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diff --git a/src/lib/libcrypto/bn/bn_mont.c b/src/lib/libcrypto/bn/bn_mont.c
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1/* crypto/bn/bn_mont.c */
2/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
3 * All rights reserved.
4 *
5 * This package is an SSL implementation written
6 * by Eric Young (eay@cryptsoft.com).
7 * The implementation was written so as to conform with Netscapes SSL.
8 *
9 * This library is free for commercial and non-commercial use as long as
10 * the following conditions are aheared to. The following conditions
11 * apply to all code found in this distribution, be it the RC4, RSA,
12 * lhash, DES, etc., code; not just the SSL code. The SSL documentation
13 * included with this distribution is covered by the same copyright terms
14 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
15 *
16 * Copyright remains Eric Young's, and as such any Copyright notices in
17 * the code are not to be removed.
18 * If this package is used in a product, Eric Young should be given attribution
19 * as the author of the parts of the library used.
20 * This can be in the form of a textual message at program startup or
21 * in documentation (online or textual) provided with the package.
22 *
23 * Redistribution and use in source and binary forms, with or without
24 * modification, are permitted provided that the following conditions
25 * are met:
26 * 1. Redistributions of source code must retain the copyright
27 * notice, this list of conditions and the following disclaimer.
28 * 2. Redistributions in binary form must reproduce the above copyright
29 * notice, this list of conditions and the following disclaimer in the
30 * documentation and/or other materials provided with the distribution.
31 * 3. All advertising materials mentioning features or use of this software
32 * must display the following acknowledgement:
33 * "This product includes cryptographic software written by
34 * Eric Young (eay@cryptsoft.com)"
35 * The word 'cryptographic' can be left out if the rouines from the library
36 * being used are not cryptographic related :-).
37 * 4. If you include any Windows specific code (or a derivative thereof) from
38 * the apps directory (application code) you must include an acknowledgement:
39 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
40 *
41 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
42 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
43 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
44 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
45 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
46 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
47 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
49 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
50 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
51 * SUCH DAMAGE.
52 *
53 * The licence and distribution terms for any publically available version or
54 * derivative of this code cannot be changed. i.e. this code cannot simply be
55 * copied and put under another distribution licence
56 * [including the GNU Public Licence.]
57 */
58/* ====================================================================
59 * Copyright (c) 1998-2006 The OpenSSL Project. All rights reserved.
60 *
61 * Redistribution and use in source and binary forms, with or without
62 * modification, are permitted provided that the following conditions
63 * are met:
64 *
65 * 1. Redistributions of source code must retain the above copyright
66 * notice, this list of conditions and the following disclaimer.
67 *
68 * 2. Redistributions in binary form must reproduce the above copyright
69 * notice, this list of conditions and the following disclaimer in
70 * the documentation and/or other materials provided with the
71 * distribution.
72 *
73 * 3. All advertising materials mentioning features or use of this
74 * software must display the following acknowledgment:
75 * "This product includes software developed by the OpenSSL Project
76 * for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
77 *
78 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
79 * endorse or promote products derived from this software without
80 * prior written permission. For written permission, please contact
81 * openssl-core@openssl.org.
82 *
83 * 5. Products derived from this software may not be called "OpenSSL"
84 * nor may "OpenSSL" appear in their names without prior written
85 * permission of the OpenSSL Project.
86 *
87 * 6. Redistributions of any form whatsoever must retain the following
88 * acknowledgment:
89 * "This product includes software developed by the OpenSSL Project
90 * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
91 *
92 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
93 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
94 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
95 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
96 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
97 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
98 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
99 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
100 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
101 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
102 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
103 * OF THE POSSIBILITY OF SUCH DAMAGE.
104 * ====================================================================
105 *
106 * This product includes cryptographic software written by Eric Young
107 * (eay@cryptsoft.com). This product includes software written by Tim
108 * Hudson (tjh@cryptsoft.com).
109 *
110 */
111
112/*
113 * Details about Montgomery multiplication algorithms can be found at
114 * http://security.ece.orst.edu/publications.html, e.g.
