blob: d7d8d0f3b268dca157b7b53c90d30ebdb9916ea8 [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
27#include <openssl/rand.h>
28#include <openssl/sha.h>
29#include <openssl/crypto.h>
30
31/* SunOS 4.4.4 needs this */
32#ifdef HAVE_FLOATINGPOINT_H
33# include <floatingpoint.h>
34#endif /* HAVE_FLOATINGPOINT_H */
35
36#include "misc.h"
37#include "xmalloc.h"
38#include "atomicio.h"
39#include "pathnames.h"
40#include "log.h"
41
Darren Tucker7a8619a2005-02-16 13:32:30 +110042RCSID("$Id: ssh-rand-helper.c,v 1.23 2005/02/16 02:32:30 dtucker Exp $");
Damien Miller7b10ef42002-01-21 23:44:12 +110043
44/* Number of bytes we write out */
45#define OUTPUT_SEED_SIZE 48
46
47/* Length of on-disk seedfiles */
48#define SEED_FILE_SIZE 1024
49
50/* Maximum number of command-line arguments to read from file */
51#define NUM_ARGS 10
52
53/* Minimum number of usable commands to be considered sufficient */
54#define MIN_ENTROPY_SOURCES 16
55
56/* Path to on-disk seed file (relative to user's home directory */
57#ifndef SSH_PRNG_SEED_FILE
58# define SSH_PRNG_SEED_FILE _PATH_SSH_USER_DIR"/prng_seed"
59#endif
60
61/* Path to PRNG commands list */
62#ifndef SSH_PRNG_COMMAND_FILE
Damien Miller05eda432002-02-10 18:32:28 +110063# define SSH_PRNG_COMMAND_FILE SSHDIR "/ssh_prng_cmds"
Damien Miller7b10ef42002-01-21 23:44:12 +110064#endif
65
Kevin Steves94435082001-12-25 04:32:58 +000066extern char *__progname;
Kevin Steves94435082001-12-25 04:32:58 +000067
Damien Miller62116dc2001-12-24 01:41:47 +110068#define WHITESPACE " \t\n"
69
70#ifndef RUSAGE_SELF
71# define RUSAGE_SELF 0
72#endif
73#ifndef RUSAGE_CHILDREN
74# define RUSAGE_CHILDREN 0
75#endif
76
Damien Millerc46cc542002-01-22 21:58:27 +110077#if !defined(PRNGD_SOCKET) && !defined(PRNGD_PORT)
Damien Miller7b10ef42002-01-21 23:44:12 +110078# define USE_SEED_FILES
Damien Miller62116dc2001-12-24 01:41:47 +110079#endif
80
Damien Miller7b10ef42002-01-21 23:44:12 +110081typedef struct {
82 /* Proportion of data that is entropy */
83 double rate;
84 /* Counter goes positive if this command times out */
85 unsigned int badness;
86 /* Increases by factor of two each timeout */
87 unsigned int sticky_badness;
88 /* Path to executable */
89 char *path;
90 /* argv to pass to executable */
91 char *args[NUM_ARGS]; /* XXX: arbitrary limit */
92 /* full command string (debug) */
93 char *cmdstring;
94} entropy_cmd_t;
95
96/* slow command timeouts (all in milliseconds) */
97/* static int entropy_timeout_default = ENTROPY_TIMEOUT_MSEC; */
98static int entropy_timeout_current = ENTROPY_TIMEOUT_MSEC;
99
100/* this is initialised from a file, by prng_read_commands() */
101static entropy_cmd_t *entropy_cmds = NULL;
102
103/* Prototypes */
104double stir_from_system(void);
105double stir_from_programs(void);
106double stir_gettimeofday(double entropy_estimate);
107double stir_clock(double entropy_estimate);
108double stir_rusage(int who, double entropy_estimate);
Kevin Steves4bdb5472002-07-28 20:42:23 +0000109double hash_command_output(entropy_cmd_t *src, unsigned char *hash);
Damien Millera8e06ce2003-11-21 23:48:55 +1100110int get_random_bytes_prngd(unsigned char *buf, int len,
Damien Miller7b10ef42002-01-21 23:44:12 +1100111 unsigned short tcp_port, char *socket_path);
112
113/*
114 * Collect 'len' bytes of entropy into 'buf' from PRNGD/EGD daemon
115 * listening either on 'tcp_port', or via Unix domain socket at *
116 * 'socket_path'.
Damien Millera8e06ce2003-11-21 23:48:55 +1100117 * Either a non-zero tcp_port or a non-null socket_path must be
Damien Miller7b10ef42002-01-21 23:44:12 +1100118 * supplied.
