| 1 | /************************************************************************** |
| 2 | * Unix-like crypt(3) Algorithm for Password Encryption |
| 3 | * |
| 4 | * File : crypt3.c |
| 5 | * Purpose : Provides crypt(3) functionality to ANSI C compilers |
| 6 | * without a need for the crypt library. |
| 7 | * Author : Michael Dipperstein |
| 8 | * Date : November 3, 1998 |
| 9 | * |
| 10 | *************************************************************************** |
| 11 | * The source in this file is heavily borrowed from the crypt3.c file |
| 12 | * found on several ftp sites on the Internet. The original source |
| 13 | * claimed to be BSD, but was not distributed with any BSD license or |
| 14 | * copyright claims. I am releasing the source that I have provided into |
| 15 | * public domain without any restrictions, warranties, or copyright |
| 16 | * claims of my own. |
| 17 | * |
| 18 | * The code below has been cleaned and compiles correctly under, gcc, |
| 19 | * lcc, and Borland's bcc C compilers. A bug involving the left and |
| 20 | * right halves of the encrypted data block in the widely published |
| 21 | * crypt3.c source has been fixed by this version. All implicit register |
| 22 | * declarations have been removed, because they generated suboptimal code. |
| 23 | * All constant data has been explicitly declared as const and all |
| 24 | * declarations have been given a minimal scope, because I'm paranoid. |
| 25 | * |
| 26 | * Caution: crypt() returns a pointer to static data. I left it this way |
| 27 | * to maintain backward compatibility. The downside is that |
| 28 | * successive calls will cause previous results to be lost. |
| 29 | * This can easily be changed with only minor modifications to |
| 30 | * the function crypt(). |
| 31 | **************************************************************************/ |
| 32 | |
| 33 | /* Initial permutation */ |
| 34 | static const char IP[] = |
| 35 | { |
| 36 | 58, 50, 42, 34, 26, 18, 10, 2, |
| 37 | 60, 52, 44, 36, 28, 20, 12, 4, |
| 38 | 62, 54, 46, 38, 30, 22, 14, 6, |
| 39 | 64, 56, 48, 40, 32, 24, 16, 8, |
| 40 | 57, 49, 41, 33, 25, 17, 9, 1, |
| 41 | 59, 51, 43, 35, 27, 19, 11, 3, |
| 42 | 61, 53, 45, 37, 29, 21, 13, 5, |
| 43 | 63, 55, 47, 39, 31, 23, 15, 7, |
| 44 | }; |
| 45 | |
| 46 | /* Final permutation, FP = IP^(-1) */ |
| 47 | static const char FP[] = { |
| 48 | 40, 8, 48, 16, 56, 24, 64, 32, |
| 49 | 39, 7, 47, 15, 55, 23, 63, 31, |
| 50 | 38, 6, 46, 14, 54, 22, 62, 30, |
| 51 | 37, 5, 45, 13, 53, 21, 61, 29, |
| 52 | 36, 4, 44, 12, 52, 20, 60, 28, |
| 53 | 35, 3, 43, 11, 51, 19, 59, 27, |
| 54 | 34, 2, 42, 10, 50, 18, 58, 26, |
| 55 | 33, 1, 41, 9, 49, 17, 57, 25, |
| 56 | }; |
| 57 | |
| 58 | /************************************************************************** |
| 59 | * Permuted-choice 1 from the key bits to yield C and D. |
| 60 | * Note that bits 8,16... are left out: |
| 61 | * They are intended for a parity check. |
| 62 | **************************************************************************/ |
| 63 | static const char PC1_C[] = |
| 64 | { |
| 65 | 57, 49, 41, 33, 25, 17, 9, |
| 66 | 1, 58, 50, 42, 34, 26, 18, |
| 67 | 10, 2, 59, 51, 43, 35, 27, |
| 68 | 19, 11, 3, 60, 52, 44, 36, |
| 69 | }; |
| 70 | |
| 71 | static const char PC1_D[] = |
| 72 | { |
| 73 | 63, 55, 47, 39, 31, 23, 15, |
| 74 | 7, 62, 54, 46, 38, 30, 22, |
