git.m6w6.name Git - awesomized/libmemcached/blob - src/libhashkit/aes.cc

   1 /*
   2     +--------------------------------------------------------------------+
   3     | libmemcached - C/C++ Client Library for memcached                  |
   4     +--------------------------------------------------------------------+
   5     | Redistribution and use in source and binary forms, with or without |
   6     | modification, are permitted under the terms of the BSD license.    |
   7     | You should have received a copy of the license in a bundled file   |
   8     | named LICENSE; in case you did not receive a copy you can review   |
   9     | the terms online at: https://opensource.org/licenses/BSD-3-Clause  |
  10     +--------------------------------------------------------------------+
  11     | Copyright (c) 2006-2014 Brian Aker   https://datadifferential.com/ |
  12     | Copyright (c) 2020-2021 Michael Wallner        https://awesome.co/ |
  13     +--------------------------------------------------------------------+
  14 */
  15
  16 #include "libhashkit/common.h"
  17
  18 #include "libhashkit/rijndael.hpp"
  19
  20 #include <cstring>
  21
  22 #define AES_KEY_LENGTH 256 /* 128, 192, 256 */
  23 #define AES_BLOCK_SIZE 16
  24
  25 enum encrypt_t { AES_ENCRYPT, AES_DECRYPT };
  26
  27 struct _key_t {
  28   int nr;
  29   uint32_t rk[4 * (AES_MAXNR + 1)];
  30 };
  31
  32 struct aes_key_t {
  33   _key_t encode_key;
  34   _key_t decode_key;
  35 };
  36
  37 aes_key_t *aes_create_key(const char *key, const size_t key_length) {
  38   aes_key_t *_aes_key = (aes_key_t *) (calloc(1, sizeof(aes_key_t)));
  39   if (_aes_key) {
  40     uint8_t rkey[AES_KEY_LENGTH / 8];
  41     uint8_t *rkey_end = rkey + AES_KEY_LENGTH / 8;
  42     const char *key_end = key + key_length;
  43
  44     memset(rkey, 0, sizeof(rkey)); /* Set initial key  */
  45
  46     uint8_t *ptr = rkey;
  47     const char *sptr = key;
  48     for (; sptr < key_end; ptr++, sptr++) {
  49       if (ptr == rkey_end) {
  50         ptr = rkey; /*  Just loop over tmp_key until we used all key */
  51       }
  52       *ptr ^= (uint8_t)(*sptr);
  53     }
  54
  55     _aes_key->decode_key.nr = rijndaelKeySetupDec(_aes_key->decode_key.rk, rkey, AES_KEY_LENGTH);
  56     _aes_key->encode_key.nr = rijndaelKeySetupEnc(_aes_key->encode_key.rk, rkey, AES_KEY_LENGTH);
  57   }
  58
  59   return _aes_key;
  60 }
  61
  62 aes_key_t *aes_clone_key(aes_key_t *_aes_key) {
  63   if (_aes_key == NULL) {
  64     return NULL;
  65   }
  66
  67   aes_key_t *_aes_clone_key = (aes_key_t *) (calloc(1, sizeof(aes_key_t)));
  68   if (_aes_clone_key) {
  69     memcpy(_aes_clone_key, _aes_key, sizeof(aes_key_t));
  70   }
  71
  72   return _aes_clone_key;
  73 }
  74
  75 hashkit_string_st *aes_encrypt(aes_key_t *_aes_key, const char *source, size_t source_length) {
  76   if (_aes_key == NULL) {
  77     return NULL;
  78   }
  79
  80   size_t num_blocks = source_length / AES_BLOCK_SIZE;
  81
  82   hashkit_string_st *destination = hashkit_string_create(source_length);
  83   if (destination) {
  84     char *dest = hashkit_string_c_str_mutable(destination);
  85
  86     for (size_t x = num_blocks; x > 0; x--) /* Encode complete blocks */ {
  87       rijndaelEncrypt(_aes_key->encode_key.rk, _aes_key->encode_key.nr, (const uint8_t *) (source),
  88                       (uint8_t *) (dest));
  89       source += AES_BLOCK_SIZE;
  90       dest += AES_BLOCK_SIZE;
  91     }
  92
  93     uint8_t block[AES_BLOCK_SIZE];
  94     char pad_len = AES_BLOCK_SIZE - (source_length - AES_BLOCK_SIZE * num_blocks);
  95     memcpy(block, source, 16 - pad_len);
  96     memset(block + AES_BLOCK_SIZE - pad_len, pad_len, pad_len);
  97     rijndaelEncrypt(_aes_key->encode_key.rk, _aes_key->encode_key.nr, block, (uint8_t *) (dest));
  98     hashkit_string_set_length(destination, AES_BLOCK_SIZE * (num_blocks + 1));
  99   }
 100
 101   return destination;
 102 }
 103
 104 hashkit_string_st *aes_decrypt(aes_key_t *_aes_key, const char *source, size_t source_length) {
 105   if (_aes_key == NULL) {
 106     return NULL;
 107   }
 108
 109   size_t num_blocks = source_length / AES_BLOCK_SIZE;
 110   if ((source_length != num_blocks * AES_BLOCK_SIZE) or num_blocks == 0) {
 111     return NULL;
 112   }
 113
 114   hashkit_string_st *destination = hashkit_string_create(source_length);
 115   if (destination) {
 116     char *dest = hashkit_string_c_str_mutable(destination);
 117
 118     for (size_t x = num_blocks - 1; x > 0; x--) {
 119       rijndaelDecrypt(_aes_key->decode_key.rk, _aes_key->decode_key.nr, (const uint8_t *) (source),
 120                       (uint8_t *) (dest));
 121       source += AES_BLOCK_SIZE;
 122       dest += AES_BLOCK_SIZE;
 123     }
 124
 125     uint8_t block[AES_BLOCK_SIZE];
 126     rijndaelDecrypt(_aes_key->decode_key.rk, _aes_key->decode_key.nr, (const uint8_t *) (source),
 127                     block);
 128     /* Use last char in the block as size */
 129     unsigned int pad_len = (unsigned int) (unsigned char) (block[AES_BLOCK_SIZE - 1]);
 130     if (pad_len > AES_BLOCK_SIZE) {
 131       hashkit_string_free(destination);
 132       return NULL;
 133     }
 134
 135     /* We could also check whole padding but we do not really need this */
 136
 137     memcpy(dest, block, AES_BLOCK_SIZE - pad_len);
 138     hashkit_string_set_length(destination, AES_BLOCK_SIZE * num_blocks - pad_len);
 139   }
 140
 141   return destination;
 142 }