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[gssapi-openssh.git] / openssh / ssh-rand-helper.c
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e9a17296 1/*
2 * Copyright (c) 2001-2002 Damien Miller. All rights reserved.
3 *
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
2e437378 27#include <sys/types.h>
28#include <sys/resource.h>
29#include <sys/stat.h>
30#include <sys/wait.h>
31#include <sys/socket.h>
32
33#include <stdarg.h>
34#include <stddef.h>
35
36#include <netinet/in.h>
37#include <arpa/inet.h>
38
39#ifdef HAVE_SYS_UN_H
40# include <sys/un.h>
41#endif
42
43#include <errno.h>
44#include <fcntl.h>
45#include <pwd.h>
46#include <signal.h>
47#include <time.h>
48#include <unistd.h>
49
e9a17296 50#include <openssl/rand.h>
51#include <openssl/sha.h>
52#include <openssl/crypto.h>
53
54/* SunOS 4.4.4 needs this */
55#ifdef HAVE_FLOATINGPOINT_H
56# include <floatingpoint.h>
57#endif /* HAVE_FLOATINGPOINT_H */
58
59#include "misc.h"
60#include "xmalloc.h"
61#include "atomicio.h"
62#include "pathnames.h"
63#include "log.h"
64
e9a17296 65/* Number of bytes we write out */
66#define OUTPUT_SEED_SIZE 48
67
68/* Length of on-disk seedfiles */
69#define SEED_FILE_SIZE 1024
70
71/* Maximum number of command-line arguments to read from file */
72#define NUM_ARGS 10
73
74/* Minimum number of usable commands to be considered sufficient */
75#define MIN_ENTROPY_SOURCES 16
76
77/* Path to on-disk seed file (relative to user's home directory */
78#ifndef SSH_PRNG_SEED_FILE
79# define SSH_PRNG_SEED_FILE _PATH_SSH_USER_DIR"/prng_seed"
80#endif
81
ae43c103 82/* Path to PRNG commands list (from pathnames.c) */
83extern char *SSH_PRNG_COMMAND_FILE;
e9a17296 84
e9a17296 85extern char *__progname;
e9a17296 86
87#define WHITESPACE " \t\n"
88
89#ifndef RUSAGE_SELF
90# define RUSAGE_SELF 0
91#endif
92#ifndef RUSAGE_CHILDREN
93# define RUSAGE_CHILDREN 0
94#endif
95
96#if !defined(PRNGD_SOCKET) && !defined(PRNGD_PORT)
97# define USE_SEED_FILES
98#endif
99
100typedef struct {
101 /* Proportion of data that is entropy */
102 double rate;
103 /* Counter goes positive if this command times out */
104 unsigned int badness;
105 /* Increases by factor of two each timeout */
106 unsigned int sticky_badness;
107 /* Path to executable */
108 char *path;
109 /* argv to pass to executable */
110 char *args[NUM_ARGS]; /* XXX: arbitrary limit */
111 /* full command string (debug) */
112 char *cmdstring;
113} entropy_cmd_t;
114
115/* slow command timeouts (all in milliseconds) */
116/* static int entropy_timeout_default = ENTROPY_TIMEOUT_MSEC; */
117static int entropy_timeout_current = ENTROPY_TIMEOUT_MSEC;
118
119/* this is initialised from a file, by prng_read_commands() */
120static entropy_cmd_t *entropy_cmds = NULL;
121
122/* Prototypes */
123double stir_from_system(void);
124double stir_from_programs(void);
125double stir_gettimeofday(double entropy_estimate);
126double stir_clock(double entropy_estimate);
127double stir_rusage(int who, double entropy_estimate);
e54b3d7c 128double hash_command_output(entropy_cmd_t *src, unsigned char *hash);
416fd2a8 129int get_random_bytes_prngd(unsigned char *buf, int len,
e9a17296 130 unsigned short tcp_port, char *socket_path);
131
132/*
133 * Collect 'len' bytes of entropy into 'buf' from PRNGD/EGD daemon
134 * listening either on 'tcp_port', or via Unix domain socket at *
135 * 'socket_path'.
