2 * Copyright (c) 2012, 2013, 2014 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 * NOTE: Some code in this module was derived from code in
34 * mod_auth_gssapi.c which is copyrighted by CESNET. See that file
35 * for full copyright details.
37 * NOTE: Portions of the code in this file were derived from example
38 * code distributed under the Apache 2.0 license:
39 * http://www.apache.org/licenses/LICENSE-2.0
41 * This module implements the Apache server side of the GSSWeb
42 * authentiction type which allows Moonshot to be used for
43 * authentication in web applications. The module consists of two
44 * components: the hook function (gssweb_authenticate_user) that does
45 * most of the work, and an output filter (gssweb_authenticate_filter)
46 * that is registered by the hook function to send the output token
47 * back to the client in a json message that wraps the original
50 * This module uses a simple protocol between the client and server
51 * to exchange GSS tokens and nonce information. The protocol is
52 * described in the protocol.txt file included with module source.
55 #include "mod_auth_gssweb.h"
57 module AP_MODULE_DECLARE_DATA auth_gssweb_module;
59 #define command(name, func, var, type, usage) \
60 AP_INIT_ ## type (name, (void*) func, \
61 (void*)APR_OFFSETOF(gss_auth_config, var), \
62 OR_AUTHCFG | RSRC_CONF, usage)
64 static const command_rec gssweb_config_cmds[] = {
65 command("GSSServiceName", ap_set_string_slot, service_name,
66 TAKE1, "Service name used for Apache authentication."),
71 #define DEFAULT_ENCTYPE "application/x-www-form-urlencoded"
72 #define GSS_MAX_TOKEN_SIZE 4096 //TBD -- check this value
74 /* gssweb_read_req() -- reads the request data into a buffer
76 static int gssweb_read_req(request_rec *r, const char **rbuf, apr_off_t *size)
80 if((rc = ap_setup_client_block(r, REQUEST_CHUNKED_ERROR))) {
84 if(ap_should_client_block(r)) {
86 char argsbuffer[HUGE_STRING_LEN];
87 apr_off_t rsize, len_read, rpos = 0;
88 apr_off_t length = r->remaining;
90 *rbuf = (const char *) apr_pcalloc(r->pool, (apr_size_t) (length + 1));
92 while((len_read = ap_get_client_block(r, argsbuffer, sizeof(argsbuffer))) > 0) {
93 if((rpos + len_read) > length) {
94 rsize = length - rpos;
100 memcpy((char *) *rbuf + rpos, argsbuffer, (size_t) rsize);
107 /* gssweb_get_post_data() -- Gets the token and nonce from the request
110 static int gssweb_get_post_data(request_rec *r, int *nonce, gss_buffer_desc *input_token)
114 const char *key, *val, *type;
118 input_token->length = 0;
119 input_token->value = NULL;
121 if(r->method_number != M_POST) {
122 gss_log(APLOG_MARK, APLOG_DEBUG, 0, r, "gssweb_get_post_data: Request data is not a POST, declining.");
126 type = apr_table_get(r->headers_in, "Content-Type");
127 if(strcasecmp(type, DEFAULT_ENCTYPE) != 0) {
128 gss_log(APLOG_MARK, APLOG_DEBUG, 0, r, "gssweb_get_post_data: Unexpected content type, declining.");
132 if((rc = gssweb_read_req(r, &data, &datalen)) != OK) {
133 gss_log(APLOG_MARK, APLOG_DEBUG, 0, r, "gssweb_get_post_data: Data read error, rc = %d", rc);
137 while(*data && (val = ap_getword(r->pool, &data, '&'))) {
138 gss_log(APLOG_MARK, APLOG_DEBUG, 0, r, "gssweb_get_post_data: obtained val from ap_getword() (%s)", val);
139 key = ap_getword(r->pool, &val, '=');
140 ap_unescape_url((char*)key);
141 ap_unescape_url((char*)val);
142 if (0 == strcasecmp(key, "token")) {
143 gss_log(APLOG_MARK, APLOG_DEBUG, 0, r, "gssweb_get_post_data: found token (%s)", val);
