/* * Copyright (c) 2012, The Tor Project, Inc. */
/* See LICENSE for licensing information */
/**
* \file channeltls.c
* \brief channel_t concrete subclass using or_connection_t
**/
/*
* Define this so channel.h gives us things only channel_t subclasses
* should touch.
*/
#define _TOR_CHANNEL_INTERNAL
#include "or.h"
#include "channel.h"
#include "channeltls.h"
#include "config.h"
#include "connection.h"
#include "connection_or.h"
#include "control.h"
#include "relay.h"
#include "router.h"
#include "routerlist.h"
/** How many CELL_PADDING cells have we received, ever? */
uint64_t stats_n_padding_cells_processed = 0;
/** How many CELL_VERSIONS cells have we received, ever? */
uint64_t stats_n_versions_cells_processed = 0;
/** How many CELL_NETINFO cells have we received, ever? */
uint64_t stats_n_netinfo_cells_processed = 0;
/** How many CELL_VPADDING cells have we received, ever? */
uint64_t stats_n_vpadding_cells_processed = 0;
/** How many CELL_CERTS cells have we received, ever? */
uint64_t stats_n_certs_cells_processed = 0;
/** How many CELL_AUTH_CHALLENGE cells have we received, ever? */
uint64_t stats_n_auth_challenge_cells_processed = 0;
/** How many CELL_AUTHENTICATE cells have we received, ever? */
uint64_t stats_n_authenticate_cells_processed = 0;
/** How many CELL_AUTHORIZE cells have we received, ever? */
uint64_t stats_n_authorize_cells_processed = 0;
/** Active listener, if any */
channel_listener_t *channel_tls_listener = NULL;
/* channel_tls_t method declarations */
static void channel_tls_close_method(channel_t *chan);
static const char * channel_tls_describe_transport_method(channel_t *chan);
static int
channel_tls_get_remote_addr_method(channel_t *chan, tor_addr_t *addr_out);
static const char *
channel_tls_get_remote_descr_method(channel_t *chan, int req);
static int channel_tls_has_queued_writes_method(channel_t *chan);
static int channel_tls_is_canonical_method(channel_t *chan, int req);
static int
channel_tls_matches_extend_info_method(channel_t *chan,
extend_info_t *extend_info);
static int channel_tls_matches_target_method(channel_t *chan,
const tor_addr_t *target);
static int channel_tls_write_cell_method(channel_t *chan,
cell_t *cell);
static int channel_tls_write_packed_cell_method(channel_t *chan,
packed_cell_t *packed_cell);
static int channel_tls_write_var_cell_method(channel_t *chan,
var_cell_t *var_cell);
/* channel_listener_tls_t method declarations */
static void channel_tls_listener_close_method(channel_listener_t *chan_l);
static const char *
channel_tls_listener_describe_transport_method(channel_listener_t *chan_l);
/** Handle incoming cells for the handshake stuff here rather than
* passing them on up. */
static void channel_tls_process_versions_cell(var_cell_t *cell,
channel_tls_t *tlschan);
static void channel_tls_process_netinfo_cell(cell_t *cell,
channel_tls_t *tlschan);
static void channel_tls_process_certs_cell(var_cell_t *cell,
channel_tls_t *tlschan);
static void channel_tls_process_auth_challenge_cell(var_cell_t *cell,
channel_tls_t *tlschan);
static void channel_tls_process_authenticate_cell(var_cell_t *cell,
channel_tls_t *tlschan);
static int command_allowed_before_handshake(uint8_t command);
static int enter_v3_handshake_with_cell(var_cell_t *cell,
channel_tls_t *tlschan);
/**
* Start a new TLS channel
*
* Launch a new OR connection to addr:port and expect to
* handshake with an OR with identity digest id_digest, and wrap
* it in a channel_tls_t.
*/
channel_t *
channel_tls_connect(const tor_addr_t *addr, uint16_t port,
const char *id_digest)
{
channel_tls_t *tlschan = tor_malloc_zero(sizeof(*tlschan));
channel_t *chan = TLS_CHAN_TO_BASE(tlschan);
channel_init(chan);
chan->state = CHANNEL_STATE_OPENING;
chan->close = channel_tls_close_method;
chan->describe_transport = channel_tls_describe_transport_method;
chan->get_remote_addr = channel_tls_get_remote_addr_method;
chan->get_remote_descr = channel_tls_get_remote_descr_method;
chan->has_queued_writes = channel_tls_has_queued_writes_method;
chan->is_canonical = channel_tls_is_canonical_method;
chan->matches_extend_info = channel_tls_matches_extend_info_method;
chan->matches_target = channel_tls_matches_target_method;
chan->write_cell = channel_tls_write_cell_method;
chan->write_packed_cell = channel_tls_write_packed_cell_method;
chan->write_var_cell = channel_tls_write_var_cell_method;
log_debug(LD_CHANNEL,
"In channel_tls_connect() for channel %p "
"(global id " U64_FORMAT ")",
tlschan,
U64_PRINTF_ARG(chan->global_identifier));
if (is_local_addr(addr)) channel_mark_local(chan);
channel_mark_outgoing(chan);
chan->active_circuit_pqueue = smartlist_new();
chan->active_circuit_pqueue_last_recalibrated = cell_ewma_get_tick();
/* Set up or_connection stuff */
tlschan->conn = connection_or_connect(addr, port, id_digest, tlschan);
/* connection_or_connect() will fill in tlschan->conn */
if (!(tlschan->conn)) {
chan->reason_for_closing = CHANNEL_CLOSE_FOR_ERROR;
channel_change_state(chan, CHANNEL_STATE_ERROR);
goto err;
}
log_debug(LD_CHANNEL,
"Got orconn %p for channel with global id " U64_FORMAT,
tlschan->conn, U64_PRINTF_ARG(chan->global_identifier));
goto done;
err:
smartlist_free(chan->active_circuit_pqueue);
tor_free(tlschan);
chan = NULL;
done:
/* If we got one, we should register it */
if (chan) channel_register(chan);
return chan;
}
/**
* Return the current channel_tls_t listener
*
* Returns the current channel listener for incoming TLS connections, or
* NULL if none has been established
*/
channel_listener_t *
channel_tls_get_listener(void)
{
return channel_tls_listener;
}
/**
* Start a channel_tls_t listener if necessary
*
* Return the current channel_tls_t listener, or start one if we haven't yet,
* and return that.
*/
channel_listener_t *
channel_tls_start_listener(void)
{
channel_listener_t *listener;
if (!channel_tls_listener) {
listener = tor_malloc_zero(sizeof(*listener));
channel_init_listener(listener);
listener->state = CHANNEL_LISTENER_STATE_LISTENING;
listener->close = channel_tls_listener_close_method;
listener->describe_transport =
channel_tls_listener_describe_transport_method;
channel_tls_listener = listener;
log_debug(LD_CHANNEL,
"Starting TLS channel listener %p with global id " U64_FORMAT,
listener, U64_PRINTF_ARG(listener->global_identifier));
channel_listener_register(listener);
} else listener = channel_tls_listener;
return listener;
}
/**
* Free everything on shutdown
*
* Not much to do here, since channel_free_all() takes care of a lot, but let's
* get rid of the listener.
