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26
27#include <crypto/ecc_curve.h>
28#include <linux/module.h>
29#include <linux/random.h>
30#include <linux/slab.h>
31#include <linux/swab.h>
32#include <linux/fips.h>
33#include <crypto/ecdh.h>
34#include <crypto/rng.h>
35#include <asm/unaligned.h>
36#include <linux/ratelimit.h>
37
38#include "ecc.h"
39#include "ecc_curve_defs.h"
40
41typedef struct {
42 u64 m_low;
43 u64 m_high;
44} uint128_t;
45
46
47const struct ecc_curve *ecc_get_curve25519(void)
48{
49 return &ecc_25519;
50}
51EXPORT_SYMBOL(ecc_get_curve25519);
52
53const struct ecc_curve *ecc_get_curve(unsigned int curve_id)
54{
55 switch (curve_id) {
56
57 case ECC_CURVE_NIST_P192:
58 return fips_enabled ? NULL : &nist_p192;
59 case ECC_CURVE_NIST_P256:
60 return &nist_p256;
61 case ECC_CURVE_NIST_P384:
62 return &nist_p384;
63 default:
64 return NULL;
65 }
66}
67EXPORT_SYMBOL(ecc_get_curve);
68
69static u64 *ecc_alloc_digits_space(unsigned int ndigits)
70{
71 size_t len = ndigits * sizeof(u64);
72
73 if (!len)
74 return NULL;
75
76 return kmalloc(len, GFP_KERNEL);
77}
78
79static void ecc_free_digits_space(u64 *space)
80{
81 kfree_sensitive(space);
82}
83
84static struct ecc_point *ecc_alloc_point(unsigned int ndigits)
85{
86 struct ecc_point *p = kmalloc(sizeof(*p), GFP_KERNEL);
87
88 if (!p)
89 return NULL;
90
91 p->x = ecc_alloc_digits_space(ndigits);
92 if (!p->x)
93 goto err_alloc_x;
94
95 p->y = ecc_alloc_digits_space(ndigits);
96 if (!p->y)
97 goto err_alloc_y;
98
99 p->ndigits = ndigits;
100
101 return p;
102
103err_alloc_y:
104 ecc_free_digits_space(p->x);
105err_alloc_x:
106 kfree(p);
107 return NULL;
108}
109
110static void ecc_free_point(struct ecc_point *p)
111{
112 if (!p)
113 return;
114
115 kfree_sensitive(p->x);
116 kfree_sensitive(p->y);
117 kfree_sensitive(p);
118}
119
120static void vli_clear(u64 *vli, unsigned int ndigits)
121{
122 int i;
123
124 for (i = 0; i < ndigits; i++)
125 vli[i] = 0;
126}
127
128
129bool vli_is_zero(const u64 *vli, unsigned int ndigits)
130{
131 int i;
132
133 for (i = 0; i < ndigits; i++) {
134 if (vli[i])
135 return false;
136 }
137
138 return true;
139}
140EXPORT_SYMBOL(vli_is_zero);
141
142
143static u64 vli_test_bit(const u64 *vli, unsigned int bit)
144{
145 return (vli[bit / 64] & ((u64)1 << (bit % 64)));
146}
147
148static bool vli_is_negative(const u64 *vli, unsigned int ndigits)
149{
150 return vli_test_bit(vli, ndigits * 64 - 1);
151}
152
153
154static unsigned int vli_num_digits(const u64 *vli, unsigned int ndigits)
155{
156 int i;
157
158
159
160
161
162 for (i = ndigits - 1; i >= 0 && vli[i] == 0; i--);
163
164 return (i + 1);
165}
166
167
168static unsigned int vli_num_bits(const u64 *vli, unsigned int ndigits)
169{
170 unsigned int i, num_digits;
171 u64 digit;
172
173 num_digits = vli_num_digits(vli, ndigits);
174 if (num_digits == 0)
175 return 0;
176
177 digit = vli[num_digits - 1];
178 for (i = 0; digit; i++)
179 digit >>= 1;
180
181 return ((num_digits - 1) * 64 + i);
182}
183
184
185void vli_from_be64(u64 *dest, const void *src, unsigned int ndigits)
186{
187 int i;
188 const u64 *from = src;
189
190 for (i = 0; i < ndigits; i++)
191 dest[i] = get_unaligned_be64(&from[ndigits - 1 - i]);
192}
193EXPORT_SYMBOL(vli_from_be64);
194
195void vli_from_le64(u64 *dest, const void *src, unsigned int ndigits)
196{
197 int i;
198 const u64 *from = src;
199
200 for (i = 0; i < ndigits; i++)
201 dest[i] = get_unaligned_le64(&from[i]);
202}
203EXPORT_SYMBOL(vli_from_le64);
204
205
206static void vli_set(u64 *dest, const u64 *src, unsigned int ndigits)
207{
208 int i;
209
210 for (i = 0; i < ndigits; i++)
211 dest[i] = src[i];
212}
213
214
215int vli_cmp(const u64 *left, const u64 *right, unsigned int ndigits)
216{
217 int i;
218
219 for (i = ndigits - 1; i >= 0; i--) {
220 if (left[i] > right[i])
221 return 1;
222 else if (left[i] < right[i])
223 return -1;
224 }
225
226 return 0;
227}
228EXPORT_SYMBOL(vli_cmp);
229
230
231
232
233static u64 vli_lshift(u64 *result, const u64 *in, unsigned int shift,
234 unsigned int ndigits)
235{
236 u64 carry = 0;
237 int i;
238
239 for (i = 0; i < ndigits; i++) {
240 u64 temp = in[i];
241
242 result[i] = (temp << shift) | carry;
243 carry = temp >> (64 - shift);
244 }
245
246 return carry;
247}
248
249
250static void vli_rshift1(u64 *vli, unsigned int ndigits)
251{
252 u64 *end = vli;
253 u64 carry = 0;
254
255 vli += ndigits;
256
257 while (vli-- > end) {
258 u64 temp = *vli;
259 *vli = (temp >> 1) | carry;
260 carry = temp << 63;
261 }
262}
263
264
265static u64 vli_add(u64 *result, const u64 *left, const u64 *right,
266 unsigned int ndigits)
267{
268 u64 carry = 0;
269 int i;
270
271 for (i = 0; i < ndigits; i++) {
272 u64 sum;
273
