| File: | out/../deps/openssl/openssl/crypto/bn/bn_exp.c |
| Warning: | line 378, column 5 Value stored to 'wend' is never read |
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| 1 | /* |
| 2 | * Copyright 1995-2022 The OpenSSL Project Authors. All Rights Reserved. |
| 3 | * |
| 4 | * Licensed under the Apache License 2.0 (the "License"). You may not use |
| 5 | * this file except in compliance with the License. You can obtain a copy |
| 6 | * in the file LICENSE in the source distribution or at |
| 7 | * https://www.openssl.org/source/license.html |
| 8 | */ |
| 9 | |
| 10 | #include "internal/cryptlib.h" |
| 11 | #include "internal/constant_time.h" |
| 12 | #include "bn_local.h" |
| 13 | |
| 14 | #include <stdlib.h> |
| 15 | #ifdef _WIN32 |
| 16 | # include <malloc.h> |
| 17 | # ifndef alloca |
| 18 | # define alloca _alloca |
| 19 | # endif |
| 20 | #elif defined(__GNUC__4) |
| 21 | # ifndef alloca |
| 22 | # define alloca(s)__builtin_alloca (s) __builtin_alloca((s)) |
| 23 | # endif |
| 24 | #elif defined(__sun) |
| 25 | # include <alloca.h> |
| 26 | #endif |
| 27 | |
| 28 | #include "rsaz_exp.h" |
| 29 | |
| 30 | #undef SPARC_T4_MONT |
| 31 | #if defined(OPENSSL_BN_ASM_MONT1) && (defined(__sparc__) || defined(__sparc)) |
| 32 | # include "crypto/sparc_arch.h" |
| 33 | # define SPARC_T4_MONT |
| 34 | #endif |
| 35 | |
| 36 | /* maximum precomputation table size for *variable* sliding windows */ |
| 37 | #define TABLE_SIZE32 32 |
| 38 | |
| 39 | /* this one works - simple but works */ |
| 40 | int BN_exp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, BN_CTX *ctx) |
| 41 | { |
| 42 | int i, bits, ret = 0; |
| 43 | BIGNUM *v, *rr; |
| 44 | |
| 45 | if (BN_get_flags(p, BN_FLG_CONSTTIME0x04) != 0 |
| 46 | || BN_get_flags(a, BN_FLG_CONSTTIME0x04) != 0) { |
| 47 | /* BN_FLG_CONSTTIME only supported by BN_mod_exp_mont() */ |
| 48 | ERR_raise(ERR_LIB_BN, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED)(ERR_new(), ERR_set_debug("../deps/openssl/openssl/crypto/bn/bn_exp.c" ,48,__func__), ERR_set_error)((3),((257|((0x1 << 18L)|( 0x2 << 18L)))),((void*)0)); |
| 49 | return 0; |
| 50 | } |
| 51 | |
| 52 | BN_CTX_start(ctx); |
| 53 | rr = ((r == a) || (r == p)) ? BN_CTX_get(ctx) : r; |
| 54 | v = BN_CTX_get(ctx); |
| 55 | if (rr == NULL((void*)0) || v == NULL((void*)0)) |
| 56 | goto err; |
| 57 | |
| 58 | if (BN_copy(v, a) == NULL((void*)0)) |
| 59 | goto err; |
| 60 | bits = BN_num_bits(p); |
| 61 | |
| 62 | if (BN_is_odd(p)) { |
| 63 | if (BN_copy(rr, a) == NULL((void*)0)) |
| 64 | goto err; |
| 65 | } else { |
| 66 | if (!BN_one(rr)(BN_set_word((rr),1))) |
| 67 | goto err; |
| 68 | } |
| 69 | |
| 70 | for (i = 1; i < bits; i++) { |
| 71 | if (!BN_sqr(v, v, ctx)) |
| 72 | goto err; |
| 73 | if (BN_is_bit_set(p, i)) { |
| 74 | if (!BN_mul(rr, rr, v, ctx)) |
| 75 | goto err; |
| 76 | } |
| 77 | } |
| 78 | if (r != rr && BN_copy(r, rr) == NULL((void*)0)) |
| 79 | goto err; |
| 80 | |
| 81 | ret = 1; |
| 82 | err: |
| 83 | BN_CTX_end(ctx); |
| 84 | bn_check_top(r); |
| 85 | return ret; |
| 86 | } |
| 87 | |
| 88 | int BN_mod_exp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, const BIGNUM *m, |
| 89 | BN_CTX *ctx) |
| 90 | { |
| 91 | int ret; |
| 92 | |
| 93 | bn_check_top(a); |
| 94 | bn_check_top(p); |
| 95 | bn_check_top(m); |
| 96 | |
| 97 | /*- |
| 98 | * For even modulus m = 2^k*m_odd, it might make sense to compute |
| 99 | * a^p mod m_odd and a^p mod 2^k separately (with Montgomery |
| 100 | * exponentiation for the odd part), using appropriate exponent |
| 101 | * reductions, and combine the results using the CRT. |
| 102 | * |
| 103 | * For now, we use Montgomery only if the modulus is odd; otherwise, |
| 104 | * exponentiation using the reciprocal-based quick remaindering |
| 105 | * algorithm is used. |
| 106 | * |
| 107 | * (Timing obtained with expspeed.c [computations a^p mod m |
| 108 | * where a, p, m are of the same length: 256, 512, 1024, 2048, |
| 109 | * 4096, 8192 bits], compared to the running time of the |
| 110 | * standard algorithm: |
| 111 | * |
| 112 | * BN_mod_exp_mont 33 .. 40 % [AMD K6-2, Linux, debug configuration] |
| 113 | * 55 .. 77 % [UltraSparc processor, but |
| 114 | * debug-solaris-sparcv8-gcc conf.] |
| 115 | * |
| 116 | * BN_mod_exp_recp 50 .. 70 % [AMD K6-2, Linux, debug configuration] |
| 117 | * 62 .. 118 % [UltraSparc, debug-solaris-sparcv8-gcc] |
| 118 | * |
| 119 | * On the Sparc, BN_mod_exp_recp was faster than BN_mod_exp_mont |
| 120 | * at 2048 and more bits, but at 512 and 1024 bits, it was |
| 121 | * slower even than the standard algorithm! |
| 122 | * |
| 123 | * "Real" timings [linux-elf, solaris-sparcv9-gcc configurations] |
| 124 | * should be obtained when the new Montgomery reduction code |
| 125 | * has been integrated into OpenSSL.) |
| 126 | */ |
| 127 | |
| 128 | #define MONT_MUL_MOD |
| 129 | #define MONT_EXP_WORD |
| 130 | #define RECP_MUL_MOD |
| 131 | |
| 132 | #ifdef MONT_MUL_MOD |
| 133 | if (BN_is_odd(m)) { |
| 134 | # ifdef MONT_EXP_WORD |
| 135 | if (a->top == 1 && !a->neg |
| 136 | && (BN_get_flags(p, BN_FLG_CONSTTIME0x04) == 0) |
| 137 | && (BN_get_flags(a, BN_FLG_CONSTTIME0x04) == 0) |
| 138 | && (BN_get_flags(m, BN_FLG_CONSTTIME0x04) == 0)) { |
| 139 | BN_ULONGunsigned long A = a->d[0]; |
| 140 | ret = BN_mod_exp_mont_word(r, A, p, m, ctx, NULL((void*)0)); |
| 141 | } else |
| 142 | # endif |
| 143 | ret = BN_mod_exp_mont(r, a, p, m, ctx, NULL((void*)0)); |
| 144 | } else |
| 145 | #endif |
| 146 | #ifdef RECP_MUL_MOD |
| 147 | { |
| 148 | ret = BN_mod_exp_recp(r, a, p, m, ctx); |
| 149 | } |
| 150 | #else |
| 151 | { |
| 152 | ret = BN_mod_exp_simple(r, a, p, m, ctx); |
| 153 | } |
| 154 | #endif |
| 155 | |
| 156 | bn_check_top(r); |
| 157 | return ret; |
| 158 | } |
| 159 | |
| 160 | int BN_mod_exp_recp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, |
| 161 | const BIGNUM *m, BN_CTX *ctx) |
| 162 | { |
| 163 | int i, j, bits, ret = 0, wstart, wend, window, wvalue; |
| 164 | int start = 1; |
| 165 | BIGNUM *aa; |
| 166 | /* Table of variables obtained from 'ctx' */ |
| 167 | BIGNUM *val[TABLE_SIZE32]; |
| 168 | BN_RECP_CTX recp; |
| 169 | |
| 170 | if (BN_get_flags(p, BN_FLG_CONSTTIME0x04) != 0 |
| 171 | || BN_get_flags(a, BN_FLG_CONSTTIME0x04) != 0 |
| 172 | || BN_get_flags(m, BN_FLG_CONSTTIME0x04) != 0) { |
| 173 | /* BN_FLG_CONSTTIME only supported by BN_mod_exp_mont() */ |
| 174 | ERR_raise(ERR_LIB_BN, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED)(ERR_new(), ERR_set_debug("../deps/openssl/openssl/crypto/bn/bn_exp.c" ,174,__func__), ERR_set_error)((3),((257|((0x1 << 18L)| (0x2 << 18L)))),((void*)0)); |
| 175 | return 0; |
| 176 | } |
| 177 | |
| 178 | bits = BN_num_bits(p); |
| 179 | if (bits == 0) { |
| 180 | /* x**0 mod 1, or x**0 mod -1 is still zero. */ |
| 181 | if (BN_abs_is_word(m, 1)) { |
| 182 | ret = 1; |
| 183 | BN_zero(r)BN_zero_ex(r); |
| 184 | } else { |
| 185 | ret = BN_one(r)(BN_set_word((r),1)); |
| 186 | } |
| 187 | return ret; |
| 188 | } |
| 189 | |
| 190 | BN_RECP_CTX_init(&recp); |
