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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> | |
c7c72446 | 29 | #include <openssl/crypto.h> |
bfc9a610 | 30 | |
819b676f | 31 | /* SunOS 4.4.4 needs this */ |
32 | #ifdef HAVE_FLOATINGPOINT_H | |
33 | # include <floatingpoint.h> | |
34 | #endif /* HAVE_FLOATINGPOINT_H */ | |
35 | ||
42f11eb2 | 36 | #include "ssh.h" |
e1a023df | 37 | #include "misc.h" |
42f11eb2 | 38 | #include "xmalloc.h" |
39 | #include "atomicio.h" | |
effa6591 | 40 | #include "pathnames.h" |
42f11eb2 | 41 | #include "log.h" |
42 | ||
bfc9a610 | 43 | RCSID("$Id$"); |
44 | ||
bfc9a610 | 45 | #ifndef offsetof |
46 | # define offsetof(type, member) ((size_t) &((type *)0)->member) | |
47 | #endif | |
48c99b2c | 48 | |
48c99b2c | 49 | /* Number of times to pass through command list gathering entropy */ |
50 | #define NUM_ENTROPY_RUNS 1 | |
51 | ||
52 | /* Scale entropy estimates back by this amount on subsequent runs */ | |
53 | #define SCALE_PER_RUN 10.0 | |
54 | ||
55 | /* Minimum number of commands to be considered valid */ | |
56 | #define MIN_ENTROPY_SOURCES 16 | |
57 | ||
58 | #define WHITESPACE " \t\n" | |
59 | ||
cbd7492e | 60 | #ifndef RUSAGE_SELF |
61 | # define RUSAGE_SELF 0 | |
62 | #endif | |
63 | #ifndef RUSAGE_CHILDREN | |
64 | # define RUSAGE_CHILDREN 0 | |
65 | #endif | |
66 | ||
86b416a7 | 67 | #if defined(_POSIX_SAVED_IDS) && !defined(BROKEN_SAVED_UIDS) |
68 | # define SAVED_IDS_WORK_WITH_SETEUID | |
69 | #endif | |
70 | ||
c7c72446 | 71 | void check_openssl_version(void) |
72 | { | |
73 | if (SSLeay() != OPENSSL_VERSION_NUMBER) | |
74 | fatal("OpenSSL version mismatch. Built against %x, you " | |
75 | "have %x", OPENSSL_VERSION_NUMBER, SSLeay()); | |
76 | } | |
77 | ||
78 | ||
48c99b2c | 79 | #if defined(EGD_SOCKET) || defined(RANDOM_POOL) |
80 | ||
81 | #ifdef EGD_SOCKET | |
bfc9a610 | 82 | /* Collect entropy from EGD */ |
be0b9bb7 | 83 | int get_random_bytes(unsigned char *buf, int len) |
bfc9a610 | 84 | { |
be0b9bb7 | 85 | int fd; |
86 | char msg[2]; | |
bfc9a610 | 87 | struct sockaddr_un addr; |
6a951840 | 88 | int addr_len, rval, errors; |
e1a023df | 89 | mysig_t old_sigpipe; |
bfc9a610 | 90 | |
be0b9bb7 | 91 | /* Sanity checks */ |
bfc9a610 | 92 | if (sizeof(EGD_SOCKET) > sizeof(addr.sun_path)) |
93 | fatal("Random pool path is too long"); | |
be0b9bb7 | 94 | if (len > 255) |
95 | fatal("Too many bytes to read from EGD"); | |
96 | ||
97 | memset(&addr, '\0', sizeof(addr)); | |
98 | addr.sun_family = AF_UNIX; | |
48c99b2c | 99 | strlcpy(addr.sun_path, EGD_SOCKET, sizeof(addr.sun_path)); |
bfc9a610 | 100 | addr_len = offsetof(struct sockaddr_un, sun_path) + sizeof(EGD_SOCKET); |
2b87da3b | 101 | |
e1a023df | 102 | old_sigpipe = mysignal(SIGPIPE, SIG_IGN); |
6a951840 | 103 | |
104 | errors = rval = 0; | |
105 | reopen: | |
be0b9bb7 | 106 | fd = socket(AF_UNIX, SOCK_STREAM, 0); |
107 | if (fd == -1) { | |
108 | error("Couldn't create AF_UNIX socket: %s", strerror(errno)); | |
6a951840 | 109 | goto done; |
be0b9bb7 | 110 | } |
bfc9a610 | 111 | |
be0b9bb7 | 112 | if (connect(fd, (struct sockaddr*)&addr, addr_len) == -1) { |
2b87da3b | 113 | error("Couldn't connect to EGD socket \"%s\": %s", |
be0b9bb7 | 114 | addr.sun_path, strerror(errno)); |
6a951840 | 115 | goto done; |
be0b9bb7 | 116 | } |
bfc9a610 | 117 | |
be0b9bb7 | 118 | /* Send blocking read request to EGD */ |
119 | msg[0] = 0x02; | |
120 | msg[1] = len; | |
121 | ||
122 | if (atomicio(write, fd, msg, sizeof(msg)) != sizeof(msg)) { | |
6a951840 | 123 | if (errno == EPIPE && errors < 10) { |
124 | close(fd); | |
125 | errors++; | |
126 | goto reopen; | |
127 | } | |
2b87da3b | 128 | error("Couldn't write to EGD socket \"%s\": %s", |
be0b9bb7 | 129 | EGD_SOCKET, strerror(errno)); |
6a951840 | 130 | goto done; |
be0b9bb7 | 131 | } |
bfc9a610 | 132 | |
be0b9bb7 | 133 | if (atomicio(read, fd, buf, len) != len) { |
