hs_circuit.c File Reference

#include "core/or/or.h"
#include "app/config/config.h"
#include "core/crypto/hs_ntor.h"
#include "core/or/circuitbuild.h"
#include "core/or/circuitlist.h"
#include "core/or/circuituse.h"
#include "core/or/policies.h"
#include "core/or/relay.h"
#include "core/or/crypt_path.h"
#include "core/or/extendinfo.h"
#include "feature/client/circpathbias.h"
#include "feature/hs/hs_cell.h"
#include "feature/hs/hs_circuit.h"
#include "feature/hs/hs_ob.h"
#include "feature/hs/hs_circuitmap.h"
#include "feature/hs/hs_client.h"
#include "feature/hs/hs_ident.h"
#include "feature/hs/hs_metrics.h"
#include "feature/hs/hs_service.h"
#include "feature/nodelist/describe.h"
#include "feature/nodelist/nodelist.h"
#include "feature/stats/rephist.h"
#include "lib/crypt_ops/crypto_dh.h"
#include "lib/crypt_ops/crypto_rand.h"
#include "lib/crypt_ops/crypto_util.h"
#include "trunnel/ed25519_cert.h"
#include "trunnel/hs/cell_common.h"
#include "trunnel/hs/cell_establish_intro.h"
#include "core/or/cpath_build_state_st.h"
#include "core/or/crypt_path_st.h"
#include "feature/nodelist/node_st.h"
#include "core/or/origin_circuit_st.h"

Go to the source code of this file.

Functions
static int	circuit_purpose_is_correct_for_rend (unsigned int circ_purpose, int is_service_side)
static crypt_path_t *	create_rend_cpath (const uint8_t *ntor_key_seed, size_t seed_len, int is_service_side)
static void	finalize_rend_circuit (origin_circuit_t *circ, crypt_path_t *hop, int is_service_side)
static void	register_intro_circ (const hs_service_intro_point_t *ip, origin_circuit_t *circ)
static unsigned int	count_opened_desc_intro_point_circuits (const hs_service_t *service, const hs_service_descriptor_t *desc)
STATIC hs_ident_circuit_t *	create_rp_circuit_identifier (const hs_service_t *service, const uint8_t *rendezvous_cookie, const curve25519_public_key_t *server_pk, const hs_ntor_rend_cell_keys_t *keys)
static hs_ident_circuit_t *	create_intro_circuit_identifier (const hs_service_t *service, const hs_service_intro_point_t *ip)
static void	send_establish_intro (const hs_service_t *service, hs_service_intro_point_t *ip, origin_circuit_t *circ)
static const char *	get_service_anonymity_string (const hs_service_t *service)
STATIC void	launch_rendezvous_point_circuit (const hs_service_t *service, const hs_service_intro_point_t *ip, const hs_cell_introduce2_data_t *data)
static int	can_relaunch_service_rendezvous_point (const origin_circuit_t *circ)
static void	retry_service_rendezvous_point (const origin_circuit_t *circ)
static int	setup_introduce1_data (const hs_desc_intro_point_t *ip, const node_t *rp_node, const hs_subcredential_t *subcredential, hs_cell_introduce1_data_t *intro1_data)
static void	cleanup_on_close_client_circ (circuit_t *circ)
static void	cleanup_on_free_client_circ (circuit_t *circ)
origin_circuit_t *	hs_circ_service_get_intro_circ (const hs_service_intro_point_t *ip)
origin_circuit_t *	hs_circ_service_get_established_intro_circ (const hs_service_intro_point_t *ip)
void	hs_circ_retry_service_rendezvous_point (origin_circuit_t *circ)
int	hs_circ_launch_intro_point (hs_service_t *service, const hs_service_intro_point_t *ip, extend_info_t *ei, bool direct_conn)
int	hs_circ_service_intro_has_opened (hs_service_t *service, hs_service_intro_point_t *ip, const hs_service_descriptor_t *desc, origin_circuit_t *circ)
void	hs_circ_service_rp_has_opened (const hs_service_t *service, origin_circuit_t *circ)
int	hs_circ_handle_intro_established (const hs_service_t *service, const hs_service_intro_point_t *ip, origin_circuit_t *circ, const uint8_t *payload, size_t payload_len)
static int	get_subcredential_for_handling_intro2_cell (const hs_service_t *service, hs_cell_introduce2_data_t *data, const hs_subcredential_t *desc_subcred)
int	hs_circ_handle_introduce2 (const hs_service_t *service, const origin_circuit_t *circ, hs_service_intro_point_t *ip, const hs_subcredential_t *subcredential, const uint8_t *payload, size_t payload_len)
int	hs_circuit_setup_e2e_rend_circ (origin_circuit_t *circ, const uint8_t *ntor_key_seed, size_t seed_len, int is_service_side)
int	hs_circ_send_introduce1 (origin_circuit_t *intro_circ, origin_circuit_t *rend_circ, const hs_desc_intro_point_t *ip, const hs_subcredential_t *subcredential)
int	hs_circ_send_establish_rendezvous (origin_circuit_t *circ)
void	hs_circ_cleanup_on_close (circuit_t *circ)
void	hs_circ_cleanup_on_free (circuit_t *circ)
void	hs_circ_cleanup_on_repurpose (circuit_t *circ)
bool	hs_circ_is_rend_sent_in_intro1 (const origin_circuit_t *circ)

