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c8dfff33 | 1 | /* $OpenBSD: sshd.c,v 1.338 2006/07/12 22:28:52 stevesk Exp $ */ |
8efc0c15 | 2 | /* |
5260325f | 3 | * Author: Tatu Ylonen <ylo@cs.hut.fi> |
4 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland | |
5 | * All rights reserved | |
bcbf86ec | 6 | * This program is the ssh daemon. It listens for connections from clients, |
7 | * and performs authentication, executes use commands or shell, and forwards | |
5260325f | 8 | * information to/from the application to the user client over an encrypted |
bcbf86ec | 9 | * connection. This can also handle forwarding of X11, TCP/IP, and |
10 | * authentication agent connections. | |
e78a59f5 | 11 | * |
bcbf86ec | 12 | * As far as I am concerned, the code I have written for this software |
13 | * can be used freely for any purpose. Any derived versions of this | |
14 | * software must be clearly marked as such, and if the derived work is | |
15 | * incompatible with the protocol description in the RFC file, it must be | |
16 | * called by a name other than "ssh" or "Secure Shell". | |
17 | * | |
18 | * SSH2 implementation: | |
1853d1ef | 19 | * Privilege Separation: |
bcbf86ec | 20 | * |
1853d1ef | 21 | * Copyright (c) 2000, 2001, 2002 Markus Friedl. All rights reserved. |
22 | * Copyright (c) 2002 Niels Provos. All rights reserved. | |
bcbf86ec | 23 | * |
24 | * Redistribution and use in source and binary forms, with or without | |
25 | * modification, are permitted provided that the following conditions | |
26 | * are met: | |
27 | * 1. Redistributions of source code must retain the above copyright | |
28 | * notice, this list of conditions and the following disclaimer. | |
29 | * 2. Redistributions in binary form must reproduce the above copyright | |
30 | * notice, this list of conditions and the following disclaimer in the | |
31 | * documentation and/or other materials provided with the distribution. | |
32 | * | |
33 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR | |
34 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES | |
35 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. | |
36 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, | |
37 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
38 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
39 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
40 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
41 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF | |
42 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
5260325f | 43 | */ |
8efc0c15 | 44 | |
45 | #include "includes.h" | |
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> | |
5b04a8bf | 52 | #include <sys/socket.h> |
aa2eae64 | 53 | #include <sys/wait.h> |
a75f5360 | 54 | |
028094f4 | 55 | #include <errno.h> |
d3221cca | 56 | #include <fcntl.h> |
c8dfff33 | 57 | #if defined(HAVE_NETDB_H) |
58 | # include <netdb.h> | |
59 | #endif | |
b5b88c19 | 60 | #ifdef HAVE_PATHS_H |
a75f5360 | 61 | #include <paths.h> |
b5b88c19 | 62 | #endif |
22bbb3e6 | 63 | #include <grp.h> |
b1842393 | 64 | #include <pwd.h> |
ada68823 | 65 | #include <signal.h> |
8efc0c15 | 66 | |
42f11eb2 | 67 | #include <openssl/dh.h> |
68 | #include <openssl/bn.h> | |
436c347c | 69 | #include <openssl/md5.h> |
1853d1ef | 70 | #include <openssl/rand.h> |
6e879cb4 | 71 | #ifdef HAVE_SECUREWARE |
72 | #include <sys/security.h> | |
73 | #include <prot.h> | |
74 | #endif | |
42f11eb2 | 75 | |
76 | #include "ssh.h" | |
77 | #include "ssh1.h" | |
78 | #include "ssh2.h" | |
8efc0c15 | 79 | #include "xmalloc.h" |
80 | #include "rsa.h" | |
1729c161 | 81 | #include "sshpty.h" |
8efc0c15 | 82 | #include "packet.h" |
42f11eb2 | 83 | #include "log.h" |
8efc0c15 | 84 | #include "servconf.h" |
85 | #include "uidswap.h" | |
86 | #include "compat.h" | |
7368a6c8 | 87 | #include "buffer.h" |
b9a549d7 | 88 | #include "bufaux.h" |
42f11eb2 | 89 | #include "cipher.h" |
e78a59f5 | 90 | #include "kex.h" |
7368a6c8 | 91 | #include "key.h" |
94ec8c6b | 92 | #include "dh.h" |
e78a59f5 | 93 | #include "myproposal.h" |
a306f2dd | 94 | #include "authfile.h" |
42f11eb2 | 95 | #include "pathnames.h" |
96 | #include "atomicio.h" | |
97 | #include "canohost.h" | |
98 | #include "auth.h" | |
99 | #include "misc.h" | |
b9a549d7 | 100 | #include "msg.h" |
a5c9ffdb | 101 | #include "dispatch.h" |
e4d7f734 | 102 | #include "channels.h" |
1b34c1b3 | 103 | #include "session.h" |
1853d1ef | 104 | #include "monitor_mm.h" |
105 | #include "monitor.h" | |
106 | #include "monitor_wrap.h" | |
107 | #include "monitor_fdpass.h" | |
28015df4 | 108 | #include "version.h" |
8efc0c15 | 109 | |
110 | #ifdef LIBWRAP | |
111 | #include <tcpd.h> | |
112 | #include <syslog.h> | |
113 | int allow_severity = LOG_INFO; | |
114 | int deny_severity = LOG_WARNING; | |
115 | #endif /* LIBWRAP */ | |
116 | ||
117 | #ifndef O_NOCTTY | |
118 | #define O_NOCTTY 0 | |
119 | #endif | |
120 | ||
b250e837 | 121 | /* Re-exec fds */ |
122 | #define REEXEC_DEVCRYPTO_RESERVED_FD (STDERR_FILENO + 1) | |
123 | #define REEXEC_STARTUP_PIPE_FD (STDERR_FILENO + 2) | |
124 | #define REEXEC_CONFIG_PASS_FD (STDERR_FILENO + 3) | |
125 | #define REEXEC_MIN_FREE_FD (STDERR_FILENO + 4) | |
126 | ||
260d427b | 127 | extern char *__progname; |
260d427b | 128 | |
8efc0c15 | 129 | /* Server configuration options. */ |
130 | ServerOptions options; | |
131 | ||
132 | /* Name of the server configuration file. */ | |
42f11eb2 | 133 | char *config_file_name = _PATH_SERVER_CONFIG_FILE; |
8efc0c15 | 134 | |
5260325f | 135 | /* |
136 | * Debug mode flag. This can be set on the command line. If debug | |
137 | * mode is enabled, extra debugging output will be sent to the system | |
138 | * log, the daemon will not go to background, and will exit after processing | |
139 | * the first connection. | |
140 | */ | |
8efc0c15 | 141 | int debug_flag = 0; |
142 | ||
f87f09aa | 143 | /* Flag indicating that the daemon should only test the configuration and keys. */ |
144 | int test_flag = 0; | |
145 | ||
8efc0c15 | 146 | /* Flag indicating that the daemon is being started from inetd. */ |
147 | int inetd_flag = 0; | |
148 | ||
0b6fbf03 | 149 | /* Flag indicating that sshd should not detach and become a daemon. */ |
150 | int no_daemon_flag = 0; | |
151 | ||
6a17f9c2 | 152 | /* debug goes to stderr unless inetd_flag is set */ |
153 | int log_stderr = 0; | |
154 | ||
8efc0c15 | 155 | /* Saved arguments to main(). */ |
156 | char **saved_argv; | |
4d33e531 | 157 | int saved_argc; |
8efc0c15 | 158 | |
b9a549d7 | 159 | /* re-exec */ |
160 | int rexeced_flag = 0; | |
161 | int rexec_flag = 1; | |
162 | int rexec_argc = 0; | |
163 | char **rexec_argv; | |
164 | ||
aa3378df | 165 | /* |
48e671d5 | 166 | * The sockets that the server is listening; this is used in the SIGHUP |
167 | * signal handler. | |
aa3378df | 168 | */ |
48e671d5 | 169 | #define MAX_LISTEN_SOCKS 16 |
170 | int listen_socks[MAX_LISTEN_SOCKS]; | |
171 | int num_listen_socks = 0; | |
8efc0c15 | 172 | |
aa3378df | 173 | /* |
174 | * the client's version string, passed by sshd2 in compat mode. if != NULL, | |
175 | * sshd will skip the version-number exchange | |
176 | */ | |
5260325f | 177 | char *client_version_string = NULL; |
7368a6c8 | 178 | char *server_version_string = NULL; |
8efc0c15 | 179 | |
7a37c112 | 180 | /* for rekeying XXX fixme */ |
181 | Kex *xxx_kex; | |
182 | ||
aa3378df | 183 | /* |
184 | * Any really sensitive data in the application is contained in this | |
185 | * structure. The idea is that this structure could be locked into memory so | |
186 | * that the pages do not get written into swap. However, there are some | |
187 | * problems. The private key contains BIGNUMs, and we do not (in principle) | |
188 | * have access to the internals of them, and locking just the structure is | |
189 | * not very useful. Currently, memory locking is not implemented. | |
190 | */ | |
5260325f | 191 | struct { |
cb7bd922 | 192 | Key *server_key; /* ephemeral server key */ |
fa08c86b | 193 | Key *ssh1_host_key; /* ssh1 host key */ |
194 | Key **host_keys; /* all private host keys */ | |
195 | int have_ssh1_key; | |
196 | int have_ssh2_key; | |
00be5382 | 197 | u_char ssh1_cookie[SSH_SESSION_KEY_LENGTH]; |
8efc0c15 | 198 | } sensitive_data; |
199 | ||
aa3378df | 200 | /* |
59c97189 | 201 | * Flag indicating whether the RSA server key needs to be regenerated. |
202 | * Is set in the SIGALRM handler and cleared when the key is regenerated. | |
aa3378df | 203 | */ |
7a934d1b | 204 | static volatile sig_atomic_t key_do_regen = 0; |
8efc0c15 | 205 | |
c9130033 | 206 | /* This is set to true when a signal is received. */ |
7a934d1b | 207 | static volatile sig_atomic_t received_sighup = 0; |
208 | static volatile sig_atomic_t received_sigterm = 0; | |
8efc0c15 | 209 | |
7368a6c8 | 210 | /* session identifier, used by RSA-auth */ |
1e3b8b07 | 211 | u_char session_id[16]; |
e7c0f9d5 | 212 | |
a306f2dd | 213 | /* same for ssh2 */ |
1e3b8b07 | 214 | u_char *session_id2 = NULL; |
a27002e5 | 215 | u_int session_id2_len = 0; |
a306f2dd | 216 | |
c345cf9d | 217 | /* record remote hostname or ip */ |
1e3b8b07 | 218 | u_int utmp_len = MAXHOSTNAMELEN; |
c345cf9d | 219 | |
7ace8c3b | 220 | /* options.max_startup sized array of fd ints */ |
221 | int *startup_pipes = NULL; | |
222 | int startup_pipe; /* in child */ | |
223 | ||
1853d1ef | 224 | /* variables used for privilege separation */ |
d231781a | 225 | int use_privsep = -1; |
a9b33b95 | 226 | struct monitor *pmonitor = NULL; |
1853d1ef | 227 | |
2362db19 | 228 | /* global authentication context */ |
229 | Authctxt *the_authctxt = NULL; | |
230 | ||
d231781a | 231 | /* sshd_config buffer */ |
232 | Buffer cfg; | |
233 | ||
be2ca0c9 | 234 | /* message to be displayed after login */ |
235 | Buffer loginmsg; | |
236 | ||
7368a6c8 | 237 | /* Prototypes for various functions defined later in this file. */ |
396c147e | 238 | void destroy_sensitive_data(void); |
1853d1ef | 239 | void demote_sensitive_data(void); |
c8d54615 | 240 | |
396c147e | 241 | static void do_ssh1_kex(void); |
242 | static void do_ssh2_kex(void); | |
94ec8c6b | 243 | |
48e671d5 | 244 | /* |
245 | * Close all listening sockets | |
246 | */ | |
396c147e | 247 | static void |
48e671d5 | 248 | close_listen_socks(void) |
249 | { | |
250 | int i; | |
e424e241 | 251 | |