| 191 | |
| 192 | BN_CTX_start(ctx); |
| 193 | aa = BN_CTX_get(ctx); |
| 194 | val[0] = BN_CTX_get(ctx); |
| 195 | if (val[0] == NULL((void*)0)) |
| 196 | goto err; |
| 197 | |
| 198 | if (m->neg) { |
| 199 | /* ignore sign of 'm' */ |
| 200 | if (!BN_copy(aa, m)) |
| 201 | goto err; |
| 202 | aa->neg = 0; |
| 203 | if (BN_RECP_CTX_set(&recp, aa, ctx) <= 0) |
| 204 | goto err; |
| 205 | } else { |
| 206 | if (BN_RECP_CTX_set(&recp, m, ctx) <= 0) |
| 207 | goto err; |
| 208 | } |
| 209 | |
| 210 | if (!BN_nnmod(val[0], a, m, ctx)) |
| 211 | goto err; /* 1 */ |
| 212 | if (BN_is_zero(val[0])) { |
| 213 | BN_zero(r)BN_zero_ex(r); |
| 214 | ret = 1; |
| 215 | goto err; |
| 216 | } |
| 217 | |
| 218 | window = BN_window_bits_for_exponent_size(bits)((bits) > 671 ? 6 : (bits) > 239 ? 5 : (bits) > 79 ? 4 : (bits) > 23 ? 3 : 1); |
| 219 | if (window > 1) { |
| 220 | if (!BN_mod_mul_reciprocal(aa, val[0], val[0], &recp, ctx)) |
| 221 | goto err; /* 2 */ |
| 222 | j = 1 << (window - 1); |
| 223 | for (i = 1; i < j; i++) { |
| 224 | if (((val[i] = BN_CTX_get(ctx)) == NULL((void*)0)) || |
| 225 | !BN_mod_mul_reciprocal(val[i], val[i - 1], aa, &recp, ctx)) |
| 226 | goto err; |
| 227 | } |
| 228 | } |
| 229 | |
| 230 | start = 1; /* This is used to avoid multiplication etc |
| 231 | * when there is only the value '1' in the |
| 232 | * buffer. */ |
| 233 | wvalue = 0; /* The 'value' of the window */ |
| 234 | wstart = bits - 1; /* The top bit of the window */ |
| 235 | wend = 0; /* The bottom bit of the window */ |
| 236 | |
| 237 | if (!BN_one(r)(BN_set_word((r),1))) |
| 238 | goto err; |
| 239 | |
| 240 | for (;;) { |
| 241 | if (BN_is_bit_set(p, wstart) == 0) { |
| 242 | if (!start) |
| 243 | if (!BN_mod_mul_reciprocal(r, r, r, &recp, ctx)) |
| 244 | goto err; |
| 245 | if (wstart == 0) |
| 246 | break; |
| 247 | wstart--; |
| 248 | continue; |
| 249 | } |
| 250 | /* |
| 251 | * We now have wstart on a 'set' bit, we now need to work out how bit |
| 252 | * a window to do. To do this we need to scan forward until the last |
| 253 | * set bit before the end of the window |
| 254 | */ |
| 255 | wvalue = 1; |
| 256 | wend = 0; |
| 257 | for (i = 1; i < window; i++) { |
| 258 | if (wstart - i < 0) |
| 259 | break; |
| 260 | if (BN_is_bit_set(p, wstart - i)) { |
| 261 | wvalue <<= (i - wend); |
| 262 | wvalue |= 1; |
| 263 | wend = i; |
| 264 | } |
| 265 | } |
| 266 | |
| 267 | /* wend is the size of the current window */ |
| 268 | j = wend + 1; |
| 269 | /* add the 'bytes above' */ |
| 270 | if (!start) |
| 271 | for (i = 0; i < j; i++) { |
| 272 | if (!BN_mod_mul_reciprocal(r, r, r, &recp, ctx)) |
| 273 | goto err; |
| 274 | } |
| 275 | |
| 276 | /* wvalue will be an odd number < 2^window */ |
| 277 | if (!BN_mod_mul_reciprocal(r, r, val[wvalue >> 1], &recp, ctx)) |
| 278 | goto err; |
| 279 | |
| 280 | /* move the 'window' down further */ |
| 281 | wstart -= wend + 1; |
| 282 | wvalue = 0; |
| 283 | start = 0; |
| 284 | if (wstart < 0) |
| 285 | break; |
| 286 | } |
| 287 | ret = 1; |
| 288 | err: |
| 289 | BN_CTX_end(ctx); |
| 290 | BN_RECP_CTX_free(&recp); |
| 291 | bn_check_top(r); |
| 292 | return ret; |
| 293 | } |
| 294 | |
| 295 | int BN_mod_exp_mont(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p, |
| 296 | const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *in_mont) |
| 297 | { |
| 298 | int i, j, bits, ret = 0, wstart, wend, window, wvalue; |
| 299 | int start = 1; |
| 300 | BIGNUM *d, *r; |
| 301 | const BIGNUM *aa; |
| 302 | /* Table of variables obtained from 'ctx' */ |
| 303 | BIGNUM *val[TABLE_SIZE32]; |
| 304 | BN_MONT_CTX *mont = NULL((void*)0); |
| 305 | |
| 306 | if (BN_get_flags(p, BN_FLG_CONSTTIME0x04) != 0 |
| 307 | || BN_get_flags(a, BN_FLG_CONSTTIME0x04) != 0 |
| 308 | || BN_get_flags(m, BN_FLG_CONSTTIME0x04) != 0) { |
| 309 | return BN_mod_exp_mont_consttime(rr, a, p, m, ctx, in_mont); |
| 310 | } |
| 311 | |
| 312 | bn_check_top(a); |
| 313 | bn_check_top(p); |
| 314 | bn_check_top(m); |
| 315 | |
| 316 | if (!BN_is_odd(m)) { |
| 317 | ERR_raise(ERR_LIB_BN, BN_R_CALLED_WITH_EVEN_MODULUS)(ERR_new(), ERR_set_debug("../deps/openssl/openssl/crypto/bn/bn_exp.c" ,317,__func__), ERR_set_error)((3),(102),((void*)0)); |
| 318 | return 0; |
| 319 | } |
| 320 | bits = BN_num_bits(p); |
| 321 | if (bits == 0) { |
| 322 | /* x**0 mod 1, or x**0 mod -1 is still zero. */ |
| 323 | if (BN_abs_is_word(m, 1)) { |
| 324 | ret = 1; |
| 325 | BN_zero(rr)BN_zero_ex(rr); |
| 326 | } else { |
| 327 | ret = BN_one(rr)(BN_set_word((rr),1)); |
| 328 | } |
| 329 | return ret; |
| 330 | } |
| 331 | |
| 332 | BN_CTX_start(ctx); |
| 333 | d = BN_CTX_get(ctx); |
| 334 | r = BN_CTX_get(ctx); |
| 335 | val[0] = BN_CTX_get(ctx); |
| 336 | if (val[0] == NULL((void*)0)) |
| 337 | goto err; |
| 338 | |
| 339 | /* |
| 340 | * If this is not done, things will break in the montgomery part |
| 341 | */ |
| 342 | |
| 343 | if (in_mont != NULL((void*)0)) |
| 344 | mont = in_mont; |
| 345 | else { |
| 346 | if ((mont = BN_MONT_CTX_new()) == NULL((void*)0)) |
| 347 | goto err; |
| 348 | if (!BN_MONT_CTX_set(mont, m, ctx)) |
| 349 | goto err; |
| 350 | } |
| 351 | |
| 352 | if (a->neg || BN_ucmp(a, m) >= 0) { |
| 353 | if (!BN_nnmod(val[0], a, m, ctx)) |
| 354 | goto err; |
| 355 | aa = val[0]; |
| 356 | } else |
| 357 | aa = a; |
| 358 | if (!bn_to_mont_fixed_top(val[0], aa, mont, ctx)) |
| 359 | goto err; /* 1 */ |
| 360 | |
| 361 | window = BN_window_bits_for_exponent_size(bits)((bits) > 671 ? 6 : (bits) > 239 ? 5 : (bits) > 79 ? 4 : (bits) > 23 ? 3 : 1); |
| 362 | if (window > 1) { |
| 363 | if (!bn_mul_mont_fixed_top(d, val[0], val[0], mont, ctx)) |
| 364 | goto err; /* 2 */ |
| 365 | j = 1 << (window - 1); |
| 366 | for (i = 1; i < j; i++) { |
| 367 | if (((val[i] = BN_CTX_get(ctx)) == NULL((void*)0)) || |
| 368 | !bn_mul_mont_fixed_top(val[i], val[i - 1], d, mont, ctx)) |
| 369 | goto err; |
| 370 | } |
| 371 | } |
| 372 | |
| 373 | start = 1; /* This is used to avoid multiplication etc |
| 374 | * when there is only the value '1' in the |
| 375 | * buffer. */ |
| 376 | wvalue = 0; /* The 'value' of the window */ |
| 377 | wstart = bits - 1; /* The top bit of the window */ |
| 378 | wend = 0; /* The bottom bit of the window */ |
Value stored to 'wend' is never read | |
| 379 | |
| 380 | #if 1 /* by Shay Gueron's suggestion */ |
| 381 | j = m->top; /* borrow j */ |
| 382 | if (m->d[j - 1] & (((BN_ULONGunsigned long)1) << (BN_BITS2(8 * 8) - 1))) { |
| 383 | if (bn_wexpand(r, j) == NULL((void*)0)) |
| 384 | goto err; |
| 385 | /* 2^(top*BN_BITS2) - m */ |
| 386 | r->d[0] = (0 - m->d[0]) & BN_MASK2(0xffffffffffffffffL); |
| 387 | for (i = 1; i < j; i++) |
| 388 | r->d[i] = (~m->d[i]) & BN_MASK2(0xffffffffffffffffL); |
| 389 | r->top = j; |
| 390 | r->flags |= BN_FLG_FIXED_TOP0; |
| 391 | } else |
| 392 | #endif |
| 393 | if (!bn_to_mont_fixed_top(r, BN_value_one(), mont, ctx)) |
| 394 | goto err; |
| 395 | for (;;) { |
| 396 | if (BN_is_bit_set(p, wstart) == 0) { |
| 397 | if (!start) { |
