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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>
25d429a2 35#include <string.h>
2e437378 36
37#include <netinet/in.h>
38#include <arpa/inet.h>
39
40#ifdef HAVE_SYS_UN_H
41# include <sys/un.h>
42#endif
43
44#include <errno.h>
45#include <fcntl.h>
46#include <pwd.h>
47#include <signal.h>
48#include <time.h>
49#include <unistd.h>
50
e9a17296 51#include <openssl/rand.h>
52#include <openssl/sha.h>
53#include <openssl/crypto.h>
54
55/* SunOS 4.4.4 needs this */
56#ifdef HAVE_FLOATINGPOINT_H
57# include <floatingpoint.h>
58#endif /* HAVE_FLOATINGPOINT_H */
59
60#include "misc.h"
61#include "xmalloc.h"
62#include "atomicio.h"
63#include "pathnames.h"
64#include "log.h"
65
e9a17296 66/* Number of bytes we write out */
67#define OUTPUT_SEED_SIZE 48
68
69/* Length of on-disk seedfiles */
70#define SEED_FILE_SIZE 1024
71
72/* Maximum number of command-line arguments to read from file */
73#define NUM_ARGS 10
74
75/* Minimum number of usable commands to be considered sufficient */
76#define MIN_ENTROPY_SOURCES 16
77
78/* Path to on-disk seed file (relative to user's home directory */
79#ifndef SSH_PRNG_SEED_FILE
80# define SSH_PRNG_SEED_FILE _PATH_SSH_USER_DIR"/prng_seed"
81#endif
82
ae43c103 83/* Path to PRNG commands list (from pathnames.c) */
84extern char *SSH_PRNG_COMMAND_FILE;
e9a17296 85
e9a17296 86extern char *__progname;
e9a17296 87
88#define WHITESPACE " \t\n"
89
90#ifndef RUSAGE_SELF
91# define RUSAGE_SELF 0
92#endif
93#ifndef RUSAGE_CHILDREN
94# define RUSAGE_CHILDREN 0
95#endif
96
97#if !defined(PRNGD_SOCKET) && !defined(PRNGD_PORT)
98# define USE_SEED_FILES
99#endif
100
101typedef struct {
102 /* Proportion of data that is entropy */
103 double rate;
104 /* Counter goes positive if this command times out */
105 unsigned int badness;
106 /* Increases by factor of two each timeout */
107 unsigned int sticky_badness;
108 /* Path to executable */
109 char *path;
110 /* argv to pass to executable */
111 char *args[NUM_ARGS]; /* XXX: arbitrary limit */
112 /* full command string (debug) */
113 char *cmdstring;
114} entropy_cmd_t;
115
116/* slow command timeouts (all in milliseconds) */
117/* static int entropy_timeout_default = ENTROPY_TIMEOUT_MSEC; */
118static int entropy_timeout_current = ENTROPY_TIMEOUT_MSEC;
119
120/* this is initialised from a file, by prng_read_commands() */
121static entropy_cmd_t *entropy_cmds = NULL;
122
123/* Prototypes */
124double stir_from_system(void);
125double stir_from_programs(void);
126double stir_gettimeofday(double entropy_estimate);
127double stir_clock(double entropy_estimate);
128double stir_rusage(int who, double entropy_estimate);
e54b3d7c 129double hash_command_output(entropy_cmd_t *src, unsigned char *hash);
416fd2a8 130int get_random_bytes_prngd(unsigned char *buf, int len,
e9a17296 131 unsigned short tcp_port, char *socket_path);
132
133/*
134 * Collect 'len' bytes of entropy into 'buf' from PRNGD/EGD daemon
135 * listening either on 'tcp_port', or via Unix domain socket at *
136 * 'socket_path'.
416fd2a8 137 * Either a non-zero tcp_port or a non-null socket_path must be
e9a17296 138 * supplied.