48e671d5 | 252 | for (i = 0; i < num_listen_socks; i++) |
253 | close(listen_socks[i]); | |
254 | num_listen_socks = -1; | |
255 | } | |
256 | ||
7ace8c3b | 257 | static void |
258 | close_startup_pipes(void) | |
259 | { | |
260 | int i; | |
e424e241 | 261 | |
7ace8c3b | 262 | if (startup_pipes) |
263 | for (i = 0; i < options.max_startups; i++) | |
264 | if (startup_pipes[i] != -1) | |
265 | close(startup_pipes[i]); | |
266 | } | |
267 | ||
5260325f | 268 | /* |
269 | * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP; | |
270 | * the effect is to reread the configuration file (and to regenerate | |
271 | * the server key). | |
272 | */ | |
3efa8ea9 | 273 | |
274 | /*ARGSUSED*/ | |
396c147e | 275 | static void |
5260325f | 276 | sighup_handler(int sig) |
8efc0c15 | 277 | { |
6056eb35 | 278 | int save_errno = errno; |
279 | ||
5260325f | 280 | received_sighup = 1; |
281 | signal(SIGHUP, sighup_handler); | |
6056eb35 | 282 | errno = save_errno; |
8efc0c15 | 283 | } |
284 | ||
5260325f | 285 | /* |
286 | * Called from the main program after receiving SIGHUP. | |
287 | * Restarts the server. | |
288 | */ | |
396c147e | 289 | static void |
5ca51e19 | 290 | sighup_restart(void) |
8efc0c15 | 291 | { |
bbe88b6d | 292 | logit("Received SIGHUP; restarting."); |
48e671d5 | 293 | close_listen_socks(); |
7ace8c3b | 294 | close_startup_pipes(); |
5260325f | 295 | execv(saved_argv[0], saved_argv); |
bbe88b6d | 296 | logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0], |
e424e241 | 297 | strerror(errno)); |
5260325f | 298 | exit(1); |
8efc0c15 | 299 | } |
300 | ||
5260325f | 301 | /* |
302 | * Generic signal handler for terminating signals in the master daemon. | |
5260325f | 303 | */ |
3efa8ea9 | 304 | /*ARGSUSED*/ |
396c147e | 305 | static void |
5260325f | 306 | sigterm_handler(int sig) |
8efc0c15 | 307 | { |
c9130033 | 308 | received_sigterm = sig; |
8efc0c15 | 309 | } |
310 | ||
5260325f | 311 | /* |
312 | * SIGCHLD handler. This is called whenever a child dies. This will then | |
c9130033 | 313 | * reap any zombies left by exited children. |
5260325f | 314 | */ |
3efa8ea9 | 315 | /*ARGSUSED*/ |
396c147e | 316 | static void |
5260325f | 317 | main_sigchld_handler(int sig) |
8efc0c15 | 318 | { |
5260325f | 319 | int save_errno = errno; |
e424e241 | 320 | pid_t pid; |
5260325f | 321 | int status; |
5ad13cd7 | 322 | |
8c38e88b | 323 | while ((pid = waitpid(-1, &status, WNOHANG)) > 0 || |
324 | (pid < 0 && errno == EINTR)) | |
5260325f | 325 | ; |
5ad13cd7 | 326 | |
5260325f | 327 | signal(SIGCHLD, main_sigchld_handler); |
328 | errno = save_errno; | |
8efc0c15 | 329 | } |
330 | ||
5260325f | 331 | /* |
332 | * Signal handler for the alarm after the login grace period has expired. | |
333 | */ | |
3efa8ea9 | 334 | /*ARGSUSED*/ |
396c147e | 335 | static void |
5260325f | 336 | grace_alarm_handler(int sig) |
8efc0c15 | 337 | { |
c9130033 | 338 | /* XXX no idea how fix this signal handler */ |
339 | ||
a9b33b95 | 340 | if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0) |
341 | kill(pmonitor->m_pid, SIGALRM); | |
342 | ||
5260325f | 343 | /* Log error and exit. */ |
26b9a3d2 | 344 | fatal("Timeout before authentication for %s", get_remote_ipaddr()); |
5260325f | 345 | } |
8efc0c15 | 346 | |
5260325f | 347 | /* |
348 | * Signal handler for the key regeneration alarm. Note that this | |
349 | * alarm only occurs in the daemon waiting for connections, and it does not | |
350 | * do anything with the private key or random state before forking. | |
351 | * Thus there should be no concurrency control/asynchronous execution | |
352 | * problems. | |
353 | */ | |
396c147e | 354 | static void |
cb7bd922 | 355 | generate_ephemeral_server_key(void) |
fa08c86b | 356 | { |
7fdc56c5 | 357 | u_int32_t rnd = 0; |
00be5382 | 358 | int i; |
359 | ||
cd332296 | 360 | verbose("Generating %s%d bit RSA key.", |
76ca7b01 | 361 | sensitive_data.server_key ? "new " : "", options.server_key_bits); |
fa08c86b | 362 | if (sensitive_data.server_key != NULL) |
363 | key_free(sensitive_data.server_key); | |
cd332296 | 364 | sensitive_data.server_key = key_generate(KEY_RSA1, |
76ca7b01 | 365 | options.server_key_bits); |
366 | verbose("RSA key generation complete."); | |
00be5382 | 367 | |
368 | for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) { | |
369 | if (i % 4 == 0) | |
7fdc56c5 | 370 | rnd = arc4random(); |
371 | sensitive_data.ssh1_cookie[i] = rnd & 0xff; | |
372 | rnd >>= 8; | |
00be5382 | 373 | } |
374 | arc4random_stir(); | |
fa08c86b | 375 | } |
f546c780 | 376 | |
3efa8ea9 | 377 | /*ARGSUSED*/ |
396c147e | 378 | static void |
5260325f | 379 | key_regeneration_alarm(int sig) |
380 | { | |
381 | int save_errno = errno; | |
e424e241 | 382 | |
59c97189 | 383 | signal(SIGALRM, SIG_DFL); |
5260325f | 384 | errno = save_errno; |
59c97189 | 385 | key_do_regen = 1; |
5260325f | 386 | } |
8efc0c15 | 387 | |
396c147e | 388 | static void |
7368a6c8 | 389 | sshd_exchange_identification(int sock_in, int sock_out) |
390 | { | |
2ceb8101 | 391 | u_int i; |
392 | int mismatch; | |
7368a6c8 | 393 | int remote_major, remote_minor; |
a8be9f80 | 394 | int major, minor; |
7368a6c8 | 395 | char *s; |
396 | char buf[256]; /* Must not be larger than remote_version. */ | |
397 | char remote_version[256]; /* Must be at least as big as buf. */ | |
398 | ||
a8be9f80 | 399 | if ((options.protocol & SSH_PROTO_1) && |
400 | (options.protocol & SSH_PROTO_2)) { | |
401 | major = PROTOCOL_MAJOR_1; | |
402 | minor = 99; | |
403 | } else if (options.protocol & SSH_PROTO_2) { | |
404 | major = PROTOCOL_MAJOR_2; | |
405 | minor = PROTOCOL_MINOR_2; | |
406 | } else { | |
407 | major = PROTOCOL_MAJOR_1; | |
408 | minor = PROTOCOL_MINOR_1; | |
409 | } | |
410 | snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", major, minor, SSH_VERSION); | |
7368a6c8 | 411 | server_version_string = xstrdup(buf); |
412 | ||
7b390973 | 413 | /* Send our protocol version identification. */ |
414 | if (atomicio(vwrite, sock_out, server_version_string, | |
415 | strlen(server_version_string)) | |
416 | != strlen(server_version_string)) { | |
417 | logit("Could not write ident string to %s", get_remote_ipaddr()); | |
2362db19 | 418 | cleanup_exit(255); |
7b390973 | 419 | } |
420 | ||
421 | /* Read other sides version identification. */ | |
422 | memset(buf, 0, sizeof(buf)); | |
423 | for (i = 0; i < sizeof(buf) - 1; i++) { | |
424 | if (atomicio(read, sock_in, &buf[i], 1) != 1) { | |
425 | logit("Did not receive identification string from %s", | |
426 | get_remote_ipaddr()); | |
2362db19 | 427 | cleanup_exit(255); |
7368a6c8 | 428 | } |
7b390973 | 429 | if (buf[i] == '\r') { |
430 | buf[i] = 0; | |
431 | /* Kludge for F-Secure Macintosh < 1.0.2 */ | |
432 | if (i == 12 && | |
433 | strncmp(buf, "SSH-1.5-W1.0", 12) == 0) | |
7368a6c8 | 434 | break; |
7b390973 | 435 | continue; |
436 | } | |
437 | if (buf[i] == '\n') { | |
438 | buf[i] = 0; | |
439 | break; | |
7368a6c8 | 440 | } |
7368a6c8 | 441 | } |
7b390973 | 442 | buf[sizeof(buf) - 1] = 0; |
443 | client_version_string = xstrdup(buf); | |
7368a6c8 | 444 | |
445 | /* | |
446 | * Check that the versions match. In future this might accept | |
447 | * several versions and set appropriate flags to handle them. | |
448 | */ | |
449 | if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n", | |
450 | &remote_major, &remote_minor, remote_version) != 3) { | |
6ae2364d | 451 | s = "Protocol mismatch.\n"; |
dc54438a | 452 | (void) atomicio(vwrite, sock_out, s, strlen(s)); |
7368a6c8 | 453 | close(sock_in); |
454 | close(sock_out); | |
bbe88b6d | 455 | logit("Bad protocol version identification '%.100s' from %s", |
7368a6c8 | 456 | client_version_string, get_remote_ipaddr()); |
2362db19 | 457 | cleanup_exit(255); |
7368a6c8 | 458 | } |
459 | debug("Client protocol version %d.%d; client software version %.100s", | |
184eed6a | 460 | remote_major, remote_minor, remote_version); |
7368a6c8 | 461 | |
e78a59f5 | 462 | compat_datafellows(remote_version); |
463 | ||
9a87e2ac | 464 | if (datafellows & SSH_BUG_PROBE) { |
bbe88b6d | 465 | logit("probed from %s with %s. Don't panic.", |
9a87e2ac | 466 | get_remote_ipaddr(), client_version_string); |
2362db19 | 467 | cleanup_exit(255); |
9a87e2ac | 468 | } |
469 | ||
3a1c54d4 | 470 | if (datafellows & SSH_BUG_SCANNER) { |
bbe88b6d | 471 | logit("scanned from %s with %s. Don't panic.", |
3a1c54d4 | 472 | get_remote_ipaddr(), client_version_string); |
2362db19 | 473 | cleanup_exit(255); |
3a1c54d4 | 474 | } |
475 | ||
a8be9f80 | 476 | mismatch = 0; |
6aacefa7 | 477 | switch (remote_major) { |
7368a6c8 | 478 | case 1: |
a306f2dd | 479 | if (remote_minor == 99) { |
480 | if (options.protocol & SSH_PROTO_2) | |
481 | enable_compat20(); | |
482 | else | |
483 | mismatch = 1; | |
484 | break; | |
485 | } | |
a8be9f80 | 486 | if (!(options.protocol & SSH_PROTO_1)) { |
487 | mismatch = 1; | |
488 | break; | |
489 | } | |
7368a6c8 | 490 | if (remote_minor < 3) { |
089fbbd2 | 491 | packet_disconnect("Your ssh version is too old and " |
7368a6c8 | 492 | "is no longer supported. Please install a newer version."); |
493 | } else if (remote_minor == 3) { | |
494 | /* note that this disables agent-forwarding */ | |
495 | enable_compat13(); | |
496 | } | |
a8be9f80 | 497 | break; |
e78a59f5 | 498 | case 2: |
a8be9f80 | 499 | if (options.protocol & SSH_PROTO_2) { |
e78a59f5 | 500 | enable_compat20(); |
501 | break; | |
502 | } | |
503 | /* FALLTHROUGH */ | |
6ae2364d | 504 | default: |
a8be9f80 | 505 | mismatch = 1; |
506 | break; | |
507 | } | |
508 | chop(server_version_string); | |
a8be9f80 | 509 | debug("Local version string %.200s", server_version_string); |
510 | ||
511 | if (mismatch) { | |
7368a6c8 | 512 | s = "Protocol major versions differ.\n"; |
dc54438a | 513 | (void) atomicio(vwrite, sock_out, s, strlen(s)); |
7368a6c8 | 514 | close(sock_in); |
515 | close(sock_out); | |
bbe88b6d | 516 | logit("Protocol major versions differ for %s: %.200s vs. %.200s", |
a8be9f80 | 517 | get_remote_ipaddr(), |
518 | server_version_string, client_version_string); | |
2362db19 | 519 | cleanup_exit(255); |
7368a6c8 | 520 | } |
a306f2dd | 521 | } |
522 | ||
fa08c86b | 523 | /* Destroy the host and server keys. They will no longer be needed. */ |
a306f2dd | 524 | void |
525 | destroy_sensitive_data(void) | |
526 | { | |
fa08c86b | 527 | int i; |
528 | ||
529 | if (sensitive_data.server_key) { | |
