/* * Copyright (c) 2012-2015, 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. **/ /* * 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 "config.h" #include "connection.h" #include "connection_or.h" #include "control.h" #include "link_handshake.h" #include "relay.h" #include "rephist.h" #include "router.h" #include "routerlist.h" #include "scheduler.h" /** How many CELL_PADDING cells have we received, ever? */ uint64_t stats_n_padding_cells_processed = 0; /** How many CELL_VERSIONS cells have we received, ever? */ uint64_t stats_n_versions_cells_processed = 0; /** How many CELL_NETINFO cells have we received, ever? */ uint64_t stats_n_netinfo_cells_processed = 0; /** How many CELL_VPADDING cells have we received, ever? */ uint64_t stats_n_vpadding_cells_processed = 0; /** How many CELL_CERTS cells have we received, ever? */ uint64_t stats_n_certs_cells_processed = 0; /** How many CELL_AUTH_CHALLENGE cells have we received, ever? */ uint64_t stats_n_auth_challenge_cells_processed = 0; /** How many CELL_AUTHENTICATE cells have we received, ever? */ uint64_t stats_n_authenticate_cells_processed = 0; /** How many CELL_AUTHORIZE cells have we received, ever? */ uint64_t stats_n_authorize_cells_processed = 0; /** Active listener, if any */ channel_listener_t *channel_tls_listener = NULL; /* channel_tls_t method declarations */ static void channel_tls_close_method(channel_t *chan); static const char * channel_tls_describe_transport_method(channel_t *chan); static 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); /** * 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 = 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 addr:port and expect to * handshake with an OR with identity digest id_digest, and wrap * it in a channel_tls_t. */ channel_t * channel_tls_connect(const tor_addr_t *addr, uint16_t port, const char *id_digest) { channel_tls_t *tlschan = tor_malloc_zero(sizeof(*tlschan)); channel_t *chan = &(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, 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 " 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 = 1.0f; 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 > 2.0f) overhead = 2.0f; } 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, &(TO_CONN(tlschan->conn)->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 * transport_out 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_dup_addr(&(tlschan->conn->real_addr)); tor_snprintf(buf, MAX_DESCR_LEN + 1, "%s:%u", addr_str, conn->port); tor_free(addr_str); answer = buf; break; 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_dup_addr(&(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(1); } } 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(1); } } /* 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; } 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. */ static int channel_tls_write_packed_cell_method(channel_t *chan, packed_cell_t *packed_cell) { channel_tls_t *tlschan = BASE_CHAN_TO_TLS(chan); size_t cell_network_size = get_cell_network_size(chan->wide_circ_ids); int written = 0; tor_assert(tlschan); tor_assert(packed_cell); if (tlschan->conn) { connection_write_to_buf(packed_cell->body, cell_network_size, TO_CONN(tlschan->conn)); /* This is where the cell is finished; used to be done from relay.c */ packed_cell_free(packed_cell); ++written; } 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 written; } /** * 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(base_chan, CHANNEL_STATE_OPEN); /* 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 * cell that just arrived on chan. Increment *time * by the number of microseconds used by the call to *func(cell, chan). */ static void channel_tls_time_process_cell(cell_t *cell, channel_tls_t *chan, int *time, void (*func)(cell_t *, channel_tls_t *)) { struct timeval start, end; long time_passed; tor_gettimeofday(&start); (*func)(cell, chan); tor_gettimeofday(&end); time_passed = tv_udiff(&start, &end) ; if (time_passed > 10000) { /* more than 10ms */ log_debug(LD_OR,"That call just took %ld ms.",time_passed/1000); } if (time_passed < 0) { log_info(LD_GENERAL,"That call took us back in time!"); time_passed = 0; } *time += time_passed; } #endif /** * Handle an incoming cell on a channel_tls_t * * This is called from connection_or.c to handle an arriving cell; it checks * for cell types specific to the handshake for this transport protocol and * handles them, and queues all other cells to the channel_t layer, which * eventually will hand them off to command.c. */ void channel_tls_handle_cell(cell_t *cell, or_connection_t *conn) { channel_tls_t *chan; int handshaking; #ifdef KEEP_TIMING_STATS #define PROCESS_CELL(tp, cl, cn) STMT_BEGIN { \ ++num ## tp; \ channel_tls_time_process_cell(cl, cn, & tp ## time , \ channel_tls_process_ ## tp ## _cell); \ } STMT_END #else #define PROCESS_CELL(tp, cl, cn) channel_tls_process_ ## tp ## _cell(cl, cn) #endif tor_assert(cell); tor_assert(conn); chan = conn->chan; if (!chan) { log_warn(LD_CHANNEL, "Got a cell_t on an OR connection with no channel"); return; } handshaking = (TO_CONN(conn)->state != OR_CONN_STATE_OPEN); if (conn->base_.marked_for_close) return; /* Reject all but VERSIONS and NETINFO when handshaking. */ /* (VERSIONS should actually be impossible; it's variable-length.) */ if (handshaking && cell->command != CELL_VERSIONS && cell->command != CELL_NETINFO) { log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, "Received unexpected cell command %d in chan state %s / " "conn state %s; closing the connection.", (int)cell->command, channel_state_to_string(TLS_CHAN_TO_BASE(chan)->state), conn_state_to_string(CONN_TYPE_OR, TO_CONN(conn)->state)); connection_or_close_for_error(conn, 0); return; } if (conn->base_.state == OR_CONN_STATE_OR_HANDSHAKING_V3) or_handshake_state_record_cell(conn, conn->handshake_state, cell, 1); switch (cell->command) { case CELL_PADDING: ++stats_n_padding_cells_processed; /* do nothing */ break; case CELL_VERSIONS: tor_fragile_assert(); break; case CELL_NETINFO: ++stats_n_netinfo_cells_processed; PROCESS_CELL(netinfo, cell, chan); break; case CELL_CREATE: case CELL_CREATE_FAST: case CELL_CREATED: case CELL_CREATED_FAST: case CELL_RELAY: case CELL_RELAY_EARLY: case CELL_DESTROY: 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_queue_cell(TLS_CHAN_TO_BASE(chan), cell); break; default: log_fn(LOG_INFO, LD_PROTOCOL, "Cell of unknown type (%d) received in channeltls.c. " "Dropping.", cell->command); break; } } /** * Handle an incoming variable-length cell on a channel_tls_t * * Process a var_cell that was just received on conn. Keep * internal statistics about how many of each cell we've processed so far * this second, and the total number of microseconds it took to * process each type of cell. All the var_cell commands are handshake- * related and live below the channel_t layer, so no variable-length * cells ever get delivered in the current implementation, but I've left * the mechanism in place for future use. */ void channel_tls_handle_var_cell(var_cell_t *var_cell, or_connection_t *conn) { channel_tls_t *chan; #ifdef KEEP_TIMING_STATS /* how many of each cell have we seen so far this second? needs better * name. */ static int num_versions = 0, num_certs = 0; static time_t current_second = 0; /* from previous calls to time */ time_t now = time(NULL); if (current_second == 0) current_second = now; if (now > current_second) { /* the second has rolled over */ /* print stats */ log_info(LD_OR, "At end of second: %d versions (%d ms), %d certs (%d ms)", num_versions, versions_time / ((now - current_second) * 1000), num_certs, certs_time / ((now - current_second) * 1000)); num_versions = num_certs = 0; versions_time = certs_time = 0; /* remember which second it is, for next time */ current_second = now; } #endif tor_assert(var_cell); tor_assert(conn); chan = conn->chan; if (!chan) { log_warn(LD_CHANNEL, "Got a var_cell_t on an OR connection with no channel"); return; } if (TO_CONN(conn)->marked_for_close) return; switch (TO_CONN(conn)->state) { case OR_CONN_STATE_OR_HANDSHAKING_V2: if (var_cell->command != CELL_VERSIONS) { log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, "Received a cell with command %d in unexpected " "orconn state \"%s\" [%d], channel state \"%s\" [%d]; " "closing the connection.", (int)(var_cell->command), conn_state_to_string(CONN_TYPE_OR, TO_CONN(conn)->state), TO_CONN(conn)->state, channel_state_to_string(TLS_CHAN_TO_BASE(chan)->state), (int)(TLS_CHAN_TO_BASE(chan)->state)); /* * The code in connection_or.c will tell channel_t to close for * error; it will go to CHANNEL_STATE_CLOSING, and then to * CHANNEL_STATE_ERROR when conn is closed. */ connection_or_close_for_error(conn, 0); return; } break; case OR_CONN_STATE_TLS_HANDSHAKING: /* If we're using bufferevents, it's entirely possible for us to * notice "hey, data arrived!" before we notice "hey, the handshake * finished!" And we need to be accepting both at once to handle both * the v2 and v3 handshakes. */ /* fall through */ case OR_CONN_STATE_TLS_SERVER_RENEGOTIATING: if (!(command_allowed_before_handshake(var_cell->command))) { log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, "Received a cell with command %d in unexpected " "orconn state \"%s\" [%d], channel state \"%s\" [%d]; " "closing the connection.", (int)(var_cell->command), conn_state_to_string(CONN_TYPE_OR, TO_CONN(conn)->state), (int)(TO_CONN(conn)->state), channel_state_to_string(TLS_CHAN_TO_BASE(chan)->state), (int)(TLS_CHAN_TO_BASE(chan)->state)); /* see above comment about CHANNEL_STATE_ERROR */ connection_or_close_for_error(conn, 0); return; } else { if (enter_v3_handshake_with_cell(var_cell, chan) < 0) return; } break; case OR_CONN_STATE_OR_HANDSHAKING_V3: if (var_cell->command != CELL_AUTHENTICATE) or_handshake_state_record_var_cell(conn, conn->handshake_state, var_cell, 1); break; /* Everything is allowed */ case OR_CONN_STATE_OPEN: if (conn->link_proto < 3) { log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, "Received a variable-length cell with command %d in orconn " "state %s [%d], channel state %s [%d] with link protocol %d; " "ignoring it.", (int)(var_cell->command), conn_state_to_string(CONN_TYPE_OR, TO_CONN(conn)->state), (int)(TO_CONN(conn)->state), channel_state_to_string(TLS_CHAN_TO_BASE(chan)->state), (int)(TLS_CHAN_TO_BASE(chan)->state), (int)(conn->link_proto)); return; } break; default: log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, "Received var-length cell with command %d in unexpected " "orconn state \"%s\" [%d], channel state \"%s\" [%d]; " "ignoring it.", (int)(var_cell->command), conn_state_to_string(CONN_TYPE_OR, TO_CONN(conn)->state), (int)(TO_CONN(conn)->state), channel_state_to_string(TLS_CHAN_TO_BASE(chan)->state), (int)(TLS_CHAN_TO_BASE(chan)->state)); return; } /* Now handle the cell */ switch (var_cell->command) { case CELL_VERSIONS: ++stats_n_versions_cells_processed; PROCESS_CELL(versions, var_cell, chan); break; case CELL_VPADDING: ++stats_n_vpadding_cells_processed; /* Do nothing */ break; case CELL_CERTS: ++stats_n_certs_cells_processed; PROCESS_CELL(certs, var_cell, chan); break; case CELL_AUTH_CHALLENGE: ++stats_n_auth_challenge_cells_processed; PROCESS_CELL(auth_challenge, var_cell, chan); break; case CELL_AUTHENTICATE: ++stats_n_authenticate_cells_processed; PROCESS_CELL(authenticate, var_cell, chan); break; case