Release 4.11 crypto/ecc.c
/*
* 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 <linux/slab.h>
#include <linux/swab.h>
#include <linux/fips.h>
#include <crypto/ecdh.h>
#include "ecc.h"
#include "ecc_curve_defs.h"
typedef struct {
u64 m_low;
u64 m_high;
}
uint128_t;
static inline 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;
default:
return NULL;
}
}
Contributors
Person | Tokens | Prop | Commits | CommitProp |
Salvatore Benedetto | 43 | 100.00% | 1 | 100.00% |
Total | 43 | 100.00% | 1 | 100.00% |
static u64 *ecc_alloc_digits_space(unsigned int ndigits)
{
size_t len = ndigits * sizeof(u64);
if (!len)
return NULL;
return kmalloc(len, GFP_KERNEL);
}
Contributors
Person | Tokens | Prop | Commits | CommitProp |
Salvatore Benedetto | 37 | 100.00% | 1 | 100.00% |
Total | 37 | 100.00% | 1 | 100.00% |
static void ecc_free_digits_space(u64 *space)
{
kzfree(space);
}
Contributors
Person | Tokens | Prop | Commits | CommitProp |
Salvatore Benedetto | 15 | 100.00% | 1 | 100.00% |
Total | 15 | 100.00% | 1 | 100.00% |
static 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;
}
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Salvatore Benedetto | 102 | 100.00% | 1 | 100.00% |
Total | 102 | 100.00% | 1 | 100.00% |
static void ecc_free_point(struct ecc_point *p)
{
if (!p)
return;
kzfree(p->x);
kzfree(p->y);
kzfree(p);
}
Contributors
Person | Tokens | Prop | Commits | CommitProp |
Salvatore Benedetto | 36 | 100.00% | 1 | 100.00% |
Total | 36 | 100.00% | 1 | 100.00% |
static void vli_clear(u64 *vli, unsigned int ndigits)
{
int i;
for (i = 0; i < ndigits; i++)
vli[i] = 0;
}
Contributors
Person | Tokens | Prop | Commits | CommitProp |
Salvatore Benedetto | 37 | 100.00% | 1 | 100.00% |
Total | 37 | 100.00% | 1 | 100.00% |
/* Returns true if vli == 0, false otherwise. */
static 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;
}
Contributors
Person | Tokens | Prop | Commits | CommitProp |
Salvatore Benedetto | 46 | 100.00% | 1 | 100.00% |
Total | 46 | 100.00% | 1 | 100.00% |
/* 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)));
}
Contributors
Person | Tokens | Prop | Commits | CommitProp |
Salvatore Benedetto | 38 | 100.00% | 1 | 100.00% |
Total | 38 | 100.00% | 1 | 100.00% |
/* 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);
}
Contributors
Person | Tokens | Prop | Commits | CommitProp |
Salvatore Benedetto | 50 | 100.00% | 1 | 100.00% |
Total | 50 | 100.00% | 1 | 100.00% |
/* Counts the number of bits required for vli. */
static 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);
}
Contributors
Person | Tokens | Prop | Commits | CommitProp |
Salvatore Benedetto | 80 | 100.00% | 1 | 100.00% |
Total | 80 | 100.00% | 1 | 100.00% |
/* 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];
}
Contributors
Person | Tokens | Prop | Commits | CommitProp |
Salvatore Benedetto | 45 | 100.00% | 1 | 100.00% |
Total | 45 | 100.00% | 1 | 100.00% |
/* Returns sign of left - right. */
static 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;
}
Contributors
Person | Tokens | Prop | Commits | CommitProp |
Salvatore Benedetto | 75 | 100.00% | 1 | 100.00% |
Total | 75 | 100.00% | 1 | 100.00% |
/* 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;
}
Contributors
Person | Tokens | Prop | Commits | CommitProp |
Salvatore Benedetto | 80 | 100.00% | 1 | 100.00% |
Total | 80 | 100.00% | 1 | 100.00% |
/* 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;
}
}
Contributors
Person | Tokens | Prop | Commits | CommitProp |
Salvatore Benedetto | 61 | 100.00% | 1 | 100.00% |
Total | 61 | 100.00% | 1 | 100.00% |
/* 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;
}
Contributors
