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00146caa | 1 | /* $OpenBSD: sshd.c,v 1.339 2006/07/22 20:48:23 stevesk Exp $ */ |
8efc0c15 | 2 | /* |
5260325f | 3 | * Author: Tatu Ylonen <ylo@cs.hut.fi> |
4 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland | |
5 | * All rights reserved | |
bcbf86ec | 6 | * This program is the ssh daemon. It listens for connections from clients, |
7 | * and performs authentication, executes use commands or shell, and forwards | |
5260325f | 8 | * information to/from the application to the user client over an encrypted |
bcbf86ec | 9 | * connection. This can also handle forwarding of X11, TCP/IP, and |
10 | * authentication agent connections. | |
e78a59f5 | 11 | * |
bcbf86ec | 12 | * As far as I am concerned, the code I have written for this software |
13 | * can be used freely for any purpose. Any derived versions of this | |
14 | * software must be clearly marked as such, and if the derived work is | |
15 | * incompatible with the protocol description in the RFC file, it must be | |
16 | * called by a name other than "ssh" or "Secure Shell". | |
17 | * | |
18 | * SSH2 implementation: | |
1853d1ef | 19 | * Privilege Separation: |
bcbf86ec | 20 | * |
1853d1ef | 21 | * Copyright (c) 2000, 2001, 2002 Markus Friedl. All rights reserved. |
22 | * Copyright (c) 2002 Niels Provos. All rights reserved. | |
bcbf86ec | 23 | * |
24 | * Redistribution and use in source and binary forms, with or without | |
25 | * modification, are permitted provided that the following conditions | |
26 | * are met: | |
27 | * 1. Redistributions of source code must retain the above copyright | |
28 | * notice, this list of conditions and the following disclaimer. | |
29 | * 2. Redistributions in binary form must reproduce the above copyright | |
30 | * notice, this list of conditions and the following disclaimer in the | |
31 | * documentation and/or other materials provided with the distribution. | |
32 | * | |
33 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR | |
34 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES | |
35 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. | |
36 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, | |
37 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
38 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
39 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
40 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
41 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF | |
42 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
5260325f | 43 | */ |
8efc0c15 | 44 | |
45 | #include "includes.h" | |
bd7c69ea | 46 | |
aa2eae64 | 47 | #include <sys/types.h> |
4095f623 | 48 | #ifdef HAVE_SYS_STAT_H |
49 | # include <sys/stat.h> | |
50 | #endif | |
51 | #include <sys/ioctl.h> | |
5b04a8bf | 52 | #include <sys/socket.h> |
aa2eae64 | 53 | #include <sys/wait.h> |
a75f5360 | 54 | |
028094f4 | 55 | #include <errno.h> |
d3221cca | 56 | #include <fcntl.h> |
28cb0a43 | 57 | #include <netdb.h> |
b5b88c19 | 58 | #ifdef HAVE_PATHS_H |
a75f5360 | 59 | #include <paths.h> |
b5b88c19 | 60 | #endif |
22bbb3e6 | 61 | #include <grp.h> |
b1842393 | 62 | #include <pwd.h> |
ada68823 | 63 | #include <signal.h> |
00146caa | 64 | #include <string.h> |
8efc0c15 | 65 | |
42f11eb2 | 66 | #include <openssl/dh.h> |
67 | #include <openssl/bn.h> | |
436c347c | 68 | #include <openssl/md5.h> |
1853d1ef | 69 | #include <openssl/rand.h> |
6e879cb4 | 70 | #ifdef HAVE_SECUREWARE |
71 | #include <sys/security.h> | |
72 | #include <prot.h> | |
73 | #endif | |
42f11eb2 | 74 | |
75 | #include "ssh.h" | |
76 | #include "ssh1.h" | |
77 | #include "ssh2.h" | |
8efc0c15 | 78 | #include "xmalloc.h" |
79 | #include "rsa.h" | |
1729c161 | 80 | #include "sshpty.h" |
8efc0c15 | 81 | #include "packet.h" |
42f11eb2 | 82 | #include "log.h" |
8efc0c15 | 83 | #include "servconf.h" |
84 | #include "uidswap.h" | |
85 | #include "compat.h" | |
7368a6c8 | 86 | #include "buffer.h" |
b9a549d7 | 87 | #include "bufaux.h" |
42f11eb2 | 88 | #include "cipher.h" |
e78a59f5 | 89 | #include "kex.h" |
7368a6c8 | 90 | #include "key.h" |
94ec8c6b | 91 | #include "dh.h" |
e78a59f5 | 92 | #include "myproposal.h" |
a306f2dd | 93 | #include "authfile.h" |
42f11eb2 | 94 | #include "pathnames.h" |
95 | #include "atomicio.h" | |
96 | #include "canohost.h" | |
97 | #include "auth.h" | |
98 | #include "misc.h" | |
b9a549d7 | 99 | #include "msg.h" |
a5c9ffdb | 100 | #include "dispatch.h" |
e4d7f734 | 101 | #include "channels.h" |
1b34c1b3 | 102 | #include "session.h" |
1853d1ef | 103 | #include "monitor_mm.h" |
104 | #include "monitor.h" | |
105 | #include "monitor_wrap.h" | |
106 | #include "monitor_fdpass.h" | |
28015df4 | 107 | #include "version.h" |
8efc0c15 | 108 | |
109 | #ifdef LIBWRAP | |
110 | #include <tcpd.h> | |
111 | #include <syslog.h> | |
112 | int allow_severity = LOG_INFO; | |
113 | int deny_severity = LOG_WARNING; | |
114 | #endif /* LIBWRAP */ | |
115 | ||
116 | #ifndef O_NOCTTY | |
117 | #define O_NOCTTY 0 | |
118 | #endif | |
119 | ||
b250e837 | 120 | /* Re-exec fds */ |
121 | #define REEXEC_DEVCRYPTO_RESERVED_FD (STDERR_FILENO + 1) | |
122 | #define REEXEC_STARTUP_PIPE_FD (STDERR_FILENO + 2) | |
123 | #define REEXEC_CONFIG_PASS_FD (STDERR_FILENO + 3) | |
124 | #define REEXEC_MIN_FREE_FD (STDERR_FILENO + 4) | |
125 | ||
260d427b | 126 | extern char *__progname; |
260d427b | 127 | |
8efc0c15 | 128 | /* Server configuration options. */ |
129 | ServerOptions options; | |
130 | ||
131 | /* Name of the server configuration file. */ | |
42f11eb2 | 132 | char *config_file_name = _PATH_SERVER_CONFIG_FILE; |
8efc0c15 | 133 | |
5260325f | 134 | /* |
135 | * Debug mode flag. This can be set on the command line. If debug | |
136 | * mode is enabled, extra debugging output will be sent to the system | |
137 | * log, the daemon will not go to background, and will exit after processing | |
138 | * the first connection. | |
139 | */ | |
8efc0c15 | 140 | int debug_flag = 0; |
141 | ||
f87f09aa | 142 | /* Flag indicating that the daemon should only test the configuration and keys. */ |
143 | int test_flag = 0; | |
144 | ||
8efc0c15 | 145 | /* Flag indicating that the daemon is being started from inetd. */ |
146 | int inetd_flag = 0; | |
147 | ||
0b6fbf03 | 148 | /* Flag indicating that sshd should not detach and become a daemon. */ |
149 | int no_daemon_flag = 0; | |
150 | ||
6a17f9c2 | 151 | /* debug goes to stderr unless inetd_flag is set */ |
152 | int log_stderr = 0; | |
153 | ||
8efc0c15 | 154 | /* Saved arguments to main(). */ |
155 | char **saved_argv; | |
4d33e531 | 156 | int saved_argc; |
8efc0c15 | 157 | |
b9a549d7 | 158 | /* re-exec */ |
159 | int rexeced_flag = 0; | |
160 | int rexec_flag = 1; | |
161 | int rexec_argc = 0; | |
162 | char **rexec_argv; | |
163 | ||
aa3378df | 164 | /* |
48e671d5 | 165 | * The sockets that the server is listening; this is used in the SIGHUP |
166 | * signal handler. | |
aa3378df | 167 | */ |
48e671d5 | 168 | #define MAX_LISTEN_SOCKS 16 |
169 | int listen_socks[MAX_LISTEN_SOCKS]; | |
170 | int num_listen_socks = 0; | |
8efc0c15 | 171 | |
aa3378df | 172 | /* |
173 | * the client's version string, passed by sshd2 in compat mode. if != NULL, | |
174 | * sshd will skip the version-number exchange | |
175 | */ | |
5260325f | 176 | char *client_version_string = NULL; |
7368a6c8 | 177 | char *server_version_string = NULL; |
8efc0c15 | 178 | |
7a37c112 | 179 | /* for rekeying XXX fixme */ |
180 | Kex *xxx_kex; | |
181 | ||
aa3378df | 182 | /* |
183 | * Any really sensitive data in the application is contained in this | |
184 | * structure. The idea is that this structure could be locked into memory so | |
185 | * that the pages do not get written into swap. However, there are some | |
186 | * problems. The private key contains BIGNUMs, and we do not (in principle) | |
187 | * have access to the internals of them, and locking just the structure is | |
188 | * not very useful. Currently, memory locking is not implemented. | |
189 | */ | |
5260325f | 190 | struct { |
cb7bd922 | 191 | Key *server_key; /* ephemeral server key */ |
fa08c86b | 192 | Key *ssh1_host_key; /* ssh1 host key */ |
193 | Key **host_keys; /* all private host keys */ | |
194 | int have_ssh1_key; | |
195 | int have_ssh2_key; | |
00be5382 | 196 | u_char ssh1_cookie[SSH_SESSION_KEY_LENGTH]; |
8efc0c15 | 197 | } sensitive_data; |
198 | ||
aa3378df | 199 | /* |
59c97189 | 200 | * Flag indicating whether the RSA server key needs to be regenerated. |
201 | * Is set in the SIGALRM handler and cleared when the key is regenerated. | |
aa3378df | 202 | */ |
7a934d1b | 203 | static volatile sig_atomic_t key_do_regen = 0; |
8efc0c15 | 204 | |
c9130033 | 205 | /* This is set to true when a signal is received. */ |
7a934d1b | 206 | static volatile sig_atomic_t received_sighup = 0; |
207 | static volatile sig_atomic_t received_sigterm = 0; | |
8efc0c15 | 208 | |
7368a6c8 | 209 | /* session identifier, used by RSA-auth */ |
1e3b8b07 | 210 | u_char session_id[16]; |
e7c0f9d5 | 211 | |
a306f2dd | 212 | /* same for ssh2 */ |
1e3b8b07 | 213 | u_char *session_id2 = NULL; |
a27002e5 | 214 | u_int session_id2_len = 0; |
a306f2dd | 215 | |
c345cf9d | 216 | /* record remote hostname or ip */ |
1e3b8b07 | 217 | u_int utmp_len = MAXHOSTNAMELEN; |
c345cf9d | 218 | |
7ace8c3b | 219 | /* options.max_startup sized array of fd ints */ |
220 | int *startup_pipes = NULL; | |
221 | int startup_pipe; /* in child */ | |
222 | ||
1853d1ef | 223 | /* variables used for privilege separation */ |
d231781a | 224 | int use_privsep = -1; |
a9b33b95 | 225 | struct monitor *pmonitor = NULL; |
1853d1ef | 226 | |
2362db19 | 227 | /* global authentication context */ |
228 | Authctxt *the_authctxt = NULL; | |
229 | ||
d231781a | 230 | /* sshd_config buffer */ |
231 | Buffer cfg; | |
232 | ||
be2ca0c9 | 233 | /* message to be displayed after login */ |
234 | Buffer loginmsg; | |
235 | ||
7368a6c8 | 236 | /* Prototypes for various functions defined later in this file. */ |
396c147e | 237 | void destroy_sensitive_data(void); |
1853d1ef | 238 | void demote_sensitive_data(void); |
c8d54615 | 239 | |
396c147e | 240 | static void do_ssh1_kex(void); |
241 | static void do_ssh2_kex(void); | |
94ec8c6b | 242 | |
48e671d5 | 243 | /* |
244 | * Close all listening sockets | |
245 | */ | |
396c147e | 246 | static void |
