blob: 8cad53fe667836c02cbb98c63282dc83bfb349b4 [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
Damien Miller7daf0442004-08-23 21:52:08 +100042RCSID("$Id: ssh-rand-helper.c,v 1.19 2004/08/23 11:52:09 djm 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
212double
213stir_gettimeofday(double entropy_estimate)
214{
215 struct timeval tv;
216
217 if (gettimeofday(&tv, NULL) == -1)
218 fatal("Couldn't gettimeofday: %s", strerror(errno));
219
220 RAND_add(&tv, sizeof(tv), entropy_estimate);
221
Damien Miller7b10ef42002-01-21 23:44:12 +1100222 return entropy_estimate;
Damien Miller62116dc2001-12-24 01:41:47 +1100223}
224
225double
226stir_clock(double entropy_estimate)
227{
228#ifdef HAVE_CLOCK
229 clock_t c;
230
231 c = clock();
232 RAND_add(&c, sizeof(c), entropy_estimate);
233
Damien Miller7b10ef42002-01-21 23:44:12 +1100234 return entropy_estimate;
Damien Miller62116dc2001-12-24 01:41:47 +1100235#else /* _HAVE_CLOCK */
Damien Miller7b10ef42002-01-21 23:44:12 +1100236 return 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100237#endif /* _HAVE_CLOCK */
238}
239
240double
241stir_rusage(int who, double entropy_estimate)
242{
243#ifdef HAVE_GETRUSAGE
244 struct rusage ru;
245
246 if (getrusage(who, &ru) == -1)
Damien Miller7b10ef42002-01-21 23:44:12 +1100247 return 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100248
249 RAND_add(&ru, sizeof(ru), entropy_estimate);
250
Damien Miller7b10ef42002-01-21 23:44:12 +1100251 return entropy_estimate;
Damien Miller62116dc2001-12-24 01:41:47 +1100252#else /* _HAVE_GETRUSAGE */
Damien Miller7b10ef42002-01-21 23:44:12 +1100253 return 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100254#endif /* _HAVE_GETRUSAGE */
255}
256
Damien Miller62116dc2001-12-24 01:41:47 +1100257static int
Damien Miller7b10ef42002-01-21 23:44:12 +1100258timeval_diff(struct timeval *t1, struct timeval *t2)
259{
Damien Miller62116dc2001-12-24 01:41:47 +1100260 int secdiff, usecdiff;
261
262 secdiff = t2->tv_sec - t1->tv_sec;
263 usecdiff = (secdiff*1000000) + (t2->tv_usec - t1->tv_usec);
264 return (int)(usecdiff / 1000);
265}
266
267double
Kevin Steves4bdb5472002-07-28 20:42:23 +0000268hash_command_output(entropy_cmd_t *src, unsigned char *hash)
Damien Miller62116dc2001-12-24 01:41:47 +1100269{
Damien Miller7b10ef42002-01-21 23:44:12 +1100270 char buf[8192];
Damien Miller62116dc2001-12-24 01:41:47 +1100271 fd_set rdset;
Damien Miller7b10ef42002-01-21 23:44:12 +1100272 int bytes_read, cmd_eof, error_abort, msec_elapsed, p[2];
273 int status, total_bytes_read;
274 static int devnull = -1;
Damien Miller62116dc2001-12-24 01:41:47 +1100275 pid_t pid;
Damien Miller62116dc2001-12-24 01:41:47 +1100276 SHA_CTX sha;
Damien Miller7b10ef42002-01-21 23:44:12 +1100277 struct timeval tv_start, tv_current;
Damien Miller62116dc2001-12-24 01:41:47 +1100278
279 debug3("Reading output from \'%s\'", src->cmdstring);
280
281 if (devnull == -1) {
282 devnull = open("/dev/null", O_RDWR);
283 if (devnull == -1)
Damien Millera8e06ce2003-11-21 23:48:55 +1100284 fatal("Couldn't open /dev/null: %s",
Damien Miller7b10ef42002-01-21 23:44:12 +1100285 strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100286 }
287
288 if (pipe(p) == -1)
289 fatal("Couldn't open pipe: %s", strerror(errno));
290
291 (void)gettimeofday(&tv_start, NULL); /* record start time */
292
293 switch (pid = fork()) {
294 case -1: /* Error */
295 close(p[0]);
296 close(p[1]);
297 fatal("Couldn't fork: %s", strerror(errno));
298 /* NOTREACHED */
299 case 0: /* Child */
300 dup2(devnull, STDIN_FILENO);
301 dup2(p[1], STDOUT_FILENO);
302 dup2(p[1], STDERR_FILENO);
303 close(p[0]);
304 close(p[1]);
305 close(devnull);
