1 /*
2  *  linux/net/sunrpc/gss_mech_switch.c
3  *
4  *  Copyright (c) 2001 The Regents of the University of Michigan.
5  *  All rights reserved.
6  *
7  *  J. Bruce Fields   <bfields@umich.edu>
8  *
9  *  Redistribution and use in source and binary forms, with or without
10  *  modification, are permitted provided that the following conditions
11  *  are met:
12  *
13  *  1. Redistributions of source code must retain the above copyright
14  *     notice, this list of conditions and the following disclaimer.
15  *  2. Redistributions in binary form must reproduce the above copyright
16  *     notice, this list of conditions and the following disclaimer in the
17  *     documentation and/or other materials provided with the distribution.
18  *  3. Neither the name of the University nor the names of its
19  *     contributors may be used to endorse or promote products derived
20  *     from this software without specific prior written permission.
21  *
22  *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
23  *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
24  *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
25  *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
27  *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
28  *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
29  *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
30  *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
31  *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
32  *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
33  *
34  */
35 
36 #include <linux/types.h>
37 #include <linux/slab.h>
38 #include <linux/module.h>
39 #include <linux/oid_registry.h>
40 #include <linux/sunrpc/msg_prot.h>
41 #include <linux/sunrpc/gss_asn1.h>
42 #include <linux/sunrpc/auth_gss.h>
43 #include <linux/sunrpc/svcauth_gss.h>
44 #include <linux/sunrpc/gss_err.h>
45 #include <linux/sunrpc/sched.h>
46 #include <linux/sunrpc/gss_api.h>
47 #include <linux/sunrpc/clnt.h>
48 
49 #ifdef RPC_DEBUG
50 # define RPCDBG_FACILITY        RPCDBG_AUTH
51 #endif
52 
53 static LIST_HEAD(registered_mechs);
54 static DEFINE_SPINLOCK(registered_mechs_lock);
55 
56 static void
57 gss_mech_free(struct gss_api_mech *gm)
58 {
59 	struct pf_desc *pf;
60 	int i;
61 
62 	for (i = 0; i < gm->gm_pf_num; i++) {
63 		pf = &gm->gm_pfs[i];
64 		kfree(pf->auth_domain_name);
65 		pf->auth_domain_name = NULL;
66 	}
67 }
68 
69 static inline char *
70 make_auth_domain_name(char *name)
71 {
72 	static char	*prefix = "gss/";
73 	char		*new;
74 
75 	new = kmalloc(strlen(name) + strlen(prefix) + 1, GFP_KERNEL);
76 	if (new) {
77 		strcpy(new, prefix);
78 		strcat(new, name);
79 	}
80 	return new;
81 }
82 
83 static int
84 gss_mech_svc_setup(struct gss_api_mech *gm)
85 {
86 	struct pf_desc *pf;
87 	int i, status;
88 
89 	for (i = 0; i < gm->gm_pf_num; i++) {
90 		pf = &gm->gm_pfs[i];
91 		pf->auth_domain_name = make_auth_domain_name(pf->name);
92 		status = -ENOMEM;
93 		if (pf->auth_domain_name == NULL)
94 			goto out;
95 		status = svcauth_gss_register_pseudoflavor(pf->pseudoflavor,
96 							pf->auth_domain_name);
97 		if (status)
98 			goto out;
99 	}
100 	return 0;
101 out:
102 	gss_mech_free(gm);
103 	return status;
104 }
105 
106 int
107 gss_mech_register(struct gss_api_mech *gm)
108 {
109 	int status;
110 
111 	status = gss_mech_svc_setup(gm);
112 	if (status)
113 		return status;
114 	spin_lock(&registered_mechs_lock);
115 	list_add(&gm->gm_list, &registered_mechs);
116 	spin_unlock(&registered_mechs_lock);
