ref: 2bbc75bddc6f2a07056ff017108e35f14061041b
dir: /third_party/boringssl/src/crypto/cipher_extra/e_aesctrhmac.c/
/* Copyright (c) 2017, Google Inc.
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
#include <openssl/aead.h>
#include <openssl/cipher.h>
#include <openssl/crypto.h>
#include <openssl/err.h>
#include <openssl/sha.h>
#include "../fipsmodule/cipher/internal.h"
#define EVP_AEAD_AES_CTR_HMAC_SHA256_TAG_LEN SHA256_DIGEST_LENGTH
#define EVP_AEAD_AES_CTR_HMAC_SHA256_NONCE_LEN 12
struct aead_aes_ctr_hmac_sha256_ctx {
union {
double align;
AES_KEY ks;
} ks;
ctr128_f ctr;
block128_f block;
SHA256_CTX inner_init_state;
SHA256_CTX outer_init_state;
};
OPENSSL_STATIC_ASSERT(sizeof(((EVP_AEAD_CTX *)NULL)->state) >=
sizeof(struct aead_aes_ctr_hmac_sha256_ctx),
"AEAD state is too small");
#if defined(__GNUC__) || defined(__clang__)
OPENSSL_STATIC_ASSERT(alignof(union evp_aead_ctx_st_state) >=
alignof(struct aead_aes_ctr_hmac_sha256_ctx),
"AEAD state has insufficient alignment");
#endif
static void hmac_init(SHA256_CTX *out_inner, SHA256_CTX *out_outer,
const uint8_t hmac_key[32]) {
static const size_t hmac_key_len = 32;
uint8_t block[SHA256_CBLOCK];
OPENSSL_memcpy(block, hmac_key, hmac_key_len);
OPENSSL_memset(block + hmac_key_len, 0x36, sizeof(block) - hmac_key_len);
unsigned i;
for (i = 0; i < hmac_key_len; i++) {
block[i] ^= 0x36;
}
SHA256_Init(out_inner);
SHA256_Update(out_inner, block, sizeof(block));
OPENSSL_memset(block + hmac_key_len, 0x5c, sizeof(block) - hmac_key_len);
for (i = 0; i < hmac_key_len; i++) {
block[i] ^= (0x36 ^ 0x5c);
}
SHA256_Init(out_outer);
SHA256_Update(out_outer, block, sizeof(block));
}
static int aead_aes_ctr_hmac_sha256_init(EVP_AEAD_CTX *ctx, const uint8_t *key,
size_t key_len, size_t tag_len) {
struct aead_aes_ctr_hmac_sha256_ctx *aes_ctx =
(struct aead_aes_ctr_hmac_sha256_ctx *)&ctx->state;
static const size_t hmac_key_len = 32;
if (key_len < hmac_key_len) {
OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BAD_KEY_LENGTH);
return 0; // EVP_AEAD_CTX_init should catch this.
}
const size_t aes_key_len = key_len - hmac_key_len;
if (aes_key_len != 16 && aes_key_len != 32) {
OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BAD_KEY_LENGTH);
return 0; // EVP_AEAD_CTX_init should catch this.
