+++ /dev/null
-/*
- * Copyright (c) 2013, Kenneth MacKay
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
- * * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- * * Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in the
- * documentation and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
-
-#include <linux/random.h>
-
-#include "ecc.h"
-
-/* 256-bit curve */
-#define ECC_BYTES 32
-
-#define MAX_TRIES 16
-
-/* Number of u64's needed */
-#define NUM_ECC_DIGITS (ECC_BYTES / 8)
-
-struct ecc_point {
- u64 x[NUM_ECC_DIGITS];
- u64 y[NUM_ECC_DIGITS];
-};
-
-typedef struct {
- u64 m_low;
- u64 m_high;
-} uint128_t;
-
-#define CURVE_P_32 { 0xFFFFFFFFFFFFFFFFull, 0x00000000FFFFFFFFull, \
- 0x0000000000000000ull, 0xFFFFFFFF00000001ull }
-
-#define CURVE_G_32 { \
- { 0xF4A13945D898C296ull, 0x77037D812DEB33A0ull, \
- 0xF8BCE6E563A440F2ull, 0x6B17D1F2E12C4247ull }, \
- { 0xCBB6406837BF51F5ull, 0x2BCE33576B315ECEull, \
- 0x8EE7EB4A7C0F9E16ull, 0x4FE342E2FE1A7F9Bull } \
-}
-
-#define CURVE_N_32 { 0xF3B9CAC2FC632551ull, 0xBCE6FAADA7179E84ull, \
- 0xFFFFFFFFFFFFFFFFull, 0xFFFFFFFF00000000ull }
-
-static u64 curve_p[NUM_ECC_DIGITS] = CURVE_P_32;
-static struct ecc_point curve_g = CURVE_G_32;
-static u64 curve_n[NUM_ECC_DIGITS] = CURVE_N_32;
-
-static void vli_clear(u64 *vli)
-{
- int i;
-
- for (i = 0; i < NUM_ECC_DIGITS; i++)
- vli[i] = 0;
-}
-
-/* Returns true if vli == 0, false otherwise. */
-static bool vli_is_zero(const u64 *vli)
-{
- int i;
-
- for (i = 0; i < NUM_ECC_DIGITS; i++) {
- if (vli[i])
- return false;
- }
-
- return true;
-}
-
-/* Returns nonzero if bit bit of vli is set. */
-static u64 vli_test_bit(const u64 *vli, unsigned int bit)
-{
- return (vli[bit / 64] & ((u64) 1 << (bit % 64)));
-}
-
-/* Counts the number of 64-bit "digits" in vli. */
-static unsigned int vli_num_digits(const u64 *vli)
-{
- int i;
-
- /* Search from the end until we find a non-zero digit.
- * We do it in reverse because we expect that most digits will
- * be nonzero.
- */
- for (i = NUM_ECC_DIGITS - 1; i >= 0 && vli[i] == 0; i--);
-
- return (i + 1);
-}
-
-/* Counts the number of bits required for vli. */
-static unsigned int vli_num_bits(const u64 *vli)
-{
- unsigned int i, num_digits;
- u64 digit;
-
- num_digits = vli_num_digits(vli);
- if (num_digits == 0)
- return 0;
-
- digit = vli[num_digits - 1];
- for (i = 0; digit; i++)
- digit >>= 1;
-
- return ((num_digits - 1) * 64 + i);
-}
-
-/* Sets dest = src. */
-static void vli_set(u64 *dest, const u64 *src)
-{
- int i;
-
- for (i = 0; i < NUM_ECC_DIGITS; i++)
- dest[i] = src[i];
-}
-
-/* Returns sign of left - right. */
-static int vli_cmp(const u64 *left, const u64 *right)
-{
- int i;
-
- for (i = NUM_ECC_DIGITS - 1; i >= 0; i--) {
- if (left[i] > right[i])
- return 1;
- else if (left[i] < right[i])
- return -1;
- }
-
- return 0;
-}
-
-/* Computes result = in << c, returning carry. Can modify in place
- * (if result == in). 0 < shift < 64.
