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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 | ||
e339aa53 | 71 | void |
72 | check_openssl_version(void) | |
c7c72446 | 73 | { |
74 | if (SSLeay() != OPENSSL_VERSION_NUMBER) | |
32e0cb42 | 75 | fatal("OpenSSL version mismatch. Built against %lx, you " |
76 | "have %lx", OPENSSL_VERSION_NUMBER, SSLeay()); | |
c7c72446 | 77 | } |
78 | ||
9bdd5929 | 79 | #if defined(PRNGD_SOCKET) || defined(PRNGD_PORT) |
80 | # define USE_PRNGD | |
81 | #endif | |
c7c72446 | 82 | |
9bdd5929 | 83 | #if defined(USE_PRNGD) || defined(RANDOM_POOL) |
48c99b2c | 84 | |
9bdd5929 | 85 | #ifdef USE_PRNGD |
86 | /* Collect entropy from PRNGD/EGD */ | |
e339aa53 | 87 | int |
88 | get_random_bytes(unsigned char *buf, int len) | |
bfc9a610 | 89 | { |
be0b9bb7 | 90 | int fd; |
91 | char msg[2]; | |
9bdd5929 | 92 | #ifdef PRNGD_PORT |
93 | struct sockaddr_in addr; | |
94 | #else | |
bfc9a610 | 95 | struct sockaddr_un addr; |
9bdd5929 | 96 | #endif |
6a951840 | 97 | int addr_len, rval, errors; |
e1a023df | 98 | mysig_t old_sigpipe; |
bfc9a610 | 99 | |
9bdd5929 | 100 | memset(&addr, '\0', sizeof(addr)); |
101 | ||
102 | #ifdef PRNGD_PORT | |
103 | addr.sin_family = AF_INET; | |
104 | addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK); | |
105 | addr.sin_port = htons(PRNGD_PORT); | |
106 | addr_len = sizeof(struct sockaddr_in); | |
107 | #else /* use IP socket PRNGD_SOCKET instead */ | |
be0b9bb7 | 108 | /* Sanity checks */ |
9bdd5929 | 109 | if (sizeof(PRNGD_SOCKET) > sizeof(addr.sun_path)) |
bfc9a610 | 110 | fatal("Random pool path is too long"); |
be0b9bb7 | 111 | if (len > 255) |
9bdd5929 | 112 | fatal("Too many bytes to read from PRNGD"); |
be0b9bb7 | 113 | |
be0b9bb7 | 114 | addr.sun_family = AF_UNIX; |
9bdd5929 | 115 | strlcpy(addr.sun_path, PRNGD_SOCKET, sizeof(addr.sun_path)); |
116 | addr_len = offsetof(struct sockaddr_un, sun_path) + | |
117 | sizeof(PRNGD_SOCKET); | |
118 | #endif | |
2b87da3b | 119 | |
e1a023df | 120 | old_sigpipe = mysignal(SIGPIPE, SIG_IGN); |
6a951840 | 121 | |
122 | errors = rval = 0; | |
123 | reopen: | |
9bdd5929 | 124 | #ifdef PRNGD_PORT |
125 | fd = socket(addr.sin_family, SOCK_STREAM, 0); | |
126 | if (fd == -1) { | |
127 | error("Couldn't create AF_INET socket: %s", strerror(errno)); | |
128 | goto done; | |
129 | } | |
130 | #else | |
131 | fd = socket(addr.sun_family, SOCK_STREAM, 0); | |
be0b9bb7 | 132 | if (fd == -1) { |
133 | error("Couldn't create AF_UNIX socket: %s", strerror(errno)); | |
6a951840 | 134 | goto done; |
be0b9bb7 | 135 | } |
9bdd5929 | 136 | #endif |
bfc9a610 | 137 | |
be0b9bb7 | 138 | if (connect(fd, (struct sockaddr*)&addr, addr_len) == -1) { |
9bdd5929 | 139 | #ifdef PRNGD_PORT |
140 | error("Couldn't connect to PRNGD port %d: %s", | |
141 | PRNGD_PORT, strerror(errno)); | |
142 | #else | |
143 | error("Couldn't connect to PRNGD socket \"%s\": %s", | |
144 | addr.sun_path, strerror(errno)); | |
145 | #endif | |
6a951840 | 146 | goto done; |
be0b9bb7 | 147 | } |
bfc9a610 | 148 | |
9bdd5929 | 149 | /* Send blocking read request to PRNGD */ |
be0b9bb7 | 150 | msg[0] = 0x02; |
151 | msg[1] = len; | |
152 | ||
153 | if (atomicio(write, fd, msg, sizeof(msg)) != sizeof(msg)) { | |
6a951840 | 154 | if (errno == EPIPE && errors < 10) { |
155 | close(fd); | |
156 | errors++; | |
157 | goto reopen; | |
158 | } | |
9bdd5929 | 159 | error("Couldn't write to PRNGD socket: %s", |
160 | strerror(errno)); | |
6a951840 | 161 | goto done; |
be0b9bb7 | 162 | } |
bfc9a610 | 163 | |
be0b9bb7 | 164 | if (atomicio(read, fd, buf, len) != len) { |
6a951840 | 165 | if (errno == EPIPE && errors < 10) { |
166 | close(fd); | |
167 | errors++; | |
168 | goto reopen; | |
169 | } | |
9bdd5929 | 170 | error("Couldn't read from PRNGD socket: %s", |
171 | strerror(errno)); | |
6a951840 | 172 | goto done; |
