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08427260 | 1 | /* $OpenBSD: sshd.c,v 1.372 2010/01/29 00:20:41 djm 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" |
3593bdc0 | 57 | #include "openbsd-compat/sys-queue.h" |
aa2eae64 | 58 | #include <sys/wait.h> |
a75f5360 | 59 | |
028094f4 | 60 | #include <errno.h> |
d3221cca | 61 | #include <fcntl.h> |
28cb0a43 | 62 | #include <netdb.h> |
b5b88c19 | 63 | #ifdef HAVE_PATHS_H |
a75f5360 | 64 | #include <paths.h> |
b5b88c19 | 65 | #endif |
22bbb3e6 | 66 | #include <grp.h> |
b1842393 | 67 | #include <pwd.h> |
ada68823 | 68 | #include <signal.h> |
24436b92 | 69 | #include <stdarg.h> |
cf851879 | 70 | #include <stdio.h> |
ffa517a8 | 71 | #include <stdlib.h> |
00146caa | 72 | #include <string.h> |
00a017bd | 73 | #include <unistd.h> |
8efc0c15 | 74 | |
42f11eb2 | 75 | #include <openssl/dh.h> |
76 | #include <openssl/bn.h> | |
436c347c | 77 | #include <openssl/md5.h> |
1853d1ef | 78 | #include <openssl/rand.h> |
f5f25d17 | 79 | #include "openbsd-compat/openssl-compat.h" |
80 | ||
6e879cb4 | 81 | #ifdef HAVE_SECUREWARE |
82 | #include <sys/security.h> | |
83 | #include <prot.h> | |
84 | #endif | |
42f11eb2 | 85 | |
31652869 | 86 | #include "xmalloc.h" |
42f11eb2 | 87 | #include "ssh.h" |
88 | #include "ssh1.h" | |
89 | #include "ssh2.h" | |
8efc0c15 | 90 | #include "rsa.h" |
1729c161 | 91 | #include "sshpty.h" |
8efc0c15 | 92 | #include "packet.h" |
42f11eb2 | 93 | #include "log.h" |
31652869 | 94 | #include "buffer.h" |
8efc0c15 | 95 | #include "servconf.h" |
96 | #include "uidswap.h" | |
97 | #include "compat.h" | |
42f11eb2 | 98 | #include "cipher.h" |
7368a6c8 | 99 | #include "key.h" |
31652869 | 100 | #include "kex.h" |
94ec8c6b | 101 | #include "dh.h" |
e78a59f5 | 102 | #include "myproposal.h" |
a306f2dd | 103 | #include "authfile.h" |
42f11eb2 | 104 | #include "pathnames.h" |
105 | #include "atomicio.h" | |
106 | #include "canohost.h" | |
31652869 | 107 | #include "hostfile.h" |
42f11eb2 | 108 | #include "auth.h" |
109 | #include "misc.h" | |
b9a549d7 | 110 | #include "msg.h" |
a5c9ffdb | 111 | #include "dispatch.h" |
e4d7f734 | 112 | #include "channels.h" |
1b34c1b3 | 113 | #include "session.h" |
1853d1ef | 114 | #include "monitor_mm.h" |
115 | #include "monitor.h" | |
31652869 | 116 | #ifdef GSSAPI |
117 | #include "ssh-gss.h" | |
118 | #endif | |
1853d1ef | 119 | #include "monitor_wrap.h" |
d0137ef8 | 120 | #include "roaming.h" |
28015df4 | 121 | #include "version.h" |
8efc0c15 | 122 | |
123 | #ifdef LIBWRAP | |
124 | #include <tcpd.h> | |
125 | #include <syslog.h> | |
5c7fd4ce | 126 | int allow_severity; |
127 | int deny_severity; | |
8efc0c15 | 128 | #endif /* LIBWRAP */ |
129 | ||
130 | #ifndef O_NOCTTY | |
131 | #define O_NOCTTY 0 | |
132 | #endif | |
133 | ||
b250e837 | 134 | /* Re-exec fds */ |
135 | #define REEXEC_DEVCRYPTO_RESERVED_FD (STDERR_FILENO + 1) | |
136 | #define REEXEC_STARTUP_PIPE_FD (STDERR_FILENO + 2) | |
137 | #define REEXEC_CONFIG_PASS_FD (STDERR_FILENO + 3) | |
138 | #define REEXEC_MIN_FREE_FD (STDERR_FILENO + 4) | |
139 | ||
260d427b | 140 | extern char *__progname; |
260d427b | 141 | |
8efc0c15 | 142 | /* Server configuration options. */ |
143 | ServerOptions options; | |
144 | ||
145 | /* Name of the server configuration file. */ | |
42f11eb2 | 146 | char *config_file_name = _PATH_SERVER_CONFIG_FILE; |
8efc0c15 | 147 | |
5260325f | 148 | /* |
149 | * Debug mode flag. This can be set on the command line. If debug | |
150 | * mode is enabled, extra debugging output will be sent to the system | |
151 | * log, the daemon will not go to background, and will exit after processing | |
152 | * the first connection. | |
153 | */ | |
8efc0c15 | 154 | int debug_flag = 0; |
155 | ||
f87f09aa | 156 | /* Flag indicating that the daemon should only test the configuration and keys. */ |
157 | int test_flag = 0; | |
158 | ||
8efc0c15 | 159 | /* Flag indicating that the daemon is being started from inetd. */ |
160 | int inetd_flag = 0; | |
161 | ||
0b6fbf03 | 162 | /* Flag indicating that sshd should not detach and become a daemon. */ |
163 | int no_daemon_flag = 0; | |
164 | ||
6a17f9c2 | 165 | /* debug goes to stderr unless inetd_flag is set */ |
166 | int log_stderr = 0; | |
167 | ||
8efc0c15 | 168 | /* Saved arguments to main(). */ |
169 | char **saved_argv; | |
4d33e531 | 170 | int saved_argc; |
8efc0c15 | 171 | |
b9a549d7 | 172 | /* re-exec */ |
173 | int rexeced_flag = 0; | |
174 | int rexec_flag = 1; | |
175 | int rexec_argc = 0; | |
176 | char **rexec_argv; | |
177 | ||
aa3378df | 178 | /* |
48e671d5 | 179 | * The sockets that the server is listening; this is used in the SIGHUP |
180 | * signal handler. | |
aa3378df | 181 | */ |
48e671d5 | 182 | #define MAX_LISTEN_SOCKS 16 |
183 | int listen_socks[MAX_LISTEN_SOCKS]; | |
184 | int num_listen_socks = 0; | |
8efc0c15 | 185 | |
aa3378df | 186 | /* |
187 | * the client's version string, passed by sshd2 in compat mode. if != NULL, | |
188 | * sshd will skip the version-number exchange | |
189 | */ | |
5260325f | 190 | char *client_version_string = NULL; |
7368a6c8 | 191 | char *server_version_string = NULL; |
8efc0c15 | 192 | |
7a37c112 | 193 | /* for rekeying XXX fixme */ |
194 | Kex *xxx_kex; | |
195 | ||
aa3378df | 196 | /* |
197 | * Any really sensitive data in the application is contained in this | |
198 | * structure. The idea is that this structure could be locked into memory so | |
199 | * that the pages do not get written into swap. However, there are some | |
200 | * problems. The private key contains BIGNUMs, and we do not (in principle) | |
201 | * have access to the internals of them, and locking just the structure is | |
202 | * not very useful. Currently, memory locking is not implemented. | |
203 | */ | |
5260325f | 204 | struct { |
cb7bd922 | 205 | Key *server_key; /* ephemeral server key */ |
fa08c86b | 206 | Key *ssh1_host_key; /* ssh1 host key */ |
207 | Key **host_keys; /* all private host keys */ | |
208 | int have_ssh1_key; | |
209 | int have_ssh2_key; | |
00be5382 | 210 | u_char ssh1_cookie[SSH_SESSION_KEY_LENGTH]; |
8efc0c15 | 211 | } sensitive_data; |
212 | ||
aa3378df | 213 | /* |
59c97189 | 214 | * Flag indicating whether the RSA server key needs to be regenerated. |
215 | * Is set in the SIGALRM handler and cleared when the key is regenerated. | |
aa3378df | 216 | */ |
7a934d1b | 217 | static volatile sig_atomic_t key_do_regen = 0; |
8efc0c15 | 218 | |
c9130033 | 219 | /* This is set to true when a signal is received. */ |
7a934d1b | 220 | static volatile sig_atomic_t received_sighup = 0; |
221 | static volatile sig_atomic_t received_sigterm = 0; | |
8efc0c15 | 222 | |
7368a6c8 | 223 | /* session identifier, used by RSA-auth */ |
1e3b8b07 | 224 | u_char session_id[16]; |
e7c0f9d5 | 225 | |
a306f2dd | 226 | /* same for ssh2 */ |
1e3b8b07 | 227 | u_char *session_id2 = NULL; |
a27002e5 | 228 | u_int session_id2_len = 0; |
a306f2dd | 229 | |
c345cf9d | 230 | /* record remote hostname or ip */ |
1e3b8b07 | 231 | u_int utmp_len = MAXHOSTNAMELEN; |
c345cf9d | 232 | |
7ace8c3b | 233 | /* options.max_startup sized array of fd ints */ |
234 | int *startup_pipes = NULL; | |
235 | int startup_pipe; /* in child */ | |
236 | ||
1853d1ef | 237 | /* variables used for privilege separation */ |
d231781a | 238 | int use_privsep = -1; |
a9b33b95 | 239 | struct monitor *pmonitor = NULL; |
1853d1ef | 240 | |
2362db19 | 241 | /* global authentication context */ |
242 | Authctxt *the_authctxt = NULL; | |
243 | ||
d231781a | 244 | /* sshd_config buffer */ |
245 | Buffer cfg; | |
246 | ||
be2ca0c9 | 247 | /* message to be displayed after login */ |
248 | Buffer loginmsg; | |
249 | ||
a078cbee | 250 | /* Unprivileged user */ |
251 | struct passwd *privsep_pw = NULL; | |
252 | ||
7368a6c8 | 253 | /* Prototypes for various functions defined later in this file. */ |
396c147e | 254 | void destroy_sensitive_data(void); |
1853d1ef | 255 | void demote_sensitive_data(void); |
c8d54615 | 256 | |
396c147e | 257 | static void do_ssh1_kex(void); |
258 | static void do_ssh2_kex(void); | |
94ec8c6b | 259 | |
48e671d5 | 260 | /* |
261 | * Close all listening sockets | |
262 | */ | |
396c147e | 263 | static void |
48e671d5 | 264 | close_listen_socks(void) |
265 | { | |
266 | int i; | |
e424e241 | 267 | |
48e671d5 | 268 | for (i = 0; i < num_listen_socks; i++) |
269 | close(listen_socks[i]); | |
270 | num_listen_socks = -1; | |
271 | } | |
272 | ||
7ace8c3b | 273 | static void |
274 | close_startup_pipes(void) | |
275 | { | |
276 | int i; | |
e424e241 | 277 | |
7ace8c3b | 278 | if (startup_pipes) |
279 | for (i = 0; i < options.max_startups; i++) | |
280 | if (startup_pipes[i] != -1) | |
281 | close(startup_pipes[i]); | |
282 | } | |
283 | ||
5260325f | 284 | /* |
285 | * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP; | |
286 | * the effect is to reread the configuration file (and to regenerate | |
287 | * the server key). | |
288 | */ | |
3efa8ea9 | 289 | |
290 | /*ARGSUSED*/ | |
396c147e | 291 | static void |
5260325f | 292 | sighup_handler(int sig) |
8efc0c15 | 293 | { |
6056eb35 | 294 | int save_errno = errno; |
295 | ||
5260325f | 296 | received_sighup = 1; |
297 | signal(SIGHUP, sighup_handler); | |
6056eb35 | 298 | errno = save_errno; |
8efc0c15 | 299 | } |
300 | ||
5260325f | 301 | /* |
302 | * Called from the main program after receiving SIGHUP. | |
303 | * Restarts the server. | |
304 | */ | |
396c147e | 305 | static void |
5ca51e19 | 306 | sighup_restart(void) |
8efc0c15 | 307 | { |
bbe88b6d | 308 | logit("Received SIGHUP; restarting."); |
48e671d5 | 309 | close_listen_socks(); |
7ace8c3b | 310 | close_startup_pipes(); |
1e823acf | 311 | alarm(0); /* alarm timer persists across exec */ |
1e0e398c | 312 | signal(SIGHUP, SIG_IGN); /* will be restored after exec */ |
5260325f | 313 | execv(saved_argv[0], saved_argv); |
bbe88b6d | 314 | logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0], |
e424e241 | 315 | strerror(errno)); |
5260325f | 316 | exit(1); |
