884 lines
31 KiB
C
884 lines
31 KiB
C
/* Copyright (c) 2017, Google Inc.
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
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* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
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* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
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#include <openssl/aead.h>
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#include <assert.h>
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#include <openssl/cipher.h>
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#include <openssl/cpu.h>
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#include <openssl/crypto.h>
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#include <openssl/err.h>
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#include "../fipsmodule/cipher/internal.h"
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#define EVP_AEAD_AES_GCM_SIV_NONCE_LEN 12
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#define EVP_AEAD_AES_GCM_SIV_TAG_LEN 16
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// TODO(davidben): AES-GCM-SIV assembly is not correct for Windows. It must save
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// and restore xmm6 through xmm15.
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#if defined(OPENSSL_X86_64) && !defined(OPENSSL_NO_ASM) && \
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!defined(OPENSSL_WINDOWS)
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#define AES_GCM_SIV_ASM
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// Optimised AES-GCM-SIV
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struct aead_aes_gcm_siv_asm_ctx {
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alignas(16) uint8_t key[16*15];
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int is_128_bit;
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};
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// The assembly code assumes 8-byte alignment of the EVP_AEAD_CTX's state, and
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// aligns to 16 bytes itself.
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OPENSSL_STATIC_ASSERT(sizeof(((EVP_AEAD_CTX *)NULL)->state) + 8 >=
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sizeof(struct aead_aes_gcm_siv_asm_ctx),
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"AEAD state is too small");
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#if defined(__GNUC__) || defined(__clang__)
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OPENSSL_STATIC_ASSERT(alignof(union evp_aead_ctx_st_state) >= 8,
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"AEAD state has insufficient alignment");
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#endif
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// asm_ctx_from_ctx returns a 16-byte aligned context pointer from |ctx|.
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static struct aead_aes_gcm_siv_asm_ctx *asm_ctx_from_ctx(
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const EVP_AEAD_CTX *ctx) {
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// ctx->state must already be 8-byte aligned. Thus, at most, we may need to
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// add eight to align it to 16 bytes.
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const uintptr_t offset = ((uintptr_t)&ctx->state) & 8;
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return (struct aead_aes_gcm_siv_asm_ctx *)(&ctx->state.opaque[offset]);
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}
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// aes128gcmsiv_aes_ks writes an AES-128 key schedule for |key| to
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// |out_expanded_key|.
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extern void aes128gcmsiv_aes_ks(
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const uint8_t key[16], uint8_t out_expanded_key[16*15]);
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// aes256gcmsiv_aes_ks writes an AES-256 key schedule for |key| to
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// |out_expanded_key|.
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extern void aes256gcmsiv_aes_ks(
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const uint8_t key[32], uint8_t out_expanded_key[16*15]);
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static int aead_aes_gcm_siv_asm_init(EVP_AEAD_CTX *ctx, const uint8_t *key,
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size_t key_len, size_t tag_len) {
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const size_t key_bits = key_len * 8;
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if (key_bits != 128 && key_bits != 256) {
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OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BAD_KEY_LENGTH);
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return 0; // EVP_AEAD_CTX_init should catch this.
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}
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if (tag_len == EVP_AEAD_DEFAULT_TAG_LENGTH) {
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tag_len = EVP_AEAD_AES_GCM_SIV_TAG_LEN;
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}
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if (tag_len != EVP_AEAD_AES_GCM_SIV_TAG_LEN) {
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OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_TAG_TOO_LARGE);
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return 0;
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}
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struct aead_aes_gcm_siv_asm_ctx *gcm_siv_ctx = asm_ctx_from_ctx(ctx);
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assert((((uintptr_t)gcm_siv_ctx) & 15) == 0);
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if (key_bits == 128) {
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aes128gcmsiv_aes_ks(key, &gcm_siv_ctx->key[0]);
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gcm_siv_ctx->is_128_bit = 1;
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} else {
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aes256gcmsiv_aes_ks(key, &gcm_siv_ctx->key[0]);
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gcm_siv_ctx->is_128_bit = 0;
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}
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ctx->tag_len = tag_len;
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return 1;
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}
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static void aead_aes_gcm_siv_asm_cleanup(EVP_AEAD_CTX *ctx) {}
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// aesgcmsiv_polyval_horner updates the POLYVAL value in |in_out_poly| to
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// include a number (|in_blocks|) of 16-byte blocks of data from |in|, given
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// the POLYVAL key in |key|.
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extern void aesgcmsiv_polyval_horner(const uint8_t in_out_poly[16],
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const uint8_t key[16], const uint8_t *in,
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size_t in_blocks);
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// aesgcmsiv_htable_init writes powers 1..8 of |auth_key| to |out_htable|.
