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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. | |
bfc9a610 | 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 | ||
35484284 | 27 | #include <openssl/rand.h> |
28 | #include <openssl/sha.h> | |
bfc9a610 | 29 | |
819b676f | 30 | /* SunOS 4.4.4 needs this */ |
31 | #ifdef HAVE_FLOATINGPOINT_H | |
32 | # include <floatingpoint.h> | |
33 | #endif /* HAVE_FLOATINGPOINT_H */ | |
34 | ||
42f11eb2 | 35 | #include "ssh.h" |
36 | #include "xmalloc.h" | |
37 | #include "atomicio.h" | |
effa6591 | 38 | #include "pathnames.h" |
42f11eb2 | 39 | #include "log.h" |
40 | ||
bfc9a610 | 41 | RCSID("$Id$"); |
42 | ||
bfc9a610 | 43 | #ifndef offsetof |
44 | # define offsetof(type, member) ((size_t) &((type *)0)->member) | |
45 | #endif | |
48c99b2c | 46 | |
48c99b2c | 47 | /* Number of times to pass through command list gathering entropy */ |
48 | #define NUM_ENTROPY_RUNS 1 | |
49 | ||
50 | /* Scale entropy estimates back by this amount on subsequent runs */ | |
51 | #define SCALE_PER_RUN 10.0 | |
52 | ||
53 | /* Minimum number of commands to be considered valid */ | |
54 | #define MIN_ENTROPY_SOURCES 16 | |
55 | ||
56 | #define WHITESPACE " \t\n" | |
57 | ||
cbd7492e | 58 | #ifndef RUSAGE_SELF |
59 | # define RUSAGE_SELF 0 | |
60 | #endif | |
61 | #ifndef RUSAGE_CHILDREN | |
62 | # define RUSAGE_CHILDREN 0 | |
63 | #endif | |
64 | ||
48c99b2c | 65 | #if defined(EGD_SOCKET) || defined(RANDOM_POOL) |
66 | ||
67 | #ifdef EGD_SOCKET | |
bfc9a610 | 68 | /* Collect entropy from EGD */ |
be0b9bb7 | 69 | int get_random_bytes(unsigned char *buf, int len) |
bfc9a610 | 70 | { |
be0b9bb7 | 71 | int fd; |
72 | char msg[2]; | |
bfc9a610 | 73 | struct sockaddr_un addr; |
6a951840 | 74 | int addr_len, rval, errors; |
75 | struct sigaction nsa, osa; | |
bfc9a610 | 76 | |
be0b9bb7 | 77 | /* Sanity checks */ |
bfc9a610 | 78 | if (sizeof(EGD_SOCKET) > sizeof(addr.sun_path)) |
79 | fatal("Random pool path is too long"); | |
be0b9bb7 | 80 | if (len > 255) |
81 | fatal("Too many bytes to read from EGD"); | |
82 | ||
83 | memset(&addr, '\0', sizeof(addr)); | |
84 | addr.sun_family = AF_UNIX; | |
48c99b2c | 85 | strlcpy(addr.sun_path, EGD_SOCKET, sizeof(addr.sun_path)); |
bfc9a610 | 86 | addr_len = offsetof(struct sockaddr_un, sun_path) + sizeof(EGD_SOCKET); |
2b87da3b | 87 | |
6a951840 | 88 | memset(&nsa, 0, sizeof(nsa)); |
89 | nsa.sa_handler = SIG_IGN; | |
90 | (void) sigaction(SIGPIPE, &nsa, &osa); | |
91 | ||
92 | errors = rval = 0; | |
93 | reopen: | |
be0b9bb7 | 94 | fd = socket(AF_UNIX, SOCK_STREAM, 0); |
95 | if (fd == -1) { | |
96 | error("Couldn't create AF_UNIX socket: %s", strerror(errno)); | |
6a951840 | 97 | goto done; |
be0b9bb7 | 98 | } |
bfc9a610 | 99 | |
be0b9bb7 | 100 | if (connect(fd, (struct sockaddr*)&addr, addr_len) == -1) { |
2b87da3b | 101 | error("Couldn't connect to EGD socket \"%s\": %s", |
be0b9bb7 | 102 | addr.sun_path, strerror(errno)); |
6a951840 | 103 | goto done; |
be0b9bb7 | 104 | } |
bfc9a610 | 105 | |
be0b9bb7 | 106 | /* Send blocking read request to EGD */ |
107 | msg[0] = 0x02; | |
108 | msg[1] = len; | |
109 | ||
110 | if (atomicio(write, fd, msg, sizeof(msg)) != sizeof(msg)) { | |
6a951840 | 111 | if (errno == EPIPE && errors < 10) { |
112 | close(fd); | |
113 | errors++; | |
114 | goto reopen; | |
115 | } | |
2b87da3b | 116 | error("Couldn't write to EGD socket \"%s\": %s", |
be0b9bb7 | 117 | EGD_SOCKET, strerror(errno)); |
6a951840 | 118 | goto done; |
be0b9bb7 | 119 | } |
bfc9a610 | 120 | |
be0b9bb7 | 121 | if (atomicio(read, fd, buf, len) != len) { |
6a951840 | 122 | if (errno == EPIPE && errors < 10) { |
123 | close(fd); | |
