | else | |
1481 | load_server_config(config_file_name, &cfg); | |
1482 | ||
30460aeb | 1483 | parse_server_config(&options, rexeced_flag ? "rexec" : config_file_name, |
1484 | &cfg, NULL, NULL, NULL); | |
3c0ef626 | 1485 | |
08822d99 | 1486 | seed_rng(); |
1487 | ||
3c0ef626 | 1488 | /* Fill in default values for those options not explicitly set. */ |
1489 | fill_default_server_options(&options); | |
1490 | ||
fa0f0f45 | 1491 | /* challenge-response is implemented via keyboard interactive */ |
1492 | if (options.challenge_response_authentication) | |
1493 | options.kbd_interactive_authentication = 1; | |
1494 | ||
dfddba3d | 1495 | /* set default channel AF */ |
1496 | channel_set_af(options.address_family); | |
1497 | ||
3c0ef626 | 1498 | /* Check that there are no remaining arguments. */ |
1499 | if (optind < ac) { | |
1500 | fprintf(stderr, "Extra argument %s.\n", av[optind]); | |
1501 | exit(1); | |
1502 | } | |
1503 | ||
dfddba3d | 1504 | debug("sshd version %.100s", SSH_RELEASE); |
3c0ef626 | 1505 | |
240debe0 | 1506 | /* Store privilege separation user for later use if required. */ |
1507 | if ((privsep_pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) { | |
1508 | if (use_privsep || options.kerberos_authentication) | |
1509 | fatal("Privilege separation user %s does not exist", | |
1510 | SSH_PRIVSEP_USER); | |
1511 | } else { | |
1512 | memset(privsep_pw->pw_passwd, 0, strlen(privsep_pw->pw_passwd)); | |
1513 | privsep_pw = pwcopy(privsep_pw); | |
1514 | xfree(privsep_pw->pw_passwd); | |
1515 | privsep_pw->pw_passwd = xstrdup("*"); | |
1516 | } | |
30460aeb | 1517 | endpwent(); |
1518 | ||
3c0ef626 | 1519 | /* load private host keys */ |
30460aeb | 1520 | sensitive_data.host_keys = xcalloc(options.num_host_key_files, |
d03f4262 | 1521 | sizeof(Key *)); |
1e608e42 | 1522 | for (i = 0; i < options.num_host_key_files; i++) |
3c0ef626 | 1523 | sensitive_data.host_keys[i] = NULL; |
3c0ef626 | 1524 | |
1e608e42 | 1525 | for (i = 0; i < options.num_host_key_files; i++) { |
3c0ef626 | 1526 | key = key_load_private(options.host_key_files[i], "", NULL); |
1527 | sensitive_data.host_keys[i] = key; | |
1528 | if (key == NULL) { | |
1529 | error("Could not load host key: %s", | |
1530 | options.host_key_files[i]); | |
1531 | sensitive_data.host_keys[i] = NULL; | |
1532 | continue; | |
1533 | } | |
1e608e42 | 1534 | switch (key->type) { |
3c0ef626 | 1535 | case KEY_RSA1: |
1536 | sensitive_data.ssh1_host_key = key; | |
1537 | sensitive_data.have_ssh1_key = 1; | |
1538 | break; | |
1539 | case KEY_RSA: | |
1540 | case KEY_DSA: | |
1541 | sensitive_data.have_ssh2_key = 1; | |
1542 | break; | |
1543 | } | |
1544 | debug("private host key: #%d type %d %s", i, key->type, | |
1545 | key_type(key)); | |
1546 | } | |
1547 | if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) { | |
7cac2b65 | 1548 | logit("Disabling protocol version 1. Could not load host key"); |
3c0ef626 | 1549 | options.protocol &= ~SSH_PROTO_1; |
1550 | } | |
5598e598 | 1551 | #ifndef GSSAPI |
1552 | /* The GSSAPI key exchange can run without a host key */ | |
3c0ef626 | 1553 | if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) { |
7cac2b65 | 1554 | logit("Disabling protocol version 2. Could not load host key"); |
3c0ef626 | 1555 | options.protocol &= ~SSH_PROTO_2; |
1556 | } | |
5598e598 | 1557 | #endif |
3c0ef626 | 1558 | if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) { |
7cac2b65 | 1559 | logit("sshd: no hostkeys available -- exiting."); |
3c0ef626 | 1560 | exit(1); |
1561 | } | |
1562 | ||
1563 | /* Check certain values for sanity. */ | |
1564 | if (options.protocol & SSH_PROTO_1) { | |
1565 | if (options.server_key_bits < 512 || | |
1566 | options.server_key_bits > 32768) { | |
1567 | fprintf(stderr, "Bad server key size.\n"); | |
1568 | exit(1); | |
1569 | } | |
1570 | /* | |
1571 | * Check that server and host key lengths differ sufficiently. This | |
1572 | * is necessary to make double encryption work with rsaref. Oh, I | |
1573 | * hate software patents. I dont know if this can go? Niels | |
1574 | */ | |
1575 | if (options.server_key_bits > | |
276b07a3 | 1576 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) - |
1577 | SSH_KEY_BITS_RESERVED && options.server_key_bits < | |
1578 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + | |
1579 | SSH_KEY_BITS_RESERVED) { | |
3c0ef626 | 1580 | options.server_key_bits = |
276b07a3 | 1581 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + |
1582 | SSH_KEY_BITS_RESERVED; | |
3c0ef626 | 1583 | debug("Forcing server key to %d bits to make it differ from host key.", |
