ref: ca70040abf8d8ab2cb03575f65131ad8ef8f12a1
dir: /third_party/boringssl/src/ssl/ssl_key_share.cc/
/* Copyright (c) 2015, 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/ssl.h>
#include <assert.h>
#include <string.h>
#include <utility>
#include <openssl/bn.h>
#include <openssl/bytestring.h>
#include <openssl/curve25519.h>
#include <openssl/ec.h>
#include <openssl/err.h>
#include <openssl/hrss.h>
#include <openssl/mem.h>
#include <openssl/nid.h>
#include <openssl/rand.h>
#include "internal.h"
#include "../crypto/internal.h"
BSSL_NAMESPACE_BEGIN
namespace {
class ECKeyShare : public SSLKeyShare {
public:
ECKeyShare(int nid, uint16_t group_id) : nid_(nid), group_id_(group_id) {}
uint16_t GroupID() const override { return group_id_; }
bool Offer(CBB *out) override {
assert(!private_key_);
// Set up a shared |BN_CTX| for all operations.
UniquePtr<BN_CTX> bn_ctx(BN_CTX_new());
if (!bn_ctx) {
return false;
}
BN_CTXScope scope(bn_ctx.get());
// Generate a private key.
UniquePtr<EC_GROUP> group(EC_GROUP_new_by_curve_name(nid_));
private_key_.reset(BN_new());
if (!group || !private_key_ ||
!BN_rand_range_ex(private_key_.get(), 1,
EC_GROUP_get0_order(group.get()))) {
return false;
}
// Compute the corresponding public key and serialize it.
UniquePtr<EC_POINT> public_key(EC_POINT_new(group.get()));
if (!public_key ||
!EC_POINT_mul(group.get(), public_key.get(), private_key_.get(), NULL,
NULL, bn_ctx.get()) ||
!EC_POINT_point2cbb(out, group.get(), public_key.get(),
POINT_CONVERSION_UNCOMPRESSED, bn_ctx.get())) {
return false;
}
return true;
}
bool Finish(Array<uint8_t> *out_secret, uint8_t *out_alert,
Span<const uint8_t> peer_key) override {
assert(private_key_);
*out_alert = SSL_AD_INTERNAL_ERROR;
// Set up a shared |BN_CTX| for all operations.
UniquePtr<BN_CTX> bn_ctx(BN_CTX_new());
if (!bn_ctx) {
return false;
}
BN_CTXScope scope(bn_ctx.get());
UniquePtr<EC_GROUP> group(EC_GROUP_new_by_curve_name(nid_));
if (!group) {
return false;
}
UniquePtr<EC_POINT> peer_point(EC_POINT_new(group.get()));
UniquePtr<EC_POINT> result(EC_POINT_new(group.get()));
BIGNUM *x = BN_CTX_get(bn_ctx.get());
if (!peer_point || !result || !x) {
return false;
}
if (peer_key.empty() || peer_key[0] != POINT_CONVERSION_UNCOMPRESSED ||
!EC_POINT_oct2point(group.get(), peer_point.get(), peer_key.data(),
peer_key.size(), bn_ctx.get())) {
OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_ECPOINT);
*out_alert = SSL_AD_DECODE_ERROR;
return false;
}
// Compute the x-coordinate of |peer_key| * |private_key_|.
if (!EC_POINT_mul(group.get(), result.get(), NULL, peer_point.get(),
private_key_.get(), bn_ctx.get()) ||
!EC_POINT_get_affine_coordinates_GFp(group.get(), result.get(), x, NULL,
bn_ctx.get())) {
return false;
}
// Encode the x-coordinate left-padded with zeros.
Array<uint8_t> secret;
if (!secret.Init((EC_GROUP_get_degree(group.get()) + 7) / 8) ||
!BN_bn2bin_padded(secret.data(), secret.size(), x)) {
return false;
}
*out_secret = std::move(secret);
return true;
}
bool SerializePrivateKey(CBB *out) override {
assert(private_key_);
UniquePtr<EC_GROUP> group(EC_GROUP_new_by_curve_name(nid_));
// Padding is added to avoid leaking the length.