CELL_AUTHORIZE: ++stats_n_authorize_cells_processed; /* Ignored so far. */ break; default: log_fn(LOG_INFO, LD_PROTOCOL, "Variable-length cell of unknown type (%d) received.", (int)(var_cell->command)); break; } } /** * 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 command is a cell command that's allowed to start a * V3 handshake. */ static int command_allowed_before_handshake(uint8_t command) { switch (command) { case CELL_VERSIONS: case CELL_VPADDING: case CELL_AUTHORIZE: return 1; default: return 0; } } /** * Start a V3 handshake on an incoming connection * * Called when we as a server receive an appropriate cell while waiting * either for a cell or a TLS handshake. Set the connection's state to * "handshaking_v3', initializes the or_handshake_state field as needed, * and add the cell to the hash of incoming cells.) */ static int enter_v3_handshake_with_cell(var_cell_t *cell, channel_tls_t *chan) { int started_here = 0; tor_assert(cell); tor_assert(chan); tor_assert(chan->conn); started_here = connection_or_nonopen_was_started_here(chan->conn); tor_assert(TO_CONN(chan->conn)->state == OR_CONN_STATE_TLS_HANDSHAKING || TO_CONN(chan->conn)->state == OR_CONN_STATE_TLS_SERVER_RENEGOTIATING); if (started_here) { log_fn(LOG_PROTOCOL_WARN, LD_OR, "Received a cell while TLS-handshaking, not in " "OR_HANDSHAKING_V3, on a connection we originated."); } 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 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 verions cell. */ /*XXXXX symbolic const.*/ chan->base_.wide_circ_ids = chan->conn->link_proto >= MIN_LINK_PROTO_FOR_WIDE_CIRC_IDS; chan->conn->wide_circ_ids = chan->base_.wide_circ_ids; if (send_certs) { if (connection_or_send_certs_cell(chan->conn) < 0) { log_warn(LD_OR, "Couldn't send certs cell"); connection_or_close_for_error(chan->conn, 0); return; } } if (send_chall) { if (connection_or_send_auth_challenge_cell(chan->conn) < 0) { log_warn(LD_OR, "Couldn't send auth_challenge cell"); connection_or_close_for_error(chan->conn, 0); return; } } if (send_netinfo) { if (connection_or_send_netinfo(chan->conn) < 0) { log_warn(LD_OR, "Couldn't send netinfo cell"); connection_or_close_for_error(chan->conn, 0); return; } } } } /** * Process a 'netinfo' cell * * This function is called to handle an incoming NETINFO cell; read and act * on its contents, and set the connection state to "open". */ static void channel_tls_process_netinfo_cell(cell_t *cell, channel_tls_t *chan) { time_t timestamp; uint8_t my_addr_type; uint8_t my_addr_len; const uint8_t *my_addr_ptr; const uint8_t *cp, *end; uint8_t n_other_addrs; time_t now = time(NULL); long apparent_skew = 0; tor_addr_t my_apparent_addr = TOR_ADDR_NULL; tor_assert(cell); tor_assert(chan); tor_assert(chan->conn); if (chan->conn->link_proto < 2) { log_fn(LOG_PROTOCOL_WARN, LD_OR, "Received a NETINFO cell on %s connection; dropping.", chan->conn->link_proto == 0 ? "non-versioned" : "a v1"); return; } if (chan->conn->base_.state != OR_CONN_STATE_OR_HANDSHAKING_V2 && chan->conn->base_.state != OR_CONN_STATE_OR_HANDSHAKING_V3) { log_fn(LOG_PROTOCOL_WARN, LD_OR, "Received a NETINFO cell on non-handshaking connection; dropping."); return; } tor_assert(chan->conn->handshake_state && chan->conn->handshake_state->received_versions); if (chan->conn->base_.state == OR_CONN_STATE_OR_HANDSHAKING_V3) { tor_assert(chan->conn->link_proto >= 3); if (chan->conn->handshake_state->started_here) { if (!(chan->conn->handshake_state->authenticated)) { log_fn(LOG_PROTOCOL_WARN, LD_OR, "Got a NETINFO cell from server, " "but no authentication. Closing the connection."); connection_or_close_for_error(chan->conn, 0); return; } } else { /* we're the server. If the client never authenticated, we have some housekeeping to do.*/ if (!