270 lines
7.8 KiB
C
270 lines
7.8 KiB
C
/*
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* Copyright (c) 1997-2007 Kungliga Tekniska Högskolan
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* (Royal Institute of Technology, Stockholm, Sweden).
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* 3. Neither the name of the Institute nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include "krb5_locl.h"
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/*
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* See `sendauth.c' for the format.
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*/
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static krb5_boolean
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match_exact(const void *data, const char *appl_version)
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{
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return strcmp(data, appl_version) == 0;
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}
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/**
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* Perform the server side of the sendauth protocol.
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*
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* @param context Kerberos 5 context.
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* @param auth_context authentication context of the peer.
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* @param p_fd socket associated to the connection.
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* @param appl_version server-specific string.
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* @param server server principal.
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* @param flags if KRB5_RECVAUTH_IGNORE_VERSION is set, skip the sendauth version
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* part of the protocol.
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* @param keytab server keytab.
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* @param ticket on success, set to the authenticated client credentials.
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* Must be deallocated with krb5_free_ticket(). If not
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* interested, pass a NULL value.
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*
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* @return 0 to indicate success. Otherwise a Kerberos error code is
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* returned, see krb5_get_error_message().
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*/
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KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
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krb5_recvauth(krb5_context context,
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krb5_auth_context *auth_context,
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krb5_pointer p_fd,
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const char *appl_version,
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krb5_principal server,
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int32_t flags,
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krb5_keytab keytab,
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krb5_ticket **ticket)
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{
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return krb5_recvauth_match_version(context, auth_context, p_fd,
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match_exact, appl_version,
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server, flags,
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keytab, ticket);
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}
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/**
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* Perform the server side of the sendauth protocol like krb5_recvauth(), but support
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* a user-specified callback, \a match_appl_version, to perform the match of the application
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* version \a match_data.
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*/
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KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
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krb5_recvauth_match_version(krb5_context context,
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krb5_auth_context *auth_context,
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krb5_pointer p_fd,
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krb5_boolean (*match_appl_version)(const void *,
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const char*),
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const void *match_data,
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krb5_principal server,
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int32_t flags,
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krb5_keytab keytab,
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krb5_ticket **ticket)
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{
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krb5_error_code ret;
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const char *version = KRB5_SENDAUTH_VERSION;
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char her_version[sizeof(KRB5_SENDAUTH_VERSION)];
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char *her_appl_version;
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uint32_t len;
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u_char repl;
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krb5_data data;
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krb5_flags ap_options;
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ssize_t n;
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/*
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* If there are no addresses in auth_context, get them from `fd'.
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*/
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if (*auth_context == NULL) {
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ret = krb5_auth_con_init (context, auth_context);
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if (ret)
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return ret;
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}
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ret = krb5_auth_con_setaddrs_from_fd (context,
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*auth_context,
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p_fd);
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if (ret)
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return ret;
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/*
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* Expect SENDAUTH protocol version.
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*/
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if(!(flags & KRB5_RECVAUTH_IGNORE_VERSION)) {
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n = krb5_net_read (context, p_fd, &len, 4);
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if (n < 0) {
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ret = errno ? errno : EINVAL;
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krb5_set_error_message(context, ret, "read: %s", strerror(ret));
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return ret;
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}
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if (n == 0) {
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krb5_set_error_message(context, KRB5_SENDAUTH_BADAUTHVERS,
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N_("Failed to receive sendauth data", ""));
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return KRB5_SENDAUTH_BADAUTHVERS;
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}
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len = ntohl(len);
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if (len != sizeof(her_version)
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|| krb5_net_read (context, p_fd, her_version, len) != len
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|| strncmp (version, her_version, len) != 0) {
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repl = 1;
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krb5_net_write (context, p_fd, &repl, 1);
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krb5_clear_error_message (context);
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return KRB5_SENDAUTH_BADAUTHVERS;
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}
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}
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/*
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* Expect application protocol version.
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*/
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n = krb5_net_read (context, p_fd, &len, 4);
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if (n < 0) {
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ret = errno ? errno : EINVAL;
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krb5_set_error_message(context, ret, "read: %s", strerror(ret));
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return ret;
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}
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if (n == 0) {
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krb5_clear_error_message (context);
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return KRB5_SENDAUTH_BADAPPLVERS;
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}
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len = ntohl(len);
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if (len > 1024 * 1024) {
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krb5_set_error_message(context, ret = KRB5_SENDAUTH_REJECTED,
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"AP-REQ too long");
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return ret;
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}
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her_appl_version = malloc (len);
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if (her_appl_version == NULL) {
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repl = 2;
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krb5_net_write (context, p_fd, &repl, 1);
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return krb5_enomem(context);
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}
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if (krb5_net_read (context, p_fd, her_appl_version, len) != len
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|| !(*match_appl_version)(match_data, her_appl_version)) {
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repl = 2;
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krb5_net_write (context, p_fd, &repl, 1);
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krb5_set_error_message(context, KRB5_SENDAUTH_BADAPPLVERS,
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N_("wrong sendauth application version (%s)", ""),
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her_appl_version);
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free (her_appl_version);
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return KRB5_SENDAUTH_BADAPPLVERS;
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}
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free (her_appl_version);
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/*
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* Send OK.
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*/
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repl = 0;
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if (krb5_net_write (context, p_fd, &repl, 1) != 1) {
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ret = errno ? errno : EINVAL;
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krb5_set_error_message(context, ret, "write: %s", strerror(ret));
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return ret;
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}
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/*
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* Until here, the fields in the message were in cleartext and unauthenticated.
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* From now on, Kerberos kicks in.
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*/
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/*
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* Expect AP_REQ.
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*/
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krb5_data_zero (&data);
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ret = krb5_read_message (context, p_fd, &data);
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if (ret)
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return ret;
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ret = krb5_rd_req (context,
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auth_context,
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&data,
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server,
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keytab,
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&ap_options,
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ticket);
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krb5_data_free (&data);
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if (ret) {
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krb5_data error_data;
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krb5_error_code ret2;
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ret2 = krb5_mk_error (context,
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ret,
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NULL,
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NULL,
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NULL,
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server,
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NULL,
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NULL,
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&error_data);
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if (ret2 == 0) {
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krb5_write_message (context, p_fd, &error_data);
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krb5_data_free (&error_data);
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}
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return ret;
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}
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/*
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* Send OK.
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*/
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len = 0;
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if (krb5_net_write (context, p_fd, &len, 4) != 4) {
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ret = errno ? errno : EINVAL;
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krb5_set_error_message(context, ret, "write: %s", strerror(ret));
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krb5_free_ticket(context, *ticket);
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*ticket = NULL;
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return ret;
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}
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/*
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* If client requires mutual authentication, send AP_REP.
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*/
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if (ap_options & AP_OPTS_MUTUAL_REQUIRED) {
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ret = krb5_mk_rep (context, *auth_context, &data);
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if (ret) {
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krb5_free_ticket(context, *ticket);
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*ticket = NULL;
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return ret;
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}
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ret = krb5_write_message (context, p_fd, &data);
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if (ret) {
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krb5_free_ticket(context, *ticket);
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*ticket = NULL;
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return ret;
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}
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krb5_data_free (&data);
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}
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return 0;
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}
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