]>
Commit | Line | Data |
---|---|---|
d832c38e | 1 | /* |
2 | * Copyright (c) 2001-2002 Damien Miller. All rights reserved. | |
3 | * | |
4 | * Redistribution and use in source and binary forms, with or without | |
5 | * modification, are permitted provided that the following conditions | |
6 | * are met: | |
7 | * 1. Redistributions of source code must retain the above copyright | |
8 | * notice, this list of conditions and the following disclaimer. | |
9 | * 2. Redistributions in binary form must reproduce the above copyright | |
10 | * notice, this list of conditions and the following disclaimer in the | |
11 | * documentation and/or other materials provided with the distribution. | |
12 | * | |
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 | ||
30460aeb | 27 | #include <sys/types.h> |
28 | #include <sys/resource.h> | |
29 | #include <sys/stat.h> | |
30 | #include <sys/wait.h> | |
31 | #include <sys/socket.h> | |
32 | ||
33 | #include <stdarg.h> | |
34 | #include <stddef.h> | |
fa0f0f45 | 35 | #include <string.h> |
30460aeb | 36 | |
37 | #include <netinet/in.h> | |
38 | #include <arpa/inet.h> | |
39 | ||
40 | #ifdef HAVE_SYS_UN_H | |
41 | # include <sys/un.h> | |
42 | #endif | |
43 | ||
44 | #include <errno.h> | |
45 | #include <fcntl.h> | |
46 | #include <pwd.h> | |
47 | #include <signal.h> | |
48 | #include <time.h> | |
49 | #include <unistd.h> | |
50 | ||
d832c38e | 51 | #include <openssl/rand.h> |
52 | #include <openssl/sha.h> | |
53 | #include <openssl/crypto.h> | |
54 | ||
55 | /* SunOS 4.4.4 needs this */ | |
56 | #ifdef HAVE_FLOATINGPOINT_H | |
57 | # include <floatingpoint.h> | |
58 | #endif /* HAVE_FLOATINGPOINT_H */ | |
59 | ||
60 | #include "misc.h" | |
61 | #include "xmalloc.h" | |
62 | #include "atomicio.h" | |
63 | #include "pathnames.h" | |
64 | #include "log.h" | |
65 | ||
d832c38e | 66 | /* Number of bytes we write out */ |
67 | #define OUTPUT_SEED_SIZE 48 | |
68 | ||
69 | /* Length of on-disk seedfiles */ | |
70 | #define SEED_FILE_SIZE 1024 | |
71 | ||
72 | /* Maximum number of command-line arguments to read from file */ | |
73 | #define NUM_ARGS 10 | |
74 | ||
75 | /* Minimum number of usable commands to be considered sufficient */ | |
76 | #define MIN_ENTROPY_SOURCES 16 | |
77 | ||
78 | /* Path to on-disk seed file (relative to user's home directory */ | |
79 | #ifndef SSH_PRNG_SEED_FILE | |
80 | # define SSH_PRNG_SEED_FILE _PATH_SSH_USER_DIR"/prng_seed" | |
81 | #endif | |
82 | ||
83 | /* Path to PRNG commands list */ | |
84 | #ifndef SSH_PRNG_COMMAND_FILE | |
85 | # define SSH_PRNG_COMMAND_FILE SSHDIR "/ssh_prng_cmds" | |
86 | #endif | |
87 | ||
d832c38e | 88 | extern char *__progname; |
d832c38e | 89 | |
90 | #define WHITESPACE " \t\n" | |
91 | ||
92 | #ifndef RUSAGE_SELF | |
93 | # define RUSAGE_SELF 0 | |
94 | #endif | |
95 | #ifndef RUSAGE_CHILDREN | |
96 | # define RUSAGE_CHILDREN 0 | |
97 | #endif | |
98 | ||
99 | #if !defined(PRNGD_SOCKET) && !defined(PRNGD_PORT) | |
100 | # define USE_SEED_FILES | |
101 | #endif | |
102 | ||
103 | typedef struct { | |
104 | /* Proportion of data that is entropy */ | |
105 | double rate; | |
106 | /* Counter goes positive if this command times out */ | |
107 | unsigned int badness; | |
108 | /* Increases by factor of two each timeout */ | |
109 | unsigned int sticky_badness; | |
110 | /* Path to executable */ | |
111 | char *path; | |
112 | /* argv to pass to executable */ | |
113 | char *args[NUM_ARGS]; /* XXX: arbitrary limit */ | |
114 | /* full command string (debug) */ | |
115 | char *cmdstring; | |
116 | } entropy_cmd_t; | |
117 | ||
118 | /* slow command timeouts (all in milliseconds) */ | |
119 | /* static int entropy_timeout_default = ENTROPY_TIMEOUT_MSEC; */ | |
120 | static int entropy_timeout_current = ENTROPY_TIMEOUT_MSEC; | |
121 | ||
122 | /* this is initialised from a file, by prng_read_commands() */ | |
