/* * firewall3 - 3rd OpenWrt UCI firewall implementation * * Copyright (C) 2013-2018 Jo-Philipp Wich * * Permission to use, copy, modify, and/or distribute this software for any * purpose with or without fee is hereby granted, provided that the above * copyright notice and this permission notice appear in all copies. * * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ #include "redirects.h" const struct fw3_option fw3_redirect_opts[] = { FW3_OPT("enabled", bool, redirect, enabled), FW3_OPT("name", string, redirect, name), FW3_OPT("family", family, redirect, family), FW3_OPT("src", device, redirect, src), FW3_OPT("dest", device, redirect, dest), FW3_OPT("ipset", setmatch, redirect, ipset), FW3_OPT("helper", cthelper, redirect, helper), FW3_LIST("proto", protocol, redirect, proto), FW3_OPT("src_ip", network, redirect, ip_src), FW3_LIST("src_mac", mac, redirect, mac_src), FW3_OPT("src_port", port, redirect, port_src), FW3_OPT("src_dip", network, redirect, ip_dest), FW3_OPT("src_dport", port, redirect, port_dest), FW3_OPT("dest_ip", network, redirect, ip_redir), FW3_OPT("dest_port", port, redirect, port_redir), FW3_OPT("extra", string, redirect, extra), FW3_OPT("limit", limit, redirect, limit), FW3_OPT("limit_burst", int, redirect, limit.burst), FW3_OPT("utc_time", bool, redirect, time.utc), FW3_OPT("start_date", date, redirect, time.datestart), FW3_OPT("stop_date", date, redirect, time.datestop), FW3_OPT("start_time", time, redirect, time.timestart), FW3_OPT("stop_time", time, redirect, time.timestop), FW3_OPT("weekdays", weekdays, redirect, time.weekdays), FW3_OPT("monthdays", monthdays, redirect, time.monthdays), FW3_OPT("mark", mark, redirect, mark), FW3_OPT("reflection", bool, redirect, reflection), FW3_OPT("reflection_src", reflection_source, redirect, reflection_src), FW3_OPT("target", target, redirect, target), { } }; static bool check_families(struct uci_element *e, struct fw3_redirect *r) { if (r->family == FW3_FAMILY_ANY) return true; if (r->_src && r->_src->family && r->_src->family != r->family) { warn_elem(e, "refers to source zone with different family"); return false; } if (r->_dest && r->_dest->family && r->_dest->family != r->family) { warn_elem(e, "refers to destination zone with different family"); return false; } if (r->ipset.ptr && r->ipset.ptr->family && r->ipset.ptr->family != r->family) { warn_elem(e, "refers to ipset with different family"); return false; } if (r->helper.ptr && r->helper.ptr->family && r->helper.ptr->family != r->family) { warn_elem(e, "refers to CT helper not supporting family"); return false; } if (r->ip_src.family && r->ip_src.family != r->family) { warn_elem(e, "uses source ip with different family"); return false; } if (r->ip_dest.family && r->ip_dest.family != r->family) { warn_elem(e, "uses destination ip with different family"); return false; } if (r->ip_redir.family && r->ip_redir.family != r->family) { warn_elem(e, "uses redirect ip with different family"); return false; } return true; } static bool compare_addr(struct fw3_address *a, struct fw3_address *b) { if (a->family != FW3_FAMILY_V4 || b->family != FW3_FAMILY_V4) return false; return ((a->address.v4.s_addr & a->mask.v4.s_addr) == (b->address.v4.s_addr & a->mask.v4.s_addr)); } static bool resolve_dest(struct uci_element *e, struct fw3_redirect *redir, struct fw3_state *state) { struct fw3_zone *zone; struct fw3_address *addr; struct list_head *addrs; if (!redir->ip_redir.set) return false; list_for_each_entry(zone, &state->zones, list) { addrs = fw3_resolve_zone_addresses(zone, NULL); if (!addrs) continue; list_for_each_entry(addr, addrs, list) { if (!compare_addr(addr, &redir->ip_redir)) continue; strncpy(redir->dest.name, zone->name, sizeof(redir->dest.name) - 1); redir->dest.set = true; redir->_dest = zone; break; } fw3_free_list(addrs); if (redir->_dest) return true; } return false; } static bool check_local(struct uci_element *e, struct fw3_redirect *redir, struct fw3_state *state) { if (redir->target != FW3_FLAG_DNAT) return false; if (!redir->ip_redir.set) redir->local = true; return redir->local; } static void select_helper(struct fw3_state *state, struct fw3_redirect *redir) { struct fw3_protocol *proto; struct fw3_cthelper *helper; int n_matches = 0; if (!state->defaults.auto_helper) return; if (!redir->_src || redir->target != FW3_FLAG_DNAT) return; if (!redir->port_redir.set || redir->port_redir.invert) return; if (redir->helper.set || redir->helper.ptr) return; if (list_empty(&redir->proto)) return; list_for_each_entry(proto, &redir->proto, list) { helper = fw3_lookup_cthelper_by_proto_port(state, proto, &redir->port_redir); if (helper) n_matches++; } if (n_matches != 1) return; /* store pointer to auto-selected helper but set ".set" flag to false, * to allow later code to decide between configured or auto-selected * helpers */ redir->helper.set = false; redir->helper.ptr = helper; set(redir->_src->flags, FW3_FAMILY_V4, FW3_FLAG_HELPER); } static bool check_redirect(struct fw3_state *state, struct fw3_redirect *redir, struct uci_element *e) { bool valid; if (!redir->enabled) return false; if (redir->src.invert) { warn_section("redirect", redir, e, "must not have an inverted source"); return false; } else if (redir->src.set && !redir->src.any && !(redir->_src = fw3_lookup_zone(state, redir->src.name))) { warn_section("redirect", redir, e, "refers to not existing zone '%s'", redir->src.name); return false; } else if (redir->dest.set && !redir->dest.any && !(redir->_dest = fw3_lookup_zone(state, redir->dest.name))) { warn_section("redirect", redir, e, "refers to not existing zone '%s'", redir->dest.name); return false; } else if (redir->ipset.set && state->disable_ipsets) { warn_section("redirect", redir, e, "skipped due to disabled ipset support"); return false; } else if (redir->ipset.set && !(redir->ipset.ptr = fw3_lookup_ipset(state, redir->ipset.name))) { warn_section("redirect", redir, e, "refers to unknown ipset '%s'", redir->ipset.name); return false; } else if (redir->helper.set && !(redir->helper.ptr = fw3_lookup_cthelper(state, redir->helper.name))) { warn_section("redirect", redir, e, "refers to unknown CT helper '%s'", redir->helper.name); return false; } if (!check_families(e, redir)) return false; if (redir->target == FW3_FLAG_UNSPEC) { warn_section("redirect", redir, e, "has no target specified, defaulting to DNAT"); redir->target = FW3_FLAG_DNAT; } else if (redir->target < FW3_FLAG_DNAT || redir->target > FW3_FLAG_SNAT) { warn_section("redirect", redir, e, "has invalid target specified, defaulting to DNAT"); redir->target = FW3_FLAG_DNAT; } valid = false; if (redir->target == FW3_FLAG_DNAT) { if (redir->src.any) warn_section("redirect", redir, e, "must not have source '*' for DNAT target"); else if (!redir->_src) warn_section("redirect", redir, e, "has no source specified"); else if (redir->helper.invert) warn_section("redirect", redir, e, "must not use a negated helper match"); else { set(redir->_src->flags, FW3_FAMILY_V4, redir->target); valid = true; if (!check_local(e, redir, state) && !redir->dest.set && resolve_dest(e, redir, state)) { warn_section("redirect", redir, e, "does not specify a destination, assuming '%s'", redir->dest.name); } if (redir->reflection && redir->_dest && redir->_src->masq) { set(redir->_dest->flags, FW3_FAMILY_V4, FW3_FLAG_ACCEPT); set(redir->_dest->flags, FW3_FAMILY_V4, FW3_FLAG_DNAT); set(redir->_dest->flags, FW3_FAMILY_V4, FW3_FLAG_SNAT); } if (redir->helper.ptr) set(redir->_src->flags, FW3_FAMILY_V4, FW3_FLAG_HELPER); } } else { if (redir->dest.any) warn_section("redirect", redir, e, "must not have destination '*' for SNAT target"); else if (!redir->_dest) warn_section("redirect", redir, e, "has no destination specified"); else if (!redir->ip_dest.set) warn_section("redirect", redir, e, "has no src_dip option specified"); else if (!list_empty(&redir->mac_src)) warn_section("redirect", redir, e, "must not use 'src_mac' option for SNAT target"); else if (redir->helper.set) warn_section("redirect", redir, e, "must not use 'helper' option for SNAT target"); else { set(redir->_dest->flags, FW3_FAMILY_V4, redir->target); valid = true; } } if (list_empty(&redir->proto)) { warn_section("redirect", redir, e, "does not specify a protocol, assuming TCP+UDP"); fw3_parse_protocol(&redir->proto, "tcpudp", true); } if (!valid) return false; if (redir->target == FW3_FLAG_DNAT && !redir->port_redir.set) redir->port_redir = redir->port_dest; return true; } static struct fw3_redirect * fw3_alloc_redirect(struct fw3_state *state) { struct fw3_redirect *redir; redir = calloc(1, sizeof(*redir)); if (!redir) return NULL; INIT_LIST_HEAD(&redir->proto); INIT_LIST_HEAD(&redir->mac_src); redir->enabled = true; redir->reflection = true; list_add_tail(&redir->list, &state->redirects); return redir; } void fw3_load_redirects(struct fw3_state *state, struct uci_package *p, struct blob_attr *a) { struct uci_section *s; struct uci_element *e; struct fw3_redirect *redir; struct blob_attr *entry; unsigned rem; INIT_LIST_HEAD(&state->redirects); blob_for_each_attr(entry, a, rem) { const char *type; const char *name = "ubus redirect"; if (!fw3_attr_parse_name_type(entry, &name, &type)) continue; if (strcmp(type, "redirect")) continue; redir = fw3_alloc_redirect(state); if (!redir) continue; if (!fw3_parse_blob_options(redir, fw3_redirect_opts, entry, name)) { warn_section("redirect", redir, NULL, "skipped due to invalid options"); fw3_free_redirect(redir); continue; } if (!check_redirect(state, redir, NULL)) { fw3_free_redirect(redir); continue; } select_helper(state, redir); } uci_foreach_element(&p->sections, e) { s = uci_to_section(e); if (strcmp(s->type, "redirect")) continue; redir = fw3_alloc_redirect(state); if (!redir) continue; if (!fw3_parse_options(redir, fw3_redirect_opts, s)) { warn_elem(e, "skipped due to invalid options"); fw3_free_redirect(redir); continue; } if (!check_redirect(state, redir, e)) { fw3_free_redirect(redir); continue; } select_helper(state, redir); } } static void append_chain_nat(struct fw3_ipt_rule *r, struct fw3_redirect *redir) { if (redir->target == FW3_FLAG_DNAT) fw3_ipt_rule_append(r, "zone_%s_prerouting", redir->src.name); else fw3_ipt_rule_append(r, "zone_%s_postrouting", redir->dest.name); } static void set_redirect(struct fw3_ipt_rule *r, struct fw3_port *port) { char buf[sizeof("65535-65535\0")]; fw3_ipt_rule_target(r, "REDIRECT"); if (port && port->set) { if (port->port_min == port->port_max) sprintf(buf, "%u", port->port_min); else snprintf(buf, sizeof(buf), "%u-%u", port->port_min, port->port_max); fw3_ipt_rule_addarg(r, false, "--to-ports", buf); } } static