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extern void aesgcmsiv_htable_init(uint8_t out_htable[16 * 8],
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const uint8_t auth_key[16]);
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// aesgcmsiv_htable6_init writes powers 1..6 of |auth_key| to |out_htable|.
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extern void aesgcmsiv_htable6_init(uint8_t out_htable[16 * 6],
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const uint8_t auth_key[16]);
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// aesgcmsiv_htable_polyval updates the POLYVAL value in |in_out_poly| to
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// include |in_len| bytes of data from |in|. (Where |in_len| must be a multiple
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// of 16.) It uses the precomputed powers of the key given in |htable|.
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extern void aesgcmsiv_htable_polyval(const uint8_t htable[16 * 8],
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const uint8_t *in, size_t in_len,
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uint8_t in_out_poly[16]);
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// aes128gcmsiv_dec decrypts |in_len| & ~15 bytes from |out| and writes them to
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// |in|. (The full value of |in_len| is still used to find the authentication
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// tag appended to the ciphertext, however, so must not be pre-masked.)
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//
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// |in| and |out| may be equal, but must not otherwise overlap.
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//
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// While decrypting, it updates the POLYVAL value found at the beginning of
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// |in_out_calculated_tag_and_scratch| and writes the updated value back before
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// return. During executation, it may use the whole of this space for other
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// purposes. In order to decrypt and update the POLYVAL value, it uses the
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// expanded key from |key| and the table of powers in |htable|.
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extern void aes128gcmsiv_dec(const uint8_t *in, uint8_t *out,
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uint8_t in_out_calculated_tag_and_scratch[16 * 8],
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const uint8_t htable[16 * 6],
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const struct aead_aes_gcm_siv_asm_ctx *key,
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size_t in_len);
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// aes256gcmsiv_dec acts like |aes128gcmsiv_dec|, but for AES-256.
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extern void aes256gcmsiv_dec(const uint8_t *in, uint8_t *out,
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uint8_t in_out_calculated_tag_and_scratch[16 * 8],
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const uint8_t htable[16 * 6],
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const struct aead_aes_gcm_siv_asm_ctx *key,
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size_t in_len);
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// aes128gcmsiv_kdf performs the AES-GCM-SIV KDF given the expanded key from
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// |key_schedule| and the nonce in |nonce|. Note that, while only 12 bytes of
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// the nonce are used, 16 bytes are read and so the value must be
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// right-padded.
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extern void aes128gcmsiv_kdf(const uint8_t nonce[16],
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uint64_t out_key_material[8],
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const uint8_t *key_schedule);
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// aes256gcmsiv_kdf acts like |aes128gcmsiv_kdf|, but for AES-256.
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extern void aes256gcmsiv_kdf(const uint8_t nonce[16],
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uint64_t out_key_material[12],
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const uint8_t *key_schedule);
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// aes128gcmsiv_aes_ks_enc_x1 performs a key expansion of the AES-128 key in
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// |key|, writes the expanded key to |out_expanded_key| and encrypts a single
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// block from |in| to |out|.
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extern void aes128gcmsiv_aes_ks_enc_x1(const uint8_t in[16], uint8_t out[16],
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uint8_t out_expanded_key[16 * 15],
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const uint64_t key[2]);
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// aes256gcmsiv_aes_ks_enc_x1 acts like |aes128gcmsiv_aes_ks_enc_x1|, but for
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// AES-256.
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extern void aes256gcmsiv_aes_ks_enc_x1(const uint8_t in[16], uint8_t out[16],
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uint8_t out_expanded_key[16 * 15],
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const uint64_t key[4]);
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// aes128gcmsiv_ecb_enc_block encrypts a single block from |in| to |out| using
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// the expanded key in |expanded_key|.
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extern void aes128gcmsiv_ecb_enc_block(
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const uint8_t in[16], uint8_t out[16],
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const struct aead_aes_gcm_siv_asm_ctx *expanded_key);
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// aes256gcmsiv_ecb_enc_block acts like |aes128gcmsiv_ecb_enc_block|, but for
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// AES-256.
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extern void aes256gcmsiv_ecb_enc_block(
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const uint8_t in[16], uint8_t out[16],
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const struct aead_aes_gcm_siv_asm_ctx *expanded_key);
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// aes128gcmsiv_enc_msg_x4 encrypts |in_len| bytes from |in| to |out| using the
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// expanded key from |key|. (The value of |in_len| must be a multiple of 16.)
