/* dnsmasq is Copyright (c) 2000-2016 Simon Kelley This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; version 2 dated June, 1991, or (at your option) version 3 dated 29 June, 2007. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see . */ #include "dnsmasq.h" #ifdef HAVE_AUTH static struct addrlist *find_subnet(struct auth_zone *zone, int flag, struct all_addr *addr_u) { struct addrlist *subnet; for (subnet = zone->subnet; subnet; subnet = subnet->next) { if (!(subnet->flags & ADDRLIST_IPV6)) { struct in_addr netmask, addr = addr_u->addr.addr4; if (!(flag & F_IPV4)) continue; netmask.s_addr = htonl(~(in_addr_t)0 << (32 - subnet->prefixlen)); if (is_same_net(addr, subnet->addr.addr.addr4, netmask)) return subnet; } #ifdef HAVE_IPV6 else if (is_same_net6(&(addr_u->addr.addr6), &subnet->addr.addr.addr6, subnet->prefixlen)) return subnet; #endif } return NULL; } static int filter_zone(struct auth_zone *zone, int flag, struct all_addr *addr_u) { /* No zones specified, no filter */ if (!zone->subnet) return 1; return find_subnet(zone, flag, addr_u) != NULL; } int in_zone(struct auth_zone *zone, char *name, char **cut) { size_t namelen = strlen(name); size_t domainlen = strlen(zone->domain); if (cut) *cut = NULL; if (namelen >= domainlen && hostname_isequal(zone->domain, &name[namelen - domainlen])) { if (namelen == domainlen) return 1; if (name[namelen - domainlen - 1] == '.') { if (cut) *cut = &name[namelen - domainlen - 1]; return 1; } } return 0; } size_t answer_auth(struct dns_header *header, char *limit, size_t qlen, time_t now, union mysockaddr *peer_addr, int local_query, int do_bit, int have_pseudoheader) { char *name = daemon->namebuff; unsigned char *p, *ansp; int qtype, qclass; int nameoffset, axfroffset = 0; int q, anscount = 0, authcount = 0; struct crec *crecp; int auth = !local_query, trunc = 0, nxdomain = 1, soa = 0, ns = 0, axfr = 0; struct auth_zone *zone = NULL; struct addrlist *subnet = NULL; char *cut; struct mx_srv_record *rec, *move, **up; struct txt_record *txt; struct interface_name *intr; struct naptr *na; struct all_addr addr; struct cname *a; if (ntohs(header->qdcount) == 0 || OPCODE(header) != QUERY ) return 0; /* determine end of question section (we put answers there) */ if (!(ansp = skip_questions(header, qlen))) return 0; /* bad packet */ /* now process each question, answers go in RRs after the question */ p = (unsigned char *)(header+1); for (q = ntohs(header->qdcount); q != 0; q--) { unsigned short flag = 0; int found = 0; /* save pointer to name for copying into answers */ nameoffset = p - (unsigned char *)header; /* now extract name as .-concatenated string into name */ if (!extract_name(header, qlen, &p, name, 1, 4)) return 0; /* bad packet */ GETSHORT(qtype, p); GETSHORT(qclass, p); if (qclass != C_IN) { auth = 0; continue; } if ((qtype == T_PTR || qtype == T_SOA || qtype == T_NS) && (flag = in_arpa_name_2_addr(name, &addr)) && !local_query) { for (zone = daemon->auth_zones; zone; zone = zone->next) if ((subnet = find_subnet(zone, flag, &addr))) break; if (!zone) { auth = 0; continue; } else if (qtype == T_SOA) soa = 1, found = 1; else if (qtype == T_NS) ns = 1, found = 1; } if (qtype == T_PTR && flag) { intr = NULL; if (flag == F_IPV4) for (intr = daemon->int_names; intr; intr = intr->next) { struct addrlist *addrlist; for (addrlist = intr->addr; addrlist; addrlist = addrlist->next) if (!