]>
Commit | Line | Data |
---|---|---|
46058ce2 | 1 | /* |
40f64e6f | 2 | * Copyright (c) 2001-2002 Damien Miller. All rights reserved. |
46058ce2 | 3 | * |
4 | * Redistribution and use in source and binary forms, with or without | |
5 | * modification, are permitted provided that the following conditions | |
6 | * are met: | |
7 | * 1. Redistributions of source code must retain the above copyright | |
8 | * notice, this list of conditions and the following disclaimer. | |
9 | * 2. Redistributions in binary form must reproduce the above copyright | |
10 | * notice, this list of conditions and the following disclaimer in the | |
11 | * documentation and/or other materials provided with the distribution. | |
12 | * | |
13 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR | |
14 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES | |
15 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. | |
16 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, | |
17 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
18 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
19 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
20 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
21 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF | |
22 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
23 | */ | |
24 | ||
25 | #include "includes.h" | |
26 | ||
cb2c6179 | 27 | #include <sys/types.h> |
28 | #include <sys/resource.h> | |
29 | #include <sys/stat.h> | |
30 | #include <sys/wait.h> | |
31 | ||
32 | #ifdef HAVE_SYS_UN_H | |
33 | # include <sys/un.h> | |
34 | #endif | |
35 | ||
36 | #include <signal.h> | |
37 | ||
46058ce2 | 38 | #include <openssl/rand.h> |
39 | #include <openssl/sha.h> | |
40 | #include <openssl/crypto.h> | |
41 | ||
42 | /* SunOS 4.4.4 needs this */ | |
43 | #ifdef HAVE_FLOATINGPOINT_H | |
44 | # include <floatingpoint.h> | |
45 | #endif /* HAVE_FLOATINGPOINT_H */ | |
46 | ||
47 | #include "misc.h" | |
48 | #include "xmalloc.h" | |
49 | #include "atomicio.h" | |
50 | #include "pathnames.h" | |
51 | #include "log.h" | |
52 | ||
53 | RCSID("$Id$"); | |
54 | ||
40f64e6f | 55 | /* Number of bytes we write out */ |
56 | #define OUTPUT_SEED_SIZE 48 | |
57 | ||
58 | /* Length of on-disk seedfiles */ | |
59 | #define SEED_FILE_SIZE 1024 | |
60 | ||
61 | /* Maximum number of command-line arguments to read from file */ | |
62 | #define NUM_ARGS 10 | |
63 | ||
64 | /* Minimum number of usable commands to be considered sufficient */ | |
65 | #define MIN_ENTROPY_SOURCES 16 | |
46058ce2 | 66 | |
40f64e6f | 67 | /* Path to on-disk seed file (relative to user's home directory */ |
46058ce2 | 68 | #ifndef SSH_PRNG_SEED_FILE |
69 | # define SSH_PRNG_SEED_FILE _PATH_SSH_USER_DIR"/prng_seed" | |
40f64e6f | 70 | #endif |
71 | ||
72 | /* Path to PRNG commands list */ | |
46058ce2 | 73 | #ifndef SSH_PRNG_COMMAND_FILE |
2a8a6488 | 74 | # define SSH_PRNG_COMMAND_FILE SSHDIR "/ssh_prng_cmds" |
40f64e6f | 75 | #endif |
46058ce2 | 76 | |
40f64e6f | 77 | extern char *__progname; |
40f64e6f | 78 | |
46058ce2 | 79 | #define WHITESPACE " \t\n" |
80 | ||
81 | #ifndef RUSAGE_SELF | |
82 | # define RUSAGE_SELF 0 | |
83 | #endif | |
84 | #ifndef RUSAGE_CHILDREN | |
85 | # define RUSAGE_CHILDREN 0 | |
86 | #endif | |
87 | ||
49d7ed32 | 88 | #if !defined(PRNGD_SOCKET) && !defined(PRNGD_PORT) |
40f64e6f | 89 | # define USE_SEED_FILES |
46058ce2 | 90 | #endif |
91 | ||
40f64e6f | 92 | typedef struct { |
93 | /* Proportion of data that is entropy */ | |
94 | double rate; | |
95 | /* Counter goes positive if this command times out */ | |
96 | unsigned int badness; | |
97 | /* Increases by factor of two each timeout */ | |
98 | unsigned int sticky_badness; | |
99 | /* Path to executable */ | |
100 | char *path; | |
101 | /* argv to pass to executable */ | |
102 | char *args[NUM_ARGS]; /* XXX: arbitrary limit */ | |
103 | /* full command string (debug) */ | |
104 | char *cmdstring; | |
105 | } entropy_cmd_t; | |
106 | ||
107 | /* slow command timeouts (all in milliseconds) */ | |