Function Documentation

can_relaunch_service_rendezvous_point()

static int can_relaunch_service_rendezvous_point ( const origin_circuit_t *  circ )

static

Return true iff the given service rendezvous circuit circ is allowed for a relaunch to the rendezvous point.

Definition at line 418 of file hs_circuit.c.

Referenced by hs_circ_retry_service_rendezvous_point().

circuit_purpose_is_correct_for_rend()

static int circuit_purpose_is_correct_for_rend ( unsigned int  circ_purpose, int  is_service_side  )

static

A circuit is about to become an e2e rendezvous circuit. Check circ_purpose and ensure that it's properly set. Return true iff circuit purpose is properly set, otherwise return false.

Definition at line 50 of file hs_circuit.c.

cleanup_on_close_client_circ()

static void cleanup_on_close_client_circ ( circuit_t *  circ )

static

Helper: cleanup function for client circuit. This is for every HS version. It is called from hs_circ_cleanup_on_close() entry point.

Definition at line 563 of file hs_circuit.c.

Referenced by hs_circ_cleanup_on_close().

cleanup_on_free_client_circ()

static void cleanup_on_free_client_circ ( circuit_t *  circ )

static

Helper: cleanup function for client circuit. This is for every HS version. It is called from hs_circ_cleanup_on_free() entry point.

Definition at line 577 of file hs_circuit.c.

Referenced by hs_circ_cleanup_on_free().

count_opened_desc_intro_point_circuits()

static unsigned int count_opened_desc_intro_point_circuits ( const hs_service_t *  service, const hs_service_descriptor_t *  desc  )

static

Return the number of opened introduction circuit for the given circuit that is matching its identity key.

Definition at line 157 of file hs_circuit.c.

Referenced by hs_circ_service_intro_has_opened().

create_intro_circuit_identifier()

static hs_ident_circuit_t* create_intro_circuit_identifier ( const hs_service_t *  service, const hs_service_intro_point_t *  ip  )

static

From a given service and service intro point, create an introduction point circuit identifier. This can't fail.

Definition at line 228 of file hs_circuit.c.

create_rend_cpath()

static crypt_path_t* create_rend_cpath ( const uint8_t *  ntor_key_seed, size_t  seed_len, int  is_service_side  )

static

Create and return a crypt path for the final hop of a v3 prop224 rendezvous circuit. Initialize the crypt path crypto using the output material from the ntor key exchange at ntor_key_seed.

If is_service_side is set, we are the hidden service and the final hop of the rendezvous circuit is the client on the other side.