1584 | options.server_key_bits); | |
1585 | } | |
1586 | } | |
1587 | ||
44a053a3 | 1588 | if (use_privsep) { |
44a053a3 | 1589 | struct stat st; |
1590 | ||
44a053a3 | 1591 | if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) || |
1592 | (S_ISDIR(st.st_mode) == 0)) | |
1593 | fatal("Missing privilege separation directory: %s", | |
1594 | _PATH_PRIVSEP_CHROOT_DIR); | |
d03f4262 | 1595 | |
1596 | #ifdef HAVE_CYGWIN | |
1597 | if (check_ntsec(_PATH_PRIVSEP_CHROOT_DIR) && | |
1598 | (st.st_uid != getuid () || | |
1599 | (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)) | |
1600 | #else | |
276b07a3 | 1601 | if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0) |
d03f4262 | 1602 | #endif |
bfe49944 | 1603 | fatal("%s must be owned by root and not group or " |
1604 | "world-writable.", _PATH_PRIVSEP_CHROOT_DIR); | |
44a053a3 | 1605 | } |
1606 | ||
5156b1a1 | 1607 | if (test_flag > 1) { |
1608 | if (test_user != NULL && test_addr != NULL && test_host != NULL) | |
1609 | parse_server_match_config(&options, test_user, | |
1610 | test_host, test_addr); | |
1611 | dump_config(&options); | |
1612 | } | |
1613 | ||
3c0ef626 | 1614 | /* Configuration looks good, so exit if in test mode. */ |
1615 | if (test_flag) | |
1616 | exit(0); | |
1617 | ||
510132b6 | 1618 | /* |
1619 | * Clear out any supplemental groups we may have inherited. This | |
1620 | * prevents inadvertent creation of files with bad modes (in the | |
540d72c3 | 1621 | * portable version at least, it's certainly possible for PAM |
1622 | * to create a file, and we can't control the code in every | |
510132b6 | 1623 | * module which might be used). |
1624 | */ | |
1625 | if (setgroups(0, NULL) < 0) | |
1626 | debug("setgroups() failed: %.200s", strerror(errno)); | |
3c0ef626 | 1627 | |
7e82606e | 1628 | if (rexec_flag) { |
30460aeb | 1629 | rexec_argv = xcalloc(rexec_argc + 2, sizeof(char *)); |
7e82606e | 1630 | for (i = 0; i < rexec_argc; i++) { |
1631 | debug("rexec_argv[%d]='%s'", i, saved_argv[i]); | |
1632 | rexec_argv[i] = saved_argv[i]; | |
1633 | } | |
1634 | rexec_argv[rexec_argc] = "-R"; | |
1635 | rexec_argv[rexec_argc + 1] = NULL; | |
1636 | } | |
1637 | ||
5156b1a1 | 1638 | /* Ensure that umask disallows at least group and world write */ |
1639 | new_umask = umask(0077) | 0022; | |
1640 | (void) umask(new_umask); | |
1641 | ||
3c0ef626 | 1642 | /* Initialize the log (it is reinitialized below in case we forked). */ |
dfddba3d | 1643 | if (debug_flag && (!inetd_flag || rexeced_flag)) |
3c0ef626 | 1644 | log_stderr = 1; |
1645 | log_init(__progname, options.log_level, options.log_facility, log_stderr); | |
1646 | ||
1647 | /* | |
1648 | * If not in debugging mode, and not started from inetd, disconnect | |
1649 | * from the controlling terminal, and fork. The original process | |
1650 | * exits. | |
1651 | */ | |
1652 | if (!(debug_flag || inetd_flag || no_daemon_flag)) { | |
1653 | #ifdef TIOCNOTTY | |
1654 | int fd; | |
1655 | #endif /* TIOCNOTTY */ | |
1656 | if (daemon(0, 0) < 0) | |
1657 | fatal("daemon() failed: %.200s", strerror(errno)); | |
1658 | ||
1659 | /* Disconnect from the controlling tty. */ | |
1660 | #ifdef TIOCNOTTY | |
1661 | fd = open(_PATH_TTY, O_RDWR | O_NOCTTY); | |
1662 | if (fd >= 0) { | |
1663 | (void) ioctl(fd, TIOCNOTTY, NULL); | |
1664 | close(fd); | |
1665 | } | |
1666 | #endif /* TIOCNOTTY */ | |
1667 | } | |
1668 | /* Reinitialize the log (because of the fork above). */ | |
1669 | log_init(__progname, options.log_level, options.log_facility, log_stderr); | |
1670 | ||
1671 | /* Initialize the random number generator. */ | |
1672 | arc4random_stir(); | |
1673 | ||
1674 | /* Chdir to the root directory so that the current disk can be | |
1675 | unmounted if desired. */ | |
1676 | chdir("/"); | |
1e608e42 | 1677 | |
3c0ef626 | 1678 | /* ignore SIGPIPE */ |
1679 | signal(SIGPIPE, SIG_IGN); | |
1680 | ||
30460aeb | 1681 | /* Get a connection, either from inetd or a listening TCP socket */ |
3c0ef626 | 1682 | if (inetd_flag) { |
30460aeb | 1683 | server_accept_inetd(&sock_in, &sock_out); |
3c0ef626 | 1684 | } else { |
30460aeb | 1685 | server_listen(); |
3c0ef626 | 1686 | |
1687 | if (options.protocol & SSH_PROTO_1) | |
1688 | generate_ephemeral_server_key(); | |
1689 | ||
3c0ef626 | 1690 | signal(SIGHUP, sighup_handler); |
30460aeb | 1691 | signal(SIGCHLD, main_sigchld_handler); |
3c0ef626 | 1692 | signal(SIGTERM, sigterm_handler); |
1693 | signal(SIGQUIT, sigterm_handler); | |
1694 | ||
30460aeb | 1695 | /* |
1696 | * Write out the pid file after the sigterm handler | |
1697 | * is setup and the listen sockets are bound | |
