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cf851879 | 1 | /* $OpenBSD: sshd.c,v 1.342 2006/08/01 23:22:48 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> |
e264ac72 | 53 | #ifdef HAVE_SYS_TIME_H |
54 | # include <sys/time.h> | |
55 | #endif | |
aa2eae64 | 56 | #include <sys/wait.h> |
a75f5360 | 57 | |
028094f4 | 58 | #include <errno.h> |
d3221cca | 59 | #include <fcntl.h> |
28cb0a43 | 60 | #include <netdb.h> |
b5b88c19 | 61 | #ifdef HAVE_PATHS_H |
a75f5360 | 62 | #include <paths.h> |
b5b88c19 | 63 | #endif |
22bbb3e6 | 64 | #include <grp.h> |
b1842393 | 65 | #include <pwd.h> |
ada68823 | 66 | #include <signal.h> |
cf851879 | 67 | #include <stdio.h> |
ffa517a8 | 68 | #include <stdlib.h> |
00146caa | 69 | #include <string.h> |
8efc0c15 | 70 | |
42f11eb2 | 71 | #include <openssl/dh.h> |
72 | #include <openssl/bn.h> | |
436c347c | 73 | #include <openssl/md5.h> |
1853d1ef | 74 | #include <openssl/rand.h> |
6e879cb4 | 75 | #ifdef HAVE_SECUREWARE |
76 | #include <sys/security.h> | |
77 | #include <prot.h> | |
78 | #endif | |
42f11eb2 | 79 | |
80 | #include "ssh.h" | |
81 | #include "ssh1.h" | |
82 | #include "ssh2.h" | |
8efc0c15 | 83 | #include "xmalloc.h" |
84 | #include "rsa.h" | |
1729c161 | 85 | #include "sshpty.h" |
8efc0c15 | 86 | #include "packet.h" |
42f11eb2 | 87 | #include "log.h" |
8efc0c15 | 88 | #include "servconf.h" |
89 | #include "uidswap.h" | |
90 | #include "compat.h" | |
7368a6c8 | 91 | #include "buffer.h" |
b9a549d7 | 92 | #include "bufaux.h" |
42f11eb2 | 93 | #include "cipher.h" |
e78a59f5 | 94 | #include "kex.h" |
7368a6c8 | 95 | #include "key.h" |
94ec8c6b | 96 | #include "dh.h" |
e78a59f5 | 97 | #include "myproposal.h" |
a306f2dd | 98 | #include "authfile.h" |
42f11eb2 | 99 | #include "pathnames.h" |
100 | #include "atomicio.h" | |
101 | #include "canohost.h" | |
102 | #include "auth.h" | |
103 | #include "misc.h" | |
b9a549d7 | 104 | #include "msg.h" |
a5c9ffdb | 105 | #include "dispatch.h" |
e4d7f734 | 106 | #include "channels.h" |
1b34c1b3 | 107 | #include "session.h" |
1853d1ef | 108 | #include "monitor_mm.h" |
109 | #include "monitor.h" | |
110 | #include "monitor_wrap.h" | |
111 | #include "monitor_fdpass.h" | |
28015df4 | 112 | #include "version.h" |
8efc0c15 | 113 | |
114 | #ifdef LIBWRAP | |
115 | #include <tcpd.h> | |
116 | #include <syslog.h> | |
117 | int allow_severity = LOG_INFO; | |
118 | int deny_severity = LOG_WARNING; | |
119 | #endif /* LIBWRAP */ | |
120 | ||
121 | #ifndef O_NOCTTY | |
122 | #define O_NOCTTY 0 | |
123 | #endif | |
124 | ||
b250e837 | 125 | /* Re-exec fds */ |
126 | #define REEXEC_DEVCRYPTO_RESERVED_FD (STDERR_FILENO + 1) | |
127 | #define REEXEC_STARTUP_PIPE_FD (STDERR_FILENO + 2) | |
128 | #define REEXEC_CONFIG_PASS_FD (STDERR_FILENO + 3) | |
129 | #define REEXEC_MIN_FREE_FD (STDERR_FILENO + 4) | |
130 | ||
260d427b | 131 | extern char *__progname; |
260d427b | 132 | |
8efc0c15 | 133 | /* Server configuration options. */ |
134 | ServerOptions options; | |
135 | ||
136 | /* Name of the server configuration file. */ | |
42f11eb2 | 137 | char *config_file_name = _PATH_SERVER_CONFIG_FILE; |
8efc0c15 | 138 | |
5260325f | 139 | /* |
140 | * Debug mode flag. This can be set on the command line. If debug | |
141 | * mode is enabled, extra debugging output will be sent to the system | |
142 | * log, the daemon will not go to background, and will exit after processing | |
143 | * the first connection. | |
144 | */ | |
8efc0c15 | 145 | int debug_flag = 0; |
146 | ||
f87f09aa | 147 | /* Flag indicating that the daemon should only test the configuration and keys. */ |
148 | int test_flag = 0; | |
149 | ||
8efc0c15 | 150 | /* Flag indicating that the daemon is being started from inetd. */ |
151 | int inetd_flag = 0; | |
152 | ||
0b6fbf03 | 153 | /* Flag indicating that sshd should not detach and become a daemon. */ |
154 | int no_daemon_flag = 0; | |
155 | ||
6a17f9c2 | 156 | /* debug goes to stderr unless inetd_flag is set */ |
157 | int log_stderr = 0; | |
158 | ||
8efc0c15 | 159 | /* Saved arguments to main(). */ |
160 | char **saved_argv; | |
4d33e531 | 161 | int saved_argc; |
8efc0c15 | 162 | |
b9a549d7 | 163 | /* re-exec */ |
164 | int rexeced_flag = 0; | |
165 | int rexec_flag = 1; | |
166 | int rexec_argc = 0; | |
167 | char **rexec_argv; | |
168 | ||
aa3378df | 169 | /* |
48e671d5 | 170 | * The sockets that the server is listening; this is used in the SIGHUP |
171 | * signal handler. | |
aa3378df | 172 | */ |
48e671d5 | 173 | #define MAX_LISTEN_SOCKS 16 |
174 | int listen_socks[MAX_LISTEN_SOCKS]; | |
175 | int num_listen_socks = 0; | |
8efc0c15 | 176 | |
aa3378df | 177 | /* |
178 | * the client's version string, passed by sshd2 in compat mode. if != NULL, | |
179 | * sshd will skip the version-number exchange | |
180 | */ | |
5260325f | 181 | char *client_version_string = NULL; |
7368a6c8 | 182 | char *server_version_string = NULL; |
8efc0c15 | 183 | |
7a37c112 | 184 | /* for rekeying XXX fixme */ |
185 | Kex *xxx_kex; | |
186 | ||
aa3378df | 187 | /* |
188 | * Any really sensitive data in the application is contained in this | |
189 | * structure. The idea is that this structure could be locked into memory so | |
190 | * that the pages do not get written into swap. However, there are some | |
191 | * problems. The private key contains BIGNUMs, and we do not (in principle) | |
192 | * have access to the internals of them, and locking just the structure is | |
193 | * not very useful. Currently, memory locking is not implemented. | |
194 | */ | |
5260325f | 195 | struct { |
cb7bd922 | 196 | Key *server_key; /* ephemeral server key */ |
fa08c86b | 197 | Key *ssh1_host_key; /* ssh1 host key */ |
198 | Key **host_keys; /* all private host keys */ | |
199 | int have_ssh1_key; | |
200 | int have_ssh2_key; | |
00be5382 | 201 | u_char ssh1_cookie[SSH_SESSION_KEY_LENGTH]; |
8efc0c15 | 202 | } sensitive_data; |
203 | ||
aa3378df | 204 | /* |
59c97189 | 205 | * Flag indicating whether the RSA server key needs to be regenerated. |
206 | * Is set in the SIGALRM handler and cleared when the key is regenerated. | |
aa3378df | 207 | */ |
7a934d1b | 208 | static volatile sig_atomic_t key_do_regen = 0; |
8efc0c15 | 209 | |
c9130033 | 210 | /* This is set to true when a signal is received. */ |
7a934d1b | 211 | static volatile sig_atomic_t received_sighup = 0; |
212 | static volatile sig_atomic_t received_sigterm = 0; | |
8efc0c15 | 213 | |
7368a6c8 | 214 | /* session identifier, used by RSA-auth */ |
1e3b8b07 | 215 | u_char session_id[16]; |
e7c0f9d5 | 216 | |
a306f2dd | 217 | /* same for ssh2 */ |
1e3b8b07 | 218 | u_char *session_id2 = NULL; |
a27002e5 | 219 | u_int session_id2_len = 0; |
a306f2dd | 220 | |
c345cf9d | 221 | /* record remote hostname or ip */ |
1e3b8b07 | 222 | u_int utmp_len = MAXHOSTNAMELEN; |
c345cf9d | 223 | |
7ace8c3b | 224 | /* options.max_startup sized array of fd ints */ |
225 | int *startup_pipes = NULL; | |
226 | int startup_pipe; /* in child */ | |
227 | ||
1853d1ef | 228 | /* variables used for privilege separation */ |
d231781a | 229 | int use_privsep = -1; |
a9b33b95 | 230 | struct monitor *pmonitor = NULL; |
1853d1ef | 231 | |
2362db19 | 232 | /* global authentication context */ |
233 | Authctxt *the_authctxt = NULL; | |
234 | ||
d231781a | 235 | /* sshd_config buffer */ |
236 | Buffer cfg; | |
237 | ||
be2ca0c9 | 238 | /* message to be displayed after login */ |
239 | Buffer loginmsg; | |
240 | ||
7368a6c8 | 241 | /* Prototypes for various functions defined later in this file. */ |
396c147e | 242 | void destroy_sensitive_data(void); |
1853d1ef | 243 | void demote_sensitive_data(void); |
c8d54615 | 244 | |
396c147e | 245 | static void do_ssh1_kex(void); |
246 | static void do_ssh2_kex(void); | |
94ec8c6b | 247 | |
48e671d5 | 248 | /* |
249 | * Close all listening sockets | |
250 | */ | |
396c147e | 251 | static void |
48e671d5 | 252 | close_listen_socks(void) |
253 | { | |
254 | int i; | |
e424e241 | 255 | |
48e671d5 | 256 | for (i = 0; i < num_listen_socks; i++) |
257 | close(listen_socks[i]); | |
258 | num_listen_socks = -1; | |
259 | } | |
260 | ||
7ace8c3b | 261 | static void |
262 | close_startup_pipes(void) | |
263 | { | |
264 | int i; | |
e424e241 | 265 | |
7ace8c3b | 266 | if (startup_pipes) |
267 | for (i = 0; i < options.max_startups; i++) | |
268 | if (startup_pipes[i] != -1) | |
269 | close(startup_pipes[i]); | |
270 | } | |
271 | ||
5260325f | 272 | /* |
273 | * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP; | |
274 | * the effect is to reread the configuration file (and to regenerate | |
275 | * the server key). | |
276 | */ | |
3efa8ea9 | 277 | |
278 | /*ARGSUSED*/ | |
396c147e | 279 | static void |
5260325f | 280 | sighup_handler(int sig) |
8efc0c15 | 281 | { |
6056eb35 | 282 | int save_errno = errno; |
283 | ||
5260325f | 284 | received_sighup = 1; |
285 | signal(SIGHUP, sighup_handler); | |
6056eb35 | 286 | errno = save_errno; |
8efc0c15 | 287 | } |
288 | ||
5260325f | 289 | /* |
290 | * Called from the main program after receiving SIGHUP. | |
291 | * Restarts the server. | |
292 | */ | |
396c147e | 293 | static void |
5ca51e19 | 294 | sighup_restart(void) |
8efc0c15 | 295 | { |
bbe88b6d | 296 | logit("Received SIGHUP; restarting."); |
48e671d5 | 297 | close_listen_socks(); |
7ace8c3b | 298 | close_startup_pipes(); |
5260325f | 299 | execv(saved_argv[0], saved_argv); |
bbe88b6d | 300 | logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0], |
e424e241 | 301 | strerror(errno)); |
5260325f | 302 | exit(1); |
8efc0c15 | 303 | } |
304 | ||
5260325f | 305 | /* |
306 | * Generic signal handler for terminating signals in the master daemon. | |
5260325f | 307 | */ |
3efa8ea9 | 308 | /*ARGSUSED*/ |
396c147e | 309 | static void |
5260325f | 310 | sigterm_handler(int sig) |
8efc0c15 | 311 | { |
c9130033 | 312 | received_sigterm = sig; |
8efc0c15 | 313 | } |
314 | ||
5260325f | 315 | /* |
316 | * SIGCHLD handler. This is called whenever a child dies. This will then | |
c9130033 | 317 | * reap any zombies left by exited children. |
5260325f | 318 | */ |
3efa8ea9 | 319 | /*ARGSUSED*/ |
