+++ /dev/null
-/*
- * Copyright 2016 The OpenSSL Project Authors. All Rights Reserved.
- *
- * Licensed under the OpenSSL license (the "License"). You may not use
- * this file except in compliance with the License. You can obtain a copy
- * in the file LICENSE in the source distribution or at
- * https://www.openssl.org/source/license.html
- */
-
-#include <string.h>
-#include <openssl/err.h>
-#include <openssl/rand.h>
-#include "ec_lcl.h"
-
-/* Length of Curve 25519 keys */
-#define EC_X25519_KEYLEN 32
-/* Group degree and order bits */
-#define EC_X25519_BITS 253
-
-/* Copy Curve25519 public key buffer, allocating is necessary */
-static int x25519_init_public(EC_POINT *pub, const void *src)
-{
- if (pub->custom_data == NULL) {
- pub->custom_data = OPENSSL_malloc(EC_X25519_KEYLEN);
- if (pub->custom_data == NULL)
- return 0;
- }
- if (src != NULL)
- memcpy(pub->custom_data, src, EC_X25519_KEYLEN);
- return 1;
-}
-
-/* Copy Curve25519 private key buffer, allocating is necessary */
-static int x25519_init_private(EC_KEY *dst, const void *src)
-{
- if (dst->custom_data == NULL) {
- dst->custom_data = OPENSSL_secure_malloc(EC_X25519_KEYLEN);
- if (dst->custom_data == NULL)
- return 0;
- }
- if (src != NULL)
- memcpy(dst->custom_data, src, EC_X25519_KEYLEN);
- return 1;
-}
-
-static int x25519_group_init(EC_GROUP *grp)
-{
- return 1;
-}
-
-static int x25519_group_copy(EC_GROUP *dst, const EC_GROUP *src)
-{
- return 1;
-}
-
-static int x25519_group_get_degree(const EC_GROUP *src)
-{
- return EC_X25519_BITS;
-}
-
-static int x25519_group_order_bits(const EC_GROUP *src)
-{
- return EC_X25519_BITS;
-}
-
-static int x25519_set_private(EC_KEY *eckey, const BIGNUM *priv_key)
-{
- if (BN_num_bytes(priv_key) > EC_X25519_KEYLEN)
- return 0;
- if (x25519_init_private(eckey, NULL))
- return 0;
- /* Convert BIGNUM form private key to internal format */
- if (BN_bn2lebinpad(priv_key, eckey->custom_data, EC_X25519_KEYLEN)
- != EC_X25519_KEYLEN)
- return 0;
- return 1;
-}
-
-static int x25519_keycheck(const EC_KEY *eckey)
-{
- const char *pubkey;
- if (eckey->pub_key == NULL)
- return 0;
- pubkey = eckey->pub_key->custom_data;
- if (pubkey == NULL)
- return 0;
- if (eckey->custom_data != NULL) {
- uint8_t tmp[EC_X25519_KEYLEN];
- /* Check eckey->priv_key exists and matches eckey->custom_data */
- if (eckey->priv_key == NULL)
- return 0;
- if (BN_bn2lebinpad(eckey->priv_key, tmp, EC_X25519_KEYLEN)
- != EC_X25519_KEYLEN
- || CRYPTO_memcmp(tmp, eckey->custom_data,
- EC_X25519_KEYLEN) != 0) {
- OPENSSL_cleanse(tmp, EC_X25519_KEYLEN);
- return 0;
- }
- X25519_public_from_private(tmp, eckey->custom_data);
- if (CRYPTO_memcmp(pubkey, tmp, EC_X25519_KEYLEN) == 0)
- return 1;
- return 0;
- } else {
- return 1;
- }
-}
-
-static int x25519_keygenpub(EC_KEY *eckey)
-{
- X25519_public_from_private(eckey->pub_key->custom_data,
- eckey->custom_data);
- return 1;
-}
-
-static int x25519_keygen(EC_KEY *eckey)
-{
- unsigned char *key;
- if (x25519_init_private(eckey, NULL) == 0)
- return 0;
- key = eckey->custom_data;
- if (RAND_bytes(key, EC_X25519_KEYLEN) <= 0)
- return 0;
- key[0] &= 248;
- key[31] &= 127;
- key[31] |= 64;
- /*
- * Although the private key is kept as an array in eckey->custom_data
- * Set eckey->priv_key too so existing code which uses
- * EC_KEY_get0_private_key() still works.
- */
- if (eckey->priv_key == NULL)
- eckey->priv_key = BN_secure_new();
- if (eckey->priv_key == NULL)
- return 0;
- if (BN_lebin2bn(eckey->custom_data, EC_X25519_KEYLEN, eckey->priv_key) ==
- NULL)
- return 0;
- if (eckey->pub_key == NULL)
- eckey->pub_key = EC_POINT_new(eckey->group);
- if (eckey->pub_key == NULL)
- return 0;
- return x25519_keygenpub(eckey);
-}
-
-static void x25519_keyfinish(EC_KEY *eckey)
-{
- OPENSSL_secure_free(eckey->custom_data);
- eckey->custom_data = NULL;
-}
-
-static int x25519_keycopy(EC_KEY *dest, const EC_KEY *src)
-{
- if (src->custom_data == NULL)
- return 0;
- return x25519_init_private(dest, src->custom_data);
-}
-
-static int x25519_oct2priv(EC_KEY *eckey, const unsigned char *buf, size_t len)
-{
- if (len != EC_X25519_KEYLEN)
- return 0;
- if (x25519_init_private(eckey, buf) == 0)
- return 0;
- /*
- * Although the private key is kept as an array in eckey->custom_data
- * Set eckey->priv_key too so existing code which uses
- * EC_KEY_get0_private_key() still works.
