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91d9cdd3 | 1 | /* $OpenBSD: sshd.c,v 1.366 2009/01/22 10:02:34 djm Exp $ */ |
3c0ef626 | 2 | /* |
3 | * Author: Tatu Ylonen <ylo@cs.hut.fi> | |
4 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland | |
5 | * All rights reserved | |
6 | * This program is the ssh daemon. It listens for connections from clients, | |
7 | * and performs authentication, executes use commands or shell, and forwards | |
8 | * information to/from the application to the user client over an encrypted | |
9 | * connection. This can also handle forwarding of X11, TCP/IP, and | |
10 | * authentication agent connections. | |
11 | * | |
12 | * As far as I am concerned, the code I have written for this software | |
13 | * can be used freely for any purpose. Any derived versions of this | |
14 | * software must be clearly marked as such, and if the derived work is | |
15 | * incompatible with the protocol description in the RFC file, it must be | |
16 | * called by a name other than "ssh" or "Secure Shell". | |
17 | * | |
18 | * SSH2 implementation: | |
700318f3 | 19 | * Privilege Separation: |
3c0ef626 | 20 | * |
700318f3 | 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" | |
9108f8d9 | 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" | |
22616013 | 57 | #include "openbsd-compat/sys-queue.h" |
9108f8d9 | 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> | |
e9a17296 | 77 | #include <openssl/md5.h> |
700318f3 | 78 | #include <openssl/rand.h> |
47686178 | 79 | #include "openbsd-compat/openssl-compat.h" |
80 | ||
700318f3 | 81 | #ifdef HAVE_SECUREWARE |
82 | #include <sys/security.h> | |
83 | #include <prot.h> | |
84 | #endif | |
3c0ef626 | 85 | |
9108f8d9 | 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" |
9108f8d9 | 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" |
9108f8d9 | 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" | |
9108f8d9 | 107 | #include "hostfile.h" |
3c0ef626 | 108 | #include "auth.h" |
109 | #include "misc.h" | |
c9f39d2c | 110 | #include "msg.h" |
3c0ef626 | 111 | #include "dispatch.h" |
112 | #include "channels.h" | |
700318f3 | 113 | #include "session.h" |
114 | #include "monitor_mm.h" | |
115 | #include "monitor.h" | |
9108f8d9 | 116 | #ifdef GSSAPI |
117 | #include "ssh-gss.h" | |
118 | #endif | |
700318f3 | 119 | #include "monitor_wrap.h" |
9108f8d9 | 120 | #include "version.h" |
3c0ef626 | 121 | |
122 | #ifdef LIBWRAP | |
123 | #include <tcpd.h> | |
124 | #include <syslog.h> | |
47686178 | 125 | int allow_severity; |
126 | int deny_severity; | |
3c0ef626 | 127 | #endif /* LIBWRAP */ |
128 | ||
129 | #ifndef O_NOCTTY | |
130 | #define O_NOCTTY 0 | |
131 | #endif | |
132 | ||
c9f39d2c | 133 | /* Re-exec fds */ |
134 | #define REEXEC_DEVCRYPTO_RESERVED_FD (STDERR_FILENO + 1) | |
135 | #define REEXEC_STARTUP_PIPE_FD (STDERR_FILENO + 2) | |
136 | #define REEXEC_CONFIG_PASS_FD (STDERR_FILENO + 3) | |
137 | #define REEXEC_MIN_FREE_FD (STDERR_FILENO + 4) | |
138 | ||
3c0ef626 | 139 | extern char *__progname; |
3c0ef626 | 140 | |
141 | /* Server configuration options. */ | |
142 | ServerOptions options; | |
143 | ||
144 | /* Name of the server configuration file. */ | |
145 | char *config_file_name = _PATH_SERVER_CONFIG_FILE; | |
146 | ||
3c0ef626 | 147 | /* |
148 | * Debug mode flag. This can be set on the command line. If debug | |
149 | * mode is enabled, extra debugging output will be sent to the system | |
150 | * log, the daemon will not go to background, and will exit after processing | |
151 | * the first connection. | |
152 | */ | |
153 | int debug_flag = 0; | |
154 | ||
155 | /* Flag indicating that the daemon should only test the configuration and keys. */ | |
156 | int test_flag = 0; | |
157 | ||
158 | /* Flag indicating that the daemon is being started from inetd. */ | |
159 | int inetd_flag = 0; | |
160 | ||
161 | /* Flag indicating that sshd should not detach and become a daemon. */ | |
162 | int no_daemon_flag = 0; | |
163 | ||
164 | /* debug goes to stderr unless inetd_flag is set */ | |
165 | int log_stderr = 0; | |
166 | ||
167 | /* Saved arguments to main(). */ | |
168 | char **saved_argv; | |
169 | int saved_argc; | |
170 | ||
c9f39d2c | 171 | /* re-exec */ |
172 | int rexeced_flag = 0; | |
173 | int rexec_flag = 1; | |
174 | int rexec_argc = 0; | |
175 | char **rexec_argv; | |
176 | ||
3c0ef626 | 177 | /* |
178 | * The sockets that the server is listening; this is used in the SIGHUP | |
179 | * signal handler. | |
180 | */ | |
181 | #define MAX_LISTEN_SOCKS 16 | |
182 | int listen_socks[MAX_LISTEN_SOCKS]; | |
183 | int num_listen_socks = 0; | |
184 | ||
185 | /* | |
186 | * the client's version string, passed by sshd2 in compat mode. if != NULL, | |
187 | * sshd will skip the version-number exchange | |
188 | */ | |
189 | char *client_version_string = NULL; | |
190 | char *server_version_string = NULL; | |
191 | ||
192 | /* for rekeying XXX fixme */ | |
193 | Kex *xxx_kex; | |
194 | ||
195 | /* | |
196 | * Any really sensitive data in the application is contained in this | |
197 | * structure. The idea is that this structure could be locked into memory so | |
198 | * that the pages do not get written into swap. However, there are some | |
199 | * problems. The private key contains BIGNUMs, and we do not (in principle) | |
200 | * have access to the internals of them, and locking just the structure is | |
201 | * not very useful. Currently, memory locking is not implemented. | |
202 | */ | |
203 | struct { | |
204 | Key *server_key; /* ephemeral server key */ | |
205 | Key *ssh1_host_key; /* ssh1 host key */ | |
206 | Key **host_keys; /* all private host keys */ | |
207 | int have_ssh1_key; | |
208 | int have_ssh2_key; | |
209 | u_char ssh1_cookie[SSH_SESSION_KEY_LENGTH]; | |
210 | } sensitive_data; | |
211 | ||
212 | /* | |
213 | * Flag indicating whether the RSA server key needs to be regenerated. | |
214 | * Is set in the SIGALRM handler and cleared when the key is regenerated. | |
215 | */ | |
e9a17296 | 216 | static volatile sig_atomic_t key_do_regen = 0; |
3c0ef626 | 217 | |
218 | /* This is set to true when a signal is received. */ | |
e9a17296 | 219 | static volatile sig_atomic_t received_sighup = 0; |
220 | static volatile sig_atomic_t received_sigterm = 0; | |
3c0ef626 | 221 | |
222 | /* session identifier, used by RSA-auth */ | |
223 | u_char session_id[16]; | |
224 | ||
225 | /* same for ssh2 */ | |
226 | u_char *session_id2 = NULL; | |
0fff78ff | 227 | u_int session_id2_len = 0; |
3c0ef626 | 228 | |
229 | /* record remote hostname or ip */ | |
230 | u_int utmp_len = MAXHOSTNAMELEN; | |
231 | ||
e9a17296 | 232 | /* options.max_startup sized array of fd ints */ |
233 | int *startup_pipes = NULL; | |
234 | int startup_pipe; /* in child */ | |
235 | ||
700318f3 | 236 | /* variables used for privilege separation */ |
9108f8d9 | 237 | int use_privsep = -1; |
cdd66111 | 238 | struct monitor *pmonitor = NULL; |
700318f3 | 239 | |
cdd66111 | 240 | /* global authentication context */ |
241 | Authctxt *the_authctxt = NULL; | |
242 | ||
9108f8d9 | 243 | /* sshd_config buffer */ |
244 | Buffer cfg; | |
245 | ||
c9f39d2c | 246 | /* message to be displayed after login */ |
247 | Buffer loginmsg; | |
248 | ||
9108f8d9 | 249 | /* Unprivileged user */ |
250 | struct passwd *privsep_pw = NULL; | |
251 | ||
3c0ef626 | 252 | /* Prototypes for various functions defined later in this file. */ |
253 | void destroy_sensitive_data(void); | |
700318f3 | 254 | void demote_sensitive_data(void); |
3c0ef626 | 255 | |
256 | static void do_ssh1_kex(void); | |
257 | static void do_ssh2_kex(void); | |
258 | ||
259 | /* | |
260 | * Close all listening sockets | |
261 | */ | |
262 | static void | |
263 | close_listen_socks(void) | |
264 | { | |
265 | int i; | |
680cee3b | 266 | |
3c0ef626 | 267 | for (i = 0; i < num_listen_socks; i++) |
268 | close(listen_socks[i]); | |
269 | num_listen_socks = -1; | |
270 | } | |
271 | ||
e9a17296 | 272 | static void |
273 | close_startup_pipes(void) | |
274 | { | |
275 | int i; | |
680cee3b | 276 | |
e9a17296 | 277 | if (startup_pipes) |
278 | for (i = 0; i < options.max_startups; i++) | |
279 | if (startup_pipes[i] != -1) | |
280 | close(startup_pipes[i]); | |
281 | } | |
282 | ||
3c0ef626 | 283 | /* |
284 | * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP; | |
285 | * the effect is to reread the configuration file (and to regenerate | |
286 | * the server key). | |
287 | */ | |
9108f8d9 | 288 | |
289 | /*ARGSUSED*/ | |
3c0ef626 | 290 | static void |
291 | sighup_handler(int sig) | |
292 | { | |
e9a17296 | 293 | int save_errno = errno; |
294 | ||
3c0ef626 | 295 | received_sighup = 1; |
296 | signal(SIGHUP, sighup_handler); | |
e9a17296 | 297 | errno = save_errno; |
3c0ef626 | 298 | } |
299 | ||
300 | /* | |
301 | * Called from the main program after receiving SIGHUP. | |
302 | * Restarts the server. | |
303 | */ | |
304 | static void | |
305 | sighup_restart(void) | |
306 | { | |
0fff78ff | 307 | logit("Received SIGHUP; restarting."); |
3c0ef626 | 308 | close_listen_socks(); |
e9a17296 | 309 | close_startup_pipes(); |
799ae497 | 310 | alarm(0); /* alarm timer persists across exec */ |
3c0ef626 | 311 | execv(saved_argv[0], saved_argv); |
0fff78ff | 312 | logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0], |
680cee3b | 313 | strerror(errno)); |
3c0ef626 | 314 | exit(1); |
315 | } | |
316 | ||
317 | /* | |
318 | * Generic signal handler for terminating signals in the master daemon. | |
319 | */ | |
9108f8d9 | 320 | /*ARGSUSED*/ |
3c0ef626 | 321 | static void |
322 | sigterm_handler(int sig) | |
323 | { | |
324 | received_sigterm = sig; | |
325 | } | |
326 | ||
327 | /* | |
