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samba-mirror/source4/kdc/wdc-samba4.c
Stefan Metzmacher dceae1bb13 s4:kdc: use sdb_entry_to_hdb_entry() directly
We should avoid sdb_entry_ex, as it will be removed soon.

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
2022-03-24 09:19:33 +00:00

558 lines
14 KiB
C

/*
Unix SMB/CIFS implementation.
PAC Glue between Samba and the KDC
Copyright (C) Andrew Bartlett <abartlet@samba.org> 2005-2009
Copyright (C) Simo Sorce <idra@samba.org> 2010
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 "kdc/kdc-glue.h"
#include "kdc/db-glue.h"
#include "kdc/pac-glue.h"
#include "sdb.h"
#include "sdb_hdb.h"
#include "librpc/gen_ndr/auth.h"
#include <krb5_locl.h>
/*
* Given the right private pointer from hdb_samba4,
* get a PAC from the attached ldb messages.
*
* For PKINIT we also get pk_reply_key and can add PAC_CREDENTIAL_INFO.
*/
static krb5_error_code samba_wdc_get_pac(void *priv,
astgs_request_t r,
hdb_entry *client,
hdb_entry *server,
const krb5_keyblock *pk_reply_key,
uint64_t pac_attributes,
krb5_pac *pac)
{
krb5_context context = kdc_request_get_context((kdc_request_t)r);
TALLOC_CTX *mem_ctx;
DATA_BLOB *logon_blob = NULL;
DATA_BLOB *cred_ndr = NULL;
DATA_BLOB **cred_ndr_ptr = NULL;
DATA_BLOB _cred_blob = data_blob_null;
DATA_BLOB *cred_blob = NULL;
DATA_BLOB *upn_blob = NULL;
DATA_BLOB *pac_attrs_blob = NULL;
DATA_BLOB *requester_sid_blob = NULL;
krb5_error_code ret;
NTSTATUS nt_status;
struct samba_kdc_entry *skdc_entry =
talloc_get_type_abort(client->context,
struct samba_kdc_entry);
bool is_krbtgt;
mem_ctx = talloc_named(client->context, 0, "samba_get_pac context");
if (!mem_ctx) {
return ENOMEM;
}
if (pk_reply_key != NULL) {
cred_ndr_ptr = &cred_ndr;
}
is_krbtgt = krb5_principal_is_krbtgt(context, server->principal);
nt_status = samba_kdc_get_pac_blobs(mem_ctx, skdc_entry,
&logon_blob,
cred_ndr_ptr,
&upn_blob,
is_krbtgt ? &pac_attrs_blob : NULL,
pac_attributes,
is_krbtgt ? &requester_sid_blob : NULL);
if (!NT_STATUS_IS_OK(nt_status)) {
talloc_free(mem_ctx);
return EINVAL;
}
if (pk_reply_key != NULL && cred_ndr != NULL) {
ret = samba_kdc_encrypt_pac_credentials(context,
pk_reply_key,
cred_ndr,
mem_ctx,
&_cred_blob);
if (ret != 0) {
talloc_free(mem_ctx);
return ret;
}
cred_blob = &_cred_blob;
}
ret = krb5_pac_init(context, pac);
if (ret != 0) {
talloc_free(mem_ctx);
return ret;
}
ret = samba_make_krb5_pac(context, logon_blob, cred_blob,
upn_blob, pac_attrs_blob,
requester_sid_blob, NULL, *pac);
talloc_free(mem_ctx);
return ret;
}
static krb5_error_code samba_wdc_reget_pac2(krb5_context context,
const krb5_principal delegated_proxy_principal,
hdb_entry *client,
hdb_entry *server,
hdb_entry *krbtgt,
krb5_pac *pac,
krb5_cksumtype ctype)
{
struct samba_kdc_entry *client_skdc_entry = NULL;
struct samba_kdc_entry *server_skdc_entry =
talloc_get_type_abort(server->context, struct samba_kdc_entry);
struct samba_kdc_entry *krbtgt_skdc_entry =
talloc_get_type_abort(krbtgt->context, struct samba_kdc_entry);
TALLOC_CTX *mem_ctx = NULL;
krb5_pac new_pac = NULL;
krb5_error_code ret;
bool is_in_db = false;
bool is_untrusted = false;
uint32_t flags = 0;
mem_ctx = talloc_named(NULL, 0, "samba_kdc_reget_pac2 context");
if (mem_ctx == NULL) {
return ENOMEM;
}
if (client != NULL) {
client_skdc_entry = talloc_get_type_abort(client->context,
struct samba_kdc_entry);
}
/*
* If the krbtgt was generated by an RODC, and we are not that
* RODC, then we need to regenerate the PAC - we can't trust
* it, and confirm that the RODC was permitted to print this ticket
*
* Becasue of the samba_kdc_validate_pac_blob() step we can be
* sure that the record in 'client' matches the SID in the
* original PAC.
