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e264ac72 | 1 | /* $OpenBSD: sshd.c,v 1.340 2006/07/25 02:59:21 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> |
00146caa | 67 | #include <string.h> |
8efc0c15 | 68 | |
42f11eb2 | 69 | #include <openssl/dh.h> |
70 | #include <openssl/bn.h> | |
436c347c | 71 | #include <openssl/md5.h> |
1853d1ef | 72 | #include <openssl/rand.h> |
6e879cb4 | 73 | #ifdef HAVE_SECUREWARE |
74 | #include <sys/security.h> | |
75 | #include <prot.h> | |
76 | #endif | |
42f11eb2 | 77 | |
78 | #include "ssh.h" | |
79 | #include "ssh1.h" | |
80 | #include "ssh2.h" | |
8efc0c15 | 81 | #include "xmalloc.h" |
82 | #include "rsa.h" | |
1729c161 | 83 | #include "sshpty.h" |
8efc0c15 | 84 | #include "packet.h" |
42f11eb2 | 85 | #include "log.h" |
8efc0c15 | 86 | #include "servconf.h" |
87 | #include "uidswap.h" | |
88 | #include "compat.h" | |
7368a6c8 | 89 | #include "buffer.h" |
b9a549d7 | 90 | #include "bufaux.h" |
42f11eb2 | 91 | #include "cipher.h" |
e78a59f5 | 92 | #include "kex.h" |
7368a6c8 | 93 | #include "key.h" |
94ec8c6b | 94 | #include "dh.h" |
e78a59f5 | 95 | #include "myproposal.h" |
a306f2dd | 96 | #include "authfile.h" |
42f11eb2 | 97 | #include "pathnames.h" |
98 | #include "atomicio.h" | |
99 | #include "canohost.h" | |
100 | #include "auth.h" | |
101 | #include "misc.h" | |
b9a549d7 | 102 | #include "msg.h" |
a5c9ffdb | 103 | #include "dispatch.h" |
e4d7f734 | 104 | #include "channels.h" |
1b34c1b3 | 105 | #include "session.h" |
1853d1ef | 106 | #include "monitor_mm.h" |
107 | #include "monitor.h" | |
108 | #include "monitor_wrap.h" | |
109 | #include "monitor_fdpass.h" | |
28015df4 | 110 | #include "version.h" |
8efc0c15 | 111 | |
112 | #ifdef LIBWRAP | |
113 | #include <tcpd.h> | |
114 | #include <syslog.h> | |
115 | int allow_severity = LOG_INFO; | |
116 | int deny_severity = LOG_WARNING; | |
117 | #endif /* LIBWRAP */ | |
118 | ||
119 | #ifndef O_NOCTTY | |
120 | #define O_NOCTTY 0 | |
121 | #endif | |
122 | ||
b250e837 | 123 | /* Re-exec fds */ |
124 | #define REEXEC_DEVCRYPTO_RESERVED_FD (STDERR_FILENO + 1) | |
125 | #define REEXEC_STARTUP_PIPE_FD (STDERR_FILENO + 2) | |
126 | #define REEXEC_CONFIG_PASS_FD (STDERR_FILENO + 3) | |
127 | #define REEXEC_MIN_FREE_FD (STDERR_FILENO + 4) | |
128 | ||
260d427b | 129 | extern char *__progname; |
260d427b | 130 | |
8efc0c15 | 131 | /* Server configuration options. */ |
132 | ServerOptions options; | |
133 | ||
134 | /* Name of the server configuration file. */ | |
42f11eb2 | 135 | char *config_file_name = _PATH_SERVER_CONFIG_FILE; |
8efc0c15 | 136 | |
5260325f | 137 | /* |
138 | * Debug mode flag. This can be set on the command line. If debug | |
139 | * mode is enabled, extra debugging output will be sent to the system | |
140 | * log, the daemon will not go to background, and will exit after processing | |
141 | * the first connection. | |
142 | */ | |
8efc0c15 | 143 | int debug_flag = 0; |
144 | ||
f87f09aa | 145 | /* Flag indicating that the daemon should only test the configuration and keys. */ |
146 | int test_flag = 0; | |
147 | ||
8efc0c15 | 148 | /* Flag indicating that the daemon is being started from inetd. */ |
149 | int inetd_flag = 0; | |
150 | ||
0b6fbf03 | 151 | /* Flag indicating that sshd should not detach and become a daemon. */ |
152 | int no_daemon_flag = 0; | |
153 | ||
6a17f9c2 | 154 | /* debug goes to stderr unless inetd_flag is set */ |
155 | int log_stderr = 0; | |
156 | ||
8efc0c15 | 157 | /* Saved arguments to main(). */ |
158 | char **saved_argv; | |
4d33e531 | 159 | int saved_argc; |
8efc0c15 | 160 | |
b9a549d7 | 161 | /* re-exec */ |
162 | int rexeced_flag = 0; | |
163 | int rexec_flag = 1; | |
164 | int rexec_argc = 0; | |
165 | char **rexec_argv; | |
166 | ||
aa3378df | 167 | /* |
48e671d5 | 168 | * The sockets that the server is listening; this is used in the SIGHUP |
169 | * signal handler. | |
aa3378df | 170 | */ |
48e671d5 | 171 | #define MAX_LISTEN_SOCKS 16 |
172 | int listen_socks[MAX_LISTEN_SOCKS]; | |
173 | int num_listen_socks = 0; | |
8efc0c15 | 174 | |
aa3378df | 175 | /* |
176 | * the client's version string, passed by sshd2 in compat mode. if != NULL, | |
177 | * sshd will skip the version-number exchange | |
178 | */ | |
5260325f | 179 | char *client_version_string = NULL; |
7368a6c8 | 180 | char *server_version_string = NULL; |
8efc0c15 | 181 | |
7a37c112 | 182 | /* for rekeying XXX fixme */ |
183 | Kex *xxx_kex; | |
184 | ||
aa3378df | 185 | /* |
186 | * Any really sensitive data in the application is contained in this | |
187 | * structure. The idea is that this structure could be locked into memory so | |
188 | * that the pages do not get written into swap. However, there are some | |
189 | * problems. The private key contains BIGNUMs, and we do not (in principle) | |
190 | * have access to the internals of them, and locking just the structure is | |
191 | * not very useful. Currently, memory locking is not implemented. | |
192 | */ | |
5260325f | 193 | struct { |
cb7bd922 | 194 | Key *server_key; /* ephemeral server key */ |
fa08c86b | 195 | Key *ssh1_host_key; /* ssh1 host key */ |
196 | Key **host_keys; /* all private host keys */ | |
197 | int have_ssh1_key; | |
198 | int have_ssh2_key; | |
00be5382 | 199 | u_char ssh1_cookie[SSH_SESSION_KEY_LENGTH]; |
8efc0c15 | 200 | } sensitive_data; |
201 | ||
aa3378df | 202 | /* |
59c97189 | 203 | * Flag indicating whether the RSA server key needs to be regenerated. |
204 | * Is set in the SIGALRM handler and cleared when the key is regenerated. | |
aa3378df | 205 | */ |
7a934d1b | 206 | static volatile sig_atomic_t key_do_regen = 0; |
8efc0c15 | 207 | |
c9130033 | 208 | /* This is set to true when a signal is received. */ |
7a934d1b | 209 | static volatile sig_atomic_t received_sighup = 0; |
210 | static volatile sig_atomic_t received_sigterm = 0; | |
8efc0c15 | 211 | |
7368a6c8 | 212 | /* session identifier, used by RSA-auth */ |
1e3b8b07 | 213 | u_char session_id[16]; |
e7c0f9d5 | 214 | |
a306f2dd | 215 | /* same for ssh2 */ |
1e3b8b07 | 216 | u_char *session_id2 = NULL; |
a27002e5 | 217 | u_int session_id2_len = 0; |
a306f2dd | 218 | |
c345cf9d | 219 | /* record remote hostname or ip */ |
1e3b8b07 | 220 | u_int utmp_len = MAXHOSTNAMELEN; |
c345cf9d | 221 | |
7ace8c3b | 222 | /* options.max_startup sized array of fd ints */ |
223 | int *startup_pipes = NULL; | |
224 | int startup_pipe; /* in child */ | |
225 | ||
1853d1ef | 226 | /* variables used for privilege separation */ |
d231781a | 227 | int use_privsep = -1; |
a9b33b95 | 228 | struct monitor *pmonitor = NULL; |
1853d1ef | 229 | |
2362db19 | 230 | /* global authentication context */ |
231 | Authctxt *the_authctxt = NULL; | |
232 | ||
d231781a | 233 | /* sshd_config buffer */ |
234 | Buffer cfg; | |
235 | ||
be2ca0c9 | 236 | /* message to be displayed after login */ |
237 | Buffer loginmsg; | |
238 | ||
7368a6c8 | 239 | /* Prototypes for various functions defined later in this file. */ |
396c147e | 240 | void destroy_sensitive_data(void); |
1853d1ef | 241 | void demote_sensitive_data(void); |
c8d54615 | 242 | |
396c147e | 243 | static void do_ssh1_kex(void); |
244 | static void do_ssh2_kex(void); | |
94ec8c6b | 245 | |
48e671d5 | 246 | /* |
247 | * Close all listening sockets | |
248 | */ | |
396c147e | 249 | static void |
48e671d5 | 250 | close_listen_socks(void) |
251 | { | |
252 | int i; | |
e424e241 | 253 | |
48e671d5 | 254 | for (i = 0; i < num_listen_socks; i++) |
255 | close(listen_socks[i]); | |
256 | num_listen_socks = -1; | |
257 | } | |
258 | ||
7ace8c3b | 259 | static void |
260 | close_startup_pipes(void) | |
261 | { | |
262 | int i; | |
e424e241 | 263 | |
7ace8c3b | 264 | if (startup_pipes) |
265 | for (i = 0; i < options.max_startups; i++) | |
266 | if (startup_pipes[i] != -1) | |
267 | close(startup_pipes[i]); | |
268 | } | |
269 | ||
5260325f | 270 | /* |
271 | * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP; | |
272 | * the effect is to reread the configuration file (and to regenerate | |
273 | * the server key). | |
274 | */ | |
3efa8ea9 | 275 | |
276 | /*ARGSUSED*/ | |
396c147e | 277 | static void |
5260325f | 278 | sighup_handler(int sig) |
8efc0c15 | 279 | { |
6056eb35 | 280 | int save_errno = errno; |
281 | ||
5260325f | 282 | received_sighup = 1; |
283 | signal(SIGHUP, sighup_handler); | |
6056eb35 | 284 | errno = save_errno; |
8efc0c15 | 285 | } |
286 | ||
5260325f | 287 | /* |
288 | * Called from the main program after receiving SIGHUP. | |
289 | * Restarts the server. | |
290 | */ | |
396c147e | 291 | static void |
5ca51e19 | 292 | sighup_restart(void) |
8efc0c15 | 293 | { |
bbe88b6d | 294 | logit("Received SIGHUP; restarting."); |
48e671d5 | 295 | close_listen_socks(); |
7ace8c3b | 296 | close_startup_pipes(); |
5260325f | 297 | execv(saved_argv[0], saved_argv); |
bbe88b6d | 298 | logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0], |
e424e241 | 299 | strerror(errno)); |
5260325f | 300 | exit(1); |
8efc0c15 | 301 | } |
302 | ||
5260325f | 303 | /* |
304 | * Generic signal handler for terminating signals in the master daemon. | |
5260325f | 305 | */ |
3efa8ea9 | 306 | /*ARGSUSED*/ |
396c147e | 307 | static void |
5260325f | 308 | sigterm_handler(int sig) |
8efc0c15 | 309 | { |
c9130033 | 310 | received_sigterm = sig; |
8efc0c15 | 311 | } |
312 | ||
5260325f | 313 | /* |
314 | * SIGCHLD handler. This is called whenever a child dies. This will then | |
c9130033 | 315 | * reap any zombies left by exited children. |
5260325f | 316 | */ |
3efa8ea9 | 317 | /*ARGSUSED*/ |
396c147e | 318 | static void |
5260325f | 319 | main_sigchld_handler(int sig) |
8efc0c15 | 320 | { |
5260325f | 321 | int save_errno = errno; |
e424e241 | 322 | pid_t pid; |
5260325f | 323 | int status; |
5ad13cd7 | 324 | |
8c38e88b | 325 | while ((pid = waitpid(-1, &status, WNOHANG)) > 0 || |
326 | (pid < 0 && errno == EINTR)) | |
5260325f | 327 | ; |
5ad13cd7 | 328 | |
5260325f | 329 | signal(SIGCHLD, main_sigchld_handler); |
330 | errno = save_errno; | |