| 75 | 14, 6, 61, 53, 45, 37, 29, |
| 76 | 21, 13, 5, 28, 20, 12, 4, |
| 77 | }; |
| 78 | |
| 79 | /* Sequence of shifts used for the key schedule. */ |
| 80 | static const char shifts[] = |
| 81 | {1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1}; |
| 82 | |
| 83 | /************************************************************************** |
| 84 | * Permuted-choice 2, to pick out the bits from the CD array that generate |
| 85 | * the key schedule. |
| 86 | **************************************************************************/ |
| 87 | static const char PC2_C[] = |
| 88 | { |
| 89 | 14, 17, 11, 24, 1, 5, |
| 90 | 3, 28, 15, 6, 21, 10, |
| 91 | 23, 19, 12, 4, 26, 8, |
| 92 | 16, 7, 27, 20, 13, 2, |
| 93 | }; |
| 94 | |
| 95 | static const char PC2_D[] = |
| 96 | { |
| 97 | 41, 52, 31, 37, 47, 55, |
| 98 | 30, 40, 51, 45, 33, 48, |
| 99 | 44, 49, 39, 56, 34, 53, |
| 100 | 46, 42, 50, 36, 29, 32, |
| 101 | }; |
| 102 | |
| 103 | /* The C and D arrays used to calculate the key schedule. */ |
| 104 | static char C[28]; |
| 105 | static char D[28]; |
| 106 | |
| 107 | /* The key schedule. Generated from the key. */ |
| 108 | static char KS[16][48]; |
| 109 | |
| 110 | /* The E bit-selection table. */ |
| 111 | static char E[48]; |
| 112 | static const char e2[] = |
| 113 | { |
| 114 | 32, 1, 2, 3, 4, 5, |
| 115 | 4, 5, 6, 7, 8, 9, |
| 116 | 8, 9, 10, 11, 12, 13, |
| 117 | 12, 13, 14, 15, 16, 17, |
| 118 | 16, 17, 18, 19, 20, 21, |
| 119 | 20, 21, 22, 23, 24, 25, |
| 120 | 24, 25, 26, 27, 28, 29, |
| 121 | 28, 29, 30, 31, 32, 1, |
| 122 | }; |
| 123 | |
| 124 | /************************************************************************** |
| 125 | * Function: setkey |
| 126 | * |
| 127 | * Description: Set up the key schedule from the encryption key. |
| 128 | * |
| 129 | * Inputs: char *key |
| 130 | * pointer to 64 character array. Each character represents a |
| 131 | * bit in the key. |
| 132 | * |
| 133 | * Returns: none |
| 134 | **************************************************************************/ |
| 135 | void setkey(char *key) |
| 136 | { |
| 137 | int i, j, k, temp; |
| 138 | |
| 139 | /********************************************************************** |
| 140 | * First, generate C and D by permuting the key. The low order bit of |
| 141 | * each 8-bit char is not used, so C and D are only 28 bits apiece. |
| 142 | **********************************************************************/ |
| 143 | for(i = 0; i < 28; i++) |
| 144 | { |
| 145 | C[i] = key[PC1_C[i] - 1]; |
| 146 | D[i] = key[PC1_D[i] - 1]; |
| 147 | } |
| 148 | |
| 149 | /********************************************************************** |
| 150 | * To generate Ki, rotate C and D according to schedule and pick up a |
| 151 | * permutation using PC2. |
| 152 | **********************************************************************/ |
| 153 | for(i = 0; i < 16; i++) |
| 154 | { |
| 155 | /* rotate */ |
| 156 | for(k = 0; k < shifts[i]; k++) |
| 157 | { |
| 158 | temp = C[0]; |
| 159 | |
| 160 | for(j = 0; j < 28 - 1; j++) |
| 161 | C[j] = C[j+1]; |
| 162 | |
| 163 | C[27] = temp; |
| 164 | temp = D[0]; |
| 165 | for(j = 0; j < 28 - 1; j++) |
| 166 | D[j] = D[j+1]; |
| 167 | |
| 168 | D[27] = temp; |
| 169 | } |
| 170 | |
| 171 | /* get Ki. Note C and D are concatenated */ |
| 172 | for(j = 0; j < 24; j++) |
| 173 | { |
