RetroZilla/security/nss/lib/freebl/ecl/curve25519_32.c
Roy Tam 1c9b432ff7 ported changes from tenfourfox:
M1357599, M923089+M1276618+M1278434, M1485864, M1520826, M1558548, #481-X25519, M1586176

with custom changes:
- coreconf+makefiles: set NSS_NO_PKCS11_BYPASS by default (to disable, set NSS_PKCS11_BYPASS) and fix logic
- curve25519_32: use PRuint32 instead of uint32_t
- smime: fix decl on top of block
- ssl3con: more VC6 fixes
2020-01-08 07:39:56 +08:00

394 lines
8.0 KiB
C

/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/*
* Derived from public domain code by Matthew Dempsky and D. J. Bernstein.
*/
#include "ecl-priv.h"
#include "mpi.h"
#include <stdio.h>
#include "seccomon.h"
#include "secerr.h"
#include "prtypes.h"
typedef PRUint32 elem[32];
/*
* Add two field elements.
* out = a + b
*/
static void
add(elem out, const elem a, const elem b)
{
PRUint32 j;
PRUint32 u = 0;
for (j = 0; j < 31; ++j) {
u += a[j] + b[j];
out[j] = u & 0xFF;
u >>= 8;
}
u += a[31] + b[31];
out[31] = u;
}
/*
* Subtract two field elements.
* out = a - b
*/
static void
sub(elem out, const elem a, const elem b)
{
PRUint32 j;
PRUint32 u;
u = 218;
for (j = 0; j < 31; ++j) {
u += a[j] + 0xFF00 - b[j];
out[j] = u & 0xFF;
u >>= 8;
}
u += a[31] - b[31];
out[31] = u;
}
/*
* "Squeeze" an element after multiplication (and square).
*/
static void
squeeze(elem a)
{
PRUint32 j;
PRUint32 u;
u = 0;
for (j = 0; j < 31; ++j) {
u += a[j];
a[j] = u & 0xFF;
u >>= 8;
}
u += a[31];
a[31] = u & 0x7F;
u = 19 * (u >> 7);
for (j = 0; j < 31; ++j) {
u += a[j];
a[j] = u & 0xFF;
u >>= 8;
}
a[31] += u;
}
static const elem minusp = { 19, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 128 };
/*
* Reduce point a by 2^255-19
*/
static void
reduce(elem a)
{
elem aorig;
PRUint32 j;
PRUint32 negative;
for (j = 0; j < 32; ++j) {
aorig[j] = a[j];
}
add(a, a, minusp);
negative = 1 + ~((a[31] >> 7) & 1);
for (j = 0; j < 32; ++j) {
a[j] ^= negative & (aorig[j] ^ a[j]);
}
}
/*
* Multiplication and squeeze
* out = a * b
*/
static void
mult(elem out, const elem a, const elem b)
{
PRUint32 i;
PRUint32 j;
PRUint32 u;
for (i = 0; i < 32; ++i) {
u = 0;
for (j = 0; j <= i; ++j) {
u += a[j] * b[i - j];
}
for (j = i + 1; j < 32; ++j) {
u += 38 * a[j] * b[i + 32 - j];
}
out[i] = u;
}
squeeze(out);
}
/*
* Multiplication
* out = 121665 * a
*/
static void
mult121665(elem out, const elem a)
{
PRUint32 j;
PRUint32 u;
u = 0;
for (j = 0; j < 31; ++j) {
u += 121665 * a[j];
out[j] = u & 0xFF;
u >>= 8;
}
u += 121665 * a[31];
out[31] = u & 0x7F;
u = 19 * (u >> 7);
for (j = 0; j < 31; ++j) {
u += out[j];
out[j] = u & 0xFF;
u >>= 8;
}
u += out[j];
out[j] = u;
}
/*
* Square a and squeeze the result.
* out = a * a
*/
static void
square(elem out, const elem a)
{
PRUint32 i;
PRUint32 j;
PRUint32 u;
for (i = 0; i < 32; ++i) {
u = 0;
for (j = 0; j < i - j; ++j) {
u += a[j] * a[i - j];
}
for (j = i + 1; j < i + 32 - j; ++j) {
u += 38 * a[j] * a[i + 32 - j];
}
u *= 2;
if ((i & 1) == 0) {
u += a[i / 2] * a[i / 2];
u += 38 * a[i / 2 + 16] * a[i / 2 + 16];
}
out[i] = u;
}
squeeze(out);
}
/*
* Constant time swap between r and s depending on b
*/
static void
cswap(PRUint32 p[64], PRUint32 q[64], PRUint32 b)
{
PRUint32 j;
PRUint32 swap = 1 + ~b;
for (j = 0; j < 64; ++j) {
const PRUint32 t = swap & (p[j] ^ q[j]);
p[j] ^= t;
q[j] ^= t;
}
}
/*
* Montgomery ladder
*/
static void
monty(elem x_2_out, elem z_2_out,
const elem point, const elem scalar)
{
PRUint32 x_3[64] = { 0 };
PRUint32 x_2[64] = { 0 };