416fd2a8 136 * Either a non-zero tcp_port or a non-null socket_path must be
e9a17296 137 * supplied.
138 * Returns 0 on success, -1 on error
139 */
140int
416fd2a8 141get_random_bytes_prngd(unsigned char *buf, int len,
e9a17296 142 unsigned short tcp_port, char *socket_path)
143{
144 int fd, addr_len, rval, errors;
34fee935 145 u_char msg[2];
e9a17296 146 struct sockaddr_storage addr;
147 struct sockaddr_in *addr_in = (struct sockaddr_in *)&addr;
148 struct sockaddr_un *addr_un = (struct sockaddr_un *)&addr;
149 mysig_t old_sigpipe;
150
151 /* Sanity checks */
152 if (socket_path == NULL && tcp_port == 0)
153 fatal("You must specify a port or a socket");
154 if (socket_path != NULL &&
155 strlen(socket_path) >= sizeof(addr_un->sun_path))
156 fatal("Random pool path is too long");
34fee935 157 if (len <= 0 || len > 255)
158 fatal("Too many bytes (%d) to read from PRNGD", len);
e9a17296 159
160 memset(&addr, '\0', sizeof(addr));
161
162 if (tcp_port != 0) {
163 addr_in->sin_family = AF_INET;
164 addr_in->sin_addr.s_addr = htonl(INADDR_LOOPBACK);
165 addr_in->sin_port = htons(tcp_port);
166 addr_len = sizeof(*addr_in);
167 } else {
168 addr_un->sun_family = AF_UNIX;
169 strlcpy(addr_un->sun_path, socket_path,
170 sizeof(addr_un->sun_path));
171 addr_len = offsetof(struct sockaddr_un, sun_path) +
172 strlen(socket_path) + 1;
173 }
174
175 old_sigpipe = mysignal(SIGPIPE, SIG_IGN);
176
177 errors = 0;
178 rval = -1;
179reopen:
180 fd = socket(addr.ss_family, SOCK_STREAM, 0);
181 if (fd == -1) {
182 error("Couldn't create socket: %s", strerror(errno));
183 goto done;
184 }
185
186 if (connect(fd, (struct sockaddr*)&addr, addr_len) == -1) {
187 if (tcp_port != 0) {
188 error("Couldn't connect to PRNGD port %d: %s",
189 tcp_port, strerror(errno));
190 } else {
191 error("Couldn't connect to PRNGD socket \"%s\": %s",
192 addr_un->sun_path, strerror(errno));
193 }
194 goto done;
195 }
196
197 /* Send blocking read request to PRNGD */
198 msg[0] = 0x02;
199 msg[1] = len;
200
70791e56 201 if (atomicio(vwrite, fd, msg, sizeof(msg)) != sizeof(msg)) {
e9a17296 202 if (errno == EPIPE && errors < 10) {
203 close(fd);
204 errors++;
205 goto reopen;
206 }
207 error("Couldn't write to PRNGD socket: %s",
208 strerror(errno));
209 goto done;
210 }
211
34fee935 212 if (atomicio(read, fd, buf, len) != (size_t)len) {
e9a17296 213 if (errno == EPIPE && errors < 10) {
214 close(fd);
215 errors++;
216 goto reopen;
217 }
218 error("Couldn't read from PRNGD socket: %s",
219 strerror(errno));
220 goto done;
221 }
222
223 rval = 0;
224done:
225 mysignal(SIGPIPE, old_sigpipe);
226 if (fd != -1)
227 close(fd);
228 return rval;
229}
230
34fee935 231static int
232seed_from_prngd(unsigned char *buf, size_t bytes)
233{
234#ifdef PRNGD_PORT
235 debug("trying egd/prngd port %d", PRNGD_PORT);
236 if (get_random_bytes_prngd(buf, bytes, PRNGD_PORT, NULL) == 0)
237 return 0;
238#endif
239#ifdef PRNGD_SOCKET
240 debug("trying egd/prngd socket %s", PRNGD_SOCKET);
241 if (get_random_bytes_prngd(buf, bytes, 0, PRNGD_SOCKET) == 0)
242 return 0;
243#endif
244 return -1;
245}