| 174 | KS[i][j] = C[PC2_C[j] - 1]; |
| 175 | KS[i][j + 24] = D[PC2_D[j] - 28 -1]; |
| 176 | } |
| 177 | } |
| 178 | |
| 179 | /* load E with the initial E bit selections */ |
| 180 | for(i=0; i < 48; i++) |
| 181 | E[i] = e2[i]; |
| 182 | } |
| 183 | |
| 184 | /************************************************************************** |
| 185 | * The 8 selection functions. For some reason, they give a 0-origin |
| 186 | * index, unlike everything else. |
| 187 | **************************************************************************/ |
| 188 | |
| 189 | static const char S[8][64] = |
| 190 | { |
| 191 | { |
| 192 | 14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7, |
| 193 | 0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8, |
| 194 | 4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0, |
| 195 | 15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13 |
| 196 | }, |
| 197 | |
| 198 | { |
| 199 | 15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10, |
| 200 | 3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5, |
| 201 | 0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15, |
| 202 | 13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5, 14, 9 |
| 203 | }, |
| 204 | |
| 205 | { |
| 206 | 10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8, |
| 207 | 13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1, |
| 208 | 13, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5, 10, 14, 7, |
| 209 | 1, 10, 13, 0, 6, 9, 8, 7, 4, 15, 14, 3, 11, 5, 2, 12 |
| 210 | }, |
| 211 | |
| 212 | { |
| 213 | 7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15, |
| 214 | 13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14, 9, |
| 215 | 10, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4, |
| 216 | 3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14 |
| 217 | }, |
| 218 | |
| 219 | { |
| 220 | 2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9, |
| 221 | 14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6, |
| 222 | 4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14, |
| 223 | 11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10, 4, 5, 3 |
| 224 | }, |
| 225 | |
| 226 | { |
| 227 | 12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11, |
| 228 | 10, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 11, 3, 8, |
| 229 | 9, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6, |
| 230 | 4, 3, 2, 12, 9, 5, 15, 10, 11, 14, 1, 7, 6, 0, 8, 13 |
| 231 | }, |
| 232 | |
| 233 | { |
| 234 | 4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 10, 6, 1, |
| 235 | 13, 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6, |
| 236 | 1, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2, |
| 237 | 6, 11, 13, 8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2, 3, 12 |
| 238 | }, |
| 239 | |
| 240 | { |
| 241 | 13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7, |
| 242 | 1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 14, 9, 2, |
| 243 | 7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8, |
| 244 | 2, 1, 14, 7, 4, 10, 8, 13, 15, 12, 9, 0, 3, 5, 6, 11 |
| 245 | } |
| 246 | }; |
| 247 | |
| 248 | /************************************************************************** |
| 249 | * P is a permutation on the selected combination of the current L and key. |
| 250 | **************************************************************************/ |