*/
void
channel_tls_free_all(void)
{
log_debug(LD_CHANNEL,
"Shutting down TLS channels...");
if (channel_tls_listener) {
channel_listener_unregister(channel_tls_listener);
channel_listener_mark_for_close(channel_tls_listener);
channel_listener_free(channel_tls_listener);
channel_tls_listener = NULL;
}
log_debug(LD_CHANNEL,
"Done shutting down TLS channels");
}
/**
* Create a new channel around an incoming or_connection_t
*/
channel_t *
channel_tls_handle_incoming(or_connection_t *orconn)
{
channel_tls_t *tlschan = tor_malloc_zero(sizeof(*tlschan));
channel_t *chan = TLS_CHAN_TO_BASE(tlschan);
tor_assert(orconn);
tor_assert(!(orconn->chan));
channel_init(chan);
chan->state = CHANNEL_STATE_OPENING;
chan->close = channel_tls_close_method;
chan->describe_transport = channel_tls_describe_transport_method;
chan->get_remote_descr = channel_tls_get_remote_descr_method;
chan->has_queued_writes = channel_tls_has_queued_writes_method;
chan->is_canonical = channel_tls_is_canonical_method;
chan->matches_extend_info = channel_tls_matches_extend_info_method;
chan->matches_target = channel_tls_matches_target_method;
chan->write_cell = channel_tls_write_cell_method;
chan->write_packed_cell = channel_tls_write_packed_cell_method;
chan->write_var_cell = channel_tls_write_var_cell_method;
/* Link the channel and orconn to each other */
tlschan->conn = orconn;
orconn->chan = tlschan;
if (is_local_addr(&(TO_CONN(orconn)->addr))) channel_mark_local(chan);
channel_mark_incoming(chan);
chan->active_circuit_pqueue = smartlist_new();
chan->active_circuit_pqueue_last_recalibrated = cell_ewma_get_tick();
/* If we got one, we should register it */
if (chan) channel_register(chan);
return chan;
}
/********************************************
* Method implementations for channel_tls_t *
*******************************************/
/**
* Close a channel_tls_t
*
* This implements the close method for channel_tls_t
*/
static void
channel_tls_close_method(channel_t *chan)
{
channel_tls_t *tlschan = BASE_CHAN_TO_TLS(chan);
tor_assert(tlschan);
if (tlschan->conn) connection_or_close_normally(tlschan->conn, 1);
else {
/* Weird - we'll have to change the state ourselves, I guess */
log_info(LD_CHANNEL,
"Tried to close channel_tls_t %p with NULL conn",
tlschan);
channel_change_state(chan, CHANNEL_STATE_ERROR);
}
}
/**
* Describe the transport for a channel_tls_t
*
* This returns the string "TLS channel on connection " to the upper
* layer.
*/
static const char *
channel_tls_describe_transport_method(channel_t *chan)
{
static char *buf = NULL;
uint64_t id;
channel_tls_t *tlschan;
const char *rv = NULL;
tor_assert(chan);
tlschan = BASE_CHAN_TO_TLS(chan);
if (tlschan->conn) {
id = TO_CONN(tlschan->conn)->global_identifier;
if (buf) tor_free(buf);
tor_asprintf(&buf,
"TLS channel (connection " U64_FORMAT ")",
U64_PRINTF_ARG(id));
rv = buf;
} else {
rv = "TLS channel (no connection)";
}
return rv;
}
/**
* Get the remote address of a channel_tls_t
*
* This implements the get_remote_addr method for channel_tls_t; copy the
* remote endpoint of the channel to addr_out and return 1 (always
* succeeds for this transport).
*/
static int
channel_tls_get_remote_addr_method(channel_t *chan, tor_addr_t *addr_out)
{
channel_tls_t *tlschan = BASE_CHAN_TO_TLS(chan);
tor_assert(tlschan);
tor_assert(addr_out);
tor_assert(tlschan->conn);
tor_addr_copy(addr_out, &(TO_CONN(tlschan->conn)->addr));
return 1;
}
/**
* Get endpoint description of a channel_tls_t
*
* This implements the get_remote_descr method for channel_tls_t; it returns
* a text description of the remote endpoint of the channel suitable for use
* in log messages. The req parameter is 0 for the canonical address or 1 for
* the actual address seen.
*/
static const char *
channel_tls_get_remote_descr_method(channel_t *chan, int req)
{
#define MAX_DESCR_LEN 32
static char buf[MAX_DESCR_LEN + 1];
channel_tls_t *tlschan = BASE_CHAN_TO_TLS(chan);
connection_t *conn;
const char *answer = NULL;
char *addr_str;
tor_assert(tlschan);
tor_assert(tlschan->conn);
conn = TO_CONN(tlschan->conn);
switch (req) {
case 0:
/* Canonical address */
tor_snprintf(buf, MAX_DESCR_LEN + 1,
"%s:%u", conn->address, conn->port);
answer = buf;
break;
case 1:
/* Actual address */
addr_str = tor_dup_addr(&(tlschan->conn->real_addr));
tor_snprintf(buf, MAX_DESCR_LEN + 1,
"%s:%u", addr_str, conn->port);
tor_free(addr_str);
answer = buf;
break;
default:
/* Something's broken in channel.c */
tor_assert(1);
}
return answer;
}
/**
* Tell the upper layer if we have queued writes
*
* This implements the has_queued_writes method for channel_tls _t; it returns
* 1 iff we have queued writes on the outbuf of the underlying or_connection_t.
*/
static int
channel_tls_has_queued_writes_method(channel_t *chan)
{
size_t outbuf_len;
channel_tls_t *tlschan = BASE_CHAN_TO_TLS(chan);
tor_assert(tlschan);
tor_assert(tlschan->conn);
outbuf_len = connection_get_outbuf_len(TO_CONN(tlschan->conn));
return (outbuf_len > 0);
}
/**
* Tell the upper layer if we're canonical
*
* This implements the is_canonical method for channel_tls_t; if req is zero,
* it returns whether this is a canonical channel, and if it is one it returns
* whether that can be relied upon.
*/
static int
channel_tls_is_canonical_method(channel_t *chan, int req)
{
int answer = 0;
channel_tls_t *tlschan = BASE_CHAN_TO_TLS(chan);
tor_assert(tlschan);
tor_assert(tlschan->conn);
switch (req) {
case 0:
answer = tlschan->conn->is_canonical;
break;
case 1:
/*
* Is the is_canonical bit reliable? In protocols version 2 and up
* we get the canonical address from a NETINFO cell, but in older
* versions it might be based on an obsolete descriptor.
*/
answer = (tlschan->conn->link_proto >= 2);
break;
default:
/* This shouldn't happen; channel.c is broken if it does */
tor_assert(1);
}
return answer;
}
/**
* Check if we match an extend_info_t
*
* This implements the matches_extend_info method for channel_tls_t; the upper
* layer wants to know if this channel matches an extend_info_t.
*/
static int
channel_tls_matches_extend_info_method(channel_t *chan,
extend_info_t *extend_info)
{
channel_tls_t *tlschan = BASE_CHAN_TO_TLS(chan);
tor_assert(tlschan);
tor_assert(extend_info);
return (tor_addr_eq(&(extend_info->addr),
&(TO_CONN(tlschan->conn)->addr)) &&
(extend_info->port == TO_CONN(tlschan->conn)->port));
}
/**
* Check if we match a target address
*
* This implements the matches_target method for channel_tls _t; the upper
* layer wants to know if this channel matches a target address when extending
* a circuit.
*/
static int
channel_tls_matches_target_method(channel_t *chan,
const tor_addr_t *target)
{
channel_tls_t *tlschan = BASE_CHAN_TO_TLS(chan);
tor_assert(tlschan);
tor_assert(target);
tor_assert(tlschan->conn);
return tor_addr_compare(&(tlschan->conn->real_addr),
target, CMP_EXACT);
}
/**
* Write a cell to a channel_tls_t
*
* This implements the write_cell method for channel_tls_t; given a
* channel_tls_t and a cell_t, transmit the cell_t.
