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184cb418 | 1 | /* $OpenBSD: sshd.c,v 1.347 2006/08/18 09:15:20 markus 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> |
31652869 | 48 | #include <sys/ioctl.h> |
49 | #include <sys/socket.h> | |
4095f623 | 50 | #ifdef HAVE_SYS_STAT_H |
51 | # include <sys/stat.h> | |
52 | #endif | |
e264ac72 | 53 | #ifdef HAVE_SYS_TIME_H |
54 | # include <sys/time.h> | |
55 | #endif | |
31652869 | 56 | #include "openbsd-compat/sys-tree.h" |
aa2eae64 | 57 | #include <sys/wait.h> |
a75f5360 | 58 | |
028094f4 | 59 | #include <errno.h> |
d3221cca | 60 | #include <fcntl.h> |
28cb0a43 | 61 | #include <netdb.h> |
b5b88c19 | 62 | #ifdef HAVE_PATHS_H |
a75f5360 | 63 | #include <paths.h> |
b5b88c19 | 64 | #endif |
22bbb3e6 | 65 | #include <grp.h> |
b1842393 | 66 | #include <pwd.h> |
ada68823 | 67 | #include <signal.h> |
24436b92 | 68 | #include <stdarg.h> |
cf851879 | 69 | #include <stdio.h> |
ffa517a8 | 70 | #include <stdlib.h> |
00146caa | 71 | #include <string.h> |
00a017bd | 72 | #include <unistd.h> |
8efc0c15 | 73 | |
42f11eb2 | 74 | #include <openssl/dh.h> |
75 | #include <openssl/bn.h> | |
436c347c | 76 | #include <openssl/md5.h> |
1853d1ef | 77 | #include <openssl/rand.h> |
6e879cb4 | 78 | #ifdef HAVE_SECUREWARE |
79 | #include <sys/security.h> | |
80 | #include <prot.h> | |
81 | #endif | |
42f11eb2 | 82 | |
31652869 | 83 | #include "xmalloc.h" |
42f11eb2 | 84 | #include "ssh.h" |
85 | #include "ssh1.h" | |
86 | #include "ssh2.h" | |
8efc0c15 | 87 | #include "rsa.h" |
1729c161 | 88 | #include "sshpty.h" |
8efc0c15 | 89 | #include "packet.h" |
42f11eb2 | 90 | #include "log.h" |
31652869 | 91 | #include "buffer.h" |
8efc0c15 | 92 | #include "servconf.h" |
93 | #include "uidswap.h" | |
94 | #include "compat.h" | |
42f11eb2 | 95 | #include "cipher.h" |
7368a6c8 | 96 | #include "key.h" |
31652869 | 97 | #include "kex.h" |
94ec8c6b | 98 | #include "dh.h" |
e78a59f5 | 99 | #include "myproposal.h" |
a306f2dd | 100 | #include "authfile.h" |
42f11eb2 | 101 | #include "pathnames.h" |
102 | #include "atomicio.h" | |
103 | #include "canohost.h" | |
31652869 | 104 | #include "hostfile.h" |
42f11eb2 | 105 | #include "auth.h" |
106 | #include "misc.h" | |
b9a549d7 | 107 | #include "msg.h" |
a5c9ffdb | 108 | #include "dispatch.h" |
e4d7f734 | 109 | #include "channels.h" |
1b34c1b3 | 110 | #include "session.h" |
1853d1ef | 111 | #include "monitor_mm.h" |
112 | #include "monitor.h" | |
31652869 | 113 | #ifdef GSSAPI |
114 | #include "ssh-gss.h" | |
115 | #endif | |
1853d1ef | 116 | #include "monitor_wrap.h" |
117 | #include "monitor_fdpass.h" | |
28015df4 | 118 | #include "version.h" |
8efc0c15 | 119 | |
120 | #ifdef LIBWRAP | |
121 | #include <tcpd.h> | |
122 | #include <syslog.h> | |
123 | int allow_severity = LOG_INFO; | |
124 | int deny_severity = LOG_WARNING; | |
125 | #endif /* LIBWRAP */ | |
126 | ||
127 | #ifndef O_NOCTTY | |
128 | #define O_NOCTTY 0 | |
129 | #endif | |
130 | ||
b250e837 | 131 | /* Re-exec fds */ |
132 | #define REEXEC_DEVCRYPTO_RESERVED_FD (STDERR_FILENO + 1) | |
133 | #define REEXEC_STARTUP_PIPE_FD (STDERR_FILENO + 2) | |
134 | #define REEXEC_CONFIG_PASS_FD (STDERR_FILENO + 3) | |
135 | #define REEXEC_MIN_FREE_FD (STDERR_FILENO + 4) | |
136 | ||
260d427b | 137 | extern char *__progname; |
260d427b | 138 | |
8efc0c15 | 139 | /* Server configuration options. */ |
140 | ServerOptions options; | |
141 | ||
142 | /* Name of the server configuration file. */ | |
42f11eb2 | 143 | char *config_file_name = _PATH_SERVER_CONFIG_FILE; |
8efc0c15 | 144 | |
5260325f | 145 | /* |
146 | * Debug mode flag. This can be set on the command line. If debug | |
147 | * mode is enabled, extra debugging output will be sent to the system | |
148 | * log, the daemon will not go to background, and will exit after processing | |
149 | * the first connection. | |
150 | */ | |
8efc0c15 | 151 | int debug_flag = 0; |
152 | ||
f87f09aa | 153 | /* Flag indicating that the daemon should only test the configuration and keys. */ |
154 | int test_flag = 0; | |
155 | ||
8efc0c15 | 156 | /* Flag indicating that the daemon is being started from inetd. */ |
157 | int inetd_flag = 0; | |
158 | ||
0b6fbf03 | 159 | /* Flag indicating that sshd should not detach and become a daemon. */ |
160 | int no_daemon_flag = 0; | |
161 | ||
6a17f9c2 | 162 | /* debug goes to stderr unless inetd_flag is set */ |
163 | int log_stderr = 0; | |
164 | ||
8efc0c15 | 165 | /* Saved arguments to main(). */ |
166 | char **saved_argv; | |
4d33e531 | 167 | int saved_argc; |
8efc0c15 | 168 | |
b9a549d7 | 169 | /* re-exec */ |
170 | int rexeced_flag = 0; | |
171 | int rexec_flag = 1; | |
172 | int rexec_argc = 0; | |
173 | char **rexec_argv; | |
174 | ||
aa3378df | 175 | /* |
48e671d5 | 176 | * The sockets that the server is listening; this is used in the SIGHUP |
177 | * signal handler. | |
aa3378df | 178 | */ |
48e671d5 | 179 | #define MAX_LISTEN_SOCKS 16 |
180 | int listen_socks[MAX_LISTEN_SOCKS]; | |
181 | int num_listen_socks = 0; | |
8efc0c15 | 182 | |
aa3378df | 183 | /* |
184 | * the client's version string, passed by sshd2 in compat mode. if != NULL, | |
185 | * sshd will skip the version-number exchange | |
186 | */ | |
5260325f | 187 | char *client_version_string = NULL; |
7368a6c8 | 188 | char *server_version_string = NULL; |
8efc0c15 | 189 | |
7a37c112 | 190 | /* for rekeying XXX fixme */ |
191 | Kex *xxx_kex; | |
192 | ||
aa3378df | 193 | /* |
194 | * Any really sensitive data in the application is contained in this | |
195 | * structure. The idea is that this structure could be locked into memory so | |
196 | * that the pages do not get written into swap. However, there are some | |
197 | * problems. The private key contains BIGNUMs, and we do not (in principle) | |
198 | * have access to the internals of them, and locking just the structure is | |
199 | * not very useful. Currently, memory locking is not implemented. | |
200 | */ | |
5260325f | 201 | struct { |
cb7bd922 | 202 | Key *server_key; /* ephemeral server key */ |
fa08c86b | 203 | Key *ssh1_host_key; /* ssh1 host key */ |
204 | Key **host_keys; /* all private host keys */ | |
205 | int have_ssh1_key; | |
206 | int have_ssh2_key; | |
00be5382 | 207 | u_char ssh1_cookie[SSH_SESSION_KEY_LENGTH]; |
8efc0c15 | 208 | } sensitive_data; |
209 | ||
aa3378df | 210 | /* |
59c97189 | 211 | * Flag indicating whether the RSA server key needs to be regenerated. |
212 | * Is set in the SIGALRM handler and cleared when the key is regenerated. | |
aa3378df | 213 | */ |
7a934d1b | 214 | static volatile sig_atomic_t key_do_regen = 0; |
8efc0c15 | 215 | |
c9130033 | 216 | /* This is set to true when a signal is received. */ |
7a934d1b | 217 | static volatile sig_atomic_t received_sighup = 0; |
218 | static volatile sig_atomic_t received_sigterm = 0; | |
8efc0c15 | 219 | |
7368a6c8 | 220 | /* session identifier, used by RSA-auth */ |
1e3b8b07 | 221 | u_char session_id[16]; |
e7c0f9d5 | 222 | |
a306f2dd | 223 | /* same for ssh2 */ |
1e3b8b07 | 224 | u_char *session_id2 = NULL; |
a27002e5 | 225 | u_int session_id2_len = 0; |
a306f2dd | 226 | |
c345cf9d | 227 | /* record remote hostname or ip */ |
1e3b8b07 | 228 | u_int utmp_len = MAXHOSTNAMELEN; |
c345cf9d | 229 | |
7ace8c3b | 230 | /* options.max_startup sized array of fd ints */ |
231 | int *startup_pipes = NULL; | |
232 | int startup_pipe; /* in child */ | |
233 | ||
1853d1ef | 234 | /* variables used for privilege separation */ |
d231781a | 235 | int use_privsep = -1; |
a9b33b95 | 236 | struct monitor *pmonitor = NULL; |
1853d1ef | 237 | |
2362db19 | 238 | /* global authentication context */ |
239 | Authctxt *the_authctxt = NULL; | |
240 | ||
d231781a | 241 | /* sshd_config buffer */ |
242 | Buffer cfg; | |
243 | ||
be2ca0c9 | 244 | /* message to be displayed after login */ |
245 | Buffer loginmsg; | |
246 | ||
7368a6c8 | 247 | /* Prototypes for various functions defined later in this file. */ |
396c147e | 248 | void destroy_sensitive_data(void); |
1853d1ef | 249 | void demote_sensitive_data(void); |
c8d54615 | 250 | |
396c147e | 251 | static void do_ssh1_kex(void); |
252 | static void do_ssh2_kex(void); | |
94ec8c6b | 253 | |
48e671d5 | 254 | /* |
255 | * Close all listening sockets | |
256 | */ | |
396c147e | 257 | static void |
48e671d5 | 258 | close_listen_socks(void) |
259 | { | |
260 | int i; | |
e424e241 | 261 | |
48e671d5 | 262 | for (i = 0; i < num_listen_socks; i++) |
263 | close(listen_socks[i]); | |
264 | num_listen_socks = -1; | |
265 | } | |
266 | ||
7ace8c3b | 267 | static void |
268 | close_startup_pipes(void) | |
269 | { | |
270 | int i; | |
e424e241 | 271 | |
7ace8c3b | 272 | if (startup_pipes) |
273 | for (i = 0; i < options.max_startups; i++) | |
274 | if (startup_pipes[i] != -1) | |
275 | close(startup_pipes[i]); | |
276 | } | |
277 | ||
5260325f | 278 | /* |
279 | * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP; | |
280 | * the effect is to reread the configuration file (and to regenerate | |
281 | * the server key). | |
282 | */ | |
3efa8ea9 | 283 | |
284 | /*ARGSUSED*/ | |
396c147e | 285 | static void |
5260325f | 286 | sighup_handler(int sig) |
8efc0c15 | 287 | { |
6056eb35 | 288 | int save_errno = errno; |
289 | ||
5260325f | 290 | received_sighup = 1; |
291 | signal(SIGHUP, sighup_handler); | |
6056eb35 | 292 | errno = save_errno; |
8efc0c15 | 293 | } |
294 | ||
5260325f | 295 | /* |
296 | * Called from the main program after receiving SIGHUP. | |
297 | * Restarts the server. | |
298 | */ | |
396c147e | 299 | static void |
5ca51e19 | 300 | sighup_restart(void) |
8efc0c15 | 301 | { |
bbe88b6d | 302 | logit("Received SIGHUP; restarting."); |
48e671d5 | 303 | close_listen_socks(); |
7ace8c3b | 304 | close_startup_pipes(); |
5260325f | 305 | execv(saved_argv[0], saved_argv); |
bbe88b6d | 306 | logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0], |
e424e241 | 307 | strerror(errno)); |
5260325f | 308 | exit(1); |
8efc0c15 | 309 | } |
310 | ||
5260325f | 311 | /* |
312 | * Generic signal handler for terminating signals in the master daemon. | |
5260325f | 313 | */ |
