xref: /freebsd/sys/kgssapi/gss_impl.c (revision 64038db825d64fb4827fc8ee264ea0fa1a046d82)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2008 Isilon Inc http://www.isilon.com/
5  * Authors: Doug Rabson <dfr@rabson.org>
6  * Developed with Red Inc: Alfred Perlstein <alfred@freebsd.org>
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 #include <sys/param.h>
31 #include <sys/kernel.h>
32 #include <sys/kobj.h>
33 #include <sys/lock.h>
34 #include <sys/malloc.h>
35 #include <sys/module.h>
36 #include <sys/mutex.h>
37 #include <sys/priv.h>
38 #include <sys/proc.h>
39 
40 #include <kgssapi/gssapi.h>
41 #include <kgssapi/gssapi_impl.h>
42 #include <rpc/rpc.h>
43 #include <rpc/rpc_com.h>
44 #include <rpc/rpcsec_gss.h>
45 
46 #include "gssd.h"
47 #include "kgss_if.h"
48 
49 MALLOC_DEFINE(M_GSSAPI, "GSS-API", "GSS-API");
50 
51 struct kgss_mech_list kgss_mechs;
52 struct mtx kgss_gssd_lock;
53 
54 CLIENT *kgss_gssd_handle;
55 
56 static int
57 kgss_load(void)
58 {
59 	CLIENT *cl;
60 	struct timeval nulltimo = {.tv_sec = 0, .tv_usec = 200000};
61 
62 	LIST_INIT(&kgss_mechs);
63 
64 	cl = client_nl_create("kgss", GSSD, GSSDVERS);
65 	KASSERT(cl, ("%s: netlink client already exist", __func__));
66 
67 	/*
68 	 * The transport default is no retries at all, since there could
69 	 * be no userland listener to our messages.  Initially, a short timeout
70 	 * is set, so that a Null RPC upcall will fail quickly if the daemon
71 	 * is not running.  After the Null RPC succeeds, we will retry for 5
72 	 * minutes with 10 second interval.  This will potentially cure hosts
73 	 * with misconfigured startup, where kernel starts sending GSS queries
74 	 * before userland had started up the gssd(8) daemon.
75 	 * The initial timeout of 200usec is for the Null RPC.
76 	 */
77 	clnt_control(cl, CLSET_RETRIES, &(int){30});
78 	clnt_control(cl, CLSET_TIMEOUT, &nulltimo);
79 
80 	/*
81 	 * We literally wait on gssd(8), let's see that in top(1).
82 	 */
83 	clnt_control(cl, CLSET_WAITCHAN, "gssd");
84 
85 	mtx_lock(&kgss_gssd_lock);
86 	kgss_gssd_handle = cl;
87 	mtx_unlock(&kgss_gssd_lock);
88 
89 	return (0);
90 }
91 
92 #if 0
93 static void
94 kgss_unload(void)
95 {
96 
97 	clnt_destroy(kgss_gssd_handle);
98 }
99 #endif
100 
101 int
102 kgss_oid_equal(const gss_OID oid1, const gss_OID oid2)
103 {
104 
105 	if (oid1 == oid2)
106 		return (1);
107 	if (!oid1 || !oid2)
108 		return (0);
109 	if (oid1->length != oid2->length)
110 		return (0);
111 	if (memcmp(oid1->elements, oid2->elements, oid1->length))
112 		return (0);
113 	return (1);
114 }
115 
116 void
117 kgss_install_mech(gss_OID mech_type, const char *name, struct kobj_class *cls)
118 {
119 	struct kgss_mech *km;
120 
121 	km = malloc(sizeof(struct kgss_mech), M_GSSAPI, M_WAITOK);
122 	km->km_mech_type = mech_type;
123 	km->km_mech_name = name;
124 	km->km_class = cls;
125 	LIST_INSERT_HEAD(&kgss_mechs, km, km_link);
126 }
127 
128 void
129 kgss_uninstall_mech(gss_OID mech_type)
130 {
131 	struct kgss_mech *km;
132 
133 	LIST_FOREACH(km, &kgss_mechs, km_link) {
134 		if (kgss_oid_equal(km->km_mech_type, mech_type)) {
135 			LIST_REMOVE(km, km_link);
