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