+++ /dev/null
-/*
- * This file is part of PowerDNS or dnsdist.
- * Copyright -- PowerDNS.COM B.V. and its contributors
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of version 2 of the GNU General Public License as
- * published by the Free Software Foundation.
- *
- * In addition, for the avoidance of any doubt, permission is granted to
- * link this program with OpenSSL and to (re)distribute the binaries
- * produced as the result of such linking.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
- */
-#ifdef HAVE_CONFIG_H
-#include "config.h"
-#endif
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <fcntl.h>
-#include <unistd.h>
-#include <cstdlib>
-#include <string>
-#include "dns_random.hh"
-#include "arguments.hh"
-#include "logger.hh"
-
-#if defined(HAVE_RANDOMBYTES_STIR)
-#include <sodium.h>
-#endif
-#if defined(HAVE_RAND_BYTES)
-#include <openssl/rand.h>
-#endif
-#if defined(HAVE_GETRANDOM)
-#include <sys/random.h>
-#endif
-
-static enum DNS_RNG {
- RNG_UNINITIALIZED = 0,
- RNG_SODIUM,
- RNG_OPENSSL,
- RNG_GETRANDOM,
- RNG_ARC4RANDOM,
- RNG_URANDOM,
- RNG_KISS,
-} chosen_rng
- = RNG_UNINITIALIZED;
-
-static int urandom_fd = -1;
-
-#if defined(HAVE_KISS_RNG)
-/* KISS is intended for development use only */
-static unsigned int kiss_seed;
-static uint32_t kiss_z, kiss_w, kiss_jsr, kiss_jcong;
-
-static void
-kiss_init(unsigned int seed)
-{
- kiss_seed = seed;
- kiss_jsr = 0x5eed5eed; /* simply mustn't be 0 */
- kiss_z = 1 ^ (kiss_w = kiss_jcong = seed); /* w=z=0 is bad, see Rose */
-}
-
-static unsigned int
-kiss_rand(void)
-{
- kiss_z = 36969 * (kiss_z & 65535) + (kiss_z >> 16);
- kiss_w = 18000 * (kiss_w & 65535) + (kiss_w >> 16);
- kiss_jcong = 69069 * kiss_jcong + 1234567;
- kiss_jsr ^= (kiss_jsr << 13); /* <<17, >>13 gives cycle length 2^28.2 max */
- kiss_jsr ^= (kiss_jsr >> 17); /* <<13, >>17 gives maximal cycle length */
- kiss_jsr ^= (kiss_jsr << 5);
- return (((kiss_z << 16) + kiss_w) ^ kiss_jcong) + kiss_jsr;
-}
-#endif
-
-static void dns_random_setup(bool force = false)
-{
- string rdev;
- string rng;
- /* check if selection has been done */
- if (chosen_rng > RNG_UNINITIALIZED && !force) {
- return;
- }
-
-/* XXX: A horrible hack to allow using dns_random in places where arguments are not available.
- Forces /dev/urandom usage
-*/
-#if defined(USE_URANDOM_ONLY)
- chosen_rng = RNG_URANDOM;
- rdev = "/dev/urandom";
-#else
- rng = ::arg()["rng"];
- rdev = ::arg()["entropy-source"];
- if (rng == "auto") { // NOLINT: I see no way to avoid repeating blocks reported by clang-tidy
-#if defined(HAVE_GETRANDOM)
- chosen_rng = RNG_GETRANDOM;
-#elif defined(HAVE_ARC4RANDOM)
- chosen_rng = RNG_ARC4RANDOM;
-#elif defined(HAVE_RANDOMBYTES_STIR)
- chosen_rng = RNG_SODIUM;
-#elif defined(HAVE_RAND_BYTES)
- chosen_rng = RNG_OPENSSL;
-#else
- chosen_rng = RNG_URANDOM;
-#endif
-#if defined(HAVE_RANDOMBYTES_STIR)
- }
- else if (rng == "sodium") {
- chosen_rng = RNG_SODIUM;
-#endif
-#if defined(HAVE_RAND_BYTES)
- }
- else if (rng == "openssl") {
- chosen_rng = RNG_OPENSSL;
-#endif
-#if defined(HAVE_GETRANDOM)
- }
- else if (rng == "getrandom") {
- chosen_rng = RNG_GETRANDOM;
-#endif
-#if defined(HAVE_ARC4RANDOM)
- }
- else if (rng == "arc4random") {
- chosen_rng = RNG_ARC4RANDOM;
-#endif
- }
- else if (rng == "urandom") {
- chosen_rng = RNG_URANDOM;
-#if defined(HAVE_KISS_RNG)
- }
- else if (rng == "kiss") {
- chosen_rng = RNG_KISS;
- g_log << Logger::Warning << "kiss rng should not be used in production environment" << std::endl;
-#endif
- }
- else {
- throw std::runtime_error("Unsupported rng '" + rng + "'");
- }
-
-#if defined(HAVE_RANDOMBYTES_STIR)
- if (chosen_rng == RNG_SODIUM) {
- if (sodium_init() == -1) {
- throw std::runtime_error("Unable to initialize sodium crypto library");
- }
- /* make sure it's set up */
- randombytes_stir();
- }
-#endif
-
-#if defined(HAVE_GETRANDOM)
- if (chosen_rng == RNG_GETRANDOM) {
- char buf = 0;
- // some systems define getrandom but it does not really work, e.g. because it's
- // not present in kernel.