(chan->conn->handshake_state->authenticated)) { tor_assert(tor_digest_is_zero( (const char*)(chan->conn->handshake_state-> authenticated_peer_id))); channel_set_circid_type(TLS_CHAN_TO_BASE(chan), NULL, 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, (const char*)(chan->conn->handshake_state-> authenticated_peer_id), 0); } } } /* Decode the cell. */ timestamp = ntohl(get_uint32(cell->payload)); if (labs(now - chan->conn->handshake_state->sent_versions_at) < 180) { apparent_skew = now - timestamp; } my_addr_type = (uint8_t) cell->payload[4]; my_addr_len = (uint8_t) cell->payload[5]; my_addr_ptr = (uint8_t*) cell->payload + 6; end = cell->payload + CELL_PAYLOAD_SIZE; cp = cell->payload + 6 + my_addr_len; /* 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)); } else if (my_addr_type == RESOLVED_TYPE_IPV6 && my_addr_len == 16) { tor_addr_from_ipv6_bytes(&my_apparent_addr, (const char *) my_addr_ptr); } n_other_addrs = (uint8_t) *cp++; while (n_other_addrs && cp < end-2) { /* Consider all the other addresses; if any matches, this connection is * "canonical." */ tor_addr_t addr; const uint8_t *next = decode_address_from_payload(&addr, cp, (int)(end-cp)); if (next == NULL) { log_fn(LOG_PROTOCOL_WARN, LD_OR, "Bad address in netinfo cell; closing connection."); connection_or_close_for_error(chan->conn, 0); return; } if (tor_addr_eq(&addr, &(chan->conn->real_addr))) { connection_or_set_canonical(chan->conn, 1); break; } cp = next; --n_other_addrs; } /* Act on apparent skew. */ /** Warn when we get a netinfo skew with at least this value. */ #define NETINFO_NOTICE_SKEW 3600 if (labs(apparent_skew) > NETINFO_NOTICE_SKEW && router_get_by_id_digest(chan->conn->identity_digest)) { 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(TLS_CHAN_TO_BASE(chan)->identity_digest, DIGEST_LEN), tor_addr_is_null(&my_apparent_addr) ? "" : fmt_and_decorate_addr(&my_apparent_addr)); } assert_connection_ok(TO_CONN(chan->conn),time(NULL)); } /** * Process a CERTS cell from a channel. * * This function is called to process an incoming CERTS cell on a * channel_tls_t: * * If the other side should not have sent us a CERTS cell, or the cell is * malformed, or it is supposed to authenticate the TLS key but it doesn't, * then mark the connection. * * If the cell has a good cert chain and we're doing a v3 handshake, then * store the certificates in or_handshake_state. If this is the client side * of the connection, we then authenticate the server or mark the connection. * If it's the server side, wait for an AUTHENTICATE cell. */ STATIC void channel_tls_process_certs_cell(var_cell_t *cell, channel_tls_t *chan) { #define MAX_CERT_TYPE_WANTED OR_CERT_TYPE_AUTH_1024 tor_x509_cert_t *certs[MAX_CERT_TYPE_WANTED + 1]; int n_certs, i; certs_cell_t *cc = NULL; int send_netinfo = 0; memset(certs, 0, sizeof(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) 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; tor_x509_cert_t *cert = tor_x509_cert_decode(cert_body, cert_len); if (!cert) { log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, "Received undecodable certificate in CERTS cell from %s:%d", safe_str(chan->conn->base_.address), chan->conn->base_.port); } else { if (certs[cert_type]) { tor_x509_cert_free(cert); ERR("Duplicate x509 certificate"); } else { certs[cert_type] = cert; } } } tor_x509_cert_t *id_cert = certs[OR_CERT_TYPE_ID_1024]; tor_x509_cert_t *auth_cert = certs[OR_CERT_TYPE_AUTH_1024]; tor_x509_cert_t *link_cert = certs[OR_CERT_TYPE_TLS_LINK]; if (chan->conn->handshake_state->started_here) { int severity; if (! (id_cert && link_cert)) ERR("The certs we wanted were missing"); /* Okay. We should be able to check the certificates now. */ if (! tor_tls_cert_matches_key(chan->conn->tls, link_cert)) { ERR("The link certificate didn't match the