124 | errors++; | |
125 | goto reopen; | |
126 | } | |
2b87da3b | 127 | error("Couldn't read from EGD socket \"%s\": %s", |
be0b9bb7 | 128 | EGD_SOCKET, strerror(errno)); |
6a951840 | 129 | goto done; |
be0b9bb7 | 130 | } |
2b87da3b | 131 | |
6a951840 | 132 | rval = 1; |
133 | done: | |
134 | (void) sigaction(SIGPIPE, &osa, NULL); | |
135 | if (fd != -1) | |
136 | close(fd); | |
137 | return(rval); | |
bfc9a610 | 138 | } |
139 | #else /* !EGD_SOCKET */ | |
140 | #ifdef RANDOM_POOL | |
141 | /* Collect entropy from /dev/urandom or pipe */ | |
be0b9bb7 | 142 | int get_random_bytes(unsigned char *buf, int len) |
bfc9a610 | 143 | { |
be0b9bb7 | 144 | int random_pool; |
bfc9a610 | 145 | |
be0b9bb7 | 146 | random_pool = open(RANDOM_POOL, O_RDONLY); |
bfc9a610 | 147 | if (random_pool == -1) { |
2b87da3b | 148 | error("Couldn't open random pool \"%s\": %s", |
be0b9bb7 | 149 | RANDOM_POOL, strerror(errno)); |
150 | return(0); | |
bfc9a610 | 151 | } |
2b87da3b | 152 | |
be0b9bb7 | 153 | if (atomicio(read, random_pool, buf, len) != len) { |
2b87da3b | 154 | error("Couldn't read from random pool \"%s\": %s", |
be0b9bb7 | 155 | RANDOM_POOL, strerror(errno)); |
156 | close(random_pool); | |
157 | return(0); | |
158 | } | |
2b87da3b | 159 | |
be0b9bb7 | 160 | close(random_pool); |
2b87da3b | 161 | |
be0b9bb7 | 162 | return(1); |
bfc9a610 | 163 | } |
164 | #endif /* RANDOM_POOL */ | |
165 | #endif /* EGD_SOCKET */ | |
166 | ||
48c99b2c | 167 | /* |
168 | * Seed OpenSSL's random number pool from Kernel random number generator | |
169 | * or EGD | |
170 | */ | |
171 | void | |
172 | seed_rng(void) | |
173 | { | |
174 | char buf[32]; | |
2b87da3b | 175 | |
48c99b2c | 176 | debug("Seeding random number generator"); |
be0b9bb7 | 177 | |
b5b3f75d | 178 | if (!get_random_bytes(buf, sizeof(buf))) { |
179 | if (!RAND_status()) | |
180 | fatal("Entropy collection failed and entropy exhausted"); | |
181 | } else { | |
182 | RAND_add(buf, sizeof(buf), sizeof(buf)); | |
183 | } | |
2b87da3b | 184 | |
48c99b2c | 185 | memset(buf, '\0', sizeof(buf)); |
186 | } | |
187 | ||
264dce47 | 188 | /* No-op */ |
189 | void init_rng(void) {} | |
190 | ||
48c99b2c | 191 | #else /* defined(EGD_SOCKET) || defined(RANDOM_POOL) */ |
192 | ||
2b87da3b | 193 | /* |
bfc9a610 | 194 | * FIXME: proper entropy estimations. All current values are guesses |
b7a87eea | 195 | * FIXME: (ATL) do estimates at compile time? |
bfc9a610 | 196 | * FIXME: More entropy sources |
197 | */ | |
198 | ||
b7a87eea | 199 | /* slow command timeouts (all in milliseconds) */ |
200 | /* static int entropy_timeout_default = ENTROPY_TIMEOUT_MSEC; */ | |
201 | static int entropy_timeout_current = ENTROPY_TIMEOUT_MSEC; | |
202 | ||
d3083fbd | 203 | static int prng_seed_saved = 0; |
264dce47 | 204 | static int prng_initialised = 0; |
205 | uid_t original_uid; | |
bfc9a610 | 206 | |
207 | typedef struct | |
208 | { | |
209 | /* Proportion of data that is entropy */ | |
210 | double rate; | |
b7a87eea | 211 | /* Counter goes positive if this command times out */ |
212 | unsigned int badness; | |
213 | /* Increases by factor of two each timeout */ | |
214 | unsigned int sticky_badness; | |
bfc9a610 | 215 | /* Path to executable */ |
d3083fbd | 216 | char *path; |
bfc9a610 | 217 | /* argv to pass to executable */ |
d3083fbd | 218 | char *args[5]; |
ad85db64 | 219 | /* full command string (debug) */ |
220 | char *cmdstring; | |
bfc9a610 | 221 | } entropy_source_t; |
222 | ||
b7a87eea | 223 | double stir_from_system(void); |
224 | double stir_from_programs(void); | |
225 | double stir_gettimeofday(double entropy_estimate); | |
226 | double stir_clock(double entropy_estimate); | |
