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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 | ||
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 | ||
42 | RCSID("$Id$"); | |
43 | ||
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 | |
63 | # define SSH_PRNG_COMMAND_FILE SSHDIR "/ssh_prng_cmds" | |
64 | #endif | |
65 | ||
66 | ||
67 | #ifdef HAVE___PROGNAME | |
68 | extern char *__progname; | |
69 | #else | |
70 | char *__progname; | |
71 | #endif | |
72 | ||
73 | #ifndef offsetof | |
74 | # define offsetof(type, member) ((size_t) &((type *)0)->member) | |
75 | #endif | |
76 | ||
77 | #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 | ||
86 | #if !defined(PRNGD_SOCKET) && !defined(PRNGD_PORT) | |
87 | # define USE_SEED_FILES | |
88 | #endif | |
89 | ||
90 | typedef 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; */ | |
107 | static int entropy_timeout_current = ENTROPY_TIMEOUT_MSEC; | |
108 | ||
109 | /* this is initialised from a file, by prng_read_commands() */ | |
110 | static entropy_cmd_t *entropy_cmds = NULL; | |
111 | ||
112 | /* Prototypes */ | |
113 | double stir_from_system(void); | |
114 | double stir_from_programs(void); | |
115 | double stir_gettimeofday(double entropy_estimate); | |
116 | double stir_clock(double entropy_estimate); | |
117 | double stir_rusage(int who, double entropy_estimate); | |
118 | double hash_command_output(entropy_cmd_t *src, char *hash); | |
119 | int 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 | */ | |
130 | int | |
131 | get_random_bytes_prngd(unsigned char *buf, int len, | |
132 | unsigned short tcp_port, char *socket_path) | |
133 | { | |
134 | int fd, addr_len, rval, errors; | |
135 | char msg[2]; | |
136 | struct sockaddr_storage addr; | |
137 | struct sockaddr_in *addr_in = (struct sockaddr_in *)&addr; | |
138 | struct sockaddr_un *addr_un = (struct sockaddr_un *)&addr; | |
139 | mysig_t old_sigpipe; | |
140 | ||
141 | /* 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"); | |
147 | if (len > 255) | |
148 | fatal("Too many bytes to read from PRNGD"); | |
149 | ||
150 | memset(&addr, '\0', sizeof(addr)); | |
151 | ||
152 | 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 | } | |
164 | ||
165 | old_sigpipe = mysignal(SIGPIPE, SIG_IGN); | |
166 | ||
167 | errors = 0; | |
168 | rval = -1; | |
169 | reopen: | |
170 | fd = socket(addr.ss_family, SOCK_STREAM, 0); | |
171 | if (fd == -1) { | |
172 | error("Couldn't create socket: %s", strerror(errno)); | |
173 | goto done; | |
174 | } | |
175 | ||
176 | if (connect(fd, (struct sockaddr*)&addr, addr_len) == -1) { | |
177 | 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 | } | |
184 | 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 | ||
213 | rval = 0; | |
214 | done: | |
215 | mysignal(SIGPIPE, old_sigpipe); | |
216 | if (fd != -1) | |
217 | close(fd); | |
218 | return rval; | |
219 | } | |
220 | ||
221 | double | |
222 | stir_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 | ||
231 | return entropy_estimate; | |
232 | } | |
233 | ||
234 | double | |
235 | stir_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 | ||
243 | return entropy_estimate; | |
244 | #else /* _HAVE_CLOCK */ | |
245 | return 0; | |
246 | #endif /* _HAVE_CLOCK */ | |
247 | } | |
248 | ||
249 | double | |
250 | stir_rusage(int who, double entropy_estimate) | |
251 | { | |
252 | #ifdef HAVE_GETRUSAGE | |
253 | struct rusage ru; | |
254 | ||