be0b9bb7 | 173 | } |
2b87da3b | 174 | |
6a951840 | 175 | rval = 1; |
176 | done: | |
2adddc78 | 177 | mysignal(SIGPIPE, old_sigpipe); |
6a951840 | 178 | if (fd != -1) |
179 | close(fd); | |
180 | return(rval); | |
bfc9a610 | 181 | } |
9bdd5929 | 182 | #else /* !USE_PRNGD */ |
bfc9a610 | 183 | #ifdef RANDOM_POOL |
184 | /* Collect entropy from /dev/urandom or pipe */ | |
e339aa53 | 185 | int |
186 | get_random_bytes(unsigned char *buf, int len) | |
bfc9a610 | 187 | { |
be0b9bb7 | 188 | int random_pool; |
bfc9a610 | 189 | |
be0b9bb7 | 190 | random_pool = open(RANDOM_POOL, O_RDONLY); |
bfc9a610 | 191 | if (random_pool == -1) { |
2b87da3b | 192 | error("Couldn't open random pool \"%s\": %s", |
be0b9bb7 | 193 | RANDOM_POOL, strerror(errno)); |
194 | return(0); | |
bfc9a610 | 195 | } |
2b87da3b | 196 | |
be0b9bb7 | 197 | if (atomicio(read, random_pool, buf, len) != len) { |
2b87da3b | 198 | error("Couldn't read from random pool \"%s\": %s", |
be0b9bb7 | 199 | RANDOM_POOL, strerror(errno)); |
200 | close(random_pool); | |
201 | return(0); | |
202 | } | |
2b87da3b | 203 | |
be0b9bb7 | 204 | close(random_pool); |
2b87da3b | 205 | |
be0b9bb7 | 206 | return(1); |
bfc9a610 | 207 | } |
208 | #endif /* RANDOM_POOL */ | |
9bdd5929 | 209 | #endif /* USE_PRNGD */ |
bfc9a610 | 210 | |
48c99b2c | 211 | /* |
212 | * Seed OpenSSL's random number pool from Kernel random number generator | |
9bdd5929 | 213 | * or PRNGD/EGD |
48c99b2c | 214 | */ |
215 | void | |
216 | seed_rng(void) | |
217 | { | |
9bdd5929 | 218 | unsigned char buf[32]; |
2b87da3b | 219 | |
48c99b2c | 220 | debug("Seeding random number generator"); |
be0b9bb7 | 221 | |
b5b3f75d | 222 | if (!get_random_bytes(buf, sizeof(buf))) { |
223 | if (!RAND_status()) | |
224 | fatal("Entropy collection failed and entropy exhausted"); | |
225 | } else { | |
226 | RAND_add(buf, sizeof(buf), sizeof(buf)); | |
227 | } | |
2b87da3b | 228 | |
48c99b2c | 229 | memset(buf, '\0', sizeof(buf)); |
230 | } | |
231 | ||
e339aa53 | 232 | void |
233 | init_rng(void) | |
c7c72446 | 234 | { |
235 | check_openssl_version(); | |
236 | } | |
264dce47 | 237 | |
9bdd5929 | 238 | #else /* defined(USE_PRNGD) || defined(RANDOM_POOL) */ |
48c99b2c | 239 | |
2b87da3b | 240 | /* |
bfc9a610 | 241 | * FIXME: proper entropy estimations. All current values are guesses |
b7a87eea | 242 | * FIXME: (ATL) do estimates at compile time? |
bfc9a610 | 243 | * FIXME: More entropy sources |
244 | */ | |
245 | ||
b7a87eea | 246 | /* slow command timeouts (all in milliseconds) */ |
247 | /* static int entropy_timeout_default = ENTROPY_TIMEOUT_MSEC; */ | |
248 | static int entropy_timeout_current = ENTROPY_TIMEOUT_MSEC; | |
249 | ||
d3083fbd | 250 | static int prng_seed_saved = 0; |
264dce47 | 251 | static int prng_initialised = 0; |
252 | uid_t original_uid; | |
bfc9a610 | 253 | |
254 | typedef struct | |
255 | { | |
256 | /* Proportion of data that is entropy */ | |
257 | double rate; | |
b7a87eea | 258 | /* Counter goes positive if this command times out */ |
259 | unsigned int badness; | |
260 | /* Increases by factor of two each timeout */ | |
261 | unsigned int sticky_badness; | |
bfc9a610 | 262 | /* Path to executable */ |
d3083fbd | 263 | char *path; |
bfc9a610 | 264 | /* argv to pass to executable */ |
d3083fbd | 265 | char *args[5]; |
ad85db64 | 266 | /* full command string (debug) */ |
267 | char *cmdstring; | |
bfc9a610 | 268 | } entropy_source_t; |
269 | ||
b7a87eea | 270 | double stir_from_system(void); |
271 | double stir_from_programs(void); | |
272 | double stir_gettimeofday(double entropy_estimate); | |
273 | double stir_clock(double entropy_estimate); | |
274 | double stir_rusage(int who, double entropy_estimate); | |
275 | double hash_output_from_command(entropy_source_t *src, char *hash); | |
276 | ||
d3083fbd | 277 | /* this is initialised from a file, by prng_read_commands() */ |
