blob: d6e63131768e938d76f8aa1a3fabdfb9ca7d0846 [file] [log] [blame]
Damien Miller62116dc2001-12-24 01:41:47 +11001/*
Damien Miller7b10ef42002-01-21 23:44:12 +11002 * Copyright (c) 2001-2002 Damien Miller. All rights reserved.
Damien Miller62116dc2001-12-24 01:41:47 +11003 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
14 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
15 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
16 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
17 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
18 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
19 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
20 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
21 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
22 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
23 */
24
25#include "includes.h"
26
Damien Miller3717cda2006-03-15 14:02:36 +110027#include <sys/types.h>
28#include <sys/resource.h>
29#include <sys/stat.h>
30#include <sys/wait.h>
31
32#ifdef HAVE_SYS_UN_H
33# include <sys/un.h>
34#endif
35
36#include <signal.h>
37
Damien Miller62116dc2001-12-24 01:41:47 +110038#include <openssl/rand.h>
39#include <openssl/sha.h>
40#include <openssl/crypto.h>
41
42/* SunOS 4.4.4 needs this */
43#ifdef HAVE_FLOATINGPOINT_H
44# include <floatingpoint.h>
45#endif /* HAVE_FLOATINGPOINT_H */
46
47#include "misc.h"
48#include "xmalloc.h"
49#include "atomicio.h"
50#include "pathnames.h"
51#include "log.h"
52
Damien Miller3717cda2006-03-15 14:02:36 +110053RCSID("$Id: ssh-rand-helper.c,v 1.27 2006/03/15 03:02:36 djm Exp $");
Damien Miller7b10ef42002-01-21 23:44:12 +110054
55/* Number of bytes we write out */
56#define OUTPUT_SEED_SIZE 48
57
58/* Length of on-disk seedfiles */
59#define SEED_FILE_SIZE 1024
60
61/* Maximum number of command-line arguments to read from file */
62#define NUM_ARGS 10
63
64/* Minimum number of usable commands to be considered sufficient */
65#define MIN_ENTROPY_SOURCES 16
66
67/* Path to on-disk seed file (relative to user's home directory */
68#ifndef SSH_PRNG_SEED_FILE
69# define SSH_PRNG_SEED_FILE _PATH_SSH_USER_DIR"/prng_seed"
70#endif
71
72/* Path to PRNG commands list */
73#ifndef SSH_PRNG_COMMAND_FILE
Damien Miller05eda432002-02-10 18:32:28 +110074# define SSH_PRNG_COMMAND_FILE SSHDIR "/ssh_prng_cmds"
Damien Miller7b10ef42002-01-21 23:44:12 +110075#endif
76
Kevin Steves94435082001-12-25 04:32:58 +000077extern char *__progname;
Kevin Steves94435082001-12-25 04:32:58 +000078
Damien Miller62116dc2001-12-24 01:41:47 +110079#define WHITESPACE " \t\n"
80
81#ifndef RUSAGE_SELF
82# define RUSAGE_SELF 0
83#endif
84#ifndef RUSAGE_CHILDREN
85# define RUSAGE_CHILDREN 0
86#endif
87
Damien Millerc46cc542002-01-22 21:58:27 +110088#if !defined(PRNGD_SOCKET) && !defined(PRNGD_PORT)
Damien Miller7b10ef42002-01-21 23:44:12 +110089# define USE_SEED_FILES
Damien Miller62116dc2001-12-24 01:41:47 +110090#endif
91
Damien Miller7b10ef42002-01-21 23:44:12 +110092typedef struct {
93 /* Proportion of data that is entropy */
94 double rate;
95 /* Counter goes positive if this command times out */
96 unsigned int badness;
97 /* Increases by factor of two each timeout */
98 unsigned int sticky_badness;
99 /* Path to executable */
100 char *path;
101 /* argv to pass to executable */
102 char *args[NUM_ARGS]; /* XXX: arbitrary limit */
103 /* full command string (debug) */
104 char *cmdstring;
105} entropy_cmd_t;
106
107/* slow command timeouts (all in milliseconds) */
108/* static int entropy_timeout_default = ENTROPY_TIMEOUT_MSEC; */
109static int entropy_timeout_current = ENTROPY_TIMEOUT_MSEC;
110
111/* this is initialised from a file, by prng_read_commands() */
112static entropy_cmd_t *entropy_cmds = NULL;
113
114/* Prototypes */
115double stir_from_system(void);
116double stir_from_programs(void);
117double stir_gettimeofday(double entropy_estimate);
118double stir_clock(double entropy_estimate);
119double stir_rusage(int who, double entropy_estimate);
Kevin Steves4bdb5472002-07-28 20:42:23 +0000120double hash_command_output(entropy_cmd_t *src, unsigned char *hash);
Damien Millera8e06ce2003-11-21 23:48:55 +1100121int get_random_bytes_prngd(unsigned char *buf, int len,
Damien Miller7b10ef42002-01-21 23:44:12 +1100122 unsigned short tcp_port, char *socket_path);
123
124/*
125 * Collect 'len' bytes of entropy into 'buf' from PRNGD/EGD daemon
126 * listening either on 'tcp_port', or via Unix domain socket at *
127 * 'socket_path'.
Damien Millera8e06ce2003-11-21 23:48:55 +1100128 * Either a non-zero tcp_port or a non-null socket_path must be
Damien Miller7b10ef42002-01-21 23:44:12 +1100129 * supplied.
