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/* -*- mode: c; indent-tabs-mode: nil -*- */
/*
* Copyright 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 <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <gssapi/gssapi_krb5.h>
/*
* Test program for protocol transition (S4U2Self) and constrained delegation
* (S4U2Proxy)
*
* Note: because of name canonicalization, the following tips may help
* when configuring with Active Directory:
*
* - Create a computer account FOO$
* - Set the UPN to host/foo.domain (no suffix); this is necessary to
* be able to send an AS-REQ as this principal, otherwise you would
* need to use the canonical name (FOO$), which will cause principal
* comparison errors in gss_accept_sec_context().
* - Add a SPN of host/foo.domain
* - Configure the computer account to support constrained delegation with
* protocol transition (Trust this computer for delegation to specified
* services only / Use any authentication protocol)
* - Add host/foo.domain to the keytab (possibly easiest to do this
* with ktadd)
*
* For S4U2Proxy to work the TGT must be forwardable too.
*
* Usage eg:
*
* kinit -k -t test.keytab -f 'host/test.win.mit.edu@WIN.MIT.EDU'
* ./t_s4u delegtest@WIN.MIT.EDU HOST/WIN-EQ7E4AA2WR8.win.mit.edu@WIN.MIT.EDU test.keytab
*/
static gss_OID_desc spnego_mech = { 6, "\053\006\001\005\005\002" };
int use_spnego = 0;
static void displayStatus_1(m, code, type)
char *m;
OM_uint32 code;
int type;
{
OM_uint32 maj_stat, min_stat;
gss_buffer_desc msg;
OM_uint32 msg_ctx;
msg_ctx = 0;
while (1) {
maj_stat = gss_display_status(&min_stat, code,
type, GSS_C_NULL_OID,
&msg_ctx, &msg);
fprintf(stderr, "%s: %s\n", m, (char *)msg.value);
(void) gss_release_buffer(&min_stat, &msg);
if (!msg_ctx)
break;
}
}
static void displayStatus(msg, maj_stat, min_stat)
char *msg;
OM_uint32 maj_stat;
OM_uint32 min_stat;
{
displayStatus_1(msg, maj_stat, GSS_C_GSS_CODE);
displayStatus_1(msg, min_stat, GSS_C_MECH_CODE);
}
static OM_uint32
displayCanonName(OM_uint32 *minor, gss_name_t name, char *tag)
{
gss_name_t canon;
OM_uint32 major, tmp_minor;
gss_buffer_desc buf;
major = gss_canonicalize_name(minor, name,
(gss_OID)gss_mech_krb5, &canon);
if (GSS_ERROR(major)) {
displayStatus("gss_canonicalize_name", major, *minor);
return major;
}
major = gss_display_name(minor, canon, &buf, NULL);
if (GSS_ERROR(major)) {
displayStatus("gss_display_name", major, *minor);
gss_release_name(&tmp_minor, &canon);
return major;
}
printf("%s:\t%s\n", tag, (char *)buf.value);
gss_release_buffer(&tmp_minor, &buf);
gss_release_name(&tmp_minor, &canon);
return GSS_S_COMPLETE;
}
static OM_uint32
displayOID(OM_uint32 *minor, gss_OID oid, char *tag)
{
OM_uint32 major, tmp_minor;
gss_buffer_desc buf;
major = gss_oid_to_str(minor, oid, &buf);
if (GSS_ERROR(major)) {
displayStatus("gss_oid_to_str", major, *minor);
return major;
}
printf("%s:\t%s\n", tag, (char *)buf.value);
gss_release_buffer(&tmp_minor, &buf);
return GSS_S_COMPLETE;
}
static OM_uint32
initAcceptSecContext(OM_uint32 *minor,
gss_cred_id_t claimant_cred_handle,
gss_cred_id_t verifier_cred_handle,
gss_cred_id_t *deleg_cred_handle)
{
OM_uint32 major, tmp_minor;
gss_buffer_desc token, tmp;
gss_ctx_id_t initiator_context = GSS_C_NO_CONTEXT;
gss_ctx_id_t acceptor_context = GSS_C_NO_CONTEXT;
