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0b90ac93 | 1 | /* $OpenBSD: sshd.c,v 1.349 2007/02/21 11:00:05 dtucker 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" | |
57 | #include <sys/wait.h> | |
58 | ||
59 | #include <errno.h> | |
60 | #include <fcntl.h> | |
61 | #include <netdb.h> | |
62 | #ifdef HAVE_PATHS_H | |
63 | #include <paths.h> | |
64 | #endif | |
65 | #include <grp.h> | |
66 | #include <pwd.h> | |
67 | #include <signal.h> | |
68 | #include <stdarg.h> | |
69 | #include <stdio.h> | |
70 | #include <stdlib.h> | |
71 | #include <string.h> | |
72 | #include <unistd.h> | |
3c0ef626 | 73 | |
74 | #include <openssl/dh.h> | |
75 | #include <openssl/bn.h> | |
1e608e42 | 76 | #include <openssl/md5.h> |
510132b6 | 77 | #include <openssl/rand.h> |
78 | #ifdef HAVE_SECUREWARE | |
79 | #include <sys/security.h> | |
80 | #include <prot.h> | |
81 | #endif | |
3c0ef626 | 82 | |
30460aeb | 83 | #include "xmalloc.h" |
3c0ef626 | 84 | #include "ssh.h" |
85 | #include "ssh1.h" | |
86 | #include "ssh2.h" | |
3c0ef626 | 87 | #include "rsa.h" |
88 | #include "sshpty.h" | |
89 | #include "packet.h" | |
3c0ef626 | 90 | #include "log.h" |
30460aeb | 91 | #include "buffer.h" |
3c0ef626 | 92 | #include "servconf.h" |
93 | #include "uidswap.h" | |
94 | #include "compat.h" | |
3c0ef626 | 95 | #include "cipher.h" |
3c0ef626 | 96 | #include "key.h" |
30460aeb | 97 | #include "kex.h" |
3c0ef626 | 98 | #include "dh.h" |
99 | #include "myproposal.h" | |
100 | #include "authfile.h" | |
101 | #include "pathnames.h" | |
102 | #include "atomicio.h" | |
103 | #include "canohost.h" | |
30460aeb | 104 | #include "hostfile.h" |
3c0ef626 | 105 | #include "auth.h" |
106 | #include "misc.h" | |
7e82606e | 107 | #include "msg.h" |
3c0ef626 | 108 | #include "dispatch.h" |
109 | #include "channels.h" | |
510132b6 | 110 | #include "session.h" |
111 | #include "monitor_mm.h" | |
112 | #include "monitor.h" | |
30460aeb | 113 | #ifdef GSSAPI |
114 | #include "ssh-gss.h" | |
115 | #endif | |
510132b6 | 116 | #include "monitor_wrap.h" |
117 | #include "monitor_fdpass.h" | |
30460aeb | 118 | #include "version.h" |
3c0ef626 | 119 | |
fe4ad273 | 120 | #ifdef USE_SECURITY_SESSION_API |
121 | #include <Security/AuthSession.h> | |
5598e598 | 122 | #endif |
123 | ||
3c0ef626 | 124 | #ifdef LIBWRAP |
125 | #include <tcpd.h> | |
126 | #include <syslog.h> | |
127 | int allow_severity = LOG_INFO; | |
128 | int deny_severity = LOG_WARNING; | |
129 | #endif /* LIBWRAP */ | |
130 | ||
131 | #ifndef O_NOCTTY | |
132 | #define O_NOCTTY 0 | |
133 | #endif | |
134 | ||
7e82606e | 135 | /* Re-exec fds */ |
136 | #define REEXEC_DEVCRYPTO_RESERVED_FD (STDERR_FILENO + 1) | |
137 | #define REEXEC_STARTUP_PIPE_FD (STDERR_FILENO + 2) | |
138 | #define REEXEC_CONFIG_PASS_FD (STDERR_FILENO + 3) | |
139 | #define REEXEC_MIN_FREE_FD (STDERR_FILENO + 4) | |
140 | ||
3c0ef626 | 141 | extern char *__progname; |
3c0ef626 | 142 | |
143 | /* Server configuration options. */ | |
144 | ServerOptions options; | |
145 | ||
146 | /* Name of the server configuration file. */ | |
147 | char *config_file_name = _PATH_SERVER_CONFIG_FILE; | |
148 | ||
3c0ef626 | 149 | /* |
150 | * Debug mode flag. This can be set on the command line. If debug | |
151 | * mode is enabled, extra debugging output will be sent to the system | |
152 | * log, the daemon will not go to background, and will exit after processing | |
153 | * the first connection. | |
154 | */ | |
155 | int debug_flag = 0; | |
156 | ||
157 | /* Flag indicating that the daemon should only test the configuration and keys. */ | |
158 | int test_flag = 0; | |
159 | ||
160 | /* Flag indicating that the daemon is being started from inetd. */ | |
161 | int inetd_flag = 0; | |
162 | ||
163 | /* Flag indicating that sshd should not detach and become a daemon. */ | |
164 | int no_daemon_flag = 0; | |
165 | ||
166 | /* debug goes to stderr unless inetd_flag is set */ | |
167 | int log_stderr = 0; | |
168 | ||
169 | /* Saved arguments to main(). */ | |
170 | char **saved_argv; | |
171 | int saved_argc; | |
172 | ||
7e82606e | 173 | /* re-exec */ |
174 | int rexeced_flag = 0; | |
175 | int rexec_flag = 1; | |
176 | int rexec_argc = 0; | |
177 | char **rexec_argv; | |
178 | ||
3c0ef626 | 179 | /* |
180 | * The sockets that the server is listening; this is used in the SIGHUP | |
181 | * signal handler. | |
182 | */ | |
183 | #define MAX_LISTEN_SOCKS 16 | |
184 | int listen_socks[MAX_LISTEN_SOCKS]; | |
185 | int num_listen_socks = 0; | |
186 | ||
187 | /* | |
188 | * the client's version string, passed by sshd2 in compat mode. if != NULL, | |
189 | * sshd will skip the version-number exchange | |
190 | */ | |
191 | char *client_version_string = NULL; | |
192 | char *server_version_string = NULL; | |
193 | ||
194 | /* for rekeying XXX fixme */ | |
195 | Kex *xxx_kex; | |
196 | ||
197 | /* | |
198 | * Any really sensitive data in the application is contained in this | |
199 | * structure. The idea is that this structure could be locked into memory so | |
200 | * that the pages do not get written into swap. However, there are some | |
201 | * problems. The private key contains BIGNUMs, and we do not (in principle) | |
202 | * have access to the internals of them, and locking just the structure is | |
203 | * not very useful. Currently, memory locking is not implemented. | |
204 | */ | |
205 | struct { | |
206 | Key *server_key; /* ephemeral server key */ | |
207 | Key *ssh1_host_key; /* ssh1 host key */ | |
208 | Key **host_keys; /* all private host keys */ | |
209 | int have_ssh1_key; | |
210 | int have_ssh2_key; | |
211 | u_char ssh1_cookie[SSH_SESSION_KEY_LENGTH]; | |
212 | } sensitive_data; | |
213 | ||
214 | /* | |
215 | * Flag indicating whether the RSA server key needs to be regenerated. | |
216 | * Is set in the SIGALRM handler and cleared when the key is regenerated. | |
217 | */ | |
1e608e42 | 218 | static volatile sig_atomic_t key_do_regen = 0; |
3c0ef626 | 219 | |
220 | /* This is set to true when a signal is received. */ | |
1e608e42 | 221 | static volatile sig_atomic_t received_sighup = 0; |
222 | static volatile sig_atomic_t received_sigterm = 0; | |
3c0ef626 | 223 | |
224 | /* session identifier, used by RSA-auth */ | |
225 | u_char session_id[16]; | |
226 | ||
227 | /* same for ssh2 */ | |
228 | u_char *session_id2 = NULL; | |
7cac2b65 | 229 | u_int session_id2_len = 0; |
3c0ef626 | 230 | |
231 | /* record remote hostname or ip */ | |
232 | u_int utmp_len = MAXHOSTNAMELEN; | |
233 | ||
1e608e42 | 234 | /* options.max_startup sized array of fd ints */ |
235 | int *startup_pipes = NULL; | |
236 | int startup_pipe; /* in child */ | |
237 | ||
510132b6 | 238 | /* variables used for privilege separation */ |
30460aeb | 239 | int use_privsep = -1; |
540d72c3 | 240 | struct monitor *pmonitor = NULL; |
510132b6 | 241 | |
540d72c3 | 242 | /* global authentication context */ |
243 | Authctxt *the_authctxt = NULL; | |
244 | ||
30460aeb | 245 | /* sshd_config buffer */ |
246 | Buffer cfg; | |
247 | ||
7e82606e | 248 | /* message to be displayed after login */ |
249 | Buffer loginmsg; | |
250 | ||
30460aeb | 251 | /* Unprivileged user */ |
252 | struct passwd *privsep_pw = NULL; | |
253 | ||
3c0ef626 | 254 | /* Prototypes for various functions defined later in this file. */ |
255 | void destroy_sensitive_data(void); | |
510132b6 | 256 | void demote_sensitive_data(void); |
3c0ef626 | 257 | |
258 | static void do_ssh1_kex(void); | |
259 | static void do_ssh2_kex(void); | |
260 | ||
261 | /* | |
262 | * Close all listening sockets | |
263 | */ | |
264 | static void | |
265 | close_listen_socks(void) | |
266 | { | |
267 | int i; | |
276b07a3 | 268 | |
3c0ef626 | 269 | for (i = 0; i < num_listen_socks; i++) |
270 | close(listen_socks[i]); | |
271 | num_listen_socks = -1; | |
272 | } | |
273 | ||
1e608e42 | 274 | static void |
275 | close_startup_pipes(void) | |
276 | { | |
277 | int i; | |
276b07a3 | 278 | |
1e608e42 | 279 | if (startup_pipes) |
280 | for (i = 0; i < options.max_startups; i++) | |
281 | if (startup_pipes[i] != -1) | |
282 | close(startup_pipes[i]); | |
283 | } | |
284 | ||
3c0ef626 | 285 | /* |
286 | * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP; | |
287 | * the effect is to reread the configuration file (and to regenerate | |
288 | * the server key). | |
289 | */ | |
30460aeb | 290 | |
291 | /*ARGSUSED*/ | |
3c0ef626 | 292 | static void |
293 | sighup_handler(int sig) | |
294 | { | |
1e608e42 | 295 | int save_errno = errno; |
296 | ||
3c0ef626 | 297 | received_sighup = 1; |
298 | signal(SIGHUP, sighup_handler); | |
1e608e42 | 299 | errno = save_errno; |
3c0ef626 | 300 | } |
301 | ||
302 | /* | |
303 | * Called from the main program after receiving SIGHUP. | |
304 | * Restarts the server. | |
305 | */ | |
306 | static void | |
307 | sighup_restart(void) | |
308 | { | |
7cac2b65 | 309 | logit("Received SIGHUP; restarting."); |
3c0ef626 | 310 | close_listen_socks(); |
1e608e42 | 311 | close_startup_pipes(); |
0b90ac93 | 312 | alarm(0); /* alarm timer persists across exec */ |
3c0ef626 | 313 | execv(saved_argv[0], saved_argv); |
7cac2b65 | 314 | logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0], |
276b07a3 | 315 | strerror(errno)); |
3c0ef626 | 316 | exit(1); |
317 | } | |
318 | ||
319 | /* | |
320 | * Generic signal handler for terminating signals in the master daemon. | |
321 | */ | |
30460aeb | 322 | /*ARGSUSED*/ |
3c0ef626 | 323 | static void |
324 | sigterm_handler(int sig) | |
325 | { | |
326 | received_sigterm = sig; | |
327 | } | |
328 | ||
329 | /* | |
330 | * SIGCHLD handler. This is called whenever a child dies. This will then | |
331 | * reap any zombies left by exited children. | |
332 | */ | |
30460aeb | 333 | /*ARGSUSED*/ |
3c0ef626 | 334 | static void |
335 | main_sigchld_handler(int sig) | |
336 | { | |
337 | int save_errno = errno; | |
276b07a3 | 338 | pid_t pid; |
3c0ef626 | 339 | int status; |
340 | ||
510132b6 | 341 | while ((pid = waitpid(-1, &status, WNOHANG)) > 0 || |
342 | (pid < 0 && errno == EINTR)) | |
3c0ef626 | 343 | ; |
344 | ||
345 | signal(SIGCHLD, main_sigchld_handler); | |
346 | errno = save_errno; | |
