/* Unix SMB/CIFS implementation. PAC Glue between Samba and the KDC Copyright (C) Andrew Bartlett 2005-2009 Copyright (C) Simo Sorce 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 . */ #include "includes.h" #include "kdc/kdc-glue.h" #include "kdc/db-glue.h" #include "kdc/pac-glue.h" #include "sdb.h" #include "sdb_hdb.h" #include "librpc/gen_ndr/auth.h" #include #include "lib/replace/system/filesys.h" #undef DBGC_CLASS #define DBGC_CLASS DBGC_KERBEROS static bool samba_wdc_is_s4u2self_req(astgs_request_t r) { krb5_kdc_configuration *config = kdc_request_get_config((kdc_request_t)r); const KDC_REQ *req = kdc_request_get_req(r); const PA_DATA *pa_for_user = NULL; if (req->msg_type != krb_tgs_req) { return false; } if (config->enable_fast && req->padata != NULL) { const PA_DATA *pa_fx_fast = NULL; int idx = 0; pa_fx_fast = krb5_find_padata(req->padata->val, req->padata->len, KRB5_PADATA_FX_FAST, &idx); if (pa_fx_fast != NULL) { /* * We're in the outer request * with KRB5_PADATA_FX_FAST * if fast is enabled we'll * process the s4u2self * request only in the * inner request. */ return false; } } if (req->padata != NULL) { int idx = 0; pa_for_user = krb5_find_padata(req->padata->val, req->padata->len, KRB5_PADATA_FOR_USER, &idx); } if (pa_for_user != NULL) { return true; } return false; } /* * Given the right private pointer from hdb_samba4, * get a PAC from the attached ldb messages. * * For PKINIT we also get pk_reply_key and can add PAC_CREDENTIAL_INFO. */ static krb5_error_code samba_wdc_get_pac(void *priv, astgs_request_t r, hdb_entry *client, hdb_entry *server, const krb5_keyblock *pk_reply_key, uint64_t pac_attributes, krb5_pac *pac) { krb5_context context = kdc_request_get_context((kdc_request_t)r); TALLOC_CTX *mem_ctx; DATA_BLOB *logon_blob = NULL; DATA_BLOB *cred_ndr = NULL; DATA_BLOB **cred_ndr_ptr = NULL; DATA_BLOB _cred_blob = data_blob_null; DATA_BLOB *cred_blob = NULL; DATA_BLOB *upn_blob = NULL; DATA_BLOB *pac_attrs_blob = NULL; DATA_BLOB *requester_sid_blob = NULL; DATA_BLOB *client_claims_blob = NULL; krb5_error_code ret; NTSTATUS nt_status; struct samba_kdc_entry *skdc_entry = talloc_get_type_abort(client->context, struct samba_kdc_entry); const struct samba_kdc_entry *server_entry = talloc_get_type_abort(server->context, struct samba_kdc_entry); bool is_krbtgt = krb5_principal_is_krbtgt(context, server->principal); /* Only include resource groups in a service ticket. */ enum auth_group_inclusion group_inclusion; bool is_s4u2self = samba_wdc_is_s4u2self_req(r); enum samba_asserted_identity asserted_identity = (is_s4u2self) ? SAMBA_ASSERTED_IDENTITY_SERVICE : SAMBA_ASSERTED_IDENTITY_AUTHENTICATION_AUTHORITY; const enum samba_claims_valid claims_valid = SAMBA_CLAIMS_VALID_INCLUDE; const enum samba_compounded_auth compounded_auth = SAMBA_COMPOUNDED_AUTH_EXCLUDE; struct auth_user_info_dc *user_info_dc = NULL; /* Only include resource groups in a service ticket. */ if (is_krbtgt) { group_inclusion = AUTH_EXCLUDE_RESOURCE_GROUPS; } else if (server_entry->supported_enctypes & KERB_ENCTYPE_RESOURCE_SID_COMPRESSION_DISABLED) { group_inclusion = AUTH_INCLUDE_RESOURCE_GROUPS; } else { group_inclusion = AUTH_INCLUDE_RESOURCE_GROUPS_COMPRESSED; } mem_ctx = talloc_named(client->context, 0, "samba_wdc_get_pac context"); if (!mem_ctx) { return ENOMEM; } if (pk_reply_key != NULL) { cred_ndr_ptr = &cred_ndr; } nt_status = samba_kdc_get_user_info_dc(mem_ctx, skdc_entry, asserted_identity, claims_valid, compounded_auth, &user_info_dc); if (!NT_STATUS_IS_OK(nt_status)) { talloc_free(mem_ctx); return EINVAL; } nt_status = samba_kdc_get_logon_info_blob(mem_ctx, user_info_dc, group_inclusion, &logon_blob); if (!NT_STATUS_IS_OK(nt_status)) { talloc_free(mem_ctx); return EINVAL; } if (cred_ndr_ptr != NULL) { nt_status = samba_kdc_get_cred_ndr_blob(mem_ctx, skdc_entry, cred_ndr_ptr); if (!NT_STATUS_IS_OK(nt_status)) { talloc_free(mem_ctx); return EINVAL; } } nt_status = samba_kdc_get_upn_info_blob(mem_ctx, user_info_dc, &upn_blob); if (!NT_STATUS_IS_OK(nt_status)) { talloc_free(mem_ctx); return EINVAL; } if (is_krbtgt) { nt_status = samba_kdc_get_pac_attrs_blob(mem_ctx, pac_attributes, &pac_attrs_blob); if (!NT_STATUS_IS_OK(nt_status)) { talloc_free(mem_ctx); return EINVAL; } nt_status = samba_kdc_get_requester_sid_blob(mem_ctx, user_info_dc, &requester_sid_blob); if (!NT_STATUS_IS_OK(nt_status)) { talloc_free(mem_ctx); return EINVAL; } } nt_status = samba_kdc_get_claims_blob(mem_ctx, skdc_entry, &client_claims_blob); if (!NT_STATUS_IS_OK(nt_status)) { talloc_free(mem_ctx); return EINVAL; } if (pk_reply_key != NULL && cred_ndr != NULL) { ret = samba_kdc_encrypt_pac_credentials(context, pk_reply_key, cred_ndr, mem_ctx, &_cred_blob); if (ret != 0) { talloc_free(mem_ctx); return ret; } cred_blob = &_cred_blob; } ret = krb5_pac_init(context, pac); if (ret != 0) { talloc_free(mem_ctx); return ret; } ret = samba_make_krb5_pac(context, logon_blob, cred_blob, upn_blob, pac_attrs_blob, requester_sid_blob, NULL, client_claims_blob, NULL, NULL, *pac); talloc_free(mem_ctx); return ret; } static krb5_error_code samba_wdc_verify_pac2(astgs_request_t r, const krb5_principal delegated_proxy_principal, const hdb_entry *client, const hdb_entry *server, const hdb_entry *krbtgt, const krb5_pac pac, krb5_cksumtype ctype, const hdb_entry *device, krb5_const_pac *device_pac, krb5_boolean *is_trusted_out) { krb5_context context = kdc_request_get_context((kdc_request_t)r); struct samba_kdc_entry *client_skdc_entry = NULL; struct samba_kdc_entry *device_skdc_entry = NULL; struct samba_kdc_entry *krbtgt_skdc_entry = talloc_get_type_abort(krbtgt->context, struct samba_kdc_entry); TALLOC_CTX *mem_ctx = NULL; krb5_error_code ret; bool is_s4u2self = samba_wdc_is_s4u2self_req(r); bool is_in_db = false; bool is_trusted = false; uint32_t flags = 0; mem_ctx = talloc_named(NULL, 0, "samba_wdc_verify_pac2 context"); if (mem_ctx == NULL) { return ENOMEM; } if (client != NULL) { client_skdc_entry = talloc_get_type_abort(client->context, struct samba_kdc_entry); } if (device != NULL) { device_skdc_entry = talloc_get_type_abort(device->context, struct samba_kdc_entry); } /* * If the krbtgt was generated by an RODC, and we are not that * RODC, then we need to regenerate the PAC - we can't trust * it, and confirm that the RODC was permitted to print this ticket * * Becasue of the samba_kdc_validate_pac_blob() step we can be * sure that the record in 'client' matches the SID in the * original PAC. */ ret = samba_krbtgt_is_in_db(krbtgt_skdc_entry, &is_in_db, &is_trusted); if (ret != 0) { goto out; } if (is_s4u2self) { flags |= SAMBA_KDC_FLAG_PROTOCOL_TRANSITION; } if (delegated_proxy_principal != NULL) { krb5_enctype etype; Key *key = NULL; if (!is_in_db) { /* * The RODC-issued PAC was signed by a KDC entry that we * don't have a key for. The server signature is not * trustworthy, since it could have been created by the * server we got the ticket from. We must not proceed as * otherwise the ticket signature is unchecked. */ ret = HDB_ERR_NOT_FOUND_HERE; goto out; } /* Fetch the correct key depending on the checksum type. */ if (ctype == CKSUMTYPE_HMAC_MD5) { etype = ENCTYPE_ARCFOUR_HMAC; } else { ret = krb5_cksumtype_to_enctype(context, ctype, &etype); if (ret != 0) { goto out; } } ret = hdb_enctype2key(context, krbtgt, NULL, etype, &key); if (ret != 0) { goto out; } /* Check the KDC, whole-PAC and ticket signatures. */ ret = krb5_pac_verify(context, pac, 0, NULL, NULL, &key->key); if (ret != 0) { DEBUG(1, ("PAC KDC signature failed to verify\n")); goto out; } flags |= SAMBA_KDC_FLAG_CONSTRAINED_DELEGATION; } if (is_trusted) { flags |= SAMBA_KDC_FLAG_KRBTGT_IS_TRUSTED; } if (is_in_db) { flags |= SAMBA_KDC_FLAG_KRBTGT_IN_DB; } ret = samba_kdc_verify_pac(mem_ctx, context, flags, client_skdc_entry, krbtgt_skdc_entry, device_skdc_entry, device_pac, pac); if (ret != 0) { goto out; } if (is_trusted_out != NULL) { *is_trusted_out = is_trusted; } out: talloc_free(mem_ctx); return ret; } /* Resign (and reform, including possibly new groups) a PAC */ static krb5_error_code samba_wdc_reget_pac(void *priv, astgs_request_t r, const krb5_principal _client_principal, const krb5_principal delegated_proxy_principal, hdb_entry *client, hdb_entry *server, hdb_entry *krbtgt, krb5_pac *pac) { krb5_context context = kdc_request_get_context((kdc_request_t)r); const hdb_entry *device = kdc_request_get_explicit_armor_client(r); const krb5_const_pac device_pac = kdc_request_get_explicit_armor_pac(r); struct samba_kdc_entry *client_skdc_entry = NULL; struct samba_kdc_entry *device_skdc_entry = NULL; const struct samba_kdc_entry *server_skdc_entry = talloc_get_type_abort(server->context, struct samba_kdc_entry); const struct samba_kdc_entry *krbtgt_skdc_entry = talloc_get_type_abort(krbtgt->context, struct samba_kdc_entry); TALLOC_CTX *mem_ctx = NULL; krb5_pac new_pac = NULL; krb5_error_code ret; uint32_t flags = 0; mem_ctx = talloc_named(NULL, 0, "samba_wdc_reget_pac context"); if (mem_ctx == NULL) { return ENOMEM; } if (client != NULL) { client_skdc_entry = talloc_get_type_abort(client->context, struct samba_kdc_entry); } if (device != NULL) { device_skdc_entry = talloc_get_type_abort(device->context, struct samba_kdc_entry); } ret = krb5_pac_init(context, &new_pac); if (ret != 0) { new_pac = NULL; goto out; } if (krb5_pac_is_trusted(*pac)) { flags |= SAMBA_KDC_FLAG_KRBTGT_IS_TRUSTED; } if (device_pac != NULL && krb5_pac_is_trusted(device_pac)) { flags |= SAMBA_KDC_FLAG_DEVICE_KRBTGT_IS_TRUSTED; } ret = samba_kdc_update_pac(mem_ctx, context, krbtgt_skdc_entry->kdc_db_ctx->samdb, flags, client_skdc_entry, server->principal, server_skdc_entry, delegated_proxy_principal, device_skdc_entry, device_pac, *pac, new_pac); if (ret != 0) { krb5_pac_free(context, new_pac); if (ret == ENOATTR) { krb5_pac_free(context, *pac); *pac = NULL; ret = 0; } goto out; } /* Replace the pac */ krb5_pac_free(context, *pac); *pac = new_pac; out: talloc_free(mem_ctx); return ret; } /* Verify a PAC's SID and signatures */ static krb5_error_code samba_wdc_verify_pac(void *priv, astgs_request_t r, const krb5_principal client_principal, const krb5_principal delegated_proxy_principal, hdb_entry *client, hdb_entry *server, hdb_entry *krbtgt, krb5_pac pac, krb5_boolean *is_trusted) { krb5_context context = kdc_request_get_context((kdc_request_t)r); krb5_kdc_configuration *config = kdc_request_get_config((kdc_request_t)r); struct samba_kdc_entry *krbtgt_skdc_entry = talloc_get_type_abort(krbtgt->context, struct samba_kdc_entry); krb5_error_code ret; krb5_cksumtype ctype = CKSUMTYPE_NONE; hdb_entry signing_krbtgt_hdb; const hdb_entry *explicit_armor_client = kdc_request_get_explicit_armor_client(r); krb5_const_pac explicit_armor_pac = kdc_request_get_explicit_armor_pac(r); if (delegated_proxy_principal) { uint16_t rodc_id; unsigned