306
307 execv(src->path, (char**)(src->args));
Damien Miller7b10ef42002-01-21 23:44:12 +1100308
Damien Millera8e06ce2003-11-21 23:48:55 +1100309 debug("(child) Couldn't exec '%s': %s",
Damien Miller7b10ef42002-01-21 23:44:12 +1100310 src->cmdstring, strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100311 _exit(-1);
312 default: /* Parent */
313 break;
314 }
315
316 RAND_add(&pid, sizeof(&pid), 0.0);
317
318 close(p[1]);
319
320 /* Hash output from child */
321 SHA1_Init(&sha);
Damien Miller62116dc2001-12-24 01:41:47 +1100322
Damien Miller7b10ef42002-01-21 23:44:12 +1100323 cmd_eof = error_abort = msec_elapsed = total_bytes_read = 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100324 while (!error_abort && !cmd_eof) {
325 int ret;
326 struct timeval tv;
327 int msec_remaining;
328
329 (void) gettimeofday(&tv_current, 0);
Damien Miller7b10ef42002-01-21 23:44:12 +1100330 msec_elapsed = timeval_diff(&tv_start, &tv_current);
Damien Miller62116dc2001-12-24 01:41:47 +1100331 if (msec_elapsed >= entropy_timeout_current) {
332 error_abort=1;
333 continue;
334 }
335 msec_remaining = entropy_timeout_current - msec_elapsed;
336
337 FD_ZERO(&rdset);
338 FD_SET(p[0], &rdset);
Damien Miller7b10ef42002-01-21 23:44:12 +1100339 tv.tv_sec = msec_remaining / 1000;
Damien Miller62116dc2001-12-24 01:41:47 +1100340 tv.tv_usec = (msec_remaining % 1000) * 1000;
341
Damien Miller7b10ef42002-01-21 23:44:12 +1100342 ret = select(p[0] + 1, &rdset, NULL, NULL, &tv);
Damien Miller62116dc2001-12-24 01:41:47 +1100343
344 RAND_add(&tv, sizeof(tv), 0.0);
345
346 switch (ret) {
347 case 0:
348 /* timer expired */
349 error_abort = 1;
Damien Miller5a5da882002-10-21 10:13:35 +1000350 kill(pid, SIGINT);
Damien Miller62116dc2001-12-24 01:41:47 +1100351 break;
352 case 1:
353 /* command input */
354 do {
355 bytes_read = read(p[0], buf, sizeof(buf));
356 } while (bytes_read == -1 && errno == EINTR);
357 RAND_add(&bytes_read, sizeof(&bytes_read), 0.0);
358 if (bytes_read == -1) {
359 error_abort = 1;
360 break;
361 } else if (bytes_read) {
362 SHA1_Update(&sha, buf, bytes_read);
363 total_bytes_read += bytes_read;
364 } else {
365 cmd_eof = 1;
366 }
367 break;
368 case -1:
369 default:
370 /* error */
Damien Millera8e06ce2003-11-21 23:48:55 +1100371 debug("Command '%s': select() failed: %s",
Damien Miller7b10ef42002-01-21 23:44:12 +1100372 src->cmdstring, strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100373 error_abort = 1;
374 break;
375 }
376 }
377
378 SHA1_Final(hash, &sha);
379
380 close(p[0]);
381
382 debug3("Time elapsed: %d msec", msec_elapsed);
383
384 if (waitpid(pid, &status, 0) == -1) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100385 error("Couldn't wait for child '%s' completion: %s",
Ben Lindstrom5a6abda2002-06-09 19:41:48 +0000386 src->cmdstring, strerror(errno));
Damien Miller7b10ef42002-01-21 23:44:12 +1100387 return 0.0;
Damien Miller62116dc2001-12-24 01:41:47 +1100388 }
389
390 RAND_add(&status, sizeof(&status), 0.0);
391
392 if (error_abort) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100393 /*
394 * Closing p[0] on timeout causes the entropy command to
Damien Millera8e06ce2003-11-21 23:48:55 +1100395 * SIGPIPE. Take whatever output we got, and mark this
396 * command as slow
Damien Miller7b10ef42002-01-21 23:44:12 +1100397 */
Damien Miller62116dc2001-12-24 01:41:47 +1100398 debug2("Command '%s' timed out", src->cmdstring);
399 src->sticky_badness *= 2;
400 src->badness = src->sticky_badness;
Damien Miller7b10ef42002-01-21 23:44:12 +1100401 return total_bytes_read;
Damien Miller62116dc2001-12-24 01:41:47 +1100402 }
403