347 | } | |
348 | ||
349 | /* | |
350 | * Signal handler for the alarm after the login grace period has expired. | |
351 | */ | |
30460aeb | 352 | /*ARGSUSED*/ |
3c0ef626 | 353 | static void |
354 | grace_alarm_handler(int sig) | |
355 | { | |
540d72c3 | 356 | if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0) |
357 | kill(pmonitor->m_pid, SIGALRM); | |
358 | ||
3c0ef626 | 359 | /* Log error and exit. */ |
30460aeb | 360 | sigdie("Timeout before authentication for %s", get_remote_ipaddr()); |
3c0ef626 | 361 | } |
362 | ||
363 | /* | |
364 | * Signal handler for the key regeneration alarm. Note that this | |
365 | * alarm only occurs in the daemon waiting for connections, and it does not | |
366 | * do anything with the private key or random state before forking. | |
367 | * Thus there should be no concurrency control/asynchronous execution | |
368 | * problems. | |
369 | */ | |
370 | static void | |
371 | generate_ephemeral_server_key(void) | |
372 | { | |
d03f4262 | 373 | u_int32_t rnd = 0; |
3c0ef626 | 374 | int i; |
375 | ||
376 | verbose("Generating %s%d bit RSA key.", | |
377 | sensitive_data.server_key ? "new " : "", options.server_key_bits); | |
378 | if (sensitive_data.server_key != NULL) | |
379 | key_free(sensitive_data.server_key); | |
380 | sensitive_data.server_key = key_generate(KEY_RSA1, | |
381 | options.server_key_bits); | |
382 | verbose("RSA key generation complete."); | |
383 | ||
384 | for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) { | |
385 | if (i % 4 == 0) | |
d03f4262 | 386 | rnd = arc4random(); |
387 | sensitive_data.ssh1_cookie[i] = rnd & 0xff; | |
388 | rnd >>= 8; | |
3c0ef626 | 389 | } |
390 | arc4random_stir(); | |
391 | } | |
392 | ||
30460aeb | 393 | /*ARGSUSED*/ |
3c0ef626 | 394 | static void |
395 | key_regeneration_alarm(int sig) | |
396 | { | |
397 | int save_errno = errno; | |
276b07a3 | 398 | |
3c0ef626 | 399 | signal(SIGALRM, SIG_DFL); |
400 | errno = save_errno; | |
401 | key_do_regen = 1; | |
402 | } | |
403 | ||
404 | static void | |
405 | sshd_exchange_identification(int sock_in, int sock_out) | |
406 | { | |
2ce0bfe4 | 407 | u_int i; |
408 | int mismatch; | |
3c0ef626 | 409 | int remote_major, remote_minor; |
410 | int major, minor; | |
411 | char *s; | |
412 | char buf[256]; /* Must not be larger than remote_version. */ | |
413 | char remote_version[256]; /* Must be at least as big as buf. */ | |
414 | ||
415 | if ((options.protocol & SSH_PROTO_1) && | |
416 | (options.protocol & SSH_PROTO_2)) { | |
417 | major = PROTOCOL_MAJOR_1; | |
418 | minor = 99; | |
419 | } else if (options.protocol & SSH_PROTO_2) { | |
420 | major = PROTOCOL_MAJOR_2; | |
421 | minor = PROTOCOL_MINOR_2; | |
422 | } else { | |
423 | major = PROTOCOL_MAJOR_1; | |
424 | minor = PROTOCOL_MINOR_1; | |
425 | } | |
473db5ab | 426 | snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", major, minor, SSH_RELEASE); |
3c0ef626 | 427 | server_version_string = xstrdup(buf); |
428 | ||
7cac2b65 | 429 | /* Send our protocol version identification. */ |
430 | if (atomicio(vwrite, sock_out, server_version_string, | |
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++) { | |
440 | if (atomicio(read, sock_in, &buf[i], 1) != 1) { | |
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); |
3c0ef626 | 477 | |
478 | compat_datafellows(remote_version); | |
479 | ||
d03f4262 | 480 | if (datafellows & SSH_BUG_PROBE) { |
7cac2b65 | 481 | logit("probed from %s with %s. Don't panic.", |
d03f4262 | 482 | get_remote_ipaddr(), client_version_string); |
540d72c3 | 483 | cleanup_exit(255); |
d03f4262 | 484 | } |
485 | ||
3c0ef626 | 486 | if (datafellows & SSH_BUG_SCANNER) { |
7cac2b65 | 487 | logit("scanned from %s with %s. Don't panic.", |
3c0ef626 | 488 | get_remote_ipaddr(), client_version_string); |
540d72c3 | 489 | cleanup_exit(255); |
3c0ef626 | 490 | } |
491 | ||
492 | mismatch = 0; | |
1e608e42 | 493 | switch (remote_major) { |
3c0ef626 | 494 | case 1: |
495 | if (remote_minor == 99) { | |
496 | if (options.protocol & SSH_PROTO_2) | |
497 | enable_compat20(); | |
498 | else | |
499 | mismatch = 1; | |
500 | break; | |
501 | } | |
502 | if (!(options.protocol & SSH_PROTO_1)) { | |
503 | mismatch = 1; | |
504 | break; | |
505 | } | |
506 | if (remote_minor < 3) { | |
507 | packet_disconnect("Your ssh version is too old and " | |
508 | "is no longer supported. Please install a newer version."); | |
509 | } else if (remote_minor == 3) { | |
510 | /* note that this disables agent-forwarding */ | |
511 | enable_compat13(); | |
512 | } | |
513 | break; | |
514 | case 2: | |
515 | if (options.protocol & SSH_PROTO_2) { | |
516 | enable_compat20(); | |
517 | break; | |
518 | } | |
519 | /* FALLTHROUGH */ | |
520 | default: | |
521 | mismatch = 1; | |
522 | break; | |
523 | } | |
524 | chop(server_version_string); | |
525 | debug("Local version string %.200s", server_version_string); | |
526 | ||
527 | if (mismatch) { | |
528 | s = "Protocol major versions differ.\n"; | |
7cac2b65 | 529 | (void) atomicio(vwrite, sock_out, s, strlen(s)); |
3c0ef626 | 530 | close(sock_in); |
531 | close(sock_out); | |
7cac2b65 | 532 | logit("Protocol major versions differ for %s: %.200s vs. %.200s", |
3c0ef626 | 533 | get_remote_ipaddr(), |
534 | server_version_string, client_version_string); | |
540d72c3 | 535 | cleanup_exit(255); |
3c0ef626 | 536 | } |
537 | } | |
538 | ||
3c0ef626 | 539 | /* Destroy the host and server keys. They will no longer be needed. */ |
540 | void | |
541 | destroy_sensitive_data(void) | |
542 | { | |
543 | int i; | |
544 | ||
545 | if (sensitive_data.server_key) { | |
546 | key_free(sensitive_data.server_key); | |
547 | sensitive_data.server_key = NULL; | |
548 | } | |
1e608e42 | 549 | for (i = 0; i < options.num_host_key_files; i++) { |
3c0ef626 | 550 | if (sensitive_data.host_keys[i]) { |
551 | key_free(sensitive_data.host_keys[i]); | |
552 | sensitive_data.host_keys[i] = NULL; | |
553 | } | |
554 | } | |
555 | sensitive_data.ssh1_host_key = NULL; | |
556 | memset(sensitive_data.ssh1_cookie, 0, SSH_SESSION_KEY_LENGTH); | |
557 | } | |
558 | ||
510132b6 | 559 | /* Demote private to public keys for network child */ |
560 | void | |
561 | demote_sensitive_data(void) | |
562 | { | |
563 | Key *tmp; | |
564 | int i; | |
565 | ||
566 | if (sensitive_data.server_key) { | |
567 | tmp = key_demote(sensitive_data.server_key); | |
568 | key_free(sensitive_data.server_key); | |
569 | sensitive_data.server_key = tmp; | |
570 | } | |
571 | ||
572 | for (i = 0; i < options.num_host_key_files; i++) { | |
573 | if (sensitive_data.host_keys[i]) { | |
574 | tmp = key_demote(sensitive_data.host_keys[i]); | |
575 | key_free(sensitive_data.host_keys[i]); | |
576 | sensitive_data.host_keys[i] = tmp; | |
577 | if (tmp->type == KEY_RSA1) | |
578 | sensitive_data.ssh1_host_key = tmp; | |
579 | } | |
580 | } | |
581 | ||
582 | /* We do not clear ssh1_host key and cookie. XXX - Okay Niels? */ | |
583 | } | |
584 | ||
585 | static void | |
586 | privsep_preauth_child(void) | |
587 | { | |
d03f4262 | 588 | u_int32_t rnd[256]; |
589 | gid_t gidset[1]; | |
276b07a3 | 590 | int i; |
510132b6 | 591 | |
592 | /* Enable challenge-response authentication for privilege separation */ | |
593 | privsep_challenge_enable(); | |
594 | ||
595 | for (i = 0; i < 256; i++) | |
d03f4262 | 596 | rnd[i] = arc4random(); |
597 | RAND_seed(rnd, sizeof(rnd)); | |
510132b6 | 598 | |
599 | /* Demote the private keys to public keys. */ | |
600 | demote_sensitive_data(); | |
601 | ||
d03f4262 | 602 | /* Change our root directory */ |
510132b6 | 603 | if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1) |
604 | fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR, | |
605 | strerror(errno)); | |
606 | if (chdir("/") == -1) | |
607 | fatal("chdir(\"/\"): %s", strerror(errno)); | |
608 | ||
609 | /* Drop our privileges */ | |
30460aeb | 610 | debug3("privsep user:group %u:%u", (u_int)privsep_pw->pw_uid, |
611 | (u_int)privsep_pw->pw_gid); | |
276b07a3 | 612 | #if 0 |
12a403af | 613 | /* XXX not ready, too heavy after chroot */ |
30460aeb | 614 | do_setusercontext(privsep_pw); |
276b07a3 | 615 | #else |
30460aeb | 616 | gidset[0] = privsep_pw->pw_gid; |
276b07a3 | 617 | if (setgroups(1, gidset) < 0) |
618 | fatal("setgroups: %.100s", strerror(errno)); | |
30460aeb | 619 | permanently_set_uid(privsep_pw); |
276b07a3 | 620 | #endif |
510132b6 | 621 | } |
622 | ||
540d72c3 | 623 | static int |
624 | privsep_preauth(Authctxt *authctxt) | |
510132b6 | 625 | { |
510132b6 | 626 | int status; |
627 | pid_t pid; | |
628 | ||
629 | /* Set up unprivileged child process to deal with network data */ | |
630 | pmonitor = monitor_init(); | |
631 | /* Store a pointer to the kex for later rekeying */ | |
632 | pmonitor->m_pkex = &xxx_kex; | |
633 | ||
634 | pid = fork(); | |
635 | if (pid == -1) { | |
636 | fatal("fork of unprivileged child failed"); | |
637 | } else if (pid != 0) { | |
44a053a3 | 638 | debug2("Network child is on pid %ld", (long)pid); |
510132b6 | 639 | |
640 | close(pmonitor->m_recvfd); | |
540d72c3 | 641 | pmonitor->m_pid = pid; |
642 | monitor_child_preauth(authctxt, pmonitor); | |
510132b6 | 643 | close(pmonitor->m_sendfd); |
644 | ||
645 | /* Sync memory */ | |
646 | monitor_sync(pmonitor); | |
647 | ||
648 | /* Wait for the child's exit status */ | |
649 | while (waitpid(pid, &status, 0) < 0) | |
650 | if (errno != EINTR) | |
651 | break; | |
540d72c3 | 652 | return (1); |
510132b6 | 653 | } else { |
654 | /* child */ | |
655 | ||
656 | close(pmonitor->m_sendfd); | |
657 | ||
658 | /* Demote the child */ | |
659 | if (getuid() == 0 || geteuid() == 0) | |
660 | privsep_preauth_child(); | |
661 | setproctitle("%s", "[net]"); | |
662 | } | |
540d72c3 | 663 | return (0); |
510132b6 | 664 | } |
665 | ||
666 | static void | |
667 | privsep_postauth(Authctxt *authctxt) | |
668 | { | |
d03f4262 | 669 | #ifdef DISABLE_FD_PASSING |
276b07a3 | 670 | if (1) { |
671 | #else | |
510132b6 | 672 | if (authctxt->pw->pw_uid == 0 || options.use_login) { |
276b07a3 | 673 | #endif |
510132b6 | 674 | /* File descriptor passing is broken or root login */ |
