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_ctx_id_t *outGSSContext,
61 client_cb_fn clientCb,
65 OM_uint32 majorStatus;
66 OM_uint32 minorStatus = 0;
67 gss_ctx_id_t gssContext = GSS_C_NO_CONTEXT;
68 gss_name_t clientName = GSS_C_NO_NAME;
69 gss_buffer_desc clientDisplayName = {0, NULL};
71 char *inputTokenBuffer = NULL;
72 size_t inputTokenBufferLength = 0;
73 gss_buffer_desc inputToken; /* buffer received from the server */
76 if (inSocket < 0 ) { err = EINVAL; }
77 if (!outGSSContext) { err = EINVAL; }
80 * The main authentication loop:
82 * GSS is a multimechanism API. The number of packet exchanges required to
83 * authenticatevaries between mechanisms. As a result, we need to loop reading
84 * input tokens from the client, calling gss_accept_sec_context on the input
85 * tokens and send the resulting output tokens back to the client until we
86 * get GSS_S_COMPLETE or an error.
88 * When we are done, save the client principal so we can make authorization
92 majorStatus = GSS_S_CONTINUE_NEEDED;
93 while (!err && (majorStatus != GSS_S_COMPLETE)) {
94 /* Clean up old input buffer */
95 if (inputTokenBuffer != NULL) {
96 free (inputTokenBuffer);
97 inputTokenBuffer = NULL; /* don't double-free */
100 err = gsscon_read_token (inSocket, &inputTokenBuffer, &inputTokenBufferLength);
103 /* Set up input buffers for the next run through the loop */
104 inputToken.value = inputTokenBuffer;
105 inputToken.length = inputTokenBufferLength;
109 /* buffer to send to the server */
110 gss_buffer_desc outputToken = { 0, NULL };
113 * accept_sec_context does the actual work of taking the client's
114 * request and generating an appropriate reply. Note that we pass
115 * GSS_C_NO_CREDENTIAL for the service principal.
117 // printf ("Calling gss_accept_sec_context...\n");
118 majorStatus = gss_accept_sec_context (&minorStatus,
122 GSS_C_NO_CHANNEL_BINDINGS,
124 NULL /* actual_mech_type */,
126 NULL /* req_flags */,
128 NULL /* delegated_cred_handle */);
130 if ((outputToken.length > 0) && (outputToken.value != NULL)) {
131 /* Send the output token to the client (even on error) */
132 err = gsscon_write_token (inSocket, outputToken.value, outputToken.length);
134 /* free the output token */
135 gss_release_buffer (&minorStatus, &outputToken);
139 if ((majorStatus != GSS_S_COMPLETE) && (majorStatus != GSS_S_CONTINUE_NEEDED)) {
140 gsscon_print_gss_errors ("gss_accept_sec_context", majorStatus, minorStatus);
141 err = minorStatus ? minorStatus : majorStatus;
146 majorStatus = gss_display_name(&minorStatus, clientName, &clientDisplayName, NULL);
147 if (GSS_ERROR(majorStatus)) {
148 gsscon_print_gss_errors("gss_display_name", majorStatus, minorStatus);
152 err = clientCb(clientName, &clientDisplayName, clientCbData);
156 *outGSSContext = gssContext;
159 gsscon_print_error (err, "Authenticate failed");
162 if (inputTokenBuffer) { free (inputTokenBuffer); }
163 if (gssContext != GSS_C_NO_CONTEXT) {
164 gss_delete_sec_context (&minorStatus, &gssContext, GSS_C_NO_BUFFER); }
165 if (clientName != GSS_C_NO_NAME)
166 gss_release_name(&minorStatus, &clientName);
167 if (clientDisplayName.value != NULL)
168 gss_release_buffer(&minorStatus, &clientDisplayName);
173 /* --------------------------------------------------------------------------- */
175 static int ServicePrincipalIsValidForService (const char *inServicePrincipal)
178 krb5_context context = NULL;
179 krb5_principal principal = NULL;
181 if (!inServicePrincipal) { err = EINVAL; }
184 err = krb5_init_context (&context);
188 err = krb5_parse_name (context, inServicePrincipal, &principal);
193 * Here is where we check to see if the service principal the client
194 * used is valid. Typically we would just check that the first component
195 * is the name of the service provided by the server. This check exists
196 * to make sure the server is using the correct key in its keytab since
197 * we passed GSS_C_NO_CREDENTIAL into gss_accept_sec_context().