(addrlist->flags & ADDRLIST_IPV6) && addr.addr.addr4.s_addr == addrlist->addr.addr.addr4.s_addr) break; if (addrlist) break; else while (intr->next && strcmp(intr->intr, intr->next->intr) == 0) intr = intr->next; } #ifdef HAVE_IPV6 else if (flag == F_IPV6) for (intr = daemon->int_names; intr; intr = intr->next) { struct addrlist *addrlist; for (addrlist = intr->addr; addrlist; addrlist = addrlist->next) if ((addrlist->flags & ADDRLIST_IPV6) && IN6_ARE_ADDR_EQUAL(&addr.addr.addr6, &addrlist->addr.addr.addr6)) break; if (addrlist) break; else while (intr->next && strcmp(intr->intr, intr->next->intr) == 0) intr = intr->next; } #endif if (intr) { if (local_query || in_zone(zone, intr->name, NULL)) { found = 1; log_query(flag | F_REVERSE | F_CONFIG, intr->name, &addr, NULL); if (add_resource_record(header, limit, &trunc, nameoffset, &ansp, daemon->auth_ttl, NULL, T_PTR, C_IN, "d", intr->name)) anscount++; } } if ((crecp = cache_find_by_addr(NULL, &addr, now, flag))) do { strcpy(name, cache_get_name(crecp)); if (crecp->flags & F_DHCP && !option_bool(OPT_DHCP_FQDN)) { char *p = strchr(name, '.'); if (p) *p = 0; /* must be bare name */ /* add external domain */ if (zone) { strcat(name, "."); strcat(name, zone->domain); } log_query(flag | F_DHCP | F_REVERSE, name, &addr, record_source(crecp->uid)); found = 1; if (add_resource_record(header, limit, &trunc, nameoffset, &ansp, daemon->auth_ttl, NULL, T_PTR, C_IN, "d", name)) anscount++; } else if (crecp->flags & (F_DHCP | F_HOSTS) && (local_query || in_zone(zone, name, NULL))) { log_query(crecp->flags & ~F_FORWARD, name, &addr, record_source(crecp->uid)); found = 1; if (add_resource_record(header, limit, &trunc, nameoffset, &ansp, daemon->auth_ttl, NULL, T_PTR, C_IN, "d", name)) anscount++; } else continue; } while ((crecp = cache_find_by_addr(crecp, &addr, now, flag))); if (found) nxdomain = 0; else log_query(flag | F_NEG | F_NXDOMAIN | F_REVERSE | (auth ? F_AUTH : 0), NULL, &addr, NULL); continue; } cname_restart: if (found) /* NS and SOA .arpa requests have set found above. */ cut = NULL; else { for (zone = daemon->auth_zones; zone; zone = zone->next) if (in_zone(zone, name, &cut)) break; if (!zone) { auth = 0; continue; } } for (rec = daemon->mxnames; rec; rec = rec->next) if (!rec->issrv && hostname_isequal(name, rec->name)) { nxdomain = 0; if (qtype == T_MX) { found = 1; log_query(F_CONFIG | F_RRNAME, name, NULL, ""); if (add_resource_record(header, limit, &trunc, nameoffset, &ansp, daemon->auth_ttl, NULL, T_MX, C_IN, "sd", rec->weight, rec->target)) anscount++; } } for (move = NULL, up = &daemon->mxnames, rec = daemon->mxnames; rec; rec = rec->next) if (rec->issrv && hostname_isequal(name, rec->name)) { nxdomain = 0; if (qtype == T_SRV) { found = 1; log_query(F_CONFIG | F_RRNAME, name, NULL, ""); if (add_resource_record(header, limit, &trunc, nameoffset, &ansp, daemon->auth_ttl, NULL, T_SRV, C_IN, "sssd", rec->priority, rec->weight, rec->srvport, rec->target)) anscount++; } /* unlink first SRV record found */ if (!move) { move = rec; *up = rec->next; } else up = &rec->next; } else up = &rec->next; /* put first SRV record back at the end. */ if (move) { *up = move; move->next = NULL; } for (txt = daemon->rr; txt; txt = txt->next) if (hostname_isequal(name, txt->name)) { nxdomain = 0; if (txt->class == qtype) { found = 1; log_query(F_CONFIG | F_RRNAME, name, NULL, ""); if (add_resource_record(header, limit, &trunc, nameoffset, &ansp, daemon->auth_ttl, NULL, txt->class, C_IN, "t", txt->len, txt->txt)) anscount++; } } for (txt = daemon->txt; txt; txt = txt->next) if (txt->class == C_IN && hostname_isequal(name, txt->name)) { nxdomain = 0; if (qtype == T_TXT) { found = 1; log_query(F_CONFIG | F_RRNAME, name, NULL, ""); if (add_resource_record(header, limit, &trunc, nameoffset, &ansp, daemon->auth_ttl, NULL, T_TXT, C_IN, "t", txt->len, txt->txt)) anscount++; } } for (na = daemon->naptr; na; na = na->next) if (hostname_isequal(name, na->name)) { nxdomain = 0; if (qtype == T_NAPTR) { found = 1; log_query(F_CONFIG | F_RRNAME, name, NULL, ""); if (add_resource_record(header, limit, &trunc, nameoffset, &ansp, daemon->auth_ttl, NULL, T_NAPTR, C_IN, "sszzzd", na->order, na->pref, na->flags, na->services, na->regexp, na->replace)) anscount++; } } if (qtype == T_A) flag = F_IPV4; #ifdef HAVE_IPV6 if (qtype == T_AAAA) flag = F_IPV6; #endif for (intr = daemon->int_names; intr; intr = intr->next) if (hostname_isequal(name, intr->name)) { struct addrlist *addrlist; nxdomain = 0; if (flag) for (addrlist = intr->addr; addrlist; addrlist = addrlist->next) if (((addrlist->flags & ADDRLIST_IPV6) ? T_AAAA : T_A) == qtype && (local_query || filter_zone(zone, flag, &addrlist->addr))) { #ifdef HAVE_IPV6 if (addrlist->flags & ADDRLIST_REVONLY) continue; #endif found = 1; log_query(F_FORWARD | F_CONFIG | flag, name, &addrlist->addr, NULL); if (add_resource_record(header, limit, &trunc, nameoffset, &ansp, daemon->auth_ttl, NULL, qtype, C_IN, qtype == T_A ? "4" : "6", &addrlist->addr)) anscount++; } } for (a = daemon->cnames; a; a = a->next) if (hostname_isequal(name, a->alias) ) { log_query(F_CONFIG | F_CNAME, name, NULL, NULL); strcpy(name, a->target); if (!strchr(name, '.')) { strcat(name, "."); strcat(name, zone->domain); } found = 1; if (add_resource_record(header, limit, &trunc, nameoffset, &ansp, daemon->auth_ttl, &nameoffset, T_CNAME, C_IN, "d", name)) anscount++; goto cname_restart; } if (!cut) { nxdomain = 0; if (qtype == T_SOA) { auth = soa = 1; /* inhibits auth section */ found = 1; log_query(F_RRNAME | F_AUTH, zone->domain, NULL, ""); } else if (qtype == T_AXFR) { struct iname *peers; if (peer_addr->sa.sa_family == AF_INET) peer_addr->in.sin_port = 0; #ifdef HAVE_IPV6 else { peer_addr->in6.sin6_port = 0; peer_addr->in6.sin6_scope_id = 0; } #endif for (peers = daemon->auth_peers; peers; peers = peers->next) if (sockaddr_isequal(peer_addr, &peers->addr)) break; /* Refuse