*/
static int
channel_tls_write_cell_method(channel_t *chan, cell_t *cell)
{
channel_tls_t *tlschan = BASE_CHAN_TO_TLS(chan);
tor_assert(tlschan);
tor_assert(cell);
tor_assert(tlschan->conn);
connection_or_write_cell_to_buf(cell, tlschan->conn);
return 1;
}
/**
* Write a packed cell to a channel_tls_t
*
* This implements the write_packed_cell method for channel_tls_t; given a
* channel_tls_t and a packed_cell_t, transmit the packed_cell_t.
*/
static int
channel_tls_write_packed_cell_method(channel_t *chan,
packed_cell_t *packed_cell)
{
channel_tls_t *tlschan = BASE_CHAN_TO_TLS(chan);
tor_assert(tlschan);
tor_assert(packed_cell);
tor_assert(tlschan->conn);
connection_write_to_buf(packed_cell->body, CELL_NETWORK_SIZE,
TO_CONN(tlschan->conn));
/* This is where the cell is finished; used to be done from relay.c */
packed_cell_free(packed_cell);
return 1;
}
/**
* Write a variable-length cell to a channel_tls_t
*
* This implements the write_var_cell method for channel_tls_t; given a
* channel_tls_t and a var_cell_t, transmit the var_cell_t.
*/
static int
channel_tls_write_var_cell_method(channel_t *chan, var_cell_t *var_cell)
{
channel_tls_t *tlschan = BASE_CHAN_TO_TLS(chan);
tor_assert(tlschan);
tor_assert(var_cell);
tor_assert(tlschan->conn);
connection_or_write_var_cell_to_buf(var_cell, tlschan->conn);
return 1;
}
/*************************************************
* Method implementations for channel_listener_t *
************************************************/
/**
* Close a channel_listener_t
*
* This implements the close method for channel_listener_t
*/
static void
channel_tls_listener_close_method(channel_listener_t *chan_l)
{
tor_assert(chan_l);
/*
* Listeners we just go ahead and change state through to CLOSED, but
* make sure to check if they're channel_tls_listener to NULL it out.
*/
if (chan_l == channel_tls_listener)
channel_tls_listener = NULL;
if (!(chan_l->state == CHANNEL_LISTENER_STATE_CLOSING ||
chan_l->state == CHANNEL_LISTENER_STATE_CLOSED ||
chan_l->state == CHANNEL_LISTENER_STATE_ERROR)) {
channel_listener_change_state(chan_l, CHANNEL_LISTENER_STATE_CLOSING);
}
if (chan_l->incoming_list) {
SMARTLIST_FOREACH_BEGIN(chan_l->incoming_list,
channel_t *, ichan) {
channel_mark_for_close(ichan);
} SMARTLIST_FOREACH_END(ichan);
smartlist_free(chan_l->incoming_list);
chan_l->incoming_list = NULL;
}
if (!(chan_l->state == CHANNEL_LISTENER_STATE_CLOSED ||
chan_l->state == CHANNEL_LISTENER_STATE_ERROR)) {
channel_listener_change_state(chan_l, CHANNEL_LISTENER_STATE_CLOSED);
}
}
/**
* Describe the transport for a channel_listener_t
*
* This returns the string "TLS channel (listening)" to the upper
* layer.
*/
static const char *
channel_tls_listener_describe_transport_method(channel_listener_t *chan_l)
{
tor_assert(chan_l);
return "TLS channel (listening)";
}
/*******************************************************
* Functions for handling events on an or_connection_t *
******************************************************/
/**
* Handle an orconn state change
*
* This function will be called by connection_or.c when the or_connection_t
* associated with this channel_tls_t changes state.
*/
void
channel_tls_handle_state_change_on_orconn(channel_tls_t *chan,
or_connection_t *conn,
uint8_t old_state,
uint8_t state)
{
channel_t *base_chan;
tor_assert(chan);
tor_assert(conn);
tor_assert(conn->chan == chan);
tor_assert(chan->conn == conn);
/* -Werror appeasement */
tor_assert(old_state == old_state);
base_chan = TLS_CHAN_TO_BASE(chan);
/* Make sure the base connection state makes sense - shouldn't be error,
* closed or listening. */
tor_assert(base_chan->state == CHANNEL_STATE_OPENING ||
base_chan->state == CHANNEL_STATE_OPEN ||
base_chan->state == CHANNEL_STATE_MAINT ||
base_chan->state == CHANNEL_STATE_CLOSING);
/* Did we just go to state open? */
if (state == OR_CONN_STATE_OPEN) {
/*
* We can go to CHANNEL_STATE_OPEN from CHANNEL_STATE_OPENING or
* CHANNEL_STATE_MAINT on this.
*/
channel_change_state(base_chan, CHANNEL_STATE_OPEN);
} else {
/*
* Not open, so from CHANNEL_STATE_OPEN we go to CHANNEL_STATE_MAINT,
* otherwise no change.
*/
if (base_chan->state == CHANNEL_STATE_OPEN) {
channel_change_state(base_chan, CHANNEL_STATE_MAINT);
}
}
}
/**
* Flush cells from a channel_tls_t
*
* Try to flush up to about num_cells cells, and return how many we flushed.
*/
ssize_t
channel_tls_flush_some_cells(channel_tls_t *chan, ssize_t num_cells)
{
ssize_t flushed = 0;
tor_assert(chan);
if (flushed >= num_cells) goto done;
/*
* If channel_tls_t ever buffers anything below the channel_t layer, flush
* that first here.
*/
flushed += channel_flush_some_cells(TLS_CHAN_TO_BASE(chan),
num_cells - flushed);
/*
* If channel_tls_t ever buffers anything below the channel_t layer, check
* how much we actually got and push it on down here.
*/
done:
return flushed;
}
/**
* Check if a channel_tls_t has anything to flush
*
* Return true if there is any more to flush on this channel (cells in queue
* or active circuits).
*/
int
channel_tls_more_to_flush(channel_tls_t *chan)
{
tor_assert(chan);
/*
* If channel_tls_t ever buffers anything below channel_t, the
* check for that should go here first.
*/
return channel_more_to_flush(TLS_CHAN_TO_BASE(chan));
}
#ifdef KEEP_TIMING_STATS
/**
* Timing states wrapper
*
* This is a wrapper function around the actual function that processes the
* cell that just arrived on chan. Increment *time
* by the number of microseconds used by the call to *func(cell, chan).
*/
static void
channel_tls_time_process_cell(cell_t *cell, channel_tls_t *chan, int *time,
void (*func)(cell_t *, channel_tls_t *))
{
struct timeval start, end;
long time_passed;
tor_gettimeofday(&start);
(*func)(cell, chan);
tor_gettimeofday(&end);
time_passed = tv_udiff(&start, &end) ;
if (time_passed > 10000) { /* more than 10ms */
log_debug(LD_OR,"That call just took %ld ms.",time_passed/1000);
}
if (time_passed < 0) {
log_info(LD_GENERAL,"That call took us back in time!");
time_passed = 0;
}
*time += time_passed;
}
#endif
/**
* Handle an incoming cell on a channel_tls_t
*
* This is called from connection_or.c to handle an arriving cell; it checks
* for cell types specific to the handshake for this transport protocol and
* handles them, and queues all other cells to the channel_t layer, which
* eventually will hand them off to command.c.