404 if (WIFEXITED(status)) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100405 if (WEXITSTATUS(status) == 0) {
406 return total_bytes_read;
Damien Miller62116dc2001-12-24 01:41:47 +1100407 } else {
Damien Miller7b10ef42002-01-21 23:44:12 +1100408 debug2("Command '%s' exit status was %d",
409 src->cmdstring, WEXITSTATUS(status));
Damien Miller62116dc2001-12-24 01:41:47 +1100410 src->badness = src->sticky_badness = 128;
Damien Miller7b10ef42002-01-21 23:44:12 +1100411 return 0.0;
Damien Miller62116dc2001-12-24 01:41:47 +1100412 }
413 } else if (WIFSIGNALED(status)) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100414 debug2("Command '%s' returned on uncaught signal %d !",
415 src->cmdstring, status);
Damien Miller62116dc2001-12-24 01:41:47 +1100416 src->badness = src->sticky_badness = 128;
Damien Miller7b10ef42002-01-21 23:44:12 +1100417 return 0.0;
Damien Miller62116dc2001-12-24 01:41:47 +1100418 } else
Damien Miller7b10ef42002-01-21 23:44:12 +1100419 return 0.0;
420}
421
422double
423stir_from_system(void)
424{
425 double total_entropy_estimate;
426 long int i;
427
428 total_entropy_estimate = 0;
429
430 i = getpid();
431 RAND_add(&i, sizeof(i), 0.5);
432 total_entropy_estimate += 0.1;
433
434 i = getppid();
435 RAND_add(&i, sizeof(i), 0.5);
436 total_entropy_estimate += 0.1;
437
438 i = getuid();
439 RAND_add(&i, sizeof(i), 0.0);
440 i = getgid();
441 RAND_add(&i, sizeof(i), 0.0);
442
443 total_entropy_estimate += stir_gettimeofday(1.0);
444 total_entropy_estimate += stir_clock(0.5);
445 total_entropy_estimate += stir_rusage(RUSAGE_SELF, 2.0);
446
447 return total_entropy_estimate;
448}
449
450double
451stir_from_programs(void)
452{
453 int c;
454 double entropy, total_entropy;
Kevin Steves4bdb5472002-07-28 20:42:23 +0000455 unsigned char hash[SHA_DIGEST_LENGTH];
Damien Miller7b10ef42002-01-21 23:44:12 +1100456
457 total_entropy = 0;
458 for(c = 0; entropy_cmds[c].path != NULL; c++) {
459 if (!entropy_cmds[c].badness) {
460 /* Hash output from command */
461 entropy = hash_command_output(&entropy_cmds[c],
462 hash);
463
464 /* Scale back estimate by command's rate */
465 entropy *= entropy_cmds[c].rate;
466
467 /* Upper bound of entropy is SHA_DIGEST_LENGTH */
468 if (entropy > SHA_DIGEST_LENGTH)
469 entropy = SHA_DIGEST_LENGTH;
470
471 /* Stir it in */
472 RAND_add(hash, sizeof(hash), entropy);
473
Damien Millera8e06ce2003-11-21 23:48:55 +1100474 debug3("Got %0.2f bytes of entropy from '%s'",
Damien Miller7b10ef42002-01-21 23:44:12 +1100475 entropy, entropy_cmds[c].cmdstring);
476
477 total_entropy += entropy;
478
479 /* Execution time should be a bit unpredictable */
480 total_entropy += stir_gettimeofday(0.05);
481 total_entropy += stir_clock(0.05);
482 total_entropy += stir_rusage(RUSAGE_SELF, 0.1);
483 total_entropy += stir_rusage(RUSAGE_CHILDREN, 0.1);
484 } else {
485 debug2("Command '%s' disabled (badness %d)",
Damien Millera8e06ce2003-11-21 23:48:55 +1100486 entropy_cmds[c].cmdstring,
Damien Miller7b10ef42002-01-21 23:44:12 +1100487 entropy_cmds[c].badness);
488
489 if (entropy_cmds[c].badness > 0)
490 entropy_cmds[c].badness--;
491 }
492 }
493
494 return total_entropy;
Damien Miller62116dc2001-12-24 01:41:47 +1100495}
496
497/*
498 * prng seedfile functions
499 */
500int
Damien Miller7b10ef42002-01-21 23:44:12 +1100501prng_check_seedfile(char *filename)
502{
Damien Miller62116dc2001-12-24 01:41:47 +1100503 struct stat st;
504
Damien Miller7b10ef42002-01-21 23:44:12 +1100505 /*
Damien Millera8e06ce2003-11-21 23:48:55 +1100506 * XXX raceable: eg replace seed between this stat and subsequent
507 * open. Not such a problem because we don't really trust the
Damien Miller7b10ef42002-01-21 23:44:12 +1100508 * seed file anyway.