1698 | */ | |
3c0ef626 | 1699 | if (!debug_flag) { |
30460aeb | 1700 | FILE *f = fopen(options.pid_file, "w"); |
1701 | ||
7cac2b65 | 1702 | if (f == NULL) { |
1703 | error("Couldn't create pid file \"%s\": %s", | |
1704 | options.pid_file, strerror(errno)); | |
1705 | } else { | |
44a053a3 | 1706 | fprintf(f, "%ld\n", (long) getpid()); |
3c0ef626 | 1707 | fclose(f); |
1708 | } | |
1709 | } | |
1710 | ||
30460aeb | 1711 | /* Accept a connection and return in a forked child */ |
1712 | server_accept_loop(&sock_in, &sock_out, | |
1713 | &newsock, config_s); | |
3c0ef626 | 1714 | } |
1715 | ||
1716 | /* This is the child processing a new connection. */ | |
12a403af | 1717 | setproctitle("%s", "[accepted]"); |
3c0ef626 | 1718 | |
510132b6 | 1719 | /* |
1720 | * Create a new session and process group since the 4.4BSD | |
1721 | * setlogin() affects the entire process group. We don't | |
1722 | * want the child to be able to affect the parent. | |
1723 | */ | |
7cac2b65 | 1724 | #if !defined(SSHD_ACQUIRES_CTTY) |
bfe49944 | 1725 | /* |
7cac2b65 | 1726 | * If setsid is called, on some platforms sshd will later acquire a |
1727 | * controlling terminal which will result in "could not set | |
1728 | * controlling tty" errors. | |
bfe49944 | 1729 | */ |
276b07a3 | 1730 | if (!debug_flag && !inetd_flag && setsid() < 0) |
510132b6 | 1731 | error("setsid: %.100s", strerror(errno)); |
1732 | #endif | |
1733 | ||
7e82606e | 1734 | if (rexec_flag) { |
1735 | int fd; | |
1736 | ||
1737 | debug("rexec start in %d out %d newsock %d pipe %d sock %d", | |
1738 | sock_in, sock_out, newsock, startup_pipe, config_s[0]); | |
1739 | dup2(newsock, STDIN_FILENO); | |
1740 | dup2(STDIN_FILENO, STDOUT_FILENO); | |
1741 | if (startup_pipe == -1) | |
1742 | close(REEXEC_STARTUP_PIPE_FD); | |
1743 | else | |
1744 | dup2(startup_pipe, REEXEC_STARTUP_PIPE_FD); | |
1745 | ||
1746 | dup2(config_s[1], REEXEC_CONFIG_PASS_FD); | |
1747 | close(config_s[1]); | |
1748 | if (startup_pipe != -1) | |
1749 | close(startup_pipe); | |
1750 | ||
1751 | execv(rexec_argv[0], rexec_argv); | |
1752 | ||
1753 | /* Reexec has failed, fall back and continue */ | |
1754 | error("rexec of %s failed: %s", rexec_argv[0], strerror(errno)); | |
1755 | recv_rexec_state(REEXEC_CONFIG_PASS_FD, NULL); | |
1756 | log_init(__progname, options.log_level, | |
1757 | options.log_facility, log_stderr); | |
1758 | ||
1759 | /* Clean up fds */ | |
1760 | startup_pipe = REEXEC_STARTUP_PIPE_FD; | |
1761 | close(config_s[1]); | |
1762 | close(REEXEC_CONFIG_PASS_FD); | |
1763 | newsock = sock_out = sock_in = dup(STDIN_FILENO); | |
1764 | if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { | |
1765 | dup2(fd, STDIN_FILENO); | |
1766 | dup2(fd, STDOUT_FILENO); | |
1767 | if (fd > STDERR_FILENO) | |
1768 | close(fd); | |
1769 | } | |
1770 | debug("rexec cleanup in %d out %d newsock %d pipe %d sock %d", | |
1771 | sock_in, sock_out, newsock, startup_pipe, config_s[0]); | |
1772 | } | |
1773 | ||
3c0ef626 | 1774 | /* |
1775 | * Disable the key regeneration alarm. We will not regenerate the | |
1776 | * key since we are no longer in a position to give it to anyone. We | |
1777 | * will not restart on SIGHUP since it no longer makes sense. | |
1778 | */ | |
1779 | alarm(0); | |
1780 | signal(SIGALRM, SIG_DFL); | |
1781 | signal(SIGHUP, SIG_DFL); | |
1782 | signal(SIGTERM, SIG_DFL); | |
1783 | signal(SIGQUIT, SIG_DFL); | |
1784 | signal(SIGCHLD, SIG_DFL); | |
1785 | signal(SIGINT, SIG_DFL); | |
1786 | ||
3c0ef626 | 1787 | /* |
1788 | * Register our connection. This turns encryption off because we do | |
1789 | * not have a key. | |
1790 | */ | |
1791 | packet_set_connection(sock_in, sock_out); | |
2ce0bfe4 | 1792 | packet_set_server(); |
3c0ef626 | 1793 | |
2ce0bfe4 | 1794 | /* Set SO_KEEPALIVE if requested. */ |
1795 | if (options.tcp_keep_alive && packet_connection_is_on_socket() && | |
1796 | setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) < 0) | |
1797 | error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); | |
1798 | ||
1799 | if ((remote_port = get_remote_port()) < 0) { | |
1800 | debug("get_remote_port failed"); | |
1801 | cleanup_exit(255); | |
1802 | } | |
08822d99 | 1803 | |
76d45d2f | 1804 | /* set the HPN options for the child */ |
1805 | channel_set_hpn(options.hpn_disabled, options.hpn_buffer_size); | |
1806 | ||
08822d99 | 1807 | /* |
1808 | * We use get_canonical_hostname with usedns = 0 instead of | |
1809 | * get_remote_ipaddr here so IP options will be checked. | |
1810 | */ | |
30460aeb | 1811 | (void) get_canonical_hostname(0); |
1812 | /* | |