*/
ret = samba_krbtgt_is_in_db(krbtgt_skdc_entry, &is_in_db, &is_untrusted);
if (ret != 0) {
goto out;
}
if (delegated_proxy_principal != NULL) {
krb5_enctype etype;
Key *key = NULL;
if (!is_in_db) {
/*
* The RODC-issued PAC was signed by a KDC entry that we
* don't have a key for. The server signature is not
* trustworthy, since it could have been created by the
* server we got the ticket from. We must not proceed as
* otherwise the ticket signature is unchecked.
*/
ret = HDB_ERR_NOT_FOUND_HERE;
goto out;
}
/* Fetch the correct key depending on the checksum type. */
if (ctype == CKSUMTYPE_HMAC_MD5) {
etype = ENCTYPE_ARCFOUR_HMAC;
} else {
ret = krb5_cksumtype_to_enctype(context,
ctype,
&etype);
if (ret != 0) {
goto out;
}
}
ret = hdb_enctype2key(context, krbtgt, NULL, etype, &key);
if (ret != 0) {
goto out;
}
/* Check the KDC and ticket signatures. */
ret = krb5_pac_verify(context,
*pac,
0,
NULL,
NULL,
&key->key);
if (ret != 0) {
DEBUG(1, ("PAC KDC signature failed to verify\n"));
goto out;
}
flags |= SAMBA_KDC_FLAG_CONSTRAINED_DELEGATION;
}
if (is_untrusted) {
flags |= SAMBA_KDC_FLAG_KRBTGT_IS_UNTRUSTED;
}
if (is_in_db) {
flags |= SAMBA_KDC_FLAG_KRBTGT_IN_DB;
}
ret = krb5_pac_init(context, &new_pac);
if (ret != 0) {
new_pac = NULL;
goto out;
}
ret = samba_kdc_update_pac(mem_ctx,
context,
krbtgt_skdc_entry->kdc_db_ctx->samdb,
flags,
client_skdc_entry,
server->principal,
server_skdc_entry,
krbtgt_skdc_entry,
delegated_proxy_principal,
*pac,
new_pac);
if (ret != 0) {
krb5_pac_free(context, new_pac);
if (ret == ENODATA) {
krb5_pac_free(context, *pac);
*pac = NULL;
ret = 0;
}
goto out;
}
/* Replace the pac */
krb5_pac_free(context, *pac);
*pac = new_pac;
out:
talloc_free(mem_ctx);
return ret;
}
/* Resign (and reform, including possibly new groups) a PAC */
static krb5_error_code samba_wdc_reget_pac(void *priv, astgs_request_t r,
const krb5_principal client_principal,
const krb5_principal delegated_proxy_principal,
hdb_entry *client,
hdb_entry *server,
hdb_entry *krbtgt,
krb5_pac *pac)
{
krb5_context context = kdc_request_get_context((kdc_request_t)r);
krb5_kdc_configuration *config = kdc_request_get_config((kdc_request_t)r);
struct samba_kdc_entry *krbtgt_skdc_entry =
talloc_get_type_abort(krbtgt->context,
struct samba_kdc_entry);
krb5_error_code ret;
krb5_cksumtype ctype = CKSUMTYPE_NONE;
hdb_entry signing_krbtgt_hdb;
if (delegated_proxy_principal) {
uint16_t rodc_id;
unsigned int my_krbtgt_number;
/*
* We're using delegated_proxy_principal for the moment to
* indicate cases where the ticket was encrypted with the server
* key, and not a krbtgt key. This cannot be trusted, so we need
* to find a krbtgt key that signs the PAC in order to trust the
* ticket.
