boringssl / boringssl / 6c95434cc9876dfe1cdc375c5ff04e70ebfe3770 / . / crypto / fipsmodule / modes / cbc.c

/* ==================================================================== | |

* Copyright (c) 2008 The OpenSSL Project. All rights reserved. | |

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* Redistribution and use in source and binary forms, with or without | |

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* 1. Redistributions of source code must retain the above copyright | |

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* 3. All advertising materials mentioning features or use of this | |

* software must display the following acknowledgment: | |

* "This product includes software developed by the OpenSSL Project | |

* for use in the OpenSSL Toolkit. (http://www.openssl.org/)" | |

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* 6. Redistributions of any form whatsoever must retain the following | |

* acknowledgment: | |

* "This product includes software developed by the OpenSSL Project | |

* for use in the OpenSSL Toolkit (http://www.openssl.org/)" | |

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#include <assert.h> | |

#include <string.h> | |

#include <openssl/type_check.h> | |

#include "internal.h" | |

void CRYPTO_cbc128_encrypt(const uint8_t *in, uint8_t *out, size_t len, | |

const AES_KEY *key, uint8_t ivec[16], | |

block128_f block) { | |

size_t n; | |

const uint8_t *iv = ivec; | |

assert(key != NULL && ivec != NULL); | |

assert(len == 0 || (in != NULL && out != NULL)); | |

while (len >= 16) { | |

for (n = 0; n < 16; n += sizeof(size_t)) { | |

store_word_le(out + n, load_word_le(in + n) ^ load_word_le(iv + n)); | |

} | |

(*block)(out, out, key); | |

iv = out; | |

len -= 16; | |

in += 16; | |

out += 16; | |

} | |

while (len) { | |

for (n = 0; n < 16 && n < len; ++n) { | |

out[n] = in[n] ^ iv[n]; | |

} | |

for (; n < 16; ++n) { | |

out[n] = iv[n]; | |

} | |

(*block)(out, out, key); | |

iv = out; | |

if (len <= 16) { | |

break; | |

} | |

len -= 16; | |

in += 16; | |

out += 16; | |

} | |

OPENSSL_memcpy(ivec, iv, 16); | |

} | |

void CRYPTO_cbc128_decrypt(const uint8_t *in, uint8_t *out, size_t len, | |

const AES_KEY *key, uint8_t ivec[16], | |

block128_f block) { | |

size_t n; | |

union { | |

size_t t[16 / sizeof(size_t)]; | |

uint8_t c[16]; | |

} tmp; | |

assert(key != NULL && ivec != NULL); | |

assert(len == 0 || (in != NULL && out != NULL)); | |

const uintptr_t inptr = (uintptr_t) in; | |

const uintptr_t outptr = (uintptr_t) out; | |

// If |in| and |out| alias, |in| must be ahead. | |

assert(inptr >= outptr || inptr + len <= outptr); | |

if ((inptr >= 32 && outptr <= inptr - 32) || inptr < outptr) { | |

// If |out| is at least two blocks behind |in| or completely disjoint, there | |

// is no need to decrypt to a temporary block. | |

OPENSSL_STATIC_ASSERT(16 % sizeof(size_t) == 0, | |

"block cannot be evenly divided into words"); | |

const uint8_t *iv = ivec; | |

while (len >= 16) { | |

(*block)(in, out, key); | |

for (n = 0; n < 16; n += sizeof(size_t)) { | |

store_word_le(out + n, load_word_le(out + n) ^ load_word_le(iv + n)); | |

} | |

iv = in; | |

len -= 16; | |

in += 16; | |

out += 16; | |

} | |

OPENSSL_memcpy(ivec, iv, 16); | |

} else { | |

OPENSSL_STATIC_ASSERT(16 % sizeof(size_t) == 0, | |

"block cannot be evenly divided into words"); | |

while (len >= 16) { | |

(*block)(in, tmp.c, key); | |

for (n = 0; n < 16; n += sizeof(size_t)) { | |

size_t c = load_word_le(in + n); | |

store_word_le(out + n, | |

tmp.t[n / sizeof(size_t)] ^ load_word_le(ivec + n)); | |

store_word_le(ivec + n, c); | |

} | |

len -= 16; | |

in += 16; | |

out += 16; | |

} | |

} | |

while (len) { | |

uint8_t c; | |

(*block)(in, tmp.c, key); | |

for (n = 0; n < 16 && n < len; ++n) { | |

c = in[n]; | |

out[n] = tmp.c[n] ^ ivec[n]; | |

ivec[n] = c; | |

} | |

if (len <= 16) { | |

for (; n < 16; ++n) { | |

ivec[n] = in[n]; | |

} | |

break; | |

} | |

len -= 16; | |

in += 16; | |

out += 16; | |

} | |

} |