8efc0c15 | 317 | } |
318 | ||
5260325f | 319 | /* |
320 | * Generic signal handler for terminating signals in the master daemon. | |
5260325f | 321 | */ |
3efa8ea9 | 322 | /*ARGSUSED*/ |
396c147e | 323 | static void |
5260325f | 324 | sigterm_handler(int sig) |
8efc0c15 | 325 | { |
c9130033 | 326 | received_sigterm = sig; |
8efc0c15 | 327 | } |
328 | ||
5260325f | 329 | /* |
330 | * SIGCHLD handler. This is called whenever a child dies. This will then | |
c9130033 | 331 | * reap any zombies left by exited children. |
5260325f | 332 | */ |
3efa8ea9 | 333 | /*ARGSUSED*/ |
396c147e | 334 | static void |
5260325f | 335 | main_sigchld_handler(int sig) |
8efc0c15 | 336 | { |
5260325f | 337 | int save_errno = errno; |
e424e241 | 338 | pid_t pid; |
5260325f | 339 | int status; |
5ad13cd7 | 340 | |
8c38e88b | 341 | while ((pid = waitpid(-1, &status, WNOHANG)) > 0 || |
342 | (pid < 0 && errno == EINTR)) | |
5260325f | 343 | ; |
5ad13cd7 | 344 | |
5260325f | 345 | signal(SIGCHLD, main_sigchld_handler); |
346 | errno = save_errno; | |
8efc0c15 | 347 | } |
348 | ||
5260325f | 349 | /* |
350 | * Signal handler for the alarm after the login grace period has expired. | |
351 | */ | |
3efa8ea9 | 352 | /*ARGSUSED*/ |
396c147e | 353 | static void |
5260325f | 354 | grace_alarm_handler(int sig) |
8efc0c15 | 355 | { |
a9b33b95 | 356 | if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0) |
357 | kill(pmonitor->m_pid, SIGALRM); | |
358 | ||
5260325f | 359 | /* Log error and exit. */ |
28463427 | 360 | sigdie("Timeout before authentication for %s", get_remote_ipaddr()); |
5260325f | 361 | } |
8efc0c15 | 362 | |
5260325f | 363 | /* |
364 | * Signal handler for the key regeneration alarm. Note that this | |
365 | * alarm only occurs in the daemon waiting for connections, and it does not | |
366 | * do anything with the private key or random state before forking. | |
367 | * Thus there should be no concurrency control/asynchronous execution | |
368 | * problems. | |
369 | */ | |
396c147e | 370 | static void |
cb7bd922 | 371 | generate_ephemeral_server_key(void) |
fa08c86b | 372 | { |
cd332296 | 373 | verbose("Generating %s%d bit RSA key.", |
76ca7b01 | 374 | sensitive_data.server_key ? "new " : "", options.server_key_bits); |
fa08c86b | 375 | if (sensitive_data.server_key != NULL) |
376 | key_free(sensitive_data.server_key); | |
cd332296 | 377 | sensitive_data.server_key = key_generate(KEY_RSA1, |
76ca7b01 | 378 | options.server_key_bits); |
379 | verbose("RSA key generation complete."); | |
00be5382 | 380 | |
c1d152b8 | 381 | arc4random_buf(sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); |
00be5382 | 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; |
f9b45eaf | 403 | char *s, *newline = "\n"; |
7368a6c8 | 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; | |
f9b45eaf | 414 | newline = "\r\n"; |
a8be9f80 | 415 | } else { |
416 | major = PROTOCOL_MAJOR_1; | |
417 | minor = PROTOCOL_MINOR_1; | |
418 | } | |
f9b45eaf | 419 | snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s%s", major, minor, |
420 | SSH_VERSION, newline); | |
7368a6c8 | 421 | server_version_string = xstrdup(buf); |
422 | ||
7b390973 | 423 | /* Send our protocol version identification. */ |
d0137ef8 | 424 | if (roaming_atomicio(vwrite, sock_out, server_version_string, |
7b390973 | 425 | strlen(server_version_string)) |
426 | != strlen(server_version_string)) { | |
427 | logit("Could not write ident string to %s", get_remote_ipaddr()); | |
2362db19 | 428 | cleanup_exit(255); |
7b390973 | 429 | } |
430 | ||
431 | /* Read other sides version identification. */ | |
432 | memset(buf, 0, sizeof(buf)); | |
433 | for (i = 0; i < sizeof(buf) - 1; i++) { | |
d0137ef8 | 434 | if (roaming_atomicio(read, sock_in, &buf[i], 1) != 1) { |
7b390973 | 435 | logit("Did not receive identification string from %s", |
436 | get_remote_ipaddr()); | |
2362db19 | 437 | cleanup_exit(255); |
7368a6c8 | 438 | } |
7b390973 | 439 | if (buf[i] == '\r') { |
440 | buf[i] = 0; | |
441 | /* Kludge for F-Secure Macintosh < 1.0.2 */ | |
442 | if (i == 12 && | |
443 | strncmp(buf, "SSH-1.5-W1.0", 12) == 0) | |
7368a6c8 | 444 | break; |
7b390973 | 445 | continue; |
446 | } | |
447 | if (buf[i] == '\n') { | |
448 | buf[i] = 0; | |
449 | break; | |
7368a6c8 | 450 | } |
7368a6c8 | 451 | } |
7b390973 | 452 | buf[sizeof(buf) - 1] = 0; |
453 | client_version_string = xstrdup(buf); | |
7368a6c8 | 454 | |
455 | /* | |
456 | * Check that the versions match. In future this might accept | |
457 | * several versions and set appropriate flags to handle them. | |
458 | */ | |
459 | if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n", | |
460 | &remote_major, &remote_minor, remote_version) != 3) { | |
6ae2364d | 461 | s = "Protocol mismatch.\n"; |
dc54438a | 462 | (void) atomicio(vwrite, sock_out, s, strlen(s)); |
7368a6c8 | 463 | close(sock_in); |
464 | close(sock_out); | |
bbe88b6d | 465 | logit("Bad protocol version identification '%.100s' from %s", |
7368a6c8 | 466 | client_version_string, get_remote_ipaddr()); |
2362db19 | 467 | cleanup_exit(255); |
7368a6c8 | 468 | } |
469 | debug("Client protocol version %d.%d; client software version %.100s", | |
184eed6a | 470 | remote_major, remote_minor, remote_version); |
7368a6c8 | 471 | |
e78a59f5 | 472 | compat_datafellows(remote_version); |
473 | ||
9a87e2ac | 474 | if (datafellows & SSH_BUG_PROBE) { |
bbe88b6d | 475 | logit("probed from %s with %s. Don't panic.", |
9a87e2ac | 476 | get_remote_ipaddr(), client_version_string); |
2362db19 | 477 | cleanup_exit(255); |
9a87e2ac | 478 | } |
479 | ||
3a1c54d4 | 480 | if (datafellows & SSH_BUG_SCANNER) { |
bbe88b6d | 481 | logit("scanned from %s with %s. Don't panic.", |
3a1c54d4 | 482 | get_remote_ipaddr(), client_version_string); |
2362db19 | 483 | cleanup_exit(255); |
3a1c54d4 | 484 | } |
485 | ||
a8be9f80 | 486 | mismatch = 0; |
6aacefa7 | 487 | switch (remote_major) { |
7368a6c8 | 488 | case 1: |
a306f2dd | 489 | if (remote_minor == 99) { |
490 | if (options.protocol & SSH_PROTO_2) | |
491 | enable_compat20(); | |
492 | else | |
493 | mismatch = 1; | |
494 | break; | |
495 | } | |
a8be9f80 | 496 | if (!(options.protocol & SSH_PROTO_1)) { |
497 | mismatch = 1; | |
498 | break; | |
499 | } | |
7368a6c8 | 500 | if (remote_minor < 3) { |
089fbbd2 | 501 | packet_disconnect("Your ssh version is too old and " |
7368a6c8 | 502 | "is no longer supported. Please install a newer version."); |
503 | } else if (remote_minor == 3) { | |
504 | /* note that this disables agent-forwarding */ | |
505 | enable_compat13(); | |
506 | } | |
a8be9f80 | 507 | break; |
e78a59f5 | 508 | case 2: |
a8be9f80 | 509 | if (options.protocol & SSH_PROTO_2) { |
e78a59f5 | 510 | enable_compat20(); |
511 | break; | |
512 | } | |
513 | /* FALLTHROUGH */ | |
6ae2364d | 514 | default: |
a8be9f80 | 515 | mismatch = 1; |
516 | break; | |
517 | } | |
518 | chop(server_version_string); | |
a8be9f80 | 519 | debug("Local version string %.200s", server_version_string); |
520 | ||
521 | if (mismatch) { | |
7368a6c8 | 522 | s = "Protocol major versions differ.\n"; |
dc54438a | 523 | (void) atomicio(vwrite, sock_out, s, strlen(s)); |
7368a6c8 | 524 | close(sock_in); |
525 | close(sock_out); | |
bbe88b6d | 526 | logit("Protocol major versions differ for %s: %.200s vs. %.200s", |
a8be9f80 | 527 | get_remote_ipaddr(), |
528 | server_version_string, client_version_string); | |
2362db19 | 529 | cleanup_exit(255); |
7368a6c8 | 530 | } |
a306f2dd | 531 | } |
532 | ||
fa08c86b | 533 | /* Destroy the host and server keys. They will no longer be needed. */ |
a306f2dd | 534 | void |
535 | destroy_sensitive_data(void) | |
536 | { | |
fa08c86b | 537 | int i; |
538 | ||
539 | if (sensitive_data.server_key) { | |
540 | key_free(sensitive_data.server_key); | |
541 | sensitive_data.server_key = NULL; | |
542 | } | |
184eed6a | 543 | for (i = 0; i < options.num_host_key_files; i++) { |
fa08c86b | 544 | if (sensitive_data.host_keys[i]) { |
545 | key_free(sensitive_data.host_keys[i]); | |
546 | sensitive_data.host_keys[i] = NULL; | |
547 | } | |
548 | } | |
549 | sensitive_data.ssh1_host_key = NULL; | |
00be5382 | 550 | memset(sensitive_data.ssh1_cookie, 0, SSH_SESSION_KEY_LENGTH); |
fa08c86b | 551 | } |
fa08c86b | 552 | |
1853d1ef | 553 | /* Demote private to public keys for network child */ |
554 | void | |
555 | demote_sensitive_data(void) | |
556 | { | |
557 | Key *tmp; | |
558 | int i; | |
559 | ||
560 | if (sensitive_data.server_key) { | |
561 | tmp = key_demote(sensitive_data.server_key); | |
562 | key_free(sensitive_data.server_key); | |
563 | sensitive_data.server_key = tmp; | |
564 | } | |
565 | ||
566 | for (i = 0; i < options.num_host_key_files; i++) { | |
567 | if (sensitive_data.host_keys[i]) { | |
568 | tmp = key_demote(sensitive_data.host_keys[i]); | |
569 | key_free(sensitive_data.host_keys[i]); | |
570 | sensitive_data.host_keys[i] = tmp; | |
571 | if (tmp->type == KEY_RSA1) | |
572 | sensitive_data.ssh1_host_key = tmp; | |
573 | } | |
574 | } | |
575 | ||
576 | /* We do not clear ssh1_host key and cookie. XXX - Okay Niels? */ | |
577 | } | |
578 | ||
51aeb639 | 579 | static void |
1853d1ef | 580 | privsep_preauth_child(void) |
581 | { | |
c8dc0909 | 582 | u_int32_t rnd[256]; |
6ded293b | 583 | gid_t gidset[1]; |
1853d1ef | 584 | |
585 | /* Enable challenge-response authentication for privilege separation */ | |
586 | privsep_challenge_enable(); | |
587 | ||
3dfce5de | 588 | arc4random_stir(); |
c1d152b8 | 589 | arc4random_buf(rnd, sizeof(rnd)); |
7fdc56c5 | 590 | RAND_seed(rnd, sizeof(rnd)); |
1853d1ef | 591 | |
592 | /* Demote the private keys to public keys. */ | |
593 | demote_sensitive_data(); | |
594 | ||
343288b8 | 595 | /* Change our root directory */ |
1c352e97 | 596 | if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1) |
597 | fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR, | |
598 | strerror(errno)); | |
1853d1ef | 599 | if (chdir("/") == -1) |