274 sum = left[i] + right[i] + carry;
275 if (sum != left[i])
276 carry = (sum < left[i]);
277
278 result[i] = sum;
279 }
280
281 return carry;
282}
283
284
285static u64 vli_uadd(u64 *result, const u64 *left, u64 right,
286 unsigned int ndigits)
287{
288 u64 carry = right;
289 int i;
290
291 for (i = 0; i < ndigits; i++) {
292 u64 sum;
293
294 sum = left[i] + carry;
295 if (sum != left[i])
296 carry = (sum < left[i]);
297 else
298 carry = !!carry;
299
300 result[i] = sum;
301 }
302
303 return carry;
304}
305
306
307u64 vli_sub(u64 *result, const u64 *left, const u64 *right,
308 unsigned int ndigits)
309{
310 u64 borrow = 0;
311 int i;
312
313 for (i = 0; i < ndigits; i++) {
314 u64 diff;
315
316 diff = left[i] - right[i] - borrow;
317 if (diff != left[i])
318 borrow = (diff > left[i]);
319
320 result[i] = diff;
321 }
322
323 return borrow;
324}
325EXPORT_SYMBOL(vli_sub);
326
327
328static u64 vli_usub(u64 *result, const u64 *left, u64 right,
329 unsigned int ndigits)
330{
331 u64 borrow = right;
332 int i;
333
334 for (i = 0; i < ndigits; i++) {
335 u64 diff;
336
337 diff = left[i] - borrow;
338 if (diff != left[i])
339 borrow = (diff > left[i]);
340
341 result[i] = diff;
342 }
343
344 return borrow;
345}
346
347static uint128_t mul_64_64(u64 left, u64 right)
348{
349 uint128_t result;
350#if defined(CONFIG_ARCH_SUPPORTS_INT128)
351 unsigned __int128 m = (unsigned __int128)left * right;
352
353 result.m_low = m;
354 result.m_high = m >> 64;
355#else
356 u64 a0 = left & 0xffffffffull;
357 u64 a1 = left >> 32;
358 u64 b0 = right & 0xffffffffull;
359 u64 b1 = right >> 32;
360 u64 m0 = a0 * b0;
361 u64 m1 = a0 * b1;
362 u64 m2 = a1 * b0;
363 u64 m3 = a1 * b1;
364
365 m2 += (m0 >> 32);
366 m2 += m1;
367
368
369 if (m2 < m1)
370 m3 += 0x100000000ull;
371
372 result.m_low = (m0 & 0xffffffffull) | (m2 << 32);
373 result.m_high = m3 + (m2 >> 32);
374#endif
375 return result;
376}
377
378static uint128_t add_128_128(uint128_t a, uint128_t b)
379{
380 uint128_t result;
381
382 result.m_low = a.m_low + b.m_low;
383 result.m_high = a.m_high + b.m_high + (result.m_low < a.m_low);
384
385 return result;
386}
387
388static void vli_mult(u64 *result, const u64 *left, const u64 *right,
389 unsigned int ndigits)
390{
391 uint128_t r01 = { 0, 0 };
392 u64 r2 = 0;
393 unsigned int i, k;
394
395
396
397
398 for (k = 0; k < ndigits * 2 - 1; k++) {
399 unsigned int min;
400
401 if (k < ndigits)
402 min = 0;
403 else
404 min = (k + 1) - ndigits;
405
406 for (i = min; i <= k && i < ndigits; i++) {
407 uint128_t product;
408
409 product = mul_64_64(left[i], right[k - i]);
410
411 r01 = add_128_128(r01, product);
412 r2 += (r01.m_high < product.m_high);
413 }
414
415 result[k] = r01.m_low;
416 r01.m_low = r01.m_high;
417 r01.m_high = r2;
418 r2 = 0;
419 }
420
421 result[ndigits * 2 - 1] = r01.m_low;
422}
423
424
425static void vli_umult(u64 *result, const u64 *left, u32 right,
426 unsigned int ndigits)
427{
428 uint128_t r01 = { 0 };
429 unsigned int k;
430
431 for (k = 0; k < ndigits; k++) {
432 uint128_t product;
433
434 product = mul_64_64(left[k], right);
435 r01 = add_128_128(r01, product);
436
437 result[k] = r01.m_low;
438 r01.m_low = r01.m_high;
439 r01.m_high = 0;
440 }
441 result[k] = r01.m_low;
442 for (++k; k < ndigits * 2; k++)
443 result[k] = 0;
444}
445
446static void vli_square(u64 *result, const u64 *left, unsigned int ndigits)
447{
448 uint128_t r01 = { 0, 0 };
449 u64 r2 = 0;
450 int i, k;
451
452 for (k = 0; k < ndigits * 2 - 1; k++) {
453 unsigned int min;
454
455 if (k < ndigits)
456 min = 0;
457 else
458 min = (k + 1) - ndigits;
459
460 for (i = min; i <= k && i <= k - i; i++) {
461 uint128_t product;
462
463 product = mul_64_64(left[i], left[k - i]);
464
465 if (i < k - i) {
466 r2 += product.m_high >> 63;
467 product.m_high = (product.m_high << 1) |
468 (product.m_low >> 63);
469 product.m_low <<= 1;
470 }
471
472 r01 = add_128_128(r01, product);
473 r2 += (r01.m_high < product.m_high);
474 }
475
476 result[k] = r01.m_low;
477 r01.m_low = r01.m_high;
478 r01.m_high = r2;
479 r2 = 0;
480 }
481
482 result[ndigits * 2 - 1] = r01.m_low;
483}
484
485
486
487
488static void vli_mod_add(u64 *result, const u64 *left, const u64 *right,
489 const u64 *mod, unsigned int ndigits)
490{
491 u64 carry;
492
493 carry = vli_add(result, left, right, ndigits);
494
495
496
497
498 if (carry || vli_cmp(result, mod, ndigits) >= 0)
499 vli_sub(result, result, mod, ndigits);
500}
501
502
503
504
505static void vli_mod_sub(u64 *result, const u64 *left, const u64 *right,
506 const u64 *mod, unsigned int ndigits)
507{
508 u64 borrow = vli_sub(result, left, right, ndigits);
509
510
511
512
513
514 if (borrow)
515 vli_add(result, result, mod, ndigits);
516}
517
518
519