108 | /* static int entropy_timeout_default = ENTROPY_TIMEOUT_MSEC; */ | |
109 | static int entropy_timeout_current = ENTROPY_TIMEOUT_MSEC; | |
110 | ||
111 | /* this is initialised from a file, by prng_read_commands() */ | |
112 | static entropy_cmd_t *entropy_cmds = NULL; | |
113 | ||
114 | /* Prototypes */ | |
115 | double stir_from_system(void); | |
116 | double stir_from_programs(void); | |
117 | double stir_gettimeofday(double entropy_estimate); | |
118 | double stir_clock(double entropy_estimate); | |
119 | double stir_rusage(int who, double entropy_estimate); | |
75131bbd | 120 | double hash_command_output(entropy_cmd_t *src, unsigned char *hash); |
aff51935 | 121 | int get_random_bytes_prngd(unsigned char *buf, int len, |
40f64e6f | 122 | unsigned short tcp_port, char *socket_path); |
123 | ||
124 | /* | |
125 | * Collect 'len' bytes of entropy into 'buf' from PRNGD/EGD daemon | |
126 | * listening either on 'tcp_port', or via Unix domain socket at * | |
127 | * 'socket_path'. | |
aff51935 | 128 | * Either a non-zero tcp_port or a non-null socket_path must be |
40f64e6f | 129 | * supplied. |
130 | * Returns 0 on success, -1 on error | |
131 | */ | |
46058ce2 | 132 | int |
aff51935 | 133 | get_random_bytes_prngd(unsigned char *buf, int len, |
40f64e6f | 134 | unsigned short tcp_port, char *socket_path) |
46058ce2 | 135 | { |
40f64e6f | 136 | int fd, addr_len, rval, errors; |
44d71ad5 | 137 | u_char msg[2]; |
40f64e6f | 138 | struct sockaddr_storage addr; |
139 | struct sockaddr_in *addr_in = (struct sockaddr_in *)&addr; | |
140 | struct sockaddr_un *addr_un = (struct sockaddr_un *)&addr; | |
46058ce2 | 141 | mysig_t old_sigpipe; |
142 | ||
40f64e6f | 143 | /* Sanity checks */ |
144 | if (socket_path == NULL && tcp_port == 0) | |
145 | fatal("You must specify a port or a socket"); | |
146 | if (socket_path != NULL && | |
147 | strlen(socket_path) >= sizeof(addr_un->sun_path)) | |
148 | fatal("Random pool path is too long"); | |
44d71ad5 | 149 | if (len <= 0 || len > 255) |
150 | fatal("Too many bytes (%d) to read from PRNGD", len); | |
46058ce2 | 151 | |
152 | memset(&addr, '\0', sizeof(addr)); | |
153 | ||
40f64e6f | 154 | if (tcp_port != 0) { |
155 | addr_in->sin_family = AF_INET; | |
156 | addr_in->sin_addr.s_addr = htonl(INADDR_LOOPBACK); | |
157 | addr_in->sin_port = htons(tcp_port); | |
158 | addr_len = sizeof(*addr_in); | |
159 | } else { | |
160 | addr_un->sun_family = AF_UNIX; | |
161 | strlcpy(addr_un->sun_path, socket_path, | |
162 | sizeof(addr_un->sun_path)); | |
163 | addr_len = offsetof(struct sockaddr_un, sun_path) + | |
164 | strlen(socket_path) + 1; | |
165 | } | |
46058ce2 | 166 | |
167 | old_sigpipe = mysignal(SIGPIPE, SIG_IGN); | |
168 | ||
40f64e6f | 169 | errors = 0; |
170 | rval = -1; | |
46058ce2 | 171 | reopen: |
40f64e6f | 172 | fd = socket(addr.ss_family, SOCK_STREAM, 0); |
46058ce2 | 173 | if (fd == -1) { |
40f64e6f | 174 | error("Couldn't create socket: %s", strerror(errno)); |
46058ce2 | 175 | goto done; |
176 | } | |
46058ce2 | 177 | |
178 | if (connect(fd, (struct sockaddr*)&addr, addr_len) == -1) { | |
40f64e6f | 179 | if (tcp_port != 0) { |
180 | error("Couldn't connect to PRNGD port %d: %s", | |
181 | tcp_port, strerror(errno)); | |
182 | } else { | |
183 | error("Couldn't connect to PRNGD socket \"%s\": %s", | |
184 | addr_un->sun_path, strerror(errno)); | |
185 | } | |
46058ce2 | 186 | goto done; |
187 | } | |
188 | ||
189 | /* Send blocking read request to PRNGD */ | |
190 | msg[0] = 0x02; | |
191 | msg[1] = len; | |
192 | ||
d72f7b79 | 193 | if (atomicio(vwrite, fd, msg, sizeof(msg)) != sizeof(msg)) { |
46058ce2 | 194 | if (errno == EPIPE && errors < 10) { |
195 | close(fd); | |
196 | errors++; | |
197 | goto reopen; | |
198 | } | |
199 | error("Couldn't write to PRNGD socket: %s", | |
200 | strerror(errno)); | |
201 | goto done; | |
202 | } | |
203 | ||
44d71ad5 | 204 | if (atomicio(read, fd, buf, len) != (size_t)len) { |
46058ce2 | 205 | if (errno == EPIPE && errors < 10) { |
206 | close(fd); | |
207 | errors++; | |
208 | goto reopen; | |
209 | } | |
