diff options
author | Colin Watson <cjwatson@debian.org> | 2011-09-06 09:45:52 +0100 |
---|---|---|
committer | Colin Watson <cjwatson@debian.org> | 2011-09-06 09:45:52 +0100 |
commit | f38224d546cdde55f45c13d3d8225d273a3f920e (patch) | |
tree | a91a26b88ac90dc72d0ea3767feabb341eaa50a8 /ssh-rand-helper.c | |
parent | 338146a3fc257e216fe5c10fe40e6896b40d7739 (diff) | |
parent | e90790abaf031e037f444a6658e136e48577ea49 (diff) |
merge 5.9p1
Diffstat (limited to 'ssh-rand-helper.c')
-rw-r--r-- | ssh-rand-helper.c | 932 |
1 files changed, 0 insertions, 932 deletions
diff --git a/ssh-rand-helper.c b/ssh-rand-helper.c deleted file mode 100644 index fa5070499..000000000 --- a/ssh-rand-helper.c +++ /dev/null | |||
@@ -1,932 +0,0 @@ | |||
1 | /* | ||
2 | * Copyright (c) 2001-2002 Damien Miller. All rights reserved. | ||
3 | * | ||
4 | * Redistribution and use in source and binary forms, with or without | ||
5 | * modification, are permitted provided that the following conditions | ||
6 | * are met: | ||
7 | * 1. Redistributions of source code must retain the above copyright | ||
8 | * notice, this list of conditions and the following disclaimer. | ||
9 | * 2. Redistributions in binary form must reproduce the above copyright | ||
10 | * notice, this list of conditions and the following disclaimer in the | ||
11 | * documentation and/or other materials provided with the distribution. | ||
12 | * | ||
13 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR | ||
14 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES | ||
15 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. | ||
16 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, | ||
17 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | ||
18 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | ||
19 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | ||
20 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | ||
21 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF | ||
22 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | ||
23 | */ | ||
24 | |||
25 | #include "includes.h" | ||
26 | |||
27 | #include <sys/types.h> | ||
28 | #include <sys/resource.h> | ||
29 | #include <sys/stat.h> | ||
30 | #include <sys/wait.h> | ||
31 | #include <sys/socket.h> | ||
32 | |||
33 | #include <stdarg.h> | ||
34 | #include <stddef.h> | ||
35 | #include <string.h> | ||
36 | |||
37 | #include <netinet/in.h> | ||
38 | #include <arpa/inet.h> | ||
39 | |||
40 | #ifdef HAVE_SYS_UN_H | ||
41 | # include <sys/un.h> | ||
42 | #endif | ||
43 | |||
44 | #include <errno.h> | ||
45 | #include <fcntl.h> | ||
46 | #include <pwd.h> | ||
47 | #include <signal.h> | ||
48 | #include <time.h> | ||
49 | #include <unistd.h> | ||
50 | |||
51 | #include <openssl/rand.h> | ||
52 | #include <openssl/sha.h> | ||
53 | #include <openssl/crypto.h> | ||
54 | |||
55 | /* SunOS 4.4.4 needs this */ | ||
56 | #ifdef HAVE_FLOATINGPOINT_H | ||
57 | # include <floatingpoint.h> | ||
58 | #endif /* HAVE_FLOATINGPOINT_H */ | ||
59 | |||
60 | #include "misc.h" | ||
61 | #include "xmalloc.h" | ||
62 | #include "atomicio.h" | ||
63 | #include "pathnames.h" | ||
64 | #include "log.h" | ||
65 | |||
66 | /* Number of bytes we write out */ | ||
67 | #define OUTPUT_SEED_SIZE 48 | ||
68 | |||
69 | /* Length of on-disk seedfiles */ | ||
70 | #define SEED_FILE_SIZE 1024 | ||
71 | |||
72 | /* Maximum number of command-line arguments to read from file */ | ||
73 | #define NUM_ARGS 10 | ||
74 | |||
75 | /* Minimum number of usable commands to be considered sufficient */ | ||
76 | #define MIN_ENTROPY_SOURCES 16 | ||
77 | |||
78 | /* Path to on-disk seed file (relative to user's home directory */ | ||
79 | #ifndef SSH_PRNG_SEED_FILE | ||
80 | # define SSH_PRNG_SEED_FILE _PATH_SSH_USER_DIR"/prng_seed" | ||
81 | #endif | ||
82 | |||
83 | /* Path to PRNG commands list */ | ||
84 | #ifndef SSH_PRNG_COMMAND_FILE | ||
85 | # define SSH_PRNG_COMMAND_FILE SSHDIR "/ssh_prng_cmds" | ||
86 | #endif | ||
87 | |||
88 | extern char *__progname; | ||
89 | |||
