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Diffstat (limited to 'src/lib/libcrypto/bn/bn_mont.c')
-rw-r--r--src/lib/libcrypto/bn/bn_mont.c313
1 files changed, 122 insertions, 191 deletions
diff --git a/src/lib/libcrypto/bn/bn_mont.c b/src/lib/libcrypto/bn/bn_mont.c
index ee0f410c22..7bb0b91223 100644
--- a/src/lib/libcrypto/bn/bn_mont.c
+++ b/src/lib/libcrypto/bn/bn_mont.c
@@ -57,25 +57,27 @@
57 */ 57 */
58 58
59/* 59/*
60 * Details about Montgomery multiplication algorithms can be found at: 60 * Details about Montgomery multiplication algorithms can be found at
61 * http://www.ece.orst.edu/ISL/Publications.html 61 * http://security.ece.orst.edu/publications.html, e.g.
62 * http://www.ece.orst.edu/ISL/Koc/papers/j37acmon.pdf 62 * http://security.ece.orst.edu/koc/papers/j37acmon.pdf and
63 * sections 3.8 and 4.2 in http://security.ece.orst.edu/koc/papers/r01rsasw.pdf
63 */ 64 */
64 65
65#include <stdio.h> 66#include <stdio.h>
66#include "cryptlib.h" 67#include "cryptlib.h"
67#include "bn_lcl.h" 68#include "bn_lcl.h"
68 69
69#define MONT_WORD 70#define MONT_WORD /* use the faster word-based algorithm */
70 71
71int BN_mod_mul_montgomery(BIGNUM *r, BIGNUM *a, BIGNUM *b, 72int BN_mod_mul_montgomery(BIGNUM *r, BIGNUM *a, BIGNUM *b,
72 BN_MONT_CTX *mont, BN_CTX *ctx) 73 BN_MONT_CTX *mont, BN_CTX *ctx)
73 { 74 {
74 BIGNUM *tmp,*tmp2; 75 BIGNUM *tmp,*tmp2;
75 76
76 tmp= &(ctx->bn[ctx->tos]); 77 BN_CTX_start(ctx);
77 tmp2= &(ctx->bn[ctx->tos]); 78 tmp = BN_CTX_get(ctx);
78 ctx->tos+=2; 79 tmp2 = BN_CTX_get(ctx);
80 if (tmp == NULL || tmp2 == NULL) goto err;
79 81
80 bn_check_top(tmp); 82 bn_check_top(tmp);
81 bn_check_top(tmp2); 83 bn_check_top(tmp2);
@@ -99,7 +101,7 @@ int BN_mod_mul_montgomery(BIGNUM *r, BIGNUM *a, BIGNUM *b,
99 } 101 }
100 /* reduce from aRR to aR */ 102 /* reduce from aRR to aR */
101 if (!BN_from_montgomery(r,tmp,mont,ctx)) goto err; 103 if (!BN_from_montgomery(r,tmp,mont,ctx)) goto err;
102 ctx->tos-=2; 104 BN_CTX_end(ctx);
103 return(1); 105 return(1);
104err: 106err:
105 return(0); 107 return(0);
@@ -108,160 +110,123 @@ err:
108int BN_from_montgomery(BIGNUM *ret, BIGNUM *a, BN_MONT_CTX *mont, 110int BN_from_montgomery(BIGNUM *ret, BIGNUM *a, BN_MONT_CTX *mont,
109 BN_CTX *ctx) 111 BN_CTX *ctx)
110 { 112 {
111#ifdef BN_RECURSION_MONT 113 int retn=0;
112 if (mont->use_word)
113#endif
114 {
115 BIGNUM *n,*r;
116 BN_ULONG *ap,*np,*rp,n0,v,*nrp;
117 int al,nl,max,i,x,ri;
118 int retn=0;
119 114
120 r= &(ctx->bn[ctx->tos]); 115#ifdef MONT_WORD
116 BIGNUM *n,*r;
117 BN_ULONG *ap,*np,*rp,n0,v,*nrp;