328 | * SIGCHLD handler. This is called whenever a child dies. This will then | |
329 | * reap any zombies left by exited children. | |
330 | */ | |
9108f8d9 | 331 | /*ARGSUSED*/ |
3c0ef626 | 332 | static void |
333 | main_sigchld_handler(int sig) | |
334 | { | |
335 | int save_errno = errno; | |
680cee3b | 336 | pid_t pid; |
3c0ef626 | 337 | int status; |
338 | ||
700318f3 | 339 | while ((pid = waitpid(-1, &status, WNOHANG)) > 0 || |
340 | (pid < 0 && errno == EINTR)) | |
3c0ef626 | 341 | ; |
342 | ||
343 | signal(SIGCHLD, main_sigchld_handler); | |
344 | errno = save_errno; | |
345 | } | |
346 | ||
347 | /* | |
348 | * Signal handler for the alarm after the login grace period has expired. | |
349 | */ | |
9108f8d9 | 350 | /*ARGSUSED*/ |
3c0ef626 | 351 | static void |
352 | grace_alarm_handler(int sig) | |
353 | { | |
cdd66111 | 354 | if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0) |
355 | kill(pmonitor->m_pid, SIGALRM); | |
356 | ||
3c0ef626 | 357 | /* Log error and exit. */ |
9108f8d9 | 358 | sigdie("Timeout before authentication for %s", get_remote_ipaddr()); |
3c0ef626 | 359 | } |
360 | ||
361 | /* | |
362 | * Signal handler for the key regeneration alarm. Note that this | |
363 | * alarm only occurs in the daemon waiting for connections, and it does not | |
364 | * do anything with the private key or random state before forking. | |
365 | * Thus there should be no concurrency control/asynchronous execution | |
366 | * problems. | |
367 | */ | |
368 | static void | |
369 | generate_ephemeral_server_key(void) | |
370 | { | |
3c0ef626 | 371 | verbose("Generating %s%d bit RSA key.", |
372 | sensitive_data.server_key ? "new " : "", options.server_key_bits); | |
373 | if (sensitive_data.server_key != NULL) | |
374 | key_free(sensitive_data.server_key); | |
375 | sensitive_data.server_key = key_generate(KEY_RSA1, | |
376 | options.server_key_bits); | |
377 | verbose("RSA key generation complete."); | |
378 | ||
22616013 | 379 | arc4random_buf(sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); |
3c0ef626 | 380 | arc4random_stir(); |
381 | } | |
382 | ||
9108f8d9 | 383 | /*ARGSUSED*/ |
3c0ef626 | 384 | static void |
385 | key_regeneration_alarm(int sig) | |
386 | { | |
387 | int save_errno = errno; | |
680cee3b | 388 | |
3c0ef626 | 389 | signal(SIGALRM, SIG_DFL); |
390 | errno = save_errno; | |
391 | key_do_regen = 1; | |
392 | } | |
393 | ||
394 | static void | |
395 | sshd_exchange_identification(int sock_in, int sock_out) | |
396 | { | |
665a873d | 397 | u_int i; |
398 | int mismatch; | |
3c0ef626 | 399 | int remote_major, remote_minor; |
400 | int major, minor; | |
22616013 | 401 | char *s, *newline = "\n"; |
3c0ef626 | 402 | char buf[256]; /* Must not be larger than remote_version. */ |
403 | char remote_version[256]; /* Must be at least as big as buf. */ | |
404 | ||
405 | if ((options.protocol & SSH_PROTO_1) && | |
406 | (options.protocol & SSH_PROTO_2)) { | |
407 | major = PROTOCOL_MAJOR_1; | |
408 | minor = 99; | |
409 | } else if (options.protocol & SSH_PROTO_2) { | |
410 | major = PROTOCOL_MAJOR_2; | |
411 | minor = PROTOCOL_MINOR_2; | |
22616013 | 412 | newline = "\r\n"; |
3c0ef626 | 413 | } else { |
414 | major = PROTOCOL_MAJOR_1; | |
415 | minor = PROTOCOL_MINOR_1; | |
416 | } | |
22616013 | 417 | snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s%s", major, minor, |
418 | SSH_VERSION, newline); | |
3c0ef626 | 419 | server_version_string = xstrdup(buf); |
420 | ||
0fff78ff | 421 | /* Send our protocol version identification. */ |
422 | if (atomicio(vwrite, sock_out, server_version_string, | |
423 | strlen(server_version_string)) | |
424 | != strlen(server_version_string)) { | |
425 | logit("Could not write ident string to %s", get_remote_ipaddr()); | |
cdd66111 | 426 | cleanup_exit(255); |
0fff78ff | 427 | } |
428 | ||
429 | /* Read other sides version identification. */ | |
430 | memset(buf, 0, sizeof(buf)); | |
431 | for (i = 0; i < sizeof(buf) - 1; i++) { | |
432 | if (atomicio(read, sock_in, &buf[i], 1) != 1) { | |
433 | logit("Did not receive identification string from %s", | |
434 | get_remote_ipaddr()); | |
cdd66111 | 435 | cleanup_exit(255); |
3c0ef626 | 436 | } |
0fff78ff | 437 | if (buf[i] == '\r') { |
438 | buf[i] = 0; | |
439 | /* Kludge for F-Secure Macintosh < 1.0.2 */ | |
440 | if (i == 12 && | |
441 | strncmp(buf, "SSH-1.5-W1.0", 12) == 0) | |
3c0ef626 | 442 | break; |
0fff78ff | 443 | continue; |
444 | } | |
445 | if (buf[i] == '\n') { | |
446 | buf[i] = 0; | |
447 | break; | |
3c0ef626 | 448 | } |
3c0ef626 | 449 | } |
0fff78ff | 450 | buf[sizeof(buf) - 1] = 0; |
451 | client_version_string = xstrdup(buf); | |
3c0ef626 | 452 | |
453 | /* | |
454 | * Check that the versions match. In future this might accept | |
455 | * several versions and set appropriate flags to handle them. | |
456 | */ | |
457 | if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n", | |
458 | &remote_major, &remote_minor, remote_version) != 3) { | |
459 | s = "Protocol mismatch.\n"; | |
0fff78ff | 460 | (void) atomicio(vwrite, sock_out, s, strlen(s)); |
3c0ef626 | 461 | close(sock_in); |
462 | close(sock_out); | |
0fff78ff | 463 | logit("Bad protocol version identification '%.100s' from %s", |
3c0ef626 | 464 | client_version_string, get_remote_ipaddr()); |
cdd66111 | 465 | cleanup_exit(255); |
3c0ef626 | 466 | } |
467 | debug("Client protocol version %d.%d; client software version %.100s", | |
e9a17296 | 468 | remote_major, remote_minor, remote_version); |
3c0ef626 | 469 | |
470 | compat_datafellows(remote_version); | |
471 | ||
41b2f314 | 472 | if (datafellows & SSH_BUG_PROBE) { |
0fff78ff | 473 | logit("probed from %s with %s. Don't panic.", |
41b2f314 | 474 | get_remote_ipaddr(), client_version_string); |
cdd66111 | 475 | cleanup_exit(255); |
41b2f314 | 476 | } |
477 | ||
3c0ef626 | 478 | if (datafellows & SSH_BUG_SCANNER) { |
0fff78ff | 479 | logit("scanned from %s with %s. Don't panic.", |
3c0ef626 | 480 | get_remote_ipaddr(), client_version_string); |
cdd66111 | 481 | cleanup_exit(255); |
3c0ef626 | 482 | } |
483 | ||
484 | mismatch = 0; | |
e9a17296 | 485 | switch (remote_major) { |
3c0ef626 | 486 | case 1: |
487 | if (remote_minor == 99) { | |
488 | if (options.protocol & SSH_PROTO_2) | |
489 | enable_compat20(); | |
490 | else | |
491 | mismatch = 1; | |
492 | break; | |
493 | } | |
494 | if (!(options.protocol & SSH_PROTO_1)) { | |
495 | mismatch = 1; | |
496 | break; | |
497 | } | |
498 | if (remote_minor < 3) { | |
499 | packet_disconnect("Your ssh version is too old and " | |
500 | "is no longer supported. Please install a newer version."); | |
501 | } else if (remote_minor == 3) { | |
502 | /* note that this disables agent-forwarding */ | |
503 | enable_compat13(); | |
504 | } | |
505 | break; | |
506 | case 2: | |
507 | if (options.protocol & SSH_PROTO_2) { | |
508 | enable_compat20(); | |
509 | break; | |
510 | } | |
511 | /* FALLTHROUGH */ | |
512 | default: | |
513 | mismatch = 1; | |
514 | break; | |
515 | } | |
516 | chop(server_version_string); | |
517 | debug("Local version string %.200s", server_version_string); | |
518 | ||
519 | if (mismatch) { | |
520 | s = "Protocol major versions differ.\n"; | |
0fff78ff | 521 | (void) atomicio(vwrite, sock_out, s, strlen(s)); |
3c0ef626 | 522 | close(sock_in); |
523 | close(sock_out); | |
0fff78ff | 524 | logit("Protocol major versions differ for %s: %.200s vs. %.200s", |
3c0ef626 | 525 | get_remote_ipaddr(), |
526 | server_version_string, client_version_string); | |
cdd66111 | 527 | cleanup_exit(255); |
3c0ef626 | 528 | } |
529 | } | |
530 | ||
3c0ef626 | 531 | /* Destroy the host and server keys. They will no longer be needed. */ |
532 | void | |
533 | destroy_sensitive_data(void) | |
534 | { | |
535 | int i; | |
536 | ||
537 | if (sensitive_data.server_key) { | |
538 | key_free(sensitive_data.server_key); | |
539 | sensitive_data.server_key = NULL; | |
540 | } | |
e9a17296 | 541 | for (i = 0; i < options.num_host_key_files; i++) { |
3c0ef626 | 542 | if (sensitive_data.host_keys[i]) { |
543 | key_free(sensitive_data.host_keys[i]); | |
544 | sensitive_data.host_keys[i] = NULL; | |
545 | } | |
546 | } | |
547 | sensitive_data.ssh1_host_key = NULL; | |
548 | memset(sensitive_data.ssh1_cookie, 0, SSH_SESSION_KEY_LENGTH); | |
549 | } | |
550 | ||
700318f3 | 551 | /* Demote private to public keys for network child */ |
552 | void | |
553 | demote_sensitive_data(void) | |
554 | { | |
555 | Key *tmp; | |
556 | int i; | |
557 | ||
558 | if (sensitive_data.server_key) { | |
559 | tmp = key_demote(sensitive_data.server_key); | |
560 | key_free(sensitive_data.server_key); | |
561 | sensitive_data.server_key = tmp; | |
562 | } | |
563 | ||
564 | for (i = 0; i < options.num_host_key_files; i++) { | |
565 | if (sensitive_data.host_keys[i]) { | |
566 | tmp = key_demote(sensitive_data.host_keys[i]); | |
567 | key_free(sensitive_data.host_keys[i]); | |
568 | sensitive_data.host_keys[i] = tmp; | |
569 | if (tmp->type == KEY_RSA1) | |
570 | sensitive_data.ssh1_host_key = tmp; | |
571 | } | |
572 | } | |
573 | ||
574 | /* We do not clear ssh1_host key and cookie. XXX - Okay Niels? */ | |
575 | } | |
576 | ||
577 | static void | |
578 | privsep_preauth_child(void) | |
579 | { | |
22616013 | 580 | u_int32_t rnd[256]; |
41b2f314 | 581 | gid_t gidset[1]; |
700318f3 | 582 | |
583 | /* Enable challenge-response authentication for privilege separation */ | |
584 | privsep_challenge_enable(); | |
585 | ||
47686178 | 586 | arc4random_stir(); |
22616013 | 587 | arc4random_buf(rnd, sizeof(rnd)); |
41b2f314 | 588 | RAND_seed(rnd, sizeof(rnd)); |
700318f3 | 589 | |
590 | /* Demote the private keys to public keys. */ | |
591 | demote_sensitive_data(); | |
592 | ||
