/*
 * Copyright (c) 1997 - 2007 Kungliga Tekniska Högskolan
 * (Royal Institute of Technology, Stockholm, Sweden).
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. 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.
 *
 * 3. Neither the name of the Institute nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE 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 INSTITUTE 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 "krb5_locl.h"

static krb5_error_code
compare_addrs(krb5_context context,
              krb5_address *a,
              krb5_address *b,
              const char *message)
{
    char a_str[64], b_str[64];
    size_t len;

    if(krb5_address_compare (context, a, b))
        return 0;

    krb5_print_address (a, a_str, sizeof(a_str), &len);
    krb5_print_address (b, b_str, sizeof(b_str), &len);
    krb5_set_error_message(context, KRB5KRB_AP_ERR_BADADDR,
                           "%s: %s != %s", message, b_str, a_str);
    return KRB5KRB_AP_ERR_BADADDR;
}

KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_rd_cred(krb5_context context,
             krb5_auth_context auth_context,
             krb5_data *in_data,
             krb5_creds ***ret_creds,
             krb5_replay_data *outdata)
{
    krb5_error_code ret;
    size_t len;
    KRB_CRED cred;
    EncKrbCredPart enc_krb_cred_part;
    krb5_data enc_krb_cred_part_data;
    krb5_crypto crypto;
    size_t i;

    memset(&enc_krb_cred_part, 0, sizeof(enc_krb_cred_part));
    krb5_data_zero(&enc_krb_cred_part_data);

    if ((auth_context->flags &
         (KRB5_AUTH_CONTEXT_RET_TIME | KRB5_AUTH_CONTEXT_RET_SEQUENCE)) &&
        outdata == NULL)
        return KRB5_RC_REQUIRED; /* XXX better error, MIT returns this */

    *ret_creds = NULL;

    ret = decode_KRB_CRED(in_data->data, in_data->length,
                          &cred, &len);
    if(ret) {
        krb5_clear_error_message(context);
        return ret;
    }

    if (cred.pvno != 5) {
        ret = KRB5KRB_AP_ERR_BADVERSION;
        krb5_clear_error_message (context);
        goto out;
    }

    if (cred.msg_type != krb_cred) {
        ret = KRB5KRB_AP_ERR_MSG_TYPE;
        krb5_clear_error_message (context);
        goto out;
    }

    if (cred.enc_part.etype == ETYPE_NULL) {
        /* DK: MIT GSS-API Compatibility */
        enc_krb_cred_part_data.length = cred.enc_part.cipher.length;
        enc_krb_cred_part_data.data   = cred.enc_part.cipher.data;
    } else {
        /* Try both subkey and session key.
         *
         * RFC4120 claims we should use the session key, but Heimdal
         * before 0.8 used the remote subkey if it was send in the
         * auth_context.
         */

        if (auth_context->remote_subkey) {
            ret = krb5_crypto_init(context, auth_context->remote_subkey,
                                   0, &crypto);
            if (ret)
                goto out;

            ret = krb5_decrypt_EncryptedData(context,
                                             crypto,
                                             KRB5_KU_KRB_CRED,
                                             &cred.enc_part,
                                             &enc_krb_cred_part_data);

            krb5_crypto_destroy(context, crypto);
        }

        /*
         * If there was not subkey, or we failed using subkey,
         * retry using the session key
         */
        if (auth_context->remote_subkey == NULL || ret == KRB5KRB_AP_ERR_BAD_INTEGRITY)
        {

            ret = krb5_crypto_init(context, auth_context->keyblock,
                                   0, &crypto);

            if (ret)
                goto out;

            ret = krb5_decrypt_EncryptedData(context,
                                             crypto,
                                             KRB5_KU_KRB_CRED,
                                             &cred.enc_part,
                                             &enc_krb_cred_part_data);

            krb5_crypto_destroy(context, crypto);
        }
        if (ret)
            goto out;
    }

    ret = decode_EncKrbCredPart(enc_krb_cred_part_data.data,
                                enc_krb_cred_part_data.length,
                                &enc_krb_cred_part,
                                &len);
    if (enc_krb_cred_part_data.data != cred.enc_part.cipher.data)
        krb5_data_free(&enc_krb_cred_part_data);
    if (ret) {
        krb5_set_error_message(context, ret,
                               N_("Failed to decode "
                                  "encrypte credential part", ""));
        goto out;
    }

    /* check sender address */

    if (enc_krb_cred_part.s_address
        && auth_context->remote_address
        && auth_context->remote_port) {
        krb5_address *a;

        ret = krb5_make_addrport (context, &a,
                                  auth_context->remote_address,
                                  auth_context->remote_port);
        if (ret)
            goto out;


        ret = compare_addrs(context, a, enc_krb_cred_part.s_address,
                            N_("sender address is wrong "
                               "in received creds", ""));
        krb5_free_address(context, a);
        free(a);
        if(ret)
            goto out;
    }