8efc0c15 | 331 | } |
332 | ||
5260325f | 333 | /* |
334 | * Signal handler for the alarm after the login grace period has expired. | |
335 | */ | |
3efa8ea9 | 336 | /*ARGSUSED*/ |
396c147e | 337 | static void |
5260325f | 338 | grace_alarm_handler(int sig) |
8efc0c15 | 339 | { |
c9130033 | 340 | /* XXX no idea how fix this signal handler */ |
341 | ||
a9b33b95 | 342 | if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0) |
343 | kill(pmonitor->m_pid, SIGALRM); | |
344 | ||
5260325f | 345 | /* Log error and exit. */ |
26b9a3d2 | 346 | fatal("Timeout before authentication for %s", get_remote_ipaddr()); |
5260325f | 347 | } |
8efc0c15 | 348 | |
5260325f | 349 | /* |
350 | * Signal handler for the key regeneration alarm. Note that this | |
351 | * alarm only occurs in the daemon waiting for connections, and it does not | |
352 | * do anything with the private key or random state before forking. | |
353 | * Thus there should be no concurrency control/asynchronous execution | |
354 | * problems. | |
355 | */ | |
396c147e | 356 | static void |
cb7bd922 | 357 | generate_ephemeral_server_key(void) |
fa08c86b | 358 | { |
7fdc56c5 | 359 | u_int32_t rnd = 0; |
00be5382 | 360 | int i; |
361 | ||
cd332296 | 362 | verbose("Generating %s%d bit RSA key.", |
76ca7b01 | 363 | sensitive_data.server_key ? "new " : "", options.server_key_bits); |
fa08c86b | 364 | if (sensitive_data.server_key != NULL) |
365 | key_free(sensitive_data.server_key); | |
cd332296 | 366 | sensitive_data.server_key = key_generate(KEY_RSA1, |
76ca7b01 | 367 | options.server_key_bits); |
368 | verbose("RSA key generation complete."); | |
00be5382 | 369 | |
370 | for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) { | |
371 | if (i % 4 == 0) | |
7fdc56c5 | 372 | rnd = arc4random(); |
373 | sensitive_data.ssh1_cookie[i] = rnd & 0xff; | |
374 | rnd >>= 8; | |
00be5382 | 375 | } |
376 | arc4random_stir(); | |
fa08c86b | 377 | } |
f546c780 | 378 | |
3efa8ea9 | 379 | /*ARGSUSED*/ |
396c147e | 380 | static void |
5260325f | 381 | key_regeneration_alarm(int sig) |
382 | { | |
383 | int save_errno = errno; | |
e424e241 | 384 | |
59c97189 | 385 | signal(SIGALRM, SIG_DFL); |
5260325f | 386 | errno = save_errno; |
59c97189 | 387 | key_do_regen = 1; |
5260325f | 388 | } |
8efc0c15 | 389 | |
396c147e | 390 | static void |
7368a6c8 | 391 | sshd_exchange_identification(int sock_in, int sock_out) |
392 | { | |
2ceb8101 | 393 | u_int i; |
394 | int mismatch; | |
7368a6c8 | 395 | int remote_major, remote_minor; |
a8be9f80 | 396 | int major, minor; |
7368a6c8 | 397 | char *s; |
398 | char buf[256]; /* Must not be larger than remote_version. */ | |
399 | char remote_version[256]; /* Must be at least as big as buf. */ | |
400 | ||
a8be9f80 | 401 | if ((options.protocol & SSH_PROTO_1) && |
402 | (options.protocol & SSH_PROTO_2)) { | |
403 | major = PROTOCOL_MAJOR_1; | |
404 | minor = 99; | |
405 | } else if (options.protocol & SSH_PROTO_2) { | |
406 | major = PROTOCOL_MAJOR_2; | |
407 | minor = PROTOCOL_MINOR_2; | |
408 | } else { | |
409 | major = PROTOCOL_MAJOR_1; | |
410 | minor = PROTOCOL_MINOR_1; | |
411 | } | |
412 | snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", major, minor, SSH_VERSION); | |
7368a6c8 | 413 | server_version_string = xstrdup(buf); |
414 | ||
7b390973 | 415 | /* Send our protocol version identification. */ |
416 | if (atomicio(vwrite, sock_out, server_version_string, | |
417 | strlen(server_version_string)) | |
418 | != strlen(server_version_string)) { | |
419 | logit("Could not write ident string to %s", get_remote_ipaddr()); | |
2362db19 | 420 | cleanup_exit(255); |
7b390973 | 421 | } |
422 | ||
423 | /* Read other sides version identification. */ | |
424 | memset(buf, 0, sizeof(buf)); | |
425 | for (i = 0; i < sizeof(buf) - 1; i++) { | |
426 | if (atomicio(read, sock_in, &buf[i], 1) != 1) { | |
427 | logit("Did not receive identification string from %s", | |
428 | get_remote_ipaddr()); | |
2362db19 | 429 | cleanup_exit(255); |
7368a6c8 | 430 | } |
7b390973 | 431 | if (buf[i] == '\r') { |
432 | buf[i] = 0; | |
433 | /* Kludge for F-Secure Macintosh < 1.0.2 */ | |
434 | if (i == 12 && | |
435 | strncmp(buf, "SSH-1.5-W1.0", 12) == 0) | |
7368a6c8 | 436 | break; |
7b390973 | 437 | continue; |
438 | } | |
439 | if (buf[i] == '\n') { | |
440 | buf[i] = 0; | |
441 | break; | |
7368a6c8 | 442 | } |
7368a6c8 | 443 | } |
7b390973 | 444 | buf[sizeof(buf) - 1] = 0; |
445 | client_version_string = xstrdup(buf); | |
7368a6c8 | 446 | |
447 | /* | |
448 | * Check that the versions match. In future this might accept | |
449 | * several versions and set appropriate flags to handle them. | |
450 | */ | |
451 | if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n", | |
452 | &remote_major, &remote_minor, remote_version) != 3) { | |
6ae2364d | 453 | s = "Protocol mismatch.\n"; |
dc54438a | 454 | (void) atomicio(vwrite, sock_out, s, strlen(s)); |
7368a6c8 | 455 | close(sock_in); |
456 | close(sock_out); | |
bbe88b6d | 457 | logit("Bad protocol version identification '%.100s' from %s", |
7368a6c8 | 458 | client_version_string, get_remote_ipaddr()); |
2362db19 | 459 | cleanup_exit(255); |
7368a6c8 | 460 | } |
461 | debug("Client protocol version %d.%d; client software version %.100s", | |
184eed6a | 462 | remote_major, remote_minor, remote_version); |
7368a6c8 | 463 | |
e78a59f5 | 464 | compat_datafellows(remote_version); |
465 | ||
9a87e2ac | 466 | if (datafellows & SSH_BUG_PROBE) { |
bbe88b6d | 467 | logit("probed from %s with %s. Don't panic.", |
9a87e2ac | 468 | get_remote_ipaddr(), client_version_string); |
2362db19 | 469 | cleanup_exit(255); |
9a87e2ac | 470 | } |
471 | ||
3a1c54d4 | 472 | if (datafellows & SSH_BUG_SCANNER) { |
bbe88b6d | 473 | logit("scanned from %s with %s. Don't panic.", |
3a1c54d4 | 474 | get_remote_ipaddr(), client_version_string); |
2362db19 | 475 | cleanup_exit(255); |
3a1c54d4 | 476 | } |
477 | ||
a8be9f80 | 478 | mismatch = 0; |
6aacefa7 | 479 | switch (remote_major) { |
7368a6c8 | 480 | case 1: |
a306f2dd | 481 | if (remote_minor == 99) { |
482 | if (options.protocol & SSH_PROTO_2) | |
483 | enable_compat20(); | |
484 | else | |
485 | mismatch = 1; | |
486 | break; | |
487 | } | |
a8be9f80 | 488 | if (!(options.protocol & SSH_PROTO_1)) { |
489 | mismatch = 1; | |
490 | break; | |
491 | } | |
7368a6c8 | 492 | if (remote_minor < 3) { |
089fbbd2 | 493 | packet_disconnect("Your ssh version is too old and " |
7368a6c8 | 494 | "is no longer supported. Please install a newer version."); |
495 | } else if (remote_minor == 3) { | |
496 | /* note that this disables agent-forwarding */ | |
497 | enable_compat13(); | |
498 | } | |
a8be9f80 | 499 | break; |
e78a59f5 | 500 | case 2: |
a8be9f80 | 501 | if (options.protocol & SSH_PROTO_2) { |
e78a59f5 | 502 | enable_compat20(); |
503 | break; | |
504 | } | |
505 | /* FALLTHROUGH */ | |
6ae2364d | 506 | default: |
a8be9f80 | 507 | mismatch = 1; |
508 | break; | |
509 | } | |
510 | chop(server_version_string); | |
a8be9f80 | 511 | debug("Local version string %.200s", server_version_string); |
512 | ||
513 | if (mismatch) { | |
7368a6c8 | 514 | s = "Protocol major versions differ.\n"; |
dc54438a | 515 | (void) atomicio(vwrite, sock_out, s, strlen(s)); |
7368a6c8 | 516 | close(sock_in); |
517 | close(sock_out); | |
bbe88b6d | 518 | logit("Protocol major versions differ for %s: %.200s vs. %.200s", |
a8be9f80 | 519 | get_remote_ipaddr(), |
520 | server_version_string, client_version_string); | |
2362db19 | 521 | cleanup_exit(255); |
7368a6c8 | 522 | } |
a306f2dd | 523 | } |
524 | ||
fa08c86b | 525 | /* Destroy the host and server keys. They will no longer be needed. */ |
a306f2dd | 526 | void |
527 | destroy_sensitive_data(void) | |
528 | { | |
fa08c86b | 529 | int i; |
530 | ||
531 | if (sensitive_data.server_key) { | |
532 | key_free(sensitive_data.server_key); | |
533 | sensitive_data.server_key = NULL; | |
534 | } | |
184eed6a | 535 | for (i = 0; i < options.num_host_key_files; i++) { |
fa08c86b | 536 | if (sensitive_data.host_keys[i]) { |
537 | key_free(sensitive_data.host_keys[i]); | |
538 | sensitive_data.host_keys[i] = NULL; | |
539 | } | |
540 | } | |
541 | sensitive_data.ssh1_host_key = NULL; | |
00be5382 | 542 | memset(sensitive_data.ssh1_cookie, 0, SSH_SESSION_KEY_LENGTH); |
fa08c86b | 543 | } |
fa08c86b | 544 | |
1853d1ef | 545 | /* Demote private to public keys for network child */ |
546 | void | |
547 | demote_sensitive_data(void) | |
548 | { | |
549 | Key *tmp; | |
550 | int i; | |
551 | ||
552 | if (sensitive_data.server_key) { | |
553 | tmp = key_demote(sensitive_data.server_key); | |
554 | key_free(sensitive_data.server_key); | |
555 | sensitive_data.server_key = tmp; | |
556 | } | |
557 | ||
558 | for (i = 0; i < options.num_host_key_files; i++) { | |
559 | if (sensitive_data.host_keys[i]) { | |
560 | tmp = key_demote(sensitive_data.host_keys[i]); | |
561 | key_free(sensitive_data.host_keys[i]); | |
562 | sensitive_data.host_keys[i] = tmp; | |
563 | if (tmp->type == KEY_RSA1) | |
564 | sensitive_data.ssh1_host_key = tmp; | |
565 | } | |
566 | } | |
567 | ||
568 | /* We do not clear ssh1_host key and cookie. XXX - Okay Niels? */ | |
569 | } | |
570 | ||
51aeb639 | 571 | static void |
1853d1ef | 572 | privsep_preauth_child(void) |
573 | { | |
7fdc56c5 | 574 | u_int32_t rnd[256]; |
6ded293b | 575 | gid_t gidset[1]; |
2ea6de2b | 576 | struct passwd *pw; |
e424e241 | 577 | int i; |
1853d1ef | 578 | |
579 | /* Enable challenge-response authentication for privilege separation */ | |
580 | privsep_challenge_enable(); | |
581 | ||
582 | for (i = 0; i < 256; i++) | |
7fdc56c5 | 583 | rnd[i] = arc4random(); |
584 | RAND_seed(rnd, sizeof(rnd)); | |
1853d1ef | 585 | |
586 | /* Demote the private keys to public keys. */ | |
587 | demote_sensitive_data(); | |
588 | ||
2ea6de2b | 589 | if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) |
cdc4fc39 | 590 | fatal("Privilege separation user %s does not exist", |
591 | SSH_PRIVSEP_USER); | |
