diff options
Diffstat (limited to 'source4/kdc/kpasswdd.c')
| -rw-r--r-- | source4/kdc/kpasswdd.c | 614 |
1 files changed, 614 insertions, 0 deletions
diff --git a/source4/kdc/kpasswdd.c b/source4/kdc/kpasswdd.c new file mode 100644 index 0000000000..603332e69e --- /dev/null +++ b/source4/kdc/kpasswdd.c @@ -0,0 +1,614 @@ +/* + 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 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 "smbd/service_task.h" +#include "lib/events/events.h" +#include "lib/socket/socket.h" +#include "system/network.h" +#include "lib/util/dlinklist.h" +#include "lib/ldb/include/ldb.h" +#include "auth/gensec/gensec.h" +#include "auth/credentials/credentials.h" +#include "auth/credentials/credentials_krb5.h" +#include "auth/auth.h" +#include "dsdb/samdb/samdb.h" +#include "rpc_server/dcerpc_server.h" +#include "rpc_server/samr/proto.h" +#include "libcli/security/security.h" +#include "param/param.h" +#include "kdc/kdc.h" + +/* TODO: remove all SAMBA4_INTERNAL_HEIMDAL stuff from this file */ +#ifdef SAMBA4_INTERNAL_HEIMDAL +#include "heimdal_build/kpasswdd-glue.h" +#endif + +/* 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, lp_iconv_convenience(kdc->task->lp_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 (dominfo && 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_IN_HISTORY: + reject_string = "Password is already in password history"; + 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, kdc->task->event_ctx, kdc->task->lp_ctx, system_session(mem_ctx, kdc->task->lp_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 */ + &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 = SAMR_REJECT_OTHER; + struct samr_DomInfo1 *dominfo = NULL; + 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, + (const char *)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) { +#ifdef SAMBA4_INTERNAL_HEIMDAL + if (_krb5_principalname2krb5_principal(kdc->smb_krb5_context->krb5_context, + &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 /* SAMBA4_INTERNAL_HEIMDAL */ + return kpasswdd_make_error_reply(kdc, mem_ctx, + KRB5_KPASSWD_BAD_VERSION, + "Operation Not Implemented", + reply); +#endif /* SAMBA4_INTERNAL_HEIMDAL */ + } 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, kdc->task->event_ctx, kdc->task->lp_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, + SAMR_REJECT_OTHER, + NULL, + 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, + SAMR_REJECT_OTHER, + NULL, + 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 */ + &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_get_linearized(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_get_linearized(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, + int datagram_reply) +{ + 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; + DATA_BLOB krb_priv_rep = data_blob(NULL, 0); + DATA_BLOB ap_rep = data_blob(NULL, 0); + 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, kdc->task->event_ctx, kdc->task->lp_ctx, kdc->task->msg_ctx, &gensec_security); + 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, kdc->task->lp_ctx); + nt_status = cli_credentials_set_stored_principal(server_credentials, kdc->task->event_ctx, kdc->task->lp_ctx, "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; +} + |