blob: 8a320a71ea76c46f2fdf49db032fb8766fcd4a8d [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 Miller787b2ec2003-11-21 23:56:47 +110042RCSID("$Id: ssh-rand-helper.c,v 1.16 2003/11/21 12:56:47 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 +000066#ifdef HAVE___PROGNAME
67extern char *__progname;
68#else
69char *__progname;
70#endif
71
Damien Miller62116dc2001-12-24 01:41:47 +110072#ifndef offsetof
73# define offsetof(type, member) ((size_t) &((type *)0)->member)
74#endif
75
Damien Miller62116dc2001-12-24 01:41:47 +110076#define WHITESPACE " \t\n"
77
78#ifndef RUSAGE_SELF
79# define RUSAGE_SELF 0
80#endif
81#ifndef RUSAGE_CHILDREN
82# define RUSAGE_CHILDREN 0
83#endif
84
Damien Millerc46cc542002-01-22 21:58:27 +110085#if !defined(PRNGD_SOCKET) && !defined(PRNGD_PORT)
Damien Miller7b10ef42002-01-21 23:44:12 +110086# define USE_SEED_FILES
Damien Miller62116dc2001-12-24 01:41:47 +110087#endif
88
Damien Miller7b10ef42002-01-21 23:44:12 +110089typedef struct {
90 /* Proportion of data that is entropy */
91 double rate;
92 /* Counter goes positive if this command times out */
93 unsigned int badness;
94 /* Increases by factor of two each timeout */
95 unsigned int sticky_badness;
96 /* Path to executable */
97 char *path;
98 /* argv to pass to executable */
99 char *args[NUM_ARGS]; /* XXX: arbitrary limit */
100 /* full command string (debug) */
101 char *cmdstring;
102} entropy_cmd_t;
103
104/* slow command timeouts (all in milliseconds) */
105/* static int entropy_timeout_default = ENTROPY_TIMEOUT_MSEC; */
106static int entropy_timeout_current = ENTROPY_TIMEOUT_MSEC;
107
108/* this is initialised from a file, by prng_read_commands() */
109static entropy_cmd_t *entropy_cmds = NULL;
110
111/* Prototypes */
112double stir_from_system(void);
113double stir_from_programs(void);
114double stir_gettimeofday(double entropy_estimate);
115double stir_clock(double entropy_estimate);
116double stir_rusage(int who, double entropy_estimate);
Kevin Steves4bdb5472002-07-28 20:42:23 +0000117double hash_command_output(entropy_cmd_t *src, unsigned char *hash);
Damien Millera8e06ce2003-11-21 23:48:55 +1100118int get_random_bytes_prngd(unsigned char *buf, int len,
Damien Miller7b10ef42002-01-21 23:44:12 +1100119 unsigned short tcp_port, char *socket_path);
120
121/*
122 * Collect 'len' bytes of entropy into 'buf' from PRNGD/EGD daemon
123 * listening either on 'tcp_port', or via Unix domain socket at *
124 * 'socket_path'.
Damien Millera8e06ce2003-11-21 23:48:55 +1100125 * Either a non-zero tcp_port or a non-null socket_path must be
Damien Miller7b10ef42002-01-21 23:44:12 +1100126 * supplied.
127 * Returns 0 on success, -1 on error
128 */
Damien Miller62116dc2001-12-24 01:41:47 +1100129int
Damien Millera8e06ce2003-11-21 23:48:55 +1100130get_random_bytes_prngd(unsigned char *buf, int len,
Damien Miller7b10ef42002-01-21 23:44:12 +1100131 unsigned short tcp_port, char *socket_path)
Damien Miller62116dc2001-12-24 01:41:47 +1100132{
Damien Miller7b10ef42002-01-21 23:44:12 +1100133 int fd, addr_len, rval, errors;
Damien Miller62116dc2001-12-24 01:41:47 +1100134 char msg[2];
Damien Miller7b10ef42002-01-21 23:44:12 +1100135 struct sockaddr_storage addr;
136 struct sockaddr_in *addr_in = (struct sockaddr_in *)&addr;
137 struct sockaddr_un *addr_un = (struct sockaddr_un *)&addr;
Damien Miller62116dc2001-12-24 01:41:47 +1100138 mysig_t old_sigpipe;
139
Damien Miller7b10ef42002-01-21 23:44:12 +1100140 /* Sanity checks */
141 if (socket_path == NULL && tcp_port == 0)
142 fatal("You must specify a port or a socket");
143 if (socket_path != NULL &&
144 strlen(socket_path) >= sizeof(addr_un->sun_path))
145 fatal("Random pool path is too long");
Damien Miller62116dc2001-12-24 01:41:47 +1100146 if (len > 255)
147 fatal("Too many bytes to read from PRNGD");
148
149 memset(&addr, '\0', sizeof(addr));
150
Damien Miller7b10ef42002-01-21 23:44:12 +1100151 if (tcp_port != 0) {
152 addr_in->sin_family = AF_INET;
153 addr_in->sin_addr.s_addr = htonl(INADDR_LOOPBACK);
154 addr_in->sin_port = htons(tcp_port);
155 addr_len = sizeof(*addr_in);
156 } else {
157 addr_un->sun_family = AF_UNIX;
158 strlcpy(addr_un->sun_path, socket_path,
159 sizeof(addr_un->sun_path));
160 addr_len = offsetof(struct sockaddr_un, sun_path) +