- */
-static u64 vli_lshift(u64 *result, const u64 *in,
- unsigned int shift)
-{
- u64 carry = 0;
- int i;
-
- for (i = 0; i < NUM_ECC_DIGITS; i++) {
- u64 temp = in[i];
-
- result[i] = (temp << shift) | carry;
- carry = temp >> (64 - shift);
- }
-
- return carry;
-}
-
-/* Computes vli = vli >> 1. */
-static void vli_rshift1(u64 *vli)
-{
- u64 *end = vli;
- u64 carry = 0;
-
- vli += NUM_ECC_DIGITS;
-
- while (vli-- > end) {
- u64 temp = *vli;
- *vli = (temp >> 1) | carry;
- carry = temp << 63;
- }
-}
-
-/* Computes result = left + right, returning carry. Can modify in place. */
-static u64 vli_add(u64 *result, const u64 *left,
- const u64 *right)
-{
- u64 carry = 0;
- int i;
-
- for (i = 0; i < NUM_ECC_DIGITS; i++) {
- u64 sum;
-
- sum = left[i] + right[i] + carry;
- if (sum != left[i])
- carry = (sum < left[i]);
-
- result[i] = sum;
- }
-
- return carry;
-}
-
-/* Computes result = left - right, returning borrow. Can modify in place. */
-static u64 vli_sub(u64 *result, const u64 *left, const u64 *right)
-{
- u64 borrow = 0;
- int i;
-
- for (i = 0; i < NUM_ECC_DIGITS; i++) {
- u64 diff;
-
- diff = left[i] - right[i] - borrow;
- if (diff != left[i])
- borrow = (diff > left[i]);
-
- result[i] = diff;
- }
-
- return borrow;
-}
-
-static uint128_t mul_64_64(u64 left, u64 right)
-{
- u64 a0 = left & 0xffffffffull;
- u64 a1 = left >> 32;
- u64 b0 = right & 0xffffffffull;
- u64 b1 = right >> 32;
- u64 m0 = a0 * b0;
- u64 m1 = a0 * b1;
- u64 m2 = a1 * b0;
- u64 m3 = a1 * b1;
- uint128_t result;
-
- m2 += (m0 >> 32);
- m2 += m1;
-
- /* Overflow */
- if (m2 < m1)
- m3 += 0x100000000ull;
-
- result.m_low = (m0 & 0xffffffffull) | (m2 << 32);
- result.m_high = m3 + (m2 >> 32);
-
- return result;
-}
-
-static uint128_t add_128_128(uint128_t a, uint128_t b)
-{
- uint128_t result;
-
- result.m_low = a.m_low + b.m_low;
- result.m_high = a.m_high + b.m_high + (result.m_low < a.m_low);
-
- return result;
-}
-
-static void vli_mult(u64 *result, const u64 *left, const u64 *right)
-{
- uint128_t r01 = { 0, 0 };
- u64 r2 = 0;
- unsigned int i, k;
-
- /* Compute each digit of result in sequence, maintaining the
- * carries.
- */
- for (k = 0; k < NUM_ECC_DIGITS * 2 - 1; k++) {
- unsigned int min;
-
- if (k < NUM_ECC_DIGITS)
- min = 0;
- else
- min = (k + 1) - NUM_ECC_DIGITS;
-
- for (i = min; i <= k && i < NUM_ECC_DIGITS; i++) {
- uint128_t product;
-
- product = mul_64_64(left[i], right[k - i]);
-
- r01 = add_128_128(r01, product);
- r2 += (r01.m_high < product.m_high);
- }
-
- result[k] = r01.m_low;
- r01.m_low = r01.m_high;
- r01.m_high = r2;
- r2 = 0;
- }
-
- result[NUM_ECC_DIGITS * 2 - 1] = r01.m_low;
-}
-
-static void vli_square(u64 *result, const u64 *left)
-{
- uint128_t r01 = { 0, 0 };
- u64 r2 = 0;
- int i, k;
-
- for (k = 0; k < NUM_ECC_DIGITS * 2 - 1; k++) {
- unsigned int min;
-
- if (k < NUM_ECC_DIGITS)
- min = 0;
- else
- min = (k + 1) - NUM_ECC_DIGITS;
-
- for (i = min; i <= k && i <= k - i; i++) {
- uint128_t product;
-
- product = mul_64_64(left[i], left[k - i]);
-
- if (i < k - i) {
- r2 += product.m_high >> 63;
- product.m_high = (product.m_high << 1) |
- (product.m_low >> 63);
- product.m_low <<= 1;
- }
-
- r01 = add_128_128(r01, product);
- r2 += (r01.m_high < product.m_high);
- }
-
- result[k] = r01.m_low;
- r01.m_low = r01.m_high;
- r01.m_high = r2;
- r2 = 0;
- }
-
- result[NUM_ECC_DIGITS * 2 - 1] = r01.m_low;
-}
-
-/* Computes result = (left + right) % mod.
- * Assumes that left < mod and right < mod, result != mod.
- */
-static void vli_mod_add(u64 *result, const u64 *left, const u64 *right,
- const u64 *mod)
-{
- u64 carry;
-
- carry = vli_add(result, left, right);
-
- /* result > mod (result = mod + remainder), so subtract mod to
- * get remainder.