227 | double stir_rusage(int who, double entropy_estimate); | |
228 | double hash_output_from_command(entropy_source_t *src, char *hash); | |
229 | ||
d3083fbd | 230 | /* this is initialised from a file, by prng_read_commands() */ |
231 | entropy_source_t *entropy_sources = NULL; | |
bfc9a610 | 232 | |
2b87da3b | 233 | double |
bfc9a610 | 234 | stir_from_system(void) |
235 | { | |
236 | double total_entropy_estimate; | |
237 | long int i; | |
2b87da3b | 238 | |
bfc9a610 | 239 | total_entropy_estimate = 0; |
2b87da3b | 240 | |
bfc9a610 | 241 | i = getpid(); |
cbd7492e | 242 | RAND_add(&i, sizeof(i), 0.5); |
bfc9a610 | 243 | total_entropy_estimate += 0.1; |
2b87da3b | 244 | |
bfc9a610 | 245 | i = getppid(); |
cbd7492e | 246 | RAND_add(&i, sizeof(i), 0.5); |
bfc9a610 | 247 | total_entropy_estimate += 0.1; |
248 | ||
249 | i = getuid(); | |
250 | RAND_add(&i, sizeof(i), 0.0); | |
251 | i = getgid(); | |
252 | RAND_add(&i, sizeof(i), 0.0); | |
253 | ||
254 | total_entropy_estimate += stir_gettimeofday(1.0); | |
cbd7492e | 255 | total_entropy_estimate += stir_clock(0.5); |
bfc9a610 | 256 | total_entropy_estimate += stir_rusage(RUSAGE_SELF, 2.0); |
257 | ||
258 | return(total_entropy_estimate); | |
259 | } | |
260 | ||
2b87da3b | 261 | double |
bfc9a610 | 262 | stir_from_programs(void) |
263 | { | |
264 | int i; | |
265 | int c; | |
266 | double entropy_estimate; | |
267 | double total_entropy_estimate; | |
268 | char hash[SHA_DIGEST_LENGTH]; | |
269 | ||
bfc9a610 | 270 | total_entropy_estimate = 0; |
48c99b2c | 271 | for(i = 0; i < NUM_ENTROPY_RUNS; i++) { |
bfc9a610 | 272 | c = 0; |
273 | while (entropy_sources[c].path != NULL) { | |
bfc9a610 | 274 | |
b7a87eea | 275 | if (!entropy_sources[c].badness) { |
276 | /* Hash output from command */ | |
277 | entropy_estimate = hash_output_from_command(&entropy_sources[c], hash); | |
278 | ||
279 | /* Scale back entropy estimate according to command's rate */ | |
280 | entropy_estimate *= entropy_sources[c].rate; | |
2b87da3b | 281 | |
b7a87eea | 282 | /* Upper bound of entropy estimate is SHA_DIGEST_LENGTH */ |
283 | if (entropy_estimate > SHA_DIGEST_LENGTH) | |
284 | entropy_estimate = SHA_DIGEST_LENGTH; | |
bfc9a610 | 285 | |
2b87da3b | 286 | /* Scale back estimates for subsequent passes through list */ |
48c99b2c | 287 | entropy_estimate /= SCALE_PER_RUN * (i + 1.0); |
2b87da3b | 288 | |
b7a87eea | 289 | /* Stir it in */ |
290 | RAND_add(hash, sizeof(hash), entropy_estimate); | |
bfc9a610 | 291 | |
2b87da3b | 292 | debug3("Got %0.2f bytes of entropy from '%s'", entropy_estimate, |
ad85db64 | 293 | entropy_sources[c].cmdstring); |
bfc9a610 | 294 | |
b7a87eea | 295 | total_entropy_estimate += entropy_estimate; |
bfc9a610 | 296 | |
297 | /* Execution times should be a little unpredictable */ | |
b7a87eea | 298 | total_entropy_estimate += stir_gettimeofday(0.05); |
299 | total_entropy_estimate += stir_clock(0.05); | |
300 | total_entropy_estimate += stir_rusage(RUSAGE_SELF, 0.1); | |
301 | total_entropy_estimate += stir_rusage(RUSAGE_CHILDREN, 0.1); | |
302 | } else { | |
22d89d24 | 303 | debug2("Command '%s' disabled (badness %d)", |
ad85db64 | 304 | entropy_sources[c].cmdstring, entropy_sources[c].badness); |
b7a87eea | 305 | |
306 | if (entropy_sources[c].badness > 0) | |
307 | entropy_sources[c].badness--; | |
308 | } | |
309 | ||
bfc9a610 | 310 | c++; |
311 | } | |
312 | } | |
2b87da3b | 313 | |
bfc9a610 | 314 | return(total_entropy_estimate); |
315 | } | |
316 | ||
317 | double | |
318 | stir_gettimeofday(double entropy_estimate) | |
319 | { | |
320 | struct timeval tv; | |
2b87da3b | 321 | |
bfc9a610 | 322 | if (gettimeofday(&tv, NULL) == -1) |