119 * Returns 0 on success, -1 on error
120 */
Damien Miller62116dc2001-12-24 01:41:47 +1100121int
Damien Millera8e06ce2003-11-21 23:48:55 +1100122get_random_bytes_prngd(unsigned char *buf, int len,
Damien Miller7b10ef42002-01-21 23:44:12 +1100123 unsigned short tcp_port, char *socket_path)
Damien Miller62116dc2001-12-24 01:41:47 +1100124{
Damien Miller7b10ef42002-01-21 23:44:12 +1100125 int fd, addr_len, rval, errors;
Damien Miller62116dc2001-12-24 01:41:47 +1100126 char msg[2];
Damien Miller7b10ef42002-01-21 23:44:12 +1100127 struct sockaddr_storage addr;
128 struct sockaddr_in *addr_in = (struct sockaddr_in *)&addr;
129 struct sockaddr_un *addr_un = (struct sockaddr_un *)&addr;
Damien Miller62116dc2001-12-24 01:41:47 +1100130 mysig_t old_sigpipe;
131
Damien Miller7b10ef42002-01-21 23:44:12 +1100132 /* Sanity checks */
133 if (socket_path == NULL && tcp_port == 0)
134 fatal("You must specify a port or a socket");
135 if (socket_path != NULL &&
136 strlen(socket_path) >= sizeof(addr_un->sun_path))
137 fatal("Random pool path is too long");
Damien Miller62116dc2001-12-24 01:41:47 +1100138 if (len > 255)
139 fatal("Too many bytes to read from PRNGD");
140
141 memset(&addr, '\0', sizeof(addr));
142
Damien Miller7b10ef42002-01-21 23:44:12 +1100143 if (tcp_port != 0) {
144 addr_in->sin_family = AF_INET;
145 addr_in->sin_addr.s_addr = htonl(INADDR_LOOPBACK);
146 addr_in->sin_port = htons(tcp_port);
147 addr_len = sizeof(*addr_in);
148 } else {
149 addr_un->sun_family = AF_UNIX;
150 strlcpy(addr_un->sun_path, socket_path,
151 sizeof(addr_un->sun_path));
152 addr_len = offsetof(struct sockaddr_un, sun_path) +
153 strlen(socket_path) + 1;
154 }
Damien Miller62116dc2001-12-24 01:41:47 +1100155
156 old_sigpipe = mysignal(SIGPIPE, SIG_IGN);
157
Damien Miller7b10ef42002-01-21 23:44:12 +1100158 errors = 0;
159 rval = -1;
Damien Miller62116dc2001-12-24 01:41:47 +1100160reopen:
Damien Miller7b10ef42002-01-21 23:44:12 +1100161 fd = socket(addr.ss_family, SOCK_STREAM, 0);
Damien Miller62116dc2001-12-24 01:41:47 +1100162 if (fd == -1) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100163 error("Couldn't create socket: %s", strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100164 goto done;
165 }
Damien Miller62116dc2001-12-24 01:41:47 +1100166
167 if (connect(fd, (struct sockaddr*)&addr, addr_len) == -1) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100168 if (tcp_port != 0) {
169 error("Couldn't connect to PRNGD port %d: %s",
170 tcp_port, strerror(errno));
171 } else {
172 error("Couldn't connect to PRNGD socket \"%s\": %s",
173 addr_un->sun_path, strerror(errno));
174 }
Damien Miller62116dc2001-12-24 01:41:47 +1100175 goto done;
176 }
177
178 /* Send blocking read request to PRNGD */
179 msg[0] = 0x02;
180 msg[1] = len;
181
Darren Tucker8661b562003-07-06 15:20:46 +1000182 if (atomicio(vwrite, fd, msg, sizeof(msg)) != sizeof(msg)) {
Damien Miller62116dc2001-12-24 01:41:47 +1100183 if (errno == EPIPE && errors < 10) {
184 close(fd);
185 errors++;
186 goto reopen;
187 }
188 error("Couldn't write to PRNGD socket: %s",
189 strerror(errno));
190 goto done;
191 }
192
193 if (atomicio(read, fd, buf, len) != len) {
194 if (errno == EPIPE && errors < 10) {
195 close(fd);
196 errors++;
197 goto reopen;
198 }
199 error("Couldn't read from PRNGD socket: %s",
200 strerror(errno));
201 goto done;
202 }
203
Damien Miller7b10ef42002-01-21 23:44:12 +1100204 rval = 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100205done:
206 mysignal(SIGPIPE, old_sigpipe);
207 if (fd != -1)
208 close(fd);
Damien Miller7b10ef42002-01-21 23:44:12 +1100209 return rval;
Damien Miller62116dc2001-12-24 01:41:47 +1100210}
211
Darren Tucker8686ed72004-12-20 12:05:08 +1100212static int
213seed_from_prngd(unsigned char *buf, size_t bytes)
214{
215#ifdef PRNGD_PORT
216 debug("trying egd/prngd port %d", PRNGD_PORT);
217 if (get_random_bytes_prngd(buf, bytes, PRNGD_PORT, NULL) == 0)
218 return 0;
219#endif
220#ifdef PRNGD_SOCKET
221 debug("trying egd/prngd socket %s", PRNGD_SOCKET);
222 if (get_random_bytes_prngd(buf, bytes, 0, PRNGD_SOCKET) == 0)
223 return 0;
224#endif
225 return -1;
226}
227
Damien Miller62116dc2001-12-24 01:41:47 +1100228double
229stir_gettimeofday(double entropy_estimate)
230{
231 struct timeval tv;
232
233 if (gettimeofday(&tv, NULL) == -1)
234 fatal("Couldn't gettimeofday: %s", strerror(errno));
235
236 RAND_add(&tv, sizeof(tv), entropy_estimate);
237
Damien Miller7b10ef42002-01-21 23:44:12 +1100238 return entropy_estimate;
Damien Miller62116dc2001-12-24 01:41:47 +1100239}
240
241double
242stir_clock(double entropy_estimate)
243{
244#ifdef HAVE_CLOCK
245 clock_t c;
246
247 c = clock();
248 RAND_add(&c, sizeof(c), entropy_estimate);
249
Damien Miller7b10ef42002-01-21 23:44:12 +1100250 return entropy_estimate;
Damien Miller62116dc2001-12-24 01:41:47 +1100251#else /* _HAVE_CLOCK */
Damien Miller7b10ef42002-01-21 23:44:12 +1100252 return 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100253#endif /* _HAVE_CLOCK */