278 | entropy_source_t *entropy_sources = NULL; | |
bfc9a610 | 279 | |
2b87da3b | 280 | double |
bfc9a610 | 281 | stir_from_system(void) |
282 | { | |
283 | double total_entropy_estimate; | |
284 | long int i; | |
2b87da3b | 285 | |
bfc9a610 | 286 | total_entropy_estimate = 0; |
2b87da3b | 287 | |
bfc9a610 | 288 | i = getpid(); |
cbd7492e | 289 | RAND_add(&i, sizeof(i), 0.5); |
bfc9a610 | 290 | total_entropy_estimate += 0.1; |
2b87da3b | 291 | |
bfc9a610 | 292 | i = getppid(); |
cbd7492e | 293 | RAND_add(&i, sizeof(i), 0.5); |
bfc9a610 | 294 | total_entropy_estimate += 0.1; |
295 | ||
296 | i = getuid(); | |
297 | RAND_add(&i, sizeof(i), 0.0); | |
298 | i = getgid(); | |
299 | RAND_add(&i, sizeof(i), 0.0); | |
300 | ||
301 | total_entropy_estimate += stir_gettimeofday(1.0); | |
cbd7492e | 302 | total_entropy_estimate += stir_clock(0.5); |
bfc9a610 | 303 | total_entropy_estimate += stir_rusage(RUSAGE_SELF, 2.0); |
304 | ||
305 | return(total_entropy_estimate); | |
306 | } | |
307 | ||
2b87da3b | 308 | double |
bfc9a610 | 309 | stir_from_programs(void) |
310 | { | |
311 | int i; | |
312 | int c; | |
313 | double entropy_estimate; | |
314 | double total_entropy_estimate; | |
315 | char hash[SHA_DIGEST_LENGTH]; | |
316 | ||
bfc9a610 | 317 | total_entropy_estimate = 0; |
48c99b2c | 318 | for(i = 0; i < NUM_ENTROPY_RUNS; i++) { |
bfc9a610 | 319 | c = 0; |
320 | while (entropy_sources[c].path != NULL) { | |
bfc9a610 | 321 | |
b7a87eea | 322 | if (!entropy_sources[c].badness) { |
323 | /* Hash output from command */ | |
324 | entropy_estimate = hash_output_from_command(&entropy_sources[c], hash); | |
325 | ||
326 | /* Scale back entropy estimate according to command's rate */ | |
327 | entropy_estimate *= entropy_sources[c].rate; | |
2b87da3b | 328 | |
b7a87eea | 329 | /* Upper bound of entropy estimate is SHA_DIGEST_LENGTH */ |
330 | if (entropy_estimate > SHA_DIGEST_LENGTH) | |
331 | entropy_estimate = SHA_DIGEST_LENGTH; | |
bfc9a610 | 332 | |
2b87da3b | 333 | /* Scale back estimates for subsequent passes through list */ |
48c99b2c | 334 | entropy_estimate /= SCALE_PER_RUN * (i + 1.0); |
2b87da3b | 335 | |
b7a87eea | 336 | /* Stir it in */ |
337 | RAND_add(hash, sizeof(hash), entropy_estimate); | |
bfc9a610 | 338 | |
2b87da3b | 339 | debug3("Got %0.2f bytes of entropy from '%s'", entropy_estimate, |
ad85db64 | 340 | entropy_sources[c].cmdstring); |
bfc9a610 | 341 | |
b7a87eea | 342 | total_entropy_estimate += entropy_estimate; |
bfc9a610 | 343 | |
344 | /* Execution times should be a little unpredictable */ | |
b7a87eea | 345 | total_entropy_estimate += stir_gettimeofday(0.05); |
346 | total_entropy_estimate += stir_clock(0.05); | |
347 | total_entropy_estimate += stir_rusage(RUSAGE_SELF, 0.1); | |
348 | total_entropy_estimate += stir_rusage(RUSAGE_CHILDREN, 0.1); | |
349 | } else { | |
22d89d24 | 350 | debug2("Command '%s' disabled (badness %d)", |
ad85db64 | 351 | entropy_sources[c].cmdstring, entropy_sources[c].badness); |
b7a87eea | 352 | |
353 | if (entropy_sources[c].badness > 0) | |
354 | entropy_sources[c].badness--; | |
355 | } | |
356 | ||
bfc9a610 | 357 | c++; |
358 | } | |
359 | } | |
2b87da3b | 360 | |
bfc9a610 | 361 | return(total_entropy_estimate); |
362 | } | |
363 | ||
364 | double | |
365 | stir_gettimeofday(double entropy_estimate) | |
366 | { | |
367 | struct timeval tv; | |
2b87da3b | 368 | |
bfc9a610 | 369 | if (gettimeofday(&tv, NULL) == -1) |
370 | fatal("Couldn't gettimeofday: %s", strerror(errno)); | |
371 | ||
372 | RAND_add(&tv, sizeof(tv), entropy_estimate); | |
2b87da3b | 373 | |
bfc9a610 | 374 | return(entropy_estimate); |
375 | } | |
376 | ||
377 | double | |
378 | stir_clock(double entropy_estimate) | |
379 | { | |
380 | #ifdef HAVE_CLOCK | |
381 | clock_t c; | |
2b87da3b | 382 | |
bfc9a610 | 383 | c = clock(); |