509 * XXX: use secure path checking as elsewhere in OpenSSH
510 */
Damien Miller62116dc2001-12-24 01:41:47 +1100511 if (lstat(filename, &st) == -1) {
512 /* Give up on hard errors */
513 if (errno != ENOENT)
Damien Miller7b10ef42002-01-21 23:44:12 +1100514 debug("WARNING: Couldn't stat random seed file "
515 "\"%.100s\": %s", filename, strerror(errno));
516 return 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100517 }
518
519 /* regular file? */
520 if (!S_ISREG(st.st_mode))
Damien Miller7b10ef42002-01-21 23:44:12 +1100521 fatal("PRNG seedfile %.100s is not a regular file",
522 filename);
Damien Miller62116dc2001-12-24 01:41:47 +1100523
524 /* mode 0600, owned by root or the current user? */
525 if (((st.st_mode & 0177) != 0) || !(st.st_uid == getuid())) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100526 debug("WARNING: PRNG seedfile %.100s must be mode 0600, "
Damien Millerc46b6bc2003-05-16 15:51:44 +1000527 "owned by uid %li", filename, (long int)getuid());
Damien Miller7b10ef42002-01-21 23:44:12 +1100528 return 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100529 }
530
Damien Miller7b10ef42002-01-21 23:44:12 +1100531 return 1;
Damien Miller62116dc2001-12-24 01:41:47 +1100532}
533
534void
Damien Miller7b10ef42002-01-21 23:44:12 +1100535prng_write_seedfile(void)
536{
Damien Miller62116dc2001-12-24 01:41:47 +1100537 int fd;
Kevin Steves4bdb5472002-07-28 20:42:23 +0000538 unsigned char seed[SEED_FILE_SIZE];
539 char filename[MAXPATHLEN];
Damien Miller62116dc2001-12-24 01:41:47 +1100540 struct passwd *pw;
541
542 pw = getpwuid(getuid());
543 if (pw == NULL)
Damien Miller7b10ef42002-01-21 23:44:12 +1100544 fatal("Couldn't get password entry for current user "
Damien Millerc46b6bc2003-05-16 15:51:44 +1000545 "(%li): %s", (long int)getuid(), strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100546
547 /* Try to ensure that the parent directory is there */
548 snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir,
Damien Miller7b10ef42002-01-21 23:44:12 +1100549 _PATH_SSH_USER_DIR);
Damien Miller62116dc2001-12-24 01:41:47 +1100550 mkdir(filename, 0700);
551
552 snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir,
Damien Miller7b10ef42002-01-21 23:44:12 +1100553 SSH_PRNG_SEED_FILE);
Damien Miller62116dc2001-12-24 01:41:47 +1100554
555 debug("writing PRNG seed to file %.100s", filename);
556
Damien Millercafbcc72003-03-17 16:13:53 +1100557 if (RAND_bytes(seed, sizeof(seed)) <= 0)
Ben Lindstromda4d9cf2003-09-22 15:36:15 +0000558 fatal("PRNG seed extraction failed");
Damien Miller62116dc2001-12-24 01:41:47 +1100559
560 /* Don't care if the seed doesn't exist */
561 prng_check_seedfile(filename);
562
563 if ((fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0600)) == -1) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100564 debug("WARNING: couldn't access PRNG seedfile %.100s "
565 "(%.100s)", filename, strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100566 } else {
Darren Tucker8661b562003-07-06 15:20:46 +1000567 if (atomicio(vwrite, fd, &seed, sizeof(seed)) < sizeof(seed))
Damien Miller7b10ef42002-01-21 23:44:12 +1100568 fatal("problem writing PRNG seedfile %.100s "
