diff options
Diffstat (limited to 'source4/kdc/kpasswd-service-mit.c')
| -rw-r--r-- | source4/kdc/kpasswd-service-mit.c | 400 |
1 files changed, 400 insertions, 0 deletions
diff --git a/source4/kdc/kpasswd-service-mit.c b/source4/kdc/kpasswd-service-mit.c new file mode 100644 index 0000000..053b1f2 --- /dev/null +++ b/source4/kdc/kpasswd-service-mit.c @@ -0,0 +1,400 @@ +/* + Unix SMB/CIFS implementation. + + Samba kpasswd implementation + + Copyright (c) 2016 Andreas Schneider <asn@samba.org> + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. +*/ + +#include "includes.h" +#include "samba/service_task.h" +#include "param/param.h" +#include "auth/auth.h" +#include "auth/gensec/gensec.h" +#include "gensec_krb5_helpers.h" +#include "kdc/kdc-server.h" +#include "kdc/kpasswd_glue.h" +#include "kdc/kpasswd-service.h" +#include "kdc/kpasswd-helper.h" +#include "../lib/util/asn1.h" + +#define RFC3244_VERSION 0xff80 + +krb5_error_code decode_krb5_setpw_req(const krb5_data *code, + krb5_data **password_out, + krb5_principal *target_out); + +/* + * A fallback for when MIT refuses to parse a setpw structure without the + * (optional) target principal and realm + */ +static bool decode_krb5_setpw_req_simple(TALLOC_CTX *mem_ctx, + const DATA_BLOB *decoded_data, + DATA_BLOB *clear_data) +{ + struct asn1_data *asn1 = NULL; + bool ret; + + asn1 = asn1_init(mem_ctx, 3); + if (asn1 == NULL) { + return false; + } + + ret = asn1_load(asn1, *decoded_data); + if (!ret) { + goto out; + } + + ret = asn1_start_tag(asn1, ASN1_SEQUENCE(0)); + if (!ret) { + goto out; + } + ret = asn1_start_tag(asn1, ASN1_CONTEXT(0)); + if (!ret) { + goto out; + } + ret = asn1_read_OctetString(asn1, mem_ctx, clear_data); + if (!ret) { + goto out; + } + + ret = asn1_end_tag(asn1); + if (!ret) { + goto out; + } + ret = asn1_end_tag(asn1); + +out: + asn1_free(asn1); + + return ret; +} + +static krb5_error_code kpasswd_change_password(struct kdc_server *kdc, + TALLOC_CTX *mem_ctx, + const struct gensec_security *gensec_security, + struct auth_session_info *session_info, + DATA_BLOB *password, + DATA_BLOB *kpasswd_reply, + const char **error_string) +{ + NTSTATUS status; + NTSTATUS result = NT_STATUS_UNSUCCESSFUL; + enum samPwdChangeReason reject_reason; + const char *reject_string = NULL; + struct samr_DomInfo1 *dominfo; + bool ok; + int ret; + + /* + * We're doing a password change (rather than a password set), so check + * that we were given an initial ticket. + */ + ret = gensec_krb5_initial_ticket(gensec_security); + if (ret != 1) { + *error_string = "Expected an initial ticket"; + return KRB5_KPASSWD_INITIAL_FLAG_NEEDED; + } + + status = samdb_kpasswd_change_password(mem_ctx, + kdc->task->lp_ctx, + kdc->task->event_ctx, + session_info, + password, + &reject_reason, + &dominfo, + &reject_string, + &result); + if (!NT_STATUS_IS_OK(status)) { + ok = kpasswd_make_error_reply(mem_ctx, + KRB5_KPASSWD_ACCESSDENIED, + reject_string, + kpasswd_reply); + if (!ok) { + *error_string = "Failed to create reply"; + return KRB5_KPASSWD_HARDERROR; + } + /* We want to send an an authenticated packet. */ + return 0; + } + + ok = kpasswd_make_pwchange_reply(mem_ctx, + result, + reject_reason, + dominfo, + kpasswd_reply); + if (!ok) { + *error_string = "Failed to create reply"; + return KRB5_KPASSWD_HARDERROR; + } + + return 0; +} + +static krb5_error_code kpasswd_set_password(struct kdc_server *kdc, + TALLOC_CTX *mem_ctx, + const struct gensec_security *gensec_security, + struct auth_session_info *session_info, + DATA_BLOB *decoded_data, + DATA_BLOB *kpasswd_reply, + const char **error_string) +{ + krb5_context context = kdc->smb_krb5_context->krb5_context; + DATA_BLOB clear_data; + krb5_data k_dec_data; + krb5_data *k_clear_data = NULL; + krb5_principal target_principal = NULL; + krb5_error_code code; + DATA_BLOB password; + char *target_realm = NULL; + char *target_name = NULL; + char *target_principal_string = NULL; + bool is_service_principal = false; + bool ok; + size_t num_components; + enum samPwdChangeReason reject_reason = SAM_PWD_CHANGE_NO_ERROR; + struct samr_DomInfo1 *dominfo = NULL; + NTSTATUS status; + + k_dec_data.length = decoded_data->length; + k_dec_data.data = (char *)decoded_data->data; + + code = decode_krb5_setpw_req(&k_dec_data, + &k_clear_data, + &target_principal); + if (code == 0) { + clear_data.data = (uint8_t *)k_clear_data->data; + clear_data.length = k_clear_data->length; + } else { + target_principal = NULL; + + /* + * The MIT decode failed, so fall back to trying the simple + * case, without target_principal. + */ + ok = decode_krb5_setpw_req_simple(mem_ctx, + decoded_data, + &clear_data); + if (!ok) { + DBG_WARNING("decode_krb5_setpw_req failed: %s\n", + error_message(code)); + ok = kpasswd_make_error_reply(mem_ctx, + KRB5_KPASSWD_MALFORMED, + "Failed to decode packet", + kpasswd_reply); + if (!ok) { + *error_string = "Failed to create reply"; + return KRB5_KPASSWD_HARDERROR; + } + return 0; + } + } + + ok = convert_string_talloc_handle(mem_ctx, + lpcfg_iconv_handle(kdc->task->lp_ctx), + CH_UTF8, + CH_UTF16, + clear_data.data, + clear_data.length, + (void **)&password.data, + &password.length); + if (k_clear_data != NULL) { + krb5_free_data(context, k_clear_data); + } + if (!ok) { + DBG_WARNING("String conversion failed\n"); + *error_string = "String conversion failed"; + return KRB5_KPASSWD_HARDERROR; + } + + if (target_principal != NULL) { + target_realm = smb_krb5_principal_get_realm( + mem_ctx, context, target_principal); + code = krb5_unparse_name_flags(context, + target_principal, + KRB5_PRINCIPAL_UNPARSE_NO_REALM, + &target_name); + if (code != 0) { + DBG_WARNING("Failed to parse principal\n"); + *error_string = "String conversion failed"; + return KRB5_KPASSWD_HARDERROR; + } + } + + if ((target_name != NULL && target_realm == NULL) || + (target_name == NULL && target_realm != NULL)) { + krb5_free_principal(context, target_principal); + TALLOC_FREE(target_realm); + SAFE_FREE(target_name); + + ok = kpasswd_make_error_reply(mem_ctx, + KRB5_KPASSWD_MALFORMED, + "Realm and principal must be " + "both present, or neither " + "present", + kpasswd_reply); + if (!ok) { + *error_string = "Failed to create reply"; + return KRB5_KPASSWD_HARDERROR; + } + return 0; + } + + if (target_name != NULL && target_realm != NULL) { + TALLOC_FREE(target_realm); + SAFE_FREE(target_name); + } else { + krb5_free_principal(context, target_principal); + TALLOC_FREE(target_realm); + SAFE_FREE(target_name); + + return kpasswd_change_password(kdc, + mem_ctx, + gensec_security, + session_info, + &password, + kpasswd_reply, + error_string); + } + + num_components = krb5_princ_size(context, target_principal); + if (num_components >= 2) { + is_service_principal = true; + code = krb5_unparse_name_flags(context, + target_principal, + KRB5_PRINCIPAL_UNPARSE_SHORT, + &target_principal_string); + } else { + code = krb5_unparse_name(context, + target_principal, + &target_principal_string); + } + krb5_free_principal(context, target_principal); + if (code != 0) { + ok = kpasswd_make_error_reply(mem_ctx, + KRB5_KPASSWD_MALFORMED, + "Failed to parse principal", + kpasswd_reply); + if (!ok) { + *error_string = "Failed to create reply"; + return KRB5_KPASSWD_HARDERROR; + } + } + + status = kpasswd_samdb_set_password(mem_ctx, + kdc->task->event_ctx, + kdc->task->lp_ctx, + session_info, + is_service_principal, + target_principal_string, + &password, + &reject_reason, + &dominfo); + if (!NT_STATUS_IS_OK(status)) { + DBG_ERR("kpasswd_samdb_set_password failed - %s\n", + nt_errstr(status)); + } + + ok = kpasswd_make_pwchange_reply(mem_ctx, + status, + reject_reason, + dominfo, + kpasswd_reply); + if (!ok) { + *error_string = "Failed to create reply"; + return KRB5_KPASSWD_HARDERROR; + } + + return 0; +} + +krb5_error_code kpasswd_handle_request(struct kdc_server *kdc, + TALLOC_CTX *mem_ctx, + struct gensec_security *gensec_security, + uint16_t verno, + DATA_BLOB *decoded_data, + DATA_BLOB *kpasswd_reply, + const char **error_string) +{ + struct auth_session_info *session_info; + NTSTATUS status; + krb5_error_code code; + + status = gensec_session_info(gensec_security, + mem_ctx, + &session_info); + if (!NT_STATUS_IS_OK(status)) { + *error_string = talloc_asprintf(mem_ctx, + "gensec_session_info failed - " + "%s", + nt_errstr(status)); + return KRB5_KPASSWD_HARDERROR; + } + + /* + * Since the kpasswd service shares its keys with the krbtgt, we might + * have received a TGT rather than a kpasswd ticket. We need to check + * the ticket type to ensure that TGTs cannot be misused in this manner. + */ + code = kpasswd_check_non_tgt(session_info, + error_string); + if (code != 0) { + DBG_WARNING("%s\n", *error_string); + return code; + } + + switch(verno) { + case 1: { + DATA_BLOB password; + bool ok; + + ok = convert_string_talloc_handle(mem_ctx, + lpcfg_iconv_handle(kdc->task->lp_ctx), + CH_UTF8, + CH_UTF16, + (const char *)decoded_data->data, + decoded_data->length, + (void **)&password.data, + &password.length); + if (!ok) { + *error_string = "String conversion failed!"; + DBG_WARNING("%s\n", *error_string); + return KRB5_KPASSWD_HARDERROR; + } + + return kpasswd_change_password(kdc, + mem_ctx, + gensec_security, + session_info, + &password, + kpasswd_reply, + error_string); + } + case RFC3244_VERSION: { + return kpasswd_set_password(kdc, + mem_ctx, + gensec_security, + session_info, + decoded_data, + kpasswd_reply, + error_string); + } + default: + return KRB5_KPASSWD_BAD_VERSION; + } + + return 0; +} |