- */
- if (carry || vli_cmp(result, mod) >= 0)
- vli_sub(result, result, mod);
-}
-
-/* Computes result = (left - right) % mod.
- * Assumes that left < mod and right < mod, result != mod.
- */
-static void vli_mod_sub(u64 *result, const u64 *left, const u64 *right,
- const u64 *mod)
-{
- u64 borrow = vli_sub(result, left, right);
-
- /* In this case, p_result == -diff == (max int) - diff.
- * Since -x % d == d - x, we can get the correct result from
- * result + mod (with overflow).
- */
- if (borrow)
- vli_add(result, result, mod);
-}
-
-/* Computes result = product % curve_p
- from http://www.nsa.gov/ia/_files/nist-routines.pdf */
-static void vli_mmod_fast(u64 *result, const u64 *product)
-{
- u64 tmp[NUM_ECC_DIGITS];
- int carry;
-
- /* t */
- vli_set(result, product);
-
- /* s1 */
- tmp[0] = 0;
- tmp[1] = product[5] & 0xffffffff00000000ull;
- tmp[2] = product[6];
- tmp[3] = product[7];
- carry = vli_lshift(tmp, tmp, 1);
- carry += vli_add(result, result, tmp);
-
- /* s2 */
- tmp[1] = product[6] << 32;
- tmp[2] = (product[6] >> 32) | (product[7] << 32);
- tmp[3] = product[7] >> 32;
- carry += vli_lshift(tmp, tmp, 1);
- carry += vli_add(result, result, tmp);
-
- /* s3 */
- tmp[0] = product[4];
- tmp[1] = product[5] & 0xffffffff;
- tmp[2] = 0;
- tmp[3] = product[7];
- carry += vli_add(result, result, tmp);
-
- /* s4 */
- tmp[0] = (product[4] >> 32) | (product[5] << 32);
- tmp[1] = (product[5] >> 32) | (product[6] & 0xffffffff00000000ull);
- tmp[2] = product[7];
- tmp[3] = (product[6] >> 32) | (product[4] << 32);
- carry += vli_add(result, result, tmp);
-
- /* d1 */
- tmp[0] = (product[5] >> 32) | (product[6] << 32);
- tmp[1] = (product[6] >> 32);
- tmp[2] = 0;
- tmp[3] = (product[4] & 0xffffffff) | (product[5] << 32);
- carry -= vli_sub(result, result, tmp);
-
- /* d2 */
- tmp[0] = product[6];
- tmp[1] = product[7];
- tmp[2] = 0;
- tmp[3] = (product[4] >> 32) | (product[5] & 0xffffffff00000000ull);
- carry -= vli_sub(result, result, tmp);
-
- /* d3 */
- tmp[0] = (product[6] >> 32) | (product[7] << 32);
- tmp[1] = (product[7] >> 32) | (product[4] << 32);
- tmp[2] = (product[4] >> 32) | (product[5] << 32);
- tmp[3] = (product[6] << 32);
- carry -= vli_sub(result, result, tmp);
-
- /* d4 */
- tmp[0] = product[7];
- tmp[1] = product[4] & 0xffffffff00000000ull;
- tmp[2] = product[5];
- tmp[3] = product[6] & 0xffffffff00000000ull;
- carry -= vli_sub(result, result, tmp);
-
- if (carry < 0) {
- do {
- carry += vli_add(result, result, curve_p);
- } while (carry < 0);
- } else {
- while (carry || vli_cmp(curve_p, result) != 1)
- carry -= vli_sub(result, result, curve_p);
- }
-}
-
-/* Computes result = (left * right) % curve_p. */
-static void vli_mod_mult_fast(u64 *result, const u64 *left, const u64 *right)
-{
- u64 product[2 * NUM_ECC_DIGITS];
-
- vli_mult(product, left, right);
- vli_mmod_fast(result, product);
-}
-
-/* Computes result = left^2 % curve_p. */
-static void vli_mod_square_fast(u64 *result, const u64 *left)
-{
- u64 product[2 * NUM_ECC_DIGITS];
-
- vli_square(product, left);
- vli_mmod_fast(result, product);
-}
-
-#define EVEN(vli) (!(vli[0] & 1))
-/* Computes result = (1 / p_input) % mod. All VLIs are the same size.