| 398 | if (!bn_mul_mont_fixed_top(r, r, r, mont, ctx)) |
| 399 | goto err; |
| 400 | } |
| 401 | if (wstart == 0) |
| 402 | break; |
| 403 | wstart--; |
| 404 | continue; |
| 405 | } |
| 406 | /* |
| 407 | * We now have wstart on a 'set' bit, we now need to work out how bit |
| 408 | * a window to do. To do this we need to scan forward until the last |
| 409 | * set bit before the end of the window |
| 410 | */ |
| 411 | wvalue = 1; |
| 412 | wend = 0; |
| 413 | for (i = 1; i < window; i++) { |
| 414 | if (wstart - i < 0) |
| 415 | break; |
| 416 | if (BN_is_bit_set(p, wstart - i)) { |
| 417 | wvalue <<= (i - wend); |
| 418 | wvalue |= 1; |
| 419 | wend = i; |
| 420 | } |
| 421 | } |
| 422 | |
| 423 | /* wend is the size of the current window */ |
| 424 | j = wend + 1; |
| 425 | /* add the 'bytes above' */ |
| 426 | if (!start) |
| 427 | for (i = 0; i < j; i++) { |
| 428 | if (!bn_mul_mont_fixed_top(r, r, r, mont, ctx)) |
| 429 | goto err; |
| 430 | } |
| 431 | |
| 432 | /* wvalue will be an odd number < 2^window */ |
| 433 | if (!bn_mul_mont_fixed_top(r, r, val[wvalue >> 1], mont, ctx)) |
| 434 | goto err; |
| 435 | |
| 436 | /* move the 'window' down further */ |
| 437 | wstart -= wend + 1; |
| 438 | wvalue = 0; |
| 439 | start = 0; |
| 440 | if (wstart < 0) |
| 441 | break; |
| 442 | } |
| 443 | /* |
| 444 | * Done with zero-padded intermediate BIGNUMs. Final BN_from_montgomery |
| 445 | * removes padding [if any] and makes return value suitable for public |
| 446 | * API consumer. |
| 447 | */ |
| 448 | #if defined(SPARC_T4_MONT) |
| 449 | if (OPENSSL_sparcv9cap_P[0] & (SPARCV9_VIS3 | SPARCV9_PREFER_FPU)) { |
| 450 | j = mont->N.top; /* borrow j */ |
| 451 | val[0]->d[0] = 1; /* borrow val[0] */ |
| 452 | for (i = 1; i < j; i++) |
| 453 | val[0]->d[i] = 0; |
| 454 | val[0]->top = j; |
| 455 | if (!BN_mod_mul_montgomery(rr, r, val[0], mont, ctx)) |
| 456 | goto err; |
| 457 | } else |
| 458 | #endif |
| 459 | if (!BN_from_montgomery(rr, r, mont, ctx)) |
| 460 | goto err; |
| 461 | ret = 1; |
| 462 | err: |
| 463 | if (in_mont == NULL((void*)0)) |
| 464 | BN_MONT_CTX_free(mont); |
| 465 | BN_CTX_end(ctx); |
| 466 | bn_check_top(rr); |
| 467 | return ret; |
| 468 | } |
| 469 | |
| 470 | static BN_ULONGunsigned long bn_get_bits(const BIGNUM *a, int bitpos) |
| 471 | { |
| 472 | BN_ULONGunsigned long ret = 0; |
| 473 | int wordpos; |
| 474 | |
| 475 | wordpos = bitpos / BN_BITS2(8 * 8); |
| 476 | bitpos %= BN_BITS2(8 * 8); |
| 477 | if (wordpos >= 0 && wordpos < a->top) { |
| 478 | ret = a->d[wordpos] & BN_MASK2(0xffffffffffffffffL); |
| 479 | if (bitpos) { |
| 480 | ret >>= bitpos; |
| 481 | if (++wordpos < a->top) |
| 482 | ret |= a->d[wordpos] << (BN_BITS2(8 * 8) - bitpos); |
| 483 | } |
| 484 | } |
| 485 | |
| 486 | return ret & BN_MASK2(0xffffffffffffffffL); |
| 487 | } |
| 488 | |
| 489 | /* |
| 490 | * BN_mod_exp_mont_consttime() stores the precomputed powers in a specific |
| 491 | * layout so that accessing any of these table values shows the same access |
| 492 | * pattern as far as cache lines are concerned. The following functions are |
| 493 | * used to transfer a BIGNUM from/to that table. |
| 494 | */ |
| 495 | |
| 496 | static int MOD_EXP_CTIME_COPY_TO_PREBUF(const BIGNUM *b, int top, |
| 497 | unsigned char *buf, int idx, |
| 498 | int window) |
| 499 | { |
| 500 | int i, j; |
| 501 | int width = 1 << window; |
| 502 | BN_ULONGunsigned long *table = (BN_ULONGunsigned long *)buf; |
| 503 | |
| 504 | if (top > b->top) |
| 505 | top = b->top; /* this works because 'buf' is explicitly |
| 506 | * zeroed */ |
| 507 | for (i = 0, j = idx; i < top; i++, j += width) { |
| 508 | table[j] = b->d[i]; |
| 509 | } |
| 510 | |
| 511 | return 1; |
| 512 | } |
| 513 | |
| 514 | static int MOD_EXP_CTIME_COPY_FROM_PREBUF(BIGNUM *b, int top, |
| 515 | unsigned char *buf, int idx, |
| 516 | int window) |
| 517 | { |
| 518 | int i, j; |
| 519 | int width = 1 << window; |
| 520 | /* |
| 521 | * We declare table 'volatile' in order to discourage compiler |
| 522 | * from reordering loads from the table. Concern is that if |
| 523 | * reordered in specific manner loads might give away the |
| 524 | * information we are trying to conceal. Some would argue that |
| 525 | * compiler can reorder them anyway, but it can as well be |
| 526 | * argued that doing so would be violation of standard... |
| 527 | */ |
| 528 | volatile BN_ULONGunsigned long *table = (volatile BN_ULONGunsigned long *)buf; |
| 529 | |
| 530 | if (bn_wexpand(b, top) == NULL((void*)0)) |
| 531 | return 0; |
| 532 | |
| 533 | if (window <= 3) { |
| 534 | for (i = 0; i < top; i++, table += width) { |
| 535 | BN_ULONGunsigned long acc = 0; |
| 536 | |
| 537 | for (j = 0; j < width; j++) { |
| 538 | acc |= table[j] & |
| 539 | ((BN_ULONGunsigned long)0 - (constant_time_eq_int(j,idx)&1)); |
| 540 | } |
| 541 | |
| 542 | b->d[i] = acc; |
| 543 | } |
| 544 | } else { |
| 545 | int xstride = 1 << (window - 2); |
| 546 | BN_ULONGunsigned long y0, y1, y2, y3; |
| 547 | |
| 548 | i = idx >> (window - 2); /* equivalent of idx / xstride */ |
| 549 | idx &= xstride - 1; /* equivalent of idx % xstride */ |
| 550 | |
| 551 | y0 = (BN_ULONGunsigned long)0 - (constant_time_eq_int(i,0)&1); |
| 552 | y1 = (BN_ULONGunsigned long)0 - (constant_time_eq_int(i,1)&1); |
| 553 | y2 = (BN_ULONGunsigned long)0 - (constant_time_eq_int(i,2)&1); |
| 554 | y3 = (BN_ULONGunsigned long)0 - (constant_time_eq_int(i,3)&1); |
| 555 | |
| 556 | for (i = 0; i < top; i++, table += width) { |
| 557 | BN_ULONGunsigned long acc = 0; |
| 558 | |
| 559 | for (j = 0; j < xstride; j++) { |
| 560 | acc |= ( (table[j + 0 * xstride] & y0) | |
| 561 | (table[j + 1 * xstride] & y1) | |
| 562 | (table[j + 2 * xstride] & y2) | |
| 563 | (table[j + 3 * xstride] & y3) ) |
| 564 | & ((BN_ULONGunsigned long)0 - (constant_time_eq_int(j,idx)&1)); |
| 565 | } |
| 566 | |
| 567 | b->d[i] = acc; |
| 568 | } |
| 569 | } |
| 570 | |
| 571 | b->top = top; |
| 572 | b->flags |= BN_FLG_FIXED_TOP0; |
| 573 | return 1; |
| 574 | } |
| 575 | |
| 576 | /* |
| 577 | * Given a pointer value, compute the next address that is a cache line |
| 578 | * multiple. |
| 579 | */ |
| 580 | #define MOD_EXP_CTIME_ALIGN(x_)((unsigned char*)(x_) + (( 64 ) - (((size_t)(x_)) & ((( 64 ) - 1))))) \ |
| 581 | ((unsigned char*)(x_) + (MOD_EXP_CTIME_MIN_CACHE_LINE_WIDTH( 64 ) - (((size_t)(x_)) & (MOD_EXP_CTIME_MIN_CACHE_LINE_MASK(( 64 ) - 1))))) |
| 582 | |
| 583 | /* |
| 584 | * This variant of BN_mod_exp_mont() uses fixed windows and the special |
| 585 | * precomputation memory layout to limit data-dependency to a minimum to |
| 586 | * protect secret exponents (cf. the hyper-threading timing attacks pointed |
| 587 | * out by Colin Percival, |
| 588 | * http://www.daemonology.net/hyperthreading-considered-harmful/) |
| 589 | */ |
| 590 | int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p, |
| 591 | const BIGNUM *m, BN_CTX *ctx, |
| 592 | BN_MONT_CTX *in_mont) |
| 593 | { |
| 594 | int i, bits, ret = 0, window, wvalue, wmask, window0; |
