diff options
Diffstat (limited to 'source4/kdc/db-glue.c')
| -rw-r--r-- | source4/kdc/db-glue.c | 3668 |
1 files changed, 3668 insertions, 0 deletions
diff --git a/source4/kdc/db-glue.c b/source4/kdc/db-glue.c new file mode 100644 index 0000000..83d5c90 --- /dev/null +++ b/source4/kdc/db-glue.c @@ -0,0 +1,3668 @@ +/* + Unix SMB/CIFS implementation. + + Database 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 "libcli/security/security.h" +#include "librpc/gen_ndr/ndr_security.h" +#include "auth/auth.h" +#include "auth/auth_sam.h" +#include "dsdb/samdb/samdb.h" +#include "dsdb/common/util.h" +#include "librpc/gen_ndr/ndr_drsblobs.h" +#include "param/param.h" +#include "param/secrets.h" +#include "../lib/crypto/md4.h" +#include "system/kerberos.h" +#include "auth/kerberos/kerberos.h" +#include "kdc/sdb.h" +#include "kdc/samba_kdc.h" +#include "kdc/db-glue.h" +#include "kdc/pac-glue.h" +#include "librpc/gen_ndr/ndr_irpc_c.h" +#include "lib/messaging/irpc.h" + +#undef strcasecmp +#undef strncasecmp + +#define SAMBA_KVNO_GET_KRBTGT(kvno) \ + ((uint16_t)(((uint32_t)kvno) >> 16)) + +#define SAMBA_KVNO_GET_VALUE(kvno) \ + ((uint16_t)(((uint32_t)kvno) & 0xFFFF)) + +#define SAMBA_KVNO_AND_KRBTGT(kvno, krbtgt) \ + ((krb5_kvno)((((uint32_t)kvno) & 0xFFFF) | \ + ((((uint32_t)krbtgt) << 16) & 0xFFFF0000))) + +enum trust_direction { + UNKNOWN = 0, + INBOUND = LSA_TRUST_DIRECTION_INBOUND, + OUTBOUND = LSA_TRUST_DIRECTION_OUTBOUND +}; + +static const char *trust_attrs[] = { + "securityIdentifier", + "flatName", + "trustPartner", + "trustAttributes", + "trustDirection", + "trustType", + "msDS-TrustForestTrustInfo", + "trustAuthIncoming", + "trustAuthOutgoing", + "whenCreated", + "msDS-SupportedEncryptionTypes", + NULL +}; + +/* + send a message to the drepl server telling it to initiate a + REPL_SECRET getncchanges extended op to fetch the users secrets + */ +static void auth_sam_trigger_repl_secret(TALLOC_CTX *mem_ctx, + struct imessaging_context *msg_ctx, + struct tevent_context *event_ctx, + struct ldb_dn *user_dn) +{ + struct dcerpc_binding_handle *irpc_handle; + struct drepl_trigger_repl_secret r; + struct tevent_req *req; + TALLOC_CTX *tmp_ctx; + + tmp_ctx = talloc_new(mem_ctx); + if (tmp_ctx == NULL) { + return; + } + + irpc_handle = irpc_binding_handle_by_name(tmp_ctx, msg_ctx, + "dreplsrv", + &ndr_table_irpc); + if (irpc_handle == NULL) { + DEBUG(1,(__location__ ": Unable to get binding handle for dreplsrv\n")); + TALLOC_FREE(tmp_ctx); + return; + } + + r.in.user_dn = ldb_dn_get_linearized(user_dn); + + /* + * This seem to rely on the current IRPC implementation, + * which delivers the message in the _send function. + * + * TODO: we need a ONE_WAY IRPC handle and register + * a callback and wait for it to be triggered! + */ + req = dcerpc_drepl_trigger_repl_secret_r_send(tmp_ctx, + event_ctx, + irpc_handle, + &r); + + /* we aren't interested in a reply */ + talloc_free(req); + TALLOC_FREE(tmp_ctx); +} + +static time_t ldb_msg_find_krb5time_ldap_time(struct ldb_message *msg, const char *attr, time_t default_val) +{ + const char *tmp; + const char *gentime; + struct tm tm; + + gentime = ldb_msg_find_attr_as_string(msg, attr, NULL); + if (!gentime) + return default_val; + + tmp = strptime(gentime, "%Y%m%d%H%M%SZ", &tm); + if (tmp == NULL) { + return default_val; + } + + return timegm(&tm); +} + +static struct SDBFlags uf2SDBFlags(krb5_context context, uint32_t userAccountControl, enum samba_kdc_ent_type ent_type) +{ + struct SDBFlags flags = int2SDBFlags(0); + + /* we don't allow kadmin deletes */ + flags.immutable = 1; + + /* mark the principal as invalid to start with */ + flags.invalid = 1; + + flags.renewable = 1; + + /* All accounts are servers, but this may be disabled again in the caller */ + flags.server = 1; + + /* Account types - clear the invalid bit if it turns out to be valid */ + if (userAccountControl & UF_NORMAL_ACCOUNT) { + if (ent_type == SAMBA_KDC_ENT_TYPE_CLIENT || ent_type == SAMBA_KDC_ENT_TYPE_ANY) { + flags.client = 1; + } + flags.invalid = 0; + } + + if (userAccountControl & UF_INTERDOMAIN_TRUST_ACCOUNT) { + if (ent_type == SAMBA_KDC_ENT_TYPE_CLIENT || ent_type == SAMBA_KDC_ENT_TYPE_ANY) { + flags.client = 1; + } + flags.invalid = 0; + } + if (userAccountControl & UF_WORKSTATION_TRUST_ACCOUNT) { + if (ent_type == SAMBA_KDC_ENT_TYPE_CLIENT || ent_type == SAMBA_KDC_ENT_TYPE_ANY) { + flags.client = 1; + } + flags.invalid = 0; + } + if (userAccountControl & UF_SERVER_TRUST_ACCOUNT) { + if (ent_type == SAMBA_KDC_ENT_TYPE_CLIENT || ent_type == SAMBA_KDC_ENT_TYPE_ANY) { + flags.client = 1; + } + flags.invalid = 0; + } + + /* Not permitted to act as a client if disabled */ + if (userAccountControl & UF_ACCOUNTDISABLE) { + flags.client = 0; + } + if (userAccountControl & UF_LOCKOUT) { + flags.locked_out = 1; + } +/* + if (userAccountControl & UF_PASSWORD_NOTREQD) { + flags.invalid = 1; + } +*/ +/* + UF_PASSWORD_CANT_CHANGE and UF_ENCRYPTED_TEXT_PASSWORD_ALLOWED are irrelevent +*/ + if (userAccountControl & UF_TEMP_DUPLICATE_ACCOUNT) { + flags.invalid = 1; + } + +/* UF_DONT_EXPIRE_PASSWD and UF_USE_DES_KEY_ONLY handled in samba_kdc_message2entry() */ + +/* + if (userAccountControl & UF_MNS_LOGON_ACCOUNT) { + flags.invalid = 1; + } +*/ + if (userAccountControl & UF_SMARTCARD_REQUIRED) { + flags.require_hwauth = 1; + } + if (userAccountControl & UF_TRUSTED_FOR_DELEGATION) { + flags.ok_as_delegate = 1; + } + if (userAccountControl & UF_TRUSTED_TO_AUTHENTICATE_FOR_DELEGATION) { + /* + * this is confusing... + * + * UF_TRUSTED_FOR_DELEGATION + * => ok_as_delegate + * + * and + * + * UF_TRUSTED_TO_AUTHENTICATE_FOR_DELEGATION + * => trusted_for_delegation + */ + flags.trusted_for_delegation = 1; + } + if (!(userAccountControl & UF_NOT_DELEGATED)) { + flags.forwardable = 1; + flags.proxiable = 1; + } + + if (userAccountControl & UF_DONT_REQUIRE_PREAUTH) { + flags.require_preauth = 0; + } else { + flags.require_preauth = 1; + } + + if (userAccountControl & UF_NO_AUTH_DATA_REQUIRED) { + flags.no_auth_data_reqd = 1; + } + + return flags; +} + +static int samba_kdc_entry_destructor(struct samba_kdc_entry *p) +{ + if (p->db_entry != NULL) { + /* + * A sdb_entry still has a reference + */ + return -1; + } + + if (p->kdc_entry != NULL) { + /* + * hdb_entry or krb5_db_entry still + * have a reference... + */ + return -1; + } + + return 0; +} + +/* + * Sort keys in descending order of strength. + * + * Explanaton from Greg Hudson: + * + * To encrypt tickets only the first returned key is used by the MIT KDC. The + * other keys just communicate support for session key enctypes, and aren't + * really used. The encryption key for the ticket enc part doesn't have + * to be of a type requested by the client. The session key enctype is chosen + * based on the client preference order, limited by the set of enctypes present + * in the server keys (unless the string attribute is set on the server + * principal overriding that set). + */ + +static int sdb_key_strength_priority(krb5_enctype etype) +{ + static const krb5_enctype etype_list[] = { + ENCTYPE_AES256_CTS_HMAC_SHA1_96, + ENCTYPE_AES128_CTS_HMAC_SHA1_96, + ENCTYPE_DES3_CBC_SHA1, + ENCTYPE_ARCFOUR_HMAC, + ENCTYPE_DES_CBC_MD5, + ENCTYPE_DES_CBC_MD4, + ENCTYPE_DES_CBC_CRC, + ENCTYPE_NULL + }; + int i; + + for (i = 0; i < ARRAY_SIZE(etype_list); i++) { + if (etype == etype_list[i]) { + break; + } + } + + return ARRAY_SIZE(etype_list) - i; +} + +static int sdb_key_strength_cmp(const struct sdb_key *k1, const struct sdb_key *k2) +{ + int p1 = sdb_key_strength_priority(KRB5_KEY_TYPE(&k1->key)); + int p2 = sdb_key_strength_priority(KRB5_KEY_TYPE(&k2->key)); + + if (p1 == p2) { + return 0; + } + + if (p1 > p2) { + /* + * Higher priority comes first + */ + return -1; + } else { + return 1; + } +} + +static void samba_kdc_sort_keys(struct sdb_keys *keys) +{ + if (keys == NULL) { + return; + } + + TYPESAFE_QSORT(keys->val, keys->len, sdb_key_strength_cmp); +} + +int samba_kdc_set_fixed_keys(krb5_context context, + const struct ldb_val *secretbuffer, + uint32_t supported_enctypes, + struct sdb_keys *keys) +{ + uint16_t allocated_keys = 0; + int ret; + + allocated_keys = 3; + keys->len = 0; + keys->val = calloc(allocated_keys, sizeof(struct sdb_key)); + if (keys->val == NULL) { + memset(secretbuffer->data, 0, secretbuffer->length); + ret = ENOMEM; + goto out; + } + + if (supported_enctypes & ENC_HMAC_SHA1_96_AES256) { + struct sdb_key key = {}; + + ret = smb_krb5_keyblock_init_contents(context, + ENCTYPE_AES256_CTS_HMAC_SHA1_96, + secretbuffer->data, + MIN(secretbuffer->length, 32), + &key.key); + if (ret) { + memset(secretbuffer->data, 0, secretbuffer->length); + goto out; + } + + keys->val[keys->len] = key; + keys->len++; + } + + if (supported_enctypes & ENC_HMAC_SHA1_96_AES128) { + struct sdb_key key = {}; + + ret = smb_krb5_keyblock_init_contents(context, + ENCTYPE_AES128_CTS_HMAC_SHA1_96, + secretbuffer->data, + MIN(secretbuffer->length, 16), + &key.key); + if (ret) { + memset(secretbuffer->data, 0, secretbuffer->length); + goto out; + } + + keys->val[keys->len] = key; + keys->len++; + } + + if (supported_enctypes & ENC_RC4_HMAC_MD5) { + struct sdb_key key = {}; + + ret = smb_krb5_keyblock_init_contents(context, + ENCTYPE_ARCFOUR_HMAC, + secretbuffer->data, + MIN(secretbuffer->length, 16), + &key.key); + if (ret) { + memset(secretbuffer->data, 0, secretbuffer->length); + goto out; + } + + keys->val[keys->len] = key; + keys->len++; + } + ret = 0; +out: + return ret; +} + + +static int samba_kdc_set_random_keys(krb5_context context, + uint32_t supported_enctypes, + struct sdb_keys *keys) +{ + struct ldb_val secret_val; + uint8_t secretbuffer[32]; + + /* + * Fake keys until we have a better way to reject + * non-pkinit requests. + * + * We just need to indicate which encryption types are + * supported. + */ + generate_secret_buffer(secretbuffer, sizeof(secretbuffer)); + + secret_val = data_blob_const(secretbuffer, + sizeof(secretbuffer)); + return samba_kdc_set_fixed_keys(context, + &secret_val, + supported_enctypes, + keys); +} + +struct samba_kdc_user_keys { + struct sdb_keys *skeys; + uint32_t kvno; + uint32_t *returned_kvno; + uint32_t supported_enctypes; + uint32_t *available_enctypes; + const struct samr_Password *nthash; + const char *salt_string; + uint16_t num_pkeys; + const struct package_PrimaryKerberosKey4 *pkeys; +}; + +static krb5_error_code samba_kdc_fill_user_keys(krb5_context context, + struct samba_kdc_user_keys *p) +{ + /* + * Make sure we'll never reveal DES keys + */ + uint32_t supported_enctypes = p->supported_enctypes &= ~(ENC_CRC32 | ENC_RSA_MD5); + uint32_t _available_enctypes = 0; + uint32_t *available_enctypes = p->available_enctypes; + uint32_t _returned_kvno = 0; + uint32_t *returned_kvno = p->returned_kvno; + uint32_t num_pkeys = p->num_pkeys; + uint32_t allocated_keys = num_pkeys; + uint32_t i; + int ret; + + if (available_enctypes == NULL) { + available_enctypes = &_available_enctypes; + } + + *available_enctypes = 0; + + if (returned_kvno == NULL) { + returned_kvno = &_returned_kvno; + } + + *returned_kvno = p->kvno; + + if (p->nthash != NULL) { + allocated_keys += 1; + } + + allocated_keys = MAX(1, allocated_keys); + + /* allocate space to decode into */ + p->skeys->len = 0; + p->skeys->val = calloc(allocated_keys, sizeof(struct sdb_key)); + if (p->skeys->val == NULL) { + return ENOMEM; + } + + for (i=0; i < num_pkeys; i++) { + struct sdb_key key = {}; + uint32_t enctype_bit; + + if (p->pkeys[i].value == NULL) { + continue; + } + + enctype_bit = kerberos_enctype_to_bitmap(p->pkeys[i].keytype); + if (!