]>
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> | |
9794d008 | 31 | #include <sys/socket.h> |
35d1c2de | 32 | |
33 | #include <stdarg.h> | |
bcaab305 | 34 | #include <stddef.h> |
9794d008 | 35 | |
36 | #include <netinet/in.h> | |
cb2c6179 | 37 | |
38 | #ifdef HAVE_SYS_UN_H | |
39 | # include <sys/un.h> | |
40 | #endif | |
41 | ||
403a29ac | 42 | #include <errno.h> |
22bbb3e6 | 43 | #include <fcntl.h> |
b1842393 | 44 | #include <pwd.h> |
cb2c6179 | 45 | #include <signal.h> |
28cb0a43 | 46 | #include <time.h> |
47 | #include <unistd.h> | |
cb2c6179 | 48 | |
46058ce2 | 49 | #include <openssl/rand.h> |
50 | #include <openssl/sha.h> | |
51 | #include <openssl/crypto.h> | |
52 | ||
53 | /* SunOS 4.4.4 needs this */ | |
54 | #ifdef HAVE_FLOATINGPOINT_H | |
55 | # include <floatingpoint.h> | |
56 | #endif /* HAVE_FLOATINGPOINT_H */ | |
57 | ||
58 | #include "misc.h" | |
59 | #include "xmalloc.h" | |
60 | #include "atomicio.h" | |
61 | #include "pathnames.h" | |
62 | #include "log.h" | |
63 | ||
40f64e6f | 64 | /* Number of bytes we write out */ |
65 | #define OUTPUT_SEED_SIZE 48 | |
66 | ||
67 | /* Length of on-disk seedfiles */ | |
68 | #define SEED_FILE_SIZE 1024 | |
69 | ||
70 | /* Maximum number of command-line arguments to read from file */ | |
71 | #define NUM_ARGS 10 | |
72 | ||
73 | /* Minimum number of usable commands to be considered sufficient */ | |
74 | #define MIN_ENTROPY_SOURCES 16 | |
46058ce2 | 75 | |
40f64e6f | 76 | /* Path to on-disk seed file (relative to user's home directory */ |
46058ce2 | 77 | #ifndef SSH_PRNG_SEED_FILE |
78 | # define SSH_PRNG_SEED_FILE _PATH_SSH_USER_DIR"/prng_seed" | |
40f64e6f | 79 | #endif |
80 | ||
81 | /* Path to PRNG commands list */ | |
46058ce2 | 82 | #ifndef SSH_PRNG_COMMAND_FILE |
2a8a6488 | 83 | # define SSH_PRNG_COMMAND_FILE SSHDIR "/ssh_prng_cmds" |
40f64e6f | 84 | #endif |
46058ce2 | 85 | |
40f64e6f | 86 | extern char *__progname; |
40f64e6f | 87 | |
46058ce2 | 88 | #define WHITESPACE " \t\n" |
89 | ||
90 | #ifndef RUSAGE_SELF | |
91 | # define RUSAGE_SELF 0 | |
92 | #endif | |
93 | #ifndef RUSAGE_CHILDREN | |
94 | # define RUSAGE_CHILDREN 0 | |
95 | #endif | |
96 | ||
49d7ed32 | 97 | #if !defined(PRNGD_SOCKET) && !defined(PRNGD_PORT) |
40f64e6f | 98 | # define USE_SEED_FILES |
46058ce2 | 99 | #endif |
100 | ||
40f64e6f | 101 | typedef struct { |
102 | /* Proportion of data that is entropy */ | |
103 | double rate; | |
104 | /* Counter goes positive if this command times out */ | |
105 | unsigned int badness; | |
106 | /* Increases by factor of two each timeout */ | |
107 | unsigned int sticky_badness; | |
108 | /* Path to executable */ | |
109 | char *path; | |
110 | /* argv to pass to executable */ | |
111 | char *args[NUM_ARGS]; /* XXX: arbitrary limit */ | |
112 | /* full command string (debug) */ | |
113 | char *cmdstring; | |
114 | } entropy_cmd_t; | |
115 | ||
116 | /* slow command timeouts (all in milliseconds) */ | |
117 | /* static int entropy_timeout_default = ENTROPY_TIMEOUT_MSEC; */ | |
118 | static int entropy_timeout_current = ENTROPY_TIMEOUT_MSEC; | |
119 | ||
120 | /* this is initialised from a file, by prng_read_commands() */ | |
121 | static entropy_cmd_t *entropy_cmds = NULL; | |
122 | ||
123 | /* Prototypes */ | |
124 | double stir_from_system(void); | |
125 | double stir_from_programs(void); | |
126 | double stir_gettimeofday(double entropy_estimate); | |
127 | double stir_clock(double entropy_estimate); | |
128 | double stir_rusage(int who, double entropy_estimate); | |
75131bbd | 129 | double hash_command_output(entropy_cmd_t *src, unsigned char *hash); |
aff51935 | 130 | int get_random_bytes_prngd(unsigned char *buf, int len, |
40f64e6f | 131 | unsigned short tcp_port, char *socket_path); |
132 | ||
133 | /* | |
134 | * Collect 'len' bytes of entropy into 'buf' from PRNGD/EGD daemon | |
135 | * listening either on 'tcp_port', or via Unix domain socket at * | |
136 | * 'socket_path'. | |