- */
- if (eckey->priv_key == NULL)
- eckey->priv_key = BN_secure_new();
- if (eckey->priv_key == NULL)
- return 0;
- if (BN_lebin2bn(buf, EC_X25519_KEYLEN, eckey->priv_key) == NULL)
- return 0;
- return 1;
-}
-
-static size_t x25519_priv2oct(const EC_KEY *eckey,
- unsigned char *buf, size_t len)
-{
- size_t keylen = EC_X25519_KEYLEN;
- if (eckey->custom_data == NULL)
- return 0;
- if (buf != NULL) {
- if (len < keylen)
- return 0;
- memcpy(buf, eckey->custom_data, keylen);
- }
- return keylen;
-}
-
-static int x25519_point_init(EC_POINT *pt)
-{
- return x25519_init_public(pt, NULL);
-}
-
-static void x25519_point_finish(EC_POINT *pt)
-{
- OPENSSL_free(pt->custom_data);
- pt->custom_data = NULL;
-}
-
-static void x25519_point_clear_finish(EC_POINT *pt)
-{
- OPENSSL_clear_free(pt->custom_data, EC_X25519_KEYLEN);
- pt->custom_data = NULL;
-}
-
-static int x25519_point_copy(EC_POINT *dst, const EC_POINT *src)
-{
- memcpy(dst->custom_data, src->custom_data, EC_X25519_KEYLEN);
- return 1;
-}
-
-static size_t x25519_point2oct(const EC_GROUP *grp, const EC_POINT *pt,
- point_conversion_form_t form,
- unsigned char *buf, size_t len, BN_CTX *ctx)
-{
- if (buf != NULL) {
- if (len < EC_X25519_KEYLEN)
- return 0;
- memcpy(buf, pt->custom_data, EC_X25519_KEYLEN);
- }
- return EC_X25519_KEYLEN;
-}
-
-static int x25519_oct2point(const EC_GROUP *grp, EC_POINT *pt,
- const unsigned char *buf, size_t len, BN_CTX *ctx)
-{
- unsigned char *pubkey = pt->custom_data;
- if (len != EC_X25519_KEYLEN)
- return 0;
- memcpy(pubkey, buf, EC_X25519_KEYLEN);
- /* Mask off MSB */
- pubkey[EC_X25519_KEYLEN - 1] &= 0x7F;
- return 1;
-}
-
-static int x25519_point_cmp(const EC_GROUP *group, const EC_POINT *a,
- const EC_POINT *b, BN_CTX *ctx)
-{
- /* Shouldn't happen as initialised to non-zero */
- if (a->custom_data == NULL || b->custom_data == NULL)
- return -1;
-
- if (CRYPTO_memcmp(a->custom_data, b->custom_data, EC_X25519_KEYLEN) == 0)
- return 0;
-
- return 1;
-}
-
-static int x25519_compute_key(unsigned char **psec, size_t *pseclen,
- const EC_POINT *pub_key, const EC_KEY *ecdh)
-{
- unsigned char *key;
- int ret = 0;
- if (ecdh->custom_data == NULL)
- return 0;
- key = OPENSSL_malloc(EC_X25519_KEYLEN);
- if (key == NULL)
- return 0;
- if (X25519(key, ecdh->custom_data, pub_key->custom_data) == 0)
- goto err;
- *psec = key;
- *pseclen = EC_X25519_KEYLEN;
- return 1;
-
- err:
- OPENSSL_clear_free(key, EC_X25519_KEYLEN);
- return ret;
-}
-
-const EC_METHOD *ec_x25519_meth(void)
-{
- static const EC_METHOD ret = {
- EC_FLAGS_CUSTOM_CURVE | EC_FLAGS_NO_SIGN,
- NID_undef,
- x25519_group_init, /* group_init */
- 0, /* group_finish */
- 0, /* group_clear_finish */
- x25519_group_copy, /* group_copy */
- 0, /* group_set_curve */
- 0, /* group_get_curve */
- x25519_group_get_degree,
- x25519_group_order_bits,
- 0, /* group_check_discriminant */
- x25519_point_init,
- x25519_point_finish,
- x25519_point_clear_finish,
- x25519_point_copy,
- 0, /* point_set_to_infinity */
- 0, /* set_Jprojective_coordinates_GFp */
- 0, /* get_Jprojective_coordinates_GFp */
- 0, /* point_set_affine_coordinates */
- 0, /* point_get_affine_coordinates */
- 0, /* point_set_compressed_coordinates */
- x25519_point2oct,
- x25519_oct2point,
- 0, /* simple_add */
- 0, /* simple_dbl */
- 0, /* simple_invert */
- 0, /* simple_is_at_infinity */
- 0, /* simple_is_on_curve */
- x25519_point_cmp,
- 0, /* simple_make_affine */
- 0, /* simple_points_make_affine */
- 0, /* points_mul */
- 0, /* precompute_mult */
- 0, /* have_precompute_mult */
- 0, /* field_mul */
- 0, /* field_sqr */
- 0, /* field_div */
- 0, /* field_encode */
- 0, /* field_decode */
- 0, /* field_set_to_one */
- x25519_priv2oct,
- x25519_oct2priv,
- x25519_set_private,
- x25519_keygen,
- x25519_keycheck,
- x25519_keygenpub,
- x25519_keycopy,
- x25519_keyfinish,
- x25519_compute_key
- };
-
- return &ret;
-}
projects / openssl.git / blobdiff