TLS public key"); } /* Note that this warns more loudly about time and validity if we were * _trying_ to connect to an authority, not necessarily if we _did_ connect * to one. */ if (router_digest_is_trusted_dir( TLS_CHAN_TO_BASE(chan)->identity_digest)) severity = LOG_WARN; else severity = LOG_PROTOCOL_WARN; if (! tor_tls_cert_is_valid(severity, link_cert, id_cert, 0)) ERR("The link certificate was not valid"); if (! tor_tls_cert_is_valid(severity, id_cert, id_cert, 1)) ERR("The ID certificate was not valid"); chan->conn->handshake_state->authenticated = 1; { const common_digests_t *id_digests = tor_x509_cert_get_id_digests(id_cert); crypto_pk_t *identity_rcvd; if (!id_digests) ERR("Couldn't compute digests for key in ID cert"); identity_rcvd = tor_tls_cert_get_key(id_cert); if (!identity_rcvd) ERR("Internal error: Couldn't get RSA key from ID cert."); memcpy(chan->conn->handshake_state->authenticated_peer_id, id_digests->d[DIGEST_SHA1], DIGEST_LEN); channel_set_circid_type(TLS_CHAN_TO_BASE(chan), identity_rcvd, chan->conn->link_proto < MIN_LINK_PROTO_FOR_WIDE_CIRC_IDS); crypto_pk_free(identity_rcvd); } if (connection_or_client_learned_peer_id(chan->conn, chan->conn->handshake_state->authenticated_peer_id) < 0) ERR("Problem setting or checking peer id"); log_info(LD_OR, "Got some good certificates from %s:%d: Authenticated it.", safe_str(chan->conn->base_.address), chan->conn->base_.port); chan->conn->handshake_state->id_cert = id_cert; certs[OR_CERT_TYPE_ID_1024] = NULL; if (!public_server_mode(get_options())) { /* If we initiated the connection and we are not a public server, we * aren't planning to authenticate at all. At this point we know who we * are talking to, so we can just send a netinfo now. */ send_netinfo = 1; } } else { if (! (id_cert && auth_cert)) ERR("The certs we wanted were missing"); /* Remember these certificates so we can check an AUTHENTICATE cell */ if (! tor_tls_cert_is_valid(LOG_PROTOCOL_WARN, auth_cert, id_cert, 1)) ERR("The authentication certificate was not valid"); if (! tor_tls_cert_is_valid(LOG_PROTOCOL_WARN, id_cert, id_cert, 1)) ERR("The ID certificate was not valid"); log_info(LD_OR, "Got some good certificates from %s:%d: " "Waiting for AUTHENTICATE.", safe_str(chan->conn->base_.address), chan->conn->base_.port); /* XXXX check more stuff? */ chan->conn->handshake_state->id_cert = id_cert; chan->conn->handshake_state->auth_cert = auth_cert; certs[OR_CERT_TYPE_ID_1024] = certs[OR_CERT_TYPE_AUTH_1024] = NULL; } chan->conn->handshake_state->received_certs_cell = 1; if (send_netinfo) { if (connection_or_send_netinfo(chan->conn) < 0) { log_warn(LD_OR, "Couldn't send netinfo cell"); connection_or_close_for_error(chan->conn, 0); goto err; } } err: for (unsigned i = 0; i < ARRAY_LENGTH(certs); ++i) { tor_x509_cert_free(certs[i]); } 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 (authtype == AUTHTYPE_RSA_SHA256_TLSSECRET) use_type = authtype; } chan->conn->handshake_state->received_auth_challenge = 1; if (! public_server_mode(get_options())) { /* If we're not a public server then we don't want to authenticate on a connection we originated, and we already sent a NETINFO cell when we got the CERTS cell. We have nothing more to do. */ goto done; } if (use_type >= 0) { log_info(LD_OR, "Got an AUTH_CHALLENGE cell from %s:%d: Sending " "authentication", safe_str(chan->conn->base_.address), chan->conn->base_.port); if (connection_or_send_authenticate_cell(chan->conn, use_type) < 0) { log_warn(LD_OR, "Couldn't send authenticate cell"); connection_or_close_for_error(chan->conn, 0); 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) { uint8_t expected[V3_AUTH_FIXED_PART_LEN+256]; const uint8_t *auth; int authlen; tor_assert(cell); tor_assert(chan); tor_assert(chan->conn); #define ERR(s) \ do { \ log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, \ "Received a bad AUTHENTICATE cell from %s:%d: %s", \ safe_str(chan->conn->base_.address), \ chan->conn->base_.port, (s)); \ connection_or_close_for_error(chan->conn, 0); \ return; \ } while (0) if (chan->conn->base_.state != OR_CONN_STATE_OR_HANDSHAKING_V3) ERR("We're not doing a v3 handshake"); if (chan->conn->link_proto < 3) ERR("We're not using link protocol >= 3"); if (chan->conn->handshake_state->started_here) ERR("We originated this connection"); if (chan->conn->handshake_state->received_authenticate) ERR("We already got one!"); if (chan->conn->handshake_state->authenticated) { /* Should be impossible given other checks */ ERR("The peer is already authenticated"); } if (!(chan->conn->handshake_state->received_certs_cell)) ERR("We never got a certs cell"); if (chan->conn->handshake_state->auth_cert == NULL) ERR("We never got an authentication certificate"); if (chan->conn->handshake_state->id_cert == NULL) ERR("We never got an identity certificate"); if (cell->payload_len < 4) ERR("Cell was way too short"); auth = cell->payload; { uint16_t type = ntohs(get_uint16(auth)); uint16_t len = ntohs(get_uint16(auth+2)); if (4 + len > cell->payload_len) ERR("Authenticator was truncated"); if (type != AUTHTYPE_RSA_SHA256_TLSSECRET) ERR("Authenticator type was not recognized"); auth += 4; authlen = len; } if (authlen < V3_AUTH_BODY_LEN + 1) ERR("Authenticator was too short"); ssize_t bodylen = connection_or_compute_authenticate_cell_body( chan->conn, expected, sizeof(expected), NULL, 1); if (bodylen < 0 || bodylen != V3_AUTH_FIXED_PART_LEN) ERR("Couldn't compute expected AUTHENTICATE cell body"); if (tor_memneq(expected, auth, bodylen)) ERR("Some field in the AUTHENTICATE cell body was not as expected"); { crypto_pk_t *pk = tor_tls_cert_get_key( chan->conn->handshake_state->auth_cert); char d[DIGEST256_LEN]; char *signed_data; size_t keysize; int signed_len; if (!pk) ERR("Internal error: couldn't get RSA key from AUTH cert."); crypto_digest256(d, (char*)auth, V3_AUTH_BODY_LEN, DIGEST_SHA256); keysize = crypto_pk_keysize(pk); signed_data = tor_malloc(keysize); signed_len = crypto_pk_public_checksig(pk, signed_data, keysize, (char*)auth + V3_AUTH_BODY_LEN, authlen - V3_AUTH_BODY_LEN); crypto_pk_free(pk); if (signed_len < 0) { tor_free(signed_data); ERR("Signature wasn't valid"); } if (signed_len < DIGEST256_LEN) { tor_free(signed_data); ERR("Not enough data was signed"); } /* Note that we deliberately allow *more* than DIGEST256_LEN bytes here, * in case they're later used to hold a SHA3 digest or something. */ if (tor_memneq(signed_data, d, DIGEST256_LEN)) { tor_free(signed_data); ERR("Signature did not match data to be signed."); } tor_free(signed_data); } /* Okay, we are authenticated. */ chan->conn->handshake_state->received_authenticate = 1; chan->conn->handshake_state->authenticated = 1; chan->conn->handshake_state->digest_received_data = 0; { crypto_pk_t *identity_rcvd = tor_tls_cert_get_key(chan->conn->handshake_state->id_cert); const common_digests_t *id_digests = tor_x509_cert_get_id_digests(chan->conn->handshake_state->id_cert); /* This must exist; we checked key type when reading the cert. */ tor_assert(id_digests); memcpy(chan->conn->handshake_state->authenticated_peer_id, id_digests->d[DIGEST_SHA1], DIGEST_LEN); channel_set_circid_type(TLS_CHAN_TO_BASE(chan), identity_rcvd, chan->conn->link_proto < MIN_LINK_PROTO_FOR_WIDE_CIRC_IDS); crypto_pk_free(identity_rcvd); connection_or_init_conn_from_address(chan->conn, &(chan->conn->base_.addr), chan->conn->base_.port, (const char*)(chan->conn->handshake_state-> authenticated_peer_id), 0); log_info(LD_OR, "Got an AUTHENTICATE cell from %s:%d: Looks good.", safe_str(chan->conn->base_.address), chan->conn->base_.port); } #undef ERR }