255 | if (getrusage(who, &ru) == -1) | |
256 | return 0; | |
257 | ||
258 | RAND_add(&ru, sizeof(ru), entropy_estimate); | |
259 | ||
260 | return entropy_estimate; | |
261 | #else /* _HAVE_GETRUSAGE */ | |
262 | return 0; | |
263 | #endif /* _HAVE_GETRUSAGE */ | |
264 | } | |
265 | ||
266 | static int | |
267 | timeval_diff(struct timeval *t1, struct timeval *t2) | |
268 | { | |
269 | 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 | ||
276 | double | |
277 | hash_command_output(entropy_cmd_t *src, char *hash) | |
278 | { | |
279 | char buf[8192]; | |
280 | fd_set rdset; | |
281 | int bytes_read, cmd_eof, error_abort, msec_elapsed, p[2]; | |
282 | int status, total_bytes_read; | |
283 | static int devnull = -1; | |
284 | pid_t pid; | |
285 | SHA_CTX sha; | |
286 | struct timeval tv_start, tv_current; | |
287 | ||
288 | debug3("Reading output from \'%s\'", src->cmdstring); | |
289 | ||
290 | if (devnull == -1) { | |
291 | devnull = open("/dev/null", O_RDWR); | |
292 | if (devnull == -1) | |
293 | fatal("Couldn't open /dev/null: %s", | |
294 | strerror(errno)); | |
295 | } | |
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)); | |
317 | ||
318 | debug("(child) Couldn't exec '%s': %s", | |
319 | src->cmdstring, strerror(errno)); | |
320 | _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); | |
331 | ||
332 | cmd_eof = error_abort = msec_elapsed = total_bytes_read = 0; | |
333 | while (!error_abort && !cmd_eof) { | |
334 | int ret; | |
335 | struct timeval tv; | |
336 | int msec_remaining; | |
337 | ||
338 | (void) gettimeofday(&tv_current, 0); | |
339 | msec_elapsed = timeval_diff(&tv_start, &tv_current); | |
340 | 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); | |
348 | tv.tv_sec = msec_remaining / 1000; | |
349 | tv.tv_usec = (msec_remaining % 1000) * 1000; | |
350 | ||
351 | ret = select(p[0] + 1, &rdset, NULL, NULL, &tv); | |
352 | ||
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 */ | |
379 | debug("Command '%s': select() failed: %s", | |
380 | src->cmdstring, strerror(errno)); | |
381 | 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) { | |
393 | error("Couldn't wait for child '%s' completion: %s", | |
394 | src->cmdstring, strerror(errno)); | |
395 | return 0.0; | |
396 | } | |
397 | ||
398 | RAND_add(&status, sizeof(&status), 0.0); | |
399 | ||
400 | if (error_abort) { | |
401 | /* | |
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 | */ | |
406 | debug2("Command '%s' timed out", src->cmdstring); | |
407 | src->sticky_badness *= 2; | |
408 | src->badness = src->sticky_badness; | |
409 | return total_bytes_read; | |
410 | } | |
411 | ||
412 | if (WIFEXITED(status)) { | |
413 | if (WEXITSTATUS(status) == 0) { | |
414 | return total_bytes_read; | |
415 | } else { | |
416 | debug2("Command '%s' exit status was %d", | |
417 | src->cmdstring, WEXITSTATUS(status)); | |
418 | src->badness = src->sticky_badness = 128; | |
419 | return 0.0; | |
420 | } | |
421 | } else if (WIFSIGNALED(status)) { | |
422 | debug2("Command '%s' returned on uncaught signal %d !", | |
423 | src->cmdstring, status); | |
424 | src->badness = src->sticky_badness = 128; | |
425 | return 0.0; | |
426 | } else | |
427 | return 0.0; | |
428 | } | |
429 | ||
430 | double | |
431 | stir_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 | ||
458 | double | |
459 | stir_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; | |
503 | } | |
504 | ||
505 | /* | |
506 | * prng seedfile functions | |