254}
255
256double
257stir_rusage(int who, double entropy_estimate)
258{
259#ifdef HAVE_GETRUSAGE
260 struct rusage ru;
261
262 if (getrusage(who, &ru) == -1)
Damien Miller7b10ef42002-01-21 23:44:12 +1100263 return 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100264
265 RAND_add(&ru, sizeof(ru), entropy_estimate);
266
Damien Miller7b10ef42002-01-21 23:44:12 +1100267 return entropy_estimate;
Damien Miller62116dc2001-12-24 01:41:47 +1100268#else /* _HAVE_GETRUSAGE */
Damien Miller7b10ef42002-01-21 23:44:12 +1100269 return 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100270#endif /* _HAVE_GETRUSAGE */
271}
272
Damien Miller62116dc2001-12-24 01:41:47 +1100273static int
Damien Miller7b10ef42002-01-21 23:44:12 +1100274timeval_diff(struct timeval *t1, struct timeval *t2)
275{
Damien Miller62116dc2001-12-24 01:41:47 +1100276 int secdiff, usecdiff;
277
278 secdiff = t2->tv_sec - t1->tv_sec;
279 usecdiff = (secdiff*1000000) + (t2->tv_usec - t1->tv_usec);
280 return (int)(usecdiff / 1000);
281}
282
283double
Kevin Steves4bdb5472002-07-28 20:42:23 +0000284hash_command_output(entropy_cmd_t *src, unsigned char *hash)
Damien Miller62116dc2001-12-24 01:41:47 +1100285{
Damien Miller7b10ef42002-01-21 23:44:12 +1100286 char buf[8192];
Damien Miller62116dc2001-12-24 01:41:47 +1100287 fd_set rdset;
Damien Miller7b10ef42002-01-21 23:44:12 +1100288 int bytes_read, cmd_eof, error_abort, msec_elapsed, p[2];
289 int status, total_bytes_read;
290 static int devnull = -1;
Damien Miller62116dc2001-12-24 01:41:47 +1100291 pid_t pid;
Damien Miller62116dc2001-12-24 01:41:47 +1100292 SHA_CTX sha;
Damien Miller7b10ef42002-01-21 23:44:12 +1100293 struct timeval tv_start, tv_current;
Damien Miller62116dc2001-12-24 01:41:47 +1100294
295 debug3("Reading output from \'%s\'", src->cmdstring);
296
297 if (devnull == -1) {
298 devnull = open("/dev/null", O_RDWR);
299 if (devnull == -1)
Damien Millera8e06ce2003-11-21 23:48:55 +1100300 fatal("Couldn't open /dev/null: %s",
Damien Miller7b10ef42002-01-21 23:44:12 +1100301 strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100302 }
303
304 if (pipe(p) == -1)
305 fatal("Couldn't open pipe: %s", strerror(errno));
306
307 (void)gettimeofday(&tv_start, NULL); /* record start time */
308
309 switch (pid = fork()) {
310 case -1: /* Error */
311 close(p[0]);
312 close(p[1]);
313 fatal("Couldn't fork: %s", strerror(errno));
314 /* NOTREACHED */
315 case 0: /* Child */
316 dup2(devnull, STDIN_FILENO);
317 dup2(p[1], STDOUT_FILENO);
318 dup2(p[1], STDERR_FILENO);
319 close(p[0]);
320 close(p[1]);
321 close(devnull);
322
323 execv(src->path, (char**)(src->args));
Damien Miller7b10ef42002-01-21 23:44:12 +1100324
Damien Millera8e06ce2003-11-21 23:48:55 +1100325 debug("(child) Couldn't exec '%s': %s",
Damien Miller7b10ef42002-01-21 23:44:12 +1100326 src->cmdstring, strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100327 _exit(-1);
328 default: /* Parent */
329 break;
330 }
331
332 RAND_add(&pid, sizeof(&pid), 0.0);
333
334 close(p[1]);
335
336 /* Hash output from child */
337 SHA1_Init(&sha);
Damien Miller62116dc2001-12-24 01:41:47 +1100338
Damien Miller7b10ef42002-01-21 23:44:12 +1100339 cmd_eof = error_abort = msec_elapsed = total_bytes_read = 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100340 while (!error_abort && !cmd_eof) {
341 int ret;
342 struct timeval tv;
343 int msec_remaining;
344
345 (void) gettimeofday(&tv_current, 0);
Damien Miller7b10ef42002-01-21 23:44:12 +1100346 msec_elapsed = timeval_diff(&tv_start, &tv_current);
Damien Miller62116dc2001-12-24 01:41:47 +1100347 if (msec_elapsed >= entropy_timeout_current) {
348 error_abort=1;
349 continue;
350 }
351 msec_remaining = entropy_timeout_current - msec_elapsed;
352
353 FD_ZERO(&rdset);
354 FD_SET(p[0], &rdset);
Damien Miller7b10ef42002-01-21 23:44:12 +1100355 tv.tv_sec = msec_remaining / 1000;
Damien Miller62116dc2001-12-24 01:41:47 +1100356 tv.tv_usec = (msec_remaining % 1000) * 1000;
357
Damien Miller7b10ef42002-01-21 23:44:12 +1100358 ret = select(p[0] + 1, &rdset, NULL, NULL, &tv);
Damien Miller62116dc2001-12-24 01:41:47 +1100359
360 RAND_add(&tv, sizeof(tv), 0.0);
361
362 switch (ret) {
363 case 0:
364 /* timer expired */
365 error_abort = 1;
Damien Miller5a5da882002-10-21 10:13:35 +1000366 kill(pid, SIGINT);
Damien Miller62116dc2001-12-24 01:41:47 +1100367 break;
368 case 1:
369 /* command input */
370 do {
371 bytes_read = read(p[0], buf, sizeof(buf));
372 } while (bytes_read == -1 && errno == EINTR);
373 RAND_add(&bytes_read, sizeof(&bytes_read), 0.0);
374 if (bytes_read == -1) {
375 error_abort = 1;
376 break;
377 } else if (bytes_read) {
378 SHA1_Update(&sha, buf, bytes_read);
379 total_bytes_read += bytes_read;
380 } else {
381 cmd_eof = 1;
382 }
383 break;
384 case -1:
385 default:
386 /* error */
Damien Millera8e06ce2003-11-21 23:48:55 +1100387 debug("Command '%s': select() failed: %s",
