/* Copyright (c) 2001 Matej Pfajfar.
* Copyright (c) 2001-2004, Roger Dingledine.
* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
* Copyright (c) 2007-2012, The Tor Project, Inc. */
/* See LICENSE for licensing information */
/**
* \file connection_or.c
* \brief Functions to handle OR connections, TLS handshaking, and
* cells on the network.
**/
#include "or.h"
#include "buffers.h"
#include "circuitbuild.h"
#include "circuitlist.h"
#include "command.h"
#include "config.h"
#include "connection.h"
#include "connection_or.h"
#include "control.h"
#include "dirserv.h"
#include "geoip.h"
#include "main.h"
#include "networkstatus.h"
#include "nodelist.h"
#include "reasons.h"
#include "relay.h"
#include "rephist.h"
#include "router.h"
#include "routerlist.h"
#ifdef USE_BUFFEREVENTS
#include <event2/bufferevent_ssl.h>
#endif
static int connection_tls_finish_handshake(or_connection_t *conn);
static int connection_or_launch_v3_or_handshake(or_connection_t *conn);
static int connection_or_process_cells_from_inbuf(or_connection_t *conn);
static int connection_or_check_valid_tls_handshake(or_connection_t *conn,
int started_here,
char *digest_rcvd_out);
static void connection_or_tls_renegotiated_cb(tor_tls_t *tls, void *_conn);
#ifdef USE_BUFFEREVENTS
static void connection_or_handle_event_cb(struct bufferevent *bufev,
short event, void *arg);
#include <event2/buffer.h>/*XXXX REMOVE */
#endif
/**************************************************************/
/** Map from identity digest of connected OR or desired OR to a connection_t
* with that identity digest. If there is more than one such connection_t,
* they form a linked list, with next_with_same_id as the next pointer. */
static digestmap_t *orconn_identity_map = NULL;
/** If conn is listed in orconn_identity_map, remove it, and clear
* conn->identity_digest. Otherwise do nothing. */
void
connection_or_remove_from_identity_map(or_connection_t *conn)
{
or_connection_t *tmp;
tor_assert(conn);
if (!orconn_identity_map)
return;
tmp = digestmap_get(orconn_identity_map, conn->identity_digest);
if (!tmp) {
if (!tor_digest_is_zero(conn->identity_digest)) {
log_warn(LD_BUG, "Didn't find connection '%s' on identity map when "
"trying to remove it.",
conn->nickname ? conn->nickname : "NULL");
}
return;
}
if (conn == tmp) {
if (conn->next_with_same_id)
digestmap_set(orconn_identity_map, conn->identity_digest,
conn->next_with_same_id);
else
digestmap_remove(orconn_identity_map, conn->identity_digest);
} else {
while (tmp->next_with_same_id) {
if (tmp->next_with_same_id == conn) {
tmp->next_with_same_id = conn->next_with_same_id;
break;
}
tmp = tmp->next_with_same_id;
}
}
memset(conn->identity_digest, 0, DIGEST_LEN);
conn->next_with_same_id = NULL;
}
/** Remove all entries from the identity-to-orconn map, and clear
* all identities in OR conns.*/
void
connection_or_clear_identity_map(void)
{
smartlist_t *conns = get_connection_array();
SMARTLIST_FOREACH(conns, connection_t *, conn,
{
if (conn->type == CONN_TYPE_OR) {
or_connection_t *or_conn = TO_OR_CONN(conn);
memset(or_conn->identity_digest, 0, DIGEST_LEN);
or_conn->next_with_same_id = NULL;
}
});
digestmap_free(orconn_identity_map, NULL);
orconn_identity_map = NULL;
}
/** Change conn->identity_digest to digest, and add conn into
* orconn_digest_map. */
static void
connection_or_set_identity_digest(or_connection_t *conn, const char *digest)
{
or_connection_t *tmp;
tor_assert(conn);
tor_assert(digest);
if (!orconn_identity_map)
orconn_identity_map = digestmap_new();
if (tor_memeq(conn->identity_digest, digest, DIGEST_LEN))
return;
/* If the identity was set previously, remove the old mapping. */
if (! tor_digest_is_zero(conn->identity_digest))
connection_or_remove_from_identity_map(conn);
memcpy(conn->identity_digest, digest, DIGEST_LEN);
/* If we're setting the ID to zero, don't add a mapping. */
if (tor_digest_is_zero(digest))
return;
tmp = digestmap_set(orconn_identity_map, digest, conn);
conn->next_with_same_id = tmp;
#if 1
/* Testing code to check for bugs in representation. */
for (; tmp; tmp = tmp->next_with_same_id) {
tor_assert(tor_memeq(tmp->identity_digest, digest, DIGEST_LEN));
tor_assert(tmp != conn);
}
#endif
}
/**************************************************************/
/** Map from a string describing what a non-open OR connection was doing when
* failed, to an intptr_t describing the count of connections that failed that
* way. Note that the count is stored _as_ the pointer.
*/
static strmap_t *broken_connection_counts;
/** If true, do not record information in <b>broken_connection_counts</b>. */
static int disable_broken_connection_counts = 0;
/** Record that an OR connection failed in <b>state</b>. */
static void
note_broken_connection(const char *state)
{
void *ptr;
intptr_t val;
if (disable_broken_connection_counts)
return;
if (!broken_connection_counts)
broken_connection_counts = strmap_new();
ptr = strmap_get(broken_connection_counts, state);
val = (intptr_t)ptr;
val++;
ptr = (void*)val;
strmap_set(broken_connection_counts, state, ptr);
}
/** Forget all recorded states for failed connections. If
* <b>stop_recording</b> is true, don't record any more. */
void
clear_broken_connection_map(int stop_recording)
{
if (broken_connection_counts)
strmap_free(broken_connection_counts, NULL);
broken_connection_counts = NULL;
if (stop_recording)
disable_broken_connection_counts = 1;
}
/** Write a detailed description the state of <b>orconn</b> into the
* <b>buflen</b>-byte buffer at <b>buf</b>. This description includes not
* only the OR-conn level state but also the TLS state. It's useful for
* diagnosing broken handshakes. */
static void
connection_or_get_state_description(or_connection_t *orconn,
char *buf, size_t buflen)
{
connection_t *conn = TO_CONN(orconn);
const char *conn_state;
char tls_state[256];
tor_assert(conn->type == CONN_TYPE_OR);
conn_state = conn_state_to_string(conn->type, conn->state);
tor_tls_get_state_description(orconn->tls, tls_state, sizeof(tls_state));
tor_snprintf(buf, buflen, "%s with SSL state %s", conn_state, tls_state);
}
/** Record the current state of <b>orconn</b> as the state of a broken
* connection. */
static void
connection_or_note_state_when_broken(or_connection_t *orconn)
{
char buf[256];
if (disable_broken_connection_counts)
return;
connection_or_get_state_description(orconn, buf, sizeof(buf));
log_info(LD_HANDSHAKE,"Connection died in state '%s'", buf);
note_broken_connection(buf);
}
/** Helper type used to sort connection states and find the most frequent. */
typedef struct broken_state_count_t {
intptr_t count;
const char *state;
} broken_state_count_t;
/** Helper function used to sort broken_state_count_t by frequency. */
static int
broken_state_count_compare(const void **a_ptr, const void **b_ptr)
{
const broken_state_count_t *a = *a_ptr, *b = *b_ptr;
if (b->count < a->count)
return -1;
else if (b->count == a->count)
return 0;
else
return 1;
}
/** Upper limit on the number of different states to report for connection
* failure. */
#define MAX_REASONS_TO_REPORT 10
/** Report a list of the top states for failed OR connections at log level
* <b>severity</b>, in log domain <b>domain</b>. */
void
connection_or_report_broken_states(int severity, int domain)
{
int total = 0;
smartlist_t *items;
if (!broken_connection_counts || disable_broken_connection_counts)
return;
items = smartlist_new();
STRMAP_FOREACH(broken_connection_counts, state, void *, countptr) {
broken_state_count_t *c = tor_malloc(sizeof(broken_state_count_t));
c->count = (intptr_t)countptr;
total += (int)c->count;
c->state = state;
smartlist_add(items, c);
} STRMAP_FOREACH_END;
smartlist_sort(items, broken_state_count_compare);
log(severity, domain, "%d connections have failed%s", total,
smartlist_len(items) > MAX_REASONS_TO_REPORT ? ". Top reasons:" : ":");
SMARTLIST_FOREACH_BEGIN(items, const broken_state_count_t *, c) {
if (c_sl_idx > MAX_REASONS_TO_REPORT)
break;
log(severity, domain,
" %d connections died in state %s", (int)c->count, c->state);
} SMARTLIST_FOREACH_END(c);
SMARTLIST_FOREACH(items, broken_state_count_t *, c, tor_free(c));
smartlist_free(items);
}
/**************************************************************/
/** Pack the cell_t host-order structure <b>src</b> into network-order
* in the buffer <b>dest</b>. See tor-spec.txt for details about the
* wire format.
*
* Note that this function doesn't touch <b>dst</b>-\>next: the caller
* should set it or clear it as appropriate.
*/
void
cell_pack(packed_cell_t *dst, const cell_t *src)
{
char *dest = dst->body;
set_uint16(dest, htons(src->circ_id));
*(uint8_t*)(dest+2) = src->command;
memcpy(dest+3, src->payload, CELL_PAYLOAD_SIZE);
}
/** Unpack the network-order buffer <b>src</b> into a host-order
* cell_t structure <b>dest</b>.
