/* fips/rand/fips_drbg_ctr.c */
/* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
* project.
*/
/* ====================================================================
* Copyright (c) 2011 The OpenSSL Project. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. All advertising materials mentioning features or use of this
* software must display the following acknowledgment:
* "This product includes software developed by the OpenSSL Project
* for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
*
* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
* endorse or promote products derived from this software without
* prior written permission. For written permission, please contact
* licensing@OpenSSL.org.
*
* 5. Products derived from this software may not be called "OpenSSL"
* nor may "OpenSSL" appear in their names without prior written
* permission of the OpenSSL Project.
*
* 6. Redistributions of any form whatsoever must retain the following
* acknowledgment:
* "This product includes software developed by the OpenSSL Project
* for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
*
* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
* ====================================================================
*/
#include <stdlib.h>
#include <string.h>
#include <openssl/crypto.h>
#include <openssl/fips.h>
#include <openssl/fips_rand.h>
#include "fips_rand_lcl.h"
static void inc_128(DRBG_CTR_CTX * cctx)
{
int i;
unsigned char c;
unsigned char *p = cctx->V + 15;
for (i = 0; i < 16; i++) {
c = *p;
c++;
*p = c;
if (c)
return;
p--;
}
}
static void ctr_XOR(DRBG_CTR_CTX * cctx, const unsigned char *in,
size_t inlen)
{
size_t i, n;
/* Any zero padding will have no effect on the result as we
* are XORing. So just process however much input we have.
*/
if (!in || !inlen)
return;
if (inlen < cctx->keylen)
n = inlen;
else
n = cctx->keylen;
for (i = 0; i < n; i++)
cctx->K[i] ^= in[i];
if (inlen <= cctx->keylen)
return;
n = inlen - cctx->keylen;
/* Should never happen */
if (n > 16)
n = 16;
for (i = 0; i < 16; i++)
cctx->V[i] ^= in[i + cctx->keylen];
}
/* Process a complete block using BCC algorithm of SPP 800-90 10.4.3 */
static void ctr_BCC_block(DRBG_CTR_CTX * cctx, unsigned char *out,
const unsigned char *in)
{
int i;
for (i = 0; i < 16; i++)
out[i] ^= in[i];
AES_encrypt(out, out, &cctx->df_ks);
#if 0
fprintf(stderr, "BCC in+out\n");
BIO_dump_fp(stderr, in, 16);
BIO_dump_fp(stderr, out, 16);
#endif
}
/* Handle several BCC operations for as much data as we need for K and X */
static void ctr_BCC_blocks(DRBG_CTR_CTX * cctx, const unsigned char *in)
{
ctr_BCC_block(cctx, cctx->KX, in);
ctr_BCC_block(cctx, cctx->KX + 16, in);
if (cctx->keylen != 16)
ctr_BCC_block(cctx, cctx->KX + 32, in);
}
/* Initialise BCC blocks: these have the value 0,1,2 in leftmost positions:
* see 10.4.2 stage 7.
