438 lines
13 KiB
C
438 lines
13 KiB
C
/*
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* Copyright 2011-2018 The OpenSSL Project Authors. All Rights Reserved.
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*
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* Licensed under the OpenSSL license (the "License"). You may not use
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* this file except in compliance with the License. You can obtain a copy
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* in the file LICENSE in the source distribution or at
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* https://www.openssl.org/source/license.html
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*/
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#include <stdlib.h>
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#include <string.h>
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#include <openssl/crypto.h>
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#include <openssl/err.h>
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#include <openssl/rand.h>
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#include "internal/thread_once.h"
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#include "internal/thread_once.h"
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#include "rand_lcl.h"
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/*
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* Implementation of NIST SP 800-90A CTR DRBG.
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*/
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static void inc_128(RAND_DRBG_CTR *ctr)
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{
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int i;
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unsigned char c;
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unsigned char *p = &ctr->V[15];
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for (i = 0; i < 16; i++, p--) {
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c = *p;
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c++;
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*p = c;
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if (c != 0) {
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/* If we didn't wrap around, we're done. */
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break;
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}
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}
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}
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static void ctr_XOR(RAND_DRBG_CTR *ctr, const unsigned char *in, size_t inlen)
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{
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size_t i, n;
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if (in == NULL || inlen == 0)
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return;
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/*
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* Any zero padding will have no effect on the result as we
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* are XORing. So just process however much input we have.
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*/
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n = inlen < ctr->keylen ? inlen : ctr->keylen;
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for (i = 0; i < n; i++)
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ctr->K[i] ^= in[i];
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if (inlen <= ctr->keylen)
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return;
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n = inlen - ctr->keylen;
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if (n > 16) {
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/* Should never happen */
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n = 16;
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}
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for (i = 0; i < n; i++)
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ctr->V[i] ^= in[i + ctr->keylen];
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}
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/*
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* Process a complete block using BCC algorithm of SP 800-90A 10.3.3
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*/
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__owur static int ctr_BCC_block(RAND_DRBG_CTR *ctr, unsigned char *out,
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const unsigned char *in)
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{
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int i, outlen = AES_BLOCK_SIZE;
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for (i = 0; i < 16; i++)
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out[i] ^= in[i];
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if (!EVP_CipherUpdate(ctr->ctx_df, out, &outlen, out, AES_BLOCK_SIZE)
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|| outlen != AES_BLOCK_SIZE)
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return 0;
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return 1;
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}
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/*
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* Handle several BCC operations for as much data as we need for K and X
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*/
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__owur static int ctr_BCC_blocks(RAND_DRBG_CTR *ctr, const unsigned char *in)
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{
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if (!ctr_BCC_block(ctr, ctr->KX, in)
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|| !ctr_BCC_block(ctr, ctr->KX + 16, in))
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return 0;
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if (ctr->keylen != 16 && !ctr_BCC_block(ctr, ctr->KX + 32, in))
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return 0;
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return 1;
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}
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/*
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* Initialise BCC blocks: these have the value 0,1,2 in leftmost positions:
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* see 10.3.1 stage 7.