139 * Returns 0 on success, -1 on error
140 */
141int
416fd2a8 142get_random_bytes_prngd(unsigned char *buf, int len,
e9a17296 143 unsigned short tcp_port, char *socket_path)
144{
145 int fd, addr_len, rval, errors;
34fee935 146 u_char msg[2];
e9a17296 147 struct sockaddr_storage addr;
148 struct sockaddr_in *addr_in = (struct sockaddr_in *)&addr;
149 struct sockaddr_un *addr_un = (struct sockaddr_un *)&addr;
150 mysig_t old_sigpipe;
151
152 /* Sanity checks */
153 if (socket_path == NULL && tcp_port == 0)
154 fatal("You must specify a port or a socket");
155 if (socket_path != NULL &&
156 strlen(socket_path) >= sizeof(addr_un->sun_path))
157 fatal("Random pool path is too long");
34fee935 158 if (len <= 0 || len > 255)
159 fatal("Too many bytes (%d) to read from PRNGD", len);
e9a17296 160
161 memset(&addr, '\0', sizeof(addr));
162
163 if (tcp_port != 0) {
164 addr_in->sin_family = AF_INET;
165 addr_in->sin_addr.s_addr = htonl(INADDR_LOOPBACK);
166 addr_in->sin_port = htons(tcp_port);
167 addr_len = sizeof(*addr_in);
168 } else {
169 addr_un->sun_family = AF_UNIX;
170 strlcpy(addr_un->sun_path, socket_path,
171 sizeof(addr_un->sun_path));
172 addr_len = offsetof(struct sockaddr_un, sun_path) +
173 strlen(socket_path) + 1;
174 }
175
176 old_sigpipe = mysignal(SIGPIPE, SIG_IGN);
177
178 errors = 0;
179 rval = -1;
180reopen:
181 fd = socket(addr.ss_family, SOCK_STREAM, 0);
182 if (fd == -1) {
183 error("Couldn't create socket: %s", strerror(errno));
184 goto done;
185 }
186
187 if (connect(fd, (struct sockaddr*)&addr, addr_len) == -1) {
188 if (tcp_port != 0) {
189 error("Couldn't connect to PRNGD port %d: %s",
190 tcp_port, strerror(errno));
191 } else {
192 error("Couldn't connect to PRNGD socket \"%s\": %s",
193 addr_un->sun_path, strerror(errno));
194 }
195 goto done;
196 }
197
198 /* Send blocking read request to PRNGD */
199 msg[0] = 0x02;
200 msg[1] = len;
201
70791e56 202 if (atomicio(vwrite, fd, msg, sizeof(msg)) != sizeof(msg)) {
e9a17296 203 if (errno == EPIPE && errors < 10) {
204 close(fd);
205 errors++;
206 goto reopen;
207 }
208 error("Couldn't write to PRNGD socket: %s",
209 strerror(errno));
210 goto done;
211 }
212
34fee935 213 if (atomicio(read, fd, buf, len) != (size_t)len) {
e9a17296 214 if (errno == EPIPE && errors < 10) {
215 close(fd);
216 errors++;
217 goto reopen;
218 }
219 error("Couldn't read from PRNGD socket: %s",
220 strerror(errno));
221 goto done;
222 }
223
224 rval = 0;
225done:
226 mysignal(SIGPIPE, old_sigpipe);
227 if (fd != -1)
228 close(fd);
229 return rval;
230}
231
34fee935 232static int
233seed_from_prngd(unsigned char *buf, size_t bytes)
234{
235#ifdef PRNGD_PORT
236 debug("trying egd/prngd port %d", PRNGD_PORT);
237 if (get_random_bytes_prngd(buf, bytes, PRNGD_PORT, NULL) == 0)
238 return 0;
239#endif
240#ifdef PRNGD_SOCKET
241 debug("trying egd/prngd socket %s", PRNGD_SOCKET);
242 if (get_random_bytes_prngd(buf, bytes, 0, PRNGD_SOCKET) == 0)
243 return 0;
244#endif
245 return -1;
246}
247
e9a17296 248double
249stir_gettimeofday(double entropy_estimate)
250{
251 struct timeval tv;
