2 * Copyright 1995-2017 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the OpenSSL license (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
13 #include "internal/cryptlib.h"
14 #include <openssl/rand.h>
18 #if !(defined(OPENSSL_SYS_WINDOWS) || defined(OPENSSL_SYS_WIN32) || defined(OPENSSL_SYS_VMS) || defined(OPENSSL_SYS_VXWORKS) || defined(OPENSSL_SYS_UEFI))
20 # if (defined(OPENSSL_SYS_VXWORKS) || defined(OPENSSL_SYS_UEFI)) && \
21 !defined(OPENSSL_RAND_SEED_NONE)
22 # error "UEFI and VXWorks only support seeding NONE"
25 # if defined(OPENSSL_SYS_VOS)
27 # ifndef OPENSSL_RAND_SEED_OS
28 # error "Unsupported seeding method configured; must be os"
31 # if defined(OPENSSL_SYS_VOS_HPPA) && defined(OPENSSL_SYS_VOS_IA32)
32 # error "Unsupported HP-PA and IA32 at the same time."
34 # if !defined(OPENSSL_SYS_VOS_HPPA) && !defined(OPENSSL_SYS_VOS_IA32)
35 # error "Must have one of HP-PA or IA32"
39 * The following algorithm repeatedly samples the real-time clock (RTC) to
40 * generate a sequence of unpredictable data. The algorithm relies upon the
41 * uneven execution speed of the code (due to factors such as cache misses,
42 * interrupts, bus activity, and scheduling) and upon the rather large
43 * relative difference between the speed of the clock and the rate at which
46 * If this code is ported to an environment where execution speed is more
47 * constant or where the RTC ticks at a much slower rate, or the clock can be
48 * read with fewer instructions, it is likely that the results would be far
51 * As a precaution, we generate 4 times the minimum required amount of seed
63 # ifdef OPENSSL_SYS_VOS_HPPA
65 extern void s$sleep(long *_duration, short int *_code);
68 extern void s$sleep2(long long *_duration, short int *_code);
72 * Seed with the gid, pid, and uid, to ensure *some* variation between
73 * different processes.
76 RAND_add(&curr_gid, sizeof curr_gid, 0);
78 RAND_add(&curr_pid, sizeof curr_pid, 0);
80 RAND_add(&curr_uid, sizeof curr_uid, 0);
82 for (i = 0; i < (RANDOMNESS_NEEDED * 4); i++) {
84 * burn some cpu; hope for interrupts, cache collisions, bus
87 for (k = 0; k < 99; k++)
88 ts.tv_nsec = random();
90 # ifdef OPENSSL_SYS_VOS_HPPA
91 /* sleep for 1/1024 of a second (976 us). */
93 s$sleep(&duration, &code);
95 /* sleep for 1/65536 of a second (15 us). */
97 s$sleep2(&duration, &code);
100 /* Get wall clock time, take 8 bits. */
101 clock_gettime(CLOCK_REALTIME, &ts);
102 v = (unsigned char)(ts.tv_nsec & 0xFF);
103 RAND_add(&v, sizeof v, 1);
110 # if defined(OPENSSL_RAND_SEED_EGD) && \
111 (defined(OPENSSL_NO_EGD) || !defined(DEVRANDOM_EGD))
112 # error "Seeding uses EGD but EGD is turned off or no device given"
115 # if defined(OPENSSL_RAND_SEED_DEVRANDOM) && !defined(DEVRANDOM)
116 # error "Seeding uses urandom but DEVRANDOM is not configured"
119 # if defined(OPENSSL_RAND_SEED_OS)
120 # if defined(DEVRANDOM)
121 # define OPENSSL_RAND_SEED_DEVRANDOM
123 # error "OS seeding requires DEVRANDOM to be configured"
127 # if defined(OPENSSL_RAND_SEED_LIBRANDOM)
128 # error "librandom not (yet) supported"
133 # ifdef OPENSSL_RAND_SEED_NONE
137 char temp[RANDOMNESS_NEEDED];
138 # define TEMPSIZE (int)sizeof(temp)
140 # ifdef OPENSSL_RAND_SEED_RDTSC
144 # ifdef OPENSSL_RAND_SEED_RDCPU
149 # ifdef OPENSSL_RAND_SEED_EGD
151 static const char *paths[] = { DEVRANDOM_EGD, NULL };
154 for (i = 0; paths[i] != NULL; i++) {
155 if (RAND_query_egd_bytes(paths[i], temp, TEMPSIZE) == TEMPSIZE) {
156 RAND_add(temp, TEMPSIZE, TEMPSIZE);
164 # ifdef OPENSSL_RAND_SEED_DEVRANDOM
166 static const char *paths[] = { DEVRANDOM, NULL };
170 for (i = 0; paths[i] != NULL; i++) {
171 if ((fp = fopen(paths[i], "rb")) == NULL)
174 if (fread(temp, 1, TEMPSIZE, fp) == TEMPSIZE) {
175 RAND_add(temp, TEMPSIZE, TEMPSIZE);
184 # ifdef OPENSSL_RAND_SEED_GETRANDOM
186 int i = getrandom(temp, TEMPSIZE, 0);
189 RAND_add(temp, i, i);
196 OPENSSL_cleanse(temp, TEMPSIZE);
197 return ok > 0 ? 1 : 0;