246
e9a17296 247double
248stir_gettimeofday(double entropy_estimate)
249{
250 struct timeval tv;
251
252 if (gettimeofday(&tv, NULL) == -1)
253 fatal("Couldn't gettimeofday: %s", strerror(errno));
254
255 RAND_add(&tv, sizeof(tv), entropy_estimate);
256
257 return entropy_estimate;
258}
259
260double
261stir_clock(double entropy_estimate)
262{
263#ifdef HAVE_CLOCK
264 clock_t c;
265
266 c = clock();
267 RAND_add(&c, sizeof(c), entropy_estimate);
268
269 return entropy_estimate;
270#else /* _HAVE_CLOCK */
271 return 0;
272#endif /* _HAVE_CLOCK */
273}
274
275double
276stir_rusage(int who, double entropy_estimate)
277{
278#ifdef HAVE_GETRUSAGE
279 struct rusage ru;
280
281 if (getrusage(who, &ru) == -1)
282 return 0;
283
284 RAND_add(&ru, sizeof(ru), entropy_estimate);
285
286 return entropy_estimate;
287#else /* _HAVE_GETRUSAGE */
288 return 0;
289#endif /* _HAVE_GETRUSAGE */
290}
291
292static int
293timeval_diff(struct timeval *t1, struct timeval *t2)
294{
295 int secdiff, usecdiff;
296
297 secdiff = t2->tv_sec - t1->tv_sec;
298 usecdiff = (secdiff*1000000) + (t2->tv_usec - t1->tv_usec);
299 return (int)(usecdiff / 1000);
300}
301
302double
e54b3d7c 303hash_command_output(entropy_cmd_t *src, unsigned char *hash)
e9a17296 304{
305 char buf[8192];
306 fd_set rdset;
307 int bytes_read, cmd_eof, error_abort, msec_elapsed, p[2];
308 int status, total_bytes_read;
309 static int devnull = -1;
310 pid_t pid;
311 SHA_CTX sha;
312 struct timeval tv_start, tv_current;
313
314 debug3("Reading output from \'%s\'", src->cmdstring);
315
316 if (devnull == -1) {
317 devnull = open("/dev/null", O_RDWR);
318 if (devnull == -1)
416fd2a8 319 fatal("Couldn't open /dev/null: %s",
e9a17296 320 strerror(errno));
321 }
322
323 if (pipe(p) == -1)
324 fatal("Couldn't open pipe: %s", strerror(errno));
325
326 (void)gettimeofday(&tv_start, NULL); /* record start time */
327
328 switch (pid = fork()) {
329 case -1: /* Error */
330 close(p[0]);
331 close(p[1]);
332 fatal("Couldn't fork: %s", strerror(errno));
333 /* NOTREACHED */
334 case 0: /* Child */
335 dup2(devnull, STDIN_FILENO);
336 dup2(p[1], STDOUT_FILENO);
337 dup2(p[1], STDERR_FILENO);
338 close(p[0]);
339 close(p[1]);
340 close(devnull);
341
342 execv(src->path, (char**)(src->args));
343
416fd2a8 344 debug("(child) Couldn't exec '%s': %s",
e9a17296 345 src->cmdstring, strerror(errno));
346 _exit(-1);
347 default: /* Parent */
348 break;
349 }
350
351 RAND_add(&pid, sizeof(&pid), 0.0);
352
353 close(p[1]);
354
355 /* Hash output from child */
356 SHA1_Init(&sha);
357
358 cmd_eof = error_abort = msec_elapsed = total_bytes_read = 0;
359 while (!error_abort && !cmd_eof) {
360 int ret;
361 struct timeval tv;
362 int msec_remaining;
363
364 (void) gettimeofday(&tv_current, 0);
365 msec_elapsed = timeval_diff(&tv_start, &tv_current);
366 if (msec_elapsed >= entropy_timeout_current) {
367 error_abort=1;
368 continue;
369 }
370 msec_remaining = entropy_timeout_current - msec_elapsed;
371
372 FD_ZERO(&rdset);
373 FD_SET(p[0], &rdset);
374 tv.tv_sec = msec_remaining / 1000;
375 tv.tv_usec = (msec_remaining % 1000) * 1000;