aff51935 | 137 | * Either a non-zero tcp_port or a non-null socket_path must be |
40f64e6f | 138 | * supplied. |
139 | * Returns 0 on success, -1 on error | |
140 | */ | |
46058ce2 | 141 | int |
aff51935 | 142 | get_random_bytes_prngd(unsigned char *buf, int len, |
40f64e6f | 143 | unsigned short tcp_port, char *socket_path) |
46058ce2 | 144 | { |
40f64e6f | 145 | int fd, addr_len, rval, errors; |
44d71ad5 | 146 | u_char msg[2]; |
40f64e6f | 147 | struct sockaddr_storage addr; |
148 | struct sockaddr_in *addr_in = (struct sockaddr_in *)&addr; | |
149 | struct sockaddr_un *addr_un = (struct sockaddr_un *)&addr; | |
46058ce2 | 150 | mysig_t old_sigpipe; |
151 | ||
40f64e6f | 152 | /* Sanity checks */ |
153 | if (socket_path == NULL && tcp_port == 0) | |
154 | fatal("You must specify a port or a socket"); | |
155 | if (socket_path != NULL && | |
156 | strlen(socket_path) >= sizeof(addr_un->sun_path)) | |
157 | fatal("Random pool path is too long"); | |
44d71ad5 | 158 | if (len <= 0 || len > 255) |
159 | fatal("Too many bytes (%d) to read from PRNGD", len); | |
46058ce2 | 160 | |
161 | memset(&addr, '\0', sizeof(addr)); | |
162 | ||
40f64e6f | 163 | if (tcp_port != 0) { |
164 | addr_in->sin_family = AF_INET; | |
165 | addr_in->sin_addr.s_addr = htonl(INADDR_LOOPBACK); | |
166 | addr_in->sin_port = htons(tcp_port); | |
167 | addr_len = sizeof(*addr_in); | |
168 | } else { | |
169 | addr_un->sun_family = AF_UNIX; | |
170 | strlcpy(addr_un->sun_path, socket_path, | |
171 | sizeof(addr_un->sun_path)); | |
172 | addr_len = offsetof(struct sockaddr_un, sun_path) + | |
173 | strlen(socket_path) + 1; | |
174 | } | |
46058ce2 | 175 | |
176 | old_sigpipe = mysignal(SIGPIPE, SIG_IGN); | |
177 | ||
40f64e6f | 178 | errors = 0; |
179 | rval = -1; | |
46058ce2 | 180 | reopen: |
40f64e6f | 181 | fd = socket(addr.ss_family, SOCK_STREAM, 0); |
46058ce2 | 182 | if (fd == -1) { |
40f64e6f | 183 | error("Couldn't create socket: %s", strerror(errno)); |
46058ce2 | 184 | goto done; |
185 | } | |
46058ce2 | 186 | |
187 | if (connect(fd, (struct sockaddr*)&addr, addr_len) == -1) { | |
40f64e6f | 188 | if (tcp_port != 0) { |
189 | error("Couldn't connect to PRNGD port %d: %s", | |
190 | tcp_port, strerror(errno)); | |
191 | } else { | |
192 | error("Couldn't connect to PRNGD socket \"%s\": %s", | |
193 | addr_un->sun_path, strerror(errno)); | |
194 | } | |
46058ce2 | 195 | goto done; |
196 | } | |
197 | ||
198 | /* Send blocking read request to PRNGD */ | |
199 | msg[0] = 0x02; | |
200 | msg[1] = len; | |
201 | ||
d72f7b79 | 202 | if (atomicio(vwrite, fd, msg, sizeof(msg)) != sizeof(msg)) { |
46058ce2 | 203 | if (errno == EPIPE && errors < 10) { |
204 | close(fd); | |
205 | errors++; | |
206 | goto reopen; | |
207 | } | |
208 | error("Couldn't write to PRNGD socket: %s", | |
209 | strerror(errno)); | |
210 | goto done; | |
211 | } | |
212 | ||
44d71ad5 | 213 | if (atomicio(read, fd, buf, len) != (size_t)len) { |
46058ce2 | 214 | if (errno == EPIPE && errors < 10) { |
215 | close(fd); | |
216 | errors++; | |
217 | goto reopen; | |
218 | } | |
219 | error("Couldn't read from PRNGD socket: %s", | |
220 | strerror(errno)); | |
221 | goto done; | |
222 | } | |
223 | ||
40f64e6f | 224 | rval = 0; |
46058ce2 | 225 | done: |
226 | mysignal(SIGPIPE, old_sigpipe); | |
227 | if (fd != -1) | |
228 | close(fd); | |
40f64e6f | 229 | return rval; |
46058ce2 | 230 | } |
231 | ||
1e111f05 | 232 | static int |
233 | seed_from_prngd(unsigned char *buf, size_t bytes) | |
234 | { | |
235 | #ifdef PRNGD_PORT | |
236 | debug("trying egd/prngd port %d", PRNGD_PORT); | |
237 | if (get_random_bytes_prngd(buf, bytes, PRNGD_PORT, NULL) == 0) | |
238 | return 0; | |
239 | #endif | |
240 | #ifdef PRNGD_SOCKET | |
241 | debug("trying egd/prngd socket %s", PRNGD_SOCKET); | |
242 | if (get_random_bytes_prngd(buf, bytes, 0, PRNGD_SOCKET) == 0) | |
243 | return 0; | |
244 | #endif | |
245 | return -1; | |
246 | } | |
247 | ||
