2 * Copyright (c) 2000 Damien Miller. All rights reserved.
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
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.
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.
35 #include <openssl/rand.h>
36 #include <openssl/sha.h>
42 # define offsetof(type, member) ((size_t) &((type *)0)->member)
44 /* Collect entropy from EGD */
45 void get_random_bytes(unsigned char *buf, int len)
47 static int egd_socket = -1;
49 char egd_message[2] = { 0x02, 0x00 };
50 struct sockaddr_un addr;
53 memset(&addr, '\0', sizeof(addr));
54 addr.sun_family = AF_UNIX;
56 /* FIXME: compile time check? */
57 if (sizeof(EGD_SOCKET) > sizeof(addr.sun_path))
58 fatal("Random pool path is too long");
60 strcpy(addr.sun_path, EGD_SOCKET);
62 addr_len = offsetof(struct sockaddr_un, sun_path) + sizeof(EGD_SOCKET);
64 if (egd_socket == -1) {
65 egd_socket = socket(AF_UNIX, SOCK_STREAM, 0);
67 fatal("Couldn't create AF_UNIX socket: %s", strerror(errno));
68 if (connect(egd_socket, (struct sockaddr*)&addr, addr_len) == -1)
69 fatal("Couldn't connect to EGD socket \"%s\": %s", addr.sun_path, strerror(errno));
73 fatal("Too many bytes to read from EGD");
75 /* Send blocking read request to EGD */
78 c = atomicio(write, egd_socket, egd_message, sizeof(egd_message));
80 fatal("Couldn't write to EGD socket \"%s\": %s", EGD_SOCKET, strerror(errno));
82 c = atomicio(read, egd_socket, buf, len);
84 fatal("Couldn't read from EGD socket \"%s\": %s", EGD_SOCKET, strerror(errno));
88 #else /* !EGD_SOCKET */
90 /* Collect entropy from /dev/urandom or pipe */
91 void get_random_bytes(unsigned char *buf, int len)
93 static int random_pool = -1;
96 if (random_pool == -1) {
97 random_pool = open(RANDOM_POOL, O_RDONLY);
98 if (random_pool == -1)
99 fatal("Couldn't open random pool \"%s\": %s", RANDOM_POOL, strerror(errno));
102 c = atomicio(read, random_pool, buf, len);
104 fatal("Couldn't read from random pool \"%s\": %s", RANDOM_POOL, strerror(errno));
106 #endif /* RANDOM_POOL */
107 #endif /* EGD_SOCKET */
109 #if !defined(EGD_SOCKET) && !defined(RANDOM_POOL)
111 * FIXME: proper entropy estimations. All current values are guesses
112 * FIXME: Need timeout for slow moving programs
113 * FIXME: More entropy sources
116 double stir_from_system(void);
117 double stir_from_programs(void);
118 double stir_gettimeofday(double entropy_estimate);
119 double stir_clock(double entropy_estimate);
120 double stir_rusage(int who, double entropy_estimate);
121 double hash_output_from_command(const char *path, const char **args, char *hash);
125 /* Proportion of data that is entropy */
127 /* Path to executable */
129 /* argv to pass to executable */
133 entropy_source_t entropy_sources[] = {
135 { 0.002, PROG_LS, { "ls", "-alni", "/var/log", NULL } },
136 { 0.002, PROG_LS, { "ls", "-alni", "/var/adm", NULL } },
137 { 0.002, PROG_LS, { "ls", "-alni", "/var/mail", NULL } },
138 { 0.002, PROG_LS, { "ls", "-alni", "/var/spool/mail", NULL } },
139 { 0.002, PROG_LS, { "ls", "-alni", "/proc", NULL } },