376
377 ret = select(p[0] + 1, &rdset, NULL, NULL, &tv);
378
379 RAND_add(&tv, sizeof(tv), 0.0);
380
381 switch (ret) {
382 case 0:
383 /* timer expired */
384 error_abort = 1;
1c14df9e 385 kill(pid, SIGINT);
e9a17296 386 break;
387 case 1:
388 /* command input */
389 do {
390 bytes_read = read(p[0], buf, sizeof(buf));
391 } while (bytes_read == -1 && errno == EINTR);
392 RAND_add(&bytes_read, sizeof(&bytes_read), 0.0);
393 if (bytes_read == -1) {
394 error_abort = 1;
395 break;
396 } else if (bytes_read) {
397 SHA1_Update(&sha, buf, bytes_read);
398 total_bytes_read += bytes_read;
399 } else {
400 cmd_eof = 1;
401 }
402 break;
403 case -1:
404 default:
405 /* error */
416fd2a8 406 debug("Command '%s': select() failed: %s",
e9a17296 407 src->cmdstring, strerror(errno));
408 error_abort = 1;
409 break;
410 }
411 }
412
413 SHA1_Final(hash, &sha);
414
415 close(p[0]);
416
417 debug3("Time elapsed: %d msec", msec_elapsed);
418
419 if (waitpid(pid, &status, 0) == -1) {
34fee935 420 error("Couldn't wait for child '%s' completion: %s",
421 src->cmdstring, strerror(errno));
e9a17296 422 return 0.0;
423 }
424
425 RAND_add(&status, sizeof(&status), 0.0);
426
427 if (error_abort) {
428 /*
429 * Closing p[0] on timeout causes the entropy command to
416fd2a8 430 * SIGPIPE. Take whatever output we got, and mark this
431 * command as slow
e9a17296 432 */
433 debug2("Command '%s' timed out", src->cmdstring);
434 src->sticky_badness *= 2;
435 src->badness = src->sticky_badness;
436 return total_bytes_read;
437 }
438
439 if (WIFEXITED(status)) {
440 if (WEXITSTATUS(status) == 0) {
441 return total_bytes_read;
442 } else {
443 debug2("Command '%s' exit status was %d",
444 src->cmdstring, WEXITSTATUS(status));
445 src->badness = src->sticky_badness = 128;
446 return 0.0;
447 }
448 } else if (WIFSIGNALED(status)) {
449 debug2("Command '%s' returned on uncaught signal %d !",
450 src->cmdstring, status);
451 src->badness = src->sticky_badness = 128;
452 return 0.0;
453 } else
454 return 0.0;
455}
456
457double
458stir_from_system(void)
459{
460 double total_entropy_estimate;
461 long int i;
462
463 total_entropy_estimate = 0;
464
465 i = getpid();
466 RAND_add(&i, sizeof(i), 0.5);
467 total_entropy_estimate += 0.1;
468
469 i = getppid();
470 RAND_add(&i, sizeof(i), 0.5);
471 total_entropy_estimate += 0.1;
472
473 i = getuid();
474 RAND_add(&i, sizeof(i), 0.0);
475 i = getgid();
476 RAND_add(&i, sizeof(i), 0.0);
477
478 total_entropy_estimate += stir_gettimeofday(1.0);
479 total_entropy_estimate += stir_clock(0.5);
480 total_entropy_estimate += stir_rusage(RUSAGE_SELF, 2.0);
481
482 return total_entropy_estimate;
483}
484
485double
486stir_from_programs(void)
487{
488 int c;
489 double entropy, total_entropy;
e54b3d7c 490 unsigned char hash[SHA_DIGEST_LENGTH];
e9a17296 491
492 total_entropy = 0;
493 for(c = 0; entropy_cmds[c].path != NULL; c++) {
494 if (!entropy_cmds[c].badness) {
495 /* Hash output from command */
496 entropy = hash_command_output(&entropy_cmds[c],
497 hash);
498
499 /* Scale back estimate by command's rate */
