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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 | ||
27 | #include <openssl/rand.h> | |
28 | #include <openssl/sha.h> | |
29 | #include <openssl/crypto.h> | |
30 | ||
31 | /* SunOS 4.4.4 needs this */ | |
32 | #ifdef HAVE_FLOATINGPOINT_H | |
33 | # include <floatingpoint.h> | |
34 | #endif /* HAVE_FLOATINGPOINT_H */ | |
35 | ||
36 | #include "misc.h" | |
37 | #include "xmalloc.h" | |
38 | #include "atomicio.h" | |
39 | #include "pathnames.h" | |
40 | #include "log.h" | |
41 | ||
42 | RCSID("$Id$"); | |
43 | ||
40f64e6f | 44 | /* Number of bytes we write out */ |
45 | #define OUTPUT_SEED_SIZE 48 | |
46 | ||
47 | /* Length of on-disk seedfiles */ | |
48 | #define SEED_FILE_SIZE 1024 | |
49 | ||
50 | /* Maximum number of command-line arguments to read from file */ | |
51 | #define NUM_ARGS 10 | |
52 | ||
53 | /* Minimum number of usable commands to be considered sufficient */ | |
54 | #define MIN_ENTROPY_SOURCES 16 | |
46058ce2 | 55 | |
40f64e6f | 56 | /* Path to on-disk seed file (relative to user's home directory */ |
46058ce2 | 57 | #ifndef SSH_PRNG_SEED_FILE |
58 | # define SSH_PRNG_SEED_FILE _PATH_SSH_USER_DIR"/prng_seed" | |
40f64e6f | 59 | #endif |
60 | ||
61 | /* Path to PRNG commands list */ | |
46058ce2 | 62 | #ifndef SSH_PRNG_COMMAND_FILE |
2a8a6488 | 63 | # define SSH_PRNG_COMMAND_FILE SSHDIR "/ssh_prng_cmds" |
40f64e6f | 64 | #endif |
46058ce2 | 65 | |
40f64e6f | 66 | extern char *__progname; |
40f64e6f | 67 | |
46058ce2 | 68 | #define WHITESPACE " \t\n" |
69 | ||
70 | #ifndef RUSAGE_SELF | |
71 | # define RUSAGE_SELF 0 | |
72 | #endif | |
73 | #ifndef RUSAGE_CHILDREN | |
74 | # define RUSAGE_CHILDREN 0 | |
75 | #endif | |
76 | ||
49d7ed32 | 77 | #if !defined(PRNGD_SOCKET) && !defined(PRNGD_PORT) |
40f64e6f | 78 | # define USE_SEED_FILES |
46058ce2 | 79 | #endif |
80 | ||
40f64e6f | 81 | typedef struct { |
82 | /* Proportion of data that is entropy */ | |
83 | double rate; | |
84 | /* Counter goes positive if this command times out */ | |
85 | unsigned int badness; | |
86 | /* Increases by factor of two each timeout */ | |
87 | unsigned int sticky_badness; | |
88 | /* Path to executable */ | |
89 | char *path; | |
90 | /* argv to pass to executable */ | |
91 | char *args[NUM_ARGS]; /* XXX: arbitrary limit */ | |
92 | /* full command string (debug) */ | |
93 | char *cmdstring; | |
94 | } entropy_cmd_t; | |
95 | ||
96 | /* slow command timeouts (all in milliseconds) */ | |
97 | /* static int entropy_timeout_default = ENTROPY_TIMEOUT_MSEC; */ | |
98 | static int entropy_timeout_current = ENTROPY_TIMEOUT_MSEC; | |
99 | ||
100 | /* this is initialised from a file, by prng_read_commands() */ | |
101 | static entropy_cmd_t *entropy_cmds = NULL; | |
102 | ||
103 | /* Prototypes */ | |
104 | double stir_from_system(void); | |
105 | double stir_from_programs(void); | |
106 | double stir_gettimeofday(double entropy_estimate); | |
107 | double stir_clock(double entropy_estimate); | |
108 | double stir_rusage(int who, double entropy_estimate); | |
75131bbd | 109 | double hash_command_output(entropy_cmd_t *src, unsigned char *hash); |
aff51935 | 110 | int get_random_bytes_prngd(unsigned char *buf, int len, |
40f64e6f | 111 | unsigned short tcp_port, char *socket_path); |
112 | ||
113 | /* | |
114 | * Collect 'len' bytes of entropy into 'buf' from PRNGD/EGD daemon | |
115 | * listening either on 'tcp_port', or via Unix domain socket at * | |
116 | * 'socket_path'. | |
aff51935 | 117 | * Either a non-zero tcp_port or a non-null socket_path must be |
40f64e6f | 118 | * supplied. |
119 | * Returns 0 on success, -1 on error | |
120 | */ | |
46058ce2 | 121 | int |