90 | #define WHITESPACE " \t\n" | ||
91 | |||
92 | #ifndef RUSAGE_SELF | ||
93 | # define RUSAGE_SELF 0 | ||
94 | #endif | ||
95 | #ifndef RUSAGE_CHILDREN | ||
96 | # define RUSAGE_CHILDREN 0 | ||
97 | #endif | ||
98 | |||
99 | #if !defined(PRNGD_SOCKET) && !defined(PRNGD_PORT) | ||
100 | # define USE_SEED_FILES | ||
101 | #endif | ||
102 | |||
103 | typedef struct { | ||
104 | /* Proportion of data that is entropy */ | ||
105 | double rate; | ||
106 | /* Counter goes positive if this command times out */ | ||
107 | unsigned int badness; | ||
108 | /* Increases by factor of two each timeout */ | ||
109 | unsigned int sticky_badness; | ||
110 | /* Path to executable */ | ||
111 | char *path; | ||
112 | /* argv to pass to executable */ | ||
113 | char *args[NUM_ARGS]; /* XXX: arbitrary limit */ | ||
114 | /* full command string (debug) */ | ||
115 | char *cmdstring; | ||
116 | } entropy_cmd_t; | ||
117 | |||
118 | /* slow command timeouts (all in milliseconds) */ | ||
119 | /* static int entropy_timeout_default = ENTROPY_TIMEOUT_MSEC; */ | ||
120 | static int entropy_timeout_current = ENTROPY_TIMEOUT_MSEC; | ||
121 | |||
122 | /* this is initialised from a file, by prng_read_commands() */ | ||
123 | static entropy_cmd_t *entropy_cmds = NULL; | ||
124 | |||
125 | /* Prototypes */ | ||
126 | double stir_from_system(void); | ||
127 | double stir_from_programs(void); | ||
128 | double stir_gettimeofday(double entropy_estimate); | ||
129 | double stir_clock(double entropy_estimate); | ||
130 | double stir_rusage(int who, double entropy_estimate); | ||
131 | double hash_command_output(entropy_cmd_t *src, unsigned char *hash); | ||
132 | int get_random_bytes_prngd(unsigned char *buf, int len, | ||
133 | unsigned short tcp_port, char *socket_path); | ||
134 | |||
135 | /* | ||
136 | * Collect 'len' bytes of entropy into 'buf' from PRNGD/EGD daemon | ||
137 | * listening either on 'tcp_port', or via Unix domain socket at * | ||
138 | * 'socket_path'. | ||
139 | * Either a non-zero tcp_port or a non-null socket_path must be | ||
140 | * supplied. | ||
141 | * Returns 0 on success, -1 on error | ||
142 | */ | ||
143 | int | ||
144 | get_random_bytes_prngd(unsigned char *buf, int len, | ||
145 | unsigned short tcp_port, char *socket_path) | ||
146 | { | ||
147 | int fd, addr_len, rval, errors; | ||
148 | u_char msg[2]; | ||
149 | struct sockaddr_storage addr; | ||
150 | struct sockaddr_in *addr_in = (struct sockaddr_in *)&addr; | ||
151 | struct sockaddr_un *addr_un = (struct sockaddr_un *)&addr; | ||
152 | mysig_t old_sigpipe; | ||
153 | |||
154 | /* Sanity checks */ | ||
155 | if (socket_path == NULL && tcp_port == 0) | ||
156 | fatal("You must specify a port or a socket"); | ||
157 | if (socket_path != NULL && | ||
158 | strlen(socket_path) >= sizeof(addr_un->sun_path)) | ||
159 | fatal("Random pool path is too long"); | ||
160 | if (len <= 0 || len > 255) | ||
161 | fatal("Too many bytes (%d) to read from PRNGD", len); | ||
162 | |||
163 | memset(&addr, '\0', sizeof(addr)); | ||
164 | |||
165 | if (tcp_port != 0) { | ||
166 | addr_in->sin_family = AF_INET; | ||
167 | addr_in->sin_addr.s_addr = htonl(INADDR_LOOPBACK); | ||
168 | addr_in->sin_port = htons(tcp_port); | ||
169 | addr_len = sizeof(*addr_in); | ||
170 | } else { | ||
171 | addr_un->sun_family = AF_UNIX; | ||
172 | strlcpy(addr_un->sun_path, socket_path, | ||
173 | sizeof(addr_un->sun_path)); | ||
174 | addr_len = offsetof(struct sockaddr_un, sun_path) + | ||
175 | strlen(socket_path) + 1; | ||
176 | } | ||
177 | |||
178 | old_sigpipe = mysignal(SIGPIPE, SIG_IGN); | ||
179 | |||
180 | errors = 0; | ||
181 | rval = -1; | ||
182 | reopen: | ||
183 | fd = socket(addr.ss_family, SOCK_STREAM, 0); | ||
184 | if (fd == -1) { | ||
185 | error("Couldn't create socket: %s", strerror(errno)); | ||
186 | goto done; | ||
187 | } | ||
188 | |||
189 | if (connect(fd, (struct sockaddr*)&addr, addr_len) == -1) { | ||
190 | if (tcp_port != 0) { | ||
191 | error("Couldn't connect to PRNGD port %d: %s", | ||