530 | key_free(sensitive_data.server_key); | |
531 | sensitive_data.server_key = NULL; | |
532 | } | |
184eed6a | 533 | for (i = 0; i < options.num_host_key_files; i++) { |
fa08c86b | 534 | if (sensitive_data.host_keys[i]) { |
535 | key_free(sensitive_data.host_keys[i]); | |
536 | sensitive_data.host_keys[i] = NULL; | |
537 | } | |
538 | } | |
539 | sensitive_data.ssh1_host_key = NULL; | |
00be5382 | 540 | memset(sensitive_data.ssh1_cookie, 0, SSH_SESSION_KEY_LENGTH); |
fa08c86b | 541 | } |
fa08c86b | 542 | |
1853d1ef | 543 | /* Demote private to public keys for network child */ |
544 | void | |
545 | demote_sensitive_data(void) | |
546 | { | |
547 | Key *tmp; | |
548 | int i; | |
549 | ||
550 | if (sensitive_data.server_key) { | |
551 | tmp = key_demote(sensitive_data.server_key); | |
552 | key_free(sensitive_data.server_key); | |
553 | sensitive_data.server_key = tmp; | |
554 | } | |
555 | ||
556 | for (i = 0; i < options.num_host_key_files; i++) { | |
557 | if (sensitive_data.host_keys[i]) { | |
558 | tmp = key_demote(sensitive_data.host_keys[i]); | |
559 | key_free(sensitive_data.host_keys[i]); | |
560 | sensitive_data.host_keys[i] = tmp; | |
561 | if (tmp->type == KEY_RSA1) | |
562 | sensitive_data.ssh1_host_key = tmp; | |
563 | } | |
564 | } | |
565 | ||
566 | /* We do not clear ssh1_host key and cookie. XXX - Okay Niels? */ | |
567 | } | |
568 | ||
51aeb639 | 569 | static void |
1853d1ef | 570 | privsep_preauth_child(void) |
571 | { | |
7fdc56c5 | 572 | u_int32_t rnd[256]; |
6ded293b | 573 | gid_t gidset[1]; |
2ea6de2b | 574 | struct passwd *pw; |
e424e241 | 575 | int i; |
1853d1ef | 576 | |
577 | /* Enable challenge-response authentication for privilege separation */ | |
578 | privsep_challenge_enable(); | |
579 | ||
580 | for (i = 0; i < 256; i++) | |
7fdc56c5 | 581 | rnd[i] = arc4random(); |
582 | RAND_seed(rnd, sizeof(rnd)); | |
1853d1ef | 583 | |
584 | /* Demote the private keys to public keys. */ | |
585 | demote_sensitive_data(); | |
586 | ||
2ea6de2b | 587 | if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) |
cdc4fc39 | 588 | fatal("Privilege separation user %s does not exist", |
589 | SSH_PRIVSEP_USER); | |
2ea6de2b | 590 | memset(pw->pw_passwd, 0, strlen(pw->pw_passwd)); |
591 | endpwent(); | |
592 | ||
343288b8 | 593 | /* Change our root directory */ |
1c352e97 | 594 | if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1) |
595 | fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR, | |
596 | strerror(errno)); | |
1853d1ef | 597 | if (chdir("/") == -1) |
edfb66cb | 598 | fatal("chdir(\"/\"): %s", strerror(errno)); |
762715ce | 599 | |
1853d1ef | 600 | /* Drop our privileges */ |
2ea6de2b | 601 | debug3("privsep user:group %u:%u", (u_int)pw->pw_uid, |
602 | (u_int)pw->pw_gid); | |
87809a1f | 603 | #if 0 |
6ff58a4b | 604 | /* XXX not ready, too heavy after chroot */ |
2ea6de2b | 605 | do_setusercontext(pw); |
87809a1f | 606 | #else |
607 | gidset[0] = pw->pw_gid; | |
87809a1f | 608 | if (setgroups(1, gidset) < 0) |
609 | fatal("setgroups: %.100s", strerror(errno)); | |
610 | permanently_set_uid(pw); | |
611 | #endif | |
1853d1ef | 612 | } |
613 | ||
2362db19 | 614 | static int |
615 | privsep_preauth(Authctxt *authctxt) | |
1853d1ef | 616 | { |
1853d1ef | 617 | int status; |
324bf712 | 618 | pid_t pid; |
1853d1ef | 619 | |
324bf712 | 620 | /* Set up unprivileged child process to deal with network data */ |
b5a28cbc | 621 | pmonitor = monitor_init(); |
324bf712 | 622 | /* Store a pointer to the kex for later rekeying */ |
b5a28cbc | 623 | pmonitor->m_pkex = &xxx_kex; |
324bf712 | 624 | |
625 | pid = fork(); | |
626 | if (pid == -1) { | |
627 | fatal("fork of unprivileged child failed"); | |
628 | } else if (pid != 0) { | |
c457707e | 629 | debug2("Network child is on pid %ld", (long)pid); |
324bf712 | 630 | |
b5a28cbc | 631 | close(pmonitor->m_recvfd); |
a9b33b95 | 632 | pmonitor->m_pid = pid; |
2362db19 | 633 | monitor_child_preauth(authctxt, pmonitor); |
b5a28cbc | 634 | close(pmonitor->m_sendfd); |
324bf712 | 635 | |
636 | /* Sync memory */ | |
b5a28cbc | 637 | monitor_sync(pmonitor); |
324bf712 | 638 | |
639 | /* Wait for the child's exit status */ | |
8c38e88b | 640 | while (waitpid(pid, &status, 0) < 0) |
641 | if (errno != EINTR) | |
642 | break; | |
2362db19 | 643 | return (1); |
324bf712 | 644 | } else { |
645 | /* child */ | |
646 | ||
b5a28cbc | 647 | close(pmonitor->m_sendfd); |
324bf712 | 648 | |
649 | /* Demote the child */ | |
650 | if (getuid() == 0 || geteuid() == 0) | |
651 | privsep_preauth_child(); | |
47c36e5b | 652 | setproctitle("%s", "[net]"); |
324bf712 | 653 | } |
2362db19 | 654 | return (0); |
324bf712 | 655 | } |
656 | ||
657 | static void | |
658 | privsep_postauth(Authctxt *authctxt) | |
659 | { | |
94d8258b | 660 | #ifdef DISABLE_FD_PASSING |
d170feb1 | 661 | if (1) { |
662 | #else | |
1853d1ef | 663 | if (authctxt->pw->pw_uid == 0 || options.use_login) { |
d170feb1 | 664 | #endif |
1853d1ef | 665 | /* File descriptor passing is broken or root login */ |
1853d1ef | 666 | use_privsep = 0; |
ae25711b | 667 | goto skip; |
1853d1ef | 668 | } |
762715ce | 669 | |
1853d1ef | 670 | /* New socket pair */ |
b5a28cbc | 671 | monitor_reinit(pmonitor); |
1853d1ef | 672 | |
b5a28cbc | 673 | pmonitor->m_pid = fork(); |
674 | if (pmonitor->m_pid == -1) | |
1853d1ef | 675 | fatal("fork of unprivileged child failed"); |
b5a28cbc | 676 | else if (pmonitor->m_pid != 0) { |
c457707e | 677 | debug2("User child is on pid %ld", (long)pmonitor->m_pid); |
b5a28cbc | 678 | close(pmonitor->m_recvfd); |
f143ed33 | 679 | buffer_clear(&loginmsg); |
b5a28cbc | 680 | monitor_child_postauth(pmonitor); |
1853d1ef | 681 | |
682 | /* NEVERREACHED */ | |
683 | exit(0); | |
684 | } | |
685 | ||
b5a28cbc | 686 | close(pmonitor->m_sendfd); |
1853d1ef | 687 | |
688 | /* Demote the private keys to public keys. */ | |
689 | demote_sensitive_data(); | |
690 | ||
691 | /* Drop privileges */ | |
692 | do_setusercontext(authctxt->pw); | |
693 | ||
ae25711b | 694 | skip: |
1853d1ef | 695 | /* It is safe now to apply the key state */ |
b5a28cbc | 696 | monitor_apply_keystate(pmonitor); |
07200973 | 697 | |
698 | /* | |
699 | * Tell the packet layer that authentication was successful, since | |
700 | * this information is not part of the key state. | |
701 | */ | |
702 | packet_set_authenticated(); | |
1853d1ef | 703 | } |
704 | ||
396c147e | 705 | static char * |
fa08c86b | 706 | list_hostkey_types(void) |
707 | { | |
3469eac4 | 708 | Buffer b; |
b6c7b7b7 | 709 | const char *p; |
710 | char *ret; | |
fa08c86b | 711 | int i; |
3469eac4 | 712 | |
713 | buffer_init(&b); | |
184eed6a | 714 | for (i = 0; i < options.num_host_key_files; i++) { |
fa08c86b | 715 | Key *key = sensitive_data.host_keys[i]; |
716 | if (key == NULL) | |
717 | continue; | |
6aacefa7 | 718 | switch (key->type) { |
fa08c86b | 719 | case KEY_RSA: |
720 | case KEY_DSA: | |
3469eac4 | 721 | if (buffer_len(&b) > 0) |
722 | buffer_append(&b, ",", 1); | |
723 | p = key_ssh_name(key); | |
724 | buffer_append(&b, p, strlen(p)); | |
fa08c86b | 725 | break; |
726 | } | |
727 | } | |
3469eac4 | 728 | buffer_append(&b, "\0", 1); |
b6c7b7b7 | 729 | ret = xstrdup(buffer_ptr(&b)); |
3469eac4 | 730 | buffer_free(&b); |
b6c7b7b7 | 731 | debug("list_hostkey_types: %s", ret); |
732 | return ret; | |
fa08c86b | 733 | } |
734 | ||
1853d1ef | 735 | Key * |
fa08c86b | 736 | get_hostkey_by_type(int type) |
737 | { | |
738 | int i; | |
e424e241 | 739 | |
184eed6a | 740 | for (i = 0; i < options.num_host_key_files; i++) { |
fa08c86b | 741 | Key *key = sensitive_data.host_keys[i]; |
742 | if (key != NULL && key->type == type) | |
743 | return key; | |
744 | } | |
745 | return NULL; | |
7368a6c8 | 746 | } |
747 | ||
1853d1ef | 748 | Key * |
749 | get_hostkey_by_index(int ind) | |
750 | { | |
751 | if (ind < 0 || ind >= options.num_host_key_files) | |
752 | return (NULL); | |
753 | return (sensitive_data.host_keys[ind]); | |
754 | } | |
755 | ||
756 | int | |
757 | get_hostkey_index(Key *key) | |
758 | { | |
759 | int i; | |
e424e241 | 760 | |
1853d1ef | 761 | for (i = 0; i < options.num_host_key_files; i++) { |
762 | if (key == sensitive_data.host_keys[i]) | |
763 | return (i); | |
764 | } | |
765 | return (-1); | |
766 | } | |
767 | ||
c345cf9d | 768 | /* |
769 | * returns 1 if connection should be dropped, 0 otherwise. | |
770 | * dropping starts at connection #max_startups_begin with a probability | |
771 | * of (max_startups_rate/100). the probability increases linearly until | |
772 | * all connections are dropped for startups > max_startups | |
773 | */ | |
396c147e | 774 | static int |
c345cf9d | 775 | drop_connection(int startups) |
776 | { | |
1c5eab6f | 777 | int p, r; |
c345cf9d | 778 | |
779 | if (startups < options.max_startups_begin) | |
780 | return 0; | |
781 | if (startups >= options.max_startups) | |
782 | return 1; | |
783 | if (options.max_startups_rate == 100) | |
784 | return 1; | |
785 | ||
786 | p = 100 - options.max_startups_rate; | |
787 | p *= startups - options.max_startups_begin; | |
1c5eab6f | 788 | p /= options.max_startups - options.max_startups_begin; |
c345cf9d | 789 | p += options.max_startups_rate; |
1c5eab6f | 790 | r = arc4random() % 100; |
c345cf9d | 791 | |
e9aec1d4 | 792 | debug("drop_connection: p %d, r %d", p, r); |
c345cf9d | 793 | return (r < p) ? 1 : 0; |
794 | } | |
795 | ||
2717fa0f | 796 | static void |
797 | usage(void) | |
798 | { | |
85ac7a84 | 799 | fprintf(stderr, "%s, %s\n", |
4526e8c2 | 800 | SSH_RELEASE, SSLeay_version(SSLEAY_VERSION)); |
65edde94 | 801 | fprintf(stderr, |
802 | "usage: sshd [-46Ddeiqt] [-b bits] [-f config_file] [-g login_grace_time]\n" | |
803 | " [-h host_key_file] [-k key_gen_time] [-o option] [-p port] [-u len]\n" | |
804 | ); | |
2717fa0f | 805 | exit(1); |
806 | } | |
807 | ||
b9a549d7 | 808 | static void |
809 | send_rexec_state(int fd, Buffer *conf) | |
810 | { | |
811 | Buffer m; | |
812 | ||
813 | debug3("%s: entering fd = %d config len %d", __func__, fd, | |
814 | buffer_len(conf)); | |
815 | ||
816 | /* | |
817 | * Protocol from reexec master to child: | |
818 | * string configuration | |
819 | * u_int ephemeral_key_follows | |
820 | * bignum e (only if ephemeral_key_follows == 1) | |
821 | * bignum n " | |
822 | * bignum d " | |
823 | * bignum iqmp " | |
824 | * bignum p " | |
825 | * bignum q " | |