118 int al,nl,max,i,x,ri;
121 119
122 if (!BN_copy(r,a)) goto err1; 120 BN_CTX_start(ctx);
123 n= &(mont->N); 121 if ((r = BN_CTX_get(ctx)) == NULL) goto err;
124 122
125 ap=a->d; 123 if (!BN_copy(r,a)) goto err;
126 /* mont->ri is the size of mont->N in bits/words */ 124 n= &(mont->N);
127 al=ri=mont->ri/BN_BITS2;
128 125
129 nl=n->top; 126 ap=a->d;
130 if ((al == 0) || (nl == 0)) { r->top=0; return(1); } 127 /* mont->ri is the size of mont->N in bits (rounded up
128 to the word size) */
129 al=ri=mont->ri/BN_BITS2;
130
131 nl=n->top;
132 if ((al == 0) || (nl == 0)) { r->top=0; return(1); }
131 133
132 max=(nl+al+1); /* allow for overflow (no?) XXX */ 134 max=(nl+al+1); /* allow for overflow (no?) XXX */
133 if (bn_wexpand(r,max) == NULL) goto err1; 135 if (bn_wexpand(r,max) == NULL) goto err;
134 if (bn_wexpand(ret,max) == NULL) goto err1; 136 if (bn_wexpand(ret,max) == NULL) goto err;
135 137
136 r->neg=a->neg^n->neg; 138 r->neg=a->neg^n->neg;
137 np=n->d; 139 np=n->d;
138 rp=r->d; 140 rp=r->d;
139 nrp= &(r->d[nl]); 141 nrp= &(r->d[nl]);
140 142
141 /* clear the top words of T */ 143 /* clear the top words of T */
142#if 1 144#if 1
143 for (i=r->top; i<max; i++) /* memset? XXX */ 145 for (i=r->top; i<max; i++) /* memset? XXX */
144 r->d[i]=0; 146 r->d[i]=0;
145#else 147#else
146 memset(&(r->d[r->top]),0,(max-r->top)*sizeof(BN_ULONG)); 148 memset(&(r->d[r->top]),0,(max-r->top)*sizeof(BN_ULONG));
147#endif 149#endif
148 150
149 r->top=max; 151 r->top=max;
150 n0=mont->n0; 152 n0=mont->n0;
151 153
152#ifdef BN_COUNT 154#ifdef BN_COUNT
153printf("word BN_from_montgomery %d * %d\n",nl,nl); 155 printf("word BN_from_montgomery %d * %d\n",nl,nl);
154#endif 156#endif
155 for (i=0; i<nl; i++) 157 for (i=0; i<nl; i++)
156 { 158 {
157 v=bn_mul_add_words(rp,np,nl,(rp[0]*n0)&BN_MASK2); 159 v=bn_mul_add_words(rp,np,nl,(rp[0]*n0)&BN_MASK2);
158 nrp++; 160 nrp++;
159 rp++; 161 rp++;
160 if (((nrp[-1]+=v)&BN_MASK2) >= v) 162 if (((nrp[-1]+=v)&BN_MASK2) >= v)
161 continue; 163 continue;
162 else
163 {
164 if (((++nrp[0])&BN_MASK2) != 0) continue;
165 if (((++nrp[1])&BN_MASK2) != 0) continue;
166 for (x=2; (((++nrp[x])&BN_MASK2) == 0); x++) ;
167 }
168 }
169 bn_fix_top(r);
170
171 /* mont->ri will be a multiple of the word size */
172#if 0
173 BN_rshift(ret,r,mont->ri);
174#else
175 x=ri;
176 rp=ret->d;
177 ap= &(r->d[x]);
178 if (r->top < x)
179 al=0;
180 else 164 else
181 al=r->top-x;
182 ret->top=al;
183 al-=4;
184 for (i=0; i<al; i+=4)
185 { 165 {
186 BN_ULONG t1,t2,t3,t4; 166 if (((++nrp[0])&BN_MASK2) != 0) continue;