396c147e | 320 | static void |
5260325f | 321 | main_sigchld_handler(int sig) |
8efc0c15 | 322 | { |
5260325f | 323 | int save_errno = errno; |
e424e241 | 324 | pid_t pid; |
5260325f | 325 | int status; |
5ad13cd7 | 326 | |
8c38e88b | 327 | while ((pid = waitpid(-1, &status, WNOHANG)) > 0 || |
328 | (pid < 0 && errno == EINTR)) | |
5260325f | 329 | ; |
5ad13cd7 | 330 | |
5260325f | 331 | signal(SIGCHLD, main_sigchld_handler); |
332 | errno = save_errno; | |
8efc0c15 | 333 | } |
334 | ||
5260325f | 335 | /* |
336 | * Signal handler for the alarm after the login grace period has expired. | |
337 | */ | |
3efa8ea9 | 338 | /*ARGSUSED*/ |
396c147e | 339 | static void |
5260325f | 340 | grace_alarm_handler(int sig) |
8efc0c15 | 341 | { |
c9130033 | 342 | /* XXX no idea how fix this signal handler */ |
343 | ||
a9b33b95 | 344 | if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0) |
345 | kill(pmonitor->m_pid, SIGALRM); | |
346 | ||
5260325f | 347 | /* Log error and exit. */ |
26b9a3d2 | 348 | fatal("Timeout before authentication for %s", get_remote_ipaddr()); |
5260325f | 349 | } |
8efc0c15 | 350 | |
5260325f | 351 | /* |
352 | * Signal handler for the key regeneration alarm. Note that this | |
353 | * alarm only occurs in the daemon waiting for connections, and it does not | |
354 | * do anything with the private key or random state before forking. | |
355 | * Thus there should be no concurrency control/asynchronous execution | |
356 | * problems. | |
357 | */ | |
396c147e | 358 | static void |
cb7bd922 | 359 | generate_ephemeral_server_key(void) |
fa08c86b | 360 | { |
7fdc56c5 | 361 | u_int32_t rnd = 0; |
00be5382 | 362 | int i; |
363 | ||
cd332296 | 364 | verbose("Generating %s%d bit RSA key.", |
76ca7b01 | 365 | sensitive_data.server_key ? "new " : "", options.server_key_bits); |
fa08c86b | 366 | if (sensitive_data.server_key != NULL) |
367 | key_free(sensitive_data.server_key); | |
cd332296 | 368 | sensitive_data.server_key = key_generate(KEY_RSA1, |
76ca7b01 | 369 | options.server_key_bits); |
370 | verbose("RSA key generation complete."); | |
00be5382 | 371 | |
372 | for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) { | |
373 | if (i % 4 == 0) | |
7fdc56c5 | 374 | rnd = arc4random(); |
375 | sensitive_data.ssh1_cookie[i] = rnd & 0xff; | |
376 | rnd >>= 8; | |
00be5382 | 377 | } |
378 | arc4random_stir(); | |
fa08c86b | 379 | } |
f546c780 | 380 | |
3efa8ea9 | 381 | /*ARGSUSED*/ |
396c147e | 382 | static void |
5260325f | 383 | key_regeneration_alarm(int sig) |
384 | { | |
385 | int save_errno = errno; | |
e424e241 | 386 | |
59c97189 | 387 | signal(SIGALRM, SIG_DFL); |
5260325f | 388 | errno = save_errno; |
59c97189 | 389 | key_do_regen = 1; |
5260325f | 390 | } |
8efc0c15 | 391 | |
396c147e | 392 | static void |
7368a6c8 | 393 | sshd_exchange_identification(int sock_in, int sock_out) |
394 | { | |
2ceb8101 | 395 | u_int i; |
396 | int mismatch; | |
7368a6c8 | 397 | int remote_major, remote_minor; |
a8be9f80 | 398 | int major, minor; |
7368a6c8 | 399 | char *s; |
400 | char buf[256]; /* Must not be larger than remote_version. */ | |
401 | char remote_version[256]; /* Must be at least as big as buf. */ | |
402 | ||
a8be9f80 | 403 | if ((options.protocol & SSH_PROTO_1) && |
404 | (options.protocol & SSH_PROTO_2)) { | |
405 | major = PROTOCOL_MAJOR_1; | |
406 | minor = 99; | |
407 | } else if (options.protocol & SSH_PROTO_2) { | |
408 | major = PROTOCOL_MAJOR_2; | |
409 | minor = PROTOCOL_MINOR_2; | |
410 | } else { | |
411 | major = PROTOCOL_MAJOR_1; | |
412 | minor = PROTOCOL_MINOR_1; | |
413 | } | |
414 | snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", major, minor, SSH_VERSION); | |
7368a6c8 | 415 | server_version_string = xstrdup(buf); |
416 | ||
7b390973 | 417 | /* Send our protocol version identification. */ |
418 | if (atomicio(vwrite, sock_out, server_version_string, | |
419 | strlen(server_version_string)) | |
420 | != strlen(server_version_string)) { | |
421 | logit("Could not write ident string to %s", get_remote_ipaddr()); | |
2362db19 | 422 | cleanup_exit(255); |
7b390973 | 423 | } |
424 | ||
425 | /* Read other sides version identification. */ | |
426 | memset(buf, 0, sizeof(buf)); | |
427 | for (i = 0; i < sizeof(buf) - 1; i++) { | |
428 | if (atomicio(read, sock_in, &buf[i], 1) != 1) { | |
429 | logit("Did not receive identification string from %s", | |
430 | get_remote_ipaddr()); | |
2362db19 | 431 | cleanup_exit(255); |
7368a6c8 | 432 | } |
7b390973 | 433 | if (buf[i] == '\r') { |
434 | buf[i] = 0; | |
435 | /* Kludge for F-Secure Macintosh < 1.0.2 */ | |
436 | if (i == 12 && | |
437 | strncmp(buf, "SSH-1.5-W1.0", 12) == 0) | |
7368a6c8 | 438 | break; |
7b390973 | 439 | continue; |
440 | } | |
441 | if (buf[i] == '\n') { | |
442 | buf[i] = 0; | |
443 | break; | |
7368a6c8 | 444 | } |
7368a6c8 | 445 | } |
7b390973 | 446 | buf[sizeof(buf) - 1] = 0; |
447 | client_version_string = xstrdup(buf); | |
7368a6c8 | 448 | |
449 | /* | |
450 | * Check that the versions match. In future this might accept | |
451 | * several versions and set appropriate flags to handle them. | |
452 | */ | |
453 | if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n", | |
454 | &remote_major, &remote_minor, remote_version) != 3) { | |
6ae2364d | 455 | s = "Protocol mismatch.\n"; |
dc54438a | 456 | (void) atomicio(vwrite, sock_out, s, strlen(s)); |
7368a6c8 | 457 | close(sock_in); |
458 | close(sock_out); | |
bbe88b6d | 459 | logit("Bad protocol version identification '%.100s' from %s", |
7368a6c8 | 460 | client_version_string, get_remote_ipaddr()); |
2362db19 | 461 | cleanup_exit(255); |
7368a6c8 | 462 | } |
463 | debug("Client protocol version %d.%d; client software version %.100s", | |
184eed6a | 464 | remote_major, remote_minor, remote_version); |
7368a6c8 | 465 | |
e78a59f5 | 466 | compat_datafellows(remote_version); |
467 | ||
9a87e2ac | 468 | if (datafellows & SSH_BUG_PROBE) { |
bbe88b6d | 469 | logit("probed from %s with %s. Don't panic.", |
9a87e2ac | 470 | get_remote_ipaddr(), client_version_string); |
2362db19 | 471 | cleanup_exit(255); |
9a87e2ac | 472 | } |
473 | ||
3a1c54d4 | 474 | if (datafellows & SSH_BUG_SCANNER) { |
bbe88b6d | 475 | logit("scanned from %s with %s. Don't panic.", |
3a1c54d4 | 476 | get_remote_ipaddr(), client_version_string); |
2362db19 | 477 | cleanup_exit(255); |
3a1c54d4 | 478 | } |
479 | ||
a8be9f80 | 480 | mismatch = 0; |
6aacefa7 | 481 | switch (remote_major) { |
7368a6c8 | 482 | case 1: |
a306f2dd | 483 | if (remote_minor == 99) { |
484 | if (options.protocol & SSH_PROTO_2) | |
485 | enable_compat20(); | |
486 | else | |
487 | mismatch = 1; | |
488 | break; | |
489 | } | |
a8be9f80 | 490 | if (!(options.protocol & SSH_PROTO_1)) { |
491 | mismatch = 1; | |
492 | break; | |
493 | } | |
7368a6c8 | 494 | if (remote_minor < 3) { |
089fbbd2 | 495 | packet_disconnect("Your ssh version is too old and " |
7368a6c8 | 496 | "is no longer supported. Please install a newer version."); |
497 | } else if (remote_minor == 3) { | |
498 | /* note that this disables agent-forwarding */ | |
499 | enable_compat13(); | |
500 | } | |
a8be9f80 | 501 | break; |
e78a59f5 | 502 | case 2: |
a8be9f80 | 503 | if (options.protocol & SSH_PROTO_2) { |
e78a59f5 | 504 | enable_compat20(); |
505 | break; | |
506 | } | |
507 | /* FALLTHROUGH */ | |
6ae2364d | 508 | default: |
a8be9f80 | 509 | mismatch = 1; |
510 | break; | |
511 | } | |
512 | chop(server_version_string); | |
a8be9f80 | 513 | debug("Local version string %.200s", server_version_string); |
514 | ||
515 | if (mismatch) { | |
7368a6c8 | 516 | s = "Protocol major versions differ.\n"; |
dc54438a | 517 | (void) atomicio(vwrite, sock_out, s, strlen(s)); |
7368a6c8 | 518 | close(sock_in); |
519 | close(sock_out); | |
bbe88b6d | 520 | logit("Protocol major versions differ for %s: %.200s vs. %.200s", |
a8be9f80 | 521 | get_remote_ipaddr(), |
522 | server_version_string, client_version_string); | |
2362db19 | 523 | cleanup_exit(255); |
7368a6c8 | 524 | } |
a306f2dd | 525 | } |
526 | ||
fa08c86b | 527 | /* Destroy the host and server keys. They will no longer be needed. */ |
a306f2dd | 528 | void |
529 | destroy_sensitive_data(void) | |
530 | { | |
fa08c86b | 531 | int i; |
532 | ||
533 | if (sensitive_data.server_key) { | |
534 | key_free(sensitive_data.server_key); | |
535 | sensitive_data.server_key = NULL; | |
536 | } | |
184eed6a | 537 | for (i = 0; i < options.num_host_key_files; i++) { |
fa08c86b | 538 | if (sensitive_data.host_keys[i]) { |
539 | key_free(sensitive_data.host_keys[i]); | |
540 | sensitive_data.host_keys[i] = NULL; | |
541 | } | |
542 | } | |
543 | sensitive_data.ssh1_host_key = NULL; | |
00be5382 | 544 | memset(sensitive_data.ssh1_cookie, 0, SSH_SESSION_KEY_LENGTH); |
fa08c86b | 545 | } |
fa08c86b | 546 | |
1853d1ef | 547 | /* Demote private to public keys for network child */ |
548 | void | |
549 | demote_sensitive_data(void) | |
550 | { | |
551 | Key *tmp; | |
552 | int i; | |
553 | ||
554 | if (sensitive_data.server_key) { | |
555 | tmp = key_demote(sensitive_data.server_key); | |
556 | key_free(sensitive_data.server_key); | |
557 | sensitive_data.server_key = tmp; | |
558 | } | |
559 | ||
560 | for (i = 0; i < options.num_host_key_files; i++) { | |
561 | if (sensitive_data.host_keys[i]) { | |
562 | tmp = key_demote(sensitive_data.host_keys[i]); | |
563 | key_free(sensitive_data.host_keys[i]); | |
564 | sensitive_data.host_keys[i] = tmp; | |
565 | if (tmp->type == KEY_RSA1) | |
566 | sensitive_data.ssh1_host_key = tmp; | |
567 | } | |
568 | } | |
569 | ||
570 | /* We do not clear ssh1_host key and cookie. XXX - Okay Niels? */ | |
571 | } | |
572 | ||
51aeb639 | 573 | static void |
1853d1ef | 574 | privsep_preauth_child(void) |
575 | { | |
7fdc56c5 | 576 | u_int32_t rnd[256]; |
6ded293b | 577 | gid_t gidset[1]; |
2ea6de2b | 578 | struct passwd *pw; |
e424e241 | 579 | int i; |
1853d1ef | 580 | |
581 | /* Enable challenge-response authentication for privilege separation */ | |
582 | privsep_challenge_enable(); | |
583 | ||
584 | for (i = 0; i < 256; i++) | |