48e671d5 | 247 | close_listen_socks(void) |
248 | { | |
249 | int i; | |
e424e241 | 250 | |
48e671d5 | 251 | for (i = 0; i < num_listen_socks; i++) |
252 | close(listen_socks[i]); | |
253 | num_listen_socks = -1; | |
254 | } | |
255 | ||
7ace8c3b | 256 | static void |
257 | close_startup_pipes(void) | |
258 | { | |
259 | int i; | |
e424e241 | 260 | |
7ace8c3b | 261 | if (startup_pipes) |
262 | for (i = 0; i < options.max_startups; i++) | |
263 | if (startup_pipes[i] != -1) | |
264 | close(startup_pipes[i]); | |
265 | } | |
266 | ||
5260325f | 267 | /* |
268 | * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP; | |
269 | * the effect is to reread the configuration file (and to regenerate | |
270 | * the server key). | |
271 | */ | |
3efa8ea9 | 272 | |
273 | /*ARGSUSED*/ | |
396c147e | 274 | static void |
5260325f | 275 | sighup_handler(int sig) |
8efc0c15 | 276 | { |
6056eb35 | 277 | int save_errno = errno; |
278 | ||
5260325f | 279 | received_sighup = 1; |
280 | signal(SIGHUP, sighup_handler); | |
6056eb35 | 281 | errno = save_errno; |
8efc0c15 | 282 | } |
283 | ||
5260325f | 284 | /* |
285 | * Called from the main program after receiving SIGHUP. | |
286 | * Restarts the server. | |
287 | */ | |
396c147e | 288 | static void |
5ca51e19 | 289 | sighup_restart(void) |
8efc0c15 | 290 | { |
bbe88b6d | 291 | logit("Received SIGHUP; restarting."); |
48e671d5 | 292 | close_listen_socks(); |
7ace8c3b | 293 | close_startup_pipes(); |
5260325f | 294 | execv(saved_argv[0], saved_argv); |
bbe88b6d | 295 | logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0], |
e424e241 | 296 | strerror(errno)); |
5260325f | 297 | exit(1); |
8efc0c15 | 298 | } |
299 | ||
5260325f | 300 | /* |
301 | * Generic signal handler for terminating signals in the master daemon. | |
5260325f | 302 | */ |
3efa8ea9 | 303 | /*ARGSUSED*/ |
396c147e | 304 | static void |
5260325f | 305 | sigterm_handler(int sig) |
8efc0c15 | 306 | { |
c9130033 | 307 | received_sigterm = sig; |
8efc0c15 | 308 | } |
309 | ||
5260325f | 310 | /* |
311 | * SIGCHLD handler. This is called whenever a child dies. This will then | |
c9130033 | 312 | * reap any zombies left by exited children. |
5260325f | 313 | */ |
3efa8ea9 | 314 | /*ARGSUSED*/ |
396c147e | 315 | static void |
5260325f | 316 | main_sigchld_handler(int sig) |
8efc0c15 | 317 | { |
5260325f | 318 | int save_errno = errno; |
e424e241 | 319 | pid_t pid; |
5260325f | 320 | int status; |
5ad13cd7 | 321 | |
8c38e88b | 322 | while ((pid = waitpid(-1, &status, WNOHANG)) > 0 || |
323 | (pid < 0 && errno == EINTR)) | |
5260325f | 324 | ; |
5ad13cd7 | 325 | |
5260325f | 326 | signal(SIGCHLD, main_sigchld_handler); |
327 | errno = save_errno; | |
8efc0c15 | 328 | } |
329 | ||
5260325f | 330 | /* |
331 | * Signal handler for the alarm after the login grace period has expired. | |
332 | */ | |
3efa8ea9 | 333 | /*ARGSUSED*/ |
396c147e | 334 | static void |
5260325f | 335 | grace_alarm_handler(int sig) |
8efc0c15 | 336 | { |
c9130033 | 337 | /* XXX no idea how fix this signal handler */ |
338 | ||
a9b33b95 | 339 | if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0) |
340 | kill(pmonitor->m_pid, SIGALRM); | |
341 | ||
5260325f | 342 | /* Log error and exit. */ |
26b9a3d2 | 343 | fatal("Timeout before authentication for %s", get_remote_ipaddr()); |
5260325f | 344 | } |
8efc0c15 | 345 | |
5260325f | 346 | /* |
347 | * Signal handler for the key regeneration alarm. Note that this | |
348 | * alarm only occurs in the daemon waiting for connections, and it does not | |
349 | * do anything with the private key or random state before forking. | |
350 | * Thus there should be no concurrency control/asynchronous execution | |
351 | * problems. | |
352 | */ | |
396c147e | 353 | static void |
cb7bd922 | 354 | generate_ephemeral_server_key(void) |
fa08c86b | 355 | { |
7fdc56c5 | 356 | u_int32_t rnd = 0; |
00be5382 | 357 | int i; |
358 | ||
cd332296 | 359 | verbose("Generating %s%d bit RSA key.", |
76ca7b01 | 360 | sensitive_data.server_key ? "new " : "", options.server_key_bits); |
fa08c86b | 361 | if (sensitive_data.server_key != NULL) |
362 | key_free(sensitive_data.server_key); | |
cd332296 | 363 | sensitive_data.server_key = key_generate(KEY_RSA1, |
76ca7b01 | 364 | options.server_key_bits); |
365 | verbose("RSA key generation complete."); | |
00be5382 | 366 | |
367 | for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) { | |
368 | if (i % 4 == 0) | |
7fdc56c5 | 369 | rnd = arc4random(); |
370 | sensitive_data.ssh1_cookie[i] = rnd & 0xff; | |
371 | rnd >>= 8; | |
00be5382 | 372 | } |
373 | arc4random_stir(); | |
fa08c86b | 374 | } |
f546c780 | 375 | |
3efa8ea9 | 376 | /*ARGSUSED*/ |
396c147e | 377 | static void |
5260325f | 378 | key_regeneration_alarm(int sig) |
379 | { | |
380 | int save_errno = errno; | |
e424e241 | 381 | |
59c97189 | 382 | signal(SIGALRM, SIG_DFL); |
5260325f | 383 | errno = save_errno; |
59c97189 | 384 | key_do_regen = 1; |
5260325f | 385 | } |
8efc0c15 | 386 | |
396c147e | 387 | static void |
7368a6c8 | 388 | sshd_exchange_identification(int sock_in, int sock_out) |
389 | { | |
2ceb8101 | 390 | u_int i; |
391 | int mismatch; | |
7368a6c8 | 392 | int remote_major, remote_minor; |
a8be9f80 | 393 | int major, minor; |
7368a6c8 | 394 | char *s; |
395 | char buf[256]; /* Must not be larger than remote_version. */ | |
396 | char remote_version[256]; /* Must be at least as big as buf. */ | |
397 | ||
a8be9f80 | 398 | if ((options.protocol & SSH_PROTO_1) && |
399 | (options.protocol & SSH_PROTO_2)) { | |
400 | major = PROTOCOL_MAJOR_1; | |
401 | minor = 99; | |
402 | } else if (options.protocol & SSH_PROTO_2) { | |
403 | major = PROTOCOL_MAJOR_2; | |
404 | minor = PROTOCOL_MINOR_2; | |
405 | } else { | |
406 | major = PROTOCOL_MAJOR_1; | |
407 | minor = PROTOCOL_MINOR_1; | |
408 | } | |
409 | snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", major, minor, SSH_VERSION); | |
7368a6c8 | 410 | server_version_string = xstrdup(buf); |
411 | ||
7b390973 | 412 | /* Send our protocol version identification. */ |
413 | if (atomicio(vwrite, sock_out, server_version_string, | |
414 | strlen(server_version_string)) | |
415 | != strlen(server_version_string)) { | |
416 | logit("Could not write ident string to %s", get_remote_ipaddr()); | |
2362db19 | 417 | cleanup_exit(255); |
7b390973 | 418 | } |
419 | ||
420 | /* Read other sides version identification. */ | |
421 | memset(buf, 0, sizeof(buf)); | |
422 | for (i = 0; i < sizeof(buf) - 1; i++) { | |
423 | if (atomicio(read, sock_in, &buf[i], 1) != 1) { | |
424 | logit("Did not receive identification string from %s", | |
425 | get_remote_ipaddr()); | |
2362db19 | 426 | cleanup_exit(255); |
7368a6c8 | 427 | } |
7b390973 | 428 | if (buf[i] == '\r') { |
429 | buf[i] = 0; | |
430 | /* Kludge for F-Secure Macintosh < 1.0.2 */ | |
431 | if (i == 12 && | |
432 | strncmp(buf, "SSH-1.5-W1.0", 12) == 0) | |
7368a6c8 | 433 | break; |
7b390973 | 434 | continue; |
435 | } | |
436 | if (buf[i] == '\n') { | |
437 | buf[i] = 0; | |
438 | break; | |
7368a6c8 | 439 | } |
7368a6c8 | 440 | } |
7b390973 | 441 | buf[sizeof(buf) - 1] = 0; |
442 | client_version_string = xstrdup(buf); | |
7368a6c8 | 443 | |
444 | /* | |
445 | * Check that the versions match. In future this might accept | |
446 | * several versions and set appropriate flags to handle them. | |
447 | */ | |
448 | if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n", | |
449 | &remote_major, &remote_minor, remote_version) != 3) { | |
6ae2364d | 450 | s = "Protocol mismatch.\n"; |
dc54438a | 451 | (void) atomicio(vwrite, sock_out, s, strlen(s)); |
7368a6c8 | 452 | close(sock_in); |
453 | close(sock_out); | |
bbe88b6d | 454 | logit("Bad protocol version identification '%.100s' from %s", |
7368a6c8 | 455 | client_version_string, get_remote_ipaddr()); |
2362db19 | 456 | cleanup_exit(255); |
7368a6c8 | 457 | } |
458 | debug("Client protocol version %d.%d; client software version %.100s", | |
184eed6a | 459 | remote_major, remote_minor, remote_version); |
7368a6c8 | 460 | |
e78a59f5 | 461 | compat_datafellows(remote_version); |
462 | ||
9a87e2ac | 463 | if (datafellows & SSH_BUG_PROBE) { |
bbe88b6d | 464 | logit("probed from %s with %s. Don't panic.", |
9a87e2ac | 465 | get_remote_ipaddr(), client_version_string); |
2362db19 | 466 | cleanup_exit(255); |
9a87e2ac | 467 | } |
468 | ||
3a1c54d4 | 469 | if (datafellows & SSH_BUG_SCANNER) { |
bbe88b6d | 470 | logit("scanned from %s with %s. Don't panic.", |
3a1c54d4 | 471 | get_remote_ipaddr(), client_version_string); |
2362db19 | 472 | cleanup_exit(255); |
3a1c54d4 | 473 | } |
474 | ||
a8be9f80 | 475 | mismatch = 0; |
6aacefa7 | 476 | switch (remote_major) { |
7368a6c8 | 477 | case 1: |
a306f2dd | 478 | if (remote_minor == 99) { |
479 | if (options.protocol & SSH_PROTO_2) | |
480 | enable_compat20(); | |
481 | else | |
482 | mismatch = 1; | |
483 | break; | |
484 | } | |
a8be9f80 | 485 | if (!(options.protocol & SSH_PROTO_1)) { |
486 | mismatch = 1; | |
487 | break; | |
488 | } | |
7368a6c8 | 489 | if (remote_minor < 3) { |
089fbbd2 | 490 | packet_disconnect("Your ssh version is too old and " |
7368a6c8 | 491 | "is no longer supported. Please install a newer version."); |
492 | } else if (remote_minor == 3) { | |
493 | /* note that this disables agent-forwarding */ | |
494 | enable_compat13(); | |
495 | } | |
a8be9f80 | 496 | break; |
e78a59f5 | 497 | case 2: |
a8be9f80 | 498 | if (options.protocol & SSH_PROTO_2) { |
e78a59f5 | 499 | enable_compat20(); |
500 | break; | |
501 | } | |
502 | /* FALLTHROUGH */ | |
6ae2364d | 503 | default: |
a8be9f80 | 504 | mismatch = 1; |
505 | break; | |
506 | } | |
507 | chop(server_version_string); | |
a8be9f80 | 508 | debug("Local version string %.200s", server_version_string); |
509 | ||
510 | if (mismatch) { | |
7368a6c8 | 511 | s = "Protocol major versions differ.\n"; |
dc54438a | 512 | (void) atomicio(vwrite, sock_out, s, strlen(s)); |
7368a6c8 | 513 | close(sock_in); |
514 | close(sock_out); | |
bbe88b6d | 515 | logit("Protocol major versions differ for %s: %.200s vs. %.200s", |
a8be9f80 | 516 | get_remote_ipaddr(), |
517 | server_version_string, client_version_string); | |
2362db19 | 518 | cleanup_exit(255); |
7368a6c8 | 519 | } |
a306f2dd | 520 | } |
521 | ||
fa08c86b | 522 | /* Destroy the host and server keys. They will no longer be needed. */ |
a306f2dd | 523 | void |
524 | destroy_sensitive_data(void) | |
