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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" | |
a75f5360 | 45 | RCSID("$OpenBSD: sshd.c,v 1.319 2006/02/08 12:15:27 stevesk Exp $"); |
46 | ||
47 | #include <paths.h> | |
8efc0c15 | 48 | |
42f11eb2 | 49 | #include <openssl/dh.h> |
50 | #include <openssl/bn.h> | |
436c347c | 51 | #include <openssl/md5.h> |
1853d1ef | 52 | #include <openssl/rand.h> |
6e879cb4 | 53 | #ifdef HAVE_SECUREWARE |
54 | #include <sys/security.h> | |
55 | #include <prot.h> | |
56 | #endif | |
42f11eb2 | 57 | |
58 | #include "ssh.h" | |
59 | #include "ssh1.h" | |
60 | #include "ssh2.h" | |
8efc0c15 | 61 | #include "xmalloc.h" |
62 | #include "rsa.h" | |
1729c161 | 63 | #include "sshpty.h" |
8efc0c15 | 64 | #include "packet.h" |
42f11eb2 | 65 | #include "log.h" |
8efc0c15 | 66 | #include "servconf.h" |
67 | #include "uidswap.h" | |
68 | #include "compat.h" | |
7368a6c8 | 69 | #include "buffer.h" |
b9a549d7 | 70 | #include "bufaux.h" |
42f11eb2 | 71 | #include "cipher.h" |
e78a59f5 | 72 | #include "kex.h" |
7368a6c8 | 73 | #include "key.h" |
94ec8c6b | 74 | #include "dh.h" |
e78a59f5 | 75 | #include "myproposal.h" |
a306f2dd | 76 | #include "authfile.h" |
42f11eb2 | 77 | #include "pathnames.h" |
78 | #include "atomicio.h" | |
79 | #include "canohost.h" | |
80 | #include "auth.h" | |
81 | #include "misc.h" | |
b9a549d7 | 82 | #include "msg.h" |
a5c9ffdb | 83 | #include "dispatch.h" |
e4d7f734 | 84 | #include "channels.h" |
1b34c1b3 | 85 | #include "session.h" |
1853d1ef | 86 | #include "monitor_mm.h" |
87 | #include "monitor.h" | |
88 | #include "monitor_wrap.h" | |
89 | #include "monitor_fdpass.h" | |
8efc0c15 | 90 | |
91 | #ifdef LIBWRAP | |
92 | #include <tcpd.h> | |
93 | #include <syslog.h> | |
94 | int allow_severity = LOG_INFO; | |
95 | int deny_severity = LOG_WARNING; | |
96 | #endif /* LIBWRAP */ | |
97 | ||
98 | #ifndef O_NOCTTY | |
99 | #define O_NOCTTY 0 | |
100 | #endif | |
101 | ||
b250e837 | 102 | /* Re-exec fds */ |
103 | #define REEXEC_DEVCRYPTO_RESERVED_FD (STDERR_FILENO + 1) | |
104 | #define REEXEC_STARTUP_PIPE_FD (STDERR_FILENO + 2) | |
105 | #define REEXEC_CONFIG_PASS_FD (STDERR_FILENO + 3) | |
106 | #define REEXEC_MIN_FREE_FD (STDERR_FILENO + 4) | |
107 | ||
260d427b | 108 | extern char *__progname; |
260d427b | 109 | |
8efc0c15 | 110 | /* Server configuration options. */ |
111 | ServerOptions options; | |
112 | ||
113 | /* Name of the server configuration file. */ | |
42f11eb2 | 114 | char *config_file_name = _PATH_SERVER_CONFIG_FILE; |
8efc0c15 | 115 | |
5260325f | 116 | /* |
117 | * Debug mode flag. This can be set on the command line. If debug | |
118 | * mode is enabled, extra debugging output will be sent to the system | |
119 | * log, the daemon will not go to background, and will exit after processing | |
120 | * the first connection. | |
121 | */ | |
8efc0c15 | 122 | int debug_flag = 0; |
123 | ||
f87f09aa | 124 | /* Flag indicating that the daemon should only test the configuration and keys. */ |
125 | int test_flag = 0; | |
126 | ||
8efc0c15 | 127 | /* Flag indicating that the daemon is being started from inetd. */ |
128 | int inetd_flag = 0; | |
129 | ||
0b6fbf03 | 130 | /* Flag indicating that sshd should not detach and become a daemon. */ |
131 | int no_daemon_flag = 0; | |
132 | ||
6a17f9c2 | 133 | /* debug goes to stderr unless inetd_flag is set */ |
134 | int log_stderr = 0; | |
135 | ||
8efc0c15 | 136 | /* Saved arguments to main(). */ |
137 | char **saved_argv; | |
4d33e531 | 138 | int saved_argc; |
8efc0c15 | 139 | |
b9a549d7 | 140 | /* re-exec */ |
141 | int rexeced_flag = 0; | |
142 | int rexec_flag = 1; | |
143 | int rexec_argc = 0; | |
144 | char **rexec_argv; | |
145 | ||
aa3378df | 146 | /* |
48e671d5 | 147 | * The sockets that the server is listening; this is used in the SIGHUP |
148 | * signal handler. | |
aa3378df | 149 | */ |
48e671d5 | 150 | #define MAX_LISTEN_SOCKS 16 |
151 | int listen_socks[MAX_LISTEN_SOCKS]; | |
152 | int num_listen_socks = 0; | |
8efc0c15 | 153 | |
aa3378df | 154 | /* |
155 | * the client's version string, passed by sshd2 in compat mode. if != NULL, | |
156 | * sshd will skip the version-number exchange | |
157 | */ | |
5260325f | 158 | char *client_version_string = NULL; |
7368a6c8 | 159 | char *server_version_string = NULL; |
8efc0c15 | 160 | |
7a37c112 | 161 | /* for rekeying XXX fixme */ |
162 | Kex *xxx_kex; | |
163 | ||
aa3378df | 164 | /* |
165 | * Any really sensitive data in the application is contained in this | |
166 | * structure. The idea is that this structure could be locked into memory so | |
167 | * that the pages do not get written into swap. However, there are some | |
168 | * problems. The private key contains BIGNUMs, and we do not (in principle) | |
169 | * have access to the internals of them, and locking just the structure is | |
170 | * not very useful. Currently, memory locking is not implemented. | |
171 | */ | |
5260325f | 172 | struct { |
cb7bd922 | 173 | Key *server_key; /* ephemeral server key */ |
fa08c86b | 174 | Key *ssh1_host_key; /* ssh1 host key */ |
175 | Key **host_keys; /* all private host keys */ | |
176 | int have_ssh1_key; | |
177 | int have_ssh2_key; | |
00be5382 | 178 | u_char ssh1_cookie[SSH_SESSION_KEY_LENGTH]; |
8efc0c15 | 179 | } sensitive_data; |
180 | ||
aa3378df | 181 | /* |
59c97189 | 182 | * Flag indicating whether the RSA server key needs to be regenerated. |
183 | * Is set in the SIGALRM handler and cleared when the key is regenerated. | |
aa3378df | 184 | */ |
7a934d1b | 185 | static volatile sig_atomic_t key_do_regen = 0; |
8efc0c15 | 186 | |
c9130033 | 187 | /* This is set to true when a signal is received. */ |
7a934d1b | 188 | static volatile sig_atomic_t received_sighup = 0; |
189 | static volatile sig_atomic_t received_sigterm = 0; | |
8efc0c15 | 190 | |
7368a6c8 | 191 | /* session identifier, used by RSA-auth */ |
1e3b8b07 | 192 | u_char session_id[16]; |
e7c0f9d5 | 193 | |
a306f2dd | 194 | /* same for ssh2 */ |
1e3b8b07 | 195 | u_char *session_id2 = NULL; |
a27002e5 | 196 | u_int session_id2_len = 0; |
a306f2dd | 197 | |
c345cf9d | 198 | /* record remote hostname or ip */ |
1e3b8b07 | 199 | u_int utmp_len = MAXHOSTNAMELEN; |
c345cf9d | 200 | |
7ace8c3b | 201 | /* options.max_startup sized array of fd ints */ |
202 | int *startup_pipes = NULL; | |
203 | int startup_pipe; /* in child */ | |
204 | ||
1853d1ef | 205 | /* variables used for privilege separation */ |
98a58eda | 206 | int use_privsep; |
a9b33b95 | 207 | struct monitor *pmonitor = NULL; |
1853d1ef | 208 | |
2362db19 | 209 | /* global authentication context */ |
210 | Authctxt *the_authctxt = NULL; | |
211 | ||
be2ca0c9 | 212 | /* message to be displayed after login */ |
213 | Buffer loginmsg; | |
214 | ||
7368a6c8 | 215 | /* Prototypes for various functions defined later in this file. */ |
396c147e | 216 | void destroy_sensitive_data(void); |
1853d1ef | 217 | void demote_sensitive_data(void); |
c8d54615 | 218 | |
396c147e | 219 | static void do_ssh1_kex(void); |
220 | static void do_ssh2_kex(void); | |
94ec8c6b | 221 | |
48e671d5 | 222 | /* |
223 | * Close all listening sockets | |
224 | */ | |
396c147e | 225 | static void |
48e671d5 | 226 | close_listen_socks(void) |
227 | { | |
228 | int i; | |
e424e241 | 229 | |
48e671d5 | 230 | for (i = 0; i < num_listen_socks; i++) |
231 | close(listen_socks[i]); | |
232 | num_listen_socks = -1; | |
233 | } | |
234 | ||
7ace8c3b | 235 | static void |
236 | close_startup_pipes(void) | |
237 | { | |
238 | int i; | |
e424e241 | 239 | |
7ace8c3b | 240 | if (startup_pipes) |
241 | for (i = 0; i < options.max_startups; i++) | |
242 | if (startup_pipes[i] != -1) | |
243 | close(startup_pipes[i]); | |
244 | } | |
245 | ||
5260325f | 246 | /* |
247 | * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP; | |
248 | * the effect is to reread the configuration file (and to regenerate | |
249 | * the server key). | |
250 | */ | |
396c147e | 251 | static void |
5260325f | 252 | sighup_handler(int sig) |
8efc0c15 | 253 | { |
6056eb35 | 254 | int save_errno = errno; |
255 | ||
5260325f | 256 | received_sighup = 1; |
257 | signal(SIGHUP, sighup_handler); | |
6056eb35 | 258 | errno = save_errno; |
8efc0c15 | 259 | } |
260 | ||
5260325f | 261 | /* |
262 | * Called from the main program after receiving SIGHUP. | |
263 | * Restarts the server. | |
264 | */ | |
396c147e | 265 | static void |
5ca51e19 | 266 | sighup_restart(void) |
8efc0c15 | 267 | { |
bbe88b6d | 268 | logit("Received SIGHUP; restarting."); |
48e671d5 | 269 | close_listen_socks(); |
7ace8c3b | 270 | close_startup_pipes(); |
5260325f | 271 | execv(saved_argv[0], saved_argv); |
bbe88b6d | 272 | logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0], |
e424e241 | 273 | strerror(errno)); |
5260325f | 274 | exit(1); |
8efc0c15 | 275 | } |
276 | ||
5260325f | 277 | /* |
278 | * Generic signal handler for terminating signals in the master daemon. | |
5260325f | 279 | */ |
396c147e | 280 | static void |
5260325f | 281 | sigterm_handler(int sig) |
8efc0c15 | 282 | { |
c9130033 | 283 | received_sigterm = sig; |
8efc0c15 | 284 | } |
285 | ||
5260325f | 286 | /* |
287 | * SIGCHLD handler. This is called whenever a child dies. This will then | |
c9130033 | 288 | * reap any zombies left by exited children. |
5260325f | 289 | */ |
396c147e | 290 | static void |
5260325f | 291 | main_sigchld_handler(int sig) |
8efc0c15 | 292 | { |
5260325f | 293 | int save_errno = errno; |
e424e241 | 294 | pid_t pid; |
5260325f | 295 | int status; |
5ad13cd7 | 296 | |
8c38e88b | 297 | while ((pid = waitpid(-1, &status, WNOHANG)) > 0 || |
298 | (pid < 0 && errno == EINTR)) | |
5260325f | 299 | ; |
5ad13cd7 | 300 | |
5260325f | 301 | signal(SIGCHLD, main_sigchld_handler); |
302 | errno = save_errno; | |
8efc0c15 | 303 | } |
304 | ||
5260325f | 305 | /* |
306 | * Signal handler for the alarm after the login grace period has expired. | |
