| /* |
| * Copyright 2011-2020 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 "modes_local.h" |
| #include "internal/thread_once.h" |
| #include "rand_local.h" |
| |
| /* |
| * Implementation of NIST SP 800-90A CTR DRBG. |
| */ |
| |
| static void inc_128(RAND_DRBG_CTR *ctr) |
| { |
| unsigned char *p = &ctr->V[0]; |
| u32 n = 16, c = 1; |
| |
| do { |
| --n; |
| c += p[n]; |
| p[n] = (u8)c; |
| c >>= 8; |
| } while (n); |
| } |
| |
| 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 len) |
| { |
| int i, outlen = AES_BLOCK_SIZE; |
| |
| for (i = 0; i < len; i++) |
| out[i] ^= in[i]; |
| |
| if (!EVP_CipherUpdate(ctr->ctx_df, out, &outlen, out, len) |
| || outlen != len) |
| 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) |
| { |
| unsigned char in_tmp[48]; |
| unsigned char num_of_blk = 2; |
| |
| memcpy(in_tmp, in, 16); |
| memcpy(in_tmp + 16, in, 16); |
| if (ctr->keylen != 16) { |
| memcpy(in_tmp + 32, in, 16); |
| num_of_blk = 3; |
| } |
| return ctr_BCC_block(ctr, ctr->KX, in_tmp, AES_BLOCK_SIZE * num_of_blk); |
| } |
| |
| /* |
| * 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) |
| { |
| unsigned char bltmp[48] = {0}; |
| unsigned char num_of_blk; |
| |
| memset(ctr->KX, 0, 48); |
| num_of_blk = ctr->keylen == 16 ? 2 : 3; |
| bltmp[(AES_BLOCK_SIZE * 1) + 3] = 1; |
| bltmp[(AES_BLOCK_SIZE * 2) + 3] = 2; |
| return ctr_BCC_block(ctr, ctr->KX, bltmp, num_of_blk * AES_BLOCK_SIZE); |
| } |
| |
| /* |
| * 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_ecb, NULL, NULL, ctr->KX, NULL, -1)) |
| return 0; |
| /* X follows key K */ |
| if (!EVP_CipherUpdate(ctr->ctx_ecb, ctr->KX, &outlen, ctr->KX + ctr->keylen, |
| AES_BLOCK_SIZE) |
| || outlen != AES_BLOCK_SIZE) |
| return 0; |
| if (!EVP_CipherUpdate(ctr->ctx_ecb, ctr->KX + 16, &outlen, ctr->KX, |
| AES_BLOCK_SIZE) |
| || outlen != AES_BLOCK_SIZE) |
| return 0; |
| if (ctr->keylen != 16) |
| if (!EVP_CipherUpdate(ctr->ctx_ecb, 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; |
| unsigned char V_tmp[48], out[48]; |
| unsigned char len; |
| |
| /* correct key is already set up. */ |
| memcpy(V_tmp, ctr->V, 16); |
| inc_128(ctr); |
| memcpy(V_tmp + 16, ctr->V, 16); |
| if (ctr->keylen == 16) { |
| len = 32; |
| } else { |
| inc_128(ctr); |
| memcpy(V_tmp + 32, ctr->V, 16); |
| len = 48; |
| } |
| if (!EVP_CipherUpdate(ctr->ctx_ecb, out, &outlen, V_tmp, len) |
| || outlen != len) |
| return 0; |
| memcpy(ctr->K, out, ctr->keylen); |
| memcpy(ctr->V, out + ctr->keylen, 16); |
| |
| 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_ecb, NULL, NULL, ctr->K, NULL, -1) |
| || !EVP_CipherInit_ex(ctr->ctx_ctr, NULL, 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_ecb, NULL, NULL, ctr->K, NULL, -1)) |
| return 0; |
| |
| inc_128(ctr); |
| 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) |
| { |
| RAND_DRBG_CTR *ctr = &drbg->data.ctr; |
| |
| if (entropy == NULL) |
| return 0; |
| |
| inc_128(ctr); |
| if (!ctr_update(drbg, entropy, entropylen, adin, adinlen, NULL, 0)) |
