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OpenSSL: update to 1.0.2c
[tomato.git] / release / src / router / openssl / crypto / ec / ecp_nistz256.c
blobca44d0aaeec4517593996e34a5cb2a29e8987ef1
1 /******************************************************************************
2 * *
3 * Copyright 2014 Intel Corporation *
4 * *
5 * Licensed under the Apache License, Version 2.0 (the "License"); *
6 * you may not use this file except in compliance with the License. *
7 * You may obtain a copy of the License at *
8 * *
9 * http://www.apache.org/licenses/LICENSE-2.0 *
10 * *
11 * Unless required by applicable law or agreed to in writing, software *
12 * distributed under the License is distributed on an "AS IS" BASIS, *
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. *
14 * See the License for the specific language governing permissions and *
15 * limitations under the License. *
16 * *
17 ******************************************************************************
18 * *
19 * Developers and authors: *
20 * Shay Gueron (1, 2), and Vlad Krasnov (1) *
21 * (1) Intel Corporation, Israel Development Center *
22 * (2) University of Haifa *
23 * Reference: *
24 * S.Gueron and V.Krasnov, "Fast Prime Field Elliptic Curve Cryptography with *
25 * 256 Bit Primes" *
26 * *
27 ******************************************************************************/
28
29 #include <string.h>
30
31 #include <openssl/bn.h>
32 #include <openssl/err.h>
33 #include <openssl/ec.h>
34 #include "cryptlib.h"
35
36 #include "ec_lcl.h"
37
38 #if BN_BITS2 != 64
39 # define TOBN(hi,lo) lo,hi
40 #else
41 # define TOBN(hi,lo) ((BN_ULONG)hi<<32|lo)
42 #endif
43
44 #if defined(__GNUC__)
45 # define ALIGN32 __attribute((aligned(32)))
46 #elif defined(_MSC_VER)
47 # define ALIGN32 __declspec(align(32))
48 #else
49 # define ALIGN32
50 #endif
51
52 #define ALIGNPTR(p,N) ((unsigned char *)p+N-(size_t)p%N)
53 #define P256_LIMBS (256/BN_BITS2)
54
55 typedef unsigned short u16;
56
57 typedef struct {
58 BN_ULONG X[P256_LIMBS];
59 BN_ULONG Y[P256_LIMBS];
60 BN_ULONG Z[P256_LIMBS];
61 } P256_POINT;
62
63 typedef struct {
64 BN_ULONG X[P256_LIMBS];
65 BN_ULONG Y[P256_LIMBS];
66 } P256_POINT_AFFINE;
67
68 typedef P256_POINT_AFFINE PRECOMP256_ROW[64];
69
70 /* structure for precomputed multiples of the generator */
71 typedef struct ec_pre_comp_st {
72 const EC_GROUP *group; /* Parent EC_GROUP object */
73 size_t w; /* Window size */
74 /*
75 * Constant time access to the X and Y coordinates of the pre-computed,
76 * generator multiplies, in the Montgomery domain. Pre-calculated
77 * multiplies are stored in affine form.
78 */
79 PRECOMP256_ROW *precomp;
80 void *precomp_storage;
81 int references;
82 } EC_PRE_COMP;
83
84 /* Functions implemented in assembly */
85 /* Modular mul by 2: res = 2*a mod P */
86 void ecp_nistz256_mul_by_2(BN_ULONG res[P256_LIMBS],
87 const BN_ULONG a[P256_LIMBS]);
88 /* Modular div by 2: res = a/2 mod P */
89 void ecp_nistz256_div_by_2(BN_ULONG res[P256_LIMBS],
90 const BN_ULONG a[P256_LIMBS]);
91 /* Modular mul by 3: res = 3*a mod P */
92 void ecp_nistz256_mul_by_3(BN_ULONG res[P256_LIMBS],
93 const BN_ULONG a[P256_LIMBS]);
94 /* Modular add: res = a+b mod P */
95 void ecp_nistz256_add(BN_ULONG res[P256_LIMBS],
96 const BN_ULONG a[P256_LIMBS],
97 const BN_ULONG b[P256_LIMBS]);
98 /* Modular sub: res = a-b mod P */
99 void ecp_nistz256_sub(BN_ULONG res[P256_LIMBS],
100 const BN_ULONG a[P256_LIMBS],
101 const BN_ULONG b[P256_LIMBS]);
102 /* Modular neg: res = -a mod P */
103 void ecp_nistz256_neg(BN_ULONG res[P256_LIMBS], const BN_ULONG a[P256_LIMBS]);
104 /* Montgomery mul: res = a*b*2^-256 mod P */
105 void ecp_nistz256_mul_mont(BN_ULONG res[P256_LIMBS],
106 const BN_ULONG a[P256_LIMBS],
107 const BN_ULONG b[P256_LIMBS]);
108 /* Montgomery sqr: res = a*a*2^-256 mod P */
109 void ecp_nistz256_sqr_mont(BN_ULONG res[P256_LIMBS],
110 const BN_ULONG a[P256_LIMBS]);
111 /* Convert a number from Montgomery domain, by multiplying with 1 */
112 void ecp_nistz256_from_mont(BN_ULONG res[P256_LIMBS],
113 const BN_ULONG in[P256_LIMBS]);
114 /* Convert a number to Montgomery domain, by multiplying with 2^512 mod P*/
115 void ecp_nistz256_to_mont(BN_ULONG res[P256_LIMBS],
116 const BN_ULONG in[P256_LIMBS]);
117 /* Functions that perform constant time access to the precomputed tables */
118 void ecp_nistz256_select_w5(P256_POINT * val,
119 const P256_POINT * in_t, int index);
120 void ecp_nistz256_select_w7(P256_POINT_AFFINE * val,
121 const P256_POINT_AFFINE * in_t, int index);
122
123 /* One converted into the Montgomery domain */
124 static const BN_ULONG ONE[P256_LIMBS] = {
125 TOBN(0x00000000, 0x00000001), TOBN(0xffffffff, 0x00000000),
126 TOBN(0xffffffff, 0xffffffff), TOBN(0x00000000, 0xfffffffe)
127 };
128
129 static void *ecp_nistz256_pre_comp_dup(void *);
130 static void ecp_nistz256_pre_comp_free(void *);
131 static void ecp_nistz256_pre_comp_clear_free(void *);
132 static EC_PRE_COMP *ecp_nistz256_pre_comp_new(const EC_GROUP *group);
133
134 /* Precomputed tables for the default generator */
135 #include "ecp_nistz256_table.c"
136
137 /* Recode window to a signed digit, see ecp_nistputil.c for details */
138 static unsigned int _booth_recode_w5(unsigned int in)
139 {
140 unsigned int s, d;
141
142 s = ~((in >> 5) - 1);
143 d = (1 << 6) - in - 1;
144 d = (d & s) | (in & ~s);
145 d = (d >> 1) + (d & 1);
146
147 return (d << 1) + (s & 1);
148 }
149
150 static unsigned int _booth_recode_w7(unsigned int in)
151 {
152 unsigned int s, d;
153
154 s = ~((in >> 7) - 1);
155 d = (1 << 8) - in - 1;
156 d = (d & s) | (in & ~s);
157 d = (d >> 1) + (d & 1);
158
159 return (d << 1) + (s & 1);
160 }
161
162 static void copy_conditional(BN_ULONG dst[P256_LIMBS],
163 const BN_ULONG src[P256_LIMBS], BN_ULONG move)
164 {
165 BN_ULONG mask1 = -move;
166 BN_ULONG mask2 = ~mask1;
167