aff51935 | 122 | get_random_bytes_prngd(unsigned char *buf, int len, |
40f64e6f | 123 | unsigned short tcp_port, char *socket_path) |
46058ce2 | 124 | { |
40f64e6f | 125 | int fd, addr_len, rval, errors; |
46058ce2 | 126 | char msg[2]; |
40f64e6f | 127 | struct sockaddr_storage addr; |
128 | struct sockaddr_in *addr_in = (struct sockaddr_in *)&addr; | |
129 | struct sockaddr_un *addr_un = (struct sockaddr_un *)&addr; | |
46058ce2 | 130 | mysig_t old_sigpipe; |
131 | ||
40f64e6f | 132 | /* Sanity checks */ |
133 | if (socket_path == NULL && tcp_port == 0) | |
134 | fatal("You must specify a port or a socket"); | |
135 | if (socket_path != NULL && | |
136 | strlen(socket_path) >= sizeof(addr_un->sun_path)) | |
137 | fatal("Random pool path is too long"); | |
46058ce2 | 138 | if (len > 255) |
139 | fatal("Too many bytes to read from PRNGD"); | |
140 | ||
141 | memset(&addr, '\0', sizeof(addr)); | |
142 | ||
40f64e6f | 143 | if (tcp_port != 0) { |
144 | addr_in->sin_family = AF_INET; | |
145 | addr_in->sin_addr.s_addr = htonl(INADDR_LOOPBACK); | |
146 | addr_in->sin_port = htons(tcp_port); | |
147 | addr_len = sizeof(*addr_in); | |
148 | } else { | |
149 | addr_un->sun_family = AF_UNIX; | |
150 | strlcpy(addr_un->sun_path, socket_path, | |
151 | sizeof(addr_un->sun_path)); | |
152 | addr_len = offsetof(struct sockaddr_un, sun_path) + | |
153 | strlen(socket_path) + 1; | |
154 | } | |
46058ce2 | 155 | |
156 | old_sigpipe = mysignal(SIGPIPE, SIG_IGN); | |
157 | ||
40f64e6f | 158 | errors = 0; |
159 | rval = -1; | |
46058ce2 | 160 | reopen: |
40f64e6f | 161 | fd = socket(addr.ss_family, SOCK_STREAM, 0); |
46058ce2 | 162 | if (fd == -1) { |
40f64e6f | 163 | error("Couldn't create socket: %s", strerror(errno)); |
46058ce2 | 164 | goto done; |
165 | } | |
46058ce2 | 166 | |
167 | if (connect(fd, (struct sockaddr*)&addr, addr_len) == -1) { | |
40f64e6f | 168 | if (tcp_port != 0) { |
169 | error("Couldn't connect to PRNGD port %d: %s", | |
170 | tcp_port, strerror(errno)); | |
171 | } else { | |
172 | error("Couldn't connect to PRNGD socket \"%s\": %s", | |
173 | addr_un->sun_path, strerror(errno)); | |
174 | } | |
46058ce2 | 175 | goto done; |
176 | } | |
177 | ||
178 | /* Send blocking read request to PRNGD */ | |
179 | msg[0] = 0x02; | |
180 | msg[1] = len; | |
181 | ||
d72f7b79 | 182 | if (atomicio(vwrite, fd, msg, sizeof(msg)) != sizeof(msg)) { |
46058ce2 | 183 | if (errno == EPIPE && errors < 10) { |
184 | close(fd); | |
185 | errors++; | |
186 | goto reopen; | |
187 | } | |
188 | error("Couldn't write to PRNGD socket: %s", | |
189 | strerror(errno)); | |
190 | goto done; | |
191 | } | |
192 | ||
193 | if (atomicio(read, fd, buf, len) != len) { | |
194 | if (errno == EPIPE && errors < 10) { | |
195 | close(fd); | |
196 | errors++; | |
197 | goto reopen; | |
198 | } | |
199 | error("Couldn't read from PRNGD socket: %s", | |
200 | strerror(errno)); | |
201 | goto done; | |
202 | } | |
203 | ||
40f64e6f | 204 | rval = 0; |
46058ce2 | 205 | done: |
206 | mysignal(SIGPIPE, old_sigpipe); | |
207 | if (fd != -1) | |
208 | close(fd); | |
40f64e6f | 209 | return rval; |
46058ce2 | 210 | } |
211 | ||
212 | double | |
213 | stir_gettimeofday(double entropy_estimate) | |
214 | { | |
215 | struct timeval tv; | |
216 | ||
217 | if (gettimeofday(&tv, NULL) == -1) | |
218 | fatal("Couldn't gettimeofday: %s", strerror(errno)); | |
219 | ||
220 | RAND_add(&tv, sizeof(tv), entropy_estimate); | |
221 | ||
40f64e6f | 222 | return entropy_estimate; |
46058ce2 | 223 | } |
224 | ||
225 | double | |
226 | stir_clock(double entropy_estimate) | |
227 | { | |
228 | #ifdef HAVE_CLOCK | |
229 | clock_t c; | |
230 | ||
