[331] | 1 | /*
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| 2 | * Copyright 2008-2016 The OpenSSL Project Authors. All Rights Reserved.
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| 3 | *
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| 4 | * Licensed under the OpenSSL license (the "License"). You may not use
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| 5 | * this file except in compliance with the License. You can obtain a copy
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| 6 | * in the file LICENSE in the source distribution or at
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| 7 | * https://www.openssl.org/source/license.html
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| 8 | */
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| 9 |
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| 10 | #include <openssl/crypto.h>
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| 11 | #include "modes_lcl.h"
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| 12 | #include <string.h>
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| 13 |
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| 14 | /*
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| 15 | * The input and output encrypted as though 128bit ofb mode is being used.
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| 16 | * The extra state information to record how much of the 128bit block we have
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| 17 | * used is contained in *num;
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| 18 | */
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| 19 | void CRYPTO_ofb128_encrypt(const unsigned char *in, unsigned char *out,
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| 20 | size_t len, const void *key,
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| 21 | unsigned char ivec[16], int *num, block128_f block)
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| 22 | {
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| 23 | unsigned int n;
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| 24 | size_t l = 0;
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| 25 |
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| 26 | n = *num;
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| 27 |
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| 28 | #if !defined(OPENSSL_SMALL_FOOTPRINT)
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| 29 | if (16 % sizeof(size_t) == 0) { /* always true actually */
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| 30 | do {
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| 31 | while (n && len) {
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| 32 | *(out++) = *(in++) ^ ivec[n];
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| 33 | --len;
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| 34 | n = (n + 1) % 16;
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| 35 | }
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| 36 | # if defined(STRICT_ALIGNMENT)
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| 37 | if (((size_t)in | (size_t)out | (size_t)ivec) % sizeof(size_t) !=
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| 38 | 0)
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| 39 | break;
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| 40 | # endif
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| 41 | while (len >= 16) {
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| 42 | (*block) (ivec, ivec, key);
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| 43 | for (; n < 16; n += sizeof(size_t))
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| 44 | *(size_t *)(out + n) =
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| 45 | *(size_t *)(in + n) ^ *(size_t *)(ivec + n);
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| 46 | len -= 16;
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| 47 | out += 16;
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| 48 | in += 16;
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| 49 | n = 0;
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| 50 | }
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| 51 | if (len) {
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| 52 | (*block) (ivec, ivec, key);
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| 53 | while (len--) {
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| 54 | out[n] = in[n] ^ ivec[n];
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| 55 | ++n;
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| 56 | }
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| 57 | }
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| 58 | *num = n;
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| 59 | return;
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| 60 | } while (0);
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| 61 | }
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| 62 | /* the rest would be commonly eliminated by x86* compiler */
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| 63 | #endif
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| 64 | while (l < len) {
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| 65 | if (n == 0) {
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| 66 | (*block) (ivec, ivec, key);
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| 67 | }
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| 68 | out[l] = in[l] ^ ivec[n];
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| 69 | ++l;
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| 70 | n = (n + 1) % 16;
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| 71 | }
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| 72 |
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| 73 | *num = n;
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| 74 | }
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