| /* 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/cpu.h> |
| #include <openssl/crypto.h> |
| #include <openssl/err.h> |
| |
| #include "../fipsmodule/cipher/internal.h" |
| |
| |
| #if !defined(OPENSSL_SMALL) |
| |
| #define EVP_AEAD_AES_GCM_SIV_NONCE_LEN 12 |
| #define EVP_AEAD_AES_GCM_SIV_TAG_LEN 16 |
| |
| #if defined(OPENSSL_X86_64) && !defined(OPENSSL_NO_ASM) |
| |
| /* Optimised AES-GCM-SIV */ |
| |
| struct aead_aes_gcm_siv_asm_ctx { |
| alignas(64) uint8_t key[16*15]; |
| int is_128_bit; |
| }; |
| |
| /* aes128gcmsiv_aes_ks writes an AES-128 key schedule for |key| to |
| * |out_expanded_key|. */ |
| extern void aes128gcmsiv_aes_ks( |
| const uint8_t key[16], uint8_t out_expanded_key[16*15]); |
| |
| /* aes128gcmsiv_aes_ks writes an AES-128 key schedule for |key| to |
| * |out_expanded_key|. */ |
| extern void aes256gcmsiv_aes_ks( |
| const uint8_t key[16], uint8_t out_expanded_key[16*15]); |
| |
| static int aead_aes_gcm_siv_asm_init(EVP_AEAD_CTX *ctx, const uint8_t *key, |
| size_t key_len, size_t tag_len) { |
| const size_t key_bits = key_len * 8; |
| |
| if (key_bits != 128 && key_bits != 256) { |
| 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_GCM_SIV_TAG_LEN; |
| } |
| |
| if (tag_len != EVP_AEAD_AES_GCM_SIV_TAG_LEN) { |
| OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_TAG_TOO_LARGE); |
| return 0; |
| } |
| |
| struct aead_aes_gcm_siv_asm_ctx *gcm_siv_ctx = |
| OPENSSL_malloc(sizeof(struct aead_aes_gcm_siv_asm_ctx)); |
| if (gcm_siv_ctx == NULL) { |
| return 0; |
| } |
| |
| if (key_bits == 128) { |
| aes128gcmsiv_aes_ks(key, &gcm_siv_ctx->key[0]); |
| gcm_siv_ctx->is_128_bit = 1; |
| } else { |
| aes256gcmsiv_aes_ks(key, &gcm_siv_ctx->key[0]); |
| gcm_siv_ctx->is_128_bit = 0; |
| } |
| ctx->aead_state = gcm_siv_ctx; |
| |
| return 1; |
| } |
| |
| static void aead_aes_gcm_siv_asm_cleanup(EVP_AEAD_CTX *ctx) { |
| struct aead_aes_gcm_siv_asm_ctx *gcm_siv_asm_ctx = ctx->aead_state; |
| OPENSSL_cleanse(gcm_siv_asm_ctx, sizeof(struct aead_aes_gcm_siv_asm_ctx)); |
| OPENSSL_free(gcm_siv_asm_ctx); |
| } |
| |
| /* aesgcmsiv_polyval_horner updates the POLYVAL value in |in_out_poly| to |
| * include a number (|in_blocks|) of 16-byte blocks of data from |in|, given |
| * the POLYVAL key in |key|. */ |
| extern void aesgcmsiv_polyval_horner(const uint8_t in_out_poly[16], |
| const uint8_t key[16], const uint8_t *in, |
| size_t in_blocks); |
| |
| /* aesgcmsiv_htable_init writes powers 1..8 of |auth_key| to |out_htable|. */ |
| extern void aesgcmsiv_htable_init(uint8_t out_htable[16 * 8], |
| const uint8_t auth_key[16]); |
| |
| /* aesgcmsiv_htable6_init writes powers 1..6 of |auth_key| to |out_htable|. */ |
| extern void aesgcmsiv_htable6_init(uint8_t out_htable[16 * 6], |
| const uint8_t auth_key[16]); |
| |
| /* aesgcmsiv_htable_polyval updates the POLYVAL value in |in_out_poly| to |
| * include |in_len| bytes of data from |in|. (Where |in_len| must be a multiple |
| * of 16.) It uses the precomputed powers of the key given in |htable|. */ |
| extern void aesgcmsiv_htable_polyval(const uint8_t htable[16 * 8], |
| const uint8_t *in, size_t in_len, |
| uint8_t in_out_poly[16]); |
| |
| /* aes128gcmsiv_dec decrypts |in_len| & ~15 bytes from |out| and writes them to |
| * |in|. (The full value of |in_len| is still used to find the authentication |
| * tag appended to the ciphertext, however, so must not be pre-masked.) |
| * |
| * |in| and |out| may be equal, but must not otherwise overlap. |
| * |
| * While decrypting, it updates the POLYVAL value found at the beginning of |
