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/*
Unix SMB/CIFS implementation.
DNS server handler for queries
Copyright (C) 2010 Kai Blin <kai@samba.org>
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; either version 3 of the License, or
(at your option) any later version.
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 <http://www.gnu.org/licenses/>.
*/
#include "includes.h"
#include "smbd/service_task.h"
#include "libcli/util/werror.h"
#include "librpc/ndr/libndr.h"
#include "librpc/gen_ndr/ndr_dns.h"
#include "librpc/gen_ndr/ndr_dnsp.h"
#include <ldb.h>
#include "param/param.h"
#include "dsdb/samdb/samdb.h"
#include "dsdb/common/util.h"
#include "dns_server/dns_server.h"
#include "libcli/dns/libdns.h"
#include "lib/util/dlinklist.h"
#include "lib/util/util_net.h"
#include "lib/util/tevent_werror.h"
#include "auth/auth.h"
#include "auth/credentials/credentials.h"
#include "auth/gensec/gensec.h"
#undef DBGC_CLASS
#define DBGC_CLASS DBGC_DNS
#define MAX_Q_RECURSION_DEPTH 20
struct forwarder_string {
const char *forwarder;
struct forwarder_string *prev, *next;
};
static WERROR add_response_rr(const char *name,
const struct dnsp_DnssrvRpcRecord *rec,
struct dns_res_rec **answers)
{
struct dns_res_rec *ans = *answers;
uint16_t ai = talloc_array_length(ans);
enum ndr_err_code ndr_err;
if (ai == UINT16_MAX) {
return WERR_BUFFER_OVERFLOW;
}
/*
* "ans" is always non-NULL and thus its own talloc context
*/
ans = talloc_realloc(ans, ans, struct dns_res_rec, ai+1);
if (ans == NULL) {
return WERR_NOMEM;
}
ZERO_STRUCT(ans[ai]);
switch (rec->wType) {
case DNS_QTYPE_CNAME:
ans[ai].rdata.cname_record = talloc_strdup(ans, rec->data.cname);
W_ERROR_HAVE_NO_MEMORY(ans[ai].rdata.cname_record);
break;
case DNS_QTYPE_A:
ans[ai].rdata.ipv4_record = talloc_strdup(ans, rec->data.ipv4);
W_ERROR_HAVE_NO_MEMORY(ans[ai].rdata.ipv4_record);
break;
case DNS_QTYPE_AAAA:
ans[ai].rdata.ipv6_record = talloc_strdup(ans, rec->data.ipv6);
W_ERROR_HAVE_NO_MEMORY(ans[ai].rdata.ipv6_record);
break;
case DNS_TYPE_NS:
ans[ai].rdata.ns_record = talloc_strdup(ans, rec->data.ns);
W_ERROR_HAVE_NO_MEMORY(ans[ai].rdata.ns_record);
break;
case DNS_QTYPE_SRV:
ans[ai].rdata.srv_record.priority = rec->data.srv.wPriority;
ans[ai].rdata.srv_record.weight = rec->data.srv.wWeight;
ans[ai].rdata.srv_record.port = rec->data.srv.wPort;
ans[ai].rdata.srv_record.target = talloc_strdup(
ans, rec->data.srv.nameTarget);
W_ERROR_HAVE_NO_MEMORY(ans[ai].rdata.srv_record.target);
break;
case DNS_QTYPE_SOA:
ans[ai].rdata.soa_record.mname = talloc_strdup(
ans, rec->data.soa.mname);
W_ERROR_HAVE_NO_MEMORY(ans[ai].rdata.soa_record.mname);
ans[ai].rdata.soa_record.rname = talloc_strdup(
ans, rec->data.soa.rname);
W_ERROR_HAVE_NO_MEMORY(ans[ai].rdata.soa_record.rname);
ans[ai].rdata.soa_record.serial = rec->data.soa.serial;
ans[ai].rdata.soa_record.refresh = rec->data.soa.refresh;
ans[ai].rdata.soa_record.retry = rec->data.soa.retry;
ans[ai].rdata.soa_record.expire = rec->data.soa.expire;
ans[ai].rdata.soa_record.minimum = rec->data.soa.minimum;
break;
case DNS_QTYPE_PTR:
ans[ai].rdata.ptr_record = talloc_strdup(ans, rec->data.ptr);
W_ERROR_HAVE_NO_MEMORY(ans[ai].rdata.ptr_record);
break;
case DNS_QTYPE_MX:
ans[ai].rdata.mx_record.preference = rec->data.mx.wPriority;
ans[ai].rdata.mx_record.exchange = talloc_strdup(
ans, rec->data.mx.nameTarget);
if (ans[ai].rdata.mx_record.exchange == NULL) {
return WERR_NOMEM;
}
break;
case DNS_QTYPE_TXT:
ndr_err = ndr_dnsp_string_list_copy(ans,
&rec->data.txt,
&ans[ai].rdata.txt_record.txt);
