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a7440d9c9d
tor/src/or/channeltls.c
Roger Dingledine a7440d9c9d more fixes for typos, grammar, whitespace, etc 
some of these ought to have been noticed by the "misspell" tool,
so if anybody is debugging it, here are some bug reports :)
2018-02-07 12:22:29 -05:00

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/* * Copyright (c) 2012-2017, The Tor Project, Inc. */
/* See LICENSE for licensing information */
/**
* \file channeltls.c
*
* \brief A concrete subclass of channel_t using or_connection_t to transfer
* cells between Tor instances.
*
* This module fills in the various function pointers in channel_t, to
* implement the channel_tls_t channels as used in Tor today. These channels
* are created from channel_tls_connect() and
* channel_tls_handle_incoming(). Each corresponds 1:1 to or_connection_t
* object, as implemented in connection_or.c. These channels transmit cells
* to the underlying or_connection_t by calling
* connection_or_write_*_cell_to_buf(), and receive cells from the underlying
* or_connection_t when connection_or_process_cells_from_inbuf() calls
* channel_tls_handle_*_cell().
*
* Here we also implement the server (responder) side of the v3+ Tor link
* handshake, which uses CERTS and AUTHENTICATE cell to negotiate versions,
* exchange expected and observed IP and time information, and bootstrap a
* level of authentication higher than we have gotten on the raw TLS
* handshake.
*
* NOTE: Since there is currently only one type of channel, there are probably
* more than a few cases where functionality that is currently in
* channeltls.c, connection_or.c, and channel.c ought to be divided up
* differently. The right time to do this is probably whenever we introduce
* our next channel type.
**/
/*
* Define this so channel.h gives us things only channel_t subclasses
* should touch.
*/
#define TOR_CHANNEL_INTERNAL_
#define CHANNELTLS_PRIVATE
#include "or.h"
#include "channel.h"
#include "channeltls.h"
#include "circuitmux.h"
#include "circuitmux_ewma.h"
#include "command.h"
#include "config.h"
#include "connection.h"
#include "connection_or.h"
#include "control.h"
#include "entrynodes.h"
#include "link_handshake.h"
#include "relay.h"
#include "rephist.h"
#include "router.h"
#include "routerlist.h"
#include "scheduler.h"
#include "torcert.h"
#include "networkstatus.h"
#include "channelpadding_negotiation.h"
#include "channelpadding.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 */
static 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 void channel_tls_free_method(channel_t *chan);
static double channel_tls_get_overhead_estimate_method(channel_t *chan);
static int
channel_tls_get_remote_addr_method(channel_t *chan, tor_addr_t *addr_out);
static int
channel_tls_get_transport_name_method(channel_t *chan, char **transport_out);
static const char *
channel_tls_get_remote_descr_method(channel_t *chan, int flags);
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_num_cells_writeable_method(channel_t *chan);
static size_t channel_tls_num_bytes_queued_method(channel_t *chan);
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 int command_allowed_before_handshake(uint8_t command);
static int enter_v3_handshake_with_cell(var_cell_t *cell,
channel_tls_t *tlschan);
static void channel_tls_process_padding_negotiate_cell(cell_t *cell,
channel_tls_t *chan);
/**
* Do parts of channel_tls_t initialization common to channel_tls_connect()
* and channel_tls_handle_incoming().
*/
STATIC void
channel_tls_common_init(channel_tls_t *tlschan)
{
channel_t *chan;
tor_assert(tlschan);
chan = &(tlschan->base_);
channel_init(chan);
chan->magic = TLS_CHAN_MAGIC;
chan->state = CHANNEL_STATE_OPENING;
chan->close = channel_tls_close_method;
chan->describe_transport = channel_tls_describe_transport_method;
chan->free_fn = channel_tls_free_method;
chan->get_overhead_estimate = channel_tls_get_overhead_estimate_method;
chan->get_remote_addr = channel_tls_get_remote_addr_method;
chan->get_remote_descr = channel_tls_get_remote_descr_method;
chan->get_transport_name = channel_tls_get_transport_name_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->num_bytes_queued = channel_tls_num_bytes_queued_method;
chan->num_cells_writeable = channel_tls_num_cells_writeable_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;
chan->cmux = circuitmux_alloc();
if (cell_ewma_enabled()) {
circuitmux_set_policy(chan->cmux, &ewma_policy);
}
}
/**
* Start a new TLS channel
*
* 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>, 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,
const ed25519_public_key_t *ed_id)
{
channel_tls_t *tlschan = tor_malloc_zero(sizeof(*tlschan));
channel_t *chan = &(tlschan->base_);
channel_tls_common_init(tlschan);
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)) {
log_debug(LD_CHANNEL,
"Marking new outgoing channel " U64_FORMAT " at %p as local",
U64_PRINTF_ARG(chan->global_identifier), chan);
channel_mark_local(chan);
} else {
log_debug(LD_CHANNEL,
"Marking new outgoing channel " U64_FORMAT " at %p as remote",
U64_PRINTF_ARG(chan->global_identifier), chan);
channel_mark_remote(chan);
}
channel_mark_outgoing(chan);
/* Set up or_connection stuff */
tlschan->conn = connection_or_connect(addr, port, id_digest, ed_id, 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:
circuitmux_free(chan->cmux);
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)
{
channel_listener_t *old_listener = NULL;
log_debug(LD_CHANNEL,
"Shutting down TLS channels...");
if (channel_tls_listener) {
/*
* When we close it, channel_tls_listener will get nulled out, so save
* a pointer so we can free it.
