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bfc9a610 | 1 | /* |
2 | * Copyright (c) 2000 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 | * 3. All advertising materials mentioning features or use of this software | |
13 | * must display the following acknowledgement: | |
14 | * This product includes software developed by Markus Friedl. | |
15 | * 4. The name of the author may not be used to endorse or promote products | |
16 | * derived from this software without specific prior written permission. | |
17 | * | |
18 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR | |
19 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES | |
20 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. | |
21 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, | |
22 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
23 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
24 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
25 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
26 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF | |
27 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
28 | */ | |
29 | ||
30 | #include "includes.h" | |
31 | ||
32 | #include "ssh.h" | |
33 | #include "xmalloc.h" | |
34 | ||
35484284 | 35 | #include <openssl/rand.h> |
36 | #include <openssl/sha.h> | |
bfc9a610 | 37 | |
38 | RCSID("$Id$"); | |
39 | ||
40 | #ifdef EGD_SOCKET | |
41 | #ifndef offsetof | |
42 | # define offsetof(type, member) ((size_t) &((type *)0)->member) | |
43 | #endif | |
44 | /* Collect entropy from EGD */ | |
45 | void get_random_bytes(unsigned char *buf, int len) | |
46 | { | |
47 | static int egd_socket = -1; | |
48 | int c; | |
49 | char egd_message[2] = { 0x02, 0x00 }; | |
50 | struct sockaddr_un addr; | |
51 | int addr_len; | |
52 | ||
53 | memset(&addr, '\0', sizeof(addr)); | |
54 | addr.sun_family = AF_UNIX; | |
55 | ||
56 | /* FIXME: compile time check? */ | |
57 | if (sizeof(EGD_SOCKET) > sizeof(addr.sun_path)) | |
58 | fatal("Random pool path is too long"); | |
59 | ||
60 | strcpy(addr.sun_path, EGD_SOCKET); | |
61 | ||
62 | addr_len = offsetof(struct sockaddr_un, sun_path) + sizeof(EGD_SOCKET); | |
63 | ||
64 | if (egd_socket == -1) { | |
65 | egd_socket = socket(AF_UNIX, SOCK_STREAM, 0); | |
66 | if (egd_socket == -1) | |
67 | fatal("Couldn't create AF_UNIX socket: %s", strerror(errno)); | |
68 | if (connect(egd_socket, (struct sockaddr*)&addr, addr_len) == -1) | |
69 | fatal("Couldn't connect to EGD socket \"%s\": %s", addr.sun_path, strerror(errno)); | |
70 | } | |
71 | ||
72 | if (len > 255) | |
73 | fatal("Too many bytes to read from EGD"); | |
74 | ||
75 | /* Send blocking read request to EGD */ | |
76 | egd_message[1] = len; | |
77 | ||
78 | c = atomicio(write, egd_socket, egd_message, sizeof(egd_message)); | |
79 | if (c == -1) | |
80 | fatal("Couldn't write to EGD socket \"%s\": %s", EGD_SOCKET, strerror(errno)); | |
81 | ||
82 | c = atomicio(read, egd_socket, buf, len); | |
83 | if (c <= 0) | |
84 | fatal("Couldn't read from EGD socket \"%s\": %s", EGD_SOCKET, strerror(errno)); | |
85 | ||
86 | close(EGD_SOCKET); | |
87 | } | |
88 | #else /* !EGD_SOCKET */ | |
89 | #ifdef RANDOM_POOL | |
