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/* Copyright (c) 2017-2019, The Tor Project, Inc. */
/* See LICENSE for licensing information */
/**
* \file hs_ident.h
* \brief Header file containing circuit and connection identifier data for
* the whole HS subsytem.
*
* \details
* This interface is used to uniquely identify a hidden service on a circuit
* or connection using the service identity public key. Once the circuit or
* connection subsystem calls in the hidden service one, we use those
* identifiers to lookup the corresponding objects like service, intro point
* and descriptor.
*
* Furthermore, the circuit identifier holds cryptographic material needed for
* the e2e encryption on the rendezvous circuit which is set once the
* rendezvous circuit has opened and ready to be used.
**/
#ifndef TOR_HS_IDENT_H
#define TOR_HS_IDENT_H
#include "lib/crypt_ops/crypto_ed25519.h"
#include "feature/hs/hs_common.h"
/* Length of the rendezvous cookie that is used to connect circuits at the
* rendezvous point. */
#define HS_REND_COOKIE_LEN DIGEST_LEN
/* Type of circuit an hs_ident_t object is associated with. */
typedef enum {
HS_IDENT_CIRCUIT_INTRO = 1,
HS_IDENT_CIRCUIT_RENDEZVOUS = 2,
} hs_ident_circuit_type_t;
/* Client and service side circuit identifier that is used for hidden service
* circuit establishment. Not all fields contain data, it depends on the
* circuit purpose. This is attached to an origin_circuit_t. All fields are
* used by both client and service. */
typedef struct hs_ident_circuit_t {
/* (All circuit) The public key used to uniquely identify the service. It is
* the one found in the onion address. */
ed25519_public_key_t identity_pk;
/* (All circuit) The type of circuit this identifier is attached to.
* Accessors of the fields in this object assert non fatal on this circuit
* type. In other words, if a rendezvous field is being accessed, the
* circuit type MUST BE of type HS_IDENT_CIRCUIT_RENDEZVOUS. This value is
* set when an object is initialized in its constructor. */
hs_ident_circuit_type_t circuit_type;
/* (All circuit) Introduction point authentication key. It's also needed on
* the rendezvous circuit for the ntor handshake. It's used as the unique key
* of the introduction point so it should not be shared between multiple
* intro points. */
ed25519_public_key_t intro_auth_pk;
/* (Only client rendezvous circuit) Introduction point encryption public
* key. We keep it in the rendezvous identifier for the ntor handshake. */
curve25519_public_key_t intro_enc_pk;
/* (Only rendezvous circuit) Rendezvous cookie sent from the client to the
* service with an INTRODUCE1 cell and used by the service in an
* RENDEZVOUS1 cell. */
uint8_t rendezvous_cookie[HS_REND_COOKIE_LEN];
/* (Only service rendezvous circuit) The HANDSHAKE_INFO needed in the
* RENDEZVOUS1 cell of the service. The construction is as follows:
* SERVER_PK [32 bytes]
* AUTH_MAC [32 bytes]
*/
uint8_t rendezvous_handshake_info[CURVE25519_PUBKEY_LEN + DIGEST256_LEN];
/* (Only client rendezvous circuit) Client ephemeral keypair needed for the
* e2e encryption with the service. */
curve25519_keypair_t rendezvous_client_kp;
/* (Only rendezvous circuit) The NTOR_KEY_SEED needed for key derivation for
* the e2e encryption with the client on the circuit. */
uint8_t rendezvous_ntor_key_seed[DIGEST256_LEN];
/* (Only rendezvous circuit) Number of streams associated with this
* rendezvous circuit. We track this because there is a check on a maximum
* value. */
uint64_t num_rdv_streams;
} hs_ident_circuit_t;
/* Client and service side directory connection identifier used for a
* directory connection to identify which service is being queried. This is
* attached to a dir_connection_t. */
typedef struct hs_ident_dir_conn_t {
/* The public key used to uniquely identify the service. It is the one found
* in the onion address. */
ed25519_public_key_t identity_pk;
/* The blinded public key used to uniquely identify the descriptor that this
* directory connection identifier is for. Only used by the service-side code
* to fine control descriptor uploads. */
ed25519_public_key_t blinded_pk;
/* XXX: Client authorization. */
} hs_ident_dir_conn_t;
/* Client and service side edge connection identifier used for an edge
* connection to identify which service is being queried. This is attached to
* a edge_connection_t. */
typedef struct hs_ident_edge_conn_t {
/* The public key used to uniquely identify the service. It is the one found
* in the onion address. */
ed25519_public_key_t identity_pk;
/* The original virtual port that was used by the client to access the onion
* service, regardless of the internal port forwarding that might have
* happened on the service-side. */
uint16_t orig_virtual_port;
/* XXX: Client authorization. */
} hs_ident_edge_conn_t;
/* Circuit identifier API. */
hs_ident_circuit_t *hs_ident_circuit_new(
const ed25519_public_key_t *identity_pk,
hs_ident_circuit_type_t circuit_type);
void hs_ident_circuit_free_(hs_ident_circuit_t *ident);
#define hs_ident_circuit_free(id) \
FREE_AND_NULL(hs_ident_circuit_t, hs_ident_circuit_free_, (id))
hs_ident_circuit_t *hs_ident_circuit_dup(const hs_ident_circuit_t *src);
/* Directory connection identifier API. */
hs_ident_dir_conn_t *hs_ident_dir_conn_dup(const hs_ident_dir_conn_t *src);
void hs_ident_dir_conn_free_(hs_ident_dir_conn_t *ident);
#define hs_ident_dir_conn_free(id) \
FREE_AND_NULL(hs_ident_dir_conn_t, hs_ident_dir_conn_free_, (id))
void hs_ident_dir_conn_init(const ed25519_public_key_t *identity_pk,
const ed25519_public_key_t *blinded_pk,
hs_ident_dir_conn_t *ident);
/* Edge connection identifier API. */
hs_ident_edge_conn_t *hs_ident_edge_conn_new(
const ed25519_public_key_t *identity_pk);
void hs_ident_edge_conn_free_(hs_ident_edge_conn_t *ident);
#define hs_ident_edge_conn_free(id) \
FREE_AND_NULL(hs_ident_edge_conn_t, hs_ident_edge_conn_free_, (id))
/* Validators */
int hs_ident_intro_circ_is_valid(const hs_ident_circuit_t *ident);
#endif /* !defined(TOR_HS_IDENT_H) */
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