blob: bdf73ec4841826270dfb3b6dec5ec57cd21db114 [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 Miller7b10ef42002-01-21 23:44:12 +110053/* Number of bytes we write out */
54#define OUTPUT_SEED_SIZE 48
55
56/* Length of on-disk seedfiles */
57#define SEED_FILE_SIZE 1024
58
59/* Maximum number of command-line arguments to read from file */
60#define NUM_ARGS 10
61
62/* Minimum number of usable commands to be considered sufficient */
63#define MIN_ENTROPY_SOURCES 16
64
65/* Path to on-disk seed file (relative to user's home directory */
66#ifndef SSH_PRNG_SEED_FILE
67# define SSH_PRNG_SEED_FILE _PATH_SSH_USER_DIR"/prng_seed"
68#endif
69
70/* Path to PRNG commands list */
71#ifndef SSH_PRNG_COMMAND_FILE
Damien Miller05eda432002-02-10 18:32:28 +110072# define SSH_PRNG_COMMAND_FILE SSHDIR "/ssh_prng_cmds"
Damien Miller7b10ef42002-01-21 23:44:12 +110073#endif
74
Kevin Steves94435082001-12-25 04:32:58 +000075extern char *__progname;
Kevin Steves94435082001-12-25 04:32:58 +000076
Damien Miller62116dc2001-12-24 01:41:47 +110077#define WHITESPACE " \t\n"
78
79#ifndef RUSAGE_SELF
80# define RUSAGE_SELF 0
81#endif
82#ifndef RUSAGE_CHILDREN
83# define RUSAGE_CHILDREN 0
84#endif
85
Damien Millerc46cc542002-01-22 21:58:27 +110086#if !defined(PRNGD_SOCKET) && !defined(PRNGD_PORT)
Damien Miller7b10ef42002-01-21 23:44:12 +110087# define USE_SEED_FILES
Damien Miller62116dc2001-12-24 01:41:47 +110088#endif
89
Damien Miller7b10ef42002-01-21 23:44:12 +110090typedef struct {
91 /* Proportion of data that is entropy */
92 double rate;
93 /* Counter goes positive if this command times out */
94 unsigned int badness;
95 /* Increases by factor of two each timeout */
96 unsigned int sticky_badness;
97 /* Path to executable */
98 char *path;
99 /* argv to pass to executable */
100 char *args[NUM_ARGS]; /* XXX: arbitrary limit */
101 /* full command string (debug) */
102 char *cmdstring;
103} entropy_cmd_t;
104
105/* slow command timeouts (all in milliseconds) */
106/* static int entropy_timeout_default = ENTROPY_TIMEOUT_MSEC; */
107static int entropy_timeout_current = ENTROPY_TIMEOUT_MSEC;
108
109/* this is initialised from a file, by prng_read_commands() */
110static entropy_cmd_t *entropy_cmds = NULL;
111
112/* Prototypes */
113double stir_from_system(void);
114double stir_from_programs(void);
115double stir_gettimeofday(double entropy_estimate);
116double stir_clock(double entropy_estimate);
117double stir_rusage(int who, double entropy_estimate);
Kevin Steves4bdb5472002-07-28 20:42:23 +0000118double hash_command_output(entropy_cmd_t *src, unsigned char *hash);
Damien Millera8e06ce2003-11-21 23:48:55 +1100119int get_random_bytes_prngd(unsigned char *buf, int len,
Damien Miller7b10ef42002-01-21 23:44:12 +1100120 unsigned short tcp_port, char *socket_path);
121
122/*
123 * Collect 'len' bytes of entropy into 'buf' from PRNGD/EGD daemon
124 * listening either on 'tcp_port', or via Unix domain socket at *
125 * 'socket_path'.
Damien Millera8e06ce2003-11-21 23:48:55 +1100126 * Either a non-zero tcp_port or a non-null socket_path must be
Damien Miller7b10ef42002-01-21 23:44:12 +1100127 * supplied.
128 * Returns 0 on success, -1 on error
129 */
Damien Miller62116dc2001-12-24 01:41:47 +1100130int
Damien Millera8e06ce2003-11-21 23:48:55 +1100131get_random_bytes_prngd(unsigned char *buf, int len,
Damien Miller7b10ef42002-01-21 23:44:12 +1100132 unsigned short tcp_port, char *socket_path)
Damien Miller62116dc2001-12-24 01:41:47 +1100133{
Damien Miller7b10ef42002-01-21 23:44:12 +1100134 int fd, addr_len, rval, errors;
Damien Miller52c8afe2005-06-19 10:19:43 +1000135 u_char msg[2];
Damien Miller7b10ef42002-01-21 23:44:12 +1100136 struct sockaddr_storage addr;
137 struct sockaddr_in *addr_in = (struct sockaddr_in *)&addr;
138 struct sockaddr_un *addr_un = (struct sockaddr_un *)&addr;
Damien Miller62116dc2001-12-24 01:41:47 +1100139 mysig_t old_sigpipe;
140
Damien Miller7b10ef42002-01-21 23:44:12 +1100141 /* Sanity checks */
142 if (socket_path == NULL && tcp_port == 0)
143 fatal("You must specify a port or a socket");
144 if (socket_path != NULL &&
145 strlen(socket_path) >= sizeof(addr_un->sun_path))
146 fatal("Random pool path is too long");
Damien Miller52c8afe2005-06-19 10:19:43 +1000147 if (len <= 0 || len > 255)
148 fatal("Too many bytes (%d) to read from PRNGD", len);
Damien Miller62116dc2001-12-24 01:41:47 +1100149
150 memset(&addr, '\0', sizeof(addr));
151
Damien Miller7b10ef42002-01-21 23:44:12 +1100152 if (tcp_port != 0) {
153 addr_in->sin_family = AF_INET;
