84 lines
2.4 KiB
C
84 lines
2.4 KiB
C
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/* $OpenBSD: e_chacha.c,v 1.8 2020/01/26 07:47:26 tb Exp $ */
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/*
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* Copyright (c) 2014 Joel Sing <jsing@openbsd.org>
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*
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* Permission to use, copy, modify, and 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
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* ANY 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
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include <openssl/opensslconf.h>
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#ifndef OPENSSL_NO_CHACHA
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#include <openssl/chacha.h>
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#include <openssl/evp.h>
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#include <openssl/objects.h>
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#include "evp_locl.h"
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static int chacha_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out,
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const unsigned char *in, size_t len);
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static int chacha_init(EVP_CIPHER_CTX *ctx, const unsigned char *key,
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const unsigned char *iv, int enc);
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static const EVP_CIPHER chacha20_cipher = {
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.nid = NID_chacha20,
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.block_size = 1,
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.key_len = 32,
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/*
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* The 128 bit EVP IV is split for ChaCha into four 32 bit pieces:
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* counter[0] counter[1] iv[0] iv[1]
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* OpenSSL exposes these as:
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* openssl_iv = counter[0] iv[0] iv[1] iv[2]
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* Due to the cipher internal state's symmetry, these are functionally
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* equivalent.
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*/
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.iv_len = 16,
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.flags = EVP_CIPH_STREAM_CIPHER | EVP_CIPH_ALWAYS_CALL_INIT |
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EVP_CIPH_CUSTOM_IV,
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.init = chacha_init,
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.do_cipher = chacha_cipher,
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.ctx_size = sizeof(ChaCha_ctx)
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};
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const EVP_CIPHER *
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EVP_chacha20(void)
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{
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return (&chacha20_cipher);
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}
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static int
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chacha_init(EVP_CIPHER_CTX *ctx, const unsigned char *key,
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const unsigned char *openssl_iv, int enc)
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{
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if (key != NULL)
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ChaCha_set_key((ChaCha_ctx *)ctx->cipher_data, key,
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EVP_CIPHER_CTX_key_length(ctx) * 8);
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if (openssl_iv != NULL) {
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const unsigned char *iv = openssl_iv + 8;
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const unsigned char *counter = openssl_iv;
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ChaCha_set_iv((ChaCha_ctx *)ctx->cipher_data, iv, counter);
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}
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return 1;
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}
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static int
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chacha_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out, const unsigned char *in,
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size_t len)
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{
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ChaCha((ChaCha_ctx *)ctx->cipher_data, out, in, len);
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return 1;
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}
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#endif
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