/* $OpenBSD: cfb128.c,v 1.4 2015/02/10 09:46:30 miod Exp $ */ /* ==================================================================== * 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 * prior written permission. For written permission, please contact * openssl-core@openssl.org. * * 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 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED * OF THE POSSIBILITY OF SUCH DAMAGE. * ==================================================================== * */ #include <openssl/crypto.h> #include "modes_lcl.h" #include <string.h> #ifndef MODES_DEBUG # ifndef NDEBUG # define NDEBUG # endif #endif /* The input and output encrypted as though 128bit cfb mode is being * used. The extra state information to record how much of the * 128bit block we have used is contained in *num; */ void CRYPTO_cfb128_encrypt(const unsigned char *in, unsigned char *out, size_t len, const void *key, unsigned char ivec[16], int *num, int enc, block128_f block) { unsigned int n; size_t l = 0; n = *num; if (enc) { #if !defined(OPENSSL_SMALL_FOOTPRINT) if (16%sizeof(size_t) == 0) do { /* always true actually */ while (n && len) { *(out++) = ivec[n] ^= *(in++); --len; n = (n+1) % 16; } #ifdef __STRICT_ALIGNMENT if (((size_t)in|(size_t)out|(size_t)ivec)%sizeof(size_t) != 0) break; #endif while (len>=16) { (*block)(ivec, ivec, key); for (; n<16; n+=sizeof(size_t)) { *(size_t*)(out+n) = *(size_t*)(ivec+n) ^= *(size_t*)(in+n); } len -= 16; out += 16; in += 16; n = 0; } if (len) { (*block)(ivec, ivec, key); while (len--) { out[n] = ivec[n] ^= in[n]; ++n; } } *num = n; return; } while (0); /* the rest would be commonly eliminated by x86* compiler */ #endif while (l<len) { if (n == 0) { (*block)(ivec, ivec, key); } out[l] = ivec[n] ^= in[l]; ++l; n = (n+1) % 16; } *num = n; } else { #if !defined(OPENSSL_SMALL_FOOTPRINT) if (16%sizeof(size_t) == 0) do { /* always true actually */ while (n && len) { unsigned char c; *(out++) = ivec[n] ^ (c = *(in++)); ivec[n] = c; --len; n = (n+1) % 16; } #ifdef __STRICT_ALIGNMENT if (((size_t)in|(size_t)out|(size_t)ivec)%sizeof(size_t) != 0) break; #endif while (len>=16) { (*block)(ivec, ivec, key); for (; n<16; n+=sizeof(size_t)) { size_t t = *(size_t*)(in+n); *(size_t*)(out+n) = *(size_t*)(ivec+n) ^ t; *(size_t*)(ivec+n) = t; } len -= 16; out += 16; in += 16; n = 0; } if (len) { (*block)(ivec, ivec, key); while (len--) { unsigned char c; out[n] = ivec[n] ^ (c = in[n]); ivec[n] = c; ++n; } } *num = n; return; } while (0); /* the rest would be commonly eliminated by x86* compiler */ #endif while (l<len) { unsigned char c; if (n == 0) { (*block)(ivec, ivec, key); } out[l] = ivec[n] ^ (c = in[l]); ivec[n] = c; ++l; n = (n+1) % 16; } *num=n; } } /* This expects a single block of size nbits for both in and out. Note that it corrupts any extra bits in the last byte of out */ static void cfbr_encrypt_block(const unsigned char *in,unsigned char *out, int nbits,const void *key, unsigned char ivec[16],int enc, block128_f block) { int n,rem,num; unsigned char ovec[16*2 + 1]; /* +1 because we dererefence (but don't use) one byte off the end */ if (nbits<=0 || nbits>128) return; /* fill in the first half of the new IV with the current IV */ memcpy(ovec,ivec,16); /* construct the new IV */ (*block)(ivec,ivec,key); num = (nbits+7)/8; if (enc) /* encrypt the input */ for(n=0 ; n < num ; ++n) out[n] = (ovec[16+n] = in[n] ^ ivec[n]); else /* decrypt the input */ for(n=0 ; n < num ; ++n) out[n] = (ovec[16+n] = in[n]) ^ ivec[n]; /* shift ovec left... */ rem = nbits%8; num = nbits/8; if(rem==0) memcpy(ivec,ovec+num,16); else for(n=0 ; n < 16 ; ++n) ivec[n] = ovec[n+num]<<rem | ovec[n+num+1]>>(8-rem); /* it is not necessary to cleanse ovec, since the IV is not secret */ } /* N.B. This expects the input to be packed, MS bit first */ void CRYPTO_cfb128_1_encrypt(const unsigned char *in, unsigned char *out, size_t bits, const void *key, unsigned char ivec[16], int *num, int enc, block128_f block) { size_t n; unsigned char c[1],d[1]; for(n=0 ; n<bits ; ++n) { c[0]=(in[n/8]&(1 << (7-n%8))) ? 0x80 : 0; cfbr_encrypt_block(c,d,1,key,ivec,enc,block); out[n/8]=(out[n/8]&~(1 << (unsigned int)(7-n%8))) | ((d[0]&0x80) >> (unsigned int)(n%8)); } } void CRYPTO_cfb128_8_encrypt(const unsigned char *in, unsigned char *out, size_t length, const void *key, unsigned char ivec[16], int *num, int enc, block128_f block) { size_t n; for(n=0 ; n<length ; ++n) cfbr_encrypt_block(&in[n],&out[n],8,key,ivec,enc,block); }