500 entropy *= entropy_cmds[c].rate;
501
502 /* Upper bound of entropy is SHA_DIGEST_LENGTH */
503 if (entropy > SHA_DIGEST_LENGTH)
504 entropy = SHA_DIGEST_LENGTH;
505
506 /* Stir it in */
507 RAND_add(hash, sizeof(hash), entropy);
508
416fd2a8 509 debug3("Got %0.2f bytes of entropy from '%s'",
e9a17296 510 entropy, entropy_cmds[c].cmdstring);
511
512 total_entropy += entropy;
513
514 /* Execution time should be a bit unpredictable */
515 total_entropy += stir_gettimeofday(0.05);
516 total_entropy += stir_clock(0.05);
517 total_entropy += stir_rusage(RUSAGE_SELF, 0.1);
518 total_entropy += stir_rusage(RUSAGE_CHILDREN, 0.1);
519 } else {
520 debug2("Command '%s' disabled (badness %d)",
416fd2a8 521 entropy_cmds[c].cmdstring,
e9a17296 522 entropy_cmds[c].badness);
523
524 if (entropy_cmds[c].badness > 0)
525 entropy_cmds[c].badness--;
526 }
527 }
528
529 return total_entropy;
530}
531
532/*
533 * prng seedfile functions
534 */
535int
536prng_check_seedfile(char *filename)
537{
538 struct stat st;
539
540 /*
416fd2a8 541 * XXX raceable: eg replace seed between this stat and subsequent
542 * open. Not such a problem because we don't really trust the
e9a17296 543 * seed file anyway.
544 * XXX: use secure path checking as elsewhere in OpenSSH
545 */
546 if (lstat(filename, &st) == -1) {
547 /* Give up on hard errors */
548 if (errno != ENOENT)
549 debug("WARNING: Couldn't stat random seed file "
550 "\"%.100s\": %s", filename, strerror(errno));
551 return 0;
552 }
553
554 /* regular file? */
555 if (!S_ISREG(st.st_mode))
556 fatal("PRNG seedfile %.100s is not a regular file",
557 filename);
558
559 /* mode 0600, owned by root or the current user? */
560 if (((st.st_mode & 0177) != 0) || !(st.st_uid == getuid())) {
561 debug("WARNING: PRNG seedfile %.100s must be mode 0600, "
70791e56 562 "owned by uid %li", filename, (long int)getuid());
e9a17296 563 return 0;
564 }
565
566 return 1;
567}
568
569void
570prng_write_seedfile(void)
571{
34fee935 572 int fd, save_errno;
e54b3d7c 573 unsigned char seed[SEED_FILE_SIZE];
34fee935 574 char filename[MAXPATHLEN], tmpseed[MAXPATHLEN];
e9a17296 575 struct passwd *pw;
34fee935 576 mode_t old_umask;
e9a17296 577
578 pw = getpwuid(getuid());
579 if (pw == NULL)
580 fatal("Couldn't get password entry for current user "
70791e56 581 "(%li): %s", (long int)getuid(), strerror(errno));
e9a17296 582
583 /* Try to ensure that the parent directory is there */
584 snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir,
585 _PATH_SSH_USER_DIR);
2e437378 586 if (mkdir(filename, 0700) < 0 && errno != EEXIST)
587 fatal("mkdir %.200s: %s", filename, strerror(errno));
e9a17296 588
589 snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir,
590 SSH_PRNG_SEED_FILE);
591
34fee935 592 strlcpy(tmpseed, filename, sizeof(tmpseed));
593 if (strlcat(tmpseed, ".XXXXXXXXXX", sizeof(tmpseed)) >=
594 sizeof(tmpseed))
595 fatal("PRNG seed filename too long");
e9a17296 596
1c14df9e 597 if (RAND_bytes(seed, sizeof(seed)) <= 0)
416fd2a8 598 fatal("PRNG seed extraction failed");
e9a17296 599
600 /* Don't care if the seed doesn't exist */