41b2f314 | 593 | /* Change our root directory */ |
700318f3 | 594 | if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1) |
595 | fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR, | |
596 | strerror(errno)); | |
597 | if (chdir("/") == -1) | |
598 | fatal("chdir(\"/\"): %s", strerror(errno)); | |
599 | ||
600 | /* Drop our privileges */ | |
9108f8d9 | 601 | debug3("privsep user:group %u:%u", (u_int)privsep_pw->pw_uid, |
602 | (u_int)privsep_pw->pw_gid); | |
680cee3b | 603 | #if 0 |
99be0775 | 604 | /* XXX not ready, too heavy after chroot */ |
9108f8d9 | 605 | do_setusercontext(privsep_pw); |
680cee3b | 606 | #else |
9108f8d9 | 607 | gidset[0] = privsep_pw->pw_gid; |
680cee3b | 608 | if (setgroups(1, gidset) < 0) |
609 | fatal("setgroups: %.100s", strerror(errno)); | |
9108f8d9 | 610 | permanently_set_uid(privsep_pw); |
680cee3b | 611 | #endif |
700318f3 | 612 | } |
613 | ||
cdd66111 | 614 | static int |
615 | privsep_preauth(Authctxt *authctxt) | |
700318f3 | 616 | { |
700318f3 | 617 | int status; |
618 | pid_t pid; | |
619 | ||
620 | /* Set up unprivileged child process to deal with network data */ | |
621 | pmonitor = monitor_init(); | |
622 | /* Store a pointer to the kex for later rekeying */ | |
623 | pmonitor->m_pkex = &xxx_kex; | |
624 | ||
625 | pid = fork(); | |
626 | if (pid == -1) { | |
627 | fatal("fork of unprivileged child failed"); | |
628 | } else if (pid != 0) { | |
f5799ae1 | 629 | debug2("Network child is on pid %ld", (long)pid); |
700318f3 | 630 | |
631 | close(pmonitor->m_recvfd); | |
cdd66111 | 632 | pmonitor->m_pid = pid; |
633 | monitor_child_preauth(authctxt, pmonitor); | |
700318f3 | 634 | close(pmonitor->m_sendfd); |
635 | ||
636 | /* Sync memory */ | |
637 | monitor_sync(pmonitor); | |
638 | ||
639 | /* Wait for the child's exit status */ | |
640 | while (waitpid(pid, &status, 0) < 0) | |
641 | if (errno != EINTR) | |
642 | break; | |
cdd66111 | 643 | return (1); |
700318f3 | 644 | } else { |
645 | /* child */ | |
646 | ||
647 | close(pmonitor->m_sendfd); | |
648 | ||
649 | /* Demote the child */ | |
650 | if (getuid() == 0 || geteuid() == 0) | |
651 | privsep_preauth_child(); | |
652 | setproctitle("%s", "[net]"); | |
653 | } | |
cdd66111 | 654 | return (0); |
700318f3 | 655 | } |
656 | ||
657 | static void | |
658 | privsep_postauth(Authctxt *authctxt) | |
659 | { | |
47686178 | 660 | u_int32_t rnd[256]; |
47686178 | 661 | |
41b2f314 | 662 | #ifdef DISABLE_FD_PASSING |
680cee3b | 663 | if (1) { |
664 | #else | |
700318f3 | 665 | if (authctxt->pw->pw_uid == 0 || options.use_login) { |
680cee3b | 666 | #endif |
700318f3 | 667 | /* File descriptor passing is broken or root login */ |
700318f3 | 668 | use_privsep = 0; |
2c06c99b | 669 | goto skip; |
700318f3 | 670 | } |
671 | ||
672 | /* New socket pair */ | |
673 | monitor_reinit(pmonitor); | |
674 | ||
675 | pmonitor->m_pid = fork(); | |
676 | if (pmonitor->m_pid == -1) | |
677 | fatal("fork of unprivileged child failed"); | |
678 | else if (pmonitor->m_pid != 0) { | |
22616013 | 679 | verbose("User child is on pid %ld", (long)pmonitor->m_pid); |
700318f3 | 680 | close(pmonitor->m_recvfd); |
c9f39d2c | 681 | buffer_clear(&loginmsg); |
700318f3 | 682 | monitor_child_postauth(pmonitor); |
683 | ||
684 | /* NEVERREACHED */ | |
685 | exit(0); | |
686 | } | |
687 | ||
688 | close(pmonitor->m_sendfd); | |
689 | ||
690 | /* Demote the private keys to public keys. */ | |
691 | demote_sensitive_data(); | |
692 | ||
47686178 | 693 | arc4random_stir(); |
22616013 | 694 | arc4random_buf(rnd, sizeof(rnd)); |
47686178 | 695 | RAND_seed(rnd, sizeof(rnd)); |
696 | ||
700318f3 | 697 | /* Drop privileges */ |
698 | do_setusercontext(authctxt->pw); | |
699 | ||
2c06c99b | 700 | skip: |
700318f3 | 701 | /* It is safe now to apply the key state */ |
702 | monitor_apply_keystate(pmonitor); | |
665a873d | 703 | |
704 | /* | |
705 | * Tell the packet layer that authentication was successful, since | |
706 | * this information is not part of the key state. | |
707 | */ | |
708 | packet_set_authenticated(); | |
700318f3 | 709 | } |
710 | ||
3c0ef626 | 711 | static char * |
712 | list_hostkey_types(void) | |
713 | { | |
e9a17296 | 714 | Buffer b; |
cdd66111 | 715 | const char *p; |
716 | char *ret; | |
3c0ef626 | 717 | int i; |
e9a17296 | 718 | |
719 | buffer_init(&b); | |
720 | for (i = 0; i < options.num_host_key_files; i++) { | |
3c0ef626 | 721 | Key *key = sensitive_data.host_keys[i]; |
722 | if (key == NULL) | |
723 | continue; | |
e9a17296 | 724 | switch (key->type) { |
3c0ef626 | 725 | case KEY_RSA: |
726 | case KEY_DSA: | |
e9a17296 | 727 | if (buffer_len(&b) > 0) |
728 | buffer_append(&b, ",", 1); | |
729 | p = key_ssh_name(key); | |
730 | buffer_append(&b, p, strlen(p)); | |
3c0ef626 | 731 | break; |
732 | } | |
733 | } | |
e9a17296 | 734 | buffer_append(&b, "\0", 1); |
cdd66111 | 735 | ret = xstrdup(buffer_ptr(&b)); |
e9a17296 | 736 | buffer_free(&b); |
cdd66111 | 737 | debug("list_hostkey_types: %s", ret); |
738 | return ret; | |
3c0ef626 | 739 | } |
740 | ||
700318f3 | 741 | Key * |
3c0ef626 | 742 | get_hostkey_by_type(int type) |
743 | { | |
744 | int i; | |
680cee3b | 745 | |
e9a17296 | 746 | for (i = 0; i < options.num_host_key_files; i++) { |
3c0ef626 | 747 | Key *key = sensitive_data.host_keys[i]; |
748 | if (key != NULL && key->type == type) | |
749 | return key; | |
750 | } | |
751 | return NULL; | |
752 | } | |
753 | ||
700318f3 | 754 | Key * |
755 | get_hostkey_by_index(int ind) | |
756 | { | |
757 | if (ind < 0 || ind >= options.num_host_key_files) | |
758 | return (NULL); | |
759 | return (sensitive_data.host_keys[ind]); | |
760 | } | |
761 | ||
762 | int | |
763 | get_hostkey_index(Key *key) | |
764 | { | |
765 | int i; | |
680cee3b | 766 | |
700318f3 | 767 | for (i = 0; i < options.num_host_key_files; i++) { |
768 | if (key == sensitive_data.host_keys[i]) | |
769 | return (i); | |
770 | } | |
771 | return (-1); | |
772 | } | |
773 | ||
3c0ef626 | 774 | /* |
775 | * returns 1 if connection should be dropped, 0 otherwise. | |
776 | * dropping starts at connection #max_startups_begin with a probability | |
777 | * of (max_startups_rate/100). the probability increases linearly until | |
778 | * all connections are dropped for startups > max_startups | |
779 | */ | |
780 | static int | |
781 | drop_connection(int startups) | |
782 | { | |
996d5e62 | 783 | int p, r; |
3c0ef626 | 784 | |
785 | if (startups < options.max_startups_begin) | |
786 | return 0; | |
787 | if (startups >= options.max_startups) | |
788 | return 1; | |
789 | if (options.max_startups_rate == 100) | |
790 | return 1; | |
791 | ||
792 | p = 100 - options.max_startups_rate; | |
793 | p *= startups - options.max_startups_begin; | |
996d5e62 | 794 | p /= options.max_startups - options.max_startups_begin; |
3c0ef626 | 795 | p += options.max_startups_rate; |
22616013 | 796 | r = arc4random_uniform(100); |
3c0ef626 | 797 | |
996d5e62 | 798 | debug("drop_connection: p %d, r %d", p, r); |
3c0ef626 | 799 | return (r < p) ? 1 : 0; |
800 | } | |
801 | ||
e9a17296 | 802 | static void |
803 | usage(void) | |
804 | { | |
99be0775 | 805 | fprintf(stderr, "%s, %s\n", |
996d5e62 | 806 | SSH_RELEASE, SSLeay_version(SSLEAY_VERSION)); |
99be0775 | 807 | fprintf(stderr, |
22616013 | 808 | "usage: sshd [-46DdeiqTt] [-b bits] [-C connection_spec] [-f config_file]\n" |
809 | " [-g login_grace_time] [-h host_key_file] [-k key_gen_time]\n" | |
810 | " [-o option] [-p port] [-u len]\n" | |
99be0775 | 811 | ); |
e9a17296 | 812 | exit(1); |
813 | } | |
3c0ef626 | 814 | |
c9f39d2c | 815 | static void |
816 | send_rexec_state(int fd, Buffer *conf) | |
817 | { | |
818 | Buffer m; | |
819 | ||
820 | debug3("%s: entering fd = %d config len %d", __func__, fd, | |
821 | buffer_len(conf)); | |
822 | ||
823 | /* | |
824 | * Protocol from reexec master to child: | |
825 | * string configuration | |
826 | * u_int ephemeral_key_follows | |
827 | * bignum e (only if ephemeral_key_follows == 1) | |
828 | * bignum n " | |
829 | * bignum d " | |
830 | * bignum iqmp " | |
831 | * bignum p " | |
832 | * bignum q " | |
2c06c99b | 833 | * string rngseed (only if OpenSSL is not self-seeded) |
c9f39d2c | 834 | */ |
835 | buffer_init(&m); | |
836 | buffer_put_cstring(&m, buffer_ptr(conf)); | |
837 | ||
838 | if (sensitive_data.server_key != NULL && | |
839 | sensitive_data.server_key->type == KEY_RSA1) { | |
840 | buffer_put_int(&m, 1); | |
841 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->e); | |
842 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->n); | |
843 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->d); | |
844 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->iqmp); | |
845 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->p); | |
846 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->q); | |
847 | } else | |
848 | buffer_put_int(&m, 0); | |
849 | ||
2c06c99b | 850 | #ifndef OPENSSL_PRNG_ONLY |
851 | rexec_send_rng_seed(&m); | |
852 | #endif | |
853 | ||
c9f39d2c | 854 | if (ssh_msg_send(fd, 0, &m) == -1) |
855 | fatal("%s: ssh_msg_send failed", __func__); | |
856 | ||
857 | buffer_free(&m); | |
858 | ||
859 | debug3("%s: done", __func__); | |
860 | } | |
861 | ||
862 | static void | |
863 | recv_rexec_state(int fd, Buffer *conf) | |
864 | { | |
865 | Buffer m; | |
866 | char *cp; | |
867 | u_int len; | |
868 | ||
869 | debug3("%s: entering fd = %d", __func__, fd); | |
870 | ||
871 | buffer_init(&m); | |
872 | ||
873 | if (ssh_msg_recv(fd, &m) == -1) | |
874 | fatal("%s: ssh_msg_recv failed", __func__); | |
875 | if (buffer_get_char(&m) != 0) | |
876 | fatal("%s: rexec version mismatch", __func__); | |
877 | ||
878 | cp = buffer_get_string(&m, &len); | |