| 595 | int top; |
| 596 | BN_MONT_CTX *mont = NULL((void*)0); |
| 597 | |
| 598 | int numPowers; |
| 599 | unsigned char *powerbufFree = NULL((void*)0); |
| 600 | int powerbufLen = 0; |
| 601 | unsigned char *powerbuf = NULL((void*)0); |
| 602 | BIGNUM tmp, am; |
| 603 | #if defined(SPARC_T4_MONT) |
| 604 | unsigned int t4 = 0; |
| 605 | #endif |
| 606 | |
| 607 | bn_check_top(a); |
| 608 | bn_check_top(p); |
| 609 | bn_check_top(m); |
| 610 | |
| 611 | if (!BN_is_odd(m)) { |
| 612 | ERR_raise(ERR_LIB_BN, BN_R_CALLED_WITH_EVEN_MODULUS)(ERR_new(), ERR_set_debug("../deps/openssl/openssl/crypto/bn/bn_exp.c" ,612,__func__), ERR_set_error)((3),(102),((void*)0)); |
| 613 | return 0; |
| 614 | } |
| 615 | |
| 616 | top = m->top; |
| 617 | |
| 618 | /* |
| 619 | * Use all bits stored in |p|, rather than |BN_num_bits|, so we do not leak |
| 620 | * whether the top bits are zero. |
| 621 | */ |
| 622 | bits = p->top * BN_BITS2(8 * 8); |
| 623 | if (bits == 0) { |
| 624 | /* x**0 mod 1, or x**0 mod -1 is still zero. */ |
| 625 | if (BN_abs_is_word(m, 1)) { |
| 626 | ret = 1; |
| 627 | BN_zero(rr)BN_zero_ex(rr); |
| 628 | } else { |
| 629 | ret = BN_one(rr)(BN_set_word((rr),1)); |
| 630 | } |
| 631 | return ret; |
| 632 | } |
| 633 | |
| 634 | BN_CTX_start(ctx); |
| 635 | |
| 636 | /* |
| 637 | * Allocate a montgomery context if it was not supplied by the caller. If |
| 638 | * this is not done, things will break in the montgomery part. |
| 639 | */ |
| 640 | if (in_mont != NULL((void*)0)) |
| 641 | mont = in_mont; |
| 642 | else { |
| 643 | if ((mont = BN_MONT_CTX_new()) == NULL((void*)0)) |
| 644 | goto err; |
| 645 | if (!BN_MONT_CTX_set(mont, m, ctx)) |
| 646 | goto err; |
| 647 | } |
| 648 | |
| 649 | if (a->neg || BN_ucmp(a, m) >= 0) { |
| 650 | BIGNUM *reduced = BN_CTX_get(ctx); |
| 651 | if (reduced == NULL((void*)0) |
| 652 | || !BN_nnmod(reduced, a, m, ctx)) { |
| 653 | goto err; |
| 654 | } |
| 655 | a = reduced; |
| 656 | } |
| 657 | |
| 658 | #ifdef RSAZ_ENABLED |
| 659 | /* |
| 660 | * If the size of the operands allow it, perform the optimized |
| 661 | * RSAZ exponentiation. For further information see |
| 662 | * crypto/bn/rsaz_exp.c and accompanying assembly modules. |
| 663 | */ |
| 664 | if ((16 == a->top) && (16 == p->top) && (BN_num_bits(m) == 1024) |
| 665 | && rsaz_avx2_eligible()) { |
| 666 | if (NULL((void*)0) == bn_wexpand(rr, 16)) |
| 667 | goto err; |
| 668 | RSAZ_1024_mod_exp_avx2(rr->d, a->d, p->d, m->d, mont->RR.d, |
| 669 | mont->n0[0]); |
| 670 | rr->top = 16; |
| 671 | rr->neg = 0; |
| 672 | bn_correct_top(rr); |
| 673 | ret = 1; |
| 674 | goto err; |
| 675 | } else if ((8 == a->top) && (8 == p->top) && (BN_num_bits(m) == 512)) { |
| 676 | if (NULL((void*)0) == bn_wexpand(rr, 8)) |
| 677 | goto err; |
| 678 | RSAZ_512_mod_exp(rr->d, a->d, p->d, m->d, mont->n0[0], mont->RR.d); |
| 679 | rr->top = 8; |
| 680 | rr->neg = 0; |
| 681 | bn_correct_top(rr); |
| 682 | ret = 1; |
| 683 | goto err; |
| 684 | } |
| 685 | #endif |
| 686 | |
| 687 | /* Get the window size to use with size of p. */ |
| 688 | window = BN_window_bits_for_ctime_exponent_size(bits)((bits) > 937 ? 6 : (bits) > 306 ? 5 : (bits) > 89 ? 4 : (bits) > 22 ? 3 : 1); |
| 689 | #if defined(SPARC_T4_MONT) |
| 690 | if (window >= 5 && (top & 15) == 0 && top <= 64 && |
| 691 | (OPENSSL_sparcv9cap_P[1] & (CFR_MONTMUL | CFR_MONTSQR)) == |
| 692 | (CFR_MONTMUL | CFR_MONTSQR) && (t4 = OPENSSL_sparcv9cap_P[0])) |
| 693 | window = 5; |
| 694 | else |
| 695 | #endif |
| 696 | #if defined(OPENSSL_BN_ASM_MONT51) |
| 697 | if (window >= 5) { |
| 698 | window = 5; /* ~5% improvement for RSA2048 sign, and even |
| 699 | * for RSA4096 */ |
| 700 | /* reserve space for mont->N.d[] copy */ |
| 701 | powerbufLen += top * sizeof(mont->N.d[0]); |
| 702 | } |
| 703 | #endif |
| 704 | (void)0; |
| 705 | |
| 706 | /* |
| 707 | * Allocate a buffer large enough to hold all of the pre-computed powers |
| 708 | * of am, am itself and tmp. |
| 709 | */ |
| 710 | numPowers = 1 << window; |
| 711 | powerbufLen += sizeof(m->d[0]) * (top * numPowers + |
| 712 | ((2 * top) > |
| 713 | numPowers ? (2 * top) : numPowers)); |
| 714 | #ifdef alloca |
| 715 | if (powerbufLen < 3072) |
| 716 | powerbufFree = |
| 717 | alloca(powerbufLen + MOD_EXP_CTIME_MIN_CACHE_LINE_WIDTH)__builtin_alloca (powerbufLen + ( 64 )); |
| 718 | else |
| 719 | #endif |
| 720 | if ((powerbufFree = |
| 721 | OPENSSL_malloc(powerbufLen + MOD_EXP_CTIME_MIN_CACHE_LINE_WIDTH)CRYPTO_malloc(powerbufLen + ( 64 ), "../deps/openssl/openssl/crypto/bn/bn_exp.c" , 721)) |
| 722 | == NULL((void*)0)) |
| 723 | goto err; |
| 724 | |
| 725 | powerbuf = MOD_EXP_CTIME_ALIGN(powerbufFree)((unsigned char*)(powerbufFree) + (( 64 ) - (((size_t)(powerbufFree )) & ((( 64 ) - 1))))); |
| 726 | memset(powerbuf, 0, powerbufLen); |
| 727 | |
| 728 | #ifdef alloca |
| 729 | if (powerbufLen < 3072) |
| 730 | powerbufFree = NULL((void*)0); |
| 731 | #endif |
| 732 | |
| 733 | /* lay down tmp and am right after powers table */ |
| 734 | tmp.d = (BN_ULONGunsigned long *)(powerbuf + sizeof(m->d[0]) * top * numPowers); |
| 735 | am.d = tmp.d + top; |
| 736 | tmp.top = am.top = 0; |
| 737 | tmp.dmax = am.dmax = top; |
| 738 | tmp.neg = am.neg = 0; |
| 739 | tmp.flags = am.flags = BN_FLG_STATIC_DATA0x02; |
| 740 | |
| 741 | /* prepare a^0 in Montgomery domain */ |
| 742 | #if 1 /* by Shay Gueron's suggestion */ |
| 743 | if (m->d[top - 1] & (((BN_ULONGunsigned long)1) << (BN_BITS2(8 * 8) - 1))) { |
| 744 | /* 2^(top*BN_BITS2) - m */ |
| 745 | tmp.d[0] = (0 - m->d[0]) & BN_MASK2(0xffffffffffffffffL); |
| 746 | for (i = 1; i < top; i++) |
| 747 | tmp.d[i] = (~m->d[i]) & BN_MASK2(0xffffffffffffffffL); |
| 748 | tmp.top = top; |
| 749 | } else |
| 750 | #endif |
| 751 | if (!bn_to_mont_fixed_top(&tmp, BN_value_one(), mont, ctx)) |
| 752 | goto err; |
| 753 | |
| 754 | /* prepare a^1 in Montgomery domain */ |
| 755 | if (!bn_to_mont_fixed_top(&am, a, mont, ctx)) |
| 756 | goto err; |
| 757 | |
| 758 | #if defined(SPARC_T4_MONT) |
| 759 | if (t4) { |
| 760 | typedef int (*bn_pwr5_mont_f) (BN_ULONGunsigned long *tp, const BN_ULONGunsigned long *np, |
| 761 | const BN_ULONGunsigned long *n0, const void *table, |
| 762 | int power, int bits); |
| 763 | int bn_pwr5_mont_t4_8(BN_ULONGunsigned long *tp, const BN_ULONGunsigned long *np, |
| 764 | const BN_ULONGunsigned long *n0, const void *table, |
| 765 | int power, int bits); |
| 766 | int bn_pwr5_mont_t4_16(BN_ULONGunsigned long *tp, const BN_ULONGunsigned long *np, |
| 767 | const BN_ULONGunsigned long *n0, const void *table, |
| 768 | int power, int bits); |
| 769 | int bn_pwr5_mont_t4_24(BN_ULONGunsigned long *tp, const BN_ULONGunsigned long *np, |
| 770 | const BN_ULONGunsigned long *n0, const void *table, |
| 771 | int power, int bits); |
| 772 | int bn_pwr5_mont_t4_32(BN_ULONGunsigned long *tp, const BN_ULONGunsigned long *np, |
| 773 | const BN_ULONGunsigned long *n0, const void *table, |
| 774 | int power, int bits); |
| 775 | static const bn_pwr5_mont_f pwr5_funcs[4] = { |
