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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 | |
b5b88c19 | 54 | #ifdef HAVE_PATHS_H |
a75f5360 | 55 | #include <paths.h> |
b5b88c19 | 56 | #endif |
ada68823 | 57 | #include <signal.h> |
8efc0c15 | 58 | |
42f11eb2 | 59 | #include <openssl/dh.h> |
60 | #include <openssl/bn.h> | |
436c347c | 61 | #include <openssl/md5.h> |
1853d1ef | 62 | #include <openssl/rand.h> |
6e879cb4 | 63 | #ifdef HAVE_SECUREWARE |
64 | #include <sys/security.h> | |
65 | #include <prot.h> | |
66 | #endif | |
42f11eb2 | 67 | |
68 | #include "ssh.h" | |
69 | #include "ssh1.h" | |
70 | #include "ssh2.h" | |
8efc0c15 | 71 | #include "xmalloc.h" |
72 | #include "rsa.h" | |
1729c161 | 73 | #include "sshpty.h" |
8efc0c15 | 74 | #include "packet.h" |
42f11eb2 | 75 | #include "log.h" |
8efc0c15 | 76 | #include "servconf.h" |
77 | #include "uidswap.h" | |
78 | #include "compat.h" | |
7368a6c8 | 79 | #include "buffer.h" |
b9a549d7 | 80 | #include "bufaux.h" |
42f11eb2 | 81 | #include "cipher.h" |
e78a59f5 | 82 | #include "kex.h" |
7368a6c8 | 83 | #include "key.h" |
94ec8c6b | 84 | #include "dh.h" |
e78a59f5 | 85 | #include "myproposal.h" |
a306f2dd | 86 | #include "authfile.h" |
42f11eb2 | 87 | #include "pathnames.h" |
88 | #include "atomicio.h" | |
89 | #include "canohost.h" | |
90 | #include "auth.h" | |
91 | #include "misc.h" | |
b9a549d7 | 92 | #include "msg.h" |
a5c9ffdb | 93 | #include "dispatch.h" |
e4d7f734 | 94 | #include "channels.h" |
1b34c1b3 | 95 | #include "session.h" |
1853d1ef | 96 | #include "monitor_mm.h" |
97 | #include "monitor.h" | |
98 | #include "monitor_wrap.h" | |
99 | #include "monitor_fdpass.h" | |
8efc0c15 | 100 | |
101 | #ifdef LIBWRAP | |
102 | #include <tcpd.h> | |
103 | #include <syslog.h> | |
104 | int allow_severity = LOG_INFO; | |
105 | int deny_severity = LOG_WARNING; | |
106 | #endif /* LIBWRAP */ | |
107 | ||
108 | #ifndef O_NOCTTY | |
109 | #define O_NOCTTY 0 | |
110 | #endif | |
111 | ||
b250e837 | 112 | /* Re-exec fds */ |
113 | #define REEXEC_DEVCRYPTO_RESERVED_FD (STDERR_FILENO + 1) | |
114 | #define REEXEC_STARTUP_PIPE_FD (STDERR_FILENO + 2) | |
115 | #define REEXEC_CONFIG_PASS_FD (STDERR_FILENO + 3) | |
116 | #define REEXEC_MIN_FREE_FD (STDERR_FILENO + 4) | |
117 | ||
260d427b | 118 | extern char *__progname; |
260d427b | 119 | |
8efc0c15 | 120 | /* Server configuration options. */ |
121 | ServerOptions options; | |
122 | ||
123 | /* Name of the server configuration file. */ | |
42f11eb2 | 124 | char *config_file_name = _PATH_SERVER_CONFIG_FILE; |
8efc0c15 | 125 | |
5260325f | 126 | /* |
127 | * Debug mode flag. This can be set on the command line. If debug | |
128 | * mode is enabled, extra debugging output will be sent to the system | |
129 | * log, the daemon will not go to background, and will exit after processing | |
130 | * the first connection. | |
131 | */ | |
8efc0c15 | 132 | int debug_flag = 0; |
133 | ||
f87f09aa | 134 | /* Flag indicating that the daemon should only test the configuration and keys. */ |
135 | int test_flag = 0; | |
136 | ||
8efc0c15 | 137 | /* Flag indicating that the daemon is being started from inetd. */ |
138 | int inetd_flag = 0; | |
139 | ||
0b6fbf03 | 140 | /* Flag indicating that sshd should not detach and become a daemon. */ |
141 | int no_daemon_flag = 0; | |
142 | ||
6a17f9c2 | 143 | /* debug goes to stderr unless inetd_flag is set */ |
144 | int log_stderr = 0; | |
145 | ||
8efc0c15 | 146 | /* Saved arguments to main(). */ |
147 | char **saved_argv; | |
4d33e531 | 148 | int saved_argc; |
8efc0c15 | 149 | |
b9a549d7 | 150 | /* re-exec */ |
151 | int rexeced_flag = 0; | |
152 | int rexec_flag = 1; | |
153 | int rexec_argc = 0; | |
154 | char **rexec_argv; | |
155 | ||
aa3378df | 156 | /* |
48e671d5 | 157 | * The sockets that the server is listening; this is used in the SIGHUP |
158 | * signal handler. | |
aa3378df | 159 | */ |
48e671d5 | 160 | #define MAX_LISTEN_SOCKS 16 |
161 | int listen_socks[MAX_LISTEN_SOCKS]; | |
162 | int num_listen_socks = 0; | |
8efc0c15 | 163 | |
aa3378df | 164 | /* |
165 | * the client's version string, passed by sshd2 in compat mode. if != NULL, | |
166 | * sshd will skip the version-number exchange | |
167 | */ | |
5260325f | 168 | char *client_version_string = NULL; |
7368a6c8 | 169 | char *server_version_string = NULL; |
8efc0c15 | 170 | |
7a37c112 | 171 | /* for rekeying XXX fixme */ |
172 | Kex *xxx_kex; | |
173 | ||
aa3378df | 174 | /* |
175 | * Any really sensitive data in the application is contained in this | |
176 | * structure. The idea is that this structure could be locked into memory so | |
177 | * that the pages do not get written into swap. However, there are some | |
178 | * problems. The private key contains BIGNUMs, and we do not (in principle) | |
179 | * have access to the internals of them, and locking just the structure is | |
180 | * not very useful. Currently, memory locking is not implemented. | |
181 | */ | |
5260325f | 182 | struct { |
cb7bd922 | 183 | Key *server_key; /* ephemeral server key */ |
fa08c86b | 184 | Key *ssh1_host_key; /* ssh1 host key */ |
185 | Key **host_keys; /* all private host keys */ | |
186 | int have_ssh1_key; | |
187 | int have_ssh2_key; | |
00be5382 | 188 | u_char ssh1_cookie[SSH_SESSION_KEY_LENGTH]; |
8efc0c15 | 189 | } sensitive_data; |
190 | ||
aa3378df | 191 | /* |
59c97189 | 192 | * Flag indicating whether the RSA server key needs to be regenerated. |
193 | * Is set in the SIGALRM handler and cleared when the key is regenerated. | |
aa3378df | 194 | */ |
7a934d1b | 195 | static volatile sig_atomic_t key_do_regen = 0; |
8efc0c15 | 196 | |
c9130033 | 197 | /* This is set to true when a signal is received. */ |
7a934d1b | 198 | static volatile sig_atomic_t received_sighup = 0; |
199 | static volatile sig_atomic_t received_sigterm = 0; | |
8efc0c15 | 200 | |
7368a6c8 | 201 | /* session identifier, used by RSA-auth */ |
1e3b8b07 | 202 | u_char session_id[16]; |
e7c0f9d5 | 203 | |
a306f2dd | 204 | /* same for ssh2 */ |
1e3b8b07 | 205 | u_char *session_id2 = NULL; |
a27002e5 | 206 | u_int session_id2_len = 0; |
a306f2dd | 207 | |
c345cf9d | 208 | /* record remote hostname or ip */ |
1e3b8b07 | 209 | u_int utmp_len = MAXHOSTNAMELEN; |
c345cf9d | 210 | |
7ace8c3b | 211 | /* options.max_startup sized array of fd ints */ |
212 | int *startup_pipes = NULL; | |
213 | int startup_pipe; /* in child */ | |
214 | ||
1853d1ef | 215 | /* variables used for privilege separation */ |
98a58eda | 216 | int use_privsep; |
a9b33b95 | 217 | struct monitor *pmonitor = NULL; |
1853d1ef | 218 | |
2362db19 | 219 | /* global authentication context */ |
220 | Authctxt *the_authctxt = NULL; | |
221 | ||
be2ca0c9 | 222 | /* message to be displayed after login */ |
223 | Buffer loginmsg; | |
224 | ||
7368a6c8 | 225 | /* Prototypes for various functions defined later in this file. */ |
396c147e | 226 | void destroy_sensitive_data(void); |
1853d1ef | 227 | void demote_sensitive_data(void); |
c8d54615 | 228 | |
396c147e | 229 | static void do_ssh1_kex(void); |
230 | static void do_ssh2_kex(void); | |
94ec8c6b | 231 | |
48e671d5 | 232 | /* |
233 | * Close all listening sockets | |
234 | */ | |
396c147e | 235 | static void |
48e671d5 | 236 | close_listen_socks(void) |
237 | { | |
238 | int i; | |
e424e241 | 239 | |
48e671d5 | 240 | for (i = 0; i < num_listen_socks; i++) |
241 | close(listen_socks[i]); | |
242 | num_listen_socks = -1; | |
243 | } | |
244 | ||
7ace8c3b | 245 | static void |
246 | close_startup_pipes(void) | |
247 | { | |
248 | int i; | |
e424e241 | 249 | |
7ace8c3b | 250 | if (startup_pipes) |
251 | for (i = 0; i < options.max_startups; i++) | |
252 | if (startup_pipes[i] != -1) | |
253 | close(startup_pipes[i]); | |
254 | } | |
255 | ||
5260325f | 256 | /* |
257 | * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP; | |
258 | * the effect is to reread the configuration file (and to regenerate | |
259 | * the server key). | |
260 | */ | |
396c147e | 261 | static void |
5260325f | 262 | sighup_handler(int sig) |
8efc0c15 | 263 | { |
6056eb35 | 264 | int save_errno = errno; |
265 | ||
5260325f | 266 | received_sighup = 1; |
267 | signal(SIGHUP, sighup_handler); | |
6056eb35 | 268 | errno = save_errno; |
8efc0c15 | 269 | } |
270 | ||
5260325f | 271 | /* |
272 | * Called from the main program after receiving SIGHUP. | |
273 | * Restarts the server. | |
274 | */ | |
396c147e | 275 | static void |
5ca51e19 | 276 | sighup_restart(void) |
8efc0c15 | 277 | { |
bbe88b6d | 278 | logit("Received SIGHUP; restarting."); |
48e671d5 | 279 | close_listen_socks(); |
7ace8c3b | 280 | close_startup_pipes(); |
5260325f | 281 | execv(saved_argv[0], saved_argv); |
bbe88b6d | 282 | logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0], |
e424e241 | 283 | strerror(errno)); |
5260325f | 284 | exit(1); |
8efc0c15 | 285 | } |
286 | ||
5260325f | 287 | /* |
288 | * Generic signal handler for terminating signals in the master daemon. | |
5260325f | 289 | */ |
396c147e | 290 | static void |
5260325f | 291 | sigterm_handler(int sig) |
8efc0c15 | 292 | { |
c9130033 | 293 | received_sigterm = sig; |
8efc0c15 | 294 | } |
295 | ||
5260325f | 296 | /* |
297 | * SIGCHLD handler. This is called whenever a child dies. This will then | |
c9130033 | 298 | * reap any zombies left by exited children. |
5260325f | 299 | */ |
396c147e | 300 | static void |
5260325f | 301 | main_sigchld_handler(int sig) |
8efc0c15 | 302 | { |
5260325f | 303 | int save_errno = errno; |
e424e241 | 304 | pid_t pid; |
5260325f | 305 | int status; |
5ad13cd7 | 306 | |
8c38e88b | 307 | while ((pid = waitpid(-1, &status, WNOHANG)) > 0 || |
308 | (pid < 0 && errno == EINTR)) | |
5260325f | 309 | ; |
5ad13cd7 | 310 | |
5260325f | 311 | signal(SIGCHLD, main_sigchld_handler); |
312 | errno = save_errno; | |
8efc0c15 | 313 | } |
314 | ||
5260325f | 315 | /* |
316 | * Signal handler for the alarm after the login grace period has expired. | |