384 | RAND_add(&c, sizeof(c), entropy_estimate); | |
2b87da3b | 385 | |
bfc9a610 | 386 | return(entropy_estimate); |
387 | #else /* _HAVE_CLOCK */ | |
388 | return(0); | |
389 | #endif /* _HAVE_CLOCK */ | |
390 | } | |
391 | ||
392 | double | |
393 | stir_rusage(int who, double entropy_estimate) | |
394 | { | |
395 | #ifdef HAVE_GETRUSAGE | |
396 | struct rusage ru; | |
2b87da3b | 397 | |
b7a87eea | 398 | if (getrusage(who, &ru) == -1) |
cbd7492e | 399 | return(0); |
bfc9a610 | 400 | |
cbd7492e | 401 | RAND_add(&ru, sizeof(ru), entropy_estimate); |
bfc9a610 | 402 | |
403 | return(entropy_estimate); | |
404 | #else /* _HAVE_GETRUSAGE */ | |
405 | return(0); | |
406 | #endif /* _HAVE_GETRUSAGE */ | |
407 | } | |
408 | ||
ad85db64 | 409 | |
e339aa53 | 410 | static int |
ad85db64 | 411 | _get_timeval_msec_difference(struct timeval *t1, struct timeval *t2) { |
412 | int secdiff, usecdiff; | |
413 | ||
414 | secdiff = t2->tv_sec - t1->tv_sec; | |
415 | usecdiff = (secdiff*1000000) + (t2->tv_usec - t1->tv_usec); | |
416 | return (int)(usecdiff / 1000); | |
417 | } | |
418 | ||
bfc9a610 | 419 | double |
b7a87eea | 420 | hash_output_from_command(entropy_source_t *src, char *hash) |
bfc9a610 | 421 | { |
422 | static int devnull = -1; | |
423 | int p[2]; | |
b7a87eea | 424 | fd_set rdset; |
425 | int cmd_eof = 0, error_abort = 0; | |
ad85db64 | 426 | struct timeval tv_start, tv_current; |
427 | int msec_elapsed = 0; | |
bfc9a610 | 428 | pid_t pid; |
429 | int status; | |
ad85db64 | 430 | char buf[16384]; |
bfc9a610 | 431 | int bytes_read; |
432 | int total_bytes_read; | |
433 | SHA_CTX sha; | |
2b87da3b | 434 | |
22d89d24 | 435 | debug3("Reading output from \'%s\'", src->cmdstring); |
436 | ||
bfc9a610 | 437 | if (devnull == -1) { |
438 | devnull = open("/dev/null", O_RDWR); | |
439 | if (devnull == -1) | |
440 | fatal("Couldn't open /dev/null: %s", strerror(errno)); | |
441 | } | |
2b87da3b | 442 | |
bfc9a610 | 443 | if (pipe(p) == -1) |
444 | fatal("Couldn't open pipe: %s", strerror(errno)); | |
445 | ||
ad85db64 | 446 | (void)gettimeofday(&tv_start, NULL); /* record start time */ |
447 | ||
bfc9a610 | 448 | switch (pid = fork()) { |
449 | case -1: /* Error */ | |
450 | close(p[0]); | |
451 | close(p[1]); | |
452 | fatal("Couldn't fork: %s", strerror(errno)); | |
453 | /* NOTREACHED */ | |
454 | case 0: /* Child */ | |
b7a87eea | 455 | dup2(devnull, STDIN_FILENO); |
456 | dup2(p[1], STDOUT_FILENO); | |
457 | dup2(p[1], STDERR_FILENO); | |
bfc9a610 | 458 | close(p[0]); |
459 | close(p[1]); | |
460 | close(devnull); | |
461 | ||
264dce47 | 462 | setuid(original_uid); |
b7a87eea | 463 | execv(src->path, (char**)(src->args)); |
ad85db64 | 464 | debug("(child) Couldn't exec '%s': %s", src->cmdstring, |
465 | strerror(errno)); | |
bfc9a610 | 466 | _exit(-1); |
467 | default: /* Parent */ | |
468 | break; | |
469 | } | |
470 | ||
471 | RAND_add(&pid, sizeof(&pid), 0.0); | |
472 | ||
473 | close(p[1]); | |
474 | ||
475 | /* Hash output from child */ | |
476 | SHA1_Init(&sha); | |
477 | total_bytes_read = 0; | |
b7a87eea | 478 | |
479 | while (!error_abort && !cmd_eof) { | |
480 | int ret; | |
481 | struct timeval tv; | |
ad85db64 | 482 | int msec_remaining; |
483 | ||
484 | (void) gettimeofday(&tv_current, 0); | |
48c99b2c | 485 | msec_elapsed = _get_timeval_msec_difference(&tv_start, &tv_current); |
ad85db64 | 486 | if (msec_elapsed >= entropy_timeout_current) { |
487 | error_abort=1; | |
488 | continue; | |
489 | } | |
490 | msec_remaining = entropy_timeout_current - msec_elapsed; | |
b7a87eea | 491 | |
492 | FD_ZERO(&rdset); | |
493 | FD_SET(p[0], &rdset); | |
ad85db64 | 494 | tv.tv_sec = msec_remaining / 1000; |
495 | tv.tv_usec = (msec_remaining % 1000) * 1000; | |
b7a87eea | 496 | |
497 | ret = select(p[0]+1, &rdset, NULL, NULL, &tv); | |
ad85db64 | 498 | |