| 776 | bn_pwr5_mont_t4_8, bn_pwr5_mont_t4_16, |
| 777 | bn_pwr5_mont_t4_24, bn_pwr5_mont_t4_32 |
| 778 | }; |
| 779 | bn_pwr5_mont_f pwr5_worker = pwr5_funcs[top / 16 - 1]; |
| 780 | |
| 781 | typedef int (*bn_mul_mont_f) (BN_ULONGunsigned long *rp, const BN_ULONGunsigned long *ap, |
| 782 | const void *bp, const BN_ULONGunsigned long *np, |
| 783 | const BN_ULONGunsigned long *n0); |
| 784 | int bn_mul_mont_t4_8(BN_ULONGunsigned long *rp, const BN_ULONGunsigned long *ap, const void *bp, |
| 785 | const BN_ULONGunsigned long *np, const BN_ULONGunsigned long *n0); |
| 786 | int bn_mul_mont_t4_16(BN_ULONGunsigned long *rp, const BN_ULONGunsigned long *ap, |
| 787 | const void *bp, const BN_ULONGunsigned long *np, |
| 788 | const BN_ULONGunsigned long *n0); |
| 789 | int bn_mul_mont_t4_24(BN_ULONGunsigned long *rp, const BN_ULONGunsigned long *ap, |
| 790 | const void *bp, const BN_ULONGunsigned long *np, |
| 791 | const BN_ULONGunsigned long *n0); |
| 792 | int bn_mul_mont_t4_32(BN_ULONGunsigned long *rp, const BN_ULONGunsigned long *ap, |
| 793 | const void *bp, const BN_ULONGunsigned long *np, |
| 794 | const BN_ULONGunsigned long *n0); |
| 795 | static const bn_mul_mont_f mul_funcs[4] = { |
| 796 | bn_mul_mont_t4_8, bn_mul_mont_t4_16, |
| 797 | bn_mul_mont_t4_24, bn_mul_mont_t4_32 |
| 798 | }; |
| 799 | bn_mul_mont_f mul_worker = mul_funcs[top / 16 - 1]; |
| 800 | |
| 801 | void bn_mul_mont_vis3(BN_ULONGunsigned long *rp, const BN_ULONGunsigned long *ap, |
| 802 | const void *bp, const BN_ULONGunsigned long *np, |
| 803 | const BN_ULONGunsigned long *n0, int num); |
| 804 | void bn_mul_mont_t4(BN_ULONGunsigned long *rp, const BN_ULONGunsigned long *ap, |
| 805 | const void *bp, const BN_ULONGunsigned long *np, |
| 806 | const BN_ULONGunsigned long *n0, int num); |
| 807 | void bn_mul_mont_gather5_t4(BN_ULONGunsigned long *rp, const BN_ULONGunsigned long *ap, |
| 808 | const void *table, const BN_ULONGunsigned long *np, |
| 809 | const BN_ULONGunsigned long *n0, int num, int power); |
| 810 | void bn_flip_n_scatter5_t4(const BN_ULONGunsigned long *inp, size_t num, |
| 811 | void *table, size_t power); |
| 812 | void bn_gather5_t4(BN_ULONGunsigned long *out, size_t num, |
| 813 | void *table, size_t power); |
| 814 | void bn_flip_t4(BN_ULONGunsigned long *dst, BN_ULONGunsigned long *src, size_t num); |
| 815 | |
| 816 | BN_ULONGunsigned long *np = mont->N.d, *n0 = mont->n0; |
| 817 | int stride = 5 * (6 - (top / 16 - 1)); /* multiple of 5, but less |
| 818 | * than 32 */ |
| 819 | |
| 820 | /* |
| 821 | * BN_to_montgomery can contaminate words above .top [in |
| 822 | * BN_DEBUG build... |
| 823 | */ |
| 824 | for (i = am.top; i < top; i++) |
| 825 | am.d[i] = 0; |
| 826 | for (i = tmp.top; i < top; i++) |
| 827 | tmp.d[i] = 0; |
| 828 | |
| 829 | bn_flip_n_scatter5_t4(tmp.d, top, powerbuf, 0); |
| 830 | bn_flip_n_scatter5_t4(am.d, top, powerbuf, 1); |
| 831 | if (!(*mul_worker) (tmp.d, am.d, am.d, np, n0) && |
| 832 | !(*mul_worker) (tmp.d, am.d, am.d, np, n0)) |
| 833 | bn_mul_mont_vis3(tmp.d, am.d, am.d, np, n0, top); |
| 834 | bn_flip_n_scatter5_t4(tmp.d, top, powerbuf, 2); |
| 835 | |
| 836 | for (i = 3; i < 32; i++) { |
| 837 | /* Calculate a^i = a^(i-1) * a */ |
| 838 | if (!(*mul_worker) (tmp.d, tmp.d, am.d, np, n0) && |
| 839 | !(*mul_worker) (tmp.d, tmp.d, am.d, np, n0)) |
| 840 | bn_mul_mont_vis3(tmp.d, tmp.d, am.d, np, n0, top); |
| 841 | bn_flip_n_scatter5_t4(tmp.d, top, powerbuf, i); |
| 842 | } |
| 843 | |
| 844 | /* switch to 64-bit domain */ |
| 845 | np = alloca(top * sizeof(BN_ULONG))__builtin_alloca (top * sizeof(unsigned long)); |
| 846 | top /= 2; |
| 847 | bn_flip_t4(np, mont->N.d, top); |
| 848 | |
| 849 | /* |
| 850 | * The exponent may not have a whole number of fixed-size windows. |
| 851 | * To simplify the main loop, the initial window has between 1 and |
| 852 | * full-window-size bits such that what remains is always a whole |
| 853 | * number of windows |
| 854 | */ |
| 855 | window0 = (bits - 1) % 5 + 1; |
| 856 | wmask = (1 << window0) - 1; |
| 857 | bits -= window0; |
| 858 | wvalue = bn_get_bits(p, bits) & wmask; |
| 859 | bn_gather5_t4(tmp.d, top, powerbuf, wvalue); |
| 860 | |
| 861 | /* |
| 862 | * Scan the exponent one window at a time starting from the most |
| 863 | * significant bits. |
| 864 | */ |
| 865 | while (bits > 0) { |
| 866 | if (bits < stride) |
| 867 | stride = bits; |
| 868 | bits -= stride; |
| 869 | wvalue = bn_get_bits(p, bits); |
| 870 | |
| 871 | if ((*pwr5_worker) (tmp.d, np, n0, powerbuf, wvalue, stride)) |
| 872 | continue; |
| 873 | /* retry once and fall back */ |
| 874 | if ((*pwr5_worker) (tmp.d, np, n0, powerbuf, wvalue, stride)) |
| 875 | continue; |
| 876 | |
| 877 | bits += stride - 5; |
| 878 | wvalue >>= stride - 5; |
| 879 | wvalue &= 31; |
| 880 | bn_mul_mont_t4(tmp.d, tmp.d, tmp.d, np, n0, top); |
| 881 | bn_mul_mont_t4(tmp.d, tmp.d, tmp.d, np, n0, top); |
| 882 | bn_mul_mont_t4(tmp.d, tmp.d, tmp.d, np, n0, top); |
| 883 | bn_mul_mont_t4(tmp.d, tmp.d, tmp.d, np, n0, top); |
| 884 | bn_mul_mont_t4(tmp.d, tmp.d, tmp.d, np, n0, top); |
| 885 | bn_mul_mont_gather5_t4(tmp.d, tmp.d, powerbuf, np, n0, top, |
| 886 | wvalue); |
| 887 | } |
| 888 | |
| 889 | bn_flip_t4(tmp.d, tmp.d, top); |
| 890 | top *= 2; |
| 891 | /* back to 32-bit domain */ |
| 892 | tmp.top = top; |
| 893 | bn_correct_top(&tmp); |
| 894 | OPENSSL_cleanse(np, top * sizeof(BN_ULONGunsigned long)); |
| 895 | } else |
| 896 | #endif |
| 897 | #if defined(OPENSSL_BN_ASM_MONT51) |
| 898 | if (window == 5 && top > 1) { |
| 899 | /* |
| 900 | * This optimization uses ideas from https://eprint.iacr.org/2011/239, |
| 901 | * specifically optimization of cache-timing attack countermeasures, |
| 902 | * pre-computation optimization, and Almost Montgomery Multiplication. |
| 903 | * |
| 904 | * The paper discusses a 4-bit window to optimize 512-bit modular |
| 905 | * exponentiation, used in RSA-1024 with CRT, but RSA-1024 is no longer |
| 906 | * important. |
| 907 | * |
| 908 | * |bn_mul_mont_gather5| and |bn_power5| implement the "almost" |
| 909 | * reduction variant, so the values here may not be fully reduced. |
| 910 | * They are bounded by R (i.e. they fit in |top| words), not |m|. |
| 911 | * Additionally, we pass these "almost" reduced inputs into |
| 912 | * |bn_mul_mont|, which implements the normal reduction variant. |
| 913 | * Given those inputs, |bn_mul_mont| may not give reduced |
| 914 | * output, but it will still produce "almost" reduced output. |
| 915 | */ |
| 916 | void bn_mul_mont_gather5(BN_ULONGunsigned long *rp, const BN_ULONGunsigned long *ap, |
| 917 | const void *table, const BN_ULONGunsigned long *np, |
| 918 | const BN_ULONGunsigned long *n0, int num, int power); |
| 919 | void bn_scatter5(const BN_ULONGunsigned long *inp, size_t num, |
| 920 | void *table, size_t power); |
| 921 | void bn_gather5(BN_ULONGunsigned long *out, size_t num, void *table, size_t power); |
| 922 | void bn_power5(BN_ULONGunsigned long *rp, const BN_ULONGunsigned long *ap, |
