/* * aes_cbc.c * * AES Cipher Block Chaining Mode * * David A. McGrew * Cisco Systems, Inc. *//* *	 * Copyright (c) 2001-2006, Cisco Systems, Inc. * All rights reserved. *  * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: *  *   Redistributions of source code must retain the above copyright *   notice, this list of conditions and the following disclaimer. *  *   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. *  *   Neither the name of the Cisco Systems, Inc. nor the names of its *   contributors may be used to endorse or promote products derived *   from this software without specific prior written permission. *  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS 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 * COPYRIGHT HOLDERS OR 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 "aes_cbc.h"#include "alloc.h"debug_module_t mod_aes_cbc = {  0,                 /* debugging is off by default */  "aes cbc"          /* printable module name       */};err_status_taes_cbc_alloc(cipher_t **c, int key_len) {  extern cipher_type_t aes_cbc;  uint8_t *pointer;  int tmp;  debug_print(mod_aes_cbc, 	      "allocating cipher with key length %d", key_len);  if (key_len != 16)    return err_status_bad_param;    /* allocate memory a cipher of type aes_icm */  tmp = (sizeof(aes_cbc_ctx_t) + sizeof(cipher_t));  pointer = (uint8_t*)crypto_alloc(tmp);  if (pointer == NULL)     return err_status_alloc_fail;  /* set pointers */  *c = (cipher_t *)pointer;  (*c)->type = &aes_cbc;  (*c)->state = pointer + sizeof(cipher_t);  /* increment ref_count */  aes_cbc.ref_count++;  /* set key size        */  (*c)->key_len = key_len;  return err_status_ok;  }err_status_taes_cbc_dealloc(cipher_t *c) {  extern cipher_type_t aes_cbc;  /* zeroize entire state*/  octet_string_set_to_zero((uint8_t *)c, 			   sizeof(aes_cbc_ctx_t) + sizeof(cipher_t));  /* free memory */  crypto_free(c);  /* decrement ref_count */  aes_cbc.ref_count--;    return err_status_ok;  }err_status_taes_cbc_context_init(aes_cbc_ctx_t *c, const uint8_t *key, 		     cipher_direction_t dir) {  v128_t tmp_key;  /* set tmp_key (for alignment) */  v128_copy_octet_string(&tmp_key, key);  debug_print(mod_aes_cbc, 	      "key:  %s", v128_hex_string(&tmp_key));   /* expand key for the appropriate direction */  switch (dir) {  case (direction_encrypt):    aes_expand_encryption_key(&tmp_key, c->expanded_key);    break;  case (direction_decrypt):    aes_expand_decryption_key(&tmp_key, c->expanded_key);    break;  default:    return err_status_bad_param;  }  return err_status_ok;}err_status_taes_cbc_set_iv(aes_cbc_ctx_t *c, void *iv) {  int i;/*   v128_t *input = iv; */  uint8_t *input = (uint8_t*) iv;   /* set state and 'previous' block to iv */  for (i=0; i < 16; i++)     c->previous.v8[i] = c->state.v8[i] = input[i];  debug_print(mod_aes_cbc, "setting iv: %s", v128_hex_string(&c->state));   return err_status_ok;}err_status_taes_cbc_encrypt(aes_cbc_ctx_t *c,		unsigned char *data, 		unsigned int *bytes_in_data) {  int i;  unsigned char *input  = data;   /* pointer to data being read    */  unsigned char *output = data;   /* pointer to data being written */  int bytes_to_encr = *bytes_in_data;  /*   * verify that we're 16-octet aligned   */  if (*bytes_in_data & 0xf)     return err_status_bad_param;  /*   * note that we assume that the initialization vector has already   * been set, e.g. by calling aes_cbc_set_iv()   */  debug_print(mod_aes_cbc, "iv: %s", 	      v128_hex_string(&c->state));    /*   * loop over plaintext blocks, exoring state into plaintext then   * encrypting and writing to output   */  while (bytes_to_encr > 0) {        /* exor plaintext into state */    for (i=0; i < 16; i++)      c->state.v8[i] ^= *input++;    