ref: 8bc69a872883224675a55db51ac8f60ab5ed9e5a
dir: /third_party/boringssl/src/crypto/evp/p_x25519_asn1.c/
/* Copyright (c) 2019, Google Inc.
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
#include <openssl/evp.h>
#include <openssl/bytestring.h>
#include <openssl/curve25519.h>
#include <openssl/err.h>
#include <openssl/mem.h>
#include "internal.h"
#include "../internal.h"
static void x25519_free(EVP_PKEY *pkey) {
OPENSSL_free(pkey->pkey.ptr);
pkey->pkey.ptr = NULL;
}
static int x25519_set_priv_raw(EVP_PKEY *pkey, const uint8_t *in, size_t len) {
if (len != 32) {
OPENSSL_PUT_ERROR(EVP, EVP_R_DECODE_ERROR);
return 0;
}
X25519_KEY *key = OPENSSL_malloc(sizeof(X25519_KEY));
if (key == NULL) {
OPENSSL_PUT_ERROR(EVP, ERR_R_MALLOC_FAILURE);
return 0;
}
OPENSSL_memcpy(key->priv, in, 32);
X25519_public_from_private(key->pub, key->priv);
key->has_private = 1;
x25519_free(pkey);
pkey->pkey.ptr = key;
return 1;
}
static int x25519_set_pub_raw(EVP_PKEY *pkey, const uint8_t *in, size_t len) {
if (len != 32) {
OPENSSL_PUT_ERROR(EVP, EVP_R_DECODE_ERROR);
return 0;
}
X25519_KEY *key = OPENSSL_malloc(sizeof(X25519_KEY));
if (key == NULL) {
OPENSSL_PUT_ERROR(EVP, ERR_R_MALLOC_FAILURE);
return 0;
}
OPENSSL_memcpy(key->pub, in, 32);
key->has_private = 0;
x25519_free(pkey);
pkey->pkey.ptr = key;
return 1;
}
static int x25519_get_priv_raw(const EVP_PKEY *pkey, uint8_t *out,
size_t *out_len) {
const X25519_KEY *key = pkey->pkey.ptr;
if (!key->has_private) {
OPENSSL_PUT_ERROR(EVP, EVP_R_NOT_A_PRIVATE_KEY);
return 0;
}
if (out == NULL) {
*out_len = 32;
return 1;
}
if (*out_len < 32) {
OPENSSL_PUT_ERROR(EVP, EVP_R_BUFFER_TOO_SMALL);
return 0;
}
OPENSSL_memcpy(out, key->priv, 32);
*out_len = 32;
return 1;
}
static int x25519_get_pub_raw(const EVP_PKEY *pkey, uint8_t *out,
size_t *out_len) {
const X25519_KEY *key = pkey->pkey.ptr;
if (out == NULL) {
*out_len = 32;
return 1;
}
if (*out_len < 32) {
OPENSSL_PUT_ERROR(EVP, EVP_R_BUFFER_TOO_SMALL);
return 0;
}
OPENSSL_memcpy(out, key->pub, 32);
*out_len = 32;
return 1;
}
static int x25519_pub_decode(EVP_PKEY *out, CBS *params, CBS *key) {
// See RFC 8410, section 4.
// The parameters must be omitted. Public keys have length 32.
if (CBS_len(params) != 0) {
OPENSSL_PUT_ERROR(EVP, EVP_R_DECODE_ERROR);
return 0;
}
return x25519_set_pub_raw(out, CBS_data(key), CBS_len(key));
}
static int x25519_pub_encode(CBB *out, const EVP_PKEY *pkey) {
const X25519_KEY *key = pkey->pkey.ptr;
// See RFC 8410, section 4.
CBB spki, algorithm, oid, key_bitstring;
if (!CBB_add_asn1(out, &spki, CBS_ASN1_SEQUENCE) ||
!CBB_add_asn1(&spki, &algorithm, CBS_ASN1_SEQUENCE) ||
!CBB_add_asn1(&algorithm, &oid, CBS_ASN1_OBJECT) ||
!CBB_add_bytes(&oid, x25519_asn1_meth.oid, x25519_asn1_meth.oid_len) ||
!CBB_add_asn1(&spki, &key_bitstring, CBS_ASN1_BITSTRING) ||
!CBB_add_u8(&key_bitstring, 0 /* padding */) ||
!CBB_add_bytes(&key_bitstring, key->pub, 32) ||
!CBB_flush(out)) {
OPENSSL_PUT_ERROR(EVP, EVP_R_ENCODE_ERROR);
return 0;
}
return 1;
}
static int x25519_pub_cmp(const EVP_PKEY *a, const EVP_PKEY *b) {
const X25519_KEY *a_key = a->pkey.ptr;
const X25519_KEY *b_key = b->pkey.ptr;
return OPENSSL_memcmp(a_key->pub, b_key->pub, 32) == 0;
}
static int x25519_priv_decode(EVP_PKEY *out, CBS *params, CBS *key) {
// See RFC 8410, section 7.