*/
static void ctr_BCC_init(DRBG_CTR_CTX * cctx)
{
memset(cctx->KX, 0, 48);
memset(cctx->bltmp, 0, 16);
ctr_BCC_block(cctx, cctx->KX, cctx->bltmp);
cctx->bltmp[3] = 1;
ctr_BCC_block(cctx, cctx->KX + 16, cctx->bltmp);
if (cctx->keylen != 16) {
cctx->bltmp[3] = 2;
ctr_BCC_block(cctx, cctx->KX + 32, cctx->bltmp);
}
}
/* Process several blocks into BCC algorithm, some possibly partial */
static void ctr_BCC_update(DRBG_CTR_CTX * cctx,
const unsigned char *in, size_t inlen)
{
if (!in || !inlen)
return;
/* If we have partial block handle it first */
if (cctx->bltmp_pos) {
size_t left = 16 - cctx->bltmp_pos;
/* If we now have a complete block process it */
if (inlen >= left) {
memcpy(cctx->bltmp + cctx->bltmp_pos, in, left);
ctr_BCC_blocks(cctx, cctx->bltmp);
cctx->bltmp_pos = 0;
inlen -= left;
in += left;
}
}
/* Process zero or more complete blocks */
while (inlen >= 16) {
ctr_BCC_blocks(cctx, in);
in += 16;
inlen -= 16;
}
/* Copy any remaining partial block to the temporary buffer */
if (inlen > 0) {
memcpy(cctx->bltmp + cctx->bltmp_pos, in, inlen);
cctx->bltmp_pos += inlen;
}
}
static void ctr_BCC_final(DRBG_CTR_CTX * cctx)
{
if (cctx->bltmp_pos) {
memset(cctx->bltmp + cctx->bltmp_pos, 0, 16 - cctx->bltmp_pos);
ctr_BCC_blocks(cctx, cctx->bltmp);
}
}
static void ctr_df(DRBG_CTR_CTX * cctx,
const unsigned char *in1, size_t in1len,
const unsigned char *in2, size_t in2len,
const unsigned char *in3, size_t in3len)
{
size_t inlen;
unsigned char *p = cctx->bltmp;
static unsigned char c80 = 0x80;
ctr_BCC_init(cctx);
if (!in1)
in1len = 0;
if (!in2)
in2len = 0;
if (!in3)
in3len = 0;
inlen = in1len + in2len + in3len;
/* Initialise L||N in temporary block */
*p++ = (inlen >> 24) & 0xff;
*p++ = (inlen >> 16) & 0xff;
*p++ = (inlen >> 8) & 0xff;
*p++ = inlen & 0xff;
/* NB keylen is at most 32 bytes */
*p++ = 0;
*p++ = 0;
*p++ = 0;
*p = (unsigned char)((cctx->keylen + 16) & 0xff);
cctx->bltmp_pos = 8;
ctr_BCC_update(cctx, in1, in1len);
ctr_BCC_update(cctx, in2, in2len);
ctr_BCC_update(cctx, in3, in3len);
ctr_BCC_update(cctx, &c80, 1);
ctr_BCC_final(cctx);
/* Set up key K */
AES_set_encrypt_key(cctx->KX, cctx->keylen * 8, &cctx->df_kxks);
/* X follows key K */
AES_encrypt(cctx->KX + cctx->keylen, cctx->KX, &cctx->df_kxks);
AES_encrypt(cctx->KX, cctx->KX + 16, &cctx->df_kxks);
if (cctx->keylen != 16)
AES_encrypt(cctx->KX + 16, cctx->KX + 32, &cctx->df_kxks);
#if 0
fprintf(stderr, "Output of ctr_df:\n");
BIO_dump_fp(stderr, cctx->KX, cctx->keylen + 16);
#endif
}
/* NB the no-df Update in SP800-90 specifies a constant input length
* of seedlen, however other uses of this algorithm pad the input with
* zeroes if necessary and have up to two parameters XORed together,
* handle both cases in this function instead.
*/
static void ctr_Update(DRBG_CTX *dctx,
const unsigned char *in1, size_t in1len,
const unsigned char *in2, size_t in2len,
const unsigned char *nonce, size_t noncelen)
{
DRBG_CTR_CTX *cctx = &dctx->d.ctr;
/* ks is already setup for correct key */
inc_128(cctx);
AES_encrypt(cctx->V, cctx->K, &cctx->ks);
/* If keylen longer than 128 bits need extra encrypt */
if (cctx->keylen != 16) {
inc_128(cctx);
AES_encrypt(cctx->V, cctx->K + 16, &cctx->ks);
}
inc_128(cctx);
AES_encrypt(cctx->V, cctx->V, &cctx->ks);
/* If 192 bit key part of V is on end of K */
