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.
36 # include <openssl/rand.h>
37 # include <openssl/sha.h>
40 # include <ssl/rand.h>
48 # define offsetof(type, member) ((size_t) &((type *)0)->member)
50 /* Collect entropy from EGD */
51 void get_random_bytes(unsigned char *buf, int len)
53 static int egd_socket = -1;
55 char egd_message[2] = { 0x02, 0x00 };
56 struct sockaddr_un addr;
59 memset(&addr, '\0', sizeof(addr));
60 addr.sun_family = AF_UNIX;
62 /* FIXME: compile time check? */
63 if (sizeof(EGD_SOCKET) > sizeof(addr.sun_path))
64 fatal("Random pool path is too long");
66 strcpy(addr.sun_path, EGD_SOCKET);
68 addr_len = offsetof(struct sockaddr_un, sun_path) + sizeof(EGD_SOCKET);
70 if (egd_socket == -1) {
71 egd_socket = socket(AF_UNIX, SOCK_STREAM, 0);
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));
79 fatal("Too many bytes to read from EGD");
81 /* Send blocking read request to EGD */
84 c = atomicio(write, egd_socket, egd_message, sizeof(egd_message));
86 fatal("Couldn't write to EGD socket \"%s\": %s", EGD_SOCKET, strerror(errno));
88 c = atomicio(read, egd_socket, buf, len);
90 fatal("Couldn't read from EGD socket \"%s\": %s", EGD_SOCKET, strerror(errno));
94 #else /* !EGD_SOCKET */
96 /* Collect entropy from /dev/urandom or pipe */
97 void get_random_bytes(unsigned char *buf, int len)
99 static int random_pool = -1;
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));
108 c = atomicio(read, random_pool, buf, len);
110 fatal("Couldn't read from random pool \"%s\": %s", RANDOM_POOL, strerror(errno));
112 #endif /* RANDOM_POOL */
113 #endif /* EGD_SOCKET */
115 #if !defined(EGD_SOCKET) && !defined(RANDOM_POOL)
117 * FIXME: proper entropy estimations. All current values are guesses
118 * FIXME: Need timeout for slow moving programs
119 * FIXME: More entropy sources
122 double stir_from_system(void);
123 double stir_from_programs(void);
124 double stir_gettimeofday(double entropy_estimate);
125 double stir_clock(double entropy_estimate);
126 double stir_rusage(int who, double entropy_estimate);
127 double hash_output_from_command(const char *path, const char **args, char *hash);
131 /* Proportion of data that is entropy */
133 /* Path to executable */
135 /* argv to pass to executable */
139 entropy_source_t entropy_sources[] = {
141 { 0.002, PROG_LS, { "ls", "-alni", "/var/log", NULL } },
142 { 0.002, PROG_LS, { "ls", "-alni", "/var/adm", NULL } },
143 { 0.002, PROG_LS, { "ls", "-alni", "/var/mail", NULL } },
144 { 0.002, PROG_LS, { "ls", "-alni", "/var/spool/mail", NULL } },
145 { 0.002, PROG_LS, { "ls", "-alni", "/proc", NULL } },
146 { 0.002, PROG_LS, { "ls", "-alni", "/tmp", NULL } },
149 { 0.005, PROG_NETSTAT, { "netstat","-an", NULL, NULL } },
150 { 0.010, PROG_NETSTAT, { "netstat","-in", NULL, NULL } },
151 { 0.002, PROG_NETSTAT, { "netstat","-rn", NULL, NULL } },
152 { 0.002, PROG_NETSTAT, { "netstat","-s", NULL, NULL } },
155 { 0.002, PROG_ARP, { "arp","-a","-n", NULL } },
158 { 0.002, PROG_IFCONFIG, { "ifconfig", "-a", NULL, NULL } },
161 { 0.003, PROG_PS, { "ps", "laxww", NULL, NULL } },
162 { 0.003, PROG_PS, { "ps", "-al", NULL, NULL } },
163 { 0.003, PROG_PS, { "ps", "-efl", NULL, NULL } },
166 { 0.005, PROG_W, { "w", NULL, NULL, NULL } },
169 { 0.001, PROG_WHO, { "who","-i", NULL, NULL } },
172 { 0.001, PROG_LAST, { "last", NULL, NULL, NULL } },
175 { 0.001, PROG_LASTLOG, { "lastlog", NULL, NULL, NULL } },
178 { 0.010, PROG_DF, { "df", NULL, NULL, NULL } },
179 { 0.010, PROG_DF, { "df", "-i", NULL, NULL } },
182 { 0.010, PROG_VMSTAT, { "vmstat", NULL, NULL, NULL } },
185 { 0.001, PROG_UPTIME, { "uptime", NULL, NULL, NULL } },
188 { 0.001, PROG_IPCS, { "-a", NULL, NULL, NULL } },
191 { 0.001, PROG_TAIL, { "tail", "-200", "/var/log/messages", NULL, NULL } },
192 { 0.001, PROG_TAIL, { "tail", "-200", "/var/log/syslog", NULL, NULL } },
193 { 0.001, PROG_TAIL, { "tail", "-200", "/var/adm/messages", NULL, NULL } },
194 { 0.001, PROG_TAIL, { "tail", "-200", "/var/adm/syslog", NULL, NULL } },
195 { 0.001, PROG_TAIL, { "tail", "-200", "/var/log/maillog", NULL, NULL } },
196 { 0.001, PROG_TAIL, { "tail", "-200", "/var/adm/maillog", NULL, NULL } },
198 { 0.000, NULL, { NULL, NULL, NULL, NULL, NULL } },
202 stir_from_system(void)
204 double total_entropy_estimate;
207 total_entropy_estimate = 0;
210 RAND_add(&i, sizeof(i), 0.1);
