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8efc0c15 | 1 | /* |
5260325f | 2 | * Author: Tatu Ylonen <ylo@cs.hut.fi> |
3 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland | |
4 | * All rights reserved | |
bcbf86ec | 5 | * This program is the ssh daemon. It listens for connections from clients, |
6 | * and performs authentication, executes use commands or shell, and forwards | |
5260325f | 7 | * information to/from the application to the user client over an encrypted |
bcbf86ec | 8 | * connection. This can also handle forwarding of X11, TCP/IP, and |
9 | * authentication agent connections. | |
e78a59f5 | 10 | * |
bcbf86ec | 11 | * As far as I am concerned, the code I have written for this software |
12 | * can be used freely for any purpose. Any derived versions of this | |
13 | * software must be clearly marked as such, and if the derived work is | |
14 | * incompatible with the protocol description in the RFC file, it must be | |
15 | * called by a name other than "ssh" or "Secure Shell". | |
16 | * | |
17 | * SSH2 implementation: | |
1853d1ef | 18 | * Privilege Separation: |
bcbf86ec | 19 | * |
1853d1ef | 20 | * Copyright (c) 2000, 2001, 2002 Markus Friedl. All rights reserved. |
21 | * Copyright (c) 2002 Niels Provos. All rights reserved. | |
bcbf86ec | 22 | * |
23 | * Redistribution and use in source and binary forms, with or without | |
24 | * modification, are permitted provided that the following conditions | |
25 | * are met: | |
26 | * 1. Redistributions of source code must retain the above copyright | |
27 | * notice, this list of conditions and the following disclaimer. | |
28 | * 2. Redistributions in binary form must reproduce the above copyright | |
29 | * notice, this list of conditions and the following disclaimer in the | |
30 | * documentation and/or other materials provided with the distribution. | |
31 | * | |
32 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR | |
33 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES | |
34 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. | |
35 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, | |
36 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
37 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
38 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
39 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
40 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF | |
41 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
5260325f | 42 | */ |
8efc0c15 | 43 | |
44 | #include "includes.h" | |
bd7c69ea | 45 | RCSID("$OpenBSD: sshd.c,v 1.320 2006/02/10 00:27:13 stevesk Exp $"); |
46 | ||
47 | #include <sys/ioctl.h> | |
a75f5360 | 48 | |
49 | #include <paths.h> | |
8efc0c15 | 50 | |
42f11eb2 | 51 | #include <openssl/dh.h> |
52 | #include <openssl/bn.h> | |
436c347c | 53 | #include <openssl/md5.h> |
1853d1ef | 54 | #include <openssl/rand.h> |
6e879cb4 | 55 | #ifdef HAVE_SECUREWARE |
56 | #include <sys/security.h> | |
57 | #include <prot.h> | |
58 | #endif | |
42f11eb2 | 59 | |
60 | #include "ssh.h" | |
61 | #include "ssh1.h" | |
62 | #include "ssh2.h" | |
8efc0c15 | 63 | #include "xmalloc.h" |
64 | #include "rsa.h" | |
1729c161 | 65 | #include "sshpty.h" |
8efc0c15 | 66 | #include "packet.h" |
42f11eb2 | 67 | #include "log.h" |
8efc0c15 | 68 | #include "servconf.h" |
69 | #include "uidswap.h" | |
70 | #include "compat.h" | |
7368a6c8 | 71 | #include "buffer.h" |
b9a549d7 | 72 | #include "bufaux.h" |
42f11eb2 | 73 | #include "cipher.h" |
e78a59f5 | 74 | #include "kex.h" |
7368a6c8 | 75 | #include "key.h" |
94ec8c6b | 76 | #include "dh.h" |
e78a59f5 | 77 | #include "myproposal.h" |
a306f2dd | 78 | #include "authfile.h" |
42f11eb2 | 79 | #include "pathnames.h" |
80 | #include "atomicio.h" | |
81 | #include "canohost.h" | |
82 | #include "auth.h" | |
83 | #include "misc.h" | |
b9a549d7 | 84 | #include "msg.h" |
a5c9ffdb | 85 | #include "dispatch.h" |
e4d7f734 | 86 | #include "channels.h" |
1b34c1b3 | 87 | #include "session.h" |
1853d1ef | 88 | #include "monitor_mm.h" |
89 | #include "monitor.h" | |
90 | #include "monitor_wrap.h" | |
91 | #include "monitor_fdpass.h" | |
8efc0c15 | 92 | |
93 | #ifdef LIBWRAP | |
94 | #include <tcpd.h> | |
95 | #include <syslog.h> | |
96 | int allow_severity = LOG_INFO; | |
97 | int deny_severity = LOG_WARNING; | |
98 | #endif /* LIBWRAP */ | |
99 | ||
100 | #ifndef O_NOCTTY | |
101 | #define O_NOCTTY 0 | |
102 | #endif | |
103 | ||
b250e837 | 104 | /* Re-exec fds */ |
105 | #define REEXEC_DEVCRYPTO_RESERVED_FD (STDERR_FILENO + 1) | |
106 | #define REEXEC_STARTUP_PIPE_FD (STDERR_FILENO + 2) | |
107 | #define REEXEC_CONFIG_PASS_FD (STDERR_FILENO + 3) | |
108 | #define REEXEC_MIN_FREE_FD (STDERR_FILENO + 4) | |
109 | ||
260d427b | 110 | extern char *__progname; |
260d427b | 111 | |
8efc0c15 | 112 | /* Server configuration options. */ |
113 | ServerOptions options; | |
114 | ||
115 | /* Name of the server configuration file. */ | |
42f11eb2 | 116 | char *config_file_name = _PATH_SERVER_CONFIG_FILE; |
8efc0c15 | 117 | |
5260325f | 118 | /* |
119 | * Debug mode flag. This can be set on the command line. If debug | |
120 | * mode is enabled, extra debugging output will be sent to the system | |
121 | * log, the daemon will not go to background, and will exit after processing | |
122 | * the first connection. | |
123 | */ | |
8efc0c15 | 124 | int debug_flag = 0; |
125 | ||
f87f09aa | 126 | /* Flag indicating that the daemon should only test the configuration and keys. */ |
127 | int test_flag = 0; | |
128 | ||
8efc0c15 | 129 | /* Flag indicating that the daemon is being started from inetd. */ |
130 | int inetd_flag = 0; | |
131 | ||
0b6fbf03 | 132 | /* Flag indicating that sshd should not detach and become a daemon. */ |
133 | int no_daemon_flag = 0; | |
134 | ||
6a17f9c2 | 135 | /* debug goes to stderr unless inetd_flag is set */ |
136 | int log_stderr = 0; | |
137 | ||
8efc0c15 | 138 | /* Saved arguments to main(). */ |
139 | char **saved_argv; | |
4d33e531 | 140 | int saved_argc; |
8efc0c15 | 141 | |
b9a549d7 | 142 | /* re-exec */ |
143 | int rexeced_flag = 0; | |
144 | int rexec_flag = 1; | |
145 | int rexec_argc = 0; | |
146 | char **rexec_argv; | |
147 | ||
aa3378df | 148 | /* |
48e671d5 | 149 | * The sockets that the server is listening; this is used in the SIGHUP |
150 | * signal handler. | |
aa3378df | 151 | */ |
48e671d5 | 152 | #define MAX_LISTEN_SOCKS 16 |
153 | int listen_socks[MAX_LISTEN_SOCKS]; | |
154 | int num_listen_socks = 0; | |
8efc0c15 | 155 | |
aa3378df | 156 | /* |
157 | * the client's version string, passed by sshd2 in compat mode. if != NULL, | |
158 | * sshd will skip the version-number exchange | |
159 | */ | |
5260325f | 160 | char *client_version_string = NULL; |
7368a6c8 | 161 | char *server_version_string = NULL; |
8efc0c15 | 162 | |
7a37c112 | 163 | /* for rekeying XXX fixme */ |
164 | Kex *xxx_kex; | |
165 | ||
aa3378df | 166 | /* |
167 | * Any really sensitive data in the application is contained in this | |
168 | * structure. The idea is that this structure could be locked into memory so | |
169 | * that the pages do not get written into swap. However, there are some | |
170 | * problems. The private key contains BIGNUMs, and we do not (in principle) | |
171 | * have access to the internals of them, and locking just the structure is | |
172 | * not very useful. Currently, memory locking is not implemented. | |
173 | */ | |
5260325f | 174 | struct { |
cb7bd922 | 175 | Key *server_key; /* ephemeral server key */ |
fa08c86b | 176 | Key *ssh1_host_key; /* ssh1 host key */ |
177 | Key **host_keys; /* all private host keys */ | |
178 | int have_ssh1_key; | |
179 | int have_ssh2_key; | |
00be5382 | 180 | u_char ssh1_cookie[SSH_SESSION_KEY_LENGTH]; |
8efc0c15 | 181 | } sensitive_data; |
182 | ||
aa3378df | 183 | /* |
59c97189 | 184 | * Flag indicating whether the RSA server key needs to be regenerated. |
185 | * Is set in the SIGALRM handler and cleared when the key is regenerated. | |
aa3378df | 186 | */ |
7a934d1b | 187 | static volatile sig_atomic_t key_do_regen = 0; |
8efc0c15 | 188 | |
c9130033 | 189 | /* This is set to true when a signal is received. */ |
7a934d1b | 190 | static volatile sig_atomic_t received_sighup = 0; |
191 | static volatile sig_atomic_t received_sigterm = 0; | |
8efc0c15 | 192 | |
7368a6c8 | 193 | /* session identifier, used by RSA-auth */ |
1e3b8b07 | 194 | u_char session_id[16]; |
e7c0f9d5 | 195 | |
a306f2dd | 196 | /* same for ssh2 */ |
1e3b8b07 | 197 | u_char *session_id2 = NULL; |
a27002e5 | 198 | u_int session_id2_len = 0; |
a306f2dd | 199 | |
c345cf9d | 200 | /* record remote hostname or ip */ |
1e3b8b07 | 201 | u_int utmp_len = MAXHOSTNAMELEN; |
c345cf9d | 202 | |
7ace8c3b | 203 | /* options.max_startup sized array of fd ints */ |
204 | int *startup_pipes = NULL; | |
205 | int startup_pipe; /* in child */ | |
206 | ||
1853d1ef | 207 | /* variables used for privilege separation */ |
98a58eda | 208 | int use_privsep; |
a9b33b95 | 209 | struct monitor *pmonitor = NULL; |
1853d1ef | 210 | |
2362db19 | 211 | /* global authentication context */ |
212 | Authctxt *the_authctxt = NULL; | |
213 | ||
be2ca0c9 | 214 | /* message to be displayed after login */ |
215 | Buffer loginmsg; | |
216 | ||
7368a6c8 | 217 | /* Prototypes for various functions defined later in this file. */ |
396c147e | 218 | void destroy_sensitive_data(void); |
1853d1ef | 219 | void demote_sensitive_data(void); |
c8d54615 | 220 | |
396c147e | 221 | static void do_ssh1_kex(void); |
222 | static void do_ssh2_kex(void); | |
94ec8c6b | 223 | |
48e671d5 | 224 | /* |
225 | * Close all listening sockets | |
226 | */ | |
396c147e | 227 | static void |
48e671d5 | 228 | close_listen_socks(void) |
229 | { | |
230 | int i; | |
e424e241 | 231 | |
48e671d5 | 232 | for (i = 0; i < num_listen_socks; i++) |
233 | close(listen_socks[i]); | |
234 | num_listen_socks = -1; | |
235 | } | |
236 | ||
7ace8c3b | 237 | static void |
238 | close_startup_pipes(void) | |
239 | { | |
240 | int i; | |
e424e241 | 241 | |
7ace8c3b | 242 | if (startup_pipes) |
243 | for (i = 0; i < options.max_startups; i++) | |
244 | if (startup_pipes[i] != -1) | |
245 | close(startup_pipes[i]); | |
246 | } | |
