373 lines
9.3 KiB
C
373 lines
9.3 KiB
C
/*
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* Copyright 2006-2016 The OpenSSL Project Authors. All Rights Reserved.
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*
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* Licensed under the OpenSSL license (the "License"). You may not use
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* this file except in compliance with the License. You can obtain a copy
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* in the file LICENSE in the source distribution or at
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* https://www.openssl.org/source/license.html
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*/
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#include <stdio.h>
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#include "internal/cryptlib.h"
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#include <openssl/x509.h>
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#include <openssl/ec.h>
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#include <openssl/rand.h>
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#include "internal/asn1_int.h"
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#include "internal/evp_int.h"
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#include "ec_lcl.h"
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#define X25519_KEYLEN 32
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#define X25519_BITS 253
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#define X25519_SECURITY_BITS 128
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typedef struct {
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unsigned char pubkey[X25519_KEYLEN];
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unsigned char *privkey;
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} X25519_KEY;
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typedef enum {
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X25519_PUBLIC,
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X25519_PRIVATE,
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X25519_KEYGEN
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} ecx_key_op_t;
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/* Setup EVP_PKEY using public, private or generation */
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static int ecx_key_op(EVP_PKEY *pkey, const X509_ALGOR *palg,
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const unsigned char *p, int plen, ecx_key_op_t op)
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{
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X25519_KEY *xkey;
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if (op != X25519_KEYGEN) {
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if (palg != NULL) {
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int ptype;
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/* Algorithm parameters must be absent */
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X509_ALGOR_get0(NULL, &ptype, NULL, palg);
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if (ptype != V_ASN1_UNDEF) {
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ECerr(EC_F_ECX_KEY_OP, EC_R_INVALID_ENCODING);
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return 0;
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}
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}
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if (p == NULL || plen != X25519_KEYLEN) {
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ECerr(EC_F_ECX_KEY_OP, EC_R_INVALID_ENCODING);
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return 0;
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}
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}
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xkey = OPENSSL_zalloc(sizeof(*xkey));
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if (xkey == NULL) {
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ECerr(EC_F_ECX_KEY_OP, ERR_R_MALLOC_FAILURE);
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return 0;
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}
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if (op == X25519_PUBLIC) {
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memcpy(xkey->pubkey, p, plen);
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} else {
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xkey->privkey = OPENSSL_secure_malloc(X25519_KEYLEN);
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if (xkey->privkey == NULL) {
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ECerr(EC_F_ECX_KEY_OP, ERR_R_MALLOC_FAILURE);
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OPENSSL_free(xkey);
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return 0;
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}
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if (op == X25519_KEYGEN) {
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if (RAND_bytes(xkey->privkey, X25519_KEYLEN) <= 0) {
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OPENSSL_secure_free(xkey->privkey);
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OPENSSL_free(xkey);
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return 0;
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}
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xkey->privkey[0] &= 248;
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xkey->privkey[31] &= 127;
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xkey->privkey[31] |= 64;
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} else {
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memcpy(xkey->privkey, p, X25519_KEYLEN);
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}
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X25519_public_from_private(xkey->pubkey, xkey->privkey);
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}
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EVP_PKEY_assign(pkey, NID_X25519, xkey);
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return 1;
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}
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static int ecx_pub_encode(X509_PUBKEY *pk, const EVP_PKEY *pkey)
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{
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const X25519_KEY *xkey = pkey->pkey.ptr;
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unsigned char *penc;
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if (xkey == NULL) {
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ECerr(EC_F_ECX_PUB_ENCODE, EC_R_INVALID_KEY);
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return 0;
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}
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penc = OPENSSL_memdup(xkey->pubkey, X25519_KEYLEN);
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if (penc == NULL) {
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ECerr(EC_F_ECX_PUB_ENCODE, ERR_R_MALLOC_FAILURE);
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return 0;
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}
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if (!X509_PUBKEY_set0_param(pk, OBJ_nid2obj(NID_X25519), V_ASN1_UNDEF,
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NULL, penc, X25519_KEYLEN)) {
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OPENSSL_free(penc);
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ECerr(EC_F_ECX_PUB_ENCODE, ERR_R_MALLOC_FAILURE);
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return 0;
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}
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return 1;
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}
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static int ecx_pub_decode(EVP_PKEY *pkey, X509_PUBKEY *pubkey)
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{
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const unsigned char *p;
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int pklen;
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X509_ALGOR *palg;