168 dst[0] = (src[0] & mask1) ^ (dst[0] & mask2);
169 dst[1] = (src[1] & mask1) ^ (dst[1] & mask2);
170 dst[2] = (src[2] & mask1) ^ (dst[2] & mask2);
171 dst[3] = (src[3] & mask1) ^ (dst[3] & mask2);
172 if (P256_LIMBS == 8) {
173 dst[4] = (src[4] & mask1) ^ (dst[4] & mask2);
174 dst[5] = (src[5] & mask1) ^ (dst[5] & mask2);
175 dst[6] = (src[6] & mask1) ^ (dst[6] & mask2);
176 dst[7] = (src[7] & mask1) ^ (dst[7] & mask2);
177 }
178 }
179
180 static BN_ULONG is_zero(BN_ULONG in)
181 {
182 in |= (0 - in);
183 in = ~in;
184 in &= BN_MASK2;
185 in >>= BN_BITS2 - 1;
186 return in;
187 }
188
189 static BN_ULONG is_equal(const BN_ULONG a[P256_LIMBS],
190 const BN_ULONG b[P256_LIMBS])
191 {
192 BN_ULONG res;
193
194 res = a[0] ^ b[0];
195 res |= a[1] ^ b[1];
196 res |= a[2] ^ b[2];
197 res |= a[3] ^ b[3];
198 if (P256_LIMBS == 8) {
199 res |= a[4] ^ b[4];
200 res |= a[5] ^ b[5];
201 res |= a[6] ^ b[6];
202 res |= a[7] ^ b[7];
203 }
204
205 return is_zero(res);
206 }
207
208 static BN_ULONG is_one(const BN_ULONG a[P256_LIMBS])
209 {
210 BN_ULONG res;
211
212 res = a[0] ^ ONE[0];
213 res |= a[1] ^ ONE[1];
214 res |= a[2] ^ ONE[2];
215 res |= a[3] ^ ONE[3];
216 if (P256_LIMBS == 8) {
217 res |= a[4] ^ ONE[4];
218 res |= a[5] ^ ONE[5];
219 res |= a[6] ^ ONE[6];
220 }
221
222 return is_zero(res);
223 }
224
225 static int ecp_nistz256_set_words(BIGNUM *a, BN_ULONG words[P256_LIMBS])
226 {
227 if (bn_wexpand(a, P256_LIMBS) == NULL) {
228 ECerr(EC_F_ECP_NISTZ256_SET_WORDS, ERR_R_MALLOC_FAILURE);
229 return 0;
230 }
231 memcpy(a->d, words, sizeof(BN_ULONG) * P256_LIMBS);
232 a->top = P256_LIMBS;
233 bn_correct_top(a);
234 return 1;
235 }
236
237 #ifndef ECP_NISTZ256_REFERENCE_IMPLEMENTATION
238 void ecp_nistz256_point_double(P256_POINT *r, const P256_POINT *a);
239 void ecp_nistz256_point_add(P256_POINT *r,
240 const P256_POINT *a, const P256_POINT *b);
241 void ecp_nistz256_point_add_affine(P256_POINT *r,
242 const P256_POINT *a,
243 const P256_POINT_AFFINE *b);
244 #else
245 /* Point double: r = 2*a */
246 static void ecp_nistz256_point_double(P256_POINT *r, const P256_POINT *a)
247 {
248 BN_ULONG S[P256_LIMBS];
249 BN_ULONG M[P256_LIMBS];
250 BN_ULONG Zsqr[P256_LIMBS];
251 BN_ULONG tmp0[P256_LIMBS];
252
253 const BN_ULONG *in_x = a->X;
254 const BN_ULONG *in_y = a->Y;
255 const BN_ULONG *in_z = a->Z;
256
257 BN_ULONG *res_x = r->X;
258 BN_ULONG *res_y = r->Y;
259 BN_ULONG *res_z = r->Z;
260
261 ecp_nistz256_mul_by_2(S, in_y);
262
263 ecp_nistz256_sqr_mont(Zsqr, in_z);
264
265 ecp_nistz256_sqr_mont(S, S);
266
267 ecp_nistz256_mul_mont(res_z, in_z, in_y);
268 ecp_nistz256_mul_by_2(res_z, res_z);
269
270 ecp_nistz256_add(M, in_x, Zsqr);
271 ecp_nistz256_sub(Zsqr, in_x, Zsqr);
272
273 ecp_nistz256_sqr_mont(res_y, S);
274 ecp_nistz256_div_by_2(res_y, res_y);
275
276 ecp_nistz256_mul_mont(M, M, Zsqr);
277 ecp_nistz256_mul_by_3(M, M);
278
279 ecp_nistz256_mul_mont(S, S, in_x);
280 ecp_nistz256_mul_by_2(tmp0, S);
281
282 ecp_nistz256_sqr_mont(res_x, M);
283
284 ecp_nistz256_sub(res_x, res_x, tmp0);
285 ecp_nistz256_sub(S, S, res_x);
286
287 ecp_nistz256_mul_mont(S, S, M);
288 ecp_nistz256_sub(res_y, S, res_y);
289 }
290
291 /* Point addition: r = a+b */
292 static void ecp_nistz256_point_add(P256_POINT *r,
293 const P256_POINT *a, const P256_POINT *b)
294 {
295 BN_ULONG U2[P256_LIMBS], S2[P256_LIMBS];
296 BN_ULONG U1[P256_LIMBS], S1[P256_LIMBS];
297 BN_ULONG Z1sqr[P256_LIMBS];
298 BN_ULONG Z2sqr[P256_LIMBS];
299 BN_ULONG H[P256_LIMBS], R[P256_LIMBS];
300 BN_ULONG Hsqr[P256_LIMBS];
301 BN_ULONG Rsqr[P256_LIMBS];
302 BN_ULONG Hcub[P256_LIMBS];
303
304 BN_ULONG res_x[P256_LIMBS];
305 BN_ULONG res_y[P256_LIMBS];
306 BN_ULONG res_z[P256_LIMBS];
307
308 BN_ULONG in1infty, in2infty;
309
310 const BN_ULONG *in1_x = a->X;
311 const BN_ULONG *in1_y = a->Y;
312 const BN_ULONG *in1_z = a->Z;
313
314 const BN_ULONG *in2_x = b->X;
315 const BN_ULONG *in2_y = b->Y;
316 const BN_ULONG *in2_z = b->Z;
317
318 /* We encode infinity as (0,0), which is not on the curve,
319 * so it is OK. */
320 in1infty = (in1_x[0] | in1_x[1] | in1_x[2] | in1_x[3] |
321 in1_y[0] | in1_y[1] | in1_y[2] | in1_y[3]);
322 if (P256_LIMBS == 8)
323 in1infty |= (in1_x[4] | in1_x[5] | in1_x[6] | in1_x[7] |
324 in1_y[4] | in1_y[5] | in1_y[6] | in1_y[7]);
325
326 in2infty = (in2_x[0] | in2_x[1] | in2_x[2] | in2_x[3] |
327 in2_y[0] | in2_y[1] | in2_y[2] | in2_y[3]);
328 if (P256_LIMBS == 8)
329 in2infty |= (in2_x[4] | in2_x[5] | in2_x[6] | in2_x[7] |
330 in2_y[4] | in2_y[5] | in2_y[6] | in2_y[7]);
331
332 in1infty = is_zero(in1infty);
333 in2infty = is_zero(in2infty);
334
335 ecp_nistz256_sqr_mont(Z2sqr, in2_z); /* Z2^2 */
336 ecp_nistz256_sqr_mont(Z1sqr, in1_z); /* Z1^2 */
337
338 ecp_nistz256_mul_mont(S1, Z2sqr, in2_z); /* S1 = Z2^3 */
339 ecp_nistz256_mul_mont(S2, Z1sqr, in1_z); /* S2 = Z1^3 */
340
341 ecp_nistz256_mul_mont(S1, S1, in1_y); /* S1 = Y1*Z2^3 */
342 ecp_nistz256_mul_mont(S2, S2, in2_y); /* S2 = Y2*Z1^3 */
343 ecp_nistz256_sub(R, S2, S1); /* R = S2 - S1 */
344
345 ecp_nistz256_mul_mont(U1, in1_x, Z2sqr); /* U1 = X1*Z2^2 */
346 ecp_nistz256_mul_mont(U2, in2_x, Z1sqr); /* U2 = X2*Z1^2 */
347 ecp_nistz256_sub(H, U2, U1); /* H = U2 - U1 */
348
349 /*
350 * This should not happen during sign/ecdh, so no constant time violation
351 */
352 if (is_equal(U1, U2) && !in1infty && !in2infty) {
353 if (is_equal(S1, S2)) {
354 ecp_nistz256_point_double(r, a);
355 return;
356 } else {
357 memset(r, 0, sizeof(*r));
358 return;
359 }
360 }
361
362 ecp_nistz256_sqr_mont(Rsqr, R); /* R^2 */
363 ecp_nistz256_mul_mont(res_z, H, in1_z); /* Z3 = H*Z1*Z2 */
364 ecp_nistz256_sqr_mont(Hsqr, H); /* H^2 */
365 ecp_nistz256_mul_mont(res_z, res_z, in2_z); /* Z3 = H*Z1*Z2 */
366 ecp_nistz256_mul_mont(Hcub, Hsqr, H); /* H^3 */
367
368 ecp_nistz256_mul_mont(U2, U1, Hsqr); /* U1*H^2 */
369 ecp_nistz256_mul_by_2(Hsqr, U2); /* 2*U1*H^2 */
370