510132b6 | 675 | use_privsep = 0; |
08822d99 | 676 | goto skip; |
510132b6 | 677 | } |
678 | ||
679 | /* New socket pair */ | |
680 | monitor_reinit(pmonitor); | |
681 | ||
682 | pmonitor->m_pid = fork(); | |
683 | if (pmonitor->m_pid == -1) | |
684 | fatal("fork of unprivileged child failed"); | |
685 | else if (pmonitor->m_pid != 0) { | |
44a053a3 | 686 | debug2("User child is on pid %ld", (long)pmonitor->m_pid); |
510132b6 | 687 | close(pmonitor->m_recvfd); |
7e82606e | 688 | buffer_clear(&loginmsg); |
510132b6 | 689 | monitor_child_postauth(pmonitor); |
690 | ||
691 | /* NEVERREACHED */ | |
692 | exit(0); | |
693 | } | |
694 | ||
695 | close(pmonitor->m_sendfd); | |
696 | ||
697 | /* Demote the private keys to public keys. */ | |
698 | demote_sensitive_data(); | |
699 | ||
700 | /* Drop privileges */ | |
701 | do_setusercontext(authctxt->pw); | |
702 | ||
08822d99 | 703 | skip: |
510132b6 | 704 | /* It is safe now to apply the key state */ |
705 | monitor_apply_keystate(pmonitor); | |
2ce0bfe4 | 706 | |
707 | /* | |
708 | * Tell the packet layer that authentication was successful, since | |
709 | * this information is not part of the key state. | |
710 | */ | |
711 | packet_set_authenticated(); | |
510132b6 | 712 | } |
713 | ||
3c0ef626 | 714 | static char * |
715 | list_hostkey_types(void) | |
716 | { | |
1e608e42 | 717 | Buffer b; |
540d72c3 | 718 | const char *p; |
719 | char *ret; | |
3c0ef626 | 720 | int i; |
1e608e42 | 721 | |
722 | buffer_init(&b); | |
723 | for (i = 0; i < options.num_host_key_files; i++) { | |
3c0ef626 | 724 | Key *key = sensitive_data.host_keys[i]; |
725 | if (key == NULL) | |
726 | continue; | |
1e608e42 | 727 | switch (key->type) { |
3c0ef626 | 728 | case KEY_RSA: |
729 | case KEY_DSA: | |
1e608e42 | 730 | if (buffer_len(&b) > 0) |
731 | buffer_append(&b, ",", 1); | |
732 | p = key_ssh_name(key); | |
733 | buffer_append(&b, p, strlen(p)); | |
3c0ef626 | 734 | break; |
735 | } | |
736 | } | |
1e608e42 | 737 | buffer_append(&b, "\0", 1); |
540d72c3 | 738 | ret = xstrdup(buffer_ptr(&b)); |
1e608e42 | 739 | buffer_free(&b); |
540d72c3 | 740 | debug("list_hostkey_types: %s", ret); |
741 | return ret; | |
3c0ef626 | 742 | } |
743 | ||
510132b6 | 744 | Key * |
3c0ef626 | 745 | get_hostkey_by_type(int type) |
746 | { | |
747 | int i; | |
276b07a3 | 748 | |
1e608e42 | 749 | for (i = 0; i < options.num_host_key_files; i++) { |
3c0ef626 | 750 | Key *key = sensitive_data.host_keys[i]; |
751 | if (key != NULL && key->type == type) | |
752 | return key; | |
753 | } | |
754 | return NULL; | |
755 | } | |
756 | ||
510132b6 | 757 | Key * |
758 | get_hostkey_by_index(int ind) | |
759 | { | |
760 | if (ind < 0 || ind >= options.num_host_key_files) | |
761 | return (NULL); | |
762 | return (sensitive_data.host_keys[ind]); | |
763 | } | |
764 | ||
765 | int | |
766 | get_hostkey_index(Key *key) | |
767 | { | |
768 | int i; | |
276b07a3 | 769 | |
510132b6 | 770 | for (i = 0; i < options.num_host_key_files; i++) { |
771 | if (key == sensitive_data.host_keys[i]) | |
772 | return (i); | |
773 | } | |
774 | return (-1); | |
775 | } | |
776 | ||
3c0ef626 | 777 | /* |
778 | * returns 1 if connection should be dropped, 0 otherwise. | |
779 | * dropping starts at connection #max_startups_begin with a probability | |
780 | * of (max_startups_rate/100). the probability increases linearly until | |
781 | * all connections are dropped for startups > max_startups | |
782 | */ | |
783 | static int | |
784 | drop_connection(int startups) | |
785 | { | |
dfddba3d | 786 | int p, r; |
3c0ef626 | 787 | |
788 | if (startups < options.max_startups_begin) | |
789 | return 0; | |
790 | if (startups >= options.max_startups) | |
791 | return 1; | |
792 | if (options.max_startups_rate == 100) | |
793 | return 1; | |
794 | ||
795 | p = 100 - options.max_startups_rate; | |
796 | p *= startups - options.max_startups_begin; | |
dfddba3d | 797 | p /= options.max_startups - options.max_startups_begin; |
3c0ef626 | 798 | p += options.max_startups_rate; |
dfddba3d | 799 | r = arc4random() % 100; |
3c0ef626 | 800 | |
dfddba3d | 801 | debug("drop_connection: p %d, r %d", p, r); |
3c0ef626 | 802 | return (r < p) ? 1 : 0; |
803 | } | |
804 | ||
1e608e42 | 805 | static void |
806 | usage(void) | |
807 | { | |
12a403af | 808 | fprintf(stderr, "%s, %s\n", |
dfddba3d | 809 | SSH_RELEASE, SSLeay_version(SSLEAY_VERSION)); |
12a403af | 810 | fprintf(stderr, |
811 | "usage: sshd [-46Ddeiqt] [-b bits] [-f config_file] [-g login_grace_time]\n" | |
812 | " [-h host_key_file] [-k key_gen_time] [-o option] [-p port] [-u len]\n" | |
813 | ); | |
1e608e42 | 814 | exit(1); |
815 | } | |
3c0ef626 | 816 | |
7e82606e | 817 | static void |
818 | send_rexec_state(int fd, Buffer *conf) | |
819 | { | |
820 | Buffer m; | |
821 | ||
822 | debug3("%s: entering fd = %d config len %d", __func__, fd, | |
823 | buffer_len(conf)); | |
824 | ||
825 | /* | |
826 | * Protocol from reexec master to child: | |
827 | * string configuration | |
828 | * u_int ephemeral_key_follows | |
829 | * bignum e (only if ephemeral_key_follows == 1) | |
830 | * bignum n " | |
831 | * bignum d " | |
832 | * bignum iqmp " | |
833 | * bignum p " | |
834 | * bignum q " | |
08822d99 | 835 | * string rngseed (only if OpenSSL is not self-seeded) |
7e82606e | 836 | */ |
837 | buffer_init(&m); | |
838 | buffer_put_cstring(&m, buffer_ptr(conf)); | |
839 | ||
840 | if (sensitive_data.server_key != NULL && | |
841 | sensitive_data.server_key->type == KEY_RSA1) { | |
842 | buffer_put_int(&m, 1); | |
843 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->e); | |
844 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->n); | |
845 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->d); | |
846 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->iqmp); | |
847 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->p); | |
848 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->q); | |
849 | } else | |
850 | buffer_put_int(&m, 0); | |
851 | ||
08822d99 | 852 | #ifndef OPENSSL_PRNG_ONLY |
853 | rexec_send_rng_seed(&m); | |
854 | #endif | |
855 | ||
7e82606e | 856 | if (ssh_msg_send(fd, 0, &m) == -1) |
857 | fatal("%s: ssh_msg_send failed", __func__); | |
858 | ||
859 | buffer_free(&m); | |
860 | ||
861 | debug3("%s: done", __func__); | |
862 | } | |
863 | ||
864 | static void | |
865 | recv_rexec_state(int fd, Buffer *conf) | |
866 | { | |
867 | Buffer m; | |
868 | char *cp; | |
869 | u_int len; | |
870 | ||
871 | debug3("%s: entering fd = %d", __func__, fd); | |
872 | ||
873 | buffer_init(&m); | |
874 | ||
875 | if (ssh_msg_recv(fd, &m) == -1) | |
876 | fatal("%s: ssh_msg_recv failed", __func__); | |
877 | if (buffer_get_char(&m) != 0) | |
878 | fatal("%s: rexec version mismatch", __func__); | |
879 | ||
880 | cp = buffer_get_string(&m, &len); | |
881 | if (conf != NULL) | |
882 | buffer_append(conf, cp, len + 1); | |
883 | xfree(cp); | |
884 | ||
885 | if (buffer_get_int(&m)) { | |
886 | if (sensitive_data.server_key != NULL) | |
887 | key_free(sensitive_data.server_key); | |
888 | sensitive_data.server_key = key_new_private(KEY_RSA1); | |
889 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->e); | |
890 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->n); | |
891 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->d); | |
892 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->iqmp); | |
893 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->p); | |
894 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->q); | |
895 | rsa_generate_additional_parameters( | |
896 | sensitive_data.server_key->rsa); | |
897 | } | |
08822d99 | 898 | |
899 | #ifndef OPENSSL_PRNG_ONLY | |
900 | rexec_recv_rng_seed(&m); | |
901 | #endif | |
902 | ||
7e82606e | 903 | buffer_free(&m); |
904 | ||
905 | debug3("%s: done", __func__); | |
906 | } | |
907 | ||
30460aeb | 908 | /* Accept a connection from inetd */ |
909 | static void | |
910 | server_accept_inetd(int *sock_in, int *sock_out) | |
911 | { | |
912 | int fd; | |
913 | ||
914 | startup_pipe = -1; | |
915 | if (rexeced_flag) { | |
916 | close(REEXEC_CONFIG_PASS_FD); | |
917 | *sock_in = *sock_out = dup(STDIN_FILENO); | |
918 | if (!debug_flag) { | |
919 | startup_pipe = dup(REEXEC_STARTUP_PIPE_FD); | |
920 | close(REEXEC_STARTUP_PIPE_FD); | |
921 | } | |
922 | } else { | |
923 | *sock_in = dup(STDIN_FILENO); | |
924 | *sock_out = dup(STDOUT_FILENO); | |
925 | } | |
926 | /* | |
927 | * We intentionally do not close the descriptors 0, 1, and 2 | |
928 | * as our code for setting the descriptors won't work if | |
929 | * ttyfd happens to be one of those. | |
930 | */ | |
931 | if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { | |
932 | dup2(fd, STDIN_FILENO); | |
933 | dup2(fd, STDOUT_FILENO); | |
934 | if (fd > STDOUT_FILENO) | |
935 | close(fd); | |
936 | } | |
937 | debug("inetd sockets after dupping: %d, %d", *sock_in, *sock_out); | |
938 | } | |
939 | ||
940 | /* | |
941 | * Listen for TCP connections | |
942 | */ | |
943 | static void | |
944 | server_listen(void) | |
945 | { | |
946 | int ret, listen_sock, on = 1; | |
947 | struct addrinfo *ai; | |
948 | char ntop[NI_MAXHOST], strport[NI_MAXSERV]; | |
2d7c038e | 949 | int socksize; |
950 | int socksizelen = sizeof(int); | |
30460aeb | 951 | |
952 | for (ai = options.listen_addrs; ai; ai = ai->ai_next) { | |
953 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) | |
954 | continue; | |
955 | if (num_listen_socks >= MAX_LISTEN_SOCKS) | |
956 | fatal("Too many listen sockets. " | |
957 | "Enlarge MAX_LISTEN_SOCKS"); | |
958 | if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen, | |
959 | ntop, sizeof(ntop), strport, sizeof(strport), | |
960 | NI_NUMERICHOST|NI_NUMERICSERV)) != 0) { | |
961 | error("getnameinfo failed: %.100s", | |
962 | (ret != EAI_SYSTEM) ? gai_strerror(ret) : | |
963 | strerror(errno)); | |
964 | continue; | |
965 | } | |
966 | /* Create socket for listening. */ | |
967 | listen_sock = socket(ai->ai_family, ai->ai_socktype, | |
968 | ai->ai_protocol); | |
969 | if (listen_sock < 0) { | |
970 | /* kernel may not support ipv6 */ | |
971 | verbose("socket: %.100s", strerror(errno)); | |