72f02ae7 | 826 | * string rngseed (only if OpenSSL is not self-seeded) |
b9a549d7 | 827 | */ |
828 | buffer_init(&m); | |
829 | buffer_put_cstring(&m, buffer_ptr(conf)); | |
830 | ||
f2107e97 | 831 | if (sensitive_data.server_key != NULL && |
b9a549d7 | 832 | sensitive_data.server_key->type == KEY_RSA1) { |
833 | buffer_put_int(&m, 1); | |
834 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->e); | |
835 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->n); | |
836 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->d); | |
837 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->iqmp); | |
838 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->p); | |
839 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->q); | |
840 | } else | |
841 | buffer_put_int(&m, 0); | |
842 | ||
72f02ae7 | 843 | #ifndef OPENSSL_PRNG_ONLY |
844 | rexec_send_rng_seed(&m); | |
845 | #endif | |
846 | ||
b9a549d7 | 847 | if (ssh_msg_send(fd, 0, &m) == -1) |
848 | fatal("%s: ssh_msg_send failed", __func__); | |
849 | ||
850 | buffer_free(&m); | |
851 | ||
852 | debug3("%s: done", __func__); | |
853 | } | |
854 | ||
855 | static void | |
856 | recv_rexec_state(int fd, Buffer *conf) | |
857 | { | |
858 | Buffer m; | |
859 | char *cp; | |
860 | u_int len; | |
861 | ||
862 | debug3("%s: entering fd = %d", __func__, fd); | |
863 | ||
864 | buffer_init(&m); | |
865 | ||
866 | if (ssh_msg_recv(fd, &m) == -1) | |
867 | fatal("%s: ssh_msg_recv failed", __func__); | |
868 | if (buffer_get_char(&m) != 0) | |
869 | fatal("%s: rexec version mismatch", __func__); | |
870 | ||
871 | cp = buffer_get_string(&m, &len); | |
872 | if (conf != NULL) | |
873 | buffer_append(conf, cp, len + 1); | |
874 | xfree(cp); | |
875 | ||
876 | if (buffer_get_int(&m)) { | |
877 | if (sensitive_data.server_key != NULL) | |
878 | key_free(sensitive_data.server_key); | |
879 | sensitive_data.server_key = key_new_private(KEY_RSA1); | |
880 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->e); | |
881 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->n); | |
882 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->d); | |
883 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->iqmp); | |
884 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->p); | |
885 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->q); | |
886 | rsa_generate_additional_parameters( | |
887 | sensitive_data.server_key->rsa); | |
888 | } | |
72f02ae7 | 889 | |
890 | #ifndef OPENSSL_PRNG_ONLY | |
891 | rexec_recv_rng_seed(&m); | |
892 | #endif | |
893 | ||
b9a549d7 | 894 | buffer_free(&m); |
895 | ||
896 | debug3("%s: done", __func__); | |
897 | } | |
898 | ||
5260325f | 899 | /* |
900 | * Main program for the daemon. | |
901 | */ | |
8efc0c15 | 902 | int |
903 | main(int ac, char **av) | |
904 | { | |
5260325f | 905 | extern char *optarg; |
906 | extern int optind; | |
52e3daed | 907 | int opt, j, i, on = 1; |
83529a6b | 908 | int sock_in = -1, sock_out = -1, newsock = -1; |
9da5c3c9 | 909 | pid_t pid; |
48e671d5 | 910 | socklen_t fromlen; |
48e671d5 | 911 | fd_set *fdset; |
912 | struct sockaddr_storage from; | |
5260325f | 913 | const char *remote_ip; |
914 | int remote_port; | |
5260325f | 915 | FILE *f; |
48e671d5 | 916 | struct addrinfo *ai; |
917 | char ntop[NI_MAXHOST], strport[NI_MAXSERV]; | |
c5894280 | 918 | char *line; |
48e671d5 | 919 | int listen_sock, maxfd; |
9216f89c | 920 | int startup_p[2] = { -1 , -1 }, config_s[2] = { -1 , -1 }; |
089fbbd2 | 921 | int startups = 0; |
aeaa3d9e | 922 | Key *key; |
2362db19 | 923 | Authctxt *authctxt; |
59c97189 | 924 | int ret, key_used = 0; |
5260325f | 925 | |
6e879cb4 | 926 | #ifdef HAVE_SECUREWARE |
927 | (void)set_auth_parameters(ac, av); | |
928 | #endif | |
fda04d7d | 929 | __progname = ssh_get_progname(av[0]); |
264dce47 | 930 | init_rng(); |
931 | ||
d0104542 | 932 | /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */ |
4d33e531 | 933 | saved_argc = ac; |
7706b4c7 | 934 | rexec_argc = ac; |
01d35895 | 935 | saved_argv = xcalloc(ac + 1, sizeof(*saved_argv)); |
d0104542 | 936 | for (i = 0; i < ac; i++) |
937 | saved_argv[i] = xstrdup(av[i]); | |
f420d2ba | 938 | saved_argv[i] = NULL; |
d0104542 | 939 | |
940 | #ifndef HAVE_SETPROCTITLE | |
941 | /* Prepare for later setproctitle emulation */ | |
942 | compat_init_setproctitle(ac, av); | |
416c732d | 943 | av = saved_argv; |
d0104542 | 944 | #endif |
5260325f | 945 | |
a4c0faa2 | 946 | if (geteuid() == 0 && setgroups(0, NULL) == -1) |
947 | debug("setgroups(): %.200s", strerror(errno)); | |
948 | ||
fd6168c1 | 949 | /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ |
950 | sanitise_stdfd(); | |
951 | ||
5260325f | 952 | /* Initialize configuration options to their default values. */ |
953 | initialize_server_options(&options); | |
954 | ||
955 | /* Parse command-line arguments. */ | |
b9a549d7 | 956 | while ((opt = getopt(ac, av, "f:p:b:k:h:g:u:o:dDeiqrtQR46")) != -1) { |
5260325f | 957 | switch (opt) { |
48e671d5 | 958 | case '4': |
31b41ceb | 959 | options.address_family = AF_INET; |
48e671d5 | 960 | break; |
961 | case '6': | |
31b41ceb | 962 | options.address_family = AF_INET6; |
48e671d5 | 963 | break; |
5260325f | 964 | case 'f': |
965 | config_file_name = optarg; | |
966 | break; | |
967 | case 'd': | |
e053cd2c | 968 | if (debug_flag == 0) { |
bcbf86ec | 969 | debug_flag = 1; |
970 | options.log_level = SYSLOG_LEVEL_DEBUG1; | |
e053cd2c | 971 | } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) |
bcbf86ec | 972 | options.log_level++; |
5260325f | 973 | break; |
0b6fbf03 | 974 | case 'D': |
975 | no_daemon_flag = 1; | |
976 | break; | |
ff14faf1 | 977 | case 'e': |
978 | log_stderr = 1; | |
979 | break; | |
5260325f | 980 | case 'i': |
981 | inetd_flag = 1; | |
982 | break; | |
b9a549d7 | 983 | case 'r': |
984 | rexec_flag = 0; | |
985 | break; | |
986 | case 'R': | |
987 | rexeced_flag = 1; | |
988 | inetd_flag = 1; | |
989 | break; | |
5260325f | 990 | case 'Q': |
9bd5b720 | 991 | /* ignored */ |
5260325f | 992 | break; |
993 | case 'q': | |
994 | options.log_level = SYSLOG_LEVEL_QUIET; | |
995 | break; | |
996 | case 'b': | |
3efa8ea9 | 997 | options.server_key_bits = (int)strtonum(optarg, 256, |
998 | 32768, NULL); | |
5260325f | 999 | break; |
1000 | case 'p': | |
48e671d5 | 1001 | options.ports_from_cmdline = 1; |
bcbf86ec | 1002 | if (options.num_ports >= MAX_PORTS) { |
1003 | fprintf(stderr, "too many ports.\n"); | |
1004 | exit(1); | |
1005 | } | |
2d2a2c65 | 1006 | options.ports[options.num_ports++] = a2port(optarg); |
1007 | if (options.ports[options.num_ports-1] == 0) { | |
1008 | fprintf(stderr, "Bad port number.\n"); | |
1009 | exit(1); | |
1010 | } | |
5260325f | 1011 | break; |
1012 | case 'g': | |
e2b1fb42 | 1013 | if ((options.login_grace_time = convtime(optarg)) == -1) { |
1014 | fprintf(stderr, "Invalid login grace time.\n"); | |
1015 | exit(1); | |
1016 | } | |
5260325f | 1017 | break; |
1018 | case 'k': | |
e2b1fb42 | 1019 | if ((options.key_regeneration_time = convtime(optarg)) == -1) { |
1020 | fprintf(stderr, "Invalid key regeneration interval.\n"); | |
1021 | exit(1); | |
1022 | } | |
5260325f | 1023 | break; |
1024 | case 'h': | |
fa08c86b | 1025 | if (options.num_host_key_files >= MAX_HOSTKEYS) { |
1026 | fprintf(stderr, "too many host keys.\n"); | |
1027 | exit(1); | |
1028 | } | |
1029 | options.host_key_files[options.num_host_key_files++] = optarg; | |
5260325f | 1030 | break; |
f87f09aa | 1031 | case 't': |
1032 | test_flag = 1; | |
1033 | break; | |
c345cf9d | 1034 | case 'u': |
3efa8ea9 | 1035 | utmp_len = (u_int)strtonum(optarg, 0, MAXHOSTNAMELEN+1, NULL); |
67f04db1 | 1036 | if (utmp_len > MAXHOSTNAMELEN) { |
1037 | fprintf(stderr, "Invalid utmp length.\n"); | |
1038 | exit(1); | |
1039 | } | |
c345cf9d | 1040 | break; |
2717fa0f | 1041 | case 'o': |
c5894280 | 1042 | line = xstrdup(optarg); |
1043 | if (process_server_config_line(&options, line, | |
d231781a | 1044 | "command-line", 0, NULL, NULL, NULL, NULL) != 0) |
184eed6a | 1045 | exit(1); |
c5894280 | 1046 | xfree(line); |
2717fa0f | 1047 | break; |
5260325f | 1048 | case '?': |
1049 | default: | |
2717fa0f | 1050 | usage(); |
1051 | break; | |
5260325f | 1052 | } |
1053 | } | |
b9a549d7 | 1054 | if (rexeced_flag || inetd_flag) |
1055 | rexec_flag = 0; | |
1056 | if (rexec_flag && (av[0] == NULL || *av[0] != '/')) | |
1057 | fatal("sshd re-exec requires execution with an absolute path"); | |
1058 | if (rexeced_flag) | |
b250e837 | 1059 | closefrom(REEXEC_MIN_FREE_FD); |
1060 | else | |
1061 | closefrom(REEXEC_DEVCRYPTO_RESERVED_FD); | |
b9a549d7 | 1062 | |
1a92bd7e | 1063 | SSLeay_add_all_algorithms(); |
5260325f | 1064 | |
48e671d5 | 1065 | /* |
1066 | * Force logging to stderr until we have loaded the private host | |
1067 | * key (unless started from inetd) | |
1068 | */ | |
1fe6a48f | 1069 | log_init(__progname, |
980c9344 | 1070 | options.log_level == SYSLOG_LEVEL_NOT_SET ? |
1071 | SYSLOG_LEVEL_INFO : options.log_level, | |
1072 | options.log_facility == SYSLOG_FACILITY_NOT_SET ? | |
1073 | SYSLOG_FACILITY_AUTH : options.log_facility, | |
51efad8c | 1074 | log_stderr || !inetd_flag); |
48e671d5 | 1075 | |
351f44a0 | 1076 | /* |
1077 | * Unset KRB5CCNAME, otherwise the user's session may inherit it from | |
1078 | * root's environment | |
d1cf9a87 | 1079 | */ |
3bfd27d5 | 1080 | if (getenv("KRB5CCNAME") != NULL) |
1081 | unsetenv("KRB5CCNAME"); | |
1082 | ||
ef51930f | 1083 | #ifdef _UNICOS |
e5ba4718 | 1084 | /* Cray can define user privs drop all privs now! |
1a23ac2c | 1085 | * Not needed on PRIV_SU systems! |
1086 | */ | |
1087 | drop_cray_privs(); | |
1088 | #endif | |
1089 | ||
b9a549d7 | 1090 | sensitive_data.server_key = NULL; |
1091 | sensitive_data.ssh1_host_key = NULL; | |
1092 | sensitive_data.have_ssh1_key = 0; | |
1093 | sensitive_data.have_ssh2_key = 0; | |
1094 | ||
1095 | /* Fetch our configuration */ | |
1096 | buffer_init(&cfg); | |
1097 | if (rexeced_flag) | |
b250e837 | 1098 | recv_rexec_state(REEXEC_CONFIG_PASS_FD, &cfg); |
b9a549d7 | 1099 | else |
1100 | load_server_config(config_file_name, &cfg); | |
1101 | ||
d231781a | 1102 | parse_server_config(&options, rexeced_flag ? "rexec" : config_file_name, |
1103 | &cfg, NULL, NULL, NULL); | |
5260325f | 1104 | |
72f02ae7 | 1105 | seed_rng(); |
1106 | ||
5260325f | 1107 | /* Fill in default values for those options not explicitly set. */ |