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525
526
527static void vli_mmod_special(u64 *result, const u64 *product,
528 const u64 *mod, unsigned int ndigits)
529{
530 u64 c = -mod[0];
531 u64 t[ECC_MAX_DIGITS * 2];
532 u64 r[ECC_MAX_DIGITS * 2];
533
534 vli_set(r, product, ndigits * 2);
535 while (!vli_is_zero(r + ndigits, ndigits)) {
536 vli_umult(t, r + ndigits, c, ndigits);
537 vli_clear(r + ndigits, ndigits);
538 vli_add(r, r, t, ndigits * 2);
539 }
540 vli_set(t, mod, ndigits);
541 vli_clear(t + ndigits, ndigits);
542 while (vli_cmp(r, t, ndigits * 2) >= 0)
543 vli_sub(r, r, t, ndigits * 2);
544 vli_set(result, r, ndigits);
545}
546
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556
557
558
559
560
561static void vli_mmod_special2(u64 *result, const u64 *product,
562 const u64 *mod, unsigned int ndigits)
563{
564 u64 c2 = mod[0] * 2;
565 u64 q[ECC_MAX_DIGITS];
566 u64 r[ECC_MAX_DIGITS * 2];
567 u64 m[ECC_MAX_DIGITS * 2];
568 int carry;
569 int i;
570
571 vli_set(m, mod, ndigits);
572 vli_clear(m + ndigits, ndigits);
573
574 vli_set(r, product, ndigits);
575
576 vli_set(q, product + ndigits, ndigits);
577 vli_clear(r + ndigits, ndigits);
578 carry = vli_is_negative(r, ndigits);
579 if (carry)
580 r[ndigits - 1] &= (1ull << 63) - 1;
581 for (i = 1; carry || !vli_is_zero(q, ndigits); i++) {
582 u64 qc[ECC_MAX_DIGITS * 2];
583
584 vli_umult(qc, q, c2, ndigits);
585 if (carry)
586 vli_uadd(qc, qc, mod[0], ndigits * 2);
587 vli_set(q, qc + ndigits, ndigits);
588 vli_clear(qc + ndigits, ndigits);
589 carry = vli_is_negative(qc, ndigits);
590 if (carry)
591 qc[ndigits - 1] &= (1ull << 63) - 1;
592 if (i & 1)
593 vli_sub(r, r, qc, ndigits * 2);
594 else
595 vli_add(r, r, qc, ndigits * 2);
596 }
597 while (vli_is_negative(r, ndigits * 2))
598 vli_add(r, r, m, ndigits * 2);
599 while (vli_cmp(r, m, ndigits * 2) >= 0)
600 vli_sub(r, r, m, ndigits * 2);
601
602 vli_set(result, r, ndigits);
603}
604
605
606
607
608
609
610static void vli_mmod_slow(u64 *result, u64 *product, const u64 *mod,
611 unsigned int ndigits)
612{
613 u64 mod_m[2 * ECC_MAX_DIGITS];
614 u64 tmp[2 * ECC_MAX_DIGITS];
615 u64 *v[2] = { tmp, product };
616 u64 carry = 0;
617 unsigned int i;
618
619 int shift = (ndigits * 2 * 64) - vli_num_bits(mod, ndigits);
620 int word_shift = shift / 64;
621 int bit_shift = shift % 64;
622
623 vli_clear(mod_m, word_shift);
624 if (bit_shift > 0) {
625 for (i = 0; i < ndigits; ++i) {
626 mod_m[word_shift + i] = (mod[i] << bit_shift) | carry;
627 carry = mod[i] >> (64 - bit_shift);
628 }
629 } else
630 vli_set(mod_m + word_shift, mod, ndigits);
631
632 for (i = 1; shift >= 0; --shift) {
633 u64 borrow = 0;
634 unsigned int j;
635
636 for (j = 0; j < ndigits * 2; ++j) {
637 u64 diff = v[i][j] - mod_m[j] - borrow;
638
639 if (diff != v[i][j])
640 borrow = (diff > v[i][j]);
641 v[1 - i][j] = diff;
642 }
643 i = !(i ^ borrow);
644 vli_rshift1(mod_m, ndigits);
645 mod_m[ndigits - 1] |= mod_m[ndigits] << (64 - 1);
646 vli_rshift1(mod_m + ndigits, ndigits);
647 }
648 vli_set(result, v[i], ndigits);
649}
650
651
652
653
654
655
656
657
658
659
660static void vli_mmod_barrett(u64 *result, u64 *product, const u64 *mod,
661 unsigned int ndigits)
662{
663 u64 q[ECC_MAX_DIGITS * 2];
664 u64 r[ECC_MAX_DIGITS * 2];
665 const u64 *mu = mod + ndigits;
666
667 vli_mult(q, product + ndigits, mu, ndigits);
668 if (mu[ndigits])
669 vli_add(q + ndigits, q + ndigits, product + ndigits, ndigits);
670 vli_mult(r, mod, q + ndigits, ndigits);
671 vli_sub(r, product, r, ndigits * 2);
672 while (!vli_is_zero(r + ndigits, ndigits) ||
673 vli_cmp(r, mod, ndigits) != -1) {
674 u64 carry;
675
676 carry = vli_sub(r, r, mod, ndigits);
677 vli_usub(r + ndigits, r + ndigits, carry, ndigits);
678 }
679 vli_set(result, r, ndigits);
680}
681
682
683
684
685
686static void vli_mmod_fast_192(u64 *result, const u64 *product,
687 const u64 *curve_prime, u64 *tmp)
688{
689 const unsigned int ndigits = 3;
690 int carry;
691
692 vli_set(result, product, ndigits);
693
694 vli_set(tmp, &product[3], ndigits);
695 carry = vli_add(result, result, tmp, ndigits);
696
697 tmp[0] = 0;
698 tmp[1] = product[3];
699 tmp[2] = product[4];
700 carry += vli_add(result, result, tmp, ndigits);
701
702 tmp[0] = tmp[1] = product[5];
703 tmp[2] = 0;
704 carry += vli_add(result, result, tmp, ndigits);
705
706 while (carry || vli_cmp(curve_prime, result, ndigits) != 1)
707 carry -= vli_sub(result, result, curve_prime, ndigits);
708}
709
710
711
712
713static void vli_mmod_fast_256(u64 *result, const u64 *product,
714 const u64 *curve_prime, u64 *tmp)
715{
716 int carry;
717 const unsigned int ndigits = 4;
718
719
720 vli_set(result, product, ndigits);
721
722
723 tmp[0] = 0;
724 tmp[1] = product[5] & 0xffffffff00000000ull;