3efa8ea9 | 314 | /*ARGSUSED*/ |
396c147e | 315 | static void |
5260325f | 316 | sigterm_handler(int sig) |
8efc0c15 | 317 | { |
c9130033 | 318 | received_sigterm = sig; |
8efc0c15 | 319 | } |
320 | ||
5260325f | 321 | /* |
322 | * SIGCHLD handler. This is called whenever a child dies. This will then | |
c9130033 | 323 | * reap any zombies left by exited children. |
5260325f | 324 | */ |
3efa8ea9 | 325 | /*ARGSUSED*/ |
396c147e | 326 | static void |
5260325f | 327 | main_sigchld_handler(int sig) |
8efc0c15 | 328 | { |
5260325f | 329 | int save_errno = errno; |
e424e241 | 330 | pid_t pid; |
5260325f | 331 | int status; |
5ad13cd7 | 332 | |
8c38e88b | 333 | while ((pid = waitpid(-1, &status, WNOHANG)) > 0 || |
334 | (pid < 0 && errno == EINTR)) | |
5260325f | 335 | ; |
5ad13cd7 | 336 | |
5260325f | 337 | signal(SIGCHLD, main_sigchld_handler); |
338 | errno = save_errno; | |
8efc0c15 | 339 | } |
340 | ||
5260325f | 341 | /* |
342 | * Signal handler for the alarm after the login grace period has expired. | |
343 | */ | |
3efa8ea9 | 344 | /*ARGSUSED*/ |
396c147e | 345 | static void |
5260325f | 346 | grace_alarm_handler(int sig) |
8efc0c15 | 347 | { |
a9b33b95 | 348 | if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0) |
349 | kill(pmonitor->m_pid, SIGALRM); | |
350 | ||
5260325f | 351 | /* Log error and exit. */ |
28463427 | 352 | sigdie("Timeout before authentication for %s", get_remote_ipaddr()); |
5260325f | 353 | } |
8efc0c15 | 354 | |
5260325f | 355 | /* |
356 | * Signal handler for the key regeneration alarm. Note that this | |
357 | * alarm only occurs in the daemon waiting for connections, and it does not | |
358 | * do anything with the private key or random state before forking. | |
359 | * Thus there should be no concurrency control/asynchronous execution | |
360 | * problems. | |
361 | */ | |
396c147e | 362 | static void |
cb7bd922 | 363 | generate_ephemeral_server_key(void) |
fa08c86b | 364 | { |
7fdc56c5 | 365 | u_int32_t rnd = 0; |
00be5382 | 366 | int i; |
367 | ||
cd332296 | 368 | verbose("Generating %s%d bit RSA key.", |
76ca7b01 | 369 | sensitive_data.server_key ? "new " : "", options.server_key_bits); |
fa08c86b | 370 | if (sensitive_data.server_key != NULL) |
371 | key_free(sensitive_data.server_key); | |
cd332296 | 372 | sensitive_data.server_key = key_generate(KEY_RSA1, |
76ca7b01 | 373 | options.server_key_bits); |
374 | verbose("RSA key generation complete."); | |
00be5382 | 375 | |
376 | for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) { | |
377 | if (i % 4 == 0) | |
7fdc56c5 | 378 | rnd = arc4random(); |
379 | sensitive_data.ssh1_cookie[i] = rnd & 0xff; | |
380 | rnd >>= 8; | |
00be5382 | 381 | } |
382 | arc4random_stir(); | |
fa08c86b | 383 | } |
f546c780 | 384 | |
3efa8ea9 | 385 | /*ARGSUSED*/ |
396c147e | 386 | static void |
5260325f | 387 | key_regeneration_alarm(int sig) |
388 | { | |
389 | int save_errno = errno; | |
e424e241 | 390 | |
59c97189 | 391 | signal(SIGALRM, SIG_DFL); |
5260325f | 392 | errno = save_errno; |
59c97189 | 393 | key_do_regen = 1; |
5260325f | 394 | } |
8efc0c15 | 395 | |
396c147e | 396 | static void |
7368a6c8 | 397 | sshd_exchange_identification(int sock_in, int sock_out) |
398 | { | |
2ceb8101 | 399 | u_int i; |
400 | int mismatch; | |
7368a6c8 | 401 | int remote_major, remote_minor; |
a8be9f80 | 402 | int major, minor; |
7368a6c8 | 403 | char *s; |
404 | char buf[256]; /* Must not be larger than remote_version. */ | |
405 | char remote_version[256]; /* Must be at least as big as buf. */ | |
406 | ||
a8be9f80 | 407 | if ((options.protocol & SSH_PROTO_1) && |
408 | (options.protocol & SSH_PROTO_2)) { | |
409 | major = PROTOCOL_MAJOR_1; | |
410 | minor = 99; | |
411 | } else if (options.protocol & SSH_PROTO_2) { | |
412 | major = PROTOCOL_MAJOR_2; | |
413 | minor = PROTOCOL_MINOR_2; | |
414 | } else { | |
415 | major = PROTOCOL_MAJOR_1; | |
416 | minor = PROTOCOL_MINOR_1; | |
417 | } | |
418 | snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", major, minor, SSH_VERSION); | |
7368a6c8 | 419 | server_version_string = xstrdup(buf); |
420 | ||
7b390973 | 421 | /* Send our protocol version identification. */ |
422 | if (atomicio(vwrite, sock_out, server_version_string, | |
423 | strlen(server_version_string)) | |
424 | != strlen(server_version_string)) { | |
425 | logit("Could not write ident string to %s", get_remote_ipaddr()); | |
2362db19 | 426 | cleanup_exit(255); |
7b390973 | 427 | } |
428 | ||
429 | /* Read other sides version identification. */ | |
430 | memset(buf, 0, sizeof(buf)); | |
431 | for (i = 0; i < sizeof(buf) - 1; i++) { | |
432 | if (atomicio(read, sock_in, &buf[i], 1) != 1) { | |
433 | logit("Did not receive identification string from %s", | |
434 | get_remote_ipaddr()); | |
2362db19 | 435 | cleanup_exit(255); |
7368a6c8 | 436 | } |
7b390973 | 437 | if (buf[i] == '\r') { |
438 | buf[i] = 0; | |
439 | /* Kludge for F-Secure Macintosh < 1.0.2 */ | |
440 | if (i == 12 && | |
441 | strncmp(buf, "SSH-1.5-W1.0", 12) == 0) | |
7368a6c8 | 442 | break; |
7b390973 | 443 | continue; |
444 | } | |
445 | if (buf[i] == '\n') { | |
446 | buf[i] = 0; | |
447 | break; | |
7368a6c8 | 448 | } |
7368a6c8 | 449 | } |
7b390973 | 450 | buf[sizeof(buf) - 1] = 0; |
451 | client_version_string = xstrdup(buf); | |
7368a6c8 | 452 | |
453 | /* | |
454 | * Check that the versions match. In future this might accept | |
455 | * several versions and set appropriate flags to handle them. | |
456 | */ | |
457 | if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n", | |
458 | &remote_major, &remote_minor, remote_version) != 3) { | |
6ae2364d | 459 | s = "Protocol mismatch.\n"; |
dc54438a | 460 | (void) atomicio(vwrite, sock_out, s, strlen(s)); |
7368a6c8 | 461 | close(sock_in); |
462 | close(sock_out); | |
bbe88b6d | 463 | logit("Bad protocol version identification '%.100s' from %s", |
7368a6c8 | 464 | client_version_string, get_remote_ipaddr()); |
2362db19 | 465 | cleanup_exit(255); |
7368a6c8 | 466 | } |
467 | debug("Client protocol version %d.%d; client software version %.100s", | |
184eed6a | 468 | remote_major, remote_minor, remote_version); |
7368a6c8 | 469 | |
e78a59f5 | 470 | compat_datafellows(remote_version); |
471 | ||
9a87e2ac | 472 | if (datafellows & SSH_BUG_PROBE) { |
bbe88b6d | 473 | logit("probed from %s with %s. Don't panic.", |
9a87e2ac | 474 | get_remote_ipaddr(), client_version_string); |
2362db19 | 475 | cleanup_exit(255); |
9a87e2ac | 476 | } |
477 | ||
3a1c54d4 | 478 | if (datafellows & SSH_BUG_SCANNER) { |
bbe88b6d | 479 | logit("scanned from %s with %s. Don't panic.", |
3a1c54d4 | 480 | get_remote_ipaddr(), client_version_string); |
2362db19 | 481 | cleanup_exit(255); |
3a1c54d4 | 482 | } |
483 | ||
a8be9f80 | 484 | mismatch = 0; |
6aacefa7 | 485 | switch (remote_major) { |
7368a6c8 | 486 | case 1: |
a306f2dd | 487 | if (remote_minor == 99) { |
488 | if (options.protocol & SSH_PROTO_2) | |
489 | enable_compat20(); | |
490 | else | |
491 | mismatch = 1; | |
492 | break; | |
493 | } | |
a8be9f80 | 494 | if (!(options.protocol & SSH_PROTO_1)) { |
495 | mismatch = 1; | |
496 | break; | |
497 | } | |
7368a6c8 | 498 | if (remote_minor < 3) { |
089fbbd2 | 499 | packet_disconnect("Your ssh version is too old and " |
7368a6c8 | 500 | "is no longer supported. Please install a newer version."); |
501 | } else if (remote_minor == 3) { | |
502 | /* note that this disables agent-forwarding */ | |
503 | enable_compat13(); | |
504 | } | |
a8be9f80 | 505 | break; |
e78a59f5 | 506 | case 2: |
a8be9f80 | 507 | if (options.protocol & SSH_PROTO_2) { |
e78a59f5 | 508 | enable_compat20(); |
509 | break; | |
510 | } | |
511 | /* FALLTHROUGH */ | |
6ae2364d | 512 | default: |
a8be9f80 | 513 | mismatch = 1; |
514 | break; | |
515 | } | |
516 | chop(server_version_string); | |
a8be9f80 | 517 | debug("Local version string %.200s", server_version_string); |
518 | ||
519 | if (mismatch) { | |
7368a6c8 | 520 | s = "Protocol major versions differ.\n"; |
dc54438a | 521 | (void) atomicio(vwrite, sock_out, s, strlen(s)); |
7368a6c8 | 522 | close(sock_in); |
523 | close(sock_out); | |
bbe88b6d | 524 | logit("Protocol major versions differ for %s: %.200s vs. %.200s", |
a8be9f80 | 525 | get_remote_ipaddr(), |
526 | server_version_string, client_version_string); | |
2362db19 | 527 | cleanup_exit(255); |
7368a6c8 | 528 | } |
a306f2dd | 529 | } |
530 | ||
fa08c86b | 531 | /* Destroy the host and server keys. They will no longer be needed. */ |
a306f2dd | 532 | void |
533 | destroy_sensitive_data(void) | |
534 | { | |
fa08c86b | 535 | int i; |
536 | ||
537 | if (sensitive_data.server_key) { | |
538 | key_free(sensitive_data.server_key); | |
539 | sensitive_data.server_key = NULL; | |
540 | } | |
184eed6a | 541 | for (i = 0; i < options.num_host_key_files; i++) { |
fa08c86b | 542 | if (sensitive_data.host_keys[i]) { |
543 | key_free(sensitive_data.host_keys[i]); | |
544 | sensitive_data.host_keys[i] = NULL; | |
545 | } | |
546 | } | |
547 | sensitive_data.ssh1_host_key = NULL; | |
00be5382 | 548 | memset(sensitive_data.ssh1_cookie, 0, SSH_SESSION_KEY_LENGTH); |
fa08c86b | 549 | } |
fa08c86b | 550 | |
1853d1ef | 551 | /* Demote private to public keys for network child */ |
552 | void | |
553 | demote_sensitive_data(void) | |
554 | { | |
555 | Key *tmp; | |
556 | int i; | |
557 | ||
558 | if (sensitive_data.server_key) { | |
559 | tmp = key_demote(sensitive_data.server_key); | |
560 | key_free(sensitive_data.server_key); | |
561 | sensitive_data.server_key = tmp; | |
562 | } | |
563 | ||
564 | for (i = 0; i < options.num_host_key_files; i++) { | |
565 | if (sensitive_data.host_keys[i]) { | |
566 | tmp = key_demote(sensitive_data.host_keys[i]); | |
567 | key_free(sensitive_data.host_keys[i]); | |
568 | sensitive_data.host_keys[i] = tmp; | |
569 | if (tmp->type == KEY_RSA1) | |
570 | sensitive_data.ssh1_host_key = tmp; | |
571 | } | |
572 | } | |
573 | ||
574 | /* We do not clear ssh1_host key and cookie. XXX - Okay Niels? */ | |
575 | } | |
576 | ||
51aeb639 | 577 | static void |
1853d1ef | 578 | privsep_preauth_child(void) |
579 | { | |
7fdc56c5 | 580 | u_int32_t rnd[256]; |