*/
old_listener = channel_tls_listener;
log_debug(LD_CHANNEL,
"Closing channel_tls_listener with ID " U64_FORMAT
" at %p.",
U64_PRINTF_ARG(old_listener->global_identifier),
old_listener);
channel_listener_unregister(old_listener);
channel_listener_mark_for_close(old_listener);
channel_listener_free(old_listener);
tor_assert(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 = &(tlschan->base_);
tor_assert(orconn);
tor_assert(!(orconn->chan));
channel_tls_common_init(tlschan);
/* Link the channel and orconn to each other */
tlschan->conn = orconn;
orconn->chan = tlschan;
if (is_local_addr(&(TO_CONN(orconn)->addr))) {
log_debug(LD_CHANNEL,
"Marking new incoming channel " U64_FORMAT " at %p as local",
U64_PRINTF_ARG(chan->global_identifier), chan);
channel_mark_local(chan);
} else {
log_debug(LD_CHANNEL,
"Marking new incoming channel " U64_FORMAT " at %p as remote",
U64_PRINTF_ARG(chan->global_identifier), chan);
channel_mark_remote(chan);
}
channel_mark_incoming(chan);
/* Register it */
channel_register(chan);
return chan;
}
/*********
* Casts *
********/
/**
* Cast a channel_tls_t to a channel_t.
*/
channel_t *
channel_tls_to_base(channel_tls_t *tlschan)
{
if (!tlschan) return NULL;
return &(tlschan->base_);
}
/**
* Cast a channel_t to a channel_tls_t, with appropriate type-checking
* asserts.
*/
channel_tls_t *
channel_tls_from_base(channel_t *chan)
{
if (!chan) return NULL;
tor_assert(chan->magic == TLS_CHAN_MAGIC);
return (channel_tls_t *)(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 <id>" 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;
}
/**
* Free a channel_tls_t
*
* This is called by the generic channel layer when freeing a channel_tls_t;
* this happens either on a channel which has already reached
* CHANNEL_STATE_CLOSED or CHANNEL_STATE_ERROR from channel_run_cleanup() or
* on shutdown from channel_free_all(). In the latter case we might still
* have an orconn active (which connection_free_all() will get to later),
* so we should null out its channel pointer now.
*/
static void
channel_tls_free_method(channel_t *chan)
{
channel_tls_t *tlschan = BASE_CHAN_TO_TLS(chan);
tor_assert(tlschan);
if (tlschan->conn) {
tlschan->conn->chan = NULL;
tlschan->conn = NULL;
}
}
/**
* Get an estimate of the average TLS overhead for the upper layer
*/
static double
channel_tls_get_overhead_estimate_method(channel_t *chan)
{
double overhead = 1.0;
channel_tls_t *tlschan = BASE_CHAN_TO_TLS(chan);
tor_assert(tlschan);
tor_assert(tlschan->conn);
/* Just return 1.0f if we don't have sensible data */
if (tlschan->conn->bytes_xmitted > 0 &&
tlschan->conn->bytes_xmitted_by_tls >=
tlschan->conn->bytes_xmitted) {
overhead = ((double)(tlschan->conn->bytes_xmitted_by_tls)) /
((double)(tlschan->conn->bytes_xmitted));
/*
* Never estimate more than 2.0; otherwise we get silly large estimates
* at the very start of a new TLS connection.
*/
if (overhead > 2.0)
overhead = 2.0;
}
log_debug(LD_CHANNEL,
"Estimated overhead ratio for TLS chan " U64_FORMAT " is %f",
U64_PRINTF_ARG(chan->global_identifier), overhead);
return overhead;
}
/**
* 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)
{
int rv = 0;
channel_tls_t *tlschan = BASE_CHAN_TO_TLS(chan);
tor_assert(tlschan);
tor_assert(addr_out);
if (tlschan->conn) {
tor_addr_copy(addr_out, &(tlschan->conn->real_addr));
rv = 1;
} else tor_addr_make_unspec(addr_out);
return rv;
}
/**
* Get the name of the pluggable transport used by a channel_tls_t.
*
* This implements the get_transport_name for channel_tls_t. If the
* channel uses a pluggable transport, copy its name to
* <b>transport_out</b> and return 0. If the channel did not use a
* pluggable transport, return -1. */
static int
channel_tls_get_transport_name_method(channel_t *chan, char **transport_out)
{
channel_tls_t *tlschan = BASE_CHAN_TO_TLS(chan);
tor_assert(tlschan);
tor_assert(transport_out);
tor_assert(tlschan->conn);
if (!tlschan->conn->ext_or_transport)
return -1;
*transport_out = tor_strdup(tlschan->conn->ext_or_transport);
return 0;
}
/**
* 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 flags)
{
#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);
if (tlschan->conn) {
conn = TO_CONN(tlschan->conn);
switch (flags) {
case 0:
/* Canonical address with port*/
tor_snprintf(buf, MAX_DESCR_LEN + 1,
"%s:%u", conn->address, conn->port);
answer = buf;
break;
case GRD_FLAG_ORIGINAL:
/* Actual address with port */
addr_str = tor_addr_to_str_dup(&(tlschan->conn->real_addr));
tor_snprintf(buf, MAX_DESCR_LEN + 1,
"%s:%u", addr_str, conn->port);
tor_free(addr_str);
answer = buf;
break;
case GRD_FLAG_ADDR_ONLY:
/* Canonical address, no port */
strlcpy(buf, conn->address, sizeof(buf));
answer = buf;
break;
case GRD_FLAG_ORIGINAL|GRD_FLAG_ADDR_ONLY:
/* Actual address, no port */
addr_str = tor_addr_to_str_dup(&(tlschan->conn->real_addr));
strlcpy(buf, addr_str, sizeof(buf));
tor_free(addr_str);
answer = buf;
break;
default:
/* Something's broken in channel.c */
tor_assert_nonfatal_unreached_once();
}
} else {
strlcpy(buf, "(No connection)", sizeof(buf));
answer = buf;
}
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);
if (!(tlschan->conn)) {
log_info(LD_CHANNEL,
"something called has_queued_writes on a tlschan "
"(%p with ID " U64_FORMAT " but no conn",
chan, U64_PRINTF_ARG(chan->global_identifier));
}
outbuf_len = (tlschan->conn != NULL) ?