edfb66cb | 600 | fatal("chdir(\"/\"): %s", strerror(errno)); |
762715ce | 601 | |
1853d1ef | 602 | /* Drop our privileges */ |
a078cbee | 603 | debug3("privsep user:group %u:%u", (u_int)privsep_pw->pw_uid, |
604 | (u_int)privsep_pw->pw_gid); | |
87809a1f | 605 | #if 0 |
6ff58a4b | 606 | /* XXX not ready, too heavy after chroot */ |
a078cbee | 607 | do_setusercontext(privsep_pw); |
87809a1f | 608 | #else |
a078cbee | 609 | gidset[0] = privsep_pw->pw_gid; |
87809a1f | 610 | if (setgroups(1, gidset) < 0) |
611 | fatal("setgroups: %.100s", strerror(errno)); | |
a078cbee | 612 | permanently_set_uid(privsep_pw); |
87809a1f | 613 | #endif |
1853d1ef | 614 | } |
615 | ||
2362db19 | 616 | static int |
617 | privsep_preauth(Authctxt *authctxt) | |
1853d1ef | 618 | { |
1853d1ef | 619 | int status; |
324bf712 | 620 | pid_t pid; |
1853d1ef | 621 | |
324bf712 | 622 | /* Set up unprivileged child process to deal with network data */ |
b5a28cbc | 623 | pmonitor = monitor_init(); |
324bf712 | 624 | /* Store a pointer to the kex for later rekeying */ |
b5a28cbc | 625 | pmonitor->m_pkex = &xxx_kex; |
324bf712 | 626 | |
627 | pid = fork(); | |
628 | if (pid == -1) { | |
629 | fatal("fork of unprivileged child failed"); | |
630 | } else if (pid != 0) { | |
c457707e | 631 | debug2("Network child is on pid %ld", (long)pid); |
324bf712 | 632 | |
b5a28cbc | 633 | close(pmonitor->m_recvfd); |
a9b33b95 | 634 | pmonitor->m_pid = pid; |
2362db19 | 635 | monitor_child_preauth(authctxt, pmonitor); |
b5a28cbc | 636 | close(pmonitor->m_sendfd); |
324bf712 | 637 | |
638 | /* Sync memory */ | |
b5a28cbc | 639 | monitor_sync(pmonitor); |
324bf712 | 640 | |
641 | /* Wait for the child's exit status */ | |
8c38e88b | 642 | while (waitpid(pid, &status, 0) < 0) |
643 | if (errno != EINTR) | |
644 | break; | |
2362db19 | 645 | return (1); |
324bf712 | 646 | } else { |
647 | /* child */ | |
648 | ||
b5a28cbc | 649 | close(pmonitor->m_sendfd); |
324bf712 | 650 | |
651 | /* Demote the child */ | |
652 | if (getuid() == 0 || geteuid() == 0) | |
653 | privsep_preauth_child(); | |
47c36e5b | 654 | setproctitle("%s", "[net]"); |
324bf712 | 655 | } |
2362db19 | 656 | return (0); |
324bf712 | 657 | } |
658 | ||
659 | static void | |
660 | privsep_postauth(Authctxt *authctxt) | |
661 | { | |
3dfce5de | 662 | u_int32_t rnd[256]; |
3dfce5de | 663 | |
94d8258b | 664 | #ifdef DISABLE_FD_PASSING |
d170feb1 | 665 | if (1) { |
666 | #else | |
1853d1ef | 667 | if (authctxt->pw->pw_uid == 0 || options.use_login) { |
d170feb1 | 668 | #endif |
1853d1ef | 669 | /* File descriptor passing is broken or root login */ |
1853d1ef | 670 | use_privsep = 0; |
ae25711b | 671 | goto skip; |
1853d1ef | 672 | } |
762715ce | 673 | |
1853d1ef | 674 | /* New socket pair */ |
b5a28cbc | 675 | monitor_reinit(pmonitor); |
1853d1ef | 676 | |
b5a28cbc | 677 | pmonitor->m_pid = fork(); |
678 | if (pmonitor->m_pid == -1) | |
1853d1ef | 679 | fatal("fork of unprivileged child failed"); |
b5a28cbc | 680 | else if (pmonitor->m_pid != 0) { |
e8e08a80 | 681 | verbose("User child is on pid %ld", (long)pmonitor->m_pid); |
b5a28cbc | 682 | close(pmonitor->m_recvfd); |
f143ed33 | 683 | buffer_clear(&loginmsg); |
b5a28cbc | 684 | monitor_child_postauth(pmonitor); |
1853d1ef | 685 | |
686 | /* NEVERREACHED */ | |
687 | exit(0); | |
688 | } | |
689 | ||
b5a28cbc | 690 | close(pmonitor->m_sendfd); |
1853d1ef | 691 | |
692 | /* Demote the private keys to public keys. */ | |
693 | demote_sensitive_data(); | |
694 | ||
3dfce5de | 695 | arc4random_stir(); |
c1d152b8 | 696 | arc4random_buf(rnd, sizeof(rnd)); |
3dfce5de | 697 | RAND_seed(rnd, sizeof(rnd)); |
698 | ||
1853d1ef | 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; |
c1d152b8 | 798 | r = arc4random_uniform(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, |
3b42e3ac | 810 | "usage: sshd [-46DdeiqTt] [-b bits] [-C connection_spec] [-f config_file]\n" |
811 | " [-g login_grace_time] [-h host_key_file] [-k key_gen_time]\n" | |
812 | " [-o option] [-p port] [-u len]\n" | |
65edde94 | 813 | ); |
2717fa0f | 814 | exit(1); |
815 | } | |
816 | ||
b9a549d7 | 817 | static void |
818 | send_rexec_state(int fd, Buffer *conf) | |
819 | { | |
820 | Buffer m; | |
821 | ||
822 | debug3("%s: entering fd = %d config len %d", __func__, fd, | |
823 | buffer_len(conf)); | |
824 | ||
825 | /* | |
826 | * Protocol from reexec master to child: | |
827 | * string configuration | |
828 | * u_int ephemeral_key_follows | |
829 | * bignum e (only if ephemeral_key_follows == 1) | |
830 | * bignum n " | |
831 | * bignum d " | |
832 | * bignum iqmp " | |
833 | * bignum p " | |
834 | * bignum q " | |
72f02ae7 | 835 | * string rngseed (only if OpenSSL is not self-seeded) |
b9a549d7 | 836 | */ |
837 | buffer_init(&m); | |
838 | buffer_put_cstring(&m, buffer_ptr(conf)); | |
839 | ||
f2107e97 | 840 | if (sensitive_data.server_key != NULL && |
b9a549d7 | 841 | sensitive_data.server_key->type == KEY_RSA1) { |
842 | buffer_put_int(&m, 1); | |
843 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->e); | |
844 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->n); | |
845 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->d); | |
846 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->iqmp); | |
847 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->p); | |
848 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->q); | |
849 | } else | |
850 | buffer_put_int(&m, 0); | |
851 | ||
72f02ae7 | 852 | #ifndef OPENSSL_PRNG_ONLY |
853 | rexec_send_rng_seed(&m); | |
854 | #endif | |
855 | ||
b9a549d7 | 856 | if (ssh_msg_send(fd, 0, &m) == -1) |
857 | fatal("%s: ssh_msg_send failed", __func__); | |
858 | ||
859 | buffer_free(&m); | |
860 | ||
861 | debug3("%s: done", __func__); | |
862 | } | |
863 | ||
864 | static void | |
865 | recv_rexec_state(int fd, Buffer *conf) | |
866 | { | |
867 | Buffer m; | |
868 | char *cp; | |
869 | u_int len; | |
870 | ||
871 | debug3("%s: entering fd = %d", __func__, fd); | |
872 | ||
873 | buffer_init(&m); | |
874 | ||
875 | if (ssh_msg_recv(fd, &m) == -1) | |
876 | fatal("%s: ssh_msg_recv failed", __func__); | |
877 | if (buffer_get_char(&m) != 0) | |
878 | fatal("%s: rexec version mismatch", __func__); | |
879 | ||
880 | cp = buffer_get_string(&m, &len); | |
881 | if (conf != NULL) | |
882 | buffer_append(conf, cp, len + 1); | |
883 | xfree(cp); | |
884 | ||
885 | if (buffer_get_int(&m)) { | |
886 | if (sensitive_data.server_key != NULL) | |
887 | key_free(sensitive_data.server_key); | |
888 | sensitive_data.server_key = key_new_private(KEY_RSA1); | |
889 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->e); | |
890 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->n); | |
891 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->d); | |
892 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->iqmp); | |
893 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->p); | |
894 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->q); | |
895 | rsa_generate_additional_parameters( | |
896 | sensitive_data.server_key->rsa); | |
897 | } | |
72f02ae7 | 898 | |
899 | #ifndef OPENSSL_PRNG_ONLY | |
900 | rexec_recv_rng_seed(&m); | |
901 | #endif | |
902 | ||
b9a549d7 | 903 | buffer_free(&m); |
904 | ||
905 | debug3("%s: done", __func__); | |
906 | } | |
907 | ||
e07335e2 | 908 | /* Accept a connection from inetd */ |
909 | static void | |
910 | server_accept_inetd(int *sock_in, int *sock_out) | |
911 | { | |
912 | int fd; | |
913 | ||
914 | startup_pipe = -1; | |
915 | if (rexeced_flag) { | |
916 | close(REEXEC_CONFIG_PASS_FD); | |
917 | *sock_in = *sock_out = dup(STDIN_FILENO); | |
918 | if (!debug_flag) { | |
919 | startup_pipe = dup(REEXEC_STARTUP_PIPE_FD); | |
920 | close(REEXEC_STARTUP_PIPE_FD); | |
921 | } | |
922 | } else { | |
923 | *sock_in = dup(STDIN_FILENO); | |
924 | *sock_out = dup(STDOUT_FILENO); | |
925 | } | |
926 | /* | |
927 | * We intentionally do not close the descriptors 0, 1, and 2 | |
928 | * as our code for setting the descriptors won't work if | |
929 | * ttyfd happens to be one of those. | |
930 | */ | |
931 | if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { | |
932 | dup2(fd, STDIN_FILENO); | |
933 | dup2(fd, STDOUT_FILENO); | |
934 | if (fd > STDOUT_FILENO) | |
935 | close(fd); | |
936 | } | |
937 | debug("inetd sockets after dupping: %d, %d", *sock_in, *sock_out); | |
938 | } | |
939 | ||
940 | /* | |
941 | * Listen for TCP connections | |
942 | */ | |
943 | static void | |
944 | server_listen(void) | |
945 | { | |
946 | int ret, listen_sock, on = 1; | |
947 | struct addrinfo *ai; | |
948 | char ntop[NI_MAXHOST], strport[NI_MAXSERV]; | |
949 | ||
950 | for (ai = options.listen_addrs; ai; ai = ai->ai_next) { | |
951 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) | |
952 | continue; | |
953 | if (num_listen_socks >= MAX_LISTEN_SOCKS) | |
954 | fatal("Too many listen sockets. " | |
955 | "Enlarge MAX_LISTEN_SOCKS"); | |
956 | if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen, | |
957 | ntop, sizeof(ntop), strport, sizeof(strport), | |
958 | NI_NUMERICHOST|NI_NUMERICSERV)) != 0) { | |
959 | error("getnameinfo failed: %.100s", | |
bb4626fe | 960 | ssh_gai_strerror(ret)); |
e07335e2 | 961 | continue; |
962 | } | |
963 | /* Create socket for listening. */ | |
16d64584 | 964 | listen_sock = socket(ai->ai_family, ai->ai_socktype, |
965 | ai->ai_protocol); | |
e07335e2 | 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 | ||
8eff0d0a | 983 | /* Only communicate in IPv6 over AF_INET6 sockets. */ |
4e1082aa | 984 | if (ai->ai_family == AF_INET6) |
985 | sock_set_v6only(listen_sock); | |
8eff0d0a | 986 | |
e07335e2 | 987 | debug("Bind to port %s on %s.", strport, ntop); |
988 | ||
989 | /* Bind the socket to the desired port. */ | |
990 | if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) { | |
991 | error("Bind to port %s on %s failed: %.200s.", | |
992 | strport, ntop, strerror(errno)); | |
993 | close(listen_sock); | |
994 | continue; | |
995 | } | |