debug_print(mod_aes_cbc, "inblock:  %s", 	      v128_hex_string(&c->state));    aes_encrypt(&c->state, c->expanded_key);    debug_print(mod_aes_cbc, "outblock: %s", 	      v128_hex_string(&c->state));    /* copy ciphertext to output */    for (i=0; i < 16; i++)      *output++ = c->state.v8[i];    bytes_to_encr -= 16;  }  return err_status_ok;}err_status_taes_cbc_decrypt(aes_cbc_ctx_t *c,		unsigned char *data, 		unsigned int *bytes_in_data) {  int i;  v128_t state, previous;  unsigned char *input  = data;   /* pointer to data being read    */  unsigned char *output = data;   /* pointer to data being written */  int bytes_to_encr = *bytes_in_data;  uint8_t tmp;  /*   * verify that we're 16-octet aligned   */  if (*bytes_in_data & 0x0f)    return err_status_bad_param;      /* set 'previous' block to iv*/  for (i=0; i < 16; i++) {    previous.v8[i] = c->previous.v8[i];  }  debug_print(mod_aes_cbc, "iv: %s", 	      v128_hex_string(&previous));    /*   * loop over ciphertext blocks, decrypting then exoring with state   * then writing plaintext to output   */  while (bytes_to_encr > 0) {        /* set state to ciphertext input block */    for (i=0; i < 16; i++) {     state.v8[i] = *input++;    }    debug_print(mod_aes_cbc, "inblock:  %s", 	      v128_hex_string(&state));        /* decrypt state */    aes_decrypt(&state, c->expanded_key);    debug_print(mod_aes_cbc, "outblock: %s", 	      v128_hex_string(&state));    /*      * exor previous ciphertext block out of plaintext, and write new     * plaintext block to output, while copying old ciphertext block     * to the 'previous' block     */    for (i=0; i < 16; i++) {      tmp = *output;      *output++ = state.v8[i] ^ previous.v8[i];      previous.v8[i] = tmp;    }    bytes_to_encr -= 16;  }  return err_status_ok;}err_status_taes_cbc_nist_encrypt(aes_cbc_ctx_t *c,		     unsigned char *data, 		     unsigned int *bytes_in_data) {  int i;  unsigned char *pad_start;   int num_pad_bytes;  err_status_t status;  /*    * determine the number of padding bytes that we need to add -    * this value is always between 1 and 16, inclusive.   */  num_pad_bytes = 16 - (*bytes_in_data & 0xf);  pad_start = data;  pad_start += *bytes_in_data;  *pad_start++ = 0xa0;  for (i=0; i < num_pad_bytes; i++)     *pad_start++ = 0x00;     /*    * increment the data size    */  *bytes_in_data += num_pad_bytes;    /*   * now cbc encrypt the padded data    */  status = aes_cbc_encrypt(c, data, bytes_in_data);  if (status)     return status;  return err_status_ok;}err_status_taes_cbc_nist_decrypt(aes_cbc_ctx_t *c,		     unsigned char *data, 		     unsigned int *bytes_in_data) {  unsigned char *pad_end;  int num_pad_bytes;  err_status_t status;  /*   * cbc decrypt the padded data    */  status = aes_cbc_decrypt(c, data, bytes_in_data);  if (status)     return status;  /*   * determine the number of padding bytes in the decrypted plaintext   * - this value is always between 1 and 16, inclusive.   */  num_pad_bytes = 1;  pad_end = data + (*bytes_in_data - 1);  while (*pad_end != 0xa0) {   /* note: should check padding correctness */    pad_end--;    num_pad_bytes++;  }    /* decrement data size */  *bytes_in_data -= num_pad_bytes;    return err_status_ok;}char aes_cbc_description[] = "aes cipher block chaining (cbc) mode";/* * Test case 0 is derived from FIPS 197 Appendix A; it uses an * all-zero IV, so that the first block encryption matches the test * case in that appendix.  