*/
static void
cell_unpack(cell_t *dest, const char *src)
{
dest->circ_id = ntohs(get_uint16(src));
dest->command = *(uint8_t*)(src+2);
memcpy(dest->payload, src+3, CELL_PAYLOAD_SIZE);
}
/** Write the header of <b>cell</b> into the first VAR_CELL_HEADER_SIZE
* bytes of <b>hdr_out</b>. */
void
var_cell_pack_header(const var_cell_t *cell, char *hdr_out)
{
set_uint16(hdr_out, htons(cell->circ_id));
set_uint8(hdr_out+2, cell->command);
set_uint16(hdr_out+3, htons(cell->payload_len));
}
/** Allocate and return a new var_cell_t with <b>payload_len</b> bytes of
* payload space. */
var_cell_t *
var_cell_new(uint16_t payload_len)
{
size_t size = STRUCT_OFFSET(var_cell_t, payload) + payload_len;
var_cell_t *cell = tor_malloc(size);
cell->payload_len = payload_len;
cell->command = 0;
cell->circ_id = 0;
return cell;
}
/** Release all space held by <b>cell</b>. */
void
var_cell_free(var_cell_t *cell)
{
tor_free(cell);
}
/** We've received an EOF from <b>conn</b>. Mark it for close and return. */
int
connection_or_reached_eof(or_connection_t *conn)
{
log_info(LD_OR,"OR connection reached EOF. Closing.");
connection_mark_for_close(TO_CONN(conn));
return 0;
}
/** Handle any new bytes that have come in on connection <b>conn</b>.
* If conn is in 'open' state, hand it to
* connection_or_process_cells_from_inbuf()
* (else do nothing).
*/
int
connection_or_process_inbuf(or_connection_t *conn)
{
/** Don't let the inbuf of a nonopen OR connection grow beyond this many
* bytes: it's either a broken client, a non-Tor client, or a DOS
* attempt. */
#define MAX_OR_INBUF_WHEN_NONOPEN 0
int ret = 0;
tor_assert(conn);
switch (conn->_base.state) {
case OR_CONN_STATE_PROXY_HANDSHAKING:
ret = connection_read_proxy_handshake(TO_CONN(conn));
/* start TLS after handshake completion, or deal with error */
if (ret == 1) {
tor_assert(TO_CONN(conn)->proxy_state == PROXY_CONNECTED);
if (connection_tls_start_handshake(conn, 0) < 0)
ret = -1;
}
if (ret < 0) {
connection_mark_for_close(TO_CONN(conn));
}
return ret;
case OR_CONN_STATE_TLS_SERVER_RENEGOTIATING:
#ifdef USE_BUFFEREVENTS
if (tor_tls_server_got_renegotiate(conn->tls))
connection_or_tls_renegotiated_cb(conn->tls, conn);
if (conn->_base.marked_for_close)
return 0;
/* fall through. */
#endif
case OR_CONN_STATE_OPEN:
case OR_CONN_STATE_OR_HANDSHAKING_V2:
case OR_CONN_STATE_OR_HANDSHAKING_V3:
return connection_or_process_cells_from_inbuf(conn);
default:
break; /* don't do anything */
}
/* This check was necessary with 0.2.2, when the TLS_SERVER_RENEGOTIATING
* check would otherwise just let data accumulate. It serves no purpose
* in 0.2.3.
*
* XXX024 Remove this check once we verify that the above paragraph is
* 100% true. */
if (buf_datalen(conn->_base.inbuf) > MAX_OR_INBUF_WHEN_NONOPEN) {
log_fn(LOG_PROTOCOL_WARN, LD_NET, "Accumulated too much data (%d bytes) "
"on nonopen OR connection %s %s:%u in state %s; closing.",
(int)buf_datalen(conn->_base.inbuf),
connection_or_nonopen_was_started_here(conn) ? "to" : "from",
conn->_base.address, conn->_base.port,
conn_state_to_string(conn->_base.type, conn->_base.state));
connection_mark_for_close(TO_CONN(conn));
ret = -1;
}
return ret;
}
/** When adding cells to an OR connection's outbuf, keep adding until the
* outbuf is at least this long, or we run out of cells. */
#define OR_CONN_HIGHWATER (32*1024)
/** Add cells to an OR connection's outbuf whenever the outbuf's data length
* drops below this size. */
#define OR_CONN_LOWWATER (16*1024)
/** Called whenever we have flushed some data on an or_conn: add more data
* from active circuits. */
int
connection_or_flushed_some(or_connection_t *conn)
{
size_t datalen = connection_get_outbuf_len(TO_CONN(conn));
/* If we're under the low water mark, add cells until we're just over the
* high water mark. */
if (datalen < OR_CONN_LOWWATER) {
ssize_t n = CEIL_DIV(OR_CONN_HIGHWATER - datalen, CELL_NETWORK_SIZE);
time_t now = approx_time();
while (conn->active_circuits && n > 0) {
int flushed;
flushed = connection_or_flush_from_first_active_circuit(conn, 1, now);
n -= flushed;
}
}
return 0;
}
/** Connection <b>conn</b> has finished writing and has no bytes left on
* its outbuf.
*
* Otherwise it's in state "open": stop writing and return.
*
* If <b>conn</b> is broken, mark it for close and return -1, else
* return 0.
*/
int
connection_or_finished_flushing(or_connection_t *conn)
{
tor_assert(conn);
assert_connection_ok(TO_CONN(conn),0);
switch (conn->_base.state) {
case OR_CONN_STATE_PROXY_HANDSHAKING:
case OR_CONN_STATE_OPEN:
case OR_CONN_STATE_OR_HANDSHAKING_V2:
case OR_CONN_STATE_OR_HANDSHAKING_V3:
break;
default:
log_err(LD_BUG,"Called in unexpected state %d.", conn->_base.state);
tor_fragile_assert();
return -1;
}
return 0;
}
/** Connected handler for OR connections: begin the TLS handshake.
*/
int
connection_or_finished_connecting(or_connection_t *or_conn)
{
const int proxy_type = or_conn->proxy_type;
connection_t *conn;
tor_assert(or_conn);
conn = TO_CONN(or_conn);
tor_assert(conn->state == OR_CONN_STATE_CONNECTING);
log_debug(LD_HANDSHAKE,"OR connect() to router at %s:%u finished.",
conn->address,conn->port);
control_event_bootstrap(BOOTSTRAP_STATUS_HANDSHAKE, 0);
if (proxy_type != PROXY_NONE) {
/* start proxy handshake */
if (connection_proxy_connect(conn, proxy_type) < 0) {
connection_mark_for_close(conn);
return -1;
}
connection_start_reading(conn);
conn->state = OR_CONN_STATE_PROXY_HANDSHAKING;
return 0;
}
if (connection_tls_start_handshake(or_conn, 0) < 0) {
/* TLS handshaking error of some kind. */
connection_mark_for_close(conn);
return -1;
}
return 0;
}
/** Called when we're about to finally unlink and free an OR connection:
* perform necessary accounting and cleanup */
void
connection_or_about_to_close(or_connection_t *or_conn)
{
time_t now = time(NULL);
connection_t *conn = TO_CONN(or_conn);
/* Remember why we're closing this connection. */
if (conn->state != OR_CONN_STATE_OPEN) {
/* Inform any pending (not attached) circs that they should
* give up. */
circuit_n_conn_done(TO_OR_CONN(conn), 0);
/* now mark things down as needed */
if (connection_or_nonopen_was_started_here(or_conn)) {
const or_options_t *options = get_options();
connection_or_note_state_when_broken(or_conn);
rep_hist_note_connect_failed(or_conn->identity_digest, now);
entry_guard_register_connect_status(or_conn->identity_digest,0,
!options->HTTPSProxy, now);
if (conn->state >= OR_CONN_STATE_TLS_HANDSHAKING) {
int reason = tls_error_to_orconn_end_reason(or_conn->tls_error);
control_event_or_conn_status(or_conn, OR_CONN_EVENT_FAILED,
reason);
if (!authdir_mode_tests_reachability(options))
control_event_bootstrap_problem(
orconn_end_reason_to_control_string(reason), reason);
}
}
} else if (conn->hold_open_until_flushed) {
/* We only set hold_open_until_flushed when we're intentionally
* closing a connection. */
rep_hist_note_disconnect(or_conn->identity_digest, now);
control_event_or_conn_status(or_conn, OR_CONN_EVENT_CLOSED,
tls_error_to_orconn_end_reason(or_conn->tls_error));
} else if (!tor_digest_is_zero(or_conn->identity_digest)) {
rep_hist_note_connection_died(or_conn->identity_digest, now);
control_event_or_conn_status(or_conn, OR_CONN_EVENT_CLOSED,
tls_error_to_orconn_end_reason(or_conn->tls_error));
}
/* Now close all the attached circuits on it. */
circuit_unlink_all_from_or_conn(TO_OR_CONN(conn),
END_CIRC_REASON_OR_CONN_CLOSED);
}
/** Return 1 if identity digest <b>id_digest</b> is known to be a
* currently or recently running relay. Otherwise return 0. */
int
connection_or_digest_is_known_relay(const char *id_digest)
{
if (router_get_consensus_status_by_id(id_digest))
return 1; /* It's in the consensus: "yes" */
if (router_get_by_id_digest(id_digest))
return 1; /* Not in the consensus, but we have a descriptor for
* it. Probably it was in a recent consensus. "Yes". */
return 0;
}
/** Set the per-conn read and write limits for <b>conn</b>. If it's a known
* relay, we will rely on the global read and write buckets, so give it
* per-conn limits that are big enough they'll never matter. But if it's
* not a known relay, first check if we set PerConnBwRate/Burst, then
* check if the consensus sets them, else default to 'big enough'.
*
* If <b>reset</b> is true, set the bucket to be full. Otherwise, just
* clip the bucket if it happens to be <em>too</em> full.
