crypto/rand/rand_unix.c

   1 /*
   2  * Copyright 1995-2017 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   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
   8  */
   9
  10 #include "e_os.h"
  11 #include <stdio.h>
  12 #include "internal/cryptlib.h"
  13 #include <openssl/rand.h>
  14 #include "rand_lcl.h"
  15 #include <stdio.h>
  16
  17 #if !(defined(OPENSSL_SYS_WINDOWS) || defined(OPENSSL_SYS_WIN32) || defined(OPENSSL_SYS_VMS) || defined(OPENSSL_SYS_VXWORKS) || defined(OPENSSL_SYS_UEFI))
  18
  19 # if (defined(OPENSSL_SYS_VXWORKS) || defined(OPENSSL_SYS_UEFI)) && \
  20         !defined(OPENSSL_RAND_SEED_NONE)
  21 #  error "UEFI and VXWorks only support seeding NONE"
  22 # endif
  23
  24 # if defined(OPENSSL_SYS_VOS)
  25
  26 #  ifndef OPENSSL_RAND_SEED_OS
  27 #   error "Unsupported seeding method configured; must be os"
  28 #  endif
  29
  30 #  if defined(OPENSSL_SYS_VOS_HPPA) && defined(OPENSSL_SYS_VOS_IA32)
  31 #   error "Unsupported HP-PA and IA32 at the same time."
  32 #  endif
  33 #  if !defined(OPENSSL_SYS_VOS_HPPA) && !defined(OPENSSL_SYS_VOS_IA32)
  34 #   error "Must have one of HP-PA or IA32"
  35 #  endif
  36
  37 /*
  38  * The following algorithm repeatedly samples the real-time clock (RTC) to
  39  * generate a sequence of unpredictable data.  The algorithm relies upon the
  40  * uneven execution speed of the code (due to factors such as cache misses,
  41  * interrupts, bus activity, and scheduling) and upon the rather large
  42  * relative difference between the speed of the clock and the rate at which
  43  * it can be read.  If it is ported to an environment where execution speed
  44  * is more constant or where the RTC ticks at a much slower rate, or the
  45  * clock can be read with fewer instructions, it is likely that the results
  46  * would be far more predictable.  This should only be used for legacy
  47  * platforms.
  48  *
  49  * As a precaution, we generate four times the required amount of seed
  50  * data.
  51  */
  52 int RAND_poll_ex(RAND_poll_cb rand_add, void *arg)
  53 {
  54     short int code;
  55     gid_t curr_gid;
  56     pid_t curr_pid;
  57     uid_t curr_uid;
  58     int i, k;
  59     struct timespec ts;
  60     unsigned char v;
  61 #  ifdef OPENSSL_SYS_VOS_HPPA
  62     long duration;
  63     extern void s$sleep(long *_duration, short int *_code);
  64 #  else
  65     long long duration;
  66     extern void s$sleep2(long long *_duration, short int *_code);
  67 #  endif
  68
  69     /*
  70      * Seed with the gid, pid, and uid, to ensure *some* variation between
  71      * different processes.
  72      */
  73     curr_gid = getgid();
  74     rand_add(arg, &curr_gid, sizeof curr_gid, 0);
  75     curr_pid = getpid();
  76     rand_add(arg, &curr_pid, sizeof curr_pid, 0);
  77     curr_uid = getuid();
  78     rand_add(arg, &curr_uid, sizeof curr_uid, 0);
  79
  80     for (i = 0; i < (RANDOMNESS_NEEDED * 4); i++) {
  81         /*
  82          * burn some cpu; hope for interrupts, cache collisions, bus
  83          * interference, etc.