(enctype_bit & supported_enctypes)) { + continue; + } + + if (p->salt_string != NULL) { + DATA_BLOB salt; + + salt = data_blob_string_const(p->salt_string); + + key.salt = calloc(1, sizeof(*key.salt)); + if (key.salt == NULL) { + ret = ENOMEM; + goto fail; + } + + key.salt->type = KRB5_PW_SALT; + + ret = smb_krb5_copy_data_contents(&key.salt->salt, + salt.data, + salt.length); + if (ret) { + ZERO_STRUCTP(key.salt); + sdb_key_free(&key); + goto fail; + } + } + + ret = smb_krb5_keyblock_init_contents(context, + p->pkeys[i].keytype, + p->pkeys[i].value->data, + p->pkeys[i].value->length, + &key.key); + if (ret == 0) { + p->skeys->val[p->skeys->len++] = key; + *available_enctypes |= enctype_bit; + continue; + } + ZERO_STRUCT(key.key); + sdb_key_free(&key); + if (ret == KRB5_PROG_ETYPE_NOSUPP) { + DEBUG(2,("Unsupported keytype ignored - type %u\n", + p->pkeys[i].keytype)); + ret = 0; + continue; + } + + goto fail; + } + + if (p->nthash != NULL && (supported_enctypes & ENC_RC4_HMAC_MD5)) { + struct sdb_key key = {}; + + ret = smb_krb5_keyblock_init_contents(context, + ENCTYPE_ARCFOUR_HMAC, + p->nthash->hash, + sizeof(p->nthash->hash), + &key.key); + if (ret == 0) { + p->skeys->val[p->skeys->len++] = key; + + *available_enctypes |= ENC_RC4_HMAC_MD5; + } else if (ret == KRB5_PROG_ETYPE_NOSUPP) { + DEBUG(2,("Unsupported keytype ignored - type %u\n", + ENCTYPE_ARCFOUR_HMAC)); + ret = 0; + } + if (ret != 0) { + goto fail; + } + } + + samba_kdc_sort_keys(p->skeys); + + return 0; +fail: + sdb_keys_free(p->skeys); + return ret; +} + +krb5_error_code samba_kdc_message2entry_keys(krb5_context context, + TALLOC_CTX *mem_ctx, + const struct ldb_message *msg, + bool is_krbtgt, + bool is_rodc, + uint32_t userAccountControl, + enum samba_kdc_ent_type ent_type, + unsigned flags, + krb5_kvno requested_kvno, + struct sdb_entry *entry, + const uint32_t supported_enctypes_in, + uint32_t *supported_enctypes_out) +{ + krb5_error_code ret = 0; + enum ndr_err_code ndr_err; + struct samr_Password *hash; + unsigned int num_ntPwdHistory = 0; + struct samr_Password *ntPwdHistory = NULL; + struct samr_Password *old_hash = NULL; + struct samr_Password *older_hash = NULL; + const struct ldb_val *sc_val; + struct supplementalCredentialsBlob scb; + struct supplementalCredentialsPackage *scpk = NULL; + struct package_PrimaryKerberosBlob _pkb; + struct package_PrimaryKerberosCtr4 *pkb4 = NULL; + int krbtgt_number = 0; + uint32_t current_kvno; + uint32_t old_kvno = 0; + uint32_t older_kvno = 0; + uint32_t returned_kvno = 0; + uint16_t i; + struct samba_kdc_user_keys keys = { .num_pkeys = 0, }; + struct samba_kdc_user_keys old_keys = { .num_pkeys = 0, }; + struct samba_kdc_user_keys older_keys = { .num_pkeys = 0, }; + uint32_t available_enctypes = 0; + uint32_t supported_enctypes = supported_enctypes_in; + + *supported_enctypes_out = 0; + + /* Is this the krbtgt or a RODC krbtgt */ + if (is_rodc) { + krbtgt_number = ldb_msg_find_attr_as_int(msg, "msDS-SecondaryKrbTgtNumber", -1); + + if (krbtgt_number == -1) { + return EINVAL; + } + if (krbtgt_number == 0) { + return EINVAL; + } + } + + if ((ent_type == SAMBA_KDC_ENT_TYPE_CLIENT) + && (userAccountControl & UF_SMARTCARD_REQUIRED)) { + ret = samba_kdc_set_random_keys(context, + supported_enctypes, + &entry->keys); + + *supported_enctypes_out = supported_enctypes & ENC_ALL_TYPES; + + goto out; + } + + current_kvno = ldb_msg_find_attr_as_int(msg, "msDS-KeyVersionNumber", 0); + if (current_kvno > 1) { + old_kvno = current_kvno - 1; + } + if (current_kvno > 2) { + older_kvno = current_kvno - 2; + } + if (is_krbtgt) { + /* + * Even for the main krbtgt account + * we have to strictly split the kvno into + * two 16-bit parts and the upper 16-bit + * need to be all zero, even if + * the msDS-KeyVersionNumber has a value + * larger than 65535. + * + * See https://bugzilla.samba.org/show_bug.cgi?id=14951 + */ + current_kvno = SAMBA_KVNO_GET_VALUE(current_kvno); + old_kvno = SAMBA_KVNO_GET_VALUE(old_kvno); + older_kvno = SAMBA_KVNO_GET_VALUE(older_kvno); + requested_kvno = SAMBA_KVNO_GET_VALUE(requested_kvno); + } + + /* Get keys from the db */ + + hash = samdb_result_hash(mem_ctx, msg, "unicodePwd"); + num_ntPwdHistory = samdb_result_hashes(mem_ctx, msg, + "ntPwdHistory", + &ntPwdHistory); + if (num_ntPwdHistory > 1) { + old_hash = &ntPwdHistory[1]; + } + if (num_ntPwdHistory > 2) { + older_hash = &ntPwdHistory[1]; + } + sc_val = ldb_msg_find_ldb_val(msg, "supplementalCredentials"); + + /* supplementalCredentials if present */ + if (sc_val) { + ndr_err = ndr_pull_struct_blob_all(sc_val, mem_ctx, &scb, + (ndr_pull_flags_fn_t)ndr_pull_supplementalCredentialsBlob); + if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) { + dump_data(0, sc_val->data, sc_val->length); + ret = EINVAL; + goto out; + } + + if (scb.sub.signature != SUPPLEMENTAL_CREDENTIALS_SIGNATURE) { + if (scb.sub.num_packages != 0) { + NDR_PRINT_DEBUG(supplementalCredentialsBlob, &scb); + ret = EINVAL; + goto out; + } + } + + for (i=0; i < scb.sub.num_packages; i++) { + if (strcmp("Primary:Kerberos-Newer-Keys", scb.sub.packages[i].name) == 0) { + scpk = &scb.sub.packages[i]; + if (!scpk->data || !scpk->data[0]) { + scpk = NULL; + continue; + } + break; + } + } + } + /* + * Primary:Kerberos-Newer-Keys element + * of supplementalCredentials + * + * The legacy Primary:Kerberos only contains + * single DES keys, which are completely ignored + * now. + */ + if (scpk) { + DATA_BLOB blob; + + blob = strhex_to_data_blob(mem_ctx, scpk->data); + if (!blob.data) { + ret = ENOMEM; + goto out; + } + + /* we cannot use ndr_pull_struct_blob_all() here, as w2k and w2k3 add padding bytes */ + ndr_err = ndr_pull_struct_blob(&blob, mem_ctx, &_pkb, + (ndr_pull_flags_fn_t)ndr_pull_package_PrimaryKerberosBlob); + if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) { + ret = EINVAL; + krb5_set_error_message(context, ret, "samba_kdc_message2entry_keys: could not parse package_PrimaryKerberosBlob"); + krb5_warnx(context, "samba_kdc_message2entry_keys: could not parse package_PrimaryKerberosBlob"); + goto out; + } + + if (_pkb.version != 4) { + ret = EINVAL; + krb5_set_error_message(context, ret, "samba_kdc_message2entry_keys: Primary:Kerberos-Newer-Keys not version 4"); + krb5_warnx(context, "samba_kdc_message2entry_keys: Primary:Kerberos-Newer-Keys not version 4"); + goto out; + } + + pkb4 = &_pkb.ctr.ctr4; + } + + keys = (struct samba_kdc_user_keys) { + .kvno = current_kvno, + .supported_enctypes = supported_enctypes, + .nthash = hash, + .salt_string = pkb4 != NULL ? pkb4->salt.string : NULL, + .num_pkeys = pkb4 != NULL ? pkb4->num_keys : 0, + .pkeys = pkb4 != NULL ? pkb4->keys : NULL, + }; + + old_keys = (struct samba_kdc_user_keys) { + .kvno = old_kvno, + .supported_enctypes = supported_enctypes, + .nthash = old_hash, + .salt_string = pkb4 != NULL ? pkb4->salt.string : NULL, + .num_pkeys = pkb4 != NULL ? pkb4->num_old_keys : 0, + .pkeys = pkb4 != NULL ? pkb4->old_keys : NULL, + }; + older_keys = (struct samba_kdc_user_keys) { + .kvno = older_kvno, + .supported_enctypes = supported_enctypes, + .nthash = older_hash, + .salt_string = pkb4 != NULL ? pkb4->salt.string : NULL, + .num_pkeys = pkb4 != NULL ? pkb4->num_older_keys : 0, + .pkeys = pkb4 != NULL ? pkb4->older_keys : NULL, + }; + + if (flags & SDB_F_KVNO_SPECIFIED) { + if (requested_kvno == keys.kvno) { + /* + * The current kvno was requested, + * so we return it. + */ + keys.skeys = &entry->keys; + keys.available_enctypes = &available_enctypes; + keys.returned_kvno = &returned_kvno; + } else if (requested_kvno == 0) { + /* + * don't return any keys + */ + } else if (requested_kvno == old_keys.kvno) { + /* + * return the old keys as default keys + * with the requested kvno. + */ + old_keys.skeys = &entry->keys; + old_keys.available_enctypes = &available_enctypes; + old_keys.returned_kvno = &returned_kvno; + } else if (requested_kvno == older_keys.kvno) { + /* + * return the older keys as default keys + * with the requested kvno. + */ + older_keys.skeys = &entry->keys; + older_keys.available_enctypes = &available_enctypes; + older_keys.returned_kvno = &returned_kvno; + } else { + /* + * don't return any keys + */ + } + } else { + bool include_history = false; + + if ((flags & SDB_F_GET_CLIENT) && (flags & SDB_F_FOR_AS_REQ)) { + include_history = true; + } else if (flags & SDB_F_ADMIN_DATA) { + include_history = true; + } + + keys.skeys = &entry->keys; + keys.available_enctypes = &available_enctypes; + keys.returned_kvno = &returned_kvno; + + if (include_history && old_keys.kvno != 0) { + old_keys.skeys = &entry->old_keys; + } + if (include_history && older_keys.kvno != 0) { + older_keys.skeys = &entry->older_keys; + } + } + + if (keys.skeys != NULL) { + ret = samba_kdc_fill_user_keys(context, &keys); + if (ret != 0) { + goto out; + } + } + + if (old_keys.skeys != NULL) { + ret = samba_kdc_fill_user_keys(context, &old_keys); + if (ret != 0) { + goto out; + } + } + + if (older_keys.skeys != NULL) { + ret = samba_kdc_fill_user_keys(context, &older_keys); + if (ret != 0) { + goto out; + } + } + + *supported_enctypes_out |= available_enctypes; + + if (is_krbtgt) { + /* + * Even for the main krbtgt account + * we have to strictly split the kvno into + * two 16-bit parts and the upper 16-bit + * need to be all zero, even if + * the msDS-KeyVersionNumber has a value + * larger than 65535. + * + * See https://bugzilla.samba.org/show_bug.cgi?id=14951 + */ + returned_kvno = SAMBA_KVNO_AND_KRBTGT(returned_kvno, krbtgt_number); + } + entry->kvno = returned_kvno; + +out: + return ret; +} + +static int principal_comp_strcmp_int(krb5_context context, + krb5_const_principal principal, + unsigned int component, + const char *string, + bool do_strcasecmp) +{ + const char *p; + +#if defined(HAVE_KRB5_PRINCIPAL_GET_COMP_STRING) + p = krb5_principal_get_comp_string(context, principal, component); + if (p == NULL) { + return -1; + } + if (do_strcasecmp) { + return strcasecmp(p, string); + } else { + return strcmp(p, string); + } +#else + size_t len; + krb5_data *d; + if (component >= krb5_princ_size(context, principal)) { + return -1; + } + + d = krb5_princ_component(context, principal, component); + if (d == NULL) { + return -1; + } + + p = d->data; + + len = strlen(string); + + /* + * We explicitly return -1 or 1. Subtracting of the two lengths might + * give the wrong result if the result overflows or loses data when + * narrowed to int. + */ + if (d->length < len) { + return -1; + } else if (d->length > len) { + return 1; + } + + if (do_strcasecmp) { + return strncasecmp(p, string, len); + } else { + return memcmp(p, string, len); + } +#endif +} + +static int principal_comp_strcasecmp(krb5_context context, + krb5_const_principal principal, + unsigned int component, + const char *string) +{ + return principal_comp_strcmp_int(context, principal, + component, string, true); +} + +static int principal_comp_strcmp(krb5_context context, + krb5_const_principal principal, + unsigned int component, + const char *string) +{ + return principal_comp_strcmp_int(context, principal, + component, string, false); +} + +static bool is_kadmin_changepw(krb5_context context, + krb5_const_principal principal) +{ + return krb5_princ_size(context, principal) == 2 && + (principal_comp_strcmp(context, principal, 0, "kadmin") == 0) && + (principal_comp_strcmp(context, principal, 1, "changepw") == 0); +} + +static krb5_error_code samba_kdc_get_entry_principal( + krb5_context context, + struct samba_kdc_db_context *kdc_db_ctx, + const char *samAccountName, + enum samba_kdc_ent_type ent_type, + unsigned flags, + bool is_kadmin_changepw, + krb5_const_principal in_princ, + krb5_principal *out_princ) +{ + struct loadparm_context *lp_ctx = kdc_db_ctx->lp_ctx; + krb5_error_code code = 0; + bool canon = flags & (SDB_F_CANON|SDB_F_FORCE_CANON); + + /* + * If we are set to canonicalize, we get back the fixed UPPER + * case realm, and the real username (ie matching LDAP + * samAccountName) + * + * Otherwise, if we are set to enterprise, we + * get back the whole principal as-sent + * + * Finally, if we are not set to canonicalize, we get back the + * fixed UPPER case realm, but the as-sent username + */ + + /* + * We need to ensure that the kadmin/changepw principal isn't able to + * issue krbtgt tickets, even if canonicalization is turned on. + */ + if (!is_kadmin_changepw) { + if (ent_type == SAMBA_KDC_ENT_TYPE_KRBTGT && canon) { + /* + * When requested to do so, ensure that the + * both realm values in the principal are set + * to the upper case, canonical realm + */ + code = smb_krb5_make_principal(context, + out_princ, + lpcfg_realm(lp_ctx), + "krbtgt", + lpcfg_realm(lp_ctx), + NULL); + if (code != 0) { + return code; + } + smb_krb5_principal_set_type(context, + *out_princ, + KRB5_NT_SRV_INST); + + return 0; + } + + if ((canon && flags & (SDB_F_FORCE_CANON|SDB_F_FOR_AS_REQ)) || + (ent_type == SAMBA_KDC_ENT_TYPE_ANY && in_princ == NULL)) { + /* + * SDB_F_CANON maps from the canonicalize flag in the + * packet, and has a different meaning between AS-REQ + * and TGS-REQ. We only change the principal in the + * AS-REQ case. + * + * The SDB_F_FORCE_CANON if for new MIT KDC code that + * wants the canonical name in all lookups, and takes + * care to canonicalize only when appropriate. + */ + code = smb_krb5_make_principal(context, + out_princ, + lpcfg_realm(lp_ctx), + samAccountName, + NULL); + return code; + } + } + + /* + * For a krbtgt entry, this appears to be required regardless of the + * canonicalize flag from the client. + */ + code = krb5_copy_principal(context, in_princ, out_princ); + if (code != 0) { + return code; + } + + /* + * While we have copied the client principal, tests show that Win2k3 + * returns the 'corrected' realm, not the client-specified realm. This + * code attempts to replace the client principal's realm with the one + * we determine from our records + */ + code = smb_krb5_principal_set_realm(context, + *out_princ, + lpcfg_realm(lp_ctx)); + + return code; +} + +/* + * Construct an hdb_entry from a directory entry. + */ +static krb5_error_code samba_kdc_message2entry(krb5_context context, + struct samba_kdc_db_context *kdc_db_ctx, + TALLOC_CTX *mem_ctx, + krb5_const_principal principal, + enum samba_kdc_ent_type ent_type, + unsigned flags, + krb5_kvno kvno, + struct ldb_dn *realm_dn, + struct ldb_message *msg, + struct sdb_entry *entry) +{ + struct loadparm_context *lp_ctx = kdc_db_ctx->lp_ctx; + uint32_t userAccountControl; + uint32_t msDS_User_Account_Control_Computed; + krb5_error_code ret = 0; + krb5_boolean is_computer = FALSE; + struct samba_kdc_entry *p; + NTTIME acct_expiry; + NTSTATUS status; + bool protected_user = false; + uint32_t rid; + bool is_krbtgt = false; + bool is_rodc = false; + bool force_rc4 = lpcfg_kdc_force_enable_rc4_weak_session_keys(lp_ctx); + struct ldb_message_element *objectclasses; + struct ldb_val computer_val = data_blob_string_const("computer"); + uint32_t config_default_supported_enctypes = lpcfg_kdc_default_domain_supported_enctypes(lp_ctx); + uint32_t default_supported_enctypes = + config_default_supported_enctypes != 0 ? + config_default_supported_enctypes : + ENC_RC4_HMAC_MD5 | ENC_HMAC_SHA1_96_AES256_SK; + uint32_t supported_enctypes + = ldb_msg_find_attr_as_uint(msg, + "msDS-SupportedEncryptionTypes", + default_supported_enctypes); + uint32_t pa_supported_enctypes; + uint32_t supported_session_etypes; + uint32_t available_enctypes = 0; + /* + * also lagacy enctypes are announced, + * but effectively restricted by kdc_enctypes + */ + uint32_t domain_enctypes = ENC_RC4_HMAC_MD5 | ENC_RSA_MD5 | ENC_CRC32; + uint32_t config_kdc_enctypes = lpcfg_kdc_supported_enctypes(lp_ctx); + uint32_t kdc_enctypes = + config_kdc_enctypes != 0 ? + config_kdc_enctypes : + ENC_ALL_TYPES; + const char *samAccountName = ldb_msg_find_attr_as_string(msg, "samAccountName", NULL); + + ZERO_STRUCTP(entry); + + if (supported_enctypes == 0) { + supported_enctypes = default_supported_enctypes; + } + + if (dsdb_functional_level(kdc_db_ctx->samdb) >= DS_DOMAIN_FUNCTION_2008) { + domain_enctypes |= ENC_HMAC_SHA1_96_AES128 | ENC_HMAC_SHA1_96_AES256; + } + + if (ldb_msg_find_element(msg, "msDS-SecondaryKrbTgtNumber")) { + is_rodc = true; + } + + if (!samAccountName) { + ret = ENOENT; + krb5_set_error_message(context, ret, "samba_kdc_message2entry: no samAccountName present"); + goto out; + } + + objectclasses = ldb_msg_find_element(msg, "objectClass"); + + if (objectclasses && ldb_msg_find_val(objectclasses, &computer_val)) { + is_computer = TRUE; + } + + p = talloc_zero(mem_ctx, struct samba_kdc_entry); + if (!p) { + ret = ENOMEM; + goto out; + } + + p->is_rodc = is_rodc; + p->kdc_db_ctx = kdc_db_ctx; + p->realm_dn = talloc_reference(p, realm_dn); + if (!p->realm_dn) { + ret = ENOMEM; + goto out; + } + + talloc_set_destructor(p, samba_kdc_entry_destructor); + + entry->skdc_entry = p; + + userAccountControl = ldb_msg_find_attr_as_uint(msg, "userAccountControl", 0); + + msDS_User_Account_Control_Computed + = ldb_msg_find_attr_as_uint(msg, + "msDS-User-Account-Control-Computed", + UF_ACCOUNTDISABLE); + + /* + * This brings in the lockout flag, block the account if not + * found. We need the weird UF_ACCOUNTDISABLE check because + * we do not want to fail open if the value is not returned, + * but 0 is a valid value (all OK) + */ + if (msDS_User_Account_Control_Computed == UF_ACCOUNTDISABLE) { + ret = EINVAL; + krb5_set_error_message(context, ret, "samba_kdc_message2entry: " + "no msDS-User-Account-Control-Computed present"); + goto out; + } else { + userAccountControl |= msDS_User_Account_Control_Computed; + } + + if (ent_type == SAMBA_KDC_ENT_TYPE_KRBTGT) { + p->is_krbtgt = true; + } + + /* First try and figure out the flags based on the userAccountControl */ + entry->flags = uf2SDBFlags(context, userAccountControl, ent_type); + + /* + * Take control of the returned principal here, rather than + * allowing the Heimdal code to do it as we have specific + * behaviour around the forced realm to honour + */ + entry->flags.force_canonicalize = true; + + /* Windows 2008 seems to enforce this (very sensible) rule by + * default - don't allow offline attacks on a user's password + * by asking for a ticket to them as a service (encrypted with + * their probably patheticly insecure password) */ + + if (entry->flags.server + && lpcfg_parm_bool(lp_ctx, NULL, "kdc", "require spn for service", true)) { + if (!is_computer && !ldb_msg_find_attr_as_string(msg, "servicePrincipalName", NULL)) { + entry->flags.server = 0; + } + } + + /* + * We restrict a 3-part SPN ending in my domain/realm to full + * domain controllers. + * + * This avoids any cases where (eg) a demoted DC still has + * these more restricted SPNs. + */ + if (krb5_princ_size(context, principal) > 2) { + char *third_part + = smb_krb5_principal_get_comp_string(mem_ctx, + context, + principal, + 2); + bool is_our_realm = + lpcfg_is_my_domain_or_realm(lp_ctx, + third_part); + bool is_dc = userAccountControl & + (UF_SERVER_TRUST_ACCOUNT | UF_PARTIAL_SECRETS_ACCOUNT); + if (is_our_realm && !is_dc) { + entry->flags.server = 0; + } + } + /* + * To give the correct type of error to the client, we must + * not just return the entry without .server set, we must + * pretend the principal does not exist. Otherwise we may + * return ERR_POLICY instead of + * KRB5KDC_ERR_S_PRINCIPAL_UNKNOWN + */ + if (ent_type == SAMBA_KDC_ENT_TYPE_SERVER && entry->flags.server == 0) { + ret = SDB_ERR_NOENTRY; + krb5_set_error_message(context, ret, "samba_kdc_message2entry: no servicePrincipalName present for this server, refusing with no-such-entry"); + goto out; + } + if (flags & SDB_F_ADMIN_DATA) { + /* These (created_by, modified_by) parts of the entry are not relevant for Samba4's use + * of the Heimdal KDC. They are stored in a the traditional + * DB for audit purposes, and still form part of the structure + * we must return */ + + /* use 'whenCreated' */ + entry->created_by.time = ldb_msg_find_krb5time_ldap_time(msg, "whenCreated", 0); + /* use 'kadmin' for now (needed by mit_samba) */ + + ret = smb_krb5_make_principal(context, + &entry->created_by.principal, + lpcfg_realm(lp_ctx), "kadmin", NULL); + if (ret) { + krb5_clear_error_message(context); + goto out; + } + + entry->modified_by = (struct sdb_event *) malloc(sizeof(struct sdb_event)); + if (entry->modified_by == NULL) { + ret = ENOMEM; + krb5_set_error_message(context, ret, "malloc: out of memory"); + goto out; + } + + /* use 'whenChanged' */ + entry->modified_by->time = ldb_msg_find_krb5time_ldap_time(msg, "whenChanged", 0); + /* use 'kadmin' for now (needed by mit_samba) */ + ret = smb_krb5_make_principal(context, + &entry->modified_by->principal, + lpcfg_realm(lp_ctx), "kadmin", NULL); + if (ret) { + krb5_clear_error_message(context); + goto out; + } + } + + + /* The lack of password controls etc applies to krbtgt by + * virtue of being that particular RID */ + status = dom_sid_split_rid(NULL, samdb_result_dom_sid(mem_ctx, msg, "objectSid"), NULL, &rid); + + if (!NT_STATUS_IS_OK(status)) { + ret = EINVAL; + goto out; + } + + if (rid == DOMAIN_RID_KRBTGT) { + char *realm = NULL; + + entry->valid_end = NULL; + entry->pw_end = NULL; + + entry->flags.invalid = 0; + entry->flags.server = 1; + + realm = smb_krb5_principal_get_realm( + mem_ctx, context, principal); + if (realm == NULL) { + ret = ENOMEM; + goto out; + } + + /* Don't mark all requests for the krbtgt/realm as + * 'change password', as otherwise we could get into + * trouble, and not enforce the password expirty. + * Instead, only do it when request is for the kpasswd service */ + if (ent_type == SAMBA_KDC_ENT_TYPE_SERVER && + is_kadmin_changepw(context, principal) && + lpcfg_is_my_domain_or_realm(lp_ctx, realm)) { + entry->flags.change_pw = 1; + } + + TALLOC_FREE(realm); + + entry->flags.client = 0; + entry->flags.forwardable = 1; + entry->flags.ok_as_delegate = 1; + } else if (is_rodc) { + /* The RODC krbtgt account is like the main krbtgt, + * but it does not have a changepw or kadmin + * service */ + + entry->valid_end = NULL; + entry->pw_end = NULL; + + /* Also don't allow the RODC krbtgt to be a client (it should not be needed) */ + entry->flags.client = 0; + entry->flags.invalid = 0; + entry->flags.server = 1; + + entry->flags.client = 0; + entry->flags.forwardable = 1; + entry->flags.ok_as_delegate = 0; + } else if (entry->flags.server && ent_type == SAMBA_KDC_ENT_TYPE_SERVER) { + /* The account/password expiry only applies when the account is used as a + * client (ie password login), not when used as a server */ + + /* Make very well sure we don't use this for a client, + * it could bypass the password restrictions */ + entry->flags.client = 0; + + entry->valid_end = NULL; + entry->pw_end = NULL; + + } else { + NTTIME must_change_time + = samdb_result_nttime(msg, + "msDS-UserPasswordExpiryTimeComputed", + 0); + if (must_change_time == 0x7FFFFFFFFFFFFFFFULL) { + entry->pw_end = NULL; + } else { + entry->pw_end = malloc(sizeof(*entry->pw_end)); + if (entry->pw_end == NULL) { + ret = ENOMEM; + goto out; + } + *entry->pw_end = nt_time_to_unix(must_change_time); + } + + acct_expiry = samdb_result_account_expires(msg); + if (acct_expiry == 0x7FFFFFFFFFFFFFFFULL) { + entry->valid_end = NULL; + } else { + entry->valid_end = malloc(sizeof(*entry->valid_end)); + if (entry->valid_end == NULL) { + ret = ENOMEM; + goto out; + } + *entry->valid_end = nt_time_to_unix(acct_expiry); + } + } + + ret = samba_kdc_get_entry_principal(context, + kdc_db_ctx, + samAccountName, + ent_type, + flags, + entry->flags.change_pw, + principal, + &entry->principal); + if (ret != 0) { + krb5_clear_error_message(context); + goto out; + } + + entry->valid_start = NULL; + + entry->max_life = malloc(sizeof(*entry->max_life)); + if (entry->max_life == NULL) { + ret = ENOMEM; + goto out; + } + + if (ent_type == SAMBA_KDC_ENT_TYPE_SERVER) { + *entry->max_life = kdc_db_ctx->policy.svc_tkt_lifetime; + } else if (ent_type == SAMBA_KDC_ENT_TYPE_KRBTGT || ent_type == SAMBA_KDC_ENT_TYPE_CLIENT) { + *entry->max_life = kdc_db_ctx->policy.usr_tkt_lifetime; + } else { + *entry->max_life = MIN(kdc_db_ctx->policy.svc_tkt_lifetime, + kdc_db_ctx->policy.usr_tkt_lifetime); + } + + if (entry->flags.change_pw) { + /* Limit lifetime of kpasswd tickets to two minutes or less. */ + *entry->max_life = MIN(*entry->max_life, CHANGEPW_LIFETIME); + } + + entry->max_renew = malloc(sizeof(*entry->max_renew)); + if (entry->max_renew == NULL) { + ret = ENOMEM; + goto out; + } + + *entry->max_renew = kdc_db_ctx->policy.renewal_lifetime; + + if (ent_type == SAMBA_KDC_ENT_TYPE_CLIENT && (flags & SDB_F_FOR_AS_REQ)) { + int result; + struct auth_user_info_dc *user_info_dc = NULL; + /* + * These protections only apply to clients, so servers in the + * Protected Users group may still have service tickets to them + * encrypted with RC4. For accounts looked up as servers, note + * that 'msg' does not contain the 'memberOf' attribute for + * determining whether the account is a member of Protected + * Users. + * + * Additionally, Microsoft advises that accounts for services + * and computers should never be members of Protected Users, or + * they may fail to authenticate. + */ + status = samba_kdc_get_user_info_from_db(p, msg, &user_info_dc); + if (!NT_STATUS_IS_OK(status)) { + ret = EINVAL; + goto out; + } + + result = dsdb_is_protected_user(kdc_db_ctx->samdb, + user_info_dc->sids, + user_info_dc->num_sids); + if (result == -1) { + ret = EINVAL; + goto out; + } + + protected_user = result; + + if (protected_user) { + *entry->max_life = MIN(*entry->max_life, 4 * 60 * 60); + *entry->max_renew = MIN(*entry->max_renew, 4 * 60 * 60); + + entry->flags.forwardable = 0; + entry->flags.proxiable = 0; + } + } + + if (rid == DOMAIN_RID_KRBTGT || is_rodc) { + bool enable_fast; + + is_krbtgt = true; + + /* + * KDCs (and KDCs on RODCs) + * ignore msDS-SupportedEncryptionTypes completely + * but support all supported enctypes by the domain. + */ + supported_enctypes = domain_enctypes; + + enable_fast = lpcfg_kdc_enable_fast(kdc_db_ctx->lp_ctx); + if (enable_fast) { + supported_enctypes |= ENC_FAST_SUPPORTED; + } + } else if (userAccountControl & (UF_PARTIAL_SECRETS_ACCOUNT|UF_SERVER_TRUST_ACCOUNT)) { + /* + * DCs and RODCs computer accounts take + * msDS-SupportedEncryptionTypes unmodified, but + * force all enctypes supported by the domain. + */ + supported_enctypes |= domain_enctypes; + + } else if (ent_type == SAMBA_KDC_ENT_TYPE_CLIENT || + (ent_type == SAMBA_KDC_ENT_TYPE_ANY)) { + /* + * for AS-REQ the client chooses the enc types it + * supports, and this will vary between computers a + * user logs in from. Therefore, so that we accept any + * of the client's keys for decrypting padata, + * supported_enctypes should not restrict etype usage. + * + * likewise for 'any' return as much as is supported, + * to export into a keytab. + */ + supported_enctypes |= ENC_ALL_TYPES; + } + + /* If UF_USE_DES_KEY_ONLY has been set, then don't allow use of the newer enc types */ + if (userAccountControl & UF_USE_DES_KEY_ONLY) { + supported_enctypes &= ~ENC_ALL_TYPES; + } + + if (protected_user) { + supported_enctypes &= ~ENC_RC4_HMAC_MD5; + } + + pa_supported_enctypes = supported_enctypes; + supported_session_etypes = supported_enctypes; + if (supported_session_etypes & ENC_HMAC_SHA1_96_AES256_SK) { + supported_session_etypes |= ENC_HMAC_SHA1_96_AES256; + supported_session_etypes |= ENC_HMAC_SHA1_96_AES128; + } + if (force_rc4) { + supported_session_etypes |= ENC_RC4_HMAC_MD5; + } + /* + * now that we remembered what to announce in pa_supported_enctypes + * and normalized ENC_HMAC_SHA1_96_AES256_SK, we restrict the + * rest to the enc types the local kdc supports. + */ + supported_enctypes &= kdc_enctypes; + supported_session_etypes &= kdc_enctypes; + + /* Get keys from the db */ + ret = samba_kdc_message2entry_keys(context, p, msg, + is_krbtgt, is_rodc, + userAccountControl, + ent_type, flags, kvno, entry, + supported_enctypes, + &available_enctypes); + if (ret) { + /* Could be bogus data in the entry, or out of memory */ + goto out; + } + + /* + * If we only have a nthash stored, + * but a better session key would be + * available, we fallback to fetching the + * RC4_HMAC_MD5, which implicitly also + * would allow an RC4_HMAC_MD5 session key. + * But only if the kdc actually supports + * RC4_HMAC_MD5. + */ + if (available_enctypes == 0 && + (supported_enctypes & ENC_RC4_HMAC_MD5) == 0 && + (supported_enctypes & ~ENC_RC4_HMAC_MD5) != 0 && + (kdc_enctypes & ENC_RC4_HMAC_MD5) != 0) + { + supported_enctypes = ENC_RC4_HMAC_MD5; + ret = samba_kdc_message2entry_keys(context, p, msg, + is_krbtgt, is_rodc, + userAccountControl, + ent_type, flags, kvno, entry, + supported_enctypes, + &available_enctypes); + if (ret) { + /* Could be bogus data in the entry, or out of memory */ + goto out; + } + } + + /* + * We need to support all session keys enctypes for + * all keys we provide + */ + supported_session_etypes |= available_enctypes; + + ret = sdb_entry_set_etypes(entry); + if (ret) { + goto out; + } + + if (entry->flags.server) { + bool add_aes256 = + supported_session_etypes & KERB_ENCTYPE_AES256_CTS_HMAC_SHA1_96; + bool add_aes128 = + supported_session_etypes & KERB_ENCTYPE_AES128_CTS_HMAC_SHA1_96; + bool add_rc4 = + supported_session_etypes & ENC_RC4_HMAC_MD5; + ret = sdb_entry_set_session_etypes(entry, + add_aes256, + add_aes128, + add_rc4); + if (ret) { + goto out; + } + } + + if (entry->keys.len != 0) { + /* + * FIXME: Currently limited to Heimdal so as not to + * break MIT KDCs, for which no fix is available. + */ +#ifdef SAMBA4_USES_HEIMDAL + if (is_krbtgt) { + /* + * The krbtgt account, having no reason to + * issue tickets encrypted in weaker keys, + * shall only make available its strongest + * key. All weaker keys are stripped out. This + * makes it impossible for an RC4-encrypted + * TGT to be accepted when AES KDC keys exist. + * + * This controls the ticket key and so the PAC + * signature algorithms indirectly, preventing + * a weak KDC checksum from being accepted + * when we verify the signatures for an + * S4U2Proxy evidence ticket. As such, this is + * indispensable for addressing + * CVE-2022-37966. + * + * Being strict here also provides protection + * against possible future attacks on weak + * keys. + */ + entry->keys.len = 1; + if (entry->etypes != NULL) { + entry->etypes->len = 1; + } + entry->old_keys.len = MIN(entry->old_keys.len, 1); + entry->older_keys.len = MIN(entry->older_keys.len, 1); + } +#endif + } else if (kdc_db_ctx->rodc) { + /* + * We are on an RODC, but don't have keys for this + * account. Signal this to the caller + */ + auth_sam_trigger_repl_secret(kdc_db_ctx, + kdc_db_ctx->msg_ctx, + kdc_db_ctx->ev_ctx, + msg->dn); + return SDB_ERR_NOT_FOUND_HERE; + } else { + /* + * oh, no password. Apparently (comment in + * hdb-ldap.c) this violates the ASN.1, but this + * allows an entry with no keys (yet). + */ + } + + p->msg = talloc_steal(p, msg); + p->supported_enctypes = pa_supported_enctypes; + +out: + if (ret != 0) { + /* This doesn't free ent itself, that is for the eventual caller to do */ + sdb_entry_free(entry); + } else { + talloc_steal(kdc_db_ctx, p); + } + + return ret; +} + +/* + * Construct an hdb_entry from a directory entry. + * The kvno is what the remote client asked for + */ +static krb5_error_code samba_kdc_trust_message2entry(krb5_context context, + struct samba_kdc_db_context *kdc_db_ctx, + TALLOC_CTX *mem_ctx, + enum trust_direction direction, + struct ldb_dn *realm_dn, + unsigned flags, + uint32_t kvno, + struct ldb_message *msg, + struct sdb_entry *entry) +{ + struct loadparm_context *lp_ctx = kdc_db_ctx->lp_ctx; + const char *our_realm = lpcfg_realm(lp_ctx); + char *partner_realm = NULL; + const char *realm = NULL; + const char *krbtgt_realm = NULL; + DATA_BLOB password_utf16 = data_blob_null; + DATA_BLOB password_utf8 = data_blob_null; + struct samr_Password _password_hash; + const struct samr_Password *password_hash = NULL; + const struct ldb_val *password_val; + struct trustAuthInOutBlob password_blob; + struct samba_kdc_entry *p; + bool use_previous = false; + uint32_t current_kvno; + uint32_t previous_kvno; + uint32_t num_keys = 0; + enum ndr_err_code ndr_err; + int ret; + unsigned int i; + struct AuthenticationInformationArray *auth_array; + struct timeval tv; + NTTIME an_hour_ago; + uint32_t *auth_kvno; + bool preferr_current = false; + bool force_rc4 = lpcfg_kdc_force_enable_rc4_weak_session_keys(lp_ctx); + uint32_t supported_enctypes = ENC_RC4_HMAC_MD5; + uint32_t pa_supported_enctypes; + uint32_t supported_session_etypes; + uint32_t config_kdc_enctypes = lpcfg_kdc_supported_enctypes(lp_ctx); + uint32_t kdc_enctypes = + config_kdc_enctypes != 0 ? + config_kdc_enctypes : + ENC_ALL_TYPES; + struct lsa_TrustDomainInfoInfoEx *tdo = NULL; + NTSTATUS status; + + ZERO_STRUCTP(entry); + + if (dsdb_functional_level(kdc_db_ctx->samdb) >= DS_DOMAIN_FUNCTION_2008) { + /* If not told otherwise, Windows now assumes that trusts support AES. */ + supported_enctypes = ldb_msg_find_attr_as_uint(msg, + "msDS-SupportedEncryptionTypes", + ENC_HMAC_SHA1_96_AES256); + } + + pa_supported_enctypes = supported_enctypes; + supported_session_etypes = supported_enctypes; + if (supported_session_etypes & ENC_HMAC_SHA1_96_AES256_SK) { + supported_session_etypes |= ENC_HMAC_SHA1_96_AES256; + supported_session_etypes |= ENC_HMAC_SHA1_96_AES128; + } + if (force_rc4) { + supported_session_etypes |= ENC_RC4_HMAC_MD5; + } + /* + * now that we remembered what to announce in pa_supported_enctypes + * and normalized ENC_HMAC_SHA1_96_AES256_SK, we restrict the + * rest to the enc types the local kdc supports. + */ + supported_enctypes &= kdc_enctypes; + supported_session_etypes &= kdc_enctypes; + + status = dsdb_trust_parse_tdo_info(mem_ctx, msg, &tdo); + if (!NT_STATUS_IS_OK(status)) { + krb5_clear_error_message(context); + ret = ENOMEM; + goto out; + } + + if (!(tdo->trust_direction & direction)) { + krb5_clear_error_message(context); + ret = SDB_ERR_NOENTRY; + goto out; + } + + if (tdo->trust_type != LSA_TRUST_TYPE_UPLEVEL) { + /* + * Only UPLEVEL domains support kerberos here, + * as we don't support LSA_TRUST_TYPE_MIT. + */ + krb5_clear_error_message(context); + ret = SDB_ERR_NOENTRY; + goto out; + } + + if (tdo->trust_attributes & LSA_TRUST_ATTRIBUTE_CROSS_ORGANIZATION) { + /* + * We don't support selective authentication yet. + */ + krb5_clear_error_message(context); + ret = SDB_ERR_NOENTRY; + goto out; + } + + if (tdo->domain_name.string == NULL) { + krb5_clear_error_message(context); + ret = SDB_ERR_NOENTRY; + goto out; + } + partner_realm = strupper_talloc(mem_ctx, tdo->domain_name.string); + if (partner_realm == NULL) { + krb5_clear_error_message(context); + ret = ENOMEM; + goto out; + } + + if (direction == INBOUND) { + realm = our_realm; + krbtgt_realm = partner_realm; + + password_val = ldb_msg_find_ldb_val(msg, "trustAuthIncoming"); + } else { /* OUTBOUND */ + realm = partner_realm; + krbtgt_realm = our_realm; + + password_val = ldb_msg_find_ldb_val(msg, "trustAuthOutgoing"); + } + + if (password_val == NULL) { + krb5_clear_error_message(context); + ret = SDB_ERR_NOENTRY; + goto out; + } + + ndr_err = ndr_pull_struct_blob(password_val, mem_ctx, &password_blob, + (ndr_pull_flags_fn_t)ndr_pull_trustAuthInOutBlob); + if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) { + krb5_clear_error_message(context); + ret = EINVAL; + goto out; + } + + p = talloc_zero(mem_ctx, struct samba_kdc_entry); + if (!p) { + ret = ENOMEM; + goto out; + } + + p->is_trust = true; + p->kdc_db_ctx = kdc_db_ctx; + p->realm_dn = realm_dn; + p->supported_enctypes = pa_supported_enctypes; + + talloc_set_destructor(p, samba_kdc_entry_destructor); + + entry->skdc_entry = p; + + /* use 'whenCreated' */ + entry->created_by.time = ldb_msg_find_krb5time_ldap_time(msg, "whenCreated", 0); + /* use 'kadmin' for now (needed by mit_samba) */ + ret = smb_krb5_make_principal(context, + &entry->created_by.principal, + realm, "kadmin", NULL); + if (ret) { + krb5_clear_error_message(context); + goto out; + } + + /* + * We always need to generate the canonicalized principal + * with the values of our database. + */ + ret = smb_krb5_make_principal(context, &entry->principal, realm, + "krbtgt", krbtgt_realm, NULL); + if (ret) { + krb5_clear_error_message(context); + goto out; + } + smb_krb5_principal_set_type(context, entry->principal, + KRB5_NT_SRV_INST); + + entry->valid_start = NULL; + + /* we need to work out if we are going to use the current or + * the previous password hash. + * We base this on the kvno the client passes in. If the kvno + * passed in is equal to the current kvno in our database then + * we use the current structure. If it is the current kvno-1, + * then we use the previous substrucure. + */ + + /* + * Windows preferrs the previous key for one hour. + */ + tv = timeval_current(); + if (tv.tv_sec > 3600) { + tv.tv_sec -= 3600; + } + an_hour_ago = timeval_to_nttime(&tv); + + /* first work out the current kvno */ + current_kvno = 0; + for (i=0; i < password_blob.count; i++) { + struct AuthenticationInformation *a = + &password_blob.current.array[i]; + + if (a->LastUpdateTime <= an_hour_ago) { + preferr_current = true; + } + + if (a->AuthType == TRUST_AUTH_TYPE_VERSION) { + current_kvno = a->AuthInfo.version.version; + } + } + if (current_kvno == 0) { + previous_kvno = 255; + } else { + previous_kvno = current_kvno - 1; + } + for (i=0; i < password_blob.count; i++) { + struct AuthenticationInformation *a = + &password_blob.previous.array[i]; + + if (a->AuthType == TRUST_AUTH_TYPE_VERSION) { + previous_kvno = a->AuthInfo.version.version; + } + } + + /* work out whether we will use the previous or current + password */ + if (password_blob.previous.count == 0) { + /* there is no previous password */ + use_previous = false; + } else if (!