*/
static void
connection_or_update_token_buckets_helper(or_connection_t *conn, int reset,
const or_options_t *options)
{
int rate, burst; /* per-connection rate limiting params */
if (connection_or_digest_is_known_relay(conn->identity_digest)) {
/* It's in the consensus, or we have a descriptor for it meaning it
* was probably in a recent consensus. It's a recognized relay:
* give it full bandwidth. */
rate = (int)options->BandwidthRate;
burst = (int)options->BandwidthBurst;
} else {
/* Not a recognized relay. Squeeze it down based on the suggested
* bandwidth parameters in the consensus, but allow local config
* options to override. */
rate = options->PerConnBWRate ? (int)options->PerConnBWRate :
networkstatus_get_param(NULL, "perconnbwrate",
(int)options->BandwidthRate, 1, INT32_MAX);
burst = options->PerConnBWBurst ? (int)options->PerConnBWBurst :
networkstatus_get_param(NULL, "perconnbwburst",
(int)options->BandwidthBurst, 1, INT32_MAX);
}
conn->bandwidthrate = rate;
conn->bandwidthburst = burst;
#ifdef USE_BUFFEREVENTS
{
const struct timeval *tick = tor_libevent_get_one_tick_timeout();
struct ev_token_bucket_cfg *cfg, *old_cfg;
int64_t rate64 = (((int64_t)rate) * options->TokenBucketRefillInterval)
/ 1000;
/* This can't overflow, since TokenBucketRefillInterval <= 1000,
* and rate started out less than INT_MAX. */
int rate_per_tick = (int) rate64;
cfg = ev_token_bucket_cfg_new(rate_per_tick, burst, rate_per_tick,
burst, tick);
old_cfg = conn->bucket_cfg;
if (conn->_base.bufev)
tor_set_bufferevent_rate_limit(conn->_base.bufev, cfg);
if (old_cfg)
ev_token_bucket_cfg_free(old_cfg);
conn->bucket_cfg = cfg;
(void) reset; /* No way to do this with libevent yet. */
}
#else
if (reset) { /* set up the token buckets to be full */
conn->read_bucket = conn->write_bucket = burst;
return;
}
/* If the new token bucket is smaller, take out the extra tokens.
* (If it's larger, don't -- the buckets can grow to reach the cap.) */
if (conn->read_bucket > burst)
conn->read_bucket = burst;
if (conn->write_bucket > burst)
conn->write_bucket = burst;
#endif
}
/** Either our set of relays or our per-conn rate limits have changed.
* Go through all the OR connections and update their token buckets to make
* sure they don't exceed their maximum values. */
void
connection_or_update_token_buckets(smartlist_t *conns,
const or_options_t *options)
{
SMARTLIST_FOREACH(conns, connection_t *, conn,
{
if (connection_speaks_cells(conn))
connection_or_update_token_buckets_helper(TO_OR_CONN(conn), 0, options);
});
}
/** If we don't necessarily know the router we're connecting to, but we
* have an addr/port/id_digest, then fill in as much as we can. Start
* by checking to see if this describes a router we know.
* <b>started_here</b> is 1 if we are the initiator of <b>conn</b> and
* 0 if it's an incoming connection. */
void
connection_or_init_conn_from_address(or_connection_t *conn,
const tor_addr_t *addr, uint16_t port,
const char *id_digest,
int started_here)
{
const node_t *r = node_get_by_id(id_digest);
connection_or_set_identity_digest(conn, id_digest);
connection_or_update_token_buckets_helper(conn, 1, get_options());
conn->_base.port = port;
tor_addr_copy(&conn->_base.addr, addr);
tor_addr_copy(&conn->real_addr, addr);
if (r) {
tor_addr_port_t node_ap;
node_get_pref_orport(r, &node_ap);
/* XXXX proposal 186 is making this more complex. For now, a conn
is canonical when it uses the _preferred_ address. */
if (tor_addr_eq(&conn->_base.addr, &node_ap.addr))
conn->is_canonical = 1;
if (!started_here) {
/* Override the addr/port, so our log messages will make sense.
* This is dangerous, since if we ever try looking up a conn by
* its actual addr/port, we won't remember. Careful! */
/* XXXX arma: this is stupid, and it's the reason we need real_addr
* to track is_canonical properly. What requires it? */
/* XXXX <arma> i believe the reason we did this, originally, is because
* we wanted to log what OR a connection was to, and if we logged the
* right IP address and port 56244, that wouldn't be as helpful. now we
* log the "right" port too, so we know if it's moria1 or moria2.
*/
tor_addr_copy(&conn->_base.addr, &node_ap.addr);
conn->_base.port = node_ap.port;
}
conn->nickname = tor_strdup(node_get_nickname(r));
tor_free(conn->_base.address);
conn->_base.address = tor_dup_addr(&node_ap.addr);
} else {
const char *n;
/* If we're an authoritative directory server, we may know a
* nickname for this router. */
n = dirserv_get_nickname_by_digest(id_digest);
if (n) {
conn->nickname = tor_strdup(n);
} else {
conn->nickname = tor_malloc(HEX_DIGEST_LEN+2);
conn->nickname[0] = '$';
base16_encode(conn->nickname+1, HEX_DIGEST_LEN+1,
conn->identity_digest, DIGEST_LEN);
}
tor_free(conn->_base.address);
conn->_base.address = tor_dup_addr(addr);
}
}
/** Return true iff <b>a</b> is "better" than <b>b</b> for new circuits.
*
* A more canonical connection is always better than a less canonical
* connection. That aside, a connection is better if it has circuits and the
* other does not, or if it was created more recently.
*
* Requires that both input connections are open; not is_bad_for_new_circs,
* and not impossibly non-canonical.
*
* If <b>forgive_new_connections</b> is true, then we do not call
* <b>a</b>better than <b>b</b> simply because b has no circuits,
* unless b is also relatively old.
*/
static int
connection_or_is_better(time_t now,
const or_connection_t *a,
const or_connection_t *b,
int forgive_new_connections)
{
int newer;
/** Do not definitively deprecate a new connection with no circuits on it
* until this much time has passed. */
#define NEW_CONN_GRACE_PERIOD (15*60)
if (b->is_canonical && !a->is_canonical)
return 0; /* A canonical connection is better than a non-canonical
* one, no matter how new it is or which has circuits. */
newer = b->_base.timestamp_created < a->_base.timestamp_created;
if (
/* We prefer canonical connections regardless of newness. */
(!b->is_canonical && a->is_canonical) ||
/* If both have circuits we prefer the newer: */
(b->n_circuits && a->n_circuits && newer) ||
/* If neither has circuits we prefer the newer: */
(!b->n_circuits && !a->n_circuits && newer))
return 1;
/* If one has no circuits and the other does... */
if (!b->n_circuits && a->n_circuits) {
/* Then it's bad, unless it's in its grace period and we're forgiving. */
if (forgive_new_connections &&
now < b->_base.timestamp_created + NEW_CONN_GRACE_PERIOD)
return 0;
else
return 1;
}
return 0;
}
/** Return the OR connection we should use to extend a circuit to the router
* whose identity is <b>digest</b>, and whose address we believe (or have been
* told in an extend cell) is <b>target_addr</b>. If there is no good
* connection, set *<b>msg_out</b> to a message describing the connection's
* state and our next action, and set <b>launch_out</b> to a boolean for
* whether we should launch a new connection or not.
*/
or_connection_t *
connection_or_get_for_extend(const char *digest,
const tor_addr_t *target_addr,
const char **msg_out,
int *launch_out)
{
or_connection_t *conn, *best=NULL;
int n_inprogress_goodaddr = 0, n_old = 0, n_noncanonical = 0, n_possible = 0;
time_t now = approx_time();
tor_assert(msg_out);
tor_assert(launch_out);
if (!orconn_identity_map) {
*msg_out = "Router not connected (nothing is). Connecting.";
*launch_out = 1;
return NULL;
}
conn = digestmap_get(orconn_identity_map, digest);
for (; conn; conn = conn->next_with_same_id) {
tor_assert(conn->_base.magic == OR_CONNECTION_MAGIC);
tor_assert(conn->_base.type == CONN_TYPE_OR);
tor_assert(tor_memeq(conn->identity_digest, digest, DIGEST_LEN));
if (conn->_base.marked_for_close)
continue;
/* Never return a connection on which the other end appears to be
* a client. */
if (conn->is_connection_with_client) {
continue;
}
/* Never return a non-open connection. */
if (conn->_base.state != OR_CONN_STATE_OPEN) {
/* If the address matches, don't launch a new connection for this
* circuit. */
if (!tor_addr_compare(&conn->real_addr, target_addr, CMP_EXACT))
++n_inprogress_goodaddr;
continue;
}
/* Never return a connection that shouldn't be used for circs. */
if (conn->is_bad_for_new_circs) {
++n_old;
continue;
}
/* Never return a non-canonical connection using a recent link protocol
* if the address is not what we wanted.
*
* (For old link protocols, we can't rely on is_canonical getting
* set properly if we're talking to the right address, since we might
* have an out-of-date descriptor, and we will get no NETINFO cell to
* tell us about the right address.) */
if (!conn->is_canonical && conn->link_proto >= 2 &&
tor_addr_compare(&conn->real_addr, target_addr, CMP_EXACT)) {
++n_noncanonical;
continue;
}
++n_possible;
if (!best) {
best = conn; /* If we have no 'best' so far, this one is good enough. */
continue;
}
if (connection_or_is_better(now, conn, best, 0))
best = conn;
}
if (best) {
*msg_out = "Connection is fine; using it.";
*launch_out = 0;
return best;
} else if (n_inprogress_goodaddr) {
*msg_out = "Connection in progress; waiting.";
*launch_out = 0;
return NULL;
} else if (n_old || n_noncanonical) {
*msg_out = "Connections all too old, or too non-canonical. "
" Launching a new one.";
*launch_out = 1;
return NULL;
} else {
*msg_out = "Not connected. Connecting.";
*launch_out = 1;
return NULL;
}
}
/** How old do we let a connection to an OR get before deciding it's
* too old for new circuits? */
#define TIME_BEFORE_OR_CONN_IS_TOO_OLD (60*60*24*7)
/** Given the head of the linked list for all the or_connections with a given
* identity, set elements of that list as is_bad_for_new_circs as
* appropriate. Helper for connection_or_set_bad_connections().
*
* Specifically, we set the is_bad_for_new_circs flag on:
* - all connections if <b>force</b> is true.
* - all connections that are too old.
* - all open non-canonical connections for which a canonical connection
* exists to the same router.
* - all open canonical connections for which a 'better' canonical
* connection exists to the same router.
* - all open non-canonical connections for which a 'better' non-canonical
* connection exists to the same router at the same address.
*
* See connection_or_is_better() for our idea of what makes one OR connection
* better than another.