161 strlen(socket_path) + 1;
162 }
Damien Miller62116dc2001-12-24 01:41:47 +1100163
164 old_sigpipe = mysignal(SIGPIPE, SIG_IGN);
165
Damien Miller7b10ef42002-01-21 23:44:12 +1100166 errors = 0;
167 rval = -1;
Damien Miller62116dc2001-12-24 01:41:47 +1100168reopen:
Damien Miller7b10ef42002-01-21 23:44:12 +1100169 fd = socket(addr.ss_family, SOCK_STREAM, 0);
Damien Miller62116dc2001-12-24 01:41:47 +1100170 if (fd == -1) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100171 error("Couldn't create socket: %s", strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100172 goto done;
173 }
Damien Miller62116dc2001-12-24 01:41:47 +1100174
175 if (connect(fd, (struct sockaddr*)&addr, addr_len) == -1) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100176 if (tcp_port != 0) {
177 error("Couldn't connect to PRNGD port %d: %s",
178 tcp_port, strerror(errno));
179 } else {
180 error("Couldn't connect to PRNGD socket \"%s\": %s",
181 addr_un->sun_path, strerror(errno));
182 }
Damien Miller62116dc2001-12-24 01:41:47 +1100183 goto done;
184 }
185
186 /* Send blocking read request to PRNGD */
187 msg[0] = 0x02;
188 msg[1] = len;
189
Darren Tucker8661b562003-07-06 15:20:46 +1000190 if (atomicio(vwrite, fd, msg, sizeof(msg)) != sizeof(msg)) {
Damien Miller62116dc2001-12-24 01:41:47 +1100191 if (errno == EPIPE && errors < 10) {
192 close(fd);
193 errors++;
194 goto reopen;
195 }
196 error("Couldn't write to PRNGD socket: %s",
197 strerror(errno));
198 goto done;
199 }
200
201 if (atomicio(read, fd, buf, len) != len) {
202 if (errno == EPIPE && errors < 10) {
203 close(fd);
204 errors++;
205 goto reopen;
206 }
207 error("Couldn't read from PRNGD socket: %s",
208 strerror(errno));
209 goto done;
210 }
211
Damien Miller7b10ef42002-01-21 23:44:12 +1100212 rval = 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100213done:
214 mysignal(SIGPIPE, old_sigpipe);
215 if (fd != -1)
216 close(fd);
Damien Miller7b10ef42002-01-21 23:44:12 +1100217 return rval;
Damien Miller62116dc2001-12-24 01:41:47 +1100218}
219
220double
221stir_gettimeofday(double entropy_estimate)
222{
223 struct timeval tv;
224
225 if (gettimeofday(&tv, NULL) == -1)
226 fatal("Couldn't gettimeofday: %s", strerror(errno));
227
228 RAND_add(&tv, sizeof(tv), entropy_estimate);
229
Damien Miller7b10ef42002-01-21 23:44:12 +1100230 return entropy_estimate;
Damien Miller62116dc2001-12-24 01:41:47 +1100231}
232
233double
234stir_clock(double entropy_estimate)
235{
236#ifdef HAVE_CLOCK
237 clock_t c;
238
239 c = clock();
240 RAND_add(&c, sizeof(c), entropy_estimate);
241
Damien Miller7b10ef42002-01-21 23:44:12 +1100242 return entropy_estimate;
Damien Miller62116dc2001-12-24 01:41:47 +1100243#else /* _HAVE_CLOCK */
Damien Miller7b10ef42002-01-21 23:44:12 +1100244 return 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100245#endif /* _HAVE_CLOCK */
246}
247
248double
249stir_rusage(int who, double entropy_estimate)
250{
251#ifdef HAVE_GETRUSAGE
252 struct rusage ru;
253
254 if (getrusage(who, &ru) == -1)
Damien Miller7b10ef42002-01-21 23:44:12 +1100255 return 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100256
257 RAND_add(&ru, sizeof(ru), entropy_estimate);
258
Damien Miller7b10ef42002-01-21 23:44:12 +1100259 return entropy_estimate;
Damien Miller62116dc2001-12-24 01:41:47 +1100260#else /* _HAVE_GETRUSAGE */
Damien Miller7b10ef42002-01-21 23:44:12 +1100261 return 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100262#endif /* _HAVE_GETRUSAGE */
263}
264
Damien Miller62116dc2001-12-24 01:41:47 +1100265static int
Damien Miller7b10ef42002-01-21 23:44:12 +1100266timeval_diff(struct timeval *t1, struct timeval *t2)
267{
Damien Miller62116dc2001-12-24 01:41:47 +1100268 int secdiff, usecdiff;
269
270 secdiff = t2->tv_sec - t1->tv_sec;
271 usecdiff = (secdiff*1000000) + (t2->tv_usec - t1->tv_usec);
272 return (int)(usecdiff / 1000);
273}
274
275double
Kevin Steves4bdb5472002-07-28 20:42:23 +0000276hash_command_output(entropy_cmd_t *src, unsigned char *hash)
Damien Miller62116dc2001-12-24 01:41:47 +1100277{
Damien Miller7b10ef42002-01-21 23:44:12 +1100278 char buf[8192];
Damien Miller62116dc2001-12-24 01:41:47 +1100279 fd_set rdset;
Damien Miller7b10ef42002-01-21 23:44:12 +1100280 int bytes_read, cmd_eof, error_abort, msec_elapsed, p[2];