879 | if (conf != NULL) | |
880 | buffer_append(conf, cp, len + 1); | |
881 | xfree(cp); | |
882 | ||
883 | if (buffer_get_int(&m)) { | |
884 | if (sensitive_data.server_key != NULL) | |
885 | key_free(sensitive_data.server_key); | |
886 | sensitive_data.server_key = key_new_private(KEY_RSA1); | |
887 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->e); | |
888 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->n); | |
889 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->d); | |
890 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->iqmp); | |
891 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->p); | |
892 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->q); | |
893 | rsa_generate_additional_parameters( | |
894 | sensitive_data.server_key->rsa); | |
895 | } | |
2c06c99b | 896 | |
897 | #ifndef OPENSSL_PRNG_ONLY | |
898 | rexec_recv_rng_seed(&m); | |
899 | #endif | |
900 | ||
c9f39d2c | 901 | buffer_free(&m); |
902 | ||
903 | debug3("%s: done", __func__); | |
904 | } | |
905 | ||
9108f8d9 | 906 | /* Accept a connection from inetd */ |
907 | static void | |
908 | server_accept_inetd(int *sock_in, int *sock_out) | |
909 | { | |
910 | int fd; | |
911 | ||
912 | startup_pipe = -1; | |
913 | if (rexeced_flag) { | |
914 | close(REEXEC_CONFIG_PASS_FD); | |
915 | *sock_in = *sock_out = dup(STDIN_FILENO); | |
916 | if (!debug_flag) { | |
917 | startup_pipe = dup(REEXEC_STARTUP_PIPE_FD); | |
918 | close(REEXEC_STARTUP_PIPE_FD); | |
919 | } | |
920 | } else { | |
921 | *sock_in = dup(STDIN_FILENO); | |
922 | *sock_out = dup(STDOUT_FILENO); | |
923 | } | |
924 | /* | |
925 | * We intentionally do not close the descriptors 0, 1, and 2 | |
926 | * as our code for setting the descriptors won't work if | |
927 | * ttyfd happens to be one of those. | |
928 | */ | |
929 | if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { | |
930 | dup2(fd, STDIN_FILENO); | |
931 | dup2(fd, STDOUT_FILENO); | |
932 | if (fd > STDOUT_FILENO) | |
933 | close(fd); | |
934 | } | |
935 | debug("inetd sockets after dupping: %d, %d", *sock_in, *sock_out); | |
936 | } | |
937 | ||
938 | /* | |
939 | * Listen for TCP connections | |
940 | */ | |
941 | static void | |
942 | server_listen(void) | |
943 | { | |
944 | int ret, listen_sock, on = 1; | |
945 | struct addrinfo *ai; | |
946 | char ntop[NI_MAXHOST], strport[NI_MAXSERV]; | |
947 | ||
948 | for (ai = options.listen_addrs; ai; ai = ai->ai_next) { | |
949 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) | |
950 | continue; | |
951 | if (num_listen_socks >= MAX_LISTEN_SOCKS) | |
952 | fatal("Too many listen sockets. " | |
953 | "Enlarge MAX_LISTEN_SOCKS"); | |
954 | if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen, | |
955 | ntop, sizeof(ntop), strport, sizeof(strport), | |
956 | NI_NUMERICHOST|NI_NUMERICSERV)) != 0) { | |
957 | error("getnameinfo failed: %.100s", | |
47686178 | 958 | ssh_gai_strerror(ret)); |
9108f8d9 | 959 | continue; |
960 | } | |
961 | /* Create socket for listening. */ | |
962 | listen_sock = socket(ai->ai_family, ai->ai_socktype, | |
963 | ai->ai_protocol); | |
964 | if (listen_sock < 0) { | |
965 | /* kernel may not support ipv6 */ | |
966 | verbose("socket: %.100s", strerror(errno)); | |
967 | continue; | |
968 | } | |
969 | if (set_nonblock(listen_sock) == -1) { | |
970 | close(listen_sock); | |
971 | continue; | |
972 | } | |
973 | /* | |
974 | * Set socket options. | |
975 | * Allow local port reuse in TIME_WAIT. | |
976 | */ | |
977 | if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR, | |
978 | &on, sizeof(on)) == -1) | |
979 | error("setsockopt SO_REUSEADDR: %s", strerror(errno)); | |
980 | ||
47686178 | 981 | #ifdef IPV6_V6ONLY |
982 | /* Only communicate in IPv6 over AF_INET6 sockets. */ | |
983 | if (ai->ai_family == AF_INET6) { | |
984 | if (setsockopt(listen_sock, IPPROTO_IPV6, IPV6_V6ONLY, | |
985 | &on, sizeof(on)) == -1) | |
986 | error("setsockopt IPV6_V6ONLY: %s", | |
987 | strerror(errno)); | |
988 | } | |
989 | #endif | |
990 | ||
9108f8d9 | 991 | debug("Bind to port %s on %s.", strport, ntop); |
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) { | |
22616013 | 1098 | if (errno != EINTR && errno != EAGAIN && |
1099 | errno != EWOULDBLOCK) | |
9108f8d9 | 1100 | error("accept: %.100s", strerror(errno)); |
1101 | continue; | |
1102 | } | |
1103 | if (unset_nonblock(*newsock) == -1) { | |
1104 | close(*newsock); | |
1105 | continue; | |
1106 | } | |
1107 | if (drop_connection(startups) == 1) { | |
1108 | debug("drop connection #%d", startups); | |
1109 | close(*newsock); | |
1110 | continue; | |
1111 | } | |
1112 | if (pipe(startup_p) == -1) { | |
1113 | close(*newsock); | |
1114 | continue; | |
1115 | } | |
1116 | ||
1117 | if (rexec_flag && socketpair(AF_UNIX, | |
1118 | SOCK_STREAM, 0, config_s) == -1) { | |
1119 | error("reexec socketpair: %s", | |
1120 | strerror(errno)); | |
1121 | close(*newsock); | |
1122 | close(startup_p[0]); | |
1123 | close(startup_p[1]); | |
1124 | continue; | |
1125 | } | |
1126 | ||
1127 | for (j = 0; j < options.max_startups; j++) | |
1128 | if (startup_pipes[j] == -1) { | |
1129 | startup_pipes[j] = startup_p[0]; | |
1130 | if (maxfd < startup_p[0]) | |
1131 | maxfd = startup_p[0]; | |
1132 | startups++; | |
1133 | break; | |
1134 | } | |
1135 | ||
1136 | /* | |
1137 | * Got connection. Fork a child to handle it, unless | |
1138 | * we are in debugging mode. | |
1139 | */ | |
1140 | if (debug_flag) { | |
1141 | /* | |
1142 | * In debugging mode. Close the listening | |
1143 | * socket, and start processing the | |
1144 | * connection without forking. | |
1145 | */ | |
1146 | debug("Server will not fork when running in debugging mode."); | |
1147 | close_listen_socks(); | |
1148 | *sock_in = *newsock; | |
1149 | *sock_out = *newsock; | |
1150 | close(startup_p[0]); | |
1151 | close(startup_p[1]); | |
1152 | startup_pipe = -1; | |
1153 | pid = getpid(); | |
1154 | if (rexec_flag) { | |
1155 | send_rexec_state(config_s[0], | |
1156 | &cfg); | |
1157 | close(config_s[0]); | |
1158 | } | |
1159 | break; | |
1160 | } | |
1161 | ||
1162 | /* | |
1163 | * Normal production daemon. Fork, and have | |
1164 | * the child process the connection. The | |
1165 | * parent continues listening. | |
1166 | */ | |
1167 | platform_pre_fork(); | |
1168 | if ((pid = fork()) == 0) { | |
1169 | /* | |
1170 | * Child. Close the listening and | |
1171 | * max_startup sockets. Start using | |
1172 | * the accepted socket. Reinitialize | |
1173 | * logging (since our pid has changed). | |
1174 | * We break out of the loop to handle | |
1175 | * the connection. | |
1176 | */ | |
1177 | platform_post_fork_child(); | |
1178 | startup_pipe = startup_p[1]; | |
1179 | close_startup_pipes(); | |
1180 | close_listen_socks(); | |
1181 | *sock_in = *newsock; | |
1182 | *sock_out = *newsock; | |
1183 | log_init(__progname, | |
1184 | options.log_level, | |
1185 | options.log_facility, | |
1186 | log_stderr); | |
1187 | if (rexec_flag) | |
1188 | close(config_s[0]); | |
1189 | break; | |
1190 | } | |
1191 | ||
1192 | /* Parent. Stay in the loop. */ | |
1193 | platform_post_fork_parent(pid); | |
1194 | if (pid < 0) | |
1195 | error("fork: %.100s", strerror(errno)); | |
1196 | else | |
1197 | debug("Forked child %ld.", (long)pid); | |
1198 | ||
1199 | close(startup_p[1]); | |
1200 | ||
1201 | if (rexec_flag) { | |
1202 | send_rexec_state(config_s[0], &cfg); | |
1203 | close(config_s[0]); | |
1204 | close(config_s[1]); | |
1205 | } | |
1206 | ||
1207 | /* | |
1208 | * Mark that the key has been used (it | |
1209 | * was "given" to the child). | |
1210 | */ | |
1211 | if ((options.protocol & SSH_PROTO_1) && | |
1212 | key_used == 0) { | |
1213 | /* Schedule server key regeneration alarm. */ | |
1214 | signal(SIGALRM, key_regeneration_alarm); | |
1215 | alarm(options.key_regeneration_time); | |
1216 | key_used = 1; | |
1217 | } | |
1218 | ||
1219 | close(*newsock); | |
1220 | ||
1221 | /* | |
1222 | * Ensure that our random state differs | |
1223 | * from that of the child | |
1224 | */ | |
1225 | arc4random_stir(); | |
1226 | } | |
1227 | ||
1228 | /* child process check (or debug mode) */ | |
1229 | if (num_listen_socks < 0) | |
1230 | break; | |
1231 | } | |
1232 | } | |
1233 | ||
1234 | ||
3c0ef626 | 1235 | /* |
1236 | * Main program for the daemon. | |
1237 | */ | |
1238 | int | |
1239 | main(int ac, char **av) | |
1240 | { | |
1241 | extern char *optarg; | |
1242 | extern int optind; | |
9108f8d9 | 1243 | int opt, i, on = 1; |
c9f39d2c | 1244 | int sock_in = -1, sock_out = -1, newsock = -1; |
3c0ef626 | 1245 | const char *remote_ip; |
22616013 | 1246 | char *test_user = NULL, *test_host = NULL, *test_addr = NULL; |
3c0ef626 | 1247 | int remote_port; |
22616013 | 1248 | char *line, *p, *cp; |
9108f8d9 | 1249 | int config_s[2] = { -1 , -1 }; |
22616013 | 1250 | u_int64_t ibytes, obytes; |
1251 | mode_t new_umask; | |
9cb1827b | 1252 | Key *key; |
cdd66111 | 1253 | Authctxt *authctxt; |
3c0ef626 | 1254 | |
700318f3 | 1255 | #ifdef HAVE_SECUREWARE |
1256 | (void)set_auth_parameters(ac, av); | |
1257 | #endif | |
0fff78ff | 1258 | __progname = ssh_get_progname(av[0]); |
3c0ef626 | 1259 | init_rng(); |
1260 | ||
6a9b3198 | 1261 | /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */ |
3c0ef626 | 1262 | saved_argc = ac; |
c9f39d2c | 1263 | rexec_argc = ac; |
9108f8d9 | 1264 | saved_argv = xcalloc(ac + 1, sizeof(*saved_argv)); |
6a9b3198 | 1265 | for (i = 0; i < ac; i++) |
1266 | saved_argv[i] = xstrdup(av[i]); | |
0fff78ff | 1267 | saved_argv[i] = NULL; |
6a9b3198 | 1268 | |
1269 | #ifndef HAVE_SETPROCTITLE | |
1270 | /* Prepare for later setproctitle emulation */ | |
1271 | compat_init_setproctitle(ac, av); | |