317 | */ | |
396c147e | 318 | static void |
5260325f | 319 | grace_alarm_handler(int sig) |
8efc0c15 | 320 | { |
c9130033 | 321 | /* XXX no idea how fix this signal handler */ |
322 | ||
a9b33b95 | 323 | if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0) |
324 | kill(pmonitor->m_pid, SIGALRM); | |
325 | ||
5260325f | 326 | /* Log error and exit. */ |
26b9a3d2 | 327 | fatal("Timeout before authentication for %s", get_remote_ipaddr()); |
5260325f | 328 | } |
8efc0c15 | 329 | |
5260325f | 330 | /* |
331 | * Signal handler for the key regeneration alarm. Note that this | |
332 | * alarm only occurs in the daemon waiting for connections, and it does not | |
333 | * do anything with the private key or random state before forking. | |
334 | * Thus there should be no concurrency control/asynchronous execution | |
335 | * problems. | |
336 | */ | |
396c147e | 337 | static void |
cb7bd922 | 338 | generate_ephemeral_server_key(void) |
fa08c86b | 339 | { |
7fdc56c5 | 340 | u_int32_t rnd = 0; |
00be5382 | 341 | int i; |
342 | ||
cd332296 | 343 | verbose("Generating %s%d bit RSA key.", |
76ca7b01 | 344 | sensitive_data.server_key ? "new " : "", options.server_key_bits); |
fa08c86b | 345 | if (sensitive_data.server_key != NULL) |
346 | key_free(sensitive_data.server_key); | |
cd332296 | 347 | sensitive_data.server_key = key_generate(KEY_RSA1, |
76ca7b01 | 348 | options.server_key_bits); |
349 | verbose("RSA key generation complete."); | |
00be5382 | 350 | |
351 | for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) { | |
352 | if (i % 4 == 0) | |
7fdc56c5 | 353 | rnd = arc4random(); |
354 | sensitive_data.ssh1_cookie[i] = rnd & 0xff; | |
355 | rnd >>= 8; | |
00be5382 | 356 | } |
357 | arc4random_stir(); | |
fa08c86b | 358 | } |
f546c780 | 359 | |
396c147e | 360 | static void |
5260325f | 361 | key_regeneration_alarm(int sig) |
362 | { | |
363 | int save_errno = errno; | |
e424e241 | 364 | |
59c97189 | 365 | signal(SIGALRM, SIG_DFL); |
5260325f | 366 | errno = save_errno; |
59c97189 | 367 | key_do_regen = 1; |
5260325f | 368 | } |
8efc0c15 | 369 | |
396c147e | 370 | static void |
7368a6c8 | 371 | sshd_exchange_identification(int sock_in, int sock_out) |
372 | { | |
2ceb8101 | 373 | u_int i; |
374 | int mismatch; | |
7368a6c8 | 375 | int remote_major, remote_minor; |
a8be9f80 | 376 | int major, minor; |
7368a6c8 | 377 | char *s; |
378 | char buf[256]; /* Must not be larger than remote_version. */ | |
379 | char remote_version[256]; /* Must be at least as big as buf. */ | |
380 | ||
a8be9f80 | 381 | if ((options.protocol & SSH_PROTO_1) && |
382 | (options.protocol & SSH_PROTO_2)) { | |
383 | major = PROTOCOL_MAJOR_1; | |
384 | minor = 99; | |
385 | } else if (options.protocol & SSH_PROTO_2) { | |
386 | major = PROTOCOL_MAJOR_2; | |
387 | minor = PROTOCOL_MINOR_2; | |
388 | } else { | |
389 | major = PROTOCOL_MAJOR_1; | |
390 | minor = PROTOCOL_MINOR_1; | |
391 | } | |
392 | snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", major, minor, SSH_VERSION); | |
7368a6c8 | 393 | server_version_string = xstrdup(buf); |
394 | ||
7b390973 | 395 | /* Send our protocol version identification. */ |
396 | if (atomicio(vwrite, sock_out, server_version_string, | |
397 | strlen(server_version_string)) | |
398 | != strlen(server_version_string)) { | |
399 | logit("Could not write ident string to %s", get_remote_ipaddr()); | |
2362db19 | 400 | cleanup_exit(255); |
7b390973 | 401 | } |
402 | ||
403 | /* Read other sides version identification. */ | |
404 | memset(buf, 0, sizeof(buf)); | |
405 | for (i = 0; i < sizeof(buf) - 1; i++) { | |
406 | if (atomicio(read, sock_in, &buf[i], 1) != 1) { | |
407 | logit("Did not receive identification string from %s", | |
408 | get_remote_ipaddr()); | |
2362db19 | 409 | cleanup_exit(255); |
7368a6c8 | 410 | } |
7b390973 | 411 | if (buf[i] == '\r') { |
412 | buf[i] = 0; | |
413 | /* Kludge for F-Secure Macintosh < 1.0.2 */ | |
414 | if (i == 12 && | |
415 | strncmp(buf, "SSH-1.5-W1.0", 12) == 0) | |
7368a6c8 | 416 | break; |
7b390973 | 417 | continue; |
418 | } | |
419 | if (buf[i] == '\n') { | |
420 | buf[i] = 0; | |
421 | break; | |
7368a6c8 | 422 | } |
7368a6c8 | 423 | } |
7b390973 | 424 | buf[sizeof(buf) - 1] = 0; |
425 | client_version_string = xstrdup(buf); | |
7368a6c8 | 426 | |
427 | /* | |
428 | * Check that the versions match. In future this might accept | |
429 | * several versions and set appropriate flags to handle them. | |
430 | */ | |
431 | if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n", | |
432 | &remote_major, &remote_minor, remote_version) != 3) { | |
6ae2364d | 433 | s = "Protocol mismatch.\n"; |
dc54438a | 434 | (void) atomicio(vwrite, sock_out, s, strlen(s)); |
7368a6c8 | 435 | close(sock_in); |
436 | close(sock_out); | |
bbe88b6d | 437 | logit("Bad protocol version identification '%.100s' from %s", |
7368a6c8 | 438 | client_version_string, get_remote_ipaddr()); |
2362db19 | 439 | cleanup_exit(255); |
7368a6c8 | 440 | } |
441 | debug("Client protocol version %d.%d; client software version %.100s", | |
184eed6a | 442 | remote_major, remote_minor, remote_version); |
7368a6c8 | 443 | |
e78a59f5 | 444 | compat_datafellows(remote_version); |
445 | ||
9a87e2ac | 446 | if (datafellows & SSH_BUG_PROBE) { |
bbe88b6d | 447 | logit("probed from %s with %s. Don't panic.", |
9a87e2ac | 448 | get_remote_ipaddr(), client_version_string); |
2362db19 | 449 | cleanup_exit(255); |
9a87e2ac | 450 | } |
451 | ||
3a1c54d4 | 452 | if (datafellows & SSH_BUG_SCANNER) { |
bbe88b6d | 453 | logit("scanned from %s with %s. Don't panic.", |
3a1c54d4 | 454 | get_remote_ipaddr(), client_version_string); |
2362db19 | 455 | cleanup_exit(255); |
3a1c54d4 | 456 | } |
457 | ||
a8be9f80 | 458 | mismatch = 0; |
6aacefa7 | 459 | switch (remote_major) { |
7368a6c8 | 460 | case 1: |
a306f2dd | 461 | if (remote_minor == 99) { |
462 | if (options.protocol & SSH_PROTO_2) | |
463 | enable_compat20(); | |
464 | else | |
465 | mismatch = 1; | |
466 | break; | |
467 | } | |
a8be9f80 | 468 | if (!(options.protocol & SSH_PROTO_1)) { |
469 | mismatch = 1; | |
470 | break; | |
471 | } | |
7368a6c8 | 472 | if (remote_minor < 3) { |
089fbbd2 | 473 | packet_disconnect("Your ssh version is too old and " |
7368a6c8 | 474 | "is no longer supported. Please install a newer version."); |
475 | } else if (remote_minor == 3) { | |
476 | /* note that this disables agent-forwarding */ | |
477 | enable_compat13(); | |
478 | } | |
a8be9f80 | 479 | break; |
e78a59f5 | 480 | case 2: |
a8be9f80 | 481 | if (options.protocol & SSH_PROTO_2) { |
e78a59f5 | 482 | enable_compat20(); |
483 | break; | |
484 | } | |
485 | /* FALLTHROUGH */ | |
6ae2364d | 486 | default: |
a8be9f80 | 487 | mismatch = 1; |
488 | break; | |
489 | } | |
490 | chop(server_version_string); | |
a8be9f80 | 491 | debug("Local version string %.200s", server_version_string); |
492 | ||
493 | if (mismatch) { | |
7368a6c8 | 494 | s = "Protocol major versions differ.\n"; |
dc54438a | 495 | (void) atomicio(vwrite, sock_out, s, strlen(s)); |
7368a6c8 | 496 | close(sock_in); |
497 | close(sock_out); | |
bbe88b6d | 498 | logit("Protocol major versions differ for %s: %.200s vs. %.200s", |
a8be9f80 | 499 | get_remote_ipaddr(), |
500 | server_version_string, client_version_string); | |
2362db19 | 501 | cleanup_exit(255); |
7368a6c8 | 502 | } |
a306f2dd | 503 | } |
504 | ||
fa08c86b | 505 | /* Destroy the host and server keys. They will no longer be needed. */ |
a306f2dd | 506 | void |
507 | destroy_sensitive_data(void) | |
508 | { | |
fa08c86b | 509 | int i; |
510 | ||
511 | if (sensitive_data.server_key) { | |
512 | key_free(sensitive_data.server_key); | |
513 | sensitive_data.server_key = NULL; | |
514 | } | |
184eed6a | 515 | for (i = 0; i < options.num_host_key_files; i++) { |
fa08c86b | 516 | if (sensitive_data.host_keys[i]) { |
517 | key_free(sensitive_data.host_keys[i]); | |
518 | sensitive_data.host_keys[i] = NULL; | |
519 | } | |
520 | } | |
521 | sensitive_data.ssh1_host_key = NULL; | |
00be5382 | 522 | memset(sensitive_data.ssh1_cookie, 0, SSH_SESSION_KEY_LENGTH); |
fa08c86b | 523 | } |
fa08c86b | 524 | |
1853d1ef | 525 | /* Demote private to public keys for network child */ |
526 | void | |
527 | demote_sensitive_data(void) | |
528 | { | |
529 | Key *tmp; | |
530 | int i; | |
531 | ||
532 | if (sensitive_data.server_key) { | |
533 | tmp = key_demote(sensitive_data.server_key); | |
534 | key_free(sensitive_data.server_key); | |
535 | sensitive_data.server_key = tmp; | |
536 | } | |
537 | ||
538 | for (i = 0; i < options.num_host_key_files; i++) { | |
539 | if (sensitive_data.host_keys[i]) { | |
540 | tmp = key_demote(sensitive_data.host_keys[i]); | |
541 | key_free(sensitive_data.host_keys[i]); | |
542 | sensitive_data.host_keys[i] = tmp; | |
543 | if (tmp->type == KEY_RSA1) | |
544 | sensitive_data.ssh1_host_key = tmp; | |
545 | } | |
546 | } | |
547 | ||
548 | /* We do not clear ssh1_host key and cookie. XXX - Okay Niels? */ | |
549 | } | |
550 | ||
51aeb639 | 551 | static void |
1853d1ef | 552 | privsep_preauth_child(void) |
553 | { | |
7fdc56c5 | 554 | u_int32_t rnd[256]; |
6ded293b | 555 | gid_t gidset[1]; |
2ea6de2b | 556 | struct passwd *pw; |
e424e241 | 557 | int i; |
1853d1ef | 558 | |
559 | /* Enable challenge-response authentication for privilege separation */ | |
560 | privsep_challenge_enable(); | |
561 | ||
562 | for (i = 0; i < 256; i++) | |
7fdc56c5 | 563 | rnd[i] = arc4random(); |
564 | RAND_seed(rnd, sizeof(rnd)); | |
1853d1ef | 565 | |
566 | /* Demote the private keys to public keys. */ | |
567 | demote_sensitive_data(); | |
568 | ||
2ea6de2b | 569 | if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) |
cdc4fc39 | 570 | fatal("Privilege separation user %s does not exist", |
571 | SSH_PRIVSEP_USER); | |
2ea6de2b | 572 | memset(pw->pw_passwd, 0, strlen(pw->pw_passwd)); |
573 | endpwent(); | |
574 | ||
343288b8 | 575 | /* Change our root directory */ |