90 | /* Collect entropy from /dev/urandom or pipe */ | |
91 | void get_random_bytes(unsigned char *buf, int len) | |
92 | { | |
93 | static int random_pool = -1; | |
94 | int c; | |
95 | ||
96 | if (random_pool == -1) { | |
97 | random_pool = open(RANDOM_POOL, O_RDONLY); | |
98 | if (random_pool == -1) | |
99 | fatal("Couldn't open random pool \"%s\": %s", RANDOM_POOL, strerror(errno)); | |
100 | } | |
101 | ||
bfc9a610 | 102 | c = atomicio(read, random_pool, buf, len); |
103 | if (c <= 0) | |
104 | fatal("Couldn't read from random pool \"%s\": %s", RANDOM_POOL, strerror(errno)); | |
105 | } | |
106 | #endif /* RANDOM_POOL */ | |
107 | #endif /* EGD_SOCKET */ | |
108 | ||
109 | #if !defined(EGD_SOCKET) && !defined(RANDOM_POOL) | |
110 | /* | |
111 | * FIXME: proper entropy estimations. All current values are guesses | |
b7a87eea | 112 | * FIXME: (ATL) do estimates at compile time? |
bfc9a610 | 113 | * FIXME: More entropy sources |
114 | */ | |
115 | ||
b7a87eea | 116 | /* slow command timeouts (all in milliseconds) */ |
117 | /* static int entropy_timeout_default = ENTROPY_TIMEOUT_MSEC; */ | |
118 | static int entropy_timeout_current = ENTROPY_TIMEOUT_MSEC; | |
119 | ||
120 | static int prng_seed_loaded = 0; | |
d3083fbd | 121 | static int prng_seed_saved = 0; |
122 | static int prng_commands_loaded = 0; | |
bfc9a610 | 123 | |
124 | typedef struct | |
125 | { | |
126 | /* Proportion of data that is entropy */ | |
127 | double rate; | |
b7a87eea | 128 | /* Counter goes positive if this command times out */ |
129 | unsigned int badness; | |
130 | /* Increases by factor of two each timeout */ | |
131 | unsigned int sticky_badness; | |
bfc9a610 | 132 | /* Path to executable */ |
d3083fbd | 133 | char *path; |
bfc9a610 | 134 | /* argv to pass to executable */ |
d3083fbd | 135 | char *args[5]; |
ad85db64 | 136 | /* full command string (debug) */ |
137 | char *cmdstring; | |
bfc9a610 | 138 | } entropy_source_t; |
139 | ||
b7a87eea | 140 | double stir_from_system(void); |
141 | double stir_from_programs(void); | |
142 | double stir_gettimeofday(double entropy_estimate); | |
143 | double stir_clock(double entropy_estimate); | |
144 | double stir_rusage(int who, double entropy_estimate); | |
145 | double hash_output_from_command(entropy_source_t *src, char *hash); | |
146 | ||
d3083fbd | 147 | /* this is initialised from a file, by prng_read_commands() */ |
148 | entropy_source_t *entropy_sources = NULL; | |
149 | #define MIN_ENTROPY_SOURCES 16 | |
150 | ||
bfc9a610 | 151 | |
bfc9a610 | 152 | double |
153 | stir_from_system(void) | |
154 | { | |
155 | double total_entropy_estimate; | |
156 | long int i; | |
157 | ||
158 | total_entropy_estimate = 0; | |
159 | ||
160 | i = getpid(); | |
161 | RAND_add(&i, sizeof(i), 0.1); | |
162 | total_entropy_estimate += 0.1; | |
163 | ||
164 | i = getppid(); | |
165 | RAND_add(&i, sizeof(i), 0.1); | |
166 | total_entropy_estimate += 0.1; | |
167 | ||
168 | i = getuid(); | |
169 | RAND_add(&i, sizeof(i), 0.0); | |
170 | i = getgid(); | |
171 | RAND_add(&i, sizeof(i), 0.0); | |
172 | ||
173 | total_entropy_estimate += stir_gettimeofday(1.0); | |
174 | total_entropy_estimate += stir_clock(0.2); | |