130 * Returns 0 on success, -1 on error
131 */
Damien Miller62116dc2001-12-24 01:41:47 +1100132int
Damien Millera8e06ce2003-11-21 23:48:55 +1100133get_random_bytes_prngd(unsigned char *buf, int len,
Damien Miller7b10ef42002-01-21 23:44:12 +1100134 unsigned short tcp_port, char *socket_path)
Damien Miller62116dc2001-12-24 01:41:47 +1100135{
Damien Miller7b10ef42002-01-21 23:44:12 +1100136 int fd, addr_len, rval, errors;
Damien Miller52c8afe2005-06-19 10:19:43 +1000137 u_char msg[2];
Damien Miller7b10ef42002-01-21 23:44:12 +1100138 struct sockaddr_storage addr;
139 struct sockaddr_in *addr_in = (struct sockaddr_in *)&addr;
140 struct sockaddr_un *addr_un = (struct sockaddr_un *)&addr;
Damien Miller62116dc2001-12-24 01:41:47 +1100141 mysig_t old_sigpipe;
142
Damien Miller7b10ef42002-01-21 23:44:12 +1100143 /* Sanity checks */
144 if (socket_path == NULL && tcp_port == 0)
145 fatal("You must specify a port or a socket");
146 if (socket_path != NULL &&
147 strlen(socket_path) >= sizeof(addr_un->sun_path))
148 fatal("Random pool path is too long");
Damien Miller52c8afe2005-06-19 10:19:43 +1000149 if (len <= 0 || len > 255)
150 fatal("Too many bytes (%d) to read from PRNGD", len);
Damien Miller62116dc2001-12-24 01:41:47 +1100151
152 memset(&addr, '\0', sizeof(addr));
153
Damien Miller7b10ef42002-01-21 23:44:12 +1100154 if (tcp_port != 0) {
155 addr_in->sin_family = AF_INET;
156 addr_in->sin_addr.s_addr = htonl(INADDR_LOOPBACK);
157 addr_in->sin_port = htons(tcp_port);
158 addr_len = sizeof(*addr_in);
159 } else {
160 addr_un->sun_family = AF_UNIX;
161 strlcpy(addr_un->sun_path, socket_path,
162 sizeof(addr_un->sun_path));
163 addr_len = offsetof(struct sockaddr_un, sun_path) +
164 strlen(socket_path) + 1;
165 }
Damien Miller62116dc2001-12-24 01:41:47 +1100166
167 old_sigpipe = mysignal(SIGPIPE, SIG_IGN);
168
Damien Miller7b10ef42002-01-21 23:44:12 +1100169 errors = 0;
170 rval = -1;
Damien Miller62116dc2001-12-24 01:41:47 +1100171reopen:
Damien Miller7b10ef42002-01-21 23:44:12 +1100172 fd = socket(addr.ss_family, SOCK_STREAM, 0);
Damien Miller62116dc2001-12-24 01:41:47 +1100173 if (fd == -1) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100174 error("Couldn't create socket: %s", strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100175 goto done;
176 }
Damien Miller62116dc2001-12-24 01:41:47 +1100177
178 if (connect(fd, (struct sockaddr*)&addr, addr_len) == -1) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100179 if (tcp_port != 0) {
180 error("Couldn't connect to PRNGD port %d: %s",
181 tcp_port, strerror(errno));
182 } else {
183 error("Couldn't connect to PRNGD socket \"%s\": %s",
184 addr_un->sun_path, strerror(errno));
185 }
Damien Miller62116dc2001-12-24 01:41:47 +1100186 goto done;
187 }
188
189 /* Send blocking read request to PRNGD */
190 msg[0] = 0x02;
191 msg[1] = len;
192
Darren Tucker8661b562003-07-06 15:20:46 +1000193 if (atomicio(vwrite, fd, msg, sizeof(msg)) != sizeof(msg)) {
Damien Miller62116dc2001-12-24 01:41:47 +1100194 if (errno == EPIPE && errors < 10) {
195 close(fd);
196 errors++;
197 goto reopen;
198 }
199 error("Couldn't write to PRNGD socket: %s",
200 strerror(errno));
201 goto done;
202 }
203
Damien Miller52c8afe2005-06-19 10:19:43 +1000204 if (atomicio(read, fd, buf, len) != (size_t)len) {
Damien Miller62116dc2001-12-24 01:41:47 +1100205 if (errno == EPIPE && errors < 10) {
206 close(fd);
207 errors++;
208 goto reopen;
209 }
210 error("Couldn't read from PRNGD socket: %s",
211 strerror(errno));
212 goto done;
213 }
214
Damien Miller7b10ef42002-01-21 23:44:12 +1100215 rval = 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100216done:
217 mysignal(SIGPIPE, old_sigpipe);
218 if (fd != -1)
219 close(fd);
Damien Miller7b10ef42002-01-21 23:44:12 +1100220 return rval;
Damien Miller62116dc2001-12-24 01:41:47 +1100221}
222
Darren Tucker8686ed72004-12-20 12:05:08 +1100223static int
224seed_from_prngd(unsigned char *buf, size_t bytes)
225{
226#ifdef PRNGD_PORT
227 debug("trying egd/prngd port %d", PRNGD_PORT);
228 if (get_random_bytes_prngd(buf, bytes, PRNGD_PORT, NULL) == 0)
229 return 0;
230#endif
231#ifdef PRNGD_SOCKET
232 debug("trying egd/prngd socket %s", PRNGD_SOCKET);
233 if (get_random_bytes_prngd(buf, bytes, 0, PRNGD_SOCKET) == 0)
234 return 0;
235#endif
236 return -1;
237}
238
Damien Miller62116dc2001-12-24 01:41:47 +1100239double
240stir_gettimeofday(double entropy_estimate)
241{
242 struct timeval tv;
243
244 if (gettimeofday(&tv, NULL) == -1)
245 fatal("Couldn't gettimeofday: %s", strerror(errno));
246
247 RAND_add(&tv, sizeof(tv), entropy_estimate);
248
Damien Miller7b10ef42002-01-21 23:44:12 +1100249 return entropy_estimate;
Damien Miller62116dc2001-12-24 01:41:47 +1100250}
251
252double
253stir_clock(double entropy_estimate)
254{
255#ifdef HAVE_CLOCK
256 clock_t c;
257
258 c = clock();
259 RAND_add(&c, sizeof(c), entropy_estimate);
260
Damien Miller7b10ef42002-01-21 23:44:12 +1100261 return entropy_estimate;
Damien Miller62116dc2001-12-24 01:41:47 +1100262#else /* _HAVE_CLOCK */