7fdc56c5 | 585 | rnd[i] = arc4random(); |
586 | RAND_seed(rnd, sizeof(rnd)); | |
1853d1ef | 587 | |
588 | /* Demote the private keys to public keys. */ | |
589 | demote_sensitive_data(); | |
590 | ||
2ea6de2b | 591 | if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) |
cdc4fc39 | 592 | fatal("Privilege separation user %s does not exist", |
593 | SSH_PRIVSEP_USER); | |
2ea6de2b | 594 | memset(pw->pw_passwd, 0, strlen(pw->pw_passwd)); |
595 | endpwent(); | |
596 | ||
343288b8 | 597 | /* Change our root directory */ |
1c352e97 | 598 | if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1) |
599 | fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR, | |
600 | strerror(errno)); | |
1853d1ef | 601 | if (chdir("/") == -1) |
edfb66cb | 602 | fatal("chdir(\"/\"): %s", strerror(errno)); |
762715ce | 603 | |
1853d1ef | 604 | /* Drop our privileges */ |
2ea6de2b | 605 | debug3("privsep user:group %u:%u", (u_int)pw->pw_uid, |
606 | (u_int)pw->pw_gid); | |
87809a1f | 607 | #if 0 |
6ff58a4b | 608 | /* XXX not ready, too heavy after chroot */ |
2ea6de2b | 609 | do_setusercontext(pw); |
87809a1f | 610 | #else |
611 | gidset[0] = pw->pw_gid; | |
87809a1f | 612 | if (setgroups(1, gidset) < 0) |
613 | fatal("setgroups: %.100s", strerror(errno)); | |
614 | permanently_set_uid(pw); | |
615 | #endif | |
1853d1ef | 616 | } |
617 | ||
2362db19 | 618 | static int |
619 | privsep_preauth(Authctxt *authctxt) | |
1853d1ef | 620 | { |
1853d1ef | 621 | int status; |
324bf712 | 622 | pid_t pid; |
1853d1ef | 623 | |
324bf712 | 624 | /* Set up unprivileged child process to deal with network data */ |
b5a28cbc | 625 | pmonitor = monitor_init(); |
324bf712 | 626 | /* Store a pointer to the kex for later rekeying */ |
b5a28cbc | 627 | pmonitor->m_pkex = &xxx_kex; |
324bf712 | 628 | |
629 | pid = fork(); | |
630 | if (pid == -1) { | |
631 | fatal("fork of unprivileged child failed"); | |
632 | } else if (pid != 0) { | |
c457707e | 633 | debug2("Network child is on pid %ld", (long)pid); |
324bf712 | 634 | |
b5a28cbc | 635 | close(pmonitor->m_recvfd); |
a9b33b95 | 636 | pmonitor->m_pid = pid; |
2362db19 | 637 | monitor_child_preauth(authctxt, pmonitor); |
b5a28cbc | 638 | close(pmonitor->m_sendfd); |
324bf712 | 639 | |
640 | /* Sync memory */ | |
b5a28cbc | 641 | monitor_sync(pmonitor); |
324bf712 | 642 | |
643 | /* Wait for the child's exit status */ | |
8c38e88b | 644 | while (waitpid(pid, &status, 0) < 0) |
645 | if (errno != EINTR) | |
646 | break; | |
2362db19 | 647 | return (1); |
324bf712 | 648 | } else { |
649 | /* child */ | |
650 | ||
b5a28cbc | 651 | close(pmonitor->m_sendfd); |
324bf712 | 652 | |
653 | /* Demote the child */ | |
654 | if (getuid() == 0 || geteuid() == 0) | |
655 | privsep_preauth_child(); | |
47c36e5b | 656 | setproctitle("%s", "[net]"); |
324bf712 | 657 | } |
2362db19 | 658 | return (0); |
324bf712 | 659 | } |
660 | ||
661 | static void | |
662 | privsep_postauth(Authctxt *authctxt) | |
663 | { | |
94d8258b | 664 | #ifdef DISABLE_FD_PASSING |
d170feb1 | 665 | if (1) { |
666 | #else | |
1853d1ef | 667 | if (authctxt->pw->pw_uid == 0 || options.use_login) { |
d170feb1 | 668 | #endif |
1853d1ef | 669 | /* File descriptor passing is broken or root login */ |
1853d1ef | 670 | use_privsep = 0; |
ae25711b | 671 | goto skip; |
1853d1ef | 672 | } |
762715ce | 673 | |
1853d1ef | 674 | /* New socket pair */ |
b5a28cbc | 675 | monitor_reinit(pmonitor); |
1853d1ef | 676 | |
b5a28cbc | 677 | pmonitor->m_pid = fork(); |
678 | if (pmonitor->m_pid == -1) | |
1853d1ef | 679 | fatal("fork of unprivileged child failed"); |
b5a28cbc | 680 | else if (pmonitor->m_pid != 0) { |
c457707e | 681 | debug2("User child is on pid %ld", (long)pmonitor->m_pid); |
b5a28cbc | 682 | close(pmonitor->m_recvfd); |
f143ed33 | 683 | buffer_clear(&loginmsg); |
b5a28cbc | 684 | monitor_child_postauth(pmonitor); |
1853d1ef | 685 | |
686 | /* NEVERREACHED */ | |
687 | exit(0); | |
688 | } | |
689 | ||
b5a28cbc | 690 | close(pmonitor->m_sendfd); |
1853d1ef | 691 | |
692 | /* Demote the private keys to public keys. */ | |
693 | demote_sensitive_data(); | |
694 | ||
695 | /* Drop privileges */ | |
696 | do_setusercontext(authctxt->pw); | |
697 | ||
ae25711b | 698 | skip: |
1853d1ef | 699 | /* It is safe now to apply the key state */ |
b5a28cbc | 700 | monitor_apply_keystate(pmonitor); |
07200973 | 701 | |
702 | /* | |
703 | * Tell the packet layer that authentication was successful, since | |
704 | * this information is not part of the key state. | |
705 | */ | |
706 | packet_set_authenticated(); | |
1853d1ef | 707 | } |
708 | ||
396c147e | 709 | static char * |
fa08c86b | 710 | list_hostkey_types(void) |
711 | { | |
3469eac4 | 712 | Buffer b; |
b6c7b7b7 | 713 | const char *p; |
714 | char *ret; | |
fa08c86b | 715 | int i; |
3469eac4 | 716 | |
717 | buffer_init(&b); | |
184eed6a | 718 | for (i = 0; i < options.num_host_key_files; i++) { |
fa08c86b | 719 | Key *key = sensitive_data.host_keys[i]; |
720 | if (key == NULL) | |
721 | continue; | |
6aacefa7 | 722 | switch (key->type) { |
fa08c86b | 723 | case KEY_RSA: |
724 | case KEY_DSA: | |
3469eac4 | 725 | if (buffer_len(&b) > 0) |
726 | buffer_append(&b, ",", 1); | |
727 | p = key_ssh_name(key); | |
728 | buffer_append(&b, p, strlen(p)); | |
fa08c86b | 729 | break; |
730 | } | |
731 | } | |
3469eac4 | 732 | buffer_append(&b, "\0", 1); |
b6c7b7b7 | 733 | ret = xstrdup(buffer_ptr(&b)); |
3469eac4 | 734 | buffer_free(&b); |
b6c7b7b7 | 735 | debug("list_hostkey_types: %s", ret); |
736 | return ret; | |
fa08c86b | 737 | } |
738 | ||
1853d1ef | 739 | Key * |
fa08c86b | 740 | get_hostkey_by_type(int type) |
741 | { | |
742 | int i; | |
e424e241 | 743 | |
184eed6a | 744 | for (i = 0; i < options.num_host_key_files; i++) { |
fa08c86b | 745 | Key *key = sensitive_data.host_keys[i]; |
746 | if (key != NULL && key->type == type) | |
747 | return key; | |
748 | } | |
749 | return NULL; | |
7368a6c8 | 750 | } |
751 | ||
1853d1ef | 752 | Key * |
753 | get_hostkey_by_index(int ind) | |
754 | { | |
755 | if (ind < 0 || ind >= options.num_host_key_files) | |
756 | return (NULL); | |
757 | return (sensitive_data.host_keys[ind]); | |
758 | } | |
759 | ||
760 | int | |
761 | get_hostkey_index(Key *key) | |
762 | { | |
763 | int i; | |
e424e241 | 764 | |
1853d1ef | 765 | for (i = 0; i < options.num_host_key_files; i++) { |
766 | if (key == sensitive_data.host_keys[i]) | |
767 | return (i); | |
768 | } | |
769 | return (-1); | |
770 | } | |
771 | ||
c345cf9d | 772 | /* |
773 | * returns 1 if connection should be dropped, 0 otherwise. | |
774 | * dropping starts at connection #max_startups_begin with a probability | |
775 | * of (max_startups_rate/100). the probability increases linearly until | |
776 | * all connections are dropped for startups > max_startups | |
777 | */ | |
396c147e | 778 | static int |
c345cf9d | 779 | drop_connection(int startups) |
780 | { | |
1c5eab6f | 781 | int p, r; |
c345cf9d | 782 | |
783 | if (startups < options.max_startups_begin) | |
784 | return 0; | |
785 | if (startups >= options.max_startups) | |
786 | return 1; | |
787 | if (options.max_startups_rate == 100) | |
788 | return 1; | |
789 | ||
790 | p = 100 - options.max_startups_rate; | |
791 | p *= startups - options.max_startups_begin; | |
1c5eab6f | 792 | p /= options.max_startups - options.max_startups_begin; |
c345cf9d | 793 | p += options.max_startups_rate; |
1c5eab6f | 794 | r = arc4random() % 100; |
c345cf9d | 795 | |
e9aec1d4 | 796 | debug("drop_connection: p %d, r %d", p, r); |
c345cf9d | 797 | return (r < p) ? 1 : 0; |
798 | } | |
799 | ||
2717fa0f | 800 | static void |
801 | usage(void) | |
802 | { | |
85ac7a84 | 803 | fprintf(stderr, "%s, %s\n", |
4526e8c2 | 804 | SSH_RELEASE, SSLeay_version(SSLEAY_VERSION)); |
65edde94 | 805 | fprintf(stderr, |
806 | "usage: sshd [-46Ddeiqt] [-b bits] [-f config_file] [-g login_grace_time]\n" | |
807 | " [-h host_key_file] [-k key_gen_time] [-o option] [-p port] [-u len]\n" | |
808 | ); | |
2717fa0f | 809 | exit(1); |
810 | } | |
811 | ||
b9a549d7 | 812 | static void |
813 | send_rexec_state(int fd, Buffer *conf) | |
814 | { | |
815 | Buffer m; | |
816 | ||
817 | debug3("%s: entering fd = %d config len %d", __func__, fd, | |
818 | buffer_len(conf)); | |
819 | ||
820 | /* | |
821 | * Protocol from reexec master to child: | |
822 | * string configuration | |
823 | * u_int ephemeral_key_follows | |
824 | * bignum e (only if ephemeral_key_follows == 1) | |
825 | * bignum n " | |
826 | * bignum d " | |
827 | * bignum iqmp " | |
828 | * bignum p " | |
829 | * bignum q " | |
72f02ae7 | 830 | * string rngseed (only if OpenSSL is not self-seeded) |
b9a549d7 | 831 | */ |
832 | buffer_init(&m); | |
833 | buffer_put_cstring(&m, buffer_ptr(conf)); | |
834 | ||
f2107e97 | 835 | if (sensitive_data.server_key != NULL && |
b9a549d7 | 836 | sensitive_data.server_key->type == KEY_RSA1) { |
837 | buffer_put_int(&m, 1); | |
838 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->e); | |
839 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->n); | |
840 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->d); | |
841 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->iqmp); | |
842 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->p); | |
843 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->q); | |
844 | } else | |
845 | buffer_put_int(&m, 0); | |
846 | ||
72f02ae7 | 847 | #ifndef OPENSSL_PRNG_ONLY |
848 | rexec_send_rng_seed(&m); | |
849 | #endif | |
850 | ||
b9a549d7 | 851 | if (ssh_msg_send(fd, 0, &m) == -1) |
852 | fatal("%s: ssh_msg_send failed", __func__); | |
853 | ||
854 | buffer_free(&m); | |
855 | ||
856 | debug3("%s: done", __func__); | |
857 | } | |
858 | ||
859 | static void | |
860 | recv_rexec_state(int fd, Buffer *conf) | |
861 | { | |
862 | Buffer m; | |
863 | char *cp; | |
864 | u_int len; | |
865 | ||
866 | debug3("%s: entering fd = %d", __func__, fd); | |
867 | ||
868 | buffer_init(&m); | |
869 | ||
870 | if (ssh_msg_recv(fd, &m) == -1) | |
871 | fatal("%s: ssh_msg_recv failed", __func__); | |
872 | if (buffer_get_char(&m) != 0) | |