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*/
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__owur static int ctr_BCC_init(RAND_DRBG_CTR *ctr)
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{
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memset(ctr->KX, 0, 48);
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memset(ctr->bltmp, 0, 16);
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if (!ctr_BCC_block(ctr, ctr->KX, ctr->bltmp))
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return 0;
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ctr->bltmp[3] = 1;
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if (!ctr_BCC_block(ctr, ctr->KX + 16, ctr->bltmp))
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return 0;
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if (ctr->keylen != 16) {
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ctr->bltmp[3] = 2;
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if (!ctr_BCC_block(ctr, ctr->KX + 32, ctr->bltmp))
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return 0;
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}
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return 1;
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}
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/*
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* Process several blocks into BCC algorithm, some possibly partial
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*/
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__owur static int ctr_BCC_update(RAND_DRBG_CTR *ctr,
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const unsigned char *in, size_t inlen)
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{
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if (in == NULL || inlen == 0)
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return 1;
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/* If we have partial block handle it first */
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if (ctr->bltmp_pos) {
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size_t left = 16 - ctr->bltmp_pos;
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/* If we now have a complete block process it */
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if (inlen >= left) {
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memcpy(ctr->bltmp + ctr->bltmp_pos, in, left);
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if (!ctr_BCC_blocks(ctr, ctr->bltmp))
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return 0;
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ctr->bltmp_pos = 0;
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inlen -= left;
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in += left;
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}
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}
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/* Process zero or more complete blocks */
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for (; inlen >= 16; in += 16, inlen -= 16) {
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if (!ctr_BCC_blocks(ctr, in))
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return 0;
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}
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/* Copy any remaining partial block to the temporary buffer */
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if (inlen > 0) {
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memcpy(ctr->bltmp + ctr->bltmp_pos, in, inlen);
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ctr->bltmp_pos += inlen;
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}
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return 1;
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}
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__owur static int ctr_BCC_final(RAND_DRBG_CTR *ctr)
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{
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if (ctr->bltmp_pos) {
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memset(ctr->bltmp + ctr->bltmp_pos, 0, 16 - ctr->bltmp_pos);
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if (!ctr_BCC_blocks(ctr, ctr->bltmp))
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return 0;
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}
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return 1;
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}
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__owur static int ctr_df(RAND_DRBG_CTR *ctr,
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const unsigned char *in1, size_t in1len,
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const unsigned char *in2, size_t in2len,
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const unsigned char *in3, size_t in3len)
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{
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static unsigned char c80 = 0x80;
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size_t inlen;
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unsigned char *p = ctr->bltmp;
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int outlen = AES_BLOCK_SIZE;
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if (!ctr_BCC_init(ctr))
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return 0;
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if (in1 == NULL)
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in1len = 0;
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if (in2 == NULL)
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in2len = 0;
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if (in3 == NULL)
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in3len = 0;
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inlen = in1len + in2len + in3len;
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/* Initialise L||N in temporary block */
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*p++ = (inlen >> 24) & 0xff;
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*p++ = (inlen >> 16) & 0xff;
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*p++ = (inlen >> 8) & 0xff;
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*p++ = inlen & 0xff;
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/* NB keylen is at most 32 bytes */
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*p++ = 0;
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*p++ = 0;
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*p++ = 0;
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*p = (unsigned char)((ctr->keylen + 16) & 0xff);
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ctr->bltmp_pos = 8;
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if (!ctr_BCC_update(ctr, in1, in1len)
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|| !ctr_BCC_update(ctr, in2, in2len)
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|| !ctr_BCC_update(ctr, in3, in3len)
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|| !ctr_BCC_update(ctr, &c80, 1)
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|| !ctr_BCC_final(ctr))
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return 0;
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/* Set up key K */
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if (!EVP_CipherInit_ex(ctr->ctx, ctr->cipher, NULL, ctr->KX, NULL, 1))
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return 0;
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/* X follows key K */
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if (!EVP_CipherUpdate(ctr->ctx, ctr->KX, &outlen, ctr->KX + ctr->keylen,
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AES_BLOCK_SIZE)
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|| outlen != AES_BLOCK_SIZE)
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return 0;
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if (!EVP_CipherUpdate(ctr->ctx, ctr->KX + 16, &outlen, ctr->KX,
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AES_BLOCK_SIZE)
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|| outlen != AES_BLOCK_SIZE)
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return 0;
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if (ctr->keylen != 16)
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if (!EVP_CipherUpdate(ctr->ctx, ctr->KX + 32, &outlen, ctr->KX + 16,
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AES_BLOCK_SIZE)
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|| outlen != AES_BLOCK_SIZE)
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return 0;
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return 1;
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}
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/*
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* NB the no-df Update in SP800-90A specifies a constant input length
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* of seedlen, however other uses of this algorithm pad the input with
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* zeroes if necessary and have up to two parameters XORed together,
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* so we handle both cases in this function instead.