210 | error("Couldn't read from PRNGD socket: %s", | |
211 | strerror(errno)); | |
212 | goto done; | |
213 | } | |
214 | ||
40f64e6f | 215 | rval = 0; |
46058ce2 | 216 | done: |
217 | mysignal(SIGPIPE, old_sigpipe); | |
218 | if (fd != -1) | |
219 | close(fd); | |
40f64e6f | 220 | return rval; |
46058ce2 | 221 | } |
222 | ||
1e111f05 | 223 | static int |
224 | seed_from_prngd(unsigned char *buf, size_t bytes) | |
225 | { | |
226 | #ifdef PRNGD_PORT | |
227 | debug("trying egd/prngd port %d", PRNGD_PORT); | |
228 | if (get_random_bytes_prngd(buf, bytes, PRNGD_PORT, NULL) == 0) | |
229 | return 0; | |
230 | #endif | |
231 | #ifdef PRNGD_SOCKET | |
232 | debug("trying egd/prngd socket %s", PRNGD_SOCKET); | |
233 | if (get_random_bytes_prngd(buf, bytes, 0, PRNGD_SOCKET) == 0) | |
234 | return 0; | |
235 | #endif | |
236 | return -1; | |
237 | } | |
238 | ||
46058ce2 | 239 | double |
240 | stir_gettimeofday(double entropy_estimate) | |
241 | { | |
242 | struct timeval tv; | |
243 | ||
244 | if (gettimeofday(&tv, NULL) == -1) | |
245 | fatal("Couldn't gettimeofday: %s", strerror(errno)); | |
246 | ||
247 | RAND_add(&tv, sizeof(tv), entropy_estimate); | |
248 | ||
40f64e6f | 249 | return entropy_estimate; |
46058ce2 | 250 | } |
251 | ||
252 | double | |
253 | stir_clock(double entropy_estimate) | |
254 | { | |
255 | #ifdef HAVE_CLOCK | |
256 | clock_t c; | |
257 | ||
258 | c = clock(); | |
259 | RAND_add(&c, sizeof(c), entropy_estimate); | |
260 | ||
40f64e6f | 261 | return entropy_estimate; |
46058ce2 | 262 | #else /* _HAVE_CLOCK */ |
40f64e6f | 263 | return 0; |
46058ce2 | 264 | #endif /* _HAVE_CLOCK */ |
265 | } | |
266 | ||
267 | double | |
268 | stir_rusage(int who, double entropy_estimate) | |
269 | { | |
270 | #ifdef HAVE_GETRUSAGE | |
271 | struct rusage ru; | |
272 | ||
273 | if (getrusage(who, &ru) == -1) | |
40f64e6f | 274 | return 0; |
46058ce2 | 275 | |
276 | RAND_add(&ru, sizeof(ru), entropy_estimate); | |
277 | ||
40f64e6f | 278 | return entropy_estimate; |
46058ce2 | 279 | #else /* _HAVE_GETRUSAGE */ |
40f64e6f | 280 | return 0; |
46058ce2 | 281 | #endif /* _HAVE_GETRUSAGE */ |
282 | } | |
283 | ||
46058ce2 | 284 | static int |
40f64e6f | 285 | timeval_diff(struct timeval *t1, struct timeval *t2) |
286 | { | |
46058ce2 | 287 | int secdiff, usecdiff; |
288 | ||
289 | secdiff = t2->tv_sec - t1->tv_sec; | |
290 | usecdiff = (secdiff*1000000) + (t2->tv_usec - t1->tv_usec); | |
291 | return (int)(usecdiff / 1000); | |
292 | } | |
293 | ||
294 | double | |
75131bbd | 295 | hash_command_output(entropy_cmd_t *src, unsigned char *hash) |
46058ce2 | 296 | { |
40f64e6f | 297 | char buf[8192]; |
46058ce2 | 298 | fd_set rdset; |
40f64e6f | 299 | int bytes_read, cmd_eof, error_abort, msec_elapsed, p[2]; |
300 | int status, total_bytes_read; | |
301 | static int devnull = -1; | |
46058ce2 | 302 | pid_t pid; |
46058ce2 | 303 | SHA_CTX sha; |
40f64e6f | 304 | struct timeval tv_start, tv_current; |
46058ce2 | 305 | |
306 | debug3("Reading output from \'%s\'", src->cmdstring); | |
307 | ||
308 | if (devnull == -1) { | |
309 | devnull = open("/dev/null", O_RDWR); | |
310 | if (devnull == -1) | |
aff51935 | 311 | fatal("Couldn't open /dev/null: %s", |
40f64e6f | 312 | strerror(errno)); |
46058ce2 | 313 | } |
314 | ||
315 | if (pipe(p) == -1) | |
316 | fatal("Couldn't open pipe: %s", strerror(errno)); | |
317 | ||
318 | (void)gettimeofday(&tv_start, NULL); /* record start time */ | |
319 | ||
320 | switch (pid = fork()) { | |
321 | case -1: /* Error */ | |
322 | close(p[0]); | |
323 | close(p[1]); | |
324 | fatal("Couldn't fork: %s", strerror(errno)); | |
325 | /* NOTREACHED */ | |
326 | case 0: /* Child */ | |
327 | dup2(devnull, STDIN_FILENO); | |
328 | dup2(p[1], STDOUT_FILENO); | |
329 | dup2(p[1], STDERR_FILENO); | |
330 | close(p[0]); | |
331 | close(p[1]); | |
332 | close(devnull); | |
333 | ||
334 | execv(src->path, (char**)(src->args)); | |
40f64e6f | 335 | |
aff51935 | 336 | debug("(child) Couldn't exec '%s': %s", |
40f64e6f | 337 | src->cmdstring, strerror(errno)); |
46058ce2 | 338 | _exit(-1); |
339 | default: /* Parent */ | |