| * |in_out_calculated_tag_and_scratch| and writes the updated value back before |
| * return. During executation, it may use the whole of this space for other |
| * purposes. In order to decrypt and update the POLYVAL value, it uses the |
| * expanded key from |key| and the table of powers in |htable|. */ |
| extern void aes128gcmsiv_dec(const uint8_t *in, uint8_t *out, |
| uint8_t in_out_calculated_tag_and_scratch[16 * 8], |
| const uint8_t htable[16 * 6], |
| const struct aead_aes_gcm_siv_asm_ctx *key, |
| size_t in_len); |
| |
| /* aes256gcmsiv_dec acts like |aes128gcmsiv_dec|, but for AES-256. */ |
| extern void aes256gcmsiv_dec(const uint8_t *in, uint8_t *out, |
| uint8_t in_out_calculated_tag_and_scratch[16 * 8], |
| const uint8_t htable[16 * 6], |
| const struct aead_aes_gcm_siv_asm_ctx *key, |
| size_t in_len); |
| |
| /* aes128gcmsiv_kdf performs the AES-GCM-SIV KDF given the expanded key from |
| * |key_schedule| and the nonce in |nonce|. Note that, while only 12 bytes of |
| * the nonce are used, 16 bytes are read and so the value must be |
| * right-padded. */ |
| extern void aes128gcmsiv_kdf(const uint8_t nonce[16], |
| uint64_t out_key_material[8], |
| const uint8_t *key_schedule); |
| |
| /* aes256gcmsiv_kdf acts like |aes128gcmsiv_kdf|, but for AES-256. */ |
| extern void aes256gcmsiv_kdf(const uint8_t nonce[16], |
| uint64_t out_key_material[12], |
| const uint8_t *key_schedule); |
| |
| /* aes128gcmsiv_aes_ks_enc_x1 performs a key expansion of the AES-128 key in |
| * |key|, writes the expanded key to |out_expanded_key| and encrypts a single |
| * block from |in| to |out|. */ |
| extern void aes128gcmsiv_aes_ks_enc_x1(const uint8_t in[16], uint8_t out[16], |
| uint8_t out_expanded_key[16 * 15], |
| const uint64_t key[2]); |
| |
| /* aes256gcmsiv_aes_ks_enc_x1 acts like |aes128gcmsiv_aes_ks_enc_x1|, but for |
| * AES-256. */ |
| extern void aes256gcmsiv_aes_ks_enc_x1(const uint8_t in[16], uint8_t out[16], |
| uint8_t out_expanded_key[16 * 15], |
| const uint64_t key[4]); |
| |
| /* aes128gcmsiv_ecb_enc_block encrypts a single block from |in| to |out| using |
| * the expanded key in |expanded_key|. */ |
| extern void aes128gcmsiv_ecb_enc_block( |
| const uint8_t in[16], uint8_t out[16], |
| const struct aead_aes_gcm_siv_asm_ctx *expanded_key); |
| |
| /* aes256gcmsiv_ecb_enc_block acts like |aes128gcmsiv_ecb_enc_block|, but for |
| * AES-256. */ |
| extern void aes256gcmsiv_ecb_enc_block( |
| const uint8_t in[16], uint8_t out[16], |
| const struct aead_aes_gcm_siv_asm_ctx *expanded_key); |
| |
| /* aes128gcmsiv_enc_msg_x4 encrypts |in_len| bytes from |in| to |out| using the |
| * expanded key from |key|. (The value of |in_len| must be a multiple of 16.) |
| * The |in| and |out| buffers may be equal but must not otherwise overlap. The |
| * initial counter is constructed from the given |tag| as required by |
| * AES-GCM-SIV. */ |
| extern void aes128gcmsiv_enc_msg_x4(const uint8_t *in, uint8_t *out, |
| const uint8_t *tag, |
| const struct aead_aes_gcm_siv_asm_ctx *key, |
| size_t in_len); |
| |
| /* aes256gcmsiv_enc_msg_x4 acts like |aes128gcmsiv_enc_msg_x4|, but for |
| * AES-256. */ |
| extern void aes256gcmsiv_enc_msg_x4(const uint8_t *in, uint8_t *out, |
| const uint8_t *tag, |
| const struct aead_aes_gcm_siv_asm_ctx *key, |
| size_t in_len); |
| |
| /* aes128gcmsiv_enc_msg_x8 acts like |aes128gcmsiv_enc_msg_x4|, but is |
| * optimised for longer messages. */ |
| extern void aes128gcmsiv_enc_msg_x8(const uint8_t *in, uint8_t *out, |
| const uint8_t *tag, |
| const struct aead_aes_gcm_siv_asm_ctx *key, |
| size_t in_len); |
| |