323 | fatal("Couldn't gettimeofday: %s", strerror(errno)); | |
324 | ||
325 | RAND_add(&tv, sizeof(tv), entropy_estimate); | |
2b87da3b | 326 | |
bfc9a610 | 327 | return(entropy_estimate); |
328 | } | |
329 | ||
330 | double | |
331 | stir_clock(double entropy_estimate) | |
332 | { | |
333 | #ifdef HAVE_CLOCK | |
334 | clock_t c; | |
2b87da3b | 335 | |
bfc9a610 | 336 | c = clock(); |
337 | RAND_add(&c, sizeof(c), entropy_estimate); | |
2b87da3b | 338 | |
bfc9a610 | 339 | return(entropy_estimate); |
340 | #else /* _HAVE_CLOCK */ | |
341 | return(0); | |
342 | #endif /* _HAVE_CLOCK */ | |
343 | } | |
344 | ||
345 | double | |
346 | stir_rusage(int who, double entropy_estimate) | |
347 | { | |
348 | #ifdef HAVE_GETRUSAGE | |
349 | struct rusage ru; | |
2b87da3b | 350 | |
b7a87eea | 351 | if (getrusage(who, &ru) == -1) |
cbd7492e | 352 | return(0); |
bfc9a610 | 353 | |
cbd7492e | 354 | RAND_add(&ru, sizeof(ru), entropy_estimate); |
bfc9a610 | 355 | |
356 | return(entropy_estimate); | |
357 | #else /* _HAVE_GETRUSAGE */ | |
358 | return(0); | |
359 | #endif /* _HAVE_GETRUSAGE */ | |
360 | } | |
361 | ||
ad85db64 | 362 | |
363 | static | |
364 | int | |
365 | _get_timeval_msec_difference(struct timeval *t1, struct timeval *t2) { | |
366 | int secdiff, usecdiff; | |
367 | ||
368 | secdiff = t2->tv_sec - t1->tv_sec; | |
369 | usecdiff = (secdiff*1000000) + (t2->tv_usec - t1->tv_usec); | |
370 | return (int)(usecdiff / 1000); | |
371 | } | |
372 | ||
bfc9a610 | 373 | double |
b7a87eea | 374 | hash_output_from_command(entropy_source_t *src, char *hash) |
bfc9a610 | 375 | { |
376 | static int devnull = -1; | |
377 | int p[2]; | |
b7a87eea | 378 | fd_set rdset; |
379 | int cmd_eof = 0, error_abort = 0; | |
ad85db64 | 380 | struct timeval tv_start, tv_current; |
381 | int msec_elapsed = 0; | |
bfc9a610 | 382 | pid_t pid; |
383 | int status; | |
ad85db64 | 384 | char buf[16384]; |
bfc9a610 | 385 | int bytes_read; |
386 | int total_bytes_read; | |
387 | SHA_CTX sha; | |
2b87da3b | 388 | |
22d89d24 | 389 | debug3("Reading output from \'%s\'", src->cmdstring); |
390 | ||
bfc9a610 | 391 | if (devnull == -1) { |
392 | devnull = open("/dev/null", O_RDWR); | |
393 | if (devnull == -1) | |
394 | fatal("Couldn't open /dev/null: %s", strerror(errno)); | |
395 | } | |
2b87da3b | 396 | |
bfc9a610 | 397 | if (pipe(p) == -1) |
398 | fatal("Couldn't open pipe: %s", strerror(errno)); | |
399 | ||
ad85db64 | 400 | (void)gettimeofday(&tv_start, NULL); /* record start time */ |
401 | ||
bfc9a610 | 402 | switch (pid = fork()) { |
403 | case -1: /* Error */ | |
404 | close(p[0]); | |
405 | close(p[1]); | |
406 | fatal("Couldn't fork: %s", strerror(errno)); | |
407 | /* NOTREACHED */ | |
408 | case 0: /* Child */ | |
b7a87eea | 409 | dup2(devnull, STDIN_FILENO); |
410 | dup2(p[1], STDOUT_FILENO); | |
411 | dup2(p[1], STDERR_FILENO); | |
bfc9a610 | 412 | close(p[0]); |
413 | close(p[1]); | |
414 | close(devnull); | |
415 | ||
264dce47 | 416 | setuid(original_uid); |
b7a87eea | 417 | execv(src->path, (char**)(src->args)); |
ad85db64 | 418 | debug("(child) Couldn't exec '%s': %s", src->cmdstring, |
419 | strerror(errno)); | |
bfc9a610 | 420 | _exit(-1); |
421 | default: /* Parent */ | |
422 | break; | |
423 | } | |
424 | ||
425 | RAND_add(&pid, sizeof(&pid), 0.0); | |
426 | ||
427 | close(p[1]); | |
428 | ||
429 | /* Hash output from child */ | |
430 | SHA1_Init(&sha); | |
431 | total_bytes_read = 0; | |
b7a87eea | 432 | |
433 | while (!error_abort && !cmd_eof) { | |
434 | int ret; | |
435 | struct timeval tv; | |
ad85db64 | 436 | int msec_remaining; |
437 | ||
438 | (void) gettimeofday(&tv_current, 0); | |
48c99b2c | 439 | msec_elapsed = _get_timeval_msec_difference(&tv_start, &tv_current); |