123 | static entropy_cmd_t *entropy_cmds = NULL; | |
124 | ||
125 | /* Prototypes */ | |
126 | double stir_from_system(void); | |
127 | double stir_from_programs(void); | |
128 | double stir_gettimeofday(double entropy_estimate); | |
129 | double stir_clock(double entropy_estimate); | |
130 | double stir_rusage(int who, double entropy_estimate); | |
d03f4262 | 131 | double hash_command_output(entropy_cmd_t *src, unsigned char *hash); |
540d72c3 | 132 | int get_random_bytes_prngd(unsigned char *buf, int len, |
d832c38e | 133 | unsigned short tcp_port, char *socket_path); |
134 | ||
135 | /* | |
136 | * Collect 'len' bytes of entropy into 'buf' from PRNGD/EGD daemon | |
137 | * listening either on 'tcp_port', or via Unix domain socket at * | |
138 | * 'socket_path'. | |
540d72c3 | 139 | * Either a non-zero tcp_port or a non-null socket_path must be |
d832c38e | 140 | * supplied. |
141 | * Returns 0 on success, -1 on error | |
142 | */ | |
143 | int | |
540d72c3 | 144 | get_random_bytes_prngd(unsigned char *buf, int len, |
d832c38e | 145 | unsigned short tcp_port, char *socket_path) |
146 | { | |
147 | int fd, addr_len, rval, errors; | |
2ce0bfe4 | 148 | u_char msg[2]; |
d832c38e | 149 | struct sockaddr_storage addr; |
150 | struct sockaddr_in *addr_in = (struct sockaddr_in *)&addr; | |
151 | struct sockaddr_un *addr_un = (struct sockaddr_un *)&addr; | |
152 | mysig_t old_sigpipe; | |
153 | ||
154 | /* Sanity checks */ | |
155 | if (socket_path == NULL && tcp_port == 0) | |
156 | fatal("You must specify a port or a socket"); | |
157 | if (socket_path != NULL && | |
158 | strlen(socket_path) >= sizeof(addr_un->sun_path)) | |
159 | fatal("Random pool path is too long"); | |
2ce0bfe4 | 160 | if (len <= 0 || len > 255) |
161 | fatal("Too many bytes (%d) to read from PRNGD", len); | |
d832c38e | 162 | |
163 | memset(&addr, '\0', sizeof(addr)); | |
164 | ||
165 | if (tcp_port != 0) { | |
166 | addr_in->sin_family = AF_INET; | |
167 | addr_in->sin_addr.s_addr = htonl(INADDR_LOOPBACK); | |
168 | addr_in->sin_port = htons(tcp_port); | |
169 | addr_len = sizeof(*addr_in); | |
170 | } else { | |
171 | addr_un->sun_family = AF_UNIX; | |
172 | strlcpy(addr_un->sun_path, socket_path, | |
173 | sizeof(addr_un->sun_path)); | |
174 | addr_len = offsetof(struct sockaddr_un, sun_path) + | |
175 | strlen(socket_path) + 1; | |
176 | } | |
177 | ||
178 | old_sigpipe = mysignal(SIGPIPE, SIG_IGN); | |
179 | ||
180 | errors = 0; | |
181 | rval = -1; | |
182 | reopen: | |
183 | fd = socket(addr.ss_family, SOCK_STREAM, 0); | |
184 | if (fd == -1) { | |
185 | error("Couldn't create socket: %s", strerror(errno)); | |
186 | goto done; | |
187 | } | |
188 | ||
189 | if (connect(fd, (struct sockaddr*)&addr, addr_len) == -1) { | |
190 | if (tcp_port != 0) { | |
191 | error("Couldn't connect to PRNGD port %d: %s", | |
192 | tcp_port, strerror(errno)); | |
193 | } else { | |
194 | error("Couldn't connect to PRNGD socket \"%s\": %s", | |
195 | addr_un->sun_path, strerror(errno)); | |
196 | } | |
197 | goto done; | |
198 | } | |
199 | ||
200 | /* Send blocking read request to PRNGD */ | |
201 | msg[0] = 0x02; | |
202 | msg[1] = len; | |
203 | ||
7cac2b65 | 204 | if (atomicio(vwrite, fd, msg, sizeof(msg)) != sizeof(msg)) { |
d832c38e | 205 | if (errno == EPIPE && errors < 10) { |
206 | close(fd); | |
207 | errors++; | |
208 | goto reopen; | |
209 | } | |
210 | error("Couldn't write to PRNGD socket: %s", | |
211 | strerror(errno)); | |
212 | goto done; | |
213 | } | |
214 | ||
2ce0bfe4 | 215 | if (atomicio(read, fd, buf, len) != (size_t)len) { |
d832c38e | 216 | if (errno == EPIPE && errors < 10) { |
217 | close(fd); | |
218 | errors++; | |
219 | goto reopen; | |
220 | } | |
221 | error("Couldn't read from PRNGD socket: %s", | |
222 | strerror(errno)); | |
223 | goto done; | |
224 | } | |
225 | ||
226 | rval = 0; | |
