1386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari/* 2386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * rand_source.c 3386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * 4386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * implements a random source based on /dev/random 5386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * 6386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * David A. McGrew 7386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * Cisco Systems, Inc. 8386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari */ 9386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari/* 10386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * 11386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * Copyright(c) 2001-2006 Cisco Systems, Inc. 12386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * All rights reserved. 13386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * 14386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * Redistribution and use in source and binary forms, with or without 15386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * modification, are permitted provided that the following conditions 16386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * are met: 17386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * 18386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * Redistributions of source code must retain the above copyright 19386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * notice, this list of conditions and the following disclaimer. 20386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * 21386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * Redistributions in binary form must reproduce the above 22386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * copyright notice, this list of conditions and the following 23386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * disclaimer in the documentation and/or other materials provided 24386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * with the distribution. 25386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * 26386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * Neither the name of the Cisco Systems, Inc. nor the names of its 27386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * contributors may be used to endorse or promote products derived 28386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * from this software without specific prior written permission. 29386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * 30386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 31386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 32386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 33386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 34386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, 35386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 36386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 37386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 38386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 39386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 40386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED 41386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * OF THE POSSIBILITY OF SUCH DAMAGE. 42386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * 43386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari */ 44386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari 45386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari#include "config.h" 46386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari 47386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari#ifdef DEV_URANDOM 48386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari# include <fcntl.h> /* for open() */ 49386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari# include <unistd.h> /* for close() */ 50386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari#elif defined(HAVE_RAND_S) 51386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari# define _CRT_RAND_S 52386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari# include <stdlib.h> 53386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari#else 54386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari# include <stdio.h> 55386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari#endif 56386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari 57386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari#include "rand_source.h" 58386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari 59386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari 60386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari/* 61386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * global dev_rand_fdes is file descriptor for /dev/random 62386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * 63386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * This variable is also used to indicate that the random source has 64386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * been initialized. When this variable is set to the value of the 65386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * #define RAND_SOURCE_NOT_READY, it indicates that the random source 66386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * is not ready to be used. The value of the #define 67386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * RAND_SOURCE_READY is for use whenever that variable is used as an 68386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * indicator of the state of the random source, but not as a file 69386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * descriptor. 70386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari */ 71386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari 72386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari#define RAND_SOURCE_NOT_READY (-1) 73386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari#define RAND_SOURCE_READY (17) 74386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari 75386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagaristatic int dev_random_fdes = RAND_SOURCE_NOT_READY; 76386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari 77386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari 78386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagarierr_status_t 79386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagarirand_source_init(void) { 80386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari if (dev_random_fdes >= 0) { 81386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari /* already open */ 82386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari return err_status_ok; 83386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari } 84386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari#ifdef DEV_URANDOM 85386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari /* open random source for reading */ 86386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari dev_random_fdes = open(DEV_URANDOM, O_RDONLY); 87386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari if (dev_random_fdes < 0) 88386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari return err_status_init_fail; 89386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari#elif defined(HAVE_RAND_S) 90386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari dev_random_fdes = RAND_SOURCE_READY; 91386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari#else 92386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari /* no random source available; let the user know */ 93386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari fprintf(stderr, "WARNING: no real random source present!\n"); 94386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari dev_random_fdes = RAND_SOURCE_READY; 95386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari#endif 96386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari return err_status_ok; 97386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari} 98386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari 99386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagarierr_status_t 100386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagarirand_source_get_octet_string(void *dest, uint32_t len) { 101386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari 102386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari /* 103386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * read len octets from /dev/random to dest, and 104386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * check return value to make sure enough octets were 105386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * written 106386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari */ 107386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari#ifdef DEV_URANDOM 108386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari if (read(dev_random_fdes, dest, len) != len) 109386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari return err_status_fail; 110386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari#elif defined(HAVE_RAND_S) 111386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari uint8_t *dst = (uint8_t *)dest; 112386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari while (len) 113386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari { 114386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari unsigned int val; 115386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari errno_t err = rand_s(&val); 116386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari 117386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari if (err != 0) 118386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari return err_status_fail; 119386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari 120386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari *dst++ = val & 0xff; 121386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari len--; 122386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari } 123386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari#else 124386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari /* Generic C-library (rand()) version */ 125386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari /* This is a random source of last resort */ 126386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari uint8_t *dst = (uint8_t *)dest; 127386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari while (len) 128386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari { 129386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari int val = rand(); 130386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari /* rand() returns 0-32767 (ugh) */ 131386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari /* Is this a good enough way to get random bytes? 132386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari It is if it passes FIPS-140... */ 133386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari *dst++ = val & 0xff; 134386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari len--; 135386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari } 136386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari#endif 137386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari return err_status_ok; 138386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari} 139386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari 140386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagarierr_status_t 141386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagarirand_source_deinit(void) { 142386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari if (dev_random_fdes < 0) 143386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari return err_status_dealloc_fail; /* well, we haven't really failed, * 144386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari * but there is something wrong */ 145386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari#ifdef DEV_URANDOM 146386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari close(dev_random_fdes); 147386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari#endif 148386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari dev_random_fdes = RAND_SOURCE_NOT_READY; 149386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari 150386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari return err_status_ok; 151386ce4d9144fc190797f4e43a31aeaf76ca2e373Param Reddappagari} 152