2ea6de2b | 592 | memset(pw->pw_passwd, 0, strlen(pw->pw_passwd)); |
593 | endpwent(); | |
594 | ||
343288b8 | 595 | /* Change our root directory */ |
1c352e97 | 596 | if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1) |
597 | fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR, | |
598 | strerror(errno)); | |
1853d1ef | 599 | if (chdir("/") == -1) |
edfb66cb | 600 | fatal("chdir(\"/\"): %s", strerror(errno)); |
762715ce | 601 | |
1853d1ef | 602 | /* Drop our privileges */ |
2ea6de2b | 603 | debug3("privsep user:group %u:%u", (u_int)pw->pw_uid, |
604 | (u_int)pw->pw_gid); | |
87809a1f | 605 | #if 0 |
6ff58a4b | 606 | /* XXX not ready, too heavy after chroot */ |
2ea6de2b | 607 | do_setusercontext(pw); |
87809a1f | 608 | #else |
609 | gidset[0] = pw->pw_gid; | |
87809a1f | 610 | if (setgroups(1, gidset) < 0) |
611 | fatal("setgroups: %.100s", strerror(errno)); | |
612 | permanently_set_uid(pw); | |
613 | #endif | |
1853d1ef | 614 | } |
615 | ||
2362db19 | 616 | static int |
617 | privsep_preauth(Authctxt *authctxt) | |
1853d1ef | 618 | { |
1853d1ef | 619 | int status; |
324bf712 | 620 | pid_t pid; |
1853d1ef | 621 | |
324bf712 | 622 | /* Set up unprivileged child process to deal with network data */ |
b5a28cbc | 623 | pmonitor = monitor_init(); |
324bf712 | 624 | /* Store a pointer to the kex for later rekeying */ |
b5a28cbc | 625 | pmonitor->m_pkex = &xxx_kex; |
324bf712 | 626 | |
627 | pid = fork(); | |
628 | if (pid == -1) { | |
629 | fatal("fork of unprivileged child failed"); | |
630 | } else if (pid != 0) { | |
c457707e | 631 | debug2("Network child is on pid %ld", (long)pid); |
324bf712 | 632 | |
b5a28cbc | 633 | close(pmonitor->m_recvfd); |
a9b33b95 | 634 | pmonitor->m_pid = pid; |
2362db19 | 635 | monitor_child_preauth(authctxt, pmonitor); |
b5a28cbc | 636 | close(pmonitor->m_sendfd); |
324bf712 | 637 | |
638 | /* Sync memory */ | |
b5a28cbc | 639 | monitor_sync(pmonitor); |
324bf712 | 640 | |
641 | /* Wait for the child's exit status */ | |
8c38e88b | 642 | while (waitpid(pid, &status, 0) < 0) |
643 | if (errno != EINTR) | |
644 | break; | |
2362db19 | 645 | return (1); |
324bf712 | 646 | } else { |
647 | /* child */ | |
648 | ||
b5a28cbc | 649 | close(pmonitor->m_sendfd); |
324bf712 | 650 | |
651 | /* Demote the child */ | |
652 | if (getuid() == 0 || geteuid() == 0) | |
653 | privsep_preauth_child(); | |
47c36e5b | 654 | setproctitle("%s", "[net]"); |
324bf712 | 655 | } |
2362db19 | 656 | return (0); |
324bf712 | 657 | } |
658 | ||
659 | static void | |
660 | privsep_postauth(Authctxt *authctxt) | |
661 | { | |
94d8258b | 662 | #ifdef DISABLE_FD_PASSING |
d170feb1 | 663 | if (1) { |
664 | #else | |
1853d1ef | 665 | if (authctxt->pw->pw_uid == 0 || options.use_login) { |
d170feb1 | 666 | #endif |
1853d1ef | 667 | /* File descriptor passing is broken or root login */ |
1853d1ef | 668 | use_privsep = 0; |
ae25711b | 669 | goto skip; |
1853d1ef | 670 | } |
762715ce | 671 | |
1853d1ef | 672 | /* New socket pair */ |
b5a28cbc | 673 | monitor_reinit(pmonitor); |
1853d1ef | 674 | |
b5a28cbc | 675 | pmonitor->m_pid = fork(); |
676 | if (pmonitor->m_pid == -1) | |
1853d1ef | 677 | fatal("fork of unprivileged child failed"); |
b5a28cbc | 678 | else if (pmonitor->m_pid != 0) { |
c457707e | 679 | debug2("User child is on pid %ld", (long)pmonitor->m_pid); |
b5a28cbc | 680 | close(pmonitor->m_recvfd); |
f143ed33 | 681 | buffer_clear(&loginmsg); |
b5a28cbc | 682 | monitor_child_postauth(pmonitor); |
1853d1ef | 683 | |
684 | /* NEVERREACHED */ | |
685 | exit(0); | |
686 | } | |
687 | ||
b5a28cbc | 688 | close(pmonitor->m_sendfd); |
1853d1ef | 689 | |
690 | /* Demote the private keys to public keys. */ | |
691 | demote_sensitive_data(); | |
692 | ||
693 | /* Drop privileges */ | |
694 | do_setusercontext(authctxt->pw); | |
695 | ||
ae25711b | 696 | skip: |
1853d1ef | 697 | /* It is safe now to apply the key state */ |
b5a28cbc | 698 | monitor_apply_keystate(pmonitor); |
07200973 | 699 | |
700 | /* | |
701 | * Tell the packet layer that authentication was successful, since | |
702 | * this information is not part of the key state. | |
703 | */ | |
704 | packet_set_authenticated(); | |
1853d1ef | 705 | } |
706 | ||
396c147e | 707 | static char * |
fa08c86b | 708 | list_hostkey_types(void) |
709 | { | |
3469eac4 | 710 | Buffer b; |
b6c7b7b7 | 711 | const char *p; |
712 | char *ret; | |
fa08c86b | 713 | int i; |
3469eac4 | 714 | |
715 | buffer_init(&b); | |
184eed6a | 716 | for (i = 0; i < options.num_host_key_files; i++) { |
fa08c86b | 717 | Key *key = sensitive_data.host_keys[i]; |
718 | if (key == NULL) | |
719 | continue; | |
6aacefa7 | 720 | switch (key->type) { |
fa08c86b | 721 | case KEY_RSA: |
722 | case KEY_DSA: | |
3469eac4 | 723 | if (buffer_len(&b) > 0) |
724 | buffer_append(&b, ",", 1); | |
725 | p = key_ssh_name(key); | |
726 | buffer_append(&b, p, strlen(p)); | |
fa08c86b | 727 | break; |
728 | } | |
729 | } | |
3469eac4 | 730 | buffer_append(&b, "\0", 1); |
b6c7b7b7 | 731 | ret = xstrdup(buffer_ptr(&b)); |
3469eac4 | 732 | buffer_free(&b); |
b6c7b7b7 | 733 | debug("list_hostkey_types: %s", ret); |
734 | return ret; | |
fa08c86b | 735 | } |
736 | ||
1853d1ef | 737 | Key * |
fa08c86b | 738 | get_hostkey_by_type(int type) |
739 | { | |
740 | int i; | |
e424e241 | 741 | |
184eed6a | 742 | for (i = 0; i < options.num_host_key_files; i++) { |
fa08c86b | 743 | Key *key = sensitive_data.host_keys[i]; |
744 | if (key != NULL && key->type == type) | |
745 | return key; | |
746 | } | |
747 | return NULL; | |
7368a6c8 | 748 | } |
749 | ||
1853d1ef | 750 | Key * |
751 | get_hostkey_by_index(int ind) | |
752 | { | |
753 | if (ind < 0 || ind >= options.num_host_key_files) | |
754 | return (NULL); | |
755 | return (sensitive_data.host_keys[ind]); | |
756 | } | |
757 | ||
758 | int | |
759 | get_hostkey_index(Key *key) | |
760 | { | |
761 | int i; | |
e424e241 | 762 | |
1853d1ef | 763 | for (i = 0; i < options.num_host_key_files; i++) { |
764 | if (key == sensitive_data.host_keys[i]) | |
765 | return (i); | |
766 | } | |
767 | return (-1); | |
768 | } | |
769 | ||
c345cf9d | 770 | /* |
771 | * returns 1 if connection should be dropped, 0 otherwise. | |
772 | * dropping starts at connection #max_startups_begin with a probability | |
773 | * of (max_startups_rate/100). the probability increases linearly until | |
774 | * all connections are dropped for startups > max_startups | |
775 | */ | |
396c147e | 776 | static int |
c345cf9d | 777 | drop_connection(int startups) |
778 | { | |
1c5eab6f | 779 | int p, r; |
c345cf9d | 780 | |
781 | if (startups < options.max_startups_begin) | |
782 | return 0; | |
783 | if (startups >= options.max_startups) | |
784 | return 1; | |
785 | if (options.max_startups_rate == 100) | |
786 | return 1; | |
787 | ||
788 | p = 100 - options.max_startups_rate; | |
789 | p *= startups - options.max_startups_begin; | |
1c5eab6f | 790 | p /= options.max_startups - options.max_startups_begin; |
c345cf9d | 791 | p += options.max_startups_rate; |
1c5eab6f | 792 | r = arc4random() % 100; |
c345cf9d | 793 | |
e9aec1d4 | 794 | debug("drop_connection: p %d, r %d", p, r); |
c345cf9d | 795 | return (r < p) ? 1 : 0; |
796 | } | |
797 | ||
2717fa0f | 798 | static void |
799 | usage(void) | |
800 | { | |
85ac7a84 | 801 | fprintf(stderr, "%s, %s\n", |
4526e8c2 | 802 | SSH_RELEASE, SSLeay_version(SSLEAY_VERSION)); |
65edde94 | 803 | fprintf(stderr, |
804 | "usage: sshd [-46Ddeiqt] [-b bits] [-f config_file] [-g login_grace_time]\n" | |
805 | " [-h host_key_file] [-k key_gen_time] [-o option] [-p port] [-u len]\n" | |
806 | ); | |
2717fa0f | 807 | exit(1); |
808 | } | |
809 | ||
b9a549d7 | 810 | static void |
811 | send_rexec_state(int fd, Buffer *conf) | |
812 | { | |
813 | Buffer m; | |
814 | ||
815 | debug3("%s: entering fd = %d config len %d", __func__, fd, | |
816 | buffer_len(conf)); | |
817 | ||
818 | /* | |
819 | * Protocol from reexec master to child: | |
820 | * string configuration | |
821 | * u_int ephemeral_key_follows | |
822 | * bignum e (only if ephemeral_key_follows == 1) | |
823 | * bignum n " | |
824 | * bignum d " | |
825 | * bignum iqmp " | |
826 | * bignum p " | |
827 | * bignum q " | |
72f02ae7 | 828 | * string rngseed (only if OpenSSL is not self-seeded) |
b9a549d7 | 829 | */ |
830 | buffer_init(&m); | |
831 | buffer_put_cstring(&m, buffer_ptr(conf)); | |
832 | ||
f2107e97 | 833 | if (sensitive_data.server_key != NULL && |
b9a549d7 | 834 | sensitive_data.server_key->type == KEY_RSA1) { |
835 | buffer_put_int(&m, 1); | |
836 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->e); | |
837 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->n); | |
838 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->d); | |
839 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->iqmp); | |
840 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->p); | |
841 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->q); | |
842 | } else | |
843 | buffer_put_int(&m, 0); | |
844 | ||
72f02ae7 | 845 | #ifndef OPENSSL_PRNG_ONLY |
846 | rexec_send_rng_seed(&m); | |
847 | #endif | |
848 | ||
b9a549d7 | 849 | if (ssh_msg_send(fd, 0, &m) == -1) |
850 | fatal("%s: ssh_msg_send failed", __func__); | |
851 | ||
852 | buffer_free(&m); | |
853 | ||
854 | debug3("%s: done", __func__); | |
855 | } | |
856 | ||
857 | static void | |
858 | recv_rexec_state(int fd, Buffer *conf) | |
859 | { | |
860 | Buffer m; | |
861 | char *cp; | |
862 | u_int len; | |
863 | ||
864 | debug3("%s: entering fd = %d", __func__, fd); | |
865 | ||
866 | buffer_init(&m); | |
867 | ||
868 | if (ssh_msg_recv(fd, &m) == -1) | |
869 | fatal("%s: ssh_msg_recv failed", __func__); | |
870 | if (buffer_get_char(&m) != 0) | |
871 | fatal("%s: rexec version mismatch", __func__); | |
872 | ||
873 | cp = buffer_get_string(&m, &len); | |
874 | if (conf != NULL) | |
875 | buffer_append(conf, cp, len + 1); | |
876 | xfree(cp); | |
877 | ||
878 | if (buffer_get_int(&m)) { | |
879 | if (sensitive_data.server_key != NULL) | |
880 | key_free(sensitive_data.server_key); | |