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*/
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__owur static int ctr_update(RAND_DRBG *drbg,
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const unsigned char *in1, size_t in1len,
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const unsigned char *in2, size_t in2len,
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const unsigned char *nonce, size_t noncelen)
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{
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RAND_DRBG_CTR *ctr = &drbg->data.ctr;
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int outlen = AES_BLOCK_SIZE;
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/* correct key is already set up. */
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inc_128(ctr);
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if (!EVP_CipherUpdate(ctr->ctx, ctr->K, &outlen, ctr->V, AES_BLOCK_SIZE)
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|| outlen != AES_BLOCK_SIZE)
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return 0;
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/* If keylen longer than 128 bits need extra encrypt */
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if (ctr->keylen != 16) {
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inc_128(ctr);
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if (!EVP_CipherUpdate(ctr->ctx, ctr->K+16, &outlen, ctr->V,
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AES_BLOCK_SIZE)
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|| outlen != AES_BLOCK_SIZE)
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return 0;
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}
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inc_128(ctr);
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if (!EVP_CipherUpdate(ctr->ctx, ctr->V, &outlen, ctr->V, AES_BLOCK_SIZE)
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|| outlen != AES_BLOCK_SIZE)
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return 0;
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/* If 192 bit key part of V is on end of K */
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if (ctr->keylen == 24) {
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memcpy(ctr->V + 8, ctr->V, 8);
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memcpy(ctr->V, ctr->K + 24, 8);
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}
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if ((drbg->flags & RAND_DRBG_FLAG_CTR_NO_DF) == 0) {
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/* If no input reuse existing derived value */
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if (in1 != NULL || nonce != NULL || in2 != NULL)
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if (!ctr_df(ctr, in1, in1len, nonce, noncelen, in2, in2len))
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return 0;
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/* If this a reuse input in1len != 0 */
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if (in1len)
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ctr_XOR(ctr, ctr->KX, drbg->seedlen);
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} else {
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ctr_XOR(ctr, in1, in1len);
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ctr_XOR(ctr, in2, in2len);
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}
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if (!EVP_CipherInit_ex(ctr->ctx, ctr->cipher, NULL, ctr->K, NULL, 1))
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return 0;
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return 1;
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}
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__owur static int drbg_ctr_instantiate(RAND_DRBG *drbg,
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const unsigned char *entropy, size_t entropylen,
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const unsigned char *nonce, size_t noncelen,
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const unsigned char *pers, size_t perslen)
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{
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RAND_DRBG_CTR *ctr = &drbg->data.ctr;
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if (entropy == NULL)
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return 0;
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memset(ctr->K, 0, sizeof(ctr->K));
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memset(ctr->V, 0, sizeof(ctr->V));
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if (!EVP_CipherInit_ex(ctr->ctx, ctr->cipher, NULL, ctr->K, NULL, 1))
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return 0;
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if (!ctr_update(drbg, entropy, entropylen, pers, perslen, nonce, noncelen))
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return 0;
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return 1;
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}
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__owur static int drbg_ctr_reseed(RAND_DRBG *drbg,
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const unsigned char *entropy, size_t entropylen,
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const unsigned char *adin, size_t adinlen)
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{
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if (entropy == NULL)
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return 0;
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if (!ctr_update(drbg, entropy, entropylen, adin, adinlen, NULL, 0))
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return 0;
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return 1;
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}
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__owur static int drbg_ctr_generate(RAND_DRBG *drbg,
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unsigned char *out, size_t outlen,
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const unsigned char *adin, size_t adinlen)
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{
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RAND_DRBG_CTR *ctr = &drbg->data.ctr;
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if (adin != NULL && adinlen != 0) {
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if (!ctr_update(drbg, adin, adinlen, NULL, 0, NULL, 0))
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return 0;
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/* This means we reuse derived value */
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if ((drbg->flags & RAND_DRBG_FLAG_CTR_NO_DF) == 0) {
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adin = NULL;
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adinlen = 1;
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}
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} else {
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adinlen = 0;
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}
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for ( ; ; ) {
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int outl = AES_BLOCK_SIZE;
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inc_128(ctr);
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if (outlen < 16) {