340 | break; | |
341 | } | |
342 | ||
343 | RAND_add(&pid, sizeof(&pid), 0.0); | |
344 | ||
345 | close(p[1]); | |
346 | ||
347 | /* Hash output from child */ | |
348 | SHA1_Init(&sha); | |
46058ce2 | 349 | |
40f64e6f | 350 | cmd_eof = error_abort = msec_elapsed = total_bytes_read = 0; |
46058ce2 | 351 | while (!error_abort && !cmd_eof) { |
352 | int ret; | |
353 | struct timeval tv; | |
354 | int msec_remaining; | |
355 | ||
356 | (void) gettimeofday(&tv_current, 0); | |
40f64e6f | 357 | msec_elapsed = timeval_diff(&tv_start, &tv_current); |
46058ce2 | 358 | if (msec_elapsed >= entropy_timeout_current) { |
359 | error_abort=1; | |
360 | continue; | |
361 | } | |
362 | msec_remaining = entropy_timeout_current - msec_elapsed; | |
363 | ||
364 | FD_ZERO(&rdset); | |
365 | FD_SET(p[0], &rdset); | |
40f64e6f | 366 | tv.tv_sec = msec_remaining / 1000; |
46058ce2 | 367 | tv.tv_usec = (msec_remaining % 1000) * 1000; |
368 | ||
40f64e6f | 369 | ret = select(p[0] + 1, &rdset, NULL, NULL, &tv); |
46058ce2 | 370 | |
371 | RAND_add(&tv, sizeof(tv), 0.0); | |
372 | ||
373 | switch (ret) { | |
374 | case 0: | |
375 | /* timer expired */ | |
376 | error_abort = 1; | |
4e6f1c4f | 377 | kill(pid, SIGINT); |
46058ce2 | 378 | break; |
379 | case 1: | |
380 | /* command input */ | |
381 | do { | |
382 | bytes_read = read(p[0], buf, sizeof(buf)); | |
383 | } while (bytes_read == -1 && errno == EINTR); | |
384 | RAND_add(&bytes_read, sizeof(&bytes_read), 0.0); | |
385 | if (bytes_read == -1) { | |
386 | error_abort = 1; | |
387 | break; | |
388 | } else if (bytes_read) { | |
389 | SHA1_Update(&sha, buf, bytes_read); | |
390 | total_bytes_read += bytes_read; | |
391 | } else { | |
392 | cmd_eof = 1; | |
393 | } | |
394 | break; | |
395 | case -1: | |
396 | default: | |
397 | /* error */ | |
aff51935 | 398 | debug("Command '%s': select() failed: %s", |
40f64e6f | 399 | src->cmdstring, strerror(errno)); |
46058ce2 | 400 | error_abort = 1; |
401 | break; | |
402 | } | |
403 | } | |
404 | ||
405 | SHA1_Final(hash, &sha); | |
406 | ||
407 | close(p[0]); | |
408 | ||
409 | debug3("Time elapsed: %d msec", msec_elapsed); | |
410 | ||
411 | if (waitpid(pid, &status, 0) == -1) { | |
98c044d0 | 412 | error("Couldn't wait for child '%s' completion: %s", |
413 | src->cmdstring, strerror(errno)); | |
40f64e6f | 414 | return 0.0; |
46058ce2 | 415 | } |
416 | ||
417 | RAND_add(&status, sizeof(&status), 0.0); | |
418 | ||
419 | if (error_abort) { | |
40f64e6f | 420 | /* |
421 | * Closing p[0] on timeout causes the entropy command to | |
aff51935 | 422 | * SIGPIPE. Take whatever output we got, and mark this |
423 | * command as slow | |
40f64e6f | 424 | */ |
46058ce2 | 425 | debug2("Command '%s' timed out", src->cmdstring); |
426 | src->sticky_badness *= 2; | |
427 | src->badness = src->sticky_badness; | |
40f64e6f | 428 | return total_bytes_read; |
46058ce2 | 429 | } |
430 | ||
431 | if (WIFEXITED(status)) { | |
40f64e6f | 432 | if (WEXITSTATUS(status) == 0) { |
433 | return total_bytes_read; | |
46058ce2 | 434 | } else { |
40f64e6f | 435 | debug2("Command '%s' exit status was %d", |
436 | src->cmdstring, WEXITSTATUS(status)); | |
46058ce2 | 437 | src->badness = src->sticky_badness = 128; |
40f64e6f | 438 | return 0.0; |
46058ce2 | 439 | } |
440 | } else if (WIFSIGNALED(status)) { | |
40f64e6f | 441 | debug2("Command '%s' returned on uncaught signal %d !", |
442 | src->cmdstring, status); | |
46058ce2 | 443 | src->badness = src->sticky_badness = 128; |
40f64e6f | 444 | return 0.0; |
46058ce2 | 445 | } else |
40f64e6f | 446 | return 0.0; |
447 | } | |
448 | ||
449 | double | |
450 | stir_from_system(void) | |
451 | { | |
452 | double total_entropy_estimate; | |
453 | long int i; | |
454 | ||
455 | total_entropy_estimate = 0; | |
456 | ||
457 | i = getpid(); | |
458 | RAND_add(&i, sizeof(i), 0.5); | |
459 | total_entropy_estimate += 0.1; | |
460 | ||
461 | i = getppid(); | |
462 | RAND_add(&i, sizeof(i), 0.5); | |
463 | total_entropy_estimate += 0.1; | |
464 | ||
465 | i = getuid(); | |
466 | RAND_add(&i, sizeof(i), 0.0); | |