144 input_token->value = malloc(strlen(val));
145 input_token->length = apr_base64_decode(input_token->value, val);
146 gss_log(APLOG_MARK, APLOG_DEBUG, 0, r, "gssweb_get_post_data: Token successfully decoded.");
148 else if (0 == strcasecmp(key, "nonce")) {
149 gss_log(APLOG_MARK, APLOG_DEBUG, 0, r, "gssweb_get_post_data: found nonce (%s)", val);
153 gss_log(APLOG_MARK, APLOG_DEBUG, 0, r, "gssweb_get_post_data: unknown key (%s)", key);
156 if ((0 == *nonce) || (0 == input_token->length)) {
157 gss_log(APLOG_MARK, APLOG_DEBUG, 0, r, "gssweb_get_post_data: nonce (%d) or token len (%d) is 0, declining", *nonce, input_token->length);
161 gss_log(APLOG_MARK, APLOG_DEBUG, 0, r, "gssweb_get_post_data: returning nonce (%d) and token (%d bytes)", *nonce, input_token->length);
166 /* gssweb_authenticate_filter() -- Output filter for gssweb authentication.
167 * Wraps original response in JSON -- adding JSON to the beginning of the
168 * response, escapes double quotes in the original response, and adds JSON
169 * to the end of the response. Handles responses that involve more than
170 * one filter call by maintaining state until an EOS bucket is received.
172 static apr_status_t gssweb_authenticate_filter (ap_filter_t *f,
173 apr_bucket_brigade *brig_in)
175 gss_log(APLOG_MARK, APLOG_DEBUG, 0, f->r, "Entering GSSWeb filter");
177 request_rec *r = f->r;
178 conn_rec *c = r->connection;
179 apr_bucket_brigade *brig_out;
180 apr_bucket *bkt_in = NULL;
181 apr_bucket *bkt_out = NULL;
182 apr_bucket *bkt_eos = NULL;
183 const char *data = NULL;
187 apr_status_t ret = 0;
189 /* get the context from the request */
191 /* if this is the first call for this response, send JSON block */
194 if (NULL = (brig_out = apr_brigade_create(r->pool, c->bucket_alloc))) {
195 // indicate processing error
196 apr_brigade_cleanup(brig_in);
200 //create and send opening JSON block
202 if (?? != (ret = ap_pass_brigade(f->next,pbbOut))) {
203 // indicate a processing error
204 apr_brigade_cleanup(brig_in);
205 apr_brigade_cleanup(brig_out);
210 /* loop through the buckets, escaping and sending each one */
211 for (bkt_in = APR_BRIGADE_FIRST(brig_in);
212 bkt_in != APR_BRIGADE_SENTINEL(brig_in);
213 bkt_in = APR_BUCKET_NEXT(bkt_in))
215 brig_out = apr_brigade_create(r->pool, c->bucket_alloc);
217 /* if this is an EOS, send the JSON closing block */
218 if(APR_BUCKET_IS_EOS(bkt_in))
220 // create and send the JSON closing block
222 // flag that the next filter call will be a new response
224 /* set EOS in the outbound brigade */
225 bkt_eos = apr_bucket_eos_create(c->bucket_alloc);
226 APR_BRIGADE_INSERT_TAIL (brig_out, bkt_eos);
228 /* pass the brigade */
229 if (?? != (ret = ap_pass_brigade(f->next, bkt_out))) {
230 // indicate a processing error
231 apr_brigade_cleanup(brig_in);
232 apr_brigade_cleanup(brig_out);
239 apr_bucket_read(bkt_in, &data, &len, APR_BLOCK_READ);
242 buf = apr_bucket_alloc(len, c->bucket_alloc);
243 bkt_out = apr_bucket_heap_create(buf, len, apr_bucket_free,
246 for(n=0 ; n < len ; ++n) {
250 APR_BRIGADE_INSERT_TAIL(brig_out, bkt_out);
251 if (?? == (ret = ap_pass_brigade(f->next, bkt_out))) {
252 apr_brigade_cleanup(brig_in);
253 apr_brigade_cleanup(brig_out);
258 apr_brigade_cleanup(brig_in);
262 /* gssweb_add_filter() -- Hook to add our output filter to the request
263 * (r). Called for all error responses through the
264 * gssweb_insert_error_filter hook.