connection_get_outbuf_len(TO_CONN(tlschan->conn)) :
0;
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);
if (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_nonfatal_unreached_once();
}
}
/* else return 0 for tlschan->conn == NULL */
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);
/* Never match if we have no conn */
if (!(tlschan->conn)) {
log_info(LD_CHANNEL,
"something called matches_extend_info on a tlschan "
"(%p with ID " U64_FORMAT " but no conn",
chan, U64_PRINTF_ARG(chan->global_identifier));
return 0;
}
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; return true iff we do.
*
* 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);
/* Never match if we have no conn */
if (!(tlschan->conn)) {
log_info(LD_CHANNEL,
"something called matches_target on a tlschan "
"(%p with ID " U64_FORMAT " but no conn",
chan, U64_PRINTF_ARG(chan->global_identifier));
return 0;
}
/* real_addr is the address this connection came from.
* base_.addr is updated by connection_or_init_conn_from_address()
* to be the address in the descriptor. It may be tempting to
* allow either address to be allowed, but if we did so, it would
* enable someone who steals a relay's keys to impersonate/MITM it
* from anywhere on the Internet! (Because they could make long-lived
* TLS connections from anywhere to all relays, and wait for them to
* be used for extends).
*/
return tor_addr_eq(&(tlschan->conn->real_addr), target);
}
/**
* Tell the upper layer how many bytes we have queued and not yet
* sent.
*/
static size_t
channel_tls_num_bytes_queued_method(channel_t *chan)
{
channel_tls_t *tlschan = BASE_CHAN_TO_TLS(chan);
tor_assert(tlschan);
tor_assert(tlschan->conn);
return connection_get_outbuf_len(TO_CONN(tlschan->conn));
}
/**
* Tell the upper layer how many cells we can accept to write
*
* This implements the num_cells_writeable method for channel_tls_t; it
* returns an estimate of the number of cells we can accept with
* channel_tls_write_*_cell().
*/
static int
channel_tls_num_cells_writeable_method(channel_t *chan)
{
size_t outbuf_len;
ssize_t n;
channel_tls_t *tlschan = BASE_CHAN_TO_TLS(chan);
size_t cell_network_size;
tor_assert(tlschan);
tor_assert(tlschan->conn);
cell_network_size = get_cell_network_size(tlschan->conn->wide_circ_ids);
outbuf_len = connection_get_outbuf_len(TO_CONN(tlschan->conn));
/* Get the number of cells */
n = CEIL_DIV(OR_CONN_HIGHWATER - outbuf_len, cell_network_size);
if (n < 0) n = 0;
#if SIZEOF_SIZE_T > SIZEOF_INT
if (n > INT_MAX) n = INT_MAX;
#endif
return (int)n;
}
/**
* 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);
int written = 0;
tor_assert(tlschan);
tor_assert(cell);
if (tlschan->conn) {
connection_or_write_cell_to_buf(cell, tlschan->conn);
++written;
} else {
log_info(LD_CHANNEL,
"something called write_cell on a tlschan "
"(%p with ID " U64_FORMAT " but no conn",
chan, U64_PRINTF_ARG(chan->global_identifier));
}
return written;
}
/**
* 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.
*
* Return 0 on success or negative value on error. The caller must free the
* packed cell.
*/
static int
channel_tls_write_packed_cell_method(channel_t *chan,
packed_cell_t *packed_cell)
{
tor_assert(chan);
channel_tls_t *tlschan = BASE_CHAN_TO_TLS(chan);
size_t cell_network_size = get_cell_network_size(chan->wide_circ_ids);
tor_assert(tlschan);
tor_assert(packed_cell);
if (tlschan->conn) {
connection_buf_add(packed_cell->body, cell_network_size,
TO_CONN(tlschan->conn));
} else {
log_info(LD_CHANNEL,
"something called write_packed_cell on a tlschan "
"(%p with ID " U64_FORMAT " but no conn",
chan, U64_PRINTF_ARG(chan->global_identifier));
return -1;
}
return 0;
}
/**
* 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);
int written = 0;
tor_assert(tlschan);
tor_assert(var_cell);
if (tlschan->conn) {
connection_or_write_var_cell_to_buf(var_cell, tlschan->conn);
++written;
} else {
log_info(LD_CHANNEL,
"something called write_var_cell on a tlschan "
"(%p with ID " U64_FORMAT " but no conn",
chan, U64_PRINTF_ARG(chan->global_identifier));
}
return written;
}
/*************************************************
* 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);
/* Shut the compiler up without triggering -Wtautological-compare */
(void)old_state;
base_chan = TLS_CHAN_TO_BASE(chan);
/* Make sure the base connection state makes sense - shouldn't be error
* or closed. */
tor_assert(CHANNEL_IS_OPENING(base_chan) ||
CHANNEL_IS_OPEN(base_chan) ||
CHANNEL_IS_MAINT(base_chan) ||
CHANNEL_IS_CLOSING(base_chan));
/* 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_open(base_chan);
/* We might have just become writeable; check and tell the scheduler */
if (connection_or_num_cells_writeable(conn) > 0) {
scheduler_channel_wants_writes(base_chan);
}
} else {
/*
* Not open, so from CHANNEL_STATE_OPEN we go to CHANNEL_STATE_MAINT,
* otherwise no change.