- * See "From Euclid's GCD to Montgomery Multiplication to the Great Divide"
- * https://labs.oracle.com/techrep/2001/smli_tr-2001-95.pdf
- */
-static void vli_mod_inv(u64 *result, const u64 *input, const u64 *mod)
-{
- u64 a[NUM_ECC_DIGITS], b[NUM_ECC_DIGITS];
- u64 u[NUM_ECC_DIGITS], v[NUM_ECC_DIGITS];
- u64 carry;
- int cmp_result;
-
- if (vli_is_zero(input)) {
- vli_clear(result);
- return;
- }
-
- vli_set(a, input);
- vli_set(b, mod);
- vli_clear(u);
- u[0] = 1;
- vli_clear(v);
-
- while ((cmp_result = vli_cmp(a, b)) != 0) {
- carry = 0;
-
- if (EVEN(a)) {
- vli_rshift1(a);
-
- if (!EVEN(u))
- carry = vli_add(u, u, mod);
-
- vli_rshift1(u);
- if (carry)
- u[NUM_ECC_DIGITS - 1] |= 0x8000000000000000ull;
- } else if (EVEN(b)) {
- vli_rshift1(b);
-
- if (!EVEN(v))
- carry = vli_add(v, v, mod);
-
- vli_rshift1(v);
- if (carry)
- v[NUM_ECC_DIGITS - 1] |= 0x8000000000000000ull;
- } else if (cmp_result > 0) {
- vli_sub(a, a, b);
- vli_rshift1(a);
-
- if (vli_cmp(u, v) < 0)
- vli_add(u, u, mod);
-
- vli_sub(u, u, v);
- if (!EVEN(u))
- carry = vli_add(u, u, mod);
-
- vli_rshift1(u);
- if (carry)
- u[NUM_ECC_DIGITS - 1] |= 0x8000000000000000ull;
- } else {
- vli_sub(b, b, a);
- vli_rshift1(b);
-
- if (vli_cmp(v, u) < 0)
- vli_add(v, v, mod);
-
- vli_sub(v, v, u);
- if (!EVEN(v))
- carry = vli_add(v, v, mod);
-
- vli_rshift1(v);
- if (carry)
- v[NUM_ECC_DIGITS - 1] |= 0x8000000000000000ull;
- }
- }
-
- vli_set(result, u);
-}
-
-/* ------ Point operations ------ */
-
-/* Returns true if p_point is the point at infinity, false otherwise. */
-static bool ecc_point_is_zero(const struct ecc_point *point)
-{
- return (vli_is_zero(point->x) && vli_is_zero(point->y));
-}
-
-/* Point multiplication algorithm using Montgomery's ladder with co-Z
- * coordinates. From http://eprint.iacr.org/2011/338.pdf
- */
-
-/* Double in place */
-static void ecc_point_double_jacobian(u64 *x1, u64 *y1, u64 *z1)
-{
- /* t1 = x, t2 = y, t3 = z */
- u64 t4[NUM_ECC_DIGITS];
- u64 t5[NUM_ECC_DIGITS];
-
- if (vli_is_zero(z1))
- return;
-
- vli_mod_square_fast(t4, y1); /* t4 = y1^2 */
- vli_mod_mult_fast(t5, x1, t4); /* t5 = x1*y1^2 = A */
- vli_mod_square_fast(t4, t4); /* t4 = y1^4 */
- vli_mod_mult_fast(y1, y1, z1); /* t2 = y1*z1 = z3 */
- vli_mod_square_fast(z1, z1); /* t3 = z1^2 */
-
- vli_mod_add(x1, x1, z1, curve_p); /* t1 = x1 + z1^2 */
- vli_mod_add(z1, z1, z1, curve_p); /* t3 = 2*z1^2 */
- vli_mod_sub(z1, x1, z1, curve_p); /* t3 = x1 - z1^2 */
- vli_mod_mult_fast(x1, x1, z1); /* t1 = x1^2 - z1^4 */
-
- vli_mod_add(z1, x1, x1, curve_p); /* t3 = 2*(x1^2 - z1^4) */
- vli_mod_add(x1, x1, z1, curve_p); /* t1 = 3*(x1^2 - z1^4) */
- if (vli_test_bit(x1, 0)) {
- u64 carry = vli_add(x1, x1, curve_p);
- vli_rshift1(x1);
- x1[NUM_ECC_DIGITS - 1] |= carry << 63;
- } else {
- vli_rshift1(x1);
- }
- /* t1 = 3/2*(x1^2 - z1^4) = B */
-
- vli_mod_square_fast(z1, x1); /* t3 = B^2 */
- vli_mod_sub(z1, z1, t5, curve_p); /* t3 = B^2 - A */
- vli_mod_sub(z1, z1, t5, curve_p); /* t3 = B^2 - 2A = x3 */