6a951840 | 134 | if (errno == EPIPE && errors < 10) { |
135 | close(fd); | |
136 | errors++; | |
137 | goto reopen; | |
138 | } | |
2b87da3b | 139 | error("Couldn't read from EGD socket \"%s\": %s", |
be0b9bb7 | 140 | EGD_SOCKET, strerror(errno)); |
6a951840 | 141 | goto done; |
be0b9bb7 | 142 | } |
2b87da3b | 143 | |
6a951840 | 144 | rval = 1; |
145 | done: | |
2adddc78 | 146 | mysignal(SIGPIPE, old_sigpipe); |
6a951840 | 147 | if (fd != -1) |
148 | close(fd); | |
149 | return(rval); | |
bfc9a610 | 150 | } |
151 | #else /* !EGD_SOCKET */ | |
152 | #ifdef RANDOM_POOL | |
153 | /* Collect entropy from /dev/urandom or pipe */ | |
be0b9bb7 | 154 | int get_random_bytes(unsigned char *buf, int len) |
bfc9a610 | 155 | { |
be0b9bb7 | 156 | int random_pool; |
bfc9a610 | 157 | |
be0b9bb7 | 158 | random_pool = open(RANDOM_POOL, O_RDONLY); |
bfc9a610 | 159 | if (random_pool == -1) { |
2b87da3b | 160 | error("Couldn't open random pool \"%s\": %s", |
be0b9bb7 | 161 | RANDOM_POOL, strerror(errno)); |
162 | return(0); | |
bfc9a610 | 163 | } |
2b87da3b | 164 | |
be0b9bb7 | 165 | if (atomicio(read, random_pool, buf, len) != len) { |
2b87da3b | 166 | error("Couldn't read from random pool \"%s\": %s", |
be0b9bb7 | 167 | RANDOM_POOL, strerror(errno)); |
168 | close(random_pool); | |
169 | return(0); | |
170 | } | |
2b87da3b | 171 | |
be0b9bb7 | 172 | close(random_pool); |
2b87da3b | 173 | |
be0b9bb7 | 174 | return(1); |
bfc9a610 | 175 | } |
176 | #endif /* RANDOM_POOL */ | |
177 | #endif /* EGD_SOCKET */ | |
178 | ||
48c99b2c | 179 | /* |
180 | * Seed OpenSSL's random number pool from Kernel random number generator | |
181 | * or EGD | |
182 | */ | |
183 | void | |
184 | seed_rng(void) | |
185 | { | |
186 | char buf[32]; | |
2b87da3b | 187 | |
48c99b2c | 188 | debug("Seeding random number generator"); |
be0b9bb7 | 189 | |
b5b3f75d | 190 | if (!get_random_bytes(buf, sizeof(buf))) { |
191 | if (!RAND_status()) | |
192 | fatal("Entropy collection failed and entropy exhausted"); | |
193 | } else { | |
194 | RAND_add(buf, sizeof(buf), sizeof(buf)); | |
195 | } | |
2b87da3b | 196 | |
48c99b2c | 197 | memset(buf, '\0', sizeof(buf)); |
198 | } | |
199 | ||
c7c72446 | 200 | void init_rng(void) |
201 | { | |
202 | check_openssl_version(); | |
203 | } | |
264dce47 | 204 | |
48c99b2c | 205 | #else /* defined(EGD_SOCKET) || defined(RANDOM_POOL) */ |
206 | ||
2b87da3b | 207 | /* |
bfc9a610 | 208 | * FIXME: proper entropy estimations. All current values are guesses |
b7a87eea | 209 | * FIXME: (ATL) do estimates at compile time? |
bfc9a610 | 210 | * FIXME: More entropy sources |
211 | */ | |
212 | ||
b7a87eea | 213 | /* slow command timeouts (all in milliseconds) */ |
214 | /* static int entropy_timeout_default = ENTROPY_TIMEOUT_MSEC; */ | |
215 | static int entropy_timeout_current = ENTROPY_TIMEOUT_MSEC; | |
216 | ||
d3083fbd | 217 | static int prng_seed_saved = 0; |
264dce47 | 218 | static int prng_initialised = 0; |
219 | uid_t original_uid; | |
bfc9a610 | 220 | |
221 | typedef struct | |
222 | { | |
223 | /* Proportion of data that is entropy */ | |
224 | double rate; | |
b7a87eea | 225 | /* Counter goes positive if this command times out */ |
226 | unsigned int badness; | |
227 | /* Increases by factor of two each timeout */ | |
228 | unsigned int sticky_badness; | |
bfc9a610 | 229 | /* Path to executable */ |
d3083fbd | 230 | char *path; |
bfc9a610 | 231 | /* argv to pass to executable */ |
d3083fbd | 232 | char *args[5]; |
ad85db64 | 233 | /* full command string (debug) */ |
234 | char *cmdstring; | |
bfc9a610 | 235 | } entropy_source_t; |
236 | ||
b7a87eea | 237 | double stir_from_system(void); |
238 | double stir_from_programs(void); | |
239 | double stir_gettimeofday(double entropy_estimate); | |
240 | double stir_clock(double entropy_estimate); | |
241 | double stir_rusage(int who, double entropy_estimate); | |