307 | */ | |
396c147e | 308 | static void |
5260325f | 309 | grace_alarm_handler(int sig) |
8efc0c15 | 310 | { |
c9130033 | 311 | /* XXX no idea how fix this signal handler */ |
312 | ||
a9b33b95 | 313 | if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0) |
314 | kill(pmonitor->m_pid, SIGALRM); | |
315 | ||
5260325f | 316 | /* Log error and exit. */ |
26b9a3d2 | 317 | fatal("Timeout before authentication for %s", get_remote_ipaddr()); |
5260325f | 318 | } |
8efc0c15 | 319 | |
5260325f | 320 | /* |
321 | * Signal handler for the key regeneration alarm. Note that this | |
322 | * alarm only occurs in the daemon waiting for connections, and it does not | |
323 | * do anything with the private key or random state before forking. | |
324 | * Thus there should be no concurrency control/asynchronous execution | |
325 | * problems. | |
326 | */ | |
396c147e | 327 | static void |
cb7bd922 | 328 | generate_ephemeral_server_key(void) |
fa08c86b | 329 | { |
7fdc56c5 | 330 | u_int32_t rnd = 0; |
00be5382 | 331 | int i; |
332 | ||
cd332296 | 333 | verbose("Generating %s%d bit RSA key.", |
76ca7b01 | 334 | sensitive_data.server_key ? "new " : "", options.server_key_bits); |
fa08c86b | 335 | if (sensitive_data.server_key != NULL) |
336 | key_free(sensitive_data.server_key); | |
cd332296 | 337 | sensitive_data.server_key = key_generate(KEY_RSA1, |
76ca7b01 | 338 | options.server_key_bits); |
339 | verbose("RSA key generation complete."); | |
00be5382 | 340 | |
341 | for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) { | |
342 | if (i % 4 == 0) | |
7fdc56c5 | 343 | rnd = arc4random(); |
344 | sensitive_data.ssh1_cookie[i] = rnd & 0xff; | |
345 | rnd >>= 8; | |
00be5382 | 346 | } |
347 | arc4random_stir(); | |
fa08c86b | 348 | } |
f546c780 | 349 | |
396c147e | 350 | static void |
5260325f | 351 | key_regeneration_alarm(int sig) |
352 | { | |
353 | int save_errno = errno; | |
e424e241 | 354 | |
59c97189 | 355 | signal(SIGALRM, SIG_DFL); |
5260325f | 356 | errno = save_errno; |
59c97189 | 357 | key_do_regen = 1; |
5260325f | 358 | } |
8efc0c15 | 359 | |
396c147e | 360 | static void |
7368a6c8 | 361 | sshd_exchange_identification(int sock_in, int sock_out) |
362 | { | |
2ceb8101 | 363 | u_int i; |
364 | int mismatch; | |
7368a6c8 | 365 | int remote_major, remote_minor; |
a8be9f80 | 366 | int major, minor; |
7368a6c8 | 367 | char *s; |
368 | char buf[256]; /* Must not be larger than remote_version. */ | |
369 | char remote_version[256]; /* Must be at least as big as buf. */ | |
370 | ||
a8be9f80 | 371 | if ((options.protocol & SSH_PROTO_1) && |
372 | (options.protocol & SSH_PROTO_2)) { | |
373 | major = PROTOCOL_MAJOR_1; | |
374 | minor = 99; | |
375 | } else if (options.protocol & SSH_PROTO_2) { | |
376 | major = PROTOCOL_MAJOR_2; | |
377 | minor = PROTOCOL_MINOR_2; | |
378 | } else { | |
379 | major = PROTOCOL_MAJOR_1; | |
380 | minor = PROTOCOL_MINOR_1; | |
381 | } | |
382 | snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", major, minor, SSH_VERSION); | |
7368a6c8 | 383 | server_version_string = xstrdup(buf); |
384 | ||
7b390973 | 385 | /* Send our protocol version identification. */ |
386 | if (atomicio(vwrite, sock_out, server_version_string, | |
387 | strlen(server_version_string)) | |
388 | != strlen(server_version_string)) { | |
389 | logit("Could not write ident string to %s", get_remote_ipaddr()); | |
2362db19 | 390 | cleanup_exit(255); |
7b390973 | 391 | } |
392 | ||
393 | /* Read other sides version identification. */ | |
394 | memset(buf, 0, sizeof(buf)); | |
395 | for (i = 0; i < sizeof(buf) - 1; i++) { | |
396 | if (atomicio(read, sock_in, &buf[i], 1) != 1) { | |
397 | logit("Did not receive identification string from %s", | |
398 | get_remote_ipaddr()); | |
2362db19 | 399 | cleanup_exit(255); |
7368a6c8 | 400 | } |
7b390973 | 401 | if (buf[i] == '\r') { |
402 | buf[i] = 0; | |
403 | /* Kludge for F-Secure Macintosh < 1.0.2 */ | |
404 | if (i == 12 && | |
405 | strncmp(buf, "SSH-1.5-W1.0", 12) == 0) | |
7368a6c8 | 406 | break; |
7b390973 | 407 | continue; |
408 | } | |
409 | if (buf[i] == '\n') { | |
410 | buf[i] = 0; | |
411 | break; | |
7368a6c8 | 412 | } |
7368a6c8 | 413 | } |
7b390973 | 414 | buf[sizeof(buf) - 1] = 0; |
415 | client_version_string = xstrdup(buf); | |
7368a6c8 | 416 | |
417 | /* | |
418 | * Check that the versions match. In future this might accept | |
419 | * several versions and set appropriate flags to handle them. | |
420 | */ | |
421 | if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n", | |
422 | &remote_major, &remote_minor, remote_version) != 3) { | |
6ae2364d | 423 | s = "Protocol mismatch.\n"; |
dc54438a | 424 | (void) atomicio(vwrite, sock_out, s, strlen(s)); |
7368a6c8 | 425 | close(sock_in); |
426 | close(sock_out); | |
bbe88b6d | 427 | logit("Bad protocol version identification '%.100s' from %s", |
7368a6c8 | 428 | client_version_string, get_remote_ipaddr()); |
2362db19 | 429 | cleanup_exit(255); |
7368a6c8 | 430 | } |
431 | debug("Client protocol version %d.%d; client software version %.100s", | |
184eed6a | 432 | remote_major, remote_minor, remote_version); |
7368a6c8 | 433 | |
e78a59f5 | 434 | compat_datafellows(remote_version); |
435 | ||
9a87e2ac | 436 | if (datafellows & SSH_BUG_PROBE) { |
bbe88b6d | 437 | logit("probed from %s with %s. Don't panic.", |
9a87e2ac | 438 | get_remote_ipaddr(), client_version_string); |
2362db19 | 439 | cleanup_exit(255); |
9a87e2ac | 440 | } |
441 | ||
3a1c54d4 | 442 | if (datafellows & SSH_BUG_SCANNER) { |
bbe88b6d | 443 | logit("scanned from %s with %s. Don't panic.", |
3a1c54d4 | 444 | get_remote_ipaddr(), client_version_string); |
2362db19 | 445 | cleanup_exit(255); |
3a1c54d4 | 446 | } |
447 | ||
a8be9f80 | 448 | mismatch = 0; |
6aacefa7 | 449 | switch (remote_major) { |
7368a6c8 | 450 | case 1: |
a306f2dd | 451 | if (remote_minor == 99) { |
452 | if (options.protocol & SSH_PROTO_2) | |
453 | enable_compat20(); | |
454 | else | |
455 | mismatch = 1; | |
456 | break; | |
457 | } | |
a8be9f80 | 458 | if (!(options.protocol & SSH_PROTO_1)) { |
459 | mismatch = 1; | |
460 | break; | |
461 | } | |
7368a6c8 | 462 | if (remote_minor < 3) { |
089fbbd2 | 463 | packet_disconnect("Your ssh version is too old and " |
7368a6c8 | 464 | "is no longer supported. Please install a newer version."); |
465 | } else if (remote_minor == 3) { | |
466 | /* note that this disables agent-forwarding */ | |
467 | enable_compat13(); | |
468 | } | |
a8be9f80 | 469 | break; |
e78a59f5 | 470 | case 2: |
a8be9f80 | 471 | if (options.protocol & SSH_PROTO_2) { |
e78a59f5 | 472 | enable_compat20(); |
473 | break; | |
474 | } | |
475 | /* FALLTHROUGH */ | |
6ae2364d | 476 | default: |
a8be9f80 | 477 | mismatch = 1; |
478 | break; | |
479 | } | |
480 | chop(server_version_string); | |
a8be9f80 | 481 | debug("Local version string %.200s", server_version_string); |
482 | ||
483 | if (mismatch) { | |
7368a6c8 | 484 | s = "Protocol major versions differ.\n"; |
dc54438a | 485 | (void) atomicio(vwrite, sock_out, s, strlen(s)); |
7368a6c8 | 486 | close(sock_in); |
487 | close(sock_out); | |
bbe88b6d | 488 | logit("Protocol major versions differ for %s: %.200s vs. %.200s", |
a8be9f80 | 489 | get_remote_ipaddr(), |
490 | server_version_string, client_version_string); | |
2362db19 | 491 | cleanup_exit(255); |
7368a6c8 | 492 | } |
a306f2dd | 493 | } |
494 | ||
fa08c86b | 495 | /* Destroy the host and server keys. They will no longer be needed. */ |
a306f2dd | 496 | void |
497 | destroy_sensitive_data(void) | |
498 | { | |
fa08c86b | 499 | int i; |
500 | ||
501 | if (sensitive_data.server_key) { | |
502 | key_free(sensitive_data.server_key); | |
503 | sensitive_data.server_key = NULL; | |
504 | } | |
184eed6a | 505 | for (i = 0; i < options.num_host_key_files; i++) { |
fa08c86b | 506 | if (sensitive_data.host_keys[i]) { |
507 | key_free(sensitive_data.host_keys[i]); | |
508 | sensitive_data.host_keys[i] = NULL; | |
509 | } | |
510 | } | |
511 | sensitive_data.ssh1_host_key = NULL; | |
00be5382 | 512 | memset(sensitive_data.ssh1_cookie, 0, SSH_SESSION_KEY_LENGTH); |
fa08c86b | 513 | } |
fa08c86b | 514 | |
1853d1ef | 515 | /* Demote private to public keys for network child */ |
516 | void | |
517 | demote_sensitive_data(void) | |
518 | { | |
519 | Key *tmp; | |
520 | int i; | |
521 | ||
522 | if (sensitive_data.server_key) { | |
523 | tmp = key_demote(sensitive_data.server_key); | |
524 | key_free(sensitive_data.server_key); | |
525 | sensitive_data.server_key = tmp; | |
526 | } | |
527 | ||
528 | for (i = 0; i < options.num_host_key_files; i++) { | |
529 | if (sensitive_data.host_keys[i]) { | |
530 | tmp = key_demote(sensitive_data.host_keys[i]); | |
531 | key_free(sensitive_data.host_keys[i]); | |
532 | sensitive_data.host_keys[i] = tmp; | |
533 | if (tmp->type == KEY_RSA1) | |
534 | sensitive_data.ssh1_host_key = tmp; | |
535 | } | |
536 | } | |
537 | ||
538 | /* We do not clear ssh1_host key and cookie. XXX - Okay Niels? */ | |
539 | } | |
540 | ||
51aeb639 | 541 | static void |
1853d1ef | 542 | privsep_preauth_child(void) |
543 | { | |
7fdc56c5 | 544 | u_int32_t rnd[256]; |
6ded293b | 545 | gid_t gidset[1]; |
2ea6de2b | 546 | struct passwd *pw; |
e424e241 | 547 | int i; |
1853d1ef | 548 | |
549 | /* Enable challenge-response authentication for privilege separation */ | |
550 | privsep_challenge_enable(); | |
551 | ||
552 | for (i = 0; i < 256; i++) | |
7fdc56c5 | 553 | rnd[i] = arc4random(); |
554 | RAND_seed(rnd, sizeof(rnd)); | |
1853d1ef | 555 | |
556 | /* Demote the private keys to public keys. */ | |
557 | demote_sensitive_data(); | |
558 | ||
2ea6de2b | 559 | if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) |
cdc4fc39 | 560 | fatal("Privilege separation user %s does not exist", |
561 | SSH_PRIVSEP_USER); | |
2ea6de2b | 562 | memset(pw->pw_passwd, 0, strlen(pw->pw_passwd)); |
563 | endpwent(); | |
564 | ||
343288b8 | 565 | /* Change our root directory */ |
