/*
 * 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"

/*
 * See `sendauth.c' for the format.
 */

static krb5_boolean
match_exact(const void *data, const char *appl_version)
{
    return strcmp(data, appl_version) == 0;
}

KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_recvauth(krb5_context context,
              krb5_auth_context *auth_context,
              krb5_pointer p_fd,
              const char *appl_version,
              krb5_principal server,
              int32_t flags,
              krb5_keytab keytab,
              krb5_ticket **ticket)
{
    return krb5_recvauth_match_version(context, auth_context, p_fd,
                                       match_exact, appl_version,
                                       server, flags,
                                       keytab, ticket);
}

KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_recvauth_match_version(krb5_context context,
                            krb5_auth_context *auth_context,
                            krb5_pointer p_fd,
                            krb5_boolean (*match_appl_version)(const void *,
                                                               const char*),
                            const void *match_data,
                            krb5_principal server,
                            int32_t flags,
                            krb5_keytab keytab,
                            krb5_ticket **ticket)
{
    krb5_error_code ret;
    const char *version = KRB5_SENDAUTH_VERSION;
    char her_version[sizeof(KRB5_SENDAUTH_VERSION)];
    char *her_appl_version;
    uint32_t len, bytes;
    u_char repl;
    krb5_data data;
    krb5_flags ap_options;
    ssize_t n;

    /*
     * If there are no addresses in auth_context, get them from `fd'.
     */

    if (*auth_context == NULL) {
        ret = krb5_auth_con_init (context, auth_context);
        if (ret)
            return ret;
    }

    ret = krb5_auth_con_setaddrs_from_fd (context,
                                          *auth_context,
                                          p_fd);
    if (ret)
        return ret;

    if(!(flags & KRB5_RECVAUTH_IGNORE_VERSION)) {
        n = krb5_net_read (context, p_fd, &len, 4);
        if (n < 0) {
            ret = errno;
            krb5_set_error_message(context, ret, "read: %s", strerror(ret));
            return ret;
        }
        if (n == 0) {
            krb5_set_error_message(context, KRB5_SENDAUTH_BADAUTHVERS,
                                   N_("Failed to receive sendauth data", ""));
            return KRB5_SENDAUTH_BADAUTHVERS;
        }
        len = ntohl(len);
        if (len != sizeof(her_version)
            || krb5_net_read (context, p_fd, her_version, len) != len
            || strncmp (version, her_version, len)) {
            repl = 1;
            krb5_net_write (context, p_fd, &repl, 1);
            krb5_clear_error_message (context);
            return KRB5_SENDAUTH_BADAUTHVERS;
        }
    }

    n = krb5_net_read (context, p_fd, &len, 4);
    if (n < 0) {
        ret = errno;
        krb5_set_error_message(context, ret, "read: %s", strerror(ret));
        return ret;
    }
    if (n == 0) {
        krb5_clear_error_message (context);
        return KRB5_SENDAUTH_BADAPPLVERS;
    }
    len = ntohl(len);
    her_appl_version = malloc (len);
    if (her_appl_version == NULL) {
        repl = 2;
        krb5_net_write (context, p_fd, &repl, 1);
        krb5_set_error_message(context, ENOMEM,
                               N_("malloc: out of memory", ""));
        return ENOMEM;
    }
    if ((bytes = krb5_net_read (context, p_fd, her_appl_version, len))) {
        /* PR/267884: String read must always conatain a terminating NUL */
        if (strnlen(her_appl_version, len) == len)
                her_appl_version[len-1] = '\0';

            if (bytes != len ||
                !(*match_appl_version)(match_data, her_appl_version)) {
                repl = 2;
                krb5_net_write (context, p_fd, &repl, 1);
                krb5_set_error_message(context, KRB5_SENDAUTH_BADAPPLVERS,
                                       N_("wrong sendauth version (%s)", ""),
                                       her_appl_version);
                free (her_appl_version);
                return KRB5_SENDAUTH_BADAPPLVERS;
            }
    }
    free (her_appl_version);

    repl = 0;
    if (krb5_net_write (context, p_fd, &repl, 1) != 1) {
        ret = errno;
        krb5_set_error_message(context, ret, "write: %s", strerror(ret));
        return ret;
    }

    krb5_data_zero (&data);
    ret = krb5_read_message (context, p_fd, &data);
    if (ret)
        return ret;

    ret = krb5_rd_req (context,
                       auth_context,
                       &data,
                       server,
                       keytab,
                       &ap_options,
                       ticket);
    krb5_data_free (&data);
    if (ret) {
        krb5_data error_data;
        krb5_error_code ret2;

        ret2 = krb5_mk_error (context,
                              ret,
                              NULL,
                              NULL,
                              NULL,
                              server,
                              NULL,
                              NULL,
                              &error_data);
        if (ret2 == 0) {
            krb5_write_message (context, p_fd, &error_data);
            krb5_data_free (&error_data);
        }
        return ret;
    }

    len = 0;
    if (krb5_net_write (context, p_fd, &len, 4) != 4) {
        ret = errno;
        krb5_set_error_message(context, ret, "write: %s", strerror(ret));
        krb5_free_ticket(context, *ticket);
        *ticket = NULL;
        return ret;
    }

    if (ap_options & AP_OPTS_MUTUAL_REQUIRED) {
        ret = krb5_mk_rep (context, *auth_context, &data);
        if (ret) {
            krb5_free_ticket(context, *ticket);
            *ticket = NULL;
            return ret;
        }

        ret = krb5_write_message (context, p_fd, &data);
        if (ret) {
            krb5_free_ticket(context, *ticket);
            *ticket = NULL;
            return ret;
        }
        krb5_data_free (&data);
    }
    return 0;
}