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// The |in| and |out| buffers may be equal but must not otherwise overlap. The
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// initial counter is constructed from the given |tag| as required by
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// AES-GCM-SIV.
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extern void aes128gcmsiv_enc_msg_x4(const uint8_t *in, uint8_t *out,
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const uint8_t *tag,
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const struct aead_aes_gcm_siv_asm_ctx *key,
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size_t in_len);
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// aes256gcmsiv_enc_msg_x4 acts like |aes128gcmsiv_enc_msg_x4|, but for
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// AES-256.
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extern void aes256gcmsiv_enc_msg_x4(const uint8_t *in, uint8_t *out,
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const uint8_t *tag,
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const struct aead_aes_gcm_siv_asm_ctx *key,
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size_t in_len);
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// aes128gcmsiv_enc_msg_x8 acts like |aes128gcmsiv_enc_msg_x4|, but is
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// optimised for longer messages.
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extern void aes128gcmsiv_enc_msg_x8(const uint8_t *in, uint8_t *out,
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const uint8_t *tag,
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const struct aead_aes_gcm_siv_asm_ctx *key,
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size_t in_len);
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// aes256gcmsiv_enc_msg_x8 acts like |aes256gcmsiv_enc_msg_x4|, but is
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// optimised for longer messages.
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extern void aes256gcmsiv_enc_msg_x8(const uint8_t *in, uint8_t *out,
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const uint8_t *tag,
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const struct aead_aes_gcm_siv_asm_ctx *key,
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size_t in_len);
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// gcm_siv_asm_polyval evaluates POLYVAL at |auth_key| on the given plaintext
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// and AD. The result is written to |out_tag|.
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static void gcm_siv_asm_polyval(uint8_t out_tag[16], const uint8_t *in,
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size_t in_len, const uint8_t *ad, size_t ad_len,
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const uint8_t auth_key[16],
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const uint8_t nonce[12]) {
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OPENSSL_memset(out_tag, 0, 16);
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const size_t ad_blocks = ad_len / 16;
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const size_t in_blocks = in_len / 16;
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int htable_init = 0;
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alignas(16) uint8_t htable[16*8];
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if (ad_blocks > 8 || in_blocks > 8) {
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htable_init = 1;
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aesgcmsiv_htable_init(htable, auth_key);
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}
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if (htable_init) {
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aesgcmsiv_htable_polyval(htable, ad, ad_len & ~15, out_tag);
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} else {
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aesgcmsiv_polyval_horner(out_tag, auth_key, ad, ad_blocks);
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}
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uint8_t scratch[16];
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if (ad_len & 15) {
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OPENSSL_memset(scratch, 0, sizeof(scratch));
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OPENSSL_memcpy(scratch, &ad[ad_len & ~15], ad_len & 15);
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aesgcmsiv_polyval_horner(out_tag, auth_key, scratch, 1);
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}
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if (htable_init) {
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aesgcmsiv_htable_polyval(htable, in, in_len & ~15, out_tag);
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} else {
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aesgcmsiv_polyval_horner(out_tag, auth_key, in, in_blocks);
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}
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if (in_len & 15) {
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OPENSSL_memset(scratch, 0, sizeof(scratch));
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OPENSSL_memcpy(scratch, &in[in_len & ~15], in_len & 15);
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aesgcmsiv_polyval_horner(out_tag, auth_key, scratch, 1);
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}
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union {
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uint8_t c[16];
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struct {
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uint64_t ad;
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uint64_t in;
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} bitlens;
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} length_block;
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length_block.bitlens.ad = ad_len * 8;
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length_block.bitlens.in = in_len * 8;
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aesgcmsiv_polyval_horner(out_tag, auth_key, length_block.c, 1);
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for (size_t i = 0; i < 12; i++) {
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out_tag[i] ^= nonce[i];
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}
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out_tag[15] &= 0x7f;
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}
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// aead_aes_gcm_siv_asm_crypt_last_block handles the encryption/decryption
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// (same thing in CTR mode) of the final block of a plaintext/ciphertext. It
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// writes |in_len| & 15 bytes to |out| + |in_len|, based on an initial counter
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// derived from |tag|.
