From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- crypto/ecc.c | 1668 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 1668 insertions(+) create mode 100644 crypto/ecc.c (limited to 'crypto/ecc.c') diff --git a/crypto/ecc.c b/crypto/ecc.c new file mode 100644 index 000000000..7315217c8 --- /dev/null +++ b/crypto/ecc.c @@ -0,0 +1,1668 @@ +/* + * Copyright (c) 2013, 2014 Kenneth MacKay. All rights reserved. + * Copyright (c) 2019 Vitaly Chikunov + * + * 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 +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "ecc_curve_defs.h" + +typedef struct { + u64 m_low; + u64 m_high; +} uint128_t; + +/* Returns curv25519 curve param */ +const struct ecc_curve *ecc_get_curve25519(void) +{ + return &ecc_25519; +} +EXPORT_SYMBOL(ecc_get_curve25519); + +const struct ecc_curve *ecc_get_curve(unsigned int curve_id) +{ + switch (curve_id) { + /* In FIPS mode only allow P256 and higher */ + case ECC_CURVE_NIST_P192: + return fips_enabled ? NULL : &nist_p192; + case ECC_CURVE_NIST_P256: + return &nist_p256; + case ECC_CURVE_NIST_P384: + return &nist_p384; + default: + return NULL; + } +} +EXPORT_SYMBOL(ecc_get_curve); + +static u64 *ecc_alloc_digits_space(unsigned int ndigits) +{ + size_t len = ndigits * sizeof(u64); + + if (!len) + return NULL; + + return kmalloc(len, GFP_KERNEL); +} + +static void ecc_free_digits_space(u64 *space) +{ + kfree_sensitive(space); +} + +struct ecc_point *ecc_alloc_point(unsigned int ndigits) +{ + struct ecc_point *p = kmalloc(sizeof(*p), GFP_KERNEL); + + if (!p) + return NULL; + + p->x = ecc_alloc_digits_space(ndigits); + if (!p->x) + goto err_alloc_x; + + p->y = ecc_alloc_digits_space(ndigits); + if (!p->y) + goto err_alloc_y; + + p->ndigits = ndigits; + + return p; + +err_alloc_y: + ecc_free_digits_space(p->x); +err_alloc_x: + kfree(p); + return NULL; +} +EXPORT_SYMBOL(ecc_alloc_point); + +void ecc_free_point(struct ecc_point *p) +{ + if (!p) + return; + + kfree_sensitive(p->x); + kfree_sensitive(p->y); + kfree_sensitive(p); +} +EXPORT_SYMBOL(ecc_free_point); + +static void vli_clear(u64 *vli, unsigned int ndigits) +{ + int i; + + for (i = 0; i < ndigits; i++) + vli[i] = 0; +} + +/* Returns true if vli == 0, false otherwise. */ +bool vli_is_zero(const u64 *vli, unsigned int ndigits) +{ + int i; + + for (i = 0; i < ndigits; i++) { + if (vli[i]) + return false; + } + + return true; +} +EXPORT_SYMBOL(vli_is_zero); + +/* Returns nonzero if bit of vli is set. */ +static u64 vli_test_bit(const u64 *vli, unsigned int bit) +{ + return (vli[bit / 64] & ((u64)1 << (bit % 64))); +} + +static bool vli_is_negative(const u64 *vli, unsigned int ndigits) +{ + return vli_test_bit(vli, ndigits * 64 - 1); +} + +/* Counts the number of 64-bit "digits" in vli. */ +static unsigned int vli_num_digits(const u64 *vli, unsigned int ndigits) +{ + 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 = ndigits - 1; i >= 0 && vli[i] == 0; i--); + + return (i + 1); +} + +/* Counts the number of bits required for vli. */ +unsigned int vli_num_bits(const u64 *vli, unsigned int ndigits) +{ + unsigned int i, num_digits; + u64 digit; + + num_digits = vli_num_digits(vli, ndigits); + if (num_digits == 0) + return 0; + + digit = vli[num_digits - 1]; + for (i = 0; digit; i++) + digit >>= 1; + + return ((num_digits - 1) * 64 + i); +} +EXPORT_SYMBOL(vli_num_bits); + +/* Set dest from unaligned bit string src. */ +void vli_from_be64(u64 *dest, const void *src, unsigned int ndigits) +{ + int i; + const u64 *from = src; + + for (i = 0; i < ndigits; i++) + dest[i] = get_unaligned_be64(&from[ndigits - 1 - i]); +} +EXPORT_SYMBOL(vli_from_be64); + +void vli_from_le64(u64 *dest, const void *src, unsigned int ndigits) +{ + int i; + const u64 *from = src; + + for (i = 0; i < ndigits; i++) + dest[i] = get_unaligned_le64(&from[i]); +} +EXPORT_SYMBOL(vli_from_le64); + +/* Sets dest = src. */ +static void vli_set(u64 *dest, const u64 *src, unsigned int ndigits) +{ + int i; + + for (i = 0; i < ndigits; i++) + dest[i] = src[i]; +} + +/* Returns sign of left - right. */ +int vli_cmp(const u64 *left, const u64 *right, unsigned int ndigits) +{ + int i; + + for (i = ndigits - 1; i >= 0; i--) { + if (left[i] > right[i]) + return 1; + else if (left[i] < right[i]) + return -1; + } + + return 0; +} +EXPORT_SYMBOL(vli_cmp); + +/* 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, + unsigned int ndigits) +{ + u64 carry = 0; + int i; + + for (i = 0; i < ndigits; 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, unsigned int ndigits) +{ + u64 *end = vli; + u64 carry = 0; + + vli += ndigits; + + 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, + unsigned int ndigits) +{ + u64 carry = 0; + int i; + + for (i = 0; i < ndigits; 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 carry. Can modify in place. */ +static u64 vli_uadd(u64 *result, const u64 *left, u64 right, + unsigned