/* Unix SMB/CIFS implementation. kpasswd Server implementation Copyright (C) Andrew Bartlett <abartlet@samba.org> 2005 Copyright (C) Andrew Tridgell 2005 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 2 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, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #include "includes.h" #include "smbd/service_task.h" #include "lib/events/events.h" #include "lib/socket/socket.h" #include "kdc/kdc.h" #include "system/network.h" #include "dlinklist.h" #include "lib/ldb/include/ldb.h" #include "heimdal/lib/krb5/krb5-private.h" #include "auth/auth.h" #include "dsdb/samdb/samdb.h" /* hold information about one kdc socket */ struct kpasswd_socket { struct socket_context *sock; struct kdc_server *kdc; struct fd_event *fde; /* a queue of outgoing replies that have been deferred */ struct kdc_reply *send_queue; }; /* Return true if there is a valid error packet formed in the error_blob */ static BOOL kpasswdd_make_error_reply(struct kdc_server *kdc, TALLOC_CTX *mem_ctx, uint16_t result_code, const char *error_string, DATA_BLOB *error_blob) { char *error_string_utf8; ssize_t len; DEBUG(result_code ? 3 : 10, ("kpasswdd: %s\n", error_string)); len = push_utf8_talloc(mem_ctx, &error_string_utf8, error_string); if (len == -1) { return False; } *error_blob = data_blob_talloc(mem_ctx, NULL, 2 + len + 1); if (!error_blob->data) { return False; } RSSVAL(error_blob->data, 0, result_code); memcpy(error_blob->data + 2, error_string_utf8, len + 1); return True; } /* Return true if there is a valid error packet formed in the error_blob */ static BOOL kpasswdd_make_unauth_error_reply(struct kdc_server *kdc, TALLOC_CTX *mem_ctx, uint16_t result_code, const char *error_string, DATA_BLOB *error_blob) { BOOL ret; int kret; DATA_BLOB error_bytes; krb5_data k5_error_bytes, k5_error_blob; ret = kpasswdd_make_error_reply(kdc, mem_ctx, result_code, error_string, &error_bytes); if (!ret) { return False; } k5_error_bytes.data = error_bytes.data; k5_error_bytes.length = error_bytes.length; kret = krb5_mk_error(kdc->smb_krb5_context->krb5_context, result_code, NULL, &k5_error_bytes, NULL, NULL, NULL, NULL, &k5_error_blob); if (kret) { return False; } *error_blob = data_blob_talloc(mem_ctx, k5_error_blob.data, k5_error_blob.length); krb5_data_free(&k5_error_blob); if (!error_blob->data) { return False; } return True; } static BOOL kpasswd_make_pwchange_reply(struct kdc_server *kdc, TALLOC_CTX *mem_ctx, NTSTATUS status, enum samr_RejectReason reject_reason, struct samr_DomInfo1 *dominfo, DATA_BLOB *error_blob) { if (NT_STATUS_EQUAL(status, NT_STATUS_NO_SUCH_USER)) { return kpasswdd_make_error_reply(kdc, mem_ctx, KRB5_KPASSWD_ACCESSDENIED, "No such user when changing password", error_blob); } if (NT_STATUS_EQUAL(status, NT_STATUS_ACCESS_DENIED)) { return kpasswdd_make_error_reply(kdc, mem_ctx, KRB5_KPASSWD_ACCESSDENIED, "Not permitted to change password", error_blob); } if (NT_STATUS_EQUAL(status, NT_STATUS_PASSWORD_RESTRICTION)) { const char *reject_string; switch (reject_reason) { case SAMR_REJECT_TOO_SHORT: reject_string = talloc_asprintf(mem_ctx, "Password too short, password must be at least %d characters long", dominfo->min_password_length); break; case SAMR_REJECT_COMPLEXITY: reject_string = "Password does not meet complexity requirements"; break; case SAMR_REJECT_OTHER: default: reject_string = talloc_asprintf(mem_ctx, "Password must be at least %d characters long, and cannot match any of your %d previous passwords", dominfo->min_password_length, dominfo->password_history_length); break; } return kpasswdd_make_error_reply(kdc, mem_ctx, KRB5_KPASSWD_SOFTERROR, reject_string, error_blob); } if (!NT_STATUS_IS_OK(status)) { return kpasswdd_make_error_reply(kdc, mem_ctx, KRB5_KPASSWD_HARDERROR, talloc_asprintf(mem_ctx, "failed to set password: %s", nt_errstr(status)), error_blob); } return kpasswdd_make_error_reply(kdc, mem_ctx, KRB5_KPASSWD_SUCCESS, "Password changed", error_blob); } /* A user password change Return true if there is a valid error packet (or sucess) formed in the error_blob */ static BOOL kpasswdd_change_password(struct kdc_server *kdc, TALLOC_CTX *mem_ctx, struct auth_session_info *session_info, const char *password, DATA_BLOB *reply) { NTSTATUS status; enum samr_RejectReason reject_reason; struct samr_DomInfo1 *dominfo; struct ldb_context *samdb; samdb = samdb_connect(mem_ctx, system_session(mem_ctx)); if (!samdb) { return kpasswdd_make_error_reply(kdc, mem_ctx, KRB5_KPASSWD_HARDERROR, "Failed to open samdb", reply); } DEBUG(3, ("Changing password of %s\\%s (%s)\n", session_info->server_info->domain_name, session_info->server_info->account_name, dom_sid_string(mem_ctx, session_info->security_token->user_sid))); /* User password change */ status = samdb_set_password_sid(samdb, mem_ctx, session_info->security_token->user_sid, password, NULL, NULL, True, /* this is a user password change */ True, /* run restriction tests */ &reject_reason, &dominfo); return kpasswd_make_pwchange_reply(kdc, mem_ctx, status, reject_reason, dominfo, reply); } static BOOL kpasswd_process_request(struct kdc_server *kdc, TALLOC_CTX *mem_ctx, struct gensec_security *gensec_security, uint16_t version, DATA_BLOB *input, DATA_BLOB *reply) { struct auth_session_info *session_info; if (!NT_STATUS_IS_OK(gensec_session_info(gensec_security, &session_info))) { return kpasswdd_make_error_reply(kdc, mem_ctx, KRB5_KPASSWD_HARDERROR, "gensec_session_info failed!", reply); } switch (version) { case KRB5_KPASSWD_VERS_CHANGEPW: { char *password = talloc_strndup(mem_ctx, (const char *)input->data, input->length); if (!password) { return False; } return kpasswdd_change_password(kdc, mem_ctx, session_info, password, reply); break; } case KRB5_KPASSWD_VERS_SETPW: { NTSTATUS status; enum samr_RejectReason reject_reason; struct samr_DomInfo1 *dominfo; struct ldb_context *samdb; struct ldb_message *msg; krb5_context context = kdc->smb_krb5_context->krb5_context; ChangePasswdDataMS chpw; char *password; krb5_principal principal; char *set_password_on_princ; struct ldb_dn *set_password_on_dn; size_t len; int ret; msg = ldb_msg_new(mem_ctx); if (!msg) { return False; } ret = decode_ChangePasswdDataMS(input->data, input->length, &chpw, &len); if (ret) { return kpasswdd_make_error_reply(kdc, mem_ctx, KRB5_KPASSWD_MALFORMED, "failed to decode password change structure", reply); } password = talloc_strndup(mem_ctx, chpw.newpasswd.data, chpw.newpasswd.length); if (!password) { free_ChangePasswdDataMS(&chpw); return False; } if ((chpw.targname && !chpw.targrealm) || (!chpw.targname && chpw.targrealm)) { return kpasswdd_make_error_reply(kdc, mem_ctx, KRB5_KPASSWD_MALFORMED, "Realm and principal must be both present, or neither present", reply); } if (chpw.targname && chpw.targrealm) { if (_krb5_principalname2krb5_principal(&principal, *chpw.targname, *chpw.targrealm) != 0) { free_ChangePasswdDataMS(&chpw); return kpasswdd_make_error_reply(kdc, mem_ctx, KRB5_KPASSWD_MALFORMED, "failed to extract principal to set", reply); } } else { free_ChangePasswdDataMS(&chpw); return kpasswdd_change_password(kdc, mem_ctx, session_info, password, reply); } free_ChangePasswdDataMS(&chpw); if (krb5_unparse_name(context, principal, &set_password_on_princ) != 0) { krb5_free_principal(context, principal); return kpasswdd_make_error_reply(kdc, mem_ctx, KRB5_KPASSWD_MALFORMED, "krb5_unparse_name