6ded293b | 581 | gid_t gidset[1]; |
2ea6de2b | 582 | struct passwd *pw; |
e424e241 | 583 | int i; |
1853d1ef | 584 | |
585 | /* Enable challenge-response authentication for privilege separation */ | |
586 | privsep_challenge_enable(); | |
587 | ||
588 | for (i = 0; i < 256; i++) | |
7fdc56c5 | 589 | rnd[i] = arc4random(); |
590 | RAND_seed(rnd, sizeof(rnd)); | |
1853d1ef | 591 | |
592 | /* Demote the private keys to public keys. */ | |
593 | demote_sensitive_data(); | |
594 | ||
2ea6de2b | 595 | if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) |
cdc4fc39 | 596 | fatal("Privilege separation user %s does not exist", |
597 | SSH_PRIVSEP_USER); | |
2ea6de2b | 598 | memset(pw->pw_passwd, 0, strlen(pw->pw_passwd)); |
599 | endpwent(); | |
600 | ||
343288b8 | 601 | /* Change our root directory */ |
1c352e97 | 602 | if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1) |
603 | fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR, | |
604 | strerror(errno)); | |
1853d1ef | 605 | if (chdir("/") == -1) |
edfb66cb | 606 | fatal("chdir(\"/\"): %s", strerror(errno)); |
762715ce | 607 | |
1853d1ef | 608 | /* Drop our privileges */ |
2ea6de2b | 609 | debug3("privsep user:group %u:%u", (u_int)pw->pw_uid, |
610 | (u_int)pw->pw_gid); | |
87809a1f | 611 | #if 0 |
6ff58a4b | 612 | /* XXX not ready, too heavy after chroot */ |
2ea6de2b | 613 | do_setusercontext(pw); |
87809a1f | 614 | #else |
615 | gidset[0] = pw->pw_gid; | |
87809a1f | 616 | if (setgroups(1, gidset) < 0) |
617 | fatal("setgroups: %.100s", strerror(errno)); | |
618 | permanently_set_uid(pw); | |
619 | #endif | |
1853d1ef | 620 | } |
621 | ||
2362db19 | 622 | static int |
623 | privsep_preauth(Authctxt *authctxt) | |
1853d1ef | 624 | { |
1853d1ef | 625 | int status; |
324bf712 | 626 | pid_t pid; |
1853d1ef | 627 | |
324bf712 | 628 | /* Set up unprivileged child process to deal with network data */ |
b5a28cbc | 629 | pmonitor = monitor_init(); |
324bf712 | 630 | /* Store a pointer to the kex for later rekeying */ |
b5a28cbc | 631 | pmonitor->m_pkex = &xxx_kex; |
324bf712 | 632 | |
633 | pid = fork(); | |
634 | if (pid == -1) { | |
635 | fatal("fork of unprivileged child failed"); | |
636 | } else if (pid != 0) { | |
c457707e | 637 | debug2("Network child is on pid %ld", (long)pid); |
324bf712 | 638 | |
b5a28cbc | 639 | close(pmonitor->m_recvfd); |
a9b33b95 | 640 | pmonitor->m_pid = pid; |
2362db19 | 641 | monitor_child_preauth(authctxt, pmonitor); |
b5a28cbc | 642 | close(pmonitor->m_sendfd); |
324bf712 | 643 | |
644 | /* Sync memory */ | |
b5a28cbc | 645 | monitor_sync(pmonitor); |
324bf712 | 646 | |
647 | /* Wait for the child's exit status */ | |
8c38e88b | 648 | while (waitpid(pid, &status, 0) < 0) |
649 | if (errno != EINTR) | |
650 | break; | |
2362db19 | 651 | return (1); |
324bf712 | 652 | } else { |
653 | /* child */ | |
654 | ||
b5a28cbc | 655 | close(pmonitor->m_sendfd); |
324bf712 | 656 | |
657 | /* Demote the child */ | |
658 | if (getuid() == 0 || geteuid() == 0) | |
659 | privsep_preauth_child(); | |
47c36e5b | 660 | setproctitle("%s", "[net]"); |
324bf712 | 661 | } |
2362db19 | 662 | return (0); |
324bf712 | 663 | } |
664 | ||
665 | static void | |
666 | privsep_postauth(Authctxt *authctxt) | |
667 | { | |
94d8258b | 668 | #ifdef DISABLE_FD_PASSING |
d170feb1 | 669 | if (1) { |
670 | #else | |
1853d1ef | 671 | if (authctxt->pw->pw_uid == 0 || options.use_login) { |
d170feb1 | 672 | #endif |
1853d1ef | 673 | /* File descriptor passing is broken or root login */ |
1853d1ef | 674 | use_privsep = 0; |
ae25711b | 675 | goto skip; |
1853d1ef | 676 | } |
762715ce | 677 | |
1853d1ef | 678 | /* New socket pair */ |
b5a28cbc | 679 | monitor_reinit(pmonitor); |
1853d1ef | 680 | |
b5a28cbc | 681 | pmonitor->m_pid = fork(); |
682 | if (pmonitor->m_pid == -1) | |
1853d1ef | 683 | fatal("fork of unprivileged child failed"); |
b5a28cbc | 684 | else if (pmonitor->m_pid != 0) { |
c457707e | 685 | debug2("User child is on pid %ld", (long)pmonitor->m_pid); |
b5a28cbc | 686 | close(pmonitor->m_recvfd); |
f143ed33 | 687 | buffer_clear(&loginmsg); |
b5a28cbc | 688 | monitor_child_postauth(pmonitor); |
1853d1ef | 689 | |
690 | /* NEVERREACHED */ | |
691 | exit(0); | |
692 | } | |
693 | ||
b5a28cbc | 694 | close(pmonitor->m_sendfd); |
1853d1ef | 695 | |
696 | /* Demote the private keys to public keys. */ | |
697 | demote_sensitive_data(); | |
698 | ||
699 | /* Drop privileges */ | |
700 | do_setusercontext(authctxt->pw); | |
701 | ||
ae25711b | 702 | skip: |
1853d1ef | 703 | /* It is safe now to apply the key state */ |
b5a28cbc | 704 | monitor_apply_keystate(pmonitor); |
07200973 | 705 | |
706 | /* | |
707 | * Tell the packet layer that authentication was successful, since | |
708 | * this information is not part of the key state. | |
709 | */ | |
710 | packet_set_authenticated(); | |
1853d1ef | 711 | } |
712 | ||
396c147e | 713 | static char * |
fa08c86b | 714 | list_hostkey_types(void) |
715 | { | |
3469eac4 | 716 | Buffer b; |
b6c7b7b7 | 717 | const char *p; |
718 | char *ret; | |
fa08c86b | 719 | int i; |
3469eac4 | 720 | |
721 | buffer_init(&b); | |
184eed6a | 722 | for (i = 0; i < options.num_host_key_files; i++) { |
fa08c86b | 723 | Key *key = sensitive_data.host_keys[i]; |
724 | if (key == NULL) | |
725 | continue; | |
6aacefa7 | 726 | switch (key->type) { |
fa08c86b | 727 | case KEY_RSA: |
728 | case KEY_DSA: | |
3469eac4 | 729 | if (buffer_len(&b) > 0) |
730 | buffer_append(&b, ",", 1); | |
731 | p = key_ssh_name(key); | |
732 | buffer_append(&b, p, strlen(p)); | |
fa08c86b | 733 | break; |
734 | } | |
735 | } | |
3469eac4 | 736 | buffer_append(&b, "\0", 1); |
b6c7b7b7 | 737 | ret = xstrdup(buffer_ptr(&b)); |
3469eac4 | 738 | buffer_free(&b); |
b6c7b7b7 | 739 | debug("list_hostkey_types: %s", ret); |
740 | return ret; | |
fa08c86b | 741 | } |
742 | ||
1853d1ef | 743 | Key * |
fa08c86b | 744 | get_hostkey_by_type(int type) |
745 | { | |
746 | int i; | |
e424e241 | 747 | |
184eed6a | 748 | for (i = 0; i < options.num_host_key_files; i++) { |
fa08c86b | 749 | Key *key = sensitive_data.host_keys[i]; |
750 | if (key != NULL && key->type == type) | |
751 | return key; | |
752 | } | |
753 | return NULL; | |
7368a6c8 | 754 | } |
755 | ||
1853d1ef | 756 | Key * |
757 | get_hostkey_by_index(int ind) | |
758 | { | |
759 | if (ind < 0 || ind >= options.num_host_key_files) | |
760 | return (NULL); | |
761 | return (sensitive_data.host_keys[ind]); | |
762 | } | |
763 | ||
764 | int | |
765 | get_hostkey_index(Key *key) | |
766 | { | |
767 | int i; | |
e424e241 | 768 | |
1853d1ef | 769 | for (i = 0; i < options.num_host_key_files; i++) { |
770 | if (key == sensitive_data.host_keys[i]) | |
771 | return (i); | |
772 | } | |
773 | return (-1); | |
774 | } | |
775 | ||
c345cf9d | 776 | /* |
777 | * returns 1 if connection should be dropped, 0 otherwise. | |
778 | * dropping starts at connection #max_startups_begin with a probability | |
779 | * of (max_startups_rate/100). the probability increases linearly until | |
780 | * all connections are dropped for startups > max_startups | |
781 | */ | |
396c147e | 782 | static int |
c345cf9d | 783 | drop_connection(int startups) |
784 | { | |
1c5eab6f | 785 | int p, r; |
c345cf9d | 786 | |
787 | if (startups < options.max_startups_begin) | |
788 | return 0; | |
789 | if (startups >= options.max_startups) | |
790 | return 1; | |
791 | if (options.max_startups_rate == 100) | |
792 | return 1; | |
793 | ||
794 | p = 100 - options.max_startups_rate; | |
795 | p *= startups - options.max_startups_begin; | |
1c5eab6f | 796 | p /= options.max_startups - options.max_startups_begin; |
c345cf9d | 797 | p += options.max_startups_rate; |
1c5eab6f | 798 | r = arc4random() % 100; |
c345cf9d | 799 | |
e9aec1d4 | 800 | debug("drop_connection: p %d, r %d", p, r); |
c345cf9d | 801 | return (r < p) ? 1 : 0; |
802 | } | |
803 | ||
2717fa0f | 804 | static void |
805 | usage(void) | |
806 | { | |
85ac7a84 | 807 | fprintf(stderr, "%s, %s\n", |
4526e8c2 | 808 | SSH_RELEASE, SSLeay_version(SSLEAY_VERSION)); |
65edde94 | 809 | fprintf(stderr, |
810 | "usage: sshd [-46Ddeiqt] [-b bits] [-f config_file] [-g login_grace_time]\n" | |
811 | " [-h host_key_file] [-k key_gen_time] [-o option] [-p port] [-u len]\n" | |
812 | ); | |
2717fa0f | 813 | exit(1); |
814 | } | |
815 | ||
b9a549d7 | 816 | static void |
817 | send_rexec_state(int fd, Buffer *conf) | |
818 | { | |
819 | Buffer m; | |
820 | ||
821 | debug3("%s: entering fd = %d config len %d", __func__, fd, | |
822 | buffer_len(conf)); | |
823 | ||
824 | /* | |
825 | * Protocol from reexec master to child: | |
826 | * string configuration | |
827 | * u_int ephemeral_key_follows | |
828 | * bignum e (only if ephemeral_key_follows == 1) | |
829 | * bignum n " | |
830 | * bignum d " | |
831 | * bignum iqmp " | |
832 | * bignum p " | |
833 | * bignum q " | |
72f02ae7 | 834 | * string rngseed (only if OpenSSL is not self-seeded) |
b9a549d7 | 835 | */ |
836 | buffer_init(&m); | |
837 | buffer_put_cstring(&m, buffer_ptr(conf)); | |
838 | ||
f2107e97 | 839 | if (sensitive_data.server_key != NULL && |
b9a549d7 | 840 | sensitive_data.server_key->type == KEY_RSA1) { |
841 | buffer_put_int(&m, 1); | |
842 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->e); | |
843 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->n); | |
844 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->d); | |
845 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->iqmp); | |
846 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->p); | |
847 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->q); | |
848 | } else | |
849 | buffer_put_int(&m, 0); | |
850 | ||
72f02ae7 | 851 | #ifndef OPENSSL_PRNG_ONLY |
852 | rexec_send_rng_seed(&m); | |
853 | #endif | |
854 | ||
b9a549d7 | 855 | if (ssh_msg_send(fd, 0, &m) == -1) |
856 | fatal("%s: ssh_msg_send failed", __func__); | |
857 | ||
858 | buffer_free(&m); | |
859 | ||
860 | debug3("%s: done", __func__); | |
861 | } | |
862 | ||
863 | static void | |
864 | recv_rexec_state(int fd, Buffer *conf) | |
865 | { | |
866 | Buffer m; | |
867 | char *cp; | |