371 ecp_nistz256_sub(res_x, Rsqr, Hsqr);
372 ecp_nistz256_sub(res_x, res_x, Hcub);
373
374 ecp_nistz256_sub(res_y, U2, res_x);
375
376 ecp_nistz256_mul_mont(S2, S1, Hcub);
377 ecp_nistz256_mul_mont(res_y, R, res_y);
378 ecp_nistz256_sub(res_y, res_y, S2);
379
380 copy_conditional(res_x, in2_x, in1infty);
381 copy_conditional(res_y, in2_y, in1infty);
382 copy_conditional(res_z, in2_z, in1infty);
383
384 copy_conditional(res_x, in1_x, in2infty);
385 copy_conditional(res_y, in1_y, in2infty);
386 copy_conditional(res_z, in1_z, in2infty);
387
388 memcpy(r->X, res_x, sizeof(res_x));
389 memcpy(r->Y, res_y, sizeof(res_y));
390 memcpy(r->Z, res_z, sizeof(res_z));
391 }
392
393 /* Point addition when b is known to be affine: r = a+b */
394 static void ecp_nistz256_point_add_affine(P256_POINT *r,
395 const P256_POINT *a,
396 const P256_POINT_AFFINE *b)
397 {
398 BN_ULONG U2[P256_LIMBS], S2[P256_LIMBS];
399 BN_ULONG Z1sqr[P256_LIMBS];
400 BN_ULONG H[P256_LIMBS], R[P256_LIMBS];
401 BN_ULONG Hsqr[P256_LIMBS];
402 BN_ULONG Rsqr[P256_LIMBS];
403 BN_ULONG Hcub[P256_LIMBS];
404
405 BN_ULONG res_x[P256_LIMBS];
406 BN_ULONG res_y[P256_LIMBS];
407 BN_ULONG res_z[P256_LIMBS];
408
409 BN_ULONG in1infty, in2infty;
410
411 const BN_ULONG *in1_x = a->X;
412 const BN_ULONG *in1_y = a->Y;
413 const BN_ULONG *in1_z = a->Z;
414
415 const BN_ULONG *in2_x = b->X;
416 const BN_ULONG *in2_y = b->Y;
417
418 /*
419 * In affine representation we encode infty as (0,0), which is not on the
420 * curve, so it is OK
421 */
422 in1infty = (in1_x[0] | in1_x[1] | in1_x[2] | in1_x[3] |
423 in1_y[0] | in1_y[1] | in1_y[2] | in1_y[3]);
424 if (P256_LIMBS == 8)
425 in1infty |= (in1_x[4] | in1_x[5] | in1_x[6] | in1_x[7] |
426 in1_y[4] | in1_y[5] | in1_y[6] | in1_y[7]);
427
428 in2infty = (in2_x[0] | in2_x[1] | in2_x[2] | in2_x[3] |
429 in2_y[0] | in2_y[1] | in2_y[2] | in2_y[3]);
430 if (P256_LIMBS == 8)
431 in2infty |= (in2_x[4] | in2_x[5] | in2_x[6] | in2_x[7] |
432 in2_y[4] | in2_y[5] | in2_y[6] | in2_y[7]);
433
434 in1infty = is_zero(in1infty);
435 in2infty = is_zero(in2infty);
436
437 ecp_nistz256_sqr_mont(Z1sqr, in1_z); /* Z1^2 */
438
439 ecp_nistz256_mul_mont(U2, in2_x, Z1sqr); /* U2 = X2*Z1^2 */
440 ecp_nistz256_sub(H, U2, in1_x); /* H = U2 - U1 */
441
442 ecp_nistz256_mul_mont(S2, Z1sqr, in1_z); /* S2 = Z1^3 */
443
444 ecp_nistz256_mul_mont(res_z, H, in1_z); /* Z3 = H*Z1*Z2 */
445
446 ecp_nistz256_mul_mont(S2, S2, in2_y); /* S2 = Y2*Z1^3 */
447 ecp_nistz256_sub(R, S2, in1_y); /* R = S2 - S1 */
448
449 ecp_nistz256_sqr_mont(Hsqr, H); /* H^2 */
450 ecp_nistz256_sqr_mont(Rsqr, R); /* R^2 */
451 ecp_nistz256_mul_mont(Hcub, Hsqr, H); /* H^3 */
452
453 ecp_nistz256_mul_mont(U2, in1_x, Hsqr); /* U1*H^2 */
454 ecp_nistz256_mul_by_2(Hsqr, U2); /* 2*U1*H^2 */
455
456 ecp_nistz256_sub(res_x, Rsqr, Hsqr);
457 ecp_nistz256_sub(res_x, res_x, Hcub);
458 ecp_nistz256_sub(H, U2, res_x);
459
460 ecp_nistz256_mul_mont(S2, in1_y, Hcub);
461 ecp_nistz256_mul_mont(H, H, R);
462 ecp_nistz256_sub(res_y, H, S2);
463
464 copy_conditional(res_x, in2_x, in1infty);
465 copy_conditional(res_x, in1_x, in2infty);
466
467 copy_conditional(res_y, in2_y, in1infty);
468 copy_conditional(res_y, in1_y, in2infty);
469
470 copy_conditional(res_z, ONE, in1infty);
471 copy_conditional(res_z, in1_z, in2infty);
472
473 memcpy(r->X, res_x, sizeof(res_x));
474 memcpy(r->Y, res_y, sizeof(res_y));
475 memcpy(r->Z, res_z, sizeof(res_z));
476 }
477 #endif
478
479 /* r = in^-1 mod p */
480 static void ecp_nistz256_mod_inverse(BN_ULONG r[P256_LIMBS],
481 const BN_ULONG in[P256_LIMBS])
482 {
483 /*
484 * The poly is ffffffff 00000001 00000000 00000000 00000000 ffffffff
485 * ffffffff ffffffff We use FLT and used poly-2 as exponent
486 */
487 BN_ULONG p2[P256_LIMBS];
488 BN_ULONG p4[P256_LIMBS];
489 BN_ULONG p8[P256_LIMBS];
490 BN_ULONG p16[P256_LIMBS];
491 BN_ULONG p32[P256_LIMBS];
492 BN_ULONG res[P256_LIMBS];
493 int i;
494
495 ecp_nistz256_sqr_mont(res, in);
496 ecp_nistz256_mul_mont(p2, res, in); /* 3*p */
497
498 ecp_nistz256_sqr_mont(res, p2);
499 ecp_nistz256_sqr_mont(res, res);
500 ecp_nistz256_mul_mont(p4, res, p2); /* f*p */
501
502 ecp_nistz256_sqr_mont(res, p4);
503 ecp_nistz256_sqr_mont(res, res);
504 ecp_nistz256_sqr_mont(res, res);
505 ecp_nistz256_sqr_mont(res, res);
506 ecp_nistz256_mul_mont(p8, res, p4); /* ff*p */
507
508 ecp_nistz256_sqr_mont(res, p8);
509 for (i = 0; i < 7; i++)
510 ecp_nistz256_sqr_mont(res, res);
511 ecp_nistz256_mul_mont(p16, res, p8); /* ffff*p */
512
513 ecp_nistz256_sqr_mont(res, p16);
514 for (i = 0; i < 15; i++)
515 ecp_nistz256_sqr_mont(res, res);
516 ecp_nistz256_mul_mont(p32, res, p16); /* ffffffff*p */
517
518 ecp_nistz256_sqr_mont(res, p32);
519 for (i = 0; i < 31; i++)
520 ecp_nistz256_sqr_mont(res, res);
521 ecp_nistz256_mul_mont(res, res, in);
522
523 for (i = 0; i < 32 * 4; i++)
524 ecp_nistz256_sqr_mont(res, res);
525 ecp_nistz256_mul_mont(res, res, p32);
526
527 for (i = 0; i < 32; i++)
528 ecp_nistz256_sqr_mont(res, res);
529 ecp_nistz256_mul_mont(res, res, p32);
530
531 for (i = 0; i < 16; i++)
532 ecp_nistz256_sqr_mont(res, res);
533 ecp_nistz256_mul_mont(res, res, p16);
534
535 for (i = 0; i < 8; i++)
536 ecp_nistz256_sqr_mont(res, res);
537 ecp_nistz256_mul_mont(res, res, p8);
538
539 ecp_nistz256_sqr_mont(res, res);
540 ecp_nistz256_sqr_mont(res, res);
541 ecp_nistz256_sqr_mont(res, res);
542 ecp_nistz256_sqr_mont(res, res);
543 ecp_nistz256_mul_mont(res, res, p4);
544
545 ecp_nistz256_sqr_mont(res, res);
546 ecp_nistz256_sqr_mont(res, res);
547 ecp_nistz256_mul_mont(res, res, p2);
548
549 ecp_nistz256_sqr_mont(res, res);
550 ecp_nistz256_sqr_mont(res, res);
551 ecp_nistz256_mul_mont(res, res, in);
552
553 memcpy(r, res, sizeof(res));
554 }
555
556 /*
557 * ecp_nistz256_bignum_to_field_elem copies the contents of |in| to |out| and
558 * returns one if it fits. Otherwise it returns zero.