Damien Miller7b10ef42002-01-21 23:44:12 +1100263 return 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100264#endif /* _HAVE_CLOCK */
265}
266
267double
268stir_rusage(int who, double entropy_estimate)
269{
270#ifdef HAVE_GETRUSAGE
271 struct rusage ru;
272
273 if (getrusage(who, &ru) == -1)
Damien Miller7b10ef42002-01-21 23:44:12 +1100274 return 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100275
276 RAND_add(&ru, sizeof(ru), entropy_estimate);
277
Damien Miller7b10ef42002-01-21 23:44:12 +1100278 return entropy_estimate;
Damien Miller62116dc2001-12-24 01:41:47 +1100279#else /* _HAVE_GETRUSAGE */
Damien Miller7b10ef42002-01-21 23:44:12 +1100280 return 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100281#endif /* _HAVE_GETRUSAGE */
282}
283
Damien Miller62116dc2001-12-24 01:41:47 +1100284static int
Damien Miller7b10ef42002-01-21 23:44:12 +1100285timeval_diff(struct timeval *t1, struct timeval *t2)
286{
Damien Miller62116dc2001-12-24 01:41:47 +1100287 int secdiff, usecdiff;
288
289 secdiff = t2->tv_sec - t1->tv_sec;
290 usecdiff = (secdiff*1000000) + (t2->tv_usec - t1->tv_usec);
291 return (int)(usecdiff / 1000);
292}
293
294double
Kevin Steves4bdb5472002-07-28 20:42:23 +0000295hash_command_output(entropy_cmd_t *src, unsigned char *hash)
Damien Miller62116dc2001-12-24 01:41:47 +1100296{
Damien Miller7b10ef42002-01-21 23:44:12 +1100297 char buf[8192];
Damien Miller62116dc2001-12-24 01:41:47 +1100298 fd_set rdset;
Damien Miller7b10ef42002-01-21 23:44:12 +1100299 int bytes_read, cmd_eof, error_abort, msec_elapsed, p[2];
300 int status, total_bytes_read;
301 static int devnull = -1;
Damien Miller62116dc2001-12-24 01:41:47 +1100302 pid_t pid;
Damien Miller62116dc2001-12-24 01:41:47 +1100303 SHA_CTX sha;
Damien Miller7b10ef42002-01-21 23:44:12 +1100304 struct timeval tv_start, tv_current;
Damien Miller62116dc2001-12-24 01:41:47 +1100305
306 debug3("Reading output from \'%s\'", src->cmdstring);
307
308 if (devnull == -1) {
309 devnull = open("/dev/null", O_RDWR);
310 if (devnull == -1)
Damien Millera8e06ce2003-11-21 23:48:55 +1100311 fatal("Couldn't open /dev/null: %s",
Damien Miller7b10ef42002-01-21 23:44:12 +1100312 strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100313 }
314
315 if (pipe(p) == -1)
316 fatal("Couldn't open pipe: %s", strerror(errno));
317
318 (void)gettimeofday(&tv_start, NULL); /* record start time */
319
320 switch (pid = fork()) {
321 case -1: /* Error */
322 close(p[0]);
323 close(p[1]);
324 fatal("Couldn't fork: %s", strerror(errno));
325 /* NOTREACHED */
326 case 0: /* Child */
327 dup2(devnull, STDIN_FILENO);
328 dup2(p[1], STDOUT_FILENO);
329 dup2(p[1], STDERR_FILENO);
330 close(p[0]);
331 close(p[1]);
332 close(devnull);
333
334 execv(src->path, (char**)(src->args));
Damien Miller7b10ef42002-01-21 23:44:12 +1100335
Damien Millera8e06ce2003-11-21 23:48:55 +1100336 debug("(child) Couldn't exec '%s': %s",
Damien Miller7b10ef42002-01-21 23:44:12 +1100337 src->cmdstring, strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100338 _exit(-1);
339 default: /* Parent */
340 break;
341 }
342
343 RAND_add(&pid, sizeof(&pid), 0.0);
344
345 close(p[1]);
346
347 /* Hash output from child */
348 SHA1_Init(&sha);
Damien Miller62116dc2001-12-24 01:41:47 +1100349
Damien Miller7b10ef42002-01-21 23:44:12 +1100350 cmd_eof = error_abort = msec_elapsed = total_bytes_read = 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100351 while (!error_abort && !cmd_eof) {
352 int ret;
353 struct timeval tv;
354 int msec_remaining;
355
356 (void) gettimeofday(&tv_current, 0);
Damien Miller7b10ef42002-01-21 23:44:12 +1100357 msec_elapsed = timeval_diff(&tv_start, &tv_current);
Damien Miller62116dc2001-12-24 01:41:47 +1100358 if (msec_elapsed >= entropy_timeout_current) {
359 error_abort=1;
360 continue;
361 }
362 msec_remaining = entropy_timeout_current - msec_elapsed;
363
364 FD_ZERO(&rdset);
365 FD_SET(p[0], &rdset);
Damien Miller7b10ef42002-01-21 23:44:12 +1100366 tv.tv_sec = msec_remaining / 1000;
Damien Miller62116dc2001-12-24 01:41:47 +1100367 tv.tv_usec = (msec_remaining % 1000) * 1000;
368
Damien Miller7b10ef42002-01-21 23:44:12 +1100369 ret = select(p[0] + 1, &rdset, NULL, NULL, &tv);
Damien Miller62116dc2001-12-24 01:41:47 +1100370
371 RAND_add(&tv, sizeof(tv), 0.0);
372
373 switch (ret) {
374 case 0:
375 /* timer expired */
376 error_abort = 1;
Damien Miller5a5da882002-10-21 10:13:35 +1000377 kill(pid, SIGINT);
Damien Miller62116dc2001-12-24 01:41:47 +1100378 break;
379 case 1:
380 /* command input */
381 do {
382 bytes_read = read(p[0], buf, sizeof(buf));
383 } while (bytes_read == -1 && errno == EINTR);
384 RAND_add(&bytes_read, sizeof(&bytes_read), 0.0);
385 if (bytes_read == -1) {
386 error_abort = 1;
387 break;
388 } else if (bytes_read) {
389 SHA1_Update(&sha, buf, bytes_read);
390 total_bytes_read += bytes_read;
391 } else {
392 cmd_eof = 1;
393 }
394 break;
395 case -1:
396 default:
397 /* error */
Damien Millera8e06ce2003-11-21 23:48:55 +1100398 debug("Command '%s': select() failed: %s",