569 "(%.100s)", filename, strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100570 close(fd);
571 }
572}
573
574void
Damien Miller7b10ef42002-01-21 23:44:12 +1100575prng_read_seedfile(void)
576{
Damien Miller62116dc2001-12-24 01:41:47 +1100577 int fd;
Damien Miller7b10ef42002-01-21 23:44:12 +1100578 char seed[SEED_FILE_SIZE], filename[MAXPATHLEN];
Damien Miller62116dc2001-12-24 01:41:47 +1100579 struct passwd *pw;
580
581 pw = getpwuid(getuid());
582 if (pw == NULL)
Damien Miller7b10ef42002-01-21 23:44:12 +1100583 fatal("Couldn't get password entry for current user "
Damien Millerc46b6bc2003-05-16 15:51:44 +1000584 "(%li): %s", (long int)getuid(), strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100585
586 snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir,
587 SSH_PRNG_SEED_FILE);
588
589 debug("loading PRNG seed from file %.100s", filename);
590
591 if (!prng_check_seedfile(filename)) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100592 verbose("Random seed file not found or invalid, ignoring.");
Damien Miller62116dc2001-12-24 01:41:47 +1100593 return;
594 }
595
596 /* open the file and read in the seed */
597 fd = open(filename, O_RDONLY);
598 if (fd == -1)
Damien Miller7b10ef42002-01-21 23:44:12 +1100599 fatal("could not open PRNG seedfile %.100s (%.100s)",
600 filename, strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100601
Damien Miller7b10ef42002-01-21 23:44:12 +1100602 if (atomicio(read, fd, &seed, sizeof(seed)) < sizeof(seed)) {
603 verbose("invalid or short read from PRNG seedfile "
604 "%.100s - ignoring", filename);
Damien Miller62116dc2001-12-24 01:41:47 +1100605 memset(seed, '\0', sizeof(seed));
606 }
607 close(fd);
608
609 /* stir in the seed, with estimated entropy zero */
610 RAND_add(&seed, sizeof(seed), 0.0);
611}
612
613
614/*
615 * entropy command initialisation functions
616 */
617int
618prng_read_commands(char *cmdfilename)
619{
Damien Miller7b10ef42002-01-21 23:44:12 +1100620 char cmd[SEED_FILE_SIZE], *cp, line[1024], path[SEED_FILE_SIZE];
Damien Miller62116dc2001-12-24 01:41:47 +1100621 double est;
Damien Miller7b10ef42002-01-21 23:44:12 +1100622 entropy_cmd_t *entcmd;
623 FILE *f;
624 int cur_cmd, linenum, num_cmds, arg;
Damien Miller62116dc2001-12-24 01:41:47 +1100625
Damien Miller7b10ef42002-01-21 23:44:12 +1100626 if ((f = fopen(cmdfilename, "r")) == NULL) {
Damien Miller62116dc2001-12-24 01:41:47 +1100627 fatal("couldn't read entropy commands file %.100s: %.100s",
628 cmdfilename, strerror(errno));
629 }
630
Damien Miller7b10ef42002-01-21 23:44:12 +1100631 num_cmds = 64;
632 entcmd = xmalloc(num_cmds * sizeof(entropy_cmd_t));
633 memset(entcmd, '\0', num_cmds * sizeof(entropy_cmd_t));
Damien Miller62116dc2001-12-24 01:41:47 +1100634
635 /* Read in file */
Damien Miller7b10ef42002-01-21 23:44:12 +1100636 cur_cmd = linenum = 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100637 while (fgets(line, sizeof(line), f)) {
Damien Miller62116dc2001-12-24 01:41:47 +1100638 linenum++;
639
Damien Miller7b10ef42002-01-21 23:44:12 +1100640 /* Skip leading whitespace, blank lines and comments */
Damien Miller62116dc2001-12-24 01:41:47 +1100641 cp = line + strspn(line, WHITESPACE);
642 if ((*cp == 0) || (*cp == '#'))
643 continue; /* done with this line */