525 | { | |
fa08c86b | 526 | int i; |
527 | ||
528 | if (sensitive_data.server_key) { | |
529 | key_free(sensitive_data.server_key); | |
530 | sensitive_data.server_key = NULL; | |
531 | } | |
184eed6a | 532 | for (i = 0; i < options.num_host_key_files; i++) { |
fa08c86b | 533 | if (sensitive_data.host_keys[i]) { |
534 | key_free(sensitive_data.host_keys[i]); | |
535 | sensitive_data.host_keys[i] = NULL; | |
536 | } | |
537 | } | |
538 | sensitive_data.ssh1_host_key = NULL; | |
00be5382 | 539 | memset(sensitive_data.ssh1_cookie, 0, SSH_SESSION_KEY_LENGTH); |
fa08c86b | 540 | } |
fa08c86b | 541 | |
1853d1ef | 542 | /* Demote private to public keys for network child */ |
543 | void | |
544 | demote_sensitive_data(void) | |
545 | { | |
546 | Key *tmp; | |
547 | int i; | |
548 | ||
549 | if (sensitive_data.server_key) { | |
550 | tmp = key_demote(sensitive_data.server_key); | |
551 | key_free(sensitive_data.server_key); | |
552 | sensitive_data.server_key = tmp; | |
553 | } | |
554 | ||
555 | for (i = 0; i < options.num_host_key_files; i++) { | |
556 | if (sensitive_data.host_keys[i]) { | |
557 | tmp = key_demote(sensitive_data.host_keys[i]); | |
558 | key_free(sensitive_data.host_keys[i]); | |
559 | sensitive_data.host_keys[i] = tmp; | |
560 | if (tmp->type == KEY_RSA1) | |
561 | sensitive_data.ssh1_host_key = tmp; | |
562 | } | |
563 | } | |
564 | ||
565 | /* We do not clear ssh1_host key and cookie. XXX - Okay Niels? */ | |
566 | } | |
567 | ||
51aeb639 | 568 | static void |
1853d1ef | 569 | privsep_preauth_child(void) |
570 | { | |
7fdc56c5 | 571 | u_int32_t rnd[256]; |
6ded293b | 572 | gid_t gidset[1]; |
2ea6de2b | 573 | struct passwd *pw; |
e424e241 | 574 | int i; |
1853d1ef | 575 | |
576 | /* Enable challenge-response authentication for privilege separation */ | |
577 | privsep_challenge_enable(); | |
578 | ||
579 | for (i = 0; i < 256; i++) | |
7fdc56c5 | 580 | rnd[i] = arc4random(); |
581 | RAND_seed(rnd, sizeof(rnd)); | |
1853d1ef | 582 | |
583 | /* Demote the private keys to public keys. */ | |
584 | demote_sensitive_data(); | |
585 | ||
2ea6de2b | 586 | if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) |
cdc4fc39 | 587 | fatal("Privilege separation user %s does not exist", |
588 | SSH_PRIVSEP_USER); | |
2ea6de2b | 589 | memset(pw->pw_passwd, 0, strlen(pw->pw_passwd)); |
590 | endpwent(); | |
591 | ||
343288b8 | 592 | /* Change our root directory */ |
1c352e97 | 593 | if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1) |
594 | fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR, | |
595 | strerror(errno)); | |
1853d1ef | 596 | if (chdir("/") == -1) |
edfb66cb | 597 | fatal("chdir(\"/\"): %s", strerror(errno)); |
762715ce | 598 | |
1853d1ef | 599 | /* Drop our privileges */ |
2ea6de2b | 600 | debug3("privsep user:group %u:%u", (u_int)pw->pw_uid, |
601 | (u_int)pw->pw_gid); | |
87809a1f | 602 | #if 0 |
6ff58a4b | 603 | /* XXX not ready, too heavy after chroot */ |
2ea6de2b | 604 | do_setusercontext(pw); |
87809a1f | 605 | #else |
606 | gidset[0] = pw->pw_gid; | |
87809a1f | 607 | if (setgroups(1, gidset) < 0) |
608 | fatal("setgroups: %.100s", strerror(errno)); | |
609 | permanently_set_uid(pw); | |
610 | #endif | |
1853d1ef | 611 | } |
612 | ||
2362db19 | 613 | static int |
614 | privsep_preauth(Authctxt *authctxt) | |
1853d1ef | 615 | { |
1853d1ef | 616 | int status; |
324bf712 | 617 | pid_t pid; |
1853d1ef | 618 | |
324bf712 | 619 | /* Set up unprivileged child process to deal with network data */ |
b5a28cbc | 620 | pmonitor = monitor_init(); |
324bf712 | 621 | /* Store a pointer to the kex for later rekeying */ |
b5a28cbc | 622 | pmonitor->m_pkex = &xxx_kex; |
324bf712 | 623 | |
624 | pid = fork(); | |
625 | if (pid == -1) { | |
626 | fatal("fork of unprivileged child failed"); | |
627 | } else if (pid != 0) { | |
c457707e | 628 | debug2("Network child is on pid %ld", (long)pid); |
324bf712 | 629 | |
b5a28cbc | 630 | close(pmonitor->m_recvfd); |
a9b33b95 | 631 | pmonitor->m_pid = pid; |
2362db19 | 632 | monitor_child_preauth(authctxt, pmonitor); |
b5a28cbc | 633 | close(pmonitor->m_sendfd); |
324bf712 | 634 | |
635 | /* Sync memory */ | |
b5a28cbc | 636 | monitor_sync(pmonitor); |
324bf712 | 637 | |
638 | /* Wait for the child's exit status */ | |
8c38e88b | 639 | while (waitpid(pid, &status, 0) < 0) |
640 | if (errno != EINTR) | |
641 | break; | |
2362db19 | 642 | return (1); |
324bf712 | 643 | } else { |
644 | /* child */ | |
645 | ||
b5a28cbc | 646 | close(pmonitor->m_sendfd); |
324bf712 | 647 | |
648 | /* Demote the child */ | |
649 | if (getuid() == 0 || geteuid() == 0) | |
650 | privsep_preauth_child(); | |
47c36e5b | 651 | setproctitle("%s", "[net]"); |
324bf712 | 652 | } |
2362db19 | 653 | return (0); |
324bf712 | 654 | } |
655 | ||
656 | static void | |
657 | privsep_postauth(Authctxt *authctxt) | |
658 | { | |
94d8258b | 659 | #ifdef DISABLE_FD_PASSING |
d170feb1 | 660 | if (1) { |
661 | #else | |
1853d1ef | 662 | if (authctxt->pw->pw_uid == 0 || options.use_login) { |
d170feb1 | 663 | #endif |
1853d1ef | 664 | /* File descriptor passing is broken or root login */ |
1853d1ef | 665 | use_privsep = 0; |
ae25711b | 666 | goto skip; |
1853d1ef | 667 | } |
762715ce | 668 | |
1853d1ef | 669 | /* New socket pair */ |
b5a28cbc | 670 | monitor_reinit(pmonitor); |
1853d1ef | 671 | |
b5a28cbc | 672 | pmonitor->m_pid = fork(); |
673 | if (pmonitor->m_pid == -1) | |
1853d1ef | 674 | fatal("fork of unprivileged child failed"); |
b5a28cbc | 675 | else if (pmonitor->m_pid != 0) { |
c457707e | 676 | debug2("User child is on pid %ld", (long)pmonitor->m_pid); |
b5a28cbc | 677 | close(pmonitor->m_recvfd); |
f143ed33 | 678 | buffer_clear(&loginmsg); |
b5a28cbc | 679 | monitor_child_postauth(pmonitor); |
1853d1ef | 680 | |
681 | /* NEVERREACHED */ | |
682 | exit(0); | |
683 | } | |
684 | ||
b5a28cbc | 685 | close(pmonitor->m_sendfd); |
1853d1ef | 686 | |
687 | /* Demote the private keys to public keys. */ | |
688 | demote_sensitive_data(); | |
689 | ||
690 | /* Drop privileges */ | |
691 | do_setusercontext(authctxt->pw); | |
692 | ||
ae25711b | 693 | skip: |
1853d1ef | 694 | /* It is safe now to apply the key state */ |
b5a28cbc | 695 | monitor_apply_keystate(pmonitor); |
07200973 | 696 | |
697 | /* | |
698 | * Tell the packet layer that authentication was successful, since | |
699 | * this information is not part of the key state. | |
700 | */ | |
701 | packet_set_authenticated(); | |
1853d1ef | 702 | } |
703 | ||
396c147e | 704 | static char * |
fa08c86b | 705 | list_hostkey_types(void) |
706 | { | |
3469eac4 | 707 | Buffer b; |
b6c7b7b7 | 708 | const char *p; |
709 | char *ret; | |
fa08c86b | 710 | int i; |
3469eac4 | 711 | |
712 | buffer_init(&b); | |
184eed6a | 713 | for (i = 0; i < options.num_host_key_files; i++) { |
fa08c86b | 714 | Key *key = sensitive_data.host_keys[i]; |
715 | if (key == NULL) | |
716 | continue; | |
6aacefa7 | 717 | switch (key->type) { |
fa08c86b | 718 | case KEY_RSA: |
719 | case KEY_DSA: | |
3469eac4 | 720 | if (buffer_len(&b) > 0) |
721 | buffer_append(&b, ",", 1); | |
722 | p = key_ssh_name(key); | |
723 | buffer_append(&b, p, strlen(p)); | |
fa08c86b | 724 | break; |
725 | } | |
726 | } | |
3469eac4 | 727 | buffer_append(&b, "\0", 1); |
b6c7b7b7 | 728 | ret = xstrdup(buffer_ptr(&b)); |
3469eac4 | 729 | buffer_free(&b); |
b6c7b7b7 | 730 | debug("list_hostkey_types: %s", ret); |
731 | return ret; | |
fa08c86b | 732 | } |
733 | ||
1853d1ef | 734 | Key * |
fa08c86b | 735 | get_hostkey_by_type(int type) |
736 | { | |
737 | int i; | |
e424e241 | 738 | |
184eed6a | 739 | for (i = 0; i < options.num_host_key_files; i++) { |
fa08c86b | 740 | Key *key = sensitive_data.host_keys[i]; |
741 | if (key != NULL && key->type == type) | |
742 | return key; | |
743 | } | |
744 | return NULL; | |
7368a6c8 | 745 | } |
746 | ||
1853d1ef | 747 | Key * |
748 | get_hostkey_by_index(int ind) | |
749 | { | |
750 | if (ind < 0 || ind >= options.num_host_key_files) | |
751 | return (NULL); | |
752 | return (sensitive_data.host_keys[ind]); | |
753 | } | |
754 | ||
755 | int | |
756 | get_hostkey_index(Key *key) | |
757 | { | |
758 | int i; | |
e424e241 | 759 | |
1853d1ef | 760 | for (i = 0; i < options.num_host_key_files; i++) { |
761 | if (key == sensitive_data.host_keys[i]) | |
762 | return (i); | |
763 | } | |
764 | return (-1); | |
765 | } | |
766 | ||
c345cf9d | 767 | /* |
768 | * returns 1 if connection should be dropped, 0 otherwise. | |
769 | * dropping starts at connection #max_startups_begin with a probability | |
770 | * of (max_startups_rate/100). the probability increases linearly until | |
771 | * all connections are dropped for startups > max_startups | |
772 | */ | |
396c147e | 773 | static int |
c345cf9d | 774 | drop_connection(int startups) |
775 | { | |
1c5eab6f | 776 | int p, r; |
c345cf9d | 777 | |
778 | if (startups < options.max_startups_begin) | |
779 | return 0; | |
780 | if (startups >= options.max_startups) | |
781 | return 1; | |
782 | if (options.max_startups_rate == 100) | |
783 | return 1; | |
784 | ||
785 | p = 100 - options.max_startups_rate; | |
786 | p *= startups - options.max_startups_begin; | |
1c5eab6f | 787 | p /= options.max_startups - options.max_startups_begin; |
c345cf9d | 788 | p += options.max_startups_rate; |
1c5eab6f | 789 | r = arc4random() % 100; |
c345cf9d | 790 | |
e9aec1d4 | 791 | debug("drop_connection: p %d, r %d", p, r); |
c345cf9d | 792 | return (r < p) ? 1 : 0; |
793 | } | |
794 | ||
2717fa0f | 795 | static void |
796 | usage(void) | |
797 | { | |
85ac7a84 | 798 | fprintf(stderr, "%s, %s\n", |
4526e8c2 | 799 | SSH_RELEASE, SSLeay_version(SSLEAY_VERSION)); |
65edde94 | 800 | fprintf(stderr, |
801 | "usage: sshd [-46Ddeiqt] [-b bits] [-f config_file] [-g login_grace_time]\n" | |
802 | " [-h host_key_file] [-k key_gen_time] [-o option] [-p port] [-u len]\n" | |
803 | ); | |
2717fa0f | 804 | exit(1); |
805 | } | |
806 | ||
b9a549d7 | 807 | static void |
808 | send_rexec_state(int fd, Buffer *conf) | |
809 | { | |
810 | Buffer m; | |
811 | ||
812 | debug3("%s: entering fd = %d config len %d", __func__, fd, | |
813 | buffer_len(conf)); | |
814 | ||
815 | /* | |
816 | * Protocol from reexec master to child: | |
817 | * string configuration | |
818 | * u_int ephemeral_key_follows | |
819 | * bignum e (only if ephemeral_key_follows == 1) | |
820 | * bignum n " | |
821 | * bignum d " | |
822 | * bignum iqmp " | |