| 251 | static const char P[] = |
| 252 | { |
| 253 | 16, 7, 20, 21, |
| 254 | 29, 12, 28, 17, |
| 255 | 1, 15, 23, 26, |
| 256 | 5, 18, 31, 10, |
| 257 | 2, 8, 24, 14, |
| 258 | 32, 27, 3, 9, |
| 259 | 19, 13, 30, 6, |
| 260 | 22, 11, 4, 25, |
| 261 | }; |
| 262 | |
| 263 | /* The combination of the key and the input, before selection. */ |
| 264 | static char preS[48]; |
| 265 | |
| 266 | /************************************************************************** |
| 267 | * Function: encrypt |
| 268 | * |
| 269 | * Description: Uses DES to encrypt a 64 bit block of data. Requires |
| 270 | * setkey to be invoked with the encryption key before it may |
| 271 | * be used. The results of the encryption are stored in block. |
| 272 | * |
| 273 | * Inputs: char *block |
| 274 | * pointer to 64 character array. Each character represents a |
| 275 | * bit in the data block. |
| 276 | * |
| 277 | * Returns: none |
| 278 | **************************************************************************/ |
| 279 | void encrypt(char *block) |
| 280 | { |
| 281 | int i, ii, temp, j, k; |
| 282 | |
| 283 | char left[32], right[32]; /* block in two halves */ |
| 284 | char old[32]; |
| 285 | char f[32]; |
| 286 | |
| 287 | /* First, permute the bits in the input */ |
| 288 | for(j = 0; j < 32; j++) |
| 289 | left[j] = block[IP[j] - 1]; |
| 290 | |
| 291 | for(;j < 64; j++) |
| 292 | right[j - 32] = block[IP[j] - 1]; |
| 293 | |
| 294 | /* Perform an encryption operation 16 times. */ |
| 295 | for(ii= 0; ii < 16; ii++) |
| 296 | { |
| 297 | i = ii; |
| 298 | /* Save the right array, which will be the new left. */ |
| 299 | for(j = 0; j < 32; j++) |
| 300 | old[j] = right[j]; |
| 301 | |
| 302 | /****************************************************************** |
| 303 | * Expand right to 48 bits using the E selector and |
| 304 | * exclusive-or with the current key bits. |
| 305 | ******************************************************************/ |
| 306 | for(j =0 ; j < 48; j++) |
| 307 | preS[j] = right[E[j] - 1] ^ KS[i][j]; |
| 308 | |
| 309 | /****************************************************************** |
| 310 | * The pre-select bits are now considered in 8 groups of 6 bits ea. |
| 311 | * The 8 selection functions map these 6-bit quantities into 4-bit |
| 312 | * quantities and the results are permuted to make an f(R, K). |
| 313 | * The indexing into the selection functions is peculiar; |
| 314 | * it could be simplified by rewriting the tables. |
| 315 | ******************************************************************/ |
| 316 | for(j = 0; j < 8; j++) |
| 317 | { |
| 318 | temp = 6 * j; |
| 319 | k = S[j][(preS[temp + 0] << 5) + |
| 320 | (preS[temp + 1] << 3) + |
| 321 | (preS[temp + 2] << 2) + |
| 322 | (preS[temp + 3] << 1) + |
| 323 | (preS[temp + 4] << 0) + |
| 324 | (preS[temp + 5] << 4)]; |
| 325 | |
| 326 | temp = 4 * j; |
| 327 | |
| 328 | f[temp + 0] = (k >> 3) & 01; |
| 329 | f[temp + 1] = (k >> 2) & 01; |
| 330 | f[temp + 2] = (k >> 1) & 01; |
| 331 | f[temp + 3] = (k >> 0) & 01; |
| 332 | } |
| 333 | |
| 334 | /****************************************************************** |
| 335 | * The new right is left ^ f(R, K). |
| 336 | * The f here has to be permuted first, though. |
| 337 | ******************************************************************/ |
| 338 | for(j = 0; j < 32; j++) |
