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Diffstat (limited to 'entropy.c')
-rw-r--r-- | entropy.c | 436 |
1 files changed, 436 insertions, 0 deletions
diff --git a/entropy.c b/entropy.c new file mode 100644 index 000000000..16731775c --- /dev/null +++ b/entropy.c | |||
@@ -0,0 +1,436 @@ | |||
1 | /* | ||
2 | * Copyright (c) 2000 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 | * 3. All advertising materials mentioning features or use of this software | ||
13 | * must display the following acknowledgement: | ||
14 | * This product includes software developed by Markus Friedl. | ||
15 | * 4. The name of the author may not be used to endorse or promote products | ||
16 | * derived from this software without specific prior written permission. | ||
17 | * | ||
18 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR | ||
19 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES | ||
20 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. | ||
21 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, | ||
22 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | ||
23 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | ||
24 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | ||
25 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | ||
26 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF | ||
27 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | ||
28 | */ | ||
29 | |||
30 | #include "includes.h" | ||
31 | |||
32 | #include "ssh.h" | ||
33 | #include "xmalloc.h" | ||
34 | |||
35 | #ifdef HAVE_OPENSSL | ||
36 | # include <openssl/rand.h> | ||
37 | # include <openssl/sha.h> | ||
38 | #endif | ||
39 | #ifdef HAVE_SSL | ||
40 | # include <ssl/rand.h> | ||
41 | # include <ssl/sha.h> | ||
42 | #endif | ||
43 | |||
44 | RCSID("$Id: entropy.c,v 1.1 2000/04/03 04:50:45 damien Exp $"); | ||
45 | |||
46 | #ifdef EGD_SOCKET | ||
47 | #ifndef offsetof | ||
48 | # define offsetof(type, member) ((size_t) &((type *)0)->member) | ||
49 | #endif | ||
50 | /* Collect entropy from EGD */ | ||
51 | void get_random_bytes(unsigned char *buf, int len) | ||
52 | { | ||
53 | static int egd_socket = -1; | ||
54 | int c; | ||
55 | char egd_message[2] = { 0x02, 0x00 }; | ||
56 | struct sockaddr_un addr; | ||
57 | int addr_len; | ||
58 | |||
59 | memset(&addr, '\0', sizeof(addr)); | ||
60 | addr.sun_family = AF_UNIX; | ||
61 | |||
62 | /* FIXME: compile time check? */ | ||
63 | if (sizeof(EGD_SOCKET) > sizeof(addr.sun_path)) | ||
64 | fatal("Random pool path is too long"); | ||
65 | |||
66 | strcpy(addr.sun_path, EGD_SOCKET); | ||
67 | |||
68 | addr_len = offsetof(struct sockaddr_un, sun_path) + sizeof(EGD_SOCKET); | ||
69 | |||
70 | if (egd_socket == -1) { | ||
71 | egd_socket = socket(AF_UNIX, SOCK_STREAM, 0); | ||
72 | if (egd_socket == -1) | ||
73 | fatal("Couldn't create AF_UNIX socket: %s", strerror(errno)); | ||
74 | if (connect(egd_socket, (struct sockaddr*)&addr, addr_len) == -1) | ||
75 | fatal("Couldn't connect to EGD socket \"%s\": %s", addr.sun_path, strerror(errno)); | ||
76 | } | ||
77 | |||
78 | if (len > 255) | ||