187 167 if (((++nrp[1])&BN_MASK2) != 0) continue;
188 t1=ap[i+0]; 168 for (x=2; (((++nrp[x])&BN_MASK2) == 0); x++) ;
189 t2=ap[i+1];
190 t3=ap[i+2];
191 t4=ap[i+3];
192 rp[i+0]=t1;
193 rp[i+1]=t2;
194 rp[i+2]=t3;
195 rp[i+3]=t4;
196 } 169 }
197 al+=4;
198 for (; i<al; i++)
199 rp[i]=ap[i];
200#endif
201
202 if (BN_ucmp(ret, &(mont->N)) >= 0)
203 {
204 BN_usub(ret,ret,&(mont->N)); /* XXX */
205 }
206 retn=1;
207err1:
208 return(retn);
209 } 170 }
210#ifdef BN_RECURSION_MONT 171 bn_fix_top(r);
211 else /* bignum version */ 172
173 /* mont->ri will be a multiple of the word size */
174#if 0
175 BN_rshift(ret,r,mont->ri);
176#else
177 x=ri;
178 rp=ret->d;
179 ap= &(r->d[x]);
180 if (r->top < x)
181 al=0;
182 else
183 al=r->top-x;
184 ret->top=al;
185 al-=4;
186 for (i=0; i<al; i+=4)
212 { 187 {
213 BIGNUM *t1,*t2,*t3; 188 BN_ULONG t1,t2,t3,t4;
214 int j,i; 189
215 190 t1=ap[i+0];
216#ifdef BN_COUNT 191 t2=ap[i+1];
217printf("number BN_from_montgomery\n"); 192 t3=ap[i+2];
218#endif 193 t4=ap[i+3];
219 194 rp[i+0]=t1;
220 t1= &(ctx->bn[ctx->tos]); 195 rp[i+1]=t2;
221 t2= &(ctx->bn[ctx->tos+1]); 196 rp[i+2]=t3;
222 t3= &(ctx->bn[ctx->tos+2]); 197 rp[i+3]=t4;
223
224 i=mont->Ni.top;
225 bn_wexpand(ret,i); /* perhaps only i*2 */
226 bn_wexpand(t1,i*4); /* perhaps only i*2 */
227 bn_wexpand(t2,i*2); /* perhaps only i */
228
229 bn_mul_low_recursive(t2->d,a->d,mont->Ni.d,i,t1->d);
230
231 BN_zero(t3);
232 BN_set_bit(t3,mont->N.top*BN_BITS2);
233 bn_sub_words(t3->d,t3->d,a->d,i);
234 bn_mul_high(ret->d,t2->d,mont->N.d,t3->d,i,t1->d);
235
236 /* hmm... if a is between i and 2*i, things are bad */
237 if (a->top > i)
238 {
239 j=(int)(bn_add_words(ret->d,ret->d,&(a->d[i]),i));
240 if (j) /* overflow */
241 bn_sub_words(ret->d,ret->d,mont->N.d,i);
242 }
243 ret->top=i;
244 bn_fix_top(ret);
245 if (a->d[0])
246 BN_add_word(ret,1); /* Always? */
247 else /* Very very rare */
248 {
249 for (i=1; i<mont->N.top-1; i++)
250 {
251 if (a->d[i])
252 {
253 BN_add_word(ret,1); /* Always? */
254 break;
255 }
256 }
257 }
258
259 if (BN_ucmp(ret,&(mont->N)) >= 0)
260 BN_usub(ret,ret,&(mont->N));
261
262 return(1);
263 } 198 }
199 al+=4;
200 for (; i<al; i++)
201 rp[i]=ap[i];
264#endif 202#endif
203#else /* !MONT_WORD */
204 BIGNUM *t1,*t2;
205
206 BN_CTX_start(ctx);
207 t1 = BN_CTX_get(ctx);
208 t2 = BN_CTX_get(ctx);
209 if (t1 == NULL || t2 == NULL) goto err;
210
211 if (!BN_copy(t1,a)) goto err;
212 BN_mask_bits(t1,mont->ri);
213
214 if (!BN_mul(t2,t1,&mont->Ni,ctx)) goto err;
215 BN_mask_bits(t2,mont->ri);
216
217 if (!BN_mul(t1,t2,&mont->N,ctx)) goto err;