1c352e97 | 576 | if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1) |
577 | fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR, | |
578 | strerror(errno)); | |
1853d1ef | 579 | if (chdir("/") == -1) |
edfb66cb | 580 | fatal("chdir(\"/\"): %s", strerror(errno)); |
762715ce | 581 | |
1853d1ef | 582 | /* Drop our privileges */ |
2ea6de2b | 583 | debug3("privsep user:group %u:%u", (u_int)pw->pw_uid, |
584 | (u_int)pw->pw_gid); | |
87809a1f | 585 | #if 0 |
6ff58a4b | 586 | /* XXX not ready, too heavy after chroot */ |
2ea6de2b | 587 | do_setusercontext(pw); |
87809a1f | 588 | #else |
589 | gidset[0] = pw->pw_gid; | |
87809a1f | 590 | if (setgroups(1, gidset) < 0) |
591 | fatal("setgroups: %.100s", strerror(errno)); | |
592 | permanently_set_uid(pw); | |
593 | #endif | |
1853d1ef | 594 | } |
595 | ||
2362db19 | 596 | static int |
597 | privsep_preauth(Authctxt *authctxt) | |
1853d1ef | 598 | { |
1853d1ef | 599 | int status; |
324bf712 | 600 | pid_t pid; |
1853d1ef | 601 | |
324bf712 | 602 | /* Set up unprivileged child process to deal with network data */ |
b5a28cbc | 603 | pmonitor = monitor_init(); |
324bf712 | 604 | /* Store a pointer to the kex for later rekeying */ |
b5a28cbc | 605 | pmonitor->m_pkex = &xxx_kex; |
324bf712 | 606 | |
607 | pid = fork(); | |
608 | if (pid == -1) { | |
609 | fatal("fork of unprivileged child failed"); | |
610 | } else if (pid != 0) { | |
c457707e | 611 | debug2("Network child is on pid %ld", (long)pid); |
324bf712 | 612 | |
b5a28cbc | 613 | close(pmonitor->m_recvfd); |
a9b33b95 | 614 | pmonitor->m_pid = pid; |
2362db19 | 615 | monitor_child_preauth(authctxt, pmonitor); |
b5a28cbc | 616 | close(pmonitor->m_sendfd); |
324bf712 | 617 | |
618 | /* Sync memory */ | |
b5a28cbc | 619 | monitor_sync(pmonitor); |
324bf712 | 620 | |
621 | /* Wait for the child's exit status */ | |
8c38e88b | 622 | while (waitpid(pid, &status, 0) < 0) |
623 | if (errno != EINTR) | |
624 | break; | |
2362db19 | 625 | return (1); |
324bf712 | 626 | } else { |
627 | /* child */ | |
628 | ||
b5a28cbc | 629 | close(pmonitor->m_sendfd); |
324bf712 | 630 | |
631 | /* Demote the child */ | |
632 | if (getuid() == 0 || geteuid() == 0) | |
633 | privsep_preauth_child(); | |
47c36e5b | 634 | setproctitle("%s", "[net]"); |
324bf712 | 635 | } |
2362db19 | 636 | return (0); |
324bf712 | 637 | } |
638 | ||
639 | static void | |
640 | privsep_postauth(Authctxt *authctxt) | |
641 | { | |
94d8258b | 642 | #ifdef DISABLE_FD_PASSING |
d170feb1 | 643 | if (1) { |
644 | #else | |
1853d1ef | 645 | if (authctxt->pw->pw_uid == 0 || options.use_login) { |
d170feb1 | 646 | #endif |
1853d1ef | 647 | /* File descriptor passing is broken or root login */ |
1853d1ef | 648 | use_privsep = 0; |
ae25711b | 649 | goto skip; |
1853d1ef | 650 | } |
762715ce | 651 | |
1853d1ef | 652 | /* New socket pair */ |
b5a28cbc | 653 | monitor_reinit(pmonitor); |
1853d1ef | 654 | |
b5a28cbc | 655 | pmonitor->m_pid = fork(); |
656 | if (pmonitor->m_pid == -1) | |
1853d1ef | 657 | fatal("fork of unprivileged child failed"); |
b5a28cbc | 658 | else if (pmonitor->m_pid != 0) { |
c457707e | 659 | debug2("User child is on pid %ld", (long)pmonitor->m_pid); |
b5a28cbc | 660 | close(pmonitor->m_recvfd); |
f143ed33 | 661 | buffer_clear(&loginmsg); |
b5a28cbc | 662 | monitor_child_postauth(pmonitor); |
1853d1ef | 663 | |
664 | /* NEVERREACHED */ | |
665 | exit(0); | |
666 | } | |
667 | ||
b5a28cbc | 668 | close(pmonitor->m_sendfd); |
1853d1ef | 669 | |
670 | /* Demote the private keys to public keys. */ | |
671 | demote_sensitive_data(); | |
672 | ||
673 | /* Drop privileges */ | |
674 | do_setusercontext(authctxt->pw); | |
675 | ||
ae25711b | 676 | skip: |
1853d1ef | 677 | /* It is safe now to apply the key state */ |
b5a28cbc | 678 | monitor_apply_keystate(pmonitor); |
07200973 | 679 | |
680 | /* | |
681 | * Tell the packet layer that authentication was successful, since | |
682 | * this information is not part of the key state. | |
683 | */ | |
684 | packet_set_authenticated(); | |
1853d1ef | 685 | } |
686 | ||
396c147e | 687 | static char * |
fa08c86b | 688 | list_hostkey_types(void) |
689 | { | |
3469eac4 | 690 | Buffer b; |
b6c7b7b7 | 691 | const char *p; |
692 | char *ret; | |
fa08c86b | 693 | int i; |
3469eac4 | 694 | |
695 | buffer_init(&b); | |
184eed6a | 696 | for (i = 0; i < options.num_host_key_files; i++) { |
fa08c86b | 697 | Key *key = sensitive_data.host_keys[i]; |
698 | if (key == NULL) | |
699 | continue; | |
6aacefa7 | 700 | switch (key->type) { |
fa08c86b | 701 | case KEY_RSA: |
702 | case KEY_DSA: | |
3469eac4 | 703 | if (buffer_len(&b) > 0) |
704 | buffer_append(&b, ",", 1); | |
705 | p = key_ssh_name(key); | |
706 | buffer_append(&b, p, strlen(p)); | |
fa08c86b | 707 | break; |
708 | } | |
709 | } | |
3469eac4 | 710 | buffer_append(&b, "\0", 1); |
b6c7b7b7 | 711 | ret = xstrdup(buffer_ptr(&b)); |
3469eac4 | 712 | buffer_free(&b); |
b6c7b7b7 | 713 | debug("list_hostkey_types: %s", ret); |
714 | return ret; | |
fa08c86b | 715 | } |
716 | ||
1853d1ef | 717 | Key * |
fa08c86b | 718 | get_hostkey_by_type(int type) |
719 | { | |
720 | int i; | |
e424e241 | 721 | |
184eed6a | 722 | for (i = 0; i < options.num_host_key_files; i++) { |
fa08c86b | 723 | Key *key = sensitive_data.host_keys[i]; |
724 | if (key != NULL && key->type == type) | |
725 | return key; | |
726 | } | |
727 | return NULL; | |
7368a6c8 | 728 | } |
729 | ||
1853d1ef | 730 | Key * |
731 | get_hostkey_by_index(int ind) | |
732 | { | |
733 | if (ind < 0 || ind >= options.num_host_key_files) | |
734 | return (NULL); | |
735 | return (sensitive_data.host_keys[ind]); | |
736 | } | |
737 | ||
738 | int | |
739 | get_hostkey_index(Key *key) | |
740 | { | |
741 | int i; | |
e424e241 | 742 | |
1853d1ef | 743 | for (i = 0; i < options.num_host_key_files; i++) { |
744 | if (key == sensitive_data.host_keys[i]) | |
745 | return (i); | |
746 | } | |
747 | return (-1); | |
748 | } | |
749 | ||
c345cf9d | 750 | /* |
751 | * returns 1 if connection should be dropped, 0 otherwise. | |
752 | * dropping starts at connection #max_startups_begin with a probability | |
753 | * of (max_startups_rate/100). the probability increases linearly until | |
754 | * all connections are dropped for startups > max_startups | |
755 | */ | |
396c147e | 756 | static int |
c345cf9d | 757 | drop_connection(int startups) |
758 | { | |
1c5eab6f | 759 | int p, r; |
c345cf9d | 760 | |
761 | if (startups < options.max_startups_begin) | |
762 | return 0; | |
763 | if (startups >= options.max_startups) | |
764 | return 1; | |
765 | if (options.max_startups_rate == 100) | |
766 | return 1; | |
767 | ||
768 | p = 100 - options.max_startups_rate; | |
769 | p *= startups - options.max_startups_begin; | |
1c5eab6f | 770 | p /= options.max_startups - options.max_startups_begin; |
c345cf9d | 771 | p += options.max_startups_rate; |
1c5eab6f | 772 | r = arc4random() % 100; |
c345cf9d | 773 | |
e9aec1d4 | 774 | debug("drop_connection: p %d, r %d", p, r); |
c345cf9d | 775 | return (r < p) ? 1 : 0; |
776 | } | |
777 | ||
2717fa0f | 778 | static void |
779 | usage(void) | |
780 | { | |
85ac7a84 | 781 | fprintf(stderr, "%s, %s\n", |
4526e8c2 | 782 | SSH_RELEASE, SSLeay_version(SSLEAY_VERSION)); |
65edde94 | 783 | fprintf(stderr, |
784 | "usage: sshd [-46Ddeiqt] [-b bits] [-f config_file] [-g login_grace_time]\n" | |
785 | " [-h host_key_file] [-k key_gen_time] [-o option] [-p port] [-u len]\n" | |
786 | ); | |
2717fa0f | 787 | exit(1); |
788 | } | |
789 | ||
b9a549d7 | 790 | static void |
791 | send_rexec_state(int fd, Buffer *conf) | |
792 | { | |
793 | Buffer m; | |
794 | ||
795 | debug3("%s: entering fd = %d config len %d", __func__, fd, | |
796 | buffer_len(conf)); | |
797 | ||
798 | /* | |
799 | * Protocol from reexec master to child: | |
800 | * string configuration | |
801 | * u_int ephemeral_key_follows | |
802 | * bignum e (only if ephemeral_key_follows == 1) | |
803 | * bignum n " | |
804 | * bignum d " | |
805 | * bignum iqmp " | |
806 | * bignum p " | |
807 | * bignum q " | |
72f02ae7 | 808 | * string rngseed (only if OpenSSL is not self-seeded) |
b9a549d7 | 809 | */ |
810 | buffer_init(&m); | |
811 | buffer_put_cstring(&m, buffer_ptr(conf)); | |
812 | ||
f2107e97 | 813 | if (sensitive_data.server_key != NULL && |
b9a549d7 | 814 | sensitive_data.server_key->type == KEY_RSA1) { |
815 | buffer_put_int(&m, 1); | |
816 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->e); | |
817 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->n); | |
818 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->d); | |
819 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->iqmp); | |
820 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->p); | |
821 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->q); | |
822 | } else | |
823 | buffer_put_int(&m, 0); | |
824 | ||
72f02ae7 | 825 | #ifndef OPENSSL_PRNG_ONLY |
826 | rexec_send_rng_seed(&m); | |
827 | #endif | |
828 | ||
b9a549d7 | 829 | if (ssh_msg_send(fd, 0, &m) == -1) |
830 | fatal("%s: ssh_msg_send failed", __func__); | |
831 | ||
832 | buffer_free(&m); | |
833 | ||
834 | debug3("%s: done", __func__); | |
835 | } | |
836 | ||
837 | static void | |
838 | recv_rexec_state(int fd, Buffer *conf) | |
839 | { | |
840 | Buffer m; | |
841 | char *cp; | |
842 | u_int len; | |
843 | ||
844 | debug3("%s: entering fd = %d", __func__, fd); | |
845 | ||
846 | buffer_init(&m); | |
847 | ||
848 | if (ssh_msg_recv(fd, &m) == -1) | |
849 | fatal("%s: ssh_msg_recv failed", __func__); | |
850 | if (buffer_get_char(&m) != 0) | |
851 | fatal("%s: rexec version mismatch", __func__); | |
852 | ||
853 | cp = buffer_get_string(&m, &len); | |
854 | if (conf != NULL) | |
855 | buffer_append(conf, cp, len + 1); | |
856 | xfree(cp); | |
857 | ||
858 | if (buffer_get_int(&m)) { | |
859 | if (sensitive_data.server_key != NULL) | |
860 | key_free(sensitive_data.server_key); | |