gss_name_t source_name = GSS_C_NO_NAME;
gss_name_t target_name = GSS_C_NO_NAME;
OM_uint32 time_rec;
gss_OID mech = GSS_C_NO_OID;
token.value = NULL;
token.length = 0;
tmp.value = NULL;
tmp.length = 0;
*deleg_cred_handle = GSS_C_NO_CREDENTIAL;
major = gss_inquire_cred(minor, verifier_cred_handle,
&target_name, NULL, NULL, NULL);
if (GSS_ERROR(major)) {
displayStatus("gss_inquire_cred", major, *minor);
return major;
}
displayCanonName(minor, target_name, "Target name");
mech = use_spnego ? (gss_OID)&spnego_mech : (gss_OID)gss_mech_krb5;
displayOID(minor, mech, "Target mech");
major = gss_init_sec_context(minor,
claimant_cred_handle,
&initiator_context,
target_name,
mech,
GSS_C_REPLAY_FLAG | GSS_C_SEQUENCE_FLAG,
GSS_C_INDEFINITE,
GSS_C_NO_CHANNEL_BINDINGS,
GSS_C_NO_BUFFER,
NULL,
&token,
NULL,
&time_rec);
if (target_name != GSS_C_NO_NAME)
(void) gss_release_name(&tmp_minor, &target_name);
if (GSS_ERROR(major)) {
displayStatus("gss_init_sec_context", major, *minor);
return major;
}
(void) gss_delete_sec_context(minor, &initiator_context, NULL);
mech = GSS_C_NO_OID;
major = gss_accept_sec_context(minor,
&acceptor_context,
verifier_cred_handle,
&token,
GSS_C_NO_CHANNEL_BINDINGS,
&source_name,
&mech,
&tmp,
NULL,
&time_rec,
deleg_cred_handle);
if (GSS_ERROR(major))
displayStatus("gss_accept_sec_context", major, *minor);
else {
displayCanonName(minor, source_name, "Source name");
displayOID(minor, mech, "Source mech");
}
(void) gss_release_name(&tmp_minor, &source_name);
(void) gss_delete_sec_context(&tmp_minor, &acceptor_context, NULL);
(void) gss_release_buffer(&tmp_minor, &token);
(void) gss_release_buffer(&tmp_minor, &tmp);
(void) gss_release_oid(&tmp_minor, &mech);
return major;
}
static OM_uint32
constrainedDelegate(OM_uint32 *minor,
gss_OID_set desired_mechs,
gss_name_t target,
gss_cred_id_t delegated_cred_handle,
gss_cred_id_t verifier_cred_handle)
{
OM_uint32 major, tmp_minor;
gss_ctx_id_t initiator_context = GSS_C_NO_CONTEXT;
gss_name_t cred_name = GSS_C_NO_NAME;
OM_uint32 time_rec, lifetime;
gss_cred_usage_t usage;
gss_buffer_desc token;
gss_OID_set mechs;
printf("Constrained delegation tests follow\n");
printf("-----------------------------------\n\n");
if (gss_inquire_cred(minor, verifier_cred_handle, &cred_name,
&lifetime, &usage, NULL) == GSS_S_COMPLETE) {
displayCanonName(minor, cred_name, "Proxy name");
gss_release_name(&tmp_minor, &cred_name);
}
displayCanonName(minor, target, "Target name");
if (gss_inquire_cred(minor, delegated_cred_handle, &cred_name,
&lifetime, &usage, &mechs) == GSS_S_COMPLETE) {
displayCanonName(minor, cred_name, "Delegated name");
displayOID(minor, &mechs->elements[0], "Delegated mech");
gss_release_name(&tmp_minor, &cred_name);
}
printf("\n");
major = gss_init_sec_context(minor,
delegated_cred_handle,
&initiator_context,
target,
mechs ? &mechs->elements[0] :
(gss_OID)gss_mech_krb5,
GSS_C_REPLAY_FLAG | GSS_C_SEQUENCE_FLAG,
GSS_C_INDEFINITE,
GSS_C_NO_CHANNEL_BINDINGS,
GSS_C_NO_BUFFER,
NULL,
&token,
NULL,
&time_rec);
if (GSS_ERROR(major))
displayStatus("gss_init_sec_context", major, *minor);
(void) gss_release_buffer(&tmp_minor, &token);
(void) gss_delete_sec_context(&tmp_minor, &initiator_context, NULL);
(void) gss_release_oid_set(&tmp_minor, &mechs);
return major;
}