if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
return WERR_NOMEM;
}
break;
default:
DEBUG(0, ("Got unhandled type %u query.\n", rec->wType));
return DNS_ERR(NOT_IMPLEMENTED);
}
ans[ai].name = talloc_strdup(ans, name);
W_ERROR_HAVE_NO_MEMORY(ans[ai].name);
ans[ai].rr_type = rec->wType;
ans[ai].rr_class = DNS_QCLASS_IN;
ans[ai].ttl = rec->dwTtlSeconds;
ans[ai].length = UINT16_MAX;
*answers = ans;
return WERR_OK;
}
static WERROR add_dns_res_rec(struct dns_res_rec **pdst,
const struct dns_res_rec *src)
{
struct dns_res_rec *dst = *pdst;
uint16_t di = talloc_array_length(dst);
enum ndr_err_code ndr_err;
if (di == UINT16_MAX) {
return WERR_BUFFER_OVERFLOW;
}
dst = talloc_realloc(dst, dst, struct dns_res_rec, di+1);
if (dst == NULL) {
return WERR_NOMEM;
}
ZERO_STRUCT(dst[di]);
dst[di] = (struct dns_res_rec) {
.name = talloc_strdup(dst, src->name),
.rr_type = src->rr_type,
.rr_class = src->rr_class,
.ttl = src->ttl,
.length = src->length
};
if (dst[di].name == NULL) {
return WERR_NOMEM;
}
switch (src->rr_type) {
case DNS_QTYPE_CNAME:
dst[di].rdata.cname_record = talloc_strdup(
dst, src->rdata.cname_record);
if (dst[di].rdata.cname_record == NULL) {
return WERR_NOMEM;
}
break;
case DNS_QTYPE_A:
dst[di].rdata.ipv4_record = talloc_strdup(
dst, src->rdata.ipv4_record);
if (dst[di].rdata.ipv4_record == NULL) {
return WERR_NOMEM;
}
break;
case DNS_QTYPE_AAAA:
dst[di].rdata.ipv6_record = talloc_strdup(
dst, src->rdata.ipv6_record);
if (dst[di].rdata.ipv6_record == NULL) {
return WERR_NOMEM;
}
break;
case DNS_TYPE_NS:
dst[di].rdata.ns_record = talloc_strdup(
dst, src->rdata.ns_record);
if (dst[di].rdata.ns_record == NULL) {
return WERR_NOMEM;
}
break;
case DNS_QTYPE_SRV:
dst[di].rdata.srv_record = (struct dns_srv_record) {
.priority = src->rdata.srv_record.priority,
.weight = src->rdata.srv_record.weight,
.port = src->rdata.srv_record.port,
.target = talloc_strdup(
dst, src->rdata.srv_record.target)
};
if (dst[di].rdata.srv_record.target == NULL) {
return WERR_NOMEM;
}
break;
case DNS_QTYPE_SOA:
dst[di].rdata.soa_record = (struct dns_soa_record) {
.mname = talloc_strdup(
dst, src->rdata.soa_record.mname),
.rname = talloc_strdup(
dst, src->rdata.soa_record.rname),
.serial = src->rdata.soa_record.serial,
.refresh = src->rdata.soa_record.refresh,
.retry = src->rdata.soa_record.retry,
.expire = src->rdata.soa_record.expire,
.minimum = src->rdata.soa_record.minimum
};
if ((dst[di].rdata.soa_record.mname == NULL) ||
(dst[di].rdata.soa_record.rname == NULL)) {
return WERR_NOMEM;
}
break;
case DNS_QTYPE_PTR:
dst[di].rdata.ptr_record = talloc_strdup(
dst, src->rdata.ptr_record);
if (dst[di].rdata.ptr_record == NULL) {
return WERR_NOMEM;
}
break;
case DNS_QTYPE_MX:
dst[di].rdata.mx_record = (struct dns_mx_record) {
.preference = src->rdata.mx_record.preference,
.exchange = talloc_strdup(
src, src->rdata.mx_record.exchange)
};
if (dst[di].rdata.mx_record.exchange == NULL) {
return WERR_NOMEM;
}
break;
case DNS_QTYPE_TXT:
ndr_err = ndr_dnsp_string_list_copy(dst,
&src->rdata.txt_record.txt,
&dst[di].rdata.txt_record.txt);
if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
return WERR_NOMEM;
}
break;
default:
DBG_WARNING("Got unhandled type %u query.\n", src->rr_type);
return DNS_ERR(NOT_IMPLEMENTED);
}
*pdst = dst;
return WERR_OK;
}
struct ask_forwarder_state {
struct tevent_context *ev;
uint16_t id;
struct dns_name_packet in_packet;
};
static void ask_forwarder_done(struct tevent_req *subreq);
static struct tevent_req *ask_forwarder_send(