861 | sensitive_data.server_key = key_new_private(KEY_RSA1); | |
862 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->e); | |
863 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->n); | |
864 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->d); | |
865 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->iqmp); | |
866 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->p); | |
867 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->q); | |
868 | rsa_generate_additional_parameters( | |
869 | sensitive_data.server_key->rsa); | |
870 | } | |
72f02ae7 | 871 | |
872 | #ifndef OPENSSL_PRNG_ONLY | |
873 | rexec_recv_rng_seed(&m); | |
874 | #endif | |
875 | ||
b9a549d7 | 876 | buffer_free(&m); |
877 | ||
878 | debug3("%s: done", __func__); | |
879 | } | |
880 | ||
5260325f | 881 | /* |
882 | * Main program for the daemon. | |
883 | */ | |
8efc0c15 | 884 | int |
885 | main(int ac, char **av) | |
886 | { | |
5260325f | 887 | extern char *optarg; |
888 | extern int optind; | |
83529a6b | 889 | int opt, j, i, fdsetsz, on = 1; |
890 | int sock_in = -1, sock_out = -1, newsock = -1; | |
9da5c3c9 | 891 | pid_t pid; |
48e671d5 | 892 | socklen_t fromlen; |
48e671d5 | 893 | fd_set *fdset; |
894 | struct sockaddr_storage from; | |
5260325f | 895 | const char *remote_ip; |
896 | int remote_port; | |
5260325f | 897 | FILE *f; |
48e671d5 | 898 | struct addrinfo *ai; |
899 | char ntop[NI_MAXHOST], strport[NI_MAXSERV]; | |
c5894280 | 900 | char *line; |
48e671d5 | 901 | int listen_sock, maxfd; |
9216f89c | 902 | int startup_p[2] = { -1 , -1 }, config_s[2] = { -1 , -1 }; |
089fbbd2 | 903 | int startups = 0; |
aeaa3d9e | 904 | Key *key; |
2362db19 | 905 | Authctxt *authctxt; |
59c97189 | 906 | int ret, key_used = 0; |
b9a549d7 | 907 | Buffer cfg; |
5260325f | 908 | |
6e879cb4 | 909 | #ifdef HAVE_SECUREWARE |
910 | (void)set_auth_parameters(ac, av); | |
911 | #endif | |
fda04d7d | 912 | __progname = ssh_get_progname(av[0]); |
264dce47 | 913 | init_rng(); |
914 | ||
d0104542 | 915 | /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */ |
4d33e531 | 916 | saved_argc = ac; |
7706b4c7 | 917 | rexec_argc = ac; |
f420d2ba | 918 | saved_argv = xmalloc(sizeof(*saved_argv) * (ac + 1)); |
d0104542 | 919 | for (i = 0; i < ac; i++) |
920 | saved_argv[i] = xstrdup(av[i]); | |
f420d2ba | 921 | saved_argv[i] = NULL; |
d0104542 | 922 | |
923 | #ifndef HAVE_SETPROCTITLE | |
924 | /* Prepare for later setproctitle emulation */ | |
925 | compat_init_setproctitle(ac, av); | |
416c732d | 926 | av = saved_argv; |
d0104542 | 927 | #endif |
5260325f | 928 | |
a4c0faa2 | 929 | if (geteuid() == 0 && setgroups(0, NULL) == -1) |
930 | debug("setgroups(): %.200s", strerror(errno)); | |
931 | ||
fd6168c1 | 932 | /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ |
933 | sanitise_stdfd(); | |
934 | ||
5260325f | 935 | /* Initialize configuration options to their default values. */ |
936 | initialize_server_options(&options); | |
937 | ||
938 | /* Parse command-line arguments. */ | |
b9a549d7 | 939 | while ((opt = getopt(ac, av, "f:p:b:k:h:g:u:o:dDeiqrtQR46")) != -1) { |
5260325f | 940 | switch (opt) { |
48e671d5 | 941 | case '4': |
31b41ceb | 942 | options.address_family = AF_INET; |
48e671d5 | 943 | break; |
944 | case '6': | |
31b41ceb | 945 | options.address_family = AF_INET6; |
48e671d5 | 946 | break; |
5260325f | 947 | case 'f': |
948 | config_file_name = optarg; | |
949 | break; | |
950 | case 'd': | |
e053cd2c | 951 | if (debug_flag == 0) { |
bcbf86ec | 952 | debug_flag = 1; |
953 | options.log_level = SYSLOG_LEVEL_DEBUG1; | |
e053cd2c | 954 | } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) |
bcbf86ec | 955 | options.log_level++; |
5260325f | 956 | break; |
0b6fbf03 | 957 | case 'D': |
958 | no_daemon_flag = 1; | |
959 | break; | |
ff14faf1 | 960 | case 'e': |
961 | log_stderr = 1; | |
962 | break; | |
5260325f | 963 | case 'i': |
964 | inetd_flag = 1; | |
965 | break; | |
b9a549d7 | 966 | case 'r': |
967 | rexec_flag = 0; | |
968 | break; | |
969 | case 'R': | |
970 | rexeced_flag = 1; | |
971 | inetd_flag = 1; | |
972 | break; | |
5260325f | 973 | case 'Q': |
9bd5b720 | 974 | /* ignored */ |
5260325f | 975 | break; |
976 | case 'q': | |
977 | options.log_level = SYSLOG_LEVEL_QUIET; | |
978 | break; | |
979 | case 'b': | |
980 | options.server_key_bits = atoi(optarg); | |
981 | break; | |
982 | case 'p': | |
48e671d5 | 983 | options.ports_from_cmdline = 1; |
bcbf86ec | 984 | if (options.num_ports >= MAX_PORTS) { |
985 | fprintf(stderr, "too many ports.\n"); | |
986 | exit(1); | |
987 | } | |
2d2a2c65 | 988 | options.ports[options.num_ports++] = a2port(optarg); |
989 | if (options.ports[options.num_ports-1] == 0) { | |
990 | fprintf(stderr, "Bad port number.\n"); | |
991 | exit(1); | |
992 | } | |
5260325f | 993 | break; |
994 | case 'g': | |
e2b1fb42 | 995 | if ((options.login_grace_time = convtime(optarg)) == -1) { |
996 | fprintf(stderr, "Invalid login grace time.\n"); | |
997 | exit(1); | |
998 | } | |
5260325f | 999 | break; |
1000 | case 'k': | |
e2b1fb42 | 1001 | if ((options.key_regeneration_time = convtime(optarg)) == -1) { |
1002 | fprintf(stderr, "Invalid key regeneration interval.\n"); | |
1003 | exit(1); | |
1004 | } | |
5260325f | 1005 | break; |
1006 | case 'h': | |
fa08c86b | 1007 | if (options.num_host_key_files >= MAX_HOSTKEYS) { |
1008 | fprintf(stderr, "too many host keys.\n"); | |
1009 | exit(1); | |
1010 | } | |
1011 | options.host_key_files[options.num_host_key_files++] = optarg; | |
5260325f | 1012 | break; |
f87f09aa | 1013 | case 't': |
1014 | test_flag = 1; | |
1015 | break; | |
c345cf9d | 1016 | case 'u': |
1017 | utmp_len = atoi(optarg); | |
67f04db1 | 1018 | if (utmp_len > MAXHOSTNAMELEN) { |
1019 | fprintf(stderr, "Invalid utmp length.\n"); | |
1020 | exit(1); | |
1021 | } | |
c345cf9d | 1022 | break; |
2717fa0f | 1023 | case 'o': |
c5894280 | 1024 | line = xstrdup(optarg); |
1025 | if (process_server_config_line(&options, line, | |
2717fa0f | 1026 | "command-line", 0) != 0) |
184eed6a | 1027 | exit(1); |
c5894280 | 1028 | xfree(line); |
2717fa0f | 1029 | break; |
5260325f | 1030 | case '?': |
1031 | default: | |
2717fa0f | 1032 | usage(); |
1033 | break; | |
5260325f | 1034 | } |
1035 | } | |
b9a549d7 | 1036 | if (rexeced_flag || inetd_flag) |
1037 | rexec_flag = 0; | |
1038 | if (rexec_flag && (av[0] == NULL || *av[0] != '/')) | |
1039 | fatal("sshd re-exec requires execution with an absolute path"); | |
1040 | if (rexeced_flag) | |
b250e837 | 1041 | closefrom(REEXEC_MIN_FREE_FD); |
1042 | else | |
1043 | closefrom(REEXEC_DEVCRYPTO_RESERVED_FD); | |
b9a549d7 | 1044 | |
1a92bd7e | 1045 | SSLeay_add_all_algorithms(); |
5260325f | 1046 | |
48e671d5 | 1047 | /* |
1048 | * Force logging to stderr until we have loaded the private host | |
1049 | * key (unless started from inetd) | |
1050 | */ | |
1fe6a48f | 1051 | log_init(__progname, |
980c9344 | 1052 | options.log_level == SYSLOG_LEVEL_NOT_SET ? |
1053 | SYSLOG_LEVEL_INFO : options.log_level, | |
1054 | options.log_facility == SYSLOG_FACILITY_NOT_SET ? | |
1055 | SYSLOG_FACILITY_AUTH : options.log_facility, | |
51efad8c | 1056 | log_stderr || !inetd_flag); |
48e671d5 | 1057 | |
351f44a0 | 1058 | /* |
1059 | * Unset KRB5CCNAME, otherwise the user's session may inherit it from | |
1060 | * root's environment | |
d1cf9a87 | 1061 | */ |
3bfd27d5 | 1062 | if (getenv("KRB5CCNAME") != NULL) |
1063 | unsetenv("KRB5CCNAME"); | |
1064 | ||
ef51930f | 1065 | #ifdef _UNICOS |
e5ba4718 | 1066 | /* Cray can define user privs drop all privs now! |
1a23ac2c | 1067 | * Not needed on PRIV_SU systems! |
1068 | */ | |
1069 | drop_cray_privs(); | |
1070 | #endif | |
1071 | ||
b9a549d7 | 1072 | sensitive_data.server_key = NULL; |
1073 | sensitive_data.ssh1_host_key = NULL; | |
1074 | sensitive_data.have_ssh1_key = 0; | |
1075 | sensitive_data.have_ssh2_key = 0; | |
1076 | ||
1077 | /* Fetch our configuration */ | |
1078 | buffer_init(&cfg); | |
1079 | if (rexeced_flag) | |
b250e837 | 1080 | recv_rexec_state(REEXEC_CONFIG_PASS_FD, &cfg); |
b9a549d7 | 1081 | else |
1082 | load_server_config(config_file_name, &cfg); | |
1083 | ||
1084 | parse_server_config(&options, | |
1085 | rexeced_flag ? "rexec" : config_file_name, &cfg); | |
1086 | ||
1087 | if (!rexec_flag) | |
1088 | buffer_free(&cfg); | |
5260325f | 1089 | |
72f02ae7 | 1090 | seed_rng(); |
1091 | ||
5260325f | 1092 | /* Fill in default values for those options not explicitly set. */ |
1093 | fill_default_server_options(&options); | |
1094 | ||
31b41ceb | 1095 | /* set default channel AF */ |
1096 | channel_set_af(options.address_family); | |
1097 | ||
5260325f | 1098 | /* Check that there are no remaining arguments. */ |
1099 | if (optind < ac) { | |
1100 | fprintf(stderr, "Extra argument %s.\n", av[optind]); | |
1101 | exit(1); | |
8efc0c15 | 1102 | } |
5260325f | 1103 | |
4526e8c2 | 1104 | debug("sshd version %.100s", SSH_RELEASE); |
5260325f | 1105 | |
fa08c86b | 1106 | /* load private host keys */ |
343288b8 | 1107 | sensitive_data.host_keys = xmalloc(options.num_host_key_files * |
1108 | sizeof(Key *)); | |
184eed6a | 1109 | for (i = 0; i < options.num_host_key_files; i++) |
1e3b8b07 | 1110 | sensitive_data.host_keys[i] = NULL; |
a306f2dd | 1111 | |
184eed6a | 1112 | for (i = 0; i < options.num_host_key_files; i++) { |
aeaa3d9e | 1113 | key = key_load_private(options.host_key_files[i], "", NULL); |
1114 | sensitive_data.host_keys[i] = key; | |
fa08c86b | 1115 | if (key == NULL) { |
58cfa257 | 1116 | error("Could not load host key: %s", |
1117 | options.host_key_files[i]); | |
aeaa3d9e | 1118 | sensitive_data.host_keys[i] = NULL; |
fa08c86b | 1119 | continue; |
a306f2dd | 1120 | } |
6aacefa7 | 1121 | switch (key->type) { |
fa08c86b | 1122 | case KEY_RSA1: |
1123 | sensitive_data.ssh1_host_key = key; | |
1124 | sensitive_data.have_ssh1_key = 1; | |
1125 | break; | |
1126 | case KEY_RSA: | |
1127 | case KEY_DSA: | |