823 | * bignum p " | |
824 | * bignum q " | |
72f02ae7 | 825 | * string rngseed (only if OpenSSL is not self-seeded) |
b9a549d7 | 826 | */ |
827 | buffer_init(&m); | |
828 | buffer_put_cstring(&m, buffer_ptr(conf)); | |
829 | ||
f2107e97 | 830 | if (sensitive_data.server_key != NULL && |
b9a549d7 | 831 | sensitive_data.server_key->type == KEY_RSA1) { |
832 | buffer_put_int(&m, 1); | |
833 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->e); | |
834 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->n); | |
835 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->d); | |
836 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->iqmp); | |
837 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->p); | |
838 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->q); | |
839 | } else | |
840 | buffer_put_int(&m, 0); | |
841 | ||
72f02ae7 | 842 | #ifndef OPENSSL_PRNG_ONLY |
843 | rexec_send_rng_seed(&m); | |
844 | #endif | |
845 | ||
b9a549d7 | 846 | if (ssh_msg_send(fd, 0, &m) == -1) |
847 | fatal("%s: ssh_msg_send failed", __func__); | |
848 | ||
849 | buffer_free(&m); | |
850 | ||
851 | debug3("%s: done", __func__); | |
852 | } | |
853 | ||
854 | static void | |
855 | recv_rexec_state(int fd, Buffer *conf) | |
856 | { | |
857 | Buffer m; | |
858 | char *cp; | |
859 | u_int len; | |
860 | ||
861 | debug3("%s: entering fd = %d", __func__, fd); | |
862 | ||
863 | buffer_init(&m); | |
864 | ||
865 | if (ssh_msg_recv(fd, &m) == -1) | |
866 | fatal("%s: ssh_msg_recv failed", __func__); | |
867 | if (buffer_get_char(&m) != 0) | |
868 | fatal("%s: rexec version mismatch", __func__); | |
869 | ||
870 | cp = buffer_get_string(&m, &len); | |
871 | if (conf != NULL) | |
872 | buffer_append(conf, cp, len + 1); | |
873 | xfree(cp); | |
874 | ||
875 | if (buffer_get_int(&m)) { | |
876 | if (sensitive_data.server_key != NULL) | |
877 | key_free(sensitive_data.server_key); | |
878 | sensitive_data.server_key = key_new_private(KEY_RSA1); | |
879 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->e); | |
880 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->n); | |
881 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->d); | |
882 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->iqmp); | |
883 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->p); | |
884 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->q); | |
885 | rsa_generate_additional_parameters( | |
886 | sensitive_data.server_key->rsa); | |
887 | } | |
72f02ae7 | 888 | |
889 | #ifndef OPENSSL_PRNG_ONLY | |
890 | rexec_recv_rng_seed(&m); | |
891 | #endif | |
892 | ||
b9a549d7 | 893 | buffer_free(&m); |
894 | ||
895 | debug3("%s: done", __func__); | |
896 | } | |
897 | ||
5260325f | 898 | /* |
899 | * Main program for the daemon. | |
900 | */ | |
8efc0c15 | 901 | int |
902 | main(int ac, char **av) | |
903 | { | |
5260325f | 904 | extern char *optarg; |
905 | extern int optind; | |
52e3daed | 906 | int opt, j, i, on = 1; |
83529a6b | 907 | int sock_in = -1, sock_out = -1, newsock = -1; |
9da5c3c9 | 908 | pid_t pid; |
48e671d5 | 909 | socklen_t fromlen; |
48e671d5 | 910 | fd_set *fdset; |
911 | struct sockaddr_storage from; | |
5260325f | 912 | const char *remote_ip; |
913 | int remote_port; | |
5260325f | 914 | FILE *f; |
48e671d5 | 915 | struct addrinfo *ai; |
916 | char ntop[NI_MAXHOST], strport[NI_MAXSERV]; | |
c5894280 | 917 | char *line; |
48e671d5 | 918 | int listen_sock, maxfd; |
9216f89c | 919 | int startup_p[2] = { -1 , -1 }, config_s[2] = { -1 , -1 }; |
089fbbd2 | 920 | int startups = 0; |
aeaa3d9e | 921 | Key *key; |
2362db19 | 922 | Authctxt *authctxt; |
59c97189 | 923 | int ret, key_used = 0; |
5260325f | 924 | |
6e879cb4 | 925 | #ifdef HAVE_SECUREWARE |
926 | (void)set_auth_parameters(ac, av); | |
927 | #endif | |
fda04d7d | 928 | __progname = ssh_get_progname(av[0]); |
264dce47 | 929 | init_rng(); |
930 | ||
d0104542 | 931 | /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */ |
4d33e531 | 932 | saved_argc = ac; |
7706b4c7 | 933 | rexec_argc = ac; |
01d35895 | 934 | saved_argv = xcalloc(ac + 1, sizeof(*saved_argv)); |
d0104542 | 935 | for (i = 0; i < ac; i++) |
936 | saved_argv[i] = xstrdup(av[i]); | |
f420d2ba | 937 | saved_argv[i] = NULL; |
d0104542 | 938 | |
939 | #ifndef HAVE_SETPROCTITLE | |
940 | /* Prepare for later setproctitle emulation */ | |
941 | compat_init_setproctitle(ac, av); | |
416c732d | 942 | av = saved_argv; |
d0104542 | 943 | #endif |
5260325f | 944 | |
a4c0faa2 | 945 | if (geteuid() == 0 && setgroups(0, NULL) == -1) |
946 | debug("setgroups(): %.200s", strerror(errno)); | |
947 | ||
fd6168c1 | 948 | /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ |
949 | sanitise_stdfd(); | |
950 | ||
5260325f | 951 | /* Initialize configuration options to their default values. */ |
952 | initialize_server_options(&options); | |
953 | ||
954 | /* Parse command-line arguments. */ | |
b9a549d7 | 955 | while ((opt = getopt(ac, av, "f:p:b:k:h:g:u:o:dDeiqrtQR46")) != -1) { |
5260325f | 956 | switch (opt) { |
48e671d5 | 957 | case '4': |
31b41ceb | 958 | options.address_family = AF_INET; |
48e671d5 | 959 | break; |
960 | case '6': | |
31b41ceb | 961 | options.address_family = AF_INET6; |
48e671d5 | 962 | break; |
5260325f | 963 | case 'f': |
964 | config_file_name = optarg; | |
965 | break; | |
966 | case 'd': | |
e053cd2c | 967 | if (debug_flag == 0) { |
bcbf86ec | 968 | debug_flag = 1; |
969 | options.log_level = SYSLOG_LEVEL_DEBUG1; | |
e053cd2c | 970 | } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) |
bcbf86ec | 971 | options.log_level++; |
5260325f | 972 | break; |
0b6fbf03 | 973 | case 'D': |
974 | no_daemon_flag = 1; | |
975 | break; | |
ff14faf1 | 976 | case 'e': |
977 | log_stderr = 1; | |
978 | break; | |
5260325f | 979 | case 'i': |
980 | inetd_flag = 1; | |
981 | break; | |
b9a549d7 | 982 | case 'r': |
983 | rexec_flag = 0; | |
984 | break; | |
985 | case 'R': | |
986 | rexeced_flag = 1; | |
987 | inetd_flag = 1; | |
988 | break; | |
5260325f | 989 | case 'Q': |
9bd5b720 | 990 | /* ignored */ |
5260325f | 991 | break; |
992 | case 'q': | |
993 | options.log_level = SYSLOG_LEVEL_QUIET; | |
994 | break; | |
995 | case 'b': | |
3efa8ea9 | 996 | options.server_key_bits = (int)strtonum(optarg, 256, |
997 | 32768, NULL); | |
5260325f | 998 | break; |
999 | case 'p': | |
48e671d5 | 1000 | options.ports_from_cmdline = 1; |
bcbf86ec | 1001 | if (options.num_ports >= MAX_PORTS) { |
1002 | fprintf(stderr, "too many ports.\n"); | |
1003 | exit(1); | |
1004 | } | |
2d2a2c65 | 1005 | options.ports[options.num_ports++] = a2port(optarg); |
1006 | if (options.ports[options.num_ports-1] == 0) { | |
1007 | fprintf(stderr, "Bad port number.\n"); | |
1008 | exit(1); | |
1009 | } | |
5260325f | 1010 | break; |
1011 | case 'g': | |
e2b1fb42 | 1012 | if ((options.login_grace_time = convtime(optarg)) == -1) { |
1013 | fprintf(stderr, "Invalid login grace time.\n"); | |
1014 | exit(1); | |
1015 | } | |
5260325f | 1016 | break; |
1017 | case 'k': | |
e2b1fb42 | 1018 | if ((options.key_regeneration_time = convtime(optarg)) == -1) { |
1019 | fprintf(stderr, "Invalid key regeneration interval.\n"); | |
1020 | exit(1); | |
1021 | } | |
5260325f | 1022 | break; |
1023 | case 'h': | |
fa08c86b | 1024 | if (options.num_host_key_files >= MAX_HOSTKEYS) { |
1025 | fprintf(stderr, "too many host keys.\n"); | |
1026 | exit(1); | |
1027 | } | |
1028 | options.host_key_files[options.num_host_key_files++] = optarg; | |
5260325f | 1029 | break; |
f87f09aa | 1030 | case 't': |
1031 | test_flag = 1; | |
1032 | break; | |
c345cf9d | 1033 | case 'u': |
3efa8ea9 | 1034 | utmp_len = (u_int)strtonum(optarg, 0, MAXHOSTNAMELEN+1, NULL); |
67f04db1 | 1035 | if (utmp_len > MAXHOSTNAMELEN) { |
1036 | fprintf(stderr, "Invalid utmp length.\n"); | |
1037 | exit(1); | |
1038 | } | |
c345cf9d | 1039 | break; |
2717fa0f | 1040 | case 'o': |
c5894280 | 1041 | line = xstrdup(optarg); |
1042 | if (process_server_config_line(&options, line, | |
d231781a | 1043 | "command-line", 0, NULL, NULL, NULL, NULL) != 0) |
184eed6a | 1044 | exit(1); |
c5894280 | 1045 | xfree(line); |
2717fa0f | 1046 | break; |
5260325f | 1047 | case '?': |
1048 | default: | |
2717fa0f | 1049 | usage(); |
1050 | break; | |
5260325f | 1051 | } |
1052 | } | |
b9a549d7 | 1053 | if (rexeced_flag || inetd_flag) |
1054 | rexec_flag = 0; | |
1055 | if (rexec_flag && (av[0] == NULL || *av[0] != '/')) | |
1056 | fatal("sshd re-exec requires execution with an absolute path"); | |
1057 | if (rexeced_flag) | |
b250e837 | 1058 | closefrom(REEXEC_MIN_FREE_FD); |
1059 | else | |
1060 | closefrom(REEXEC_DEVCRYPTO_RESERVED_FD); | |
b9a549d7 | 1061 | |
1a92bd7e | 1062 | SSLeay_add_all_algorithms(); |
5260325f | 1063 | |
48e671d5 | 1064 | /* |
1065 | * Force logging to stderr until we have loaded the private host | |
1066 | * key (unless started from inetd) | |
1067 | */ | |
1fe6a48f | 1068 | log_init(__progname, |
980c9344 | 1069 | options.log_level == SYSLOG_LEVEL_NOT_SET ? |
1070 | SYSLOG_LEVEL_INFO : options.log_level, | |
1071 | options.log_facility == SYSLOG_FACILITY_NOT_SET ? | |
1072 | SYSLOG_FACILITY_AUTH : options.log_facility, | |
51efad8c | 1073 | log_stderr || !inetd_flag); |
48e671d5 | 1074 | |
351f44a0 | 1075 | /* |
1076 | * Unset KRB5CCNAME, otherwise the user's session may inherit it from | |
1077 | * root's environment | |
d1cf9a87 | 1078 | */ |
3bfd27d5 | 1079 | if (getenv("KRB5CCNAME") != NULL) |
1080 | unsetenv("KRB5CCNAME"); | |
1081 | ||
ef51930f | 1082 | #ifdef _UNICOS |
e5ba4718 | 1083 | /* Cray can define user privs drop all privs now! |
1a23ac2c | 1084 | * Not needed on PRIV_SU systems! |
1085 | */ | |
1086 | drop_cray_privs(); | |
1087 | #endif | |
1088 | ||
b9a549d7 | 1089 | sensitive_data.server_key = NULL; |
1090 | sensitive_data.ssh1_host_key = NULL; | |
1091 | sensitive_data.have_ssh1_key = 0; | |
1092 | sensitive_data.have_ssh2_key = 0; | |
1093 | ||
1094 | /* Fetch our configuration */ | |
1095 | buffer_init(&cfg); | |
1096 | if (rexeced_flag) | |
b250e837 | 1097 | recv_rexec_state(REEXEC_CONFIG_PASS_FD, &cfg); |
b9a549d7 | 1098 | else |
1099 | load_server_config(config_file_name, &cfg); | |
1100 | ||
d231781a | 1101 | parse_server_config(&options, rexeced_flag ? "rexec" : config_file_name, |
1102 | &cfg, NULL, NULL, NULL); | |
5260325f | 1103 | |
72f02ae7 | 1104 | seed_rng(); |
1105 | ||
