1 /* 2 * Copyright 2020-2024 The OpenSSL Project Authors. All Rights Reserved. 3 * Copyright (c) 2020-2021, Intel Corporation. All Rights Reserved. 4 * 5 * Licensed under the Apache License 2.0 (the "License"). You may not use 6 * this file except in compliance with the License. You can obtain a copy 7 * in the file LICENSE in the source distribution or at 8 * https://www.openssl.org/source/license.html 9 * 10 * 11 * Originally written by Sergey Kirillov and Andrey Matyukov. 12 * Special thanks to Ilya Albrekht for his valuable hints. 13 * Intel Corporation 14 * 15 */ 16 17 #include <openssl/opensslconf.h> 18 #include <openssl/crypto.h> 19 #include "rsaz_exp.h" 20 21 #ifndef RSAZ_ENABLED 22 NON_EMPTY_TRANSLATION_UNIT 23 #else 24 # include <assert.h> 25 # include <string.h> 26 27 # define ALIGN_OF(ptr, boundary) \ 28 ((unsigned char *)(ptr) + (boundary - (((size_t)(ptr)) & (boundary - 1)))) 29 30 /* Internal radix */ 31 # define DIGIT_SIZE (52) 32 /* 52-bit mask */ 33 # define DIGIT_MASK ((uint64_t)0xFFFFFFFFFFFFF) 34 35 # define BITS2WORD8_SIZE(x) (((x) + 7) >> 3) 36 # define BITS2WORD64_SIZE(x) (((x) + 63) >> 6) 37 38 /* Number of registers required to hold |digits_num| amount of qword digits */ 39 # define NUMBER_OF_REGISTERS(digits_num, register_size) \ 40 (((digits_num) * 64 + (register_size) - 1) / (register_size)) 41 42 static ossl_inline uint64_t get_digit(const uint8_t *in, int in_len); 43 static ossl_inline void put_digit(uint8_t *out, int out_len, uint64_t digit); 44 static void to_words52(BN_ULONG *out, int out_len, const BN_ULONG *in, 45 int in_bitsize); 46 static void from_words52(BN_ULONG *bn_out, int out_bitsize, const BN_ULONG *in); 47 static ossl_inline void set_bit(BN_ULONG *a, int idx); 48 49 /* Number of |digit_size|-bit digits in |bitsize|-bit value */ 50 static ossl_inline int number_of_digits(int bitsize, int digit_size) 51 { 52 return (bitsize + digit_size - 1) / digit_size; 53 } 54 55 /* 56 * For details of the methods declared below please refer to 57 * crypto/bn/asm/rsaz-avx512.pl 58 * 59 * Naming conventions: 60 * amm = Almost Montgomery Multiplication 61 * ams = Almost Montgomery Squaring 62 * 52xZZ - data represented as array of ZZ digits in 52-bit radix 63 * _x1_/_x2_ - 1 or 2 independent inputs/outputs 64 * _ifma256 - uses 256-bit wide IFMA ISA (AVX512_IFMA256) 65 */ 66 67 void ossl_rsaz_amm52x20_x1_ifma256(BN_ULONG *res, const BN_ULONG *a, 68 const BN_ULONG *b, const BN_ULONG *m, 69 BN_ULONG k0); 70 void ossl_rsaz_amm52x20_x2_ifma256(BN_ULONG *out, const BN_ULONG *a, 71 const BN_ULONG *b, const BN_ULONG *m, 72 const BN_ULONG k0[2]); 73 void ossl_extract_multiplier_2x20_win5(BN_ULONG *red_Y, 74 const BN_ULONG *red_table, 75 int red_table_idx1, int red_table_idx2); 76 77 void ossl_rsaz_amm52x30_x1_ifma256(BN_ULONG *res, const BN_ULONG *a, 78 const BN_ULONG *b, const BN_ULONG *m, 79 BN_ULONG k0); 80 void ossl_rsaz_amm52x30_x2_ifma256(BN_ULONG *out, const BN_ULONG *a, 81 const BN_ULONG *b, const BN_ULONG *m, 82 const BN_ULONG k0[2]); 83 void ossl_extract_multiplier_2x30_win5(BN_ULONG *red_Y, 84 const BN_ULONG *red_table, 85 int red_table_idx1, int red_table_idx2); 86 87 void ossl_rsaz_amm52x40_x1_ifma256(BN_ULONG *res, const BN_ULONG *a, 88 const BN_ULONG *b, const BN_ULONG *m, 89 BN_ULONG k0); 90 void ossl_rsaz_amm52x40_x2_ifma256(BN_ULONG *out, const BN_ULONG *a, 91 const BN_ULONG *b, const BN_ULONG *m, 92 const BN_ULONG k0[2]); 93 void ossl_extract_multiplier_2x40_win5(BN_ULONG *red_Y, 94 const BN_ULONG *red_table, 95 int red_table_idx1, int red_table_idx2); 96 97 static int RSAZ_mod_exp_x2_ifma256(BN_ULONG *res, const BN_ULONG *base, 98 const BN_ULONG *exp[2], const BN_ULONG *m, 99 const BN_ULONG *rr, const BN_ULONG k0[2], 100 int modulus_bitsize); 101 102 /* 103 * Dual Montgomery modular exponentiation using prime moduli of the 104 * same bit size, optimized with AVX512 ISA. 105 * 106 * Input and output parameters for each exponentiation are independent and 107 * denoted here by index |i|, i = 1..2. 108 * 109 * Input and output are all in regular 2^64 radix. 110 * 111 * Each moduli shall be |factor_size| bit size. 112 * 113 * Supported cases: 114 * - 2x1024 115 * - 2x1536 116 * - 2x2048 117 * 118 * [out] res|i| - result of modular exponentiation: array of qword values 119 * in regular (2^64) radix. Size of array shall be enough 120 * to hold |factor_size| bits. 121 * [in] base|i| - base 122 * [in] exp|i| - exponent 123 * [in] m|i| - moduli 124 * [in] rr|i| - Montgomery parameter RR = R^2 mod m|i| 125 * [in] k0_|i| - Montgomery parameter k0 = -1/m|i| mod 2^64 126 * [in] factor_size - moduli bit size 127 * 128 * \return 0 in case of failure, 129 * 1 in case of success. 130 */ 131 int ossl_rsaz_mod_exp_avx512_x2(BN_ULONG *res1, 132 const BN_ULONG *base1, 133 const BN_ULONG *exp1, 134 const BN_ULONG *m1, 135 const BN_ULONG *rr1, 136 BN_ULONG k0_1, 137 BN_ULONG *res2, 138 const BN_ULONG *base2, 139 const BN_ULONG *exp2, 140 const BN_ULONG *m2, 141 const BN_ULONG *rr2, 142 BN_ULONG k0_2, 143 int factor_size) 144 { 145 typedef void (*AMM)(BN_ULONG *res, const BN_ULONG *a, 146 const BN_ULONG *b, const BN_ULONG *m, BN_ULONG k0); 147 int ret = 0; 148 149 /* 150 * Number of word-size (BN_ULONG) digits to store exponent in redundant 151 * representation. 152 */ 153 int exp_digits = number_of_digits(factor_size + 2, DIGIT_SIZE); 154 int coeff_pow = 4 * (DIGIT_SIZE * exp_digits - factor_size); 155 156 /* Number of YMM registers required to store exponent's digits */ 157 int ymm_regs_num = NUMBER_OF_REGISTERS(exp_digits, 256 /* ymm bit size */); 158 /* Capacity of the register set (in qwords) to store exponent */ 159 int regs_capacity = ymm_regs_num * 4; 160 161 BN_ULONG *base1_red, *m1_red, *rr1_red; 162 BN_ULONG *base2_red, *m2_red, *rr2_red; 163 BN_ULONG *coeff_red; 164 BN_ULONG *storage = NULL; 165 BN_ULONG *storage_aligned = NULL; 166 int storage_len_bytes = 7 * regs_capacity * sizeof(BN_ULONG) 167 + 64 /* alignment */; 168 169 const BN_ULONG *exp[2] = {0}; 170 BN_ULONG k0[2] = {0}; 171 /* AMM = Almost Montgomery Multiplication */ 172 AMM amm = NULL; 173 174 switch (factor_size) { 175 case 1024: 176 amm = ossl_rsaz_amm52x20_x1_ifma256; 177 break; 178 case 1536: 179 amm = ossl_rsaz_amm52x30_x1_ifma256; 180 break; 181 case 2048: 182 amm = ossl_rsaz_amm52x40_x1_ifma256; 183 break; 184 default: 185 goto err; 186 } 187 188 storage = (BN_ULONG *)OPENSSL_malloc(storage_len_bytes); 189 if (storage == NULL) 190 goto err; 191 storage_aligned = (BN_ULONG *)ALIGN_OF(storage, 64); 192 193 /* Memory layout for red(undant) representations */ 194 base1_red = storage_aligned; 195 base2_red = storage_aligned + 1 * regs_capacity; 196 m1_red = storage_aligned + 2 * regs_capacity; 197 m2_red = storage_aligned + 3 * regs_capacity; 198 rr1_red = storage_aligned + 4 * regs_capacity; 199 rr2_red = storage_aligned + 5 * regs_capacity; 200 coeff_red = storage_aligned + 6 * regs_capacity; 201 202 /* Convert base_i, m_i, rr_i, from regular to 52-bit radix */ 203 to_words52(base1_red, regs_capacity, base1, factor_size); 204 to_words52(base2_red, regs_capacity, base2, factor_size); 205 to_words52(m1_red, regs_capacity, m1, factor_size); 206 to_words52(m2_red, regs_capacity, m2, factor_size); 207 to_words52(rr1_red, regs_capacity, rr1, factor_size); 208 to_words52(rr2_red, regs_capacity, rr2, factor_size); 209 210 /* 211 * Compute target domain Montgomery converters RR' for each modulus 212 * based on precomputed original domain's RR. 213 * 214 * RR -> RR' transformation steps: 215 * (1) coeff = 2^k 216 * (2) t = AMM(RR,RR) = RR^2 / R' mod m 217 * (3) RR' = AMM(t, coeff) = RR^2 * 2^k / R'^2 mod m 218 * where 219 * k = 4 * (52 * digits52 - modlen) 220 * R = 2^(64 * ceil(modlen/64)) mod m 221 * RR = R^2 mod m 222 * R' = 2^(52 * ceil(modlen/52)) mod m 223 * 224 * EX/ modlen = 1024: k = 64, RR = 2^2048 mod m, RR' = 2^2080 mod m 225 */ 226 memset(coeff_red, 0, exp_digits * sizeof(BN_ULONG)); 227 /* (1) in reduced domain representation */ 228 set_bit(coeff_red, 64 * (int)(coeff_pow / 52) + coeff_pow % 52); 229 230 amm(rr1_red, rr1_red, rr1_red, m1_red, k0_1); /* (2) for m1 */ 231 amm(rr1_red, rr1_red, coeff_red, m1_red, k0_1); /* (3) for m1 */ 232 233 amm(rr2_red, rr2_red, rr2_red, m2_red, k0_2); /* (2) for m2 */ 234 amm(rr2_red, rr2_red, coeff_red, m2_red, k0_2); /* (3) for m2 */ 235 236 exp[0] = exp1; 237 exp[1] = exp2; 238 239 k0[0] = k0_1; 240 k0[1] = k0_2; 241 242 /* Dual (2-exps in parallel) exponentiation */ 243 ret = RSAZ_mod_exp_x2_ifma256(rr1_red, base1_red, exp, m1_red, rr1_red, 244 k0, factor_size); 245 if (!ret) 246 goto err; 247 248 /* Convert rr_i back to regular radix */ 249 from_words52(res1, factor_size, rr1_red); 250 from_words52(res2, factor_size, rr2_red); 251 252 /* bn_reduce_once_in_place expects number of BN_ULONG, not bit size */ 253 factor_size /= sizeof(BN_ULONG) * 8; 254 255 bn_reduce_once_in_place(res1, /*carry=*/0, m1, storage, factor_size); 