Damien Miller7b10ef42002-01-21 23:44:12 +1100399 src->cmdstring, strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100400 error_abort = 1;
401 break;
402 }
403 }
404
405 SHA1_Final(hash, &sha);
406
407 close(p[0]);
408
409 debug3("Time elapsed: %d msec", msec_elapsed);
410
411 if (waitpid(pid, &status, 0) == -1) {
Damien Millerb6f72f52005-07-17 17:26:43 +1000412 error("Couldn't wait for child '%s' completion: %s",
413 src->cmdstring, strerror(errno));
Damien Miller7b10ef42002-01-21 23:44:12 +1100414 return 0.0;
Damien Miller62116dc2001-12-24 01:41:47 +1100415 }
416
417 RAND_add(&status, sizeof(&status), 0.0);
418
419 if (error_abort) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100420 /*
421 * Closing p[0] on timeout causes the entropy command to
Damien Millera8e06ce2003-11-21 23:48:55 +1100422 * SIGPIPE. Take whatever output we got, and mark this
423 * command as slow
Damien Miller7b10ef42002-01-21 23:44:12 +1100424 */
Damien Miller62116dc2001-12-24 01:41:47 +1100425 debug2("Command '%s' timed out", src->cmdstring);
426 src->sticky_badness *= 2;
427 src->badness = src->sticky_badness;
Damien Miller7b10ef42002-01-21 23:44:12 +1100428 return total_bytes_read;
Damien Miller62116dc2001-12-24 01:41:47 +1100429 }
430
431 if (WIFEXITED(status)) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100432 if (WEXITSTATUS(status) == 0) {
433 return total_bytes_read;
Damien Miller62116dc2001-12-24 01:41:47 +1100434 } else {
Damien Miller7b10ef42002-01-21 23:44:12 +1100435 debug2("Command '%s' exit status was %d",
436 src->cmdstring, WEXITSTATUS(status));
Damien Miller62116dc2001-12-24 01:41:47 +1100437 src->badness = src->sticky_badness = 128;
Damien Miller7b10ef42002-01-21 23:44:12 +1100438 return 0.0;
Damien Miller62116dc2001-12-24 01:41:47 +1100439 }
440 } else if (WIFSIGNALED(status)) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100441 debug2("Command '%s' returned on uncaught signal %d !",
442 src->cmdstring, status);
Damien Miller62116dc2001-12-24 01:41:47 +1100443 src->badness = src->sticky_badness = 128;
Damien Miller7b10ef42002-01-21 23:44:12 +1100444 return 0.0;
Damien Miller62116dc2001-12-24 01:41:47 +1100445 } else
Damien Miller7b10ef42002-01-21 23:44:12 +1100446 return 0.0;
447}
448
449double
450stir_from_system(void)
451{
452 double total_entropy_estimate;
453 long int i;
454
455 total_entropy_estimate = 0;
456
457 i = getpid();
458 RAND_add(&i, sizeof(i), 0.5);
459 total_entropy_estimate += 0.1;
460
461 i = getppid();
462 RAND_add(&i, sizeof(i), 0.5);
463 total_entropy_estimate += 0.1;
464
465 i = getuid();
466 RAND_add(&i, sizeof(i), 0.0);
467 i = getgid();
468 RAND_add(&i, sizeof(i), 0.0);
469
470 total_entropy_estimate += stir_gettimeofday(1.0);
471 total_entropy_estimate += stir_clock(0.5);
472 total_entropy_estimate += stir_rusage(RUSAGE_SELF, 2.0);
473
474 return total_entropy_estimate;
475}
476
477double
478stir_from_programs(void)
479{
480 int c;
481 double entropy, total_entropy;
Kevin Steves4bdb5472002-07-28 20:42:23 +0000482 unsigned char hash[SHA_DIGEST_LENGTH];
Damien Miller7b10ef42002-01-21 23:44:12 +1100483
484 total_entropy = 0;
485 for(c = 0; entropy_cmds[c].path != NULL; c++) {
486 if (!entropy_cmds[c].badness) {
487 /* Hash output from command */
488 entropy = hash_command_output(&entropy_cmds[c],
489 hash);
490
491 /* Scale back estimate by command's rate */
492 entropy *= entropy_cmds[c].rate;
493
494 /* Upper bound of entropy is SHA_DIGEST_LENGTH */
495 if (entropy > SHA_DIGEST_LENGTH)
496 entropy = SHA_DIGEST_LENGTH;
497
498 /* Stir it in */
499 RAND_add(hash, sizeof(hash), entropy);
500
Damien Millera8e06ce2003-11-21 23:48:55 +1100501 debug3("Got %0.2f bytes of entropy from '%s'",
Damien Miller7b10ef42002-01-21 23:44:12 +1100502 entropy, entropy_cmds[c].cmdstring);
503
504 total_entropy += entropy;
505
506 /* Execution time should be a bit unpredictable */
507 total_entropy += stir_gettimeofday(0.05);
508 total_entropy += stir_clock(0.05);
509 total_entropy += stir_rusage(RUSAGE_SELF, 0.1);
510 total_entropy += stir_rusage(RUSAGE_CHILDREN, 0.1);
511 } else {
512 debug2("Command '%s' disabled (badness %d)",
Damien Millera8e06ce2003-11-21 23:48:55 +1100513 entropy_cmds[c].cmdstring,
Damien Miller7b10ef42002-01-21 23:44:12 +1100514 entropy_cmds[c].badness);
515
516 if (entropy_cmds[c].badness > 0)
517 entropy_cmds[c].badness--;
518 }
519 }
520
521 return total_entropy;
Damien Miller62116dc2001-12-24 01:41:47 +1100522}
523
524/*
525 * prng seedfile functions
526 */
527int
Damien Miller7b10ef42002-01-21 23:44:12 +1100528prng_check_seedfile(char *filename)
529{
Damien Miller62116dc2001-12-24 01:41:47 +1100530 struct stat st;
531
Damien Miller7b10ef42002-01-21 23:44:12 +1100532 /*
Damien Millera8e06ce2003-11-21 23:48:55 +1100533 * XXX raceable: eg replace seed between this stat and subsequent
534 * open. Not such a problem because we don't really trust the
Damien Miller7b10ef42002-01-21 23:44:12 +1100535 * seed file anyway.
