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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" | |
9f513268 | 45 | RCSID("$OpenBSD: sshd.c,v 1.325 2006/03/13 08:16:00 djm Exp $"); |
bd7c69ea | 46 | |
aa2eae64 | 47 | #include <sys/types.h> |
4095f623 | 48 | #ifdef HAVE_SYS_STAT_H |
49 | # include <sys/stat.h> | |
50 | #endif | |
51 | #include <sys/ioctl.h> | |
aa2eae64 | 52 | #include <sys/wait.h> |
a75f5360 | 53 | |
54 | #include <paths.h> | |
ada68823 | 55 | #include <signal.h> |
8efc0c15 | 56 | |
42f11eb2 | 57 | #include <openssl/dh.h> |
58 | #include <openssl/bn.h> | |
436c347c | 59 | #include <openssl/md5.h> |
1853d1ef | 60 | #include <openssl/rand.h> |
6e879cb4 | 61 | #ifdef HAVE_SECUREWARE |
62 | #include <sys/security.h> | |
63 | #include <prot.h> | |
64 | #endif | |
42f11eb2 | 65 | |
66 | #include "ssh.h" | |
67 | #include "ssh1.h" | |
68 | #include "ssh2.h" | |
8efc0c15 | 69 | #include "xmalloc.h" |
70 | #include "rsa.h" | |
1729c161 | 71 | #include "sshpty.h" |
8efc0c15 | 72 | #include "packet.h" |
42f11eb2 | 73 | #include "log.h" |
8efc0c15 | 74 | #include "servconf.h" |
75 | #include "uidswap.h" | |
76 | #include "compat.h" | |
7368a6c8 | 77 | #include "buffer.h" |
b9a549d7 | 78 | #include "bufaux.h" |
42f11eb2 | 79 | #include "cipher.h" |
e78a59f5 | 80 | #include "kex.h" |
7368a6c8 | 81 | #include "key.h" |
94ec8c6b | 82 | #include "dh.h" |
e78a59f5 | 83 | #include "myproposal.h" |
a306f2dd | 84 | #include "authfile.h" |
42f11eb2 | 85 | #include "pathnames.h" |
86 | #include "atomicio.h" | |
87 | #include "canohost.h" | |
88 | #include "auth.h" | |
89 | #include "misc.h" | |
b9a549d7 | 90 | #include "msg.h" |
a5c9ffdb | 91 | #include "dispatch.h" |
e4d7f734 | 92 | #include "channels.h" |
1b34c1b3 | 93 | #include "session.h" |
1853d1ef | 94 | #include "monitor_mm.h" |
95 | #include "monitor.h" | |
96 | #include "monitor_wrap.h" | |
97 | #include "monitor_fdpass.h" | |
8efc0c15 | 98 | |
99 | #ifdef LIBWRAP | |
100 | #include <tcpd.h> | |
101 | #include <syslog.h> | |
102 | int allow_severity = LOG_INFO; | |
103 | int deny_severity = LOG_WARNING; | |
104 | #endif /* LIBWRAP */ | |
105 | ||
106 | #ifndef O_NOCTTY | |
107 | #define O_NOCTTY 0 | |
108 | #endif | |
109 | ||
b250e837 | 110 | /* Re-exec fds */ |
111 | #define REEXEC_DEVCRYPTO_RESERVED_FD (STDERR_FILENO + 1) | |
112 | #define REEXEC_STARTUP_PIPE_FD (STDERR_FILENO + 2) | |
113 | #define REEXEC_CONFIG_PASS_FD (STDERR_FILENO + 3) | |
114 | #define REEXEC_MIN_FREE_FD (STDERR_FILENO + 4) | |
115 | ||
260d427b | 116 | extern char *__progname; |
260d427b | 117 | |
8efc0c15 | 118 | /* Server configuration options. */ |
119 | ServerOptions options; | |
120 | ||
121 | /* Name of the server configuration file. */ | |
42f11eb2 | 122 | char *config_file_name = _PATH_SERVER_CONFIG_FILE; |
8efc0c15 | 123 | |
5260325f | 124 | /* |
125 | * Debug mode flag. This can be set on the command line. If debug | |
126 | * mode is enabled, extra debugging output will be sent to the system | |
127 | * log, the daemon will not go to background, and will exit after processing | |
128 | * the first connection. | |
129 | */ | |
8efc0c15 | 130 | int debug_flag = 0; |
131 | ||
f87f09aa | 132 | /* Flag indicating that the daemon should only test the configuration and keys. */ |
133 | int test_flag = 0; | |
134 | ||
8efc0c15 | 135 | /* Flag indicating that the daemon is being started from inetd. */ |
136 | int inetd_flag = 0; | |
137 | ||
0b6fbf03 | 138 | /* Flag indicating that sshd should not detach and become a daemon. */ |
139 | int no_daemon_flag = 0; | |
140 | ||
6a17f9c2 | 141 | /* debug goes to stderr unless inetd_flag is set */ |
142 | int log_stderr = 0; | |
143 | ||
8efc0c15 | 144 | /* Saved arguments to main(). */ |
145 | char **saved_argv; | |
4d33e531 | 146 | int saved_argc; |
8efc0c15 | 147 | |
b9a549d7 | 148 | /* re-exec */ |
149 | int rexeced_flag = 0; | |
150 | int rexec_flag = 1; | |
151 | int rexec_argc = 0; | |
152 | char **rexec_argv; | |
153 | ||
aa3378df | 154 | /* |
48e671d5 | 155 | * The sockets that the server is listening; this is used in the SIGHUP |
156 | * signal handler. | |
aa3378df | 157 | */ |
48e671d5 | 158 | #define MAX_LISTEN_SOCKS 16 |
159 | int listen_socks[MAX_LISTEN_SOCKS]; | |
160 | int num_listen_socks = 0; | |
8efc0c15 | 161 | |
aa3378df | 162 | /* |
163 | * the client's version string, passed by sshd2 in compat mode. if != NULL, | |
164 | * sshd will skip the version-number exchange | |
165 | */ | |
5260325f | 166 | char *client_version_string = NULL; |
7368a6c8 | 167 | char *server_version_string = NULL; |
8efc0c15 | 168 | |
7a37c112 | 169 | /* for rekeying XXX fixme */ |
170 | Kex *xxx_kex; | |
171 | ||
aa3378df | 172 | /* |
173 | * Any really sensitive data in the application is contained in this | |
174 | * structure. The idea is that this structure could be locked into memory so | |
175 | * that the pages do not get written into swap. However, there are some | |
176 | * problems. The private key contains BIGNUMs, and we do not (in principle) | |
177 | * have access to the internals of them, and locking just the structure is | |
178 | * not very useful. Currently, memory locking is not implemented. | |
179 | */ | |
5260325f | 180 | struct { |
cb7bd922 | 181 | Key *server_key; /* ephemeral server key */ |
fa08c86b | 182 | Key *ssh1_host_key; /* ssh1 host key */ |
183 | Key **host_keys; /* all private host keys */ | |
184 | int have_ssh1_key; | |
185 | int have_ssh2_key; | |
00be5382 | 186 | u_char ssh1_cookie[SSH_SESSION_KEY_LENGTH]; |
8efc0c15 | 187 | } sensitive_data; |
188 | ||
aa3378df | 189 | /* |
59c97189 | 190 | * Flag indicating whether the RSA server key needs to be regenerated. |
191 | * Is set in the SIGALRM handler and cleared when the key is regenerated. | |
aa3378df | 192 | */ |
7a934d1b | 193 | static volatile sig_atomic_t key_do_regen = 0; |
8efc0c15 | 194 | |
c9130033 | 195 | /* This is set to true when a signal is received. */ |
7a934d1b | 196 | static volatile sig_atomic_t received_sighup = 0; |
197 | static volatile sig_atomic_t received_sigterm = 0; | |
8efc0c15 | 198 | |
7368a6c8 | 199 | /* session identifier, used by RSA-auth */ |
1e3b8b07 | 200 | u_char session_id[16]; |
e7c0f9d5 | 201 | |
a306f2dd | 202 | /* same for ssh2 */ |
1e3b8b07 | 203 | u_char *session_id2 = NULL; |
a27002e5 | 204 | u_int session_id2_len = 0; |
a306f2dd | 205 | |
c345cf9d | 206 | /* record remote hostname or ip */ |
1e3b8b07 | 207 | u_int utmp_len = MAXHOSTNAMELEN; |
c345cf9d | 208 | |
7ace8c3b | 209 | /* options.max_startup sized array of fd ints */ |
210 | int *startup_pipes = NULL; | |
211 | int startup_pipe; /* in child */ | |
212 | ||
1853d1ef | 213 | /* variables used for privilege separation */ |
98a58eda | 214 | int use_privsep; |
a9b33b95 | 215 | struct monitor *pmonitor = NULL; |
1853d1ef | 216 | |
2362db19 | 217 | /* global authentication context */ |
218 | Authctxt *the_authctxt = NULL; | |
219 | ||
be2ca0c9 | 220 | /* message to be displayed after login */ |
221 | Buffer loginmsg; | |
222 | ||
7368a6c8 | 223 | /* Prototypes for various functions defined later in this file. */ |
396c147e | 224 | void destroy_sensitive_data(void); |
1853d1ef | 225 | void demote_sensitive_data(void); |
c8d54615 | 226 | |
396c147e | 227 | static void do_ssh1_kex(void); |
228 | static void do_ssh2_kex(void); | |
94ec8c6b | 229 | |
48e671d5 | 230 | /* |
231 | * Close all listening sockets | |
232 | */ | |
396c147e | 233 | static void |
48e671d5 | 234 | close_listen_socks(void) |
235 | { | |
236 | int i; | |
e424e241 | 237 | |
48e671d5 | 238 | for (i = 0; i < num_listen_socks; i++) |
239 | close(listen_socks[i]); | |
240 | num_listen_socks = -1; | |
241 | } | |
242 | ||
7ace8c3b | 243 | static void |
244 | close_startup_pipes(void) | |
245 | { | |
246 | int i; | |
e424e241 | 247 | |
7ace8c3b | 248 | if (startup_pipes) |
249 | for (i = 0; i < options.max_startups; i++) | |
250 | if (startup_pipes[i] != -1) | |
251 | close(startup_pipes[i]); | |
252 | } | |
253 | ||
5260325f | 254 | /* |
255 | * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP; | |
256 | * the effect is to reread the configuration file (and to regenerate | |
257 | * the server key). | |
258 | */ | |
396c147e | 259 | static void |
5260325f | 260 | sighup_handler(int sig) |
8efc0c15 | 261 | { |
6056eb35 | 262 | int save_errno = errno; |
263 | ||
5260325f | 264 | received_sighup = 1; |
265 | signal(SIGHUP, sighup_handler); | |
6056eb35 | 266 | errno = save_errno; |
8efc0c15 | 267 | } |
268 | ||
5260325f | 269 | /* |
270 | * Called from the main program after receiving SIGHUP. | |
271 | * Restarts the server. | |
272 | */ | |
396c147e | 273 | static void |
5ca51e19 | 274 | sighup_restart(void) |
8efc0c15 | 275 | { |
bbe88b6d | 276 | logit("Received SIGHUP; restarting."); |
48e671d5 | 277 | close_listen_socks(); |
7ace8c3b | 278 | close_startup_pipes(); |
5260325f | 279 | execv(saved_argv[0], saved_argv); |
bbe88b6d | 280 | logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0], |
e424e241 | 281 | strerror(errno)); |
5260325f | 282 | exit(1); |
8efc0c15 | 283 | } |
284 | ||
5260325f | 285 | /* |
286 | * Generic signal handler for terminating signals in the master daemon. | |
5260325f | 287 | */ |
396c147e | 288 | static void |
5260325f | 289 | sigterm_handler(int sig) |
8efc0c15 | 290 | { |
c9130033 | 291 | received_sigterm = sig; |
8efc0c15 | 292 | } |
293 | ||
5260325f | 294 | /* |
295 | * SIGCHLD handler. This is called whenever a child dies. This will then | |
c9130033 | 296 | * reap any zombies left by exited children. |
5260325f | 297 | */ |
396c147e | 298 | static void |
5260325f | 299 | main_sigchld_handler(int sig) |
8efc0c15 | 300 | { |
5260325f | 301 | int save_errno = errno; |
e424e241 | 302 | pid_t pid; |
5260325f | 303 | int status; |
5ad13cd7 | 304 | |
8c38e88b | 305 | while ((pid = waitpid(-1, &status, WNOHANG)) > 0 || |
306 | (pid < 0 && errno == EINTR)) | |
5260325f | 307 | ; |