5260325f | 1106 | /* Fill in default values for those options not explicitly set. */ |
1107 | fill_default_server_options(&options); | |
1108 | ||
31b41ceb | 1109 | /* set default channel AF */ |
1110 | channel_set_af(options.address_family); | |
1111 | ||
5260325f | 1112 | /* Check that there are no remaining arguments. */ |
1113 | if (optind < ac) { | |
1114 | fprintf(stderr, "Extra argument %s.\n", av[optind]); | |
1115 | exit(1); | |
8efc0c15 | 1116 | } |
5260325f | 1117 | |
4526e8c2 | 1118 | debug("sshd version %.100s", SSH_RELEASE); |
5260325f | 1119 | |
fa08c86b | 1120 | /* load private host keys */ |
52e3daed | 1121 | sensitive_data.host_keys = xcalloc(options.num_host_key_files, |
343288b8 | 1122 | sizeof(Key *)); |
184eed6a | 1123 | for (i = 0; i < options.num_host_key_files; i++) |
1e3b8b07 | 1124 | sensitive_data.host_keys[i] = NULL; |
a306f2dd | 1125 | |
184eed6a | 1126 | for (i = 0; i < options.num_host_key_files; i++) { |
aeaa3d9e | 1127 | key = key_load_private(options.host_key_files[i], "", NULL); |
1128 | sensitive_data.host_keys[i] = key; | |
fa08c86b | 1129 | if (key == NULL) { |
58cfa257 | 1130 | error("Could not load host key: %s", |
1131 | options.host_key_files[i]); | |
aeaa3d9e | 1132 | sensitive_data.host_keys[i] = NULL; |
fa08c86b | 1133 | continue; |
a306f2dd | 1134 | } |
6aacefa7 | 1135 | switch (key->type) { |
fa08c86b | 1136 | case KEY_RSA1: |
1137 | sensitive_data.ssh1_host_key = key; | |
1138 | sensitive_data.have_ssh1_key = 1; | |
1139 | break; | |
1140 | case KEY_RSA: | |
1141 | case KEY_DSA: | |
1142 | sensitive_data.have_ssh2_key = 1; | |
1143 | break; | |
a306f2dd | 1144 | } |
aeaa3d9e | 1145 | debug("private host key: #%d type %d %s", i, key->type, |
1146 | key_type(key)); | |
fa08c86b | 1147 | } |
1148 | if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) { | |
bbe88b6d | 1149 | logit("Disabling protocol version 1. Could not load host key"); |
fa08c86b | 1150 | options.protocol &= ~SSH_PROTO_1; |
1151 | } | |
1152 | if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) { | |
bbe88b6d | 1153 | logit("Disabling protocol version 2. Could not load host key"); |
fa08c86b | 1154 | options.protocol &= ~SSH_PROTO_2; |
a306f2dd | 1155 | } |
6a416424 | 1156 | if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) { |
bbe88b6d | 1157 | logit("sshd: no hostkeys available -- exiting."); |
5260325f | 1158 | exit(1); |
1159 | } | |
5260325f | 1160 | |
a306f2dd | 1161 | /* Check certain values for sanity. */ |
1162 | if (options.protocol & SSH_PROTO_1) { | |
1163 | if (options.server_key_bits < 512 || | |
1164 | options.server_key_bits > 32768) { | |
1165 | fprintf(stderr, "Bad server key size.\n"); | |
1166 | exit(1); | |
1167 | } | |
1168 | /* | |
1169 | * Check that server and host key lengths differ sufficiently. This | |
1170 | * is necessary to make double encryption work with rsaref. Oh, I | |
1171 | * hate software patents. I dont know if this can go? Niels | |
1172 | */ | |
1173 | if (options.server_key_bits > | |
e424e241 | 1174 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) - |
1175 | SSH_KEY_BITS_RESERVED && options.server_key_bits < | |
1176 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + | |
1177 | SSH_KEY_BITS_RESERVED) { | |
a306f2dd | 1178 | options.server_key_bits = |
e424e241 | 1179 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + |
1180 | SSH_KEY_BITS_RESERVED; | |
a306f2dd | 1181 | debug("Forcing server key to %d bits to make it differ from host key.", |
1182 | options.server_key_bits); | |
1183 | } | |
1184 | } | |
1185 | ||
3cc54fbb | 1186 | if (use_privsep) { |
3cc54fbb | 1187 | struct stat st; |
1188 | ||
3efa8ea9 | 1189 | if (getpwnam(SSH_PRIVSEP_USER) == NULL) |
3cc54fbb | 1190 | fatal("Privilege separation user %s does not exist", |
1191 | SSH_PRIVSEP_USER); | |
1192 | if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) || | |
1193 | (S_ISDIR(st.st_mode) == 0)) | |
1194 | fatal("Missing privilege separation directory: %s", | |
1195 | _PATH_PRIVSEP_CHROOT_DIR); | |
b9b82dab | 1196 | |
1197 | #ifdef HAVE_CYGWIN | |
1198 | if (check_ntsec(_PATH_PRIVSEP_CHROOT_DIR) && | |
1199 | (st.st_uid != getuid () || | |
1200 | (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)) | |
1201 | #else | |
a56313d7 | 1202 | if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0) |
b9b82dab | 1203 | #endif |
5f021474 | 1204 | fatal("%s must be owned by root and not group or " |
1205 | "world-writable.", _PATH_PRIVSEP_CHROOT_DIR); | |
3cc54fbb | 1206 | } |
1207 | ||
f87f09aa | 1208 | /* Configuration looks good, so exit if in test mode. */ |
1209 | if (test_flag) | |
1210 | exit(0); | |
1211 | ||
018a5ea3 | 1212 | /* |
1213 | * Clear out any supplemental groups we may have inherited. This | |
1214 | * prevents inadvertent creation of files with bad modes (in the | |
aff51935 | 1215 | * portable version at least, it's certainly possible for PAM |
1216 | * to create a file, and we can't control the code in every | |
018a5ea3 | 1217 | * module which might be used). |
1218 | */ | |
1219 | if (setgroups(0, NULL) < 0) | |
1220 | debug("setgroups() failed: %.200s", strerror(errno)); | |
1221 | ||
b9a549d7 | 1222 | if (rexec_flag) { |
52e3daed | 1223 | rexec_argv = xcalloc(rexec_argc + 2, sizeof(char *)); |
b9a549d7 | 1224 | for (i = 0; i < rexec_argc; i++) { |
1225 | debug("rexec_argv[%d]='%s'", i, saved_argv[i]); | |
1226 | rexec_argv[i] = saved_argv[i]; | |
1227 | } | |
1228 | rexec_argv[rexec_argc] = "-R"; | |
1229 | rexec_argv[rexec_argc + 1] = NULL; | |
1230 | } | |
1231 | ||
a306f2dd | 1232 | /* Initialize the log (it is reinitialized below in case we forked). */ |
25c31d49 | 1233 | if (debug_flag && (!inetd_flag || rexeced_flag)) |
5260325f | 1234 | log_stderr = 1; |
1fe6a48f | 1235 | log_init(__progname, options.log_level, options.log_facility, log_stderr); |
5260325f | 1236 | |
a306f2dd | 1237 | /* |
1238 | * If not in debugging mode, and not started from inetd, disconnect | |
1239 | * from the controlling terminal, and fork. The original process | |
1240 | * exits. | |
1241 | */ | |
0b6fbf03 | 1242 | if (!(debug_flag || inetd_flag || no_daemon_flag)) { |
8efc0c15 | 1243 | #ifdef TIOCNOTTY |
5260325f | 1244 | int fd; |
8efc0c15 | 1245 | #endif /* TIOCNOTTY */ |
5260325f | 1246 | if (daemon(0, 0) < 0) |
1247 | fatal("daemon() failed: %.200s", strerror(errno)); | |
1248 | ||
1249 | /* Disconnect from the controlling tty. */ | |
8efc0c15 | 1250 | #ifdef TIOCNOTTY |
5ca51e19 | 1251 | fd = open(_PATH_TTY, O_RDWR | O_NOCTTY); |
5260325f | 1252 | if (fd >= 0) { |
1253 | (void) ioctl(fd, TIOCNOTTY, NULL); | |
1254 | close(fd); | |
1255 | } | |
8efc0c15 | 1256 | #endif /* TIOCNOTTY */ |
8efc0c15 | 1257 | } |
5260325f | 1258 | /* Reinitialize the log (because of the fork above). */ |
1fe6a48f | 1259 | log_init(__progname, options.log_level, options.log_facility, log_stderr); |
5260325f | 1260 | |
5260325f | 1261 | /* Initialize the random number generator. */ |
1262 | arc4random_stir(); | |
1263 | ||
1264 | /* Chdir to the root directory so that the current disk can be | |
1265 | unmounted if desired. */ | |
1266 | chdir("/"); | |
184eed6a | 1267 | |
1d3c30db | 1268 | /* ignore SIGPIPE */ |
1269 | signal(SIGPIPE, SIG_IGN); | |
5260325f | 1270 | |
5260325f | 1271 | /* Start listening for a socket, unless started from inetd. */ |
1272 | if (inetd_flag) { | |
b9a549d7 | 1273 | int fd; |
1274 | ||
4c8722d9 | 1275 | startup_pipe = -1; |
b9a549d7 | 1276 | if (rexeced_flag) { |
b250e837 | 1277 | close(REEXEC_CONFIG_PASS_FD); |
b9a549d7 | 1278 | sock_in = sock_out = dup(STDIN_FILENO); |
1279 | if (!debug_flag) { | |
b250e837 | 1280 | startup_pipe = dup(REEXEC_STARTUP_PIPE_FD); |
1281 | close(REEXEC_STARTUP_PIPE_FD); | |
b9a549d7 | 1282 | } |
1283 | } else { | |
1284 | sock_in = dup(STDIN_FILENO); | |
1285 | sock_out = dup(STDOUT_FILENO); | |
1286 | } | |
a306f2dd | 1287 | /* |
1288 | * We intentionally do not close the descriptors 0, 1, and 2 | |
b9a549d7 | 1289 | * as our code for setting the descriptors won't work if |
a306f2dd | 1290 | * ttyfd happens to be one of those. |
1291 | */ | |
b9a549d7 | 1292 | if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { |
1293 | dup2(fd, STDIN_FILENO); | |
1294 | dup2(fd, STDOUT_FILENO); | |
1295 | if (fd > STDOUT_FILENO) | |
1296 | close(fd); | |
1297 | } | |
5260325f | 1298 | debug("inetd sockets after dupping: %d, %d", sock_in, sock_out); |
b9a549d7 | 1299 | if ((options.protocol & SSH_PROTO_1) && |
1300 | sensitive_data.server_key == NULL) | |
cb7bd922 | 1301 | generate_ephemeral_server_key(); |
5260325f | 1302 | } else { |
48e671d5 | 1303 | for (ai = options.listen_addrs; ai; ai = ai->ai_next) { |
1304 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) | |
1305 | continue; | |
1306 | if (num_listen_socks >= MAX_LISTEN_SOCKS) | |
1307 | fatal("Too many listen sockets. " | |
1308 | "Enlarge MAX_LISTEN_SOCKS"); | |
945a9853 | 1309 | if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen, |
48e671d5 | 1310 | ntop, sizeof(ntop), strport, sizeof(strport), |
945a9853 | 1311 | NI_NUMERICHOST|NI_NUMERICSERV)) != 0) { |
1312 | error("getnameinfo failed: %.100s", | |
1313 | (ret != EAI_SYSTEM) ? gai_strerror(ret) : | |
1314 | strerror(errno)); | |
48e671d5 | 1315 | continue; |
1316 | } | |
1317 | /* Create socket for listening. */ | |
3e131a6d | 1318 | listen_sock = socket(ai->ai_family, ai->ai_socktype, |
1319 | ai->ai_protocol); | |
48e671d5 | 1320 | if (listen_sock < 0) { |
1321 | /* kernel may not support ipv6 */ | |
1322 | verbose("socket: %.100s", strerror(errno)); | |
1323 | continue; | |
1324 | } | |
170694d7 | 1325 | if (set_nonblock(listen_sock) == -1) { |
a666e3b1 | 1326 | close(listen_sock); |
1327 | continue; | |
1328 | } | |
48e671d5 | 1329 | /* |
facfd613 | 1330 | * Set socket options. |
1331 | * Allow local port reuse in TIME_WAIT. | |
48e671d5 | 1332 | */ |
facfd613 | 1333 | if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR, |
1334 | &on, sizeof(on)) == -1) | |
1335 | error("setsockopt SO_REUSEADDR: %s", strerror(errno)); | |
48e671d5 | 1336 | |
1337 | debug("Bind to port %s on %s.", strport, ntop); | |
1338 | ||
1339 | /* Bind the socket to the desired port. */ | |
32ced054 | 1340 | if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) { |
1341 | if (!ai->ai_next) | |
1342 | error("Bind to port %s on %s failed: %.200s.", | |
1343 | strport, ntop, strerror(errno)); | |