115 * http://security.ece.orst.edu/koc/papers/j37acmon.pdf and
116 * sections 3.8 and 4.2 in http://security.ece.orst.edu/koc/papers/r01rsasw.pdf
117 */
118
119#include <stdio.h>
120#include "cryptlib.h"
121#include "bn_lcl.h"
122
123#define MONT_WORD /* use the faster word-based algorithm */
124
125#ifdef MONT_WORD
126static int BN_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont);
127#endif
128
129int BN_mod_mul_montgomery(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
130 BN_MONT_CTX *mont, BN_CTX *ctx)
131 {
132 BIGNUM *tmp;
133 int ret=0;
134#if defined(OPENSSL_BN_ASM_MONT) && defined(MONT_WORD)
135 int num = mont->N.top;
136
137 if (num>1 && a->top==num && b->top==num)
138 {
139 if (bn_wexpand(r,num) == NULL) return(0);
140 if (bn_mul_mont(r->d,a->d,b->d,mont->N.d,mont->n0,num))
141 {
142 r->neg = a->neg^b->neg;
143 r->top = num;
144 bn_correct_top(r);
145 return(1);
146 }
147 }
148#endif
149
150 BN_CTX_start(ctx);
151 tmp = BN_CTX_get(ctx);
152 if (tmp == NULL) goto err;
153
154 bn_check_top(tmp);
155 if (a == b)
156 {
157 if (!BN_sqr(tmp,a,ctx)) goto err;
158 }
159 else
160 {
161 if (!BN_mul(tmp,a,b,ctx)) goto err;
162 }
163 /* reduce from aRR to aR */
164#ifdef MONT_WORD
165 if (!BN_from_montgomery_word(r,tmp,mont)) goto err;
166#else
167 if (!BN_from_montgomery(r,tmp,mont,ctx)) goto err;
168#endif
169 bn_check_top(r);
170 ret=1;
171err:
172 BN_CTX_end(ctx);
173 return(ret);
174 }
175
176#ifdef MONT_WORD
177static int BN_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont)
178 {
179 BIGNUM *n;
180 BN_ULONG *ap,*np,*rp,n0,v,*nrp;
181 int al,nl,max,i,x,ri;
182
183 n= &(mont->N);
184 /* mont->ri is the size of mont->N in bits (rounded up
185 to the word size) */
186 al=ri=mont->ri/BN_BITS2;
187
188 nl=n->top;
189 if ((al == 0) || (nl == 0)) { ret->top=0; return(1); }
190
191 max=(nl+al+1); /* allow for overflow (no?) XXX */
192 if (bn_wexpand(r,max) == NULL) return(0);
193
194 r->neg^=n->neg;
195 np=n->d;
196 rp=r->d;
197 nrp= &(r->d[nl]);
198
199 /* clear the top words of T */
200#if 1
201 for (i=r->top; i<max; i++) /* memset? XXX */
202 r->d[i]=0;
203#else
204 memset(&(r->d[r->top]),0,(max-r->top)*sizeof(BN_ULONG));
205#endif
206
207 r->top=max;
208 n0=mont->n0[0];
209
210#ifdef BN_COUNT
211 fprintf(stderr,"word BN_from_montgomery_word %d * %d\n",nl,nl);
212#endif
213 for (i=0; i<nl; i++)
214 {
215#ifdef __TANDEM
216 {
217 long long t1;
218 long long t2;
219 long long t3;
220 t1 = rp[0] * (n0 & 0177777);
221 t2 = 037777600000l;
222 t2 = n0 & t2;
223 t3 = rp[0] & 0177777;
224 t2 = (t3 * t2) & BN_MASK2;
225 t1 = t1 + t2;
226 v=bn_mul_add_words(rp,np,nl,(BN_ULONG) t1);
227 }
228#else
229 v=bn_mul_add_words(rp,np,nl,(rp[0]*n0)&BN_MASK2);
230#endif
231 nrp++;
232 rp++;
