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