873 | fatal("%s: rexec version mismatch", __func__); | |
874 | ||
875 | cp = buffer_get_string(&m, &len); | |
876 | if (conf != NULL) | |
877 | buffer_append(conf, cp, len + 1); | |
878 | xfree(cp); | |
879 | ||
880 | if (buffer_get_int(&m)) { | |
881 | if (sensitive_data.server_key != NULL) | |
882 | key_free(sensitive_data.server_key); | |
883 | sensitive_data.server_key = key_new_private(KEY_RSA1); | |
884 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->e); | |
885 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->n); | |
886 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->d); | |
887 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->iqmp); | |
888 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->p); | |
889 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->q); | |
890 | rsa_generate_additional_parameters( | |
891 | sensitive_data.server_key->rsa); | |
892 | } | |
72f02ae7 | 893 | |
894 | #ifndef OPENSSL_PRNG_ONLY | |
895 | rexec_recv_rng_seed(&m); | |
896 | #endif | |
897 | ||
b9a549d7 | 898 | buffer_free(&m); |
899 | ||
900 | debug3("%s: done", __func__); | |
901 | } | |
902 | ||
5260325f | 903 | /* |
904 | * Main program for the daemon. | |
905 | */ | |
8efc0c15 | 906 | int |
907 | main(int ac, char **av) | |
908 | { | |
5260325f | 909 | extern char *optarg; |
910 | extern int optind; | |
52e3daed | 911 | int opt, j, i, on = 1; |
83529a6b | 912 | int sock_in = -1, sock_out = -1, newsock = -1; |
9da5c3c9 | 913 | pid_t pid; |
48e671d5 | 914 | socklen_t fromlen; |
48e671d5 | 915 | fd_set *fdset; |
916 | struct sockaddr_storage from; | |
5260325f | 917 | const char *remote_ip; |
918 | int remote_port; | |
5260325f | 919 | FILE *f; |
48e671d5 | 920 | struct addrinfo *ai; |
921 | char ntop[NI_MAXHOST], strport[NI_MAXSERV]; | |
c5894280 | 922 | char *line; |
48e671d5 | 923 | int listen_sock, maxfd; |
9216f89c | 924 | int startup_p[2] = { -1 , -1 }, config_s[2] = { -1 , -1 }; |
089fbbd2 | 925 | int startups = 0; |
aeaa3d9e | 926 | Key *key; |
2362db19 | 927 | Authctxt *authctxt; |
59c97189 | 928 | int ret, key_used = 0; |
5260325f | 929 | |
6e879cb4 | 930 | #ifdef HAVE_SECUREWARE |
931 | (void)set_auth_parameters(ac, av); | |
932 | #endif | |
fda04d7d | 933 | __progname = ssh_get_progname(av[0]); |
264dce47 | 934 | init_rng(); |
935 | ||
d0104542 | 936 | /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */ |
4d33e531 | 937 | saved_argc = ac; |
7706b4c7 | 938 | rexec_argc = ac; |
01d35895 | 939 | saved_argv = xcalloc(ac + 1, sizeof(*saved_argv)); |
d0104542 | 940 | for (i = 0; i < ac; i++) |
941 | saved_argv[i] = xstrdup(av[i]); | |
f420d2ba | 942 | saved_argv[i] = NULL; |
d0104542 | 943 | |
944 | #ifndef HAVE_SETPROCTITLE | |
945 | /* Prepare for later setproctitle emulation */ | |
946 | compat_init_setproctitle(ac, av); | |
416c732d | 947 | av = saved_argv; |
d0104542 | 948 | #endif |
5260325f | 949 | |
a4c0faa2 | 950 | if (geteuid() == 0 && setgroups(0, NULL) == -1) |
951 | debug("setgroups(): %.200s", strerror(errno)); | |
952 | ||
fd6168c1 | 953 | /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ |
954 | sanitise_stdfd(); | |
955 | ||
5260325f | 956 | /* Initialize configuration options to their default values. */ |
957 | initialize_server_options(&options); | |
958 | ||
959 | /* Parse command-line arguments. */ | |
b9a549d7 | 960 | while ((opt = getopt(ac, av, "f:p:b:k:h:g:u:o:dDeiqrtQR46")) != -1) { |
5260325f | 961 | switch (opt) { |
48e671d5 | 962 | case '4': |
31b41ceb | 963 | options.address_family = AF_INET; |
48e671d5 | 964 | break; |
965 | case '6': | |
31b41ceb | 966 | options.address_family = AF_INET6; |
48e671d5 | 967 | break; |
5260325f | 968 | case 'f': |
969 | config_file_name = optarg; | |
970 | break; | |
971 | case 'd': | |
e053cd2c | 972 | if (debug_flag == 0) { |
bcbf86ec | 973 | debug_flag = 1; |
974 | options.log_level = SYSLOG_LEVEL_DEBUG1; | |
e053cd2c | 975 | } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) |
bcbf86ec | 976 | options.log_level++; |
5260325f | 977 | break; |
0b6fbf03 | 978 | case 'D': |
979 | no_daemon_flag = 1; | |
980 | break; | |
ff14faf1 | 981 | case 'e': |
982 | log_stderr = 1; | |
983 | break; | |
5260325f | 984 | case 'i': |
985 | inetd_flag = 1; | |
986 | break; | |
b9a549d7 | 987 | case 'r': |
988 | rexec_flag = 0; | |
989 | break; | |
990 | case 'R': | |
991 | rexeced_flag = 1; | |
992 | inetd_flag = 1; | |
993 | break; | |
5260325f | 994 | case 'Q': |
9bd5b720 | 995 | /* ignored */ |
5260325f | 996 | break; |
997 | case 'q': | |
998 | options.log_level = SYSLOG_LEVEL_QUIET; | |
999 | break; | |
1000 | case 'b': | |
3efa8ea9 | 1001 | options.server_key_bits = (int)strtonum(optarg, 256, |
1002 | 32768, NULL); | |
5260325f | 1003 | break; |
1004 | case 'p': | |
48e671d5 | 1005 | options.ports_from_cmdline = 1; |
bcbf86ec | 1006 | if (options.num_ports >= MAX_PORTS) { |
1007 | fprintf(stderr, "too many ports.\n"); | |
1008 | exit(1); | |
1009 | } | |
2d2a2c65 | 1010 | options.ports[options.num_ports++] = a2port(optarg); |
1011 | if (options.ports[options.num_ports-1] == 0) { | |
1012 | fprintf(stderr, "Bad port number.\n"); | |
1013 | exit(1); | |
1014 | } | |
5260325f | 1015 | break; |
1016 | case 'g': | |
e2b1fb42 | 1017 | if ((options.login_grace_time = convtime(optarg)) == -1) { |
1018 | fprintf(stderr, "Invalid login grace time.\n"); | |
1019 | exit(1); | |
1020 | } | |
5260325f | 1021 | break; |
1022 | case 'k': | |
e2b1fb42 | 1023 | if ((options.key_regeneration_time = convtime(optarg)) == -1) { |
1024 | fprintf(stderr, "Invalid key regeneration interval.\n"); | |
1025 | exit(1); | |
1026 | } | |
5260325f | 1027 | break; |
1028 | case 'h': | |
fa08c86b | 1029 | if (options.num_host_key_files >= MAX_HOSTKEYS) { |
1030 | fprintf(stderr, "too many host keys.\n"); | |
1031 | exit(1); | |
1032 | } | |
1033 | options.host_key_files[options.num_host_key_files++] = optarg; | |
5260325f | 1034 | break; |
f87f09aa | 1035 | case 't': |
1036 | test_flag = 1; | |
1037 | break; | |
c345cf9d | 1038 | case 'u': |
3efa8ea9 | 1039 | utmp_len = (u_int)strtonum(optarg, 0, MAXHOSTNAMELEN+1, NULL); |
67f04db1 | 1040 | if (utmp_len > MAXHOSTNAMELEN) { |
1041 | fprintf(stderr, "Invalid utmp length.\n"); | |
1042 | exit(1); | |
1043 | } | |
c345cf9d | 1044 | break; |
2717fa0f | 1045 | case 'o': |
c5894280 | 1046 | line = xstrdup(optarg); |
1047 | if (process_server_config_line(&options, line, | |
d231781a | 1048 | "command-line", 0, NULL, NULL, NULL, NULL) != 0) |
184eed6a | 1049 | exit(1); |
c5894280 | 1050 | xfree(line); |
2717fa0f | 1051 | break; |
5260325f | 1052 | case '?': |
1053 | default: | |
2717fa0f | 1054 | usage(); |
1055 | break; | |
5260325f | 1056 | } |
1057 | } | |
b9a549d7 | 1058 | if (rexeced_flag || inetd_flag) |
1059 | rexec_flag = 0; | |
1060 | if (rexec_flag && (av[0] == NULL || *av[0] != '/')) | |
1061 | fatal("sshd re-exec requires execution with an absolute path"); | |
1062 | if (rexeced_flag) | |
b250e837 | 1063 | closefrom(REEXEC_MIN_FREE_FD); |
1064 | else | |
1065 | closefrom(REEXEC_DEVCRYPTO_RESERVED_FD); | |
b9a549d7 | 1066 | |
1a92bd7e | 1067 | SSLeay_add_all_algorithms(); |
5260325f | 1068 | |
48e671d5 | 1069 | /* |
1070 | * Force logging to stderr until we have loaded the private host | |
1071 | * key (unless started from inetd) | |
1072 | */ | |
1fe6a48f | 1073 | log_init(__progname, |
980c9344 | 1074 | options.log_level == SYSLOG_LEVEL_NOT_SET ? |
1075 | SYSLOG_LEVEL_INFO : options.log_level, | |
1076 | options.log_facility == SYSLOG_FACILITY_NOT_SET ? | |
1077 | SYSLOG_FACILITY_AUTH : options.log_facility, | |
51efad8c | 1078 | log_stderr || !inetd_flag); |
48e671d5 | 1079 | |
351f44a0 | 1080 | /* |
1081 | * Unset KRB5CCNAME, otherwise the user's session may inherit it from | |
1082 | * root's environment | |
d1cf9a87 | 1083 | */ |
3bfd27d5 | 1084 | if (getenv("KRB5CCNAME") != NULL) |
1085 | unsetenv("KRB5CCNAME"); | |
1086 | ||
ef51930f | 1087 | #ifdef _UNICOS |
e5ba4718 | 1088 | /* Cray can define user privs drop all privs now! |
1a23ac2c | 1089 | * Not needed on PRIV_SU systems! |
1090 | */ | |
1091 | drop_cray_privs(); | |
1092 | #endif | |
1093 | ||
b9a549d7 | 1094 | sensitive_data.server_key = NULL; |
1095 | sensitive_data.ssh1_host_key = NULL; | |
1096 | sensitive_data.have_ssh1_key = 0; | |
1097 | sensitive_data.have_ssh2_key = 0; | |
1098 | ||
1099 | /* Fetch our configuration */ | |
1100 | buffer_init(&cfg); | |
1101 | if (rexeced_flag) | |
b250e837 | 1102 | recv_rexec_state(REEXEC_CONFIG_PASS_FD, &cfg); |
b9a549d7 | 1103 | else |
1104 | load_server_config(config_file_name, &cfg); | |
1105 | ||
d231781a | 1106 | parse_server_config(&options, rexeced_flag ? "rexec" : config_file_name, |
1107 | &cfg, NULL, NULL, NULL); | |
5260325f | 1108 | |
72f02ae7 | 1109 | seed_rng(); |
1110 | ||
5260325f | 1111 | /* Fill in default values for those options not explicitly set. */ |
1112 | fill_default_server_options(&options); | |
1113 | ||
31b41ceb | 1114 | /* set default channel AF */ |
1115 | channel_set_af(options.address_family); | |
1116 | ||
5260325f | 1117 | /* Check that there are no remaining arguments. */ |
1118 | if (optind < ac) { | |
1119 | fprintf(stderr, "Extra argument %s.\n", av[optind]); | |
1120 | exit(1); | |
8efc0c15 | 1121 | } |
5260325f | 1122 | |
4526e8c2 | 1123 | debug("sshd version %.100s", SSH_RELEASE); |
5260325f | 1124 | |
fa08c86b | 1125 | /* load private host keys */ |
52e3daed | 1126 | sensitive_data.host_keys = xcalloc(options.num_host_key_files, |
343288b8 | 1127 | sizeof(Key *)); |
184eed6a | 1128 | for (i = 0; i < options.num_host_key_files; i++) |
1e3b8b07 | 1129 | sensitive_data.host_keys[i] = NULL; |
a306f2dd | 1130 | |
184eed6a | 1131 | for (i = 0; i < options.num_host_key_files; i++) { |
aeaa3d9e | 1132 | key = key_load_private(options.host_key_files[i], "", NULL); |
1133 | sensitive_data.host_keys[i] = key; | |
fa08c86b | 1134 | if (key == NULL) { |
58cfa257 | 1135 | error("Could not load host key: %s", |
1136 | options.host_key_files[i]); | |
aeaa3d9e | 1137 | sensitive_data.host_keys[i] = NULL; |
fa08c86b | 1138 | continue; |