467 | i = getgid(); | |
468 | RAND_add(&i, sizeof(i), 0.0); | |
469 | ||
470 | total_entropy_estimate += stir_gettimeofday(1.0); | |
471 | total_entropy_estimate += stir_clock(0.5); | |
472 | total_entropy_estimate += stir_rusage(RUSAGE_SELF, 2.0); | |
473 | ||
474 | return total_entropy_estimate; | |
475 | } | |
476 | ||
477 | double | |
478 | stir_from_programs(void) | |
479 | { | |
480 | int c; | |
481 | double entropy, total_entropy; | |
75131bbd | 482 | unsigned char hash[SHA_DIGEST_LENGTH]; |
40f64e6f | 483 | |
484 | total_entropy = 0; | |
485 | for(c = 0; entropy_cmds[c].path != NULL; c++) { | |
486 | if (!entropy_cmds[c].badness) { | |
487 | /* Hash output from command */ | |
488 | entropy = hash_command_output(&entropy_cmds[c], | |
489 | hash); | |
490 | ||
491 | /* Scale back estimate by command's rate */ | |
492 | entropy *= entropy_cmds[c].rate; | |
493 | ||
494 | /* Upper bound of entropy is SHA_DIGEST_LENGTH */ | |
495 | if (entropy > SHA_DIGEST_LENGTH) | |
496 | entropy = SHA_DIGEST_LENGTH; | |
497 | ||
498 | /* Stir it in */ | |
499 | RAND_add(hash, sizeof(hash), entropy); | |
500 | ||
aff51935 | 501 | debug3("Got %0.2f bytes of entropy from '%s'", |
40f64e6f | 502 | entropy, entropy_cmds[c].cmdstring); |
503 | ||
504 | total_entropy += entropy; | |
505 | ||
506 | /* Execution time should be a bit unpredictable */ | |
507 | total_entropy += stir_gettimeofday(0.05); | |
508 | total_entropy += stir_clock(0.05); | |
509 | total_entropy += stir_rusage(RUSAGE_SELF, 0.1); | |
510 | total_entropy += stir_rusage(RUSAGE_CHILDREN, 0.1); | |
511 | } else { | |
512 | debug2("Command '%s' disabled (badness %d)", | |
aff51935 | 513 | entropy_cmds[c].cmdstring, |
40f64e6f | 514 | entropy_cmds[c].badness); |
515 | ||
516 | if (entropy_cmds[c].badness > 0) | |
517 | entropy_cmds[c].badness--; | |
518 | } | |
519 | } | |
520 | ||
521 | return total_entropy; | |
46058ce2 | 522 | } |
523 | ||
524 | /* | |
525 | * prng seedfile functions | |
526 | */ | |
527 | int | |
40f64e6f | 528 | prng_check_seedfile(char *filename) |
529 | { | |
46058ce2 | 530 | struct stat st; |
531 | ||
40f64e6f | 532 | /* |
aff51935 | 533 | * XXX raceable: eg replace seed between this stat and subsequent |
534 | * open. Not such a problem because we don't really trust the | |
40f64e6f | 535 | * seed file anyway. |
536 | * XXX: use secure path checking as elsewhere in OpenSSH | |
537 | */ | |
46058ce2 | 538 | if (lstat(filename, &st) == -1) { |
539 | /* Give up on hard errors */ | |
540 | if (errno != ENOENT) | |
40f64e6f | 541 | debug("WARNING: Couldn't stat random seed file " |
542 | "\"%.100s\": %s", filename, strerror(errno)); | |
543 | return 0; | |
46058ce2 | 544 | } |
545 | ||
546 | /* regular file? */ | |
547 | if (!S_ISREG(st.st_mode)) | |
40f64e6f | 548 | fatal("PRNG seedfile %.100s is not a regular file", |
549 | filename); | |
46058ce2 | 550 | |
551 | /* mode 0600, owned by root or the current user? */ | |
552 | if (((st.st_mode & 0177) != 0) || !(st.st_uid == getuid())) { | |
40f64e6f | 553 | debug("WARNING: PRNG seedfile %.100s must be mode 0600, " |
7be625e1 | 554 | "owned by uid %li", filename, (long int)getuid()); |
40f64e6f | 555 | return 0; |
46058ce2 | 556 | } |
557 | ||
40f64e6f | 558 | return 1; |
46058ce2 | 559 | } |
560 | ||
561 | void | |
40f64e6f | 562 | prng_write_seedfile(void) |
563 | { | |
a418076b | 564 | int fd, save_errno; |
75131bbd | 565 | unsigned char seed[SEED_FILE_SIZE]; |
a418076b | 566 | char filename[MAXPATHLEN], tmpseed[MAXPATHLEN]; |
46058ce2 | 567 | struct passwd *pw; |
a418076b | 568 | mode_t old_umask; |
46058ce2 | 569 | |
570 | pw = getpwuid(getuid()); | |
571 | if (pw == NULL) | |
40f64e6f | 572 | fatal("Couldn't get password entry for current user " |
7be625e1 | 573 | "(%li): %s", (long int)getuid(), strerror(errno)); |
46058ce2 | 574 | |
575 | /* Try to ensure that the parent directory is there */ | |
576 | snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir, | |
40f64e6f | 577 | _PATH_SSH_USER_DIR); |
46058ce2 | 578 | mkdir(filename, 0700); |
579 | ||