175 | total_entropy_estimate += stir_rusage(RUSAGE_SELF, 2.0); | |
176 | ||
177 | return(total_entropy_estimate); | |
178 | } | |
179 | ||
180 | double | |
181 | stir_from_programs(void) | |
182 | { | |
183 | int i; | |
184 | int c; | |
185 | double entropy_estimate; | |
186 | double total_entropy_estimate; | |
187 | char hash[SHA_DIGEST_LENGTH]; | |
188 | ||
189 | /* | |
190 | * Run through list of programs twice to catch differences | |
191 | */ | |
192 | total_entropy_estimate = 0; | |
193 | for(i = 0; i < 2; i++) { | |
194 | c = 0; | |
195 | while (entropy_sources[c].path != NULL) { | |
bfc9a610 | 196 | |
b7a87eea | 197 | if (!entropy_sources[c].badness) { |
198 | /* Hash output from command */ | |
199 | entropy_estimate = hash_output_from_command(&entropy_sources[c], hash); | |
200 | ||
201 | /* Scale back entropy estimate according to command's rate */ | |
202 | entropy_estimate *= entropy_sources[c].rate; | |
bfc9a610 | 203 | |
b7a87eea | 204 | /* Upper bound of entropy estimate is SHA_DIGEST_LENGTH */ |
205 | if (entropy_estimate > SHA_DIGEST_LENGTH) | |
206 | entropy_estimate = SHA_DIGEST_LENGTH; | |
bfc9a610 | 207 | |
208 | /* * Scale back estimates for subsequent passes through list */ | |
b7a87eea | 209 | entropy_estimate /= 10.0 * (i + 1.0); |
bfc9a610 | 210 | |
b7a87eea | 211 | /* Stir it in */ |
212 | RAND_add(hash, sizeof(hash), entropy_estimate); | |
bfc9a610 | 213 | |
214 | /* FIXME: turn this off later */ | |
215 | #if 1 | |
ad85db64 | 216 | debug("Got %0.2f bytes of entropy from '%s'", entropy_estimate, |
217 | entropy_sources[c].cmdstring); | |
bfc9a610 | 218 | #endif |
219 | ||
b7a87eea | 220 | total_entropy_estimate += entropy_estimate; |
bfc9a610 | 221 | |
222 | /* Execution times should be a little unpredictable */ | |
b7a87eea | 223 | total_entropy_estimate += stir_gettimeofday(0.05); |
224 | total_entropy_estimate += stir_clock(0.05); | |
225 | total_entropy_estimate += stir_rusage(RUSAGE_SELF, 0.1); | |
226 | total_entropy_estimate += stir_rusage(RUSAGE_CHILDREN, 0.1); | |
227 | } else { | |
228 | /* FIXME: turn this off later */ | |
229 | #if 1 | |
ad85db64 | 230 | debug("Command '%s' disabled (badness %d)", |
231 | entropy_sources[c].cmdstring, entropy_sources[c].badness); | |
b7a87eea | 232 | #endif |
233 | ||
234 | if (entropy_sources[c].badness > 0) | |
235 | entropy_sources[c].badness--; | |
236 | } | |
237 | ||
bfc9a610 | 238 | c++; |
239 | } | |
240 | } | |
241 | ||
242 | return(total_entropy_estimate); | |
243 | } | |
244 | ||
245 | double | |
246 | stir_gettimeofday(double entropy_estimate) | |
247 | { | |
248 | struct timeval tv; | |
249 | ||
250 | if (gettimeofday(&tv, NULL) == -1) | |
251 | fatal("Couldn't gettimeofday: %s", strerror(errno)); | |
252 | ||
253 | RAND_add(&tv, sizeof(tv), entropy_estimate); | |
254 | ||
255 | return(entropy_estimate); | |
256 | } | |
257 | ||
258 | double | |
259 | stir_clock(double entropy_estimate) | |
260 | { | |
261 | #ifdef HAVE_CLOCK | |
262 | clock_t c; | |
263 | ||
264 | c = clock(); | |
265 | RAND_add(&c, sizeof(c), entropy_estimate); | |
266 | ||
267 | return(entropy_estimate); | |
268 | #else /* _HAVE_CLOCK */ | |
269 | return(0); | |
270 | #endif /* _HAVE_CLOCK */ | |