79 | fatal("Too many bytes to read from EGD"); | ||
80 | |||
81 | /* Send blocking read request to EGD */ | ||
82 | egd_message[1] = len; | ||
83 | |||
84 | c = atomicio(write, egd_socket, egd_message, sizeof(egd_message)); | ||
85 | if (c == -1) | ||
86 | fatal("Couldn't write to EGD socket \"%s\": %s", EGD_SOCKET, strerror(errno)); | ||
87 | |||
88 | c = atomicio(read, egd_socket, buf, len); | ||
89 | if (c <= 0) | ||
90 | fatal("Couldn't read from EGD socket \"%s\": %s", EGD_SOCKET, strerror(errno)); | ||
91 | |||
92 | close(EGD_SOCKET); | ||
93 | } | ||
94 | #else /* !EGD_SOCKET */ | ||
95 | #ifdef RANDOM_POOL | ||
96 | /* Collect entropy from /dev/urandom or pipe */ | ||
97 | void get_random_bytes(unsigned char *buf, int len) | ||
98 | { | ||
99 | static int random_pool = -1; | ||
100 | int c; | ||
101 | |||
102 | if (random_pool == -1) { | ||
103 | random_pool = open(RANDOM_POOL, O_RDONLY); | ||
104 | if (random_pool == -1) | ||
105 | fatal("Couldn't open random pool \"%s\": %s", RANDOM_POOL, strerror(errno)); | ||
106 | } | ||
107 | |||
108 | verbose("randfd: %i", random_pool); | ||
109 | |||
110 | c = atomicio(read, random_pool, buf, len); | ||
111 | if (c <= 0) | ||
112 | fatal("Couldn't read from random pool \"%s\": %s", RANDOM_POOL, strerror(errno)); | ||
113 | } | ||
114 | #endif /* RANDOM_POOL */ | ||
115 | #endif /* EGD_SOCKET */ | ||
116 | |||
117 | #if !defined(EGD_SOCKET) && !defined(RANDOM_POOL) | ||
118 | /* | ||
119 | * FIXME: proper entropy estimations. All current values are guesses | ||
120 | * FIXME: Need timeout for slow moving programs | ||
121 | * FIXME: More entropy sources | ||
122 | */ | ||
123 | |||
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); | ||
129 | double hash_output_from_command(const char *path, const char **args, char *hash); | ||
130 | |||
131 | typedef struct | ||
132 | { | ||
133 | /* Proportion of data that is entropy */ | ||
134 | double rate; | ||
135 | /* Path to executable */ | ||
136 | const char *path; | ||
137 | /* argv to pass to executable */ | ||
138 | const char *args[5]; | ||
139 | } entropy_source_t; | ||
140 | |||
141 | entropy_source_t entropy_sources[] = { | ||
142 | #ifdef PROG_LS | ||
143 | { 0.002, PROG_LS, { "ls", "-alni", "/var/log", NULL } }, | ||
144 | { 0.002, PROG_LS, { "ls", "-alni", "/var/adm", NULL } }, | ||
145 | { 0.002, PROG_LS, { "ls", "-alni", "/var/mail", NULL } }, | ||
146 | { 0.002, PROG_LS, { "ls", "-alni", "/var/spool/mail", NULL } }, | ||
147 | { 0.002, PROG_LS, { "ls", "-alni", "/proc", NULL } }, | ||
148 | { 0.002, PROG_LS, { "ls", "-alni", "/tmp", NULL } }, | ||
149 | #endif | ||
150 | #ifdef PROG_NETSTAT | ||
151 | { 0.005, PROG_NETSTAT, { "netstat","-an", NULL, NULL } }, | ||
152 | { 0.010, PROG_NETSTAT, { "netstat","-in", NULL, NULL } }, | ||
153 | { 0.002, PROG_NETSTAT, { "netstat","-rn", NULL, NULL } }, | ||
154 | { 0.002, PROG_NETSTAT, { "netstat","-s", NULL, NULL } }, | ||
155 | #endif | ||
156 | #ifdef PROG_ARP | ||
157 | { 0.002, PROG_ARP, { "arp","-a","-n", NULL } }, | ||
158 | #endif | ||
159 | #ifdef PROG_IFCONFIG | ||