247 | ||
5260325f | 248 | /* |
249 | * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP; | |
250 | * the effect is to reread the configuration file (and to regenerate | |
251 | * the server key). | |
252 | */ | |
396c147e | 253 | static void |
5260325f | 254 | sighup_handler(int sig) |
8efc0c15 | 255 | { |
6056eb35 | 256 | int save_errno = errno; |
257 | ||
5260325f | 258 | received_sighup = 1; |
259 | signal(SIGHUP, sighup_handler); | |
6056eb35 | 260 | errno = save_errno; |
8efc0c15 | 261 | } |
262 | ||
5260325f | 263 | /* |
264 | * Called from the main program after receiving SIGHUP. | |
265 | * Restarts the server. | |
266 | */ | |
396c147e | 267 | static void |
5ca51e19 | 268 | sighup_restart(void) |
8efc0c15 | 269 | { |
bbe88b6d | 270 | logit("Received SIGHUP; restarting."); |
48e671d5 | 271 | close_listen_socks(); |
7ace8c3b | 272 | close_startup_pipes(); |
5260325f | 273 | execv(saved_argv[0], saved_argv); |
bbe88b6d | 274 | logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0], |
e424e241 | 275 | strerror(errno)); |
5260325f | 276 | exit(1); |
8efc0c15 | 277 | } |
278 | ||
5260325f | 279 | /* |
280 | * Generic signal handler for terminating signals in the master daemon. | |
5260325f | 281 | */ |
396c147e | 282 | static void |
5260325f | 283 | sigterm_handler(int sig) |
8efc0c15 | 284 | { |
c9130033 | 285 | received_sigterm = sig; |
8efc0c15 | 286 | } |
287 | ||
5260325f | 288 | /* |
289 | * SIGCHLD handler. This is called whenever a child dies. This will then | |
c9130033 | 290 | * reap any zombies left by exited children. |
5260325f | 291 | */ |
396c147e | 292 | static void |
5260325f | 293 | main_sigchld_handler(int sig) |
8efc0c15 | 294 | { |
5260325f | 295 | int save_errno = errno; |
e424e241 | 296 | pid_t pid; |
5260325f | 297 | int status; |
5ad13cd7 | 298 | |
8c38e88b | 299 | while ((pid = waitpid(-1, &status, WNOHANG)) > 0 || |
300 | (pid < 0 && errno == EINTR)) | |
5260325f | 301 | ; |
5ad13cd7 | 302 | |
5260325f | 303 | signal(SIGCHLD, main_sigchld_handler); |
304 | errno = save_errno; | |
8efc0c15 | 305 | } |
306 | ||
5260325f | 307 | /* |
308 | * Signal handler for the alarm after the login grace period has expired. | |
309 | */ | |
396c147e | 310 | static void |
5260325f | 311 | grace_alarm_handler(int sig) |
8efc0c15 | 312 | { |
c9130033 | 313 | /* XXX no idea how fix this signal handler */ |
314 | ||
a9b33b95 | 315 | if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0) |
316 | kill(pmonitor->m_pid, SIGALRM); | |
317 | ||
5260325f | 318 | /* Log error and exit. */ |
26b9a3d2 | 319 | fatal("Timeout before authentication for %s", get_remote_ipaddr()); |
5260325f | 320 | } |
8efc0c15 | 321 | |
5260325f | 322 | /* |
323 | * Signal handler for the key regeneration alarm. Note that this | |
324 | * alarm only occurs in the daemon waiting for connections, and it does not | |
325 | * do anything with the private key or random state before forking. | |
326 | * Thus there should be no concurrency control/asynchronous execution | |
327 | * problems. | |
328 | */ | |
396c147e | 329 | static void |
cb7bd922 | 330 | generate_ephemeral_server_key(void) |
fa08c86b | 331 | { |
7fdc56c5 | 332 | u_int32_t rnd = 0; |
00be5382 | 333 | int i; |
334 | ||
cd332296 | 335 | verbose("Generating %s%d bit RSA key.", |
76ca7b01 | 336 | sensitive_data.server_key ? "new " : "", options.server_key_bits); |
fa08c86b | 337 | if (sensitive_data.server_key != NULL) |
338 | key_free(sensitive_data.server_key); | |
cd332296 | 339 | sensitive_data.server_key = key_generate(KEY_RSA1, |
76ca7b01 | 340 | options.server_key_bits); |
341 | verbose("RSA key generation complete."); | |
00be5382 | 342 | |
343 | for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) { | |
344 | if (i % 4 == 0) | |
7fdc56c5 | 345 | rnd = arc4random(); |
346 | sensitive_data.ssh1_cookie[i] = rnd & 0xff; | |
347 | rnd >>= 8; | |
00be5382 | 348 | } |
349 | arc4random_stir(); | |
fa08c86b | 350 | } |
f546c780 | 351 | |
396c147e | 352 | static void |
5260325f | 353 | key_regeneration_alarm(int sig) |
354 | { | |
355 | int save_errno = errno; | |
e424e241 | 356 | |
59c97189 | 357 | signal(SIGALRM, SIG_DFL); |
5260325f | 358 | errno = save_errno; |
59c97189 | 359 | key_do_regen = 1; |
5260325f | 360 | } |
8efc0c15 | 361 | |
396c147e | 362 | static void |
7368a6c8 | 363 | sshd_exchange_identification(int sock_in, int sock_out) |
364 | { | |
2ceb8101 | 365 | u_int i; |
366 | int mismatch; | |
7368a6c8 | 367 | int remote_major, remote_minor; |
a8be9f80 | 368 | int major, minor; |
7368a6c8 | 369 | char *s; |
370 | char buf[256]; /* Must not be larger than remote_version. */ | |
371 | char remote_version[256]; /* Must be at least as big as buf. */ | |
372 | ||
a8be9f80 | 373 | if ((options.protocol & SSH_PROTO_1) && |
374 | (options.protocol & SSH_PROTO_2)) { | |
375 | major = PROTOCOL_MAJOR_1; | |
376 | minor = 99; | |
377 | } else if (options.protocol & SSH_PROTO_2) { | |
378 | major = PROTOCOL_MAJOR_2; | |
379 | minor = PROTOCOL_MINOR_2; | |
380 | } else { | |
381 | major = PROTOCOL_MAJOR_1; | |
382 | minor = PROTOCOL_MINOR_1; | |
383 | } | |
384 | snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", major, minor, SSH_VERSION); | |
7368a6c8 | 385 | server_version_string = xstrdup(buf); |
386 | ||
7b390973 | 387 | /* Send our protocol version identification. */ |
388 | if (atomicio(vwrite, sock_out, server_version_string, | |
389 | strlen(server_version_string)) | |
390 | != strlen(server_version_string)) { | |
391 | logit("Could not write ident string to %s", get_remote_ipaddr()); | |
2362db19 | 392 | cleanup_exit(255); |
7b390973 | 393 | } |
394 | ||
395 | /* Read other sides version identification. */ | |
396 | memset(buf, 0, sizeof(buf)); | |
397 | for (i = 0; i < sizeof(buf) - 1; i++) { | |
398 | if (atomicio(read, sock_in, &buf[i], 1) != 1) { | |
399 | logit("Did not receive identification string from %s", | |
400 | get_remote_ipaddr()); | |
2362db19 | 401 | cleanup_exit(255); |
7368a6c8 | 402 | } |
7b390973 | 403 | if (buf[i] == '\r') { |
404 | buf[i] = 0; | |
405 | /* Kludge for F-Secure Macintosh < 1.0.2 */ | |
406 | if (i == 12 && | |
407 | strncmp(buf, "SSH-1.5-W1.0", 12) == 0) | |
7368a6c8 | 408 | break; |
7b390973 | 409 | continue; |
410 | } | |
411 | if (buf[i] == '\n') { | |
412 | buf[i] = 0; | |
413 | break; | |
7368a6c8 | 414 | } |
7368a6c8 | 415 | } |
7b390973 | 416 | buf[sizeof(buf) - 1] = 0; |
417 | client_version_string = xstrdup(buf); | |
7368a6c8 | 418 | |
419 | /* | |
420 | * Check that the versions match. In future this might accept | |
421 | * several versions and set appropriate flags to handle them. | |
422 | */ | |
423 | if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n", | |
424 | &remote_major, &remote_minor, remote_version) != 3) { | |
6ae2364d | 425 | s = "Protocol mismatch.\n"; |
dc54438a | 426 | (void) atomicio(vwrite, sock_out, s, strlen(s)); |
7368a6c8 | 427 | close(sock_in); |
428 | close(sock_out); | |
bbe88b6d | 429 | logit("Bad protocol version identification '%.100s' from %s", |
7368a6c8 | 430 | client_version_string, get_remote_ipaddr()); |
2362db19 | 431 | cleanup_exit(255); |
7368a6c8 | 432 | } |
433 | debug("Client protocol version %d.%d; client software version %.100s", | |
184eed6a | 434 | remote_major, remote_minor, remote_version); |
7368a6c8 | 435 | |
e78a59f5 | 436 | compat_datafellows(remote_version); |
437 | ||
9a87e2ac | 438 | if (datafellows & SSH_BUG_PROBE) { |
bbe88b6d | 439 | logit("probed from %s with %s. Don't panic.", |
9a87e2ac | 440 | get_remote_ipaddr(), client_version_string); |
2362db19 | 441 | cleanup_exit(255); |
9a87e2ac | 442 | } |
443 | ||
3a1c54d4 | 444 | if (datafellows & SSH_BUG_SCANNER) { |
bbe88b6d | 445 | logit("scanned from %s with %s. Don't panic.", |
3a1c54d4 | 446 | get_remote_ipaddr(), client_version_string); |
2362db19 | 447 | cleanup_exit(255); |
3a1c54d4 | 448 | } |
449 | ||
a8be9f80 | 450 | mismatch = 0; |
6aacefa7 | 451 | switch (remote_major) { |
7368a6c8 | 452 | case 1: |
a306f2dd | 453 | if (remote_minor == 99) { |
454 | if (options.protocol & SSH_PROTO_2) | |
455 | enable_compat20(); | |
456 | else | |
457 | mismatch = 1; | |
458 | break; | |
459 | } | |
a8be9f80 | 460 | if (!(options.protocol & SSH_PROTO_1)) { |
461 | mismatch = 1; | |
462 | break; | |
463 | } | |
7368a6c8 | 464 | if (remote_minor < 3) { |
089fbbd2 | 465 | packet_disconnect("Your ssh version is too old and " |
7368a6c8 | 466 | "is no longer supported. Please install a newer version."); |
467 | } else if (remote_minor == 3) { | |
468 | /* note that this disables agent-forwarding */ | |
469 | enable_compat13(); | |
470 | } | |
a8be9f80 | 471 | break; |
e78a59f5 | 472 | case 2: |
a8be9f80 | 473 | if (options.protocol & SSH_PROTO_2) { |
e78a59f5 | 474 | enable_compat20(); |
475 | break; | |
476 | } | |
477 | /* FALLTHROUGH */ | |
6ae2364d | 478 | default: |
a8be9f80 | 479 | mismatch = 1; |
480 | break; | |
481 | } | |
482 | chop(server_version_string); | |
a8be9f80 | 483 | debug("Local version string %.200s", server_version_string); |
484 | ||
485 | if (mismatch) { | |
7368a6c8 | 486 | s = "Protocol major versions differ.\n"; |
dc54438a | 487 | (void) atomicio(vwrite, sock_out, s, strlen(s)); |
7368a6c8 | 488 | close(sock_in); |
489 | close(sock_out); | |
bbe88b6d | 490 | logit("Protocol major versions differ for %s: %.200s vs. %.200s", |
a8be9f80 | 491 | get_remote_ipaddr(), |
492 | server_version_string, client_version_string); | |
2362db19 | 493 | cleanup_exit(255); |
7368a6c8 | 494 | } |
a306f2dd | 495 | } |
496 | ||
fa08c86b | 497 | /* Destroy the host and server keys. They will no longer be needed. */ |
a306f2dd | 498 | void |
499 | destroy_sensitive_data(void) | |
500 | { | |
fa08c86b | 501 | int i; |
502 | ||
503 | if (sensitive_data.server_key) { | |
504 | key_free(sensitive_data.server_key); | |
505 | sensitive_data.server_key = NULL; | |
506 | } | |
184eed6a | 507 | for (i = 0; i < options.num_host_key_files; i++) { |
fa08c86b | 508 | if (sensitive_data.host_keys[i]) { |
509 | key_free(sensitive_data.host_keys[i]); | |
510 | sensitive_data.host_keys[i] = NULL; | |
511 | } | |
512 | } | |
513 | sensitive_data.ssh1_host_key = NULL; | |
00be5382 | 514 | memset(sensitive_data.ssh1_cookie, 0, SSH_SESSION_KEY_LENGTH); |