271 | } | |
272 | ||
273 | double | |
274 | stir_rusage(int who, double entropy_estimate) | |
275 | { | |
276 | #ifdef HAVE_GETRUSAGE | |
277 | struct rusage ru; | |
278 | ||
b7a87eea | 279 | if (getrusage(who, &ru) == -1) |
bfc9a610 | 280 | fatal("Couldn't getrusage: %s", strerror(errno)); |
281 | ||
282 | RAND_add(&ru, sizeof(ru), 0.1); | |
283 | ||
284 | return(entropy_estimate); | |
285 | #else /* _HAVE_GETRUSAGE */ | |
286 | return(0); | |
287 | #endif /* _HAVE_GETRUSAGE */ | |
288 | } | |
289 | ||
ad85db64 | 290 | |
291 | static | |
292 | int | |
293 | _get_timeval_msec_difference(struct timeval *t1, struct timeval *t2) { | |
294 | int secdiff, usecdiff; | |
295 | ||
296 | secdiff = t2->tv_sec - t1->tv_sec; | |
297 | usecdiff = (secdiff*1000000) + (t2->tv_usec - t1->tv_usec); | |
298 | return (int)(usecdiff / 1000); | |
299 | } | |
300 | ||
bfc9a610 | 301 | double |
b7a87eea | 302 | hash_output_from_command(entropy_source_t *src, char *hash) |
bfc9a610 | 303 | { |
304 | static int devnull = -1; | |
305 | int p[2]; | |
b7a87eea | 306 | fd_set rdset; |
307 | int cmd_eof = 0, error_abort = 0; | |
ad85db64 | 308 | struct timeval tv_start, tv_current; |
309 | int msec_elapsed = 0; | |
bfc9a610 | 310 | pid_t pid; |
311 | int status; | |
ad85db64 | 312 | char buf[16384]; |
bfc9a610 | 313 | int bytes_read; |
314 | int total_bytes_read; | |
315 | SHA_CTX sha; | |
316 | ||
317 | if (devnull == -1) { | |
318 | devnull = open("/dev/null", O_RDWR); | |
319 | if (devnull == -1) | |
320 | fatal("Couldn't open /dev/null: %s", strerror(errno)); | |
321 | } | |
322 | ||
323 | if (pipe(p) == -1) | |
324 | fatal("Couldn't open pipe: %s", strerror(errno)); | |
325 | ||
ad85db64 | 326 | (void)gettimeofday(&tv_start, NULL); /* record start time */ |
327 | ||
bfc9a610 | 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 */ | |
b7a87eea | 335 | dup2(devnull, STDIN_FILENO); |
336 | dup2(p[1], STDOUT_FILENO); | |
337 | dup2(p[1], STDERR_FILENO); | |
bfc9a610 | 338 | close(p[0]); |
339 | close(p[1]); | |
340 | close(devnull); | |
341 | ||
b7a87eea | 342 | execv(src->path, (char**)(src->args)); |
ad85db64 | 343 | debug("(child) Couldn't exec '%s': %s", src->cmdstring, |
344 | strerror(errno)); | |
b7a87eea | 345 | src->badness = src->sticky_badness = 128; |
bfc9a610 | 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 | total_bytes_read = 0; | |
b7a87eea | 358 | |
359 | while (!error_abort && !cmd_eof) { | |
360 | int ret; | |
361 | struct timeval tv; | |
ad85db64 | 362 | int msec_remaining; |
363 | ||
364 | (void) gettimeofday(&tv_current, 0); | |
365 | msec_elapsed = _get_timeval_msec_difference( | |
366 | &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; | |
b7a87eea | 372 | |
373 | FD_ZERO(&rdset); | |
374 | FD_SET(p[0], &rdset); | |
ad85db64 | 375 | tv.tv_sec = msec_remaining / 1000; |
376 | tv.tv_usec = (msec_remaining % 1000) * 1000; | |
b7a87eea | 377 | |
378 | ret = select(p[0]+1, &rdset, NULL, NULL, &tv); | |
ad85db64 | 379 | |
b7a87eea | 380 | switch (ret) { |
381 | case 0: | |
382 | /* timer expired */ | |
383 | error_abort = 1; | |
384 | break; | |
385 | ||
386 | case 1: | |
387 | /* command input */ | |
388 | bytes_read = read(p[0], buf, sizeof(buf)); | |