154 addr_in->sin_addr.s_addr = htonl(INADDR_LOOPBACK);
155 addr_in->sin_port = htons(tcp_port);
156 addr_len = sizeof(*addr_in);
157 } else {
158 addr_un->sun_family = AF_UNIX;
159 strlcpy(addr_un->sun_path, socket_path,
160 sizeof(addr_un->sun_path));
161 addr_len = offsetof(struct sockaddr_un, sun_path) +
162 strlen(socket_path) + 1;
163 }
Damien Miller62116dc2001-12-24 01:41:47 +1100164
165 old_sigpipe = mysignal(SIGPIPE, SIG_IGN);
166
Damien Miller7b10ef42002-01-21 23:44:12 +1100167 errors = 0;
168 rval = -1;
Damien Miller62116dc2001-12-24 01:41:47 +1100169reopen:
Damien Miller7b10ef42002-01-21 23:44:12 +1100170 fd = socket(addr.ss_family, SOCK_STREAM, 0);
Damien Miller62116dc2001-12-24 01:41:47 +1100171 if (fd == -1) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100172 error("Couldn't create socket: %s", strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100173 goto done;
174 }
Damien Miller62116dc2001-12-24 01:41:47 +1100175
176 if (connect(fd, (struct sockaddr*)&addr, addr_len) == -1) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100177 if (tcp_port != 0) {
178 error("Couldn't connect to PRNGD port %d: %s",
179 tcp_port, strerror(errno));
180 } else {
181 error("Couldn't connect to PRNGD socket \"%s\": %s",
182 addr_un->sun_path, strerror(errno));
183 }
Damien Miller62116dc2001-12-24 01:41:47 +1100184 goto done;
185 }
186
187 /* Send blocking read request to PRNGD */
188 msg[0] = 0x02;
189 msg[1] = len;
190
Darren Tucker8661b562003-07-06 15:20:46 +1000191 if (atomicio(vwrite, fd, msg, sizeof(msg)) != sizeof(msg)) {
Damien Miller62116dc2001-12-24 01:41:47 +1100192 if (errno == EPIPE && errors < 10) {
193 close(fd);
194 errors++;
195 goto reopen;
196 }
197 error("Couldn't write to PRNGD socket: %s",
198 strerror(errno));
199 goto done;
200 }
201
Damien Miller52c8afe2005-06-19 10:19:43 +1000202 if (atomicio(read, fd, buf, len) != (size_t)len) {
Damien Miller62116dc2001-12-24 01:41:47 +1100203 if (errno == EPIPE && errors < 10) {
204 close(fd);
205 errors++;
206 goto reopen;
207 }
208 error("Couldn't read from PRNGD socket: %s",
209 strerror(errno));
210 goto done;
211 }
212
Damien Miller7b10ef42002-01-21 23:44:12 +1100213 rval = 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100214done:
215 mysignal(SIGPIPE, old_sigpipe);
216 if (fd != -1)
217 close(fd);
Damien Miller7b10ef42002-01-21 23:44:12 +1100218 return rval;
Damien Miller62116dc2001-12-24 01:41:47 +1100219}
220
Darren Tucker8686ed72004-12-20 12:05:08 +1100221static int
222seed_from_prngd(unsigned char *buf, size_t bytes)
223{
224#ifdef PRNGD_PORT
225 debug("trying egd/prngd port %d", PRNGD_PORT);
226 if (get_random_bytes_prngd(buf, bytes, PRNGD_PORT, NULL) == 0)
227 return 0;
228#endif
229#ifdef PRNGD_SOCKET
230 debug("trying egd/prngd socket %s", PRNGD_SOCKET);
231 if (get_random_bytes_prngd(buf, bytes, 0, PRNGD_SOCKET) == 0)
232 return 0;
233#endif
234 return -1;
235}
236
Damien Miller62116dc2001-12-24 01:41:47 +1100237double
238stir_gettimeofday(double entropy_estimate)
239{
240 struct timeval tv;
241
242 if (gettimeofday(&tv, NULL) == -1)
243 fatal("Couldn't gettimeofday: %s", strerror(errno));
244
245 RAND_add(&tv, sizeof(tv), entropy_estimate);
246
Damien Miller7b10ef42002-01-21 23:44:12 +1100247 return entropy_estimate;
Damien Miller62116dc2001-12-24 01:41:47 +1100248}
249
250double
251stir_clock(double entropy_estimate)
252{
253#ifdef HAVE_CLOCK
254 clock_t c;
255
256 c = clock();
257 RAND_add(&c, sizeof(c), entropy_estimate);
258
Damien Miller7b10ef42002-01-21 23:44:12 +1100259 return entropy_estimate;
Damien Miller62116dc2001-12-24 01:41:47 +1100260#else /* _HAVE_CLOCK */
Damien Miller7b10ef42002-01-21 23:44:12 +1100261 return 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100262#endif /* _HAVE_CLOCK */
263}
264
265double
266stir_rusage(int who, double entropy_estimate)
267{
268#ifdef HAVE_GETRUSAGE
269 struct rusage ru;
270
271 if (getrusage(who, &ru) == -1)
Damien Miller7b10ef42002-01-21 23:44:12 +1100272 return 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100273
274 RAND_add(&ru, sizeof(ru), entropy_estimate);
275
Damien Miller7b10ef42002-01-21 23:44:12 +1100276 return entropy_estimate;
Damien Miller62116dc2001-12-24 01:41:47 +1100277#else /* _HAVE_GETRUSAGE */
Damien Miller7b10ef42002-01-21 23:44:12 +1100278 return 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100279#endif /* _HAVE_GETRUSAGE */
280}
281
Damien Miller62116dc2001-12-24 01:41:47 +1100282static int
Damien Miller7b10ef42002-01-21 23:44:12 +1100283timeval_diff(struct timeval *t1, struct timeval *t2)