fa08c86b | 515 | } |
fa08c86b | 516 | |
1853d1ef | 517 | /* Demote private to public keys for network child */ |
518 | void | |
519 | demote_sensitive_data(void) | |
520 | { | |
521 | Key *tmp; | |
522 | int i; | |
523 | ||
524 | if (sensitive_data.server_key) { | |
525 | tmp = key_demote(sensitive_data.server_key); | |
526 | key_free(sensitive_data.server_key); | |
527 | sensitive_data.server_key = tmp; | |
528 | } | |
529 | ||
530 | for (i = 0; i < options.num_host_key_files; i++) { | |
531 | if (sensitive_data.host_keys[i]) { | |
532 | tmp = key_demote(sensitive_data.host_keys[i]); | |
533 | key_free(sensitive_data.host_keys[i]); | |
534 | sensitive_data.host_keys[i] = tmp; | |
535 | if (tmp->type == KEY_RSA1) | |
536 | sensitive_data.ssh1_host_key = tmp; | |
537 | } | |
538 | } | |
539 | ||
540 | /* We do not clear ssh1_host key and cookie. XXX - Okay Niels? */ | |
541 | } | |
542 | ||
51aeb639 | 543 | static void |
1853d1ef | 544 | privsep_preauth_child(void) |
545 | { | |
7fdc56c5 | 546 | u_int32_t rnd[256]; |
6ded293b | 547 | gid_t gidset[1]; |
2ea6de2b | 548 | struct passwd *pw; |
e424e241 | 549 | int i; |
1853d1ef | 550 | |
551 | /* Enable challenge-response authentication for privilege separation */ | |
552 | privsep_challenge_enable(); | |
553 | ||
554 | for (i = 0; i < 256; i++) | |
7fdc56c5 | 555 | rnd[i] = arc4random(); |
556 | RAND_seed(rnd, sizeof(rnd)); | |
1853d1ef | 557 | |
558 | /* Demote the private keys to public keys. */ | |
559 | demote_sensitive_data(); | |
560 | ||
2ea6de2b | 561 | if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) |
cdc4fc39 | 562 | fatal("Privilege separation user %s does not exist", |
563 | SSH_PRIVSEP_USER); | |
2ea6de2b | 564 | memset(pw->pw_passwd, 0, strlen(pw->pw_passwd)); |
565 | endpwent(); | |
566 | ||
343288b8 | 567 | /* Change our root directory */ |
1c352e97 | 568 | if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1) |
569 | fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR, | |
570 | strerror(errno)); | |
1853d1ef | 571 | if (chdir("/") == -1) |
edfb66cb | 572 | fatal("chdir(\"/\"): %s", strerror(errno)); |
762715ce | 573 | |
1853d1ef | 574 | /* Drop our privileges */ |
2ea6de2b | 575 | debug3("privsep user:group %u:%u", (u_int)pw->pw_uid, |
576 | (u_int)pw->pw_gid); | |
87809a1f | 577 | #if 0 |
6ff58a4b | 578 | /* XXX not ready, too heavy after chroot */ |
2ea6de2b | 579 | do_setusercontext(pw); |
87809a1f | 580 | #else |
581 | gidset[0] = pw->pw_gid; | |
87809a1f | 582 | if (setgroups(1, gidset) < 0) |
583 | fatal("setgroups: %.100s", strerror(errno)); | |
584 | permanently_set_uid(pw); | |
585 | #endif | |
1853d1ef | 586 | } |
587 | ||
2362db19 | 588 | static int |
589 | privsep_preauth(Authctxt *authctxt) | |
1853d1ef | 590 | { |
1853d1ef | 591 | int status; |
324bf712 | 592 | pid_t pid; |
1853d1ef | 593 | |
324bf712 | 594 | /* Set up unprivileged child process to deal with network data */ |
b5a28cbc | 595 | pmonitor = monitor_init(); |
324bf712 | 596 | /* Store a pointer to the kex for later rekeying */ |
b5a28cbc | 597 | pmonitor->m_pkex = &xxx_kex; |
324bf712 | 598 | |
599 | pid = fork(); | |
600 | if (pid == -1) { | |
601 | fatal("fork of unprivileged child failed"); | |
602 | } else if (pid != 0) { | |
c457707e | 603 | debug2("Network child is on pid %ld", (long)pid); |
324bf712 | 604 | |
b5a28cbc | 605 | close(pmonitor->m_recvfd); |
a9b33b95 | 606 | pmonitor->m_pid = pid; |
2362db19 | 607 | monitor_child_preauth(authctxt, pmonitor); |
b5a28cbc | 608 | close(pmonitor->m_sendfd); |
324bf712 | 609 | |
610 | /* Sync memory */ | |
b5a28cbc | 611 | monitor_sync(pmonitor); |
324bf712 | 612 | |
613 | /* Wait for the child's exit status */ | |
8c38e88b | 614 | while (waitpid(pid, &status, 0) < 0) |
615 | if (errno != EINTR) | |
616 | break; | |
2362db19 | 617 | return (1); |
324bf712 | 618 | } else { |
619 | /* child */ | |
620 | ||
b5a28cbc | 621 | close(pmonitor->m_sendfd); |
324bf712 | 622 | |
623 | /* Demote the child */ | |
624 | if (getuid() == 0 || geteuid() == 0) | |
625 | privsep_preauth_child(); | |
47c36e5b | 626 | setproctitle("%s", "[net]"); |
324bf712 | 627 | } |
2362db19 | 628 | return (0); |
324bf712 | 629 | } |
630 | ||
631 | static void | |
632 | privsep_postauth(Authctxt *authctxt) | |
633 | { | |
94d8258b | 634 | #ifdef DISABLE_FD_PASSING |
d170feb1 | 635 | if (1) { |
636 | #else | |
1853d1ef | 637 | if (authctxt->pw->pw_uid == 0 || options.use_login) { |
d170feb1 | 638 | #endif |
1853d1ef | 639 | /* File descriptor passing is broken or root login */ |
1853d1ef | 640 | use_privsep = 0; |
ae25711b | 641 | goto skip; |
1853d1ef | 642 | } |
762715ce | 643 | |
1853d1ef | 644 | /* New socket pair */ |
b5a28cbc | 645 | monitor_reinit(pmonitor); |
1853d1ef | 646 | |
b5a28cbc | 647 | pmonitor->m_pid = fork(); |
648 | if (pmonitor->m_pid == -1) | |
1853d1ef | 649 | fatal("fork of unprivileged child failed"); |
b5a28cbc | 650 | else if (pmonitor->m_pid != 0) { |
c457707e | 651 | debug2("User child is on pid %ld", (long)pmonitor->m_pid); |
b5a28cbc | 652 | close(pmonitor->m_recvfd); |
f143ed33 | 653 | buffer_clear(&loginmsg); |
b5a28cbc | 654 | monitor_child_postauth(pmonitor); |
1853d1ef | 655 | |
656 | /* NEVERREACHED */ | |
657 | exit(0); | |
658 | } | |
659 | ||
b5a28cbc | 660 | close(pmonitor->m_sendfd); |
1853d1ef | 661 | |
662 | /* Demote the private keys to public keys. */ | |
663 | demote_sensitive_data(); | |
664 | ||
665 | /* Drop privileges */ | |
666 | do_setusercontext(authctxt->pw); | |
667 | ||
ae25711b | 668 | skip: |
1853d1ef | 669 | /* It is safe now to apply the key state */ |
b5a28cbc | 670 | monitor_apply_keystate(pmonitor); |
07200973 | 671 | |
672 | /* | |
673 | * Tell the packet layer that authentication was successful, since | |
674 | * this information is not part of the key state. | |
675 | */ | |
676 | packet_set_authenticated(); | |
1853d1ef | 677 | } |
678 | ||
396c147e | 679 | static char * |
fa08c86b | 680 | list_hostkey_types(void) |
681 | { | |
3469eac4 | 682 | Buffer b; |
b6c7b7b7 | 683 | const char *p; |
684 | char *ret; | |
fa08c86b | 685 | int i; |
3469eac4 | 686 | |
687 | buffer_init(&b); | |
184eed6a | 688 | for (i = 0; i < options.num_host_key_files; i++) { |
fa08c86b | 689 | Key *key = sensitive_data.host_keys[i]; |
690 | if (key == NULL) | |
691 | continue; | |
6aacefa7 | 692 | switch (key->type) { |
fa08c86b | 693 | case KEY_RSA: |
694 | case KEY_DSA: | |
3469eac4 | 695 | if (buffer_len(&b) > 0) |
696 | buffer_append(&b, ",", 1); | |
697 | p = key_ssh_name(key); | |
698 | buffer_append(&b, p, strlen(p)); | |
fa08c86b | 699 | break; |
700 | } | |
701 | } | |
3469eac4 | 702 | buffer_append(&b, "\0", 1); |
b6c7b7b7 | 703 | ret = xstrdup(buffer_ptr(&b)); |
3469eac4 | 704 | buffer_free(&b); |
b6c7b7b7 | 705 | debug("list_hostkey_types: %s", ret); |
706 | return ret; | |
fa08c86b | 707 | } |
708 | ||
1853d1ef | 709 | Key * |
fa08c86b | 710 | get_hostkey_by_type(int type) |
711 | { | |
712 | int i; | |
e424e241 | 713 | |
184eed6a | 714 | for (i = 0; i < options.num_host_key_files; i++) { |
fa08c86b | 715 | Key *key = sensitive_data.host_keys[i]; |
716 | if (key != NULL && key->type == type) | |
717 | return key; | |
718 | } | |
719 | return NULL; | |
7368a6c8 | 720 | } |
721 | ||
1853d1ef | 722 | Key * |
723 | get_hostkey_by_index(int ind) | |
724 | { | |
725 | if (ind < 0 || ind >= options.num_host_key_files) | |
726 | return (NULL); | |
727 | return (sensitive_data.host_keys[ind]); | |
728 | } | |
729 | ||
730 | int | |
731 | get_hostkey_index(Key *key) | |
732 | { | |
733 | int i; | |
e424e241 | 734 | |
1853d1ef | 735 | for (i = 0; i < options.num_host_key_files; i++) { |
736 | if (key == sensitive_data.host_keys[i]) | |
737 | return (i); | |
738 | } | |
739 | return (-1); | |
740 | } | |
741 | ||
c345cf9d | 742 | /* |
743 | * returns 1 if connection should be dropped, 0 otherwise. | |
744 | * dropping starts at connection #max_startups_begin with a probability | |
745 | * of (max_startups_rate/100). the probability increases linearly until | |
746 | * all connections are dropped for startups > max_startups | |
747 | */ | |
396c147e | 748 | static int |
c345cf9d | 749 | drop_connection(int startups) |
750 | { | |
1c5eab6f | 751 | int p, r; |
c345cf9d | 752 | |
753 | if (startups < options.max_startups_begin) | |
754 | return 0; | |
755 | if (startups >= options.max_startups) | |
756 | return 1; | |
757 | if (options.max_startups_rate == 100) | |
758 | return 1; | |
759 | ||
760 | p = 100 - options.max_startups_rate; | |
761 | p *= startups - options.max_startups_begin; | |
1c5eab6f | 762 | p /= options.max_startups - options.max_startups_begin; |
c345cf9d | 763 | p += options.max_startups_rate; |
1c5eab6f | 764 | r = arc4random() % 100; |
c345cf9d | 765 | |
e9aec1d4 | 766 | debug("drop_connection: p %d, r %d", p, r); |
c345cf9d | 767 | return (r < p) ? 1 : 0; |
768 | } | |
769 | ||
2717fa0f | 770 | static void |
771 | usage(void) | |
772 | { | |
85ac7a84 | 773 | fprintf(stderr, "%s, %s\n", |
4526e8c2 | 774 | SSH_RELEASE, SSLeay_version(SSLEAY_VERSION)); |
65edde94 | 775 | fprintf(stderr, |
776 | "usage: sshd [-46Ddeiqt] [-b bits] [-f config_file] [-g login_grace_time]\n" | |
777 | " [-h host_key_file] [-k key_gen_time] [-o option] [-p port] [-u len]\n" | |
778 | ); | |
2717fa0f | 779 | exit(1); |
780 | } | |
781 | ||
b9a549d7 | 782 | static void |
783 | send_rexec_state(int fd, Buffer *conf) | |
784 | { | |
785 | Buffer m; | |
786 | ||
787 | debug3("%s: entering fd = %d config len %d", __func__, fd, | |
788 | buffer_len(conf)); | |
789 | ||
790 | /* | |
791 | * Protocol from reexec master to child: | |
792 | * string configuration | |
793 | * u_int ephemeral_key_follows | |
794 | * bignum e (only if ephemeral_key_follows == 1) | |
795 | * bignum n " | |
796 | * bignum d " | |
797 | * bignum iqmp " | |
798 | * bignum p " | |
799 | * bignum q " | |
72f02ae7 | 800 | * string rngseed (only if OpenSSL is not self-seeded) |
b9a549d7 | 801 | */ |
802 | buffer_init(&m); | |
803 | buffer_put_cstring(&m, buffer_ptr(conf)); | |
804 | ||
f2107e97 | 805 | if (sensitive_data.server_key != NULL && |
b9a549d7 | 806 | sensitive_data.server_key->type == KEY_RSA1) { |