140 { 0.002, PROG_LS, { "ls", "-alni", "/tmp", NULL } },
143 { 0.005, PROG_NETSTAT, { "netstat","-an", NULL, NULL } },
144 { 0.010, PROG_NETSTAT, { "netstat","-in", NULL, NULL } },
145 { 0.002, PROG_NETSTAT, { "netstat","-rn", NULL, NULL } },
146 { 0.002, PROG_NETSTAT, { "netstat","-s", NULL, NULL } },
149 { 0.002, PROG_ARP, { "arp","-a","-n", NULL } },
152 { 0.002, PROG_IFCONFIG, { "ifconfig", "-a", NULL, NULL } },
155 { 0.003, PROG_PS, { "ps", "laxww", NULL, NULL } },
156 { 0.003, PROG_PS, { "ps", "-al", NULL, NULL } },
157 { 0.003, PROG_PS, { "ps", "-efl", NULL, NULL } },
160 { 0.005, PROG_W, { "w", NULL, NULL, NULL } },
163 { 0.001, PROG_WHO, { "who","-i", NULL, NULL } },
166 { 0.001, PROG_LAST, { "last", NULL, NULL, NULL } },
169 { 0.001, PROG_LASTLOG, { "lastlog", NULL, NULL, NULL } },
172 { 0.010, PROG_DF, { "df", NULL, NULL, NULL } },
173 { 0.010, PROG_DF, { "df", "-i", NULL, NULL } },
176 { 0.010, PROG_VMSTAT, { "vmstat", NULL, NULL, NULL } },
179 { 0.001, PROG_UPTIME, { "uptime", NULL, NULL, NULL } },
182 { 0.001, PROG_IPCS, { "-a", NULL, NULL, NULL } },
185 { 0.001, PROG_TAIL, { "tail", "-200", "/var/log/messages", NULL, NULL } },
186 { 0.001, PROG_TAIL, { "tail", "-200", "/var/log/syslog", NULL, NULL } },
187 { 0.001, PROG_TAIL, { "tail", "-200", "/var/adm/messages", NULL, NULL } },
188 { 0.001, PROG_TAIL, { "tail", "-200", "/var/adm/syslog", NULL, NULL } },
189 { 0.001, PROG_TAIL, { "tail", "-200", "/var/log/maillog", NULL, NULL } },
190 { 0.001, PROG_TAIL, { "tail", "-200", "/var/adm/maillog", NULL, NULL } },
192 { 0.000, NULL, { NULL, NULL, NULL, NULL, NULL } },
196 stir_from_system(void)
198 double total_entropy_estimate;
201 total_entropy_estimate = 0;
204 RAND_add(&i, sizeof(i), 0.1);
205 total_entropy_estimate += 0.1;
208 RAND_add(&i, sizeof(i), 0.1);
209 total_entropy_estimate += 0.1;
212 RAND_add(&i, sizeof(i), 0.0);
214 RAND_add(&i, sizeof(i), 0.0);
216 total_entropy_estimate += stir_gettimeofday(1.0);
217 total_entropy_estimate += stir_clock(0.2);
218 total_entropy_estimate += stir_rusage(RUSAGE_SELF, 2.0);
220 return(total_entropy_estimate);
224 stir_from_programs(void)
228 double entropy_estimate;
229 double total_entropy_estimate;
230 char hash[SHA_DIGEST_LENGTH];
233 * Run through list of programs twice to catch differences
235 total_entropy_estimate = 0;
236 for(i = 0; i < 2; i++) {
238 while (entropy_sources[c].path != NULL) {
239 /* Hash output from command */
240 entropy_estimate = hash_output_from_command(entropy_sources[c].path,
241 entropy_sources[c].args, hash);
243 /* Scale back entropy estimate according to command's rate */
244 entropy_estimate *= entropy_sources[c].rate;
246 /* Upper bound of entropy estimate is SHA_DIGEST_LENGTH */
247 if (entropy_estimate > SHA_DIGEST_LENGTH)
248 entropy_estimate = SHA_DIGEST_LENGTH;
250 /* * Scale back estimates for subsequent passes through list */
251 entropy_estimate /= 10.0 * (i + 1.0);
254 RAND_add(hash, sizeof(hash), entropy_estimate);
256 /* FIXME: turn this off later */