5ad13cd7 | 308 | |
5260325f | 309 | signal(SIGCHLD, main_sigchld_handler); |
310 | errno = save_errno; | |
8efc0c15 | 311 | } |
312 | ||
5260325f | 313 | /* |
314 | * Signal handler for the alarm after the login grace period has expired. | |
315 | */ | |
396c147e | 316 | static void |
5260325f | 317 | grace_alarm_handler(int sig) |
8efc0c15 | 318 | { |
c9130033 | 319 | /* XXX no idea how fix this signal handler */ |
320 | ||
a9b33b95 | 321 | if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0) |
322 | kill(pmonitor->m_pid, SIGALRM); | |
323 | ||
5260325f | 324 | /* Log error and exit. */ |
26b9a3d2 | 325 | fatal("Timeout before authentication for %s", get_remote_ipaddr()); |
5260325f | 326 | } |
8efc0c15 | 327 | |
5260325f | 328 | /* |
329 | * Signal handler for the key regeneration alarm. Note that this | |
330 | * alarm only occurs in the daemon waiting for connections, and it does not | |
331 | * do anything with the private key or random state before forking. | |
332 | * Thus there should be no concurrency control/asynchronous execution | |
333 | * problems. | |
334 | */ | |
396c147e | 335 | static void |
cb7bd922 | 336 | generate_ephemeral_server_key(void) |
fa08c86b | 337 | { |
7fdc56c5 | 338 | u_int32_t rnd = 0; |
00be5382 | 339 | int i; |
340 | ||
cd332296 | 341 | verbose("Generating %s%d bit RSA key.", |
76ca7b01 | 342 | sensitive_data.server_key ? "new " : "", options.server_key_bits); |
fa08c86b | 343 | if (sensitive_data.server_key != NULL) |
344 | key_free(sensitive_data.server_key); | |
cd332296 | 345 | sensitive_data.server_key = key_generate(KEY_RSA1, |
76ca7b01 | 346 | options.server_key_bits); |
347 | verbose("RSA key generation complete."); | |
00be5382 | 348 | |
349 | for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) { | |
350 | if (i % 4 == 0) | |
7fdc56c5 | 351 | rnd = arc4random(); |
352 | sensitive_data.ssh1_cookie[i] = rnd & 0xff; | |
353 | rnd >>= 8; | |
00be5382 | 354 | } |
355 | arc4random_stir(); | |
fa08c86b | 356 | } |
f546c780 | 357 | |
396c147e | 358 | static void |
5260325f | 359 | key_regeneration_alarm(int sig) |
360 | { | |
361 | int save_errno = errno; | |
e424e241 | 362 | |
59c97189 | 363 | signal(SIGALRM, SIG_DFL); |
5260325f | 364 | errno = save_errno; |
59c97189 | 365 | key_do_regen = 1; |
5260325f | 366 | } |
8efc0c15 | 367 | |
396c147e | 368 | static void |
7368a6c8 | 369 | sshd_exchange_identification(int sock_in, int sock_out) |
370 | { | |
2ceb8101 | 371 | u_int i; |
372 | int mismatch; | |
7368a6c8 | 373 | int remote_major, remote_minor; |
a8be9f80 | 374 | int major, minor; |
7368a6c8 | 375 | char *s; |
376 | char buf[256]; /* Must not be larger than remote_version. */ | |
377 | char remote_version[256]; /* Must be at least as big as buf. */ | |
378 | ||
a8be9f80 | 379 | if ((options.protocol & SSH_PROTO_1) && |
380 | (options.protocol & SSH_PROTO_2)) { | |
381 | major = PROTOCOL_MAJOR_1; | |
382 | minor = 99; | |
383 | } else if (options.protocol & SSH_PROTO_2) { | |
384 | major = PROTOCOL_MAJOR_2; | |
385 | minor = PROTOCOL_MINOR_2; | |
386 | } else { | |
387 | major = PROTOCOL_MAJOR_1; | |
388 | minor = PROTOCOL_MINOR_1; | |
389 | } | |
390 | snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", major, minor, SSH_VERSION); | |
7368a6c8 | 391 | server_version_string = xstrdup(buf); |
392 | ||
7b390973 | 393 | /* Send our protocol version identification. */ |
394 | if (atomicio(vwrite, sock_out, server_version_string, | |
395 | strlen(server_version_string)) | |
396 | != strlen(server_version_string)) { | |
397 | logit("Could not write ident string to %s", get_remote_ipaddr()); | |
2362db19 | 398 | cleanup_exit(255); |
7b390973 | 399 | } |
400 | ||
401 | /* Read other sides version identification. */ | |
402 | memset(buf, 0, sizeof(buf)); | |
403 | for (i = 0; i < sizeof(buf) - 1; i++) { | |
404 | if (atomicio(read, sock_in, &buf[i], 1) != 1) { | |
405 | logit("Did not receive identification string from %s", | |
406 | get_remote_ipaddr()); | |
2362db19 | 407 | cleanup_exit(255); |
7368a6c8 | 408 | } |
7b390973 | 409 | if (buf[i] == '\r') { |
410 | buf[i] = 0; | |
411 | /* Kludge for F-Secure Macintosh < 1.0.2 */ | |
412 | if (i == 12 && | |
413 | strncmp(buf, "SSH-1.5-W1.0", 12) == 0) | |
7368a6c8 | 414 | break; |
7b390973 | 415 | continue; |
416 | } | |
417 | if (buf[i] == '\n') { | |
418 | buf[i] = 0; | |
419 | break; | |
7368a6c8 | 420 | } |
7368a6c8 | 421 | } |
7b390973 | 422 | buf[sizeof(buf) - 1] = 0; |
423 | client_version_string = xstrdup(buf); | |
7368a6c8 | 424 | |
425 | /* | |
426 | * Check that the versions match. In future this might accept | |
427 | * several versions and set appropriate flags to handle them. | |
428 | */ | |
429 | if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n", | |
430 | &remote_major, &remote_minor, remote_version) != 3) { | |
6ae2364d | 431 | s = "Protocol mismatch.\n"; |
dc54438a | 432 | (void) atomicio(vwrite, sock_out, s, strlen(s)); |
7368a6c8 | 433 | close(sock_in); |
434 | close(sock_out); | |
bbe88b6d | 435 | logit("Bad protocol version identification '%.100s' from %s", |
7368a6c8 | 436 | client_version_string, get_remote_ipaddr()); |
2362db19 | 437 | cleanup_exit(255); |
7368a6c8 | 438 | } |
439 | debug("Client protocol version %d.%d; client software version %.100s", | |
184eed6a | 440 | remote_major, remote_minor, remote_version); |
7368a6c8 | 441 | |
e78a59f5 | 442 | compat_datafellows(remote_version); |
443 | ||
9a87e2ac | 444 | if (datafellows & SSH_BUG_PROBE) { |
bbe88b6d | 445 | logit("probed from %s with %s. Don't panic.", |
9a87e2ac | 446 | get_remote_ipaddr(), client_version_string); |
2362db19 | 447 | cleanup_exit(255); |
9a87e2ac | 448 | } |
449 | ||
3a1c54d4 | 450 | if (datafellows & SSH_BUG_SCANNER) { |
bbe88b6d | 451 | logit("scanned from %s with %s. Don't panic.", |
3a1c54d4 | 452 | get_remote_ipaddr(), client_version_string); |
2362db19 | 453 | cleanup_exit(255); |
3a1c54d4 | 454 | } |
455 | ||
a8be9f80 | 456 | mismatch = 0; |
6aacefa7 | 457 | switch (remote_major) { |
7368a6c8 | 458 | case 1: |
a306f2dd | 459 | if (remote_minor == 99) { |
460 | if (options.protocol & SSH_PROTO_2) | |
461 | enable_compat20(); | |
462 | else | |
463 | mismatch = 1; | |
464 | break; | |
465 | } | |
a8be9f80 | 466 | if (!(options.protocol & SSH_PROTO_1)) { |
467 | mismatch = 1; | |
468 | break; | |
469 | } | |
7368a6c8 | 470 | if (remote_minor < 3) { |
089fbbd2 | 471 | packet_disconnect("Your ssh version is too old and " |
7368a6c8 | 472 | "is no longer supported. Please install a newer version."); |
473 | } else if (remote_minor == 3) { | |
474 | /* note that this disables agent-forwarding */ | |
475 | enable_compat13(); | |
476 | } | |
a8be9f80 | 477 | break; |
e78a59f5 | 478 | case 2: |
a8be9f80 | 479 | if (options.protocol & SSH_PROTO_2) { |
e78a59f5 | 480 | enable_compat20(); |
481 | break; | |
482 | } | |
483 | /* FALLTHROUGH */ | |
6ae2364d | 484 | default: |
a8be9f80 | 485 | mismatch = 1; |
486 | break; | |
487 | } | |
488 | chop(server_version_string); | |
a8be9f80 | 489 | debug("Local version string %.200s", server_version_string); |
490 | ||
491 | if (mismatch) { | |
7368a6c8 | 492 | s = "Protocol major versions differ.\n"; |
dc54438a | 493 | (void) atomicio(vwrite, sock_out, s, strlen(s)); |
7368a6c8 | 494 | close(sock_in); |
495 | close(sock_out); | |
bbe88b6d | 496 | logit("Protocol major versions differ for %s: %.200s vs. %.200s", |
a8be9f80 | 497 | get_remote_ipaddr(), |
498 | server_version_string, client_version_string); | |
2362db19 | 499 | cleanup_exit(255); |
7368a6c8 | 500 | } |
a306f2dd | 501 | } |
502 | ||
fa08c86b | 503 | /* Destroy the host and server keys. They will no longer be needed. */ |
a306f2dd | 504 | void |
505 | destroy_sensitive_data(void) | |
506 | { | |
fa08c86b | 507 | int i; |
508 | ||
509 | if (sensitive_data.server_key) { | |
510 | key_free(sensitive_data.server_key); | |
511 | sensitive_data.server_key = NULL; | |
512 | } | |
184eed6a | 513 | for (i = 0; i < options.num_host_key_files; i++) { |
fa08c86b | 514 | if (sensitive_data.host_keys[i]) { |
515 | key_free(sensitive_data.host_keys[i]); | |
516 | sensitive_data.host_keys[i] = NULL; | |
517 | } | |
518 | } | |
519 | sensitive_data.ssh1_host_key = NULL; | |
00be5382 | 520 | memset(sensitive_data.ssh1_cookie, 0, SSH_SESSION_KEY_LENGTH); |
fa08c86b | 521 | } |
fa08c86b | 522 | |
1853d1ef | 523 | /* Demote private to public keys for network child */ |
524 | void | |
525 | demote_sensitive_data(void) | |
526 | { | |
527 | Key *tmp; | |
528 | int i; | |
529 | ||
530 | if (sensitive_data.server_key) { | |
531 | tmp = key_demote(sensitive_data.server_key); | |
532 | key_free(sensitive_data.server_key); | |
533 | sensitive_data.server_key = tmp; | |
534 | } | |
535 | ||
536 | for (i = 0; i < options.num_host_key_files; i++) { | |
537 | if (sensitive_data.host_keys[i]) { | |
538 | tmp = key_demote(sensitive_data.host_keys[i]); | |
539 | key_free(sensitive_data.host_keys[i]); | |
540 | sensitive_data.host_keys[i] = tmp; | |
541 | if (tmp->type == KEY_RSA1) | |
542 | sensitive_data.ssh1_host_key = tmp; | |
543 | } | |
544 | } | |
545 | ||
546 | /* We do not clear ssh1_host key and cookie. XXX - Okay Niels? */ | |
547 | } | |
548 | ||
51aeb639 | 549 | static void |
1853d1ef | 550 | privsep_preauth_child(void) |
551 | { | |
7fdc56c5 | 552 | u_int32_t rnd[256]; |
6ded293b | 553 | gid_t gidset[1]; |
2ea6de2b | 554 | struct passwd *pw; |
e424e241 | 555 | int i; |
1853d1ef | 556 | |
557 | /* Enable challenge-response authentication for privilege separation */ | |
558 | privsep_challenge_enable(); | |
559 | ||
560 | for (i = 0; i < 256; i++) | |
7fdc56c5 | 561 | rnd[i] = arc4random(); |
562 | RAND_seed(rnd, sizeof(rnd)); | |
1853d1ef | 563 | |
564 | /* Demote the private keys to public keys. */ | |
565 | demote_sensitive_data(); | |
566 | ||
2ea6de2b | 567 | if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) |