| 339 | right[j] = left[j] ^ f[P[j] - 1]; |
| 340 | |
| 341 | /* Finally, the new left (the original right) is copied back. */ |
| 342 | for(j = 0; j < 32; j++) |
| 343 | left[j] = old[j]; |
| 344 | } |
| 345 | |
| 346 | /* The output left and right are reversed. */ |
| 347 | for(j = 0; j < 32; j++) |
| 348 | { |
| 349 | temp = left[j]; |
| 350 | left[j] = right[j]; |
| 351 | right[j] = temp; |
| 352 | } |
| 353 | |
| 354 | /* The final output gets the inverse permutation of the very original. */ |
| 355 | for(j = 0; j < 64; j++) |
| 356 | { |
| 357 | i = FP[j]; |
| 358 | if (i < 33) |
| 359 | block[j] = left[FP[j] - 1]; |
| 360 | else |
| 361 | block[j] = right[FP[j] - 33]; |
| 362 | } |
| 363 | } |
| 364 | |
| 365 | /************************************************************************** |
| 366 | * Function: crypt |
| 367 | * |
| 368 | * Description: Clone of Unix crypt(3) function. |
| 369 | * |
| 370 | * Inputs: char *pw |
| 371 | * pointer to 8 character encryption key (user password) |
| 372 | * char *salt |
| 373 | * pointer to 2 character salt used to modify the DES results. |
| 374 | * |
| 375 | * Returns: Pointer to static array containing the salt concatenated |
| 376 | * on to the encrypted results. Same as stored in passwd file. |
| 377 | **************************************************************************/ |
| 378 | char *crypt(char *pw, char *salt) |
| 379 | { |
| 380 | int i, j, temp; |
| 381 | char c, |
| 382 | block[66]; /* 1st store key, then results */ |
| 383 | static char iobuf[16]; /* encrypted results */ |
| 384 | |
| 385 | for(i = 0; i < 66; i++) |
| 386 | block[i] = 0; |
| 387 | |
| 388 | /* break pw into 64 bits */ |
| 389 | for(i = 0, c = *pw; c && (i < 64); i++) |
| 390 | { |
| 391 | for(j = 0; j < 7; j++, i++) |
| 392 | block[i] = (c >> (6 - j)) & 01; |
| 393 | pw++; |
| 394 | c = *pw; |
| 395 | } |
| 396 | |
| 397 | /* set key based on pw */ |
| 398 | setkey(block); |
| 399 | |
| 400 | for(i = 0; i < 66; i++) |
| 401 | block[i] = 0; |
| 402 | |
| 403 | for(i = 0; i < 2; i++) |
| 404 | { |
| 405 | /* store salt at beginning of results */ |
| 406 | c = *salt++; |
| 407 | iobuf[i] = c; |
| 408 | |
| 409 | if(c > 'Z') |
| 410 | c -= 6; |
| 411 | |
| 412 | if(c > '9') |
| 413 | c -= 7; |
| 414 | |
| 415 | c -= '.'; |
| 416 | |
| 417 | /* use salt to effect the E-bit selection */ |
| 418 | for(j = 0; j < 6; j++) |
| 419 | { |
| 420 | if((c >> j) & 01) |
| 421 | { |
| 422 | temp = E[6 * i + j]; |
| 423 | E[6 * i +j] = E[6 * i + j + 24]; |
| 424 | E[6 * i + j + 24] = temp; |
| 425 | } |
| 426 | } |
| 427 | } |
| 428 | |
| 429 | /* call DES encryption 25 times using pw as key and initial data = 0 */ |
| 430 | for(i = 0; i < 25; i++) |
| 431 | encrypt(block); |
| 432 | |
| 433 | /* format encrypted block for standard crypt(3) output */ |
| 434 | for(i=0; i < 11; i++) |
| 435 | { |
| 436 | c = 0; |
| 437 | for(j = 0; j < 6; j++) |
| 438 | { |
| 439 | c <<= 1; |
| 440 | c |= block[6 * i + j]; |
| 441 | } |
| 442 | |
| 443 | c += '.'; |
| 444 | if(c > '9') |
| 445 | c += 7; |
| 446 | |
| 447 | if(c > 'Z') |
| 448 | c += 6; |
| 449 | |
| 450 | iobuf[i + 2] = c; |
| 451 | } |
| 452 | |
| 453 | iobuf[i + 2] = '\0'; |
| 454 | |
| 455 | /* prevent premature NULL terminator */ |
| 456 | if(iobuf[1] == '\0') |
| 457 | iobuf[1] = iobuf[0]; |
| 458 | |
| 459 | return(iobuf); |
| 460 | } |