1 /* Copyright (c) 2015, Google Inc.
3 * Permission to use, copy, modify, and/or distribute this software for any
4 * purpose with or without fee is hereby granted, provided that the above
5 * copyright notice and this permission notice appear in all copies.
7 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
8 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
9 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
10 * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
11 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
12 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
13 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
15 #include <openssl/ssl.h>
22 #include <openssl/bn.h>
23 #include <openssl/bytestring.h>
24 #include <openssl/curve25519.h>
25 #include <openssl/ec.h>
26 #include <openssl/err.h>
27 #include <openssl/mem.h>
28 #include <openssl/nid.h>
31 #include "../crypto/internal.h"
38 class ECKeyShare : public SSLKeyShare {
40 ECKeyShare(int nid, uint16_t group_id) : nid_(nid), group_id_(group_id) {}
41 ~ECKeyShare() override {}
43 uint16_t GroupID() const override { return group_id_; }
45 bool Offer(CBB *out) override {
46 assert(!private_key_);
47 // Set up a shared |BN_CTX| for all operations.
48 UniquePtr<BN_CTX> bn_ctx(BN_CTX_new());
52 BN_CTXScope scope(bn_ctx.get());
54 // Generate a private key.
55 UniquePtr<EC_GROUP> group(EC_GROUP_new_by_curve_name(nid_));
56 private_key_.reset(BN_new());
57 if (!group || !private_key_ ||
58 !BN_rand_range_ex(private_key_.get(), 1,
59 EC_GROUP_get0_order(group.get()))) {
63 // Compute the corresponding public key and serialize it.
64 UniquePtr<EC_POINT> public_key(EC_POINT_new(group.get()));
66 !EC_POINT_mul(group.get(), public_key.get(), private_key_.get(), NULL,
67 NULL, bn_ctx.get()) ||
68 !EC_POINT_point2cbb(out, group.get(), public_key.get(),
69 POINT_CONVERSION_UNCOMPRESSED, bn_ctx.get())) {
76 bool Finish(Array<uint8_t> *out_secret, uint8_t *out_alert,
77 Span<const uint8_t> peer_key) override {
79 *out_alert = SSL_AD_INTERNAL_ERROR;
81 // Set up a shared |BN_CTX| for all operations.
82 UniquePtr<BN_CTX> bn_ctx(BN_CTX_new());
86 BN_CTXScope scope(bn_ctx.get());
88 UniquePtr<EC_GROUP> group(EC_GROUP_new_by_curve_name(nid_));
93 UniquePtr<EC_POINT> peer_point(EC_POINT_new(group.get()));
94 UniquePtr<EC_POINT> result(EC_POINT_new(group.get()));
95 BIGNUM *x = BN_CTX_get(bn_ctx.get());
96 if (!peer_point || !result || !x) {
100 if (peer_key.empty() || peer_key[0] != POINT_CONVERSION_UNCOMPRESSED ||
101 !EC_POINT_oct2point(group.get(), peer_point.get(), peer_key.data(),
102 peer_key.size(), bn_ctx.get())) {
103 OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_ECPOINT);
104 *out_alert = SSL_AD_DECODE_ERROR;
108 // Compute the x-coordinate of |peer_key| * |private_key_|.
109 if (!EC_POINT_mul(group.get(), result.get(), NULL, peer_point.get(),
110 private_key_.get(), bn_ctx.get()) ||
111 !EC_POINT_get_affine_coordinates_GFp(group.get(), result.get(), x, NULL,
116 // Encode the x-coordinate left-padded with zeros.
117 Array<uint8_t> secret;
118 if (!secret.Init((EC_GROUP_get_degree(group.get()) + 7) / 8) ||
119 !BN_bn2bin_padded(secret.data(), secret.size(), x)) {
123 *out_secret = std::move(secret);
128 UniquePtr<BIGNUM> private_key_;
133 class X25519KeyShare : public SSLKeyShare {
136 ~X25519KeyShare() override {
137 OPENSSL_cleanse(private_key_, sizeof(private_key_));
140 uint16_t GroupID() const override { return SSL_CURVE_X25519; }
142 bool Offer(CBB *out) override {
143 uint8_t public_key[32];
144 X25519_keypair(public_key, private_key_);
145 return !!CBB_add_bytes(out, public_key, sizeof(public_key));
148 bool Finish(Array<uint8_t> *out_secret, uint8_t *out_alert,
149 Span<const uint8_t> peer_key) override {
150 *out_alert = SSL_AD_INTERNAL_ERROR;
152 Array<uint8_t> secret;
153 if (!secret.Init(32)) {
154 OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
158 if (peer_key.size() != 32 ||
159 !X25519(secret.data(), private_key_, peer_key.data())) {
160 *out_alert = SSL_AD_DECODE_ERROR;
161 OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_ECPOINT);
165 *out_secret = std::move(secret);
170 uint8_t private_key_[32];
173 CONSTEXPR_ARRAY struct {
176 const char name[8], alias[11];
178 {NID_secp224r1, SSL_CURVE_SECP224R1, "P-224", "secp224r1"},
179 {NID_X9_62_prime256v1, SSL_CURVE_SECP256R1, "P-256", "prime256v1"},
180 {NID_secp384r1, SSL_CURVE_SECP384R1, "P-384", "secp384r1"},
181 {NID_secp521r1, SSL_CURVE_SECP521R1, "P-521", "secp521r1"},
182 {NID_X25519, SSL_CURVE_X25519, "X25519", "x25519"},
187 UniquePtr<SSLKeyShare> SSLKeyShare::Create(uint16_t group_id) {
189 case SSL_CURVE_SECP224R1:
190 return UniquePtr<SSLKeyShare>(
191 New<ECKeyShare>(NID_secp224r1, SSL_CURVE_SECP224R1));
192 case SSL_CURVE_SECP256R1:
193 return UniquePtr<SSLKeyShare>(
194 New<ECKeyShare>(NID_X9_62_prime256v1, SSL_CURVE_SECP256R1));
195 case SSL_CURVE_SECP384R1:
196 return UniquePtr<SSLKeyShare>(
197 New<ECKeyShare>(NID_secp384r1, SSL_CURVE_SECP384R1));
198 case SSL_CURVE_SECP521R1:
199 return UniquePtr<SSLKeyShare>(
200 New<ECKeyShare>(NID_secp521r1, SSL_CURVE_SECP521R1));
201 case SSL_CURVE_X25519:
202 return UniquePtr<SSLKeyShare>(New<X25519KeyShare>());
208 bool SSLKeyShare::Accept(CBB *out_public_key, Array<uint8_t> *out_secret,
209 uint8_t *out_alert, Span<const uint8_t> peer_key) {
210 *out_alert = SSL_AD_INTERNAL_ERROR;
211 return Offer(out_public_key) &&
212 Finish(out_secret, out_alert, peer_key);
215 int ssl_nid_to_group_id(uint16_t *out_group_id, int nid) {
216 for (const auto &group : kNamedGroups) {
217 if (group.nid == nid) {
218 *out_group_id = group.group_id;
225 int ssl_name_to_group_id(uint16_t *out_group_id, const char *name, size_t len) {
226 for (const auto &group : kNamedGroups) {
227 if (len == strlen(group.name) &&
228 !strncmp(group.name, name, len)) {
229 *out_group_id = group.group_id;
232 if (len == strlen(group.alias) &&
233 !strncmp(group.alias, name, len)) {
234 *out_group_id = group.group_id;
243 using namespace bssl;
245 const char* SSL_get_curve_name(uint16_t group_id) {
246 for (const auto &group : kNamedGroups) {
247 if (group.group_id == group_id) {