996 | listen_socks[num_listen_socks] = listen_sock; | |
997 | num_listen_socks++; | |
998 | ||
999 | /* Start listening on the port. */ | |
1000 | if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0) | |
1001 | fatal("listen on [%s]:%s: %.100s", | |
1002 | ntop, strport, strerror(errno)); | |
1003 | logit("Server listening on %s port %s.", ntop, strport); | |
1004 | } | |
1005 | freeaddrinfo(options.listen_addrs); | |
1006 | ||
1007 | if (!num_listen_socks) | |
1008 | fatal("Cannot bind any address."); | |
1009 | } | |
1010 | ||
1011 | /* | |
1012 | * The main TCP accept loop. Note that, for the non-debug case, returns | |
1013 | * from this function are in a forked subprocess. | |
1014 | */ | |
1015 | static void | |
1016 | server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s) | |
1017 | { | |
1018 | fd_set *fdset; | |
1019 | int i, j, ret, maxfd; | |
1020 | int key_used = 0, startups = 0; | |
1021 | int startup_p[2] = { -1 , -1 }; | |
1022 | struct sockaddr_storage from; | |
1023 | socklen_t fromlen; | |
1024 | pid_t pid; | |
1025 | ||
1026 | /* setup fd set for accept */ | |
1027 | fdset = NULL; | |
1028 | maxfd = 0; | |
1029 | for (i = 0; i < num_listen_socks; i++) | |
1030 | if (listen_socks[i] > maxfd) | |
1031 | maxfd = listen_socks[i]; | |
1032 | /* pipes connected to unauthenticated childs */ | |
1033 | startup_pipes = xcalloc(options.max_startups, sizeof(int)); | |
1034 | for (i = 0; i < options.max_startups; i++) | |
1035 | startup_pipes[i] = -1; | |
1036 | ||
1037 | /* | |
1038 | * Stay listening for connections until the system crashes or | |
1039 | * the daemon is killed with a signal. | |
1040 | */ | |
1041 | for (;;) { | |
1042 | if (received_sighup) | |
1043 | sighup_restart(); | |
1044 | if (fdset != NULL) | |
1045 | xfree(fdset); | |
1046 | fdset = (fd_set *)xcalloc(howmany(maxfd + 1, NFDBITS), | |
1047 | sizeof(fd_mask)); | |
1048 | ||
1049 | for (i = 0; i < num_listen_socks; i++) | |
1050 | FD_SET(listen_socks[i], fdset); | |
1051 | for (i = 0; i < options.max_startups; i++) | |
1052 | if (startup_pipes[i] != -1) | |
1053 | FD_SET(startup_pipes[i], fdset); | |
1054 | ||
1055 | /* Wait in select until there is a connection. */ | |
1056 | ret = select(maxfd+1, fdset, NULL, NULL, NULL); | |
1057 | if (ret < 0 && errno != EINTR) | |
1058 | error("select: %.100s", strerror(errno)); | |
1059 | if (received_sigterm) { | |
1060 | logit("Received signal %d; terminating.", | |
1061 | (int) received_sigterm); | |
1062 | close_listen_socks(); | |
1063 | unlink(options.pid_file); | |
1064 | exit(255); | |
1065 | } | |
1066 | if (key_used && key_do_regen) { | |
1067 | generate_ephemeral_server_key(); | |
1068 | key_used = 0; | |
1069 | key_do_regen = 0; | |
1070 | } | |
1071 | if (ret < 0) | |
1072 | continue; | |
1073 | ||
1074 | for (i = 0; i < options.max_startups; i++) | |
1075 | if (startup_pipes[i] != -1 && | |
1076 | FD_ISSET(startup_pipes[i], fdset)) { | |
1077 | /* | |
1078 | * the read end of the pipe is ready | |
1079 | * if the child has closed the pipe | |
1080 | * after successful authentication | |
1081 | * or if the child has died | |
1082 | */ | |
1083 | close(startup_pipes[i]); | |
1084 | startup_pipes[i] = -1; | |
1085 | startups--; | |
1086 | } | |
1087 | for (i = 0; i < num_listen_socks; i++) { | |
1088 | if (!FD_ISSET(listen_socks[i], fdset)) | |
1089 | continue; | |
1090 | fromlen = sizeof(from); | |
1091 | *newsock = accept(listen_socks[i], | |
1092 | (struct sockaddr *)&from, &fromlen); | |
1093 | if (*newsock < 0) { | |
5a0c8771 | 1094 | if (errno != EINTR && errno != EAGAIN && |
1095 | errno != EWOULDBLOCK) | |
e07335e2 | 1096 | error("accept: %.100s", strerror(errno)); |
1097 | continue; | |
1098 | } | |
1099 | if (unset_nonblock(*newsock) == -1) { | |
1100 | close(*newsock); | |
1101 | continue; | |
1102 | } | |
1103 | if (drop_connection(startups) == 1) { | |
1104 | debug("drop connection #%d", startups); | |
1105 | close(*newsock); | |
1106 | continue; | |
1107 | } | |
1108 | if (pipe(startup_p) == -1) { | |
1109 | close(*newsock); | |
1110 | continue; | |
1111 | } | |
1112 | ||
1113 | if (rexec_flag && socketpair(AF_UNIX, | |
1114 | SOCK_STREAM, 0, config_s) == -1) { | |
1115 | error("reexec socketpair: %s", | |
1116 | strerror(errno)); | |
1117 | close(*newsock); | |
1118 | close(startup_p[0]); | |
1119 | close(startup_p[1]); | |
1120 | continue; | |
1121 | } | |
1122 | ||
1123 | for (j = 0; j < options.max_startups; j++) | |
1124 | if (startup_pipes[j] == -1) { | |
1125 | startup_pipes[j] = startup_p[0]; | |
1126 | if (maxfd < startup_p[0]) | |
1127 | maxfd = startup_p[0]; | |
1128 | startups++; | |
1129 | break; | |
1130 | } | |
1131 | ||
1132 | /* | |
1133 | * Got connection. Fork a child to handle it, unless | |
1134 | * we are in debugging mode. | |
1135 | */ | |
1136 | if (debug_flag) { | |
1137 | /* | |
1138 | * In debugging mode. Close the listening | |
1139 | * socket, and start processing the | |
1140 | * connection without forking. | |
1141 | */ | |
1142 | debug("Server will not fork when running in debugging mode."); | |
1143 | close_listen_socks(); | |
1144 | *sock_in = *newsock; | |
1145 | *sock_out = *newsock; | |
1146 | close(startup_p[0]); | |
1147 | close(startup_p[1]); | |
1148 | startup_pipe = -1; | |
1149 | pid = getpid(); | |
1150 | if (rexec_flag) { | |
1151 | send_rexec_state(config_s[0], | |
1152 | &cfg); | |
1153 | close(config_s[0]); | |
1154 | } | |
1155 | break; | |
1156 | } | |
1157 | ||
1158 | /* | |
1159 | * Normal production daemon. Fork, and have | |
1160 | * the child process the connection. The | |
1161 | * parent continues listening. | |
1162 | */ | |
5b84789f | 1163 | platform_pre_fork(); |
e07335e2 | 1164 | if ((pid = fork()) == 0) { |
1165 | /* | |
1166 | * Child. Close the listening and | |
1167 | * max_startup sockets. Start using | |
1168 | * the accepted socket. Reinitialize | |
1169 | * logging (since our pid has changed). | |
1170 | * We break out of the loop to handle | |
1171 | * the connection. | |
1172 | */ | |
5b84789f | 1173 | platform_post_fork_child(); |
e07335e2 | 1174 | startup_pipe = startup_p[1]; |
1175 | close_startup_pipes(); | |
1176 | close_listen_socks(); | |
1177 | *sock_in = *newsock; | |
1178 | *sock_out = *newsock; | |
1179 | log_init(__progname, | |
1180 | options.log_level, | |
1181 | options.log_facility, | |
1182 | log_stderr); | |
1183 | if (rexec_flag) | |
1184 | close(config_s[0]); | |
1185 | break; | |
1186 | } | |
1187 | ||
1188 | /* Parent. Stay in the loop. */ | |
5b84789f | 1189 | platform_post_fork_parent(pid); |
e07335e2 | 1190 | if (pid < 0) |
1191 | error("fork: %.100s", strerror(errno)); | |
1192 | else | |
1193 | debug("Forked child %ld.", (long)pid); | |
1194 | ||
1195 | close(startup_p[1]); | |
1196 | ||
1197 | if (rexec_flag) { | |
1198 | send_rexec_state(config_s[0], &cfg); | |
1199 | close(config_s[0]); | |
1200 | close(config_s[1]); | |
1201 | } | |
1202 | ||
1203 | /* | |
1204 | * Mark that the key has been used (it | |
1205 | * was "given" to the child). | |
1206 | */ | |
1207 | if ((options.protocol & SSH_PROTO_1) && | |
1208 | key_used == 0) { | |
1209 | /* Schedule server key regeneration alarm. */ | |
1210 | signal(SIGALRM, key_regeneration_alarm); | |
1211 | alarm(options.key_regeneration_time); | |
1212 | key_used = 1; | |
1213 | } | |
1214 | ||
1215 | close(*newsock); | |
1216 | ||
1217 | /* | |
1218 | * Ensure that our random state differs | |
1219 | * from that of the child | |
1220 | */ | |
1221 | arc4random_stir(); | |
1222 | } | |
1223 | ||
1224 | /* child process check (or debug mode) */ | |
1225 | if (num_listen_socks < 0) | |
1226 | break; | |
1227 | } | |
1228 | } | |
1229 | ||
1230 | ||
5260325f | 1231 | /* |
1232 | * Main program for the daemon. | |
1233 | */ | |
8efc0c15 | 1234 | int |
1235 | main(int ac, char **av) | |
1236 | { | |
5260325f | 1237 | extern char *optarg; |
1238 | extern int optind; | |
e07335e2 | 1239 | int opt, i, on = 1; |
83529a6b | 1240 | int sock_in = -1, sock_out = -1, newsock = -1; |
5260325f | 1241 | const char *remote_ip; |
1760c982 | 1242 | char *test_user = NULL, *test_host = NULL, *test_addr = NULL; |
5260325f | 1243 | int remote_port; |
1760c982 | 1244 | char *line, *p, *cp; |
e07335e2 | 1245 | int config_s[2] = { -1 , -1 }; |
e8e08a80 | 1246 | u_int64_t ibytes, obytes; |
26512357 | 1247 | mode_t new_umask; |
aeaa3d9e | 1248 | Key *key; |
2362db19 | 1249 | Authctxt *authctxt; |
5260325f | 1250 | |
6e879cb4 | 1251 | #ifdef HAVE_SECUREWARE |
1252 | (void)set_auth_parameters(ac, av); | |
1253 | #endif | |
fda04d7d | 1254 | __progname = ssh_get_progname(av[0]); |
264dce47 | 1255 | init_rng(); |
1256 | ||
d0104542 | 1257 | /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */ |
4d33e531 | 1258 | saved_argc = ac; |
7706b4c7 | 1259 | rexec_argc = ac; |
01d35895 | 1260 | saved_argv = xcalloc(ac + 1, sizeof(*saved_argv)); |
d0104542 | 1261 | for (i = 0; i < ac; i++) |
1262 | saved_argv[i] = xstrdup(av[i]); | |
f420d2ba | 1263 | saved_argv[i] = NULL; |
d0104542 | 1264 | |
1265 | #ifndef HAVE_SETPROCTITLE | |
1266 | /* Prepare for later setproctitle emulation */ | |
1267 | compat_init_setproctitle(ac, av); | |
416c732d | 1268 | av = saved_argv; |
d0104542 | 1269 | #endif |
5260325f | 1270 | |
a4c0faa2 | 1271 | if (geteuid() == 0 && setgroups(0, NULL) == -1) |
1272 | debug("setgroups(): %.200s", strerror(errno)); | |
1273 | ||
fd6168c1 | 1274 | /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ |
1275 | sanitise_stdfd(); | |
1276 | ||
5260325f | 1277 | /* Initialize configuration options to their default values. */ |
1278 | initialize_server_options(&options); | |
1279 | ||
1280 | /* Parse command-line arguments. */ | |
1760c982 | 1281 | while ((opt = getopt(ac, av, "f:p:b:k:h:g:u:o:C:dDeiqrtQRT46")) != -1) { |
5260325f | 1282 | switch (opt) { |
48e671d5 | 1283 | case '4': |
31b41ceb | 1284 | options.address_family = AF_INET; |
48e671d5 | 1285 | break; |
1286 | case '6': | |