1813 | * The rest of the code depends on the fact that | |
1814 | * get_remote_ipaddr() caches the remote ip, even if | |
1815 | * the socket goes away. | |
1816 | */ | |
1817 | remote_ip = get_remote_ipaddr(); | |
3c0ef626 | 1818 | |
dfddba3d | 1819 | #ifdef SSH_AUDIT_EVENTS |
1820 | audit_connection_from(remote_ip, remote_port); | |
1821 | #endif | |
3c0ef626 | 1822 | #ifdef LIBWRAP |
e74dc197 | 1823 | allow_severity = options.log_facility|LOG_INFO; |
1824 | deny_severity = options.log_facility|LOG_WARNING; | |
3c0ef626 | 1825 | /* Check whether logins are denied from this host. */ |
7e82606e | 1826 | if (packet_connection_is_on_socket()) { |
3c0ef626 | 1827 | struct request_info req; |
1828 | ||
1829 | request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0); | |
1830 | fromhost(&req); | |
1831 | ||
1832 | if (!hosts_access(&req)) { | |
1833 | debug("Connection refused by tcp wrapper"); | |
1834 | refuse(&req); | |
1835 | /* NOTREACHED */ | |
1836 | fatal("libwrap refuse returns"); | |
1837 | } | |
1838 | } | |
1839 | #endif /* LIBWRAP */ | |
1840 | ||
1841 | /* Log the connection. */ | |
1842 | verbose("Connection from %.500s port %d", remote_ip, remote_port); | |
1843 | ||
fe4ad273 | 1844 | #ifdef USE_SECURITY_SESSION_API |
1845 | /* | |
1846 | * Create a new security session for use by the new user login if | |
1847 | * the current session is the root session or we are not launched | |
1848 | * by inetd (eg: debugging mode or server mode). We do not | |
1849 | * necessarily need to create a session if we are launched from | |
1850 | * inetd because Panther xinetd will create a session for us. | |
1851 | * | |
1852 | * The only case where this logic will fail is if there is an | |
1853 | * inetd running in a non-root session which is not creating | |
1854 | * new sessions for us. Then all the users will end up in the | |
1855 | * same session (bad). | |
1856 | * | |
1857 | * When the client exits, the session will be destroyed for us | |
1858 | * automatically. | |
1859 | * | |
1860 | * We must create the session before any credentials are stored | |
1861 | * (including AFS pags, which happens a few lines below). | |
1862 | */ | |
1863 | { | |
1864 | OSStatus err = 0; | |
1865 | SecuritySessionId sid = 0; | |
1866 | SessionAttributeBits sattrs = 0; | |
1867 | ||
1868 | err = SessionGetInfo(callerSecuritySession, &sid, &sattrs); | |
1869 | if (err) | |
1870 | error("SessionGetInfo() failed with error %.8X", | |
1871 | (unsigned) err); | |
1872 | else | |
473db5ab | 1873 | debug("Current Session ID is %.8X / Session Attributes are %.8X", |
fe4ad273 | 1874 | (unsigned) sid, (unsigned) sattrs); |
1875 | ||
1876 | if (inetd_flag && !(sattrs & sessionIsRoot)) | |
1877 | debug("Running in inetd mode in a non-root session... " | |
1878 | "assuming inetd created the session for us."); | |
1879 | else { | |
1880 | debug("Creating new security session..."); | |
1881 | err = SessionCreate(0, sessionHasTTY | sessionIsRemote); | |
1882 | if (err) | |
1883 | error("SessionCreate() failed with error %.8X", | |
1884 | (unsigned) err); | |
1885 | ||
1886 | err = SessionGetInfo(callerSecuritySession, &sid, | |
1887 | &sattrs); | |
1888 | if (err) | |
1889 | error("SessionGetInfo() failed with error %.8X", | |
1890 | (unsigned) err); | |
1891 | else | |
473db5ab | 1892 | debug("New Session ID is %.8X / Session Attributes are %.8X", |
fe4ad273 | 1893 | (unsigned) sid, (unsigned) sattrs); |
1894 | } | |
1895 | } | |
1896 | #endif | |
1897 | ||
3c0ef626 | 1898 | /* |
08822d99 | 1899 | * We don't want to listen forever unless the other side |
3c0ef626 | 1900 | * successfully authenticates itself. So we set up an alarm which is |
1901 | * cleared after successful authentication. A limit of zero | |
08822d99 | 1902 | * indicates no limit. Note that we don't set the alarm in debugging |
3c0ef626 | 1903 | * mode; it is just annoying to have the server exit just when you |
1904 | * are about to discover the bug. | |
1905 | */ | |
1906 | signal(SIGALRM, grace_alarm_handler); | |
1907 | if (!debug_flag) | |
1908 | alarm(options.login_grace_time); | |
1909 | ||
1910 | sshd_exchange_identification(sock_in, sock_out); | |
7cac2b65 | 1911 | #if defined(AFS_KRB5) |
3c0ef626 | 1912 | /* If machine has AFS, set process authentication group. */ |
1913 | if (k_hasafs()) { | |
1914 | k_setpag(); | |
1915 | k_unlog(); | |
1916 | } | |
62eb343a | 1917 | #endif /* AFS || AFS_KRB5 */ |
3c0ef626 | 1918 | |
e74dc197 | 1919 | /* In inetd mode, generate ephemeral key only for proto 1 connections */ |
1920 | if (!compat20 && inetd_flag && sensitive_data.server_key == NULL) | |