231 | c = clock(); | |
232 | RAND_add(&c, sizeof(c), entropy_estimate); | |
233 | ||
40f64e6f | 234 | return entropy_estimate; |
46058ce2 | 235 | #else /* _HAVE_CLOCK */ |
40f64e6f | 236 | return 0; |
46058ce2 | 237 | #endif /* _HAVE_CLOCK */ |
238 | } | |
239 | ||
240 | double | |
241 | stir_rusage(int who, double entropy_estimate) | |
242 | { | |
243 | #ifdef HAVE_GETRUSAGE | |
244 | struct rusage ru; | |
245 | ||
246 | if (getrusage(who, &ru) == -1) | |
40f64e6f | 247 | return 0; |
46058ce2 | 248 | |
249 | RAND_add(&ru, sizeof(ru), entropy_estimate); | |
250 | ||
40f64e6f | 251 | return entropy_estimate; |
46058ce2 | 252 | #else /* _HAVE_GETRUSAGE */ |
40f64e6f | 253 | return 0; |
46058ce2 | 254 | #endif /* _HAVE_GETRUSAGE */ |
255 | } | |
256 | ||
46058ce2 | 257 | static int |
40f64e6f | 258 | timeval_diff(struct timeval *t1, struct timeval *t2) |
259 | { | |
46058ce2 | 260 | int secdiff, usecdiff; |
261 | ||
262 | secdiff = t2->tv_sec - t1->tv_sec; | |
263 | usecdiff = (secdiff*1000000) + (t2->tv_usec - t1->tv_usec); | |
264 | return (int)(usecdiff / 1000); | |
265 | } | |
266 | ||
267 | double | |
75131bbd | 268 | hash_command_output(entropy_cmd_t *src, unsigned char *hash) |
46058ce2 | 269 | { |
40f64e6f | 270 | char buf[8192]; |
46058ce2 | 271 | fd_set rdset; |
40f64e6f | 272 | int bytes_read, cmd_eof, error_abort, msec_elapsed, p[2]; |
273 | int status, total_bytes_read; | |
274 | static int devnull = -1; | |
46058ce2 | 275 | pid_t pid; |
46058ce2 | 276 | SHA_CTX sha; |
40f64e6f | 277 | struct timeval tv_start, tv_current; |
46058ce2 | 278 | |
279 | debug3("Reading output from \'%s\'", src->cmdstring); | |
280 | ||
281 | if (devnull == -1) { | |
282 | devnull = open("/dev/null", O_RDWR); | |
283 | if (devnull == -1) | |
aff51935 | 284 | fatal("Couldn't open /dev/null: %s", |
40f64e6f | 285 | strerror(errno)); |
46058ce2 | 286 | } |
287 | ||
288 | if (pipe(p) == -1) | |
289 | fatal("Couldn't open pipe: %s", strerror(errno)); | |
290 | ||
291 | (void)gettimeofday(&tv_start, NULL); /* record start time */ | |
292 | ||
293 | switch (pid = fork()) { | |
294 | case -1: /* Error */ | |
295 | close(p[0]); | |
296 | close(p[1]); | |
297 | fatal("Couldn't fork: %s", strerror(errno)); | |
298 | /* NOTREACHED */ | |
299 | case 0: /* Child */ | |
300 | dup2(devnull, STDIN_FILENO); | |
301 | dup2(p[1], STDOUT_FILENO); | |
302 | dup2(p[1], STDERR_FILENO); | |
303 | close(p[0]); | |
304 | close(p[1]); | |
305 | close(devnull); | |
306 | ||
307 | execv(src->path, (char**)(src->args)); | |
40f64e6f | 308 | |
aff51935 | 309 | debug("(child) Couldn't exec '%s': %s", |
40f64e6f | 310 | src->cmdstring, strerror(errno)); |
46058ce2 | 311 | _exit(-1); |
312 | default: /* Parent */ | |
313 | break; | |
314 | } | |
315 | ||
316 | RAND_add(&pid, sizeof(&pid), 0.0); | |
317 | ||
318 | close(p[1]); | |
319 | ||
320 | /* Hash output from child */ | |
321 | SHA1_Init(&sha); | |
46058ce2 | 322 | |
40f64e6f | 323 | cmd_eof = error_abort = msec_elapsed = total_bytes_read = 0; |
46058ce2 | 324 | while (!error_abort && !cmd_eof) { |
325 | int ret; | |
326 | struct timeval tv; | |
327 | int msec_remaining; | |
328 | ||
329 | (void) gettimeofday(&tv_current, 0); | |
40f64e6f | 330 | msec_elapsed = timeval_diff(&tv_start, &tv_current); |
46058ce2 | 331 | if (msec_elapsed >= entropy_timeout_current) { |
332 | error_abort=1; | |
333 | continue; | |
334 | } | |
335 | msec_remaining = entropy_timeout_current - msec_elapsed; | |
336 | ||
337 | FD_ZERO(&rdset); | |
338 | FD_SET(p[0], &rdset); | |
40f64e6f | 339 | tv.tv_sec = msec_remaining / 1000; |
46058ce2 | 340 | tv.tv_usec = (msec_remaining % 1000) * 1000; |
341 | ||