| /* aes256gcmsiv_enc_msg_x8 acts like |aes256gcmsiv_enc_msg_x4|, but is |
| * optimised for longer messages. */ |
| extern void aes256gcmsiv_enc_msg_x8(const uint8_t *in, uint8_t *out, |
| const uint8_t *tag, |
| const struct aead_aes_gcm_siv_asm_ctx *key, |
| size_t in_len); |
| |
| /* gcm_siv_asm_polyval evaluates POLYVAL at |auth_key| on the given plaintext |
| * and AD. The result is written to |out_tag|. */ |
| static void gcm_siv_asm_polyval(uint8_t out_tag[16], const uint8_t *in, |
| size_t in_len, const uint8_t *ad, size_t ad_len, |
| const uint8_t auth_key[16], |
| const uint8_t nonce[12]) { |
| OPENSSL_memset(out_tag, 0, 16); |
| const size_t ad_blocks = ad_len / 16; |
| const size_t in_blocks = in_len / 16; |
| int htable_init = 0; |
| alignas(16) uint8_t htable[16*8]; |
| |
| if (ad_blocks > 8 || in_blocks > 8) { |
| htable_init = 1; |
| aesgcmsiv_htable_init(htable, auth_key); |
| } |
| |
| if (htable_init) { |
| aesgcmsiv_htable_polyval(htable, ad, ad_len & ~15, out_tag); |
| } else { |
| aesgcmsiv_polyval_horner(out_tag, auth_key, ad, ad_blocks); |
| } |
| |
| uint8_t scratch[16]; |
| if (ad_len & 15) { |
| OPENSSL_memset(scratch, 0, sizeof(scratch)); |
| OPENSSL_memcpy(scratch, &ad[ad_len & ~15], ad_len & 15); |
| aesgcmsiv_polyval_horner(out_tag, auth_key, scratch, 1); |
| } |
| |
| if (htable_init) { |
| aesgcmsiv_htable_polyval(htable, in, in_len & ~15, out_tag); |
| } else { |
| aesgcmsiv_polyval_horner(out_tag, auth_key, in, in_blocks); |
| } |
| |
| if (in_len & 15) { |
| OPENSSL_memset(scratch, 0, sizeof(scratch)); |
| OPENSSL_memcpy(scratch, &in[in_len & ~15], in_len & 15); |
| aesgcmsiv_polyval_horner(out_tag, auth_key, scratch, 1); |
| } |
| |
| union { |
| uint8_t c[16]; |
| struct { |
| uint64_t ad; |
| uint64_t in; |
| } bitlens; |
| } length_block; |
| |
| length_block.bitlens.ad = ad_len * 8; |
| length_block.bitlens.in = in_len * 8; |
| aesgcmsiv_polyval_horner(out_tag, auth_key, length_block.c, 1); |
| |
| for (size_t i = 0; i < 12; i++) { |
| out_tag[i] ^= nonce[i]; |
| } |
| |
| out_tag[15] &= 0x7f; |
| } |
| |
| /* aead_aes_gcm_siv_asm_crypt_last_block handles the encryption/decryption |
| * (same thing in CTR mode) of the final block of a plaintext/ciphertext. It |
| * writes |in_len| & 15 bytes to |out| + |in_len|, based on an initial counter |
| * derived from |tag|. */ |
| static void aead_aes_gcm_siv_asm_crypt_last_block( |
| int is_128_bit, uint8_t *out, const uint8_t *in, size_t in_len, |
| const uint8_t tag[16], |
| const struct aead_aes_gcm_siv_asm_ctx *enc_key_expanded) { |
| alignas(16) union { |
| uint8_t c[16]; |
| uint32_t u32[4]; |
| } counter; |
| OPENSSL_memcpy(&counter, tag, sizeof(counter)); |
| counter.c[15] |= 0x80; |
| counter.u32[0] += in_len / 16; |
| |
| if (is_128_bit) { |
| aes128gcmsiv_ecb_enc_block(&counter.c[0], &counter.c[0], enc_key_expanded); |
| } else { |
| aes256gcmsiv_ecb_enc_block(&counter.c[0], &counter.c[0], enc_key_expanded); |
| } |
| |
| const size_t last_bytes_offset = in_len & ~15; |
| const size_t last_bytes_len = in_len & 15; |
| uint8_t *last_bytes_out = &out[last_bytes_offset]; |
| const uint8_t *last_bytes_in = &in[last_bytes_offset]; |
| for (size_t i = 0; i < last_bytes_len; i++) { |
| last_bytes_out[i] = last_bytes_in[i] ^ counter.c[i]; |
| } |
| } |
| |
| /* aead_aes_gcm_siv_kdf calculates the record encryption and authentication |
| * keys given the |nonce|. */ |
| static void aead_aes_gcm_siv_kdf( |
| int is_128_bit, const struct aead_aes_gcm_siv_asm_ctx *gcm_siv_ctx, |
| uint64_t out_record_auth_key[2], uint64_t out_record_enc_key[4], |
| const uint8_t nonce[12]) { |