868 | u_int len; | |
869 | ||
870 | debug3("%s: entering fd = %d", __func__, fd); | |
871 | ||
872 | buffer_init(&m); | |
873 | ||
874 | if (ssh_msg_recv(fd, &m) == -1) | |
875 | fatal("%s: ssh_msg_recv failed", __func__); | |
876 | if (buffer_get_char(&m) != 0) | |
877 | fatal("%s: rexec version mismatch", __func__); | |
878 | ||
879 | cp = buffer_get_string(&m, &len); | |
880 | if (conf != NULL) | |
881 | buffer_append(conf, cp, len + 1); | |
882 | xfree(cp); | |
883 | ||
884 | if (buffer_get_int(&m)) { | |
885 | if (sensitive_data.server_key != NULL) | |
886 | key_free(sensitive_data.server_key); | |
887 | sensitive_data.server_key = key_new_private(KEY_RSA1); | |
888 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->e); | |
889 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->n); | |
890 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->d); | |
891 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->iqmp); | |
892 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->p); | |
893 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->q); | |
894 | rsa_generate_additional_parameters( | |
895 | sensitive_data.server_key->rsa); | |
896 | } | |
72f02ae7 | 897 | |
898 | #ifndef OPENSSL_PRNG_ONLY | |
899 | rexec_recv_rng_seed(&m); | |
900 | #endif | |
901 | ||
b9a549d7 | 902 | buffer_free(&m); |
903 | ||
904 | debug3("%s: done", __func__); | |
905 | } | |
906 | ||
e07335e2 | 907 | /* Accept a connection from inetd */ |
908 | static void | |
909 | server_accept_inetd(int *sock_in, int *sock_out) | |
910 | { | |
911 | int fd; | |
912 | ||
913 | startup_pipe = -1; | |
914 | if (rexeced_flag) { | |
915 | close(REEXEC_CONFIG_PASS_FD); | |
916 | *sock_in = *sock_out = dup(STDIN_FILENO); | |
917 | if (!debug_flag) { | |
918 | startup_pipe = dup(REEXEC_STARTUP_PIPE_FD); | |
919 | close(REEXEC_STARTUP_PIPE_FD); | |
920 | } | |
921 | } else { | |
922 | *sock_in = dup(STDIN_FILENO); | |
923 | *sock_out = dup(STDOUT_FILENO); | |
924 | } | |
925 | /* | |
926 | * We intentionally do not close the descriptors 0, 1, and 2 | |
927 | * as our code for setting the descriptors won't work if | |
928 | * ttyfd happens to be one of those. | |
929 | */ | |
930 | if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { | |
931 | dup2(fd, STDIN_FILENO); | |
932 | dup2(fd, STDOUT_FILENO); | |
933 | if (fd > STDOUT_FILENO) | |
934 | close(fd); | |
935 | } | |
936 | debug("inetd sockets after dupping: %d, %d", *sock_in, *sock_out); | |
937 | } | |
938 | ||
939 | /* | |
940 | * Listen for TCP connections | |
941 | */ | |
942 | static void | |
943 | server_listen(void) | |
944 | { | |
945 | int ret, listen_sock, on = 1; | |
946 | struct addrinfo *ai; | |
947 | char ntop[NI_MAXHOST], strport[NI_MAXSERV]; | |
948 | ||
949 | for (ai = options.listen_addrs; ai; ai = ai->ai_next) { | |
950 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) | |
951 | continue; | |
952 | if (num_listen_socks >= MAX_LISTEN_SOCKS) | |
953 | fatal("Too many listen sockets. " | |
954 | "Enlarge MAX_LISTEN_SOCKS"); | |
955 | if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen, | |
956 | ntop, sizeof(ntop), strport, sizeof(strport), | |
957 | NI_NUMERICHOST|NI_NUMERICSERV)) != 0) { | |
958 | error("getnameinfo failed: %.100s", | |
959 | (ret != EAI_SYSTEM) ? gai_strerror(ret) : | |
960 | strerror(errno)); | |
961 | continue; | |
962 | } | |
963 | /* Create socket for listening. */ | |
964 | listen_sock = socket(ai->ai_family, ai->ai_socktype, | |
965 | ai->ai_protocol); | |
966 | if (listen_sock < 0) { | |
967 | /* kernel may not support ipv6 */ | |
968 | verbose("socket: %.100s", strerror(errno)); | |
969 | continue; | |
970 | } | |
971 | if (set_nonblock(listen_sock) == -1) { | |
972 | close(listen_sock); | |
973 | continue; | |
974 | } | |
975 | /* | |
976 | * Set socket options. | |
977 | * Allow local port reuse in TIME_WAIT. | |
978 | */ | |
979 | if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR, | |
980 | &on, sizeof(on)) == -1) | |
981 | error("setsockopt SO_REUSEADDR: %s", strerror(errno)); | |
982 | ||
983 | debug("Bind to port %s on %s.", strport, ntop); | |
984 | ||
985 | /* Bind the socket to the desired port. */ | |
986 | if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) { | |
987 | error("Bind to port %s on %s failed: %.200s.", | |
988 | strport, ntop, strerror(errno)); | |
989 | close(listen_sock); | |
990 | continue; | |
991 | } | |
992 | listen_socks[num_listen_socks] = listen_sock; | |
993 | num_listen_socks++; | |
994 | ||
995 | /* Start listening on the port. */ | |
996 | if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0) | |
997 | fatal("listen on [%s]:%s: %.100s", | |
998 | ntop, strport, strerror(errno)); | |
999 | logit("Server listening on %s port %s.", ntop, strport); | |
1000 | } | |
1001 | freeaddrinfo(options.listen_addrs); | |
1002 | ||
1003 | if (!num_listen_socks) | |
1004 | fatal("Cannot bind any address."); | |
1005 | } | |
1006 | ||
1007 | /* | |
1008 | * The main TCP accept loop. Note that, for the non-debug case, returns | |
1009 | * from this function are in a forked subprocess. | |
1010 | */ | |
1011 | static void | |
1012 | server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s) | |
1013 | { | |
1014 | fd_set *fdset; | |
1015 | int i, j, ret, maxfd; | |
1016 | int key_used = 0, startups = 0; | |
1017 | int startup_p[2] = { -1 , -1 }; | |
1018 | struct sockaddr_storage from; | |
1019 | socklen_t fromlen; | |
1020 | pid_t pid; | |
1021 | ||
1022 | /* setup fd set for accept */ | |
1023 | fdset = NULL; | |
1024 | maxfd = 0; | |
1025 | for (i = 0; i < num_listen_socks; i++) | |
1026 | if (listen_socks[i] > maxfd) | |
1027 | maxfd = listen_socks[i]; | |
1028 | /* pipes connected to unauthenticated childs */ | |
1029 | startup_pipes = xcalloc(options.max_startups, sizeof(int)); | |
1030 | for (i = 0; i < options.max_startups; i++) | |
1031 | startup_pipes[i] = -1; | |
1032 | ||
1033 | /* | |
1034 | * Stay listening for connections until the system crashes or | |
1035 | * the daemon is killed with a signal. | |
1036 | */ | |
1037 | for (;;) { | |
1038 | if (received_sighup) | |
1039 | sighup_restart(); | |
1040 | if (fdset != NULL) | |
1041 | xfree(fdset); | |
1042 | fdset = (fd_set *)xcalloc(howmany(maxfd + 1, NFDBITS), | |
1043 | sizeof(fd_mask)); | |
1044 | ||
1045 | for (i = 0; i < num_listen_socks; i++) | |
1046 | FD_SET(listen_socks[i], fdset); | |
1047 | for (i = 0; i < options.max_startups; i++) | |
1048 | if (startup_pipes[i] != -1) | |
1049 | FD_SET(startup_pipes[i], fdset); | |
1050 | ||
1051 | /* Wait in select until there is a connection. */ | |
1052 | ret = select(maxfd+1, fdset, NULL, NULL, NULL); | |
1053 | if (ret < 0 && errno != EINTR) | |
1054 | error("select: %.100s", strerror(errno)); | |
1055 | if (received_sigterm) { | |
1056 | logit("Received signal %d; terminating.", | |
1057 | (int) received_sigterm); | |
1058 | close_listen_socks(); | |
1059 | unlink(options.pid_file); | |
1060 | exit(255); | |
1061 | } | |
1062 | if (key_used && key_do_regen) { | |
1063 | generate_ephemeral_server_key(); | |
1064 | key_used = 0; | |
1065 | key_do_regen = 0; | |
1066 | } | |
1067 | if (ret < 0) | |
1068 | continue; | |
1069 | ||
1070 | for (i = 0; i < options.max_startups; i++) | |
1071 | if (startup_pipes[i] != -1 && | |
1072 | FD_ISSET(startup_pipes[i], fdset)) { | |
1073 | /* | |
1074 | * the read end of the pipe is ready | |
1075 | * if the child has closed the pipe | |
1076 | * after successful authentication | |
1077 | * or if the child has died | |
1078 | */ | |
1079 | close(startup_pipes[i]); | |
1080 | startup_pipes[i] = -1; | |
1081 | startups--; | |
1082 | } | |
1083 | for (i = 0; i < num_listen_socks; i++) { | |
1084 | if (!FD_ISSET(listen_socks[i], fdset)) | |
1085 | continue; | |
1086 | fromlen = sizeof(from); | |
1087 | *newsock = accept(listen_socks[i], | |
1088 | (struct sockaddr *)&from, &fromlen); | |
1089 | if (*newsock < 0) { | |
1090 | if (errno != EINTR && errno != EWOULDBLOCK) | |
1091 | error("accept: %.100s", strerror(errno)); | |
1092 | continue; | |
1093 | } | |
1094 | if (unset_nonblock(*newsock) == -1) { | |
1095 | close(*newsock); | |
1096 | continue; | |
1097 | } | |
1098 | if (drop_connection(startups) == 1) { | |
1099 | debug("drop connection #%d", startups); | |
1100 | close(*newsock); | |
1101 | continue; | |
1102 | } | |
1103 | if (pipe(startup_p) == -1) { | |
1104 | close(*newsock); | |
1105 | continue; | |
1106 | } | |
1107 | ||
1108 | if (rexec_flag && socketpair(AF_UNIX, | |
1109 | SOCK_STREAM, 0, config_s) == -1) { | |
1110 | error("reexec socketpair: %s", | |
1111 | strerror(errno)); | |
1112 | close(*newsock); | |
1113 | close(startup_p[0]); | |
1114 | close(startup_p[1]); | |
1115 | continue; | |
1116 | } | |
1117 | ||
1118 | for (j = 0; j < options.max_startups; j++) | |
1119 | if (startup_pipes[j] == -1) { | |
1120 | startup_pipes[j] = startup_p[0]; | |
1121 | if (maxfd < startup_p[0]) | |
1122 | maxfd = startup_p[0]; | |
1123 | startups++; | |
1124 | break; | |
1125 | } | |
1126 | ||
1127 | /* | |
1128 | * Got connection. Fork a child to handle it, unless | |
1129 | * we are in debugging mode. | |
1130 | */ | |
1131 | if (debug_flag) { | |
1132 | /* | |
1133 | * In debugging mode. Close the listening | |
1134 | * socket, and start processing the | |
1135 | * connection without forking. | |
1136 | */ | |
1137 | debug("Server will not fork when running in debugging mode."); | |
1138 | close_listen_socks(); | |
1139 | *sock_in = *newsock; | |
1140 | *sock_out = *newsock; | |
1141 | close(startup_p[0]); | |
1142 | close(startup_p[1]); | |
1143 | startup_pipe = -1; | |
1144 | pid = getpid(); | |
1145 | if (rexec_flag) { | |
1146 | send_rexec_state(config_s[0], | |
1147 | &cfg); | |
1148 | close(config_s[0]); | |
1149 | } | |
1150 | break; | |
1151 | } | |
1152 | ||
1153 | /* | |
1154 | * Normal production daemon. Fork, and have | |
1155 | * the child process the connection. The | |
1156 | * parent continues listening. | |
1157 | */ | |
5b84789f | 1158 | platform_pre_fork(); |
e07335e2 | 1159 | if ((pid = fork()) == 0) { |