40f64e6f | 342 | ret = select(p[0] + 1, &rdset, NULL, NULL, &tv); |
46058ce2 | 343 | |
344 | RAND_add(&tv, sizeof(tv), 0.0); | |
345 | ||
346 | switch (ret) { | |
347 | case 0: | |
348 | /* timer expired */ | |
349 | error_abort = 1; | |
4e6f1c4f | 350 | kill(pid, SIGINT); |
46058ce2 | 351 | break; |
352 | case 1: | |
353 | /* command input */ | |
354 | do { | |
355 | bytes_read = read(p[0], buf, sizeof(buf)); | |
356 | } while (bytes_read == -1 && errno == EINTR); | |
357 | RAND_add(&bytes_read, sizeof(&bytes_read), 0.0); | |
358 | if (bytes_read == -1) { | |
359 | error_abort = 1; | |
360 | break; | |
361 | } else if (bytes_read) { | |
362 | SHA1_Update(&sha, buf, bytes_read); | |
363 | total_bytes_read += bytes_read; | |
364 | } else { | |
365 | cmd_eof = 1; | |
366 | } | |
367 | break; | |
368 | case -1: | |
369 | default: | |
370 | /* error */ | |
aff51935 | 371 | debug("Command '%s': select() failed: %s", |
40f64e6f | 372 | src->cmdstring, strerror(errno)); |
46058ce2 | 373 | error_abort = 1; |
374 | break; | |
375 | } | |
376 | } | |
377 | ||
378 | SHA1_Final(hash, &sha); | |
379 | ||
380 | close(p[0]); | |
381 | ||
382 | debug3("Time elapsed: %d msec", msec_elapsed); | |
383 | ||
384 | if (waitpid(pid, &status, 0) == -1) { | |
40f64e6f | 385 | error("Couldn't wait for child '%s' completion: %s", |
875ec275 | 386 | src->cmdstring, strerror(errno)); |
40f64e6f | 387 | return 0.0; |
46058ce2 | 388 | } |
389 | ||
390 | RAND_add(&status, sizeof(&status), 0.0); | |
391 | ||
392 | if (error_abort) { | |
40f64e6f | 393 | /* |
394 | * Closing p[0] on timeout causes the entropy command to | |
aff51935 | 395 | * SIGPIPE. Take whatever output we got, and mark this |
396 | * command as slow | |
40f64e6f | 397 | */ |
46058ce2 | 398 | debug2("Command '%s' timed out", src->cmdstring); |
399 | src->sticky_badness *= 2; | |
400 | src->badness = src->sticky_badness; | |
40f64e6f | 401 | return total_bytes_read; |
46058ce2 | 402 | } |
403 | ||
404 | if (WIFEXITED(status)) { | |
40f64e6f | 405 | if (WEXITSTATUS(status) == 0) { |
406 | return total_bytes_read; | |
46058ce2 | 407 | } else { |
40f64e6f | 408 | debug2("Command '%s' exit status was %d", |
409 | src->cmdstring, WEXITSTATUS(status)); | |
46058ce2 | 410 | src->badness = src->sticky_badness = 128; |
40f64e6f | 411 | return 0.0; |
46058ce2 | 412 | } |
413 | } else if (WIFSIGNALED(status)) { | |
40f64e6f | 414 | debug2("Command '%s' returned on uncaught signal %d !", |
415 | src->cmdstring, status); | |
46058ce2 | 416 | src->badness = src->sticky_badness = 128; |
40f64e6f | 417 | return 0.0; |
46058ce2 | 418 | } else |
40f64e6f | 419 | return 0.0; |
420 | } | |
421 | ||
422 | double | |
423 | stir_from_system(void) | |
424 | { | |
425 | double total_entropy_estimate; | |
426 | long int i; | |
427 | ||
428 | total_entropy_estimate = 0; | |
429 | ||
430 | i = getpid(); | |
431 | RAND_add(&i, sizeof(i), 0.5); | |
432 | total_entropy_estimate += 0.1; | |
433 | ||
434 | i = getppid(); | |
435 | RAND_add(&i, sizeof(i), 0.5); | |
436 | total_entropy_estimate += 0.1; | |
437 | ||
438 | i = getuid(); | |
439 | RAND_add(&i, sizeof(i), 0.0); | |
440 | i = getgid(); | |
441 | RAND_add(&i, sizeof(i), 0.0); | |
442 | ||
443 | total_entropy_estimate += stir_gettimeofday(1.0); | |
444 | total_entropy_estimate += stir_clock(0.5); | |
445 | total_entropy_estimate += stir_rusage(RUSAGE_SELF, 2.0); | |
446 | ||
447 | return total_entropy_estimate; | |
448 | } | |
449 | ||
450 | double | |
451 | stir_from_programs(void) | |
452 | { | |
453 | int c; | |
454 | double entropy, total_entropy; | |
75131bbd | 455 | unsigned char hash[SHA_DIGEST_LENGTH]; |
40f64e6f | 456 | |
457 | total_entropy = 0; | |
