blob: 07856e5c3f934c2e578bb4afd1835785a76c72a5 [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 Miller05eda432002-02-10 18:32:28 +110042RCSID("$Id: ssh-rand-helper.c,v 1.5 2002/02/10 07:32:30 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
66
Kevin Steves94435082001-12-25 04:32:58 +000067#ifdef HAVE___PROGNAME
68extern char *__progname;
69#else
70char *__progname;
71#endif
72
Damien Miller62116dc2001-12-24 01:41:47 +110073#ifndef offsetof
74# define offsetof(type, member) ((size_t) &((type *)0)->member)
75#endif
76
Damien Miller62116dc2001-12-24 01:41:47 +110077#define WHITESPACE " \t\n"
78
79#ifndef RUSAGE_SELF
80# define RUSAGE_SELF 0
81#endif
82#ifndef RUSAGE_CHILDREN
83# define RUSAGE_CHILDREN 0
84#endif
85
Damien Millerc46cc542002-01-22 21:58:27 +110086#if !defined(PRNGD_SOCKET) && !defined(PRNGD_PORT)
Damien Miller7b10ef42002-01-21 23:44:12 +110087# define USE_SEED_FILES
Damien Miller62116dc2001-12-24 01:41:47 +110088#endif
89
Damien Miller7b10ef42002-01-21 23:44:12 +110090typedef struct {
91 /* Proportion of data that is entropy */
92 double rate;
93 /* Counter goes positive if this command times out */
94 unsigned int badness;
95 /* Increases by factor of two each timeout */
96 unsigned int sticky_badness;
97 /* Path to executable */
98 char *path;
99 /* argv to pass to executable */
100 char *args[NUM_ARGS]; /* XXX: arbitrary limit */
101 /* full command string (debug) */
102 char *cmdstring;
103} entropy_cmd_t;
104
105/* slow command timeouts (all in milliseconds) */
106/* static int entropy_timeout_default = ENTROPY_TIMEOUT_MSEC; */
107static int entropy_timeout_current = ENTROPY_TIMEOUT_MSEC;
108
109/* this is initialised from a file, by prng_read_commands() */
110static entropy_cmd_t *entropy_cmds = NULL;
111
112/* Prototypes */
113double stir_from_system(void);
114double stir_from_programs(void);
115double stir_gettimeofday(double entropy_estimate);
116double stir_clock(double entropy_estimate);
117double stir_rusage(int who, double entropy_estimate);
118double hash_command_output(entropy_cmd_t *src, char *hash);
119int get_random_bytes_prngd(unsigned char *buf, int len,
120 unsigned short tcp_port, char *socket_path);
121
122/*
123 * Collect 'len' bytes of entropy into 'buf' from PRNGD/EGD daemon
124 * listening either on 'tcp_port', or via Unix domain socket at *
125 * 'socket_path'.
126 * Either a non-zero tcp_port or a non-null socket_path must be
127 * supplied.