*/
void
channel_tls_handle_cell(cell_t *cell, or_connection_t *conn)
{
channel_tls_t *chan;
int handshaking;
#ifdef KEEP_TIMING_STATS
#define PROCESS_CELL(tp, cl, cn) STMT_BEGIN { \
++num ## tp; \
channel_tls_time_process_cell(cl, cn, & tp ## time , \
channel_tls_process_ ## tp ## _cell); \
} STMT_END
#else
#define PROCESS_CELL(tp, cl, cn) channel_tls_process_ ## tp ## _cell(cl, cn)
#endif
tor_assert(cell);
tor_assert(conn);
chan = conn->chan;
if (!chan) {
log_warn(LD_CHANNEL,
"Got a cell_t on an OR connection with no channel");
return;
}
handshaking = (TO_CONN(conn)->state != OR_CONN_STATE_OPEN);
if (conn->_base.marked_for_close)
return;
/* Reject all but VERSIONS and NETINFO when handshaking. */
/* (VERSIONS should actually be impossible; it's variable-length.) */
if (handshaking && cell->command != CELL_VERSIONS &&
cell->command != CELL_NETINFO) {
log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
"Received unexpected cell command %d in chan state %s / "
"conn state %s; closing the connection.",
(int)cell->command,
channel_state_to_string(TLS_CHAN_TO_BASE(chan)->state),
conn_state_to_string(CONN_TYPE_OR, TO_CONN(conn)->state));
connection_or_close_for_error(conn, 0);
return;
}
if (conn->_base.state == OR_CONN_STATE_OR_HANDSHAKING_V3)
or_handshake_state_record_cell(conn->handshake_state, cell, 1);
switch (cell->command) {
case CELL_PADDING:
++stats_n_padding_cells_processed;
/* do nothing */
break;
case CELL_VERSIONS:
tor_fragile_assert();
break;
case CELL_NETINFO:
++stats_n_netinfo_cells_processed;
PROCESS_CELL(netinfo, cell, chan);
break;
case CELL_CREATE:
case CELL_CREATE_FAST:
case CELL_CREATED:
case CELL_CREATED_FAST:
case CELL_RELAY:
case CELL_RELAY_EARLY:
case CELL_DESTROY:
/*
* These are all transport independent and we pass them up through the
* channel_t mechanism. They are ultimately handled in command.c.
*/
channel_queue_cell(TLS_CHAN_TO_BASE(chan), cell);
break;
default:
log_fn(LOG_INFO, LD_PROTOCOL,
"Cell of unknown type (%d) received in channeltls.c. "
"Dropping.",
cell->command);
break;
}
}
/**
* Handle an incoming variable-length cell on a channel_tls_t
*
* Process a var_cell that was just received on conn. Keep
* internal statistics about how many of each cell we've processed so far
* this second, and the total number of microseconds it took to
* process each type of cell. All the var_cell commands are handshake-
* related and live below the channel_t layer, so no variable-length
* cells ever get delivered in the current implementation, but I've left
* the mechanism in place for future use.
*/
void
channel_tls_handle_var_cell(var_cell_t *var_cell, or_connection_t *conn)
{
channel_tls_t *chan;
int handshaking;
#ifdef KEEP_TIMING_STATS
/* how many of each cell have we seen so far this second? needs better
* name. */
static int num_versions = 0, num_certs = 0;
static time_t current_second = 0; /* from previous calls to time */
time_t now = time(NULL);
if (current_second == 0) current_second = now;
if (now > current_second) { /* the second has rolled over */
/* print stats */
log_info(LD_OR,
"At end of second: %d versions (%d ms), %d certs (%d ms)",
num_versions, versions_time / ((now - current_second) * 1000),
num_certs, certs_time / ((now - current_second) * 1000));
num_versions = num_certs = 0;
versions_time = certs_time = 0;
/* remember which second it is, for next time */
current_second = now;
}
#endif
tor_assert(var_cell);
tor_assert(conn);
chan = conn->chan;
if (!chan) {
log_warn(LD_CHANNEL,
"Got a var_cell_t on an OR connection with no channel");
return;
}
handshaking = (TO_CONN(conn)->state != OR_CONN_STATE_OPEN);
if (TO_CONN(conn)->marked_for_close)
return;
switch (TO_CONN(conn)->state) {
case OR_CONN_STATE_OR_HANDSHAKING_V2:
if (var_cell->command != CELL_VERSIONS) {
log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
"Received a cell with command %d in unexpected "
"orconn state \"%s\" [%d], channel state \"%s\" [%d]; "
"closing the connection.",
(int)(var_cell->command),
conn_state_to_string(CONN_TYPE_OR, TO_CONN(conn)->state),
TO_CONN(conn)->state,
channel_state_to_string(TLS_CHAN_TO_BASE(chan)->state),
(int)(TLS_CHAN_TO_BASE(chan)->state));
/*
* The code in connection_or.c will tell channel_t to close for
* error; it will go to CHANNEL_STATE_CLOSING, and then to
* CHANNEL_STATE_ERROR when conn is closed.
*/
connection_or_close_for_error(conn, 0);
return;
}
break;
case OR_CONN_STATE_TLS_HANDSHAKING:
/* If we're using bufferevents, it's entirely possible for us to
* notice "hey, data arrived!" before we notice "hey, the handshake
* finished!" And we need to be accepting both at once to handle both
* the v2 and v3 handshakes. */
/* fall through */
case OR_CONN_STATE_TLS_SERVER_RENEGOTIATING:
if (!(command_allowed_before_handshake(var_cell->command))) {
log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
"Received a cell with command %d in unexpected "
"orconn state \"%s\" [%d], channel state \"%s\" [%d]; "
"closing the connection.",
(int)(var_cell->command),
conn_state_to_string(CONN_TYPE_OR, TO_CONN(conn)->state),
(int)(TO_CONN(conn)->state),
channel_state_to_string(TLS_CHAN_TO_BASE(chan)->state),
(int)(TLS_CHAN_TO_BASE(chan)->state));
/* see above comment about CHANNEL_STATE_ERROR */
connection_or_close_for_error(conn, 0);
return;
} else {
if (enter_v3_handshake_with_cell(var_cell, chan) < 0)
return;
}
break;
case OR_CONN_STATE_OR_HANDSHAKING_V3:
if (var_cell->command != CELL_AUTHENTICATE)
or_handshake_state_record_var_cell(conn->handshake_state, var_cell, 1);
break; /* Everything is allowed */
case OR_CONN_STATE_OPEN:
if (conn->link_proto < 3) {
log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
"Received a variable-length cell with command %d in orconn "
"state %s [%d], channel state %s [%d] with link protocol %d; "
"ignoring it.",
(int)(var_cell->command),
conn_state_to_string(CONN_TYPE_OR, TO_CONN(conn)->state),
(int)(TO_CONN(conn)->state),
channel_state_to_string(TLS_CHAN_TO_BASE(chan)->state),
(int)(TLS_CHAN_TO_BASE(chan)->state),
(int)(conn->link_proto));
return;
}
break;
default:
log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
"Received var-length cell with command %d in unexpected "
"orconn state \"%s\" [%d], channel state \"%s\" [%d]; "
"ignoring it.",
(int)(var_cell->command),
conn_state_to_string(CONN_TYPE_OR, TO_CONN(conn)->state),
(int)(TO_CONN(conn)->state),
channel_state_to_string(TLS_CHAN_TO_BASE(chan)->state),
(int)(TLS_CHAN_TO_BASE(chan)->state));
return;
}
/* Now handle the cell */
switch (var_cell->command) {
case CELL_VERSIONS:
++stats_n_versions_cells_processed;
PROCESS_CELL(versions, var_cell, chan);
break;
case CELL_VPADDING:
++stats_n_vpadding_cells_processed;
/* Do nothing */
break;
case CELL_CERTS:
++stats_n_certs_cells_processed;
PROCESS_CELL(certs, var_cell, chan);
break;
case CELL_AUTH_CHALLENGE:
++stats_n_auth_challenge_cells_processed;
PROCESS_CELL(auth_challenge, var_cell, chan);
break;
case CELL_AUTHENTICATE:
++stats_n_authenticate_cells_processed;
PROCESS_CELL(authenticate, var_cell, chan);
break;
case CELL_AUTHORIZE:
++stats_n_authorize_cells_processed;
/* Ignored so far. */
break;
default:
log_fn(LOG_INFO, LD_PROTOCOL,
"Variable-length cell of unknown type (%d) received.",
(int)(var_cell->command));
break;
}
}
/**
* Check if this cell type is allowed before the handshake is finished
*
* Return true if command is a cell command that's allowed to start a
* V3 handshake.