192 | tcp_port, strerror(errno)); | ||
193 | } else { | ||
194 | error("Couldn't connect to PRNGD socket \"%s\": %s", | ||
195 | addr_un->sun_path, strerror(errno)); | ||
196 | } | ||
197 | goto done; | ||
198 | } | ||
199 | |||
200 | /* Send blocking read request to PRNGD */ | ||
201 | msg[0] = 0x02; | ||
202 | msg[1] = len; | ||
203 | |||
204 | if (atomicio(vwrite, fd, msg, sizeof(msg)) != sizeof(msg)) { | ||
205 | if (errno == EPIPE && errors < 10) { | ||
206 | close(fd); | ||
207 | errors++; | ||
208 | goto reopen; | ||
209 | } | ||
210 | error("Couldn't write to PRNGD socket: %s", | ||
211 | strerror(errno)); | ||
212 | goto done; | ||
213 | } | ||
214 | |||
215 | if (atomicio(read, fd, buf, len) != (size_t)len) { | ||
216 | if (errno == EPIPE && errors < 10) { | ||
217 | close(fd); | ||
218 | errors++; | ||
219 | goto reopen; | ||
220 | } | ||
221 | error("Couldn't read from PRNGD socket: %s", | ||
222 | strerror(errno)); | ||
223 | goto done; | ||
224 | } | ||
225 | |||
226 | rval = 0; | ||
227 | done: | ||
228 | mysignal(SIGPIPE, old_sigpipe); | ||
229 | if (fd != -1) | ||
230 | close(fd); | ||
231 | return rval; | ||
232 | } | ||
233 | |||
234 | static int | ||
235 | seed_from_prngd(unsigned char *buf, size_t bytes) | ||
236 | { | ||
237 | #ifdef PRNGD_PORT | ||
238 | debug("trying egd/prngd port %d", PRNGD_PORT); | ||
239 | if (get_random_bytes_prngd(buf, bytes, PRNGD_PORT, NULL) == 0) | ||
240 | return 0; | ||
241 | #endif | ||
242 | #ifdef PRNGD_SOCKET | ||
243 | debug("trying egd/prngd socket %s", PRNGD_SOCKET); | ||
244 | if (get_random_bytes_prngd(buf, bytes, 0, PRNGD_SOCKET) == 0) | ||
245 | return 0; | ||
246 | #endif | ||
247 | return -1; | ||
248 | } | ||
249 | |||
250 | double | ||
251 | stir_gettimeofday(double entropy_estimate) | ||
252 | { | ||
253 | struct timeval tv; | ||
254 | |||
255 | if (gettimeofday(&tv, NULL) == -1) | ||
256 | fatal("Couldn't gettimeofday: %s", strerror(errno)); | ||
257 | |||
258 | RAND_add(&tv, sizeof(tv), entropy_estimate); | ||
259 | |||
260 | return entropy_estimate; | ||
261 | } | ||
262 | |||
263 | double | ||
264 | stir_clock(double entropy_estimate) | ||
265 | { | ||
266 | #ifdef HAVE_CLOCK | ||
267 | clock_t c; | ||
268 | |||
269 | c = clock(); | ||
270 | RAND_add(&c, sizeof(c), entropy_estimate); | ||
271 | |||
272 | return entropy_estimate; | ||
273 | #else /* _HAVE_CLOCK */ | ||
274 | return 0; | ||
275 | #endif /* _HAVE_CLOCK */ | ||
276 | } | ||
277 | |||
278 | double | ||
279 | stir_rusage(int who, double entropy_estimate) | ||
280 | { | ||
281 | #ifdef HAVE_GETRUSAGE | ||
282 | struct rusage ru; | ||
283 | |||
284 | if (getrusage(who, &ru) == -1) | ||
285 | return 0; | ||
286 | |||
287 | RAND_add(&ru, sizeof(ru), entropy_estimate); | ||
288 | |||
289 | return entropy_estimate; | ||
290 | #else /* _HAVE_GETRUSAGE */ | ||
291 | return 0; | ||
292 | #endif /* _HAVE_GETRUSAGE */ | ||
293 | } | ||
294 | |||
295 | static int | ||
296 | timeval_diff(struct timeval *t1, struct timeval *t2) | ||
297 | { | ||
298 | int secdiff, usecdiff; | ||
299 | |||
300 | secdiff = t2->tv_sec - t1->tv_sec; | ||
301 | usecdiff = (secdiff*1000000) + (t2->tv_usec - t1->tv_usec); | ||
302 | return (int)(usecdiff / 1000); | ||
303 | } | ||
304 | |||
305 | double | ||
306 | hash_command_output(entropy_cmd_t *src, unsigned char *hash) | ||
307 | { | ||
308 | char buf[8192]; | ||
309 | fd_set rdset; | ||
310 | int bytes_read, cmd_eof, error_abort, msec_elapsed, p[2]; | ||
311 | int status, total_bytes_read; | ||
312 | static int devnull = -1; | ||
313 | pid_t pid; | ||
314 | SHA_CTX sha; | ||
315 | struct timeval tv_start, tv_current; | ||
316 | |||
317 | debug3("Reading output from \'%s\'", src->cmdstring); | ||
318 | |||
319 | if (devnull == -1) { | ||
320 | devnull = open("/dev/null", O_RDWR); | ||
321 | if (devnull == -1) | ||
322 | fatal("Couldn't open /dev/null: %s", | ||
323 | strerror(errno)); | ||
324 | } | ||
325 | |||
326 | if (pipe(p) == -1) | ||
327 | fatal("Couldn't open pipe: %s", strerror(errno)); | ||