218 if (!BN_add(t2,a,t1)) goto err;
219 BN_rshift(ret,t2,mont->ri);
220#endif /* MONT_WORD */
221
222 if (BN_ucmp(ret, &(mont->N)) >= 0)
223 {
224 BN_usub(ret,ret,&(mont->N));
225 }
226 retn=1;
227 err:
228 BN_CTX_end(ctx);
229 return(retn);
265 } 230 }
266 231
267BN_MONT_CTX *BN_MONT_CTX_new(void) 232BN_MONT_CTX *BN_MONT_CTX_new(void)
@@ -278,7 +243,6 @@ BN_MONT_CTX *BN_MONT_CTX_new(void)
278 243
279void BN_MONT_CTX_init(BN_MONT_CTX *ctx) 244void BN_MONT_CTX_init(BN_MONT_CTX *ctx)
280 { 245 {
281 ctx->use_word=0;
282 ctx->ri=0; 246 ctx->ri=0;
283 BN_init(&(ctx->RR)); 247 BN_init(&(ctx->RR));
284 BN_init(&(ctx->N)); 248 BN_init(&(ctx->N));
@@ -306,85 +270,53 @@ int BN_MONT_CTX_set(BN_MONT_CTX *mont, const BIGNUM *mod, BN_CTX *ctx)
306 R= &(mont->RR); /* grab RR as a temp */ 270 R= &(mont->RR); /* grab RR as a temp */
307 BN_copy(&(mont->N),mod); /* Set N */ 271 BN_copy(&(mont->N),mod); /* Set N */
308 272
309#ifdef BN_RECURSION_MONT 273#ifdef MONT_WORD
310 if (mont->N.top < BN_MONT_CTX_SET_SIZE_WORD)
311#endif
312 { 274 {
313 BIGNUM tmod; 275 BIGNUM tmod;
314 BN_ULONG buf[2]; 276 BN_ULONG buf[2];
315 277
316 mont->use_word=1;
317
318 mont->ri=(BN_num_bits(mod)+(BN_BITS2-1))/BN_BITS2*BN_BITS2; 278 mont->ri=(BN_num_bits(mod)+(BN_BITS2-1))/BN_BITS2*BN_BITS2;
319 BN_zero(R); 279 BN_zero(R);
320 BN_set_bit(R,BN_BITS2); 280 BN_set_bit(R,BN_BITS2); /* R */
321 /* I was bad, this modification of a passed variable was
322 * breaking the multithreaded stuff :-(
323 * z=mod->top;
324 * mod->top=1; */
325 281
326 buf[0]=mod->d[0]; 282 buf[0]=mod->d[0]; /* tmod = N mod word size */
327 buf[1]=0; 283 buf[1]=0;
328 tmod.d=buf; 284 tmod.d=buf;
329 tmod.top=1; 285 tmod.top=1;
330 tmod.max=mod->max; 286 tmod.max=2;
331 tmod.neg=mod->neg; 287 tmod.neg=mod->neg;
332 288 /* Ri = R^-1 mod N*/
333 if ((BN_mod_inverse(&Ri,R,&tmod,ctx)) == NULL) 289 if ((BN_mod_inverse(&Ri,R,&tmod,ctx)) == NULL)
334 goto err; 290 goto err;
335 BN_lshift(&Ri,&Ri,BN_BITS2); /* R*Ri */ 291 BN_lshift(&Ri,&Ri,BN_BITS2); /* R*Ri */
336 if (!BN_is_zero(&Ri)) 292 if (!BN_is_zero(&Ri))
337 {
338#if 1
339 BN_sub_word(&Ri,1); 293 BN_sub_word(&Ri,1);
340#else 294 else /* if N mod word size == 1 */
341 BN_usub(&Ri,&Ri,BN_value_one()); /* R*Ri - 1 */ 295 BN_set_word(&Ri,BN_MASK2); /* Ri-- (mod word size) */
342#endif 296 BN_div(&Ri,NULL,&Ri,&tmod,ctx); /* Ni = (R*Ri-1)/N,
343 } 297 * keep only least significant word: */
344 else
345 {
346 /* This is not common..., 1 in BN_MASK2,
347 * It happens when buf[0] was == 1. So for 8 bit,
348 * this is 1/256, 16bit, 1 in 2^16 etc.