ad85db64 | 440 | if (msec_elapsed >= entropy_timeout_current) { |
441 | error_abort=1; | |
442 | continue; | |
443 | } | |
444 | msec_remaining = entropy_timeout_current - msec_elapsed; | |
b7a87eea | 445 | |
446 | FD_ZERO(&rdset); | |
447 | FD_SET(p[0], &rdset); | |
ad85db64 | 448 | tv.tv_sec = msec_remaining / 1000; |
449 | tv.tv_usec = (msec_remaining % 1000) * 1000; | |
b7a87eea | 450 | |
451 | ret = select(p[0]+1, &rdset, NULL, NULL, &tv); | |
ad85db64 | 452 | |
264dce47 | 453 | RAND_add(&tv, sizeof(tv), 0.0); |
454 | ||
b7a87eea | 455 | switch (ret) { |
456 | case 0: | |
457 | /* timer expired */ | |
458 | error_abort = 1; | |
459 | break; | |
b7a87eea | 460 | case 1: |
461 | /* command input */ | |
462 | bytes_read = read(p[0], buf, sizeof(buf)); | |
264dce47 | 463 | RAND_add(&bytes_read, sizeof(&bytes_read), 0.0); |
b7a87eea | 464 | if (bytes_read == -1) { |
465 | error_abort = 1; | |
466 | break; | |
264dce47 | 467 | } else if (bytes_read) { |
ad85db64 | 468 | SHA1_Update(&sha, buf, bytes_read); |
469 | total_bytes_read += bytes_read; | |
264dce47 | 470 | } else { |
ad85db64 | 471 | cmd_eof = 1; |
264dce47 | 472 | } |
b7a87eea | 473 | break; |
b7a87eea | 474 | case -1: |
475 | default: | |
264dce47 | 476 | /* error */ |
ad85db64 | 477 | debug("Command '%s': select() failed: %s", src->cmdstring, |
478 | strerror(errno)); | |
b7a87eea | 479 | error_abort = 1; |
480 | break; | |
264dce47 | 481 | } |
482 | } | |
b7a87eea | 483 | |
bfc9a610 | 484 | SHA1_Final(hash, &sha); |
485 | ||
486 | close(p[0]); | |
ad85db64 | 487 | |
22d89d24 | 488 | debug3("Time elapsed: %d msec", msec_elapsed); |
2b87da3b | 489 | |
bfc9a610 | 490 | if (waitpid(pid, &status, 0) == -1) { |
22d89d24 | 491 | error("Couldn't wait for child '%s' completion: %s", src->cmdstring, |
ad85db64 | 492 | strerror(errno)); |
b7a87eea | 493 | return(0.0); |
bfc9a610 | 494 | } |
495 | ||
496 | RAND_add(&status, sizeof(&status), 0.0); | |
497 | ||
b7a87eea | 498 | if (error_abort) { |
499 | /* closing p[0] on timeout causes the entropy command to | |
500 | * SIGPIPE. Take whatever output we got, and mark this command | |
501 | * as slow */ | |
22d89d24 | 502 | debug2("Command '%s' timed out", src->cmdstring); |
b7a87eea | 503 | src->sticky_badness *= 2; |
504 | src->badness = src->sticky_badness; | |
bfc9a610 | 505 | return(total_bytes_read); |
b7a87eea | 506 | } |
507 | ||
508 | if (WIFEXITED(status)) { | |
509 | if (WEXITSTATUS(status)==0) { | |
510 | return(total_bytes_read); | |
511 | } else { | |
2b87da3b | 512 | debug2("Command '%s' exit status was %d", src->cmdstring, |
48c99b2c | 513 | WEXITSTATUS(status)); |
b7a87eea | 514 | src->badness = src->sticky_badness = 128; |
515 | return (0.0); | |
516 | } | |
517 | } else if (WIFSIGNALED(status)) { | |
2b87da3b | 518 | debug2("Command '%s' returned on uncaught signal %d !", src->cmdstring, |
48c99b2c | 519 | status); |
b7a87eea | 520 | src->badness = src->sticky_badness = 128; |
521 | return(0.0); | |
522 | } else | |
523 | return(0.0); | |
524 | } | |
525 | ||
526 | /* | |
527 | * prng seedfile functions | |
528 | */ | |
529 | int | |
530 | prng_check_seedfile(char *filename) { | |
531 | ||
532 | struct stat st; | |
533 | ||
534 | /* FIXME raceable: eg replace seed between this stat and subsequent open */ | |
535 | /* Not such a problem because we don't trust the seed file anyway */ | |
536 | if (lstat(filename, &st) == -1) { | |
5b2d4b75 | 537 | /* Give up on hard errors */ |
b7a87eea | 538 | if (errno != ENOENT) |
2b87da3b | 539 | debug("WARNING: Couldn't stat random seed file \"%s\": %s", |
5b2d4b75 | 540 | filename, strerror(errno)); |
b7a87eea | 541 | |