1c352e97 | 566 | if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1) |
567 | fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR, | |
568 | strerror(errno)); | |
1853d1ef | 569 | if (chdir("/") == -1) |
edfb66cb | 570 | fatal("chdir(\"/\"): %s", strerror(errno)); |
762715ce | 571 | |
1853d1ef | 572 | /* Drop our privileges */ |
2ea6de2b | 573 | debug3("privsep user:group %u:%u", (u_int)pw->pw_uid, |
574 | (u_int)pw->pw_gid); | |
87809a1f | 575 | #if 0 |
6ff58a4b | 576 | /* XXX not ready, too heavy after chroot */ |
2ea6de2b | 577 | do_setusercontext(pw); |
87809a1f | 578 | #else |
579 | gidset[0] = pw->pw_gid; | |
87809a1f | 580 | if (setgroups(1, gidset) < 0) |
581 | fatal("setgroups: %.100s", strerror(errno)); | |
582 | permanently_set_uid(pw); | |
583 | #endif | |
1853d1ef | 584 | } |
585 | ||
2362db19 | 586 | static int |
587 | privsep_preauth(Authctxt *authctxt) | |
1853d1ef | 588 | { |
1853d1ef | 589 | int status; |
324bf712 | 590 | pid_t pid; |
1853d1ef | 591 | |
324bf712 | 592 | /* Set up unprivileged child process to deal with network data */ |
b5a28cbc | 593 | pmonitor = monitor_init(); |
324bf712 | 594 | /* Store a pointer to the kex for later rekeying */ |
b5a28cbc | 595 | pmonitor->m_pkex = &xxx_kex; |
324bf712 | 596 | |
597 | pid = fork(); | |
598 | if (pid == -1) { | |
599 | fatal("fork of unprivileged child failed"); | |
600 | } else if (pid != 0) { | |
c457707e | 601 | debug2("Network child is on pid %ld", (long)pid); |
324bf712 | 602 | |
b5a28cbc | 603 | close(pmonitor->m_recvfd); |
a9b33b95 | 604 | pmonitor->m_pid = pid; |
2362db19 | 605 | monitor_child_preauth(authctxt, pmonitor); |
b5a28cbc | 606 | close(pmonitor->m_sendfd); |
324bf712 | 607 | |
608 | /* Sync memory */ | |
b5a28cbc | 609 | monitor_sync(pmonitor); |
324bf712 | 610 | |
611 | /* Wait for the child's exit status */ | |
8c38e88b | 612 | while (waitpid(pid, &status, 0) < 0) |
613 | if (errno != EINTR) | |
614 | break; | |
2362db19 | 615 | return (1); |
324bf712 | 616 | } else { |
617 | /* child */ | |
618 | ||
b5a28cbc | 619 | close(pmonitor->m_sendfd); |
324bf712 | 620 | |
621 | /* Demote the child */ | |
622 | if (getuid() == 0 || geteuid() == 0) | |
623 | privsep_preauth_child(); | |
47c36e5b | 624 | setproctitle("%s", "[net]"); |
324bf712 | 625 | } |
2362db19 | 626 | return (0); |
324bf712 | 627 | } |
628 | ||
629 | static void | |
630 | privsep_postauth(Authctxt *authctxt) | |
631 | { | |
94d8258b | 632 | #ifdef DISABLE_FD_PASSING |
d170feb1 | 633 | if (1) { |
634 | #else | |
1853d1ef | 635 | if (authctxt->pw->pw_uid == 0 || options.use_login) { |
d170feb1 | 636 | #endif |
1853d1ef | 637 | /* File descriptor passing is broken or root login */ |
1853d1ef | 638 | use_privsep = 0; |
ae25711b | 639 | goto skip; |
1853d1ef | 640 | } |
762715ce | 641 | |
1853d1ef | 642 | /* New socket pair */ |
b5a28cbc | 643 | monitor_reinit(pmonitor); |
1853d1ef | 644 | |
b5a28cbc | 645 | pmonitor->m_pid = fork(); |
646 | if (pmonitor->m_pid == -1) | |
1853d1ef | 647 | fatal("fork of unprivileged child failed"); |
b5a28cbc | 648 | else if (pmonitor->m_pid != 0) { |
c457707e | 649 | debug2("User child is on pid %ld", (long)pmonitor->m_pid); |
b5a28cbc | 650 | close(pmonitor->m_recvfd); |
f143ed33 | 651 | buffer_clear(&loginmsg); |
b5a28cbc | 652 | monitor_child_postauth(pmonitor); |
1853d1ef | 653 | |
654 | /* NEVERREACHED */ | |
655 | exit(0); | |
656 | } | |
657 | ||
b5a28cbc | 658 | close(pmonitor->m_sendfd); |
1853d1ef | 659 | |
660 | /* Demote the private keys to public keys. */ | |
661 | demote_sensitive_data(); | |
662 | ||
663 | /* Drop privileges */ | |
664 | do_setusercontext(authctxt->pw); | |
665 | ||
ae25711b | 666 | skip: |
1853d1ef | 667 | /* It is safe now to apply the key state */ |
b5a28cbc | 668 | monitor_apply_keystate(pmonitor); |
07200973 | 669 | |
670 | /* | |
671 | * Tell the packet layer that authentication was successful, since | |
672 | * this information is not part of the key state. | |
673 | */ | |
674 | packet_set_authenticated(); | |
1853d1ef | 675 | } |
676 | ||
396c147e | 677 | static char * |
fa08c86b | 678 | list_hostkey_types(void) |
679 | { | |
3469eac4 | 680 | Buffer b; |
b6c7b7b7 | 681 | const char *p; |
682 | char *ret; | |
fa08c86b | 683 | int i; |
3469eac4 | 684 | |
685 | buffer_init(&b); | |
184eed6a | 686 | for (i = 0; i < options.num_host_key_files; i++) { |
fa08c86b | 687 | Key *key = sensitive_data.host_keys[i]; |
688 | if (key == NULL) | |
689 | continue; | |
6aacefa7 | 690 | switch (key->type) { |
fa08c86b | 691 | case KEY_RSA: |
692 | case KEY_DSA: | |
3469eac4 | 693 | if (buffer_len(&b) > 0) |
694 | buffer_append(&b, ",", 1); | |
695 | p = key_ssh_name(key); | |
696 | buffer_append(&b, p, strlen(p)); | |
fa08c86b | 697 | break; |
698 | } | |
699 | } | |
3469eac4 | 700 | buffer_append(&b, "\0", 1); |
b6c7b7b7 | 701 | ret = xstrdup(buffer_ptr(&b)); |
3469eac4 | 702 | buffer_free(&b); |
b6c7b7b7 | 703 | debug("list_hostkey_types: %s", ret); |
704 | return ret; | |
fa08c86b | 705 | } |
706 | ||
1853d1ef | 707 | Key * |
fa08c86b | 708 | get_hostkey_by_type(int type) |
709 | { | |
710 | int i; | |
e424e241 | 711 | |
184eed6a | 712 | for (i = 0; i < options.num_host_key_files; i++) { |
fa08c86b | 713 | Key *key = sensitive_data.host_keys[i]; |
714 | if (key != NULL && key->type == type) | |
715 | return key; | |
716 | } | |
717 | return NULL; | |
7368a6c8 | 718 | } |
719 | ||
1853d1ef | 720 | Key * |
721 | get_hostkey_by_index(int ind) | |
722 | { | |
723 | if (ind < 0 || ind >= options.num_host_key_files) | |
724 | return (NULL); | |
725 | return (sensitive_data.host_keys[ind]); | |
726 | } | |
727 | ||
728 | int | |
729 | get_hostkey_index(Key *key) | |
730 | { | |
731 | int i; | |
e424e241 | 732 | |
1853d1ef | 733 | for (i = 0; i < options.num_host_key_files; i++) { |
734 | if (key == sensitive_data.host_keys[i]) | |
735 | return (i); | |
736 | } | |
737 | return (-1); | |
738 | } | |
739 | ||
c345cf9d | 740 | /* |
741 | * returns 1 if connection should be dropped, 0 otherwise. | |
742 | * dropping starts at connection #max_startups_begin with a probability | |
743 | * of (max_startups_rate/100). the probability increases linearly until | |
744 | * all connections are dropped for startups > max_startups | |
745 | */ | |
396c147e | 746 | static int |
c345cf9d | 747 | drop_connection(int startups) |
748 | { | |
1c5eab6f | 749 | int p, r; |
c345cf9d | 750 | |
751 | if (startups < options.max_startups_begin) | |
752 | return 0; | |
753 | if (startups >= options.max_startups) | |
754 | return 1; | |
755 | if (options.max_startups_rate == 100) | |
756 | return 1; | |
757 | ||
758 | p = 100 - options.max_startups_rate; | |
759 | p *= startups - options.max_startups_begin; | |
1c5eab6f | 760 | p /= options.max_startups - options.max_startups_begin; |
c345cf9d | 761 | p += options.max_startups_rate; |
1c5eab6f | 762 | r = arc4random() % 100; |
c345cf9d | 763 | |
e9aec1d4 | 764 | debug("drop_connection: p %d, r %d", p, r); |
c345cf9d | 765 | return (r < p) ? 1 : 0; |
766 | } | |
767 | ||
2717fa0f | 768 | static void |
769 | usage(void) | |
770 | { | |
85ac7a84 | 771 | fprintf(stderr, "%s, %s\n", |
4526e8c2 | 772 | SSH_RELEASE, SSLeay_version(SSLEAY_VERSION)); |
65edde94 | 773 | fprintf(stderr, |
774 | "usage: sshd [-46Ddeiqt] [-b bits] [-f config_file] [-g login_grace_time]\n" | |
775 | " [-h host_key_file] [-k key_gen_time] [-o option] [-p port] [-u len]\n" | |
776 | ); | |
2717fa0f | 777 | exit(1); |
778 | } | |
779 | ||
b9a549d7 | 780 | static void |
781 | send_rexec_state(int fd, Buffer *conf) | |
782 | { | |
783 | Buffer m; | |
784 | ||
785 | debug3("%s: entering fd = %d config len %d", __func__, fd, | |
786 | buffer_len(conf)); | |
787 | ||
788 | /* | |
789 | * Protocol from reexec master to child: | |
790 | * string configuration | |
791 | * u_int ephemeral_key_follows | |
792 | * bignum e (only if ephemeral_key_follows == 1) | |
793 | * bignum n " | |
794 | * bignum d " | |
795 | * bignum iqmp " | |
796 | * bignum p " | |
797 | * bignum q " | |
72f02ae7 | 798 | * string rngseed (only if OpenSSL is not self-seeded) |
b9a549d7 | 799 | */ |
800 | buffer_init(&m); | |
801 | buffer_put_cstring(&m, buffer_ptr(conf)); | |
802 | ||
f2107e97 | 803 | if (sensitive_data.server_key != NULL && |
b9a549d7 | 804 | sensitive_data.server_key->type == KEY_RSA1) { |
805 | buffer_put_int(&m, 1); | |
806 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->e); | |
807 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->n); | |
808 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->d); | |
809 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->iqmp); | |
810 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->p); | |
811 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->q); | |
812 | } else | |
813 | buffer_put_int(&m, 0); | |
814 | ||
72f02ae7 | 815 | #ifndef OPENSSL_PRNG_ONLY |
816 | rexec_send_rng_seed(&m); | |
817 | #endif | |
818 | ||
b9a549d7 | 819 | if (ssh_msg_send(fd, 0, &m) == -1) |
820 | fatal("%s: ssh_msg_send failed", __func__); | |
821 | ||
822 | buffer_free(&m); | |
823 | ||
824 | debug3("%s: done", __func__); | |
825 | } | |
826 | ||
827 | static void | |
828 | recv_rexec_state(int fd, Buffer *conf) | |
829 | { | |
830 | Buffer m; | |
831 | char *cp; | |
832 | u_int len; | |
833 | ||
834 | debug3("%s: entering fd = %d", __func__, fd); | |
835 | ||
836 | buffer_init(&m); | |
837 | ||
838 | if (ssh_msg_recv(fd, &m) == -1) | |
839 | fatal("%s: ssh_msg_recv failed", __func__); | |
840 | if (buffer_get_char(&m) != 0) | |
841 | fatal("%s: rexec version mismatch", __func__); | |
842 | ||
843 | cp = buffer_get_string(&m, &len); | |
844 | if (conf != NULL) | |
845 | buffer_append(conf, cp, len + 1); | |
846 | xfree(cp); | |
847 | ||
848 | if (buffer_get_int(&m)) { | |
849 | if (sensitive_data.server_key != NULL) | |
850 | key_free(sensitive_data.server_key); | |