*/
static void
connection_or_group_set_badness(or_connection_t *head, int force)
{
or_connection_t *or_conn = NULL, *best = NULL;
int n_old = 0, n_inprogress = 0, n_canonical = 0, n_other = 0;
time_t now = time(NULL);
/* Pass 1: expire everything that's old, and see what the status of
* everything else is. */
for (or_conn = head; or_conn; or_conn = or_conn->next_with_same_id) {
if (or_conn->_base.marked_for_close ||
or_conn->is_bad_for_new_circs)
continue;
if (force ||
or_conn->_base.timestamp_created + TIME_BEFORE_OR_CONN_IS_TOO_OLD
< now) {
log_info(LD_OR,
"Marking OR conn to %s:%d as too old for new circuits "
"(fd %d, %d secs old).",
or_conn->_base.address, or_conn->_base.port, or_conn->_base.s,
(int)(now - or_conn->_base.timestamp_created));
or_conn->is_bad_for_new_circs = 1;
}
if (or_conn->is_bad_for_new_circs) {
++n_old;
} else if (or_conn->_base.state != OR_CONN_STATE_OPEN) {
++n_inprogress;
} else if (or_conn->is_canonical) {
++n_canonical;
} else {
++n_other;
}
}
/* Pass 2: We know how about how good the best connection is.
* expire everything that's worse, and find the very best if we can. */
for (or_conn = head; or_conn; or_conn = or_conn->next_with_same_id) {
if (or_conn->_base.marked_for_close ||
or_conn->is_bad_for_new_circs)
continue; /* This one doesn't need to be marked bad. */
if (or_conn->_base.state != OR_CONN_STATE_OPEN)
continue; /* Don't mark anything bad until we have seen what happens
* when the connection finishes. */
if (n_canonical && !or_conn->is_canonical) {
/* We have at least one open canonical connection to this router,
* and this one is open but not canonical. Mark it bad. */
log_info(LD_OR,
"Marking OR conn to %s:%d as unsuitable for new circuits: "
"(fd %d, %d secs old). It is not canonical, and we have "
"another connection to that OR that is.",
or_conn->_base.address, or_conn->_base.port, or_conn->_base.s,
(int)(now - or_conn->_base.timestamp_created));
or_conn->is_bad_for_new_circs = 1;
continue;
}
if (!best || connection_or_is_better(now, or_conn, best, 0))
best = or_conn;
}
if (!best)
return;
/* Pass 3: One connection to OR is best. If it's canonical, mark as bad
* every other open connection. If it's non-canonical, mark as bad
* every other open connection to the same address.
*
* XXXX This isn't optimal; if we have connections to an OR at multiple
* addresses, we'd like to pick the best _for each address_, and mark as
* bad every open connection that isn't best for its address. But this
* can only occur in cases where the other OR is old (so we have no
* canonical connection to it), or where all the connections to the OR are
* at noncanonical addresses and we have no good direct connection (which
* means we aren't at risk of attaching circuits to it anyway). As
* 0.1.2.x dies out, the first case will go away, and the second one is
* "mostly harmless", so a fix can wait until somebody is bored.
*/
for (or_conn = head; or_conn; or_conn = or_conn->next_with_same_id) {
if (or_conn->_base.marked_for_close ||
or_conn->is_bad_for_new_circs ||
or_conn->_base.state != OR_CONN_STATE_OPEN)
continue;
if (or_conn != best && connection_or_is_better(now, best, or_conn, 1)) {
/* This isn't the best conn, _and_ the best conn is better than it,
even when we're being forgiving. */
if (best->is_canonical) {
log_info(LD_OR,
"Marking OR conn to %s:%d as unsuitable for new circuits: "
"(fd %d, %d secs old). We have a better canonical one "
"(fd %d; %d secs old).",
or_conn->_base.address, or_conn->_base.port, or_conn->_base.s,
(int)(now - or_conn->_base.timestamp_created),
best->_base.s, (int)(now - best->_base.timestamp_created));
or_conn->is_bad_for_new_circs = 1;
} else if (!tor_addr_compare(&or_conn->real_addr,
&best->real_addr, CMP_EXACT)) {
log_info(LD_OR,
"Marking OR conn to %s:%d as unsuitable for new circuits: "
"(fd %d, %d secs old). We have a better one with the "
"same address (fd %d; %d secs old).",
or_conn->_base.address, or_conn->_base.port, or_conn->_base.s,
(int)(now - or_conn->_base.timestamp_created),
best->_base.s, (int)(now - best->_base.timestamp_created));
or_conn->is_bad_for_new_circs = 1;
}
}
}
}
/** Go through all the OR connections (or if <b>digest</b> is non-NULL, just
* the OR connections with that digest), and set the is_bad_for_new_circs
* flag based on the rules in connection_or_group_set_badness() (or just
* always set it if <b>force</b> is true).
*/
void
connection_or_set_bad_connections(const char *digest, int force)
{
if (!orconn_identity_map)
return;
DIGESTMAP_FOREACH(orconn_identity_map, identity, or_connection_t *, conn) {
if (!digest || tor_memeq(digest, conn->identity_digest, DIGEST_LEN))
connection_or_group_set_badness(conn, force);
} DIGESTMAP_FOREACH_END;
}
/** <b>conn</b> is in the 'connecting' state, and it failed to complete
* a TCP connection. Send notifications appropriately.
*
* <b>reason</b> specifies the or_conn_end_reason for the failure;
* <b>msg</b> specifies the strerror-style error message.
*/
void
connection_or_connect_failed(or_connection_t *conn,
int reason, const char *msg)
{
control_event_or_conn_status(conn, OR_CONN_EVENT_FAILED, reason);
if (!authdir_mode_tests_reachability(get_options()))
control_event_bootstrap_problem(msg, reason);
}
/** Launch a new OR connection to <b>addr</b>:<b>port</b> and expect to
* handshake with an OR with identity digest <b>id_digest</b>.
*
* If <b>id_digest</b> is me, do nothing. If we're already connected to it,
* return that connection. If the connect() is in progress, set the
* new conn's state to 'connecting' and return it. If connect() succeeds,
* call connection_tls_start_handshake() on it.
*
* This function is called from router_retry_connections(), for
* ORs connecting to ORs, and circuit_establish_circuit(), for
* OPs connecting to ORs.
*
* Return the launched conn, or NULL if it failed.
*/
or_connection_t *
connection_or_connect(const tor_addr_t *_addr, uint16_t port,
const char *id_digest)
{
or_connection_t *conn;
const or_options_t *options = get_options();
int socket_error = 0;
tor_addr_t addr;
int r;
tor_addr_t proxy_addr;
uint16_t proxy_port;
int proxy_type;
tor_assert(_addr);
tor_assert(id_digest);
tor_addr_copy(&addr, _addr);
if (server_mode(options) && router_digest_is_me(id_digest)) {
log_info(LD_PROTOCOL,"Client asked me to connect to myself. Refusing.");
return NULL;
}
conn = or_connection_new(tor_addr_family(&addr));
/* set up conn so it's got all the data we need to remember */
connection_or_init_conn_from_address(conn, &addr, port, id_digest, 1);
conn->_base.state = OR_CONN_STATE_CONNECTING;
control_event_or_conn_status(conn, OR_CONN_EVENT_LAUNCHED, 0);
conn->is_outgoing = 1;
/* If we are using a proxy server, find it and use it. */
r = get_proxy_addrport(&proxy_addr, &proxy_port, &proxy_type, TO_CONN(conn));
if (r == 0) {
conn->proxy_type = proxy_type;
if (proxy_type != PROXY_NONE) {
tor_addr_copy(&addr, &proxy_addr);
port = proxy_port;
conn->_base.proxy_state = PROXY_INFANT;
}
} else {
/* get_proxy_addrport() might fail if we have a Bridge line that
references a transport, but no ClientTransportPlugin lines
defining its transport proxy. If this is the case, let's try to
output a useful log message to the user. */
const char *transport_name =
find_transport_name_by_bridge_addrport(&TO_CONN(conn)->addr,
TO_CONN(conn)->port);
if (transport_name) {
log_warn(LD_GENERAL, "We were supposed to connect to bridge '%s:%u' "
"using pluggable transport '%s', but we can't find a pluggable "
"transport proxy supporting '%s'. This can happen if you "
"haven't provided a ClientTransportPlugin line, or if "
"your pluggable transport proxy stopped running.",
fmt_addr(&TO_CONN(conn)->addr), TO_CONN(conn)->port,
transport_name, transport_name);
} else {
log_warn(LD_GENERAL, "Tried to connect to '%s:%u' through a proxy, but "
"the proxy address could not be found.",
fmt_addr(&TO_CONN(conn)->addr), TO_CONN(conn)->port);
}
connection_free(TO_CONN(conn));
return NULL;
}
switch (connection_connect(TO_CONN(conn), conn->_base.address,
&addr, port, &socket_error)) {
case -1:
/* If the connection failed immediately, and we're using
* a proxy, our proxy is down. Don't blame the Tor server. */
if (conn->_base.proxy_state == PROXY_INFANT)
entry_guard_register_connect_status(conn->identity_digest,
0, 1, time(NULL));
connection_or_connect_failed(conn,
errno_to_orconn_end_reason(socket_error),
tor_socket_strerror(socket_error));
connection_free(TO_CONN(conn));
return NULL;
case 0:
connection_watch_events(TO_CONN(conn), READ_EVENT | WRITE_EVENT);
/* writable indicates finish, readable indicates broken link,
error indicates broken link on windows */
return conn;
/* case 1: fall through */
}
if (connection_or_finished_connecting(conn) < 0) {
/* already marked for close */
return NULL;
}
return conn;
}
/** Begin the tls handshake with <b>conn</b>. <b>receiving</b> is 0 if
* we initiated the connection, else it's 1.
*
* Assign a new tls object to conn->tls, begin reading on <b>conn</b>, and
* pass <b>conn</b> to connection_tls_continue_handshake().
*
* Return -1 if <b>conn</b> is broken, else return 0.