cdc4fc39 | 568 | fatal("Privilege separation user %s does not exist", |
569 | SSH_PRIVSEP_USER); | |
2ea6de2b | 570 | memset(pw->pw_passwd, 0, strlen(pw->pw_passwd)); |
571 | endpwent(); | |
572 | ||
343288b8 | 573 | /* Change our root directory */ |
1c352e97 | 574 | if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1) |
575 | fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR, | |
576 | strerror(errno)); | |
1853d1ef | 577 | if (chdir("/") == -1) |
edfb66cb | 578 | fatal("chdir(\"/\"): %s", strerror(errno)); |
762715ce | 579 | |
1853d1ef | 580 | /* Drop our privileges */ |
2ea6de2b | 581 | debug3("privsep user:group %u:%u", (u_int)pw->pw_uid, |
582 | (u_int)pw->pw_gid); | |
87809a1f | 583 | #if 0 |
6ff58a4b | 584 | /* XXX not ready, too heavy after chroot */ |
2ea6de2b | 585 | do_setusercontext(pw); |
87809a1f | 586 | #else |
587 | gidset[0] = pw->pw_gid; | |
87809a1f | 588 | if (setgroups(1, gidset) < 0) |
589 | fatal("setgroups: %.100s", strerror(errno)); | |
590 | permanently_set_uid(pw); | |
591 | #endif | |
1853d1ef | 592 | } |
593 | ||
2362db19 | 594 | static int |
595 | privsep_preauth(Authctxt *authctxt) | |
1853d1ef | 596 | { |
1853d1ef | 597 | int status; |
324bf712 | 598 | pid_t pid; |
1853d1ef | 599 | |
324bf712 | 600 | /* Set up unprivileged child process to deal with network data */ |
b5a28cbc | 601 | pmonitor = monitor_init(); |
324bf712 | 602 | /* Store a pointer to the kex for later rekeying */ |
b5a28cbc | 603 | pmonitor->m_pkex = &xxx_kex; |
324bf712 | 604 | |
605 | pid = fork(); | |
606 | if (pid == -1) { | |
607 | fatal("fork of unprivileged child failed"); | |
608 | } else if (pid != 0) { | |
c457707e | 609 | debug2("Network child is on pid %ld", (long)pid); |
324bf712 | 610 | |
b5a28cbc | 611 | close(pmonitor->m_recvfd); |
a9b33b95 | 612 | pmonitor->m_pid = pid; |
2362db19 | 613 | monitor_child_preauth(authctxt, pmonitor); |
b5a28cbc | 614 | close(pmonitor->m_sendfd); |
324bf712 | 615 | |
616 | /* Sync memory */ | |
b5a28cbc | 617 | monitor_sync(pmonitor); |
324bf712 | 618 | |
619 | /* Wait for the child's exit status */ | |
8c38e88b | 620 | while (waitpid(pid, &status, 0) < 0) |
621 | if (errno != EINTR) | |
622 | break; | |
2362db19 | 623 | return (1); |
324bf712 | 624 | } else { |
625 | /* child */ | |
626 | ||
b5a28cbc | 627 | close(pmonitor->m_sendfd); |
324bf712 | 628 | |
629 | /* Demote the child */ | |
630 | if (getuid() == 0 || geteuid() == 0) | |
631 | privsep_preauth_child(); | |
47c36e5b | 632 | setproctitle("%s", "[net]"); |
324bf712 | 633 | } |
2362db19 | 634 | return (0); |
324bf712 | 635 | } |
636 | ||
637 | static void | |
638 | privsep_postauth(Authctxt *authctxt) | |
639 | { | |
94d8258b | 640 | #ifdef DISABLE_FD_PASSING |
d170feb1 | 641 | if (1) { |
642 | #else | |
1853d1ef | 643 | if (authctxt->pw->pw_uid == 0 || options.use_login) { |
d170feb1 | 644 | #endif |
1853d1ef | 645 | /* File descriptor passing is broken or root login */ |
1853d1ef | 646 | use_privsep = 0; |
ae25711b | 647 | goto skip; |
1853d1ef | 648 | } |
762715ce | 649 | |
1853d1ef | 650 | /* New socket pair */ |
b5a28cbc | 651 | monitor_reinit(pmonitor); |
1853d1ef | 652 | |
b5a28cbc | 653 | pmonitor->m_pid = fork(); |
654 | if (pmonitor->m_pid == -1) | |
1853d1ef | 655 | fatal("fork of unprivileged child failed"); |
b5a28cbc | 656 | else if (pmonitor->m_pid != 0) { |
c457707e | 657 | debug2("User child is on pid %ld", (long)pmonitor->m_pid); |
b5a28cbc | 658 | close(pmonitor->m_recvfd); |
f143ed33 | 659 | buffer_clear(&loginmsg); |
b5a28cbc | 660 | monitor_child_postauth(pmonitor); |
1853d1ef | 661 | |
662 | /* NEVERREACHED */ | |
663 | exit(0); | |
664 | } | |
665 | ||
b5a28cbc | 666 | close(pmonitor->m_sendfd); |
1853d1ef | 667 | |
668 | /* Demote the private keys to public keys. */ | |
669 | demote_sensitive_data(); | |
670 | ||
671 | /* Drop privileges */ | |
672 | do_setusercontext(authctxt->pw); | |
673 | ||
ae25711b | 674 | skip: |
1853d1ef | 675 | /* It is safe now to apply the key state */ |
b5a28cbc | 676 | monitor_apply_keystate(pmonitor); |
07200973 | 677 | |
678 | /* | |
679 | * Tell the packet layer that authentication was successful, since | |
680 | * this information is not part of the key state. | |
681 | */ | |
682 | packet_set_authenticated(); | |
1853d1ef | 683 | } |
684 | ||
396c147e | 685 | static char * |
fa08c86b | 686 | list_hostkey_types(void) |
687 | { | |
3469eac4 | 688 | Buffer b; |
b6c7b7b7 | 689 | const char *p; |
690 | char *ret; | |
fa08c86b | 691 | int i; |
3469eac4 | 692 | |
693 | buffer_init(&b); | |
184eed6a | 694 | for (i = 0; i < options.num_host_key_files; i++) { |
fa08c86b | 695 | Key *key = sensitive_data.host_keys[i]; |
696 | if (key == NULL) | |
697 | continue; | |
6aacefa7 | 698 | switch (key->type) { |
fa08c86b | 699 | case KEY_RSA: |
700 | case KEY_DSA: | |
3469eac4 | 701 | if (buffer_len(&b) > 0) |
702 | buffer_append(&b, ",", 1); | |
703 | p = key_ssh_name(key); | |
704 | buffer_append(&b, p, strlen(p)); | |
fa08c86b | 705 | break; |
706 | } | |
707 | } | |
3469eac4 | 708 | buffer_append(&b, "\0", 1); |
b6c7b7b7 | 709 | ret = xstrdup(buffer_ptr(&b)); |
3469eac4 | 710 | buffer_free(&b); |
b6c7b7b7 | 711 | debug("list_hostkey_types: %s", ret); |
712 | return ret; | |
fa08c86b | 713 | } |
714 | ||
1853d1ef | 715 | Key * |
fa08c86b | 716 | get_hostkey_by_type(int type) |
717 | { | |
718 | int i; | |
e424e241 | 719 | |
184eed6a | 720 | for (i = 0; i < options.num_host_key_files; i++) { |
fa08c86b | 721 | Key *key = sensitive_data.host_keys[i]; |
722 | if (key != NULL && key->type == type) | |
723 | return key; | |
724 | } | |
725 | return NULL; | |
7368a6c8 | 726 | } |
727 | ||
1853d1ef | 728 | Key * |
729 | get_hostkey_by_index(int ind) | |
730 | { | |
731 | if (ind < 0 || ind >= options.num_host_key_files) | |
732 | return (NULL); | |
733 | return (sensitive_data.host_keys[ind]); | |
734 | } | |
735 | ||
736 | int | |
737 | get_hostkey_index(Key *key) | |
738 | { | |
739 | int i; | |
e424e241 | 740 | |
1853d1ef | 741 | for (i = 0; i < options.num_host_key_files; i++) { |
742 | if (key == sensitive_data.host_keys[i]) | |
743 | return (i); | |
744 | } | |
745 | return (-1); | |
746 | } | |
747 | ||
c345cf9d | 748 | /* |
749 | * returns 1 if connection should be dropped, 0 otherwise. | |
750 | * dropping starts at connection #max_startups_begin with a probability | |
751 | * of (max_startups_rate/100). the probability increases linearly until | |
752 | * all connections are dropped for startups > max_startups | |
753 | */ | |
396c147e | 754 | static int |
c345cf9d | 755 | drop_connection(int startups) |
756 | { | |
1c5eab6f | 757 | int p, r; |
c345cf9d | 758 | |
759 | if (startups < options.max_startups_begin) | |
760 | return 0; | |
761 | if (startups >= options.max_startups) | |
762 | return 1; | |
763 | if (options.max_startups_rate == 100) | |
764 | return 1; | |
765 | ||
766 | p = 100 - options.max_startups_rate; | |
767 | p *= startups - options.max_startups_begin; | |
1c5eab6f | 768 | p /= options.max_startups - options.max_startups_begin; |
c345cf9d | 769 | p += options.max_startups_rate; |
1c5eab6f | 770 | r = arc4random() % 100; |
c345cf9d | 771 | |
e9aec1d4 | 772 | debug("drop_connection: p %d, r %d", p, r); |
c345cf9d | 773 | return (r < p) ? 1 : 0; |
774 | } | |
775 | ||
2717fa0f | 776 | static void |
777 | usage(void) | |
778 | { | |
85ac7a84 | 779 | fprintf(stderr, "%s, %s\n", |
4526e8c2 | 780 | SSH_RELEASE, SSLeay_version(SSLEAY_VERSION)); |
65edde94 | 781 | fprintf(stderr, |
782 | "usage: sshd [-46Ddeiqt] [-b bits] [-f config_file] [-g login_grace_time]\n" | |
783 | " [-h host_key_file] [-k key_gen_time] [-o option] [-p port] [-u len]\n" | |
784 | ); | |
2717fa0f | 785 | exit(1); |
786 | } | |
787 | ||
b9a549d7 | 788 | static void |
789 | send_rexec_state(int fd, Buffer *conf) | |
790 | { | |
791 | Buffer m; | |
792 | ||
793 | debug3("%s: entering fd = %d config len %d", __func__, fd, | |
794 | buffer_len(conf)); | |
795 | ||
796 | /* | |
797 | * Protocol from reexec master to child: | |
798 | * string configuration | |
799 | * u_int ephemeral_key_follows | |
800 | * bignum e (only if ephemeral_key_follows == 1) | |
801 | * bignum n " | |
802 | * bignum d " | |
803 | * bignum iqmp " | |
804 | * bignum p " | |
805 | * bignum q " | |
72f02ae7 | 806 | * string rngseed (only if OpenSSL is not self-seeded) |
b9a549d7 | 807 | */ |
808 | buffer_init(&m); | |
809 | buffer_put_cstring(&m, buffer_ptr(conf)); | |
810 | ||
f2107e97 | 811 | if (sensitive_data.server_key != NULL && |
b9a549d7 | 812 | sensitive_data.server_key->type == KEY_RSA1) { |
813 | buffer_put_int(&m, 1); | |
814 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->e); | |
815 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->n); | |
816 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->d); | |
817 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->iqmp); | |
818 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->p); | |
819 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->q); | |
820 | } else | |
821 | buffer_put_int(&m, 0); | |
822 | ||
72f02ae7 | 823 | #ifndef OPENSSL_PRNG_ONLY |
824 | rexec_send_rng_seed(&m); | |
825 | #endif | |
826 | ||
b9a549d7 | 827 | if (ssh_msg_send(fd, 0, &m) == -1) |
828 | fatal("%s: ssh_msg_send failed", __func__); | |
829 | ||
830 | buffer_free(&m); | |
831 | ||
832 | debug3("%s: done", __func__); | |
833 | } | |
834 | ||
835 | static void | |
836 | recv_rexec_state(int fd, Buffer *conf) | |
837 | { | |
838 | Buffer m; | |
839 | char *cp; | |
840 | u_int len; | |
841 | ||
842 | debug3("%s: entering fd = %d", __func__, fd); | |
843 | ||
844 | buffer_init(&m); | |
845 | ||
846 | if (ssh_msg_recv(fd, &m) == -1) | |
847 | fatal("%s: ssh_msg_recv failed", __func__); | |
848 | if (buffer_get_char(&m) != 0) | |
849 | fatal("%s: rexec version mismatch", __func__); | |
850 | ||
851 | cp = buffer_get_string(&m, &len); | |
852 | if (conf != NULL) | |
853 | buffer_append(conf, cp, len + 1); | |