458 | for(c = 0; entropy_cmds[c].path != NULL; c++) { | |
459 | if (!entropy_cmds[c].badness) { | |
460 | /* Hash output from command */ | |
461 | entropy = hash_command_output(&entropy_cmds[c], | |
462 | hash); | |
463 | ||
464 | /* Scale back estimate by command's rate */ | |
465 | entropy *= entropy_cmds[c].rate; | |
466 | ||
467 | /* Upper bound of entropy is SHA_DIGEST_LENGTH */ | |
468 | if (entropy > SHA_DIGEST_LENGTH) | |
469 | entropy = SHA_DIGEST_LENGTH; | |
470 | ||
471 | /* Stir it in */ | |
472 | RAND_add(hash, sizeof(hash), entropy); | |
473 | ||
aff51935 | 474 | debug3("Got %0.2f bytes of entropy from '%s'", |
40f64e6f | 475 | entropy, entropy_cmds[c].cmdstring); |
476 | ||
477 | total_entropy += entropy; | |
478 | ||
479 | /* Execution time should be a bit unpredictable */ | |
480 | total_entropy += stir_gettimeofday(0.05); | |
481 | total_entropy += stir_clock(0.05); | |
482 | total_entropy += stir_rusage(RUSAGE_SELF, 0.1); | |
483 | total_entropy += stir_rusage(RUSAGE_CHILDREN, 0.1); | |
484 | } else { | |
485 | debug2("Command '%s' disabled (badness %d)", | |
aff51935 | 486 | entropy_cmds[c].cmdstring, |
40f64e6f | 487 | entropy_cmds[c].badness); |
488 | ||
489 | if (entropy_cmds[c].badness > 0) | |
490 | entropy_cmds[c].badness--; | |
491 | } | |
492 | } | |
493 | ||
494 | return total_entropy; | |
46058ce2 | 495 | } |
496 | ||
497 | /* | |
498 | * prng seedfile functions | |
499 | */ | |
500 | int | |
40f64e6f | 501 | prng_check_seedfile(char *filename) |
502 | { | |
46058ce2 | 503 | struct stat st; |
504 | ||
40f64e6f | 505 | /* |
aff51935 | 506 | * XXX raceable: eg replace seed between this stat and subsequent |
507 | * open. Not such a problem because we don't really trust the | |
40f64e6f | 508 | * seed file anyway. |
509 | * XXX: use secure path checking as elsewhere in OpenSSH | |
510 | */ | |
46058ce2 | 511 | if (lstat(filename, &st) == -1) { |
512 | /* Give up on hard errors */ | |
513 | if (errno != ENOENT) | |
40f64e6f | 514 | debug("WARNING: Couldn't stat random seed file " |
515 | "\"%.100s\": %s", filename, strerror(errno)); | |
516 | return 0; | |
46058ce2 | 517 | } |
518 | ||
519 | /* regular file? */ | |
520 | if (!S_ISREG(st.st_mode)) | |
40f64e6f | 521 | fatal("PRNG seedfile %.100s is not a regular file", |
522 | filename); | |
46058ce2 | 523 | |
524 | /* mode 0600, owned by root or the current user? */ | |
525 | if (((st.st_mode & 0177) != 0) || !(st.st_uid == getuid())) { | |
40f64e6f | 526 | debug("WARNING: PRNG seedfile %.100s must be mode 0600, " |
7be625e1 | 527 | "owned by uid %li", filename, (long int)getuid()); |
40f64e6f | 528 | return 0; |
46058ce2 | 529 | } |
530 | ||
40f64e6f | 531 | return 1; |
46058ce2 | 532 | } |
533 | ||
534 | void | |
40f64e6f | 535 | prng_write_seedfile(void) |
536 | { | |
46058ce2 | 537 | int fd; |
75131bbd | 538 | unsigned char seed[SEED_FILE_SIZE]; |
539 | char filename[MAXPATHLEN]; | |
46058ce2 | 540 | struct passwd *pw; |
541 | ||
542 | pw = getpwuid(getuid()); | |
543 | if (pw == NULL) | |
40f64e6f | 544 | fatal("Couldn't get password entry for current user " |
7be625e1 | 545 | "(%li): %s", (long int)getuid(), strerror(errno)); |
46058ce2 | 546 | |
547 | /* Try to ensure that the parent directory is there */ | |
548 | snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir, | |
40f64e6f | 549 | _PATH_SSH_USER_DIR); |
46058ce2 | 550 | mkdir(filename, 0700); |
551 | ||
552 | snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir, | |
40f64e6f | 553 | SSH_PRNG_SEED_FILE); |
46058ce2 | 554 | |
555 | debug("writing PRNG seed to file %.100s", filename); | |
556 | ||
d8eb5247 | 557 | if (RAND_bytes(seed, sizeof(seed)) <= 0) |
