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author | Roger Dingledine <arma@torproject.org> | 2003-12-16 22:56:50 +0000 |
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committer | Roger Dingledine <arma@torproject.org> | 2003-12-16 22:56:50 +0000 |
commit | 21cc01299bfb694790c0602fc9edc16ce9f147a1 (patch) | |
tree | ba612c1efad43c4cfb2e1bce158dc3e07acb8b78 /src | |
parent | d3a20675849e689fa50bf5afb1dc2c2aa43392f0 (diff) | |
download | tor-21cc01299bfb694790c0602fc9edc16ce9f147a1.tar tor-21cc01299bfb694790c0602fc9edc16ce9f147a1.tar.gz |
infrastructure for integrity-checks in relay cells
make circuit_consider_sending_sendme use connection_edge_send_command
fix endian bug in relay length handling (maybe)
svn:r946
Diffstat (limited to 'src')
-rw-r--r-- | src/or/circuit.c | 80 | ||||
-rw-r--r-- | src/or/connection.c | 2 | ||||
-rw-r--r-- | src/or/connection_edge.c | 29 | ||||
-rw-r--r-- | src/or/or.h | 16 |
4 files changed, 73 insertions, 54 deletions
diff --git a/src/or/circuit.c b/src/or/circuit.c index 2709445b8..a4d39cb3a 100644 --- a/src/or/circuit.c +++ b/src/or/circuit.c @@ -194,7 +194,7 @@ circuit_t *circuit_get_by_conn(connection_t *conn) { } /* Find the newest circ that conn can use, preferably one which is - * dirty and not too old. + * dirty. Circ must not be too old. * If !conn, return newest. * * If must_be_open, ignore circs not in CIRCUIT_STATE_OPEN. @@ -303,6 +303,35 @@ int circuit_stream_is_being_handled(connection_t *conn) { return 0; } +/* update digest from the payload of cell. assign integrity part to cell. */ +void relay_set_digest(crypto_digest_env_t *digest, cell_t *cell) { + uint32_t integrity; + + crypto_digest_add_bytes(digest, cell->payload, CELL_PAYLOAD_SIZE); + crypto_digest_get_digest(digest, (char *)&integrity, 4); + SET_CELL_RELAY_INTEGRITY(*cell, integrity); +} + +/* update digest from the payload of cell (with the integrity part set + * to 0). If the integrity part is valid return 0, else return -1. + */ +int relay_check_digest(crypto_digest_env_t *digest, cell_t *cell) { + uint32_t received_integrity, calculated_integrity; + + received_integrity = CELL_RELAY_INTEGRITY(*cell); + SET_CELL_RELAY_INTEGRITY(*cell, 0); + + crypto_digest_add_bytes(digest, cell->payload, CELL_PAYLOAD_SIZE); + crypto_digest_get_digest(digest, (char *)&calculated_integrity, 4); + + if(received_integrity != calculated_integrity) { + log_fn(LOG_WARN,"Integrity check on cell payload failed. Bug or attack. (%d vs %d).", + received_integrity, calculated_integrity); + return -1; + } + return 0; +} + int circuit_deliver_relay_cell(cell_t *cell, circuit_t *circ, int cell_direction, crypt_path_t *layer_hint) { connection_t *conn=NULL; @@ -321,12 +350,10 @@ int circuit_deliver_relay_cell(cell_t *cell, circuit_t *circ, if(recognized) { if(cell_direction == CELL_DIRECTION_OUT) { -#if 0 - if(relay_update_digest(circ->n_digest, cell) < 0) { + if(relay_check_digest(circ->n_digest, cell) < 0) { log_fn(LOG_WARN,"outgoing cell failed integrity check. Closing circ."); return -1; } -#endif ++stats_n_relay_cells_delivered; log_fn(LOG_DEBUG,"Sending to exit."); if (connection_edge_process_relay_cell(cell, circ, conn, EDGE_EXIT, NULL) < 