1160 | /* | |
1161 | * Child. Close the listening and | |
1162 | * max_startup sockets. Start using | |
1163 | * the accepted socket. Reinitialize | |
1164 | * logging (since our pid has changed). | |
1165 | * We break out of the loop to handle | |
1166 | * the connection. | |
1167 | */ | |
5b84789f | 1168 | platform_post_fork_child(); |
e07335e2 | 1169 | startup_pipe = startup_p[1]; |
1170 | close_startup_pipes(); | |
1171 | close_listen_socks(); | |
1172 | *sock_in = *newsock; | |
1173 | *sock_out = *newsock; | |
1174 | log_init(__progname, | |
1175 | options.log_level, | |
1176 | options.log_facility, | |
1177 | log_stderr); | |
1178 | if (rexec_flag) | |
1179 | close(config_s[0]); | |
1180 | break; | |
1181 | } | |
1182 | ||
1183 | /* Parent. Stay in the loop. */ | |
5b84789f | 1184 | platform_post_fork_parent(pid); |
e07335e2 | 1185 | if (pid < 0) |
1186 | error("fork: %.100s", strerror(errno)); | |
1187 | else | |
1188 | debug("Forked child %ld.", (long)pid); | |
1189 | ||
1190 | close(startup_p[1]); | |
1191 | ||
1192 | if (rexec_flag) { | |
1193 | send_rexec_state(config_s[0], &cfg); | |
1194 | close(config_s[0]); | |
1195 | close(config_s[1]); | |
1196 | } | |
1197 | ||
1198 | /* | |
1199 | * Mark that the key has been used (it | |
1200 | * was "given" to the child). | |
1201 | */ | |
1202 | if ((options.protocol & SSH_PROTO_1) && | |
1203 | key_used == 0) { | |
1204 | /* Schedule server key regeneration alarm. */ | |
1205 | signal(SIGALRM, key_regeneration_alarm); | |
1206 | alarm(options.key_regeneration_time); | |
1207 | key_used = 1; | |
1208 | } | |
1209 | ||
1210 | close(*newsock); | |
1211 | ||
1212 | /* | |
1213 | * Ensure that our random state differs | |
1214 | * from that of the child | |
1215 | */ | |
1216 | arc4random_stir(); | |
1217 | } | |
1218 | ||
1219 | /* child process check (or debug mode) */ | |
1220 | if (num_listen_socks < 0) | |
1221 | break; | |
1222 | } | |
1223 | } | |
1224 | ||
1225 | ||
5260325f | 1226 | /* |
1227 | * Main program for the daemon. | |
1228 | */ | |
8efc0c15 | 1229 | int |
1230 | main(int ac, char **av) | |
1231 | { | |
5260325f | 1232 | extern char *optarg; |
1233 | extern int optind; | |
e07335e2 | 1234 | int opt, i, on = 1; |
83529a6b | 1235 | int sock_in = -1, sock_out = -1, newsock = -1; |
5260325f | 1236 | const char *remote_ip; |
1237 | int remote_port; | |
c5894280 | 1238 | char *line; |
e07335e2 | 1239 | int config_s[2] = { -1 , -1 }; |
aeaa3d9e | 1240 | Key *key; |
2362db19 | 1241 | Authctxt *authctxt; |
5260325f | 1242 | |
6e879cb4 | 1243 | #ifdef HAVE_SECUREWARE |
1244 | (void)set_auth_parameters(ac, av); | |
1245 | #endif | |
fda04d7d | 1246 | __progname = ssh_get_progname(av[0]); |
264dce47 | 1247 | init_rng(); |
1248 | ||
d0104542 | 1249 | /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */ |
4d33e531 | 1250 | saved_argc = ac; |
7706b4c7 | 1251 | rexec_argc = ac; |
01d35895 | 1252 | saved_argv = xcalloc(ac + 1, sizeof(*saved_argv)); |
d0104542 | 1253 | for (i = 0; i < ac; i++) |
1254 | saved_argv[i] = xstrdup(av[i]); | |
f420d2ba | 1255 | saved_argv[i] = NULL; |
d0104542 | 1256 | |
1257 | #ifndef HAVE_SETPROCTITLE | |
1258 | /* Prepare for later setproctitle emulation */ | |
1259 | compat_init_setproctitle(ac, av); | |
416c732d | 1260 | av = saved_argv; |
d0104542 | 1261 | #endif |
5260325f | 1262 | |
a4c0faa2 | 1263 | if (geteuid() == 0 && setgroups(0, NULL) == -1) |
1264 | debug("setgroups(): %.200s", strerror(errno)); | |
1265 | ||
fd6168c1 | 1266 | /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ |
1267 | sanitise_stdfd(); | |
1268 | ||
5260325f | 1269 | /* Initialize configuration options to their default values. */ |
1270 | initialize_server_options(&options); | |
1271 | ||
1272 | /* Parse command-line arguments. */ | |
b9a549d7 | 1273 | while ((opt = getopt(ac, av, "f:p:b:k:h:g:u:o:dDeiqrtQR46")) != -1) { |
5260325f | 1274 | switch (opt) { |
48e671d5 | 1275 | case '4': |
31b41ceb | 1276 | options.address_family = AF_INET; |
48e671d5 | 1277 | break; |
1278 | case '6': | |
31b41ceb | 1279 | options.address_family = AF_INET6; |
48e671d5 | 1280 | break; |
5260325f | 1281 | case 'f': |
1282 | config_file_name = optarg; | |
1283 | break; | |
1284 | case 'd': | |
e053cd2c | 1285 | if (debug_flag == 0) { |
bcbf86ec | 1286 | debug_flag = 1; |
1287 | options.log_level = SYSLOG_LEVEL_DEBUG1; | |
e053cd2c | 1288 | } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) |
bcbf86ec | 1289 | options.log_level++; |
5260325f | 1290 | break; |
0b6fbf03 | 1291 | case 'D': |
1292 | no_daemon_flag = 1; | |
1293 | break; | |
ff14faf1 | 1294 | case 'e': |
1295 | log_stderr = 1; | |
1296 | break; | |
5260325f | 1297 | case 'i': |
1298 | inetd_flag = 1; | |
1299 | break; | |
b9a549d7 | 1300 | case 'r': |
1301 | rexec_flag = 0; | |
1302 | break; | |
1303 | case 'R': | |
1304 | rexeced_flag = 1; | |
1305 | inetd_flag = 1; | |
1306 | break; | |
5260325f | 1307 | case 'Q': |
9bd5b720 | 1308 | /* ignored */ |
5260325f | 1309 | break; |
1310 | case 'q': | |
1311 | options.log_level = SYSLOG_LEVEL_QUIET; | |
1312 | break; | |
1313 | case 'b': | |
3efa8ea9 | 1314 | options.server_key_bits = (int)strtonum(optarg, 256, |
1315 | 32768, NULL); | |
5260325f | 1316 | break; |
1317 | case 'p': | |
48e671d5 | 1318 | options.ports_from_cmdline = 1; |
bcbf86ec | 1319 | if (options.num_ports >= MAX_PORTS) { |
1320 | fprintf(stderr, "too many ports.\n"); | |
1321 | exit(1); | |
1322 | } | |
2d2a2c65 | 1323 | options.ports[options.num_ports++] = a2port(optarg); |
1324 | if (options.ports[options.num_ports-1] == 0) { | |
1325 | fprintf(stderr, "Bad port number.\n"); | |
1326 | exit(1); | |
1327 | } | |
5260325f | 1328 | break; |
1329 | case 'g': | |
e2b1fb42 | 1330 | if ((options.login_grace_time = convtime(optarg)) == -1) { |
1331 | fprintf(stderr, "Invalid login grace time.\n"); | |
1332 | exit(1); | |
1333 | } | |
5260325f | 1334 | break; |
1335 | case 'k': | |
e2b1fb42 | 1336 | if ((options.key_regeneration_time = convtime(optarg)) == -1) { |
1337 | fprintf(stderr, "Invalid key regeneration interval.\n"); | |
1338 | exit(1); | |
1339 | } | |
5260325f | 1340 | break; |
1341 | case 'h': | |
fa08c86b | 1342 | if (options.num_host_key_files >= MAX_HOSTKEYS) { |
1343 | fprintf(stderr, "too many host keys.\n"); | |
1344 | exit(1); | |
1345 | } | |
1346 | options.host_key_files[options.num_host_key_files++] = optarg; | |
5260325f | 1347 | break; |
f87f09aa | 1348 | case 't': |
1349 | test_flag = 1; | |
1350 | break; | |
c345cf9d | 1351 | case 'u': |
3efa8ea9 | 1352 | utmp_len = (u_int)strtonum(optarg, 0, MAXHOSTNAMELEN+1, NULL); |
67f04db1 | 1353 | if (utmp_len > MAXHOSTNAMELEN) { |
1354 | fprintf(stderr, "Invalid utmp length.\n"); | |
1355 | exit(1); | |
1356 | } | |
c345cf9d | 1357 | break; |
2717fa0f | 1358 | case 'o': |
c5894280 | 1359 | line = xstrdup(optarg); |
1360 | if (process_server_config_line(&options, line, | |
d231781a | 1361 | "command-line", 0, NULL, NULL, NULL, NULL) != 0) |
184eed6a | 1362 | exit(1); |
c5894280 | 1363 | xfree(line); |
2717fa0f | 1364 | break; |
5260325f | 1365 | case '?': |
1366 | default: | |
2717fa0f | 1367 | usage(); |
1368 | break; | |
5260325f | 1369 | } |
1370 | } | |
b9a549d7 | 1371 | if (rexeced_flag || inetd_flag) |
1372 | rexec_flag = 0; | |
1373 | if (rexec_flag && (av[0] == NULL || *av[0] != '/')) | |
1374 | fatal("sshd re-exec requires execution with an absolute path"); | |
1375 | if (rexeced_flag) | |
b250e837 | 1376 | closefrom(REEXEC_MIN_FREE_FD); |
1377 | else | |
1378 | closefrom(REEXEC_DEVCRYPTO_RESERVED_FD); | |
b9a549d7 | 1379 | |
1a92bd7e | 1380 | SSLeay_add_all_algorithms(); |
5260325f | 1381 | |
48e671d5 | 1382 | /* |
1383 | * Force logging to stderr until we have loaded the private host | |
1384 | * key (unless started from inetd) | |
1385 | */ | |
1fe6a48f | 1386 | log_init(__progname, |
980c9344 | 1387 | options.log_level == SYSLOG_LEVEL_NOT_SET ? |
1388 | SYSLOG_LEVEL_INFO : options.log_level, | |
1389 | options.log_facility == SYSLOG_FACILITY_NOT_SET ? | |
1390 | SYSLOG_FACILITY_AUTH : options.log_facility, | |
51efad8c | 1391 | log_stderr || !inetd_flag); |
48e671d5 | 1392 | |
351f44a0 | 1393 | /* |
1394 | * Unset KRB5CCNAME, otherwise the user's session may inherit it from | |
1395 | * root's environment | |
d1cf9a87 | 1396 | */ |
3bfd27d5 | 1397 | if (getenv("KRB5CCNAME") != NULL) |
1398 | unsetenv("KRB5CCNAME"); | |
1399 | ||
ef51930f | 1400 | #ifdef _UNICOS |
e5ba4718 | 1401 | /* Cray can define user privs drop all privs now! |
1a23ac2c | 1402 | * Not needed on PRIV_SU systems! |
1403 | */ | |
1404 | drop_cray_privs(); | |
1405 | #endif | |
1406 | ||
b9a549d7 | 1407 | sensitive_data.server_key = NULL; |
1408 | sensitive_data.ssh1_host_key = NULL; | |
1409 | sensitive_data.have_ssh1_key = 0; | |
1410 | sensitive_data.have_ssh2_key = 0; | |
1411 | ||
1412 | /* Fetch our configuration */ | |
1413 | buffer_init(&cfg); | |
1414 | if (rexeced_flag) | |
b250e837 | 1415 | recv_rexec_state(REEXEC_CONFIG_PASS_FD, &cfg); |
b9a549d7 | 1416 | else |
1417 | load_server_config(config_file_name, &cfg); | |
1418 | ||
d231781a | 1419 | parse_server_config(&options, rexeced_flag ? "rexec" : config_file_name, |
1420 | &cfg, NULL, NULL, NULL); | |
5260325f | 1421 | |
72f02ae7 | 1422 | seed_rng(); |
1423 | ||
5260325f | 1424 | /* Fill in default values for those options not explicitly set. */ |
1425 | fill_default_server_options(&options); | |
1426 | ||
31b41ceb | 1427 | /* set default channel AF */ |
1428 | channel_set_af(options.address_family); | |
1429 | ||
5260325f | 1430 | /* Check that there are no remaining arguments. */ |
1431 | if (optind < ac) { | |
1432 | fprintf(stderr, "Extra argument %s.\n", av[optind]); | |
1433 | exit(1); | |
8efc0c15 | 1434 | } |
5260325f | 1435 | |
4526e8c2 | 1436 | debug("sshd version %.100s", SSH_RELEASE); |
5260325f | 1437 | |
fa08c86b | 1438 | /* load private host keys */ |
52e3daed | 1439 | sensitive_data.host_keys = xcalloc(options.num_host_key_files, |
343288b8 | 1440 | sizeof(Key *)); |
184eed6a | 1441 | for (i = 0; i < options.num_host_key_files; i++) |