*/
static int
command_allowed_before_handshake(uint8_t command)
{
switch (command) {
case CELL_VERSIONS:
case CELL_VPADDING:
case CELL_AUTHORIZE:
return 1;
default:
return 0;
}
}
/**
* Start a V3 handshake on an incoming connection
*
* Called when we as a server receive an appropriate cell while waiting
* either for a cell or a TLS handshake. Set the connection's state to
* "handshaking_v3', initializes the or_handshake_state field as needed,
* and add the cell to the hash of incoming cells.)
*/
static int
enter_v3_handshake_with_cell(var_cell_t *cell, channel_tls_t *chan)
{
int started_here = 0;
tor_assert(cell);
tor_assert(chan);
tor_assert(chan->conn);
started_here = connection_or_nonopen_was_started_here(chan->conn);
tor_assert(TO_CONN(chan->conn)->state == OR_CONN_STATE_TLS_HANDSHAKING ||
TO_CONN(chan->conn)->state ==
OR_CONN_STATE_TLS_SERVER_RENEGOTIATING);
if (started_here) {
log_fn(LOG_PROTOCOL_WARN, LD_OR,
"Received a cell while TLS-handshaking, not in "
"OR_HANDSHAKING_V3, on a connection we originated.");
}
chan->conn->_base.state = OR_CONN_STATE_OR_HANDSHAKING_V3;
if (connection_init_or_handshake_state(chan->conn, started_here) < 0) {
connection_or_close_for_error(chan->conn, 0);
return -1;
}
or_handshake_state_record_var_cell(chan->conn->handshake_state, cell, 1);
return 0;
}
/**
* Process a 'versions' cell.
*
* This function is called to handle an incoming VERSIONS cell; the current
* link protocol version must be 0 to indicate that no version has yet been
* negotiated. We compare the versions in the cell to the list of versions
* we support, pick the highest version we have in common, and continue the
* negotiation from there.
*/
static void
channel_tls_process_versions_cell(var_cell_t *cell, channel_tls_t *chan)
{
int highest_supported_version = 0;
const uint8_t *cp, *end;
int started_here = 0;
tor_assert(cell);
tor_assert(chan);
tor_assert(chan->conn);
started_here = connection_or_nonopen_was_started_here(chan->conn);
if (chan->conn->link_proto != 0 ||
(chan->conn->handshake_state &&
chan->conn->handshake_state->received_versions)) {
log_fn(LOG_PROTOCOL_WARN, LD_OR,
"Received a VERSIONS cell on a connection with its version "
"already set to %d; dropping",
(int)(chan->conn->link_proto));
return;
}
switch (chan->conn->_base.state)
{
case OR_CONN_STATE_OR_HANDSHAKING_V2:
case OR_CONN_STATE_OR_HANDSHAKING_V3:
break;
case OR_CONN_STATE_TLS_HANDSHAKING:
case OR_CONN_STATE_TLS_SERVER_RENEGOTIATING:
default:
log_fn(LOG_PROTOCOL_WARN, LD_OR,
"VERSIONS cell while in unexpected state");
return;
}
tor_assert(chan->conn->handshake_state);
end = cell->payload + cell->payload_len;
for (cp = cell->payload; cp+1 < end; ++cp) {
uint16_t v = ntohs(get_uint16(cp));
if (is_or_protocol_version_known(v) && v > highest_supported_version)
highest_supported_version = v;
}
if (!highest_supported_version) {
log_fn(LOG_PROTOCOL_WARN, LD_OR,
"Couldn't find a version in common between my version list and the "
"list in the VERSIONS cell; closing connection.");
connection_or_close_for_error(chan->conn, 0);
return;
} else if (highest_supported_version == 1) {
/* Negotiating version 1 makes no sense, since version 1 has no VERSIONS
* cells. */
log_fn(LOG_PROTOCOL_WARN, LD_OR,
"Used version negotiation protocol to negotiate a v1 connection. "
"That's crazily non-compliant. Closing connection.");
connection_or_close_for_error(chan->conn, 0);
return;
} else if (highest_supported_version < 3 &&
chan->conn->_base.state == OR_CONN_STATE_OR_HANDSHAKING_V3) {
log_fn(LOG_PROTOCOL_WARN, LD_OR,
"Negotiated link protocol 2 or lower after doing a v3 TLS "
"handshake. Closing connection.");
connection_or_close_for_error(chan->conn, 0);
return;
}
chan->conn->link_proto = highest_supported_version;
chan->conn->handshake_state->received_versions = 1;
if (chan->conn->link_proto == 2) {
log_info(LD_OR,
"Negotiated version %d with %s:%d; sending NETINFO.",
highest_supported_version,
safe_str_client(chan->conn->_base.address),
chan->conn->_base.port);
if (connection_or_send_netinfo(chan->conn) < 0) {
connection_or_close_for_error(chan->conn, 0);
return;
}
} else {
const int send_versions = !started_here;
/* If we want to authenticate, send a CERTS cell */
const int send_certs = !started_here || public_server_mode(get_options());
/* If we're a relay that got a connection, ask for authentication. */
const int send_chall = !started_here && public_server_mode(get_options());
/* If our certs cell will authenticate us, we can send a netinfo cell
* right now. */
const int send_netinfo = !started_here;
const int send_any =
send_versions || send_certs || send_chall || send_netinfo;
tor_assert(chan->conn->link_proto >= 3);
log_info(LD_OR,
"Negotiated version %d with %s:%d; %s%s%s%s%s",
highest_supported_version,
safe_str_client(chan->conn->_base.address),
chan->conn->_base.port,
send_any ? "Sending cells:" : "Waiting for CERTS cell",
send_versions ? " VERSIONS" : "",
send_certs ? " CERTS" : "",
send_chall ? " AUTH_CHALLENGE" : "",
send_netinfo ? " NETINFO" : "");
#ifdef DISABLE_V3_LINKPROTO_SERVERSIDE
if (1) {
connection_or_close_normally(chan->conn, 1);
return;
}
#endif
if (send_versions) {
if (connection_or_send_versions(chan->conn, 1) < 0) {
log_warn(LD_OR, "Couldn't send versions cell");
connection_or_close_for_error(chan->conn, 0);
return;
}
}
if (send_certs) {
if (connection_or_send_certs_cell(chan->conn) < 0) {
log_warn(LD_OR, "Couldn't send certs cell");
connection_or_close_for_error(chan->conn, 0);
return;
}
}
if (send_chall) {
if (connection_or_send_auth_challenge_cell(chan->conn) < 0) {
log_warn(LD_OR, "Couldn't send auth_challenge cell");
connection_or_close_for_error(chan->conn, 0);
return;
}
}
if (send_netinfo) {
if (connection_or_send_netinfo(chan->conn) < 0) {
log_warn(LD_OR, "Couldn't send netinfo cell");
connection_or_close_for_error(chan->conn, 0);
return;
}
}
}
}
/**
* Process a 'netinfo' cell
*
* This function is called to handle an incoming NETINFO cell; read and act
* on its contents, and set the connection state to "open".