*/
int
connection_tls_start_handshake(or_connection_t *conn, int receiving)
{
conn->_base.state = OR_CONN_STATE_TLS_HANDSHAKING;
tor_assert(!conn->tls);
conn->tls = tor_tls_new(conn->_base.s, receiving);
if (!conn->tls) {
log_warn(LD_BUG,"tor_tls_new failed. Closing.");
return -1;
}
tor_tls_set_logged_address(conn->tls, // XXX client and relay?
escaped_safe_str(conn->_base.address));
#ifdef USE_BUFFEREVENTS
if (connection_type_uses_bufferevent(TO_CONN(conn))) {
const int filtering = get_options()->_UseFilteringSSLBufferevents;
struct bufferevent *b =
tor_tls_init_bufferevent(conn->tls, conn->_base.bufev, conn->_base.s,
receiving, filtering);
if (!b) {
log_warn(LD_BUG,"tor_tls_init_bufferevent failed. Closing.");
return -1;
}
conn->_base.bufev = b;
if (conn->bucket_cfg)
tor_set_bufferevent_rate_limit(conn->_base.bufev, conn->bucket_cfg);
connection_enable_rate_limiting(TO_CONN(conn));
connection_configure_bufferevent_callbacks(TO_CONN(conn));
bufferevent_setcb(b,
connection_handle_read_cb,
connection_handle_write_cb,
connection_or_handle_event_cb,/* overriding this one*/
TO_CONN(conn));
}
#endif
connection_start_reading(TO_CONN(conn));
log_debug(LD_HANDSHAKE,"starting TLS handshake on fd %d", conn->_base.s);
note_crypto_pk_op(receiving ? TLS_HANDSHAKE_S : TLS_HANDSHAKE_C);
IF_HAS_BUFFEREVENT(TO_CONN(conn), {
/* ???? */;
}) ELSE_IF_NO_BUFFEREVENT {
if (connection_tls_continue_handshake(conn) < 0)
return -1;
}
return 0;
}
/** Block all future attempts to renegotiate on 'conn' */
void
connection_or_block_renegotiation(or_connection_t *conn)
{
tor_tls_t *tls = conn->tls;
if (!tls)
return;
tor_tls_set_renegotiate_callback(tls, NULL, NULL);
tor_tls_block_renegotiation(tls);
}
/** Invoked on the server side from inside tor_tls_read() when the server
* gets a successful TLS renegotiation from the client. */
static void
connection_or_tls_renegotiated_cb(tor_tls_t *tls, void *_conn)
{
or_connection_t *conn = _conn;
(void)tls;
/* Don't invoke this again. */
connection_or_block_renegotiation(conn);
if (connection_tls_finish_handshake(conn) < 0) {
/* XXXX_TLS double-check that it's ok to do this from inside read. */
/* XXXX_TLS double-check that this verifies certificates. */
connection_mark_for_close(TO_CONN(conn));
}
}
/** Move forward with the tls handshake. If it finishes, hand
* <b>conn</b> to connection_tls_finish_handshake().
*
* Return -1 if <b>conn</b> is broken, else return 0.
*/
int
connection_tls_continue_handshake(or_connection_t *conn)
{
int result;
check_no_tls_errors();
again:
if (conn->_base.state == OR_CONN_STATE_TLS_CLIENT_RENEGOTIATING) {
// log_notice(LD_OR, "Renegotiate with %p", conn->tls);
result = tor_tls_renegotiate(conn->tls);
// log_notice(LD_OR, "Result: %d", result);
} else {
tor_assert(conn->_base.state == OR_CONN_STATE_TLS_HANDSHAKING);
// log_notice(LD_OR, "Continue handshake with %p", conn->tls);
result = tor_tls_handshake(conn->tls);
// log_notice(LD_OR, "Result: %d", result);
}
switch (result) {
CASE_TOR_TLS_ERROR_ANY:
log_info(LD_OR,"tls error [%s]. breaking connection.",
tor_tls_err_to_string(result));
return -1;
case TOR_TLS_DONE:
if (! tor_tls_used_v1_handshake(conn->tls)) {
if (!tor_tls_is_server(conn->tls)) {
if (conn->_base.state == OR_CONN_STATE_TLS_HANDSHAKING) {
if (tor_tls_received_v3_certificate(conn->tls)) {
log_info(LD_OR, "Client got a v3 cert! Moving on to v3 "
"handshake.");
return connection_or_launch_v3_or_handshake(conn);
} else {
log_debug(LD_OR, "Done with initial SSL handshake (client-side)."
" Requesting renegotiation.");
conn->_base.state = OR_CONN_STATE_TLS_CLIENT_RENEGOTIATING;
goto again;
}
}
// log_notice(LD_OR,"Done. state was %d.", conn->_base.state);
} else {
/* v2/v3 handshake, but not a client. */
log_debug(LD_OR, "Done with initial SSL handshake (server-side). "
"Expecting renegotiation or VERSIONS cell");
tor_tls_set_renegotiate_callback(conn->tls,
connection_or_tls_renegotiated_cb,
conn);
conn->_base.state = OR_CONN_STATE_TLS_SERVER_RENEGOTIATING;
connection_stop_writing(TO_CONN(conn));
connection_start_reading(TO_CONN(conn));
return 0;
}
}
return connection_tls_finish_handshake(conn);
case TOR_TLS_WANTWRITE:
connection_start_writing(TO_CONN(conn));
log_debug(LD_OR,"wanted write");
return 0;
case TOR_TLS_WANTREAD: /* handshaking conns are *always* reading */
log_debug(LD_OR,"wanted read");
return 0;
case TOR_TLS_CLOSE:
log_info(LD_OR,"tls closed. breaking connection.");
return -1;
}
return 0;
}
#ifdef USE_BUFFEREVENTS
static void
connection_or_handle_event_cb(struct bufferevent *bufev, short event,
void *arg)
{
struct or_connection_t *conn = TO_OR_CONN(arg);
/* XXXX cut-and-paste code; should become a function. */
if (event & BEV_EVENT_CONNECTED) {
if (conn->_base.state == OR_CONN_STATE_TLS_HANDSHAKING) {
if (tor_tls_finish_handshake(conn->tls) < 0) {
log_warn(LD_OR, "Problem finishing handshake");
connection_mark_for_close(TO_CONN(conn));
return;
}
}
if (! tor_tls_used_v1_handshake(conn->tls)) {
if (!tor_tls_is_server(conn->tls)) {
if (conn->_base.state == OR_CONN_STATE_TLS_HANDSHAKING) {
if (tor_tls_received_v3_certificate(conn->tls)) {
log_info(LD_OR, "Client got a v3 cert!");
if (connection_or_launch_v3_or_handshake(conn) < 0)
connection_mark_for_close(TO_CONN(conn));
return;
} else {
conn->_base.state = OR_CONN_STATE_TLS_CLIENT_RENEGOTIATING;
tor_tls_unblock_renegotiation(conn->tls);
if (bufferevent_ssl_renegotiate(conn->_base.bufev)<0) {
log_warn(LD_OR, "Start_renegotiating went badly.");
connection_mark_for_close(TO_CONN(conn));
}
tor_tls_unblock_renegotiation(conn->tls);
return; /* ???? */
}
}
} else {
const int handshakes = tor_tls_get_num_server_handshakes(conn->tls);
if (handshakes == 1) {
/* v2 or v3 handshake, as a server. Only got one handshake, so
* wait for the next one. */
tor_tls_set_renegotiate_callback(conn->tls,
connection_or_tls_renegotiated_cb,
conn);
conn->_base.state = OR_CONN_STATE_TLS_SERVER_RENEGOTIATING;
} else if (handshakes == 2) {
/* v2 handshake, as a server. Two handshakes happened already,
* so we treat renegotiation as done.
*/
connection_or_tls_renegotiated_cb(conn->tls, conn);
} else if (handshakes > 2) {
log_warn(LD_OR, "More than two handshakes done on connection. "
"Closing.");
connection_mark_for_close(TO_CONN(conn));
} else {
log_warn(LD_BUG, "We were unexpectedly told that a connection "
"got %d handshakes. Closing.", handshakes);
connection_mark_for_close(TO_CONN(conn));
}
return;
}
}
connection_watch_events(TO_CONN(conn), READ_EVENT|WRITE_EVENT);
if (connection_tls_finish_handshake(conn) < 0)
connection_mark_for_close(TO_CONN(conn)); /* ???? */
return;
}
if (event & BEV_EVENT_ERROR) {
unsigned long err;
while ((err = bufferevent_get_openssl_error(bufev))) {
tor_tls_log_one_error(conn->tls, err, LOG_WARN, LD_OR,
"handshaking (with bufferevent)");
}
}
connection_handle_event_cb(bufev, event, arg);
}
#endif
/** Return 1 if we initiated this connection, or 0 if it started
* out as an incoming connection.
*/
int
connection_or_nonopen_was_started_here(or_connection_t *conn)
{
tor_assert(conn->_base.type == CONN_TYPE_OR);
if (!conn->tls)
return 1; /* it's still in proxy states or something */
if (conn->handshake_state)
return conn->handshake_state->started_here;
return !tor_tls_is_server(conn->tls);
}
/** Set the circid_type field of <b>conn</b> (which determines which part of
* the circuit ID space we're willing to use) based on comparing our ID to
* <b>identity_rcvd</b> */
void
connection_or_set_circid_type(or_connection_t *conn,
crypto_pk_t *identity_rcvd)
{
const int started_here = connection_or_nonopen_was_started_here(conn);
crypto_pk_t *our_identity =
started_here ? get_tlsclient_identity_key() :
get_server_identity_key();
if (identity_rcvd) {
if (crypto_pk_cmp_keys(our_identity, identity_rcvd)<0) {
conn->circ_id_type = CIRC_ID_TYPE_LOWER;
} else {
conn->circ_id_type = CIRC_ID_TYPE_HIGHER;
}
} else {
conn->circ_id_type = CIRC_ID_TYPE_NEITHER;
}
}
/** <b>Conn</b> just completed its handshake. Return 0 if all is well, and
* return -1 if he is lying, broken, or otherwise something is wrong.
*
* If we initiated this connection (<b>started_here</b> is true), make sure
* the other side sent a correctly formed certificate. If I initiated the
* connection, make sure it's the right guy.
*
* Otherwise (if we _didn't_ initiate this connection), it's okay for
* the certificate to be weird or absent.
*
* If we return 0, and the certificate is as expected, write a hash of the
* identity key into <b>digest_rcvd_out</b>, which must have DIGEST_LEN
* space in it.