| alignas(16) uint8_t padded_nonce[16]; |
| OPENSSL_memcpy(padded_nonce, nonce, 12); |
| |
| alignas(16) uint64_t key_material[12]; |
| if (is_128_bit) { |
| aes128gcmsiv_kdf(padded_nonce, key_material, &gcm_siv_ctx->key[0]); |
| out_record_enc_key[0] = key_material[4]; |
| out_record_enc_key[1] = key_material[6]; |
| } else { |
| aes256gcmsiv_kdf(padded_nonce, key_material, &gcm_siv_ctx->key[0]); |
| out_record_enc_key[0] = key_material[4]; |
| out_record_enc_key[1] = key_material[6]; |
| out_record_enc_key[2] = key_material[8]; |
| out_record_enc_key[3] = key_material[10]; |
| } |
| |
| out_record_auth_key[0] = key_material[0]; |
| out_record_auth_key[1] = key_material[2]; |
| } |
| |
| static int aead_aes_gcm_siv_asm_seal(const EVP_AEAD_CTX *ctx, uint8_t *out, |
| size_t *out_len, size_t max_out_len, |
| const uint8_t *nonce, size_t nonce_len, |
| const uint8_t *in, size_t in_len, |
| const uint8_t *ad, size_t ad_len) { |
| const struct aead_aes_gcm_siv_asm_ctx *gcm_siv_ctx = ctx->aead_state; |
| const uint64_t in_len_64 = in_len; |
| const uint64_t ad_len_64 = ad_len; |
| |
| if (in_len + EVP_AEAD_AES_GCM_SIV_TAG_LEN < in_len || |
| in_len_64 > (UINT64_C(1) << 36) || |
| ad_len_64 >= (UINT64_C(1) << 61)) { |
| OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_TOO_LARGE); |
| return 0; |
| } |
| |
| if (max_out_len < in_len + EVP_AEAD_AES_GCM_SIV_TAG_LEN) { |
| OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BUFFER_TOO_SMALL); |
| return 0; |
| } |
| |
| if (nonce_len != EVP_AEAD_AES_GCM_SIV_NONCE_LEN) { |
| OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_UNSUPPORTED_NONCE_SIZE); |
| return 0; |
| } |
| |
| alignas(16) uint64_t record_auth_key[2]; |
| alignas(16) uint64_t record_enc_key[4]; |
| aead_aes_gcm_siv_kdf(gcm_siv_ctx->is_128_bit, gcm_siv_ctx, record_auth_key, |
| record_enc_key, nonce); |
| |
| alignas(16) uint8_t tag[16] = {0}; |
| gcm_siv_asm_polyval(tag, in, in_len, ad, ad_len, |
| (const uint8_t *)record_auth_key, nonce); |
| |
| struct aead_aes_gcm_siv_asm_ctx enc_key_expanded; |
| |
| if (gcm_siv_ctx->is_128_bit) { |
| aes128gcmsiv_aes_ks_enc_x1(tag, tag, &enc_key_expanded.key[0], |
| record_enc_key); |
| |
| if (in_len < 128) { |
| aes128gcmsiv_enc_msg_x4(in, out, tag, &enc_key_expanded, in_len & ~15); |
| } else { |
| aes128gcmsiv_enc_msg_x8(in, out, tag, &enc_key_expanded, in_len & ~15); |
| } |
| } else { |
| aes256gcmsiv_aes_ks_enc_x1(tag, tag, &enc_key_expanded.key[0], |
| record_enc_key); |
| |
| if (in_len < 128) { |
| aes256gcmsiv_enc_msg_x4(in, out, tag, &enc_key_expanded, in_len & ~15); |
| } else { |
| aes256gcmsiv_enc_msg_x8(in, out, tag, &enc_key_expanded, in_len & ~15); |
| } |
| } |
| |
| if (in_len & 15) { |
| aead_aes_gcm_siv_asm_crypt_last_block(gcm_siv_ctx->is_128_bit, out, in, |
| in_len, tag, &enc_key_expanded); |
| } |
| |
| OPENSSL_memcpy(out + in_len, tag, sizeof(tag)); |
| *out_len = in_len + EVP_AEAD_AES_GCM_SIV_TAG_LEN; |
| |
| return 1; |
| } |
| |
| static int aead_aes_gcm_siv_asm_open(const EVP_AEAD_CTX *ctx, uint8_t *out, |
| size_t *out_len, size_t max_out_len, |
| const uint8_t *nonce, size_t nonce_len, |
| const uint8_t *in, size_t in_len, |
| const uint8_t *ad, size_t ad_len) { |
| const uint64_t ad_len_64 = ad_len; |
| if (ad_len_64 >= (UINT64_C(1) << 61)) { |
| OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_TOO_LARGE); |
| return 0; |
| } |
| |
| const uint64_t in_len_64 = in_len; |
| if (in_len < EVP_AEAD_AES_GCM_SIV_TAG_LEN || |
| in_len_64 > (UINT64_C(1) << 36) + AES_BLOCK_SIZE) { |
| OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BAD_DECRYPT); |