46058ce2 | 248 | double |
249 | stir_gettimeofday(double entropy_estimate) | |
250 | { | |
251 | struct timeval tv; | |
252 | ||
253 | if (gettimeofday(&tv, NULL) == -1) | |
254 | fatal("Couldn't gettimeofday: %s", strerror(errno)); | |
255 | ||
256 | RAND_add(&tv, sizeof(tv), entropy_estimate); | |
257 | ||
40f64e6f | 258 | return entropy_estimate; |
46058ce2 | 259 | } |
260 | ||
261 | double | |
262 | stir_clock(double entropy_estimate) | |
263 | { | |
264 | #ifdef HAVE_CLOCK | |
265 | clock_t c; | |
266 | ||
267 | c = clock(); | |
268 | RAND_add(&c, sizeof(c), entropy_estimate); | |
269 | ||
40f64e6f | 270 | return entropy_estimate; |
46058ce2 | 271 | #else /* _HAVE_CLOCK */ |
40f64e6f | 272 | return 0; |
46058ce2 | 273 | #endif /* _HAVE_CLOCK */ |
274 | } | |
275 | ||
276 | double | |
277 | stir_rusage(int who, double entropy_estimate) | |
278 | { | |
279 | #ifdef HAVE_GETRUSAGE | |
280 | struct rusage ru; | |
281 | ||
282 | if (getrusage(who, &ru) == -1) | |
40f64e6f | 283 | return 0; |
46058ce2 | 284 | |
285 | RAND_add(&ru, sizeof(ru), entropy_estimate); | |
286 | ||
40f64e6f | 287 | return entropy_estimate; |
46058ce2 | 288 | #else /* _HAVE_GETRUSAGE */ |
40f64e6f | 289 | return 0; |
46058ce2 | 290 | #endif /* _HAVE_GETRUSAGE */ |
291 | } | |
292 | ||
46058ce2 | 293 | static int |
40f64e6f | 294 | timeval_diff(struct timeval *t1, struct timeval *t2) |
295 | { | |
46058ce2 | 296 | int secdiff, usecdiff; |
297 | ||
298 | secdiff = t2->tv_sec - t1->tv_sec; | |
299 | usecdiff = (secdiff*1000000) + (t2->tv_usec - t1->tv_usec); | |
300 | return (int)(usecdiff / 1000); | |
301 | } | |
302 | ||
303 | double | |
75131bbd | 304 | hash_command_output(entropy_cmd_t *src, unsigned char *hash) |
46058ce2 | 305 | { |
40f64e6f | 306 | char buf[8192]; |
46058ce2 | 307 | fd_set rdset; |
40f64e6f | 308 | int bytes_read, cmd_eof, error_abort, msec_elapsed, p[2]; |
309 | int status, total_bytes_read; | |
310 | static int devnull = -1; | |
46058ce2 | 311 | pid_t pid; |
46058ce2 | 312 | SHA_CTX sha; |
40f64e6f | 313 | struct timeval tv_start, tv_current; |
46058ce2 | 314 | |
315 | debug3("Reading output from \'%s\'", src->cmdstring); | |
316 | ||
317 | if (devnull == -1) { | |
318 | devnull = open("/dev/null", O_RDWR); | |
319 | if (devnull == -1) | |
aff51935 | 320 | fatal("Couldn't open /dev/null: %s", |
40f64e6f | 321 | strerror(errno)); |
46058ce2 | 322 | } |
323 | ||
324 | if (pipe(p) == -1) | |
325 | fatal("Couldn't open pipe: %s", strerror(errno)); | |
326 | ||
327 | (void)gettimeofday(&tv_start, NULL); /* record start time */ | |
328 | ||
329 | switch (pid = fork()) { | |
330 | case -1: /* Error */ | |
331 | close(p[0]); | |
332 | close(p[1]); | |
333 | fatal("Couldn't fork: %s", strerror(errno)); | |
334 | /* NOTREACHED */ | |
335 | case 0: /* Child */ | |
336 | dup2(devnull, STDIN_FILENO); | |
337 | dup2(p[1], STDOUT_FILENO); | |
338 | dup2(p[1], STDERR_FILENO); | |
339 | close(p[0]); | |
340 | close(p[1]); | |
341 | close(devnull); | |
342 | ||
343 | execv(src->path, (char**)(src->args)); | |
40f64e6f | 344 | |
aff51935 | 345 | debug("(child) Couldn't exec '%s': %s", |
40f64e6f | 346 | src->cmdstring, strerror(errno)); |
46058ce2 | 347 | _exit(-1); |
348 | default: /* Parent */ | |
349 | break; | |
350 | } | |
351 | ||
352 | RAND_add(&pid, sizeof(&pid), 0.0); | |
353 | ||
354 | close(p[1]); | |
355 | ||
356 | /* Hash output from child */ | |
357 | SHA1_Init(&sha); | |
46058ce2 | 358 | |
40f64e6f | 359 | cmd_eof = error_abort = msec_elapsed = total_bytes_read = 0; |
46058ce2 | 360 | while (!error_abort && !cmd_eof) { |
361 | int ret; | |
362 | struct timeval tv; | |
363 | int msec_remaining; | |
364 | ||
365 | (void) gettimeofday(&tv_current, 0); | |
40f64e6f | 366 | msec_elapsed = timeval_diff(&tv_start, &tv_current); |
46058ce2 | 367 | if (msec_elapsed >= entropy_timeout_current) { |
368 | error_abort=1; | |
369 | continue; | |
370 | } | |
371 | msec_remaining = entropy_timeout_current - msec_elapsed; | |