267 gssweb_add_filter(request_rec *r)
269 gss_conn_ctx conn_ctx = NULL;
271 /* Get the context for this request */
272 conn_ctx = gss_get_conn_ctx(r);
273 if (conn_ctx == NULL) {
274 gss_log(APLOG_MARK, APLOG_ERR, 0, r, "gssweb_add_filter: Failed to find or create internal context.");
278 /* Add the output filter */
279 ap_add_output_filter("gssweb_auth_filter", (void *)conn_ctx, r, r->connection);
283 /* gssweb_authenticate_user() -- Hook to perform actual user
284 * authentication. Will be called once for each round trip in the GSS
285 * authentication loop. Reads the tokend from the request, calls
286 * gss_accept_sec_context(), and stores the output token and context
287 * in the user data areas. Adds output filter to send the GSS
288 * output token back to the client.
291 gssweb_authenticate_user(request_rec *r)
293 gss_auth_config *conf =
294 (gss_auth_config *) ap_get_module_config(r->per_dir_config,
295 &auth_gssweb_module);
296 const char *auth_line = NULL;
297 const char *type = NULL;
298 char *auth_type = NULL;
299 char *negotiate_ret_value = NULL;
300 gss_conn_ctx conn_ctx = NULL;
302 OM_uint32 major_status, minor_status, minor_status2;
303 gss_buffer_desc input_token = GSS_C_EMPTY_BUFFER;
304 gss_buffer_desc output_token = GSS_C_EMPTY_BUFFER;
305 gss_name_t client_name = GSS_C_NO_NAME;
306 gss_cred_id_t delegated_cred = GSS_C_NO_CREDENTIAL;
307 gss_cred_id_t server_creds = GSS_C_NO_CREDENTIAL;
308 OM_uint32 ret_flags = 0;
311 gss_log(APLOG_MARK, APLOG_DEBUG, 0, r, "Entering GSSWeb authentication");
313 /* Check if this is for our auth type */
314 type = ap_auth_type(r);
315 if (type == NULL || strcasecmp(type, "GSSWeb") != 0) {
316 gss_log(APLOG_MARK, APLOG_DEBUG, 0, r,
317 "gssweb_authenticate_user: AuthType '%s' is not GSSWeb, bailing out",
318 (type) ? type : "(NULL)");
323 /* Set up a GSS context for this request, if there isn't one already */
324 conn_ctx = gss_get_conn_ctx(r);
325 if (conn_ctx == NULL) {
326 gss_log(APLOG_MARK, APLOG_ERR, 0, r, "gssweb_authenticate_user: Failed to create internal context");
327 return HTTP_INTERNAL_SERVER_ERROR;
330 /* Read the token and nonce from the POST */
331 if (0 != gssweb_get_post_data(r, &nonce, &input_token)) {
332 ret = HTTP_UNAUTHORIZED;
333 gss_log(APLOG_MARK, APLOG_ERR, 0, r, "gssweb_authenticate_user: Unable to read nonce or input token.");
336 gss_log(APLOG_MARK, APLOG_DEBUG, 0, r, "gssweb_authenticate_user: GSSWeb nonce value = %u.", nonce);
338 /* If the nonce is set and doesn't match, start over */
339 if ((0 != conn_ctx->nonce) && (conn_ctx->nonce != nonce)) {
340 if (GSS_C_NO_CONTEXT != conn_ctx->context) {
341 gss_delete_sec_context(&minor_status, &conn_ctx->context, GSS_C_NO_BUFFER);
343 conn_ctx->context = GSS_C_NO_CONTEXT;
344 conn_ctx->state = GSS_CTX_EMPTY;
345 conn_ctx->user = NULL;
346 if (0 != conn_ctx->output_token.length) {