48e671d5 | 1344 | close(listen_sock); |
1345 | continue; | |
1346 | } | |
1347 | listen_socks[num_listen_socks] = listen_sock; | |
1348 | num_listen_socks++; | |
1349 | ||
1350 | /* Start listening on the port. */ | |
fce39749 | 1351 | if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0) |
9f513268 | 1352 | fatal("listen on [%s]:%s: %.100s", |
1353 | ntop, strport, strerror(errno)); | |
1354 | logit("Server listening on %s port %s.", ntop, strport); | |
5260325f | 1355 | } |
48e671d5 | 1356 | freeaddrinfo(options.listen_addrs); |
1357 | ||
1358 | if (!num_listen_socks) | |
1359 | fatal("Cannot bind any address."); | |
1360 | ||
3aca00a3 | 1361 | if (options.protocol & SSH_PROTO_1) |
1362 | generate_ephemeral_server_key(); | |
1363 | ||
1364 | /* | |
1365 | * Arrange to restart on SIGHUP. The handler needs | |
1366 | * listen_sock. | |
1367 | */ | |
1368 | signal(SIGHUP, sighup_handler); | |
1369 | ||
1370 | signal(SIGTERM, sigterm_handler); | |
1371 | signal(SIGQUIT, sigterm_handler); | |
1372 | ||
1373 | /* Arrange SIGCHLD to be caught. */ | |
1374 | signal(SIGCHLD, main_sigchld_handler); | |
1375 | ||
1376 | /* Write out the pid file after the sigterm handler is setup */ | |
5260325f | 1377 | if (!debug_flag) { |
aa3378df | 1378 | /* |
97fb6912 | 1379 | * Record our pid in /var/run/sshd.pid to make it |
1380 | * easier to kill the correct sshd. We don't want to | |
1381 | * do this before the bind above because the bind will | |
aa3378df | 1382 | * fail if there already is a daemon, and this will |
1383 | * overwrite any old pid in the file. | |
1384 | */ | |
3c62e7eb | 1385 | f = fopen(options.pid_file, "wb"); |
71b9ced0 | 1386 | if (f == NULL) { |
1387 | error("Couldn't create pid file \"%s\": %s", | |
1388 | options.pid_file, strerror(errno)); | |
1389 | } else { | |
c457707e | 1390 | fprintf(f, "%ld\n", (long) getpid()); |
5260325f | 1391 | fclose(f); |
1392 | } | |
8efc0c15 | 1393 | } |
5260325f | 1394 | |
48e671d5 | 1395 | /* setup fd set for listen */ |
089fbbd2 | 1396 | fdset = NULL; |
48e671d5 | 1397 | maxfd = 0; |
1398 | for (i = 0; i < num_listen_socks; i++) | |
1399 | if (listen_socks[i] > maxfd) | |
1400 | maxfd = listen_socks[i]; | |
089fbbd2 | 1401 | /* pipes connected to unauthenticated childs */ |
52e3daed | 1402 | startup_pipes = xcalloc(options.max_startups, sizeof(int)); |
089fbbd2 | 1403 | for (i = 0; i < options.max_startups; i++) |
1404 | startup_pipes[i] = -1; | |
48e671d5 | 1405 | |
aa3378df | 1406 | /* |
1407 | * Stay listening for connections until the system crashes or | |
1408 | * the daemon is killed with a signal. | |
1409 | */ | |
5260325f | 1410 | for (;;) { |
1411 | if (received_sighup) | |
1412 | sighup_restart(); | |
089fbbd2 | 1413 | if (fdset != NULL) |
1414 | xfree(fdset); | |
52e3daed | 1415 | fdset = (fd_set *)xcalloc(howmany(maxfd + 1, NFDBITS), |
1416 | sizeof(fd_mask)); | |
089fbbd2 | 1417 | |
48e671d5 | 1418 | for (i = 0; i < num_listen_socks; i++) |
1419 | FD_SET(listen_socks[i], fdset); | |
089fbbd2 | 1420 | for (i = 0; i < options.max_startups; i++) |
1421 | if (startup_pipes[i] != -1) | |
1422 | FD_SET(startup_pipes[i], fdset); | |
1423 | ||
1424 | /* Wait in select until there is a connection. */ | |
59c97189 | 1425 | ret = select(maxfd+1, fdset, NULL, NULL, NULL); |
1426 | if (ret < 0 && errno != EINTR) | |
1427 | error("select: %.100s", strerror(errno)); | |
c9130033 | 1428 | if (received_sigterm) { |
bbe88b6d | 1429 | logit("Received signal %d; terminating.", |
010f9726 | 1430 | (int) received_sigterm); |
c9130033 | 1431 | close_listen_socks(); |
1432 | unlink(options.pid_file); | |
1433 | exit(255); | |
1434 | } | |
59c97189 | 1435 | if (key_used && key_do_regen) { |
cb7bd922 | 1436 | generate_ephemeral_server_key(); |
59c97189 | 1437 | key_used = 0; |
1438 | key_do_regen = 0; | |
48e671d5 | 1439 | } |
59c97189 | 1440 | if (ret < 0) |
1441 | continue; | |
1442 | ||
089fbbd2 | 1443 | for (i = 0; i < options.max_startups; i++) |
1444 | if (startup_pipes[i] != -1 && | |
1445 | FD_ISSET(startup_pipes[i], fdset)) { | |
1446 | /* | |
1447 | * the read end of the pipe is ready | |
1448 | * if the child has closed the pipe | |
8abcdba4 | 1449 | * after successful authentication |
089fbbd2 | 1450 | * or if the child has died |
1451 | */ | |
1452 | close(startup_pipes[i]); | |
1453 | startup_pipes[i] = -1; | |
1454 | startups--; | |
1455 | } | |
48e671d5 | 1456 | for (i = 0; i < num_listen_socks; i++) { |
1457 | if (!FD_ISSET(listen_socks[i], fdset)) | |
5260325f | 1458 | continue; |
089fbbd2 | 1459 | fromlen = sizeof(from); |
3efa8ea9 | 1460 | newsock = accept(listen_socks[i], |
1461 | (struct sockaddr *)&from, &fromlen); | |
089fbbd2 | 1462 | if (newsock < 0) { |
1463 | if (errno != EINTR && errno != EWOULDBLOCK) | |
1464 | error("accept: %.100s", strerror(errno)); | |
1465 | continue; | |
1466 | } | |
170694d7 | 1467 | if (unset_nonblock(newsock) == -1) { |
a666e3b1 | 1468 | close(newsock); |
1469 | continue; | |
1470 | } | |
c345cf9d | 1471 | if (drop_connection(startups) == 1) { |
1472 | debug("drop connection #%d", startups); | |
089fbbd2 | 1473 | close(newsock); |
1474 | continue; | |
1475 | } | |
1476 | if (pipe(startup_p) == -1) { | |
1477 | close(newsock); | |
1478 | continue; | |
1479 | } | |
1480 | ||
b9a549d7 | 1481 | if (rexec_flag && socketpair(AF_UNIX, |
1482 | SOCK_STREAM, 0, config_s) == -1) { | |
1483 | error("reexec socketpair: %s", | |
1484 | strerror(errno)); | |
1485 | close(newsock); | |
1486 | close(startup_p[0]); | |
1487 | close(startup_p[1]); | |
1488 | continue; | |
1489 | } | |
1490 | ||
089fbbd2 | 1491 | for (j = 0; j < options.max_startups; j++) |
1492 | if (startup_pipes[j] == -1) { | |
1493 | startup_pipes[j] = startup_p[0]; | |
1494 | if (maxfd < startup_p[0]) | |
1495 | maxfd = startup_p[0]; | |
1496 | startups++; | |
1497 | break; | |
1498 | } | |
2b87da3b | 1499 | |
aa3378df | 1500 | /* |
089fbbd2 | 1501 | * Got connection. Fork a child to handle it, unless |
1502 | * we are in debugging mode. | |
aa3378df | 1503 | */ |
089fbbd2 | 1504 | if (debug_flag) { |
aa3378df | 1505 | /* |
089fbbd2 | 1506 | * In debugging mode. Close the listening |
1507 | * socket, and start processing the | |
1508 | * connection without forking. | |
aa3378df | 1509 | */ |
089fbbd2 | 1510 | debug("Server will not fork when running in debugging mode."); |
48e671d5 | 1511 | close_listen_socks(); |
5260325f | 1512 | sock_in = newsock; |
1513 | sock_out = newsock; | |
b9a549d7 | 1514 | close(startup_p[0]); |
1515 | close(startup_p[1]); | |
5540ea9b | 1516 | startup_pipe = -1; |
3f7a7e4a | 1517 | pid = getpid(); |
b9a549d7 | 1518 | if (rexec_flag) { |
1519 | send_rexec_state(config_s[0], | |
1520 | &cfg); | |
1521 | close(config_s[0]); | |
1522 | } | |
5260325f | 1523 | break; |
089fbbd2 | 1524 | } else { |
1525 | /* | |
1526 | * Normal production daemon. Fork, and have | |
1527 | * the child process the connection. The | |
1528 | * parent continues listening. | |
1529 | */ | |
1530 | if ((pid = fork()) == 0) { | |
1531 | /* | |
3efa8ea9 | 1532 | * Child. Close the listening and |
1533 | * max_startup sockets. Start using | |
1534 | * the accepted socket. Reinitialize | |
1535 | * logging (since our pid has changed). | |
1536 | * We break out of the loop to handle | |
089fbbd2 | 1537 | * the connection. |
1538 | */ | |
1539 | startup_pipe = startup_p[1]; | |
7ace8c3b | 1540 | close_startup_pipes(); |
089fbbd2 | 1541 | close_listen_socks(); |
1542 | sock_in = newsock; | |
1543 | sock_out = newsock; | |
3efa8ea9 | 1544 | log_init(__progname, |
1545 | options.log_level, | |
1546 | options.log_facility, | |
1547 | log_stderr); | |
9216f89c | 1548 | if (rexec_flag) |
1549 | close(config_s[0]); | |
089fbbd2 | 1550 | break; |
1551 | } | |
5260325f | 1552 | } |
5260325f | 1553 | |
089fbbd2 | 1554 | /* Parent. Stay in the loop. */ |
1555 | if (pid < 0) | |
1556 | error("fork: %.100s", strerror(errno)); | |
1557 | else | |
c457707e | 1558 | debug("Forked child %ld.", (long)pid); |
5260325f | 1559 | |
089fbbd2 | 1560 | close(startup_p[1]); |
5260325f | 1561 | |
b9a549d7 | 1562 | if (rexec_flag) { |
1563 | send_rexec_state(config_s[0], &cfg); | |
1564 | close(config_s[0]); | |
1565 | close(config_s[1]); | |
1566 | } | |
1567 | ||
3efa8ea9 | 1568 | /* |
1569 | * Mark that the key has been used (it | |
1570 | * was "given" to the child). | |
1571 | */ | |
59c97189 | 1572 | if ((options.protocol & SSH_PROTO_1) && |
1573 | key_used == 0) { | |
1574 | /* Schedule server key regeneration alarm. */ | |
f00d1f78 | 1575 | signal(SIGALRM, key_regeneration_alarm); |
59c97189 | 1576 | alarm(options.key_regeneration_time); |
1577 | key_used = 1; | |
1578 | } | |
5260325f | 1579 | |
089fbbd2 | 1580 | arc4random_stir(); |
089fbbd2 | 1581 | close(newsock); |
1582 | } | |
48e671d5 | 1583 | /* child process check (or debug mode) */ |
1584 | if (num_listen_socks < 0) | |
1585 | break; | |
5260325f | 1586 | } |
1587 | } | |
8efc0c15 | 1588 | |
5260325f | 1589 | /* This is the child processing a new connection. */ |
cc120685 | 1590 | setproctitle("%s", "[accepted]"); |
5260325f | 1591 | |
8b758bd2 | 1592 | /* |
1593 | * Create a new session and process group since the 4.4BSD | |
1594 | * setlogin() affects the entire process group. We don't | |
1595 | * want the child to be able to affect the parent. | |
1596 | */ | |
1597 | #if !defined(SSHD_ACQUIRES_CTTY) | |
1598 | /* | |
1599 | * If setsid is called, on some platforms sshd will later acquire a | |
1600 | * controlling terminal which will result in "could not set | |
1601 | * controlling tty" errors. | |
1602 | */ | |
1603 | if (!debug_flag && !inetd_flag && setsid() < 0) | |
1604 | error("setsid: %.100s", strerror(errno)); | |
1605 | #endif | |
1606 | ||
b9a549d7 | 1607 | if (rexec_flag) { |
1608 | int fd; | |
1609 | ||
b250e837 | 1610 | debug("rexec start in %d out %d newsock %d pipe %d sock %d", |
1611 | sock_in, sock_out, newsock, startup_pipe, config_s[0]); | |
b9a549d7 | 1612 | dup2(newsock, STDIN_FILENO); |
1613 | dup2(STDIN_FILENO, STDOUT_FILENO); | |
1614 | if (startup_pipe == -1) | |
b250e837 | 1615 | close(REEXEC_STARTUP_PIPE_FD); |
b9a549d7 | 1616 | else |
b250e837 | 1617 | dup2(startup_pipe, REEXEC_STARTUP_PIPE_FD); |
b9a549d7 | 1618 | |
b250e837 | 1619 | dup2(config_s[1], REEXEC_CONFIG_PASS_FD); |
b9a549d7 | 1620 | close(config_s[1]); |
ad148c04 | 1621 | if (startup_pipe != -1) |