644
Damien Miller7b10ef42002-01-21 23:44:12 +1100645 /*
Damien Millera8e06ce2003-11-21 23:48:55 +1100646 * The first non-whitespace char should be a double quote
Damien Miller7b10ef42002-01-21 23:44:12 +1100647 * delimiting the commandline
648 */
Damien Miller62116dc2001-12-24 01:41:47 +1100649 if (*cp != '"') {
Damien Miller7b10ef42002-01-21 23:44:12 +1100650 error("bad entropy command, %.100s line %d",
651 cmdfilename, linenum);
Damien Miller62116dc2001-12-24 01:41:47 +1100652 continue;
653 }
654
Damien Miller7b10ef42002-01-21 23:44:12 +1100655 /*
656 * First token, command args (incl. argv[0]) in double
657 * quotes
658 */
Damien Miller62116dc2001-12-24 01:41:47 +1100659 cp = strtok(cp, "\"");
660 if (cp == NULL) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100661 error("missing or bad command string, %.100s "
662 "line %d -- ignored", cmdfilename, linenum);
Damien Miller62116dc2001-12-24 01:41:47 +1100663 continue;
664 }
665 strlcpy(cmd, cp, sizeof(cmd));
666
Damien Miller7b10ef42002-01-21 23:44:12 +1100667 /* Second token, full command path */
Damien Miller62116dc2001-12-24 01:41:47 +1100668 if ((cp = strtok(NULL, WHITESPACE)) == NULL) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100669 error("missing command path, %.100s "
670 "line %d -- ignored", cmdfilename, linenum);
Damien Miller62116dc2001-12-24 01:41:47 +1100671 continue;
672 }
673
Damien Miller7b10ef42002-01-21 23:44:12 +1100674 /* Did configure mark this as dead? */
Damien Miller62116dc2001-12-24 01:41:47 +1100675 if (strncmp("undef", cp, 5) == 0)
676 continue;
677
678 strlcpy(path, cp, sizeof(path));
679
Damien Miller7b10ef42002-01-21 23:44:12 +1100680 /* Third token, entropy rate estimate for this command */
Damien Miller62116dc2001-12-24 01:41:47 +1100681 if ((cp = strtok(NULL, WHITESPACE)) == NULL) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100682 error("missing entropy estimate, %.100s "
683 "line %d -- ignored", cmdfilename, linenum);
Damien Miller62116dc2001-12-24 01:41:47 +1100684 continue;
685 }
Damien Miller7b10ef42002-01-21 23:44:12 +1100686 est = strtod(cp, NULL);
Damien Miller62116dc2001-12-24 01:41:47 +1100687
688 /* end of line */
689 if ((cp = strtok(NULL, WHITESPACE)) != NULL) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100690 error("garbage at end of line %d in %.100s "
691 "-- ignored", linenum, cmdfilename);
Damien Miller62116dc2001-12-24 01:41:47 +1100692 continue;
693 }
694
695 /* save the command for debug messages */
696 entcmd[cur_cmd].cmdstring = xstrdup(cmd);
697
698 /* split the command args */
699 cp = strtok(cmd, WHITESPACE);
700 arg = 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100701 do {
Damien Miller7b10ef42002-01-21 23:44:12 +1100702 entcmd[cur_cmd].args[arg] = xstrdup(cp);
Damien Miller62116dc2001-12-24 01:41:47 +1100703 arg++;
Damien Miller7b10ef42002-01-21 23:44:12 +1100704 } while(arg < NUM_ARGS && (cp = strtok(NULL, WHITESPACE)));
Damien Miller62116dc2001-12-24 01:41:47 +1100705
706 if (strtok(NULL, WHITESPACE))
Damien Miller7b10ef42002-01-21 23:44:12 +1100707 error("ignored extra commands (max %d), %.100s "
708 "line %d", NUM_ARGS, cmdfilename, linenum);
Damien Miller62116dc2001-12-24 01:41:47 +1100709