31b41ceb | 1287 | options.address_family = AF_INET6; |
48e671d5 | 1288 | break; |
5260325f | 1289 | case 'f': |
1290 | config_file_name = optarg; | |
1291 | break; | |
1292 | case 'd': | |
e053cd2c | 1293 | if (debug_flag == 0) { |
bcbf86ec | 1294 | debug_flag = 1; |
1295 | options.log_level = SYSLOG_LEVEL_DEBUG1; | |
e053cd2c | 1296 | } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) |
bcbf86ec | 1297 | options.log_level++; |
5260325f | 1298 | break; |
0b6fbf03 | 1299 | case 'D': |
1300 | no_daemon_flag = 1; | |
1301 | break; | |
ff14faf1 | 1302 | case 'e': |
1303 | log_stderr = 1; | |
1304 | break; | |
5260325f | 1305 | case 'i': |
1306 | inetd_flag = 1; | |
1307 | break; | |
b9a549d7 | 1308 | case 'r': |
1309 | rexec_flag = 0; | |
1310 | break; | |
1311 | case 'R': | |
1312 | rexeced_flag = 1; | |
1313 | inetd_flag = 1; | |
1314 | break; | |
5260325f | 1315 | case 'Q': |
9bd5b720 | 1316 | /* ignored */ |
5260325f | 1317 | break; |
1318 | case 'q': | |
1319 | options.log_level = SYSLOG_LEVEL_QUIET; | |
1320 | break; | |
1321 | case 'b': | |
3efa8ea9 | 1322 | options.server_key_bits = (int)strtonum(optarg, 256, |
1323 | 32768, NULL); | |
5260325f | 1324 | break; |
1325 | case 'p': | |
48e671d5 | 1326 | options.ports_from_cmdline = 1; |
bcbf86ec | 1327 | if (options.num_ports >= MAX_PORTS) { |
1328 | fprintf(stderr, "too many ports.\n"); | |
1329 | exit(1); | |
1330 | } | |
2d2a2c65 | 1331 | options.ports[options.num_ports++] = a2port(optarg); |
5134115d | 1332 | if (options.ports[options.num_ports-1] <= 0) { |
2d2a2c65 | 1333 | fprintf(stderr, "Bad port number.\n"); |
1334 | exit(1); | |
1335 | } | |
5260325f | 1336 | break; |
1337 | case 'g': | |
e2b1fb42 | 1338 | if ((options.login_grace_time = convtime(optarg)) == -1) { |
1339 | fprintf(stderr, "Invalid login grace time.\n"); | |
1340 | exit(1); | |
1341 | } | |
5260325f | 1342 | break; |
1343 | case 'k': | |
e2b1fb42 | 1344 | if ((options.key_regeneration_time = convtime(optarg)) == -1) { |
1345 | fprintf(stderr, "Invalid key regeneration interval.\n"); | |
1346 | exit(1); | |
1347 | } | |
5260325f | 1348 | break; |
1349 | case 'h': | |
fa08c86b | 1350 | if (options.num_host_key_files >= MAX_HOSTKEYS) { |
1351 | fprintf(stderr, "too many host keys.\n"); | |
1352 | exit(1); | |
1353 | } | |
ca24b550 | 1354 | options.host_key_files[options.num_host_key_files++] = |
1355 | derelativise_path(optarg); | |
5260325f | 1356 | break; |
f87f09aa | 1357 | case 't': |
1358 | test_flag = 1; | |
1359 | break; | |
1760c982 | 1360 | case 'T': |
1361 | test_flag = 2; | |
1362 | break; | |
1363 | case 'C': | |
1364 | cp = optarg; | |
1365 | while ((p = strsep(&cp, ",")) && *p != '\0') { | |
1366 | if (strncmp(p, "addr=", 5) == 0) | |
1367 | test_addr = xstrdup(p + 5); | |
1368 | else if (strncmp(p, "host=", 5) == 0) | |
1369 | test_host = xstrdup(p + 5); | |
1370 | else if (strncmp(p, "user=", 5) == 0) | |
1371 | test_user = xstrdup(p + 5); | |
1372 | else { | |
1373 | fprintf(stderr, "Invalid test " | |
1374 | "mode specification %s\n", p); | |
1375 | exit(1); | |
1376 | } | |
1377 | } | |
1378 | break; | |
c345cf9d | 1379 | case 'u': |
3efa8ea9 | 1380 | utmp_len = (u_int)strtonum(optarg, 0, MAXHOSTNAMELEN+1, NULL); |
67f04db1 | 1381 | if (utmp_len > MAXHOSTNAMELEN) { |
1382 | fprintf(stderr, "Invalid utmp length.\n"); | |
1383 | exit(1); | |
1384 | } | |
c345cf9d | 1385 | break; |
2717fa0f | 1386 | case 'o': |
c5894280 | 1387 | line = xstrdup(optarg); |
1388 | if (process_server_config_line(&options, line, | |
d231781a | 1389 | "command-line", 0, NULL, NULL, NULL, NULL) != 0) |
184eed6a | 1390 | exit(1); |
c5894280 | 1391 | xfree(line); |
2717fa0f | 1392 | break; |
5260325f | 1393 | case '?': |
1394 | default: | |
2717fa0f | 1395 | usage(); |
1396 | break; | |
5260325f | 1397 | } |
1398 | } | |
b9a549d7 | 1399 | if (rexeced_flag || inetd_flag) |
1400 | rexec_flag = 0; | |
2600996b | 1401 | if (!test_flag && (rexec_flag && (av[0] == NULL || *av[0] != '/'))) |
b9a549d7 | 1402 | fatal("sshd re-exec requires execution with an absolute path"); |
1403 | if (rexeced_flag) | |
b250e837 | 1404 | closefrom(REEXEC_MIN_FREE_FD); |
1405 | else | |
1406 | closefrom(REEXEC_DEVCRYPTO_RESERVED_FD); | |
b9a549d7 | 1407 | |
1a92bd7e | 1408 | SSLeay_add_all_algorithms(); |
5260325f | 1409 | |
48e671d5 | 1410 | /* |
1411 | * Force logging to stderr until we have loaded the private host | |
1412 | * key (unless started from inetd) | |
1413 | */ | |
1fe6a48f | 1414 | log_init(__progname, |
980c9344 | 1415 | options.log_level == SYSLOG_LEVEL_NOT_SET ? |
1416 | SYSLOG_LEVEL_INFO : options.log_level, | |
1417 | options.log_facility == SYSLOG_FACILITY_NOT_SET ? | |
1418 | SYSLOG_FACILITY_AUTH : options.log_facility, | |
51efad8c | 1419 | log_stderr || !inetd_flag); |
48e671d5 | 1420 | |
351f44a0 | 1421 | /* |
1422 | * Unset KRB5CCNAME, otherwise the user's session may inherit it from | |
1423 | * root's environment | |
d1cf9a87 | 1424 | */ |
3bfd27d5 | 1425 | if (getenv("KRB5CCNAME") != NULL) |
1426 | unsetenv("KRB5CCNAME"); | |
1427 | ||
ef51930f | 1428 | #ifdef _UNICOS |
e5ba4718 | 1429 | /* Cray can define user privs drop all privs now! |
1a23ac2c | 1430 | * Not needed on PRIV_SU systems! |
1431 | */ | |
1432 | drop_cray_privs(); | |
1433 | #endif | |
1434 | ||
b9a549d7 | 1435 | sensitive_data.server_key = NULL; |
1436 | sensitive_data.ssh1_host_key = NULL; | |
1437 | sensitive_data.have_ssh1_key = 0; | |
1438 | sensitive_data.have_ssh2_key = 0; | |
1439 | ||
1760c982 | 1440 | /* |
1441 | * If we're doing an extended config test, make sure we have all of | |
1442 | * the parameters we need. If we're not doing an extended test, | |
1443 | * do not silently ignore connection test params. | |
1444 | */ | |
081573fe | 1445 | if (test_flag >= 2 && |
1446 | (test_user != NULL || test_host != NULL || test_addr != NULL) | |
1760c982 | 1447 | && (test_user == NULL || test_host == NULL || test_addr == NULL)) |
1448 | fatal("user, host and addr are all required when testing " | |
1449 | "Match configs"); | |
1450 | if (test_flag < 2 && (test_user != NULL || test_host != NULL || | |
1451 | test_addr != NULL)) | |
1452 | fatal("Config test connection parameter (-C) provided without " | |
1453 | "test mode (-T)"); | |
1454 | ||
b9a549d7 | 1455 | /* Fetch our configuration */ |
1456 | buffer_init(&cfg); | |
1457 | if (rexeced_flag) | |
b250e837 | 1458 | recv_rexec_state(REEXEC_CONFIG_PASS_FD, &cfg); |
b9a549d7 | 1459 | else |
1460 | load_server_config(config_file_name, &cfg); | |
1461 | ||
d231781a | 1462 | parse_server_config(&options, rexeced_flag ? "rexec" : config_file_name, |
1463 | &cfg, NULL, NULL, NULL); | |
5260325f | 1464 | |
72f02ae7 | 1465 | seed_rng(); |
1466 | ||
5260325f | 1467 | /* Fill in default values for those options not explicitly set. */ |
1468 | fill_default_server_options(&options); | |
1469 | ||
136d42b7 | 1470 | /* challenge-response is implemented via keyboard interactive */ |
1471 | if (options.challenge_response_authentication) | |
1472 | options.kbd_interactive_authentication = 1; | |
1473 | ||
16d64584 | 1474 | /* set default channel AF */ |
31b41ceb | 1475 | channel_set_af(options.address_family); |
1476 | ||
5260325f | 1477 | /* Check that there are no remaining arguments. */ |
1478 | if (optind < ac) { | |
1479 | fprintf(stderr, "Extra argument %s.\n", av[optind]); | |
1480 | exit(1); | |
8efc0c15 | 1481 | } |
5260325f | 1482 | |
4526e8c2 | 1483 | debug("sshd version %.100s", SSH_RELEASE); |
5260325f | 1484 | |
4d02b823 | 1485 | /* Store privilege separation user for later use if required. */ |
1486 | if ((privsep_pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) { | |
1487 | if (use_privsep || options.kerberos_authentication) | |
1488 | fatal("Privilege separation user %s does not exist", | |
1489 | SSH_PRIVSEP_USER); | |
1490 | } else { | |
1491 | memset(privsep_pw->pw_passwd, 0, strlen(privsep_pw->pw_passwd)); | |
1492 | privsep_pw = pwcopy(privsep_pw); | |
1493 | xfree(privsep_pw->pw_passwd); | |
1494 | privsep_pw->pw_passwd = xstrdup("*"); | |
1495 | } | |
a078cbee | 1496 | endpwent(); |
1497 | ||
fa08c86b | 1498 | /* load private host keys */ |
52e3daed | 1499 | sensitive_data.host_keys = xcalloc(options.num_host_key_files, |
343288b8 | 1500 | sizeof(Key *)); |
184eed6a | 1501 | for (i = 0; i < options.num_host_key_files; i++) |
1e3b8b07 | 1502 | sensitive_data.host_keys[i] = NULL; |
a306f2dd | 1503 | |
184eed6a | 1504 | for (i = 0; i < options.num_host_key_files; i++) { |
aeaa3d9e | 1505 | key = key_load_private(options.host_key_files[i], "", NULL); |
1506 | sensitive_data.host_keys[i] = key; | |
fa08c86b | 1507 | if (key == NULL) { |
58cfa257 | 1508 | error("Could not load host key: %s", |
1509 | options.host_key_files[i]); | |
aeaa3d9e | 1510 | sensitive_data.host_keys[i] = NULL; |
fa08c86b | 1511 | continue; |
a306f2dd | 1512 | } |
6aacefa7 | 1513 | switch (key->type) { |
fa08c86b | 1514 | case KEY_RSA1: |
1515 | sensitive_data.ssh1_host_key = key; | |
1516 | sensitive_data.have_ssh1_key = 1; | |
1517 | break; | |
1518 | case KEY_RSA: | |
1519 | case KEY_DSA: | |
1520 | sensitive_data.have_ssh2_key = 1; | |
1521 | break; | |
a306f2dd | 1522 | } |
aeaa3d9e | 1523 | debug("private host key: #%d type %d %s", i, key->type, |
1524 | key_type(key)); | |
fa08c86b | 1525 | } |
1526 | if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) { | |
bbe88b6d | 1527 | logit("Disabling protocol version 1. Could not load host key"); |
fa08c86b | 1528 | options.protocol &= ~SSH_PROTO_1; |
1529 | } | |
1530 | if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) { | |
bbe88b6d | 1531 | logit("Disabling protocol version 2. Could not load host key"); |
fa08c86b | 1532 | options.protocol &= ~SSH_PROTO_2; |
a306f2dd | 1533 | } |
6a416424 | 1534 | if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) { |
bbe88b6d | 1535 | logit("sshd: no hostkeys available -- exiting."); |
5260325f | 1536 | exit(1); |
1537 | } | |
5260325f | 1538 | |