| 923 | const void *table, const BN_ULONGunsigned long *np, |
| 924 | const BN_ULONGunsigned long *n0, int num, int power); |
| 925 | int bn_get_bits5(const BN_ULONGunsigned long *ap, int off); |
| 926 | |
| 927 | BN_ULONGunsigned long *n0 = mont->n0, *np; |
| 928 | |
| 929 | /* |
| 930 | * BN_to_montgomery can contaminate words above .top [in |
| 931 | * BN_DEBUG build... |
| 932 | */ |
| 933 | for (i = am.top; i < top; i++) |
| 934 | am.d[i] = 0; |
| 935 | for (i = tmp.top; i < top; i++) |
| 936 | tmp.d[i] = 0; |
| 937 | |
| 938 | /* |
| 939 | * copy mont->N.d[] to improve cache locality |
| 940 | */ |
| 941 | for (np = am.d + top, i = 0; i < top; i++) |
| 942 | np[i] = mont->N.d[i]; |
| 943 | |
| 944 | bn_scatter5(tmp.d, top, powerbuf, 0); |
| 945 | bn_scatter5(am.d, am.top, powerbuf, 1); |
| 946 | bn_mul_mont(tmp.d, am.d, am.d, np, n0, top); |
| 947 | bn_scatter5(tmp.d, top, powerbuf, 2); |
| 948 | |
| 949 | # if 0 |
| 950 | for (i = 3; i < 32; i++) { |
| 951 | /* Calculate a^i = a^(i-1) * a */ |
| 952 | bn_mul_mont_gather5(tmp.d, am.d, powerbuf, np, n0, top, i - 1); |
| 953 | bn_scatter5(tmp.d, top, powerbuf, i); |
| 954 | } |
| 955 | # else |
| 956 | /* same as above, but uses squaring for 1/2 of operations */ |
| 957 | for (i = 4; i < 32; i *= 2) { |
| 958 | bn_mul_mont(tmp.d, tmp.d, tmp.d, np, n0, top); |
| 959 | bn_scatter5(tmp.d, top, powerbuf, i); |
| 960 | } |
| 961 | for (i = 3; i < 8; i += 2) { |
| 962 | int j; |
| 963 | bn_mul_mont_gather5(tmp.d, am.d, powerbuf, np, n0, top, i - 1); |
| 964 | bn_scatter5(tmp.d, top, powerbuf, i); |
| 965 | for (j = 2 * i; j < 32; j *= 2) { |
| 966 | bn_mul_mont(tmp.d, tmp.d, tmp.d, np, n0, top); |
| 967 | bn_scatter5(tmp.d, top, powerbuf, j); |
| 968 | } |
| 969 | } |
| 970 | for (; i < 16; i += 2) { |
| 971 | bn_mul_mont_gather5(tmp.d, am.d, powerbuf, np, n0, top, i - 1); |
| 972 | bn_scatter5(tmp.d, top, powerbuf, i); |
| 973 | bn_mul_mont(tmp.d, tmp.d, tmp.d, np, n0, top); |
| 974 | bn_scatter5(tmp.d, top, powerbuf, 2 * i); |
| 975 | } |
| 976 | for (; i < 32; i += 2) { |
| 977 | bn_mul_mont_gather5(tmp.d, am.d, powerbuf, np, n0, top, i - 1); |
| 978 | bn_scatter5(tmp.d, top, powerbuf, i); |
| 979 | } |
| 980 | # endif |
| 981 | /* |
| 982 | * The exponent may not have a whole number of fixed-size windows. |
| 983 | * To simplify the main loop, the initial window has between 1 and |
| 984 | * full-window-size bits such that what remains is always a whole |
| 985 | * number of windows |
| 986 | */ |
| 987 | window0 = (bits - 1) % 5 + 1; |
| 988 | wmask = (1 << window0) - 1; |
| 989 | bits -= window0; |
| 990 | wvalue = bn_get_bits(p, bits) & wmask; |
| 991 | bn_gather5(tmp.d, top, powerbuf, wvalue); |
| 992 | |
| 993 | /* |
| 994 | * Scan the exponent one window at a time starting from the most |
| 995 | * significant bits. |
| 996 | */ |
| 997 | if (top & 7) { |
| 998 | while (bits > 0) { |
| 999 | bn_mul_mont(tmp.d, tmp.d, tmp.d, np, n0, top); |
| 1000 | bn_mul_mont(tmp.d, tmp.d, tmp.d, np, n0, top); |
| 1001 | bn_mul_mont(tmp.d, tmp.d, tmp.d, np, n0, top); |
| 1002 | bn_mul_mont(tmp.d, tmp.d, tmp.d, np, n0, top); |
| 1003 | bn_mul_mont(tmp.d, tmp.d, tmp.d, np, n0, top); |
| 1004 | bn_mul_mont_gather5(tmp.d, tmp.d, powerbuf, np, n0, top, |
| 1005 | bn_get_bits5(p->d, bits -= 5)); |
| 1006 | } |
| 1007 | } else { |
| 1008 | while (bits > 0) { |
| 1009 | bn_power5(tmp.d, tmp.d, powerbuf, np, n0, top, |
| 1010 | bn_get_bits5(p->d, bits -= 5)); |
| 1011 | } |
| 1012 | } |
| 1013 | |
| 1014 | tmp.top = top; |
| 1015 | /* |
| 1016 | * The result is now in |tmp| in Montgomery form, but it may not be |
| 1017 | * fully reduced. This is within bounds for |BN_from_montgomery| |
| 1018 | * (tmp < R <= m*R) so it will, when converting from Montgomery form, |
| 1019 | * produce a fully reduced result. |
| 1020 | * |
| 1021 | * This differs from Figure 2 of the paper, which uses AMM(h, 1) to |
| 1022 | * convert from Montgomery form with unreduced output, followed by an |
| 1023 | * extra reduction step. In the paper's terminology, we replace |
| 1024 | * steps 9 and 10 with MM(h, 1). |
| 1025 | */ |
| 1026 | } else |
| 1027 | #endif |
| 1028 | { |
| 1029 | if (!MOD_EXP_CTIME_COPY_TO_PREBUF(&tmp, top, powerbuf, 0, window)) |
| 1030 | goto err; |
| 1031 | if (!MOD_EXP_CTIME_COPY_TO_PREBUF(&am, top, powerbuf, 1, window)) |
| 1032 | goto err; |
| 1033 | |
| 1034 | /* |
| 1035 | * If the window size is greater than 1, then calculate |
| 1036 | * val[i=2..2^winsize-1]. Powers are computed as a*a^(i-1) (even |
| 1037 | * powers could instead be computed as (a^(i/2))^2 to use the slight |
| 1038 | * performance advantage of sqr over mul). |
| 1039 | */ |
| 1040 | if (window > 1) { |
| 1041 | if (!bn_mul_mont_fixed_top(&tmp, &am, &am, mont, ctx)) |
| 1042 | goto err; |
| 1043 | if (!MOD_EXP_CTIME_COPY_TO_PREBUF(&tmp, top, powerbuf, 2, |
| 1044 | window)) |
| 1045 | goto err; |
| 1046 | for (i = 3; i < numPowers; i++) { |
| 1047 | /* Calculate a^i = a^(i-1) * a */ |
| 1048 | if (!bn_mul_mont_fixed_top(&tmp, &am, &tmp, mont, ctx)) |
| 1049 | goto err; |
| 1050 | if (!MOD_EXP_CTIME_COPY_TO_PREBUF(&tmp, top, powerbuf, i, |
| 1051 | window)) |
| 1052 | goto err; |
| 1053 | } |
| 1054 | } |
| 1055 | |
| 1056 | /* |
| 1057 | * The exponent may not have a whole number of fixed-size windows. |
| 1058 | * To simplify the main loop, the initial window has between 1 and |
| 1059 | * full-window-size bits such that what remains is always a whole |
| 1060 | * number of windows |
| 1061 | */ |
| 1062 | window0 = (bits - 1) % window + 1; |
| 1063 | wmask = (1 << window0) - 1; |
| 1064 | bits -= window0; |
| 1065 | wvalue = bn_get_bits(p, bits) & wmask; |
| 1066 | if (!MOD_EXP_CTIME_COPY_FROM_PREBUF(&tmp, top, powerbuf, wvalue, |
| 1067 | window)) |
| 1068 | goto err; |
| 1069 | |
| 1070 | wmask = (1 << window) - 1; |
| 1071 | /* |
| 1072 | * Scan the exponent one window at a time starting from the most |
| 1073 | * significant bits. |
| 1074 | */ |
| 1075 | while (bits > 0) { |
| 1076 | |
| 1077 | /* Square the result window-size times */ |
| 1078 | for (i = 0; i < window; i++) |
| 1079 | if (!bn_mul_mont_fixed_top(&tmp, &tmp, &tmp, mont, ctx)) |
| 1080 | goto err; |
| 1081 | |
| 1082 | /* |
| 1083 | * Get a window's worth of bits from the exponent |
| 1084 | * This avoids calling BN_is_bit_set for each bit, which |
| 1085 | * is not only slower but also makes each bit vulnerable to |
| 1086 | * EM (and likely other) side-channel attacks like One&Done |
| 1087 | * (for details see "One&Done: A Single-Decryption EM-Based |
| 1088 | * Attack on OpenSSL's Constant-Time Blinded RSA" by M. Alam, |
| 1089 | * H. Khan, M. Dey, N. Sinha, R. Callan, A. Zajic, and |
| 1090 | * M. Prvulovic, in USENIX Security'18) |
| 1091 | */ |
| 1092 | bits -= window; |
| 1093 | wvalue = bn_get_bits(p, bits) & wmask; |
| 1094 | /* |
| 1095 | * Fetch the appropriate pre-computed value from the pre-buf |
| 1096 | */ |
| 1097 | if (!MOD_EXP_CTIME_COPY_FROM_PREBUF(&am, top, powerbuf, wvalue, |
| 1098 | window)) |