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/* Use K as temp space as it will be updated */
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if (!EVP_CipherUpdate(ctr->ctx, ctr->K, &outl, ctr->V,
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AES_BLOCK_SIZE)
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|| outl != AES_BLOCK_SIZE)
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return 0;
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memcpy(out, ctr->K, outlen);
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break;
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}
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if (!EVP_CipherUpdate(ctr->ctx, out, &outl, ctr->V, AES_BLOCK_SIZE)
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|| outl != AES_BLOCK_SIZE)
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return 0;
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out += 16;
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outlen -= 16;
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if (outlen == 0)
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break;
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}
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if (!ctr_update(drbg, adin, adinlen, NULL, 0, NULL, 0))
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return 0;
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return 1;
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}
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static int drbg_ctr_uninstantiate(RAND_DRBG *drbg)
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{
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EVP_CIPHER_CTX_free(drbg->data.ctr.ctx);
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EVP_CIPHER_CTX_free(drbg->data.ctr.ctx_df);
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OPENSSL_cleanse(&drbg->data.ctr, sizeof(drbg->data.ctr));
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return 1;
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}
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static RAND_DRBG_METHOD drbg_ctr_meth = {
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drbg_ctr_instantiate,
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drbg_ctr_reseed,
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drbg_ctr_generate,
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drbg_ctr_uninstantiate
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};
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int drbg_ctr_init(RAND_DRBG *drbg)
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{
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RAND_DRBG_CTR *ctr = &drbg->data.ctr;
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size_t keylen;
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switch (drbg->type) {
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default:
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/* This can't happen, but silence the compiler warning. */
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return 0;
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case NID_aes_128_ctr:
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keylen = 16;
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ctr->cipher = EVP_aes_128_ecb();
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break;
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case NID_aes_192_ctr:
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keylen = 24;
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ctr->cipher = EVP_aes_192_ecb();
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break;
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case NID_aes_256_ctr:
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keylen = 32;
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ctr->cipher = EVP_aes_256_ecb();
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break;
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}
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drbg->meth = &drbg_ctr_meth;
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ctr->keylen = keylen;
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if (ctr->ctx == NULL)
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ctr->ctx = EVP_CIPHER_CTX_new();
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if (ctr->ctx == NULL)
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return 0;
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drbg->strength = keylen * 8;
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drbg->seedlen = keylen + 16;
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if ((drbg->flags & RAND_DRBG_FLAG_CTR_NO_DF) == 0) {
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/* df initialisation */
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static const unsigned char df_key[32] = {
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0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07,
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0x08,0x09,0x0a,0x0b,0x0c,0x0d,0x0e,0x0f,
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0x10,0x11,0x12,0x13,0x14,0x15,0x16,0x17,
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0x18,0x19,0x1a,0x1b,0x1c,0x1d,0x1e,0x1f
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};
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if (ctr->ctx_df == NULL)
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ctr->ctx_df = EVP_CIPHER_CTX_new();
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if (ctr->ctx_df == NULL)
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return 0;
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/* Set key schedule for df_key */
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if (!EVP_CipherInit_ex(ctr->ctx_df, ctr->cipher, NULL, df_key, NULL, 1))
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return 0;
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drbg->min_entropylen = ctr->keylen;
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drbg->max_entropylen = DRBG_MINMAX_FACTOR * drbg->min_entropylen;
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drbg->min_noncelen = drbg->min_entropylen / 2;
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drbg->max_noncelen = DRBG_MINMAX_FACTOR * drbg->min_noncelen;
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drbg->max_perslen = DRBG_MAX_LENGTH;
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drbg->max_adinlen = DRBG_MAX_LENGTH;
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} else {
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drbg->min_entropylen = drbg->seedlen;
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drbg->max_entropylen = drbg->seedlen;
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/* Nonce not used */
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drbg->min_noncelen = 0;
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drbg->max_noncelen = 0;
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drbg->max_perslen = drbg->seedlen;
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drbg->max_adinlen = drbg->seedlen;
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}
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drbg->max_request = 1 << 16;
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return 1;
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}
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