}
if (tag_len == EVP_AEAD_DEFAULT_TAG_LENGTH) {
tag_len = EVP_AEAD_AES_CTR_HMAC_SHA256_TAG_LEN;
}
if (tag_len > EVP_AEAD_AES_CTR_HMAC_SHA256_TAG_LEN) {
OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_TAG_TOO_LARGE);
return 0;
}
aes_ctx->ctr =
aes_ctr_set_key(&aes_ctx->ks.ks, NULL, &aes_ctx->block, key, aes_key_len);
ctx->tag_len = tag_len;
hmac_init(&aes_ctx->inner_init_state, &aes_ctx->outer_init_state,
key + aes_key_len);
return 1;
}
static void aead_aes_ctr_hmac_sha256_cleanup(EVP_AEAD_CTX *ctx) {}
static void hmac_update_uint64(SHA256_CTX *sha256, uint64_t value) {
unsigned i;
uint8_t bytes[8];
for (i = 0; i < sizeof(bytes); i++) {
bytes[i] = value & 0xff;
value >>= 8;
}
SHA256_Update(sha256, bytes, sizeof(bytes));
}
static void hmac_calculate(uint8_t out[SHA256_DIGEST_LENGTH],
const SHA256_CTX *inner_init_state,
const SHA256_CTX *outer_init_state,
const uint8_t *ad, size_t ad_len,
const uint8_t *nonce, const uint8_t *ciphertext,
size_t ciphertext_len) {
SHA256_CTX sha256;
OPENSSL_memcpy(&sha256, inner_init_state, sizeof(sha256));
hmac_update_uint64(&sha256, ad_len);
hmac_update_uint64(&sha256, ciphertext_len);
SHA256_Update(&sha256, nonce, EVP_AEAD_AES_CTR_HMAC_SHA256_NONCE_LEN);
SHA256_Update(&sha256, ad, ad_len);
// Pad with zeros to the end of the SHA-256 block.
const unsigned num_padding =
(SHA256_CBLOCK - ((sizeof(uint64_t)*2 +
EVP_AEAD_AES_CTR_HMAC_SHA256_NONCE_LEN + ad_len) %
SHA256_CBLOCK)) %
SHA256_CBLOCK;
uint8_t padding[SHA256_CBLOCK];
OPENSSL_memset(padding, 0, num_padding);
SHA256_Update(&sha256, padding, num_padding);
SHA256_Update(&sha256, ciphertext, ciphertext_len);
uint8_t inner_digest[SHA256_DIGEST_LENGTH];
SHA256_Final(inner_digest, &sha256);
OPENSSL_memcpy(&sha256, outer_init_state, sizeof(sha256));
SHA256_Update(&sha256, inner_digest, sizeof(inner_digest));
SHA256_Final(out, &sha256);
}
static void aead_aes_ctr_hmac_sha256_crypt(
const struct aead_aes_ctr_hmac_sha256_ctx *aes_ctx, uint8_t *out,
const uint8_t *in, size_t len, const uint8_t *nonce) {
// Since the AEAD operation is one-shot, keeping a buffer of unused keystream
// bytes is pointless. However, |CRYPTO_ctr128_encrypt| requires it.
uint8_t partial_block_buffer[AES_BLOCK_SIZE];
unsigned partial_block_offset = 0;
OPENSSL_memset(partial_block_buffer, 0, sizeof(partial_block_buffer));
uint8_t counter[AES_BLOCK_SIZE];
OPENSSL_memcpy(counter, nonce, EVP_AEAD_AES_CTR_HMAC_SHA256_NONCE_LEN);
OPENSSL_memset(counter + EVP_AEAD_AES_CTR_HMAC_SHA256_NONCE_LEN, 0, 4);
if (aes_ctx->ctr) {
CRYPTO_ctr128_encrypt_ctr32(in, out, len, &aes_ctx->ks.ks, counter,
partial_block_buffer, &partial_block_offset,
aes_ctx->ctr);
} else {
CRYPTO_ctr128_encrypt(in, out, len, &aes_ctx->ks.ks, counter,
partial_block_buffer, &partial_block_offset,
aes_ctx->block);
}
}
static int aead_aes_ctr_hmac_sha256_seal_scatter(
const EVP_AEAD_CTX *ctx, uint8_t *out, uint8_t *out_tag,
size_t *out_tag_len, size_t max_out_tag_len, const uint8_t *nonce,
size_t nonce_len, const uint8_t *in, size_t in_len, const uint8_t *extra_in,
size_t extra_in_len, const uint8_t *ad, size_t ad_len) {
const struct aead_aes_ctr_hmac_sha256_ctx *aes_ctx =
(struct aead_aes_ctr_hmac_sha256_ctx *) &ctx->state;
const uint64_t in_len_64 = in_len;
if (in_len_64 >= (UINT64_C(1) << 32) * AES_BLOCK_SIZE) {
// This input is so large it would overflow the 32-bit block counter.
OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_TOO_LARGE);
return 0;
}
if (max_out_tag_len < ctx->tag_len) {
OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BUFFER_TOO_SMALL);
return 0;
}
if (nonce_len != EVP_AEAD_AES_CTR_HMAC_SHA256_NONCE_LEN) {
OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_UNSUPPORTED_NONCE_SIZE);
return 0;
}
aead_aes_ctr_hmac_sha256_crypt(aes_ctx, out, in, in_len, nonce);
uint8_t hmac_result[SHA256_DIGEST_LENGTH];
hmac_calculate(hmac_result, &aes_ctx->inner_init_state,
&aes_ctx->outer_init_state, ad, ad_len, nonce, out, in_len);
OPENSSL_memcpy(out_tag, hmac_result, ctx->tag_len);
*out_tag_len = ctx->tag_len;
return 1;
}
static int aead_aes_ctr_hmac_sha256_open_gather(
const EVP_AEAD_CTX *ctx, uint8_t *out, const uint8_t *nonce,
size_t nonce_len, const uint8_t *in, size_t in_len, const uint8_t *in_tag,
size_t in_tag_len, const uint8_t *ad, size_t ad_len) {
const struct aead_aes_ctr_hmac_sha256_ctx *aes_ctx =
(struct aead_aes_ctr_hmac_sha256_ctx *) &ctx->state;
if (in_tag_len != ctx->tag_len) {
OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BAD_DECRYPT);
return 0;
}
if (nonce_len != EVP_AEAD_AES_CTR_HMAC_SHA256_NONCE_LEN) {
OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_UNSUPPORTED_NONCE_SIZE);
return 0;
}
uint8_t hmac_result[SHA256_DIGEST_LENGTH];
hmac_calculate(hmac_result, &aes_ctx->inner_init_state,
&aes_ctx->outer_init_state, ad, ad_len, nonce, in,
in_len);
if (CRYPTO_memcmp(hmac_result, in_tag, ctx->tag_len) != 0) {
OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BAD_DECRYPT);
return 0;
}
aead_aes_ctr_hmac_sha256_crypt(aes_ctx, out, in, in_len, nonce);
return 1;
}
static const EVP_AEAD aead_aes_128_ctr_hmac_sha256 = {
16 /* AES key */ + 32 /* HMAC key */,
12, // nonce length
EVP_AEAD_AES_CTR_HMAC_SHA256_TAG_LEN, // overhead
EVP_AEAD_AES_CTR_HMAC_SHA256_TAG_LEN, // max tag length
0, // seal_scatter_supports_extra_in
aead_aes_ctr_hmac_sha256_init,
NULL /* init_with_direction */,
aead_aes_ctr_hmac_sha256_cleanup,
NULL /* open */,
aead_aes_ctr_hmac_sha256_seal_scatter,
aead_aes_ctr_hmac_sha256_open_gather,
NULL /* get_iv */,
NULL /* tag_len */,
};
static const EVP_AEAD aead_aes_256_ctr_hmac_sha256 = {
32 /* AES key */ + 32 /* HMAC key */,
12, // nonce length
EVP_AEAD_AES_CTR_HMAC_SHA256_TAG_LEN, // overhead
EVP_AEAD_AES_CTR_HMAC_SHA256_TAG_LEN, // max tag length
0, // seal_scatter_supports_extra_in
aead_aes_ctr_hmac_sha256_init,
NULL /* init_with_direction */,
aead_aes_ctr_hmac_sha256_cleanup,
NULL /* open */,
aead_aes_ctr_hmac_sha256_seal_scatter,
aead_aes_ctr_hmac_sha256_open_gather,
NULL /* get_iv */,
NULL /* tag_len */,
};
const EVP_AEAD *EVP_aead_aes_128_ctr_hmac_sha256(void) {
return &aead_aes_128_ctr_hmac_sha256;
}
const EVP_AEAD *EVP_aead_aes_256_ctr_hmac_sha256(void) {
return &aead_aes_256_ctr_hmac_sha256;
}