252
253 if (gettimeofday(&tv, NULL) == -1)
254 fatal("Couldn't gettimeofday: %s", strerror(errno));
255
256 RAND_add(&tv, sizeof(tv), entropy_estimate);
257
258 return entropy_estimate;
259}
260
261double
262stir_clock(double entropy_estimate)
263{
264#ifdef HAVE_CLOCK
265 clock_t c;
266
267 c = clock();
268 RAND_add(&c, sizeof(c), entropy_estimate);
269
270 return entropy_estimate;
271#else /* _HAVE_CLOCK */
272 return 0;
273#endif /* _HAVE_CLOCK */
274}
275
276double
277stir_rusage(int who, double entropy_estimate)
278{
279#ifdef HAVE_GETRUSAGE
280 struct rusage ru;
281
282 if (getrusage(who, &ru) == -1)
283 return 0;
284
285 RAND_add(&ru, sizeof(ru), entropy_estimate);
286
287 return entropy_estimate;
288#else /* _HAVE_GETRUSAGE */
289 return 0;
290#endif /* _HAVE_GETRUSAGE */
291}
292
293static int
294timeval_diff(struct timeval *t1, struct timeval *t2)
295{
296 int secdiff, usecdiff;
297
298 secdiff = t2->tv_sec - t1->tv_sec;
299 usecdiff = (secdiff*1000000) + (t2->tv_usec - t1->tv_usec);
300 return (int)(usecdiff / 1000);
301}
302
303double
e54b3d7c 304hash_command_output(entropy_cmd_t *src, unsigned char *hash)
e9a17296 305{
306 char buf[8192];
307 fd_set rdset;
308 int bytes_read, cmd_eof, error_abort, msec_elapsed, p[2];
309 int status, total_bytes_read;
310 static int devnull = -1;
311 pid_t pid;
312 SHA_CTX sha;
313 struct timeval tv_start, tv_current;
314
315 debug3("Reading output from \'%s\'", src->cmdstring);
316
317 if (devnull == -1) {
318 devnull = open("/dev/null", O_RDWR);
319 if (devnull == -1)
416fd2a8 320 fatal("Couldn't open /dev/null: %s",
e9a17296 321 strerror(errno));
322 }
323
324 if (pipe(p) == -1)
325 fatal("Couldn't open pipe: %s", strerror(errno));
326
327 (void)gettimeofday(&tv_start, NULL); /* record start time */
328
329 switch (pid = fork()) {
330 case -1: /* Error */
331 close(p[0]);
332 close(p[1]);
333 fatal("Couldn't fork: %s", strerror(errno));
334 /* NOTREACHED */
335 case 0: /* Child */
336 dup2(devnull, STDIN_FILENO);
337 dup2(p[1], STDOUT_FILENO);
338 dup2(p[1], STDERR_FILENO);
339 close(p[0]);
340 close(p[1]);
341 close(devnull);
342
343 execv(src->path, (char**)(src->args));
344
416fd2a8 345 debug("(child) Couldn't exec '%s': %s",
e9a17296 346 src->cmdstring, strerror(errno));
347 _exit(-1);
348 default: /* Parent */
349 break;
350 }
351
352 RAND_add(&pid, sizeof(&pid), 0.0);
353
354 close(p[1]);
355
356 /* Hash output from child */
357 SHA1_Init(&sha);
358
359 cmd_eof = error_abort = msec_elapsed = total_bytes_read = 0;
360 while (!error_abort && !cmd_eof) {
361 int ret;
362 struct timeval tv;
363 int msec_remaining;
364
365 (void) gettimeofday(&tv_current, 0);
366 msec_elapsed = timeval_diff(&tv_start, &tv_current);
367 if (msec_elapsed >= entropy_timeout_current) {
368 error_abort=1;
369 continue;
370 }
371 msec_remaining = entropy_timeout_current - msec_elapsed;
372
373 FD_ZERO(&rdset);
374 FD_SET(p[0], &rdset);
375 tv.tv_sec = msec_remaining / 1000;
376 tv.tv_usec = (msec_remaining % 1000) * 1000;
377
378 ret = select(p[0] + 1, &rdset, NULL, NULL, &tv);