int main(int argc, char *argv[])
{
OM_uint32 minor, major;
gss_cred_id_t impersonator_cred_handle = GSS_C_NO_CREDENTIAL;
gss_cred_id_t user_cred_handle = GSS_C_NO_CREDENTIAL;
gss_cred_id_t delegated_cred_handle = GSS_C_NO_CREDENTIAL;
gss_name_t user = GSS_C_NO_NAME, target = GSS_C_NO_NAME;
gss_OID_set_desc mechs;
gss_OID_set actual_mechs = GSS_C_NO_OID_SET;
gss_buffer_desc buf;
if (argc < 2 || argc > 5) {
fprintf(stderr, "Usage: %s [--spnego] [user] "
"[proxy-target] [keytab]\n", argv[0]);
fprintf(stderr, " proxy-target and keytab are optional\n");
exit(1);
}
if (strcmp(argv[1], "--spnego") == 0) {
use_spnego++;
argc--;
argv++;
}
buf.value = argv[1];
buf.length = strlen((char *)buf.value);
major = gss_import_name(&minor, &buf,
(gss_OID)GSS_KRB5_NT_PRINCIPAL_NAME,
&user);
if (GSS_ERROR(major)) {
displayStatus("gss_import_name(user)", major, minor);
goto out;
}
if (argc > 2 && strcmp(argv[2], "-")) {
buf.value = argv[2];
buf.length = strlen((char *)buf.value);
major = gss_import_name(&minor, &buf,
(gss_OID)GSS_KRB5_NT_PRINCIPAL_NAME,
&target);
if (GSS_ERROR(major)) {
displayStatus("gss_import_name(target)", major, minor);
goto out;
}
} else {
target = GSS_C_NO_NAME;
}
if (argc > 3) {
major = krb5_gss_register_acceptor_identity(argv[3]);
if (GSS_ERROR(major)) {
displayStatus("krb5_gss_register_acceptor_identity",
major, minor);
goto out;
}
}
mechs.elements = use_spnego ? (gss_OID)&spnego_mech :
(gss_OID)gss_mech_krb5;
mechs.count = 1;
/* get default cred */
major = gss_acquire_cred(&minor,
GSS_C_NO_NAME,
GSS_C_INDEFINITE,
&mechs,
GSS_C_BOTH,
&impersonator_cred_handle,
&actual_mechs,
NULL);
if (GSS_ERROR(major)) {
displayStatus("gss_acquire_cred", major, minor);
goto out;
}
(void) gss_release_oid_set(&minor, &actual_mechs);
printf("Protocol transition tests follow\n");
printf("-----------------------------------\n\n");
/* get S4U2Self cred */
major = gss_acquire_cred_impersonate_name(&minor,
impersonator_cred_handle,
user,
GSS_C_INDEFINITE,
&mechs,
GSS_C_INITIATE,
&user_cred_handle,
&actual_mechs,
NULL);
if (GSS_ERROR(major)) {
displayStatus("gss_acquire_cred_impersonate_name", major, minor);
goto out;
}
major = initAcceptSecContext(&minor,
user_cred_handle,
impersonator_cred_handle,
&delegated_cred_handle);
if (GSS_ERROR(major))
goto out;
printf("\n");
if (target != GSS_C_NO_NAME &&
delegated_cred_handle != GSS_C_NO_CREDENTIAL) {
major = constrainedDelegate(&minor, &mechs, target,
delegated_cred_handle,
impersonator_cred_handle);
} else if (target != GSS_C_NO_NAME) {
fprintf(stderr, "Warning: no delegated credentials handle returned\n\n");
fprintf(stderr, "Verify:\n\n");
fprintf(stderr, " - The TGT for the impersonating service is forwardable\n");
fprintf(stderr, " - The T2A4D flag set on the impersonating service's UAC\n");
fprintf(stderr, " - The user is not marked sensitive and cannot be delegated\n");
fprintf(stderr, "\n");
}
out:
(void) gss_release_name(&minor, &user);
(void) gss_release_name(&minor, &target);
(void) gss_release_cred(&minor, &delegated_cred_handle);
(void) gss_release_cred(&minor, &impersonator_cred_handle);
(void) gss_release_cred(&minor, &user_cred_handle);
(void) gss_release_oid_set(&minor, &actual_mechs);
return GSS_ERROR(major) ? 1 : 0;
}
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