| return 0; |
| } |
| |
| const struct aead_aes_gcm_siv_asm_ctx *gcm_siv_ctx = ctx->aead_state; |
| const size_t plaintext_len = in_len - EVP_AEAD_AES_GCM_SIV_TAG_LEN; |
| const uint8_t *const given_tag = in + plaintext_len; |
| |
| if (max_out_len < plaintext_len) { |
| OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BUFFER_TOO_SMALL); |
| return 0; |
| } |
| |
| alignas(16) uint64_t record_auth_key[2]; |
| alignas(16) uint64_t record_enc_key[4]; |
| aead_aes_gcm_siv_kdf(gcm_siv_ctx->is_128_bit, gcm_siv_ctx, record_auth_key, |
| record_enc_key, nonce); |
| |
| struct aead_aes_gcm_siv_asm_ctx expanded_key; |
| if (gcm_siv_ctx->is_128_bit) { |
| aes128gcmsiv_aes_ks((const uint8_t *) record_enc_key, &expanded_key.key[0]); |
| } else { |
| aes256gcmsiv_aes_ks((const uint8_t *) record_enc_key, &expanded_key.key[0]); |
| } |
| /* calculated_tag is 16*8 bytes, rather than 16 bytes, because |
| * aes[128|256]gcmsiv_dec uses the extra as scratch space. */ |
| alignas(16) uint8_t calculated_tag[16 * 8] = {0}; |
| |
| OPENSSL_memset(calculated_tag, 0, EVP_AEAD_AES_GCM_SIV_TAG_LEN); |
| const size_t ad_blocks = ad_len / 16; |
| aesgcmsiv_polyval_horner(calculated_tag, (const uint8_t *)record_auth_key, ad, |
| ad_blocks); |
| |
| uint8_t scratch[16]; |
| if (ad_len & 15) { |
| OPENSSL_memset(scratch, 0, sizeof(scratch)); |
| OPENSSL_memcpy(scratch, &ad[ad_len & ~15], ad_len & 15); |
| aesgcmsiv_polyval_horner(calculated_tag, (const uint8_t *)record_auth_key, |
| scratch, 1); |
| } |
| |
| alignas(16) uint8_t htable[16 * 6]; |
| aesgcmsiv_htable6_init(htable, (const uint8_t *)record_auth_key); |
| |
| if (gcm_siv_ctx->is_128_bit) { |
| aes128gcmsiv_dec(in, out, calculated_tag, htable, &expanded_key, |
| plaintext_len); |
| } else { |
| aes256gcmsiv_dec(in, out, calculated_tag, htable, &expanded_key, |
| plaintext_len); |
| } |
| |
| if (plaintext_len & 15) { |
| aead_aes_gcm_siv_asm_crypt_last_block(gcm_siv_ctx->is_128_bit, out, in, |
| plaintext_len, given_tag, |
| &expanded_key); |
| OPENSSL_memset(scratch, 0, sizeof(scratch)); |
| OPENSSL_memcpy(scratch, out + (plaintext_len & ~15), plaintext_len & 15); |
| aesgcmsiv_polyval_horner(calculated_tag, (const uint8_t *)record_auth_key, |
| scratch, 1); |
| } |
| |
| union { |
| uint8_t c[16]; |
| struct { |
| uint64_t ad; |
| uint64_t in; |
| } bitlens; |
| } length_block; |
| |
| length_block.bitlens.ad = ad_len * 8; |
| length_block.bitlens.in = plaintext_len * 8; |
| aesgcmsiv_polyval_horner(calculated_tag, (const uint8_t *)record_auth_key, |
| length_block.c, 1); |
| |
| for (size_t i = 0; i < 12; i++) { |
| calculated_tag[i] ^= nonce[i]; |
| } |
| |
| calculated_tag[15] &= 0x7f; |
| |
| if (gcm_siv_ctx->is_128_bit) { |
| aes128gcmsiv_ecb_enc_block(calculated_tag, calculated_tag, &expanded_key); |
| } else { |
| aes256gcmsiv_ecb_enc_block(calculated_tag, calculated_tag, &expanded_key); |
| } |
| |
| if (CRYPTO_memcmp(calculated_tag, given_tag, EVP_AEAD_AES_GCM_SIV_TAG_LEN) != |
| 0) { |
| OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BAD_DECRYPT); |
| return 0; |
| } |
| |
| *out_len = in_len - EVP_AEAD_AES_GCM_SIV_TAG_LEN; |
| return 1; |
| } |
| |
| static const EVP_AEAD aead_aes_128_gcm_siv_asm = { |
| 16, /* key length */ |
| EVP_AEAD_AES_GCM_SIV_NONCE_LEN, /* nonce length */ |
| EVP_AEAD_AES_GCM_SIV_TAG_LEN, /* overhead */ |
| EVP_AEAD_AES_GCM_SIV_TAG_LEN, /* max tag length */ |
| |
| aead_aes_gcm_siv_asm_init, |
| NULL /* init_with_direction */, |
| aead_aes_gcm_siv_asm_cleanup, |
| aead_aes_gcm_siv_asm_seal, |
| aead_aes_gcm_siv_asm_open, |
| NULL /* get_iv */, |