328 | |||
329 | (void)gettimeofday(&tv_start, NULL); /* record start time */ | ||
330 | |||
331 | switch (pid = fork()) { | ||
332 | case -1: /* Error */ | ||
333 | close(p[0]); | ||
334 | close(p[1]); | ||
335 | fatal("Couldn't fork: %s", strerror(errno)); | ||
336 | /* NOTREACHED */ | ||
337 | case 0: /* Child */ | ||
338 | dup2(devnull, STDIN_FILENO); | ||
339 | dup2(p[1], STDOUT_FILENO); | ||
340 | dup2(p[1], STDERR_FILENO); | ||
341 | close(p[0]); | ||
342 | close(p[1]); | ||
343 | close(devnull); | ||
344 | |||
345 | execv(src->path, (char**)(src->args)); | ||
346 | |||
347 | debug("(child) Couldn't exec '%s': %s", | ||
348 | src->cmdstring, strerror(errno)); | ||
349 | _exit(-1); | ||
350 | default: /* Parent */ | ||
351 | break; | ||
352 | } | ||
353 | |||
354 | RAND_add(&pid, sizeof(&pid), 0.0); | ||
355 | |||
356 | close(p[1]); | ||
357 | |||
358 | /* Hash output from child */ | ||
359 | SHA1_Init(&sha); | ||
360 | |||
361 | cmd_eof = error_abort = msec_elapsed = total_bytes_read = 0; | ||
362 | while (!error_abort && !cmd_eof) { | ||
363 | int ret; | ||
364 | struct timeval tv; | ||
365 | int msec_remaining; | ||
366 | |||
367 | (void) gettimeofday(&tv_current, 0); | ||
368 | msec_elapsed = timeval_diff(&tv_start, &tv_current); | ||
369 | if (msec_elapsed >= entropy_timeout_current) { | ||
370 | error_abort=1; | ||
371 | continue; | ||
372 | } | ||
373 | msec_remaining = entropy_timeout_current - msec_elapsed; | ||
374 | |||
375 | FD_ZERO(&rdset); | ||
376 | FD_SET(p[0], &rdset); | ||
377 | tv.tv_sec = msec_remaining / 1000; | ||
378 | tv.tv_usec = (msec_remaining % 1000) * 1000; | ||
379 | |||
380 | ret = select(p[0] + 1, &rdset, NULL, NULL, &tv); | ||
381 | |||
382 | RAND_add(&tv, sizeof(tv), 0.0); | ||
383 | |||
384 | switch (ret) { | ||
385 | case 0: | ||
386 | /* timer expired */ | ||
387 | error_abort = 1; | ||
388 | kill(pid, SIGINT); | ||
389 | break; | ||
390 | case 1: | ||
391 | /* command input */ | ||
392 | do { | ||
393 | bytes_read = read(p[0], buf, sizeof(buf)); | ||
394 | } while (bytes_read == -1 && errno == EINTR); | ||
395 | RAND_add(&bytes_read, sizeof(&bytes_read), 0.0); | ||
396 | if (bytes_read == -1) { | ||
397 | error_abort = 1; | ||
398 | break; | ||
399 | } else if (bytes_read) { | ||
400 | SHA1_Update(&sha, buf, bytes_read); | ||
401 | total_bytes_read += bytes_read; | ||
402 | } else { | ||
403 | cmd_eof = 1; | ||
404 | } | ||
405 | break; | ||
406 | case -1: | ||
407 | default: | ||
408 | /* error */ | ||
409 | debug("Command '%s': select() failed: %s", | ||
410 | src->cmdstring, strerror(errno)); | ||
411 | error_abort = 1; | ||
412 | break; | ||
413 | } | ||
414 | } | ||
415 | |||
416 | SHA1_Final(hash, &sha); | ||
417 | |||
418 | close(p[0]); | ||
419 | |||
420 | debug3("Time elapsed: %d msec", msec_elapsed); | ||
421 | |||
422 | if (waitpid(pid, &status, 0) == -1) { | ||
423 | error("Couldn't wait for child '%s' completion: %s", | ||
424 | src->cmdstring, strerror(errno)); | ||
425 | return 0.0; | ||
426 | } | ||
427 | |||
428 | RAND_add(&status, sizeof(&status), 0.0); | ||
429 | |||
430 | if (error_abort) { | ||
431 | /* | ||
432 | * Closing p[0] on timeout causes the entropy command to | ||
433 | * SIGPIPE. Take whatever output we got, and mark this | ||
434 | * command as slow | ||
435 | */ | ||
436 | debug2("Command '%s' timed out", src->cmdstring); | ||
437 | src->sticky_badness *= 2; | ||
438 | src->badness = src->sticky_badness; | ||
439 | return total_bytes_read; | ||
440 | } | ||
441 | |||
442 | if (WIFEXITED(status)) { | ||
443 | if (WEXITSTATUS(status) == 0) { | ||
444 | return total_bytes_read; | ||
445 | } else { | ||
446 | debug2("Command '%s' exit status was %d", | ||
447 | src->cmdstring, WEXITSTATUS(status)); | ||
448 | src->badness = src->sticky_badness = 128; | ||
449 | return 0.0; | ||
450 | } | ||
451 | } else if (WIFSIGNALED(status)) { | ||
452 | debug2("Command '%s' returned on uncaught signal %d !", | ||
453 | src->cmdstring, status); | ||
454 | src->badness = src->sticky_badness = 128; | ||