972 | continue; | |
973 | } | |
974 | if (set_nonblock(listen_sock) == -1) { | |
975 | close(listen_sock); | |
976 | continue; | |
977 | } | |
978 | /* | |
979 | * Set socket options. | |
980 | * Allow local port reuse in TIME_WAIT. | |
981 | */ | |
982 | if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR, | |
983 | &on, sizeof(on)) == -1) | |
984 | error("setsockopt SO_REUSEADDR: %s", strerror(errno)); | |
985 | ||
986 | debug("Bind to port %s on %s.", strport, ntop); | |
2d7c038e | 987 | |
988 | getsockopt(listen_sock, SOL_SOCKET, SO_RCVBUF, | |
989 | &socksize, &socksizelen); | |
990 | debug("Server TCP RWIN socket size: %d", socksize); | |
991 | debug("HPN Buffer Size: %d", options.hpn_buffer_size); | |
30460aeb | 992 | |
993 | /* Bind the socket to the desired port. */ | |
994 | if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) { | |
995 | error("Bind to port %s on %s failed: %.200s.", | |
996 | strport, ntop, strerror(errno)); | |
997 | close(listen_sock); | |
998 | continue; | |
999 | } | |
1000 | listen_socks[num_listen_socks] = listen_sock; | |
1001 | num_listen_socks++; | |
1002 | ||
1003 | /* Start listening on the port. */ | |
1004 | if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0) | |
1005 | fatal("listen on [%s]:%s: %.100s", | |
1006 | ntop, strport, strerror(errno)); | |
1007 | logit("Server listening on %s port %s.", ntop, strport); | |
1008 | } | |
1009 | freeaddrinfo(options.listen_addrs); | |
1010 | ||
1011 | if (!num_listen_socks) | |
1012 | fatal("Cannot bind any address."); | |
1013 | } | |
1014 | ||
1015 | /* | |
1016 | * The main TCP accept loop. Note that, for the non-debug case, returns | |
1017 | * from this function are in a forked subprocess. | |
1018 | */ | |
1019 | static void | |
1020 | server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s) | |
1021 | { | |
1022 | fd_set *fdset; | |
1023 | int i, j, ret, maxfd; | |
1024 | int key_used = 0, startups = 0; | |
1025 | int startup_p[2] = { -1 , -1 }; | |
1026 | struct sockaddr_storage from; | |
1027 | socklen_t fromlen; | |
1028 | pid_t pid; | |
1029 | ||
1030 | /* setup fd set for accept */ | |
1031 | fdset = NULL; | |
1032 | maxfd = 0; | |
1033 | for (i = 0; i < num_listen_socks; i++) | |
1034 | if (listen_socks[i] > maxfd) | |
1035 | maxfd = listen_socks[i]; | |
1036 | /* pipes connected to unauthenticated childs */ | |
1037 | startup_pipes = xcalloc(options.max_startups, sizeof(int)); | |
1038 | for (i = 0; i < options.max_startups; i++) | |
1039 | startup_pipes[i] = -1; | |
1040 | ||
1041 | /* | |
1042 | * Stay listening for connections until the system crashes or | |
1043 | * the daemon is killed with a signal. | |
1044 | */ | |
1045 | for (;;) { | |
1046 | if (received_sighup) | |
1047 | sighup_restart(); | |
1048 | if (fdset != NULL) | |
1049 | xfree(fdset); | |
1050 | fdset = (fd_set *)xcalloc(howmany(maxfd + 1, NFDBITS), | |
1051 | sizeof(fd_mask)); | |
1052 | ||
1053 | for (i = 0; i < num_listen_socks; i++) | |
1054 | FD_SET(listen_socks[i], fdset); | |
1055 | for (i = 0; i < options.max_startups; i++) | |
1056 | if (startup_pipes[i] != -1) | |
1057 | FD_SET(startup_pipes[i], fdset); | |
1058 | ||
1059 | /* Wait in select until there is a connection. */ | |
1060 | ret = select(maxfd+1, fdset, NULL, NULL, NULL); | |
1061 | if (ret < 0 && errno != EINTR) | |
1062 | error("select: %.100s", strerror(errno)); | |
1063 | if (received_sigterm) { | |
1064 | logit("Received signal %d; terminating.", | |
1065 | (int) received_sigterm); | |
1066 | close_listen_socks(); | |
1067 | unlink(options.pid_file); | |
1068 | exit(255); | |
1069 | } | |
1070 | if (key_used && key_do_regen) { | |
1071 | generate_ephemeral_server_key(); | |
1072 | key_used = 0; | |
1073 | key_do_regen = 0; | |
1074 | } | |
1075 | if (ret < 0) | |
1076 | continue; | |
1077 | ||
1078 | for (i = 0; i < options.max_startups; i++) | |
1079 | if (startup_pipes[i] != -1 && | |
1080 | FD_ISSET(startup_pipes[i], fdset)) { | |
1081 | /* | |
1082 | * the read end of the pipe is ready | |
1083 | * if the child has closed the pipe | |
1084 | * after successful authentication | |
1085 | * or if the child has died | |
1086 | */ | |
1087 | close(startup_pipes[i]); | |
1088 | startup_pipes[i] = -1; | |
1089 | startups--; | |
1090 | } | |
1091 | for (i = 0; i < num_listen_socks; i++) { | |
1092 | if (!FD_ISSET(listen_socks[i], fdset)) | |
1093 | continue; | |
1094 | fromlen = sizeof(from); | |
1095 | *newsock = accept(listen_socks[i], | |
1096 | (struct sockaddr *)&from, &fromlen); | |
1097 | if (*newsock < 0) { | |
1098 | if (errno != EINTR && errno != EWOULDBLOCK) | |
1099 | error("accept: %.100s", strerror(errno)); | |
1100 | continue; | |
1101 | } | |
1102 | if (unset_nonblock(*newsock) == -1) { | |
1103 | close(*newsock); | |
1104 | continue; | |
1105 | } | |
1106 | if (drop_connection(startups) == 1) { | |
1107 | debug("drop connection #%d", startups); | |
1108 | close(*newsock); | |
1109 | continue; | |
1110 | } | |
1111 | if (pipe(startup_p) == -1) { | |
1112 | close(*newsock); | |
1113 | continue; | |
1114 | } | |
1115 | ||
1116 | if (rexec_flag && socketpair(AF_UNIX, | |
1117 | SOCK_STREAM, 0, config_s) == -1) { | |
1118 | error("reexec socketpair: %s", | |
1119 | strerror(errno)); | |
1120 | close(*newsock); | |
1121 | close(startup_p[0]); | |
1122 | close(startup_p[1]); | |
1123 | continue; | |
1124 | } | |
1125 | ||
1126 | for (j = 0; j < options.max_startups; j++) | |
1127 | if (startup_pipes[j] == -1) { | |
1128 | startup_pipes[j] = startup_p[0]; | |
1129 | if (maxfd < startup_p[0]) | |
1130 | maxfd = startup_p[0]; | |
1131 | startups++; | |
1132 | break; | |
1133 | } | |
1134 | ||
1135 | /* | |
1136 | * Got connection. Fork a child to handle it, unless | |
1137 | * we are in debugging mode. | |
1138 | */ | |
1139 | if (debug_flag) { | |
1140 | /* | |
1141 | * In debugging mode. Close the listening | |
1142 | * socket, and start processing the | |
1143 | * connection without forking. | |
1144 | */ | |
1145 | debug("Server will not fork when running in debugging mode."); | |
1146 | close_listen_socks(); | |
1147 | *sock_in = *newsock; | |
1148 | *sock_out = *newsock; | |
1149 | close(startup_p[0]); | |
1150 | close(startup_p[1]); | |
1151 | startup_pipe = -1; | |
1152 | pid = getpid(); | |
1153 | if (rexec_flag) { | |
1154 | send_rexec_state(config_s[0], | |
1155 | &cfg); | |
1156 | close(config_s[0]); | |
1157 | } | |
1158 | break; | |
1159 | } | |
1160 | ||
1161 | /* | |
1162 | * Normal production daemon. Fork, and have | |
1163 | * the child process the connection. The | |
1164 | * parent continues listening. | |
1165 | */ | |
1166 | platform_pre_fork(); | |
1167 | if ((pid = fork()) == 0) { | |
1168 | /* | |
1169 | * Child. Close the listening and | |
1170 | * max_startup sockets. Start using | |
1171 | * the accepted socket. Reinitialize | |
1172 | * logging (since our pid has changed). | |
1173 | * We break out of the loop to handle | |
1174 | * the connection. | |
1175 | */ | |
1176 | platform_post_fork_child(); | |
1177 | startup_pipe = startup_p[1]; | |
1178 | close_startup_pipes(); | |
1179 | close_listen_socks(); | |
1180 | *sock_in = *newsock; | |
1181 | *sock_out = *newsock; | |
1182 | log_init(__progname, | |
1183 | options.log_level, | |
1184 | options.log_facility, | |
1185 | log_stderr); | |
1186 | if (rexec_flag) | |
1187 | close(config_s[0]); | |
1188 | break; | |
1189 | } | |
1190 | ||
1191 | /* Parent. Stay in the loop. */ | |
1192 | platform_post_fork_parent(pid); | |
1193 | if (pid < 0) | |
1194 | error("fork: %.100s", strerror(errno)); | |
1195 | else | |
1196 | debug("Forked child %ld.", (long)pid); | |
1197 | ||
1198 | close(startup_p[1]); | |
1199 | ||
1200 | if (rexec_flag) { | |
1201 | send_rexec_state(config_s[0], &cfg); | |
1202 | close(config_s[0]); | |
1203 | close(config_s[1]); | |
1204 | } | |
1205 | ||
1206 | /* | |
1207 | * Mark that the key has been used (it | |
1208 | * was "given" to the child). | |
1209 | */ | |
1210 | if ((options.protocol & SSH_PROTO_1) && | |
1211 | key_used == 0) { | |
1212 | /* Schedule server key regeneration alarm. */ | |
1213 | signal(SIGALRM, key_regeneration_alarm); | |
1214 | alarm(options.key_regeneration_time); | |
1215 | key_used = 1; | |
1216 | } | |
1217 | ||
1218 | close(*newsock); | |
1219 | ||
1220 | /* | |
1221 | * Ensure that our random state differs | |
1222 | * from that of the child | |
1223 | */ | |
1224 | arc4random_stir(); | |
1225 | } | |
1226 | ||
1227 | /* child process check (or debug mode) */ | |
1228 | if (num_listen_socks < 0) | |
1229 | break; | |
1230 | } | |
1231 | } | |
1232 | ||
1233 | ||
3c0ef626 | 1234 | /* |
1235 | * Main program for the daemon. | |
1236 | */ | |
1237 | int | |
1238 | main(int ac, char **av) | |
1239 | { | |
1240 | extern char *optarg; | |
1241 | extern int optind; | |
30460aeb | 1242 | int opt, i, on = 1; |
7e82606e | 1243 | int sock_in = -1, sock_out = -1, newsock = -1; |
3c0ef626 | 1244 | const char *remote_ip; |
1245 | int remote_port; | |
540d72c3 | 1246 | char *line; |
30460aeb | 1247 | int config_s[2] = { -1 , -1 }; |
3c0ef626 | 1248 | Key *key; |
540d72c3 | 1249 | Authctxt *authctxt; |
3c0ef626 | 1250 | |
510132b6 | 1251 | #ifdef HAVE_SECUREWARE |
1252 | (void)set_auth_parameters(ac, av); | |
1253 | #endif | |
7cac2b65 | 1254 | __progname = ssh_get_progname(av[0]); |
3c0ef626 | 1255 | init_rng(); |
1256 | ||
bfe49944 | 1257 | /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */ |
3c0ef626 | 1258 | saved_argc = ac; |
7e82606e | 1259 | rexec_argc = ac; |
30460aeb | 1260 | saved_argv = xcalloc(ac + 1, sizeof(*saved_argv)); |
bfe49944 | 1261 | for (i = 0; i < ac; i++) |
1262 | saved_argv[i] = xstrdup(av[i]); | |
7cac2b65 | 1263 | saved_argv[i] = NULL; |
bfe49944 | 1264 | |
1265 | #ifndef HAVE_SETPROCTITLE | |
1266 | /* Prepare for later setproctitle emulation */ | |
1267 | compat_init_setproctitle(ac, av); | |
7cac2b65 | 1268 | av = saved_argv; |
bfe49944 | 1269 | #endif |
3c0ef626 | 1270 | |
12a403af | 1271 | if (geteuid() == 0 && setgroups(0, NULL) == -1) |
1272 | debug("setgroups(): %.200s", strerror(errno)); | |
