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66a3ce2ec1f028dcac32485ed228eb59f938e461
wolfssl/ctaocrypt/src/random.c
John Safranek 66a3ce2ec1 added SHA-256 based RNG when setting NO_RC4 compile flag
2012-11-27 22:17:25 -08:00

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/* random.c
*
* Copyright (C) 2006-2012 Sawtooth Consulting Ltd.
*
* This file is part of CyaSSL.
*
* CyaSSL is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* CyaSSL 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
/* on HPUX 11 you may need to install /dev/random see
http://h20293.www2.hp.com/portal/swdepot/displayProductInfo.do?productNumber=KRNG11I
*/
#include <cyassl/ctaocrypt/random.h>
#include <cyassl/ctaocrypt/error.h>
#ifdef NO_RC4
#include <cyassl/ctaocrypt/sha256.h>
#ifdef NO_INLINE
#include <cyassl/ctaocrypt/misc.h>
#else
#include <ctaocrypt/src/misc.c>
#endif
#endif
#if defined(USE_WINDOWS_API)
#ifndef _WIN32_WINNT
#define _WIN32_WINNT 0x0400
#endif
#include <windows.h>
#include <wincrypt.h>
#else
#ifndef NO_DEV_RANDOM
#include <fcntl.h>
#ifndef EBSNET
#include <unistd.h>
#endif
#else
/* include headers that may be needed to get good seed */
#endif
#endif /* USE_WINDOWS_API */
#ifdef NO_RC4
/* Start NIST DRBG code */
#define OUTPUT_BLOCK_LEN (256/8)
#define MAX_REQUEST_LEN (0x1000)
#define MAX_STRING_LEN (0x100000000)
#define RESEED_MAX (0x100000000000LL)
#define ENTROPY_SZ 256
#define DBRG_SUCCESS 0
#define DBRG_ERROR 1
#define DBRG_NEED_RESEED 2
enum {
dbrgInitC = 0,
dbrgReseed = 1,
dbrgGenerateW = 2,
dbrgGenerateH = 3,
dbrgInitV
};
static int Hash_df(byte* out, word32 outSz, byte type, byte* inA, word32 inASz,
byte* inB, word32 inBSz, byte* inC, word32 inCSz)
{
byte ctr;
int i;
int len;
Sha256 sha;
byte digest[SHA256_DIGEST_SIZE];
word32 bits = (outSz * 8); // reverse byte order
#ifdef LITTLE_ENDIAN_ORDER
bits = ByteReverseWord32(bits);
#endif
len = (outSz / SHA256_DIGEST_SIZE)
+ ((outSz % SHA256_DIGEST_SIZE) ? 1 : 0);
for (i = 0, ctr = 1; i < len; i++, ctr++)
{
InitSha256(&sha);
Sha256Update(&sha, &ctr, sizeof(ctr));
Sha256Update(&sha, (byte*)&bits, sizeof(bits));
/* churning V is the only string that doesn't have
* the type added */
if (type != dbrgInitV)
Sha256Update(&sha, &type, sizeof(type));
Sha256Update(&sha, inA, inASz);
if (inB != NULL && inBSz > 0)
Sha256Update(&sha, inB, inBSz);
if (inC != NULL && inCSz > 0)
Sha256Update(&sha, inC, inCSz);
Sha256Final(&sha, digest);
if (outSz > SHA256_DIGEST_SIZE) {
XMEMCPY(out, digest, SHA256_DIGEST_SIZE);
outSz -= SHA256_DIGEST_SIZE;
out += SHA256_DIGEST_SIZE;
}
else {
XMEMCPY(out, digest, outSz);
}
}
XMEMSET(digest, 0, SHA256_DIGEST_SIZE);
XMEMSET(&sha, 0, sizeof(sha));
return DBRG_SUCCESS;
}
static int Hash_DBRG_Reseed(RNG* rng, byte* entropy, word32 entropySz)
{
byte seed[DBRG_SEED_LEN];
Hash_df(seed, sizeof(seed), dbrgInitV, rng->V, sizeof(rng->V),
entropy, entropySz, NULL, 0);
XMEMCPY(rng->V, seed, sizeof(rng->V));
XMEMSET(seed, 0, sizeof(seed));
Hash_df(rng->C, sizeof(rng->C), dbrgInitC, rng->V, sizeof(rng->V),
NULL, 0, NULL, 0);
rng->reseed_ctr = 1;
return 0;
}
static INLINE void array_add_one(byte* data, word32 dataSz)
{
int i;
for (i = dataSz - 1; i >= 0; i--)
{
data[i]++;
if (data[i] != 0) break;
}
}
static void Hash_gen(byte* out, word32 outSz, byte* V)
{