Person | Tokens | Prop | Commits | CommitProp |
Salvatore Benedetto | 94 | 100.00% | 1 | 100.00% |
Total | 94 | 100.00% | 1 | 100.00% |
/* Computes result = left - right, returning borrow. Can modify in place. */
static 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;
}
Contributors
Person | Tokens | Prop | Commits | CommitProp |
Salvatore Benedetto | 94 | 100.00% | 1 | 100.00% |
Total | 94 | 100.00% | 1 | 100.00% |
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;
}
Contributors
Person | Tokens | Prop | Commits | CommitProp |
Salvatore Benedetto | 125 | 100.00% | 1 | 100.00% |
Total | 125 | 100.00% | 1 | 100.00% |
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;
}
Contributors
Person | Tokens | Prop | Commits | CommitProp |
Salvatore Benedetto | 52 | 100.00% | 1 | 100.00% |
Total | 52 | 100.00% | 1 | 100.00% |
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;
}
Contributors
Person | Tokens | Prop | Commits | CommitProp |
Salvatore Benedetto | 189 | 100.00% | 1 | 100.00% |
Total | 189 | 100.00% | 1 | 100.00% |
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;
}
Contributors
Person | Tokens | Prop | Commits | CommitProp |
Salvatore Benedetto | 228 | 100.00% | 1 | 100.00% |
Total | 228 | 100.00% | 1 | 100.00% |
/* 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);
}
Contributors
Person | Tokens | Prop | Commits | CommitProp |
Salvatore Benedetto | 72 | 100.00% | 1 | 100.00% |
Total | 72 | 100.00% | 1 | 100.00% |
/* 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);
}
Contributors
Person | Tokens | Prop | Commits | CommitProp |
Salvatore Benedetto | 59 | 100.00% | 1 | 100.00% |
Total | 59 | 100.00% | 1 | 100.00% |
/* 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);
}
Contributors
Person | Tokens | Prop | Commits | CommitProp |
Salvatore Benedetto | 172 | 100.00% | 1 | 100.00% |
Total | 172 | 100.00% | 1 | 100.00% |
/* 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);
}
}
Contributors
Person | Tokens | Prop | Commits | CommitProp |
Salvatore Benedetto | 692 | 100.00% | 1 | 100.00% |
Total | 692 | 100.00% | 1 | 100.00% |
/* Computes result = product % curve_prime
* from http://www.nsa.gov/ia/_files/nist-routines.pdf
*/
static bool vli_mmod_fast(u64 *result, u64 *product,
const u64 *curve_prime, unsigned int ndigits)
{
u64 tmp[2 * ndigits];
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;
default:
pr_err("unsupports digits size!\n");
return false;
}
return true;
}
Contributors
Person | Tokens | Prop | Commits | CommitProp |
Salvatore Benedetto | 79 | 100.00% | 1 | 100.00% |
Total | 79 | 100.00% | 1 | 100.00% |
/* Computes result = (left * right) % curve_prime. */
static void vli_mod_mult_fast(u64 *result, const u64 *left, const u64 *right,
const u64 *curve_prime, unsigned int ndigits)
{
u64 product[2 * ndigits];
vli_mult(product, left, right, ndigits);
vli_mmod_fast(result, product, curve_prime, ndigits);
}
Contributors
Person | Tokens | Prop | Commits | CommitProp |
Salvatore Benedetto | 59 | 100.00% | 1 | 100.00% |
Total | 59 | 100.00% | 1 | 100.00% |
/* Computes result = left^2 % curve_prime. */
static void vli_mod_square_fast(u64 *result, const u64 *left,
const u64 *curve_prime, unsigned int ndigits)
{
u64 product[2 * ndigits];
vli_square(product, left, ndigits);
vli_mmod_fast(result, product, curve_prime, ndigits);
}
Contributors
Person | Tokens | Prop | Commits | CommitProp |
Salvatore Benedetto | 52 | 100.00% | 1 | 100.00% |
Total | 52 | 100.00% | 1 | 100.00% |
#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,
unsigned int ndigits)
{
u64 a[ndigits], b[ndigits];
u64 u[ndigits], v[ndigits];
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