1128 | sensitive_data.have_ssh2_key = 1; | |
1129 | break; | |
a306f2dd | 1130 | } |
aeaa3d9e | 1131 | debug("private host key: #%d type %d %s", i, key->type, |
1132 | key_type(key)); | |
fa08c86b | 1133 | } |
1134 | if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) { | |
bbe88b6d | 1135 | logit("Disabling protocol version 1. Could not load host key"); |
fa08c86b | 1136 | options.protocol &= ~SSH_PROTO_1; |
1137 | } | |
1138 | if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) { | |
bbe88b6d | 1139 | logit("Disabling protocol version 2. Could not load host key"); |
fa08c86b | 1140 | options.protocol &= ~SSH_PROTO_2; |
a306f2dd | 1141 | } |
6a416424 | 1142 | if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) { |
bbe88b6d | 1143 | logit("sshd: no hostkeys available -- exiting."); |
5260325f | 1144 | exit(1); |
1145 | } | |
5260325f | 1146 | |
a306f2dd | 1147 | /* Check certain values for sanity. */ |
1148 | if (options.protocol & SSH_PROTO_1) { | |
1149 | if (options.server_key_bits < 512 || | |
1150 | options.server_key_bits > 32768) { | |
1151 | fprintf(stderr, "Bad server key size.\n"); | |
1152 | exit(1); | |
1153 | } | |
1154 | /* | |
1155 | * Check that server and host key lengths differ sufficiently. This | |
1156 | * is necessary to make double encryption work with rsaref. Oh, I | |
1157 | * hate software patents. I dont know if this can go? Niels | |
1158 | */ | |
1159 | if (options.server_key_bits > | |
e424e241 | 1160 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) - |
1161 | SSH_KEY_BITS_RESERVED && options.server_key_bits < | |
1162 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + | |
1163 | SSH_KEY_BITS_RESERVED) { | |
a306f2dd | 1164 | options.server_key_bits = |
e424e241 | 1165 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + |
1166 | SSH_KEY_BITS_RESERVED; | |
a306f2dd | 1167 | debug("Forcing server key to %d bits to make it differ from host key.", |
1168 | options.server_key_bits); | |
1169 | } | |
1170 | } | |
1171 | ||
3cc54fbb | 1172 | if (use_privsep) { |
1173 | struct passwd *pw; | |
1174 | struct stat st; | |
1175 | ||
1176 | if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) | |
1177 | fatal("Privilege separation user %s does not exist", | |
1178 | SSH_PRIVSEP_USER); | |
1179 | if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) || | |
1180 | (S_ISDIR(st.st_mode) == 0)) | |
1181 | fatal("Missing privilege separation directory: %s", | |
1182 | _PATH_PRIVSEP_CHROOT_DIR); | |
b9b82dab | 1183 | |
1184 | #ifdef HAVE_CYGWIN | |
1185 | if (check_ntsec(_PATH_PRIVSEP_CHROOT_DIR) && | |
1186 | (st.st_uid != getuid () || | |
1187 | (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)) | |
1188 | #else | |
a56313d7 | 1189 | if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0) |
b9b82dab | 1190 | #endif |
5f021474 | 1191 | fatal("%s must be owned by root and not group or " |
1192 | "world-writable.", _PATH_PRIVSEP_CHROOT_DIR); | |
3cc54fbb | 1193 | } |
1194 | ||
f87f09aa | 1195 | /* Configuration looks good, so exit if in test mode. */ |
1196 | if (test_flag) | |
1197 | exit(0); | |
1198 | ||
018a5ea3 | 1199 | /* |
1200 | * Clear out any supplemental groups we may have inherited. This | |
1201 | * prevents inadvertent creation of files with bad modes (in the | |
aff51935 | 1202 | * portable version at least, it's certainly possible for PAM |
1203 | * to create a file, and we can't control the code in every | |
018a5ea3 | 1204 | * module which might be used). |
1205 | */ | |
1206 | if (setgroups(0, NULL) < 0) | |
1207 | debug("setgroups() failed: %.200s", strerror(errno)); | |
1208 | ||
b9a549d7 | 1209 | if (rexec_flag) { |
1210 | rexec_argv = xmalloc(sizeof(char *) * (rexec_argc + 2)); | |
1211 | for (i = 0; i < rexec_argc; i++) { | |
1212 | debug("rexec_argv[%d]='%s'", i, saved_argv[i]); | |
1213 | rexec_argv[i] = saved_argv[i]; | |
1214 | } | |
1215 | rexec_argv[rexec_argc] = "-R"; | |
1216 | rexec_argv[rexec_argc + 1] = NULL; | |
1217 | } | |
1218 | ||
a306f2dd | 1219 | /* Initialize the log (it is reinitialized below in case we forked). */ |
25c31d49 | 1220 | if (debug_flag && (!inetd_flag || rexeced_flag)) |
5260325f | 1221 | log_stderr = 1; |
1fe6a48f | 1222 | log_init(__progname, options.log_level, options.log_facility, log_stderr); |
5260325f | 1223 | |
a306f2dd | 1224 | /* |
1225 | * If not in debugging mode, and not started from inetd, disconnect | |
1226 | * from the controlling terminal, and fork. The original process | |
1227 | * exits. | |
1228 | */ | |
0b6fbf03 | 1229 | if (!(debug_flag || inetd_flag || no_daemon_flag)) { |
8efc0c15 | 1230 | #ifdef TIOCNOTTY |
5260325f | 1231 | int fd; |
8efc0c15 | 1232 | #endif /* TIOCNOTTY */ |
5260325f | 1233 | if (daemon(0, 0) < 0) |
1234 | fatal("daemon() failed: %.200s", strerror(errno)); | |
1235 | ||
1236 | /* Disconnect from the controlling tty. */ | |
8efc0c15 | 1237 | #ifdef TIOCNOTTY |
5ca51e19 | 1238 | fd = open(_PATH_TTY, O_RDWR | O_NOCTTY); |
5260325f | 1239 | if (fd >= 0) { |
1240 | (void) ioctl(fd, TIOCNOTTY, NULL); | |
1241 | close(fd); | |
1242 | } | |
8efc0c15 | 1243 | #endif /* TIOCNOTTY */ |
8efc0c15 | 1244 | } |
5260325f | 1245 | /* Reinitialize the log (because of the fork above). */ |
1fe6a48f | 1246 | log_init(__progname, options.log_level, options.log_facility, log_stderr); |
5260325f | 1247 | |
5260325f | 1248 | /* Initialize the random number generator. */ |
1249 | arc4random_stir(); | |
1250 | ||
1251 | /* Chdir to the root directory so that the current disk can be | |
1252 | unmounted if desired. */ | |
1253 | chdir("/"); | |
184eed6a | 1254 | |
1d3c30db | 1255 | /* ignore SIGPIPE */ |
1256 | signal(SIGPIPE, SIG_IGN); | |
5260325f | 1257 | |
5260325f | 1258 | /* Start listening for a socket, unless started from inetd. */ |
1259 | if (inetd_flag) { | |
b9a549d7 | 1260 | int fd; |
1261 | ||
4c8722d9 | 1262 | startup_pipe = -1; |
b9a549d7 | 1263 | if (rexeced_flag) { |
b250e837 | 1264 | close(REEXEC_CONFIG_PASS_FD); |
b9a549d7 | 1265 | sock_in = sock_out = dup(STDIN_FILENO); |
1266 | if (!debug_flag) { | |
b250e837 | 1267 | startup_pipe = dup(REEXEC_STARTUP_PIPE_FD); |
1268 | close(REEXEC_STARTUP_PIPE_FD); | |
b9a549d7 | 1269 | } |
1270 | } else { | |
1271 | sock_in = dup(STDIN_FILENO); | |
1272 | sock_out = dup(STDOUT_FILENO); | |
1273 | } | |
a306f2dd | 1274 | /* |
1275 | * We intentionally do not close the descriptors 0, 1, and 2 | |
b9a549d7 | 1276 | * as our code for setting the descriptors won't work if |
a306f2dd | 1277 | * ttyfd happens to be one of those. |
1278 | */ | |
b9a549d7 | 1279 | if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { |
1280 | dup2(fd, STDIN_FILENO); | |
1281 | dup2(fd, STDOUT_FILENO); | |
1282 | if (fd > STDOUT_FILENO) | |
1283 | close(fd); | |
1284 | } | |
5260325f | 1285 | debug("inetd sockets after dupping: %d, %d", sock_in, sock_out); |
b9a549d7 | 1286 | if ((options.protocol & SSH_PROTO_1) && |
1287 | sensitive_data.server_key == NULL) | |
cb7bd922 | 1288 | generate_ephemeral_server_key(); |
5260325f | 1289 | } else { |
48e671d5 | 1290 | for (ai = options.listen_addrs; ai; ai = ai->ai_next) { |
1291 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) | |
1292 | continue; | |
1293 | if (num_listen_socks >= MAX_LISTEN_SOCKS) | |
1294 | fatal("Too many listen sockets. " | |
1295 | "Enlarge MAX_LISTEN_SOCKS"); | |
945a9853 | 1296 | if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen, |
48e671d5 | 1297 | ntop, sizeof(ntop), strport, sizeof(strport), |
945a9853 | 1298 | NI_NUMERICHOST|NI_NUMERICSERV)) != 0) { |
1299 | error("getnameinfo failed: %.100s", | |
1300 | (ret != EAI_SYSTEM) ? gai_strerror(ret) : | |
1301 | strerror(errno)); | |
48e671d5 | 1302 | continue; |
1303 | } | |
1304 | /* Create socket for listening. */ | |
3e131a6d | 1305 | listen_sock = socket(ai->ai_family, ai->ai_socktype, |
1306 | ai->ai_protocol); | |
48e671d5 | 1307 | if (listen_sock < 0) { |
1308 | /* kernel may not support ipv6 */ | |
1309 | verbose("socket: %.100s", strerror(errno)); | |
1310 | continue; | |
1311 | } | |
170694d7 | 1312 | if (set_nonblock(listen_sock) == -1) { |
a666e3b1 | 1313 | close(listen_sock); |
1314 | continue; | |
1315 | } | |
48e671d5 | 1316 | /* |
facfd613 | 1317 | * Set socket options. |
1318 | * Allow local port reuse in TIME_WAIT. | |
48e671d5 | 1319 | */ |
facfd613 | 1320 | if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR, |
1321 | &on, sizeof(on)) == -1) | |
1322 | error("setsockopt SO_REUSEADDR: %s", strerror(errno)); | |
48e671d5 | 1323 | |
1324 | debug("Bind to port %s on %s.", strport, ntop); | |
1325 | ||
1326 | /* Bind the socket to the desired port. */ | |
32ced054 | 1327 | if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) { |
1328 | if (!ai->ai_next) | |
1329 | error("Bind to port %s on %s failed: %.200s.", | |
1330 | strport, ntop, strerror(errno)); | |
48e671d5 | 1331 | close(listen_sock); |
1332 | continue; | |
1333 | } | |
1334 | listen_socks[num_listen_socks] = listen_sock; | |
1335 | num_listen_socks++; | |
1336 | ||
1337 | /* Start listening on the port. */ | |
fce39749 | 1338 | if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0) |
9f513268 | 1339 | fatal("listen on [%s]:%s: %.100s", |
1340 | ntop, strport, strerror(errno)); | |
1341 | logit("Server listening on %s port %s.", ntop, strport); | |
5260325f | 1342 | } |
48e671d5 | 1343 | freeaddrinfo(options.listen_addrs); |
1344 | ||
1345 | if (!num_listen_socks) | |
1346 | fatal("Cannot bind any address."); | |
1347 | ||
3aca00a3 | 1348 | if (options.protocol & SSH_PROTO_1) |
1349 | generate_ephemeral_server_key(); | |
1350 | ||
1351 | /* | |
1352 | * Arrange to restart on SIGHUP. The handler needs | |
1353 | * listen_sock. | |
1354 | */ | |
1355 | signal(SIGHUP, sighup_handler); | |
1356 | ||
1357 | signal(SIGTERM, sigterm_handler); | |
1358 | signal(SIGQUIT, sigterm_handler); | |
1359 | ||
1360 | /* Arrange SIGCHLD to be caught. */ | |
1361 | signal(SIGCHLD, main_sigchld_handler); | |