all AXFR unless --auth-sec-servers is set */ if ((!peers && daemon->auth_peers) || !daemon->secondary_forward_server) { if (peer_addr->sa.sa_family == AF_INET) inet_ntop(AF_INET, &peer_addr->in.sin_addr, daemon->addrbuff, ADDRSTRLEN); #ifdef HAVE_IPV6 else inet_ntop(AF_INET6, &peer_addr->in6.sin6_addr, daemon->addrbuff, ADDRSTRLEN); #endif my_syslog(LOG_WARNING, _("ignoring zone transfer request from %s"), daemon->addrbuff); return 0; } auth = 1; soa = 1; /* inhibits auth section */ ns = 1; /* ensure we include NS records! */ axfr = 1; found = 1; axfroffset = nameoffset; log_query(F_RRNAME | F_AUTH, zone->domain, NULL, ""); } else if (qtype == T_NS) { auth = 1; ns = 1; /* inhibits auth section */ found = 1; log_query(F_RRNAME | F_AUTH, zone->domain, NULL, ""); } } if (!option_bool(OPT_DHCP_FQDN) && cut) { *cut = 0; /* remove domain part */ if (!strchr(name, '.') && (crecp = cache_find_by_name(NULL, name, now, F_IPV4 | F_IPV6))) { if (crecp->flags & F_DHCP) do { nxdomain = 0; if ((crecp->flags & flag) && (local_query || filter_zone(zone, flag, &(crecp->addr.addr)))) { *cut = '.'; /* restore domain part */ log_query(crecp->flags, name, &crecp->addr.addr, record_source(crecp->uid)); *cut = 0; /* remove domain part */ found = 1; if (add_resource_record(header, limit, &trunc, nameoffset, &ansp, daemon->auth_ttl, NULL, qtype, C_IN, qtype == T_A ? "4" : "6", &crecp->addr)) anscount++; } } while ((crecp = cache_find_by_name(crecp, name, now, F_IPV4 | F_IPV6))); } *cut = '.'; /* restore domain part */ } if ((crecp = cache_find_by_name(NULL, name, now, F_IPV4 | F_IPV6))) { if ((crecp->flags & F_HOSTS) || (((crecp->flags & F_DHCP) && option_bool(OPT_DHCP_FQDN)))) do { nxdomain = 0; if ((crecp->flags & flag) && (local_query || filter_zone(zone, flag, &(crecp->addr.addr)))) { log_query(crecp->flags, name, &crecp->addr.addr, record_source(crecp->uid)); found = 1; if (add_resource_record(header, limit, &trunc, nameoffset, &ansp, daemon->auth_ttl, NULL, qtype, C_IN, qtype == T_A ? "4" : "6", &crecp->addr)) anscount++; } } while ((crecp = cache_find_by_name(crecp, name, now, F_IPV4 | F_IPV6))); } if (!found) log_query(flag | F_NEG | (nxdomain ? F_NXDOMAIN : 0) | F_FORWARD | F_AUTH, name, NULL, NULL); } /* Add auth section */ if (auth && zone) { char *authname; int newoffset, offset = 0; if (!subnet) authname = zone->domain; else { /* handle NS and SOA for PTR records */ authname = name; if (!(subnet->flags & ADDRLIST_IPV6)) { in_addr_t a = ntohl(subnet->addr.addr.addr4.s_addr) >> 8; char *p = name; if (subnet->prefixlen >= 24) p += sprintf(p, "%d.", a & 0xff); a = a >> 8; if (subnet->prefixlen >= 16 ) p += sprintf(p, "%d.", a & 0xff); a = a >> 8; p += sprintf(p, "%d.in-addr.arpa", a & 0xff); } #ifdef HAVE_IPV6 else { char *p = name; int i; for (i = subnet->prefixlen-1; i >= 0; i -= 4) { int dig = ((unsigned char *)&subnet->addr.addr.addr6)[i>>3]; p += sprintf(p, "%.1x.", (i>>2) & 1 ? dig & 15 : dig >> 4); } p += sprintf(p, "ip6.arpa"); } #endif } /* handle NS and SOA in auth section or for explicit queries */ newoffset = ansp - (unsigned