1108 | fill_default_server_options(&options); | |
1109 | ||
31b41ceb | 1110 | /* set default channel AF */ |
1111 | channel_set_af(options.address_family); | |
1112 | ||
5260325f | 1113 | /* Check that there are no remaining arguments. */ |
1114 | if (optind < ac) { | |
1115 | fprintf(stderr, "Extra argument %s.\n", av[optind]); | |
1116 | exit(1); | |
8efc0c15 | 1117 | } |
5260325f | 1118 | |
4526e8c2 | 1119 | debug("sshd version %.100s", SSH_RELEASE); |
5260325f | 1120 | |
fa08c86b | 1121 | /* load private host keys */ |
52e3daed | 1122 | sensitive_data.host_keys = xcalloc(options.num_host_key_files, |
343288b8 | 1123 | sizeof(Key *)); |
184eed6a | 1124 | for (i = 0; i < options.num_host_key_files; i++) |
1e3b8b07 | 1125 | sensitive_data.host_keys[i] = NULL; |
a306f2dd | 1126 | |
184eed6a | 1127 | for (i = 0; i < options.num_host_key_files; i++) { |
aeaa3d9e | 1128 | key = key_load_private(options.host_key_files[i], "", NULL); |
1129 | sensitive_data.host_keys[i] = key; | |
fa08c86b | 1130 | if (key == NULL) { |
58cfa257 | 1131 | error("Could not load host key: %s", |
1132 | options.host_key_files[i]); | |
aeaa3d9e | 1133 | sensitive_data.host_keys[i] = NULL; |
fa08c86b | 1134 | continue; |
a306f2dd | 1135 | } |
6aacefa7 | 1136 | switch (key->type) { |
fa08c86b | 1137 | case KEY_RSA1: |
1138 | sensitive_data.ssh1_host_key = key; | |
1139 | sensitive_data.have_ssh1_key = 1; | |
1140 | break; | |
1141 | case KEY_RSA: | |
1142 | case KEY_DSA: | |
1143 | sensitive_data.have_ssh2_key = 1; | |
1144 | break; | |
a306f2dd | 1145 | } |
aeaa3d9e | 1146 | debug("private host key: #%d type %d %s", i, key->type, |
1147 | key_type(key)); | |
fa08c86b | 1148 | } |
1149 | if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) { | |
bbe88b6d | 1150 | logit("Disabling protocol version 1. Could not load host key"); |
fa08c86b | 1151 | options.protocol &= ~SSH_PROTO_1; |
1152 | } | |
1153 | if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) { | |
bbe88b6d | 1154 | logit("Disabling protocol version 2. Could not load host key"); |
fa08c86b | 1155 | options.protocol &= ~SSH_PROTO_2; |
a306f2dd | 1156 | } |
6a416424 | 1157 | if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) { |
bbe88b6d | 1158 | logit("sshd: no hostkeys available -- exiting."); |
5260325f | 1159 | exit(1); |
1160 | } | |
5260325f | 1161 | |
a306f2dd | 1162 | /* Check certain values for sanity. */ |
1163 | if (options.protocol & SSH_PROTO_1) { | |
1164 | if (options.server_key_bits < 512 || | |
1165 | options.server_key_bits > 32768) { | |
1166 | fprintf(stderr, "Bad server key size.\n"); | |
1167 | exit(1); | |
1168 | } | |
1169 | /* | |
1170 | * Check that server and host key lengths differ sufficiently. This | |
1171 | * is necessary to make double encryption work with rsaref. Oh, I | |
1172 | * hate software patents. I dont know if this can go? Niels | |
1173 | */ | |
1174 | if (options.server_key_bits > | |
e424e241 | 1175 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) - |
1176 | SSH_KEY_BITS_RESERVED && options.server_key_bits < | |
1177 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + | |
1178 | SSH_KEY_BITS_RESERVED) { | |
a306f2dd | 1179 | options.server_key_bits = |
e424e241 | 1180 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + |
1181 | SSH_KEY_BITS_RESERVED; | |
a306f2dd | 1182 | debug("Forcing server key to %d bits to make it differ from host key.", |
1183 | options.server_key_bits); | |
1184 | } | |
1185 | } | |
1186 | ||
3cc54fbb | 1187 | if (use_privsep) { |
3cc54fbb | 1188 | struct stat st; |
1189 | ||
3efa8ea9 | 1190 | if (getpwnam(SSH_PRIVSEP_USER) == NULL) |
3cc54fbb | 1191 | fatal("Privilege separation user %s does not exist", |
1192 | SSH_PRIVSEP_USER); | |
1193 | if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) || | |
1194 | (S_ISDIR(st.st_mode) == 0)) | |
1195 | fatal("Missing privilege separation directory: %s", | |
1196 | _PATH_PRIVSEP_CHROOT_DIR); | |
b9b82dab | 1197 | |
1198 | #ifdef HAVE_CYGWIN | |
1199 | if (check_ntsec(_PATH_PRIVSEP_CHROOT_DIR) && | |
1200 | (st.st_uid != getuid () || | |
1201 | (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)) | |
1202 | #else | |
a56313d7 | 1203 | if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0) |
b9b82dab | 1204 | #endif |
5f021474 | 1205 | fatal("%s must be owned by root and not group or " |
1206 | "world-writable.", _PATH_PRIVSEP_CHROOT_DIR); | |
3cc54fbb | 1207 | } |
1208 | ||
f87f09aa | 1209 | /* Configuration looks good, so exit if in test mode. */ |
1210 | if (test_flag) | |
1211 | exit(0); | |
1212 | ||
018a5ea3 | 1213 | /* |
1214 | * Clear out any supplemental groups we may have inherited. This | |
1215 | * prevents inadvertent creation of files with bad modes (in the | |
aff51935 | 1216 | * portable version at least, it's certainly possible for PAM |
1217 | * to create a file, and we can't control the code in every | |
018a5ea3 | 1218 | * module which might be used). |
1219 | */ | |
1220 | if (setgroups(0, NULL) < 0) | |
1221 | debug("setgroups() failed: %.200s", strerror(errno)); | |
1222 | ||
b9a549d7 | 1223 | if (rexec_flag) { |
52e3daed | 1224 | rexec_argv = xcalloc(rexec_argc + 2, sizeof(char *)); |
b9a549d7 | 1225 | for (i = 0; i < rexec_argc; i++) { |
1226 | debug("rexec_argv[%d]='%s'", i, saved_argv[i]); | |
1227 | rexec_argv[i] = saved_argv[i]; | |
1228 | } | |
1229 | rexec_argv[rexec_argc] = "-R"; | |
1230 | rexec_argv[rexec_argc + 1] = NULL; | |
1231 | } | |
1232 | ||
a306f2dd | 1233 | /* Initialize the log (it is reinitialized below in case we forked). */ |
25c31d49 | 1234 | if (debug_flag && (!inetd_flag || rexeced_flag)) |
5260325f | 1235 | log_stderr = 1; |
1fe6a48f | 1236 | log_init(__progname, options.log_level, options.log_facility, log_stderr); |
5260325f | 1237 | |
a306f2dd | 1238 | /* |
1239 | * If not in debugging mode, and not started from inetd, disconnect | |
1240 | * from the controlling terminal, and fork. The original process | |
1241 | * exits. | |
1242 | */ | |
0b6fbf03 | 1243 | if (!(debug_flag || inetd_flag || no_daemon_flag)) { |
8efc0c15 | 1244 | #ifdef TIOCNOTTY |
5260325f | 1245 | int fd; |
8efc0c15 | 1246 | #endif /* TIOCNOTTY */ |
5260325f | 1247 | if (daemon(0, 0) < 0) |
1248 | fatal("daemon() failed: %.200s", strerror(errno)); | |
1249 | ||
1250 | /* Disconnect from the controlling tty. */ | |
8efc0c15 | 1251 | #ifdef TIOCNOTTY |
5ca51e19 | 1252 | fd = open(_PATH_TTY, O_RDWR | O_NOCTTY); |
5260325f | 1253 | if (fd >= 0) { |
1254 | (void) ioctl(fd, TIOCNOTTY, NULL); | |
1255 | close(fd); | |
1256 | } | |
8efc0c15 | 1257 | #endif /* TIOCNOTTY */ |
8efc0c15 | 1258 | } |
5260325f | 1259 | /* Reinitialize the log (because of the fork above). */ |
1fe6a48f | 1260 | log_init(__progname, options.log_level, options.log_facility, log_stderr); |
5260325f | 1261 | |
5260325f | 1262 | /* Initialize the random number generator. */ |
1263 | arc4random_stir(); | |
1264 | ||
1265 | /* Chdir to the root directory so that the current disk can be | |
1266 | unmounted if desired. */ | |
1267 | chdir("/"); | |
184eed6a | 1268 | |
1d3c30db | 1269 | /* ignore SIGPIPE */ |
1270 | signal(SIGPIPE, SIG_IGN); | |
5260325f | 1271 | |
5260325f | 1272 | /* Start listening for a socket, unless started from inetd. */ |
1273 | if (inetd_flag) { | |
b9a549d7 | 1274 | int fd; |
1275 | ||
4c8722d9 | 1276 | startup_pipe = -1; |
b9a549d7 | 1277 | if (rexeced_flag) { |
b250e837 | 1278 | close(REEXEC_CONFIG_PASS_FD); |
b9a549d7 | 1279 | sock_in = sock_out = dup(STDIN_FILENO); |
1280 | if (!debug_flag) { | |
b250e837 | 1281 | startup_pipe = dup(REEXEC_STARTUP_PIPE_FD); |
1282 | close(REEXEC_STARTUP_PIPE_FD); | |
b9a549d7 | 1283 | } |
1284 | } else { | |
1285 | sock_in = dup(STDIN_FILENO); | |
1286 | sock_out = dup(STDOUT_FILENO); | |
1287 | } | |
a306f2dd | 1288 | /* |
1289 | * We intentionally do not close the descriptors 0, 1, and 2 | |
b9a549d7 | 1290 | * as our code for setting the descriptors won't work if |
a306f2dd | 1291 | * ttyfd happens to be one of those. |
1292 | */ | |
b9a549d7 | 1293 | if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { |
1294 | dup2(fd, STDIN_FILENO); | |
1295 | dup2(fd, STDOUT_FILENO); | |
1296 | if (fd > STDOUT_FILENO) | |
1297 | close(fd); | |
1298 | } | |
5260325f | 1299 | debug("inetd sockets after dupping: %d, %d", sock_in, sock_out); |
b9a549d7 | 1300 | if ((options.protocol & SSH_PROTO_1) && |
1301 | sensitive_data.server_key == NULL) | |
cb7bd922 | 1302 | generate_ephemeral_server_key(); |
5260325f | 1303 | } else { |
48e671d5 | 1304 | for (ai = options.listen_addrs; ai; ai = ai->ai_next) { |
1305 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) | |
1306 | continue; | |
1307 | if (num_listen_socks >= MAX_LISTEN_SOCKS) | |
1308 | fatal("Too many listen sockets. " | |
1309 | "Enlarge MAX_LISTEN_SOCKS"); | |
945a9853 | 1310 | if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen, |
48e671d5 | 1311 | ntop, sizeof(ntop), strport, sizeof(strport), |
945a9853 | 1312 | NI_NUMERICHOST|NI_NUMERICSERV)) != 0) { |
1313 | error("getnameinfo failed: %.100s", | |
1314 | (ret != EAI_SYSTEM) ? gai_strerror(ret) : | |
1315 | strerror(errno)); | |
48e671d5 | 1316 | continue; |
1317 | } | |
1318 | /* Create socket for listening. */ | |
3e131a6d | 1319 | listen_sock = socket(ai->ai_family, ai->ai_socktype, |
1320 | ai->ai_protocol); | |
48e671d5 | 1321 | if (listen_sock < 0) { |
1322 | /* kernel may not support ipv6 */ | |
1323 | verbose("socket: %.100s", strerror(errno)); | |
1324 | continue; | |
1325 | } | |
170694d7 | 1326 | if (set_nonblock(listen_sock) == -1) { |
a666e3b1 | 1327 | close(listen_sock); |
1328 | continue; | |
1329 | } | |
48e671d5 | 1330 | /* |
facfd613 | 1331 | * Set socket options. |
1332 | * Allow local port reuse in TIME_WAIT. | |
48e671d5 | 1333 | */ |
facfd613 | 1334 | if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR, |
1335 | &on, sizeof(on)) == -1) | |
1336 | error("setsockopt SO_REUSEADDR: %s", strerror(errno)); | |
48e671d5 | 1337 | |
1338 | debug("Bind to port %s on %s.", strport, ntop); | |
1339 | ||
1340 | /* Bind the socket to the desired port. */ | |
32ced054 | 1341 | if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) { |
1342 | if (!ai->ai_next) | |
1343 | error("Bind to port %s on %s failed: %.200s.", | |
1344 | strport, ntop, strerror(errno)); | |
48e671d5 | 1345 | close(listen_sock); |
1346 | continue; | |