128 * Returns 0 on success, -1 on error
129 */
Damien Miller62116dc2001-12-24 01:41:47 +1100130int
Damien Miller7b10ef42002-01-21 23:44:12 +1100131get_random_bytes_prngd(unsigned char *buf, int len,
132 unsigned short tcp_port, char *socket_path)
Damien Miller62116dc2001-12-24 01:41:47 +1100133{
Damien Miller7b10ef42002-01-21 23:44:12 +1100134 int fd, addr_len, rval, errors;
Damien Miller62116dc2001-12-24 01:41:47 +1100135 char msg[2];
Damien Miller7b10ef42002-01-21 23:44:12 +1100136 struct sockaddr_storage addr;
137 struct sockaddr_in *addr_in = (struct sockaddr_in *)&addr;
138 struct sockaddr_un *addr_un = (struct sockaddr_un *)&addr;
Damien Miller62116dc2001-12-24 01:41:47 +1100139 mysig_t old_sigpipe;
140
Damien Miller7b10ef42002-01-21 23:44:12 +1100141 /* Sanity checks */
142 if (socket_path == NULL && tcp_port == 0)
143 fatal("You must specify a port or a socket");
144 if (socket_path != NULL &&
145 strlen(socket_path) >= sizeof(addr_un->sun_path))
146 fatal("Random pool path is too long");
Damien Miller62116dc2001-12-24 01:41:47 +1100147 if (len > 255)
148 fatal("Too many bytes to read from PRNGD");
149
150 memset(&addr, '\0', sizeof(addr));
151
Damien Miller7b10ef42002-01-21 23:44:12 +1100152 if (tcp_port != 0) {
153 addr_in->sin_family = AF_INET;
154 addr_in->sin_addr.s_addr = htonl(INADDR_LOOPBACK);
155 addr_in->sin_port = htons(tcp_port);
156 addr_len = sizeof(*addr_in);
157 } else {
158 addr_un->sun_family = AF_UNIX;
159 strlcpy(addr_un->sun_path, socket_path,
160 sizeof(addr_un->sun_path));
161 addr_len = offsetof(struct sockaddr_un, sun_path) +
162 strlen(socket_path) + 1;
163 }
Damien Miller62116dc2001-12-24 01:41:47 +1100164
165 old_sigpipe = mysignal(SIGPIPE, SIG_IGN);
166
Damien Miller7b10ef42002-01-21 23:44:12 +1100167 errors = 0;
168 rval = -1;
Damien Miller62116dc2001-12-24 01:41:47 +1100169reopen:
Damien Miller7b10ef42002-01-21 23:44:12 +1100170 fd = socket(addr.ss_family, SOCK_STREAM, 0);
Damien Miller62116dc2001-12-24 01:41:47 +1100171 if (fd == -1) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100172 error("Couldn't create socket: %s", strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100173 goto done;
174 }
Damien Miller62116dc2001-12-24 01:41:47 +1100175
176 if (connect(fd, (struct sockaddr*)&addr, addr_len) == -1) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100177 if (tcp_port != 0) {
178 error("Couldn't connect to PRNGD port %d: %s",
179 tcp_port, strerror(errno));
180 } else {
181 error("Couldn't connect to PRNGD socket \"%s\": %s",
182 addr_un->sun_path, strerror(errno));
183 }
Damien Miller62116dc2001-12-24 01:41:47 +1100184 goto done;
185 }
186
187 /* Send blocking read request to PRNGD */
188 msg[0] = 0x02;
189 msg[1] = len;
190
191 if (atomicio(write, fd, msg, sizeof(msg)) != sizeof(msg)) {
192 if (errno == EPIPE && errors < 10) {
193 close(fd);
194 errors++;
195 goto reopen;
196 }
197 error("Couldn't write to PRNGD socket: %s",
198 strerror(errno));
199 goto done;
200 }
201
202 if (atomicio(read, fd, buf, len) != len) {
203 if (errno == EPIPE && errors < 10) {
204 close(fd);
205 errors++;
206 goto reopen;
207 }
208 error("Couldn't read from PRNGD socket: %s",
209 strerror(errno));
210 goto done;
211 }
212
Damien Miller7b10ef42002-01-21 23:44:12 +1100213 rval = 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100214done:
215 mysignal(SIGPIPE, old_sigpipe);
216 if (fd != -1)
217 close(fd);
Damien Miller7b10ef42002-01-21 23:44:12 +1100218 return rval;