851 | sensitive_data.server_key = key_new_private(KEY_RSA1); | |
852 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->e); | |
853 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->n); | |
854 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->d); | |
855 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->iqmp); | |
856 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->p); | |
857 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->q); | |
858 | rsa_generate_additional_parameters( | |
859 | sensitive_data.server_key->rsa); | |
860 | } | |
72f02ae7 | 861 | |
862 | #ifndef OPENSSL_PRNG_ONLY | |
863 | rexec_recv_rng_seed(&m); | |
864 | #endif | |
865 | ||
b9a549d7 | 866 | buffer_free(&m); |
867 | ||
868 | debug3("%s: done", __func__); | |
869 | } | |
870 | ||
5260325f | 871 | /* |
872 | * Main program for the daemon. | |
873 | */ | |
8efc0c15 | 874 | int |
875 | main(int ac, char **av) | |
876 | { | |
5260325f | 877 | extern char *optarg; |
878 | extern int optind; | |
83529a6b | 879 | int opt, j, i, fdsetsz, on = 1; |
880 | int sock_in = -1, sock_out = -1, newsock = -1; | |
9da5c3c9 | 881 | pid_t pid; |
48e671d5 | 882 | socklen_t fromlen; |
48e671d5 | 883 | fd_set *fdset; |
884 | struct sockaddr_storage from; | |
5260325f | 885 | const char *remote_ip; |
886 | int remote_port; | |
5260325f | 887 | FILE *f; |
48e671d5 | 888 | struct addrinfo *ai; |
889 | char ntop[NI_MAXHOST], strport[NI_MAXSERV]; | |
c5894280 | 890 | char *line; |
48e671d5 | 891 | int listen_sock, maxfd; |
9216f89c | 892 | int startup_p[2] = { -1 , -1 }, config_s[2] = { -1 , -1 }; |
089fbbd2 | 893 | int startups = 0; |
aeaa3d9e | 894 | Key *key; |
2362db19 | 895 | Authctxt *authctxt; |
59c97189 | 896 | int ret, key_used = 0; |
b9a549d7 | 897 | Buffer cfg; |
5260325f | 898 | |
6e879cb4 | 899 | #ifdef HAVE_SECUREWARE |
900 | (void)set_auth_parameters(ac, av); | |
901 | #endif | |
fda04d7d | 902 | __progname = ssh_get_progname(av[0]); |
264dce47 | 903 | init_rng(); |
904 | ||
d0104542 | 905 | /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */ |
4d33e531 | 906 | saved_argc = ac; |
7706b4c7 | 907 | rexec_argc = ac; |
f420d2ba | 908 | saved_argv = xmalloc(sizeof(*saved_argv) * (ac + 1)); |
d0104542 | 909 | for (i = 0; i < ac; i++) |
910 | saved_argv[i] = xstrdup(av[i]); | |
f420d2ba | 911 | saved_argv[i] = NULL; |
d0104542 | 912 | |
913 | #ifndef HAVE_SETPROCTITLE | |
914 | /* Prepare for later setproctitle emulation */ | |
915 | compat_init_setproctitle(ac, av); | |
416c732d | 916 | av = saved_argv; |
d0104542 | 917 | #endif |
5260325f | 918 | |
a4c0faa2 | 919 | if (geteuid() == 0 && setgroups(0, NULL) == -1) |
920 | debug("setgroups(): %.200s", strerror(errno)); | |
921 | ||
fd6168c1 | 922 | /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ |
923 | sanitise_stdfd(); | |
924 | ||
5260325f | 925 | /* Initialize configuration options to their default values. */ |
926 | initialize_server_options(&options); | |
927 | ||
928 | /* Parse command-line arguments. */ | |
b9a549d7 | 929 | while ((opt = getopt(ac, av, "f:p:b:k:h:g:u:o:dDeiqrtQR46")) != -1) { |
5260325f | 930 | switch (opt) { |
48e671d5 | 931 | case '4': |
31b41ceb | 932 | options.address_family = AF_INET; |
48e671d5 | 933 | break; |
934 | case '6': | |
31b41ceb | 935 | options.address_family = AF_INET6; |
48e671d5 | 936 | break; |
5260325f | 937 | case 'f': |
938 | config_file_name = optarg; | |
939 | break; | |
940 | case 'd': | |
e053cd2c | 941 | if (debug_flag == 0) { |
bcbf86ec | 942 | debug_flag = 1; |
943 | options.log_level = SYSLOG_LEVEL_DEBUG1; | |
e053cd2c | 944 | } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) |
bcbf86ec | 945 | options.log_level++; |
5260325f | 946 | break; |
0b6fbf03 | 947 | case 'D': |
948 | no_daemon_flag = 1; | |
949 | break; | |
ff14faf1 | 950 | case 'e': |
951 | log_stderr = 1; | |
952 | break; | |
5260325f | 953 | case 'i': |
954 | inetd_flag = 1; | |
955 | break; | |
b9a549d7 | 956 | case 'r': |
957 | rexec_flag = 0; | |
958 | break; | |
959 | case 'R': | |
960 | rexeced_flag = 1; | |
961 | inetd_flag = 1; | |
962 | break; | |
5260325f | 963 | case 'Q': |
9bd5b720 | 964 | /* ignored */ |
5260325f | 965 | break; |
966 | case 'q': | |
967 | options.log_level = SYSLOG_LEVEL_QUIET; | |
968 | break; | |
969 | case 'b': | |
970 | options.server_key_bits = atoi(optarg); | |
971 | break; | |
972 | case 'p': | |
48e671d5 | 973 | options.ports_from_cmdline = 1; |
bcbf86ec | 974 | if (options.num_ports >= MAX_PORTS) { |
975 | fprintf(stderr, "too many ports.\n"); | |
976 | exit(1); | |
977 | } | |
2d2a2c65 | 978 | options.ports[options.num_ports++] = a2port(optarg); |
979 | if (options.ports[options.num_ports-1] == 0) { | |
980 | fprintf(stderr, "Bad port number.\n"); | |
981 | exit(1); | |
982 | } | |
5260325f | 983 | break; |
984 | case 'g': | |
e2b1fb42 | 985 | if ((options.login_grace_time = convtime(optarg)) == -1) { |
986 | fprintf(stderr, "Invalid login grace time.\n"); | |
987 | exit(1); | |
988 | } | |
5260325f | 989 | break; |
990 | case 'k': | |
e2b1fb42 | 991 | if ((options.key_regeneration_time = convtime(optarg)) == -1) { |
992 | fprintf(stderr, "Invalid key regeneration interval.\n"); | |
993 | exit(1); | |
994 | } | |
5260325f | 995 | break; |
996 | case 'h': | |
fa08c86b | 997 | if (options.num_host_key_files >= MAX_HOSTKEYS) { |
998 | fprintf(stderr, "too many host keys.\n"); | |
999 | exit(1); | |
1000 | } | |
1001 | options.host_key_files[options.num_host_key_files++] = optarg; | |
5260325f | 1002 | break; |
f87f09aa | 1003 | case 't': |
1004 | test_flag = 1; | |
1005 | break; | |
c345cf9d | 1006 | case 'u': |
1007 | utmp_len = atoi(optarg); | |
67f04db1 | 1008 | if (utmp_len > MAXHOSTNAMELEN) { |
1009 | fprintf(stderr, "Invalid utmp length.\n"); | |
1010 | exit(1); | |
1011 | } | |
c345cf9d | 1012 | break; |
2717fa0f | 1013 | case 'o': |
c5894280 | 1014 | line = xstrdup(optarg); |
1015 | if (process_server_config_line(&options, line, | |
2717fa0f | 1016 | "command-line", 0) != 0) |
184eed6a | 1017 | exit(1); |
c5894280 | 1018 | xfree(line); |
2717fa0f | 1019 | break; |
5260325f | 1020 | case '?': |
1021 | default: | |
2717fa0f | 1022 | usage(); |
1023 | break; | |
5260325f | 1024 | } |
1025 | } | |
b9a549d7 | 1026 | if (rexeced_flag || inetd_flag) |
1027 | rexec_flag = 0; | |
1028 | if (rexec_flag && (av[0] == NULL || *av[0] != '/')) | |
1029 | fatal("sshd re-exec requires execution with an absolute path"); | |
1030 | if (rexeced_flag) | |
b250e837 | 1031 | closefrom(REEXEC_MIN_FREE_FD); |
1032 | else | |
1033 | closefrom(REEXEC_DEVCRYPTO_RESERVED_FD); | |
b9a549d7 | 1034 | |
1a92bd7e | 1035 | SSLeay_add_all_algorithms(); |
5260325f | 1036 | |
48e671d5 | 1037 | /* |
1038 | * Force logging to stderr until we have loaded the private host | |
1039 | * key (unless started from inetd) | |
1040 | */ | |
1fe6a48f | 1041 | log_init(__progname, |
980c9344 | 1042 | options.log_level == SYSLOG_LEVEL_NOT_SET ? |
1043 | SYSLOG_LEVEL_INFO : options.log_level, | |
1044 | options.log_facility == SYSLOG_FACILITY_NOT_SET ? | |
1045 | SYSLOG_FACILITY_AUTH : options.log_facility, | |
51efad8c | 1046 | log_stderr || !inetd_flag); |
48e671d5 | 1047 | |
351f44a0 | 1048 | /* |
1049 | * Unset KRB5CCNAME, otherwise the user's session may inherit it from | |
1050 | * root's environment | |
d1cf9a87 | 1051 | */ |
3bfd27d5 | 1052 | if (getenv("KRB5CCNAME") != NULL) |
1053 | unsetenv("KRB5CCNAME"); | |
1054 | ||
ef51930f | 1055 | #ifdef _UNICOS |
e5ba4718 | 1056 | /* Cray can define user privs drop all privs now! |
1a23ac2c | 1057 | * Not needed on PRIV_SU systems! |
1058 | */ | |
1059 | drop_cray_privs(); | |
1060 | #endif | |
1061 | ||
b9a549d7 | 1062 | sensitive_data.server_key = NULL; |
1063 | sensitive_data.ssh1_host_key = NULL; | |
1064 | sensitive_data.have_ssh1_key = 0; | |
1065 | sensitive_data.have_ssh2_key = 0; | |
1066 | ||
1067 | /* Fetch our configuration */ | |
1068 | buffer_init(&cfg); | |
1069 | if (rexeced_flag) | |
b250e837 | 1070 | recv_rexec_state(REEXEC_CONFIG_PASS_FD, &cfg); |
b9a549d7 | 1071 | else |
1072 | load_server_config(config_file_name, &cfg); | |
1073 | ||
1074 | parse_server_config(&options, | |
1075 | rexeced_flag ? "rexec" : config_file_name, &cfg); | |
1076 | ||
1077 | if (!rexec_flag) | |
1078 | buffer_free(&cfg); | |
5260325f | 1079 | |
72f02ae7 | 1080 | seed_rng(); |
1081 | ||
5260325f | 1082 | /* Fill in default values for those options not explicitly set. */ |
1083 | fill_default_server_options(&options); | |
1084 | ||
31b41ceb | 1085 | /* set default channel AF */ |
1086 | channel_set_af(options.address_family); | |
1087 | ||
5260325f | 1088 | /* Check that there are no remaining arguments. */ |
1089 | if (optind < ac) { | |
1090 | fprintf(stderr, "Extra argument %s.\n", av[optind]); | |
1091 | exit(1); | |
8efc0c15 | 1092 | } |
5260325f | 1093 | |
4526e8c2 | 1094 | debug("sshd version %.100s", SSH_RELEASE); |
5260325f | 1095 | |
fa08c86b | 1096 | /* load private host keys */ |
343288b8 | 1097 | sensitive_data.host_keys = xmalloc(options.num_host_key_files * |
1098 | sizeof(Key *)); | |
184eed6a | 1099 | for (i = 0; i < options.num_host_key_files; i++) |
1e3b8b07 | 1100 | sensitive_data.host_keys[i] = NULL; |
a306f2dd | 1101 | |
184eed6a | 1102 | for (i = 0; i < options.num_host_key_files; i++) { |
aeaa3d9e | 1103 | key = key_load_private(options.host_key_files[i], "", NULL); |
1104 | sensitive_data.host_keys[i] = key; | |
fa08c86b | 1105 | if (key == NULL) { |
58cfa257 | 1106 | error("Could not load host key: %s", |
1107 | options.host_key_files[i]); | |
aeaa3d9e | 1108 | sensitive_data.host_keys[i] = NULL; |
fa08c86b | 1109 | continue; |
a306f2dd | 1110 | } |
6aacefa7 | 1111 | switch (key->type) { |
fa08c86b | 1112 | case KEY_RSA1: |
1113 | sensitive_data.ssh1_host_key = key; | |
1114 | sensitive_data.have_ssh1_key = 1; | |
1115 | break; | |
1116 | case KEY_RSA: | |
1117 | case KEY_DSA: | |