1921 | generate_ephemeral_server_key(); | |
1922 | ||
3c0ef626 | 1923 | packet_set_nonblocking(); |
1924 | ||
540d72c3 | 1925 | /* allocate authentication context */ |
30460aeb | 1926 | authctxt = xcalloc(1, sizeof(*authctxt)); |
540d72c3 | 1927 | |
8b32eddc | 1928 | authctxt->loginmsg = &loginmsg; |
1929 | ||
540d72c3 | 1930 | /* XXX global for cleanup, access from other modules */ |
1931 | the_authctxt = authctxt; | |
1932 | ||
dfddba3d | 1933 | /* prepare buffer to collect messages to display to user after login */ |
1934 | buffer_init(&loginmsg); | |
1935 | ||
510132b6 | 1936 | if (use_privsep) |
540d72c3 | 1937 | if (privsep_preauth(authctxt) == 1) |
510132b6 | 1938 | goto authenticated; |
1939 | ||
3c0ef626 | 1940 | /* perform the key exchange */ |
1941 | /* authenticate user and start session */ | |
1942 | if (compat20) { | |
1943 | do_ssh2_kex(); | |
540d72c3 | 1944 | do_authentication2(authctxt); |
3c0ef626 | 1945 | } else { |
1946 | do_ssh1_kex(); | |
540d72c3 | 1947 | do_authentication(authctxt); |
510132b6 | 1948 | } |
1949 | /* | |
1950 | * If we use privilege separation, the unprivileged child transfers | |
1951 | * the current keystate and exits | |
1952 | */ | |
1953 | if (use_privsep) { | |
1954 | mm_send_keystate(pmonitor); | |
1955 | exit(0); | |
3c0ef626 | 1956 | } |
510132b6 | 1957 | |
1958 | authenticated: | |
08822d99 | 1959 | /* |
1960 | * Cancel the alarm we set to limit the time taken for | |
1961 | * authentication. | |
1962 | */ | |
1963 | alarm(0); | |
1964 | signal(SIGALRM, SIG_DFL); | |
30460aeb | 1965 | authctxt->authenticated = 1; |
08822d99 | 1966 | if (startup_pipe != -1) { |
1967 | close(startup_pipe); | |
1968 | startup_pipe = -1; | |
1969 | } | |
1970 | ||
dfddba3d | 1971 | #ifdef SSH_AUDIT_EVENTS |
1972 | audit_event(SSH_AUTH_SUCCESS); | |
1973 | #endif | |
1974 | ||
e74dc197 | 1975 | #ifdef GSSAPI |
05ed7e1e | 1976 | if (options.gss_authentication && options.gss_deleg_creds) { |
e74dc197 | 1977 | temporarily_use_uid(authctxt->pw); |
1978 | ssh_gssapi_storecreds(); | |
1979 | restore_uid(); | |
1980 | } | |
1981 | #endif | |
1982 | #ifdef USE_PAM | |
1983 | if (options.use_pam) { | |
1984 | do_pam_setcred(1); | |
1985 | do_pam_session(); | |
1986 | } | |
1987 | #endif | |
1988 | ||
510132b6 | 1989 | /* |
1990 | * In privilege separation, we fork another child and prepare | |
1991 | * file descriptor passing. | |
1992 | */ | |
1993 | if (use_privsep) { | |
1994 | privsep_postauth(authctxt); | |
1995 | /* the monitor process [priv] will not return */ | |
1996 | if (!compat20) | |
1997 | destroy_sensitive_data(); | |
1998 | } | |
1999 | ||
5156b1a1 | 2000 | packet_set_timeout(options.client_alive_interval, |
2001 | options.client_alive_count_max); | |
2002 | ||
540d72c3 | 2003 | /* Start session. */ |
510132b6 | 2004 | do_authenticated(authctxt); |
2005 | ||
3c0ef626 | 2006 | /* The connection has been terminated. */ |
5156b1a1 | 2007 | packet_get_state(MODE_IN, NULL, NULL, NULL, &ibytes); |
2008 | packet_get_state(MODE_OUT, NULL, NULL, NULL, &obytes); | |
2009 | verbose("Transferred: sent %llu, received %llu bytes", obytes, ibytes); | |
2010 | ||
2011 | verbose("Closing connection to %.500s port %d", remote_ip, remote_port); | |
3c0ef626 | 2012 | |
2013 | #ifdef USE_PAM | |
7cac2b65 | 2014 | if (options.use_pam) |
2015 | finish_pam(); | |
3c0ef626 | 2016 | #endif /* USE_PAM */ |
2017 | ||
dfddba3d | 2018 | #ifdef SSH_AUDIT_EVENTS |
2019 | PRIVSEP(audit_event(SSH_CONNECTION_CLOSE)); | |
2020 | #endif | |
2021 | ||
3c0ef626 | 2022 | packet_close(); |
510132b6 | 2023 | |
2024 | if (use_privsep) | |
2025 | mm_terminate(); | |
2026 | ||
3c0ef626 | 2027 | exit(0); |
2028 | } | |
2029 | ||
510132b6 | 2030 | /* |
2031 | * Decrypt session_key_int using our private server key and private host key | |
2032 | * (key with larger modulus first). | |
2033 | */ | |
2034 | int | |
2035 | ssh1_session_key(BIGNUM *session_key_int) | |
2036 | { | |
2037 | int rsafail = 0; | |
2038 | ||
30460aeb | 2039 | if (BN_cmp(sensitive_data.server_key->rsa->n, |
2040 | sensitive_data.ssh1_host_key->rsa->n) > 0) { | |
510132b6 | 2041 | /* Server key has bigger modulus. */ |
2042 | if (BN_num_bits(sensitive_data.server_key->rsa->n) < | |
30460aeb | 2043 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + |
2044 | SSH_KEY_BITS_RESERVED) { | |
2045 | fatal("do_connection: %s: " | |
2046 | "server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d", | |
510132b6 | 2047 | get_remote_ipaddr(), |
2048 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
2049 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), | |