1622 | close(startup_pipe); | |
b250e837 | 1623 | |
b9a549d7 | 1624 | execv(rexec_argv[0], rexec_argv); |
1625 | ||
1626 | /* Reexec has failed, fall back and continue */ | |
1627 | error("rexec of %s failed: %s", rexec_argv[0], strerror(errno)); | |
b250e837 | 1628 | recv_rexec_state(REEXEC_CONFIG_PASS_FD, NULL); |
b9a549d7 | 1629 | log_init(__progname, options.log_level, |
1630 | options.log_facility, log_stderr); | |
1631 | ||
1632 | /* Clean up fds */ | |
b250e837 | 1633 | startup_pipe = REEXEC_STARTUP_PIPE_FD; |
b9a549d7 | 1634 | close(config_s[1]); |
b250e837 | 1635 | close(REEXEC_CONFIG_PASS_FD); |
1636 | newsock = sock_out = sock_in = dup(STDIN_FILENO); | |
b9a549d7 | 1637 | if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { |
1638 | dup2(fd, STDIN_FILENO); | |
1639 | dup2(fd, STDOUT_FILENO); | |
1640 | if (fd > STDERR_FILENO) | |
1641 | close(fd); | |
1642 | } | |
b250e837 | 1643 | debug("rexec cleanup in %d out %d newsock %d pipe %d sock %d", |
1644 | sock_in, sock_out, newsock, startup_pipe, config_s[0]); | |
b9a549d7 | 1645 | } |
1646 | ||
aa3378df | 1647 | /* |
1648 | * Disable the key regeneration alarm. We will not regenerate the | |
1649 | * key since we are no longer in a position to give it to anyone. We | |
1650 | * will not restart on SIGHUP since it no longer makes sense. | |
1651 | */ | |
5260325f | 1652 | alarm(0); |
1653 | signal(SIGALRM, SIG_DFL); | |
1654 | signal(SIGHUP, SIG_DFL); | |
1655 | signal(SIGTERM, SIG_DFL); | |
1656 | signal(SIGQUIT, SIG_DFL); | |
1657 | signal(SIGCHLD, SIG_DFL); | |
9aaf9be4 | 1658 | signal(SIGINT, SIG_DFL); |
5260325f | 1659 | |
aa3378df | 1660 | /* |
1661 | * Register our connection. This turns encryption off because we do | |
1662 | * not have a key. | |
1663 | */ | |
5260325f | 1664 | packet_set_connection(sock_in, sock_out); |
07200973 | 1665 | packet_set_server(); |
5260325f | 1666 | |
7c3bc5a2 | 1667 | /* Set SO_KEEPALIVE if requested. */ |
1668 | if (options.tcp_keep_alive && packet_connection_is_on_socket() && | |
1669 | setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) < 0) | |
1670 | error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); | |
1671 | ||
29798ed0 | 1672 | if ((remote_port = get_remote_port()) < 0) { |
1673 | debug("get_remote_port failed"); | |
1674 | cleanup_exit(255); | |
1675 | } | |
3a85986d | 1676 | |
1677 | /* | |
1678 | * We use get_canonical_hostname with usedns = 0 instead of | |
1679 | * get_remote_ipaddr here so IP options will be checked. | |
1680 | */ | |
211f229e | 1681 | (void) get_canonical_hostname(0); |
1682 | /* | |
1683 | * The rest of the code depends on the fact that | |
1684 | * get_remote_ipaddr() caches the remote ip, even if | |
1685 | * the socket goes away. | |
1686 | */ | |
1687 | remote_ip = get_remote_ipaddr(); | |
5260325f | 1688 | |
6039eeef | 1689 | #ifdef SSH_AUDIT_EVENTS |
c00e4d75 | 1690 | audit_connection_from(remote_ip, remote_port); |
1691 | #endif | |
5260325f | 1692 | #ifdef LIBWRAP |
ac28afd8 | 1693 | /* Check whether logins are denied from this host. */ |
33e5359c | 1694 | if (packet_connection_is_on_socket()) { |
5260325f | 1695 | struct request_info req; |
8efc0c15 | 1696 | |
8fbc356d | 1697 | request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0); |
5260325f | 1698 | fromhost(&req); |
8efc0c15 | 1699 | |
5260325f | 1700 | if (!hosts_access(&req)) { |
ac28afd8 | 1701 | debug("Connection refused by tcp wrapper"); |
563834bb | 1702 | refuse(&req); |
ac28afd8 | 1703 | /* NOTREACHED */ |
1704 | fatal("libwrap refuse returns"); | |
5260325f | 1705 | } |
8efc0c15 | 1706 | } |
48e671d5 | 1707 | #endif /* LIBWRAP */ |
ac28afd8 | 1708 | |
5260325f | 1709 | /* Log the connection. */ |
1710 | verbose("Connection from %.500s port %d", remote_ip, remote_port); | |
8efc0c15 | 1711 | |
aa3378df | 1712 | /* |
7b9b0103 | 1713 | * We don't want to listen forever unless the other side |
aa3378df | 1714 | * successfully authenticates itself. So we set up an alarm which is |
1715 | * cleared after successful authentication. A limit of zero | |
7b9b0103 | 1716 | * indicates no limit. Note that we don't set the alarm in debugging |
aa3378df | 1717 | * mode; it is just annoying to have the server exit just when you |
1718 | * are about to discover the bug. | |
1719 | */ | |
f00d1f78 | 1720 | signal(SIGALRM, grace_alarm_handler); |
5260325f | 1721 | if (!debug_flag) |
1722 | alarm(options.login_grace_time); | |
1723 | ||
7368a6c8 | 1724 | sshd_exchange_identification(sock_in, sock_out); |
0598d99d | 1725 | |
5260325f | 1726 | packet_set_nonblocking(); |
1727 | ||
2362db19 | 1728 | /* allocate authentication context */ |
52e3daed | 1729 | authctxt = xcalloc(1, sizeof(*authctxt)); |
2362db19 | 1730 | |
1b394137 | 1731 | authctxt->loginmsg = &loginmsg; |
1732 | ||
2362db19 | 1733 | /* XXX global for cleanup, access from other modules */ |
1734 | the_authctxt = authctxt; | |
1735 | ||
022487ce | 1736 | /* prepare buffer to collect messages to display to user after login */ |
1737 | buffer_init(&loginmsg); | |
1738 | ||
324bf712 | 1739 | if (use_privsep) |
2362db19 | 1740 | if (privsep_preauth(authctxt) == 1) |
324bf712 | 1741 | goto authenticated; |
1853d1ef | 1742 | |
7b2ea3a1 | 1743 | /* perform the key exchange */ |
7b2ea3a1 | 1744 | /* authenticate user and start session */ |
e78a59f5 | 1745 | if (compat20) { |
1746 | do_ssh2_kex(); | |
2362db19 | 1747 | do_authentication2(authctxt); |
e78a59f5 | 1748 | } else { |
1749 | do_ssh1_kex(); | |
2362db19 | 1750 | do_authentication(authctxt); |
e78a59f5 | 1751 | } |
324bf712 | 1752 | /* |
1753 | * If we use privilege separation, the unprivileged child transfers | |
1754 | * the current keystate and exits | |
1755 | */ | |
1756 | if (use_privsep) { | |
b5a28cbc | 1757 | mm_send_keystate(pmonitor); |
1853d1ef | 1758 | exit(0); |
324bf712 | 1759 | } |
1853d1ef | 1760 | |
1761 | authenticated: | |
678143bd | 1762 | /* |
1763 | * Cancel the alarm we set to limit the time taken for | |
1764 | * authentication. | |
1765 | */ | |
1766 | alarm(0); | |
1767 | signal(SIGALRM, SIG_DFL); | |
1768 | if (startup_pipe != -1) { | |
1769 | close(startup_pipe); | |
1770 | startup_pipe = -1; | |
1771 | } | |
1772 | ||
6039eeef | 1773 | #ifdef SSH_AUDIT_EVENTS |
1774 | audit_event(SSH_AUTH_SUCCESS); | |
c00e4d75 | 1775 | #endif |
1776 | ||
762715ce | 1777 | /* |
1853d1ef | 1778 | * In privilege separation, we fork another child and prepare |
1779 | * file descriptor passing. | |
1780 | */ | |
1781 | if (use_privsep) { | |
324bf712 | 1782 | privsep_postauth(authctxt); |
1783 | /* the monitor process [priv] will not return */ | |
1853d1ef | 1784 | if (!compat20) |
1785 | destroy_sensitive_data(); | |
1786 | } | |
1b34c1b3 | 1787 | |
2362db19 | 1788 | /* Start session. */ |
1b34c1b3 | 1789 | do_authenticated(authctxt); |
1790 | ||
63284fbb | 1791 | /* The connection has been terminated. */ |
1792 | verbose("Closing connection to %.100s", remote_ip); | |
8efc0c15 | 1793 | |
d94aa2ae | 1794 | #ifdef USE_PAM |
7fceb20d | 1795 | if (options.use_pam) |
1796 | finish_pam(); | |
d94aa2ae | 1797 | #endif /* USE_PAM */ |
8efc0c15 | 1798 | |
2b0c0925 | 1799 | #ifdef SSH_AUDIT_EVENTS |
1800 | PRIVSEP(audit_event(SSH_CONNECTION_CLOSE)); | |
1801 | #endif | |
1802 | ||
5260325f | 1803 | packet_close(); |
1853d1ef | 1804 | |
1805 | if (use_privsep) | |
1806 | mm_terminate(); | |
1807 | ||
5260325f | 1808 | exit(0); |
1809 | } | |
8efc0c15 | 1810 | |
4f08e98d | 1811 | /* |
1812 | * Decrypt session_key_int using our private server key and private host key | |
1813 | * (key with larger modulus first). | |
1814 | */ | |
1853d1ef | 1815 | int |
4f08e98d | 1816 | ssh1_session_key(BIGNUM *session_key_int) |
1817 | { | |
1818 | int rsafail = 0; | |
1819 | ||
3efa8ea9 | 1820 | if (BN_cmp(sensitive_data.server_key->rsa->n, |
1821 | sensitive_data.ssh1_host_key->rsa->n) > 0) { | |
4f08e98d | 1822 | /* Server key has bigger modulus. */ |
1823 | if (BN_num_bits(sensitive_data.server_key->rsa->n) < | |
3efa8ea9 | 1824 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + |
1825 | SSH_KEY_BITS_RESERVED) { | |
1826 | fatal("do_connection: %s: " | |
1827 | "server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d", | |
4f08e98d | 1828 | get_remote_ipaddr(), |
1829 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
1830 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), | |
1831 | SSH_KEY_BITS_RESERVED); | |
1832 | } | |
1833 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1834 | sensitive_data.server_key->rsa) <= 0) | |
1835 | rsafail++; | |
1836 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1837 | sensitive_data.ssh1_host_key->rsa) <= 0) | |
1838 | rsafail++; | |
1839 | } else { | |
1840 | /* Host key has bigger modulus (or they are equal). */ | |
1841 | if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) < | |
3efa8ea9 | 1842 | BN_num_bits(sensitive_data.server_key->rsa->n) + |
1843 | SSH_KEY_BITS_RESERVED) { | |
1844 | fatal("do_connection: %s: " | |
1845 | "host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d", | |
4f08e98d | 1846 | get_remote_ipaddr(), |
1847 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), | |
1848 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
1849 | SSH_KEY_BITS_RESERVED); | |
1850 | } | |
1851 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1852 | sensitive_data.ssh1_host_key->rsa) < 0) | |
1853 | rsafail++; | |
1854 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1855 | sensitive_data.server_key->rsa) < 0) | |
1856 | rsafail++; | |
1857 | } | |
1858 | return (rsafail); | |
1859 | } | |
5260325f | 1860 | /* |
7b2ea3a1 | 1861 | * SSH1 key exchange |
5260325f | 1862 | */ |
396c147e | 1863 | static void |
1e3b8b07 | 1864 | do_ssh1_kex(void) |
8efc0c15 | 1865 | { |
5260325f | 1866 | int i, len; |
46aa2d1f | 1867 | int rsafail = 0; |
5260325f | 1868 | BIGNUM *session_key_int; |
1e3b8b07 | 1869 | u_char session_key[SSH_SESSION_KEY_LENGTH]; |
1870 | u_char cookie[8]; | |
1871 | u_int cipher_type, auth_mask, protocol_flags; | |
7fdc56c5 | 1872 | u_int32_t rnd = 0; |
5260325f | 1873 | |
aa3378df | 1874 | /* |
1875 | * Generate check bytes that the client must send back in the user | |
1876 | * packet in order for it to be accepted; this is used to defy ip | |
1877 | * spoofing attacks. Note that this only works against somebody | |
1878 | * doing IP spoofing from a remote machine; any machine on the local | |