a306f2dd | 1539 | /* Check certain values for sanity. */ |
1540 | if (options.protocol & SSH_PROTO_1) { | |
1541 | if (options.server_key_bits < 512 || | |
1542 | options.server_key_bits > 32768) { | |
1543 | fprintf(stderr, "Bad server key size.\n"); | |
1544 | exit(1); | |
1545 | } | |
1546 | /* | |
1547 | * Check that server and host key lengths differ sufficiently. This | |
1548 | * is necessary to make double encryption work with rsaref. Oh, I | |
1549 | * hate software patents. I dont know if this can go? Niels | |
1550 | */ | |
1551 | if (options.server_key_bits > | |
e424e241 | 1552 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) - |
1553 | SSH_KEY_BITS_RESERVED && options.server_key_bits < | |
1554 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + | |
1555 | SSH_KEY_BITS_RESERVED) { | |
a306f2dd | 1556 | options.server_key_bits = |
e424e241 | 1557 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + |
1558 | SSH_KEY_BITS_RESERVED; | |
a306f2dd | 1559 | debug("Forcing server key to %d bits to make it differ from host key.", |
1560 | options.server_key_bits); | |
1561 | } | |
1562 | } | |
1563 | ||
3cc54fbb | 1564 | if (use_privsep) { |
3cc54fbb | 1565 | struct stat st; |
1566 | ||
3cc54fbb | 1567 | if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) || |
1568 | (S_ISDIR(st.st_mode) == 0)) | |
1569 | fatal("Missing privilege separation directory: %s", | |
1570 | _PATH_PRIVSEP_CHROOT_DIR); | |
b9b82dab | 1571 | |
1572 | #ifdef HAVE_CYGWIN | |
1573 | if (check_ntsec(_PATH_PRIVSEP_CHROOT_DIR) && | |
1574 | (st.st_uid != getuid () || | |
1575 | (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)) | |
1576 | #else | |
a56313d7 | 1577 | if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0) |
b9b82dab | 1578 | #endif |
5f021474 | 1579 | fatal("%s must be owned by root and not group or " |
1580 | "world-writable.", _PATH_PRIVSEP_CHROOT_DIR); | |
3cc54fbb | 1581 | } |
1582 | ||
1760c982 | 1583 | if (test_flag > 1) { |
1584 | if (test_user != NULL && test_addr != NULL && test_host != NULL) | |
1585 | parse_server_match_config(&options, test_user, | |
1586 | test_host, test_addr); | |
1587 | dump_config(&options); | |
1588 | } | |
1589 | ||
f87f09aa | 1590 | /* Configuration looks good, so exit if in test mode. */ |
1591 | if (test_flag) | |
1592 | exit(0); | |
1593 | ||
018a5ea3 | 1594 | /* |
1595 | * Clear out any supplemental groups we may have inherited. This | |
1596 | * prevents inadvertent creation of files with bad modes (in the | |
aff51935 | 1597 | * portable version at least, it's certainly possible for PAM |
1598 | * to create a file, and we can't control the code in every | |
018a5ea3 | 1599 | * module which might be used). |
1600 | */ | |
1601 | if (setgroups(0, NULL) < 0) | |
1602 | debug("setgroups() failed: %.200s", strerror(errno)); | |
1603 | ||
b9a549d7 | 1604 | if (rexec_flag) { |
52e3daed | 1605 | rexec_argv = xcalloc(rexec_argc + 2, sizeof(char *)); |
b9a549d7 | 1606 | for (i = 0; i < rexec_argc; i++) { |
1607 | debug("rexec_argv[%d]='%s'", i, saved_argv[i]); | |
1608 | rexec_argv[i] = saved_argv[i]; | |
1609 | } | |
1610 | rexec_argv[rexec_argc] = "-R"; | |
1611 | rexec_argv[rexec_argc + 1] = NULL; | |
1612 | } | |
1613 | ||
26512357 | 1614 | /* Ensure that umask disallows at least group and world write */ |
1615 | new_umask = umask(0077) | 0022; | |
1616 | (void) umask(new_umask); | |
1617 | ||
a306f2dd | 1618 | /* Initialize the log (it is reinitialized below in case we forked). */ |
25c31d49 | 1619 | if (debug_flag && (!inetd_flag || rexeced_flag)) |
5260325f | 1620 | log_stderr = 1; |
1fe6a48f | 1621 | log_init(__progname, options.log_level, options.log_facility, log_stderr); |
5260325f | 1622 | |
a306f2dd | 1623 | /* |
1624 | * If not in debugging mode, and not started from inetd, disconnect | |
1625 | * from the controlling terminal, and fork. The original process | |
1626 | * exits. | |
1627 | */ | |
0b6fbf03 | 1628 | if (!(debug_flag || inetd_flag || no_daemon_flag)) { |
8efc0c15 | 1629 | #ifdef TIOCNOTTY |
5260325f | 1630 | int fd; |
8efc0c15 | 1631 | #endif /* TIOCNOTTY */ |
5260325f | 1632 | if (daemon(0, 0) < 0) |
1633 | fatal("daemon() failed: %.200s", strerror(errno)); | |
1634 | ||
1635 | /* Disconnect from the controlling tty. */ | |
8efc0c15 | 1636 | #ifdef TIOCNOTTY |
5ca51e19 | 1637 | fd = open(_PATH_TTY, O_RDWR | O_NOCTTY); |
5260325f | 1638 | if (fd >= 0) { |
1639 | (void) ioctl(fd, TIOCNOTTY, NULL); | |
1640 | close(fd); | |
1641 | } | |
8efc0c15 | 1642 | #endif /* TIOCNOTTY */ |
8efc0c15 | 1643 | } |
5260325f | 1644 | /* Reinitialize the log (because of the fork above). */ |
1fe6a48f | 1645 | log_init(__progname, options.log_level, options.log_facility, log_stderr); |
5260325f | 1646 | |
5260325f | 1647 | /* Initialize the random number generator. */ |
1648 | arc4random_stir(); | |
1649 | ||
1650 | /* Chdir to the root directory so that the current disk can be | |
1651 | unmounted if desired. */ | |
1652 | chdir("/"); | |
184eed6a | 1653 | |
1d3c30db | 1654 | /* ignore SIGPIPE */ |
1655 | signal(SIGPIPE, SIG_IGN); | |
5260325f | 1656 | |
e07335e2 | 1657 | /* Get a connection, either from inetd or a listening TCP socket */ |
5260325f | 1658 | if (inetd_flag) { |
e07335e2 | 1659 | server_accept_inetd(&sock_in, &sock_out); |
5260325f | 1660 | } else { |
fd2d830a | 1661 | platform_pre_listen(); |
e07335e2 | 1662 | server_listen(); |
48e671d5 | 1663 | |
3aca00a3 | 1664 | if (options.protocol & SSH_PROTO_1) |
1665 | generate_ephemeral_server_key(); | |
1666 | ||
3aca00a3 | 1667 | signal(SIGHUP, sighup_handler); |
e07335e2 | 1668 | signal(SIGCHLD, main_sigchld_handler); |
3aca00a3 | 1669 | signal(SIGTERM, sigterm_handler); |
1670 | signal(SIGQUIT, sigterm_handler); | |
1671 | ||
e07335e2 | 1672 | /* |
1673 | * Write out the pid file after the sigterm handler | |
1674 | * is setup and the listen sockets are bound | |
1675 | */ | |
5260325f | 1676 | if (!debug_flag) { |
e07335e2 | 1677 | FILE *f = fopen(options.pid_file, "w"); |
1678 | ||
71b9ced0 | 1679 | if (f == NULL) { |
1680 | error("Couldn't create pid file \"%s\": %s", | |
1681 | options.pid_file, strerror(errno)); | |
1682 | } else { | |
c457707e | 1683 | fprintf(f, "%ld\n", (long) getpid()); |
5260325f | 1684 | fclose(f); |
1685 | } | |
8efc0c15 | 1686 | } |
5260325f | 1687 | |
e07335e2 | 1688 | /* Accept a connection and return in a forked child */ |
1689 | server_accept_loop(&sock_in, &sock_out, | |
1690 | &newsock, config_s); | |
5260325f | 1691 | } |
8efc0c15 | 1692 | |
5260325f | 1693 | /* This is the child processing a new connection. */ |
cc120685 | 1694 | setproctitle("%s", "[accepted]"); |
5260325f | 1695 | |
8b758bd2 | 1696 | /* |
1697 | * Create a new session and process group since the 4.4BSD | |
1698 | * setlogin() affects the entire process group. We don't | |
1699 | * want the child to be able to affect the parent. | |
1700 | */ | |
1701 | #if !defined(SSHD_ACQUIRES_CTTY) | |
1702 | /* | |
1703 | * If setsid is called, on some platforms sshd will later acquire a | |
1704 | * controlling terminal which will result in "could not set | |
1705 | * controlling tty" errors. | |
1706 | */ | |
1707 | if (!debug_flag && !inetd_flag && setsid() < 0) | |
1708 | error("setsid: %.100s", strerror(errno)); | |
1709 | #endif | |
1710 | ||
b9a549d7 | 1711 | if (rexec_flag) { |
1712 | int fd; | |
1713 | ||
b250e837 | 1714 | debug("rexec start in %d out %d newsock %d pipe %d sock %d", |
1715 | sock_in, sock_out, newsock, startup_pipe, config_s[0]); | |
b9a549d7 | 1716 | dup2(newsock, STDIN_FILENO); |
1717 | dup2(STDIN_FILENO, STDOUT_FILENO); | |
1718 | if (startup_pipe == -1) | |
b250e837 | 1719 | close(REEXEC_STARTUP_PIPE_FD); |
b9a549d7 | 1720 | else |
b250e837 | 1721 | dup2(startup_pipe, REEXEC_STARTUP_PIPE_FD); |
b9a549d7 | 1722 | |
b250e837 | 1723 | dup2(config_s[1], REEXEC_CONFIG_PASS_FD); |
b9a549d7 | 1724 | close(config_s[1]); |
ad148c04 | 1725 | if (startup_pipe != -1) |
1726 | close(startup_pipe); | |
b250e837 | 1727 | |
b9a549d7 | 1728 | execv(rexec_argv[0], rexec_argv); |
1729 | ||
1730 | /* Reexec has failed, fall back and continue */ | |
1731 | error("rexec of %s failed: %s", rexec_argv[0], strerror(errno)); | |
b250e837 | 1732 | recv_rexec_state(REEXEC_CONFIG_PASS_FD, NULL); |
b9a549d7 | 1733 | log_init(__progname, options.log_level, |
1734 | options.log_facility, log_stderr); | |
1735 | ||
1736 | /* Clean up fds */ | |
b250e837 | 1737 | startup_pipe = REEXEC_STARTUP_PIPE_FD; |
b9a549d7 | 1738 | close(config_s[1]); |
b250e837 | 1739 | close(REEXEC_CONFIG_PASS_FD); |
1740 | newsock = sock_out = sock_in = dup(STDIN_FILENO); | |
b9a549d7 | 1741 | if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { |
1742 | dup2(fd, STDIN_FILENO); | |
1743 | dup2(fd, STDOUT_FILENO); | |
1744 | if (fd > STDERR_FILENO) | |
1745 | close(fd); | |
1746 | } | |
b250e837 | 1747 | debug("rexec cleanup in %d out %d newsock %d pipe %d sock %d", |
1748 | sock_in, sock_out, newsock, startup_pipe, config_s[0]); | |
b9a549d7 | 1749 | } |
1750 | ||
08427260 | 1751 | /* Executed child processes don't need these. */ |
1752 | fcntl(sock_out, F_SETFD, FD_CLOEXEC); | |
1753 | fcntl(sock_in, F_SETFD, FD_CLOEXEC); | |
1754 | ||
aa3378df | 1755 | /* |
1756 | * Disable the key regeneration alarm. We will not regenerate the | |
1757 | * key since we are no longer in a position to give it to anyone. We | |
1758 | * will not restart on SIGHUP since it no longer makes sense. | |
1759 | */ | |
5260325f | 1760 | alarm(0); |
1761 | signal(SIGALRM, SIG_DFL); | |
1762 | signal(SIGHUP, SIG_DFL); | |
1763 | signal(SIGTERM, SIG_DFL); | |
1764 | signal(SIGQUIT, SIG_DFL); | |
1765 | signal(SIGCHLD, SIG_DFL); | |
9aaf9be4 | 1766 | signal(SIGINT, SIG_DFL); |
5260325f | 1767 | |
aa3378df | 1768 | /* |
1769 | * Register our connection. This turns encryption off because we do | |
1770 | * not have a key. | |
1771 | */ | |
5260325f | 1772 | packet_set_connection(sock_in, sock_out); |
07200973 | 1773 | packet_set_server(); |