264dce47 | 499 | RAND_add(&tv, sizeof(tv), 0.0); |
500 | ||
b7a87eea | 501 | switch (ret) { |
502 | case 0: | |
503 | /* timer expired */ | |
504 | error_abort = 1; | |
505 | break; | |
b7a87eea | 506 | case 1: |
507 | /* command input */ | |
508 | bytes_read = read(p[0], buf, sizeof(buf)); | |
264dce47 | 509 | RAND_add(&bytes_read, sizeof(&bytes_read), 0.0); |
b7a87eea | 510 | if (bytes_read == -1) { |
511 | error_abort = 1; | |
512 | break; | |
264dce47 | 513 | } else if (bytes_read) { |
ad85db64 | 514 | SHA1_Update(&sha, buf, bytes_read); |
515 | total_bytes_read += bytes_read; | |
264dce47 | 516 | } else { |
ad85db64 | 517 | cmd_eof = 1; |
264dce47 | 518 | } |
b7a87eea | 519 | break; |
b7a87eea | 520 | case -1: |
521 | default: | |
264dce47 | 522 | /* error */ |
ad85db64 | 523 | debug("Command '%s': select() failed: %s", src->cmdstring, |
524 | strerror(errno)); | |
b7a87eea | 525 | error_abort = 1; |
526 | break; | |
264dce47 | 527 | } |
528 | } | |
b7a87eea | 529 | |
bfc9a610 | 530 | SHA1_Final(hash, &sha); |
531 | ||
532 | close(p[0]); | |
ad85db64 | 533 | |
22d89d24 | 534 | debug3("Time elapsed: %d msec", msec_elapsed); |
2b87da3b | 535 | |
bfc9a610 | 536 | if (waitpid(pid, &status, 0) == -1) { |
22d89d24 | 537 | error("Couldn't wait for child '%s' completion: %s", src->cmdstring, |
ad85db64 | 538 | strerror(errno)); |
b7a87eea | 539 | return(0.0); |
bfc9a610 | 540 | } |
541 | ||
542 | RAND_add(&status, sizeof(&status), 0.0); | |
543 | ||
b7a87eea | 544 | if (error_abort) { |
545 | /* closing p[0] on timeout causes the entropy command to | |
546 | * SIGPIPE. Take whatever output we got, and mark this command | |
547 | * as slow */ | |
22d89d24 | 548 | debug2("Command '%s' timed out", src->cmdstring); |
b7a87eea | 549 | src->sticky_badness *= 2; |
550 | src->badness = src->sticky_badness; | |
bfc9a610 | 551 | return(total_bytes_read); |
b7a87eea | 552 | } |
553 | ||
554 | if (WIFEXITED(status)) { | |
555 | if (WEXITSTATUS(status)==0) { | |
556 | return(total_bytes_read); | |
557 | } else { | |
2b87da3b | 558 | debug2("Command '%s' exit status was %d", src->cmdstring, |
48c99b2c | 559 | WEXITSTATUS(status)); |
b7a87eea | 560 | src->badness = src->sticky_badness = 128; |
561 | return (0.0); | |
562 | } | |
563 | } else if (WIFSIGNALED(status)) { | |
2b87da3b | 564 | debug2("Command '%s' returned on uncaught signal %d !", src->cmdstring, |
48c99b2c | 565 | status); |
b7a87eea | 566 | src->badness = src->sticky_badness = 128; |
567 | return(0.0); | |
568 | } else | |
569 | return(0.0); | |
570 | } | |
571 | ||
572 | /* | |
573 | * prng seedfile functions | |
574 | */ | |
575 | int | |
576 | prng_check_seedfile(char *filename) { | |
577 | ||
578 | struct stat st; | |
579 | ||
580 | /* FIXME raceable: eg replace seed between this stat and subsequent open */ | |
581 | /* Not such a problem because we don't trust the seed file anyway */ | |
582 | if (lstat(filename, &st) == -1) { | |
5b2d4b75 | 583 | /* Give up on hard errors */ |
b7a87eea | 584 | if (errno != ENOENT) |
2b87da3b | 585 | debug("WARNING: Couldn't stat random seed file \"%s\": %s", |
5b2d4b75 | 586 | filename, strerror(errno)); |
b7a87eea | 587 | |
588 | return(0); | |
589 | } | |
590 | ||
591 | /* regular file? */ | |
592 | if (!S_ISREG(st.st_mode)) | |
593 | fatal("PRNG seedfile %.100s is not a regular file", filename); | |
594 | ||
595 | /* mode 0600, owned by root or the current user? */ | |
5b2d4b75 | 596 | if (((st.st_mode & 0177) != 0) || !(st.st_uid == original_uid)) { |
597 | debug("WARNING: PRNG seedfile %.100s must be mode 0600, owned by uid %d", | |
b7a87eea | 598 | filename, getuid()); |
5b2d4b75 | 599 | return(0); |
600 | } | |
2b87da3b | 601 | |
b7a87eea | 602 | return(1); |
603 | } | |
604 | ||
605 | void | |
606 | prng_write_seedfile(void) { | |
607 | int fd; | |
608 | char seed[1024]; | |
609 | char filename[1024]; | |
