1 /* $OpenBSD: ofb128.c,v 1.7 2023/07/08 14:56:54 beck Exp $ */ 2 /* ==================================================================== 3 * Copyright (c) 2008 The OpenSSL Project. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in 14 * the documentation and/or other materials provided with the 15 * distribution. 16 * 17 * 3. All advertising materials mentioning features or use of this 18 * software must display the following acknowledgment: 19 * "This product includes software developed by the OpenSSL Project 20 * for use in the OpenSSL Toolkit. (http://www.openssl.org/)" 21 * 22 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to 23 * endorse or promote products derived from this software without 24 * prior written permission. For written permission, please contact 25 * openssl-core@openssl.org. 26 * 27 * 5. Products derived from this software may not be called "OpenSSL" 28 * nor may "OpenSSL" appear in their names without prior written 29 * permission of the OpenSSL Project. 30 * 31 * 6. Redistributions of any form whatsoever must retain the following 32 * acknowledgment: 33 * "This product includes software developed by the OpenSSL Project 34 * for use in the OpenSSL Toolkit (http://www.openssl.org/)" 35 * 36 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY 37 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 38 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 39 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR 40 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 41 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 42 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 43 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 44 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 45 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 46 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED 47 * OF THE POSSIBILITY OF SUCH DAMAGE. 48 * ==================================================================== 49 * 50 */ 51 52 #include <openssl/crypto.h> 53 #include "modes_local.h" 54 #include <string.h> 55 56 #ifndef MODES_DEBUG 57 # ifndef NDEBUG 58 # define NDEBUG 59 # endif 60 #endif 61 62 /* The input and output encrypted as though 128bit ofb mode is being 63 * used. The extra state information to record how much of the 64 * 128bit block we have used is contained in *num; 65 */ 66 void 67 CRYPTO_ofb128_encrypt(const unsigned char *in, unsigned char *out, 68 size_t len, const void *key, 69 unsigned char ivec[16], int *num, 70 block128_f block) 71 { 72 unsigned int n; 73 size_t l = 0; 74 75 n = *num; 76 77 #if !defined(OPENSSL_SMALL_FOOTPRINT) 78 if (16 % sizeof(size_t) == 0) 79 do { /* always true actually */ 80 while (n && len) { 81 *(out++) = *(in++) ^ ivec[n]; 82 --len; 83 n = (n + 1) % 16; 84 } 85 #ifdef __STRICT_ALIGNMENT 86 if (((size_t)in|(size_t)out|(size_t)ivec) % 87 sizeof(size_t) != 0) 88 break; 89 #endif 90 while (len >= 16) { 91 (*block)(ivec, ivec, key); 92 for (; n < 16; n += sizeof(size_t)) 93 *(size_t *)(out + n) = 94 *(size_t *)(in + n) ^ *(size_t *)(ivec + 95 n); 96 len -= 16; 97 out += 16; 98 in += 16; 99 n = 0; 100 } 101 if (len) { 102 (*block)(ivec, ivec, key); 103 while (len--) { 104 out[n] = in[n] ^ ivec[n]; 105 ++n; 106 } 107 } 108 *num = n; 109 return; 110 } while (0); 111 /* the rest would be commonly eliminated by x86* compiler */ 112 #endif 113 while (l < len) { 114 if (n == 0) { 115 (*block)(ivec, ivec, key); 116 } 117 out[l] = in[l] ^ ivec[n]; 118 ++l; 119 n = (n + 1) % 16; 120 } 121 122 *num = n; 123 } 124 LCRYPTO_ALIAS(CRYPTO_ofb128_encrypt); 125