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