/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */

/*

 * Copyright (C) 2011-2018 PADL Software Pty Ltd.

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 * * Redistributions of source code must retain the above copyright

 *   notice, this list of conditions and the following disclaimer.

 *

 * * Redistributions in binary form must reproduce the above copyright

 *   notice, this list of conditions and the following disclaimer in

 *   the documentation and/or other materials provided with the

 *   distribution.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS

 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE

 * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,

 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES

 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR

 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,

 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED

 * OF THE POSSIBILITY OF SUCH DAMAGE.

 */

#include "k5-int.h"

/*

 * { iso(1) identified-organization(3) dod(6) internet(1) private(4)

 *   enterprise(1) microsoft (311) security(2) mechanisms(2) negoex(30) }

 */

#define NEGOEX_OID_LENGTH 10

#define NEGOEX_OID "\x2b\x06\x01\x04\x01\x82\x37\x02\x02\x1e"

#define MESSAGE_SIGNATURE   0x535458454F47454EULL

#define EXTENSION_LENGTH                    12

#define EXTENSION_FLAG_CRITICAL             0x80000000

#define CHECKSUM_SCHEME_RFC3961             1

#define NEGOEX_KEYUSAGE_INITIATOR_CHECKSUM  23

#define NEGOEX_KEYUSAGE_ACCEPTOR_CHECKSUM   25

#define CHECKSUM_HEADER_LENGTH              20

#define GUID_LENGTH                         16

typedef uint8_t auth_scheme[GUID_LENGTH];

typedef uint8_t conversation_id[GUID_LENGTH];

#define GUID_EQ(a, b) (memcmp(a, b, GUID_LENGTH) == 0)

#define NEGO_MESSAGE_HEADER_LENGTH          96

#define EXCHANGE_MESSAGE_HEADER_LENGTH      64

#define VERIFY_MESSAGE_HEADER_LENGTH        80

#define ALERT_MESSAGE_HEADER_LENGTH         72

#define ALERT_LENGTH                        12

#define ALERT_PULSE_LENGTH                  8

#define ALERT_TYPE_PULSE                    1

#define ALERT_VERIFY_NO_KEY                 1

enum message_type {

    INITIATOR_NEGO = 0,         /* NEGO_MESSAGE */

    ACCEPTOR_NEGO,              /* NEGO_MESSAGE */

    INITIATOR_META_DATA,        /* EXCHANGE_MESSAGE */

    ACCEPTOR_META_DATA,         /* EXCHANGE_MESSAGE */

    CHALLENGE,                  /* EXCHANGE_MESSAGE */

    AP_REQUEST,                 /* EXCHANGE_MESSAGE */

    VERIFY,                     /* VERIFY_MESSAGE */

    ALERT,                      /* ALERT */

};

struct nego_message {

    uint8_t random[32];

    const uint8_t *schemes;

    uint16_t nschemes;

};

struct exchange_message {

    auth_scheme scheme;

    gss_buffer_desc token;

};

struct verify_message {

    auth_scheme scheme;

    uint32_t cksum_type;

    const uint8_t *cksum;

    size_t cksum_len;

    size_t offset_in_token;

};

struct alert_message {

    auth_scheme scheme;

    int verify_no_key;

};

struct negoex_message {

    uint32_t type;

    union {

        struct nego_message n;

        struct exchange_message e;

        struct verify_message v;

        struct alert_message a;

    } u;

};

struct negoex_auth_mech {

    K5_TAILQ_ENTRY(negoex_auth_mech) links;

    gss_OID oid;

    auth_scheme scheme;

    gss_ctx_id_t mech_context;

    gss_buffer_desc metadata;

    krb5_keyblock key;

    krb5_keyblock verify_key;

    int complete;

    int sent_checksum;

    int verified_checksum;

};

/* negoex_util.c */

OM_uint32

negoex_parse_token(OM_uint32 *minor, spnego_gss_ctx_id_t ctx,

                   gss_const_buffer_t token,

                   struct negoex_message **messages_out, size_t *count_out);

struct nego_message *

negoex_locate_nego_message(struct negoex_message *messages, size_t nmessages,

                           enum message_type type);

struct exchange_message *

negoex_locate_exchange_message(struct negoex_message *messages,

                               size_t nmessages, enum message_type type);

struct verify_message *

negoex_locate_verify_message(struct negoex_message *messages,

                             size_t nmessages);

struct alert_message *

negoex_locate_alert_message(struct negoex_message *messages, size_t nmessages);

void

negoex_add_nego_message(spnego_gss_ctx_id_t ctx, enum message_type type,

                        uint8_t random[32]);

void

negoex_add_exchange_message(spnego_gss_ctx_id_t ctx, enum message_type type,

                            const auth_scheme scheme, gss_buffer_t token);

void

negoex_add_verify_message(spnego_gss_ctx_id_t ctx, const auth_scheme scheme,

                          uint32_t cksum_type, const uint8_t *cksum,

                          uint32_t cksum_len);

void

negoex_add_verify_no_key_alert(spnego_gss_ctx_id_t ctx,

                               const auth_scheme scheme);

OM_uint32

negoex_random(OM_uint32 *minor, spnego_gss_ctx_id_t ctx,

              unsigned char *data, size_t length);

void

negoex_prep_context_for_spnego(spnego_gss_ctx_id_t ctx);

OM_uint32

negoex_prep_context_for_negoex(OM_uint32 *minor, spnego_gss_ctx_id_t ctx);

void

negoex_release_context(spnego_gss_ctx_id_t ctx);

OM_uint32

negoex_add_auth_mech(OM_uint32 *minor, spnego_gss_ctx_id_t ctx,

                     gss_const_OID oid, auth_scheme scheme);

void

negoex_delete_auth_mech(spnego_gss_ctx_id_t ctx,

                        struct negoex_auth_mech *mech);

void

negoex_select_auth_mech(spnego_gss_ctx_id_t ctx,

                        struct negoex_auth_mech *mech);

struct negoex_auth_mech *

negoex_locate_auth_scheme(spnego_gss_ctx_id_t ctx, const auth_scheme scheme);

void

negoex_common_auth_schemes(spnego_gss_ctx_id_t ctx,

                           const uint8_t *schemes, uint16_t nschemes);

void

negoex_restrict_auth_schemes(spnego_gss_ctx_id_t ctx,

                             const uint8_t *schemes, uint16_t nschemes);

/* negoex_ctx.c */

OM_uint32

negoex_init(OM_uint32 *minor, spnego_gss_ctx_id_t ctx, gss_cred_id_t cred,

            gss_name_t target_name, OM_uint32 req_flags, OM_uint32 time_req,

            gss_buffer_t input_token, gss_buffer_t output_token,

            OM_uint32 *time_rec);

OM_uint32

negoex_accept(OM_uint32 *minor, spnego_gss_ctx_id_t ctx, gss_cred_id_t cred,

              gss_buffer_t input_token, gss_buffer_t output_token,

              OM_uint32 *time_rec);