807 | buffer_put_int(&m, 1); | |
808 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->e); | |
809 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->n); | |
810 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->d); | |
811 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->iqmp); | |
812 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->p); | |
813 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->q); | |
814 | } else | |
815 | buffer_put_int(&m, 0); | |
816 | ||
72f02ae7 | 817 | #ifndef OPENSSL_PRNG_ONLY |
818 | rexec_send_rng_seed(&m); | |
819 | #endif | |
820 | ||
b9a549d7 | 821 | if (ssh_msg_send(fd, 0, &m) == -1) |
822 | fatal("%s: ssh_msg_send failed", __func__); | |
823 | ||
824 | buffer_free(&m); | |
825 | ||
826 | debug3("%s: done", __func__); | |
827 | } | |
828 | ||
829 | static void | |
830 | recv_rexec_state(int fd, Buffer *conf) | |
831 | { | |
832 | Buffer m; | |
833 | char *cp; | |
834 | u_int len; | |
835 | ||
836 | debug3("%s: entering fd = %d", __func__, fd); | |
837 | ||
838 | buffer_init(&m); | |
839 | ||
840 | if (ssh_msg_recv(fd, &m) == -1) | |
841 | fatal("%s: ssh_msg_recv failed", __func__); | |
842 | if (buffer_get_char(&m) != 0) | |
843 | fatal("%s: rexec version mismatch", __func__); | |
844 | ||
845 | cp = buffer_get_string(&m, &len); | |
846 | if (conf != NULL) | |
847 | buffer_append(conf, cp, len + 1); | |
848 | xfree(cp); | |
849 | ||
850 | if (buffer_get_int(&m)) { | |
851 | if (sensitive_data.server_key != NULL) | |
852 | key_free(sensitive_data.server_key); | |
853 | sensitive_data.server_key = key_new_private(KEY_RSA1); | |
854 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->e); | |
855 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->n); | |
856 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->d); | |
857 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->iqmp); | |
858 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->p); | |
859 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->q); | |
860 | rsa_generate_additional_parameters( | |
861 | sensitive_data.server_key->rsa); | |
862 | } | |
72f02ae7 | 863 | |
864 | #ifndef OPENSSL_PRNG_ONLY | |
865 | rexec_recv_rng_seed(&m); | |
866 | #endif | |
867 | ||
b9a549d7 | 868 | buffer_free(&m); |
869 | ||
870 | debug3("%s: done", __func__); | |
871 | } | |
872 | ||
5260325f | 873 | /* |
874 | * Main program for the daemon. | |
875 | */ | |
8efc0c15 | 876 | int |
877 | main(int ac, char **av) | |
878 | { | |
5260325f | 879 | extern char *optarg; |
880 | extern int optind; | |
83529a6b | 881 | int opt, j, i, fdsetsz, on = 1; |
882 | int sock_in = -1, sock_out = -1, newsock = -1; | |
9da5c3c9 | 883 | pid_t pid; |
48e671d5 | 884 | socklen_t fromlen; |
48e671d5 | 885 | fd_set *fdset; |
886 | struct sockaddr_storage from; | |
5260325f | 887 | const char *remote_ip; |
888 | int remote_port; | |
5260325f | 889 | FILE *f; |
48e671d5 | 890 | struct addrinfo *ai; |
891 | char ntop[NI_MAXHOST], strport[NI_MAXSERV]; | |
c5894280 | 892 | char *line; |
48e671d5 | 893 | int listen_sock, maxfd; |
9216f89c | 894 | int startup_p[2] = { -1 , -1 }, config_s[2] = { -1 , -1 }; |
089fbbd2 | 895 | int startups = 0; |
aeaa3d9e | 896 | Key *key; |
2362db19 | 897 | Authctxt *authctxt; |
59c97189 | 898 | int ret, key_used = 0; |
b9a549d7 | 899 | Buffer cfg; |
5260325f | 900 | |
6e879cb4 | 901 | #ifdef HAVE_SECUREWARE |
902 | (void)set_auth_parameters(ac, av); | |
903 | #endif | |
fda04d7d | 904 | __progname = ssh_get_progname(av[0]); |
264dce47 | 905 | init_rng(); |
906 | ||
d0104542 | 907 | /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */ |
4d33e531 | 908 | saved_argc = ac; |
7706b4c7 | 909 | rexec_argc = ac; |
f420d2ba | 910 | saved_argv = xmalloc(sizeof(*saved_argv) * (ac + 1)); |
d0104542 | 911 | for (i = 0; i < ac; i++) |
912 | saved_argv[i] = xstrdup(av[i]); | |
f420d2ba | 913 | saved_argv[i] = NULL; |
d0104542 | 914 | |
915 | #ifndef HAVE_SETPROCTITLE | |
916 | /* Prepare for later setproctitle emulation */ | |
917 | compat_init_setproctitle(ac, av); | |
416c732d | 918 | av = saved_argv; |
d0104542 | 919 | #endif |
5260325f | 920 | |
a4c0faa2 | 921 | if (geteuid() == 0 && setgroups(0, NULL) == -1) |
922 | debug("setgroups(): %.200s", strerror(errno)); | |
923 | ||
fd6168c1 | 924 | /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ |
925 | sanitise_stdfd(); | |
926 | ||
5260325f | 927 | /* Initialize configuration options to their default values. */ |
928 | initialize_server_options(&options); | |
929 | ||
930 | /* Parse command-line arguments. */ | |
b9a549d7 | 931 | while ((opt = getopt(ac, av, "f:p:b:k:h:g:u:o:dDeiqrtQR46")) != -1) { |
5260325f | 932 | switch (opt) { |
48e671d5 | 933 | case '4': |
31b41ceb | 934 | options.address_family = AF_INET; |
48e671d5 | 935 | break; |
936 | case '6': | |
31b41ceb | 937 | options.address_family = AF_INET6; |
48e671d5 | 938 | break; |
5260325f | 939 | case 'f': |
940 | config_file_name = optarg; | |
941 | break; | |
942 | case 'd': | |
e053cd2c | 943 | if (debug_flag == 0) { |
bcbf86ec | 944 | debug_flag = 1; |
945 | options.log_level = SYSLOG_LEVEL_DEBUG1; | |
e053cd2c | 946 | } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) |
bcbf86ec | 947 | options.log_level++; |
5260325f | 948 | break; |
0b6fbf03 | 949 | case 'D': |
950 | no_daemon_flag = 1; | |
951 | break; | |
ff14faf1 | 952 | case 'e': |
953 | log_stderr = 1; | |
954 | break; | |
5260325f | 955 | case 'i': |
956 | inetd_flag = 1; | |
957 | break; | |
b9a549d7 | 958 | case 'r': |
959 | rexec_flag = 0; | |
960 | break; | |
961 | case 'R': | |
962 | rexeced_flag = 1; | |
963 | inetd_flag = 1; | |
964 | break; | |
5260325f | 965 | case 'Q': |
9bd5b720 | 966 | /* ignored */ |
5260325f | 967 | break; |
968 | case 'q': | |
969 | options.log_level = SYSLOG_LEVEL_QUIET; | |
970 | break; | |
971 | case 'b': | |
972 | options.server_key_bits = atoi(optarg); | |
973 | break; | |
974 | case 'p': | |
48e671d5 | 975 | options.ports_from_cmdline = 1; |
bcbf86ec | 976 | if (options.num_ports >= MAX_PORTS) { |
977 | fprintf(stderr, "too many ports.\n"); | |
978 | exit(1); | |
979 | } | |
2d2a2c65 | 980 | options.ports[options.num_ports++] = a2port(optarg); |
981 | if (options.ports[options.num_ports-1] == 0) { | |
982 | fprintf(stderr, "Bad port number.\n"); | |
983 | exit(1); | |
984 | } | |
5260325f | 985 | break; |
986 | case 'g': | |
e2b1fb42 | 987 | if ((options.login_grace_time = convtime(optarg)) == -1) { |
988 | fprintf(stderr, "Invalid login grace time.\n"); | |
989 | exit(1); | |
990 | } | |
5260325f | 991 | break; |
992 | case 'k': | |
e2b1fb42 | 993 | if ((options.key_regeneration_time = convtime(optarg)) == -1) { |
994 | fprintf(stderr, "Invalid key regeneration interval.\n"); | |
995 | exit(1); | |
996 | } | |
5260325f | 997 | break; |
998 | case 'h': | |
fa08c86b | 999 | if (options.num_host_key_files >= MAX_HOSTKEYS) { |
1000 | fprintf(stderr, "too many host keys.\n"); | |
1001 | exit(1); | |
1002 | } | |
1003 | options.host_key_files[options.num_host_key_files++] = optarg; | |
5260325f | 1004 | break; |
f87f09aa | 1005 | case 't': |
1006 | test_flag = 1; | |
1007 | break; | |
c345cf9d | 1008 | case 'u': |
1009 | utmp_len = atoi(optarg); | |
67f04db1 | 1010 | if (utmp_len > MAXHOSTNAMELEN) { |
1011 | fprintf(stderr, "Invalid utmp length.\n"); | |
1012 | exit(1); | |
1013 | } | |
c345cf9d | 1014 | break; |
2717fa0f | 1015 | case 'o': |
c5894280 | 1016 | line = xstrdup(optarg); |
1017 | if (process_server_config_line(&options, line, | |
2717fa0f | 1018 | "command-line", 0) != 0) |
184eed6a | 1019 | exit(1); |
c5894280 | 1020 | xfree(line); |
2717fa0f | 1021 | break; |
5260325f | 1022 | case '?': |
1023 | default: | |
2717fa0f | 1024 | usage(); |
1025 | break; | |
5260325f | 1026 | } |
1027 | } | |
b9a549d7 | 1028 | if (rexeced_flag || inetd_flag) |
1029 | rexec_flag = 0; | |
1030 | if (rexec_flag && (av[0] == NULL || *av[0] != '/')) | |
1031 | fatal("sshd re-exec requires execution with an absolute path"); | |
1032 | if (rexeced_flag) | |
b250e837 | 1033 | closefrom(REEXEC_MIN_FREE_FD); |
1034 | else | |
1035 | closefrom(REEXEC_DEVCRYPTO_RESERVED_FD); | |
b9a549d7 | 1036 | |
1a92bd7e | 1037 | SSLeay_add_all_algorithms(); |
5260325f | 1038 | |
48e671d5 | 1039 | /* |
1040 | * Force logging to stderr until we have loaded the private host | |
1041 | * key (unless started from inetd) | |
1042 | */ | |
1fe6a48f | 1043 | log_init(__progname, |
980c9344 | 1044 | options.log_level == SYSLOG_LEVEL_NOT_SET ? |
1045 | SYSLOG_LEVEL_INFO : options.log_level, | |
1046 | options.log_facility == SYSLOG_FACILITY_NOT_SET ? | |
1047 | SYSLOG_FACILITY_AUTH : options.log_facility, | |
51efad8c | 1048 | log_stderr || !inetd_flag); |
48e671d5 | 1049 | |
351f44a0 | 1050 | /* |
1051 | * Unset KRB5CCNAME, otherwise the user's session may inherit it from | |
1052 | * root's environment | |
d1cf9a87 | 1053 | */ |
3bfd27d5 | 1054 | if (getenv("KRB5CCNAME") != NULL) |
1055 | unsetenv("KRB5CCNAME"); | |
1056 | ||
ef51930f | 1057 | #ifdef _UNICOS |
e5ba4718 | 1058 | /* Cray can define user privs drop all privs now! |
1a23ac2c | 1059 | * Not needed on PRIV_SU systems! |
1060 | */ | |
1061 | drop_cray_privs(); | |
1062 | #endif | |
1063 | ||
b9a549d7 | 1064 | sensitive_data.server_key = NULL; |
1065 | sensitive_data.ssh1_host_key = NULL; | |
1066 | sensitive_data.have_ssh1_key = 0; | |
1067 | sensitive_data.have_ssh2_key = 0; | |
1068 | ||
1069 | /* Fetch our configuration */ | |
1070 | buffer_init(&cfg); | |
1071 | if (rexeced_flag) | |
b250e837 | 1072 | recv_rexec_state(REEXEC_CONFIG_PASS_FD, &cfg); |
b9a549d7 | 1073 | else |
1074 | load_server_config(config_file_name, &cfg); | |
1075 | ||
1076 | parse_server_config(&options, | |
1077 | rexeced_flag ? "rexec" : config_file_name, &cfg); | |
1078 | ||
1079 | if (!rexec_flag) | |
1080 | buffer_free(&cfg); | |
5260325f | 1081 | |
72f02ae7 | 1082 | seed_rng(); |
1083 | ||
5260325f | 1084 | /* Fill in default values for those options not explicitly set. */ |
1085 | fill_default_server_options(&options); | |
1086 | ||
31b41ceb | 1087 | /* set default channel AF */ |
1088 | channel_set_af(options.address_family); | |
1089 | ||
5260325f | 1090 | /* Check that there are no remaining arguments. */ |