1347 | } | |
1348 | listen_socks[num_listen_socks] = listen_sock; | |
1349 | num_listen_socks++; | |
1350 | ||
1351 | /* Start listening on the port. */ | |
fce39749 | 1352 | if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0) |
9f513268 | 1353 | fatal("listen on [%s]:%s: %.100s", |
1354 | ntop, strport, strerror(errno)); | |
1355 | logit("Server listening on %s port %s.", ntop, strport); | |
5260325f | 1356 | } |
48e671d5 | 1357 | freeaddrinfo(options.listen_addrs); |
1358 | ||
1359 | if (!num_listen_socks) | |
1360 | fatal("Cannot bind any address."); | |
1361 | ||
3aca00a3 | 1362 | if (options.protocol & SSH_PROTO_1) |
1363 | generate_ephemeral_server_key(); | |
1364 | ||
1365 | /* | |
1366 | * Arrange to restart on SIGHUP. The handler needs | |
1367 | * listen_sock. | |
1368 | */ | |
1369 | signal(SIGHUP, sighup_handler); | |
1370 | ||
1371 | signal(SIGTERM, sigterm_handler); | |
1372 | signal(SIGQUIT, sigterm_handler); | |
1373 | ||
1374 | /* Arrange SIGCHLD to be caught. */ | |
1375 | signal(SIGCHLD, main_sigchld_handler); | |
1376 | ||
1377 | /* Write out the pid file after the sigterm handler is setup */ | |
5260325f | 1378 | if (!debug_flag) { |
aa3378df | 1379 | /* |
97fb6912 | 1380 | * Record our pid in /var/run/sshd.pid to make it |
1381 | * easier to kill the correct sshd. We don't want to | |
1382 | * do this before the bind above because the bind will | |
aa3378df | 1383 | * fail if there already is a daemon, and this will |
1384 | * overwrite any old pid in the file. | |
1385 | */ | |
3c62e7eb | 1386 | f = fopen(options.pid_file, "wb"); |
71b9ced0 | 1387 | if (f == NULL) { |
1388 | error("Couldn't create pid file \"%s\": %s", | |
1389 | options.pid_file, strerror(errno)); | |
1390 | } else { | |
c457707e | 1391 | fprintf(f, "%ld\n", (long) getpid()); |
5260325f | 1392 | fclose(f); |
1393 | } | |
8efc0c15 | 1394 | } |
5260325f | 1395 | |
48e671d5 | 1396 | /* setup fd set for listen */ |
089fbbd2 | 1397 | fdset = NULL; |
48e671d5 | 1398 | maxfd = 0; |
1399 | for (i = 0; i < num_listen_socks; i++) | |
1400 | if (listen_socks[i] > maxfd) | |
1401 | maxfd = listen_socks[i]; | |
089fbbd2 | 1402 | /* pipes connected to unauthenticated childs */ |
52e3daed | 1403 | startup_pipes = xcalloc(options.max_startups, sizeof(int)); |
089fbbd2 | 1404 | for (i = 0; i < options.max_startups; i++) |
1405 | startup_pipes[i] = -1; | |
48e671d5 | 1406 | |
aa3378df | 1407 | /* |
1408 | * Stay listening for connections until the system crashes or | |
1409 | * the daemon is killed with a signal. | |
1410 | */ | |
5260325f | 1411 | for (;;) { |
1412 | if (received_sighup) | |
1413 | sighup_restart(); | |
089fbbd2 | 1414 | if (fdset != NULL) |
1415 | xfree(fdset); | |
52e3daed | 1416 | fdset = (fd_set *)xcalloc(howmany(maxfd + 1, NFDBITS), |
1417 | sizeof(fd_mask)); | |
089fbbd2 | 1418 | |
48e671d5 | 1419 | for (i = 0; i < num_listen_socks; i++) |
1420 | FD_SET(listen_socks[i], fdset); | |
089fbbd2 | 1421 | for (i = 0; i < options.max_startups; i++) |
1422 | if (startup_pipes[i] != -1) | |
1423 | FD_SET(startup_pipes[i], fdset); | |
1424 | ||
1425 | /* Wait in select until there is a connection. */ | |
59c97189 | 1426 | ret = select(maxfd+1, fdset, NULL, NULL, NULL); |
1427 | if (ret < 0 && errno != EINTR) | |
1428 | error("select: %.100s", strerror(errno)); | |
c9130033 | 1429 | if (received_sigterm) { |
bbe88b6d | 1430 | logit("Received signal %d; terminating.", |
010f9726 | 1431 | (int) received_sigterm); |
c9130033 | 1432 | close_listen_socks(); |
1433 | unlink(options.pid_file); | |
1434 | exit(255); | |
1435 | } | |
59c97189 | 1436 | if (key_used && key_do_regen) { |
cb7bd922 | 1437 | generate_ephemeral_server_key(); |
59c97189 | 1438 | key_used = 0; |
1439 | key_do_regen = 0; | |
48e671d5 | 1440 | } |
59c97189 | 1441 | if (ret < 0) |
1442 | continue; | |
1443 | ||
089fbbd2 | 1444 | for (i = 0; i < options.max_startups; i++) |
1445 | if (startup_pipes[i] != -1 && | |
1446 | FD_ISSET(startup_pipes[i], fdset)) { | |
1447 | /* | |
1448 | * the read end of the pipe is ready | |
1449 | * if the child has closed the pipe | |
8abcdba4 | 1450 | * after successful authentication |
089fbbd2 | 1451 | * or if the child has died |
1452 | */ | |
1453 | close(startup_pipes[i]); | |
1454 | startup_pipes[i] = -1; | |
1455 | startups--; | |
1456 | } | |
48e671d5 | 1457 | for (i = 0; i < num_listen_socks; i++) { |
1458 | if (!FD_ISSET(listen_socks[i], fdset)) | |
5260325f | 1459 | continue; |
089fbbd2 | 1460 | fromlen = sizeof(from); |
3efa8ea9 | 1461 | newsock = accept(listen_socks[i], |
1462 | (struct sockaddr *)&from, &fromlen); | |
089fbbd2 | 1463 | if (newsock < 0) { |
1464 | if (errno != EINTR && errno != EWOULDBLOCK) | |
1465 | error("accept: %.100s", strerror(errno)); | |
1466 | continue; | |
1467 | } | |
170694d7 | 1468 | if (unset_nonblock(newsock) == -1) { |
a666e3b1 | 1469 | close(newsock); |
1470 | continue; | |
1471 | } | |
c345cf9d | 1472 | if (drop_connection(startups) == 1) { |
1473 | debug("drop connection #%d", startups); | |
089fbbd2 | 1474 | close(newsock); |
1475 | continue; | |
1476 | } | |
1477 | if (pipe(startup_p) == -1) { | |
1478 | close(newsock); | |
1479 | continue; | |
1480 | } | |
1481 | ||
b9a549d7 | 1482 | if (rexec_flag && socketpair(AF_UNIX, |
1483 | SOCK_STREAM, 0, config_s) == -1) { | |
1484 | error("reexec socketpair: %s", | |
1485 | strerror(errno)); | |
1486 | close(newsock); | |
1487 | close(startup_p[0]); | |
1488 | close(startup_p[1]); | |
1489 | continue; | |
1490 | } | |
1491 | ||
089fbbd2 | 1492 | for (j = 0; j < options.max_startups; j++) |
1493 | if (startup_pipes[j] == -1) { | |
1494 | startup_pipes[j] = startup_p[0]; | |
1495 | if (maxfd < startup_p[0]) | |
1496 | maxfd = startup_p[0]; | |
1497 | startups++; | |
1498 | break; | |
1499 | } | |
2b87da3b | 1500 | |
aa3378df | 1501 | /* |
089fbbd2 | 1502 | * Got connection. Fork a child to handle it, unless |
1503 | * we are in debugging mode. | |
aa3378df | 1504 | */ |
089fbbd2 | 1505 | if (debug_flag) { |
aa3378df | 1506 | /* |
089fbbd2 | 1507 | * In debugging mode. Close the listening |
1508 | * socket, and start processing the | |
1509 | * connection without forking. | |
aa3378df | 1510 | */ |
089fbbd2 | 1511 | debug("Server will not fork when running in debugging mode."); |
48e671d5 | 1512 | close_listen_socks(); |
5260325f | 1513 | sock_in = newsock; |
1514 | sock_out = newsock; | |
b9a549d7 | 1515 | close(startup_p[0]); |
1516 | close(startup_p[1]); | |
5540ea9b | 1517 | startup_pipe = -1; |
3f7a7e4a | 1518 | pid = getpid(); |
b9a549d7 | 1519 | if (rexec_flag) { |
1520 | send_rexec_state(config_s[0], | |
1521 | &cfg); | |
1522 | close(config_s[0]); | |
1523 | } | |
5260325f | 1524 | break; |
089fbbd2 | 1525 | } else { |
1526 | /* | |
1527 | * Normal production daemon. Fork, and have | |
1528 | * the child process the connection. The | |
1529 | * parent continues listening. | |
1530 | */ | |
1531 | if ((pid = fork()) == 0) { | |
1532 | /* | |
3efa8ea9 | 1533 | * Child. Close the listening and |
1534 | * max_startup sockets. Start using | |
1535 | * the accepted socket. Reinitialize | |
1536 | * logging (since our pid has changed). | |
1537 | * We break out of the loop to handle | |
089fbbd2 | 1538 | * the connection. |
1539 | */ | |
1540 | startup_pipe = startup_p[1]; | |
7ace8c3b | 1541 | close_startup_pipes(); |
089fbbd2 | 1542 | close_listen_socks(); |
1543 | sock_in = newsock; | |
1544 | sock_out = newsock; | |
3efa8ea9 | 1545 | log_init(__progname, |
1546 | options.log_level, | |
1547 | options.log_facility, | |
1548 | log_stderr); | |
9216f89c | 1549 | if (rexec_flag) |
1550 | close(config_s[0]); | |
089fbbd2 | 1551 | break; |
1552 | } | |
5260325f | 1553 | } |
5260325f | 1554 | |
089fbbd2 | 1555 | /* Parent. Stay in the loop. */ |
1556 | if (pid < 0) | |
1557 | error("fork: %.100s", strerror(errno)); | |
1558 | else | |
c457707e | 1559 | debug("Forked child %ld.", (long)pid); |
5260325f | 1560 | |
089fbbd2 | 1561 | close(startup_p[1]); |
5260325f | 1562 | |
b9a549d7 | 1563 | if (rexec_flag) { |
1564 | send_rexec_state(config_s[0], &cfg); | |
1565 | close(config_s[0]); | |
1566 | close(config_s[1]); | |
1567 | } | |
1568 | ||
3efa8ea9 | 1569 | /* |
1570 | * Mark that the key has been used (it | |
1571 | * was "given" to the child). | |
1572 | */ | |
59c97189 | 1573 | if ((options.protocol & SSH_PROTO_1) && |
1574 | key_used == 0) { | |
1575 | /* Schedule server key regeneration alarm. */ | |
f00d1f78 | 1576 | signal(SIGALRM, key_regeneration_alarm); |
59c97189 | 1577 | alarm(options.key_regeneration_time); |
1578 | key_used = 1; | |
1579 | } | |
5260325f | 1580 | |
089fbbd2 | 1581 | arc4random_stir(); |
089fbbd2 | 1582 | close(newsock); |
1583 | } | |
48e671d5 | 1584 | /* child process check (or debug mode) */ |
1585 | if (num_listen_socks < 0) | |
1586 | break; | |
5260325f | 1587 | } |
1588 | } | |
8efc0c15 | 1589 | |
5260325f | 1590 | /* This is the child processing a new connection. */ |
cc120685 | 1591 | setproctitle("%s", "[accepted]"); |
5260325f | 1592 | |
8b758bd2 | 1593 | /* |
1594 | * Create a new session and process group since the 4.4BSD | |
1595 | * setlogin() affects the entire process group. We don't | |
1596 | * want the child to be able to affect the parent. | |
1597 | */ | |
1598 | #if !defined(SSHD_ACQUIRES_CTTY) | |
1599 | /* | |
1600 | * If setsid is called, on some platforms sshd will later acquire a | |
1601 | * controlling terminal which will result in "could not set | |
1602 | * controlling tty" errors. | |
1603 | */ | |
1604 | if (!debug_flag && !inetd_flag && setsid() < 0) | |
1605 | error("setsid: %.100s", strerror(errno)); | |
1606 | #endif | |
1607 | ||
b9a549d7 | 1608 | if (rexec_flag) { |
1609 | int fd; | |
1610 | ||
b250e837 | 1611 | debug("rexec start in %d out %d newsock %d pipe %d sock %d", |
1612 | sock_in, sock_out, newsock, startup_pipe, config_s[0]); | |
b9a549d7 | 1613 | dup2(newsock, STDIN_FILENO); |
1614 | dup2(STDIN_FILENO, STDOUT_FILENO); | |
1615 | if (startup_pipe == -1) | |
b250e837 | 1616 | close(REEXEC_STARTUP_PIPE_FD); |
b9a549d7 | 1617 | else |
b250e837 | 1618 | dup2(startup_pipe, REEXEC_STARTUP_PIPE_FD); |
b9a549d7 | 1619 | |
b250e837 | 1620 | dup2(config_s[1], REEXEC_CONFIG_PASS_FD); |
b9a549d7 | 1621 | close(config_s[1]); |
ad148c04 | 1622 | if (startup_pipe != -1) |
1623 | close(startup_pipe); | |