542 | return(0); | |
543 | } | |
544 | ||
545 | /* regular file? */ | |
546 | if (!S_ISREG(st.st_mode)) | |
547 | fatal("PRNG seedfile %.100s is not a regular file", filename); | |
548 | ||
549 | /* mode 0600, owned by root or the current user? */ | |
5b2d4b75 | 550 | if (((st.st_mode & 0177) != 0) || !(st.st_uid == original_uid)) { |
551 | debug("WARNING: PRNG seedfile %.100s must be mode 0600, owned by uid %d", | |
b7a87eea | 552 | filename, getuid()); |
5b2d4b75 | 553 | return(0); |
554 | } | |
2b87da3b | 555 | |
b7a87eea | 556 | return(1); |
557 | } | |
558 | ||
559 | void | |
560 | prng_write_seedfile(void) { | |
561 | int fd; | |
562 | char seed[1024]; | |
563 | char filename[1024]; | |
564 | struct passwd *pw; | |
565 | ||
566 | /* Don't bother if we have already saved a seed */ | |
567 | if (prng_seed_saved) | |
568 | return; | |
2b87da3b | 569 | |
264dce47 | 570 | setuid(original_uid); |
2b87da3b | 571 | |
52bcc044 | 572 | prng_seed_saved = 1; |
2b87da3b | 573 | |
264dce47 | 574 | pw = getpwuid(original_uid); |
b7a87eea | 575 | if (pw == NULL) |
2b87da3b | 576 | fatal("Couldn't get password entry for current user (%i): %s", |
264dce47 | 577 | original_uid, strerror(errno)); |
2b87da3b | 578 | |
b7a87eea | 579 | /* Try to ensure that the parent directory is there */ |
2b87da3b | 580 | snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir, |
effa6591 | 581 | _PATH_SSH_USER_DIR); |
b7a87eea | 582 | mkdir(filename, 0700); |
583 | ||
2b87da3b | 584 | snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir, |
b7a87eea | 585 | SSH_PRNG_SEED_FILE); |
586 | ||
587 | debug("writing PRNG seed to file %.100s", filename); | |
588 | ||
589 | RAND_bytes(seed, sizeof(seed)); | |
590 | ||
591 | /* Don't care if the seed doesn't exist */ | |
592 | prng_check_seedfile(filename); | |
2b87da3b | 593 | |
5b2d4b75 | 594 | if ((fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0600)) == -1) { |
2b87da3b | 595 | debug("WARNING: couldn't access PRNG seedfile %.100s (%.100s)", |
5b2d4b75 | 596 | filename, strerror(errno)); |
2b87da3b | 597 | } else { |
5b2d4b75 | 598 | if (atomicio(write, fd, &seed, sizeof(seed)) != sizeof(seed)) |
2b87da3b | 599 | fatal("problem writing PRNG seedfile %.100s (%.100s)", filename, |
5b2d4b75 | 600 | strerror(errno)); |
b7a87eea | 601 | |
5b2d4b75 | 602 | close(fd); |
603 | } | |
b7a87eea | 604 | } |
605 | ||
606 | void | |
607 | prng_read_seedfile(void) { | |
608 | int fd; | |
609 | char seed[1024]; | |
610 | char filename[1024]; | |
611 | struct passwd *pw; | |
2b87da3b | 612 | |
264dce47 | 613 | pw = getpwuid(original_uid); |
b7a87eea | 614 | if (pw == NULL) |
2b87da3b | 615 | fatal("Couldn't get password entry for current user (%i): %s", |
264dce47 | 616 | original_uid, strerror(errno)); |
2b87da3b | 617 | |
618 | snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir, | |
b7a87eea | 619 | SSH_PRNG_SEED_FILE); |
620 | ||
621 | debug("loading PRNG seed from file %.100s", filename); | |
622 | ||
623 | if (!prng_check_seedfile(filename)) { | |
52ce34a2 | 624 | verbose("Random seed file not found or not valid, ignoring."); |
b7a87eea | 625 | return; |
626 | } | |
627 | ||
628 | /* open the file and read in the seed */ | |
629 | fd = open(filename, O_RDONLY); | |
630 | if (fd == -1) | |
2b87da3b | 631 | fatal("could not open PRNG seedfile %.100s (%.100s)", filename, |
b7a87eea | 632 | strerror(errno)); |
633 | ||
634 | if (atomicio(read, fd, &seed, sizeof(seed)) != sizeof(seed)) { | |
635 | verbose("invalid or short read from PRNG seedfile %.100s - ignoring", | |
636 | filename); | |
637 | memset(seed, '\0', sizeof(seed)); | |
638 | } | |
639 | close(fd); | |
640 | ||