372 | ||
373 | FD_ZERO(&rdset); | |
374 | FD_SET(p[0], &rdset); | |
40f64e6f | 375 | tv.tv_sec = msec_remaining / 1000; |
46058ce2 | 376 | tv.tv_usec = (msec_remaining % 1000) * 1000; |
377 | ||
40f64e6f | 378 | ret = select(p[0] + 1, &rdset, NULL, NULL, &tv); |
46058ce2 | 379 | |
380 | RAND_add(&tv, sizeof(tv), 0.0); | |
381 | ||
382 | switch (ret) { | |
383 | case 0: | |
384 | /* timer expired */ | |
385 | error_abort = 1; | |
4e6f1c4f | 386 | kill(pid, SIGINT); |
46058ce2 | 387 | break; |
388 | case 1: | |
389 | /* command input */ | |
390 | do { | |
391 | bytes_read = read(p[0], buf, sizeof(buf)); | |
392 | } while (bytes_read == -1 && errno == EINTR); | |
393 | RAND_add(&bytes_read, sizeof(&bytes_read), 0.0); | |
394 | if (bytes_read == -1) { | |
395 | error_abort = 1; | |
396 | break; | |
397 | } else if (bytes_read) { | |
398 | SHA1_Update(&sha, buf, bytes_read); | |
399 | total_bytes_read += bytes_read; | |
400 | } else { | |
401 | cmd_eof = 1; | |
402 | } | |
403 | break; | |
404 | case -1: | |
405 | default: | |
406 | /* error */ | |
aff51935 | 407 | debug("Command '%s': select() failed: %s", |
40f64e6f | 408 | src->cmdstring, strerror(errno)); |
46058ce2 | 409 | error_abort = 1; |
410 | break; | |
411 | } | |
412 | } | |
413 | ||
414 | SHA1_Final(hash, &sha); | |
415 | ||
416 | close(p[0]); | |
417 | ||
418 | debug3("Time elapsed: %d msec", msec_elapsed); | |
419 | ||
420 | if (waitpid(pid, &status, 0) == -1) { | |
98c044d0 | 421 | error("Couldn't wait for child '%s' completion: %s", |
422 | src->cmdstring, strerror(errno)); | |
40f64e6f | 423 | return 0.0; |
46058ce2 | 424 | } |
425 | ||
426 | RAND_add(&status, sizeof(&status), 0.0); | |
427 | ||
428 | if (error_abort) { | |
40f64e6f | 429 | /* |
430 | * Closing p[0] on timeout causes the entropy command to | |
aff51935 | 431 | * SIGPIPE. Take whatever output we got, and mark this |
432 | * command as slow | |
40f64e6f | 433 | */ |
46058ce2 | 434 | debug2("Command '%s' timed out", src->cmdstring); |
435 | src->sticky_badness *= 2; | |
436 | src->badness = src->sticky_badness; | |
40f64e6f | 437 | return total_bytes_read; |
46058ce2 | 438 | } |
439 | ||
440 | if (WIFEXITED(status)) { | |
40f64e6f | 441 | if (WEXITSTATUS(status) == 0) { |
442 | return total_bytes_read; | |
46058ce2 | 443 | } else { |
40f64e6f | 444 | debug2("Command '%s' exit status was %d", |
445 | src->cmdstring, WEXITSTATUS(status)); | |
46058ce2 | 446 | src->badness = src->sticky_badness = 128; |
40f64e6f | 447 | return 0.0; |
46058ce2 | 448 | } |
449 | } else if (WIFSIGNALED(status)) { | |
40f64e6f | 450 | debug2("Command '%s' returned on uncaught signal %d !", |
451 | src->cmdstring, status); | |
46058ce2 | 452 | src->badness = src->sticky_badness = 128; |
40f64e6f | 453 | return 0.0; |
46058ce2 | 454 | } else |
40f64e6f | 455 | return 0.0; |
456 | } | |
457 | ||
458 | double | |
459 | stir_from_system(void) | |
460 | { | |
461 | double total_entropy_estimate; | |
462 | long int i; | |
463 | ||
464 | total_entropy_estimate = 0; | |
465 | ||
466 | i = getpid(); | |
467 | RAND_add(&i, sizeof(i), 0.5); | |
468 | total_entropy_estimate += 0.1; | |
469 | ||
470 | i = getppid(); | |
471 | RAND_add(&i, sizeof(i), 0.5); | |
472 | total_entropy_estimate += 0.1; | |
473 | ||
474 | i = getuid(); | |
475 | RAND_add(&i, sizeof(i), 0.0); | |
476 | i = getgid(); | |
477 | RAND_add(&i, sizeof(i), 0.0); | |
478 | ||
479 | total_entropy_estimate += stir_gettimeofday(1.0); | |
480 | total_entropy_estimate += stir_clock(0.5); | |
481 | total_entropy_estimate += stir_rusage(RUSAGE_SELF, 2.0); | |
482 | ||
483 | return total_entropy_estimate; | |
484 | } | |
485 | ||
486 | double | |
487 | stir_from_programs(void) | |
488 | { | |
489 | int c; | |
490 | double entropy, total_entropy; | |
75131bbd | 491 | unsigned char hash[SHA_DIGEST_LENGTH]; |
40f64e6f | 492 | |
493 | total_entropy = 0; | |
494 | for(c = 0; entropy_cmds[c].path != NULL; c++) { | |