0fff78ff | 1272 | av = saved_argv; |
6a9b3198 | 1273 | #endif |
3c0ef626 | 1274 | |
99be0775 | 1275 | if (geteuid() == 0 && setgroups(0, NULL) == -1) |
1276 | debug("setgroups(): %.200s", strerror(errno)); | |
1277 | ||
2c06c99b | 1278 | /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ |
1279 | sanitise_stdfd(); | |
1280 | ||
3c0ef626 | 1281 | /* Initialize configuration options to their default values. */ |
1282 | initialize_server_options(&options); | |
1283 | ||
1284 | /* Parse command-line arguments. */ | |
22616013 | 1285 | while ((opt = getopt(ac, av, "f:p:b:k:h:g:u:o:C:dDeiqrtQRT46")) != -1) { |
3c0ef626 | 1286 | switch (opt) { |
1287 | case '4': | |
996d5e62 | 1288 | options.address_family = AF_INET; |
3c0ef626 | 1289 | break; |
1290 | case '6': | |
996d5e62 | 1291 | options.address_family = AF_INET6; |
3c0ef626 | 1292 | break; |
1293 | case 'f': | |
1294 | config_file_name = optarg; | |
1295 | break; | |
1296 | case 'd': | |
0fff78ff | 1297 | if (debug_flag == 0) { |
3c0ef626 | 1298 | debug_flag = 1; |
1299 | options.log_level = SYSLOG_LEVEL_DEBUG1; | |
0fff78ff | 1300 | } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) |
3c0ef626 | 1301 | options.log_level++; |
3c0ef626 | 1302 | break; |
1303 | case 'D': | |
1304 | no_daemon_flag = 1; | |
1305 | break; | |
1306 | case 'e': | |
1307 | log_stderr = 1; | |
1308 | break; | |
1309 | case 'i': | |
1310 | inetd_flag = 1; | |
1311 | break; | |
c9f39d2c | 1312 | case 'r': |
1313 | rexec_flag = 0; | |
1314 | break; | |
1315 | case 'R': | |
1316 | rexeced_flag = 1; | |
1317 | inetd_flag = 1; | |
1318 | break; | |
3c0ef626 | 1319 | case 'Q': |
1320 | /* ignored */ | |
1321 | break; | |
1322 | case 'q': | |
1323 | options.log_level = SYSLOG_LEVEL_QUIET; | |
1324 | break; | |
1325 | case 'b': | |
9108f8d9 | 1326 | options.server_key_bits = (int)strtonum(optarg, 256, |
1327 | 32768, NULL); | |
3c0ef626 | 1328 | break; |
1329 | case 'p': | |
1330 | options.ports_from_cmdline = 1; | |
1331 | if (options.num_ports >= MAX_PORTS) { | |
1332 | fprintf(stderr, "too many ports.\n"); | |
1333 | exit(1); | |
1334 | } | |
1335 | options.ports[options.num_ports++] = a2port(optarg); | |
91d9cdd3 | 1336 | if (options.ports[options.num_ports-1] <= 0) { |
3c0ef626 | 1337 | fprintf(stderr, "Bad port number.\n"); |
1338 | exit(1); | |
1339 | } | |
1340 | break; | |
1341 | case 'g': | |
1342 | if ((options.login_grace_time = convtime(optarg)) == -1) { | |
1343 | fprintf(stderr, "Invalid login grace time.\n"); | |
1344 | exit(1); | |
1345 | } | |
1346 | break; | |
1347 | case 'k': | |
1348 | if ((options.key_regeneration_time = convtime(optarg)) == -1) { | |
1349 | fprintf(stderr, "Invalid key regeneration interval.\n"); | |
1350 | exit(1); | |
1351 | } | |
1352 | break; | |
1353 | case 'h': | |
1354 | if (options.num_host_key_files >= MAX_HOSTKEYS) { | |
1355 | fprintf(stderr, "too many host keys.\n"); | |
1356 | exit(1); | |
1357 | } | |
1358 | options.host_key_files[options.num_host_key_files++] = optarg; | |
1359 | break; | |
3c0ef626 | 1360 | case 't': |
1361 | test_flag = 1; | |
1362 | break; | |
22616013 | 1363 | case 'T': |
1364 | test_flag = 2; | |
1365 | break; | |
1366 | case 'C': | |
1367 | cp = optarg; | |
1368 | while ((p = strsep(&cp, ",")) && *p != '\0') { | |
1369 | if (strncmp(p, "addr=", 5) == 0) | |
1370 | test_addr = xstrdup(p + 5); | |
1371 | else if (strncmp(p, "host=", 5) == 0) | |
1372 | test_host = xstrdup(p + 5); | |
1373 | else if (strncmp(p, "user=", 5) == 0) | |
1374 | test_user = xstrdup(p + 5); | |
1375 | else { | |
1376 | fprintf(stderr, "Invalid test " | |
1377 | "mode specification %s\n", p); | |
1378 | exit(1); | |
1379 | } | |
1380 | } | |
1381 | break; | |
3c0ef626 | 1382 | case 'u': |
9108f8d9 | 1383 | utmp_len = (u_int)strtonum(optarg, 0, MAXHOSTNAMELEN+1, NULL); |
41b2f314 | 1384 | if (utmp_len > MAXHOSTNAMELEN) { |
1385 | fprintf(stderr, "Invalid utmp length.\n"); | |
1386 | exit(1); | |
1387 | } | |
3c0ef626 | 1388 | break; |
e9a17296 | 1389 | case 'o': |
cdd66111 | 1390 | line = xstrdup(optarg); |
1391 | if (process_server_config_line(&options, line, | |
9108f8d9 | 1392 | "command-line", 0, NULL, NULL, NULL, NULL) != 0) |
e9a17296 | 1393 | exit(1); |
cdd66111 | 1394 | xfree(line); |
e9a17296 | 1395 | break; |
3c0ef626 | 1396 | case '?': |
1397 | default: | |
e9a17296 | 1398 | usage(); |
1399 | break; | |
3c0ef626 | 1400 | } |
1401 | } | |
c9f39d2c | 1402 | if (rexeced_flag || inetd_flag) |
1403 | rexec_flag = 0; | |
47686178 | 1404 | if (!test_flag && (rexec_flag && (av[0] == NULL || *av[0] != '/'))) |
c9f39d2c | 1405 | fatal("sshd re-exec requires execution with an absolute path"); |
1406 | if (rexeced_flag) | |
1407 | closefrom(REEXEC_MIN_FREE_FD); | |
1408 | else | |
1409 | closefrom(REEXEC_DEVCRYPTO_RESERVED_FD); | |
1410 | ||
3c0ef626 | 1411 | SSLeay_add_all_algorithms(); |
3c0ef626 | 1412 | |
1413 | /* | |
1414 | * Force logging to stderr until we have loaded the private host | |
1415 | * key (unless started from inetd) | |
1416 | */ | |
1417 | log_init(__progname, | |
e9a17296 | 1418 | options.log_level == SYSLOG_LEVEL_NOT_SET ? |
1419 | SYSLOG_LEVEL_INFO : options.log_level, | |
1420 | options.log_facility == SYSLOG_FACILITY_NOT_SET ? | |
1421 | SYSLOG_FACILITY_AUTH : options.log_facility, | |
6a9b3198 | 1422 | log_stderr || !inetd_flag); |
3c0ef626 | 1423 | |
99be0775 | 1424 | /* |
1425 | * Unset KRB5CCNAME, otherwise the user's session may inherit it from | |
1426 | * root's environment | |
665a873d | 1427 | */ |
996d5e62 | 1428 | if (getenv("KRB5CCNAME") != NULL) |
1429 | unsetenv("KRB5CCNAME"); | |
1430 | ||
41b2f314 | 1431 | #ifdef _UNICOS |
c9f39d2c | 1432 | /* Cray can define user privs drop all privs now! |
3c0ef626 | 1433 | * Not needed on PRIV_SU systems! |
1434 | */ | |
1435 | drop_cray_privs(); | |
1436 | #endif | |
1437 | ||
c9f39d2c | 1438 | sensitive_data.server_key = NULL; |
1439 | sensitive_data.ssh1_host_key = NULL; | |
1440 | sensitive_data.have_ssh1_key = 0; | |
1441 | sensitive_data.have_ssh2_key = 0; | |
1442 | ||
22616013 | 1443 | /* |
1444 | * If we're doing an extended config test, make sure we have all of | |
1445 | * the parameters we need. If we're not doing an extended test, | |
1446 | * do not silently ignore connection test params. | |
1447 | */ | |
1448 | if (test_flag >= 2 && | |
1449 | (test_user != NULL || test_host != NULL || test_addr != NULL) | |
1450 | && (test_user == NULL || test_host == NULL || test_addr == NULL)) | |
1451 | fatal("user, host and addr are all required when testing " | |
1452 | "Match configs"); | |
1453 | if (test_flag < 2 && (test_user != NULL || test_host != NULL || | |
1454 | test_addr != NULL)) | |
1455 | fatal("Config test connection parameter (-C) provided without " | |
1456 | "test mode (-T)"); | |
1457 | ||
c9f39d2c | 1458 | /* Fetch our configuration */ |
1459 | buffer_init(&cfg); | |
1460 | if (rexeced_flag) | |
1461 | recv_rexec_state(REEXEC_CONFIG_PASS_FD, &cfg); | |
1462 | else | |
1463 | load_server_config(config_file_name, &cfg); | |
1464 | ||
9108f8d9 | 1465 | parse_server_config(&options, rexeced_flag ? "rexec" : config_file_name, |
1466 | &cfg, NULL, NULL, NULL); | |
3c0ef626 | 1467 | |
2c06c99b | 1468 | seed_rng(); |
1469 | ||
3c0ef626 | 1470 | /* Fill in default values for those options not explicitly set. */ |
1471 | fill_default_server_options(&options); | |
1472 | ||
d4487008 | 1473 | /* challenge-response is implemented via keyboard interactive */ |
1474 | if (options.challenge_response_authentication) | |
1475 | options.kbd_interactive_authentication = 1; | |
1476 | ||
996d5e62 | 1477 | /* set default channel AF */ |
1478 | channel_set_af(options.address_family); | |
1479 | ||
3c0ef626 | 1480 | /* Check that there are no remaining arguments. */ |
1481 | if (optind < ac) { | |
1482 | fprintf(stderr, "Extra argument %s.\n", av[optind]); | |
1483 | exit(1); | |
1484 | } | |
1485 | ||
996d5e62 | 1486 | debug("sshd version %.100s", SSH_RELEASE); |
3c0ef626 | 1487 | |
ff7ec503 | 1488 | /* Store privilege separation user for later use if required. */ |
1489 | if ((privsep_pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) { | |
1490 | if (use_privsep || options.kerberos_authentication) | |
1491 | fatal("Privilege separation user %s does not exist", | |
1492 | SSH_PRIVSEP_USER); | |
1493 | } else { | |
1494 | memset(privsep_pw->pw_passwd, 0, strlen(privsep_pw->pw_passwd)); | |
1495 | privsep_pw = pwcopy(privsep_pw); | |
1496 | xfree(privsep_pw->pw_passwd); | |
1497 | privsep_pw->pw_passwd = xstrdup("*"); | |
1498 | } | |
9108f8d9 | 1499 | endpwent(); |
1500 | ||
3c0ef626 | 1501 | /* load private host keys */ |
9108f8d9 | 1502 | sensitive_data.host_keys = xcalloc(options.num_host_key_files, |
41b2f314 | 1503 | sizeof(Key *)); |
e9a17296 | 1504 | for (i = 0; i < options.num_host_key_files; i++) |
3c0ef626 | 1505 | sensitive_data.host_keys[i] = NULL; |
3c0ef626 | 1506 | |
e9a17296 | 1507 | for (i = 0; i < options.num_host_key_files; i++) { |
3c0ef626 | 1508 | key = key_load_private(options.host_key_files[i], "", NULL); |
1509 | sensitive_data.host_keys[i] = key; | |
1510 | if (key == NULL) { | |
1511 | error("Could not load host key: %s", | |
1512 | options.host_key_files[i]); | |
1513 | sensitive_data.host_keys[i] = NULL; | |
1514 | continue; | |
1515 | } | |
e9a17296 | 1516 | switch (key->type) { |
3c0ef626 | 1517 | case KEY_RSA1: |
1518 | sensitive_data.ssh1_host_key = key; | |
1519 | sensitive_data.have_ssh1_key = 1; | |
1520 | break; | |
1521 | case KEY_RSA: | |
1522 | case KEY_DSA: | |
1523 | sensitive_data.have_ssh2_key = 1; | |
1524 | break; | |
1525 | } | |
1526 | debug("private host key: #%d type %d %s", i, key->type, | |