1362 | ||
1363 | /* Write out the pid file after the sigterm handler is setup */ | |
5260325f | 1364 | if (!debug_flag) { |
aa3378df | 1365 | /* |
97fb6912 | 1366 | * Record our pid in /var/run/sshd.pid to make it |
1367 | * easier to kill the correct sshd. We don't want to | |
1368 | * do this before the bind above because the bind will | |
aa3378df | 1369 | * fail if there already is a daemon, and this will |
1370 | * overwrite any old pid in the file. | |
1371 | */ | |
3c62e7eb | 1372 | f = fopen(options.pid_file, "wb"); |
71b9ced0 | 1373 | if (f == NULL) { |
1374 | error("Couldn't create pid file \"%s\": %s", | |
1375 | options.pid_file, strerror(errno)); | |
1376 | } else { | |
c457707e | 1377 | fprintf(f, "%ld\n", (long) getpid()); |
5260325f | 1378 | fclose(f); |
1379 | } | |
8efc0c15 | 1380 | } |
5260325f | 1381 | |
48e671d5 | 1382 | /* setup fd set for listen */ |
089fbbd2 | 1383 | fdset = NULL; |
48e671d5 | 1384 | maxfd = 0; |
1385 | for (i = 0; i < num_listen_socks; i++) | |
1386 | if (listen_socks[i] > maxfd) | |
1387 | maxfd = listen_socks[i]; | |
089fbbd2 | 1388 | /* pipes connected to unauthenticated childs */ |
1389 | startup_pipes = xmalloc(options.max_startups * sizeof(int)); | |
1390 | for (i = 0; i < options.max_startups; i++) | |
1391 | startup_pipes[i] = -1; | |
48e671d5 | 1392 | |
aa3378df | 1393 | /* |
1394 | * Stay listening for connections until the system crashes or | |
1395 | * the daemon is killed with a signal. | |
1396 | */ | |
5260325f | 1397 | for (;;) { |
1398 | if (received_sighup) | |
1399 | sighup_restart(); | |
089fbbd2 | 1400 | if (fdset != NULL) |
1401 | xfree(fdset); | |
b5c334cc | 1402 | fdsetsz = howmany(maxfd+1, NFDBITS) * sizeof(fd_mask); |
089fbbd2 | 1403 | fdset = (fd_set *)xmalloc(fdsetsz); |
48e671d5 | 1404 | memset(fdset, 0, fdsetsz); |
089fbbd2 | 1405 | |
48e671d5 | 1406 | for (i = 0; i < num_listen_socks; i++) |
1407 | FD_SET(listen_socks[i], fdset); | |
089fbbd2 | 1408 | for (i = 0; i < options.max_startups; i++) |
1409 | if (startup_pipes[i] != -1) | |
1410 | FD_SET(startup_pipes[i], fdset); | |
1411 | ||
1412 | /* Wait in select until there is a connection. */ | |
59c97189 | 1413 | ret = select(maxfd+1, fdset, NULL, NULL, NULL); |
1414 | if (ret < 0 && errno != EINTR) | |
1415 | error("select: %.100s", strerror(errno)); | |
c9130033 | 1416 | if (received_sigterm) { |
bbe88b6d | 1417 | logit("Received signal %d; terminating.", |
010f9726 | 1418 | (int) received_sigterm); |
c9130033 | 1419 | close_listen_socks(); |
1420 | unlink(options.pid_file); | |
1421 | exit(255); | |
1422 | } | |
59c97189 | 1423 | if (key_used && key_do_regen) { |
cb7bd922 | 1424 | generate_ephemeral_server_key(); |
59c97189 | 1425 | key_used = 0; |
1426 | key_do_regen = 0; | |
48e671d5 | 1427 | } |
59c97189 | 1428 | if (ret < 0) |
1429 | continue; | |
1430 | ||
089fbbd2 | 1431 | for (i = 0; i < options.max_startups; i++) |
1432 | if (startup_pipes[i] != -1 && | |
1433 | FD_ISSET(startup_pipes[i], fdset)) { | |
1434 | /* | |
1435 | * the read end of the pipe is ready | |
1436 | * if the child has closed the pipe | |
8abcdba4 | 1437 | * after successful authentication |
089fbbd2 | 1438 | * or if the child has died |
1439 | */ | |
1440 | close(startup_pipes[i]); | |
1441 | startup_pipes[i] = -1; | |
1442 | startups--; | |
1443 | } | |
48e671d5 | 1444 | for (i = 0; i < num_listen_socks; i++) { |
1445 | if (!FD_ISSET(listen_socks[i], fdset)) | |
5260325f | 1446 | continue; |
089fbbd2 | 1447 | fromlen = sizeof(from); |
1448 | newsock = accept(listen_socks[i], (struct sockaddr *)&from, | |
1449 | &fromlen); | |
1450 | if (newsock < 0) { | |
1451 | if (errno != EINTR && errno != EWOULDBLOCK) | |
1452 | error("accept: %.100s", strerror(errno)); | |
1453 | continue; | |
1454 | } | |
170694d7 | 1455 | if (unset_nonblock(newsock) == -1) { |
a666e3b1 | 1456 | close(newsock); |
1457 | continue; | |
1458 | } | |
c345cf9d | 1459 | if (drop_connection(startups) == 1) { |
1460 | debug("drop connection #%d", startups); | |
089fbbd2 | 1461 | close(newsock); |
1462 | continue; | |
1463 | } | |
1464 | if (pipe(startup_p) == -1) { | |
1465 | close(newsock); | |
1466 | continue; | |
1467 | } | |
1468 | ||
b9a549d7 | 1469 | if (rexec_flag && socketpair(AF_UNIX, |
1470 | SOCK_STREAM, 0, config_s) == -1) { | |
1471 | error("reexec socketpair: %s", | |
1472 | strerror(errno)); | |
1473 | close(newsock); | |
1474 | close(startup_p[0]); | |
1475 | close(startup_p[1]); | |
1476 | continue; | |
1477 | } | |
1478 | ||
089fbbd2 | 1479 | for (j = 0; j < options.max_startups; j++) |
1480 | if (startup_pipes[j] == -1) { | |
1481 | startup_pipes[j] = startup_p[0]; | |
1482 | if (maxfd < startup_p[0]) | |
1483 | maxfd = startup_p[0]; | |
1484 | startups++; | |
1485 | break; | |
1486 | } | |
2b87da3b | 1487 | |
aa3378df | 1488 | /* |
089fbbd2 | 1489 | * Got connection. Fork a child to handle it, unless |
1490 | * we are in debugging mode. | |
aa3378df | 1491 | */ |
089fbbd2 | 1492 | if (debug_flag) { |
aa3378df | 1493 | /* |
089fbbd2 | 1494 | * In debugging mode. Close the listening |
1495 | * socket, and start processing the | |
1496 | * connection without forking. | |
aa3378df | 1497 | */ |
089fbbd2 | 1498 | debug("Server will not fork when running in debugging mode."); |
48e671d5 | 1499 | close_listen_socks(); |
5260325f | 1500 | sock_in = newsock; |
1501 | sock_out = newsock; | |
b9a549d7 | 1502 | close(startup_p[0]); |
1503 | close(startup_p[1]); | |
5540ea9b | 1504 | startup_pipe = -1; |
3f7a7e4a | 1505 | pid = getpid(); |
b9a549d7 | 1506 | if (rexec_flag) { |
1507 | send_rexec_state(config_s[0], | |
1508 | &cfg); | |
1509 | close(config_s[0]); | |
1510 | } | |
5260325f | 1511 | break; |
089fbbd2 | 1512 | } else { |
1513 | /* | |
1514 | * Normal production daemon. Fork, and have | |
1515 | * the child process the connection. The | |
1516 | * parent continues listening. | |
1517 | */ | |
1518 | if ((pid = fork()) == 0) { | |
1519 | /* | |
1520 | * Child. Close the listening and max_startup | |
1521 | * sockets. Start using the accepted socket. | |
1522 | * Reinitialize logging (since our pid has | |
1523 | * changed). We break out of the loop to handle | |
1524 | * the connection. | |
1525 | */ | |
1526 | startup_pipe = startup_p[1]; | |
7ace8c3b | 1527 | close_startup_pipes(); |
089fbbd2 | 1528 | close_listen_socks(); |
1529 | sock_in = newsock; | |
1530 | sock_out = newsock; | |
1fe6a48f | 1531 | log_init(__progname, options.log_level, options.log_facility, log_stderr); |
9216f89c | 1532 | if (rexec_flag) |
1533 | close(config_s[0]); | |
089fbbd2 | 1534 | break; |
1535 | } | |
5260325f | 1536 | } |
5260325f | 1537 | |
089fbbd2 | 1538 | /* Parent. Stay in the loop. */ |
1539 | if (pid < 0) | |
1540 | error("fork: %.100s", strerror(errno)); | |
1541 | else | |
c457707e | 1542 | debug("Forked child %ld.", (long)pid); |
5260325f | 1543 | |
089fbbd2 | 1544 | close(startup_p[1]); |
5260325f | 1545 | |
b9a549d7 | 1546 | if (rexec_flag) { |
1547 | send_rexec_state(config_s[0], &cfg); | |
1548 | close(config_s[0]); | |
1549 | close(config_s[1]); | |
1550 | } | |
1551 | ||
089fbbd2 | 1552 | /* Mark that the key has been used (it was "given" to the child). */ |
59c97189 | 1553 | if ((options.protocol & SSH_PROTO_1) && |
1554 | key_used == 0) { | |
1555 | /* Schedule server key regeneration alarm. */ | |
f00d1f78 | 1556 | signal(SIGALRM, key_regeneration_alarm); |
59c97189 | 1557 | alarm(options.key_regeneration_time); |
1558 | key_used = 1; | |
1559 | } | |
5260325f | 1560 | |
089fbbd2 | 1561 | arc4random_stir(); |
1562 | ||
1563 | /* Close the new socket (the child is now taking care of it). */ | |
1564 | close(newsock); | |
1565 | } | |
48e671d5 | 1566 | /* child process check (or debug mode) */ |
1567 | if (num_listen_socks < 0) | |
1568 | break; | |
5260325f | 1569 | } |
1570 | } | |
8efc0c15 | 1571 | |
5260325f | 1572 | /* This is the child processing a new connection. */ |
cc120685 | 1573 | setproctitle("%s", "[accepted]"); |
5260325f | 1574 | |
8b758bd2 | 1575 | /* |
1576 | * Create a new session and process group since the 4.4BSD | |
1577 | * setlogin() affects the entire process group. We don't | |
1578 | * want the child to be able to affect the parent. | |
1579 | */ | |
1580 | #if !defined(SSHD_ACQUIRES_CTTY) | |
1581 | /* | |
1582 | * If setsid is called, on some platforms sshd will later acquire a | |
1583 | * controlling terminal which will result in "could not set | |
1584 | * controlling tty" errors. | |
1585 | */ | |
1586 | if (!debug_flag && !inetd_flag && setsid() < 0) | |
1587 | error("setsid: %.100s", strerror(errno)); | |
1588 | #endif | |
1589 | ||
b9a549d7 | 1590 | if (rexec_flag) { |
1591 | int fd; | |
1592 | ||
b250e837 | 1593 | debug("rexec start in %d out %d newsock %d pipe %d sock %d", |
1594 | sock_in, sock_out, newsock, startup_pipe, config_s[0]); | |
b9a549d7 | 1595 | dup2(newsock, STDIN_FILENO); |
1596 | dup2(STDIN_FILENO, STDOUT_FILENO); | |
1597 | if (startup_pipe == -1) | |
b250e837 | 1598 | close(REEXEC_STARTUP_PIPE_FD); |
b9a549d7 | 1599 | else |
b250e837 | 1600 | dup2(startup_pipe, REEXEC_STARTUP_PIPE_FD); |
b9a549d7 | 1601 | |
b250e837 | 1602 | dup2(config_s[1], REEXEC_CONFIG_PASS_FD); |
b9a549d7 | 1603 | close(config_s[1]); |
ad148c04 | 1604 | if (startup_pipe != -1) |
1605 | close(startup_pipe); | |
b250e837 | 1606 | |
b9a549d7 | 1607 | execv(rexec_argv[0], rexec_argv); |
1608 | ||
1609 | /* Reexec has failed, fall back and continue */ | |
1610 | error("rexec of %s failed: %s", rexec_argv[0], strerror(errno)); | |
b250e837 | 1611 | recv_rexec_state(REEXEC_CONFIG_PASS_FD, NULL); |
b9a549d7 | 1612 | log_init(__progname, options.log_level, |
1613 | options.log_facility, log_stderr); | |
1614 | ||
1615 | /* Clean up fds */ | |
b250e837 | 1616 | startup_pipe = REEXEC_STARTUP_PIPE_FD; |
b9a549d7 | 1617 | close(config_s[1]); |
b250e837 | 1618 | close(REEXEC_CONFIG_PASS_FD); |