| 1099 | goto err; |
| 1100 | |
| 1101 | /* Multiply the result into the intermediate result */ |
| 1102 | if (!bn_mul_mont_fixed_top(&tmp, &tmp, &am, mont, ctx)) |
| 1103 | goto err; |
| 1104 | } |
| 1105 | } |
| 1106 | |
| 1107 | /* |
| 1108 | * Done with zero-padded intermediate BIGNUMs. Final BN_from_montgomery |
| 1109 | * removes padding [if any] and makes return value suitable for public |
| 1110 | * API consumer. |
| 1111 | */ |
| 1112 | #if defined(SPARC_T4_MONT) |
| 1113 | if (OPENSSL_sparcv9cap_P[0] & (SPARCV9_VIS3 | SPARCV9_PREFER_FPU)) { |
| 1114 | am.d[0] = 1; /* borrow am */ |
| 1115 | for (i = 1; i < top; i++) |
| 1116 | am.d[i] = 0; |
| 1117 | if (!BN_mod_mul_montgomery(rr, &tmp, &am, mont, ctx)) |
| 1118 | goto err; |
| 1119 | } else |
| 1120 | #endif |
| 1121 | if (!BN_from_montgomery(rr, &tmp, mont, ctx)) |
| 1122 | goto err; |
| 1123 | ret = 1; |
| 1124 | err: |
| 1125 | if (in_mont == NULL((void*)0)) |
| 1126 | BN_MONT_CTX_free(mont); |
| 1127 | if (powerbuf != NULL((void*)0)) { |
| 1128 | OPENSSL_cleanse(powerbuf, powerbufLen); |
| 1129 | OPENSSL_free(powerbufFree)CRYPTO_free(powerbufFree, "../deps/openssl/openssl/crypto/bn/bn_exp.c" , 1129); |
| 1130 | } |
| 1131 | BN_CTX_end(ctx); |
| 1132 | return ret; |
| 1133 | } |
| 1134 | |
| 1135 | int BN_mod_exp_mont_word(BIGNUM *rr, BN_ULONGunsigned long a, const BIGNUM *p, |
| 1136 | const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *in_mont) |
| 1137 | { |
| 1138 | BN_MONT_CTX *mont = NULL((void*)0); |
| 1139 | int b, bits, ret = 0; |
| 1140 | int r_is_one; |
| 1141 | BN_ULONGunsigned long w, next_w; |
| 1142 | BIGNUM *r, *t; |
| 1143 | BIGNUM *swap_tmp; |
| 1144 | #define BN_MOD_MUL_WORD(r, w, m)(BN_mul_word(r, (w)) && ( (BN_div(((void*)0),(t),(r), (m),(ctx)) && (swap_tmp = r, r = t, t = swap_tmp, 1)) )) \ |
| 1145 | (BN_mul_word(r, (w)) && \ |
| 1146 | (/* BN_ucmp(r, (m)) < 0 ? 1 :*/ \ |
| 1147 | (BN_mod(t, r, m, ctx)BN_div(((void*)0),(t),(r),(m),(ctx)) && (swap_tmp = r, r = t, t = swap_tmp, 1)))) |
| 1148 | /* |
| 1149 | * BN_MOD_MUL_WORD is only used with 'w' large, so the BN_ucmp test is |
| 1150 | * probably more overhead than always using BN_mod (which uses BN_copy if |
| 1151 | * a similar test returns true). |
| 1152 | */ |
| 1153 | /* |
| 1154 | * We can use BN_mod and do not need BN_nnmod because our accumulator is |
| 1155 | * never negative (the result of BN_mod does not depend on the sign of |
| 1156 | * the modulus). |
| 1157 | */ |
| 1158 | #define BN_TO_MONTGOMERY_WORD(r, w, mont)(BN_set_word(r, (w)) && BN_to_montgomery(r, r, (mont) , ctx)) \ |
| 1159 | (BN_set_word(r, (w)) && BN_to_montgomery(r, r, (mont), ctx)) |
| 1160 | |
| 1161 | if (BN_get_flags(p, BN_FLG_CONSTTIME0x04) != 0 |
| 1162 | || BN_get_flags(m, BN_FLG_CONSTTIME0x04) != 0) { |
| 1163 | /* BN_FLG_CONSTTIME only supported by BN_mod_exp_mont() */ |
| 1164 | ERR_raise(ERR_LIB_BN, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED)(ERR_new(), ERR_set_debug("../deps/openssl/openssl/crypto/bn/bn_exp.c" ,1164,__func__), ERR_set_error)((3),((257|((0x1 << 18L) |(0x2 << 18L)))),((void*)0)); |
| 1165 | return 0; |
| 1166 | } |
| 1167 | |
| 1168 | bn_check_top(p); |
| 1169 | bn_check_top(m); |
| 1170 | |
| 1171 | if (!BN_is_odd(m)) { |
| 1172 | ERR_raise(ERR_LIB_BN, BN_R_CALLED_WITH_EVEN_MODULUS)(ERR_new(), ERR_set_debug("../deps/openssl/openssl/crypto/bn/bn_exp.c" ,1172,__func__), ERR_set_error)((3),(102),((void*)0)); |
| 1173 | return 0; |
| 1174 | } |
| 1175 | if (m->top == 1) |
| 1176 | a %= m->d[0]; /* make sure that 'a' is reduced */ |
| 1177 | |
| 1178 | bits = BN_num_bits(p); |
| 1179 | if (bits == 0) { |
| 1180 | /* x**0 mod 1, or x**0 mod -1 is still zero. */ |
| 1181 | if (BN_abs_is_word(m, 1)) { |
| 1182 | ret = 1; |
| 1183 | BN_zero(rr)BN_zero_ex(rr); |
| 1184 | } else { |
| 1185 | ret = BN_one(rr)(BN_set_word((rr),1)); |
| 1186 | } |
| 1187 | return ret; |
| 1188 | } |
| 1189 | if (a == 0) { |
| 1190 | BN_zero(rr)BN_zero_ex(rr); |
| 1191 | ret = 1; |
| 1192 | return ret; |
| 1193 | } |
| 1194 | |
| 1195 | BN_CTX_start(ctx); |
| 1196 | r = BN_CTX_get(ctx); |
| 1197 | t = BN_CTX_get(ctx); |
| 1198 | if (t == NULL((void*)0)) |
| 1199 | goto err; |
| 1200 | |
| 1201 | if (in_mont != NULL((void*)0)) |
| 1202 | mont = in_mont; |
| 1203 | else { |
| 1204 | if ((mont = BN_MONT_CTX_new()) == NULL((void*)0)) |
| 1205 | goto err; |
| 1206 | if (!BN_MONT_CTX_set(mont, m, ctx)) |
| 1207 | goto err; |
| 1208 | } |
| 1209 | |
| 1210 | r_is_one = 1; /* except for Montgomery factor */ |
| 1211 | |
| 1212 | /* bits-1 >= 0 */ |
| 1213 | |
| 1214 | /* The result is accumulated in the product r*w. */ |
| 1215 | w = a; /* bit 'bits-1' of 'p' is always set */ |
| 1216 | for (b = bits - 2; b >= 0; b--) { |
| 1217 | /* First, square r*w. */ |
| 1218 | next_w = w * w; |
| 1219 | if ((next_w / w) != w) { /* overflow */ |
| 1220 | if (r_is_one) { |
| 1221 | if (!BN_TO_MONTGOMERY_WORD(r, w, mont)(BN_set_word(r, (w)) && BN_to_montgomery(r, r, (mont) , ctx))) |
| 1222 | goto err; |
| 1223 | r_is_one = 0; |
| 1224 | } else { |
| 1225 | if (!BN_MOD_MUL_WORD(r, w, m)(BN_mul_word(r, (w)) && ( (BN_div(((void*)0),(t),(r), (m),(ctx)) && (swap_tmp = r, r = t, t = swap_tmp, 1)) ))) |
| 1226 | goto err; |
| 1227 | } |
| 1228 | next_w = 1; |
| 1229 | } |
| 1230 | w = next_w; |
| 1231 | if (!r_is_one) { |
| 1232 | if (!BN_mod_mul_montgomery(r, r, r, mont, ctx)) |
| 1233 | goto err; |
| 1234 | } |
| 1235 | |
| 1236 | /* Second, multiply r*w by 'a' if exponent bit is set. */ |
| 1237 | if (BN_is_bit_set(p, b)) { |
| 1238 | next_w = w * a; |
| 1239 | if ((next_w / a) != w) { /* overflow */ |
| 1240 | if (r_is_one) { |
| 1241 | if (!BN_TO_MONTGOMERY_WORD(r, w, mont)(BN_set_word(r, (w)) && BN_to_montgomery(r, r, (mont) , ctx))) |
| 1242 | goto err; |
| 1243 | r_is_one = 0; |
| 1244 | } else { |
| 1245 | if (!BN_MOD_MUL_WORD(r, w, m)(BN_mul_word(r, (w)) && ( (BN_div(((void*)0),(t),(r), (m),(ctx)) && (swap_tmp = r, r = t, t = swap_tmp, 1)) ))) |
| 1246 | goto err; |
| 1247 | } |
| 1248 | next_w = a; |
| 1249 | } |
| 1250 | w = next_w; |
| 1251 | } |
| 1252 | } |
| 1253 | |
| 1254 | /* Finally, set r:=r*w. */ |
| 1255 | if (w != 1) { |
| 1256 | if (r_is_one) { |
| 1257 | if (!BN_TO_MONTGOMERY_WORD(r, w, mont)(BN_set_word(r, (w)) && BN_to_montgomery(r, r, (mont) , ctx))) |
| 1258 | goto err; |
| 1259 | r_is_one = 0; |
| 1260 | } else { |
| 1261 | if (!BN_MOD_MUL_WORD(r, w, m)(BN_mul_word(r, (w)) && ( (BN_div(((void*)0),(t),(r), (m),(ctx)) && (swap_tmp = r, r = t, t = swap_tmp, 1)) ))) |
| 1262 | goto err; |
| 1263 | } |
| 1264 | } |
| 1265 | |
| 1266 | if (r_is_one) { /* can happen only if a == 1 */ |
| 1267 | if (!BN_one(rr)(BN_set_word((rr),1))) |
| 1268 | goto err; |
| 1269 | } else { |
| 1270 | if (!BN_from_montgomery(rr, r, mont, ctx)) |
| 1271 | goto err; |
| 1272 | } |
| 1273 | ret = 1; |
| 1274 | err: |
| 1275 | if (in_mont == NULL((void*)0)) |
| 1276 | BN_MONT_CTX_free(mont); |
| 1277 | BN_CTX_end(ctx); |
| 1278 | bn_check_top(rr); |
| 1279 | return ret; |
| 1280 | } |