389 | if (bytes_read == -1) { | |
390 | error_abort = 1; | |
391 | break; | |
392 | } | |
ad85db64 | 393 | if (bytes_read) { |
394 | SHA1_Update(&sha, buf, bytes_read); | |
395 | total_bytes_read += bytes_read; | |
396 | RAND_add(&bytes_read, sizeof(&bytes_read), 0.0); | |
397 | } else | |
398 | cmd_eof = 1; | |
b7a87eea | 399 | |
400 | break; | |
401 | ||
402 | case -1: | |
403 | default: | |
ad85db64 | 404 | debug("Command '%s': select() failed: %s", src->cmdstring, |
405 | strerror(errno)); | |
b7a87eea | 406 | error_abort = 1; |
407 | break; | |
408 | } /* switch ret */ | |
409 | ||
410 | RAND_add(&tv, sizeof(&tv), 0.0); | |
411 | } /* while !error_abort && !cmd_eof */ | |
412 | ||
bfc9a610 | 413 | SHA1_Final(hash, &sha); |
414 | ||
415 | close(p[0]); | |
ad85db64 | 416 | |
417 | debug("Time elapsed: %d msec", msec_elapsed); | |
bfc9a610 | 418 | |
419 | if (waitpid(pid, &status, 0) == -1) { | |
ad85db64 | 420 | debug("Couldn't wait for child '%s' completion: %s", src->cmdstring, |
421 | strerror(errno)); | |
b7a87eea | 422 | return(0.0); |
bfc9a610 | 423 | } |
424 | ||
425 | RAND_add(&status, sizeof(&status), 0.0); | |
426 | ||
b7a87eea | 427 | if (error_abort) { |
428 | /* closing p[0] on timeout causes the entropy command to | |
429 | * SIGPIPE. Take whatever output we got, and mark this command | |
430 | * as slow */ | |
ad85db64 | 431 | debug("Command '%s' timed out", src->cmdstring); |
b7a87eea | 432 | src->sticky_badness *= 2; |
433 | src->badness = src->sticky_badness; | |
bfc9a610 | 434 | return(total_bytes_read); |
b7a87eea | 435 | } |
436 | ||
437 | if (WIFEXITED(status)) { | |
438 | if (WEXITSTATUS(status)==0) { | |
439 | return(total_bytes_read); | |
440 | } else { | |
441 | debug("Exit status was %d", WEXITSTATUS(status)); | |
442 | src->badness = src->sticky_badness = 128; | |
443 | return (0.0); | |
444 | } | |
445 | } else if (WIFSIGNALED(status)) { | |
446 | debug("Returned on uncaught signal %d !", status); | |
447 | src->badness = src->sticky_badness = 128; | |
448 | return(0.0); | |
449 | } else | |
450 | return(0.0); | |
451 | } | |
452 | ||
453 | /* | |
454 | * prng seedfile functions | |
455 | */ | |
456 | int | |
457 | prng_check_seedfile(char *filename) { | |
458 | ||
459 | struct stat st; | |
460 | ||
461 | /* FIXME raceable: eg replace seed between this stat and subsequent open */ | |
462 | /* Not such a problem because we don't trust the seed file anyway */ | |
463 | if (lstat(filename, &st) == -1) { | |
464 | /* Fail on hard errors */ | |
465 | if (errno != ENOENT) | |
466 | fatal("Couldn't stat random seed file \"%s\": %s", filename, | |
467 | strerror(errno)); | |
468 | ||
469 | return(0); | |
470 | } | |
471 | ||
472 | /* regular file? */ | |
473 | if (!S_ISREG(st.st_mode)) | |
474 | fatal("PRNG seedfile %.100s is not a regular file", filename); | |
475 | ||
476 | /* mode 0600, owned by root or the current user? */ | |
d02a3a00 | 477 | if (((st.st_mode & 0177) != 0) || !(st.st_uid == getuid())) |
b7a87eea | 478 | fatal("PRNG seedfile %.100s must be mode 0600, owned by uid %d", |
479 | filename, getuid()); | |
480 | ||
481 | return(1); | |
482 | } | |
483 | ||
484 | void | |