1e3b8b07 | 1442 | sensitive_data.host_keys[i] = NULL; |
a306f2dd | 1443 | |
184eed6a | 1444 | for (i = 0; i < options.num_host_key_files; i++) { |
aeaa3d9e | 1445 | key = key_load_private(options.host_key_files[i], "", NULL); |
1446 | sensitive_data.host_keys[i] = key; | |
fa08c86b | 1447 | if (key == NULL) { |
58cfa257 | 1448 | error("Could not load host key: %s", |
1449 | options.host_key_files[i]); | |
aeaa3d9e | 1450 | sensitive_data.host_keys[i] = NULL; |
fa08c86b | 1451 | continue; |
a306f2dd | 1452 | } |
6aacefa7 | 1453 | switch (key->type) { |
fa08c86b | 1454 | case KEY_RSA1: |
1455 | sensitive_data.ssh1_host_key = key; | |
1456 | sensitive_data.have_ssh1_key = 1; | |
1457 | break; | |
1458 | case KEY_RSA: | |
1459 | case KEY_DSA: | |
1460 | sensitive_data.have_ssh2_key = 1; | |
1461 | break; | |
a306f2dd | 1462 | } |
aeaa3d9e | 1463 | debug("private host key: #%d type %d %s", i, key->type, |
1464 | key_type(key)); | |
fa08c86b | 1465 | } |
1466 | if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) { | |
bbe88b6d | 1467 | logit("Disabling protocol version 1. Could not load host key"); |
fa08c86b | 1468 | options.protocol &= ~SSH_PROTO_1; |
1469 | } | |
1470 | if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) { | |
bbe88b6d | 1471 | logit("Disabling protocol version 2. Could not load host key"); |
fa08c86b | 1472 | options.protocol &= ~SSH_PROTO_2; |
a306f2dd | 1473 | } |
6a416424 | 1474 | if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) { |
bbe88b6d | 1475 | logit("sshd: no hostkeys available -- exiting."); |
5260325f | 1476 | exit(1); |
1477 | } | |
5260325f | 1478 | |
a306f2dd | 1479 | /* Check certain values for sanity. */ |
1480 | if (options.protocol & SSH_PROTO_1) { | |
1481 | if (options.server_key_bits < 512 || | |
1482 | options.server_key_bits > 32768) { | |
1483 | fprintf(stderr, "Bad server key size.\n"); | |
1484 | exit(1); | |
1485 | } | |
1486 | /* | |
1487 | * Check that server and host key lengths differ sufficiently. This | |
1488 | * is necessary to make double encryption work with rsaref. Oh, I | |
1489 | * hate software patents. I dont know if this can go? Niels | |
1490 | */ | |
1491 | if (options.server_key_bits > | |
e424e241 | 1492 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) - |
1493 | SSH_KEY_BITS_RESERVED && options.server_key_bits < | |
1494 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + | |
1495 | SSH_KEY_BITS_RESERVED) { | |
a306f2dd | 1496 | options.server_key_bits = |
e424e241 | 1497 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + |
1498 | SSH_KEY_BITS_RESERVED; | |
a306f2dd | 1499 | debug("Forcing server key to %d bits to make it differ from host key.", |
1500 | options.server_key_bits); | |
1501 | } | |
1502 | } | |
1503 | ||
3cc54fbb | 1504 | if (use_privsep) { |
3cc54fbb | 1505 | struct stat st; |
1506 | ||
3efa8ea9 | 1507 | if (getpwnam(SSH_PRIVSEP_USER) == NULL) |
3cc54fbb | 1508 | fatal("Privilege separation user %s does not exist", |
1509 | SSH_PRIVSEP_USER); | |
1510 | if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) || | |
1511 | (S_ISDIR(st.st_mode) == 0)) | |
1512 | fatal("Missing privilege separation directory: %s", | |
1513 | _PATH_PRIVSEP_CHROOT_DIR); | |
b9b82dab | 1514 | |
1515 | #ifdef HAVE_CYGWIN | |
1516 | if (check_ntsec(_PATH_PRIVSEP_CHROOT_DIR) && | |
1517 | (st.st_uid != getuid () || | |
1518 | (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)) | |
1519 | #else | |
a56313d7 | 1520 | if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0) |
b9b82dab | 1521 | #endif |
5f021474 | 1522 | fatal("%s must be owned by root and not group or " |
1523 | "world-writable.", _PATH_PRIVSEP_CHROOT_DIR); | |
3cc54fbb | 1524 | } |
1525 | ||
f87f09aa | 1526 | /* Configuration looks good, so exit if in test mode. */ |
1527 | if (test_flag) | |
1528 | exit(0); | |
1529 | ||
018a5ea3 | 1530 | /* |
1531 | * Clear out any supplemental groups we may have inherited. This | |
1532 | * prevents inadvertent creation of files with bad modes (in the | |
aff51935 | 1533 | * portable version at least, it's certainly possible for PAM |
1534 | * to create a file, and we can't control the code in every | |
018a5ea3 | 1535 | * module which might be used). |
1536 | */ | |
1537 | if (setgroups(0, NULL) < 0) | |
1538 | debug("setgroups() failed: %.200s", strerror(errno)); | |
1539 | ||
b9a549d7 | 1540 | if (rexec_flag) { |
52e3daed | 1541 | rexec_argv = xcalloc(rexec_argc + 2, sizeof(char *)); |
b9a549d7 | 1542 | for (i = 0; i < rexec_argc; i++) { |
1543 | debug("rexec_argv[%d]='%s'", i, saved_argv[i]); | |
1544 | rexec_argv[i] = saved_argv[i]; | |
1545 | } | |
1546 | rexec_argv[rexec_argc] = "-R"; | |
1547 | rexec_argv[rexec_argc + 1] = NULL; | |
1548 | } | |
1549 | ||
a306f2dd | 1550 | /* Initialize the log (it is reinitialized below in case we forked). */ |
25c31d49 | 1551 | if (debug_flag && (!inetd_flag || rexeced_flag)) |
5260325f | 1552 | log_stderr = 1; |
1fe6a48f | 1553 | log_init(__progname, options.log_level, options.log_facility, log_stderr); |
5260325f | 1554 | |
a306f2dd | 1555 | /* |
1556 | * If not in debugging mode, and not started from inetd, disconnect | |
1557 | * from the controlling terminal, and fork. The original process | |
1558 | * exits. | |
1559 | */ | |
0b6fbf03 | 1560 | if (!(debug_flag || inetd_flag || no_daemon_flag)) { |
8efc0c15 | 1561 | #ifdef TIOCNOTTY |
5260325f | 1562 | int fd; |
8efc0c15 | 1563 | #endif /* TIOCNOTTY */ |
5260325f | 1564 | if (daemon(0, 0) < 0) |
1565 | fatal("daemon() failed: %.200s", strerror(errno)); | |
1566 | ||
1567 | /* Disconnect from the controlling tty. */ | |
8efc0c15 | 1568 | #ifdef TIOCNOTTY |
5ca51e19 | 1569 | fd = open(_PATH_TTY, O_RDWR | O_NOCTTY); |
5260325f | 1570 | if (fd >= 0) { |
1571 | (void) ioctl(fd, TIOCNOTTY, NULL); | |
1572 | close(fd); | |
1573 | } | |
8efc0c15 | 1574 | #endif /* TIOCNOTTY */ |
8efc0c15 | 1575 | } |
5260325f | 1576 | /* Reinitialize the log (because of the fork above). */ |
1fe6a48f | 1577 | log_init(__progname, options.log_level, options.log_facility, log_stderr); |
5260325f | 1578 | |
5260325f | 1579 | /* Initialize the random number generator. */ |
1580 | arc4random_stir(); | |
1581 | ||
1582 | /* Chdir to the root directory so that the current disk can be | |
1583 | unmounted if desired. */ | |
1584 | chdir("/"); | |
184eed6a | 1585 | |
1d3c30db | 1586 | /* ignore SIGPIPE */ |
1587 | signal(SIGPIPE, SIG_IGN); | |
5260325f | 1588 | |
e07335e2 | 1589 | /* Get a connection, either from inetd or a listening TCP socket */ |
5260325f | 1590 | if (inetd_flag) { |
e07335e2 | 1591 | server_accept_inetd(&sock_in, &sock_out); |
b9a549d7 | 1592 | |
b9a549d7 | 1593 | if ((options.protocol & SSH_PROTO_1) && |
1594 | sensitive_data.server_key == NULL) | |
cb7bd922 | 1595 | generate_ephemeral_server_key(); |
5260325f | 1596 | } else { |
e07335e2 | 1597 | server_listen(); |
48e671d5 | 1598 | |
3aca00a3 | 1599 | if (options.protocol & SSH_PROTO_1) |
1600 | generate_ephemeral_server_key(); | |
1601 | ||
3aca00a3 | 1602 | signal(SIGHUP, sighup_handler); |
e07335e2 | 1603 | signal(SIGCHLD, main_sigchld_handler); |
3aca00a3 | 1604 | signal(SIGTERM, sigterm_handler); |
1605 | signal(SIGQUIT, sigterm_handler); | |
1606 | ||
e07335e2 | 1607 | /* |
1608 | * Write out the pid file after the sigterm handler | |
1609 | * is setup and the listen sockets are bound | |
1610 | */ | |
5260325f | 1611 | if (!debug_flag) { |
e07335e2 | 1612 | FILE *f = fopen(options.pid_file, "w"); |
1613 | ||
71b9ced0 | 1614 | if (f == NULL) { |
1615 | error("Couldn't create pid file \"%s\": %s", | |
1616 | options.pid_file, strerror(errno)); | |
1617 | } else { | |
c457707e | 1618 | fprintf(f, "%ld\n", (long) getpid()); |
5260325f | 1619 | fclose(f); |
1620 | } | |
8efc0c15 | 1621 | } |
5260325f | 1622 | |
e07335e2 | 1623 | /* Accept a connection and return in a forked child */ |
1624 | server_accept_loop(&sock_in, &sock_out, | |
1625 | &newsock, config_s); | |
5260325f | 1626 | } |
8efc0c15 | 1627 | |
5260325f | 1628 | /* This is the child processing a new connection. */ |
cc120685 | 1629 | setproctitle("%s", "[accepted]"); |
5260325f | 1630 | |
8b758bd2 | 1631 | /* |
1632 | * Create a new session and process group since the 4.4BSD | |
1633 | * setlogin() affects the entire process group. We don't | |
1634 | * want the child to be able to affect the parent. | |
1635 | */ | |
1636 | #if !defined(SSHD_ACQUIRES_CTTY) | |
1637 | /* | |
1638 | * If setsid is called, on some platforms sshd will later acquire a | |
1639 | * controlling terminal which will result in "could not set | |
1640 | * controlling tty" errors. | |
1641 | */ | |
1642 | if (!debug_flag && !inetd_flag && setsid() < 0) | |
1643 | error("setsid: %.100s", strerror(errno)); | |
1644 | #endif | |
1645 | ||
b9a549d7 | 1646 | if (rexec_flag) { |
1647 | int fd; | |
1648 | ||
b250e837 | 1649 | debug("rexec start in %d out %d newsock %d pipe %d sock %d", |
1650 | sock_in, sock_out, newsock, startup_pipe, config_s[0]); | |
b9a549d7 | 1651 | dup2(newsock, STDIN_FILENO); |
1652 | dup2(STDIN_FILENO, STDOUT_FILENO); | |
1653 | if (startup_pipe == -1) | |
b250e837 | 1654 | close(REEXEC_STARTUP_PIPE_FD); |
b9a549d7 | 1655 | else |
b250e837 | 1656 | dup2(startup_pipe, REEXEC_STARTUP_PIPE_FD); |
b9a549d7 | 1657 | |
b250e837 | 1658 | dup2(config_s[1], REEXEC_CONFIG_PASS_FD); |
b9a549d7 | 1659 | close(config_s[1]); |
ad148c04 | 1660 | if (startup_pipe != -1) |
1661 | close(startup_pipe); | |
b250e837 | 1662 | |
b9a549d7 | 1663 | execv(rexec_argv[0], rexec_argv); |
1664 | ||
1665 | /* Reexec has failed, fall back and continue */ | |
1666 | error("rexec of %s failed: %s", rexec_argv[0], strerror(errno)); | |
b250e837 | 1667 | recv_rexec_state(REEXEC_CONFIG_PASS_FD, NULL); |
b9a549d7 | 1668 | log_init(__progname, options.log_level, |
1669 | options.log_facility, log_stderr); | |
1670 | ||
1671 | /* Clean up fds */ | |
b250e837 | 1672 | startup_pipe = REEXEC_STARTUP_PIPE_FD; |
b9a549d7 | 1673 | close(config_s[1]); |
b250e837 | 1674 | close(REEXEC_CONFIG_PASS_FD); |
1675 | newsock = sock_out = sock_in = dup(STDIN_FILENO); | |
