116 lines
2.9 KiB
C
116 lines
2.9 KiB
C
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// Copyright (c) 2008 The OpenSSL Project. All rights reserved.
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// SPDX-License-Identifier: Apache-2.0
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#include <assert.h>
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#include <string.h>
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#include <openssl/type_check.h>
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#include "internal.h"
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#include "../../internal.h"
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void CRYPTO_cbc128_encrypt(const uint8_t *in, uint8_t *out, size_t len,
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const AES_KEY *key, uint8_t ivec[16],
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block128_f block) {
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assert(key != NULL && ivec != NULL);
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if (len == 0) {
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// Avoid |ivec| == |iv| in the |memcpy| below, which is not legal in C.
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return;
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}
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assert(in != NULL && out != NULL);
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size_t n;
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const uint8_t *iv = ivec;
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while (len >= 16) {
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CRYPTO_xor16(out, in, iv);
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(*block)(out, out, key);
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iv = out;
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len -= 16;
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in += 16;
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out += 16;
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}
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if (len > 0) {
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for (n = 0; n < 16 && n < len; ++n) {
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out[n] = in[n] ^ iv[n];
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}
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for (; n < 16; ++n) {
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out[n] = iv[n];
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}
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(*block)(out, out, key);
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iv = out;
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}
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OPENSSL_memcpy(ivec, iv, 16);
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}
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void CRYPTO_cbc128_decrypt(const uint8_t *in, uint8_t *out, size_t len,
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const AES_KEY *key, uint8_t ivec[16],
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block128_f block) {
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assert(key != NULL && ivec != NULL);
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if (len == 0) {
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// Avoid |ivec| == |iv| in the |memcpy| below, which is not legal in C.
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return;
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}
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assert(in != NULL && out != NULL);
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const uintptr_t inptr = (uintptr_t) in;
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const uintptr_t outptr = (uintptr_t) out;
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// If |in| and |out| alias, |in| must be ahead.
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assert(inptr >= outptr || inptr + len <= outptr);
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size_t n;
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alignas(16) uint8_t tmp[16];
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if ((inptr >= 32 && outptr <= inptr - 32) || inptr < outptr) {
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// If |out| is at least two blocks behind |in| or completely disjoint, there
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// is no need to decrypt to a temporary block.
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const uint8_t *iv = ivec;
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while (len >= 16) {
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(*block)(in, out, key);
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CRYPTO_xor16(out, out, iv);
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iv = in;
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len -= 16;
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in += 16;
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out += 16;
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}
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OPENSSL_memcpy(ivec, iv, 16);
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} else {
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OPENSSL_STATIC_ASSERT(16 % sizeof(crypto_word_t) == 0,
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block_cannot_be_evenly_divided_into_crypto_word_t)
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while (len >= 16) {
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(*block)(in, tmp, key);
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for (n = 0; n < 16; n += sizeof(crypto_word_t)) {
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crypto_word_t c = CRYPTO_load_word_le(in + n);
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CRYPTO_store_word_le(out + n, CRYPTO_load_word_le(tmp + n) ^
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CRYPTO_load_word_le(ivec + n));
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CRYPTO_store_word_le(ivec + n, c);
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}
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len -= 16;
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in += 16;
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out += 16;
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}
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}
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while (len) {
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uint8_t c;
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(*block)(in, tmp, key);
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for (n = 0; n < 16 && n < len; ++n) {
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c = in[n];
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out[n] = tmp[n] ^ ivec[n];
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ivec[n] = c;
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}
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if (len <= 16) {
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for (; n < 16; ++n) {
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ivec[n] = in[n];
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}
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break;
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}
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len -= 16;
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in += 16;
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out += 16;
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}
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}
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