Damien Miller7b10ef42002-01-21 23:44:12 +1100388 src->cmdstring, strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100389 error_abort = 1;
390 break;
391 }
392 }
393
394 SHA1_Final(hash, &sha);
395
396 close(p[0]);
397
398 debug3("Time elapsed: %d msec", msec_elapsed);
399
400 if (waitpid(pid, &status, 0) == -1) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100401 error("Couldn't wait for child '%s' completion: %s",
Ben Lindstrom5a6abda2002-06-09 19:41:48 +0000402 src->cmdstring, strerror(errno));
Damien Miller7b10ef42002-01-21 23:44:12 +1100403 return 0.0;
Damien Miller62116dc2001-12-24 01:41:47 +1100404 }
405
406 RAND_add(&status, sizeof(&status), 0.0);
407
408 if (error_abort) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100409 /*
410 * Closing p[0] on timeout causes the entropy command to
Damien Millera8e06ce2003-11-21 23:48:55 +1100411 * SIGPIPE. Take whatever output we got, and mark this
412 * command as slow
Damien Miller7b10ef42002-01-21 23:44:12 +1100413 */
Damien Miller62116dc2001-12-24 01:41:47 +1100414 debug2("Command '%s' timed out", src->cmdstring);
415 src->sticky_badness *= 2;
416 src->badness = src->sticky_badness;
Damien Miller7b10ef42002-01-21 23:44:12 +1100417 return total_bytes_read;
Damien Miller62116dc2001-12-24 01:41:47 +1100418 }
419
420 if (WIFEXITED(status)) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100421 if (WEXITSTATUS(status) == 0) {
422 return total_bytes_read;
Damien Miller62116dc2001-12-24 01:41:47 +1100423 } else {
Damien Miller7b10ef42002-01-21 23:44:12 +1100424 debug2("Command '%s' exit status was %d",
425 src->cmdstring, WEXITSTATUS(status));
Damien Miller62116dc2001-12-24 01:41:47 +1100426 src->badness = src->sticky_badness = 128;
Damien Miller7b10ef42002-01-21 23:44:12 +1100427 return 0.0;
Damien Miller62116dc2001-12-24 01:41:47 +1100428 }
429 } else if (WIFSIGNALED(status)) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100430 debug2("Command '%s' returned on uncaught signal %d !",
431 src->cmdstring, status);
Damien Miller62116dc2001-12-24 01:41:47 +1100432 src->badness = src->sticky_badness = 128;
Damien Miller7b10ef42002-01-21 23:44:12 +1100433 return 0.0;
Damien Miller62116dc2001-12-24 01:41:47 +1100434 } else
Damien Miller7b10ef42002-01-21 23:44:12 +1100435 return 0.0;
436}
437
438double
439stir_from_system(void)
440{
441 double total_entropy_estimate;
442 long int i;
443
444 total_entropy_estimate = 0;
445
446 i = getpid();
447 RAND_add(&i, sizeof(i), 0.5);
448 total_entropy_estimate += 0.1;
449
450 i = getppid();
451 RAND_add(&i, sizeof(i), 0.5);
452 total_entropy_estimate += 0.1;
453
454 i = getuid();
455 RAND_add(&i, sizeof(i), 0.0);
456 i = getgid();
457 RAND_add(&i, sizeof(i), 0.0);
458
459 total_entropy_estimate += stir_gettimeofday(1.0);
460 total_entropy_estimate += stir_clock(0.5);
461 total_entropy_estimate += stir_rusage(RUSAGE_SELF, 2.0);
462
463 return total_entropy_estimate;
464}
465
466double
467stir_from_programs(void)
468{
469 int c;
470 double entropy, total_entropy;
Kevin Steves4bdb5472002-07-28 20:42:23 +0000471 unsigned char hash[SHA_DIGEST_LENGTH];
Damien Miller7b10ef42002-01-21 23:44:12 +1100472
473 total_entropy = 0;
474 for(c = 0; entropy_cmds[c].path != NULL; c++) {
475 if (!entropy_cmds[c].badness) {
476 /* Hash output from command */
477 entropy = hash_command_output(&entropy_cmds[c],
478 hash);
479
480 /* Scale back estimate by command's rate */
481 entropy *= entropy_cmds[c].rate;
482
483 /* Upper bound of entropy is SHA_DIGEST_LENGTH */
484 if (entropy > SHA_DIGEST_LENGTH)
485 entropy = SHA_DIGEST_LENGTH;
486
487 /* Stir it in */
488 RAND_add(hash, sizeof(hash), entropy);
489
Damien Millera8e06ce2003-11-21 23:48:55 +1100490 debug3("Got %0.2f bytes of entropy from '%s'",
Damien Miller7b10ef42002-01-21 23:44:12 +1100491 entropy, entropy_cmds[c].cmdstring);
492
493 total_entropy += entropy;
494
495 /* Execution time should be a bit unpredictable */
496 total_entropy += stir_gettimeofday(0.05);
497 total_entropy += stir_clock(0.05);
498 total_entropy += stir_rusage(RUSAGE_SELF, 0.1);
499 total_entropy += stir_rusage(RUSAGE_CHILDREN, 0.1);
500 } else {
501 debug2("Command '%s' disabled (badness %d)",
Damien Millera8e06ce2003-11-21 23:48:55 +1100502 entropy_cmds[c].cmdstring,
Damien Miller7b10ef42002-01-21 23:44:12 +1100503 entropy_cmds[c].badness);
504
505 if (entropy_cmds[c].badness > 0)
506 entropy_cmds[c].badness--;
507 }
508 }
509
510 return total_entropy;
Damien Miller62116dc2001-12-24 01:41:47 +1100511}
512
513/*
514 * prng seedfile functions
515 */
516int
Damien Miller7b10ef42002-01-21 23:44:12 +1100517prng_check_seedfile(char *filename)
518{
Damien Miller62116dc2001-12-24 01:41:47 +1100519 struct stat st;
520
Damien Miller7b10ef42002-01-21 23:44:12 +1100521 /*
Damien Millera8e06ce2003-11-21 23:48:55 +1100522 * XXX raceable: eg replace seed between this stat and subsequent
523 * open. Not such a problem because we don't really trust the
Damien Miller7b10ef42002-01-21 23:44:12 +1100524 * seed file anyway.