0) { @@ -335,12 +362,10 @@ int circuit_deliver_relay_cell(cell_t *cell, circuit_t *circ, } } if(cell_direction == CELL_DIRECTION_IN) { -#if 0 - if(relay_update_digest(layer_hint->p_digest, cell) < 0) { + if(relay_check_digest(layer_hint->b_digest, cell) < 0) { log_fn(LOG_WARN,"outgoing cell failed integrity check. Closing circ."); return -1; } -#endif ++stats_n_relay_cells_delivered; log_fn(LOG_DEBUG,"Sending to AP."); if (connection_edge_process_relay_cell(cell, circ, conn, EDGE_AP, layer_hint) < 0) { @@ -545,39 +570,20 @@ int circuit_consider_stop_edge_reading(circuit_t *circ, int edge_type, crypt_pat return 1; } -int circuit_consider_sending_sendme(circuit_t *circ, int edge_type, crypt_path_t *layer_hint) { - cell_t cell; - - assert(circ); - - memset(&cell, 0, sizeof(cell_t)); - cell.command = CELL_RELAY; - SET_CELL_RELAY_COMMAND(cell, RELAY_COMMAND_SENDME); - SET_CELL_STREAM_ID(cell, ZERO_STREAM); - SET_CELL_RELAY_LENGTH(cell, 0); - - if(edge_type == EDGE_AP) { /* i'm the AP */ - cell.circ_id = circ->n_circ_id; - while(layer_hint->deliver_window < CIRCWINDOW_START-CIRCWINDOW_INCREMENT) { - log_fn(LOG_DEBUG,"deliver_window %d, Queueing sendme forward.", layer_hint->deliver_window); +void circuit_consider_sending_sendme(circuit_t *circ, int edge_type, crypt_path_t *layer_hint) { + while((edge_type == EDGE_AP ? layer_hint->deliver_window : circ->deliver_window) < + CIRCWINDOW_START - CIRCWINDOW_INCREMENT) { + log_fn(LOG_DEBUG,"Queueing circuit sendme."); + if(edge_type == EDGE_AP) layer_hint->deliver_window += CIRCWINDOW_INCREMENT; - if(circuit_deliver_relay_cell(&cell, circ, CELL_DIRECTION_OUT, layer_hint) < 0) { - log_fn(LOG_WARN,"At AP: circuit_deliver_relay_cell failed."); - return -1; - } - } - } else if(edge_type == EDGE_EXIT) { /* i'm the exit */ - cell.circ_id = circ->p_circ_id; - while(circ->deliver_window < CIRCWINDOW_START-CIRCWINDOW_INCREMENT) { - log_fn(LOG_DEBUG,"deliver_window %d, Queueing sendme back.", circ->deliver_window); + else circ->deliver_window += CIRCWINDOW_INCREMENT; - if(circuit_deliver_relay_cell(&cell, circ, CELL_DIRECTION_IN, layer_hint) < 0) { - log_fn(LOG_WARN,"At exit: circuit_deliver_relay_cell failed."); - return -1; - } + if(connection_edge_send_command(NULL, circ, RELAY_COMMAND_SENDME, + NULL, 0, layer_hint) < 0) { + log_fn(LOG_WARN,"connection_edge_send_command failed. Returning."); + return; /* the circuit's closed, don't continue */ } } - return 0; } void circuit_close(circuit_t *circ) { @@ -602,6 +608,8 @@ void circuit_close(circuit_t *circ) { if (circ->state == CIRCUIT_STATE_BUILDING || circ->state == CIRCUIT_STATE_OR_WAIT) { /* If we never built the circuit, note it as a failure. */ + /* Note that we can't just check circ->cpath here, because if + * circuit-building failed immediately, it won't be set yet. */ circuit_increment_failure_count(); } circuit_free(circ); diff --git a/src/or/connection.c b/src/or/connection.c index 36a928219..11852a973 100644 --- a/src/or/connection.c +++ b/src/or/connection.c @@ -371,7 +371,7 @@ int connection_read_to_buf(connection_t *conn) { if(connection_speaks_cells(conn)) { at_most = 30*(CELL_NETWORK_SIZE); } else { - at_most = 30*(CELL_PAYLOAD_SIZE - RELAY_HEADER_SIZE); + at_most = 30*(RELAY_PAYLOAD_SIZE); } if(at_most > global_read_bucket) diff --git a/src/or/connection_edge.c b/src/or/connection_edge.c index 4d6be1106..73c5b373c 100644 --- a/src/or/connection_edge.c +++ b/src/or/connection_edge.c @@ -132,18 +132,18 @@ int connection_edge_send_command(connection_t *fromconn, circuit_t *circ, int re if(!circ) { log_fn(LOG_WARN,"no circ. Closing."); - return 0; + return -1; } if(!fromconn || relay_command == RELAY_COMMAND_BEGIN) /* XXX more */ is_control_cell = 1; memset(&cell, 0, sizeof(cell_t)); - if(fromconn && fromconn->type == CONN_TYPE_AP) { +// if(fromconn && fromconn->type == CONN_TYPE_AP) { + if(cpath_layer) { cell.circ_id = circ->n_circ_id; cell_direction = CELL_DIRECTION_OUT; } else { - /* NOTE: if !fromconn, we assume that it's heading towards the OP */ cell.circ_id = circ->p_circ_id; cell_direction = CELL_DIRECTION_IN; } @@ -159,6 +159,12 @@ int connection_edge_send_command(connection_t *fromconn, circuit_t *circ, int re if(payload_len) { memcpy(cell.payload+RELAY_HEADER_SIZE,payload,payload_len); } + + if(cell_direction == CELL_DIRECTION_OUT) /* AP */ + relay_set_digest(cpath_layer->f_digest, &cell); + else /* exit */ + relay_set_digest(circ->p_digest, &cell); + log_fn(LOG_DEBUG,"delivering %d cell %s.", relay_command, cell_direction == CELL_DIRECTION_OUT ? "forward" : "backward"); @@ -231,11 +237,7 @@ int connection_edge_process_relay_cell(cell_t *cell, circuit_t *circ, connection } log_fn(LOG_DEBUG,"circ deliver_window now %d.", edge_type == EDGE_AP ? layer_hint->deliver_window : circ->deliver_window); - if(circuit_consider_sending_sendme(circ, edge_type, layer_hint) < 0) { - log_fn(LOG_WARN,"circuit_consider_sending_sendme() failed."); - conn->has_sent_end = 1; /* we failed because conn is broken. can't send end. */ - return -1; - } + circuit_consider_sending_sendme(circ, edge_type, layer_hint); if(!conn) { log_fn(LOG_INFO,"relay cell dropped, unknown stream %d.",*(int*)conn->stream_id); @@ -247,7 +249,6 @@ int connection_edge_process_relay_cell(cell_t *cell, circuit_t *circ, connection return -1; /* somebody's breaking protocol. kill the whole circuit. */ } -// printf("New text for buf (%d bytes): '%s'", cell->length - RELAY_HEADER_SIZE, cell->payload + RELAY_HEADER_SIZE); stats_n_data_bytes_received += CELL_RELAY_LENGTH(*cell); connection_write_to_buf(cell->payload + RELAY_HEADER_SIZE, CELL_RELAY_LENGTH(*cell), conn); @@ -416,7 +417,7 @@ int connection_edge_finished_flushing(connection_t *conn) { /* deliver a 'connected' relay cell back through the circuit. */ *(uint32_t*)connected_payload = htonl(conn->addr); if(connection_edge_send_command(conn, circuit_get_by_conn(conn), - RELAY_COMMAND_CONNECTED, NULL, 0, conn->cpath_layer) < 0) + RELAY_COMMAND_CONNECTED, NULL, 0, NULL) < 0) return 0; /* circuit is closed, don't continue */ assert(conn->package_window > 0); return connection_edge_process_inbuf(conn); /* in case the server has written anything */ @@ -541,10 +542,10 @@ void connection_ap_attach_pending(void) static void connection_edge_consider_sending_sendme(connection_t *conn) { circuit_t *circ; - + if(connection_outbuf_too_full(conn)) return; - + circ = circuit_get_by_conn(conn); if(!circ) { /* this can legitimately happen if the destroy has already @@ -552,7 +553,7 @@ static void connection_edge_consider_sending_sendme(connection_t *conn) { log_fn(LOG_INFO,"No circuit associated with conn. Skipping."); return; } - + while(conn->deliver_window < STREAMWINDOW_START - STREAMWINDOW_INCREMENT) { log_fn(LOG_DEBUG,"Outbuf %d, Queueing stream sendme.", conn->outbuf_flushlen); conn->deliver_window += STREAMWINDOW_INCREMENT; @@ -828,7 +829,7 @@ void connection_exit_connect(connection_t *conn) { /* also, deliver a 'connected' cell back through the circuit. */ *((uint32_t*) connected_payload) = htonl(conn->addr); connection_edge_send_command(conn, circuit_get_by_conn(conn), RELAY_COMMAND_CONNECTED, - connected_payload, 4, conn->cpath_layer); + connected_payload, 4, NULL); } int connection_ap_can_use_exit(connection_t *conn, routerinfo_t *exit) diff --git a/src/or/or.h b/src/or/or.h index 0b63ccf28..27d50d24a 100644 --- a/src/or/or.h +++ b/src/or/or.h @@ -250,9 +250,17 @@ typedef uint16_t circ_id_t; #define CELL_RELAY_COMMAND_END_REASON(c) (*(uint8_t)((c).payload+1)) +/* integrity is the first 32 bits (in network order) of a sha-1 of all + * cell payloads that are relay cells that have been sent / delivered + * to the hop on the * circuit (the integrity is zeroed while doing + * each calculation) + */ +#define CELL_RELAY_INTEGRITY(c) (ntohl(*(uint32_t*)((c).payload+1+STREAM_ID_SIZE))) +#define SET_CELL_RELAY_INTEGRITY(c,i) (*(uint32_t*)((c).payload+1+STREAM_ID_SIZE) = htonl(i)) + /* relay length is how many bytes are used in the cell payload past relay_header_size */ -#define CELL_RELAY_LENGTH(c) (*(uint16_t*)((c).payload+1+STREAM_ID_SIZE+4)) -#define SET_CELL_RELAY_LENGTH(c,len) (*(uint16_t*)((c).payload+1+STREAM_ID_SIZE+4) = (len)) +#define CELL_RELAY_LENGTH(c) (ntohs(*(uint16_t*)((c).payload+1+STREAM_ID_SIZE+4))) +#define SET_CELL_RELAY_LENGTH(c,len) (*(uint16_t*)((c).payload+1+STREAM_ID_SIZE+4) = htons(len)) #define CELL_PAYLOAD_SIZE 509 #define CELL_NETWORK_SIZE 512 @@ -544,6 +552,8 @@ void circuit_expire_building(void); int circuit_count_building(void); int circuit_stream_is_being_handled(connection_t *conn); +void relay_set_digest(crypto_digest_env_t *digest, cell_t *cell); +int relay_check_digest(crypto_digest_env_t *digest, cell_t *cell); int circuit_deliver_relay_cell(cell_t *cell, circuit_t *circ, int cell_direction, crypt_path_t *layer_hint); int relay_crypt(circuit_t *circ, char *in, int inlen, char cell_direction, @@ -552,7 +562,7 @@ int relay_check_recognized(circuit_t *circ, int cell_direction, char *stream, co void circuit_resume_edge_reading(circuit_t *circ, int edge_type, crypt_path_t *layer_hint); int circuit_consider_stop_edge_reading(circuit_t *circ, int edge_type, crypt_path_t *layer_hint); -int circuit_consider_sending_sendme(circuit_t *circ, int edge_type, crypt_path_t *layer_hint); +void circuit_consider_sending_sendme(circuit_t *circ, int edge_type, crypt_path_t *layer_hint); void circuit_close(circuit_t *circ); void circuit_about_to_close_connection(connection_t *conn); |