diff options
Diffstat (limited to 'src/core/or/connection_edge.c')
| -rw-r--r-- | src/core/or/connection_edge.c | 31 |
1 files changed, 25 insertions, 6 deletions
diff --git a/src/core/or/connection_edge.c b/src/core/or/connection_edge.c index 37e83ba71e..26595003c1 100644 --- a/src/core/or/connection_edge.c +++ b/src/core/or/connection_edge.c @@ -432,6 +432,21 @@ warn_if_hs_unreachable(const edge_connection_t *conn, uint8_t reason) } } +/** Given a TTL (in seconds) from a DNS response or from a relay, determine + * what TTL clients and relays should actually use for caching it. */ +uint32_t +clip_dns_ttl(uint32_t ttl) +{ + /* This logic is a defense against "DefectTor" DNS-based traffic + * confirmation attacks, as in https://nymity.ch/tor-dns/tor-dns.pdf . + * We only give two values: a "low" value and a "high" value. + */ + if (ttl < MIN_DNS_TTL) + return MIN_DNS_TTL; + else + return MAX_DNS_TTL; +} + /** Send a relay end cell from stream <b>conn</b> down conn's circuit, and * remember that we've done so. If this is not a client connection, set the * relay end cell's reason for closing as <b>reason</b>. @@ -480,7 +495,7 @@ connection_edge_end(edge_connection_t *conn, uint8_t reason) memcpy(payload+1, tor_addr_to_in6_addr8(&conn->base_.addr), 16); addrlen = 16; } - set_uint32(payload+1+addrlen, htonl(dns_clip_ttl(conn->address_ttl))); + set_uint32(payload+1+addrlen, htonl(clip_dns_ttl(conn->address_ttl))); payload_len += 4+addrlen; } @@ -845,7 +860,7 @@ connected_cell_format_payload(uint8_t *payload_out, return -1; } - set_uint32(payload_out + connected_payload_len, htonl(dns_clip_ttl(ttl))); + set_uint32(payload_out + connected_payload_len, htonl(clip_dns_ttl(ttl))); connected_payload_len += 4; tor_assert(connected_payload_len <= MAX_CONNECTED_CELL_PAYLOAD_LEN); @@ -1648,6 +1663,9 @@ parse_extended_hostname(char *address, hostname_type_t *type_out) log_warn(LD_APP, "Invalid %shostname %s; rejecting", is_onion ? "onion " : "", safe_str_client(address)); + if (*type_out == ONION_V3_HOSTNAME) { + *type_out = BAD_HOSTNAME; + } return false; } @@ -2124,7 +2142,7 @@ connection_ap_handshake_rewrite_and_attach(entry_connection_t *conn, if (!parse_extended_hostname(socks->address, &addresstype)) { control_event_client_status(LOG_WARN, "SOCKS_BAD_HOSTNAME HOSTNAME=%s", escaped(socks->address)); - if (addresstype == ONION_V3_HOSTNAME) { + if (addresstype == BAD_HOSTNAME) { conn->socks_request->socks_extended_error_code = SOCKS5_HS_BAD_ADDRESS; } connection_mark_unattached_ap(conn, END_STREAM_REASON_TORPROTOCOL); @@ -3444,8 +3462,9 @@ tell_controller_about_resolved_result(entry_connection_t *conn, expires = time(NULL) + ttl; if (answer_type == RESOLVED_TYPE_IPV4 && answer_len >= 4) { char *cp = tor_dup_ip(ntohl(get_uint32(answer))); - control_event_address_mapped(conn->socks_request->address, - cp, expires, NULL, 0); + if (cp) + control_event_address_mapped(conn->socks_request->address, + cp, expires, NULL, 0); tor_free(cp); } else if (answer_type == RESOLVED_TYPE_HOSTNAME && answer_len < 256) { char *cp = tor_strndup(answer, answer_len); @@ -3518,7 +3537,7 @@ connection_ap_handshake_socks_resolved,(entry_connection_t *conn, } } else if (answer_type == RESOLVED_TYPE_IPV6 && answer_len == 16) { tor_addr_t a; - tor_addr_from_ipv6_bytes(&a, (char*)answer); + tor_addr_from_ipv6_bytes(&a, answer); if (! tor_addr_is_null(&a)) { client_dns_set_addressmap(conn, conn->socks_request->address, &a, |