1879 | * network can still see outgoing packets and catch the random | |
1880 | * cookie. This only affects rhosts authentication, and this is one | |
1881 | * of the reasons why it is inherently insecure. | |
1882 | */ | |
5260325f | 1883 | for (i = 0; i < 8; i++) { |
1884 | if (i % 4 == 0) | |
7fdc56c5 | 1885 | rnd = arc4random(); |
1886 | cookie[i] = rnd & 0xff; | |
1887 | rnd >>= 8; | |
5260325f | 1888 | } |
1889 | ||
aa3378df | 1890 | /* |
1891 | * Send our public key. We include in the packet 64 bits of random | |
1892 | * data that must be matched in the reply in order to prevent IP | |
1893 | * spoofing. | |
1894 | */ | |
5260325f | 1895 | packet_start(SSH_SMSG_PUBLIC_KEY); |
1896 | for (i = 0; i < 8; i++) | |
7b2ea3a1 | 1897 | packet_put_char(cookie[i]); |
5260325f | 1898 | |
1899 | /* Store our public server RSA key. */ | |
fa08c86b | 1900 | packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n)); |
1901 | packet_put_bignum(sensitive_data.server_key->rsa->e); | |
1902 | packet_put_bignum(sensitive_data.server_key->rsa->n); | |
5260325f | 1903 | |
1904 | /* Store our public host RSA key. */ | |
fa08c86b | 1905 | packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); |
1906 | packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e); | |
1907 | packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n); | |
5260325f | 1908 | |
1909 | /* Put protocol flags. */ | |
1910 | packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN); | |
1911 | ||
1912 | /* Declare which ciphers we support. */ | |
94ec8c6b | 1913 | packet_put_int(cipher_mask_ssh1(0)); |
5260325f | 1914 | |
1915 | /* Declare supported authentication types. */ | |
1916 | auth_mask = 0; | |
5260325f | 1917 | if (options.rhosts_rsa_authentication) |
1918 | auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA; | |
1919 | if (options.rsa_authentication) | |
1920 | auth_mask |= 1 << SSH_AUTH_RSA; | |
5ba55ada | 1921 | if (options.challenge_response_authentication == 1) |
5260325f | 1922 | auth_mask |= 1 << SSH_AUTH_TIS; |
5260325f | 1923 | if (options.password_authentication) |
1924 | auth_mask |= 1 << SSH_AUTH_PASSWORD; | |
1925 | packet_put_int(auth_mask); | |
1926 | ||
1927 | /* Send the packet and wait for it to be sent. */ | |
1928 | packet_send(); | |
1929 | packet_write_wait(); | |
1930 | ||
fa08c86b | 1931 | debug("Sent %d bit server key and %d bit host key.", |
1932 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
1933 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); | |
5260325f | 1934 | |
1935 | /* Read clients reply (cipher type and session key). */ | |
54a5250f | 1936 | packet_read_expect(SSH_CMSG_SESSION_KEY); |
5260325f | 1937 | |
2d86a6cc | 1938 | /* Get cipher type and check whether we accept this. */ |
5260325f | 1939 | cipher_type = packet_get_char(); |
1940 | ||
94ec8c6b | 1941 | if (!(cipher_mask_ssh1(0) & (1 << cipher_type))) |
2d86a6cc | 1942 | packet_disconnect("Warning: client selects unsupported cipher."); |
1943 | ||
5260325f | 1944 | /* Get check bytes from the packet. These must match those we |
1945 | sent earlier with the public key packet. */ | |
1946 | for (i = 0; i < 8; i++) | |
7b2ea3a1 | 1947 | if (cookie[i] != packet_get_char()) |
5260325f | 1948 | packet_disconnect("IP Spoofing check bytes do not match."); |
1949 | ||
1950 | debug("Encryption type: %.200s", cipher_name(cipher_type)); | |
1951 | ||
1952 | /* Get the encrypted integer. */ | |
b775c6f2 | 1953 | if ((session_key_int = BN_new()) == NULL) |
1954 | fatal("do_ssh1_kex: BN_new failed"); | |
20b279e6 | 1955 | packet_get_bignum(session_key_int); |
5260325f | 1956 | |
5260325f | 1957 | protocol_flags = packet_get_int(); |
1958 | packet_set_protocol_flags(protocol_flags); | |
95500969 | 1959 | packet_check_eom(); |
5260325f | 1960 | |
4f08e98d | 1961 | /* Decrypt session_key_int using host/server keys */ |
1853d1ef | 1962 | rsafail = PRIVSEP(ssh1_session_key(session_key_int)); |
1963 | ||
aa3378df | 1964 | /* |
1965 | * Extract session key from the decrypted integer. The key is in the | |
1966 | * least significant 256 bits of the integer; the first byte of the | |
1967 | * key is in the highest bits. | |
1968 | */ | |
46aa2d1f | 1969 | if (!rsafail) { |
1970 | BN_mask_bits(session_key_int, sizeof(session_key) * 8); | |
1971 | len = BN_num_bytes(session_key_int); | |
2ceb8101 | 1972 | if (len < 0 || (u_int)len > sizeof(session_key)) { |
46aa2d1f | 1973 | error("do_connection: bad session key len from %s: " |
5ca51e19 | 1974 | "session_key_int %d > sizeof(session_key) %lu", |
1975 | get_remote_ipaddr(), len, (u_long)sizeof(session_key)); | |
46aa2d1f | 1976 | rsafail++; |
1977 | } else { | |
1978 | memset(session_key, 0, sizeof(session_key)); | |
1979 | BN_bn2bin(session_key_int, | |
1980 | session_key + sizeof(session_key) - len); | |
00be5382 | 1981 | |
8bbf1fa6 | 1982 | derive_ssh1_session_id( |
f2107e97 | 1983 | sensitive_data.ssh1_host_key->rsa->n, |
8bbf1fa6 | 1984 | sensitive_data.server_key->rsa->n, |
1985 | cookie, session_id); | |
00be5382 | 1986 | /* |
1987 | * Xor the first 16 bytes of the session key with the | |
1988 | * session id. | |
1989 | */ | |
1990 | for (i = 0; i < 16; i++) | |
1991 | session_key[i] ^= session_id[i]; | |
46aa2d1f | 1992 | } |
1993 | } | |
1994 | if (rsafail) { | |
00be5382 | 1995 | int bytes = BN_num_bytes(session_key_int); |
f6b1ba8f | 1996 | u_char *buf = xmalloc(bytes); |
00be5382 | 1997 | MD5_CTX md; |
1998 | ||
bbe88b6d | 1999 | logit("do_connection: generating a fake encryption key"); |
00be5382 | 2000 | BN_bn2bin(session_key_int, buf); |
2001 | MD5_Init(&md); | |
2002 | MD5_Update(&md, buf, bytes); | |
2003 | MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); | |
2004 | MD5_Final(session_key, &md); | |
2005 | MD5_Init(&md); | |
2006 | MD5_Update(&md, session_key, 16); | |
2007 | MD5_Update(&md, buf, bytes); | |
2008 | MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); | |
2009 | MD5_Final(session_key + 16, &md); | |
2010 | memset(buf, 0, bytes); | |
2011 | xfree(buf); | |
0572fe75 | 2012 | for (i = 0; i < 16; i++) |
2013 | session_id[i] = session_key[i] ^ session_key[i + 16]; | |
46aa2d1f | 2014 | } |
1853d1ef | 2015 | /* Destroy the private and public keys. No longer. */ |
63284fbb | 2016 | destroy_sensitive_data(); |
00be5382 | 2017 | |
1853d1ef | 2018 | if (use_privsep) |
2019 | mm_ssh1_session_id(session_id); | |
2020 | ||
7b2ea3a1 | 2021 | /* Destroy the decrypted integer. It is no longer needed. */ |
2022 | BN_clear_free(session_key_int); | |
2023 | ||
5260325f | 2024 | /* Set the session key. From this on all communications will be encrypted. */ |
2025 | packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type); | |
2026 | ||
2027 | /* Destroy our copy of the session key. It is no longer needed. */ | |
2028 | memset(session_key, 0, sizeof(session_key)); | |
2029 | ||
2030 | debug("Received session key; encryption turned on."); | |
2031 | ||
c242fc96 | 2032 | /* Send an acknowledgment packet. Note that this packet is sent encrypted. */ |
5260325f | 2033 | packet_start(SSH_SMSG_SUCCESS); |
2034 | packet_send(); | |
2035 | packet_write_wait(); | |
5260325f | 2036 | } |
e78a59f5 | 2037 | |
2038 | /* | |
2039 | * SSH2 key exchange: diffie-hellman-group1-sha1 | |
2040 | */ | |
396c147e | 2041 | static void |
1e3b8b07 | 2042 | do_ssh2_kex(void) |
e78a59f5 | 2043 | { |
e78a59f5 | 2044 | Kex *kex; |
e78a59f5 | 2045 | |
a8be9f80 | 2046 | if (options.ciphers != NULL) { |
6ae2364d | 2047 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = |
a8be9f80 | 2048 | myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; |
2049 | } | |
1ad64a93 | 2050 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = |
2051 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]); | |
2052 | myproposal[PROPOSAL_ENC_ALGS_STOC] = | |
2053 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); | |
2054 | ||
b2552997 | 2055 | if (options.macs != NULL) { |
2056 | myproposal[PROPOSAL_MAC_ALGS_CTOS] = | |
2057 | myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; | |
2058 | } | |
07200973 | 2059 | if (options.compression == COMP_NONE) { |
636f76ca | 2060 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = |
2061 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "none"; | |
07200973 | 2062 | } else if (options.compression == COMP_DELAYED) { |
2063 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = | |
2064 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com"; | |
636f76ca | 2065 | } |
3efa8ea9 | 2066 | |
fa08c86b | 2067 | myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = list_hostkey_types(); |
2068 | ||
7a37c112 | 2069 | /* start key exchange */ |
d8ee838b | 2070 | kex = kex_setup(myproposal); |
98a58eda | 2071 | kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server; |
41e5bd9a | 2072 | kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server; |
98a58eda | 2073 | kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; |
2ff8003a | 2074 | kex->kex[KEX_DH_GEX_SHA256] = kexgex_server; |
a5c9ffdb | 2075 | kex->server = 1; |
2076 | kex->client_version_string=client_version_string; | |
2077 | kex->server_version_string=server_version_string; | |
2078 | kex->load_host_key=&get_hostkey_by_type; | |
1853d1ef | 2079 | kex->host_key_index=&get_hostkey_index; |
94ec8c6b | 2080 | |
7a37c112 | 2081 | xxx_kex = kex; |
2082 | ||
c422989b | 2083 | dispatch_run(DISPATCH_BLOCK, &kex->done, kex); |
94ec8c6b | 2084 | |
d1ac6175 | 2085 | session_id2 = kex->session_id; |
2086 | session_id2_len = kex->session_id_len; | |
2087 | ||
94ec8c6b | 2088 | #ifdef DEBUG_KEXDH |
2089 | /* send 1st encrypted/maced/compressed message */ | |
2090 | packet_start(SSH2_MSG_IGNORE); | |
2091 | packet_put_cstring("markus"); | |
2092 | packet_send(); | |
2093 | packet_write_wait(); | |
2094 | #endif | |
a5c9ffdb | 2095 | debug("KEX done"); |
e78a59f5 | 2096 | } |
2362db19 | 2097 | |
2098 | /* server specific fatal cleanup */ | |
2099 | void | |
2100 | cleanup_exit(int i) | |
2101 | { | |
2102 | if (the_authctxt) | |
2103 | do_cleanup(the_authctxt); | |
6039eeef | 2104 | #ifdef SSH_AUDIT_EVENTS |
c00e4d75 | 2105 | /* done after do_cleanup so it can cancel the PAM auth 'thread' */ |
2106 | if (!use_privsep || mm_is_monitor()) | |
6039eeef | 2107 | audit_event(SSH_CONNECTION_ABANDON); |
c00e4d75 | 2108 | #endif |
2362db19 | 2109 | _exit(i); |
2110 | } |