a306f2dd | 1139 | } |
6aacefa7 | 1140 | switch (key->type) { |
fa08c86b | 1141 | case KEY_RSA1: |
1142 | sensitive_data.ssh1_host_key = key; | |
1143 | sensitive_data.have_ssh1_key = 1; | |
1144 | break; | |
1145 | case KEY_RSA: | |
1146 | case KEY_DSA: | |
1147 | sensitive_data.have_ssh2_key = 1; | |
1148 | break; | |
a306f2dd | 1149 | } |
aeaa3d9e | 1150 | debug("private host key: #%d type %d %s", i, key->type, |
1151 | key_type(key)); | |
fa08c86b | 1152 | } |
1153 | if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) { | |
bbe88b6d | 1154 | logit("Disabling protocol version 1. Could not load host key"); |
fa08c86b | 1155 | options.protocol &= ~SSH_PROTO_1; |
1156 | } | |
1157 | if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) { | |
bbe88b6d | 1158 | logit("Disabling protocol version 2. Could not load host key"); |
fa08c86b | 1159 | options.protocol &= ~SSH_PROTO_2; |
a306f2dd | 1160 | } |
6a416424 | 1161 | if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) { |
bbe88b6d | 1162 | logit("sshd: no hostkeys available -- exiting."); |
5260325f | 1163 | exit(1); |
1164 | } | |
5260325f | 1165 | |
a306f2dd | 1166 | /* Check certain values for sanity. */ |
1167 | if (options.protocol & SSH_PROTO_1) { | |
1168 | if (options.server_key_bits < 512 || | |
1169 | options.server_key_bits > 32768) { | |
1170 | fprintf(stderr, "Bad server key size.\n"); | |
1171 | exit(1); | |
1172 | } | |
1173 | /* | |
1174 | * Check that server and host key lengths differ sufficiently. This | |
1175 | * is necessary to make double encryption work with rsaref. Oh, I | |
1176 | * hate software patents. I dont know if this can go? Niels | |
1177 | */ | |
1178 | if (options.server_key_bits > | |
e424e241 | 1179 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) - |
1180 | SSH_KEY_BITS_RESERVED && options.server_key_bits < | |
1181 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + | |
1182 | SSH_KEY_BITS_RESERVED) { | |
a306f2dd | 1183 | options.server_key_bits = |
e424e241 | 1184 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + |
1185 | SSH_KEY_BITS_RESERVED; | |
a306f2dd | 1186 | debug("Forcing server key to %d bits to make it differ from host key.", |
1187 | options.server_key_bits); | |
1188 | } | |
1189 | } | |
1190 | ||
3cc54fbb | 1191 | if (use_privsep) { |
3cc54fbb | 1192 | struct stat st; |
1193 | ||
3efa8ea9 | 1194 | if (getpwnam(SSH_PRIVSEP_USER) == NULL) |
3cc54fbb | 1195 | fatal("Privilege separation user %s does not exist", |
1196 | SSH_PRIVSEP_USER); | |
1197 | if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) || | |
1198 | (S_ISDIR(st.st_mode) == 0)) | |
1199 | fatal("Missing privilege separation directory: %s", | |
1200 | _PATH_PRIVSEP_CHROOT_DIR); | |
b9b82dab | 1201 | |
1202 | #ifdef HAVE_CYGWIN | |
1203 | if (check_ntsec(_PATH_PRIVSEP_CHROOT_DIR) && | |
1204 | (st.st_uid != getuid () || | |
1205 | (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)) | |
1206 | #else | |
a56313d7 | 1207 | if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0) |
b9b82dab | 1208 | #endif |
5f021474 | 1209 | fatal("%s must be owned by root and not group or " |
1210 | "world-writable.", _PATH_PRIVSEP_CHROOT_DIR); | |
3cc54fbb | 1211 | } |
1212 | ||
f87f09aa | 1213 | /* Configuration looks good, so exit if in test mode. */ |
1214 | if (test_flag) | |
1215 | exit(0); | |
1216 | ||
018a5ea3 | 1217 | /* |
1218 | * Clear out any supplemental groups we may have inherited. This | |
1219 | * prevents inadvertent creation of files with bad modes (in the | |
aff51935 | 1220 | * portable version at least, it's certainly possible for PAM |
1221 | * to create a file, and we can't control the code in every | |
018a5ea3 | 1222 | * module which might be used). |
1223 | */ | |
1224 | if (setgroups(0, NULL) < 0) | |
1225 | debug("setgroups() failed: %.200s", strerror(errno)); | |
1226 | ||
b9a549d7 | 1227 | if (rexec_flag) { |
52e3daed | 1228 | rexec_argv = xcalloc(rexec_argc + 2, sizeof(char *)); |
b9a549d7 | 1229 | for (i = 0; i < rexec_argc; i++) { |
1230 | debug("rexec_argv[%d]='%s'", i, saved_argv[i]); | |
1231 | rexec_argv[i] = saved_argv[i]; | |
1232 | } | |
1233 | rexec_argv[rexec_argc] = "-R"; | |
1234 | rexec_argv[rexec_argc + 1] = NULL; | |
1235 | } | |
1236 | ||
a306f2dd | 1237 | /* Initialize the log (it is reinitialized below in case we forked). */ |
25c31d49 | 1238 | if (debug_flag && (!inetd_flag || rexeced_flag)) |
5260325f | 1239 | log_stderr = 1; |
1fe6a48f | 1240 | log_init(__progname, options.log_level, options.log_facility, log_stderr); |
5260325f | 1241 | |
a306f2dd | 1242 | /* |
1243 | * If not in debugging mode, and not started from inetd, disconnect | |
1244 | * from the controlling terminal, and fork. The original process | |
1245 | * exits. | |
1246 | */ | |
0b6fbf03 | 1247 | if (!(debug_flag || inetd_flag || no_daemon_flag)) { |
8efc0c15 | 1248 | #ifdef TIOCNOTTY |
5260325f | 1249 | int fd; |
8efc0c15 | 1250 | #endif /* TIOCNOTTY */ |
5260325f | 1251 | if (daemon(0, 0) < 0) |
1252 | fatal("daemon() failed: %.200s", strerror(errno)); | |
1253 | ||
1254 | /* Disconnect from the controlling tty. */ | |
8efc0c15 | 1255 | #ifdef TIOCNOTTY |
5ca51e19 | 1256 | fd = open(_PATH_TTY, O_RDWR | O_NOCTTY); |
5260325f | 1257 | if (fd >= 0) { |
1258 | (void) ioctl(fd, TIOCNOTTY, NULL); | |
1259 | close(fd); | |
1260 | } | |
8efc0c15 | 1261 | #endif /* TIOCNOTTY */ |
8efc0c15 | 1262 | } |
5260325f | 1263 | /* Reinitialize the log (because of the fork above). */ |
1fe6a48f | 1264 | log_init(__progname, options.log_level, options.log_facility, log_stderr); |
5260325f | 1265 | |
5260325f | 1266 | /* Initialize the random number generator. */ |
1267 | arc4random_stir(); | |
1268 | ||
1269 | /* Chdir to the root directory so that the current disk can be | |
1270 | unmounted if desired. */ | |
1271 | chdir("/"); | |
184eed6a | 1272 | |
1d3c30db | 1273 | /* ignore SIGPIPE */ |
1274 | signal(SIGPIPE, SIG_IGN); | |
5260325f | 1275 | |
5260325f | 1276 | /* Start listening for a socket, unless started from inetd. */ |
1277 | if (inetd_flag) { | |
b9a549d7 | 1278 | int fd; |
1279 | ||
4c8722d9 | 1280 | startup_pipe = -1; |
b9a549d7 | 1281 | if (rexeced_flag) { |
b250e837 | 1282 | close(REEXEC_CONFIG_PASS_FD); |
b9a549d7 | 1283 | sock_in = sock_out = dup(STDIN_FILENO); |
1284 | if (!debug_flag) { | |
b250e837 | 1285 | startup_pipe = dup(REEXEC_STARTUP_PIPE_FD); |
1286 | close(REEXEC_STARTUP_PIPE_FD); | |
b9a549d7 | 1287 | } |
1288 | } else { | |
1289 | sock_in = dup(STDIN_FILENO); | |
1290 | sock_out = dup(STDOUT_FILENO); | |
1291 | } | |
a306f2dd | 1292 | /* |
1293 | * We intentionally do not close the descriptors 0, 1, and 2 | |
b9a549d7 | 1294 | * as our code for setting the descriptors won't work if |
a306f2dd | 1295 | * ttyfd happens to be one of those. |
1296 | */ | |
b9a549d7 | 1297 | if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { |
1298 | dup2(fd, STDIN_FILENO); | |
1299 | dup2(fd, STDOUT_FILENO); | |
1300 | if (fd > STDOUT_FILENO) | |
1301 | close(fd); | |
1302 | } | |
5260325f | 1303 | debug("inetd sockets after dupping: %d, %d", sock_in, sock_out); |
b9a549d7 | 1304 | if ((options.protocol & SSH_PROTO_1) && |
1305 | sensitive_data.server_key == NULL) | |
cb7bd922 | 1306 | generate_ephemeral_server_key(); |
5260325f | 1307 | } else { |
48e671d5 | 1308 | for (ai = options.listen_addrs; ai; ai = ai->ai_next) { |
1309 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) | |
1310 | continue; | |
1311 | if (num_listen_socks >= MAX_LISTEN_SOCKS) | |
1312 | fatal("Too many listen sockets. " | |
1313 | "Enlarge MAX_LISTEN_SOCKS"); | |
945a9853 | 1314 | if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen, |
48e671d5 | 1315 | ntop, sizeof(ntop), strport, sizeof(strport), |
945a9853 | 1316 | NI_NUMERICHOST|NI_NUMERICSERV)) != 0) { |
1317 | error("getnameinfo failed: %.100s", | |
1318 | (ret != EAI_SYSTEM) ? gai_strerror(ret) : | |
1319 | strerror(errno)); | |
48e671d5 | 1320 | continue; |
1321 | } | |
1322 | /* Create socket for listening. */ | |
3e131a6d | 1323 | listen_sock = socket(ai->ai_family, ai->ai_socktype, |
1324 | ai->ai_protocol); | |
48e671d5 | 1325 | if (listen_sock < 0) { |
1326 | /* kernel may not support ipv6 */ | |
1327 | verbose("socket: %.100s", strerror(errno)); | |
1328 | continue; | |
1329 | } | |
170694d7 | 1330 | if (set_nonblock(listen_sock) == -1) { |
a666e3b1 | 1331 | close(listen_sock); |
1332 | continue; | |
1333 | } | |
48e671d5 | 1334 | /* |
facfd613 | 1335 | * Set socket options. |
1336 | * Allow local port reuse in TIME_WAIT. | |
48e671d5 | 1337 | */ |
facfd613 | 1338 | if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR, |
1339 | &on, sizeof(on)) == -1) | |
1340 | error("setsockopt SO_REUSEADDR: %s", strerror(errno)); | |
48e671d5 | 1341 | |
1342 | debug("Bind to port %s on %s.", strport, ntop); | |
1343 | ||
1344 | /* Bind the socket to the desired port. */ | |
32ced054 | 1345 | if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) { |
1346 | if (!ai->ai_next) | |
1347 | error("Bind to port %s on %s failed: %.200s.", | |
1348 | strport, ntop, strerror(errno)); | |
48e671d5 | 1349 | close(listen_sock); |
1350 | continue; | |
1351 | } | |
1352 | listen_socks[num_listen_socks] = listen_sock; | |
1353 | num_listen_socks++; | |
1354 | ||
1355 | /* Start listening on the port. */ | |
fce39749 | 1356 | if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0) |
9f513268 | 1357 | fatal("listen on [%s]:%s: %.100s", |
1358 | ntop, strport, strerror(errno)); | |
1359 | logit("Server listening on %s port %s.", ntop, strport); | |
5260325f | 1360 | } |
48e671d5 | 1361 | freeaddrinfo(options.listen_addrs); |
1362 | ||
1363 | if (!num_listen_socks) | |
1364 | fatal("Cannot bind any address."); | |
1365 | ||
3aca00a3 | 1366 | if (options.protocol & SSH_PROTO_1) |
1367 | generate_ephemeral_server_key(); | |
1368 | ||
1369 | /* | |
1370 | * Arrange to restart on SIGHUP. The handler needs | |
1371 | * listen_sock. | |
1372 | */ | |
1373 | signal(SIGHUP, sighup_handler); | |
1374 | ||
1375 | signal(SIGTERM, sigterm_handler); | |