725 tmp[2] = product[6];
726 tmp[3] = product[7];
727 carry = vli_lshift(tmp, tmp, 1, ndigits);
728 carry += vli_add(result, result, tmp, ndigits);
729
730
731 tmp[1] = product[6] << 32;
732 tmp[2] = (product[6] >> 32) | (product[7] << 32);
733 tmp[3] = product[7] >> 32;
734 carry += vli_lshift(tmp, tmp, 1, ndigits);
735 carry += vli_add(result, result, tmp, ndigits);
736
737
738 tmp[0] = product[4];
739 tmp[1] = product[5] & 0xffffffff;
740 tmp[2] = 0;
741 tmp[3] = product[7];
742 carry += vli_add(result, result, tmp, ndigits);
743
744
745 tmp[0] = (product[4] >> 32) | (product[5] << 32);
746 tmp[1] = (product[5] >> 32) | (product[6] & 0xffffffff00000000ull);
747 tmp[2] = product[7];
748 tmp[3] = (product[6] >> 32) | (product[4] << 32);
749 carry += vli_add(result, result, tmp, ndigits);
750
751
752 tmp[0] = (product[5] >> 32) | (product[6] << 32);
753 tmp[1] = (product[6] >> 32);
754 tmp[2] = 0;
755 tmp[3] = (product[4] & 0xffffffff) | (product[5] << 32);
756 carry -= vli_sub(result, result, tmp, ndigits);
757
758
759 tmp[0] = product[6];
760 tmp[1] = product[7];
761 tmp[2] = 0;
762 tmp[3] = (product[4] >> 32) | (product[5] & 0xffffffff00000000ull);
763 carry -= vli_sub(result, result, tmp, ndigits);
764
765
766 tmp[0] = (product[6] >> 32) | (product[7] << 32);
767 tmp[1] = (product[7] >> 32) | (product[4] << 32);
768 tmp[2] = (product[4] >> 32) | (product[5] << 32);
769 tmp[3] = (product[6] << 32);
770 carry -= vli_sub(result, result, tmp, ndigits);
771
772
773 tmp[0] = product[7];
774 tmp[1] = product[4] & 0xffffffff00000000ull;
775 tmp[2] = product[5];
776 tmp[3] = product[6] & 0xffffffff00000000ull;
777 carry -= vli_sub(result, result, tmp, ndigits);
778
779 if (carry < 0) {
780 do {
781 carry += vli_add(result, result, curve_prime, ndigits);
782 } while (carry < 0);
783 } else {
784 while (carry || vli_cmp(curve_prime, result, ndigits) != 1)
785 carry -= vli_sub(result, result, curve_prime, ndigits);
786 }
787}
788
789#define SL32OR32(x32, y32) (((u64)x32 << 32) | y32)
790#define AND64H(x64) (x64 & 0xffFFffFF00000000ull)
791#define AND64L(x64) (x64 & 0x00000000ffFFffFFull)
792
793
794
795
796static void vli_mmod_fast_384(u64 *result, const u64 *product,
797 const u64 *curve_prime, u64 *tmp)
798{
799 int carry;
800 const unsigned int ndigits = 6;
801
802
803 vli_set(result, product, ndigits);
804
805
806 tmp[0] = 0;
807 tmp[1] = 0;
808 tmp[2] = SL32OR32(product[11], (product[10]>>32));
809 tmp[3] = product[11]>>32;
810 tmp[4] = 0;
811 tmp[5] = 0;
812 carry = vli_lshift(tmp, tmp, 1, ndigits);
813 carry += vli_add(result, result, tmp, ndigits);
814
815
816 tmp[0] = product[6];
817 tmp[1] = product[7];
818 tmp[2] = product[8];
819 tmp[3] = product[9];
820 tmp[4] = product[10];
821 tmp[5] = product[11];
822 carry += vli_add(result, result, tmp, ndigits);
823
824
825 tmp[0] = SL32OR32(product[11], (product[10]>>32));
826 tmp[1] = SL32OR32(product[6], (product[11]>>32));
827 tmp[2] = SL32OR32(product[7], (product[6])>>32);
828 tmp[3] = SL32OR32(product[8], (product[7]>>32));
829 tmp[4] = SL32OR32(product[9], (product[8]>>32));
830 tmp[5] = SL32OR32(product[10], (product[9]>>32));
831 carry += vli_add(result, result, tmp, ndigits);
832
833
834 tmp[0] = AND64H(product[11]);
835 tmp[1] = (product[10]<<32);
836 tmp[2] = product[6];
837 tmp[3] = product[7];
838 tmp[4] = product[8];
839 tmp[5] = product[9];
840 carry += vli_add(result, result, tmp, ndigits);
841
842
843 tmp[0] = 0;
844 tmp[1] = 0;
845 tmp[2] = product[10];
846 tmp[3] = product[11];
847 tmp[4] = 0;
848 tmp[5] = 0;
849 carry += vli_add(result, result, tmp, ndigits);
850
851
852 tmp[0] = AND64L(product[10]);
853 tmp[1] = AND64H(product[10]);
854 tmp[2] = product[11];
855 tmp[3] = 0;
856 tmp[4] = 0;
857 tmp[5] = 0;
858 carry += vli_add(result, result, tmp, ndigits);
859
860
861 tmp[0] = SL32OR32(product[6], (product[11]>>32));
862 tmp[1] = SL32OR32(product[7], (product[6]>>32));
863 tmp[2] = SL32OR32(product[8], (product[7]>>32));
864 tmp[3] = SL32OR32(product[9], (product[8]>>32));
865 tmp[4] = SL32OR32(product[10], (product[9]>>32));
866 tmp[5] = SL32OR32(product[11], (product[10]>>32));
867 carry -= vli_sub(result, result, tmp, ndigits);
868
869
870 tmp[0] = (product[10]<<32);
871 tmp[1] = SL32OR32(product[11], (product[10]>>32));
872 tmp[2] = (product[11]>>32);
873 tmp[3] = 0;
874 tmp[4] = 0;
875 tmp[5] = 0;
876 carry -= vli_sub(result, result, tmp, ndigits);
877
878
879 tmp[0] = 0;
880 tmp[1] = AND64H(product[11]);
881 tmp[2] = product[11]>>32;
882 tmp[3] = 0;
883 tmp[4] = 0;
884 tmp[5] = 0;
885 carry -= vli_sub(result, result, tmp, ndigits);
886
887 if (carry < 0) {
888 do {
889 carry += vli_add(result, result, curve_prime, ndigits);
890 } while (carry < 0);
891 } else {
