12fb8c3d2d
Ported from the last FIPS release, with DUAL_EC and SHA1 and the self-tests removed. Since only AES-CTR is supported, other code simplifications were done. Removed the "entropy blocklen" concept. Moved internal functions to new include/internal/rand.h. Reviewed-by: Paul Dale <paul.dale@oracle.com> (Merged from https://github.com/openssl/openssl/pull/3789)
449 lines
12 KiB
C
449 lines
12 KiB
C
/*
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* Copyright 2011-2017 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 "rand_lcl.h"
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#include "internal/thread_once.h"
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/*
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* Mapping of NIST SP 800-90A DRBG to OpenSSL RAND_METHOD.
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*/
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/*
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* The default global DRBG and its auto-init/auto-cleanup.
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*/
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static DRBG_CTX ossl_drbg;
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static CRYPTO_ONCE ossl_drbg_init = CRYPTO_ONCE_STATIC_INIT;
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DEFINE_RUN_ONCE_STATIC(do_ossl_drbg_init)
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{
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ossl_drbg.lock = CRYPTO_THREAD_lock_new();
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return ossl_drbg.lock != NULL;
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}
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void rand_drbg_cleanup(void)
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{
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CRYPTO_THREAD_lock_free(ossl_drbg.lock);
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}
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static void inc_128(DRBG_CTR_CTX *cctx)
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{
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int i;
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unsigned char c;
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unsigned char *p = &cctx->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(DRBG_CTR_CTX *cctx, 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 < cctx->keylen ? inlen : cctx->keylen;
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for (i = 0; i < n; i++)
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cctx->K[i] ^= in[i];
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if (inlen <= cctx->keylen)
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return;
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n = inlen - cctx->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 < 16; i++)
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cctx->V[i] ^= in[i + cctx->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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static void ctr_BCC_block(DRBG_CTR_CTX *cctx, unsigned char *out,
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const unsigned char *in)
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{
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int i;
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for (i = 0; i < 16; i++)
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out[i] ^= in[i];
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AES_encrypt(out, out, &cctx->df_ks);
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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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static void ctr_BCC_blocks(DRBG_CTR_CTX *cctx, const unsigned char *in)
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{
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ctr_BCC_block(cctx, cctx->KX, in);
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ctr_BCC_block(cctx, cctx->KX + 16, in);
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if (cctx->keylen != 16)
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ctr_BCC_block(cctx, cctx->KX + 32, in);
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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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static void ctr_BCC_init(DRBG_CTR_CTX *cctx)
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{
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memset(cctx->KX, 0, 48);
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memset(cctx->bltmp, 0, 16);
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ctr_BCC_block(cctx, cctx->KX, cctx->bltmp);
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cctx->bltmp[3] = 1;
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ctr_BCC_block(cctx, cctx->KX + 16, cctx->bltmp);
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if (cctx->keylen != 16) {
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cctx->bltmp[3] = 2;
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ctr_BCC_block(cctx, cctx->KX + 32, cctx->bltmp);
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}
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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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static void ctr_BCC_update(DRBG_CTR_CTX *cctx,
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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;
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/* If we have partial block handle it first */
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if (cctx->bltmp_pos) {
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size_t left = 16 - cctx->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(cctx->bltmp + cctx->bltmp_pos, in, left);
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ctr_BCC_blocks(cctx, cctx->bltmp);
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cctx->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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ctr_BCC_blocks(cctx, in);
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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(cctx->bltmp + cctx->bltmp_pos, in, inlen);
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cctx->bltmp_pos += inlen;
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}
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}
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static void ctr_BCC_final(DRBG_CTR_CTX *cctx)
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{
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if (cctx->bltmp_pos) {
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memset(cctx->bltmp + cctx->bltmp_pos, 0, 16 - cctx->bltmp_pos);
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ctr_BCC_blocks(cctx, cctx->bltmp);
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}
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}
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static void ctr_df(DRBG_CTR_CTX *cctx,
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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 = cctx->bltmp;
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ctr_BCC_init(cctx);
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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)((cctx->keylen + 16) & 0xff);
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cctx->bltmp_pos = 8;
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ctr_BCC_update(cctx, in1, in1len);
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ctr_BCC_update(cctx, in2, in2len);
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ctr_BCC_update(cctx, in3, in3len);
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ctr_BCC_update(cctx, &c80, 1);
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ctr_BCC_final(cctx);
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/* Set up key K */
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AES_set_encrypt_key(cctx->KX, cctx->keylen * 8, &cctx->df_kxks);
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/* X follows key K */
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AES_encrypt(cctx->KX + cctx->keylen, cctx->KX, &cctx->df_kxks);
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AES_encrypt(cctx->KX, cctx->KX + 16, &cctx->df_kxks);
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if (cctx->keylen != 16)
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AES_encrypt(cctx->KX + 16, cctx->KX + 32, &cctx->df_kxks);
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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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* handle both cases in this function instead.
