2 * Copyright (c) 2012, JANET(UK)
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of JANET(UK) nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
20 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
24 * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
25 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
26 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
27 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
29 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
30 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
31 * OF THE POSSIBILITY OF SUCH DAMAGE.
33 * This code was adapted from the MIT Kerberos Consortium's
34 * GSS example code, which was distributed under the following
37 * Copyright 2004-2006 Massachusetts Institute of Technology.
38 * All Rights Reserved.
40 * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
41 * distribute this software and its documentation for any purpose and
42 * without fee is hereby granted, provided that the above copyright
43 * notice appear in all copies and that both that copyright notice and
44 * this permission notice appear in supporting documentation, and that
45 * the name of M.I.T. not be used in advertising or publicity pertaining
46 * to distribution of the software without specific, written prior
47 * permission. Furthermore if you modify this software you must label
48 * your software as modified software and not distribute it in such a
49 * fashion that it might be confused with the original M.I.T. software.
50 * M.I.T. makes no representations about the suitability of
51 * this software for any purpose. It is provided "as is" without express
52 * or implied warranty.
57 const char *gServiceName = NULL;
59 int gsscon_passive_authenticate (int inSocket,
60 gss_buffer_desc inNameBuffer,
61 gss_ctx_id_t *outGSSContext,
62 client_cb_fn clientCb,
66 OM_uint32 majorStatus;
67 OM_uint32 minorStatus = 0;
68 gss_ctx_id_t gssContext = GSS_C_NO_CONTEXT;
69 gss_name_t clientName = GSS_C_NO_NAME, serviceName = GSS_C_NO_NAME;
70 gss_cred_id_t acceptorCredentials = NULL;
71 gss_buffer_desc clientDisplayName = {0, NULL};
72 char *inputTokenBuffer = NULL;
73 size_t inputTokenBufferLength = 0;
74 gss_buffer_desc inputToken; /* buffer received from the server */
76 if (inSocket < 0 ) { err = EINVAL; }
77 if (!outGSSContext) { err = EINVAL; }
80 majorStatus = gss_import_name (&minorStatus, &inNameBuffer, (gss_OID) GSS_KRB5_NT_PRINCIPAL_NAME, &serviceName);
81 if (majorStatus != GSS_S_COMPLETE) {
82 gsscon_print_gss_errors ("gss_import_name(serviceName)", majorStatus, minorStatus);
83 err = minorStatus ? minorStatus : majorStatus;
87 majorStatus = gss_acquire_cred ( &minorStatus, serviceName,
88 GSS_C_INDEFINITE, GSS_C_NO_OID_SET,
89 GSS_C_ACCEPT, &acceptorCredentials,
90 NULL /*mechs out*/, NULL /*time out*/);
91 if (majorStatus != GSS_S_COMPLETE) {
92 gsscon_print_gss_errors ("gss_acquire_cred", majorStatus, minorStatus);
93 err = minorStatus ? minorStatus : majorStatus;
98 * The main authentication loop:
100 * GSS is a multimechanism API. The number of packet exchanges required to
101 * authenticatevaries between mechanisms. As a result, we need to loop reading
102 * input tokens from the client, calling gss_accept_sec_context on the input
103 * tokens and send the resulting output tokens back to the client until we
104 * get GSS_S_COMPLETE or an error.
106 * When we are done, save the client principal so we can make authorization
110 majorStatus = GSS_S_CONTINUE_NEEDED;
111 while (!err && (majorStatus != GSS_S_COMPLETE)) {
112 /* Clean up old input buffer */
113 if (inputTokenBuffer != NULL) {
114 free (inputTokenBuffer);
115 inputTokenBuffer = NULL; /* don't double-free */
118 err = gsscon_read_token (inSocket, &inputTokenBuffer, &inputTokenBufferLength);
121 /* Set up input buffers for the next run through the loop */
122 inputToken.value = inputTokenBuffer;
123 inputToken.length = inputTokenBufferLength;
127 /* buffer to send to the server */
128 gss_buffer_desc outputToken = { 0, NULL };
131 * accept_sec_context does the actual work of taking the client's
132 * request and generating an appropriate reply. */
133 majorStatus = gss_accept_sec_context (&minorStatus,
137 GSS_C_NO_CHANNEL_BINDINGS,
139 NULL /* actual_mech_type */,
141 NULL /* req_flags */,
143 NULL /* delegated_cred_handle */);
145 if ((outputToken.length > 0) && (outputToken.value != NULL)) {
146 /* Send the output token to the client (even on error) */
147 err = gsscon_write_token (inSocket, outputToken.value, outputToken.length);
149 /* free the output token */
150 gss_release_buffer (&minorStatus, &outputToken);
154 if ((majorStatus != GSS_S_COMPLETE) && (majorStatus != GSS_S_CONTINUE_NEEDED)) {
155 gsscon_print_gss_errors ("gss_accept_sec_context", majorStatus, minorStatus);
156 err = minorStatus ? minorStatus : majorStatus;
161 majorStatus = gss_display_name(&minorStatus, clientName, &clientDisplayName, NULL);
162 if (GSS_ERROR(majorStatus)) {
163 gsscon_print_gss_errors("gss_display_name", majorStatus, minorStatus);
167 err = clientCb(clientName, &clientDisplayName, clientCbData);
171 *outGSSContext = gssContext;
174 gsscon_print_error (err, "Authenticate failed");
177 if (inputTokenBuffer) { free (inputTokenBuffer); }
178 if (gssContext != GSS_C_NO_CONTEXT) {
179 gss_delete_sec_context (&minorStatus, &gssContext, GSS_C_NO_BUFFER); }
180 if (clientName != GSS_C_NO_NAME)
181 gss_release_name(&minorStatus, &clientName);
182 if (clientDisplayName.value != NULL)
183 gss_release_buffer(&minorStatus, &clientDisplayName);
184 gss_release_name( &minorStatus, &serviceName);
185 gss_release_cred( &minorStatus, &acceptorCredentials);
190 /* --------------------------------------------------------------------------- */
192 static int ServicePrincipalIsValidForService (const char *inServicePrincipal)
195 krb5_context context = NULL;
196 krb5_principal principal = NULL;
198 if (!inServicePrincipal) { err = EINVAL; }
201 err = krb5_init_context (&context);
205 err = krb5_parse_name (context, inServicePrincipal, &principal);
210 * Here is where we check to see if the service principal the client
211 * used is valid. Typically we would just check that the first component
212 * is the name of the service provided by the server. This check exists
213 * to make sure the server is using the correct key in its keytab since
214 * we passed GSS_C_NO_CREDENTIAL into gss_accept_sec_context().