(flags & SDB_F_KVNO_SPECIFIED)) { + /* + * If not specified we use the lowest kvno + * for the first hour after an update. + */ + if (preferr_current) { + use_previous = false; + } else if (previous_kvno < current_kvno) { + use_previous = true; + } else { + use_previous = false; + } + } else if (kvno == current_kvno) { + /* + * Exact match ... + */ + use_previous = false; + } else if (kvno == previous_kvno) { + /* + * Exact match ... + */ + use_previous = true; + } else { + /* + * Fallback to the current one for anything else + */ + use_previous = false; + } + + if (use_previous) { + auth_array = &password_blob.previous; + auth_kvno = &previous_kvno; + } else { + auth_array = &password_blob.current; + auth_kvno = ¤t_kvno; + } + + /* use the kvno the client specified, if available */ + if (flags & SDB_F_KVNO_SPECIFIED) { + entry->kvno = kvno; + } else { + entry->kvno = *auth_kvno; + } + + for (i=0; i < auth_array->count; i++) { + if (auth_array->array[i].AuthType == TRUST_AUTH_TYPE_CLEAR) { + bool ok; + + password_utf16 = data_blob_const(auth_array->array[i].AuthInfo.clear.password, + auth_array->array[i].AuthInfo.clear.size); + if (password_utf16.length == 0) { + break; + } + + if (supported_enctypes & ENC_RC4_HMAC_MD5) { + mdfour(_password_hash.hash, password_utf16.data, password_utf16.length); + if (password_hash == NULL) { + num_keys += 1; + } + password_hash = &_password_hash; + } + + if (!(supported_enctypes & (ENC_HMAC_SHA1_96_AES128|ENC_HMAC_SHA1_96_AES256))) { + break; + } + + ok = convert_string_talloc(mem_ctx, + CH_UTF16MUNGED, CH_UTF8, + password_utf16.data, + password_utf16.length, + (void *)&password_utf8.data, + &password_utf8.length); + if (!ok) { + krb5_clear_error_message(context); + ret = ENOMEM; + goto out; + } + + if (supported_enctypes & ENC_HMAC_SHA1_96_AES128) { + num_keys += 1; + } + if (supported_enctypes & ENC_HMAC_SHA1_96_AES256) { + num_keys += 1; + } + break; + } else if (auth_array->array[i].AuthType == TRUST_AUTH_TYPE_NT4OWF) { + if (supported_enctypes & ENC_RC4_HMAC_MD5) { + password_hash = &auth_array->array[i].AuthInfo.nt4owf.password; + num_keys += 1; + } + } + } + + /* Must have found a cleartext or MD4 password */ + if (num_keys == 0) { + DEBUG(1,(__location__ ": no usable key found\n")); + krb5_clear_error_message(context); + ret = SDB_ERR_NOENTRY; + goto out; + } + + entry->keys.val = calloc(num_keys, sizeof(struct sdb_key)); + if (entry->keys.val == NULL) { + krb5_clear_error_message(context); + ret = ENOMEM; + goto out; + } + + if (password_utf8.length != 0) { + struct sdb_key key = {}; + krb5_const_principal salt_principal = entry->principal; + krb5_data salt; + krb5_data cleartext_data; + + cleartext_data.data = discard_const_p(char, password_utf8.data); + cleartext_data.length = password_utf8.length; + + ret = smb_krb5_get_pw_salt(context, + salt_principal, + &salt); + if (ret != 0) { + goto out; + } + + if (supported_enctypes & ENC_HMAC_SHA1_96_AES256) { + ret = smb_krb5_create_key_from_string(context, + salt_principal, + &salt, + &cleartext_data, + ENCTYPE_AES256_CTS_HMAC_SHA1_96, + &key.key); + if (ret != 0) { + smb_krb5_free_data_contents(context, &salt); + goto out; + } + + entry->keys.val[entry->keys.len] = key; + entry->keys.len++; + } + + if (supported_enctypes & ENC_HMAC_SHA1_96_AES128) { + ret = smb_krb5_create_key_from_string(context, + salt_principal, + &salt, + &cleartext_data, + ENCTYPE_AES128_CTS_HMAC_SHA1_96, + &key.key); + if (ret != 0) { + smb_krb5_free_data_contents(context, &salt); + goto out; + } + + entry->keys.val[entry->keys.len] = key; + entry->keys.len++; + } + + smb_krb5_free_data_contents(context, &salt); + } + + if (password_hash != NULL) { + struct sdb_key key = {}; + + ret = smb_krb5_keyblock_init_contents(context, + ENCTYPE_ARCFOUR_HMAC, + password_hash->hash, + sizeof(password_hash->hash), + &key.key); + if (ret != 0) { + goto out; + } + + entry->keys.val[entry->keys.len] = key; + entry->keys.len++; + } + + entry->flags = int2SDBFlags(0); + entry->flags.immutable = 1; + entry->flags.invalid = 0; + entry->flags.server = 1; + entry->flags.require_preauth = 1; + + entry->pw_end = NULL; + + entry->max_life = NULL; + + entry->max_renew = NULL; + + /* Match Windows behavior and allow forwardable flag in cross-realm. */ + entry->flags.forwardable = 1; + + samba_kdc_sort_keys(&entry->keys); + + ret = sdb_entry_set_etypes(entry); + if (ret) { + goto out; + } + + { + bool add_aes256 = + supported_session_etypes & KERB_ENCTYPE_AES256_CTS_HMAC_SHA1_96; + bool add_aes128 = + supported_session_etypes & KERB_ENCTYPE_AES128_CTS_HMAC_SHA1_96; + bool add_rc4 = + supported_session_etypes & ENC_RC4_HMAC_MD5; + ret = sdb_entry_set_session_etypes(entry, + add_aes256, + add_aes128, + add_rc4); + if (ret) { + goto out; + } + } + + p->msg = talloc_steal(p, msg); + +out: + TALLOC_FREE(partner_realm); + + if (ret != 0) { + /* This doesn't free ent itself, that is for the eventual caller to do */ + sdb_entry_free(entry); + } else { + talloc_steal(kdc_db_ctx, p); + } + + return ret; + +} + +static krb5_error_code samba_kdc_lookup_trust(krb5_context context, struct ldb_context *ldb_ctx, + TALLOC_CTX *mem_ctx, + const char *realm, + struct ldb_dn *realm_dn, + struct ldb_message **pmsg) +{ + NTSTATUS status; + const char * const *attrs = trust_attrs; + + status = dsdb_trust_search_tdo(ldb_ctx, realm, realm, + attrs, mem_ctx, pmsg); + if (NT_STATUS_IS_OK(status)) { + return 0; + } else if (NT_STATUS_EQUAL(status, NT_STATUS_OBJECT_NAME_NOT_FOUND)) { + return SDB_ERR_NOENTRY; + } else if (NT_STATUS_EQUAL(status, NT_STATUS_NO_MEMORY)) { + int ret = ENOMEM; + krb5_set_error_message(context, ret, "get_sam_result_trust: out of memory"); + return ret; + } else { + int ret = EINVAL; + krb5_set_error_message(context, ret, "get_sam_result_trust: %s", nt_errstr(status)); + return ret; + } +} + +static krb5_error_code samba_kdc_lookup_client(krb5_context context, + struct samba_kdc_db_context *kdc_db_ctx, + TALLOC_CTX *mem_ctx, + krb5_const_principal principal, + const char **attrs, + struct ldb_dn **realm_dn, + struct ldb_message **msg) +{ + NTSTATUS nt_status; + char *principal_string = NULL; + + if (smb_krb5_principal_get_type(context, principal) == KRB5_NT_ENTERPRISE_PRINCIPAL) { + principal_string = smb_krb5_principal_get_comp_string(mem_ctx, context, + principal, 0); + if (principal_string == NULL) { + return ENOMEM; + } + } else { + char *principal_string_m = NULL; + krb5_error_code ret; + + ret = krb5_unparse_name(context, principal, &principal_string_m); + if (ret != 0) { + return ret; + } + + principal_string = talloc_strdup(mem_ctx, principal_string_m); + SAFE_FREE(principal_string_m); + if (principal_string == NULL) { + return ENOMEM; + } + } + + nt_status = sam_get_results_principal(kdc_db_ctx->samdb, + mem_ctx, principal_string, attrs, + realm_dn, msg); + if (NT_STATUS_EQUAL(nt_status, NT_STATUS_NO_SUCH_USER)) { + krb5_principal fallback_principal = NULL; + unsigned int num_comp; + char *fallback_realm = NULL; + char *fallback_account = NULL; + krb5_error_code ret; + + ret = krb5_parse_name(context, principal_string, + &fallback_principal); + TALLOC_FREE(principal_string); + if (ret != 0) { + return ret; + } + + num_comp = krb5_princ_size(context, fallback_principal); + fallback_realm = smb_krb5_principal_get_realm( + mem_ctx, context, fallback_principal); + if (fallback_realm == NULL) { + krb5_free_principal(context, fallback_principal); + return ENOMEM; + } + + if (num_comp == 1) { + size_t len; + + fallback_account = smb_krb5_principal_get_comp_string(mem_ctx, + context, fallback_principal, 0); + if (fallback_account == NULL) { + krb5_free_principal(context, fallback_principal); + TALLOC_FREE(fallback_realm); + return ENOMEM; + } + + len = strlen(fallback_account); + if (len >= 2 && fallback_account[len - 1] == '$') { + TALLOC_FREE(fallback_account); + } + } + krb5_free_principal(context, fallback_principal); + fallback_principal = NULL; + + if (fallback_account != NULL) { + char *with_dollar; + + with_dollar = talloc_asprintf(mem_ctx, "%s$", + fallback_account); + if (with_dollar == NULL) { + TALLOC_FREE(fallback_realm); + return ENOMEM; + } + TALLOC_FREE(fallback_account); + + ret = smb_krb5_make_principal(context, + &fallback_principal, + fallback_realm, + with_dollar, NULL); + TALLOC_FREE(with_dollar); + if (ret != 0) { + TALLOC_FREE(fallback_realm); + return ret; + } + } + TALLOC_FREE(fallback_realm); + + if (fallback_principal != NULL) { + char *fallback_string = NULL; + + ret = krb5_unparse_name(context, + fallback_principal, + &fallback_string); + if (ret != 0) { + krb5_free_principal(context, fallback_principal); + return ret; + } + + nt_status = sam_get_results_principal(kdc_db_ctx->samdb, + mem_ctx, + fallback_string, + attrs, + realm_dn, msg); + SAFE_FREE(fallback_string); + } + krb5_free_principal(context, fallback_principal); + fallback_principal = NULL; + } + TALLOC_FREE(principal_string); + + if (NT_STATUS_EQUAL(nt_status, NT_STATUS_NO_SUCH_USER)) { + return SDB_ERR_NOENTRY; + } else if (NT_STATUS_EQUAL(nt_status, NT_STATUS_NO_MEMORY)) { + return ENOMEM; + } else if (!NT_STATUS_IS_OK(nt_status)) { + return EINVAL; + } + + return 0; +} + +static krb5_error_code samba_kdc_fetch_client(krb5_context context, + struct samba_kdc_db_context *kdc_db_ctx, + TALLOC_CTX *mem_ctx, + krb5_const_principal principal, + unsigned flags, + krb5_kvno kvno, + struct sdb_entry *entry) +{ + struct ldb_dn *realm_dn; + krb5_error_code ret; + struct ldb_message *msg = NULL; + + ret = samba_kdc_lookup_client(context, kdc_db_ctx, + mem_ctx, principal, user_attrs, + &realm_dn, &msg); + if (ret != 0) { + return ret; + } + + ret = samba_kdc_message2entry(context, kdc_db_ctx, mem_ctx, + principal, SAMBA_KDC_ENT_TYPE_CLIENT, + flags, kvno, + realm_dn, msg, entry); + return ret; +} + +static krb5_error_code samba_kdc_fetch_krbtgt(krb5_context context, + struct samba_kdc_db_context *kdc_db_ctx, + TALLOC_CTX *mem_ctx, + krb5_const_principal principal, + unsigned flags, + uint32_t kvno, + struct sdb_entry *entry) +{ + struct loadparm_context *lp_ctx = kdc_db_ctx->lp_ctx; + krb5_error_code ret; + struct ldb_message *msg = NULL; + struct ldb_dn *realm_dn = ldb_get_default_basedn(kdc_db_ctx->samdb); + char *realm_from_princ; + char *realm_princ_comp = smb_krb5_principal_get_comp_string(mem_ctx, context, principal, 1); + + realm_from_princ = smb_krb5_principal_get_realm( + mem_ctx, context, principal); + if (realm_from_princ == NULL) { + /* can't happen */ + return SDB_ERR_NOENTRY; + } + + if (krb5_princ_size(context, principal) != 2 + || (principal_comp_strcmp(context, principal, 0, KRB5_TGS_NAME) != 0)) { + /* Not a krbtgt */ + return SDB_ERR_NOENTRY; + } + + /* krbtgt case. Either us or a trusted realm */ + + if (lpcfg_is_my_domain_or_realm(lp_ctx, realm_from_princ) + && lpcfg_is_my_domain_or_realm(lp_ctx, realm_princ_comp)) { + /* us, or someone quite like us */ + /* Cludge, cludge cludge. If the realm part of krbtgt/realm, + * is in our db, then