if (cctx->keylen == 24) {
memcpy(cctx->V + 8, cctx->V, 8);
memcpy(cctx->V, cctx->K + 24, 8);
}
if (dctx->xflags & DRBG_FLAG_CTR_USE_DF) {
/* If no input reuse existing derived value */
if (in1 || nonce || in2)
ctr_df(cctx, in1, in1len, nonce, noncelen, in2, in2len);
/* If this a reuse input in1len != 0 */
if (in1len)
ctr_XOR(cctx, cctx->KX, dctx->seedlen);
} else {
ctr_XOR(cctx, in1, in1len);
ctr_XOR(cctx, in2, in2len);
}
AES_set_encrypt_key(cctx->K, dctx->strength, &cctx->ks);
#if 0
fprintf(stderr, "K+V after update is:\n");
BIO_dump_fp(stderr, cctx->K, cctx->keylen);
BIO_dump_fp(stderr, cctx->V, 16);
#endif
}
static int drbg_ctr_instantiate(DRBG_CTX *dctx,
const unsigned char *ent, size_t entlen,
const unsigned char *nonce, size_t noncelen,
const unsigned char *pers, size_t perslen)
{
DRBG_CTR_CTX *cctx = &dctx->d.ctr;
memset(cctx->K, 0, sizeof(cctx->K));
memset(cctx->V, 0, sizeof(cctx->V));
AES_set_encrypt_key(cctx->K, dctx->strength, &cctx->ks);
ctr_Update(dctx, ent, entlen, pers, perslen, nonce, noncelen);
return 1;
}
static int drbg_ctr_reseed(DRBG_CTX *dctx,
const unsigned char *ent, size_t entlen,
const unsigned char *adin, size_t adinlen)
{
ctr_Update(dctx, ent, entlen, adin, adinlen, NULL, 0);
return 1;
}
static int drbg_ctr_generate(DRBG_CTX *dctx,
unsigned char *out, size_t outlen,
const unsigned char *adin, size_t adinlen)
{
DRBG_CTR_CTX *cctx = &dctx->d.ctr;
if (adin && adinlen) {
ctr_Update(dctx, adin, adinlen, NULL, 0, NULL, 0);
/* This means we reuse derived value */
if (dctx->xflags & DRBG_FLAG_CTR_USE_DF) {
adin = NULL;
adinlen = 1;
}
} else
adinlen = 0;
for (;;) {
inc_128(cctx);
if (outlen < 16) {
/* Use K as temp space as it will be updated */
AES_encrypt(cctx->V, cctx->K, &cctx->ks);
memcpy(out, cctx->K, outlen);
break;
}
AES_encrypt(cctx->V, out, &cctx->ks);
out += 16;
outlen -= 16;
if (outlen == 0)
break;
}
ctr_Update(dctx, adin, adinlen, NULL, 0, NULL, 0);
return 1;
}
static int drbg_ctr_uninstantiate(DRBG_CTX *dctx)
{
memset(&dctx->d.ctr, 0, sizeof(DRBG_CTR_CTX));
return 1;
}
int fips_drbg_ctr_init(DRBG_CTX *dctx)
{
DRBG_CTR_CTX *cctx = &dctx->d.ctr;
size_t keylen;
switch (dctx->type) {
case NID_aes_128_ctr:
keylen = 16;
break;
case NID_aes_192_ctr:
keylen = 24;
break;
case NID_aes_256_ctr:
keylen = 32;
break;
default:
return -2;
}
dctx->instantiate = drbg_ctr_instantiate;
dctx->reseed = drbg_ctr_reseed;
dctx->generate = drbg_ctr_generate;
dctx->uninstantiate = drbg_ctr_uninstantiate;
cctx->keylen = keylen;
dctx->strength = keylen * 8;
dctx->blocklength = 16;
dctx->seedlen = keylen + 16;
if (dctx->xflags & DRBG_FLAG_CTR_USE_DF) {
/* df initialisation */
static unsigned char df_key[32] = {
0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f
};
/* Set key schedule for df_key */
AES_set_encrypt_key(df_key, dctx->strength, &cctx->df_ks);
dctx->min_entropy = cctx->keylen;
dctx->max_entropy = DRBG_MAX_LENGTH;
dctx->min_nonce = dctx->min_entropy / 2;
dctx->max_nonce = DRBG_MAX_LENGTH;
dctx->max_pers = DRBG_MAX_LENGTH;
dctx->max_adin = DRBG_MAX_LENGTH;
} else {
dctx->min_entropy = dctx->seedlen;
dctx->max_entropy = dctx->seedlen;
/* Nonce not used */
dctx->min_nonce = 0;
dctx->max_nonce = 0;
dctx->max_pers = dctx->seedlen;
dctx->max_adin = dctx->seedlen;
}
dctx->max_request = 1 << 16;
dctx->reseed_interval = 1 << 24;
return 1;
}