256 bn_reduce_once_in_place(res2, /*carry=*/0, m2, storage, factor_size); 257 258 err: 259 if (storage != NULL) { 260 OPENSSL_cleanse(storage, storage_len_bytes); 261 OPENSSL_free(storage); 262 } 263 return ret; 264 } 265 266 /* 267 * Dual {1024,1536,2048}-bit w-ary modular exponentiation using prime moduli of 268 * the same bit size using Almost Montgomery Multiplication, optimized with 269 * AVX512_IFMA256 ISA. 270 * 271 * The parameter w (window size) = 5. 272 * 273 * [out] res - result of modular exponentiation: 2x{20,30,40} qword 274 * values in 2^52 radix. 275 * [in] base - base (2x{20,30,40} qword values in 2^52 radix) 276 * [in] exp - array of 2 pointers to {16,24,32} qword values in 2^64 radix. 277 * Exponent is not converted to redundant representation. 278 * [in] m - moduli (2x{20,30,40} qword values in 2^52 radix) 279 * [in] rr - Montgomery parameter for 2 moduli: 280 * RR(1024) = 2^2080 mod m. 281 * RR(1536) = 2^3120 mod m. 282 * RR(2048) = 2^4160 mod m. 283 * (2x{20,30,40} qword values in 2^52 radix) 284 * [in] k0 - Montgomery parameter for 2 moduli: k0 = -1/m mod 2^64 285 * 286 * \return (void). 287 */ 288 int RSAZ_mod_exp_x2_ifma256(BN_ULONG *out, 289 const BN_ULONG *base, 290 const BN_ULONG *exp[2], 291 const BN_ULONG *m, 292 const BN_ULONG *rr, 293 const BN_ULONG k0[2], 294 int modulus_bitsize) 295 { 296 typedef void (*DAMM)(BN_ULONG *res, const BN_ULONG *a, 297 const BN_ULONG *b, const BN_ULONG *m, 298 const BN_ULONG k0[2]); 299 typedef void (*DEXTRACT)(BN_ULONG *res, const BN_ULONG *red_table, 300 int red_table_idx, int tbl_idx); 301 302 int ret = 0; 303 int idx; 304 305 /* Exponent window size */ 306 int exp_win_size = 5; 307 int exp_win_mask = (1U << exp_win_size) - 1; 308 309 /* 310 * Number of digits (64-bit words) in redundant representation to handle 311 * modulus bits 312 */ 313 int red_digits = 0; 314 int exp_digits = 0; 315 316 BN_ULONG *storage = NULL; 317 BN_ULONG *storage_aligned = NULL; 318 int storage_len_bytes = 0; 319 320 /* Red(undant) result Y and multiplier X */ 321 BN_ULONG *red_Y = NULL; /* [2][red_digits] */ 322 BN_ULONG *red_X = NULL; /* [2][red_digits] */ 323 /* Pre-computed table of base powers */ 324 BN_ULONG *red_table = NULL; /* [1U << exp_win_size][2][red_digits] */ 325 /* Expanded exponent */ 326 BN_ULONG *expz = NULL; /* [2][exp_digits + 1] */ 327 328 /* Dual AMM */ 329 DAMM damm = NULL; 330 /* Extractor from red_table */ 331 DEXTRACT extract = NULL; 332 333 /* 334 * Squaring is done using multiplication now. That can be a subject of 335 * optimization in future. 