*
* The krbtgt passed in to this function refers to the krbtgt
* used to decrypt the ticket of the server requesting
* S4U2Proxy.
*
* When we implement service ticket renewal, we need to check
* the PAC, and this will need to be updated.
*/
ret = krb5_pac_get_kdc_checksum_info(context,
*pac,
&ctype,
&rodc_id);
if (ret != 0) {
DEBUG(1, ("Failed to get PAC checksum info\n"));
return ret;
}
/*
* We need to check the KDC and ticket signatures, fetching the
* correct key based on the enctype.
*/
my_krbtgt_number = krbtgt_skdc_entry->kdc_db_ctx->my_krbtgt_number;
if (my_krbtgt_number != 0) {
/*
* If we are an RODC, and we are not the KDC that signed
* the evidence ticket, then we need to proxy the
* request.
*/
if (rodc_id != my_krbtgt_number) {
return HDB_ERR_NOT_FOUND_HERE;
}
} else {
/*
* If we are a DC, the ticket may have been signed by a
* different KDC than the one that issued the header
* ticket.
*/
if (rodc_id != krbtgt->kvno >> 16) {
struct sdb_entry_ex signing_krbtgt_sdb;
/*
* If we didn't sign the ticket, then return an
* error.
*/
if (rodc_id != 0) {
return KRB5KRB_AP_ERR_MODIFIED;
}
/*
* Fetch our key from the database. To support
* key rollover, we're going to need to try
* multiple keys by trial and error. For now,
* krbtgt keys aren't assumed to change.
*/
ret = samba_kdc_fetch(context,
krbtgt_skdc_entry->kdc_db_ctx,
krbtgt->principal,
SDB_F_GET_KRBTGT | SDB_F_CANON,
0,
&signing_krbtgt_sdb);
if (ret != 0) {
return ret;
}
ret = sdb_entry_to_hdb_entry(context,
&signing_krbtgt_sdb.entry,
&signing_krbtgt_hdb);
sdb_free_entry(&signing_krbtgt_sdb);
if (ret != 0) {
return ret;
}
/*
* Replace the krbtgt entry with our own entry
* for further processing.
*/
krbtgt = &signing_krbtgt_hdb;
}
}
}
ret = samba_wdc_reget_pac2(context,
delegated_proxy_principal,
client,
server,
krbtgt,
pac,
ctype);
if (krbtgt == &signing_krbtgt_hdb) {
hdb_free_entry(context, config->db[0], &signing_krbtgt_hdb);
}
return ret;
}
static char *get_netbios_name(TALLOC_CTX *mem_ctx, HostAddresses *addrs)
{
char *nb_name = NULL;
size_t len;
unsigned int i;
for (i = 0; addrs && i < addrs->len; i++) {
if (addrs->val[i].addr_type != KRB5_ADDRESS_NETBIOS) {
continue;
}
len = MIN(addrs->val[i].address.length, 15);
nb_name = talloc_strndup(mem_ctx,
addrs->val[i].address.data, len);
if (nb_name) {
break;
}
}
if ((nb_name == NULL) || (nb_name[0] == '\0')) {
return NULL;
}
/* Strip space padding */
for (len = strlen(nb_name) - 1;
(len > 0) && (nb_name[len] == ' ');
--len) {
nb_name[len] = '\0';
}
return nb_name;
}
/* this function allocates 'data' using malloc.