455 | return 0.0; | ||
456 | } else | ||
457 | return 0.0; | ||
458 | } | ||
459 | |||
460 | double | ||
461 | stir_from_system(void) | ||
462 | { | ||
463 | double total_entropy_estimate; | ||
464 | long int i; | ||
465 | |||
466 | total_entropy_estimate = 0; | ||
467 | |||
468 | i = getpid(); | ||
469 | RAND_add(&i, sizeof(i), 0.5); | ||
470 | total_entropy_estimate += 0.1; | ||
471 | |||
472 | i = getppid(); | ||
473 | RAND_add(&i, sizeof(i), 0.5); | ||
474 | total_entropy_estimate += 0.1; | ||
475 | |||
476 | i = getuid(); | ||
477 | RAND_add(&i, sizeof(i), 0.0); | ||
478 | i = getgid(); | ||
479 | RAND_add(&i, sizeof(i), 0.0); | ||
480 | |||
481 | total_entropy_estimate += stir_gettimeofday(1.0); | ||
482 | total_entropy_estimate += stir_clock(0.5); | ||
483 | total_entropy_estimate += stir_rusage(RUSAGE_SELF, 2.0); | ||
484 | |||
485 | return total_entropy_estimate; | ||
486 | } | ||
487 | |||
488 | double | ||
489 | stir_from_programs(void) | ||
490 | { | ||
491 | int c; | ||
492 | double entropy, total_entropy; | ||
493 | unsigned char hash[SHA_DIGEST_LENGTH]; | ||
494 | |||
495 | total_entropy = 0; | ||
496 | for(c = 0; entropy_cmds[c].path != NULL; c++) { | ||
497 | if (!entropy_cmds[c].badness) { | ||
498 | /* Hash output from command */ | ||
499 | entropy = hash_command_output(&entropy_cmds[c], | ||
500 | hash); | ||
501 | |||
502 | /* Scale back estimate by command's rate */ | ||
503 | entropy *= entropy_cmds[c].rate; | ||
504 | |||
505 | /* Upper bound of entropy is SHA_DIGEST_LENGTH */ | ||
506 | if (entropy > SHA_DIGEST_LENGTH) | ||
507 | entropy = SHA_DIGEST_LENGTH; | ||
508 | |||
509 | /* Stir it in */ | ||
510 | RAND_add(hash, sizeof(hash), entropy); | ||
511 | |||
512 | debug3("Got %0.2f bytes of entropy from '%s'", | ||
513 | entropy, entropy_cmds[c].cmdstring); | ||
514 | |||
515 | total_entropy += entropy; | ||
516 | |||
517 | /* Execution time should be a bit unpredictable */ | ||
518 | total_entropy += stir_gettimeofday(0.05); | ||
519 | total_entropy += stir_clock(0.05); | ||
520 | total_entropy += stir_rusage(RUSAGE_SELF, 0.1); | ||
521 | total_entropy += stir_rusage(RUSAGE_CHILDREN, 0.1); | ||
522 | } else { | ||
523 | debug2("Command '%s' disabled (badness %d)", | ||
524 | entropy_cmds[c].cmdstring, | ||
525 | entropy_cmds[c].badness); | ||
526 | |||
527 | if (entropy_cmds[c].badness > 0) | ||
528 | entropy_cmds[c].badness--; | ||
529 | } | ||
530 | } | ||
531 | |||
532 | return total_entropy; | ||
533 | } | ||
534 | |||
535 | /* | ||
536 | * prng seedfile functions | ||
537 | */ | ||
538 | int | ||
539 | prng_check_seedfile(char *filename) | ||
540 | { | ||
541 | struct stat st; | ||
542 | |||
543 | /* | ||
544 | * XXX raceable: eg replace seed between this stat and subsequent | ||
545 | * open. Not such a problem because we don't really trust the | ||
546 | * seed file anyway. | ||
547 | * XXX: use secure path checking as elsewhere in OpenSSH | ||
548 | */ | ||
549 | if (lstat(filename, &st) == -1) { | ||
550 | /* Give up on hard errors */ | ||
551 | if (errno != ENOENT) | ||
552 | debug("WARNING: Couldn't stat random seed file " | ||
553 | "\"%.100s\": %s", filename, strerror(errno)); | ||
554 | return 0; | ||
555 | } | ||
556 | |||
557 | /* regular file? */ | ||
558 | if (!S_ISREG(st.st_mode)) | ||
559 | fatal("PRNG seedfile %.100s is not a regular file", | ||
560 | filename); | ||
561 | |||
562 | /* mode 0600, owned by root or the current user? */ | ||
563 | if (((st.st_mode & 0177) != 0) || !(st.st_uid == getuid())) { | ||
564 | debug("WARNING: PRNG seedfile %.100s must be mode 0600, " | ||
565 | "owned by uid %li", filename, (long int)getuid()); | ||
566 | return 0; | ||
567 | } | ||
568 | |||
569 | return 1; | ||
570 | } | ||
571 | |||
572 | void | ||
573 | prng_write_seedfile(void) | ||
574 | { | ||
575 | int fd, save_errno; | ||
576 | unsigned char seed[SEED_FILE_SIZE]; | ||
577 | char filename[MAXPATHLEN], tmpseed[MAXPATHLEN]; | ||
578 | struct passwd *pw; | ||
579 | mode_t old_umask; | ||