Sha256 sha;
byte data[DBRG_SEED_LEN];
byte digest[SHA256_DIGEST_SIZE];
int i;
int len = (outSz / SHA256_DIGEST_SIZE)
+ ((outSz % SHA256_DIGEST_SIZE) ? 1 : 0);
XMEMCPY(data, V, sizeof(data));
for (i = 0; i < len; i++) {
InitSha256(&sha);
Sha256Update(&sha, data, sizeof(data));
Sha256Final(&sha, digest);
if (outSz > SHA256_DIGEST_SIZE) {
XMEMCPY(out, digest, SHA256_DIGEST_SIZE);
outSz -= SHA256_DIGEST_SIZE;
out += SHA256_DIGEST_SIZE;
array_add_one(data, DBRG_SEED_LEN);
}
else {
XMEMCPY(out, digest, outSz);
}
}
XMEMSET(data, 0, sizeof(data));
XMEMSET(digest, 0, sizeof(digest));
XMEMSET(&sha, 0, sizeof(sha));
}
static INLINE void array_add(byte* d, word32 dLen, byte* s, word32 sLen)
{
word16 carry = 0;
if (dLen > 0 && sLen > 0 && dLen >= sLen) {
int sIdx, dIdx;
for (sIdx = dLen - 1, dIdx = dLen - 1; sIdx >= 0; dIdx--, sIdx--)
{
carry += d[dIdx] + s[sIdx];
d[dIdx] = carry;
carry >>= 8;
}
if (dIdx > 0)
d[dIdx] += carry;
}
}
static int Hash_DBRG_Generate(RNG* rng, byte* out, word32 outSz)
{
int ret;
if (rng->reseed_ctr != RESEED_MAX) {
Sha256 sha;
byte digest[SHA256_DIGEST_SIZE];
byte type = dbrgGenerateH;
Hash_gen(out, outSz, rng->V);
InitSha256(&sha);
Sha256Update(&sha, &type, sizeof(type));
Sha256Update(&sha, rng->V, sizeof(rng->V));
Sha256Final(&sha, digest);
array_add(rng->V, sizeof(rng->V), digest, sizeof(digest));
array_add(rng->V, sizeof(rng->V), rng->C, sizeof(rng->C));
array_add(rng->V, sizeof(rng->V),
(byte*)&rng->reseed_ctr, sizeof(rng->reseed_ctr));
rng->reseed_ctr++;
XMEMSET(&sha, 0, sizeof(sha));
XMEMSET(digest, 0, sizeof(digest));
ret = DBRG_SUCCESS;
}
else {
ret = DBRG_NEED_RESEED;
}
return ret;
}
static void Hash_DBRG_Instantiate(RNG* rng, byte* seed, word32 seedSz)
{
XMEMSET(rng, 0, sizeof(*rng));
Hash_df(rng->V, sizeof(rng->V), dbrgInitV, seed, seedSz, NULL, 0, NULL, 0);
Hash_df(rng->C, sizeof(rng->C), dbrgInitC, rng->V, sizeof(rng->V),
NULL, 0, NULL, 0);
rng->reseed_ctr = 1;
}
static int Hash_DBRG_Uninstantiate(RNG* rng)
{
int result = DBRG_ERROR;
if (rng != NULL) {
XMEMSET(rng, 0, sizeof(*rng));
result = DBRG_SUCCESS;
}
return result;
}
/* End NIST DRBG Code */
/* Get seed and key cipher */
int InitRng(RNG* rng)
{
byte entropy[ENTROPY_SZ];
int ret = DBRG_ERROR;
if (GenerateSeed(&rng->seed, entropy, sizeof(entropy)) == 0) {
Hash_DBRG_Instantiate(rng, entropy, sizeof(entropy));
ret = DBRG_SUCCESS;
}
XMEMSET(entropy, 0, sizeof(entropy));
return ret;
}
/* place a generated block in output */
void RNG_GenerateBlock(RNG* rng, byte* output, word32 sz)
{
int ret;
XMEMSET(output, 0, sz);
ret = Hash_DBRG_Generate(rng, output, sz);
if (ret == DBRG_NEED_RESEED) {
byte entropy[ENTROPY_SZ];
ret = GenerateSeed(&rng->seed, entropy, sizeof(entropy));
if (ret == 0) {
Hash_DBRG_Reseed(rng, entropy, sizeof(entropy));
ret = Hash_DBRG_Generate(rng, output, sz);
}
else
ret = DBRG_ERROR;
XMEMSET(entropy, 0, sizeof(entropy));
}
}
byte RNG_GenerateByte(RNG* rng)
{
byte b;
RNG_GenerateBlock(rng, &b, 1);
return b;
}
void FreeRng(RNG* rng)
{
Hash_DBRG_Uninstantiate(rng);
}
#else /* NO_RC4 */
/* Get seed and key cipher */
int InitRng(RNG* rng)
{
byte key[32];
byte junk[256];
int ret = GenerateSeed(&rng->seed, key, sizeof(key));
if (ret == 0) {
Arc4SetKey(&rng->cipher, key, sizeof(key));
RNG_GenerateBlock(rng, junk, sizeof(junk)); /* rid initial state */