Damien Miller62116dc2001-12-24 01:41:47 +1100219}
220
221double
222stir_gettimeofday(double entropy_estimate)
223{
224 struct timeval tv;
225
226 if (gettimeofday(&tv, NULL) == -1)
227 fatal("Couldn't gettimeofday: %s", strerror(errno));
228
229 RAND_add(&tv, sizeof(tv), entropy_estimate);
230
Damien Miller7b10ef42002-01-21 23:44:12 +1100231 return entropy_estimate;
Damien Miller62116dc2001-12-24 01:41:47 +1100232}
233
234double
235stir_clock(double entropy_estimate)
236{
237#ifdef HAVE_CLOCK
238 clock_t c;
239
240 c = clock();
241 RAND_add(&c, sizeof(c), entropy_estimate);
242
Damien Miller7b10ef42002-01-21 23:44:12 +1100243 return entropy_estimate;
Damien Miller62116dc2001-12-24 01:41:47 +1100244#else /* _HAVE_CLOCK */
Damien Miller7b10ef42002-01-21 23:44:12 +1100245 return 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100246#endif /* _HAVE_CLOCK */
247}
248
249double
250stir_rusage(int who, double entropy_estimate)
251{
252#ifdef HAVE_GETRUSAGE
253 struct rusage ru;
254
255 if (getrusage(who, &ru) == -1)
Damien Miller7b10ef42002-01-21 23:44:12 +1100256 return 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100257
258 RAND_add(&ru, sizeof(ru), entropy_estimate);
259
Damien Miller7b10ef42002-01-21 23:44:12 +1100260 return entropy_estimate;
Damien Miller62116dc2001-12-24 01:41:47 +1100261#else /* _HAVE_GETRUSAGE */
Damien Miller7b10ef42002-01-21 23:44:12 +1100262 return 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100263#endif /* _HAVE_GETRUSAGE */
264}
265
Damien Miller62116dc2001-12-24 01:41:47 +1100266static int
Damien Miller7b10ef42002-01-21 23:44:12 +1100267timeval_diff(struct timeval *t1, struct timeval *t2)
268{
Damien Miller62116dc2001-12-24 01:41:47 +1100269 int secdiff, usecdiff;
270
271 secdiff = t2->tv_sec - t1->tv_sec;
272 usecdiff = (secdiff*1000000) + (t2->tv_usec - t1->tv_usec);
273 return (int)(usecdiff / 1000);
274}
275
276double
Damien Miller7b10ef42002-01-21 23:44:12 +1100277hash_command_output(entropy_cmd_t *src, char *hash)
Damien Miller62116dc2001-12-24 01:41:47 +1100278{
Damien Miller7b10ef42002-01-21 23:44:12 +1100279 char buf[8192];
Damien Miller62116dc2001-12-24 01:41:47 +1100280 fd_set rdset;
Damien Miller7b10ef42002-01-21 23:44:12 +1100281 int bytes_read, cmd_eof, error_abort, msec_elapsed, p[2];
282 int status, total_bytes_read;
283 static int devnull = -1;
Damien Miller62116dc2001-12-24 01:41:47 +1100284 pid_t pid;
Damien Miller62116dc2001-12-24 01:41:47 +1100285 SHA_CTX sha;
Damien Miller7b10ef42002-01-21 23:44:12 +1100286 struct timeval tv_start, tv_current;
Damien Miller62116dc2001-12-24 01:41:47 +1100287
288 debug3("Reading output from \'%s\'", src->cmdstring);
289
290 if (devnull == -1) {
291 devnull = open("/dev/null", O_RDWR);
292 if (devnull == -1)
Damien Miller7b10ef42002-01-21 23:44:12 +1100293 fatal("Couldn't open /dev/null: %s",
294 strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100295 }
296
297 if (pipe(p) == -1)
298 fatal("Couldn't open pipe: %s", strerror(errno));
299
300 (void)gettimeofday(&tv_start, NULL); /* record start time */
301
302 switch (pid = fork()) {
303 case -1: /* Error */
304 close(p[0]);
305 close(p[1]);
306 fatal("Couldn't fork: %s", strerror(errno));
307 /* NOTREACHED */
308 case 0: /* Child */
309 dup2(devnull, STDIN_FILENO);
310 dup2(p[1], STDOUT_FILENO);
311 dup2(p[1], STDERR_FILENO);
312 close(p[0]);
313 close(p[1]);
314 close(devnull);
315
316 execv(src->path, (char**)(src->args));