525 * XXX: use secure path checking as elsewhere in OpenSSH
526 */
Damien Miller62116dc2001-12-24 01:41:47 +1100527 if (lstat(filename, &st) == -1) {
528 /* Give up on hard errors */
529 if (errno != ENOENT)
Damien Miller7b10ef42002-01-21 23:44:12 +1100530 debug("WARNING: Couldn't stat random seed file "
531 "\"%.100s\": %s", filename, strerror(errno));
532 return 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100533 }
534
535 /* regular file? */
536 if (!S_ISREG(st.st_mode))
Damien Miller7b10ef42002-01-21 23:44:12 +1100537 fatal("PRNG seedfile %.100s is not a regular file",
538 filename);
Damien Miller62116dc2001-12-24 01:41:47 +1100539
540 /* mode 0600, owned by root or the current user? */
541 if (((st.st_mode & 0177) != 0) || !(st.st_uid == getuid())) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100542 debug("WARNING: PRNG seedfile %.100s must be mode 0600, "
Damien Millerc46b6bc2003-05-16 15:51:44 +1000543 "owned by uid %li", filename, (long int)getuid());
Damien Miller7b10ef42002-01-21 23:44:12 +1100544 return 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100545 }
546
Damien Miller7b10ef42002-01-21 23:44:12 +1100547 return 1;
Damien Miller62116dc2001-12-24 01:41:47 +1100548}
549
550void
Damien Miller7b10ef42002-01-21 23:44:12 +1100551prng_write_seedfile(void)
552{
Damien Millered462d92005-02-16 13:02:45 +1100553 int fd, save_errno;
Kevin Steves4bdb5472002-07-28 20:42:23 +0000554 unsigned char seed[SEED_FILE_SIZE];
Damien Millered462d92005-02-16 13:02:45 +1100555 char filename[MAXPATHLEN], tmpseed[MAXPATHLEN];
Damien Miller62116dc2001-12-24 01:41:47 +1100556 struct passwd *pw;
Damien Millered462d92005-02-16 13:02:45 +1100557 mode_t old_umask;
Damien Miller62116dc2001-12-24 01:41:47 +1100558
559 pw = getpwuid(getuid());
560 if (pw == NULL)
Damien Miller7b10ef42002-01-21 23:44:12 +1100561 fatal("Couldn't get password entry for current user "
Damien Millerc46b6bc2003-05-16 15:51:44 +1000562 "(%li): %s", (long int)getuid(), strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100563
564 /* Try to ensure that the parent directory is there */
565 snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir,
Damien Miller7b10ef42002-01-21 23:44:12 +1100566 _PATH_SSH_USER_DIR);
Damien Miller62116dc2001-12-24 01:41:47 +1100567 mkdir(filename, 0700);
568
569 snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir,
Damien Miller7b10ef42002-01-21 23:44:12 +1100570 SSH_PRNG_SEED_FILE);
Damien Miller62116dc2001-12-24 01:41:47 +1100571
Damien Millered462d92005-02-16 13:02:45 +1100572 strlcpy(tmpseed, filename, sizeof(tmpseed));
573 if (strlcat(tmpseed, ".XXXXXXXXXX", sizeof(tmpseed)) >=
574 sizeof(tmpseed))
575 fatal("PRNG seed filename too long");
Damien Miller62116dc2001-12-24 01:41:47 +1100576
Damien Millercafbcc72003-03-17 16:13:53 +1100577 if (RAND_bytes(seed, sizeof(seed)) <= 0)
Ben Lindstromda4d9cf2003-09-22 15:36:15 +0000578 fatal("PRNG seed extraction failed");
Damien Miller62116dc2001-12-24 01:41:47 +1100579
580 /* Don't care if the seed doesn't exist */
581 prng_check_seedfile(filename);
582
Damien Millered462d92005-02-16 13:02:45 +1100583 old_umask = umask(0177);
584
585 if ((fd = mkstemp(tmpseed)) == -1) {
586 debug("WARNING: couldn't make temporary PRNG seedfile %.100s "
587 "(%.100s)", tmpseed, strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100588 } else {
Damien Millered462d92005-02-16 13:02:45 +1100589 debug("writing PRNG seed to file %.100s", tmpseed);
590 if (atomicio(vwrite, fd, &seed, sizeof(seed)) < sizeof(seed)) {
591 save_errno = errno;
592 close(fd);
593 unlink(tmpseed);
Damien Miller7b10ef42002-01-21 23:44:12 +1100594 fatal("problem writing PRNG seedfile %.100s "
Damien Millered462d92005-02-16 13:02:45 +1100595 "(%.100s)", filename, strerror(save_errno));
596 }
Damien Miller62116dc2001-12-24 01:41:47 +1100597 close(fd);
Damien Millered462d92005-02-16 13:02:45 +1100598 debug("moving temporary PRNG seed to file %.100s", filename);
599 if (rename(tmpseed, filename) == -1) {
600 save_errno = errno;
601 unlink(tmpseed);
602 fatal("problem renaming PRNG seedfile from %.100s "
603 "to %.100s (%.100s)", tmpseed, filename,
604 strerror(save_errno));
605 }
Damien Miller62116dc2001-12-24 01:41:47 +1100606 }
Damien Millered462d92005-02-16 13:02:45 +1100607 umask(old_umask);