485 | prng_write_seedfile(void) { | |
486 | int fd; | |
487 | char seed[1024]; | |
488 | char filename[1024]; | |
489 | struct passwd *pw; | |
490 | ||
491 | /* Don't bother if we have already saved a seed */ | |
492 | if (prng_seed_saved) | |
493 | return; | |
494 | ||
52bcc044 | 495 | prng_seed_saved = 1; |
496 | ||
b7a87eea | 497 | pw = getpwuid(getuid()); |
498 | if (pw == NULL) | |
499 | fatal("Couldn't get password entry for current user (%i): %s", | |
500 | getuid(), strerror(errno)); | |
501 | ||
502 | /* Try to ensure that the parent directory is there */ | |
503 | snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir, | |
504 | SSH_USER_DIR); | |
505 | mkdir(filename, 0700); | |
506 | ||
507 | snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir, | |
508 | SSH_PRNG_SEED_FILE); | |
509 | ||
510 | debug("writing PRNG seed to file %.100s", filename); | |
511 | ||
512 | RAND_bytes(seed, sizeof(seed)); | |
513 | ||
514 | /* Don't care if the seed doesn't exist */ | |
515 | prng_check_seedfile(filename); | |
516 | ||
517 | if ((fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0600)) == -1) | |
518 | fatal("couldn't access PRNG seedfile %.100s (%.100s)", filename, | |
519 | strerror(errno)); | |
520 | ||
521 | if (atomicio(write, fd, &seed, sizeof(seed)) != sizeof(seed)) | |
522 | fatal("problem writing PRNG seedfile %.100s (%.100s)", filename, | |
523 | strerror(errno)); | |
524 | ||
525 | close(fd); | |
526 | } | |
527 | ||
528 | void | |
529 | prng_read_seedfile(void) { | |
530 | int fd; | |
531 | char seed[1024]; | |
532 | char filename[1024]; | |
533 | struct passwd *pw; | |
534 | ||
535 | pw = getpwuid(getuid()); | |
536 | if (pw == NULL) | |
537 | fatal("Couldn't get password entry for current user (%i): %s", | |
538 | getuid(), strerror(errno)); | |
539 | ||
540 | snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir, | |
541 | SSH_PRNG_SEED_FILE); | |
542 | ||
543 | debug("loading PRNG seed from file %.100s", filename); | |
544 | ||
545 | if (!prng_check_seedfile(filename)) { | |
546 | verbose("Random seed file not found, creating new"); | |
547 | prng_write_seedfile(); | |
548 | ||
549 | /* Reseed immediatly */ | |
550 | (void)stir_from_system(); | |
551 | (void)stir_from_programs(); | |
552 | return; | |
553 | } | |
554 | ||
555 | /* open the file and read in the seed */ | |
556 | fd = open(filename, O_RDONLY); | |
557 | if (fd == -1) | |
558 | fatal("could not open PRNG seedfile %.100s (%.100s)", filename, | |
559 | strerror(errno)); | |
560 | ||
561 | if (atomicio(read, fd, &seed, sizeof(seed)) != sizeof(seed)) { | |
562 | verbose("invalid or short read from PRNG seedfile %.100s - ignoring", | |
563 | filename); | |
564 | memset(seed, '\0', sizeof(seed)); | |
565 | } | |
566 | close(fd); | |
567 | ||
568 | /* stir in the seed, with estimated entropy zero */ | |
569 | RAND_add(&seed, sizeof(seed), 0.0); | |
bfc9a610 | 570 | } |
b7a87eea | 571 | |
d3083fbd | 572 | |
573 | /* | |
574 | * entropy command initialisation functions | |
575 | */ | |
576 | #define WHITESPACE " \t\n" | |
577 | ||
578 | int | |
579 | prng_read_commands(char *cmdfilename) | |
580 | { | |
581 | FILE *f; | |
582 | char line[1024]; | |