284{
Damien Miller62116dc2001-12-24 01:41:47 +1100285 int secdiff, usecdiff;
286
287 secdiff = t2->tv_sec - t1->tv_sec;
288 usecdiff = (secdiff*1000000) + (t2->tv_usec - t1->tv_usec);
289 return (int)(usecdiff / 1000);
290}
291
292double
Kevin Steves4bdb5472002-07-28 20:42:23 +0000293hash_command_output(entropy_cmd_t *src, unsigned char *hash)
Damien Miller62116dc2001-12-24 01:41:47 +1100294{
Damien Miller7b10ef42002-01-21 23:44:12 +1100295 char buf[8192];
Damien Miller62116dc2001-12-24 01:41:47 +1100296 fd_set rdset;
Damien Miller7b10ef42002-01-21 23:44:12 +1100297 int bytes_read, cmd_eof, error_abort, msec_elapsed, p[2];
298 int status, total_bytes_read;
299 static int devnull = -1;
Damien Miller62116dc2001-12-24 01:41:47 +1100300 pid_t pid;
Damien Miller62116dc2001-12-24 01:41:47 +1100301 SHA_CTX sha;
Damien Miller7b10ef42002-01-21 23:44:12 +1100302 struct timeval tv_start, tv_current;
Damien Miller62116dc2001-12-24 01:41:47 +1100303
304 debug3("Reading output from \'%s\'", src->cmdstring);
305
306 if (devnull == -1) {
307 devnull = open("/dev/null", O_RDWR);
308 if (devnull == -1)
Damien Millera8e06ce2003-11-21 23:48:55 +1100309 fatal("Couldn't open /dev/null: %s",
Damien Miller7b10ef42002-01-21 23:44:12 +1100310 strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100311 }
312
313 if (pipe(p) == -1)
314 fatal("Couldn't open pipe: %s", strerror(errno));
315
316 (void)gettimeofday(&tv_start, NULL); /* record start time */
317
318 switch (pid = fork()) {
319 case -1: /* Error */
320 close(p[0]);
321 close(p[1]);
322 fatal("Couldn't fork: %s", strerror(errno));
323 /* NOTREACHED */
324 case 0: /* Child */
325 dup2(devnull, STDIN_FILENO);
326 dup2(p[1], STDOUT_FILENO);
327 dup2(p[1], STDERR_FILENO);
328 close(p[0]);
329 close(p[1]);
330 close(devnull);
331
332 execv(src->path, (char**)(src->args));
Damien Miller7b10ef42002-01-21 23:44:12 +1100333
Damien Millera8e06ce2003-11-21 23:48:55 +1100334 debug("(child) Couldn't exec '%s': %s",
Damien Miller7b10ef42002-01-21 23:44:12 +1100335 src->cmdstring, strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100336 _exit(-1);
337 default: /* Parent */
338 break;
339 }
340
341 RAND_add(&pid, sizeof(&pid), 0.0);
342
343 close(p[1]);
344
345 /* Hash output from child */
346 SHA1_Init(&sha);
Damien Miller62116dc2001-12-24 01:41:47 +1100347
Damien Miller7b10ef42002-01-21 23:44:12 +1100348 cmd_eof = error_abort = msec_elapsed = total_bytes_read = 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100349 while (!error_abort && !cmd_eof) {
350 int ret;
351 struct timeval tv;
352 int msec_remaining;
353
354 (void) gettimeofday(&tv_current, 0);
Damien Miller7b10ef42002-01-21 23:44:12 +1100355 msec_elapsed = timeval_diff(&tv_start, &tv_current);
Damien Miller62116dc2001-12-24 01:41:47 +1100356 if (msec_elapsed >= entropy_timeout_current) {
357 error_abort=1;
358 continue;
359 }
360 msec_remaining = entropy_timeout_current - msec_elapsed;
361
362 FD_ZERO(&rdset);
363 FD_SET(p[0], &rdset);
Damien Miller7b10ef42002-01-21 23:44:12 +1100364 tv.tv_sec = msec_remaining / 1000;
Damien Miller62116dc2001-12-24 01:41:47 +1100365 tv.tv_usec = (msec_remaining % 1000) * 1000;
366
Damien Miller7b10ef42002-01-21 23:44:12 +1100367 ret = select(p[0] + 1, &rdset, NULL, NULL, &tv);
Damien Miller62116dc2001-12-24 01:41:47 +1100368
369 RAND_add(&tv, sizeof(tv), 0.0);
370
371 switch (ret) {
372 case 0:
373 /* timer expired */
374 error_abort = 1;
Damien Miller5a5da882002-10-21 10:13:35 +1000375 kill(pid, SIGINT);
Damien Miller62116dc2001-12-24 01:41:47 +1100376 break;
377 case 1:
378 /* command input */
379 do {
380 bytes_read = read(p[0], buf, sizeof(buf));
381 } while (bytes_read == -1 && errno == EINTR);
382 RAND_add(&bytes_read, sizeof(&bytes_read), 0.0);
383 if (bytes_read == -1) {
384 error_abort = 1;
385 break;
386 } else if (bytes_read) {
387 SHA1_Update(&sha, buf, bytes_read);
388 total_bytes_read += bytes_read;
389 } else {
390 cmd_eof = 1;
391 }
392 break;
393 case -1:
394 default:
395 /* error */
Damien Millera8e06ce2003-11-21 23:48:55 +1100396 debug("Command '%s': select() failed: %s",
Damien Miller7b10ef42002-01-21 23:44:12 +1100397 src->cmdstring, strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100398 error_abort = 1;
399 break;
400 }
401 }
402
403 SHA1_Final(hash, &sha);
404
405 close(p[0]);
406
407 debug3("Time elapsed: %d msec", msec_elapsed);
408
409 if (waitpid(pid, &status, 0) == -1) {
Damien Millerb6f72f52005-07-17 17:26:43 +1000410 error("Couldn't wait for child '%s' completion: %s",
