--- /dev/null
+/*
+ * Copyright 2006-2016 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 <stdio.h>
+#include "internal/cryptlib.h"
+#include <openssl/x509.h>
+#include <openssl/ec.h>
+#include <openssl/rand.h>
+#include "internal/asn1_int.h"
+#include "internal/evp_int.h"
+#include "ec_lcl.h"
+
+#define X25519_KEYLEN 32
+#define X25519_BITS 253
+#define X25519_SECURITY_BITS 128
+
+typedef struct {
+ unsigned char pubkey[X25519_KEYLEN];
+ unsigned char *privkey;
+} X25519_KEY;
+
+typedef enum {
+ X25519_PUBLIC,
+ X25519_PRIVATE,
+ X25519_KEYGEN
+} ecx_key_op_t;
+
+/* Setup EVP_PKEY using public, private or generation */
+static int ecx_key_op(EVP_PKEY *pkey, X509_ALGOR *palg,
+ const unsigned char *p, int plen, ecx_key_op_t op)
+{
+ int ptype;
+ X25519_KEY *xkey = NULL;
+
+ if (op != X25519_KEYGEN) {
+ /* Algorithm parameters must be absent */
+ X509_ALGOR_get0(NULL, &ptype, NULL, palg);
+ if (ptype != V_ASN1_UNDEF) {
+ ECerr(EC_F_ECX_KEY_OP, EC_R_INVALID_ENCODING);
+ return 0;
+ }
+
+ if (p == NULL || plen != X25519_KEYLEN) {
+ ECerr(EC_F_ECX_KEY_OP, EC_R_INVALID_ENCODING);
+ return 0;
+ }
+ }
+
+ xkey = OPENSSL_zalloc(sizeof(*xkey));
+ if (xkey == NULL) {
+ ECerr(EC_F_ECX_KEY_OP, ERR_R_MALLOC_FAILURE);
+ return 0;
+ }
+
+ if (op == X25519_PUBLIC) {
+ memcpy(xkey->pubkey, p, plen);
+ } else {
+ xkey->privkey = OPENSSL_secure_malloc(X25519_KEYLEN);
+ if (xkey->privkey == NULL) {
+ ECerr(EC_F_ECX_KEY_OP, ERR_R_MALLOC_FAILURE);
+ OPENSSL_free(xkey);
+ return 0;
+ }
+ if (op == X25519_KEYGEN) {
+ if (RAND_bytes(xkey->privkey, X25519_KEYLEN) <= 0) {
+ OPENSSL_secure_free(xkey->privkey);
+ OPENSSL_free(xkey);
+ return 0;
+ }
+ xkey->privkey[0] &= 248;
+ xkey->privkey[31] &= 127;
+ xkey->privkey[31] |= 64;
+ } else {
+ memcpy(xkey->privkey, p, X25519_KEYLEN);
+ }
+ X25519_public_from_private(xkey->pubkey, xkey->privkey);
+ }
+
+ EVP_PKEY_assign(pkey, NID_X25519, xkey);
+ return 1;
+}
+
+static int ecx_pub_encode(X509_PUBKEY *pk, const EVP_PKEY *pkey)
+{
+ const X25519_KEY *xkey = pkey->pkey.ptr;
+ unsigned char *penc;
+
+ if (xkey == NULL) {
+ ECerr(EC_F_ECX_PUB_ENCODE, EC_R_INVALID_KEY);
+ return 0;
+ }
+
+ penc = OPENSSL_memdup(xkey->pubkey, X25519_KEYLEN);
+ if (penc == NULL) {
+ ECerr(EC_F_ECX_PUB_ENCODE, ERR_R_MALLOC_FAILURE);
+ return 0;
+ }
+
+ if (!X509_PUBKEY_set0_param(pk, OBJ_nid2obj(NID_X25519), V_ASN1_UNDEF,
+ NULL, penc, X25519_KEYLEN)) {
+ OPENSSL_free(penc);
+ ECerr(EC_F_ECX_PUB_ENCODE, ERR_R_MALLOC_FAILURE);
+ return 0;
+ }
+ return 1;
+}
+
+static int ecx_pub_decode(EVP_PKEY *pkey, X509_PUBKEY *pubkey)
+{
+ const unsigned char *p;
+ int pklen;