9e3191db | 558 | fatal("PRNG seed extraction failed"); |
46058ce2 | 559 | |
560 | /* Don't care if the seed doesn't exist */ | |
561 | prng_check_seedfile(filename); | |
562 | ||
563 | if ((fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0600)) == -1) { | |
40f64e6f | 564 | debug("WARNING: couldn't access PRNG seedfile %.100s " |
565 | "(%.100s)", filename, strerror(errno)); | |
46058ce2 | 566 | } else { |
d72f7b79 | 567 | if (atomicio(vwrite, fd, &seed, sizeof(seed)) < sizeof(seed)) |
40f64e6f | 568 | fatal("problem writing PRNG seedfile %.100s " |
569 | "(%.100s)", filename, strerror(errno)); | |
46058ce2 | 570 | close(fd); |
571 | } | |
572 | } | |
573 | ||
574 | void | |
40f64e6f | 575 | prng_read_seedfile(void) |
576 | { | |
46058ce2 | 577 | int fd; |
40f64e6f | 578 | char seed[SEED_FILE_SIZE], filename[MAXPATHLEN]; |
46058ce2 | 579 | struct passwd *pw; |
580 | ||
581 | pw = getpwuid(getuid()); | |
582 | if (pw == NULL) | |
40f64e6f | 583 | fatal("Couldn't get password entry for current user " |
7be625e1 | 584 | "(%li): %s", (long int)getuid(), strerror(errno)); |
46058ce2 | 585 | |
586 | snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir, | |
587 | SSH_PRNG_SEED_FILE); | |
588 | ||
589 | debug("loading PRNG seed from file %.100s", filename); | |
590 | ||
591 | if (!prng_check_seedfile(filename)) { | |
40f64e6f | 592 | verbose("Random seed file not found or invalid, ignoring."); |
46058ce2 | 593 | return; |
594 | } | |
595 | ||
596 | /* open the file and read in the seed */ | |
597 | fd = open(filename, O_RDONLY); | |
598 | if (fd == -1) | |
40f64e6f | 599 | fatal("could not open PRNG seedfile %.100s (%.100s)", |
600 | filename, strerror(errno)); | |
46058ce2 | 601 | |
40f64e6f | 602 | if (atomicio(read, fd, &seed, sizeof(seed)) < sizeof(seed)) { |
603 | verbose("invalid or short read from PRNG seedfile " | |
604 | "%.100s - ignoring", filename); | |
46058ce2 | 605 | memset(seed, '\0', sizeof(seed)); |
606 | } | |
607 | close(fd); | |
608 | ||
609 | /* stir in the seed, with estimated entropy zero */ | |
610 | RAND_add(&seed, sizeof(seed), 0.0); | |
611 | } | |
612 | ||
613 | ||
614 | /* | |
615 | * entropy command initialisation functions | |
616 | */ | |
617 | int | |
618 | prng_read_commands(char *cmdfilename) | |
619 | { | |
40f64e6f | 620 | char cmd[SEED_FILE_SIZE], *cp, line[1024], path[SEED_FILE_SIZE]; |
46058ce2 | 621 | double est; |
40f64e6f | 622 | entropy_cmd_t *entcmd; |
623 | FILE *f; | |
624 | int cur_cmd, linenum, num_cmds, arg; | |
46058ce2 | 625 | |
40f64e6f | 626 | if ((f = fopen(cmdfilename, "r")) == NULL) { |
46058ce2 | 627 | fatal("couldn't read entropy commands file %.100s: %.100s", |
628 | cmdfilename, strerror(errno)); | |
629 | } | |
630 | ||
40f64e6f | 631 | num_cmds = 64; |
632 | entcmd = xmalloc(num_cmds * sizeof(entropy_cmd_t)); | |
633 | memset(entcmd, '\0', num_cmds * sizeof(entropy_cmd_t)); | |
46058ce2 | 634 | |
635 | /* Read in file */ | |
40f64e6f | 636 | cur_cmd = linenum = 0; |
46058ce2 | 637 | while (fgets(line, sizeof(line), f)) { |
46058ce2 | 638 | linenum++; |
639 | ||
40f64e6f | 640 | /* Skip leading whitespace, blank lines and comments */ |
46058ce2 | 641 | cp = line + strspn(line, WHITESPACE); |
642 | if ((*cp == 0) || (*cp == '#')) | |
643 | continue; /* done with this line */ | |
644 | ||
40f64e6f | 645 | /* |
aff51935 | 646 | * The first non-whitespace char should be a double quote |
40f64e6f | 647 | * delimiting the commandline |
648 | */ | |
46058ce2 | 649 | if (*cp != '"') { |
40f64e6f | 650 | error("bad entropy command, %.100s line %d", |
651 | cmdfilename, linenum); | |
46058ce2 | 652 | continue; |
653 | } | |
654 | ||
40f64e6f | 655 | /* |