Definition at line 80 of file hs_circuit.c.

create_rp_circuit_identifier()

STATIC hs_ident_circuit_t* create_rp_circuit_identifier	(	const hs_service_t *	service,
		const uint8_t *	rendezvous_cookie,
		const curve25519_public_key_t *	server_pk,
		const hs_ntor_rend_cell_keys_t *	keys
	)

From a given service, rendezvous cookie and handshake info, create a rendezvous point circuit identifier. This can't fail.

Definition at line 189 of file hs_circuit.c.

finalize_rend_circuit()

static void finalize_rend_circuit ( origin_circuit_t *  circ, crypt_path_t *  hop, int  is_service_side  )

static

Append the final hop to the cpath of the rend circ, and mark circ ready for use to transfer HS relay cells.

Definition at line 110 of file hs_circuit.c.

get_service_anonymity_string()

static const char* get_service_anonymity_string ( const hs_service_t *  service )

static

Return a string constant describing the anonymity of service.

Definition at line 294 of file hs_circuit.c.

get_subcredential_for_handling_intro2_cell()

static int get_subcredential_for_handling_intro2_cell ( const hs_service_t *  service, hs_cell_introduce2_data_t *  data, const hs_subcredential_t *  desc_subcred  )

static

Go into data and add the right subcredential to be able to handle this incoming cell.

desc_subcred is the subcredential of the descriptor that corresponds to the intro point that received this intro request. This subcredential should be used if we are not an onionbalance instance.

Return 0 if everything went well, or -1 in case of internal error.

Definition at line 904 of file hs_circuit.c.

Referenced by hs_circ_handle_introduce2().

hs_circ_cleanup_on_close()

void hs_circ_cleanup_on_close

(

circuit_t *

circ

)

Circuit cleanup strategy:

What follows is a series of functions that notifies the HS subsystem of 3 different circuit cleanup phase: close, free and repurpose.

Tor can call any of those in any orders so they have to be safe between each other. In other words, the free should never depend on close to be called before.

The "on_close()" is called from circuit_mark_for_close() which is considered the tor fast path and thus as little work as possible should done in that function. Currently, we only remove the circuit from the HS circuit map and move on.

The "on_free()" is called from circuit circuit_free_() and it is very important that at the end of the function, no state or objects related to this circuit remains alive.

The "on_repurpose()" is called from circuit_change_purpose() for which we simply remove it from the HS circuit map. We do not have other cleanup requirements after that.

NOTE: The onion service code, specifically the service code, cleans up lingering objects or state if any of its circuit disappear which is why our cleanup strategy doesn't involve any service specific actions. As long as the circuit is removed from the HS circuit map, it won't be used. We are about to close this circ. Clean it up from any related HS data structures. This function can be called multiple times safely for the same circuit.

Definition at line 1198 of file hs_circuit.c.

hs_circ_cleanup_on_free()

void hs_circ_cleanup_on_free

(

circuit_t *

circ

)

We are about to free this circ. Clean it up from any related HS data structures. This function can be called multiple times safely for the same circuit.

Definition at line 1224 of file hs_circuit.c.

Referenced by circuit_free_().

hs_circ_cleanup_on_repurpose()

void hs_circ_cleanup_on_repurpose

(

circuit_t *

circ

)

We are about to repurpose this circ. Clean it up from any related HS data structures. This function can be called multiple times safely for the same circuit.

Definition at line 1245 of file hs_circuit.c.

hs_circ_handle_intro_established()

int hs_circ_handle_intro_established	(	const hs_service_t *	service,
		const hs_service_intro_point_t *	ip,
		origin_circuit_t *	circ,
		const uint8_t *	payload,
		size_t	payload_len
	)

Circ has been expecting an INTRO_ESTABLISHED cell that just arrived. Handle the INTRO_ESTABLISHED cell payload of length payload_len arriving on the given introduction circuit circ. The service is only used for logging purposes. Return 0 on success else a negative value.