507 | */ | |
508 | int | |
509 | prng_check_seedfile(char *filename) | |
510 | { | |
511 | struct stat st; | |
512 | ||
513 | /* | |
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 | */ | |
519 | if (lstat(filename, &st) == -1) { | |
520 | /* Give up on hard errors */ | |
521 | if (errno != ENOENT) | |
522 | debug("WARNING: Couldn't stat random seed file " | |
523 | "\"%.100s\": %s", filename, strerror(errno)); | |
524 | return 0; | |
525 | } | |
526 | ||
527 | /* regular file? */ | |
528 | if (!S_ISREG(st.st_mode)) | |
529 | fatal("PRNG seedfile %.100s is not a regular file", | |
530 | filename); | |
531 | ||
532 | /* mode 0600, owned by root or the current user? */ | |
533 | if (((st.st_mode & 0177) != 0) || !(st.st_uid == getuid())) { | |
534 | debug("WARNING: PRNG seedfile %.100s must be mode 0600, " | |
535 | "owned by uid %d", filename, getuid()); | |
536 | return 0; | |
537 | } | |
538 | ||
539 | return 1; | |
540 | } | |
541 | ||
542 | void | |
543 | prng_write_seedfile(void) | |
544 | { | |
545 | int fd; | |
546 | char seed[SEED_FILE_SIZE], filename[MAXPATHLEN]; | |
547 | struct passwd *pw; | |
548 | ||
549 | pw = getpwuid(getuid()); | |
550 | if (pw == NULL) | |
551 | fatal("Couldn't get password entry for current user " | |
552 | "(%i): %s", getuid(), strerror(errno)); | |
553 | ||
554 | /* Try to ensure that the parent directory is there */ | |
555 | snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir, | |
556 | _PATH_SSH_USER_DIR); | |
557 | mkdir(filename, 0700); | |
558 | ||
559 | snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir, | |
560 | SSH_PRNG_SEED_FILE); | |
561 | ||
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) { | |
570 | debug("WARNING: couldn't access PRNG seedfile %.100s " | |
571 | "(%.100s)", filename, strerror(errno)); | |
572 | } else { | |
573 | if (atomicio(write, fd, &seed, sizeof(seed)) < sizeof(seed)) | |
574 | fatal("problem writing PRNG seedfile %.100s " | |
575 | "(%.100s)", filename, strerror(errno)); | |
576 | close(fd); | |
577 | } | |
578 | } | |
579 | ||
580 | void | |
581 | prng_read_seedfile(void) | |
582 | { | |
583 | int fd; | |
584 | char seed[SEED_FILE_SIZE], filename[MAXPATHLEN]; | |
585 | struct passwd *pw; | |
586 | ||
587 | pw = getpwuid(getuid()); | |
588 | if (pw == NULL) | |
589 | fatal("Couldn't get password entry for current user " | |
590 | "(%i): %s", getuid(), strerror(errno)); | |
591 | ||
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)) { | |
598 | verbose("Random seed file not found or invalid, ignoring."); | |
599 | return; | |
600 | } | |
601 | ||
602 | /* open the file and read in the seed */ | |
603 | fd = open(filename, O_RDONLY); | |
604 | if (fd == -1) | |
605 | fatal("could not open PRNG seedfile %.100s (%.100s)", | |
606 | filename, strerror(errno)); | |
607 | ||
608 | if (atomicio(read, fd, &seed, sizeof(seed)) < sizeof(seed)) { | |
609 | verbose("invalid or short read from PRNG seedfile " | |
610 | "%.100s - ignoring", filename); | |
611 | 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 | */ | |
623 | int | |
624 | prng_read_commands(char *cmdfilename) | |
625 | { | |
626 | char cmd[SEED_FILE_SIZE], *cp, line[1024], path[SEED_FILE_SIZE]; | |
627 | double est; | |
628 | entropy_cmd_t *entcmd; | |
629 | FILE *f; | |
630 | int cur_cmd, linenum, num_cmds, arg; | |
631 | ||
632 | if ((f = fopen(cmdfilename, "r")) == NULL) { | |
633 | fatal("couldn't read entropy commands file %.100s: %.100s", | |