TALLOC_CTX *mem_ctx, struct tevent_context *ev,
struct dns_server *dns,
const char *forwarder, struct dns_name_question *question)
{
struct tevent_req *req, *subreq;
struct ask_forwarder_state *state;
struct dns_res_rec *options;
struct dns_name_packet out_packet = { 0, };
DATA_BLOB out_blob;
enum ndr_err_code ndr_err;
WERROR werr;
req = tevent_req_create(mem_ctx, &state, struct ask_forwarder_state);
if (req == NULL) {
return NULL;
}
state->ev = ev;
generate_random_buffer((uint8_t *)&state->id, sizeof(state->id));
if (!is_ipaddress(forwarder)) {
DEBUG(0, ("Invalid 'dns forwarder' setting '%s', needs to be "
"an IP address\n", forwarder));
tevent_req_werror(req, DNS_ERR(NAME_ERROR));
return tevent_req_post(req, ev);
}
out_packet.id = state->id;
out_packet.operation |= DNS_OPCODE_QUERY | DNS_FLAG_RECURSION_DESIRED;
out_packet.qdcount = 1;
out_packet.questions = question;
werr = dns_generate_options(dns, state, &options);
if (!W_ERROR_IS_OK(werr)) {
tevent_req_werror(req, werr);
return tevent_req_post(req, ev);
}
out_packet.arcount = 1;
out_packet.additional = options;
ndr_err = ndr_push_struct_blob(
&out_blob, state, &out_packet,
(ndr_push_flags_fn_t)ndr_push_dns_name_packet);
if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
tevent_req_werror(req, DNS_ERR(SERVER_FAILURE));
return tevent_req_post(req, ev);
}
subreq = dns_udp_request_send(state, ev, forwarder, out_blob.data,
out_blob.length);
if (tevent_req_nomem(subreq, req)) {
return tevent_req_post(req, ev);
}
tevent_req_set_callback(subreq, ask_forwarder_done, req);
return req;
}
static void ask_forwarder_done(struct tevent_req *subreq)
{
struct tevent_req *req = tevent_req_callback_data(
subreq, struct tevent_req);
struct ask_forwarder_state *state = tevent_req_data(
req, struct ask_forwarder_state);
DATA_BLOB in_blob;
enum ndr_err_code ndr_err;
int ret;
ret = dns_udp_request_recv(subreq, state,
&in_blob.data, &in_blob.length);
TALLOC_FREE(subreq);
if (ret != 0) {
tevent_req_werror(req, unix_to_werror(ret));
return;
}
ndr_err = ndr_pull_struct_blob(
&in_blob, state, &state->in_packet,
(ndr_pull_flags_fn_t)ndr_pull_dns_name_packet);
if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
tevent_req_werror(req, DNS_ERR(SERVER_FAILURE));
return;
}
if (state->in_packet.id != state->id) {
tevent_req_werror(req, DNS_ERR(NAME_ERROR));
return;
}
tevent_req_done(req);
}
static WERROR ask_forwarder_recv(
struct tevent_req *req, TALLOC_CTX *mem_ctx,
struct dns_res_rec **answers, uint16_t *ancount,
struct dns_res_rec **nsrecs, uint16_t *nscount,
struct dns_res_rec **additional, uint16_t *arcount)
{
struct ask_forwarder_state *state = tevent_req_data(
req, struct ask_forwarder_state);
struct dns_name_packet *in_packet = &state->in_packet;
WERROR err;
if (tevent_req_is_werror(req, &err)) {
return err;
}
*ancount = in_packet->ancount;
*answers = talloc_move(mem_ctx, &in_packet->answers);
*nscount = in_packet->nscount;
*nsrecs = talloc_move(mem_ctx, &in_packet->nsrecs);
*arcount = in_packet->arcount;
*additional = talloc_move(mem_ctx, &in_packet->additional);
return WERR_OK;
}
static WERROR add_zone_authority_record(struct dns_server *dns,
TALLOC_CTX *mem_ctx,
const struct dns_name_question *question,
struct dns_res_rec **nsrecs)
{
const char *zone = NULL;
struct dnsp_DnssrvRpcRecord *recs;
struct dns_res_rec *ns = *nsrecs;
uint16_t rec_count;
struct ldb_dn *dn = NULL;
unsigned int ri;
WERROR werror;
zone = dns_get_authoritative_zone(dns, question->name);
DEBUG(10, ("Creating zone authority record for '%s'\n", zone));