Definition at line 855 of file hs_circuit.c.

hs_circ_handle_introduce2()

int hs_circ_handle_introduce2	(	const hs_service_t *	service,
		const origin_circuit_t *	circ,
		hs_service_intro_point_t *	ip,
		const hs_subcredential_t *	subcredential,
		const uint8_t *	payload,
		size_t	payload_len
	)

We just received an INTRODUCE2 cell on the established introduction circuit circ. Handle the INTRODUCE2 payload of size payload_len for the given circuit and service. This cell is associated with the intro point object ip and the subcredential. Return 0 on success else a negative value.

Definition at line 934 of file hs_circuit.c.

hs_circ_is_rend_sent_in_intro1()

bool hs_circ_is_rend_sent_in_intro1

(

const origin_circuit_t *

circ

)

Return true iff the given established client rendezvous circuit was sent into the INTRODUCE1 cell. This is called so we can take a decision on expiring or not the circuit.

The caller MUST make sure the circuit is an established client rendezvous circuit (purpose: CIRCUIT_PURPOSE_C_REND_READY).

This function supports all onion service versions.

Definition at line 1267 of file hs_circuit.c.

hs_circ_launch_intro_point()

int hs_circ_launch_intro_point	(	hs_service_t *	service,
		const hs_service_intro_point_t *	ip,
		extend_info_t *	ei,
		bool	direct_conn
	)

For a given service and a service intro point, launch a circuit to the extend info ei. If the service is a single onion, and direct_conn is true, a one-hop circuit will be requested.

Return 0 if the circuit was successfully launched and tagged with the correct identifier. On error, a negative value is returned.

Definition at line 663 of file hs_circuit.c.

hs_circ_retry_service_rendezvous_point()

void hs_circ_retry_service_rendezvous_point

(

origin_circuit_t *

circ

)

Called when we fail building a rendezvous circuit at some point other than the last hop: launches a new circuit to the same rendezvous point.

We currently relaunch connections to rendezvous points if:

• A rendezvous circuit timed out before connecting to RP.
• The rendezvous circuit failed to connect to the RP.

We avoid relaunching a connection to this rendezvous point if:

• We have already tried MAX_REND_FAILURES times to connect to this RP,
• We've been trying to connect to this RP for more than MAX_REND_TIMEOUT seconds, or
• We've already retried this specific rendezvous circuit.

Definition at line 633 of file hs_circuit.c.

hs_circ_send_establish_rendezvous()

int hs_circ_send_establish_rendezvous

(

origin_circuit_t *

circ

)

Send an ESTABLISH_RENDEZVOUS cell along the rendezvous circuit circ. On success, 0 is returned else -1 and the circuit is marked for close.

Definition at line 1118 of file hs_circuit.c.

hs_circ_send_introduce1()

int hs_circ_send_introduce1	(	origin_circuit_t *	intro_circ,
		origin_circuit_t *	rend_circ,
		const hs_desc_intro_point_t *	ip,
		const hs_subcredential_t *	subcredential
	)

Given the introduction circuit intro_circ, the rendezvous circuit rend_circ, a descriptor intro point object ip and the service's subcredential, send an INTRODUCE1 cell on intro_circ.

This will also setup the circuit identifier on rend_circ containing the key material for the handshake and e2e encryption. Return 0 on success else negative value. Because relay_send_command_from_edge() closes the circuit on error, it is possible that intro_circ is closed on error.

Definition at line 1039 of file hs_circuit.c.

hs_circ_service_get_established_intro_circ()

origin_circuit_t* hs_circ_service_get_established_intro_circ

(

const hs_service_intro_point_t *

ip

)

Return an introduction point established circuit matching the given intro point object. The circuit purpose has to be CIRCUIT_PURPOSE_S_INTRO. NULL is returned is no such circuit can be found.