495 | if (!entropy_cmds[c].badness) { | |
496 | /* Hash output from command */ | |
497 | entropy = hash_command_output(&entropy_cmds[c], | |
498 | hash); | |
499 | ||
500 | /* Scale back estimate by command's rate */ | |
501 | entropy *= entropy_cmds[c].rate; | |
502 | ||
503 | /* Upper bound of entropy is SHA_DIGEST_LENGTH */ | |
504 | if (entropy > SHA_DIGEST_LENGTH) | |
505 | entropy = SHA_DIGEST_LENGTH; | |
506 | ||
507 | /* Stir it in */ | |
508 | RAND_add(hash, sizeof(hash), entropy); | |
509 | ||
aff51935 | 510 | debug3("Got %0.2f bytes of entropy from '%s'", |
40f64e6f | 511 | entropy, entropy_cmds[c].cmdstring); |
512 | ||
513 | total_entropy += entropy; | |
514 | ||
515 | /* Execution time should be a bit unpredictable */ | |
516 | total_entropy += stir_gettimeofday(0.05); | |
517 | total_entropy += stir_clock(0.05); | |
518 | total_entropy += stir_rusage(RUSAGE_SELF, 0.1); | |
519 | total_entropy += stir_rusage(RUSAGE_CHILDREN, 0.1); | |
520 | } else { | |
521 | debug2("Command '%s' disabled (badness %d)", | |
aff51935 | 522 | entropy_cmds[c].cmdstring, |
40f64e6f | 523 | entropy_cmds[c].badness); |
524 | ||
525 | if (entropy_cmds[c].badness > 0) | |
526 | entropy_cmds[c].badness--; | |
527 | } | |
528 | } | |
529 | ||
530 | return total_entropy; | |
46058ce2 | 531 | } |
532 | ||
533 | /* | |
534 | * prng seedfile functions | |
535 | */ | |
536 | int | |
40f64e6f | 537 | prng_check_seedfile(char *filename) |
538 | { | |
46058ce2 | 539 | struct stat st; |
540 | ||
40f64e6f | 541 | /* |
aff51935 | 542 | * XXX raceable: eg replace seed between this stat and subsequent |
543 | * open. Not such a problem because we don't really trust the | |
40f64e6f | 544 | * seed file anyway. |
545 | * XXX: use secure path checking as elsewhere in OpenSSH | |
546 | */ | |
46058ce2 | 547 | if (lstat(filename, &st) == -1) { |
548 | /* Give up on hard errors */ | |
549 | if (errno != ENOENT) | |
40f64e6f | 550 | debug("WARNING: Couldn't stat random seed file " |
551 | "\"%.100s\": %s", filename, strerror(errno)); | |
552 | return 0; | |
46058ce2 | 553 | } |
554 | ||
555 | /* regular file? */ | |
556 | if (!S_ISREG(st.st_mode)) | |
40f64e6f | 557 | fatal("PRNG seedfile %.100s is not a regular file", |
558 | filename); | |
46058ce2 | 559 | |
560 | /* mode 0600, owned by root or the current user? */ | |
561 | if (((st.st_mode & 0177) != 0) || !(st.st_uid == getuid())) { | |
40f64e6f | 562 | debug("WARNING: PRNG seedfile %.100s must be mode 0600, " |
7be625e1 | 563 | "owned by uid %li", filename, (long int)getuid()); |
40f64e6f | 564 | return 0; |
46058ce2 | 565 | } |
566 | ||
40f64e6f | 567 | return 1; |
46058ce2 | 568 | } |
569 | ||
570 | void | |
40f64e6f | 571 | prng_write_seedfile(void) |
572 | { | |
a418076b | 573 | int fd, save_errno; |
75131bbd | 574 | unsigned char seed[SEED_FILE_SIZE]; |
a418076b | 575 | char filename[MAXPATHLEN], tmpseed[MAXPATHLEN]; |
46058ce2 | 576 | struct passwd *pw; |
a418076b | 577 | mode_t old_umask; |
46058ce2 | 578 | |
579 | pw = getpwuid(getuid()); | |
580 | if (pw == NULL) | |
40f64e6f | 581 | fatal("Couldn't get password entry for current user " |
7be625e1 | 582 | "(%li): %s", (long int)getuid(), strerror(errno)); |
46058ce2 | 583 | |
584 | /* Try to ensure that the parent directory is there */ | |
585 | snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir, | |
40f64e6f | 586 | _PATH_SSH_USER_DIR); |
e5c27607 | 587 | if (mkdir(filename, 0700) < 0 && errno != EEXIST) |
588 | fatal("mkdir %.200s: %s", filename, strerror(errno)); | |
46058ce2 | 589 | |
590 | snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir, | |
40f64e6f | 591 | SSH_PRNG_SEED_FILE); |
46058ce2 | 592 | |
a418076b | 593 | strlcpy(tmpseed, filename, sizeof(tmpseed)); |
594 | if (strlcat(tmpseed, ".XXXXXXXXXX", sizeof(tmpseed)) >= | |
595 | sizeof(tmpseed)) | |
596 | fatal("PRNG seed filename too long"); | |
46058ce2 | 597 | |