892 while (carry || vli_cmp(curve_prime, result, ndigits) != 1)
893 carry -= vli_sub(result, result, curve_prime, ndigits);
894 }
895
896}
897
898#undef SL32OR32
899#undef AND64H
900#undef AND64L
901
902
903
904
905
906
907static bool vli_mmod_fast(u64 *result, u64 *product,
908 const struct ecc_curve *curve)
909{
910 u64 tmp[2 * ECC_MAX_DIGITS];
911 const u64 *curve_prime = curve->p;
912 const unsigned int ndigits = curve->g.ndigits;
913
914
915 if (strncmp(curve->name, "nist_", 5) != 0) {
916
917 if (curve_prime[ndigits - 1] == -1ull) {
918 vli_mmod_special(result, product, curve_prime,
919 ndigits);
920 return true;
921 } else if (curve_prime[ndigits - 1] == 1ull << 63 &&
922 curve_prime[ndigits - 2] == 0) {
923 vli_mmod_special2(result, product, curve_prime,
924 ndigits);
925 return true;
926 }
927 vli_mmod_barrett(result, product, curve_prime, ndigits);
928 return true;
929 }
930
931 switch (ndigits) {
932 case 3:
933 vli_mmod_fast_192(result, product, curve_prime, tmp);
934 break;
935 case 4:
936 vli_mmod_fast_256(result, product, curve_prime, tmp);
937 break;
938 case 6:
939 vli_mmod_fast_384(result, product, curve_prime, tmp);
940 break;
941 default:
942 pr_err_ratelimited("ecc: unsupported digits size!\n");
943 return false;
944 }
945
946 return true;
947}
948
949
950
951
952void vli_mod_mult_slow(u64 *result, const u64 *left, const u64 *right,
953 const u64 *mod, unsigned int ndigits)
954{
955 u64 product[ECC_MAX_DIGITS * 2];
956
957 vli_mult(product, left, right, ndigits);
958 vli_mmod_slow(result, product, mod, ndigits);
959}
960EXPORT_SYMBOL(vli_mod_mult_slow);
961
962
963static void vli_mod_mult_fast(u64 *result, const u64 *left, const u64 *right,
964 const struct ecc_curve *curve)
965{
966 u64 product[2 * ECC_MAX_DIGITS];
967
968 vli_mult(product, left, right, curve->g.ndigits);
969 vli_mmod_fast(result, product, curve);
970}
971
972
973static void vli_mod_square_fast(u64 *result, const u64 *left,
974 const struct ecc_curve *curve)
975{
976 u64 product[2 * ECC_MAX_DIGITS];
977
978 vli_square(product, left, curve->g.ndigits);
979 vli_mmod_fast(result, product, curve);
980}
981
982#define EVEN(vli) (!(vli[0] & 1))
983
984
985
986
987void vli_mod_inv(u64 *result, const u64 *input, const u64 *mod,
988 unsigned int ndigits)
989{
990 u64 a[ECC_MAX_DIGITS], b[ECC_MAX_DIGITS];
991 u64 u[ECC_MAX_DIGITS], v[ECC_MAX_DIGITS];
992 u64 carry;
993 int cmp_result;
994
995 if (vli_is_zero(input, ndigits)) {
996 vli_clear(result, ndigits);
997 return;
998 }
999
1000 vli_set(a, input, ndigits);
1001 vli_set(b, mod, ndigits);
1002 vli_clear(u, ndigits);
1003 u[0] = 1;
1004 vli_clear(v, ndigits);
1005
1006 while ((cmp_result = vli_cmp(a, b, ndigits)) != 0) {
1007 carry = 0;
1008
1009 if (EVEN(a)) {
1010 vli_rshift1(a, ndigits);
1011
1012 if (!EVEN(u))
1013 carry = vli_add(u, u, mod, ndigits);
1014
1015 vli_rshift1(u, ndigits);
1016 if (carry)
1017 u[ndigits - 1] |= 0x8000000000000000ull;
1018 } else if (EVEN(b)) {
1019 vli_rshift1(b, ndigits);
1020
1021 if (!EVEN(v))
1022 carry = vli_add(v, v, mod, ndigits);
1023
1024 vli_rshift1(v, ndigits);
1025 if (carry)
1026 v[ndigits - 1] |= 0x8000000000000000ull;
1027 } else if (cmp_result > 0) {
1028 vli_sub(a, a, b, ndigits);
1029 vli_rshift1(a, ndigits);
1030
1031 if (vli_cmp(u, v, ndigits) < 0)
1032 vli_add(u, u, mod, ndigits);
1033
1034 vli_sub(u, u, v, ndigits);
1035 if (!EVEN(u))
1036 carry = vli_add(u, u, mod, ndigits);
1037
1038 vli_rshift1(u, ndigits);
1039 if (carry)
1040 u[ndigits - 1] |= 0x8000000000000000ull;
1041 } else {
1042 vli_sub(b, b, a, ndigits);
1043 vli_rshift1(b, ndigits);
1044
1045 if (vli_cmp(v, u, ndigits) < 0)
1046 vli_add(v, v, mod, ndigits);
1047
1048 vli_sub(v, v, u, ndigits);
1049 if (!EVEN(v))
1050 carry = vli_add(v, v, mod, ndigits);
1051
1052 vli_rshift1(v, ndigits);
1053 if (carry)
1054 v[ndigits - 1] |= 0x8000000000000000ull;
1055 }
1056 }
1057
1058 vli_set(result, u, ndigits);
1059}
1060EXPORT_SYMBOL(vli_mod_inv);
1061
1062
1063
1064
1065static bool ecc_point_is_zero(const struct ecc_point *point)
1066{
1067 return (vli_is_zero(point->x, point->ndigits) &&
1068 vli_is_zero(point->y, point->ndigits));
1069}
1070
1071
1072
1073
1074
1075
1076static void ecc_point_double_jacobian(u64 *x1, u64 *y1, u64 *z1,
1077 const struct ecc_curve *curve)
1078{
1079
1080 u64 t4[ECC_MAX_DIGITS];
1081 u64 t5[ECC_MAX_DIGITS];
1082 const u64 *curve_prime = curve->p;
1083 const unsigned int ndigits = curve->g.ndigits;
1084
1085 if (vli_is_zero(z1, ndigits))
1086 return;
1087
1088
1089 vli_mod_square_fast(t4, y1, curve);
1090
1091 vli_mod_mult_fast(t5, x1, t4, curve);
1092
1093 vli_mod_square_fast(t4, t4, curve);
1094
1095 vli_mod_mult_fast(y1, y1, z1, curve);
1096
1097 vli_mod_square_fast(z1, z1, curve);