*/
static void
channel_tls_process_netinfo_cell(cell_t *cell, channel_tls_t *chan)
{
time_t timestamp;
uint8_t my_addr_type;
uint8_t my_addr_len;
const uint8_t *my_addr_ptr;
const uint8_t *cp, *end;
uint8_t n_other_addrs;
time_t now = time(NULL);
long apparent_skew = 0;
tor_addr_t my_apparent_addr = TOR_ADDR_NULL;
tor_assert(cell);
tor_assert(chan);
tor_assert(chan->conn);
if (chan->conn->link_proto < 2) {
log_fn(LOG_PROTOCOL_WARN, LD_OR,
"Received a NETINFO cell on %s connection; dropping.",
chan->conn->link_proto == 0 ? "non-versioned" : "a v1");
return;
}
if (chan->conn->_base.state != OR_CONN_STATE_OR_HANDSHAKING_V2 &&
chan->conn->_base.state != OR_CONN_STATE_OR_HANDSHAKING_V3) {
log_fn(LOG_PROTOCOL_WARN, LD_OR,
"Received a NETINFO cell on non-handshaking connection; dropping.");
return;
}
tor_assert(chan->conn->handshake_state &&
chan->conn->handshake_state->received_versions);
if (chan->conn->_base.state == OR_CONN_STATE_OR_HANDSHAKING_V3) {
tor_assert(chan->conn->link_proto >= 3);
if (chan->conn->handshake_state->started_here) {
if (!(chan->conn->handshake_state->authenticated)) {
log_fn(LOG_PROTOCOL_WARN, LD_OR,
"Got a NETINFO cell from server, "
"but no authentication. Closing the connection.");
connection_or_close_for_error(chan->conn, 0);
return;
}
} else {
/* we're the server. If the client never authenticated, we have
some housekeeping to do.*/
if (!(chan->conn->handshake_state->authenticated)) {
tor_assert(tor_digest_is_zero(
(const char*)(chan->conn->handshake_state->
authenticated_peer_id)));
channel_set_circid_type(TLS_CHAN_TO_BASE(chan), NULL);
connection_or_init_conn_from_address(chan->conn,
&(chan->conn->_base.addr),
chan->conn->_base.port,
(const char*)(chan->conn->handshake_state->
authenticated_peer_id),
0);
}
}
}
/* Decode the cell. */
timestamp = ntohl(get_uint32(cell->payload));
if (labs(now - chan->conn->handshake_state->sent_versions_at) < 180) {
apparent_skew = now - timestamp;
}
my_addr_type = (uint8_t) cell->payload[4];
my_addr_len = (uint8_t) cell->payload[5];
my_addr_ptr = (uint8_t*) cell->payload + 6;
end = cell->payload + CELL_PAYLOAD_SIZE;
cp = cell->payload + 6 + my_addr_len;
if (cp >= end) {
log_fn(LOG_PROTOCOL_WARN, LD_OR,
"Addresses too long in netinfo cell; closing connection.");
connection_or_close_for_error(chan->conn, 0);
return;
} else if (my_addr_type == RESOLVED_TYPE_IPV4 && my_addr_len == 4) {
tor_addr_from_ipv4n(&my_apparent_addr, get_uint32(my_addr_ptr));
} else if (my_addr_type == RESOLVED_TYPE_IPV6 && my_addr_len == 16) {
tor_addr_from_ipv6_bytes(&my_apparent_addr, (const char *) my_addr_ptr);
}
n_other_addrs = (uint8_t) *cp++;
while (n_other_addrs && cp < end-2) {
/* Consider all the other addresses; if any matches, this connection is
* "canonical." */
tor_addr_t addr;
const uint8_t *next =
decode_address_from_payload(&addr, cp, (int)(end-cp));
if (next == NULL) {
log_fn(LOG_PROTOCOL_WARN, LD_OR,
"Bad address in netinfo cell; closing connection.");
connection_or_close_for_error(chan->conn, 0);
return;
}
if (tor_addr_eq(&addr, &(chan->conn->real_addr))) {
chan->conn->is_canonical = 1;
break;
}
cp = next;
--n_other_addrs;
}
/* Act on apparent skew. */
/** Warn when we get a netinfo skew with at least this value. */
#define NETINFO_NOTICE_SKEW 3600
if (labs(apparent_skew) > NETINFO_NOTICE_SKEW &&
router_get_by_id_digest(chan->conn->identity_digest)) {
char dbuf[64];
int severity;
/*XXXX be smarter about when everybody says we are skewed. */
if (router_digest_is_trusted_dir(chan->conn->identity_digest))
severity = LOG_WARN;
else
severity = LOG_INFO;
format_time_interval(dbuf, sizeof(dbuf), apparent_skew);
log_fn(severity, LD_GENERAL,
"Received NETINFO cell with skewed time from "
"server at %s:%d. It seems that our clock is %s by %s, or "
"that theirs is %s. Tor requires an accurate clock to work: "
"please check your time and date settings.",
chan->conn->_base.address,
(int)(chan->conn->_base.port),
apparent_skew > 0 ? "ahead" : "behind",
dbuf,
apparent_skew > 0 ? "behind" : "ahead");
if (severity == LOG_WARN) /* only tell the controller if an authority */
control_event_general_status(LOG_WARN,
"CLOCK_SKEW SKEW=%ld SOURCE=OR:%s:%d",
apparent_skew,
chan->conn->_base.address,
chan->conn->_base.port);
}
/* XXX maybe act on my_apparent_addr, if the source is sufficiently
* trustworthy. */
if (connection_or_set_state_open(chan->conn) < 0) {
log_fn(LOG_PROTOCOL_WARN, LD_OR,
"Got good NETINFO cell from %s:%d; but "
"was unable to make the OR connection become open.",
safe_str_client(chan->conn->_base.address),
chan->conn->_base.port);
connection_or_close_for_error(chan->conn, 0);
} else {
log_info(LD_OR,
"Got good NETINFO cell from %s:%d; OR connection is now "
"open, using protocol version %d. Its ID digest is %s. "
"Our address is apparently %s.",
safe_str_client(chan->conn->_base.address),
chan->conn->_base.port,
(int)(chan->conn->link_proto),
hex_str(TLS_CHAN_TO_BASE(chan)->identity_digest,
DIGEST_LEN),
tor_addr_is_null(&my_apparent_addr) ?
"" : fmt_and_decorate_addr(&my_apparent_addr));
}
assert_connection_ok(TO_CONN(chan->conn),time(NULL));
}
/**
* Process a CERTS cell from a channel.
*
* This function is called to process an incoming CERTS cell on a
* channel_tls_t:
*
* If the other side should not have sent us a CERTS cell, or the cell is
* malformed, or it is supposed to authenticate the TLS key but it doesn't,
* then mark the connection.
*
* If the cell has a good cert chain and we're doing a v3 handshake, then
* store the certificates in or_handshake_state. If this is the client side
* of the connection, we then authenticate the server or mark the connection.
* If it's the server side, wait for an AUTHENTICATE cell.