Damien Miller7b10ef42002-01-21 23:44:12 +1100317
318 debug("(child) Couldn't exec '%s': %s",
319 src->cmdstring, strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100320 _exit(-1);
321 default: /* Parent */
322 break;
323 }
324
325 RAND_add(&pid, sizeof(&pid), 0.0);
326
327 close(p[1]);
328
329 /* Hash output from child */
330 SHA1_Init(&sha);
Damien Miller62116dc2001-12-24 01:41:47 +1100331
Damien Miller7b10ef42002-01-21 23:44:12 +1100332 cmd_eof = error_abort = msec_elapsed = total_bytes_read = 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100333 while (!error_abort && !cmd_eof) {
334 int ret;
335 struct timeval tv;
336 int msec_remaining;
337
338 (void) gettimeofday(&tv_current, 0);
Damien Miller7b10ef42002-01-21 23:44:12 +1100339 msec_elapsed = timeval_diff(&tv_start, &tv_current);
Damien Miller62116dc2001-12-24 01:41:47 +1100340 if (msec_elapsed >= entropy_timeout_current) {
341 error_abort=1;
342 continue;
343 }
344 msec_remaining = entropy_timeout_current - msec_elapsed;
345
346 FD_ZERO(&rdset);
347 FD_SET(p[0], &rdset);
Damien Miller7b10ef42002-01-21 23:44:12 +1100348 tv.tv_sec = msec_remaining / 1000;
Damien Miller62116dc2001-12-24 01:41:47 +1100349 tv.tv_usec = (msec_remaining % 1000) * 1000;
350
Damien Miller7b10ef42002-01-21 23:44:12 +1100351 ret = select(p[0] + 1, &rdset, NULL, NULL, &tv);
Damien Miller62116dc2001-12-24 01:41:47 +1100352
353 RAND_add(&tv, sizeof(tv), 0.0);
354
355 switch (ret) {
356 case 0:
357 /* timer expired */
358 error_abort = 1;
359 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 Miller7b10ef42002-01-21 23:44:12 +1100379 debug("Command '%s': select() failed: %s",
380 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",
394 src->cmdstring, strerror(errno));
395 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
403 * SIGPIPE. Take whatever output we got, and mark this
404 * command as slow
405 */
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;
463 char hash[SHA_DIGEST_LENGTH];
464
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
482 debug3("Got %0.2f bytes of entropy from '%s'",
483 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)",
494 entropy_cmds[c].cmdstring,
495 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 /*
514 * XXX raceable: eg replace seed between this stat and subsequent
515 * open. Not such a problem because we don't really trust the
516 * 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, "
535 "owned by uid %d", filename, getuid());
536 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;
Damien Miller7b10ef42002-01-21 23:44:12 +1100546 char seed[SEED_FILE_SIZE], filename[MAXPATHLEN];
Damien Miller62116dc2001-12-24 01:41:47 +1100547 struct passwd *pw;
548
549 pw = getpwuid(getuid());
550 if (pw == NULL)
Damien Miller7b10ef42002-01-21 23:44:12 +1100551 fatal("Couldn't get password entry for current user "
552 "(%i): %s", getuid(), strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100553
554 /* Try to ensure that the parent directory is there */
555 snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir,
Damien Miller7b10ef42002-01-21 23:44:12 +1100556 _PATH_SSH_USER_DIR);
Damien Miller62116dc2001-12-24 01:41:47 +1100557 mkdir(filename, 0700);
558
559 snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir,
Damien Miller7b10ef42002-01-21 23:44:12 +1100560 SSH_PRNG_SEED_FILE);
Damien Miller62116dc2001-12-24 01:41:47 +1100561
562 debug("writing PRNG seed to file %.100s", filename);
563