1091 | if (optind < ac) { | |
1092 | fprintf(stderr, "Extra argument %s.\n", av[optind]); | |
1093 | exit(1); | |
8efc0c15 | 1094 | } |
5260325f | 1095 | |
4526e8c2 | 1096 | debug("sshd version %.100s", SSH_RELEASE); |
5260325f | 1097 | |
fa08c86b | 1098 | /* load private host keys */ |
343288b8 | 1099 | sensitive_data.host_keys = xmalloc(options.num_host_key_files * |
1100 | sizeof(Key *)); | |
184eed6a | 1101 | for (i = 0; i < options.num_host_key_files; i++) |
1e3b8b07 | 1102 | sensitive_data.host_keys[i] = NULL; |
a306f2dd | 1103 | |
184eed6a | 1104 | for (i = 0; i < options.num_host_key_files; i++) { |
aeaa3d9e | 1105 | key = key_load_private(options.host_key_files[i], "", NULL); |
1106 | sensitive_data.host_keys[i] = key; | |
fa08c86b | 1107 | if (key == NULL) { |
58cfa257 | 1108 | error("Could not load host key: %s", |
1109 | options.host_key_files[i]); | |
aeaa3d9e | 1110 | sensitive_data.host_keys[i] = NULL; |
fa08c86b | 1111 | continue; |
a306f2dd | 1112 | } |
6aacefa7 | 1113 | switch (key->type) { |
fa08c86b | 1114 | case KEY_RSA1: |
1115 | sensitive_data.ssh1_host_key = key; | |
1116 | sensitive_data.have_ssh1_key = 1; | |
1117 | break; | |
1118 | case KEY_RSA: | |
1119 | case KEY_DSA: | |
1120 | sensitive_data.have_ssh2_key = 1; | |
1121 | break; | |
a306f2dd | 1122 | } |
aeaa3d9e | 1123 | debug("private host key: #%d type %d %s", i, key->type, |
1124 | key_type(key)); | |
fa08c86b | 1125 | } |
1126 | if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) { | |
bbe88b6d | 1127 | logit("Disabling protocol version 1. Could not load host key"); |
fa08c86b | 1128 | options.protocol &= ~SSH_PROTO_1; |
1129 | } | |
1130 | if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) { | |
bbe88b6d | 1131 | logit("Disabling protocol version 2. Could not load host key"); |
fa08c86b | 1132 | options.protocol &= ~SSH_PROTO_2; |
a306f2dd | 1133 | } |
6a416424 | 1134 | if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) { |
bbe88b6d | 1135 | logit("sshd: no hostkeys available -- exiting."); |
5260325f | 1136 | exit(1); |
1137 | } | |
5260325f | 1138 | |
a306f2dd | 1139 | /* Check certain values for sanity. */ |
1140 | if (options.protocol & SSH_PROTO_1) { | |
1141 | if (options.server_key_bits < 512 || | |
1142 | options.server_key_bits > 32768) { | |
1143 | fprintf(stderr, "Bad server key size.\n"); | |
1144 | exit(1); | |
1145 | } | |
1146 | /* | |
1147 | * Check that server and host key lengths differ sufficiently. This | |
1148 | * is necessary to make double encryption work with rsaref. Oh, I | |
1149 | * hate software patents. I dont know if this can go? Niels | |
1150 | */ | |
1151 | if (options.server_key_bits > | |
e424e241 | 1152 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) - |
1153 | SSH_KEY_BITS_RESERVED && options.server_key_bits < | |
1154 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + | |
1155 | SSH_KEY_BITS_RESERVED) { | |
a306f2dd | 1156 | options.server_key_bits = |
e424e241 | 1157 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + |
1158 | SSH_KEY_BITS_RESERVED; | |
a306f2dd | 1159 | debug("Forcing server key to %d bits to make it differ from host key.", |
1160 | options.server_key_bits); | |
1161 | } | |
1162 | } | |
1163 | ||
3cc54fbb | 1164 | if (use_privsep) { |
1165 | struct passwd *pw; | |
1166 | struct stat st; | |
1167 | ||
1168 | if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) | |
1169 | fatal("Privilege separation user %s does not exist", | |
1170 | SSH_PRIVSEP_USER); | |
1171 | if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) || | |
1172 | (S_ISDIR(st.st_mode) == 0)) | |
1173 | fatal("Missing privilege separation directory: %s", | |
1174 | _PATH_PRIVSEP_CHROOT_DIR); | |
b9b82dab | 1175 | |
1176 | #ifdef HAVE_CYGWIN | |
1177 | if (check_ntsec(_PATH_PRIVSEP_CHROOT_DIR) && | |
1178 | (st.st_uid != getuid () || | |
1179 | (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)) | |
1180 | #else | |
a56313d7 | 1181 | if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0) |
b9b82dab | 1182 | #endif |
5f021474 | 1183 | fatal("%s must be owned by root and not group or " |
1184 | "world-writable.", _PATH_PRIVSEP_CHROOT_DIR); | |
3cc54fbb | 1185 | } |
1186 | ||
f87f09aa | 1187 | /* Configuration looks good, so exit if in test mode. */ |
1188 | if (test_flag) | |
1189 | exit(0); | |
1190 | ||
018a5ea3 | 1191 | /* |
1192 | * Clear out any supplemental groups we may have inherited. This | |
1193 | * prevents inadvertent creation of files with bad modes (in the | |
aff51935 | 1194 | * portable version at least, it's certainly possible for PAM |
1195 | * to create a file, and we can't control the code in every | |
018a5ea3 | 1196 | * module which might be used). |
1197 | */ | |
1198 | if (setgroups(0, NULL) < 0) | |
1199 | debug("setgroups() failed: %.200s", strerror(errno)); | |
1200 | ||
b9a549d7 | 1201 | if (rexec_flag) { |
1202 | rexec_argv = xmalloc(sizeof(char *) * (rexec_argc + 2)); | |
1203 | for (i = 0; i < rexec_argc; i++) { | |
1204 | debug("rexec_argv[%d]='%s'", i, saved_argv[i]); | |
1205 | rexec_argv[i] = saved_argv[i]; | |
1206 | } | |
1207 | rexec_argv[rexec_argc] = "-R"; | |
1208 | rexec_argv[rexec_argc + 1] = NULL; | |
1209 | } | |
1210 | ||
a306f2dd | 1211 | /* Initialize the log (it is reinitialized below in case we forked). */ |
25c31d49 | 1212 | if (debug_flag && (!inetd_flag || rexeced_flag)) |
5260325f | 1213 | log_stderr = 1; |
1fe6a48f | 1214 | log_init(__progname, options.log_level, options.log_facility, log_stderr); |
5260325f | 1215 | |
a306f2dd | 1216 | /* |
1217 | * If not in debugging mode, and not started from inetd, disconnect | |
1218 | * from the controlling terminal, and fork. The original process | |
1219 | * exits. | |
1220 | */ | |
0b6fbf03 | 1221 | if (!(debug_flag || inetd_flag || no_daemon_flag)) { |
8efc0c15 | 1222 | #ifdef TIOCNOTTY |
5260325f | 1223 | int fd; |
8efc0c15 | 1224 | #endif /* TIOCNOTTY */ |
5260325f | 1225 | if (daemon(0, 0) < 0) |
1226 | fatal("daemon() failed: %.200s", strerror(errno)); | |
1227 | ||
1228 | /* Disconnect from the controlling tty. */ | |
8efc0c15 | 1229 | #ifdef TIOCNOTTY |
5ca51e19 | 1230 | fd = open(_PATH_TTY, O_RDWR | O_NOCTTY); |
5260325f | 1231 | if (fd >= 0) { |
1232 | (void) ioctl(fd, TIOCNOTTY, NULL); | |
1233 | close(fd); | |
1234 | } | |
8efc0c15 | 1235 | #endif /* TIOCNOTTY */ |
8efc0c15 | 1236 | } |
5260325f | 1237 | /* Reinitialize the log (because of the fork above). */ |
1fe6a48f | 1238 | log_init(__progname, options.log_level, options.log_facility, log_stderr); |
5260325f | 1239 | |
5260325f | 1240 | /* Initialize the random number generator. */ |
1241 | arc4random_stir(); | |
1242 | ||
1243 | /* Chdir to the root directory so that the current disk can be | |
1244 | unmounted if desired. */ | |
1245 | chdir("/"); | |
184eed6a | 1246 | |
1d3c30db | 1247 | /* ignore SIGPIPE */ |
1248 | signal(SIGPIPE, SIG_IGN); | |
5260325f | 1249 | |
5260325f | 1250 | /* Start listening for a socket, unless started from inetd. */ |
1251 | if (inetd_flag) { | |
b9a549d7 | 1252 | int fd; |
1253 | ||
4c8722d9 | 1254 | startup_pipe = -1; |
b9a549d7 | 1255 | if (rexeced_flag) { |
b250e837 | 1256 | close(REEXEC_CONFIG_PASS_FD); |
b9a549d7 | 1257 | sock_in = sock_out = dup(STDIN_FILENO); |
1258 | if (!debug_flag) { | |
b250e837 | 1259 | startup_pipe = dup(REEXEC_STARTUP_PIPE_FD); |
1260 | close(REEXEC_STARTUP_PIPE_FD); | |
b9a549d7 | 1261 | } |
1262 | } else { | |
1263 | sock_in = dup(STDIN_FILENO); | |
1264 | sock_out = dup(STDOUT_FILENO); | |
1265 | } | |
a306f2dd | 1266 | /* |
1267 | * We intentionally do not close the descriptors 0, 1, and 2 | |
b9a549d7 | 1268 | * as our code for setting the descriptors won't work if |
a306f2dd | 1269 | * ttyfd happens to be one of those. |
1270 | */ | |
b9a549d7 | 1271 | if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { |
1272 | dup2(fd, STDIN_FILENO); | |
1273 | dup2(fd, STDOUT_FILENO); | |
1274 | if (fd > STDOUT_FILENO) | |
1275 | close(fd); | |
1276 | } | |
5260325f | 1277 | debug("inetd sockets after dupping: %d, %d", sock_in, sock_out); |
b9a549d7 | 1278 | if ((options.protocol & SSH_PROTO_1) && |
1279 | sensitive_data.server_key == NULL) | |
cb7bd922 | 1280 | generate_ephemeral_server_key(); |
5260325f | 1281 | } else { |
48e671d5 | 1282 | for (ai = options.listen_addrs; ai; ai = ai->ai_next) { |
1283 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) | |
1284 | continue; | |
1285 | if (num_listen_socks >= MAX_LISTEN_SOCKS) | |
1286 | fatal("Too many listen sockets. " | |
1287 | "Enlarge MAX_LISTEN_SOCKS"); | |
945a9853 | 1288 | if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen, |
48e671d5 | 1289 | ntop, sizeof(ntop), strport, sizeof(strport), |
945a9853 | 1290 | NI_NUMERICHOST|NI_NUMERICSERV)) != 0) { |
1291 | error("getnameinfo failed: %.100s", | |
1292 | (ret != EAI_SYSTEM) ? gai_strerror(ret) : | |
1293 | strerror(errno)); | |
48e671d5 | 1294 | continue; |
1295 | } | |
1296 | /* Create socket for listening. */ | |
3e131a6d | 1297 | listen_sock = socket(ai->ai_family, ai->ai_socktype, |
1298 | ai->ai_protocol); | |
48e671d5 | 1299 | if (listen_sock < 0) { |
1300 | /* kernel may not support ipv6 */ | |
1301 | verbose("socket: %.100s", strerror(errno)); | |
1302 | continue; | |
1303 | } | |
170694d7 | 1304 | if (set_nonblock(listen_sock) == -1) { |
a666e3b1 | 1305 | close(listen_sock); |
1306 | continue; | |
1307 | } | |
48e671d5 | 1308 | /* |
facfd613 | 1309 | * Set socket options. |
1310 | * Allow local port reuse in TIME_WAIT. | |
48e671d5 | 1311 | */ |
facfd613 | 1312 | if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR, |
1313 | &on, sizeof(on)) == -1) | |
1314 | error("setsockopt SO_REUSEADDR: %s", strerror(errno)); | |
48e671d5 | 1315 | |
1316 | debug("Bind to port %s on %s.", strport, ntop); | |
1317 | ||
1318 | /* Bind the socket to the desired port. */ | |
32ced054 | 1319 | if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) { |
1320 | if (!ai->ai_next) | |
1321 | error("Bind to port %s on %s failed: %.200s.", | |
1322 | strport, ntop, strerror(errno)); | |
48e671d5 | 1323 | close(listen_sock); |
1324 | continue; | |
1325 | } | |
1326 | listen_socks[num_listen_socks] = listen_sock; | |