634 | cmdfilename, strerror(errno)); | |
635 | } | |
636 | ||
637 | num_cmds = 64; | |
638 | entcmd = xmalloc(num_cmds * sizeof(entropy_cmd_t)); | |
639 | memset(entcmd, '\0', num_cmds * sizeof(entropy_cmd_t)); | |
640 | ||
641 | /* Read in file */ | |
642 | cur_cmd = linenum = 0; | |
643 | while (fgets(line, sizeof(line), f)) { | |
644 | linenum++; | |
645 | ||
646 | /* Skip leading whitespace, blank lines and comments */ | |
647 | cp = line + strspn(line, WHITESPACE); | |
648 | if ((*cp == 0) || (*cp == '#')) | |
649 | continue; /* done with this line */ | |
650 | ||
651 | /* | |
652 | * The first non-whitespace char should be a double quote | |
653 | * delimiting the commandline | |
654 | */ | |
655 | if (*cp != '"') { | |
656 | error("bad entropy command, %.100s line %d", | |
657 | cmdfilename, linenum); | |
658 | continue; | |
659 | } | |
660 | ||
661 | /* | |
662 | * First token, command args (incl. argv[0]) in double | |
663 | * quotes | |
664 | */ | |
665 | cp = strtok(cp, "\""); | |
666 | if (cp == NULL) { | |
667 | error("missing or bad command string, %.100s " | |
668 | "line %d -- ignored", cmdfilename, linenum); | |
669 | continue; | |
670 | } | |
671 | strlcpy(cmd, cp, sizeof(cmd)); | |
672 | ||
673 | /* Second token, full command path */ | |
674 | if ((cp = strtok(NULL, WHITESPACE)) == NULL) { | |
675 | error("missing command path, %.100s " | |
676 | "line %d -- ignored", cmdfilename, linenum); | |
677 | continue; | |
678 | } | |
679 | ||
680 | /* Did configure mark this as dead? */ | |
681 | if (strncmp("undef", cp, 5) == 0) | |
682 | continue; | |
683 | ||
684 | strlcpy(path, cp, sizeof(path)); | |
685 | ||
686 | /* Third token, entropy rate estimate for this command */ | |
687 | if ((cp = strtok(NULL, WHITESPACE)) == NULL) { | |
688 | error("missing entropy estimate, %.100s " | |
689 | "line %d -- ignored", cmdfilename, linenum); | |
690 | continue; | |
691 | } | |
692 | est = strtod(cp, NULL); | |
693 | ||
694 | /* end of line */ | |
695 | if ((cp = strtok(NULL, WHITESPACE)) != NULL) { | |
696 | error("garbage at end of line %d in %.100s " | |
697 | "-- ignored", linenum, cmdfilename); | |
698 | 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; | |
707 | do { | |
708 | entcmd[cur_cmd].args[arg] = xstrdup(cp); | |
709 | arg++; | |
710 | } while(arg < NUM_ARGS && (cp = strtok(NULL, WHITESPACE))); | |
711 | ||
712 | if (strtok(NULL, WHITESPACE)) | |
713 | error("ignored extra commands (max %d), %.100s " | |
714 | "line %d", NUM_ARGS, cmdfilename, linenum); | |
715 | ||
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 | ||
725 | /* | |
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 | */ | |
730 | if (cur_cmd == num_cmds) { | |
731 | num_cmds *= 2; | |
732 | entcmd = xrealloc(entcmd, num_cmds * | |
733 | sizeof(entropy_cmd_t)); | |
734 | } | |
735 | } | |
736 | ||
737 | /* zero the last entry */ | |
738 | memset(&entcmd[cur_cmd], '\0', sizeof(entropy_cmd_t)); | |
739 | ||
740 | /* trim to size */ | |
741 | entropy_cmds = xrealloc(entcmd, (cur_cmd + 1) * | |
742 | sizeof(entropy_cmd_t)); | |
743 | ||
744 | debug("Loaded %d entropy commands from %.100s", cur_cmd, | |
745 | cmdfilename); | |
746 | ||
747 | return cur_cmd < MIN_ENTROPY_SOURCES ? -1 : 0; | |
748 | } | |
749 | ||
750 | void | |
751 | usage(void) | |
752 | { | |
753 | fprintf(stderr, "Usage: %s [options]\n", __progname); | |
754 | fprintf(stderr, " -v Verbose; display verbose debugging messages.\n"); | |