583 | char cmd[1024], path[256]; | |
584 | double est; | |
585 | char *cp; | |
586 | int linenum; | |
587 | entropy_source_t *entcmd; | |
588 | int num_cmds = 64; | |
589 | int cur_cmd = 0; | |
590 | ||
591 | f = fopen(cmdfilename, "r"); | |
592 | if (!f) { | |
593 | fatal("couldn't read entropy commands file %.100s: %.100s", | |
594 | cmdfilename, strerror(errno)); | |
595 | } | |
596 | ||
597 | linenum = 0; | |
598 | ||
599 | entcmd = (entropy_source_t *)xmalloc(num_cmds * sizeof(entropy_source_t)); | |
600 | memset(entcmd, '\0', num_cmds * sizeof(entropy_source_t)); | |
601 | ||
602 | while (fgets(line, sizeof(line), f)) { | |
603 | linenum++; | |
604 | ||
605 | /* skip leading whitespace, test for blank line or comment */ | |
606 | cp = line + strspn(line, WHITESPACE); | |
607 | if ((*cp == 0) || (*cp == '#')) | |
608 | continue; /* done with this line */ | |
609 | ||
610 | switch (*cp) { | |
611 | int arg; | |
612 | char *argv; | |
613 | ||
614 | case '"': | |
615 | /* first token, command args (incl. argv[0]) in double quotes */ | |
616 | cp = strtok(cp, "\""); | |
617 | if (cp==NULL) { | |
618 | error("missing or bad command string, %.100s line %d -- ignored", | |
619 | cmdfilename, linenum); | |
620 | continue; | |
621 | } | |
622 | strncpy(cmd, cp, sizeof(cmd)); | |
623 | /* second token, full command path */ | |
624 | if ((cp = strtok(NULL, WHITESPACE)) == NULL) { | |
625 | error("missing command path, %.100s line %d -- ignored", | |
626 | cmdfilename, linenum); | |
627 | continue; | |
628 | } | |
629 | if (strncmp("undef", cp, 5)==0) /* did configure mark this as dead? */ | |
630 | continue; | |
631 | ||
632 | strncpy(path, cp, sizeof(path)); | |
633 | /* third token, entropy rate estimate for this command */ | |
634 | if ( (cp = strtok(NULL, WHITESPACE)) == NULL) { | |
635 | error("missing entropy estimate, %.100s line %d -- ignored", | |
636 | cmdfilename, linenum); | |
637 | continue; | |
638 | } | |
639 | est = strtod(cp, &argv);/* FIXME: (ATL) no error checking here */ | |
640 | ||
641 | /* end of line */ | |
642 | if ((cp = strtok(NULL, WHITESPACE)) != NULL) { | |
643 | error("garbage at end of line %d in %.100s -- ignored", | |
644 | linenum, cmdfilename); | |
645 | continue; | |
646 | } | |
647 | ||
ad85db64 | 648 | /* save the command for debug messages */ |
649 | entcmd[cur_cmd].cmdstring = (char*) xmalloc(strlen(cmd)+1); | |
650 | strncpy(entcmd[cur_cmd].cmdstring, cmd, strlen(cmd)+1); | |
651 | ||
d3083fbd | 652 | /* split the command args */ |
653 | cp = strtok(cmd, WHITESPACE); | |
654 | arg = 0; argv = NULL; | |
655 | do { | |
656 | char *s = (char*)xmalloc(strlen(cp)+1); | |
657 | strncpy(s, cp, strlen(cp)+1); | |
658 | entcmd[cur_cmd].args[arg] = s; | |
659 | arg++; | |
660 | } while ((arg < 5) && (cp = strtok(NULL, WHITESPACE))); | |
661 | if (strtok(NULL, WHITESPACE)) | |
662 | error("ignored extra command elements (max 5), %.100s line %d", | |
663 | cmdfilename, linenum); | |
664 | ||
665 | /* copy the command path and rate estimate */ | |
666 | entcmd[cur_cmd].path = (char *)xmalloc(strlen(path)+1); | |
667 | strncpy(entcmd[cur_cmd].path, path, strlen(path)+1); | |
668 | entcmd[cur_cmd].rate = est; | |