char *)header; if (((anscount == 0 && !ns) || soa) && add_resource_record(header, limit, &trunc, 0, &ansp, daemon->auth_ttl, NULL, T_SOA, C_IN, "ddlllll", authname, daemon->authserver, daemon->hostmaster, daemon->soa_sn, daemon->soa_refresh, daemon->soa_retry, daemon->soa_expiry, daemon->auth_ttl)) { offset = newoffset; if (soa) anscount++; else authcount++; } if (anscount != 0 || ns) { struct name_list *secondary; newoffset = ansp - (unsigned char *)header; if (add_resource_record(header, limit, &trunc, -offset, &ansp, daemon->auth_ttl, NULL, T_NS, C_IN, "d", offset == 0 ? authname : NULL, daemon->authserver)) { if (offset == 0) offset = newoffset; if (ns) anscount++; else authcount++; } if (!subnet) for (secondary = daemon->secondary_forward_server; secondary; secondary = secondary->next) if (add_resource_record(header, limit, &trunc, offset, &ansp, daemon->auth_ttl, NULL, T_NS, C_IN, "d", secondary->name)) { if (ns) anscount++; else authcount++; } } if (axfr) { for (rec = daemon->mxnames; rec; rec = rec->next) if (in_zone(zone, rec->name, &cut)) { if (cut) *cut = 0; if (rec->issrv) { if (add_resource_record(header, limit, &trunc, -axfroffset, &ansp, daemon->auth_ttl, NULL, T_SRV, C_IN, "sssd", cut ? rec->name : NULL, rec->priority, rec->weight, rec->srvport, rec->target)) anscount++; } else { if (add_resource_record(header, limit, &trunc, -axfroffset, &ansp, daemon->auth_ttl, NULL, T_MX, C_IN, "sd", cut ? rec->name : NULL, rec->weight, rec->target)) anscount++; } /* restore config data */ if (cut) *cut = '.'; } for (txt = daemon->rr; txt; txt = txt->next) if (in_zone(zone, txt->name, &cut)) { if (cut) *cut = 0; if (add_resource_record(header, limit, &trunc, -axfroffset, &ansp, daemon->auth_ttl, NULL, txt->class, C_IN, "t", cut ? txt->name : NULL, txt->len, txt->txt)) anscount++; /* restore config data */ if (cut) *cut = '.'; } for (txt = daemon->txt; txt; txt = txt->next) if (txt->class == C_IN && in_zone(zone, txt->name, &cut)) { if (cut) *cut = 0; if (add_resource_record(header, limit, &trunc, -axfroffset, &ansp, daemon->auth_ttl, NULL, T_TXT, C_IN, "t", cut ? txt->name : NULL, txt->len, txt->txt)) anscount++; /* restore config data */ if (cut) *cut = '.'; } for (na = daemon->naptr; na; na = na->next) if (in_zone(zone, na->name, &cut)) { if (cut) *cut = 0; if (add_resource_record(header, limit, &trunc, -axfroffset, &ansp, daemon->auth_ttl, NULL, T_NAPTR, C_IN, "sszzzd", cut ? na->name : NULL, na->order, na->pref, na->flags, na->services, na->regexp, na->replace)) anscount++; /* restore config data */ if (cut) *cut = '.'; } for (intr = daemon->int_names; intr; intr = intr->next) if (in_zone(zone, intr->name, &cut)) { struct addrlist *addrlist; if (cut) *cut = 0; for (addrlist = intr->addr; addrlist; addrlist = addrlist->next) if (!