| 1281 | |
| 1282 | /* The old fallback, simple version :-) */ |
| 1283 | int BN_mod_exp_simple(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, |
| 1284 | const BIGNUM *m, BN_CTX *ctx) |
| 1285 | { |
| 1286 | int i, j, bits, ret = 0, wstart, wend, window, wvalue; |
| 1287 | int start = 1; |
| 1288 | BIGNUM *d; |
| 1289 | /* Table of variables obtained from 'ctx' */ |
| 1290 | BIGNUM *val[TABLE_SIZE32]; |
| 1291 | |
| 1292 | if (BN_get_flags(p, BN_FLG_CONSTTIME0x04) != 0 |
| 1293 | || BN_get_flags(a, BN_FLG_CONSTTIME0x04) != 0 |
| 1294 | || BN_get_flags(m, BN_FLG_CONSTTIME0x04) != 0) { |
| 1295 | /* BN_FLG_CONSTTIME only supported by BN_mod_exp_mont() */ |
| 1296 | ERR_raise(ERR_LIB_BN, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED)(ERR_new(), ERR_set_debug("../deps/openssl/openssl/crypto/bn/bn_exp.c" ,1296,__func__), ERR_set_error)((3),((257|((0x1 << 18L) |(0x2 << 18L)))),((void*)0)); |
| 1297 | return 0; |
| 1298 | } |
| 1299 | |
| 1300 | bits = BN_num_bits(p); |
| 1301 | if (bits == 0) { |
| 1302 | /* x**0 mod 1, or x**0 mod -1 is still zero. */ |
| 1303 | if (BN_abs_is_word(m, 1)) { |
| 1304 | ret = 1; |
| 1305 | BN_zero(r)BN_zero_ex(r); |
| 1306 | } else { |
| 1307 | ret = BN_one(r)(BN_set_word((r),1)); |
| 1308 | } |
| 1309 | return ret; |
| 1310 | } |
| 1311 | |
| 1312 | BN_CTX_start(ctx); |
| 1313 | d = BN_CTX_get(ctx); |
| 1314 | val[0] = BN_CTX_get(ctx); |
| 1315 | if (val[0] == NULL((void*)0)) |
| 1316 | goto err; |
| 1317 | |
| 1318 | if (!BN_nnmod(val[0], a, m, ctx)) |
| 1319 | goto err; /* 1 */ |
| 1320 | if (BN_is_zero(val[0])) { |
| 1321 | BN_zero(r)BN_zero_ex(r); |
| 1322 | ret = 1; |
| 1323 | goto err; |
| 1324 | } |
| 1325 | |
| 1326 | window = BN_window_bits_for_exponent_size(bits)((bits) > 671 ? 6 : (bits) > 239 ? 5 : (bits) > 79 ? 4 : (bits) > 23 ? 3 : 1); |
| 1327 | if (window > 1) { |
| 1328 | if (!BN_mod_mul(d, val[0], val[0], m, ctx)) |
| 1329 | goto err; /* 2 */ |
| 1330 | j = 1 << (window - 1); |
| 1331 | for (i = 1; i < j; i++) { |
| 1332 | if (((val[i] = BN_CTX_get(ctx)) == NULL((void*)0)) || |
| 1333 | !BN_mod_mul(val[i], val[i - 1], d, m, ctx)) |
| 1334 | goto err; |
| 1335 | } |
| 1336 | } |
| 1337 | |
| 1338 | start = 1; /* This is used to avoid multiplication etc |
| 1339 | * when there is only the value '1' in the |
| 1340 | * buffer. */ |
| 1341 | wvalue = 0; /* The 'value' of the window */ |
| 1342 | wstart = bits - 1; /* The top bit of the window */ |
| 1343 | wend = 0; /* The bottom bit of the window */ |
| 1344 | |
| 1345 | if (!BN_one(r)(BN_set_word((r),1))) |
| 1346 | goto err; |
| 1347 | |
| 1348 | for (;;) { |
| 1349 | if (BN_is_bit_set(p, wstart) == 0) { |
| 1350 | if (!start) |
| 1351 | if (!BN_mod_mul(r, r, r, m, ctx)) |
| 1352 | goto err; |
| 1353 | if (wstart == 0) |
| 1354 | break; |
| 1355 | wstart--; |
| 1356 | continue; |
| 1357 | } |
| 1358 | /* |
| 1359 | * We now have wstart on a 'set' bit, we now need to work out how bit |
| 1360 | * a window to do. To do this we need to scan forward until the last |
| 1361 | * set bit before the end of the window |
| 1362 | */ |
| 1363 | wvalue = 1; |
| 1364 | wend = 0; |
| 1365 | for (i = 1; i < window; i++) { |
| 1366 | if (wstart - i < 0) |
| 1367 | break; |
| 1368 | if (BN_is_bit_set(p, wstart - i)) { |
| 1369 | wvalue <<= (i - wend); |
| 1370 | wvalue |= 1; |
| 1371 | wend = i; |
| 1372 | } |
| 1373 | } |
| 1374 | |
| 1375 | /* wend is the size of the current window */ |
| 1376 | j = wend + 1; |
| 1377 | /* add the 'bytes above' */ |
| 1378 | if (!start) |
| 1379 | for (i = 0; i < j; i++) { |
| 1380 | if (!BN_mod_mul(r, r, r, m, ctx)) |
| 1381 | goto err; |
| 1382 | } |
| 1383 | |
| 1384 | /* wvalue will be an odd number < 2^window */ |
| 1385 | if (!BN_mod_mul(r, r, val[wvalue >> 1], m, ctx)) |
| 1386 | goto err; |
| 1387 | |
| 1388 | /* move the 'window' down further */ |
| 1389 | wstart -= wend + 1; |
| 1390 | wvalue = 0; |
| 1391 | start = 0; |
| 1392 | if (wstart < 0) |
| 1393 | break; |
| 1394 | } |
| 1395 | ret = 1; |
| 1396 | err: |
| 1397 | BN_CTX_end(ctx); |
| 1398 | bn_check_top(r); |
| 1399 | return ret; |
| 1400 | } |
| 1401 | |
| 1402 | /* |
| 1403 | * This is a variant of modular exponentiation optimization that does |
| 1404 | * parallel 2-primes exponentiation using 256-bit (AVX512VL) AVX512_IFMA ISA |
| 1405 | * in 52-bit binary redundant representation. |
| 1406 | * If such instructions are not available, or input data size is not supported, |
| 1407 | * it falls back to two BN_mod_exp_mont_consttime() calls. |
| 1408 | */ |
| 1409 | int BN_mod_exp_mont_consttime_x2(BIGNUM *rr1, const BIGNUM *a1, const BIGNUM *p1, |
| 1410 | const BIGNUM *m1, BN_MONT_CTX *in_mont1, |
| 1411 | BIGNUM *rr2, const BIGNUM *a2, const BIGNUM *p2, |
| 1412 | const BIGNUM *m2, BN_MONT_CTX *in_mont2, |
| 1413 | BN_CTX *ctx) |
| 1414 | { |
| 1415 | int ret = 0; |
| 1416 | |
| 1417 | #ifdef RSAZ_ENABLED |
| 1418 | BN_MONT_CTX *mont1 = NULL((void*)0); |
| 1419 | BN_MONT_CTX *mont2 = NULL((void*)0); |
| 1420 | |
| 1421 | if (ossl_rsaz_avx512ifma_eligible() && |
| 1422 | ((a1->top == 16) && (p1->top == 16) && (BN_num_bits(m1) == 1024) && |
| 1423 | (a2->top == 16) && (p2->top == 16) && (BN_num_bits(m2) == 1024))) { |
| 1424 | |
| 1425 | if (bn_wexpand(rr1, 16) == NULL((void*)0)) |
| 1426 | goto err; |
| 1427 | if (bn_wexpand(rr2, 16) == NULL((void*)0)) |
| 1428 | goto err; |
| 1429 | |
| 1430 | /* Ensure that montgomery contexts are initialized */ |
| 1431 | if (in_mont1 != NULL((void*)0)) { |
| 1432 | mont1 = in_mont1; |
| 1433 | } else { |
| 1434 | if ((mont1 = BN_MONT_CTX_new()) == NULL((void*)0)) |
| 1435 | goto err; |
| 1436 | if (!BN_MONT_CTX_set(mont1, m1, ctx)) |
| 1437 | goto err; |
| 1438 | } |
| 1439 | if (in_mont2 != NULL((void*)0)) { |
| 1440 | mont2 = in_mont2; |
| 1441 | } else { |
| 1442 | if ((mont2 = BN_MONT_CTX_new()) == NULL((void*)0)) |
| 1443 | goto err; |
| 1444 | if (!BN_MONT_CTX_set(mont2, m2, ctx)) |
| 1445 | goto err; |
| 1446 | } |
| 1447 | |
| 1448 | ret = ossl_rsaz_mod_exp_avx512_x2(rr1->d, a1->d, p1->d, m1->d, |
| 1449 | mont1->RR.d, mont1->n0[0], |
| 1450 | rr2->d, a2->d, p2->d, m2->d, |
| 1451 | mont2->RR.d, mont2->n0[0], |
| 1452 | 1024 /* factor bit size */); |
| 1453 | |
| 1454 | rr1->top = 16; |
| 1455 | rr1->neg = 0; |
| 1456 | bn_correct_top(rr1); |
| 1457 | bn_check_top(rr1); |
| 1458 | |
| 1459 | rr2->top = 16; |
| 1460 | rr2->neg = 0; |
| 1461 | bn_correct_top(rr2); |
| 1462 | bn_check_top(rr2); |
| 1463 | |
| 1464 | goto err; |
| 1465 | } |
| 1466 | #endif |
| 1467 | |
| 1468 | /* rr1 = a1^p1 mod m1 */ |
| 1469 | ret = BN_mod_exp_mont_consttime(rr1, a1, p1, m1, ctx, in_mont1); |
| 1470 | /* rr2 = a2^p2 mod m2 */ |
| 1471 | ret &= BN_mod_exp_mont_consttime(rr2, a2, p2, m2, ctx, in_mont2); |
| 1472 | |
| 1473 | #ifdef RSAZ_ENABLED |
| 1474 | err: |
| 1475 | if (in_mont2 == NULL((void*)0)) |
| 1476 | BN_MONT_CTX_free(mont2); |
| 1477 | if (in_mont1 == NULL((void*)0)) |
| 1478 | BN_MONT_CTX_free(mont1); |
| 1479 | #endif |
| 1480 | |
| 1481 | return ret; |
| 1482 | } |