411 src->cmdstring, strerror(errno));
Damien Miller7b10ef42002-01-21 23:44:12 +1100412 return 0.0;
Damien Miller62116dc2001-12-24 01:41:47 +1100413 }
414
415 RAND_add(&status, sizeof(&status), 0.0);
416
417 if (error_abort) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100418 /*
419 * Closing p[0] on timeout causes the entropy command to
Damien Millera8e06ce2003-11-21 23:48:55 +1100420 * SIGPIPE. Take whatever output we got, and mark this
421 * command as slow
Damien Miller7b10ef42002-01-21 23:44:12 +1100422 */
Damien Miller62116dc2001-12-24 01:41:47 +1100423 debug2("Command '%s' timed out", src->cmdstring);
424 src->sticky_badness *= 2;
425 src->badness = src->sticky_badness;
Damien Miller7b10ef42002-01-21 23:44:12 +1100426 return total_bytes_read;
Damien Miller62116dc2001-12-24 01:41:47 +1100427 }
428
429 if (WIFEXITED(status)) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100430 if (WEXITSTATUS(status) == 0) {
431 return total_bytes_read;
Damien Miller62116dc2001-12-24 01:41:47 +1100432 } else {
Damien Miller7b10ef42002-01-21 23:44:12 +1100433 debug2("Command '%s' exit status was %d",
434 src->cmdstring, WEXITSTATUS(status));
Damien Miller62116dc2001-12-24 01:41:47 +1100435 src->badness = src->sticky_badness = 128;
Damien Miller7b10ef42002-01-21 23:44:12 +1100436 return 0.0;
Damien Miller62116dc2001-12-24 01:41:47 +1100437 }
438 } else if (WIFSIGNALED(status)) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100439 debug2("Command '%s' returned on uncaught signal %d !",
440 src->cmdstring, status);
Damien Miller62116dc2001-12-24 01:41:47 +1100441 src->badness = src->sticky_badness = 128;
Damien Miller7b10ef42002-01-21 23:44:12 +1100442 return 0.0;
Damien Miller62116dc2001-12-24 01:41:47 +1100443 } else
Damien Miller7b10ef42002-01-21 23:44:12 +1100444 return 0.0;
445}
446
447double
448stir_from_system(void)
449{
450 double total_entropy_estimate;
451 long int i;
452
453 total_entropy_estimate = 0;
454
455 i = getpid();
456 RAND_add(&i, sizeof(i), 0.5);
457 total_entropy_estimate += 0.1;
458
459 i = getppid();
460 RAND_add(&i, sizeof(i), 0.5);
461 total_entropy_estimate += 0.1;
462
463 i = getuid();
464 RAND_add(&i, sizeof(i), 0.0);
465 i = getgid();
466 RAND_add(&i, sizeof(i), 0.0);
467
468 total_entropy_estimate += stir_gettimeofday(1.0);
469 total_entropy_estimate += stir_clock(0.5);
470 total_entropy_estimate += stir_rusage(RUSAGE_SELF, 2.0);
471
472 return total_entropy_estimate;
473}
474
475double
476stir_from_programs(void)
477{
478 int c;
479 double entropy, total_entropy;
Kevin Steves4bdb5472002-07-28 20:42:23 +0000480 unsigned char hash[SHA_DIGEST_LENGTH];
Damien Miller7b10ef42002-01-21 23:44:12 +1100481
482 total_entropy = 0;
483 for(c = 0; entropy_cmds[c].path != NULL; c++) {
484 if (!entropy_cmds[c].badness) {
485 /* Hash output from command */
486 entropy = hash_command_output(&entropy_cmds[c],
487 hash);
488
489 /* Scale back estimate by command's rate */
490 entropy *= entropy_cmds[c].rate;
491
492 /* Upper bound of entropy is SHA_DIGEST_LENGTH */
493 if (entropy > SHA_DIGEST_LENGTH)
494 entropy = SHA_DIGEST_LENGTH;
495
496 /* Stir it in */
497 RAND_add(hash, sizeof(hash), entropy);
498
Damien Millera8e06ce2003-11-21 23:48:55 +1100499 debug3("Got %0.2f bytes of entropy from '%s'",
Damien Miller7b10ef42002-01-21 23:44:12 +1100500 entropy, entropy_cmds[c].cmdstring);
501
502 total_entropy += entropy;
503
504 /* Execution time should be a bit unpredictable */
505 total_entropy += stir_gettimeofday(0.05);
506 total_entropy += stir_clock(0.05);
507 total_entropy += stir_rusage(RUSAGE_SELF, 0.1);
508 total_entropy += stir_rusage(RUSAGE_CHILDREN, 0.1);
509 } else {
510 debug2("Command '%s' disabled (badness %d)",
Damien Millera8e06ce2003-11-21 23:48:55 +1100511 entropy_cmds[c].cmdstring,
Damien Miller7b10ef42002-01-21 23:44:12 +1100512 entropy_cmds[c].badness);
513
514 if (entropy_cmds[c].badness > 0)
515 entropy_cmds[c].badness--;
516 }
517 }
518
519 return total_entropy;
Damien Miller62116dc2001-12-24 01:41:47 +1100520}
521
522/*
523 * prng seedfile functions
524 */
525int
Damien Miller7b10ef42002-01-21 23:44:12 +1100526prng_check_seedfile(char *filename)
527{
Damien Miller62116dc2001-12-24 01:41:47 +1100528 struct stat st;
529
Damien Miller7b10ef42002-01-21 23:44:12 +1100530 /*
Damien Millera8e06ce2003-11-21 23:48:55 +1100531 * XXX raceable: eg replace seed between this stat and subsequent
532 * open. Not such a problem because we don't really trust the
Damien Miller7b10ef42002-01-21 23:44:12 +1100533 * seed file anyway.