379
380 RAND_add(&tv, sizeof(tv), 0.0);
381
382 switch (ret) {
383 case 0:
384 /* timer expired */
385 error_abort = 1;
1c14df9e 386 kill(pid, SIGINT);
e9a17296 387 break;
388 case 1:
389 /* command input */
390 do {
391 bytes_read = read(p[0], buf, sizeof(buf));
392 } while (bytes_read == -1 && errno == EINTR);
393 RAND_add(&bytes_read, sizeof(&bytes_read), 0.0);
394 if (bytes_read == -1) {
395 error_abort = 1;
396 break;
397 } else if (bytes_read) {
398 SHA1_Update(&sha, buf, bytes_read);
399 total_bytes_read += bytes_read;
400 } else {
401 cmd_eof = 1;
402 }
403 break;
404 case -1:
405 default:
406 /* error */
416fd2a8 407 debug("Command '%s': select() failed: %s",
e9a17296 408 src->cmdstring, strerror(errno));
409 error_abort = 1;
410 break;
411 }
412 }
413
414 SHA1_Final(hash, &sha);
415
416 close(p[0]);
417
418 debug3("Time elapsed: %d msec", msec_elapsed);
419
420 if (waitpid(pid, &status, 0) == -1) {
34fee935 421 error("Couldn't wait for child '%s' completion: %s",
422 src->cmdstring, strerror(errno));
e9a17296 423 return 0.0;
424 }
425
426 RAND_add(&status, sizeof(&status), 0.0);
427
428 if (error_abort) {
429 /*
430 * Closing p[0] on timeout causes the entropy command to
416fd2a8 431 * SIGPIPE. Take whatever output we got, and mark this
432 * command as slow
e9a17296 433 */
434 debug2("Command '%s' timed out", src->cmdstring);
435 src->sticky_badness *= 2;
436 src->badness = src->sticky_badness;
437 return total_bytes_read;
438 }
439
440 if (WIFEXITED(status)) {
441 if (WEXITSTATUS(status) == 0) {
442 return total_bytes_read;
443 } else {
444 debug2("Command '%s' exit status was %d",
445 src->cmdstring, WEXITSTATUS(status));
446 src->badness = src->sticky_badness = 128;
447 return 0.0;
448 }
449 } else if (WIFSIGNALED(status)) {
450 debug2("Command '%s' returned on uncaught signal %d !",
451 src->cmdstring, status);
452 src->badness = src->sticky_badness = 128;
453 return 0.0;
454 } else
455 return 0.0;
456}
457
458double
459stir_from_system(void)
460{
461 double total_entropy_estimate;
462 long int i;
463
464 total_entropy_estimate = 0;
465
466 i = getpid();
467 RAND_add(&i, sizeof(i), 0.5);
468 total_entropy_estimate += 0.1;
469
470 i = getppid();
471 RAND_add(&i, sizeof(i), 0.5);
472 total_entropy_estimate += 0.1;
473
474 i = getuid();
475 RAND_add(&i, sizeof(i), 0.0);
476 i = getgid();
477 RAND_add(&i, sizeof(i), 0.0);
478
479 total_entropy_estimate += stir_gettimeofday(1.0);
480 total_entropy_estimate += stir_clock(0.5);
481 total_entropy_estimate += stir_rusage(RUSAGE_SELF, 2.0);
482
483 return total_entropy_estimate;
484}
485
486double
487stir_from_programs(void)
488{
489 int c;
490 double entropy, total_entropy;
e54b3d7c 491 unsigned char hash[SHA_DIGEST_LENGTH];
e9a17296 492
493 total_entropy = 0;
494 for(c = 0; entropy_cmds[c].path != NULL; c++) {
495 if (!entropy_cmds[c].badness) {
496 /* Hash output from command */
497 entropy = hash_command_output(&entropy_cmds[c],
498 hash);
499
500 /* Scale back estimate by command's rate */
501 entropy *= entropy_cmds[c].rate;
502
