pigweed / third_party / boringssl / boringssl / 966284337d8cd531e6475c9afefbe1bb03e1cb64 / . / crypto / modes / cbc.c

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

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

* | |

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

* modification, are permitted provided that the following conditions | |

* are met: | |

* | |

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

* notice, this list of conditions and the following disclaimer. | |

* | |

* 2. Redistributions in binary form must reproduce the above copyright | |

* notice, this list of conditions and the following disclaimer in | |

* the documentation and/or other materials provided with the | |

* distribution. | |

* | |

* 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/)" | |

* | |

* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to | |

* endorse or promote products derived from this software without | |

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* openssl-core@openssl.org. | |

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* 5. Products derived from this software may not be called "OpenSSL" | |

* nor may "OpenSSL" appear in their names without prior written | |

* permission of the OpenSSL Project. | |

* | |

* 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/)" | |

* | |

* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY | |

* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |

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

#include <assert.h> | |

#include <string.h> | |

#include "internal.h" | |

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

const void *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)); | |

if (STRICT_ALIGNMENT && | |

((size_t)in | (size_t)out | (size_t)ivec) % sizeof(size_t) != 0) { | |

while (len >= 16) { | |

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

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

} | |

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

iv = out; | |

len -= 16; | |

in += 16; | |

out += 16; | |

} | |

} else { | |

while (len >= 16) { | |

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

*(size_t *)(out + n) = *(size_t *)(in + n) ^ *(size_t *)(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 void *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. */ | |

const uint8_t *iv = ivec; | |

if (STRICT_ALIGNMENT && | |

((size_t)in | (size_t)out | (size_t)ivec) % sizeof(size_t) != 0) { | |

while (len >= 16) { | |

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

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

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

} | |

iv = in; | |

len -= 16; | |

in += 16; | |

out += 16; | |

} | |

} else if (16 % sizeof(size_t) == 0) { /* always true */ | |

while (len >= 16) { | |

size_t *out_t = (size_t *)out, *iv_t = (size_t *)iv; | |

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

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

out_t[n] ^= iv_t[n]; | |

} | |

iv = in; | |

len -= 16; | |

in += 16; | |

out += 16; | |

} | |

} | |

OPENSSL_memcpy(ivec, iv, 16); | |

} else { | |

/* |out| is less than two blocks behind |in|. Decrypting an input block | |

* directly to |out| would overwrite a ciphertext block before it is used as | |

* the next block's IV. Decrypt to a temporary block instead. */ | |

if (STRICT_ALIGNMENT && | |

((size_t)in | (size_t)out | (size_t)ivec) % sizeof(size_t) != 0) { | |

uint8_t c; | |

while (len >= 16) { | |

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

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

c = in[n]; | |

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

ivec[n] = c; | |

} | |

len -= 16; | |

in += 16; | |

out += 16; | |

} | |

} else if (16 % sizeof(size_t) == 0) { /* always true */ | |

while (len >= 16) { | |

size_t c, *out_t = (size_t *)out, *ivec_t = (size_t *)ivec; | |

const size_t *in_t = (const size_t *)in; | |

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

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

c = in_t[n]; | |

out_t[n] = tmp.t[n] ^ ivec_t[n]; | |

ivec_t[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; | |

} | |

} |