534 * XXX: use secure path checking as elsewhere in OpenSSH
535 */
Damien Miller62116dc2001-12-24 01:41:47 +1100536 if (lstat(filename, &st) == -1) {
537 /* Give up on hard errors */
538 if (errno != ENOENT)
Damien Miller7b10ef42002-01-21 23:44:12 +1100539 debug("WARNING: Couldn't stat random seed file "
540 "\"%.100s\": %s", filename, strerror(errno));
541 return 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100542 }
543
544 /* regular file? */
545 if (!S_ISREG(st.st_mode))
Damien Miller7b10ef42002-01-21 23:44:12 +1100546 fatal("PRNG seedfile %.100s is not a regular file",
547 filename);
Damien Miller62116dc2001-12-24 01:41:47 +1100548
549 /* mode 0600, owned by root or the current user? */
550 if (((st.st_mode & 0177) != 0) || !(st.st_uid == getuid())) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100551 debug("WARNING: PRNG seedfile %.100s must be mode 0600, "
Damien Millerc46b6bc2003-05-16 15:51:44 +1000552 "owned by uid %li", filename, (long int)getuid());
Damien Miller7b10ef42002-01-21 23:44:12 +1100553 return 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100554 }
555
Damien Miller7b10ef42002-01-21 23:44:12 +1100556 return 1;
Damien Miller62116dc2001-12-24 01:41:47 +1100557}
558
559void
Damien Miller7b10ef42002-01-21 23:44:12 +1100560prng_write_seedfile(void)
561{
Damien Millered462d92005-02-16 13:02:45 +1100562 int fd, save_errno;
Kevin Steves4bdb5472002-07-28 20:42:23 +0000563 unsigned char seed[SEED_FILE_SIZE];
Damien Millered462d92005-02-16 13:02:45 +1100564 char filename[MAXPATHLEN], tmpseed[MAXPATHLEN];
Damien Miller62116dc2001-12-24 01:41:47 +1100565 struct passwd *pw;
Damien Millered462d92005-02-16 13:02:45 +1100566 mode_t old_umask;
Damien Miller62116dc2001-12-24 01:41:47 +1100567
568 pw = getpwuid(getuid());
569 if (pw == NULL)
Damien Miller7b10ef42002-01-21 23:44:12 +1100570 fatal("Couldn't get password entry for current user "
Damien Millerc46b6bc2003-05-16 15:51:44 +1000571 "(%li): %s", (long int)getuid(), strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100572
573 /* Try to ensure that the parent directory is there */
574 snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir,
Damien Miller7b10ef42002-01-21 23:44:12 +1100575 _PATH_SSH_USER_DIR);
Damien Miller62116dc2001-12-24 01:41:47 +1100576 mkdir(filename, 0700);
577
578 snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir,
Damien Miller7b10ef42002-01-21 23:44:12 +1100579 SSH_PRNG_SEED_FILE);
Damien Miller62116dc2001-12-24 01:41:47 +1100580
Damien Millered462d92005-02-16 13:02:45 +1100581 strlcpy(tmpseed, filename, sizeof(tmpseed));
582 if (strlcat(tmpseed, ".XXXXXXXXXX", sizeof(tmpseed)) >=
583 sizeof(tmpseed))
584 fatal("PRNG seed filename too long");
Damien Miller62116dc2001-12-24 01:41:47 +1100585
Damien Millercafbcc72003-03-17 16:13:53 +1100586 if (RAND_bytes(seed, sizeof(seed)) <= 0)
Ben Lindstromda4d9cf2003-09-22 15:36:15 +0000587 fatal("PRNG seed extraction failed");
Damien Miller62116dc2001-12-24 01:41:47 +1100588
589 /* Don't care if the seed doesn't exist */
590 prng_check_seedfile(filename);
591
Damien Millered462d92005-02-16 13:02:45 +1100592 old_umask = umask(0177);
593
594 if ((fd = mkstemp(tmpseed)) == -1) {
595 debug("WARNING: couldn't make temporary PRNG seedfile %.100s "
596 "(%.100s)", tmpseed, strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100597 } else {
Damien Millered462d92005-02-16 13:02:45 +1100598 debug("writing PRNG seed to file %.100s", tmpseed);
599 if (atomicio(vwrite, fd, &seed, sizeof(seed)) < sizeof(seed)) {
600 save_errno = errno;
601 close(fd);
602 unlink(tmpseed);
Damien Miller7b10ef42002-01-21 23:44:12 +1100603 fatal("problem writing PRNG seedfile %.100s "
Damien Millered462d92005-02-16 13:02:45 +1100604 "(%.100s)", filename, strerror(save_errno));
605 }
Damien Miller62116dc2001-12-24 01:41:47 +1100606 close(fd);
Damien Millered462d92005-02-16 13:02:45 +1100607 debug("moving temporary PRNG seed to file %.100s", filename);
608 if (rename(tmpseed, filename) == -1) {
609 save_errno = errno;
610 unlink(tmpseed);
611 fatal("problem renaming PRNG seedfile from %.100s "
Damien Miller94cf4c82005-07-17 17:04:47 +1000612 "to %.100s (%.100s)", tmpseed, filename,
Damien Millered462d92005-02-16 13:02:45 +1100613 strerror(save_errno));
614 }
Damien Miller62116dc2001-12-24 01:41:47 +1100615 }