werror = dns_name2dn(dns, mem_ctx, zone, &dn);
if (!W_ERROR_IS_OK(werror)) {
return werror;
}
werror = dns_lookup_records(dns, mem_ctx, dn, &recs, &rec_count);
if (!W_ERROR_IS_OK(werror)) {
return werror;
}
for (ri = 0; ri < rec_count; ri++) {
if (recs[ri].wType == DNS_TYPE_SOA) {
werror = add_response_rr(zone, &recs[ri], &ns);
if (!W_ERROR_IS_OK(werror)) {
return werror;
}
}
}
*nsrecs = ns;
return WERR_OK;
}
static struct tevent_req *handle_authoritative_send(
TALLOC_CTX *mem_ctx, struct tevent_context *ev,
struct dns_server *dns, const char *forwarder,
struct dns_name_question *question,
struct dns_res_rec **answers, struct dns_res_rec **nsrecs,
size_t cname_depth);
static WERROR handle_authoritative_recv(struct tevent_req *req);
struct handle_dnsrpcrec_state {
struct dns_res_rec **answers;
struct dns_res_rec **nsrecs;
};
static void handle_dnsrpcrec_gotauth(struct tevent_req *subreq);
static void handle_dnsrpcrec_gotforwarded(struct tevent_req *subreq);
static struct tevent_req *handle_dnsrpcrec_send(
TALLOC_CTX *mem_ctx, struct tevent_context *ev,
struct dns_server *dns, const char *forwarder,
const struct dns_name_question *question,
struct dnsp_DnssrvRpcRecord *rec,
struct dns_res_rec **answers, struct dns_res_rec **nsrecs,
size_t cname_depth)
{
struct tevent_req *req, *subreq;
struct handle_dnsrpcrec_state *state;
struct dns_name_question *new_q;
bool resolve_cname;
WERROR werr;
req = tevent_req_create(mem_ctx, &state,
struct handle_dnsrpcrec_state);
if (req == NULL) {
return NULL;
}
state->answers = answers;
state->nsrecs = nsrecs;
if (cname_depth >= MAX_Q_RECURSION_DEPTH) {
tevent_req_done(req);
return tevent_req_post(req, ev);
}
resolve_cname = ((rec->wType == DNS_TYPE_CNAME) &&
((question->question_type == DNS_QTYPE_A) ||
(question->question_type == DNS_QTYPE_AAAA)));
if (!resolve_cname) {
if ((question->question_type != DNS_QTYPE_ALL) &&
(rec->wType !=
(enum dns_record_type) question->question_type)) {
tevent_req_done(req);
return tevent_req_post(req, ev);
}
werr = add_response_rr(question->name, rec, state->answers);
if (tevent_req_werror(req, werr)) {
return tevent_req_post(req, ev);
}
tevent_req_done(req);
return tevent_req_post(req, ev);
}
werr = add_response_rr(question->name, rec, state->answers);
if (tevent_req_werror(req, werr)) {
return tevent_req_post(req, ev);
}
new_q = talloc(state, struct dns_name_question);
if (tevent_req_nomem(new_q, req)) {
return tevent_req_post(req, ev);
}
*new_q = (struct dns_name_question) {
.question_type = question->question_type,
.question_class = question->question_class,
.name = rec->data.cname
};
if (dns_authoritative_for_zone(dns, new_q->name)) {
subreq = handle_authoritative_send(
state, ev, dns, forwarder, new_q,
state->answers, state->nsrecs,
cname_depth + 1);
if (tevent_req_nomem(subreq, req)) {
return tevent_req_post(req, ev);
}
tevent_req_set_callback(subreq, handle_dnsrpcrec_gotauth, req);
return req;
}
subreq = ask_forwarder_send(state, ev, dns, forwarder, new_q);
if (tevent_req_nomem(subreq, req)) {
return tevent_req_post(req, ev);
}
tevent_req_set_callback(subreq, handle_dnsrpcrec_gotforwarded, req);
return req;
}
static void handle_dnsrpcrec_gotauth(struct tevent_req *subreq)
{
struct tevent_req *req = tevent_req_callback_data(
subreq, struct tevent_req);
WERROR werr;
werr = handle_authoritative_recv(subreq);
TALLOC_FREE(subreq);
if (tevent_req_werror(req, werr)) {
return;
}
tevent_req_done(req);
}
static void handle_dnsrpcrec_gotforwarded(struct tevent_req *subreq)
{
struct tevent_req *req = tevent_req_callback_data(