- vli_mod_sub(t5, t5, z1, curve_p); /* t5 = A - x3 */
- vli_mod_mult_fast(x1, x1, t5); /* t1 = B * (A - x3) */
- vli_mod_sub(t4, x1, t4, curve_p); /* t4 = B * (A - x3) - y1^4 = y3 */
-
- vli_set(x1, z1);
- vli_set(z1, y1);
- vli_set(y1, t4);
-}
-
-/* Modify (x1, y1) => (x1 * z^2, y1 * z^3) */
-static void apply_z(u64 *x1, u64 *y1, u64 *z)
-{
- u64 t1[NUM_ECC_DIGITS];
-
- vli_mod_square_fast(t1, z); /* z^2 */
- vli_mod_mult_fast(x1, x1, t1); /* x1 * z^2 */
- vli_mod_mult_fast(t1, t1, z); /* z^3 */
- vli_mod_mult_fast(y1, y1, t1); /* y1 * z^3 */
-}
-
-/* P = (x1, y1) => 2P, (x2, y2) => P' */
-static void xycz_initial_double(u64 *x1, u64 *y1, u64 *x2, u64 *y2,
- u64 *p_initial_z)
-{
- u64 z[NUM_ECC_DIGITS];
-
- vli_set(x2, x1);
- vli_set(y2, y1);
-
- vli_clear(z);
- z[0] = 1;
-
- if (p_initial_z)
- vli_set(z, p_initial_z);
-
- apply_z(x1, y1, z);
-
- ecc_point_double_jacobian(x1, y1, z);
-
- apply_z(x2, y2, z);
-}
-
-/* Input P = (x1, y1, Z), Q = (x2, y2, Z)
- * Output P' = (x1', y1', Z3), P + Q = (x3, y3, Z3)
- * or P => P', Q => P + Q
- */
-static void xycz_add(u64 *x1, u64 *y1, u64 *x2, u64 *y2)
-{
- /* t1 = X1, t2 = Y1, t3 = X2, t4 = Y2 */
- u64 t5[NUM_ECC_DIGITS];
-
- vli_mod_sub(t5, x2, x1, curve_p); /* t5 = x2 - x1 */
- vli_mod_square_fast(t5, t5); /* t5 = (x2 - x1)^2 = A */
- vli_mod_mult_fast(x1, x1, t5); /* t1 = x1*A = B */
- vli_mod_mult_fast(x2, x2, t5); /* t3 = x2*A = C */
- vli_mod_sub(y2, y2, y1, curve_p); /* t4 = y2 - y1 */
- vli_mod_square_fast(t5, y2); /* t5 = (y2 - y1)^2 = D */
-
- vli_mod_sub(t5, t5, x1, curve_p); /* t5 = D - B */
- vli_mod_sub(t5, t5, x2, curve_p); /* t5 = D - B - C = x3 */
- vli_mod_sub(x2, x2, x1, curve_p); /* t3 = C - B */
- vli_mod_mult_fast(y1, y1, x2); /* t2 = y1*(C - B) */
- vli_mod_sub(x2, x1, t5, curve_p); /* t3 = B - x3 */
- vli_mod_mult_fast(y2, y2, x2); /* t4 = (y2 - y1)*(B - x3) */
- vli_mod_sub(y2, y2, y1, curve_p); /* t4 = y3 */
-
- vli_set(x2, t5);
-}
-
-/* Input P = (x1, y1, Z), Q = (x2, y2, Z)
- * Output P + Q = (x3, y3, Z3), P - Q = (x3', y3', Z3)
- * or P => P - Q, Q => P + Q
- */
-static void xycz_add_c(u64 *x1, u64 *y1, u64 *x2, u64 *y2)
-{
- /* t1 = X1, t2 = Y1, t3 = X2, t4 = Y2 */
- u64 t5[NUM_ECC_DIGITS];
- u64 t6[NUM_ECC_DIGITS];
- u64 t7[NUM_ECC_DIGITS];
-
- vli_mod_sub(t5, x2, x1, curve_p); /* t5 = x2 - x1 */
- vli_mod_square_fast(t5, t5); /* t5 = (x2 - x1)^2 = A */
- vli_mod_mult_fast(x1, x1, t5); /* t1 = x1*A = B */
- vli_mod_mult_fast(x2, x2, t5); /* t3 = x2*A = C */
- vli_mod_add(t5, y2, y1, curve_p); /* t4 = y2 + y1 */
- vli_mod_sub(y2, y2, y1, curve_p); /* t4 = y2 - y1 */
-
- vli_mod_sub(t6, x2, x1, curve_p); /* t6 = C - B */
- vli_mod_mult_fast(y1, y1, t6); /* t2 = y1 * (C - B) */
- vli_mod_add(t6, x1, x2, curve_p); /* t6 = B + C */
- vli_mod_square_fast(x2, y2); /* t3 = (y2 - y1)^2 */
- vli_mod_sub(x2, x2, t6, curve_p); /* t3 = x3 */
-
- vli_mod_sub(t7, x1, x2, curve_p); /* t7 = B - x3 */
- vli_mod_mult_fast(y2, y2, t7); /* t4 = (y2 - y1)*(B - x3) */
- vli_mod_sub(y2, y2, y1, curve_p); /* t4 = y3 */