347 gss_release_buffer(&minor_status, &(conn_ctx->output_token));
351 /* If the output filter reported an internal server error, return it */
352 if (GSS_CTX_ERROR == conn_ctx->state) {
353 ret = HTTP_INTERNAL_SERVER_ERROR;
354 gss_log(APLOG_MARK, APLOG_ERR, 0, r,
355 "gssweb_authenticate_user: Output filter returned internal server error, reporting.");
359 /* Set-up the output filter (TBD -- register this once?) */
360 ap_register_output_filter("gssweb_auth_filter", gssweb_authenticate_filter, NULL, AP_FTYPE_RESOURCE);
361 ap_add_output_filter("gssweb_auth_filter", (void *)conn_ctx, r, r->connection);
363 /* Acquire server credentials (TBD -- do this once?) */
364 ret = get_gss_creds(r, conf, &server_creds);
367 gss_log(APLOG_MARK, APLOG_DEBUG, 0, r, "gssweb_authenticate_user: Server credentials acquired.");
369 /* Call gss_accept_sec_context */
370 major_status = gss_accept_sec_context(&minor_status,
374 GSS_C_NO_CHANNEL_BINDINGS,
381 gss_log(APLOG_MARK, APLOG_DEBUG, 0, r,
382 "gssweb_authenticate_user: Client %s us their credential",
383 (ret_flags & GSS_C_DELEG_FLAG) ? "delegated" : "didn't delegate");
385 if (GSS_ERROR(major_status)) {
386 gss_log(APLOG_MARK, APLOG_ERR, 0, r,
387 "%s", get_gss_error(r, major_status, minor_status,
388 "gssweb_authenticate_user: Failed to establish authentication"));
389 gss_delete_sec_context(&minor_status, &conn_ctx->context, GSS_C_NO_BUFFER);
390 conn_ctx->context = GSS_C_NO_CONTEXT;
391 conn_ctx->state = GSS_CTX_EMPTY;
392 ret = HTTP_UNAUTHORIZED;
394 gss_log(APLOG_MARK, APLOG_DEBUG, 0, r, "gssweb_authenticate_user: Decoding ouput token.");
397 gss_log(APLOG_MARK, APLOG_DEBUG, 0, r, "gssweb_authenticate_user: Got sec context, storing nonce and output token.");
399 /* Store the nonce & ouput token in the stored context */
400 conn_ctx->nonce = nonce;
401 conn_ctx->output_token = output_token;
403 /* If we aren't done yet, go around again */
404 if (major_status & GSS_S_CONTINUE_NEEDED) {
405 conn_ctx->state = GSS_CTX_IN_PROGRESS;
406 ret = HTTP_UNAUTHORIZED;
410 conn_ctx->state = GSS_CTX_ESTABLISHED;
411 r->user = apr_pstrdup(r->pool, conn_ctx->user);
412 r->ap_auth_type = "GSSWeb";
417 gss_release_cred(&minor_status, &delegated_cred);
419 if (output_token.length)
420 gss_release_buffer(&minor_status, &output_token);
422 if (client_name != GSS_C_NO_NAME)
423 gss_release_name(&minor_status, &client_name);
425 if (server_creds != GSS_C_NO_CREDENTIAL)
426 gss_release_cred(&minor_status, &server_creds);
432 gssweb_register_hooks(apr_pool_t *p)
434 ap_hook_check_user_id(gssweb_authenticate_user, NULL, NULL, APR_HOOK_MIDDLE);
435 ap_hook_insert_error_filter(gssweb_add_filter, NULL, NULL, APR_HOOK_MIDDLE);
438 module AP_MODULE_DECLARE_DATA auth_gssweb_module = {
439 STANDARD20_MODULE_STUFF,
440 gss_config_dir_create,
445 gssweb_register_hooks