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if (!X509_PUBKEY_get0_param(NULL, &p, &pklen, &palg, pubkey))
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return 0;
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return ecx_key_op(pkey, palg, p, pklen, X25519_PUBLIC);
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}
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static int ecx_pub_cmp(const EVP_PKEY *a, const EVP_PKEY *b)
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{
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const X25519_KEY *akey = a->pkey.ptr;
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const X25519_KEY *bkey = b->pkey.ptr;
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if (akey == NULL || bkey == NULL)
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return -2;
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return !CRYPTO_memcmp(akey->pubkey, bkey->pubkey, X25519_KEYLEN);
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}
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static int ecx_priv_decode(EVP_PKEY *pkey, const PKCS8_PRIV_KEY_INFO *p8)
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{
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const unsigned char *p;
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int plen;
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ASN1_OCTET_STRING *oct = NULL;
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const X509_ALGOR *palg;
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int rv;
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if (!PKCS8_pkey_get0(NULL, &p, &plen, &palg, p8))
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return 0;
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oct = d2i_ASN1_OCTET_STRING(NULL, &p, plen);
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if (oct == NULL) {
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p = NULL;
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plen = 0;
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} else {
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p = ASN1_STRING_get0_data(oct);
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plen = ASN1_STRING_length(oct);
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}
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rv = ecx_key_op(pkey, palg, p, plen, X25519_PRIVATE);
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ASN1_OCTET_STRING_free(oct);
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return rv;
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}
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static int ecx_priv_encode(PKCS8_PRIV_KEY_INFO *p8, const EVP_PKEY *pkey)
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{
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const X25519_KEY *xkey = pkey->pkey.ptr;
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ASN1_OCTET_STRING oct;
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unsigned char *penc = NULL;
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int penclen;
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if (xkey == NULL || xkey->privkey == NULL) {
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ECerr(EC_F_ECX_PRIV_ENCODE, EC_R_INVALID_PRIVATE_KEY);
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return 0;
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}
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oct.data = xkey->privkey;
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oct.length = X25519_KEYLEN;
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oct.flags = 0;
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penclen = i2d_ASN1_OCTET_STRING(&oct, &penc);
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if (penclen < 0) {
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ECerr(EC_F_ECX_PRIV_ENCODE, ERR_R_MALLOC_FAILURE);
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return 0;
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}
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if (!PKCS8_pkey_set0(p8, OBJ_nid2obj(NID_X25519), 0,
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V_ASN1_UNDEF, NULL, penc, penclen)) {
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OPENSSL_clear_free(penc, penclen);
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ECerr(EC_F_ECX_PRIV_ENCODE, ERR_R_MALLOC_FAILURE);
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return 0;
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}
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return 1;
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}
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static int ecx_size(const EVP_PKEY *pkey)
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{
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return X25519_KEYLEN;
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}
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static int ecx_bits(const EVP_PKEY *pkey)
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{
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return X25519_BITS;
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}
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static int ecx_security_bits(const EVP_PKEY *pkey)
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{
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return X25519_SECURITY_BITS;
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}
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static void ecx_free(EVP_PKEY *pkey)
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{
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X25519_KEY *xkey = pkey->pkey.ptr;
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if (xkey)
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OPENSSL_secure_free(xkey->privkey);
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OPENSSL_free(xkey);
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}
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/* "parameters" are always equal */
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static int ecx_cmp_parameters(const EVP_PKEY *a, const EVP_PKEY *b)
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{
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return 1;
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}
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static int ecx_key_print(BIO *bp, const EVP_PKEY *pkey, int indent,
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ASN1_PCTX *ctx, ecx_key_op_t op)
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{
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const X25519_KEY *xkey = pkey->pkey.ptr;
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if (op == X25519_PRIVATE) {
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if (xkey == NULL || xkey->privkey == NULL) {
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if (BIO_printf(bp, "%*s<INVALID PRIVATE KEY>\n", indent, "") <= 0)
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return 0;
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return 1;
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}
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if (BIO_printf(bp, "%*sX25519 Private-Key:\n", indent, "") <= 0)
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return 0;
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if (BIO_printf(bp, "%*spriv:\n", indent, "") <= 0)
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return 0;
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if (ASN1_buf_print(bp, xkey->privkey, X25519_KEYLEN, indent + 4) == 0)
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return 0;
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} else {
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if (xkey == NULL) {
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if (BIO_printf(bp, "%*s<INVALID PUBLIC KEY>\n", indent, "") <= 0)
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return 0;
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return 1;