503 /* Upper bound of entropy is SHA_DIGEST_LENGTH */
504 if (entropy > SHA_DIGEST_LENGTH)
505 entropy = SHA_DIGEST_LENGTH;
506
507 /* Stir it in */
508 RAND_add(hash, sizeof(hash), entropy);
509
416fd2a8 510 debug3("Got %0.2f bytes of entropy from '%s'",
e9a17296 511 entropy, entropy_cmds[c].cmdstring);
512
513 total_entropy += entropy;
514
515 /* Execution time should be a bit unpredictable */
516 total_entropy += stir_gettimeofday(0.05);
517 total_entropy += stir_clock(0.05);
518 total_entropy += stir_rusage(RUSAGE_SELF, 0.1);
519 total_entropy += stir_rusage(RUSAGE_CHILDREN, 0.1);
520 } else {
521 debug2("Command '%s' disabled (badness %d)",
416fd2a8 522 entropy_cmds[c].cmdstring,
e9a17296 523 entropy_cmds[c].badness);
524
525 if (entropy_cmds[c].badness > 0)
526 entropy_cmds[c].badness--;
527 }
528 }
529
530 return total_entropy;
531}
532
533/*
534 * prng seedfile functions
535 */
536int
537prng_check_seedfile(char *filename)
538{
539 struct stat st;
540
541 /*
416fd2a8 542 * XXX raceable: eg replace seed between this stat and subsequent
543 * open. Not such a problem because we don't really trust the
e9a17296 544 * seed file anyway.
545 * XXX: use secure path checking as elsewhere in OpenSSH
546 */
547 if (lstat(filename, &st) == -1) {
548 /* Give up on hard errors */
549 if (errno != ENOENT)
550 debug("WARNING: Couldn't stat random seed file "
551 "\"%.100s\": %s", filename, strerror(errno));
552 return 0;
553 }
554
555 /* regular file? */
556 if (!S_ISREG(st.st_mode))
557 fatal("PRNG seedfile %.100s is not a regular file",
558 filename);
559
560 /* mode 0600, owned by root or the current user? */
561 if (((st.st_mode & 0177) != 0) || !(st.st_uid == getuid())) {
562 debug("WARNING: PRNG seedfile %.100s must be mode 0600, "
70791e56 563 "owned by uid %li", filename, (long int)getuid());
e9a17296 564 return 0;
565 }
566
567 return 1;
568}
569
570void
571prng_write_seedfile(void)
572{
34fee935 573 int fd, save_errno;
e54b3d7c 574 unsigned char seed[SEED_FILE_SIZE];
34fee935 575 char filename[MAXPATHLEN], tmpseed[MAXPATHLEN];
e9a17296 576 struct passwd *pw;
34fee935 577 mode_t old_umask;
e9a17296 578
579 pw = getpwuid(getuid());
580 if (pw == NULL)
581 fatal("Couldn't get password entry for current user "
70791e56 582 "(%li): %s", (long int)getuid(), strerror(errno));
e9a17296 583
584 /* Try to ensure that the parent directory is there */
585 snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir,
586 _PATH_SSH_USER_DIR);
2e437378 587 if (mkdir(filename, 0700) < 0 && errno != EEXIST)
588 fatal("mkdir %.200s: %s", filename, strerror(errno));
e9a17296 589
590 snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir,
591 SSH_PRNG_SEED_FILE);
592
34fee935 593 strlcpy(tmpseed, filename, sizeof(tmpseed));
594 if (strlcat(tmpseed, ".XXXXXXXXXX", sizeof(tmpseed)) >=
595 sizeof(tmpseed))
596 fatal("PRNG seed filename too long");
e9a17296 597
1c14df9e 598 if (RAND_bytes(seed, sizeof(seed)) <= 0)
416fd2a8 599 fatal("PRNG seed extraction failed");
e9a17296 600
601 /* Don't care if the seed doesn't exist */
602 prng_check_seedfile(filename);