117 	dprintk("RPC:       registered gss mechanism %s\n", gm->gm_name);
118 	return 0;
119 }
120 
121 EXPORT_SYMBOL_GPL(gss_mech_register);
122 
123 void
124 gss_mech_unregister(struct gss_api_mech *gm)
125 {
126 	spin_lock(&registered_mechs_lock);
127 	list_del(&gm->gm_list);
128 	spin_unlock(&registered_mechs_lock);
129 	dprintk("RPC:       unregistered gss mechanism %s\n", gm->gm_name);
130 	gss_mech_free(gm);
131 }
132 
133 EXPORT_SYMBOL_GPL(gss_mech_unregister);
134 
135 struct gss_api_mech *
136 gss_mech_get(struct gss_api_mech *gm)
137 {
138 	__module_get(gm->gm_owner);
139 	return gm;
140 }
141 
142 EXPORT_SYMBOL_GPL(gss_mech_get);
143 
144 static struct gss_api_mech *
145 _gss_mech_get_by_name(const char *name)
146 {
147 	struct gss_api_mech	*pos, *gm = NULL;
148 
149 	spin_lock(&registered_mechs_lock);
150 	list_for_each_entry(pos, &registered_mechs, gm_list) {
151 		if (0 == strcmp(name, pos->gm_name)) {
152 			if (try_module_get(pos->gm_owner))
153 				gm = pos;
154 			break;
155 		}
156 	}
157 	spin_unlock(&registered_mechs_lock);
158 	return gm;
159 
160 }
161 
162 struct gss_api_mech * gss_mech_get_by_name(const char *name)
163 {
164 	struct gss_api_mech *gm = NULL;
165 
166 	gm = _gss_mech_get_by_name(name);
167 	if (!gm) {
168 		request_module("rpc-auth-gss-%s", name);
169 		gm = _gss_mech_get_by_name(name);
170 	}
171 	return gm;
172 }
173 EXPORT_SYMBOL_GPL(gss_mech_get_by_name);
174 
175 static struct gss_api_mech *gss_mech_get_by_OID(struct rpcsec_gss_oid *obj)
176 {
177 	struct gss_api_mech	*pos, *gm = NULL;
178 	char buf[32];
179 
180 	if (sprint_oid(obj->data, obj->len, buf, sizeof(buf)) < 0)
181 		return NULL;
182 	dprintk("RPC:       %s(%s)\n", __func__, buf);
183 	request_module("rpc-auth-gss-%s", buf);
184 
185 	spin_lock(&registered_mechs_lock);
186 	list_for_each_entry(pos, &registered_mechs, gm_list) {
187 		if (obj->len == pos->gm_oid.len) {
188 			if (0 == memcmp(obj->data, pos->gm_oid.data, obj->len)) {
189 				if (try_module_get(pos->gm_owner))
190 					gm = pos;
191 				break;
192 			}
193 		}
194 	}
195 	spin_unlock(&registered_mechs_lock);
196 	return gm;
197 }
198 
199 static inline int
200 mech_supports_pseudoflavor(struct gss_api_mech *gm, u32 pseudoflavor)
201 {
202 	int i;
203 
204 	for (i = 0; i < gm->gm_pf_num; i++) {
205 		if (gm->gm_pfs[i].pseudoflavor == pseudoflavor)
206 			return 1;
207 	}
208 	return 0;
209 }
210 
211 static struct gss_api_mech *_gss_mech_get_by_pseudoflavor(u32 pseudoflavor)
212 {
213 	struct gss_api_mech *gm = NULL, *pos;
214 
215 	spin_lock(&registered_mechs_lock);
216 	list_for_each_entry(pos, &registered_mechs, gm_list) {
217 		if (!mech_supports_pseudoflavor(pos, pseudoflavor)) {
218 			module_put(pos->gm_owner);
219 			continue;
220 		}
221 		if (try_module_get(pos->gm_owner))
222 			gm = pos;
223 		break;
224 	}
225 	spin_unlock(&registered_mechs_lock);
226 	return gm;
227 }
228 
229 struct gss_api_mech *
230 gss_mech_get_by_pseudoflavor(u32 pseudoflavor)
231 {
232 	struct gss_api_mech *gm;
233 
234 	gm = _gss_mech_get_by_pseudoflavor(pseudoflavor);
235 
236 	if (!gm) {
237 		request_module("rpc-auth-gss-%u", pseudoflavor);
238 		gm = _gss_mech_get_by_pseudoflavor(pseudoflavor);
239 	}
240 	return gm;
241 }
242 
243 EXPORT_SYMBOL_GPL(gss_mech_get_by_pseudoflavor);
244 
245 /**
246  * gss_mech_list_pseudoflavors - Discover registered GSS pseudoflavors
247  * @array: array to fill in
248  * @size: size of "array"
249  *
250  * Returns the number of array items filled in, or a negative errno.
