1 /* SPDX-License-Identifier: BSD-3-Clause 2 * Copyright (c) 2021 Marvell. 3 */ 4 5 #include "roc_api.h" 6 7 #define KEY_WORD_LEN (ROC_CPT_AES_XCBC_KEY_LENGTH / sizeof(uint32_t)) 8 #define KEY_ROUNDS 10 /* (Nr+1)*Nb */ 9 #define KEY_SCHEDULE_LEN ((KEY_ROUNDS + 1) * 4) /* (Nr+1)*Nb words */ 10 11 /* 12 * AES 128 implementation based on NIST FIPS 197 suitable for LittleEndian 13 * https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.197.pdf 14 */ 15 16 /* Sbox from NIST FIPS 197 */ 17 static uint8_t Sbox[] = { 18 0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, 0x30, 0x01, 0x67, 0x2b, 19 0xfe, 0xd7, 0xab, 0x76, 0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, 20 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0, 0xb7, 0xfd, 0x93, 0x26, 21 0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15, 22 0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, 0x07, 0x12, 0x80, 0xe2, 23 0xeb, 0x27, 0xb2, 0x75, 0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, 24 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84, 0x53, 0xd1, 0x00, 0xed, 25 0x20, 0xfc, 0xb1, 0x5b, 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf, 26 0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, 0x45, 0xf9, 0x02, 0x7f, 27 0x50, 0x3c, 0x9f, 0xa8, 0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, 28 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2, 0xcd, 0x0c, 0x13, 0xec, 29 0x5f, 0x97, 0x44, 0x17, 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73, 30 0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, 0x46, 0xee, 0xb8, 0x14, 31 0xde, 0x5e, 0x0b, 0xdb, 0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, 32 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79, 0xe7, 0xc8, 0x37, 0x6d, 33 0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08, 34 0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f, 35 0x4b, 0xbd, 0x8b, 0x8a, 0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, 36 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e, 0xe1, 0xf8, 0x98, 0x11, 37 0x69, 0xd9, 0x8e, 0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf, 38 0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f, 39 0xb0, 0x54, 0xbb, 0x16, 40 }; 41 42 /* Substitute a byte with Sbox[byte]. Do it for a word for 4 bytes */ 43 static uint32_t 44 sub_word(uint32_t word) 45 { 46 word = (Sbox[(word >> 24) & 0xFF] << 24) | 47 (Sbox[(word >> 16) & 0xFF] << 16) | 48 (Sbox[(word >> 8) & 0xFF] << 8) | Sbox[word & 0xFF]; 49 return word; 50 } 51 52 /* Rotate a word by one byte */ 53 static uint32_t 54 rot_word(uint32_t word) 55 { 56 return ((word >> 8) & 0xFFFFFF) | (word << 24); 57 } 58 59 /* 60 * Multiply with power of 2 and polynomial reduce the result using AES 61 * polynomial 62 */ 63 static uint8_t 64 Xtime(uint8_t byte, uint8_t pow) 65 { 66 uint32_t w = byte; 67 68 while (pow) { 69 w = w << 1; 70 if (w >> 8) 71 w ^= 0x11b; 72 pow--; 73 } 74 75 return (uint8_t)w; 76 } 77 78 /* 79 * Multiply a byte with another number such that the result is polynomial 80 * reduced in the GF8 space 81 */ 82 static uint8_t 83 GF8mul(uint8_t byte, uint32_t mp) 84 { 85 