1327 | num_listen_socks++; | |
1328 | ||
1329 | /* Start listening on the port. */ | |
bbe88b6d | 1330 | logit("Server listening on %s port %s.", ntop, strport); |
fce39749 | 1331 | if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0) |
48e671d5 | 1332 | fatal("listen: %.100s", strerror(errno)); |
1333 | ||
5260325f | 1334 | } |
48e671d5 | 1335 | freeaddrinfo(options.listen_addrs); |
1336 | ||
1337 | if (!num_listen_socks) | |
1338 | fatal("Cannot bind any address."); | |
1339 | ||
3aca00a3 | 1340 | if (options.protocol & SSH_PROTO_1) |
1341 | generate_ephemeral_server_key(); | |
1342 | ||
1343 | /* | |
1344 | * Arrange to restart on SIGHUP. The handler needs | |
1345 | * listen_sock. | |
1346 | */ | |
1347 | signal(SIGHUP, sighup_handler); | |
1348 | ||
1349 | signal(SIGTERM, sigterm_handler); | |
1350 | signal(SIGQUIT, sigterm_handler); | |
1351 | ||
1352 | /* Arrange SIGCHLD to be caught. */ | |
1353 | signal(SIGCHLD, main_sigchld_handler); | |
1354 | ||
1355 | /* Write out the pid file after the sigterm handler is setup */ | |
5260325f | 1356 | if (!debug_flag) { |
aa3378df | 1357 | /* |
97fb6912 | 1358 | * Record our pid in /var/run/sshd.pid to make it |
1359 | * easier to kill the correct sshd. We don't want to | |
1360 | * do this before the bind above because the bind will | |
aa3378df | 1361 | * fail if there already is a daemon, and this will |
1362 | * overwrite any old pid in the file. | |
1363 | */ | |
3c62e7eb | 1364 | f = fopen(options.pid_file, "wb"); |
71b9ced0 | 1365 | if (f == NULL) { |
1366 | error("Couldn't create pid file \"%s\": %s", | |
1367 | options.pid_file, strerror(errno)); | |
1368 | } else { | |
c457707e | 1369 | fprintf(f, "%ld\n", (long) getpid()); |
5260325f | 1370 | fclose(f); |
1371 | } | |
8efc0c15 | 1372 | } |
5260325f | 1373 | |
48e671d5 | 1374 | /* setup fd set for listen */ |
089fbbd2 | 1375 | fdset = NULL; |
48e671d5 | 1376 | maxfd = 0; |
1377 | for (i = 0; i < num_listen_socks; i++) | |
1378 | if (listen_socks[i] > maxfd) | |
1379 | maxfd = listen_socks[i]; | |
089fbbd2 | 1380 | /* pipes connected to unauthenticated childs */ |
1381 | startup_pipes = xmalloc(options.max_startups * sizeof(int)); | |
1382 | for (i = 0; i < options.max_startups; i++) | |
1383 | startup_pipes[i] = -1; | |
48e671d5 | 1384 | |
aa3378df | 1385 | /* |
1386 | * Stay listening for connections until the system crashes or | |
1387 | * the daemon is killed with a signal. | |
1388 | */ | |
5260325f | 1389 | for (;;) { |
1390 | if (received_sighup) | |
1391 | sighup_restart(); | |
089fbbd2 | 1392 | if (fdset != NULL) |
1393 | xfree(fdset); | |
b5c334cc | 1394 | fdsetsz = howmany(maxfd+1, NFDBITS) * sizeof(fd_mask); |
089fbbd2 | 1395 | fdset = (fd_set *)xmalloc(fdsetsz); |
48e671d5 | 1396 | memset(fdset, 0, fdsetsz); |
089fbbd2 | 1397 | |
48e671d5 | 1398 | for (i = 0; i < num_listen_socks; i++) |
1399 | FD_SET(listen_socks[i], fdset); | |
089fbbd2 | 1400 | for (i = 0; i < options.max_startups; i++) |
1401 | if (startup_pipes[i] != -1) | |
1402 | FD_SET(startup_pipes[i], fdset); | |
1403 | ||
1404 | /* Wait in select until there is a connection. */ | |
59c97189 | 1405 | ret = select(maxfd+1, fdset, NULL, NULL, NULL); |
1406 | if (ret < 0 && errno != EINTR) | |
1407 | error("select: %.100s", strerror(errno)); | |
c9130033 | 1408 | if (received_sigterm) { |
bbe88b6d | 1409 | logit("Received signal %d; terminating.", |
010f9726 | 1410 | (int) received_sigterm); |
c9130033 | 1411 | close_listen_socks(); |
1412 | unlink(options.pid_file); | |
1413 | exit(255); | |
1414 | } | |
59c97189 | 1415 | if (key_used && key_do_regen) { |
cb7bd922 | 1416 | generate_ephemeral_server_key(); |
59c97189 | 1417 | key_used = 0; |
1418 | key_do_regen = 0; | |
48e671d5 | 1419 | } |
59c97189 | 1420 | if (ret < 0) |
1421 | continue; | |
1422 | ||
089fbbd2 | 1423 | for (i = 0; i < options.max_startups; i++) |
1424 | if (startup_pipes[i] != -1 && | |
1425 | FD_ISSET(startup_pipes[i], fdset)) { | |
1426 | /* | |
1427 | * the read end of the pipe is ready | |
1428 | * if the child has closed the pipe | |
8abcdba4 | 1429 | * after successful authentication |
089fbbd2 | 1430 | * or if the child has died |
1431 | */ | |
1432 | close(startup_pipes[i]); | |
1433 | startup_pipes[i] = -1; | |
1434 | startups--; | |
1435 | } | |
48e671d5 | 1436 | for (i = 0; i < num_listen_socks; i++) { |
1437 | if (!FD_ISSET(listen_socks[i], fdset)) | |
5260325f | 1438 | continue; |
089fbbd2 | 1439 | fromlen = sizeof(from); |
1440 | newsock = accept(listen_socks[i], (struct sockaddr *)&from, | |
1441 | &fromlen); | |
1442 | if (newsock < 0) { | |
1443 | if (errno != EINTR && errno != EWOULDBLOCK) | |
1444 | error("accept: %.100s", strerror(errno)); | |
1445 | continue; | |
1446 | } | |
170694d7 | 1447 | if (unset_nonblock(newsock) == -1) { |
a666e3b1 | 1448 | close(newsock); |
1449 | continue; | |
1450 | } | |
c345cf9d | 1451 | if (drop_connection(startups) == 1) { |
1452 | debug("drop connection #%d", startups); | |
089fbbd2 | 1453 | close(newsock); |
1454 | continue; | |
1455 | } | |
1456 | if (pipe(startup_p) == -1) { | |
1457 | close(newsock); | |
1458 | continue; | |
1459 | } | |
1460 | ||
b9a549d7 | 1461 | if (rexec_flag && socketpair(AF_UNIX, |
1462 | SOCK_STREAM, 0, config_s) == -1) { | |
1463 | error("reexec socketpair: %s", | |
1464 | strerror(errno)); | |
1465 | close(newsock); | |
1466 | close(startup_p[0]); | |
1467 | close(startup_p[1]); | |
1468 | continue; | |
1469 | } | |
1470 | ||
089fbbd2 | 1471 | for (j = 0; j < options.max_startups; j++) |
1472 | if (startup_pipes[j] == -1) { | |
1473 | startup_pipes[j] = startup_p[0]; | |
1474 | if (maxfd < startup_p[0]) | |
1475 | maxfd = startup_p[0]; | |
1476 | startups++; | |
1477 | break; | |
1478 | } | |
2b87da3b | 1479 | |
aa3378df | 1480 | /* |
089fbbd2 | 1481 | * Got connection. Fork a child to handle it, unless |
1482 | * we are in debugging mode. | |
aa3378df | 1483 | */ |
089fbbd2 | 1484 | if (debug_flag) { |
aa3378df | 1485 | /* |
089fbbd2 | 1486 | * In debugging mode. Close the listening |
1487 | * socket, and start processing the | |
1488 | * connection without forking. | |
aa3378df | 1489 | */ |
089fbbd2 | 1490 | debug("Server will not fork when running in debugging mode."); |
48e671d5 | 1491 | close_listen_socks(); |
5260325f | 1492 | sock_in = newsock; |
1493 | sock_out = newsock; | |
b9a549d7 | 1494 | close(startup_p[0]); |
1495 | close(startup_p[1]); | |
5540ea9b | 1496 | startup_pipe = -1; |
3f7a7e4a | 1497 | pid = getpid(); |
b9a549d7 | 1498 | if (rexec_flag) { |
1499 | send_rexec_state(config_s[0], | |
1500 | &cfg); | |
1501 | close(config_s[0]); | |
1502 | } | |
5260325f | 1503 | break; |
089fbbd2 | 1504 | } else { |
1505 | /* | |
1506 | * Normal production daemon. Fork, and have | |
1507 | * the child process the connection. The | |
1508 | * parent continues listening. | |
1509 | */ | |
1510 | if ((pid = fork()) == 0) { | |
1511 | /* | |
1512 | * Child. Close the listening and max_startup | |
1513 | * sockets. Start using the accepted socket. | |
1514 | * Reinitialize logging (since our pid has | |
1515 | * changed). We break out of the loop to handle | |
1516 | * the connection. | |
1517 | */ | |
1518 | startup_pipe = startup_p[1]; | |
7ace8c3b | 1519 | close_startup_pipes(); |
089fbbd2 | 1520 | close_listen_socks(); |
1521 | sock_in = newsock; | |
1522 | sock_out = newsock; | |
1fe6a48f | 1523 | log_init(__progname, options.log_level, options.log_facility, log_stderr); |
9216f89c | 1524 | if (rexec_flag) |
1525 | close(config_s[0]); | |
089fbbd2 | 1526 | break; |
1527 | } | |
5260325f | 1528 | } |
5260325f | 1529 | |
089fbbd2 | 1530 | /* Parent. Stay in the loop. */ |
1531 | if (pid < 0) | |
1532 | error("fork: %.100s", strerror(errno)); | |
1533 | else | |
c457707e | 1534 | debug("Forked child %ld.", (long)pid); |
5260325f | 1535 | |
089fbbd2 | 1536 | close(startup_p[1]); |
5260325f | 1537 | |
b9a549d7 | 1538 | if (rexec_flag) { |
1539 | send_rexec_state(config_s[0], &cfg); | |
1540 | close(config_s[0]); | |
1541 | close(config_s[1]); | |
1542 | } | |
1543 | ||
089fbbd2 | 1544 | /* Mark that the key has been used (it was "given" to the child). */ |
59c97189 | 1545 | if ((options.protocol & SSH_PROTO_1) && |
1546 | key_used == 0) { | |
1547 | /* Schedule server key regeneration alarm. */ | |
f00d1f78 | 1548 | signal(SIGALRM, key_regeneration_alarm); |
59c97189 | 1549 | alarm(options.key_regeneration_time); |
1550 | key_used = 1; | |
1551 | } | |
5260325f | 1552 | |
089fbbd2 | 1553 | arc4random_stir(); |
1554 | ||
1555 | /* Close the new socket (the child is now taking care of it). */ | |
1556 | close(newsock); | |
1557 | } | |
48e671d5 | 1558 | /* child process check (or debug mode) */ |
1559 | if (num_listen_socks < 0) | |
1560 | break; | |
5260325f | 1561 | } |
1562 | } | |
8efc0c15 | 1563 | |
5260325f | 1564 | /* This is the child processing a new connection. */ |
cc120685 | 1565 | setproctitle("%s", "[accepted]"); |
5260325f | 1566 | |
8b758bd2 | 1567 | /* |
1568 | * Create a new session and process group since the 4.4BSD | |
1569 | * setlogin() affects the entire process group. We don't | |
1570 | * want the child to be able to affect the parent. | |
1571 | */ | |
1572 | #if !defined(SSHD_ACQUIRES_CTTY) | |
1573 | /* | |
1574 | * If setsid is called, on some platforms sshd will later acquire a | |
1575 | * controlling terminal which will result in "could not set | |
1576 | * controlling tty" errors. | |
1577 | */ | |
1578 | if (!debug_flag && !inetd_flag && setsid() < 0) | |
1579 | error("setsid: %.100s", strerror(errno)); | |
1580 | #endif | |
1581 | ||
b9a549d7 | 1582 | if (rexec_flag) { |
1583 | int fd; | |
1584 | ||
b250e837 | 1585 | debug("rexec start in %d out %d newsock %d pipe %d sock %d", |
1586 | sock_in, sock_out, newsock, startup_pipe, config_s[0]); | |
b9a549d7 | 1587 | dup2(newsock, STDIN_FILENO); |
1588 | dup2(STDIN_FILENO, STDOUT_FILENO); | |
1589 | if (startup_pipe == -1) | |
b250e837 | 1590 | close(REEXEC_STARTUP_PIPE_FD); |
b9a549d7 | 1591 | else |
b250e837 | 1592 | dup2(startup_pipe, REEXEC_STARTUP_PIPE_FD); |
b9a549d7 | 1593 | |
b250e837 | 1594 | dup2(config_s[1], REEXEC_CONFIG_PASS_FD); |
b9a549d7 | 1595 | close(config_s[1]); |