* If the certificate is invalid or missing on an incoming connection,
* we return 0 and set <b>digest_rcvd_out</b> to DIGEST_LEN NUL bytes.
* (If we return -1, the contents of this buffer are undefined.)
*
* As side effects,
* 1) Set conn->circ_id_type according to tor-spec.txt.
* 2) If we're an authdirserver and we initiated the connection: drop all
* descriptors that claim to be on that IP/port but that aren't
* this guy; and note that this guy is reachable.
* 3) If this is a bridge and we didn't configure its identity
* fingerprint, remember the keyid we just learned.
*/
static int
connection_or_check_valid_tls_handshake(or_connection_t *conn,
int started_here,
char *digest_rcvd_out)
{
crypto_pk_t *identity_rcvd=NULL;
const or_options_t *options = get_options();
int severity = server_mode(options) ? LOG_PROTOCOL_WARN : LOG_WARN;
const char *safe_address =
started_here ? conn->_base.address :
safe_str_client(conn->_base.address);
const char *conn_type = started_here ? "outgoing" : "incoming";
int has_cert = 0;
check_no_tls_errors();
has_cert = tor_tls_peer_has_cert(conn->tls);
if (started_here && !has_cert) {
log_info(LD_HANDSHAKE,"Tried connecting to router at %s:%d, but it didn't "
"send a cert! Closing.",
safe_address, conn->_base.port);
return -1;
} else if (!has_cert) {
log_debug(LD_HANDSHAKE,"Got incoming connection with no certificate. "
"That's ok.");
}
check_no_tls_errors();
if (has_cert) {
int v = tor_tls_verify(started_here?severity:LOG_INFO,
conn->tls, &identity_rcvd);
if (started_here && v<0) {
log_fn(severity,LD_HANDSHAKE,"Tried connecting to router at %s:%d: It"
" has a cert but it's invalid. Closing.",
safe_address, conn->_base.port);
return -1;
} else if (v<0) {
log_info(LD_HANDSHAKE,"Incoming connection gave us an invalid cert "
"chain; ignoring.");
} else {
log_debug(LD_HANDSHAKE,
"The certificate seems to be valid on %s connection "
"with %s:%d", conn_type, safe_address, conn->_base.port);
}
check_no_tls_errors();
}
if (identity_rcvd) {
crypto_pk_get_digest(identity_rcvd, digest_rcvd_out);
} else {
memset(digest_rcvd_out, 0, DIGEST_LEN);
}
connection_or_set_circid_type(conn, identity_rcvd);
crypto_pk_free(identity_rcvd);
if (started_here)
return connection_or_client_learned_peer_id(conn,
(const uint8_t*)digest_rcvd_out);
return 0;
}
/** Called when we (as a connection initiator) have definitively,
* authenticatedly, learned that ID of the Tor instance on the other
* side of <b>conn</b> is <b>peer_id</b>. For v1 and v2 handshakes,
* this is right after we get a certificate chain in a TLS handshake
* or renegotiation. For v3 handshakes, this is right after we get a
* certificate chain in a CERTS cell.
*
* If we want any particular ID before, record the one we got.
*
* If we wanted an ID, but we didn't get it, log a warning and return -1.
*
* If we're testing reachability, remember what we learned.
*
* Return 0 on success, -1 on failure.
*/
int
connection_or_client_learned_peer_id(or_connection_t *conn,
const uint8_t *peer_id)
{
const or_options_t *options = get_options();
int severity = server_mode(options) ? LOG_PROTOCOL_WARN : LOG_WARN;
if (tor_digest_is_zero(conn->identity_digest)) {
connection_or_set_identity_digest(conn, (const char*)peer_id);
tor_free(conn->nickname);
conn->nickname = tor_malloc(HEX_DIGEST_LEN+2);
conn->nickname[0] = '$';
base16_encode(conn->nickname+1, HEX_DIGEST_LEN+1,
conn->identity_digest, DIGEST_LEN);
log_info(LD_HANDSHAKE, "Connected to router %s at %s:%d without knowing "
"its key. Hoping for the best.",
conn->nickname, conn->_base.address, conn->_base.port);
/* if it's a bridge and we didn't know its identity fingerprint, now
* we do -- remember it for future attempts. */
learned_router_identity(&conn->_base.addr, conn->_base.port,
(const char*)peer_id);
}
if (tor_memneq(peer_id, conn->identity_digest, DIGEST_LEN)) {
/* I was aiming for a particular digest. I didn't get it! */
char seen[HEX_DIGEST_LEN+1];
char expected[HEX_DIGEST_LEN+1];
base16_encode(seen, sizeof(seen), (const char*)peer_id, DIGEST_LEN);
base16_encode(expected, sizeof(expected), conn->identity_digest,
DIGEST_LEN);
log_fn(severity, LD_HANDSHAKE,
"Tried connecting to router at %s:%d, but identity key was not "
"as expected: wanted %s but got %s.",
conn->_base.address, conn->_base.port, expected, seen);
entry_guard_register_connect_status(conn->identity_digest, 0, 1,
time(NULL));
control_event_or_conn_status(conn, OR_CONN_EVENT_FAILED,
END_OR_CONN_REASON_OR_IDENTITY);
if (!authdir_mode_tests_reachability(options))
control_event_bootstrap_problem(
"Unexpected identity in router certificate",
END_OR_CONN_REASON_OR_IDENTITY);
return -1;
}
if (authdir_mode_tests_reachability(options)) {
dirserv_orconn_tls_done(conn->_base.address, conn->_base.port,
(const char*)peer_id);
}
return 0;
}
/** The v1/v2 TLS handshake is finished.
*
* Make sure we are happy with the person we just handshaked with.
*
* If he initiated the connection, make sure he's not already connected,
* then initialize conn from the information in router.
*
* If all is successful, call circuit_n_conn_done() to handle events
* that have been pending on the <tls handshake completion. Also set the
* directory to be dirty (only matters if I'm an authdirserver).
*
* If this is a v2 TLS handshake, send a versions cell.
*/
static int
connection_tls_finish_handshake(or_connection_t *conn)
{
char digest_rcvd[DIGEST_LEN];
int started_here = connection_or_nonopen_was_started_here(conn);
log_debug(LD_HANDSHAKE,"%s tls handshake on %p with %s done. verifying.",
started_here?"outgoing":"incoming",
conn,
safe_str_client(conn->_base.address));
directory_set_dirty();
if (connection_or_check_valid_tls_handshake(conn, started_here,
digest_rcvd) < 0)
return -1;
circuit_build_times_network_is_live(&circ_times);
if (tor_tls_used_v1_handshake(conn->tls)) {
conn->link_proto = 1;
if (!started_here) {
connection_or_init_conn_from_address(conn, &conn->_base.addr,
conn->_base.port, digest_rcvd, 0);
}
tor_tls_block_renegotiation(conn->tls);
return connection_or_set_state_open(conn);
} else {
conn->_base.state = OR_CONN_STATE_OR_HANDSHAKING_V2;
if (connection_init_or_handshake_state(conn, started_here) < 0)
return -1;
if (!started_here) {
connection_or_init_conn_from_address(conn, &conn->_base.addr,
conn->_base.port, digest_rcvd, 0);
}
return connection_or_send_versions(conn, 0);
}
}
/**
* Called as client when initial TLS handshake is done, and we notice
* that we got a v3-handshake signalling certificate from the server.
* Set up structures, do bookkeeping, and send the versions cell.
* Return 0 on success and -1 on failure.
*/
static int
connection_or_launch_v3_or_handshake(or_connection_t *conn)
{
tor_assert(connection_or_nonopen_was_started_here(conn));
tor_assert(tor_tls_received_v3_certificate(conn->tls));
circuit_build_times_network_is_live(&circ_times);
conn->_base.state = OR_CONN_STATE_OR_HANDSHAKING_V3;
if (connection_init_or_handshake_state(conn, 1) < 0)
return -1;
return connection_or_send_versions(conn, 1);
}
/** Allocate a new connection handshake state for the connection
* <b>conn</b>. Return 0 on success, -1 on failure. */
int
connection_init_or_handshake_state(or_connection_t *conn, int started_here)
{
or_handshake_state_t *s;
if (conn->handshake_state) {
log_warn(LD_BUG, "Duplicate call to connection_init_or_handshake_state!");
return 0;
}
s = conn->handshake_state = tor_malloc_zero(sizeof(or_handshake_state_t));
s->started_here = started_here ? 1 : 0;
s->digest_sent_data = 1;
s->digest_received_data = 1;
return 0;
}
/** Free all storage held by <b>state</b>. */
void
or_handshake_state_free(or_handshake_state_t *state)
{
if (!state)
return;
crypto_digest_free(state->digest_sent);
crypto_digest_free(state->digest_received);
tor_cert_free(state->auth_cert);
tor_cert_free(state->id_cert);
memwipe(state, 0xBE, sizeof(or_handshake_state_t));
tor_free(state);
}
/**
* Remember that <b>cell</b> has been transmitted (if <b>incoming</b> is
* false) or received (if <b>incoming</b> is true) during a V3 handshake using
* <b>state</b>.
*
* (We don't record the cell, but we keep a digest of everything sent or
* received during the v3 handshake, and the client signs it in an
* authenticate cell.)
*/
void
or_handshake_state_record_cell(or_handshake_state_t *state,
const cell_t *cell,
int incoming)
{
crypto_digest_t *d, **dptr;
packed_cell_t packed;
if (incoming) {
if (!state->digest_received_data)
return;
} else {
if (!state->digest_sent_data)
return;
}
if (!incoming) {
log_warn(LD_BUG, "We shouldn't be sending any non-variable-length cells "
"while making a handshake digest. But we think we are sending "
"one with type %d.", (int)cell->command);
}
dptr = incoming ? &state->digest_received : &state->digest_sent;
if (! *dptr)
*dptr = crypto_digest256_new(DIGEST_SHA256);
d = *dptr;
/* Re-packing like this is a little inefficient, but we don't have to do
this very often at all. */
cell_pack(&packed, cell);
crypto_digest_add_bytes(d, packed.body, sizeof(packed.body));
memwipe(&packed, 0, sizeof(packed));
}
/** Remember that a variable-length <b>cell</b> has been transmitted (if
* <b>incoming</b> is false) or received (if <b>incoming</b> is true) during a
* V3 handshake using <b>state</b>.