int ndigits) +{ + u64 carry = right; + int i; + + for (i = 0; i < ndigits; i++) { + u64 sum; + + sum = left[i] + carry; + if (sum != left[i]) + carry = (sum < left[i]); + else + carry = !!carry; + + result[i] = sum; + } + + return carry; +} + +/* Computes result = left - right, returning borrow. Can modify in place. */ +u64 vli_sub(u64 *result, const u64 *left, const u64 *right, + unsigned int ndigits) +{ + u64 borrow = 0; + int i; + + for (i = 0; i < ndigits; i++) { + u64 diff; + + diff = left[i] - right[i] - borrow; + if (diff != left[i]) + borrow = (diff > left[i]); + + result[i] = diff; + } + + return borrow; +} +EXPORT_SYMBOL(vli_sub); + +/* Computes result = left - right, returning borrow. Can modify in place. */ +static u64 vli_usub(u64 *result, const u64 *left, u64 right, + unsigned int ndigits) +{ + u64 borrow = right; + int i; + + for (i = 0; i < ndigits; i++) { + u64 diff; + + diff = left[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) +{ + uint128_t result; +#if defined(CONFIG_ARCH_SUPPORTS_INT128) + unsigned __int128 m = (unsigned __int128)left * right; + + result.m_low = m; + result.m_high = m >> 64; +#else + 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; + + m2 += (m0 >> 32); + m2 += m1; + + /* Overflow */ + if (m2 < m1) + m3 += 0x100000000ull; + + result.m_low = (m0 & 0xffffffffull) | (m2 << 32); + result.m_high = m3 + (m2 >> 32); +#endif + 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, + unsigned int ndigits) +{ + 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 < ndigits * 2 - 1; k++) { + unsigned int min; + + if (k < ndigits) + min = 0; + else + min = (k + 1) - ndigits; + + for (i = min; i <= k && i < ndigits; 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[ndigits * 2 - 1] = r01.m_low; +} + +/* Compute product = left * right, for a small right value. */ +static void vli_umult(u64 *result, const u64 *left, u32 right, + unsigned int ndigits) +{ + uint128_t r01 = { 0 }; + unsigned int k; + + for (k = 0; k < ndigits; k++) { + uint128_t product; + + product = mul_64_64(left[k], right); + r01 = add_128_128(r01, product); + /* no carry */ + result[k] = r01.m_low; + r01.m_low = r01.m_high; + r01.m_high = 0; + } + result[k] = r01.m_low; + for (++k; k < ndigits * 2; k++) + result[k] = 0; +} + +static void vli_square(u64 *result, const u64 *left, unsigned int ndigits) +{ + uint128_t r01 = { 0, 0 }; + u64 r2 = 0; + int i, k; + + for (k = 0; k < ndigits * 2 - 1; k++) { + unsigned int min; + + if (k < ndigits) + min = 0; + else + min = (k + 1) - ndigits; + + 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[ndigits * 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, unsigned int ndigits) +{ + u64 carry; + + carry = vli_add(result, left, right, ndigits); + + /* result > mod (result = mod + remainder), so subtract mod to + * get remainder. + */ + if (carry || vli_cmp(result, mod, ndigits) >= 0) + vli_sub(result, result, mod, ndigits); +} + +/* 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, unsigned int ndigits) +{ + u64 borrow = vli_sub(result, left, right, ndigits); + + /* 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, ndigits); +} + +/* + * Computes result = product % mod + * for special form moduli: p = 2^k-c, for small c (note the minus sign) + * + * References: + * R. Crandall, C. Pomerance. Prime Numbers: A Computational Perspective. + * 9 Fast Algorithms for Large-Integer Arithmetic. 9.2.3 Moduli of special form + * Algorithm 9.2.13 (Fast mod operation for special-form moduli). + */ +static void vli_mmod_special(u64 *result, const u64 *product, + const u64 *mod, unsigned int ndigits) +{ + u64 c = -mod[0]; + u64 t[ECC_MAX_DIGITS * 2]; + u64 r[ECC_MAX_DIGITS * 2]; + + vli_set(r, product, ndigits * 2); + while (!vli_is_zero(r + ndigits, ndigits)) { + vli_umult(t, r + ndigits, c, ndigits); + vli_clear(r + ndigits, ndigits); + vli_add(r, r, t, ndigits * 2); + } + vli_set(t, mod, ndigits); + vli_clear(t + ndigits, ndigits); + while (vli_cmp(r, t, ndigits * 2) >= 0) + vli_sub(r, r, t, ndigits * 2); + vli_set(result, r, ndigits); +} + +/* + * Computes result = product % mod + * for special form moduli: p = 2^{k-1}+c, for small c (note the plus sign) + * where k-1 does not fit into qword boundary by -1 bit (such as 255). + + * References (loosely based on): + * A. Menezes, P. van Oorschot, S. Vanstone. Handbook of Applied Cryptography. + * 14.3.4 Reduction methods for moduli of special form. Algorithm 14.47. + * URL: http://cacr.uwaterloo.ca/hac/about/chap14.pdf + * + * H. Cohen, G. Frey, R. Avanzi, C. Doche, T. Lange, K. Nguyen, F. Vercauteren. + * Handbook of Elliptic and Hyperelliptic Curve Cryptography. + * Algorithm 10.25 Fast reduction for special form moduli + */ +static void vli_mmod_special2(u64 *result, const u64 *product, + const u64 *mod, unsigned int ndigits) +{ + u64 c2 = mod[0] * 2; + u64 q[ECC_MAX_DIGITS]; + u64 