1118 | sensitive_data.have_ssh2_key = 1; | |
1119 | break; | |
a306f2dd | 1120 | } |
aeaa3d9e | 1121 | debug("private host key: #%d type %d %s", i, key->type, |
1122 | key_type(key)); | |
fa08c86b | 1123 | } |
1124 | if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) { | |
bbe88b6d | 1125 | logit("Disabling protocol version 1. Could not load host key"); |
fa08c86b | 1126 | options.protocol &= ~SSH_PROTO_1; |
1127 | } | |
1128 | if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) { | |
bbe88b6d | 1129 | logit("Disabling protocol version 2. Could not load host key"); |
fa08c86b | 1130 | options.protocol &= ~SSH_PROTO_2; |
a306f2dd | 1131 | } |
6a416424 | 1132 | if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) { |
bbe88b6d | 1133 | logit("sshd: no hostkeys available -- exiting."); |
5260325f | 1134 | exit(1); |
1135 | } | |
5260325f | 1136 | |
a306f2dd | 1137 | /* Check certain values for sanity. */ |
1138 | if (options.protocol & SSH_PROTO_1) { | |
1139 | if (options.server_key_bits < 512 || | |
1140 | options.server_key_bits > 32768) { | |
1141 | fprintf(stderr, "Bad server key size.\n"); | |
1142 | exit(1); | |
1143 | } | |
1144 | /* | |
1145 | * Check that server and host key lengths differ sufficiently. This | |
1146 | * is necessary to make double encryption work with rsaref. Oh, I | |
1147 | * hate software patents. I dont know if this can go? Niels | |
1148 | */ | |
1149 | if (options.server_key_bits > | |
e424e241 | 1150 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) - |
1151 | SSH_KEY_BITS_RESERVED && options.server_key_bits < | |
1152 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + | |
1153 | SSH_KEY_BITS_RESERVED) { | |
a306f2dd | 1154 | options.server_key_bits = |
e424e241 | 1155 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + |
1156 | SSH_KEY_BITS_RESERVED; | |
a306f2dd | 1157 | debug("Forcing server key to %d bits to make it differ from host key.", |
1158 | options.server_key_bits); | |
1159 | } | |
1160 | } | |
1161 | ||
3cc54fbb | 1162 | if (use_privsep) { |
1163 | struct passwd *pw; | |
1164 | struct stat st; | |
1165 | ||
1166 | if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) | |
1167 | fatal("Privilege separation user %s does not exist", | |
1168 | SSH_PRIVSEP_USER); | |
1169 | if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) || | |
1170 | (S_ISDIR(st.st_mode) == 0)) | |
1171 | fatal("Missing privilege separation directory: %s", | |
1172 | _PATH_PRIVSEP_CHROOT_DIR); | |
b9b82dab | 1173 | |
1174 | #ifdef HAVE_CYGWIN | |
1175 | if (check_ntsec(_PATH_PRIVSEP_CHROOT_DIR) && | |
1176 | (st.st_uid != getuid () || | |
1177 | (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)) | |
1178 | #else | |
a56313d7 | 1179 | if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0) |
b9b82dab | 1180 | #endif |
5f021474 | 1181 | fatal("%s must be owned by root and not group or " |
1182 | "world-writable.", _PATH_PRIVSEP_CHROOT_DIR); | |
3cc54fbb | 1183 | } |
1184 | ||
f87f09aa | 1185 | /* Configuration looks good, so exit if in test mode. */ |
1186 | if (test_flag) | |
1187 | exit(0); | |
1188 | ||
018a5ea3 | 1189 | /* |
1190 | * Clear out any supplemental groups we may have inherited. This | |
1191 | * prevents inadvertent creation of files with bad modes (in the | |
aff51935 | 1192 | * portable version at least, it's certainly possible for PAM |
1193 | * to create a file, and we can't control the code in every | |
018a5ea3 | 1194 | * module which might be used). |
1195 | */ | |
1196 | if (setgroups(0, NULL) < 0) | |
1197 | debug("setgroups() failed: %.200s", strerror(errno)); | |
1198 | ||
b9a549d7 | 1199 | if (rexec_flag) { |
1200 | rexec_argv = xmalloc(sizeof(char *) * (rexec_argc + 2)); | |
1201 | for (i = 0; i < rexec_argc; i++) { | |
1202 | debug("rexec_argv[%d]='%s'", i, saved_argv[i]); | |
1203 | rexec_argv[i] = saved_argv[i]; | |
1204 | } | |
1205 | rexec_argv[rexec_argc] = "-R"; | |
1206 | rexec_argv[rexec_argc + 1] = NULL; | |
1207 | } | |
1208 | ||
a306f2dd | 1209 | /* Initialize the log (it is reinitialized below in case we forked). */ |
25c31d49 | 1210 | if (debug_flag && (!inetd_flag || rexeced_flag)) |
5260325f | 1211 | log_stderr = 1; |
1fe6a48f | 1212 | log_init(__progname, options.log_level, options.log_facility, log_stderr); |
5260325f | 1213 | |
a306f2dd | 1214 | /* |
1215 | * If not in debugging mode, and not started from inetd, disconnect | |
1216 | * from the controlling terminal, and fork. The original process | |
1217 | * exits. | |
1218 | */ | |
0b6fbf03 | 1219 | if (!(debug_flag || inetd_flag || no_daemon_flag)) { |
8efc0c15 | 1220 | #ifdef TIOCNOTTY |
5260325f | 1221 | int fd; |
8efc0c15 | 1222 | #endif /* TIOCNOTTY */ |
5260325f | 1223 | if (daemon(0, 0) < 0) |
1224 | fatal("daemon() failed: %.200s", strerror(errno)); | |
1225 | ||
1226 | /* Disconnect from the controlling tty. */ | |
8efc0c15 | 1227 | #ifdef TIOCNOTTY |
5ca51e19 | 1228 | fd = open(_PATH_TTY, O_RDWR | O_NOCTTY); |
5260325f | 1229 | if (fd >= 0) { |
1230 | (void) ioctl(fd, TIOCNOTTY, NULL); | |
1231 | close(fd); | |
1232 | } | |
8efc0c15 | 1233 | #endif /* TIOCNOTTY */ |
8efc0c15 | 1234 | } |
5260325f | 1235 | /* Reinitialize the log (because of the fork above). */ |
1fe6a48f | 1236 | log_init(__progname, options.log_level, options.log_facility, log_stderr); |
5260325f | 1237 | |
5260325f | 1238 | /* Initialize the random number generator. */ |
1239 | arc4random_stir(); | |
1240 | ||
1241 | /* Chdir to the root directory so that the current disk can be | |
1242 | unmounted if desired. */ | |
1243 | chdir("/"); | |
184eed6a | 1244 | |
1d3c30db | 1245 | /* ignore SIGPIPE */ |
1246 | signal(SIGPIPE, SIG_IGN); | |
5260325f | 1247 | |
5260325f | 1248 | /* Start listening for a socket, unless started from inetd. */ |
1249 | if (inetd_flag) { | |
b9a549d7 | 1250 | int fd; |
1251 | ||
4c8722d9 | 1252 | startup_pipe = -1; |
b9a549d7 | 1253 | if (rexeced_flag) { |
b250e837 | 1254 | close(REEXEC_CONFIG_PASS_FD); |
b9a549d7 | 1255 | sock_in = sock_out = dup(STDIN_FILENO); |
1256 | if (!debug_flag) { | |
b250e837 | 1257 | startup_pipe = dup(REEXEC_STARTUP_PIPE_FD); |
1258 | close(REEXEC_STARTUP_PIPE_FD); | |
b9a549d7 | 1259 | } |
1260 | } else { | |
1261 | sock_in = dup(STDIN_FILENO); | |
1262 | sock_out = dup(STDOUT_FILENO); | |
1263 | } | |
a306f2dd | 1264 | /* |
1265 | * We intentionally do not close the descriptors 0, 1, and 2 | |
b9a549d7 | 1266 | * as our code for setting the descriptors won't work if |
a306f2dd | 1267 | * ttyfd happens to be one of those. |
1268 | */ | |
b9a549d7 | 1269 | if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { |
1270 | dup2(fd, STDIN_FILENO); | |
1271 | dup2(fd, STDOUT_FILENO); | |
1272 | if (fd > STDOUT_FILENO) | |
1273 | close(fd); | |
1274 | } | |
5260325f | 1275 | debug("inetd sockets after dupping: %d, %d", sock_in, sock_out); |
b9a549d7 | 1276 | if ((options.protocol & SSH_PROTO_1) && |
1277 | sensitive_data.server_key == NULL) | |
cb7bd922 | 1278 | generate_ephemeral_server_key(); |
5260325f | 1279 | } else { |
48e671d5 | 1280 | for (ai = options.listen_addrs; ai; ai = ai->ai_next) { |
1281 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) | |
1282 | continue; | |
1283 | if (num_listen_socks >= MAX_LISTEN_SOCKS) | |
1284 | fatal("Too many listen sockets. " | |
1285 | "Enlarge MAX_LISTEN_SOCKS"); | |
945a9853 | 1286 | if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen, |
48e671d5 | 1287 | ntop, sizeof(ntop), strport, sizeof(strport), |
945a9853 | 1288 | NI_NUMERICHOST|NI_NUMERICSERV)) != 0) { |
1289 | error("getnameinfo failed: %.100s", | |
1290 | (ret != EAI_SYSTEM) ? gai_strerror(ret) : | |
1291 | strerror(errno)); | |
48e671d5 | 1292 | continue; |
1293 | } | |
1294 | /* Create socket for listening. */ | |
3e131a6d | 1295 | listen_sock = socket(ai->ai_family, ai->ai_socktype, |
1296 | ai->ai_protocol); | |
48e671d5 | 1297 | if (listen_sock < 0) { |
1298 | /* kernel may not support ipv6 */ | |
1299 | verbose("socket: %.100s", strerror(errno)); | |
1300 | continue; | |
1301 | } | |
170694d7 | 1302 | if (set_nonblock(listen_sock) == -1) { |
a666e3b1 | 1303 | close(listen_sock); |
1304 | continue; | |
1305 | } | |
48e671d5 | 1306 | /* |
facfd613 | 1307 | * Set socket options. |
1308 | * Allow local port reuse in TIME_WAIT. | |
48e671d5 | 1309 | */ |
facfd613 | 1310 | if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR, |
1311 | &on, sizeof(on)) == -1) | |
1312 | error("setsockopt SO_REUSEADDR: %s", strerror(errno)); | |
48e671d5 | 1313 | |
1314 | debug("Bind to port %s on %s.", strport, ntop); | |
1315 | ||
1316 | /* Bind the socket to the desired port. */ | |
32ced054 | 1317 | if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) { |
1318 | if (!ai->ai_next) | |
1319 | error("Bind to port %s on %s failed: %.200s.", | |
1320 | strport, ntop, strerror(errno)); | |
48e671d5 | 1321 | close(listen_sock); |
1322 | continue; | |
1323 | } | |
1324 | listen_socks[num_listen_socks] = listen_sock; | |
1325 | num_listen_socks++; | |
1326 | ||
1327 | /* Start listening on the port. */ | |
bbe88b6d | 1328 | logit("Server listening on %s port %s.", ntop, strport); |
fce39749 | 1329 | if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0) |
48e671d5 | 1330 | fatal("listen: %.100s", strerror(errno)); |
1331 | ||
5260325f | 1332 | } |
48e671d5 | 1333 | freeaddrinfo(options.listen_addrs); |
1334 | ||
1335 | if (!num_listen_socks) | |
1336 | fatal("Cannot bind any address."); | |
1337 | ||
3aca00a3 | 1338 | if (options.protocol & SSH_PROTO_1) |
1339 | generate_ephemeral_server_key(); | |
1340 | ||
1341 | /* | |
1342 | * Arrange to restart on SIGHUP. The handler needs | |
1343 | * listen_sock. | |
1344 | */ | |
1345 | signal(SIGHUP, sighup_handler); | |
1346 | ||
1347 | signal(SIGTERM, sigterm_handler); | |
1348 | signal(SIGQUIT, sigterm_handler); | |
1349 | ||
1350 | /* Arrange SIGCHLD to be caught. */ | |