881 | sensitive_data.server_key = key_new_private(KEY_RSA1); | |
882 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->e); | |
883 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->n); | |
884 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->d); | |
885 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->iqmp); | |
886 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->p); | |
887 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->q); | |
888 | rsa_generate_additional_parameters( | |
889 | sensitive_data.server_key->rsa); | |
890 | } | |
72f02ae7 | 891 | |
892 | #ifndef OPENSSL_PRNG_ONLY | |
893 | rexec_recv_rng_seed(&m); | |
894 | #endif | |
895 | ||
b9a549d7 | 896 | buffer_free(&m); |
897 | ||
898 | debug3("%s: done", __func__); | |
899 | } | |
900 | ||
5260325f | 901 | /* |
902 | * Main program for the daemon. | |
903 | */ | |
8efc0c15 | 904 | int |
905 | main(int ac, char **av) | |
906 | { | |
5260325f | 907 | extern char *optarg; |
908 | extern int optind; | |
52e3daed | 909 | int opt, j, i, on = 1; |
83529a6b | 910 | int sock_in = -1, sock_out = -1, newsock = -1; |
9da5c3c9 | 911 | pid_t pid; |
48e671d5 | 912 | socklen_t fromlen; |
48e671d5 | 913 | fd_set *fdset; |
914 | struct sockaddr_storage from; | |
5260325f | 915 | const char *remote_ip; |
916 | int remote_port; | |
5260325f | 917 | FILE *f; |
48e671d5 | 918 | struct addrinfo *ai; |
919 | char ntop[NI_MAXHOST], strport[NI_MAXSERV]; | |
c5894280 | 920 | char *line; |
48e671d5 | 921 | int listen_sock, maxfd; |
9216f89c | 922 | int startup_p[2] = { -1 , -1 }, config_s[2] = { -1 , -1 }; |
089fbbd2 | 923 | int startups = 0; |
aeaa3d9e | 924 | Key *key; |
2362db19 | 925 | Authctxt *authctxt; |
59c97189 | 926 | int ret, key_used = 0; |
5260325f | 927 | |
6e879cb4 | 928 | #ifdef HAVE_SECUREWARE |
929 | (void)set_auth_parameters(ac, av); | |
930 | #endif | |
fda04d7d | 931 | __progname = ssh_get_progname(av[0]); |
264dce47 | 932 | init_rng(); |
933 | ||
d0104542 | 934 | /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */ |
4d33e531 | 935 | saved_argc = ac; |
7706b4c7 | 936 | rexec_argc = ac; |
01d35895 | 937 | saved_argv = xcalloc(ac + 1, sizeof(*saved_argv)); |
d0104542 | 938 | for (i = 0; i < ac; i++) |
939 | saved_argv[i] = xstrdup(av[i]); | |
f420d2ba | 940 | saved_argv[i] = NULL; |
d0104542 | 941 | |
942 | #ifndef HAVE_SETPROCTITLE | |
943 | /* Prepare for later setproctitle emulation */ | |
944 | compat_init_setproctitle(ac, av); | |
416c732d | 945 | av = saved_argv; |
d0104542 | 946 | #endif |
5260325f | 947 | |
a4c0faa2 | 948 | if (geteuid() == 0 && setgroups(0, NULL) == -1) |
949 | debug("setgroups(): %.200s", strerror(errno)); | |
950 | ||
fd6168c1 | 951 | /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ |
952 | sanitise_stdfd(); | |
953 | ||
5260325f | 954 | /* Initialize configuration options to their default values. */ |
955 | initialize_server_options(&options); | |
956 | ||
957 | /* Parse command-line arguments. */ | |
b9a549d7 | 958 | while ((opt = getopt(ac, av, "f:p:b:k:h:g:u:o:dDeiqrtQR46")) != -1) { |
5260325f | 959 | switch (opt) { |
48e671d5 | 960 | case '4': |
31b41ceb | 961 | options.address_family = AF_INET; |
48e671d5 | 962 | break; |
963 | case '6': | |
31b41ceb | 964 | options.address_family = AF_INET6; |
48e671d5 | 965 | break; |
5260325f | 966 | case 'f': |
967 | config_file_name = optarg; | |
968 | break; | |
969 | case 'd': | |
e053cd2c | 970 | if (debug_flag == 0) { |
bcbf86ec | 971 | debug_flag = 1; |
972 | options.log_level = SYSLOG_LEVEL_DEBUG1; | |
e053cd2c | 973 | } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) |
bcbf86ec | 974 | options.log_level++; |
5260325f | 975 | break; |
0b6fbf03 | 976 | case 'D': |
977 | no_daemon_flag = 1; | |
978 | break; | |
ff14faf1 | 979 | case 'e': |
980 | log_stderr = 1; | |
981 | break; | |
5260325f | 982 | case 'i': |
983 | inetd_flag = 1; | |
984 | break; | |
b9a549d7 | 985 | case 'r': |
986 | rexec_flag = 0; | |
987 | break; | |
988 | case 'R': | |
989 | rexeced_flag = 1; | |
990 | inetd_flag = 1; | |
991 | break; | |
5260325f | 992 | case 'Q': |
9bd5b720 | 993 | /* ignored */ |
5260325f | 994 | break; |
995 | case 'q': | |
996 | options.log_level = SYSLOG_LEVEL_QUIET; | |
997 | break; | |
998 | case 'b': | |
3efa8ea9 | 999 | options.server_key_bits = (int)strtonum(optarg, 256, |
1000 | 32768, NULL); | |
5260325f | 1001 | break; |
1002 | case 'p': | |
48e671d5 | 1003 | options.ports_from_cmdline = 1; |
bcbf86ec | 1004 | if (options.num_ports >= MAX_PORTS) { |
1005 | fprintf(stderr, "too many ports.\n"); | |
1006 | exit(1); | |
1007 | } | |
2d2a2c65 | 1008 | options.ports[options.num_ports++] = a2port(optarg); |
1009 | if (options.ports[options.num_ports-1] == 0) { | |
1010 | fprintf(stderr, "Bad port number.\n"); | |
1011 | exit(1); | |
1012 | } | |
5260325f | 1013 | break; |
1014 | case 'g': | |
e2b1fb42 | 1015 | if ((options.login_grace_time = convtime(optarg)) == -1) { |
1016 | fprintf(stderr, "Invalid login grace time.\n"); | |
1017 | exit(1); | |
1018 | } | |
5260325f | 1019 | break; |
1020 | case 'k': | |
e2b1fb42 | 1021 | if ((options.key_regeneration_time = convtime(optarg)) == -1) { |
1022 | fprintf(stderr, "Invalid key regeneration interval.\n"); | |
1023 | exit(1); | |
1024 | } | |
5260325f | 1025 | break; |
1026 | case 'h': | |
fa08c86b | 1027 | if (options.num_host_key_files >= MAX_HOSTKEYS) { |
1028 | fprintf(stderr, "too many host keys.\n"); | |
1029 | exit(1); | |
1030 | } | |
1031 | options.host_key_files[options.num_host_key_files++] = optarg; | |
5260325f | 1032 | break; |
f87f09aa | 1033 | case 't': |
1034 | test_flag = 1; | |
1035 | break; | |
c345cf9d | 1036 | case 'u': |
3efa8ea9 | 1037 | utmp_len = (u_int)strtonum(optarg, 0, MAXHOSTNAMELEN+1, NULL); |
67f04db1 | 1038 | if (utmp_len > MAXHOSTNAMELEN) { |
1039 | fprintf(stderr, "Invalid utmp length.\n"); | |
1040 | exit(1); | |
1041 | } | |
c345cf9d | 1042 | break; |
2717fa0f | 1043 | case 'o': |
c5894280 | 1044 | line = xstrdup(optarg); |
1045 | if (process_server_config_line(&options, line, | |
d231781a | 1046 | "command-line", 0, NULL, NULL, NULL, NULL) != 0) |
184eed6a | 1047 | exit(1); |
c5894280 | 1048 | xfree(line); |
2717fa0f | 1049 | break; |
5260325f | 1050 | case '?': |
1051 | default: | |
2717fa0f | 1052 | usage(); |
1053 | break; | |
5260325f | 1054 | } |
1055 | } | |
b9a549d7 | 1056 | if (rexeced_flag || inetd_flag) |
1057 | rexec_flag = 0; | |
1058 | if (rexec_flag && (av[0] == NULL || *av[0] != '/')) | |
1059 | fatal("sshd re-exec requires execution with an absolute path"); | |
1060 | if (rexeced_flag) | |
b250e837 | 1061 | closefrom(REEXEC_MIN_FREE_FD); |
1062 | else | |
1063 | closefrom(REEXEC_DEVCRYPTO_RESERVED_FD); | |
b9a549d7 | 1064 | |
1a92bd7e | 1065 | SSLeay_add_all_algorithms(); |
5260325f | 1066 | |
48e671d5 | 1067 | /* |
1068 | * Force logging to stderr until we have loaded the private host | |
1069 | * key (unless started from inetd) | |
1070 | */ | |
1fe6a48f | 1071 | log_init(__progname, |
980c9344 | 1072 | options.log_level == SYSLOG_LEVEL_NOT_SET ? |
1073 | SYSLOG_LEVEL_INFO : options.log_level, | |
1074 | options.log_facility == SYSLOG_FACILITY_NOT_SET ? | |
1075 | SYSLOG_FACILITY_AUTH : options.log_facility, | |
51efad8c | 1076 | log_stderr || !inetd_flag); |
48e671d5 | 1077 | |
351f44a0 | 1078 | /* |
1079 | * Unset KRB5CCNAME, otherwise the user's session may inherit it from | |
1080 | * root's environment | |
d1cf9a87 | 1081 | */ |
3bfd27d5 | 1082 | if (getenv("KRB5CCNAME") != NULL) |
1083 | unsetenv("KRB5CCNAME"); | |
1084 | ||
ef51930f | 1085 | #ifdef _UNICOS |
e5ba4718 | 1086 | /* Cray can define user privs drop all privs now! |
1a23ac2c | 1087 | * Not needed on PRIV_SU systems! |
1088 | */ | |
1089 | drop_cray_privs(); | |
1090 | #endif | |
1091 | ||
b9a549d7 | 1092 | sensitive_data.server_key = NULL; |
1093 | sensitive_data.ssh1_host_key = NULL; | |
1094 | sensitive_data.have_ssh1_key = 0; | |
1095 | sensitive_data.have_ssh2_key = 0; | |
1096 | ||
1097 | /* Fetch our configuration */ | |
1098 | buffer_init(&cfg); | |
1099 | if (rexeced_flag) | |
b250e837 | 1100 | recv_rexec_state(REEXEC_CONFIG_PASS_FD, &cfg); |
b9a549d7 | 1101 | else |
1102 | load_server_config(config_file_name, &cfg); | |
1103 | ||
d231781a | 1104 | parse_server_config(&options, rexeced_flag ? "rexec" : config_file_name, |
1105 | &cfg, NULL, NULL, NULL); | |
5260325f | 1106 | |
72f02ae7 | 1107 | seed_rng(); |
1108 | ||
5260325f | 1109 | /* Fill in default values for those options not explicitly set. */ |
1110 | fill_default_server_options(&options); | |
1111 | ||
31b41ceb | 1112 | /* set default channel AF */ |
1113 | channel_set_af(options.address_family); | |
1114 | ||
5260325f | 1115 | /* Check that there are no remaining arguments. */ |
1116 | if (optind < ac) { | |
1117 | fprintf(stderr, "Extra argument %s.\n", av[optind]); | |
1118 | exit(1); | |
8efc0c15 | 1119 | } |
5260325f | 1120 | |
4526e8c2 | 1121 | debug("sshd version %.100s", SSH_RELEASE); |
5260325f | 1122 | |
fa08c86b | 1123 | /* load private host keys */ |
52e3daed | 1124 | sensitive_data.host_keys = xcalloc(options.num_host_key_files, |
343288b8 | 1125 | sizeof(Key *)); |
184eed6a | 1126 | for (i = 0; i < options.num_host_key_files; i++) |
1e3b8b07 | 1127 | sensitive_data.host_keys[i] = NULL; |
a306f2dd | 1128 | |
184eed6a | 1129 | for (i = 0; i < options.num_host_key_files; i++) { |
aeaa3d9e | 1130 | key = key_load_private(options.host_key_files[i], "", NULL); |
1131 | sensitive_data.host_keys[i] = key; | |
fa08c86b | 1132 | if (key == NULL) { |
58cfa257 | 1133 | error("Could not load host key: %s", |
1134 | options.host_key_files[i]); | |
aeaa3d9e | 1135 | sensitive_data.host_keys[i] = NULL; |
fa08c86b | 1136 | continue; |
a306f2dd | 1137 | } |
6aacefa7 | 1138 | switch (key->type) { |
fa08c86b | 1139 | case KEY_RSA1: |
1140 | sensitive_data.ssh1_host_key = key; | |
1141 | sensitive_data.have_ssh1_key = 1; | |
1142 | break; | |
1143 | case KEY_RSA: | |
1144 | case KEY_DSA: | |