641 | /* stir in the seed, with estimated entropy zero */ | |
642 | RAND_add(&seed, sizeof(seed), 0.0); | |
bfc9a610 | 643 | } |
b7a87eea | 644 | |
d3083fbd | 645 | |
646 | /* | |
647 | * entropy command initialisation functions | |
648 | */ | |
d3083fbd | 649 | int |
650 | prng_read_commands(char *cmdfilename) | |
651 | { | |
652 | FILE *f; | |
d3083fbd | 653 | char *cp; |
48c99b2c | 654 | char line[1024]; |
655 | char cmd[1024]; | |
656 | char path[256]; | |
d3083fbd | 657 | int linenum; |
d3083fbd | 658 | int num_cmds = 64; |
659 | int cur_cmd = 0; | |
48c99b2c | 660 | double est; |
661 | entropy_source_t *entcmd; | |
d3083fbd | 662 | |
663 | f = fopen(cmdfilename, "r"); | |
664 | if (!f) { | |
665 | fatal("couldn't read entropy commands file %.100s: %.100s", | |
666 | cmdfilename, strerror(errno)); | |
667 | } | |
668 | ||
d3083fbd | 669 | entcmd = (entropy_source_t *)xmalloc(num_cmds * sizeof(entropy_source_t)); |
670 | memset(entcmd, '\0', num_cmds * sizeof(entropy_source_t)); | |
671 | ||
48c99b2c | 672 | /* Read in file */ |
673 | linenum = 0; | |
d3083fbd | 674 | while (fgets(line, sizeof(line), f)) { |
48c99b2c | 675 | int arg; |
676 | char *argv; | |
677 | ||
d3083fbd | 678 | linenum++; |
679 | ||
680 | /* skip leading whitespace, test for blank line or comment */ | |
681 | cp = line + strspn(line, WHITESPACE); | |
682 | if ((*cp == 0) || (*cp == '#')) | |
683 | continue; /* done with this line */ | |
684 | ||
48c99b2c | 685 | /* First non-whitespace char should be double quote delimiting */ |
686 | /* commandline */ | |
687 | if (*cp != '"') { | |
688 | error("bad entropy command, %.100s line %d", cmdfilename, | |
689 | linenum); | |
690 | continue; | |
2b87da3b | 691 | } |
d3083fbd | 692 | |
48c99b2c | 693 | /* first token, command args (incl. argv[0]) in double quotes */ |
694 | cp = strtok(cp, "\""); | |
695 | if (cp == NULL) { | |
696 | error("missing or bad command string, %.100s line %d -- ignored", | |
697 | cmdfilename, linenum); | |
698 | continue; | |
699 | } | |
700 | strlcpy(cmd, cp, sizeof(cmd)); | |
2b87da3b | 701 | |
48c99b2c | 702 | /* second token, full command path */ |
703 | if ((cp = strtok(NULL, WHITESPACE)) == NULL) { | |
704 | error("missing command path, %.100s line %d -- ignored", | |
705 | cmdfilename, linenum); | |
706 | continue; | |
707 | } | |
d3083fbd | 708 | |
48c99b2c | 709 | /* did configure mark this as dead? */ |
710 | if (strncmp("undef", cp, 5) == 0) | |
711 | continue; | |
d3083fbd | 712 | |
2b87da3b | 713 | strlcpy(path, cp, sizeof(path)); |
48c99b2c | 714 | |
715 | /* third token, entropy rate estimate for this command */ | |
716 | if ((cp = strtok(NULL, WHITESPACE)) == NULL) { | |
717 | error("missing entropy estimate, %.100s line %d -- ignored", | |
718 | cmdfilename, linenum); | |
719 | continue; | |
720 | } | |
721 | est = strtod(cp, &argv); | |
722 | ||
723 | /* end of line */ | |
724 | if ((cp = strtok(NULL, WHITESPACE)) != NULL) { | |
2b87da3b | 725 | error("garbage at end of line %d in %.100s -- ignored", linenum, |
48c99b2c | 726 | cmdfilename); |
d3083fbd | 727 | continue; |
728 | } | |
48c99b2c | 729 | |
730 | /* save the command for debug messages */ | |
731 | entcmd[cur_cmd].cmdstring = xstrdup(cmd); | |
2b87da3b | 732 | |
48c99b2c | 733 | /* split the command args */ |
734 | cp = strtok(cmd, WHITESPACE); | |
735 | arg = 0; | |
736 | argv = NULL; | |
737 | do { | |
738 | char *s = (char*)xmalloc(strlen(cp) + 1); | |
739 | strncpy(s, cp, strlen(cp) + 1); | |
740 | entcmd[cur_cmd].args[arg] = s; | |
741 | arg++; | |
742 | } while ((arg < 5) && (cp = strtok(NULL, WHITESPACE))); | |
2b87da3b | 743 | |
48c99b2c | 744 | if (strtok(NULL, WHITESPACE)) |