610 | struct passwd *pw; | |
611 | ||
612 | /* Don't bother if we have already saved a seed */ | |
613 | if (prng_seed_saved) | |
614 | return; | |
2b87da3b | 615 | |
264dce47 | 616 | setuid(original_uid); |
2b87da3b | 617 | |
52bcc044 | 618 | prng_seed_saved = 1; |
2b87da3b | 619 | |
264dce47 | 620 | pw = getpwuid(original_uid); |
b7a87eea | 621 | if (pw == NULL) |
2b87da3b | 622 | fatal("Couldn't get password entry for current user (%i): %s", |
264dce47 | 623 | original_uid, strerror(errno)); |
2b87da3b | 624 | |
b7a87eea | 625 | /* Try to ensure that the parent directory is there */ |
2b87da3b | 626 | snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir, |
effa6591 | 627 | _PATH_SSH_USER_DIR); |
b7a87eea | 628 | mkdir(filename, 0700); |
629 | ||
2b87da3b | 630 | snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir, |
b7a87eea | 631 | SSH_PRNG_SEED_FILE); |
632 | ||
633 | debug("writing PRNG seed to file %.100s", filename); | |
634 | ||
635 | RAND_bytes(seed, sizeof(seed)); | |
636 | ||
637 | /* Don't care if the seed doesn't exist */ | |
638 | prng_check_seedfile(filename); | |
2b87da3b | 639 | |
5b2d4b75 | 640 | if ((fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0600)) == -1) { |
2b87da3b | 641 | debug("WARNING: couldn't access PRNG seedfile %.100s (%.100s)", |
5b2d4b75 | 642 | filename, strerror(errno)); |
2b87da3b | 643 | } else { |
5b2d4b75 | 644 | if (atomicio(write, fd, &seed, sizeof(seed)) != sizeof(seed)) |
2b87da3b | 645 | fatal("problem writing PRNG seedfile %.100s (%.100s)", filename, |
5b2d4b75 | 646 | strerror(errno)); |
b7a87eea | 647 | |
5b2d4b75 | 648 | close(fd); |
649 | } | |
b7a87eea | 650 | } |
651 | ||
652 | void | |
653 | prng_read_seedfile(void) { | |
654 | int fd; | |
655 | char seed[1024]; | |
656 | char filename[1024]; | |
657 | struct passwd *pw; | |
2b87da3b | 658 | |
264dce47 | 659 | pw = getpwuid(original_uid); |
b7a87eea | 660 | if (pw == NULL) |
2b87da3b | 661 | fatal("Couldn't get password entry for current user (%i): %s", |
264dce47 | 662 | original_uid, strerror(errno)); |
2b87da3b | 663 | |
664 | snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir, | |
b7a87eea | 665 | SSH_PRNG_SEED_FILE); |
666 | ||
667 | debug("loading PRNG seed from file %.100s", filename); | |
668 | ||
669 | if (!prng_check_seedfile(filename)) { | |
52ce34a2 | 670 | verbose("Random seed file not found or not valid, ignoring."); |
b7a87eea | 671 | return; |
672 | } | |
673 | ||
674 | /* open the file and read in the seed */ | |
675 | fd = open(filename, O_RDONLY); | |
676 | if (fd == -1) | |
2b87da3b | 677 | fatal("could not open PRNG seedfile %.100s (%.100s)", filename, |
b7a87eea | 678 | strerror(errno)); |
679 | ||
680 | if (atomicio(read, fd, &seed, sizeof(seed)) != sizeof(seed)) { | |
681 | verbose("invalid or short read from PRNG seedfile %.100s - ignoring", | |
682 | filename); | |
683 | memset(seed, '\0', sizeof(seed)); | |
684 | } | |
685 | close(fd); | |
686 | ||
687 | /* stir in the seed, with estimated entropy zero */ | |
688 | RAND_add(&seed, sizeof(seed), 0.0); | |
bfc9a610 | 689 | } |
b7a87eea | 690 | |
d3083fbd | 691 | |
692 | /* | |
693 | * entropy command initialisation functions | |
694 | */ | |
d3083fbd | 695 | int |
696 | prng_read_commands(char *cmdfilename) | |
697 | { | |
698 | FILE *f; | |
d3083fbd | 699 | char *cp; |
48c99b2c | 700 | char line[1024]; |
701 | char cmd[1024]; | |
702 | char path[256]; | |
d3083fbd | 703 | int linenum; |
d3083fbd | 704 | int num_cmds = 64; |
705 | int cur_cmd = 0; | |
48c99b2c | 706 | double est; |
707 | entropy_source_t *entcmd; | |
d3083fbd | 708 | |
709 | f = fopen(cmdfilename, "r"); | |
710 | if (!f) { | |
711 | fatal("couldn't read entropy commands file %.100s: %.100s", | |
712 | cmdfilename, strerror(errno)); | |
713 | } | |
714 | ||
