source: EcnlProtoTool/trunk/openssl-1.1.0e/crypto/bn/bn_mont.c@ 331

Last change on this file since 331 was 331, checked in by coas-nagasima, 6 years ago

prototoolに関連するプロジェクトをnewlibからmuslを使うよう変更・更新
ntshellをnewlibの下位の実装から、muslのsyscallの実装に変更・更新
以下のOSSをアップデート
・mruby-1.3.0
・musl-1.1.18
・onigmo-6.1.3
・tcc-0.9.27
以下のOSSを追加
・openssl-1.1.0e
・curl-7.57.0
・zlib-1.2.11
以下のmrbgemsを追加
・iij/mruby-digest
・iij/mruby-env
・iij/mruby-errno
・iij/mruby-iijson
・iij/mruby-ipaddr
・iij/mruby-mock
・iij/mruby-require
・iij/mruby-tls-openssl
  • Property svn:eol-style set to native
  • Property svn:mime-type set to text/x-csrc
File size: 11.1 KB
Line 
1/*
2 * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the OpenSSL license (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/*
11 * Details about Montgomery multiplication algorithms can be found at
12 * http://security.ece.orst.edu/publications.html, e.g.
13 * http://security.ece.orst.edu/koc/papers/j37acmon.pdf and
14 * sections 3.8 and 4.2 in http://security.ece.orst.edu/koc/papers/r01rsasw.pdf
15 */
16
17#include "internal/cryptlib.h"
18#include "bn_lcl.h"
19
20#define MONT_WORD /* use the faster word-based algorithm */
21
22#ifdef MONT_WORD
23static int BN_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont);
24#endif
25
26int BN_mod_mul_montgomery(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
27 BN_MONT_CTX *mont, BN_CTX *ctx)
28{
29 BIGNUM *tmp;
30 int ret = 0;
31#if defined(OPENSSL_BN_ASM_MONT) && defined(MONT_WORD)
32 int num = mont->N.top;
33
34 if (num > 1 && a->top == num && b->top == num) {
35 if (bn_wexpand(r, num) == NULL)
36 return (0);
37 if (bn_mul_mont(r->d, a->d, b->d, mont->N.d, mont->n0, num)) {
38 r->neg = a->neg ^ b->neg;
39 r->top = num;
40 bn_correct_top(r);
41 return (1);
42 }
43 }
44#endif
45
46 BN_CTX_start(ctx);
47 tmp = BN_CTX_get(ctx);
48 if (tmp == NULL)
49 goto err;
50
51 bn_check_top(tmp);
52 if (a == b) {
53 if (!BN_sqr(tmp, a, ctx))
54 goto err;
55 } else {
56 if (!BN_mul(tmp, a, b, ctx))
57 goto err;
58 }
59 /* reduce from aRR to aR */
60#ifdef MONT_WORD
61 if (!BN_from_montgomery_word(r, tmp, mont))
62 goto err;
63#else
64 if (!BN_from_montgomery(r, tmp, mont, ctx))
65 goto err;
66#endif
67 bn_check_top(r);
68 ret = 1;
69 err:
70 BN_CTX_end(ctx);
71 return (ret);
72}
73
74#ifdef MONT_WORD
75static int BN_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont)
76{
77 BIGNUM *n;
78 BN_ULONG *ap, *np, *rp, n0, v, carry;
79 int nl, max, i;
80
81 n = &(mont->N);
82 nl = n->top;
83 if (nl == 0) {
84 ret->top = 0;
85 return (1);
86 }
87
88 max = (2 * nl); /* carry is stored separately */
89 if (bn_wexpand(r, max) == NULL)
90 return (0);
91
92 r->neg ^= n->neg;
93 np = n->d;
94 rp = r->d;
95
96 /* clear the top words of T */
97 i = max - r->top;
98 if (i)
99 memset(&rp[r->top], 0, sizeof(*rp) * i);
100
101 r->top = max;
102 n0 = mont->n0[0];
103
104 for (carry = 0, i = 0; i < nl; i++, rp++) {
105 v = bn_mul_add_words(rp, np, nl, (rp[0] * n0) & BN_MASK2);
106 v = (v + carry + rp[nl]) & BN_MASK2;
107 carry |= (v != rp[nl]);
108 carry &= (v <= rp[nl]);
109 rp[nl] = v;
110 }
111
112 if (bn_wexpand(ret, nl) == NULL)
113 return (0);
114 ret->top = nl;
115 ret->neg = r->neg;
116
117 rp = ret->d;
118 ap = &(r->d[nl]);
119
120# define BRANCH_FREE 1
121# if BRANCH_FREE
122 {
123 BN_ULONG *nrp;
124 size_t m;
125
126 v = bn_sub_words(rp, ap, np, nl) - carry;
127 /*
128 * if subtraction result is real, then trick unconditional memcpy
129 * below to perform in-place "refresh" instead of actual copy.