242 | double hash_output_from_command(entropy_source_t *src, char *hash); | |
243 | ||
d3083fbd | 244 | /* this is initialised from a file, by prng_read_commands() */ |
245 | entropy_source_t *entropy_sources = NULL; | |
bfc9a610 | 246 | |
2b87da3b | 247 | double |
bfc9a610 | 248 | stir_from_system(void) |
249 | { | |
250 | double total_entropy_estimate; | |
251 | long int i; | |
2b87da3b | 252 | |
bfc9a610 | 253 | total_entropy_estimate = 0; |
2b87da3b | 254 | |
bfc9a610 | 255 | i = getpid(); |
cbd7492e | 256 | RAND_add(&i, sizeof(i), 0.5); |
bfc9a610 | 257 | total_entropy_estimate += 0.1; |
2b87da3b | 258 | |
bfc9a610 | 259 | i = getppid(); |
cbd7492e | 260 | RAND_add(&i, sizeof(i), 0.5); |
bfc9a610 | 261 | total_entropy_estimate += 0.1; |
262 | ||
263 | i = getuid(); | |
264 | RAND_add(&i, sizeof(i), 0.0); | |
265 | i = getgid(); | |
266 | RAND_add(&i, sizeof(i), 0.0); | |
267 | ||
268 | total_entropy_estimate += stir_gettimeofday(1.0); | |
cbd7492e | 269 | total_entropy_estimate += stir_clock(0.5); |
bfc9a610 | 270 | total_entropy_estimate += stir_rusage(RUSAGE_SELF, 2.0); |
271 | ||
272 | return(total_entropy_estimate); | |
273 | } | |
274 | ||
2b87da3b | 275 | double |
bfc9a610 | 276 | stir_from_programs(void) |
277 | { | |
278 | int i; | |
279 | int c; | |
280 | double entropy_estimate; | |
281 | double total_entropy_estimate; | |
282 | char hash[SHA_DIGEST_LENGTH]; | |
283 | ||
bfc9a610 | 284 | total_entropy_estimate = 0; |
48c99b2c | 285 | for(i = 0; i < NUM_ENTROPY_RUNS; i++) { |
bfc9a610 | 286 | c = 0; |
287 | while (entropy_sources[c].path != NULL) { | |
bfc9a610 | 288 | |
b7a87eea | 289 | if (!entropy_sources[c].badness) { |
290 | /* Hash output from command */ | |
291 | entropy_estimate = hash_output_from_command(&entropy_sources[c], hash); | |
292 | ||
293 | /* Scale back entropy estimate according to command's rate */ | |
294 | entropy_estimate *= entropy_sources[c].rate; | |
2b87da3b | 295 | |
b7a87eea | 296 | /* Upper bound of entropy estimate is SHA_DIGEST_LENGTH */ |
297 | if (entropy_estimate > SHA_DIGEST_LENGTH) | |
298 | entropy_estimate = SHA_DIGEST_LENGTH; | |
bfc9a610 | 299 | |
2b87da3b | 300 | /* Scale back estimates for subsequent passes through list */ |
48c99b2c | 301 | entropy_estimate /= SCALE_PER_RUN * (i + 1.0); |
2b87da3b | 302 | |
b7a87eea | 303 | /* Stir it in */ |
304 | RAND_add(hash, sizeof(hash), entropy_estimate); | |
bfc9a610 | 305 | |
2b87da3b | 306 | debug3("Got %0.2f bytes of entropy from '%s'", entropy_estimate, |
ad85db64 | 307 | entropy_sources[c].cmdstring); |
bfc9a610 | 308 | |
b7a87eea | 309 | total_entropy_estimate += entropy_estimate; |
bfc9a610 | 310 | |
311 | /* Execution times should be a little unpredictable */ | |
b7a87eea | 312 | total_entropy_estimate += stir_gettimeofday(0.05); |
313 | total_entropy_estimate += stir_clock(0.05); | |
314 | total_entropy_estimate += stir_rusage(RUSAGE_SELF, 0.1); | |
315 | total_entropy_estimate += stir_rusage(RUSAGE_CHILDREN, 0.1); | |
316 | } else { | |
22d89d24 | 317 | debug2("Command '%s' disabled (badness %d)", |
ad85db64 | 318 | entropy_sources[c].cmdstring, entropy_sources[c].badness); |
b7a87eea | 319 | |
320 | if (entropy_sources[c].badness > 0) | |
321 | entropy_sources[c].badness--; | |
322 | } | |
323 | ||
bfc9a610 | 324 | c++; |
325 | } | |
326 | } | |
2b87da3b | 327 | |
bfc9a610 | 328 | return(total_entropy_estimate); |
329 | } | |
330 | ||
331 | double | |
332 | stir_gettimeofday(double entropy_estimate) | |
333 | { | |
334 | struct timeval tv; | |
2b87da3b | 335 | |
bfc9a610 | 336 | if (gettimeofday(&tv, NULL) == -1) |
337 | fatal("Couldn't gettimeofday: %s", strerror(errno)); | |
338 | ||
339 | RAND_add(&tv, sizeof(tv), entropy_estimate); | |
2b87da3b | 340 | |
bfc9a610 | 341 | return(entropy_estimate); |
342 | } | |
343 | ||
344 | double | |