d8eb5247 | 598 | if (RAND_bytes(seed, sizeof(seed)) <= 0) |
9e3191db | 599 | fatal("PRNG seed extraction failed"); |
46058ce2 | 600 | |
601 | /* Don't care if the seed doesn't exist */ | |
602 | prng_check_seedfile(filename); | |
603 | ||
a418076b | 604 | old_umask = umask(0177); |
605 | ||
606 | if ((fd = mkstemp(tmpseed)) == -1) { | |
607 | debug("WARNING: couldn't make temporary PRNG seedfile %.100s " | |
608 | "(%.100s)", tmpseed, strerror(errno)); | |
46058ce2 | 609 | } else { |
a418076b | 610 | debug("writing PRNG seed to file %.100s", tmpseed); |
611 | if (atomicio(vwrite, fd, &seed, sizeof(seed)) < sizeof(seed)) { | |
612 | save_errno = errno; | |
613 | close(fd); | |
614 | unlink(tmpseed); | |
40f64e6f | 615 | fatal("problem writing PRNG seedfile %.100s " |
a418076b | 616 | "(%.100s)", filename, strerror(save_errno)); |
617 | } | |
46058ce2 | 618 | close(fd); |
a418076b | 619 | debug("moving temporary PRNG seed to file %.100s", filename); |
620 | if (rename(tmpseed, filename) == -1) { | |
621 | save_errno = errno; | |
622 | unlink(tmpseed); | |
623 | fatal("problem renaming PRNG seedfile from %.100s " | |
d1cf9a87 | 624 | "to %.100s (%.100s)", tmpseed, filename, |
a418076b | 625 | strerror(save_errno)); |
626 | } | |
46058ce2 | 627 | } |
a418076b | 628 | umask(old_umask); |
46058ce2 | 629 | } |
630 | ||
631 | void | |
40f64e6f | 632 | prng_read_seedfile(void) |
633 | { | |
46058ce2 | 634 | int fd; |
40f64e6f | 635 | char seed[SEED_FILE_SIZE], filename[MAXPATHLEN]; |
46058ce2 | 636 | struct passwd *pw; |
637 | ||
638 | pw = getpwuid(getuid()); | |
639 | if (pw == NULL) | |
40f64e6f | 640 | fatal("Couldn't get password entry for current user " |
7be625e1 | 641 | "(%li): %s", (long int)getuid(), strerror(errno)); |
46058ce2 | 642 | |
643 | snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir, | |
644 | SSH_PRNG_SEED_FILE); | |
645 | ||
646 | debug("loading PRNG seed from file %.100s", filename); | |
647 | ||
648 | if (!prng_check_seedfile(filename)) { | |
40f64e6f | 649 | verbose("Random seed file not found or invalid, ignoring."); |
46058ce2 | 650 | return; |
651 | } | |
652 | ||
653 | /* open the file and read in the seed */ | |
654 | fd = open(filename, O_RDONLY); | |
655 | if (fd == -1) | |
40f64e6f | 656 | fatal("could not open PRNG seedfile %.100s (%.100s)", |
657 | filename, strerror(errno)); | |
46058ce2 | 658 | |
40f64e6f | 659 | if (atomicio(read, fd, &seed, sizeof(seed)) < sizeof(seed)) { |
660 | verbose("invalid or short read from PRNG seedfile " | |
661 | "%.100s - ignoring", filename); | |
46058ce2 | 662 | memset(seed, '\0', sizeof(seed)); |
663 | } | |
664 | close(fd); | |
665 | ||
666 | /* stir in the seed, with estimated entropy zero */ | |
667 | RAND_add(&seed, sizeof(seed), 0.0); | |
668 | } | |
669 | ||
670 | ||
671 | /* | |
672 | * entropy command initialisation functions | |
673 | */ | |
674 | int | |
675 | prng_read_commands(char *cmdfilename) | |
676 | { | |
40f64e6f | 677 | char cmd[SEED_FILE_SIZE], *cp, line[1024], path[SEED_FILE_SIZE]; |
46058ce2 | 678 | double est; |
40f64e6f | 679 | entropy_cmd_t *entcmd; |
680 | FILE *f; | |
681 | int cur_cmd, linenum, num_cmds, arg; | |
46058ce2 | 682 | |
40f64e6f | 683 | if ((f = fopen(cmdfilename, "r")) == NULL) { |
46058ce2 | 684 | fatal("couldn't read entropy commands file %.100s: %.100s", |
685 | cmdfilename, strerror(errno)); | |
686 | } | |
687 | ||
40f64e6f | 688 | num_cmds = 64; |
01d35895 | 689 | entcmd = xcalloc(num_cmds, sizeof(entropy_cmd_t)); |
46058ce2 | 690 | |
691 | /* Read in file */ | |
40f64e6f | 692 | cur_cmd = linenum = 0; |
46058ce2 | 693 | while (fgets(line, sizeof(line), f)) { |
46058ce2 | 694 | linenum++; |
695 | ||
40f64e6f | 696 | /* Skip leading whitespace, blank lines and comments */ |
46058ce2 | 697 | cp = line + strspn(line, WHITESPACE); |
698 | if ((*cp == 0) || (*cp == '#')) | |
699 | continue; /* done with this line */ | |
700 | ||
40f64e6f | 701 | /* |