*/
if (CHANNEL_IS_OPEN(base_chan)) {
channel_change_state(base_chan, CHANNEL_STATE_MAINT);
}
}
}
#ifdef KEEP_TIMING_STATS
/**
* Timing states wrapper
*
* This is a wrapper function around the actual function that processes the
* <b>cell</b> that just arrived on <b>chan</b>. Increment <b>*time</b>
* by the number of microseconds used by the call to <b>*func(cell, chan)</b>.
*/
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 /* defined(KEEP_TIMING_STATS) */
/**
* 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.
*
* The channel layer itself decides whether the cell should be queued or
* can be handed off immediately to the upper-layer code. It is responsible
* for copying in the case that it queues; we merely pass pointers through
* which we get from connection_or_process_cells_from_inbuf().
*/
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 /* !(defined(KEEP_TIMING_STATS)) */
#define PROCESS_CELL(tp, cl, cn) channel_tls_process_ ## tp ## _cell(cl, cn)
#endif /* defined(KEEP_TIMING_STATS) */
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, conn->handshake_state, cell, 1);
/* We note that we're on the internet whenever we read a cell. This is
* a fast operation. */
entry_guards_note_internet_connectivity(get_guard_selection_info());
rep_hist_padding_count_read(PADDING_TYPE_TOTAL);
if (TLS_CHAN_TO_BASE(chan)->currently_padding)
rep_hist_padding_count_read(PADDING_TYPE_ENABLED_TOTAL);
switch (cell->command) {
case CELL_PADDING:
rep_hist_padding_count_read(PADDING_TYPE_CELL);
if (TLS_CHAN_TO_BASE(chan)->currently_padding)
rep_hist_padding_count_read(PADDING_TYPE_ENABLED_CELL);
++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_PADDING_NEGOTIATE:
++stats_n_netinfo_cells_processed;
PROCESS_CELL(padding_negotiate, 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:
case CELL_CREATE2:
case CELL_CREATED2:
/*
* These are all transport independent and we pass them up through the
* channel_t mechanism. They are ultimately handled in command.c.
*/
channel_process_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 <b>var_cell</b> that was just received on <b>conn</b>. 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.
*
* If we were handing them off to the upper layer, the channel_t queueing
* code would be responsible for memory management, and we'd just be passing
* pointers through from connection_or_process_cells_from_inbuf(). That
* caller always frees them after this function returns, so this function
* should never free var_cell.
*/
void
channel_tls_handle_var_cell(var_cell_t *var_cell, or_connection_t *conn)
{
channel_tls_t *chan;
#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 /* defined(KEEP_TIMING_STATS) */
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;
}
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. */
/* But that should be happening any longer've disabled bufferevents. */
tor_assert_nonfatal_unreached_once();
/* 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, 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;
}
/* We note that we're on the internet whenever we read a cell. This is
* a fast operation. */
entry_guards_note_internet_connectivity(get_guard_selection_info());
/* 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;
}
}
/**
* Update channel marks after connection_or.c has changed an address
*
* This is called from connection_or_init_conn_from_address() after the
* connection's _base.addr or real_addr fields have potentially been changed
* so we can recalculate the local mark. Notably, this happens when incoming
* connections are reverse-proxied and we only learn the real address of the
* remote router by looking it up in the consensus after we finish the
* handshake and know an authenticated identity digest.
*/
void
channel_tls_update_marks(or_connection_t *conn)
{
channel_t *chan = NULL;
tor_assert(conn);
tor_assert(conn->chan);
chan = TLS_CHAN_TO_BASE(conn->chan);
if (is_local_addr(&(TO_CONN(conn)->addr))) {
if (!channel_is_local(chan)) {
log_debug(LD_CHANNEL,
"Marking channel " U64_FORMAT " at %p as local",
U64_PRINTF_ARG(chan->global_identifier), chan);
channel_mark_local(chan);
}
} else {
if (channel_is_local(chan)) {
log_debug(LD_CHANNEL,
"Marking channel " U64_FORMAT " at %p as remote",
U64_PRINTF_ARG(chan->global_identifier), chan);
channel_mark_remote(chan);
}
}
}
/**
* Check if this cell type is allowed before the handshake is finished
*
* Return true if <b>command</b> 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.");
}
connection_or_block_renegotiation(chan->conn);
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,
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;
int started_here = 0;
tor_assert(cell);
tor_assert(chan);
tor_assert(chan->conn);
if ((cell->payload_len % 2) == 1) {
log_fn(LOG_PROTOCOL_WARN, LD_OR,
"Received a VERSION cell with odd payload length %d; "
"closing connection.",cell->payload_len);
connection_or_close_for_error(chan->conn, 0);
return;
}
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);
{
int i;
const uint8_t *cp = cell->payload;
for (i = 0; i < cell->payload_len / 2; ++i, cp += 2) {
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;
} else if (highest_supported_version != 2 &&
chan->conn->base_.state == OR_CONN_STATE_OR_HANDSHAKING_V2) {
/* XXXX This should eventually be a log_protocol_warn */
log_fn(LOG_WARN, LD_OR,
"Negotiated link with non-2 protocol after doing a v2 TLS "
"handshake with %s. Closing connection.",
fmt_addr(&chan->conn->base_.addr));
connection_or_close_for_error(chan->conn, 0);
return;
}
rep_hist_note_negotiated_link_proto(highest_supported_version, started_here);
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 host that got a connection, ask for authentication. */
const int send_chall = !started_here;
/* 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 /* defined(DISABLE_V3_LINKPROTO_SERVERSIDE) */
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;
}
}
/* We set this after sending the versions cell. */
/*XXXXX symbolic const.*/
TLS_CHAN_TO_BASE(chan)->wide_circ_ids =
chan->conn->link_proto >= MIN_LINK_PROTO_FOR_WIDE_CIRC_IDS;
chan->conn->wide_circ_ids = TLS_CHAN_TO_BASE(chan)->wide_circ_ids;
TLS_CHAN_TO_BASE(chan)->padding_enabled =
chan->conn->link_proto >= MIN_LINK_PROTO_FOR_CHANNEL_PADDING;
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 'padding_negotiate' cell
*
* This function is called to handle an incoming PADDING_NEGOTIATE cell;
* enable or disable padding accordingly, and read and act on its timeout
* value contents.