| }; |
| |
| static const EVP_AEAD aead_aes_256_gcm_siv_asm = { |
| 32, /* key length */ |
| EVP_AEAD_AES_GCM_SIV_NONCE_LEN, /* nonce length */ |
| EVP_AEAD_AES_GCM_SIV_TAG_LEN, /* overhead */ |
| EVP_AEAD_AES_GCM_SIV_TAG_LEN, /* max tag length */ |
| |
| aead_aes_gcm_siv_asm_init, |
| NULL /* init_with_direction */, |
| aead_aes_gcm_siv_asm_cleanup, |
| aead_aes_gcm_siv_asm_seal, |
| aead_aes_gcm_siv_asm_open, |
| NULL /* get_iv */, |
| }; |
| |
| #endif /* X86_64 && !NO_ASM */ |
| |
| struct aead_aes_gcm_siv_ctx { |
| union { |
| double align; |
| AES_KEY ks; |
| } ks; |
| block128_f kgk_block; |
| unsigned is_256:1; |
| }; |
| |
| static int aead_aes_gcm_siv_init(EVP_AEAD_CTX *ctx, const uint8_t *key, |
| size_t key_len, size_t tag_len) { |
| const size_t key_bits = key_len * 8; |
| |
| if (key_bits != 128 && key_bits != 256) { |
| 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_GCM_SIV_TAG_LEN; |
| } |
| |
| if (tag_len != EVP_AEAD_AES_GCM_SIV_TAG_LEN) { |
| OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_TAG_TOO_LARGE); |
| return 0; |
| } |
| |
| struct aead_aes_gcm_siv_ctx *gcm_siv_ctx = |
| OPENSSL_malloc(sizeof(struct aead_aes_gcm_siv_ctx)); |
| if (gcm_siv_ctx == NULL) { |
| return 0; |
| } |
| OPENSSL_memset(gcm_siv_ctx, 0, sizeof(struct aead_aes_gcm_siv_ctx)); |
| |
| aes_ctr_set_key(&gcm_siv_ctx->ks.ks, NULL, &gcm_siv_ctx->kgk_block, key, |
| key_len); |
| gcm_siv_ctx->is_256 = (key_len == 32); |
| ctx->aead_state = gcm_siv_ctx; |
| |
| return 1; |
| } |
| |
| static void aead_aes_gcm_siv_cleanup(EVP_AEAD_CTX *ctx) { |
| struct aead_aes_gcm_siv_ctx *gcm_siv_ctx = ctx->aead_state; |
| OPENSSL_cleanse(gcm_siv_ctx, sizeof(struct aead_aes_gcm_siv_ctx)); |
| OPENSSL_free(gcm_siv_ctx); |
| } |
| |
| /* gcm_siv_crypt encrypts (or decrypts—it's the same thing) |in_len| bytes from |
| * |in| to |out|, using the block function |enc_block| with |key| in counter |
| * mode, starting at |initial_counter|. This differs from the traditional |
| * counter mode code in that the counter is handled little-endian, only the |
| * first four bytes are used and the GCM-SIV tweak to the final byte is |
| * applied. The |in| and |out| pointers may be equal but otherwise must not |
| * alias. */ |
| static void gcm_siv_crypt(uint8_t *out, const uint8_t *in, size_t in_len, |
| const uint8_t initial_counter[AES_BLOCK_SIZE], |
| block128_f enc_block, const AES_KEY *key) { |
| union { |
| uint32_t w[4]; |
| uint8_t c[16]; |
| } counter; |
| |
| OPENSSL_memcpy(counter.c, initial_counter, AES_BLOCK_SIZE); |
| counter.c[15] |= 0x80; |
| |
| for (size_t done = 0; done < in_len;) { |
| uint8_t keystream[AES_BLOCK_SIZE]; |
| enc_block(counter.c, keystream, key); |
| counter.w[0]++; |
| |
| size_t todo = AES_BLOCK_SIZE; |
| if (in_len - done < todo) { |
| todo = in_len - done; |
| } |
| |
| for (size_t i = 0; i < todo; i++) { |
| out[done + i] = keystream[i] ^ in[done + i]; |
| } |
| |
| done += todo; |
| } |
| } |
| |
| /* gcm_siv_polyval evaluates POLYVAL at |auth_key| on the given plaintext and |
| * AD. The result is written to |out_tag|. */ |
| static void gcm_siv_polyval( |
| uint8_t out_tag[16], const uint8_t *in, size_t in_len, const uint8_t *ad, |
| size_t ad_len, const uint8_t auth_key[16], |
| const uint8_t nonce[EVP_AEAD_AES_GCM_SIV_NONCE_LEN]) { |
| struct polyval_ctx polyval_ctx; |
| CRYPTO_POLYVAL_init(&polyval_ctx, auth_key); |
| |
| CRYPTO_POLYVAL_update_blocks(&polyval_ctx, ad, ad_len & ~15); |
| |
| uint8_t scratch[16]; |
| if (ad_len & 15) { |
| OPENSSL_memset(scratch, 0, sizeof(scratch)); |