345 | stir_clock(double entropy_estimate) | |
346 | { | |
347 | #ifdef HAVE_CLOCK | |
348 | clock_t c; | |
2b87da3b | 349 | |
bfc9a610 | 350 | c = clock(); |
351 | RAND_add(&c, sizeof(c), entropy_estimate); | |
2b87da3b | 352 | |
bfc9a610 | 353 | return(entropy_estimate); |
354 | #else /* _HAVE_CLOCK */ | |
355 | return(0); | |
356 | #endif /* _HAVE_CLOCK */ | |
357 | } | |
358 | ||
359 | double | |
360 | stir_rusage(int who, double entropy_estimate) | |
361 | { | |
362 | #ifdef HAVE_GETRUSAGE | |
363 | struct rusage ru; | |
2b87da3b | 364 | |
b7a87eea | 365 | if (getrusage(who, &ru) == -1) |
cbd7492e | 366 | return(0); |
bfc9a610 | 367 | |
cbd7492e | 368 | RAND_add(&ru, sizeof(ru), entropy_estimate); |
bfc9a610 | 369 | |
370 | return(entropy_estimate); | |
371 | #else /* _HAVE_GETRUSAGE */ | |
372 | return(0); | |
373 | #endif /* _HAVE_GETRUSAGE */ | |
374 | } | |
375 | ||
ad85db64 | 376 | |
377 | static | |
378 | int | |
379 | _get_timeval_msec_difference(struct timeval *t1, struct timeval *t2) { | |
380 | int secdiff, usecdiff; | |
381 | ||
382 | secdiff = t2->tv_sec - t1->tv_sec; | |
383 | usecdiff = (secdiff*1000000) + (t2->tv_usec - t1->tv_usec); | |
384 | return (int)(usecdiff / 1000); | |
385 | } | |
386 | ||
bfc9a610 | 387 | double |
b7a87eea | 388 | hash_output_from_command(entropy_source_t *src, char *hash) |
bfc9a610 | 389 | { |
390 | static int devnull = -1; | |
391 | int p[2]; | |
b7a87eea | 392 | fd_set rdset; |
393 | int cmd_eof = 0, error_abort = 0; | |
ad85db64 | 394 | struct timeval tv_start, tv_current; |
395 | int msec_elapsed = 0; | |
bfc9a610 | 396 | pid_t pid; |
397 | int status; | |
ad85db64 | 398 | char buf[16384]; |
bfc9a610 | 399 | int bytes_read; |
400 | int total_bytes_read; | |
401 | SHA_CTX sha; | |
2b87da3b | 402 | |
22d89d24 | 403 | debug3("Reading output from \'%s\'", src->cmdstring); |
404 | ||
bfc9a610 | 405 | if (devnull == -1) { |
406 | devnull = open("/dev/null", O_RDWR); | |
407 | if (devnull == -1) | |
408 | fatal("Couldn't open /dev/null: %s", strerror(errno)); | |
409 | } | |
2b87da3b | 410 | |
bfc9a610 | 411 | if (pipe(p) == -1) |
412 | fatal("Couldn't open pipe: %s", strerror(errno)); | |
413 | ||
ad85db64 | 414 | (void)gettimeofday(&tv_start, NULL); /* record start time */ |
415 | ||
bfc9a610 | 416 | switch (pid = fork()) { |
417 | case -1: /* Error */ | |
418 | close(p[0]); | |
419 | close(p[1]); | |
420 | fatal("Couldn't fork: %s", strerror(errno)); | |
421 | /* NOTREACHED */ | |
422 | case 0: /* Child */ | |
b7a87eea | 423 | dup2(devnull, STDIN_FILENO); |
424 | dup2(p[1], STDOUT_FILENO); | |
425 | dup2(p[1], STDERR_FILENO); | |
bfc9a610 | 426 | close(p[0]); |
427 | close(p[1]); | |
428 | close(devnull); | |
429 | ||
264dce47 | 430 | setuid(original_uid); |
b7a87eea | 431 | execv(src->path, (char**)(src->args)); |
ad85db64 | 432 | debug("(child) Couldn't exec '%s': %s", src->cmdstring, |
433 | strerror(errno)); | |
bfc9a610 | 434 | _exit(-1); |
435 | default: /* Parent */ | |
436 | break; | |
437 | } | |
438 | ||
439 | RAND_add(&pid, sizeof(&pid), 0.0); | |
440 | ||
441 | close(p[1]); | |
442 | ||
443 | /* Hash output from child */ | |
444 | SHA1_Init(&sha); | |
445 | total_bytes_read = 0; | |
b7a87eea | 446 | |
447 | while (!error_abort && !cmd_eof) { | |
448 | int ret; | |
449 | struct timeval tv; | |
ad85db64 | 450 | int msec_remaining; |
451 | ||
452 | (void) gettimeofday(&tv_current, 0); | |
48c99b2c | 453 | msec_elapsed = _get_timeval_msec_difference(&tv_start, &tv_current); |
ad85db64 | 454 | if (msec_elapsed >= entropy_timeout_current) { |
455 | error_abort=1; | |
456 | continue; | |
457 | } | |
458 | msec_remaining = entropy_timeout_current - msec_elapsed; | |
b7a87eea | 459 | |
460 | FD_ZERO(&rdset); | |
461 | FD_SET(p[0], &rdset); | |
ad85db64 | 462 | tv.tv_sec = msec_remaining / 1000; |
463 | tv.tv_usec = (msec_remaining % 1000) * 1000; | |