136 			free(km, M_GSSAPI);
137 			return;
138 		}
139 	}
140 }
141 
142 gss_OID
143 kgss_find_mech_by_name(const char *name)
144 {
145 	struct kgss_mech *km;
146 
147 	LIST_FOREACH(km, &kgss_mechs, km_link) {
148 		if (!strcmp(km->km_mech_name, name)) {
149 			return (km->km_mech_type);
150 		}
151 	}
152 	return (GSS_C_NO_OID);
153 }
154 
155 const char *
156 kgss_find_mech_by_oid(const gss_OID oid)
157 {
158 	struct kgss_mech *km;
159 
160 	LIST_FOREACH(km, &kgss_mechs, km_link) {
161 		if (kgss_oid_equal(km->km_mech_type, oid)) {
162 			return (km->km_mech_name);
163 		}
164 	}
165 	return (NULL);
166 }
167 
168 gss_ctx_id_t
169 kgss_create_context(gss_OID mech_type)
170 {
171 	struct kgss_mech *km;
172 	gss_ctx_id_t ctx;
173 
174 	LIST_FOREACH(km, &kgss_mechs, km_link) {
175 		if (kgss_oid_equal(km->km_mech_type, mech_type))
176 			break;
177 	}
178 	if (!km)
179 		return (NULL);
180 
181 	ctx = (gss_ctx_id_t) kobj_create(km->km_class, M_GSSAPI, M_WAITOK);
182 	KGSS_INIT(ctx);
183 
184 	return (ctx);
185 }
186 
187 void
188 kgss_delete_context(gss_ctx_id_t ctx, gss_buffer_t output_token)
189 {
190 
191 	KGSS_DELETE(ctx, output_token);
192 	kobj_delete((kobj_t) ctx, M_GSSAPI);
193 }
194 
195 OM_uint32
196 kgss_transfer_context(gss_ctx_id_t ctx, void *lctx)
197 {
198 	struct export_sec_context_res res;
199 	struct export_sec_context_args args;
200 	enum clnt_stat stat;
201 	OM_uint32 maj_stat;
202 
203 	if (lctx != NULL) {
204 		maj_stat = KGSS_IMPORT(ctx, MIT_V1, lctx);
205 		ctx->handle = 0;
206 		return (maj_stat);
207 	}
208 
209 	args.ctx = ctx->handle;
210 	bzero(&res, sizeof(res));
211 	stat = gssd_export_sec_context_1(&args, &res, kgss_gssd_handle);
212 	if (stat != RPC_SUCCESS) {
213 		return (GSS_S_FAILURE);
214 	}
215 
216 	maj_stat = KGSS_IMPORT(ctx, res.format, &res.interprocess_token);
217 	ctx->handle = 0;
218 
219 	xdr_free((xdrproc_t) xdr_export_sec_context_res, &res);
220 
221 	return (maj_stat);
222 }
223 
224 void
225 kgss_copy_buffer(const gss_buffer_t from, gss_buffer_t to)
226 {
227 	to->length = from->length;
228 	if (from->length) {
229 		to->value = malloc(from->length, M_GSSAPI, M_WAITOK);
230 		bcopy(from->value, to->value, from->length);
231 	} else {
232 		to->value = NULL;
233 	}
234 }
235 
236 /*
237  * Acquire the kgss_gssd_handle and return it with a reference count,
238  * if it is available.
239  */
240 CLIENT *
241 kgss_gssd_client(void)
242 {
243 	CLIENT *cl;
244 	struct rpc_callextra ext;
245 	enum clnt_stat stat;
246 	struct timeval rpctimo = {.tv_sec = 300, .tv_usec = 0};
247 	static time_t nextrpc = 0;
248 	static bool done_upcall = false;
249 
250 	mtx_lock(&kgss_gssd_lock);
251 	cl = kgss_gssd_handle;
252 	if (!done_upcall) {
253 		mtx_unlock(&kgss_gssd_lock);
254 		/*
255 		 * Can only be NULL if client_nl_create() called from
256 		 * kgss_load() returns NULL.
257 		 */
258 		if (cl == NULL)
259 			return (cl);
260 		if (time_uptime < nextrpc)
261 			return (NULL);
262 		/*
263 		 * Do a Null RPC with a short timeout.  If the RPC succeeds,
264 		 * the gssd daemon is running.  If the Null RPC fails, don't
265 		 * again for 5sec.