564 RAND_bytes(seed, sizeof(seed));
565
566 /* Don't care if the seed doesn't exist */
567 prng_check_seedfile(filename);
568
569 if ((fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0600)) == -1) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100570 debug("WARNING: couldn't access PRNG seedfile %.100s "
571 "(%.100s)", filename, strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100572 } else {
Damien Miller7b10ef42002-01-21 23:44:12 +1100573 if (atomicio(write, fd, &seed, sizeof(seed)) < sizeof(seed))
574 fatal("problem writing PRNG seedfile %.100s "
575 "(%.100s)", filename, strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100576 close(fd);
577 }
578}
579
580void
Damien Miller7b10ef42002-01-21 23:44:12 +1100581prng_read_seedfile(void)
582{
Damien Miller62116dc2001-12-24 01:41:47 +1100583 int fd;
Damien Miller7b10ef42002-01-21 23:44:12 +1100584 char seed[SEED_FILE_SIZE], filename[MAXPATHLEN];
Damien Miller62116dc2001-12-24 01:41:47 +1100585 struct passwd *pw;
586
587 pw = getpwuid(getuid());
588 if (pw == NULL)
Damien Miller7b10ef42002-01-21 23:44:12 +1100589 fatal("Couldn't get password entry for current user "
590 "(%i): %s", getuid(), strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100591
592 snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir,
593 SSH_PRNG_SEED_FILE);
594
595 debug("loading PRNG seed from file %.100s", filename);
596
597 if (!prng_check_seedfile(filename)) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100598 verbose("Random seed file not found or invalid, ignoring.");
Damien Miller62116dc2001-12-24 01:41:47 +1100599 return;
600 }
601
602 /* open the file and read in the seed */
603 fd = open(filename, O_RDONLY);
604 if (fd == -1)
Damien Miller7b10ef42002-01-21 23:44:12 +1100605 fatal("could not open PRNG seedfile %.100s (%.100s)",
606 filename, strerror(errno));
Damien Miller62116dc2001-12-24 01:41:47 +1100607
Damien Miller7b10ef42002-01-21 23:44:12 +1100608 if (atomicio(read, fd, &seed, sizeof(seed)) < sizeof(seed)) {
609 verbose("invalid or short read from PRNG seedfile "
610 "%.100s - ignoring", filename);
Damien Miller62116dc2001-12-24 01:41:47 +1100611 memset(seed, '\0', sizeof(seed));
612 }
613 close(fd);
614
615 /* stir in the seed, with estimated entropy zero */
616 RAND_add(&seed, sizeof(seed), 0.0);
617}
618
619
620/*
621 * entropy command initialisation functions
622 */
623int
624prng_read_commands(char *cmdfilename)
625{
Damien Miller7b10ef42002-01-21 23:44:12 +1100626 char cmd[SEED_FILE_SIZE], *cp, line[1024], path[SEED_FILE_SIZE];
Damien Miller62116dc2001-12-24 01:41:47 +1100627 double est;
Damien Miller7b10ef42002-01-21 23:44:12 +1100628 entropy_cmd_t *entcmd;
629 FILE *f;
630 int cur_cmd, linenum, num_cmds, arg;
Damien Miller62116dc2001-12-24 01:41:47 +1100631
Damien Miller7b10ef42002-01-21 23:44:12 +1100632 if ((f = fopen(cmdfilename, "r")) == NULL) {
Damien Miller62116dc2001-12-24 01:41:47 +1100633 fatal("couldn't read entropy commands file %.100s: %.100s",
634 cmdfilename, strerror(errno));
635 }
636
Damien Miller7b10ef42002-01-21 23:44:12 +1100637 num_cmds = 64;
638 entcmd = xmalloc(num_cmds * sizeof(entropy_cmd_t));
639 memset(entcmd, '\0', num_cmds * sizeof(entropy_cmd_t));
Damien Miller62116dc2001-12-24 01:41:47 +1100640
641 /* Read in file */
Damien Miller7b10ef42002-01-21 23:44:12 +1100642 cur_cmd = linenum = 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100643 while (fgets(line, sizeof(line), f)) {