160 | { 0.002, PROG_IFCONFIG, { "ifconfig", "-a", NULL, NULL } }, | ||
161 | #endif | ||
162 | #ifdef PROG_PS | ||
163 | { 0.003, PROG_PS, { "ps", "laxww", NULL, NULL } }, | ||
164 | { 0.003, PROG_PS, { "ps", "-al", NULL, NULL } }, | ||
165 | { 0.003, PROG_PS, { "ps", "-efl", NULL, NULL } }, | ||
166 | #endif | ||
167 | #ifdef PROG_W | ||
168 | { 0.005, PROG_W, { "w", NULL, NULL, NULL } }, | ||
169 | #endif | ||
170 | #ifdef PROG_WHO | ||
171 | { 0.001, PROG_WHO, { "who","-i", NULL, NULL } }, | ||
172 | #endif | ||
173 | #ifdef PROG_LAST | ||
174 | { 0.001, PROG_LAST, { "last", NULL, NULL, NULL } }, | ||
175 | #endif | ||
176 | #ifdef PROG_LASTLOG | ||
177 | { 0.001, PROG_LASTLOG, { "lastlog", NULL, NULL, NULL } }, | ||
178 | #endif | ||
179 | #ifdef PROG_DF | ||
180 | { 0.010, PROG_DF, { "df", NULL, NULL, NULL } }, | ||
181 | { 0.010, PROG_DF, { "df", "-i", NULL, NULL } }, | ||
182 | #endif | ||
183 | #ifdef PROG_VMSTAT | ||
184 | { 0.010, PROG_VMSTAT, { "vmstat", NULL, NULL, NULL } }, | ||
185 | #endif | ||
186 | #ifdef PROG_UPTIME | ||
187 | { 0.001, PROG_UPTIME, { "uptime", NULL, NULL, NULL } }, | ||
188 | #endif | ||
189 | #ifdef PROG_IPCS | ||
190 | { 0.001, PROG_IPCS, { "-a", NULL, NULL, NULL } }, | ||
191 | #endif | ||
192 | #ifdef PROG_TAIL | ||
193 | { 0.001, PROG_TAIL, { "tail", "-200", "/var/log/messages", NULL, NULL } }, | ||
194 | { 0.001, PROG_TAIL, { "tail", "-200", "/var/log/syslog", NULL, NULL } }, | ||
195 | { 0.001, PROG_TAIL, { "tail", "-200", "/var/adm/messages", NULL, NULL } }, | ||
196 | { 0.001, PROG_TAIL, { "tail", "-200", "/var/adm/syslog", NULL, NULL } }, | ||
197 | { 0.001, PROG_TAIL, { "tail", "-200", "/var/log/maillog", NULL, NULL } }, | ||
198 | { 0.001, PROG_TAIL, { "tail", "-200", "/var/adm/maillog", NULL, NULL } }, | ||
199 | #endif | ||
200 | { 0.000, NULL, { NULL, NULL, NULL, NULL, NULL } }, | ||
201 | }; | ||
202 | |||
203 | |||
204 | double | ||
205 | stir_from_system(void) | ||
206 | { | ||
207 | double total_entropy_estimate; | ||
208 | long int i; | ||
209 | |||
210 | total_entropy_estimate = 0; | ||
211 | |||
212 | i = getpid(); | ||
213 | RAND_add(&i, sizeof(i), 0.1); | ||
214 | total_entropy_estimate += 0.1; | ||
215 | |||
216 | i = getppid(); | ||
217 | RAND_add(&i, sizeof(i), 0.1); | ||
218 | total_entropy_estimate += 0.1; | ||
219 | |||
220 | i = getuid(); | ||
221 | RAND_add(&i, sizeof(i), 0.0); | ||
222 | i = getgid(); | ||
223 | RAND_add(&i, sizeof(i), 0.0); | ||
224 | |||
225 | total_entropy_estimate += stir_gettimeofday(1.0); | ||
226 | total_entropy_estimate += stir_clock(0.2); | ||
227 | total_entropy_estimate += stir_rusage(RUSAGE_SELF, 2.0); | ||
228 | |||
229 | return(total_entropy_estimate); | ||
230 | } | ||
231 | |||
232 | double | ||
233 | stir_from_programs(void) | ||
234 | { | ||
235 | int i; | ||
236 | int c; | ||
237 | double entropy_estimate; | ||
238 | double total_entropy_estimate; | ||
239 | char hash[SHA_DIGEST_LENGTH]; | ||
240 | |||
241 | /* | ||
242 | * Run through list of programs twice to catch differences | ||
243 | */ | ||
244 | total_entropy_estimate = 0; | ||