}
return ret;
}
/* place a generated block in output */
void RNG_GenerateBlock(RNG* rng, byte* output, word32 sz)
{
XMEMSET(output, 0, sz);
Arc4Process(&rng->cipher, output, output, sz);
}
byte RNG_GenerateByte(RNG* rng)
{
byte b;
RNG_GenerateBlock(rng, &b, 1);
return b;
}
#endif /* NO_RC4 */
#if defined(USE_WINDOWS_API)
int GenerateSeed(OS_Seed* os, byte* output, word32 sz)
{
if(!CryptAcquireContext(&os->handle, 0, 0, PROV_RSA_FULL,
CRYPT_VERIFYCONTEXT))
return WINCRYPT_E;
if (!CryptGenRandom(os->handle, sz, output))
return CRYPTGEN_E;
CryptReleaseContext(os->handle, 0);
return 0;
}
#elif defined(THREADX) || defined(EBSNET)
#include "rtprand.h" /* rtp_rand () */
#include "rtptime.h" /* rtp_get_system_msec() */
int GenerateSeed(OS_Seed* os, byte* output, word32 sz)
{
int i;
rtp_srand(rtp_get_system_msec());
for (i = 0; i < sz; i++ ) {
output[i] = rtp_rand() % 256;
if ( (i % 8) == 7)
rtp_srand(rtp_get_system_msec());
}
return 0;
}
#elif defined(MICRIUM)
int GenerateSeed(OS_Seed* os, byte* output, word32 sz)
{
#if (NET_SECURE_MGR_CFG_EN == DEF_ENABLED)
NetSecure_InitSeed(output, sz);
#endif
return 0;
}
#elif defined(MBED)
/* write a real one !!!, just for testing board */
int GenerateSeed(OS_Seed* os, byte* output, word32 sz)
{
int i;
for (i = 0; i < sz; i++ )
output[i] = i;
return 0;
}
#elif defined(CYASSL_SAFERTOS)
#warning "write a real random seed!!!!, just for testing now"
int GenerateSeed(OS_Seed* os, byte* output, word32 sz)
{
int i;
for (i = 0; i < sz; i++ )
output[i] = i;
return 0;
}
#elif defined(FREESCALE_MQX)
#ifdef FREESCALE_K70_RNGA
/*
* Generates a RNG seed using the Random Number Generator Accelerator
* on the Kinetis K70. Documentation located in Chapter 37 of
* K70 Sub-Family Reference Manual (see Note 3 in the README for link).
*/
int GenerateSeed(OS_Seed* os, byte* output, word32 sz)
{
int i;
/* turn on RNGA module */
SIM_SCGC3 |= SIM_SCGC3_RNGA_MASK;
/* set SLP bit to 0 - "RNGA is not in sleep mode" */
RNG_CR &= ~RNG_CR_SLP_MASK;
/* set HA bit to 1 - "security violations masked" */
RNG_CR |= RNG_CR_HA_MASK;
/* set GO bit to 1 - "output register loaded with data" */
RNG_CR |= RNG_CR_GO_MASK;
for (i = 0; i < sz; i++) {
/* wait for RNG FIFO to be full */
while((RNG_SR & RNG_SR_OREG_LVL(0xF)) == 0) {}
/* get value */
output[i] = RNG_OR;
}
return 0;
}
#else
#warning "write a real random seed!!!!, just for testing now"
int GenerateSeed(OS_Seed* os, byte* output, word32 sz)
{
int i;
for (i = 0; i < sz; i++ )
output[i] = i;
return 0;
}
#endif /* FREESCALE_K70_RNGA */
#elif defined(NO_DEV_RANDOM)
#error "you need to write an os specific GenerateSeed() here"
#else /* !USE_WINDOWS_API && !THREADX && !MICRIUM && !NO_DEV_RANDOM */
/* may block */
int GenerateSeed(OS_Seed* os, byte* output, word32 sz)
{
int ret = 0;
os->fd = open("/dev/urandom",O_RDONLY);
if (os->fd == -1) {
/* may still have /dev/random */
os->fd = open("/dev/random",O_RDONLY);
if (os->fd == -1)
return OPEN_RAN_E;
}
while (sz) {
int len = (int)read(os->fd, output, sz);
if (len == -1) {
ret = READ_RAN_E;
break;
}
sz -= len;
output += len;
if (sz) {
#ifdef BLOCKING
sleep(0); /* context switch */
#else
ret = RAN_BLOCK_E;
break;
#endif
}
}
close(os->fd);
return ret;
}
#endif /* USE_WINDOWS_API */
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