1351 | signal(SIGCHLD, main_sigchld_handler); | |
1352 | ||
1353 | /* Write out the pid file after the sigterm handler is setup */ | |
5260325f | 1354 | if (!debug_flag) { |
aa3378df | 1355 | /* |
97fb6912 | 1356 | * Record our pid in /var/run/sshd.pid to make it |
1357 | * easier to kill the correct sshd. We don't want to | |
1358 | * do this before the bind above because the bind will | |
aa3378df | 1359 | * fail if there already is a daemon, and this will |
1360 | * overwrite any old pid in the file. | |
1361 | */ | |
3c62e7eb | 1362 | f = fopen(options.pid_file, "wb"); |
71b9ced0 | 1363 | if (f == NULL) { |
1364 | error("Couldn't create pid file \"%s\": %s", | |
1365 | options.pid_file, strerror(errno)); | |
1366 | } else { | |
c457707e | 1367 | fprintf(f, "%ld\n", (long) getpid()); |
5260325f | 1368 | fclose(f); |
1369 | } | |
8efc0c15 | 1370 | } |
5260325f | 1371 | |
48e671d5 | 1372 | /* setup fd set for listen */ |
089fbbd2 | 1373 | fdset = NULL; |
48e671d5 | 1374 | maxfd = 0; |
1375 | for (i = 0; i < num_listen_socks; i++) | |
1376 | if (listen_socks[i] > maxfd) | |
1377 | maxfd = listen_socks[i]; | |
089fbbd2 | 1378 | /* pipes connected to unauthenticated childs */ |
1379 | startup_pipes = xmalloc(options.max_startups * sizeof(int)); | |
1380 | for (i = 0; i < options.max_startups; i++) | |
1381 | startup_pipes[i] = -1; | |
48e671d5 | 1382 | |
aa3378df | 1383 | /* |
1384 | * Stay listening for connections until the system crashes or | |
1385 | * the daemon is killed with a signal. | |
1386 | */ | |
5260325f | 1387 | for (;;) { |
1388 | if (received_sighup) | |
1389 | sighup_restart(); | |
089fbbd2 | 1390 | if (fdset != NULL) |
1391 | xfree(fdset); | |
b5c334cc | 1392 | fdsetsz = howmany(maxfd+1, NFDBITS) * sizeof(fd_mask); |
089fbbd2 | 1393 | fdset = (fd_set *)xmalloc(fdsetsz); |
48e671d5 | 1394 | memset(fdset, 0, fdsetsz); |
089fbbd2 | 1395 | |
48e671d5 | 1396 | for (i = 0; i < num_listen_socks; i++) |
1397 | FD_SET(listen_socks[i], fdset); | |
089fbbd2 | 1398 | for (i = 0; i < options.max_startups; i++) |
1399 | if (startup_pipes[i] != -1) | |
1400 | FD_SET(startup_pipes[i], fdset); | |
1401 | ||
1402 | /* Wait in select until there is a connection. */ | |
59c97189 | 1403 | ret = select(maxfd+1, fdset, NULL, NULL, NULL); |
1404 | if (ret < 0 && errno != EINTR) | |
1405 | error("select: %.100s", strerror(errno)); | |
c9130033 | 1406 | if (received_sigterm) { |
bbe88b6d | 1407 | logit("Received signal %d; terminating.", |
010f9726 | 1408 | (int) received_sigterm); |
c9130033 | 1409 | close_listen_socks(); |
1410 | unlink(options.pid_file); | |
1411 | exit(255); | |
1412 | } | |
59c97189 | 1413 | if (key_used && key_do_regen) { |
cb7bd922 | 1414 | generate_ephemeral_server_key(); |
59c97189 | 1415 | key_used = 0; |
1416 | key_do_regen = 0; | |
48e671d5 | 1417 | } |
59c97189 | 1418 | if (ret < 0) |
1419 | continue; | |
1420 | ||
089fbbd2 | 1421 | for (i = 0; i < options.max_startups; i++) |
1422 | if (startup_pipes[i] != -1 && | |
1423 | FD_ISSET(startup_pipes[i], fdset)) { | |
1424 | /* | |
1425 | * the read end of the pipe is ready | |
1426 | * if the child has closed the pipe | |
8abcdba4 | 1427 | * after successful authentication |
089fbbd2 | 1428 | * or if the child has died |
1429 | */ | |
1430 | close(startup_pipes[i]); | |
1431 | startup_pipes[i] = -1; | |
1432 | startups--; | |
1433 | } | |
48e671d5 | 1434 | for (i = 0; i < num_listen_socks; i++) { |
1435 | if (!FD_ISSET(listen_socks[i], fdset)) | |
5260325f | 1436 | continue; |
089fbbd2 | 1437 | fromlen = sizeof(from); |
1438 | newsock = accept(listen_socks[i], (struct sockaddr *)&from, | |
1439 | &fromlen); | |
1440 | if (newsock < 0) { | |
1441 | if (errno != EINTR && errno != EWOULDBLOCK) | |
1442 | error("accept: %.100s", strerror(errno)); | |
1443 | continue; | |
1444 | } | |
170694d7 | 1445 | if (unset_nonblock(newsock) == -1) { |
a666e3b1 | 1446 | close(newsock); |
1447 | continue; | |
1448 | } | |
c345cf9d | 1449 | if (drop_connection(startups) == 1) { |
1450 | debug("drop connection #%d", startups); | |
089fbbd2 | 1451 | close(newsock); |
1452 | continue; | |
1453 | } | |
1454 | if (pipe(startup_p) == -1) { | |
1455 | close(newsock); | |
1456 | continue; | |
1457 | } | |
1458 | ||
b9a549d7 | 1459 | if (rexec_flag && socketpair(AF_UNIX, |
1460 | SOCK_STREAM, 0, config_s) == -1) { | |
1461 | error("reexec socketpair: %s", | |
1462 | strerror(errno)); | |
1463 | close(newsock); | |
1464 | close(startup_p[0]); | |
1465 | close(startup_p[1]); | |
1466 | continue; | |
1467 | } | |
1468 | ||
089fbbd2 | 1469 | for (j = 0; j < options.max_startups; j++) |
1470 | if (startup_pipes[j] == -1) { | |
1471 | startup_pipes[j] = startup_p[0]; | |
1472 | if (maxfd < startup_p[0]) | |
1473 | maxfd = startup_p[0]; | |
1474 | startups++; | |
1475 | break; | |
1476 | } | |
2b87da3b | 1477 | |
aa3378df | 1478 | /* |
089fbbd2 | 1479 | * Got connection. Fork a child to handle it, unless |
1480 | * we are in debugging mode. | |
aa3378df | 1481 | */ |
089fbbd2 | 1482 | if (debug_flag) { |
aa3378df | 1483 | /* |
089fbbd2 | 1484 | * In debugging mode. Close the listening |
1485 | * socket, and start processing the | |
1486 | * connection without forking. | |
aa3378df | 1487 | */ |
089fbbd2 | 1488 | debug("Server will not fork when running in debugging mode."); |
48e671d5 | 1489 | close_listen_socks(); |
5260325f | 1490 | sock_in = newsock; |
1491 | sock_out = newsock; | |
b9a549d7 | 1492 | close(startup_p[0]); |
1493 | close(startup_p[1]); | |
5540ea9b | 1494 | startup_pipe = -1; |
3f7a7e4a | 1495 | pid = getpid(); |
b9a549d7 | 1496 | if (rexec_flag) { |
1497 | send_rexec_state(config_s[0], | |
1498 | &cfg); | |
1499 | close(config_s[0]); | |
1500 | } | |
5260325f | 1501 | break; |
089fbbd2 | 1502 | } else { |
1503 | /* | |
1504 | * Normal production daemon. Fork, and have | |
1505 | * the child process the connection. The | |
1506 | * parent continues listening. | |
1507 | */ | |
1508 | if ((pid = fork()) == 0) { | |
1509 | /* | |
1510 | * Child. Close the listening and max_startup | |
1511 | * sockets. Start using the accepted socket. | |
1512 | * Reinitialize logging (since our pid has | |
1513 | * changed). We break out of the loop to handle | |
1514 | * the connection. | |
1515 | */ | |
1516 | startup_pipe = startup_p[1]; | |
7ace8c3b | 1517 | close_startup_pipes(); |
089fbbd2 | 1518 | close_listen_socks(); |
1519 | sock_in = newsock; | |
1520 | sock_out = newsock; | |
1fe6a48f | 1521 | log_init(__progname, options.log_level, options.log_facility, log_stderr); |
9216f89c | 1522 | if (rexec_flag) |
1523 | close(config_s[0]); | |
089fbbd2 | 1524 | break; |
1525 | } | |
5260325f | 1526 | } |
5260325f | 1527 | |
089fbbd2 | 1528 | /* Parent. Stay in the loop. */ |
1529 | if (pid < 0) | |
1530 | error("fork: %.100s", strerror(errno)); | |
1531 | else | |
c457707e | 1532 | debug("Forked child %ld.", (long)pid); |
5260325f | 1533 | |
089fbbd2 | 1534 | close(startup_p[1]); |
5260325f | 1535 | |
b9a549d7 | 1536 | if (rexec_flag) { |
1537 | send_rexec_state(config_s[0], &cfg); | |
1538 | close(config_s[0]); | |
1539 | close(config_s[1]); | |
1540 | } | |
1541 | ||
089fbbd2 | 1542 | /* Mark that the key has been used (it was "given" to the child). */ |
59c97189 | 1543 | if ((options.protocol & SSH_PROTO_1) && |
1544 | key_used == 0) { | |
1545 | /* Schedule server key regeneration alarm. */ | |
f00d1f78 | 1546 | signal(SIGALRM, key_regeneration_alarm); |
59c97189 | 1547 | alarm(options.key_regeneration_time); |
1548 | key_used = 1; | |
1549 | } | |
5260325f | 1550 | |
089fbbd2 | 1551 | arc4random_stir(); |
1552 | ||
1553 | /* Close the new socket (the child is now taking care of it). */ | |
1554 | close(newsock); | |
1555 | } | |
48e671d5 | 1556 | /* child process check (or debug mode) */ |
1557 | if (num_listen_socks < 0) | |
1558 | break; | |
5260325f | 1559 | } |
1560 | } | |
8efc0c15 | 1561 | |
5260325f | 1562 | /* This is the child processing a new connection. */ |
cc120685 | 1563 | setproctitle("%s", "[accepted]"); |
5260325f | 1564 | |
8b758bd2 | 1565 | /* |
1566 | * Create a new session and process group since the 4.4BSD | |
1567 | * setlogin() affects the entire process group. We don't | |
1568 | * want the child to be able to affect the parent. | |
1569 | */ | |
1570 | #if !defined(SSHD_ACQUIRES_CTTY) | |
1571 | /* | |
1572 | * If setsid is called, on some platforms sshd will later acquire a | |
1573 | * controlling terminal which will result in "could not set | |
1574 | * controlling tty" errors. | |
1575 | */ | |
1576 | if (!debug_flag && !inetd_flag && setsid() < 0) | |
1577 | error("setsid: %.100s", strerror(errno)); | |
1578 | #endif | |
1579 | ||
b9a549d7 | 1580 | if (rexec_flag) { |
1581 | int fd; | |
1582 | ||
b250e837 | 1583 | debug("rexec start in %d out %d newsock %d pipe %d sock %d", |
1584 | sock_in, sock_out, newsock, startup_pipe, config_s[0]); | |
b9a549d7 | 1585 | dup2(newsock, STDIN_FILENO); |
1586 | dup2(STDIN_FILENO, STDOUT_FILENO); | |
1587 | if (startup_pipe == -1) | |
b250e837 | 1588 | close(REEXEC_STARTUP_PIPE_FD); |
b9a549d7 | 1589 | else |
b250e837 | 1590 | dup2(startup_pipe, REEXEC_STARTUP_PIPE_FD); |
b9a549d7 | 1591 | |
b250e837 | 1592 | dup2(config_s[1], REEXEC_CONFIG_PASS_FD); |
b9a549d7 | 1593 | close(config_s[1]); |
ad148c04 | 1594 | if (startup_pipe != -1) |
1595 | close(startup_pipe); | |
b250e837 | 1596 | |
b9a549d7 | 1597 | execv(rexec_argv[0], rexec_argv); |
1598 | ||
1599 | /* Reexec has failed, fall back and continue */ | |
1600 | error("rexec of %s failed: %s", rexec_argv[0], strerror(errno)); | |
b250e837 | 1601 | recv_rexec_state(REEXEC_CONFIG_PASS_FD, NULL); |
b9a549d7 | 1602 | log_init(__progname, options.log_level, |
1603 | options.log_facility, log_stderr); | |
1604 | ||
1605 | /* Clean up fds */ | |
b250e837 | 1606 | startup_pipe = REEXEC_STARTUP_PIPE_FD; |
b9a549d7 | 1607 | close(config_s[1]); |