*/
static void
channel_tls_process_certs_cell(var_cell_t *cell, channel_tls_t *chan)
{
tor_cert_t *link_cert = NULL;
tor_cert_t *id_cert = NULL;
tor_cert_t *auth_cert = NULL;
uint8_t *ptr;
int n_certs, i;
int send_netinfo = 0;
tor_assert(cell);
tor_assert(chan);
tor_assert(chan->conn);
#define ERR(s) \
do { \
log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, \
"Received a bad CERTS cell from %s:%d: %s", \
safe_str(chan->conn->_base.address), \
chan->conn->_base.port, (s)); \
connection_or_close_for_error(chan->conn, 0); \
return; \
} while (0)
if (chan->conn->_base.state != OR_CONN_STATE_OR_HANDSHAKING_V3)
ERR("We're not doing a v3 handshake!");
if (chan->conn->link_proto < 3)
ERR("We're not using link protocol >= 3");
if (chan->conn->handshake_state->received_certs_cell)
ERR("We already got one");
if (chan->conn->handshake_state->authenticated) {
/* Should be unreachable, but let's make sure. */
ERR("We're already authenticated!");
}
if (cell->payload_len < 1)
ERR("It had no body");
if (cell->circ_id)
ERR("It had a nonzero circuit ID");
n_certs = cell->payload[0];
ptr = cell->payload + 1;
for (i = 0; i < n_certs; ++i) {
uint8_t cert_type;
uint16_t cert_len;
if (ptr + 3 > cell->payload + cell->payload_len) {
goto truncated;
}
cert_type = *ptr;
cert_len = ntohs(get_uint16(ptr+1));
if (ptr + 3 + cert_len > cell->payload + cell->payload_len) {
goto truncated;
}
if (cert_type == OR_CERT_TYPE_TLS_LINK ||
cert_type == OR_CERT_TYPE_ID_1024 ||
cert_type == OR_CERT_TYPE_AUTH_1024) {
tor_cert_t *cert = tor_cert_decode(ptr + 3, cert_len);
if (!cert) {
log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
"Received undecodable certificate in CERTS cell from %s:%d",
safe_str(chan->conn->_base.address),
chan->conn->_base.port);
} else {
if (cert_type == OR_CERT_TYPE_TLS_LINK) {
if (link_cert) {
tor_cert_free(cert);
ERR("Too many TLS_LINK certificates");
}
link_cert = cert;
} else if (cert_type == OR_CERT_TYPE_ID_1024) {
if (id_cert) {
tor_cert_free(cert);
ERR("Too many ID_1024 certificates");
}
id_cert = cert;
} else if (cert_type == OR_CERT_TYPE_AUTH_1024) {
if (auth_cert) {
tor_cert_free(cert);
ERR("Too many AUTH_1024 certificates");
}
auth_cert = cert;
} else {
tor_cert_free(cert);
}
}
}
ptr += 3 + cert_len;
continue;
truncated:
ERR("It ends in the middle of a certificate");
}
if (chan->conn->handshake_state->started_here) {
int severity;
if (! (id_cert && link_cert))
ERR("The certs we wanted were missing");
/* Okay. We should be able to check the certificates now. */
if (! tor_tls_cert_matches_key(chan->conn->tls, link_cert)) {
ERR("The link certificate didn't match the TLS public key");
}
/* Note that this warns more loudly about time and validity if we were
* _trying_ to connect to an authority, not necessarily if we _did_ connect
* to one. */
if (router_digest_is_trusted_dir(
TLS_CHAN_TO_BASE(chan)->identity_digest))
severity = LOG_WARN;
else
severity = LOG_PROTOCOL_WARN;
if (! tor_tls_cert_is_valid(severity, link_cert, id_cert, 0))
ERR("The link certificate was not valid");
if (! tor_tls_cert_is_valid(severity, id_cert, id_cert, 1))
ERR("The ID certificate was not valid");
chan->conn->handshake_state->authenticated = 1;
{
const digests_t *id_digests = tor_cert_get_id_digests(id_cert);
crypto_pk_t *identity_rcvd;
if (!id_digests)
ERR("Couldn't compute digests for key in ID cert");
identity_rcvd = tor_tls_cert_get_key(id_cert);
if (!identity_rcvd)
ERR("Internal error: Couldn't get RSA key from ID cert.");
memcpy(chan->conn->handshake_state->authenticated_peer_id,
id_digests->d[DIGEST_SHA1], DIGEST_LEN);
channel_set_circid_type(TLS_CHAN_TO_BASE(chan), identity_rcvd);
crypto_pk_free(identity_rcvd);
}
if (connection_or_client_learned_peer_id(chan->conn,
chan->conn->handshake_state->authenticated_peer_id) < 0)
ERR("Problem setting or checking peer id");
log_info(LD_OR,
"Got some good certificates from %s:%d: Authenticated it.",
safe_str(chan->conn->_base.address), chan->conn->_base.port);
chan->conn->handshake_state->id_cert = id_cert;
id_cert = NULL;
if (!public_server_mode(get_options())) {
/* If we initiated the connection and we are not a public server, we
* aren't planning to authenticate at all. At this point we know who we
* are talking to, so we can just send a netinfo now. */
send_netinfo = 1;
}
} else {
if (! (id_cert && auth_cert))
ERR("The certs we wanted were missing");
/* Remember these certificates so we can check an AUTHENTICATE cell */
if (! tor_tls_cert_is_valid(LOG_PROTOCOL_WARN, auth_cert, id_cert, 1))
ERR("The authentication certificate was not valid");
if (! tor_tls_cert_is_valid(LOG_PROTOCOL_WARN, id_cert, id_cert, 1))
ERR("The ID certificate was not valid");
log_info(LD_OR,
"Got some good certificates from %s:%d: "
"Waiting for AUTHENTICATE.",
safe_str(chan->conn->_base.address),
chan->conn->_base.port);
/* XXXX check more stuff? */
chan->conn->handshake_state->id_cert = id_cert;
chan->conn->handshake_state->auth_cert = auth_cert;
id_cert = auth_cert = NULL;
}
chan->conn->handshake_state->received_certs_cell = 1;
if (send_netinfo) {
if (connection_or_send_netinfo(chan->conn) < 0) {
log_warn(LD_OR, "Couldn't send netinfo cell");
connection_or_close_for_error(chan->conn, 0);
goto err;
}
}
err:
tor_cert_free(id_cert);
tor_cert_free(link_cert);
tor_cert_free(auth_cert);
#undef ERR
}
/**
* Process an AUTH_CHALLENGE cell from a channel_tls_t
*
* This function is called to handle an incoming AUTH_CHALLENGE cell on a
* channel_tls_t; if we weren't supposed to get one (for example, because we're
* not the originator of the channel), or it's ill-formed, or we aren't doing
* a v3 handshake, mark the channel. If the cell is well-formed but we don't
* want to authenticate, just drop it. If the cell is well-formed *and* we
* want to authenticate, send an AUTHENTICATE cell and then a NETINFO cell.