failed!", reply); } krb5_free_principal(context, principal); samdb = samdb_connect(mem_ctx, session_info); if (!samdb) { return kpasswdd_make_error_reply(kdc, mem_ctx, KRB5_KPASSWD_HARDERROR, "Unable to open database!", reply); } DEBUG(3, ("%s\\%s (%s) is changing password of %s\n", session_info->server_info->domain_name, session_info->server_info->account_name, dom_sid_string(mem_ctx, session_info->security_token->user_sid), set_password_on_princ)); ret = ldb_transaction_start(samdb); if (ret) { status = NT_STATUS_TRANSACTION_ABORTED; return kpasswd_make_pwchange_reply(kdc, mem_ctx, status, reject_reason, dominfo, reply); } status = crack_user_principal_name(samdb, mem_ctx, set_password_on_princ, &set_password_on_dn, NULL); free(set_password_on_princ); if (!NT_STATUS_IS_OK(status)) { ldb_transaction_cancel(samdb); return kpasswd_make_pwchange_reply(kdc, mem_ctx, status, reject_reason, dominfo, reply); } msg = ldb_msg_new(mem_ctx); if (msg == NULL) { ldb_transaction_cancel(samdb); status = NT_STATUS_NO_MEMORY; } else { msg->dn = ldb_dn_copy(msg, set_password_on_dn); if (!msg->dn) { status = NT_STATUS_NO_MEMORY; } } if (NT_STATUS_IS_OK(status)) { /* Admin password set */ status = samdb_set_password(samdb, mem_ctx, set_password_on_dn, NULL, msg, password, NULL, NULL, False, /* this is not a user password change */ True, /* run restriction tests */ &reject_reason, &dominfo); } if (NT_STATUS_IS_OK(status)) { /* modify the samdb record */ ret = samdb_replace(samdb, mem_ctx, msg); if (ret != 0) { DEBUG(2,("Failed to modify record to set password on %s: %s\n", ldb_dn_linearize(mem_ctx, msg->dn), ldb_errstring(samdb))); status = NT_STATUS_ACCESS_DENIED; } } if (NT_STATUS_IS_OK(status)) { ret = ldb_transaction_commit(samdb); if (ret != 0) { DEBUG(1,("Failed to commit transaction to set password on %s: %s\n", ldb_dn_linearize(mem_ctx, msg->dn), ldb_errstring(samdb))); status = NT_STATUS_TRANSACTION_ABORTED; } } else { ldb_transaction_cancel(samdb); } return kpasswd_make_pwchange_reply(kdc, mem_ctx, status, reject_reason, dominfo, reply); } default: return kpasswdd_make_error_reply(kdc, mem_ctx, KRB5_KPASSWD_BAD_VERSION, talloc_asprintf(mem_ctx, "Protocol version %u not supported", version), reply); } return True; } BOOL kpasswdd_process(struct kdc_server *kdc, TALLOC_CTX *mem_ctx, DATA_BLOB *input, DATA_BLOB *reply, struct socket_address *peer_addr, struct socket_address *my_addr) { BOOL ret; const uint16_t header_len = 6; uint16_t len; uint16_t ap_req_len; uint16_t krb_priv_len; uint16_t version; NTSTATUS nt_status; DATA_BLOB ap_req, krb_priv_req, krb_priv_rep, ap_rep; DATA_BLOB kpasswd_req, kpasswd_rep; struct cli_credentials *server_credentials; struct gensec_security *gensec_security; TALLOC_CTX *tmp_ctx = talloc_new(mem_ctx); if (!tmp_ctx) { return False; } /* Be parinoid. We need to ensure we don't just let the * caller lead us into a buffer overflow */ if (input->length <= header_len) { talloc_free(tmp_ctx); return False; } len = RSVAL(input->data, 0); if (input->length != len) { talloc_free(tmp_ctx); return False; } /* There are two different versions of this protocol so far, * plus others in the standards pipe. Fortunetly they all * take a very similar framing */ version = RSVAL(input->data, 2); ap_req_len = RSVAL(input->data, 4); if ((ap_req_len >= len) || (ap_req_len + header_len) >= len) { talloc_free(tmp_ctx); return False; } krb_priv_len = len - ap_req_len; ap_req = data_blob_const(&input->data[header_len], ap_req_len); krb_priv_req = data_blob_const(&input->data[header_len + ap_req_len], krb_priv_len); nt_status = gensec_server_start(tmp_ctx, &gensec_security, kdc->task->event_ctx); if (!NT_STATUS_IS_OK(nt_status)) { talloc_free(tmp_ctx); return False; } server_credentials = cli_credentials_init(tmp_ctx); if (!server_credentials) { DEBUG(1, ("Failed to init server credentials\n")); return False; } /* We want the credentials subsystem to use the krb5 context * we already have, rather than a new context */ cli_credentials_set_krb5_context(server_credentials, kdc->smb_krb5_context); cli_credentials_set_conf(server_credentials); nt_status = cli_credentials_set_stored_principal(server_credentials, "kadmin/changepw"); if (!NT_STATUS_IS_OK(nt_status)) { ret = kpasswdd_make_unauth_error_reply(kdc, mem_ctx, KRB5_KPASSWD_HARDERROR, talloc_asprintf(mem_ctx, "Failed to obtain server credentials for kadmin/changepw: %s\n", nt_errstr(nt_status)), &krb_priv_rep); ap_rep.length = 0; if (ret) { goto reply; } talloc_free(tmp_ctx); return ret; } nt_status = gensec_set_credentials(gensec_security, server_credentials); if (!NT_STATUS_IS_OK(nt_status)) { talloc_free(tmp_ctx); return False; } /* The kerberos PRIV packets include these addresses. MIT * clients check that they are present */ nt_status = gensec_set_peer_addr(gensec_security, peer_addr); if (!NT_STATUS_IS_OK(nt_status)) { talloc_free(tmp_ctx); return False; } nt_status = gensec_set_my_addr(gensec_security, my_addr); if (!NT_STATUS_IS_OK(nt_status)) { talloc_free(tmp_ctx); return False; } /* We want the GENSEC wrap calls to generate PRIV tokens */ gensec_want_feature(gensec_security, GENSEC_FEATURE_SEAL); nt_status = gensec_start_mech_by_name(gensec_security, "krb5"); if (!NT_STATUS_IS_OK(nt_status)) { talloc_free(tmp_ctx); return False; } /* Accept the AP-REQ and generate teh AP-REP we need for the reply */ nt_status = gensec_update(gensec_security, tmp_ctx, ap_req, &ap_rep); if (!NT_STATUS_IS_OK(nt_status) && !NT_STATUS_EQUAL(nt_status, NT_STATUS_MORE_PROCESSING_REQUIRED)) { ret = kpasswdd_make_unauth_error_reply(kdc, mem_ctx, KRB5_KPASSWD_HARDERROR, talloc_asprintf(mem_ctx, "gensec_update failed: %s", nt_errstr(nt_status)), &krb_priv_rep); ap_rep.length = 0; if (ret) { goto reply; } talloc_free(tmp_ctx); return ret; } /* Extract the data from the KRB-PRIV half of the message */ nt_status = gensec_unwrap(gensec_security, tmp_ctx, &krb_priv_req, &kpasswd_req); if (!NT_STATUS_IS_OK(nt_status)) { ret = kpasswdd_make_unauth_error_reply(kdc, mem_ctx, KRB5_KPASSWD_HARDERROR, talloc_asprintf(mem_ctx, "gensec_unwrap failed: %s", nt_errstr(nt_status)), &krb_priv_rep); ap_rep.length = 0; if (ret) { goto reply; } talloc_free(tmp_ctx); return ret; } /* Figure out something to do with it (probably changing a password...) */ ret = kpasswd_process_request(kdc, tmp_ctx, gensec_security, version, &kpasswd_req, &kpasswd_rep); if (!ret) { /* Argh! */ return False; } /* And wrap up the reply: This ensures that the error message * or success can be verified by the client */ nt_status = gensec_wrap(gensec_security, tmp_ctx, &kpasswd_rep, &krb_priv_rep); if (!NT_STATUS_IS_OK(nt_status)) { ret = kpasswdd_make_unauth_error_reply(kdc, mem_ctx, KRB5_KPASSWD_HARDERROR, talloc_asprintf(mem_ctx, "gensec_wrap failed: %s", nt_errstr(nt_status)), &krb_priv_rep); ap_rep.length = 0; if (ret) { goto reply; } talloc_free(tmp_ctx); return ret; } reply: *reply = data_blob_talloc(mem_ctx, NULL, krb_priv_rep.length + ap_rep.length + header_len); if (!reply->data) { return False; } RSSVAL(reply->data, 0, reply->length); RSSVAL(reply->data, 2, 1); /* This is a version 1 reply, MS change/set or otherwise */ RSSVAL(reply->data, 4, ap_rep.length); memcpy(reply->data + header_len, ap_rep.data, ap_rep.length); memcpy(reply->data + header_len + ap_rep.length, krb_priv_rep.data, krb_priv_rep.length); talloc_free(tmp_ctx); return ret; }