1527 | key_type(key)); | |
1528 | } | |
1529 | if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) { | |
0fff78ff | 1530 | logit("Disabling protocol version 1. Could not load host key"); |
3c0ef626 | 1531 | options.protocol &= ~SSH_PROTO_1; |
1532 | } | |
1533 | if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) { | |
0fff78ff | 1534 | logit("Disabling protocol version 2. Could not load host key"); |
3c0ef626 | 1535 | options.protocol &= ~SSH_PROTO_2; |
1536 | } | |
1537 | if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) { | |
0fff78ff | 1538 | logit("sshd: no hostkeys available -- exiting."); |
3c0ef626 | 1539 | exit(1); |
1540 | } | |
1541 | ||
1542 | /* Check certain values for sanity. */ | |
1543 | if (options.protocol & SSH_PROTO_1) { | |
1544 | if (options.server_key_bits < 512 || | |
1545 | options.server_key_bits > 32768) { | |
1546 | fprintf(stderr, "Bad server key size.\n"); | |
1547 | exit(1); | |
1548 | } | |
1549 | /* | |
1550 | * Check that server and host key lengths differ sufficiently. This | |
1551 | * is necessary to make double encryption work with rsaref. Oh, I | |
1552 | * hate software patents. I dont know if this can go? Niels | |
1553 | */ | |
1554 | if (options.server_key_bits > | |
680cee3b | 1555 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) - |
1556 | SSH_KEY_BITS_RESERVED && options.server_key_bits < | |
1557 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + | |
1558 | SSH_KEY_BITS_RESERVED) { | |
3c0ef626 | 1559 | options.server_key_bits = |
680cee3b | 1560 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + |
1561 | SSH_KEY_BITS_RESERVED; | |
3c0ef626 | 1562 | debug("Forcing server key to %d bits to make it differ from host key.", |
1563 | options.server_key_bits); | |
1564 | } | |
1565 | } | |
1566 | ||
f5799ae1 | 1567 | if (use_privsep) { |
f5799ae1 | 1568 | struct stat st; |
1569 | ||
f5799ae1 | 1570 | if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) || |
1571 | (S_ISDIR(st.st_mode) == 0)) | |
1572 | fatal("Missing privilege separation directory: %s", | |
1573 | _PATH_PRIVSEP_CHROOT_DIR); | |
41b2f314 | 1574 | |
1575 | #ifdef HAVE_CYGWIN | |
1576 | if (check_ntsec(_PATH_PRIVSEP_CHROOT_DIR) && | |
1577 | (st.st_uid != getuid () || | |
1578 | (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)) | |
1579 | #else | |
680cee3b | 1580 | if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0) |
41b2f314 | 1581 | #endif |
6a9b3198 | 1582 | fatal("%s must be owned by root and not group or " |
1583 | "world-writable.", _PATH_PRIVSEP_CHROOT_DIR); | |
f5799ae1 | 1584 | } |
1585 | ||
22616013 | 1586 | if (test_flag > 1) { |
1587 | if (test_user != NULL && test_addr != NULL && test_host != NULL) | |
1588 | parse_server_match_config(&options, test_user, | |
1589 | test_host, test_addr); | |
1590 | dump_config(&options); | |
1591 | } | |
1592 | ||
3c0ef626 | 1593 | /* Configuration looks good, so exit if in test mode. */ |
1594 | if (test_flag) | |
1595 | exit(0); | |
1596 | ||
700318f3 | 1597 | /* |
1598 | * Clear out any supplemental groups we may have inherited. This | |
1599 | * prevents inadvertent creation of files with bad modes (in the | |
cdd66111 | 1600 | * portable version at least, it's certainly possible for PAM |
1601 | * to create a file, and we can't control the code in every | |
700318f3 | 1602 | * module which might be used). |
1603 | */ | |
1604 | if (setgroups(0, NULL) < 0) | |
1605 | debug("setgroups() failed: %.200s", strerror(errno)); | |
3c0ef626 | 1606 | |
c9f39d2c | 1607 | if (rexec_flag) { |
9108f8d9 | 1608 | rexec_argv = xcalloc(rexec_argc + 2, sizeof(char *)); |
c9f39d2c | 1609 | for (i = 0; i < rexec_argc; i++) { |
1610 | debug("rexec_argv[%d]='%s'", i, saved_argv[i]); | |
1611 | rexec_argv[i] = saved_argv[i]; | |
1612 | } | |
1613 | rexec_argv[rexec_argc] = "-R"; | |
1614 | rexec_argv[rexec_argc + 1] = NULL; | |
1615 | } | |
1616 | ||
22616013 | 1617 | /* Ensure that umask disallows at least group and world write */ |
1618 | new_umask = umask(0077) | 0022; | |
1619 | (void) umask(new_umask); | |
1620 | ||
3c0ef626 | 1621 | /* Initialize the log (it is reinitialized below in case we forked). */ |
996d5e62 | 1622 | if (debug_flag && (!inetd_flag || rexeced_flag)) |
3c0ef626 | 1623 | log_stderr = 1; |
1624 | log_init(__progname, options.log_level, options.log_facility, log_stderr); | |
1625 | ||
1626 | /* | |
1627 | * If not in debugging mode, and not started from inetd, disconnect | |
1628 | * from the controlling terminal, and fork. The original process | |
1629 | * exits. | |
1630 | */ | |
1631 | if (!(debug_flag || inetd_flag || no_daemon_flag)) { | |
1632 | #ifdef TIOCNOTTY | |
1633 | int fd; | |
1634 | #endif /* TIOCNOTTY */ | |
1635 | if (daemon(0, 0) < 0) | |
1636 | fatal("daemon() failed: %.200s", strerror(errno)); | |
1637 | ||
1638 | /* Disconnect from the controlling tty. */ | |
1639 | #ifdef TIOCNOTTY | |
1640 | fd = open(_PATH_TTY, O_RDWR | O_NOCTTY); | |
1641 | if (fd >= 0) { | |
1642 | (void) ioctl(fd, TIOCNOTTY, NULL); | |
1643 | close(fd); | |
1644 | } | |
1645 | #endif /* TIOCNOTTY */ | |
1646 | } | |
1647 | /* Reinitialize the log (because of the fork above). */ | |
1648 | log_init(__progname, options.log_level, options.log_facility, log_stderr); | |
1649 | ||
1650 | /* Initialize the random number generator. */ | |
1651 | arc4random_stir(); | |
1652 | ||
1653 | /* Chdir to the root directory so that the current disk can be | |
1654 | unmounted if desired. */ | |
1655 | chdir("/"); | |
e9a17296 | 1656 | |
3c0ef626 | 1657 | /* ignore SIGPIPE */ |
1658 | signal(SIGPIPE, SIG_IGN); | |
1659 | ||
9108f8d9 | 1660 | /* Get a connection, either from inetd or a listening TCP socket */ |
3c0ef626 | 1661 | if (inetd_flag) { |
9108f8d9 | 1662 | server_accept_inetd(&sock_in, &sock_out); |
3c0ef626 | 1663 | } else { |
9108f8d9 | 1664 | server_listen(); |
3c0ef626 | 1665 | |
1666 | if (options.protocol & SSH_PROTO_1) | |
1667 | generate_ephemeral_server_key(); | |
1668 | ||
3c0ef626 | 1669 | signal(SIGHUP, sighup_handler); |
9108f8d9 | 1670 | signal(SIGCHLD, main_sigchld_handler); |
3c0ef626 | 1671 | signal(SIGTERM, sigterm_handler); |
1672 | signal(SIGQUIT, sigterm_handler); | |
1673 | ||
9108f8d9 | 1674 | /* |
1675 | * Write out the pid file after the sigterm handler | |
1676 | * is setup and the listen sockets are bound | |
1677 | */ | |
3c0ef626 | 1678 | if (!debug_flag) { |
9108f8d9 | 1679 | FILE *f = fopen(options.pid_file, "w"); |
1680 | ||
0fff78ff | 1681 | if (f == NULL) { |
1682 | error("Couldn't create pid file \"%s\": %s", | |
1683 | options.pid_file, strerror(errno)); | |
1684 | } else { | |
f5799ae1 | 1685 | fprintf(f, "%ld\n", (long) getpid()); |
3c0ef626 | 1686 | fclose(f); |
1687 | } | |
1688 | } | |
1689 | ||
9108f8d9 | 1690 | /* Accept a connection and return in a forked child */ |
1691 | server_accept_loop(&sock_in, &sock_out, | |
1692 | &newsock, config_s); | |
3c0ef626 | 1693 | } |
1694 | ||
1695 | /* This is the child processing a new connection. */ | |
99be0775 | 1696 | setproctitle("%s", "[accepted]"); |
3c0ef626 | 1697 | |
700318f3 | 1698 | /* |
1699 | * Create a new session and process group since the 4.4BSD | |
1700 | * setlogin() affects the entire process group. We don't | |
1701 | * want the child to be able to affect the parent. | |
1702 | */ | |
0fff78ff | 1703 | #if !defined(SSHD_ACQUIRES_CTTY) |
6a9b3198 | 1704 | /* |
0fff78ff | 1705 | * If setsid is called, on some platforms sshd will later acquire a |
1706 | * controlling terminal which will result in "could not set | |
1707 | * controlling tty" errors. | |
6a9b3198 | 1708 | */ |
680cee3b | 1709 | if (!debug_flag && !inetd_flag && setsid() < 0) |
700318f3 | 1710 | error("setsid: %.100s", strerror(errno)); |
7435de97 | 1711 | #endif |
700318f3 | 1712 | |
c9f39d2c | 1713 | if (rexec_flag) { |
1714 | int fd; | |
1715 | ||
1716 | debug("rexec start in %d out %d newsock %d pipe %d sock %d", | |
1717 | sock_in, sock_out, newsock, startup_pipe, config_s[0]); | |
1718 | dup2(newsock, STDIN_FILENO); | |
1719 | dup2(STDIN_FILENO, STDOUT_FILENO); | |
1720 | if (startup_pipe == -1) | |
1721 | close(REEXEC_STARTUP_PIPE_FD); | |
1722 | else | |
1723 | dup2(startup_pipe, REEXEC_STARTUP_PIPE_FD); | |
1724 | ||
1725 | dup2(config_s[1], REEXEC_CONFIG_PASS_FD); | |
1726 | close(config_s[1]); | |
1727 | if (startup_pipe != -1) | |
1728 | close(startup_pipe); | |
1729 | ||
1730 | execv(rexec_argv[0], rexec_argv); | |
1731 | ||
1732 | /* Reexec has failed, fall back and continue */ | |
1733 | error("rexec of %s failed: %s", rexec_argv[0], strerror(errno)); | |
1734 | recv_rexec_state(REEXEC_CONFIG_PASS_FD, NULL); | |
1735 | log_init(__progname, options.log_level, | |
1736 | options.log_facility, log_stderr); | |
1737 | ||
1738 | /* Clean up fds */ | |
1739 | startup_pipe = REEXEC_STARTUP_PIPE_FD; | |
1740 | close(config_s[1]); | |
1741 | close(REEXEC_CONFIG_PASS_FD); | |
1742 | newsock = sock_out = sock_in = dup(STDIN_FILENO); | |
1743 | if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { | |
1744 | dup2(fd, STDIN_FILENO); | |
1745 | dup2(fd, STDOUT_FILENO); | |
1746 | if (fd > STDERR_FILENO) | |
1747 | close(fd); | |
1748 | } | |
1749 | debug("rexec cleanup in %d out %d newsock %d pipe %d sock %d", | |
1750 | sock_in, sock_out, newsock, startup_pipe, config_s[0]); | |
1751 | } | |
1752 | ||
3c0ef626 | 1753 | /* |
1754 | * Disable the key regeneration alarm. We will not regenerate the | |
1755 | * key since we are no longer in a position to give it to anyone. We | |
1756 | * will not restart on SIGHUP since it no longer makes sense. | |
1757 | */ | |
1758 | alarm(0); | |
1759 | signal(SIGALRM, SIG_DFL); | |
1760 | signal(SIGHUP, SIG_DFL); | |