Damien Millered462d92005-02-16 13:02:45 +1100616 umask(old_umask);
Damien Miller62116dc2001-12-24 01:41:47 +1100617}
618
619void
Damien Miller7b10ef42002-01-21 23:44:12 +1100620prng_read_seedfile(void)
621{
Damien Miller62116dc2001-12-24 01:41:47 +1100622 int fd;
Damien Miller7b10ef42002-01-21 23:44:12 +1100623 char seed[SEED_FILE_SIZE], filename[MAXPATHLEN];
Damien Miller62116dc2001-12-24 01:41:47 +1100624 struct passwd *pw;
625
626 pw = getpwuid(getuid());
627 if (pw == NULL)
Damien Miller7b10ef42002-01-21 23:44:12 +1100628 fatal("Couldn't get password entry for current user "
Damien Millerc46b6bc2003-05-16 15:51:44 +1000629 "(%li): %s", (long int)getuid(), strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100630
631 snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir,
632 SSH_PRNG_SEED_FILE);
633
634 debug("loading PRNG seed from file %.100s", filename);
635
636 if (!prng_check_seedfile(filename)) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100637 verbose("Random seed file not found or invalid, ignoring.");
Damien Miller62116dc2001-12-24 01:41:47 +1100638 return;
639 }
640
641 /* open the file and read in the seed */
642 fd = open(filename, O_RDONLY);
643 if (fd == -1)
Damien Miller7b10ef42002-01-21 23:44:12 +1100644 fatal("could not open PRNG seedfile %.100s (%.100s)",
645 filename, strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100646
Damien Miller7b10ef42002-01-21 23:44:12 +1100647 if (atomicio(read, fd, &seed, sizeof(seed)) < sizeof(seed)) {
648 verbose("invalid or short read from PRNG seedfile "
649 "%.100s - ignoring", filename);
Damien Miller62116dc2001-12-24 01:41:47 +1100650 memset(seed, '\0', sizeof(seed));
651 }
652 close(fd);
653
654 /* stir in the seed, with estimated entropy zero */
655 RAND_add(&seed, sizeof(seed), 0.0);
656}
657
658
659/*
660 * entropy command initialisation functions
661 */
662int
663prng_read_commands(char *cmdfilename)
664{
Damien Miller7b10ef42002-01-21 23:44:12 +1100665 char cmd[SEED_FILE_SIZE], *cp, line[1024], path[SEED_FILE_SIZE];
Damien Miller62116dc2001-12-24 01:41:47 +1100666 double est;
Damien Miller7b10ef42002-01-21 23:44:12 +1100667 entropy_cmd_t *entcmd;
668 FILE *f;
669 int cur_cmd, linenum, num_cmds, arg;
Damien Miller62116dc2001-12-24 01:41:47 +1100670
Damien Miller7b10ef42002-01-21 23:44:12 +1100671 if ((f = fopen(cmdfilename, "r")) == NULL) {
Damien Miller62116dc2001-12-24 01:41:47 +1100672 fatal("couldn't read entropy commands file %.100s: %.100s",
673 cmdfilename, strerror(errno));
674 }
675
Damien Miller7b10ef42002-01-21 23:44:12 +1100676 num_cmds = 64;
677 entcmd = xmalloc(num_cmds * sizeof(entropy_cmd_t));
678 memset(entcmd, '\0', num_cmds * sizeof(entropy_cmd_t));
Damien Miller62116dc2001-12-24 01:41:47 +1100679
680 /* Read in file */
Damien Miller7b10ef42002-01-21 23:44:12 +1100681 cur_cmd = linenum = 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100682 while (fgets(line, sizeof(line), f)) {
Damien Miller62116dc2001-12-24 01:41:47 +1100683 linenum++;
684
Damien Miller7b10ef42002-01-21 23:44:12 +1100685 /* Skip leading whitespace, blank lines and comments */
Damien Miller62116dc2001-12-24 01:41:47 +1100686 cp = line + strspn(line, WHITESPACE);
687 if ((*cp == 0) || (*cp == '#'))
688 continue; /* done with this line */
689
Damien Miller7b10ef42002-01-21 23:44:12 +1100690 /*
Damien Millera8e06ce2003-11-21 23:48:55 +1100691 * The first non-whitespace char should be a double quote
Damien Miller7b10ef42002-01-21 23:44:12 +1100692 * delimiting the commandline
693 */
Damien Miller62116dc2001-12-24 01:41:47 +1100694 if (*cp != '"') {
Damien Miller7b10ef42002-01-21 23:44:12 +1100695 error("bad entropy command, %.100s line %d",
696 cmdfilename, linenum);
Damien Miller62116dc2001-12-24 01:41:47 +1100697 continue;
698 }
699
Damien Miller7b10ef42002-01-21 23:44:12 +1100700 /*
701 * First token, command args (incl. argv[0]) in double
702 * quotes
703 */
Damien Miller62116dc2001-12-24 01:41:47 +1100704 cp = strtok(cp, "\"");
705 if (cp == NULL) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100706 error("missing or bad command string, %.100s "
707 "line %d -- ignored", cmdfilename, linenum);
Damien Miller62116dc2001-12-24 01:41:47 +1100708 continue;
709 }
710 strlcpy(cmd, cp, sizeof(cmd));
711