*/
static void
channel_tls_process_padding_negotiate_cell(cell_t *cell, channel_tls_t *chan)
{
channelpadding_negotiate_t *negotiation;
tor_assert(cell);
tor_assert(chan);
tor_assert(chan->conn);
if (chan->conn->link_proto < MIN_LINK_PROTO_FOR_CHANNEL_PADDING) {
log_fn(LOG_PROTOCOL_WARN, LD_OR,
"Received a PADDING_NEGOTIATE cell on v%d connection; dropping.",
chan->conn->link_proto);
return;
}
if (channelpadding_negotiate_parse(&negotiation, cell->payload,
CELL_PAYLOAD_SIZE) < 0) {
log_fn(LOG_PROTOCOL_WARN, LD_OR,
"Received malformed PADDING_NEGOTIATE cell on v%d connection; "
"dropping.", chan->conn->link_proto);
return;
}
channelpadding_update_padding_for_channel(TLS_CHAN_TO_BASE(chan),
negotiation);
channelpadding_negotiate_free(negotiation);
}
/**
* 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);
const routerinfo_t *me = router_get_my_routerinfo();
long apparent_skew = 0;
tor_addr_t my_apparent_addr = TOR_ADDR_NULL;
int started_here = 0;
const char *identity_digest = 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);
started_here = connection_or_nonopen_was_started_here(chan->conn);
identity_digest = chan->conn->identity_digest;
if (chan->conn->base_.state == OR_CONN_STATE_OR_HANDSHAKING_V3) {
tor_assert(chan->conn->link_proto >= 3);
if (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_rsa_peer_id)));
tor_assert(tor_mem_is_zero(
(const char*)(chan->conn->handshake_state->
authenticated_ed25519_peer_id.pubkey), 32));
/* If the client never authenticated, it's a tor client or bridge
* relay, and we must not use it for EXTEND requests (nor could we, as
* there are no authenticated peer IDs) */
channel_mark_client(TLS_CHAN_TO_BASE(chan));
channel_set_circid_type(TLS_CHAN_TO_BASE(chan), NULL,
chan->conn->link_proto < MIN_LINK_PROTO_FOR_WIDE_CIRC_IDS);
connection_or_init_conn_from_address(chan->conn,
&(chan->conn->base_.addr),
chan->conn->base_.port,
/* zero, checked above */
(const char*)(chan->conn->handshake_state->
authenticated_rsa_peer_id),
NULL, /* Ed25519 ID: Also checked as zero */
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;
/* We used to check:
* if (my_addr_len >= CELL_PAYLOAD_SIZE - 6) {
*
* This is actually never going to happen, since my_addr_len is at most 255,
* and CELL_PAYLOAD_LEN - 6 is 503. So we know that cp is < end. */
if (my_addr_type == RESOLVED_TYPE_IPV4 && my_addr_len == 4) {
tor_addr_from_ipv4n(&my_apparent_addr, get_uint32(my_addr_ptr));
if (!get_options()->BridgeRelay && me &&
get_uint32(my_addr_ptr) == htonl(me->addr)) {
TLS_CHAN_TO_BASE(chan)->is_canonical_to_peer = 1;
}
} 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);
if (!get_options()->BridgeRelay && me &&
!tor_addr_is_null(&me->ipv6_addr) &&
tor_addr_eq(&my_apparent_addr, &me->ipv6_addr)) {
TLS_CHAN_TO_BASE(chan)->is_canonical_to_peer = 1;
}
}
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;
}
/* A relay can connect from anywhere and be canonical, so
* long as it tells you from where it came. This may sound a bit
* concerning... but that's what "canonical" means: that the
* address is one that the relay itself has claimed. The relay
* might be doing something funny, but nobody else is doing a MITM
* on the relay's TCP.
*/
if (tor_addr_eq(&addr, &(chan->conn->real_addr))) {
connection_or_set_canonical(chan->conn, 1);
break;
}
cp = next;
--n_other_addrs;
}
if (me && !TLS_CHAN_TO_BASE(chan)->is_canonical_to_peer &&
channel_is_canonical(TLS_CHAN_TO_BASE(chan))) {
const char *descr =
TLS_CHAN_TO_BASE(chan)->get_remote_descr(TLS_CHAN_TO_BASE(chan), 0);
log_info(LD_OR,
"We made a connection to a relay at %s (fp=%s) but we think "
"they will not consider this connection canonical. They "
"think we are at %s, but we think its %s.",
safe_str(descr),
safe_str(hex_str(identity_digest, DIGEST_LEN)),
safe_str(tor_addr_is_null(&my_apparent_addr) ?