251  *
252  * The returned array is not sorted by any policy.  Callers should not
253  * rely on the order of the items in the returned array.
254  */
255 int gss_mech_list_pseudoflavors(rpc_authflavor_t *array_ptr, int size)
256 {
257 	struct gss_api_mech *pos = NULL;
258 	int j, i = 0;
259 
260 	spin_lock(&registered_mechs_lock);
261 	list_for_each_entry(pos, &registered_mechs, gm_list) {
262 		for (j = 0; j < pos->gm_pf_num; j++) {
263 			if (i >= size) {
264 				spin_unlock(&registered_mechs_lock);
265 				return -ENOMEM;
266 			}
267 			array_ptr[i++] = pos->gm_pfs[j].pseudoflavor;
268 		}
269 	}
270 	spin_unlock(&registered_mechs_lock);
271 	return i;
272 }
273 
274 u32
275 gss_svc_to_pseudoflavor(struct gss_api_mech *gm, u32 service)
276 {
277 	int i;
278 
279 	for (i = 0; i < gm->gm_pf_num; i++) {
280 		if (gm->gm_pfs[i].service == service) {
281 			return gm->gm_pfs[i].pseudoflavor;
282 		}
283 	}
284 	return RPC_AUTH_MAXFLAVOR; /* illegal value */
285 }
286 EXPORT_SYMBOL_GPL(gss_svc_to_pseudoflavor);
287 
288 /**
289  * gss_mech_info2flavor - look up a pseudoflavor given a GSS tuple
290  * @info: a GSS mech OID, quality of protection, and service value
291  *
292  * Returns a matching pseudoflavor, or RPC_AUTH_MAXFLAVOR if the tuple is
293  * not supported.
294  */
295 rpc_authflavor_t gss_mech_info2flavor(struct rpcsec_gss_info *info)
296 {
297 	rpc_authflavor_t pseudoflavor;
298 	struct gss_api_mech *gm;
299 
300 	gm = gss_mech_get_by_OID(&info->oid);
301 	if (gm == NULL)
302 		return RPC_AUTH_MAXFLAVOR;
303 
304 	pseudoflavor = gss_svc_to_pseudoflavor(gm, info->service);
305 
306 	gss_mech_put(gm);
307 	return pseudoflavor;
308 }
309 
310 u32
311 gss_pseudoflavor_to_service(struct gss_api_mech *gm, u32 pseudoflavor)
312 {
313 	int i;
314 
315 	for (i = 0; i < gm->gm_pf_num; i++) {
316 		if (gm->gm_pfs[i].pseudoflavor == pseudoflavor)
317 			return gm->gm_pfs[i].service;
318 	}
319 	return 0;
320 }
321 
322 EXPORT_SYMBOL_GPL(gss_pseudoflavor_to_service);
323 
324 char *
325 gss_service_to_auth_domain_name(struct gss_api_mech *gm, u32 service)
326 {
327 	int i;
328 
329 	for (i = 0; i < gm->gm_pf_num; i++) {
330 		if (gm->gm_pfs[i].service == service)
331 			return gm->gm_pfs[i].auth_domain_name;
332 	}
333 	return NULL;
334 }
335 
336 EXPORT_SYMBOL_GPL(gss_service_to_auth_domain_name);
337 
338 void
339 gss_mech_put(struct gss_api_mech * gm)
340 {
341 	if (gm)
342 		module_put(gm->gm_owner);
343 }
344 
345 EXPORT_SYMBOL_GPL(gss_mech_put);
346 
347 /* The mech could probably be determined from the token instead, but it's just
348  * as easy for now to pass it in. */
349 int
350 gss_import_sec_context(const void *input_token, size_t bufsize,
351 		       struct gss_api_mech	*mech,
352 		       struct gss_ctx		**ctx_id,