uint8_t pow, mul = 0; 86 87 while (mp) { 88 pow = ffs(mp) - 1; 89 mul ^= Xtime(byte, pow); 90 mp ^= (1 << pow); 91 } 92 return mul; 93 } 94 95 static void 96 aes_key_expand(const uint8_t *key, uint32_t *ks) 97 { 98 unsigned int i = 4; 99 uint32_t temp; 100 101 /* Skip key in ks */ 102 memcpy(ks, key, KEY_WORD_LEN * sizeof(uint32_t)); 103 104 while (i < KEY_SCHEDULE_LEN) { 105 temp = ks[i - 1]; 106 if ((i & 0x3) == 0) { 107 temp = rot_word(temp); 108 temp = sub_word(temp); 109 temp ^= (uint32_t)GF8mul(1, 1 << ((i >> 2) - 1)); 110 } 111 ks[i] = ks[i - 4] ^ temp; 112 i++; 113 } 114 } 115 116 /* Shift Rows(columns in state in this implementation) */ 117 static void 118 shift_word(uint8_t *sRc, uint8_t c, int count) 119 { 120 /* rotate across non-consecutive locations */ 121 while (count) { 122 uint8_t t = sRc[c]; 123 124 sRc[c] = sRc[0x4 + c]; 125 sRc[0x4 + c] = sRc[0x8 + c]; 126 sRc[0x8 + c] = sRc[0xc + c]; 127 sRc[0xc + c] = t; 128 count--; 129 } 130 } 131 132 /* Mix Columns(rows in state in this implementation) */ 133 static void 134 mix_columns(uint8_t *sRc) 135 { 136 uint8_t new_st[4]; 137 int i; 138 139 for (i = 0; i < 4; i++) 140 new_st[i] = GF8mul(sRc[i], 0x2) ^ 141 GF8mul(sRc[(i + 1) & 0x3], 0x3) ^ 142 sRc[(i + 2) & 0x3] ^ sRc[(i + 3) & 0x3]; 143 for (i = 0; i < 4; i++) 144 sRc[i] = new_st[i]; 145 } 146 147 static void 148 cipher(uint8_t *in, uint8_t *out, uint32_t *ks) 149 { 150 uint32_t state[KEY_WORD_LEN]; 151 unsigned int i, round; 152 153 memcpy(state, in, sizeof(state)); 154 155 /* AddRoundKey(state, w[0, Nb-1]) // See Sec. 5.1.4 */ 156 for (i = 0; i < KEY_WORD_LEN; i++) 157 state[i] ^= ks[i]; 158 159 for (round = 1; round < KEY_ROUNDS; round++) { 160 /* SubBytes(state) // See Sec. 5.1.1 */ 161 for (i = 0; i < KEY_WORD_LEN; i++) 162 state[i] = sub_word(state[i]); 163 164 /* ShiftRows(state) // See Sec. 5.1.2 */ 165 for (i = 0; i < KEY_WORD_LEN; i++) 166 shift_word((uint8_t *)state, i, i); 167 168 /* MixColumns(state) // See Sec. 5.1.3 */ 169 for (i = 0; i < KEY_WORD_LEN; i++) 170 mix_columns((uint8_t *)&state[i]); 171 172 /* AddRoundKey(state, w[round*Nb, (round+1)*Nb-1]) */ 173 for (i = 0; i < KEY_WORD_LEN; i++) 174 state[i] ^= ks[round * 4 + i]; 175 } 176 177 /* SubBytes(state) */ 178 for (i = 0; i < KEY_WORD_LEN; i++) 179 state[i] = sub_word(state[i]); 180 181 /* ShiftRows(state) */ 182 for (i = 0; i < KEY_WORD_LEN; i++) 183 shift_word((uint8_t *)state, i, i); 184 185 /* AddRoundKey(state, w[Nr*Nb, (Nr+1)*Nb-1]) */ 186 for (i = 0; i < KEY_WORD_LEN; i++) 187 state[i] ^= ks[KEY_ROUNDS * 4 + i]; 188 memcpy(out, state, KEY_WORD_LEN * sizeof(uint32_t)); 189 } 190 191 void 192 roc_aes_xcbc_key_derive(const uint8_t *auth_key, uint8_t *derived_key) 193 { 194 uint32_t aes_ks[KEY_SCHEDULE_LEN] = {0}; 195 uint8_t k1[16] = {[0 ... 15] = 0x01}; 196 uint8_t k2[16] = {[0 ... 15] = 0x02}; 197 uint8_t k3[16] = {[0 ... 15] = 0x03}; 198 199 aes_key_expand(auth_key, aes_ks); 200 201 cipher(k1, derived_key, aes_ks); 202 derived_key += sizeof(k1); 203 204 cipher(k2, derived_key, aes_ks); 205 derived_key += sizeof(k2); 206 207 cipher(k3, derived_key, aes_ks); 208 } 209