ad148c04 | 1596 | if (startup_pipe != -1) |
1597 | close(startup_pipe); | |
b250e837 | 1598 | |
b9a549d7 | 1599 | execv(rexec_argv[0], rexec_argv); |
1600 | ||
1601 | /* Reexec has failed, fall back and continue */ | |
1602 | error("rexec of %s failed: %s", rexec_argv[0], strerror(errno)); | |
b250e837 | 1603 | recv_rexec_state(REEXEC_CONFIG_PASS_FD, NULL); |
b9a549d7 | 1604 | log_init(__progname, options.log_level, |
1605 | options.log_facility, log_stderr); | |
1606 | ||
1607 | /* Clean up fds */ | |
b250e837 | 1608 | startup_pipe = REEXEC_STARTUP_PIPE_FD; |
b9a549d7 | 1609 | close(config_s[1]); |
b250e837 | 1610 | close(REEXEC_CONFIG_PASS_FD); |
1611 | newsock = sock_out = sock_in = dup(STDIN_FILENO); | |
b9a549d7 | 1612 | if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { |
1613 | dup2(fd, STDIN_FILENO); | |
1614 | dup2(fd, STDOUT_FILENO); | |
1615 | if (fd > STDERR_FILENO) | |
1616 | close(fd); | |
1617 | } | |
b250e837 | 1618 | debug("rexec cleanup in %d out %d newsock %d pipe %d sock %d", |
1619 | sock_in, sock_out, newsock, startup_pipe, config_s[0]); | |
b9a549d7 | 1620 | } |
1621 | ||
aa3378df | 1622 | /* |
1623 | * Disable the key regeneration alarm. We will not regenerate the | |
1624 | * key since we are no longer in a position to give it to anyone. We | |
1625 | * will not restart on SIGHUP since it no longer makes sense. | |
1626 | */ | |
5260325f | 1627 | alarm(0); |
1628 | signal(SIGALRM, SIG_DFL); | |
1629 | signal(SIGHUP, SIG_DFL); | |
1630 | signal(SIGTERM, SIG_DFL); | |
1631 | signal(SIGQUIT, SIG_DFL); | |
1632 | signal(SIGCHLD, SIG_DFL); | |
9aaf9be4 | 1633 | signal(SIGINT, SIG_DFL); |
5260325f | 1634 | |
aa3378df | 1635 | /* |
1636 | * Register our connection. This turns encryption off because we do | |
1637 | * not have a key. | |
1638 | */ | |
5260325f | 1639 | packet_set_connection(sock_in, sock_out); |
07200973 | 1640 | packet_set_server(); |
5260325f | 1641 | |
7c3bc5a2 | 1642 | /* Set SO_KEEPALIVE if requested. */ |
1643 | if (options.tcp_keep_alive && packet_connection_is_on_socket() && | |
1644 | setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) < 0) | |
1645 | error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); | |
1646 | ||
29798ed0 | 1647 | if ((remote_port = get_remote_port()) < 0) { |
1648 | debug("get_remote_port failed"); | |
1649 | cleanup_exit(255); | |
1650 | } | |
3a85986d | 1651 | |
1652 | /* | |
1653 | * We use get_canonical_hostname with usedns = 0 instead of | |
1654 | * get_remote_ipaddr here so IP options will be checked. | |
1655 | */ | |
1656 | remote_ip = get_canonical_hostname(0); | |
5260325f | 1657 | |
6039eeef | 1658 | #ifdef SSH_AUDIT_EVENTS |
c00e4d75 | 1659 | audit_connection_from(remote_ip, remote_port); |
1660 | #endif | |
5260325f | 1661 | #ifdef LIBWRAP |
ac28afd8 | 1662 | /* Check whether logins are denied from this host. */ |
33e5359c | 1663 | if (packet_connection_is_on_socket()) { |
5260325f | 1664 | struct request_info req; |
8efc0c15 | 1665 | |
8fbc356d | 1666 | request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0); |
5260325f | 1667 | fromhost(&req); |
8efc0c15 | 1668 | |
5260325f | 1669 | if (!hosts_access(&req)) { |
ac28afd8 | 1670 | debug("Connection refused by tcp wrapper"); |
563834bb | 1671 | refuse(&req); |
ac28afd8 | 1672 | /* NOTREACHED */ |
1673 | fatal("libwrap refuse returns"); | |
5260325f | 1674 | } |
8efc0c15 | 1675 | } |
48e671d5 | 1676 | #endif /* LIBWRAP */ |
ac28afd8 | 1677 | |
5260325f | 1678 | /* Log the connection. */ |
1679 | verbose("Connection from %.500s port %d", remote_ip, remote_port); | |
8efc0c15 | 1680 | |
aa3378df | 1681 | /* |
7b9b0103 | 1682 | * We don't want to listen forever unless the other side |
aa3378df | 1683 | * successfully authenticates itself. So we set up an alarm which is |
1684 | * cleared after successful authentication. A limit of zero | |
7b9b0103 | 1685 | * indicates no limit. Note that we don't set the alarm in debugging |
aa3378df | 1686 | * mode; it is just annoying to have the server exit just when you |
1687 | * are about to discover the bug. | |
1688 | */ | |
f00d1f78 | 1689 | signal(SIGALRM, grace_alarm_handler); |
5260325f | 1690 | if (!debug_flag) |
1691 | alarm(options.login_grace_time); | |
1692 | ||
7368a6c8 | 1693 | sshd_exchange_identification(sock_in, sock_out); |
0598d99d | 1694 | |
5260325f | 1695 | packet_set_nonblocking(); |
1696 | ||
2362db19 | 1697 | /* allocate authentication context */ |
1698 | authctxt = xmalloc(sizeof(*authctxt)); | |
1699 | memset(authctxt, 0, sizeof(*authctxt)); | |
1700 | ||
1b394137 | 1701 | authctxt->loginmsg = &loginmsg; |
1702 | ||
2362db19 | 1703 | /* XXX global for cleanup, access from other modules */ |
1704 | the_authctxt = authctxt; | |
1705 | ||
022487ce | 1706 | /* prepare buffer to collect messages to display to user after login */ |
1707 | buffer_init(&loginmsg); | |
1708 | ||
324bf712 | 1709 | if (use_privsep) |
2362db19 | 1710 | if (privsep_preauth(authctxt) == 1) |
324bf712 | 1711 | goto authenticated; |
1853d1ef | 1712 | |
7b2ea3a1 | 1713 | /* perform the key exchange */ |
7b2ea3a1 | 1714 | /* authenticate user and start session */ |
e78a59f5 | 1715 | if (compat20) { |
1716 | do_ssh2_kex(); | |
2362db19 | 1717 | do_authentication2(authctxt); |
e78a59f5 | 1718 | } else { |
1719 | do_ssh1_kex(); | |
2362db19 | 1720 | do_authentication(authctxt); |
e78a59f5 | 1721 | } |
324bf712 | 1722 | /* |
1723 | * If we use privilege separation, the unprivileged child transfers | |
1724 | * the current keystate and exits | |
1725 | */ | |
1726 | if (use_privsep) { | |
b5a28cbc | 1727 | mm_send_keystate(pmonitor); |
1853d1ef | 1728 | exit(0); |
324bf712 | 1729 | } |
1853d1ef | 1730 | |
1731 | authenticated: | |
678143bd | 1732 | /* |
1733 | * Cancel the alarm we set to limit the time taken for | |
1734 | * authentication. | |
1735 | */ | |
1736 | alarm(0); | |
1737 | signal(SIGALRM, SIG_DFL); | |
1738 | if (startup_pipe != -1) { | |
1739 | close(startup_pipe); | |
1740 | startup_pipe = -1; | |
1741 | } | |
1742 | ||
6039eeef | 1743 | #ifdef SSH_AUDIT_EVENTS |
1744 | audit_event(SSH_AUTH_SUCCESS); | |
c00e4d75 | 1745 | #endif |
1746 | ||
762715ce | 1747 | /* |
1853d1ef | 1748 | * In privilege separation, we fork another child and prepare |
1749 | * file descriptor passing. | |
1750 | */ | |
1751 | if (use_privsep) { | |
324bf712 | 1752 | privsep_postauth(authctxt); |
1753 | /* the monitor process [priv] will not return */ | |
1853d1ef | 1754 | if (!compat20) |
1755 | destroy_sensitive_data(); | |
1756 | } | |
1b34c1b3 | 1757 | |
2362db19 | 1758 | /* Start session. */ |
1b34c1b3 | 1759 | do_authenticated(authctxt); |
1760 | ||
63284fbb | 1761 | /* The connection has been terminated. */ |
1762 | verbose("Closing connection to %.100s", remote_ip); | |
8efc0c15 | 1763 | |
d94aa2ae | 1764 | #ifdef USE_PAM |
7fceb20d | 1765 | if (options.use_pam) |
1766 | finish_pam(); | |
d94aa2ae | 1767 | #endif /* USE_PAM */ |
8efc0c15 | 1768 | |
2b0c0925 | 1769 | #ifdef SSH_AUDIT_EVENTS |
1770 | PRIVSEP(audit_event(SSH_CONNECTION_CLOSE)); | |
1771 | #endif | |
1772 | ||
5260325f | 1773 | packet_close(); |
1853d1ef | 1774 | |
1775 | if (use_privsep) | |
1776 | mm_terminate(); | |
1777 | ||
5260325f | 1778 | exit(0); |
1779 | } | |
8efc0c15 | 1780 | |
4f08e98d | 1781 | /* |
1782 | * Decrypt session_key_int using our private server key and private host key | |
1783 | * (key with larger modulus first). | |
1784 | */ | |
1853d1ef | 1785 | int |
4f08e98d | 1786 | ssh1_session_key(BIGNUM *session_key_int) |
1787 | { | |
1788 | int rsafail = 0; | |
1789 | ||
1790 | if (BN_cmp(sensitive_data.server_key->rsa->n, sensitive_data.ssh1_host_key->rsa->n) > 0) { | |
1791 | /* Server key has bigger modulus. */ | |
1792 | if (BN_num_bits(sensitive_data.server_key->rsa->n) < | |
1793 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + SSH_KEY_BITS_RESERVED) { | |
1794 | fatal("do_connection: %s: server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d", | |
1795 | get_remote_ipaddr(), | |
1796 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
1797 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), | |
1798 | SSH_KEY_BITS_RESERVED); | |
1799 | } | |
1800 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1801 | sensitive_data.server_key->rsa) <= 0) | |
1802 | rsafail++; | |
1803 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1804 | sensitive_data.ssh1_host_key->rsa) <= 0) | |
1805 | rsafail++; | |
1806 | } else { | |
1807 | /* Host key has bigger modulus (or they are equal). */ | |
1808 | if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) < | |
1809 | BN_num_bits(sensitive_data.server_key->rsa->n) + SSH_KEY_BITS_RESERVED) { | |
1810 | fatal("do_connection: %s: host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d", | |
1811 | get_remote_ipaddr(), | |
1812 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), | |
1813 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
1814 | SSH_KEY_BITS_RESERVED); | |
1815 | } | |
1816 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1817 | sensitive_data.ssh1_host_key->rsa) < 0) | |
1818 | rsafail++; | |
1819 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1820 | sensitive_data.server_key->rsa) < 0) | |
1821 | rsafail++; | |
1822 | } | |
1823 | return (rsafail); | |
1824 | } | |
5260325f | 1825 | /* |
7b2ea3a1 | 1826 | * SSH1 key exchange |
5260325f | 1827 | */ |
396c147e | 1828 | static void |
1e3b8b07 | 1829 | do_ssh1_kex(void) |
8efc0c15 | 1830 | { |
5260325f | 1831 | int i, len; |
46aa2d1f | 1832 | int rsafail = 0; |
5260325f | 1833 | BIGNUM *session_key_int; |
1e3b8b07 | 1834 | u_char session_key[SSH_SESSION_KEY_LENGTH]; |
1835 | u_char cookie[8]; | |
1836 | u_int cipher_type, auth_mask, protocol_flags; | |
7fdc56c5 | 1837 | u_int32_t rnd = 0; |
5260325f | 1838 | |
aa3378df | 1839 | /* |
1840 | * Generate check bytes that the client must send back in the user | |
1841 | * packet in order for it to be accepted; this is used to defy ip | |
1842 | * spoofing attacks. Note that this only works against somebody | |
1843 | * doing IP spoofing from a remote machine; any machine on the local | |
1844 | * network can still see outgoing packets and catch the random | |