b7a87eea | 464 | |
465 | ret = select(p[0]+1, &rdset, NULL, NULL, &tv); | |
ad85db64 | 466 | |
264dce47 | 467 | RAND_add(&tv, sizeof(tv), 0.0); |
468 | ||
b7a87eea | 469 | switch (ret) { |
470 | case 0: | |
471 | /* timer expired */ | |
472 | error_abort = 1; | |
473 | break; | |
b7a87eea | 474 | case 1: |
475 | /* command input */ | |
476 | bytes_read = read(p[0], buf, sizeof(buf)); | |
264dce47 | 477 | RAND_add(&bytes_read, sizeof(&bytes_read), 0.0); |
b7a87eea | 478 | if (bytes_read == -1) { |
479 | error_abort = 1; | |
480 | break; | |
264dce47 | 481 | } else if (bytes_read) { |
ad85db64 | 482 | SHA1_Update(&sha, buf, bytes_read); |
483 | total_bytes_read += bytes_read; | |
264dce47 | 484 | } else { |
ad85db64 | 485 | cmd_eof = 1; |
264dce47 | 486 | } |
b7a87eea | 487 | break; |
b7a87eea | 488 | case -1: |
489 | default: | |
264dce47 | 490 | /* error */ |
ad85db64 | 491 | debug("Command '%s': select() failed: %s", src->cmdstring, |
492 | strerror(errno)); | |
b7a87eea | 493 | error_abort = 1; |
494 | break; | |
264dce47 | 495 | } |
496 | } | |
b7a87eea | 497 | |
bfc9a610 | 498 | SHA1_Final(hash, &sha); |
499 | ||
500 | close(p[0]); | |
ad85db64 | 501 | |
22d89d24 | 502 | debug3("Time elapsed: %d msec", msec_elapsed); |
2b87da3b | 503 | |
bfc9a610 | 504 | if (waitpid(pid, &status, 0) == -1) { |
22d89d24 | 505 | error("Couldn't wait for child '%s' completion: %s", src->cmdstring, |
ad85db64 | 506 | strerror(errno)); |
b7a87eea | 507 | return(0.0); |
bfc9a610 | 508 | } |
509 | ||
510 | RAND_add(&status, sizeof(&status), 0.0); | |
511 | ||
b7a87eea | 512 | if (error_abort) { |
513 | /* closing p[0] on timeout causes the entropy command to | |
514 | * SIGPIPE. Take whatever output we got, and mark this command | |
515 | * as slow */ | |
22d89d24 | 516 | debug2("Command '%s' timed out", src->cmdstring); |
b7a87eea | 517 | src->sticky_badness *= 2; |
518 | src->badness = src->sticky_badness; | |
bfc9a610 | 519 | return(total_bytes_read); |
b7a87eea | 520 | } |
521 | ||
522 | if (WIFEXITED(status)) { | |
523 | if (WEXITSTATUS(status)==0) { | |
524 | return(total_bytes_read); | |
525 | } else { | |
2b87da3b | 526 | debug2("Command '%s' exit status was %d", src->cmdstring, |
48c99b2c | 527 | WEXITSTATUS(status)); |
b7a87eea | 528 | src->badness = src->sticky_badness = 128; |
529 | return (0.0); | |
530 | } | |
531 | } else if (WIFSIGNALED(status)) { | |
2b87da3b | 532 | debug2("Command '%s' returned on uncaught signal %d !", src->cmdstring, |
48c99b2c | 533 | status); |
b7a87eea | 534 | src->badness = src->sticky_badness = 128; |
535 | return(0.0); | |
536 | } else | |
537 | return(0.0); | |
538 | } | |
539 | ||
540 | /* | |
541 | * prng seedfile functions | |
542 | */ | |
543 | int | |
544 | prng_check_seedfile(char *filename) { | |
545 | ||
546 | struct stat st; | |
547 | ||
548 | /* FIXME raceable: eg replace seed between this stat and subsequent open */ | |
549 | /* Not such a problem because we don't trust the seed file anyway */ | |
550 | if (lstat(filename, &st) == -1) { | |
5b2d4b75 | 551 | /* Give up on hard errors */ |
b7a87eea | 552 | if (errno != ENOENT) |
2b87da3b | 553 | debug("WARNING: Couldn't stat random seed file \"%s\": %s", |
5b2d4b75 | 554 | filename, strerror(errno)); |
b7a87eea | 555 | |
556 | return(0); | |
557 | } | |
558 | ||
559 | /* regular file? */ | |
560 | if (!S_ISREG(st.st_mode)) | |
561 | fatal("PRNG seedfile %.100s is not a regular file", filename); | |
562 | ||
563 | /* mode 0600, owned by root or the current user? */ | |
5b2d4b75 | 564 | if (((st.st_mode & 0177) != 0) || !(st.st_uid == original_uid)) { |
565 | debug("WARNING: PRNG seedfile %.100s must be mode 0600, owned by uid %d", | |
b7a87eea | 566 | filename, getuid()); |
5b2d4b75 | 567 | return(0); |
568 | } | |
2b87da3b | 569 | |
b7a87eea | 570 | return(1); |
571 | } | |
572 | ||
573 | void | |