b9a549d7 | 1676 | if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { |
1677 | dup2(fd, STDIN_FILENO); | |
1678 | dup2(fd, STDOUT_FILENO); | |
1679 | if (fd > STDERR_FILENO) | |
1680 | close(fd); | |
1681 | } | |
b250e837 | 1682 | debug("rexec cleanup in %d out %d newsock %d pipe %d sock %d", |
1683 | sock_in, sock_out, newsock, startup_pipe, config_s[0]); | |
b9a549d7 | 1684 | } |
1685 | ||
aa3378df | 1686 | /* |
1687 | * Disable the key regeneration alarm. We will not regenerate the | |
1688 | * key since we are no longer in a position to give it to anyone. We | |
1689 | * will not restart on SIGHUP since it no longer makes sense. | |
1690 | */ | |
5260325f | 1691 | alarm(0); |
1692 | signal(SIGALRM, SIG_DFL); | |
1693 | signal(SIGHUP, SIG_DFL); | |
1694 | signal(SIGTERM, SIG_DFL); | |
1695 | signal(SIGQUIT, SIG_DFL); | |
1696 | signal(SIGCHLD, SIG_DFL); | |
9aaf9be4 | 1697 | signal(SIGINT, SIG_DFL); |
5260325f | 1698 | |
aa3378df | 1699 | /* |
1700 | * Register our connection. This turns encryption off because we do | |
1701 | * not have a key. | |
1702 | */ | |
5260325f | 1703 | packet_set_connection(sock_in, sock_out); |
07200973 | 1704 | packet_set_server(); |
5260325f | 1705 | |
7c3bc5a2 | 1706 | /* Set SO_KEEPALIVE if requested. */ |
1707 | if (options.tcp_keep_alive && packet_connection_is_on_socket() && | |
1708 | setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) < 0) | |
1709 | error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); | |
1710 | ||
29798ed0 | 1711 | if ((remote_port = get_remote_port()) < 0) { |
1712 | debug("get_remote_port failed"); | |
1713 | cleanup_exit(255); | |
1714 | } | |
3a85986d | 1715 | |
1716 | /* | |
1717 | * We use get_canonical_hostname with usedns = 0 instead of | |
1718 | * get_remote_ipaddr here so IP options will be checked. | |
1719 | */ | |
211f229e | 1720 | (void) get_canonical_hostname(0); |
1721 | /* | |
1722 | * The rest of the code depends on the fact that | |
1723 | * get_remote_ipaddr() caches the remote ip, even if | |
1724 | * the socket goes away. | |
1725 | */ | |
1726 | remote_ip = get_remote_ipaddr(); | |
5260325f | 1727 | |
6039eeef | 1728 | #ifdef SSH_AUDIT_EVENTS |
c00e4d75 | 1729 | audit_connection_from(remote_ip, remote_port); |
1730 | #endif | |
5260325f | 1731 | #ifdef LIBWRAP |
ac28afd8 | 1732 | /* Check whether logins are denied from this host. */ |
33e5359c | 1733 | if (packet_connection_is_on_socket()) { |
5260325f | 1734 | struct request_info req; |
8efc0c15 | 1735 | |
8fbc356d | 1736 | request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0); |
5260325f | 1737 | fromhost(&req); |
8efc0c15 | 1738 | |
5260325f | 1739 | if (!hosts_access(&req)) { |
ac28afd8 | 1740 | debug("Connection refused by tcp wrapper"); |
563834bb | 1741 | refuse(&req); |
ac28afd8 | 1742 | /* NOTREACHED */ |
1743 | fatal("libwrap refuse returns"); | |
5260325f | 1744 | } |
8efc0c15 | 1745 | } |
48e671d5 | 1746 | #endif /* LIBWRAP */ |
ac28afd8 | 1747 | |
5260325f | 1748 | /* Log the connection. */ |
1749 | verbose("Connection from %.500s port %d", remote_ip, remote_port); | |
8efc0c15 | 1750 | |
aa3378df | 1751 | /* |
7b9b0103 | 1752 | * We don't want to listen forever unless the other side |
aa3378df | 1753 | * successfully authenticates itself. So we set up an alarm which is |
1754 | * cleared after successful authentication. A limit of zero | |
7b9b0103 | 1755 | * indicates no limit. Note that we don't set the alarm in debugging |
aa3378df | 1756 | * mode; it is just annoying to have the server exit just when you |
1757 | * are about to discover the bug. | |
1758 | */ | |
f00d1f78 | 1759 | signal(SIGALRM, grace_alarm_handler); |
5260325f | 1760 | if (!debug_flag) |
1761 | alarm(options.login_grace_time); | |
1762 | ||
7368a6c8 | 1763 | sshd_exchange_identification(sock_in, sock_out); |
0598d99d | 1764 | |
5260325f | 1765 | packet_set_nonblocking(); |
1766 | ||
2362db19 | 1767 | /* allocate authentication context */ |
52e3daed | 1768 | authctxt = xcalloc(1, sizeof(*authctxt)); |
2362db19 | 1769 | |
1b394137 | 1770 | authctxt->loginmsg = &loginmsg; |
1771 | ||
2362db19 | 1772 | /* XXX global for cleanup, access from other modules */ |
1773 | the_authctxt = authctxt; | |
1774 | ||
022487ce | 1775 | /* prepare buffer to collect messages to display to user after login */ |
1776 | buffer_init(&loginmsg); | |
1777 | ||
324bf712 | 1778 | if (use_privsep) |
2362db19 | 1779 | if (privsep_preauth(authctxt) == 1) |
324bf712 | 1780 | goto authenticated; |
1853d1ef | 1781 | |
7b2ea3a1 | 1782 | /* perform the key exchange */ |
7b2ea3a1 | 1783 | /* authenticate user and start session */ |
e78a59f5 | 1784 | if (compat20) { |
1785 | do_ssh2_kex(); | |
2362db19 | 1786 | do_authentication2(authctxt); |
e78a59f5 | 1787 | } else { |
1788 | do_ssh1_kex(); | |
2362db19 | 1789 | do_authentication(authctxt); |
e78a59f5 | 1790 | } |
324bf712 | 1791 | /* |
1792 | * If we use privilege separation, the unprivileged child transfers | |
1793 | * the current keystate and exits | |
1794 | */ | |
1795 | if (use_privsep) { | |
b5a28cbc | 1796 | mm_send_keystate(pmonitor); |
1853d1ef | 1797 | exit(0); |
324bf712 | 1798 | } |
1853d1ef | 1799 | |
1800 | authenticated: | |
678143bd | 1801 | /* |
1802 | * Cancel the alarm we set to limit the time taken for | |
1803 | * authentication. | |
1804 | */ | |
1805 | alarm(0); | |
1806 | signal(SIGALRM, SIG_DFL); | |
184cb418 | 1807 | authctxt->authenticated = 1; |
678143bd | 1808 | if (startup_pipe != -1) { |
1809 | close(startup_pipe); | |
1810 | startup_pipe = -1; | |
1811 | } | |
1812 | ||
6039eeef | 1813 | #ifdef SSH_AUDIT_EVENTS |
1814 | audit_event(SSH_AUTH_SUCCESS); | |
c00e4d75 | 1815 | #endif |
1816 | ||
762715ce | 1817 | /* |
1853d1ef | 1818 | * In privilege separation, we fork another child and prepare |
1819 | * file descriptor passing. | |
1820 | */ | |
1821 | if (use_privsep) { | |
324bf712 | 1822 | privsep_postauth(authctxt); |
1823 | /* the monitor process [priv] will not return */ | |
1853d1ef | 1824 | if (!compat20) |
1825 | destroy_sensitive_data(); | |
1826 | } | |
1b34c1b3 | 1827 | |
2362db19 | 1828 | /* Start session. */ |
1b34c1b3 | 1829 | do_authenticated(authctxt); |
1830 | ||
63284fbb | 1831 | /* The connection has been terminated. */ |
1832 | verbose("Closing connection to %.100s", remote_ip); | |
8efc0c15 | 1833 | |
d94aa2ae | 1834 | #ifdef USE_PAM |
7fceb20d | 1835 | if (options.use_pam) |
1836 | finish_pam(); | |
d94aa2ae | 1837 | #endif /* USE_PAM */ |
8efc0c15 | 1838 | |
2b0c0925 | 1839 | #ifdef SSH_AUDIT_EVENTS |
1840 | PRIVSEP(audit_event(SSH_CONNECTION_CLOSE)); | |
1841 | #endif | |
1842 | ||
5260325f | 1843 | packet_close(); |
1853d1ef | 1844 | |
1845 | if (use_privsep) | |
1846 | mm_terminate(); | |
1847 | ||
5260325f | 1848 | exit(0); |
1849 | } | |
8efc0c15 | 1850 | |
4f08e98d | 1851 | /* |
1852 | * Decrypt session_key_int using our private server key and private host key | |
1853 | * (key with larger modulus first). | |
1854 | */ | |
1853d1ef | 1855 | int |
4f08e98d | 1856 | ssh1_session_key(BIGNUM *session_key_int) |
1857 | { | |
1858 | int rsafail = 0; | |
1859 | ||
3efa8ea9 | 1860 | if (BN_cmp(sensitive_data.server_key->rsa->n, |
1861 | sensitive_data.ssh1_host_key->rsa->n) > 0) { | |
4f08e98d | 1862 | /* Server key has bigger modulus. */ |
1863 | if (BN_num_bits(sensitive_data.server_key->rsa->n) < | |
3efa8ea9 | 1864 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + |
1865 | SSH_KEY_BITS_RESERVED) { | |
1866 | fatal("do_connection: %s: " | |
1867 | "server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d", | |
4f08e98d | 1868 | get_remote_ipaddr(), |
1869 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
1870 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), | |
1871 | SSH_KEY_BITS_RESERVED); | |
1872 | } | |
1873 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1874 | sensitive_data.server_key->rsa) <= 0) | |
1875 | rsafail++; | |
1876 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1877 | sensitive_data.ssh1_host_key->rsa) <= 0) | |
1878 | rsafail++; | |
1879 | } else { | |
1880 | /* Host key has bigger modulus (or they are equal). */ | |
1881 | if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) < | |
3efa8ea9 | 1882 | BN_num_bits(sensitive_data.server_key->rsa->n) + |
1883 | SSH_KEY_BITS_RESERVED) { | |
1884 | fatal("do_connection: %s: " | |
1885 | "host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d", | |
4f08e98d | 1886 | get_remote_ipaddr(), |
1887 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), | |
1888 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
1889 | SSH_KEY_BITS_RESERVED); | |
1890 | } | |
1891 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1892 | sensitive_data.ssh1_host_key->rsa) < 0) | |
1893 | rsafail++; | |
1894 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1895 | sensitive_data.server_key->rsa) < 0) | |
1896 | rsafail++; | |
1897 | } | |
1898 | return (rsafail); | |
1899 | } | |
5260325f | 1900 | /* |
7b2ea3a1 | 1901 | * SSH1 key exchange |
5260325f | 1902 | */ |
396c147e | 1903 | static void |
1e3b8b07 | 1904 | do_ssh1_kex(void) |
8efc0c15 | 1905 | { |
5260325f | 1906 | int i, len; |
46aa2d1f | 1907 | int rsafail = 0; |
5260325f | 1908 | BIGNUM *session_key_int; |
1e3b8b07 | 1909 | u_char session_key[SSH_SESSION_KEY_LENGTH]; |
1910 | u_char cookie[8]; | |
1911 | u_int cipher_type, auth_mask, protocol_flags; | |
7fdc56c5 | 1912 | u_int32_t rnd = 0; |
5260325f | 1913 | |
aa3378df | 1914 | /* |
1915 | * Generate check bytes that the client must send back in the user | |
1916 | * packet in order for it to be accepted; this is used to defy ip | |
1917 | * spoofing attacks. Note that this only works against somebody | |
1918 | * doing IP spoofing from a remote machine; any machine on the local | |
1919 | * network can still see outgoing packets and catch the random | |
1920 | * cookie. This only affects rhosts authentication, and this is one | |
1921 | * of the reasons why it is inherently insecure. | |
1922 | */ | |
5260325f | 1923 | for (i = 0; i < 8; i++) { |