559 */
560 static int ecp_nistz256_bignum_to_field_elem(BN_ULONG out[P256_LIMBS],
561 const BIGNUM *in)
562 {
563 if (in->top > P256_LIMBS)
564 return 0;
565
566 memset(out, 0, sizeof(BN_ULONG) * P256_LIMBS);
567 memcpy(out, in->d, sizeof(BN_ULONG) * in->top);
568 return 1;
569 }
570
571 /* r = sum(scalar[i]*point[i]) */
572 static int ecp_nistz256_windowed_mul(const EC_GROUP *group,
573 P256_POINT *r,
574 const BIGNUM **scalar,
575 const EC_POINT **point,
576 int num, BN_CTX *ctx)
577 {
578
579 int i, j, ret = 0;
580 unsigned int index;
581 unsigned char (*p_str)[33] = NULL;
582 const unsigned int window_size = 5;
583 const unsigned int mask = (1 << (window_size + 1)) - 1;
584 unsigned int wvalue;
585 BN_ULONG tmp[P256_LIMBS];
586 ALIGN32 P256_POINT h;
587 const BIGNUM **scalars = NULL;
588 P256_POINT (*table)[16] = NULL;
589 void *table_storage = NULL;
590
591 if ((table_storage =
592 OPENSSL_malloc(num * 16 * sizeof(P256_POINT) + 64)) == NULL
593 || (p_str =
594 OPENSSL_malloc(num * 33 * sizeof(unsigned char))) == NULL
595 || (scalars = OPENSSL_malloc(num * sizeof(BIGNUM *))) == NULL) {
596 ECerr(EC_F_ECP_NISTZ256_WINDOWED_MUL, ERR_R_MALLOC_FAILURE);
597 goto err;
598 } else {
599 table = (void *)ALIGNPTR(table_storage, 64);
600 }
601
602 for (i = 0; i < num; i++) {
603 P256_POINT *row = table[i];
604
605 /* This is an unusual input, we don't guarantee constant-timeness. */
606 if ((BN_num_bits(scalar[i]) > 256) || BN_is_negative(scalar[i])) {
607 BIGNUM *mod;
608
609 if ((mod = BN_CTX_get(ctx)) == NULL)
610 goto err;
611 if (!BN_nnmod(mod, scalar[i], &group->order, ctx)) {
612 ECerr(EC_F_ECP_NISTZ256_WINDOWED_MUL, ERR_R_BN_LIB);
613 goto err;
614 }
615 scalars[i] = mod;
616 } else
617 scalars[i] = scalar[i];
618
619 for (j = 0; j < scalars[i]->top * BN_BYTES; j += BN_BYTES) {
620 BN_ULONG d = scalars[i]->d[j / BN_BYTES];
621
622 p_str[i][j + 0] = d & 0xff;
623 p_str[i][j + 1] = (d >> 8) & 0xff;
624 p_str[i][j + 2] = (d >> 16) & 0xff;
625 p_str[i][j + 3] = (d >>= 24) & 0xff;
626 if (BN_BYTES == 8) {
627 d >>= 8;
628 p_str[i][j + 4] = d & 0xff;
629 p_str[i][j + 5] = (d >> 8) & 0xff;
630 p_str[i][j + 6] = (d >> 16) & 0xff;
631 p_str[i][j + 7] = (d >> 24) & 0xff;
632 }
633 }
634 for (; j < 33; j++)
635 p_str[i][j] = 0;
636
637 /* table[0] is implicitly (0,0,0) (the point at infinity),
638 * therefore it is not stored. All other values are actually
639 * stored with an offset of -1 in table.
640 */
641
642 if (!ecp_nistz256_bignum_to_field_elem(row[1 - 1].X, &point[i]->X)
643 || !ecp_nistz256_bignum_to_field_elem(row[1 - 1].Y, &point[i]->Y)
644 || !ecp_nistz256_bignum_to_field_elem(row[1 - 1].Z, &point[i]->Z)) {
645 ECerr(EC_F_ECP_NISTZ256_WINDOWED_MUL, EC_R_COORDINATES_OUT_OF_RANGE);
646 goto err;
647 }
648
649 ecp_nistz256_point_double(&row[ 2 - 1], &row[ 1 - 1]);
650 ecp_nistz256_point_add (&row[ 3 - 1], &row[ 2 - 1], &row[1 - 1]);
651 ecp_nistz256_point_double(&row[ 4 - 1], &row[ 2 - 1]);
652 ecp_nistz256_point_double(&row[ 6 - 1], &row[ 3 - 1]);
653 ecp_nistz256_point_double(&row[ 8 - 1], &row[ 4 - 1]);
654 ecp_nistz256_point_double(&row[12 - 1], &row[ 6 - 1]);
655 ecp_nistz256_point_add (&row[ 5 - 1], &row[ 4 - 1], &row[1 - 1]);
656 ecp_nistz256_point_add (&row[ 7 - 1], &row[ 6 - 1], &row[1 - 1]);
657 ecp_nistz256_point_add (&row[ 9 - 1], &row[ 8 - 1], &row[1 - 1]);
658 ecp_nistz256_point_add (&row[13 - 1], &row[12 - 1], &row[1 - 1]);
659 ecp_nistz256_point_double(&row[14 - 1], &row[ 7 - 1]);
660 ecp_nistz256_point_double(&row[10 - 1], &row[ 5 - 1]);
661 ecp_nistz256_point_add (&row[15 - 1], &row[14 - 1], &row[1 - 1]);
662 ecp_nistz256_point_add (&row[11 - 1], &row[10 - 1], &row[1 - 1]);
663 ecp_nistz256_point_add (&row[16 - 1], &row[15 - 1], &row[1 - 1]);
664 }
665
666 index = 255;
667
668 wvalue = p_str[0][(index - 1) / 8];
669 wvalue = (wvalue >> ((index - 1) % 8)) & mask;
670
671 ecp_nistz256_select_w5(r, table[0], _booth_recode_w5(wvalue) >> 1);
672
673 while (index >= 5) {
674 for (i = (index == 255 ? 1 : 0); i < num; i++) {
675 unsigned int off = (index - 1) / 8;
676
677 wvalue = p_str[i][off] | p_str[i][off + 1] << 8;
678 wvalue = (wvalue >> ((index - 1) % 8)) & mask;
679
680 wvalue = _booth_recode_w5(wvalue);
681
682 ecp_nistz256_select_w5(&h, table[i], wvalue >> 1);
683
684 ecp_nistz256_neg(tmp, h.Y);
685 copy_conditional(h.Y, tmp, (wvalue & 1));
686
687 ecp_nistz256_point_add(r, r, &h);
688 }
689
690 index -= window_size;
691
692 ecp_nistz256_point_double(r, r);
693 ecp_nistz256_point_double(r, r);
694 ecp_nistz256_point_double(r, r);
695 ecp_nistz256_point_double(r, r);
696 ecp_nistz256_point_double(r, r);
697 }
698
699 /* Final window */
700 for (i = 0; i < num; i++) {
701 wvalue = p_str[i][0];
702 wvalue = (wvalue << 1) & mask;
703
704 wvalue = _booth_recode_w5(wvalue);
705
706 ecp_nistz256_select_w5(&h, table[i], wvalue >> 1);
707
708 ecp_nistz256_neg(tmp, h.Y);
709 copy_conditional(h.Y, tmp, wvalue & 1);
710
711 ecp_nistz256_point_add(r, r, &h);
712 }
713
714 ret = 1;
715 err:
716 if (table_storage)
717 OPENSSL_free(table_storage);
718 if (p_str)
719 OPENSSL_free(p_str);
720 if (scalars)
721 OPENSSL_free(scalars);
722 return ret;
723 }
724
725 /* Coordinates of G, for which we have precomputed tables */
726 const static BN_ULONG def_xG[P256_LIMBS] = {
727 TOBN(0x79e730d4, 0x18a9143c), TOBN(0x75ba95fc, 0x5fedb601),
728 TOBN(0x79fb732b, 0x77622510), TOBN(0x18905f76, 0xa53755c6)
729 };
730
731 const static BN_ULONG def_yG[P256_LIMBS] = {
732 TOBN(0xddf25357, 0xce95560a), TOBN(0x8b4ab8e4, 0xba19e45c),
733 TOBN(0xd2e88688, 0xdd21f325), TOBN(0x8571ff18, 0x25885d85)
734 };
735
736 /*
737 * ecp_nistz256_is_affine_G returns one if |generator| is the standard, P-256
738 * generator.