1145 | sensitive_data.have_ssh2_key = 1; | |
1146 | break; | |
a306f2dd | 1147 | } |
aeaa3d9e | 1148 | debug("private host key: #%d type %d %s", i, key->type, |
1149 | key_type(key)); | |
fa08c86b | 1150 | } |
1151 | if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) { | |
bbe88b6d | 1152 | logit("Disabling protocol version 1. Could not load host key"); |
fa08c86b | 1153 | options.protocol &= ~SSH_PROTO_1; |
1154 | } | |
1155 | if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) { | |
bbe88b6d | 1156 | logit("Disabling protocol version 2. Could not load host key"); |
fa08c86b | 1157 | options.protocol &= ~SSH_PROTO_2; |
a306f2dd | 1158 | } |
6a416424 | 1159 | if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) { |
bbe88b6d | 1160 | logit("sshd: no hostkeys available -- exiting."); |
5260325f | 1161 | exit(1); |
1162 | } | |
5260325f | 1163 | |
a306f2dd | 1164 | /* Check certain values for sanity. */ |
1165 | if (options.protocol & SSH_PROTO_1) { | |
1166 | if (options.server_key_bits < 512 || | |
1167 | options.server_key_bits > 32768) { | |
1168 | fprintf(stderr, "Bad server key size.\n"); | |
1169 | exit(1); | |
1170 | } | |
1171 | /* | |
1172 | * Check that server and host key lengths differ sufficiently. This | |
1173 | * is necessary to make double encryption work with rsaref. Oh, I | |
1174 | * hate software patents. I dont know if this can go? Niels | |
1175 | */ | |
1176 | if (options.server_key_bits > | |
e424e241 | 1177 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) - |
1178 | SSH_KEY_BITS_RESERVED && options.server_key_bits < | |
1179 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + | |
1180 | SSH_KEY_BITS_RESERVED) { | |
a306f2dd | 1181 | options.server_key_bits = |
e424e241 | 1182 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + |
1183 | SSH_KEY_BITS_RESERVED; | |
a306f2dd | 1184 | debug("Forcing server key to %d bits to make it differ from host key.", |
1185 | options.server_key_bits); | |
1186 | } | |
1187 | } | |
1188 | ||
3cc54fbb | 1189 | if (use_privsep) { |
3cc54fbb | 1190 | struct stat st; |
1191 | ||
3efa8ea9 | 1192 | if (getpwnam(SSH_PRIVSEP_USER) == NULL) |
3cc54fbb | 1193 | fatal("Privilege separation user %s does not exist", |
1194 | SSH_PRIVSEP_USER); | |
1195 | if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) || | |
1196 | (S_ISDIR(st.st_mode) == 0)) | |
1197 | fatal("Missing privilege separation directory: %s", | |
1198 | _PATH_PRIVSEP_CHROOT_DIR); | |
b9b82dab | 1199 | |
1200 | #ifdef HAVE_CYGWIN | |
1201 | if (check_ntsec(_PATH_PRIVSEP_CHROOT_DIR) && | |
1202 | (st.st_uid != getuid () || | |
1203 | (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)) | |
1204 | #else | |
a56313d7 | 1205 | if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0) |
b9b82dab | 1206 | #endif |
5f021474 | 1207 | fatal("%s must be owned by root and not group or " |
1208 | "world-writable.", _PATH_PRIVSEP_CHROOT_DIR); | |
3cc54fbb | 1209 | } |
1210 | ||
f87f09aa | 1211 | /* Configuration looks good, so exit if in test mode. */ |
1212 | if (test_flag) | |
1213 | exit(0); | |
1214 | ||
018a5ea3 | 1215 | /* |
1216 | * Clear out any supplemental groups we may have inherited. This | |
1217 | * prevents inadvertent creation of files with bad modes (in the | |
aff51935 | 1218 | * portable version at least, it's certainly possible for PAM |
1219 | * to create a file, and we can't control the code in every | |
018a5ea3 | 1220 | * module which might be used). |
1221 | */ | |
1222 | if (setgroups(0, NULL) < 0) | |
1223 | debug("setgroups() failed: %.200s", strerror(errno)); | |
1224 | ||
b9a549d7 | 1225 | if (rexec_flag) { |
52e3daed | 1226 | rexec_argv = xcalloc(rexec_argc + 2, sizeof(char *)); |
b9a549d7 | 1227 | for (i = 0; i < rexec_argc; i++) { |
1228 | debug("rexec_argv[%d]='%s'", i, saved_argv[i]); | |
1229 | rexec_argv[i] = saved_argv[i]; | |
1230 | } | |
1231 | rexec_argv[rexec_argc] = "-R"; | |
1232 | rexec_argv[rexec_argc + 1] = NULL; | |
1233 | } | |
1234 | ||
a306f2dd | 1235 | /* Initialize the log (it is reinitialized below in case we forked). */ |
25c31d49 | 1236 | if (debug_flag && (!inetd_flag || rexeced_flag)) |
5260325f | 1237 | log_stderr = 1; |
1fe6a48f | 1238 | log_init(__progname, options.log_level, options.log_facility, log_stderr); |
5260325f | 1239 | |
a306f2dd | 1240 | /* |
1241 | * If not in debugging mode, and not started from inetd, disconnect | |
1242 | * from the controlling terminal, and fork. The original process | |
1243 | * exits. | |
1244 | */ | |
0b6fbf03 | 1245 | if (!(debug_flag || inetd_flag || no_daemon_flag)) { |
8efc0c15 | 1246 | #ifdef TIOCNOTTY |
5260325f | 1247 | int fd; |
8efc0c15 | 1248 | #endif /* TIOCNOTTY */ |
5260325f | 1249 | if (daemon(0, 0) < 0) |
1250 | fatal("daemon() failed: %.200s", strerror(errno)); | |
1251 | ||
1252 | /* Disconnect from the controlling tty. */ | |
8efc0c15 | 1253 | #ifdef TIOCNOTTY |
5ca51e19 | 1254 | fd = open(_PATH_TTY, O_RDWR | O_NOCTTY); |
5260325f | 1255 | if (fd >= 0) { |
1256 | (void) ioctl(fd, TIOCNOTTY, NULL); | |
1257 | close(fd); | |
1258 | } | |
8efc0c15 | 1259 | #endif /* TIOCNOTTY */ |
8efc0c15 | 1260 | } |
5260325f | 1261 | /* Reinitialize the log (because of the fork above). */ |
1fe6a48f | 1262 | log_init(__progname, options.log_level, options.log_facility, log_stderr); |
5260325f | 1263 | |
5260325f | 1264 | /* Initialize the random number generator. */ |
1265 | arc4random_stir(); | |
1266 | ||
1267 | /* Chdir to the root directory so that the current disk can be | |
1268 | unmounted if desired. */ | |
1269 | chdir("/"); | |
184eed6a | 1270 | |
1d3c30db | 1271 | /* ignore SIGPIPE */ |
1272 | signal(SIGPIPE, SIG_IGN); | |
5260325f | 1273 | |
5260325f | 1274 | /* Start listening for a socket, unless started from inetd. */ |
1275 | if (inetd_flag) { | |
b9a549d7 | 1276 | int fd; |
1277 | ||
4c8722d9 | 1278 | startup_pipe = -1; |
b9a549d7 | 1279 | if (rexeced_flag) { |
b250e837 | 1280 | close(REEXEC_CONFIG_PASS_FD); |
b9a549d7 | 1281 | sock_in = sock_out = dup(STDIN_FILENO); |
1282 | if (!debug_flag) { | |
b250e837 | 1283 | startup_pipe = dup(REEXEC_STARTUP_PIPE_FD); |
1284 | close(REEXEC_STARTUP_PIPE_FD); | |
b9a549d7 | 1285 | } |
1286 | } else { | |
1287 | sock_in = dup(STDIN_FILENO); | |
1288 | sock_out = dup(STDOUT_FILENO); | |
1289 | } | |
a306f2dd | 1290 | /* |
1291 | * We intentionally do not close the descriptors 0, 1, and 2 | |
b9a549d7 | 1292 | * as our code for setting the descriptors won't work if |
a306f2dd | 1293 | * ttyfd happens to be one of those. |
1294 | */ | |
b9a549d7 | 1295 | if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { |
1296 | dup2(fd, STDIN_FILENO); | |
1297 | dup2(fd, STDOUT_FILENO); | |
1298 | if (fd > STDOUT_FILENO) | |
1299 | close(fd); | |
1300 | } | |
5260325f | 1301 | debug("inetd sockets after dupping: %d, %d", sock_in, sock_out); |
b9a549d7 | 1302 | if ((options.protocol & SSH_PROTO_1) && |
1303 | sensitive_data.server_key == NULL) | |
cb7bd922 | 1304 | generate_ephemeral_server_key(); |
5260325f | 1305 | } else { |
48e671d5 | 1306 | for (ai = options.listen_addrs; ai; ai = ai->ai_next) { |
1307 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) | |
1308 | continue; | |
1309 | if (num_listen_socks >= MAX_LISTEN_SOCKS) | |
1310 | fatal("Too many listen sockets. " | |
1311 | "Enlarge MAX_LISTEN_SOCKS"); | |
945a9853 | 1312 | if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen, |
48e671d5 | 1313 | ntop, sizeof(ntop), strport, sizeof(strport), |
945a9853 | 1314 | NI_NUMERICHOST|NI_NUMERICSERV)) != 0) { |
1315 | error("getnameinfo failed: %.100s", | |
1316 | (ret != EAI_SYSTEM) ? gai_strerror(ret) : | |
1317 | strerror(errno)); | |
48e671d5 | 1318 | continue; |
1319 | } | |
1320 | /* Create socket for listening. */ | |
3e131a6d | 1321 | listen_sock = socket(ai->ai_family, ai->ai_socktype, |
1322 | ai->ai_protocol); | |
48e671d5 | 1323 | if (listen_sock < 0) { |
1324 | /* kernel may not support ipv6 */ | |
1325 | verbose("socket: %.100s", strerror(errno)); | |
1326 | continue; | |
1327 | } | |
170694d7 | 1328 | if (set_nonblock(listen_sock) == -1) { |
a666e3b1 | 1329 | close(listen_sock); |
1330 | continue; | |
1331 | } | |
48e671d5 | 1332 | /* |
facfd613 | 1333 | * Set socket options. |
1334 | * Allow local port reuse in TIME_WAIT. | |
48e671d5 | 1335 | */ |
facfd613 | 1336 | if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR, |
1337 | &on, sizeof(on)) == -1) | |
1338 | error("setsockopt SO_REUSEADDR: %s", strerror(errno)); | |
48e671d5 | 1339 | |
1340 | debug("Bind to port %s on %s.", strport, ntop); | |
1341 | ||
1342 | /* Bind the socket to the desired port. */ | |
32ced054 | 1343 | if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) { |
1344 | if (!ai->ai_next) | |
1345 | error("Bind to port %s on %s failed: %.200s.", | |
1346 | strport, ntop, strerror(errno)); | |
48e671d5 | 1347 | close(listen_sock); |
1348 | continue; | |
1349 | } | |
1350 | listen_socks[num_listen_socks] = listen_sock; | |
1351 | num_listen_socks++; | |
1352 | ||
1353 | /* Start listening on the port. */ | |
fce39749 | 1354 | if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0) |
9f513268 | 1355 | fatal("listen on [%s]:%s: %.100s", |
1356 | ntop, strport, strerror(errno)); | |
1357 | logit("Server listening on %s port %s.", ntop, strport); | |
5260325f | 1358 | } |
48e671d5 | 1359 | freeaddrinfo(options.listen_addrs); |
1360 | ||
1361 | if (!num_listen_socks) | |
1362 | fatal("Cannot bind any address."); | |
1363 | ||
3aca00a3 | 1364 | if (options.protocol & SSH_PROTO_1) |
1365 | generate_ephemeral_server_key(); | |
1366 | ||
1367 | /* | |
1368 | * Arrange to restart on SIGHUP. The handler needs | |
1369 | * listen_sock. | |
1370 | */ | |
1371 | signal(SIGHUP, sighup_handler); | |
1372 | ||
1373 | signal(SIGTERM, sigterm_handler); | |
1374 | signal(SIGQUIT, sigterm_handler); | |
1375 | ||
1376 | /* Arrange SIGCHLD to be caught. */ | |
1377 | signal(SIGCHLD, main_sigchld_handler); | |
1378 | ||