- if (getrandom(&buf, sizeof(buf), 0) == -1 && errno != EINTR) {
- g_log << Logger::Warning << "getrandom() failed: " << stringerror() << ", falling back to " + rdev << std::endl;
- chosen_rng = RNG_URANDOM;
- }
- }
-#endif
-
-#if defined(HAVE_RAND_BYTES)
- if (chosen_rng == RNG_OPENSSL) {
- int ret = 0;
- unsigned char buf = 0;
- if ((ret = RAND_bytes(&buf, sizeof(buf))) == -1) {
- throw std::runtime_error("RAND_bytes not supported by current SSL engine");
- }
- if (ret == 0) {
- throw std::runtime_error("Openssl RNG was not seeded");
- }
- }
-#endif
-#endif /* USE_URANDOM_ONLY */
- if (chosen_rng == RNG_URANDOM) {
- urandom_fd = open(rdev.c_str(), O_RDONLY);
- if (urandom_fd == -1) {
- throw std::runtime_error("Cannot open " + rdev + ": " + stringerror());
- }
- }
-#if defined(HAVE_KISS_RNG)
- if (chosen_rng == RNG_KISS) {
- int fileDesc = open(rdev.c_str(), O_RDONLY);
- if (fileDesc == -1) {
- throw std::runtime_error("Cannot open " + rdev + ": " + stringerror());
- }
- unsigned int seed = 0;
- if (read(urandom_fd, &seed, sizeof(seed)) < 0) {
- (void)close(fileDesc);
- throw std::runtime_error("Cannot read random device");
- }
- kiss_init(seed);
- (void)close(fileDesc);
- }
-#endif
-}
-
-void dns_random_init(const string& data __attribute__((unused)), bool force)
-{
- dns_random_setup(force);
- (void)dns_random(1);
- // init should occur already in dns_random_setup
- // this interface is only for KISS
-#if defined(HAVE_KISS_RNG)
- unsigned int seed;
- if (chosen_rng != RNG_KISS)
- return;
- if (data.size() != 16)
- throw std::runtime_error("invalid seed");
- seed = (data[0] + (data[1] << 8) + (data[2] << 16) + (data[3] << 24)) ^ (data[4] + (data[5] << 8) + (data[6] << 16) + (data[7] << 24)) ^ (data[8] + (data[9] << 8) + (data[10] << 16) + (data[11] << 24)) ^ (data[12] + (data[13] << 8) + (data[14] << 16) + (data[15] << 24));
- kiss_init(seed);
-#endif
-}
-
-uint32_t dns_random_uint32()
-{
- if (chosen_rng == RNG_UNINITIALIZED) {
- dns_random_setup();
- }
-
- switch (chosen_rng) {
- case RNG_UNINITIALIZED:
- throw std::runtime_error("Unreachable at " __FILE__ ":" + std::to_string(__LINE__)); // cannot be reached
- case RNG_SODIUM:
-#if defined(HAVE_RANDOMBYTES_STIR) && !defined(USE_URANDOM_ONLY)
- return randombytes_random();
-#else
- throw std::runtime_error("Unreachable at " __FILE__ ":" + std::to_string(__LINE__)); // cannot be reached
-#endif /* RND_SODIUM */
- case RNG_OPENSSL: {
-#if defined(HAVE_RAND_BYTES) && !defined(USE_URANDOM_ONLY)
- uint32_t num = 0;
- if (RAND_bytes(reinterpret_cast<unsigned char*>(&num), sizeof(num)) < 1) { // NOLINT: API
- throw std::runtime_error("Openssl RNG was not seeded");
- }
- return num;
-#else
- throw std::runtime_error("Unreachable at " __FILE__ ":" + std::to_string(__LINE__)); // cannot be reached
-#endif /* RNG_OPENSSL */
- }
- case RNG_GETRANDOM: {
-#if defined(HAVE_GETRANDOM) && !defined(USE_URANDOM_ONLY)
- uint32_t num = 0;
- do {
- auto got = getrandom(&num, sizeof(num), 0);
- if (got == -1 && errno == EINTR) {
- continue;
- }
- if (got != sizeof(num)) {
- throw std::runtime_error("getrandom() failed: " + stringerror());
- }
- break;
- } while (true);
- return num;
-#else
- throw std::runtime_error("Unreachable at " __FILE__ ":" + std::to_string(__LINE__)); // cannot be reached
-#endif
- }
- case RNG_ARC4RANDOM:
-#if defined(HAVE_ARC4RANDOM) && !defined(USE_URANDOM_ONLY)
- return arc4random();
-#else
- throw std::runtime_error("Unreachable at " __FILE__ ":" + std::to_string(__LINE__)); // cannot be reached