536 * XXX: use secure path checking as elsewhere in OpenSSH
537 */
Damien Miller62116dc2001-12-24 01:41:47 +1100538 if (lstat(filename, &st) == -1) {
539 /* Give up on hard errors */
540 if (errno != ENOENT)
Damien Miller7b10ef42002-01-21 23:44:12 +1100541 debug("WARNING: Couldn't stat random seed file "
542 "\"%.100s\": %s", filename, strerror(errno));
543 return 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100544 }
545
546 /* regular file? */
547 if (!S_ISREG(st.st_mode))
Damien Miller7b10ef42002-01-21 23:44:12 +1100548 fatal("PRNG seedfile %.100s is not a regular file",
549 filename);
Damien Miller62116dc2001-12-24 01:41:47 +1100550
551 /* mode 0600, owned by root or the current user? */
552 if (((st.st_mode & 0177) != 0) || !(st.st_uid == getuid())) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100553 debug("WARNING: PRNG seedfile %.100s must be mode 0600, "
Damien Millerc46b6bc2003-05-16 15:51:44 +1000554 "owned by uid %li", filename, (long int)getuid());
Damien Miller7b10ef42002-01-21 23:44:12 +1100555 return 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100556 }
557
Damien Miller7b10ef42002-01-21 23:44:12 +1100558 return 1;
Damien Miller62116dc2001-12-24 01:41:47 +1100559}
560
561void
Damien Miller7b10ef42002-01-21 23:44:12 +1100562prng_write_seedfile(void)
563{
Damien Millered462d92005-02-16 13:02:45 +1100564 int fd, save_errno;
Kevin Steves4bdb5472002-07-28 20:42:23 +0000565 unsigned char seed[SEED_FILE_SIZE];
Damien Millered462d92005-02-16 13:02:45 +1100566 char filename[MAXPATHLEN], tmpseed[MAXPATHLEN];
Damien Miller62116dc2001-12-24 01:41:47 +1100567 struct passwd *pw;
Damien Millered462d92005-02-16 13:02:45 +1100568 mode_t old_umask;
Damien Miller62116dc2001-12-24 01:41:47 +1100569
570 pw = getpwuid(getuid());
571 if (pw == NULL)
Damien Miller7b10ef42002-01-21 23:44:12 +1100572 fatal("Couldn't get password entry for current user "
Damien Millerc46b6bc2003-05-16 15:51:44 +1000573 "(%li): %s", (long int)getuid(), strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100574
575 /* Try to ensure that the parent directory is there */
576 snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir,
Damien Miller7b10ef42002-01-21 23:44:12 +1100577 _PATH_SSH_USER_DIR);
Damien Miller62116dc2001-12-24 01:41:47 +1100578 mkdir(filename, 0700);
579
580 snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir,
Damien Miller7b10ef42002-01-21 23:44:12 +1100581 SSH_PRNG_SEED_FILE);
Damien Miller62116dc2001-12-24 01:41:47 +1100582
Damien Millered462d92005-02-16 13:02:45 +1100583 strlcpy(tmpseed, filename, sizeof(tmpseed));
584 if (strlcat(tmpseed, ".XXXXXXXXXX", sizeof(tmpseed)) >=
585 sizeof(tmpseed))
586 fatal("PRNG seed filename too long");
Damien Miller62116dc2001-12-24 01:41:47 +1100587
Damien Millercafbcc72003-03-17 16:13:53 +1100588 if (RAND_bytes(seed, sizeof(seed)) <= 0)
Ben Lindstromda4d9cf2003-09-22 15:36:15 +0000589 fatal("PRNG seed extraction failed");
Damien Miller62116dc2001-12-24 01:41:47 +1100590
591 /* Don't care if the seed doesn't exist */
592 prng_check_seedfile(filename);
593
Damien Millered462d92005-02-16 13:02:45 +1100594 old_umask = umask(0177);
595
596 if ((fd = mkstemp(tmpseed)) == -1) {
597 debug("WARNING: couldn't make temporary PRNG seedfile %.100s "
598 "(%.100s)", tmpseed, strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100599 } else {
Damien Millered462d92005-02-16 13:02:45 +1100600 debug("writing PRNG seed to file %.100s", tmpseed);
601 if (atomicio(vwrite, fd, &seed, sizeof(seed)) < sizeof(seed)) {
602 save_errno = errno;
603 close(fd);
604 unlink(tmpseed);
Damien Miller7b10ef42002-01-21 23:44:12 +1100605 fatal("problem writing PRNG seedfile %.100s "
Damien Millered462d92005-02-16 13:02:45 +1100606 "(%.100s)", filename, strerror(save_errno));
607 }
Damien Miller62116dc2001-12-24 01:41:47 +1100608 close(fd);
Damien Millered462d92005-02-16 13:02:45 +1100609 debug("moving temporary PRNG seed to file %.100s", filename);
610 if (rename(tmpseed, filename) == -1) {
611 save_errno = errno;
612 unlink(tmpseed);
613 fatal("problem renaming PRNG seedfile from %.100s "
Damien Miller94cf4c82005-07-17 17:04:47 +1000614 "to %.100s (%.100s)", tmpseed, filename,
Damien Millered462d92005-02-16 13:02:45 +1100615 strerror(save_errno));
616 }
Damien Miller62116dc2001-12-24 01:41:47 +1100617 }