281 int status, total_bytes_read;
282 static int devnull = -1;
Damien Miller62116dc2001-12-24 01:41:47 +1100283 pid_t pid;
Damien Miller62116dc2001-12-24 01:41:47 +1100284 SHA_CTX sha;
Damien Miller7b10ef42002-01-21 23:44:12 +1100285 struct timeval tv_start, tv_current;
Damien Miller62116dc2001-12-24 01:41:47 +1100286
287 debug3("Reading output from \'%s\'", src->cmdstring);
288
289 if (devnull == -1) {
290 devnull = open("/dev/null", O_RDWR);
291 if (devnull == -1)
Damien Millera8e06ce2003-11-21 23:48:55 +1100292 fatal("Couldn't open /dev/null: %s",
Damien Miller7b10ef42002-01-21 23:44:12 +1100293 strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100294 }
295
296 if (pipe(p) == -1)
297 fatal("Couldn't open pipe: %s", strerror(errno));
298
299 (void)gettimeofday(&tv_start, NULL); /* record start time */
300
301 switch (pid = fork()) {
302 case -1: /* Error */
303 close(p[0]);
304 close(p[1]);
305 fatal("Couldn't fork: %s", strerror(errno));
306 /* NOTREACHED */
307 case 0: /* Child */
308 dup2(devnull, STDIN_FILENO);
309 dup2(p[1], STDOUT_FILENO);
310 dup2(p[1], STDERR_FILENO);
311 close(p[0]);
312 close(p[1]);
313 close(devnull);
314
315 execv(src->path, (char**)(src->args));
Damien Miller7b10ef42002-01-21 23:44:12 +1100316
Damien Millera8e06ce2003-11-21 23:48:55 +1100317 debug("(child) Couldn't exec '%s': %s",
Damien Miller7b10ef42002-01-21 23:44:12 +1100318 src->cmdstring, strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100319 _exit(-1);
320 default: /* Parent */
321 break;
322 }
323
324 RAND_add(&pid, sizeof(&pid), 0.0);
325
326 close(p[1]);
327
328 /* Hash output from child */
329 SHA1_Init(&sha);
Damien Miller62116dc2001-12-24 01:41:47 +1100330
Damien Miller7b10ef42002-01-21 23:44:12 +1100331 cmd_eof = error_abort = msec_elapsed = total_bytes_read = 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100332 while (!error_abort && !cmd_eof) {
333 int ret;
334 struct timeval tv;
335 int msec_remaining;
336
337 (void) gettimeofday(&tv_current, 0);
Damien Miller7b10ef42002-01-21 23:44:12 +1100338 msec_elapsed = timeval_diff(&tv_start, &tv_current);
Damien Miller62116dc2001-12-24 01:41:47 +1100339 if (msec_elapsed >= entropy_timeout_current) {
340 error_abort=1;
341 continue;
342 }
343 msec_remaining = entropy_timeout_current - msec_elapsed;
344
345 FD_ZERO(&rdset);
346 FD_SET(p[0], &rdset);
Damien Miller7b10ef42002-01-21 23:44:12 +1100347 tv.tv_sec = msec_remaining / 1000;
Damien Miller62116dc2001-12-24 01:41:47 +1100348 tv.tv_usec = (msec_remaining % 1000) * 1000;
349
Damien Miller7b10ef42002-01-21 23:44:12 +1100350 ret = select(p[0] + 1, &rdset, NULL, NULL, &tv);
Damien Miller62116dc2001-12-24 01:41:47 +1100351
352 RAND_add(&tv, sizeof(tv), 0.0);
353
354 switch (ret) {
355 case 0:
356 /* timer expired */
357 error_abort = 1;
Damien Miller5a5da882002-10-21 10:13:35 +1000358 kill(pid, SIGINT);
Damien Miller62116dc2001-12-24 01:41:47 +1100359 break;
360 case 1:
361 /* command input */
362 do {
363 bytes_read = read(p[0], buf, sizeof(buf));
364 } while (bytes_read == -1 && errno == EINTR);
365 RAND_add(&bytes_read, sizeof(&bytes_read), 0.0);
366 if (bytes_read == -1) {
367 error_abort = 1;
368 break;
369 } else if (bytes_read) {
370 SHA1_Update(&sha, buf, bytes_read);
371 total_bytes_read += bytes_read;
372 } else {
373 cmd_eof = 1;
374 }
375 break;
376 case -1:
377 default:
378 /* error */
Damien Millera8e06ce2003-11-21 23:48:55 +1100379 debug("Command '%s': select() failed: %s",
Damien Miller7b10ef42002-01-21 23:44:12 +1100380 src->cmdstring, strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100381 error_abort = 1;
382 break;
383 }
384 }
385
386 SHA1_Final(hash, &sha);
387
388 close(p[0]);
389
390 debug3("Time elapsed: %d msec", msec_elapsed);
391
392 if (waitpid(pid, &status, 0) == -1) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100393 error("Couldn't wait for child '%s' completion: %s",
Ben Lindstrom5a6abda2002-06-09 19:41:48 +0000394 src->cmdstring, strerror(errno));
Damien Miller7b10ef42002-01-21 23:44:12 +1100395 return 0.0;
Damien Miller62116dc2001-12-24 01:41:47 +1100396 }
397
398 RAND_add(&status, sizeof(&status), 0.0);
399
400 if (error_abort) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100401 /*