Definition at line 606 of file hs_circuit.c.

hs_circ_service_get_intro_circ()

origin_circuit_t* hs_circ_service_get_intro_circ

(

const hs_service_intro_point_t *

ip

)

Return an introduction point circuit matching the given intro point object. NULL is returned is no such circuit can be found.

Definition at line 595 of file hs_circuit.c.

Referenced by should_remove_intro_point().

hs_circ_service_intro_has_opened()

int hs_circ_service_intro_has_opened	(	hs_service_t *	service,
		hs_service_intro_point_t *	ip,
		const hs_service_descriptor_t *	desc,
		origin_circuit_t *	circ
	)

Called when a service introduction point circuit is done building. Given the service and intro point object, this function will send the ESTABLISH_INTRO cell on the circuit. Return 0 on success. Return 1 if the circuit has been repurposed to General because we already have too many opened.

Definition at line 721 of file hs_circuit.c.

hs_circ_service_rp_has_opened()

void hs_circ_service_rp_has_opened	(	const hs_service_t *	service,
		origin_circuit_t *	circ
	)

Called when a service rendezvous point circuit is done building. Given the service and the circuit, this function will send a RENDEZVOUS1 cell on the circuit using the information in the circuit identifier. If the cell can't be sent, the circuit is closed.

Definition at line 789 of file hs_circuit.c.

hs_circuit_setup_e2e_rend_circ()

int hs_circuit_setup_e2e_rend_circ	(	origin_circuit_t *	circ,
		const uint8_t *	ntor_key_seed,
		size_t	seed_len,
		int	is_service_side
	)

Circuit circ just finished the rend ntor key exchange. Use the key exchange output material at ntor_key_seed and setup circ to serve as a rendezvous end-to-end circuit between the client and the service. If is_service_side is set, then we are the hidden service and the other side is the client.

Return 0 if the operation went well; in case of error return -1.

Definition at line 1008 of file hs_circuit.c.

launch_rendezvous_point_circuit()

STATIC void launch_rendezvous_point_circuit	(	const hs_service_t *	service,
		const hs_service_intro_point_t *	ip,
		const hs_cell_introduce2_data_t *	data
	)

For a given service, the ntor onion key and a rendezvous cookie, launch a circuit to the rendezvous point specified by the link specifiers. On success, a circuit identifier is attached to the circuit with the needed data. This function will try to open a circuit for a maximum value of MAX_REND_FAILURES then it will give up.

Definition at line 311 of file hs_circuit.c.

register_intro_circ()

static void register_intro_circ ( const hs_service_intro_point_t *  ip, origin_circuit_t *  circ  )

static

For a given circuit and a service introduction point object, register the intro circuit to the circuitmap.

Definition at line 144 of file hs_circuit.c.

retry_service_rendezvous_point()

static void retry_service_rendezvous_point ( const origin_circuit_t *  circ )

static

Retry the rendezvous point of circ by launching a new circuit to it.

Definition at line 464 of file hs_circuit.c.

Referenced by hs_circ_retry_service_rendezvous_point().

send_establish_intro()

static void send_establish_intro ( const hs_service_t *  service, hs_service_intro_point_t *  ip, origin_circuit_t *  circ  )

static

For a given introduction point and an introduction circuit, send the ESTABLISH_INTRO cell. The service object is used for logging. This can fail and if so, the circuit is closed and the intro point object is flagged that the circuit is not established anymore which is important for the retry mechanism.

Definition at line 248 of file hs_circuit.c.

setup_introduce1_data()

static int setup_introduce1_data ( const hs_desc_intro_point_t *  ip, const node_t *  rp_node, const hs_subcredential_t *  subcredential, hs_cell_introduce1_data_t *  intro1_data  )

static

Using the given descriptor intro point ip, the node of the rendezvous point rp_node and the service's subcredential, populate the already allocated intro1_data object with the needed key material and link specifiers.

Return 0 on success or a negative value if we couldn't properly filled the introduce1 data from the RP node. In other word, it means the RP node is unusable to use in the introduction.

Definition at line 520 of file hs_circuit.c.