5260325f | 1774 | |
7c3bc5a2 | 1775 | /* Set SO_KEEPALIVE if requested. */ |
1776 | if (options.tcp_keep_alive && packet_connection_is_on_socket() && | |
1777 | setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) < 0) | |
1778 | error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); | |
1779 | ||
29798ed0 | 1780 | if ((remote_port = get_remote_port()) < 0) { |
1781 | debug("get_remote_port failed"); | |
1782 | cleanup_exit(255); | |
1783 | } | |
3a85986d | 1784 | |
1785 | /* | |
1786 | * We use get_canonical_hostname with usedns = 0 instead of | |
1787 | * get_remote_ipaddr here so IP options will be checked. | |
1788 | */ | |
211f229e | 1789 | (void) get_canonical_hostname(0); |
1790 | /* | |
1791 | * The rest of the code depends on the fact that | |
1792 | * get_remote_ipaddr() caches the remote ip, even if | |
1793 | * the socket goes away. | |
1794 | */ | |
1795 | remote_ip = get_remote_ipaddr(); | |
5260325f | 1796 | |
6039eeef | 1797 | #ifdef SSH_AUDIT_EVENTS |
c00e4d75 | 1798 | audit_connection_from(remote_ip, remote_port); |
1799 | #endif | |
5260325f | 1800 | #ifdef LIBWRAP |
5c7fd4ce | 1801 | allow_severity = options.log_facility|LOG_INFO; |
1802 | deny_severity = options.log_facility|LOG_WARNING; | |
ac28afd8 | 1803 | /* Check whether logins are denied from this host. */ |
33e5359c | 1804 | if (packet_connection_is_on_socket()) { |
5260325f | 1805 | struct request_info req; |
8efc0c15 | 1806 | |
8fbc356d | 1807 | request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0); |
5260325f | 1808 | fromhost(&req); |
8efc0c15 | 1809 | |
5260325f | 1810 | if (!hosts_access(&req)) { |
ac28afd8 | 1811 | debug("Connection refused by tcp wrapper"); |
563834bb | 1812 | refuse(&req); |
ac28afd8 | 1813 | /* NOTREACHED */ |
1814 | fatal("libwrap refuse returns"); | |
5260325f | 1815 | } |
8efc0c15 | 1816 | } |
48e671d5 | 1817 | #endif /* LIBWRAP */ |
ac28afd8 | 1818 | |
5260325f | 1819 | /* Log the connection. */ |
1820 | verbose("Connection from %.500s port %d", remote_ip, remote_port); | |
8efc0c15 | 1821 | |
aa3378df | 1822 | /* |
7b9b0103 | 1823 | * We don't want to listen forever unless the other side |
aa3378df | 1824 | * successfully authenticates itself. So we set up an alarm which is |
1825 | * cleared after successful authentication. A limit of zero | |
7b9b0103 | 1826 | * indicates no limit. Note that we don't set the alarm in debugging |
aa3378df | 1827 | * mode; it is just annoying to have the server exit just when you |
1828 | * are about to discover the bug. | |
1829 | */ | |
f00d1f78 | 1830 | signal(SIGALRM, grace_alarm_handler); |
5260325f | 1831 | if (!debug_flag) |
1832 | alarm(options.login_grace_time); | |
1833 | ||
7368a6c8 | 1834 | sshd_exchange_identification(sock_in, sock_out); |
0598d99d | 1835 | |
59d68bae | 1836 | /* In inetd mode, generate ephemeral key only for proto 1 connections */ |
1837 | if (!compat20 && inetd_flag && sensitive_data.server_key == NULL) | |
1838 | generate_ephemeral_server_key(); | |
1839 | ||
5260325f | 1840 | packet_set_nonblocking(); |
1841 | ||
2362db19 | 1842 | /* allocate authentication context */ |
52e3daed | 1843 | authctxt = xcalloc(1, sizeof(*authctxt)); |
2362db19 | 1844 | |
1b394137 | 1845 | authctxt->loginmsg = &loginmsg; |
1846 | ||
2362db19 | 1847 | /* XXX global for cleanup, access from other modules */ |
1848 | the_authctxt = authctxt; | |
1849 | ||
022487ce | 1850 | /* prepare buffer to collect messages to display to user after login */ |
1851 | buffer_init(&loginmsg); | |
1852 | ||
324bf712 | 1853 | if (use_privsep) |
2362db19 | 1854 | if (privsep_preauth(authctxt) == 1) |
324bf712 | 1855 | goto authenticated; |
1853d1ef | 1856 | |
7b2ea3a1 | 1857 | /* perform the key exchange */ |
7b2ea3a1 | 1858 | /* authenticate user and start session */ |
e78a59f5 | 1859 | if (compat20) { |
1860 | do_ssh2_kex(); | |
2362db19 | 1861 | do_authentication2(authctxt); |
e78a59f5 | 1862 | } else { |
1863 | do_ssh1_kex(); | |
2362db19 | 1864 | do_authentication(authctxt); |
e78a59f5 | 1865 | } |
324bf712 | 1866 | /* |
1867 | * If we use privilege separation, the unprivileged child transfers | |
1868 | * the current keystate and exits | |
1869 | */ | |
1870 | if (use_privsep) { | |
b5a28cbc | 1871 | mm_send_keystate(pmonitor); |
1853d1ef | 1872 | exit(0); |
324bf712 | 1873 | } |
1853d1ef | 1874 | |
1875 | authenticated: | |
678143bd | 1876 | /* |
1877 | * Cancel the alarm we set to limit the time taken for | |
1878 | * authentication. | |
1879 | */ | |
1880 | alarm(0); | |
1881 | signal(SIGALRM, SIG_DFL); | |
184cb418 | 1882 | authctxt->authenticated = 1; |
678143bd | 1883 | if (startup_pipe != -1) { |
1884 | close(startup_pipe); | |
1885 | startup_pipe = -1; | |
1886 | } | |
1887 | ||
6039eeef | 1888 | #ifdef SSH_AUDIT_EVENTS |
1889 | audit_event(SSH_AUTH_SUCCESS); | |
c00e4d75 | 1890 | #endif |
1891 | ||
83fa7e8d | 1892 | #ifdef GSSAPI |
1893 | if (options.gss_authentication) { | |
1894 | temporarily_use_uid(authctxt->pw); | |
1895 | ssh_gssapi_storecreds(); | |
1896 | restore_uid(); | |
1897 | } | |
1898 | #endif | |
1899 | #ifdef USE_PAM | |
1900 | if (options.use_pam) { | |
1901 | do_pam_setcred(1); | |
1902 | do_pam_session(); | |
1903 | } | |
1904 | #endif | |
1905 | ||
762715ce | 1906 | /* |
1853d1ef | 1907 | * In privilege separation, we fork another child and prepare |
1908 | * file descriptor passing. | |
1909 | */ | |
1910 | if (use_privsep) { | |
324bf712 | 1911 | privsep_postauth(authctxt); |
1912 | /* the monitor process [priv] will not return */ | |
1853d1ef | 1913 | if (!compat20) |
1914 | destroy_sensitive_data(); | |
1915 | } | |
1b34c1b3 | 1916 | |
bc2d97c8 | 1917 | packet_set_timeout(options.client_alive_interval, |
1918 | options.client_alive_count_max); | |
1919 | ||
2362db19 | 1920 | /* Start session. */ |
1b34c1b3 | 1921 | do_authenticated(authctxt); |
1922 | ||
63284fbb | 1923 | /* The connection has been terminated. */ |
e8e08a80 | 1924 | packet_get_state(MODE_IN, NULL, NULL, NULL, &ibytes); |
1925 | packet_get_state(MODE_OUT, NULL, NULL, NULL, &obytes); | |
1926 | verbose("Transferred: sent %llu, received %llu bytes", obytes, ibytes); | |
1927 | ||
1928 | verbose("Closing connection to %.500s port %d", remote_ip, remote_port); | |
8efc0c15 | 1929 | |
d94aa2ae | 1930 | #ifdef USE_PAM |
7fceb20d | 1931 | if (options.use_pam) |
1932 | finish_pam(); | |
d94aa2ae | 1933 | #endif /* USE_PAM */ |
8efc0c15 | 1934 | |
2b0c0925 | 1935 | #ifdef SSH_AUDIT_EVENTS |
1936 | PRIVSEP(audit_event(SSH_CONNECTION_CLOSE)); | |
1937 | #endif | |
1938 | ||
5260325f | 1939 | packet_close(); |
1853d1ef | 1940 | |
1941 | if (use_privsep) | |
1942 | mm_terminate(); | |
1943 | ||
5260325f | 1944 | exit(0); |
1945 | } | |
8efc0c15 | 1946 | |
4f08e98d | 1947 | /* |
1948 | * Decrypt session_key_int using our private server key and private host key | |
1949 | * (key with larger modulus first). | |
1950 | */ | |
1853d1ef | 1951 | int |
4f08e98d | 1952 | ssh1_session_key(BIGNUM *session_key_int) |
1953 | { | |
1954 | int rsafail = 0; | |
1955 | ||
3efa8ea9 | 1956 | if (BN_cmp(sensitive_data.server_key->rsa->n, |
1957 | sensitive_data.ssh1_host_key->rsa->n) > 0) { | |
4f08e98d | 1958 | /* Server key has bigger modulus. */ |
1959 | if (BN_num_bits(sensitive_data.server_key->rsa->n) < | |
3efa8ea9 | 1960 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + |
1961 | SSH_KEY_BITS_RESERVED) { | |
1962 | fatal("do_connection: %s: " | |
1963 | "server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d", | |
4f08e98d | 1964 | get_remote_ipaddr(), |
1965 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
1966 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), | |
1967 | SSH_KEY_BITS_RESERVED); | |
1968 | } | |
1969 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1970 | sensitive_data.server_key->rsa) <= 0) | |
1971 | rsafail++; | |
1972 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1973 | sensitive_data.ssh1_host_key->rsa) <= 0) | |
1974 | rsafail++; | |
1975 | } else { | |
1976 | /* Host key has bigger modulus (or they are equal). */ | |
1977 | if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) < | |
3efa8ea9 | 1978 | BN_num_bits(sensitive_data.server_key->rsa->n) + |
1979 | SSH_KEY_BITS_RESERVED) { | |
1980 | fatal("do_connection: %s: " | |
1981 | "host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d", | |
4f08e98d | 1982 | get_remote_ipaddr(), |
1983 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), | |
1984 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
1985 | SSH_KEY_BITS_RESERVED); | |
1986 | } | |
1987 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1988 | sensitive_data.ssh1_host_key->rsa) < 0) | |
1989 | rsafail++; | |
1990 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1991 | sensitive_data.server_key->rsa) < 0) | |
1992 | rsafail++; | |
1993 | } | |
1994 | return (rsafail); | |
1995 | } | |
5260325f | 1996 | /* |
7b2ea3a1 | 1997 | * SSH1 key exchange |
5260325f | 1998 | */ |
396c147e | 1999 | static void |
1e3b8b07 | 2000 | do_ssh1_kex(void) |
8efc0c15 | 2001 | { |
5260325f | 2002 | int i, len; |
46aa2d1f | 2003 | int rsafail = 0; |
5260325f | 2004 | BIGNUM *session_key_int; |
1e3b8b07 | 2005 | u_char session_key[SSH_SESSION_KEY_LENGTH]; |
2006 | u_char cookie[8]; | |
2007 | u_int cipher_type, auth_mask, protocol_flags; | |
5260325f | 2008 | |
aa3378df | 2009 | /* |
2010 | * Generate check bytes that the client must send back in the user | |
2011 | * packet in order for it to be accepted; this is used to defy ip | |
2012 | * spoofing attacks. Note that this only works against somebody | |
2013 | * doing IP spoofing from a remote machine; any machine on the local | |
2014 | * network can still see outgoing packets and catch the random | |
2015 | * cookie. This only affects rhosts authentication, and this is one | |
2016 | * of the reasons why it is inherently insecure. | |
2017 | */ | |
c1d152b8 | 2018 | arc4random_buf(cookie, sizeof(cookie)); |
5260325f | 2019 | |