227 | done: | |
228 | mysignal(SIGPIPE, old_sigpipe); | |
229 | if (fd != -1) | |
230 | close(fd); | |
231 | return rval; | |
232 | } | |
233 | ||
dfddba3d | 234 | static int |
235 | seed_from_prngd(unsigned char *buf, size_t bytes) | |
236 | { | |
237 | #ifdef PRNGD_PORT | |
238 | debug("trying egd/prngd port %d", PRNGD_PORT); | |
239 | if (get_random_bytes_prngd(buf, bytes, PRNGD_PORT, NULL) == 0) | |
240 | return 0; | |
241 | #endif | |
242 | #ifdef PRNGD_SOCKET | |
243 | debug("trying egd/prngd socket %s", PRNGD_SOCKET); | |
244 | if (get_random_bytes_prngd(buf, bytes, 0, PRNGD_SOCKET) == 0) | |
245 | return 0; | |
246 | #endif | |
247 | return -1; | |
248 | } | |
249 | ||
d832c38e | 250 | double |
251 | stir_gettimeofday(double entropy_estimate) | |
252 | { | |
253 | struct timeval tv; | |
254 | ||
255 | if (gettimeofday(&tv, NULL) == -1) | |
256 | fatal("Couldn't gettimeofday: %s", strerror(errno)); | |
257 | ||
258 | RAND_add(&tv, sizeof(tv), entropy_estimate); | |
259 | ||
260 | return entropy_estimate; | |
261 | } | |
262 | ||
263 | double | |
264 | stir_clock(double entropy_estimate) | |
265 | { | |
266 | #ifdef HAVE_CLOCK | |
267 | clock_t c; | |
268 | ||
269 | c = clock(); | |
270 | RAND_add(&c, sizeof(c), entropy_estimate); | |
271 | ||
272 | return entropy_estimate; | |
273 | #else /* _HAVE_CLOCK */ | |
274 | return 0; | |
275 | #endif /* _HAVE_CLOCK */ | |
276 | } | |
277 | ||
278 | double | |
279 | stir_rusage(int who, double entropy_estimate) | |
280 | { | |
281 | #ifdef HAVE_GETRUSAGE | |
282 | struct rusage ru; | |
283 | ||
284 | if (getrusage(who, &ru) == -1) | |
285 | return 0; | |
286 | ||
287 | RAND_add(&ru, sizeof(ru), entropy_estimate); | |
288 | ||
289 | return entropy_estimate; | |
290 | #else /* _HAVE_GETRUSAGE */ | |
291 | return 0; | |
292 | #endif /* _HAVE_GETRUSAGE */ | |
293 | } | |
294 | ||
295 | static int | |
296 | timeval_diff(struct timeval *t1, struct timeval *t2) | |
297 | { | |
298 | int secdiff, usecdiff; | |
299 | ||
300 | secdiff = t2->tv_sec - t1->tv_sec; | |
301 | usecdiff = (secdiff*1000000) + (t2->tv_usec - t1->tv_usec); | |
302 | return (int)(usecdiff / 1000); | |
303 | } | |
304 | ||
305 | double | |
d03f4262 | 306 | hash_command_output(entropy_cmd_t *src, unsigned char *hash) |
d832c38e | 307 | { |
308 | char buf[8192]; | |
309 | fd_set rdset; | |
310 | int bytes_read, cmd_eof, error_abort, msec_elapsed, p[2]; | |
311 | int status, total_bytes_read; | |
312 | static int devnull = -1; | |
313 | pid_t pid; | |
314 | SHA_CTX sha; | |
315 | struct timeval tv_start, tv_current; | |
316 | ||
317 | debug3("Reading output from \'%s\'", src->cmdstring); | |
318 | ||
319 | if (devnull == -1) { | |
320 | devnull = open("/dev/null", O_RDWR); | |
321 | if (devnull == -1) | |
540d72c3 | 322 | fatal("Couldn't open /dev/null: %s", |
d832c38e | 323 | strerror(errno)); |
324 | } | |
325 | ||
326 | if (pipe(p) == -1) | |
327 | fatal("Couldn't open pipe: %s", strerror(errno)); | |
328 | ||
329 | (void)gettimeofday(&tv_start, NULL); /* record start time */ | |
330 | ||
331 | switch (pid = fork()) { | |
332 | case -1: /* Error */ | |
333 | close(p[0]); | |
334 | close(p[1]); | |
335 | fatal("Couldn't fork: %s", strerror(errno)); | |
336 | /* NOTREACHED */ | |
337 | case 0: /* Child */ | |
338 | dup2(devnull, STDIN_FILENO); | |
339 | dup2(p[1], STDOUT_FILENO); | |
340 | dup2(p[1], STDERR_FILENO); | |
341 | close(p[0]); | |
342 | close(p[1]); | |
343 | close(devnull); | |
344 | ||
345 | execv(src->path, (char**)(src->args)); | |
346 | ||
540d72c3 | 347 | debug("(child) Couldn't exec '%s': %s", |
d832c38e | 348 | src->cmdstring, strerror(errno)); |
349 | _exit(-1); | |
350 | default: /* Parent */ | |
351 | break; | |
352 | } | |
353 | ||
354 | RAND_add(&pid, sizeof(&pid), 0.0); | |
355 | ||
356 | close(p[1]); | |
357 | ||
358 | /* Hash output from child */ | |