402 * Closing p[0] on timeout causes the entropy command to
Damien Millera8e06ce2003-11-21 23:48:55 +1100403 * SIGPIPE. Take whatever output we got, and mark this
404 * command as slow
Damien Miller7b10ef42002-01-21 23:44:12 +1100405 */
Damien Miller62116dc2001-12-24 01:41:47 +1100406 debug2("Command '%s' timed out", src->cmdstring);
407 src->sticky_badness *= 2;
408 src->badness = src->sticky_badness;
Damien Miller7b10ef42002-01-21 23:44:12 +1100409 return total_bytes_read;
Damien Miller62116dc2001-12-24 01:41:47 +1100410 }
411
412 if (WIFEXITED(status)) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100413 if (WEXITSTATUS(status) == 0) {
414 return total_bytes_read;
Damien Miller62116dc2001-12-24 01:41:47 +1100415 } else {
Damien Miller7b10ef42002-01-21 23:44:12 +1100416 debug2("Command '%s' exit status was %d",
417 src->cmdstring, WEXITSTATUS(status));
Damien Miller62116dc2001-12-24 01:41:47 +1100418 src->badness = src->sticky_badness = 128;
Damien Miller7b10ef42002-01-21 23:44:12 +1100419 return 0.0;
Damien Miller62116dc2001-12-24 01:41:47 +1100420 }
421 } else if (WIFSIGNALED(status)) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100422 debug2("Command '%s' returned on uncaught signal %d !",
423 src->cmdstring, status);
Damien Miller62116dc2001-12-24 01:41:47 +1100424 src->badness = src->sticky_badness = 128;
Damien Miller7b10ef42002-01-21 23:44:12 +1100425 return 0.0;
Damien Miller62116dc2001-12-24 01:41:47 +1100426 } else
Damien Miller7b10ef42002-01-21 23:44:12 +1100427 return 0.0;
428}
429
430double
431stir_from_system(void)
432{
433 double total_entropy_estimate;
434 long int i;
435
436 total_entropy_estimate = 0;
437
438 i = getpid();
439 RAND_add(&i, sizeof(i), 0.5);
440 total_entropy_estimate += 0.1;
441
442 i = getppid();
443 RAND_add(&i, sizeof(i), 0.5);
444 total_entropy_estimate += 0.1;
445
446 i = getuid();
447 RAND_add(&i, sizeof(i), 0.0);
448 i = getgid();
449 RAND_add(&i, sizeof(i), 0.0);
450
451 total_entropy_estimate += stir_gettimeofday(1.0);
452 total_entropy_estimate += stir_clock(0.5);
453 total_entropy_estimate += stir_rusage(RUSAGE_SELF, 2.0);
454
455 return total_entropy_estimate;
456}
457
458double
459stir_from_programs(void)
460{
461 int c;
462 double entropy, total_entropy;
Kevin Steves4bdb5472002-07-28 20:42:23 +0000463 unsigned char hash[SHA_DIGEST_LENGTH];
Damien Miller7b10ef42002-01-21 23:44:12 +1100464
465 total_entropy = 0;
466 for(c = 0; entropy_cmds[c].path != NULL; c++) {
467 if (!entropy_cmds[c].badness) {
468 /* Hash output from command */
469 entropy = hash_command_output(&entropy_cmds[c],
470 hash);
471
472 /* Scale back estimate by command's rate */
473 entropy *= entropy_cmds[c].rate;
474
475 /* Upper bound of entropy is SHA_DIGEST_LENGTH */
476 if (entropy > SHA_DIGEST_LENGTH)
477 entropy = SHA_DIGEST_LENGTH;
478
479 /* Stir it in */
480 RAND_add(hash, sizeof(hash), entropy);
481
Damien Millera8e06ce2003-11-21 23:48:55 +1100482 debug3("Got %0.2f bytes of entropy from '%s'",
Damien Miller7b10ef42002-01-21 23:44:12 +1100483 entropy, entropy_cmds[c].cmdstring);
484
485 total_entropy += entropy;
486
487 /* Execution time should be a bit unpredictable */
488 total_entropy += stir_gettimeofday(0.05);
489 total_entropy += stir_clock(0.05);
490 total_entropy += stir_rusage(RUSAGE_SELF, 0.1);
491 total_entropy += stir_rusage(RUSAGE_CHILDREN, 0.1);
492 } else {
493 debug2("Command '%s' disabled (badness %d)",
Damien Millera8e06ce2003-11-21 23:48:55 +1100494 entropy_cmds[c].cmdstring,
Damien Miller7b10ef42002-01-21 23:44:12 +1100495 entropy_cmds[c].badness);
496
497 if (entropy_cmds[c].badness > 0)
498 entropy_cmds[c].badness--;
499 }
500 }
501
502 return total_entropy;
Damien Miller62116dc2001-12-24 01:41:47 +1100503}
504
505/*
506 * prng seedfile functions
507 */
508int
Damien Miller7b10ef42002-01-21 23:44:12 +1100509prng_check_seedfile(char *filename)
510{
Damien Miller62116dc2001-12-24 01:41:47 +1100511 struct stat st;
512
Damien Miller7b10ef42002-01-21 23:44:12 +1100513 /*
Damien Millera8e06ce2003-11-21 23:48:55 +1100514 * XXX raceable: eg replace seed between this stat and subsequent
515 * open. Not such a problem because we don't really trust the
Damien Miller7b10ef42002-01-21 23:44:12 +1100516 * seed file anyway.