*
* (We don't record the cell, but we keep a digest of everything sent or
* received during the v3 handshake, and the client signs it in an
* authenticate cell.)
*/
void
or_handshake_state_record_var_cell(or_handshake_state_t *state,
const var_cell_t *cell,
int incoming)
{
crypto_digest_t *d, **dptr;
char buf[VAR_CELL_HEADER_SIZE];
if (incoming) {
if (!state->digest_received_data)
return;
} else {
if (!state->digest_sent_data)
return;
}
dptr = incoming ? &state->digest_received : &state->digest_sent;
if (! *dptr)
*dptr = crypto_digest256_new(DIGEST_SHA256);
d = *dptr;
var_cell_pack_header(cell, buf);
crypto_digest_add_bytes(d, buf, sizeof(buf));
crypto_digest_add_bytes(d, (const char *)cell->payload, cell->payload_len);
memwipe(buf, 0, sizeof(buf));
}
/** Set <b>conn</b>'s state to OR_CONN_STATE_OPEN, and tell other subsystems
* as appropriate. Called when we are done with all TLS and OR handshaking.
*/
int
connection_or_set_state_open(or_connection_t *conn)
{
int started_here = connection_or_nonopen_was_started_here(conn);
time_t now = time(NULL);
conn->_base.state = OR_CONN_STATE_OPEN;
control_event_or_conn_status(conn, OR_CONN_EVENT_CONNECTED, 0);
if (started_here) {
circuit_build_times_network_is_live(&circ_times);
rep_hist_note_connect_succeeded(conn->identity_digest, now);
if (entry_guard_register_connect_status(conn->identity_digest,
1, 0, now) < 0) {
/* Close any circuits pending on this conn. We leave it in state
* 'open' though, because it didn't actually *fail* -- we just
* chose not to use it. (Otherwise
* connection_about_to_close_connection() will call a big pile of
* functions to indicate we shouldn't try it again.) */
log_debug(LD_OR, "New entry guard was reachable, but closing this "
"connection so we can retry the earlier entry guards.");
circuit_n_conn_done(conn, 0);
return -1;
}
router_set_status(conn->identity_digest, 1);
} else {
/* only report it to the geoip module if it's not a known router */
if (!router_get_by_id_digest(conn->identity_digest)) {
geoip_note_client_seen(GEOIP_CLIENT_CONNECT, &TO_CONN(conn)->addr,
now);
}
}
or_handshake_state_free(conn->handshake_state);
conn->handshake_state = NULL;
IF_HAS_BUFFEREVENT(TO_CONN(conn), {
connection_watch_events(TO_CONN(conn), READ_EVENT|WRITE_EVENT);
}) ELSE_IF_NO_BUFFEREVENT {
connection_start_reading(TO_CONN(conn));
}
circuit_n_conn_done(conn, 1); /* send the pending creates, if any. */
return 0;
}
/** Pack <b>cell</b> into wire-format, and write it onto <b>conn</b>'s outbuf.
* For cells that use or affect a circuit, this should only be called by
* connection_or_flush_from_first_active_circuit().
*/
void
connection_or_write_cell_to_buf(const cell_t *cell, or_connection_t *conn)
{
packed_cell_t networkcell;
tor_assert(cell);
tor_assert(conn);
cell_pack(&networkcell, cell);
connection_write_to_buf(networkcell.body, CELL_NETWORK_SIZE, TO_CONN(conn));
if (conn->_base.state == OR_CONN_STATE_OR_HANDSHAKING_V3)
or_handshake_state_record_cell(conn->handshake_state, cell, 0);
if (cell->command != CELL_PADDING)
conn->timestamp_last_added_nonpadding = approx_time();
}
/** Pack a variable-length <b>cell</b> into wire-format, and write it onto
* <b>conn</b>'s outbuf. Right now, this <em>DOES NOT</em> support cells that
* affect a circuit.
*/
void
connection_or_write_var_cell_to_buf(const var_cell_t *cell,
or_connection_t *conn)
{
char hdr[VAR_CELL_HEADER_SIZE];
tor_assert(cell);
tor_assert(conn);
var_cell_pack_header(cell, hdr);
connection_write_to_buf(hdr, sizeof(hdr), TO_CONN(conn));
connection_write_to_buf((char*)cell->payload,
cell->payload_len, TO_CONN(conn));
if (conn->_base.state == OR_CONN_STATE_OR_HANDSHAKING_V3)
or_handshake_state_record_var_cell(conn->handshake_state, cell, 0);
if (cell->command != CELL_PADDING)
conn->timestamp_last_added_nonpadding = approx_time();
}
/** See whether there's a variable-length cell waiting on <b>or_conn</b>'s
* inbuf. Return values as for fetch_var_cell_from_buf(). */
static int
connection_fetch_var_cell_from_buf(or_connection_t *or_conn, var_cell_t **out)
{
connection_t *conn = TO_CONN(or_conn);
IF_HAS_BUFFEREVENT(conn, {
struct evbuffer *input = bufferevent_get_input(conn->bufev);
return fetch_var_cell_from_evbuffer(input, out, or_conn->link_proto);
}) ELSE_IF_NO_BUFFEREVENT {
return fetch_var_cell_from_buf(conn->inbuf, out, or_conn->link_proto);
}
}
/** Process cells from <b>conn</b>'s inbuf.
*
* Loop: while inbuf contains a cell, pull it off the inbuf, unpack it,
* and hand it to command_process_cell().
*
* Always return 0.
*/
static int
connection_or_process_cells_from_inbuf(or_connection_t *conn)
{
var_cell_t *var_cell;
while (1) {
log_debug(LD_OR,
"%d: starting, inbuf_datalen %d (%d pending in tls object).",
conn->_base.s,(int)connection_get_inbuf_len(TO_CONN(conn)),
tor_tls_get_pending_bytes(conn->tls));
if (connection_fetch_var_cell_from_buf(conn, &var_cell)) {
if (!var_cell)
return 0; /* not yet. */
circuit_build_times_network_is_live(&circ_times);
command_process_var_cell(var_cell, conn);
var_cell_free(var_cell);
} else {
char buf[CELL_NETWORK_SIZE];
cell_t cell;
if (connection_get_inbuf_len(TO_CONN(conn))
< CELL_NETWORK_SIZE) /* whole response available? */
return 0; /* not yet */
circuit_build_times_network_is_live(&circ_times);
connection_fetch_from_buf(buf, CELL_NETWORK_SIZE, TO_CONN(conn));
/* retrieve cell info from buf (create the host-order struct from the
* network-order string) */
cell_unpack(&cell, buf);
command_process_cell(&cell, conn);
}
}
}
/** Write a destroy cell with circ ID <b>circ_id</b> and reason <b>reason</b>
* onto OR connection <b>conn</b>. Don't perform range-checking on reason:
* we may want to propagate reasons from other cells.
*
* Return 0.
*/
int
connection_or_send_destroy(circid_t circ_id, or_connection_t *conn, int reason)
{
cell_t cell;
tor_assert(conn);
memset(&cell, 0, sizeof(cell_t));
cell.circ_id = circ_id;
cell.command = CELL_DESTROY;
cell.payload[0] = (uint8_t) reason;
log_debug(LD_OR,"Sending destroy (circID %d).", circ_id);
connection_or_write_cell_to_buf(&cell, conn);
return 0;
}
/** Array of recognized link protocol versions. */
static const uint16_t or_protocol_versions[] = { 1, 2, 3 };
/** Number of versions in <b>or_protocol_versions</b>. */
static const int n_or_protocol_versions =
(int)( sizeof(or_protocol_versions)/sizeof(uint16_t) );
/** Return true iff <b>v</b> is a link protocol version that this Tor
* implementation believes it can support. */
int
is_or_protocol_version_known(uint16_t v)
{
int i;
for (i = 0; i < n_or_protocol_versions; ++i) {
if (or_protocol_versions[i] == v)
return 1;
}
return 0;
}
/** Send a VERSIONS cell on <b>conn</b>, telling the other host about the
* link protocol versions that this Tor can support.
*
* If <b>v3_plus</b>, this is part of a V3 protocol handshake, so only
* allow protocol version v3 or later. If not <b>v3_plus</b>, this is
* not part of a v3 protocol handshake, so don't allow protocol v3 or
* later.