-#endif
- case RNG_URANDOM: {
- uint32_t num = 0;
- size_t attempts = 5;
- ssize_t got = read(urandom_fd, &num, sizeof(num));
- do {
- if (got < 0) {
- if (errno == EINTR) {
- continue;
- }
- throw std::runtime_error("Cannot read random device");
- }
- if (static_cast<size_t>(got) != sizeof(num)) {
- /* short read, let's retry */
- if (attempts == 0) {
- throw std::runtime_error("Too many short reads on random device");
- }
- attempts--;
- continue;
- }
- break;
- } while (true);
- return num;
- }
-#if defined(HAVE_KISS_RNG)
- case RNG_KISS: {
- uint32_t num = kiss_rand();
- return num;
- }
-#endif
- default:
- throw std::runtime_error("Unreachable at " __FILE__ ":" + std::to_string(__LINE__)); // cannot be reached
- };
-}
-
-uint32_t dns_random(uint32_t upper_bound)
-{
- if (chosen_rng == RNG_UNINITIALIZED) {
- dns_random_setup();
- }
-
- if (upper_bound < 2) {
- return 0;
- }
-
- unsigned int min = pdns::random_minimum_acceptable_value(upper_bound);
-
- switch (chosen_rng) {
- case RNG_UNINITIALIZED:
- throw std::runtime_error("Unreachable at " __FILE__ ":" + std::to_string(__LINE__)); // cannot be reached
- case RNG_SODIUM:
-#if defined(HAVE_RANDOMBYTES_STIR) && !defined(USE_URANDOM_ONLY)
- return randombytes_uniform(upper_bound);
-#else
- throw std::runtime_error("Unreachable at " __FILE__ ":" + std::to_string(__LINE__)); // cannot be reached
-#endif /* RND_SODIUM */
- case RNG_OPENSSL: {
-#if defined(HAVE_RAND_BYTES) && !defined(USE_URANDOM_ONLY)
- uint32_t num = 0;
- do {
- if (RAND_bytes(reinterpret_cast<unsigned char*>(&num), sizeof(num)) < 1) { // NOLINT: API
- throw std::runtime_error("Openssl RNG was not seeded");
- }
- } while (num < min);
-
- return num % upper_bound;
-#else
- throw std::runtime_error("Unreachable at " __FILE__ ":" + std::to_string(__LINE__)); // cannot be reached
-#endif /* RNG_OPENSSL */
- }
- case RNG_GETRANDOM: {
-#if defined(HAVE_GETRANDOM) && !defined(USE_URANDOM_ONLY)
- uint32_t num = 0;
- do {
- auto got = getrandom(&num, sizeof(num), 0);
- if (got == -1 && errno == EINTR) {
- continue;
- }
- if (got != sizeof(num)) {
- throw std::runtime_error("getrandom() failed: " + stringerror());
- }
- } while (num < min);
-
- return num % upper_bound;
-#else
- throw std::runtime_error("Unreachable at " __FILE__ ":" + std::to_string(__LINE__)); // cannot be reached
-#endif
- }
- case RNG_ARC4RANDOM:
-#if defined(HAVE_ARC4RANDOM) && !defined(USE_URANDOM_ONLY)
- return arc4random_uniform(upper_bound);
-#else
- throw std::runtime_error("Unreachable at " __FILE__ ":" + std::to_string(__LINE__)); // cannot be reached
-#endif
- case RNG_URANDOM: {
- uint32_t num = 0;
- size_t attempts = 5;
- do {
- ssize_t got = read(urandom_fd, &num, sizeof(num));
- if (got < 0) {
- if (errno == EINTR) {
- continue;
- }
- throw std::runtime_error("Cannot read random device");
- }
- if (static_cast<size_t>(got) != sizeof(num)) {
- /* short read, let's retry */
- if (attempts == 0) {
- throw std::runtime_error("Too many short reads on random device");
- }
- attempts--;
- continue;
- }
- } while (num < min);
-
- return num % upper_bound;
- }
-#if defined(HAVE_KISS_RNG)
- case RNG_KISS: {
- uint32_t num = 0;
- do {
- num = kiss_rand();
- } while (num < min);
-
- return num % upper_bound;
- }
-#endif
- default:
- throw std::runtime_error("Unreachable at " __FILE__ ":" + std::to_string(__LINE__)); // cannot be reached
- };
-}
-
-uint16_t dns_random_uint16()
-{
- return dns_random_uint32() & 0xffff;
-}
projects / thirdparty / pdns.git / commitdiff