subreq, struct tevent_req);
struct handle_dnsrpcrec_state *state = tevent_req_data(
req, struct handle_dnsrpcrec_state);
struct dns_res_rec *answers, *nsrecs, *additional;
uint16_t ancount = 0;
uint16_t nscount = 0;
uint16_t arcount = 0;
uint16_t i;
WERROR werr;
werr = ask_forwarder_recv(subreq, state, &answers, &ancount,
&nsrecs, &nscount, &additional, &arcount);
if (tevent_req_werror(req, werr)) {
return;
}
for (i=0; i<ancount; i++) {
werr = add_dns_res_rec(state->answers, &answers[i]);
if (tevent_req_werror(req, werr)) {
return;
}
}
for (i=0; i<nscount; i++) {
werr = add_dns_res_rec(state->nsrecs, &nsrecs[i]);
if (tevent_req_werror(req, werr)) {
return;
}
}
tevent_req_done(req);
}
static WERROR handle_dnsrpcrec_recv(struct tevent_req *req)
{
return tevent_req_simple_recv_werror(req);
}
struct handle_authoritative_state {
struct tevent_context *ev;
struct dns_server *dns;
struct dns_name_question *question;
const char *forwarder;
struct dnsp_DnssrvRpcRecord *recs;
uint16_t rec_count;
uint16_t recs_done;
struct dns_res_rec **answers;
struct dns_res_rec **nsrecs;
size_t cname_depth;
};
static void handle_authoritative_done(struct tevent_req *subreq);
static struct tevent_req *handle_authoritative_send(
TALLOC_CTX *mem_ctx, struct tevent_context *ev,
struct dns_server *dns, const char *forwarder,
struct dns_name_question *question,
struct dns_res_rec **answers, struct dns_res_rec **nsrecs,
size_t cname_depth)
{
struct tevent_req *req, *subreq;
struct handle_authoritative_state *state;
struct ldb_dn *dn = NULL;
WERROR werr;
req = tevent_req_create(mem_ctx, &state,
struct handle_authoritative_state);
if (req == NULL) {
return NULL;
}
state->ev = ev;
state->dns = dns;
state->question = question;
state->forwarder = forwarder;
state->answers = answers;
state->nsrecs = nsrecs;
state->cname_depth = cname_depth;
werr = dns_name2dn(dns, state, question->name, &dn);
if (tevent_req_werror(req, werr)) {
return tevent_req_post(req, ev);
}
werr = dns_lookup_records(dns, state, dn, &state->recs,
&state->rec_count);
TALLOC_FREE(dn);
if (tevent_req_werror(req, werr)) {
return tevent_req_post(req, ev);
}
if (state->rec_count == 0) {
tevent_req_werror(req, DNS_ERR(NAME_ERROR));
return tevent_req_post(req, ev);
}
subreq = handle_dnsrpcrec_send(
state, state->ev, state->dns, state->forwarder,
state->question, &state->recs[state->recs_done],
state->answers, state->nsrecs,
state->cname_depth);
if (tevent_req_nomem(subreq, req)) {
return tevent_req_post(req, ev);
}
tevent_req_set_callback(subreq, handle_authoritative_done, req);
return req;
}
static void handle_authoritative_done(struct tevent_req *subreq)
{
struct tevent_req *req = tevent_req_callback_data(
subreq, struct tevent_req);
struct handle_authoritative_state *state = tevent_req_data(
req, struct handle_authoritative_state);
WERROR werr;
werr = handle_dnsrpcrec_recv(subreq);
TALLOC_FREE(subreq);
if (tevent_req_werror(req, werr)) {
return;
}
state->recs_done += 1;
if (state->recs_done == state->rec_count) {
tevent_req_done(req);
return;
}
subreq = handle_dnsrpcrec_send(
state, state->ev, state->dns, state->forwarder,
state->question, &state->recs[state->recs_done],
state->answers, state->nsrecs,
state->cname_depth);
if (tevent_req_nomem(subreq, req)) {
return;
}
tevent_req_set_callback(subreq, handle_authoritative_done, req);
}
static WERROR handle_authoritative_recv(struct tevent_req *req)
{
struct handle_authoritative_state *state = tevent_req_data(
req, struct handle_authoritative_state);
WERROR werr;
if (tevent_req_is_werror(req, &werr)) {