1376 | signal(SIGQUIT, sigterm_handler); | |
1377 | ||
1378 | /* Arrange SIGCHLD to be caught. */ | |
1379 | signal(SIGCHLD, main_sigchld_handler); | |
1380 | ||
1381 | /* Write out the pid file after the sigterm handler is setup */ | |
5260325f | 1382 | if (!debug_flag) { |
aa3378df | 1383 | /* |
97fb6912 | 1384 | * Record our pid in /var/run/sshd.pid to make it |
1385 | * easier to kill the correct sshd. We don't want to | |
1386 | * do this before the bind above because the bind will | |
aa3378df | 1387 | * fail if there already is a daemon, and this will |
1388 | * overwrite any old pid in the file. | |
1389 | */ | |
3c62e7eb | 1390 | f = fopen(options.pid_file, "wb"); |
71b9ced0 | 1391 | if (f == NULL) { |
1392 | error("Couldn't create pid file \"%s\": %s", | |
1393 | options.pid_file, strerror(errno)); | |
1394 | } else { | |
c457707e | 1395 | fprintf(f, "%ld\n", (long) getpid()); |
5260325f | 1396 | fclose(f); |
1397 | } | |
8efc0c15 | 1398 | } |
5260325f | 1399 | |
48e671d5 | 1400 | /* setup fd set for listen */ |
089fbbd2 | 1401 | fdset = NULL; |
48e671d5 | 1402 | maxfd = 0; |
1403 | for (i = 0; i < num_listen_socks; i++) | |
1404 | if (listen_socks[i] > maxfd) | |
1405 | maxfd = listen_socks[i]; | |
089fbbd2 | 1406 | /* pipes connected to unauthenticated childs */ |
52e3daed | 1407 | startup_pipes = xcalloc(options.max_startups, sizeof(int)); |
089fbbd2 | 1408 | for (i = 0; i < options.max_startups; i++) |
1409 | startup_pipes[i] = -1; | |
48e671d5 | 1410 | |
aa3378df | 1411 | /* |
1412 | * Stay listening for connections until the system crashes or | |
1413 | * the daemon is killed with a signal. | |
1414 | */ | |
5260325f | 1415 | for (;;) { |
1416 | if (received_sighup) | |
1417 | sighup_restart(); | |
089fbbd2 | 1418 | if (fdset != NULL) |
1419 | xfree(fdset); | |
52e3daed | 1420 | fdset = (fd_set *)xcalloc(howmany(maxfd + 1, NFDBITS), |
1421 | sizeof(fd_mask)); | |
089fbbd2 | 1422 | |
48e671d5 | 1423 | for (i = 0; i < num_listen_socks; i++) |
1424 | FD_SET(listen_socks[i], fdset); | |
089fbbd2 | 1425 | for (i = 0; i < options.max_startups; i++) |
1426 | if (startup_pipes[i] != -1) | |
1427 | FD_SET(startup_pipes[i], fdset); | |
1428 | ||
1429 | /* Wait in select until there is a connection. */ | |
59c97189 | 1430 | ret = select(maxfd+1, fdset, NULL, NULL, NULL); |
1431 | if (ret < 0 && errno != EINTR) | |
1432 | error("select: %.100s", strerror(errno)); | |
c9130033 | 1433 | if (received_sigterm) { |
bbe88b6d | 1434 | logit("Received signal %d; terminating.", |
010f9726 | 1435 | (int) received_sigterm); |
c9130033 | 1436 | close_listen_socks(); |
1437 | unlink(options.pid_file); | |
1438 | exit(255); | |
1439 | } | |
59c97189 | 1440 | if (key_used && key_do_regen) { |
cb7bd922 | 1441 | generate_ephemeral_server_key(); |
59c97189 | 1442 | key_used = 0; |
1443 | key_do_regen = 0; | |
48e671d5 | 1444 | } |
59c97189 | 1445 | if (ret < 0) |
1446 | continue; | |
1447 | ||
089fbbd2 | 1448 | for (i = 0; i < options.max_startups; i++) |
1449 | if (startup_pipes[i] != -1 && | |
1450 | FD_ISSET(startup_pipes[i], fdset)) { | |
1451 | /* | |
1452 | * the read end of the pipe is ready | |
1453 | * if the child has closed the pipe | |
8abcdba4 | 1454 | * after successful authentication |
089fbbd2 | 1455 | * or if the child has died |
1456 | */ | |
1457 | close(startup_pipes[i]); | |
1458 | startup_pipes[i] = -1; | |
1459 | startups--; | |
1460 | } | |
48e671d5 | 1461 | for (i = 0; i < num_listen_socks; i++) { |
1462 | if (!FD_ISSET(listen_socks[i], fdset)) | |
5260325f | 1463 | continue; |
089fbbd2 | 1464 | fromlen = sizeof(from); |
3efa8ea9 | 1465 | newsock = accept(listen_socks[i], |
1466 | (struct sockaddr *)&from, &fromlen); | |
089fbbd2 | 1467 | if (newsock < 0) { |
1468 | if (errno != EINTR && errno != EWOULDBLOCK) | |
1469 | error("accept: %.100s", strerror(errno)); | |
1470 | continue; | |
1471 | } | |
170694d7 | 1472 | if (unset_nonblock(newsock) == -1) { |
a666e3b1 | 1473 | close(newsock); |
1474 | continue; | |
1475 | } | |
c345cf9d | 1476 | if (drop_connection(startups) == 1) { |
1477 | debug("drop connection #%d", startups); | |
089fbbd2 | 1478 | close(newsock); |
1479 | continue; | |
1480 | } | |
1481 | if (pipe(startup_p) == -1) { | |
1482 | close(newsock); | |
1483 | continue; | |
1484 | } | |
1485 | ||
b9a549d7 | 1486 | if (rexec_flag && socketpair(AF_UNIX, |
1487 | SOCK_STREAM, 0, config_s) == -1) { | |
1488 | error("reexec socketpair: %s", | |
1489 | strerror(errno)); | |
1490 | close(newsock); | |
1491 | close(startup_p[0]); | |
1492 | close(startup_p[1]); | |
1493 | continue; | |
1494 | } | |
1495 | ||
089fbbd2 | 1496 | for (j = 0; j < options.max_startups; j++) |
1497 | if (startup_pipes[j] == -1) { | |
1498 | startup_pipes[j] = startup_p[0]; | |
1499 | if (maxfd < startup_p[0]) | |
1500 | maxfd = startup_p[0]; | |
1501 | startups++; | |
1502 | break; | |
1503 | } | |
2b87da3b | 1504 | |
aa3378df | 1505 | /* |
089fbbd2 | 1506 | * Got connection. Fork a child to handle it, unless |
1507 | * we are in debugging mode. | |
aa3378df | 1508 | */ |
089fbbd2 | 1509 | if (debug_flag) { |
aa3378df | 1510 | /* |
089fbbd2 | 1511 | * In debugging mode. Close the listening |
1512 | * socket, and start processing the | |
1513 | * connection without forking. | |
aa3378df | 1514 | */ |
089fbbd2 | 1515 | debug("Server will not fork when running in debugging mode."); |
48e671d5 | 1516 | close_listen_socks(); |
5260325f | 1517 | sock_in = newsock; |
1518 | sock_out = newsock; | |
b9a549d7 | 1519 | close(startup_p[0]); |
1520 | close(startup_p[1]); | |
5540ea9b | 1521 | startup_pipe = -1; |
3f7a7e4a | 1522 | pid = getpid(); |
b9a549d7 | 1523 | if (rexec_flag) { |
1524 | send_rexec_state(config_s[0], | |
1525 | &cfg); | |
1526 | close(config_s[0]); | |
1527 | } | |
5260325f | 1528 | break; |
089fbbd2 | 1529 | } else { |
1530 | /* | |
1531 | * Normal production daemon. Fork, and have | |
1532 | * the child process the connection. The | |
1533 | * parent continues listening. | |
1534 | */ | |
1535 | if ((pid = fork()) == 0) { | |
1536 | /* | |
3efa8ea9 | 1537 | * Child. Close the listening and |
1538 | * max_startup sockets. Start using | |
1539 | * the accepted socket. Reinitialize | |
1540 | * logging (since our pid has changed). | |
1541 | * We break out of the loop to handle | |
089fbbd2 | 1542 | * the connection. |
1543 | */ | |
1544 | startup_pipe = startup_p[1]; | |
7ace8c3b | 1545 | close_startup_pipes(); |
089fbbd2 | 1546 | close_listen_socks(); |
1547 | sock_in = newsock; | |
1548 | sock_out = newsock; | |
3efa8ea9 | 1549 | log_init(__progname, |
1550 | options.log_level, | |
1551 | options.log_facility, | |
1552 | log_stderr); | |
9216f89c | 1553 | if (rexec_flag) |
1554 | close(config_s[0]); | |
089fbbd2 | 1555 | break; |
1556 | } | |
5260325f | 1557 | } |
5260325f | 1558 | |
089fbbd2 | 1559 | /* Parent. Stay in the loop. */ |
1560 | if (pid < 0) | |
1561 | error("fork: %.100s", strerror(errno)); | |
1562 | else | |
c457707e | 1563 | debug("Forked child %ld.", (long)pid); |
5260325f | 1564 | |
089fbbd2 | 1565 | close(startup_p[1]); |
5260325f | 1566 | |
b9a549d7 | 1567 | if (rexec_flag) { |
1568 | send_rexec_state(config_s[0], &cfg); | |
1569 | close(config_s[0]); | |
1570 | close(config_s[1]); | |
1571 | } | |
1572 | ||
3efa8ea9 | 1573 | /* |
1574 | * Mark that the key has been used (it | |
1575 | * was "given" to the child). | |
1576 | */ | |
59c97189 | 1577 | if ((options.protocol & SSH_PROTO_1) && |
1578 | key_used == 0) { | |
1579 | /* Schedule server key regeneration alarm. */ | |
f00d1f78 | 1580 | signal(SIGALRM, key_regeneration_alarm); |
59c97189 | 1581 | alarm(options.key_regeneration_time); |
1582 | key_used = 1; | |
1583 | } | |
5260325f | 1584 | |
089fbbd2 | 1585 | arc4random_stir(); |
089fbbd2 | 1586 | close(newsock); |
1587 | } | |
48e671d5 | 1588 | /* child process check (or debug mode) */ |
1589 | if (num_listen_socks < 0) | |
1590 | break; | |
5260325f | 1591 | } |
1592 | } | |
8efc0c15 | 1593 | |
5260325f | 1594 | /* This is the child processing a new connection. */ |
cc120685 | 1595 | setproctitle("%s", "[accepted]"); |
5260325f | 1596 | |
8b758bd2 | 1597 | /* |
1598 | * Create a new session and process group since the 4.4BSD | |
1599 | * setlogin() affects the entire process group. We don't | |
1600 | * want the child to be able to affect the parent. | |
1601 | */ | |
1602 | #if !defined(SSHD_ACQUIRES_CTTY) | |
1603 | /* | |
1604 | * If setsid is called, on some platforms sshd will later acquire a | |
1605 | * controlling terminal which will result in "could not set | |
1606 | * controlling tty" errors. | |
1607 | */ | |
1608 | if (!debug_flag && !inetd_flag && setsid() < 0) | |
1609 | error("setsid: %.100s", strerror(errno)); | |
1610 | #endif | |
1611 | ||
b9a549d7 | 1612 | if (rexec_flag) { |
1613 | int fd; | |
1614 | ||
b250e837 | 1615 | debug("rexec start in %d out %d newsock %d pipe %d sock %d", |
1616 | sock_in, sock_out, newsock, startup_pipe, config_s[0]); | |
b9a549d7 | 1617 | dup2(newsock, STDIN_FILENO); |
1618 | dup2(STDIN_FILENO, STDOUT_FILENO); | |
1619 | if (startup_pipe == -1) | |
b250e837 | 1620 | close(REEXEC_STARTUP_PIPE_FD); |
b9a549d7 | 1621 | else |
b250e837 | 1622 | dup2(startup_pipe, REEXEC_STARTUP_PIPE_FD); |
b9a549d7 | 1623 | |
b250e837 | 1624 | dup2(config_s[1], REEXEC_CONFIG_PASS_FD); |
b9a549d7 | 1625 | close(config_s[1]); |
ad148c04 | 1626 | if (startup_pipe != -1) |
1627 | close(startup_pipe); | |
b250e837 | 1628 | |
b9a549d7 | 1629 | execv(rexec_argv[0], rexec_argv); |
1630 | ||
1631 | /* Reexec has failed, fall back and continue */ | |
1632 | error("rexec of %s failed: %s", rexec_argv[0], strerror(errno)); | |
b250e837 | 1633 | recv_rexec_state(REEXEC_CONFIG_PASS_FD, NULL); |
b9a549d7 | 1634 | log_init(__progname, options.log_level, |
1635 | options.log_facility, log_stderr); | |
1636 | ||
1637 | /* Clean up fds */ | |
b250e837 | 1638 | startup_pipe = REEXEC_STARTUP_PIPE_FD; |
b9a549d7 | 1639 | close(config_s[1]); |
b250e837 | 1640 | close(REEXEC_CONFIG_PASS_FD); |