739 */
740 static int ecp_nistz256_is_affine_G(const EC_POINT *generator)
741 {
742 return (generator->X.top == P256_LIMBS) &&
743 (generator->Y.top == P256_LIMBS) &&
744 (generator->Z.top == (P256_LIMBS - P256_LIMBS / 8)) &&
745 is_equal(generator->X.d, def_xG) &&
746 is_equal(generator->Y.d, def_yG) && is_one(generator->Z.d);
747 }
748
749 static int ecp_nistz256_mult_precompute(EC_GROUP *group, BN_CTX *ctx)
750 {
751 /*
752 * We precompute a table for a Booth encoded exponent (wNAF) based
753 * computation. Each table holds 64 values for safe access, with an
754 * implicit value of infinity at index zero. We use window of size 7, and
755 * therefore require ceil(256/7) = 37 tables.
756 */
757 BIGNUM *order;
758 EC_POINT *P = NULL, *T = NULL;
759 const EC_POINT *generator;
760 EC_PRE_COMP *pre_comp;
761 BN_CTX *new_ctx = NULL;
762 int i, j, k, ret = 0;
763 size_t w;
764
765 PRECOMP256_ROW *preComputedTable = NULL;
766 unsigned char *precomp_storage = NULL;
767
768 /* if there is an old EC_PRE_COMP object, throw it away */
769 EC_EX_DATA_free_data(&group->extra_data, ecp_nistz256_pre_comp_dup,
770 ecp_nistz256_pre_comp_free,
771 ecp_nistz256_pre_comp_clear_free);
772
773 generator = EC_GROUP_get0_generator(group);
774 if (generator == NULL) {
775 ECerr(EC_F_ECP_NISTZ256_MULT_PRECOMPUTE, EC_R_UNDEFINED_GENERATOR);
776 return 0;
777 }
778
779 if (ecp_nistz256_is_affine_G(generator)) {
780 /*
781 * No need to calculate tables for the standard generator because we
782 * have them statically.
783 */
784 return 1;
785 }
786
787 if ((pre_comp = ecp_nistz256_pre_comp_new(group)) == NULL)
788 return 0;
789
790 if (ctx == NULL) {
791 ctx = new_ctx = BN_CTX_new();
792 if (ctx == NULL)
793 goto err;
794 }
795
796 BN_CTX_start(ctx);
797 order = BN_CTX_get(ctx);
798
799 if (order == NULL)
800 goto err;
801
802 if (!EC_GROUP_get_order(group, order, ctx))
803 goto err;
804
805 if (BN_is_zero(order)) {
806 ECerr(EC_F_ECP_NISTZ256_MULT_PRECOMPUTE, EC_R_UNKNOWN_ORDER);
807 goto err;
808 }
809
810 w = 7;
811
812 if ((precomp_storage =
813 OPENSSL_malloc(37 * 64 * sizeof(P256_POINT_AFFINE) + 64)) == NULL) {
814 ECerr(EC_F_ECP_NISTZ256_MULT_PRECOMPUTE, ERR_R_MALLOC_FAILURE);
815 goto err;
816 } else {
817 preComputedTable = (void *)ALIGNPTR(precomp_storage, 64);
818 }
819
820 P = EC_POINT_new(group);
821 T = EC_POINT_new(group);
822 if (P == NULL || T == NULL)
823 goto err;
824
825 /*
826 * The zero entry is implicitly infinity, and we skip it, storing other
827 * values with -1 offset.
828 */
829 if (!EC_POINT_copy(T, generator))
830 goto err;
831
832 for (k = 0; k < 64; k++) {
833 if (!EC_POINT_copy(P, T))
834 goto err;
835 for (j = 0; j < 37; j++) {
836 /*
837 * It would be faster to use EC_POINTs_make_affine and
838 * make multiple points affine at the same time.
839 */
840 if (!EC_POINT_make_affine(group, P, ctx))
841 goto err;
842 if (!ecp_nistz256_bignum_to_field_elem(preComputedTable[j][k].X,
843 &P->X) ||
844 !ecp_nistz256_bignum_to_field_elem(preComputedTable[j][k].Y,
845 &P->Y)) {
846 ECerr(EC_F_ECP_NISTZ256_MULT_PRECOMPUTE,
847 EC_R_COORDINATES_OUT_OF_RANGE);
848 goto err;
849 }
850 for (i = 0; i < 7; i++) {
851 if (!EC_POINT_dbl(group, P, P, ctx))
852 goto err;
853 }
854 }
855 if (!EC_POINT_add(group, T, T, generator, ctx))
856 goto err;
857 }
858
859 pre_comp->group = group;
860 pre_comp->w = w;
861 pre_comp->precomp = preComputedTable;
862 pre_comp->precomp_storage = precomp_storage;
863
864 precomp_storage = NULL;
865
866 if (!EC_EX_DATA_set_data(&group->extra_data, pre_comp,
867 ecp_nistz256_pre_comp_dup,
868 ecp_nistz256_pre_comp_free,
869 ecp_nistz256_pre_comp_clear_free)) {
870 goto err;
871 }
872
873 pre_comp = NULL;
874
875 ret = 1;
876
877 err:
878 if (ctx != NULL)
879 BN_CTX_end(ctx);
880 BN_CTX_free(new_ctx);
881
882 if (pre_comp)
883 ecp_nistz256_pre_comp_free(pre_comp);
884 if (precomp_storage)
885 OPENSSL_free(precomp_storage);
886 if (P)
887 EC_POINT_free(P);
888 if (T)
889 EC_POINT_free(T);
890 return ret;
891 }
892
893 /*
894 * Note that by default ECP_NISTZ256_AVX2 is undefined. While it's great
895 * code processing 4 points in parallel, corresponding serial operation
896 * is several times slower, because it uses 29x29=58-bit multiplication
897 * as opposite to 64x64=128-bit in integer-only scalar case. As result
898 * it doesn't provide *significant* performance improvement. Note that
899 * just defining ECP_NISTZ256_AVX2 is not sufficient to make it work,
900 * you'd need to compile even asm/ecp_nistz256-avx.pl module.
901 */
902 #if defined(ECP_NISTZ256_AVX2)
903 # if !(defined(__x86_64) || defined(__x86_64__)) || \
904 defined(_M_AMD64) || defined(_MX64)) || \
905 !(defined(__GNUC__) || defined(_MSC_VER)) /* this is for ALIGN32 */
906 # undef ECP_NISTZ256_AVX2
907 # else
908 /* Constant time access, loading four values, from four consecutive tables */
909 void ecp_nistz256_avx2_select_w7(P256_POINT_AFFINE * val,
910 const P256_POINT_AFFINE * in_t, int index);
911 void ecp_nistz256_avx2_multi_select_w7(void *result, const void *in, int index0,
912 int index1, int index2, int index3);
913 void ecp_nistz256_avx2_transpose_convert(void *RESULTx4, const void *in);
914 void ecp_nistz256_avx2_convert_transpose_back(void *result, const void *Ax4);
915 void ecp_nistz256_avx2_point_add_affine_x4(void *RESULTx4, const void *Ax4,
916 const void *Bx4);
917 void ecp_nistz256_avx2_point_add_affines_x4(void *RESULTx4, const void *Ax4,
918 const void *Bx4);
919 void ecp_nistz256_avx2_to_mont(void *RESULTx4, const void *Ax4);
920 void ecp_nistz256_avx2_from_mont(void *RESULTx4, const void *Ax4);
921 void ecp_nistz256_avx2_set1(void *RESULTx4);
922 int ecp_nistz_avx2_eligible(void);
923
924 static void booth_recode_w7(unsigned char *sign,
925 unsigned char *digit, unsigned char in)
926 {
927 unsigned char s, d;
928
929 s = ~((in >> 7) - 1);
930 d = (1 << 8) - in - 1;
931 d = (d & s) | (in & ~s);
932 d = (d >> 1) + (d & 1);
933
934 *sign = s & 1;
935 *digit = d;
936 }
937
938 /*
939 * ecp_nistz256_avx2_mul_g performs multiplication by G, using only the
940 * precomputed table. It does 4 affine point additions in parallel,
941 * significantly speeding up point multiplication for a fixed value.