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static void aead_aes_gcm_siv_asm_crypt_last_block(
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int is_128_bit, uint8_t *out, const uint8_t *in, size_t in_len,
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const uint8_t tag[16],
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const struct aead_aes_gcm_siv_asm_ctx *enc_key_expanded) {
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alignas(16) union {
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uint8_t c[16];
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uint32_t u32[4];
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} counter;
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OPENSSL_memcpy(&counter, tag, sizeof(counter));
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counter.c[15] |= 0x80;
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counter.u32[0] += in_len / 16;
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if (is_128_bit) {
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aes128gcmsiv_ecb_enc_block(&counter.c[0], &counter.c[0], enc_key_expanded);
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} else {
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aes256gcmsiv_ecb_enc_block(&counter.c[0], &counter.c[0], enc_key_expanded);
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}
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const size_t last_bytes_offset = in_len & ~15;
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const size_t last_bytes_len = in_len & 15;
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uint8_t *last_bytes_out = &out[last_bytes_offset];
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const uint8_t *last_bytes_in = &in[last_bytes_offset];
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for (size_t i = 0; i < last_bytes_len; i++) {
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last_bytes_out[i] = last_bytes_in[i] ^ counter.c[i];
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}
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}
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// aead_aes_gcm_siv_kdf calculates the record encryption and authentication
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// keys given the |nonce|.
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static void aead_aes_gcm_siv_kdf(
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int is_128_bit, const struct aead_aes_gcm_siv_asm_ctx *gcm_siv_ctx,
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uint64_t out_record_auth_key[2], uint64_t out_record_enc_key[4],
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const uint8_t nonce[12]) {
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alignas(16) uint8_t padded_nonce[16];
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OPENSSL_memcpy(padded_nonce, nonce, 12);
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alignas(16) uint64_t key_material[12];
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if (is_128_bit) {
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aes128gcmsiv_kdf(padded_nonce, key_material, &gcm_siv_ctx->key[0]);
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out_record_enc_key[0] = key_material[4];
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out_record_enc_key[1] = key_material[6];
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} else {
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aes256gcmsiv_kdf(padded_nonce, key_material, &gcm_siv_ctx->key[0]);
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out_record_enc_key[0] = key_material[4];
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out_record_enc_key[1] = key_material[6];
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out_record_enc_key[2] = key_material[8];
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out_record_enc_key[3] = key_material[10];
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}
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out_record_auth_key[0] = key_material[0];
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out_record_auth_key[1] = key_material[2];
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}
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static int aead_aes_gcm_siv_asm_seal_scatter(
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const EVP_AEAD_CTX *ctx, uint8_t *out, uint8_t *out_tag,
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size_t *out_tag_len, size_t max_out_tag_len, const uint8_t *nonce,
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size_t nonce_len, const uint8_t *in, size_t in_len, const uint8_t *extra_in,
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size_t extra_in_len, const uint8_t *ad, size_t ad_len) {
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const struct aead_aes_gcm_siv_asm_ctx *gcm_siv_ctx = asm_ctx_from_ctx(ctx);
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const uint64_t in_len_64 = in_len;
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const uint64_t ad_len_64 = ad_len;
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if (in_len_64 > (UINT64_C(1) << 36) ||
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ad_len_64 >= (UINT64_C(1) << 61)) {
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OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_TOO_LARGE);
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return 0;
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}
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if (max_out_tag_len < EVP_AEAD_AES_GCM_SIV_TAG_LEN) {
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OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BUFFER_TOO_SMALL);
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return 0;
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}
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if (nonce_len != EVP_AEAD_AES_GCM_SIV_NONCE_LEN) {
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OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_UNSUPPORTED_NONCE_SIZE);
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return 0;
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}
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alignas(16) uint64_t record_auth_key[2];
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alignas(16) uint64_t record_enc_key[4];
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aead_aes_gcm_siv_kdf(gcm_siv_ctx->is_128_bit, gcm_siv_ctx, record_auth_key,
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record_enc_key, nonce);
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alignas(16) uint8_t tag[16] = {0};
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gcm_siv_asm_polyval(tag, in, in_len, ad, ad_len,
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(const uint8_t *)record_auth_key, nonce);
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struct aead_aes_gcm_siv_asm_ctx enc_key_expanded;
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if (gcm_siv_ctx->is_128_bit) {
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aes128gcmsiv_aes_ks_enc_x1(tag, tag, &enc_key_expanded.key[0],
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record_enc_key);
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if (in_len < 128) {
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aes128gcmsiv_enc_msg_x4(in, out, tag, &enc_key_expanded, in_len & ~15);
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} else {
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aes128gcmsiv_enc_msg_x8(in, out, tag, &enc_key_expanded, in_len & ~15);
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}
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} else {
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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_tag, tag, sizeof(tag));
|
|
*out_tag_len = EVP_AEAD_AES_GCM_SIV_TAG_LEN;
|
|
|
|
return 1;
|
|
}
|
|
|
|
// TODO(martinkr): Add aead_aes_gcm_siv_asm_open_gather. N.B. aes128gcmsiv_dec
|
|
// expects ciphertext and tag in a contiguous buffer.