2050 | SSH_KEY_BITS_RESERVED); | |
2051 | } | |
2052 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
2053 | sensitive_data.server_key->rsa) <= 0) | |
2054 | rsafail++; | |
2055 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
2056 | sensitive_data.ssh1_host_key->rsa) <= 0) | |
2057 | rsafail++; | |
2058 | } else { | |
2059 | /* Host key has bigger modulus (or they are equal). */ | |
2060 | if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) < | |
30460aeb | 2061 | BN_num_bits(sensitive_data.server_key->rsa->n) + |
2062 | SSH_KEY_BITS_RESERVED) { | |
2063 | fatal("do_connection: %s: " | |
2064 | "host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d", | |
510132b6 | 2065 | get_remote_ipaddr(), |
2066 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), | |
2067 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
2068 | SSH_KEY_BITS_RESERVED); | |
2069 | } | |
2070 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
2071 | sensitive_data.ssh1_host_key->rsa) < 0) | |
2072 | rsafail++; | |
2073 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
2074 | sensitive_data.server_key->rsa) < 0) | |
2075 | rsafail++; | |
2076 | } | |
2077 | return (rsafail); | |
2078 | } | |
3c0ef626 | 2079 | /* |
2080 | * SSH1 key exchange | |
2081 | */ | |
2082 | static void | |
2083 | do_ssh1_kex(void) | |
2084 | { | |
2085 | int i, len; | |
3c0ef626 | 2086 | int rsafail = 0; |
2087 | BIGNUM *session_key_int; | |
2088 | u_char session_key[SSH_SESSION_KEY_LENGTH]; | |
2089 | u_char cookie[8]; | |
2090 | u_int cipher_type, auth_mask, protocol_flags; | |
3c0ef626 | 2091 | |
2092 | /* | |
2093 | * Generate check bytes that the client must send back in the user | |
2094 | * packet in order for it to be accepted; this is used to defy ip | |
2095 | * spoofing attacks. Note that this only works against somebody | |
2096 | * doing IP spoofing from a remote machine; any machine on the local | |
2097 | * network can still see outgoing packets and catch the random | |
2098 | * cookie. This only affects rhosts authentication, and this is one | |
2099 | * of the reasons why it is inherently insecure. | |
2100 | */ | |
5156b1a1 | 2101 | arc4random_buf(cookie, sizeof(cookie)); |
3c0ef626 | 2102 | |
2103 | /* | |
2104 | * Send our public key. We include in the packet 64 bits of random | |
2105 | * data that must be matched in the reply in order to prevent IP | |
2106 | * spoofing. | |
2107 | */ | |
2108 | packet_start(SSH_SMSG_PUBLIC_KEY); | |
2109 | for (i = 0; i < 8; i++) | |
2110 | packet_put_char(cookie[i]); | |
2111 | ||
2112 | /* Store our public server RSA key. */ | |
2113 | packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n)); | |
2114 | packet_put_bignum(sensitive_data.server_key->rsa->e); | |
2115 | packet_put_bignum(sensitive_data.server_key->rsa->n); | |
2116 | ||
2117 | /* Store our public host RSA key. */ | |
2118 | packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); | |
2119 | packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e); | |
2120 | packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n); | |
2121 | ||
2122 | /* Put protocol flags. */ | |
2123 | packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN); | |
2124 | ||
2125 | /* Declare which ciphers we support. */ | |
2126 | packet_put_int(cipher_mask_ssh1(0)); | |
2127 | ||
2128 | /* Declare supported authentication types. */ | |
2129 | auth_mask = 0; | |
3c0ef626 | 2130 | if (options.rhosts_rsa_authentication) |
2131 | auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA; | |
2132 | if (options.rsa_authentication) | |
2133 | auth_mask |= 1 << SSH_AUTH_RSA; | |
b59afbfe | 2134 | if (options.challenge_response_authentication == 1) |
2135 | auth_mask |= 1 << SSH_AUTH_TIS; | |
3c0ef626 | 2136 | if (options.password_authentication) |
2137 | auth_mask |= 1 << SSH_AUTH_PASSWORD; | |
2138 | packet_put_int(auth_mask); | |
2139 | ||
2140 | /* Send the packet and wait for it to be sent. */ | |
2141 | packet_send(); | |
2142 | packet_write_wait(); | |
2143 | ||
2144 | debug("Sent %d bit server key and %d bit host key.", | |
2145 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
2146 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); | |
2147 | ||
2148 | /* Read clients reply (cipher type and session key). */ | |
1e608e42 | 2149 | packet_read_expect(SSH_CMSG_SESSION_KEY); |
3c0ef626 | 2150 | |
2151 | /* Get cipher type and check whether we accept this. */ | |
2152 | cipher_type = packet_get_char(); | |
2153 | ||
2154 | if (!(cipher_mask_ssh1(0) & (1 << cipher_type))) | |
2155 | packet_disconnect("Warning: client selects unsupported cipher."); | |