1924 | if (i % 4 == 0) | |
7fdc56c5 | 1925 | rnd = arc4random(); |
1926 | cookie[i] = rnd & 0xff; | |
1927 | rnd >>= 8; | |
5260325f | 1928 | } |
1929 | ||
aa3378df | 1930 | /* |
1931 | * Send our public key. We include in the packet 64 bits of random | |
1932 | * data that must be matched in the reply in order to prevent IP | |
1933 | * spoofing. | |
1934 | */ | |
5260325f | 1935 | packet_start(SSH_SMSG_PUBLIC_KEY); |
1936 | for (i = 0; i < 8; i++) | |
7b2ea3a1 | 1937 | packet_put_char(cookie[i]); |
5260325f | 1938 | |
1939 | /* Store our public server RSA key. */ | |
fa08c86b | 1940 | packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n)); |
1941 | packet_put_bignum(sensitive_data.server_key->rsa->e); | |
1942 | packet_put_bignum(sensitive_data.server_key->rsa->n); | |
5260325f | 1943 | |
1944 | /* Store our public host RSA key. */ | |
fa08c86b | 1945 | packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); |
1946 | packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e); | |
1947 | packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n); | |
5260325f | 1948 | |
1949 | /* Put protocol flags. */ | |
1950 | packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN); | |
1951 | ||
1952 | /* Declare which ciphers we support. */ | |
94ec8c6b | 1953 | packet_put_int(cipher_mask_ssh1(0)); |
5260325f | 1954 | |
1955 | /* Declare supported authentication types. */ | |
1956 | auth_mask = 0; | |
5260325f | 1957 | if (options.rhosts_rsa_authentication) |
1958 | auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA; | |
1959 | if (options.rsa_authentication) | |
1960 | auth_mask |= 1 << SSH_AUTH_RSA; | |
5ba55ada | 1961 | if (options.challenge_response_authentication == 1) |
5260325f | 1962 | auth_mask |= 1 << SSH_AUTH_TIS; |
5260325f | 1963 | if (options.password_authentication) |
1964 | auth_mask |= 1 << SSH_AUTH_PASSWORD; | |
1965 | packet_put_int(auth_mask); | |
1966 | ||
1967 | /* Send the packet and wait for it to be sent. */ | |
1968 | packet_send(); | |
1969 | packet_write_wait(); | |
1970 | ||
fa08c86b | 1971 | debug("Sent %d bit server key and %d bit host key.", |
1972 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
1973 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); | |
5260325f | 1974 | |
1975 | /* Read clients reply (cipher type and session key). */ | |
54a5250f | 1976 | packet_read_expect(SSH_CMSG_SESSION_KEY); |
5260325f | 1977 | |
2d86a6cc | 1978 | /* Get cipher type and check whether we accept this. */ |
5260325f | 1979 | cipher_type = packet_get_char(); |
1980 | ||
94ec8c6b | 1981 | if (!(cipher_mask_ssh1(0) & (1 << cipher_type))) |
2d86a6cc | 1982 | packet_disconnect("Warning: client selects unsupported cipher."); |
1983 | ||
5260325f | 1984 | /* Get check bytes from the packet. These must match those we |
1985 | sent earlier with the public key packet. */ | |
1986 | for (i = 0; i < 8; i++) | |
7b2ea3a1 | 1987 | if (cookie[i] != packet_get_char()) |
5260325f | 1988 | packet_disconnect("IP Spoofing check bytes do not match."); |
1989 | ||
1990 | debug("Encryption type: %.200s", cipher_name(cipher_type)); | |
1991 | ||
1992 | /* Get the encrypted integer. */ | |
b775c6f2 | 1993 | if ((session_key_int = BN_new()) == NULL) |
1994 | fatal("do_ssh1_kex: BN_new failed"); | |
20b279e6 | 1995 | packet_get_bignum(session_key_int); |
5260325f | 1996 | |
5260325f | 1997 | protocol_flags = packet_get_int(); |
1998 | packet_set_protocol_flags(protocol_flags); | |
95500969 | 1999 | packet_check_eom(); |
5260325f | 2000 | |
4f08e98d | 2001 | /* Decrypt session_key_int using host/server keys */ |
1853d1ef | 2002 | rsafail = PRIVSEP(ssh1_session_key(session_key_int)); |
2003 | ||
aa3378df | 2004 | /* |
2005 | * Extract session key from the decrypted integer. The key is in the | |
2006 | * least significant 256 bits of the integer; the first byte of the | |
2007 | * key is in the highest bits. | |
2008 | */ | |
46aa2d1f | 2009 | if (!rsafail) { |
2010 | BN_mask_bits(session_key_int, sizeof(session_key) * 8); | |
2011 | len = BN_num_bytes(session_key_int); | |
2ceb8101 | 2012 | if (len < 0 || (u_int)len > sizeof(session_key)) { |
46aa2d1f | 2013 | error("do_connection: bad session key len from %s: " |
5ca51e19 | 2014 | "session_key_int %d > sizeof(session_key) %lu", |
2015 | get_remote_ipaddr(), len, (u_long)sizeof(session_key)); | |
46aa2d1f | 2016 | rsafail++; |
2017 | } else { | |
2018 | memset(session_key, 0, sizeof(session_key)); | |
2019 | BN_bn2bin(session_key_int, | |
2020 | session_key + sizeof(session_key) - len); | |
00be5382 | 2021 | |
8bbf1fa6 | 2022 | derive_ssh1_session_id( |
f2107e97 | 2023 | sensitive_data.ssh1_host_key->rsa->n, |
8bbf1fa6 | 2024 | sensitive_data.server_key->rsa->n, |
2025 | cookie, session_id); | |
00be5382 | 2026 | /* |
2027 | * Xor the first 16 bytes of the session key with the | |
2028 | * session id. | |
2029 | */ | |
2030 | for (i = 0; i < 16; i++) | |
2031 | session_key[i] ^= session_id[i]; | |
46aa2d1f | 2032 | } |
2033 | } | |
2034 | if (rsafail) { | |
00be5382 | 2035 | int bytes = BN_num_bytes(session_key_int); |
f6b1ba8f | 2036 | u_char *buf = xmalloc(bytes); |
00be5382 | 2037 | MD5_CTX md; |
2038 | ||
bbe88b6d | 2039 | logit("do_connection: generating a fake encryption key"); |
00be5382 | 2040 | BN_bn2bin(session_key_int, buf); |
2041 | MD5_Init(&md); | |
2042 | MD5_Update(&md, buf, bytes); | |
2043 | MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); | |
2044 | MD5_Final(session_key, &md); | |
2045 | MD5_Init(&md); | |
2046 | MD5_Update(&md, session_key, 16); | |
2047 | MD5_Update(&md, buf, bytes); | |
2048 | MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); | |
2049 | MD5_Final(session_key + 16, &md); | |
2050 | memset(buf, 0, bytes); | |
2051 | xfree(buf); | |
0572fe75 | 2052 | for (i = 0; i < 16; i++) |
2053 | session_id[i] = session_key[i] ^ session_key[i + 16]; | |
46aa2d1f | 2054 | } |
1853d1ef | 2055 | /* Destroy the private and public keys. No longer. */ |
63284fbb | 2056 | destroy_sensitive_data(); |
00be5382 | 2057 | |
1853d1ef | 2058 | if (use_privsep) |
2059 | mm_ssh1_session_id(session_id); | |
2060 | ||
7b2ea3a1 | 2061 | /* Destroy the decrypted integer. It is no longer needed. */ |
2062 | BN_clear_free(session_key_int); | |
2063 | ||
5260325f | 2064 | /* Set the session key. From this on all communications will be encrypted. */ |
2065 | packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type); | |
2066 | ||
2067 | /* Destroy our copy of the session key. It is no longer needed. */ | |
2068 | memset(session_key, 0, sizeof(session_key)); | |
2069 | ||
2070 | debug("Received session key; encryption turned on."); | |
2071 | ||
c242fc96 | 2072 | /* Send an acknowledgment packet. Note that this packet is sent encrypted. */ |
5260325f | 2073 | packet_start(SSH_SMSG_SUCCESS); |
2074 | packet_send(); | |
2075 | packet_write_wait(); | |
5260325f | 2076 | } |
e78a59f5 | 2077 | |
2078 | /* | |
2079 | * SSH2 key exchange: diffie-hellman-group1-sha1 | |
2080 | */ | |
396c147e | 2081 | static void |
1e3b8b07 | 2082 | do_ssh2_kex(void) |
e78a59f5 | 2083 | { |
e78a59f5 | 2084 | Kex *kex; |
e78a59f5 | 2085 | |
a8be9f80 | 2086 | if (options.ciphers != NULL) { |
6ae2364d | 2087 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = |
a8be9f80 | 2088 | myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; |
2089 | } | |
1ad64a93 | 2090 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = |
2091 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]); | |
2092 | myproposal[PROPOSAL_ENC_ALGS_STOC] = | |
2093 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); | |
2094 | ||
b2552997 | 2095 | if (options.macs != NULL) { |
2096 | myproposal[PROPOSAL_MAC_ALGS_CTOS] = | |
2097 | myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; | |
2098 | } | |
07200973 | 2099 | if (options.compression == COMP_NONE) { |
636f76ca | 2100 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = |
2101 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "none"; | |
07200973 | 2102 | } else if (options.compression == COMP_DELAYED) { |
2103 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = | |
2104 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com"; | |
636f76ca | 2105 | } |
3efa8ea9 | 2106 | |
fa08c86b | 2107 | myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = list_hostkey_types(); |
2108 | ||
7a37c112 | 2109 | /* start key exchange */ |
d8ee838b | 2110 | kex = kex_setup(myproposal); |
98a58eda | 2111 | kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server; |
41e5bd9a | 2112 | kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server; |
98a58eda | 2113 | kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; |
2ff8003a | 2114 | kex->kex[KEX_DH_GEX_SHA256] = kexgex_server; |
a5c9ffdb | 2115 | kex->server = 1; |
2116 | kex->client_version_string=client_version_string; | |
2117 | kex->server_version_string=server_version_string; | |
2118 | kex->load_host_key=&get_hostkey_by_type; | |
1853d1ef | 2119 | kex->host_key_index=&get_hostkey_index; |
94ec8c6b | 2120 | |
7a37c112 | 2121 | xxx_kex = kex; |
2122 | ||
c422989b | 2123 | dispatch_run(DISPATCH_BLOCK, &kex->done, kex); |
94ec8c6b | 2124 | |
d1ac6175 | 2125 | session_id2 = kex->session_id; |
2126 | session_id2_len = kex->session_id_len; | |
2127 | ||
94ec8c6b | 2128 | #ifdef DEBUG_KEXDH |
2129 | /* send 1st encrypted/maced/compressed message */ | |
2130 | packet_start(SSH2_MSG_IGNORE); | |
2131 | packet_put_cstring("markus"); | |
2132 | packet_send(); | |
2133 | packet_write_wait(); | |
2134 | #endif | |
a5c9ffdb | 2135 | debug("KEX done"); |
e78a59f5 | 2136 | } |
2362db19 | 2137 | |
2138 | /* server specific fatal cleanup */ | |
2139 | void | |
2140 | cleanup_exit(int i) | |
2141 | { | |
2142 | if (the_authctxt) | |
2143 | do_cleanup(the_authctxt); | |
6039eeef | 2144 | #ifdef SSH_AUDIT_EVENTS |
c00e4d75 | 2145 | /* done after do_cleanup so it can cancel the PAM auth 'thread' */ |
2146 | if (!use_privsep || mm_is_monitor()) | |
6039eeef | 2147 | audit_event(SSH_CONNECTION_ABANDON); |
c00e4d75 | 2148 | #endif |
2362db19 | 2149 | _exit(i); |
2150 | } |