void set_snat_dnat(struct fw3_ipt_rule *r, enum fw3_flag target, struct fw3_address *addr, struct fw3_port *port) { char buf[sizeof("255.255.255.255:65535-65535\0")]; buf[0] = '\0'; if (addr && addr->set) { inet_ntop(AF_INET, &addr->address.v4, buf, sizeof(buf)); } if (port && port->set) { if (port->port_min == port->port_max) sprintf(buf + strlen(buf), ":%u", port->port_min); else sprintf(buf + strlen(buf), ":%u-%u", port->port_min, port->port_max); } if (target == FW3_FLAG_DNAT) { fw3_ipt_rule_target(r, "DNAT"); fw3_ipt_rule_addarg(r, false, "--to-destination", buf); } else { fw3_ipt_rule_target(r, "SNAT"); fw3_ipt_rule_addarg(r, false, "--to-source", buf); } } static void set_target_nat(struct fw3_ipt_rule *r, struct fw3_redirect *redir) { if (redir->local) set_redirect(r, &redir->port_redir); else if (redir->target == FW3_FLAG_DNAT) set_snat_dnat(r, redir->target, &redir->ip_redir, &redir->port_redir); else set_snat_dnat(r, redir->target, &redir->ip_dest, &redir->port_dest); } static void set_comment(struct fw3_ipt_rule *r, const char *name, int num, const char *suffix) { if (name) { if (suffix) fw3_ipt_rule_comment(r, "%s (%s)", name, suffix); else fw3_ipt_rule_comment(r, name); } else { if (suffix) fw3_ipt_rule_comment(r, "@redirect[%u] (%s)", num, suffix); else fw3_ipt_rule_comment(r, "@redirect[%u]", num); } } static void print_redirect(struct fw3_ipt_handle *h, struct fw3_state *state, struct fw3_redirect *redir, int num, struct fw3_protocol *proto, struct fw3_mac *mac) { struct fw3_ipt_rule *r; struct fw3_address *src, *dst; struct fw3_port *spt, *dpt; switch (h->table) { case FW3_TABLE_NAT: src = &redir->ip_src; dst = &redir->ip_dest; spt = &redir->port_src; dpt = &redir->port_dest; if (redir->target == FW3_FLAG_SNAT) { dst = &redir->ip_redir; dpt = &redir->port_redir; } r = fw3_ipt_rule_create(h, proto, NULL, NULL, src, dst); fw3_ipt_rule_sport_dport(r, spt, dpt); fw3_ipt_rule_mac(r, mac); fw3_ipt_rule_ipset(r, &redir->ipset); fw3_ipt_rule_helper(r, &redir->helper); fw3_ipt_rule_limit(r, &redir->limit); fw3_ipt_rule_time(r, &redir->time); fw3_ipt_rule_mark(r, &redir->mark); set_target_nat(r, redir); fw3_ipt_rule_extra(r, redir->extra); set_comment(r, redir->name, num, NULL); append_chain_nat(r, redir); break; case FW3_TABLE_RAW: if (redir->target == FW3_FLAG_DNAT && redir->helper.ptr) { if (!fw3_cthelper_check_proto(redir->helper.ptr, proto)) { info(" ! Skipping protocol %s since helper '%s' does not support it", fw3_protoname(proto), redir->helper.ptr->name); return; } if (!redir->helper.set) info(" - Auto-selected conntrack helper '%s' based on proto/port", redir->helper.ptr->name); r = fw3_ipt_rule_create(h, proto, NULL, NULL, &redir->ip_src, &redir->ip_redir); fw3_ipt_rule_sport_dport(r, &redir->port_src, &redir->port_redir); fw3_ipt_rule_mac(r, mac); fw3_ipt_rule_ipset(r, &redir->ipset); fw3_ipt_rule_limit(r, &redir->limit); fw3_ipt_rule_time(r, &redir->time); fw3_ipt_rule_mark(r, &redir->mark); fw3_ipt_rule_addarg(r, false, "-m", "conntrack"); fw3_ipt_rule_addarg(r, false, "--ctstate", "DNAT"); fw3_ipt_rule_target(r, "CT"); fw3_ipt_rule_addarg(r, false, "--helper", redir->helper.ptr->name); set_comment(r, redir->name, num, "CT helper"); fw3_ipt_rule_append(r, "zone_%s_helper", redir->_src->name); } break; default: break; } } static void print_reflection(struct fw3_ipt_handle *h, struct fw3_state *state, struct fw3_redirect *redir, int num, struct fw3_protocol *proto, struct fw3_address *ra, struct fw3_address *ia, struct fw3_address *ea) { struct fw3_ipt_rule *r; switch (h->table) { case FW3_TABLE_NAT: r = fw3_ipt_rule_create(h, proto, NULL, NULL, ia, ea); fw3_ipt_rule_sport_dport(r, NULL, &redir->port_dest); fw3_ipt_rule_limit(r, &redir->limit); fw3_ipt_rule_time(r, &redir->time); set_comment(r, redir->name, num, "reflection"); set_snat_dnat(r, FW3_FLAG_DNAT, &redir->ip_redir, &redir->port_redir); fw3_ipt_rule_replace(r, "zone_%s_prerouting", redir->dest.name); r = fw3_ipt_rule_create(h, proto, NULL, NULL, ia, &redir->ip_redir); fw3_ipt_rule_sport_dport(r, NULL, &redir->port_redir); fw3_ipt_rule_limit(r, &redir->limit); fw3_ipt_rule_time(r, &redir->time); set_comment(r, redir->name, num, "reflection"); set_snat_dnat(r, FW3_FLAG_SNAT, ra, NULL); fw3_ipt_rule_replace(r, "zone_%s_postrouting", redir->dest.name); break; default: break; } } static void expand_redirect(struct fw3_ipt_handle *handle, struct fw3_state *state, struct fw3_redirect *redir, int num) { struct list_head *ext_addrs, *int_addrs; struct fw3_address *ext_addr, *int_addr, ref_addr; struct fw3_protocol *proto; struct fw3_mac *mac; if (redir->name) info(" * Redirect '%s'", redir->name); else info(" * Redirect #%u", num); if (!fw3_is_family(redir->_src, handle->family) || !fw3_is_family(redir->_dest, handle->family)) { info(" ! Skipping due to different family of zone"); return; } if (!fw3_is_family(&redir->ip_src, handle->family) || !fw3_is_family(&redir->ip_dest, handle->family) || !fw3_is_family(&redir->ip_redir, handle->family)) { if (!redir->ip_src.resolved || !redir->ip_dest.resolved || !redir->ip_redir.resolved) info(" ! Skipping due to different family of ip address"); return; } if (redir->ipset.ptr) { if (!fw3_is_family(redir->ipset.ptr, handle->family)) { info(" ! Skipping due to different family in ipset"); return; } if (!fw3_check_ipset(redir->ipset.ptr)) { info(" ! Skipping due to missing ipset '%s'", redir->ipset.ptr->external ? redir->ipset.ptr->external : redir->ipset.ptr->name); return; } set(redir->ipset.ptr->flags, handle->family, handle->family); } fw3_foreach(proto, &redir->proto) fw3_foreach(mac, &redir->mac_src) print_redirect(handle, state, redir, num, proto, mac); /* reflection rules */ if (redir->target != FW3_FLAG_DNAT || !redir->reflection || redir->local) return; if (!redir->_dest || !redir->_src->masq) return; ext_addrs = fw3_resolve_zone_addresses(redir->_src, &redir->ip_dest); int_addrs = fw3_resolve_zone_addresses(redir->_dest, NULL); if (!ext_addrs || !int_addrs) goto out; list_for_each_entry(ext_addr, ext_addrs, list) { if (!fw3_is_family(ext_addr, handle->family)) continue; list_for_each_entry(int_addr, int_addrs, list) { if (!fw3_is_family(int_addr, handle->family)) continue; fw3_foreach(proto, &redir->proto) { if (!proto) continue; if (redir->reflection_src == FW3_REFLECTION_INTERNAL) ref_addr = *int_addr; else ref_addr = *ext_addr; ref_addr.mask.v4.s_addr = 0xFFFFFFFF; ext_addr->mask.v4.s_addr = 0xFFFFFFFF; print_reflection(handle, state, redir, num, proto, &ref_addr, int_addr, ext_addr); } } } out: fw3_free_list(ext_addrs); fw3_free_list(int_addrs); } void fw3_print_redirects(struct fw3_ipt_handle *handle, struct fw3_state *state) { int num = 0; struct fw3_redirect *redir; if (handle->family == FW3_FAMILY_V6) return; if (handle->table != FW3_TABLE_FILTER && handle->table != FW3_TABLE_NAT && handle->table != FW3_TABLE_RAW) return; list_for_each_entry(redir, &state->redirects, list) { if (handle->table == FW3_TABLE_RAW && !redir->helper.ptr) continue; expand_redirect(handle, state, redir, num++); } }