Damien Miller62116dc2001-12-24 01:41:47 +1100608}
609
610void
Damien Miller7b10ef42002-01-21 23:44:12 +1100611prng_read_seedfile(void)
612{
Damien Miller62116dc2001-12-24 01:41:47 +1100613 int fd;
Damien Miller7b10ef42002-01-21 23:44:12 +1100614 char seed[SEED_FILE_SIZE], filename[MAXPATHLEN];
Damien Miller62116dc2001-12-24 01:41:47 +1100615 struct passwd *pw;
616
617 pw = getpwuid(getuid());
618 if (pw == NULL)
Damien Miller7b10ef42002-01-21 23:44:12 +1100619 fatal("Couldn't get password entry for current user "
Damien Millerc46b6bc2003-05-16 15:51:44 +1000620 "(%li): %s", (long int)getuid(), strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100621
622 snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir,
623 SSH_PRNG_SEED_FILE);
624
625 debug("loading PRNG seed from file %.100s", filename);
626
627 if (!prng_check_seedfile(filename)) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100628 verbose("Random seed file not found or invalid, ignoring.");
Damien Miller62116dc2001-12-24 01:41:47 +1100629 return;
630 }
631
632 /* open the file and read in the seed */
633 fd = open(filename, O_RDONLY);
634 if (fd == -1)
Damien Miller7b10ef42002-01-21 23:44:12 +1100635 fatal("could not open PRNG seedfile %.100s (%.100s)",
636 filename, strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100637
Damien Miller7b10ef42002-01-21 23:44:12 +1100638 if (atomicio(read, fd, &seed, sizeof(seed)) < sizeof(seed)) {
639 verbose("invalid or short read from PRNG seedfile "
640 "%.100s - ignoring", filename);
Damien Miller62116dc2001-12-24 01:41:47 +1100641 memset(seed, '\0', sizeof(seed));
642 }
643 close(fd);
644
645 /* stir in the seed, with estimated entropy zero */
646 RAND_add(&seed, sizeof(seed), 0.0);
647}
648
649
650/*
651 * entropy command initialisation functions
652 */
653int
654prng_read_commands(char *cmdfilename)
655{
Damien Miller7b10ef42002-01-21 23:44:12 +1100656 char cmd[SEED_FILE_SIZE], *cp, line[1024], path[SEED_FILE_SIZE];
Damien Miller62116dc2001-12-24 01:41:47 +1100657 double est;
Damien Miller7b10ef42002-01-21 23:44:12 +1100658 entropy_cmd_t *entcmd;
659 FILE *f;
660 int cur_cmd, linenum, num_cmds, arg;
Damien Miller62116dc2001-12-24 01:41:47 +1100661
Damien Miller7b10ef42002-01-21 23:44:12 +1100662 if ((f = fopen(cmdfilename, "r")) == NULL) {
Damien Miller62116dc2001-12-24 01:41:47 +1100663 fatal("couldn't read entropy commands file %.100s: %.100s",
664 cmdfilename, strerror(errno));
665 }
666
Damien Miller7b10ef42002-01-21 23:44:12 +1100667 num_cmds = 64;
668 entcmd = xmalloc(num_cmds * sizeof(entropy_cmd_t));
669 memset(entcmd, '\0', num_cmds * sizeof(entropy_cmd_t));
Damien Miller62116dc2001-12-24 01:41:47 +1100670
671 /* Read in file */
Damien Miller7b10ef42002-01-21 23:44:12 +1100672 cur_cmd = linenum = 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100673 while (fgets(line, sizeof(line), f)) {
Damien Miller62116dc2001-12-24 01:41:47 +1100674 linenum++;
675
Damien Miller7b10ef42002-01-21 23:44:12 +1100676 /* Skip leading whitespace, blank lines and comments */
Damien Miller62116dc2001-12-24 01:41:47 +1100677 cp = line + strspn(line, WHITESPACE);
678 if ((*cp == 0) || (*cp == '#'))
679 continue; /* done with this line */
680
Damien Miller7b10ef42002-01-21 23:44:12 +1100681 /*
Damien Millera8e06ce2003-11-21 23:48:55 +1100682 * The first non-whitespace char should be a double quote
Damien Miller7b10ef42002-01-21 23:44:12 +1100683 * delimiting the commandline
684 */
Damien Miller62116dc2001-12-24 01:41:47 +1100685 if (*cp != '"') {
Damien Miller7b10ef42002-01-21 23:44:12 +1100686 error("bad entropy command, %.100s line %d",
687 cmdfilename, linenum);
Damien Miller62116dc2001-12-24 01:41:47 +1100688 continue;
689 }
690
Damien Miller7b10ef42002-01-21 23:44:12 +1100691 /*
692 * First token, command args (incl. argv[0]) in double
693 * quotes
694 */
Damien Miller62116dc2001-12-24 01:41:47 +1100695 cp = strtok(cp, "\"");
696 if (cp == NULL) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100697 error("missing or bad command string, %.100s "
698 "line %d -- ignored", cmdfilename, linenum);
Damien Miller62116dc2001-12-24 01:41:47 +1100699 continue;
700 }
701 strlcpy(cmd, cp, sizeof(cmd));
702
Damien Miller7b10ef42002-01-21 23:44:12 +1100703 /* Second token, full command path */