349 */
350 BN_set_word(&Ri,BN_MASK2);
351 }
352 BN_div(&Ri,NULL,&Ri,&tmod,ctx);
353 mont->n0=Ri.d[0]; 298 mont->n0=Ri.d[0];
354 BN_free(&Ri); 299 BN_free(&Ri);
355 /* mod->top=z; */
356 } 300 }
357#ifdef BN_RECURSION_MONT 301#else /* !MONT_WORD */
358 else 302 { /* bignum version */
359 { 303 mont->ri=BN_num_bits(mod);
360 mont->use_word=0;
361 mont->ri=(BN_num_bits(mod)+(BN_BITS2-1))/BN_BITS2*BN_BITS2;
362#if 1
363 BN_zero(R); 304 BN_zero(R);
364 BN_set_bit(R,mont->ri); 305 BN_set_bit(R,mont->ri); /* R = 2^ri */
365#else 306 /* Ri = R^-1 mod N*/
366 BN_lshift(R,BN_value_one(),mont->ri); /* R */
367#endif
368 if ((BN_mod_inverse(&Ri,R,mod,ctx)) == NULL) 307 if ((BN_mod_inverse(&Ri,R,mod,ctx)) == NULL)
369 goto err; 308 goto err;
370 BN_lshift(&Ri,&Ri,mont->ri); /* R*Ri */ 309 BN_lshift(&Ri,&Ri,mont->ri); /* R*Ri */
371#if 1
372 BN_sub_word(&Ri,1); 310 BN_sub_word(&Ri,1);
373#else 311 /* Ni = (R*Ri-1) / N */
374 BN_usub(&Ri,&Ri,BN_value_one()); /* R*Ri - 1 */
375#endif
376 BN_div(&(mont->Ni),NULL,&Ri,mod,ctx); 312 BN_div(&(mont->Ni),NULL,&Ri,mod,ctx);
377 BN_free(&Ri); 313 BN_free(&Ri);
378 } 314 }
379#endif 315#endif
380 316
381 /* setup RR for conversions */ 317 /* setup RR for conversions */
382#if 1
383 BN_zero(&(mont->RR)); 318 BN_zero(&(mont->RR));
384 BN_set_bit(&(mont->RR),mont->ri*2); 319 BN_set_bit(&(mont->RR),mont->ri*2);
385#else
386 BN_lshift(mont->RR,BN_value_one(),mont->ri*2);
387#endif
388 BN_mod(&(mont->RR),&(mont->RR),&(mont->N),ctx); 320 BN_mod(&(mont->RR),&(mont->RR),&(mont->N),ctx);
389 321
390 return(1); 322 return(1);
@@ -399,7 +331,6 @@ BN_MONT_CTX *BN_MONT_CTX_copy(BN_MONT_CTX *to, BN_MONT_CTX *from)
399 BN_copy(&(to->RR),&(from->RR)); 331 BN_copy(&(to->RR),&(from->RR));
400 BN_copy(&(to->N),&(from->N)); 332 BN_copy(&(to->N),&(from->N));
401 BN_copy(&(to->Ni),&(from->Ni)); 333 BN_copy(&(to->Ni),&(from->Ni));
402 to->use_word=from->use_word;
403 to->ri=from->ri; 334 to->ri=from->ri;
404 to->n0=from->n0; 335 to->n0=from->n0;
405 return(to); 336 return(to);
generated by cgit v1.2.3-55-g6feb (git 2.39.1) at 2025-08-05 01:26:04 +0000