130 */
131 m = (0 - (size_t)v);
132 nrp =
133 (BN_ULONG *)(((PTR_SIZE_INT) rp & ~m) | ((PTR_SIZE_INT) ap & m));
134
135 for (i = 0, nl -= 4; i < nl; i += 4) {
136 BN_ULONG t1, t2, t3, t4;
137
138 t1 = nrp[i + 0];
139 t2 = nrp[i + 1];
140 t3 = nrp[i + 2];
141 ap[i + 0] = 0;
142 t4 = nrp[i + 3];
143 ap[i + 1] = 0;
144 rp[i + 0] = t1;
145 ap[i + 2] = 0;
146 rp[i + 1] = t2;
147 ap[i + 3] = 0;
148 rp[i + 2] = t3;
149 rp[i + 3] = t4;
150 }
151 for (nl += 4; i < nl; i++)
152 rp[i] = nrp[i], ap[i] = 0;
153 }
154# else
155 if (bn_sub_words(rp, ap, np, nl) - carry)
156 memcpy(rp, ap, nl * sizeof(BN_ULONG));
157# endif
158 bn_correct_top(r);
159 bn_correct_top(ret);
160 bn_check_top(ret);
161
162 return (1);
163}
164#endif /* MONT_WORD */
165
166int BN_from_montgomery(BIGNUM *ret, const BIGNUM *a, BN_MONT_CTX *mont,
167 BN_CTX *ctx)
168{
169 int retn = 0;
170#ifdef MONT_WORD
171 BIGNUM *t;
172
173 BN_CTX_start(ctx);
174 if ((t = BN_CTX_get(ctx)) && BN_copy(t, a))
175 retn = BN_from_montgomery_word(ret, t, mont);
176 BN_CTX_end(ctx);
177#else /* !MONT_WORD */
178 BIGNUM *t1, *t2;
179
180 BN_CTX_start(ctx);
181 t1 = BN_CTX_get(ctx);
182 t2 = BN_CTX_get(ctx);
183 if (t1 == NULL || t2 == NULL)
184 goto err;
185
186 if (!BN_copy(t1, a))
187 goto err;
188 BN_mask_bits(t1, mont->ri);
189
190 if (!BN_mul(t2, t1, &mont->Ni, ctx))
191 goto err;
192 BN_mask_bits(t2, mont->ri);
193
194 if (!BN_mul(t1, t2, &mont->N, ctx))
195 goto err;
196 if (!BN_add(t2, a, t1))
197 goto err;
198 if (!BN_rshift(ret, t2, mont->ri))
199 goto err;
200
201 if (BN_ucmp(ret, &(mont->N)) >= 0) {
202 if (!BN_usub(ret, ret, &(mont->N)))
203 goto err;
204 }
205 retn = 1;
206 bn_check_top(ret);
207 err:
208 BN_CTX_end(ctx);
209#endif /* MONT_WORD */
210 return (retn);
211}
212
213BN_MONT_CTX *BN_MONT_CTX_new(void)
214{
215 BN_MONT_CTX *ret;
216
217 if ((ret = OPENSSL_malloc(sizeof(*ret))) == NULL)
218 return (NULL);
219
220 BN_MONT_CTX_init(ret);
221 ret->flags = BN_FLG_MALLOCED;
222 return (ret);
223}
224
225void BN_MONT_CTX_init(BN_MONT_CTX *ctx)
226{
227 ctx->ri = 0;
228 bn_init(&(ctx->RR));
229 bn_init(&(ctx->N));
230 bn_init(&(ctx->Ni));
231 ctx->n0[0] = ctx->n0[1] = 0;
232 ctx->flags = 0;
233}
234
235void BN_MONT_CTX_free(BN_MONT_CTX *mont)
236{
237 if (mont == NULL)
238 return;
239
240 BN_clear_free(&(mont->RR));
241 BN_clear_free(&(mont->N));
242 BN_clear_free(&(mont->Ni));
243 if (mont->flags & BN_FLG_MALLOCED)
244 OPENSSL_free(mont);
245}
246