return werr;
}
werr = add_zone_authority_record(state->dns, state, state->question,
state->nsrecs);
if (!W_ERROR_IS_OK(werr)) {
return werr;
}
return WERR_OK;
}
static NTSTATUS create_tkey(struct dns_server *dns,
const char* name,
const char* algorithm,
struct dns_server_tkey **tkey)
{
NTSTATUS status;
struct dns_server_tkey_store *store = dns->tkeys;
struct dns_server_tkey *k = talloc_zero(store, struct dns_server_tkey);
if (k == NULL) {
return NT_STATUS_NO_MEMORY;
}
k->name = talloc_strdup(k, name);
if (k->name == NULL) {
return NT_STATUS_NO_MEMORY;
}
k->algorithm = talloc_strdup(k, algorithm);
if (k->algorithm == NULL) {
return NT_STATUS_NO_MEMORY;
}
status = samba_server_gensec_start(k,
dns->task->event_ctx,
dns->task->msg_ctx,
dns->task->lp_ctx,
dns->server_credentials,
"dns",
&k->gensec);
if (!NT_STATUS_IS_OK(status)) {
DEBUG(1, ("Failed to start GENSEC server code: %s\n", nt_errstr(status)));
*tkey = NULL;
return status;
}
gensec_want_feature(k->gensec, GENSEC_FEATURE_SIGN);
status = gensec_start_mech_by_oid(k->gensec, GENSEC_OID_SPNEGO);
if (!NT_STATUS_IS_OK(status)) {
DEBUG(1, ("Failed to start GENSEC server code: %s\n",
nt_errstr(status)));
*tkey = NULL;
return status;
}
if (store->tkeys[store->next_idx] != NULL) {
TALLOC_FREE(store->tkeys[store->next_idx]);
}
store->tkeys[store->next_idx] = k;
(store->next_idx)++;
store->next_idx %= store->size;
*tkey = k;
return NT_STATUS_OK;
}
static NTSTATUS accept_gss_ticket(TALLOC_CTX *mem_ctx,
struct dns_server *dns,
struct dns_server_tkey *tkey,
const DATA_BLOB *key,
DATA_BLOB *reply,
uint16_t *dns_auth_error)
{
NTSTATUS status;
status = gensec_update_ev(tkey->gensec, mem_ctx, dns->task->event_ctx,
*key, reply);
if (NT_STATUS_EQUAL(NT_STATUS_MORE_PROCESSING_REQUIRED, status)) {
*dns_auth_error = DNS_RCODE_OK;
return status;
}
if (NT_STATUS_IS_OK(status)) {
status = gensec_session_info(tkey->gensec, tkey, &tkey->session_info);
if (!NT_STATUS_IS_OK(status)) {
*dns_auth_error = DNS_RCODE_BADKEY;
return status;
}
*dns_auth_error = DNS_RCODE_OK;
}
return status;
}
static WERROR handle_tkey(struct dns_server *dns,
TALLOC_CTX *mem_ctx,
const struct dns_name_packet *in,
struct dns_request_state *state,
struct dns_res_rec **answers,
uint16_t *ancount)
{
struct dns_res_rec *in_tkey = NULL;
struct dns_res_rec *ret_tkey;
uint16_t i;
for (i = 0; i < in->arcount; i++) {
if (in->additional[i].rr_type == DNS_QTYPE_TKEY) {
in_tkey = &in->additional[i];
break;
}
}
/* If this is a TKEY query, it should have a TKEY RR.
* Behaviour is not really specified in RFC 2930 or RFC 3645, but
* FORMAT_ERROR seems to be what BIND uses .*/
if (in_tkey == NULL) {
return DNS_ERR(FORMAT_ERROR);
}
ret_tkey = talloc_zero(mem_ctx, struct dns_res_rec);
if (ret_tkey == NULL) {
return WERR_NOMEM;
}
ret_tkey->name = talloc_strdup(ret_tkey, in_tkey->name);
if (ret_tkey->name == NULL) {
return WERR_NOMEM;
}
ret_tkey->rr_type = DNS_QTYPE_TKEY;
ret_tkey->rr_class = DNS_QCLASS_ANY;
ret_tkey->length = UINT16_MAX;
ret_tkey->rdata.tkey_record.algorithm = talloc_strdup(ret_tkey,
in_tkey->rdata.tkey_record.algorithm);
if (ret_tkey->rdata.tkey_record.algorithm == NULL) {
return WERR_NOMEM;
}
ret_tkey->rdata.tkey_record.inception = in_tkey->rdata.tkey_record.inception;
ret_tkey->rdata.tkey_record.expiration = in_tkey->rdata.tkey_record.expiration;
ret_tkey->rdata.tkey_record.mode = in_tkey->rdata.tkey_record.mode;
switch (in_tkey->rdata.tkey_record.mode) {
case DNS_TKEY_MODE_DH:
/* FIXME: According to RFC 2930, we MUST support this, but we don't.