(addrlist->flags & ADDRLIST_IPV6) && (local_query || filter_zone(zone, F_IPV4, &addrlist->addr)) && add_resource_record(header, limit, &trunc, -axfroffset, &ansp, daemon->auth_ttl, NULL, T_A, C_IN, "4", cut ? intr->name : NULL, &addrlist->addr)) anscount++; #ifdef HAVE_IPV6 for (addrlist = intr->addr; addrlist; addrlist = addrlist->next) if ((addrlist->flags & ADDRLIST_IPV6) && (local_query || filter_zone(zone, F_IPV6, &addrlist->addr)) && add_resource_record(header, limit, &trunc, -axfroffset, &ansp, daemon->auth_ttl, NULL, T_AAAA, C_IN, "6", cut ? intr->name : NULL, &addrlist->addr)) anscount++; #endif /* restore config data */ if (cut) *cut = '.'; } for (a = daemon->cnames; a; a = a->next) if (in_zone(zone, a->alias, &cut)) { strcpy(name, a->target); if (!strchr(name, '.')) { strcat(name, "."); strcat(name, zone->domain); } if (cut) *cut = 0; if (add_resource_record(header, limit, &trunc, -axfroffset, &ansp, daemon->auth_ttl, NULL, T_CNAME, C_IN, "d", cut ? a->alias : NULL, name)) anscount++; } cache_enumerate(1); while ((crecp = cache_enumerate(0))) { if ((crecp->flags & (F_IPV4 | F_IPV6)) && !(crecp->flags & (F_NEG | F_NXDOMAIN)) && (crecp->flags & F_FORWARD)) { if ((crecp->flags & F_DHCP) && !option_bool(OPT_DHCP_FQDN)) { char *cache_name = cache_get_name(crecp); if (!strchr(cache_name, '.') && (local_query || filter_zone(zone, (crecp->flags & (F_IPV6 | F_IPV4)), &(crecp->addr.addr)))) { qtype = T_A; #ifdef HAVE_IPV6 if (crecp->flags & F_IPV6) qtype = T_AAAA; #endif if (add_resource_record(header, limit, &trunc, -axfroffset, &ansp, daemon->auth_ttl, NULL, qtype, C_IN, (crecp->flags & F_IPV4) ? "4" : "6", cache_name, &crecp->addr)) anscount++; } } if ((crecp->flags & F_HOSTS) || (((crecp->flags & F_DHCP) && option_bool(OPT_DHCP_FQDN)))) { strcpy(name, cache_get_name(crecp)); if (in_zone(zone, name, &cut) && (local_query || filter_zone(zone, (crecp->flags & (F_IPV6 | F_IPV4)), &(crecp->addr.addr)))) { qtype = T_A; #ifdef HAVE_IPV6 if (crecp->flags & F_IPV6) qtype = T_AAAA; #endif if (cut) *cut = 0; if (add_resource_record(header, limit, &trunc, -axfroffset, &ansp, daemon->auth_ttl, NULL, qtype, C_IN, (crecp->flags & F_IPV4) ? "4" : "6", cut ? name : NULL, &crecp->addr)) anscount++; } } } } /* repeat SOA as last record */ if (add_resource_record(header, limit, &trunc, axfroffset, &ansp, daemon->auth_ttl, NULL, T_SOA, C_IN, "ddlllll", daemon->authserver, daemon->hostmaster, daemon->soa_sn, daemon->soa_refresh, daemon->soa_retry, daemon->soa_expiry, daemon->auth_ttl)) anscount++; } } /* done all questions, set up header and return length of result */ /* clear authoritative and truncated flags, set QR flag */ header->hb3 = (header->hb3 & ~(HB3_AA | HB3_TC)) | HB3_QR; if (local_query) { /* set RA flag */ header->hb4 |= HB4_RA; } else { /* clear RA flag */ header->hb4 &= ~HB4_RA; } /* authoritive */ if (auth) header->hb3 |= HB3_AA; /* truncation */ if (trunc) header->hb3 |= HB3_TC; if ((auth || local_query) && nxdomain) SET_RCODE(header, NXDOMAIN); else SET_RCODE(header, NOERROR); /* no error */ header->ancount = htons(anscount); header->nscount = htons(authcount); header->arcount = htons(0); /* Advertise our packet size limit in our reply */ if (have_pseudoheader) return add_pseudoheader(header, ansp - (unsigned char *)header, (unsigned char *)limit, daemon->edns_pktsz, 0, NULL, 0, do_bit, 0); return ansp - (unsigned char *)header; } #endif