656 | * First token, command args (incl. argv[0]) in double | |
657 | * quotes | |
658 | */ | |
46058ce2 | 659 | cp = strtok(cp, "\""); |
660 | if (cp == NULL) { | |
40f64e6f | 661 | error("missing or bad command string, %.100s " |
662 | "line %d -- ignored", cmdfilename, linenum); | |
46058ce2 | 663 | continue; |
664 | } | |
665 | strlcpy(cmd, cp, sizeof(cmd)); | |
666 | ||
40f64e6f | 667 | /* Second token, full command path */ |
46058ce2 | 668 | if ((cp = strtok(NULL, WHITESPACE)) == NULL) { |
40f64e6f | 669 | error("missing command path, %.100s " |
670 | "line %d -- ignored", cmdfilename, linenum); | |
46058ce2 | 671 | continue; |
672 | } | |
673 | ||
40f64e6f | 674 | /* Did configure mark this as dead? */ |
46058ce2 | 675 | if (strncmp("undef", cp, 5) == 0) |
676 | continue; | |
677 | ||
678 | strlcpy(path, cp, sizeof(path)); | |
679 | ||
40f64e6f | 680 | /* Third token, entropy rate estimate for this command */ |
46058ce2 | 681 | if ((cp = strtok(NULL, WHITESPACE)) == NULL) { |
40f64e6f | 682 | error("missing entropy estimate, %.100s " |
683 | "line %d -- ignored", cmdfilename, linenum); | |
46058ce2 | 684 | continue; |
685 | } | |
40f64e6f | 686 | est = strtod(cp, NULL); |
46058ce2 | 687 | |
688 | /* end of line */ | |
689 | if ((cp = strtok(NULL, WHITESPACE)) != NULL) { | |
40f64e6f | 690 | error("garbage at end of line %d in %.100s " |
691 | "-- ignored", linenum, cmdfilename); | |
46058ce2 | 692 | continue; |
693 | } | |
694 | ||
695 | /* save the command for debug messages */ | |
696 | entcmd[cur_cmd].cmdstring = xstrdup(cmd); | |
697 | ||
698 | /* split the command args */ | |
699 | cp = strtok(cmd, WHITESPACE); | |
700 | arg = 0; | |
46058ce2 | 701 | do { |
40f64e6f | 702 | entcmd[cur_cmd].args[arg] = xstrdup(cp); |
46058ce2 | 703 | arg++; |
40f64e6f | 704 | } while(arg < NUM_ARGS && (cp = strtok(NULL, WHITESPACE))); |
46058ce2 | 705 | |
706 | if (strtok(NULL, WHITESPACE)) | |
40f64e6f | 707 | error("ignored extra commands (max %d), %.100s " |
708 | "line %d", NUM_ARGS, cmdfilename, linenum); | |
46058ce2 | 709 | |
710 | /* Copy the command path and rate estimate */ | |
711 | entcmd[cur_cmd].path = xstrdup(path); | |
712 | entcmd[cur_cmd].rate = est; | |
713 | ||
714 | /* Initialise other values */ | |
715 | entcmd[cur_cmd].sticky_badness = 1; | |
716 | ||
717 | cur_cmd++; | |
718 | ||
40f64e6f | 719 | /* |
720 | * If we've filled the array, reallocate it twice the size | |
aff51935 | 721 | * Do this now because even if this we're on the last |
40f64e6f | 722 | * command we need another slot to mark the last entry |
723 | */ | |
46058ce2 | 724 | if (cur_cmd == num_cmds) { |
725 | num_cmds *= 2; | |
40f64e6f | 726 | entcmd = xrealloc(entcmd, num_cmds * |
727 | sizeof(entropy_cmd_t)); | |
46058ce2 | 728 | } |
729 | } | |
730 | ||
731 | /* zero the last entry */ | |
40f64e6f | 732 | memset(&entcmd[cur_cmd], '\0', sizeof(entropy_cmd_t)); |
46058ce2 | 733 | |
734 | /* trim to size */ | |
40f64e6f | 735 | entropy_cmds = xrealloc(entcmd, (cur_cmd + 1) * |
736 | sizeof(entropy_cmd_t)); | |
46058ce2 | 737 | |
40f64e6f | 738 | debug("Loaded %d entropy commands from %.100s", cur_cmd, |
739 | cmdfilename); | |
46058ce2 | 740 | |
40f64e6f | 741 | return cur_cmd < MIN_ENTROPY_SOURCES ? -1 : 0; |
46058ce2 | 742 | } |
743 | ||
f6e6303d | 744 | void |
745 | usage(void) | |
746 | { | |
747 | fprintf(stderr, "Usage: %s [options]\n", __progname); | |
748 | fprintf(stderr, " -v Verbose; display verbose debugging messages.\n"); | |
749 | fprintf(stderr, " Multiple -v increases verbosity.\n"); | |
750 | fprintf(stderr, " -x Force output in hexidecimal (for debugging)\n"); | |
751 | fprintf(stderr, " -X Force output in binary\n"); | |