+ X509_ALGOR *palg;
+
+ if (!X509_PUBKEY_get0_param(NULL, &p, &pklen, &palg, pubkey))
+ return 0;
+ return ecx_key_op(pkey, palg, p, pklen, X25519_PUBLIC);
+}
+
+static int ecx_pub_cmp(const EVP_PKEY *a, const EVP_PKEY *b)
+{
+ const X25519_KEY *akey = a->pkey.ptr;
+ const X25519_KEY *bkey = b->pkey.ptr;
+
+ if (akey == NULL || bkey == NULL)
+ return -2;
+ return !CRYPTO_memcmp(akey->pubkey, bkey->pubkey, X25519_KEYLEN);
+}
+
+static int ecx_priv_decode(EVP_PKEY *pkey, PKCS8_PRIV_KEY_INFO *p8)
+{
+ const unsigned char *p;
+ int plen;
+ ASN1_OCTET_STRING *oct = NULL;
+ X509_ALGOR *palg;
+ int rv;
+
+ if (!PKCS8_pkey_get0(NULL, &p, &plen, &palg, p8))
+ return 0;
+
+ oct = d2i_ASN1_OCTET_STRING(NULL, &p, plen);
+ if (oct == NULL) {
+ p = NULL;
+ plen = 0;
+ } else {
+ p = ASN1_STRING_data(oct);
+ plen = ASN1_STRING_length(oct);
+ }
+
+ rv = ecx_key_op(pkey, palg, p, plen, X25519_PRIVATE);
+ ASN1_OCTET_STRING_free(oct);
+ return rv;
+}
+
+static int ecx_priv_encode(PKCS8_PRIV_KEY_INFO *p8, const EVP_PKEY *pkey)
+{
+ const X25519_KEY *xkey = pkey->pkey.ptr;
+ ASN1_OCTET_STRING oct;
+ unsigned char *penc = NULL;
+ int penclen;
+
+ if (xkey == NULL || xkey->privkey == NULL) {
+ ECerr(EC_F_ECX_PRIV_ENCODE, EC_R_INVALID_PRIVATE_KEY);
+ return 0;
+ }
+
+ oct.data = xkey->privkey;
+ oct.length = X25519_KEYLEN;
+ oct.flags = 0;
+
+ penclen = i2d_ASN1_OCTET_STRING(&oct, &penc);
+ if (penclen < 0) {
+ ECerr(EC_F_ECX_PRIV_ENCODE, ERR_R_MALLOC_FAILURE);
+ return 0;
+ }
+
+ if (!PKCS8_pkey_set0(p8, OBJ_nid2obj(NID_X25519), 0,
+ V_ASN1_UNDEF, NULL, penc, penclen)) {
+ OPENSSL_clear_free(penc, penclen);
+ ECerr(EC_F_ECX_PRIV_ENCODE, ERR_R_MALLOC_FAILURE);
+ return 0;
+ }
+
+ return 1;
+}
+
+static int ecx_size(const EVP_PKEY *pkey)
+{
+ return X25519_KEYLEN;
+}
+
+static int ecx_bits(const EVP_PKEY *pkey)
+{
+ return X25519_BITS;
+}
+
+static int ecx_security_bits(const EVP_PKEY *pkey)
+{
+ return X25519_SECURITY_BITS;
+}
+
+static void ecx_free(EVP_PKEY *pkey)
+{
+ X25519_KEY *xkey = pkey->pkey.ptr;
+
+ if (xkey)
+ OPENSSL_secure_free(xkey->privkey);
+ OPENSSL_free(xkey);
+}
+
+/* "parameters" are always equal */
+static int ecx_cmp_parameters(const EVP_PKEY *a, const EVP_PKEY *b)
+{
+ return 1;
+}
+
+static int ecx_key_print(BIO *bp, const EVP_PKEY *pkey, int indent,
+ ASN1_PCTX *ctx, ecx_key_op_t op)
+{
+ const X25519_KEY *xkey = pkey->pkey.ptr;
+
+ if (op == X25519_PRIVATE) {
+ if (xkey == NULL || xkey->privkey == NULL) {
+ if (BIO_printf(bp, "%*s<INVALID PRIVATE KEY>\n", indent, "") <= 0)
+ return 0;
+ return 1;
+ }
+ if (BIO_printf(bp, "%*sX25519 Private-Key:\n", indent, "") <= 0)