b250e837 | 1608 | close(REEXEC_CONFIG_PASS_FD); |
1609 | newsock = sock_out = sock_in = dup(STDIN_FILENO); | |
b9a549d7 | 1610 | if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { |
1611 | dup2(fd, STDIN_FILENO); | |
1612 | dup2(fd, STDOUT_FILENO); | |
1613 | if (fd > STDERR_FILENO) | |
1614 | close(fd); | |
1615 | } | |
b250e837 | 1616 | debug("rexec cleanup in %d out %d newsock %d pipe %d sock %d", |
1617 | sock_in, sock_out, newsock, startup_pipe, config_s[0]); | |
b9a549d7 | 1618 | } |
1619 | ||
aa3378df | 1620 | /* |
1621 | * Disable the key regeneration alarm. We will not regenerate the | |
1622 | * key since we are no longer in a position to give it to anyone. We | |
1623 | * will not restart on SIGHUP since it no longer makes sense. | |
1624 | */ | |
5260325f | 1625 | alarm(0); |
1626 | signal(SIGALRM, SIG_DFL); | |
1627 | signal(SIGHUP, SIG_DFL); | |
1628 | signal(SIGTERM, SIG_DFL); | |
1629 | signal(SIGQUIT, SIG_DFL); | |
1630 | signal(SIGCHLD, SIG_DFL); | |
9aaf9be4 | 1631 | signal(SIGINT, SIG_DFL); |
5260325f | 1632 | |
aa3378df | 1633 | /* |
1634 | * Register our connection. This turns encryption off because we do | |
1635 | * not have a key. | |
1636 | */ | |
5260325f | 1637 | packet_set_connection(sock_in, sock_out); |
07200973 | 1638 | packet_set_server(); |
5260325f | 1639 | |
7c3bc5a2 | 1640 | /* Set SO_KEEPALIVE if requested. */ |
1641 | if (options.tcp_keep_alive && packet_connection_is_on_socket() && | |
1642 | setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) < 0) | |
1643 | error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); | |
1644 | ||
29798ed0 | 1645 | if ((remote_port = get_remote_port()) < 0) { |
1646 | debug("get_remote_port failed"); | |
1647 | cleanup_exit(255); | |
1648 | } | |
3a85986d | 1649 | |
1650 | /* | |
1651 | * We use get_canonical_hostname with usedns = 0 instead of | |
1652 | * get_remote_ipaddr here so IP options will be checked. | |
1653 | */ | |
1654 | remote_ip = get_canonical_hostname(0); | |
5260325f | 1655 | |
6039eeef | 1656 | #ifdef SSH_AUDIT_EVENTS |
c00e4d75 | 1657 | audit_connection_from(remote_ip, remote_port); |
1658 | #endif | |
5260325f | 1659 | #ifdef LIBWRAP |
ac28afd8 | 1660 | /* Check whether logins are denied from this host. */ |
33e5359c | 1661 | if (packet_connection_is_on_socket()) { |
5260325f | 1662 | struct request_info req; |
8efc0c15 | 1663 | |
8fbc356d | 1664 | request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0); |
5260325f | 1665 | fromhost(&req); |
8efc0c15 | 1666 | |
5260325f | 1667 | if (!hosts_access(&req)) { |
ac28afd8 | 1668 | debug("Connection refused by tcp wrapper"); |
563834bb | 1669 | refuse(&req); |
ac28afd8 | 1670 | /* NOTREACHED */ |
1671 | fatal("libwrap refuse returns"); | |
5260325f | 1672 | } |
8efc0c15 | 1673 | } |
48e671d5 | 1674 | #endif /* LIBWRAP */ |
ac28afd8 | 1675 | |
5260325f | 1676 | /* Log the connection. */ |
1677 | verbose("Connection from %.500s port %d", remote_ip, remote_port); | |
8efc0c15 | 1678 | |
aa3378df | 1679 | /* |
7b9b0103 | 1680 | * We don't want to listen forever unless the other side |
aa3378df | 1681 | * successfully authenticates itself. So we set up an alarm which is |
1682 | * cleared after successful authentication. A limit of zero | |
7b9b0103 | 1683 | * indicates no limit. Note that we don't set the alarm in debugging |
aa3378df | 1684 | * mode; it is just annoying to have the server exit just when you |
1685 | * are about to discover the bug. | |
1686 | */ | |
f00d1f78 | 1687 | signal(SIGALRM, grace_alarm_handler); |
5260325f | 1688 | if (!debug_flag) |
1689 | alarm(options.login_grace_time); | |
1690 | ||
7368a6c8 | 1691 | sshd_exchange_identification(sock_in, sock_out); |
0598d99d | 1692 | |
5260325f | 1693 | packet_set_nonblocking(); |
1694 | ||
2362db19 | 1695 | /* allocate authentication context */ |
1696 | authctxt = xmalloc(sizeof(*authctxt)); | |
1697 | memset(authctxt, 0, sizeof(*authctxt)); | |
1698 | ||
1b394137 | 1699 | authctxt->loginmsg = &loginmsg; |
1700 | ||
2362db19 | 1701 | /* XXX global for cleanup, access from other modules */ |
1702 | the_authctxt = authctxt; | |
1703 | ||
022487ce | 1704 | /* prepare buffer to collect messages to display to user after login */ |
1705 | buffer_init(&loginmsg); | |
1706 | ||
324bf712 | 1707 | if (use_privsep) |
2362db19 | 1708 | if (privsep_preauth(authctxt) == 1) |
324bf712 | 1709 | goto authenticated; |
1853d1ef | 1710 | |
7b2ea3a1 | 1711 | /* perform the key exchange */ |
7b2ea3a1 | 1712 | /* authenticate user and start session */ |
e78a59f5 | 1713 | if (compat20) { |
1714 | do_ssh2_kex(); | |
2362db19 | 1715 | do_authentication2(authctxt); |
e78a59f5 | 1716 | } else { |
1717 | do_ssh1_kex(); | |
2362db19 | 1718 | do_authentication(authctxt); |
e78a59f5 | 1719 | } |
324bf712 | 1720 | /* |
1721 | * If we use privilege separation, the unprivileged child transfers | |
1722 | * the current keystate and exits | |
1723 | */ | |
1724 | if (use_privsep) { | |
b5a28cbc | 1725 | mm_send_keystate(pmonitor); |
1853d1ef | 1726 | exit(0); |
324bf712 | 1727 | } |
1853d1ef | 1728 | |
1729 | authenticated: | |
678143bd | 1730 | /* |
1731 | * Cancel the alarm we set to limit the time taken for | |
1732 | * authentication. | |
1733 | */ | |
1734 | alarm(0); | |
1735 | signal(SIGALRM, SIG_DFL); | |
1736 | if (startup_pipe != -1) { | |
1737 | close(startup_pipe); | |
1738 | startup_pipe = -1; | |
1739 | } | |
1740 | ||
6039eeef | 1741 | #ifdef SSH_AUDIT_EVENTS |
1742 | audit_event(SSH_AUTH_SUCCESS); | |
c00e4d75 | 1743 | #endif |
1744 | ||
762715ce | 1745 | /* |
1853d1ef | 1746 | * In privilege separation, we fork another child and prepare |
1747 | * file descriptor passing. | |
1748 | */ | |
1749 | if (use_privsep) { | |
324bf712 | 1750 | privsep_postauth(authctxt); |
1751 | /* the monitor process [priv] will not return */ | |
1853d1ef | 1752 | if (!compat20) |
1753 | destroy_sensitive_data(); | |
1754 | } | |
1b34c1b3 | 1755 | |
2362db19 | 1756 | /* Start session. */ |
1b34c1b3 | 1757 | do_authenticated(authctxt); |
1758 | ||
63284fbb | 1759 | /* The connection has been terminated. */ |
1760 | verbose("Closing connection to %.100s", remote_ip); | |
8efc0c15 | 1761 | |
d94aa2ae | 1762 | #ifdef USE_PAM |
7fceb20d | 1763 | if (options.use_pam) |
1764 | finish_pam(); | |
d94aa2ae | 1765 | #endif /* USE_PAM */ |
8efc0c15 | 1766 | |
2b0c0925 | 1767 | #ifdef SSH_AUDIT_EVENTS |
1768 | PRIVSEP(audit_event(SSH_CONNECTION_CLOSE)); | |
1769 | #endif | |
1770 | ||
5260325f | 1771 | packet_close(); |
1853d1ef | 1772 | |
1773 | if (use_privsep) | |
1774 | mm_terminate(); | |
1775 | ||
5260325f | 1776 | exit(0); |
1777 | } | |
8efc0c15 | 1778 | |
4f08e98d | 1779 | /* |
1780 | * Decrypt session_key_int using our private server key and private host key | |
1781 | * (key with larger modulus first). | |
1782 | */ | |
1853d1ef | 1783 | int |
4f08e98d | 1784 | ssh1_session_key(BIGNUM *session_key_int) |
1785 | { | |
1786 | int rsafail = 0; | |
1787 | ||
1788 | if (BN_cmp(sensitive_data.server_key->rsa->n, sensitive_data.ssh1_host_key->rsa->n) > 0) { | |
1789 | /* Server key has bigger modulus. */ | |
1790 | if (BN_num_bits(sensitive_data.server_key->rsa->n) < | |
1791 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + SSH_KEY_BITS_RESERVED) { | |
1792 | fatal("do_connection: %s: server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d", | |
1793 | get_remote_ipaddr(), | |
1794 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
1795 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), | |
1796 | SSH_KEY_BITS_RESERVED); | |
1797 | } | |
1798 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1799 | sensitive_data.server_key->rsa) <= 0) | |
1800 | rsafail++; | |
1801 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1802 | sensitive_data.ssh1_host_key->rsa) <= 0) | |
1803 | rsafail++; | |
1804 | } else { | |
1805 | /* Host key has bigger modulus (or they are equal). */ | |
1806 | if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) < | |
1807 | BN_num_bits(sensitive_data.server_key->rsa->n) + SSH_KEY_BITS_RESERVED) { | |
1808 | fatal("do_connection: %s: host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d", | |
1809 | get_remote_ipaddr(), | |
1810 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), | |
1811 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
1812 | SSH_KEY_BITS_RESERVED); | |
1813 | } | |
1814 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1815 | sensitive_data.ssh1_host_key->rsa) < 0) | |
1816 | rsafail++; | |
1817 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1818 | sensitive_data.server_key->rsa) < 0) | |
1819 | rsafail++; | |
1820 | } | |
1821 | return (rsafail); | |
1822 | } | |
5260325f | 1823 | /* |
7b2ea3a1 | 1824 | * SSH1 key exchange |
5260325f | 1825 | */ |
396c147e | 1826 | static void |
1e3b8b07 | 1827 | do_ssh1_kex(void) |
8efc0c15 | 1828 | { |
5260325f | 1829 | int i, len; |
46aa2d1f | 1830 | int rsafail = 0; |
5260325f | 1831 | BIGNUM *session_key_int; |
1e3b8b07 | 1832 | u_char session_key[SSH_SESSION_KEY_LENGTH]; |
1833 | u_char cookie[8]; | |
1834 | u_int cipher_type, auth_mask, protocol_flags; | |
7fdc56c5 | 1835 | u_int32_t rnd = 0; |
5260325f | 1836 | |
aa3378df | 1837 | /* |
1838 | * Generate check bytes that the client must send back in the user | |
1839 | * packet in order for it to be accepted; this is used to defy ip | |
1840 | * spoofing attacks. Note that this only works against somebody | |
1841 | * doing IP spoofing from a remote machine; any machine on the local | |
1842 | * network can still see outgoing packets and catch the random | |
1843 | * cookie. This only affects rhosts authentication, and this is one | |
1844 | * of the reasons why it is inherently insecure. | |
1845 | */ | |
5260325f | 1846 | for (i = 0; i < 8; i++) { |
1847 | if (i % 4 == 0) | |
7fdc56c5 | 1848 | rnd = arc4random(); |
1849 | cookie[i] = rnd & 0xff; | |
1850 | rnd >>= 8; | |