    /* check receiver address */

    if (enc_krb_cred_part.r_address
        && auth_context->local_address) {
        if(auth_context->local_port &&
           enc_krb_cred_part.r_address->addr_type == KRB5_ADDRESS_ADDRPORT) {
            krb5_address *a;
            ret = krb5_make_addrport (context, &a,
                                      auth_context->local_address,
                                      auth_context->local_port);
            if (ret)
                goto out;

            ret = compare_addrs(context, a, enc_krb_cred_part.r_address,
                                N_("receiver address is wrong "
                                   "in received creds", ""));
            krb5_free_address(context, a);
            free(a);
            if(ret)
                goto out;
        } else {
            ret = compare_addrs(context, auth_context->local_address,
                                enc_krb_cred_part.r_address,
                                N_("receiver address is wrong "
                                   "in received creds", ""));
            if(ret)
                goto out;
        }
    }

    /* check timestamp */
    if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_TIME) {
        krb5_timestamp sec;

        krb5_timeofday (context, &sec);

        if (enc_krb_cred_part.timestamp == NULL ||
            enc_krb_cred_part.usec      == NULL ||
            abs(*enc_krb_cred_part.timestamp - sec)
            > context->max_skew) {
            krb5_clear_error_message (context);
            ret = KRB5KRB_AP_ERR_SKEW;
            goto out;
        }
    }

    if ((auth_context->flags &
         (KRB5_AUTH_CONTEXT_RET_TIME | KRB5_AUTH_CONTEXT_RET_SEQUENCE))) {
        /* if these fields are not present in the cred-part, silently
           return zero */
        memset(outdata, 0, sizeof(*outdata));
        if(enc_krb_cred_part.timestamp)
            outdata->timestamp = *enc_krb_cred_part.timestamp;
        if(enc_krb_cred_part.usec)
            outdata->usec = *enc_krb_cred_part.usec;
        if(enc_krb_cred_part.nonce)
            outdata->seq = *enc_krb_cred_part.nonce;
    }

    /* Convert to NULL terminated list of creds */

    *ret_creds = calloc(enc_krb_cred_part.ticket_info.len + 1,
                        sizeof(**ret_creds));

    if (*ret_creds == NULL) {
        ret = ENOMEM;
        krb5_set_error_message(context, ret,
                               N_("malloc: out of memory", ""));
        goto out;
    }

    for (i = 0; i < enc_krb_cred_part.ticket_info.len; ++i) {
        KrbCredInfo *kci = &enc_krb_cred_part.ticket_info.val[i];
        krb5_creds *creds;

        creds = calloc(1, sizeof(*creds));
        if(creds == NULL) {
            ret = ENOMEM;
            krb5_set_error_message(context, ret,
                                   N_("malloc: out of memory", ""));
            goto out;
        }

        ASN1_MALLOC_ENCODE(Ticket, creds->ticket.data, creds->ticket.length,
                           &cred.tickets.val[i], &len, ret);
        if (ret) {
            free(creds);
            goto out;
        }
        if(creds->ticket.length != len)
            krb5_abortx(context, "internal error in ASN.1 encoder");
        copy_EncryptionKey (&kci->key, &creds->session);
        if (kci->prealm && kci->pname)
            _krb5_principalname2krb5_principal (context,
                                                &creds->client,
                                                *kci->pname,
                                                *kci->prealm);
        if (kci->flags)
            creds->flags.b = *kci->flags;
        if (kci->authtime)
            creds->times.authtime = *kci->authtime;
        if (kci->starttime)
            creds->times.starttime = *kci->starttime;
        if (kci->endtime)
            creds->times.endtime = *kci->endtime;
        if (kci->renew_till)
            creds->times.renew_till = *kci->renew_till;
        if (kci->srealm && kci->sname)
            _krb5_principalname2krb5_principal (context,
                                                &creds->server,
                                                *kci->sname,
                                                *kci->srealm);
        if (kci->caddr)
            krb5_copy_addresses (context,
                                 kci->caddr,
                                 &creds->addresses);

        (*ret_creds)[i] = creds;

    }
    (*ret_creds)[i] = NULL;

    free_KRB_CRED (&cred);
    free_EncKrbCredPart(&enc_krb_cred_part);

    return 0;

  out:
    free_EncKrbCredPart(&enc_krb_cred_part);
    free_KRB_CRED (&cred);
    if(*ret_creds) {
        for(i = 0; (*ret_creds)[i]; i++)
            krb5_free_creds(context, (*ret_creds)[i]);
        free(*ret_creds);
        *ret_creds = NULL;
    }
    return ret;
}

KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_rd_cred2 (krb5_context      context,
               krb5_auth_context auth_context,
               krb5_ccache       ccache,
               krb5_data         *in_data)
{
    krb5_error_code ret;
    krb5_creds **creds;
    int i;

    ret = krb5_rd_cred(context, auth_context, in_data, &creds, NULL);
    if(ret)
        return ret;

    /* Store the creds in the ccache */

    for(i = 0; creds && creds[i]; i++) {
        krb5_cc_store_cred(context, ccache, creds[i]);
        krb5_free_creds(context, creds[i]);
    }
    free(creds);
    return 0;
}