1273 | ||
08822d99 | 1274 | /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ |
1275 | sanitise_stdfd(); | |
1276 | ||
3c0ef626 | 1277 | /* Initialize configuration options to their default values. */ |
1278 | initialize_server_options(&options); | |
1279 | ||
1280 | /* Parse command-line arguments. */ | |
7e82606e | 1281 | while ((opt = getopt(ac, av, "f:p:b:k:h:g:u:o:dDeiqrtQR46")) != -1) { |
3c0ef626 | 1282 | switch (opt) { |
1283 | case '4': | |
dfddba3d | 1284 | options.address_family = AF_INET; |
3c0ef626 | 1285 | break; |
1286 | case '6': | |
dfddba3d | 1287 | options.address_family = AF_INET6; |
3c0ef626 | 1288 | break; |
1289 | case 'f': | |
1290 | config_file_name = optarg; | |
1291 | break; | |
1292 | case 'd': | |
7cac2b65 | 1293 | if (debug_flag == 0) { |
3c0ef626 | 1294 | debug_flag = 1; |
1295 | options.log_level = SYSLOG_LEVEL_DEBUG1; | |
7cac2b65 | 1296 | } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) |
3c0ef626 | 1297 | options.log_level++; |
3c0ef626 | 1298 | break; |
1299 | case 'D': | |
1300 | no_daemon_flag = 1; | |
1301 | break; | |
1302 | case 'e': | |
1303 | log_stderr = 1; | |
1304 | break; | |
1305 | case 'i': | |
1306 | inetd_flag = 1; | |
1307 | break; | |
7e82606e | 1308 | case 'r': |
1309 | rexec_flag = 0; | |
1310 | break; | |
1311 | case 'R': | |
1312 | rexeced_flag = 1; | |
1313 | inetd_flag = 1; | |
1314 | break; | |
3c0ef626 | 1315 | case 'Q': |
1316 | /* ignored */ | |
1317 | break; | |
1318 | case 'q': | |
1319 | options.log_level = SYSLOG_LEVEL_QUIET; | |
1320 | break; | |
1321 | case 'b': | |
30460aeb | 1322 | options.server_key_bits = (int)strtonum(optarg, 256, |
1323 | 32768, NULL); | |
3c0ef626 | 1324 | break; |
1325 | case 'p': | |
1326 | options.ports_from_cmdline = 1; | |
1327 | if (options.num_ports >= MAX_PORTS) { | |
1328 | fprintf(stderr, "too many ports.\n"); | |
1329 | exit(1); | |
1330 | } | |
1331 | options.ports[options.num_ports++] = a2port(optarg); | |
1332 | if (options.ports[options.num_ports-1] == 0) { | |
1333 | fprintf(stderr, "Bad port number.\n"); | |
1334 | exit(1); | |
1335 | } | |
1336 | break; | |
1337 | case 'g': | |
1338 | if ((options.login_grace_time = convtime(optarg)) == -1) { | |
1339 | fprintf(stderr, "Invalid login grace time.\n"); | |
1340 | exit(1); | |
1341 | } | |
1342 | break; | |
1343 | case 'k': | |
1344 | if ((options.key_regeneration_time = convtime(optarg)) == -1) { | |
1345 | fprintf(stderr, "Invalid key regeneration interval.\n"); | |
1346 | exit(1); | |
1347 | } | |
1348 | break; | |
1349 | case 'h': | |
1350 | if (options.num_host_key_files >= MAX_HOSTKEYS) { | |
1351 | fprintf(stderr, "too many host keys.\n"); | |
1352 | exit(1); | |
1353 | } | |
1354 | options.host_key_files[options.num_host_key_files++] = optarg; | |
1355 | break; | |
3c0ef626 | 1356 | case 't': |
1357 | test_flag = 1; | |
1358 | break; | |
1359 | case 'u': | |
30460aeb | 1360 | utmp_len = (u_int)strtonum(optarg, 0, MAXHOSTNAMELEN+1, NULL); |
d03f4262 | 1361 | if (utmp_len > MAXHOSTNAMELEN) { |
1362 | fprintf(stderr, "Invalid utmp length.\n"); | |
1363 | exit(1); | |
1364 | } | |
3c0ef626 | 1365 | break; |
1e608e42 | 1366 | case 'o': |
540d72c3 | 1367 | line = xstrdup(optarg); |
1368 | if (process_server_config_line(&options, line, | |
30460aeb | 1369 | "command-line", 0, NULL, NULL, NULL, NULL) != 0) |
1e608e42 | 1370 | exit(1); |
540d72c3 | 1371 | xfree(line); |
1e608e42 | 1372 | break; |
3c0ef626 | 1373 | case '?': |
1374 | default: | |
1e608e42 | 1375 | usage(); |
1376 | break; | |
3c0ef626 | 1377 | } |
1378 | } | |
7e82606e | 1379 | if (rexeced_flag || inetd_flag) |
1380 | rexec_flag = 0; | |
1381 | if (rexec_flag && (av[0] == NULL || *av[0] != '/')) | |
1382 | fatal("sshd re-exec requires execution with an absolute path"); | |
1383 | if (rexeced_flag) | |
1384 | closefrom(REEXEC_MIN_FREE_FD); | |
1385 | else | |
1386 | closefrom(REEXEC_DEVCRYPTO_RESERVED_FD); | |
1387 | ||
3c0ef626 | 1388 | SSLeay_add_all_algorithms(); |
3c0ef626 | 1389 | |
1390 | /* | |
1391 | * Force logging to stderr until we have loaded the private host | |
1392 | * key (unless started from inetd) | |
1393 | */ | |
1394 | log_init(__progname, | |
1e608e42 | 1395 | options.log_level == SYSLOG_LEVEL_NOT_SET ? |
1396 | SYSLOG_LEVEL_INFO : options.log_level, | |
1397 | options.log_facility == SYSLOG_FACILITY_NOT_SET ? | |
1398 | SYSLOG_FACILITY_AUTH : options.log_facility, | |
bfe49944 | 1399 | log_stderr || !inetd_flag); |
3c0ef626 | 1400 | |
12a403af | 1401 | /* |
1402 | * Unset KRB5CCNAME, otherwise the user's session may inherit it from | |
1403 | * root's environment | |
2ce0bfe4 | 1404 | */ |
dfddba3d | 1405 | if (getenv("KRB5CCNAME") != NULL) |
1406 | unsetenv("KRB5CCNAME"); | |
1407 | ||
d03f4262 | 1408 | #ifdef _UNICOS |
7e82606e | 1409 | /* Cray can define user privs drop all privs now! |
3c0ef626 | 1410 | * Not needed on PRIV_SU systems! |
1411 | */ | |
1412 | drop_cray_privs(); | |
1413 | #endif | |
1414 | ||
7e82606e | 1415 | sensitive_data.server_key = NULL; |
1416 | sensitive_data.ssh1_host_key = NULL; | |
1417 | sensitive_data.have_ssh1_key = 0; | |
1418 | sensitive_data.have_ssh2_key = 0; | |
1419 | ||
1420 | /* Fetch our configuration */ | |
1421 | buffer_init(&cfg); | |
1422 | if (rexeced_flag) | |
1423 | recv_rexec_state(REEXEC_CONFIG_PASS_FD, &cfg); | |
1424 | else | |
1425 | load_server_config(config_file_name, &cfg); | |
1426 | ||
30460aeb | 1427 | parse_server_config(&options, rexeced_flag ? "rexec" : config_file_name, |
1428 | &cfg, NULL, NULL, NULL); | |
3c0ef626 | 1429 | |
08822d99 | 1430 | seed_rng(); |
1431 | ||
3c0ef626 | 1432 | /* Fill in default values for those options not explicitly set. */ |
1433 | fill_default_server_options(&options); | |
1434 | ||
dfddba3d | 1435 | /* set default channel AF */ |
1436 | channel_set_af(options.address_family); | |
1437 | ||
3c0ef626 | 1438 | /* Check that there are no remaining arguments. */ |
1439 | if (optind < ac) { | |
1440 | fprintf(stderr, "Extra argument %s.\n", av[optind]); | |
1441 | exit(1); | |
1442 | } | |
1443 | ||
dfddba3d | 1444 | debug("sshd version %.100s", SSH_RELEASE); |
3c0ef626 | 1445 | |
240debe0 | 1446 | /* Store privilege separation user for later use if required. */ |
1447 | if ((privsep_pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) { | |
1448 | if (use_privsep || options.kerberos_authentication) | |
1449 | fatal("Privilege separation user %s does not exist", | |
1450 | SSH_PRIVSEP_USER); | |
1451 | } else { | |
1452 | memset(privsep_pw->pw_passwd, 0, strlen(privsep_pw->pw_passwd)); | |
1453 | privsep_pw = pwcopy(privsep_pw); | |
1454 | xfree(privsep_pw->pw_passwd); | |
1455 | privsep_pw->pw_passwd = xstrdup("*"); | |
1456 | } | |
30460aeb | 1457 | endpwent(); |
1458 | ||
3c0ef626 | 1459 | /* load private host keys */ |
30460aeb | 1460 | sensitive_data.host_keys = xcalloc(options.num_host_key_files, |
d03f4262 | 1461 | sizeof(Key *)); |
1e608e42 | 1462 | for (i = 0; i < options.num_host_key_files; i++) |
3c0ef626 | 1463 | sensitive_data.host_keys[i] = NULL; |
3c0ef626 | 1464 | |
1e608e42 | 1465 | for (i = 0; i < options.num_host_key_files; i++) { |
3c0ef626 | 1466 | key = key_load_private(options.host_key_files[i], "", NULL); |
1467 | sensitive_data.host_keys[i] = key; | |
1468 | if (key == NULL) { | |
1469 | error("Could not load host key: %s", | |
1470 | options.host_key_files[i]); | |
1471 | sensitive_data.host_keys[i] = NULL; | |
1472 | continue; | |
1473 | } | |
1e608e42 | 1474 | switch (key->type) { |
3c0ef626 | 1475 | case KEY_RSA1: |
1476 | sensitive_data.ssh1_host_key = key; | |
1477 | sensitive_data.have_ssh1_key = 1; | |
1478 | break; | |
1479 | case KEY_RSA: | |
1480 | case KEY_DSA: | |
1481 | sensitive_data.have_ssh2_key = 1; | |
1482 | break; | |
1483 | } | |
1484 | debug("private host key: #%d type %d %s", i, key->type, | |
1485 | key_type(key)); | |
1486 | } | |
1487 | if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) { | |
7cac2b65 | 1488 | logit("Disabling protocol version 1. Could not load host key"); |
3c0ef626 | 1489 | options.protocol &= ~SSH_PROTO_1; |
1490 | } | |
5598e598 | 1491 | #ifndef GSSAPI |
1492 | /* The GSSAPI key exchange can run without a host key */ | |
3c0ef626 | 1493 | if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) { |
7cac2b65 | 1494 | logit("Disabling protocol version 2. Could not load host key"); |
3c0ef626 | 1495 | options.protocol &= ~SSH_PROTO_2; |
1496 | } | |
5598e598 | 1497 | #endif |
3c0ef626 | 1498 | if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) { |
7cac2b65 | 1499 | logit("sshd: no hostkeys available -- exiting."); |
3c0ef626 | 1500 | exit(1); |
1501 | } | |
1502 | ||
1503 | /* Check certain values for sanity. */ | |
1504 | if (options.protocol & SSH_PROTO_1) { | |
1505 | if (options.server_key_bits < 512 || | |
1506 | options.server_key_bits > 32768) { | |
1507 | fprintf(stderr, "Bad server key size.\n"); | |
1508 | exit(1); | |
1509 | } | |
1510 | /* | |
1511 | * Check that server and host key lengths differ sufficiently. This | |
1512 | * is necessary to make double encryption work with rsaref. Oh, I | |
1513 | * hate software patents. I dont know if this can go? Niels | |
1514 | */ | |
1515 | if (options.server_key_bits > | |
276b07a3 | 1516 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) - |
1517 | SSH_KEY_BITS_RESERVED && options.server_key_bits < | |
1518 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + | |
1519 | SSH_KEY_BITS_RESERVED) { | |
3c0ef626 | 1520 | options.server_key_bits = |
276b07a3 | 1521 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + |
1522 | SSH_KEY_BITS_RESERVED; | |
3c0ef626 | 1523 | debug("Forcing server key to %d bits to make it differ from host key.", |
1524 | options.server_key_bits); | |
1525 | } | |
1526 | } | |
1527 | ||
44a053a3 | 1528 | if (use_privsep) { |
44a053a3 | 1529 | struct stat st; |
1530 | ||
44a053a3 | 1531 | if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) || |
1532 | (S_ISDIR(st.st_mode) == 0)) | |
1533 | fatal("Missing privilege separation directory: %s", | |
1534 | _PATH_PRIVSEP_CHROOT_DIR); | |
d03f4262 | 1535 | |