854 | xfree(cp); | |
855 | ||
856 | if (buffer_get_int(&m)) { | |
857 | if (sensitive_data.server_key != NULL) | |
858 | key_free(sensitive_data.server_key); | |
859 | sensitive_data.server_key = key_new_private(KEY_RSA1); | |
860 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->e); | |
861 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->n); | |
862 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->d); | |
863 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->iqmp); | |
864 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->p); | |
865 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->q); | |
866 | rsa_generate_additional_parameters( | |
867 | sensitive_data.server_key->rsa); | |
868 | } | |
72f02ae7 | 869 | |
870 | #ifndef OPENSSL_PRNG_ONLY | |
871 | rexec_recv_rng_seed(&m); | |
872 | #endif | |
873 | ||
b9a549d7 | 874 | buffer_free(&m); |
875 | ||
876 | debug3("%s: done", __func__); | |
877 | } | |
878 | ||
5260325f | 879 | /* |
880 | * Main program for the daemon. | |
881 | */ | |
8efc0c15 | 882 | int |
883 | main(int ac, char **av) | |
884 | { | |
5260325f | 885 | extern char *optarg; |
886 | extern int optind; | |
83529a6b | 887 | int opt, j, i, fdsetsz, on = 1; |
888 | int sock_in = -1, sock_out = -1, newsock = -1; | |
9da5c3c9 | 889 | pid_t pid; |
48e671d5 | 890 | socklen_t fromlen; |
48e671d5 | 891 | fd_set *fdset; |
892 | struct sockaddr_storage from; | |
5260325f | 893 | const char *remote_ip; |
894 | int remote_port; | |
5260325f | 895 | FILE *f; |
48e671d5 | 896 | struct addrinfo *ai; |
897 | char ntop[NI_MAXHOST], strport[NI_MAXSERV]; | |
c5894280 | 898 | char *line; |
48e671d5 | 899 | int listen_sock, maxfd; |
9216f89c | 900 | int startup_p[2] = { -1 , -1 }, config_s[2] = { -1 , -1 }; |
089fbbd2 | 901 | int startups = 0; |
aeaa3d9e | 902 | Key *key; |
2362db19 | 903 | Authctxt *authctxt; |
59c97189 | 904 | int ret, key_used = 0; |
b9a549d7 | 905 | Buffer cfg; |
5260325f | 906 | |
6e879cb4 | 907 | #ifdef HAVE_SECUREWARE |
908 | (void)set_auth_parameters(ac, av); | |
909 | #endif | |
fda04d7d | 910 | __progname = ssh_get_progname(av[0]); |
264dce47 | 911 | init_rng(); |
912 | ||
d0104542 | 913 | /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */ |
4d33e531 | 914 | saved_argc = ac; |
7706b4c7 | 915 | rexec_argc = ac; |
f420d2ba | 916 | saved_argv = xmalloc(sizeof(*saved_argv) * (ac + 1)); |
d0104542 | 917 | for (i = 0; i < ac; i++) |
918 | saved_argv[i] = xstrdup(av[i]); | |
f420d2ba | 919 | saved_argv[i] = NULL; |
d0104542 | 920 | |
921 | #ifndef HAVE_SETPROCTITLE | |
922 | /* Prepare for later setproctitle emulation */ | |
923 | compat_init_setproctitle(ac, av); | |
416c732d | 924 | av = saved_argv; |
d0104542 | 925 | #endif |
5260325f | 926 | |
a4c0faa2 | 927 | if (geteuid() == 0 && setgroups(0, NULL) == -1) |
928 | debug("setgroups(): %.200s", strerror(errno)); | |
929 | ||
fd6168c1 | 930 | /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ |
931 | sanitise_stdfd(); | |
932 | ||
5260325f | 933 | /* Initialize configuration options to their default values. */ |
934 | initialize_server_options(&options); | |
935 | ||
936 | /* Parse command-line arguments. */ | |
b9a549d7 | 937 | while ((opt = getopt(ac, av, "f:p:b:k:h:g:u:o:dDeiqrtQR46")) != -1) { |
5260325f | 938 | switch (opt) { |
48e671d5 | 939 | case '4': |
31b41ceb | 940 | options.address_family = AF_INET; |
48e671d5 | 941 | break; |
942 | case '6': | |
31b41ceb | 943 | options.address_family = AF_INET6; |
48e671d5 | 944 | break; |
5260325f | 945 | case 'f': |
946 | config_file_name = optarg; | |
947 | break; | |
948 | case 'd': | |
e053cd2c | 949 | if (debug_flag == 0) { |
bcbf86ec | 950 | debug_flag = 1; |
951 | options.log_level = SYSLOG_LEVEL_DEBUG1; | |
e053cd2c | 952 | } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) |
bcbf86ec | 953 | options.log_level++; |
5260325f | 954 | break; |
0b6fbf03 | 955 | case 'D': |
956 | no_daemon_flag = 1; | |
957 | break; | |
ff14faf1 | 958 | case 'e': |
959 | log_stderr = 1; | |
960 | break; | |
5260325f | 961 | case 'i': |
962 | inetd_flag = 1; | |
963 | break; | |
b9a549d7 | 964 | case 'r': |
965 | rexec_flag = 0; | |
966 | break; | |
967 | case 'R': | |
968 | rexeced_flag = 1; | |
969 | inetd_flag = 1; | |
970 | break; | |
5260325f | 971 | case 'Q': |
9bd5b720 | 972 | /* ignored */ |
5260325f | 973 | break; |
974 | case 'q': | |
975 | options.log_level = SYSLOG_LEVEL_QUIET; | |
976 | break; | |
977 | case 'b': | |
978 | options.server_key_bits = atoi(optarg); | |
979 | break; | |
980 | case 'p': | |
48e671d5 | 981 | options.ports_from_cmdline = 1; |
bcbf86ec | 982 | if (options.num_ports >= MAX_PORTS) { |
983 | fprintf(stderr, "too many ports.\n"); | |
984 | exit(1); | |
985 | } | |
2d2a2c65 | 986 | options.ports[options.num_ports++] = a2port(optarg); |
987 | if (options.ports[options.num_ports-1] == 0) { | |
988 | fprintf(stderr, "Bad port number.\n"); | |
989 | exit(1); | |
990 | } | |
5260325f | 991 | break; |
992 | case 'g': | |
e2b1fb42 | 993 | if ((options.login_grace_time = convtime(optarg)) == -1) { |
994 | fprintf(stderr, "Invalid login grace time.\n"); | |
995 | exit(1); | |
996 | } | |
5260325f | 997 | break; |
998 | case 'k': | |
e2b1fb42 | 999 | if ((options.key_regeneration_time = convtime(optarg)) == -1) { |
1000 | fprintf(stderr, "Invalid key regeneration interval.\n"); | |
1001 | exit(1); | |
1002 | } | |
5260325f | 1003 | break; |
1004 | case 'h': | |
fa08c86b | 1005 | if (options.num_host_key_files >= MAX_HOSTKEYS) { |
1006 | fprintf(stderr, "too many host keys.\n"); | |
1007 | exit(1); | |
1008 | } | |
1009 | options.host_key_files[options.num_host_key_files++] = optarg; | |
5260325f | 1010 | break; |
f87f09aa | 1011 | case 't': |
1012 | test_flag = 1; | |
1013 | break; | |
c345cf9d | 1014 | case 'u': |
1015 | utmp_len = atoi(optarg); | |
67f04db1 | 1016 | if (utmp_len > MAXHOSTNAMELEN) { |
1017 | fprintf(stderr, "Invalid utmp length.\n"); | |
1018 | exit(1); | |
1019 | } | |
c345cf9d | 1020 | break; |
2717fa0f | 1021 | case 'o': |
c5894280 | 1022 | line = xstrdup(optarg); |
1023 | if (process_server_config_line(&options, line, | |
2717fa0f | 1024 | "command-line", 0) != 0) |
184eed6a | 1025 | exit(1); |
c5894280 | 1026 | xfree(line); |
2717fa0f | 1027 | break; |
5260325f | 1028 | case '?': |
1029 | default: | |
2717fa0f | 1030 | usage(); |
1031 | break; | |
5260325f | 1032 | } |
1033 | } | |
b9a549d7 | 1034 | if (rexeced_flag || inetd_flag) |
1035 | rexec_flag = 0; | |
1036 | if (rexec_flag && (av[0] == NULL || *av[0] != '/')) | |
1037 | fatal("sshd re-exec requires execution with an absolute path"); | |
1038 | if (rexeced_flag) | |
b250e837 | 1039 | closefrom(REEXEC_MIN_FREE_FD); |
1040 | else | |
1041 | closefrom(REEXEC_DEVCRYPTO_RESERVED_FD); | |
b9a549d7 | 1042 | |
1a92bd7e | 1043 | SSLeay_add_all_algorithms(); |
5260325f | 1044 | |
48e671d5 | 1045 | /* |
1046 | * Force logging to stderr until we have loaded the private host | |
1047 | * key (unless started from inetd) | |
1048 | */ | |
1fe6a48f | 1049 | log_init(__progname, |
980c9344 | 1050 | options.log_level == SYSLOG_LEVEL_NOT_SET ? |
1051 | SYSLOG_LEVEL_INFO : options.log_level, | |
1052 | options.log_facility == SYSLOG_FACILITY_NOT_SET ? | |
1053 | SYSLOG_FACILITY_AUTH : options.log_facility, | |
51efad8c | 1054 | log_stderr || !inetd_flag); |
48e671d5 | 1055 | |
351f44a0 | 1056 | /* |
1057 | * Unset KRB5CCNAME, otherwise the user's session may inherit it from | |
1058 | * root's environment | |
d1cf9a87 | 1059 | */ |
3bfd27d5 | 1060 | if (getenv("KRB5CCNAME") != NULL) |
1061 | unsetenv("KRB5CCNAME"); | |
1062 | ||
ef51930f | 1063 | #ifdef _UNICOS |
e5ba4718 | 1064 | /* Cray can define user privs drop all privs now! |
1a23ac2c | 1065 | * Not needed on PRIV_SU systems! |
1066 | */ | |
1067 | drop_cray_privs(); | |
1068 | #endif | |
1069 | ||
b9a549d7 | 1070 | sensitive_data.server_key = NULL; |
1071 | sensitive_data.ssh1_host_key = NULL; | |
1072 | sensitive_data.have_ssh1_key = 0; | |
1073 | sensitive_data.have_ssh2_key = 0; | |
1074 | ||
1075 | /* Fetch our configuration */ | |
1076 | buffer_init(&cfg); | |
1077 | if (rexeced_flag) | |
b250e837 | 1078 | recv_rexec_state(REEXEC_CONFIG_PASS_FD, &cfg); |
b9a549d7 | 1079 | else |
1080 | load_server_config(config_file_name, &cfg); | |
1081 | ||
1082 | parse_server_config(&options, | |
1083 | rexeced_flag ? "rexec" : config_file_name, &cfg); | |
1084 | ||
1085 | if (!rexec_flag) | |
1086 | buffer_free(&cfg); | |
5260325f | 1087 | |
72f02ae7 | 1088 | seed_rng(); |
1089 | ||
5260325f | 1090 | /* Fill in default values for those options not explicitly set. */ |
1091 | fill_default_server_options(&options); | |
1092 | ||
31b41ceb | 1093 | /* set default channel AF */ |
1094 | channel_set_af(options.address_family); | |
1095 | ||
5260325f | 1096 | /* Check that there are no remaining arguments. */ |
1097 | if (optind < ac) { | |
1098 | fprintf(stderr, "Extra argument %s.\n", av[optind]); | |
1099 | exit(1); | |
8efc0c15 | 1100 | } |
5260325f | 1101 | |
4526e8c2 | 1102 | debug("sshd version %.100s", SSH_RELEASE); |
5260325f | 1103 | |
fa08c86b | 1104 | /* load private host keys */ |
343288b8 | 1105 | sensitive_data.host_keys = xmalloc(options.num_host_key_files * |
1106 | sizeof(Key *)); | |
184eed6a | 1107 | for (i = 0; i < options.num_host_key_files; i++) |
1e3b8b07 | 1108 | sensitive_data.host_keys[i] = NULL; |
a306f2dd | 1109 | |
184eed6a | 1110 | for (i = 0; i < options.num_host_key_files; i++) { |
aeaa3d9e | 1111 | key = key_load_private(options.host_key_files[i], "", NULL); |
1112 | sensitive_data.host_keys[i] = key; | |
fa08c86b | 1113 | if (key == NULL) { |
58cfa257 | 1114 | error("Could not load host key: %s", |
1115 | options.host_key_files[i]); | |
aeaa3d9e | 1116 | sensitive_data.host_keys[i] = NULL; |
fa08c86b | 1117 | continue; |
a306f2dd | 1118 | } |
6aacefa7 | 1119 | switch (key->type) { |
fa08c86b | 1120 | case KEY_RSA1: |
1121 | sensitive_data.ssh1_host_key = key; | |