direct the caller at our primary + * krbtgt */ + + int lret; + unsigned int krbtgt_number; + /* w2k8r2 sometimes gives us a kvno of 255 for inter-domain + trust tickets. We don't yet know what this means, but we do + seem to need to treat it as unspecified */ + if (flags & SDB_F_KVNO_SPECIFIED) { + krbtgt_number = SAMBA_KVNO_GET_KRBTGT(kvno); + if (kdc_db_ctx->rodc) { + if (krbtgt_number != kdc_db_ctx->my_krbtgt_number) { + return SDB_ERR_NOT_FOUND_HERE; + } + } + } else { + krbtgt_number = kdc_db_ctx->my_krbtgt_number; + } + + if (krbtgt_number == kdc_db_ctx->my_krbtgt_number) { + lret = dsdb_search_one(kdc_db_ctx->samdb, mem_ctx, + &msg, kdc_db_ctx->krbtgt_dn, LDB_SCOPE_BASE, + krbtgt_attrs, DSDB_SEARCH_NO_GLOBAL_CATALOG, + "(objectClass=user)"); + } else { + /* We need to look up an RODC krbtgt (perhaps + * ours, if we are an RODC, perhaps another + * RODC if we are a read-write DC */ + lret = dsdb_search_one(kdc_db_ctx->samdb, mem_ctx, + &msg, realm_dn, LDB_SCOPE_SUBTREE, + krbtgt_attrs, + DSDB_SEARCH_SHOW_EXTENDED_DN | DSDB_SEARCH_NO_GLOBAL_CATALOG, + "(&(objectClass=user)(msDS-SecondaryKrbTgtNumber=%u))", (unsigned)(krbtgt_number)); + } + + if (lret == LDB_ERR_NO_SUCH_OBJECT) { + krb5_warnx(context, "samba_kdc_fetch: could not find KRBTGT number %u in DB!", + (unsigned)(krbtgt_number)); + krb5_set_error_message(context, SDB_ERR_NOENTRY, + "samba_kdc_fetch: could not find KRBTGT number %u in DB!", + (unsigned)(krbtgt_number)); + return SDB_ERR_NOENTRY; + } else if (lret != LDB_SUCCESS) { + krb5_warnx(context, "samba_kdc_fetch: could not find KRBTGT number %u in DB!", + (unsigned)(krbtgt_number)); + krb5_set_error_message(context, SDB_ERR_NOENTRY, + "samba_kdc_fetch: could not find KRBTGT number %u in DB!", + (unsigned)(krbtgt_number)); + return SDB_ERR_NOENTRY; + } + + ret = samba_kdc_message2entry(context, kdc_db_ctx, mem_ctx, + principal, SAMBA_KDC_ENT_TYPE_KRBTGT, + flags, kvno, realm_dn, msg, entry); + if (ret != 0) { + krb5_warnx(context, "samba_kdc_fetch: self krbtgt message2entry failed"); + } + return ret; + + } else { + enum trust_direction direction = UNKNOWN; + const char *realm = NULL; + + /* Either an inbound or outbound trust */ + + if (strcasecmp(lpcfg_realm(lp_ctx), realm_from_princ) == 0) { + /* look for inbound trust */ + direction = INBOUND; + realm = realm_princ_comp; + } else if (principal_comp_strcasecmp(context, principal, 1, lpcfg_realm(lp_ctx)) == 0) { + /* look for outbound trust */ + direction = OUTBOUND; + realm = realm_from_princ; + } else { + krb5_warnx(context, "samba_kdc_fetch: not our realm for trusts ('%s', '%s')", + realm_from_princ, + realm_princ_comp); + krb5_set_error_message(context, SDB_ERR_NOENTRY, "samba_kdc_fetch: not our realm for trusts ('%s', '%s')", + realm_from_princ, + realm_princ_comp); + return SDB_ERR_NOENTRY; + } + + /* Trusted domains are under CN=system */ + + ret = samba_kdc_lookup_trust(context, kdc_db_ctx->samdb, + mem_ctx, + realm, realm_dn, &msg); + + if (ret != 0) { + krb5_warnx(context, "samba_kdc_fetch: could not find principal in DB"); + krb5_set_error_message(context, ret, "samba_kdc_fetch: could not find principal in DB"); + return ret; + } + + ret = samba_kdc_trust_message2entry(context, kdc_db_ctx, mem_ctx, + direction, + realm_dn, flags, kvno, msg, entry); + if (ret != 0) { + krb5_warnx(context, "samba_kdc_fetch: trust_message2entry failed for %s", + ldb_dn_get_linearized(msg->dn)); + krb5_set_error_message(context, ret, "samba_kdc_fetch: " + "trust_message2entry failed for %s", + ldb_dn_get_linearized(msg->dn)); + } + return ret; + } + +} + +static krb5_error_code samba_kdc_lookup_server(krb5_context context, + struct samba_kdc_db_context *kdc_db_ctx, + TALLOC_CTX *mem_ctx, + krb5_const_principal principal, + unsigned flags, + const char **attrs, + struct ldb_dn **realm_dn, + struct ldb_message **msg) +{ + krb5_error_code ret; + if ((smb_krb5_principal_get_type(context, principal) != KRB5_NT_ENTERPRISE_PRINCIPAL) + && krb5_princ_size(context, principal) >= 2) { + /* 'normal server' case */ + int ldb_ret; + NTSTATUS nt_status; + struct ldb_dn *user_dn; + char *principal_string; + + ret = krb5_unparse_name_flags(context, principal, + KRB5_PRINCIPAL_UNPARSE_NO_REALM, + &principal_string); + if (ret != 0) { + return ret; + } + + /* At this point we may find the host is known to be + * in a different realm, so we should generate a + * referral instead */ + nt_status = crack_service_principal_name(kdc_db_ctx->samdb, + mem_ctx, principal_string, + &user_dn, realm_dn); + free(principal_string); + + if (!NT_STATUS_IS_OK(nt_status)) { + return SDB_ERR_NOENTRY; + } + + ldb_ret = dsdb_search_one(kdc_db_ctx->samdb, + mem_ctx, + msg, user_dn, LDB_SCOPE_BASE, + attrs, + DSDB_SEARCH_SHOW_EXTENDED_DN | DSDB_SEARCH_NO_GLOBAL_CATALOG, + "(objectClass=*)"); + if (ldb_ret != LDB_SUCCESS) { + return SDB_ERR_NOENTRY; + } + return 0; + } else if (!(flags & SDB_F_FOR_AS_REQ) + && smb_krb5_principal_get_type(context, principal) == KRB5_NT_ENTERPRISE_PRINCIPAL) { + /* + * The behaviour of accepting an + * KRB5_NT_ENTERPRISE_PRINCIPAL server principal + * containing a UPN only applies to TGS-REQ packets, + * not AS-REQ packets. + */ + return samba_kdc_lookup_client(context, kdc_db_ctx, + mem_ctx, principal, attrs, + realm_dn, msg); + } else { + /* + * This case is for: + * - the AS-REQ, where we only accept + * samAccountName based lookups for the server, no + * matter if the name is an + * KRB5_NT_ENTERPRISE_PRINCIPAL or not + * - for the TGS-REQ when we are not given an + * KRB5_NT_ENTERPRISE_PRINCIPAL, which also must + * only lookup samAccountName based names. + */ + int lret; + char *short_princ; + krb5_principal enterprise_principal = NULL; + krb5_const_principal used_principal = NULL; + char *name1 = NULL; + size_t len1 = 0; + char *filter = NULL; + + if (smb_krb5_principal_get_type(context, principal) == KRB5_NT_ENTERPRISE_PRINCIPAL) { + char *str = NULL; + /* Need to reparse the enterprise principal to find the real target */ + if (krb5_princ_size(context, principal) != 1) { + ret = KRB5_PARSE_MALFORMED; + krb5_set_error_message(context, ret, "samba_kdc_lookup_server: request for an " + "enterprise principal with wrong (%d) number of components", + krb5_princ_size(context, principal)); + return ret; + } + str = smb_krb5_principal_get_comp_string(mem_ctx, context, principal, 0); + if (str == NULL) { + return KRB5_PARSE_MALFORMED; + } + ret = krb5_parse_name(context, str, + &enterprise_principal); + talloc_free(str); + if (ret) { + return ret; + } + used_principal = enterprise_principal; + } else { + used_principal = principal; + } + + /* server as client principal case, but we must not lookup userPrincipalNames */ + *realm_dn = ldb_get_default_basedn(kdc_db_ctx->samdb); + + /* TODO: Check if it is our realm, otherwise give referral */ + + ret = krb5_unparse_name_flags(context, used_principal, + KRB5_PRINCIPAL_UNPARSE_NO_REALM | + KRB5_PRINCIPAL_UNPARSE_DISPLAY, + &short_princ); + used_principal = NULL; + krb5_free_principal(context, enterprise_principal); + enterprise_principal = NULL; + + if (ret != 0) { + krb5_set_error_message(context, ret, "samba_kdc_lookup_principal: could not parse principal"); + krb5_warnx(context, "samba_kdc_lookup_principal: could not parse principal"); + return ret; + } + + name1 = ldb_binary_encode_string(mem_ctx, short_princ); + SAFE_FREE(short_princ); + if (name1 == NULL) { + return ENOMEM; + } + len1 = strlen(name1); + if (len1 >= 1 && name1[len1 - 1] != '$') { + filter = talloc_asprintf(mem_ctx, + "(&(objectClass=user)(|(samAccountName=%s)(samAccountName=%s$)))", + name1, name1); + if (filter == NULL) { + return ENOMEM; + } + } else { + filter = talloc_asprintf(mem_ctx, + "(&(objectClass=user)(samAccountName=%s))", + name1); + if (filter == NULL) { + return ENOMEM; + } + } + + lret = dsdb_search_one(kdc_db_ctx->samdb, mem_ctx, msg, + *realm_dn, LDB_SCOPE_SUBTREE, + attrs, + DSDB_SEARCH_SHOW_EXTENDED_DN | DSDB_SEARCH_NO_GLOBAL_CATALOG, + "%s", filter); + if (lret == LDB_ERR_NO_SUCH_OBJECT) { + DEBUG(10, ("Failed to find an entry for %s filter:%s\n", + name1, filter)); + return SDB_ERR_NOENTRY; + } + if (lret == LDB_ERR_CONSTRAINT_VIOLATION) { + DEBUG(10, ("Failed to find unique entry for %s filter:%s\n", + name1, filter)); + return SDB_ERR_NOENTRY; + } + if (lret != LDB_SUCCESS) { + DEBUG(0, ("Failed single search for %s - %s\n", + name1, ldb_errstring(kdc_db_ctx->samdb))); + return SDB_ERR_NOENTRY; + } + return 0; + } + return SDB_ERR_NOENTRY; +} + + + +static krb5_error_code samba_kdc_fetch_server(krb5_context context, + struct samba_kdc_db_context *kdc_db_ctx, + TALLOC_CTX *mem_ctx, + krb5_const_principal principal, + unsigned flags, + krb5_kvno kvno, + struct sdb_entry *entry) +{ + krb5_error_code ret; + struct ldb_dn *realm_dn; + struct ldb_message *msg; + + ret = samba_kdc_lookup_server(context, kdc_db_ctx, mem_ctx, principal, + flags, server_attrs, &realm_dn, &msg); + if (ret != 0) { + return ret; + } + + ret = samba_kdc_message2entry(context, kdc_db_ctx, mem_ctx, + principal, SAMBA_KDC_ENT_TYPE_SERVER, + flags, kvno, + realm_dn, msg, entry); + if (ret != 0) { + char *client_name = NULL; + krb5_error_code code; + + code = krb5_unparse_name(context, principal, &client_name); + if (code == 0) { + krb5_warnx(context, + "samba_kdc_fetch: message2entry failed for " + "%s", + client_name); + } else { + krb5_warnx(context, + "samba_kdc_fetch: message2entry and " + "krb5_unparse_name failed"); + } + SAFE_FREE(client_name); + } + + return ret; +} + +static krb5_error_code samba_kdc_lookup_realm(krb5_context context, + struct samba_kdc_db_context *kdc_db_ctx, + TALLOC_CTX *mem_ctx, + krb5_const_principal principal, + unsigned flags, + struct sdb_entry *entry) +{ + TALLOC_CTX *frame = talloc_stackframe(); + NTSTATUS status; + krb5_error_code ret; + bool check_realm = false; + const char *realm = NULL; + struct dsdb_trust_routing_table *trt = NULL; + const struct lsa_TrustDomainInfoInfoEx *tdo = NULL; + unsigned int num_comp; + bool ok; + char *upper = NULL; + + num_comp = krb5_princ_size(context, principal); + + if (flags & SDB_F_GET_CLIENT) { + if (flags & SDB_F_FOR_AS_REQ) { + check_realm = true; + } + } + if (flags & SDB_F_GET_SERVER) { + if (flags & SDB_F_FOR_TGS_REQ) { + check_realm = true; + } + } + + if (!check_realm) { + TALLOC_FREE(frame); + return 0; + } + + realm = smb_krb5_principal_get_realm(frame, context, principal); + if (realm == NULL) { + TALLOC_FREE(frame); + return ENOMEM; + } + + /* + * The requested realm needs to be our own + */ + ok = lpcfg_is_my_domain_or_realm(kdc_db_ctx->lp_ctx, realm); + if (!ok) { + /* + * The request is not for us... + */ + TALLOC_FREE(frame); + return SDB_ERR_NOENTRY; + } + + if (smb_krb5_principal_get_type(context, principal) == KRB5_NT_ENTERPRISE_PRINCIPAL) { + char *principal_string = NULL; + krb5_principal enterprise_principal = NULL; + char *enterprise_realm = NULL; + + if (num_comp != 1) { + TALLOC_FREE(frame); + return SDB_ERR_NOENTRY; + } + + principal_string = smb_krb5_principal_get_comp_string(frame, context, + principal, 0); + if (principal_string == NULL) { + TALLOC_FREE(frame); + return ENOMEM; + } + + ret = krb5_parse_name(context, principal_string, + &enterprise_principal); + TALLOC_FREE(principal_string); + if (ret) { + TALLOC_FREE(frame); + return ret; + } + + enterprise_realm = smb_krb5_principal_get_realm( + frame, context, enterprise_principal); + krb5_free_principal(context, enterprise_principal); + if (enterprise_realm != NULL) { + realm = enterprise_realm; + } + } + + if (flags & SDB_F_GET_SERVER) { + char *service_realm = NULL; + + ret = principal_comp_strcmp(context, principal, 0, KRB5_TGS_NAME); + if (ret == 0) { + /* + * we need to search krbtgt/ locally + */ + TALLOC_FREE(frame); + return 0; + } + + /* + * We need to check the last component against the routing table. + * + * Note this works only with 2 or 3 component principals, e.g: + * + * servicePrincipalName: ldap/W2K8R2-219.bla.base + * servicePrincipalName: ldap/W2K8R2-219.bla.base/bla.base + * servicePrincipalName: ldap/W2K8R2-219.bla.base/ForestDnsZones.bla.base + * servicePrincipalName: ldap/W2K8R2-219.bla.base/DomainDnsZones.bla.base + */ + + if (num_comp == 2 || num_comp == 3) { + service_realm = smb_krb5_principal_get_comp_string(frame, + context, + principal, + num_comp - 1); + } + + if (service_realm != NULL) { + realm = service_realm; + } + } + + ok = lpcfg_is_my_domain_or_realm(kdc_db_ctx->lp_ctx, realm); + if (ok) { + /* + * skip the expensive routing lookup + */ + TALLOC_FREE(frame); + return 0; + } + + status = dsdb_trust_routing_table_load(kdc_db_ctx->samdb, + frame, &trt); + if (!NT_STATUS_IS_OK(status)) { + TALLOC_FREE(frame); + return EINVAL; + } + + tdo = dsdb_trust_routing_by_name(trt, realm); + if (tdo == NULL) { + /* + * This principal has to be local + */ + TALLOC_FREE(frame); + return 0; + } + + if (tdo->trust_attributes & LSA_TRUST_ATTRIBUTE_WITHIN_FOREST) { + /* + * TODO: handle the routing within the forest + * + * This should likely be handled in + * samba_kdc_message2entry() in case we're + * a global catalog. We'd need to check + * if realm_dn is our own domain and derive + * the dns domain name from realm_dn and check that + * against the routing table or fallback to + * the tdo we found here. + * + * But for now we don't support multiple domains + * in our forest correctly anyway. + * + * Just search in our local database. + */ + TALLOC_FREE(frame); + return 0; + } + + ZERO_STRUCTP(entry); + + ret = krb5_copy_principal(context, principal, + &entry->principal); + if (ret) { + TALLOC_FREE(frame); + return ret; + } + + upper = strupper_talloc(frame, tdo->domain_name.string); + if (upper == NULL) { + TALLOC_FREE(frame); + return ENOMEM; + } + + ret = smb_krb5_principal_set_realm(context, + entry->principal, + upper); + if (ret) { + TALLOC_FREE(frame); + return ret; + } + + TALLOC_FREE(frame); + return SDB_ERR_WRONG_REALM; +} + +krb5_error_code samba_kdc_fetch(krb5_context context, + struct samba_kdc_db_context *kdc_db_ctx, + krb5_const_principal principal, + unsigned flags, + krb5_kvno kvno, + struct sdb_entry *entry) +{ + krb5_error_code ret = SDB_ERR_NOENTRY; + TALLOC_CTX *mem_ctx; + + mem_ctx = talloc_named(kdc_db_ctx, 0, "samba_kdc_fetch context"); + if (!mem_ctx) { + ret = ENOMEM; + krb5_set_error_message(context, ret, "samba_kdc_fetch: talloc_named() failed!"); + return ret; + } + + ret = samba_kdc_lookup_realm(context, kdc_db_ctx, mem_ctx, + principal, flags, entry); + if (ret != 0) { + goto done; + } + + ret = SDB_ERR_NOENTRY; + + if (flags & SDB_F_GET_CLIENT) { + ret = samba_kdc_fetch_client(context, kdc_db_ctx, mem_ctx, principal, flags, kvno, entry); + if (ret != SDB_ERR_NOENTRY) goto done; + } + if (flags & SDB_F_GET_SERVER) { + /* krbtgt fits into this situation for trusted realms, and for resolving different versions of our own realm name */ + ret = samba_kdc_fetch_krbtgt(context, kdc_db_ctx, mem_ctx, principal, flags, kvno, entry); + if (ret != SDB_ERR_NOENTRY) goto done; + + /* We return 'no entry' if it does not start with krbtgt/, so move to the common case quickly */ + ret = samba_kdc_fetch_server(context, kdc_db_ctx, mem_ctx, principal, flags, kvno, entry); + if (ret != SDB_ERR_NOENTRY) goto done; + } + if (flags & SDB_F_GET_KRBTGT) { + ret = samba_kdc_fetch_krbtgt(context, kdc_db_ctx, mem_ctx, principal, flags, kvno, entry); + if (ret != SDB_ERR_NOENTRY) goto done; + } + +done: + talloc_free(mem_ctx); + return ret; +} + +struct samba_kdc_seq { + unsigned int index; + unsigned int count; + struct ldb_message **msgs; + struct ldb_dn *realm_dn; +}; + +static krb5_error_code samba_kdc_seq(krb5_context context, + struct samba_kdc_db_context *kdc_db_ctx, + struct sdb_entry *entry) +{ + krb5_error_code ret; + struct samba_kdc_seq *priv = kdc_db_ctx->seq_ctx; + const char *realm = lpcfg_realm(kdc_db_ctx->lp_ctx); + struct ldb_message *msg = NULL; + const char *sAMAccountName = NULL; + krb5_principal principal = NULL; + TALLOC_CTX *mem_ctx; + + if (!priv) { + return SDB_ERR_NOENTRY; + } + + mem_ctx = talloc_named(priv, 0, "samba_kdc_seq context"); + + if (!mem_ctx) { + ret = ENOMEM; + krb5_set_error_message(context, ret, "samba_kdc_seq: talloc_named() failed!"); + return ret; + } + + while (priv->index < priv->count) { + msg = priv->msgs[priv->index++]; + + sAMAccountName = ldb_msg_find_attr_as_string(msg, "sAMAccountName", NULL); + if (sAMAccountName != NULL) { + break; + } + } + + if (sAMAccountName == NULL) { + ret = SDB_ERR_NOENTRY; + goto out; + } + + ret = smb_krb5_make_principal(context, &principal, + realm, sAMAccountName, NULL); + if (ret != 0) { + goto out; + } + + ret = samba_kdc_message2entry(context, kdc_db_ctx, mem_ctx, + principal, SAMBA_KDC_ENT_TYPE_ANY, + SDB_F_ADMIN_DATA|SDB_F_GET_ANY, + 0 /* kvno */, + priv->realm_dn, msg, entry); + +out: + if (principal != NULL) { + krb5_free_principal(context, principal); + } + + if (ret != 0) { + TALLOC_FREE(priv); + kdc_db_ctx->seq_ctx = NULL; + } else { + talloc_free(mem_ctx); + } + + return ret; +} + +krb5_error_code samba_kdc_firstkey(krb5_context context, + struct samba_kdc_db_context *kdc_db_ctx, + struct sdb_entry *entry) +{ + struct ldb_context *ldb_ctx = kdc_db_ctx->samdb; + struct samba_kdc_seq *priv = kdc_db_ctx->seq_ctx; + char *realm; + struct ldb_result *res = NULL; + krb5_error_code ret; + TALLOC_CTX *mem_ctx; + int lret; + + if (priv) { + TALLOC_FREE(priv); + kdc_db_ctx->seq_ctx = NULL; + } + + priv = (struct samba_kdc_seq *) talloc(kdc_db_ctx, struct samba_kdc_seq); + if (!priv) { + ret = ENOMEM; + krb5_set_error_message(context, ret, "talloc: out of memory"); + return ret; + } + + priv->index = 0; + priv->msgs = NULL; + priv->realm_dn = ldb_get_default_basedn(ldb_ctx); + priv->count = 0; + + mem_ctx = talloc_named(priv, 0, "samba_kdc_firstkey context"); + + if (!mem_ctx) { + ret = ENOMEM; + krb5_set_error_message(context, ret, "samba_kdc_firstkey: talloc_named() failed!"); + return ret; + } + + ret = krb5_get_default_realm(context, &realm); + if (ret != 0) { + TALLOC_FREE(priv); + return ret; + } + krb5_free_default_realm(context, realm); + + lret = dsdb_search(ldb_ctx, priv, &res, + priv->realm_dn, LDB_SCOPE_SUBTREE, user_attrs, + DSDB_SEARCH_NO_GLOBAL_CATALOG, + "(objectClass=user)"); + + if (lret != LDB_SUCCESS) { + TALLOC_FREE(priv); + return SDB_ERR_NOENTRY; + } + + priv->count = res->count; + priv->msgs = talloc_steal(priv, res->msgs); + talloc_free(res); + + kdc_db_ctx->seq_ctx = priv; + + ret = samba_kdc_seq(context, kdc_db_ctx, entry); + + if (ret != 0) { + TALLOC_FREE(priv); + kdc_db_ctx->seq_ctx = NULL; + } else { + talloc_free(mem_ctx); + } + return ret; +} + +krb5_error_code samba_kdc_nextkey(krb5_context context, + struct samba_kdc_db_context *kdc_db_ctx, + struct sdb_entry *entry) +{ + return samba_kdc_seq(context, kdc_db_ctx, entry); +} + +/* Check if a given entry may delegate or do s4u2self to this target principal + * + * The safest way to determine 'self' is to check the DB record made at + * the time the principal was presented to the KDC. + */ +krb5_error_code +samba_kdc_check_client_matches_target_service(krb5_context context, + struct samba_kdc_entry *skdc_entry_client, + struct samba_kdc_entry *skdc_entry_server_target) +{ + struct dom_sid *orig_sid; + struct dom_sid *target_sid; + TALLOC_CTX *frame = talloc_stackframe(); + + orig_sid = samdb_result_dom_sid(frame, + skdc_entry_client->msg, + "objectSid"); + target_sid = samdb_result_dom_sid(frame, + skdc_entry_server_target->msg, + "objectSid"); + + /* + * Allow delegation to the same record (representing a + * principal), even if by a different name. The easy and safe + * way to prove this is by SID comparison + */ + if (!(orig_sid && target_sid && dom_sid_equal(orig_sid, target_sid))) { + talloc_free(frame); + return KRB5KRB_AP_ERR_BADMATCH; + } + + talloc_free(frame); + return 0; +} + +/* Certificates printed by a the Certificate Authority might have a + * slightly different form of the user principal name to that in the + * database. Allow a mismatch where they both refer to the same + * SID */ + +krb5_error_code +samba_kdc_check_pkinit_ms_upn_match(krb5_context context, + struct samba_kdc_db_context *kdc_db_ctx, + struct samba_kdc_entry *skdc_entry, + krb5_const_principal certificate_principal) +{ + krb5_error_code ret; + struct ldb_dn *realm_dn; + struct ldb_message *msg; + struct dom_sid *orig_sid; + struct dom_sid *target_sid; + const char *ms_upn_check_attrs[] = { + "objectSid", NULL + }; + + TALLOC_CTX *mem_ctx = talloc_named(kdc_db_ctx, 0, "samba_kdc_check_pkinit_ms_upn_match"); + + if (!mem_ctx) { + ret = ENOMEM; + krb5_set_error_message(context, ret, "samba_kdc_fetch: talloc_named() failed!"); + return ret; + } + + ret = samba_kdc_lookup_client(context, kdc_db_ctx, + mem_ctx, certificate_principal, + ms_upn_check_attrs, &realm_dn, &msg); + + if (ret != 0) { + talloc_free(mem_ctx); + return ret; + } + + orig_sid = samdb_result_dom_sid(mem_ctx, skdc_entry->msg, "objectSid"); + target_sid = samdb_result_dom_sid(mem_ctx, msg, "objectSid"); + + /* Consider these to be the same principal, even if by a different + * name. The easy and safe way to prove this is by SID + * comparison */ + if (!(orig_sid && target_sid && dom_sid_equal(orig_sid, target_sid))) { + talloc_free(mem_ctx); +#if defined(KRB5KDC_ERR_CLIENT_NAME_MISMATCH) /* MIT */ + return KRB5KDC_ERR_CLIENT_NAME_MISMATCH; +#else /* Heimdal (where this is an enum) */ + return KRB5_KDC_ERR_CLIENT_NAME_MISMATCH; +#endif + } + + talloc_free(mem_ctx); + return ret; +} + +/* + * Check if a given entry may delegate to this target principal + * with S4U2Proxy. + */ +krb5_error_code +samba_kdc_check_s4u2proxy(krb5_context context, + struct samba_kdc_db_context *kdc_db_ctx, + struct samba_kdc_entry *skdc_entry, + krb5_const_principal target_principal) +{ + krb5_error_code ret; + char *tmp = NULL; + const char *client_dn = NULL; + const char *target_principal_name = NULL; + struct ldb_message_element *el; + struct ldb_val val; + unsigned int i; + bool found = false; + + TALLOC_CTX *mem_ctx = talloc_named(kdc_db_ctx, 0, "samba_kdc_check_s4u2proxy"); + + if (!mem_ctx) { + ret = ENOMEM; + krb5_set_error_message(context, ret, + "samba_kdc_check_s4u2proxy:" + " talloc_named() failed!"); + return ret; + } + + client_dn = ldb_dn_get_linearized(skdc_entry->msg->dn); + if (!client_dn) { + if (errno == 0) { + errno = ENOMEM; + } + ret = errno; + krb5_set_error_message(context, ret, + "samba_kdc_check_s4u2proxy:" + " ldb_dn_get_linearized() failed!"); + return ret; + } + + el = ldb_msg_find_element(skdc_entry->msg, "msDS-AllowedToDelegateTo"); + if (el == NULL) { + ret = ENOENT; + goto bad_option; + } + SMB_ASSERT(el->num_values != 0); + + /* + * This is the Microsoft forwardable flag behavior. + * + * If the proxy (target) principal is NULL, and we have any authorized + * delegation target, allow to forward. + */ + if (target_principal == NULL) { + return 0; + } + + + /* + * The main heimdal code already checked that the target_principal + * belongs to the same realm as the client. + * + * So we just need the principal without the realm, + * as that is what is configured in the "msDS-AllowedToDelegateTo" + * attribute. + */ + ret = krb5_unparse_name_flags(context, target_principal, + KRB5_PRINCIPAL_UNPARSE_NO_REALM, &tmp); + if (ret) { + talloc_free(mem_ctx); + krb5_set_error_message(context, ret, + "samba_kdc_check_s4u2proxy:" + " krb5_unparse_name() failed!"); + return ret; + } + DEBUG(10,("samba_kdc_check_s4u2proxy: client[%s] for target[%s]\n", + client_dn, tmp)); + + target_principal_name = talloc_strdup(mem_ctx, tmp); + SAFE_FREE(tmp); + if (target_principal_name == NULL) { + ret = ENOMEM; + krb5_set_error_message(context, ret, + "samba_kdc_check_s4u2proxy:" + " talloc_strdup() failed!"); + return ret; + } + + val = data_blob_string_const(target_principal_name); + + for (i=0; i<el->num_values; i++) { + struct ldb_val *val1 = &val; + struct ldb_val *val2 = &el->values[i]; + int cmp; + + if (val1->length != val2->length) { + continue; + } + + cmp = strncasecmp((const char *)val1->data, + (const char *)val2->data, + val1->length); + if (cmp != 0) { + continue; + } + + found = true; + break; + } + + if (!found) { + ret = ENOENT; + goto bad_option; + } + + DEBUG(10,("samba_kdc_check_s4u2proxy: client[%s] allowed target[%s]\n", + client_dn, tmp)); + talloc_free(mem_ctx); + return 0; + +bad_option: + krb5_set_error_message(context, ret, + "samba_kdc_check_s4u2proxy: client[%s] " + "not allowed for delegation to target[%s]", + client_dn, + target_principal_name); + talloc_free(mem_ctx); + return KRB5KDC_ERR_BADOPTION; +} + +/* + * This method is called for S4U2Proxy requests and implements the + * resource-based constrained delegation variant, which can support + * cross-realm delegation. + */ +krb5_error_code samba_kdc_check_s4u2proxy_rbcd( + krb5_context context, + struct samba_kdc_db_context *kdc_db_ctx, + krb5_const_principal client_principal, + krb5_const_principal server_principal, + krb5_pac header_pac, + struct samba_kdc_entry *proxy_skdc_entry) +{ + krb5_error_code code; + enum ndr_err_code ndr_err; + char *client_name = NULL; + char *server_name = NULL; + const char *proxy_dn = NULL; + const DATA_BLOB *data = NULL; + struct security_descriptor *rbcd_security_descriptor = NULL; + struct auth_user_info_dc *user_info_dc = NULL; + struct auth_session_info *session_info = NULL; + uint32_t session_info_flags = AUTH_SESSION_INFO_SIMPLE_PRIVILEGES; + /* + * Testing shows that although Windows grants SEC_ADS_GENERIC_ALL access + * in security descriptors it creates for RBCD, its KDC only requires + * SEC_ADS_CONTROL_ACCESS for the access check to succeed. + */ + uint32_t access_desired = SEC_ADS_CONTROL_ACCESS; + uint32_t access_granted = 0; + NTSTATUS nt_status; + TALLOC_CTX *mem_ctx = NULL; + + mem_ctx = talloc_named(kdc_db_ctx, + 0, + "samba_kdc_check_s4u2proxy_rbcd"); + if (mem_ctx == NULL) { + errno = ENOMEM; + code = errno; + + return code; + } + + proxy_dn = ldb_dn_get_linearized(proxy_skdc_entry->msg->dn); + if (proxy_dn == NULL) { + DBG_ERR("ldb_dn_get_linearized failed for proxy_dn!\n"); + TALLOC_FREE(mem_ctx); + if (errno == 0) { + errno = ENOMEM; + } + code = errno; + + goto out; + } + + rbcd_security_descriptor = talloc_zero(mem_ctx, + struct security_descriptor); + if (rbcd_security_descriptor == NULL) { + errno = ENOMEM; + code = errno; + + goto out; + } + + code = krb5_unparse_name_flags(context, + client_principal, + KRB5_PRINCIPAL_UNPARSE_DISPLAY, + &client_name); + if (code != 0) { + DBG_ERR("Unable to parse client_principal!\n"); + goto out; + } + + code = krb5_unparse_name_flags(context, + server_principal, + KRB5_PRINCIPAL_UNPARSE_DISPLAY, + &server_name); + if (code != 0) { + DBG_ERR("Unable to parse server_principal!\n"); + SAFE_FREE(client_name); + goto out; + } + + DBG_INFO("Check delegation from client[%s] to server[%s] via " + "proxy[%s]\n", + client_name, + server_name, + proxy_dn); + + code = kerberos_pac_to_user_info_dc(mem_ctx, + header_pac, + context, + &user_info_dc, + NULL, + NULL); + if (code != 0) { + goto out; + } + + if (user_info_dc->info->authenticated) { + session_info_flags |= AUTH_SESSION_INFO_AUTHENTICATED; + } + + nt_status = auth_generate_session_info(mem_ctx, + kdc_db_ctx->lp_ctx, + kdc_db_ctx->samdb, + user_info_dc, + session_info_flags, + &session_info); + if (!NT_STATUS_IS_OK(nt_status)) { + code = map_errno_from_nt_status(nt_status); + goto out; + } + + data = ldb_msg_find_ldb_val(proxy_skdc_entry->msg, + "msDS-AllowedToActOnBehalfOfOtherIdentity"); + if (data == NULL) { + DBG_ERR("Could not find security descriptor " + "msDS-AllowedToActOnBehalfOfOtherIdentity in " + "proxy[%s]\n", + proxy_dn); + code = KRB5KDC_ERR_BADOPTION; + goto out; + } + + ndr_err = ndr_pull_struct_blob( + data, + mem_ctx, + rbcd_security_descriptor, + (ndr_pull_flags_fn_t)ndr_pull_security_descriptor); + if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) { + errno = ndr_map_error2errno(ndr_err); + DBG_ERR("Failed to unmarshall " + "msDS-AllowedToActOnBehalfOfOtherIdentity " + "security descriptor of proxy[%s]\n", + proxy_dn); + code = KRB5KDC_ERR_BADOPTION; + goto out; + } + + if (DEBUGLEVEL >= 10) { + NDR_PRINT_DEBUG(security_token, session_info->security_token); + NDR_PRINT_DEBUG(security_descriptor, rbcd_security_descriptor); + } + + nt_status = sec_access_check_ds(rbcd_security_descriptor, + session_info->security_token, + access_desired, + &access_granted, + NULL, + NULL); + + if (!NT_STATUS_IS_OK(nt_status)) { + DBG_WARNING("RBCD: sec_access_check_ds(access_desired=%#08x, " + "access_granted:%#08x) failed with: %s\n", + access_desired, + access_granted, + nt_errstr(nt_status)); + + code = KRB5KDC_ERR_BADOPTION; + goto out; + } + + DBG_NOTICE("RBCD: Access granted for client[%s]\n", client_name); + + code = 0; +out: + SAFE_FREE(client_name); + SAFE_FREE(server_name); + + TALLOC_FREE(mem_ctx); + return code; +} + +NTSTATUS samba_kdc_setup_db_ctx(TALLOC_CTX *mem_ctx, struct samba_kdc_base_context *base_ctx, + struct samba_kdc_db_context **kdc_db_ctx_out) +{ + int ldb_ret; + struct ldb_message *msg; + struct auth_session_info *session_info; + struct samba_kdc_db_context *kdc_db_ctx; + /* The idea here is very simple. Using Kerberos to + * authenticate the KDC to the LDAP server is higly likely to + * be circular. + * + * In future we may set this up to use EXERNAL and SSL + * certificates, for now it will almost certainly be NTLMSSP_SET_USERNAME + */ + + kdc_db_ctx = talloc_zero(mem_ctx, struct samba_kdc_db_context); + if (kdc_db_ctx == NULL) { + return NT_STATUS_NO_MEMORY; + } + kdc_db_ctx->ev_ctx = base_ctx->ev_ctx; + kdc_db_ctx->lp_ctx = base_ctx->lp_ctx; + kdc_db_ctx->msg_ctx = base_ctx->msg_ctx; + + /* get default kdc policy */ + lpcfg_default_kdc_policy(mem_ctx, + base_ctx->lp_ctx, + &kdc_db_ctx->policy.svc_tkt_lifetime, + &kdc_db_ctx->policy.usr_tkt_lifetime, + &kdc_db_ctx->policy.renewal_lifetime); + + session_info = system_session(kdc_db_ctx->lp_ctx); + if (session_info == NULL) { + return NT_STATUS_INTERNAL_ERROR; + } + + /* Setup the link to secrets.ldb */ + + kdc_db_ctx->secrets_db = secrets_db_connect(kdc_db_ctx, + base_ctx->lp_ctx); + if (kdc_db_ctx->secrets_db == NULL) { + DEBUG(1, ("samba_kdc_setup_db_ctx: " + "Cannot open secrets.ldb for KDC backend!")); + talloc_free(kdc_db_ctx); + return NT_STATUS_CANT_ACCESS_DOMAIN_INFO; + } + + kdc_db_ctx->fx_cookie_dn = ldb_dn_new(kdc_db_ctx, + kdc_db_ctx->secrets_db, + "CN=FX Cookie"); + + /* Setup the link to LDB */ + kdc_db_ctx->samdb = samdb_connect(kdc_db_ctx, + base_ctx->ev_ctx, + base_ctx->lp_ctx, + session_info, + NULL, + 0); + if (kdc_db_ctx->samdb == NULL) { + DEBUG(1, ("samba_kdc_setup_db_ctx: Cannot open samdb for KDC backend!")); + talloc_free(kdc_db_ctx); + return NT_STATUS_CANT_ACCESS_DOMAIN_INFO; + } + + /* Find out our own krbtgt kvno */ + ldb_ret = samdb_rodc(kdc_db_ctx->samdb, &kdc_db_ctx->rodc); + if (ldb_ret != LDB_SUCCESS) { + DEBUG(1, ("samba_kdc_setup_db_ctx: Cannot determine if we are an RODC in KDC backend: %s\n", + ldb_errstring(kdc_db_ctx->samdb))); + talloc_free(kdc_db_ctx); + return NT_STATUS_CANT_ACCESS_DOMAIN_INFO; + } + if (kdc_db_ctx->rodc) { + int my_krbtgt_number; + const char *secondary_keytab[] = { "msDS-SecondaryKrbTgtNumber", NULL }; + struct ldb_dn *account_dn; + struct ldb_dn *server_dn = samdb_server_dn(kdc_db_ctx->samdb, kdc_db_ctx); + if (!server_dn) { + DEBUG(1, ("samba_kdc_setup_db_ctx: Cannot determine server DN in KDC backend: %s\n", + ldb_errstring(kdc_db_ctx->samdb))); + talloc_free(kdc_db_ctx); + return NT_STATUS_CANT_ACCESS_DOMAIN_INFO; + } + + ldb_ret = samdb_reference_dn(kdc_db_ctx->samdb, kdc_db_ctx, server_dn, + "serverReference", &account_dn); + if (ldb_ret != LDB_SUCCESS) { + DEBUG(1, ("samba_kdc_setup_db_ctx: Cannot determine server account in KDC backend: %s\n", + ldb_errstring(kdc_db_ctx->samdb))); + talloc_free(kdc_db_ctx); + return NT_STATUS_CANT_ACCESS_DOMAIN_INFO; + } + + ldb_ret = samdb_reference_dn(kdc_db_ctx->samdb, kdc_db_ctx, account_dn, + "msDS-KrbTgtLink", &kdc_db_ctx->krbtgt_dn); + talloc_free(account_dn); + if (ldb_ret != LDB_SUCCESS) { + DEBUG(1, ("samba_kdc_setup_db_ctx: Cannot determine RODC krbtgt account in KDC backend: %s\n", + ldb_errstring(kdc_db_ctx->samdb))); + talloc_free(kdc_db_ctx); + return NT_STATUS_CANT_ACCESS_DOMAIN_INFO; + } + + ldb_ret = dsdb_search_one(kdc_db_ctx->samdb, kdc_db_ctx, + &msg, kdc_db_ctx->krbtgt_dn, LDB_SCOPE_BASE, + secondary_keytab, + DSDB_SEARCH_NO_GLOBAL_CATALOG, + "(&(objectClass=user)(msDS-SecondaryKrbTgtNumber=*))"); + if (ldb_ret != LDB_SUCCESS) { + DEBUG(1, ("samba_kdc_setup_db_ctx: Cannot read krbtgt account %s in KDC backend to get msDS-SecondaryKrbTgtNumber: %s: %s\n", + ldb_dn_get_linearized(kdc_db_ctx->krbtgt_dn), + ldb_errstring(kdc_db_ctx->samdb), + ldb_strerror(ldb_ret))); + talloc_free(kdc_db_ctx); + return NT_STATUS_CANT_ACCESS_DOMAIN_INFO; + } + my_krbtgt_number = ldb_msg_find_attr_as_int(msg, "msDS-SecondaryKrbTgtNumber", -1); + if (my_krbtgt_number == -1) { + DEBUG(1, ("samba_kdc_setup_db_ctx: Cannot read msDS-SecondaryKrbTgtNumber from krbtgt account %s in KDC backend: got %d\n", + ldb_dn_get_linearized(kdc_db_ctx->krbtgt_dn), + my_krbtgt_number)); + talloc_free(kdc_db_ctx); + return NT_STATUS_CANT_ACCESS_DOMAIN_INFO; + } + kdc_db_ctx->my_krbtgt_number = my_krbtgt_number; + + } else { + kdc_db_ctx->my_krbtgt_number = 0; + ldb_ret = dsdb_search_one(kdc_db_ctx->samdb, kdc_db_ctx, + &msg, + ldb_get_default_basedn(kdc_db_ctx->samdb), + LDB_SCOPE_SUBTREE, + krbtgt_attrs, + DSDB_SEARCH_NO_GLOBAL_CATALOG, + "(&(objectClass=user)(samAccountName=krbtgt))"); + + if (ldb_ret != LDB_SUCCESS) { + DEBUG(1, ("samba_kdc_fetch: could not find own KRBTGT in DB: %s\n", ldb_errstring(kdc_db_ctx->samdb))); + talloc_free(kdc_db_ctx); + return NT_STATUS_CANT_ACCESS_DOMAIN_INFO; + } + kdc_db_ctx->krbtgt_dn = talloc_steal(kdc_db_ctx, msg->dn); + kdc_db_ctx->my_krbtgt_number = 0; + talloc_free(msg); + } + *kdc_db_ctx_out = kdc_db_ctx; + return NT_STATUS_OK; +} + +krb5_error_code dsdb_extract_aes_256_key(krb5_context context, + TALLOC_CTX *mem_ctx, + const struct ldb_message *msg, + uint32_t user_account_control, + const uint32_t *kvno, + uint32_t *kvno_out, + DATA_BLOB *aes_256_key, + DATA_BLOB *salt) +{ + krb5_error_code krb5_ret; + uint32_t supported_enctypes; + unsigned flags = SDB_F_GET_CLIENT; + struct sdb_entry sentry = {}; + + if (kvno != NULL) { + flags |= SDB_F_KVNO_SPECIFIED; + } + + krb5_ret = samba_kdc_message2entry_keys(context, + mem_ctx, + msg, + false, /* is_krbtgt */ + false, /* is_rodc */ + user_account_control, + SAMBA_KDC_ENT_TYPE_CLIENT, + flags, + (kvno != NULL) ? *kvno : 0, + &sentry, + ENC_HMAC_SHA1_96_AES256, + &supported_enctypes); + if (krb5_ret != 0) { + DBG_ERR("Failed to parse supplementalCredentials " + "of %s with %s kvno using " + "ENCTYPE_HMAC_SHA1_96_AES256 " + "Kerberos Key: %s\n", + ldb_dn_get_linearized(msg->dn), + (kvno != NULL) ? "previous" : "current", + krb5_get_error_message(context, + krb5_ret)); + return krb5_ret; + } + + if ((supported_enctypes & ENC_HMAC_SHA1_96_AES256) == 0 || + sentry.keys.len != 1) { + DBG_INFO("Failed to find a ENCTYPE_HMAC_SHA1_96_AES256 " + "key in supplementalCredentials " + "of %s at KVNO %u (got %u keys, expected 1)\n", + ldb_dn_get_linearized(msg->dn), + sentry.kvno, + sentry.keys.len); + sdb_entry_free(&sentry); + return ENOENT; + } + + if (sentry.keys.val[0].salt == NULL) { + DBG_INFO("Failed to find a salt in " + "supplementalCredentials " + "of %s at KVNO %u\n", + ldb_dn_get_linearized(msg->dn), + sentry.kvno); + sdb_entry_free(&sentry); + return ENOENT; + } + + if (aes_256_key != NULL) { + *aes_256_key = data_blob_talloc(mem_ctx, + KRB5_KEY_DATA(&sentry.keys.val[0].key), + KRB5_KEY_LENGTH(&sentry.keys.val[0].key)); + if (aes_256_key->data == NULL) { + sdb_entry_free(&sentry); + return ENOMEM; + } + talloc_keep_secret(aes_256_key->data); + } + + if (salt != NULL) { + *salt = data_blob_talloc(mem_ctx, + sentry.keys.val[0].salt->salt.data, + sentry.keys.val[0].salt->salt.length); + if (salt->data == NULL) { + sdb_entry_free(&sentry); + return ENOMEM; + } + } + + if (kvno_out != NULL) { + *kvno_out = sentry.kvno; + } + + sdb_entry_free(&sentry); + + return 0; +} |