// Parameters must be empty. The key is a 32-byte value wrapped in an extra
// OCTET STRING layer.
CBS inner;
if (CBS_len(params) != 0 ||
!CBS_get_asn1(key, &inner, CBS_ASN1_OCTETSTRING) ||
CBS_len(key) != 0) {
OPENSSL_PUT_ERROR(EVP, EVP_R_DECODE_ERROR);
return 0;
}
return x25519_set_priv_raw(out, CBS_data(&inner), CBS_len(&inner));
}
static int x25519_priv_encode(CBB *out, const EVP_PKEY *pkey) {
X25519_KEY *key = pkey->pkey.ptr;
if (!key->has_private) {
OPENSSL_PUT_ERROR(EVP, EVP_R_NOT_A_PRIVATE_KEY);
return 0;
}
// See RFC 8410, section 7.
CBB pkcs8, algorithm, oid, private_key, inner;
if (!CBB_add_asn1(out, &pkcs8, CBS_ASN1_SEQUENCE) ||
!CBB_add_asn1_uint64(&pkcs8, 0 /* version */) ||
!CBB_add_asn1(&pkcs8, &algorithm, CBS_ASN1_SEQUENCE) ||
!CBB_add_asn1(&algorithm, &oid, CBS_ASN1_OBJECT) ||
!CBB_add_bytes(&oid, x25519_asn1_meth.oid, x25519_asn1_meth.oid_len) ||
!CBB_add_asn1(&pkcs8, &private_key, CBS_ASN1_OCTETSTRING) ||
!CBB_add_asn1(&private_key, &inner, CBS_ASN1_OCTETSTRING) ||
// The PKCS#8 encoding stores only the 32-byte seed which is the first 32
// bytes of the private key.
!CBB_add_bytes(&inner, key->priv, 32) ||
!CBB_flush(out)) {
OPENSSL_PUT_ERROR(EVP, EVP_R_ENCODE_ERROR);
return 0;
}
return 1;
}
static int x25519_size(const EVP_PKEY *pkey) { return 32; }
static int x25519_bits(const EVP_PKEY *pkey) { return 253; }
const EVP_PKEY_ASN1_METHOD x25519_asn1_meth = {
EVP_PKEY_X25519,
{0x2b, 0x65, 0x6e},
3,
x25519_pub_decode,
x25519_pub_encode,
x25519_pub_cmp,
x25519_priv_decode,
x25519_priv_encode,
x25519_set_priv_raw,
x25519_set_pub_raw,
x25519_get_priv_raw,
x25519_get_pub_raw,
NULL /* pkey_opaque */,
x25519_size,
x25519_bits,
NULL /* param_missing */,
NULL /* param_copy */,
NULL /* param_cmp */,
x25519_free,
};
int EVP_PKEY_set1_tls_encodedpoint(EVP_PKEY *pkey, const uint8_t *in,
size_t len) {
// TODO(davidben): In OpenSSL, this function also works for |EVP_PKEY_EC|
// keys. Add support if it ever comes up.
if (pkey->type != EVP_PKEY_X25519) {
OPENSSL_PUT_ERROR(EVP, EVP_R_UNSUPPORTED_PUBLIC_KEY_TYPE);
return 0;
}
return x25519_set_pub_raw(pkey, in, len);
}
size_t EVP_PKEY_get1_tls_encodedpoint(const EVP_PKEY *pkey, uint8_t **out_ptr) {
// TODO(davidben): In OpenSSL, this function also works for |EVP_PKEY_EC|
// keys. Add support if it ever comes up.
if (pkey->type != EVP_PKEY_X25519) {
OPENSSL_PUT_ERROR(EVP, EVP_R_UNSUPPORTED_PUBLIC_KEY_TYPE);
return 0;
}
const X25519_KEY *key = pkey->pkey.ptr;
if (key == NULL) {
OPENSSL_PUT_ERROR(EVP, EVP_R_NO_KEY_SET);
return 0;
}
*out_ptr = OPENSSL_memdup(key->pub, 32);
return *out_ptr == NULL ? 0 : 32;
}