2156 | ||
2157 | /* Get check bytes from the packet. These must match those we | |
2158 | sent earlier with the public key packet. */ | |
2159 | for (i = 0; i < 8; i++) | |
2160 | if (cookie[i] != packet_get_char()) | |
2161 | packet_disconnect("IP Spoofing check bytes do not match."); | |
2162 | ||
2163 | debug("Encryption type: %.200s", cipher_name(cipher_type)); | |
2164 | ||
2165 | /* Get the encrypted integer. */ | |
1e608e42 | 2166 | if ((session_key_int = BN_new()) == NULL) |
2167 | fatal("do_ssh1_kex: BN_new failed"); | |
2168 | packet_get_bignum(session_key_int); | |
3c0ef626 | 2169 | |
2170 | protocol_flags = packet_get_int(); | |
2171 | packet_set_protocol_flags(protocol_flags); | |
1e608e42 | 2172 | packet_check_eom(); |
3c0ef626 | 2173 | |
510132b6 | 2174 | /* Decrypt session_key_int using host/server keys */ |
2175 | rsafail = PRIVSEP(ssh1_session_key(session_key_int)); | |
2176 | ||
3c0ef626 | 2177 | /* |
2178 | * Extract session key from the decrypted integer. The key is in the | |
2179 | * least significant 256 bits of the integer; the first byte of the | |
2180 | * key is in the highest bits. | |
2181 | */ | |
2182 | if (!rsafail) { | |
240debe0 | 2183 | (void) BN_mask_bits(session_key_int, sizeof(session_key) * 8); |
3c0ef626 | 2184 | len = BN_num_bytes(session_key_int); |
2ce0bfe4 | 2185 | if (len < 0 || (u_int)len > sizeof(session_key)) { |
240debe0 | 2186 | error("do_ssh1_kex: bad session key len from %s: " |
3c0ef626 | 2187 | "session_key_int %d > sizeof(session_key) %lu", |
2188 | get_remote_ipaddr(), len, (u_long)sizeof(session_key)); | |
2189 | rsafail++; | |
2190 | } else { | |
2191 | memset(session_key, 0, sizeof(session_key)); | |
2192 | BN_bn2bin(session_key_int, | |
2193 | session_key + sizeof(session_key) - len); | |
2194 | ||
7e82606e | 2195 | derive_ssh1_session_id( |
3c0ef626 | 2196 | sensitive_data.ssh1_host_key->rsa->n, |
7e82606e | 2197 | sensitive_data.server_key->rsa->n, |
2198 | cookie, session_id); | |
3c0ef626 | 2199 | /* |
2200 | * Xor the first 16 bytes of the session key with the | |
2201 | * session id. | |
2202 | */ | |
2203 | for (i = 0; i < 16; i++) | |
2204 | session_key[i] ^= session_id[i]; | |
2205 | } | |
2206 | } | |
2207 | if (rsafail) { | |
2208 | int bytes = BN_num_bytes(session_key_int); | |
1e608e42 | 2209 | u_char *buf = xmalloc(bytes); |
3c0ef626 | 2210 | MD5_CTX md; |
2211 | ||
7cac2b65 | 2212 | logit("do_connection: generating a fake encryption key"); |
3c0ef626 | 2213 | BN_bn2bin(session_key_int, buf); |
2214 | MD5_Init(&md); | |
2215 | MD5_Update(&md, buf, bytes); | |
2216 | MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); | |
2217 | MD5_Final(session_key, &md); | |
2218 | MD5_Init(&md); | |
2219 | MD5_Update(&md, session_key, 16); | |
2220 | MD5_Update(&md, buf, bytes); | |
2221 | MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); | |
2222 | MD5_Final(session_key + 16, &md); | |
2223 | memset(buf, 0, bytes); | |
2224 | xfree(buf); | |
2225 | for (i = 0; i < 16; i++) | |
2226 | session_id[i] = session_key[i] ^ session_key[i + 16]; | |
2227 | } | |
510132b6 | 2228 | /* Destroy the private and public keys. No longer. */ |
3c0ef626 | 2229 | destroy_sensitive_data(); |
2230 | ||
510132b6 | 2231 | if (use_privsep) |
2232 | mm_ssh1_session_id(session_id); | |
2233 | ||
3c0ef626 | 2234 | /* Destroy the decrypted integer. It is no longer needed. */ |
2235 | BN_clear_free(session_key_int); | |
2236 | ||
2237 | /* Set the session key. From this on all communications will be encrypted. */ | |
2238 | packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type); | |
2239 | ||
2240 | /* Destroy our copy of the session key. It is no longer needed. */ | |
2241 | memset(session_key, 0, sizeof(session_key)); | |
2242 | ||
2243 | debug("Received session key; encryption turned on."); | |
2244 | ||
44a053a3 | 2245 | /* Send an acknowledgment packet. Note that this packet is sent encrypted. */ |
3c0ef626 | 2246 | packet_start(SSH_SMSG_SUCCESS); |
2247 | packet_send(); | |
2248 | packet_write_wait(); | |
2249 | } | |
2250 | ||
2251 | /* | |
2252 | * SSH2 key exchange: diffie-hellman-group1-sha1 | |
2253 | */ | |
2254 | static void | |
2255 | do_ssh2_kex(void) | |
2256 | { | |
2257 | Kex *kex; | |
2258 | ||
6df46d40 | 2259 | myflag++; |
2260 | debug ("MYFLAG IS %d", myflag); | |
3c0ef626 | 2261 | if (options.ciphers != NULL) { |
2262 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = | |
2263 | myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; | |
a7213e65 | 2264 | } else if (options.none_enabled == 1) { |
2265 | debug ("WARNING: None cipher enabled"); | |