|
|
|
|
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;
|
|
}
|
|
|
|
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_asm_ctx *gcm_siv_ctx = asm_ctx_from_ctx(ctx);
|
|
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
|
|
0, // seal_scatter_supports_extra_in
|
|
|
|
aead_aes_gcm_siv_asm_init,
|
|
NULL /* init_with_direction */,
|
|
aead_aes_gcm_siv_asm_cleanup,
|
|
aead_aes_gcm_siv_asm_open,
|
|
aead_aes_gcm_siv_asm_seal_scatter,
|
|
NULL /* open_gather */,
|
|
NULL /* get_iv */,
|
|
NULL /* tag_len */,
|
|
};
|
|
|
|
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
|
|
0, // seal_scatter_supports_extra_in
|
|
|
|
aead_aes_gcm_siv_asm_init,
|
|
NULL /* init_with_direction */,
|
|
aead_aes_gcm_siv_asm_cleanup,
|
|
aead_aes_gcm_siv_asm_open,
|
|
aead_aes_gcm_siv_asm_seal_scatter,
|
|
NULL /* open_gather */,
|
|
NULL /* get_iv */,
|
|
NULL /* tag_len */,
|
|
};
|
|
|
|
#endif // X86_64 && !NO_ASM && !WINDOWS
|
|
|
|
struct aead_aes_gcm_siv_ctx {
|
|
union {
|
|
double align;
|
|
AES_KEY ks;
|
|
} ks;
|
|
block128_f kgk_block;
|
|
unsigned is_256:1;
|
|
};
|
|
|
|
OPENSSL_STATIC_ASSERT(sizeof(((EVP_AEAD_CTX *)NULL)->state) >=
|
|
sizeof(struct aead_aes_gcm_siv_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_gcm_siv_ctx),
|
|
"AEAD state has insufficient alignment");
|
|
#endif
|
|
|
|
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 =
|
|
(struct aead_aes_gcm_siv_ctx *)&ctx->state;
|
|
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->tag_len = tag_len;
|
|
|
|
return 1;
|
|
}
|
|
|
|
static void aead_aes_gcm_siv_cleanup(EVP_AEAD_CTX *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_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_gcm_siv_ctx *gcm_siv_ctx =
|
|
(struct aead_aes_gcm_siv_ctx *)&ctx->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_tag_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_tag, tag, EVP_AEAD_AES_GCM_SIV_TAG_LEN);
|
|
*out_tag_len = EVP_AEAD_AES_GCM_SIV_TAG_LEN;
|
|
|
|
return 1;
|
|
}
|
|
|
|
static int aead_aes_gcm_siv_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 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_tag_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 =
|
|
(struct aead_aes_gcm_siv_ctx *)&ctx->state;
|
|
|
|
struct gcm_siv_record_keys keys;
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gcm_siv_keys(gcm_siv_ctx, &keys, nonce);
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|
|
|
gcm_siv_crypt(out, in, in_len, in_tag, keys.enc_block, &keys.enc_key.ks);
|
|
|
|
uint8_t expected_tag[EVP_AEAD_AES_GCM_SIV_TAG_LEN];
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gcm_siv_polyval(expected_tag, out, in_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_tag, sizeof(expected_tag)) != 0) {
|
|
OPENSSL_PUT_ERROR(CIPHER, CIPHER_R_BAD_DECRYPT);
|
|
return 0;
|
|
}
|
|
|
|
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
|
|
0, // seal_scatter_supports_extra_in
|
|
|
|
aead_aes_gcm_siv_init,
|
|
NULL /* init_with_direction */,
|
|
aead_aes_gcm_siv_cleanup,
|
|
NULL /* open */,
|
|
aead_aes_gcm_siv_seal_scatter,
|
|
aead_aes_gcm_siv_open_gather,
|
|
NULL /* get_iv */,
|
|
NULL /* tag_len */,
|
|
};
|
|
|
|
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
|
|
0, // seal_scatter_supports_extra_in
|
|
|
|
aead_aes_gcm_siv_init,
|
|
NULL /* init_with_direction */,
|
|
aead_aes_gcm_siv_cleanup,
|
|
NULL /* open */,
|
|
aead_aes_gcm_siv_seal_scatter,
|
|
aead_aes_gcm_siv_open_gather,
|
|
NULL /* get_iv */,
|
|
NULL /* tag_len */,
|
|
};
|
|
|
|
#if defined(AES_GCM_SIV_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 // AES_GCM_SIV_ASM
|