PRUint32 a0[64];
PRUint32 a1[64];
PRUint32 b0[64];
PRUint32 b1[64];
PRUint32 c1[64];
PRUint32 r[32];
PRUint32 s[32];
PRUint32 t[32];
PRUint32 u[32];
PRUint32 swap = 0;
PRUint32 k_t = 0;
int j;
for (j = 0; j < 32; ++j) {
x_3[j] = point[j];
}
x_3[32] = 1;
x_2[0] = 1;
for (j = 254; j >= 0; --j) {
k_t = (scalar[j >> 3] >> (j & 7)) & 1;
swap ^= k_t;
cswap(x_2, x_3, swap);
swap = k_t;
add(a0, x_2, x_2 + 32);
sub(a0 + 32, x_2, x_2 + 32);
add(a1, x_3, x_3 + 32);
sub(a1 + 32, x_3, x_3 + 32);
square(b0, a0);
square(b0 + 32, a0 + 32);
mult(b1, a1, a0 + 32);
mult(b1 + 32, a1 + 32, a0);
add(c1, b1, b1 + 32);
sub(c1 + 32, b1, b1 + 32);
square(r, c1 + 32);
sub(s, b0, b0 + 32);
mult121665(t, s);
add(u, t, b0);
mult(x_2, b0, b0 + 32);
mult(x_2 + 32, s, u);
square(x_3, c1);
mult(x_3 + 32, r, point);
}
cswap(x_2, x_3, swap);
for (j = 0; j < 32; ++j) {
x_2_out[j] = x_2[j];
}
for (j = 0; j < 32; ++j) {
z_2_out[j] = x_2[j + 32];
}
}
static void
recip(elem out, const elem z)
{
elem z2;
elem z9;
elem z11;
elem z2_5_0;
elem z2_10_0;
elem z2_20_0;
elem z2_50_0;
elem z2_100_0;
elem t0;
elem t1;
int i;
/* 2 */ square(z2, z);
/* 4 */ square(t1, z2);
/* 8 */ square(t0, t1);
/* 9 */ mult(z9, t0, z);
/* 11 */ mult(z11, z9, z2);
/* 22 */ square(t0, z11);
/* 2^5 - 2^0 = 31 */ mult(z2_5_0, t0, z9);
/* 2^6 - 2^1 */ square(t0, z2_5_0);
/* 2^7 - 2^2 */ square(t1, t0);
/* 2^8 - 2^3 */ square(t0, t1);
/* 2^9 - 2^4 */ square(t1, t0);
/* 2^10 - 2^5 */ square(t0, t1);
/* 2^10 - 2^0 */ mult(z2_10_0, t0, z2_5_0);
/* 2^11 - 2^1 */ square(t0, z2_10_0);
/* 2^12 - 2^2 */ square(t1, t0);
/* 2^20 - 2^10 */
for (i = 2; i < 10; i += 2) {
square(t0, t1);
square(t1, t0);
}
/* 2^20 - 2^0 */ mult(z2_20_0, t1, z2_10_0);
/* 2^21 - 2^1 */ square(t0, z2_20_0);
/* 2^22 - 2^2 */ square(t1, t0);
/* 2^40 - 2^20 */
for (i = 2; i < 20; i += 2) {
square(t0, t1);
square(t1, t0);
}
/* 2^40 - 2^0 */ mult(t0, t1, z2_20_0);
/* 2^41 - 2^1 */ square(t1, t0);
/* 2^42 - 2^2 */ square(t0, t1);
/* 2^50 - 2^10 */
for (i = 2; i < 10; i += 2) {
square(t1, t0);
square(t0, t1);
}
/* 2^50 - 2^0 */ mult(z2_50_0, t0, z2_10_0);
/* 2^51 - 2^1 */ square(t0, z2_50_0);
/* 2^52 - 2^2 */ square(t1, t0);
/* 2^100 - 2^50 */
for (i = 2; i < 50; i += 2) {
square(t0, t1);
square(t1, t0);
}
/* 2^100 - 2^0 */ mult(z2_100_0, t1, z2_50_0);
/* 2^101 - 2^1 */ square(t1, z2_100_0);
/* 2^102 - 2^2 */ square(t0, t1);
/* 2^200 - 2^100 */
for (i = 2; i < 100; i += 2) {
square(t1, t0);
square(t0, t1);
}
/* 2^200 - 2^0 */ mult(t1, t0, z2_100_0);
/* 2^201 - 2^1 */ square(t0, t1);
/* 2^202 - 2^2 */ square(t1, t0);
/* 2^250 - 2^50 */
for (i = 2; i < 50; i += 2) {
square(t0, t1);
square(t1, t0);
}
/* 2^250 - 2^0 */ mult(t0, t1, z2_50_0);
/* 2^251 - 2^1 */ square(t1, t0);
/* 2^252 - 2^2 */ square(t0, t1);
/* 2^253 - 2^3 */ square(t1, t0);
/* 2^254 - 2^4 */ square(t0, t1);
/* 2^255 - 2^5 */ square(t1, t0);
/* 2^255 - 21 */ mult(out, t1, z11);
}
/*
* Computes q = Curve25519(p, s)
*/
SECStatus
ec_Curve25519_mul(PRUint8 *q, const PRUint8 *s, const PRUint8 *p)
{
elem point = { 0 };
elem x_2 = { 0 };
elem z_2 = { 0 };
elem X = { 0 };
elem scalar = { 0 };
PRUint32 i;
/* read and mask scalar */
for (i = 0; i < 32; ++i) {
scalar[i] = s[i];
}
scalar[0] &= 0xF8;
scalar[31] &= 0x7F;
scalar[31] |= 64;
/* read and mask point */
for (i = 0; i < 32; ++i) {
point[i] = p[i];
}
point[31] &= 0x7F;
monty(x_2, z_2, point, scalar);
recip(z_2, z_2);
mult(X, x_2, z_2);
reduce(X);
for (i = 0; i < 32; ++i) {
q[i] = X[i];
}
return 0;
}