580 | |||
581 | pw = getpwuid(getuid()); | ||
582 | if (pw == NULL) | ||
583 | fatal("Couldn't get password entry for current user " | ||
584 | "(%li): %s", (long int)getuid(), strerror(errno)); | ||
585 | |||
586 | /* Try to ensure that the parent directory is there */ | ||
587 | snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir, | ||
588 | _PATH_SSH_USER_DIR); | ||
589 | if (mkdir(filename, 0700) < 0 && errno != EEXIST) | ||
590 | fatal("mkdir %.200s: %s", filename, strerror(errno)); | ||
591 | |||
592 | snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir, | ||
593 | SSH_PRNG_SEED_FILE); | ||
594 | |||
595 | strlcpy(tmpseed, filename, sizeof(tmpseed)); | ||
596 | if (strlcat(tmpseed, ".XXXXXXXXXX", sizeof(tmpseed)) >= | ||
597 | sizeof(tmpseed)) | ||
598 | fatal("PRNG seed filename too long"); | ||
599 | |||
600 | if (RAND_bytes(seed, sizeof(seed)) <= 0) | ||
601 | fatal("PRNG seed extraction failed"); | ||
602 | |||
603 | /* Don't care if the seed doesn't exist */ | ||
604 | prng_check_seedfile(filename); | ||
605 | |||
606 | old_umask = umask(0177); | ||
607 | |||
608 | if ((fd = mkstemp(tmpseed)) == -1) { | ||
609 | debug("WARNING: couldn't make temporary PRNG seedfile %.100s " | ||
610 | "(%.100s)", tmpseed, strerror(errno)); | ||
611 | } else { | ||
612 | debug("writing PRNG seed to file %.100s", tmpseed); | ||
613 | if (atomicio(vwrite, fd, &seed, sizeof(seed)) < sizeof(seed)) { | ||
614 | save_errno = errno; | ||
615 | close(fd); | ||
616 | unlink(tmpseed); | ||
617 | fatal("problem writing PRNG seedfile %.100s " | ||
618 | "(%.100s)", filename, strerror(save_errno)); | ||
619 | } | ||
620 | close(fd); | ||
621 | debug("moving temporary PRNG seed to file %.100s", filename); | ||
622 | if (rename(tmpseed, filename) == -1) { | ||
623 | save_errno = errno; | ||
624 | unlink(tmpseed); | ||
625 | fatal("problem renaming PRNG seedfile from %.100s " | ||
626 | "to %.100s (%.100s)", tmpseed, filename, | ||
627 | strerror(save_errno)); | ||
628 | } | ||
629 | } | ||
630 | umask(old_umask); | ||
631 | } | ||
632 | |||
633 | void | ||
634 | prng_read_seedfile(void) | ||
635 | { | ||
636 | int fd; | ||
637 | char seed[SEED_FILE_SIZE], filename[MAXPATHLEN]; | ||
638 | struct passwd *pw; | ||
639 | |||
640 | pw = getpwuid(getuid()); | ||
641 | if (pw == NULL) | ||
642 | fatal("Couldn't get password entry for current user " | ||
643 | "(%li): %s", (long int)getuid(), strerror(errno)); | ||
644 | |||
645 | snprintf(filename, sizeof(filename), "%.512s/%s", pw->pw_dir, | ||
646 | SSH_PRNG_SEED_FILE); | ||
647 | |||
648 | debug("loading PRNG seed from file %.100s", filename); | ||
649 | |||
650 | if (!prng_check_seedfile(filename)) { | ||
651 | verbose("Random seed file not found or invalid, ignoring."); | ||
652 | return; | ||
653 | } | ||
654 | |||
655 | /* open the file and read in the seed */ | ||
656 | fd = open(filename, O_RDONLY); | ||
657 | if (fd == -1) | ||
658 | fatal("could not open PRNG seedfile %.100s (%.100s)", | ||
659 | filename, strerror(errno)); | ||
660 | |||
661 | if (atomicio(read, fd, &seed, sizeof(seed)) < sizeof(seed)) { | ||
662 | verbose("invalid or short read from PRNG seedfile " | ||
663 | "%.100s - ignoring", filename); | ||
664 | memset(seed, '\0', sizeof(seed)); | ||
665 | } | ||
666 | close(fd); | ||
667 | |||
668 | /* stir in the seed, with estimated entropy zero */ | ||
669 | RAND_add(&seed, sizeof(seed), 0.0); | ||
670 | } | ||
671 | |||
672 | |||
673 | /* | ||
674 | * entropy command initialisation functions | ||
675 | */ | ||
676 | int | ||
677 | prng_read_commands(char *cmdfilename) | ||
678 | { | ||
679 | char cmd[SEED_FILE_SIZE], *cp, line[1024], path[SEED_FILE_SIZE]; | ||
680 | double est; | ||
681 | entropy_cmd_t *entcmd; | ||
682 | FILE *f; | ||
683 | int cur_cmd, linenum, num_cmds, arg; | ||
684 | |||
685 | if ((f = fopen(cmdfilename, "r")) == NULL) { | ||
686 | fatal("couldn't read entropy commands file %.100s: %.100s", | ||
687 | cmdfilename, strerror(errno)); | ||
688 | } | ||
689 | |||