1641 | newsock = sock_out = sock_in = dup(STDIN_FILENO); | |
b9a549d7 | 1642 | if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { |
1643 | dup2(fd, STDIN_FILENO); | |
1644 | dup2(fd, STDOUT_FILENO); | |
1645 | if (fd > STDERR_FILENO) | |
1646 | close(fd); | |
1647 | } | |
b250e837 | 1648 | debug("rexec cleanup in %d out %d newsock %d pipe %d sock %d", |
1649 | sock_in, sock_out, newsock, startup_pipe, config_s[0]); | |
b9a549d7 | 1650 | } |
1651 | ||
aa3378df | 1652 | /* |
1653 | * Disable the key regeneration alarm. We will not regenerate the | |
1654 | * key since we are no longer in a position to give it to anyone. We | |
1655 | * will not restart on SIGHUP since it no longer makes sense. | |
1656 | */ | |
5260325f | 1657 | alarm(0); |
1658 | signal(SIGALRM, SIG_DFL); | |
1659 | signal(SIGHUP, SIG_DFL); | |
1660 | signal(SIGTERM, SIG_DFL); | |
1661 | signal(SIGQUIT, SIG_DFL); | |
1662 | signal(SIGCHLD, SIG_DFL); | |
9aaf9be4 | 1663 | signal(SIGINT, SIG_DFL); |
5260325f | 1664 | |
aa3378df | 1665 | /* |
1666 | * Register our connection. This turns encryption off because we do | |
1667 | * not have a key. | |
1668 | */ | |
5260325f | 1669 | packet_set_connection(sock_in, sock_out); |
07200973 | 1670 | packet_set_server(); |
5260325f | 1671 | |
7c3bc5a2 | 1672 | /* Set SO_KEEPALIVE if requested. */ |
1673 | if (options.tcp_keep_alive && packet_connection_is_on_socket() && | |
1674 | setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) < 0) | |
1675 | error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); | |
1676 | ||
29798ed0 | 1677 | if ((remote_port = get_remote_port()) < 0) { |
1678 | debug("get_remote_port failed"); | |
1679 | cleanup_exit(255); | |
1680 | } | |
3a85986d | 1681 | |
1682 | /* | |
1683 | * We use get_canonical_hostname with usedns = 0 instead of | |
1684 | * get_remote_ipaddr here so IP options will be checked. | |
1685 | */ | |
211f229e | 1686 | (void) get_canonical_hostname(0); |
1687 | /* | |
1688 | * The rest of the code depends on the fact that | |
1689 | * get_remote_ipaddr() caches the remote ip, even if | |
1690 | * the socket goes away. | |
1691 | */ | |
1692 | remote_ip = get_remote_ipaddr(); | |
5260325f | 1693 | |
6039eeef | 1694 | #ifdef SSH_AUDIT_EVENTS |
c00e4d75 | 1695 | audit_connection_from(remote_ip, remote_port); |
1696 | #endif | |
5260325f | 1697 | #ifdef LIBWRAP |
ac28afd8 | 1698 | /* Check whether logins are denied from this host. */ |
33e5359c | 1699 | if (packet_connection_is_on_socket()) { |
5260325f | 1700 | struct request_info req; |
8efc0c15 | 1701 | |
8fbc356d | 1702 | request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0); |
5260325f | 1703 | fromhost(&req); |
8efc0c15 | 1704 | |
5260325f | 1705 | if (!hosts_access(&req)) { |
ac28afd8 | 1706 | debug("Connection refused by tcp wrapper"); |
563834bb | 1707 | refuse(&req); |
ac28afd8 | 1708 | /* NOTREACHED */ |
1709 | fatal("libwrap refuse returns"); | |
5260325f | 1710 | } |
8efc0c15 | 1711 | } |
48e671d5 | 1712 | #endif /* LIBWRAP */ |
ac28afd8 | 1713 | |
5260325f | 1714 | /* Log the connection. */ |
1715 | verbose("Connection from %.500s port %d", remote_ip, remote_port); | |
8efc0c15 | 1716 | |
aa3378df | 1717 | /* |
7b9b0103 | 1718 | * We don't want to listen forever unless the other side |
aa3378df | 1719 | * successfully authenticates itself. So we set up an alarm which is |
1720 | * cleared after successful authentication. A limit of zero | |
7b9b0103 | 1721 | * indicates no limit. Note that we don't set the alarm in debugging |
aa3378df | 1722 | * mode; it is just annoying to have the server exit just when you |
1723 | * are about to discover the bug. | |
1724 | */ | |
f00d1f78 | 1725 | signal(SIGALRM, grace_alarm_handler); |
5260325f | 1726 | if (!debug_flag) |
1727 | alarm(options.login_grace_time); | |
1728 | ||
7368a6c8 | 1729 | sshd_exchange_identification(sock_in, sock_out); |
0598d99d | 1730 | |
5260325f | 1731 | packet_set_nonblocking(); |
1732 | ||
2362db19 | 1733 | /* allocate authentication context */ |
52e3daed | 1734 | authctxt = xcalloc(1, sizeof(*authctxt)); |
2362db19 | 1735 | |
1b394137 | 1736 | authctxt->loginmsg = &loginmsg; |
1737 | ||
2362db19 | 1738 | /* XXX global for cleanup, access from other modules */ |
1739 | the_authctxt = authctxt; | |
1740 | ||
022487ce | 1741 | /* prepare buffer to collect messages to display to user after login */ |
1742 | buffer_init(&loginmsg); | |
1743 | ||
324bf712 | 1744 | if (use_privsep) |
2362db19 | 1745 | if (privsep_preauth(authctxt) == 1) |
324bf712 | 1746 | goto authenticated; |
1853d1ef | 1747 | |
7b2ea3a1 | 1748 | /* perform the key exchange */ |
7b2ea3a1 | 1749 | /* authenticate user and start session */ |
e78a59f5 | 1750 | if (compat20) { |
1751 | do_ssh2_kex(); | |
2362db19 | 1752 | do_authentication2(authctxt); |
e78a59f5 | 1753 | } else { |
1754 | do_ssh1_kex(); | |
2362db19 | 1755 | do_authentication(authctxt); |
e78a59f5 | 1756 | } |
324bf712 | 1757 | /* |
1758 | * If we use privilege separation, the unprivileged child transfers | |
1759 | * the current keystate and exits | |
1760 | */ | |
1761 | if (use_privsep) { | |
b5a28cbc | 1762 | mm_send_keystate(pmonitor); |
1853d1ef | 1763 | exit(0); |
324bf712 | 1764 | } |
1853d1ef | 1765 | |
1766 | authenticated: | |
678143bd | 1767 | /* |
1768 | * Cancel the alarm we set to limit the time taken for | |
1769 | * authentication. | |
1770 | */ | |
1771 | alarm(0); | |
1772 | signal(SIGALRM, SIG_DFL); | |
1773 | if (startup_pipe != -1) { | |
1774 | close(startup_pipe); | |
1775 | startup_pipe = -1; | |
1776 | } | |
1777 | ||
6039eeef | 1778 | #ifdef SSH_AUDIT_EVENTS |
1779 | audit_event(SSH_AUTH_SUCCESS); | |
c00e4d75 | 1780 | #endif |
1781 | ||
762715ce | 1782 | /* |
1853d1ef | 1783 | * In privilege separation, we fork another child and prepare |
1784 | * file descriptor passing. | |
1785 | */ | |
1786 | if (use_privsep) { | |
324bf712 | 1787 | privsep_postauth(authctxt); |
1788 | /* the monitor process [priv] will not return */ | |
1853d1ef | 1789 | if (!compat20) |
1790 | destroy_sensitive_data(); | |
1791 | } | |
1b34c1b3 | 1792 | |
2362db19 | 1793 | /* Start session. */ |
1b34c1b3 | 1794 | do_authenticated(authctxt); |
1795 | ||
63284fbb | 1796 | /* The connection has been terminated. */ |
1797 | verbose("Closing connection to %.100s", remote_ip); | |
8efc0c15 | 1798 | |
d94aa2ae | 1799 | #ifdef USE_PAM |
7fceb20d | 1800 | if (options.use_pam) |
1801 | finish_pam(); | |
d94aa2ae | 1802 | #endif /* USE_PAM */ |
8efc0c15 | 1803 | |
2b0c0925 | 1804 | #ifdef SSH_AUDIT_EVENTS |
1805 | PRIVSEP(audit_event(SSH_CONNECTION_CLOSE)); | |
1806 | #endif | |
1807 | ||
5260325f | 1808 | packet_close(); |
1853d1ef | 1809 | |
1810 | if (use_privsep) | |
1811 | mm_terminate(); | |
1812 | ||
5260325f | 1813 | exit(0); |
1814 | } | |
8efc0c15 | 1815 | |
4f08e98d | 1816 | /* |
1817 | * Decrypt session_key_int using our private server key and private host key | |
1818 | * (key with larger modulus first). | |
1819 | */ | |
1853d1ef | 1820 | int |
4f08e98d | 1821 | ssh1_session_key(BIGNUM *session_key_int) |
1822 | { | |
1823 | int rsafail = 0; | |
1824 | ||
3efa8ea9 | 1825 | if (BN_cmp(sensitive_data.server_key->rsa->n, |
1826 | sensitive_data.ssh1_host_key->rsa->n) > 0) { | |
4f08e98d | 1827 | /* Server key has bigger modulus. */ |
1828 | if (BN_num_bits(sensitive_data.server_key->rsa->n) < | |
3efa8ea9 | 1829 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + |
1830 | SSH_KEY_BITS_RESERVED) { | |
1831 | fatal("do_connection: %s: " | |
1832 | "server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d", | |
4f08e98d | 1833 | get_remote_ipaddr(), |
1834 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
1835 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), | |
1836 | SSH_KEY_BITS_RESERVED); | |
1837 | } | |
1838 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1839 | sensitive_data.server_key->rsa) <= 0) | |
1840 | rsafail++; | |
1841 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1842 | sensitive_data.ssh1_host_key->rsa) <= 0) | |
1843 | rsafail++; | |
1844 | } else { | |
1845 | /* Host key has bigger modulus (or they are equal). */ | |
1846 | if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) < | |
3efa8ea9 | 1847 | BN_num_bits(sensitive_data.server_key->rsa->n) + |
1848 | SSH_KEY_BITS_RESERVED) { | |
1849 | fatal("do_connection: %s: " | |
1850 | "host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d", | |
4f08e98d | 1851 | get_remote_ipaddr(), |
1852 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), | |
1853 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
1854 | SSH_KEY_BITS_RESERVED); | |
1855 | } | |
1856 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1857 | sensitive_data.ssh1_host_key->rsa) < 0) | |
1858 | rsafail++; | |
1859 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1860 | sensitive_data.server_key->rsa) < 0) | |
1861 | rsafail++; | |
1862 | } | |
1863 | return (rsafail); | |
1864 | } | |
5260325f | 1865 | /* |
7b2ea3a1 | 1866 | * SSH1 key exchange |
5260325f | 1867 | */ |
396c147e | 1868 | static void |
1e3b8b07 | 1869 | do_ssh1_kex(void) |
8efc0c15 | 1870 | { |
5260325f | 1871 | int i, len; |
46aa2d1f | 1872 | int rsafail = 0; |
5260325f | 1873 | BIGNUM *session_key_int; |
1e3b8b07 | 1874 | u_char session_key[SSH_SESSION_KEY_LENGTH]; |
1875 | u_char cookie[8]; | |
1876 | u_int cipher_type, auth_mask, protocol_flags; | |
7fdc56c5 | 1877 | u_int32_t rnd = 0; |
5260325f | 1878 | |
aa3378df | 1879 | /* |
1880 | * Generate check bytes that the client must send back in the user | |
1881 | * packet in order for it to be accepted; this is used to defy ip | |
1882 | * spoofing attacks. Note that this only works against somebody | |
1883 | * doing IP spoofing from a remote machine; any machine on the local | |
1884 | * network can still see outgoing packets and catch the random | |
1885 | * cookie. This only affects rhosts authentication, and this is one | |
1886 | * of the reasons why it is inherently insecure. | |
1887 | */ | |
5260325f | 1888 | for (i = 0; i < 8; i++) { |
1889 | if (i % 4 == 0) | |
