/* ==================================================================== * 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_grpc/type_check.h> #include <assert.h> #include <string.h> #include "internal.h" #include "../../internal.h" // NOTE: the IV/counter CTR mode is big-endian. The code itself // is endian-neutral. // increment counter (128-bit int) by 1 static void ctr128_inc(uint8_t *counter) { uint32_t n = 16, c = 1; do { --n; c += counter[n]; counter[n] = (uint8_t) c; c >>= 8; } while (n); } OPENSSL_STATIC_ASSERT(16 % sizeof(crypto_word_t) == 0, "block cannot be divided into crypto_word_t"); // The input encrypted as though 128bit counter mode is being used. The extra // state information to record how much of the 128bit block we have used is // contained in *num, and the encrypted counter is kept in ecount_buf. Both // *num and ecount_buf must be initialised with zeros before the first call to // CRYPTO_ctr128_encrypt(). // // This algorithm assumes that the counter is in the x lower bits of the IV // (ivec), and that the application has full control over overflow and the rest // of the IV. This implementation takes NO responsibility for checking that // the counter doesn't overflow into the rest of the IV when incremented. void CRYPTO_ctr128_encrypt(const uint8_t *in, uint8_t *out, size_t len, const AES_KEY *key, uint8_t ivec[16], uint8_t ecount_buf[16], unsigned int *num, block128_f block) { unsigned int n; assert(key && ecount_buf && num); assert(len == 0 || (in && out)); assert(*num < 16); n = *num; while (n && len) { *(out++) = *(in++) ^ ecount_buf[n]; --len; n = (n + 1) % 16; } while (len >= 16) { (*block)(ivec, ecount_buf, key); ctr128_inc(ivec); for (n = 0; n < 16; n += sizeof(crypto_word_t)) { CRYPTO_store_word_le(out + n, CRYPTO_load_word_le(in + n) ^ CRYPTO_load_word_le(ecount_buf + n)); } len -= 16; out += 16; in += 16; n = 0; } if (len) { (*block)(ivec, ecount_buf, key); ctr128_inc(ivec); while (len--) { out[n] = in[n] ^ ecount_buf[n]; ++n; } } *num = n; } // increment upper 96 bits of 128-bit counter by 1 static void ctr96_inc(uint8_t *counter) { uint32_t n = 12, c = 1; do { --n; c += counter[n]; counter[n] = (uint8_t) c; c >>= 8; } while (n); } void CRYPTO_ctr128_encrypt_ctr32(const uint8_t *in, uint8_t *out, size_t len, const AES_KEY *key, uint8_t ivec[16], uint8_t ecount_buf[16], unsigned int *num, ctr128_f func) { unsigned int n, ctr32; assert(key && ecount_buf && num); assert(len == 0 || (in && out)); assert(*num < 16); n = *num; while (n && len) { *(out++) = *(in++) ^ ecount_buf[n]; --len; n = (n + 1) % 16; } ctr32 = CRYPTO_load_u32_be(ivec + 12); while (len >= 16) { size_t blocks = len / 16; // 1<<28 is just a not-so-small yet not-so-large number... // Below condition is practically never met, but it has to // be checked for code correctness. if (sizeof(size_t) > sizeof(unsigned int) && blocks > (1U << 28)) { blocks = (1U << 28); } // As (*func) operates on 32-bit counter, caller // has to handle overflow. 'if' below detects the // overflow, which is then handled by limiting the // amount of blocks to the exact overflow point... ctr32 += (uint32_t)blocks; if (ctr32 < blocks) { blocks -= ctr32; ctr32 = 0; } (*func)(in, out, blocks, key, ivec); // (*func) does not update ivec, caller does: CRYPTO_store_u32_be(ivec + 12, ctr32); // ... overflow was detected, propogate carry. if (ctr32 == 0) { ctr96_inc(ivec); } blocks *= 16; len -= blocks; out += blocks; in += blocks; } if (len) { OPENSSL_memset(ecount_buf, 0, 16); (*func)(ecount_buf, ecount_buf, 1, key, ivec); ++ctr32; CRYPTO_store_u32_be(ivec + 12, ctr32); if (ctr32 == 0) { ctr96_inc(ivec); } while (len--) { out[n] = in[n] ^ ecount_buf[n]; ++n; } } *num = n; }