diff options
Diffstat (limited to 'crypto/rand/drbg_ctr.c')
| -rw-r--r-- | crypto/rand/drbg_ctr.c | 438 |
1 files changed, 438 insertions, 0 deletions
diff --git a/crypto/rand/drbg_ctr.c b/crypto/rand/drbg_ctr.c new file mode 100644 index 000000000000..fe15164451e8 --- /dev/null +++ b/crypto/rand/drbg_ctr.c @@ -0,0 +1,438 @@ +/* + * 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; +} |