233 if (((nrp[-1]+=v)&BN_MASK2) >= v)
234 continue;
235 else
236 {
237 if (((++nrp[0])&BN_MASK2) != 0) continue;
238 if (((++nrp[1])&BN_MASK2) != 0) continue;
239 for (x=2; (((++nrp[x])&BN_MASK2) == 0); x++) ;
240 }
241 }
242 bn_correct_top(r);
243
244 /* mont->ri will be a multiple of the word size and below code
245 * is kind of BN_rshift(ret,r,mont->ri) equivalent */
246 if (r->top <= ri)
247 {
248 ret->top=0;
249 return(1);
250 }
251 al=r->top-ri;
252
253#define BRANCH_FREE 1
254#if BRANCH_FREE
255 if (bn_wexpand(ret,ri) == NULL) return(0);
256 x=0-(((al-ri)>>(sizeof(al)*8-1))&1);
257 ret->top=x=(ri&~x)|(al&x); /* min(ri,al) */
258 ret->neg=r->neg;
259
260 rp=ret->d;
261 ap=&(r->d[ri]);
262
263 {
264 size_t m1,m2;
265
266 v=bn_sub_words(rp,ap,np,ri);
267 /* this ----------------^^ works even in al<ri case
268 * thanks to zealous zeroing of top of the vector in the
269 * beginning. */
270
271 /* if (al==ri && !v) || al>ri) nrp=rp; else nrp=ap; */
272 /* in other words if subtraction result is real, then
273 * trick unconditional memcpy below to perform in-place
274 * "refresh" instead of actual copy. */
275 m1=0-(size_t)(((al-ri)>>(sizeof(al)*8-1))&1); /* al<ri */
276 m2=0-(size_t)(((ri-al)>>(sizeof(al)*8-1))&1); /* al>ri */
277 m1|=m2; /* (al!=ri) */
278 m1|=(0-(size_t)v); /* (al!=ri || v) */
279 m1&=~m2; /* (al!=ri || v) && !al>ri */
280 nrp=(BN_ULONG *)(((PTR_SIZE_INT)rp&~m1)|((PTR_SIZE_INT)ap&m1));
281 }
282
283 /* 'i<ri' is chosen to eliminate dependency on input data, even
284 * though it results in redundant copy in al<ri case. */
285 for (i=0,ri-=4; i<ri; i+=4)
286 {
287 BN_ULONG t1,t2,t3,t4;
288
289 t1=nrp[i+0];
290 t2=nrp[i+1];
291 t3=nrp[i+2]; ap[i+0]=0;
292 t4=nrp[i+3]; ap[i+1]=0;
293 rp[i+0]=t1; ap[i+2]=0;
294 rp[i+1]=t2; ap[i+3]=0;
295 rp[i+2]=t3;
296 rp[i+3]=t4;
297 }
298 for (ri+=4; i<ri; i++)
299 rp[i]=nrp[i], ap[i]=0;
300 bn_correct_top(r);
301 bn_correct_top(ret);
302#else
303 if (bn_wexpand(ret,al) == NULL) return(0);
304 ret->top=al;
305 ret->neg=r->neg;
306
307 rp=ret->d;
308 ap=&(r->d[ri]);
309 al-=4;
310 for (i=0; i<al; i+=4)
311 {
312 BN_ULONG t1,t2,t3,t4;
313
314 t1=ap[i+0];
315 t2=ap[i+1];
316 t3=ap[i+2];
317 t4=ap[i+3];
318 rp[i+0]=t1;
319 rp[i+1]=t2;
320 rp[i+2]=t3;
321 rp[i+3]=t4;
322 }
323 al+=4;
324 for (; i<al; i++)
325 rp[i]=ap[i];
326
327 if (BN_ucmp(ret, &(mont->N)) >= 0)
328 {
329 if (!BN_usub(ret,ret,&(mont->N))) return(0);
330 }
331#endif
332 bn_check_top(ret);
333
334 return(1);
335 }
336#endif /* MONT_WORD */
337
338int BN_from_montgomery(BIGNUM *ret, const BIGNUM *a, BN_MONT_CTX *mont,
339 BN_CTX *ctx)
340 {
341 int retn=0;
342#ifdef MONT_WORD
343 BIGNUM *t;
344
345 BN_CTX_start(ctx);
346 if ((t = BN_CTX_get(ctx)) && BN_copy(t,a))
347 retn = BN_from_montgomery_word(ret,t,mont);