517 * XXX: use secure path checking as elsewhere in OpenSSH
518 */
Damien Miller62116dc2001-12-24 01:41:47 +1100519 if (lstat(filename, &st) == -1) {
520 /* Give up on hard errors */
521 if (errno != ENOENT)
Damien Miller7b10ef42002-01-21 23:44:12 +1100522 debug("WARNING: Couldn't stat random seed file "
523 "\"%.100s\": %s", filename, strerror(errno));
524 return 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100525 }
526
527 /* regular file? */
528 if (!S_ISREG(st.st_mode))
Damien Miller7b10ef42002-01-21 23:44:12 +1100529 fatal("PRNG seedfile %.100s is not a regular file",
530 filename);
Damien Miller62116dc2001-12-24 01:41:47 +1100531
532 /* mode 0600, owned by root or the current user? */
533 if (((st.st_mode & 0177) != 0) || !(st.st_uid == getuid())) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100534 debug("WARNING: PRNG seedfile %.100s must be mode 0600, "
Damien Millerc46b6bc2003-05-16 15:51:44 +1000535 "owned by uid %li", filename, (long int)getuid());
Damien Miller7b10ef42002-01-21 23:44:12 +1100536 return 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100537 }
538
Damien Miller7b10ef42002-01-21 23:44:12 +1100539 return 1;
Damien Miller62116dc2001-12-24 01:41:47 +1100540}
541
542void
Damien Miller7b10ef42002-01-21 23:44:12 +1100543prng_write_seedfile(void)
544{
Damien Miller62116dc2001-12-24 01:41:47 +1100545 int fd;
Kevin Steves4bdb5472002-07-28 20:42:23 +0000546 unsigned char seed[SEED_FILE_SIZE];
547 char filename[MAXPATHLEN];
Damien Miller62116dc2001-12-24 01:41:47 +1100548 struct passwd *pw;
549
550 pw = getpwuid(getuid());
551 if (pw == NULL)
Damien Miller7b10ef42002-01-21 23:44:12 +1100552 fatal("Couldn't get password entry for current user "
Damien Millerc46b6bc2003-05-16 15:51:44 +1000553 "(%li): %s", (long int)getuid(), strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100554
555 /* Try to ensure that the parent directory is there */
556 snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir,
Damien Miller7b10ef42002-01-21 23:44:12 +1100557 _PATH_SSH_USER_DIR);
Damien Miller62116dc2001-12-24 01:41:47 +1100558 mkdir(filename, 0700);
559
560 snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir,
Damien Miller7b10ef42002-01-21 23:44:12 +1100561 SSH_PRNG_SEED_FILE);
Damien Miller62116dc2001-12-24 01:41:47 +1100562
563 debug("writing PRNG seed to file %.100s", filename);
564
Damien Millercafbcc72003-03-17 16:13:53 +1100565 if (RAND_bytes(seed, sizeof(seed)) <= 0)
Ben Lindstromda4d9cf2003-09-22 15:36:15 +0000566 fatal("PRNG seed extraction failed");
Damien Miller62116dc2001-12-24 01:41:47 +1100567
568 /* Don't care if the seed doesn't exist */
569 prng_check_seedfile(filename);
570
571 if ((fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0600)) == -1) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100572 debug("WARNING: couldn't access PRNG seedfile %.100s "
573 "(%.100s)", filename, strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100574 } else {
Darren Tucker8661b562003-07-06 15:20:46 +1000575 if (atomicio(vwrite, fd, &seed, sizeof(seed)) < sizeof(seed))
Damien Miller7b10ef42002-01-21 23:44:12 +1100576 fatal("problem writing PRNG seedfile %.100s "
577 "(%.100s)", filename, strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100578 close(fd);
579 }
580}
581
582void
Damien Miller7b10ef42002-01-21 23:44:12 +1100583prng_read_seedfile(void)
584{
Damien Miller62116dc2001-12-24 01:41:47 +1100585 int fd;
Damien Miller7b10ef42002-01-21 23:44:12 +1100586 char seed[SEED_FILE_SIZE], filename[MAXPATHLEN];
Damien Miller62116dc2001-12-24 01:41:47 +1100587 struct passwd *pw;
588
589 pw = getpwuid(getuid());
590 if (pw == NULL)
Damien Miller7b10ef42002-01-21 23:44:12 +1100591 fatal("Couldn't get password entry for current user "
Damien Millerc46b6bc2003-05-16 15:51:44 +1000592 "(%li): %s", (long int)getuid(), strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100593
594 snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir,
595 SSH_PRNG_SEED_FILE);
596