601 prng_check_seedfile(filename);
602
34fee935 603 old_umask = umask(0177);
604
605 if ((fd = mkstemp(tmpseed)) == -1) {
606 debug("WARNING: couldn't make temporary PRNG seedfile %.100s "
607 "(%.100s)", tmpseed, strerror(errno));
e9a17296 608 } else {
34fee935 609 debug("writing PRNG seed to file %.100s", tmpseed);
610 if (atomicio(vwrite, fd, &seed, sizeof(seed)) < sizeof(seed)) {
611 save_errno = errno;
612 close(fd);
613 unlink(tmpseed);
e9a17296 614 fatal("problem writing PRNG seedfile %.100s "
34fee935 615 "(%.100s)", filename, strerror(save_errno));
616 }
e9a17296 617 close(fd);
34fee935 618 debug("moving temporary PRNG seed to file %.100s", filename);
619 if (rename(tmpseed, filename) == -1) {
620 save_errno = errno;
621 unlink(tmpseed);
622 fatal("problem renaming PRNG seedfile from %.100s "
623 "to %.100s (%.100s)", tmpseed, filename,
624 strerror(save_errno));
625 }
e9a17296 626 }
34fee935 627 umask(old_umask);
e9a17296 628}
629
630void
631prng_read_seedfile(void)
632{
633 int fd;
634 char seed[SEED_FILE_SIZE], filename[MAXPATHLEN];
635 struct passwd *pw;
636
637 pw = getpwuid(getuid());
638 if (pw == NULL)
639 fatal("Couldn't get password entry for current user "
70791e56 640 "(%li): %s", (long int)getuid(), strerror(errno));
e9a17296 641
642 snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir,
643 SSH_PRNG_SEED_FILE);
644
645 debug("loading PRNG seed from file %.100s", filename);
646
647 if (!prng_check_seedfile(filename)) {
648 verbose("Random seed file not found or invalid, ignoring.");
649 return;
650 }
651
652 /* open the file and read in the seed */
653 fd = open(filename, O_RDONLY);
654 if (fd == -1)
655 fatal("could not open PRNG seedfile %.100s (%.100s)",
656 filename, strerror(errno));
657
658 if (atomicio(read, fd, &seed, sizeof(seed)) < sizeof(seed)) {
659 verbose("invalid or short read from PRNG seedfile "
660 "%.100s - ignoring", filename);
661 memset(seed, '\0', sizeof(seed));
662 }
663 close(fd);
664
665 /* stir in the seed, with estimated entropy zero */
666 RAND_add(&seed, sizeof(seed), 0.0);
667}
668
669
670/*
671 * entropy command initialisation functions
672 */
673int
674prng_read_commands(char *cmdfilename)
675{
676 char cmd[SEED_FILE_SIZE], *cp, line[1024], path[SEED_FILE_SIZE];
677 double est;
678 entropy_cmd_t *entcmd;
679 FILE *f;
680 int cur_cmd, linenum, num_cmds, arg;
681
682 if ((f = fopen(cmdfilename, "r")) == NULL) {
683 fatal("couldn't read entropy commands file %.100s: %.100s",
684 cmdfilename, strerror(errno));
685 }
686
687 num_cmds = 64;
2e437378 688 entcmd = xcalloc(num_cmds, sizeof(entropy_cmd_t));
e9a17296 689
690 /* Read in file */
691 cur_cmd = linenum = 0;
692 while (fgets(line, sizeof(line), f)) {
693 linenum++;
694
695 /* Skip leading whitespace, blank lines and comments */
696 cp = line + strspn(line, WHITESPACE);
697 if ((*cp == 0) || (*cp == '#'))
698 continue; /* done with this line */
699
700 /*
416fd2a8 701 * The first non-whitespace char should be a double quote
e9a17296 702 * delimiting the commandline
703 */
704 if (*cp != '"') {