359 | SHA1_Init(&sha); | |
360 | ||
361 | cmd_eof = error_abort = msec_elapsed = total_bytes_read = 0; | |
362 | while (!error_abort && !cmd_eof) { | |
363 | int ret; | |
364 | struct timeval tv; | |
365 | int msec_remaining; | |
366 | ||
367 | (void) gettimeofday(&tv_current, 0); | |
368 | msec_elapsed = timeval_diff(&tv_start, &tv_current); | |
369 | if (msec_elapsed >= entropy_timeout_current) { | |
370 | error_abort=1; | |
371 | continue; | |
372 | } | |
373 | msec_remaining = entropy_timeout_current - msec_elapsed; | |
374 | ||
375 | FD_ZERO(&rdset); | |
376 | FD_SET(p[0], &rdset); | |
377 | tv.tv_sec = msec_remaining / 1000; | |
378 | tv.tv_usec = (msec_remaining % 1000) * 1000; | |
379 | ||
380 | ret = select(p[0] + 1, &rdset, NULL, NULL, &tv); | |
381 | ||
382 | RAND_add(&tv, sizeof(tv), 0.0); | |
383 | ||
384 | switch (ret) { | |
385 | case 0: | |
386 | /* timer expired */ | |
387 | error_abort = 1; | |
bfe49944 | 388 | kill(pid, SIGINT); |
d832c38e | 389 | break; |
390 | case 1: | |
391 | /* command input */ | |
392 | do { | |
393 | bytes_read = read(p[0], buf, sizeof(buf)); | |
394 | } while (bytes_read == -1 && errno == EINTR); | |
395 | RAND_add(&bytes_read, sizeof(&bytes_read), 0.0); | |
396 | if (bytes_read == -1) { | |
397 | error_abort = 1; | |
398 | break; | |
399 | } else if (bytes_read) { | |
400 | SHA1_Update(&sha, buf, bytes_read); | |
401 | total_bytes_read += bytes_read; | |
402 | } else { | |
403 | cmd_eof = 1; | |
404 | } | |
405 | break; | |
406 | case -1: | |
407 | default: | |
408 | /* error */ | |
540d72c3 | 409 | debug("Command '%s': select() failed: %s", |
d832c38e | 410 | src->cmdstring, strerror(errno)); |
411 | error_abort = 1; | |
412 | break; | |
413 | } | |
414 | } | |
415 | ||
416 | SHA1_Final(hash, &sha); | |
417 | ||
418 | close(p[0]); | |
419 | ||
420 | debug3("Time elapsed: %d msec", msec_elapsed); | |
421 | ||
422 | if (waitpid(pid, &status, 0) == -1) { | |
2ce0bfe4 | 423 | error("Couldn't wait for child '%s' completion: %s", |
424 | src->cmdstring, strerror(errno)); | |
d832c38e | 425 | return 0.0; |
426 | } | |
427 | ||
428 | RAND_add(&status, sizeof(&status), 0.0); | |
429 | ||
430 | if (error_abort) { | |
431 | /* | |
432 | * Closing p[0] on timeout causes the entropy command to | |
540d72c3 | 433 | * SIGPIPE. Take whatever output we got, and mark this |
434 | * command as slow | |
d832c38e | 435 | */ |
436 | debug2("Command '%s' timed out", src->cmdstring); | |
437 | src->sticky_badness *= 2; | |
438 | src->badness = src->sticky_badness; | |
439 | return total_bytes_read; | |
440 | } | |
441 | ||
442 | if (WIFEXITED(status)) { | |
443 | if (WEXITSTATUS(status) == 0) { | |
444 | return total_bytes_read; | |
445 | } else { | |
446 | debug2("Command '%s' exit status was %d", | |
447 | src->cmdstring, WEXITSTATUS(status)); | |
448 | src->badness = src->sticky_badness = 128; | |
449 | return 0.0; | |
450 | } | |
451 | } else if (WIFSIGNALED(status)) { | |
452 | debug2("Command '%s' returned on uncaught signal %d !", | |
453 | src->cmdstring, status); | |
454 | src->badness = src->sticky_badness = 128; | |
455 | return 0.0; | |
456 | } else | |
457 | return 0.0; | |
458 | } | |
459 | ||
460 | double | |
461 | stir_from_system(void) | |
462 | { | |
463 | double total_entropy_estimate; | |
464 | long int i; | |
465 | ||
466 | total_entropy_estimate = 0; | |
467 | ||
468 | i = getpid(); | |
469 | RAND_add(&i, sizeof(i), 0.5); | |
470 | total_entropy_estimate += 0.1; | |
471 | ||
472 | i = getppid(); | |
473 | RAND_add(&i, sizeof(i), 0.5); | |
474 | total_entropy_estimate += 0.1; | |
475 | ||
476 | i = getuid(); | |
477 | RAND_add(&i, sizeof(i), 0.0); | |
478 | i = getgid(); | |
479 | RAND_add(&i, sizeof(i), 0.0); | |
480 | ||
481 | total_entropy_estimate += stir_gettimeofday(1.0); | |
482 | total_entropy_estimate += stir_clock(0.5); | |