574 | prng_write_seedfile(void) { | |
575 | int fd; | |
576 | char seed[1024]; | |
577 | char filename[1024]; | |
578 | struct passwd *pw; | |
579 | ||
580 | /* Don't bother if we have already saved a seed */ | |
581 | if (prng_seed_saved) | |
582 | return; | |
2b87da3b | 583 | |
264dce47 | 584 | setuid(original_uid); |
2b87da3b | 585 | |
52bcc044 | 586 | prng_seed_saved = 1; |
2b87da3b | 587 | |
264dce47 | 588 | pw = getpwuid(original_uid); |
b7a87eea | 589 | if (pw == NULL) |
2b87da3b | 590 | fatal("Couldn't get password entry for current user (%i): %s", |
264dce47 | 591 | original_uid, strerror(errno)); |
2b87da3b | 592 | |
b7a87eea | 593 | /* Try to ensure that the parent directory is there */ |
2b87da3b | 594 | snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir, |
effa6591 | 595 | _PATH_SSH_USER_DIR); |
b7a87eea | 596 | mkdir(filename, 0700); |
597 | ||
2b87da3b | 598 | snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir, |
b7a87eea | 599 | SSH_PRNG_SEED_FILE); |
600 | ||
601 | debug("writing PRNG seed to file %.100s", filename); | |
602 | ||
603 | RAND_bytes(seed, sizeof(seed)); | |
604 | ||
605 | /* Don't care if the seed doesn't exist */ | |
606 | prng_check_seedfile(filename); | |
2b87da3b | 607 | |
5b2d4b75 | 608 | if ((fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0600)) == -1) { |
2b87da3b | 609 | debug("WARNING: couldn't access PRNG seedfile %.100s (%.100s)", |
5b2d4b75 | 610 | filename, strerror(errno)); |
2b87da3b | 611 | } else { |
5b2d4b75 | 612 | if (atomicio(write, fd, &seed, sizeof(seed)) != sizeof(seed)) |
2b87da3b | 613 | fatal("problem writing PRNG seedfile %.100s (%.100s)", filename, |
5b2d4b75 | 614 | strerror(errno)); |
b7a87eea | 615 | |
5b2d4b75 | 616 | close(fd); |
617 | } | |
b7a87eea | 618 | } |
619 | ||
620 | void | |
621 | prng_read_seedfile(void) { | |
622 | int fd; | |
623 | char seed[1024]; | |
624 | char filename[1024]; | |
625 | struct passwd *pw; | |
2b87da3b | 626 | |
264dce47 | 627 | pw = getpwuid(original_uid); |
b7a87eea | 628 | if (pw == NULL) |
2b87da3b | 629 | fatal("Couldn't get password entry for current user (%i): %s", |
264dce47 | 630 | original_uid, strerror(errno)); |
2b87da3b | 631 | |
632 | snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir, | |
b7a87eea | 633 | SSH_PRNG_SEED_FILE); |
634 | ||
635 | debug("loading PRNG seed from file %.100s", filename); | |
636 | ||
637 | if (!prng_check_seedfile(filename)) { | |
52ce34a2 | 638 | verbose("Random seed file not found or not valid, ignoring."); |
b7a87eea | 639 | return; |
640 | } | |
641 | ||
642 | /* open the file and read in the seed */ | |
643 | fd = open(filename, O_RDONLY); | |
644 | if (fd == -1) | |
2b87da3b | 645 | fatal("could not open PRNG seedfile %.100s (%.100s)", filename, |
b7a87eea | 646 | strerror(errno)); |
647 | ||
648 | if (atomicio(read, fd, &seed, sizeof(seed)) != sizeof(seed)) { | |
649 | verbose("invalid or short read from PRNG seedfile %.100s - ignoring", | |
650 | filename); | |
651 | memset(seed, '\0', sizeof(seed)); | |
652 | } | |
653 | close(fd); | |
654 | ||
655 | /* stir in the seed, with estimated entropy zero */ | |
656 | RAND_add(&seed, sizeof(seed), 0.0); | |
bfc9a610 | 657 | } |
b7a87eea | 658 | |
d3083fbd | 659 | |
660 | /* | |
661 | * entropy command initialisation functions | |
662 | */ | |
d3083fbd | 663 | int |
664 | prng_read_commands(char *cmdfilename) | |
665 | { | |
666 | FILE *f; | |
d3083fbd | 667 | char *cp; |
48c99b2c | 668 | char line[1024]; |
669 | char cmd[1024]; | |
670 | char path[256]; | |
d3083fbd | 671 | int linenum; |
d3083fbd | 672 | int num_cmds = 64; |
673 | int cur_cmd = 0; | |
48c99b2c | 674 | double est; |
675 | entropy_source_t *entcmd; | |
d3083fbd | 676 | |
677 | f = fopen(cmdfilename, "r"); | |
678 | if (!f) { | |
679 | fatal("couldn't read entropy commands file %.100s: %.100s", | |