597 debug("loading PRNG seed from file %.100s", filename);
598
599 if (!prng_check_seedfile(filename)) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100600 verbose("Random seed file not found or invalid, ignoring.");
Damien Miller62116dc2001-12-24 01:41:47 +1100601 return;
602 }
603
604 /* open the file and read in the seed */
605 fd = open(filename, O_RDONLY);
606 if (fd == -1)
Damien Miller7b10ef42002-01-21 23:44:12 +1100607 fatal("could not open PRNG seedfile %.100s (%.100s)",
608 filename, strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100609
Damien Miller7b10ef42002-01-21 23:44:12 +1100610 if (atomicio(read, fd, &seed, sizeof(seed)) < sizeof(seed)) {
611 verbose("invalid or short read from PRNG seedfile "
612 "%.100s - ignoring", filename);
Damien Miller62116dc2001-12-24 01:41:47 +1100613 memset(seed, '\0', sizeof(seed));
614 }
615 close(fd);
616
617 /* stir in the seed, with estimated entropy zero */
618 RAND_add(&seed, sizeof(seed), 0.0);
619}
620
621
622/*
623 * entropy command initialisation functions
624 */
625int
626prng_read_commands(char *cmdfilename)
627{
Damien Miller7b10ef42002-01-21 23:44:12 +1100628 char cmd[SEED_FILE_SIZE], *cp, line[1024], path[SEED_FILE_SIZE];
Damien Miller62116dc2001-12-24 01:41:47 +1100629 double est;
Damien Miller7b10ef42002-01-21 23:44:12 +1100630 entropy_cmd_t *entcmd;
631 FILE *f;
632 int cur_cmd, linenum, num_cmds, arg;
Damien Miller62116dc2001-12-24 01:41:47 +1100633
Damien Miller7b10ef42002-01-21 23:44:12 +1100634 if ((f = fopen(cmdfilename, "r")) == NULL) {
Damien Miller62116dc2001-12-24 01:41:47 +1100635 fatal("couldn't read entropy commands file %.100s: %.100s",
636 cmdfilename, strerror(errno));
637 }
638
Damien Miller7b10ef42002-01-21 23:44:12 +1100639 num_cmds = 64;
640 entcmd = xmalloc(num_cmds * sizeof(entropy_cmd_t));
641 memset(entcmd, '\0', num_cmds * sizeof(entropy_cmd_t));
Damien Miller62116dc2001-12-24 01:41:47 +1100642
643 /* Read in file */
Damien Miller7b10ef42002-01-21 23:44:12 +1100644 cur_cmd = linenum = 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100645 while (fgets(line, sizeof(line), f)) {
Damien Miller62116dc2001-12-24 01:41:47 +1100646 linenum++;
647
Damien Miller7b10ef42002-01-21 23:44:12 +1100648 /* Skip leading whitespace, blank lines and comments */
Damien Miller62116dc2001-12-24 01:41:47 +1100649 cp = line + strspn(line, WHITESPACE);
650 if ((*cp == 0) || (*cp == '#'))
651 continue; /* done with this line */
652
Damien Miller7b10ef42002-01-21 23:44:12 +1100653 /*
Damien Millera8e06ce2003-11-21 23:48:55 +1100654 * The first non-whitespace char should be a double quote
Damien Miller7b10ef42002-01-21 23:44:12 +1100655 * delimiting the commandline
656 */
Damien Miller62116dc2001-12-24 01:41:47 +1100657 if (*cp != '"') {
Damien Miller7b10ef42002-01-21 23:44:12 +1100658 error("bad entropy command, %.100s line %d",
659 cmdfilename, linenum);
Damien Miller62116dc2001-12-24 01:41:47 +1100660 continue;
661 }
662
Damien Miller7b10ef42002-01-21 23:44:12 +1100663 /*
664 * First token, command args (incl. argv[0]) in double
665 * quotes
666 */
Damien Miller62116dc2001-12-24 01:41:47 +1100667 cp = strtok(cp, "\"");
668 if (cp == NULL) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100669 error("missing or bad command string, %.100s "
670 "line %d -- ignored", cmdfilename, linenum);
Damien Miller62116dc2001-12-24 01:41:47 +1100671 continue;
672 }
673 strlcpy(cmd, cp, sizeof(cmd));
674
Damien Miller7b10ef42002-01-21 23:44:12 +1100675 /* Second token, full command path */
Damien Miller62116dc2001-12-24 01:41:47 +1100676 if ((cp = strtok(NULL, WHITESPACE)) == NULL) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100677 error("missing command path, %.100s "
678 "line %d -- ignored", cmdfilename, linenum);
Damien Miller62116dc2001-12-24 01:41:47 +1100679 continue;
680 }
681
Damien Miller7b10ef42002-01-21 23:44:12 +1100682 /* Did configure mark this as dead? */
Damien Miller62116dc2001-12-24 01:41:47 +1100683 if (strncmp("undef", cp, 5) == 0)