"<none>" : fmt_and_decorate_addr(&my_apparent_addr)),
safe_str(fmt_addr32(me->addr)));
}
/* 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 &&
(started_here ||
connection_or_digest_is_known_relay(chan->conn->identity_digest))) {
int trusted = router_digest_is_trusted_dir(chan->conn->identity_digest);
clock_skew_warning(TO_CONN(chan->conn), apparent_skew, trusted, LD_GENERAL,
"NETINFO cell", "OR");
}
/* XXX maybe act on my_apparent_addr, if the source is sufficiently
* trustworthy. */
if (! chan->conn->handshake_state->sent_netinfo) {
/* If we were prepared to authenticate, but we never got an AUTH_CHALLENGE
* cell, then we would not previously have sent a NETINFO cell. Do so
* now. */
if (connection_or_send_netinfo(chan->conn) < 0) {
connection_or_close_for_error(chan->conn, 0);
return;
}
}
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(identity_digest, DIGEST_LEN),
tor_addr_is_null(&my_apparent_addr) ?
"<none>" : fmt_and_decorate_addr(&my_apparent_addr));
}
assert_connection_ok(TO_CONN(chan->conn),time(NULL));
}
/** Types of certificates that we know how to parse from CERTS cells. Each
* type corresponds to a different encoding format. */
typedef enum cert_encoding_t {
CERT_ENCODING_UNKNOWN, /**< We don't recognize this. */
CERT_ENCODING_X509, /**< It's an RSA key, signed with RSA, encoded in x509.
* (Actually, it might not be RSA. We test that later.) */
CERT_ENCODING_ED25519, /**< It's something signed with an Ed25519 key,
* encoded asa a tor_cert_t.*/
CERT_ENCODING_RSA_CROSSCERT, /**< It's an Ed key signed with an RSA key. */
} cert_encoding_t;
/**
* Given one of the certificate type codes used in a CERTS cell,
* return the corresponding cert_encoding_t that we should use to parse
* the certificate.
*/
static cert_encoding_t
certs_cell_typenum_to_cert_type(int typenum)
{
switch (typenum) {
case CERTTYPE_RSA1024_ID_LINK:
case CERTTYPE_RSA1024_ID_ID:
case CERTTYPE_RSA1024_ID_AUTH:
return CERT_ENCODING_X509;
case CERTTYPE_ED_ID_SIGN:
case CERTTYPE_ED_SIGN_LINK:
case CERTTYPE_ED_SIGN_AUTH:
return CERT_ENCODING_ED25519;
case CERTTYPE_RSA1024_ID_EDID:
return CERT_ENCODING_RSA_CROSSCERT;
default:
return CERT_ENCODING_UNKNOWN;
}
}
/**
* 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)
{
#define MAX_CERT_TYPE_WANTED CERTTYPE_RSA1024_ID_EDID
/* These arrays will be sparse, since a cert type can be at most one
* of ed/x509 */
tor_x509_cert_t *x509_certs[MAX_CERT_TYPE_WANTED + 1];
tor_cert_t *ed_certs[MAX_CERT_TYPE_WANTED + 1];
uint8_t *rsa_ed_cc_cert = NULL;
size_t rsa_ed_cc_cert_len = 0;
int n_certs, i;
certs_cell_t *cc = NULL;
int send_netinfo = 0, started_here = 0;
memset(x509_certs, 0, sizeof(x509_certs));
memset(ed_certs, 0, sizeof(ed_certs));
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); \
goto err; \
} while (0)
/* Can't use connection_or_nonopen_was_started_here(); its conn->tls
* check looks like it breaks
* test_link_handshake_recv_certs_ok_server(). */
started_here = chan->conn->handshake_state->started_here;
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");
if (certs_cell_parse(&cc, cell->payload, cell->payload_len) < 0)
ERR("It couldn't be parsed.");
n_certs = cc->n_certs;
for (i = 0; i < n_certs; ++i) {
certs_cell_cert_t *c = certs_cell_get_certs(cc, i);
uint16_t cert_type = c->cert_type;
uint16_t cert_len = c->cert_len;
uint8_t *cert_body = certs_cell_cert_getarray_body(c);
if (cert_type > MAX_CERT_TYPE_WANTED)
continue;
const cert_encoding_t ct = certs_cell_typenum_to_cert_type(cert_type);
switch (ct) {
default:
case CERT_ENCODING_UNKNOWN:
break;
case CERT_ENCODING_X509: {
tor_x509_cert_t *x509_cert = tor_x509_cert_decode(cert_body, cert_len);
if (!x509_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 (x509_certs[cert_type]) {
tor_x509_cert_free(x509_cert);
ERR("Duplicate x509 certificate");
} else {
x509_certs[cert_type] = x509_cert;
}
}
break;
}
case CERT_ENCODING_ED25519: {
tor_cert_t *ed_cert = tor_cert_parse(cert_body, cert_len);
if (!ed_cert) {
log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
"Received undecodable Ed certificate "
"in CERTS cell from %s:%d",
safe_str(chan->conn->base_.address),
chan->conn->base_.port);
} else {
if (ed_certs[cert_type]) {
tor_cert_free(ed_cert);
ERR("Duplicate Ed25519 certificate");
} else {
ed_certs[cert_type] = ed_cert;
}
}
break;
}
case CERT_ENCODING_RSA_CROSSCERT: {
if (rsa_ed_cc_cert) {
ERR("Duplicate RSA->Ed25519 crosscert");
} else {
rsa_ed_cc_cert = tor_memdup(cert_body, cert_len);
rsa_ed_cc_cert_len = cert_len;
}
break;
}
}
}
/* Move the certificates we (might) want into the handshake_state->certs