690 | num_cmds = 64; | ||
691 | entcmd = xcalloc(num_cmds, sizeof(entropy_cmd_t)); | ||
692 | |||
693 | /* Read in file */ | ||
694 | cur_cmd = linenum = 0; | ||
695 | while (fgets(line, sizeof(line), f)) { | ||
696 | linenum++; | ||
697 | |||
698 | /* Skip leading whitespace, blank lines and comments */ | ||
699 | cp = line + strspn(line, WHITESPACE); | ||
700 | if ((*cp == 0) || (*cp == '#')) | ||
701 | continue; /* done with this line */ | ||
702 | |||
703 | /* | ||
704 | * The first non-whitespace char should be a double quote | ||
705 | * delimiting the commandline | ||
706 | */ | ||
707 | if (*cp != '"') { | ||
708 | error("bad entropy command, %.100s line %d", | ||
709 | cmdfilename, linenum); | ||
710 | continue; | ||
711 | } | ||
712 | |||
713 | /* | ||
714 | * First token, command args (incl. argv[0]) in double | ||
715 | * quotes | ||
716 | */ | ||
717 | cp = strtok(cp, "\""); | ||
718 | if (cp == NULL) { | ||
719 | error("missing or bad command string, %.100s " | ||
720 | "line %d -- ignored", cmdfilename, linenum); | ||
721 | continue; | ||
722 | } | ||
723 | strlcpy(cmd, cp, sizeof(cmd)); | ||
724 | |||
725 | /* Second token, full command path */ | ||
726 | if ((cp = strtok(NULL, WHITESPACE)) == NULL) { | ||
727 | error("missing command path, %.100s " | ||
728 | "line %d -- ignored", cmdfilename, linenum); | ||
729 | continue; | ||
730 | } | ||
731 | |||
732 | /* Did configure mark this as dead? */ | ||
733 | if (strncmp("undef", cp, 5) == 0) | ||
734 | continue; | ||
735 | |||
736 | strlcpy(path, cp, sizeof(path)); | ||
737 | |||
738 | /* Third token, entropy rate estimate for this command */ | ||
739 | if ((cp = strtok(NULL, WHITESPACE)) == NULL) { | ||
740 | error("missing entropy estimate, %.100s " | ||
741 | "line %d -- ignored", cmdfilename, linenum); | ||
742 | continue; | ||
743 | } | ||
744 | est = strtod(cp, NULL); | ||
745 | |||
746 | /* end of line */ | ||
747 | if ((cp = strtok(NULL, WHITESPACE)) != NULL) { | ||
748 | error("garbage at end of line %d in %.100s " | ||
749 | "-- ignored", linenum, cmdfilename); | ||
750 | continue; | ||
751 | } | ||
752 | |||
753 | /* save the command for debug messages */ | ||
754 | entcmd[cur_cmd].cmdstring = xstrdup(cmd); | ||
755 | |||
756 | /* split the command args */ | ||
757 | cp = strtok(cmd, WHITESPACE); | ||
758 | arg = 0; | ||
759 | do { | ||
760 | entcmd[cur_cmd].args[arg] = xstrdup(cp); | ||
761 | arg++; | ||
762 | } while(arg < NUM_ARGS && (cp = strtok(NULL, WHITESPACE))); | ||
763 | |||
764 | if (strtok(NULL, WHITESPACE)) | ||
765 | error("ignored extra commands (max %d), %.100s " | ||
766 | "line %d", NUM_ARGS, cmdfilename, linenum); | ||
767 | |||
768 | /* Copy the command path and rate estimate */ | ||
769 | entcmd[cur_cmd].path = xstrdup(path); | ||
770 | entcmd[cur_cmd].rate = est; | ||
771 | |||
772 | /* Initialise other values */ | ||
773 | entcmd[cur_cmd].sticky_badness = 1; | ||
774 | |||
775 | cur_cmd++; | ||
776 | |||
777 | /* | ||
778 | * If we've filled the array, reallocate it twice the size | ||
779 | * Do this now because even if this we're on the last | ||
780 | * command we need another slot to mark the last entry | ||
781 | */ | ||
782 | if (cur_cmd == num_cmds) { | ||
783 | num_cmds *= 2; | ||
784 | entcmd = xrealloc(entcmd, num_cmds, | ||
785 | sizeof(entropy_cmd_t)); | ||
786 | } | ||
787 | } | ||
788 | |||
789 | /* zero the last entry */ | ||
790 | memset(&entcmd[cur_cmd], '\0', sizeof(entropy_cmd_t)); | ||
791 | |||
792 | /* trim to size */ | ||
793 | entropy_cmds = xrealloc(entcmd, (cur_cmd + 1), | ||
794 | sizeof(entropy_cmd_t)); | ||
795 | |||
796 | debug("Loaded %d entropy commands from %.100s", cur_cmd, | ||
797 | cmdfilename); | ||
798 | |||
799 | fclose(f); | ||
800 | return cur_cmd < MIN_ENTROPY_SOURCES ? -1 : 0; | ||
801 | } | ||
802 | |||
803 | void | ||
804 | usage(void) | ||
805 | { | ||
806 | fprintf(stderr, "Usage: %s [options]\n", __progname); | ||
807 | fprintf(stderr, " -v Verbose; display verbose debugging messages.\n"); | ||
