--- /dev/null
+/* 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;
+};
+
+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;
+ 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 = OPENSSL_malloc(sizeof(struct aead_aes_ctr_hmac_sha256_ctx));
+ if (aes_ctx == NULL) {
+ OPENSSL_PUT_ERROR(CIPHER, ERR_R_MALLOC_FAILURE);
+ 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);
+
+ ctx->aead_state = aes_ctx;
+
+ return 1;
+}
+
+static void aead_aes_ctr_hmac_sha256_cleanup(EVP_AEAD_CTX *ctx) {
+ OPENSSL_free(ctx->aead_state);
+}
+
+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 = ctx->aead_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 = ctx->aead_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;
+}
git://repos.xcallymotion.com / motion2.git / blobdiff