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*/
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static void ctr_update(DRBG_CTX *dctx,
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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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DRBG_CTR_CTX *cctx = &dctx->ctr;
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/* ks is already setup for correct key */
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inc_128(cctx);
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AES_encrypt(cctx->V, cctx->K, &cctx->ks);
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/* If keylen longer than 128 bits need extra encrypt */
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if (cctx->keylen != 16) {
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inc_128(cctx);
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AES_encrypt(cctx->V, cctx->K + 16, &cctx->ks);
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}
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inc_128(cctx);
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AES_encrypt(cctx->V, cctx->V, &cctx->ks);
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/* If 192 bit key part of V is on end of K */
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if (cctx->keylen == 24) {
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memcpy(cctx->V + 8, cctx->V, 8);
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memcpy(cctx->V, cctx->K + 24, 8);
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}
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if (dctx->flags & RAND_DRBG_FLAG_CTR_USE_DF) {
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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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ctr_df(cctx, in1, in1len, nonce, noncelen, in2, in2len);
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/* If this a reuse input in1len != 0 */
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if (in1len)
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ctr_XOR(cctx, cctx->KX, dctx->seedlen);
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} else {
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ctr_XOR(cctx, in1, in1len);
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ctr_XOR(cctx, in2, in2len);
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}
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AES_set_encrypt_key(cctx->K, dctx->strength, &cctx->ks);
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}
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int ctr_instantiate(DRBG_CTX *dctx,
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const unsigned char *ent, size_t entlen,
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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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DRBG_CTR_CTX *cctx = &dctx->ctr;
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memset(cctx->K, 0, sizeof(cctx->K));
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memset(cctx->V, 0, sizeof(cctx->V));
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AES_set_encrypt_key(cctx->K, dctx->strength, &cctx->ks);
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ctr_update(dctx, ent, entlen, pers, perslen, nonce, noncelen);
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return 1;
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}
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int ctr_reseed(DRBG_CTX *dctx,
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const unsigned char *ent, size_t entlen,
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const unsigned char *adin, size_t adinlen)
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{
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ctr_update(dctx, ent, entlen, adin, adinlen, NULL, 0);
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return 1;
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}
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int ctr_generate(DRBG_CTX *dctx,
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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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DRBG_CTR_CTX *cctx = &dctx->ctr;
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if (adin != NULL && adinlen != 0) {
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ctr_update(dctx, adin, adinlen, NULL, 0, NULL, 0);
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/* This means we reuse derived value */
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if (dctx->flags & RAND_DRBG_FLAG_CTR_USE_DF) {
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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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inc_128(cctx);
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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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AES_encrypt(cctx->V, cctx->K, &cctx->ks);
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memcpy(out, cctx->K, outlen);
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break;
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}
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AES_encrypt(cctx->V, out, &cctx->ks);
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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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ctr_update(dctx, adin, adinlen, NULL, 0, NULL, 0);
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return 1;
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}
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int ctr_uninstantiate(DRBG_CTX *dctx)
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{
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memset(&dctx->ctr, 0, sizeof(dctx->ctr));
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return 1;
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}
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int ctr_init(DRBG_CTX *dctx)
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{
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DRBG_CTR_CTX *cctx = &dctx->ctr;
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size_t keylen;
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switch (dctx->nid) {
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default:
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/* This can't happen, but silence the compiler warning. */
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return -1;
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case NID_aes_128_ctr:
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keylen = 16;
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break;
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case NID_aes_192_ctr:
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keylen = 24;