266 		 */
267 		memset(&ext, 0, sizeof(ext));
268 		ext.rc_auth = authnone_create();
269 		stat = clnt_call_private(cl, &ext, NULLPROC,
270 		    (xdrproc_t)xdr_void, NULL, (xdrproc_t)xdr_void, NULL,
271 		    rpctimo);	/* rpctimo is ignored by clnt_nl_call(). */
272 		AUTH_DESTROY(ext.rc_auth);
273 		if (stat != RPC_SUCCESS) {
274 			nextrpc = time_uptime + 5;
275 			return (NULL);
276 		}
277 		CLNT_CONTROL(cl, CLSET_TIMEOUT, &rpctimo);
278 		mtx_lock(&kgss_gssd_lock);
279 		done_upcall = true;
280 	}
281 	if (cl != NULL)
282 		CLNT_ACQUIRE(cl);
283 	mtx_unlock(&kgss_gssd_lock);
284 	return (cl);
285 }
286 
287 /*
288  * Kernel module glue
289  */
290 static int
291 kgssapi_modevent(module_t mod, int type, void *data)
292 {
293 	int error = 0;
294 
295 	switch (type) {
296 	case MOD_LOAD:
297 		rpc_gss_entries.rpc_gss_refresh_auth = rpc_gss_refresh_auth;
298 		rpc_gss_entries.rpc_gss_secfind = rpc_gss_secfind;
299 		rpc_gss_entries.rpc_gss_secpurge = rpc_gss_secpurge;
300 		rpc_gss_entries.rpc_gss_seccreate = rpc_gss_seccreate;
301 		rpc_gss_entries.rpc_gss_set_defaults = rpc_gss_set_defaults;
302 		rpc_gss_entries.rpc_gss_max_data_length =
303 		    rpc_gss_max_data_length;
304 		rpc_gss_entries.rpc_gss_get_error = rpc_gss_get_error;
305 		rpc_gss_entries.rpc_gss_mech_to_oid = rpc_gss_mech_to_oid;
306 		rpc_gss_entries.rpc_gss_oid_to_mech = rpc_gss_oid_to_mech;
307 		rpc_gss_entries.rpc_gss_qop_to_num = rpc_gss_qop_to_num;
308 		rpc_gss_entries.rpc_gss_get_mechanisms = rpc_gss_get_mechanisms;
309 		rpc_gss_entries.rpc_gss_get_versions = rpc_gss_get_versions;
310 		rpc_gss_entries.rpc_gss_is_installed = rpc_gss_is_installed;
311 		rpc_gss_entries.rpc_gss_set_svc_name = rpc_gss_set_svc_name;
312 		rpc_gss_entries.rpc_gss_clear_svc_name = rpc_gss_clear_svc_name;
313 		rpc_gss_entries.rpc_gss_getcred = rpc_gss_getcred;
314 		rpc_gss_entries.rpc_gss_set_callback = rpc_gss_set_callback;
315 		rpc_gss_entries.rpc_gss_clear_callback = rpc_gss_clear_callback;
316 		rpc_gss_entries.rpc_gss_get_principal_name =
317 		    rpc_gss_get_principal_name;
318 		rpc_gss_entries.rpc_gss_svc_max_data_length =
319 		    rpc_gss_svc_max_data_length;
320 		rpc_gss_entries.rpc_gss_ip_to_srv_principal =
321 		    rpc_gss_ip_to_srv_principal;
322 		mtx_init(&kgss_gssd_lock, "kgss_gssd_lock", NULL, MTX_DEF);
323 		error = kgss_load();
324 		break;
325 	case MOD_UNLOAD:
326 #if 0
327 		kgss_unload();
328 		mtx_destroy(&kgss_gssd_lock);
329 #endif
330 		/*
331 		 * Unloading of the kgssapi module is not currently supported.
332 		 * If somebody wants this, we would need to keep track of
333 		 * currently executing threads and make sure the count is 0.
334 		 */
335 		/* FALLTHROUGH */
336 	default:
337 		error = EOPNOTSUPP;
338 	}
339 	return (error);
340 }
341 static moduledata_t kgssapi_mod = {
342 	"kgssapi",
343 	kgssapi_modevent,
344 	NULL,
345 };
346 DECLARE_MODULE(kgssapi, kgssapi_mod, SI_SUB_VFS, SI_ORDER_SECOND);
347 MODULE_DEPEND(kgssapi, xdr, 1, 1, 1);
348 MODULE_DEPEND(kgssapi, krpc, 1, 1, 1);
349 MODULE_VERSION(kgssapi, 1);
350