684 continue;
685
686 strlcpy(path, cp, sizeof(path));
687
Damien Miller7b10ef42002-01-21 23:44:12 +1100688 /* Third token, entropy rate estimate for this command */
Damien Miller62116dc2001-12-24 01:41:47 +1100689 if ((cp = strtok(NULL, WHITESPACE)) == NULL) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100690 error("missing entropy estimate, %.100s "
691 "line %d -- ignored", cmdfilename, linenum);
Damien Miller62116dc2001-12-24 01:41:47 +1100692 continue;
693 }
Damien Miller7b10ef42002-01-21 23:44:12 +1100694 est = strtod(cp, NULL);
Damien Miller62116dc2001-12-24 01:41:47 +1100695
696 /* end of line */
697 if ((cp = strtok(NULL, WHITESPACE)) != NULL) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100698 error("garbage at end of line %d in %.100s "
699 "-- ignored", linenum, cmdfilename);
Damien Miller62116dc2001-12-24 01:41:47 +1100700 continue;
701 }
702
703 /* save the command for debug messages */
704 entcmd[cur_cmd].cmdstring = xstrdup(cmd);
705
706 /* split the command args */
707 cp = strtok(cmd, WHITESPACE);
708 arg = 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100709 do {
Damien Miller7b10ef42002-01-21 23:44:12 +1100710 entcmd[cur_cmd].args[arg] = xstrdup(cp);
Damien Miller62116dc2001-12-24 01:41:47 +1100711 arg++;
Damien Miller7b10ef42002-01-21 23:44:12 +1100712 } while(arg < NUM_ARGS && (cp = strtok(NULL, WHITESPACE)));
Damien Miller62116dc2001-12-24 01:41:47 +1100713
714 if (strtok(NULL, WHITESPACE))
Damien Miller7b10ef42002-01-21 23:44:12 +1100715 error("ignored extra commands (max %d), %.100s "
716 "line %d", NUM_ARGS, cmdfilename, linenum);
Damien Miller62116dc2001-12-24 01:41:47 +1100717
718 /* Copy the command path and rate estimate */
719 entcmd[cur_cmd].path = xstrdup(path);
720 entcmd[cur_cmd].rate = est;
721
722 /* Initialise other values */
723 entcmd[cur_cmd].sticky_badness = 1;
724
725 cur_cmd++;
726
Damien Miller7b10ef42002-01-21 23:44:12 +1100727 /*
728 * If we've filled the array, reallocate it twice the size
Damien Millera8e06ce2003-11-21 23:48:55 +1100729 * Do this now because even if this we're on the last
Damien Miller7b10ef42002-01-21 23:44:12 +1100730 * command we need another slot to mark the last entry
731 */
Damien Miller62116dc2001-12-24 01:41:47 +1100732 if (cur_cmd == num_cmds) {
733 num_cmds *= 2;
Damien Miller7b10ef42002-01-21 23:44:12 +1100734 entcmd = xrealloc(entcmd, num_cmds *
735 sizeof(entropy_cmd_t));
Damien Miller62116dc2001-12-24 01:41:47 +1100736 }
737 }
738
739 /* zero the last entry */
Damien Miller7b10ef42002-01-21 23:44:12 +1100740 memset(&entcmd[cur_cmd], '\0', sizeof(entropy_cmd_t));
Damien Miller62116dc2001-12-24 01:41:47 +1100741
742 /* trim to size */
Damien Miller7b10ef42002-01-21 23:44:12 +1100743 entropy_cmds = xrealloc(entcmd, (cur_cmd + 1) *
744 sizeof(entropy_cmd_t));
Damien Miller62116dc2001-12-24 01:41:47 +1100745
Damien Miller7b10ef42002-01-21 23:44:12 +1100746 debug("Loaded %d entropy commands from %.100s", cur_cmd,
747 cmdfilename);
Damien Miller62116dc2001-12-24 01:41:47 +1100748
Damien Miller7b10ef42002-01-21 23:44:12 +1100749 return cur_cmd < MIN_ENTROPY_SOURCES ? -1 : 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100750}
751
Damien Miller32e48182002-04-14 19:27:12 +1000752void
753usage(void)
754{
755 fprintf(stderr, "Usage: %s [options]\n", __progname);
756 fprintf(stderr, " -v Verbose; display verbose debugging messages.\n");
757 fprintf(stderr, " Multiple -v increases verbosity.\n");
758 fprintf(stderr, " -x Force output in hexidecimal (for debugging)\n");
759 fprintf(stderr, " -X Force output in binary\n");
760 fprintf(stderr, " -b bytes Number of bytes to output (default %d)\n",
761 OUTPUT_SEED_SIZE);
762}
763
Damien Millera8e06ce2003-11-21 23:48:55 +1100764int
Damien Miller62116dc2001-12-24 01:41:47 +1100765main(int argc, char **argv)
766{
Damien Miller32e48182002-04-14 19:27:12 +1000767 unsigned char *buf;
768 int ret, ch, debug_level, output_hex, bytes;
769 extern char *optarg;
770 LogLevel ll;