580 | snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir, | |
40f64e6f | 581 | SSH_PRNG_SEED_FILE); |
46058ce2 | 582 | |
a418076b | 583 | strlcpy(tmpseed, filename, sizeof(tmpseed)); |
584 | if (strlcat(tmpseed, ".XXXXXXXXXX", sizeof(tmpseed)) >= | |
585 | sizeof(tmpseed)) | |
586 | fatal("PRNG seed filename too long"); | |
46058ce2 | 587 | |
d8eb5247 | 588 | if (RAND_bytes(seed, sizeof(seed)) <= 0) |
9e3191db | 589 | fatal("PRNG seed extraction failed"); |
46058ce2 | 590 | |
591 | /* Don't care if the seed doesn't exist */ | |
592 | prng_check_seedfile(filename); | |
593 | ||
a418076b | 594 | old_umask = umask(0177); |
595 | ||
596 | if ((fd = mkstemp(tmpseed)) == -1) { | |
597 | debug("WARNING: couldn't make temporary PRNG seedfile %.100s " | |
598 | "(%.100s)", tmpseed, strerror(errno)); | |
46058ce2 | 599 | } else { |
a418076b | 600 | debug("writing PRNG seed to file %.100s", tmpseed); |
601 | if (atomicio(vwrite, fd, &seed, sizeof(seed)) < sizeof(seed)) { | |
602 | save_errno = errno; | |
603 | close(fd); | |
604 | unlink(tmpseed); | |
40f64e6f | 605 | fatal("problem writing PRNG seedfile %.100s " |
a418076b | 606 | "(%.100s)", filename, strerror(save_errno)); |
607 | } | |
46058ce2 | 608 | close(fd); |
a418076b | 609 | debug("moving temporary PRNG seed to file %.100s", filename); |
610 | if (rename(tmpseed, filename) == -1) { | |
611 | save_errno = errno; | |
612 | unlink(tmpseed); | |
613 | fatal("problem renaming PRNG seedfile from %.100s " | |
d1cf9a87 | 614 | "to %.100s (%.100s)", tmpseed, filename, |
a418076b | 615 | strerror(save_errno)); |
616 | } | |
46058ce2 | 617 | } |
a418076b | 618 | umask(old_umask); |
46058ce2 | 619 | } |
620 | ||
621 | void | |
40f64e6f | 622 | prng_read_seedfile(void) |
623 | { | |
46058ce2 | 624 | int fd; |
40f64e6f | 625 | char seed[SEED_FILE_SIZE], filename[MAXPATHLEN]; |
46058ce2 | 626 | struct passwd *pw; |
627 | ||
628 | pw = getpwuid(getuid()); | |
629 | if (pw == NULL) | |
40f64e6f | 630 | fatal("Couldn't get password entry for current user " |
7be625e1 | 631 | "(%li): %s", (long int)getuid(), strerror(errno)); |
46058ce2 | 632 | |
633 | snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir, | |
634 | SSH_PRNG_SEED_FILE); | |
635 | ||
636 | debug("loading PRNG seed from file %.100s", filename); | |
637 | ||
638 | if (!prng_check_seedfile(filename)) { | |
40f64e6f | 639 | verbose("Random seed file not found or invalid, ignoring."); |
46058ce2 | 640 | return; |
641 | } | |
642 | ||
643 | /* open the file and read in the seed */ | |
644 | fd = open(filename, O_RDONLY); | |
645 | if (fd == -1) | |
40f64e6f | 646 | fatal("could not open PRNG seedfile %.100s (%.100s)", |
647 | filename, strerror(errno)); | |
46058ce2 | 648 | |
40f64e6f | 649 | if (atomicio(read, fd, &seed, sizeof(seed)) < sizeof(seed)) { |
650 | verbose("invalid or short read from PRNG seedfile " | |
651 | "%.100s - ignoring", filename); | |
46058ce2 | 652 | memset(seed, '\0', sizeof(seed)); |
653 | } | |
654 | close(fd); | |
655 | ||
656 | /* stir in the seed, with estimated entropy zero */ | |
657 | RAND_add(&seed, sizeof(seed), 0.0); | |
658 | } | |
659 | ||
660 | ||
661 | /* | |
662 | * entropy command initialisation functions | |
663 | */ | |
664 | int | |
665 | prng_read_commands(char *cmdfilename) | |
666 | { | |
40f64e6f | 667 | char cmd[SEED_FILE_SIZE], *cp, line[1024], path[SEED_FILE_SIZE]; |
46058ce2 | 668 | double est; |
40f64e6f | 669 | entropy_cmd_t *entcmd; |
670 | FILE *f; | |
671 | int cur_cmd, linenum, num_cmds, arg; | |
46058ce2 | 672 | |
40f64e6f | 673 | if ((f = fopen(cmdfilename, "r")) == NULL) { |
46058ce2 | 674 | fatal("couldn't read entropy commands file %.100s: %.100s", |
675 | cmdfilename, strerror(errno)); | |
676 | } | |
677 | ||
40f64e6f | 678 | num_cmds = 64; |
679 | entcmd = xmalloc(num_cmds * sizeof(entropy_cmd_t)); | |
680 | memset(entcmd, '\0', num_cmds * sizeof(entropy_cmd_t)); | |
46058ce2 | 681 | |
682 | /* Read in file */ | |
40f64e6f | 683 | cur_cmd = linenum = 0; |
46058ce2 | 684 | while (fgets(line, sizeof(line), f)) { |
46058ce2 | 685 | linenum++; |