942 */
943 static void ecp_nistz256_avx2_mul_g(P256_POINT *r,
944 unsigned char p_str[33],
945 const P256_POINT_AFFINE(*preComputedTable)[64])
946 {
947 const unsigned int window_size = 7;
948 const unsigned int mask = (1 << (window_size + 1)) - 1;
949 unsigned int wvalue;
950 /* Using 4 windows at a time */
951 unsigned char sign0, digit0;
952 unsigned char sign1, digit1;
953 unsigned char sign2, digit2;
954 unsigned char sign3, digit3;
955 unsigned int index = 0;
956 BN_ULONG tmp[P256_LIMBS];
957 int i;
958
959 ALIGN32 BN_ULONG aX4[4 * 9 * 3] = { 0 };
960 ALIGN32 BN_ULONG bX4[4 * 9 * 2] = { 0 };
961 ALIGN32 P256_POINT_AFFINE point_arr[P256_LIMBS];
962 ALIGN32 P256_POINT res_point_arr[P256_LIMBS];
963
964 /* Initial four windows */
965 wvalue = *((u16 *) & p_str[0]);
966 wvalue = (wvalue << 1) & mask;
967 index += window_size;
968 booth_recode_w7(&sign0, &digit0, wvalue);
969 wvalue = *((u16 *) & p_str[(index - 1) / 8]);
970 wvalue = (wvalue >> ((index - 1) % 8)) & mask;
971 index += window_size;
972 booth_recode_w7(&sign1, &digit1, wvalue);
973 wvalue = *((u16 *) & p_str[(index - 1) / 8]);
974 wvalue = (wvalue >> ((index - 1) % 8)) & mask;
975 index += window_size;
976 booth_recode_w7(&sign2, &digit2, wvalue);
977 wvalue = *((u16 *) & p_str[(index - 1) / 8]);
978 wvalue = (wvalue >> ((index - 1) % 8)) & mask;
979 index += window_size;
980 booth_recode_w7(&sign3, &digit3, wvalue);
981
982 ecp_nistz256_avx2_multi_select_w7(point_arr, preComputedTable[0],
983 digit0, digit1, digit2, digit3);
984
985 ecp_nistz256_neg(tmp, point_arr[0].Y);
986 copy_conditional(point_arr[0].Y, tmp, sign0);
987 ecp_nistz256_neg(tmp, point_arr[1].Y);
988 copy_conditional(point_arr[1].Y, tmp, sign1);
989 ecp_nistz256_neg(tmp, point_arr[2].Y);
990 copy_conditional(point_arr[2].Y, tmp, sign2);
991 ecp_nistz256_neg(tmp, point_arr[3].Y);
992 copy_conditional(point_arr[3].Y, tmp, sign3);
993
994 ecp_nistz256_avx2_transpose_convert(aX4, point_arr);
995 ecp_nistz256_avx2_to_mont(aX4, aX4);
996 ecp_nistz256_avx2_to_mont(&aX4[4 * 9], &aX4[4 * 9]);
997 ecp_nistz256_avx2_set1(&aX4[4 * 9 * 2]);
998
999 wvalue = *((u16 *) & p_str[(index - 1) / 8]);
1000 wvalue = (wvalue >> ((index - 1) % 8)) & mask;
1001 index += window_size;
1002 booth_recode_w7(&sign0, &digit0, wvalue);
1003 wvalue = *((u16 *) & p_str[(index - 1) / 8]);
1004 wvalue = (wvalue >> ((index - 1) % 8)) & mask;
1005 index += window_size;
1006 booth_recode_w7(&sign1, &digit1, wvalue);
1007 wvalue = *((u16 *) & p_str[(index - 1) / 8]);
1008 wvalue = (wvalue >> ((index - 1) % 8)) & mask;
1009 index += window_size;
1010 booth_recode_w7(&sign2, &digit2, wvalue);
1011 wvalue = *((u16 *) & p_str[(index - 1) / 8]);
1012 wvalue = (wvalue >> ((index - 1) % 8)) & mask;
1013 index += window_size;
1014 booth_recode_w7(&sign3, &digit3, wvalue);
1015
1016 ecp_nistz256_avx2_multi_select_w7(point_arr, preComputedTable[4 * 1],
1017 digit0, digit1, digit2, digit3);
1018
1019 ecp_nistz256_neg(tmp, point_arr[0].Y);
1020 copy_conditional(point_arr[0].Y, tmp, sign0);
1021 ecp_nistz256_neg(tmp, point_arr[1].Y);
1022 copy_conditional(point_arr[1].Y, tmp, sign1);
1023 ecp_nistz256_neg(tmp, point_arr[2].Y);
1024 copy_conditional(point_arr[2].Y, tmp, sign2);
1025 ecp_nistz256_neg(tmp, point_arr[3].Y);
1026 copy_conditional(point_arr[3].Y, tmp, sign3);
1027
1028 ecp_nistz256_avx2_transpose_convert(bX4, point_arr);
1029 ecp_nistz256_avx2_to_mont(bX4, bX4);
1030 ecp_nistz256_avx2_to_mont(&bX4[4 * 9], &bX4[4 * 9]);
1031 /* Optimized when both inputs are affine */
1032 ecp_nistz256_avx2_point_add_affines_x4(aX4, aX4, bX4);
1033
1034 for (i = 2; i < 9; i++) {
1035 wvalue = *((u16 *) & p_str[(index - 1) / 8]);
1036 wvalue = (wvalue >> ((index - 1) % 8)) & mask;
1037 index += window_size;
1038 booth_recode_w7(&sign0, &digit0, wvalue);
1039 wvalue = *((u16 *) & p_str[(index - 1) / 8]);
1040 wvalue = (wvalue >> ((index - 1) % 8)) & mask;
1041 index += window_size;
1042 booth_recode_w7(&sign1, &digit1, wvalue);
1043 wvalue = *((u16 *) & p_str[(index - 1) / 8]);
1044 wvalue = (wvalue >> ((index - 1) % 8)) & mask;
1045 index += window_size;
1046 booth_recode_w7(&sign2, &digit2, wvalue);
1047 wvalue = *((u16 *) & p_str[(index - 1) / 8]);
1048 wvalue = (wvalue >> ((index - 1) % 8)) & mask;
1049 index += window_size;
1050 booth_recode_w7(&sign3, &digit3, wvalue);
1051
1052 ecp_nistz256_avx2_multi_select_w7(point_arr,
1053 preComputedTable[4 * i],
1054 digit0, digit1, digit2, digit3);
1055
1056 ecp_nistz256_neg(tmp, point_arr[0].Y);
1057 copy_conditional(point_arr[0].Y, tmp, sign0);
1058 ecp_nistz256_neg(tmp, point_arr[1].Y);
1059 copy_conditional(point_arr[1].Y, tmp, sign1);
1060 ecp_nistz256_neg(tmp, point_arr[2].Y);
1061 copy_conditional(point_arr[2].Y, tmp, sign2);
1062 ecp_nistz256_neg(tmp, point_arr[3].Y);
1063 copy_conditional(point_arr[3].Y, tmp, sign3);
1064
1065 ecp_nistz256_avx2_transpose_convert(bX4, point_arr);
1066 ecp_nistz256_avx2_to_mont(bX4, bX4);
1067 ecp_nistz256_avx2_to_mont(&bX4[4 * 9], &bX4[4 * 9]);
1068
1069 ecp_nistz256_avx2_point_add_affine_x4(aX4, aX4, bX4);
1070 }
1071
1072 ecp_nistz256_avx2_from_mont(&aX4[4 * 9 * 0], &aX4[4 * 9 * 0]);
1073 ecp_nistz256_avx2_from_mont(&aX4[4 * 9 * 1], &aX4[4 * 9 * 1]);
1074 ecp_nistz256_avx2_from_mont(&aX4[4 * 9 * 2], &aX4[4 * 9 * 2]);
1075
1076 ecp_nistz256_avx2_convert_transpose_back(res_point_arr, aX4);
1077 /* Last window is performed serially */
1078 wvalue = *((u16 *) & p_str[(index - 1) / 8]);
1079 wvalue = (wvalue >> ((index - 1) % 8)) & mask;
1080 booth_recode_w7(&sign0, &digit0, wvalue);
1081 ecp_nistz256_avx2_select_w7((P256_POINT_AFFINE *) r,
1082 preComputedTable[36], digit0);
1083 ecp_nistz256_neg(tmp, r->Y);
1084 copy_conditional(r->Y, tmp, sign0);
1085 memcpy(r->Z, ONE, sizeof(ONE));
1086 /* Sum the four windows */
1087 ecp_nistz256_point_add(r, r, &res_point_arr[0]);