1379 | /* Write out the pid file after the sigterm handler is setup */ | |
5260325f | 1380 | if (!debug_flag) { |
aa3378df | 1381 | /* |
97fb6912 | 1382 | * Record our pid in /var/run/sshd.pid to make it |
1383 | * easier to kill the correct sshd. We don't want to | |
1384 | * do this before the bind above because the bind will | |
aa3378df | 1385 | * fail if there already is a daemon, and this will |
1386 | * overwrite any old pid in the file. | |
1387 | */ | |
3c62e7eb | 1388 | f = fopen(options.pid_file, "wb"); |
71b9ced0 | 1389 | if (f == NULL) { |
1390 | error("Couldn't create pid file \"%s\": %s", | |
1391 | options.pid_file, strerror(errno)); | |
1392 | } else { | |
c457707e | 1393 | fprintf(f, "%ld\n", (long) getpid()); |
5260325f | 1394 | fclose(f); |
1395 | } | |
8efc0c15 | 1396 | } |
5260325f | 1397 | |
48e671d5 | 1398 | /* setup fd set for listen */ |
089fbbd2 | 1399 | fdset = NULL; |
48e671d5 | 1400 | maxfd = 0; |
1401 | for (i = 0; i < num_listen_socks; i++) | |
1402 | if (listen_socks[i] > maxfd) | |
1403 | maxfd = listen_socks[i]; | |
089fbbd2 | 1404 | /* pipes connected to unauthenticated childs */ |
52e3daed | 1405 | startup_pipes = xcalloc(options.max_startups, sizeof(int)); |
089fbbd2 | 1406 | for (i = 0; i < options.max_startups; i++) |
1407 | startup_pipes[i] = -1; | |
48e671d5 | 1408 | |
aa3378df | 1409 | /* |
1410 | * Stay listening for connections until the system crashes or | |
1411 | * the daemon is killed with a signal. | |
1412 | */ | |
5260325f | 1413 | for (;;) { |
1414 | if (received_sighup) | |
1415 | sighup_restart(); | |
089fbbd2 | 1416 | if (fdset != NULL) |
1417 | xfree(fdset); | |
52e3daed | 1418 | fdset = (fd_set *)xcalloc(howmany(maxfd + 1, NFDBITS), |
1419 | sizeof(fd_mask)); | |
089fbbd2 | 1420 | |
48e671d5 | 1421 | for (i = 0; i < num_listen_socks; i++) |
1422 | FD_SET(listen_socks[i], fdset); | |
089fbbd2 | 1423 | for (i = 0; i < options.max_startups; i++) |
1424 | if (startup_pipes[i] != -1) | |
1425 | FD_SET(startup_pipes[i], fdset); | |
1426 | ||
1427 | /* Wait in select until there is a connection. */ | |
59c97189 | 1428 | ret = select(maxfd+1, fdset, NULL, NULL, NULL); |
1429 | if (ret < 0 && errno != EINTR) | |
1430 | error("select: %.100s", strerror(errno)); | |
c9130033 | 1431 | if (received_sigterm) { |
bbe88b6d | 1432 | logit("Received signal %d; terminating.", |
010f9726 | 1433 | (int) received_sigterm); |
c9130033 | 1434 | close_listen_socks(); |
1435 | unlink(options.pid_file); | |
1436 | exit(255); | |
1437 | } | |
59c97189 | 1438 | if (key_used && key_do_regen) { |
cb7bd922 | 1439 | generate_ephemeral_server_key(); |
59c97189 | 1440 | key_used = 0; |
1441 | key_do_regen = 0; | |
48e671d5 | 1442 | } |
59c97189 | 1443 | if (ret < 0) |
1444 | continue; | |
1445 | ||
089fbbd2 | 1446 | for (i = 0; i < options.max_startups; i++) |
1447 | if (startup_pipes[i] != -1 && | |
1448 | FD_ISSET(startup_pipes[i], fdset)) { | |
1449 | /* | |
1450 | * the read end of the pipe is ready | |
1451 | * if the child has closed the pipe | |
8abcdba4 | 1452 | * after successful authentication |
089fbbd2 | 1453 | * or if the child has died |
1454 | */ | |
1455 | close(startup_pipes[i]); | |
1456 | startup_pipes[i] = -1; | |
1457 | startups--; | |
1458 | } | |
48e671d5 | 1459 | for (i = 0; i < num_listen_socks; i++) { |
1460 | if (!FD_ISSET(listen_socks[i], fdset)) | |
5260325f | 1461 | continue; |
089fbbd2 | 1462 | fromlen = sizeof(from); |
3efa8ea9 | 1463 | newsock = accept(listen_socks[i], |
1464 | (struct sockaddr *)&from, &fromlen); | |
089fbbd2 | 1465 | if (newsock < 0) { |
1466 | if (errno != EINTR && errno != EWOULDBLOCK) | |
1467 | error("accept: %.100s", strerror(errno)); | |
1468 | continue; | |
1469 | } | |
170694d7 | 1470 | if (unset_nonblock(newsock) == -1) { |
a666e3b1 | 1471 | close(newsock); |
1472 | continue; | |
1473 | } | |
c345cf9d | 1474 | if (drop_connection(startups) == 1) { |
1475 | debug("drop connection #%d", startups); | |
089fbbd2 | 1476 | close(newsock); |
1477 | continue; | |
1478 | } | |
1479 | if (pipe(startup_p) == -1) { | |
1480 | close(newsock); | |
1481 | continue; | |
1482 | } | |
1483 | ||
b9a549d7 | 1484 | if (rexec_flag && socketpair(AF_UNIX, |
1485 | SOCK_STREAM, 0, config_s) == -1) { | |
1486 | error("reexec socketpair: %s", | |
1487 | strerror(errno)); | |
1488 | close(newsock); | |
1489 | close(startup_p[0]); | |
1490 | close(startup_p[1]); | |
1491 | continue; | |
1492 | } | |
1493 | ||
089fbbd2 | 1494 | for (j = 0; j < options.max_startups; j++) |
1495 | if (startup_pipes[j] == -1) { | |
1496 | startup_pipes[j] = startup_p[0]; | |
1497 | if (maxfd < startup_p[0]) | |
1498 | maxfd = startup_p[0]; | |
1499 | startups++; | |
1500 | break; | |
1501 | } | |
2b87da3b | 1502 | |
aa3378df | 1503 | /* |
089fbbd2 | 1504 | * Got connection. Fork a child to handle it, unless |
1505 | * we are in debugging mode. | |
aa3378df | 1506 | */ |
089fbbd2 | 1507 | if (debug_flag) { |
aa3378df | 1508 | /* |
089fbbd2 | 1509 | * In debugging mode. Close the listening |
1510 | * socket, and start processing the | |
1511 | * connection without forking. | |
aa3378df | 1512 | */ |
089fbbd2 | 1513 | debug("Server will not fork when running in debugging mode."); |
48e671d5 | 1514 | close_listen_socks(); |
5260325f | 1515 | sock_in = newsock; |
1516 | sock_out = newsock; | |
b9a549d7 | 1517 | close(startup_p[0]); |
1518 | close(startup_p[1]); | |
5540ea9b | 1519 | startup_pipe = -1; |
3f7a7e4a | 1520 | pid = getpid(); |
b9a549d7 | 1521 | if (rexec_flag) { |
1522 | send_rexec_state(config_s[0], | |
1523 | &cfg); | |
1524 | close(config_s[0]); | |
1525 | } | |
5260325f | 1526 | break; |
089fbbd2 | 1527 | } else { |
1528 | /* | |
1529 | * Normal production daemon. Fork, and have | |
1530 | * the child process the connection. The | |
1531 | * parent continues listening. | |
1532 | */ | |
1533 | if ((pid = fork()) == 0) { | |
1534 | /* | |
3efa8ea9 | 1535 | * Child. Close the listening and |
1536 | * max_startup sockets. Start using | |
1537 | * the accepted socket. Reinitialize | |
1538 | * logging (since our pid has changed). | |
1539 | * We break out of the loop to handle | |
089fbbd2 | 1540 | * the connection. |
1541 | */ | |
1542 | startup_pipe = startup_p[1]; | |
7ace8c3b | 1543 | close_startup_pipes(); |
089fbbd2 | 1544 | close_listen_socks(); |
1545 | sock_in = newsock; | |
1546 | sock_out = newsock; | |
3efa8ea9 | 1547 | log_init(__progname, |
1548 | options.log_level, | |
1549 | options.log_facility, | |
1550 | log_stderr); | |
9216f89c | 1551 | if (rexec_flag) |
1552 | close(config_s[0]); | |
089fbbd2 | 1553 | break; |
1554 | } | |
5260325f | 1555 | } |
5260325f | 1556 | |
089fbbd2 | 1557 | /* Parent. Stay in the loop. */ |
1558 | if (pid < 0) | |
1559 | error("fork: %.100s", strerror(errno)); | |
1560 | else | |
c457707e | 1561 | debug("Forked child %ld.", (long)pid); |
5260325f | 1562 | |
089fbbd2 | 1563 | close(startup_p[1]); |
5260325f | 1564 | |
b9a549d7 | 1565 | if (rexec_flag) { |
1566 | send_rexec_state(config_s[0], &cfg); | |
1567 | close(config_s[0]); | |
1568 | close(config_s[1]); | |
1569 | } | |
1570 | ||
3efa8ea9 | 1571 | /* |
1572 | * Mark that the key has been used (it | |
1573 | * was "given" to the child). | |
1574 | */ | |
59c97189 | 1575 | if ((options.protocol & SSH_PROTO_1) && |
1576 | key_used == 0) { | |
1577 | /* Schedule server key regeneration alarm. */ | |
f00d1f78 | 1578 | signal(SIGALRM, key_regeneration_alarm); |
59c97189 | 1579 | alarm(options.key_regeneration_time); |
1580 | key_used = 1; | |
1581 | } | |
5260325f | 1582 | |
089fbbd2 | 1583 | arc4random_stir(); |
089fbbd2 | 1584 | close(newsock); |
1585 | } | |
48e671d5 | 1586 | /* child process check (or debug mode) */ |
1587 | if (num_listen_socks < 0) | |
1588 | break; | |
5260325f | 1589 | } |
1590 | } | |
8efc0c15 | 1591 | |
5260325f | 1592 | /* This is the child processing a new connection. */ |
cc120685 | 1593 | setproctitle("%s", "[accepted]"); |
5260325f | 1594 | |
8b758bd2 | 1595 | /* |
1596 | * Create a new session and process group since the 4.4BSD | |
1597 | * setlogin() affects the entire process group. We don't | |
1598 | * want the child to be able to affect the parent. | |
1599 | */ | |
1600 | #if !defined(SSHD_ACQUIRES_CTTY) | |
1601 | /* | |
1602 | * If setsid is called, on some platforms sshd will later acquire a | |
1603 | * controlling terminal which will result in "could not set | |
1604 | * controlling tty" errors. | |
1605 | */ | |
1606 | if (!debug_flag && !inetd_flag && setsid() < 0) | |
1607 | error("setsid: %.100s", strerror(errno)); | |
1608 | #endif | |
1609 | ||
b9a549d7 | 1610 | if (rexec_flag) { |
1611 | int fd; | |
1612 | ||
b250e837 | 1613 | debug("rexec start in %d out %d newsock %d pipe %d sock %d", |
1614 | sock_in, sock_out, newsock, startup_pipe, config_s[0]); | |
b9a549d7 | 1615 | dup2(newsock, STDIN_FILENO); |
1616 | dup2(STDIN_FILENO, STDOUT_FILENO); | |
1617 | if (startup_pipe == -1) | |
b250e837 | 1618 | close(REEXEC_STARTUP_PIPE_FD); |
b9a549d7 | 1619 | else |
b250e837 | 1620 | dup2(startup_pipe, REEXEC_STARTUP_PIPE_FD); |
b9a549d7 | 1621 | |
b250e837 | 1622 | dup2(config_s[1], REEXEC_CONFIG_PASS_FD); |
b9a549d7 | 1623 | close(config_s[1]); |
ad148c04 | 1624 | if (startup_pipe != -1) |
1625 | close(startup_pipe); | |
b250e837 | 1626 | |
b9a549d7 | 1627 | execv(rexec_argv[0], rexec_argv); |
1628 | ||
1629 | /* Reexec has failed, fall back and continue */ | |
1630 | error("rexec of %s failed: %s", rexec_argv[0], strerror(errno)); | |
b250e837 | 1631 | recv_rexec_state(REEXEC_CONFIG_PASS_FD, NULL); |
b9a549d7 | 1632 | log_init(__progname, options.log_level, |
1633 | options.log_facility, log_stderr); | |
1634 | ||
1635 | /* Clean up fds */ | |
b250e837 | 1636 | startup_pipe = REEXEC_STARTUP_PIPE_FD; |
b9a549d7 | 1637 | close(config_s[1]); |
b250e837 | 1638 | close(REEXEC_CONFIG_PASS_FD); |
1639 | newsock = sock_out = sock_in = dup(STDIN_FILENO); | |
b9a549d7 | 1640 | if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { |
1641 | dup2(fd, STDIN_FILENO); | |