216 if (gServiceName && strcmp (gServiceName,
217 krb5_princ_name (context, principal)->data) != 0) {
218 err = KRB5KRB_AP_WRONG_PRINC;
222 if (principal) { krb5_free_principal (context, principal); }
223 if (context ) { krb5_free_context (context); }
229 /* --------------------------------------------------------------------------- */
231 static int ClientPrincipalIsAuthorizedForService (const char *inClientPrincipal)
235 * Here is where the server checks to see if the client principal should
236 * be allowed to use your service. Typically it should check both the name
237 * and the realm, since with cross-realm shared keys, a user at another
238 * realm may be trying to contact your service.
247 /* --------------------------------------------------------------------------- */
249 int gsscon_authorize (gss_ctx_id_t inContext,
251 int *outAuthorizationError)
254 OM_uint32 majorStatus;
255 OM_uint32 minorStatus = 0;
256 gss_name_t clientName = NULL;
257 gss_name_t serviceName = NULL;
258 char *clientPrincipal = NULL;
259 char *servicePrincipal = NULL;
261 if (!inContext ) { err = EINVAL; }
262 if (!outAuthorized ) { err = EINVAL; }
263 if (!outAuthorizationError) { err = EINVAL; }
266 /* Get the client and service principals used to authenticate */
267 majorStatus = gss_inquire_context (&minorStatus,
271 NULL, NULL, NULL, NULL, NULL);
272 if (majorStatus != GSS_S_COMPLETE) {
273 err = minorStatus ? minorStatus : majorStatus;
278 /* Pull the client principal string out of the gss name */
279 gss_buffer_desc nameToken;
281 majorStatus = gss_display_name (&minorStatus,
285 if (majorStatus != GSS_S_COMPLETE) {
286 err = minorStatus ? minorStatus : majorStatus;
290 clientPrincipal = malloc (nameToken.length + 1);
291 if (clientPrincipal == NULL) { err = ENOMEM; }
295 memcpy (clientPrincipal, nameToken.value, nameToken.length);
296 clientPrincipal[nameToken.length] = '\0';
299 if (nameToken.value) { gss_release_buffer (&minorStatus, &nameToken); }
303 // /* Pull the service principal string out of the gss name */
304 // gss_buffer_desc nameToken;
306 // majorStatus = gss_display_name (&minorStatus,
310 // if (majorStatus != GSS_S_COMPLETE) {
311 // err = minorStatus ? minorStatus : majorStatus;
315 // servic7ePrincipal = malloc (nameToken.length + 1);
316 // if (servicePrincipal == NULL) { err = ENOMEM; }
320 // memcpy (servicePrincipal, nameToken.value, nameToken.length);
321 // servicePrincipal[nameToken.length] = '\0';
324 // if (nameToken.value) { gss_release_buffer (&minorStatus, &nameToken); }
328 // int authorizationErr = ServicePrincipalIsValidForService (servicePr// incipal);
330 // if (!authorizationErr) {
332 int authorizationErr = 0;
333 authorizationErr = ClientPrincipalIsAuthorizedForService (clientPrincipal);
337 // printf ("'%s' is%s authorized for service '%s'\n",
338 // clientPrincipal, authorizationErr ? " NOT" : "", servicePrincipal);
340 *outAuthorized = !authorizationErr;
341 *outAuthorizationError = authorizationErr;
344 if (serviceName ) { gss_release_name (&minorStatus, &serviceName); }
345 if (clientName ) { gss_release_name (&minorStatus, &clientName); }
346 if (clientPrincipal ) { free (clientPrincipal); }
347 if (servicePrincipal) { free (servicePrincipal); }