1122 | sensitive_data.have_ssh1_key = 1; | |
1123 | break; | |
1124 | case KEY_RSA: | |
1125 | case KEY_DSA: | |
1126 | sensitive_data.have_ssh2_key = 1; | |
1127 | break; | |
a306f2dd | 1128 | } |
aeaa3d9e | 1129 | debug("private host key: #%d type %d %s", i, key->type, |
1130 | key_type(key)); | |
fa08c86b | 1131 | } |
1132 | if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) { | |
bbe88b6d | 1133 | logit("Disabling protocol version 1. Could not load host key"); |
fa08c86b | 1134 | options.protocol &= ~SSH_PROTO_1; |
1135 | } | |
1136 | if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) { | |
bbe88b6d | 1137 | logit("Disabling protocol version 2. Could not load host key"); |
fa08c86b | 1138 | options.protocol &= ~SSH_PROTO_2; |
a306f2dd | 1139 | } |
6a416424 | 1140 | if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) { |
bbe88b6d | 1141 | logit("sshd: no hostkeys available -- exiting."); |
5260325f | 1142 | exit(1); |
1143 | } | |
5260325f | 1144 | |
a306f2dd | 1145 | /* Check certain values for sanity. */ |
1146 | if (options.protocol & SSH_PROTO_1) { | |
1147 | if (options.server_key_bits < 512 || | |
1148 | options.server_key_bits > 32768) { | |
1149 | fprintf(stderr, "Bad server key size.\n"); | |
1150 | exit(1); | |
1151 | } | |
1152 | /* | |
1153 | * Check that server and host key lengths differ sufficiently. This | |
1154 | * is necessary to make double encryption work with rsaref. Oh, I | |
1155 | * hate software patents. I dont know if this can go? Niels | |
1156 | */ | |
1157 | if (options.server_key_bits > | |
e424e241 | 1158 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) - |
1159 | SSH_KEY_BITS_RESERVED && options.server_key_bits < | |
1160 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + | |
1161 | SSH_KEY_BITS_RESERVED) { | |
a306f2dd | 1162 | options.server_key_bits = |
e424e241 | 1163 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + |
1164 | SSH_KEY_BITS_RESERVED; | |
a306f2dd | 1165 | debug("Forcing server key to %d bits to make it differ from host key.", |
1166 | options.server_key_bits); | |
1167 | } | |
1168 | } | |
1169 | ||
3cc54fbb | 1170 | if (use_privsep) { |
1171 | struct passwd *pw; | |
1172 | struct stat st; | |
1173 | ||
1174 | if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) | |
1175 | fatal("Privilege separation user %s does not exist", | |
1176 | SSH_PRIVSEP_USER); | |
1177 | if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) || | |
1178 | (S_ISDIR(st.st_mode) == 0)) | |
1179 | fatal("Missing privilege separation directory: %s", | |
1180 | _PATH_PRIVSEP_CHROOT_DIR); | |
b9b82dab | 1181 | |
1182 | #ifdef HAVE_CYGWIN | |
1183 | if (check_ntsec(_PATH_PRIVSEP_CHROOT_DIR) && | |
1184 | (st.st_uid != getuid () || | |
1185 | (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)) | |
1186 | #else | |
a56313d7 | 1187 | if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0) |
b9b82dab | 1188 | #endif |
5f021474 | 1189 | fatal("%s must be owned by root and not group or " |
1190 | "world-writable.", _PATH_PRIVSEP_CHROOT_DIR); | |
3cc54fbb | 1191 | } |
1192 | ||
f87f09aa | 1193 | /* Configuration looks good, so exit if in test mode. */ |
1194 | if (test_flag) | |
1195 | exit(0); | |
1196 | ||
018a5ea3 | 1197 | /* |
1198 | * Clear out any supplemental groups we may have inherited. This | |
1199 | * prevents inadvertent creation of files with bad modes (in the | |
aff51935 | 1200 | * portable version at least, it's certainly possible for PAM |
1201 | * to create a file, and we can't control the code in every | |
018a5ea3 | 1202 | * module which might be used). |
1203 | */ | |
1204 | if (setgroups(0, NULL) < 0) | |
1205 | debug("setgroups() failed: %.200s", strerror(errno)); | |
1206 | ||
b9a549d7 | 1207 | if (rexec_flag) { |
1208 | rexec_argv = xmalloc(sizeof(char *) * (rexec_argc + 2)); | |
1209 | for (i = 0; i < rexec_argc; i++) { | |
1210 | debug("rexec_argv[%d]='%s'", i, saved_argv[i]); | |
1211 | rexec_argv[i] = saved_argv[i]; | |
1212 | } | |
1213 | rexec_argv[rexec_argc] = "-R"; | |
1214 | rexec_argv[rexec_argc + 1] = NULL; | |
1215 | } | |
1216 | ||
a306f2dd | 1217 | /* Initialize the log (it is reinitialized below in case we forked). */ |
25c31d49 | 1218 | if (debug_flag && (!inetd_flag || rexeced_flag)) |
5260325f | 1219 | log_stderr = 1; |
1fe6a48f | 1220 | log_init(__progname, options.log_level, options.log_facility, log_stderr); |
5260325f | 1221 | |
a306f2dd | 1222 | /* |
1223 | * If not in debugging mode, and not started from inetd, disconnect | |
1224 | * from the controlling terminal, and fork. The original process | |
1225 | * exits. | |
1226 | */ | |
0b6fbf03 | 1227 | if (!(debug_flag || inetd_flag || no_daemon_flag)) { |
8efc0c15 | 1228 | #ifdef TIOCNOTTY |
5260325f | 1229 | int fd; |
8efc0c15 | 1230 | #endif /* TIOCNOTTY */ |
5260325f | 1231 | if (daemon(0, 0) < 0) |
1232 | fatal("daemon() failed: %.200s", strerror(errno)); | |
1233 | ||
1234 | /* Disconnect from the controlling tty. */ | |
8efc0c15 | 1235 | #ifdef TIOCNOTTY |
5ca51e19 | 1236 | fd = open(_PATH_TTY, O_RDWR | O_NOCTTY); |
5260325f | 1237 | if (fd >= 0) { |
1238 | (void) ioctl(fd, TIOCNOTTY, NULL); | |
1239 | close(fd); | |
1240 | } | |
8efc0c15 | 1241 | #endif /* TIOCNOTTY */ |
8efc0c15 | 1242 | } |
5260325f | 1243 | /* Reinitialize the log (because of the fork above). */ |
1fe6a48f | 1244 | log_init(__progname, options.log_level, options.log_facility, log_stderr); |
5260325f | 1245 | |
5260325f | 1246 | /* Initialize the random number generator. */ |
1247 | arc4random_stir(); | |
1248 | ||
1249 | /* Chdir to the root directory so that the current disk can be | |
1250 | unmounted if desired. */ | |
1251 | chdir("/"); | |
184eed6a | 1252 | |
1d3c30db | 1253 | /* ignore SIGPIPE */ |
1254 | signal(SIGPIPE, SIG_IGN); | |
5260325f | 1255 | |
5260325f | 1256 | /* Start listening for a socket, unless started from inetd. */ |
1257 | if (inetd_flag) { | |
b9a549d7 | 1258 | int fd; |
1259 | ||
4c8722d9 | 1260 | startup_pipe = -1; |
b9a549d7 | 1261 | if (rexeced_flag) { |
b250e837 | 1262 | close(REEXEC_CONFIG_PASS_FD); |
b9a549d7 | 1263 | sock_in = sock_out = dup(STDIN_FILENO); |
1264 | if (!debug_flag) { | |
b250e837 | 1265 | startup_pipe = dup(REEXEC_STARTUP_PIPE_FD); |
1266 | close(REEXEC_STARTUP_PIPE_FD); | |
b9a549d7 | 1267 | } |
1268 | } else { | |
1269 | sock_in = dup(STDIN_FILENO); | |
1270 | sock_out = dup(STDOUT_FILENO); | |
1271 | } | |
a306f2dd | 1272 | /* |
1273 | * We intentionally do not close the descriptors 0, 1, and 2 | |
b9a549d7 | 1274 | * as our code for setting the descriptors won't work if |
a306f2dd | 1275 | * ttyfd happens to be one of those. |
1276 | */ | |
b9a549d7 | 1277 | if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { |
1278 | dup2(fd, STDIN_FILENO); | |
1279 | dup2(fd, STDOUT_FILENO); | |
1280 | if (fd > STDOUT_FILENO) | |
1281 | close(fd); | |
1282 | } | |
5260325f | 1283 | debug("inetd sockets after dupping: %d, %d", sock_in, sock_out); |
b9a549d7 | 1284 | if ((options.protocol & SSH_PROTO_1) && |
1285 | sensitive_data.server_key == NULL) | |
cb7bd922 | 1286 | generate_ephemeral_server_key(); |
5260325f | 1287 | } else { |
48e671d5 | 1288 | for (ai = options.listen_addrs; ai; ai = ai->ai_next) { |
1289 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) | |
1290 | continue; | |
1291 | if (num_listen_socks >= MAX_LISTEN_SOCKS) | |
1292 | fatal("Too many listen sockets. " | |
1293 | "Enlarge MAX_LISTEN_SOCKS"); | |
945a9853 | 1294 | if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen, |
48e671d5 | 1295 | ntop, sizeof(ntop), strport, sizeof(strport), |
945a9853 | 1296 | NI_NUMERICHOST|NI_NUMERICSERV)) != 0) { |
1297 | error("getnameinfo failed: %.100s", | |
1298 | (ret != EAI_SYSTEM) ? gai_strerror(ret) : | |
1299 | strerror(errno)); | |
48e671d5 | 1300 | continue; |
1301 | } | |
1302 | /* Create socket for listening. */ | |
3e131a6d | 1303 | listen_sock = socket(ai->ai_family, ai->ai_socktype, |
1304 | ai->ai_protocol); | |
48e671d5 | 1305 | if (listen_sock < 0) { |
1306 | /* kernel may not support ipv6 */ | |
1307 | verbose("socket: %.100s", strerror(errno)); | |
1308 | continue; | |
1309 | } | |
170694d7 | 1310 | if (set_nonblock(listen_sock) == -1) { |
a666e3b1 | 1311 | close(listen_sock); |
1312 | continue; | |
1313 | } | |
48e671d5 | 1314 | /* |
facfd613 | 1315 | * Set socket options. |
1316 | * Allow local port reuse in TIME_WAIT. | |
48e671d5 | 1317 | */ |
facfd613 | 1318 | if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR, |
1319 | &on, sizeof(on)) == -1) | |
1320 | error("setsockopt SO_REUSEADDR: %s", strerror(errno)); | |
48e671d5 | 1321 | |
1322 | debug("Bind to port %s on %s.", strport, ntop); | |
1323 | ||
1324 | /* Bind the socket to the desired port. */ | |
32ced054 | 1325 | if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) { |
1326 | if (!ai->ai_next) | |
1327 | error("Bind to port %s on %s failed: %.200s.", | |
1328 | strport, ntop, strerror(errno)); | |
48e671d5 | 1329 | close(listen_sock); |
1330 | continue; | |
1331 | } | |
1332 | listen_socks[num_listen_socks] = listen_sock; | |
1333 | num_listen_socks++; | |
1334 | ||
1335 | /* Start listening on the port. */ | |
fce39749 | 1336 | if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0) |
9f513268 | 1337 | fatal("listen on [%s]:%s: %.100s", |
1338 | ntop, strport, strerror(errno)); | |
1339 | logit("Server listening on %s port %s.", ntop, strport); | |
5260325f | 1340 | } |
48e671d5 | 1341 | freeaddrinfo(options.listen_addrs); |
1342 | ||
1343 | if (!num_listen_socks) | |
1344 | fatal("Cannot bind any address."); | |
1345 | ||
3aca00a3 | 1346 | if (options.protocol & SSH_PROTO_1) |
1347 | generate_ephemeral_server_key(); | |
1348 | ||
1349 | /* | |
1350 | * Arrange to restart on SIGHUP. The handler needs | |
1351 | * listen_sock. | |
1352 | */ | |
1353 | signal(SIGHUP, sighup_handler); | |
1354 | ||
1355 | signal(SIGTERM, sigterm_handler); | |