1642 | dup2(fd, STDOUT_FILENO); | |
1643 | if (fd > STDERR_FILENO) | |
1644 | close(fd); | |
1645 | } | |
b250e837 | 1646 | debug("rexec cleanup in %d out %d newsock %d pipe %d sock %d", |
1647 | sock_in, sock_out, newsock, startup_pipe, config_s[0]); | |
b9a549d7 | 1648 | } |
1649 | ||
aa3378df | 1650 | /* |
1651 | * Disable the key regeneration alarm. We will not regenerate the | |
1652 | * key since we are no longer in a position to give it to anyone. We | |
1653 | * will not restart on SIGHUP since it no longer makes sense. | |
1654 | */ | |
5260325f | 1655 | alarm(0); |
1656 | signal(SIGALRM, SIG_DFL); | |
1657 | signal(SIGHUP, SIG_DFL); | |
1658 | signal(SIGTERM, SIG_DFL); | |
1659 | signal(SIGQUIT, SIG_DFL); | |
1660 | signal(SIGCHLD, SIG_DFL); | |
9aaf9be4 | 1661 | signal(SIGINT, SIG_DFL); |
5260325f | 1662 | |
aa3378df | 1663 | /* |
1664 | * Register our connection. This turns encryption off because we do | |
1665 | * not have a key. | |
1666 | */ | |
5260325f | 1667 | packet_set_connection(sock_in, sock_out); |
07200973 | 1668 | packet_set_server(); |
5260325f | 1669 | |
7c3bc5a2 | 1670 | /* Set SO_KEEPALIVE if requested. */ |
1671 | if (options.tcp_keep_alive && packet_connection_is_on_socket() && | |
1672 | setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) < 0) | |
1673 | error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); | |
1674 | ||
29798ed0 | 1675 | if ((remote_port = get_remote_port()) < 0) { |
1676 | debug("get_remote_port failed"); | |
1677 | cleanup_exit(255); | |
1678 | } | |
3a85986d | 1679 | |
1680 | /* | |
1681 | * We use get_canonical_hostname with usedns = 0 instead of | |
1682 | * get_remote_ipaddr here so IP options will be checked. | |
1683 | */ | |
211f229e | 1684 | (void) get_canonical_hostname(0); |
1685 | /* | |
1686 | * The rest of the code depends on the fact that | |
1687 | * get_remote_ipaddr() caches the remote ip, even if | |
1688 | * the socket goes away. | |
1689 | */ | |
1690 | remote_ip = get_remote_ipaddr(); | |
5260325f | 1691 | |
6039eeef | 1692 | #ifdef SSH_AUDIT_EVENTS |
c00e4d75 | 1693 | audit_connection_from(remote_ip, remote_port); |
1694 | #endif | |
5260325f | 1695 | #ifdef LIBWRAP |
ac28afd8 | 1696 | /* Check whether logins are denied from this host. */ |
33e5359c | 1697 | if (packet_connection_is_on_socket()) { |
5260325f | 1698 | struct request_info req; |
8efc0c15 | 1699 | |
8fbc356d | 1700 | request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0); |
5260325f | 1701 | fromhost(&req); |
8efc0c15 | 1702 | |
5260325f | 1703 | if (!hosts_access(&req)) { |
ac28afd8 | 1704 | debug("Connection refused by tcp wrapper"); |
563834bb | 1705 | refuse(&req); |
ac28afd8 | 1706 | /* NOTREACHED */ |
1707 | fatal("libwrap refuse returns"); | |
5260325f | 1708 | } |
8efc0c15 | 1709 | } |
48e671d5 | 1710 | #endif /* LIBWRAP */ |
ac28afd8 | 1711 | |
5260325f | 1712 | /* Log the connection. */ |
1713 | verbose("Connection from %.500s port %d", remote_ip, remote_port); | |
8efc0c15 | 1714 | |
aa3378df | 1715 | /* |
7b9b0103 | 1716 | * We don't want to listen forever unless the other side |
aa3378df | 1717 | * successfully authenticates itself. So we set up an alarm which is |
1718 | * cleared after successful authentication. A limit of zero | |
7b9b0103 | 1719 | * indicates no limit. Note that we don't set the alarm in debugging |
aa3378df | 1720 | * mode; it is just annoying to have the server exit just when you |
1721 | * are about to discover the bug. | |
1722 | */ | |
f00d1f78 | 1723 | signal(SIGALRM, grace_alarm_handler); |
5260325f | 1724 | if (!debug_flag) |
1725 | alarm(options.login_grace_time); | |
1726 | ||
7368a6c8 | 1727 | sshd_exchange_identification(sock_in, sock_out); |
0598d99d | 1728 | |
5260325f | 1729 | packet_set_nonblocking(); |
1730 | ||
2362db19 | 1731 | /* allocate authentication context */ |
52e3daed | 1732 | authctxt = xcalloc(1, sizeof(*authctxt)); |
2362db19 | 1733 | |
1b394137 | 1734 | authctxt->loginmsg = &loginmsg; |
1735 | ||
2362db19 | 1736 | /* XXX global for cleanup, access from other modules */ |
1737 | the_authctxt = authctxt; | |
1738 | ||
022487ce | 1739 | /* prepare buffer to collect messages to display to user after login */ |
1740 | buffer_init(&loginmsg); | |
1741 | ||
324bf712 | 1742 | if (use_privsep) |
2362db19 | 1743 | if (privsep_preauth(authctxt) == 1) |
324bf712 | 1744 | goto authenticated; |
1853d1ef | 1745 | |
7b2ea3a1 | 1746 | /* perform the key exchange */ |
7b2ea3a1 | 1747 | /* authenticate user and start session */ |
e78a59f5 | 1748 | if (compat20) { |
1749 | do_ssh2_kex(); | |
2362db19 | 1750 | do_authentication2(authctxt); |
e78a59f5 | 1751 | } else { |
1752 | do_ssh1_kex(); | |
2362db19 | 1753 | do_authentication(authctxt); |
e78a59f5 | 1754 | } |
324bf712 | 1755 | /* |
1756 | * If we use privilege separation, the unprivileged child transfers | |
1757 | * the current keystate and exits | |
1758 | */ | |
1759 | if (use_privsep) { | |
b5a28cbc | 1760 | mm_send_keystate(pmonitor); |
1853d1ef | 1761 | exit(0); |
324bf712 | 1762 | } |
1853d1ef | 1763 | |
1764 | authenticated: | |
678143bd | 1765 | /* |
1766 | * Cancel the alarm we set to limit the time taken for | |
1767 | * authentication. | |
1768 | */ | |
1769 | alarm(0); | |
1770 | signal(SIGALRM, SIG_DFL); | |
1771 | if (startup_pipe != -1) { | |
1772 | close(startup_pipe); | |
1773 | startup_pipe = -1; | |
1774 | } | |
1775 | ||
6039eeef | 1776 | #ifdef SSH_AUDIT_EVENTS |
1777 | audit_event(SSH_AUTH_SUCCESS); | |
c00e4d75 | 1778 | #endif |
1779 | ||
762715ce | 1780 | /* |
1853d1ef | 1781 | * In privilege separation, we fork another child and prepare |
1782 | * file descriptor passing. | |
1783 | */ | |
1784 | if (use_privsep) { | |
324bf712 | 1785 | privsep_postauth(authctxt); |
1786 | /* the monitor process [priv] will not return */ | |
1853d1ef | 1787 | if (!compat20) |
1788 | destroy_sensitive_data(); | |
1789 | } | |
1b34c1b3 | 1790 | |
2362db19 | 1791 | /* Start session. */ |
1b34c1b3 | 1792 | do_authenticated(authctxt); |
1793 | ||
63284fbb | 1794 | /* The connection has been terminated. */ |
1795 | verbose("Closing connection to %.100s", remote_ip); | |
8efc0c15 | 1796 | |
d94aa2ae | 1797 | #ifdef USE_PAM |
7fceb20d | 1798 | if (options.use_pam) |
1799 | finish_pam(); | |
d94aa2ae | 1800 | #endif /* USE_PAM */ |
8efc0c15 | 1801 | |
2b0c0925 | 1802 | #ifdef SSH_AUDIT_EVENTS |
1803 | PRIVSEP(audit_event(SSH_CONNECTION_CLOSE)); | |
1804 | #endif | |
1805 | ||
5260325f | 1806 | packet_close(); |
1853d1ef | 1807 | |
1808 | if (use_privsep) | |
1809 | mm_terminate(); | |
1810 | ||
5260325f | 1811 | exit(0); |
1812 | } | |
8efc0c15 | 1813 | |
4f08e98d | 1814 | /* |
1815 | * Decrypt session_key_int using our private server key and private host key | |
1816 | * (key with larger modulus first). | |
1817 | */ | |
1853d1ef | 1818 | int |
4f08e98d | 1819 | ssh1_session_key(BIGNUM *session_key_int) |
1820 | { | |
1821 | int rsafail = 0; | |
1822 | ||
3efa8ea9 | 1823 | if (BN_cmp(sensitive_data.server_key->rsa->n, |
1824 | sensitive_data.ssh1_host_key->rsa->n) > 0) { | |
4f08e98d | 1825 | /* Server key has bigger modulus. */ |
1826 | if (BN_num_bits(sensitive_data.server_key->rsa->n) < | |
3efa8ea9 | 1827 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + |
1828 | SSH_KEY_BITS_RESERVED) { | |
1829 | fatal("do_connection: %s: " | |
1830 | "server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d", | |
4f08e98d | 1831 | get_remote_ipaddr(), |
1832 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
1833 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), | |
1834 | SSH_KEY_BITS_RESERVED); | |
1835 | } | |
1836 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1837 | sensitive_data.server_key->rsa) <= 0) | |
1838 | rsafail++; | |
1839 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1840 | sensitive_data.ssh1_host_key->rsa) <= 0) | |
1841 | rsafail++; | |
1842 | } else { | |
1843 | /* Host key has bigger modulus (or they are equal). */ | |
1844 | if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) < | |
3efa8ea9 | 1845 | BN_num_bits(sensitive_data.server_key->rsa->n) + |
1846 | SSH_KEY_BITS_RESERVED) { | |
1847 | fatal("do_connection: %s: " | |
1848 | "host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d", | |
4f08e98d | 1849 | get_remote_ipaddr(), |
1850 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), | |
1851 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
1852 | SSH_KEY_BITS_RESERVED); | |
1853 | } | |
1854 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1855 | sensitive_data.ssh1_host_key->rsa) < 0) | |
1856 | rsafail++; | |
1857 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1858 | sensitive_data.server_key->rsa) < 0) | |
1859 | rsafail++; | |
1860 | } | |
1861 | return (rsafail); | |
1862 | } | |
5260325f | 1863 | /* |
7b2ea3a1 | 1864 | * SSH1 key exchange |
5260325f | 1865 | */ |
396c147e | 1866 | static void |
1e3b8b07 | 1867 | do_ssh1_kex(void) |
8efc0c15 | 1868 | { |
5260325f | 1869 | int i, len; |
46aa2d1f | 1870 | int rsafail = 0; |
5260325f | 1871 | BIGNUM *session_key_int; |
1e3b8b07 | 1872 | u_char session_key[SSH_SESSION_KEY_LENGTH]; |
1873 | u_char cookie[8]; | |
1874 | u_int cipher_type, auth_mask, protocol_flags; | |
7fdc56c5 | 1875 | u_int32_t rnd = 0; |
5260325f | 1876 | |
aa3378df | 1877 | /* |
1878 | * Generate check bytes that the client must send back in the user | |
1879 | * packet in order for it to be accepted; this is used to defy ip | |
1880 | * spoofing attacks. Note that this only works against somebody | |
1881 | * doing IP spoofing from a remote machine; any machine on the local | |
1882 | * network can still see outgoing packets and catch the random | |
1883 | * cookie. This only affects rhosts authentication, and this is one | |
1884 | * of the reasons why it is inherently insecure. | |
1885 | */ | |
5260325f | 1886 | for (i = 0; i < 8; i++) { |
1887 | if (i % 4 == 0) | |
7fdc56c5 | 1888 | rnd = arc4random(); |
1889 | cookie[i] = rnd & 0xff; | |