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break;
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case NID_aes_256_ctr:
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keylen = 32;
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break;
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}
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cctx->keylen = keylen;
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dctx->strength = keylen * 8;
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dctx->blocklength = 16;
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dctx->seedlen = keylen + 16;
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if (dctx->flags & RAND_DRBG_FLAG_CTR_USE_DF) {
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/* df initialisation */
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static 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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/* Set key schedule for df_key */
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AES_set_encrypt_key(df_key, dctx->strength, &cctx->df_ks);
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dctx->min_entropy = cctx->keylen;
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dctx->max_entropy = DRBG_MAX_LENGTH;
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dctx->min_nonce = dctx->min_entropy / 2;
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dctx->max_nonce = DRBG_MAX_LENGTH;
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dctx->max_pers = DRBG_MAX_LENGTH;
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dctx->max_adin = DRBG_MAX_LENGTH;
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} else {
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dctx->min_entropy = dctx->seedlen;
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dctx->max_entropy = dctx->seedlen;
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/* Nonce not used */
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dctx->min_nonce = 0;
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dctx->max_nonce = 0;
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dctx->max_pers = dctx->seedlen;
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dctx->max_adin = dctx->seedlen;
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}
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dctx->max_request = 1 << 16;
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dctx->reseed_interval = 1 << 24;
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return 1;
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}
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/*
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* The following function tie the DRBG code into the RAND_METHOD
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*/
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DRBG_CTX *RAND_DRBG_get_default(void)
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{
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if (!RUN_ONCE(&ossl_drbg_init, do_ossl_drbg_init))
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return NULL;
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return &ossl_drbg;
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}
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static int drbg_bytes(unsigned char *out, int count)
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{
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DRBG_CTX *dctx = RAND_DRBG_get_default();
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int ret = 0;
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CRYPTO_THREAD_write_lock(dctx->lock);
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do {
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size_t rcnt;
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if (count > (int)dctx->max_request)
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rcnt = dctx->max_request;
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else
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rcnt = count;
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ret = RAND_DRBG_generate(dctx, out, rcnt, 0, NULL, 0);
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if (!ret)
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goto err;
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out += rcnt;
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count -= rcnt;
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} while (count);
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ret = 1;
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err:
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CRYPTO_THREAD_unlock(dctx->lock);
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return ret;
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}
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static int drbg_status(void)
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{
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DRBG_CTX *dctx = RAND_DRBG_get_default();
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int ret;
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CRYPTO_THREAD_write_lock(dctx->lock);
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ret = dctx->status == DRBG_STATUS_READY ? 1 : 0;
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CRYPTO_THREAD_unlock(dctx->lock);
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return ret;
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}
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static void drbg_cleanup(void)
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{
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DRBG_CTX *dctx = RAND_DRBG_get_default();
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CRYPTO_THREAD_write_lock(dctx->lock);
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RAND_DRBG_uninstantiate(dctx);
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CRYPTO_THREAD_unlock(dctx->lock);
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}
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static const RAND_METHOD rand_drbg_meth =
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{
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NULL,
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drbg_bytes,
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drbg_cleanup,
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NULL,
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drbg_bytes,
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drbg_status
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};
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const RAND_METHOD *RAND_drbg(void)
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{
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return &rand_drbg_meth;
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}
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