680 | cmdfilename, strerror(errno)); | |
681 | } | |
682 | ||
d3083fbd | 683 | entcmd = (entropy_source_t *)xmalloc(num_cmds * sizeof(entropy_source_t)); |
684 | memset(entcmd, '\0', num_cmds * sizeof(entropy_source_t)); | |
685 | ||
48c99b2c | 686 | /* Read in file */ |
687 | linenum = 0; | |
d3083fbd | 688 | while (fgets(line, sizeof(line), f)) { |
48c99b2c | 689 | int arg; |
690 | char *argv; | |
691 | ||
d3083fbd | 692 | linenum++; |
693 | ||
694 | /* skip leading whitespace, test for blank line or comment */ | |
695 | cp = line + strspn(line, WHITESPACE); | |
696 | if ((*cp == 0) || (*cp == '#')) | |
697 | continue; /* done with this line */ | |
698 | ||
48c99b2c | 699 | /* First non-whitespace char should be double quote delimiting */ |
700 | /* commandline */ | |
701 | if (*cp != '"') { | |
702 | error("bad entropy command, %.100s line %d", cmdfilename, | |
703 | linenum); | |
704 | continue; | |
2b87da3b | 705 | } |
d3083fbd | 706 | |
48c99b2c | 707 | /* first token, command args (incl. argv[0]) in double quotes */ |
708 | cp = strtok(cp, "\""); | |
709 | if (cp == NULL) { | |
710 | error("missing or bad command string, %.100s line %d -- ignored", | |
711 | cmdfilename, linenum); | |
712 | continue; | |
713 | } | |
714 | strlcpy(cmd, cp, sizeof(cmd)); | |
2b87da3b | 715 | |
48c99b2c | 716 | /* second token, full command path */ |
717 | if ((cp = strtok(NULL, WHITESPACE)) == NULL) { | |
718 | error("missing command path, %.100s line %d -- ignored", | |
719 | cmdfilename, linenum); | |
720 | continue; | |
721 | } | |
d3083fbd | 722 | |
48c99b2c | 723 | /* did configure mark this as dead? */ |
724 | if (strncmp("undef", cp, 5) == 0) | |
725 | continue; | |
d3083fbd | 726 | |
2b87da3b | 727 | strlcpy(path, cp, sizeof(path)); |
48c99b2c | 728 | |
729 | /* third token, entropy rate estimate for this command */ | |
730 | if ((cp = strtok(NULL, WHITESPACE)) == NULL) { | |
731 | error("missing entropy estimate, %.100s line %d -- ignored", | |
732 | cmdfilename, linenum); | |
733 | continue; | |
734 | } | |
735 | est = strtod(cp, &argv); | |
736 | ||
737 | /* end of line */ | |
738 | if ((cp = strtok(NULL, WHITESPACE)) != NULL) { | |
2b87da3b | 739 | error("garbage at end of line %d in %.100s -- ignored", linenum, |
48c99b2c | 740 | cmdfilename); |
d3083fbd | 741 | continue; |
742 | } | |
48c99b2c | 743 | |
744 | /* save the command for debug messages */ | |
745 | entcmd[cur_cmd].cmdstring = xstrdup(cmd); | |
2b87da3b | 746 | |
48c99b2c | 747 | /* split the command args */ |
748 | cp = strtok(cmd, WHITESPACE); | |
749 | arg = 0; | |
750 | argv = NULL; | |
751 | do { | |
752 | char *s = (char*)xmalloc(strlen(cp) + 1); | |
753 | strncpy(s, cp, strlen(cp) + 1); | |
754 | entcmd[cur_cmd].args[arg] = s; | |
755 | arg++; | |
756 | } while ((arg < 5) && (cp = strtok(NULL, WHITESPACE))); | |
2b87da3b | 757 | |
48c99b2c | 758 | if (strtok(NULL, WHITESPACE)) |
759 | error("ignored extra command elements (max 5), %.100s line %d", | |
760 | cmdfilename, linenum); | |
761 | ||
762 | /* Copy the command path and rate estimate */ | |
763 | entcmd[cur_cmd].path = xstrdup(path); | |
764 | entcmd[cur_cmd].rate = est; | |
765 | ||
766 | /* Initialise other values */ | |
767 | entcmd[cur_cmd].sticky_badness = 1; | |
768 | ||
769 | cur_cmd++; | |
770 | ||
771 | /* If we've filled the array, reallocate it twice the size */ | |
772 | /* Do this now because even if this we're on the last command, | |
773 | we need another slot to mark the last entry */ | |
774 | if (cur_cmd == num_cmds) { | |
775 | num_cmds *= 2; | |
776 | entcmd = xrealloc(entcmd, num_cmds * sizeof(entropy_source_t)); | |
777 | } | |
d3083fbd | 778 | } |
779 | ||
780 | /* zero the last entry */ | |
781 | memset(&entcmd[cur_cmd], '\0', sizeof(entropy_source_t)); | |
48c99b2c | 782 | |
d3083fbd | 783 | /* trim to size */ |