int my_krbtgt_number; /* * We're using delegated_proxy_principal for the moment to * indicate cases where the ticket was encrypted with the server * key, and not a krbtgt key. This cannot be trusted, so we need * to find a krbtgt key that signs the PAC in order to trust the * ticket. * * The krbtgt passed in to this function refers to the krbtgt * used to decrypt the ticket of the server requesting * S4U2Proxy. * * When we implement service ticket renewal, we need to check * the PAC, and this will need to be updated. */ ret = krb5_pac_get_kdc_checksum_info(context, pac, &ctype, &rodc_id); if (ret != 0) { DEBUG(1, ("Failed to get PAC checksum info\n")); return ret; } /* * We need to check the KDC and ticket signatures, fetching the * correct key based on the enctype. */ my_krbtgt_number = krbtgt_skdc_entry->kdc_db_ctx->my_krbtgt_number; if (my_krbtgt_number != 0) { /* * If we are an RODC, and we are not the KDC that signed * the evidence ticket, then we need to proxy the * request. */ if (rodc_id != my_krbtgt_number) { return HDB_ERR_NOT_FOUND_HERE; } } else { /* * If we are a DC, the ticket may have been signed by a * different KDC than the one that issued the header * ticket. */ if (rodc_id != krbtgt->kvno >> 16) { struct sdb_entry signing_krbtgt_sdb; /* * If we didn't sign the ticket, then return an * error. */ if (rodc_id != 0) { return KRB5KRB_AP_ERR_MODIFIED; } /* * Fetch our key from the database. To support * key rollover, we're going to need to try * multiple keys by trial and error. For now, * krbtgt keys aren't assumed to change. */ ret = samba_kdc_fetch(context, krbtgt_skdc_entry->kdc_db_ctx, krbtgt->principal, SDB_F_GET_KRBTGT | SDB_F_CANON, 0, &signing_krbtgt_sdb); if (ret != 0) { return ret; } ret = sdb_entry_to_hdb_entry(context, &signing_krbtgt_sdb, &signing_krbtgt_hdb); sdb_entry_free(&signing_krbtgt_sdb); if (ret != 0) { return ret; } /* * Replace the krbtgt entry with our own entry * for further processing. */ krbtgt = &signing_krbtgt_hdb; } } } else if (!krbtgt_skdc_entry->is_trust) { /* * We expect to have received a TGT, so check that we haven't * been given a kpasswd ticket instead. We don't need to do this * check for an incoming trust, as they use a different secret * and can't be confused with a normal TGT. */ krb5_ticket *tgt = kdc_request_get_ticket(r); struct timeval now = krb5_kdc_get_time(); /* * Check if the ticket is in the last two minutes of its * life. */ KerberosTime lifetime = rk_time_sub(tgt->ticket.endtime, now.tv_sec); if (lifetime <= CHANGEPW_LIFETIME) { /* * This ticket has at most two minutes left to live. It * may be a kpasswd ticket rather than a TGT, so don't * accept it. */ kdc_audit_addreason((kdc_request_t)r, "Ticket is not a ticket-granting ticket"); return KRB5KRB_AP_ERR_TKT_EXPIRED; } } ret = samba_wdc_verify_pac2(r, delegated_proxy_principal, client, server, krbtgt, pac, ctype, explicit_armor_client, &explicit_armor_pac, is_trusted); if (krbtgt == &signing_krbtgt_hdb) { hdb_free_entry(context, config->db[0], &signing_krbtgt_hdb); } return ret; } static char *get_netbios_name(TALLOC_CTX *mem_ctx, HostAddresses *addrs) { char *nb_name = NULL; size_t len; unsigned int i; for (i = 0; addrs && i < addrs->len; i++) { if (addrs->val[i].addr_type != KRB5_ADDRESS_NETBIOS) { continue; } len = MIN(addrs->val[i].address.length, 15); nb_name = talloc_strndup(mem_ctx, addrs->val[i].address.data, len); if (nb_name) { break; } } if ((nb_name == NULL) || (nb_name[0] == '\0')) { return NULL; } /* Strip space padding */ for (len = strlen(nb_name) - 1; (len > 0) && (nb_name[len] == ' '); --len) { nb_name[len] = '\0'; } return