1098
1099
1100 vli_mod_add(x1, x1, z1, curve_prime, ndigits);
1101
1102 vli_mod_add(z1, z1, z1, curve_prime, ndigits);
1103
1104 vli_mod_sub(z1, x1, z1, curve_prime, ndigits);
1105
1106 vli_mod_mult_fast(x1, x1, z1, curve);
1107
1108
1109 vli_mod_add(z1, x1, x1, curve_prime, ndigits);
1110
1111 vli_mod_add(x1, x1, z1, curve_prime, ndigits);
1112 if (vli_test_bit(x1, 0)) {
1113 u64 carry = vli_add(x1, x1, curve_prime, ndigits);
1114
1115 vli_rshift1(x1, ndigits);
1116 x1[ndigits - 1] |= carry << 63;
1117 } else {
1118 vli_rshift1(x1, ndigits);
1119 }
1120
1121
1122
1123 vli_mod_square_fast(z1, x1, curve);
1124
1125 vli_mod_sub(z1, z1, t5, curve_prime, ndigits);
1126
1127 vli_mod_sub(z1, z1, t5, curve_prime, ndigits);
1128
1129 vli_mod_sub(t5, t5, z1, curve_prime, ndigits);
1130
1131 vli_mod_mult_fast(x1, x1, t5, curve);
1132
1133 vli_mod_sub(t4, x1, t4, curve_prime, ndigits);
1134
1135 vli_set(x1, z1, ndigits);
1136 vli_set(z1, y1, ndigits);
1137 vli_set(y1, t4, ndigits);
1138}
1139
1140
1141static void apply_z(u64 *x1, u64 *y1, u64 *z, const struct ecc_curve *curve)
1142{
1143 u64 t1[ECC_MAX_DIGITS];
1144
1145 vli_mod_square_fast(t1, z, curve);
1146 vli_mod_mult_fast(x1, x1, t1, curve);
1147 vli_mod_mult_fast(t1, t1, z, curve);
1148 vli_mod_mult_fast(y1, y1, t1, curve);
1149}
1150
1151
1152static void xycz_initial_double(u64 *x1, u64 *y1, u64 *x2, u64 *y2,
1153 u64 *p_initial_z, const struct ecc_curve *curve)
1154{
1155 u64 z[ECC_MAX_DIGITS];
1156 const unsigned int ndigits = curve->g.ndigits;
1157
1158 vli_set(x2, x1, ndigits);
1159 vli_set(y2, y1, ndigits);
1160
1161 vli_clear(z, ndigits);
1162 z[0] = 1;
1163
1164 if (p_initial_z)
1165 vli_set(z, p_initial_z, ndigits);
1166
1167 apply_z(x1, y1, z, curve);
1168
1169 ecc_point_double_jacobian(x1, y1, z, curve);
1170
1171 apply_z(x2, y2, z, curve);
1172}
1173
1174
1175
1176
1177
1178static void xycz_add(u64 *x1, u64 *y1, u64 *x2, u64 *y2,
1179 const struct ecc_curve *curve)
1180{
1181
1182 u64 t5[ECC_MAX_DIGITS];
1183 const u64 *curve_prime = curve->p;
1184 const unsigned int ndigits = curve->g.ndigits;
1185
1186
1187 vli_mod_sub(t5, x2, x1, curve_prime, ndigits);
1188
1189 vli_mod_square_fast(t5, t5, curve);
1190
1191 vli_mod_mult_fast(x1, x1, t5, curve);
1192
1193 vli_mod_mult_fast(x2, x2, t5, curve);
1194
1195 vli_mod_sub(y2, y2, y1, curve_prime, ndigits);
1196
1197 vli_mod_square_fast(t5, y2, curve);
1198
1199
1200 vli_mod_sub(t5, t5, x1, curve_prime, ndigits);
1201
1202 vli_mod_sub(t5, t5, x2, curve_prime, ndigits);
1203
1204 vli_mod_sub(x2, x2, x1, curve_prime, ndigits);
1205
1206 vli_mod_mult_fast(y1, y1, x2, curve);
1207
1208 vli_mod_sub(x2, x1, t5, curve_prime, ndigits);
1209
1210 vli_mod_mult_fast(y2, y2, x2, curve);
1211
1212 vli_mod_sub(y2, y2, y1, curve_prime, ndigits);
1213
1214 vli_set(x2, t5, ndigits);
1215}
1216
1217
1218
1219
1220
1221static void xycz_add_c(u64 *x1, u64 *y1, u64 *x2, u64 *y2,
1222 const struct ecc_curve *curve)
1223{
1224
1225 u64 t5[ECC_MAX_DIGITS];
1226 u64 t6[ECC_MAX_DIGITS];
1227 u64 t7[ECC_MAX_DIGITS];
1228 const u64 *curve_prime = curve->p;
1229 const unsigned int ndigits = curve->g.ndigits;
1230
1231
1232 vli_mod_sub(t5, x2, x1, curve_prime, ndigits);
1233
1234 vli_mod_square_fast(t5, t5, curve);
1235
1236 vli_mod_mult_fast(x1, x1, t5, curve);
1237
1238 vli_mod_mult_fast(x2, x2, t5, curve);
1239
1240 vli_mod_add(t5, y2, y1, curve_prime, ndigits);
1241
1242 vli_mod_sub(y2, y2, y1, curve_prime, ndigits);
1243
1244
1245 vli_mod_sub(t6, x2, x1, curve_prime, ndigits);
1246
1247 vli_mod_mult_fast(y1, y1, t6, curve);
1248
1249 vli_mod_add(t6, x1, x2, curve_prime, ndigits);
1250
1251 vli_mod_square_fast(x2, y2, curve);
1252
1253 vli_mod_sub(x2, x2, t6, curve_prime, ndigits);
1254
1255
1256 vli_mod_sub(t7, x1, x2, curve_prime, ndigits);
1257
1258 vli_mod_mult_fast(y2, y2, t7, curve);
1259
1260 vli_mod_sub(y2, y2, y1, curve_prime, ndigits);
1261
1262
1263 vli_mod_square_fast(t7, t5, curve);
1264
1265 vli_mod_sub(t7, t7, t6, curve_prime, ndigits);
1266
1267 vli_mod_sub(t6, t7, x1, curve_prime, ndigits);
1268
1269 vli_mod_mult_fast(t6, t6, t5, curve);
1270
1271 vli_mod_sub(y1, t6, y1, curve_prime, ndigits);
1272
1273 vli_set(x1, t7, ndigits);
1274}
1275
1276static void ecc_point_mult(struct ecc_point *result,
1277 const struct ecc_point *point, const u64 *scalar,
1278 u64 *initial_z, const struct ecc_curve *curve,
1279 unsigned int ndigits)
1280{
1281
1282 u64 rx[2][ECC_MAX_DIGITS];
1283 u64 ry[2][ECC_MAX_DIGITS];
1284 u64 z[ECC_MAX_DIGITS];
1285 u64 sk[2][ECC_MAX_DIGITS];
1286 u64 *curve_prime = curve->p;
1287 int i, nb;
1288 int num_bits;
1289 int carry;
1290
1291 carry = vli_add(sk[0], scalar, curve->n, ndigits);
1292 vli_add(sk[1], sk[0], curve->n, ndigits);