348 BN_CTX_end(ctx);
349#else /* !MONT_WORD */
350 BIGNUM *t1,*t2;
351
352 BN_CTX_start(ctx);
353 t1 = BN_CTX_get(ctx);
354 t2 = BN_CTX_get(ctx);
355 if (t1 == NULL || t2 == NULL) goto err;
356
357 if (!BN_copy(t1,a)) goto err;
358 BN_mask_bits(t1,mont->ri);
359
360 if (!BN_mul(t2,t1,&mont->Ni,ctx)) goto err;
361 BN_mask_bits(t2,mont->ri);
362
363 if (!BN_mul(t1,t2,&mont->N,ctx)) goto err;
364 if (!BN_add(t2,a,t1)) goto err;
365 if (!BN_rshift(ret,t2,mont->ri)) goto err;
366
367 if (BN_ucmp(ret, &(mont->N)) >= 0)
368 {
369 if (!BN_usub(ret,ret,&(mont->N))) goto err;
370 }
371 retn=1;
372 bn_check_top(ret);
373 err:
374 BN_CTX_end(ctx);
375#endif /* MONT_WORD */
376 return(retn);
377 }
378
379BN_MONT_CTX *BN_MONT_CTX_new(void)
380 {
381 BN_MONT_CTX *ret;
382
383 if ((ret=(BN_MONT_CTX *)OPENSSL_malloc(sizeof(BN_MONT_CTX))) == NULL)
384 return(NULL);
385
386 BN_MONT_CTX_init(ret);
387 ret->flags=BN_FLG_MALLOCED;
388 return(ret);
389 }
390
391void BN_MONT_CTX_init(BN_MONT_CTX *ctx)
392 {
393 ctx->ri=0;
394 BN_init(&(ctx->RR));
395 BN_init(&(ctx->N));
396 BN_init(&(ctx->Ni));
397 ctx->n0[0] = ctx->n0[1] = 0;
398 ctx->flags=0;
399 }
400
401void BN_MONT_CTX_free(BN_MONT_CTX *mont)
402 {
403 if(mont == NULL)
404 return;
405
406 BN_free(&(mont->RR));
407 BN_free(&(mont->N));
408 BN_free(&(mont->Ni));
409 if (mont->flags & BN_FLG_MALLOCED)
410 OPENSSL_free(mont);
411 }
412
413int BN_MONT_CTX_set(BN_MONT_CTX *mont, const BIGNUM *mod, BN_CTX *ctx)
414 {
415 int ret = 0;
416 BIGNUM *Ri,*R;
417
418 BN_CTX_start(ctx);
419 if((Ri = BN_CTX_get(ctx)) == NULL) goto err;
420 R= &(mont->RR); /* grab RR as a temp */
421 if (!BN_copy(&(mont->N),mod)) goto err; /* Set N */
422 mont->N.neg = 0;
423
424#ifdef MONT_WORD
425 {
426 BIGNUM tmod;
427 BN_ULONG buf[2];
428
429 BN_init(&tmod);
430 tmod.d=buf;
431 tmod.dmax=2;
432 tmod.neg=0;
433
434 mont->ri=(BN_num_bits(mod)+(BN_BITS2-1))/BN_BITS2*BN_BITS2;
435
436#if defined(OPENSSL_BN_ASM_MONT) && (BN_BITS2<=32)
437 /* Only certain BN_BITS2<=32 platforms actually make use of
438 * n0[1], and we could use the #else case (with a shorter R
439 * value) for the others. However, currently only the assembler
440 * files do know which is which. */
441
442 BN_zero(R);
443 if (!(BN_set_bit(R,2*BN_BITS2))) goto err;
444
445 tmod.top=0;
446 if ((buf[0] = mod->d[0])) tmod.top=1;
447 if ((buf[1] = mod->top>1 ? mod->d[1] : 0)) tmod.top=2;
448
449 if ((BN_mod_inverse(Ri,R,&tmod,ctx)) == NULL)
450 goto err;
451 if (!BN_lshift(Ri,Ri,2*BN_BITS2)) goto err; /* R*Ri */
452 if (!BN_is_zero(Ri))
453 {
454 if (!BN_sub_word(Ri,1)) goto err;
455 }
456 else /* if N mod word size == 1 */
457 {
458 if (bn_expand(Ri,(int)sizeof(BN_ULONG)*2) == NULL)
459 goto err;
460 /* Ri-- (mod double word size) */
461 Ri->neg=0;