nb_name; } /* this function allocates 'data' using malloc. * The caller is responsible for freeing it */ static void samba_kdc_build_edata_reply(NTSTATUS nt_status, krb5_data *e_data) { e_data->data = malloc(12); if (e_data->data == NULL) { e_data->length = 0; e_data->data = NULL; return; } e_data->length = 12; SIVAL(e_data->data, 0, NT_STATUS_V(nt_status)); SIVAL(e_data->data, 4, 0); SIVAL(e_data->data, 8, 1); return; } static krb5_error_code samba_wdc_check_client_access(void *priv, astgs_request_t r) { struct samba_kdc_entry *kdc_entry; bool password_change; char *workstation; NTSTATUS nt_status; kdc_entry = talloc_get_type(kdc_request_get_client(r)->context, struct samba_kdc_entry); password_change = (kdc_request_get_server(r) && kdc_request_get_server(r)->flags.change_pw); workstation = get_netbios_name((TALLOC_CTX *)kdc_request_get_client(r)->context, kdc_request_get_req(r)->req_body.addresses); nt_status = samba_kdc_check_client_access(kdc_entry, kdc_request_get_cname((kdc_request_t)r), workstation, password_change); if (!NT_STATUS_IS_OK(nt_status)) { if (NT_STATUS_EQUAL(nt_status, NT_STATUS_NO_MEMORY)) { return ENOMEM; } if (kdc_request_get_rep(r)->padata) { int ret; krb5_data kd; samba_kdc_build_edata_reply(nt_status, &kd); ret = krb5_padata_add(kdc_request_get_context((kdc_request_t)r), kdc_request_get_rep(r)->padata, KRB5_PADATA_PW_SALT, kd.data, kd.length); if (ret != 0) { /* * So we do not leak the allocated * memory on kd in the error case */ krb5_data_free(&kd); } } return samba_kdc_map_policy_err(nt_status); } /* Now do the standard Heimdal check */ return KRB5_PLUGIN_NO_HANDLE; } /* this function allocates 'data' using malloc. * The caller is responsible for freeing it */ static krb5_error_code samba_kdc_build_supported_etypes(uint32_t supported_etypes, krb5_data *e_data) { e_data->data = malloc(4); if (e_data->data == NULL) { return ENOMEM; } e_data->length = 4; PUSH_LE_U32(e_data->data, 0, supported_etypes); return 0; } static krb5_error_code samba_wdc_finalize_reply(void *priv, astgs_request_t r) { struct samba_kdc_entry *server_kdc_entry; uint32_t supported_enctypes; server_kdc_entry = talloc_get_type(kdc_request_get_server(r)->context, struct samba_kdc_entry); /* * If the canonicalize flag is set, add PA-SUPPORTED-ENCTYPES padata * type to indicate what encryption types the server supports. */ supported_enctypes = server_kdc_entry->supported_enctypes; if (kdc_request_get_req(r)->req_body.kdc_options.canonicalize && supported_enctypes != 0) { krb5_error_code ret; PA_DATA md; ret = samba_kdc_build_supported_etypes(supported_enctypes, &md.padata_value); if (ret != 0) { return ret; } md.padata_type = KRB5_PADATA_SUPPORTED_ETYPES; ret = kdc_request_add_encrypted_padata(r, &md); if (ret != 0) { /* * So we do not leak the allocated * memory on kd in the error case */ krb5_data_free(&md.padata_value); } } return 0; } static krb5_error_code samba_wdc_plugin_init(krb5_context context, void **ptr) { *ptr = NULL; return 0; } static void samba_wdc_plugin_fini(void *ptr) { return; } static krb5_error_code samba_wdc_referral_policy(void *priv, astgs_request_t r) { return kdc_request_get_error_code((kdc_request_t)r); } struct krb5plugin_kdc_ftable kdc_plugin_table = { .minor_version = KRB5_PLUGIN_KDC_VERSION_11, .init = samba_wdc_plugin_init, .fini = samba_wdc_plugin_fini, .pac_verify = samba_wdc_verify_pac, .pac_update = samba_wdc_reget_pac, .client_access = samba_wdc_check_client_access, .finalize_reply = samba_wdc_finalize_reply, .pac_generate = samba_wdc_get_pac, .referral_policy = samba_wdc_referral_policy, };