/* 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 #include #include #include #include #include #include #include #include #include #include "internal.h" #include "../crypto/internal.h" namespace bssl { namespace { class ECKeyShare : public SSLKeyShare { public: ECKeyShare(int nid, uint16_t group_id) : nid_(nid), group_id_(group_id) {} ~ECKeyShare() override {} 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_new()); if (!bn_ctx) { return false; } BN_CTXScope scope(bn_ctx.get()); // Generate a private key. UniquePtr 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 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(uint8_t **out_secret, size_t *out_secret_len, uint8_t *out_alert, const uint8_t *peer_key, size_t peer_key_len) override { assert(private_key_); *out_alert = SSL_AD_INTERNAL_ERROR; // Set up a shared |BN_CTX| for all operations. UniquePtr bn_ctx(BN_CTX_new()); if (!bn_ctx) { return false; } BN_CTXScope scope(bn_ctx.get()); UniquePtr group(EC_GROUP_new_by_curve_name(nid_)); if (!group) { return false; } UniquePtr peer_point(EC_POINT_new(group.get())); UniquePtr result(EC_POINT_new(group.get())); BIGNUM *x = BN_CTX_get(bn_ctx.get()); if (!peer_point || !result || !x) { return false; } if (!EC_POINT_oct2point(group.get(), peer_point.get(), peer_key, peer_key_len, bn_ctx.get())) { *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. size_t secret_len = (EC_GROUP_get_degree(group.get()) + 7) / 8; UniquePtr secret((uint8_t *)OPENSSL_malloc(secret_len)); if (!secret || !BN_bn2bin_padded(secret.get(), secret_len, x)) { return false; } *out_secret = secret.release(); *out_secret_len = secret_len; return true; } private: UniquePtr private_key_; int nid_; uint16_t group_id_; }; class X25519KeyShare : public SSLKeyShare { public: X25519KeyShare() {} ~X25519KeyShare() override { OPENSSL_cleanse(private_key_, sizeof(private_key_)); } 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(uint8_t **out_secret, size_t *out_secret_len, uint8_t *out_alert, const uint8_t *peer_key, size_t peer_key_len) override { *out_alert = SSL_AD_INTERNAL_ERROR; UniquePtr secret((uint8_t *)OPENSSL_malloc(32)); if (!secret) { OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE); return false; } if (peer_key_len != 32 || !X25519(secret.get(), private_key_, peer_key)) { *out_alert = SSL_AD_DECODE_ERROR; OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_ECPOINT); return false; } *out_secret = secret.release(); *out_secret_len = 32; return true; } private: uint8_t private_key_[32]; }; const struct { int nid; uint16_t group_id; const char name[8]; } kNamedGroups[] = { {NID_secp224r1, SSL_CURVE_SECP224R1, "P-224"}, {NID_X9_62_prime256v1, SSL_CURVE_SECP256R1, "P-256"}, {NID_secp384r1, SSL_CURVE_SECP384R1, "P-384"}, {NID_secp521r1, SSL_CURVE_SECP521R1, "P-521"}, {NID_X25519, SSL_CURVE_X25519, "X25519"}, }; } // namespace UniquePtr SSLKeyShare::Create(uint16_t group_id) { switch (group_id) { case SSL_CURVE_SECP224R1: return UniquePtr( New(NID_secp224r1, SSL_CURVE_SECP224R1)); case SSL_CURVE_SECP256R1: return UniquePtr( New(NID_X9_62_prime256v1, SSL_CURVE_SECP256R1)); case SSL_CURVE_SECP384R1: return UniquePtr( New(NID_secp384r1, SSL_CURVE_SECP384R1)); case SSL_CURVE_SECP521R1: return UniquePtr( New(NID_secp521r1, SSL_CURVE_SECP521R1)); case SSL_CURVE_X25519: return UniquePtr(New()); default: return nullptr; } } bool SSLKeyShare::Accept(CBB *out_public_key, uint8_t **out_secret, size_t *out_secret_len, uint8_t *out_alert, const uint8_t *peer_key, size_t peer_key_len) { *out_alert = SSL_AD_INTERNAL_ERROR; return Offer(out_public_key) && Finish(out_secret, out_secret_len, out_alert, peer_key, peer_key_len); } int 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 1; } } return 0; } int 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 1; } } return 0; } } // namespace bssl 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; }