Damien Miller62116dc2001-12-24 01:41:47 +1100704 if ((cp = strtok(NULL, WHITESPACE)) == NULL) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100705 error("missing command path, %.100s "
706 "line %d -- ignored", cmdfilename, linenum);
Damien Miller62116dc2001-12-24 01:41:47 +1100707 continue;
708 }
709
Damien Miller7b10ef42002-01-21 23:44:12 +1100710 /* Did configure mark this as dead? */
Damien Miller62116dc2001-12-24 01:41:47 +1100711 if (strncmp("undef", cp, 5) == 0)
712 continue;
713
714 strlcpy(path, cp, sizeof(path));
715
Damien Miller7b10ef42002-01-21 23:44:12 +1100716 /* Third token, entropy rate estimate for this command */
Damien Miller62116dc2001-12-24 01:41:47 +1100717 if ((cp = strtok(NULL, WHITESPACE)) == NULL) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100718 error("missing entropy estimate, %.100s "
719 "line %d -- ignored", cmdfilename, linenum);
Damien Miller62116dc2001-12-24 01:41:47 +1100720 continue;
721 }
Damien Miller7b10ef42002-01-21 23:44:12 +1100722 est = strtod(cp, NULL);
Damien Miller62116dc2001-12-24 01:41:47 +1100723
724 /* end of line */
725 if ((cp = strtok(NULL, WHITESPACE)) != NULL) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100726 error("garbage at end of line %d in %.100s "
727 "-- ignored", linenum, cmdfilename);
Damien Miller62116dc2001-12-24 01:41:47 +1100728 continue;
729 }
730
731 /* save the command for debug messages */
732 entcmd[cur_cmd].cmdstring = xstrdup(cmd);
733
734 /* split the command args */
735 cp = strtok(cmd, WHITESPACE);
736 arg = 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100737 do {
Damien Miller7b10ef42002-01-21 23:44:12 +1100738 entcmd[cur_cmd].args[arg] = xstrdup(cp);
Damien Miller62116dc2001-12-24 01:41:47 +1100739 arg++;
Damien Miller7b10ef42002-01-21 23:44:12 +1100740 } while(arg < NUM_ARGS && (cp = strtok(NULL, WHITESPACE)));
Damien Miller62116dc2001-12-24 01:41:47 +1100741
742 if (strtok(NULL, WHITESPACE))
Damien Miller7b10ef42002-01-21 23:44:12 +1100743 error("ignored extra commands (max %d), %.100s "
744 "line %d", NUM_ARGS, cmdfilename, linenum);
Damien Miller62116dc2001-12-24 01:41:47 +1100745
746 /* Copy the command path and rate estimate */
747 entcmd[cur_cmd].path = xstrdup(path);
748 entcmd[cur_cmd].rate = est;
749
750 /* Initialise other values */
751 entcmd[cur_cmd].sticky_badness = 1;
752
753 cur_cmd++;
754
Damien Miller7b10ef42002-01-21 23:44:12 +1100755 /*
756 * If we've filled the array, reallocate it twice the size
Damien Millera8e06ce2003-11-21 23:48:55 +1100757 * Do this now because even if this we're on the last
Damien Miller7b10ef42002-01-21 23:44:12 +1100758 * command we need another slot to mark the last entry
759 */
Damien Miller62116dc2001-12-24 01:41:47 +1100760 if (cur_cmd == num_cmds) {
761 num_cmds *= 2;
Damien Miller7b10ef42002-01-21 23:44:12 +1100762 entcmd = xrealloc(entcmd, num_cmds *
763 sizeof(entropy_cmd_t));
Damien Miller62116dc2001-12-24 01:41:47 +1100764 }
765 }
766
767 /* zero the last entry */
Damien Miller7b10ef42002-01-21 23:44:12 +1100768 memset(&entcmd[cur_cmd], '\0', sizeof(entropy_cmd_t));
Damien Miller62116dc2001-12-24 01:41:47 +1100769
770 /* trim to size */
Damien Miller7b10ef42002-01-21 23:44:12 +1100771 entropy_cmds = xrealloc(entcmd, (cur_cmd + 1) *
772 sizeof(entropy_cmd_t));
Damien Miller62116dc2001-12-24 01:41:47 +1100773
Damien Miller7b10ef42002-01-21 23:44:12 +1100774 debug("Loaded %d entropy commands from %.100s", cur_cmd,
775 cmdfilename);
Damien Miller62116dc2001-12-24 01:41:47 +1100776
Damien Miller7b10ef42002-01-21 23:44:12 +1100777 return cur_cmd < MIN_ENTROPY_SOURCES ? -1 : 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100778}
779
Damien Miller32e48182002-04-14 19:27:12 +1000780void
781usage(void)
782{
783 fprintf(stderr, "Usage: %s [options]\n", __progname);
784 fprintf(stderr, " -v Verbose; display verbose debugging messages.\n");
785 fprintf(stderr, " Multiple -v increases verbosity.\n");
Damien Miller7daf0442004-08-23 21:52:08 +1000786 fprintf(stderr, " -x Force output in hexadecimal (for debugging)\n");
Damien Miller32e48182002-04-14 19:27:12 +1000787 fprintf(stderr, " -X Force output in binary\n");
788 fprintf(stderr, " -b bytes Number of bytes to output (default %d)\n",