603
34fee935 604 old_umask = umask(0177);
605
606 if ((fd = mkstemp(tmpseed)) == -1) {
607 debug("WARNING: couldn't make temporary PRNG seedfile %.100s "
608 "(%.100s)", tmpseed, strerror(errno));
e9a17296 609 } else {
34fee935 610 debug("writing PRNG seed to file %.100s", tmpseed);
611 if (atomicio(vwrite, fd, &seed, sizeof(seed)) < sizeof(seed)) {
612 save_errno = errno;
613 close(fd);
614 unlink(tmpseed);
e9a17296 615 fatal("problem writing PRNG seedfile %.100s "
34fee935 616 "(%.100s)", filename, strerror(save_errno));
617 }
e9a17296 618 close(fd);
34fee935 619 debug("moving temporary PRNG seed to file %.100s", filename);
620 if (rename(tmpseed, filename) == -1) {
621 save_errno = errno;
622 unlink(tmpseed);
623 fatal("problem renaming PRNG seedfile from %.100s "
624 "to %.100s (%.100s)", tmpseed, filename,
625 strerror(save_errno));
626 }
e9a17296 627 }
34fee935 628 umask(old_umask);
e9a17296 629}
630
631void
632prng_read_seedfile(void)
633{
634 int fd;
635 char seed[SEED_FILE_SIZE], filename[MAXPATHLEN];
636 struct passwd *pw;
637
638 pw = getpwuid(getuid());
639 if (pw == NULL)
640 fatal("Couldn't get password entry for current user "
70791e56 641 "(%li): %s", (long int)getuid(), strerror(errno));
e9a17296 642
643 snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir,
644 SSH_PRNG_SEED_FILE);
645
646 debug("loading PRNG seed from file %.100s", filename);
647
648 if (!prng_check_seedfile(filename)) {
649 verbose("Random seed file not found or invalid, ignoring.");
650 return;
651 }
652
653 /* open the file and read in the seed */
654 fd = open(filename, O_RDONLY);
655 if (fd == -1)
656 fatal("could not open PRNG seedfile %.100s (%.100s)",
657 filename, strerror(errno));
658
659 if (atomicio(read, fd, &seed, sizeof(seed)) < sizeof(seed)) {
660 verbose("invalid or short read from PRNG seedfile "
661 "%.100s - ignoring", filename);
662 memset(seed, '\0', sizeof(seed));
663 }
664 close(fd);
665
666 /* stir in the seed, with estimated entropy zero */
667 RAND_add(&seed, sizeof(seed), 0.0);
668}
669
670
671/*
672 * entropy command initialisation functions
673 */
674int
675prng_read_commands(char *cmdfilename)
676{
677 char cmd[SEED_FILE_SIZE], *cp, line[1024], path[SEED_FILE_SIZE];
678 double est;
679 entropy_cmd_t *entcmd;
680 FILE *f;
681 int cur_cmd, linenum, num_cmds, arg;
682
683 if ((f = fopen(cmdfilename, "r")) == NULL) {
684 fatal("couldn't read entropy commands file %.100s: %.100s",
685 cmdfilename, strerror(errno));
686 }
687
688 num_cmds = 64;
2e437378 689 entcmd = xcalloc(num_cmds, sizeof(entropy_cmd_t));
e9a17296 690
691 /* Read in file */
692 cur_cmd = linenum = 0;
693 while (fgets(line, sizeof(line), f)) {
694 linenum++;
695
696 /* Skip leading whitespace, blank lines and comments */
697 cp = line + strspn(line, WHITESPACE);
698 if ((*cp == 0) || (*cp == '#'))
699 continue; /* done with this line */
700
701 /*
416fd2a8 702 * The first non-whitespace char should be a double quote
e9a17296 703 * delimiting the commandline
704 */
705 if (*cp != '"') {
706 error("bad entropy command, %.100s line %d",