336 */ 337 # define DAMS(r,a,m,k0) damm((r),(a),(a),(m),(k0)) 338 339 switch (modulus_bitsize) { 340 case 1024: 341 red_digits = 20; 342 exp_digits = 16; 343 damm = ossl_rsaz_amm52x20_x2_ifma256; 344 extract = ossl_extract_multiplier_2x20_win5; 345 break; 346 case 1536: 347 /* Extended with 2 digits padding to avoid mask ops in high YMM register */ 348 red_digits = 30 + 2; 349 exp_digits = 24; 350 damm = ossl_rsaz_amm52x30_x2_ifma256; 351 extract = ossl_extract_multiplier_2x30_win5; 352 break; 353 case 2048: 354 red_digits = 40; 355 exp_digits = 32; 356 damm = ossl_rsaz_amm52x40_x2_ifma256; 357 extract = ossl_extract_multiplier_2x40_win5; 358 break; 359 default: 360 goto err; 361 } 362 363 storage_len_bytes = (2 * red_digits /* red_Y */ 364 + 2 * red_digits /* red_X */ 365 + 2 * red_digits * (1U << exp_win_size) /* red_table */ 366 + 2 * (exp_digits + 1)) /* expz */ 367 * sizeof(BN_ULONG) 368 + 64; /* alignment */ 369 370 storage = (BN_ULONG *)OPENSSL_zalloc(storage_len_bytes); 371 if (storage == NULL) 372 goto err; 373 storage_aligned = (BN_ULONG *)ALIGN_OF(storage, 64); 374 375 red_Y = storage_aligned; 376 red_X = red_Y + 2 * red_digits; 377 red_table = red_X + 2 * red_digits; 378 expz = red_table + 2 * red_digits * (1U << exp_win_size); 379 380 /* 381 * Compute table of powers base^i, i = 0, ..., (2^EXP_WIN_SIZE) - 1 382 * table[0] = mont(x^0) = mont(1) 383 * table[1] = mont(x^1) = mont(x) 384 */ 385 red_X[0 * red_digits] = 1; 386 red_X[1 * red_digits] = 1; 387 damm(&red_table[0 * 2 * red_digits], (const BN_ULONG*)red_X, rr, m, k0); 388 damm(&red_table[1 * 2 * red_digits], base, rr, m, k0); 389 390 for (idx = 1; idx < (int)((1U << exp_win_size) / 2); idx++) { 391 DAMS(&red_table[(2 * idx + 0) * 2 * red_digits], 392 &red_table[(1 * idx) * 2 * red_digits], m, k0); 393 damm(&red_table[(2 * idx + 1) * 2 * red_digits], 394 &red_table[(2 * idx) * 2 * red_digits], 395 &red_table[1 * 2 * red_digits], m, k0); 396 } 397 398 /* Copy and expand exponents */ 399 memcpy(&expz[0 * (exp_digits + 1)], exp[0], exp_digits * sizeof(BN_ULONG)); 400 expz[1 * (exp_digits + 1) - 1] = 0; 401 memcpy(&expz[1 * (exp_digits + 1)], exp[1], exp_digits * sizeof(BN_ULONG)); 402 expz[2 * (exp_digits + 1) - 1] = 0; 403 404 /* Exponentiation */ 405 { 406 const int rem = modulus_bitsize % exp_win_size; 407 const BN_ULONG table_idx_mask = exp_win_mask; 408 409 int exp_bit_no = modulus_bitsize - rem; 410 int exp_chunk_no = exp_bit_no / 64; 411 int exp_chunk_shift = exp_bit_no % 64; 412 413 BN_ULONG red_table_idx_0, red_table_idx_1; 414 415 /* 416 * If rem == 0, then 417 * exp_bit_no = modulus_bitsize - exp_win_size 418 * However, this isn't possible because rem is { 1024, 1536, 2048 } % 5 419 * which is { 4, 1, 3 } respectively. 420 * 421 * If this assertion ever fails the fix above is easy. 422 */ 423 OPENSSL_assert(rem != 0); 424 425 /* Process 1-st exp window - just init result */ 426 red_table_idx_0 = expz[exp_chunk_no + 0 * (exp_digits + 1)]; 427 red_table_idx_1 = expz[exp_chunk_no + 1 * (exp_digits + 1)]; 428 429 /* 430 * The function operates with fixed moduli sizes divisible by 64, 431 * thus table index here is always in supported range [0, EXP_WIN_SIZE). 