*/
static void
channel_tls_process_auth_challenge_cell(var_cell_t *cell, channel_tls_t *chan)
{
int n_types, i, use_type = -1;
uint8_t *cp;
tor_assert(cell);
tor_assert(chan);
tor_assert(chan->conn);
#define ERR(s) \
do { \
log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, \
"Received a bad AUTH_CHALLENGE cell from %s:%d: %s", \
safe_str(chan->conn->_base.address), \
chan->conn->_base.port, (s)); \
connection_or_close_for_error(chan->conn, 0); \
return; \
} while (0)
if (chan->conn->_base.state != OR_CONN_STATE_OR_HANDSHAKING_V3)
ERR("We're not currently doing a v3 handshake");
if (chan->conn->link_proto < 3)
ERR("We're not using link protocol >= 3");
if (!(chan->conn->handshake_state->started_here))
ERR("We didn't originate this connection");
if (chan->conn->handshake_state->received_auth_challenge)
ERR("We already received one");
if (!(chan->conn->handshake_state->received_certs_cell))
ERR("We haven't gotten a CERTS cell yet");
if (cell->payload_len < OR_AUTH_CHALLENGE_LEN + 2)
ERR("It was too short");
if (cell->circ_id)
ERR("It had a nonzero circuit ID");
n_types = ntohs(get_uint16(cell->payload + OR_AUTH_CHALLENGE_LEN));
if (cell->payload_len < OR_AUTH_CHALLENGE_LEN + 2 + 2*n_types)
ERR("It looks truncated");
/* Now see if there is an authentication type we can use */
cp = cell->payload+OR_AUTH_CHALLENGE_LEN + 2;
for (i = 0; i < n_types; ++i, cp += 2) {
uint16_t authtype = ntohs(get_uint16(cp));
if (authtype == AUTHTYPE_RSA_SHA256_TLSSECRET)
use_type = authtype;
}
chan->conn->handshake_state->received_auth_challenge = 1;
if (! public_server_mode(get_options())) {
/* If we're not a public server then we don't want to authenticate on a
connection we originated, and we already sent a NETINFO cell when we
got the CERTS cell. We have nothing more to do. */
return;
}
if (use_type >= 0) {
log_info(LD_OR,
"Got an AUTH_CHALLENGE cell from %s:%d: Sending "
"authentication",
safe_str(chan->conn->_base.address),
chan->conn->_base.port);
if (connection_or_send_authenticate_cell(chan->conn, use_type) < 0) {
log_warn(LD_OR,
"Couldn't send authenticate cell");
connection_or_close_for_error(chan->conn, 0);
return;
}
} else {
log_info(LD_OR,
"Got an AUTH_CHALLENGE cell from %s:%d, but we don't "
"know any of its authentication types. Not authenticating.",
safe_str(chan->conn->_base.address),
chan->conn->_base.port);
}
if (connection_or_send_netinfo(chan->conn) < 0) {
log_warn(LD_OR, "Couldn't send netinfo cell");
connection_or_close_for_error(chan->conn, 0);
return;
}
#undef ERR
}
/**
* Process an AUTHENTICATE cell from a channel_tls_t
*
* If it's ill-formed or we weren't supposed to get one or we're not doing a
* v3 handshake, then mark the connection. If it does not authenticate the
* other side of the connection successfully (because it isn't signed right,
* we didn't get a CERTS cell, etc) mark the connection. Otherwise, accept
* the identity of the router on the other side of the connection.
*/
static void
channel_tls_process_authenticate_cell(var_cell_t *cell, channel_tls_t *chan)
{
uint8_t expected[V3_AUTH_FIXED_PART_LEN];
const uint8_t *auth;
int authlen;
tor_assert(cell);
tor_assert(chan);
tor_assert(chan->conn);
#define ERR(s) \
do { \
log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, \
"Received a bad AUTHENTICATE cell from %s:%d: %s", \
safe_str(chan->conn->_base.address), \
chan->conn->_base.port, (s)); \
connection_or_close_for_error(chan->conn, 0); \
return; \
} while (0)
if (chan->conn->_base.state != OR_CONN_STATE_OR_HANDSHAKING_V3)
ERR("We're not doing a v3 handshake");
if (chan->conn->link_proto < 3)
ERR("We're not using link protocol >= 3");
if (chan->conn->handshake_state->started_here)
ERR("We originated this connection");
if (chan->conn->handshake_state->received_authenticate)
ERR("We already got one!");
if (chan->conn->handshake_state->authenticated) {
/* Should be impossible given other checks */
ERR("The peer is already authenticated");
}
if (!(chan->conn->handshake_state->received_certs_cell))
ERR("We never got a certs cell");
if (chan->conn->handshake_state->auth_cert == NULL)
ERR("We never got an authentication certificate");
if (chan->conn->handshake_state->id_cert == NULL)
ERR("We never got an identity certificate");
if (cell->payload_len < 4)
ERR("Cell was way too short");
auth = cell->payload;
{
uint16_t type = ntohs(get_uint16(auth));
uint16_t len = ntohs(get_uint16(auth+2));
if (4 + len > cell->payload_len)
ERR("Authenticator was truncated");
if (type != AUTHTYPE_RSA_SHA256_TLSSECRET)
ERR("Authenticator type was not recognized");
auth += 4;
authlen = len;
}
if (authlen < V3_AUTH_BODY_LEN + 1)
ERR("Authenticator was too short");
if (connection_or_compute_authenticate_cell_body(
chan->conn, expected, sizeof(expected), NULL, 1) < 0)
ERR("Couldn't compute expected AUTHENTICATE cell body");
if (tor_memneq(expected, auth, sizeof(expected)))
ERR("Some field in the AUTHENTICATE cell body was not as expected");
{
crypto_pk_t *pk = tor_tls_cert_get_key(
chan->conn->handshake_state->auth_cert);
char d[DIGEST256_LEN];
char *signed_data;
size_t keysize;
int signed_len;
if (!pk)
ERR("Internal error: couldn't get RSA key from AUTH cert.");
crypto_digest256(d, (char*)auth, V3_AUTH_BODY_LEN, DIGEST_SHA256);
keysize = crypto_pk_keysize(pk);
signed_data = tor_malloc(keysize);
signed_len = crypto_pk_public_checksig(pk, signed_data, keysize,
(char*)auth + V3_AUTH_BODY_LEN,
authlen - V3_AUTH_BODY_LEN);
crypto_pk_free(pk);
if (signed_len < 0) {
tor_free(signed_data);
ERR("Signature wasn't valid");
}
if (signed_len < DIGEST256_LEN) {
tor_free(signed_data);
ERR("Not enough data was signed");
}
/* Note that we deliberately allow *more* than DIGEST256_LEN bytes here,
* in case they're later used to hold a SHA3 digest or something. */
if (tor_memneq(signed_data, d, DIGEST256_LEN)) {
tor_free(signed_data);
ERR("Signature did not match data to be signed.");
}
tor_free(signed_data);
}
/* Okay, we are authenticated. */
chan->conn->handshake_state->received_authenticate = 1;
chan->conn->handshake_state->authenticated = 1;
chan->conn->handshake_state->digest_received_data = 0;
{
crypto_pk_t *identity_rcvd =
tor_tls_cert_get_key(chan->conn->handshake_state->id_cert);
const digests_t *id_digests =
tor_cert_get_id_digests(chan->conn->handshake_state->id_cert);
/* This must exist; we checked key type when reading the cert. */
tor_assert(id_digests);
memcpy(chan->conn->handshake_state->authenticated_peer_id,
id_digests->d[DIGEST_SHA1], DIGEST_LEN);
channel_set_circid_type(TLS_CHAN_TO_BASE(chan), identity_rcvd);
crypto_pk_free(identity_rcvd);
connection_or_init_conn_from_address(chan->conn,
&(chan->conn->_base.addr),
chan->conn->_base.port,
(const char*)(chan->conn->handshake_state->
authenticated_peer_id),
0);
log_info(LD_OR,
"Got an AUTHENTICATE cell from %s:%d: Looks good.",
safe_str(chan->conn->_base.address),
chan->conn->_base.port);
}
#undef ERR
}