Damien Miller62116dc2001-12-24 01:41:47 +1100644 linenum++;
645
Damien Miller7b10ef42002-01-21 23:44:12 +1100646 /* Skip leading whitespace, blank lines and comments */
Damien Miller62116dc2001-12-24 01:41:47 +1100647 cp = line + strspn(line, WHITESPACE);
648 if ((*cp == 0) || (*cp == '#'))
649 continue; /* done with this line */
650
Damien Miller7b10ef42002-01-21 23:44:12 +1100651 /*
652 * The first non-whitespace char should be a double quote
653 * delimiting the commandline
654 */
Damien Miller62116dc2001-12-24 01:41:47 +1100655 if (*cp != '"') {
Damien Miller7b10ef42002-01-21 23:44:12 +1100656 error("bad entropy command, %.100s line %d",
657 cmdfilename, linenum);
Damien Miller62116dc2001-12-24 01:41:47 +1100658 continue;
659 }
660
Damien Miller7b10ef42002-01-21 23:44:12 +1100661 /*
662 * First token, command args (incl. argv[0]) in double
663 * quotes
664 */
Damien Miller62116dc2001-12-24 01:41:47 +1100665 cp = strtok(cp, "\"");
666 if (cp == NULL) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100667 error("missing or bad command string, %.100s "
668 "line %d -- ignored", cmdfilename, linenum);
Damien Miller62116dc2001-12-24 01:41:47 +1100669 continue;
670 }
671 strlcpy(cmd, cp, sizeof(cmd));
672
Damien Miller7b10ef42002-01-21 23:44:12 +1100673 /* Second token, full command path */
Damien Miller62116dc2001-12-24 01:41:47 +1100674 if ((cp = strtok(NULL, WHITESPACE)) == NULL) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100675 error("missing command path, %.100s "
676 "line %d -- ignored", cmdfilename, linenum);
Damien Miller62116dc2001-12-24 01:41:47 +1100677 continue;
678 }
679
Damien Miller7b10ef42002-01-21 23:44:12 +1100680 /* Did configure mark this as dead? */
Damien Miller62116dc2001-12-24 01:41:47 +1100681 if (strncmp("undef", cp, 5) == 0)
682 continue;
683
684 strlcpy(path, cp, sizeof(path));
685
Damien Miller7b10ef42002-01-21 23:44:12 +1100686 /* Third token, entropy rate estimate for this command */
Damien Miller62116dc2001-12-24 01:41:47 +1100687 if ((cp = strtok(NULL, WHITESPACE)) == NULL) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100688 error("missing entropy estimate, %.100s "
689 "line %d -- ignored", cmdfilename, linenum);
Damien Miller62116dc2001-12-24 01:41:47 +1100690 continue;
691 }
Damien Miller7b10ef42002-01-21 23:44:12 +1100692 est = strtod(cp, NULL);
Damien Miller62116dc2001-12-24 01:41:47 +1100693
694 /* end of line */
695 if ((cp = strtok(NULL, WHITESPACE)) != NULL) {
Damien Miller7b10ef42002-01-21 23:44:12 +1100696 error("garbage at end of line %d in %.100s "
697 "-- ignored", linenum, cmdfilename);
Damien Miller62116dc2001-12-24 01:41:47 +1100698 continue;
699 }
700
701 /* save the command for debug messages */
702 entcmd[cur_cmd].cmdstring = xstrdup(cmd);
703
704 /* split the command args */
705 cp = strtok(cmd, WHITESPACE);
706 arg = 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100707 do {
Damien Miller7b10ef42002-01-21 23:44:12 +1100708 entcmd[cur_cmd].args[arg] = xstrdup(cp);
Damien Miller62116dc2001-12-24 01:41:47 +1100709 arg++;
Damien Miller7b10ef42002-01-21 23:44:12 +1100710 } while(arg < NUM_ARGS && (cp = strtok(NULL, WHITESPACE)));
Damien Miller62116dc2001-12-24 01:41:47 +1100711
712 if (strtok(NULL, WHITESPACE))
Damien Miller7b10ef42002-01-21 23:44:12 +1100713 error("ignored extra commands (max %d), %.100s "
714 "line %d", NUM_ARGS, cmdfilename, linenum);
Damien Miller62116dc2001-12-24 01:41:47 +1100715
716 /* Copy the command path and rate estimate */