5260325f | 1851 | } |
1852 | ||
aa3378df | 1853 | /* |
1854 | * Send our public key. We include in the packet 64 bits of random | |
1855 | * data that must be matched in the reply in order to prevent IP | |
1856 | * spoofing. | |
1857 | */ | |
5260325f | 1858 | packet_start(SSH_SMSG_PUBLIC_KEY); |
1859 | for (i = 0; i < 8; i++) | |
7b2ea3a1 | 1860 | packet_put_char(cookie[i]); |
5260325f | 1861 | |
1862 | /* Store our public server RSA key. */ | |
fa08c86b | 1863 | packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n)); |
1864 | packet_put_bignum(sensitive_data.server_key->rsa->e); | |
1865 | packet_put_bignum(sensitive_data.server_key->rsa->n); | |
5260325f | 1866 | |
1867 | /* Store our public host RSA key. */ | |
fa08c86b | 1868 | packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); |
1869 | packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e); | |
1870 | packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n); | |
5260325f | 1871 | |
1872 | /* Put protocol flags. */ | |
1873 | packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN); | |
1874 | ||
1875 | /* Declare which ciphers we support. */ | |
94ec8c6b | 1876 | packet_put_int(cipher_mask_ssh1(0)); |
5260325f | 1877 | |
1878 | /* Declare supported authentication types. */ | |
1879 | auth_mask = 0; | |
5260325f | 1880 | if (options.rhosts_rsa_authentication) |
1881 | auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA; | |
1882 | if (options.rsa_authentication) | |
1883 | auth_mask |= 1 << SSH_AUTH_RSA; | |
5ba55ada | 1884 | if (options.challenge_response_authentication == 1) |
5260325f | 1885 | auth_mask |= 1 << SSH_AUTH_TIS; |
5260325f | 1886 | if (options.password_authentication) |
1887 | auth_mask |= 1 << SSH_AUTH_PASSWORD; | |
1888 | packet_put_int(auth_mask); | |
1889 | ||
1890 | /* Send the packet and wait for it to be sent. */ | |
1891 | packet_send(); | |
1892 | packet_write_wait(); | |
1893 | ||
fa08c86b | 1894 | debug("Sent %d bit server key and %d bit host key.", |
1895 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
1896 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); | |
5260325f | 1897 | |
1898 | /* Read clients reply (cipher type and session key). */ | |
54a5250f | 1899 | packet_read_expect(SSH_CMSG_SESSION_KEY); |
5260325f | 1900 | |
2d86a6cc | 1901 | /* Get cipher type and check whether we accept this. */ |
5260325f | 1902 | cipher_type = packet_get_char(); |
1903 | ||
94ec8c6b | 1904 | if (!(cipher_mask_ssh1(0) & (1 << cipher_type))) |
2d86a6cc | 1905 | packet_disconnect("Warning: client selects unsupported cipher."); |
1906 | ||
5260325f | 1907 | /* Get check bytes from the packet. These must match those we |
1908 | sent earlier with the public key packet. */ | |
1909 | for (i = 0; i < 8; i++) | |
7b2ea3a1 | 1910 | if (cookie[i] != packet_get_char()) |
5260325f | 1911 | packet_disconnect("IP Spoofing check bytes do not match."); |
1912 | ||
1913 | debug("Encryption type: %.200s", cipher_name(cipher_type)); | |
1914 | ||
1915 | /* Get the encrypted integer. */ | |
b775c6f2 | 1916 | if ((session_key_int = BN_new()) == NULL) |
1917 | fatal("do_ssh1_kex: BN_new failed"); | |
20b279e6 | 1918 | packet_get_bignum(session_key_int); |
5260325f | 1919 | |
5260325f | 1920 | protocol_flags = packet_get_int(); |
1921 | packet_set_protocol_flags(protocol_flags); | |
95500969 | 1922 | packet_check_eom(); |
5260325f | 1923 | |
4f08e98d | 1924 | /* Decrypt session_key_int using host/server keys */ |
1853d1ef | 1925 | rsafail = PRIVSEP(ssh1_session_key(session_key_int)); |
1926 | ||
aa3378df | 1927 | /* |
1928 | * Extract session key from the decrypted integer. The key is in the | |
1929 | * least significant 256 bits of the integer; the first byte of the | |
1930 | * key is in the highest bits. | |
1931 | */ | |
46aa2d1f | 1932 | if (!rsafail) { |
1933 | BN_mask_bits(session_key_int, sizeof(session_key) * 8); | |
1934 | len = BN_num_bytes(session_key_int); | |
2ceb8101 | 1935 | if (len < 0 || (u_int)len > sizeof(session_key)) { |
46aa2d1f | 1936 | error("do_connection: bad session key len from %s: " |
5ca51e19 | 1937 | "session_key_int %d > sizeof(session_key) %lu", |
1938 | get_remote_ipaddr(), len, (u_long)sizeof(session_key)); | |
46aa2d1f | 1939 | rsafail++; |
1940 | } else { | |
1941 | memset(session_key, 0, sizeof(session_key)); | |
1942 | BN_bn2bin(session_key_int, | |
1943 | session_key + sizeof(session_key) - len); | |
00be5382 | 1944 | |
8bbf1fa6 | 1945 | derive_ssh1_session_id( |
f2107e97 | 1946 | sensitive_data.ssh1_host_key->rsa->n, |
8bbf1fa6 | 1947 | sensitive_data.server_key->rsa->n, |
1948 | cookie, session_id); | |
00be5382 | 1949 | /* |
1950 | * Xor the first 16 bytes of the session key with the | |
1951 | * session id. | |
1952 | */ | |
1953 | for (i = 0; i < 16; i++) | |
1954 | session_key[i] ^= session_id[i]; | |
46aa2d1f | 1955 | } |
1956 | } | |
1957 | if (rsafail) { | |
00be5382 | 1958 | int bytes = BN_num_bytes(session_key_int); |
f6b1ba8f | 1959 | u_char *buf = xmalloc(bytes); |
00be5382 | 1960 | MD5_CTX md; |
1961 | ||
bbe88b6d | 1962 | logit("do_connection: generating a fake encryption key"); |
00be5382 | 1963 | BN_bn2bin(session_key_int, buf); |
1964 | MD5_Init(&md); | |
1965 | MD5_Update(&md, buf, bytes); | |
1966 | MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); | |
1967 | MD5_Final(session_key, &md); | |
1968 | MD5_Init(&md); | |
1969 | MD5_Update(&md, session_key, 16); | |
1970 | MD5_Update(&md, buf, bytes); | |
1971 | MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); | |
1972 | MD5_Final(session_key + 16, &md); | |
1973 | memset(buf, 0, bytes); | |
1974 | xfree(buf); | |
0572fe75 | 1975 | for (i = 0; i < 16; i++) |
1976 | session_id[i] = session_key[i] ^ session_key[i + 16]; | |
46aa2d1f | 1977 | } |
1853d1ef | 1978 | /* Destroy the private and public keys. No longer. */ |
63284fbb | 1979 | destroy_sensitive_data(); |
00be5382 | 1980 | |
1853d1ef | 1981 | if (use_privsep) |
1982 | mm_ssh1_session_id(session_id); | |
1983 | ||
7b2ea3a1 | 1984 | /* Destroy the decrypted integer. It is no longer needed. */ |
1985 | BN_clear_free(session_key_int); | |
1986 | ||
5260325f | 1987 | /* Set the session key. From this on all communications will be encrypted. */ |
1988 | packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type); | |
1989 | ||
1990 | /* Destroy our copy of the session key. It is no longer needed. */ | |
1991 | memset(session_key, 0, sizeof(session_key)); | |
1992 | ||
1993 | debug("Received session key; encryption turned on."); | |
1994 | ||
c242fc96 | 1995 | /* Send an acknowledgment packet. Note that this packet is sent encrypted. */ |
5260325f | 1996 | packet_start(SSH_SMSG_SUCCESS); |
1997 | packet_send(); | |
1998 | packet_write_wait(); | |
5260325f | 1999 | } |
e78a59f5 | 2000 | |
2001 | /* | |
2002 | * SSH2 key exchange: diffie-hellman-group1-sha1 | |
2003 | */ | |
396c147e | 2004 | static void |
1e3b8b07 | 2005 | do_ssh2_kex(void) |
e78a59f5 | 2006 | { |
e78a59f5 | 2007 | Kex *kex; |
e78a59f5 | 2008 | |
a8be9f80 | 2009 | if (options.ciphers != NULL) { |
6ae2364d | 2010 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = |
a8be9f80 | 2011 | myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; |
2012 | } | |
1ad64a93 | 2013 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = |
2014 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]); | |
2015 | myproposal[PROPOSAL_ENC_ALGS_STOC] = | |
2016 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); | |
2017 | ||
b2552997 | 2018 | if (options.macs != NULL) { |
2019 | myproposal[PROPOSAL_MAC_ALGS_CTOS] = | |
2020 | myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; | |
2021 | } | |
07200973 | 2022 | if (options.compression == COMP_NONE) { |
636f76ca | 2023 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = |
2024 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "none"; | |
07200973 | 2025 | } else if (options.compression == COMP_DELAYED) { |
2026 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = | |
2027 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com"; | |
636f76ca | 2028 | } |
07200973 | 2029 | |
fa08c86b | 2030 | myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = list_hostkey_types(); |
2031 | ||
7a37c112 | 2032 | /* start key exchange */ |
d8ee838b | 2033 | kex = kex_setup(myproposal); |
98a58eda | 2034 | kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server; |
41e5bd9a | 2035 | kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server; |
98a58eda | 2036 | kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; |
a5c9ffdb | 2037 | kex->server = 1; |
2038 | kex->client_version_string=client_version_string; | |
2039 | kex->server_version_string=server_version_string; | |
2040 | kex->load_host_key=&get_hostkey_by_type; | |
1853d1ef | 2041 | kex->host_key_index=&get_hostkey_index; |
94ec8c6b | 2042 | |
7a37c112 | 2043 | xxx_kex = kex; |
2044 | ||
c422989b | 2045 | dispatch_run(DISPATCH_BLOCK, &kex->done, kex); |
94ec8c6b | 2046 | |
d1ac6175 | 2047 | session_id2 = kex->session_id; |
2048 | session_id2_len = kex->session_id_len; | |
2049 | ||
94ec8c6b | 2050 | #ifdef DEBUG_KEXDH |
2051 | /* send 1st encrypted/maced/compressed message */ | |
2052 | packet_start(SSH2_MSG_IGNORE); | |
2053 | packet_put_cstring("markus"); | |
2054 | packet_send(); | |
2055 | packet_write_wait(); | |
2056 | #endif | |
a5c9ffdb | 2057 | debug("KEX done"); |
e78a59f5 | 2058 | } |
2362db19 | 2059 | |
2060 | /* server specific fatal cleanup */ | |
2061 | void | |
2062 | cleanup_exit(int i) | |
2063 | { | |
2064 | if (the_authctxt) | |
2065 | do_cleanup(the_authctxt); | |
6039eeef | 2066 | #ifdef SSH_AUDIT_EVENTS |
c00e4d75 | 2067 | /* done after do_cleanup so it can cancel the PAM auth 'thread' */ |
2068 | if (!use_privsep || mm_is_monitor()) | |
6039eeef | 2069 | audit_event(SSH_CONNECTION_ABANDON); |
c00e4d75 | 2070 | #endif |
2362db19 | 2071 | _exit(i); |
2072 | } |