705 error("bad entropy command, %.100s line %d",
706 cmdfilename, linenum);
707 continue;
708 }
709
710 /*
711 * First token, command args (incl. argv[0]) in double
712 * quotes
713 */
714 cp = strtok(cp, "\"");
715 if (cp == NULL) {
716 error("missing or bad command string, %.100s "
717 "line %d -- ignored", cmdfilename, linenum);
718 continue;
719 }
720 strlcpy(cmd, cp, sizeof(cmd));
721
722 /* Second token, full command path */
723 if ((cp = strtok(NULL, WHITESPACE)) == NULL) {
724 error("missing command path, %.100s "
725 "line %d -- ignored", cmdfilename, linenum);
726 continue;
727 }
728
729 /* Did configure mark this as dead? */
730 if (strncmp("undef", cp, 5) == 0)
731 continue;
732
733 strlcpy(path, cp, sizeof(path));
734
735 /* Third token, entropy rate estimate for this command */
736 if ((cp = strtok(NULL, WHITESPACE)) == NULL) {
737 error("missing entropy estimate, %.100s "
738 "line %d -- ignored", cmdfilename, linenum);
739 continue;
740 }
741 est = strtod(cp, NULL);
742
743 /* end of line */
744 if ((cp = strtok(NULL, WHITESPACE)) != NULL) {
745 error("garbage at end of line %d in %.100s "
746 "-- ignored", linenum, cmdfilename);
747 continue;
748 }
749
750 /* save the command for debug messages */
751 entcmd[cur_cmd].cmdstring = xstrdup(cmd);
752
753 /* split the command args */
754 cp = strtok(cmd, WHITESPACE);
755 arg = 0;
756 do {
757 entcmd[cur_cmd].args[arg] = xstrdup(cp);
758 arg++;
759 } while(arg < NUM_ARGS && (cp = strtok(NULL, WHITESPACE)));
760
761 if (strtok(NULL, WHITESPACE))
762 error("ignored extra commands (max %d), %.100s "
763 "line %d", NUM_ARGS, cmdfilename, linenum);
764
765 /* Copy the command path and rate estimate */
766 entcmd[cur_cmd].path = xstrdup(path);
767 entcmd[cur_cmd].rate = est;
768
769 /* Initialise other values */
770 entcmd[cur_cmd].sticky_badness = 1;
771
772 cur_cmd++;
773
774 /*
775 * If we've filled the array, reallocate it twice the size
416fd2a8 776 * Do this now because even if this we're on the last
e9a17296 777 * command we need another slot to mark the last entry
778 */
779 if (cur_cmd == num_cmds) {
780 num_cmds *= 2;
2e437378 781 entcmd = xrealloc(entcmd, num_cmds,
e9a17296 782 sizeof(entropy_cmd_t));
783 }
784 }
785
786 /* zero the last entry */
787 memset(&entcmd[cur_cmd], '\0', sizeof(entropy_cmd_t));
788
789 /* trim to size */
2e437378 790 entropy_cmds = xrealloc(entcmd, (cur_cmd + 1),
e9a17296 791 sizeof(entropy_cmd_t));
792
793 debug("Loaded %d entropy commands from %.100s", cur_cmd,
794 cmdfilename);
795
2e437378 796 fclose(f);
e9a17296 797 return cur_cmd < MIN_ENTROPY_SOURCES ? -1 : 0;
798}
799
2980ea68 800void
801usage(void)
802{
803 fprintf(stderr, "Usage: %s [options]\n", __progname);
804 fprintf(stderr, " -v Verbose; display verbose debugging messages.\n");
805 fprintf(stderr, " Multiple -v increases verbosity.\n");
34fee935 806 fprintf(stderr, " -x Force output in hexadecimal (for debugging)\n");
2980ea68 807 fprintf(stderr, " -X Force output in binary\n");
808 fprintf(stderr, " -b bytes Number of bytes to output (default %d)\n",
809 OUTPUT_SEED_SIZE);
810}