717 entcmd[cur_cmd].path = xstrdup(path);
718 entcmd[cur_cmd].rate = est;
719
720 /* Initialise other values */
721 entcmd[cur_cmd].sticky_badness = 1;
722
723 cur_cmd++;
724
Damien Miller7b10ef42002-01-21 23:44:12 +1100725 /*
726 * If we've filled the array, reallocate it twice the size
727 * Do this now because even if this we're on the last
728 * command we need another slot to mark the last entry
729 */
Damien Miller62116dc2001-12-24 01:41:47 +1100730 if (cur_cmd == num_cmds) {
731 num_cmds *= 2;
Damien Miller7b10ef42002-01-21 23:44:12 +1100732 entcmd = xrealloc(entcmd, num_cmds *
733 sizeof(entropy_cmd_t));
Damien Miller62116dc2001-12-24 01:41:47 +1100734 }
735 }
736
737 /* zero the last entry */
Damien Miller7b10ef42002-01-21 23:44:12 +1100738 memset(&entcmd[cur_cmd], '\0', sizeof(entropy_cmd_t));
Damien Miller62116dc2001-12-24 01:41:47 +1100739
740 /* trim to size */
Damien Miller7b10ef42002-01-21 23:44:12 +1100741 entropy_cmds = xrealloc(entcmd, (cur_cmd + 1) *
742 sizeof(entropy_cmd_t));
Damien Miller62116dc2001-12-24 01:41:47 +1100743
Damien Miller7b10ef42002-01-21 23:44:12 +1100744 debug("Loaded %d entropy commands from %.100s", cur_cmd,
745 cmdfilename);
Damien Miller62116dc2001-12-24 01:41:47 +1100746
Damien Miller7b10ef42002-01-21 23:44:12 +1100747 return cur_cmd < MIN_ENTROPY_SOURCES ? -1 : 0;
Damien Miller62116dc2001-12-24 01:41:47 +1100748}
749
Damien Miller62116dc2001-12-24 01:41:47 +1100750int
751main(int argc, char **argv)
752{
Damien Miller7b10ef42002-01-21 23:44:12 +1100753 unsigned char buf[OUTPUT_SEED_SIZE];
Damien Miller62116dc2001-12-24 01:41:47 +1100754 int ret;
755
Kevin Steves94435082001-12-25 04:32:58 +0000756 __progname = get_progname(argv[0]);
Damien Miller62116dc2001-12-24 01:41:47 +1100757 /* XXX: need some debugging mode */
758 log_init(argv[0], SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_USER, 1);
759
Damien Miller7b10ef42002-01-21 23:44:12 +1100760#ifdef USE_SEED_FILES
761 prng_read_seedfile();
762#endif
763
764 /*
765 * Seed the RNG from wherever we can
766 */
767
768 /* Take whatever is on the stack, but don't credit it */
769 RAND_add(buf, sizeof(buf), 0);
770
771 debug("Seeded RNG with %i bytes from system calls",
772 (int)stir_from_system());
773
774#ifdef PRNGD_PORT
Damien Millerc46cc542002-01-22 21:58:27 +1100775 if (get_random_bytes_prngd(buf, sizeof(buf), PRNGD_PORT, NULL) == -1)
Damien Miller7b10ef42002-01-21 23:44:12 +1100776 fatal("Entropy collection failed");
777 RAND_add(buf, sizeof(buf), sizeof(buf));
Damien Millerc46cc542002-01-22 21:58:27 +1100778#elif defined(PRNGD_SOCKET)
779 if (get_random_bytes_prngd(buf, sizeof(buf), 0, PRNGD_SOCKET) == -1)
Damien Miller7b10ef42002-01-21 23:44:12 +1100780 fatal("Entropy collection failed");
781 RAND_add(buf, sizeof(buf), sizeof(buf));
782#else
783 /* Read in collection commands */
784 if (prng_read_commands(SSH_PRNG_COMMAND_FILE) == -1)
785 fatal("PRNG initialisation failed -- exiting.");
786 debug("Seeded RNG with %i bytes from programs",
787 (int)stir_from_programs());
788#endif
789
790#ifdef USE_SEED_FILES
791 prng_write_seedfile();
792#endif
793
794 /*
795 * Write the seed to stdout
796 */
Damien Miller62116dc2001-12-24 01:41:47 +1100797
798 if (!RAND_status())
799 fatal("Not enough entropy in RNG");
800
801 RAND_bytes(buf, sizeof(buf));
802
803 ret = atomicio(write, STDOUT_FILENO, buf, sizeof(buf));
804
805 memset(buf, '\0', sizeof(buf));
806
807 return ret == sizeof(buf) ? 0 : 1;
808}
809