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1 | office | 1 | /** |
2 | * @file OTPCalculator.c |
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3 | * @author Ambroz Bizjak <ambrop7@gmail.com> |
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4 | * |
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5 | * @section LICENSE |
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6 | * |
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7 | * Redistribution and use in source and binary forms, with or without |
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8 | * modification, are permitted provided that the following conditions are met: |
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9 | * 1. Redistributions of source code must retain the above copyright |
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10 | * notice, this list of conditions and the following disclaimer. |
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11 | * 2. Redistributions in binary form must reproduce the above copyright |
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12 | * notice, this list of conditions and the following disclaimer in the |
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13 | * documentation and/or other materials provided with the distribution. |
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14 | * 3. Neither the name of the author nor the |
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15 | * names of its contributors may be used to endorse or promote products |
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16 | * derived from this software without specific prior written permission. |
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17 | * |
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18 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND |
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19 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED |
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20 | * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
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21 | * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY |
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22 | * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES |
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23 | * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
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24 | * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND |
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25 | * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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26 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
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27 | * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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28 | */ |
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29 | |||
30 | #include <limits.h> |
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31 | |||
32 | #include <misc/balloc.h> |
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33 | |||
34 | #include <security/OTPCalculator.h> |
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35 | |||
36 | int OTPCalculator_Init (OTPCalculator *calc, int num_otps, int cipher) |
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37 | { |
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38 | ASSERT(num_otps >= 0) |
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39 | ASSERT(BEncryption_cipher_valid(cipher)) |
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40 | |||
41 | // init arguments |
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42 | calc->num_otps = num_otps; |
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43 | calc->cipher = cipher; |
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44 | |||
45 | // remember block size |
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46 | calc->block_size = BEncryption_cipher_block_size(calc->cipher); |
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47 | |||
48 | // calculate number of blocks |
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49 | if (calc->num_otps > SIZE_MAX / sizeof(otp_t)) { |
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50 | goto fail0; |
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51 | } |
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52 | calc->num_blocks = bdivide_up(calc->num_otps * sizeof(otp_t), calc->block_size); |
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53 | |||
54 | // allocate buffer |
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55 | if (!(calc->data = (otp_t *)BAllocArray(calc->num_blocks, calc->block_size))) { |
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56 | goto fail0; |
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57 | } |
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58 | |||
59 | // init debug object |
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60 | DebugObject_Init(&calc->d_obj); |
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61 | |||
62 | return 1; |
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63 | |||
64 | fail0: |
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65 | return 0; |
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66 | } |
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67 | |||
68 | void OTPCalculator_Free (OTPCalculator *calc) |
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69 | { |
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70 | // free debug object |
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71 | DebugObject_Free(&calc->d_obj); |
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72 | |||
73 | // free buffer |
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74 | BFree(calc->data); |
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75 | } |
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76 | |||
77 | otp_t * OTPCalculator_Generate (OTPCalculator *calc, uint8_t *key, uint8_t *iv, int shuffle) |
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78 | { |
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79 | ASSERT(shuffle == 0 || shuffle == 1) |
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80 | |||
81 | // copy IV so it can be updated |
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82 | uint8_t iv_work[BENCRYPTION_MAX_BLOCK_SIZE]; |
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83 | memcpy(iv_work, iv, calc->block_size); |
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84 | |||
85 | // create zero block |
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86 | uint8_t zero[BENCRYPTION_MAX_BLOCK_SIZE]; |
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87 | memset(zero, 0, calc->block_size); |
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88 | |||
89 | // init encryptor |
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90 | BEncryption encryptor; |
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91 | BEncryption_Init(&encryptor, BENCRYPTION_MODE_ENCRYPT, calc->cipher, key); |
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92 | |||
93 | // encrypt zero blocks |
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94 | for (size_t i = 0; i < calc->num_blocks; i++) { |
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95 | BEncryption_Encrypt(&encryptor, zero, (uint8_t *)calc->data + i * calc->block_size, calc->block_size, iv_work); |
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96 | } |
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97 | |||
98 | // free encryptor |
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99 | BEncryption_Free(&encryptor); |
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100 | |||
101 | // shuffle if requested |
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102 | if (shuffle) { |
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103 | int i = 0; |
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104 | while (i < calc->num_otps) { |
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105 | uint16_t ints[256]; |
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106 | BRandom_randomize((uint8_t *)ints, sizeof(ints)); |
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107 | for (int j = 0; j < 256 && i < calc->num_otps; j++) { |
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108 | int newIndex = i + (ints[j] % (calc->num_otps - i)); |
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109 | otp_t temp = calc->data[i]; |
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110 | calc->data[i] = calc->data[newIndex]; |
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111 | calc->data[newIndex] = temp; |
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112 | i++; |
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113 | } |
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114 | } |
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115 | } |
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116 | |||
117 | return calc->data; |
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118 | } |