2266 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = | |
2267 | myproposal[PROPOSAL_ENC_ALGS_STOC] = KEX_ENCRYPT_INCLUDE_NONE; | |
3c0ef626 | 2268 | } |
2269 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = | |
2270 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]); | |
2271 | myproposal[PROPOSAL_ENC_ALGS_STOC] = | |
2272 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); | |
2273 | ||
2274 | if (options.macs != NULL) { | |
2275 | myproposal[PROPOSAL_MAC_ALGS_CTOS] = | |
2276 | myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; | |
2277 | } | |
2ce0bfe4 | 2278 | if (options.compression == COMP_NONE) { |
44a053a3 | 2279 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = |
2280 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "none"; | |
2ce0bfe4 | 2281 | } else if (options.compression == COMP_DELAYED) { |
2282 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = | |
2283 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com"; | |
44a053a3 | 2284 | } |
30460aeb | 2285 | |
3c0ef626 | 2286 | myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = list_hostkey_types(); |
2287 | ||
5598e598 | 2288 | #ifdef GSSAPI |
fe4ad273 | 2289 | { |
5598e598 | 2290 | char *orig; |
2291 | char *gss = NULL; | |
2292 | char *newstr = NULL; | |
fe4ad273 | 2293 | orig = myproposal[PROPOSAL_KEX_ALGS]; |
2294 | ||
2295 | /* | |
2d7c038e | 2296 | * If we don't have a host key, then there's no point advertising |
2297 | * the other key exchange algorithms | |
fe4ad273 | 2298 | */ |
2299 | ||
2300 | if (strlen(myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS]) == 0) | |
2301 | orig = NULL; | |
2302 | ||
2303 | if (options.gss_keyex) | |
2304 | gss = ssh_gssapi_server_mechanisms(); | |
2305 | else | |
2306 | gss = NULL; | |
2307 | ||
f713db99 | 2308 | if (gss && orig) |
2309 | xasprintf(&newstr, "%s,%s", gss, orig); | |
2310 | else if (gss) | |
fe4ad273 | 2311 | newstr = gss; |
f713db99 | 2312 | else if (orig) |
fe4ad273 | 2313 | newstr = orig; |
f713db99 | 2314 | |
fe4ad273 | 2315 | /* |
2316 | * If we've got GSSAPI mechanisms, then we've got the 'null' host | |
2317 | * key alg, but we can't tell people about it unless its the only | |
2318 | * host key algorithm we support | |
2319 | */ | |
2320 | if (gss && (strlen(myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS])) == 0) | |
2321 | myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = "null"; | |
2322 | ||
5598e598 | 2323 | if (newstr) |
fe4ad273 | 2324 | myproposal[PROPOSAL_KEX_ALGS] = newstr; |
5598e598 | 2325 | else |
2326 | fatal("No supported key exchange algorithms"); | |
fe4ad273 | 2327 | } |
5598e598 | 2328 | #endif |
2329 | ||
f713db99 | 2330 | /* start key exchange */ |
2331 | kex = kex_setup(myproposal); | |
2332 | kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server; | |
7e82606e | 2333 | kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server; |
bfe49944 | 2334 | kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; |
f713db99 | 2335 | kex->kex[KEX_DH_GEX_SHA256] = kexgex_server; |
bfe49944 | 2336 | #ifdef GSSAPI |
f97edba6 | 2337 | if (options.gss_keyex) { |
2338 | kex->kex[KEX_GSS_GRP1_SHA1] = kexgss_server; | |
2339 | kex->kex[KEX_GSS_GRP14_SHA1] = kexgss_server; | |
2340 | kex->kex[KEX_GSS_GEX_SHA1] = kexgss_server; | |
2341 | } | |
bfe49944 | 2342 | #endif |
30460aeb | 2343 | kex->server = 1; |
2344 | kex->client_version_string=client_version_string; | |
2345 | kex->server_version_string=server_version_string; | |
3c0ef626 | 2346 | kex->load_host_key=&get_hostkey_by_type; |
510132b6 | 2347 | kex->host_key_index=&get_hostkey_index; |
3c0ef626 | 2348 | |
2349 | xxx_kex = kex; | |
2350 | ||
2351 | dispatch_run(DISPATCH_BLOCK, &kex->done, kex); | |
2352 | ||
2353 | session_id2 = kex->session_id; | |
2354 | session_id2_len = kex->session_id_len; | |
2355 | ||
2356 | #ifdef DEBUG_KEXDH | |
2357 | /* send 1st encrypted/maced/compressed message */ | |
2358 | packet_start(SSH2_MSG_IGNORE); | |
2359 | packet_put_cstring("markus"); | |
2360 | packet_send(); | |
2361 | packet_write_wait(); | |
2362 | #endif | |
2363 | debug("KEX done"); | |
2364 | } | |
540d72c3 | 2365 | |
2366 | /* server specific fatal cleanup */ | |
2367 | void | |
2368 | cleanup_exit(int i) | |
2369 | { | |
2370 | if (the_authctxt) | |
2371 | do_cleanup(the_authctxt); | |
dfddba3d | 2372 | #ifdef SSH_AUDIT_EVENTS |
2373 | /* done after do_cleanup so it can cancel the PAM auth 'thread' */ | |
2374 | if (!use_privsep || mm_is_monitor()) | |
2375 | audit_event(SSH_CONNECTION_ABANDON); | |
2376 | #endif | |
540d72c3 | 2377 | _exit(i); |
2378 | } |