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/*
* 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;
}
/**
* Perform the server side of the sendauth protocol.
*
* @param context Kerberos 5 context.
* @param auth_context authentication context of the peer.
* @param p_fd socket associated to the connection.
* @param appl_version server-specific string.
* @param server server principal.
* @param flags if KRB5_RECVAUTH_IGNORE_VERSION is set, skip the sendauth version
* part of the protocol.
* @param keytab server keytab.
* @param ticket on success, set to the authenticated client credentials.
* Must be deallocated with krb5_free_ticket(). If not
* interested, pass a NULL value.
*
* @return 0 to indicate success. Otherwise a Kerberos error code is
* returned, see krb5_get_error_message().
*/
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);
}
/**
* Perform the server side of the sendauth protocol like krb5_recvauth(), but support
* a user-specified callback, \a match_appl_version, to perform the match of the application
* version \a match_data.
*/
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;
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;
/*
* Expect SENDAUTH protocol version.
*/
if(!(flags & KRB5_RECVAUTH_IGNORE_VERSION)) {
n = krb5_net_read (context, p_fd, &len, 4);
if (n < 0) {
ret = errno ? errno : EINVAL;
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) != 0) {
repl = 1;
krb5_net_write (context, p_fd, &repl, 1);
krb5_clear_error_message (context);
return KRB5_SENDAUTH_BADAUTHVERS;
}
}
/*
* Expect application protocol version.
*/
n = krb5_net_read (context, p_fd, &len, 4);
if (n < 0) {
ret = errno ? errno : EINVAL;
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);
return krb5_enomem(context);
}
if (krb5_net_read (context, p_fd, her_appl_version, len) != 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 application version (%s)", ""),
her_appl_version);
free (her_appl_version);
return KRB5_SENDAUTH_BADAPPLVERS;
}
free (her_appl_version);
/*
* Send OK.
*/
repl = 0;
if (krb5_net_write (context, p_fd, &repl, 1) != 1) {
ret = errno ? errno : EINVAL;
krb5_set_error_message(context, ret, "write: %s", strerror(ret));
return ret;
}
/*
* Until here, the fields in the message were in cleartext and unauthenticated.
* From now on, Kerberos kicks in.
*/
/*
* Expect AP_REQ.
*/
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;
}
/*
* Send OK.
*/
len = 0;
if (krb5_net_write (context, p_fd, &len, 4) != 4) {
ret = errno ? errno : EINVAL;
krb5_set_error_message(context, ret, "write: %s", strerror(ret));
krb5_free_ticket(context, *ticket);
*ticket = NULL;
return ret;
}
/*
* If client requires mutual authentication, send AP_REP.
*/
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;
}
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