1356 | signal(SIGQUIT, sigterm_handler); | |
1357 | ||
1358 | /* Arrange SIGCHLD to be caught. */ | |
1359 | signal(SIGCHLD, main_sigchld_handler); | |
1360 | ||
1361 | /* Write out the pid file after the sigterm handler is setup */ | |
5260325f | 1362 | if (!debug_flag) { |
aa3378df | 1363 | /* |
97fb6912 | 1364 | * Record our pid in /var/run/sshd.pid to make it |
1365 | * easier to kill the correct sshd. We don't want to | |
1366 | * do this before the bind above because the bind will | |
aa3378df | 1367 | * fail if there already is a daemon, and this will |
1368 | * overwrite any old pid in the file. | |
1369 | */ | |
3c62e7eb | 1370 | f = fopen(options.pid_file, "wb"); |
71b9ced0 | 1371 | if (f == NULL) { |
1372 | error("Couldn't create pid file \"%s\": %s", | |
1373 | options.pid_file, strerror(errno)); | |
1374 | } else { | |
c457707e | 1375 | fprintf(f, "%ld\n", (long) getpid()); |
5260325f | 1376 | fclose(f); |
1377 | } | |
8efc0c15 | 1378 | } |
5260325f | 1379 | |
48e671d5 | 1380 | /* setup fd set for listen */ |
089fbbd2 | 1381 | fdset = NULL; |
48e671d5 | 1382 | maxfd = 0; |
1383 | for (i = 0; i < num_listen_socks; i++) | |
1384 | if (listen_socks[i] > maxfd) | |
1385 | maxfd = listen_socks[i]; | |
089fbbd2 | 1386 | /* pipes connected to unauthenticated childs */ |
1387 | startup_pipes = xmalloc(options.max_startups * sizeof(int)); | |
1388 | for (i = 0; i < options.max_startups; i++) | |
1389 | startup_pipes[i] = -1; | |
48e671d5 | 1390 | |
aa3378df | 1391 | /* |
1392 | * Stay listening for connections until the system crashes or | |
1393 | * the daemon is killed with a signal. | |
1394 | */ | |
5260325f | 1395 | for (;;) { |
1396 | if (received_sighup) | |
1397 | sighup_restart(); | |
089fbbd2 | 1398 | if (fdset != NULL) |
1399 | xfree(fdset); | |
b5c334cc | 1400 | fdsetsz = howmany(maxfd+1, NFDBITS) * sizeof(fd_mask); |
089fbbd2 | 1401 | fdset = (fd_set *)xmalloc(fdsetsz); |
48e671d5 | 1402 | memset(fdset, 0, fdsetsz); |
089fbbd2 | 1403 | |
48e671d5 | 1404 | for (i = 0; i < num_listen_socks; i++) |
1405 | FD_SET(listen_socks[i], fdset); | |
089fbbd2 | 1406 | for (i = 0; i < options.max_startups; i++) |
1407 | if (startup_pipes[i] != -1) | |
1408 | FD_SET(startup_pipes[i], fdset); | |
1409 | ||
1410 | /* Wait in select until there is a connection. */ | |
59c97189 | 1411 | ret = select(maxfd+1, fdset, NULL, NULL, NULL); |
1412 | if (ret < 0 && errno != EINTR) | |
1413 | error("select: %.100s", strerror(errno)); | |
c9130033 | 1414 | if (received_sigterm) { |
bbe88b6d | 1415 | logit("Received signal %d; terminating.", |
010f9726 | 1416 | (int) received_sigterm); |
c9130033 | 1417 | close_listen_socks(); |
1418 | unlink(options.pid_file); | |
1419 | exit(255); | |
1420 | } | |
59c97189 | 1421 | if (key_used && key_do_regen) { |
cb7bd922 | 1422 | generate_ephemeral_server_key(); |
59c97189 | 1423 | key_used = 0; |
1424 | key_do_regen = 0; | |
48e671d5 | 1425 | } |
59c97189 | 1426 | if (ret < 0) |
1427 | continue; | |
1428 | ||
089fbbd2 | 1429 | for (i = 0; i < options.max_startups; i++) |
1430 | if (startup_pipes[i] != -1 && | |
1431 | FD_ISSET(startup_pipes[i], fdset)) { | |
1432 | /* | |
1433 | * the read end of the pipe is ready | |
1434 | * if the child has closed the pipe | |
8abcdba4 | 1435 | * after successful authentication |
089fbbd2 | 1436 | * or if the child has died |
1437 | */ | |
1438 | close(startup_pipes[i]); | |
1439 | startup_pipes[i] = -1; | |
1440 | startups--; | |
1441 | } | |
48e671d5 | 1442 | for (i = 0; i < num_listen_socks; i++) { |
1443 | if (!FD_ISSET(listen_socks[i], fdset)) | |
5260325f | 1444 | continue; |
089fbbd2 | 1445 | fromlen = sizeof(from); |
1446 | newsock = accept(listen_socks[i], (struct sockaddr *)&from, | |
1447 | &fromlen); | |
1448 | if (newsock < 0) { | |
1449 | if (errno != EINTR && errno != EWOULDBLOCK) | |
1450 | error("accept: %.100s", strerror(errno)); | |
1451 | continue; | |
1452 | } | |
170694d7 | 1453 | if (unset_nonblock(newsock) == -1) { |
a666e3b1 | 1454 | close(newsock); |
1455 | continue; | |
1456 | } | |
c345cf9d | 1457 | if (drop_connection(startups) == 1) { |
1458 | debug("drop connection #%d", startups); | |
089fbbd2 | 1459 | close(newsock); |
1460 | continue; | |
1461 | } | |
1462 | if (pipe(startup_p) == -1) { | |
1463 | close(newsock); | |
1464 | continue; | |
1465 | } | |
1466 | ||
b9a549d7 | 1467 | if (rexec_flag && socketpair(AF_UNIX, |
1468 | SOCK_STREAM, 0, config_s) == -1) { | |
1469 | error("reexec socketpair: %s", | |
1470 | strerror(errno)); | |
1471 | close(newsock); | |
1472 | close(startup_p[0]); | |
1473 | close(startup_p[1]); | |
1474 | continue; | |
1475 | } | |
1476 | ||
089fbbd2 | 1477 | for (j = 0; j < options.max_startups; j++) |
1478 | if (startup_pipes[j] == -1) { | |
1479 | startup_pipes[j] = startup_p[0]; | |
1480 | if (maxfd < startup_p[0]) | |
1481 | maxfd = startup_p[0]; | |
1482 | startups++; | |
1483 | break; | |
1484 | } | |
2b87da3b | 1485 | |
aa3378df | 1486 | /* |
089fbbd2 | 1487 | * Got connection. Fork a child to handle it, unless |
1488 | * we are in debugging mode. | |
aa3378df | 1489 | */ |
089fbbd2 | 1490 | if (debug_flag) { |
aa3378df | 1491 | /* |
089fbbd2 | 1492 | * In debugging mode. Close the listening |
1493 | * socket, and start processing the | |
1494 | * connection without forking. | |
aa3378df | 1495 | */ |
089fbbd2 | 1496 | debug("Server will not fork when running in debugging mode."); |
48e671d5 | 1497 | close_listen_socks(); |
5260325f | 1498 | sock_in = newsock; |
1499 | sock_out = newsock; | |
b9a549d7 | 1500 | close(startup_p[0]); |
1501 | close(startup_p[1]); | |
5540ea9b | 1502 | startup_pipe = -1; |
3f7a7e4a | 1503 | pid = getpid(); |
b9a549d7 | 1504 | if (rexec_flag) { |
1505 | send_rexec_state(config_s[0], | |
1506 | &cfg); | |
1507 | close(config_s[0]); | |
1508 | } | |
5260325f | 1509 | break; |
089fbbd2 | 1510 | } else { |
1511 | /* | |
1512 | * Normal production daemon. Fork, and have | |
1513 | * the child process the connection. The | |
1514 | * parent continues listening. | |
1515 | */ | |
1516 | if ((pid = fork()) == 0) { | |
1517 | /* | |
1518 | * Child. Close the listening and max_startup | |
1519 | * sockets. Start using the accepted socket. | |
1520 | * Reinitialize logging (since our pid has | |
1521 | * changed). We break out of the loop to handle | |
1522 | * the connection. | |
1523 | */ | |
1524 | startup_pipe = startup_p[1]; | |
7ace8c3b | 1525 | close_startup_pipes(); |
089fbbd2 | 1526 | close_listen_socks(); |
1527 | sock_in = newsock; | |
1528 | sock_out = newsock; | |
1fe6a48f | 1529 | log_init(__progname, options.log_level, options.log_facility, log_stderr); |
9216f89c | 1530 | if (rexec_flag) |
1531 | close(config_s[0]); | |
089fbbd2 | 1532 | break; |
1533 | } | |
5260325f | 1534 | } |
5260325f | 1535 | |
089fbbd2 | 1536 | /* Parent. Stay in the loop. */ |
1537 | if (pid < 0) | |
1538 | error("fork: %.100s", strerror(errno)); | |
1539 | else | |
c457707e | 1540 | debug("Forked child %ld.", (long)pid); |
5260325f | 1541 | |
089fbbd2 | 1542 | close(startup_p[1]); |
5260325f | 1543 | |
b9a549d7 | 1544 | if (rexec_flag) { |
1545 | send_rexec_state(config_s[0], &cfg); | |
1546 | close(config_s[0]); | |
1547 | close(config_s[1]); | |
1548 | } | |
1549 | ||
089fbbd2 | 1550 | /* Mark that the key has been used (it was "given" to the child). */ |
59c97189 | 1551 | if ((options.protocol & SSH_PROTO_1) && |
1552 | key_used == 0) { | |
1553 | /* Schedule server key regeneration alarm. */ | |
f00d1f78 | 1554 | signal(SIGALRM, key_regeneration_alarm); |
59c97189 | 1555 | alarm(options.key_regeneration_time); |
1556 | key_used = 1; | |
1557 | } | |
5260325f | 1558 | |
089fbbd2 | 1559 | arc4random_stir(); |
1560 | ||
1561 | /* Close the new socket (the child is now taking care of it). */ | |
1562 | close(newsock); | |
1563 | } | |
48e671d5 | 1564 | /* child process check (or debug mode) */ |
1565 | if (num_listen_socks < 0) | |
1566 | break; | |
5260325f | 1567 | } |
1568 | } | |
8efc0c15 | 1569 | |
5260325f | 1570 | /* This is the child processing a new connection. */ |
cc120685 | 1571 | setproctitle("%s", "[accepted]"); |
5260325f | 1572 | |
8b758bd2 | 1573 | /* |
1574 | * Create a new session and process group since the 4.4BSD | |
1575 | * setlogin() affects the entire process group. We don't | |
1576 | * want the child to be able to affect the parent. | |
1577 | */ | |
1578 | #if !defined(SSHD_ACQUIRES_CTTY) | |
1579 | /* | |
1580 | * If setsid is called, on some platforms sshd will later acquire a | |
1581 | * controlling terminal which will result in "could not set | |
1582 | * controlling tty" errors. | |
1583 | */ | |
1584 | if (!debug_flag && !inetd_flag && setsid() < 0) | |
1585 | error("setsid: %.100s", strerror(errno)); | |
1586 | #endif | |
1587 | ||
b9a549d7 | 1588 | if (rexec_flag) { |
1589 | int fd; | |
1590 | ||
b250e837 | 1591 | debug("rexec start in %d out %d newsock %d pipe %d sock %d", |
1592 | sock_in, sock_out, newsock, startup_pipe, config_s[0]); | |
b9a549d7 | 1593 | dup2(newsock, STDIN_FILENO); |
1594 | dup2(STDIN_FILENO, STDOUT_FILENO); | |
1595 | if (startup_pipe == -1) | |
b250e837 | 1596 | close(REEXEC_STARTUP_PIPE_FD); |
b9a549d7 | 1597 | else |
b250e837 | 1598 | dup2(startup_pipe, REEXEC_STARTUP_PIPE_FD); |
b9a549d7 | 1599 | |
b250e837 | 1600 | dup2(config_s[1], REEXEC_CONFIG_PASS_FD); |
b9a549d7 | 1601 | close(config_s[1]); |
ad148c04 | 1602 | if (startup_pipe != -1) |
1603 | close(startup_pipe); | |
b250e837 | 1604 | |
b9a549d7 | 1605 | execv(rexec_argv[0], rexec_argv); |
1606 | ||
1607 | /* Reexec has failed, fall back and continue */ | |
1608 | error("rexec of %s failed: %s", rexec_argv[0], strerror(errno)); | |
b250e837 | 1609 | recv_rexec_state(REEXEC_CONFIG_PASS_FD, NULL); |
b9a549d7 | 1610 | log_init(__progname, options.log_level, |
1611 | options.log_facility, log_stderr); | |
1612 | ||
1613 | /* Clean up fds */ | |
b250e837 | 1614 | startup_pipe = REEXEC_STARTUP_PIPE_FD; |