1619 | newsock = sock_out = sock_in = dup(STDIN_FILENO); | |
b9a549d7 | 1620 | if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { |
1621 | dup2(fd, STDIN_FILENO); | |
1622 | dup2(fd, STDOUT_FILENO); | |
1623 | if (fd > STDERR_FILENO) | |
1624 | close(fd); | |
1625 | } | |
b250e837 | 1626 | debug("rexec cleanup in %d out %d newsock %d pipe %d sock %d", |
1627 | sock_in, sock_out, newsock, startup_pipe, config_s[0]); | |
b9a549d7 | 1628 | } |
1629 | ||
aa3378df | 1630 | /* |
1631 | * Disable the key regeneration alarm. We will not regenerate the | |
1632 | * key since we are no longer in a position to give it to anyone. We | |
1633 | * will not restart on SIGHUP since it no longer makes sense. | |
1634 | */ | |
5260325f | 1635 | alarm(0); |
1636 | signal(SIGALRM, SIG_DFL); | |
1637 | signal(SIGHUP, SIG_DFL); | |
1638 | signal(SIGTERM, SIG_DFL); | |
1639 | signal(SIGQUIT, SIG_DFL); | |
1640 | signal(SIGCHLD, SIG_DFL); | |
9aaf9be4 | 1641 | signal(SIGINT, SIG_DFL); |
5260325f | 1642 | |
aa3378df | 1643 | /* |
1644 | * Register our connection. This turns encryption off because we do | |
1645 | * not have a key. | |
1646 | */ | |
5260325f | 1647 | packet_set_connection(sock_in, sock_out); |
07200973 | 1648 | packet_set_server(); |
5260325f | 1649 | |
7c3bc5a2 | 1650 | /* Set SO_KEEPALIVE if requested. */ |
1651 | if (options.tcp_keep_alive && packet_connection_is_on_socket() && | |
1652 | setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) < 0) | |
1653 | error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); | |
1654 | ||
29798ed0 | 1655 | if ((remote_port = get_remote_port()) < 0) { |
1656 | debug("get_remote_port failed"); | |
1657 | cleanup_exit(255); | |
1658 | } | |
3a85986d | 1659 | |
1660 | /* | |
1661 | * We use get_canonical_hostname with usedns = 0 instead of | |
1662 | * get_remote_ipaddr here so IP options will be checked. | |
1663 | */ | |
1664 | remote_ip = get_canonical_hostname(0); | |
5260325f | 1665 | |
6039eeef | 1666 | #ifdef SSH_AUDIT_EVENTS |
c00e4d75 | 1667 | audit_connection_from(remote_ip, remote_port); |
1668 | #endif | |
5260325f | 1669 | #ifdef LIBWRAP |
ac28afd8 | 1670 | /* Check whether logins are denied from this host. */ |
33e5359c | 1671 | if (packet_connection_is_on_socket()) { |
5260325f | 1672 | struct request_info req; |
8efc0c15 | 1673 | |
8fbc356d | 1674 | request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0); |
5260325f | 1675 | fromhost(&req); |
8efc0c15 | 1676 | |
5260325f | 1677 | if (!hosts_access(&req)) { |
ac28afd8 | 1678 | debug("Connection refused by tcp wrapper"); |
563834bb | 1679 | refuse(&req); |
ac28afd8 | 1680 | /* NOTREACHED */ |
1681 | fatal("libwrap refuse returns"); | |
5260325f | 1682 | } |
8efc0c15 | 1683 | } |
48e671d5 | 1684 | #endif /* LIBWRAP */ |
ac28afd8 | 1685 | |
5260325f | 1686 | /* Log the connection. */ |
1687 | verbose("Connection from %.500s port %d", remote_ip, remote_port); | |
8efc0c15 | 1688 | |
aa3378df | 1689 | /* |
7b9b0103 | 1690 | * We don't want to listen forever unless the other side |
aa3378df | 1691 | * successfully authenticates itself. So we set up an alarm which is |
1692 | * cleared after successful authentication. A limit of zero | |
7b9b0103 | 1693 | * indicates no limit. Note that we don't set the alarm in debugging |
aa3378df | 1694 | * mode; it is just annoying to have the server exit just when you |
1695 | * are about to discover the bug. | |
1696 | */ | |
f00d1f78 | 1697 | signal(SIGALRM, grace_alarm_handler); |
5260325f | 1698 | if (!debug_flag) |
1699 | alarm(options.login_grace_time); | |
1700 | ||
7368a6c8 | 1701 | sshd_exchange_identification(sock_in, sock_out); |
0598d99d | 1702 | |
5260325f | 1703 | packet_set_nonblocking(); |
1704 | ||
2362db19 | 1705 | /* allocate authentication context */ |
1706 | authctxt = xmalloc(sizeof(*authctxt)); | |
1707 | memset(authctxt, 0, sizeof(*authctxt)); | |
1708 | ||
1b394137 | 1709 | authctxt->loginmsg = &loginmsg; |
1710 | ||
2362db19 | 1711 | /* XXX global for cleanup, access from other modules */ |
1712 | the_authctxt = authctxt; | |
1713 | ||
022487ce | 1714 | /* prepare buffer to collect messages to display to user after login */ |
1715 | buffer_init(&loginmsg); | |
1716 | ||
324bf712 | 1717 | if (use_privsep) |
2362db19 | 1718 | if (privsep_preauth(authctxt) == 1) |
324bf712 | 1719 | goto authenticated; |
1853d1ef | 1720 | |
7b2ea3a1 | 1721 | /* perform the key exchange */ |
7b2ea3a1 | 1722 | /* authenticate user and start session */ |
e78a59f5 | 1723 | if (compat20) { |
1724 | do_ssh2_kex(); | |
2362db19 | 1725 | do_authentication2(authctxt); |
e78a59f5 | 1726 | } else { |
1727 | do_ssh1_kex(); | |
2362db19 | 1728 | do_authentication(authctxt); |
e78a59f5 | 1729 | } |
324bf712 | 1730 | /* |
1731 | * If we use privilege separation, the unprivileged child transfers | |
1732 | * the current keystate and exits | |
1733 | */ | |
1734 | if (use_privsep) { | |
b5a28cbc | 1735 | mm_send_keystate(pmonitor); |
1853d1ef | 1736 | exit(0); |
324bf712 | 1737 | } |
1853d1ef | 1738 | |
1739 | authenticated: | |
678143bd | 1740 | /* |
1741 | * Cancel the alarm we set to limit the time taken for | |
1742 | * authentication. | |
1743 | */ | |
1744 | alarm(0); | |
1745 | signal(SIGALRM, SIG_DFL); | |
1746 | if (startup_pipe != -1) { | |
1747 | close(startup_pipe); | |
1748 | startup_pipe = -1; | |
1749 | } | |
1750 | ||
6039eeef | 1751 | #ifdef SSH_AUDIT_EVENTS |
1752 | audit_event(SSH_AUTH_SUCCESS); | |
c00e4d75 | 1753 | #endif |
1754 | ||
762715ce | 1755 | /* |
1853d1ef | 1756 | * In privilege separation, we fork another child and prepare |
1757 | * file descriptor passing. | |
1758 | */ | |
1759 | if (use_privsep) { | |
324bf712 | 1760 | privsep_postauth(authctxt); |
1761 | /* the monitor process [priv] will not return */ | |
1853d1ef | 1762 | if (!compat20) |
1763 | destroy_sensitive_data(); | |
1764 | } | |
1b34c1b3 | 1765 | |
2362db19 | 1766 | /* Start session. */ |
1b34c1b3 | 1767 | do_authenticated(authctxt); |
1768 | ||
63284fbb | 1769 | /* The connection has been terminated. */ |
1770 | verbose("Closing connection to %.100s", remote_ip); | |
8efc0c15 | 1771 | |
d94aa2ae | 1772 | #ifdef USE_PAM |
7fceb20d | 1773 | if (options.use_pam) |
1774 | finish_pam(); | |
d94aa2ae | 1775 | #endif /* USE_PAM */ |
8efc0c15 | 1776 | |
2b0c0925 | 1777 | #ifdef SSH_AUDIT_EVENTS |
1778 | PRIVSEP(audit_event(SSH_CONNECTION_CLOSE)); | |
1779 | #endif | |
1780 | ||
5260325f | 1781 | packet_close(); |
1853d1ef | 1782 | |
1783 | if (use_privsep) | |
1784 | mm_terminate(); | |
1785 | ||
5260325f | 1786 | exit(0); |
1787 | } | |
8efc0c15 | 1788 | |
4f08e98d | 1789 | /* |
1790 | * Decrypt session_key_int using our private server key and private host key | |
1791 | * (key with larger modulus first). | |
1792 | */ | |
1853d1ef | 1793 | int |
4f08e98d | 1794 | ssh1_session_key(BIGNUM *session_key_int) |
1795 | { | |
1796 | int rsafail = 0; | |
1797 | ||
1798 | if (BN_cmp(sensitive_data.server_key->rsa->n, sensitive_data.ssh1_host_key->rsa->n) > 0) { | |
1799 | /* Server key has bigger modulus. */ | |
1800 | if (BN_num_bits(sensitive_data.server_key->rsa->n) < | |
1801 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + SSH_KEY_BITS_RESERVED) { | |
1802 | fatal("do_connection: %s: server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d", | |
1803 | get_remote_ipaddr(), | |
1804 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
1805 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), | |
1806 | SSH_KEY_BITS_RESERVED); | |
1807 | } | |
1808 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1809 | sensitive_data.server_key->rsa) <= 0) | |
1810 | rsafail++; | |
1811 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1812 | sensitive_data.ssh1_host_key->rsa) <= 0) | |
1813 | rsafail++; | |
1814 | } else { | |
1815 | /* Host key has bigger modulus (or they are equal). */ | |
1816 | if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) < | |
1817 | BN_num_bits(sensitive_data.server_key->rsa->n) + SSH_KEY_BITS_RESERVED) { | |
1818 | fatal("do_connection: %s: host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d", | |
1819 | get_remote_ipaddr(), | |
1820 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), | |
1821 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
1822 | SSH_KEY_BITS_RESERVED); | |
1823 | } | |
1824 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1825 | sensitive_data.ssh1_host_key->rsa) < 0) | |
1826 | rsafail++; | |
1827 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1828 | sensitive_data.server_key->rsa) < 0) | |
1829 | rsafail++; | |
1830 | } | |
1831 | return (rsafail); | |
1832 | } | |
5260325f | 1833 | /* |
7b2ea3a1 | 1834 | * SSH1 key exchange |
5260325f | 1835 | */ |
396c147e | 1836 | static void |
1e3b8b07 | 1837 | do_ssh1_kex(void) |
8efc0c15 | 1838 | { |
5260325f | 1839 | int i, len; |
46aa2d1f | 1840 | int rsafail = 0; |
5260325f | 1841 | BIGNUM *session_key_int; |
1e3b8b07 | 1842 | u_char session_key[SSH_SESSION_KEY_LENGTH]; |
1843 | u_char cookie[8]; | |
1844 | u_int cipher_type, auth_mask, protocol_flags; | |
7fdc56c5 | 1845 | u_int32_t rnd = 0; |
5260325f | 1846 | |
aa3378df | 1847 | /* |
1848 | * Generate check bytes that the client must send back in the user | |
1849 | * packet in order for it to be accepted; this is used to defy ip | |
1850 | * spoofing attacks. Note that this only works against somebody | |
1851 | * doing IP spoofing from a remote machine; any machine on the local | |
1852 | * network can still see outgoing packets and catch the random | |
1853 | * cookie. This only affects rhosts authentication, and this is one | |
1854 | * of the reasons why it is inherently insecure. | |
1855 | */ | |
5260325f | 1856 | for (i = 0; i < 8; i++) { |
1857 | if (i % 4 == 0) | |
7fdc56c5 | 1858 | rnd = arc4random(); |
1859 | cookie[i] = rnd & 0xff; | |
1860 | rnd >>= 8; | |
5260325f | 1861 | } |
1862 | ||
aa3378df | 1863 | /* |