432 */ 433 red_table_idx_0 >>= exp_chunk_shift; 434 red_table_idx_1 >>= exp_chunk_shift; 435 436 extract(&red_Y[0 * red_digits], (const BN_ULONG*)red_table, (int)red_table_idx_0, (int)red_table_idx_1); 437 438 /* Process other exp windows */ 439 for (exp_bit_no -= exp_win_size; exp_bit_no >= 0; exp_bit_no -= exp_win_size) { 440 /* Extract pre-computed multiplier from the table */ 441 { 442 BN_ULONG T; 443 444 exp_chunk_no = exp_bit_no / 64; 445 exp_chunk_shift = exp_bit_no % 64; 446 { 447 red_table_idx_0 = expz[exp_chunk_no + 0 * (exp_digits + 1)]; 448 T = expz[exp_chunk_no + 1 + 0 * (exp_digits + 1)]; 449 450 red_table_idx_0 >>= exp_chunk_shift; 451 /* 452 * Get additional bits from then next quadword 453 * when 64-bit boundaries are crossed. 454 */ 455 if (exp_chunk_shift > 64 - exp_win_size) { 456 T <<= (64 - exp_chunk_shift); 457 red_table_idx_0 ^= T; 458 } 459 red_table_idx_0 &= table_idx_mask; 460 } 461 { 462 red_table_idx_1 = expz[exp_chunk_no + 1 * (exp_digits + 1)]; 463 T = expz[exp_chunk_no + 1 + 1 * (exp_digits + 1)]; 464 465 red_table_idx_1 >>= exp_chunk_shift; 466 /* 467 * Get additional bits from then next quadword 468 * when 64-bit boundaries are crossed. 469 */ 470 if (exp_chunk_shift > 64 - exp_win_size) { 471 T <<= (64 - exp_chunk_shift); 472 red_table_idx_1 ^= T; 473 } 474 red_table_idx_1 &= table_idx_mask; 475 } 476 477 extract(&red_X[0 * red_digits], (const BN_ULONG*)red_table, (int)red_table_idx_0, (int)red_table_idx_1); 478 } 479 480 /* Series of squaring */ 481 DAMS((BN_ULONG*)red_Y, (const BN_ULONG*)red_Y, m, k0); 482 DAMS((BN_ULONG*)red_Y, (const BN_ULONG*)red_Y, m, k0); 483 DAMS((BN_ULONG*)red_Y, (const BN_ULONG*)red_Y, m, k0); 484 DAMS((BN_ULONG*)red_Y, (const BN_ULONG*)red_Y, m, k0); 485 DAMS((BN_ULONG*)red_Y, (const BN_ULONG*)red_Y, m, k0); 486 487 damm((BN_ULONG*)red_Y, (const BN_ULONG*)red_Y, (const BN_ULONG*)red_X, m, k0); 488 } 489 } 490 491 /* 492 * 493 * NB: After the last AMM of exponentiation in Montgomery domain, the result 494 * may be (modulus_bitsize + 1), but the conversion out of Montgomery domain 495 * performs an AMM(x,1) which guarantees that the final result is less than 496 * |m|, so no conditional subtraction is needed here. See [1] for details. 497 * 498 * [1] Gueron, S. Efficient software implementations of modular exponentiation. 499 * DOI: 10.1007/s13389-012-0031-5 500 */ 501 502 /* Convert result back in regular 2^52 domain */ 503 memset(red_X, 0, 2 * red_digits * sizeof(BN_ULONG)); 504 red_X[0 * red_digits] = 1; 505 red_X[1 * red_digits] = 1; 506 damm(out, (const BN_ULONG*)red_Y, (const BN_ULONG*)red_X, m, k0); 507 508 ret = 1; 509 510 err: 511 if (storage != NULL) { 512 /* Clear whole storage */ 513 OPENSSL_cleanse(storage, storage_len_bytes); 514 OPENSSL_free(storage); 515 } 516 517 #undef DAMS 518 return ret; 519 } 520 521 static ossl_inline uint64_t get_digit(const uint8_t *in, int in_len) 522 { 523 uint64_t digit = 0; 524 525 assert(in != NULL); 526 assert(in_len <= 8); 527 528 for (; in_len > 0; in_len--) { 529 digit <<= 8; 530 digit += (uint64_t)(in[in_len - 1]); 531 } 532 return digit; 533 } 534 535 /* 536 * Convert array of words in regular (base=2^64) representation to array of 537 * words in redundant (base=2^52) one. 538 */ 539 static void to_words52(BN_ULONG *out, int out_len, 540 const BN_ULONG *in, int in_bitsize) 541 { 542 uint8_t *in_str = NULL; 543 544 assert(out != NULL); 545 assert(in != NULL); 546 /* Check destination buffer capacity */ 547 assert(out_len >= number_of_digits(in_bitsize, DIGIT_SIZE)); 548 549 in_str = (uint8_t *)in; 550 551 for (; in_bitsize >= (2 * DIGIT_SIZE); in_bitsize -= (2 * DIGIT_SIZE), out += 2) { 552 uint64_t digit; 553 554 memcpy(&digit, in_str, sizeof(digit)); 555 out[0] = digit & DIGIT_MASK; 556 in_str += 6; 557 memcpy(&digit, in_str, sizeof(digit)); 558 out[1] = (digit >> 4) & DIGIT_MASK; 559 in_str += 7; 560 out_len -= 2; 561 } 562 563 if (in_bitsize > DIGIT_SIZE) { 564 uint64_t digit = get_digit(in_str, 7); 565 566 out[0] = digit & DIGIT_MASK; 567 in_str += 6; 568 in_bitsize -= DIGIT_SIZE; 569 digit = get_digit(in_str, BITS2WORD8_SIZE(in_bitsize)); 570 out[1] = digit >> 4; 571 out += 2; 572 out_len -= 2; 573 } else if (in_bitsize > 0) { 574 out[0] = get_digit(in_str, BITS2WORD8_SIZE(in_bitsize)); 575 out++; 576 out_len--; 577 } 578 579 memset(out, 0, out_len * sizeof(BN_ULONG)); 580 } 581 582 static ossl_inline void put_digit(uint8_t *out, int out_len, uint64_t digit) 583 { 584 assert(out != NULL); 585 assert(out_len <= 8); 586 587 for (; out_len > 0; out_len--) { 588 *out++ = (uint8_t)(digit & 0xFF); 589 digit >>= 8; 590 } 591 } 592 593 /* 594 * Convert array of words in redundant (base=2^52) representation to array of 595 * words in regular (base=2^64) one. 596 */ 597 static void from_words52(BN_ULONG *out, int out_bitsize, const BN_ULONG *in) 598 { 599 int i; 600 int out_len = BITS2WORD64_SIZE(out_bitsize); 601 602 assert(out != NULL); 603 assert(in != NULL); 604 605 for (i = 0; i < out_len; i++) 606 out[i] = 0; 607 608 { 609 uint8_t *out_str = (uint8_t *)out; 610 611 for (; out_bitsize >= (2 * DIGIT_SIZE); 612 out_bitsize -= (2 * DIGIT_SIZE), in += 2) { 613 uint64_t digit; 614 615 digit = in[0]; 616 memcpy(out_str, &digit, sizeof(digit)); 617 out_str += 6; 618 digit = digit >> 48 | in[1] << 4; 619 memcpy(out_str, &digit, sizeof(digit)); 620 out_str += 7; 621 } 622 623 if (out_bitsize > DIGIT_SIZE) { 624 put_digit(out_str, 7, in[0]); 625 out_str += 6; 626 out_bitsize -= DIGIT_SIZE; 627 put_digit(out_str, BITS2WORD8_SIZE(out_bitsize), 628 (in[1] << 4 | in[0] >> 48)); 629 } else if (out_bitsize) { 630 put_digit(out_str, BITS2WORD8_SIZE(out_bitsize), in[0]); 631 } 632 } 633 } 634 635 /* 636 * Set bit at index |idx| in the words array |a|. 637 * It does not do any boundaries checks, make sure the index is valid before 638 * calling the function. 639 */ 640 static ossl_inline void set_bit(BN_ULONG *a, int idx) 641 { 642 assert(a != NULL); 643 644 { 645 int i, j; 646 647 i = idx / BN_BITS2; 648 j = idx % BN_BITS2; 649 a[i] |= (((BN_ULONG)1) << j); 650 } 651 } 652 653 #endif 654