| OPENSSL_memcpy(scratch, &ad[ad_len & ~15], ad_len & 15); |
| CRYPTO_POLYVAL_update_blocks(&polyval_ctx, scratch, sizeof(scratch)); |
| } |
| |
| CRYPTO_POLYVAL_update_blocks(&polyval_ctx, in, in_len & ~15); |
| if (in_len & 15) { |
| OPENSSL_memset(scratch, 0, sizeof(scratch)); |
| OPENSSL_memcpy(scratch, &in[in_len & ~15], in_len & 15); |
| CRYPTO_POLYVAL_update_blocks(&polyval_ctx, scratch, sizeof(scratch)); |
| } |
| |
| union { |
| uint8_t c[16]; |
| struct { |
| uint64_t ad; |
| uint64_t in; |
| } bitlens; |
| } length_block; |
| |
| length_block.bitlens.ad = ad_len * 8; |
| length_block.bitlens.in = in_len * 8; |
| CRYPTO_POLYVAL_update_blocks(&polyval_ctx, length_block.c, |
| sizeof(length_block)); |
| |
| CRYPTO_POLYVAL_finish(&polyval_ctx, out_tag); |
| for (size_t i = 0; i < EVP_AEAD_AES_GCM_SIV_NONCE_LEN; i++) { |
| out_tag[i] ^= nonce[i]; |
| } |
| out_tag[15] &= 0x7f; |
| } |
| |
| /* gcm_siv_record_keys contains the keys used for a specific GCM-SIV record. */ |
| struct gcm_siv_record_keys { |
| uint8_t auth_key[16]; |
| union { |
| double align; |
| AES_KEY ks; |
| } enc_key; |
| block128_f enc_block; |
| }; |
| |
| /* gcm_siv_keys calculates the keys for a specific GCM-SIV record with the |
| * given nonce and writes them to |*out_keys|. */ |
| static void gcm_siv_keys( |
| const struct aead_aes_gcm_siv_ctx *gcm_siv_ctx, |
| struct gcm_siv_record_keys *out_keys, |
| const uint8_t nonce[EVP_AEAD_AES_GCM_SIV_NONCE_LEN]) { |
| const AES_KEY *const key = &gcm_siv_ctx->ks.ks; |
| uint8_t key_material[(128 /* POLYVAL key */ + 256 /* max AES key */) / 8]; |
| const size_t blocks_needed = gcm_siv_ctx->is_256 ? 6 : 4; |
| |
| uint8_t counter[AES_BLOCK_SIZE]; |
| OPENSSL_memset(counter, 0, AES_BLOCK_SIZE - EVP_AEAD_AES_GCM_SIV_NONCE_LEN); |
| OPENSSL_memcpy(counter + AES_BLOCK_SIZE - EVP_AEAD_AES_GCM_SIV_NONCE_LEN, |
| nonce, EVP_AEAD_AES_GCM_SIV_NONCE_LEN); |
| for (size_t i = 0; i < blocks_needed; i++) { |
| counter[0] = i; |
| |
| uint8_t ciphertext[AES_BLOCK_SIZE]; |
| gcm_siv_ctx->kgk_block(counter, ciphertext, key); |
| OPENSSL_memcpy(&key_material[i * 8], ciphertext, 8); |
| } |
| |
| OPENSSL_memcpy(out_keys->auth_key, key_material, 16); |
| aes_ctr_set_key(&out_keys->enc_key.ks, NULL, &out_keys->enc_block, |
| key_material + 16, gcm_siv_ctx->is_256 ? 32 : 16); |
| } |
| |
| static int aead_aes_gcm_siv_seal(const EVP_AEAD_CTX *ctx, uint8_t *out, |
| size_t *out_len, size_t max_out_len, |
| const uint8_t *nonce, size_t nonce_len, |
| const uint8_t *in, size_t in_len, |
| const uint8_t *ad, size_t ad_len) { |
| const struct aead_aes_gcm_siv_ctx *gcm_siv_ctx = ctx->aead_state; |
| const uint64_t in_len_64 = in_len; |
| const uint64_t ad_len_64 = ad_len; |
| |
| if (in_len + EVP_AEAD_AES_GCM_SIV_TAG_LEN < in_len || |
| in_len_64 > (UINT64_C(1) << 36) || |
| ad_len_64 >= (UINT64_C(1) << 61)) { |
| OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_TOO_LARGE); |
| return 0; |
| } |
| |
| if (max_out_len < in_len + EVP_AEAD_AES_GCM_SIV_TAG_LEN) { |
| OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BUFFER_TOO_SMALL); |
| return 0; |
| } |
| |
| if (nonce_len != EVP_AEAD_AES_GCM_SIV_NONCE_LEN) { |
| OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_UNSUPPORTED_NONCE_SIZE); |
| return 0; |
| } |
| |
| struct gcm_siv_record_keys keys; |
| gcm_siv_keys(gcm_siv_ctx, &keys, nonce); |
| |
| uint8_t tag[16]; |
| gcm_siv_polyval(tag, in, in_len, ad, ad_len, keys.auth_key, nonce); |
| keys.enc_block(tag, tag, &keys.enc_key.ks); |
| |
| gcm_siv_crypt(out, in, in_len, tag, keys.enc_block, &keys.enc_key.ks); |
| |