755 | fprintf(stderr, " Multiple -v increases verbosity.\n"); | |
756 | fprintf(stderr, " -x Force output in hexidecimal (for debugging)\n"); | |
757 | fprintf(stderr, " -X Force output in binary\n"); | |
758 | fprintf(stderr, " -b bytes Number of bytes to output (default %d)\n", | |
759 | OUTPUT_SEED_SIZE); | |
760 | } | |
761 | ||
762 | int | |
763 | main(int argc, char **argv) | |
764 | { | |
765 | unsigned char *buf; | |
766 | int ret, ch, debug_level, output_hex, bytes; | |
767 | extern char *optarg; | |
768 | LogLevel ll; | |
769 | ||
770 | __progname = get_progname(argv[0]); | |
771 | log_init(argv[0], SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_USER, 1); | |
772 | ||
773 | ll = SYSLOG_LEVEL_INFO; | |
774 | debug_level = output_hex = 0; | |
775 | bytes = OUTPUT_SEED_SIZE; | |
776 | ||
777 | /* Don't write binary data to a tty, unless we are forced to */ | |
778 | if (isatty(STDOUT_FILENO)) | |
779 | output_hex = 1; | |
780 | ||
781 | while ((ch = getopt(argc, argv, "vxXhb:")) != -1) { | |
782 | switch (ch) { | |
783 | case 'v': | |
784 | if (debug_level < 3) | |
785 | ll = SYSLOG_LEVEL_DEBUG1 + debug_level++; | |
786 | break; | |
787 | case 'x': | |
788 | output_hex = 1; | |
789 | break; | |
790 | case 'X': | |
791 | output_hex = 0; | |
792 | break; | |
793 | case 'b': | |
794 | if ((bytes = atoi(optarg)) <= 0) | |
795 | fatal("Invalid number of output bytes"); | |
796 | break; | |
797 | case 'h': | |
798 | usage(); | |
799 | exit(0); | |
800 | default: | |
801 | error("Invalid commandline option"); | |
802 | usage(); | |
803 | } | |
804 | } | |
805 | ||
806 | log_init(argv[0], ll, SYSLOG_FACILITY_USER, 1); | |
807 | ||
808 | #ifdef USE_SEED_FILES | |
809 | prng_read_seedfile(); | |
810 | #endif | |
811 | ||
812 | buf = xmalloc(bytes); | |
813 | ||
814 | /* | |
815 | * Seed the RNG from wherever we can | |
816 | */ | |
817 | ||
818 | /* Take whatever is on the stack, but don't credit it */ | |
819 | RAND_add(buf, bytes, 0); | |
820 | ||
821 | debug("Seeded RNG with %i bytes from system calls", | |
822 | (int)stir_from_system()); | |
823 | ||
824 | #ifdef PRNGD_PORT | |
825 | if (get_random_bytes_prngd(buf, bytes, PRNGD_PORT, NULL) == -1) | |
826 | fatal("Entropy collection failed"); | |
827 | RAND_add(buf, bytes, bytes); | |
828 | #elif defined(PRNGD_SOCKET) | |
829 | if (get_random_bytes_prngd(buf, bytes, 0, PRNGD_SOCKET) == -1) | |
830 | fatal("Entropy collection failed"); | |
831 | RAND_add(buf, bytes, bytes); | |
832 | #else | |
833 | /* Read in collection commands */ | |
834 | if (prng_read_commands(SSH_PRNG_COMMAND_FILE) == -1) | |
835 | fatal("PRNG initialisation failed -- exiting."); | |
836 | debug("Seeded RNG with %i bytes from programs", | |
837 | (int)stir_from_programs()); | |
838 | #endif | |
839 | ||
840 | #ifdef USE_SEED_FILES | |
841 | prng_write_seedfile(); | |
842 | #endif | |
843 | ||
844 | /* | |
845 | * Write the seed to stdout | |
846 | */ | |
847 | ||
848 | if (!RAND_status()) | |
849 | fatal("Not enough entropy in RNG"); | |
850 | ||
851 | RAND_bytes(buf, bytes); | |
852 | ||
853 | if (output_hex) { | |
854 | for(ret = 0; ret < bytes; ret++) | |
855 | printf("%02x", (unsigned char)(buf[ret])); | |
856 | printf("\n"); | |
857 | } else | |
858 | ret = atomicio(write, STDOUT_FILENO, buf, bytes); | |
859 | ||
860 | memset(buf, '\0', bytes); | |
861 | xfree(buf); | |
862 | ||
863 | return ret == bytes ? 0 : 1; | |
864 | } | |
865 |