784 | entropy_sources = xrealloc(entcmd, (cur_cmd+1) * sizeof(entropy_source_t)); | |
785 | ||
264dce47 | 786 | debug("Loaded %d entropy commands from %.100s", cur_cmd, cmdfilename); |
d3083fbd | 787 | |
788 | return (cur_cmd >= MIN_ENTROPY_SOURCES); | |
789 | } | |
790 | ||
b7a87eea | 791 | /* |
792 | * Write a keyfile at exit | |
2b87da3b | 793 | */ |
b7a87eea | 794 | void |
795 | prng_seed_cleanup(void *junk) | |
796 | { | |
797 | prng_write_seedfile(); | |
798 | } | |
799 | ||
bfc9a610 | 800 | /* |
b7a87eea | 801 | * Conditionally Seed OpenSSL's random number pool from |
802 | * syscalls and program output | |
bfc9a610 | 803 | */ |
804 | void | |
805 | seed_rng(void) | |
806 | { | |
e1a023df | 807 | mysig_t old_sigchld_handler; |
d3083fbd | 808 | |
264dce47 | 809 | if (!prng_initialised) |
810 | fatal("RNG not initialised"); | |
2b87da3b | 811 | |
a64009ad | 812 | /* Make sure some other sigchld handler doesn't reap our entropy */ |
813 | /* commands */ | |
e1a023df | 814 | old_sigchld_handler = mysignal(SIGCHLD, SIG_DFL); |
a64009ad | 815 | |
264dce47 | 816 | debug("Seeded RNG with %i bytes from programs", (int)stir_from_programs()); |
817 | debug("Seeded RNG with %i bytes from system calls", (int)stir_from_system()); | |
818 | ||
819 | if (!RAND_status()) | |
820 | fatal("Not enough entropy in RNG"); | |
b7a87eea | 821 | |
e1a023df | 822 | mysignal(SIGCHLD, old_sigchld_handler); |
a64009ad | 823 | |
ad85db64 | 824 | if (!RAND_status()) |
825 | fatal("Couldn't initialise builtin random number generator -- exiting."); | |
264dce47 | 826 | } |
ad85db64 | 827 | |
2b87da3b | 828 | void init_rng(void) |
264dce47 | 829 | { |
e879a080 | 830 | int original_euid; |
2b87da3b | 831 | |
c7c72446 | 832 | check_openssl_version(); |
833 | ||
264dce47 | 834 | original_uid = getuid(); |
e879a080 | 835 | original_euid = geteuid(); |
264dce47 | 836 | |
837 | /* Read in collection commands */ | |
838 | if (!prng_read_commands(SSH_PRNG_COMMAND_FILE)) | |
839 | fatal("PRNG initialisation failed -- exiting."); | |
840 | ||
841 | /* Set ourselves up to save a seed upon exit */ | |
2b87da3b | 842 | prng_seed_saved = 0; |
e879a080 | 843 | |
844 | /* Give up privs while reading seed file */ | |
e9a13ac1 | 845 | #ifdef SAVED_IDS_WORK_WITH_SETEUID |
e879a080 | 846 | if ((original_uid != original_euid) && (seteuid(original_uid) == -1)) |
847 | fatal("Couldn't give up privileges"); | |
e9a13ac1 | 848 | #else /* SAVED_IDS_WORK_WITH_SETEUID */ |
849 | /* | |
850 | * Propagate the privileged uid to all of our uids. | |
851 | * Set the effective uid to the given (unprivileged) uid. | |
852 | */ | |
d5c4c52e | 853 | if (original_uid != original_euid && (setuid(original_euid) == -1 || |
854 | seteuid(original_uid) == -1)) | |
e9a13ac1 | 855 | fatal("Couldn't give up privileges"); |
856 | #endif /* SAVED_IDS_WORK_WITH_SETEUID */ | |
2b87da3b | 857 | |
264dce47 | 858 | prng_read_seedfile(); |
e879a080 | 859 | |
e9a13ac1 | 860 | #ifdef SAVED_IDS_WORK_WITH_SETEUID |
e879a080 | 861 | if ((original_uid != original_euid) && (seteuid(original_euid) == -1)) |
862 | fatal("Couldn't restore privileges"); | |
e9a13ac1 | 863 | #else /* SAVED_IDS_WORK_WITH_SETEUID */ |
864 | /* | |
865 | * We are unable to restore the real uid to its unprivileged value. | |
866 | * Propagate the real uid (usually more privileged) to effective uid | |
867 | * as well. | |
868 | */ | |
d5c4c52e | 869 | if (original_uid != original_euid && (seteuid(original_euid) == -1 || |
870 | setuid(original_uid) == -1)) | |
e9a13ac1 | 871 | fatal("Couldn't restore privileges"); |
872 | #endif /* SAVED_IDS_WORK_WITH_SETEUID */ | |
e879a080 | 873 | |
264dce47 | 874 | fatal_add_cleanup(prng_seed_cleanup, NULL); |
875 | atexit(prng_write_seedfile); | |
876 | ||
877 | prng_initialised = 1; | |
bfc9a610 | 878 | } |
264dce47 | 879 | |
bfc9a610 | 880 | #endif /* defined(EGD_SOCKET) || defined(RANDOM_POOL) */ |