707 cmdfilename, linenum);
708 continue;
709 }
710
711 /*
712 * First token, command args (incl. argv[0]) in double
713 * quotes
714 */
715 cp = strtok(cp, "\"");
716 if (cp == NULL) {
717 error("missing or bad command string, %.100s "
718 "line %d -- ignored", cmdfilename, linenum);
719 continue;
720 }
721 strlcpy(cmd, cp, sizeof(cmd));
722
723 /* Second token, full command path */
724 if ((cp = strtok(NULL, WHITESPACE)) == NULL) {
725 error("missing command path, %.100s "
726 "line %d -- ignored", cmdfilename, linenum);
727 continue;
728 }
729
730 /* Did configure mark this as dead? */
731 if (strncmp("undef", cp, 5) == 0)
732 continue;
733
734 strlcpy(path, cp, sizeof(path));
735
736 /* Third token, entropy rate estimate for this command */
737 if ((cp = strtok(NULL, WHITESPACE)) == NULL) {
738 error("missing entropy estimate, %.100s "
739 "line %d -- ignored", cmdfilename, linenum);
740 continue;
741 }
742 est = strtod(cp, NULL);
743
744 /* end of line */
745 if ((cp = strtok(NULL, WHITESPACE)) != NULL) {
746 error("garbage at end of line %d in %.100s "
747 "-- ignored", linenum, cmdfilename);
748 continue;
749 }
750
751 /* save the command for debug messages */
752 entcmd[cur_cmd].cmdstring = xstrdup(cmd);
753
754 /* split the command args */
755 cp = strtok(cmd, WHITESPACE);
756 arg = 0;
757 do {
758 entcmd[cur_cmd].args[arg] = xstrdup(cp);
759 arg++;
760 } while(arg < NUM_ARGS && (cp = strtok(NULL, WHITESPACE)));
761
762 if (strtok(NULL, WHITESPACE))
763 error("ignored extra commands (max %d), %.100s "
764 "line %d", NUM_ARGS, cmdfilename, linenum);
765
766 /* Copy the command path and rate estimate */
767 entcmd[cur_cmd].path = xstrdup(path);
768 entcmd[cur_cmd].rate = est;
769
770 /* Initialise other values */
771 entcmd[cur_cmd].sticky_badness = 1;
772
773 cur_cmd++;
774
775 /*
776 * If we've filled the array, reallocate it twice the size
416fd2a8 777 * Do this now because even if this we're on the last
e9a17296 778 * command we need another slot to mark the last entry
779 */
780 if (cur_cmd == num_cmds) {
781 num_cmds *= 2;
2e437378 782 entcmd = xrealloc(entcmd, num_cmds,
e9a17296 783 sizeof(entropy_cmd_t));
784 }
785 }
786
787 /* zero the last entry */
788 memset(&entcmd[cur_cmd], '\0', sizeof(entropy_cmd_t));
789
790 /* trim to size */
2e437378 791 entropy_cmds = xrealloc(entcmd, (cur_cmd + 1),
e9a17296 792 sizeof(entropy_cmd_t));
793
794 debug("Loaded %d entropy commands from %.100s", cur_cmd,
795 cmdfilename);
796
2e437378 797 fclose(f);
e9a17296 798 return cur_cmd < MIN_ENTROPY_SOURCES ? -1 : 0;
799}
800
2980ea68 801void
802usage(void)
803{
804 fprintf(stderr, "Usage: %s [options]\n", __progname);
805 fprintf(stderr, " -v Verbose; display verbose debugging messages.\n");
806 fprintf(stderr, " Multiple -v increases verbosity.\n");
34fee935 807 fprintf(stderr, " -x Force output in hexadecimal (for debugging)\n");
2980ea68 808 fprintf(stderr, " -X Force output in binary\n");
809 fprintf(stderr, " -b bytes Number of bytes to output (default %d)\n",
810 OUTPUT_SEED_SIZE);
811}
812
416fd2a8 813int