size_t len = BN_num_bytes(EC_GROUP_get0_order(group.get()));
return BN_bn2cbb_padded(out, len, private_key_.get());
}
bool DeserializePrivateKey(CBS *in) override {
assert(!private_key_);
private_key_.reset(BN_bin2bn(CBS_data(in), CBS_len(in), nullptr));
return private_key_ != nullptr;
}
private:
UniquePtr<BIGNUM> private_key_;
int nid_;
uint16_t group_id_;
};
class X25519KeyShare : public SSLKeyShare {
public:
X25519KeyShare() {}
uint16_t GroupID() const override { return SSL_CURVE_X25519; }
bool Offer(CBB *out) override {
uint8_t public_key[32];
X25519_keypair(public_key, private_key_);
return !!CBB_add_bytes(out, public_key, sizeof(public_key));
}
bool Finish(Array<uint8_t> *out_secret, uint8_t *out_alert,
Span<const uint8_t> peer_key) override {
*out_alert = SSL_AD_INTERNAL_ERROR;
Array<uint8_t> secret;
if (!secret.Init(32)) {
OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
return false;
}
if (peer_key.size() != 32 ||
!X25519(secret.data(), private_key_, peer_key.data())) {
*out_alert = SSL_AD_DECODE_ERROR;
OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_ECPOINT);
return false;
}
*out_secret = std::move(secret);
return true;
}
bool SerializePrivateKey(CBB *out) override {
return CBB_add_bytes(out, private_key_, sizeof(private_key_));
}
bool DeserializePrivateKey(CBS *in) override {
if (CBS_len(in) != sizeof(private_key_) ||
!CBS_copy_bytes(in, private_key_, sizeof(private_key_))) {
return false;
}
return true;
}
private:
uint8_t private_key_[32];
};
class CECPQ2KeyShare : public SSLKeyShare {
public:
CECPQ2KeyShare() {}
uint16_t GroupID() const override { return SSL_CURVE_CECPQ2; }
bool Offer(CBB *out) override {
uint8_t x25519_public_key[32];
X25519_keypair(x25519_public_key, x25519_private_key_);
uint8_t hrss_entropy[HRSS_GENERATE_KEY_BYTES];
HRSS_public_key hrss_public_key;
RAND_bytes(hrss_entropy, sizeof(hrss_entropy));
if (!HRSS_generate_key(&hrss_public_key, &hrss_private_key_,
hrss_entropy)) {
return false;
}
uint8_t hrss_public_key_bytes[HRSS_PUBLIC_KEY_BYTES];
HRSS_marshal_public_key(hrss_public_key_bytes, &hrss_public_key);
if (!CBB_add_bytes(out, x25519_public_key, sizeof(x25519_public_key)) ||
!CBB_add_bytes(out, hrss_public_key_bytes,
sizeof(hrss_public_key_bytes))) {
return false;
}
return true;
}
bool Accept(CBB *out_public_key, Array<uint8_t> *out_secret,
uint8_t *out_alert, Span<const uint8_t> peer_key) override {
Array<uint8_t> secret;
if (!secret.Init(32 + HRSS_KEY_BYTES)) {
OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
return false;
}
uint8_t x25519_public_key[32];
X25519_keypair(x25519_public_key, x25519_private_key_);
HRSS_public_key peer_public_key;
if (peer_key.size() != 32 + HRSS_PUBLIC_KEY_BYTES ||
!HRSS_parse_public_key(&peer_public_key, peer_key.data() + 32) ||
!X25519(secret.data(), x25519_private_key_, peer_key.data())) {
*out_alert = SSL_AD_DECODE_ERROR;
OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_ECPOINT);
return false;
}
uint8_t ciphertext[HRSS_CIPHERTEXT_BYTES];
uint8_t entropy[HRSS_ENCAP_BYTES];
RAND_bytes(entropy, sizeof(entropy));
if (!HRSS_encap(ciphertext, secret.data() + 32, &peer_public_key,
entropy) ||
!CBB_add_bytes(out_public_key, x25519_public_key,
sizeof(x25519_public_key)) ||
!CBB_add_bytes(out_public_key, ciphertext, sizeof(ciphertext))) {
return false;
}
*out_secret = std::move(secret);
return true;
}
bool Finish(Array<uint8_t> *out_secret, uint8_t *out_alert,
Span<const uint8_t> peer_key) override {
*out_alert = SSL_AD_INTERNAL_ERROR;
Array<uint8_t> secret;