211 total_entropy_estimate += 0.1;
214 RAND_add(&i, sizeof(i), 0.1);
215 total_entropy_estimate += 0.1;
218 RAND_add(&i, sizeof(i), 0.0);
220 RAND_add(&i, sizeof(i), 0.0);
222 total_entropy_estimate += stir_gettimeofday(1.0);
223 total_entropy_estimate += stir_clock(0.2);
224 total_entropy_estimate += stir_rusage(RUSAGE_SELF, 2.0);
226 return(total_entropy_estimate);
230 stir_from_programs(void)
234 double entropy_estimate;
235 double total_entropy_estimate;
236 char hash[SHA_DIGEST_LENGTH];
239 * Run through list of programs twice to catch differences
241 total_entropy_estimate = 0;
242 for(i = 0; i < 2; i++) {
244 while (entropy_sources[c].path != NULL) {
245 /* Hash output from command */
246 entropy_estimate = hash_output_from_command(entropy_sources[c].path,
247 entropy_sources[c].args, hash);
249 /* Scale back entropy estimate according to command's rate */
250 entropy_estimate *= entropy_sources[c].rate;
252 /* Upper bound of entropy estimate is SHA_DIGEST_LENGTH */
253 if (entropy_estimate > SHA_DIGEST_LENGTH)
254 entropy_estimate = SHA_DIGEST_LENGTH;
256 /* * Scale back estimates for subsequent passes through list */
257 entropy_estimate /= 10.0 * (i + 1.0);
260 RAND_add(hash, sizeof(hash), entropy_estimate);
262 /* FIXME: turn this off later */
264 debug("Got %0.2f bytes of entropy from %s", entropy_estimate,
265 entropy_sources[c].path);
268 total_entropy_estimate += entropy_estimate;
270 /* Execution times should be a little unpredictable */
271 total_entropy_estimate += stir_gettimeofday(0.05);
272 total_entropy_estimate += stir_clock(0.05);
273 total_entropy_estimate += stir_rusage(RUSAGE_SELF, 0.1);
274 total_entropy_estimate += stir_rusage(RUSAGE_CHILDREN, 0.1);
280 return(total_entropy_estimate);
284 stir_gettimeofday(double entropy_estimate)
288 if (gettimeofday(&tv, NULL) == -1)
289 fatal("Couldn't gettimeofday: %s", strerror(errno));
291 RAND_add(&tv, sizeof(tv), entropy_estimate);
293 return(entropy_estimate);
297 stir_clock(double entropy_estimate)
303 RAND_add(&c, sizeof(c), entropy_estimate);
305 return(entropy_estimate);
306 #else /* _HAVE_CLOCK */
308 #endif /* _HAVE_CLOCK */
312 stir_rusage(int who, double entropy_estimate)
314 #ifdef HAVE_GETRUSAGE
317 if (getrusage(who, &ru) == -1)
318 fatal("Couldn't getrusage: %s", strerror(errno));
320 RAND_add(&ru, sizeof(ru), 0.1);
322 return(entropy_estimate);
323 #else /* _HAVE_GETRUSAGE */
325 #endif /* _HAVE_GETRUSAGE */
329 hash_output_from_command(const char *path, const char **args, char *hash)
331 static int devnull = -1;
337 int total_bytes_read;
341 devnull = open("/dev/null", O_RDWR);
343 fatal("Couldn't open /dev/null: %s", strerror(errno));
347 fatal("Couldn't open pipe: %s", strerror(errno));
349 switch (pid = fork()) {
353 fatal("Couldn't fork: %s", strerror(errno));
366 execv(path, (char**)args);
367 debug("(child) Couldn't exec '%s': %s", path, strerror(errno));
369 default: /* Parent */
373 RAND_add(&pid, sizeof(&pid), 0.0);
377 /* Hash output from child */
379 total_bytes_read = 0;
380 while ((bytes_read = read(p[0], buf, sizeof(buf))) > 0) {
381 SHA1_Update(&sha, buf, bytes_read);
382 total_bytes_read += bytes_read;
383 RAND_add(&bytes_read, sizeof(&bytes_read), 0.0);
385 SHA1_Final(hash, &sha);
389 if (waitpid(pid, &status, 0) == -1) {
390 error("Couldn't wait for child '%s' completion: %s", path,
395 RAND_add(&status, sizeof(&status), 0.0);
397 if (!WIFEXITED(status) || (WEXITSTATUS(status) != 0))
400 return(total_bytes_read);
402 #endif /* defined(EGD_SOCKET) || defined(RANDOM_POOL) */
404 #if defined(EGD_SOCKET) || defined(RANDOM_POOL)
406 * Seed OpenSSL's random number pool from Kernel random number generator
414 debug("Seeding random number generator");
415 get_random_bytes(buf, sizeof(buf));
416 RAND_add(buf, sizeof(buf), sizeof(buf));
417 memset(buf, '\0', sizeof(buf));
419 #else /* defined(EGD_SOCKET) || defined(RANDOM_POOL) */
421 * Conditionally Seed OpenSSL's random number pool syscalls and program output
426 debug("Seeding random number generator.");
427 debug("OpenSSL random status is now %i\n", RAND_status());
428 debug("%i bytes from system calls", (int)stir_from_system());
429 debug("%i bytes from programs", (int)stir_from_programs());
430 debug("OpenSSL random status is now %i\n", RAND_status());
432 #endif /* defined(EGD_SOCKET) || defined(RANDOM_POOL) */