353 		       gfp_t gfp_mask)
354 {
355 	if (!(*ctx_id = kzalloc(sizeof(**ctx_id), gfp_mask)))
356 		return -ENOMEM;
357 	(*ctx_id)->mech_type = gss_mech_get(mech);
358 
359 	return mech->gm_ops
360 		->gss_import_sec_context(input_token, bufsize, *ctx_id, gfp_mask);
361 }
362 
363 /* gss_get_mic: compute a mic over message and return mic_token. */
364 
365 u32
366 gss_get_mic(struct gss_ctx	*context_handle,
367 	    struct xdr_buf	*message,
368 	    struct xdr_netobj	*mic_token)
369 {
370 	 return context_handle->mech_type->gm_ops
371 		->gss_get_mic(context_handle,
372 			      message,
373 			      mic_token);
374 }
375 
376 /* gss_verify_mic: check whether the provided mic_token verifies message. */
377 
378 u32
379 gss_verify_mic(struct gss_ctx		*context_handle,
380 	       struct xdr_buf		*message,
381 	       struct xdr_netobj	*mic_token)
382 {
383 	return context_handle->mech_type->gm_ops
384 		->gss_verify_mic(context_handle,
385 				 message,
386 				 mic_token);
387 }
388 
389 /*
390  * This function is called from both the client and server code.
391  * Each makes guarantees about how much "slack" space is available
392  * for the underlying function in "buf"'s head and tail while
393  * performing the wrap.
394  *
395  * The client and server code allocate RPC_MAX_AUTH_SIZE extra
396  * space in both the head and tail which is available for use by
397  * the wrap function.
398  *
399  * Underlying functions should verify they do not use more than
400  * RPC_MAX_AUTH_SIZE of extra space in either the head or tail
401  * when performing the wrap.
402  */
403 u32
404 gss_wrap(struct gss_ctx	*ctx_id,
405 	 int		offset,
406 	 struct xdr_buf	*buf,
407 	 struct page	**inpages)
408 {
409 	return ctx_id->mech_type->gm_ops
410 		->gss_wrap(ctx_id, offset, buf, inpages);
411 }
412 
413 u32
414 gss_unwrap(struct gss_ctx	*ctx_id,
415 	   int			offset,
416 	   struct xdr_buf	*buf)
417 {
418 	return ctx_id->mech_type->gm_ops
419 		->gss_unwrap(ctx_id, offset, buf);
420 }
421 
422 
423 /* gss_delete_sec_context: free all resources associated with context_handle.
424  * Note this differs from the RFC 2744-specified prototype in that we don't
425  * bother returning an output token, since it would never be used anyway. */
426 
427 u32
428 gss_delete_sec_context(struct gss_ctx	**context_handle)
429 {
430 	dprintk("RPC:       gss_delete_sec_context deleting %p\n",
431 			*context_handle);
432 
433 	if (!*context_handle)
434 		return GSS_S_NO_CONTEXT;
435 	if ((*context_handle)->internal_ctx_id)
436 		(*context_handle)->mech_type->gm_ops
437 			->gss_delete_sec_context((*context_handle)
438 							->internal_ctx_id);
439 	gss_mech_put((*context_handle)->mech_type);
440 	kfree(*context_handle);
441 	*context_handle=NULL;
442 	return GSS_S_COMPLETE;
443 }
444