| OPENSSL_memcpy(&out[in_len], tag, EVP_AEAD_AES_GCM_SIV_TAG_LEN); |
| *out_len = in_len + EVP_AEAD_AES_GCM_SIV_TAG_LEN; |
| |
| return 1; |
| } |
| |
| static int aead_aes_gcm_siv_open(const EVP_AEAD_CTX *ctx, uint8_t *out, |
| size_t *out_len, size_t max_out_len, |
| const uint8_t *nonce, size_t nonce_len, |
| const uint8_t *in, size_t in_len, |
| const uint8_t *ad, size_t ad_len) { |
| const uint64_t ad_len_64 = ad_len; |
| if (ad_len_64 >= (UINT64_C(1) << 61)) { |
| OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_TOO_LARGE); |
| return 0; |
| } |
| |
| const uint64_t in_len_64 = in_len; |
| if (in_len < EVP_AEAD_AES_GCM_SIV_TAG_LEN || |
| in_len_64 > (UINT64_C(1) << 36) + AES_BLOCK_SIZE) { |
| OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BAD_DECRYPT); |
| return 0; |
| } |
| |
| if (nonce_len != EVP_AEAD_AES_GCM_SIV_NONCE_LEN) { |
| OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_UNSUPPORTED_NONCE_SIZE); |
| return 0; |
| } |
| |
| const struct aead_aes_gcm_siv_ctx *gcm_siv_ctx = ctx->aead_state; |
| const size_t plaintext_len = in_len - EVP_AEAD_AES_GCM_SIV_TAG_LEN; |
| |
| if (max_out_len < plaintext_len) { |
| OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BUFFER_TOO_SMALL); |
| return 0; |
| } |
| |
| struct gcm_siv_record_keys keys; |
| gcm_siv_keys(gcm_siv_ctx, &keys, nonce); |
| |
| gcm_siv_crypt(out, in, plaintext_len, &in[plaintext_len], keys.enc_block, |
| &keys.enc_key.ks); |
| |
| uint8_t expected_tag[EVP_AEAD_AES_GCM_SIV_TAG_LEN]; |
| gcm_siv_polyval(expected_tag, out, plaintext_len, ad, ad_len, keys.auth_key, |
| nonce); |
| keys.enc_block(expected_tag, expected_tag, &keys.enc_key.ks); |
| |
| if (CRYPTO_memcmp(expected_tag, &in[plaintext_len], sizeof(expected_tag)) != |
| 0) { |
| OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BAD_DECRYPT); |
| return 0; |
| } |
| |
| *out_len = plaintext_len; |
| return 1; |
| } |
| |
| static const EVP_AEAD aead_aes_128_gcm_siv = { |
| 16, /* key length */ |
| EVP_AEAD_AES_GCM_SIV_NONCE_LEN, /* nonce length */ |
| EVP_AEAD_AES_GCM_SIV_TAG_LEN, /* overhead */ |
| EVP_AEAD_AES_GCM_SIV_TAG_LEN, /* max tag length */ |
| |
| aead_aes_gcm_siv_init, |
| NULL /* init_with_direction */, |
| aead_aes_gcm_siv_cleanup, |
| aead_aes_gcm_siv_seal, |
| aead_aes_gcm_siv_open, |
| NULL /* get_iv */, |
| }; |
| |
| static const EVP_AEAD aead_aes_256_gcm_siv = { |
| 32, /* key length */ |
| EVP_AEAD_AES_GCM_SIV_NONCE_LEN, /* nonce length */ |
| EVP_AEAD_AES_GCM_SIV_TAG_LEN, /* overhead */ |
| EVP_AEAD_AES_GCM_SIV_TAG_LEN, /* max tag length */ |
| |
| aead_aes_gcm_siv_init, |
| NULL /* init_with_direction */, |
| aead_aes_gcm_siv_cleanup, |
| aead_aes_gcm_siv_seal, |
| aead_aes_gcm_siv_open, |
| NULL /* get_iv */, |
| }; |
| |
| #if defined(OPENSSL_X86_64) && !defined(OPENSSL_NO_ASM) |
| |
| static char avx_aesni_capable(void) { |
| const uint32_t ecx = OPENSSL_ia32cap_P[1]; |
| |
| return (ecx & (1 << (57 - 32))) != 0 /* AESNI */ && |
| (ecx & (1 << 28)) != 0 /* AVX */; |
| } |
| |
| const EVP_AEAD *EVP_aead_aes_128_gcm_siv(void) { |
| if (avx_aesni_capable()) { |
| return &aead_aes_128_gcm_siv_asm; |
| } |
| return &aead_aes_128_gcm_siv; |
| } |
| |
| const EVP_AEAD *EVP_aead_aes_256_gcm_siv(void) { |
| if (avx_aesni_capable()) { |
| return &aead_aes_256_gcm_siv_asm; |
| } |
| return &aead_aes_256_gcm_siv; |
| } |
| |
| #else |
| |
| const EVP_AEAD *EVP_aead_aes_128_gcm_siv(void) { |
| return &aead_aes_128_gcm_siv; |
| } |
| |
| const EVP_AEAD *EVP_aead_aes_256_gcm_siv(void) { |
| return &aead_aes_256_gcm_siv; |
| } |
| |
| #endif /* X86_64 && !NO_ASM */ |
| |
| #endif /* !OPENSSL_SMALL */ |