1761 | signal(SIGTERM, SIG_DFL); | |
1762 | signal(SIGQUIT, SIG_DFL); | |
1763 | signal(SIGCHLD, SIG_DFL); | |
1764 | signal(SIGINT, SIG_DFL); | |
1765 | ||
3c0ef626 | 1766 | /* |
1767 | * Register our connection. This turns encryption off because we do | |
1768 | * not have a key. | |
1769 | */ | |
1770 | packet_set_connection(sock_in, sock_out); | |
665a873d | 1771 | packet_set_server(); |
3c0ef626 | 1772 | |
665a873d | 1773 | /* Set SO_KEEPALIVE if requested. */ |
1774 | if (options.tcp_keep_alive && packet_connection_is_on_socket() && | |
1775 | setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) < 0) | |
1776 | error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); | |
1777 | ||
1778 | if ((remote_port = get_remote_port()) < 0) { | |
1779 | debug("get_remote_port failed"); | |
1780 | cleanup_exit(255); | |
1781 | } | |
2c06c99b | 1782 | |
1783 | /* | |
1784 | * We use get_canonical_hostname with usedns = 0 instead of | |
1785 | * get_remote_ipaddr here so IP options will be checked. | |
1786 | */ | |
9108f8d9 | 1787 | (void) get_canonical_hostname(0); |
1788 | /* | |
1789 | * The rest of the code depends on the fact that | |
1790 | * get_remote_ipaddr() caches the remote ip, even if | |
1791 | * the socket goes away. | |
1792 | */ | |
1793 | remote_ip = get_remote_ipaddr(); | |
3c0ef626 | 1794 | |
996d5e62 | 1795 | #ifdef SSH_AUDIT_EVENTS |
1796 | audit_connection_from(remote_ip, remote_port); | |
1797 | #endif | |
3c0ef626 | 1798 | #ifdef LIBWRAP |
47686178 | 1799 | allow_severity = options.log_facility|LOG_INFO; |
1800 | deny_severity = options.log_facility|LOG_WARNING; | |
3c0ef626 | 1801 | /* Check whether logins are denied from this host. */ |
c9f39d2c | 1802 | if (packet_connection_is_on_socket()) { |
3c0ef626 | 1803 | struct request_info req; |
1804 | ||
1805 | request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0); | |
1806 | fromhost(&req); | |
1807 | ||
1808 | if (!hosts_access(&req)) { | |
1809 | debug("Connection refused by tcp wrapper"); | |
1810 | refuse(&req); | |
1811 | /* NOTREACHED */ | |
1812 | fatal("libwrap refuse returns"); | |
1813 | } | |
1814 | } | |
1815 | #endif /* LIBWRAP */ | |
1816 | ||
1817 | /* Log the connection. */ | |
1818 | verbose("Connection from %.500s port %d", remote_ip, remote_port); | |
1819 | ||
1820 | /* | |
2c06c99b | 1821 | * We don't want to listen forever unless the other side |
3c0ef626 | 1822 | * successfully authenticates itself. So we set up an alarm which is |
1823 | * cleared after successful authentication. A limit of zero | |
2c06c99b | 1824 | * indicates no limit. Note that we don't set the alarm in debugging |
3c0ef626 | 1825 | * mode; it is just annoying to have the server exit just when you |
1826 | * are about to discover the bug. | |
1827 | */ | |
1828 | signal(SIGALRM, grace_alarm_handler); | |
1829 | if (!debug_flag) | |
1830 | alarm(options.login_grace_time); | |
1831 | ||
1832 | sshd_exchange_identification(sock_in, sock_out); | |
3c0ef626 | 1833 | |
47686178 | 1834 | /* In inetd mode, generate ephemeral key only for proto 1 connections */ |
1835 | if (!compat20 && inetd_flag && sensitive_data.server_key == NULL) | |
1836 | generate_ephemeral_server_key(); | |
1837 | ||
3c0ef626 | 1838 | packet_set_nonblocking(); |
1839 | ||
cdd66111 | 1840 | /* allocate authentication context */ |
9108f8d9 | 1841 | authctxt = xcalloc(1, sizeof(*authctxt)); |
cdd66111 | 1842 | |
dec6d9fe | 1843 | authctxt->loginmsg = &loginmsg; |
1844 | ||
cdd66111 | 1845 | /* XXX global for cleanup, access from other modules */ |
1846 | the_authctxt = authctxt; | |
1847 | ||
996d5e62 | 1848 | /* prepare buffer to collect messages to display to user after login */ |
1849 | buffer_init(&loginmsg); | |
1850 | ||
700318f3 | 1851 | if (use_privsep) |
cdd66111 | 1852 | if (privsep_preauth(authctxt) == 1) |
700318f3 | 1853 | goto authenticated; |
1854 | ||
3c0ef626 | 1855 | /* perform the key exchange */ |
1856 | /* authenticate user and start session */ | |
1857 | if (compat20) { | |
1858 | do_ssh2_kex(); | |
cdd66111 | 1859 | do_authentication2(authctxt); |
3c0ef626 | 1860 | } else { |
1861 | do_ssh1_kex(); | |
cdd66111 | 1862 | do_authentication(authctxt); |
700318f3 | 1863 | } |
1864 | /* | |
1865 | * If we use privilege separation, the unprivileged child transfers | |
1866 | * the current keystate and exits | |
1867 | */ | |
1868 | if (use_privsep) { | |
1869 | mm_send_keystate(pmonitor); | |
1870 | exit(0); | |
1871 | } | |
1872 | ||
1873 | authenticated: | |
2c06c99b | 1874 | /* |
1875 | * Cancel the alarm we set to limit the time taken for | |
1876 | * authentication. | |
1877 | */ | |
1878 | alarm(0); | |
1879 | signal(SIGALRM, SIG_DFL); | |
9108f8d9 | 1880 | authctxt->authenticated = 1; |
2c06c99b | 1881 | if (startup_pipe != -1) { |
1882 | close(startup_pipe); | |
1883 | startup_pipe = -1; | |
1884 | } | |
1885 | ||
996d5e62 | 1886 | #ifdef SSH_AUDIT_EVENTS |
1887 | audit_event(SSH_AUTH_SUCCESS); | |
1888 | #endif | |
1889 | ||
47686178 | 1890 | #ifdef GSSAPI |
1891 | if (options.gss_authentication) { | |
1892 | temporarily_use_uid(authctxt->pw); | |
1893 | ssh_gssapi_storecreds(); | |
1894 | restore_uid(); | |
1895 | } | |
1896 | #endif | |
1897 | #ifdef USE_PAM | |
1898 | if (options.use_pam) { | |
1899 | do_pam_setcred(1); | |
1900 | do_pam_session(); | |
1901 | } | |
1902 | #endif | |
1903 | ||
700318f3 | 1904 | /* |
1905 | * In privilege separation, we fork another child and prepare | |
1906 | * file descriptor passing. | |
1907 | */ | |
1908 | if (use_privsep) { | |
1909 | privsep_postauth(authctxt); | |
1910 | /* the monitor process [priv] will not return */ | |
1911 | if (!compat20) | |
1912 | destroy_sensitive_data(); | |
3c0ef626 | 1913 | } |
700318f3 | 1914 | |
22616013 | 1915 | packet_set_timeout(options.client_alive_interval, |
1916 | options.client_alive_count_max); | |
1917 | ||
cdd66111 | 1918 | /* Start session. */ |
700318f3 | 1919 | do_authenticated(authctxt); |
1920 | ||
3c0ef626 | 1921 | /* The connection has been terminated. */ |
22616013 | 1922 | packet_get_state(MODE_IN, NULL, NULL, NULL, &ibytes); |
1923 | packet_get_state(MODE_OUT, NULL, NULL, NULL, &obytes); | |
1924 | verbose("Transferred: sent %llu, received %llu bytes", obytes, ibytes); | |
1925 | ||
1926 | verbose("Closing connection to %.500s port %d", remote_ip, remote_port); | |
3c0ef626 | 1927 | |
1928 | #ifdef USE_PAM | |
0fff78ff | 1929 | if (options.use_pam) |
1930 | finish_pam(); | |
3c0ef626 | 1931 | #endif /* USE_PAM */ |
1932 | ||
996d5e62 | 1933 | #ifdef SSH_AUDIT_EVENTS |
1934 | PRIVSEP(audit_event(SSH_CONNECTION_CLOSE)); | |
1935 | #endif | |
1936 | ||
3c0ef626 | 1937 | packet_close(); |
700318f3 | 1938 | |
1939 | if (use_privsep) | |
1940 | mm_terminate(); | |
1941 | ||
3c0ef626 | 1942 | exit(0); |
1943 | } | |
1944 | ||
700318f3 | 1945 | /* |
1946 | * Decrypt session_key_int using our private server key and private host key | |
1947 | * (key with larger modulus first). | |
1948 | */ | |
1949 | int | |
1950 | ssh1_session_key(BIGNUM *session_key_int) | |
1951 | { | |
1952 | int rsafail = 0; | |
1953 | ||
9108f8d9 | 1954 | if (BN_cmp(sensitive_data.server_key->rsa->n, |
1955 | sensitive_data.ssh1_host_key->rsa->n) > 0) { | |
700318f3 | 1956 | /* Server key has bigger modulus. */ |
1957 | if (BN_num_bits(sensitive_data.server_key->rsa->n) < | |
9108f8d9 | 1958 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + |
1959 | SSH_KEY_BITS_RESERVED) { | |
1960 | fatal("do_connection: %s: " | |
1961 | "server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d", | |
700318f3 | 1962 | get_remote_ipaddr(), |
1963 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
1964 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), | |
1965 | SSH_KEY_BITS_RESERVED); | |
1966 | } | |
1967 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1968 | sensitive_data.server_key->rsa) <= 0) | |
1969 | rsafail++; | |
1970 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1971 | sensitive_data.ssh1_host_key->rsa) <= 0) | |
1972 | rsafail++; | |
1973 | } else { | |
1974 | /* Host key has bigger modulus (or they are equal). */ | |
1975 | if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) < | |
9108f8d9 | 1976 | BN_num_bits(sensitive_data.server_key->rsa->n) + |
1977 | SSH_KEY_BITS_RESERVED) { | |
1978 | fatal("do_connection: %s: " | |
1979 | "host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d", | |
700318f3 | 1980 | get_remote_ipaddr(), |
1981 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), | |
1982 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
1983 | SSH_KEY_BITS_RESERVED); | |
1984 | } | |
1985 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1986 | sensitive_data.ssh1_host_key->rsa) < 0) | |
1987 | rsafail++; | |
1988 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1989 | sensitive_data.server_key->rsa) < 0) | |
1990 | rsafail++; | |
1991 | } | |
1992 | return (rsafail); | |
1993 | } | |
3c0ef626 | 1994 | /* |
1995 | * SSH1 key exchange | |
1996 | */ | |
1997 | static void | |
1998 | do_ssh1_kex(void) | |
1999 | { | |
2000 | int i, len; | |
3c0ef626 | 2001 | int rsafail = 0; |
2002 | BIGNUM *session_key_int; | |
2003 | u_char session_key[SSH_SESSION_KEY_LENGTH]; | |
2004 | u_char cookie[8]; | |
2005 | u_int cipher_type, auth_mask, protocol_flags; | |
3c0ef626 | 2006 | |
2007 | /* | |
2008 | * Generate check bytes that the client must send back in the user | |
2009 | * packet in order for it to be accepted; this is used to defy ip | |
2010 | * spoofing attacks. Note that this only works against somebody | |
2011 | * doing IP spoofing from a remote machine; any machine on the local | |
2012 | * network can still see outgoing packets and catch the random | |
