commit c230ff4ca97ae6bf8ddbf2d19a1a7d33371cde3a Author: Nick Mathewson <nickm@torproject.org> Date: Thu Mar 27 22:24:48 2014 -0400 Look at all of a RESOLVED cell; not just the first answer. Also, stop accepting the old kind of RESOLVED cells with no TTL fields; they haven't been sent since 0.1.1.6-alpha. This patch won't work without the fix to #10468 -- it will break DNSPorts unless they set the proper ipv4/6 flags on entry_connection_t. --- src/or/connection_edge.c | 7 +- src/or/connection_edge.h | 4 + src/or/relay.c | 269 ++++++++++++++++++++++++++++++++++++++-------- src/or/relay.h | 13 +++ 4 files changed, 241 insertions(+), 52 deletions(-) diff --git a/src/or/connection_edge.c b/src/or/connection_edge.c index 630c3b9..1ecc553 100644 --- a/src/or/connection_edge.c +++ b/src/or/connection_edge.c @@ -62,11 +62,6 @@ static int connection_ap_process_natd(entry_connection_t *conn); static int connection_exit_connect_dir(edge_connection_t *exitconn); static int consider_plaintext_ports(entry_connection_t *conn, uint16_t port); static int connection_ap_supports_optimistic_data(const entry_connection_t *); -static void connection_ap_handshake_socks_resolved_addr( - entry_connection_t *conn, - const tor_addr_t *answer, - int ttl, - time_t expires); /** An AP stream has failed/finished. If it hasn't already sent back * a socks reply, send one now (based on endreason). Also set @@ -2065,7 +2060,7 @@ tell_controller_about_resolved_result(entry_connection_t *conn, * As connection_ap_handshake_socks_resolved, but take a tor_addr_t to send * as the answer. */ -static void +void connection_ap_handshake_socks_resolved_addr(entry_connection_t *conn, const tor_addr_t *answer, int ttl, diff --git a/src/or/connection_edge.h b/src/or/connection_edge.h index e3a95ad..cbca31a 100644 --- a/src/or/connection_edge.h +++ b/src/or/connection_edge.h @@ -50,6 +50,10 @@ void connection_ap_handshake_socks_resolved(entry_connection_t *conn, const uint8_t *answer, int ttl, time_t expires); +void connection_ap_handshake_socks_resolved_addr(entry_connection_t *conn, + const tor_addr_t *answer, + int ttl, + time_t expires); int connection_exit_begin_conn(cell_t *cell, circuit_t *circ); int connection_exit_begin_resolve(cell_t *cell, or_circuit_t *circ); diff --git a/src/or/relay.c b/src/or/relay.c index 3e28077..ed24397 100644 --- a/src/or/relay.c +++ b/src/or/relay.c @@ -1009,74 +1009,252 @@ connected_cell_parse(const relay_header_t *rh, const cell_t *cell, return 0; } -/** DOCDOC */ -static void +/** Drop all storage held by <b>addr</b>. */ +STATIC void +address_ttl_free(address_ttl_t *addr) +{ + if (!addr) + return; + tor_free(addr->hostname); + tor_free(addr); +} + +/** Parse a resolved cell in <b>cell</b>, with parsed header in <b>rh</b>. + * Return -1 on parse error. On success, add one or more newly allocated + * address_ttl_t to <b>addresses_out</b>; set *<b>errcode_out</b> to + * one of 0, RESOLVED_TYPE_ERROR, or RESOLVED_TYPE_ERROR_TRANSIENT, and + * return 0. */ +STATIC int +resolved_cell_parse(const cell_t *cell, const relay_header_t *rh, + smartlist_t *addresses_out, int *errcode_out) +{ + const uint8_t *cp; + uint8_t answer_type; + size_t answer_len; + address_ttl_t *addr; + size_t remaining; + int errcode = 0; + smartlist_t *addrs; + + tor_assert(cell); + tor_assert(rh); + tor_assert(addresses_out); + tor_assert(errcode_out); + + *errcode_out = 0; + + if (rh->length > RELAY_PAYLOAD_SIZE) + return -1; + + addrs = smartlist_new(); + + cp = cell->payload + RELAY_HEADER_SIZE; + + remaining = rh->length; + while (remaining) { + const uint8_t *cp_orig = cp; + if (remaining < 2) + goto err; + answer_type = *cp++; + answer_len = *cp++; + if (remaining < 2 + answer_len + 4) { + goto err; + } + if (answer_type == RESOLVED_TYPE_IPV4) { + if (answer_len != 4) { + goto err; + } + addr = tor_malloc_zero(sizeof(*addr)); + tor_addr_from_ipv4n(&addr->addr, get_uint32(cp)); + cp += 4; + addr->ttl = ntohl(get_uint32(cp)); + cp += 4; + smartlist_add(addrs, addr); + } else if (answer_type == RESOLVED_TYPE_IPV6) { + if (answer_len != 16) + goto err; + addr = tor_malloc_zero(sizeof(*addr)); + tor_addr_from_ipv6_bytes(&addr->addr, (const char*) cp); + cp += 16; + addr->ttl = ntohl(get_uint32(cp)); + cp += 4; + smartlist_add(addrs, addr); + } else if (answer_type == RESOLVED_TYPE_HOSTNAME) { + if (answer_len == 0) { + goto err; + } + addr = tor_malloc_zero(sizeof(*addr)); + addr->hostname = tor_memdup_nulterm(cp, answer_len); + cp += answer_len; + addr->ttl = ntohl(get_uint32(cp)); + cp += 4; + smartlist_add(addrs, addr); + } else if (answer_type == RESOLVED_TYPE_ERROR_TRANSIENT || + answer_type == RESOLVED_TYPE_ERROR) { + errcode = answer_type; + /* Ignore the error contents */ + cp += answer_len + 4; + } else { + cp += answer_len + 4; + } + tor_assert(((ssize_t)remaining) >= (cp - cp_orig)); + remaining -= (cp - cp_orig); + } + + if (errcode && smartlist_len(addrs) == 0) { + /* Report an error only if there were no results. */ + *errcode_out = errcode; + } + + smartlist_add_all(addresses_out, addrs); + smartlist_free(addrs); + + return 0; + + err: + /* On parse error, don't report any results */ + SMARTLIST_FOREACH(addrs, address_ttl_t *, a, address_ttl_free(a)); + smartlist_free(addrs); + return -1; +} + +/** Helper for connection_edge_process_resolved_cell: given an error code, + * an entry_connection, and a list of address_ttl_t *, report the best answer + * to the entry_connection. */ +STATIC void +connection_ap_handshake_socks_got_resolve_cell(entry_connection_t *conn, + int error_code, + smartlist_t *results) +{ + address_ttl_t *addr_ipv4 = NULL; + address_ttl_t *addr_ipv6 = NULL; + address_ttl_t *addr_hostname = NULL; + address_ttl_t *addr_best = NULL; + + /* If it's an error code, that's easy. */ + if (error_code) { + tor_assert(error_code == RESOLVED_TYPE_ERROR || + error_code == RESOLVED_TYPE_ERROR_TRANSIENT); + connection_ap_handshake_socks_resolved(conn, + error_code,0,NULL,-1,-1); + return; + } + + /* Get the first answer of each type. */ + SMARTLIST_FOREACH_BEGIN(results, address_ttl_t *, addr) { + if (addr->hostname) { + if (!addr_hostname) { + addr_hostname = addr; + } + } else if (tor_addr_family(&addr->addr) == AF_INET) { + if (!addr_ipv4 && conn->ipv4_traffic_ok) { + addr_ipv4 = addr; + } + } else if (tor_addr_family(&addr->addr) == AF_INET6) { + if (!addr_ipv6 && conn->ipv6_traffic_ok) { + addr_ipv6 = addr; + } + } + } SMARTLIST_FOREACH_END(addr); + + /* Now figure out which type we wanted to deliver. */ + if (conn->socks_request->command == SOCKS_COMMAND_RESOLVE_PTR) { + if (addr_hostname) { + connection_ap_handshake_socks_resolved(conn, + RESOLVED_TYPE_HOSTNAME, + strlen(addr_hostname->hostname), + (uint8_t*)addr_hostname->hostname, + addr_hostname->ttl,-1); + } else { + connection_ap_handshake_socks_resolved(conn, + RESOLVED_TYPE_ERROR,0,NULL,-1,-1); + } + return; + } + + if (conn->prefer_ipv6_traffic) { + addr_best = addr_ipv6 ? addr_ipv6 : addr_ipv4; + } else { + addr_best = addr_ipv4 ? addr_ipv4 : addr_ipv6; + } + + /* Now convert it to the ugly old interface */ + if (! addr_best) { + connection_ap_handshake_socks_resolved(conn, + RESOLVED_TYPE_ERROR,0,NULL,-1,-1); + return; + } + + connection_ap_handshake_socks_resolved_addr(conn, + &addr_best->addr, + addr_best->ttl, + -1); + + remap_event_helper(conn, &addr_best->addr); +} + +/** Handle a RELAY_COMMAND_RESOLVED cell that we received on a non-open AP + * stream. */ +static int connection_edge_process_resolved_cell(edge_connection_t *conn, const cell_t *cell, const relay_header_t *rh) { - int ttl; - int answer_len; - uint8_t answer_type; entry_connection_t *entry_conn = EDGE_TO_ENTRY_CONN(conn); + smartlist_t *resolved_addresses = NULL; + int errcode = 0; + if (conn->base_.state != AP_CONN_STATE_RESOLVE_WAIT) { log_fn(LOG_PROTOCOL_WARN, LD_APP, "Got a 'resolved' cell while " "not in state resolve_wait. Dropping."); - return; + return 0; } tor_assert(SOCKS_COMMAND_IS_RESOLVE(entry_conn->socks_request->command)); - answer_len = cell->payload[RELAY_HEADER_SIZE+1]; - if (rh->length < 2 || answer_len+2>rh->length) { + + resolved_addresses = smartlist_new(); + if (resolved_cell_parse(cell, rh, resolved_addresses, &errcode)) { log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, "Dropping malformed 'resolved' cell"); connection_mark_unattached_ap(entry_conn, END_STREAM_REASON_TORPROTOCOL); - return; - } - - answer_type = cell->payload[RELAY_HEADER_SIZE]; - if (rh->length >= answer_len+6) - ttl = (int)ntohl(get_uint32(cell->payload+RELAY_HEADER_SIZE+ - 2+answer_len)); - else - ttl = -1; - if (answer_type == RESOLVED_TYPE_IPV4 || - answer_type == RESOLVED_TYPE_IPV6) { - tor_addr_t addr; - if (decode_address_from_payload(&addr, cell->payload+RELAY_HEADER_SIZE, - rh->length) && - tor_addr_is_internal(&addr, 0) && - get_options()->ClientDNSRejectInternalAddresses) { - log_info(LD_APP,"Got a resolve with answer %s. Rejecting.", - fmt_addr(&addr)); + goto done; + } + + if (get_options()->ClientDNSRejectInternalAddresses) { + int orig_len = smartlist_len(resolved_addresses); + SMARTLIST_FOREACH_BEGIN(resolved_addresses, address_ttl_t *, addr) { + if (addr->hostname == NULL && tor_addr_is_internal(&addr->addr, 0)) { + log_info(LD_APP, "Got a resolved cell with answer %s; dropping that " + "answer.", + safe_str_client(fmt_addr(&addr->addr))); + address_ttl_free(addr); + SMARTLIST_DEL_CURRENT(resolved_addresses, addr); + } + } SMARTLIST_FOREACH_END(addr); + if (orig_len && smartlist_len(resolved_addresses) == 0) { + log_info(LD_APP, "Got a resolved cell with only private addresses; " + "dropping it."); connection_ap_handshake_socks_resolved(entry_conn, RESOLVED_TYPE_ERROR_TRANSIENT, 0, NULL, 0, TIME_MAX); connection_mark_unattached_ap(entry_conn, END_STREAM_REASON_TORPROTOCOL); - return; + goto done; } } - connection_ap_handshake_socks_resolved(entry_conn, - answer_type, - cell->payload[RELAY_HEADER_SIZE+1], /*answer_len*/ - cell->payload+RELAY_HEADER_SIZE+2, /*answer*/ - ttl, - -1); - if (answer_type == RESOLVED_TYPE_IPV4 && answer_len == 4) { - tor_addr_t addr; - tor_addr_from_ipv4n(&addr, - get_uint32(cell->payload+RELAY_HEADER_SIZE+2)); - remap_event_helper(entry_conn, &addr); - } else if (answer_type == RESOLVED_TYPE_IPV6 && answer_len == 16) { - tor_addr_t addr; - tor_addr_from_ipv6_bytes(&addr, - (char*)(cell->payload+RELAY_HEADER_SIZE+2)); - remap_event_helper(entry_conn, &addr); - } + + connection_ap_handshake_socks_got_resolve_cell(entry_conn, + errcode, + resolved_addresses); + connection_mark_unattached_ap(entry_conn, END_STREAM_REASON_DONE | END_STREAM_REASON_FLAG_ALREADY_SOCKS_REPLIED); + done: + SMARTLIST_FOREACH(resolved_addresses, address_ttl_t *, addr, + address_ttl_free(addr)); + smartlist_free(resolved_addresses); + return 0; } /** An incoming relay cell has arrived from circuit <b>circ</b> to @@ -1203,8 +1381,7 @@ connection_edge_process_relay_cell_not_open( } if (conn->base_.type == CONN_TYPE_AP && rh->command == RELAY_COMMAND_RESOLVED) { - connection_edge_process_resolved_cell(conn, cell, rh); - return 0; + return connection_edge_process_resolved_cell(conn, cell, rh); } log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, diff --git a/src/or/relay.h b/src/or/relay.h index 4e1c7f5..bd5c908 100644 --- a/src/or/relay.h +++ b/src/or/relay.h @@ -83,6 +83,19 @@ int relay_crypt(circuit_t *circ, cell_t *cell, cell_direction_t cell_direction, #ifdef RELAY_PRIVATE STATIC int connected_cell_parse(const relay_header_t *rh, const cell_t *cell, tor_addr_t *addr_out, int *ttl_out); +/** An address-and-ttl tuple as yielded by resolved_cell_parse */ +typedef struct address_ttl_s { + tor_addr_t addr; + char *hostname; + int ttl; +} address_ttl_t; +STATIC void address_ttl_free(address_ttl_t *addr); +STATIC int resolved_cell_parse(const cell_t *cell, const relay_header_t *rh, + smartlist_t *addresses_out, int *errcode_out); +STATIC void connection_ap_handshake_socks_got_resolve_cell( + entry_connection_t *conn, + int error_code, + smartlist_t *results); STATIC packed_cell_t *packed_cell_new(void); STATIC packed_cell_t *cell_queue_pop(cell_queue_t *queue); STATIC size_t cell_queues_get_total_allocation(void);