710 /* Copy the command path and rate estimate */
711 entcmd[cur_cmd].path = xstrdup(path);
712 entcmd[cur_cmd].rate = est;
713
714 /* Initialise other values */
715 entcmd[cur_cmd].sticky_badness = 1;
716
717 cur_cmd++;
718
Damien Miller7b10ef42002-01-21 23:44:12 +1100719 /*
720 * If we've filled the array, reallocate it twice the size
Damien Millera8e06ce2003-11-21 23:48:55 +1100721 * Do this now because even if this we're on the last
Damien Miller7b10ef42002-01-21 23:44:12 +1100722 * command we need another slot to mark the last entry
723 */
Damien Miller62116dc2001-12-24 01:41:47 +1100724 if (cur_cmd == num_cmds) {
725 num_cmds *= 2;
Damien Miller7b10ef42002-01-21 23:44:12 +1100726 entcmd = xrealloc(entcmd, num_cmds *
727 sizeof(entropy_cmd_t));
Damien Miller62116dc2001-12-24 01:41:47 +1100728 }
729 }
730
731 /* zero the last entry */
Damien Miller7b10ef42002-01-21 23:44:12 +1100732 memset(&entcmd[cur_cmd], '\0', sizeof(entropy_cmd_t));
Damien Miller62116dc2001-12-24 01:41:47 +1100733
734 /* trim to size */
Damien Miller7b10ef42002-01-21 23:44:12 +1100735 entropy_cmds = xrealloc(entcmd, (cur_cmd + 1) *
736 sizeof(entropy_cmd_t));
Damien Miller62116dc2001-12-24 01:41:47 +1100737
Damien Miller7b10ef42002-01-21 23:44:12 +1100738 debug("Loaded %d entropy commands from %.100s", cur_cmd,
739 cmdfilename);
Damien Miller62116dc2001-12-24 01:41:47 +1100740
Damien Miller7b10ef42002-01-21 23:44:12 +1100741 return cur_cmd < MIN_ENTROPY_SOURCES ? -1 : 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100742}
743
Damien Miller32e48182002-04-14 19:27:12 +1000744void
745usage(void)
746{
747 fprintf(stderr, "Usage: %s [options]\n", __progname);
748 fprintf(stderr, " -v Verbose; display verbose debugging messages.\n");
749 fprintf(stderr, " Multiple -v increases verbosity.\n");
Damien Miller7daf0442004-08-23 21:52:08 +1000750 fprintf(stderr, " -x Force output in hexadecimal (for debugging)\n");
Damien Miller32e48182002-04-14 19:27:12 +1000751 fprintf(stderr, " -X Force output in binary\n");
752 fprintf(stderr, " -b bytes Number of bytes to output (default %d)\n",
753 OUTPUT_SEED_SIZE);
754}
755
Damien Millera8e06ce2003-11-21 23:48:55 +1100756int
Damien Miller62116dc2001-12-24 01:41:47 +1100757main(int argc, char **argv)
758{
Damien Miller32e48182002-04-14 19:27:12 +1000759 unsigned char *buf;
760 int ret, ch, debug_level, output_hex, bytes;
761 extern char *optarg;
762 LogLevel ll;
Damien Miller62116dc2001-12-24 01:41:47 +1100763
Damien Miller59d3d5b2003-08-22 09:34:41 +1000764 __progname = ssh_get_progname(argv[0]);
Damien Miller62116dc2001-12-24 01:41:47 +1100765 log_init(argv[0], SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_USER, 1);
766
Damien Miller32e48182002-04-14 19:27:12 +1000767 ll = SYSLOG_LEVEL_INFO;
768 debug_level = output_hex = 0;
769 bytes = OUTPUT_SEED_SIZE;
770
771 /* Don't write binary data to a tty, unless we are forced to */
772 if (isatty(STDOUT_FILENO))
773 output_hex = 1;
Damien Miller787b2ec2003-11-21 23:56:47 +1100774
Damien Miller32e48182002-04-14 19:27:12 +1000775 while ((ch = getopt(argc, argv, "vxXhb:")) != -1) {
776 switch (ch) {
777 case 'v':
778 if (debug_level < 3)
779 ll = SYSLOG_LEVEL_DEBUG1 + debug_level++;