811
416fd2a8 812int
e9a17296 813main(int argc, char **argv)
814{
2980ea68 815 unsigned char *buf;
816 int ret, ch, debug_level, output_hex, bytes;
817 extern char *optarg;
818 LogLevel ll;
e9a17296 819
70791e56 820 __progname = ssh_get_progname(argv[0]);
ae43c103 821 init_pathnames();
e9a17296 822 log_init(argv[0], SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_USER, 1);
823
2980ea68 824 ll = SYSLOG_LEVEL_INFO;
825 debug_level = output_hex = 0;
826 bytes = OUTPUT_SEED_SIZE;
827
828 /* Don't write binary data to a tty, unless we are forced to */
829 if (isatty(STDOUT_FILENO))
830 output_hex = 1;
416fd2a8 831
2980ea68 832 while ((ch = getopt(argc, argv, "vxXhb:")) != -1) {
833 switch (ch) {
834 case 'v':
835 if (debug_level < 3)
836 ll = SYSLOG_LEVEL_DEBUG1 + debug_level++;
837 break;
838 case 'x':
839 output_hex = 1;
840 break;
841 case 'X':
842 output_hex = 0;
843 break;
844 case 'b':
845 if ((bytes = atoi(optarg)) <= 0)
846 fatal("Invalid number of output bytes");
847 break;
848 case 'h':
849 usage();
850 exit(0);
851 default:
852 error("Invalid commandline option");
853 usage();
854 }
855 }
856
857 log_init(argv[0], ll, SYSLOG_FACILITY_USER, 1);
416fd2a8 858
e9a17296 859#ifdef USE_SEED_FILES
860 prng_read_seedfile();
861#endif
862
2980ea68 863 buf = xmalloc(bytes);
864
e9a17296 865 /*
866 * Seed the RNG from wherever we can
867 */
416fd2a8 868
e9a17296 869 /* Take whatever is on the stack, but don't credit it */
2980ea68 870 RAND_add(buf, bytes, 0);
e9a17296 871
416fd2a8 872 debug("Seeded RNG with %i bytes from system calls",
e9a17296 873 (int)stir_from_system());
874
34fee935 875 /* try prngd, fall back to commands if prngd fails or not configured */
876 if (seed_from_prngd(buf, bytes) == 0) {
877 RAND_add(buf, bytes, bytes);
878 } else {
879 /* Read in collection commands */
880 if (prng_read_commands(SSH_PRNG_COMMAND_FILE) == -1)
881 fatal("PRNG initialisation failed -- exiting.");
882 debug("Seeded RNG with %i bytes from programs",
883 (int)stir_from_programs());
884 }
e9a17296 885
886#ifdef USE_SEED_FILES
887 prng_write_seedfile();
888#endif
889
890 /*
891 * Write the seed to stdout
892 */
893
894 if (!RAND_status())
895 fatal("Not enough entropy in RNG");
896
1c14df9e 897 if (RAND_bytes(buf, bytes) <= 0)
898 fatal("Couldn't extract entropy from PRNG");
e9a17296 899
2980ea68 900 if (output_hex) {
901 for(ret = 0; ret < bytes; ret++)
902 printf("%02x", (unsigned char)(buf[ret]));
903 printf("\n");
904 } else
70791e56 905 ret = atomicio(vwrite, STDOUT_FILENO, buf, bytes);
416fd2a8 906
2980ea68 907 memset(buf, '\0', bytes);
908 xfree(buf);
416fd2a8 909
2980ea68 910 return ret == bytes ? 0 : 1;
e9a17296 911}
34fee935 912
913/*
914 * We may attempt to re-seed during mkstemp if we are using the one in the
915 * compat library (via mkstemp -> _gettemp -> arc4random -> seed_rng) so we
916 * need our own seed_rng(). We must also check that we have enough entropy.
917 */
918void
919seed_rng(void)
920{
921 if (!RAND_status())
922 fatal("Not enough entropy in RNG");
923}
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