-
- vli_mod_square_fast(t7, t5); /* t7 = (y2 + y1)^2 = F */
- vli_mod_sub(t7, t7, t6, curve_p); /* t7 = x3' */
- vli_mod_sub(t6, t7, x1, curve_p); /* t6 = x3' - B */
- vli_mod_mult_fast(t6, t6, t5); /* t6 = (y2 + y1)*(x3' - B) */
- vli_mod_sub(y1, t6, y1, curve_p); /* t2 = y3' */
-
- vli_set(x1, t7);
-}
-
-static void ecc_point_mult(struct ecc_point *result,
- const struct ecc_point *point, u64 *scalar,
- u64 *initial_z, int num_bits)
-{
- /* R0 and R1 */
- u64 rx[2][NUM_ECC_DIGITS];
- u64 ry[2][NUM_ECC_DIGITS];
- u64 z[NUM_ECC_DIGITS];
- int i, nb;
-
- vli_set(rx[1], point->x);
- vli_set(ry[1], point->y);
-
- xycz_initial_double(rx[1], ry[1], rx[0], ry[0], initial_z);
-
- for (i = num_bits - 2; i > 0; i--) {
- nb = !vli_test_bit(scalar, i);
- xycz_add_c(rx[1 - nb], ry[1 - nb], rx[nb], ry[nb]);
- xycz_add(rx[nb], ry[nb], rx[1 - nb], ry[1 - nb]);
- }
-
- nb = !vli_test_bit(scalar, 0);
- xycz_add_c(rx[1 - nb], ry[1 - nb], rx[nb], ry[nb]);
-
- /* Find final 1/Z value. */
- vli_mod_sub(z, rx[1], rx[0], curve_p); /* X1 - X0 */
- vli_mod_mult_fast(z, z, ry[1 - nb]); /* Yb * (X1 - X0) */
- vli_mod_mult_fast(z, z, point->x); /* xP * Yb * (X1 - X0) */
- vli_mod_inv(z, z, curve_p); /* 1 / (xP * Yb * (X1 - X0)) */
- vli_mod_mult_fast(z, z, point->y); /* yP / (xP * Yb * (X1 - X0)) */
- vli_mod_mult_fast(z, z, rx[1 - nb]); /* Xb * yP / (xP * Yb * (X1 - X0)) */
- /* End 1/Z calculation */
-
- xycz_add(rx[nb], ry[nb], rx[1 - nb], ry[1 - nb]);
-
- apply_z(rx[0], ry[0], z);
-
- vli_set(result->x, rx[0]);
- vli_set(result->y, ry[0]);
-}
-
-static void ecc_bytes2native(const u8 bytes[ECC_BYTES],
- u64 native[NUM_ECC_DIGITS])
-{
- int i;
-
- for (i = 0; i < NUM_ECC_DIGITS; i++) {
- const u8 *digit = bytes + 8 * (NUM_ECC_DIGITS - 1 - i);
-
- native[NUM_ECC_DIGITS - 1 - i] =
- ((u64) digit[0] << 0) |
- ((u64) digit[1] << 8) |
- ((u64) digit[2] << 16) |
- ((u64) digit[3] << 24) |
- ((u64) digit[4] << 32) |
- ((u64) digit[5] << 40) |
- ((u64) digit[6] << 48) |
- ((u64) digit[7] << 56);
- }
-}
-
-static void ecc_native2bytes(const u64 native[NUM_ECC_DIGITS],
- u8 bytes[ECC_BYTES])
-{
- int i;
-
- for (i = 0; i < NUM_ECC_DIGITS; i++) {
- u8 *digit = bytes + 8 * (NUM_ECC_DIGITS - 1 - i);
-
- digit[0] = native[NUM_ECC_DIGITS - 1 - i] >> 0;
- digit[1] = native[NUM_ECC_DIGITS - 1 - i] >> 8;
- digit[2] = native[NUM_ECC_DIGITS - 1 - i] >> 16;
- digit[3] = native[NUM_ECC_DIGITS - 1 - i] >> 24;
- digit[4] = native[NUM_ECC_DIGITS - 1 - i] >> 32;
- digit[5] = native[NUM_ECC_DIGITS - 1 - i] >> 40;
- digit[6] = native[NUM_ECC_DIGITS - 1 - i] >> 48;
- digit[7] = native[NUM_ECC_DIGITS - 1 - i] >> 56;
- }
-}
-
-bool ecc_make_key(u8 public_key[64], u8 private_key[32])
-{
- struct ecc_point pk;
- u64 priv[NUM_ECC_DIGITS];
- unsigned int tries = 0;
-
- do {
- if (tries++ >= MAX_TRIES)
- return false;
-
- get_random_bytes(priv, ECC_BYTES);
-
- if (vli_is_zero(priv))
- continue;
-
- /* Make sure the private key is in the range [1, n-1]. */
- if (vli_cmp(curve_n, priv) != 1)