258 debug("Got %0.2f bytes of entropy from %s", entropy_estimate,
259 entropy_sources[c].path);
262 total_entropy_estimate += entropy_estimate;
264 /* Execution times should be a little unpredictable */
265 total_entropy_estimate += stir_gettimeofday(0.05);
266 total_entropy_estimate += stir_clock(0.05);
267 total_entropy_estimate += stir_rusage(RUSAGE_SELF, 0.1);
268 total_entropy_estimate += stir_rusage(RUSAGE_CHILDREN, 0.1);
274 return(total_entropy_estimate);
278 stir_gettimeofday(double entropy_estimate)
282 if (gettimeofday(&tv, NULL) == -1)
283 fatal("Couldn't gettimeofday: %s", strerror(errno));
285 RAND_add(&tv, sizeof(tv), entropy_estimate);
287 return(entropy_estimate);
291 stir_clock(double entropy_estimate)
297 RAND_add(&c, sizeof(c), entropy_estimate);
299 return(entropy_estimate);
300 #else /* _HAVE_CLOCK */
302 #endif /* _HAVE_CLOCK */
306 stir_rusage(int who, double entropy_estimate)
308 #ifdef HAVE_GETRUSAGE
311 if (getrusage(who, &ru) == -1)
312 fatal("Couldn't getrusage: %s", strerror(errno));
314 RAND_add(&ru, sizeof(ru), 0.1);
316 return(entropy_estimate);
317 #else /* _HAVE_GETRUSAGE */
319 #endif /* _HAVE_GETRUSAGE */
323 hash_output_from_command(const char *path, const char **args, char *hash)
325 static int devnull = -1;
331 int total_bytes_read;
335 devnull = open("/dev/null", O_RDWR);
337 fatal("Couldn't open /dev/null: %s", strerror(errno));
341 fatal("Couldn't open pipe: %s", strerror(errno));
343 switch (pid = fork()) {
347 fatal("Couldn't fork: %s", strerror(errno));
360 execv(path, (char**)args);
361 debug("(child) Couldn't exec '%s': %s", path, strerror(errno));
363 default: /* Parent */
367 RAND_add(&pid, sizeof(&pid), 0.0);
371 /* Hash output from child */
373 total_bytes_read = 0;
374 while ((bytes_read = read(p[0], buf, sizeof(buf))) > 0) {
375 SHA1_Update(&sha, buf, bytes_read);
376 total_bytes_read += bytes_read;
377 RAND_add(&bytes_read, sizeof(&bytes_read), 0.0);
379 SHA1_Final(hash, &sha);
383 if (waitpid(pid, &status, 0) == -1) {
384 error("Couldn't wait for child '%s' completion: %s", path,
389 RAND_add(&status, sizeof(&status), 0.0);
391 if (!WIFEXITED(status) || (WEXITSTATUS(status) != 0))
394 return(total_bytes_read);
396 #endif /* defined(EGD_SOCKET) || defined(RANDOM_POOL) */
398 #if defined(EGD_SOCKET) || defined(RANDOM_POOL)
400 * Seed OpenSSL's random number pool from Kernel random number generator
408 debug("Seeding random number generator");
409 get_random_bytes(buf, sizeof(buf));
410 RAND_add(buf, sizeof(buf), sizeof(buf));
411 memset(buf, '\0', sizeof(buf));
413 #else /* defined(EGD_SOCKET) || defined(RANDOM_POOL) */
415 * Conditionally Seed OpenSSL's random number pool syscalls and program output
420 debug("Seeding random number generator.");
421 debug("OpenSSL random status is now %i\n", RAND_status());
422 debug("%i bytes from system calls", (int)stir_from_system());
423 debug("%i bytes from programs", (int)stir_from_programs());
424 debug("OpenSSL random status is now %i\n", RAND_status());
426 #endif /* defined(EGD_SOCKET) || defined(RANDOM_POOL) */