* structure. */
tor_x509_cert_t *id_cert = x509_certs[CERTTYPE_RSA1024_ID_ID];
tor_x509_cert_t *auth_cert = x509_certs[CERTTYPE_RSA1024_ID_AUTH];
tor_x509_cert_t *link_cert = x509_certs[CERTTYPE_RSA1024_ID_LINK];
chan->conn->handshake_state->certs->auth_cert = auth_cert;
chan->conn->handshake_state->certs->link_cert = link_cert;
chan->conn->handshake_state->certs->id_cert = id_cert;
x509_certs[CERTTYPE_RSA1024_ID_ID] =
x509_certs[CERTTYPE_RSA1024_ID_AUTH] =
x509_certs[CERTTYPE_RSA1024_ID_LINK] = NULL;
tor_cert_t *ed_id_sign = ed_certs[CERTTYPE_ED_ID_SIGN];
tor_cert_t *ed_sign_link = ed_certs[CERTTYPE_ED_SIGN_LINK];
tor_cert_t *ed_sign_auth = ed_certs[CERTTYPE_ED_SIGN_AUTH];
chan->conn->handshake_state->certs->ed_id_sign = ed_id_sign;
chan->conn->handshake_state->certs->ed_sign_link = ed_sign_link;
chan->conn->handshake_state->certs->ed_sign_auth = ed_sign_auth;
ed_certs[CERTTYPE_ED_ID_SIGN] =
ed_certs[CERTTYPE_ED_SIGN_LINK] =
ed_certs[CERTTYPE_ED_SIGN_AUTH] = NULL;
chan->conn->handshake_state->certs->ed_rsa_crosscert = rsa_ed_cc_cert;
chan->conn->handshake_state->certs->ed_rsa_crosscert_len =
rsa_ed_cc_cert_len;
rsa_ed_cc_cert = NULL;
int severity;
/* 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 (started_here &&
router_digest_is_trusted_dir(TLS_CHAN_TO_BASE(chan)->identity_digest))
severity = LOG_WARN;
else
severity = LOG_PROTOCOL_WARN;
const ed25519_public_key_t *checked_ed_id = NULL;
const common_digests_t *checked_rsa_id = NULL;
or_handshake_certs_check_both(severity,
chan->conn->handshake_state->certs,
chan->conn->tls,
time(NULL),
&checked_ed_id,
&checked_rsa_id);
if (!checked_rsa_id)
ERR("Invalid certificate chain!");
if (started_here) {
/* No more information is needed. */
chan->conn->handshake_state->authenticated = 1;
chan->conn->handshake_state->authenticated_rsa = 1;
{
const common_digests_t *id_digests = checked_rsa_id;
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("Couldn't get RSA key from ID cert.");
}
memcpy(chan->conn->handshake_state->authenticated_rsa_peer_id,
id_digests->d[DIGEST_SHA1], DIGEST_LEN);
channel_set_circid_type(TLS_CHAN_TO_BASE(chan), identity_rcvd,
chan->conn->link_proto < MIN_LINK_PROTO_FOR_WIDE_CIRC_IDS);
crypto_pk_free(identity_rcvd);
}
if (checked_ed_id) {
chan->conn->handshake_state->authenticated_ed25519 = 1;
memcpy(&chan->conn->handshake_state->authenticated_ed25519_peer_id,
checked_ed_id, sizeof(ed25519_public_key_t));
}
log_debug(LD_HANDSHAKE, "calling client_learned_peer_id from "
"process_certs_cell");
if (connection_or_client_learned_peer_id(chan->conn,
chan->conn->handshake_state->authenticated_rsa_peer_id,
checked_ed_id) < 0)
ERR("Problem setting or checking peer id");
log_info(LD_HANDSHAKE,
"Got some good certificates from %s:%d: Authenticated it with "
"RSA%s",
safe_str(chan->conn->base_.address), chan->conn->base_.port,
checked_ed_id ? " and Ed25519" : "");
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 {
/* We can't call it authenticated till we see an AUTHENTICATE cell. */
log_info(LD_OR,
"Got some good RSA%s certificates from %s:%d. "
"Waiting for AUTHENTICATE.",
checked_ed_id ? " and Ed25519" : "",
safe_str(chan->conn->base_.address),
chan->conn->base_.port);
/* XXXX check more stuff? */
}
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:
for (unsigned u = 0; u < ARRAY_LENGTH(x509_certs); ++u) {
tor_x509_cert_free(x509_certs[u]);
}
for (unsigned u = 0; u < ARRAY_LENGTH(ed_certs); ++u) {
tor_cert_free(ed_certs[u]);
}
tor_free(rsa_ed_cc_cert);
certs_cell_free(cc);
#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;
auth_challenge_cell_t *ac = NULL;
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); \
goto done; \
} 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->circ_id)
ERR("It had a nonzero circuit ID");
if (auth_challenge_cell_parse(&ac, cell->payload, cell->payload_len) < 0)
ERR("It was not well-formed.");
n_types = ac->n_methods;
/* Now see if there is an authentication type we can use */
for (i = 0; i < n_types; ++i) {
uint16_t authtype = auth_challenge_cell_get_methods(ac, i);
if (authchallenge_type_is_supported(authtype)) {
if (use_type == -1 ||
authchallenge_type_is_better(authtype, use_type)) {
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. */
goto done;
}
if (use_type >= 0) {
log_info(LD_OR,
"Got an AUTH_CHALLENGE cell from %s:%d: Sending "
"authentication type %d",
safe_str(chan->conn->base_.address),
chan->conn->base_.port,
use_type);
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);
goto done;
}
} 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);