483 | total_entropy_estimate += stir_rusage(RUSAGE_SELF, 2.0); | |
484 | ||
485 | return total_entropy_estimate; | |
486 | } | |
487 | ||
488 | double | |
489 | stir_from_programs(void) | |
490 | { | |
491 | int c; | |
492 | double entropy, total_entropy; | |
d03f4262 | 493 | unsigned char hash[SHA_DIGEST_LENGTH]; |
d832c38e | 494 | |
495 | total_entropy = 0; | |
496 | for(c = 0; entropy_cmds[c].path != NULL; c++) { | |
497 | if (!entropy_cmds[c].badness) { | |
498 | /* Hash output from command */ | |
499 | entropy = hash_command_output(&entropy_cmds[c], | |
500 | hash); | |
501 | ||
502 | /* Scale back estimate by command's rate */ | |
503 | entropy *= entropy_cmds[c].rate; | |
504 | ||
505 | /* Upper bound of entropy is SHA_DIGEST_LENGTH */ | |
506 | if (entropy > SHA_DIGEST_LENGTH) | |
507 | entropy = SHA_DIGEST_LENGTH; | |
508 | ||
509 | /* Stir it in */ | |
510 | RAND_add(hash, sizeof(hash), entropy); | |
511 | ||
540d72c3 | 512 | debug3("Got %0.2f bytes of entropy from '%s'", |
d832c38e | 513 | entropy, entropy_cmds[c].cmdstring); |
514 | ||
515 | total_entropy += entropy; | |
516 | ||
517 | /* Execution time should be a bit unpredictable */ | |
518 | total_entropy += stir_gettimeofday(0.05); | |
519 | total_entropy += stir_clock(0.05); | |
520 | total_entropy += stir_rusage(RUSAGE_SELF, 0.1); | |
521 | total_entropy += stir_rusage(RUSAGE_CHILDREN, 0.1); | |
522 | } else { | |
523 | debug2("Command '%s' disabled (badness %d)", | |
540d72c3 | 524 | entropy_cmds[c].cmdstring, |
d832c38e | 525 | entropy_cmds[c].badness); |
526 | ||
527 | if (entropy_cmds[c].badness > 0) | |
528 | entropy_cmds[c].badness--; | |
529 | } | |
530 | } | |
531 | ||
532 | return total_entropy; | |
533 | } | |
534 | ||
535 | /* | |
536 | * prng seedfile functions | |
537 | */ | |
538 | int | |
539 | prng_check_seedfile(char *filename) | |
540 | { | |
541 | struct stat st; | |
542 | ||
543 | /* | |
540d72c3 | 544 | * XXX raceable: eg replace seed between this stat and subsequent |
545 | * open. Not such a problem because we don't really trust the | |
d832c38e | 546 | * seed file anyway. |
547 | * XXX: use secure path checking as elsewhere in OpenSSH | |
548 | */ | |
549 | if (lstat(filename, &st) == -1) { | |
550 | /* Give up on hard errors */ | |
551 | if (errno != ENOENT) | |
552 | debug("WARNING: Couldn't stat random seed file " | |
553 | "\"%.100s\": %s", filename, strerror(errno)); | |
554 | return 0; | |
555 | } | |
556 | ||
557 | /* regular file? */ | |
558 | if (!S_ISREG(st.st_mode)) | |
559 | fatal("PRNG seedfile %.100s is not a regular file", | |
560 | filename); | |
561 | ||
562 | /* mode 0600, owned by root or the current user? */ | |
563 | if (((st.st_mode & 0177) != 0) || !(st.st_uid == getuid())) { | |
564 | debug("WARNING: PRNG seedfile %.100s must be mode 0600, " | |
7cac2b65 | 565 | "owned by uid %li", filename, (long int)getuid()); |
d832c38e | 566 | return 0; |
567 | } | |
568 | ||
569 | return 1; | |
570 | } | |
571 | ||
572 | void | |
573 | prng_write_seedfile(void) | |
574 | { | |
dfddba3d | 575 | int fd, save_errno; |
d03f4262 | 576 | unsigned char seed[SEED_FILE_SIZE]; |
dfddba3d | 577 | char filename[MAXPATHLEN], tmpseed[MAXPATHLEN]; |
d832c38e | 578 | struct passwd *pw; |
dfddba3d | 579 | mode_t old_umask; |
d832c38e | 580 | |
581 | pw = getpwuid(getuid()); | |
582 | if (pw == NULL) | |
583 | fatal("Couldn't get password entry for current user " | |
7cac2b65 | 584 | "(%li): %s", (long int)getuid(), strerror(errno)); |
d832c38e | 585 | |
586 | /* Try to ensure that the parent directory is there */ | |
587 | snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir, | |
588 | _PATH_SSH_USER_DIR); | |
30460aeb | 589 | if (mkdir(filename, 0700) < 0 && errno != EEXIST) |
590 | fatal("mkdir %.200s: %s", filename, strerror(errno)); | |
d832c38e | 591 | |
592 | snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir, | |