* Still, claim it's a bad key instead of a bad mode */
ret_tkey->rdata.tkey_record.error = DNS_RCODE_BADKEY;
break;
case DNS_TKEY_MODE_GSSAPI: {
NTSTATUS status;
struct dns_server_tkey *tkey;
DATA_BLOB key;
DATA_BLOB reply;
tkey = dns_find_tkey(dns->tkeys, in->questions[0].name);
if (tkey != NULL && tkey->complete) {
/* TODO: check if the key is still valid */
DEBUG(1, ("Rejecting tkey negotiation for already established key\n"));
ret_tkey->rdata.tkey_record.error = DNS_RCODE_BADNAME;
break;
}
if (tkey == NULL) {
status = create_tkey(dns, in->questions[0].name,
in_tkey->rdata.tkey_record.algorithm,
&tkey);
if (!NT_STATUS_IS_OK(status)) {
ret_tkey->rdata.tkey_record.error = DNS_RCODE_BADKEY;
return ntstatus_to_werror(status);
}
}
key.data = in_tkey->rdata.tkey_record.key_data;
key.length = in_tkey->rdata.tkey_record.key_size;
status = accept_gss_ticket(ret_tkey, dns, tkey, &key, &reply,
&ret_tkey->rdata.tkey_record.error);
if (NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
DEBUG(1, ("More processing required\n"));
ret_tkey->rdata.tkey_record.error = DNS_RCODE_BADKEY;
} else if (NT_STATUS_IS_OK(status)) {
DEBUG(1, ("Tkey handshake completed\n"));
ret_tkey->rdata.tkey_record.key_size = reply.length;
ret_tkey->rdata.tkey_record.key_data = talloc_memdup(ret_tkey,
reply.data,
reply.length);
state->sign = true;
state->key_name = talloc_strdup(state->mem_ctx, tkey->name);
if (state->key_name == NULL) {
return WERR_NOMEM;
}
} else {
DEBUG(1, ("GSS key negotiation returned %s\n", nt_errstr(status)));
ret_tkey->rdata.tkey_record.error = DNS_RCODE_BADKEY;
}
break;
}
case DNS_TKEY_MODE_DELETE:
/* TODO: implement me */
DEBUG(1, ("Should delete tkey here\n"));
ret_tkey->rdata.tkey_record.error = DNS_RCODE_OK;
break;
case DNS_TKEY_MODE_NULL:
case DNS_TKEY_MODE_SERVER:
case DNS_TKEY_MODE_CLIENT:
case DNS_TKEY_MODE_LAST:
/* We don't have to implement these, return a mode error */
ret_tkey->rdata.tkey_record.error = DNS_RCODE_BADMODE;
break;
default:
DEBUG(1, ("Unsupported TKEY mode %d\n",
in_tkey->rdata.tkey_record.mode));
}
*answers = ret_tkey;
*ancount = 1;
return WERR_OK;
}
struct dns_server_process_query_state {
struct tevent_context *ev;
struct dns_server *dns;
struct dns_name_question *question;
struct dns_res_rec *answers;
uint16_t ancount;
struct dns_res_rec *nsrecs;
uint16_t nscount;
struct dns_res_rec *additional;
uint16_t arcount;
struct forwarder_string *forwarders;
};
static void dns_server_process_query_got_auth(struct tevent_req *subreq);
static void dns_server_process_query_got_response(struct tevent_req *subreq);
struct tevent_req *dns_server_process_query_send(
TALLOC_CTX *mem_ctx, struct tevent_context *ev,
struct dns_server *dns, struct dns_request_state *req_state,
const struct dns_name_packet *in)
{
struct tevent_req *req, *subreq;
struct dns_server_process_query_state *state;
const char **forwarders = NULL;
unsigned int i;
req = tevent_req_create(mem_ctx, &state,
struct dns_server_process_query_state);
if (req == NULL) {
return NULL;
}
if (in->qdcount != 1) {
tevent_req_werror(req, DNS_ERR(FORMAT_ERROR));
return tevent_req_post(req, ev);
}
/* Windows returns NOT_IMPLEMENTED on this as well */
if (in->questions[0].question_class == DNS_QCLASS_NONE) {
tevent_req_werror(req, DNS_ERR(NOT_IMPLEMENTED));
return tevent_req_post(req, ev);
}
if (in->questions[0].question_type == DNS_QTYPE_TKEY) {
WERROR err;
err = handle_tkey(dns, state, in, req_state,
&state->answers, &state->ancount);
if (tevent_req_werror(req, err)) {
return tevent_req_post(req, ev);
}
tevent_req_done(req);
return tevent_req_post(req, ev);
}
state->dns = dns;
state->ev = ev;
state->question = &in->questions[0];
forwarders = lpcfg_dns_forwarder(dns->task->lp_ctx);
for (i = 0; forwarders != NULL && forwarders[i] != NULL; i++) {
struct forwarder_string *f = talloc_zero(state,
struct forwarder_string);
f->forwarder = forwarders[i];
DLIST_ADD_END(state->forwarders, f);
}
if (dns_authoritative_for_zone(dns, in->questions[0].name)) {
req_state->flags |= DNS_FLAG_AUTHORITATIVE;
/*
* Initialize the response arrays, so that we can use
* them as their own talloc contexts when doing the
* realloc
*/
state->answers = talloc_array(state, struct dns_res_rec, 0);
