/* ==================================================================== * 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/type_check.h> #include <assert.h> #include <string.h> #include "internal.h" OPENSSL_STATIC_ASSERT(16 % sizeof(size_t) == 0, "block cannot be divided into size_t"); void CRYPTO_cfb128_encrypt(const uint8_t *in, uint8_t *out, size_t len, const AES_KEY *key, uint8_t ivec[16], unsigned *num, int enc, block128_f block) { assert(in && out && key && ivec && num); unsigned n = *num; if (enc) { while (n && len) { *(out++) = ivec[n] ^= *(in++); --len; n = (n + 1) % 16; } while (len >= 16) { (*block)(ivec, ivec, key); for (; n < 16; n += sizeof(size_t)) { size_t tmp = load_word_le(ivec + n) ^ load_word_le(in + n); store_word_le(ivec + n, tmp); store_word_le(out + n, tmp); } 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; } else { while (n && len) { uint8_t c; *(out++) = ivec[n] ^ (c = *(in++)); ivec[n] = c; --len; n = (n + 1) % 16; } while (len >= 16) { (*block)(ivec, ivec, key); for (; n < 16; n += sizeof(size_t)) { size_t t = load_word_le(in + n); store_word_le(out + n, load_word_le(ivec + n) ^ t); store_word_le(ivec + n, t); } len -= 16; out += 16; in += 16; n = 0; } if (len) { (*block)(ivec, ivec, key); while (len--) { uint8_t c; out[n] = ivec[n] ^ (c = in[n]); ivec[n] = c; ++n; } } *num = n; return; } } /* 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 uint8_t *in, uint8_t *out, unsigned nbits, const AES_KEY *key, uint8_t ivec[16], int enc, block128_f block) { int n, rem, num; uint8_t 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 OPENSSL_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) { OPENSSL_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 uint8_t *in, uint8_t *out, size_t bits, const AES_KEY *key, uint8_t ivec[16], unsigned *num, int enc, block128_f block) { size_t n; uint8_t c[1], d[1]; assert(in && out && key && ivec && num); assert(*num == 0); 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 AES_KEY *key, unsigned char ivec[16], unsigned *num, int enc, block128_f block) { size_t n; assert(in && out && key && ivec && num); assert(*num == 0); for (n = 0; n < length; ++n) { cfbr_encrypt_block(&in[n], &out[n], 8, key, ivec, enc, block); } }