b9a549d7 | 1615 | close(config_s[1]); |
b250e837 | 1616 | close(REEXEC_CONFIG_PASS_FD); |
1617 | newsock = sock_out = sock_in = dup(STDIN_FILENO); | |
b9a549d7 | 1618 | if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { |
1619 | dup2(fd, STDIN_FILENO); | |
1620 | dup2(fd, STDOUT_FILENO); | |
1621 | if (fd > STDERR_FILENO) | |
1622 | close(fd); | |
1623 | } | |
b250e837 | 1624 | debug("rexec cleanup in %d out %d newsock %d pipe %d sock %d", |
1625 | sock_in, sock_out, newsock, startup_pipe, config_s[0]); | |
b9a549d7 | 1626 | } |
1627 | ||
aa3378df | 1628 | /* |
1629 | * Disable the key regeneration alarm. We will not regenerate the | |
1630 | * key since we are no longer in a position to give it to anyone. We | |
1631 | * will not restart on SIGHUP since it no longer makes sense. | |
1632 | */ | |
5260325f | 1633 | alarm(0); |
1634 | signal(SIGALRM, SIG_DFL); | |
1635 | signal(SIGHUP, SIG_DFL); | |
1636 | signal(SIGTERM, SIG_DFL); | |
1637 | signal(SIGQUIT, SIG_DFL); | |
1638 | signal(SIGCHLD, SIG_DFL); | |
9aaf9be4 | 1639 | signal(SIGINT, SIG_DFL); |
5260325f | 1640 | |
aa3378df | 1641 | /* |
1642 | * Register our connection. This turns encryption off because we do | |
1643 | * not have a key. | |
1644 | */ | |
5260325f | 1645 | packet_set_connection(sock_in, sock_out); |
07200973 | 1646 | packet_set_server(); |
5260325f | 1647 | |
7c3bc5a2 | 1648 | /* Set SO_KEEPALIVE if requested. */ |
1649 | if (options.tcp_keep_alive && packet_connection_is_on_socket() && | |
1650 | setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) < 0) | |
1651 | error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); | |
1652 | ||
29798ed0 | 1653 | if ((remote_port = get_remote_port()) < 0) { |
1654 | debug("get_remote_port failed"); | |
1655 | cleanup_exit(255); | |
1656 | } | |
3a85986d | 1657 | |
1658 | /* | |
1659 | * We use get_canonical_hostname with usedns = 0 instead of | |
1660 | * get_remote_ipaddr here so IP options will be checked. | |
1661 | */ | |
1662 | remote_ip = get_canonical_hostname(0); | |
5260325f | 1663 | |
6039eeef | 1664 | #ifdef SSH_AUDIT_EVENTS |
c00e4d75 | 1665 | audit_connection_from(remote_ip, remote_port); |
1666 | #endif | |
5260325f | 1667 | #ifdef LIBWRAP |
ac28afd8 | 1668 | /* Check whether logins are denied from this host. */ |
33e5359c | 1669 | if (packet_connection_is_on_socket()) { |
5260325f | 1670 | struct request_info req; |
8efc0c15 | 1671 | |
8fbc356d | 1672 | request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0); |
5260325f | 1673 | fromhost(&req); |
8efc0c15 | 1674 | |
5260325f | 1675 | if (!hosts_access(&req)) { |
ac28afd8 | 1676 | debug("Connection refused by tcp wrapper"); |
563834bb | 1677 | refuse(&req); |
ac28afd8 | 1678 | /* NOTREACHED */ |
1679 | fatal("libwrap refuse returns"); | |
5260325f | 1680 | } |
8efc0c15 | 1681 | } |
48e671d5 | 1682 | #endif /* LIBWRAP */ |
ac28afd8 | 1683 | |
5260325f | 1684 | /* Log the connection. */ |
1685 | verbose("Connection from %.500s port %d", remote_ip, remote_port); | |
8efc0c15 | 1686 | |
aa3378df | 1687 | /* |
7b9b0103 | 1688 | * We don't want to listen forever unless the other side |
aa3378df | 1689 | * successfully authenticates itself. So we set up an alarm which is |
1690 | * cleared after successful authentication. A limit of zero | |
7b9b0103 | 1691 | * indicates no limit. Note that we don't set the alarm in debugging |
aa3378df | 1692 | * mode; it is just annoying to have the server exit just when you |
1693 | * are about to discover the bug. | |
1694 | */ | |
f00d1f78 | 1695 | signal(SIGALRM, grace_alarm_handler); |
5260325f | 1696 | if (!debug_flag) |
1697 | alarm(options.login_grace_time); | |
1698 | ||
7368a6c8 | 1699 | sshd_exchange_identification(sock_in, sock_out); |
0598d99d | 1700 | |
5260325f | 1701 | packet_set_nonblocking(); |
1702 | ||
2362db19 | 1703 | /* allocate authentication context */ |
1704 | authctxt = xmalloc(sizeof(*authctxt)); | |
1705 | memset(authctxt, 0, sizeof(*authctxt)); | |
1706 | ||
1b394137 | 1707 | authctxt->loginmsg = &loginmsg; |
1708 | ||
2362db19 | 1709 | /* XXX global for cleanup, access from other modules */ |
1710 | the_authctxt = authctxt; | |
1711 | ||
022487ce | 1712 | /* prepare buffer to collect messages to display to user after login */ |
1713 | buffer_init(&loginmsg); | |
1714 | ||
324bf712 | 1715 | if (use_privsep) |
2362db19 | 1716 | if (privsep_preauth(authctxt) == 1) |
324bf712 | 1717 | goto authenticated; |
1853d1ef | 1718 | |
7b2ea3a1 | 1719 | /* perform the key exchange */ |
7b2ea3a1 | 1720 | /* authenticate user and start session */ |
e78a59f5 | 1721 | if (compat20) { |
1722 | do_ssh2_kex(); | |
2362db19 | 1723 | do_authentication2(authctxt); |
e78a59f5 | 1724 | } else { |
1725 | do_ssh1_kex(); | |
2362db19 | 1726 | do_authentication(authctxt); |
e78a59f5 | 1727 | } |
324bf712 | 1728 | /* |
1729 | * If we use privilege separation, the unprivileged child transfers | |
1730 | * the current keystate and exits | |
1731 | */ | |
1732 | if (use_privsep) { | |
b5a28cbc | 1733 | mm_send_keystate(pmonitor); |
1853d1ef | 1734 | exit(0); |
324bf712 | 1735 | } |
1853d1ef | 1736 | |
1737 | authenticated: | |
678143bd | 1738 | /* |
1739 | * Cancel the alarm we set to limit the time taken for | |
1740 | * authentication. | |
1741 | */ | |
1742 | alarm(0); | |
1743 | signal(SIGALRM, SIG_DFL); | |
1744 | if (startup_pipe != -1) { | |
1745 | close(startup_pipe); | |
1746 | startup_pipe = -1; | |
1747 | } | |
1748 | ||
6039eeef | 1749 | #ifdef SSH_AUDIT_EVENTS |
1750 | audit_event(SSH_AUTH_SUCCESS); | |
c00e4d75 | 1751 | #endif |
1752 | ||
762715ce | 1753 | /* |
1853d1ef | 1754 | * In privilege separation, we fork another child and prepare |
1755 | * file descriptor passing. | |
1756 | */ | |
1757 | if (use_privsep) { | |
324bf712 | 1758 | privsep_postauth(authctxt); |
1759 | /* the monitor process [priv] will not return */ | |
1853d1ef | 1760 | if (!compat20) |
1761 | destroy_sensitive_data(); | |
1762 | } | |
1b34c1b3 | 1763 | |
2362db19 | 1764 | /* Start session. */ |
1b34c1b3 | 1765 | do_authenticated(authctxt); |
1766 | ||
63284fbb | 1767 | /* The connection has been terminated. */ |
1768 | verbose("Closing connection to %.100s", remote_ip); | |
8efc0c15 | 1769 | |
d94aa2ae | 1770 | #ifdef USE_PAM |
7fceb20d | 1771 | if (options.use_pam) |
1772 | finish_pam(); | |
d94aa2ae | 1773 | #endif /* USE_PAM */ |
8efc0c15 | 1774 | |
2b0c0925 | 1775 | #ifdef SSH_AUDIT_EVENTS |
1776 | PRIVSEP(audit_event(SSH_CONNECTION_CLOSE)); | |
1777 | #endif | |
1778 | ||
5260325f | 1779 | packet_close(); |
1853d1ef | 1780 | |
1781 | if (use_privsep) | |
1782 | mm_terminate(); | |
1783 | ||
5260325f | 1784 | exit(0); |
1785 | } | |
8efc0c15 | 1786 | |
4f08e98d | 1787 | /* |
1788 | * Decrypt session_key_int using our private server key and private host key | |
1789 | * (key with larger modulus first). | |
1790 | */ | |
1853d1ef | 1791 | int |
4f08e98d | 1792 | ssh1_session_key(BIGNUM *session_key_int) |
1793 | { | |
1794 | int rsafail = 0; | |
1795 | ||
1796 | if (BN_cmp(sensitive_data.server_key->rsa->n, sensitive_data.ssh1_host_key->rsa->n) > 0) { | |
1797 | /* Server key has bigger modulus. */ | |
1798 | if (BN_num_bits(sensitive_data.server_key->rsa->n) < | |
1799 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + SSH_KEY_BITS_RESERVED) { | |
1800 | fatal("do_connection: %s: server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d", | |
1801 | get_remote_ipaddr(), | |
1802 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
1803 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), | |
1804 | SSH_KEY_BITS_RESERVED); | |
1805 | } | |
1806 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1807 | sensitive_data.server_key->rsa) <= 0) | |
1808 | rsafail++; | |
1809 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1810 | sensitive_data.ssh1_host_key->rsa) <= 0) | |
1811 | rsafail++; | |
1812 | } else { | |
1813 | /* Host key has bigger modulus (or they are equal). */ | |
1814 | if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) < | |
1815 | BN_num_bits(sensitive_data.server_key->rsa->n) + SSH_KEY_BITS_RESERVED) { | |
1816 | fatal("do_connection: %s: host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d", | |
1817 | get_remote_ipaddr(), | |
1818 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), | |
1819 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
1820 | SSH_KEY_BITS_RESERVED); | |
1821 | } | |
1822 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1823 | sensitive_data.ssh1_host_key->rsa) < 0) | |
1824 | rsafail++; | |
1825 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1826 | sensitive_data.server_key->rsa) < 0) | |
1827 | rsafail++; | |
1828 | } | |
1829 | return (rsafail); | |
1830 | } | |
5260325f | 1831 | /* |
7b2ea3a1 | 1832 | * SSH1 key exchange |
5260325f | 1833 | */ |
396c147e | 1834 | static void |
1e3b8b07 | 1835 | do_ssh1_kex(void) |
8efc0c15 | 1836 | { |
5260325f | 1837 | int i, len; |
46aa2d1f | 1838 | int rsafail = 0; |
5260325f | 1839 | BIGNUM *session_key_int; |
1e3b8b07 | 1840 | u_char session_key[SSH_SESSION_KEY_LENGTH]; |
1841 | u_char cookie[8]; | |
1842 | u_int cipher_type, auth_mask, protocol_flags; | |
7fdc56c5 | 1843 | u_int32_t rnd = 0; |
5260325f | 1844 | |
aa3378df | 1845 | /* |
1846 | * Generate check bytes that the client must send back in the user | |
1847 | * packet in order for it to be accepted; this is used to defy ip | |
1848 | * spoofing attacks. Note that this only works against somebody | |
1849 | * doing IP spoofing from a remote machine; any machine on the local | |
1850 | * network can still see outgoing packets and catch the random | |
1851 | * cookie. This only affects rhosts authentication, and this is one | |
1852 | * of the reasons why it is inherently insecure. | |
1853 | */ | |
5260325f | 1854 | for (i = 0; i < 8; i++) { |
1855 | if (i % 4 == 0) | |
7fdc56c5 | 1856 | rnd = arc4random(); |
1857 | cookie[i] = rnd & 0xff; | |