7fdc56c5 | 1890 | rnd = arc4random(); |
1891 | cookie[i] = rnd & 0xff; | |
1892 | rnd >>= 8; | |
5260325f | 1893 | } |
1894 | ||
aa3378df | 1895 | /* |
1896 | * Send our public key. We include in the packet 64 bits of random | |
1897 | * data that must be matched in the reply in order to prevent IP | |
1898 | * spoofing. | |
1899 | */ | |
5260325f | 1900 | packet_start(SSH_SMSG_PUBLIC_KEY); |
1901 | for (i = 0; i < 8; i++) | |
7b2ea3a1 | 1902 | packet_put_char(cookie[i]); |
5260325f | 1903 | |
1904 | /* Store our public server RSA key. */ | |
fa08c86b | 1905 | packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n)); |
1906 | packet_put_bignum(sensitive_data.server_key->rsa->e); | |
1907 | packet_put_bignum(sensitive_data.server_key->rsa->n); | |
5260325f | 1908 | |
1909 | /* Store our public host RSA key. */ | |
fa08c86b | 1910 | packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); |
1911 | packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e); | |
1912 | packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n); | |
5260325f | 1913 | |
1914 | /* Put protocol flags. */ | |
1915 | packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN); | |
1916 | ||
1917 | /* Declare which ciphers we support. */ | |
94ec8c6b | 1918 | packet_put_int(cipher_mask_ssh1(0)); |
5260325f | 1919 | |
1920 | /* Declare supported authentication types. */ | |
1921 | auth_mask = 0; | |
5260325f | 1922 | if (options.rhosts_rsa_authentication) |
1923 | auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA; | |
1924 | if (options.rsa_authentication) | |
1925 | auth_mask |= 1 << SSH_AUTH_RSA; | |
5ba55ada | 1926 | if (options.challenge_response_authentication == 1) |
5260325f | 1927 | auth_mask |= 1 << SSH_AUTH_TIS; |
5260325f | 1928 | if (options.password_authentication) |
1929 | auth_mask |= 1 << SSH_AUTH_PASSWORD; | |
1930 | packet_put_int(auth_mask); | |
1931 | ||
1932 | /* Send the packet and wait for it to be sent. */ | |
1933 | packet_send(); | |
1934 | packet_write_wait(); | |
1935 | ||
fa08c86b | 1936 | debug("Sent %d bit server key and %d bit host key.", |
1937 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
1938 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); | |
5260325f | 1939 | |
1940 | /* Read clients reply (cipher type and session key). */ | |
54a5250f | 1941 | packet_read_expect(SSH_CMSG_SESSION_KEY); |
5260325f | 1942 | |
2d86a6cc | 1943 | /* Get cipher type and check whether we accept this. */ |
5260325f | 1944 | cipher_type = packet_get_char(); |
1945 | ||
94ec8c6b | 1946 | if (!(cipher_mask_ssh1(0) & (1 << cipher_type))) |
2d86a6cc | 1947 | packet_disconnect("Warning: client selects unsupported cipher."); |
1948 | ||
5260325f | 1949 | /* Get check bytes from the packet. These must match those we |
1950 | sent earlier with the public key packet. */ | |
1951 | for (i = 0; i < 8; i++) | |
7b2ea3a1 | 1952 | if (cookie[i] != packet_get_char()) |
5260325f | 1953 | packet_disconnect("IP Spoofing check bytes do not match."); |
1954 | ||
1955 | debug("Encryption type: %.200s", cipher_name(cipher_type)); | |
1956 | ||
1957 | /* Get the encrypted integer. */ | |
b775c6f2 | 1958 | if ((session_key_int = BN_new()) == NULL) |
1959 | fatal("do_ssh1_kex: BN_new failed"); | |
20b279e6 | 1960 | packet_get_bignum(session_key_int); |
5260325f | 1961 | |
5260325f | 1962 | protocol_flags = packet_get_int(); |
1963 | packet_set_protocol_flags(protocol_flags); | |
95500969 | 1964 | packet_check_eom(); |
5260325f | 1965 | |
4f08e98d | 1966 | /* Decrypt session_key_int using host/server keys */ |
1853d1ef | 1967 | rsafail = PRIVSEP(ssh1_session_key(session_key_int)); |
1968 | ||
aa3378df | 1969 | /* |
1970 | * Extract session key from the decrypted integer. The key is in the | |
1971 | * least significant 256 bits of the integer; the first byte of the | |
1972 | * key is in the highest bits. | |
1973 | */ | |
46aa2d1f | 1974 | if (!rsafail) { |
1975 | BN_mask_bits(session_key_int, sizeof(session_key) * 8); | |
1976 | len = BN_num_bytes(session_key_int); | |
2ceb8101 | 1977 | if (len < 0 || (u_int)len > sizeof(session_key)) { |
46aa2d1f | 1978 | error("do_connection: bad session key len from %s: " |
5ca51e19 | 1979 | "session_key_int %d > sizeof(session_key) %lu", |
1980 | get_remote_ipaddr(), len, (u_long)sizeof(session_key)); | |
46aa2d1f | 1981 | rsafail++; |
1982 | } else { | |
1983 | memset(session_key, 0, sizeof(session_key)); | |
1984 | BN_bn2bin(session_key_int, | |
1985 | session_key + sizeof(session_key) - len); | |
00be5382 | 1986 | |
8bbf1fa6 | 1987 | derive_ssh1_session_id( |
f2107e97 | 1988 | sensitive_data.ssh1_host_key->rsa->n, |
8bbf1fa6 | 1989 | sensitive_data.server_key->rsa->n, |
1990 | cookie, session_id); | |
00be5382 | 1991 | /* |
1992 | * Xor the first 16 bytes of the session key with the | |
1993 | * session id. | |
1994 | */ | |
1995 | for (i = 0; i < 16; i++) | |
1996 | session_key[i] ^= session_id[i]; | |
46aa2d1f | 1997 | } |
1998 | } | |
1999 | if (rsafail) { | |
00be5382 | 2000 | int bytes = BN_num_bytes(session_key_int); |
f6b1ba8f | 2001 | u_char *buf = xmalloc(bytes); |
00be5382 | 2002 | MD5_CTX md; |
2003 | ||
bbe88b6d | 2004 | logit("do_connection: generating a fake encryption key"); |
00be5382 | 2005 | BN_bn2bin(session_key_int, buf); |
2006 | MD5_Init(&md); | |
2007 | MD5_Update(&md, buf, bytes); | |
2008 | MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); | |
2009 | MD5_Final(session_key, &md); | |
2010 | MD5_Init(&md); | |
2011 | MD5_Update(&md, session_key, 16); | |
2012 | MD5_Update(&md, buf, bytes); | |
2013 | MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); | |
2014 | MD5_Final(session_key + 16, &md); | |
2015 | memset(buf, 0, bytes); | |
2016 | xfree(buf); | |
0572fe75 | 2017 | for (i = 0; i < 16; i++) |
2018 | session_id[i] = session_key[i] ^ session_key[i + 16]; | |
46aa2d1f | 2019 | } |
1853d1ef | 2020 | /* Destroy the private and public keys. No longer. */ |
63284fbb | 2021 | destroy_sensitive_data(); |
00be5382 | 2022 | |
1853d1ef | 2023 | if (use_privsep) |
2024 | mm_ssh1_session_id(session_id); | |
2025 | ||
7b2ea3a1 | 2026 | /* Destroy the decrypted integer. It is no longer needed. */ |
2027 | BN_clear_free(session_key_int); | |
2028 | ||
5260325f | 2029 | /* Set the session key. From this on all communications will be encrypted. */ |
2030 | packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type); | |
2031 | ||
2032 | /* Destroy our copy of the session key. It is no longer needed. */ | |
2033 | memset(session_key, 0, sizeof(session_key)); | |
2034 | ||
2035 | debug("Received session key; encryption turned on."); | |
2036 | ||
c242fc96 | 2037 | /* Send an acknowledgment packet. Note that this packet is sent encrypted. */ |
5260325f | 2038 | packet_start(SSH_SMSG_SUCCESS); |
2039 | packet_send(); | |
2040 | packet_write_wait(); | |
5260325f | 2041 | } |
e78a59f5 | 2042 | |
2043 | /* | |
2044 | * SSH2 key exchange: diffie-hellman-group1-sha1 | |
2045 | */ | |
396c147e | 2046 | static void |
1e3b8b07 | 2047 | do_ssh2_kex(void) |
e78a59f5 | 2048 | { |
e78a59f5 | 2049 | Kex *kex; |
e78a59f5 | 2050 | |
a8be9f80 | 2051 | if (options.ciphers != NULL) { |
6ae2364d | 2052 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = |
a8be9f80 | 2053 | myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; |
2054 | } | |
1ad64a93 | 2055 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = |
2056 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]); | |
2057 | myproposal[PROPOSAL_ENC_ALGS_STOC] = | |
2058 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); | |
2059 | ||
b2552997 | 2060 | if (options.macs != NULL) { |
2061 | myproposal[PROPOSAL_MAC_ALGS_CTOS] = | |
2062 | myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; | |
2063 | } | |
07200973 | 2064 | if (options.compression == COMP_NONE) { |
636f76ca | 2065 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = |
2066 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "none"; | |
07200973 | 2067 | } else if (options.compression == COMP_DELAYED) { |
2068 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = | |
2069 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com"; | |
636f76ca | 2070 | } |
3efa8ea9 | 2071 | |
fa08c86b | 2072 | myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = list_hostkey_types(); |
2073 | ||
7a37c112 | 2074 | /* start key exchange */ |
d8ee838b | 2075 | kex = kex_setup(myproposal); |
98a58eda | 2076 | kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server; |
41e5bd9a | 2077 | kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server; |
98a58eda | 2078 | kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; |
2ff8003a | 2079 | kex->kex[KEX_DH_GEX_SHA256] = kexgex_server; |
a5c9ffdb | 2080 | kex->server = 1; |
2081 | kex->client_version_string=client_version_string; | |
2082 | kex->server_version_string=server_version_string; | |
2083 | kex->load_host_key=&get_hostkey_by_type; | |
1853d1ef | 2084 | kex->host_key_index=&get_hostkey_index; |
94ec8c6b | 2085 | |
7a37c112 | 2086 | xxx_kex = kex; |
2087 | ||
c422989b | 2088 | dispatch_run(DISPATCH_BLOCK, &kex->done, kex); |
94ec8c6b | 2089 | |
d1ac6175 | 2090 | session_id2 = kex->session_id; |
2091 | session_id2_len = kex->session_id_len; | |
2092 | ||
94ec8c6b | 2093 | #ifdef DEBUG_KEXDH |
2094 | /* send 1st encrypted/maced/compressed message */ | |
2095 | packet_start(SSH2_MSG_IGNORE); | |
2096 | packet_put_cstring("markus"); | |
2097 | packet_send(); | |
2098 | packet_write_wait(); | |
2099 | #endif | |
a5c9ffdb | 2100 | debug("KEX done"); |
e78a59f5 | 2101 | } |
2362db19 | 2102 | |
2103 | /* server specific fatal cleanup */ | |
2104 | void | |
2105 | cleanup_exit(int i) | |
2106 | { | |
2107 | if (the_authctxt) | |
2108 | do_cleanup(the_authctxt); | |
6039eeef | 2109 | #ifdef SSH_AUDIT_EVENTS |
c00e4d75 | 2110 | /* done after do_cleanup so it can cancel the PAM auth 'thread' */ |
2111 | if (!use_privsep || mm_is_monitor()) | |
6039eeef | 2112 | audit_event(SSH_CONNECTION_ABANDON); |
c00e4d75 | 2113 | #endif |
2362db19 | 2114 | _exit(i); |
2115 | } |