Damien Miller7b10ef42002-01-21 23:44:12 +1100712 /* Second token, full command path */
Damien Miller62116dc2001-12-24 01:41:47 +1100713 if ((cp = strtok(NULL, WHITESPACE)) == NULL) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100714 error("missing command path, %.100s "
715 "line %d -- ignored", cmdfilename, linenum);
Damien Miller62116dc2001-12-24 01:41:47 +1100716 continue;
717 }
718
Damien Miller7b10ef42002-01-21 23:44:12 +1100719 /* Did configure mark this as dead? */
Damien Miller62116dc2001-12-24 01:41:47 +1100720 if (strncmp("undef", cp, 5) == 0)
721 continue;
722
723 strlcpy(path, cp, sizeof(path));
724
Damien Miller7b10ef42002-01-21 23:44:12 +1100725 /* Third token, entropy rate estimate for this command */
Damien Miller62116dc2001-12-24 01:41:47 +1100726 if ((cp = strtok(NULL, WHITESPACE)) == NULL) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100727 error("missing entropy estimate, %.100s "
728 "line %d -- ignored", cmdfilename, linenum);
Damien Miller62116dc2001-12-24 01:41:47 +1100729 continue;
730 }
Damien Miller7b10ef42002-01-21 23:44:12 +1100731 est = strtod(cp, NULL);
Damien Miller62116dc2001-12-24 01:41:47 +1100732
733 /* end of line */
734 if ((cp = strtok(NULL, WHITESPACE)) != NULL) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100735 error("garbage at end of line %d in %.100s "
736 "-- ignored", linenum, cmdfilename);
Damien Miller62116dc2001-12-24 01:41:47 +1100737 continue;
738 }
739
740 /* save the command for debug messages */
741 entcmd[cur_cmd].cmdstring = xstrdup(cmd);
742
743 /* split the command args */
744 cp = strtok(cmd, WHITESPACE);
745 arg = 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100746 do {
Damien Miller7b10ef42002-01-21 23:44:12 +1100747 entcmd[cur_cmd].args[arg] = xstrdup(cp);
Damien Miller62116dc2001-12-24 01:41:47 +1100748 arg++;
Damien Miller7b10ef42002-01-21 23:44:12 +1100749 } while(arg < NUM_ARGS && (cp = strtok(NULL, WHITESPACE)));
Damien Miller62116dc2001-12-24 01:41:47 +1100750
751 if (strtok(NULL, WHITESPACE))
Damien Miller7b10ef42002-01-21 23:44:12 +1100752 error("ignored extra commands (max %d), %.100s "
753 "line %d", NUM_ARGS, cmdfilename, linenum);
Damien Miller62116dc2001-12-24 01:41:47 +1100754
755 /* Copy the command path and rate estimate */
756 entcmd[cur_cmd].path = xstrdup(path);
757 entcmd[cur_cmd].rate = est;
758
759 /* Initialise other values */
760 entcmd[cur_cmd].sticky_badness = 1;
761
762 cur_cmd++;
763
Damien Miller7b10ef42002-01-21 23:44:12 +1100764 /*
765 * If we've filled the array, reallocate it twice the size
Damien Millera8e06ce2003-11-21 23:48:55 +1100766 * Do this now because even if this we're on the last
Damien Miller7b10ef42002-01-21 23:44:12 +1100767 * command we need another slot to mark the last entry
768 */
Damien Miller62116dc2001-12-24 01:41:47 +1100769 if (cur_cmd == num_cmds) {
770 num_cmds *= 2;
Damien Miller7b10ef42002-01-21 23:44:12 +1100771 entcmd = xrealloc(entcmd, num_cmds *
772 sizeof(entropy_cmd_t));
Damien Miller62116dc2001-12-24 01:41:47 +1100773 }
774 }
775
776 /* zero the last entry */
Damien Miller7b10ef42002-01-21 23:44:12 +1100777 memset(&entcmd[cur_cmd], '\0', sizeof(entropy_cmd_t));
Damien Miller62116dc2001-12-24 01:41:47 +1100778
779 /* trim to size */
Damien Miller7b10ef42002-01-21 23:44:12 +1100780 entropy_cmds = xrealloc(entcmd, (cur_cmd + 1) *
781 sizeof(entropy_cmd_t));
Damien Miller62116dc2001-12-24 01:41:47 +1100782
Damien Miller7b10ef42002-01-21 23:44:12 +1100783 debug("Loaded %d entropy commands from %.100s", cur_cmd,
784 cmdfilename);
Damien Miller62116dc2001-12-24 01:41:47 +1100785
Damien Miller7b10ef42002-01-21 23:44:12 +1100786 return cur_cmd < MIN_ENTROPY_SOURCES ? -1 : 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100787}
788
Damien Miller32e48182002-04-14 19:27:12 +1000789void
790usage(void)
791{
792 fprintf(stderr, "Usage: %s [options]\n", __progname);
793 fprintf(stderr, " -v Verbose; display verbose debugging messages.\n");
794 fprintf(stderr, " Multiple -v increases verbosity.\n");
Damien Miller7daf0442004-08-23 21:52:08 +1000795 fprintf(stderr, " -x Force output in hexadecimal (for debugging)\n");
Damien Miller32e48182002-04-14 19:27:12 +1000796 fprintf(stderr, " -X Force output in binary\n");
797 fprintf(stderr, " -b bytes Number of bytes to output (default %d)\n",