e9a17296 814main(int argc, char **argv)
815{
2980ea68 816 unsigned char *buf;
817 int ret, ch, debug_level, output_hex, bytes;
818 extern char *optarg;
819 LogLevel ll;
e9a17296 820
70791e56 821 __progname = ssh_get_progname(argv[0]);
ae43c103 822 init_pathnames();
e9a17296 823 log_init(argv[0], SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_USER, 1);
824
2980ea68 825 ll = SYSLOG_LEVEL_INFO;
826 debug_level = output_hex = 0;
827 bytes = OUTPUT_SEED_SIZE;
828
829 /* Don't write binary data to a tty, unless we are forced to */
830 if (isatty(STDOUT_FILENO))
831 output_hex = 1;
416fd2a8 832
2980ea68 833 while ((ch = getopt(argc, argv, "vxXhb:")) != -1) {
834 switch (ch) {
835 case 'v':
836 if (debug_level < 3)
837 ll = SYSLOG_LEVEL_DEBUG1 + debug_level++;
838 break;
839 case 'x':
840 output_hex = 1;
841 break;
842 case 'X':
843 output_hex = 0;
844 break;
845 case 'b':
846 if ((bytes = atoi(optarg)) <= 0)
847 fatal("Invalid number of output bytes");
848 break;
849 case 'h':
850 usage();
851 exit(0);
852 default:
853 error("Invalid commandline option");
854 usage();
855 }
856 }
857
858 log_init(argv[0], ll, SYSLOG_FACILITY_USER, 1);
416fd2a8 859
e9a17296 860#ifdef USE_SEED_FILES
861 prng_read_seedfile();
862#endif
863
2980ea68 864 buf = xmalloc(bytes);
865
e9a17296 866 /*
867 * Seed the RNG from wherever we can
868 */
416fd2a8 869
e9a17296 870 /* Take whatever is on the stack, but don't credit it */
2980ea68 871 RAND_add(buf, bytes, 0);
e9a17296 872
416fd2a8 873 debug("Seeded RNG with %i bytes from system calls",
e9a17296 874 (int)stir_from_system());
875
34fee935 876 /* try prngd, fall back to commands if prngd fails or not configured */
877 if (seed_from_prngd(buf, bytes) == 0) {
878 RAND_add(buf, bytes, bytes);
879 } else {
880 /* Read in collection commands */
881 if (prng_read_commands(SSH_PRNG_COMMAND_FILE) == -1)
882 fatal("PRNG initialisation failed -- exiting.");
883 debug("Seeded RNG with %i bytes from programs",
884 (int)stir_from_programs());
885 }
e9a17296 886
887#ifdef USE_SEED_FILES
888 prng_write_seedfile();
889#endif
890
891 /*
892 * Write the seed to stdout
893 */
894
895 if (!RAND_status())
896 fatal("Not enough entropy in RNG");
897
1c14df9e 898 if (RAND_bytes(buf, bytes) <= 0)
899 fatal("Couldn't extract entropy from PRNG");
e9a17296 900
2980ea68 901 if (output_hex) {
902 for(ret = 0; ret < bytes; ret++)
903 printf("%02x", (unsigned char)(buf[ret]));
904 printf("\n");
905 } else
70791e56 906 ret = atomicio(vwrite, STDOUT_FILENO, buf, bytes);
416fd2a8 907
2980ea68 908 memset(buf, '\0', bytes);
909 xfree(buf);
416fd2a8 910
2980ea68 911 return ret == bytes ? 0 : 1;
e9a17296 912}
34fee935 913
914/*
915 * We may attempt to re-seed during mkstemp if we are using the one in the
916 * compat library (via mkstemp -> _gettemp -> arc4random -> seed_rng) so we
917 * need our own seed_rng(). We must also check that we have enough entropy.
918 */
919void
920seed_rng(void)
921{
922 if (!RAND_status())
923 fatal("Not enough entropy in RNG");
924}
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