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1.1 misho 1: /* 2: * Copyright (C) 2013 Tobias Brunner 3: * HSR Hochschule fuer Technik Rapperswil 4: * 5: * This program is free software; you can redistribute it and/or modify it 6: * under the terms of the GNU General Public License as published by the 7: * Free Software Foundation; either version 2 of the License, or (at your 8: * option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>. 9: * 10: * This program is distributed in the hope that it will be useful, but 11: * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 12: * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 13: * for more details. 14: */ 15: 16: #include "rc2_crypter.h" 17: 18: typedef struct private_rc2_crypter_t private_rc2_crypter_t; 19: 20: #define RC2_BLOCK_SIZE 8 21: 22: #define ROL16(x, k) ({ uint16_t _x = (x); (_x << (k)) | (_x >> (16 - (k))); }) 23: #define ROR16(x, k) ({ uint16_t _x = (x); (_x >> (k)) | (_x << (16 - (k))); }) 24: 25: #define GET16(x) ({ u_char *_x = (x); (uint16_t)_x[0] | ((uint16_t)_x[1] << 8); }) 26: #define PUT16(x, v) ({ u_char *_x = (x); uint16_t _v = (v); _x[0] = _v, _x[1] = _v >> 8; }) 27: 28: /** 29: * Private data of rc2_crypter_t 30: */ 31: struct private_rc2_crypter_t { 32: 33: /** 34: * Public interface 35: */ 36: rc2_crypter_t public; 37: 38: /** 39: * The expanded key in 16-bit words 40: */ 41: uint16_t K[64]; 42: 43: /** 44: * Key size in bytes 45: */ 46: size_t T; 47: 48: /** 49: * Effective key size in bits 50: */ 51: size_t T1; 52: }; 53: 54: /** 55: * PITABLE 56: */ 57: static const u_char PITABLE[256] = 58: { 59: 0xd9, 0x78, 0xf9, 0xc4, 0x19, 0xdd, 0xb5, 0xed, 60: 0x28, 0xe9, 0xfd, 0x79, 0x4a, 0xa0, 0xd8, 0x9d, 61: 0xc6, 0x7e, 0x37, 0x83, 0x2b, 0x76, 0x53, 0x8e, 62: 0x62, 0x4c, 0x64, 0x88, 0x44, 0x8b, 0xfb, 0xa2, 63: 0x17, 0x9a, 0x59, 0xf5, 0x87, 0xb3, 0x4f, 0x13, 64: 0x61, 0x45, 0x6d, 0x8d, 0x09, 0x81, 0x7d, 0x32, 65: 0xbd, 0x8f, 0x40, 0xeb, 0x86, 0xb7, 0x7b, 0x0b, 66: 0xf0, 0x95, 0x21, 0x22, 0x5c, 0x6b, 0x4e, 0x82, 67: 0x54, 0xd6, 0x65, 0x93, 0xce, 0x60, 0xb2, 0x1c, 68: 0x73, 0x56, 0xc0, 0x14, 0xa7, 0x8c, 0xf1, 0xdc, 69: 0x12, 0x75, 0xca, 0x1f, 0x3b, 0xbe, 0xe4, 0xd1, 70: 0x42, 0x3d, 0xd4, 0x30, 0xa3, 0x3c, 0xb6, 0x26, 71: 0x6f, 0xbf, 0x0e, 0xda, 0x46, 0x69, 0x07, 0x57, 72: 0x27, 0xf2, 0x1d, 0x9b, 0xbc, 0x94, 0x43, 0x03, 73: 0xf8, 0x11, 0xc7, 0xf6, 0x90, 0xef, 0x3e, 0xe7, 74: 0x06, 0xc3, 0xd5, 0x2f, 0xc8, 0x66, 0x1e, 0xd7, 75: 0x08, 0xe8, 0xea, 0xde, 0x80, 0x52, 0xee, 0xf7, 76: 0x84, 0xaa, 0x72, 0xac, 0x35, 0x4d, 0x6a, 0x2a, 77: 0x96, 0x1a, 0xd2, 0x71, 0x5a, 0x15, 0x49, 0x74, 78: 0x4b, 0x9f, 0xd0, 0x5e, 0x04, 0x18, 0xa4, 0xec, 79: 0xc2, 0xe0, 0x41, 0x6e, 0x0f, 0x51, 0xcb, 0xcc, 80: 0x24, 0x91, 0xaf, 0x50, 0xa1, 0xf4, 0x70, 0x39, 81: 0x99, 0x7c, 0x3a, 0x85, 0x23, 0xb8, 0xb4, 0x7a, 82: 0xfc, 0x02, 0x36, 0x5b, 0x25, 0x55, 0x97, 0x31, 83: 0x2d, 0x5d, 0xfa, 0x98, 0xe3, 0x8a, 0x92, 0xae, 84: 0x05, 0xdf, 0x29, 0x10, 0x67, 0x6c, 0xba, 0xc9, 85: 0xd3, 0x00, 0xe6, 0xcf, 0xe1, 0x9e, 0xa8, 0x2c, 86: 