745 | error("ignored extra command elements (max 5), %.100s line %d", | |
746 | cmdfilename, linenum); | |
747 | ||
748 | /* Copy the command path and rate estimate */ | |
749 | entcmd[cur_cmd].path = xstrdup(path); | |
750 | entcmd[cur_cmd].rate = est; | |
751 | ||
752 | /* Initialise other values */ | |
753 | entcmd[cur_cmd].sticky_badness = 1; | |
754 | ||
755 | cur_cmd++; | |
756 | ||
757 | /* If we've filled the array, reallocate it twice the size */ | |
758 | /* Do this now because even if this we're on the last command, | |
759 | we need another slot to mark the last entry */ | |
760 | if (cur_cmd == num_cmds) { | |
761 | num_cmds *= 2; | |
762 | entcmd = xrealloc(entcmd, num_cmds * sizeof(entropy_source_t)); | |
763 | } | |
d3083fbd | 764 | } |
765 | ||
766 | /* zero the last entry */ | |
767 | memset(&entcmd[cur_cmd], '\0', sizeof(entropy_source_t)); | |
48c99b2c | 768 | |
d3083fbd | 769 | /* trim to size */ |
770 | entropy_sources = xrealloc(entcmd, (cur_cmd+1) * sizeof(entropy_source_t)); | |
771 | ||
264dce47 | 772 | debug("Loaded %d entropy commands from %.100s", cur_cmd, cmdfilename); |
d3083fbd | 773 | |
774 | return (cur_cmd >= MIN_ENTROPY_SOURCES); | |
775 | } | |
776 | ||
b7a87eea | 777 | /* |
778 | * Write a keyfile at exit | |
2b87da3b | 779 | */ |
b7a87eea | 780 | void |
781 | prng_seed_cleanup(void *junk) | |
782 | { | |
783 | prng_write_seedfile(); | |
784 | } | |
785 | ||
bfc9a610 | 786 | /* |
b7a87eea | 787 | * Conditionally Seed OpenSSL's random number pool from |
788 | * syscalls and program output | |
bfc9a610 | 789 | */ |
790 | void | |
791 | seed_rng(void) | |
792 | { | |
a64009ad | 793 | void *old_sigchld_handler; |
d3083fbd | 794 | |
264dce47 | 795 | if (!prng_initialised) |
796 | fatal("RNG not initialised"); | |
2b87da3b | 797 | |
a64009ad | 798 | /* Make sure some other sigchld handler doesn't reap our entropy */ |
799 | /* commands */ | |
800 | old_sigchld_handler = signal(SIGCHLD, SIG_DFL); | |
801 | ||
264dce47 | 802 | debug("Seeded RNG with %i bytes from programs", (int)stir_from_programs()); |
803 | debug("Seeded RNG with %i bytes from system calls", (int)stir_from_system()); | |
804 | ||
805 | if (!RAND_status()) | |
806 | fatal("Not enough entropy in RNG"); | |
b7a87eea | 807 | |
a64009ad | 808 | signal(SIGCHLD, old_sigchld_handler); |
809 | ||
ad85db64 | 810 | if (!RAND_status()) |
811 | fatal("Couldn't initialise builtin random number generator -- exiting."); | |
264dce47 | 812 | } |
ad85db64 | 813 | |
2b87da3b | 814 | void init_rng(void) |
264dce47 | 815 | { |
e879a080 | 816 | int original_euid; |
2b87da3b | 817 | |
264dce47 | 818 | original_uid = getuid(); |
e879a080 | 819 | original_euid = geteuid(); |
264dce47 | 820 | |
821 | /* Read in collection commands */ | |
822 | if (!prng_read_commands(SSH_PRNG_COMMAND_FILE)) | |
823 | fatal("PRNG initialisation failed -- exiting."); | |
824 | ||
825 | /* Set ourselves up to save a seed upon exit */ | |
2b87da3b | 826 | prng_seed_saved = 0; |
e879a080 | 827 | |
828 | /* Give up privs while reading seed file */ | |
829 | if ((original_uid != original_euid) && (seteuid(original_uid) == -1)) | |
830 | fatal("Couldn't give up privileges"); | |
2b87da3b | 831 | |
264dce47 | 832 | prng_read_seedfile(); |
e879a080 | 833 | |
834 | if ((original_uid != original_euid) && (seteuid(original_euid) == -1)) | |
835 | fatal("Couldn't restore privileges"); | |
836 | ||
264dce47 | 837 | fatal_add_cleanup(prng_seed_cleanup, NULL); |
838 | atexit(prng_write_seedfile); | |
839 | ||
840 | prng_initialised = 1; | |
bfc9a610 | 841 | } |
264dce47 | 842 | |
bfc9a610 | 843 | #endif /* defined(EGD_SOCKET) || defined(RANDOM_POOL) */ |