798 OUTPUT_SEED_SIZE);
799}
800
Damien Millera8e06ce2003-11-21 23:48:55 +1100801int
Damien Miller62116dc2001-12-24 01:41:47 +1100802main(int argc, char **argv)
803{
Damien Miller32e48182002-04-14 19:27:12 +1000804 unsigned char *buf;
805 int ret, ch, debug_level, output_hex, bytes;
806 extern char *optarg;
807 LogLevel ll;
Damien Miller62116dc2001-12-24 01:41:47 +1100808
Damien Miller59d3d5b2003-08-22 09:34:41 +1000809 __progname = ssh_get_progname(argv[0]);
Damien Miller62116dc2001-12-24 01:41:47 +1100810 log_init(argv[0], SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_USER, 1);
811
Damien Miller32e48182002-04-14 19:27:12 +1000812 ll = SYSLOG_LEVEL_INFO;
813 debug_level = output_hex = 0;
814 bytes = OUTPUT_SEED_SIZE;
815
816 /* Don't write binary data to a tty, unless we are forced to */
817 if (isatty(STDOUT_FILENO))
818 output_hex = 1;
Damien Miller787b2ec2003-11-21 23:56:47 +1100819
Damien Miller32e48182002-04-14 19:27:12 +1000820 while ((ch = getopt(argc, argv, "vxXhb:")) != -1) {
821 switch (ch) {
822 case 'v':
823 if (debug_level < 3)
824 ll = SYSLOG_LEVEL_DEBUG1 + debug_level++;
825 break;
826 case 'x':
827 output_hex = 1;
828 break;
829 case 'X':
830 output_hex = 0;
831 break;
832 case 'b':
833 if ((bytes = atoi(optarg)) <= 0)
834 fatal("Invalid number of output bytes");
835 break;
836 case 'h':
837 usage();
838 exit(0);
839 default:
840 error("Invalid commandline option");
841 usage();
842 }
843 }
844
845 log_init(argv[0], ll, SYSLOG_FACILITY_USER, 1);
Damien Miller787b2ec2003-11-21 23:56:47 +1100846
Damien Miller7b10ef42002-01-21 23:44:12 +1100847#ifdef USE_SEED_FILES
848 prng_read_seedfile();
849#endif
850
Damien Miller32e48182002-04-14 19:27:12 +1000851 buf = xmalloc(bytes);
852
Damien Miller7b10ef42002-01-21 23:44:12 +1100853 /*
854 * Seed the RNG from wherever we can
855 */
Damien Miller787b2ec2003-11-21 23:56:47 +1100856
Damien Miller7b10ef42002-01-21 23:44:12 +1100857 /* Take whatever is on the stack, but don't credit it */
Damien Miller32e48182002-04-14 19:27:12 +1000858 RAND_add(buf, bytes, 0);
Damien Miller7b10ef42002-01-21 23:44:12 +1100859
Damien Millera8e06ce2003-11-21 23:48:55 +1100860 debug("Seeded RNG with %i bytes from system calls",
Damien Miller7b10ef42002-01-21 23:44:12 +1100861 (int)stir_from_system());
862
Darren Tucker8686ed72004-12-20 12:05:08 +1100863 /* try prngd, fall back to commands if prngd fails or not configured */
864 if (seed_from_prngd(buf, bytes) == 0) {
865 RAND_add(buf, bytes, bytes);
866 } else {
867 /* Read in collection commands */
868 if (prng_read_commands(SSH_PRNG_COMMAND_FILE) == -1)
869 fatal("PRNG initialisation failed -- exiting.");
870 debug("Seeded RNG with %i bytes from programs",
871 (int)stir_from_programs());
872 }
Damien Miller7b10ef42002-01-21 23:44:12 +1100873
874#ifdef USE_SEED_FILES
875 prng_write_seedfile();
876#endif
877
878 /*
879 * Write the seed to stdout
880 */
Damien Miller62116dc2001-12-24 01:41:47 +1100881
882 if (!RAND_status())
883 fatal("Not enough entropy in RNG");
884
Damien Millercafbcc72003-03-17 16:13:53 +1100885 if (RAND_bytes(buf, bytes) <= 0)
886 fatal("Couldn't extract entropy from PRNG");
Damien Miller62116dc2001-12-24 01:41:47 +1100887
Damien Miller32e48182002-04-14 19:27:12 +1000888 if (output_hex) {
889 for(ret = 0; ret < bytes; ret++)
890 printf("%02x", (unsigned char)(buf[ret]));
891 printf("\n");
892 } else
Darren Tucker8661b562003-07-06 15:20:46 +1000893 ret = atomicio(vwrite, STDOUT_FILENO, buf, bytes);
Damien Miller787b2ec2003-11-21 23:56:47 +1100894
Damien Miller32e48182002-04-14 19:27:12 +1000895 memset(buf, '\0', bytes);
896 xfree(buf);
Damien Miller787b2ec2003-11-21 23:56:47 +1100897
Damien Miller32e48182002-04-14 19:27:12 +1000898 return ret == bytes ? 0 : 1;
Damien Miller62116dc2001-12-24 01:41:47 +1100899}
Darren Tucker7b48d252005-02-16 13:20:07 +1100900
901/*
902 * We may attempt to re-seed during mkstemp if we are using the one in the
Darren Tucker7a8619a2005-02-16 13:32:30 +1100903 * compat library (via mkstemp -> _gettemp -> arc4random -> seed_rng) so we
904 * need our own seed_rng(). We must also check that we have enough entropy.
Darren Tucker7b48d252005-02-16 13:20:07 +1100905 */
906void
907seed_rng(void)
908{
909 if (!RAND_status())
910 fatal("Not enough entropy in RNG");
911}