1890 | rnd >>= 8; | |
5260325f | 1891 | } |
1892 | ||
aa3378df | 1893 | /* |
1894 | * Send our public key. We include in the packet 64 bits of random | |
1895 | * data that must be matched in the reply in order to prevent IP | |
1896 | * spoofing. | |
1897 | */ | |
5260325f | 1898 | packet_start(SSH_SMSG_PUBLIC_KEY); |
1899 | for (i = 0; i < 8; i++) | |
7b2ea3a1 | 1900 | packet_put_char(cookie[i]); |
5260325f | 1901 | |
1902 | /* Store our public server RSA key. */ | |
fa08c86b | 1903 | packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n)); |
1904 | packet_put_bignum(sensitive_data.server_key->rsa->e); | |
1905 | packet_put_bignum(sensitive_data.server_key->rsa->n); | |
5260325f | 1906 | |
1907 | /* Store our public host RSA key. */ | |
fa08c86b | 1908 | packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); |
1909 | packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e); | |
1910 | packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n); | |
5260325f | 1911 | |
1912 | /* Put protocol flags. */ | |
1913 | packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN); | |
1914 | ||
1915 | /* Declare which ciphers we support. */ | |
94ec8c6b | 1916 | packet_put_int(cipher_mask_ssh1(0)); |
5260325f | 1917 | |
1918 | /* Declare supported authentication types. */ | |
1919 | auth_mask = 0; | |
5260325f | 1920 | if (options.rhosts_rsa_authentication) |
1921 | auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA; | |
1922 | if (options.rsa_authentication) | |
1923 | auth_mask |= 1 << SSH_AUTH_RSA; | |
5ba55ada | 1924 | if (options.challenge_response_authentication == 1) |
5260325f | 1925 | auth_mask |= 1 << SSH_AUTH_TIS; |
5260325f | 1926 | if (options.password_authentication) |
1927 | auth_mask |= 1 << SSH_AUTH_PASSWORD; | |
1928 | packet_put_int(auth_mask); | |
1929 | ||
1930 | /* Send the packet and wait for it to be sent. */ | |
1931 | packet_send(); | |
1932 | packet_write_wait(); | |
1933 | ||
fa08c86b | 1934 | debug("Sent %d bit server key and %d bit host key.", |
1935 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
1936 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); | |
5260325f | 1937 | |
1938 | /* Read clients reply (cipher type and session key). */ | |
54a5250f | 1939 | packet_read_expect(SSH_CMSG_SESSION_KEY); |
5260325f | 1940 | |
2d86a6cc | 1941 | /* Get cipher type and check whether we accept this. */ |
5260325f | 1942 | cipher_type = packet_get_char(); |
1943 | ||
94ec8c6b | 1944 | if (!(cipher_mask_ssh1(0) & (1 << cipher_type))) |
2d86a6cc | 1945 | packet_disconnect("Warning: client selects unsupported cipher."); |
1946 | ||
5260325f | 1947 | /* Get check bytes from the packet. These must match those we |
1948 | sent earlier with the public key packet. */ | |
1949 | for (i = 0; i < 8; i++) | |
7b2ea3a1 | 1950 | if (cookie[i] != packet_get_char()) |
5260325f | 1951 | packet_disconnect("IP Spoofing check bytes do not match."); |
1952 | ||
1953 | debug("Encryption type: %.200s", cipher_name(cipher_type)); | |
1954 | ||
1955 | /* Get the encrypted integer. */ | |
b775c6f2 | 1956 | if ((session_key_int = BN_new()) == NULL) |
1957 | fatal("do_ssh1_kex: BN_new failed"); | |
20b279e6 | 1958 | packet_get_bignum(session_key_int); |
5260325f | 1959 | |
5260325f | 1960 | protocol_flags = packet_get_int(); |
1961 | packet_set_protocol_flags(protocol_flags); | |
95500969 | 1962 | packet_check_eom(); |
5260325f | 1963 | |
4f08e98d | 1964 | /* Decrypt session_key_int using host/server keys */ |
1853d1ef | 1965 | rsafail = PRIVSEP(ssh1_session_key(session_key_int)); |
1966 | ||
aa3378df | 1967 | /* |
1968 | * Extract session key from the decrypted integer. The key is in the | |
1969 | * least significant 256 bits of the integer; the first byte of the | |
1970 | * key is in the highest bits. | |
1971 | */ | |
46aa2d1f | 1972 | if (!rsafail) { |
1973 | BN_mask_bits(session_key_int, sizeof(session_key) * 8); | |
1974 | len = BN_num_bytes(session_key_int); | |
2ceb8101 | 1975 | if (len < 0 || (u_int)len > sizeof(session_key)) { |
46aa2d1f | 1976 | error("do_connection: bad session key len from %s: " |
5ca51e19 | 1977 | "session_key_int %d > sizeof(session_key) %lu", |
1978 | get_remote_ipaddr(), len, (u_long)sizeof(session_key)); | |
46aa2d1f | 1979 | rsafail++; |
1980 | } else { | |
1981 | memset(session_key, 0, sizeof(session_key)); | |
1982 | BN_bn2bin(session_key_int, | |
1983 | session_key + sizeof(session_key) - len); | |
00be5382 | 1984 | |
8bbf1fa6 | 1985 | derive_ssh1_session_id( |
f2107e97 | 1986 | sensitive_data.ssh1_host_key->rsa->n, |
8bbf1fa6 | 1987 | sensitive_data.server_key->rsa->n, |
1988 | cookie, session_id); | |
00be5382 | 1989 | /* |
1990 | * Xor the first 16 bytes of the session key with the | |
1991 | * session id. | |
1992 | */ | |
1993 | for (i = 0; i < 16; i++) | |
1994 | session_key[i] ^= session_id[i]; | |
46aa2d1f | 1995 | } |
1996 | } | |
1997 | if (rsafail) { | |
00be5382 | 1998 | int bytes = BN_num_bytes(session_key_int); |
f6b1ba8f | 1999 | u_char *buf = xmalloc(bytes); |
00be5382 | 2000 | MD5_CTX md; |
2001 | ||
bbe88b6d | 2002 | logit("do_connection: generating a fake encryption key"); |
00be5382 | 2003 | BN_bn2bin(session_key_int, buf); |
2004 | MD5_Init(&md); | |
2005 | MD5_Update(&md, buf, bytes); | |
2006 | MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); | |
2007 | MD5_Final(session_key, &md); | |
2008 | MD5_Init(&md); | |
2009 | MD5_Update(&md, session_key, 16); | |
2010 | MD5_Update(&md, buf, bytes); | |
2011 | MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); | |
2012 | MD5_Final(session_key + 16, &md); | |
2013 | memset(buf, 0, bytes); | |
2014 | xfree(buf); | |
0572fe75 | 2015 | for (i = 0; i < 16; i++) |
2016 | session_id[i] = session_key[i] ^ session_key[i + 16]; | |
46aa2d1f | 2017 | } |
1853d1ef | 2018 | /* Destroy the private and public keys. No longer. */ |
63284fbb | 2019 | destroy_sensitive_data(); |
00be5382 | 2020 | |
1853d1ef | 2021 | if (use_privsep) |
2022 | mm_ssh1_session_id(session_id); | |
2023 | ||
7b2ea3a1 | 2024 | /* Destroy the decrypted integer. It is no longer needed. */ |
2025 | BN_clear_free(session_key_int); | |
2026 | ||
5260325f | 2027 | /* Set the session key. From this on all communications will be encrypted. */ |
2028 | packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type); | |
2029 | ||
2030 | /* Destroy our copy of the session key. It is no longer needed. */ | |
2031 | memset(session_key, 0, sizeof(session_key)); | |
2032 | ||
2033 | debug("Received session key; encryption turned on."); | |
2034 | ||
c242fc96 | 2035 | /* Send an acknowledgment packet. Note that this packet is sent encrypted. */ |
5260325f | 2036 | packet_start(SSH_SMSG_SUCCESS); |
2037 | packet_send(); | |
2038 | packet_write_wait(); | |
5260325f | 2039 | } |
e78a59f5 | 2040 | |
2041 | /* | |
2042 | * SSH2 key exchange: diffie-hellman-group1-sha1 | |
2043 | */ | |
396c147e | 2044 | static void |
1e3b8b07 | 2045 | do_ssh2_kex(void) |
e78a59f5 | 2046 | { |
e78a59f5 | 2047 | Kex *kex; |
e78a59f5 | 2048 | |
a8be9f80 | 2049 | if (options.ciphers != NULL) { |
6ae2364d | 2050 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = |
a8be9f80 | 2051 | myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; |
2052 | } | |
1ad64a93 | 2053 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = |
2054 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]); | |
2055 | myproposal[PROPOSAL_ENC_ALGS_STOC] = | |
2056 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); | |
2057 | ||
b2552997 | 2058 | if (options.macs != NULL) { |
2059 | myproposal[PROPOSAL_MAC_ALGS_CTOS] = | |
2060 | myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; | |
2061 | } | |
07200973 | 2062 | if (options.compression == COMP_NONE) { |
636f76ca | 2063 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = |
2064 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "none"; | |
07200973 | 2065 | } else if (options.compression == COMP_DELAYED) { |
2066 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = | |
2067 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com"; | |
636f76ca | 2068 | } |
3efa8ea9 | 2069 | |
fa08c86b | 2070 | myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = list_hostkey_types(); |
2071 | ||
7a37c112 | 2072 | /* start key exchange */ |
d8ee838b | 2073 | kex = kex_setup(myproposal); |
98a58eda | 2074 | kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server; |
41e5bd9a | 2075 | kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server; |
98a58eda | 2076 | kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; |
2ff8003a | 2077 | kex->kex[KEX_DH_GEX_SHA256] = kexgex_server; |
a5c9ffdb | 2078 | kex->server = 1; |
2079 | kex->client_version_string=client_version_string; | |
2080 | kex->server_version_string=server_version_string; | |
2081 | kex->load_host_key=&get_hostkey_by_type; | |
1853d1ef | 2082 | kex->host_key_index=&get_hostkey_index; |
94ec8c6b | 2083 | |
7a37c112 | 2084 | xxx_kex = kex; |
2085 | ||
c422989b | 2086 | dispatch_run(DISPATCH_BLOCK, &kex->done, kex); |
94ec8c6b | 2087 | |
d1ac6175 | 2088 | session_id2 = kex->session_id; |
2089 | session_id2_len = kex->session_id_len; | |
2090 | ||
94ec8c6b | 2091 | #ifdef DEBUG_KEXDH |
2092 | /* send 1st encrypted/maced/compressed message */ | |
2093 | packet_start(SSH2_MSG_IGNORE); | |
2094 | packet_put_cstring("markus"); | |
2095 | packet_send(); | |
2096 | packet_write_wait(); | |
2097 | #endif | |
a5c9ffdb | 2098 | debug("KEX done"); |
e78a59f5 | 2099 | } |
2362db19 | 2100 | |
2101 | /* server specific fatal cleanup */ | |
2102 | void | |
2103 | cleanup_exit(int i) | |
2104 | { | |
2105 | if (the_authctxt) | |
2106 | do_cleanup(the_authctxt); | |
6039eeef | 2107 | #ifdef SSH_AUDIT_EVENTS |
c00e4d75 | 2108 | /* done after do_cleanup so it can cancel the PAM auth 'thread' */ |
2109 | if (!use_privsep || mm_is_monitor()) | |
6039eeef | 2110 | audit_event(SSH_CONNECTION_ABANDON); |
c00e4d75 | 2111 | #endif |
2362db19 | 2112 | _exit(i); |
2113 | } |