247int BN_MONT_CTX_set(BN_MONT_CTX *mont, const BIGNUM *mod, BN_CTX *ctx)
248{
249 int ret = 0;
250 BIGNUM *Ri, *R;
251
252 if (BN_is_zero(mod))
253 return 0;
254
255 BN_CTX_start(ctx);
256 if ((Ri = BN_CTX_get(ctx)) == NULL)
257 goto err;
258 R = &(mont->RR); /* grab RR as a temp */
259 if (!BN_copy(&(mont->N), mod))
260 goto err; /* Set N */
261 mont->N.neg = 0;
262
263#ifdef MONT_WORD
264 {
265 BIGNUM tmod;
266 BN_ULONG buf[2];
267
268 bn_init(&tmod);
269 tmod.d = buf;
270 tmod.dmax = 2;
271 tmod.neg = 0;
272
273 mont->ri = (BN_num_bits(mod) + (BN_BITS2 - 1)) / BN_BITS2 * BN_BITS2;
274
275# if defined(OPENSSL_BN_ASM_MONT) && (BN_BITS2<=32)
276 /*
277 * Only certain BN_BITS2<=32 platforms actually make use of n0[1],
278 * and we could use the #else case (with a shorter R value) for the
279 * others. However, currently only the assembler files do know which
280 * is which.
281 */
282
283 BN_zero(R);
284 if (!(BN_set_bit(R, 2 * BN_BITS2)))
285 goto err;
286
287 tmod.top = 0;
288 if ((buf[0] = mod->d[0]))
289 tmod.top = 1;
290 if ((buf[1] = mod->top > 1 ? mod->d[1] : 0))
291 tmod.top = 2;
292
293 if ((BN_mod_inverse(Ri, R, &tmod, ctx)) == NULL)
294 goto err;
295 if (!BN_lshift(Ri, Ri, 2 * BN_BITS2))
296 goto err; /* R*Ri */
297 if (!BN_is_zero(Ri)) {
298 if (!BN_sub_word(Ri, 1))
299 goto err;
300 } else { /* if N mod word size == 1 */
301
302 if (bn_expand(Ri, (int)sizeof(BN_ULONG) * 2) == NULL)
303 goto err;
304 /* Ri-- (mod double word size) */
305 Ri->neg = 0;
306 Ri->d[0] = BN_MASK2;
307 Ri->d[1] = BN_MASK2;
308 Ri->top = 2;
309 }
310 if (!BN_div(Ri, NULL, Ri, &tmod, ctx))
311 goto err;
312 /*
313 * Ni = (R*Ri-1)/N, keep only couple of least significant words:
314 */
315 mont->n0[0] = (Ri->top > 0) ? Ri->d[0] : 0;
316 mont->n0[1] = (Ri->top > 1) ? Ri->d[1] : 0;
317# else
318 BN_zero(R);
319 if (!(BN_set_bit(R, BN_BITS2)))
320 goto err; /* R */
321
322 buf[0] = mod->d[0]; /* tmod = N mod word size */
323 buf[1] = 0;
324 tmod.top = buf[0] != 0 ? 1 : 0;
325 /* Ri = R^-1 mod N */
326 if ((BN_mod_inverse(Ri, R, &tmod, ctx)) == NULL)
327 goto err;
328 if (!BN_lshift(Ri, Ri, BN_BITS2))
329 goto err; /* R*Ri */
330 if (!BN_is_zero(Ri)) {
331 if (!BN_sub_word(Ri, 1))
332 goto err;
333 } else { /* if N mod word size == 1 */
334
335 if (!BN_set_word(Ri, BN_MASK2))
336 goto err; /* Ri-- (mod word size) */
337 }
338 if (!BN_div(Ri, NULL, Ri, &tmod, ctx))
339 goto err;
340 /*
341 * Ni = (R*Ri-1)/N, keep only least significant word:
342 */
343 mont->n0[0] = (Ri->top > 0) ? Ri->d[0] : 0;
344 mont->n0[1] = 0;
345# endif
346 }
347#else /* !MONT_WORD */
348 { /* bignum version */
349 mont->ri = BN_num_bits(&mont->N);
350 BN_zero(R);
351 if (!BN_set_bit(R, mont->ri))
352 goto err; /* R = 2^ri */
353 /* Ri = R^-1 mod N */
354 if ((BN_mod_inverse(Ri, R, &mont->N, ctx)) == NULL)
355 goto err;
356 if (!BN_lshift(Ri, Ri, mont->ri))
357 goto err; /* R*Ri */
358 if (!BN_sub_word(Ri, 1))
359 goto err;
360 /*
361 * Ni = (R*Ri-1) / N
362 */
363 if (!BN_div(&(mont->Ni), NULL, Ri, &mont->N, ctx))
364 goto err;
365 }
366#endif
367
368 /* setup RR for conversions */
369 BN_zero(&(mont->RR));
370 if (!BN_set_bit(&(mont->RR), mont->ri * 2))
371 goto err;
372 if (!BN_mod(&(mont->RR), &(mont->RR), &(mont->N), ctx))
373 goto err;
374
375 ret = 1;
376 err:
377 BN_CTX_end(ctx);
378 return ret;
379}
380
381BN_MONT_CTX *BN_MONT_CTX_copy(BN_MONT_CTX *to, BN_MONT_CTX *from)
382{
383 if (to == from)
384 return (to);
385
386 if (!BN_copy(&(to->RR), &(from->RR)))
387 return NULL;
388 if (!BN_copy(&(to->N), &(from->N)))
389 return NULL;
390 if (!BN_copy(&(to->Ni), &(from->Ni)))
391 return NULL;
392 to->ri = from->ri;
393 to->n0[0] = from->n0[0];
394 to->n0[1] = from->n0[1];
395 return (to);
396}
397
398BN_MONT_CTX *BN_MONT_CTX_set_locked(BN_MONT_CTX **pmont, CRYPTO_RWLOCK *lock,
399 const BIGNUM *mod, BN_CTX *ctx)
400{
401 BN_MONT_CTX *ret;
402
403 CRYPTO_THREAD_read_lock(lock);
404 ret = *pmont;
405 CRYPTO_THREAD_unlock(lock);
406 if (ret)
407 return ret;
408
409 /*
410 * We don't want to serialise globally while doing our lazy-init math in
411 * BN_MONT_CTX_set. That punishes threads that are doing independent
412 * things. Instead, punish the case where more than one thread tries to
413 * lazy-init the same 'pmont', by having each do the lazy-init math work
414 * independently and only use the one from the thread that wins the race
415 * (the losers throw away the work they've done).
416 */
417 ret = BN_MONT_CTX_new();
418 if (ret == NULL)
419 return NULL;
420 if (!BN_MONT_CTX_set(ret, mod, ctx)) {
421 BN_MONT_CTX_free(ret);
422 return NULL;
423 }
424
425 /* The locked compare-and-set, after the local work is done. */
426 CRYPTO_THREAD_write_lock(lock);
427 if (*pmont) {
428 BN_MONT_CTX_free(ret);
429 ret = *pmont;
430 } else
431 *pmont = ret;
432 CRYPTO_THREAD_unlock(lock);
433 return ret;
434}
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