1293 scalar = sk[!carry];
1294 num_bits = sizeof(u64) * ndigits * 8 + 1;
1295
1296 vli_set(rx[1], point->x, ndigits);
1297 vli_set(ry[1], point->y, ndigits);
1298
1299 xycz_initial_double(rx[1], ry[1], rx[0], ry[0], initial_z, curve);
1300
1301 for (i = num_bits - 2; i > 0; i--) {
1302 nb = !vli_test_bit(scalar, i);
1303 xycz_add_c(rx[1 - nb], ry[1 - nb], rx[nb], ry[nb], curve);
1304 xycz_add(rx[nb], ry[nb], rx[1 - nb], ry[1 - nb], curve);
1305 }
1306
1307 nb = !vli_test_bit(scalar, 0);
1308 xycz_add_c(rx[1 - nb], ry[1 - nb], rx[nb], ry[nb], curve);
1309
1310
1311
1312 vli_mod_sub(z, rx[1], rx[0], curve_prime, ndigits);
1313
1314 vli_mod_mult_fast(z, z, ry[1 - nb], curve);
1315
1316 vli_mod_mult_fast(z, z, point->x, curve);
1317
1318
1319 vli_mod_inv(z, z, curve_prime, point->ndigits);
1320
1321
1322 vli_mod_mult_fast(z, z, point->y, curve);
1323
1324 vli_mod_mult_fast(z, z, rx[1 - nb], curve);
1325
1326
1327 xycz_add(rx[nb], ry[nb], rx[1 - nb], ry[1 - nb], curve);
1328
1329 apply_z(rx[0], ry[0], z, curve);
1330
1331 vli_set(result->x, rx[0], ndigits);
1332 vli_set(result->y, ry[0], ndigits);
1333}
1334
1335
1336static void ecc_point_add(const struct ecc_point *result,
1337 const struct ecc_point *p, const struct ecc_point *q,
1338 const struct ecc_curve *curve)
1339{
1340 u64 z[ECC_MAX_DIGITS];
1341 u64 px[ECC_MAX_DIGITS];
1342 u64 py[ECC_MAX_DIGITS];
1343 unsigned int ndigits = curve->g.ndigits;
1344
1345 vli_set(result->x, q->x, ndigits);
1346 vli_set(result->y, q->y, ndigits);
1347 vli_mod_sub(z, result->x, p->x, curve->p, ndigits);
1348 vli_set(px, p->x, ndigits);
1349 vli_set(py, p->y, ndigits);
1350 xycz_add(px, py, result->x, result->y, curve);
1351 vli_mod_inv(z, z, curve->p, ndigits);
1352 apply_z(result->x, result->y, z, curve);
1353}
1354
1355
1356
1357
1358void ecc_point_mult_shamir(const struct ecc_point *result,
1359 const u64 *u1, const struct ecc_point *p,
1360 const u64 *u2, const struct ecc_point *q,
1361 const struct ecc_curve *curve)
1362{
1363 u64 z[ECC_MAX_DIGITS];
1364 u64 sump[2][ECC_MAX_DIGITS];
1365 u64 *rx = result->x;
1366 u64 *ry = result->y;
1367 unsigned int ndigits = curve->g.ndigits;
1368 unsigned int num_bits;
1369 struct ecc_point sum = ECC_POINT_INIT(sump[0], sump[1], ndigits);
1370 const struct ecc_point *points[4];
1371 const struct ecc_point *point;
1372 unsigned int idx;
1373 int i;
1374
1375 ecc_point_add(&sum, p, q, curve);
1376 points[0] = NULL;
1377 points[1] = p;
1378 points[2] = q;
1379 points[3] = ∑
1380
1381 num_bits = max(vli_num_bits(u1, ndigits), vli_num_bits(u2, ndigits));
1382 i = num_bits - 1;
1383 idx = (!!vli_test_bit(u1, i)) | ((!!vli_test_bit(u2, i)) << 1);
1384 point = points[idx];
1385
1386 vli_set(rx, point->x, ndigits);
1387 vli_set(ry, point->y, ndigits);
1388 vli_clear(z + 1, ndigits - 1);
1389 z[0] = 1;
1390
1391 for (--i; i >= 0; i--) {
1392 ecc_point_double_jacobian(rx, ry, z, curve);
1393 idx = (!!vli_test_bit(u1, i)) | ((!!vli_test_bit(u2, i)) << 1);
1394 point = points[idx];
1395 if (point) {
1396 u64 tx[ECC_MAX_DIGITS];
1397 u64 ty[ECC_MAX_DIGITS];
1398 u64 tz[ECC_MAX_DIGITS];
1399
1400 vli_set(tx, point->x, ndigits);
1401 vli_set(ty, point->y, ndigits);
1402 apply_z(tx, ty, z, curve);
1403 vli_mod_sub(tz, rx, tx, curve->p, ndigits);
1404 xycz_add(tx, ty, rx, ry, curve);
1405 vli_mod_mult_fast(z, z, tz, curve);
1406 }
1407 }
1408 vli_mod_inv(z, z, curve->p, ndigits);
1409 apply_z(rx, ry, z, curve);
1410}
1411EXPORT_SYMBOL(ecc_point_mult_shamir);
1412
1413static int __ecc_is_key_valid(const struct ecc_curve *curve,
1414 const u64 *private_key, unsigned int ndigits)
1415{
1416 u64 one[ECC_MAX_DIGITS] = { 1, };
1417 u64 res[ECC_MAX_DIGITS];
1418
1419 if (!private_key)
1420 return -EINVAL;
1421
1422 if (curve->g.ndigits != ndigits)
1423 return -EINVAL;
1424
1425
1426 if (vli_cmp(one, private_key, ndigits) != -1)
1427 return -EINVAL;
1428 vli_sub(res, curve->n, one, ndigits);
1429 vli_sub(res, res, one, ndigits);
1430 if (vli_cmp(res, private_key, ndigits) != 1)
1431 return -EINVAL;
1432
1433 return 0;
1434}
1435
1436int ecc_is_key_valid(unsigned int curve_id, unsigned int ndigits,
1437 const u64 *private_key, unsigned int private_key_len)
1438{
1439 int nbytes;
1440 const struct ecc_curve *curve = ecc_get_curve(curve_id);
1441
1442 nbytes = ndigits << ECC_DIGITS_TO_BYTES_SHIFT;
1443
1444 if (private_key_len != nbytes)
1445 return -EINVAL;
1446
1447 return __ecc_is_key_valid(curve, private_key, ndigits);
1448}
1449EXPORT_SYMBOL(ecc_is_key_valid);
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463int ecc_gen_privkey(unsigned int curve_id, unsigned int ndigits, u64 *privkey)
1464{
1465 const struct ecc_curve *curve = ecc_get_curve(curve_id);
1466 u64 priv[ECC_MAX_DIGITS];