593 | SSH_PRNG_SEED_FILE); | |
594 | ||
dfddba3d | 595 | strlcpy(tmpseed, filename, sizeof(tmpseed)); |
596 | if (strlcat(tmpseed, ".XXXXXXXXXX", sizeof(tmpseed)) >= | |
597 | sizeof(tmpseed)) | |
598 | fatal("PRNG seed filename too long"); | |
d832c38e | 599 | |
bfe49944 | 600 | if (RAND_bytes(seed, sizeof(seed)) <= 0) |
540d72c3 | 601 | fatal("PRNG seed extraction failed"); |
d832c38e | 602 | |
603 | /* Don't care if the seed doesn't exist */ | |
604 | prng_check_seedfile(filename); | |
605 | ||
dfddba3d | 606 | old_umask = umask(0177); |
607 | ||
608 | if ((fd = mkstemp(tmpseed)) == -1) { | |
609 | debug("WARNING: couldn't make temporary PRNG seedfile %.100s " | |
610 | "(%.100s)", tmpseed, strerror(errno)); | |
d832c38e | 611 | } else { |
dfddba3d | 612 | debug("writing PRNG seed to file %.100s", tmpseed); |
613 | if (atomicio(vwrite, fd, &seed, sizeof(seed)) < sizeof(seed)) { | |
614 | save_errno = errno; | |
615 | close(fd); | |
616 | unlink(tmpseed); | |
d832c38e | 617 | fatal("problem writing PRNG seedfile %.100s " |
dfddba3d | 618 | "(%.100s)", filename, strerror(save_errno)); |
619 | } | |
d832c38e | 620 | close(fd); |
dfddba3d | 621 | debug("moving temporary PRNG seed to file %.100s", filename); |
622 | if (rename(tmpseed, filename) == -1) { | |
623 | save_errno = errno; | |
624 | unlink(tmpseed); | |
625 | fatal("problem renaming PRNG seedfile from %.100s " | |
2ce0bfe4 | 626 | "to %.100s (%.100s)", tmpseed, filename, |
dfddba3d | 627 | strerror(save_errno)); |
628 | } | |
d832c38e | 629 | } |
dfddba3d | 630 | umask(old_umask); |
d832c38e | 631 | } |
632 | ||
633 | void | |
634 | prng_read_seedfile(void) | |
635 | { | |
636 | int fd; | |
637 | char seed[SEED_FILE_SIZE], filename[MAXPATHLEN]; | |
638 | struct passwd *pw; | |
639 | ||
640 | pw = getpwuid(getuid()); | |
641 | if (pw == NULL) | |
642 | fatal("Couldn't get password entry for current user " | |
7cac2b65 | 643 | "(%li): %s", (long int)getuid(), strerror(errno)); |
d832c38e | 644 | |
645 | snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir, | |
646 | SSH_PRNG_SEED_FILE); | |
647 | ||
648 | debug("loading PRNG seed from file %.100s", filename); | |
649 | ||
650 | if (!prng_check_seedfile(filename)) { | |
651 | verbose("Random seed file not found or invalid, ignoring."); | |
652 | return; | |
653 | } | |
654 | ||
655 | /* open the file and read in the seed */ | |
656 | fd = open(filename, O_RDONLY); | |
657 | if (fd == -1) | |
658 | fatal("could not open PRNG seedfile %.100s (%.100s)", | |
659 | filename, strerror(errno)); | |
660 | ||
661 | if (atomicio(read, fd, &seed, sizeof(seed)) < sizeof(seed)) { | |
662 | verbose("invalid or short read from PRNG seedfile " | |
663 | "%.100s - ignoring", filename); | |
664 | memset(seed, '\0', sizeof(seed)); | |
665 | } | |
666 | close(fd); | |
667 | ||
668 | /* stir in the seed, with estimated entropy zero */ | |
669 | RAND_add(&seed, sizeof(seed), 0.0); | |
670 | } | |
671 | ||
672 | ||
673 | /* | |
674 | * entropy command initialisation functions | |
675 | */ | |
676 | int | |
677 | prng_read_commands(char *cmdfilename) | |
678 | { | |
679 | char cmd[SEED_FILE_SIZE], *cp, line[1024], path[SEED_FILE_SIZE]; | |
680 | double est; | |
681 | entropy_cmd_t *entcmd; | |
682 | FILE *f; | |
683 | int cur_cmd, linenum, num_cmds, arg; | |
684 | ||
685 | if ((f = fopen(cmdfilename, "r")) == NULL) { | |
686 | fatal("couldn't read entropy commands file %.100s: %.100s", | |
687 | cmdfilename, strerror(errno)); | |
688 | } | |
689 | ||
690 | num_cmds = 64; | |
30460aeb | 691 | entcmd = xcalloc(num_cmds, sizeof(entropy_cmd_t)); |
d832c38e | 692 | |
693 | /* Read in file */ | |
694 | cur_cmd = linenum = 0; | |
695 | while (fgets(line, sizeof(line), f)) { | |
696 | linenum++; | |
697 | ||
698 | /* Skip leading whitespace, blank lines and comments */ | |