aff51935 | 702 | * The first non-whitespace char should be a double quote |
40f64e6f | 703 | * delimiting the commandline |
704 | */ | |
46058ce2 | 705 | if (*cp != '"') { |
40f64e6f | 706 | error("bad entropy command, %.100s line %d", |
707 | cmdfilename, linenum); | |
46058ce2 | 708 | continue; |
709 | } | |
710 | ||
40f64e6f | 711 | /* |
712 | * First token, command args (incl. argv[0]) in double | |
713 | * quotes | |
714 | */ | |
46058ce2 | 715 | cp = strtok(cp, "\""); |
716 | if (cp == NULL) { | |
40f64e6f | 717 | error("missing or bad command string, %.100s " |
718 | "line %d -- ignored", cmdfilename, linenum); | |
46058ce2 | 719 | continue; |
720 | } | |
721 | strlcpy(cmd, cp, sizeof(cmd)); | |
722 | ||
40f64e6f | 723 | /* Second token, full command path */ |
46058ce2 | 724 | if ((cp = strtok(NULL, WHITESPACE)) == NULL) { |
40f64e6f | 725 | error("missing command path, %.100s " |
726 | "line %d -- ignored", cmdfilename, linenum); | |
46058ce2 | 727 | continue; |
728 | } | |
729 | ||
40f64e6f | 730 | /* Did configure mark this as dead? */ |
46058ce2 | 731 | if (strncmp("undef", cp, 5) == 0) |
732 | continue; | |
733 | ||
734 | strlcpy(path, cp, sizeof(path)); | |
735 | ||
40f64e6f | 736 | /* Third token, entropy rate estimate for this command */ |
46058ce2 | 737 | if ((cp = strtok(NULL, WHITESPACE)) == NULL) { |
40f64e6f | 738 | error("missing entropy estimate, %.100s " |
739 | "line %d -- ignored", cmdfilename, linenum); | |
46058ce2 | 740 | continue; |
741 | } | |
40f64e6f | 742 | est = strtod(cp, NULL); |
46058ce2 | 743 | |
744 | /* end of line */ | |
745 | if ((cp = strtok(NULL, WHITESPACE)) != NULL) { | |
40f64e6f | 746 | error("garbage at end of line %d in %.100s " |
747 | "-- ignored", linenum, cmdfilename); | |
46058ce2 | 748 | continue; |
749 | } | |
750 | ||
751 | /* save the command for debug messages */ | |
752 | entcmd[cur_cmd].cmdstring = xstrdup(cmd); | |
753 | ||
754 | /* split the command args */ | |
755 | cp = strtok(cmd, WHITESPACE); | |
756 | arg = 0; | |
46058ce2 | 757 | do { |
40f64e6f | 758 | entcmd[cur_cmd].args[arg] = xstrdup(cp); |
46058ce2 | 759 | arg++; |
40f64e6f | 760 | } while(arg < NUM_ARGS && (cp = strtok(NULL, WHITESPACE))); |
46058ce2 | 761 | |
762 | if (strtok(NULL, WHITESPACE)) | |
40f64e6f | 763 | error("ignored extra commands (max %d), %.100s " |
764 | "line %d", NUM_ARGS, cmdfilename, linenum); | |
46058ce2 | 765 | |
766 | /* Copy the command path and rate estimate */ | |
767 | entcmd[cur_cmd].path = xstrdup(path); | |
768 | entcmd[cur_cmd].rate = est; | |
769 | ||
770 | /* Initialise other values */ | |
771 | entcmd[cur_cmd].sticky_badness = 1; | |
772 | ||
773 | cur_cmd++; | |
774 | ||
40f64e6f | 775 | /* |
776 | * If we've filled the array, reallocate it twice the size | |
aff51935 | 777 | * Do this now because even if this we're on the last |
40f64e6f | 778 | * command we need another slot to mark the last entry |
779 | */ | |
46058ce2 | 780 | if (cur_cmd == num_cmds) { |
781 | num_cmds *= 2; | |
c5d10563 | 782 | entcmd = xrealloc(entcmd, num_cmds, |
40f64e6f | 783 | sizeof(entropy_cmd_t)); |
46058ce2 | 784 | } |
785 | } | |
786 | ||
787 | /* zero the last entry */ | |
40f64e6f | 788 | memset(&entcmd[cur_cmd], '\0', sizeof(entropy_cmd_t)); |
46058ce2 | 789 | |
790 | /* trim to size */ | |
c5d10563 | 791 | entropy_cmds = xrealloc(entcmd, (cur_cmd + 1), |
40f64e6f | 792 | sizeof(entropy_cmd_t)); |
46058ce2 | 793 | |
40f64e6f | 794 | debug("Loaded %d entropy commands from %.100s", cur_cmd, |
795 | cmdfilename); | |
46058ce2 | 796 | |
aee28e67 | 797 | fclose(f); |
40f64e6f | 798 | return cur_cmd < MIN_ENTROPY_SOURCES ? -1 : 0; |
46058ce2 | 799 | } |
800 | ||
f6e6303d | 801 | void |
802 | usage(void) | |
803 | { | |
804 | fprintf(stderr, "Usage: %s [options]\n", __progname); | |
805 | fprintf(stderr, " -v Verbose; display verbose debugging messages.\n"); | |
806 | fprintf(stderr, " Multiple -v increases verbosity.\n"); | |