0x63, 0x16, 0x01, 0x3f, 0x58, 0xe2, 0x89, 0xa9, 87: 0x0d, 0x38, 0x34, 0x1b, 0xab, 0x33, 0xff, 0xb0, 88: 0xbb, 0x48, 0x0c, 0x5f, 0xb9, 0xb1, 0xcd, 0x2e, 89: 0xc5, 0xf3, 0xdb, 0x47, 0xe5, 0xa5, 0x9c, 0x77, 90: 0x0a, 0xa6, 0x20, 0x68, 0xfe, 0x7f, 0xc1, 0xad, 91: }; 92: 93: /** 94: * Encrypt a single block of data 95: */ 96: static void encrypt_block(private_rc2_crypter_t *this, u_char R[]) 97: { 98: register uint16_t R0, R1, R2, R3, *Kj; 99: int rounds = 3, mix = 5; 100: 101: R0 = GET16(R); 102: R1 = GET16(R + 2); 103: R2 = GET16(R + 4); 104: R3 = GET16(R + 6); 105: Kj = &this->K[0]; 106: 107: /* 5 mix, mash, 6 mix, mash, 5 mix */ 108: while (TRUE) 109: { 110: /* mix */ 111: R0 = ROL16(R0 + *(Kj++) + (R3 & R2) + (~R3 & R1), 1); 112: R1 = ROL16(R1 + *(Kj++) + (R0 & R3) + (~R0 & R2), 2); 113: R2 = ROL16(R2 + *(Kj++) + (R1 & R0) + (~R1 & R3), 3); 114: R3 = ROL16(R3 + *(Kj++) + (R2 & R1) + (~R2 & R0), 5); 115: 116: if (--mix == 0) 117: { 118: if (--rounds == 0) 119: { 120: break; 121: } 122: mix = (rounds == 2) ? 6 : 5; 123: /* mash */ 124: R0 += this->K[R3 & 63]; 125: R1 += this->K[R0 & 63]; 126: R2 += this->K[R1 & 63]; 127: R3 += this->K[R2 & 63]; 128: } 129: } 130: 131: PUT16(R, R0); 132: PUT16(R + 2, R1); 133: PUT16(R + 4, R2); 134: PUT16(R + 6, R3); 135: } 136: 137: /** 138: * Decrypt a single block of data. 139: */ 140: static void decrypt_block(private_rc2_crypter_t *this, u_char R[]) 141: { 142: register uint16_t R0, R1, R2, R3, *Kj; 143: int rounds = 3, mix = 5; 144: 145: R0 = GET16(R); 146: R1 = GET16(R + 2); 147: R2 = GET16(R + 4); 148: R3 = GET16(R + 6); 149: Kj = &this->K[63]; 150: 151: /* 5 r-mix, r-mash, 6 r-mix, r-mash, 5 r-mix */ 152: while (TRUE) 153: { 154: /* r-mix */ 155: R3 = ROR16(R3, 5); 156: R3 = R3 - *(Kj--) - (R2 & R1) - (~R2 & R0); 157: R2 = ROR16(R2, 3); 158: R2 = R2 - *(Kj--) - (R1 & R0) - (~R1 & R3); 159: R1 = ROR16(R1, 2); 160: R1 = R1 - *(Kj--) - (R0 & R3) - (~R0 & R2); 161: R0 = ROR16(R0, 1); 162: R0 = R0 - *(Kj--) - (R3 & R2) - (~R3 & R1); 163: 164: if (--mix == 0) 165: { 166: if (--rounds == 0) 167: { 168: break; 169: } 170: mix = (rounds == 2) ? 6 : 5; 171: /* r-mash */ 172: R3 -= this->K[R2 & 63]; 173: R2 -= this->K[R1 & 63]; 174: R1 -= this->K[R0 & 63]; 175: R0 -= this->K[R3 & 63]; 176: } 177: } 178: 179: PUT16(R, R0); 180: PUT16(R + 2, R1); 181: PUT16(R + 4, R2); 182: PUT16(R + 6, R3); 183: } 184: 185: METHOD(crypter_t, decrypt, bool, 186: private_rc2_crypter_t *this, chunk_t data, chunk_t iv, chunk_t *decrypted) 187: { 188: uint8_t *in, *out, *prev; 189: 190: if (data.len % RC2_BLOCK_SIZE || iv.len != RC2_BLOCK_SIZE) 191: { 192: return FALSE; 193: } 194: 195: in = data.ptr + data.len - RC2_BLOCK_SIZE; 196: out = data.ptr; 197: if (decrypted) 198: { 199: *decrypted = chunk_alloc(data.len); 200: out = decrypted->ptr; 201: } 202: out += data.len - RC2_BLOCK_SIZE; 203: 204: prev = in; 205: for (; in >= data.ptr; in -= RC2_BLOCK_SIZE, out -= RC2_BLOCK_SIZE) 206: { 207: if (decrypted) 208: { 209: memcpy(out, in, RC2_BLOCK_SIZE); 210: } 211: decrypt_block(this, out); 212: prev -= RC2_BLOCK_SIZE; 213: if (prev < data.ptr) 214: { 215: prev = iv.ptr; 216: } 217: memxor(out, prev, RC2_BLOCK_SIZE); 218: } 219: return TRUE; 220: } 221: 222: METHOD(crypter_t, encrypt, bool, 223: private_rc2_crypter_t *this, chunk_t data, chunk_t iv, chunk_t *encrypted) 224: { 225: uint8_t *in, *out, *end, *prev; 226: 227: if (data.len % RC2_BLOCK_SIZE || iv.len != RC2_BLOCK_SIZE) 228: { 229: return FALSE; 230: } 231: 232: in = data.ptr; 233: end = data.ptr + data.len; 234: out = data.ptr; 235: if (encrypted) 236: { 237: *encrypted = chunk_alloc(data.len); 238: out = encrypted->ptr; 239: } 240: 241: prev = iv.ptr; 242: for (; in < end; in += RC2_BLOCK_SIZE, out += RC2_BLOCK_SIZE) 243: { 244: if (encrypted) 245: { 246: memcpy(out, in, RC2_BLOCK_SIZE); 247: } 248: memxor(out, prev, RC2_BLOCK_SIZE); 249: encrypt_block(this, out); 250: prev = out; 251: } 252: return TRUE; 253: } 254: 255: METHOD(crypter_t, get_block_size, size_t, 256: private_rc2_crypter_t *this) 257: { 258: return RC2_BLOCK_SIZE; 259: } 260: 261: METHOD(crypter_t, get_iv_size, size_t, 262: private_rc2_crypter_t *this) 263: { 264: return RC2_BLOCK_SIZE; 265: } 266: 267: METHOD(crypter_t, get_key_size, size_t, 268: private_rc2_crypter_t *this) 269: { 270: return this->T; 271: } 272: 273: METHOD(crypter_t, set_key, bool, 274: private_rc2_crypter_t *this, chunk_t key) 275: { 276: uint8_t L[128], T8, TM, idx; 277: int i; 278: 279: if (key.len != this->T) 280: { 281: return FALSE; 282: } 283: for (i = 0; i < key.len; i++) 284: { 285: L[i] = key.ptr[i]; 286: } 287: for (; i < 128; i++) 288: { 289: idx = L[i-1] + L[i-key.len]; 290: L[i] = PITABLE[idx]; 291: } 292: T8 = (this->T1 + 7) / 8; 293: TM = ~(0xff << (8 - (8*T8 - this->T1))); 294: L[128-T8] = PITABLE[L[128-T8] & TM]; 295: for (i = 127-T8; i >= 0; i--) 296: { 297: idx = L[i+1] ^ L[i+T8]; 298: L[i] = PITABLE[idx]; 299: } 300: for (i = 0; i < 64; i++) 301: { 302: this->K[i] = GET16(&L[i << 1]); 303: } 304: memwipe(L, sizeof(L)); 305: return TRUE; 306: } 307: 308: METHOD(crypter_t, destroy, void, 309: private_rc2_crypter_t *this) 310: { 311: memwipe(this->K, sizeof(this->K)); 312: free(this); 313: } 314: 315: /* 316: * Described in header 317: */ 318: rc2_crypter_t *rc2_crypter_create(encryption_algorithm_t algo, size_t key_size) 319: { 320: private_rc2_crypter_t *this; 321: size_t effective; 322: 323: if (algo != ENCR_RC2_CBC) 324: { 325: return NULL; 326: } 327: key_size = max(1, key_size); 328: effective = RC2_EFFECTIVE_KEY_LEN(key_size); 329: key_size = min(128, RC2_KEY_LEN(key_size)); 330: effective = max(1, min(1024, effective ?: key_size * 8)); 331: 332: INIT(this, 333: .public = { 334: .crypter = { 335: .encrypt = _encrypt, 336: .decrypt = _decrypt, 337: .get_block_size = _get_block_size, 338: .get_iv_size = _get_iv_size, 339: .get_key_size = _get_key_size, 340: .set_key = _set_key, 341: .destroy = _destroy, 342: }, 343: }, 344: .T = key_size, 345: .T1 = effective, 346: ); 347: 348: return &this->public; 349: }