699 | cp = line + strspn(line, WHITESPACE); | |
700 | if ((*cp == 0) || (*cp == '#')) | |
701 | continue; /* done with this line */ | |
702 | ||
703 | /* | |
540d72c3 | 704 | * The first non-whitespace char should be a double quote |
d832c38e | 705 | * delimiting the commandline |
706 | */ | |
707 | if (*cp != '"') { | |
708 | error("bad entropy command, %.100s line %d", | |
709 | cmdfilename, linenum); | |
710 | continue; | |
711 | } | |
712 | ||
713 | /* | |
714 | * First token, command args (incl. argv[0]) in double | |
715 | * quotes | |
716 | */ | |
717 | cp = strtok(cp, "\""); | |
718 | if (cp == NULL) { | |
719 | error("missing or bad command string, %.100s " | |
720 | "line %d -- ignored", cmdfilename, linenum); | |
721 | continue; | |
722 | } | |
723 | strlcpy(cmd, cp, sizeof(cmd)); | |
724 | ||
725 | /* Second token, full command path */ | |
726 | if ((cp = strtok(NULL, WHITESPACE)) == NULL) { | |
727 | error("missing command path, %.100s " | |
728 | "line %d -- ignored", cmdfilename, linenum); | |
729 | continue; | |
730 | } | |
731 | ||
732 | /* Did configure mark this as dead? */ | |
733 | if (strncmp("undef", cp, 5) == 0) | |
734 | continue; | |
735 | ||
736 | strlcpy(path, cp, sizeof(path)); | |
737 | ||
738 | /* Third token, entropy rate estimate for this command */ | |
739 | if ((cp = strtok(NULL, WHITESPACE)) == NULL) { | |
740 | error("missing entropy estimate, %.100s " | |
741 | "line %d -- ignored", cmdfilename, linenum); | |
742 | continue; | |
743 | } | |
744 | est = strtod(cp, NULL); | |
745 | ||
746 | /* end of line */ | |
747 | if ((cp = strtok(NULL, WHITESPACE)) != NULL) { | |
748 | error("garbage at end of line %d in %.100s " | |
749 | "-- ignored", linenum, cmdfilename); | |
750 | continue; | |
751 | } | |
752 | ||
753 | /* save the command for debug messages */ | |
754 | entcmd[cur_cmd].cmdstring = xstrdup(cmd); | |
755 | ||
756 | /* split the command args */ | |
757 | cp = strtok(cmd, WHITESPACE); | |
758 | arg = 0; | |
759 | do { | |
760 | entcmd[cur_cmd].args[arg] = xstrdup(cp); | |
761 | arg++; | |
762 | } while(arg < NUM_ARGS && (cp = strtok(NULL, WHITESPACE))); | |
763 | ||
764 | if (strtok(NULL, WHITESPACE)) | |
765 | error("ignored extra commands (max %d), %.100s " | |
766 | "line %d", NUM_ARGS, cmdfilename, linenum); | |
767 | ||
768 | /* Copy the command path and rate estimate */ | |
769 | entcmd[cur_cmd].path = xstrdup(path); | |
770 | entcmd[cur_cmd].rate = est; | |
771 | ||
772 | /* Initialise other values */ | |
773 | entcmd[cur_cmd].sticky_badness = 1; | |
774 | ||
775 | cur_cmd++; | |
776 | ||
777 | /* | |
778 | * If we've filled the array, reallocate it twice the size | |
540d72c3 | 779 | * Do this now because even if this we're on the last |
d832c38e | 780 | * command we need another slot to mark the last entry |
781 | */ | |
782 | if (cur_cmd == num_cmds) { | |
783 | num_cmds *= 2; | |
30460aeb | 784 | entcmd = xrealloc(entcmd, num_cmds, |
d832c38e | 785 | sizeof(entropy_cmd_t)); |
786 | } | |
787 | } | |
788 | ||
789 | /* zero the last entry */ | |
790 | memset(&entcmd[cur_cmd], '\0', sizeof(entropy_cmd_t)); | |
791 | ||
792 | /* trim to size */ | |
30460aeb | 793 | entropy_cmds = xrealloc(entcmd, (cur_cmd + 1), |
d832c38e | 794 | sizeof(entropy_cmd_t)); |
795 | ||
796 | debug("Loaded %d entropy commands from %.100s", cur_cmd, | |
797 | cmdfilename); | |
798 | ||
30460aeb | 799 | fclose(f); |
d832c38e | 800 | return cur_cmd < MIN_ENTROPY_SOURCES ? -1 : 0; |
801 | } | |
802 | ||
350391c5 | 803 | void |
804 | usage(void) | |
805 | { | |
806 | fprintf(stderr, "Usage: %s [options]\n", __progname); | |
807 | fprintf(stderr, " -v Verbose; display verbose debugging messages.\n"); | |
808 | fprintf(stderr, " Multiple -v increases verbosity.\n"); | |
dfddba3d | 809 | fprintf(stderr, " -x Force output in hexadecimal (for debugging)\n"); |