780 break;
781 case 'x':
782 output_hex = 1;
783 break;
784 case 'X':
785 output_hex = 0;
786 break;
787 case 'b':
788 if ((bytes = atoi(optarg)) <= 0)
789 fatal("Invalid number of output bytes");
790 break;
791 case 'h':
792 usage();
793 exit(0);
794 default:
795 error("Invalid commandline option");
796 usage();
797 }
798 }
799
800 log_init(argv[0], ll, SYSLOG_FACILITY_USER, 1);
Damien Miller787b2ec2003-11-21 23:56:47 +1100801
Damien Miller7b10ef42002-01-21 23:44:12 +1100802#ifdef USE_SEED_FILES
803 prng_read_seedfile();
804#endif
805
Damien Miller32e48182002-04-14 19:27:12 +1000806 buf = xmalloc(bytes);
807
Damien Miller7b10ef42002-01-21 23:44:12 +1100808 /*
809 * Seed the RNG from wherever we can
810 */
Damien Miller787b2ec2003-11-21 23:56:47 +1100811
Damien Miller7b10ef42002-01-21 23:44:12 +1100812 /* Take whatever is on the stack, but don't credit it */
Damien Miller32e48182002-04-14 19:27:12 +1000813 RAND_add(buf, bytes, 0);
Damien Miller7b10ef42002-01-21 23:44:12 +1100814
Damien Millera8e06ce2003-11-21 23:48:55 +1100815 debug("Seeded RNG with %i bytes from system calls",
Damien Miller7b10ef42002-01-21 23:44:12 +1100816 (int)stir_from_system());
817
818#ifdef PRNGD_PORT
Damien Miller32e48182002-04-14 19:27:12 +1000819 if (get_random_bytes_prngd(buf, bytes, PRNGD_PORT, NULL) == -1)
Damien Miller7b10ef42002-01-21 23:44:12 +1100820 fatal("Entropy collection failed");
Damien Miller32e48182002-04-14 19:27:12 +1000821 RAND_add(buf, bytes, bytes);
Damien Millerc46cc542002-01-22 21:58:27 +1100822#elif defined(PRNGD_SOCKET)
Damien Miller32e48182002-04-14 19:27:12 +1000823 if (get_random_bytes_prngd(buf, bytes, 0, PRNGD_SOCKET) == -1)
Damien Miller7b10ef42002-01-21 23:44:12 +1100824 fatal("Entropy collection failed");
Damien Miller32e48182002-04-14 19:27:12 +1000825 RAND_add(buf, bytes, bytes);
Damien Miller7b10ef42002-01-21 23:44:12 +1100826#else
827 /* Read in collection commands */
828 if (prng_read_commands(SSH_PRNG_COMMAND_FILE) == -1)
829 fatal("PRNG initialisation failed -- exiting.");
Damien Millera8e06ce2003-11-21 23:48:55 +1100830 debug("Seeded RNG with %i bytes from programs",
Damien Miller7b10ef42002-01-21 23:44:12 +1100831 (int)stir_from_programs());
832#endif
833
834#ifdef USE_SEED_FILES
835 prng_write_seedfile();
836#endif
837
838 /*
839 * Write the seed to stdout
840 */
Damien Miller62116dc2001-12-24 01:41:47 +1100841
842 if (!RAND_status())
843 fatal("Not enough entropy in RNG");
844
Damien Millercafbcc72003-03-17 16:13:53 +1100845 if (RAND_bytes(buf, bytes) <= 0)
846 fatal("Couldn't extract entropy from PRNG");
Damien Miller62116dc2001-12-24 01:41:47 +1100847
Damien Miller32e48182002-04-14 19:27:12 +1000848 if (output_hex) {
849 for(ret = 0; ret < bytes; ret++)
850 printf("%02x", (unsigned char)(buf[ret]));
851 printf("\n");
852 } else
Darren Tucker8661b562003-07-06 15:20:46 +1000853 ret = atomicio(vwrite, STDOUT_FILENO, buf, bytes);
Damien Miller787b2ec2003-11-21 23:56:47 +1100854
Damien Miller32e48182002-04-14 19:27:12 +1000855 memset(buf, '\0', bytes);
856 xfree(buf);
Damien Miller787b2ec2003-11-21 23:56:47 +1100857
Damien Miller32e48182002-04-14 19:27:12 +1000858 return ret == bytes ? 0 : 1;
Damien Miller62116dc2001-12-24 01:41:47 +1100859}