1536 | #ifdef HAVE_CYGWIN | |
1537 | if (check_ntsec(_PATH_PRIVSEP_CHROOT_DIR) && | |
1538 | (st.st_uid != getuid () || | |
1539 | (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)) | |
1540 | #else | |
276b07a3 | 1541 | if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0) |
d03f4262 | 1542 | #endif |
bfe49944 | 1543 | fatal("%s must be owned by root and not group or " |
1544 | "world-writable.", _PATH_PRIVSEP_CHROOT_DIR); | |
44a053a3 | 1545 | } |
1546 | ||
3c0ef626 | 1547 | /* Configuration looks good, so exit if in test mode. */ |
1548 | if (test_flag) | |
1549 | exit(0); | |
1550 | ||
510132b6 | 1551 | /* |
1552 | * Clear out any supplemental groups we may have inherited. This | |
1553 | * prevents inadvertent creation of files with bad modes (in the | |
540d72c3 | 1554 | * portable version at least, it's certainly possible for PAM |
1555 | * to create a file, and we can't control the code in every | |
510132b6 | 1556 | * module which might be used). |
1557 | */ | |
1558 | if (setgroups(0, NULL) < 0) | |
1559 | debug("setgroups() failed: %.200s", strerror(errno)); | |
3c0ef626 | 1560 | |
7e82606e | 1561 | if (rexec_flag) { |
30460aeb | 1562 | rexec_argv = xcalloc(rexec_argc + 2, sizeof(char *)); |
7e82606e | 1563 | for (i = 0; i < rexec_argc; i++) { |
1564 | debug("rexec_argv[%d]='%s'", i, saved_argv[i]); | |
1565 | rexec_argv[i] = saved_argv[i]; | |
1566 | } | |
1567 | rexec_argv[rexec_argc] = "-R"; | |
1568 | rexec_argv[rexec_argc + 1] = NULL; | |
1569 | } | |
1570 | ||
3c0ef626 | 1571 | /* Initialize the log (it is reinitialized below in case we forked). */ |
dfddba3d | 1572 | if (debug_flag && (!inetd_flag || rexeced_flag)) |
3c0ef626 | 1573 | log_stderr = 1; |
1574 | log_init(__progname, options.log_level, options.log_facility, log_stderr); | |
1575 | ||
1576 | /* | |
1577 | * If not in debugging mode, and not started from inetd, disconnect | |
1578 | * from the controlling terminal, and fork. The original process | |
1579 | * exits. | |
1580 | */ | |
1581 | if (!(debug_flag || inetd_flag || no_daemon_flag)) { | |
1582 | #ifdef TIOCNOTTY | |
1583 | int fd; | |
1584 | #endif /* TIOCNOTTY */ | |
1585 | if (daemon(0, 0) < 0) | |
1586 | fatal("daemon() failed: %.200s", strerror(errno)); | |
1587 | ||
1588 | /* Disconnect from the controlling tty. */ | |
1589 | #ifdef TIOCNOTTY | |
1590 | fd = open(_PATH_TTY, O_RDWR | O_NOCTTY); | |
1591 | if (fd >= 0) { | |
1592 | (void) ioctl(fd, TIOCNOTTY, NULL); | |
1593 | close(fd); | |
1594 | } | |
1595 | #endif /* TIOCNOTTY */ | |
1596 | } | |
1597 | /* Reinitialize the log (because of the fork above). */ | |
1598 | log_init(__progname, options.log_level, options.log_facility, log_stderr); | |
1599 | ||
1600 | /* Initialize the random number generator. */ | |
1601 | arc4random_stir(); | |
1602 | ||
1603 | /* Chdir to the root directory so that the current disk can be | |
1604 | unmounted if desired. */ | |
1605 | chdir("/"); | |
1e608e42 | 1606 | |
3c0ef626 | 1607 | /* ignore SIGPIPE */ |
1608 | signal(SIGPIPE, SIG_IGN); | |
1609 | ||
30460aeb | 1610 | /* Get a connection, either from inetd or a listening TCP socket */ |
3c0ef626 | 1611 | if (inetd_flag) { |
30460aeb | 1612 | server_accept_inetd(&sock_in, &sock_out); |
7e82606e | 1613 | |
7e82606e | 1614 | if ((options.protocol & SSH_PROTO_1) && |
1615 | sensitive_data.server_key == NULL) | |
3c0ef626 | 1616 | generate_ephemeral_server_key(); |
1617 | } else { | |
30460aeb | 1618 | server_listen(); |
3c0ef626 | 1619 | |
1620 | if (options.protocol & SSH_PROTO_1) | |
1621 | generate_ephemeral_server_key(); | |
1622 | ||
3c0ef626 | 1623 | signal(SIGHUP, sighup_handler); |
30460aeb | 1624 | signal(SIGCHLD, main_sigchld_handler); |
3c0ef626 | 1625 | signal(SIGTERM, sigterm_handler); |
1626 | signal(SIGQUIT, sigterm_handler); | |
1627 | ||
30460aeb | 1628 | /* |
1629 | * Write out the pid file after the sigterm handler | |
1630 | * is setup and the listen sockets are bound | |
1631 | */ | |
3c0ef626 | 1632 | if (!debug_flag) { |
30460aeb | 1633 | FILE *f = fopen(options.pid_file, "w"); |
1634 | ||
7cac2b65 | 1635 | if (f == NULL) { |
1636 | error("Couldn't create pid file \"%s\": %s", | |
1637 | options.pid_file, strerror(errno)); | |
1638 | } else { | |
44a053a3 | 1639 | fprintf(f, "%ld\n", (long) getpid()); |
3c0ef626 | 1640 | fclose(f); |
1641 | } | |
1642 | } | |
1643 | ||
30460aeb | 1644 | /* Accept a connection and return in a forked child */ |
1645 | server_accept_loop(&sock_in, &sock_out, | |
1646 | &newsock, config_s); | |
3c0ef626 | 1647 | } |
1648 | ||
1649 | /* This is the child processing a new connection. */ | |
12a403af | 1650 | setproctitle("%s", "[accepted]"); |
3c0ef626 | 1651 | |
510132b6 | 1652 | /* |
1653 | * Create a new session and process group since the 4.4BSD | |
1654 | * setlogin() affects the entire process group. We don't | |
1655 | * want the child to be able to affect the parent. | |
1656 | */ | |
7cac2b65 | 1657 | #if !defined(SSHD_ACQUIRES_CTTY) |
bfe49944 | 1658 | /* |
7cac2b65 | 1659 | * If setsid is called, on some platforms sshd will later acquire a |
1660 | * controlling terminal which will result in "could not set | |
1661 | * controlling tty" errors. | |
bfe49944 | 1662 | */ |
276b07a3 | 1663 | if (!debug_flag && !inetd_flag && setsid() < 0) |
510132b6 | 1664 | error("setsid: %.100s", strerror(errno)); |
1665 | #endif | |
1666 | ||
7e82606e | 1667 | if (rexec_flag) { |
1668 | int fd; | |
1669 | ||
1670 | debug("rexec start in %d out %d newsock %d pipe %d sock %d", | |
1671 | sock_in, sock_out, newsock, startup_pipe, config_s[0]); | |
1672 | dup2(newsock, STDIN_FILENO); | |
1673 | dup2(STDIN_FILENO, STDOUT_FILENO); | |
1674 | if (startup_pipe == -1) | |
1675 | close(REEXEC_STARTUP_PIPE_FD); | |
1676 | else | |
1677 | dup2(startup_pipe, REEXEC_STARTUP_PIPE_FD); | |
1678 | ||
1679 | dup2(config_s[1], REEXEC_CONFIG_PASS_FD); | |
1680 | close(config_s[1]); | |
1681 | if (startup_pipe != -1) | |
1682 | close(startup_pipe); | |
1683 | ||
1684 | execv(rexec_argv[0], rexec_argv); | |
1685 | ||
1686 | /* Reexec has failed, fall back and continue */ | |
1687 | error("rexec of %s failed: %s", rexec_argv[0], strerror(errno)); | |
1688 | recv_rexec_state(REEXEC_CONFIG_PASS_FD, NULL); | |
1689 | log_init(__progname, options.log_level, | |
1690 | options.log_facility, log_stderr); | |
1691 | ||
1692 | /* Clean up fds */ | |
1693 | startup_pipe = REEXEC_STARTUP_PIPE_FD; | |
1694 | close(config_s[1]); | |
1695 | close(REEXEC_CONFIG_PASS_FD); | |
1696 | newsock = sock_out = sock_in = dup(STDIN_FILENO); | |
1697 | if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { | |
1698 | dup2(fd, STDIN_FILENO); | |
1699 | dup2(fd, STDOUT_FILENO); | |
1700 | if (fd > STDERR_FILENO) | |
1701 | close(fd); | |
1702 | } | |
1703 | debug("rexec cleanup in %d out %d newsock %d pipe %d sock %d", | |
1704 | sock_in, sock_out, newsock, startup_pipe, config_s[0]); | |
1705 | } | |
1706 | ||
3c0ef626 | 1707 | /* |
1708 | * Disable the key regeneration alarm. We will not regenerate the | |
1709 | * key since we are no longer in a position to give it to anyone. We | |
1710 | * will not restart on SIGHUP since it no longer makes sense. | |
1711 | */ | |
1712 | alarm(0); | |
1713 | signal(SIGALRM, SIG_DFL); | |
1714 | signal(SIGHUP, SIG_DFL); | |
1715 | signal(SIGTERM, SIG_DFL); | |
1716 | signal(SIGQUIT, SIG_DFL); | |
1717 | signal(SIGCHLD, SIG_DFL); | |
1718 | signal(SIGINT, SIG_DFL); | |
1719 | ||
3c0ef626 | 1720 | /* |
1721 | * Register our connection. This turns encryption off because we do | |
1722 | * not have a key. | |
1723 | */ | |
1724 | packet_set_connection(sock_in, sock_out); | |
2ce0bfe4 | 1725 | packet_set_server(); |
3c0ef626 | 1726 | |
2ce0bfe4 | 1727 | /* Set SO_KEEPALIVE if requested. */ |
1728 | if (options.tcp_keep_alive && packet_connection_is_on_socket() && | |
1729 | setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) < 0) | |
1730 | error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); | |
1731 | ||
1732 | if ((remote_port = get_remote_port()) < 0) { | |
1733 | debug("get_remote_port failed"); | |
1734 | cleanup_exit(255); | |
1735 | } | |
08822d99 | 1736 | |
1737 | /* | |
1738 | * We use get_canonical_hostname with usedns = 0 instead of | |
1739 | * get_remote_ipaddr here so IP options will be checked. | |
1740 | */ | |
30460aeb | 1741 | (void) get_canonical_hostname(0); |
1742 | /* | |
1743 | * The rest of the code depends on the fact that | |
1744 | * get_remote_ipaddr() caches the remote ip, even if | |
1745 | * the socket goes away. | |
1746 | */ | |
1747 | remote_ip = get_remote_ipaddr(); | |
3c0ef626 | 1748 | |
dfddba3d | 1749 | #ifdef SSH_AUDIT_EVENTS |
1750 | audit_connection_from(remote_ip, remote_port); | |
1751 | #endif | |
3c0ef626 | 1752 | #ifdef LIBWRAP |
1753 | /* Check whether logins are denied from this host. */ | |
7e82606e | 1754 | if (packet_connection_is_on_socket()) { |
3c0ef626 | 1755 | struct request_info req; |
1756 | ||
1757 | request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0); | |
1758 | fromhost(&req); | |
1759 | ||
1760 | if (!hosts_access(&req)) { | |
1761 | debug("Connection refused by tcp wrapper"); | |
1762 | refuse(&req); | |
1763 | /* NOTREACHED */ | |
1764 | fatal("libwrap refuse returns"); | |
1765 | } | |
1766 | } | |
1767 | #endif /* LIBWRAP */ | |
1768 | ||
1769 | /* Log the connection. */ | |
1770 | verbose("Connection from %.500s port %d", remote_ip, remote_port); | |
1771 | ||
fe4ad273 | 1772 | #ifdef USE_SECURITY_SESSION_API |
1773 | /* | |
1774 | * Create a new security session for use by the new user login if | |
1775 | * the current session is the root session or we are not launched | |
1776 | * by inetd (eg: debugging mode or server mode). We do not | |
1777 | * necessarily need to create a session if we are launched from | |
1778 | * inetd because Panther xinetd will create a session for us. | |
1779 | * | |
1780 | * The only case where this logic will fail is if there is an | |
1781 | * inetd running in a non-root session which is not creating | |
1782 | * new sessions for us. Then all the users will end up in the | |