- continue;
-
- ecc_point_mult(&pk, &curve_g, priv, NULL, vli_num_bits(priv));
- } while (ecc_point_is_zero(&pk));
-
- ecc_native2bytes(priv, private_key);
- ecc_native2bytes(pk.x, public_key);
- ecc_native2bytes(pk.y, &public_key[32]);
-
- return true;
-}
-
-bool ecdh_shared_secret(const u8 public_key[64], const u8 private_key[32],
- u8 secret[32])
-{
- u64 priv[NUM_ECC_DIGITS];
- u64 rand[NUM_ECC_DIGITS];
- struct ecc_point product, pk;
-
- get_random_bytes(rand, ECC_BYTES);
-
- ecc_bytes2native(public_key, pk.x);
- ecc_bytes2native(&public_key[32], pk.y);
- ecc_bytes2native(private_key, priv);
-
- ecc_point_mult(&product, &pk, priv, rand, vli_num_bits(priv));
-
- ecc_native2bytes(product.x, secret);
-
- return !ecc_point_is_zero(&product);
-}
--- /dev/null
+/*
+ * ECDH helper functions - KPP wrappings
+ *
+ * Copyright (C) 2017 Intel Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation;
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF THIRD PARTY RIGHTS.
+ * IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) AND AUTHOR(S) BE LIABLE FOR ANY
+ * CLAIM, OR ANY SPECIAL INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ * ALL LIABILITY, INCLUDING LIABILITY FOR INFRINGEMENT OF ANY PATENTS,
+ * COPYRIGHTS, TRADEMARKS OR OTHER RIGHTS, RELATING TO USE OF THIS
+ * SOFTWARE IS DISCLAIMED.
+ */
+#include "ecdh_helper.h"
+
+#include <linux/random.h>
+#include <linux/scatterlist.h>
+#include <crypto/kpp.h>
+#include <crypto/ecdh.h>
+
+struct ecdh_completion {
+ struct completion completion;
+ int err;
+};
+
+static void ecdh_complete(struct crypto_async_request *req, int err)
+{
+ struct ecdh_completion *res = req->data;
+
+ if (err == -EINPROGRESS)
+ return;
+
+ res->err = err;
+ complete(&res->completion);
+}
+
+static inline void swap_digits(u64 *in, u64 *out, unsigned int ndigits)
+{
+ int i;
+
+ for (i = 0; i < ndigits; i++)
+ out[i] = __swab64(in[ndigits - 1 - i]);
+}
+
+bool compute_ecdh_secret(const u8 public_key[64], const u8 private_key[32],
+ u8 secret[32])
+{
+ struct crypto_kpp *tfm;
+ struct kpp_request *req;
+ struct ecdh p;
+ struct ecdh_completion result;
+ struct scatterlist src, dst;
+ u8 tmp[64];
+ u8 *buf;
+ unsigned int buf_len;
+ int err = -ENOMEM;
+
+ tfm = crypto_alloc_kpp("ecdh", CRYPTO_ALG_INTERNAL, 0);
+ if (IS_ERR(tfm)) {
+ pr_err("alg: kpp: Failed to load tfm for kpp: %ld\n",
+ PTR_ERR(tfm));
+ return false;
+ }
+
+ req = kpp_request_alloc(tfm, GFP_KERNEL);
+ if (!req)
+ goto free_kpp;
+
+ init_completion(&result.completion);
+
+ /* Security Manager Protocol holds digits in litte-endian order
+ * while ECC API expect big-endian data
+ */
+ swap_digits((u64 *)private_key, (u64 *)tmp, 4);
+ p.key = (char *)tmp;
+ p.key_size = 32;
+ /* Set curve_id */
+ p.curve_id = ECC_CURVE_NIST_P256;
+ buf_len = crypto_ecdh_key_len(&p);
+ buf = kmalloc(buf_len, GFP_KERNEL);
+ if (!buf) {
+ pr_err("alg: kpp: Failed to allocate %d bytes for buf\n",
+ buf_len);
+ goto free_req;
+ }
+ crypto_ecdh_encode_key(buf, buf_len, &p);
+