b250e837 | 1624 | |
b9a549d7 | 1625 | execv(rexec_argv[0], rexec_argv); |
1626 | ||
1627 | /* Reexec has failed, fall back and continue */ | |
1628 | error("rexec of %s failed: %s", rexec_argv[0], strerror(errno)); | |
b250e837 | 1629 | recv_rexec_state(REEXEC_CONFIG_PASS_FD, NULL); |
b9a549d7 | 1630 | log_init(__progname, options.log_level, |
1631 | options.log_facility, log_stderr); | |
1632 | ||
1633 | /* Clean up fds */ | |
b250e837 | 1634 | startup_pipe = REEXEC_STARTUP_PIPE_FD; |
b9a549d7 | 1635 | close(config_s[1]); |
b250e837 | 1636 | close(REEXEC_CONFIG_PASS_FD); |
1637 | newsock = sock_out = sock_in = dup(STDIN_FILENO); | |
b9a549d7 | 1638 | if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { |
1639 | dup2(fd, STDIN_FILENO); | |
1640 | dup2(fd, STDOUT_FILENO); | |
1641 | if (fd > STDERR_FILENO) | |
1642 | close(fd); | |
1643 | } | |
b250e837 | 1644 | debug("rexec cleanup in %d out %d newsock %d pipe %d sock %d", |
1645 | sock_in, sock_out, newsock, startup_pipe, config_s[0]); | |
b9a549d7 | 1646 | } |
1647 | ||
aa3378df | 1648 | /* |
1649 | * Disable the key regeneration alarm. We will not regenerate the | |
1650 | * key since we are no longer in a position to give it to anyone. We | |
1651 | * will not restart on SIGHUP since it no longer makes sense. | |
1652 | */ | |
5260325f | 1653 | alarm(0); |
1654 | signal(SIGALRM, SIG_DFL); | |
1655 | signal(SIGHUP, SIG_DFL); | |
1656 | signal(SIGTERM, SIG_DFL); | |
1657 | signal(SIGQUIT, SIG_DFL); | |
1658 | signal(SIGCHLD, SIG_DFL); | |
9aaf9be4 | 1659 | signal(SIGINT, SIG_DFL); |
5260325f | 1660 | |
aa3378df | 1661 | /* |
1662 | * Register our connection. This turns encryption off because we do | |
1663 | * not have a key. | |
1664 | */ | |
5260325f | 1665 | packet_set_connection(sock_in, sock_out); |
07200973 | 1666 | packet_set_server(); |
5260325f | 1667 | |
7c3bc5a2 | 1668 | /* Set SO_KEEPALIVE if requested. */ |
1669 | if (options.tcp_keep_alive && packet_connection_is_on_socket() && | |
1670 | setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) < 0) | |
1671 | error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); | |
1672 | ||
29798ed0 | 1673 | if ((remote_port = get_remote_port()) < 0) { |
1674 | debug("get_remote_port failed"); | |
1675 | cleanup_exit(255); | |
1676 | } | |
3a85986d | 1677 | |
1678 | /* | |
1679 | * We use get_canonical_hostname with usedns = 0 instead of | |
1680 | * get_remote_ipaddr here so IP options will be checked. | |
1681 | */ | |
211f229e | 1682 | (void) get_canonical_hostname(0); |
1683 | /* | |
1684 | * The rest of the code depends on the fact that | |
1685 | * get_remote_ipaddr() caches the remote ip, even if | |
1686 | * the socket goes away. | |
1687 | */ | |
1688 | remote_ip = get_remote_ipaddr(); | |
5260325f | 1689 | |
6039eeef | 1690 | #ifdef SSH_AUDIT_EVENTS |
c00e4d75 | 1691 | audit_connection_from(remote_ip, remote_port); |
1692 | #endif | |
5260325f | 1693 | #ifdef LIBWRAP |
ac28afd8 | 1694 | /* Check whether logins are denied from this host. */ |
33e5359c | 1695 | if (packet_connection_is_on_socket()) { |
5260325f | 1696 | struct request_info req; |
8efc0c15 | 1697 | |
8fbc356d | 1698 | request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0); |
5260325f | 1699 | fromhost(&req); |
8efc0c15 | 1700 | |
5260325f | 1701 | if (!hosts_access(&req)) { |
ac28afd8 | 1702 | debug("Connection refused by tcp wrapper"); |
563834bb | 1703 | refuse(&req); |
ac28afd8 | 1704 | /* NOTREACHED */ |
1705 | fatal("libwrap refuse returns"); | |
5260325f | 1706 | } |
8efc0c15 | 1707 | } |
48e671d5 | 1708 | #endif /* LIBWRAP */ |
ac28afd8 | 1709 | |
5260325f | 1710 | /* Log the connection. */ |
1711 | verbose("Connection from %.500s port %d", remote_ip, remote_port); | |
8efc0c15 | 1712 | |
aa3378df | 1713 | /* |
7b9b0103 | 1714 | * We don't want to listen forever unless the other side |
aa3378df | 1715 | * successfully authenticates itself. So we set up an alarm which is |
1716 | * cleared after successful authentication. A limit of zero | |
7b9b0103 | 1717 | * indicates no limit. Note that we don't set the alarm in debugging |
aa3378df | 1718 | * mode; it is just annoying to have the server exit just when you |
1719 | * are about to discover the bug. | |
1720 | */ | |
f00d1f78 | 1721 | signal(SIGALRM, grace_alarm_handler); |
5260325f | 1722 | if (!debug_flag) |
1723 | alarm(options.login_grace_time); | |
1724 | ||
7368a6c8 | 1725 | sshd_exchange_identification(sock_in, sock_out); |
0598d99d | 1726 | |
5260325f | 1727 | packet_set_nonblocking(); |
1728 | ||
2362db19 | 1729 | /* allocate authentication context */ |
52e3daed | 1730 | authctxt = xcalloc(1, sizeof(*authctxt)); |
2362db19 | 1731 | |
1b394137 | 1732 | authctxt->loginmsg = &loginmsg; |
1733 | ||
2362db19 | 1734 | /* XXX global for cleanup, access from other modules */ |
1735 | the_authctxt = authctxt; | |
1736 | ||
022487ce | 1737 | /* prepare buffer to collect messages to display to user after login */ |
1738 | buffer_init(&loginmsg); | |
1739 | ||
324bf712 | 1740 | if (use_privsep) |
2362db19 | 1741 | if (privsep_preauth(authctxt) == 1) |
324bf712 | 1742 | goto authenticated; |
1853d1ef | 1743 | |
7b2ea3a1 | 1744 | /* perform the key exchange */ |
7b2ea3a1 | 1745 | /* authenticate user and start session */ |
e78a59f5 | 1746 | if (compat20) { |
1747 | do_ssh2_kex(); | |
2362db19 | 1748 | do_authentication2(authctxt); |
e78a59f5 | 1749 | } else { |
1750 | do_ssh1_kex(); | |
2362db19 | 1751 | do_authentication(authctxt); |
e78a59f5 | 1752 | } |
324bf712 | 1753 | /* |
1754 | * If we use privilege separation, the unprivileged child transfers | |
1755 | * the current keystate and exits | |
1756 | */ | |
1757 | if (use_privsep) { | |
b5a28cbc | 1758 | mm_send_keystate(pmonitor); |
1853d1ef | 1759 | exit(0); |
324bf712 | 1760 | } |
1853d1ef | 1761 | |
1762 | authenticated: | |
678143bd | 1763 | /* |
1764 | * Cancel the alarm we set to limit the time taken for | |
1765 | * authentication. | |
1766 | */ | |
1767 | alarm(0); | |
1768 | signal(SIGALRM, SIG_DFL); | |
1769 | if (startup_pipe != -1) { | |
1770 | close(startup_pipe); | |
1771 | startup_pipe = -1; | |
1772 | } | |
1773 | ||
6039eeef | 1774 | #ifdef SSH_AUDIT_EVENTS |
1775 | audit_event(SSH_AUTH_SUCCESS); | |
c00e4d75 | 1776 | #endif |
1777 | ||
762715ce | 1778 | /* |
1853d1ef | 1779 | * In privilege separation, we fork another child and prepare |
1780 | * file descriptor passing. | |
1781 | */ | |
1782 | if (use_privsep) { | |
324bf712 | 1783 | privsep_postauth(authctxt); |
1784 | /* the monitor process [priv] will not return */ | |
1853d1ef | 1785 | if (!compat20) |
1786 | destroy_sensitive_data(); | |
1787 | } | |
1b34c1b3 | 1788 | |
2362db19 | 1789 | /* Start session. */ |
1b34c1b3 | 1790 | do_authenticated(authctxt); |
1791 | ||
63284fbb | 1792 | /* The connection has been terminated. */ |
1793 | verbose("Closing connection to %.100s", remote_ip); | |
8efc0c15 | 1794 | |
d94aa2ae | 1795 | #ifdef USE_PAM |
7fceb20d | 1796 | if (options.use_pam) |
1797 | finish_pam(); | |
d94aa2ae | 1798 | #endif /* USE_PAM */ |
8efc0c15 | 1799 | |
2b0c0925 | 1800 | #ifdef SSH_AUDIT_EVENTS |
1801 | PRIVSEP(audit_event(SSH_CONNECTION_CLOSE)); | |
1802 | #endif | |
1803 | ||
5260325f | 1804 | packet_close(); |
1853d1ef | 1805 | |
1806 | if (use_privsep) | |
1807 | mm_terminate(); | |
1808 | ||
5260325f | 1809 | exit(0); |
1810 | } | |
8efc0c15 | 1811 | |
4f08e98d | 1812 | /* |
1813 | * Decrypt session_key_int using our private server key and private host key | |
1814 | * (key with larger modulus first). | |
1815 | */ | |
1853d1ef | 1816 | int |
4f08e98d | 1817 | ssh1_session_key(BIGNUM *session_key_int) |
1818 | { | |
1819 | int rsafail = 0; | |
1820 | ||
3efa8ea9 | 1821 | if (BN_cmp(sensitive_data.server_key->rsa->n, |
1822 | sensitive_data.ssh1_host_key->rsa->n) > 0) { | |
4f08e98d | 1823 | /* Server key has bigger modulus. */ |
1824 | if (BN_num_bits(sensitive_data.server_key->rsa->n) < | |
3efa8ea9 | 1825 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + |
1826 | SSH_KEY_BITS_RESERVED) { | |
1827 | fatal("do_connection: %s: " | |
1828 | "server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d", | |
4f08e98d | 1829 | get_remote_ipaddr(), |
1830 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
1831 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), | |
1832 | SSH_KEY_BITS_RESERVED); | |
1833 | } | |
1834 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1835 | sensitive_data.server_key->rsa) <= 0) | |
1836 | rsafail++; | |
1837 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1838 | sensitive_data.ssh1_host_key->rsa) <= 0) | |
1839 | rsafail++; | |
1840 | } else { | |
1841 | /* Host key has bigger modulus (or they are equal). */ | |
1842 | if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) < | |
3efa8ea9 | 1843 | BN_num_bits(sensitive_data.server_key->rsa->n) + |
1844 | SSH_KEY_BITS_RESERVED) { | |
1845 | fatal("do_connection: %s: " | |
1846 | "host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d", | |
4f08e98d | 1847 | get_remote_ipaddr(), |
1848 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), | |
1849 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
1850 | SSH_KEY_BITS_RESERVED); | |
1851 | } | |
1852 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1853 | sensitive_data.ssh1_host_key->rsa) < 0) | |
1854 | rsafail++; | |
1855 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1856 | sensitive_data.server_key->rsa) < 0) | |
1857 | rsafail++; | |
1858 | } | |
1859 | return (rsafail); | |
1860 | } | |
5260325f | 1861 | /* |
7b2ea3a1 | 1862 | * SSH1 key exchange |
5260325f | 1863 | */ |
396c147e | 1864 | static void |
1e3b8b07 | 1865 | do_ssh1_kex(void) |
8efc0c15 | 1866 | { |
5260325f | 1867 | int i, len; |
46aa2d1f | 1868 | int rsafail = 0; |
5260325f | 1869 | BIGNUM *session_key_int; |
1e3b8b07 | 1870 | u_char session_key[SSH_SESSION_KEY_LENGTH]; |
1871 | u_char cookie[8]; | |
1872 | u_int cipher_type, auth_mask, protocol_flags; | |
7fdc56c5 | 1873 | u_int32_t rnd = 0; |
5260325f | 1874 | |
aa3378df | 1875 | /* |
1876 | * Generate check bytes that the client must send back in the user | |
1877 | * packet in order for it to be accepted; this is used to defy ip | |
1878 | * spoofing attacks. Note that this only works against somebody | |
1879 | * doing IP spoofing from a remote machine; any machine on the local | |