1783 | * same session (bad). | |
1784 | * | |
1785 | * When the client exits, the session will be destroyed for us | |
1786 | * automatically. | |
1787 | * | |
1788 | * We must create the session before any credentials are stored | |
1789 | * (including AFS pags, which happens a few lines below). | |
1790 | */ | |
1791 | { | |
1792 | OSStatus err = 0; | |
1793 | SecuritySessionId sid = 0; | |
1794 | SessionAttributeBits sattrs = 0; | |
1795 | ||
1796 | err = SessionGetInfo(callerSecuritySession, &sid, &sattrs); | |
1797 | if (err) | |
1798 | error("SessionGetInfo() failed with error %.8X", | |
1799 | (unsigned) err); | |
1800 | else | |
473db5ab | 1801 | debug("Current Session ID is %.8X / Session Attributes are %.8X", |
fe4ad273 | 1802 | (unsigned) sid, (unsigned) sattrs); |
1803 | ||
1804 | if (inetd_flag && !(sattrs & sessionIsRoot)) | |
1805 | debug("Running in inetd mode in a non-root session... " | |
1806 | "assuming inetd created the session for us."); | |
1807 | else { | |
1808 | debug("Creating new security session..."); | |
1809 | err = SessionCreate(0, sessionHasTTY | sessionIsRemote); | |
1810 | if (err) | |
1811 | error("SessionCreate() failed with error %.8X", | |
1812 | (unsigned) err); | |
1813 | ||
1814 | err = SessionGetInfo(callerSecuritySession, &sid, | |
1815 | &sattrs); | |
1816 | if (err) | |
1817 | error("SessionGetInfo() failed with error %.8X", | |
1818 | (unsigned) err); | |
1819 | else | |
473db5ab | 1820 | debug("New Session ID is %.8X / Session Attributes are %.8X", |
fe4ad273 | 1821 | (unsigned) sid, (unsigned) sattrs); |
1822 | } | |
1823 | } | |
1824 | #endif | |
1825 | ||
3c0ef626 | 1826 | /* |
08822d99 | 1827 | * We don't want to listen forever unless the other side |
3c0ef626 | 1828 | * successfully authenticates itself. So we set up an alarm which is |
1829 | * cleared after successful authentication. A limit of zero | |
08822d99 | 1830 | * indicates no limit. Note that we don't set the alarm in debugging |
3c0ef626 | 1831 | * mode; it is just annoying to have the server exit just when you |
1832 | * are about to discover the bug. | |
1833 | */ | |
1834 | signal(SIGALRM, grace_alarm_handler); | |
1835 | if (!debug_flag) | |
1836 | alarm(options.login_grace_time); | |
1837 | ||
1838 | sshd_exchange_identification(sock_in, sock_out); | |
7cac2b65 | 1839 | #if defined(AFS_KRB5) |
3c0ef626 | 1840 | /* If machine has AFS, set process authentication group. */ |
1841 | if (k_hasafs()) { | |
1842 | k_setpag(); | |
1843 | k_unlog(); | |
1844 | } | |
62eb343a | 1845 | #endif /* AFS || AFS_KRB5 */ |
3c0ef626 | 1846 | |
1847 | packet_set_nonblocking(); | |
1848 | ||
540d72c3 | 1849 | /* allocate authentication context */ |
30460aeb | 1850 | authctxt = xcalloc(1, sizeof(*authctxt)); |
540d72c3 | 1851 | |
8b32eddc | 1852 | authctxt->loginmsg = &loginmsg; |
1853 | ||
540d72c3 | 1854 | /* XXX global for cleanup, access from other modules */ |
1855 | the_authctxt = authctxt; | |
1856 | ||
dfddba3d | 1857 | /* prepare buffer to collect messages to display to user after login */ |
1858 | buffer_init(&loginmsg); | |
1859 | ||
510132b6 | 1860 | if (use_privsep) |
540d72c3 | 1861 | if (privsep_preauth(authctxt) == 1) |
510132b6 | 1862 | goto authenticated; |
1863 | ||
3c0ef626 | 1864 | /* perform the key exchange */ |
1865 | /* authenticate user and start session */ | |
1866 | if (compat20) { | |
1867 | do_ssh2_kex(); | |
540d72c3 | 1868 | do_authentication2(authctxt); |
3c0ef626 | 1869 | } else { |
1870 | do_ssh1_kex(); | |
540d72c3 | 1871 | do_authentication(authctxt); |
510132b6 | 1872 | } |
1873 | /* | |
1874 | * If we use privilege separation, the unprivileged child transfers | |
1875 | * the current keystate and exits | |
1876 | */ | |
1877 | if (use_privsep) { | |
1878 | mm_send_keystate(pmonitor); | |
1879 | exit(0); | |
3c0ef626 | 1880 | } |
510132b6 | 1881 | |
1882 | authenticated: | |
08822d99 | 1883 | /* |
1884 | * Cancel the alarm we set to limit the time taken for | |
1885 | * authentication. | |
1886 | */ | |
1887 | alarm(0); | |
1888 | signal(SIGALRM, SIG_DFL); | |
30460aeb | 1889 | authctxt->authenticated = 1; |
08822d99 | 1890 | if (startup_pipe != -1) { |
1891 | close(startup_pipe); | |
1892 | startup_pipe = -1; | |
1893 | } | |
1894 | ||
dfddba3d | 1895 | #ifdef SSH_AUDIT_EVENTS |
1896 | audit_event(SSH_AUTH_SUCCESS); | |
1897 | #endif | |
1898 | ||
510132b6 | 1899 | /* |
1900 | * In privilege separation, we fork another child and prepare | |
1901 | * file descriptor passing. | |
1902 | */ | |
1903 | if (use_privsep) { | |
1904 | privsep_postauth(authctxt); | |
1905 | /* the monitor process [priv] will not return */ | |
1906 | if (!compat20) | |
1907 | destroy_sensitive_data(); | |
1908 | } | |
1909 | ||
540d72c3 | 1910 | /* Start session. */ |
510132b6 | 1911 | do_authenticated(authctxt); |
1912 | ||
3c0ef626 | 1913 | /* The connection has been terminated. */ |
1914 | verbose("Closing connection to %.100s", remote_ip); | |
1915 | ||
1916 | #ifdef USE_PAM | |
7cac2b65 | 1917 | if (options.use_pam) |
1918 | finish_pam(); | |
3c0ef626 | 1919 | #endif /* USE_PAM */ |
1920 | ||
dfddba3d | 1921 | #ifdef SSH_AUDIT_EVENTS |
1922 | PRIVSEP(audit_event(SSH_CONNECTION_CLOSE)); | |
1923 | #endif | |
1924 | ||
3c0ef626 | 1925 | packet_close(); |
510132b6 | 1926 | |
1927 | if (use_privsep) | |
1928 | mm_terminate(); | |
1929 | ||
3c0ef626 | 1930 | exit(0); |
1931 | } | |
1932 | ||
510132b6 | 1933 | /* |
1934 | * Decrypt session_key_int using our private server key and private host key | |
1935 | * (key with larger modulus first). | |
1936 | */ | |
1937 | int | |
1938 | ssh1_session_key(BIGNUM *session_key_int) | |
1939 | { | |
1940 | int rsafail = 0; | |
1941 | ||
30460aeb | 1942 | if (BN_cmp(sensitive_data.server_key->rsa->n, |
1943 | sensitive_data.ssh1_host_key->rsa->n) > 0) { | |
510132b6 | 1944 | /* Server key has bigger modulus. */ |
1945 | if (BN_num_bits(sensitive_data.server_key->rsa->n) < | |
30460aeb | 1946 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + |
1947 | SSH_KEY_BITS_RESERVED) { | |
1948 | fatal("do_connection: %s: " | |
1949 | "server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d", | |
510132b6 | 1950 | get_remote_ipaddr(), |
1951 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
1952 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), | |
1953 | SSH_KEY_BITS_RESERVED); | |
1954 | } | |
1955 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1956 | sensitive_data.server_key->rsa) <= 0) | |
1957 | rsafail++; | |
1958 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1959 | sensitive_data.ssh1_host_key->rsa) <= 0) | |
1960 | rsafail++; | |
1961 | } else { | |
1962 | /* Host key has bigger modulus (or they are equal). */ | |
1963 | if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) < | |
30460aeb | 1964 | BN_num_bits(sensitive_data.server_key->rsa->n) + |
1965 | SSH_KEY_BITS_RESERVED) { | |
1966 | fatal("do_connection: %s: " | |
1967 | "host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d", | |
510132b6 | 1968 | get_remote_ipaddr(), |
1969 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), | |
1970 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
1971 | SSH_KEY_BITS_RESERVED); | |
1972 | } | |
1973 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1974 | sensitive_data.ssh1_host_key->rsa) < 0) | |
1975 | rsafail++; | |
1976 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1977 | sensitive_data.server_key->rsa) < 0) | |
1978 | rsafail++; | |
1979 | } | |
1980 | return (rsafail); | |
1981 | } | |
3c0ef626 | 1982 | /* |
1983 | * SSH1 key exchange | |
1984 | */ | |
1985 | static void | |
1986 | do_ssh1_kex(void) | |
1987 | { | |
1988 | int i, len; | |
3c0ef626 | 1989 | int rsafail = 0; |
1990 | BIGNUM *session_key_int; | |
1991 | u_char session_key[SSH_SESSION_KEY_LENGTH]; | |
1992 | u_char cookie[8]; | |
1993 | u_int cipher_type, auth_mask, protocol_flags; | |
d03f4262 | 1994 | u_int32_t rnd = 0; |
3c0ef626 | 1995 | |
1996 | /* | |
1997 | * Generate check bytes that the client must send back in the user | |
1998 | * packet in order for it to be accepted; this is used to defy ip | |
1999 | * spoofing attacks. Note that this only works against somebody | |
2000 | * doing IP spoofing from a remote machine; any machine on the local | |
2001 | * network can still see outgoing packets and catch the random | |
2002 | * cookie. This only affects rhosts authentication, and this is one | |
2003 | * of the reasons why it is inherently insecure. | |
2004 | */ | |
2005 | for (i = 0; i < 8; i++) { | |
2006 | if (i % 4 == 0) | |
d03f4262 | 2007 | rnd = arc4random(); |
2008 | cookie[i] = rnd & 0xff; | |
2009 | rnd >>= 8; | |
3c0ef626 | 2010 | } |
2011 | ||
2012 | /* | |
2013 | * Send our public key. We include in the packet 64 bits of random | |
2014 | * data that must be matched in the reply in order to prevent IP | |
2015 | * spoofing. | |
2016 | */ | |
2017 | packet_start(SSH_SMSG_PUBLIC_KEY); | |
2018 | for (i = 0; i < 8; i++) | |
2019 | packet_put_char(cookie[i]); | |
2020 | ||
2021 | /* Store our public server RSA key. */ | |
2022 | packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n)); | |
2023 | packet_put_bignum(sensitive_data.server_key->rsa->e); | |
2024 | packet_put_bignum(sensitive_data.server_key->rsa->n); | |
2025 | ||
2026 | /* Store our public host RSA key. */ | |
2027 | packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); | |
2028 | packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e); | |
2029 | packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n); | |
2030 | ||
2031 | /* Put protocol flags. */ | |
2032 | packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN); | |
2033 | ||
2034 | /* Declare which ciphers we support. */ | |
2035 | packet_put_int(cipher_mask_ssh1(0)); | |
2036 | ||
2037 | /* Declare supported authentication types. */ | |
2038 | auth_mask = 0; | |
3c0ef626 | 2039 | if (options.rhosts_rsa_authentication) |
2040 | auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA; | |
2041 | if (options.rsa_authentication) | |
2042 | auth_mask |= 1 << SSH_AUTH_RSA; | |
