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cb083b5d3e
tor/src/or/channeltls.c
David Goulet 6b1dba214d cmux: Make EWMA policy mandatory 
To achieve this, a default value for the CircuitPriorityHalflife option was
needed. We still look in the options and then the consensus but in case no
value can be found, the default CircuitPriorityHalflifeMsec=30000 is used. It
it the value we've been using since 0.2.4.4-alpha.

This means that EWMA, our only policy, can not be disabled anymore fallbacking
to the round robin algorithm. Unneeded code to control that is removed in this
commit.

Part of #25268

Signed-off-by: David Goulet <dgoulet@torproject.org>
2018-02-15 13:45:21 -05:00

2449 lines
80 KiB
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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();
/* We only have one policy for now so always set it to EWMA. */
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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