c48ebde5ce
Add a wrapper function in sysdep to get random bytes, and required checks in configure.ac to select how to do it. The configure script tries, in order, getrandom(), getentropy() and reading from /dev/urandom.
110 lines
1.8 KiB
C
110 lines
1.8 KiB
C
/*
|
|
* BIRD Internet Routing Daemon -- Random Numbers
|
|
*
|
|
* (c) 2000 Martin Mares <mj@ucw.cz>
|
|
*
|
|
* Can be freely distributed and used under the terms of the GNU GPL.
|
|
*/
|
|
|
|
#include <stdlib.h>
|
|
#include <fcntl.h>
|
|
#include <unistd.h>
|
|
#include <errno.h>
|
|
|
|
#include "sysdep/config.h"
|
|
|
|
#ifdef HAVE_SYS_STAT_H
|
|
# include <sys/stat.h>
|
|
#endif
|
|
#ifdef HAVE_LINUX_RANDOM_H
|
|
# include <linux/random.h>
|
|
#endif
|
|
#if defined(HAVE_SYS_RANDOM_H) && (defined(HAVE_GETRANDOM) || defined(HAVE_GETENTROPY))
|
|
# include <sys/random.h>
|
|
#endif
|
|
|
|
#include "nest/bird.h"
|
|
|
|
u32
|
|
random_u32(void)
|
|
{
|
|
long int rand_low, rand_high;
|
|
|
|
rand_low = random();
|
|
rand_high = random();
|
|
return (rand_low & 0xffff) | ((rand_high & 0xffff) << 16);
|
|
}
|
|
|
|
void
|
|
random_init()
|
|
{
|
|
char buf;
|
|
/* get a single random byte to trip any errors early */
|
|
random_bytes(&buf, sizeof(buf));
|
|
}
|
|
|
|
#if defined(HAVE_GETRANDOM) || defined(HAVE_GENTROPY)
|
|
int
|
|
random_bytes(char *buf, size_t size)
|
|
{
|
|
int n;
|
|
int flags = 0;
|
|
while (0 < size) {
|
|
#if defined(HAVE_GETRANDOM)
|
|
n = getrandom(buf, size, flags);
|
|
#else
|
|
n = getentropy(buf, size);
|
|
#endif
|
|
if (n < 0) {
|
|
if (errno == EINTR)
|
|
continue;
|
|
die("Couldn't get random bytes: %m");
|
|
}
|
|
buf += n;
|
|
size -= n;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
void random_close(void) {}
|
|
|
|
#else
|
|
|
|
static int urandom_fd = -1;
|
|
int random_bytes(char *buf, size_t size)
|
|
{
|
|
int n;
|
|
|
|
if (urandom_fd < 0)
|
|
{
|
|
urandom_fd = open("/dev/urandom", O_RDONLY);
|
|
if (urandom_fd < 0)
|
|
die("Couldn't open /dev/urandom: %m");
|
|
}
|
|
|
|
do
|
|
{
|
|
n = read(urandom_fd, buf, size);
|
|
if (n <= 0) {
|
|
if (errno == EINTR)
|
|
continue;
|
|
die("Couldn't read from /dev/urandom: %m");
|
|
}
|
|
buf += n;
|
|
size -= n;
|
|
} while (size > 0);
|
|
|
|
return 0;
|
|
}
|
|
|
|
void
|
|
random_close(void)
|
|
{
|
|
if (urandom_fd >= 0) {
|
|
close(urandom_fd);
|
|
urandom_fd = -1;
|
|
}
|
|
}
|
|
#endif
|