808 | fprintf(stderr, " Multiple -v increases verbosity.\n"); | ||
809 | fprintf(stderr, " -x Force output in hexadecimal (for debugging)\n"); | ||
810 | fprintf(stderr, " -X Force output in binary\n"); | ||
811 | fprintf(stderr, " -b bytes Number of bytes to output (default %d)\n", | ||
812 | OUTPUT_SEED_SIZE); | ||
813 | } | ||
814 | |||
815 | int | ||
816 | main(int argc, char **argv) | ||
817 | { | ||
818 | unsigned char *buf; | ||
819 | int ret, ch, debug_level, output_hex, bytes; | ||
820 | extern char *optarg; | ||
821 | extern int optind; | ||
822 | LogLevel ll; | ||
823 | |||
824 | __progname = ssh_get_progname(argv[0]); | ||
825 | log_init(argv[0], SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_USER, 1); | ||
826 | |||
827 | ll = SYSLOG_LEVEL_INFO; | ||
828 | debug_level = output_hex = 0; | ||
829 | bytes = OUTPUT_SEED_SIZE; | ||
830 | |||
831 | /* Don't write binary data to a tty, unless we are forced to */ | ||
832 | if (isatty(STDOUT_FILENO)) | ||
833 | output_hex = 1; | ||
834 | |||
835 | while ((ch = getopt(argc, argv, "vxXhb:")) != -1) { | ||
836 | switch (ch) { | ||
837 | case 'v': | ||
838 | if (debug_level < 3) | ||
839 | ll = SYSLOG_LEVEL_DEBUG1 + debug_level++; | ||
840 | break; | ||
841 | case 'x': | ||
842 | output_hex = 1; | ||
843 | break; | ||
844 | case 'X': | ||
845 | output_hex = 0; | ||
846 | break; | ||
847 | case 'b': | ||
848 | if ((bytes = atoi(optarg)) <= 0) | ||
849 | fatal("Invalid number of output bytes"); | ||
850 | break; | ||
851 | case 'h': | ||
852 | usage(); | ||
853 | exit(0); | ||
854 | default: | ||
855 | error("Invalid commandline option"); | ||
856 | usage(); | ||
857 | exit(1); | ||
858 | } | ||
859 | } | ||
860 | log_init(argv[0], ll, SYSLOG_FACILITY_USER, 1); | ||
861 | |||
862 | if (argc != optind) { | ||
863 | error("Unexpected commandline arguments."); | ||
864 | usage(); | ||
865 | exit(1); | ||
866 | } | ||
867 | |||
868 | #ifdef USE_SEED_FILES | ||
869 | prng_read_seedfile(); | ||
870 | #endif | ||
871 | |||
872 | buf = xmalloc(bytes); | ||
873 | |||
874 | /* | ||
875 | * Seed the RNG from wherever we can | ||
876 | */ | ||
877 | |||
878 | /* Take whatever is on the stack, but don't credit it */ | ||
879 | RAND_add(buf, bytes, 0); | ||
880 | |||
881 | debug("Seeded RNG with %i bytes from system calls", | ||
882 | (int)stir_from_system()); | ||
883 | |||
884 | /* try prngd, fall back to commands if prngd fails or not configured */ | ||
885 | if (seed_from_prngd(buf, bytes) == 0) { | ||
886 | RAND_add(buf, bytes, bytes); | ||
887 | } else { | ||
888 | /* Read in collection commands */ | ||
889 | if (prng_read_commands(SSH_PRNG_COMMAND_FILE) == -1) | ||
890 | fatal("PRNG initialisation failed -- exiting."); | ||
891 | debug("Seeded RNG with %i bytes from programs", | ||
892 | (int)stir_from_programs()); | ||
893 | } | ||
894 | |||
895 | #ifdef USE_SEED_FILES | ||
896 | prng_write_seedfile(); | ||
897 | #endif | ||
898 | |||
899 | /* | ||
900 | * Write the seed to stdout | ||
901 | */ | ||
902 | |||
903 | if (!RAND_status()) | ||
904 | fatal("Not enough entropy in RNG"); | ||
905 | |||
906 | if (RAND_bytes(buf, bytes) <= 0) | ||
907 | fatal("Couldn't extract entropy from PRNG"); | ||
908 | |||
909 | if (output_hex) { | ||
910 | for(ret = 0; ret < bytes; ret++) | ||
911 | printf("%02x", (unsigned char)(buf[ret])); | ||
912 | printf("\n"); | ||
913 | } else | ||
914 | ret = atomicio(vwrite, STDOUT_FILENO, buf, bytes); | ||
915 | |||
916 | memset(buf, '\0', bytes); | ||
917 | xfree(buf); | ||
918 | |||
919 | return ret == bytes ? 0 : 1; | ||
920 | } | ||
921 | |||
922 | /* | ||
923 | * We may attempt to re-seed during mkstemp if we are using the one in the | ||
924 | * compat library (via mkstemp -> _gettemp -> arc4random -> seed_rng) so we | ||
925 | * need our own seed_rng(). We must also check that we have enough entropy. | ||
926 | */ | ||
927 | void | ||
928 | seed_rng(void) | ||
929 | { | ||
930 | if (!RAND_status()) | ||
931 | fatal("Not enough entropy in RNG"); | ||
932 | } | ||