245 | for(i = 0; i < 2; i++) { | ||
246 | c = 0; | ||
247 | while (entropy_sources[c].path != NULL) { | ||
248 | /* Hash output from command */ | ||
249 | entropy_estimate = hash_output_from_command(entropy_sources[c].path, | ||
250 | entropy_sources[c].args, hash); | ||
251 | |||
252 | /* Scale back entropy estimate according to command's rate */ | ||
253 | entropy_estimate *= entropy_sources[c].rate; | ||
254 | |||
255 | /* Upper bound of entropy estimate is SHA_DIGEST_LENGTH */ | ||
256 | if (entropy_estimate > SHA_DIGEST_LENGTH) | ||
257 | entropy_estimate = SHA_DIGEST_LENGTH; | ||
258 | |||
259 | /* * Scale back estimates for subsequent passes through list */ | ||
260 | entropy_estimate /= 10.0 * (i + 1.0); | ||
261 | |||
262 | /* Stir it in */ | ||
263 | RAND_add(hash, sizeof(hash), entropy_estimate); | ||
264 | |||
265 | /* FIXME: turn this off later */ | ||
266 | #if 1 | ||
267 | debug("Got %0.2f bytes of entropy from %s", entropy_estimate, | ||
268 | entropy_sources[c].path); | ||
269 | #endif | ||
270 | |||
271 | total_entropy_estimate += entropy_estimate; | ||
272 | |||
273 | /* Execution times should be a little unpredictable */ | ||
274 | total_entropy_estimate += stir_gettimeofday(0.05); | ||
275 | total_entropy_estimate += stir_clock(0.05); | ||
276 | total_entropy_estimate += stir_rusage(RUSAGE_SELF, 0.1); | ||
277 | total_entropy_estimate += stir_rusage(RUSAGE_CHILDREN, 0.1); | ||
278 | |||
279 | c++; | ||
280 | } | ||
281 | } | ||
282 | |||
283 | return(total_entropy_estimate); | ||
284 | } | ||
285 | |||
286 | double | ||
287 | stir_gettimeofday(double entropy_estimate) | ||
288 | { | ||
289 | struct timeval tv; | ||
290 | |||
291 | if (gettimeofday(&tv, NULL) == -1) | ||
292 | fatal("Couldn't gettimeofday: %s", strerror(errno)); | ||
293 | |||
294 | RAND_add(&tv, sizeof(tv), entropy_estimate); | ||
295 | |||
296 | return(entropy_estimate); | ||
297 | } | ||
298 | |||
299 | double | ||
300 | stir_clock(double entropy_estimate) | ||
301 | { | ||
302 | #ifdef HAVE_CLOCK | ||
303 | clock_t c; | ||
304 | |||
305 | c = clock(); | ||
306 | RAND_add(&c, sizeof(c), entropy_estimate); | ||
307 | |||
308 | return(entropy_estimate); | ||
309 | #else /* _HAVE_CLOCK */ | ||
310 | return(0); | ||
311 | #endif /* _HAVE_CLOCK */ | ||
312 | } | ||
313 | |||
314 | double | ||
315 | stir_rusage(int who, double entropy_estimate) | ||
316 | { | ||
317 | #ifdef HAVE_GETRUSAGE | ||
318 | struct rusage ru; | ||
319 | |||
320 | if (getrusage(who, &ru) == -1) | ||
321 | fatal("Couldn't getrusage: %s", strerror(errno)); | ||
322 | |||
323 | RAND_add(&ru, sizeof(ru), 0.1); | ||
324 | |||
325 | return(entropy_estimate); | ||
326 | #else /* _HAVE_GETRUSAGE */ | ||
327 | return(0); | ||
328 | #endif /* _HAVE_GETRUSAGE */ | ||
329 | } | ||
330 | |||
331 | double | ||
332 | hash_output_from_command(const char *path, const char **args, char *hash) | ||
333 | { | ||
334 | static int devnull = -1; | ||
335 | int p[2]; | ||
336 | pid_t pid; | ||
337 | int status; | ||
338 | char buf[2048]; | ||
339 | int bytes_read; | ||
340 | int total_bytes_read; | ||
341 | SHA_CTX sha; | ||