96b0de7d | 807 | fprintf(stderr, " -x Force output in hexadecimal (for debugging)\n"); |
f6e6303d | 808 | fprintf(stderr, " -X Force output in binary\n"); |
809 | fprintf(stderr, " -b bytes Number of bytes to output (default %d)\n", | |
810 | OUTPUT_SEED_SIZE); | |
811 | } | |
812 | ||
aff51935 | 813 | int |
46058ce2 | 814 | main(int argc, char **argv) |
815 | { | |
f6e6303d | 816 | unsigned char *buf; |
817 | int ret, ch, debug_level, output_hex, bytes; | |
818 | extern char *optarg; | |
819 | LogLevel ll; | |
46058ce2 | 820 | |
fda04d7d | 821 | __progname = ssh_get_progname(argv[0]); |
46058ce2 | 822 | log_init(argv[0], SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_USER, 1); |
823 | ||
f6e6303d | 824 | ll = SYSLOG_LEVEL_INFO; |
825 | debug_level = output_hex = 0; | |
826 | bytes = OUTPUT_SEED_SIZE; | |
827 | ||
828 | /* Don't write binary data to a tty, unless we are forced to */ | |
829 | if (isatty(STDOUT_FILENO)) | |
830 | output_hex = 1; | |
b6453d99 | 831 | |
f6e6303d | 832 | while ((ch = getopt(argc, argv, "vxXhb:")) != -1) { |
833 | switch (ch) { | |
834 | case 'v': | |
835 | if (debug_level < 3) | |
836 | ll = SYSLOG_LEVEL_DEBUG1 + debug_level++; | |
837 | break; | |
838 | case 'x': | |
839 | output_hex = 1; | |
840 | break; | |
841 | case 'X': | |
842 | output_hex = 0; | |
843 | break; | |
844 | case 'b': | |
845 | if ((bytes = atoi(optarg)) <= 0) | |
846 | fatal("Invalid number of output bytes"); | |
847 | break; | |
848 | case 'h': | |
849 | usage(); | |
850 | exit(0); | |
851 | default: | |
852 | error("Invalid commandline option"); | |
853 | usage(); | |
854 | } | |
855 | } | |
856 | ||
857 | log_init(argv[0], ll, SYSLOG_FACILITY_USER, 1); | |
b6453d99 | 858 | |
40f64e6f | 859 | #ifdef USE_SEED_FILES |
860 | prng_read_seedfile(); | |
861 | #endif | |
862 | ||
f6e6303d | 863 | buf = xmalloc(bytes); |
864 | ||
40f64e6f | 865 | /* |
866 | * Seed the RNG from wherever we can | |
867 | */ | |
b6453d99 | 868 | |
40f64e6f | 869 | /* Take whatever is on the stack, but don't credit it */ |
f6e6303d | 870 | RAND_add(buf, bytes, 0); |
40f64e6f | 871 | |
aff51935 | 872 | debug("Seeded RNG with %i bytes from system calls", |
40f64e6f | 873 | (int)stir_from_system()); |
874 | ||
1e111f05 | 875 | /* try prngd, fall back to commands if prngd fails or not configured */ |
876 | if (seed_from_prngd(buf, bytes) == 0) { | |
877 | RAND_add(buf, bytes, bytes); | |
878 | } else { | |
879 | /* Read in collection commands */ | |
880 | if (prng_read_commands(SSH_PRNG_COMMAND_FILE) == -1) | |
881 | fatal("PRNG initialisation failed -- exiting."); | |
882 | debug("Seeded RNG with %i bytes from programs", | |
883 | (int)stir_from_programs()); | |
884 | } | |
40f64e6f | 885 | |
886 | #ifdef USE_SEED_FILES | |
887 | prng_write_seedfile(); | |
888 | #endif | |
889 | ||
890 | /* | |
891 | * Write the seed to stdout | |
892 | */ | |
46058ce2 | 893 | |
894 | if (!RAND_status()) | |
895 | fatal("Not enough entropy in RNG"); | |
896 | ||
d8eb5247 | 897 | if (RAND_bytes(buf, bytes) <= 0) |
898 | fatal("Couldn't extract entropy from PRNG"); | |
46058ce2 | 899 | |
f6e6303d | 900 | if (output_hex) { |
901 | for(ret = 0; ret < bytes; ret++) | |
902 | printf("%02x", (unsigned char)(buf[ret])); | |
903 | printf("\n"); | |
904 | } else | |
d72f7b79 | 905 | ret = atomicio(vwrite, STDOUT_FILENO, buf, bytes); |
b6453d99 | 906 | |
f6e6303d | 907 | memset(buf, '\0', bytes); |
908 | xfree(buf); | |
b6453d99 | 909 | |
f6e6303d | 910 | return ret == bytes ? 0 : 1; |
46058ce2 | 911 | } |
e005a96c | 912 | |
913 | /* | |
914 | * We may attempt to re-seed during mkstemp if we are using the one in the | |
759c7b91 | 915 | * compat library (via mkstemp -> _gettemp -> arc4random -> seed_rng) so we |
916 | * need our own seed_rng(). We must also check that we have enough entropy. | |
e005a96c | 917 | */ |
918 | void | |
919 | seed_rng(void) | |
920 | { | |
921 | if (!RAND_status()) | |
922 | fatal("Not enough entropy in RNG"); | |
923 | } |