Damien Millered462d92005-02-16 13:02:45 +1100618 umask(old_umask);
Damien Miller62116dc2001-12-24 01:41:47 +1100619}
620
621void
Damien Miller7b10ef42002-01-21 23:44:12 +1100622prng_read_seedfile(void)
623{
Damien Miller62116dc2001-12-24 01:41:47 +1100624 int fd;
Damien Miller7b10ef42002-01-21 23:44:12 +1100625 char seed[SEED_FILE_SIZE], filename[MAXPATHLEN];
Damien Miller62116dc2001-12-24 01:41:47 +1100626 struct passwd *pw;
627
628 pw = getpwuid(getuid());
629 if (pw == NULL)
Damien Miller7b10ef42002-01-21 23:44:12 +1100630 fatal("Couldn't get password entry for current user "
Damien Millerc46b6bc2003-05-16 15:51:44 +1000631 "(%li): %s", (long int)getuid(), strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100632
633 snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir,
634 SSH_PRNG_SEED_FILE);
635
636 debug("loading PRNG seed from file %.100s", filename);
637
638 if (!prng_check_seedfile(filename)) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100639 verbose("Random seed file not found or invalid, ignoring.");
Damien Miller62116dc2001-12-24 01:41:47 +1100640 return;
641 }
642
643 /* open the file and read in the seed */
644 fd = open(filename, O_RDONLY);
645 if (fd == -1)
Damien Miller7b10ef42002-01-21 23:44:12 +1100646 fatal("could not open PRNG seedfile %.100s (%.100s)",
647 filename, strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100648
Damien Miller7b10ef42002-01-21 23:44:12 +1100649 if (atomicio(read, fd, &seed, sizeof(seed)) < sizeof(seed)) {
650 verbose("invalid or short read from PRNG seedfile "
651 "%.100s - ignoring", filename);
Damien Miller62116dc2001-12-24 01:41:47 +1100652 memset(seed, '\0', sizeof(seed));
653 }
654 close(fd);
655
656 /* stir in the seed, with estimated entropy zero */
657 RAND_add(&seed, sizeof(seed), 0.0);
658}
659
660
661/*
662 * entropy command initialisation functions
663 */
664int
665prng_read_commands(char *cmdfilename)
666{
Damien Miller7b10ef42002-01-21 23:44:12 +1100667 char cmd[SEED_FILE_SIZE], *cp, line[1024], path[SEED_FILE_SIZE];
Damien Miller62116dc2001-12-24 01:41:47 +1100668 double est;
Damien Miller7b10ef42002-01-21 23:44:12 +1100669 entropy_cmd_t *entcmd;
670 FILE *f;
671 int cur_cmd, linenum, num_cmds, arg;
Damien Miller62116dc2001-12-24 01:41:47 +1100672
Damien Miller7b10ef42002-01-21 23:44:12 +1100673 if ((f = fopen(cmdfilename, "r")) == NULL) {
Damien Miller62116dc2001-12-24 01:41:47 +1100674 fatal("couldn't read entropy commands file %.100s: %.100s",
675 cmdfilename, strerror(errno));
676 }
677
Damien Miller7b10ef42002-01-21 23:44:12 +1100678 num_cmds = 64;
679 entcmd = xmalloc(num_cmds * sizeof(entropy_cmd_t));
680 memset(entcmd, '\0', num_cmds * sizeof(entropy_cmd_t));
Damien Miller62116dc2001-12-24 01:41:47 +1100681
682 /* Read in file */
Damien Miller7b10ef42002-01-21 23:44:12 +1100683 cur_cmd = linenum = 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100684 while (fgets(line, sizeof(line), f)) {
Damien Miller62116dc2001-12-24 01:41:47 +1100685 linenum++;
686
Damien Miller7b10ef42002-01-21 23:44:12 +1100687 /* Skip leading whitespace, blank lines and comments */
Damien Miller62116dc2001-12-24 01:41:47 +1100688 cp = line + strspn(line, WHITESPACE);
689 if ((*cp == 0) || (*cp == '#'))
690 continue; /* done with this line */
691
Damien Miller7b10ef42002-01-21 23:44:12 +1100692 /*
Damien Millera8e06ce2003-11-21 23:48:55 +1100693 * The first non-whitespace char should be a double quote
Damien Miller7b10ef42002-01-21 23:44:12 +1100694 * delimiting the commandline
695 */
Damien Miller62116dc2001-12-24 01:41:47 +1100696 if (*cp != '"') {
Damien Miller7b10ef42002-01-21 23:44:12 +1100697 error("bad entropy command, %.100s line %d",
698 cmdfilename, linenum);
Damien Miller62116dc2001-12-24 01:41:47 +1100699 continue;
700 }
701
Damien Miller7b10ef42002-01-21 23:44:12 +1100702 /*
703 * First token, command args (incl. argv[0]) in double
704 * quotes
705 */
Damien Miller62116dc2001-12-24 01:41:47 +1100706 cp = strtok(cp, "\"");
707 if (cp == NULL) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100708 error("missing or bad command string, %.100s "
709 "line %d -- ignored", cmdfilename, linenum);
Damien Miller62116dc2001-12-24 01:41:47 +1100710 continue;
711 }
712 strlcpy(cmd, cp, sizeof(cmd));
713