1880 | * network can still see outgoing packets and catch the random | |
1881 | * cookie. This only affects rhosts authentication, and this is one | |
1882 | * of the reasons why it is inherently insecure. | |
1883 | */ | |
5260325f | 1884 | for (i = 0; i < 8; i++) { |
1885 | if (i % 4 == 0) | |
7fdc56c5 | 1886 | rnd = arc4random(); |
1887 | cookie[i] = rnd & 0xff; | |
1888 | rnd >>= 8; | |
5260325f | 1889 | } |
1890 | ||
aa3378df | 1891 | /* |
1892 | * Send our public key. We include in the packet 64 bits of random | |
1893 | * data that must be matched in the reply in order to prevent IP | |
1894 | * spoofing. | |
1895 | */ | |
5260325f | 1896 | packet_start(SSH_SMSG_PUBLIC_KEY); |
1897 | for (i = 0; i < 8; i++) | |
7b2ea3a1 | 1898 | packet_put_char(cookie[i]); |
5260325f | 1899 | |
1900 | /* Store our public server RSA key. */ | |
fa08c86b | 1901 | packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n)); |
1902 | packet_put_bignum(sensitive_data.server_key->rsa->e); | |
1903 | packet_put_bignum(sensitive_data.server_key->rsa->n); | |
5260325f | 1904 | |
1905 | /* Store our public host RSA key. */ | |
fa08c86b | 1906 | packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); |
1907 | packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e); | |
1908 | packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n); | |
5260325f | 1909 | |
1910 | /* Put protocol flags. */ | |
1911 | packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN); | |
1912 | ||
1913 | /* Declare which ciphers we support. */ | |
94ec8c6b | 1914 | packet_put_int(cipher_mask_ssh1(0)); |
5260325f | 1915 | |
1916 | /* Declare supported authentication types. */ | |
1917 | auth_mask = 0; | |
5260325f | 1918 | if (options.rhosts_rsa_authentication) |
1919 | auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA; | |
1920 | if (options.rsa_authentication) | |
1921 | auth_mask |= 1 << SSH_AUTH_RSA; | |
5ba55ada | 1922 | if (options.challenge_response_authentication == 1) |
5260325f | 1923 | auth_mask |= 1 << SSH_AUTH_TIS; |
5260325f | 1924 | if (options.password_authentication) |
1925 | auth_mask |= 1 << SSH_AUTH_PASSWORD; | |
1926 | packet_put_int(auth_mask); | |
1927 | ||
1928 | /* Send the packet and wait for it to be sent. */ | |
1929 | packet_send(); | |
1930 | packet_write_wait(); | |
1931 | ||
fa08c86b | 1932 | debug("Sent %d bit server key and %d bit host key.", |
1933 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
1934 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); | |
5260325f | 1935 | |
1936 | /* Read clients reply (cipher type and session key). */ | |
54a5250f | 1937 | packet_read_expect(SSH_CMSG_SESSION_KEY); |
5260325f | 1938 | |
2d86a6cc | 1939 | /* Get cipher type and check whether we accept this. */ |
5260325f | 1940 | cipher_type = packet_get_char(); |
1941 | ||
94ec8c6b | 1942 | if (!(cipher_mask_ssh1(0) & (1 << cipher_type))) |
2d86a6cc | 1943 | packet_disconnect("Warning: client selects unsupported cipher."); |
1944 | ||
5260325f | 1945 | /* Get check bytes from the packet. These must match those we |
1946 | sent earlier with the public key packet. */ | |
1947 | for (i = 0; i < 8; i++) | |
7b2ea3a1 | 1948 | if (cookie[i] != packet_get_char()) |
5260325f | 1949 | packet_disconnect("IP Spoofing check bytes do not match."); |
1950 | ||
1951 | debug("Encryption type: %.200s", cipher_name(cipher_type)); | |
1952 | ||
1953 | /* Get the encrypted integer. */ | |
b775c6f2 | 1954 | if ((session_key_int = BN_new()) == NULL) |
1955 | fatal("do_ssh1_kex: BN_new failed"); | |
20b279e6 | 1956 | packet_get_bignum(session_key_int); |
5260325f | 1957 | |
5260325f | 1958 | protocol_flags = packet_get_int(); |
1959 | packet_set_protocol_flags(protocol_flags); | |
95500969 | 1960 | packet_check_eom(); |
5260325f | 1961 | |
4f08e98d | 1962 | /* Decrypt session_key_int using host/server keys */ |
1853d1ef | 1963 | rsafail = PRIVSEP(ssh1_session_key(session_key_int)); |
1964 | ||
aa3378df | 1965 | /* |
1966 | * Extract session key from the decrypted integer. The key is in the | |
1967 | * least significant 256 bits of the integer; the first byte of the | |
1968 | * key is in the highest bits. | |
1969 | */ | |
46aa2d1f | 1970 | if (!rsafail) { |
1971 | BN_mask_bits(session_key_int, sizeof(session_key) * 8); | |
1972 | len = BN_num_bytes(session_key_int); | |
2ceb8101 | 1973 | if (len < 0 || (u_int)len > sizeof(session_key)) { |
46aa2d1f | 1974 | error("do_connection: bad session key len from %s: " |
5ca51e19 | 1975 | "session_key_int %d > sizeof(session_key) %lu", |
1976 | get_remote_ipaddr(), len, (u_long)sizeof(session_key)); | |
46aa2d1f | 1977 | rsafail++; |
1978 | } else { | |
1979 | memset(session_key, 0, sizeof(session_key)); | |
1980 | BN_bn2bin(session_key_int, | |
1981 | session_key + sizeof(session_key) - len); | |
00be5382 | 1982 | |
8bbf1fa6 | 1983 | derive_ssh1_session_id( |
f2107e97 | 1984 | sensitive_data.ssh1_host_key->rsa->n, |
8bbf1fa6 | 1985 | sensitive_data.server_key->rsa->n, |
1986 | cookie, session_id); | |
00be5382 | 1987 | /* |
1988 | * Xor the first 16 bytes of the session key with the | |
1989 | * session id. | |
1990 | */ | |
1991 | for (i = 0; i < 16; i++) | |
1992 | session_key[i] ^= session_id[i]; | |
46aa2d1f | 1993 | } |
1994 | } | |
1995 | if (rsafail) { | |
00be5382 | 1996 | int bytes = BN_num_bytes(session_key_int); |
f6b1ba8f | 1997 | u_char *buf = xmalloc(bytes); |
00be5382 | 1998 | MD5_CTX md; |
1999 | ||
bbe88b6d | 2000 | logit("do_connection: generating a fake encryption key"); |
00be5382 | 2001 | BN_bn2bin(session_key_int, buf); |
2002 | MD5_Init(&md); | |
2003 | MD5_Update(&md, buf, bytes); | |
2004 | MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); | |
2005 | MD5_Final(session_key, &md); | |
2006 | MD5_Init(&md); | |
2007 | MD5_Update(&md, session_key, 16); | |
2008 | MD5_Update(&md, buf, bytes); | |
2009 | MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); | |
2010 | MD5_Final(session_key + 16, &md); | |
2011 | memset(buf, 0, bytes); | |
2012 | xfree(buf); | |
0572fe75 | 2013 | for (i = 0; i < 16; i++) |
2014 | session_id[i] = session_key[i] ^ session_key[i + 16]; | |
46aa2d1f | 2015 | } |
1853d1ef | 2016 | /* Destroy the private and public keys. No longer. */ |
63284fbb | 2017 | destroy_sensitive_data(); |
00be5382 | 2018 | |
1853d1ef | 2019 | if (use_privsep) |
2020 | mm_ssh1_session_id(session_id); | |
2021 | ||
7b2ea3a1 | 2022 | /* Destroy the decrypted integer. It is no longer needed. */ |
2023 | BN_clear_free(session_key_int); | |
2024 | ||
5260325f | 2025 | /* Set the session key. From this on all communications will be encrypted. */ |
2026 | packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type); | |
2027 | ||
2028 | /* Destroy our copy of the session key. It is no longer needed. */ | |
2029 | memset(session_key, 0, sizeof(session_key)); | |
2030 | ||
2031 | debug("Received session key; encryption turned on."); | |
2032 | ||
c242fc96 | 2033 | /* Send an acknowledgment packet. Note that this packet is sent encrypted. */ |
5260325f | 2034 | packet_start(SSH_SMSG_SUCCESS); |
2035 | packet_send(); | |
2036 | packet_write_wait(); | |
5260325f | 2037 | } |
e78a59f5 | 2038 | |
2039 | /* | |
2040 | * SSH2 key exchange: diffie-hellman-group1-sha1 | |
2041 | */ | |
396c147e | 2042 | static void |
1e3b8b07 | 2043 | do_ssh2_kex(void) |
e78a59f5 | 2044 | { |
e78a59f5 | 2045 | Kex *kex; |
e78a59f5 | 2046 | |
a8be9f80 | 2047 | if (options.ciphers != NULL) { |
6ae2364d | 2048 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = |
a8be9f80 | 2049 | myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; |
2050 | } | |
1ad64a93 | 2051 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = |
2052 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]); | |
2053 | myproposal[PROPOSAL_ENC_ALGS_STOC] = | |
2054 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); | |
2055 | ||
b2552997 | 2056 | if (options.macs != NULL) { |
2057 | myproposal[PROPOSAL_MAC_ALGS_CTOS] = | |
2058 | myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; | |
2059 | } | |
07200973 | 2060 | if (options.compression == COMP_NONE) { |
636f76ca | 2061 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = |
2062 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "none"; | |
07200973 | 2063 | } else if (options.compression == COMP_DELAYED) { |
2064 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = | |
2065 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com"; | |
636f76ca | 2066 | } |
3efa8ea9 | 2067 | |
fa08c86b | 2068 | myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = list_hostkey_types(); |
2069 | ||
7a37c112 | 2070 | /* start key exchange */ |
d8ee838b | 2071 | kex = kex_setup(myproposal); |
98a58eda | 2072 | kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server; |
41e5bd9a | 2073 | kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server; |
98a58eda | 2074 | kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; |
2ff8003a | 2075 | kex->kex[KEX_DH_GEX_SHA256] = kexgex_server; |
a5c9ffdb | 2076 | kex->server = 1; |
2077 | kex->client_version_string=client_version_string; | |
2078 | kex->server_version_string=server_version_string; | |
2079 | kex->load_host_key=&get_hostkey_by_type; | |
1853d1ef | 2080 | kex->host_key_index=&get_hostkey_index; |
94ec8c6b | 2081 | |
7a37c112 | 2082 | xxx_kex = kex; |
2083 | ||
c422989b | 2084 | dispatch_run(DISPATCH_BLOCK, &kex->done, kex); |
94ec8c6b | 2085 | |
d1ac6175 | 2086 | session_id2 = kex->session_id; |
2087 | session_id2_len = kex->session_id_len; | |
2088 | ||
94ec8c6b | 2089 | #ifdef DEBUG_KEXDH |
2090 | /* send 1st encrypted/maced/compressed message */ | |
2091 | packet_start(SSH2_MSG_IGNORE); | |
2092 | packet_put_cstring("markus"); | |
2093 | packet_send(); | |
2094 | packet_write_wait(); | |
2095 | #endif | |
a5c9ffdb | 2096 | debug("KEX done"); |
e78a59f5 | 2097 | } |
2362db19 | 2098 | |
2099 | /* server specific fatal cleanup */ | |
2100 | void | |
2101 | cleanup_exit(int i) | |
2102 | { | |
2103 | if (the_authctxt) | |
2104 | do_cleanup(the_authctxt); | |
6039eeef | 2105 | #ifdef SSH_AUDIT_EVENTS |
c00e4d75 | 2106 | /* done after do_cleanup so it can cancel the PAM auth 'thread' */ |
2107 | if (!use_privsep || mm_is_monitor()) | |
6039eeef | 2108 | audit_event(SSH_CONNECTION_ABANDON); |
c00e4d75 | 2109 | #endif |
2362db19 | 2110 | _exit(i); |
2111 | } |