1088 ecp_nistz256_point_add(r, r, &res_point_arr[1]);
1089 ecp_nistz256_point_add(r, r, &res_point_arr[2]);
1090 ecp_nistz256_point_add(r, r, &res_point_arr[3]);
1091 }
1092 # endif
1093 #endif
1094
1095 static int ecp_nistz256_set_from_affine(EC_POINT *out, const EC_GROUP *group,
1096 const P256_POINT_AFFINE *in,
1097 BN_CTX *ctx)
1098 {
1099 BIGNUM x, y;
1100 BN_ULONG d_x[P256_LIMBS], d_y[P256_LIMBS];
1101 int ret = 0;
1102
1103 memcpy(d_x, in->X, sizeof(d_x));
1104 x.d = d_x;
1105 x.dmax = x.top = P256_LIMBS;
1106 x.neg = 0;
1107 x.flags = BN_FLG_STATIC_DATA;
1108
1109 memcpy(d_y, in->Y, sizeof(d_y));
1110 y.d = d_y;
1111 y.dmax = y.top = P256_LIMBS;
1112 y.neg = 0;
1113 y.flags = BN_FLG_STATIC_DATA;
1114
1115 ret = EC_POINT_set_affine_coordinates_GFp(group, out, &x, &y, ctx);
1116
1117 return ret;
1118 }
1119
1120 /* r = scalar*G + sum(scalars[i]*points[i]) */
1121 static int ecp_nistz256_points_mul(const EC_GROUP *group,
1122 EC_POINT *r,
1123 const BIGNUM *scalar,
1124 size_t num,
1125 const EC_POINT *points[],
1126 const BIGNUM *scalars[], BN_CTX *ctx)
1127 {
1128 int i = 0, ret = 0, no_precomp_for_generator = 0, p_is_infinity = 0;
1129 size_t j;
1130 unsigned char p_str[33] = { 0 };
1131 const PRECOMP256_ROW *preComputedTable = NULL;
1132 const EC_PRE_COMP *pre_comp = NULL;
1133 const EC_POINT *generator = NULL;
1134 unsigned int index = 0;
1135 BN_CTX *new_ctx = NULL;
1136 const BIGNUM **new_scalars = NULL;
1137 const EC_POINT **new_points = NULL;
1138 const unsigned int window_size = 7;
1139 const unsigned int mask = (1 << (window_size + 1)) - 1;
1140 unsigned int wvalue;
1141 ALIGN32 union {
1142 P256_POINT p;
1143 P256_POINT_AFFINE a;
1144 } t, p;
1145 BIGNUM *tmp_scalar;
1146
1147 if (group->meth != r->meth) {
1148 ECerr(EC_F_ECP_NISTZ256_POINTS_MUL, EC_R_INCOMPATIBLE_OBJECTS);
1149 return 0;
1150 }
1151
1152 if ((scalar == NULL) && (num == 0))
1153 return EC_POINT_set_to_infinity(group, r);
1154
1155 for (j = 0; j < num; j++) {
1156 if (group->meth != points[j]->meth) {
1157 ECerr(EC_F_ECP_NISTZ256_POINTS_MUL, EC_R_INCOMPATIBLE_OBJECTS);
1158 return 0;
1159 }
1160 }
1161
1162 if (ctx == NULL) {
1163 ctx = new_ctx = BN_CTX_new();
1164 if (ctx == NULL)
1165 goto err;
1166 }
1167
1168 BN_CTX_start(ctx);
1169
1170 if (scalar) {
1171 generator = EC_GROUP_get0_generator(group);
1172 if (generator == NULL) {
1173 ECerr(EC_F_ECP_NISTZ256_POINTS_MUL, EC_R_UNDEFINED_GENERATOR);
1174 goto err;
1175 }
1176
1177 /* look if we can use precomputed multiples of generator */
1178 pre_comp =
1179 EC_EX_DATA_get_data(group->extra_data, ecp_nistz256_pre_comp_dup,
1180 ecp_nistz256_pre_comp_free,
1181 ecp_nistz256_pre_comp_clear_free);
1182
1183 if (pre_comp) {
1184 /*
1185 * If there is a precomputed table for the generator, check that
1186 * it was generated with the same generator.
1187 */
1188 EC_POINT *pre_comp_generator = EC_POINT_new(group);
1189 if (pre_comp_generator == NULL)
1190 goto err;
1191
1192 if (!ecp_nistz256_set_from_affine
1193 (pre_comp_generator, group, pre_comp->precomp[0], ctx)) {
1194 EC_POINT_free(pre_comp_generator);
1195 goto err;
1196 }
1197
1198 if (0 == EC_POINT_cmp(group, generator, pre_comp_generator, ctx))
1199 preComputedTable = (const PRECOMP256_ROW *)pre_comp->precomp;
1200
1201 EC_POINT_free(pre_comp_generator);
1202 }
1203
1204 if (preComputedTable == NULL && ecp_nistz256_is_affine_G(generator)) {
1205 /*
1206 * If there is no precomputed data, but the generator
1207 * is the default, a hardcoded table of precomputed
1208 * data is used. This is because applications, such as
1209 * Apache, do not use EC_KEY_precompute_mult.
1210 */
1211 preComputedTable = (const PRECOMP256_ROW *)ecp_nistz256_precomputed;
1212 }
1213
1214 if (preComputedTable) {
1215 if ((BN_num_bits(scalar) > 256)
1216 || BN_is_negative(scalar)) {
1217 if ((tmp_scalar = BN_CTX_get(ctx)) == NULL)
1218 goto err;
1219
1220 if (!BN_nnmod(tmp_scalar, scalar, &group->order, ctx)) {
1221 ECerr(EC_F_ECP_NISTZ256_POINTS_MUL, ERR_R_BN_LIB);
1222 goto err;
1223 }
1224 scalar = tmp_scalar;
1225 }
1226
1227 for (i = 0; i < scalar->top * BN_BYTES; i += BN_BYTES) {
1228 BN_ULONG d = scalar->d[i / BN_BYTES];
1229
1230 p_str[i + 0] = d & 0xff;
1231 p_str[i + 1] = (d >> 8) & 0xff;
1232 p_str[i + 2] = (d >> 16) & 0xff;
1233 p_str[i + 3] = (d >>= 24) & 0xff;
1234 if (BN_BYTES == 8) {
1235 d >>= 8;
1236 p_str[i + 4] = d & 0xff;
1237 p_str[i + 5] = (d >> 8) & 0xff;
1238 p_str[i + 6] = (d >> 16) & 0xff;
1239 p_str[i + 7] = (d >> 24) & 0xff;
1240 }
1241 }
1242
1243 for (; i < 33; i++)
1244 p_str[i] = 0;
1245
1246 #if defined(ECP_NISTZ256_AVX2)
1247 if (ecp_nistz_avx2_eligible()) {
1248 ecp_nistz256_avx2_mul_g(&p.p, p_str, preComputedTable);
1249 } else
1250 #endif
1251 {
1252 /* First window */
1253 wvalue = (p_str[0] << 1) & mask;
1254 index += window_size;
1255
1256 wvalue = _booth_recode_w7(wvalue);
1257
1258 ecp_nistz256_select_w7(&p.a, preComputedTable[0], wvalue >> 1);
1259
1260 ecp_nistz256_neg(p.p.Z, p.p.Y);
1261 copy_conditional(p.p.Y, p.p.Z, wvalue & 1);
1262
1263 memcpy(p.p.Z, ONE, sizeof(ONE));
1264
1265 for (i = 1; i < 37; i++) {
1266 unsigned int off = (index - 1) / 8;
1267 wvalue = p_str[off] | p_str[off + 1] << 8;
1268 wvalue = (wvalue >> ((index - 1) % 8)) & mask;
1269 index += window_size;
1270
1271 wvalue = _booth_recode_w7(wvalue);
1272
1273 ecp_nistz256_select_w7(&t.a,
1274 preComputedTable[i], wvalue >> 1);
1275
1276 ecp_nistz256_neg(t.p.Z, t.a.Y);
1277 copy_conditional(t.a.Y, t.p.Z, wvalue & 1);
1278
1279 ecp_nistz256_point_add_affine(&p.p, &p.p, &t.a);
1280 }
1281 }
1282 } else {
1283 p_is_infinity = 1;
1284 no_precomp_for_generator = 1;
1285 }
1286 } else
1287 p_is_infinity = 1;
1288
1289 if (no_precomp_for_generator) {
1290 /*
1291 * Without a precomputed table for the generator, it has to be
1292 * handled like a normal point.