b59afbfe | 2043 | if (options.challenge_response_authentication == 1) |
2044 | auth_mask |= 1 << SSH_AUTH_TIS; | |
3c0ef626 | 2045 | if (options.password_authentication) |
2046 | auth_mask |= 1 << SSH_AUTH_PASSWORD; | |
2047 | packet_put_int(auth_mask); | |
2048 | ||
2049 | /* Send the packet and wait for it to be sent. */ | |
2050 | packet_send(); | |
2051 | packet_write_wait(); | |
2052 | ||
2053 | debug("Sent %d bit server key and %d bit host key.", | |
2054 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
2055 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); | |
2056 | ||
2057 | /* Read clients reply (cipher type and session key). */ | |
1e608e42 | 2058 | packet_read_expect(SSH_CMSG_SESSION_KEY); |
3c0ef626 | 2059 | |
2060 | /* Get cipher type and check whether we accept this. */ | |
2061 | cipher_type = packet_get_char(); | |
2062 | ||
2063 | if (!(cipher_mask_ssh1(0) & (1 << cipher_type))) | |
2064 | packet_disconnect("Warning: client selects unsupported cipher."); | |
2065 | ||
2066 | /* Get check bytes from the packet. These must match those we | |
2067 | sent earlier with the public key packet. */ | |
2068 | for (i = 0; i < 8; i++) | |
2069 | if (cookie[i] != packet_get_char()) | |
2070 | packet_disconnect("IP Spoofing check bytes do not match."); | |
2071 | ||
2072 | debug("Encryption type: %.200s", cipher_name(cipher_type)); | |
2073 | ||
2074 | /* Get the encrypted integer. */ | |
1e608e42 | 2075 | if ((session_key_int = BN_new()) == NULL) |
2076 | fatal("do_ssh1_kex: BN_new failed"); | |
2077 | packet_get_bignum(session_key_int); | |
3c0ef626 | 2078 | |
2079 | protocol_flags = packet_get_int(); | |
2080 | packet_set_protocol_flags(protocol_flags); | |
1e608e42 | 2081 | packet_check_eom(); |
3c0ef626 | 2082 | |
510132b6 | 2083 | /* Decrypt session_key_int using host/server keys */ |
2084 | rsafail = PRIVSEP(ssh1_session_key(session_key_int)); | |
2085 | ||
3c0ef626 | 2086 | /* |
2087 | * Extract session key from the decrypted integer. The key is in the | |
2088 | * least significant 256 bits of the integer; the first byte of the | |
2089 | * key is in the highest bits. | |
2090 | */ | |
2091 | if (!rsafail) { | |
240debe0 | 2092 | (void) BN_mask_bits(session_key_int, sizeof(session_key) * 8); |
3c0ef626 | 2093 | len = BN_num_bytes(session_key_int); |
2ce0bfe4 | 2094 | if (len < 0 || (u_int)len > sizeof(session_key)) { |
240debe0 | 2095 | error("do_ssh1_kex: bad session key len from %s: " |
3c0ef626 | 2096 | "session_key_int %d > sizeof(session_key) %lu", |
2097 | get_remote_ipaddr(), len, (u_long)sizeof(session_key)); | |
2098 | rsafail++; | |
2099 | } else { | |
2100 | memset(session_key, 0, sizeof(session_key)); | |
2101 | BN_bn2bin(session_key_int, | |
2102 | session_key + sizeof(session_key) - len); | |
2103 | ||
7e82606e | 2104 | derive_ssh1_session_id( |
3c0ef626 | 2105 | sensitive_data.ssh1_host_key->rsa->n, |
7e82606e | 2106 | sensitive_data.server_key->rsa->n, |
2107 | cookie, session_id); | |
3c0ef626 | 2108 | /* |
2109 | * Xor the first 16 bytes of the session key with the | |
2110 | * session id. | |
2111 | */ | |
2112 | for (i = 0; i < 16; i++) | |
2113 | session_key[i] ^= session_id[i]; | |
2114 | } | |
2115 | } | |
2116 | if (rsafail) { | |
2117 | int bytes = BN_num_bytes(session_key_int); | |
1e608e42 | 2118 | u_char *buf = xmalloc(bytes); |
3c0ef626 | 2119 | MD5_CTX md; |
2120 | ||
7cac2b65 | 2121 | logit("do_connection: generating a fake encryption key"); |
3c0ef626 | 2122 | BN_bn2bin(session_key_int, buf); |
2123 | MD5_Init(&md); | |
2124 | MD5_Update(&md, buf, bytes); | |
2125 | MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); | |
2126 | MD5_Final(session_key, &md); | |
2127 | MD5_Init(&md); | |
2128 | MD5_Update(&md, session_key, 16); | |
2129 | MD5_Update(&md, buf, bytes); | |
2130 | MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); | |
2131 | MD5_Final(session_key + 16, &md); | |
2132 | memset(buf, 0, bytes); | |
2133 | xfree(buf); | |
2134 | for (i = 0; i < 16; i++) | |
2135 | session_id[i] = session_key[i] ^ session_key[i + 16]; | |
2136 | } | |
510132b6 | 2137 | /* Destroy the private and public keys. No longer. */ |
3c0ef626 | 2138 | destroy_sensitive_data(); |
2139 | ||
510132b6 | 2140 | if (use_privsep) |
2141 | mm_ssh1_session_id(session_id); | |
2142 | ||
3c0ef626 | 2143 | /* Destroy the decrypted integer. It is no longer needed. */ |
2144 | BN_clear_free(session_key_int); | |
2145 | ||
2146 | /* Set the session key. From this on all communications will be encrypted. */ | |
2147 | packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type); | |
2148 | ||
2149 | /* Destroy our copy of the session key. It is no longer needed. */ | |
2150 | memset(session_key, 0, sizeof(session_key)); | |
2151 | ||
2152 | debug("Received session key; encryption turned on."); | |
2153 | ||
44a053a3 | 2154 | /* Send an acknowledgment packet. Note that this packet is sent encrypted. */ |
3c0ef626 | 2155 | packet_start(SSH_SMSG_SUCCESS); |
2156 | packet_send(); | |
2157 | packet_write_wait(); | |
2158 | } | |
2159 | ||
2160 | /* | |
2161 | * SSH2 key exchange: diffie-hellman-group1-sha1 | |
2162 | */ | |
2163 | static void | |
2164 | do_ssh2_kex(void) | |
2165 | { | |
2166 | Kex *kex; | |
2167 | ||
2168 | if (options.ciphers != NULL) { | |
2169 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = | |
2170 | myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; | |
a7213e65 | 2171 | } else if (options.none_enabled == 1) { |
2172 | debug ("WARNING: None cipher enabled"); | |
2173 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = | |
2174 | myproposal[PROPOSAL_ENC_ALGS_STOC] = KEX_ENCRYPT_INCLUDE_NONE; | |
3c0ef626 | 2175 | } |
2176 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = | |
2177 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]); | |
2178 | myproposal[PROPOSAL_ENC_ALGS_STOC] = | |
2179 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); | |
2180 | ||
2181 | if (options.macs != NULL) { | |
2182 | myproposal[PROPOSAL_MAC_ALGS_CTOS] = | |
2183 | myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; | |
2184 | } | |
2ce0bfe4 | 2185 | if (options.compression == COMP_NONE) { |
44a053a3 | 2186 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = |
2187 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "none"; | |
2ce0bfe4 | 2188 | } else if (options.compression == COMP_DELAYED) { |
2189 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = | |
2190 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com"; | |
44a053a3 | 2191 | } |
30460aeb | 2192 | |
3c0ef626 | 2193 | myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = list_hostkey_types(); |
2194 | ||
5598e598 | 2195 | #ifdef GSSAPI |
fe4ad273 | 2196 | { |
5598e598 | 2197 | char *orig; |
2198 | char *gss = NULL; | |
2199 | char *newstr = NULL; | |
fe4ad273 | 2200 | orig = myproposal[PROPOSAL_KEX_ALGS]; |
2201 | ||
2202 | /* | |
2d7c038e | 2203 | * If we don't have a host key, then there's no point advertising |
2204 | * the other key exchange algorithms | |
fe4ad273 | 2205 | */ |
2206 | ||
2207 | if (strlen(myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS]) == 0) | |
2208 | orig = NULL; | |
2209 | ||
2210 | if (options.gss_keyex) | |
2211 | gss = ssh_gssapi_server_mechanisms(); | |
2212 | else | |
2213 | gss = NULL; | |
2214 | ||
f713db99 | 2215 | if (gss && orig) |
2216 | xasprintf(&newstr, "%s,%s", gss, orig); | |
2217 | else if (gss) | |
fe4ad273 | 2218 | newstr = gss; |
f713db99 | 2219 | else if (orig) |
fe4ad273 | 2220 | newstr = orig; |
f713db99 | 2221 | |
fe4ad273 | 2222 | /* |
2223 | * If we've got GSSAPI mechanisms, then we've got the 'null' host | |
2224 | * key alg, but we can't tell people about it unless its the only | |
2225 | * host key algorithm we support | |
2226 | */ | |
2227 | if (gss && (strlen(myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS])) == 0) | |
2228 | myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = "null"; | |
2229 | ||
5598e598 | 2230 | if (newstr) |
fe4ad273 | 2231 | myproposal[PROPOSAL_KEX_ALGS] = newstr; |
5598e598 | 2232 | else |
2233 | fatal("No supported key exchange algorithms"); | |
fe4ad273 | 2234 | } |
5598e598 | 2235 | #endif |
2236 | ||
2d7c038e | 2237 | /* start key exchange */ |
f713db99 | 2238 | /* start key exchange */ |
2239 | kex = kex_setup(myproposal); | |
2240 | kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server; | |
7e82606e | 2241 | kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server; |
bfe49944 | 2242 | kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; |
f713db99 | 2243 | kex->kex[KEX_DH_GEX_SHA256] = kexgex_server; |
bfe49944 | 2244 | #ifdef GSSAPI |
2245 | kex->kex[KEX_GSS_GRP1_SHA1] = kexgss_server; | |
f713db99 | 2246 | kex->kex[KEX_GSS_GRP14_SHA1] = kexgss_server; |
fe4ad273 | 2247 | kex->kex[KEX_GSS_GEX_SHA1] = kexgss_server; |
bfe49944 | 2248 | #endif |
30460aeb | 2249 | kex->server = 1; |
2250 | kex->client_version_string=client_version_string; | |
2251 | kex->server_version_string=server_version_string; | |
3c0ef626 | 2252 | kex->load_host_key=&get_hostkey_by_type; |
510132b6 | 2253 | kex->host_key_index=&get_hostkey_index; |
3c0ef626 | 2254 | |
2255 | xxx_kex = kex; | |
2256 | ||
2257 | dispatch_run(DISPATCH_BLOCK, &kex->done, kex); | |
2258 | ||
2259 | session_id2 = kex->session_id; | |
2260 | session_id2_len = kex->session_id_len; | |
2261 | ||
2262 | #ifdef DEBUG_KEXDH | |
2263 | /* send 1st encrypted/maced/compressed message */ | |
2264 | packet_start(SSH2_MSG_IGNORE); | |
2265 | packet_put_cstring("markus"); | |
2266 | packet_send(); | |
2267 | packet_write_wait(); | |
2268 | #endif | |
2269 | debug("KEX done"); | |
2270 | } | |
540d72c3 | 2271 | |
2272 | /* server specific fatal cleanup */ | |
2273 | void | |
2274 | cleanup_exit(int i) | |
2275 | { | |
2276 | if (the_authctxt) | |
2277 | do_cleanup(the_authctxt); | |
dfddba3d | 2278 | #ifdef SSH_AUDIT_EVENTS |
2279 | /* done after do_cleanup so it can cancel the PAM auth 'thread' */ | |
2280 | if (!use_privsep || mm_is_monitor()) | |
2281 | audit_event(SSH_CONNECTION_ABANDON); | |
2282 | #endif | |
540d72c3 | 2283 | _exit(i); |
2284 | } |