goto done;
}
done:
auth_challenge_cell_free(ac);
#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)
{
var_cell_t *expected_cell = NULL;
const uint8_t *auth;
int authlen;
int authtype;
int bodylen;
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); \
var_cell_free(expected_cell); \
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->certs->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 (! authchallenge_type_is_supported(type))
ERR("Authenticator type was not recognized");
authtype = type;
auth += 4;
authlen = len;
}
if (authlen < V3_AUTH_BODY_LEN + 1)
ERR("Authenticator was too short");
expected_cell = connection_or_compute_authenticate_cell_body(
chan->conn, authtype, NULL, NULL, 1);
if (! expected_cell)
ERR("Couldn't compute expected AUTHENTICATE cell body");
int sig_is_rsa;
if (authtype == AUTHTYPE_RSA_SHA256_TLSSECRET ||
authtype == AUTHTYPE_RSA_SHA256_RFC5705) {
bodylen = V3_AUTH_BODY_LEN;
sig_is_rsa = 1;
} else {
tor_assert(authtype == AUTHTYPE_ED25519_SHA256_RFC5705);
/* Our earlier check had better have made sure we had room
* for an ed25519 sig (inadvertently) */
tor_assert(V3_AUTH_BODY_LEN > ED25519_SIG_LEN);
bodylen = authlen - ED25519_SIG_LEN;
sig_is_rsa = 0;
}
if (expected_cell->payload_len != bodylen+4) {
ERR("Expected AUTHENTICATE cell body len not as expected.");
}
/* Length of random part. */
if (BUG(bodylen < 24)) {
// LCOV_EXCL_START
ERR("Bodylen is somehow less than 24, which should really be impossible");
// LCOV_EXCL_STOP
}
if (tor_memneq(expected_cell->payload+4, auth, bodylen-24))
ERR("Some field in the AUTHENTICATE cell body was not as expected");
if (sig_is_rsa) {
if (chan->conn->handshake_state->certs->ed_id_sign != NULL)
ERR("RSA-signed AUTHENTICATE response provided with an ED25519 cert");
if (chan->conn->handshake_state->certs->auth_cert == NULL)
ERR("We never got an RSA authentication certificate");
crypto_pk_t *pk = tor_tls_cert_get_key(
chan->conn->handshake_state->certs->auth_cert);
char d[DIGEST256_LEN];
char *signed_data;
size_t keysize;
int signed_len;
if (! pk) {
ERR("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("RSA 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);
} else {
if (chan->conn->handshake_state->certs->ed_id_sign == NULL)
ERR("We never got an Ed25519 identity certificate.");
if (chan->conn->handshake_state->certs->ed_sign_auth == NULL)
ERR("We never got an Ed25519 authentication certificate.");
const ed25519_public_key_t *authkey =
&chan->conn->handshake_state->certs->ed_sign_auth->signed_key;
ed25519_signature_t sig;
tor_assert(authlen > ED25519_SIG_LEN);
memcpy(&sig.sig, auth + authlen - ED25519_SIG_LEN, ED25519_SIG_LEN);
if (ed25519_checksig(&sig, auth, authlen - ED25519_SIG_LEN, authkey)<0) {
ERR("Ed25519 signature wasn't valid.");
}
}
/* Okay, we are authenticated. */
chan->conn->handshake_state->received_authenticate = 1;
chan->conn->handshake_state->authenticated = 1;
chan->conn->handshake_state->authenticated_rsa = 1;
chan->conn->handshake_state->digest_received_data = 0;
{
tor_x509_cert_t *id_cert = chan->conn->handshake_state->certs->id_cert;
crypto_pk_t *identity_rcvd = tor_tls_cert_get_key(id_cert);
const common_digests_t *id_digests = tor_x509_cert_get_id_digests(id_cert);
const ed25519_public_key_t *ed_identity_received = NULL;
if (! sig_is_rsa) {
chan->conn->handshake_state->authenticated_ed25519 = 1;
ed_identity_received =
&chan->conn->handshake_state->certs->ed_id_sign->signing_key;
memcpy(&chan->conn->handshake_state->authenticated_ed25519_peer_id,
ed_identity_received, sizeof(ed25519_public_key_t));
}
/* This must exist; we checked key type when reading the cert. */
tor_assert(id_digests);
memcpy(chan->conn->handshake_state->authenticated_rsa_peer_id,
id_digests->d[DIGEST_SHA1], DIGEST_LEN);
channel_set_circid_type(TLS_CHAN_TO_BASE(chan), identity_rcvd,
chan->conn->link_proto < MIN_LINK_PROTO_FOR_WIDE_CIRC_IDS);
crypto_pk_free(identity_rcvd);
log_debug(LD_HANDSHAKE,
"Calling connection_or_init_conn_from_address for %s "
" from %s, with%s ed25519 id.",
safe_str(chan->conn->base_.address),
__func__,
ed_identity_received ? "" : "out");
connection_or_init_conn_from_address(chan->conn,
&(chan->conn->base_.addr),
chan->conn->base_.port,
(const char*)(chan->conn->handshake_state->
authenticated_rsa_peer_id),
ed_identity_received,
0);
log_debug(LD_HANDSHAKE,
"Got an AUTHENTICATE cell from %s:%d, type %d: Looks good.",
safe_str(chan->conn->base_.address),
chan->conn->base_.port,
authtype);
}
var_cell_free(expected_cell);
#undef ERR
}
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