1293 */
1294 new_scalars = OPENSSL_malloc((num + 1) * sizeof(BIGNUM *));
1295 if (!new_scalars) {
1296 ECerr(EC_F_ECP_NISTZ256_POINTS_MUL, ERR_R_MALLOC_FAILURE);
1297 goto err;
1298 }
1299
1300 new_points = OPENSSL_malloc((num + 1) * sizeof(EC_POINT *));
1301 if (!new_points) {
1302 ECerr(EC_F_ECP_NISTZ256_POINTS_MUL, ERR_R_MALLOC_FAILURE);
1303 goto err;
1304 }
1305
1306 memcpy(new_scalars, scalars, num * sizeof(BIGNUM *));
1307 new_scalars[num] = scalar;
1308 memcpy(new_points, points, num * sizeof(EC_POINT *));
1309 new_points[num] = generator;
1310
1311 scalars = new_scalars;
1312 points = new_points;
1313 num++;
1314 }
1315
1316 if (num) {
1317 P256_POINT *out = &t.p;
1318 if (p_is_infinity)
1319 out = &p.p;
1320
1321 if (!ecp_nistz256_windowed_mul(group, out, scalars, points, num, ctx))
1322 goto err;
1323
1324 if (!p_is_infinity)
1325 ecp_nistz256_point_add(&p.p, &p.p, out);
1326 }
1327
1328 /* Not constant-time, but we're only operating on the public output. */
1329 if (!ecp_nistz256_set_words(&r->X, p.p.X) ||
1330 !ecp_nistz256_set_words(&r->Y, p.p.Y) ||
1331 !ecp_nistz256_set_words(&r->Z, p.p.Z)) {
1332 goto err;
1333 }
1334 r->Z_is_one = is_one(p.p.Z) & 1;
1335
1336 ret = 1;
1337
1338 err:
1339 if (ctx)
1340 BN_CTX_end(ctx);
1341 BN_CTX_free(new_ctx);
1342 if (new_points)
1343 OPENSSL_free(new_points);
1344 if (new_scalars)
1345 OPENSSL_free(new_scalars);
1346 return ret;
1347 }
1348
1349 static int ecp_nistz256_get_affine(const EC_GROUP *group,
1350 const EC_POINT *point,
1351 BIGNUM *x, BIGNUM *y, BN_CTX *ctx)
1352 {
1353 BN_ULONG z_inv2[P256_LIMBS];
1354 BN_ULONG z_inv3[P256_LIMBS];
1355 BN_ULONG x_aff[P256_LIMBS];
1356 BN_ULONG y_aff[P256_LIMBS];
1357 BN_ULONG point_x[P256_LIMBS], point_y[P256_LIMBS], point_z[P256_LIMBS];
1358 BN_ULONG x_ret[P256_LIMBS], y_ret[P256_LIMBS];
1359
1360 if (EC_POINT_is_at_infinity(group, point)) {
1361 ECerr(EC_F_ECP_NISTZ256_GET_AFFINE, EC_R_POINT_AT_INFINITY);
1362 return 0;
1363 }
1364
1365 if (!ecp_nistz256_bignum_to_field_elem(point_x, &point->X) ||
1366 !ecp_nistz256_bignum_to_field_elem(point_y, &point->Y) ||
1367 !ecp_nistz256_bignum_to_field_elem(point_z, &point->Z)) {
1368 ECerr(EC_F_ECP_NISTZ256_GET_AFFINE, EC_R_COORDINATES_OUT_OF_RANGE);
1369 return 0;
1370 }
1371
1372 ecp_nistz256_mod_inverse(z_inv3, point_z);
1373 ecp_nistz256_sqr_mont(z_inv2, z_inv3);
1374 ecp_nistz256_mul_mont(x_aff, z_inv2, point_x);
1375
1376 if (x != NULL) {
1377 ecp_nistz256_from_mont(x_ret, x_aff);
1378 if (!ecp_nistz256_set_words(x, x_ret))
1379 return 0;
1380 }
1381
1382 if (y != NULL) {
1383 ecp_nistz256_mul_mont(z_inv3, z_inv3, z_inv2);
1384 ecp_nistz256_mul_mont(y_aff, z_inv3, point_y);
1385 ecp_nistz256_from_mont(y_ret, y_aff);
1386 if (!ecp_nistz256_set_words(y, y_ret))
1387 return 0;
1388 }
1389
1390 return 1;
1391 }
1392
1393 static EC_PRE_COMP *ecp_nistz256_pre_comp_new(const EC_GROUP *group)
1394 {
1395 EC_PRE_COMP *ret = NULL;
1396
1397 if (!group)
1398 return NULL;
1399
1400 ret = (EC_PRE_COMP *)OPENSSL_malloc(sizeof(EC_PRE_COMP));
1401
1402 if (!ret) {
1403 ECerr(EC_F_ECP_NISTZ256_PRE_COMP_NEW, ERR_R_MALLOC_FAILURE);
1404 return ret;
1405 }
1406
1407 ret->group = group;
1408 ret->w = 6; /* default */
1409 ret->precomp = NULL;
1410 ret->precomp_storage = NULL;
1411 ret->references = 1;
1412 return ret;
1413 }
1414
1415 static void *ecp_nistz256_pre_comp_dup(void *src_)
1416 {
1417 EC_PRE_COMP *src = src_;
1418
1419 /* no need to actually copy, these objects never change! */
1420 CRYPTO_add(&src->references, 1, CRYPTO_LOCK_EC_PRE_COMP);
1421
1422 return src_;
1423 }
1424
1425 static void ecp_nistz256_pre_comp_free(void *pre_)
1426 {
1427 int i;
1428 EC_PRE_COMP *pre = pre_;
1429
1430 if (!pre)
1431 return;
1432
1433 i = CRYPTO_add(&pre->references, -1, CRYPTO_LOCK_EC_PRE_COMP);
1434 if (i > 0)
1435 return;
1436
1437 if (pre->precomp_storage)
1438 OPENSSL_free(pre->precomp_storage);
1439
1440 OPENSSL_free(pre);
1441 }
1442
1443 static void ecp_nistz256_pre_comp_clear_free(void *pre_)
1444 {
1445 int i;
1446 EC_PRE_COMP *pre = pre_;
1447
1448 if (!pre)
1449 return;
1450
1451 i = CRYPTO_add(&pre->references, -1, CRYPTO_LOCK_EC_PRE_COMP);
1452 if (i > 0)
1453 return;
1454
1455 if (pre->precomp_storage) {
1456 OPENSSL_cleanse(pre->precomp,
1457 32 * sizeof(unsigned char) * (1 << pre->w) * 2 * 37);
1458 OPENSSL_free(pre->precomp_storage);
1459 }
1460 OPENSSL_cleanse(pre, sizeof *pre);
1461 OPENSSL_free(pre);
1462 }
1463
1464 static int ecp_nistz256_window_have_precompute_mult(const EC_GROUP *group)
1465 {
1466 /* There is a hard-coded table for the default generator. */
1467 const EC_POINT *generator = EC_GROUP_get0_generator(group);
1468 if (generator != NULL && ecp_nistz256_is_affine_G(generator)) {
1469 /* There is a hard-coded table for the default generator. */
1470 return 1;
1471 }
1472
1473 return EC_EX_DATA_get_data(group->extra_data, ecp_nistz256_pre_comp_dup,
1474 ecp_nistz256_pre_comp_free,
1475 ecp_nistz256_pre_comp_clear_free) != NULL;
1476 }
1477
1478 const EC_METHOD *EC_GFp_nistz256_method(void)
1479 {
1480 static const EC_METHOD ret = {
1481 EC_FLAGS_DEFAULT_OCT,
1482 NID_X9_62_prime_field,
1483 ec_GFp_mont_group_init,
1484 ec_GFp_mont_group_finish,
1485 ec_GFp_mont_group_clear_finish,
1486 ec_GFp_mont_group_copy,
1487 ec_GFp_mont_group_set_curve,
1488 ec_GFp_simple_group_get_curve,
1489 ec_GFp_simple_group_get_degree,
1490 ec_GFp_simple_group_check_discriminant,
1491 ec_GFp_simple_point_init,
1492 ec_GFp_simple_point_finish,
1493 ec_GFp_simple_point_clear_finish,
1494 ec_GFp_simple_point_copy,
1495 ec_GFp_simple_point_set_to_infinity,
1496 ec_GFp_simple_set_Jprojective_coordinates_GFp,
1497 ec_GFp_simple_get_Jprojective_coordinates_GFp,
1498 ec_GFp_simple_point_set_affine_coordinates,
1499 ecp_nistz256_get_affine,
1500 0, 0, 0,
1501 ec_GFp_simple_add,
1502 ec_GFp_simple_dbl,
1503 ec_GFp_simple_invert,
1504 ec_GFp_simple_is_at_infinity,
1505 ec_GFp_simple_is_on_curve,
1506 ec_GFp_simple_cmp,
1507 ec_GFp_simple_make_affine,
1508 ec_GFp_simple_points_make_affine,
1509 ecp_nistz256_points_mul, /* mul */
1510 ecp_nistz256_mult_precompute, /* precompute_mult */
1511 ecp_nistz256_window_have_precompute_mult, /* have_precompute_mult */
1512 ec_GFp_mont_field_mul,
1513 ec_GFp_mont_field_sqr,
1514 0, /* field_div */
1515 ec_GFp_mont_field_encode,
1516 ec_GFp_mont_field_decode,
1517 ec_GFp_mont_field_set_to_one
1518 };
1519
1520 return &ret;
1521 }
Tomato firmware and modifications.