1467 unsigned int nbytes = ndigits << ECC_DIGITS_TO_BYTES_SHIFT;
1468 unsigned int nbits = vli_num_bits(curve->n, ndigits);
1469 int err;
1470
1471
1472 if (nbits < 160 || ndigits > ARRAY_SIZE(priv))
1473 return -EINVAL;
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486 if (crypto_get_default_rng())
1487 return -EFAULT;
1488
1489 err = crypto_rng_get_bytes(crypto_default_rng, (u8 *)priv, nbytes);
1490 crypto_put_default_rng();
1491 if (err)
1492 return err;
1493
1494
1495 if (__ecc_is_key_valid(curve, priv, ndigits))
1496 return -EINVAL;
1497
1498 ecc_swap_digits(priv, privkey, ndigits);
1499
1500 return 0;
1501}
1502EXPORT_SYMBOL(ecc_gen_privkey);
1503
1504int ecc_make_pub_key(unsigned int curve_id, unsigned int ndigits,
1505 const u64 *private_key, u64 *public_key)
1506{
1507 int ret = 0;
1508 struct ecc_point *pk;
1509 u64 priv[ECC_MAX_DIGITS];
1510 const struct ecc_curve *curve = ecc_get_curve(curve_id);
1511
1512 if (!private_key || !curve || ndigits > ARRAY_SIZE(priv)) {
1513 ret = -EINVAL;
1514 goto out;
1515 }
1516
1517 ecc_swap_digits(private_key, priv, ndigits);
1518
1519 pk = ecc_alloc_point(ndigits);
1520 if (!pk) {
1521 ret = -ENOMEM;
1522 goto out;
1523 }
1524
1525 ecc_point_mult(pk, &curve->g, priv, NULL, curve, ndigits);
1526
1527
1528 if (ecc_is_pubkey_valid_full(curve, pk)) {
1529 ret = -EAGAIN;
1530 goto err_free_point;
1531 }
1532
1533 ecc_swap_digits(pk->x, public_key, ndigits);
1534 ecc_swap_digits(pk->y, &public_key[ndigits], ndigits);
1535
1536err_free_point:
1537 ecc_free_point(pk);
1538out:
1539 return ret;
1540}
1541EXPORT_SYMBOL(ecc_make_pub_key);
1542
1543
1544int ecc_is_pubkey_valid_partial(const struct ecc_curve *curve,
1545 struct ecc_point *pk)
1546{
1547 u64 yy[ECC_MAX_DIGITS], xxx[ECC_MAX_DIGITS], w[ECC_MAX_DIGITS];
1548
1549 if (WARN_ON(pk->ndigits != curve->g.ndigits))
1550 return -EINVAL;
1551
1552
1553 if (ecc_point_is_zero(pk))
1554 return -EINVAL;
1555
1556
1557 if (vli_cmp(curve->p, pk->x, pk->ndigits) != 1)
1558 return -EINVAL;
1559 if (vli_cmp(curve->p, pk->y, pk->ndigits) != 1)
1560 return -EINVAL;
1561
1562
1563 vli_mod_square_fast(yy, pk->y, curve);
1564 vli_mod_square_fast(xxx, pk->x, curve);
1565 vli_mod_mult_fast(xxx, xxx, pk->x, curve);
1566 vli_mod_mult_fast(w, curve->a, pk->x, curve);
1567 vli_mod_add(w, w, curve->b, curve->p, pk->ndigits);
1568 vli_mod_add(w, w, xxx, curve->p, pk->ndigits);
1569 if (vli_cmp(yy, w, pk->ndigits) != 0)
1570 return -EINVAL;
1571
1572 return 0;
1573}
1574EXPORT_SYMBOL(ecc_is_pubkey_valid_partial);
1575
1576
1577int ecc_is_pubkey_valid_full(const struct ecc_curve *curve,
1578 struct ecc_point *pk)
1579{
1580 struct ecc_point *nQ;
1581
1582
1583 int ret = ecc_is_pubkey_valid_partial(curve, pk);
1584
1585 if (ret)
1586 return ret;
1587
1588
1589 nQ = ecc_alloc_point(pk->ndigits);
1590 if (!nQ)
1591 return -ENOMEM;
1592
1593 ecc_point_mult(nQ, pk, curve->n, NULL, curve, pk->ndigits);
1594 if (!ecc_point_is_zero(nQ))
1595 ret = -EINVAL;
1596
1597 ecc_free_point(nQ);
1598
1599 return ret;
1600}
1601EXPORT_SYMBOL(ecc_is_pubkey_valid_full);
1602
1603int crypto_ecdh_shared_secret(unsigned int curve_id, unsigned int ndigits,
1604 const u64 *private_key, const u64 *public_key,
1605 u64 *secret)
1606{
1607 int ret = 0;
1608 struct ecc_point *product, *pk;
1609 u64 priv[ECC_MAX_DIGITS];
1610 u64 rand_z[ECC_MAX_DIGITS];
1611 unsigned int nbytes;
1612 const struct ecc_curve *curve = ecc_get_curve(curve_id);
1613
1614 if (!private_key || !public_key || !curve ||
1615 ndigits > ARRAY_SIZE(priv) || ndigits > ARRAY_SIZE(rand_z)) {
1616 ret = -EINVAL;
1617 goto out;
1618 }
1619
1620 nbytes = ndigits << ECC_DIGITS_TO_BYTES_SHIFT;
1621
1622 get_random_bytes(rand_z, nbytes);
1623
1624 pk = ecc_alloc_point(ndigits);
1625 if (!pk) {
1626 ret = -ENOMEM;
1627 goto out;
1628 }
1629
1630 ecc_swap_digits(public_key, pk->x, ndigits);
1631 ecc_swap_digits(&public_key[ndigits], pk->y, ndigits);
1632 ret = ecc_is_pubkey_valid_partial(curve, pk);
1633 if (ret)
1634 goto err_alloc_product;
1635
1636 ecc_swap_digits(private_key, priv, ndigits);
1637
1638 product = ecc_alloc_point(ndigits);
1639 if (!product) {
1640 ret = -ENOMEM;
1641 goto err_alloc_product;
1642 }
1643
1644 ecc_point_mult(product, pk, priv, rand_z, curve, ndigits);
1645
1646 if (ecc_point_is_zero(product)) {
1647 ret = -EFAULT;
1648 goto err_validity;
1649 }
1650
1651 ecc_swap_digits(product->x, secret, ndigits);
1652
1653err_validity:
1654 memzero_explicit(priv, sizeof(priv));
1655 memzero_explicit(rand_z, sizeof(rand_z));
1656 ecc_free_point(product);
1657err_alloc_product:
1658 ecc_free_point(pk);
1659out:
1660 return ret;
1661}
1662EXPORT_SYMBOL(crypto_ecdh_shared_secret);
1663
1664MODULE_LICENSE("Dual BSD/GPL");
1665