**/
int
connection_or_send_versions(or_connection_t *conn, int v3_plus)
{
var_cell_t *cell;
int i;
int n_versions = 0;
const int min_version = v3_plus ? 3 : 0;
const int max_version = v3_plus ? UINT16_MAX : 2;
tor_assert(conn->handshake_state &&
!conn->handshake_state->sent_versions_at);
cell = var_cell_new(n_or_protocol_versions * 2);
cell->command = CELL_VERSIONS;
for (i = 0; i < n_or_protocol_versions; ++i) {
uint16_t v = or_protocol_versions[i];
if (v < min_version || v > max_version)
continue;
set_uint16(cell->payload+(2*n_versions), htons(v));
++n_versions;
}
cell->payload_len = n_versions * 2;
connection_or_write_var_cell_to_buf(cell, conn);
conn->handshake_state->sent_versions_at = time(NULL);
var_cell_free(cell);
return 0;
}
/** Send a NETINFO cell on <b>conn</b>, telling the other server what we know
* about their address, our address, and the current time. */
int
connection_or_send_netinfo(or_connection_t *conn)
{
cell_t cell;
time_t now = time(NULL);
const routerinfo_t *me;
int len;
uint8_t *out;
tor_assert(conn->handshake_state);
memset(&cell, 0, sizeof(cell_t));
cell.command = CELL_NETINFO;
/* Timestamp. */
set_uint32(cell.payload, htonl((uint32_t)now));
/* Their address. */
out = cell.payload + 4;
/* We use &conn->real_addr below, unless it hasn't yet been set. If it
* hasn't yet been set, we know that _base.addr hasn't been tampered with
* yet either. */
len = append_address_to_payload(out, !tor_addr_is_null(&conn->real_addr)
? &conn->real_addr : &conn->_base.addr);
if (len<0)
return -1;
out += len;
/* My address -- only include it if I'm a public relay, or if I'm a
* bridge and this is an incoming connection. If I'm a bridge and this
* is an outgoing connection, act like a normal client and omit it. */
if ((public_server_mode(get_options()) || !conn->is_outgoing) &&
(me = router_get_my_routerinfo())) {
tor_addr_t my_addr;
*out++ = 1; /* only one address is supported. */
tor_addr_from_ipv4h(&my_addr, me->addr);
len = append_address_to_payload(out, &my_addr);
if (len < 0)
return -1;
} else {
*out = 0;
}
conn->handshake_state->digest_sent_data = 0;
connection_or_write_cell_to_buf(&cell, conn);
return 0;
}
/** Send a CERTS cell on the connection <b>conn</b>. Return 0 on success, -1
* on failure. */
int
connection_or_send_certs_cell(or_connection_t *conn)
{
const tor_cert_t *link_cert = NULL, *id_cert = NULL;
const uint8_t *link_encoded = NULL, *id_encoded = NULL;
size_t link_len, id_len;
var_cell_t *cell;
size_t cell_len;
ssize_t pos;
int server_mode;
tor_assert(conn->_base.state == OR_CONN_STATE_OR_HANDSHAKING_V3);
if (! conn->handshake_state)
return -1;
server_mode = ! conn->handshake_state->started_here;
if (tor_tls_get_my_certs(server_mode, &link_cert, &id_cert) < 0)
return -1;
tor_cert_get_der(link_cert, &link_encoded, &link_len);
tor_cert_get_der(id_cert, &id_encoded, &id_len);
cell_len = 1 /* 1 byte: num certs in cell */ +
2 * ( 1 + 2 ) /* For each cert: 1 byte for type, 2 for length */ +
link_len + id_len;
cell = var_cell_new(cell_len);
cell->command = CELL_CERTS;
cell->payload[0] = 2;
pos = 1;
if (server_mode)
cell->payload[pos] = OR_CERT_TYPE_TLS_LINK; /* Link cert */
else
cell->payload[pos] = OR_CERT_TYPE_AUTH_1024; /* client authentication */
set_uint16(&cell->payload[pos+1], htons(link_len));
memcpy(&cell->payload[pos+3], link_encoded, link_len);
pos += 3 + link_len;
cell->payload[pos] = OR_CERT_TYPE_ID_1024; /* ID cert */
set_uint16(&cell->payload[pos+1], htons(id_len));
memcpy(&cell->payload[pos+3], id_encoded, id_len);
pos += 3 + id_len;
tor_assert(pos == (int)cell_len); /* Otherwise we just smashed the heap */
connection_or_write_var_cell_to_buf(cell, conn);
var_cell_free(cell);
return 0;
}
/** Send an AUTH_CHALLENGE cell on the connection <b>conn</b>. Return 0
* on success, -1 on failure. */
int
connection_or_send_auth_challenge_cell(or_connection_t *conn)
{
var_cell_t *cell;
uint8_t *cp;
uint8_t challenge[OR_AUTH_CHALLENGE_LEN];
tor_assert(conn->_base.state == OR_CONN_STATE_OR_HANDSHAKING_V3);
if (! conn->handshake_state)
return -1;
if (crypto_rand((char*)challenge, OR_AUTH_CHALLENGE_LEN) < 0)
return -1;
cell = var_cell_new(OR_AUTH_CHALLENGE_LEN + 4);
cell->command = CELL_AUTH_CHALLENGE;
memcpy(cell->payload, challenge, OR_AUTH_CHALLENGE_LEN);
cp = cell->payload + OR_AUTH_CHALLENGE_LEN;
set_uint16(cp, htons(1)); /* We recognize one authentication type. */
set_uint16(cp+2, htons(AUTHTYPE_RSA_SHA256_TLSSECRET));
connection_or_write_var_cell_to_buf(cell, conn);
var_cell_free(cell);
memwipe(challenge, 0, sizeof(challenge));
return 0;
}
/** Compute the main body of an AUTHENTICATE cell that a client can use
* to authenticate itself on a v3 handshake for <b>conn</b>. Write it to the
* <b>outlen</b>-byte buffer at <b>out</b>.
*
* If <b>server</b> is true, only calculate the first
* V3_AUTH_FIXED_PART_LEN bytes -- the part of the authenticator that's
* determined by the rest of the handshake, and which match the provided value
* exactly.
*
* If <b>server</b> is false and <b>signing_key</b> is NULL, calculate the
* first V3_AUTH_BODY_LEN bytes of the authenticator (that is, everything
* that should be signed), but don't actually sign it.
*
* If <b>server</b> is false and <b>signing_key</b> is provided, calculate the
* entire authenticator, signed with <b>signing_key</b>.
*
* Return the length of the cell body on success, and -1 on failure.
*/
int
connection_or_compute_authenticate_cell_body(or_connection_t *conn,
uint8_t *out, size_t outlen,
crypto_pk_t *signing_key,
int server)
{
uint8_t *ptr;
/* assert state is reasonable XXXX */
if (outlen < V3_AUTH_FIXED_PART_LEN ||
(!server && outlen < V3_AUTH_BODY_LEN))
return -1;
ptr = out;
/* Type: 8 bytes. */
memcpy(ptr, "AUTH0001", 8);
ptr += 8;
{
const tor_cert_t *id_cert=NULL, *link_cert=NULL;
const digests_t *my_digests, *their_digests;
const uint8_t *my_id, *their_id, *client_id, *server_id;
if (tor_tls_get_my_certs(0, &link_cert, &id_cert))
return -1;
my_digests = tor_cert_get_id_digests(id_cert);
their_digests = tor_cert_get_id_digests(conn->handshake_state->id_cert);
tor_assert(my_digests);
tor_assert(their_digests);
my_id = (uint8_t*)my_digests->d[DIGEST_SHA256];
their_id = (uint8_t*)their_digests->d[DIGEST_SHA256];
client_id = server ? their_id : my_id;
server_id = server ? my_id : their_id;
/* Client ID digest: 32 octets. */
memcpy(ptr, client_id, 32);
ptr += 32;
/* Server ID digest: 32 octets. */
memcpy(ptr, server_id, 32);
ptr += 32;
}
{
crypto_digest_t *server_d, *client_d;
if (server) {
server_d = conn->handshake_state->digest_sent;
client_d = conn->handshake_state->digest_received;
} else {
client_d = conn->handshake_state->digest_sent;
server_d = conn->handshake_state->digest_received;
}
/* Server log digest : 32 octets */
crypto_digest_get_digest(server_d, (char*)ptr, 32);
ptr += 32;
/* Client log digest : 32 octets */
crypto_digest_get_digest(client_d, (char*)ptr, 32);
ptr += 32;
}
{
/* Digest of cert used on TLS link : 32 octets. */
const tor_cert_t *cert = NULL;
tor_cert_t *freecert = NULL;
if (server) {
tor_tls_get_my_certs(1, &cert, NULL);
} else {
freecert = tor_tls_get_peer_cert(conn->tls);
cert = freecert;
}
if (!cert)
return -1;
memcpy(ptr, tor_cert_get_cert_digests(cert)->d[DIGEST_SHA256], 32);
if (freecert)
tor_cert_free(freecert);
ptr += 32;
}
/* HMAC of clientrandom and serverrandom using master key : 32 octets */
tor_tls_get_tlssecrets(conn->tls, ptr);
ptr += 32;
tor_assert(ptr - out == V3_AUTH_FIXED_PART_LEN);
if (server)
return V3_AUTH_FIXED_PART_LEN; // ptr-out
/* Time: 8 octets. */
{
uint64_t now = time(NULL);
if ((time_t)now < 0)
return -1;
set_uint32(ptr, htonl((uint32_t)(now>>32)));
set_uint32(ptr+4, htonl((uint32_t)now));
ptr += 8;
}
/* Nonce: 16 octets. */
crypto_rand((char*)ptr, 16);
ptr += 16;
tor_assert(ptr - out == V3_AUTH_BODY_LEN);
if (!signing_key)
return V3_AUTH_BODY_LEN; // ptr - out
{
int siglen;
char d[32];
crypto_digest256(d, (char*)out, ptr-out, DIGEST_SHA256);
siglen = crypto_pk_private_sign(signing_key,
(char*)ptr, outlen - (ptr-out),
d, 32);
if (siglen < 0)
return -1;
ptr += siglen;
tor_assert(ptr <= out+outlen);
return (int)(ptr - out);
}
}
/** Send an AUTHENTICATE cell on the connection <b>conn</b>. Return 0 on
* success, -1 on failure */
int
connection_or_send_authenticate_cell(or_connection_t *conn, int authtype)
{
var_cell_t *cell;
crypto_pk_t *pk = tor_tls_get_my_client_auth_key();
int authlen;
size_t cell_maxlen;
/* XXXX make sure we're actually supposed to send this! */
if (!pk) {
log_warn(LD_BUG, "Can't compute authenticate cell: no client auth key");
return -1;
}
if (authtype != AUTHTYPE_RSA_SHA256_TLSSECRET) {
log_warn(LD_BUG, "Tried to send authenticate cell with unknown "
"authentication type %d", authtype);
return -1;
}
cell_maxlen = 4 + /* overhead */
V3_AUTH_BODY_LEN + /* Authentication body */
crypto_pk_keysize(pk) + /* Max signature length */
16 /* add a few extra bytes just in case. */;
cell = var_cell_new(cell_maxlen);
cell->command = CELL_AUTHENTICATE;
set_uint16(cell->payload, htons(AUTHTYPE_RSA_SHA256_TLSSECRET));
/* skip over length ; we don't know that yet. */
authlen = connection_or_compute_authenticate_cell_body(conn,
cell->payload+4,
cell_maxlen-4,
pk,
0 /* not server */);
if (authlen < 0) {
log_warn(LD_BUG, "Unable to compute authenticate cell!");
var_cell_free(cell);
return -1;
}
tor_assert(authlen + 4 <= cell->payload_len);
set_uint16(cell->payload+2, htons(authlen));
cell->payload_len = authlen + 4;
connection_or_write_var_cell_to_buf(cell, conn);
var_cell_free(cell);
return 0;
}