Damien Miller62116dc2001-12-24 01:41:47 +1100771
Damien Miller59d3d5b2003-08-22 09:34:41 +1000772 __progname = ssh_get_progname(argv[0]);
Damien Miller62116dc2001-12-24 01:41:47 +1100773 log_init(argv[0], SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_USER, 1);
774
Damien Miller32e48182002-04-14 19:27:12 +1000775 ll = SYSLOG_LEVEL_INFO;
776 debug_level = output_hex = 0;
777 bytes = OUTPUT_SEED_SIZE;
778
779 /* Don't write binary data to a tty, unless we are forced to */
780 if (isatty(STDOUT_FILENO))
781 output_hex = 1;
Damien Miller787b2ec2003-11-21 23:56:47 +1100782
Damien Miller32e48182002-04-14 19:27:12 +1000783 while ((ch = getopt(argc, argv, "vxXhb:")) != -1) {
784 switch (ch) {
785 case 'v':
786 if (debug_level < 3)
787 ll = SYSLOG_LEVEL_DEBUG1 + debug_level++;
788 break;
789 case 'x':
790 output_hex = 1;
791 break;
792 case 'X':
793 output_hex = 0;
794 break;
795 case 'b':
796 if ((bytes = atoi(optarg)) <= 0)
797 fatal("Invalid number of output bytes");
798 break;
799 case 'h':
800 usage();
801 exit(0);
802 default:
803 error("Invalid commandline option");
804 usage();
805 }
806 }
807
808 log_init(argv[0], ll, SYSLOG_FACILITY_USER, 1);
Damien Miller787b2ec2003-11-21 23:56:47 +1100809
Damien Miller7b10ef42002-01-21 23:44:12 +1100810#ifdef USE_SEED_FILES
811 prng_read_seedfile();
812#endif
813
Damien Miller32e48182002-04-14 19:27:12 +1000814 buf = xmalloc(bytes);
815
Damien Miller7b10ef42002-01-21 23:44:12 +1100816 /*
817 * Seed the RNG from wherever we can
818 */
Damien Miller787b2ec2003-11-21 23:56:47 +1100819
Damien Miller7b10ef42002-01-21 23:44:12 +1100820 /* Take whatever is on the stack, but don't credit it */
Damien Miller32e48182002-04-14 19:27:12 +1000821 RAND_add(buf, bytes, 0);
Damien Miller7b10ef42002-01-21 23:44:12 +1100822
Damien Millera8e06ce2003-11-21 23:48:55 +1100823 debug("Seeded RNG with %i bytes from system calls",
Damien Miller7b10ef42002-01-21 23:44:12 +1100824 (int)stir_from_system());
825
826#ifdef PRNGD_PORT
Damien Miller32e48182002-04-14 19:27:12 +1000827 if (get_random_bytes_prngd(buf, bytes, PRNGD_PORT, NULL) == -1)
Damien Miller7b10ef42002-01-21 23:44:12 +1100828 fatal("Entropy collection failed");
Damien Miller32e48182002-04-14 19:27:12 +1000829 RAND_add(buf, bytes, bytes);
Damien Millerc46cc542002-01-22 21:58:27 +1100830#elif defined(PRNGD_SOCKET)
Damien Miller32e48182002-04-14 19:27:12 +1000831 if (get_random_bytes_prngd(buf, bytes, 0, PRNGD_SOCKET) == -1)
Damien Miller7b10ef42002-01-21 23:44:12 +1100832 fatal("Entropy collection failed");
Damien Miller32e48182002-04-14 19:27:12 +1000833 RAND_add(buf, bytes, bytes);
Damien Miller7b10ef42002-01-21 23:44:12 +1100834#else
835 /* Read in collection commands */
836 if (prng_read_commands(SSH_PRNG_COMMAND_FILE) == -1)
837 fatal("PRNG initialisation failed -- exiting.");
Damien Millera8e06ce2003-11-21 23:48:55 +1100838 debug("Seeded RNG with %i bytes from programs",
Damien Miller7b10ef42002-01-21 23:44:12 +1100839 (int)stir_from_programs());
840#endif
841
842#ifdef USE_SEED_FILES
843 prng_write_seedfile();
844#endif
845
846 /*
847 * Write the seed to stdout
848 */
Damien Miller62116dc2001-12-24 01:41:47 +1100849
850 if (!RAND_status())
851 fatal("Not enough entropy in RNG");
852
Damien Millercafbcc72003-03-17 16:13:53 +1100853 if (RAND_bytes(buf, bytes) <= 0)
854 fatal("Couldn't extract entropy from PRNG");
Damien Miller62116dc2001-12-24 01:41:47 +1100855
Damien Miller32e48182002-04-14 19:27:12 +1000856 if (output_hex) {
857 for(ret = 0; ret < bytes; ret++)
858 printf("%02x", (unsigned char)(buf[ret]));
859 printf("\n");
860 } else
Darren Tucker8661b562003-07-06 15:20:46 +1000861 ret = atomicio(vwrite, STDOUT_FILENO, buf, bytes);
Damien Miller787b2ec2003-11-21 23:56:47 +1100862
Damien Miller32e48182002-04-14 19:27:12 +1000863 memset(buf, '\0', bytes);
864 xfree(buf);
Damien Miller787b2ec2003-11-21 23:56:47 +1100865
Damien Miller32e48182002-04-14 19:27:12 +1000866 return ret == bytes ? 0 : 1;
Damien Miller62116dc2001-12-24 01:41:47 +1100867}