752 | fprintf(stderr, " -b bytes Number of bytes to output (default %d)\n", | |
753 | OUTPUT_SEED_SIZE); | |
754 | } | |
755 | ||
aff51935 | 756 | int |
46058ce2 | 757 | main(int argc, char **argv) |
758 | { | |
f6e6303d | 759 | unsigned char *buf; |
760 | int ret, ch, debug_level, output_hex, bytes; | |
761 | extern char *optarg; | |
762 | LogLevel ll; | |
46058ce2 | 763 | |
fda04d7d | 764 | __progname = ssh_get_progname(argv[0]); |
46058ce2 | 765 | log_init(argv[0], SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_USER, 1); |
766 | ||
f6e6303d | 767 | ll = SYSLOG_LEVEL_INFO; |
768 | debug_level = output_hex = 0; | |
769 | bytes = OUTPUT_SEED_SIZE; | |
770 | ||
771 | /* Don't write binary data to a tty, unless we are forced to */ | |
772 | if (isatty(STDOUT_FILENO)) | |
773 | output_hex = 1; | |
b6453d99 | 774 | |
f6e6303d | 775 | while ((ch = getopt(argc, argv, "vxXhb:")) != -1) { |
776 | switch (ch) { | |
777 | case 'v': | |
778 | if (debug_level < 3) | |
779 | ll = SYSLOG_LEVEL_DEBUG1 + debug_level++; | |
780 | break; | |
781 | case 'x': | |
782 | output_hex = 1; | |
783 | break; | |
784 | case 'X': | |
785 | output_hex = 0; | |
786 | break; | |
787 | case 'b': | |
788 | if ((bytes = atoi(optarg)) <= 0) | |
789 | fatal("Invalid number of output bytes"); | |
790 | break; | |
791 | case 'h': | |
792 | usage(); | |
793 | exit(0); | |
794 | default: | |
795 | error("Invalid commandline option"); | |
796 | usage(); | |
797 | } | |
798 | } | |
799 | ||
800 | log_init(argv[0], ll, SYSLOG_FACILITY_USER, 1); | |
b6453d99 | 801 | |
40f64e6f | 802 | #ifdef USE_SEED_FILES |
803 | prng_read_seedfile(); | |
804 | #endif | |
805 | ||
f6e6303d | 806 | buf = xmalloc(bytes); |
807 | ||
40f64e6f | 808 | /* |
809 | * Seed the RNG from wherever we can | |
810 | */ | |
b6453d99 | 811 | |
40f64e6f | 812 | /* Take whatever is on the stack, but don't credit it */ |
f6e6303d | 813 | RAND_add(buf, bytes, 0); |
40f64e6f | 814 | |
aff51935 | 815 | debug("Seeded RNG with %i bytes from system calls", |
40f64e6f | 816 | (int)stir_from_system()); |
817 | ||
818 | #ifdef PRNGD_PORT | |
f6e6303d | 819 | if (get_random_bytes_prngd(buf, bytes, PRNGD_PORT, NULL) == -1) |
40f64e6f | 820 | fatal("Entropy collection failed"); |
f6e6303d | 821 | RAND_add(buf, bytes, bytes); |
49d7ed32 | 822 | #elif defined(PRNGD_SOCKET) |
f6e6303d | 823 | if (get_random_bytes_prngd(buf, bytes, 0, PRNGD_SOCKET) == -1) |
40f64e6f | 824 | fatal("Entropy collection failed"); |
f6e6303d | 825 | RAND_add(buf, bytes, bytes); |
40f64e6f | 826 | #else |
827 | /* Read in collection commands */ | |
828 | if (prng_read_commands(SSH_PRNG_COMMAND_FILE) == -1) | |
829 | fatal("PRNG initialisation failed -- exiting."); | |
aff51935 | 830 | debug("Seeded RNG with %i bytes from programs", |
40f64e6f | 831 | (int)stir_from_programs()); |
832 | #endif | |
833 | ||
834 | #ifdef USE_SEED_FILES | |
835 | prng_write_seedfile(); | |
836 | #endif | |
837 | ||
838 | /* | |
839 | * Write the seed to stdout | |
840 | */ | |
46058ce2 | 841 | |
842 | if (!RAND_status()) | |
843 | fatal("Not enough entropy in RNG"); | |
844 | ||
d8eb5247 | 845 | if (RAND_bytes(buf, bytes) <= 0) |
846 | fatal("Couldn't extract entropy from PRNG"); | |
46058ce2 | 847 | |
f6e6303d | 848 | if (output_hex) { |
849 | for(ret = 0; ret < bytes; ret++) | |
850 | printf("%02x", (unsigned char)(buf[ret])); | |
851 | printf("\n"); | |
852 | } else | |
d72f7b79 | 853 | ret = atomicio(vwrite, STDOUT_FILENO, buf, bytes); |
b6453d99 | 854 | |
f6e6303d | 855 | memset(buf, '\0', bytes); |
856 | xfree(buf); | |
b6453d99 | 857 | |
f6e6303d | 858 | return ret == bytes ? 0 : 1; |
46058ce2 | 859 | } |