686 | ||
40f64e6f | 687 | /* Skip leading whitespace, blank lines and comments */ |
46058ce2 | 688 | cp = line + strspn(line, WHITESPACE); |
689 | if ((*cp == 0) || (*cp == '#')) | |
690 | continue; /* done with this line */ | |
691 | ||
40f64e6f | 692 | /* |
aff51935 | 693 | * The first non-whitespace char should be a double quote |
40f64e6f | 694 | * delimiting the commandline |
695 | */ | |
46058ce2 | 696 | if (*cp != '"') { |
40f64e6f | 697 | error("bad entropy command, %.100s line %d", |
698 | cmdfilename, linenum); | |
46058ce2 | 699 | continue; |
700 | } | |
701 | ||
40f64e6f | 702 | /* |
703 | * First token, command args (incl. argv[0]) in double | |
704 | * quotes | |
705 | */ | |
46058ce2 | 706 | cp = strtok(cp, "\""); |
707 | if (cp == NULL) { | |
40f64e6f | 708 | error("missing or bad command string, %.100s " |
709 | "line %d -- ignored", cmdfilename, linenum); | |
46058ce2 | 710 | continue; |
711 | } | |
712 | strlcpy(cmd, cp, sizeof(cmd)); | |
713 | ||
40f64e6f | 714 | /* Second token, full command path */ |
46058ce2 | 715 | if ((cp = strtok(NULL, WHITESPACE)) == NULL) { |
40f64e6f | 716 | error("missing command path, %.100s " |
717 | "line %d -- ignored", cmdfilename, linenum); | |
46058ce2 | 718 | continue; |
719 | } | |
720 | ||
40f64e6f | 721 | /* Did configure mark this as dead? */ |
46058ce2 | 722 | if (strncmp("undef", cp, 5) == 0) |
723 | continue; | |
724 | ||
725 | strlcpy(path, cp, sizeof(path)); | |
726 | ||
40f64e6f | 727 | /* Third token, entropy rate estimate for this command */ |
46058ce2 | 728 | if ((cp = strtok(NULL, WHITESPACE)) == NULL) { |
40f64e6f | 729 | error("missing entropy estimate, %.100s " |
730 | "line %d -- ignored", cmdfilename, linenum); | |
46058ce2 | 731 | continue; |
732 | } | |
40f64e6f | 733 | est = strtod(cp, NULL); |
46058ce2 | 734 | |
735 | /* end of line */ | |
736 | if ((cp = strtok(NULL, WHITESPACE)) != NULL) { | |
40f64e6f | 737 | error("garbage at end of line %d in %.100s " |
738 | "-- ignored", linenum, cmdfilename); | |
46058ce2 | 739 | continue; |
740 | } | |
741 | ||
742 | /* save the command for debug messages */ | |
743 | entcmd[cur_cmd].cmdstring = xstrdup(cmd); | |
744 | ||
745 | /* split the command args */ | |
746 | cp = strtok(cmd, WHITESPACE); | |
747 | arg = 0; | |
46058ce2 | 748 | do { |
40f64e6f | 749 | entcmd[cur_cmd].args[arg] = xstrdup(cp); |
46058ce2 | 750 | arg++; |
40f64e6f | 751 | } while(arg < NUM_ARGS && (cp = strtok(NULL, WHITESPACE))); |
46058ce2 | 752 | |
753 | if (strtok(NULL, WHITESPACE)) | |
40f64e6f | 754 | error("ignored extra commands (max %d), %.100s " |
755 | "line %d", NUM_ARGS, cmdfilename, linenum); | |
46058ce2 | 756 | |
757 | /* Copy the command path and rate estimate */ | |
758 | entcmd[cur_cmd].path = xstrdup(path); | |
759 | entcmd[cur_cmd].rate = est; | |
760 | ||
761 | /* Initialise other values */ | |
762 | entcmd[cur_cmd].sticky_badness = 1; | |
763 | ||
764 | cur_cmd++; | |
765 | ||
40f64e6f | 766 | /* |
767 | * If we've filled the array, reallocate it twice the size | |
aff51935 | 768 | * Do this now because even if this we're on the last |
40f64e6f | 769 | * command we need another slot to mark the last entry |
770 | */ | |
46058ce2 | 771 | if (cur_cmd == num_cmds) { |
772 | num_cmds *= 2; | |
40f64e6f | 773 | entcmd = xrealloc(entcmd, num_cmds * |
774 | sizeof(entropy_cmd_t)); | |
46058ce2 | 775 | } |
776 | } | |
777 | ||
778 | /* zero the last entry */ | |
40f64e6f | 779 | memset(&entcmd[cur_cmd], '\0', sizeof(entropy_cmd_t)); |
46058ce2 | 780 | |
781 | /* trim to size */ | |
40f64e6f | 782 | entropy_cmds = xrealloc(entcmd, (cur_cmd + 1) * |
783 | sizeof(entropy_cmd_t)); | |
46058ce2 | 784 | |
40f64e6f | 785 | debug("Loaded %d entropy commands from %.100s", cur_cmd, |
786 | cmdfilename); | |
46058ce2 | 787 | |
40f64e6f | 788 | return cur_cmd < MIN_ENTROPY_SOURCES ? -1 : 0; |
46058ce2 | 789 | } |
790 | ||
f6e6303d | 791 | void |
792 | usage(void) | |
793 | { | |
794 | fprintf(stderr, "Usage: %s [options]\n", __progname); | |
795 | fprintf(stderr, " -v Verbose; display verbose debugging messages.\n"); | |