2013 | * cookie. This only affects rhosts authentication, and this is one | |
2014 | * of the reasons why it is inherently insecure. | |
2015 | */ | |
22616013 | 2016 | arc4random_buf(cookie, sizeof(cookie)); |
3c0ef626 | 2017 | |
2018 | /* | |
2019 | * Send our public key. We include in the packet 64 bits of random | |
2020 | * data that must be matched in the reply in order to prevent IP | |
2021 | * spoofing. | |
2022 | */ | |
2023 | packet_start(SSH_SMSG_PUBLIC_KEY); | |
2024 | for (i = 0; i < 8; i++) | |
2025 | packet_put_char(cookie[i]); | |
2026 | ||
2027 | /* Store our public server RSA key. */ | |
2028 | packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n)); | |
2029 | packet_put_bignum(sensitive_data.server_key->rsa->e); | |
2030 | packet_put_bignum(sensitive_data.server_key->rsa->n); | |
2031 | ||
2032 | /* Store our public host RSA key. */ | |
2033 | packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); | |
2034 | packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e); | |
2035 | packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n); | |
2036 | ||
2037 | /* Put protocol flags. */ | |
2038 | packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN); | |
2039 | ||
2040 | /* Declare which ciphers we support. */ | |
2041 | packet_put_int(cipher_mask_ssh1(0)); | |
2042 | ||
2043 | /* Declare supported authentication types. */ | |
2044 | auth_mask = 0; | |
3c0ef626 | 2045 | if (options.rhosts_rsa_authentication) |
2046 | auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA; | |
2047 | if (options.rsa_authentication) | |
2048 | auth_mask |= 1 << SSH_AUTH_RSA; | |
3c0ef626 | 2049 | if (options.challenge_response_authentication == 1) |
2050 | auth_mask |= 1 << SSH_AUTH_TIS; | |
2051 | if (options.password_authentication) | |
2052 | auth_mask |= 1 << SSH_AUTH_PASSWORD; | |
2053 | packet_put_int(auth_mask); | |
2054 | ||
2055 | /* Send the packet and wait for it to be sent. */ | |
2056 | packet_send(); | |
2057 | packet_write_wait(); | |
2058 | ||
2059 | debug("Sent %d bit server key and %d bit host key.", | |
2060 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
2061 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); | |
2062 | ||
2063 | /* Read clients reply (cipher type and session key). */ | |
e9a17296 | 2064 | packet_read_expect(SSH_CMSG_SESSION_KEY); |
3c0ef626 | 2065 | |
2066 | /* Get cipher type and check whether we accept this. */ | |
2067 | cipher_type = packet_get_char(); | |
2068 | ||
2069 | if (!(cipher_mask_ssh1(0) & (1 << cipher_type))) | |
2070 | packet_disconnect("Warning: client selects unsupported cipher."); | |
2071 | ||
2072 | /* Get check bytes from the packet. These must match those we | |
2073 | sent earlier with the public key packet. */ | |
2074 | for (i = 0; i < 8; i++) | |
2075 | if (cookie[i] != packet_get_char()) | |
2076 | packet_disconnect("IP Spoofing check bytes do not match."); | |
2077 | ||
2078 | debug("Encryption type: %.200s", cipher_name(cipher_type)); | |
2079 | ||
2080 | /* Get the encrypted integer. */ | |
e9a17296 | 2081 | if ((session_key_int = BN_new()) == NULL) |
2082 | fatal("do_ssh1_kex: BN_new failed"); | |
2083 | packet_get_bignum(session_key_int); | |
3c0ef626 | 2084 | |
2085 | protocol_flags = packet_get_int(); | |
2086 | packet_set_protocol_flags(protocol_flags); | |
e9a17296 | 2087 | packet_check_eom(); |
3c0ef626 | 2088 | |
700318f3 | 2089 | /* Decrypt session_key_int using host/server keys */ |
2090 | rsafail = PRIVSEP(ssh1_session_key(session_key_int)); | |
2091 | ||
3c0ef626 | 2092 | /* |
2093 | * Extract session key from the decrypted integer. The key is in the | |
2094 | * least significant 256 bits of the integer; the first byte of the | |
2095 | * key is in the highest bits. | |
2096 | */ | |
2097 | if (!rsafail) { | |
ff7ec503 | 2098 | (void) BN_mask_bits(session_key_int, sizeof(session_key) * 8); |
3c0ef626 | 2099 | len = BN_num_bytes(session_key_int); |
665a873d | 2100 | if (len < 0 || (u_int)len > sizeof(session_key)) { |
ff7ec503 | 2101 | error("do_ssh1_kex: bad session key len from %s: " |
3c0ef626 | 2102 | "session_key_int %d > sizeof(session_key) %lu", |
2103 | get_remote_ipaddr(), len, (u_long)sizeof(session_key)); | |
2104 | rsafail++; | |
2105 | } else { | |
2106 | memset(session_key, 0, sizeof(session_key)); | |
2107 | BN_bn2bin(session_key_int, | |
2108 | session_key + sizeof(session_key) - len); | |
2109 | ||
c9f39d2c | 2110 | derive_ssh1_session_id( |
3c0ef626 | 2111 | sensitive_data.ssh1_host_key->rsa->n, |
c9f39d2c | 2112 | sensitive_data.server_key->rsa->n, |
2113 | cookie, session_id); | |
3c0ef626 | 2114 | /* |
2115 | * Xor the first 16 bytes of the session key with the | |
2116 | * session id. | |
2117 | */ | |
2118 | for (i = 0; i < 16; i++) | |
2119 | session_key[i] ^= session_id[i]; | |
2120 | } | |
2121 | } | |
2122 | if (rsafail) { | |
2123 | int bytes = BN_num_bytes(session_key_int); | |
e9a17296 | 2124 | u_char *buf = xmalloc(bytes); |
3c0ef626 | 2125 | MD5_CTX md; |
2126 | ||
0fff78ff | 2127 | logit("do_connection: generating a fake encryption key"); |
3c0ef626 | 2128 | BN_bn2bin(session_key_int, buf); |
2129 | MD5_Init(&md); | |
2130 | MD5_Update(&md, buf, bytes); | |
2131 | MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); | |
2132 | MD5_Final(session_key, &md); | |
2133 | MD5_Init(&md); | |
2134 | MD5_Update(&md, session_key, 16); | |
2135 | MD5_Update(&md, buf, bytes); | |
2136 | MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); | |
2137 | MD5_Final(session_key + 16, &md); | |
2138 | memset(buf, 0, bytes); | |
2139 | xfree(buf); | |
2140 | for (i = 0; i < 16; i++) | |
2141 | session_id[i] = session_key[i] ^ session_key[i + 16]; | |
2142 | } | |
700318f3 | 2143 | /* Destroy the private and public keys. No longer. */ |
3c0ef626 | 2144 | destroy_sensitive_data(); |
2145 | ||
700318f3 | 2146 | if (use_privsep) |
2147 | mm_ssh1_session_id(session_id); | |
2148 | ||
3c0ef626 | 2149 | /* Destroy the decrypted integer. It is no longer needed. */ |
2150 | BN_clear_free(session_key_int); | |
2151 | ||
2152 | /* Set the session key. From this on all communications will be encrypted. */ | |
2153 | packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type); | |
2154 | ||
2155 | /* Destroy our copy of the session key. It is no longer needed. */ | |
2156 | memset(session_key, 0, sizeof(session_key)); | |
2157 | ||
2158 | debug("Received session key; encryption turned on."); | |
2159 | ||
f5799ae1 | 2160 | /* Send an acknowledgment packet. Note that this packet is sent encrypted. */ |
3c0ef626 | 2161 | packet_start(SSH_SMSG_SUCCESS); |
2162 | packet_send(); | |
2163 | packet_write_wait(); | |
2164 | } | |
2165 | ||
2166 | /* | |
2167 | * SSH2 key exchange: diffie-hellman-group1-sha1 | |
2168 | */ | |
2169 | static void | |
2170 | do_ssh2_kex(void) | |
2171 | { | |
2172 | Kex *kex; | |
2173 | ||
2174 | if (options.ciphers != NULL) { | |
2175 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = | |
2176 | myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; | |
2177 | } | |
2178 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = | |
2179 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]); | |
2180 | myproposal[PROPOSAL_ENC_ALGS_STOC] = | |
2181 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); | |
2182 | ||
2183 | if (options.macs != NULL) { | |
2184 | myproposal[PROPOSAL_MAC_ALGS_CTOS] = | |
2185 | myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; | |
2186 | } | |
665a873d | 2187 | if (options.compression == COMP_NONE) { |
f5799ae1 | 2188 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = |
2189 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "none"; | |
665a873d | 2190 | } else if (options.compression == COMP_DELAYED) { |
2191 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = | |
2192 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com"; | |
f5799ae1 | 2193 | } |
9108f8d9 | 2194 | |
3c0ef626 | 2195 | myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = list_hostkey_types(); |
2196 | ||
2197 | /* start key exchange */ | |
2198 | kex = kex_setup(myproposal); | |
6a9b3198 | 2199 | kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server; |
c9f39d2c | 2200 | kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server; |
6a9b3198 | 2201 | kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; |
9108f8d9 | 2202 | kex->kex[KEX_DH_GEX_SHA256] = kexgex_server; |
3c0ef626 | 2203 | kex->server = 1; |
2204 | kex->client_version_string=client_version_string; | |
2205 | kex->server_version_string=server_version_string; | |
2206 | kex->load_host_key=&get_hostkey_by_type; | |
700318f3 | 2207 | kex->host_key_index=&get_hostkey_index; |
3c0ef626 | 2208 | |
2209 | xxx_kex = kex; | |
2210 | ||
2211 | dispatch_run(DISPATCH_BLOCK, &kex->done, kex); | |
2212 | ||
2213 | session_id2 = kex->session_id; | |
2214 | session_id2_len = kex->session_id_len; | |
2215 | ||
2216 | #ifdef DEBUG_KEXDH | |
2217 | /* send 1st encrypted/maced/compressed message */ | |
2218 | packet_start(SSH2_MSG_IGNORE); | |
2219 | packet_put_cstring("markus"); | |
2220 | packet_send(); | |
2221 | packet_write_wait(); | |
2222 | #endif | |
2223 | debug("KEX done"); | |
2224 | } | |
cdd66111 | 2225 | |
2226 | /* server specific fatal cleanup */ | |
2227 | void | |
2228 | cleanup_exit(int i) | |
2229 | { | |
2230 | if (the_authctxt) | |
2231 | do_cleanup(the_authctxt); | |
996d5e62 | 2232 | #ifdef SSH_AUDIT_EVENTS |
2233 | /* done after do_cleanup so it can cancel the PAM auth 'thread' */ | |
2234 | if (!use_privsep || mm_is_monitor()) | |
2235 | audit_event(SSH_CONNECTION_ABANDON); | |
2236 | #endif | |
cdd66111 | 2237 | _exit(i); |
2238 | } |