342 | |||
343 | if (devnull == -1) { | ||
344 | devnull = open("/dev/null", O_RDWR); | ||
345 | if (devnull == -1) | ||
346 | fatal("Couldn't open /dev/null: %s", strerror(errno)); | ||
347 | } | ||
348 | |||
349 | if (pipe(p) == -1) | ||
350 | fatal("Couldn't open pipe: %s", strerror(errno)); | ||
351 | |||
352 | switch (pid = fork()) { | ||
353 | case -1: /* Error */ | ||
354 | close(p[0]); | ||
355 | close(p[1]); | ||
356 | fatal("Couldn't fork: %s", strerror(errno)); | ||
357 | /* NOTREACHED */ | ||
358 | case 0: /* Child */ | ||
359 | close(0); | ||
360 | close(1); | ||
361 | close(2); | ||
362 | dup2(devnull, 0); | ||
363 | dup2(p[1], 1); | ||
364 | dup2(p[1], 2); | ||
365 | close(p[0]); | ||
366 | close(p[1]); | ||
367 | close(devnull); | ||
368 | |||
369 | execv(path, (char**)args); | ||
370 | debug("(child) Couldn't exec '%s': %s", path, strerror(errno)); | ||
371 | _exit(-1); | ||
372 | default: /* Parent */ | ||
373 | break; | ||
374 | } | ||
375 | |||
376 | RAND_add(&pid, sizeof(&pid), 0.0); | ||
377 | |||
378 | close(p[1]); | ||
379 | |||
380 | /* Hash output from child */ | ||
381 | SHA1_Init(&sha); | ||
382 | total_bytes_read = 0; | ||
383 | while ((bytes_read = read(p[0], buf, sizeof(buf))) > 0) { | ||
384 | SHA1_Update(&sha, buf, bytes_read); | ||
385 | total_bytes_read += bytes_read; | ||
386 | RAND_add(&bytes_read, sizeof(&bytes_read), 0.0); | ||
387 | } | ||
388 | SHA1_Final(hash, &sha); | ||
389 | |||
390 | close(p[0]); | ||
391 | |||
392 | if (waitpid(pid, &status, 0) == -1) { | ||
393 | error("Couldn't wait for child '%s' completion: %s", path, | ||
394 | strerror(errno)); | ||
395 | return(-1); | ||
396 | } | ||
397 | |||
398 | RAND_add(&status, sizeof(&status), 0.0); | ||
399 | |||
400 | if (!WIFEXITED(status) || (WEXITSTATUS(status) != 0)) | ||
401 | return(0.0); | ||
402 | else | ||
403 | return(total_bytes_read); | ||
404 | } | ||
405 | #endif /* defined(EGD_SOCKET) || defined(RANDOM_POOL) */ | ||
406 | |||
407 | #if defined(EGD_SOCKET) || defined(RANDOM_POOL) | ||
408 | /* | ||
409 | * Seed OpenSSL's random number pool from Kernel random number generator | ||
410 | * or EGD | ||
411 | */ | ||
412 | void | ||
413 | seed_rng(void) | ||
414 | { | ||
415 | char buf[32]; | ||
416 | |||
417 | debug("Seeding random number generator"); | ||
418 | get_random_bytes(buf, sizeof(buf)); | ||
419 | RAND_add(buf, sizeof(buf), sizeof(buf)); | ||
420 | memset(buf, '\0', sizeof(buf)); | ||
421 | } | ||
422 | #else /* defined(EGD_SOCKET) || defined(RANDOM_POOL) */ | ||
423 | /* | ||
424 | * Conditionally Seed OpenSSL's random number pool syscalls and program output | ||
425 | */ | ||
426 | void | ||
427 | seed_rng(void) | ||
428 | { | ||
429 | if (!RAND_status()) { | ||
430 | debug("Seeding random number generator."); | ||
431 | debug("%i bytes from system calls", (int)stir_from_system()); | ||
432 | debug("%i bytes from programs", (int)stir_from_programs()); | ||
433 | debug("OpenSSL random status is now %i\n", RAND_status()); | ||
434 | } | ||
435 | } | ||
436 | #endif /* defined(EGD_SOCKET) || defined(RANDOM_POOL) */ | ||