+ return 0;
+ if (BIO_printf(bp, "%*spriv:\n", indent, "") <= 0)
+ return 0;
+ if (ASN1_buf_print(bp, xkey->privkey, X25519_KEYLEN, indent + 4) == 0)
+ return 0;
+ } else {
+ if (xkey == NULL) {
+ if (BIO_printf(bp, "%*s<INVALID PUBLIC KEY>\n", indent, "") <= 0)
+ return 0;
+ return 1;
+ }
+ if (BIO_printf(bp, "%*sX25519 Public-Key:\n", indent, "") <= 0)
+ return 0;
+ }
+ if (BIO_printf(bp, "%*spub:\n", indent, "") <= 0)
+ return 0;
+ if (ASN1_buf_print(bp, xkey->pubkey, X25519_KEYLEN, indent + 4) == 0)
+ return 0;
+ return 1;
+}
+
+static int ecx_priv_print(BIO *bp, const EVP_PKEY *pkey, int indent,
+ ASN1_PCTX *ctx)
+{
+ return ecx_key_print(bp, pkey, indent, ctx, X25519_PRIVATE);
+}
+
+static int ecx_pub_print(BIO *bp, const EVP_PKEY *pkey, int indent,
+ ASN1_PCTX *ctx)
+{
+ return ecx_key_print(bp, pkey, indent, ctx, X25519_PUBLIC);
+}
+
+static int ecx_ctrl(EVP_PKEY *pkey, int op, long arg1, void *arg2)
+{
+ return -2;
+}
+
+const EVP_PKEY_ASN1_METHOD ecx25519_asn1_meth = {
+ NID_X25519,
+ NID_X25519,
+ 0,
+ "X25519",
+ "OpenSSL X25519 algorithm",
+
+ ecx_pub_decode,
+ ecx_pub_encode,
+ ecx_pub_cmp,
+ ecx_pub_print,
+
+ ecx_priv_decode,
+ ecx_priv_encode,
+ ecx_priv_print,
+
+ ecx_size,
+ ecx_bits,
+ ecx_security_bits,
+
+ 0, 0, 0, 0,
+ ecx_cmp_parameters,
+ 0, 0,
+
+ ecx_free,
+ ecx_ctrl,
+ NULL,
+ NULL
+};
+
+static int pkey_ecx_keygen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey)
+{
+ return ecx_key_op(pkey, NULL, NULL, 0, X25519_KEYGEN);
+}
+
+static int pkey_ecx_derive(EVP_PKEY_CTX *ctx, unsigned char *key,
+ size_t *keylen)
+{
+ const X25519_KEY *pkey, *peerkey;
+
+ if (ctx->pkey == NULL || ctx->peerkey == NULL) {
+ ECerr(EC_F_PKEY_ECX_DERIVE, EC_R_KEYS_NOT_SET);
+ return 0;
+ }
+ pkey = ctx->pkey->pkey.ptr;
+ peerkey = ctx->peerkey->pkey.ptr;
+ if (pkey == NULL || pkey->privkey == NULL) {
+ ECerr(EC_F_PKEY_ECX_DERIVE, EC_R_INVALID_PRIVATE_KEY);
+ return 0;
+ }
+ if (peerkey == NULL) {
+ ECerr(EC_F_PKEY_ECX_DERIVE, EC_R_INVALID_PEER_KEY);
+ return 0;
+ }
+ *keylen = X25519_KEYLEN;
+ if (key != NULL && X25519(key, pkey->privkey, peerkey->pubkey) == 0)
+ return 0;
+ return 1;
+}
+
+static int pkey_ecx_ctrl(EVP_PKEY_CTX *ctx, int type, int p1, void *p2)
+{
+ /* Only need to handle peer key for derivation */
+ if (type == EVP_PKEY_CTRL_PEER_KEY)
+ return 1;
+ return -2;
+}
+
+const EVP_PKEY_METHOD ecx25519_pkey_meth = {
+ NID_X25519,
+ 0, 0, 0, 0, 0, 0, 0,
+ pkey_ecx_keygen,
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+ pkey_ecx_derive,
+ pkey_ecx_ctrl,
+ 0
+};
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