+ /* Set A private Key */
+ err = crypto_kpp_set_secret(tfm, (void *)buf, buf_len);
+ if (err)
+ goto free_all;
+
+ swap_digits((u64 *)public_key, (u64 *)tmp, 4); /* x */
+ swap_digits((u64 *)&public_key[32], (u64 *)&tmp[32], 4); /* y */
+
+ sg_init_one(&src, tmp, 64);
+ sg_init_one(&dst, secret, 32);
+ kpp_request_set_input(req, &src, 64);
+ kpp_request_set_output(req, &dst, 32);
+ kpp_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
+ ecdh_complete, &result);
+ err = crypto_kpp_compute_shared_secret(req);
+ if (err == -EINPROGRESS) {
+ wait_for_completion(&result.completion);
+ err = result.err;
+ }
+ if (err < 0) {
+ pr_err("alg: ecdh: compute shared secret failed. err %d\n",
+ err);
+ goto free_all;
+ }
+
+ swap_digits((u64 *)secret, (u64 *)tmp, 4);
+ memcpy(secret, tmp, 32);
+
+free_all:
+ kzfree(buf);
+free_req:
+ kpp_request_free(req);
+free_kpp:
+ crypto_free_kpp(tfm);
+ return (err == 0);
+}
+
+bool generate_ecdh_keys(u8 public_key[64], u8 private_key[32])
+{
+ struct crypto_kpp *tfm;
+ struct kpp_request *req;
+ struct ecdh p;
+ struct ecdh_completion result;
+ struct scatterlist dst;
+ u8 tmp[64];
+ u8 *buf;
+ unsigned int buf_len;
+ int err = -ENOMEM;
+ const unsigned short max_tries = 16;
+ unsigned short tries = 0;
+
+ tfm = crypto_alloc_kpp("ecdh", CRYPTO_ALG_INTERNAL, 0);
+ if (IS_ERR(tfm)) {
+ pr_err("alg: kpp: Failed to load tfm for kpp: %ld\n",
+ PTR_ERR(tfm));
+ return false;
+ }
+
+ req = kpp_request_alloc(tfm, GFP_KERNEL);
+ if (!req)
+ goto free_kpp;
+
+ init_completion(&result.completion);
+
+ /* Set curve_id */
+ p.curve_id = ECC_CURVE_NIST_P256;
+ p.key_size = 32;
+ buf_len = crypto_ecdh_key_len(&p);
+ buf = kmalloc(buf_len, GFP_KERNEL);
+ if (!buf) {
+ pr_err("alg: kpp: Failed to allocate %d bytes for buf\n",
+ buf_len);
+ goto free_req;
+ }
+
+ do {
+ if (tries++ >= max_tries)
+ goto free_all;
+
+ get_random_bytes(private_key, 32);
+
+ /* Set private Key */
+ p.key = (char *)private_key;
+ crypto_ecdh_encode_key(buf, buf_len, &p);
+ err = crypto_kpp_set_secret(tfm, buf, buf_len);
+ if (err)
+ goto free_all;
+
+ sg_init_one(&dst, tmp, 64);
+ kpp_request_set_output(req, &dst, 64);
+ kpp_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
+ ecdh_complete, &result);
+
+ err = crypto_kpp_generate_public_key(req);
+
+ if (err == -EINPROGRESS) {
+ wait_for_completion(&result.completion);
+ err = result.err;
+ }
+
+ /* Private key is not valid. Regenerate */
+ if (err == -EINVAL)
+ continue;
+
+ if (err < 0)
+ goto free_all;
+ else
+ break;
+
+ } while (true);
+
+ /* Keys are handed back in little endian as expected by Security
+ * Manager Protocol
+ */
+ swap_digits((u64 *)tmp, (u64 *)public_key, 4); /* x */
+ swap_digits((u64 *)&tmp[32], (u64 *)&public_key[32], 4); /* y */
+ swap_digits((u64 *)private_key, (u64 *)tmp, 4);
+ memcpy(private_key, tmp, 32);
+
+free_all:
+ kzfree(buf);
+free_req:
+ kpp_request_free(req);
+free_kpp:
+ crypto_free_kpp(tfm);
+ return (err == 0);
+}
projects / openwrt / staging / blogic.git / commitdiff