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}
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if (BIO_printf(bp, "%*sX25519 Public-Key:\n", indent, "") <= 0)
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return 0;
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}
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if (BIO_printf(bp, "%*spub:\n", indent, "") <= 0)
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return 0;
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if (ASN1_buf_print(bp, xkey->pubkey, X25519_KEYLEN, indent + 4) == 0)
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return 0;
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return 1;
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}
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static int ecx_priv_print(BIO *bp, const EVP_PKEY *pkey, int indent,
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ASN1_PCTX *ctx)
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{
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return ecx_key_print(bp, pkey, indent, ctx, X25519_PRIVATE);
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}
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static int ecx_pub_print(BIO *bp, const EVP_PKEY *pkey, int indent,
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ASN1_PCTX *ctx)
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{
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return ecx_key_print(bp, pkey, indent, ctx, X25519_PUBLIC);
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}
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static int ecx_ctrl(EVP_PKEY *pkey, int op, long arg1, void *arg2)
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{
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switch (op) {
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case ASN1_PKEY_CTRL_SET1_TLS_ENCPT:
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return ecx_key_op(pkey, NULL, arg2, arg1, X25519_PUBLIC);
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case ASN1_PKEY_CTRL_GET1_TLS_ENCPT:
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if (pkey->pkey.ptr != NULL) {
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const X25519_KEY *xkey = pkey->pkey.ptr;
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unsigned char **ppt = arg2;
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*ppt = OPENSSL_memdup(xkey->pubkey, X25519_KEYLEN);
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if (*ppt != NULL)
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return X25519_KEYLEN;
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}
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return 0;
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case ASN1_PKEY_CTRL_DEFAULT_MD_NID:
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*(int *)arg2 = NID_sha256;
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return 2;
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default:
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return -2;
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}
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}
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const EVP_PKEY_ASN1_METHOD ecx25519_asn1_meth = {
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NID_X25519,
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NID_X25519,
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0,
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"X25519",
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"OpenSSL X25519 algorithm",
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ecx_pub_decode,
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ecx_pub_encode,
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ecx_pub_cmp,
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ecx_pub_print,
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ecx_priv_decode,
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ecx_priv_encode,
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ecx_priv_print,
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ecx_size,
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ecx_bits,
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ecx_security_bits,
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0, 0, 0, 0,
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ecx_cmp_parameters,
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0, 0,
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ecx_free,
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ecx_ctrl,
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NULL,
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NULL
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};
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static int pkey_ecx_keygen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey)
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{
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return ecx_key_op(pkey, NULL, NULL, 0, X25519_KEYGEN);
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}
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static int pkey_ecx_derive(EVP_PKEY_CTX *ctx, unsigned char *key,
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size_t *keylen)
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{
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const X25519_KEY *pkey, *peerkey;
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if (ctx->pkey == NULL || ctx->peerkey == NULL) {
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ECerr(EC_F_PKEY_ECX_DERIVE, EC_R_KEYS_NOT_SET);
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return 0;
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}
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pkey = ctx->pkey->pkey.ptr;
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peerkey = ctx->peerkey->pkey.ptr;
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if (pkey == NULL || pkey->privkey == NULL) {
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ECerr(EC_F_PKEY_ECX_DERIVE, EC_R_INVALID_PRIVATE_KEY);
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return 0;
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}
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if (peerkey == NULL) {
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ECerr(EC_F_PKEY_ECX_DERIVE, EC_R_INVALID_PEER_KEY);
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return 0;
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}
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*keylen = X25519_KEYLEN;
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if (key != NULL && X25519(key, pkey->privkey, peerkey->pubkey) == 0)
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return 0;
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return 1;
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}
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static int pkey_ecx_ctrl(EVP_PKEY_CTX *ctx, int type, int p1, void *p2)
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{
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/* Only need to handle peer key for derivation */
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if (type == EVP_PKEY_CTRL_PEER_KEY)
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return 1;
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return -2;
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}
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const EVP_PKEY_METHOD ecx25519_pkey_meth = {
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NID_X25519,
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0, 0, 0, 0, 0, 0, 0,
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pkey_ecx_keygen,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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pkey_ecx_derive,
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pkey_ecx_ctrl,
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0
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};
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