if (tevent_req_nomem(state->answers, req)) {
return tevent_req_post(req, ev);
}
state->nsrecs = talloc_array(state, struct dns_res_rec, 0);
if (tevent_req_nomem(state->nsrecs, req)) {
return tevent_req_post(req, ev);
}
subreq = handle_authoritative_send(
state, ev, dns, (forwarders == NULL ? NULL : forwarders[0]),
&in->questions[0], &state->answers, &state->nsrecs,
0); /* cname_depth */
if (tevent_req_nomem(subreq, req)) {
return tevent_req_post(req, ev);
}
tevent_req_set_callback(
subreq, dns_server_process_query_got_auth, req);
return req;
}
if ((req_state->flags & DNS_FLAG_RECURSION_DESIRED) &&
(req_state->flags & DNS_FLAG_RECURSION_AVAIL)) {
DEBUG(2, ("Not authoritative for '%s', forwarding\n",
in->questions[0].name));
subreq = ask_forwarder_send(state, ev, dns,
(forwarders == NULL ? NULL : forwarders[0]),
&in->questions[0]);
if (tevent_req_nomem(subreq, req)) {
return tevent_req_post(req, ev);
}
tevent_req_set_callback(
subreq, dns_server_process_query_got_response, req);
return req;
}
tevent_req_werror(req, DNS_ERR(NAME_ERROR));
return tevent_req_post(req, ev);
}
static void dns_server_process_query_got_response(struct tevent_req *subreq)
{
struct tevent_req *req = tevent_req_callback_data(
subreq, struct tevent_req);
struct dns_server_process_query_state *state = tevent_req_data(
req, struct dns_server_process_query_state);
WERROR werr;
werr = ask_forwarder_recv(subreq, state,
&state->answers, &state->ancount,
&state->nsrecs, &state->nscount,
&state->additional, &state->arcount);
TALLOC_FREE(subreq);
/* If you get an error, attempt a different forwarder */
if (!W_ERROR_IS_OK(werr)) {
if (state->forwarders != NULL) {
DLIST_REMOVE(state->forwarders, state->forwarders);
}
/* If you have run out of forwarders, simply finish */
if (state->forwarders == NULL) {
tevent_req_werror(req, werr);
return;
}
DEBUG(5, ("DNS query returned %s, trying another forwarder.\n",
win_errstr(werr)));
subreq = ask_forwarder_send(state, state->ev, state->dns,
state->forwarders->forwarder,
state->question);
if (tevent_req_nomem(subreq, req)) {
return;
}
tevent_req_set_callback(subreq,
dns_server_process_query_got_response,
req);
return;
}
tevent_req_done(req);
}
static void dns_server_process_query_got_auth(struct tevent_req *subreq)
{
struct tevent_req *req = tevent_req_callback_data(
subreq, struct tevent_req);
struct dns_server_process_query_state *state = tevent_req_data(
req, struct dns_server_process_query_state);
WERROR werr;
werr = handle_authoritative_recv(subreq);
TALLOC_FREE(subreq);
/* If you get an error, attempt a different forwarder */
if (!W_ERROR_IS_OK(werr)) {
if (state->forwarders != NULL) {
DLIST_REMOVE(state->forwarders, state->forwarders);
}
/* If you have run out of forwarders, simply finish */
if (state->forwarders == NULL) {
tevent_req_werror(req, werr);
return;
}
DEBUG(5, ("Error: %s, trying a different forwarder.\n",
win_errstr(werr)));
subreq = handle_authoritative_send(state, state->ev, state->dns,
state->forwarders->forwarder,
state->question, &state->answers,
&state->nsrecs,
0); /* cname_depth */
if (tevent_req_nomem(subreq, req)) {
return;
}
tevent_req_set_callback(subreq,
dns_server_process_query_got_auth,
req);
return;
}
state->ancount = talloc_array_length(state->answers);
state->nscount = talloc_array_length(state->nsrecs);
state->arcount = talloc_array_length(state->additional);
tevent_req_done(req);
}
WERROR dns_server_process_query_recv(
struct tevent_req *req, TALLOC_CTX *mem_ctx,
struct dns_res_rec **answers, uint16_t *ancount,
struct dns_res_rec **nsrecs, uint16_t *nscount,
struct dns_res_rec **additional, uint16_t *arcount)
{
struct dns_server_process_query_state *state = tevent_req_data(
req, struct dns_server_process_query_state);
WERROR err = WERR_OK;
if (tevent_req_is_werror(req, &err)) {
if ((!W_ERROR_EQUAL(err, DNS_ERR(NAME_ERROR))) &&
(!W_ERROR_EQUAL(err, WERR_DNS_ERROR_NAME_DOES_NOT_EXIST))) {
return err;
}
}
*answers = talloc_move(mem_ctx, &state->answers);
*ancount = state->ancount;
*nsrecs = talloc_move(mem_ctx, &state->nsrecs);
*nscount = state->nscount;
*additional = talloc_move(mem_ctx, &state->additional);
*arcount = state->arcount;
return err;
}
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