r[ECC_MAX_DIGITS * 2]; + u64 m[ECC_MAX_DIGITS * 2]; /* expanded mod */ + int carry; /* last bit that doesn't fit into q */ + int i; + + vli_set(m, mod, ndigits); + vli_clear(m + ndigits, ndigits); + + vli_set(r, product, ndigits); + /* q and carry are top bits */ + vli_set(q, product + ndigits, ndigits); + vli_clear(r + ndigits, ndigits); + carry = vli_is_negative(r, ndigits); + if (carry) + r[ndigits - 1] &= (1ull << 63) - 1; + for (i = 1; carry || !vli_is_zero(q, ndigits); i++) { + u64 qc[ECC_MAX_DIGITS * 2]; + + vli_umult(qc, q, c2, ndigits); + if (carry) + vli_uadd(qc, qc, mod[0], ndigits * 2); + vli_set(q, qc + ndigits, ndigits); + vli_clear(qc + ndigits, ndigits); + carry = vli_is_negative(qc, ndigits); + if (carry) + qc[ndigits - 1] &= (1ull << 63) - 1; + if (i & 1) + vli_sub(r, r, qc, ndigits * 2); + else + vli_add(r, r, qc, ndigits * 2); + } + while (vli_is_negative(r, ndigits * 2)) + vli_add(r, r, m, ndigits * 2); + while (vli_cmp(r, m, ndigits * 2) >= 0) + vli_sub(r, r, m, ndigits * 2); + + vli_set(result, r, ndigits); +} + +/* + * Computes result = product % mod, where product is 2N words long. + * Reference: Ken MacKay's micro-ecc. + * Currently only designed to work for curve_p or curve_n. + */ +static void vli_mmod_slow(u64 *result, u64 *product, const u64 *mod, + unsigned int ndigits) +{ + u64 mod_m[2 * ECC_MAX_DIGITS]; + u64 tmp[2 * ECC_MAX_DIGITS]; + u64 *v[2] = { tmp, product }; + u64 carry = 0; + unsigned int i; + /* Shift mod so its highest set bit is at the maximum position. */ + int shift = (ndigits * 2 * 64) - vli_num_bits(mod, ndigits); + int word_shift = shift / 64; + int bit_shift = shift % 64; + + vli_clear(mod_m, word_shift); + if (bit_shift > 0) { + for (i = 0; i < ndigits; ++i) { + mod_m[word_shift + i] = (mod[i] << bit_shift) | carry; + carry = mod[i] >> (64 - bit_shift); + } + } else + vli_set(mod_m + word_shift, mod, ndigits); + + for (i = 1; shift >= 0; --shift) { + u64 borrow = 0; + unsigned int j; + + for (j = 0; j < ndigits * 2; ++j) { + u64 diff = v[i][j] - mod_m[j] - borrow; + + if (diff != v[i][j]) + borrow = (diff > v[i][j]); + v[1 - i][j] = diff; + } + i = !(i ^ borrow); /* Swap the index if there was no borrow */ + vli_rshift1(mod_m, ndigits); + mod_m[ndigits - 1] |= mod_m[ndigits] << (64 - 1); + vli_rshift1(mod_m + ndigits, ndigits); + } + vli_set(result, v[i], ndigits); +} + +/* Computes result = product % mod using Barrett's reduction with precomputed + * value mu appended to the mod after ndigits, mu = (2^{2w} / mod) and have + * length ndigits + 1, where mu * (2^w - 1) should not overflow ndigits + * boundary. + * + * Reference: + * R. Brent, P. Zimmermann. Modern Computer Arithmetic. 2010. + * 2.4.1 Barrett's algorithm. Algorithm 2.5. + */ +static void vli_mmod_barrett(u64 *result, u64 *product, const u64 *mod, + unsigned int ndigits) +{ + u64 q[ECC_MAX_DIGITS * 2]; + u64 r[ECC_MAX_DIGITS * 2]; + const u64 *mu = mod + ndigits; + + vli_mult(q, product + ndigits, mu, ndigits); + if (mu[ndigits]) + vli_add(q + ndigits, q + ndigits, product + ndigits, ndigits); + vli_mult(r, mod, q + ndigits, ndigits); + vli_sub(r, product, r, ndigits * 2); + while (!vli_is_zero(r + ndigits, ndigits) || + vli_cmp(r, mod, ndigits) != -1) { + u64 carry; + + carry = vli_sub(r, r, mod, ndigits); + vli_usub(r + ndigits, r + ndigits, carry, ndigits); + } + vli_set(result, r, ndigits); +} + +/* Computes p_result = p_product % curve_p. + * See algorithm 5 and 6 from + * http://www.isys.uni-klu.ac.at/PDF/2001-0126-MT.pdf + */ +static void vli_mmod_fast_192(u64 *result, const u64 *product, + const u64 *curve_prime, u64 *tmp) +{ + const unsigned int ndigits = 3; + int carry; + + vli_set(result, product, ndigits); + + vli_set(tmp, &product[3], ndigits); + carry = vli_add(result, result, tmp, ndigits); + + tmp[0] = 0; + tmp[1] = product[3]; + tmp[2] = product[4]; + carry += vli_add(result, result, tmp, ndigits); + + tmp[0] = tmp[1] = product[5]; + tmp[2] = 0; + carry += vli_add(result, result, tmp, ndigits); + + while (carry || vli_cmp(curve_prime, result, ndigits) != 1) + carry -= vli_sub(result, result, curve_prime, ndigits); +} + +/* Computes result = product % curve_prime + * from http://www.nsa.gov/ia/_files/nist-routines.pdf + */ +static void vli_mmod_fast_256(u64 *result, const u64 *product, + const u64 *curve_prime, u64 *tmp) +{ + int carry; + const unsigned int ndigits = 4; + + /* t */ + vli_set(result, product, ndigits); + + /* s1 */ + tmp[0] = 0; + tmp[1] = product[5] & 0xffffffff00000000ull; + tmp[2] = product[6]; + tmp[3] = product[7]; + carry = vli_lshift(tmp, tmp, 1, ndigits); + carry += vli_add(result, result, tmp, ndigits); + + /* 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, ndigits); + carry += vli_add(result, result, tmp, ndigits); + + /* s3 */ + tmp[0] = product[4]; + tmp[1] = product[5] & 0xffffffff; + tmp[2] = 0; + tmp[3] = product[7]; + carry += vli_add(result, result, tmp, ndigits); + + /* 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, ndigits); + + /* 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, ndigits); + + /* 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, ndigits); + + /* 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, ndigits); + + /* 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, ndigits); + + if (carry < 0) { + do { + carry += vli_add(result, result, curve_prime, ndigits); + } while (carry < 0); + } else { + while (carry || vli_cmp(curve_prime, result, ndigits) != 1) + carry -= vli_sub(result, result, curve_prime, ndigits); + } +} + +#define SL32OR32(x32, y32) (((u64)x32 << 32) | y32) +#define AND64H(x64) (x64 & 0xffFFffFF00000000ull) +#define AND64L(x64) (x64 & 0x00000000ffFFffFFull) + +/* Computes result = product % curve_prime + * from "Mathematical routines for the NIST prime elliptic curves" + */ +static void vli_mmod_fast_384(u64 *result, const u64 *product, + const u64 *curve_prime, u64 *tmp) +{ + int carry; + const unsigned int ndigits = 6; + + /* t */ + vli_set(result, product, ndigits); + + /* s1 */ + tmp[0] = 0; // 0 || 0 + tmp[1] = 0; // 0 || 0 + tmp[2] = SL32OR32(product[11], (product[10]>>32)); //a22||a21 + tmp[3] = product[11]>>32; // 0 ||a23 + tmp[4] = 0; // 0 || 0 + tmp[5] = 0; // 0 || 0 + carry = vli_lshift(tmp, tmp, 1, ndigits); + carry += vli_add(result, result, tmp, ndigits); + + /* s2 */ + tmp[0] = product[6]; //a13||a12 + tmp[1] = product[7]; //a15||a14 + tmp[2] = product[8]; //a17||a16 + tmp[3] = product[9]; //a19||a18 + tmp[4] = product[10]; //a21||a20 + tmp[5] = product[11]; //a23||a22 + carry += vli_add(result, result, tmp, ndigits); + + /* s3 */ + tmp[0] = SL32OR32(product[11], (product[10]>>32)); //a22||a21 + tmp[1] = SL32OR32(product[6], (product[11]>>32)); //a12||a23 + tmp[2] = SL32OR32(product[7], (product[6])>>32); //a14||a13 + tmp[3] = SL32OR32(product[8], (product[7]>>32)); //a16||a15 + tmp[4] = SL32OR32(product[9], (product[8]>>32)); //a18||a17 + tmp[5] = SL32OR32(product[10], (product[9]>>32)); //a20||a19 + carry += vli_add(result, result, tmp, ndigits); + + /* s4 */ + tmp[0] = AND64H(product[11]); //a23|| 0 + tmp[1] = (product[10]<<32); //a20|| 0 + tmp[2] = product[6]; //a13||a12 + tmp[3] = product[7]; //a15||a14 + tmp[4] = product[8]; //a17||a16 + tmp[5] = product[9]; //a19||a18 + carry += vli_add(result, result, tmp, ndigits); + + /* s5 */ + tmp[0] = 0; // 0|| 0 + tmp[1] = 0; // 0|| 0 + tmp[2] = product[10]; //a21||a20 + tmp[3] = product[11]; //a23||a22 + tmp[4] = 0; // 0|| 0 + tmp[5] = 0; // 0|| 0 + carry += vli_add(result, result, tmp, ndigits); + + /* s6 */ + tmp[0] = AND64L(product[10]); // 0 ||a20 + tmp[1] = AND64H(product[10]); //a21|| 0 + tmp[2] = product[11]; //a23||a22 + tmp[3] = 0; // 0 || 0 + tmp[4] = 0; // 0 || 0 + tmp[5] = 0; // 0 || 0 + carry += vli_add(result, result, tmp, ndigits); + + /* d1 */ + tmp[0] = SL32OR32(product[6], (product[11]>>32)); //a12||a23 + tmp[1] = SL32OR32(product[7], (product[6]>>32)); //a14||a13 + tmp[2] = SL32OR32(product[8], (product[7]>>32)); //a16||a15 + tmp[3] = SL32OR32(product[9], (product[8]>>32)); //a18||a17 + tmp[4] = SL32OR32(product[10], (product[9]>>32)); //a20||a19 + tmp[5] = SL32OR32(product[11], (product[10]>>32)); //a22||a21 + carry -= vli_sub(result, result, tmp, ndigits); + + /* d2 */ + tmp[0] = (product[10]<<32); //a20|| 0 + tmp[1] = SL32OR32(product[11], (product[10]>>32)); //a22||a21 + tmp[2] = (product[11]>>32); // 0 ||a23 + tmp[3] = 0; // 0 || 0 + tmp[4] = 0; // 0 || 0 + tmp[5] = 0; // 0 || 0 + carry -= vli_sub(result, result, tmp, ndigits); + + /* d3 */ + tmp[0] = 0; // 0 || 0 + tmp[1] = AND64H(product[11]); //a23|| 0 + tmp[2] = product[11]>>32; // 0 ||a23 + tmp[3] = 0; // 0 || 0 + tmp[4] = 0; // 0 || 0 + tmp[5] = 0; // 0 || 0 + carry -= vli_sub(result, result, tmp, ndigits); + + if (carry < 0) { + do { + carry += vli_add(result, result, curve_prime, ndigits); + } while (carry < 0); + } else { + while (carry || vli_cmp(curve_prime, result, ndigits) != 1) + carry -= vli_sub(result, result, curve_prime, ndigits); + } + +} + +#undef SL32OR32 +#undef AND64H +#undef AND64L + +/* Computes result = product % curve_prime for different curve_primes. + * + * Note that curve_primes are distinguished just by heuristic check and + * not by complete conformance check. + */ +static bool vli_mmod_fast(u64 *result, u64 *product, + const struct ecc_curve *curve) +{ + u64 tmp[2 * ECC_MAX_DIGITS]; + const u64 *curve_prime = curve->p; + const unsigned int ndigits = curve->g.ndigits; + + /* All NIST curves have name prefix 'nist_' */ + if (strncmp(curve->name, "nist_", 5) != 0) { + /* Try to handle Pseudo-Marsenne primes. */ + if (curve_prime[ndigits - 1] == -1ull) { + vli_mmod_special(result, product, curve_prime, + ndigits); + return true; + } else if (curve_prime[ndigits - 1] == 1ull << 63 && + curve_prime[ndigits - 2] == 0) { + vli_mmod_special2(result, product, curve_prime, + ndigits); + return true; + } + vli_mmod_barrett(result, product, curve_prime, ndigits); + return true; + } + + switch (ndigits) { + case 3: + vli_mmod_fast_192(result, product, curve_prime, tmp); + break; + case 4: + vli_mmod_fast_256(result, product, curve_prime, tmp); + break; + case 6: + vli_mmod_fast_384(result, product, curve_prime, tmp); + break; + default: + pr_err_ratelimited("ecc: unsupported digits size!