This property provides a check of the base * AES encryption and decryption algorithms; if CBC fails on some * particular platform, then you should print out AES intermediate * data and compare with the detailed info provided in that appendix. * */uint8_t aes_cbc_test_case_0_key[16] = {  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,   0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f};uint8_t aes_cbc_test_case_0_plaintext[64] =  {  0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77,  0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff };uint8_t aes_cbc_test_case_0_ciphertext[80] = {  0x69, 0xc4, 0xe0, 0xd8, 0x6a, 0x7b, 0x04, 0x30,   0xd8, 0xcd, 0xb7, 0x80, 0x70, 0xb4, 0xc5, 0x5a,  0x03, 0x35, 0xed, 0x27, 0x67, 0xf2, 0x6d, 0xf1,   0x64, 0x83, 0x2e, 0x23, 0x44, 0x38, 0x70, 0x8b};uint8_t aes_cbc_test_case_0_iv[16] = {  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};cipher_test_case_t aes_cbc_test_case_0 = {  16,                                    /* octets in key            */  aes_cbc_test_case_0_key,               /* key                      */  aes_cbc_test_case_0_iv,                /* initialization vector    */  16,                                    /* octets in plaintext      */  aes_cbc_test_case_0_plaintext,         /* plaintext                */  32,                                    /* octets in ciphertext     */  aes_cbc_test_case_0_ciphertext,        /* ciphertext               */  NULL                                   /* pointer to next testcase */};/* * this test case is taken directly from Appendix F.2 of NIST Special * Publication SP 800-38A */uint8_t aes_cbc_test_case_1_key[16] = {  0x2b, 0x7e, 0x15, 0x16, 0x28, 0xae, 0xd2, 0xa6,  0xab, 0xf7, 0x15, 0x88, 0x09, 0xcf, 0x4f, 0x3c,};uint8_t aes_cbc_test_case_1_plaintext[64] =  {  0x6b, 0xc1, 0xbe, 0xe2, 0x2e, 0x40, 0x9f, 0x96,   0xe9, 0x3d, 0x7e, 0x11, 0x73, 0x93, 0x17, 0x2a,  0xae, 0x2d, 0x8a, 0x57, 0x1e, 0x03, 0xac, 0x9c,   0x9e, 0xb7, 0x6f, 0xac, 0x45, 0xaf, 0x8e, 0x51,  0x30, 0xc8, 0x1c, 0x46, 0xa3, 0x5c, 0xe4, 0x11,  0xe5, 0xfb, 0xc1, 0x19, 0x1a, 0x0a, 0x52, 0xef,  0xf6, 0x9f, 0x24, 0x45, 0xdf, 0x4f, 0x9b, 0x17,   0xad, 0x2b, 0x41, 0x7b, 0xe6, 0x6c, 0x37, 0x10};uint8_t aes_cbc_test_case_1_ciphertext[80] = {  0x76, 0x49, 0xab, 0xac, 0x81, 0x19, 0xb2, 0x46,  0xce, 0xe9, 0x8e, 0x9b, 0x12, 0xe9, 0x19, 0x7d,  0x50, 0x86, 0xcb, 0x9b, 0x50, 0x72, 0x19, 0xee,  0x95, 0xdb, 0x11, 0x3a, 0x91, 0x76, 0x78, 0xb2,  0x73, 0xbe, 0xd6, 0xb8, 0xe3, 0xc1, 0x74, 0x3b,  0x71, 0x16, 0xe6, 0x9e, 0x22, 0x22, 0x95, 0x16,   0x3f, 0xf1, 0xca, 0xa1, 0x68, 0x1f, 0xac, 0x09,   0x12, 0x0e, 0xca, 0x30, 0x75, 0x86, 0xe1, 0xa7,  0x39, 0x34, 0x07, 0x03, 0x36, 0xd0, 0x77, 0x99,   0xe0, 0xc4, 0x2f, 0xdd, 0xa8, 0xdf, 0x4c, 0xa3};uint8_t aes_cbc_test_case_1_iv[16] = {  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,   0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f};cipher_test_case_t aes_cbc_test_case_1 = {  16,                                    /* octets in key            */  aes_cbc_test_case_1_key,               /* key                      */  aes_cbc_test_case_1_iv,                /* initialization vector    */  64,                                    /* octets in plaintext      */  aes_cbc_test_case_1_plaintext,         /* plaintext                */  80,                                    /* octets in ciphertext     */  aes_cbc_test_case_1_ciphertext,        /* ciphertext               */  &aes_cbc_test_case_0                    /* pointer to next testcase */};cipher_type_t aes_cbc = {  (cipher_alloc_func_t)          aes_cbc_alloc,  (cipher_dealloc_func_t)        aes_cbc_dealloc,    (cipher_init_func_t)           aes_cbc_context_init,  (cipher_encrypt_func_t)        aes_cbc_nist_encrypt,  (cipher_decrypt_func_t)        aes_cbc_nist_decrypt,  (cipher_set_iv_func_t)         aes_cbc_set_iv,  (char *)                       aes_cbc_description,  (int)                          0,   /* instance count */  (cipher_test_case_t *)        &aes_cbc_test_case_0,  (debug_module_t *)            &mod_aes_cbc};