d3083fbd | 715 | entcmd = (entropy_source_t *)xmalloc(num_cmds * sizeof(entropy_source_t)); |
716 | memset(entcmd, '\0', num_cmds * sizeof(entropy_source_t)); | |
717 | ||
48c99b2c | 718 | /* Read in file */ |
719 | linenum = 0; | |
d3083fbd | 720 | while (fgets(line, sizeof(line), f)) { |
48c99b2c | 721 | int arg; |
722 | char *argv; | |
723 | ||
d3083fbd | 724 | linenum++; |
725 | ||
726 | /* skip leading whitespace, test for blank line or comment */ | |
727 | cp = line + strspn(line, WHITESPACE); | |
728 | if ((*cp == 0) || (*cp == '#')) | |
729 | continue; /* done with this line */ | |
730 | ||
48c99b2c | 731 | /* First non-whitespace char should be double quote delimiting */ |
732 | /* commandline */ | |
733 | if (*cp != '"') { | |
734 | error("bad entropy command, %.100s line %d", cmdfilename, | |
735 | linenum); | |
736 | continue; | |
2b87da3b | 737 | } |
d3083fbd | 738 | |
48c99b2c | 739 | /* first token, command args (incl. argv[0]) in double quotes */ |
740 | cp = strtok(cp, "\""); | |
741 | if (cp == NULL) { | |
742 | error("missing or bad command string, %.100s line %d -- ignored", | |
743 | cmdfilename, linenum); | |
744 | continue; | |
745 | } | |
746 | strlcpy(cmd, cp, sizeof(cmd)); | |
2b87da3b | 747 | |
48c99b2c | 748 | /* second token, full command path */ |
749 | if ((cp = strtok(NULL, WHITESPACE)) == NULL) { | |
750 | error("missing command path, %.100s line %d -- ignored", | |
751 | cmdfilename, linenum); | |
752 | continue; | |
753 | } | |
d3083fbd | 754 | |
48c99b2c | 755 | /* did configure mark this as dead? */ |
756 | if (strncmp("undef", cp, 5) == 0) | |
757 | continue; | |
d3083fbd | 758 | |
2b87da3b | 759 | strlcpy(path, cp, sizeof(path)); |
48c99b2c | 760 | |
761 | /* third token, entropy rate estimate for this command */ | |
762 | if ((cp = strtok(NULL, WHITESPACE)) == NULL) { | |
763 | error("missing entropy estimate, %.100s line %d -- ignored", | |
764 | cmdfilename, linenum); | |
765 | continue; | |
766 | } | |
767 | est = strtod(cp, &argv); | |
768 | ||
769 | /* end of line */ | |
770 | if ((cp = strtok(NULL, WHITESPACE)) != NULL) { | |
2b87da3b | 771 | error("garbage at end of line %d in %.100s -- ignored", linenum, |
48c99b2c | 772 | cmdfilename); |
d3083fbd | 773 | continue; |
774 | } | |
48c99b2c | 775 | |
776 | /* save the command for debug messages */ | |
777 | entcmd[cur_cmd].cmdstring = xstrdup(cmd); | |
2b87da3b | 778 | |
48c99b2c | 779 | /* split the command args */ |
780 | cp = strtok(cmd, WHITESPACE); | |
781 | arg = 0; | |
782 | argv = NULL; | |
783 | do { | |
784 | char *s = (char*)xmalloc(strlen(cp) + 1); | |
785 | strncpy(s, cp, strlen(cp) + 1); | |
786 | entcmd[cur_cmd].args[arg] = s; | |
787 | arg++; | |
788 | } while ((arg < 5) && (cp = strtok(NULL, WHITESPACE))); | |
2b87da3b | 789 | |
48c99b2c | 790 | if (strtok(NULL, WHITESPACE)) |
791 | error("ignored extra command elements (max 5), %.100s line %d", | |
792 | cmdfilename, linenum); | |
793 | ||
794 | /* Copy the command path and rate estimate */ | |
795 | entcmd[cur_cmd].path = xstrdup(path); | |
796 | entcmd[cur_cmd].rate = est; | |
797 | ||
798 | /* Initialise other values */ | |
799 | entcmd[cur_cmd].sticky_badness = 1; | |
800 | ||
801 | cur_cmd++; | |
802 | ||
803 | /* If we've filled the array, reallocate it twice the size */ | |
804 | /* Do this now because even if this we're on the last command, | |
805 | we need another slot to mark the last entry */ | |
806 | if (cur_cmd == num_cmds) { | |
807 | num_cmds *= 2; | |
808 | entcmd = xrealloc(entcmd, num_cmds * sizeof(entropy_source_t)); | |
809 | } | |
d3083fbd | 810 | } |
811 | ||
812 | /* zero the last entry */ | |
813 | memset(&entcmd[cur_cmd], '\0', sizeof(entropy_source_t)); | |
48c99b2c | 814 | |
d3083fbd | 815 | /* trim to size */ |
816 | entropy_sources = xrealloc(entcmd, (cur_cmd+1) * sizeof(entropy_source_t)); | |
817 | ||
