torcontrol.cpp File Reference

#include <chainparams.h>
#include <torcontrol.h>
#include <util/strencodings.h>
#include <netbase.h>
#include <net.h>
#include <util/system.h>
#include <crypto/hmac_sha256.h>
#include <vector>
#include <deque>
#include <set>
#include <stdlib.h>
#include <boost/signals2/signal.hpp>
#include <boost/algorithm/string/split.hpp>
#include <boost/algorithm/string/classification.hpp>
#include <boost/algorithm/string/replace.hpp>
#include <event2/bufferevent.h>
#include <event2/buffer.h>
#include <event2/util.h>
#include <event2/event.h>
#include <event2/thread.h>

Classes
class	TorControlReply
class	TorControlConnection
class	TorController

Functions
std::pair< std::string, std::string >	SplitTorReplyLine (const std::string &s)
std::map< std::string, std::string >	ParseTorReplyMapping (const std::string &s)
static std::pair< bool, std::string >	ReadBinaryFile (const fs::path &filename, size_t maxsize=std::numeric_limits< size_t >::max())
static bool	WriteBinaryFile (const fs::path &filename, const std::string &data)
static std::vector< uint8_t >	ComputeResponse (const std::string &key, const std::vector< uint8_t > &cookie, const std::vector< uint8_t > &clientNonce, const std::vector< uint8_t > &serverNonce)
static void	TorControlThread ()
void	StartTorControl ()
void	InterruptTorControl ()
void	StopTorControl ()

Variables
const std::string	DEFAULT_TOR_CONTROL = "127.0.0.1:9051"
static const int	TOR_COOKIE_SIZE = 32
static const int	TOR_NONCE_SIZE = 32
static const std::string	TOR_SAFE_SERVERKEY = "Tor safe cookie authentication server-to-controller hash"
static const std::string	TOR_SAFE_CLIENTKEY = "Tor safe cookie authentication controller-to-server hash"
static const float	RECONNECT_TIMEOUT_START = 1.0
static const float	RECONNECT_TIMEOUT_EXP = 1.5
static const int	MAX_LINE_LENGTH = 100000
static struct event_base *	gBase
static std::thread	torControlThread

Function Documentation

ComputeResponse()

static std::vector<uint8_t> ComputeResponse ( const std::string &  key, const std::vector< uint8_t > &  cookie, const std::vector< uint8_t > &  clientNonce, const std::vector< uint8_t > &  serverNonce  )

static

Compute Tor SAFECOOKIE response.

ServerHash is computed as: HMAC-SHA256("Tor safe cookie authentication server-to-controller hash", CookieString | ClientNonce | ServerNonce) (with the HMAC key as its first argument)

After a controller sends a successful AUTHCHALLENGE command, the next command sent on the connection must be an AUTHENTICATE command, and the only authentication string which that AUTHENTICATE command will accept is:

HMAC-SHA256("Tor safe cookie authentication controller-to-server hash", CookieString | ClientNonce | ServerNonce)

InterruptTorControl()

void InterruptTorControl

(

)

ParseTorReplyMapping()

std::map<std::string,std::string> ParseTorReplyMapping

(

const std::string &

s

)

Parse reply arguments in the form 'METHODS=COOKIE,SAFECOOKIE COOKIEFILE=".../control_auth_cookie"'. Returns a map of keys to values, or an empty map if there was an error. Grammar is implicitly defined in https://spec.torproject.org/control-spec by the server reply formats for PROTOCOLINFO (S3.21), AUTHCHALLENGE (S3.24), and ADD_ONION (S3.27). See also sections 2.1 and 2.3.

Unescape value. Per https://spec.torproject.org/control-spec section 2.1.1:

For future-proofing, controller implementors MAY use the following rules to be compatible with buggy Tor implementations and with future ones that implement the spec as intended:

Read
\t \r and \0 ... \377 as C escapes. Treat a backslash followed by any other character as that character.

ReadBinaryFile()

static std::pair<bool,std::string> ReadBinaryFile ( const fs::path &  filename, size_t  maxsize = std::numeric_limits<size_t>::max()  )

static

Read full contents of a file and return them in a std::string. Returns a pair <status, string>. If an error occurred, status will be false, otherwise status will be true and the data will be returned in string.

Parameters

maxsize

Puts a maximum size limit on the file that is read. If the file is larger than this, truncated data (with len > maxsize) will be returned.

SplitTorReplyLine()

std::pair<std::string,std::string> SplitTorReplyLine

(

const std::string &

s

)

StartTorControl()

void StartTorControl

(

)

StopTorControl()

void StopTorControl

(

)

TorControlThread()

static void TorControlThread ( )

static

WriteBinaryFile()

static bool WriteBinaryFile ( const fs::path &  filename, const std::string &  data  )

static

Write contents of std::string to a file.

Returns

true on success.

Variable Documentation

DEFAULT_TOR_CONTROL

const std::string DEFAULT_TOR_CONTROL = "127.0.0.1:9051"

Default control port

gBase

struct event_base* gBase

static

MAX_LINE_LENGTH

const int MAX_LINE_LENGTH = 100000

static

Maximum length for lines received on TorControlConnection. tor-control-spec.txt mentions that there is explicitly no limit defined to line length, this is belt-and-suspenders sanity limit to prevent memory exhaustion.

RECONNECT_TIMEOUT_EXP

const float RECONNECT_TIMEOUT_EXP = 1.5

static

Exponential backoff configuration - growth factor

RECONNECT_TIMEOUT_START

const float RECONNECT_TIMEOUT_START = 1.0

static

Exponential backoff configuration - initial timeout in seconds

TOR_COOKIE_SIZE

const int TOR_COOKIE_SIZE = 32

static

Tor cookie size (from control-spec.txt)

TOR_NONCE_SIZE

const int TOR_NONCE_SIZE = 32

static

Size of client/server nonce for SAFECOOKIE

TOR_SAFE_CLIENTKEY

const std::string TOR_SAFE_CLIENTKEY = "Tor safe cookie authentication controller-to-server hash"

static

For computing clientHash in SAFECOOKIE

TOR_SAFE_SERVERKEY

const std::string TOR_SAFE_SERVERKEY = "Tor safe cookie authentication server-to-controller hash"

static

For computing serverHash in SAFECOOKIE

torControlThread

std::thread torControlThread

static