350391c5 | 810 | fprintf(stderr, " -X Force output in binary\n"); |
811 | fprintf(stderr, " -b bytes Number of bytes to output (default %d)\n", | |
812 | OUTPUT_SEED_SIZE); | |
813 | } | |
814 | ||
540d72c3 | 815 | int |
d832c38e | 816 | main(int argc, char **argv) |
817 | { | |
350391c5 | 818 | unsigned char *buf; |
819 | int ret, ch, debug_level, output_hex, bytes; | |
820 | extern char *optarg; | |
821 | LogLevel ll; | |
d832c38e | 822 | |
7cac2b65 | 823 | __progname = ssh_get_progname(argv[0]); |
d832c38e | 824 | log_init(argv[0], SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_USER, 1); |
825 | ||
350391c5 | 826 | ll = SYSLOG_LEVEL_INFO; |
827 | debug_level = output_hex = 0; | |
828 | bytes = OUTPUT_SEED_SIZE; | |
829 | ||
830 | /* Don't write binary data to a tty, unless we are forced to */ | |
831 | if (isatty(STDOUT_FILENO)) | |
832 | output_hex = 1; | |
540d72c3 | 833 | |
350391c5 | 834 | while ((ch = getopt(argc, argv, "vxXhb:")) != -1) { |
835 | switch (ch) { | |
836 | case 'v': | |
837 | if (debug_level < 3) | |
838 | ll = SYSLOG_LEVEL_DEBUG1 + debug_level++; | |
839 | break; | |
840 | case 'x': | |
841 | output_hex = 1; | |
842 | break; | |
843 | case 'X': | |
844 | output_hex = 0; | |
845 | break; | |
846 | case 'b': | |
847 | if ((bytes = atoi(optarg)) <= 0) | |
848 | fatal("Invalid number of output bytes"); | |
849 | break; | |
850 | case 'h': | |
851 | usage(); | |
852 | exit(0); | |
853 | default: | |
854 | error("Invalid commandline option"); | |
855 | usage(); | |
856 | } | |
857 | } | |
858 | ||
859 | log_init(argv[0], ll, SYSLOG_FACILITY_USER, 1); | |
540d72c3 | 860 | |
d832c38e | 861 | #ifdef USE_SEED_FILES |
862 | prng_read_seedfile(); | |
863 | #endif | |
864 | ||
350391c5 | 865 | buf = xmalloc(bytes); |
866 | ||
d832c38e | 867 | /* |
868 | * Seed the RNG from wherever we can | |
869 | */ | |
540d72c3 | 870 | |
d832c38e | 871 | /* Take whatever is on the stack, but don't credit it */ |
350391c5 | 872 | RAND_add(buf, bytes, 0); |
d832c38e | 873 | |
540d72c3 | 874 | debug("Seeded RNG with %i bytes from system calls", |
d832c38e | 875 | (int)stir_from_system()); |
876 | ||
dfddba3d | 877 | /* try prngd, fall back to commands if prngd fails or not configured */ |
878 | if (seed_from_prngd(buf, bytes) == 0) { | |
879 | RAND_add(buf, bytes, bytes); | |
880 | } else { | |
881 | /* Read in collection commands */ | |
882 | if (prng_read_commands(SSH_PRNG_COMMAND_FILE) == -1) | |
883 | fatal("PRNG initialisation failed -- exiting."); | |
884 | debug("Seeded RNG with %i bytes from programs", | |
885 | (int)stir_from_programs()); | |
886 | } | |
d832c38e | 887 | |
888 | #ifdef USE_SEED_FILES | |
889 | prng_write_seedfile(); | |
890 | #endif | |
891 | ||
892 | /* | |
893 | * Write the seed to stdout | |
894 | */ | |
895 | ||
896 | if (!RAND_status()) | |
897 | fatal("Not enough entropy in RNG"); | |
898 | ||
bfe49944 | 899 | if (RAND_bytes(buf, bytes) <= 0) |
900 | fatal("Couldn't extract entropy from PRNG"); | |
d832c38e | 901 | |
350391c5 | 902 | if (output_hex) { |
903 | for(ret = 0; ret < bytes; ret++) | |
904 | printf("%02x", (unsigned char)(buf[ret])); | |
905 | printf("\n"); | |
906 | } else | |
7cac2b65 | 907 | ret = atomicio(vwrite, STDOUT_FILENO, buf, bytes); |
540d72c3 | 908 | |
350391c5 | 909 | memset(buf, '\0', bytes); |
910 | xfree(buf); | |
540d72c3 | 911 | |
350391c5 | 912 | return ret == bytes ? 0 : 1; |
d832c38e | 913 | } |
dfddba3d | 914 | |
915 | /* | |
916 | * We may attempt to re-seed during mkstemp if we are using the one in the | |
917 | * compat library (via mkstemp -> _gettemp -> arc4random -> seed_rng) so we | |
918 | * need our own seed_rng(). We must also check that we have enough entropy. | |
919 | */ | |
920 | void | |
921 | seed_rng(void) | |
922 | { | |
923 | if (!RAND_status()) | |
924 | fatal("Not enough entropy in RNG"); | |
925 | } |