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/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
/* lib/krb5/krb/sendauth.c */
/*
* Copyright 1991, 2009 by the Massachusetts Institute of Technology.
* All Rights Reserved.
*
* Export of this software from the United States of America may
* require a specific license from the United States Government.
* It is the responsibility of any person or organization contemplating
* export to obtain such a license before exporting.
*
* WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
* distribute this software and its documentation for any purpose and
* without fee is hereby granted, provided that the above copyright
* notice appear in all copies and that both that copyright notice and
* this permission notice appear in supporting documentation, and that
* the name of M.I.T. not be used in advertising or publicity pertaining
* to distribution of the software without specific, written prior
* permission. Furthermore if you modify this software you must label
* your software as modified software and not distribute it in such a
* fashion that it might be confused with the original M.I.T. software.
* M.I.T. makes no representations about the suitability of
* this software for any purpose. It is provided "as is" without express
* or implied warranty.
*/
#include "k5-int.h"
#include "os-proto.h"
#include "com_err.h"
#include "auth_con.h"
#include <errno.h>
#include <stdio.h>
#include <string.h>
static const char sendauth_version[] = "KRB5_SENDAUTH_V1.0";
krb5_error_code KRB5_CALLCONV
krb5_sendauth(krb5_context context, krb5_auth_context *auth_context,
krb5_pointer fd, char *appl_version, krb5_principal client,
krb5_principal server, krb5_flags ap_req_options,
krb5_data *in_data, krb5_creds *in_creds, krb5_ccache ccache,
krb5_error **error, krb5_ap_rep_enc_part **rep_result,
krb5_creds **out_creds)
{
krb5_octet result;
krb5_creds creds;
krb5_creds * credsp = NULL;
krb5_creds * credspout = NULL;
krb5_error_code retval = 0;
krb5_data inbuf, outbuf[2];
int len;
krb5_ccache use_ccache = 0;
if (error)
*error = 0;
/*
* First, send over the length of the sendauth version string;
* then, we send over the sendauth version. Next, we send
* over the length of the application version strings followed
* by the string itself.
*/
outbuf[0].length = strlen(sendauth_version) + 1;
outbuf[0].data = (char *) sendauth_version;
outbuf[1].length = strlen(appl_version) + 1;
outbuf[1].data = appl_version;
if ((retval = k5_write_messages(context, fd, outbuf, 2)))
return(retval);
/*
* Now, read back a byte: 0 means no error, 1 means bad sendauth
* version, 2 means bad application version
*/
if ((len = krb5_net_read(context, *((int *) fd), (char *)&result, 1)) != 1)
return((len < 0) ? errno : ECONNABORTED);
if (result == 1)
return(KRB5_SENDAUTH_BADAUTHVERS);
else if (result == 2)
return(KRB5_SENDAUTH_BADAPPLVERS);
else if (result != 0)
return(KRB5_SENDAUTH_BADRESPONSE);
/*
* We're finished with the initial negotiations; let's get and
* send over the authentication header. (The AP_REQ message)
*/
/*
* If no credentials were provided, try getting it from the
* credentials cache.
*/
memset(&creds, 0, sizeof(creds));
/*
* See if we need to access the credentials cache
*/
if (!in_creds || !in_creds->ticket.length) {
if (ccache)
use_ccache = ccache;
else if ((retval = krb5int_cc_default(context, &use_ccache)))
goto error_return;
}
if (!in_creds) {
if ((retval = krb5_copy_principal(context, server,
&creds.server)))
goto error_return;
if (client)
retval = krb5_copy_principal(context, client,
&creds.client);
else
retval = krb5_cc_get_principal(context, use_ccache,
&creds.client);
if (retval)
goto error_return;
/* creds.times.endtime = 0; -- memset 0 takes care of this
zero means "as long as possible" */
/* creds.keyblock.enctype = 0; -- as well as this.
zero means no session enctype
preference */
in_creds = &creds;
}
if (!in_creds->ticket.length) {
if ((retval = krb5_get_credentials(context, 0,
use_ccache, in_creds, &credsp)))
goto error_return;
credspout = credsp;
} else {
credsp = in_creds;
}
if (ap_req_options & AP_OPTS_USE_SUBKEY) {
/* Provide some more fodder for random number code.
This isn't strong cryptographically; the point here is
not to guarantee randomness, but to make it less likely
that multiple sessions could pick the same subkey. */
char rnd_data[1024];
GETPEERNAME_ARG3_TYPE len2;
krb5_data d;
d.length = sizeof (rnd_data);
d.data = rnd_data;
len2 = sizeof (rnd_data);
if (getpeername (*(int*)fd, (GETPEERNAME_ARG2_TYPE *) rnd_data,
&len2) == 0) {
d.length = len2;
(void) krb5_c_random_add_entropy (context, KRB5_C_RANDSOURCE_EXTERNAL_PROTOCOL, &d);
}
len2 = sizeof (rnd_data);
if (getsockname (*(int*)fd, (GETSOCKNAME_ARG2_TYPE *) rnd_data,
&len2) == 0) {
d.length = len2;
(void) krb5_c_random_add_entropy (context, KRB5_C_RANDSOURCE_EXTERNAL_PROTOCOL, &d);
}
}
outbuf[0].data = NULL; /* Coverity is confused otherwise */
if ((retval = krb5_mk_req_extended(context, auth_context,
ap_req_options, in_data, credsp,
&outbuf[0])))
goto error_return;
/*
* First write the length of the AP_REQ message, then write
* the message itself.
*/
retval = krb5_write_message(context, fd, &outbuf[0]);
free(outbuf[0].data);
if (retval)
goto error_return;
/*
* Now, read back a message. If it was a null message (the
* length was zero) then there was no error. If not, we the
* authentication was rejected, and we need to return the
* error structure.
*/
if ((retval = krb5_read_message(context, fd, &inbuf)))
goto error_return;
if (inbuf.length) {
if (error) {
if ((retval = krb5_rd_error(context, &inbuf, error))) {
free(inbuf.data);
goto error_return;
}
}
retval = KRB5_SENDAUTH_REJECTED;
free(inbuf.data);
goto error_return;
}
/*
* If we asked for mutual authentication, we should now get a
* length field, followed by a AP_REP message
*/
if ((ap_req_options & AP_OPTS_MUTUAL_REQUIRED)) {
krb5_ap_rep_enc_part *repl = 0;
if ((retval = krb5_read_message(context, fd, &inbuf)))
goto error_return;
if ((retval = krb5_rd_rep(context, *auth_context, &inbuf,
&repl))) {
if (repl)
krb5_free_ap_rep_enc_part(context, repl);
free(inbuf.data);
goto error_return;
}
free(inbuf.data);
/*
* If the user wants to look at the AP_REP message,
* copy it for him
*/
if (rep_result)
*rep_result = repl;
else
krb5_free_ap_rep_enc_part(context, repl);
}
retval = 0; /* Normal return */
if (out_creds) {
*out_creds = credsp;
credspout = NULL;
}
error_return:
krb5_free_cred_contents(context, &creds);
if (credspout != NULL)
krb5_free_creds(context, credspout);
if (!ccache && use_ccache)
krb5_cc_close(context, use_ccache);
return(retval);
}
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