264dce47 | 818 | debug("Loaded %d entropy commands from %.100s", cur_cmd, cmdfilename); |
d3083fbd | 819 | |
820 | return (cur_cmd >= MIN_ENTROPY_SOURCES); | |
821 | } | |
822 | ||
b7a87eea | 823 | /* |
824 | * Write a keyfile at exit | |
2b87da3b | 825 | */ |
b7a87eea | 826 | void |
827 | prng_seed_cleanup(void *junk) | |
828 | { | |
829 | prng_write_seedfile(); | |
830 | } | |
831 | ||
bfc9a610 | 832 | /* |
b7a87eea | 833 | * Conditionally Seed OpenSSL's random number pool from |
834 | * syscalls and program output | |
bfc9a610 | 835 | */ |
836 | void | |
837 | seed_rng(void) | |
838 | { | |
e1a023df | 839 | mysig_t old_sigchld_handler; |
d3083fbd | 840 | |
264dce47 | 841 | if (!prng_initialised) |
842 | fatal("RNG not initialised"); | |
2b87da3b | 843 | |
a64009ad | 844 | /* Make sure some other sigchld handler doesn't reap our entropy */ |
845 | /* commands */ | |
e1a023df | 846 | old_sigchld_handler = mysignal(SIGCHLD, SIG_DFL); |
a64009ad | 847 | |
e339aa53 | 848 | debug("Seeded RNG with %i bytes from programs", |
849 | (int)stir_from_programs()); | |
850 | debug("Seeded RNG with %i bytes from system calls", | |
851 | (int)stir_from_system()); | |
264dce47 | 852 | |
853 | if (!RAND_status()) | |
854 | fatal("Not enough entropy in RNG"); | |
b7a87eea | 855 | |
e1a023df | 856 | mysignal(SIGCHLD, old_sigchld_handler); |
a64009ad | 857 | |
ad85db64 | 858 | if (!RAND_status()) |
859 | fatal("Couldn't initialise builtin random number generator -- exiting."); | |
264dce47 | 860 | } |
ad85db64 | 861 | |
e339aa53 | 862 | void |
863 | init_rng(void) | |
264dce47 | 864 | { |
e879a080 | 865 | int original_euid; |
2b87da3b | 866 | |
c7c72446 | 867 | check_openssl_version(); |
868 | ||
264dce47 | 869 | original_uid = getuid(); |
e879a080 | 870 | original_euid = geteuid(); |
264dce47 | 871 | |
872 | /* Read in collection commands */ | |
873 | if (!prng_read_commands(SSH_PRNG_COMMAND_FILE)) | |
874 | fatal("PRNG initialisation failed -- exiting."); | |
875 | ||
876 | /* Set ourselves up to save a seed upon exit */ | |
2b87da3b | 877 | prng_seed_saved = 0; |
e879a080 | 878 | |
879 | /* Give up privs while reading seed file */ | |
e9a13ac1 | 880 | #ifdef SAVED_IDS_WORK_WITH_SETEUID |
e879a080 | 881 | if ((original_uid != original_euid) && (seteuid(original_uid) == -1)) |
882 | fatal("Couldn't give up privileges"); | |
e9a13ac1 | 883 | #else /* SAVED_IDS_WORK_WITH_SETEUID */ |
884 | /* | |
885 | * Propagate the privileged uid to all of our uids. | |
886 | * Set the effective uid to the given (unprivileged) uid. | |
887 | */ | |
d5c4c52e | 888 | if (original_uid != original_euid && (setuid(original_euid) == -1 || |
889 | seteuid(original_uid) == -1)) | |
e9a13ac1 | 890 | fatal("Couldn't give up privileges"); |
891 | #endif /* SAVED_IDS_WORK_WITH_SETEUID */ | |
2b87da3b | 892 | |
264dce47 | 893 | prng_read_seedfile(); |
e879a080 | 894 | |
e9a13ac1 | 895 | #ifdef SAVED_IDS_WORK_WITH_SETEUID |
e879a080 | 896 | if ((original_uid != original_euid) && (seteuid(original_euid) == -1)) |
897 | fatal("Couldn't restore privileges"); | |
e9a13ac1 | 898 | #else /* SAVED_IDS_WORK_WITH_SETEUID */ |
899 | /* | |
900 | * We are unable to restore the real uid to its unprivileged value. | |
901 | * Propagate the real uid (usually more privileged) to effective uid | |
902 | * as well. | |
903 | */ | |
d5c4c52e | 904 | if (original_uid != original_euid && (seteuid(original_euid) == -1 || |
905 | setuid(original_uid) == -1)) | |
e9a13ac1 | 906 | fatal("Couldn't restore privileges"); |
907 | #endif /* SAVED_IDS_WORK_WITH_SETEUID */ | |
e879a080 | 908 | |
264dce47 | 909 | fatal_add_cleanup(prng_seed_cleanup, NULL); |
910 | atexit(prng_write_seedfile); | |
911 | ||
912 | prng_initialised = 1; | |
bfc9a610 | 913 | } |
264dce47 | 914 | |
9bdd5929 | 915 | #endif /* defined(USE_PRNGD) || defined(RANDOM_POOL) */ |