if (!secret.Init(32 + HRSS_KEY_BYTES)) {
OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
return false;
}
if (peer_key.size() != 32 + HRSS_CIPHERTEXT_BYTES ||
!X25519(secret.data(), x25519_private_key_, peer_key.data())) {
*out_alert = SSL_AD_DECODE_ERROR;
OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_ECPOINT);
return false;
}
if (!HRSS_decap(secret.data() + 32, &hrss_private_key_,
peer_key.data() + 32, peer_key.size() - 32)) {
return false;
}
*out_secret = std::move(secret);
return true;
}
private:
uint8_t x25519_private_key_[32];
HRSS_private_key hrss_private_key_;
};
CONSTEXPR_ARRAY NamedGroup kNamedGroups[] = {
{NID_secp224r1, SSL_CURVE_SECP224R1, "P-224", "secp224r1"},
{NID_X9_62_prime256v1, SSL_CURVE_SECP256R1, "P-256", "prime256v1"},
{NID_secp384r1, SSL_CURVE_SECP384R1, "P-384", "secp384r1"},
{NID_secp521r1, SSL_CURVE_SECP521R1, "P-521", "secp521r1"},
{NID_X25519, SSL_CURVE_X25519, "X25519", "x25519"},
{NID_CECPQ2, SSL_CURVE_CECPQ2, "CECPQ2", "CECPQ2"},
};
} // namespace
Span<const NamedGroup> NamedGroups() {
return MakeConstSpan(kNamedGroups, OPENSSL_ARRAY_SIZE(kNamedGroups));
}
UniquePtr<SSLKeyShare> SSLKeyShare::Create(uint16_t group_id) {
switch (group_id) {
case SSL_CURVE_SECP224R1:
return UniquePtr<SSLKeyShare>(
New<ECKeyShare>(NID_secp224r1, SSL_CURVE_SECP224R1));
case SSL_CURVE_SECP256R1:
return UniquePtr<SSLKeyShare>(
New<ECKeyShare>(NID_X9_62_prime256v1, SSL_CURVE_SECP256R1));
case SSL_CURVE_SECP384R1:
return UniquePtr<SSLKeyShare>(
New<ECKeyShare>(NID_secp384r1, SSL_CURVE_SECP384R1));
case SSL_CURVE_SECP521R1:
return UniquePtr<SSLKeyShare>(
New<ECKeyShare>(NID_secp521r1, SSL_CURVE_SECP521R1));
case SSL_CURVE_X25519:
return UniquePtr<SSLKeyShare>(New<X25519KeyShare>());
case SSL_CURVE_CECPQ2:
return UniquePtr<SSLKeyShare>(New<CECPQ2KeyShare>());
default:
return nullptr;
}
}
UniquePtr<SSLKeyShare> SSLKeyShare::Create(CBS *in) {
uint64_t group;
CBS private_key;
if (!CBS_get_asn1_uint64(in, &group) || group > 0xffff ||
!CBS_get_asn1(in, &private_key, CBS_ASN1_OCTETSTRING)) {
return nullptr;
}
UniquePtr<SSLKeyShare> key_share = Create(static_cast<uint16_t>(group));
if (!key_share || !key_share->DeserializePrivateKey(&private_key)) {
return nullptr;
}
return key_share;
}
bool SSLKeyShare::Serialize(CBB *out) {
CBB private_key;
if (!CBB_add_asn1_uint64(out, GroupID()) ||
!CBB_add_asn1(out, &private_key, CBS_ASN1_OCTETSTRING) ||
!SerializePrivateKey(&private_key) || //
!CBB_flush(out)) {
return false;
}
return true;
}
bool SSLKeyShare::Accept(CBB *out_public_key, Array<uint8_t> *out_secret,
uint8_t *out_alert, Span<const uint8_t> peer_key) {
*out_alert = SSL_AD_INTERNAL_ERROR;
return Offer(out_public_key) &&
Finish(out_secret, out_alert, peer_key);
}
bool ssl_nid_to_group_id(uint16_t *out_group_id, int nid) {
for (const auto &group : kNamedGroups) {
if (group.nid == nid) {
*out_group_id = group.group_id;
return true;
}
}
return false;
}
bool ssl_name_to_group_id(uint16_t *out_group_id, const char *name, size_t len) {
for (const auto &group : kNamedGroups) {
if (len == strlen(group.name) &&
!strncmp(group.name, name, len)) {
*out_group_id = group.group_id;
return true;
}
if (len == strlen(group.alias) &&
!strncmp(group.alias, name, len)) {
*out_group_id = group.group_id;
return true;
}
}
return false;
}
BSSL_NAMESPACE_END
using namespace bssl;
const char* SSL_get_curve_name(uint16_t group_id) {
for (const auto &group : kNamedGroups) {
if (group.group_id == group_id) {
return group.name;
}
}
return nullptr;
}