\n"); + return false; + } + + return true; +} + +/* Computes result = (left * right) % mod. + * Assumes that mod is big enough curve order. + */ +void vli_mod_mult_slow(u64 *result, const u64 *left, const u64 *right, + const u64 *mod, unsigned int ndigits) +{ + u64 product[ECC_MAX_DIGITS * 2]; + + vli_mult(product, left, right, ndigits); + vli_mmod_slow(result, product, mod, ndigits); +} +EXPORT_SYMBOL(vli_mod_mult_slow); + +/* Computes result = (left * right) % curve_prime. */ +static void vli_mod_mult_fast(u64 *result, const u64 *left, const u64 *right, + const struct ecc_curve *curve) +{ + u64 product[2 * ECC_MAX_DIGITS]; + + vli_mult(product, left, right, curve->g.ndigits); + vli_mmod_fast(result, product, curve); +} + +/* Computes result = left^2 % curve_prime. */ +static void vli_mod_square_fast(u64 *result, const u64 *left, + const struct ecc_curve *curve) +{ + u64 product[2 * ECC_MAX_DIGITS]; + + vli_square(product, left, curve->g.ndigits); + vli_mmod_fast(result, product, curve); +} + +#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 + */ +void vli_mod_inv(u64 *result, const u64 *input, const u64 *mod, + unsigned int ndigits) +{ + u64 a[ECC_MAX_DIGITS], b[ECC_MAX_DIGITS]; + u64 u[ECC_MAX_DIGITS], v[ECC_MAX_DIGITS]; + u64 carry; + int cmp_result; + + if (vli_is_zero(input, ndigits)) { + vli_clear(result, ndigits); + return; + } + + vli_set(a, input, ndigits); + vli_set(b, mod, ndigits); + vli_clear(u, ndigits); + u[0] = 1; + vli_clear(v, ndigits); + + while ((cmp_result = vli_cmp(a, b, ndigits)) != 0) { + carry = 0; + + if (EVEN(a)) { + vli_rshift1(a, ndigits); + + if (!EVEN(u)) + carry = vli_add(u, u, mod, ndigits); + + vli_rshift1(u, ndigits); + if (carry) + u[ndigits - 1] |= 0x8000000000000000ull; + } else if (EVEN(b)) { + vli_rshift1(b, ndigits); + + if (!EVEN(v)) + carry = vli_add(v, v, mod, ndigits); + + vli_rshift1(v, ndigits); + if (carry) + v[ndigits - 1] |= 0x8000000000000000ull; + } else if (cmp_result > 0) { + vli_sub(a, a, b, ndigits); + vli_rshift1(a, ndigits); + + if (vli_cmp(u, v, ndigits) < 0) + vli_add(u, u, mod, ndigits); + + vli_sub(u, u, v, ndigits); + if (!EVEN(u)) + carry = vli_add(u, u, mod, ndigits); + + vli_rshift1(u, ndigits); + if (carry) + u[ndigits - 1] |= 0x8000000000000000ull; + } else { + vli_sub(b, b, a, ndigits); + vli_rshift1(b, ndigits); + + if (vli_cmp(v, u, ndigits) < 0) + vli_add(v, v, mod, ndigits); + + vli_sub(v, v, u, ndigits); + if (!EVEN(v)) + carry = vli_add(v, v, mod, ndigits); + + vli_rshift1(v, ndigits); + if (carry) + v[ndigits - 1] |= 0x8000000000000000ull; + } + } + + vli_set(result, u, ndigits); +} +EXPORT_SYMBOL(vli_mod_inv); + +/* ------ Point operations ------ */ + +/* Returns true if p_point is the point at infinity, false otherwise. */ +bool ecc_point_is_zero(const struct ecc_point *point) +{ + return (vli_is_zero(point->x, point->ndigits) && + vli_is_zero(point->y, point->ndigits)); +} +EXPORT_SYMBOL(ecc_point_is_zero); + +/* Point multiplication algorithm using Montgomery's ladder with co-Z + * coordinates. From https://eprint.iacr.org/2011/338.pdf + */ + +/* Double in place */ +static void ecc_point_double_jacobian(u64 *x1, u64 *y1, u64 *z1, + const struct ecc_curve *curve) +{ + /* t1 = x, t2 = y, t3 = z */ + u64 t4[ECC_MAX_DIGITS]; + u64 t5[ECC_MAX_DIGITS]; + const u64 *curve_prime = curve->p; + const unsigned int ndigits = curve->g.ndigits; + + if (vli_is_zero(z1, ndigits)) + return; + + /* t4 = y1^2 */ + vli_mod_square_fast(t4, y1, curve); + /* t5 = x1*y1^2 = A */ + vli_mod_mult_fast(t5, x1, t4, curve); + /* t4 = y1^4 */ + vli_mod_square_fast(t4, t4, curve); + /* t2 = y1*z1 = z3 */ + vli_mod_mult_fast(y1, y1, z1, curve); + /* t3 = z1^2 */ + vli_mod_square_fast(z1, z1, curve); + + /* t1 = x1 + z1^2 */ + vli_mod_add(x1, x1, z1, curve_prime, ndigits); + /* t3 = 2*z1^2 */ + vli_mod_add(z1, z1, z1, curve_prime, ndigits); + /* t3 = x1 - z1^2 */ + vli_mod_sub(z1, x1, z1, curve_prime, ndigits); + /* t1 = x1^2 - z1^4 */ + vli_mod_mult_fast(x1, x1, z1, curve); + + /* t3 = 2*(x1^2 - z1^4) */ + vli_mod_add(z1, x1, x1, curve_prime, ndigits); + /* t1 = 3*(x1^2 - z1^4) */ + vli_mod_add(x1, x1, z1, curve_prime, ndigits); + if (vli_test_bit(x1, 0)) { + u64 carry = vli_add(x1, x1, curve_prime, ndigits); + + vli_rshift1(x1, ndigits); + x1[ndigits - 1] |= carry << 63; + } else { + vli_rshift1(x1, ndigits); + } + /* t1 = 3/2*(x1^2 - z1^4) = B */ + + /* t3 = B^2 */ + vli_mod_square_fast(z1, x1, curve); + /* t3 = B^2 - A */ + vli_mod_sub(z1, z1, t5, curve_prime, ndigits); + /* t3 = B^2 - 2A = x3 */ + vli_mod_sub(z1, z1, t5, curve_prime, ndigits); + /* t5 = A - x3 */ + vli_mod_sub(t5, t5, z1, curve_prime, ndigits); + /* t1 = B * (A - x3) */ + vli_mod_mult_fast(x1, x1, t5, curve); + /* t4 = B * (A - x3) - y1^4 = y3 */ + vli_mod_sub(t4, x1, t4, curve_prime, ndigits); + + vli_set(x1, z1, ndigits); + vli_set(z1, y1, ndigits); + vli_set(y1, t4, ndigits); +} + +/* Modify (x1, y1) => (x1 * z^2, y1 * z^3) */ +static void apply_z(u64 *x1, u64 *y1, u64 *z, const struct ecc_curve *curve) +{ + u64 t1[ECC_MAX_DIGITS]; + + vli_mod_square_fast(t1, z, curve); /* z^2 */ + vli_mod_mult_fast(x1, x1, t1, curve); /* x1 * z^2 */ + vli_mod_mult_fast(t1, t1, z, curve); /* z^3 */ + vli_mod_mult_fast(y1, y1, t1, curve); /* 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, const struct ecc_curve *curve) +{ + u64 z[ECC_MAX_DIGITS]; + const unsigned int ndigits = curve->g.ndigits; + + vli_set(x2, x1, ndigits); + vli_set(y2, y1, ndigits); + + vli_clear(z, ndigits); + z[0] = 1; + + if (p_initial_z) + vli_set(z, p_initial_z, ndigits); + + apply_z(x1, y1, z, curve); + + ecc_point_double_jacobian(x1, y1, z, curve); + + apply_z(x2, y2, z, curve); +} + +/* 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, + const struct ecc_curve *curve) +{ + /* t1 = X1, t2 = Y1, t3 = X2, t4 = Y2 */ + u64 t5[ECC_MAX_DIGITS]; + const u64 *curve_prime = curve->p; + const unsigned int ndigits = curve->g.ndigits; + + /* t5 = x2 - x1 */ + vli_mod_sub(t5, x2, x1, curve_prime, ndigits); + /* t5 = (x2 - x1)^2 = A */ + vli_mod_square_fast(t5, t5, curve); + /* t1 = x1*A = B */ + vli_mod_mult_fast(x1, x1, t5, curve); + /* t3 = x2*A = C */ + vli_mod_mult_fast(x2, x2, t5, curve); + /* t4 = y2 - y1 */ + vli_mod_sub(y2, y2, y1, curve_prime, ndigits); + /* t5 = (y2 - y1)^2 = D */ + vli_mod_square_fast(t5, y2, curve); + + /* t5 = D - B */ + vli_mod_sub(t5, t5, x1, curve_prime, ndigits); + /* t5 = D - B - C = x3 */ + vli_mod_sub(t5, t5, x2, curve_prime, ndigits); + /* t3 = C - B */ + vli_mod_sub(x2, x2, x1, curve_prime, ndigits); + /* t2 = y1*(C - B) */ + vli_mod_mult_fast(y1, y1, x2, curve); + /* t3 = B - x3 */ + vli_mod_sub(x2, x1, t5, curve_prime, ndigits); + /* t4 = (y2 - y1)*(B - x3) */ + vli_mod_mult_fast(y2, y2, x2, curve); + /* t4 = y3 */ + vli_mod_sub(y2, y2, y1, curve_prime, ndigits); + + vli_set(x2, t5, ndigits); +} + +/* 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, + const struct ecc_curve *curve) +{ + /* t1 = X1, t2 = Y1, t3 = X2, t4 = Y2 */ + u64 t5[ECC_MAX_DIGITS]; + u64 t6[ECC_MAX_DIGITS]; + u64 t7[ECC_MAX_DIGITS]; + const u64 *curve_prime = curve->p; + const unsigned int ndigits = curve->g.ndigits; + + /* t5 = x2 - x1 */ + vli_mod_sub(t5, x2, x1, curve_prime, ndigits); + /* t5 = (x2 - x1)^2 = A */ + vli_mod_square_fast(t5, t5, curve); + /* t1 = x1*A = B */ + vli_mod_mult_fast(x1, x1, t5, curve); + /* t3 = x2*A = C */ + vli_mod_mult_fast(x2, x2, t5, curve); + /* t4 = y2 + y1 */ + vli_mod_add(t5, y2, y1, curve_prime, ndigits); + /* t4 = y2 - y1 */ + vli_mod_sub(y2, y2, y1, curve_prime, ndigits); + + /* t6 = C - B */ + vli_mod_sub(t6, x2, x1, curve_prime, ndigits); + /* t2 = y1 * (C - B) */ + vli_mod_mult_fast(y1, y1, t6, curve); + /* t6 = B + C */ + vli_mod_add(t6, x1, x2, curve_prime, ndigits); + /* t3 = (y2 - y1)^2 */ + vli_mod_square_fast(x2, y2, curve); + /* t3 = x3 */ + vli_mod_sub(x2, x2, t6, curve_prime, ndigits); + + /* t7 = B - x3 */ + vli_mod_sub(t7, x1, x2, curve_prime, ndigits); + /* t4 = (y2 - y1)*(B - x3) */ + vli_mod_mult_fast(y2, y2, t7, curve); + /* t4 = y3 */ + vli_mod_sub(y2, y2, y1, curve_prime, ndigits); + + /* t7 = (y2 + y1)^2 = F */ + vli_mod_square_fast(t7, t5, curve); + /* t7 = x3' */ + vli_mod_sub(t7, t7, t6, curve_prime, ndigits); + /* t6 = x3' - B */ + vli_mod_sub(t6, t7, x1, curve_prime, ndigits); + /* t6 = (y2 + y1)*(x3' - B) */ + vli_mod_mult_fast(t6, t6, t5, curve); + /* t2 = y3' */ + vli_mod_sub(y1, t6, y1, curve_prime, ndigits); + + vli_set(x1, t7, ndigits); +} + +static void ecc_point_mult(struct ecc_point *result, + const struct ecc_point *point, const u64 *scalar, + u64 *initial_z, const struct ecc_curve *curve, + unsigned int ndigits) +{ + /* R0 and R1 */ + u64 rx[2][ECC_MAX_DIGITS]; + u64 ry[2][ECC_MAX_DIGITS]; + u64 z[ECC_MAX_DIGITS]; + u64 sk[2][ECC_MAX_DIGITS]; + u64 *curve_prime = curve->p; + int i, nb; + int num_bits; + int carry; + + carry = vli_add(sk[0], scalar, curve->n, ndigits); + vli_add(sk[1], sk[0], curve->n, ndigits); + scalar = sk[!carry]; + num_bits = sizeof(u64) * ndigits * 8 + 1; + + vli_set(rx[1], point->x, ndigits); + vli_set(ry[1], point->y, ndigits); + + xycz_initial_double(rx[1], ry[1], rx[0], ry[0], initial_z, curve); + + 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], curve); + xycz_add(rx[nb], ry[nb], rx[1 - nb], ry[1 - nb], curve); + } + + nb = !vli_test_bit(scalar, 0); + xycz_add_c(rx[1 - nb], ry[1 - nb], rx[nb], ry[nb], curve); + + /* Find final 1/Z value. */ + /* X1 - X0 */ + vli_mod_sub(z, rx[1], rx[0], curve_prime, ndigits); + /* Yb * (X1 - X0) */ + vli_mod_mult_fast(z, z, ry[1 - nb], curve); + /* xP * Yb * (X1 - X0) */ + vli_mod_mult_fast(z, z, point->x, curve); + + /* 1 / (xP * Yb * (X1 - X0)) */ + vli_mod_inv(z, z, curve_prime, point->ndigits); + + /* yP / (xP * Yb * (X1 - X0)) */ + vli_mod_mult_fast(z, z, point->y, curve); + /* Xb * yP / (xP * Yb * (X1 - X0)) */ + vli_mod_mult_fast(z, z, rx[1 - nb], curve); + /* End 1/Z calculation */ + + xycz_add(rx[nb], ry[nb], rx[1 - nb], ry[1 - nb], curve); + + apply_z(rx[0], ry[0], z, curve); + + vli_set(result->x, rx[0], ndigits); + vli_set(result->y, ry[0], ndigits); +} + +/* Computes R = P + Q mod p */ +static void ecc_point_add(const struct ecc_point *result, + const struct ecc_point *p, const struct ecc_point *q, + const struct ecc_curve *curve) +{ + u64 z[ECC_MAX_DIGITS]; + u64 px[ECC_MAX_DIGITS]; + u64 py[ECC_MAX_DIGITS]; + unsigned int ndigits = curve->g.ndigits; + + vli_set(result->x, q->x, ndigits); + vli_set(result->y, q->y, ndigits); + vli_mod_sub(z, result->x, p->x, curve->p, ndigits); + vli_set(px, p->x, ndigits); + vli_set(py, p->y, ndigits); + xycz_add(px, py, result->x, result->y, curve); + vli_mod_inv(z, z, curve->p, ndigits); + apply_z(result->x, result->y, z, curve); +} + +/* Computes R = u1P + u2Q mod p using Shamir's trick. + * Based on: Kenneth MacKay's micro-ecc (2014). + */ +void ecc_point_mult_shamir(const struct ecc_point *result, + const u64 *u1, const struct ecc_point *p, + const u64 *u2, const struct ecc_point *q, + const struct ecc_curve *curve) +{ + u64 z[ECC_MAX_DIGITS]; + u64 sump[2][ECC_MAX_DIGITS]; + u64 *rx = result->x; + u64 *ry = result->y; + unsigned int ndigits = curve->g.ndigits; + unsigned int num_bits; + struct ecc_point sum = ECC_POINT_INIT(sump[0], sump[1], ndigits); + const struct ecc_point *points[4]; + const struct ecc_point *point; + unsigned int idx; + int i; + + ecc_point_add(&sum, p, q, curve); + points[0] = NULL; + points[1] = p; + points[2] = q; + points[3] = ∑ + + num_bits = max(vli_num_bits(u1, ndigits), vli_num_bits(u2, ndigits)); + i = num_bits - 1; + idx = (!!vli_test_bit(u1, i)) | ((!!vli_test_bit(u2, i)) << 1); + point = points[idx]; + + vli_set(rx, point->x, ndigits); + vli_set(ry, point->y, ndigits); + vli_clear(z + 1, ndigits - 1); + z[0] = 1; + + for (--i; i >= 0; i--) { + ecc_point_double_jacobian(rx, ry, z, curve); + idx = (!!vli_test_bit(u1, i)) | ((!!vli_test_bit(u2, i)) << 1); + point = points[idx]; + if (point) { + u64 tx[ECC_MAX_DIGITS]; + u64 ty[ECC_MAX_DIGITS]; + u64 tz[ECC_MAX_DIGITS]; + + vli_set(tx, point->x, ndigits); + vli_set(ty, point->y, ndigits); + apply_z(tx, ty, z, curve); + vli_mod_sub(tz, rx, tx, curve->p, ndigits); + xycz_add(tx, ty, rx, ry, curve); + vli_mod_mult_fast(z, z, tz, curve); + } + } + vli_mod_inv(z, z, curve->p, ndigits); + apply_z(rx, ry, z, curve); +} +EXPORT_SYMBOL(ecc_point_mult_shamir); + +static int __ecc_is_key_valid(const struct ecc_curve *curve, + const u64 *private_key, unsigned int ndigits) +{ + u64 one[ECC_MAX_DIGITS] = { 1, }; + u64 res[ECC_MAX_DIGITS]; + + if (!private_key) + return -EINVAL; + + if (curve->g.ndigits != ndigits) + return -EINVAL; + + /* Make sure the private key is in the range [2, n-3]. */ + if (vli_cmp(one, private_key, ndigits) != -1) + return -EINVAL; + vli_sub(res, curve->n, one, ndigits); + vli_sub(res, res, one, ndigits); + if (vli_cmp(res, private_key, ndigits) != 1) + return -EINVAL; + + return 0; +} + +int ecc_is_key_valid(unsigned int curve_id, unsigned int ndigits, + const u64 *private_key, unsigned int private_key_len) +{ + int nbytes; + const struct ecc_curve *curve = ecc_get_curve(curve_id); + + nbytes = ndigits << ECC_DIGITS_TO_BYTES_SHIFT; + + if (private_key_len != nbytes) + return -EINVAL; + + return __ecc_is_key_valid(curve, private_key, ndigits); +} +EXPORT_SYMBOL(ecc_is_key_valid); + +/* + * ECC private keys are generated using the method of extra random bits, + * equivalent to that described in FIPS 186-4, Appendix B.4.1. + * + * d = (c mod(n–1)) + 1 where c is a string of random bits, 64 bits longer + * than requested + * 0 <= c mod(n-1) <= n-2 and implies that + * 1 <= d <= n-1 + * + * This method generates a private key uniformly distributed in the range + * [1, n-1]. + */ +int ecc_gen_privkey(unsigned int curve_id, unsigned int ndigits, u64 *privkey) +{ + const struct ecc_curve *curve = ecc_get_curve(curve_id); + u64 priv[ECC_MAX_DIGITS]; + unsigned int nbytes = ndigits << ECC_DIGITS_TO_BYTES_SHIFT; + unsigned int nbits = vli_num_bits(curve->n, ndigits); + int err; + + /* Check that N is included in Table 1 of FIPS 186-4, section 6.1.1 */ + if (nbits < 160 || ndigits > ARRAY_SIZE(priv)) + return -EINVAL; + + /* + * FIPS 186-4 recommends that the private key should be obtained from a + * RBG with a security strength equal to or greater than the security + * strength associated with N. + * + * The maximum security strength identified by NIST SP800-57pt1r4 for + * ECC is 256 (N >= 512). + * + * This condition is met by the default RNG because it selects a favored + * DRBG with a security strength of 256. + */ + if (crypto_get_default_rng()) + return -EFAULT; + + err = crypto_rng_get_bytes(crypto_default_rng, (u8 *)priv, nbytes); + crypto_put_default_rng(); + if (err) + return err; + + /* Make sure the private key is in the valid range. */ + if (__ecc_is_key_valid(curve, priv, ndigits)) + return -EINVAL; + + ecc_swap_digits(priv, privkey, ndigits); + + return 0; +} +EXPORT_SYMBOL(ecc_gen_privkey); + +int ecc_make_pub_key(unsigned int curve_id, unsigned int ndigits, + const u64 *private_key, u64 *public_key) +{ + int ret = 0; + struct ecc_point *pk; + u64 priv[ECC_MAX_DIGITS]; + const struct ecc_curve *curve = ecc_get_curve(curve_id); + + if (!private_key || !curve || ndigits > ARRAY_SIZE(priv)) { + ret = -EINVAL; + goto out; + } + + ecc_swap_digits(private_key, priv, ndigits); + + pk = ecc_alloc_point(ndigits); + if (!pk) { + ret = -ENOMEM; + goto out; + } + + ecc_point_mult(pk, &curve->g, priv, NULL, curve, ndigits); + + /* SP800-56A rev 3 5.6.2.1.3 key check */ + if (ecc_is_pubkey_valid_full(curve, pk)) { + ret = -EAGAIN; + goto err_free_point; + } + + ecc_swap_digits(pk->x, public_key, ndigits); + ecc_swap_digits(pk->y, &public_key[ndigits], ndigits); + +err_free_point: + ecc_free_point(pk); +out: + return ret; +} +EXPORT_SYMBOL(ecc_make_pub_key); + +/* SP800-56A section 5.6.2.3.4 partial verification: ephemeral keys only */ +int ecc_is_pubkey_valid_partial(const struct ecc_curve *curve, + struct ecc_point *pk) +{ + u64 yy[ECC_MAX_DIGITS], xxx[ECC_MAX_DIGITS], w[ECC_MAX_DIGITS]; + + if (WARN_ON(pk->ndigits != curve->g.ndigits)) + return -EINVAL; + + /* Check 1: Verify key is not the zero point. */ + if (ecc_point_is_zero(pk)) + return -EINVAL; + + /* Check 2: Verify key is in the range [1, p-1]. */ + if (vli_cmp(curve->p, pk->x, pk->ndigits) != 1) + return -EINVAL; + if (vli_cmp(curve->p, pk->y, pk->ndigits) != 1) + return -EINVAL; + + /* Check 3: Verify that y^2 == (x^3 + a·x + b) mod p */ + vli_mod_square_fast(yy, pk->y, curve); /* y^2 */ + vli_mod_square_fast(xxx, pk->x, curve); /* x^2 */ + vli_mod_mult_fast(xxx, xxx, pk->x, curve); /* x^3 */ + vli_mod_mult_fast(w, curve->a, pk->x, curve); /* a·x */ + vli_mod_add(w, w, curve->b, curve->p, pk->ndigits); /* a·x + b */ + vli_mod_add(w, w, xxx, curve->p, pk->ndigits); /* x^3 + a·x + b */ + if (vli_cmp(yy, w, pk->ndigits) != 0) /* Equation */ + return -EINVAL; + + return 0; +} +EXPORT_SYMBOL(ecc_is_pubkey_valid_partial); + +/* SP800-56A section 5.6.2.3.3 full verification */ +int ecc_is_pubkey_valid_full(const struct ecc_curve *curve, + struct ecc_point *pk) +{ + struct ecc_point *nQ; + + /* Checks 1 through 3 */ + int ret = ecc_is_pubkey_valid_partial(curve, pk); + + if (ret) + return ret; + + /* Check 4: Verify that nQ is the zero point. */ + nQ = ecc_alloc_point(pk->ndigits); + if (!nQ) + return -ENOMEM; + + ecc_point_mult(nQ, pk, curve->n, NULL, curve, pk->ndigits); + if (!ecc_point_is_zero(nQ)) + ret = -EINVAL; + + ecc_free_point(nQ); + + return ret; +} +EXPORT_SYMBOL(ecc_is_pubkey_valid_full); + +int crypto_ecdh_shared_secret(unsigned int curve_id, unsigned int ndigits, + const u64 *private_key, const u64 *public_key, + u64 *secret) +{ + int ret = 0; + struct ecc_point *product, *pk; + u64 priv[ECC_MAX_DIGITS]; + u64 rand_z[ECC_MAX_DIGITS]; + unsigned int nbytes; + const struct ecc_curve *curve = ecc_get_curve(curve_id); + + if (!private_key || !public_key || !curve || + ndigits > ARRAY_SIZE(priv) || ndigits > ARRAY_SIZE(rand_z)) { + ret = -EINVAL; + goto out; + } + + nbytes = ndigits << ECC_DIGITS_TO_BYTES_SHIFT; + + get_random_bytes(rand_z, nbytes); + + pk = ecc_alloc_point(ndigits); + if (!pk) { + ret = -ENOMEM; + goto out; + } + + ecc_swap_digits(public_key, pk->x, ndigits); + ecc_swap_digits(&public_key[ndigits], pk->y, ndigits); + ret = ecc_is_pubkey_valid_partial(curve, pk); + if (ret) + goto err_alloc_product; + + ecc_swap_digits(private_key, priv, ndigits); + + product = ecc_alloc_point(ndigits); + if (!product) { + ret = -ENOMEM; + goto err_alloc_product; + } + + ecc_point_mult(product, pk, priv, rand_z, curve, ndigits); + + if (ecc_point_is_zero(product)) { + ret = -EFAULT; + goto err_validity; + } + + ecc_swap_digits(product->x, secret, ndigits); + +err_validity: + memzero_explicit(priv, sizeof(priv)); + memzero_explicit(rand_z, sizeof(rand_z)); + ecc_free_point(product); +err_alloc_product: + ecc_free_point(pk); +out: + return ret; +} +EXPORT_SYMBOL(crypto_ecdh_shared_secret); + +MODULE_LICENSE("Dual BSD/GPL"); -- cgit v1.2.3