669 | /* initialise other values */ | |
670 | entcmd[cur_cmd].sticky_badness = 1; | |
671 | ||
672 | cur_cmd++; | |
673 | ||
674 | /* If we've filled the array, reallocate it twice the size */ | |
675 | /* Do this now because even if this we're on the last command, | |
676 | we need another slot to mark the last entry */ | |
677 | if (cur_cmd == num_cmds) { | |
678 | num_cmds *= 2; | |
679 | entcmd = xrealloc(entcmd, num_cmds * sizeof(entropy_source_t)); | |
680 | } | |
681 | break; | |
682 | ||
683 | default: | |
684 | error("bad entropy command, %.100s line %d", cmdfilename, | |
685 | linenum); | |
686 | continue; | |
687 | } | |
688 | } | |
689 | ||
690 | /* zero the last entry */ | |
691 | memset(&entcmd[cur_cmd], '\0', sizeof(entropy_source_t)); | |
692 | /* trim to size */ | |
693 | entropy_sources = xrealloc(entcmd, (cur_cmd+1) * sizeof(entropy_source_t)); | |
694 | ||
695 | debug("loaded %d entropy commands from %.100s", cur_cmd, cmdfilename); | |
696 | ||
697 | return (cur_cmd >= MIN_ENTROPY_SOURCES); | |
698 | } | |
699 | ||
700 | ||
bfc9a610 | 701 | #endif /* defined(EGD_SOCKET) || defined(RANDOM_POOL) */ |
702 | ||
703 | #if defined(EGD_SOCKET) || defined(RANDOM_POOL) | |
b7a87eea | 704 | |
bfc9a610 | 705 | /* |
706 | * Seed OpenSSL's random number pool from Kernel random number generator | |
707 | * or EGD | |
708 | */ | |
709 | void | |
710 | seed_rng(void) | |
711 | { | |
712 | char buf[32]; | |
713 | ||
714 | debug("Seeding random number generator"); | |
715 | get_random_bytes(buf, sizeof(buf)); | |
716 | RAND_add(buf, sizeof(buf), sizeof(buf)); | |
717 | memset(buf, '\0', sizeof(buf)); | |
718 | } | |
b7a87eea | 719 | |
bfc9a610 | 720 | #else /* defined(EGD_SOCKET) || defined(RANDOM_POOL) */ |
b7a87eea | 721 | |
722 | /* | |
723 | * Write a keyfile at exit | |
724 | */ | |
725 | void | |
726 | prng_seed_cleanup(void *junk) | |
727 | { | |
728 | prng_write_seedfile(); | |
729 | } | |
730 | ||
bfc9a610 | 731 | /* |
b7a87eea | 732 | * Conditionally Seed OpenSSL's random number pool from |
733 | * syscalls and program output | |
bfc9a610 | 734 | */ |
735 | void | |
736 | seed_rng(void) | |
737 | { | |
d3083fbd | 738 | if (!prng_commands_loaded) { |
739 | if (!prng_read_commands(SSH_PRNG_COMMAND_FILE)) | |
740 | fatal("PRNG initialisation failed -- exiting."); | |
741 | prng_commands_loaded = 1; | |
742 | } | |
743 | ||
6c081128 | 744 | debug("Seeding random number generator."); |
745 | debug("OpenSSL random status is now %i\n", RAND_status()); | |
746 | debug("%i bytes from system calls", (int)stir_from_system()); | |
747 | debug("%i bytes from programs", (int)stir_from_programs()); | |
748 | debug("OpenSSL random status is now %i\n", RAND_status()); | |
b7a87eea | 749 | |
ad85db64 | 750 | if (!RAND_status()) |
751 | fatal("Couldn't initialise builtin random number generator -- exiting."); | |
752 | ||
b7a87eea | 753 | if (!prng_seed_loaded) |
754 | { | |
755 | prng_seed_loaded = 1; | |
756 | prng_seed_saved = 0; | |
757 | prng_read_seedfile(); | |
758 | fatal_add_cleanup(prng_seed_cleanup, NULL); | |
759 | atexit(prng_write_seedfile); | |
760 | } | |
bfc9a610 | 761 | } |
762 | #endif /* defined(EGD_SOCKET) || defined(RANDOM_POOL) */ |