1858 | rnd >>= 8; | |
5260325f | 1859 | } |
1860 | ||
aa3378df | 1861 | /* |
1862 | * Send our public key. We include in the packet 64 bits of random | |
1863 | * data that must be matched in the reply in order to prevent IP | |
1864 | * spoofing. | |
1865 | */ | |
5260325f | 1866 | packet_start(SSH_SMSG_PUBLIC_KEY); |
1867 | for (i = 0; i < 8; i++) | |
7b2ea3a1 | 1868 | packet_put_char(cookie[i]); |
5260325f | 1869 | |
1870 | /* Store our public server RSA key. */ | |
fa08c86b | 1871 | packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n)); |
1872 | packet_put_bignum(sensitive_data.server_key->rsa->e); | |
1873 | packet_put_bignum(sensitive_data.server_key->rsa->n); | |
5260325f | 1874 | |
1875 | /* Store our public host RSA key. */ | |
fa08c86b | 1876 | packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); |
1877 | packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e); | |
1878 | packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n); | |
5260325f | 1879 | |
1880 | /* Put protocol flags. */ | |
1881 | packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN); | |
1882 | ||
1883 | /* Declare which ciphers we support. */ | |
94ec8c6b | 1884 | packet_put_int(cipher_mask_ssh1(0)); |
5260325f | 1885 | |
1886 | /* Declare supported authentication types. */ | |
1887 | auth_mask = 0; | |
5260325f | 1888 | if (options.rhosts_rsa_authentication) |
1889 | auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA; | |
1890 | if (options.rsa_authentication) | |
1891 | auth_mask |= 1 << SSH_AUTH_RSA; | |
5ba55ada | 1892 | if (options.challenge_response_authentication == 1) |
5260325f | 1893 | auth_mask |= 1 << SSH_AUTH_TIS; |
5260325f | 1894 | if (options.password_authentication) |
1895 | auth_mask |= 1 << SSH_AUTH_PASSWORD; | |
1896 | packet_put_int(auth_mask); | |
1897 | ||
1898 | /* Send the packet and wait for it to be sent. */ | |
1899 | packet_send(); | |
1900 | packet_write_wait(); | |
1901 | ||
fa08c86b | 1902 | debug("Sent %d bit server key and %d bit host key.", |
1903 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
1904 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); | |
5260325f | 1905 | |
1906 | /* Read clients reply (cipher type and session key). */ | |
54a5250f | 1907 | packet_read_expect(SSH_CMSG_SESSION_KEY); |
5260325f | 1908 | |
2d86a6cc | 1909 | /* Get cipher type and check whether we accept this. */ |
5260325f | 1910 | cipher_type = packet_get_char(); |
1911 | ||
94ec8c6b | 1912 | if (!(cipher_mask_ssh1(0) & (1 << cipher_type))) |
2d86a6cc | 1913 | packet_disconnect("Warning: client selects unsupported cipher."); |
1914 | ||
5260325f | 1915 | /* Get check bytes from the packet. These must match those we |
1916 | sent earlier with the public key packet. */ | |
1917 | for (i = 0; i < 8; i++) | |
7b2ea3a1 | 1918 | if (cookie[i] != packet_get_char()) |
5260325f | 1919 | packet_disconnect("IP Spoofing check bytes do not match."); |
1920 | ||
1921 | debug("Encryption type: %.200s", cipher_name(cipher_type)); | |
1922 | ||
1923 | /* Get the encrypted integer. */ | |
b775c6f2 | 1924 | if ((session_key_int = BN_new()) == NULL) |
1925 | fatal("do_ssh1_kex: BN_new failed"); | |
20b279e6 | 1926 | packet_get_bignum(session_key_int); |
5260325f | 1927 | |
5260325f | 1928 | protocol_flags = packet_get_int(); |
1929 | packet_set_protocol_flags(protocol_flags); | |
95500969 | 1930 | packet_check_eom(); |
5260325f | 1931 | |
4f08e98d | 1932 | /* Decrypt session_key_int using host/server keys */ |
1853d1ef | 1933 | rsafail = PRIVSEP(ssh1_session_key(session_key_int)); |
1934 | ||
aa3378df | 1935 | /* |
1936 | * Extract session key from the decrypted integer. The key is in the | |
1937 | * least significant 256 bits of the integer; the first byte of the | |
1938 | * key is in the highest bits. | |
1939 | */ | |
46aa2d1f | 1940 | if (!rsafail) { |
1941 | BN_mask_bits(session_key_int, sizeof(session_key) * 8); | |
1942 | len = BN_num_bytes(session_key_int); | |
2ceb8101 | 1943 | if (len < 0 || (u_int)len > sizeof(session_key)) { |
46aa2d1f | 1944 | error("do_connection: bad session key len from %s: " |
5ca51e19 | 1945 | "session_key_int %d > sizeof(session_key) %lu", |
1946 | get_remote_ipaddr(), len, (u_long)sizeof(session_key)); | |
46aa2d1f | 1947 | rsafail++; |
1948 | } else { | |
1949 | memset(session_key, 0, sizeof(session_key)); | |
1950 | BN_bn2bin(session_key_int, | |
1951 | session_key + sizeof(session_key) - len); | |
00be5382 | 1952 | |
8bbf1fa6 | 1953 | derive_ssh1_session_id( |
f2107e97 | 1954 | sensitive_data.ssh1_host_key->rsa->n, |
8bbf1fa6 | 1955 | sensitive_data.server_key->rsa->n, |
1956 | cookie, session_id); | |
00be5382 | 1957 | /* |
1958 | * Xor the first 16 bytes of the session key with the | |
1959 | * session id. | |
1960 | */ | |
1961 | for (i = 0; i < 16; i++) | |
1962 | session_key[i] ^= session_id[i]; | |
46aa2d1f | 1963 | } |
1964 | } | |
1965 | if (rsafail) { | |
00be5382 | 1966 | int bytes = BN_num_bytes(session_key_int); |
f6b1ba8f | 1967 | u_char *buf = xmalloc(bytes); |
00be5382 | 1968 | MD5_CTX md; |
1969 | ||
bbe88b6d | 1970 | logit("do_connection: generating a fake encryption key"); |
00be5382 | 1971 | BN_bn2bin(session_key_int, buf); |
1972 | MD5_Init(&md); | |
1973 | MD5_Update(&md, buf, bytes); | |
1974 | MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); | |
1975 | MD5_Final(session_key, &md); | |
1976 | MD5_Init(&md); | |
1977 | MD5_Update(&md, session_key, 16); | |
1978 | MD5_Update(&md, buf, bytes); | |
1979 | MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); | |
1980 | MD5_Final(session_key + 16, &md); | |
1981 | memset(buf, 0, bytes); | |
1982 | xfree(buf); | |
0572fe75 | 1983 | for (i = 0; i < 16; i++) |
1984 | session_id[i] = session_key[i] ^ session_key[i + 16]; | |
46aa2d1f | 1985 | } |
1853d1ef | 1986 | /* Destroy the private and public keys. No longer. */ |
63284fbb | 1987 | destroy_sensitive_data(); |
00be5382 | 1988 | |
1853d1ef | 1989 | if (use_privsep) |
1990 | mm_ssh1_session_id(session_id); | |
1991 | ||
7b2ea3a1 | 1992 | /* Destroy the decrypted integer. It is no longer needed. */ |
1993 | BN_clear_free(session_key_int); | |
1994 | ||
5260325f | 1995 | /* Set the session key. From this on all communications will be encrypted. */ |
1996 | packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type); | |
1997 | ||
1998 | /* Destroy our copy of the session key. It is no longer needed. */ | |
1999 | memset(session_key, 0, sizeof(session_key)); | |
2000 | ||
2001 | debug("Received session key; encryption turned on."); | |
2002 | ||
c242fc96 | 2003 | /* Send an acknowledgment packet. Note that this packet is sent encrypted. */ |
5260325f | 2004 | packet_start(SSH_SMSG_SUCCESS); |
2005 | packet_send(); | |
2006 | packet_write_wait(); | |
5260325f | 2007 | } |
e78a59f5 | 2008 | |
2009 | /* | |
2010 | * SSH2 key exchange: diffie-hellman-group1-sha1 | |
2011 | */ | |
396c147e | 2012 | static void |
1e3b8b07 | 2013 | do_ssh2_kex(void) |
e78a59f5 | 2014 | { |
e78a59f5 | 2015 | Kex *kex; |
e78a59f5 | 2016 | |
a8be9f80 | 2017 | if (options.ciphers != NULL) { |
6ae2364d | 2018 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = |
a8be9f80 | 2019 | myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; |
2020 | } | |
1ad64a93 | 2021 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = |
2022 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]); | |
2023 | myproposal[PROPOSAL_ENC_ALGS_STOC] = | |
2024 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); | |
2025 | ||
b2552997 | 2026 | if (options.macs != NULL) { |
2027 | myproposal[PROPOSAL_MAC_ALGS_CTOS] = | |
2028 | myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; | |
2029 | } | |
07200973 | 2030 | if (options.compression == COMP_NONE) { |
636f76ca | 2031 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = |
2032 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "none"; | |
07200973 | 2033 | } else if (options.compression == COMP_DELAYED) { |
2034 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = | |
2035 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com"; | |
636f76ca | 2036 | } |
07200973 | 2037 | |
fa08c86b | 2038 | myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = list_hostkey_types(); |
2039 | ||
7a37c112 | 2040 | /* start key exchange */ |
d8ee838b | 2041 | kex = kex_setup(myproposal); |
98a58eda | 2042 | kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server; |
41e5bd9a | 2043 | kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server; |
98a58eda | 2044 | kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; |
a5c9ffdb | 2045 | kex->server = 1; |
2046 | kex->client_version_string=client_version_string; | |
2047 | kex->server_version_string=server_version_string; | |
2048 | kex->load_host_key=&get_hostkey_by_type; | |
1853d1ef | 2049 | kex->host_key_index=&get_hostkey_index; |
94ec8c6b | 2050 | |
7a37c112 | 2051 | xxx_kex = kex; |
2052 | ||
c422989b | 2053 | dispatch_run(DISPATCH_BLOCK, &kex->done, kex); |
94ec8c6b | 2054 | |
d1ac6175 | 2055 | session_id2 = kex->session_id; |
2056 | session_id2_len = kex->session_id_len; | |
2057 | ||
94ec8c6b | 2058 | #ifdef DEBUG_KEXDH |
2059 | /* send 1st encrypted/maced/compressed message */ | |
2060 | packet_start(SSH2_MSG_IGNORE); | |
2061 | packet_put_cstring("markus"); | |
2062 | packet_send(); | |
2063 | packet_write_wait(); | |
2064 | #endif | |
a5c9ffdb | 2065 | debug("KEX done"); |
e78a59f5 | 2066 | } |
2362db19 | 2067 | |
2068 | /* server specific fatal cleanup */ | |
2069 | void | |
2070 | cleanup_exit(int i) | |
2071 | { | |
2072 | if (the_authctxt) | |
2073 | do_cleanup(the_authctxt); | |
6039eeef | 2074 | #ifdef SSH_AUDIT_EVENTS |
c00e4d75 | 2075 | /* done after do_cleanup so it can cancel the PAM auth 'thread' */ |
2076 | if (!use_privsep || mm_is_monitor()) | |
6039eeef | 2077 | audit_event(SSH_CONNECTION_ABANDON); |
c00e4d75 | 2078 | #endif |
2362db19 | 2079 | _exit(i); |
2080 | } |