1845 | * cookie. This only affects rhosts authentication, and this is one | |
1846 | * of the reasons why it is inherently insecure. | |
1847 | */ | |
5260325f | 1848 | for (i = 0; i < 8; i++) { |
1849 | if (i % 4 == 0) | |
7fdc56c5 | 1850 | rnd = arc4random(); |
1851 | cookie[i] = rnd & 0xff; | |
1852 | rnd >>= 8; | |
5260325f | 1853 | } |
1854 | ||
aa3378df | 1855 | /* |
1856 | * Send our public key. We include in the packet 64 bits of random | |
1857 | * data that must be matched in the reply in order to prevent IP | |
1858 | * spoofing. | |
1859 | */ | |
5260325f | 1860 | packet_start(SSH_SMSG_PUBLIC_KEY); |
1861 | for (i = 0; i < 8; i++) | |
7b2ea3a1 | 1862 | packet_put_char(cookie[i]); |
5260325f | 1863 | |
1864 | /* Store our public server RSA key. */ | |
fa08c86b | 1865 | packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n)); |
1866 | packet_put_bignum(sensitive_data.server_key->rsa->e); | |
1867 | packet_put_bignum(sensitive_data.server_key->rsa->n); | |
5260325f | 1868 | |
1869 | /* Store our public host RSA key. */ | |
fa08c86b | 1870 | packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); |
1871 | packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e); | |
1872 | packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n); | |
5260325f | 1873 | |
1874 | /* Put protocol flags. */ | |
1875 | packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN); | |
1876 | ||
1877 | /* Declare which ciphers we support. */ | |
94ec8c6b | 1878 | packet_put_int(cipher_mask_ssh1(0)); |
5260325f | 1879 | |
1880 | /* Declare supported authentication types. */ | |
1881 | auth_mask = 0; | |
5260325f | 1882 | if (options.rhosts_rsa_authentication) |
1883 | auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA; | |
1884 | if (options.rsa_authentication) | |
1885 | auth_mask |= 1 << SSH_AUTH_RSA; | |
5ba55ada | 1886 | if (options.challenge_response_authentication == 1) |
5260325f | 1887 | auth_mask |= 1 << SSH_AUTH_TIS; |
5260325f | 1888 | if (options.password_authentication) |
1889 | auth_mask |= 1 << SSH_AUTH_PASSWORD; | |
1890 | packet_put_int(auth_mask); | |
1891 | ||
1892 | /* Send the packet and wait for it to be sent. */ | |
1893 | packet_send(); | |
1894 | packet_write_wait(); | |
1895 | ||
fa08c86b | 1896 | debug("Sent %d bit server key and %d bit host key.", |
1897 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
1898 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); | |
5260325f | 1899 | |
1900 | /* Read clients reply (cipher type and session key). */ | |
54a5250f | 1901 | packet_read_expect(SSH_CMSG_SESSION_KEY); |
5260325f | 1902 | |
2d86a6cc | 1903 | /* Get cipher type and check whether we accept this. */ |
5260325f | 1904 | cipher_type = packet_get_char(); |
1905 | ||
94ec8c6b | 1906 | if (!(cipher_mask_ssh1(0) & (1 << cipher_type))) |
2d86a6cc | 1907 | packet_disconnect("Warning: client selects unsupported cipher."); |
1908 | ||
5260325f | 1909 | /* Get check bytes from the packet. These must match those we |
1910 | sent earlier with the public key packet. */ | |
1911 | for (i = 0; i < 8; i++) | |
7b2ea3a1 | 1912 | if (cookie[i] != packet_get_char()) |
5260325f | 1913 | packet_disconnect("IP Spoofing check bytes do not match."); |
1914 | ||
1915 | debug("Encryption type: %.200s", cipher_name(cipher_type)); | |
1916 | ||
1917 | /* Get the encrypted integer. */ | |
b775c6f2 | 1918 | if ((session_key_int = BN_new()) == NULL) |
1919 | fatal("do_ssh1_kex: BN_new failed"); | |
20b279e6 | 1920 | packet_get_bignum(session_key_int); |
5260325f | 1921 | |
5260325f | 1922 | protocol_flags = packet_get_int(); |
1923 | packet_set_protocol_flags(protocol_flags); | |
95500969 | 1924 | packet_check_eom(); |
5260325f | 1925 | |
4f08e98d | 1926 | /* Decrypt session_key_int using host/server keys */ |
1853d1ef | 1927 | rsafail = PRIVSEP(ssh1_session_key(session_key_int)); |
1928 | ||
aa3378df | 1929 | /* |
1930 | * Extract session key from the decrypted integer. The key is in the | |
1931 | * least significant 256 bits of the integer; the first byte of the | |
1932 | * key is in the highest bits. | |
1933 | */ | |
46aa2d1f | 1934 | if (!rsafail) { |
1935 | BN_mask_bits(session_key_int, sizeof(session_key) * 8); | |
1936 | len = BN_num_bytes(session_key_int); | |
2ceb8101 | 1937 | if (len < 0 || (u_int)len > sizeof(session_key)) { |
46aa2d1f | 1938 | error("do_connection: bad session key len from %s: " |
5ca51e19 | 1939 | "session_key_int %d > sizeof(session_key) %lu", |
1940 | get_remote_ipaddr(), len, (u_long)sizeof(session_key)); | |
46aa2d1f | 1941 | rsafail++; |
1942 | } else { | |
1943 | memset(session_key, 0, sizeof(session_key)); | |
1944 | BN_bn2bin(session_key_int, | |
1945 | session_key + sizeof(session_key) - len); | |
00be5382 | 1946 | |
8bbf1fa6 | 1947 | derive_ssh1_session_id( |
f2107e97 | 1948 | sensitive_data.ssh1_host_key->rsa->n, |
8bbf1fa6 | 1949 | sensitive_data.server_key->rsa->n, |
1950 | cookie, session_id); | |
00be5382 | 1951 | /* |
1952 | * Xor the first 16 bytes of the session key with the | |
1953 | * session id. | |
1954 | */ | |
1955 | for (i = 0; i < 16; i++) | |
1956 | session_key[i] ^= session_id[i]; | |
46aa2d1f | 1957 | } |
1958 | } | |
1959 | if (rsafail) { | |
00be5382 | 1960 | int bytes = BN_num_bytes(session_key_int); |
f6b1ba8f | 1961 | u_char *buf = xmalloc(bytes); |
00be5382 | 1962 | MD5_CTX md; |
1963 | ||
bbe88b6d | 1964 | logit("do_connection: generating a fake encryption key"); |
00be5382 | 1965 | BN_bn2bin(session_key_int, buf); |
1966 | MD5_Init(&md); | |
1967 | MD5_Update(&md, buf, bytes); | |
1968 | MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); | |
1969 | MD5_Final(session_key, &md); | |
1970 | MD5_Init(&md); | |
1971 | MD5_Update(&md, session_key, 16); | |
1972 | MD5_Update(&md, buf, bytes); | |
1973 | MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); | |
1974 | MD5_Final(session_key + 16, &md); | |
1975 | memset(buf, 0, bytes); | |
1976 | xfree(buf); | |
0572fe75 | 1977 | for (i = 0; i < 16; i++) |
1978 | session_id[i] = session_key[i] ^ session_key[i + 16]; | |
46aa2d1f | 1979 | } |
1853d1ef | 1980 | /* Destroy the private and public keys. No longer. */ |
63284fbb | 1981 | destroy_sensitive_data(); |
00be5382 | 1982 | |
1853d1ef | 1983 | if (use_privsep) |
1984 | mm_ssh1_session_id(session_id); | |
1985 | ||
7b2ea3a1 | 1986 | /* Destroy the decrypted integer. It is no longer needed. */ |
1987 | BN_clear_free(session_key_int); | |
1988 | ||
5260325f | 1989 | /* Set the session key. From this on all communications will be encrypted. */ |
1990 | packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type); | |
1991 | ||
1992 | /* Destroy our copy of the session key. It is no longer needed. */ | |
1993 | memset(session_key, 0, sizeof(session_key)); | |
1994 | ||
1995 | debug("Received session key; encryption turned on."); | |
1996 | ||
c242fc96 | 1997 | /* Send an acknowledgment packet. Note that this packet is sent encrypted. */ |
5260325f | 1998 | packet_start(SSH_SMSG_SUCCESS); |
1999 | packet_send(); | |
2000 | packet_write_wait(); | |
5260325f | 2001 | } |
e78a59f5 | 2002 | |
2003 | /* | |
2004 | * SSH2 key exchange: diffie-hellman-group1-sha1 | |
2005 | */ | |
396c147e | 2006 | static void |
1e3b8b07 | 2007 | do_ssh2_kex(void) |
e78a59f5 | 2008 | { |
e78a59f5 | 2009 | Kex *kex; |
e78a59f5 | 2010 | |
a8be9f80 | 2011 | if (options.ciphers != NULL) { |
6ae2364d | 2012 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = |
a8be9f80 | 2013 | myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; |
2014 | } | |
1ad64a93 | 2015 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = |
2016 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]); | |
2017 | myproposal[PROPOSAL_ENC_ALGS_STOC] = | |
2018 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); | |
2019 | ||
b2552997 | 2020 | if (options.macs != NULL) { |
2021 | myproposal[PROPOSAL_MAC_ALGS_CTOS] = | |
2022 | myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; | |
2023 | } | |
07200973 | 2024 | if (options.compression == COMP_NONE) { |
636f76ca | 2025 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = |
2026 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "none"; | |
07200973 | 2027 | } else if (options.compression == COMP_DELAYED) { |
2028 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = | |
2029 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com"; | |
636f76ca | 2030 | } |
07200973 | 2031 | |
fa08c86b | 2032 | myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = list_hostkey_types(); |
2033 | ||
7a37c112 | 2034 | /* start key exchange */ |
d8ee838b | 2035 | kex = kex_setup(myproposal); |
98a58eda | 2036 | kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server; |
41e5bd9a | 2037 | kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server; |
98a58eda | 2038 | kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; |
a5c9ffdb | 2039 | kex->server = 1; |
2040 | kex->client_version_string=client_version_string; | |
2041 | kex->server_version_string=server_version_string; | |
2042 | kex->load_host_key=&get_hostkey_by_type; | |
1853d1ef | 2043 | kex->host_key_index=&get_hostkey_index; |
94ec8c6b | 2044 | |
7a37c112 | 2045 | xxx_kex = kex; |
2046 | ||
c422989b | 2047 | dispatch_run(DISPATCH_BLOCK, &kex->done, kex); |
94ec8c6b | 2048 | |
d1ac6175 | 2049 | session_id2 = kex->session_id; |
2050 | session_id2_len = kex->session_id_len; | |
2051 | ||
94ec8c6b | 2052 | #ifdef DEBUG_KEXDH |
2053 | /* send 1st encrypted/maced/compressed message */ | |
2054 | packet_start(SSH2_MSG_IGNORE); | |
2055 | packet_put_cstring("markus"); | |
2056 | packet_send(); | |
2057 | packet_write_wait(); | |
2058 | #endif | |
a5c9ffdb | 2059 | debug("KEX done"); |
e78a59f5 | 2060 | } |
2362db19 | 2061 | |
2062 | /* server specific fatal cleanup */ | |
2063 | void | |
2064 | cleanup_exit(int i) | |
2065 | { | |
2066 | if (the_authctxt) | |
2067 | do_cleanup(the_authctxt); | |
6039eeef | 2068 | #ifdef SSH_AUDIT_EVENTS |
c00e4d75 | 2069 | /* done after do_cleanup so it can cancel the PAM auth 'thread' */ |
2070 | if (!use_privsep || mm_is_monitor()) | |
6039eeef | 2071 | audit_event(SSH_CONNECTION_ABANDON); |
c00e4d75 | 2072 | #endif |
2362db19 | 2073 | _exit(i); |
2074 | } |