462 Ri->d[0]=BN_MASK2;
463 Ri->d[1]=BN_MASK2;
464 Ri->top=2;
465 }
466 if (!BN_div(Ri,NULL,Ri,&tmod,ctx)) goto err;
467 /* Ni = (R*Ri-1)/N,
468 * keep only couple of least significant words: */
469 mont->n0[0] = (Ri->top > 0) ? Ri->d[0] : 0;
470 mont->n0[1] = (Ri->top > 1) ? Ri->d[1] : 0;
471#else
472 BN_zero(R);
473 if (!(BN_set_bit(R,BN_BITS2))) goto err; /* R */
474
475 buf[0]=mod->d[0]; /* tmod = N mod word size */
476 buf[1]=0;
477 tmod.top = buf[0] != 0 ? 1 : 0;
478 /* Ri = R^-1 mod N*/
479 if ((BN_mod_inverse(Ri,R,&tmod,ctx)) == NULL)
480 goto err;
481 if (!BN_lshift(Ri,Ri,BN_BITS2)) goto err; /* R*Ri */
482 if (!BN_is_zero(Ri))
483 {
484 if (!BN_sub_word(Ri,1)) goto err;
485 }
486 else /* if N mod word size == 1 */
487 {
488 if (!BN_set_word(Ri,BN_MASK2)) goto err; /* Ri-- (mod word size) */
489 }
490 if (!BN_div(Ri,NULL,Ri,&tmod,ctx)) goto err;
491 /* Ni = (R*Ri-1)/N,
492 * keep only least significant word: */
493 mont->n0[0] = (Ri->top > 0) ? Ri->d[0] : 0;
494 mont->n0[1] = 0;
495#endif
496 }
497#else /* !MONT_WORD */
498 { /* bignum version */
499 mont->ri=BN_num_bits(&mont->N);
500 BN_zero(R);
501 if (!BN_set_bit(R,mont->ri)) goto err; /* R = 2^ri */
502 /* Ri = R^-1 mod N*/
503 if ((BN_mod_inverse(Ri,R,&mont->N,ctx)) == NULL)
504 goto err;
505 if (!BN_lshift(Ri,Ri,mont->ri)) goto err; /* R*Ri */
506 if (!BN_sub_word(Ri,1)) goto err;
507 /* Ni = (R*Ri-1) / N */
508 if (!BN_div(&(mont->Ni),NULL,Ri,&mont->N,ctx)) goto err;
509 }
510#endif
511
512 /* setup RR for conversions */
513 BN_zero(&(mont->RR));
514 if (!BN_set_bit(&(mont->RR),mont->ri*2)) goto err;
515 if (!BN_mod(&(mont->RR),&(mont->RR),&(mont->N),ctx)) goto err;
516
517 ret = 1;
518err:
519 BN_CTX_end(ctx);
520 return ret;
521 }
522
523BN_MONT_CTX *BN_MONT_CTX_copy(BN_MONT_CTX *to, BN_MONT_CTX *from)
524 {
525 if (to == from) return(to);
526
527 if (!BN_copy(&(to->RR),&(from->RR))) return NULL;
528 if (!BN_copy(&(to->N),&(from->N))) return NULL;
529 if (!BN_copy(&(to->Ni),&(from->Ni))) return NULL;
530 to->ri=from->ri;
531 to->n0[0]=from->n0[0];
532 to->n0[1]=from->n0[1];
533 return(to);
534 }
535
536BN_MONT_CTX *BN_MONT_CTX_set_locked(BN_MONT_CTX **pmont, int lock,
537 const BIGNUM *mod, BN_CTX *ctx)
538 {
539 int got_write_lock = 0;
540 BN_MONT_CTX *ret;
541
542 CRYPTO_r_lock(lock);
543 if (!*pmont)
544 {
545 CRYPTO_r_unlock(lock);
546 CRYPTO_w_lock(lock);
547 got_write_lock = 1;
548
549 if (!*pmont)
550 {
551 ret = BN_MONT_CTX_new();
552 if (ret && !BN_MONT_CTX_set(ret, mod, ctx))
553 BN_MONT_CTX_free(ret);
554 else
555 *pmont = ret;
556 }
557 }
558
559 ret = *pmont;
560
561 if (got_write_lock)
562 CRYPTO_w_unlock(lock);
563 else
564 CRYPTO_r_unlock(lock);
565
566 return ret;
567 }
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