1864 | * Send our public key. We include in the packet 64 bits of random | |
1865 | * data that must be matched in the reply in order to prevent IP | |
1866 | * spoofing. | |
1867 | */ | |
5260325f | 1868 | packet_start(SSH_SMSG_PUBLIC_KEY); |
1869 | for (i = 0; i < 8; i++) | |
7b2ea3a1 | 1870 | packet_put_char(cookie[i]); |
5260325f | 1871 | |
1872 | /* Store our public server RSA key. */ | |
fa08c86b | 1873 | packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n)); |
1874 | packet_put_bignum(sensitive_data.server_key->rsa->e); | |
1875 | packet_put_bignum(sensitive_data.server_key->rsa->n); | |
5260325f | 1876 | |
1877 | /* Store our public host RSA key. */ | |
fa08c86b | 1878 | packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); |
1879 | packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e); | |
1880 | packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n); | |
5260325f | 1881 | |
1882 | /* Put protocol flags. */ | |
1883 | packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN); | |
1884 | ||
1885 | /* Declare which ciphers we support. */ | |
94ec8c6b | 1886 | packet_put_int(cipher_mask_ssh1(0)); |
5260325f | 1887 | |
1888 | /* Declare supported authentication types. */ | |
1889 | auth_mask = 0; | |
5260325f | 1890 | if (options.rhosts_rsa_authentication) |
1891 | auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA; | |
1892 | if (options.rsa_authentication) | |
1893 | auth_mask |= 1 << SSH_AUTH_RSA; | |
5ba55ada | 1894 | if (options.challenge_response_authentication == 1) |
5260325f | 1895 | auth_mask |= 1 << SSH_AUTH_TIS; |
5260325f | 1896 | if (options.password_authentication) |
1897 | auth_mask |= 1 << SSH_AUTH_PASSWORD; | |
1898 | packet_put_int(auth_mask); | |
1899 | ||
1900 | /* Send the packet and wait for it to be sent. */ | |
1901 | packet_send(); | |
1902 | packet_write_wait(); | |
1903 | ||
fa08c86b | 1904 | debug("Sent %d bit server key and %d bit host key.", |
1905 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
1906 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); | |
5260325f | 1907 | |
1908 | /* Read clients reply (cipher type and session key). */ | |
54a5250f | 1909 | packet_read_expect(SSH_CMSG_SESSION_KEY); |
5260325f | 1910 | |
2d86a6cc | 1911 | /* Get cipher type and check whether we accept this. */ |
5260325f | 1912 | cipher_type = packet_get_char(); |
1913 | ||
94ec8c6b | 1914 | if (!(cipher_mask_ssh1(0) & (1 << cipher_type))) |
2d86a6cc | 1915 | packet_disconnect("Warning: client selects unsupported cipher."); |
1916 | ||
5260325f | 1917 | /* Get check bytes from the packet. These must match those we |
1918 | sent earlier with the public key packet. */ | |
1919 | for (i = 0; i < 8; i++) | |
7b2ea3a1 | 1920 | if (cookie[i] != packet_get_char()) |
5260325f | 1921 | packet_disconnect("IP Spoofing check bytes do not match."); |
1922 | ||
1923 | debug("Encryption type: %.200s", cipher_name(cipher_type)); | |
1924 | ||
1925 | /* Get the encrypted integer. */ | |
b775c6f2 | 1926 | if ((session_key_int = BN_new()) == NULL) |
1927 | fatal("do_ssh1_kex: BN_new failed"); | |
20b279e6 | 1928 | packet_get_bignum(session_key_int); |
5260325f | 1929 | |
5260325f | 1930 | protocol_flags = packet_get_int(); |
1931 | packet_set_protocol_flags(protocol_flags); | |
95500969 | 1932 | packet_check_eom(); |
5260325f | 1933 | |
4f08e98d | 1934 | /* Decrypt session_key_int using host/server keys */ |
1853d1ef | 1935 | rsafail = PRIVSEP(ssh1_session_key(session_key_int)); |
1936 | ||
aa3378df | 1937 | /* |
1938 | * Extract session key from the decrypted integer. The key is in the | |
1939 | * least significant 256 bits of the integer; the first byte of the | |
1940 | * key is in the highest bits. | |
1941 | */ | |
46aa2d1f | 1942 | if (!rsafail) { |
1943 | BN_mask_bits(session_key_int, sizeof(session_key) * 8); | |
1944 | len = BN_num_bytes(session_key_int); | |
2ceb8101 | 1945 | if (len < 0 || (u_int)len > sizeof(session_key)) { |
46aa2d1f | 1946 | error("do_connection: bad session key len from %s: " |
5ca51e19 | 1947 | "session_key_int %d > sizeof(session_key) %lu", |
1948 | get_remote_ipaddr(), len, (u_long)sizeof(session_key)); | |
46aa2d1f | 1949 | rsafail++; |
1950 | } else { | |
1951 | memset(session_key, 0, sizeof(session_key)); | |
1952 | BN_bn2bin(session_key_int, | |
1953 | session_key + sizeof(session_key) - len); | |
00be5382 | 1954 | |
8bbf1fa6 | 1955 | derive_ssh1_session_id( |
f2107e97 | 1956 | sensitive_data.ssh1_host_key->rsa->n, |
8bbf1fa6 | 1957 | sensitive_data.server_key->rsa->n, |
1958 | cookie, session_id); | |
00be5382 | 1959 | /* |
1960 | * Xor the first 16 bytes of the session key with the | |
1961 | * session id. | |
1962 | */ | |
1963 | for (i = 0; i < 16; i++) | |
1964 | session_key[i] ^= session_id[i]; | |
46aa2d1f | 1965 | } |
1966 | } | |
1967 | if (rsafail) { | |
00be5382 | 1968 | int bytes = BN_num_bytes(session_key_int); |
f6b1ba8f | 1969 | u_char *buf = xmalloc(bytes); |
00be5382 | 1970 | MD5_CTX md; |
1971 | ||
bbe88b6d | 1972 | logit("do_connection: generating a fake encryption key"); |
00be5382 | 1973 | BN_bn2bin(session_key_int, buf); |
1974 | MD5_Init(&md); | |
1975 | MD5_Update(&md, buf, bytes); | |
1976 | MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); | |
1977 | MD5_Final(session_key, &md); | |
1978 | MD5_Init(&md); | |
1979 | MD5_Update(&md, session_key, 16); | |
1980 | MD5_Update(&md, buf, bytes); | |
1981 | MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); | |
1982 | MD5_Final(session_key + 16, &md); | |
1983 | memset(buf, 0, bytes); | |
1984 | xfree(buf); | |
0572fe75 | 1985 | for (i = 0; i < 16; i++) |
1986 | session_id[i] = session_key[i] ^ session_key[i + 16]; | |
46aa2d1f | 1987 | } |
1853d1ef | 1988 | /* Destroy the private and public keys. No longer. */ |
63284fbb | 1989 | destroy_sensitive_data(); |
00be5382 | 1990 | |
1853d1ef | 1991 | if (use_privsep) |
1992 | mm_ssh1_session_id(session_id); | |
1993 | ||
7b2ea3a1 | 1994 | /* Destroy the decrypted integer. It is no longer needed. */ |
1995 | BN_clear_free(session_key_int); | |
1996 | ||
5260325f | 1997 | /* Set the session key. From this on all communications will be encrypted. */ |
1998 | packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type); | |
1999 | ||
2000 | /* Destroy our copy of the session key. It is no longer needed. */ | |
2001 | memset(session_key, 0, sizeof(session_key)); | |
2002 | ||
2003 | debug("Received session key; encryption turned on."); | |
2004 | ||
c242fc96 | 2005 | /* Send an acknowledgment packet. Note that this packet is sent encrypted. */ |
5260325f | 2006 | packet_start(SSH_SMSG_SUCCESS); |
2007 | packet_send(); | |
2008 | packet_write_wait(); | |
5260325f | 2009 | } |
e78a59f5 | 2010 | |
2011 | /* | |
2012 | * SSH2 key exchange: diffie-hellman-group1-sha1 | |
2013 | */ | |
396c147e | 2014 | static void |
1e3b8b07 | 2015 | do_ssh2_kex(void) |
e78a59f5 | 2016 | { |
e78a59f5 | 2017 | Kex *kex; |
e78a59f5 | 2018 | |
a8be9f80 | 2019 | if (options.ciphers != NULL) { |
6ae2364d | 2020 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = |
a8be9f80 | 2021 | myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; |
2022 | } | |
1ad64a93 | 2023 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = |
2024 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]); | |
2025 | myproposal[PROPOSAL_ENC_ALGS_STOC] = | |
2026 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); | |
2027 | ||
b2552997 | 2028 | if (options.macs != NULL) { |
2029 | myproposal[PROPOSAL_MAC_ALGS_CTOS] = | |
2030 | myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; | |
2031 | } | |
07200973 | 2032 | if (options.compression == COMP_NONE) { |
636f76ca | 2033 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = |
2034 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "none"; | |
07200973 | 2035 | } else if (options.compression == COMP_DELAYED) { |
2036 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = | |
2037 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com"; | |
636f76ca | 2038 | } |
07200973 | 2039 | |
fa08c86b | 2040 | myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = list_hostkey_types(); |
2041 | ||
7a37c112 | 2042 | /* start key exchange */ |
d8ee838b | 2043 | kex = kex_setup(myproposal); |
98a58eda | 2044 | kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server; |
41e5bd9a | 2045 | kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server; |
98a58eda | 2046 | kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; |
2ff8003a | 2047 | kex->kex[KEX_DH_GEX_SHA256] = kexgex_server; |
a5c9ffdb | 2048 | kex->server = 1; |
2049 | kex->client_version_string=client_version_string; | |
2050 | kex->server_version_string=server_version_string; | |
2051 | kex->load_host_key=&get_hostkey_by_type; | |
1853d1ef | 2052 | kex->host_key_index=&get_hostkey_index; |
94ec8c6b | 2053 | |
7a37c112 | 2054 | xxx_kex = kex; |
2055 | ||
c422989b | 2056 | dispatch_run(DISPATCH_BLOCK, &kex->done, kex); |
94ec8c6b | 2057 | |
d1ac6175 | 2058 | session_id2 = kex->session_id; |
2059 | session_id2_len = kex->session_id_len; | |
2060 | ||
94ec8c6b | 2061 | #ifdef DEBUG_KEXDH |
2062 | /* send 1st encrypted/maced/compressed message */ | |
2063 | packet_start(SSH2_MSG_IGNORE); | |
2064 | packet_put_cstring("markus"); | |
2065 | packet_send(); | |
2066 | packet_write_wait(); | |
2067 | #endif | |
a5c9ffdb | 2068 | debug("KEX done"); |
e78a59f5 | 2069 | } |
2362db19 | 2070 | |
2071 | /* server specific fatal cleanup */ | |
2072 | void | |
2073 | cleanup_exit(int i) | |
2074 | { | |
2075 | if (the_authctxt) | |
2076 | do_cleanup(the_authctxt); | |
6039eeef | 2077 | #ifdef SSH_AUDIT_EVENTS |
c00e4d75 | 2078 | /* done after do_cleanup so it can cancel the PAM auth 'thread' */ |
2079 | if (!use_privsep || mm_is_monitor()) | |
6039eeef | 2080 | audit_event(SSH_CONNECTION_ABANDON); |
c00e4d75 | 2081 | #endif |
2362db19 | 2082 | _exit(i); |
2083 | } |