aa3378df | 2020 | /* |
2021 | * Send our public key. We include in the packet 64 bits of random | |
2022 | * data that must be matched in the reply in order to prevent IP | |
2023 | * spoofing. | |
2024 | */ | |
5260325f | 2025 | packet_start(SSH_SMSG_PUBLIC_KEY); |
2026 | for (i = 0; i < 8; i++) | |
7b2ea3a1 | 2027 | packet_put_char(cookie[i]); |
5260325f | 2028 | |
2029 | /* Store our public server RSA key. */ | |
fa08c86b | 2030 | packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n)); |
2031 | packet_put_bignum(sensitive_data.server_key->rsa->e); | |
2032 | packet_put_bignum(sensitive_data.server_key->rsa->n); | |
5260325f | 2033 | |
2034 | /* Store our public host RSA key. */ | |
fa08c86b | 2035 | packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); |
2036 | packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e); | |
2037 | packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n); | |
5260325f | 2038 | |
2039 | /* Put protocol flags. */ | |
2040 | packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN); | |
2041 | ||
2042 | /* Declare which ciphers we support. */ | |
94ec8c6b | 2043 | packet_put_int(cipher_mask_ssh1(0)); |
5260325f | 2044 | |
2045 | /* Declare supported authentication types. */ | |
2046 | auth_mask = 0; | |
5260325f | 2047 | if (options.rhosts_rsa_authentication) |
2048 | auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA; | |
2049 | if (options.rsa_authentication) | |
2050 | auth_mask |= 1 << SSH_AUTH_RSA; | |
5ba55ada | 2051 | if (options.challenge_response_authentication == 1) |
5260325f | 2052 | auth_mask |= 1 << SSH_AUTH_TIS; |
5260325f | 2053 | if (options.password_authentication) |
2054 | auth_mask |= 1 << SSH_AUTH_PASSWORD; | |
2055 | packet_put_int(auth_mask); | |
2056 | ||
2057 | /* Send the packet and wait for it to be sent. */ | |
2058 | packet_send(); | |
2059 | packet_write_wait(); | |
2060 | ||
fa08c86b | 2061 | debug("Sent %d bit server key and %d bit host key.", |
2062 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
2063 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); | |
5260325f | 2064 | |
2065 | /* Read clients reply (cipher type and session key). */ | |
54a5250f | 2066 | packet_read_expect(SSH_CMSG_SESSION_KEY); |
5260325f | 2067 | |
2d86a6cc | 2068 | /* Get cipher type and check whether we accept this. */ |
5260325f | 2069 | cipher_type = packet_get_char(); |
2070 | ||
94ec8c6b | 2071 | if (!(cipher_mask_ssh1(0) & (1 << cipher_type))) |
2d86a6cc | 2072 | packet_disconnect("Warning: client selects unsupported cipher."); |
2073 | ||
5260325f | 2074 | /* Get check bytes from the packet. These must match those we |
2075 | sent earlier with the public key packet. */ | |
2076 | for (i = 0; i < 8; i++) | |
7b2ea3a1 | 2077 | if (cookie[i] != packet_get_char()) |
5260325f | 2078 | packet_disconnect("IP Spoofing check bytes do not match."); |
2079 | ||
2080 | debug("Encryption type: %.200s", cipher_name(cipher_type)); | |
2081 | ||
2082 | /* Get the encrypted integer. */ | |
b775c6f2 | 2083 | if ((session_key_int = BN_new()) == NULL) |
2084 | fatal("do_ssh1_kex: BN_new failed"); | |
20b279e6 | 2085 | packet_get_bignum(session_key_int); |
5260325f | 2086 | |
5260325f | 2087 | protocol_flags = packet_get_int(); |
2088 | packet_set_protocol_flags(protocol_flags); | |
95500969 | 2089 | packet_check_eom(); |
5260325f | 2090 | |
4f08e98d | 2091 | /* Decrypt session_key_int using host/server keys */ |
1853d1ef | 2092 | rsafail = PRIVSEP(ssh1_session_key(session_key_int)); |
2093 | ||
aa3378df | 2094 | /* |
2095 | * Extract session key from the decrypted integer. The key is in the | |
2096 | * least significant 256 bits of the integer; the first byte of the | |
2097 | * key is in the highest bits. | |
2098 | */ | |
46aa2d1f | 2099 | if (!rsafail) { |
e516451d | 2100 | (void) BN_mask_bits(session_key_int, sizeof(session_key) * 8); |
46aa2d1f | 2101 | len = BN_num_bytes(session_key_int); |
2ceb8101 | 2102 | if (len < 0 || (u_int)len > sizeof(session_key)) { |
e516451d | 2103 | error("do_ssh1_kex: bad session key len from %s: " |
5ca51e19 | 2104 | "session_key_int %d > sizeof(session_key) %lu", |
2105 | get_remote_ipaddr(), len, (u_long)sizeof(session_key)); | |
46aa2d1f | 2106 | rsafail++; |
2107 | } else { | |
2108 | memset(session_key, 0, sizeof(session_key)); | |
2109 | BN_bn2bin(session_key_int, | |
2110 | session_key + sizeof(session_key) - len); | |
00be5382 | 2111 | |
8bbf1fa6 | 2112 | derive_ssh1_session_id( |
f2107e97 | 2113 | sensitive_data.ssh1_host_key->rsa->n, |
8bbf1fa6 | 2114 | sensitive_data.server_key->rsa->n, |
2115 | cookie, session_id); | |
00be5382 | 2116 | /* |
2117 | * Xor the first 16 bytes of the session key with the | |
2118 | * session id. | |
2119 | */ | |
2120 | for (i = 0; i < 16; i++) | |
2121 | session_key[i] ^= session_id[i]; | |
46aa2d1f | 2122 | } |
2123 | } | |
2124 | if (rsafail) { | |
00be5382 | 2125 | int bytes = BN_num_bytes(session_key_int); |
f6b1ba8f | 2126 | u_char *buf = xmalloc(bytes); |
00be5382 | 2127 | MD5_CTX md; |
2128 | ||
bbe88b6d | 2129 | logit("do_connection: generating a fake encryption key"); |
00be5382 | 2130 | BN_bn2bin(session_key_int, buf); |
2131 | MD5_Init(&md); | |
2132 | MD5_Update(&md, buf, bytes); | |
2133 | MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); | |
2134 | MD5_Final(session_key, &md); | |
2135 | MD5_Init(&md); | |
2136 | MD5_Update(&md, session_key, 16); | |
2137 | MD5_Update(&md, buf, bytes); | |
2138 | MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); | |
2139 | MD5_Final(session_key + 16, &md); | |
2140 | memset(buf, 0, bytes); | |
2141 | xfree(buf); | |
0572fe75 | 2142 | for (i = 0; i < 16; i++) |
2143 | session_id[i] = session_key[i] ^ session_key[i + 16]; | |
46aa2d1f | 2144 | } |
1853d1ef | 2145 | /* Destroy the private and public keys. No longer. */ |
63284fbb | 2146 | destroy_sensitive_data(); |
00be5382 | 2147 | |
1853d1ef | 2148 | if (use_privsep) |
2149 | mm_ssh1_session_id(session_id); | |
2150 | ||
7b2ea3a1 | 2151 | /* Destroy the decrypted integer. It is no longer needed. */ |
2152 | BN_clear_free(session_key_int); | |
2153 | ||
5260325f | 2154 | /* Set the session key. From this on all communications will be encrypted. */ |
2155 | packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type); | |
2156 | ||
2157 | /* Destroy our copy of the session key. It is no longer needed. */ | |
2158 | memset(session_key, 0, sizeof(session_key)); | |
2159 | ||
2160 | debug("Received session key; encryption turned on."); | |
2161 | ||
c242fc96 | 2162 | /* Send an acknowledgment packet. Note that this packet is sent encrypted. */ |
5260325f | 2163 | packet_start(SSH_SMSG_SUCCESS); |
2164 | packet_send(); | |
2165 | packet_write_wait(); | |
5260325f | 2166 | } |
e78a59f5 | 2167 | |
2168 | /* | |
2169 | * SSH2 key exchange: diffie-hellman-group1-sha1 | |
2170 | */ | |
396c147e | 2171 | static void |
1e3b8b07 | 2172 | do_ssh2_kex(void) |
e78a59f5 | 2173 | { |
e78a59f5 | 2174 | Kex *kex; |
e78a59f5 | 2175 | |
a8be9f80 | 2176 | if (options.ciphers != NULL) { |
6ae2364d | 2177 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = |
a8be9f80 | 2178 | myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; |
2179 | } | |
1ad64a93 | 2180 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = |
2181 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]); | |
2182 | myproposal[PROPOSAL_ENC_ALGS_STOC] = | |
2183 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); | |
2184 | ||
b2552997 | 2185 | if (options.macs != NULL) { |
2186 | myproposal[PROPOSAL_MAC_ALGS_CTOS] = | |
2187 | myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; | |
2188 | } | |
07200973 | 2189 | if (options.compression == COMP_NONE) { |
636f76ca | 2190 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = |
2191 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "none"; | |
07200973 | 2192 | } else if (options.compression == COMP_DELAYED) { |
2193 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = | |
2194 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com"; | |
636f76ca | 2195 | } |
3efa8ea9 | 2196 | |
fa08c86b | 2197 | myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = list_hostkey_types(); |
2198 | ||
7a37c112 | 2199 | /* start key exchange */ |
d8ee838b | 2200 | kex = kex_setup(myproposal); |
98a58eda | 2201 | kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server; |
41e5bd9a | 2202 | kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server; |
98a58eda | 2203 | kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; |
2ff8003a | 2204 | kex->kex[KEX_DH_GEX_SHA256] = kexgex_server; |
a5c9ffdb | 2205 | kex->server = 1; |
2206 | kex->client_version_string=client_version_string; | |
2207 | kex->server_version_string=server_version_string; | |
2208 | kex->load_host_key=&get_hostkey_by_type; | |
1853d1ef | 2209 | kex->host_key_index=&get_hostkey_index; |
94ec8c6b | 2210 | |
7a37c112 | 2211 | xxx_kex = kex; |
2212 | ||
c422989b | 2213 | dispatch_run(DISPATCH_BLOCK, &kex->done, kex); |
94ec8c6b | 2214 | |
d1ac6175 | 2215 | session_id2 = kex->session_id; |
2216 | session_id2_len = kex->session_id_len; | |
2217 | ||
94ec8c6b | 2218 | #ifdef DEBUG_KEXDH |
2219 | /* send 1st encrypted/maced/compressed message */ | |
2220 | packet_start(SSH2_MSG_IGNORE); | |
2221 | packet_put_cstring("markus"); | |
2222 | packet_send(); | |
2223 | packet_write_wait(); | |
2224 | #endif | |
a5c9ffdb | 2225 | debug("KEX done"); |
e78a59f5 | 2226 | } |
2362db19 | 2227 | |
2228 | /* server specific fatal cleanup */ | |
2229 | void | |
2230 | cleanup_exit(int i) | |
2231 | { | |
2232 | if (the_authctxt) | |
2233 | do_cleanup(the_authctxt); | |
6039eeef | 2234 | #ifdef SSH_AUDIT_EVENTS |
c00e4d75 | 2235 | /* done after do_cleanup so it can cancel the PAM auth 'thread' */ |
2236 | if (!use_privsep || mm_is_monitor()) | |
6039eeef | 2237 | audit_event(SSH_CONNECTION_ABANDON); |
c00e4d75 | 2238 | #endif |
2362db19 | 2239 | _exit(i); |
2240 | } |