lib/hcrypto/rand-timer.c

   1 /*
   2  * Copyright (c) 1995, 1996, 1997, 1999, 2007 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * 3. Neither the name of the Institute nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #include <config.h>
  35 #include <roken.h>
  36
  37 #include <rand.h>
  38
  39 #include "randi.h"
  40
  41 #ifndef WIN32 /* don't bother with this on windows */
  42
  43 static volatile int counter;
  44 static volatile unsigned char *gdata; /* Global data */
  45 static volatile int igdata;     /* Index into global data */
  46 static int gsize;
  47
  48 static
  49 RETSIGTYPE
  50 sigALRM(int sig)
  51 {
  52     if (igdata < gsize)
  53         gdata[igdata++] ^= counter & 0xff;
  54
  55 #ifndef HAVE_SIGACTION
  56     signal(SIGALRM, sigALRM); /* Reinstall SysV signal handler */
  57 #endif
  58     SIGRETURN(0);
  59 }
  60
  61 #ifndef HAVE_SETITIMER
  62 static void
  63 pacemaker(struct timeval *tv)
  64 {
  65     fd_set fds;
  66     pid_t pid;
  67     pid = getppid();
  68     while(1){
  69         FD_ZERO(&fds);
  70         FD_SET(0, &fds);
  71         select(1, &fds, NULL, NULL, tv);
  72         kill(pid, SIGALRM);
  73     }
  74 }
  75 #endif
  76
  77 #ifdef HAVE_SIGACTION
  78 /* XXX ugly hack, should perhaps use function from roken */
  79 static RETSIGTYPE
  80 (*fake_signal(int sig, RETSIGTYPE (*f)(int)))(int)
  81 {
  82     struct sigaction sa, osa;
  83     sa.sa_handler = f;
  84     sa.sa_flags = 0;
  85     sigemptyset(&sa.sa_mask);
  86     sigaction(sig, &sa, &osa);
  87     return osa.sa_handler;
  88 }
  89 #define signal(S, F) fake_signal((S), (F))
  90 #endif
  91
  92 #endif /* WIN32*/
  93
  94 /*
  95  *
  96  */
  97
  98 static void
  99 timer_seed(const void *indata, int size)
 100 {
 101 }
 102
 103 static int
 104 timer_bytes(unsigned char *outdata, int size)
 105 {
 106 #ifdef WIN32
 107     return 0;
 108 #else /* WIN32 */
 109     struct itimerval tv, otv;
 110     RETSIGTYPE (*osa)(int);
 111     int i, j;
 112 #ifndef HAVE_SETITIMER
 113     RETSIGTYPE (*ochld)(int);
 114     pid_t pid;
 115 #endif
 116
 117     gdata = outdata;
 118     gsize = size;
 119     igdata = 0;
 120
 121     osa = signal(SIGALRM, sigALRM);
 122
 123     /* Start timer */
 124     tv.it_value.tv_sec = 0;
 125     tv.it_value.tv_usec = 10 * 1000; /* 10 ms */
 126     tv.it_interval = tv.it_value;
 127 #ifdef HAVE_SETITIMER
 128     setitimer(ITIMER_REAL, &tv, &otv);
 129 #else
 130     ochld = signal(SIGCHLD, SIG_IGN);
 131     pid = fork();
 132     if(pid == -1){
 133         signal(SIGCHLD, ochld != SIG_ERR ? ochld : SIG_DFL);
 134         des_not_rand_data(data, size);
 135         return;
 136     }
 137     if(pid == 0)
 138         pacemaker(&tv.it_interval);
 139 #endif
 140
 141     for(i = 0; i < 4; i++) {
 142         for (igdata = 0; igdata < size;) /* igdata++ in sigALRM */
 143             counter++;
 144         for (j = 0; j < size; j++) /* Only use 2 bits each lap */
 145             gdata[j] = (gdata[j]>>2) | (gdata[j]<<6);
 146     }
 147 #ifdef HAVE_SETITIMER
 148     setitimer(ITIMER_REAL, &otv, 0);
 149 #else
 150     kill(pid, SIGKILL);
 151     while(waitpid(pid, NULL, 0) != pid);
 152     signal(SIGCHLD, ochld != SIG_ERR ? ochld : SIG_DFL);
 153 #endif
 154     signal(SIGALRM, osa != SIG_ERR ? osa : SIG_DFL);
 155
 156     return 1;
 157 #endif
 158 }
 159
 160 static void
 161 timer_cleanup(void)
 162 {
 163 }
 164
 165 static void
 166 timer_add(const void *indata, int size, double entropi)
 167 {
 168 }
 169
 170 static int
 171 timer_pseudorand(unsigned char *outdata, int size)
 172 {
 173     return timer_bytes(outdata, size);
 174 }
 175
 176 static int
 177 timer_status(void)
 178 {
 179 #ifdef WIN32
 180     return 0;
 181 #else
 182     return 1;
 183 #endif
 184 }
 185
 186 #if defined(__GNUC__) || (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901)
 187 const RAND_METHOD hc_rand_timer_method = {
 188     .seed = timer_seed,
 189     .bytes = timer_bytes,
 190     .cleanup = timer_cleanup,
 191     .add = timer_add,
 192     .pseudorand = timer_pseudorand,
 193     .status = timer_status
 194 };
 195 #else
 196 const RAND_METHOD hc_rand_timer_method = {
 197     timer_seed,
 198     timer_bytes,
 199     timer_cleanup,
 200     timer_add,
 201     timer_pseudorand,
 202     timer_status
 203 };
 204 #endif
 205
 206 const RAND_METHOD *
 207 RAND_timer_method(void)
 208 {
 209     return &hc_rand_timer_method;
 210 }