source: vendor/current/auth/gensec/gensec_util.c

/*
   Unix SMB/CIFS implementation.

   Generic Authentication Interface

   Copyright (C) Andrew Tridgell 2003
   Copyright (C) Andrew Bartlett <abartlet@samba.org> 2004-2006

   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 "auth/gensec/gensec.h"
#include "auth/gensec/gensec_internal.h"
#include "auth/common_auth.h"
#include "../lib/util/asn1.h"

NTSTATUS gensec_generate_session_info_pac(TALLOC_CTX *mem_ctx,
                                          struct gensec_security *gensec_security,
                                          struct smb_krb5_context *smb_krb5_context,
                                          DATA_BLOB *pac_blob,
                                          const char *principal_string,
                                          const struct tsocket_address *remote_address,
                                          struct auth_session_info **session_info)
{
        uint32_t session_info_flags = 0;

        if (gensec_security->want_features & GENSEC_FEATURE_UNIX_TOKEN) {
                session_info_flags |= AUTH_SESSION_INFO_UNIX_TOKEN;
        }

        session_info_flags |= AUTH_SESSION_INFO_DEFAULT_GROUPS;

        if (!pac_blob) {
                if (gensec_setting_bool(gensec_security->settings, "gensec", "require_pac", false)) {
                        DEBUG(1, ("Unable to find PAC in ticket from %s, failing to allow access\n",
                                  principal_string));
                        return NT_STATUS_ACCESS_DENIED;
                }
                DEBUG(1, ("Unable to find PAC for %s, resorting to local user lookup\n",
                          principal_string));
        }

        if (gensec_security->auth_context && gensec_security->auth_context->generate_session_info_pac) {
                return gensec_security->auth_context->generate_session_info_pac(gensec_security->auth_context,
                                                                                mem_ctx,
                                                                                smb_krb5_context,
                                                                                pac_blob,
                                                                                principal_string,
                                                                                remote_address,
                                                                                session_info_flags,
                                                                                session_info);
        } else {
                DEBUG(0, ("Cannot generate a session_info without the auth_context\n"));
                return NT_STATUS_INTERNAL_ERROR;
        }
}

/*
  magic check a GSS-API wrapper packet for an Kerberos OID
*/
static bool gensec_gssapi_check_oid(const DATA_BLOB *blob, const char *oid)
{
        bool ret = false;
        struct asn1_data *data = asn1_init(NULL);

        if (!data) return false;

        if (!asn1_load(data, *blob)) goto err;
        if (!asn1_start_tag(data, ASN1_APPLICATION(0))) goto err;
        if (!asn1_check_OID(data, oid)) goto err;

        ret = !asn1_has_error(data);

  err:

        asn1_free(data);
        return ret;
}

/**
 * Check if the packet is one for the KRB5 mechansim
 *
 * NOTE: This is a helper that can be employed by multiple mechanisms, do
 * not make assumptions about the private_data
 *
 * @param gensec_security GENSEC state, unused
 * @param in The request, as a DATA_BLOB
 * @return Error, INVALID_PARAMETER if it's not a packet for us
 *                or NT_STATUS_OK if the packet is ok.
 */

NTSTATUS gensec_magic_check_krb5_oid(struct gensec_security *unused,
                                        const DATA_BLOB *blob)
{
        if (gensec_gssapi_check_oid(blob, GENSEC_OID_KERBEROS5)) {
                return NT_STATUS_OK;
        } else {
                return NT_STATUS_INVALID_PARAMETER;
        }
}