789 OUTPUT_SEED_SIZE);
790}
791
Damien Millera8e06ce2003-11-21 23:48:55 +1100792int
Damien Miller62116dc2001-12-24 01:41:47 +1100793main(int argc, char **argv)
794{
Damien Miller32e48182002-04-14 19:27:12 +1000795 unsigned char *buf;
796 int ret, ch, debug_level, output_hex, bytes;
797 extern char *optarg;
798 LogLevel ll;
Damien Miller62116dc2001-12-24 01:41:47 +1100799
Damien Miller59d3d5b2003-08-22 09:34:41 +1000800 __progname = ssh_get_progname(argv[0]);
Damien Miller62116dc2001-12-24 01:41:47 +1100801 log_init(argv[0], SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_USER, 1);
802
Damien Miller32e48182002-04-14 19:27:12 +1000803 ll = SYSLOG_LEVEL_INFO;
804 debug_level = output_hex = 0;
805 bytes = OUTPUT_SEED_SIZE;
806
807 /* Don't write binary data to a tty, unless we are forced to */
808 if (isatty(STDOUT_FILENO))
809 output_hex = 1;
Damien Miller787b2ec2003-11-21 23:56:47 +1100810
Damien Miller32e48182002-04-14 19:27:12 +1000811 while ((ch = getopt(argc, argv, "vxXhb:")) != -1) {
812 switch (ch) {
813 case 'v':
814 if (debug_level < 3)
815 ll = SYSLOG_LEVEL_DEBUG1 + debug_level++;
816 break;
817 case 'x':
818 output_hex = 1;
819 break;
820 case 'X':
821 output_hex = 0;
822 break;
823 case 'b':
824 if ((bytes = atoi(optarg)) <= 0)
825 fatal("Invalid number of output bytes");
826 break;
827 case 'h':
828 usage();
829 exit(0);
830 default:
831 error("Invalid commandline option");
832 usage();
833 }
834 }
835
836 log_init(argv[0], ll, SYSLOG_FACILITY_USER, 1);
Damien Miller787b2ec2003-11-21 23:56:47 +1100837
Damien Miller7b10ef42002-01-21 23:44:12 +1100838#ifdef USE_SEED_FILES
839 prng_read_seedfile();
840#endif
841
Damien Miller32e48182002-04-14 19:27:12 +1000842 buf = xmalloc(bytes);
843
Damien Miller7b10ef42002-01-21 23:44:12 +1100844 /*
845 * Seed the RNG from wherever we can
846 */
Damien Miller787b2ec2003-11-21 23:56:47 +1100847
Damien Miller7b10ef42002-01-21 23:44:12 +1100848 /* Take whatever is on the stack, but don't credit it */
Damien Miller32e48182002-04-14 19:27:12 +1000849 RAND_add(buf, bytes, 0);
Damien Miller7b10ef42002-01-21 23:44:12 +1100850
Damien Millera8e06ce2003-11-21 23:48:55 +1100851 debug("Seeded RNG with %i bytes from system calls",
Damien Miller7b10ef42002-01-21 23:44:12 +1100852 (int)stir_from_system());
853
Darren Tucker8686ed72004-12-20 12:05:08 +1100854 /* try prngd, fall back to commands if prngd fails or not configured */
855 if (seed_from_prngd(buf, bytes) == 0) {
856 RAND_add(buf, bytes, bytes);
857 } else {
858 /* Read in collection commands */
859 if (prng_read_commands(SSH_PRNG_COMMAND_FILE) == -1)
860 fatal("PRNG initialisation failed -- exiting.");
861 debug("Seeded RNG with %i bytes from programs",
862 (int)stir_from_programs());
863 }
Damien Miller7b10ef42002-01-21 23:44:12 +1100864
865#ifdef USE_SEED_FILES
866 prng_write_seedfile();
867#endif
868
869 /*
870 * Write the seed to stdout
871 */
Damien Miller62116dc2001-12-24 01:41:47 +1100872
873 if (!RAND_status())
874 fatal("Not enough entropy in RNG");
875
Damien Millercafbcc72003-03-17 16:13:53 +1100876 if (RAND_bytes(buf, bytes) <= 0)
877 fatal("Couldn't extract entropy from PRNG");
Damien Miller62116dc2001-12-24 01:41:47 +1100878
Damien Miller32e48182002-04-14 19:27:12 +1000879 if (output_hex) {
880 for(ret = 0; ret < bytes; ret++)
881 printf("%02x", (unsigned char)(buf[ret]));
882 printf("\n");
883 } else
Darren Tucker8661b562003-07-06 15:20:46 +1000884 ret = atomicio(vwrite, STDOUT_FILENO, buf, bytes);
Damien Miller787b2ec2003-11-21 23:56:47 +1100885
Damien Miller32e48182002-04-14 19:27:12 +1000886 memset(buf, '\0', bytes);
887 xfree(buf);
Damien Miller787b2ec2003-11-21 23:56:47 +1100888
Damien Miller32e48182002-04-14 19:27:12 +1000889 return ret == bytes ? 0 : 1;
Damien Miller62116dc2001-12-24 01:41:47 +1100890}
Darren Tucker7b48d252005-02-16 13:20:07 +1100891
892/*
893 * We may attempt to re-seed during mkstemp if we are using the one in the
Darren Tucker7a8619a2005-02-16 13:32:30 +1100894 * compat library (via mkstemp -> _gettemp -> arc4random -> seed_rng) so we
895 * need our own seed_rng(). We must also check that we have enough entropy.
Darren Tucker7b48d252005-02-16 13:20:07 +1100896 */
897void
898seed_rng(void)
899{
900 if (!RAND_status())
901 fatal("Not enough entropy in RNG");
902}