796 | fprintf(stderr, " Multiple -v increases verbosity.\n"); | |
96b0de7d | 797 | fprintf(stderr, " -x Force output in hexadecimal (for debugging)\n"); |
f6e6303d | 798 | fprintf(stderr, " -X Force output in binary\n"); |
799 | fprintf(stderr, " -b bytes Number of bytes to output (default %d)\n", | |
800 | OUTPUT_SEED_SIZE); | |
801 | } | |
802 | ||
aff51935 | 803 | int |
46058ce2 | 804 | main(int argc, char **argv) |
805 | { | |
f6e6303d | 806 | unsigned char *buf; |
807 | int ret, ch, debug_level, output_hex, bytes; | |
808 | extern char *optarg; | |
809 | LogLevel ll; | |
46058ce2 | 810 | |
fda04d7d | 811 | __progname = ssh_get_progname(argv[0]); |
46058ce2 | 812 | log_init(argv[0], SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_USER, 1); |
813 | ||
f6e6303d | 814 | ll = SYSLOG_LEVEL_INFO; |
815 | debug_level = output_hex = 0; | |
816 | bytes = OUTPUT_SEED_SIZE; | |
817 | ||
818 | /* Don't write binary data to a tty, unless we are forced to */ | |
819 | if (isatty(STDOUT_FILENO)) | |
820 | output_hex = 1; | |
b6453d99 | 821 | |
f6e6303d | 822 | while ((ch = getopt(argc, argv, "vxXhb:")) != -1) { |
823 | switch (ch) { | |
824 | case 'v': | |
825 | if (debug_level < 3) | |
826 | ll = SYSLOG_LEVEL_DEBUG1 + debug_level++; | |
827 | break; | |
828 | case 'x': | |
829 | output_hex = 1; | |
830 | break; | |
831 | case 'X': | |
832 | output_hex = 0; | |
833 | break; | |
834 | case 'b': | |
835 | if ((bytes = atoi(optarg)) <= 0) | |
836 | fatal("Invalid number of output bytes"); | |
837 | break; | |
838 | case 'h': | |
839 | usage(); | |
840 | exit(0); | |
841 | default: | |
842 | error("Invalid commandline option"); | |
843 | usage(); | |
844 | } | |
845 | } | |
846 | ||
847 | log_init(argv[0], ll, SYSLOG_FACILITY_USER, 1); | |
b6453d99 | 848 | |
40f64e6f | 849 | #ifdef USE_SEED_FILES |
850 | prng_read_seedfile(); | |
851 | #endif | |
852 | ||
f6e6303d | 853 | buf = xmalloc(bytes); |
854 | ||
40f64e6f | 855 | /* |
856 | * Seed the RNG from wherever we can | |
857 | */ | |
b6453d99 | 858 | |
40f64e6f | 859 | /* Take whatever is on the stack, but don't credit it */ |
f6e6303d | 860 | RAND_add(buf, bytes, 0); |
40f64e6f | 861 | |
aff51935 | 862 | debug("Seeded RNG with %i bytes from system calls", |
40f64e6f | 863 | (int)stir_from_system()); |
864 | ||
1e111f05 | 865 | /* try prngd, fall back to commands if prngd fails or not configured */ |
866 | if (seed_from_prngd(buf, bytes) == 0) { | |
867 | RAND_add(buf, bytes, bytes); | |
868 | } else { | |
869 | /* Read in collection commands */ | |
870 | if (prng_read_commands(SSH_PRNG_COMMAND_FILE) == -1) | |
871 | fatal("PRNG initialisation failed -- exiting."); | |
872 | debug("Seeded RNG with %i bytes from programs", | |
873 | (int)stir_from_programs()); | |
874 | } | |
40f64e6f | 875 | |
876 | #ifdef USE_SEED_FILES | |
877 | prng_write_seedfile(); | |
878 | #endif | |
879 | ||
880 | /* | |
881 | * Write the seed to stdout | |
882 | */ | |
46058ce2 | 883 | |
884 | if (!RAND_status()) | |
885 | fatal("Not enough entropy in RNG"); | |
886 | ||
d8eb5247 | 887 | if (RAND_bytes(buf, bytes) <= 0) |
888 | fatal("Couldn't extract entropy from PRNG"); | |
46058ce2 | 889 | |
f6e6303d | 890 | if (output_hex) { |
891 | for(ret = 0; ret < bytes; ret++) | |
892 | printf("%02x", (unsigned char)(buf[ret])); | |
893 | printf("\n"); | |
894 | } else | |
d72f7b79 | 895 | ret = atomicio(vwrite, STDOUT_FILENO, buf, bytes); |
b6453d99 | 896 | |
f6e6303d | 897 | memset(buf, '\0', bytes); |
898 | xfree(buf); | |
b6453d99 | 899 | |
f6e6303d | 900 | return ret == bytes ? 0 : 1; |
46058ce2 | 901 | } |
e005a96c | 902 | |
903 | /* | |
904 | * We may attempt to re-seed during mkstemp if we are using the one in the | |
759c7b91 | 905 | * compat library (via mkstemp -> _gettemp -> arc4random -> seed_rng) so we |
906 | * need our own seed_rng(). We must also check that we have enough entropy. | |
e005a96c | 907 | */ |
908 | void | |
909 | seed_rng(void) | |
910 | { | |
911 | if (!RAND_status()) | |
912 | fatal("Not enough entropy in RNG"); | |
913 | } |