199 if (gServiceName && strcmp (gServiceName,
200 krb5_princ_name (context, principal)->data) != 0) {
201 err = KRB5KRB_AP_WRONG_PRINC;
205 if (principal) { krb5_free_principal (context, principal); }
206 if (context ) { krb5_free_context (context); }
212 /* --------------------------------------------------------------------------- */
214 static int ClientPrincipalIsAuthorizedForService (const char *inClientPrincipal)
218 * Here is where the server checks to see if the client principal should
219 * be allowed to use your service. Typically it should check both the name
220 * and the realm, since with cross-realm shared keys, a user at another
221 * realm may be trying to contact your service.
230 /* --------------------------------------------------------------------------- */
232 int gsscon_authorize (gss_ctx_id_t inContext,
234 int *outAuthorizationError)
237 OM_uint32 majorStatus;
238 OM_uint32 minorStatus = 0;
239 gss_name_t clientName = NULL;
240 gss_name_t serviceName = NULL;
241 char *clientPrincipal = NULL;
242 char *servicePrincipal = NULL;
244 if (!inContext ) { err = EINVAL; }
245 if (!outAuthorized ) { err = EINVAL; }
246 if (!outAuthorizationError) { err = EINVAL; }
249 /* Get the client and service principals used to authenticate */
250 majorStatus = gss_inquire_context (&minorStatus,
254 NULL, NULL, NULL, NULL, NULL);
255 if (majorStatus != GSS_S_COMPLETE) {
256 err = minorStatus ? minorStatus : majorStatus;
261 /* Pull the client principal string out of the gss name */
262 gss_buffer_desc nameToken;
264 majorStatus = gss_display_name (&minorStatus,
268 if (majorStatus != GSS_S_COMPLETE) {
269 err = minorStatus ? minorStatus : majorStatus;
273 clientPrincipal = malloc (nameToken.length + 1);
274 if (clientPrincipal == NULL) { err = ENOMEM; }
278 memcpy (clientPrincipal, nameToken.value, nameToken.length);
279 clientPrincipal[nameToken.length] = '\0';
282 if (nameToken.value) { gss_release_buffer (&minorStatus, &nameToken); }
286 // /* Pull the service principal string out of the gss name */
287 // gss_buffer_desc nameToken;
289 // majorStatus = gss_display_name (&minorStatus,
293 // if (majorStatus != GSS_S_COMPLETE) {
294 // err = minorStatus ? minorStatus : majorStatus;
298 // servic7ePrincipal = malloc (nameToken.length + 1);
299 // if (servicePrincipal == NULL) { err = ENOMEM; }
303 // memcpy (servicePrincipal, nameToken.value, nameToken.length);
304 // servicePrincipal[nameToken.length] = '\0';
307 // if (nameToken.value) { gss_release_buffer (&minorStatus, &nameToken); }
311 // int authorizationErr = ServicePrincipalIsValidForService (servicePr// incipal);
313 // if (!authorizationErr) {
315 int authorizationErr = 0;
316 authorizationErr = ClientPrincipalIsAuthorizedForService (clientPrincipal);
320 // printf ("'%s' is%s authorized for service '%s'\n",
321 // clientPrincipal, authorizationErr ? " NOT" : "", servicePrincipal);
323 *outAuthorized = !authorizationErr;
324 *outAuthorizationError = authorizationErr;
327 if (serviceName ) { gss_release_name (&minorStatus, &serviceName); }
328 if (clientName ) { gss_release_name (&minorStatus, &clientName); }
329 if (clientPrincipal ) { free (clientPrincipal); }
330 if (servicePrincipal) { free (servicePrincipal); }