* The caller is responsible for freeing it */
static void samba_kdc_build_edata_reply(NTSTATUS nt_status, krb5_data *e_data)
{
e_data->data = malloc(12);
if (e_data->data == NULL) {
e_data->length = 0;
e_data->data = NULL;
return;
}
e_data->length = 12;
SIVAL(e_data->data, 0, NT_STATUS_V(nt_status));
SIVAL(e_data->data, 4, 0);
SIVAL(e_data->data, 8, 1);
return;
}
static krb5_error_code samba_wdc_check_client_access(void *priv,
astgs_request_t r)
{
struct samba_kdc_entry *kdc_entry;
bool password_change;
char *workstation;
NTSTATUS nt_status;
kdc_entry = talloc_get_type(kdc_request_get_client(r)->context, struct samba_kdc_entry);
password_change = (kdc_request_get_server(r) && kdc_request_get_server(r)->flags.change_pw);
workstation = get_netbios_name((TALLOC_CTX *)kdc_request_get_client(r)->context,
kdc_request_get_req(r)->req_body.addresses);
nt_status = samba_kdc_check_client_access(kdc_entry,
kdc_request_get_cname((kdc_request_t)r),
workstation,
password_change);
if (!NT_STATUS_IS_OK(nt_status)) {
if (NT_STATUS_EQUAL(nt_status, NT_STATUS_NO_MEMORY)) {
return ENOMEM;
}
if (kdc_request_get_rep(r)->padata) {
int ret;
krb5_data kd;
samba_kdc_build_edata_reply(nt_status, &kd);
ret = krb5_padata_add(kdc_request_get_context((kdc_request_t)r), kdc_request_get_rep(r)->padata,
KRB5_PADATA_PW_SALT,
kd.data, kd.length);
if (ret != 0) {
/*
* So we do not leak the allocated
* memory on kd in the error case
*/
krb5_data_free(&kd);
}
}
return samba_kdc_map_policy_err(nt_status);
}
/* Now do the standard Heimdal check */
return KRB5_PLUGIN_NO_HANDLE;
}
/* this function allocates 'data' using malloc.
* The caller is responsible for freeing it */
static krb5_error_code samba_kdc_build_supported_etypes(uint32_t supported_etypes,
krb5_data *e_data)
{
e_data->data = malloc(4);
if (e_data->data == NULL) {
return ENOMEM;
}
e_data->length = 4;
PUSH_LE_U32(e_data->data, 0, supported_etypes);
return 0;
}
static krb5_error_code samba_wdc_finalize_reply(void *priv,
astgs_request_t r)
{
struct samba_kdc_entry *server_kdc_entry;
uint32_t supported_enctypes;
server_kdc_entry = talloc_get_type(kdc_request_get_server(r)->context, struct samba_kdc_entry);
/*
* If the canonicalize flag is set, add PA-SUPPORTED-ENCTYPES padata
* type to indicate what encryption types the server supports.
*/
supported_enctypes = server_kdc_entry->supported_enctypes;
if (kdc_request_get_req(r)->req_body.kdc_options.canonicalize && supported_enctypes != 0) {
krb5_error_code ret;
PA_DATA md;
ret = samba_kdc_build_supported_etypes(supported_enctypes, &md.padata_value);
if (ret != 0) {
return ret;
}
md.padata_type = KRB5_PADATA_SUPPORTED_ETYPES;
ret = kdc_request_add_encrypted_padata(r, &md);
if (ret != 0) {
/*
* So we do not leak the allocated
* memory on kd in the error case
*/
krb5_data_free(&md.padata_value);
}
}
return 0;
}
static krb5_error_code samba_wdc_plugin_init(krb5_context context, void **ptr)
{
*ptr = NULL;
return 0;
}
static void samba_wdc_plugin_fini(void *ptr)
{
return;
}
static krb5_error_code samba_wdc_referral_policy(void *priv,
astgs_request_t r)
{
return kdc_request_get_error_code((kdc_request_t)r);
}
struct krb5plugin_kdc_ftable kdc_plugin_table = {
.minor_version = KRB5_PLUGIN_KDC_VERSION_10,
.init = samba_wdc_plugin_init,
.fini = samba_wdc_plugin_fini,
.pac_verify = samba_wdc_reget_pac,
.client_access = samba_wdc_check_client_access,
.finalize_reply = samba_wdc_finalize_reply,
.pac_generate = samba_wdc_get_pac,
.referral_policy = samba_wdc_referral_policy,
};