Damien Miller7b10ef42002-01-21 23:44:12 +1100714 /* Second token, full command path */
Damien Miller62116dc2001-12-24 01:41:47 +1100715 if ((cp = strtok(NULL, WHITESPACE)) == NULL) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100716 error("missing command path, %.100s "
717 "line %d -- ignored", cmdfilename, linenum);
Damien Miller62116dc2001-12-24 01:41:47 +1100718 continue;
719 }
720
Damien Miller7b10ef42002-01-21 23:44:12 +1100721 /* Did configure mark this as dead? */
Damien Miller62116dc2001-12-24 01:41:47 +1100722 if (strncmp("undef", cp, 5) == 0)
723 continue;
724
725 strlcpy(path, cp, sizeof(path));
726
Damien Miller7b10ef42002-01-21 23:44:12 +1100727 /* Third token, entropy rate estimate for this command */
Damien Miller62116dc2001-12-24 01:41:47 +1100728 if ((cp = strtok(NULL, WHITESPACE)) == NULL) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100729 error("missing entropy estimate, %.100s "
730 "line %d -- ignored", cmdfilename, linenum);
Damien Miller62116dc2001-12-24 01:41:47 +1100731 continue;
732 }
Damien Miller7b10ef42002-01-21 23:44:12 +1100733 est = strtod(cp, NULL);
Damien Miller62116dc2001-12-24 01:41:47 +1100734
735 /* end of line */
736 if ((cp = strtok(NULL, WHITESPACE)) != NULL) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100737 error("garbage at end of line %d in %.100s "
738 "-- ignored", linenum, cmdfilename);
Damien Miller62116dc2001-12-24 01:41:47 +1100739 continue;
740 }
741
742 /* save the command for debug messages */
743 entcmd[cur_cmd].cmdstring = xstrdup(cmd);
744
745 /* split the command args */
746 cp = strtok(cmd, WHITESPACE);
747 arg = 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100748 do {
Damien Miller7b10ef42002-01-21 23:44:12 +1100749 entcmd[cur_cmd].args[arg] = xstrdup(cp);
Damien Miller62116dc2001-12-24 01:41:47 +1100750 arg++;
Damien Miller7b10ef42002-01-21 23:44:12 +1100751 } while(arg < NUM_ARGS && (cp = strtok(NULL, WHITESPACE)));
Damien Miller62116dc2001-12-24 01:41:47 +1100752
753 if (strtok(NULL, WHITESPACE))
Damien Miller7b10ef42002-01-21 23:44:12 +1100754 error("ignored extra commands (max %d), %.100s "
755 "line %d", NUM_ARGS, cmdfilename, linenum);
Damien Miller62116dc2001-12-24 01:41:47 +1100756
757 /* Copy the command path and rate estimate */
758 entcmd[cur_cmd].path = xstrdup(path);
759 entcmd[cur_cmd].rate = est;
760
761 /* Initialise other values */
762 entcmd[cur_cmd].sticky_badness = 1;
763
764 cur_cmd++;
765
Damien Miller7b10ef42002-01-21 23:44:12 +1100766 /*
767 * If we've filled the array, reallocate it twice the size
Damien Millera8e06ce2003-11-21 23:48:55 +1100768 * Do this now because even if this we're on the last
Damien Miller7b10ef42002-01-21 23:44:12 +1100769 * command we need another slot to mark the last entry
770 */
Damien Miller62116dc2001-12-24 01:41:47 +1100771 if (cur_cmd == num_cmds) {
772 num_cmds *= 2;
Damien Miller7b10ef42002-01-21 23:44:12 +1100773 entcmd = xrealloc(entcmd, num_cmds *
774 sizeof(entropy_cmd_t));
Damien Miller62116dc2001-12-24 01:41:47 +1100775 }
776 }
777
778 /* zero the last entry */
Damien Miller7b10ef42002-01-21 23:44:12 +1100779 memset(&entcmd[cur_cmd], '\0', sizeof(entropy_cmd_t));
Damien Miller62116dc2001-12-24 01:41:47 +1100780
781 /* trim to size */
Damien Miller7b10ef42002-01-21 23:44:12 +1100782 entropy_cmds = xrealloc(entcmd, (cur_cmd + 1) *
783 sizeof(entropy_cmd_t));
Damien Miller62116dc2001-12-24 01:41:47 +1100784
Damien Miller7b10ef42002-01-21 23:44:12 +1100785 debug("Loaded %d entropy commands from %.100s", cur_cmd,
786 cmdfilename);
Damien Miller62116dc2001-12-24 01:41:47 +1100787
Damien Miller7b10ef42002-01-21 23:44:12 +1100788 return cur_cmd < MIN_ENTROPY_SOURCES ? -1 : 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100789}
790
Damien Miller32e48182002-04-14 19:27:12 +1000791void
792usage(void)
793{
794 fprintf(stderr, "Usage: %s [options]\n", __progname);
795 fprintf(stderr, " -v Verbose; display verbose debugging messages.\n");
796 fprintf(stderr, " Multiple -v increases verbosity.\n");
Damien Miller7daf0442004-08-23 21:52:08 +1000797 fprintf(stderr, " -x Force output in hexadecimal (for debugging)\n");
Damien Miller32e48182002-04-14 19:27:12 +1000798 fprintf(stderr, " -X Force output in binary\n");
799 fprintf(stderr, " -b bytes Number of bytes to output (default %d)\n",