| return 0; |
| return 1; |
| } |
| |
| static void ctr96_inc(unsigned char *counter) |
| { |
| u32 n = 12, c = 1; |
| |
| do { |
| --n; |
| c += counter[n]; |
| counter[n] = (u8)c; |
| c >>= 8; |
| } while (n); |
| } |
| |
| __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; |
| unsigned int ctr32, blocks; |
| int outl, buflen; |
| |
| if (adin != NULL && adinlen != 0) { |
| inc_128(ctr); |
| |
| 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; |
| } |
| |
| inc_128(ctr); |
| |
| if (outlen == 0) { |
| inc_128(ctr); |
| |
| if (!ctr_update(drbg, adin, adinlen, NULL, 0, NULL, 0)) |
| return 0; |
| return 1; |
| } |
| |
| memset(out, 0, outlen); |
| |
| do { |
| if (!EVP_CipherInit_ex(ctr->ctx_ctr, |
| NULL, NULL, NULL, ctr->V, -1)) |
| return 0; |
| |
| /*- |
| * outlen has type size_t while EVP_CipherUpdate takes an |
| * int argument and thus cannot be guaranteed to process more |
| * than 2^31-1 bytes at a time. We process such huge generate |
| * requests in 2^30 byte chunks, which is the greatest multiple |
| * of AES block size lower than or equal to 2^31-1. |
| */ |
| buflen = outlen > (1U << 30) ? (1U << 30) : outlen; |
| blocks = (buflen + 15) / 16; |
| |
| ctr32 = GETU32(ctr->V + 12) + blocks; |
| if (ctr32 < blocks) { |
| /* 32-bit counter overflow into V. */ |
| if (ctr32 != 0) { |
| blocks -= ctr32; |
| buflen = blocks * 16; |
| ctr32 = 0; |
| } |
| ctr96_inc(ctr->V); |
| } |
| PUTU32(ctr->V + 12, ctr32); |
| |
| if (!EVP_CipherUpdate(ctr->ctx_ctr, out, &outl, out, buflen) |
| || outl != buflen) |
| return 0; |
| |
| out += buflen; |
| outlen -= buflen; |
| } while (outlen); |
| |
| 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_ecb); |
| EVP_CIPHER_CTX_free(drbg->data.ctr.ctx_ctr); |
| 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_ecb = EVP_aes_128_ecb(); |
| ctr->cipher_ctr = EVP_aes_128_ctr(); |
| break; |
| case NID_aes_192_ctr: |
| keylen = 24; |
| ctr->cipher_ecb = EVP_aes_192_ecb(); |
| ctr->cipher_ctr = EVP_aes_192_ctr(); |
| break; |
| case NID_aes_256_ctr: |
| keylen = 32; |
| ctr->cipher_ecb = EVP_aes_256_ecb(); |
| ctr->cipher_ctr = EVP_aes_256_ctr(); |
| break; |
| } |
| |
| drbg->meth = &drbg_ctr_meth; |
| |
| ctr->keylen = keylen; |
| if (ctr->ctx_ecb == NULL) |
| ctr->ctx_ecb = EVP_CIPHER_CTX_new(); |
| if (ctr->ctx_ctr == NULL) |
| ctr->ctx_ctr = EVP_CIPHER_CTX_new(); |
| if (ctr->ctx_ecb == NULL || ctr->ctx_ctr == NULL |
| || !EVP_CipherInit_ex(ctr->ctx_ecb, |
| ctr->cipher_ecb, NULL, NULL, NULL, 1) |
| || !EVP_CipherInit_ex(ctr->ctx_ctr, |
| ctr->cipher_ctr, NULL, NULL, NULL, 1)) |
| return 0; |
| |
| drbg->meth = &drbg_ctr_meth; |
| 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_ecb, NULL, df_key, NULL, 1)) |
| return 0; |
| |
| drbg->min_entropylen = ctr->keylen; |
| drbg->max_entropylen = DRBG_MAX_LENGTH; |
| drbg->min_noncelen = drbg->min_entropylen / 2; |
| drbg->max_noncelen = DRBG_MAX_LENGTH; |
| 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; |
| } |