  84          */
  85         for (k = 0; k < 99; k++)
  86             ts.tv_nsec = random();
  87
  88 #  ifdef OPENSSL_SYS_VOS_HPPA
  89         /* sleep for 1/1024 of a second (976 us).  */
  90         duration = 1;
  91         s$sleep(&duration, &code);
  92 #  else
  93         /* sleep for 1/65536 of a second (15 us).  */
  94         duration = 1;
  95         s$sleep2(&duration, &code);
  96 #  endif
  97
  98         /* Get wall clock time, take 8 bits. */
  99         clock_gettime(CLOCK_REALTIME, &ts);
 100         v = (unsigned char)(ts.tv_nsec & 0xFF);
 101         rand_add(arg, &v, sizeof v, 1);
 102     }
 103     return 1;
 104 }
 105
 106 # else
 107
 108 #  if defined(OPENSSL_RAND_SEED_EGD) && \
 109         (defined(OPENSSL_NO_EGD) || !defined(DEVRANDOM_EGD))
 110 #   error "Seeding uses EGD but EGD is turned off or no device given"
 111 #  endif
 112
 113 #  if defined(OPENSSL_RAND_SEED_DEVRANDOM) && !defined(DEVRANDOM)
 114 #   error "Seeding uses urandom but DEVRANDOM is not configured"
 115 #  endif
 116
 117 #  if defined(OPENSSL_RAND_SEED_OS)
 118 #   if defined(DEVRANDOM)
 119 #    define OPENSSL_RAND_SEED_DEVRANDOM
 120 #   else
 121 #    error "OS seeding requires DEVRANDOM to be configured"
 122 #   endif
 123 #  endif
 124
 125 #  if defined(OPENSSL_RAND_SEED_LIBRANDOM)
 126 #   error "librandom not (yet) supported"
 127 #  endif
 128
 129 /*
 130  * Try the various seeding methods in turn, exit when succesful.
 131  */
 132 int RAND_poll_ex(RAND_poll_cb rand_add, void *arg)
 133 {
 134 #  ifdef OPENSSL_RAND_SEED_NONE
 135     return 0;
 136 #  else
 137     int ok = 1;
 138     char temp[RANDOMNESS_NEEDED];
 139 #   define TEMPSIZE (int)sizeof(temp)
 140
 141 #   ifdef OPENSSL_RAND_SEED_GETRANDOM
 142     {
 143         int i = getrandom(temp, TEMPSIZE, 0);
 144
 145         if (i >= 0) {
 146             rand_add(arg, temp, i, i);
 147             if (i == TEMPSIZE)
 148                 goto done;
 149         }
 150     }
 151 #   endif
 152
 153 #   if defined(OPENSSL_RAND_SEED_LIBRANDOM)
 154     {
 155         /* Not yet implemented. */
 156     }
 157 #   endif
 158
 159 #   ifdef OPENSSL_RAND_SEED_DEVRANDOM
 160     {
 161         static const char *paths[] = { DEVRANDOM, NULL };
 162         FILE *fp;
 163         int i;
 164
 165         for (i = 0; paths[i] != NULL; i++) {
 166             if ((fp = fopen(paths[i], "rb")) == NULL)
 167                 continue;
 168             setbuf(fp, NULL);
 169             if (fread(temp, 1, TEMPSIZE, fp) == TEMPSIZE) {
 170                 rand_add(arg, temp, TEMPSIZE, TEMPSIZE);
 171                 fclose(fp);
 172                 goto done;
 173             }
 174             fclose(fp);
 175         }
 176     }
 177 #   endif
 178
 179 #   ifdef OPENSSL_RAND_SEED_RDTSC
 180     rand_read_tsc(rand_add, arg);
 181 #   endif
 182
 183 #   ifdef OPENSSL_RAND_SEED_RDCPU
 184     if (rand_read_cpu(rand_add, arg))
 185         goto done;
 186 #   endif
 187
 188 #   ifdef OPENSSL_RAND_SEED_EGD
 189     {
 190         static const char *paths[] = { DEVRANDOM_EGD, NULL };
 191         int i;
 192
 193         for (i = 0; paths[i] != NULL; i++) {
 194             if (RAND_query_egd_bytes(paths[i], temp, TEMPSIZE) == TEMPSIZE) {
 195                 rand_add(arg, temp, TEMPSIZE, TEMPSIZE);
 196                 goto done;
 197             }
 198         }
 199     }
 200 #   endif
 201
 202     ok = 0;
 203
 204 done:
 205     OPENSSL_cleanse(temp, TEMPSIZE);
 206     return ok;
 207 #  endif
 208 }
 209 # endif
 210
 211 #endif