800 OUTPUT_SEED_SIZE);
801}
802
Damien Millera8e06ce2003-11-21 23:48:55 +1100803int
Damien Miller62116dc2001-12-24 01:41:47 +1100804main(int argc, char **argv)
805{
Damien Miller32e48182002-04-14 19:27:12 +1000806 unsigned char *buf;
807 int ret, ch, debug_level, output_hex, bytes;
808 extern char *optarg;
809 LogLevel ll;
Damien Miller62116dc2001-12-24 01:41:47 +1100810
Damien Miller59d3d5b2003-08-22 09:34:41 +1000811 __progname = ssh_get_progname(argv[0]);
Damien Miller62116dc2001-12-24 01:41:47 +1100812 log_init(argv[0], SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_USER, 1);
813
Damien Miller32e48182002-04-14 19:27:12 +1000814 ll = SYSLOG_LEVEL_INFO;
815 debug_level = output_hex = 0;
816 bytes = OUTPUT_SEED_SIZE;
817
818 /* Don't write binary data to a tty, unless we are forced to */
819 if (isatty(STDOUT_FILENO))
820 output_hex = 1;
Damien Miller787b2ec2003-11-21 23:56:47 +1100821
Damien Miller32e48182002-04-14 19:27:12 +1000822 while ((ch = getopt(argc, argv, "vxXhb:")) != -1) {
823 switch (ch) {
824 case 'v':
825 if (debug_level < 3)
826 ll = SYSLOG_LEVEL_DEBUG1 + debug_level++;
827 break;
828 case 'x':
829 output_hex = 1;
830 break;
831 case 'X':
832 output_hex = 0;
833 break;
834 case 'b':
835 if ((bytes = atoi(optarg)) <= 0)
836 fatal("Invalid number of output bytes");
837 break;
838 case 'h':
839 usage();
840 exit(0);
841 default:
842 error("Invalid commandline option");
843 usage();
844 }
845 }
846
847 log_init(argv[0], ll, SYSLOG_FACILITY_USER, 1);
Damien Miller787b2ec2003-11-21 23:56:47 +1100848
Damien Miller7b10ef42002-01-21 23:44:12 +1100849#ifdef USE_SEED_FILES
850 prng_read_seedfile();
851#endif
852
Damien Miller32e48182002-04-14 19:27:12 +1000853 buf = xmalloc(bytes);
854
Damien Miller7b10ef42002-01-21 23:44:12 +1100855 /*
856 * Seed the RNG from wherever we can
857 */
Damien Miller787b2ec2003-11-21 23:56:47 +1100858
Damien Miller7b10ef42002-01-21 23:44:12 +1100859 /* Take whatever is on the stack, but don't credit it */
Damien Miller32e48182002-04-14 19:27:12 +1000860 RAND_add(buf, bytes, 0);
Damien Miller7b10ef42002-01-21 23:44:12 +1100861
Damien Millera8e06ce2003-11-21 23:48:55 +1100862 debug("Seeded RNG with %i bytes from system calls",
Damien Miller7b10ef42002-01-21 23:44:12 +1100863 (int)stir_from_system());
864
Darren Tucker8686ed72004-12-20 12:05:08 +1100865 /* try prngd, fall back to commands if prngd fails or not configured */
866 if (seed_from_prngd(buf, bytes) == 0) {
867 RAND_add(buf, bytes, bytes);
868 } else {
869 /* Read in collection commands */
870 if (prng_read_commands(SSH_PRNG_COMMAND_FILE) == -1)
871 fatal("PRNG initialisation failed -- exiting.");
872 debug("Seeded RNG with %i bytes from programs",
873 (int)stir_from_programs());
874 }
Damien Miller7b10ef42002-01-21 23:44:12 +1100875
876#ifdef USE_SEED_FILES
877 prng_write_seedfile();
878#endif
879
880 /*
881 * Write the seed to stdout
882 */
Damien Miller62116dc2001-12-24 01:41:47 +1100883
884 if (!RAND_status())
885 fatal("Not enough entropy in RNG");
886
Damien Millercafbcc72003-03-17 16:13:53 +1100887 if (RAND_bytes(buf, bytes) <= 0)
888 fatal("Couldn't extract entropy from PRNG");
Damien Miller62116dc2001-12-24 01:41:47 +1100889
Damien Miller32e48182002-04-14 19:27:12 +1000890 if (output_hex) {
891 for(ret = 0; ret < bytes; ret++)
892 printf("%02x", (unsigned char)(buf[ret]));
893 printf("\n");
894 } else
Darren Tucker8661b562003-07-06 15:20:46 +1000895 ret = atomicio(vwrite, STDOUT_FILENO, buf, bytes);
Damien Miller787b2ec2003-11-21 23:56:47 +1100896
Damien Miller32e48182002-04-14 19:27:12 +1000897 memset(buf, '\0', bytes);
898 xfree(buf);
Damien Miller787b2ec2003-11-21 23:56:47 +1100899
Damien Miller32e48182002-04-14 19:27:12 +1000900 return ret == bytes ? 0 : 1;
Damien Miller62116dc2001-12-24 01:41:47 +1100901}
Darren Tucker7b48d252005-02-16 13:20:07 +1100902
903/*
904 * We may attempt to re-seed during mkstemp if we are using the one in the
Darren Tucker7a8619a2005-02-16 13:32:30 +1100905 * compat library (via mkstemp -> _gettemp -> arc4random -> seed_rng) so we
906 * need our own seed_rng(). We must also check that we have enough entropy.
Darren Tucker7b48d252005-02-16 13:20:07 +1100907 */
908void
909seed_rng(void)
910{
911 if (!RAND_status())
912 fatal("Not enough entropy in RNG");
913}